Plural Channels For Transmission Of A Single Pulse Train

Plural Channels For Transmission Of A Single Pulse Train patent applications listed are from June 2005 to current and include Date, Patent Application Number, Patent Title, Patent Abstract summary and are linked to the corresponding patent application page.

11/22/07 - 20070268976 - Frequency offset correction for an ultrawideband communication system
A method and a receiver system for subcarrier-specific frequency offset correction including frequency offset estimation, updating and compensation. The method includes initial frequency offset estimation in time domain using packet preamble, frequency offset compensation during channel estimation symbols using the initial frequency offset estimate, and frequency offset update tracking during ...

11/22/07 - 20070268975 - Method and structure of configuring preamble to support transmission of data symbol in a wireless communication system
A method of configuring a data packet including an orthogonal frequency division multiplexing (OFDM) preamble in a wireless communication system is disclosed. The method includes configuring the data packet to include the OFDM preamble in a first region, a pilot and medium access control (MAC) in a second region, and ...

11/22/07 - 20070268974 - Method for detecting ofdm timing in ofdm system
A scheme for detecting a symbol timing (synchronization) of an Orthogonal Frequency Division Multiplexing (OFDM) system in which a transmitting end inserts a Cyclic Prefix (CP) and/or a Cyclic Suffix (CS) in an OFDM symbol for transmission, and a receiving end uses a new timing metric to detect a timing ...

11/15/07 - 20070263741 - Efficient reduced complexity windowed optimal time domain equalizer for discrete multitone-based dsl modems
An algorithm for computing an efficient, reduced complexity, windowed optimal linear time domain equalizer for a dispersive channel comprises the steps of determining a window of maximum energy in the impulse response of length equal to or less than a number of cyclic prefix samples associated with a received digital ...

11/15/07 - 20070263740 - Harq method in a mobile communication system
A method for allocating resources in an Orthogonal Frequency Division Multiple Access (OFDMA) mobile communication system where data is transmitted by Hybrid Automatic Repeat reQuest (HARQ) is provided, in which a multiplexing mode is selected for multiplexing a Distributed Resource Channel (DRCH) and Localized Resource Channel (LRCH) over orthogonal frequency ...

11/15/07 - 20070263739 - Method and system for managing memory in a communication system using hybrid automatic repeat request (harq)
A method and system for managing memory using Hybrid Automatic Repeat Request in a communication system is provided. The method includes storing a retransmitted burst in a memory. The retransmitted burst includes plurality of bits. One or more of memory address of the retransmitted burst and the information corresponding to ...

11/15/07 - 20070263737 - Transmitting apparatus, receiving apparatus, communication system and communication method
A receiving apparatus that can effectively use spectra to improve the interference resistance and the information transmission efficiency. In this apparatus, a channel estimating part (1006) uses a pilot received from the transmitting end to perform a channel estimation for each of subcarrier groups. A subcarrier group performance analyzer (1011) ...

11/15/07 - 20070263736 - Multicarrier communication apparatus and multicarrier communication method
A multicarrier communication apparatus and the like wherein the arithmetic amount required for calculating a reception weight by which a multicarrier signal is to be multiplied is suppressed, while the reception characteristic for the multicarrier signal is improved. In the apparatus, a subcarrier transmission weight generating part (513) generates a ...

11/15/07 - 20070263735 - Wireless communication methods, systems, and signal structures
Systems and methods for performing OFDM MIMO communications are provided. These include a frame structure; methods of combining various types of MIMO such as STTD and SM; sub-channel definitions; sub-FFT channel constructions; fast control channels; additional modulations; and group antenna transmit diversity; new incremental redundancy schemes. ...

11/08/07 - 20070258529 - Method and system of orthogonalizing signal transmitted from bs applied to ofdm access
A method of orthogonalizing signals transmitted from a BS in an OFDMA system, at a transmitting end, includes a) performing encoding, interleaving and modulation on original information bits; b) allocating sub-carriers with equivalent intervals to a sub-channel, and dividing channels into two parts of a cell edge user channel and ...

11/08/07 - 20070258528 - Apparatus for reducing clipping noise in a broadband wireless communication system and method thereof
Provided are an apparatus for reducing clipping noise in a broadband wireless communication system in which a clipping method is used and a method thereof. The method includes, when clipped signals are received, decoding and equalizing the received signals to determine transmitted symbols, comparing the magnitudes of the amplitudes of ...

11/08/07 - 20070258527 - Fast dynamic noise detection/adaptation system for dsl modems
A systems and a method for a DMT-based DSL modem to detect time-varying noise dynamically during transmission and adapt to its rapid changes promptly by increasing or reducing data rate while maintaining the transmission and utilizing maximum channel capacity. A DMT-based modem reserves a first set of sub-channels to detect ...

11/08/07 - 20070258525 - Method and apparatus to support scalability in a multicarrier network
A multicarrier communication device can vary the number of subcarriers being used to carry on multicarrier communication within a network, based on a predetermined criterion (e.g., traffic load, etc.). ...

11/08/07 - 20070258524 - Phase offset tracking method for tracking a phase offset and device thereof
The invention relates to a phase offset tracking module and method for tracking a phase offset, and in particular, to a phase offset tracking module and method for tracking a phase offset in a receiver. A phase offset tracking method comprises: utilizing a first and a second registers to respectively ...

11/01/07 - 20070253500 - Method for multiple use subchannels
Methods for multiple use subchannels are provided. In one embodiment, a method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system comprises: establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host ...

11/01/07 - 20070253498 - Radio transmitting apparatus and radio transmitting method in multicarrier communication
A radio transmitting apparatus wherein unnecessary consumption of transmission power can be suppressed and PAPR (Peak to Average Power Ratio) can be reduced in multicarrier communication. In the apparatus, a repetition part (105) replicates (repeats) each symbol outputted from a modulating part (103) to generate and output a plurality of ...

11/01/07 - 20070253496 - Wireless communication system having linear encoder
In general, linear complex-field encoding techniques are proposed For example, transmitter of a wireless communication system includes an encoder and a modulator. The encoder linearly encodes a data stream to produce an encoded data stream. The modulator to produce an output waveform in accordance with the encoded data stream for ...

10/25/07 - 20070248176 - Radio transmission device and radio transmission method in multi-carrier communication
There is provided a radio transmission device capable of improving the system throughput in multi-carrier communication. The device includes IQ separation units (20-1 to 2O-K) for separating an I channel and a Q channel from the inputted symbol and inputting them into control units (22). The control units (22-1 to ...

10/25/07 - 20070248175 - Method for generating preamble structures and signaling structures in a mimo ofdm transmission system
The disclosure relates to a method for generating preamble structures and signaling structures for a data signal in a MIMO-OFDM transmission system with a multitude of antennas. To this end, the preamble structure has, for each antenna, a synchronization section with a predetermined synchronization sequence and has a channel estimation ...

10/25/07 - 20070248174 - Method and system for implementing multiple-in-multiple-out ofdm wireless local area network
A method and associated systems for implementing MIMO communication systems are disclosed. The systems comprise at least one encoder (120a, 120b) for Reed-Solomon encoding a corresponding input data stream of data packets; at least one interleaver (124a, 124b) for interleaving bits of a corresponding encoded input data stream, at least ...

10/25/07 - 20070248173 - Ofdma based on cognitive radio
A multiuser scheme allowing for a number of users, sets of user, or carriers to share one or more channels is provided. In the invention, the available channel bandwidth is subdivided into a number of equal-bandwidth subchannels according to standard OFDM practice. The transmitter is informed by an application that ...

10/25/07 - 20070248172 - System and method for transmitting signals in cooperative base station multi-user mimo networks
A method transmits and receives signals in a cooperative, multi-user, multi-input, multi-output network. The network includes base stations (BSs) and mobile stations (MSs). Each BS has at least two antennas, and each MS has at least one antenna. At a first base station and a second base station using linear ...

10/18/07 - 20070242769 - Method, system and apparatus for implementing soft frequency reuse in wireless communication system
The embodiments of the present invention disclose a method, system and apparatus for implementing soft frequency reuse in a wireless communication system, the method includes: selecting for a cell or sector at least one carrier as a primary carrier and at least one carrier as a secondary carrier, the primary ...

10/18/07 - 20070242768 - Noise estimation for wireless communication
Techniques for deriving and using noise estimate for data reception in a wireless communication system are described. A noise estimate may be derived for each packet received in a data transmission. Data detection may then be performed for each packet using the noise estimate for that packet. For noise estimation, ...

10/18/07 - 20070242767 - Method and apparatus for performing joint channel equalization
A method and apparatus for performing joint channel equalization (JCE) are disclosed. JCE is implemented to reject inter-cell and intra-cell interference in a receiver. The JCE only requires the channel responses of a desired signal and interferers with respect to different antennas. In order to implement JCE, a number of ...

10/18/07 - 20070242766 - Rate control for multi-channel communication systems
Various methods and systems for determining reverse-link data rates in a multi-user communication system are disclosed. For example, an apparatus for controlling a data rate of at least a first UE in a multi-user communication system is disclosed. The apparatus may include a channel estimation device configured to determine channel ...

10/18/07 - 20070242762 - Power control in a multicarrier communications system
An improvement to multi-carrier communication, such as an OFDM and MC-CDMA system, where in a multipath or phase distorted channel, the received signal is flat with respect to frequency and linear with respect to phase. A first unit transmits a plurality of multi-carrier signals, which include unmodulated carrier signals. A ...

10/18/07 - 20070242761 - Method and apparatus for channel estimation
The invention relates to DVB-T system, and in particular, to a channel estimation method for OFDM symbols. A plurality of symbols are received to generate a pilot response. A finite impulse response is generated from the pilot response. A coefficient table is selected based on the characteristics of the finite ...

10/18/07 - 20070242760 - Speed estimation method for telecommunication system
A speed estimation method is provided, detecting relative speed of a transmitter and a receiver transmitting symbols by OFDM sub-carriers through a channel. First, a first correlation table is established, indicating conceptual relationships between the relative speed and the channel characteristic based on Doppler shift theory. Thereafter, channel characteristic caused ...

10/11/07 - 20070237249 - Method and device for estimating the transfer function of the transmission channel for a cofdm demodulator
A method of COFDM demodulation of symbols, each including first carriers conveying data and pilots having their frequency positions varying at least partly from one symbol to the next symbol. The method includes, for each symbol, a step of determining a first estimate of the transfer function of the channel ...

10/11/07 - 20070237248 - Apparatus and method for allocating resources and performing communication in a wireless communication system
Disclosed is a method for allocating resources in a base station of a wireless communication system that performs communication using frequency resources. The method includes dividing subcarriers into subcarrier sets each including a predetermined number of consecutive subcarriers, and generating a resource index table mapped to consecutive indexes such that ...

10/11/07 - 20070237244 - Method for implementing an equalizer of an ofdm baseband receiver
A method for implementing an equalizer of an orthogonal frequency division multiplexing (OFDM) baseband receiver is provided. The OFDM baseband receiver includes a channel estimation and tracking module for estimating a channel impulse response of an input signal of the equalizer. A conjugate of the channel impulse response is first ...

10/04/07 - 20070230605 - Method and arrangement in wireless communication networks using relaying
The present invention relates to wireless communication systems wherein relaying is used to enhance performance. According to the method and arrangement of the invention artificial frequency selectivity and spatial diversity is provided by introducing delay diversity. A OFDM chunk is subjected to a 2D cyclic prefix by pre-appending to a ...

10/04/07 - 20070230601 - Channel estimation method and apparatus using linear interpolation scheme in orthogonal frequency division multiplexing system and receiver using the same
Disclosed are a channel estimation method and a channel estimation apparatus, and a receiver using the same. The channel estimation apparatus provided in the receiver detects pilot signals from radio signals and estimates channels of the detected pilot signals. The channel estimation apparatus estimates channels corresponding to data by conducting ...

10/04/07 - 20070230600 - Random access structure for wireless networks
Apparatus and methods for accessing a wireless telecommunications network by transmitting a random access signal. The random access signal includes a random access preamble signal selected from a set of random access preamble signals constructed by cyclically shift selected root CAZAC sequences. The random access signal may be one or ...

10/04/07 - 20070230599 - Multicarrier communication apparatus, integrated circuit, and multicarrier communication method
Channel estimation unit 16 includes CNR calculation unit 17, threshold setting unit 18, and modulation method determination unit 19. CNR calculation unit 17 calculates a CNR for each of a plurality of subcarriers from a received multicarrier communication signal. Threshold setting unit 18 takes statistics of a plurality of calculated ...

10/04/07 - 20070230595 - System and method for beamforming using rate-dependent feedback in a wireless network
Embodiments of multicarrier receiver and method for beamforming using rate-dependent feedback in a wireless network are generally described herein. Other embodiments may be described and claimed. In some embodiments, decimated beamforming matrices are generated for groups of two or more subcarriers and provided to a multicarrier transmitter. The number of ...

10/04/07 - 20070230594 - Multi-band ofdm uwb communication systems having improved frequency diversity
Methods and apparatus for transmitting and receiving symbols in a communication system having a plurality of frequency bands are provided. A first symbol is transmitted on a first tone using a first constellation mapping and a second symbol is transmitted on a second tone using a second constellation mapping different ...

10/04/07 - 20070230593 - Joint optimization of transmitter and receiver pulse-shaping filters
A method for jointly designing a transmitter pulse-shaping filter and a receiver pulse-shaping filter having respective filter coefficients includes defining one or more performance-related variables based on at least some of the filter coefficients of the transmitter and receiver pulse-shaping filters. One or more constraints applicable to one or more ...

10/04/07 - 20070230592 - Method of detecting a frame boundary of a received signal in digital communication system and apparatus of enabling the method
A method of detecting a frame boundary of a received signal in a digital communication system, the method including: generating a delayed signal by delaying the received signal by a predetermined period; calculating a correlation value by correlating the received signal with the delayed signal for a predetermined correlation length ...

10/04/07 - 20070230591 - Apparatus for estimating and compensating carrier frequency offset and data receiving method in receiver of wireless communication system
The present invention relates to an apparatus for estimating and compensating a carrier frequency offset, and a data receiving method in a receiver of a wireless communication system. The apparatus correlates a received signal with a signal delayed by a predetermined period of the received signal in a correlation window, ...

10/04/07 - 20070230590 - Method and apparatus for searching cells utilizing down link preamble signal
An apparatus for searching for a cell in a mobile communication system, including: a preamble sequence storage unit storing preamble sequences each of which corresponds to one preamble index, and a cell searching unit correlating a received signal and the stored preamble sequences in a time domain and identifying the ...

10/04/07 - 20070230589 - Method for allocation of power in multiuser orthogonal frequency division multiplexing
Power allocation methods for multiuser orthogonal frequency division multiplexing (OFDM) are described. Arbitrary partitioning of the OFDM tones among users and arbitrary modulation formats, possibly different for every user, are considered. Two systems of receivers and transmitters and corresponding methods address power allocation, respectively for slow fading channels tracked instantaneously ...

10/04/07 - 20070230588 - System, method and device of adjusting a wireless communication signal
Embodiments of the present invention provide a system, method, and apparatus of adjusting a wireless communication signal. In some demonstrative embodiments the method may include, for example, allocating a plurality of spectral components to an adjustment signal based on a spectral range of the wireless communication signal to be adjusted ...

09/27/07 - 20070223611 - Communications apparatus and communications system using multicarrier transmission mode
A communications system for communications by a multicarrier transmission mode between a plurality of communications apparatuses (10, 20) wherein an overall frequency band assigned to the communications system is divided into a plurality of frequency bands each having a constant bandwidth (for example band 1 to band 4) and a ...

09/27/07 - 20070223610 - Sparse channel estimation for orthogonal frequency division multiplexed signals
A computationally efficient channel estimation technique for use within an orthogonal frequency division multiplexing (OFDM) communication system determines coefficients of a channel transfer function by calculating the dot products of a pilot vector and a plurality of interpolation vectors. One dot product is preferably calculated for each subcarrier of interest ...

09/27/07 - 20070223606 - Method and apparatus for interference mitigation in an ofdma-based communication system
A method and apparatus for mitigating inter-cell interference in an OFDMA-based wireless communication system is disclosed. The method includes the steps of, providing at least a frame in a base station to a plurality of mobile stations; dividing the frame into a plurality of subcarriers; assigning a demarcation line within ...

09/27/07 - 20070223605 - Method and apparatus for correcting sampler clock frequency offset in ofdm mimo systems
In an orthogonal frequency division multiplexed (OFDM) multiple-in multiple-out (MIMO) wireless communication system, a method for correcting sampler clock frequency offset in a receiver comprises acquiring the frequency offset and symbol timing in a received signal by the receiver. The estimated value of a fractional offset is computed, and a ...

09/27/07 - 20070223604 - Wireless terminal and communication system switching method
A wireless terminal 100A is compatible with an OFCDM system and has a signal processing section 151, a synchronous detection section 162, etc. The signal processing section 151 performs Fourier transform when the wireless terminal is compatible with the OFCDM system; the signal processing section 151 performs Fourier transform and ...

09/27/07 - 20070223603 - Wireless terminal apparatus, control method for wireless base station and control method for wireless terminal apparatus
The present invention provides a wireless terminal apparatus, including a reception unit for receiving a multi-carrier signal generated by applying an N-point (where N is a natural number) inverse fast Fourier transform (IFFT) to a plurality of sub-carriers to which transmission information for a plurality of wireless terminal apparatuses is ...

09/27/07 - 20070223602 - Orthogonal frequency division multiplexing (ofdm) system receiver using low-density parity-check (ldpc) codes
Arrangements relating to an Orthogonal Frequency Division Multiplexing (OFDM) receiver (200) can include performing at least one Low-Density Parity Check (LDPC) decoding attempt on a received signal (725) and evaluating at least one parity check for each LDPC decoding attempt (735). Failed LDPC decoding attempts can be counted according to ...

09/27/07 - 20070223601 - Method of providing signal diversity in an ofdm system
A method and apparatus is provided for transceiving an information signal in an orthogonal frequency division multiplexed (OFDM) communication system that uses a plurality of radio frequency subcarriers modulated with the information signal and transceives the modulated plurality of radio frequency subcarriers through first and second antennas at a transmitter ...

09/20/07 - 20070217535 - Orthogonal frequency division multiplexing (ofdm) receiver, ofdm reception method and terrestrial digital receiver
In an OFDM receiver, one of a plurality of antennas is selected based on a ratio X of two moving average integration values (first moving average integration value and second moving average integration value) that are calculated from a non-delay symbol and a delay symbol. It could be said that ...

09/20/07 - 20070217533 - Apparatus and method for channel estimation in a wireless communication system
An apparatus and method for channel estimation in a wireless communication system are provided, in which a first channel estimate is calculated using a pilot signal included in a received signal, a data signal included in the received signal is demodulated using the first channel estimate, a second channel estimate ...

09/20/07 - 20070217532 - Apparatus and method for acquiring frame synchronization in broadband wireless communication system
Provided are an apparatus and a method for acquiring frame synchronization in a broadband wireless communication system using a plurality of preamble sub-carrier patterns. The apparatus includes a plurality of preamble detectors that perform phase compensation on input sample data in accordance with a corresponding pattern and computes correlation values ...

09/20/07 - 20070217530 - Method and apparatus for channel estimation using time-frequency localized pilots and de-noising techniques
A method and apparatus for performing channel estimation using time-frequency localized pilots and de-noising techniques are disclosed. A transmitter sends pilot symbols which are localized in a joint time-frequency domain to a receiver for channel estimation. The receiver receives the pilot symbols and performs a time-frequency analysis, such as a ...

09/20/07 - 20070217528 - Data transmission device, radio reception device, radio transmission method, and radio reception method
A radio transmission device capable of improving the reception error rate characteristics of a receiver. In this device, an FFT (Fast Fourier Transform) unit (102) subjects a transmission signal to an FFT operation, in which a signal in a time domain is converted into a signal in a frequency domain. ...

09/20/07 - 20070217525 - Frequency tracking which adapts to timing synchronization
A frequency tracking method and apparatus is provided. A receiver receives OFDM symbols and determines associated frequency offset. A frequency error estimator selects a cross correlation window for determining frequency offset based on timing offset. A symbol timing estimator is used to determine the timing offset. ...

09/20/07 - 20070217524 - Frame timing synchronization for orthogonal frequency division multiplexing (ofdm)
A frame timing synchronization technique for orthogonal frequency division multiplexing (OFDM) systems is presented. First, a coarse synchronization technique generates a coarse frame timing estimate. The coarse synchronization technique applies a sliding window differentiator to the output of a conventional auto-correlator to mitigate the plateau effect associated with conventional auto-correlation ...

09/13/07 - 20070211811 - Reduced complexity channel estimation for wireless communication systems
Techniques to derive a channel estimate using substantially fewer number of complex multiplications than with a brute-force method to derive the same channel estimate. In one method, an intermediate vector B is initially derived based on K sub-vectors of a vector Ĥ for a channel frequency response estimate and at ...

09/13/07 - 20070211810 - Adaptive subcarrier loading
A wireless multicarrier transmission method in which a multicarrier transmission uses n modulated frequency subcarriers (n is an integer number), and a fading condition of each subcarrier is detected to generate fading channel profile information. The modulation of each subcarrier includes selecting a standard modulation scheme, a lower modulation scheme, ...

09/13/07 - 20070211809 - Apparatus and method for estimating symbol timing offset in a wireless communication system
A method for estimating a symbol timing offset in an Orthogonal Frequency Division Multiplexing (OFDM) communication system is disclosed. The method includes detecting a channel impulse response within one Fast Fourier Transform (FFT) duration; and estimating a symbol timing offset taking the detected channel impulse response into account. The symbol ...

09/13/07 - 20070211808 - Method for self-calibration in a mobile receiver
Provided is an apparatus and method for calibrating an imbalance characteristic of a received signal of a frequency domain in a mobile receiver which supports an Orthogonal Frequency Division Multiplexing (OFDM) scheme. To this end, a received signal of a radio frequency band is converted into a baseband signal by ...

09/13/07 - 20070211807 - Apparatus for controlling papr and method thereof
An apparatus for controlling PAPR in an OFDM communication system and method thereof are disclosed, by which implementation is simplified and enhanced PAPR characteristics are provided. The present application includes outputting GNb data symbols by oversampling Nb parallel data symbols, spreading the oversampled data symbols using DFT, and mapping the ...

09/06/07 - 20070206693 - Adaptive modulation in multipoint-to-point communication using orthogonal frequency division multiplexing
Systems for adaptive modulation in multipoint-to-point communication using orthgonal frequency division multiplexing (OFDM) are provided. In one embodiment, a system comprises: a host unit; and a plurality of remote units using a multiple access scheme to communicate at the same time with the host unit using OFDM; wherein the host ...

09/06/07 - 20070206692 - Method and apparatus for detecting offset in an orthogonal frequency division multiplexing system
Disclosed is a method for detecting a frequency offset in an Orthogonal Frequency Division Multiplexing (OFDM) system. The method includes determining a first frequency index based on autocorrelation values calculated according to a frequency index for a pilot signal of a received symbol, accumulating the autocorrelation values calculated according to ...

09/06/07 - 20070206691 - Apparatus and method for transmitting an uplink signal in a mobile communication system using an ofdma scheme
Disclosed is a method for transmitting an uplink signal by a mobile station in a mobile communication system using an OFDMA scheme. The method includes estimating a downlink channel status by using a signal received from a base station; determining a precoding matrix by using the estimated downlink channel status; ...

09/06/07 - 20070206690 - Device and method for generating a multi-channel signal or a parameter data set
For flexibly signaling a synchronous mode or an asynchronous mode in the multi-channel parameter reconstruction, a parameter configuration cue is inserted in the data stream, which is used by a configurator on the side of a multi-channel decoder to configure a multi-channel reconstructor. If the parameter configuration cue has a ...

09/06/07 - 20070206689 - Method and apparatus for channel estimation in an orthogonal frequency division multiplexing system
In an orthogonal frequency division multiplexing (OFDM) system, a frequency domain channel estimate for non-nullified subcarriers is converted to a time domain channel estimate. The number of taps L of a channel model is determined based on the time domain channel estimate. An improved time domain channel estimate is obtained ...

09/06/07 - 20070206687 - Memory efficient ofdm channel estimation and frequency domain diversity processing
A frequency domain diversity DVB receiver device includes multiple antenna ports for receiving radio signals, and radio signal processing circuits connected to the antenna ports that convert the received radio signals into digital samples. The digital samples from the different antenna ports time-share a front-end processor which processes the digital ...

09/06/07 - 20070206686 - Method and apparatus for performing cyclic-shift diversity with beamforming
Cyclic-shift diversity transmission and optional per-subcarrier transmit beamforming within a same time interval (e.g., OFDM symbol interval) takes place. The CSD transmission technique circularly shifts the IFFT output prior to any cyclic prefix insertion and has the effect of putting a subcarrier and antenna dependent phase shift in the effective ...

08/30/07 - 20070201573 - System for variable forward error correction in a multipoint to point orthogonal frequency division multiplexing system
Systems for variable forward error correction in a multipoint to point orthogonal frequency division multiplexing system are provided. In one embodiment, bidirectional communication system comprises: a first remote unit for communicating with a host unit using orthogonal frequency division multiplexing, the host unit communicatively coupled to a plurality of remote ...

08/30/07 - 20070201572 - Method and apparatus for transmission and reception within an ofdm communication system
In an OFDM system the same Walsh code is used at the same time for a plurality of transmitters. The multiple transmitters can be from the same, or different devices (e.g., different base stations on the downlink, different terminals on the uplink). Each subcarrier/antenna combination will share a similar pilot ...

08/30/07 - 20070201571 - Method and device for estimating the transfer function of the transmission channel for a cofdm demodulator
A method of COFDM demodulation of successive symbols, each symbol comprising data carriers and pilots. The method includes, for each symbol, the determination of estimates of the transfer function of the channel for the symbol carriers, including the steps of determining, for first carriers such that, for the frequency positions ...

08/30/07 - 20070201569 - Apparatus, method and computer program product providing joint detection for increasing throughout with data in uplink that multiplexes users using codes and that multiplexes users using frequency multiplexing
First information is detected in a received wideband signal. The first information is conveyed by a plurality of multiplexed frequency bands, individual ones of the multiplexed frequency bands corresponding to individual ones of first users and to a transport format. Detecting includes making data decisions corresponding to the first information. ...

08/30/07 - 20070201568 - Apparatus and method for estimating carrier-to-interference and noise ratio in a broadband wireless communication system
An apparatus and method for estimating the CINR of an uplink channel in a broadband wireless communication system are provided, in which tiles being subcarrier sets are separated from a feedback signal received on the uplink channel. All symbols included in the tiles of the feedback signal are correlated with ...

08/30/07 - 20070201567 - Device and method for clipping multicarrier signal
A device and a method for clipping multicarrier signal are provided. The method for clipping multicarrier signal includes: detecting whether an Idle Period in DownLink (IPDL) starts in each subcarrier forming a multicarrier joint signal and generating an IPDL flag just when the IPDL starts in a subcarrier; detecting power ...

08/30/07 - 20070201566 - Techniques for explicit feedback delay measurement
Techniques for explicit feedback delay measurement are described. An apparatus may comprise a processor to generate a steering matrix for transmit spatial processing over a channel, determine a delay time associated with explicit feedback information for the channel, and determine whether to modify the steering matrix with the explicit feedback ...

08/23/07 - 20070195902 - Method for variable forward error correction in a multi-point to point orthogonal frequency division multiplexing system
Methods for variable forward error correction in a multi-point to point orthogonal frequency division multiplexing system are provided. In one emboidment, a method for an orthogonal frequency division multiplexing multipoint-to-point communications system comprises: establishing communication between a first remote unit of a plurality of remote units and a host unit, ...

08/23/07 - 20070195901 - Method and system for adaptive modulation
Methods and systems for adaptive modulation are provided. In one embodiment, a method for a plurality of remote units of an orthogonal frequency division multiplexing multipoint-to-point communications system comprises: establishing communication between a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the ...

08/23/07 - 20070195900 - Apparatus and method for controlling dynamic range of weight vectors according to combining methods in a mobile station equipped with multiple antennas in high rate packet data system using code division multiple access scheme
Provided is an apparatus and method for controlling a dynamic range of weight vectors according to a combining method to fit an input range of a channel decoder in a mobile station of a high rate packet data system. The apparatus includes a channel estimator for receiving pilot symbol from ...

08/23/07 - 20070195898 - Narrow band interference cancellation technique for ofdm transmitters
A computational algorithm provides new and effective interference cancellation of the in-band spurious signals for the Orthogonal Frequency Division Multiplex (OFDM) transmitters. This new interference cancellation transmits non-zero tones may be used to cancel the interference generated by the modulated data signals. This minimizes the number of tones used and ...

08/23/07 - 20070195897 - Reception quality notifying method, wireless communication terminal apparatus, and base station apparatus
A reception quality notifying method is disclosed which improves the upstream line throughput by reducing the data mount of reception quality data of downstream multicarrier signals to be transmitted to a base station apparatus in the upstream line. There are also disclosed a base station apparatus and a wireless communication ...

08/16/07 - 20070189403 - Method and device for phase noise compensation in ofdm/ofdma receivers, and receiver employing the method and the device
In one aspect, a compensation of phase noise is performed downstream from a Discrete Fourier Transformer converting received signals in the time domain into signals in the frequency domain wherein a linear transversal equaliser working on the signals in the frequency domain for reducing both the common phase error and ...

08/16/07 - 20070189402 - Method and apparatus for channel state information generation in a dvb-t receiver
A method and apparatus for channel state information generation in a DVB receiver. The present invention comprises: obtaining the magnitude of an error signal and a channel response signal of a sub-carrier; combining the magnitude of the error signal and the magnitude of the channel response signal of each sub-carrier; ...

08/09/07 - 20070183522 - Measuring interference and noise power using non-content burst periods
Embodiments describe a method of measuring noise and interference within transceivers of an OFDM wireless transmission system, or similar communication system, including a number of receivers communicating with one or more base stations in cell or sector arrangements. The transmitter schedules a transmission burst for a non-existent user (receiver) using ...

08/09/07 - 20070183519 - Method for channel estimation in orthogonal frequency division multiplexing system and device thereof
A method for channel estimation in an Orthogonal Frequency Division Multiplexing (OFDM) system, including: a transmitter determining a distribution density of pilot OFDM symbols according to the maximum Doppler frequency shift supported by the system, and transmitting pilot OFDM symbols and data OFDM symbols based on the distribution density of ...

08/09/07 - 20070183518 - Method and apparatus for estimating timing error and frequency offset of mimo system
The present invention relates to a method and device for estimating a timing error and a frequency offset in the MIMO mobile communication system. In a system including a plurality of transmit antennas and a plurality of receive antennas, a predetermined preamble symbol is inserted into a frame to be ...

08/09/07 - 20070183517 - Symmetrical data signal processing
In a digital communications receiver configured to receive, via a communications channel, a received first signal representing a sequence of symbols, each symbol being encoded to be representative of data bits, a method of processing the received signal includes adjusting a magnitude, filtering, and applying cyclic prefix restoration, to the ...

08/09/07 - 20070183516 - Wireless communications system employing ofdma and cdma techniques
Disclosed is an Orthogonal Frequency Division Multiple Access (OFDMA) based wireless communications system operable to communicate OFDMA type signals over a set of dynamically assigned orthogonal sub-carriers and Code Division Multiple Access (CDMA) type signals over a set of pre-allocated orthogonal sub-carriers. The OFDMA system utilizes pre-allocated orthogonal sub-carriers for ...

08/09/07 - 20070183515 - Method and apparataus for transmitting data in a multi-antenna wireless system
The invention is to improve the throughput for a wireless transmission. Multiple antennas are activated in the same frequency at the same time to facilitate parallel transmission. A systematic processes are provided to achieve high throughput transmission. ...

08/09/07 - 20070183514 - Orthogonal frequency division multiplexing receiver
A receiver for orthogonal frequency division multiplexing signals, including an A/D converter (52) for converting receiver analog signals to a digital signal data stream, wherein the digital signal data stream includes symbols separated by guard segments. The receiver also includes an I/Q demodulator (54) for producing a first set of ...

08/02/07 - 20070177686 - System and method for pre-fft ofdm fine synchronization
A synchronization unit for performing timing synchronization in the time domain includes storage, a multiplier, a signal analyzer, and a timing error estimation unit. The storage stores a reference signal. The multiplier calculates a sum of minus one product shift and a sum of plus one product shift based on ...

08/02/07 - 20070177683 - Wireless communication system
A transmitting circuit 111 in a base station apparatus 110 has an MLI modulation part 248 composed of an MLI generating circuit 238, a symbol modulation circuit 239, and an IFFT circuit 240, a user data modulation part 249 composed of an encoder circuit 234, a symbol modulation circuit 235, ...

08/02/07 - 20070177682 - Method and apparatus for generating and transmitting code sequence in a wireless communication system
A method of generating a code sequence in a wireless communication system is disclosed. More specifically, the method includes recognizing a desired length of the code sequence, generating a code sequence having a length different from the desired length, and modifying the length of the generated code sequence to equal ...

08/02/07 - 20070177681 - Mimo-ofdm system using eigenbeamforming method
Disclosed is a MIMO-OFDM system, wherein the transmitter comprises a serial/parallel converter for converting continuously inputted symbols of the number of subcarriers to K parallel signals; a signal reproducer for reproducing K parallel signals by the number of transmit antennas L an eigenmode generator for generating eigenbeam of the reproduced ...

08/02/07 - 20070177680 - Emulating system, apparatus, and method for emulating a radio channel
Apparatus, and an associated method, for modeling a channel impulse response of a radio channel. The model emulates an actual radio channel and is formed of non-diffuse as well as diffuse components. The model is used, for example, to test mobile stations for their compliance with E-911 phase II mandates. ...

07/26/07 - 20070171993 - Adaptive overlap and add circuit and method for zero-padding ofdm system
The invention relates to an Overlap and Add circuit, and in particular, an adaptive Overlap and Add circuit. The adaptive OLA circuit comprises a detection unit, an estimator, and an OLA circuit. The detection unit estimates a channel property according to an OFDM signal received through a channel. The estimator ...

07/19/07 - 20070165734 - Method and apparatus for domain transformation multiple signal processing
A method and apparatus of joint processing a plurality of digital signal streams is disclosed. The method includes transforming a plurality of the digital signal streams from an original domain to a lower complexity processing domain. The transformed plurality of digital signal streams are joint processed, wherein the joint processing ...

07/19/07 - 20070165733 - Reception apparatus
A reception apparatus includes a plurality of antennas for receiving modulation signals of channels in the same frequency band, an received signal strength intensity estimation unit for estimating the reception received signal strength intensity of each reception signal, transmission path fluctuation estimation units for estimating a transmission path fluctuation of ...

07/19/07 - 20070165729 - Apparatus and method for receiving data in a wireless communication system using bit interleaving, symbol interleaving and symbol mapping
An apparatus and method are provided for receiving data generated by sequentially performing bit interleaving, symbol interleaving and symbol mapping in a wireless communication system. A fast Fourier transform (FFT) processor receives in-phase/quadrature phase (I/Q) data of a radio channel generated by sequentially performing bit interleaving, symbol interleaving and symbol ...

07/19/07 - 20070165728 - Multi-symbol signals including an initial symbol and an extension portion
A base station generates and transmits a multi-symbol beacon/timing synchronization signal. The multi-symbol beacon/timing synchronization signal includes: (i) an initial symbol including a body portion and a cyclic prefix, the cyclic prefix preceding the body portion and being generated from an end portion of the body portion and (ii) an ...

07/19/07 - 20070165727 - Approximate linear fm synchronization symbols for a bandwidth configurable ofdm modem
A communications system permits bandwidth configurability using a linear frequency modulated (LFM) waveform for transmitter/receiver synchronization. The system permits enhancement of MIL-STD-1553 data buses, and is likewise applicable to any bandwidth-configurable modem. ...

07/19/07 - 20070165726 - Apparatus and method for channel estimation using training signals with reduced signal overhead
A base station comprising an antenna array including M antennas for transmitting data to a plurality of subscriber stations. The base station generates a first pilot signal preamble by adding a first cyclic prefix to a first pilot signal sequence and generates a second pilot signal preamble by adding a ...

07/12/07 - 20070160159 - Device and method of performing channel estimation for ofdm-based wireless communication system
A device and method of performing channel estimation for an OFDM-based wireless communication system performs a Least Square interpolation with a statistical channel profile consideration on pilot channel estimates to derive data channel estimates at data subcarrier locations. ...

07/12/07 - 20070160158 - Ofdma device and method of correcting frequency offset in ofdma signals
An Orthogonal Frequency Division Multiple Access (OFDMA) device and method of correcting frequency offset in OFDMA signals computes an estimated frequency offset, which is used for mixing an incoming OFDMA signal with a frequency offset-compensated mixer signal and for digitally correcting sampling errors in the signal. ...

07/12/07 - 20070160157 - Radio transmitter apparatus, radio receiver apparatus, and wireless communication system
A wireless communication system capable of obtaining diversity gain without fail even when the distribution of the reception qualities is large. radio transmitter apparatus (100) of the wireless communication system, a repetition/constellation pattern ratio deciding part (113) adjusts the number of constellations to be used by a modulating part (102) ...

07/12/07 - 20070160156 - Wireless communication device employing interference-sensitive mode selection and associated methods
Embodiments of a wireless communication system employing interference-sensitive mode selection and associated methods are generally introduced. ...

07/05/07 - 20070153932 - Ofdm communication system and method having a reduced peak-to-average power ratio
An OFDM system embeds sequence information in the transmitted signal that reduces peak average power ratio (PAP) with minimal impact on the overall system efficiency. A marker is embedded onto the transmitted information that is used to identify the combining (inversion) sequence at the receiver. In one embodiment, selected tones ...

07/05/07 - 20070153931 - Apparatus and method for determining pilot pattern in a broadband wireless access communication system
An apparatus and method for determining a pilot pattern in a Broadband Wireless Access (BWA) communication system are provided. In the pilot pattern determining method, an Orthogonal Frequency Division Multiplexing (OFDM) demodulator generates frequency-domain data by fast-Fourier-transform (FFT)-processing a received signal. A pilot pattern decider calculates a coherence bandwidth and ...

07/05/07 - 20070153930 - Apparatus, method and computer program product providing joint synchronization using semi-analytic root-likelihood polynomials for ofdm systems
A method includes determining a number of observations. Each observation occurs at an observation time and corresponds to one of a number of received frequency multiplexed training symbols. The method also includes determining a number of roots of a first polynomial equation that is a function of a variable corresponding ...

07/05/07 - 20070153928 - Harq method and system
Embodiments of the present invention include one HARQ method and system in which the data is transmitted/received with N transmit antennas and M receive antennas, wherein each transmit antenna transmits data by using L subcarriers, M and N are natural numbers and L is the multiple of 2. The method ...

07/05/07 - 20070153927 - Receiver apparatus of the adaptive ici cancellation iterative receiver in wireless communication system and ici cancellation method
An ICI cancellation iterative receiver and an ICI cancellation method in the wireless communication system is provided. In order to eliminate the Inter-carrier-interference (ICI) due to phase noise, an adaptive ICI cancellation scheme based on the wireless communication system is presented. In order to correct the contaminated preamble symbols due ...

07/05/07 - 20070153926 - System and method for improved channel estimation for wireless ofdm systems
In accordance with an embodiment of the present invention, a novel system and method for MMSE channel estimation are provided that take synchronization errors, either intentional or unintentional, into account during the channel estimation process. The proposed channel estimation in accordance with the present invention improves the noise averaging capability ...

07/05/07 - 20070153925 - Method and apparatus for dynamic switching of space-time coding/decoding method
The present invention provides dynamic switching technique for space-time coding/decoding mode based on channel status information for a MIMO-OFDM system, in which a method for dynamic switching of space-time coding mode comprises: determining step for determining a space-time coding mode based on feedback information by a transmitter; mapping step for ...

07/05/07 - 20070153923 - Method and apparatus for providing a link adaptation scheme for a wireless communication system
An approach is provided for error correction in a multi-carrier wireless network or an Orthogonal Frequency Division Multiplexing (OFDM) network. A first rate is assigned to a first error correction channel. A second rate is assigned to a second error correction channel, wherein the first rate is different from the ...

07/05/07 - 20070153922 - Receiver and method for channel estimation for multicarrier communication systems
Embodiments of system and method for generating channel estimates in a wireless network are generally described herein. Other embodiments may be described and claimed. In some embodiments, a linear interpolator uses refined cross-correlation and autocorrelation estimates and pilot subcarrier estimates to generate channel estimates for the current OFDM data symbol. ...

06/28/07 - 20070147529 - Frequency domain equalization method and apparatus for a single carrier receiver
A frequency-domain-equalization apparatus for a receiver in single-carrier communication comprising: a selection means (103) for selecting a time-sequence-signal portion from a received signal that is longer than one block; a Fourier-transformation means (104) for performing Fourier transformation of the time-sequence-signal portion that is longer than one block and converting the ...

06/28/07 - 20070147528 - Apparatus and method for transmitting multi-carrier signals
Embodiments of the present invention may provide an apparatus and a method for transmitting a multi-carrier signal, the multi-carrier signal being generated by modulating a received digital signal. The received digital signal may be modulated to a first multi-carrier signal and a second multi-carrier signal. The first multi-carrier signal and ...

06/28/07 - 20070147527 - Ofdm signal transmitting method and transmitter and receiver thereof
A transmitting method of OFDM signal includes allocating first and second channel estimation preamble signals for channel response estimation respectively to +kth and −kth subcarriers from center frequency of first OFDM signal, allocating first and second pilot signals for residual phase offset estimation respectively to +kth and −kth subcarriers from ...

06/28/07 - 20070147526 - Sub-carrier diversity method on multi-band orthogonal-frequency-division-multiplexing symbol
A sub-carrier diversity method on an MB-OFDM (multi-band orthogonal-frequency-division-multiplexing) system repeatedly transmitting an identical frequency band of an identical symbol, including: setting a value of a TDS (time domain spreading) of sub-carriers depending on a transmission rate; and shifting the positions of the sub-carriers in a predetermined unit so that ...

06/28/07 - 20070147525 - Apparatus and method for controlling gain in an interference cancellation receiver of an ofdma system
A gain control apparatus of an interference cancellation receiver that performs interference cancellation in a frequency axis in an Orthogonal Frequency Division Multiple Access (OFDMA) system. A first signal power measurer measures first signal power of a received signal that was received from a base station and then underwent fast ...

06/28/07 - 20070147524 - Method and device for notching the transmission band of an analog signal, in particular an mb-ofdm signal
The transmission band of an analog signal to be transmitted is notched, including sub-carriers to be modulated from digital modulation coefficients respectively associated with the sub-carriers. The method includes providing an initial digital signal from successive frequency-domain groups each containing the digital modulation coefficients respectively associated to the sub-carriers. The ...

06/28/07 - 20070147522 - Integrated circuit capable of independently operating a plurality of communication channels
An apparatus according to one embodiment may include an integrated circuit. The integrated circuit may include a plurality communication channels. The integrated circuit may be is capable of communicating with at least one remote node external to the integrated circuit, via at least one of the communication channels, in accordance ...

06/28/07 - 20070147521 - Interleaver design with multiple encoders for more than two transmit antennas in high throughput wlan communication systems
A MIMO communication system implements an interleaver design with multiple encoders for more than two transmit antennas for high throughput WLAN communication systems. Multiple encoders are utilized in the transmitter and multiple decoders are utilized in the receiver, wherein each encoder operates at lower clock speed than would be necessary ...

06/28/07 - 20070147520 - Techniques to time vary pilot locations in wireless networks
An embodiment of the present invention provides an apparatus, comprising a receiver 5 capable of selecting optimal pilot locations and providing feedback of the pilot locations to a transmitter in communication with the receiver. The optimal pilot locations may be selected by locations that avoid strong interference or platform noise ...

06/21/07 - 20070140367 - Crest factor reduction system and method for ofdm transmission systems using selective sub-carrier degradation
A system and method for crest factor reduction of OFDM transmission systems using selective sub-carrier degradation, is disclosed. A modulated communications signal comprising a series of symbols is converted into parallel format in groups of plural symbols in the frequency domain. Crest factor reduction reduces a primary peak of the ...

06/21/07 - 20070140366 - Method for estimating and compensating carrier frequency offset
One inventive aspect relates to a method of estimating carrier frequency offset introduced on an RF multicarrier signal received via a transmission channel on a direct downconversion analog receiver. The method comprises generating a preamble comprising at least one set of training symbols. The method further comprises transmitting the preamble ...

06/21/07 - 20070140365 - Beamforming transceiver architecture with enhanced channel estimation and frequency offset estimation capabilities in high throughput wlan systems
A method and system for transmitting bit streams in a telecommunication system, by combining a bit stream with a first portion of a preamble, applying power loading to the combined bit stream, applying eigen-steering to the power loaded bit stream, and combining a second portion of the preamble with the ...

06/21/07 - 20070140364 - Interleaver for ieee 802.11n standard
A MIMO wireless system includes a transmitter having a parser that parses a bit stream into multiple spatial data streams and multiple interleavers corresponding to the multiple spatial data streams, where each interleaver interleaves the bits in the corresponding spatial data stream by performing frequency rotation after an interleaving operation, ...

06/21/07 - 20070140363 - Method of link adaptation in mimo beamforming systems
An apparatus and method for closed-loop signaling over multiple channels in a telecommunication system. Channel condition for each channel is obtained, and transmission rate per channel is determined according to channel condition. The information bit streams is transmitted via the multiple channels over a plurality of transmitter antennas according to ...

06/21/07 - 20070140362 - Radio transmitter with reduced power consumption
A technique for controlling a transmitter apparatus is useful for reducing power consumption, and may be particularly applicable to portable apparatuses such as mobile transceivers which employ a battery power supply. According to an exemplary embodiment, the transmitter apparatus includes a power amplifier for amplifying a transmission signal. A processor ...

06/14/07 - 20070133705 - Method for synchronizing seamless rate adaptation
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

06/14/07 - 20070133704 - Method for seamlessly changing power modes in an adsl system
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

06/14/07 - 20070133703 - Terminal demodulation apparatus and method
A terminal demodulation apparatus previously stores a received frame signal in a memory before inputting the same into a fast Fourier transform (FFT) unit, performs a demodulation to necessary information read from the corresponding memory, and has a separate data subcarrier memory and pilot subcarrier memory, and uses the signal ...

06/14/07 - 20070133702 - Signal transmitting and receiving apparatuses
The present invention relates to signal transmitting/receiving apparatuses. The signal transmitting apparatus includes an inverse discrete Fourier transform module, a cyclic prefix adding module, a preamble adding module, and a digital-analog converting module. The inverse discrete Fourier transform module receives modulated data, performs inverse discrete Fourier transform, and generates a ...

06/14/07 - 20070133701 - Radio communications device and radio communications controlling method
The present invention aims at ensuring both delayed wave resistance and fading resistance in good balance. A delay time measuring unit measures delay time determined based on a time point of a subcarrier out of a plurality of subcarriers arriving first and a time point of another subcarrier arriving through ...

06/14/07 - 20070133700 - Method for blind channel estimation
Provided is a method for channel estimation increasing frequency band efficiency lost by using a pilot, and reducing sensitivity to channel zero, instability, and complexity. The method includes the steps of: (a) generating an i-th symbol block Si including N carriers; (b) performing an inverse fast Fourier transform (IFFT) operation ...

06/14/07 - 20070133699 - Apparatus and method for recovering frequency in an orthogonal frequency division multiplexing system
An apparatus and method for recovering a carrier frequency of a received signal using a predefined symbol in an OFDM system is provided. A maximum value detector detects at least three values and their corresponding offsets in descending order among auto-correlation values calculated within a specific frequency offset range between ...

06/14/07 - 20070133698 - Device for compensating radio frequency distortion in orthogonal frequency division multiplexing transmission system and method thereof
The present invention relates to a device for compensating a radio frequency distortion caused by a sample/hold operation of a digital/analog converter in an orthogonal frequency division multiplexing (OFDM) transmission system, and a method thereof. In a digital transmission system, an edge frequency signal of a transmission signal band is ...

06/14/07 - 20070133697 - Method and system for synchoronizing a receiver in an ofdm system
Method and system for synchronizing a receiver in an Orthogonal Frequency Division Multiplexing (OFDM) system. The method comprises transforming (105) a received signal from the time domain into the frequency domain to produce a transformed signal. The method further comprises rotating (110) each set of ranging tones of the transformed ...

06/14/07 - 20070133696 - Kalman filter for channel estimation in ofdm systems
A scalar Kalman filter is applied for a Least-Square estimated value Hs at s. The filter has an input for receiving Hs, a filter equation and an out for the corrected estimated value Hsk for the kth variable. The filter equation is Hsk=KgainSn[k] wherein: correction Sn[k]=S+Kn(Hs−S); prediction of the correction ...

06/14/07 - 20070133695 - Method and system for channel assignment of ofdm channels
A method and system for assigning a carrier channel to a subscriber device (102) in an OFDM system is provided. The method includes estimating (602) a link impairment associated with the subscriber device. The method also includes assigning (604) the subscriber device to a carrier channel having a cyclic prefix ...

06/07/07 - 20070127584 - Fast initialization using seamless rate adaptation
A method for initializing modems in a multicarrier transmission system to establish a communication link between the transmitter and the receiver. An exemplary embodiment includes the steps of providing a predetermined parameter value that approximates a corresponding actual parameter value of the communication link, establishing a data communication link between ...

06/07/07 - 20070127583 - Digital generator and digital receiver for fdm signals
An aspect of the invention relates to a digital generator for multi-carrier frequency division multiplexing (FDM) signals. The digital generator comprises an electronic circuit being operated under the control of a computer program. The digital generator is configured to generate FDM signals being comprised of FDM symbols, wherein at least ...

06/07/07 - 20070127582 - Adaptive channel equalizer and method for equalizing channels therewith
A channel equalizer obtains channel impulse responses (CIRs) for all subcarriers by way of filtering channel impulse responses of specific subcarriers using at least two filters. One of the two filters may be a low pass filter. At least one other of the at least two filters is implemented as ...

05/31/07 - 20070121747 - Method and apparatus for transferring signals in a wireless communication system
Data is transferred in a wireless communication system, such as a wireless spread spectrum communication system. A plurality of transmitting antennas are provided. Data is encoded to produce a plurality of data streams for each of the plurality of codes. The plurality of data streams are spread with the plurality ...

05/31/07 - 20070121746 - Apparatus and method for dynamic channel allocation with low complexity in a multi-carrier communication system
A low-complexity dynamic channel allocation apparatus and method in a multi-carrier communication system are provided. In the low-complexity dynamic channel allocation method, subcarriers are initially allocated to total users and two users are selected from among all possible cases of two users out of the total users. The power gain ...

05/31/07 - 20070121745 - Filtering process for enhancing ofdma uplink reception sensitivity
Methods and systems for filtering and enhancing the uplink reception sensitivity of OFDMA hybrid point to multipoint communication systems, including the steps of: determining transmission synchronization and bandwidth allocation for a plurality of wireless clients; communicating with the wireless clients via a plurality of hybrid converters connected to a shared ...

05/31/07 - 20070121744 - Hybrid point to multipoint communication system
Methods and systems for hybrid point to multipoint communication systems, including the steps of: determining transmission synchronization and bandwidth allocation between a first wireless client and a second wireless client communicating via a common communication channel; transmitting a download multi carrier transmission, via a shared signal wired distribution line, wherein ...

05/31/07 - 20070121743 - Ubiquitous coverage ofdm hybrid system
Methods and systems for Ubiquitous coverage OFDM hybrid point to multipoint communication system, including the steps of: determining transmission synchronization and bandwidth allocation between a first wireless client and a second wireless client communicating via a common wireless communication channel, by using a wireless point to multi point centralized synchronizing ...

05/31/07 - 20070121742 - Method and apparatus for encoded signal mapping for multi-carrier communication
A communication quality is improved or signal processing is simplified in a multi-carrier communication system such as OFDM. Information different in communication quality such as systematic bits and parity bits of turbo encoded code words is combined together, and information that requires a high communication quality such as the systematic ...

05/31/07 - 20070121741 - Adaptive basis functions in a multicarrier communication system
A method for transmitting a signal uses a channel impulse response to determine a sub-carrier frequency function for at least two different basis functions. For each of the at least two sub-carrier frequency functions, a performance measure is predicted using the associated frequency function. These predicted performance measures are then ...

05/31/07 - 20070121740 - Selective attenuation in spectral notching
Processing data is disclosed. Information associated with a notch frequency spectrum is obtained. A notch signal level, associated with the notch frequency spectrum, is suppressed. A second frequency spectrum is determined based at least in part on the information associated with the notch frequency spectrum. Data associated with the second ...

05/31/07 - 20070121739 - Pilot-assisted doppler frequency estimation
A technique for estimating the Doppler frequency of an input signal comprising a pilot signal. In one embodiment, the technique comprises: (a) accumulating a plurality of samples from the input signal over a specified time duration to derive a channel tap estimate; (b) obtaining a sequence of channel tap estimates ...

05/31/07 - 20070121738 - Transmission apparatus and peak suppression method
A transmission apparatus capable of improving overall throughput of a system by suppressing peaks using some frequencies in a communication band. In this apparatus, modulation section (102) adaptively modulates transmission data. Combination section (103) combines the waveform of the transmission data and the waveform of an inverse replica and suppresses ...

05/31/07 - 20070121737 - Transmission apparatus and peak suppression method
A transmission apparatus capable of improving overall throughput of a system by suppressing peaks using some frequencies in a communication band. In this apparatus, modulation section (102) adaptively modulates transmission data. Combination section (103) combines the waveform of the transmission data and an inverse replica and suppresses peaks equal to ...

05/31/07 - 20070121736 - Method for reducing the crest factor
The invention relates to a method for reducing the crest factor of a data symbol to be transmitted in a multi-carrier data transmission system, in which the data symbol to be transmitted is a function of a multiplicity of signals provided within a predetermined data frame and each of these ...

05/24/07 - 20070116142 - Peak-to-average power reduction
A multi-carrier transmitter and transmission technique are described for transmitting payload data during a transmission time interval with reduced peak-to-average power ratio (PAPR). A multi-carrier modulator modulates subcarrier frequencies with payload data and provides a modulated signal for transmission during the transmission time interval. Excessive peaks in the modulated signal ...

05/24/07 - 20070116141 - System and method for performing ls equalization on a signal in an ofdm system
A system for performing LS equalization on a signal in an OFDM system comprises a receiver stage for receiving a modulated signal, a demodulation stage for demodulating the received modulated signal to produce a demodulated signal, a channel estimation stage for processing the demodulated signal to provide an output signal ...

05/24/07 - 20070116140 - Method for correcting soft decision value, computer program product for the same, and reception apparatus for the same
A method for correcting a soft decision value includes: demodulating a reception signal, which is coded by an error correction code and modulated in order to represent one or multiple bits with one symbol; generating the soft decision value, which is used in decoding of the error correction code; multiplying ...

05/24/07 - 20070116139 - Method and system for allocating subcarriers to subscriber devices
A method and system for allocating a plurality of subcarriers to a plurality of subscriber devices in a wireless network. A set of characteristics is identified (302) for a transmission on each of the plurality of subcarriers. A dynamic weight is assigned (304) to at least one subscriber device of ...

05/24/07 - 20070116138 - Method and system for generating beam-forming weights in an orthogonal frequency division multiplexing network
A method of generating beam-forming weights in an orthogonal frequency division multiplexing network is provided. The method includes generating a plurality of sub-bands. Each sub-band comprises a plurality of sub-carriers. A single beam-forming weight is generated for each sub-band. ...

05/24/07 - 20070116137 - Blind bandwidth detection for a sample stream
A method for determining a bandwidth of a complex valued sample stream may include correlating a first portion of a preamble symbol of the complex valued sample stream with a second portion of the preamble symbol to generate a time autocorrelated portion. The method may further include transforming the time ...

05/17/07 - 20070110178 - Configurable de-interleaver design
An integrated circuit radio transceiver and method therefor is operable to flexibly and efficiently de-interleave a received communication signal by initially changing a received signal from the time domain to the frequency domain to generate a plurality of tones that are then rearranged in a first de-interleaving step to an ...

05/17/07 - 20070110177 - Rf power distribution in the frequency domain
Data is transmitted during a transmission time interval using an available frequency bandwidth. Blocks of data to be transmitted at different power levels are identified. Multiple portions of the data blocks are distributed for transmission at different frequencies so that data blocks with higher power levels are distributed more toward ...

05/17/07 - 20070110176 - Systems and methods for improved bit-loading for discrete multi-tone modulated multiple latency applications
Systems and methods for performing bit loading in a dual latency data transmission system. In a computer network, such as an XDSL-based network, carrier channels are allocated between two latency paths. Error sensitive information is transmitted over a latency path employing one or more forward error correction techniques. Latency sensitive ...

05/17/07 - 20070110175 - Phase and frequency control of an ofdm receiver by means of pilot phase-value estimation
A common phase value of pilot subcarriers of a received data symbol (n) is estimated and used for correcting the phase of all subcarriers of the data symbol, wherein, with a time-variant frequency of the local oscillator (VCO), the estimated noisy phase values (Ψn) are used directly for the phase ...

05/17/07 - 20070110174 - Time tracking for a receiver with guard interval correlation
Techniques for performing time tracking at a receiver are described. A first arriving path (FAP) and a last arriving path (LAP) are detected based on a channel impulse response estimate for a communication channel. The detected FAP and LAP may be correct or swapped. To resolve ambiguity in the detected ...

05/17/07 - 20070110173 - Cofdm demodulator with an optimal fft analysis window positioning
The invention relates to a method for the COFDM demodulation of a signal received from a transmission channel. The inventive method includes performing the fast Fourier transform of the signal received in a window corresponding to a symbol, each symbol being associated with a guard time reproducing one part of ...

05/17/07 - 20070110172 - Channel estimation for ofdm systems
A method for performing channel estimation in an orthogonal frequency-division multiplexing system, the method including the steps of: receiving (80) transmitting pilot symbols from a plurality of transmit antennas; forming (82) a least-squares estimation matrix from the transmitted pilot symbols; forming (8488) a sparse smoothing matrix approximating a fixed weighting ...

05/17/07 - 20070110171 - Wireless communication device
A multiband OFDM_UWB transmitting and receiving apparatus is provided in Low-IF configuration to solve problems attributed to a direct-conversion transmitting and receiving apparatus. A Low-IF receiver performs sorting by rotating a sub-carrier after FFT to eliminate the need for frequency conversion using a second local signal and uses the same ...

05/10/07 - 20070104283 - Apparatus and method for transmitting/receiving data in a multi-antenna communication system
An apparatus for transmitting data in a base station of a wireless communication system that transmits data depending on channel status information fed back from terminals and uses a plurality of antennas. Based on the channel status information, a scheduler determines a terminal to which the base station will transmit ...

05/10/07 - 20070104282 - Equalization in radio receiver
A solution for equalization in a radio receiver is provided. According to the provided solution, equalization with a zero forcing equalization algorithm is improved with frequency domain processing of received information symbols. The frequency spectrum of received information symbols is modified with a calculated frequency domain representation of the radio ...

05/10/07 - 20070104281 - Method and device for monitoring carrier frequency stability of transmitters in a common wave network
The method for monitoring the stability of the carrier frequency (ωi) of identical transmitted signals (si(t)) of several transmitters Si of a single-frequency network is based upon a calculation of a carrier-frequency displacement Δωi of a carrier frequency ωi of a transmitter Si relative to a carrier frequency ω0 of ...

05/10/07 - 20070104280 - Wireless data transmission method, and corresponding signal, system, transmitter and receiver
A method for the wireless transmission of data between a transmitter and a receiver, involving the use of at least one single-carrier pilot signal and at least one signal for the transmission of data transmitted using a multicarrier modulation. A estimation of the response of the transmission channel of the ...

05/03/07 - 20070098102 - Apparatus, method and computer program product providing sub-channel assignment for relay node
Disclosed herein are apparatus, methods and computer program products providing sub-channel re-assignment performed by a relay node in a wireless communications system. In the apparatus, methods and computer program products, a relay receives an input signal made up of a plurality of sub-channels. The relay de-multiplexes the sub-channels into a ...

05/03/07 - 20070098101 - Cyclic delay diversity in a wireless system
A system includes a first transmitter, a second transmitter, and a legacy receiver. The first transmitter transmits information via a first channel to the legacy receiver. The second transmitter transmits a time-shifted version of the information via a second channel to the legacy receiver. The legacy receiver combines the information ...

05/03/07 - 20070098100 - Pilot sequence detection
A user equipment and corresponding method detect a frequency division permanent common pilot and include a controller configured to use a sliding correlator with a frequency division phase-shift, an averaging unit configured to average a peak magnitude output of the sliding correlator over a predetermined number of sub-frames for each ...

05/03/07 - 20070098099 - Precoding for segment sensitive scheduling in wireless communication systems
Techniques to enhance the performance in a wireless communication system using segments called subbands and using precoding are shown. According to one aspect, the bandwidth for transmission to an access terminal is constrained to a preferred bandwidth which is less than the bandwidth available for transmission to an access terminal ...

05/03/07 - 20070098098 - Method and apparatus for providing channel quality feedback in an orthogonal frequency division multiplexing communication system
In an Orthogonal Frequency Division Multiplexing communication system, a user equipment reports channel quality information that is sufficient to construct a fading profile of a frequency bandwidth and that does not consuming the overhead resulting from the reporting of CQI for every sub-band of the frequency bandwidth. In the communication ...

05/03/07 - 20070098097 - System and method for enhancing the performance of wireless communication systems
A system and method for enhancing the performance of a wireless communication system are disclosed. For example, a method for enhancing the performance of a wireless communication system is disclosed, which includes the steps of receiving a signal including a first plurality of sub-bands, calculating a plurality of channel quality ...

05/03/07 - 20070098096 - Wireless transmitter, signal to subcarrier allocation method for synchronizing symbol, and wireless receiver
A wireless transmitter for transmitting an OFDM symbol including a first generator to generate a plurality of first signals each including a stationary signal, a second generator to generate a plurality of second signals whose total power is less than that of the first signals, and an allocation unit configured ...

05/03/07 - 20070098095 - Method and apparatus for transmitting data in a communication system
A method and apparatus for transmitting data in a communication system. In the apparatus, a repeater repeatedly processes an input signal a predetermined number of times. A Space-Frequency Block-Coded (SFBC) encoder performs SFBC coding on the repeatedly processed input signals, and outputs at least two signal blocks in parallel. A ...

05/03/07 - 20070098094 - Peak-to-average power ratio reduction with threshold limited selection for coded ofdm systems
Disclosed is a coded orthogonal frequency-division multiplexing (OFDM) system and method for reducing a peak-to-average power ratio (PAPR). The system and method include a modulator configured to modulate (e.g., using quadrature amplitude modulation (QAM)) coded bits into symbols. The system and method also include an inverse discrete fourier transform (IDFT) ...

05/03/07 - 20070098093 - Apparatus and method for feeding back channel quality information and scheduling apparatus and method using the same in a wireless communication system
An apparatus and method are provided for feeding back channel quality information and performing scheduling using the fed-back channel quality information in a wireless communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). In the OFDMA wireless communication system, forward performance degradation due to a decrease in an amount ...

05/03/07 - 20070098092 - Multicarrier receiver and method for generating common phase error estimates for use in systems that employ two or more transmit antennas with independent local oscillators
Embodiments of system and method for generating common phase error (CPE) estimates in a multicarrier receiver are generally described herein. Other embodiments may be described and claimed. In some embodiments, the CPE estimates may be generated for each channel between two or more transmit antennas and the multicarrier receiver. ...

05/03/07 - 20070098091 - Method and system for residual frequency offset compensation of multi-carrier communication system
A residual frequency offset (RFO) compensation method and a compensation system of a multi-carrier communication system is disclosed. The compensatory method of present invention includes two phase-computation steps. The first phase-computation step processes a phase variation of an OFDM data symbol each time to obtain a RFO estimation for compensating ...

05/03/07 - 20070098090 - Systems, methods, and apparatus for mitigation of nonlinear distortion
A method among the embodiments includes calculating a value of a parameter of a nonlinear model of a signal as transmitted into a transmission channel, and applying the calculated value to obtain an estimate of data values carried by the signal. Applications to multicarrier signals are described. ...

05/03/07 - 20070098089 - Performing blind scanning in a receiver
In one embodiment, the present invention includes a method for receiving data corresponding to a portion of an incoming radio frequency (RF) spectrum, determining a set of estimates including one or more pairs of a channel frequency estimate and a symbol rate estimate from the data via a linear spectrum ...

05/03/07 - 20070098088 - Equalizer applied in mimo-ofdm system and related method
An equalizer applied in a multiple input multiple output (MIMO) orthogonal frequency division multiplex (OFDM) system for alleviating interference among a plurality of received symbol blocks is disclosed. The equalizer includes: a matched filter for extracting a preliminary equalized signal vector from a received symbol block; a blocking device for ...

04/26/07 - 20070092017 - Communications systems and methods using phase vectors
A transmitter for use, for example, in an OFDM communication system transmits a plurality of signals simultaneously to one or more receivers. Each signal carries data. At the transmitter, a suitable phase vector is selected from among a plurality of available phase vectors to apply to the plurality of signals. ...

04/26/07 - 20070092016 - Method of channel estimation
A method of channel estimation used in an orthogonal frequency division multiplexing (OFDM) system. Firstly, a plurality of synchronized signals are received respectively from a plurality of sub-channels, and the channel responses of two sub-channels are known. Then, the channel responses of other channels are estimated by the statistical property ...

04/26/07 - 20070092015 - Channel estimation in a multicarrier radio receiver
A method and apparatus for estimating channel characteristics in a multicarrier wireless receiver such as an OFDM wireless receiver. The method includes determining a channel estimate for each of a set of subcarriers by receiving multicarrier data as a result of a wireless transmission of data that includes a known ...

04/26/07 - 20070092014 - Apparatus and method for two-dimensional equalization in a communication system using orthogonal frequency division multiple access
Provided is a two-dimensional equalization method in a receiver of a communication system using an Orthogonal Frequency Division Multiple Access (OFDMA) scheme. The receiver sets as a first value a value of a 1-tap frequency domain equalizer (FEQ) corresponding to a sub-channel allocated to the receiver , and sets as ...

04/26/07 - 20070092013 - Apparatus and method for tracking symbol timing of ofdm modulation in a multi-path channel
Methods and Systems for tracking symbol timing of an OFDM signal are disclosed. In one embodiment, a wireless receiver includes signal tracking and timing logic to facilitate the timing of a demodulation operation such that the demodulation operation occurs on the proper symbol boundary, particularly when the OFDM signal has ...

04/26/07 - 20070092012 - Method and apparatus for communication channel estimation
A method and apparatus for predicting channel estimates for non-received signal frequencies provides knowledge of propagation channel characteristics for non-received frequencies. One embodiment predicts uplink (or downlink) channel estimates based on measured downlink (or uplink) channel estimates, which is advantageous in systems having different uplink and downlink frequencies. Another embodiment ...

04/19/07 - 20070086536 - Channel estimation and spatial processing for tdd mimo systems
Channel estimation and spatial processing for a TDD MIMO system. Calibration may be performed to account for differences in the responses of transmit/receive chains at the access point and user terminal. During normal operation, a MIMO pilot is transmitted on a first link and used to derive an estimate of ...

04/19/07 - 20070086535 - Pilot pattern design for a sttd scheme in an ofdm system
The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in ...

04/19/07 - 20070086534 - System and method for improving signal to quantization noise ratio of an ofdma modulator
A fixed-point IFFT device in an OFDMA digital modulator is disclosed, which comprises a sub-carrier activity detector configured to detect a number of active sub-carriers in an OFDMA symbol set being transmitted in a given OFDMA symbol period, a scale termination calculator configured to generate an output for determining at ...

04/19/07 - 20070086533 - Phase noise canceling ofdm receiver
A receiver includes, in series, at least one receive antenna, a buffer, and arithmetic logic block, a symbol detector, and a phase noise estimator. A further feedback loop couples an output of the phase noise estimator to an input of the arithmetic logic block for providing an estimate of phase ...

04/12/07 - 20070081603 - Apparatus and method for transmitting data using relay station in a broadband wireless communication system
A frame configuration method and apparatus for sending data via an RS in a broadband wireless communication system are provided. In the reception mode, the RS monitors reception of data in an (n−1)th frame from an MS and reception of data in an nth frame from a BS. The RS ...

04/12/07 - 20070081602 - Radio apparatus and communication system utilizing the same
In a combination of control signals on data signals and the data signals where the combination contains data signals to be assigned respectively to a plurality of streams, a control unit assigns a control signal contained in a leading combination and assigns a data signal, contained in the leading combination, ...

04/12/07 - 20070081601 - Blind preamble detection for an orthogonal frequency division multiplexed sample stream
A method for determining a presence of a preamble for an orthogonal frequency division multiplexed (OFDM) complex valued sample stream may include capturing a portion of the OFDM complex valued stream and autoconvolving the portion of the OFDM complex valued sample stream to generate an autoconvolved portion. The method may ...

04/05/07 - 20070076809 - Communication apparatus
A wave detecting section of a receiver has a first wavelet transformer involving a plurality of wavelet filters orthogonal to each other for performing a wavelet transform on received waveform data, a Hilbert transformer for performing a Hilbert transform on the received waveform data, a second wavelet transformer having the ...

04/05/07 - 20070076808 - Method and apparatus to track gain variation in orthogonal frequency division multiplexing (ofdm) systems
Gain variations during a packet can lead to significant performance degradation in communications systems that use high order quadrature amplitude modulation (QAM). A method and the associated apparatus track such variations in an OFDM system and completely eliminate any performance degradation. Gain estimation and compensation is employed with the use ...

04/05/07 - 20070076807 - Enhanced uplink rate indicator
The claimed subject matter relates to providing uplink data rate option information in an uplink traffic channel segment. A wireless terminal may indicate a data rate option being used for the segment via an energy pattern applied to the tone-symbols of the segment. To indicate a first data rate option, ...

04/05/07 - 20070076806 - Interpolation module, interpolator and methods capable of recovering timing in a timing recovery apparatus
The invention relates to an interpolation module, an interpolator, and methods capable of recovering timing, and in particular, to an interpolation module, an interpolator, and methods capable of recovering timing in a timing recovery apparatus. An interpolation module capable of recovering timing in a timing recovery apparatus comprises a first ...

04/05/07 - 20070076805 - Multicarrier receiver for multiple-input multiple-output wireless communication systems and method
Embodiments of a multicarrier receiver and method for generating soft bits in a multiple-input multiple-output system are generally described herein. In some embodiments, operational parameters for an equalizer and a soft-bit demapper in a multicarrier receiver are determined. Other embodiments may be described and claimed. ...

04/05/07 - 20070076804 - Image-rejecting channel estimator, method of image-rejection channel estimating and an ofdm receiver employing the same
The present invention provides an image-rejecting channel estimator for use with an orthogonal frequency division multiplex (OFDM) receiver employing scattered pilot channel estimates. In one embodiment, the image-rejecting channel estimator includes an estimation interpolator configured to provide channel estimates through time interpolation and frequency interpolation employing the scattered pilot channel ...

03/29/07 - 20070071125 - Method and apparatus for ifdma transmission
Various embodiments are described to provide for the transmission of data in an improved manner. Data transmission is improved by including in a transmitter a null generator to embed frequency domain nulls into a data symbol sequence to produce a null-embedded data symbol sequence. A symbol inserter inserts a control ...

03/29/07 - 20070071124 - Multi-carrier communication apparatus, integrated circuit, multi-carrier communication system, and muti-carrier communication method
A digital transmission signal from a digital signal processing unit is converted to an analog signal in an analog circuit, and is transmitted from transmission lines via a communication transformer. The digital signal processing unit includes a time carrier detector that detects existence or non-existence of a carrier by using ...

03/29/07 - 20070071123 - Synchronization method, receiver, network element, communication device, electronic device, computer program product and computer program distribution medium
The invention is related to a synchronization method in a communication system. The invention includes: carrying out a coarse time offset and frequency offset estimation, first estimating errors in the coarse time-offset and frequency offset estimation by using a maximum-likelihood time-offset estimation and joint optimisation of time-offset and frequency-offset, second ...

03/29/07 - 20070071122 - Evaluation of transmitter performance
Systems and methodologies are described that facilitate monitoring transmitter performance in a wireless communication environment. A signal analyzer can be used to sample the output of a transmitter and the sampled signal can be propagated to a processor. The processor can generate frequency domain channel estimates for the subcarriers. If ...

03/29/07 - 20070071121 - Method and system for increasing data rate in a mobile terminal using spatial multiplexing for dvb-h communication
A method and system for increasing data rate in a mobile terminal using spatial multiplexing for digital video broadcasting for handhelds (DVB-H) communication are provided. A reconfigurable orthogonal frequency division multiplexing (OFDM) chip may be utilized in a mobile terminal to process received spatially multiplexed signals. The mobile terminal may ...

03/29/07 - 20070071120 - Peak to average power reduction using channel state information
Methods and systems for communicating in a wireless network include reducing the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) subcarriers based on channel state information. Reducing the PAPR may include observing channel state information such as channel impulse response, interference or noise of a receive channel, selecting ...

03/29/07 - 20070071119 - Multicarrier transmitter for multiple-input multiple-output communication systems and methods for puncturing bits for pilot tones
Embodiments of a transmitter and methods for puncturing bits are generally described herein. Other embodiments may be described and claimed. In some embodiments, a multicarrier transmitter performs bit puncturing for pilot subcarriers in two operations. The first operation may uniformly removes bits from an encoded bit stream to achieve a ...

03/29/07 - 20070071118 - Scalable system to adaptively transmit and receive including adaptive antenna signal and back-end processors
An adaptive baseband processing system having a scalable architecture to allow scaling to support adaptive transmission and receive, at different granularity, channel vs. subchannel, for different number of antennas and/or users, including their components, are described herein. In various embodiments, the components include a front-end processor, an AAS processor and ...

03/29/07 - 20070071117 - Communication method, transmission signal forming method, and data structure of transmission signal
In a communication method for transmitting a multipath characteristic measurement signal and a plurality of data transmission signals, the multipath characteristic measurement signal and data transmission signals are a signal array formed by a plurality of coefficient matrices that are orthogonal to one another within the matrices and which comprise ...

03/29/07 - 20070071116 - Spectrum coding apparatus, spectrum decoding apparatus, acoustic signal transmission apparatus, acoustic signal reception apparatus and methods thereof
A spectrum coding apparatus capable of performing coding at a low bit rate and with high quality is disclosed. This apparatus is provided with a section that performs the frequency transformation of a first signal and calculates a first spectrum, a section that converts the frequency of a second signal ...

03/29/07 - 20070071115 - Frequency combining apparatus and frequency combining method
A reference frequency of 4224 MHz is divided into ½ to obtain a sampling frequency of 2112 MHz, and further the frequency division into ½ is sequentially performed and the values of three bits outputted by the ½, ¼ and ⅛ frequency division are decoded in response to frequency selection. ...

03/22/07 - 20070064826 - Space-time trellis code for orthogonal frequency division multiplexing (ofdm)
A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that is configured to output a plurality of input signals. The transmitter also includes an encoder that is configured to generate a plurality of output signals in response ...

03/22/07 - 20070064825 - Communication device for receiving and transmitting ofdm signals in a wireless communication system
A communication device for receiving and transmitting OFDM signals in a wireless communication system, in which each OFDM signal is composed of a plurality of subcarrier signals each being assigned to a respective transmission channel of said communication system, including a diversity antenna unit including a plurality of antenna elements; ...

03/22/07 - 20070064824 - Hybrid domain block equalizer
The invention provides a method and device for iterative hybrid time-frequency domain block equalization of signals received via a communication channel subject to multipath interference. The equalization method includes frequency-domain equalization of blocks of received signals in a forward path, and time-domain inter-block echo correction and intra-block cyclic echo addition ...

03/22/07 - 20070064823 - Apparatus and method for calibrating channel in radio communication system using multiple antennas
Provided is an apparatus and method for calibrating a channel in a radio communication system using multiple antennas. A base station apparatus for the radio communication system includes a channel estimator and a calculator. The channel estimator receives a UL sounding signal to estimate a first UL CSI and receives ...

03/22/07 - 20070064822 - Radio apparatus
Among destination terminal apparatuses to which a plurality of data signals are to be transmitted, a control unit specifies a terminal apparatus to which a known signal, whose number of streams is greater than the number of streams for a data signal, is to be transmitted. The control unit appends ...

03/22/07 - 20070064821 - Memory reduction in digital broadcast receivers
An input random access memory (RAM) module of a fast Fourier transform (FFT) engine of a DVB receiver is used to store, during a first time period, delayed versions of an input signal that includes a first orthogonal frequency division multiplexed (OFDM) symbol and a cyclic prefix therefor received at ...

03/15/07 - 20070058744 - Linear transformation circuits
A transform circuit includes a first circuit and a second circuit. The first circuit and the second circuit implement first and second mappings that together generate a pre-defined transform of N digital data symbols. The first circuit maps a set of N digital data symbols from N parallel data streams ...

03/15/07 - 20070058743 - Ofdm communications system employing crest factor reduction with isi control
A system and method for providing a peak power reduced OFDM communications signal are disclosed. The system and method provide peak reduction processing in the time domain followed by inter-symbol interference (ISI) control processing in the frequency domain to maintain modulation errors introduced by the peak reduction processing to an ...

03/15/07 - 20070058742 - Distributed antenna system using signal precursors
A system and method for distributing multiple wireless carriers to transmission sites is disclosed. Carrier precursors are distributed which are digital in format and compressed in bandwidth. The individual carrier precursors are combined using time division multiplexing to eliminate the need for excess bandwidth allotments. A separate time division multiplexed ...

03/15/07 - 20070058741 - Demodulation apparatus and demodulation method
A demodulation apparatus includes a first demodulator for receiving a first received subcarrier and demodulating it by a first demodulation mode, a second demodulator for receiving a second received subcarrier and demodulating it by a second demodulation mode, a third demodulator for demodulating composite subcarriers obtained by combining the first ...

03/15/07 - 20070058740 - Likelihood corrector and likelihood correction method
In an orthogonal frequency division multiplexing system using a scattered pilot signal, after equalization and Fourier transformation of the received signal, the pilot signals are extracted and further processed to generate likelihood values. In one process, the transformed signal is multiplied by the reciprocal of a variance. In another process, ...

03/15/07 - 20070058739 - Automatic gain control for frequency-hopped ofdm
An automatic gain control method and system for use in signal processing of OFDM symbols at a receiver. Two stages of coarse and fine automatic gain control are implemented that adjust different gains in an analog RF processing stage of the receiver. Gain of a low noise amplifier and a ...

03/15/07 - 20070058738 - Overlap-and-add with dc-offset correction
A method and system for estimating DC offset and removing the excess DC offset from samples used by an overlap-and-add operation at the receiver of OFDM symbols in UWB communication. The DC offset for each sample within the overlap-and-add interval may be estimated using a sliding window, of the size ...

03/15/07 - 20070058737 - Convolutive blind source separation using relative optimization
A method and apparatus for separating a multi-channel mixed signal are provided. The method includes the steps of: a) transforming a temporal domain to a frequency domain by performing a discrete Fourier transform onto at least one of mixed signals inputted from an external device through multi-channel; b) estimating multi-decorrelation ...

03/15/07 - 20070058736 - Ultra wideband baseband chip with intelligent array radio and method of use thereof
An ultra wideband receiver combines digital data from multiple channels after signal processing and before decoding and provides a master controller that combines control signals from multiple channels to control the receiver. ...

03/15/07 - 20070058735 - Method and apparatus for equalizing signals
A system and apparatus are disclosed for a method and apparatus for equalizing signals. An apparatus that incorporates teachings of the present disclosure may include, for example, an equalizer (100) having a channel estimation calculator (102) for calculating a time domain channel estimation from a baseband signal, an FFT processor ...

03/15/07 - 20070058734 - Circuit for improving channel impulse response estimation and compensating for remnant frequency offset in the orthogonal frequency division multiplexing baseband receiver for ieee 802.11a/g wireless lan standard standard
A circuit for improving accuracy of channel impulse response estimation and compensating for remnant frequency offset in a receiver of an orthogonal frequency division multiplexing (OFDM) system is provided. The circuit comprises an equalizer, for compensating a first signal for channel distortion with the channel impulse response estimate to generate ...

03/15/07 - 20070058733 - Method of demodulating ofdm type signals in the presence of strong co-channel interference signals
Method of demodulating a signal in a transmission system where the modulation includes several substantially orthogonal subcarriers, the vector of the propagation channel H[n,k] being known, or the received signal including at least pilot symbols emitting reference data. It comprises at least one step of estimating the symbol a[n,k] emitted ...

03/08/07 - 20070053459 - System and method for obtaining accurate symbol rate and carrier phase, frequency, and timing acquisition for minimum shift keyed waveform
The present invention relates generally to communication systems, both wired and wireless, employing a continuous phase modulation (“CPM”) waveform with a minimum shift keying (“MSK”) preamble. The present inventive system and method uses information from contiguous Fourier Transforms taken on contiguous data blocks to determine baud rate, phase, frequency offset, ...

03/08/07 - 20070053458 - Multi-tone transmission
A Multi-tone transmission system processes input data through a plurality of intermediate processing stages 12, 14, 16 and corresponding stages of intermediate data 18,20. A symbol including a number of tones is obtained therefrom by an inverse Fourier transform 24 and stored in a buffer 158. The peak amplitude that ...

03/08/07 - 20070053457 - Signal component demultiplexing apparatus, filter apparatus, receiving apparatus, communication apparatus, and communication method
A communication apparatus, a signal component demultiplexing apparatus, and a filter apparatus to reduce a load of FFT processing in a receiver in multi-carrier communication. The receiving apparatus provides a signal component demultiplexing apparatus before an FFT circuit and extracts only the required symbol series. The signal component demultiplexing apparatus ...

03/08/07 - 20070053456 - Method for allocating sub-channel in a mobile communication system using orthogonal frequency division multiple access scheme
A method is provided for allocating sub-channels in an Orthogonal Frequency Division Multiple Access (OFDMA) mobile communication system including a plurality of cells or a plurality of sectors. The method comprises dividing a time interval preset into a band Adaptive Modulation and Coding (AMC) sub-channel region and a diversity sub-channel ...

03/08/07 - 20070053455 - Signal processing system and method for calibrating channel signals supplied from an array of sensors having different operating characteristics
In a signal processing system, a set of channel signals from an array of sensors of different operating characteristics are processed in calibration circuitry that calculates individual average values of the channel signals and calculates an average of the individual average values of channel signals as a reference value. Reciprocal ...

03/08/07 - 20070053454 - Compensation method and apparatus in orthogonal frequency division multiplexing (ofdm) systems
In estimating and compensating impairments of Orthogonal Frequency Division Multiplexing (OFDM) symbols, a first estimation is obtained by evaluating and comparing received training symbols with transmitted training symbols. A second estimation is obtained by evaluating and comparing a first portion of received payload symbols with estimated payload symbols. A final ...

03/08/07 - 20070053453 - Low noise inter-symbol and inter-carrier interference cancellation for multi-carrier modulation receivers
A MCM (multi-carrier modulation) receiver that utilizes a plurality sub-carriers (e.g., tones) to transmit information in a frame-by-frame manner. Identify a first subset of sub-carriers that have negligible ISI (inter-symbol interference) and ICI (inter-carrier interference), and a second subset of sub-carriers that ISI/ICI cancellation is needed to improve the performance. ...

03/08/07 - 20070053452 - Method and apparatus for estimating signal-to-noise ratio, noise power, and signal power
In a wireless communication system, a method and apparatus for noise estimation of a received OFDM communication signal, wherein the signal comprises a data frame with a preamble having at least one long training field (LTF) containing two substantially similar OFDM symbols, comprise examining the LTF for substantially similar OFDM ...

03/08/07 - 20070053451 - Digital automatic gain control with parallel/serial interface for multiple antenna ultra wideband ofdm system
The invention enables automatic gain control in ultra wideband applications over multiple channels and frequency bands. ...

03/08/07 - 20070053450 - Technique for providing secondary data in a single-frequency network
A technique for providing secondary data in a single frequency network (SFN) provides a first forward error correcting (FEC) decoder for decoding a received coded orthogonal frequency division multiplex (COFDM) signal. A second FEC decoder is also provided for decoding a received COFDM signal. When the received COFDM signal includes ...

03/08/07 - 20070053449 - Transmitter apparatus, communication system, and communication method
A communication technology for allowing a mobile communication system to accommodate variable rate users, while obtaining a frequency diversity effect. A transmitter apparatus using, for transmission, transmission signals produced based on data symbols of a predetermined transmission method, comprising an FFT processing part for converting the data symbols to frequency ...

03/08/07 - 20070053448 - Method, system and receiver in receiving a multi-carrier transmission
Mobile handheld terminals receiving DVB transmission require relatively low power consumption and TDM based transmission can be used to reduce power of the terminals. In order find pilot carrier position at least two symbols are accessed which are adapted to establish a correspondence pattern for pilot carriers in a matrix ...

03/01/07 - 20070047665 - Methods and systems for communicating signals through multi-carrier systems
Methods and systems for communicating a signal through a multi carrier system session are disclosed. The carrier channel includes a plurality of subcarriers. A bit value for each subcarrier of the plurality of subcarriers is determined (202, 402) based on the signal to be communicated. The plurality of subcarriers is ...

02/22/07 - 20070041460 - Wireless communication apparatus using fast fourier transforms to create, optimize and incorporate a beam space antenna array in an orthogonal frequency division multiplexing receiver
A wireless communication apparatus which uses fast Fourier transforms (FFTs) in an orthogonal frequency division multiplexing (OFDM) receiver which incorporates a beam space antenna array. The beam space antenna array may be implemented with a Butler matrix array. The beam space antenna array may be a circular array, vertical array, ...

02/22/07 - 20070041459 - Apparatus and method for reducing peak-to-average power ratio in an ofdm communication system
A Peak-to-Average Power Ratio (PAPR) reduction apparatus and method in an OFDM communication system are provided. In the PAPR reduction method, magnitude and phase components are extracted from transmission sample data. Peaks having magnitude components exceeding a threshold are detected by comparing the extracted magnitude components with the threshold. The ...

02/22/07 - 20070041458 - Encoding for digital communications in a multiple-input, multiple-output environment
Transceiver circuitry for use in a multiple-input, multiple-output (MIMO), orthogonal frequency-division multiplexing (OFDM), communications environment, is disclosed. Error correction coding according to a fixed-block size code, such as low density parity check (LDPC) coding, is implemented. The codeword length, and codeword arrangement, are selected by determining a minimum number of ...

02/22/07 - 20070041457 - Method and apparatus for providing antenna diversity in a wireless communication system
Transmission schemes that can flexibly achieve the desired spatial multiplexing order, spatial diversity order, and channel estimation overhead order are described. For data transmission, the assigned subcarriers and spatial multiplexing order (M) for a receiver are determined, where M≧1. For each assigned subcarrier, M virtual antennas are selected from among ...

02/22/07 - 20070041456 - Method and device for estimating a multicarrier signal propagation channel
A method is provided for estimating a propagation channel composed of successive symbols of a multicarrier signal, each comprising at least one reference pilot and a plurality of data-carrying frequencies. Such a method comprises, in particular, at least one step consisting of correcting the at least one reference pilot on ...

02/15/07 - 20070036235 - Transmitting apparatus and method for a digital telecommunication system
The present invention relates to a receiving apparatus (1) for receiving signals in a digital telecommunication system and a synchronising method for synchronising such a receiving apparatus (1). The receiving apparatus (1) comprises receiving means (2, 3) for receiving a reference symbol comprising at least two repetition patterns, whereby one ...

02/15/07 - 20070036234 - Orthogonal frequency division multiplexing system with pn-sequence
The invention relates to an orthogonal frequency division multiplexing system with PN-sequence. In the synchronization of the invention, both timing offset and frequency offset are estimated and compensated by utilizing a time and frequency synchronization device. In addition, the PN-sequence with the cyclic prefix is added to the OFDM symbol ...

02/15/07 - 20070036233 - Sampling of data streams and supporting methods and apparatus
In the present sampling technique of a transmitted data stream, a data stream is divided (318, 504) into a predefined number of sample streams to provide a plurality of sample streams, and for at least two of these sample streams, a metric value is assessed (324, 514, 516) and compared ...

02/15/07 - 20070036232 - Ofdm reception apparatus and ofdm reception method
Precision of channel estimation is improved. An OFDM reception apparatus for receiving and demodulating an OFDM signal which transmits a pilot signal, comprises a channel estimation section for calculating a channel response before interpolation by performing computation between a frequency-domain OFDM signall and the pilot signal, performing interpolation with respect ...

02/15/07 - 20070036231 - Demodulation device and demodulation method
The present invention relates to a demodulation device and a demodulation method, and its object is to demodulate subcarrier components utilizing estimated delay profiles to control the timing for performing a Fourier transform and the pass band of an interpolation filter used in interpolating transmission channel characteristics along a frequency ...

02/08/07 - 20070030914 - Method and system for channel estimation and interference cancellation in an orthogonal frequency division multiple access network
A method of channel estimation and interference cancellation in an Orthogonal Frequency Division Multiple Access network is provided. The method includes determining an estimate of a transmitted signal based on an initial channel estimate and a received signal. An extracted transmitted signal is generated based on the estimate of the ...

02/08/07 - 20070030913 - Orthogonal frequency division multiplexing receiver capable of canceling impulse interference
An orthogonal frequency-division multiplexing (OFDM) receiver that has a capability for canceling impulse interference is introduced in the present invention. The OFDM receiver includes an impulse noise remover for receiving incoming signals and canceling the impulse interference and a demodulator to demodulate the incoming signals. The impulse noise remover includes ...

02/01/07 - 20070025462 - Data transmission method, data reception method, data transport method, data transmission apparatus, data reception apparatus and data transport system as well as communication terminal
On a transmitting side, input data is separated into a first data row and a second data row by the unit of predetermined symbol; one code is selected among a plurality of orthogonal codes in accordance with the separated second data row; the first data row is diffused using the ...

02/01/07 - 20070025461 - Phase noise compensation apparatus and an ofdm system having the apparatus and method thereof
Disclosed is a phase noise compensation apparatus to be applied to the OFDM system, comprising an ICI estimating unit for estimating inter carrier interference (ICI) using a pilot sub-carrier included in a reception signal, a estimating unit for estimating a common phase error (CPE), which is a phase noise from ...

02/01/07 - 20070025460 - Simplified channel and interference estimation with dedicated pilot tones for ofdma
Estimation of channel characteristics and interference level in a time-varying multi-carrier multi-user systems is carried out concurrently. To perform the estimation, a multitude of data symbols and dedicated pilot symbols are transmitted over the channel. The estimate of the interference level is used to estimate the channel parameters. ...

02/01/07 - 20070025459 - Method for transmitting user data in a multi-carrier radio communication system, and corresponding receiver
The present invention relates to a method for transmitting user data between a transmitter and a receiver in a multi-carrier radio communication system having a plurality of orthogonal frequency sub-carriers, said method comprising the steps of selecting a set of sub-carriers on which said user data are to be transmitted ...

02/01/07 - 20070025458 - Transmitter for transmitting user data in a multi-carrier radio communication system, corresponding method
The present invention relates to a transmitter for transmitting user data between a transmitter and a receiver in a multi-carrier radio communication system having a plurality of orthogonal frequency sub-carriers, said method comprising the steps of selecting a set of sub-carriers on which said user data are to be transmitted ...

02/01/07 - 20070025457 - Synchronization method and apparatus for ofdm systems
A synchronization apparatus and method for an OFDM system includes four portions: delay conjugate multiplication, phase processing, delay moving sum and minimum value detection. The invention performs the correlation phase operation and finds out the location of abnormal change for the phase difference of the output signal. The location is ...

02/01/07 - 20070025456 - Methods and apparatus for encoding information in a signal by spectral notch modulation
A spectral notch modulation technique for encoding information in a signal involves transforming the signal into the frequency domain via a fast Fourier transform (FFT) of length N, such that the signal is represented by N frequency bins, selectively nulling M of the N frequency bins, where nulled combinations of ...

02/01/07 - 20070025455 - Method and apparatus for reducing transmitter peak power requirements with orthogonal code noise shaping
A method and apparatus for reducing peak transmitter power includes providing a set of orthogonal communication codes for a telecommunications system that includes a set of active user codes and a set of inactive user codes (1404). A communication signal is generated from the set of active user codes (1406). ...

02/01/07 - 20070025454 - Interference mitigation for orthogonal frequency division multiplexing communication
An Orthogonal Frequency Division Multiplex (OFDM) communication system comprises OFDM transmitters (103-109) and an OFDM receiver (101). The system comprises a subcarrier status data controller (200) for transmitting subcarrier status data to the OFDM receiver (101). The subcarrier status data indicates the active subcarriers of the OFDM transmitters (103-109). The ...

01/25/07 - 20070019755 - Method for seamlessly changing power modes in an adsl system
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation The. DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

01/25/07 - 20070019754 - Spatio-temporal processing for communication
A space-time signal processing system with advantageously reduced complexity. The system may take advantage of multiple transmitter antenna elements and/or multiple receiver antenna elements, or multiple polarizations of a single transmitter antenna element and/or single receiver antenna element. The system is not restricted to wireless contexts and may exploit any ...

01/25/07 - 20070019753 - Adaptive multilevel block coded modulation for ofdm systems
A method includes grouping a data stream into a first plurality of subgroups, modulating a plurality of subcarriers with the first plurality of subgroups, adaptively applying a block code to said data stream comprising a repetition code, a Hamming code, and a plurality of uncoded bits based upon a channel ...

01/25/07 - 20070019752 - Decoders using fixed noise variance and methods of using the same
Decoders are provided including a data input unit configured to receive and store data. A noise variance judging unit is configured to select a fixed noise variance from a lookup table including at least one predetermined fixed noise variance. A log-likelihood ratio (LLR) calculating unit is configured to calculate an ...

01/25/07 - 20070019751 - Block oriented digital communication system and method
A method and system for estimating a time shift required for symbol synchronization in a block oriented digital communication systems such as an orthogonal frequency division multiplexing (OFDM) or a discrete multi-tone (DMT) data transmission system. The method uses an N/d inverse discrete Fourier transform (IDFT), where N is a ...

01/25/07 - 20070019750 - Mimo timing recovery
Multiple-input-multiple-output (MIMO) timing recovery. A novel approach is presented to perform timing recovery when processing the multiple received signals within a MIMO communication device. This may be implemented for a singular received signal, or a plurality of received signal streams. In addition, this timing recovery may be performed in conjunction ...

01/25/07 - 20070019749 - Carrier detection applicable for siso, mimo, miso, and simo communications
Carrier detection applicable for SISO, MIMO, MISO, and SIMO communications. A novel approach is presented to perform carrier detection for a signal found in any of a wide variety of communication systems including single-input-multiple-output (SISO), multiple-input-multiple-output (MIMO), multiple-input-single-output (MISO) single-input-multiple-output (SIMO), communication systems. This novel approach to performing carrier detection ...

01/25/07 - 20070019748 - Angle estimation for modulated signal
Angle estimation for modulated signal. A novel compensation technique is presented by which angle estimation may be performed for a modulated signal. More specifically, the angle between a constellation corresponding to a received signal and a constellation corresponding to a received signal may be very efficiently estimated using any one ...

01/25/07 - 20070019747 - Method and apparatus for interleaving in a wireless communication system
The method and apparatus in accordance with the present invention receives bits, writes the bits row-by-row in a matrix, reads the bits column-by-column from the matrix, groups and rotates the bits read column-by-column from the matrix so as to evenly separate the bits in position, frequency, space over one symbol ...

01/25/07 - 20070019746 - Inter-symbol and inter-carrier interference canceller for multi-carrier modulation receivers
A MCM (multi-carrier modulation) receiver that utilizes a plurality tones to transmit information. Identify a first subset of tones that have negligible ISI (inter-symbol interference) and ICI (inter-carrier interference), and a second subset of tones that ISI/ICI cancellation is needed to improve the performance. For tones in the first subset, ...

01/18/07 - 20070014376 - Method and system for optimization of channel estimation and synchronization in an ofdm-mimo wireless communication system
The present invention is related to a method and system for optimization of channel estimation and synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) Multiple-Input Multiple-Output (MIMO) wireless communication system. In accordance with the present invention, all of the training sequences are simply constructed based on a basic code by ...

01/18/07 - 20070014375 - Radio apparatus
A modem unit inputs a combination, of control signal and data signal, which is to use a plurality of subcarriers. Among a plurality of combinations inputted, the modem unit performs interleaving with a size defined by the first number of subcarriers on a control signal and performs interleaving with the ...

01/11/07 - 20070009056 - Method and apparatus for transmitting a signal in a communication system
A method and apparatus for processing time windowing to transmit a signal in a Broadband Wireless Access (BWA) communication system based on Orthogonal Frequency Division Multiple Access (OFDMA). A signal of a first interval included in a previous symbol prior to a current symbol is stored as a signal of ...

01/11/07 - 20070009055 - Multicarrier communication apparatus, integrated circuit, and multicarrier communication method
A digital transmission signal from a digital signal processing unit is converted to an analog signal in an analog circuit, and is transmitted from transmission lines via a communication transformer. The digital signal processing unit includes a time carrier detector that detects a carrier by using a time waveform of ...

01/11/07 - 20070009054 - Method and transmission apparatus for allocating resources to transmit uplink packet data in an orthogonal frequency division multiplexing system
Provided is a resource allocation method that considers frequency scheduling gain and frequency diversity gain when uplink packet data is transmitted in a wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM). A method is provided in which Localized Frequency Division Multiple Access (LFDMA) technology capable of obtaining the ...

01/11/07 - 20070009053 - Base station methods and apparatus for dc tone special treatment
Special DC tone treatment in a wireless communications system, e.g., an OFDM system, is discussed. In the downlink, a wireless terminal receiver introduces self-interference at the DC tone from the RF/baseband conversion. A base station every so often does not transmit on the downlink DC tone while continuing to transmit ...

01/04/07 - 20070002959 - Apparatus and method for detecting user in a communication system
Disclosed is a method for detecting a user in a communication system. The method includes selecting i ranging sub-carrier signals among k sub-carrier signals upon which a k-point fast Fourier transform (FFT), has been performed multiplying the i ranging sub-carrier signals by a ranging code, performing k-point inverse fast Fourier ...

01/04/07 - 20070002958 - Apparatus and method for configuring frame in a broadband wireless communication system
There is provided a transmitting apparatus in a broadband wireless communication system in which a control channel generator generates a control channel that includes an user information and a resource group information allocated to the user based on position and number of at least one predetermined resource unit included in ...

01/04/07 - 20070002957 - Modem using error coding in accordance with scale of demodulation spectral transform
A communication apparatus includes a scalable N-point spectral transform block coupled to provide a transformed signal from a discrete multi-tone (DMT) modulated signal carrying digital data. A convolutional decoder is coupled to receive the transformed signal. The convolutional decoder is enabled only if N is less than a first pre-determined ...

01/04/07 - 20070002956 - Modem with scalable spectral transform for demodulation
A communications apparatus includes a modem coupled to receive digital data as a discrete multi-tone (DMT) modulated signal. The modem scales the N-point spectral transform for demodulation in accordance with at least one of a channel-width, a number of sub-channels, and a bit-rate of the channel. If the chosen metric ...

01/04/07 - 20070002955 - Weighting circuit for a multi-carrier signal receiver
The invention relates to a weighting circuit for a receiver (1), which is designed to receive a multi-carrier signal consisting of carrier signals. According to the invention, the carrier signals are weighted by the weighting circuit (18) in such a way that the parasitic signal energy has the same intensity ...

12/28/06 - 20060291578 - Method and apparatus for multicarrier channel estimation and synchronization using pilot sequences
Method and apparatus for OFDM synchronization and channel estimation. In a temporal embodiment, received embedded system pilot symbols are inverse Fourier transformed at expected index locations and correlated with computed complex conjugates of inverse Fourier transforms of pilot symbols for providing a correlation function for the channel impulse response. In ...

12/28/06 - 20060291577 - System and method for selecting pilot tone positions in communication systems
A system and method for selecting pilot tone positions in a communication system. In one embodiment, the communication system includes a first base station configured to generate a first pattern of positions of pilot tones and a second base station configured to generate a second pattern of positions of pilot ...

12/28/06 - 20060291576 - Method and system for optimal bitloading in communication and data compression systems
This invention provides a method and system for determining the number of bits to assign to a frequency range in a signal. The present invention is capable of bit allocation, with B total bits, among a plurality of N frequency ranges in time a time O(N log N), which is ...

12/21/06 - 20060285602 - Method of transmitting/receiving ofdm signal and mobile communication terminal thereof
A method of transmitting/receiving an OFDM signal and mobile communication terminal thereof are disclosed, by which high PAPR (peak to average power ratio) can be efficiently reduced in an OFDM transmission system. The present invention includes the steps of converting a bit stream data signal to parallel from serial, block-coding ...

12/21/06 - 20060285601 - Ofdma control channel interlacing
Apparatus and methods for interlacing communications in random access control channels of an Orthogonal Frequency Division Multiple Access (OFDMA) wireless communication system are described. A wireless communication device communicating over distinct OFDMA control channels to multiple serving sectors may operate under link limited conditions. The wireless communication device can interlace ...

12/21/06 - 20060285600 - Ofdm channel estimator
The channel estimation technique employs a set of pilot tones to determine channel state information. Because some of the pilot tones contained in the OFDM symbols may be missing after transmission, the disclosed technique employs a set of known pilot tones to compute an estimate of the channel impulse response, ...

12/21/06 - 20060285599 - Receiver for orthogonal frequency division multiplexing transmission
Channel estimation values of pilot symbols for channel compensation of data symbols in an OFDM receiver can be used, even in cases where FFT extract position differs for each frame. The OFDM receiver is characterized in having a circuit which calculates the amount of phase rotation that is generated by ...

12/14/06 - 20060280256 - Method, apparatus, and system for transmitting and receiving information of an uncoded channel in an orthogonal frequency division multiplexing system
A method, apparatus and system for efficiently transmitting and receiving channels are provided in a wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM). A multiplexing scheme differs according to a channel when a transmitter transmits a packet data channel, a common control channel and a control channel designated ...

12/14/06 - 20060280255 - System, and associated method, for utilizing block blast with ppic in a mimo multicode mc-cdma system
A method for reducing interference in a MIMO MultiCode MC-CDMA system is disclosed wherein a BLAST algorithm is implemented over one block of correlation reception data yi and estimation channel values H of the correlation reception data yi to generate a group of temporary decision symbols C . One symbol, ...

12/07/06 - 20060274844 - Frequency-independent spatial processing for wideband miso and mimo systems
Frequency-independent eigensteering in MISO and MIMO systems are described. For principal mode and multi-mode eigensteering, a correlation matrix is computed for a MIMO channel based on channel response matrices and decomposed to obtain NS frequency-independent steering vectors for NS spatial channels of the MIMO channel. ND data symbol streams are ...

12/07/06 - 20060274843 - Apparatus and method for transmitting/receiving preamble signal in a wireless communication system
An apparatus and method for transmitting/receiving a multi-functional preamble signal in a wireless communication system are provided. In an apparatus for transmitting a preamble signal in a wireless communication system, a first generator generates a predetermined ZAC sequence. A circular shifter circular-shifts the ZAC sequence according to a BS ID. ...

12/07/06 - 20060274842 - Frequency domain joint detection for wireless communication systems
A method and apparatus for frequency domain joint detection for multicarrier code division multiple access (MC-CDMA) and spread orthogonal frequency division multiple access (OFDMA) systems are disclosed. The apparatus includes a receiver having a frequency domain joint detector, whereby channel distortion and data symbols are jointly equalized and detected by ...

12/07/06 - 20060274841 - System and/or method for channel estimation in communication systems
Embodiments of methods, devices and/or systems for estimating channel state information are described. ...

12/07/06 - 20060274840 - Method for seamlessly changing power modes in an adsl system
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

12/07/06 - 20060274839 - Method and system for adaptive control of sub-carriers
A method and system for adaptive control of sub-carriers is useful for increasing frequency diversity gain to improve bit error rate performance in an Interleaved Frequency Division Multiple Access (IFDMA) system. The method includes selecting a combination of a Repetition Factor (RF) and a repetition block size (Q), from possible ...

11/30/06 - 20060269009 - Transmission schemes for multi-antenna communication systems utilizing multi-carrier modulation
Pilot and data transmission schemes for multi-antenna communication systems utilizing multi-carrier modulation are provided. Subband multiplexing is used to avoid interference resulting from transmitting multiple signals simultaneously from multiple antennas. M usable subbands are initially arranged to form multiple groups of subbands, with each group including a different subset of ...

11/30/06 - 20060269008 - Receiving apparatus and synchronising method for a digital telecommunication system
A receiving apparatus (1) for receiving signals in a digital telecommunication system and a synchronizing method for synchronizing the receiving apparatus (1). The receiving apparatus (1) includes a receiver (2, 3) for receiving a reference symbol having at least two repetition patterns. One of the, repetition patterns is phase-shifted in ...

11/30/06 - 20060269007 - Cyclic training sequence generating method, communication system and communication method
A method for generating a cyclic training sequence and a communication method and system using the cyclic training sequence are disclosed. The cyclic training sequence includes a first training symbol and a second training symbol sequentially, the first training symbol including a first CP and a first information block sequentially ...

11/30/06 - 20060269006 - Wireless communication apparatus and wireless communication method
A wireless communication apparatus for receiving spatially multiplexed signals in which a plurality of streams are spatially multiplexed, using a plurality of antennas, includes the following elements: a channel matrix estimator for estimating a channel matrix for multiplexed channels; a spatial decoder for spatially decoding received signals each of which ...

11/30/06 - 20060269005 - Methods and apparatus for combining and/or transmitting multiple symbol streams
A stream of modulation symbols from a zero symbol rate (ZSR) coding/modulation module and a stream of modulation symbols from another type of coding/modulation module are input into an interweaver module. The interweaver module mixes the two input streams when assigning modulation symbols to be communicated in a segment. If ...

11/30/06 - 20060269004 - Method and system for digital spur cancellation
A method and system for digital spur cancellation may include removing a spur in a left channel minus right channel (L−R) baseband signal generated from a FM signal. The L−R baseband signal may be generated by demodulating a sub-carrier, for example, by using CORDIC algorithm, in a signal demodulated from ...

11/30/06 - 20060269003 - Method and apparatus for frequency domain compensation of dc offset in an orthogonal frequency division multiplexing system
Methods and systems are provided for estimating the DC offset distortion in a receiver. A fast Fourier transform is applied to at least a portion of a preamble portion of the received signal; an impact of the DC offset distortion on one or more empty subcarriers is determined; individual DC ...

11/23/06 - 20060262872 - Vector calibration system
Among other things, calibration of a signal processing system is disclosed to minimize vector mismatch between signals frequency-translated from an RF signal and conveyed along a plurality of signal paths of the signal processing system. A calibration signal having a plurality of tones is coupled to the signal processing system ...

11/23/06 - 20060262871 - Method and apparatus for multiplexing data and control information in wireless communication systems based on frequency division multiple access
An apparatus for transmitting data in a frequency division multiple access based communication system is disclosed. The apparatus includes a symbol block generator for generating a symbol block in a predetermined symbol block period within one TTI when control information to be transmitted exists in the TTI, an FFT unit ...

11/23/06 - 20060262870 - Apparatus and method for ft pre-coding of data and control signals to reduce papr in a multi-carrier wireless network
A subscriber station is provided for use in a wireless network communicating according to a multi-carrier protocol, such as OFDM or OFDMA. The subscriber station comprises: a size M1 Fourier Transform (FT) block that receives input symbols and generates M1 FT pre-coded outputs; a size M2 Fourier Transform (FT) block ...

11/23/06 - 20060262869 - Ofdm receiving method and receiving apparatus
Disclosed is an OFDM receiving apparatus for receiving a signal that has sustained inter-symbol interference owing to a delayed wave that exceeds a guard interval, eliminating at least inter-symbol interference from the receive signal and applying demodulation and decoding processing to the receive signal from which interference has been eliminated. ...

11/23/06 - 20060262868 - Phase noise compensation for mimo wlan systems
The present invention provides a method for reducing phase noise in OFDM systems by analyzing a time-dependent representation of the phase noise that changes in real time according to received data. The analysis of real time signals is based on processing statistical properties of phase noise and received data. The ...

11/16/06 - 20060256887 - Method and apparatus for indexing physical channels in an ofdma system
A method and system for indexing physical channels in an OFDMA system where one OFDM symbol includes a plurality of subcarriers and one TTI includes a plurality of OFDM symbols are provided. A total number of subcarriers per OFDM symbol are divided into N groups. A kth group is selected ...

11/16/06 - 20060256886 - Space-time block coding system combined with local polynomial approximation based beamformer
Provided is an STBC transceiving system with LPA-based beamformer, including: an STBC encoder having branches, in number of D, to generate output signals in number of D for an input signal; a beamformer having output antennas in number of D*B, being comprised of beam-forming subarrays in number of D each ...

11/16/06 - 20060256885 - Apparatus and method for estimating carrier-to-interference-and-noise ratio in an orthogonal frequency division multiplexing system
An apparatus and method for estimating a carrier-to-interference-and-noise ratio (CINR) of a received signal in an orthogonal frequency division multiplexing (OFDM) system are provided. A band-pass filter attenuates a signal region of the received signal and passes a signal in a noise region. A first power calculator calculates interference and ...

11/16/06 - 20060256884 - Radio receiver and radio receiving method
According to an aspect of the present invention, there is provided with a radio receiver including: one or more antenna which receives radio signals; a plurality of filters which selectively output signals in respective reception bands from the radio signals received by the antenna, adjacent reception bands partially overlapping each ...

11/16/06 - 20060256883 - Generating signals for transmission of information
A method and system for transmitting signals between communication nodes is presented. The method includes generating a first waveform that includes a shaped portion; generating a second waveform that includes a shaped portion; and combining the first and second waveforms including overlapping the shaped portion of the first waveform with ...

11/16/06 - 20060256882 - Method and apparatus for adjusting transmission parameters to improve a communication link
A method and apparatus is disclosed for minimizing multipath interference in wireless communication systems. A system comprises at least one transmitter and at least one receiver. In the transmitter, transmission beam parameters are dynamically modified using pseudo-random dithering or a sweeping function. The receiver receives an information signal regarding beam ...

11/16/06 - 20060256881 - Generating signals for transmission of information
A method for generating a signal is presented. The method includes selecting a first set of carrier frequencies that are integral multiples of a first frequency interval, and selecting a second set of carrier frequencies that are integral multiples of a second frequency interval. The second frequency interval is an ...

11/09/06 - 20060251180 - Method and system for selecting mcs in a communication network
A method for selecting an MCS for a carrier channel is provided. The method includes obtaining a set of characteristic parameters for a first function representing a variation of an effective SINR of the carrier channel with a calibration parameter; obtaining at least one of the effective SINR for a ...

11/02/06 - 20060245511 - Fractional bit rate encoding in a discrete multi-tone communication system
Fractional bit rate encoding in a discrete multi-tone (DMT) communication environment allows the transmission of fractional bit rates, thus maximizing the use of signal-to-noise ratio (SNR) available on each of the DMT carriers, or tones, while maintaining a constant power density over the entire frequency spectrum. ...

11/02/06 - 20060245510 - Radio communication system, radio communication apparatus, receiving apparatus, and radio communication method
A radio communication system, a radio communication apparatus, receiving apparatus and radio communication method are provided herein. The radio communication system may include a transmitting Unit which includes a mapping circuit which generates a data channel which has a known value inserted in idle subcarriers, a transmitter which transmits a ...

11/02/06 - 20060245509 - Method and system for processing mimo pilot signals in an orthogonal frequency division multiplexing network
A method of processing multiple-input/multiple-output pilot signals in an Orthogonal Frequency Division Multiplexing network is provided. The method includes, for each of a plurality of transmit antennas in a transmit antenna array, generating a processed pilot signal using a gain unique to the transmit antenna and transmitting the processed pilot ...

10/26/06 - 20060239370 - Time and frequency synchronization in multi-input, multi-output (mimo) systems
In a communication system, and in particular a wireless Orthogonal Frequency Division Multiplexing (OFDM) communication system, the present invention provides systems for synchronizing data transmitted across a channel. The present invention may be used in a Multi-Input, Multi-Output (IMO) system in which the data is transmitted from any number of ...

10/26/06 - 20060239369 - Methods and systems for transmission channel drlrction in wireless communication
A channel selection method applied at wireless communication. A transmitter selects a first transmission channel to carry test pattern. A receiver receives and compares the test pattern with stored data, and calculates a first signal quality. When the first signal quality exceeds a target value, the receiver sets the first ...

10/26/06 - 20060239368 - Apparatus and method for estimating frequency offset in orthogonal frequency division multiplexing system
An apparatus and method for estimating a frequency offset in an Orthogonal Frequency Division Multiplexing (OFDM) system are provided. Two time domain signals are generated from one received OFDM symbol through two observation windows with different delay times. The two time domain signals are compensated for a candidate frequency offset. ...

10/26/06 - 20060239367 - Low complexity inter-carrier interference cancellation
Inter-carrier interference (ICI) in a kth sub-carrier of an orthogonal frequency division multiplexing (OFDM) signal received at time t is reduced, wherein the received OFDM signal comprises a plurality of sub-carriers. This is achieved by generating a self-interference term, ICIk−L,k−L, for a signal received on sub-carrier k−L, wherein L ε ...

10/26/06 - 20060239366 - Rf transceiver having adaptive modulation
A modulation control module for use in an RF transceiver, the modulation control module includes a processing module and memory. The memory is operably coupled to the processing module, wherein the memory stores operational instructions that causes the processing module to: receive a multiple path channel estimation; and determining, for ...

10/26/06 - 20060239365 - Method and system for hierarchical modulation and demodulation for digital radio
A communication system (10) using hierarchical modulation includes at least one satellite (12 & 13) transmitting a data stream and a hierarchical modulated data stream, and at least one terrestrial station (16) transmitting the data stream and the hierarchical modulated data stream. The communication system can further include at least ...

10/26/06 - 20060239364 - Doppler spread estimation for ofdm systems
A Doppler spread value of a channel in an Orthogonal Frequency Division Multiplexing (OFDM) system is estimated, wherein the channel comprises a plurality of carrier frequencies. Estimating involves selecting a set of two or more carrier frequencies from the plurality of carrier frequencies. A Doppler spread value is estimated for ...

10/19/06 - 20060233273 - Multicarrier transmission system with low power sleep mode and rapid-on capability
A muticarrier transceiver is provided with a sleep mode in which it idles with reduced power consumption when it is not needed to transmit or receive data. The full transmission and reception capabilities of the transceiver are quickly restored when needed, without requiring the full (and time-consuming) initialization commonly needed ...

10/19/06 - 20060233272 - Feedback and scheduling schemes for a communications system
The present invention provides a transmitter. In one embodiment, the transmitter includes a coefficient circuit configured to generate coefficients of a set of basis waveforms that represent channel quality metrics and a transmit circuit that transmits the coefficients. The present invention also provides a receiver. In one embodiment, the receiver ...

10/19/06 - 20060233271 - Method and apparatus for channel estimation in distributed transmit diversity systems
A distributed transmit diversity system based on OFDM signaling transmits a broadcast/multicast service signal from one or more first base stations and from one or more second base stations, wherein the first and second base stations transmit orthogonalized pilots. Correspondingly, a remote receiver, e.g., a mobile station, resolves the orthogonal ...

10/19/06 - 20060233270 - Method and apparatus for uplink carrier frequency synchronization and antenna weight vector estimation in ofdma system having smart antenna
Provided are a method and apparatus for uplink carrier frequency synchronization and antenna weight vector estimation in an Orthogonal Frequency Division Multiple Access System (OFDMA) having a smart antenna. The inventive method comprises the steps of receiving and storing training symbols in the time domain transmitted to estimate an antenna ...

10/19/06 - 20060233269 - Method of determining the location of the fft window and the delay spread for the platinum broadcast channel estimator
In one embodiment, the invention comprises a channel estimation method, comprising determining a FFT window position, and calculating a delay spread. In another embodiment, the step of determining a FE window position comprises setting an initial position of the FFT window, computing an energy for each tap, time averaging said ...

10/19/06 - 20060233268 - Channel estimation using a minimized channel prediction interval
A receiver configured for: a) receiving (410) a first OFDM symbol and generating a plurality of demodulated symbols for the first OFDM symbol; b) generating (420) decoder output code symbols corresponding to a subset of the plurality of demodulated symbols; c) determining (430) that a set of the decoder output ...

10/12/06 - 20060227890 - Communication apparatus and communication method thereof
The present invention is provided to improve transmission efficiency by preventing interference between different networks during data transmission using a multicarrier communication method. A transmitter includes a phase vector setting unit and a multicarrier modulator. The phase vector setting unit rotates a phase of transmission data corresponding to each subcarrier ...

10/12/06 - 20060227889 - Wireless communication apparatus and wireless communication method
Disclosed is a wireless communication apparatus which receives, by multiple antennas, signals created by spatially multiplexing multiple transmit streams subjected to power allocation. The wireless communication apparatus has a channel matrix estimator which estimates a channel matrix of spatially multiplexed channels, a spatial demultiplexer which obtains an antenna receive weight ...

10/12/06 - 20060227888 - Apparatus and method for ft pre-coding of data to reduce papr in a multi-carrier wireless network
A subscriber station for use in a wireless network capable of communicating according to a multi-carrier protocol, such as OFDM or OFDMA. The subscriber station comprises a size M Fourier Transform (FFT or DFT) block for receiving input symbols and generating M FT pre-coded outputs and a size N inverse ...

10/12/06 - 20060227887 - Adaptive time-filtering for channel estimation in ofdm system
Time filtering channel estimates in a wireless communication system, such as an Orthogonal Frequency Division Multiplex (OFDM) system, can be used to improve the quality of channel estimates. The characteristics of an optimal channel estimate time filter can depend on the manner in which the channel estimate is determined as ...

10/12/06 - 20060227886 - Advanced receiver with sliding window block linear equalizer
A receiver or an integrated circuit (IC) incorporated therein includes a fast Fourier transform (FFT)-based (or hybrid FFT-based) sliding window block level equalizer (BLE) for generating equalized samples. The BLE includes a noise power estimator, first and second channel estimators, an FFT-based chip level equalizer (CLEQ) and a channel monitor ...

10/05/06 - 20060222099 - Channel length estimation and accurate fft window placement for high-mobility ofdm receivers in single frequency networks
A method of estimating a channel length (304) in a wireless receiver is disclosed. The receiver receives a signal (122) from a remote transmitter. The receiver selects a plurality (K) of different candidate channel lengths and determines a respective criterion value (402) of the signal for each of the plurality ...

10/05/06 - 20060222098 - Impulse noise gating in dsl systems
Embodiments of methods and apparatuses for gating impulse noise in a communication system are described. In one embodiment, a quality measure of a received signal on a communication channel is not adjusted when corruption by impulse noise in the received signal is detected. In another embodiment, tuning parameters of a ...

10/05/06 - 20060222097 - System and method for improving the performance of ofdm systems
A method for improving the performance of OFDM (Orthogonal Frequency Division Multiplexing) systems addresses the channel estimation, equalization and decoding problems of conventional techniques and provides improved performance in a wide range of operating conditions that include varying Signal to Noise Ratio (SNR) levels, data rates, and fading channels. The ...

10/05/06 - 20060222096 - Platform noise mitigation in ofdm receivers
Techniques and structures are presented for use in mitigating the effects of platform noise within a wireless device. ...

10/05/06 - 20060222095 - Method of robust timing detection and carrier frequency offset estimation for ofdm systems
A symbol detector for an OFDM receiver determines the correlation of corresponding samples of at least two received preamble symbol samples, one of the samples delayed a predetermined duration with respect to the other; determines a timing metric based on the correlation results; detects multiple peaks in the timing metric; ...

10/05/06 - 20060222094 - Channel estimation using linearly constrained filter coefficients
A system that includes a receiver (100) that is configured for: selecting (210) a set of demodulator output samples and a corresponding set of reference symbols each having a magnitude; generating (220) a set of raw channel estimates based on the set of demodulator output samples and the corresponding set ...

10/05/06 - 20060222093 - Method and apparatus for reference symbol aided channel estimation
A system that includes a receiver (100) that is configured for: selecting (210) a set of demodulator output samples and a corresponding set of reference symbols; generating (220) a set of raw channel estimates based on the set of demodulator output samples and the corresponding set of reference symbols; subdividing ...

10/05/06 - 20060222092 - Platform noise mitigation in ofdm receivers
Techniques and structures are presented for use in mitigating the effects of platform noise within a wireless device. ...

10/05/06 - 20060222091 - Subcarrier adaptive thresholding
A communication device may obtain a channel estimate, and may adjust power thresholds governing an adaptive bit loading scheme. The communication device may include a transceiver arranged to receive data from a remote transmitter on a plurality of subcarriers. The communication device may also include a controller coupled to the ...

09/28/06 - 20060215780 - Apparatus and method for transmitting a signal in a communication system
In a communication system using an Orthogonal Frequency Division Multiple Access (OFDMA) scheme, at least one value mapped to the number of threshold subchannels is compared with the number of subchannels allocated to a signal transmission apparatus in an associated Orthogonal Frequency Division Multiplexing (OFDM) symbol when transmission data including ...

09/28/06 - 20060215779 - Receiving method and receiving apparatus
A matched filter calculates correlation values between burst signals received and known data. A moving average unit calculates a moving average for the calculated correlation values in a period based on a guard interval. A detector detects the symbol start timing from the calculated moving average. An FFT unit performs ...

09/28/06 - 20060215778 - Automatic frequency control for a wireless communication system with multiple subcarriers
Techniques for performing frequency control in an OFDM system are described. In one aspect, frequency acquisition is performed based on a received pilot, and frequency tracking is performed based on received OFDM symbols. For frequency acquisition, an initial frequency error estimate may be derived based on the received pilot, and ...

09/28/06 - 20060215777 - Partial fft processing and demodulation for a system with multiple subcarriers
Techniques for efficiently performing partial FFT for subcarriers of interest are described. The N total subcarriers may be arranged into M sets. Each set may contain K subcarriers uniformly distributed across the N total subcarriers, where M·K=N. For the partial FFT, pre-processing is initially performed on time-domain samples to obtain ...

09/28/06 - 20060215776 - Apparatus and method for tracking sampling clock in multi-carrier communication system
An apparatus and method for tracking a sampling clock are disclosed. The apparatus includes a compensating unit compensating phases of a first and a second received symbols according to a compensating signal and thereby generating a first and a second compensated symbols; a data removal module removing a first predetermined ...

09/28/06 - 20060215775 - Digital cancellation of radio frequency interference
A method and system of canceling radio frequency interference (RFI) sourced from a narrow-band radio frequency transmitter to interfere with the operation of a multi-carrier modulation system. The spectral components of the RFI can be represented as a Taylor series of 1/(m−1/2) where m is an integer and (m−1/2) is ...

09/28/06 - 20060215774 - Method and device for ofdm channel estimation
A method and device for OFDM transmission, the method includes: (i) defining a channel estimation sequence that is characterized by a low peak to average ratio at a significant guard to information power ratio; and (ii) transmitting the channel estimation sequence over multiple over multiple sub-carriers. A method and device ...

09/28/06 - 20060215773 - Method for eliminating reception interference signal of space-time block coded orthogonal frequency division-multiplexing system in high-speed mobile channel
Disclosed herein is a method for eliminating the reception interference signal of a Space-Time Block Coded Orthogonal Frequency-Division Multiplexing (STBC-OFDM) system in a high-speed mobile channel. The method includes the following steps. At the first step, the gain of a channel combined at a receiving end is estimated in the ...

09/21/06 - 20060209976 - Telecommunications transmission systems
In a multi-carrier system employing OFDM, for example DMT, an adaptive channel equalizer is normally used, operating in the frequency domain. The sampling clock is controlled so that the time delay between the transmitter and the receiver is effectively eliminated. If the information used to control the sampling clock is ...

09/21/06 - 20060209975 - Multiple antenna communication system
A multiple antenna communication system is provided. In the multiple antenna communication system, a receiver selects a transmit eigenvector corresponding to a singular value resulting from the Singular Value Decomposition (SVD) of a channel matrix between Tx antennas and Rx antennas and feeds back the transmit eigenvector to a transmitter ...

09/21/06 - 20060209974 - Propagation path estimating method and apparatus
A propagation path estimation method for a receiver of a radio communication system in which band limiting of a signal is performed in signal transmission and reception. The method comprises: estimating an impulse response group of a propagation path of the signal; having the impulse response group pass through a ...

09/21/06 - 20060209973 - Pilot signal transmission for an orthogonal frequency division wireless communication system
Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/or biasing from different mobile stations over the same frequencies and ...

09/21/06 - 20060209972 - Techniques to detect radar in a communication signal
Techniques to detect radar signals in a communication signal for a wireless system are described. ...

09/21/06 - 20060209971 - Interference-weighted communication signal processing systems and methods
A level of interference affecting signal components of received communication signals is estimated and used to weight the signal components. The signal components in a each of a number of groups of signal components are weighted based on respective interference estimates to thereby adjust signal components for coloured interference, which ...

09/14/06 - 20060203927 - Systems and methods for implementing receiver transparent q-mode
In a receiver transparent Q-mode, i.e., a Q-mode that is only implemented by a transmitter, the receiver is unaware of the Q-mode state of the transmitter. In this type of Q-mode configuration, the transmitter could enter and exit Q-mode as desired while the receiver, could, for example, continue to function ...

09/14/06 - 20060203926 - Apparatus and method for detecting preambles according to ieee 802.11a wireless lan standard
A novel method and apparatus for short preamble detection within the framework of the 802.11a standard is described. The present invention can be easily implemented in both the radio part (preferred embodiment) and the baseband part (general case) of the receiver to provide short preamble detection. The inventive method and ...

09/14/06 - 20060203925 - Synchronization method for symbol boundary detection in uwb-ofdm
A method is presented for packet detection and symbol boundary location using a two-step sign correlation procedure. When the correlation crosses a threshold, a packet detection signal is generated to initiate processing of downstream blocks, and a symbol boundary location signal is generated for use in aligning data during processing. ...

09/14/06 - 20060203924 - Multi-carrier incremental redundancy for packet-based wireless communications
Methods and apparatus are disclosed herein for providing incremental redundancy in a wireless communication system to aid in error recovery. One or more redundancy versions are sent on different carriers than the primary version of information to be transmitted. At the receiver end the redundancy versions may be combined using ...

09/14/06 - 20060203923 - Method and communications system device for the code-modulated transmission of information
A method for the code-modulated transmission of information in a communications system via a carrier having at least two independent orthogonal resources, uses in particular a frequency band with a plurality of sub-resources as the first resource and the time as the second resource with a sequence of time slots ...

09/07/06 - 20060198455 - Transmitter and transmission control method used in random access communication environment
A transmitter comprises a frequency utilization status detector configured to detect the utilization status of an allocated frequency band based on a received signal, a symbol placement determination unit configured to determine placement of pilot symbols based on the detected status of frequency utilization, and a symbol placement unit configured ...

09/07/06 - 20060198454 - Adaptive channel estimation thresholds in a layered modulation system
Dynamic channel estimation thresholds allow for determining optimal threshold values for channel estimation in a layered-modulation wireless communication system. A channel estimation threshold can be used to remove or otherwise filter out channel estimate components that may be significantly influenced by noise. The channel estimation threshold value can be used ...

09/07/06 - 20060198453 - Impluse supression apparatus applied in ofdm system and related method thereof
An impulse suppression apparatus and method applied in an OFDM system for suppressing the impulse noise of a first time-domain signal are disclosed. The impulse suppression apparatus includes a noise blanker for generating a second time-domain signal through blanking the noise of the first time-domain signal, wherein each absolute value ...

09/07/06 - 20060198452 - Method to minimize degradation in a d-mpsk hierarchical modulation system
The present invention provides a method to minimize degradation in a D-MPSK hierarchical modulation system by adding additional data throughput (i.e., secondary information) as an offset to the primary signal transmitted by a SDARS terrestrial repeater. The present invention provides techniques for adding the additional throughput as Level 2 data ...

09/07/06 - 20060198451 - Distance division multiplexing
A general method for extracting an electromagnetic or other wave-propagated signal of a desired source from the overall received waveform containing the sum of signals from a multitude of such sources, independently of signal contents and modulation. The method comprises the steps of first expanding the spectrum of the received ...

09/07/06 - 20060198450 - Radio transmitter apparatus and modulation scheme selecting method
A wireless transmission apparatus that can accurately select an optimal modulation scheme on a per block basis in a multi-carrier communication system in which block division of subcarriers and adaptive modulation are performed. In this wireless transmission apparatus, a propagation path characteristics acquisition section (107) acquires the average SNR and ...

09/07/06 - 20060198449 - Receiver for a multi-carrier communication system
A receiver for a multi-carrier communication system receives training pilot carriers (TRPC) during a training symbol (T1, T2) which precedes data symbols (DS) which have data carriers (DC) and data pilot carriers (PC). The receiver has a correction unit (171) which supplies, under control of a control signal (CEC), a ...

08/31/06 - 20060193394 - Receiving method and receiving apparatus
Burst signals are received. An AGC unit determines gain for the received burst signal. A VGA unit amplifies the received burst signal by the determined gain. In the burst signal, Legacy STS is assigned in a header portion and MIMO-STS is assigned posterior to the Legacy STS. The AGC unit ...

08/31/06 - 20060193393 - Ofdm transmitter
An OFDM transmitter is configured to perform a peak reduction process on a signal sequence to be transmitted in a stepwise manner to transmit a peak processed transmission signal. The OFDM transmitter includes a dividing inverse fast Fourier transform unit (104) configured to divide the signal sequence to be transmitted ...

08/31/06 - 20060193392 - Apparatus for and method of compensation for frequency offset and channel variation in mimo-ofdm receiver
An apparatus for compensating for a frequency offset and a channel variation, includes: a frequency offset compensation unit estimating the frequency offset of receptions signals received via reception ends based on a final metric value of the reception signals, and a compensator compensating for the frequency offset of the receptions ...

08/31/06 - 20060193391 - Ordered retransmissions for arq in multicarrier systems
A first data symbol that includes a kth data bit is received over a multicarrier system. A first channel quality parameter is estimated for the first data symbol. A second data symbol that includes a retransmitted kth data bit is received. A second channel quality parameter for the second data ...

08/31/06 - 20060193390 - Methods and apparatuses for canceling correlated noise in a multi-carrier communication system
Embodiments of an apparatus, system, and method are described for a multi-carrier communication system that cancels at least some correlated noise estimated to be present in a channel in the multi-carrier communication system. Values of noise present on at least on reference channel in a multi-channel communication system may be ...

08/24/06 - 20060188035 - Method for seamlessly changing power modes in an adsl system
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

08/24/06 - 20060188034 - System and method for multiple signal carrier time domain channel estimation
The present invention provides a method of characterizing a frequency response of a transmission channel between a transceiver and a subscriber unit. The method includes once per predetermined interval of time, the transceiver transmitting a signal including multiple carriers, a plurality of the carriers including training symbols, a plurality of ...

08/24/06 - 20060188033 - Wireless receiver with anti-jamming
An embodiment of the present invention provides a receiver capable of receiving a signal carrying data in the presence of jamming interference, the receiver comprising an anti-jamming (AJ) processor, adapted to process the received signal so as to determine a frequency, phase and amplitude of the jamming interference, a jamming ...

08/24/06 - 20060188032 - Dual carrier modulator for modulating ofdm multi-carrier, ofdm transmitter therewith, and a method thereof
A dual carrier modulator that modulates an orthogonal frequency division multiplexing (OFDM) carrier, includes an input part receiving a predetermined number of coded bits; a memory part storing the coded bits received through the input part; a detection part detecting four bits among the coded bits in a predetermined order; ...

08/24/06 - 20060188031 - Intelligent demodulation systems and methods in an ofdma multicell network
An OFDMA communication system includes a plurality of terminals, with at least one of the terminals including at least one type of multi-user decoder adapted to decode a signal intended for the at least one terminal received on a subchannel of the system and adapted to decode at least a ...

08/17/06 - 20060182190 - Distribution line carrier transmitting device
There is provided a distribution line carrier transmitting device which supports, for example, frequency division communication and in which even a frequency band used for communication is variable, a filter to be used is changed according to the frequency band, so that an influence of noise is eliminated, and stable ...

08/17/06 - 20060182189 - Apparatus and method for optimally compensating for imbalance between in-phase and quadrature-phase in a zero-if ofdm receiver
An optimum I/Q imbalance compensating apparatus and method in a zero-IF OFDM receiver. In the apparatus, a first compensator generates a first symbol by removing interference from a second distorted symbol on an (Ns−m+1)th subcarrier from a first distorted symbol on an mth subcarrier by a first compensation coefficient in ...

08/10/06 - 20060176969 - Apparatus and method for reducing the crest factor of single carrier or multi-carrier signals
An apparatus for reducing the crest factor of a multi-carrier transmission system. The apparatus comprises a plurality of single carrier crest factor reduction circuits. Each of the single carrier crest factor reduction circuits receives a selected one of a plurality of single carrier signals and generates a crest factor reduced ...

08/10/06 - 20060176968 - Adaptive viterbi decoder for a wireless data network receiver
A configurable Viterbi decoder to decode a coded signal for inclusion in a radio receiver for implementing the physical layer receiving function (PHY) of a wireless data network. The decoder includes a branch metric generator with an input to the coded signal, an ACS subsystem coupled to the branch metric ...

08/10/06 - 20060176967 - Time correlation of signal power to distortion characteristics
Time correlation of signal to distortion characteristics is achieved by acquiring time domain data for a frequency band representing a communication signal, the communication signal having multiple channels. The time domain data is simultaneously converted to frequency and demodulation domain data in sequential time blocks. The frequency and demodulation domain ...

08/10/06 - 20060176966 - Variable cyclic prefix in mixed-mode wireless communication systems
A method in a wireless communication network infrastructure entity (200), including transmitting a plurality of symbols in a sequence, some of the symbols associated with a first transmission mode, for example, point-to-point, and some other symbols associated with a second transmission mode, for example, point-to-multipoint, different than the first transmission ...

08/10/06 - 20060176965 - System and method for removing interfering narrowband signals from wide bandwidth receive signal
In accordance with the present invention, the system and method removes interfering signals from a communications signal and includes a Fast Fourier Transform (FFT) circuit for taking the FFT of a received signal and segmenting the signal into segments. A frequency shifting circuit can shift each segment in frequency to ...

08/03/06 - 20060171480 - Multi-frequency data transmission channel power allocation
A method of controlling a communication device that is operable to transmit digital data over a plurality of frequency channels. The method includes selecting an initial transmission power and a corresponding data rate for each channel. The method also includes identifying in a first channel a first ratio of a ...

08/03/06 - 20060171479 - Apparatus and method using multiple modulation schemes in an ofdm/ofdma wireless network
A flexible and scalable deployment of orthogonal frequency division multiplexing (OFDM) technology in a mobile cellular system, including a system that deploys multiple channels within a common base station, in which different modulation techniques are used to compensate for adjacent-channel interference. ...

07/27/06 - 20060165189 - Adaptive modulation scheme and coding rate control method
A radio communication system for enabling control of a modulation scheme following variation in the propagation channel and control of a coding rate in a small amount of delay and arithmetic operation. In order to attain the object explained above, a transmitter station and a receiver station use in common ...

07/27/06 - 20060165188 - Method for sending channel quality information in a multi-carrier radio communication system, corresponding mobile terminal and base station
The present invention relates to a method for sending channel quality information in a multi-carrier radio communication system comprising at least one mobile terminal and at least one base station, said channel quality information being sent on a signaling channel by said mobile terminal to said base station. According to ...

07/27/06 - 20060165187 - Multiplex signal error correction method and device
A method of reducing a phase error caused by a plurality of error sources in a signal which is present in a digital frequency representation in the form of a sequence of a plurality of digital partial signals which are associated with a number of subcarriers (k) of a carrier. ...

07/20/06 - 20060159190 - System and method for expanding multi-speaker playback
A method includes splitting and filtering a left input signal and a right input signal to produce a plurality of frequency sub-bands. Each of the frequency sub-bands includes a left sub-band signal and a right sub-band signal. The method also includes processing the left and right sub-band signals associated with ...

07/20/06 - 20060159189 - Methods and systems for performing an overlap-and-add operation
A system is provided that includes a first device 110A that transmits an information symbol with a zero-padded suffix (ZPS) and a second device 110B that receives the information symbol with the zero-padded suffix. The second device 110B performs a Fourier transform on at least one sample of the information ...

07/20/06 - 20060159188 - Wireless communication apparatus and wireless communication method
Disclosed is a wireless communication apparatus which synthesize signals received from a plurality of antennas to separate the signals into synthesis signals of a plurality of logical channels. The apparatus has a first phase corrector correcting a phase of a reception signal by estimating an amount of phase correction by ...

07/20/06 - 20060159187 - System and method for utilizing different known guard intervals in single/multiple carrier communication systems
A system and method for a transceiver structure, where Different Known Guard Intervals (DKGI) are appended to multiple, consecutive data blocks and are then used in combination with Channel State Information (CSI) to restore cyclic convolution in the time domain. Once restored, the CSI and cyclic convolution are transformed into ...

07/13/06 - 20060153310 - Time-domain equalizer for discrete multi-tone based dsl systems with cyclic extension in training
The present invention provides for a method and system to implement time-domain equalizer (TEQ) training to shorten the channel impulse response of twisted copper lines for DMT-based VDSL systems. The coefficients of TEQ are trained when training signal has cyclic extension (CE), such as specified in current VDSL standard and ...

07/13/06 - 20060153309 - Gradient based method and apparatus for ofdm sub-carrier power optimization
In one aspect thereof this invention provides a method to increase data throughput in an Orthogonal Frequency Division Multiplex (OFDM) wireless communications system. The method includes modeling data throughput as a function of received Signal to Noise Ratio (SNR) with a sigmoid function to produce a throughput curve characterized as ...

07/06/06 - 20060146949 - Multicarrier communication system and methods for communicating with subscriber stations of different bandwidth profiles
A multicarrier base station communicates with subscriber stations of different bandwidth profiles by allocating time slots in downlink and uplink frames and subcarriers of a single multicarrier communication channel to various bandwidth subchannels. ...

07/06/06 - 20060146948 - Adaptive pilot allocation method and apparatus for use in a communication system
A method and apparatus are provided for adaptively allocating pilots in a pilot-aided channel estimation system. A multipath delay is measured between a base station (BS) and a mobile station (MS). A distribution density of pilots of a signal to be transmitted between the BS and the MS is controlled. ...

07/06/06 - 20060146947 - Method and circuit for detecting guard intervals in ofdm communication systems
A circuit for detecting a guard interval in an orthogonal frequency division multiplication (OFDM) communication system, using two successive autocorrelation calculations for a received sample train. The circuit determines a guard interval by calculating the maximum correlation value first autocorrelation calculation step (delaying an OFDM signal by the length of ...

07/06/06 - 20060146946 - Method of determining a metric for evaluating the transmission quality of a data frame transmitting by a communication system
The present invention concerns a method of determining a metric for evaluating an error probability of a data frame transmitted by a first device to a second device through communication channels, a data frame comprising a plurality of symbols, wherein the metric is determined at least from at least one ...

07/06/06 - 20060146945 - Method and system for channel equalization and crosstalk estimation in a multicarrier data transmission system
Improved techniques for concurrent channel equalization and far-end crosstalk channel compensation (e.g., estimation and/or cancellation) in a multicarrier data transmission system are disclosed. The improved techniques can produce coefficients for an electronic filter that provide channel equalization and for an electronic filter that provides cancellation of the far-end crosstalk. These ...

07/06/06 - 20060146944 - System and method of processing frequency-diversity signals with reduced-sampling-rate receiver
A system and method of frequency-diversity OFDM with a sampling rate less than the Nyquist rate for ultra-wideband devices are described. The channel encoder is used to encode at least one input data stream to a plurality of codewords. The evaluation device coupled to the channel encoder and having a ...

07/06/06 - 20060146943 - Apparatus and related methods to aid in system identification in a heterogeneous communication system environment
An apparatus and associated methods to aid in system identification in a heterogeneous communication environment is generally described herein. ...

06/29/06 - 20060140298 - Reduced complexity multicarrier precoder
A reduced complexity precoder provides an efficient method and structure to precode a vector-signal-point sequence for transmission through a band-limited channel. The precoder enables a block-oriented receiver to recover an underlying data stream in the presence of inter-symbol interference and noise. The precoder structure is applicable to multicarrier systems such ...

06/29/06 - 20060140297 - Multicarrier receiver and methods of generating spatial correlation estimates for signals received with a plurality of antennas
In a multicarrier receiver, spatial correlation estimates are enhanced by multiplying by weighting values generated from a channel length estimate. The channel length estimate is calculated from a channel estimate (e.g., an estimate of the channel response function) and a signal-to-noise ratio estimate. The spatial correlation estimates represent the correlation ...

06/29/06 - 20060140296 - Apparatus and method for reducing the peak-to-average power ratio of ofdm/ofdma signals
An apparatus is provided for reducing the peak-to-average power ratio (PAPR) of a multicarrier transmission system. The apparatus comprises a detector for receiving a plurality of symbols to be transmitted and determining a peak amplitude of the plurality of symbols and a controller for determining if the peak amplitude associated ...

06/29/06 - 20060140295 - Multi sub-carrier communication system and method providing improved frequency equalization performance
There is provided a multi sub-carrier communication system for providing improved performance of a frequency equalizer and a method thereof. The multi sub-carrier communication system includes a frequency equalization coefficient (vector) calculation unit that receives an equalized signal outputted from a frequency equalizer and periodically calculates a new frequency equalizer ...

06/29/06 - 20060140294 - Block modulation
A device for block transmission involving a first number of subcarriers (N), comprising: storage means for storing at least one transmission matrix having a dimension equal to the first number. The transmission matrix being arranged so that the columns of the transmission matrix represent a first transmission characteristic and the ...

06/29/06 - 20060140293 - Method for detecting signal and estimating symbol timing
A method for detecting signal and estimating symbol timing is provided. The method is applicable to the receiver in an OFDM system. The method uses the autocorrelation of the short preamble of input signals to detect signals, and performs the coarse frequency offset compensation at the same time. Then, the ...

06/29/06 - 20060140292 - Process of synchronization in the time and frequency domain of multiple equipments in a transmission system with ofdm modulation
Allows synchronisation of multiple users by means of improving the estimation of the start of the OFDM symbols and improving the estimate of frequency error in noisy environments or in frequency selective channels. It is characterized by the decomposition of the received signals x(n9, that contain data and synchronization sequences, ...

06/29/06 - 20060140291 - Architecture for multi-channel digital signal processing
The present invention is directed to a multi-channel signal processing system that includes a fast Fourier transform (FFT) module configured to perform an FFT using a first channel time domain sample as the in-phase component of a complex signal input, and by using the second channel time domain sample as ...

06/29/06 - 20060140290 - Training symbol format for adaptively power loaded mimo
Training symbol formats are provided for use in a MIMO based wireless communication system that uses adaptive power loading. In at least one embodiment, a training symbol format is used that is capable of enhancing training symbol signal to noise ratio (SNR). ...

06/29/06 - 20060140289 - Method and apparatus for providing an efficient pilot scheme for channel estimation
An approach for utilizing a pilot scheme in a spread spectrum communication system (e.g., Multi Carrier Code Division Multiple Access (MC-CDMA)) is provided. A communications link includes a sub-bands and a single pilot channel that is designated for the sub-bands for channel estimation. Pilot symbols transmitted over the single pilot ...

06/29/06 - 20060140288 - System and method for transmission and reception of multicarrier data signals
Apparatus and method for transmitting information, utilizing a multicarrier waveform containing the information. The waveform presents symmetrically-shaped first and second sequential portions which are substantially equal in length. All subcarriers are restricted in phase values to 0 and π, or alternatively, π/2 and 3π/2. One, but not both, of the ...

06/29/06 - 20060140287 - Simultaneous bi-directional link
A memory system with a simultaneous bi-directional link includes a controller, a memory device and a set of signal lines coupled to the controller and the memory device. Simultaneous communication between the controller and the memory device on the set of signal lines uses a first band of frequencies, and ...

06/22/06 - 20060133529 - Apparatus and method for performing time domain channel estimation in a communication system
In an orthogonal frequency division multiplexing (OFDM) system, channel estimates of pilot subcarriers in a current input symbol are input, and time domain channel estimation for data subcarriers positioned between adjacent pilot subcarriers is performed by linear interpolating channel estimates of the adjacent pilot subcarriers associated with each of the ...

06/22/06 - 20060133528 - Receiver and communication method for digital multi-carrier communication
A receiving apparatus and receiving method employ a digital multi-carrier transmission technique utilizing a real coefficient wavelet filter bank in digital demodulation. The receiving apparatus may include a memory configured to store received waveform data corresponding to 2K symbols or more and a wavelet transformer configured to perform a wavelet ...

06/22/06 - 20060133527 - Residual frequency, phase, timing offset and signal amplitude variation tracking apparatus and methods for ofdm systems
An error tracking apparatus and method for tracking a residual frequency error, a phase error, a timing error, and a signal amplitude variation to enhance a phase error tracking performance and a tracking speed in an orthogonal frequency division multiplexing (OFDM) system is provided. The error tracking apparatus and method ...

06/22/06 - 20060133526 - Method for joint time synchronization and frequency offset estimation in ofdm system and apparatus of the same
Embodiments of the present invention include a method for performing joint time synchronization and carrier frequency offset estimation in a wireless communication system, comprising steps of: on a transmitter: performing frequency domain spreading and interleaving on input data by using a predetermined spreading factor (SF) to generate a frequency domain ...

06/22/06 - 20060133525 - Symbol timing estimation in communication systems
A symbol timing estimation method is provided for use in a communication system, for example an orthogonal frequency division multiplexing system having a cyclic prefix extension CPE. Each symbol in a transmitted signal comprises N symbol samples, and the CPE has L symbol samples. The method comprises receiving the signal ...

06/22/06 - 20060133524 - Multicarrier signal transmission apparatus, multicarrier signal receiving apparatus, multicarrier signal transmission method, multicarrier signal receiving method, and communication system
A multicarrier signal transmission apparatus able to adjust the balance between the quality of reception and generation of an out-band spurious wave by a simple configuration, comprising a peak detector for detecting a peak part of a transmitted multicarrier signal, a window function generator for generating a window function of ...

06/22/06 - 20060133523 - Multi-tone system with oversampled precoders
A multi-tone system includes a data transmission circuit with an interface for receiving a data stream for transmission, a data steam splitter that splits the data stream to produce multiple substreams and a plurality of parallel data preparation circuits. Each data preparation circuit prepares a respective substream for transmission and ...

06/22/06 - 20060133522 - Mc-cdma multiplexing in an orthogonal uplink
Techniques are provided to support multi-carrier code division multiple access (MC-CDMA) in an orthogonal uplink of a wireless communication system. A method of wireless multi-carrier communications comprises dividing sub-carriers on an uplink into non-overlapping groups, allocating a time-frequency block including a hopping duration and a non-overlapped group, respectively, assigning a ...

06/22/06 - 20060133521 - Performance based rank prediction for mimo design
The performance of a Single Code Word (SCW) design with low complexity MMSE receiver & rank prediction is similar to the Multiple Code Word (MCW) design with successive interference cancellation (SIC). A method of rank prediction comprises calculating MIMO channel matrices corresponding to layer transmissions for each tone, calculating signal-to-noise ...

06/22/06 - 20060133520 - Method of modulation and demodulation of a digital signal, in particular in a frequency band affected by flat fading, associated modulator and demodulator
A method of modulating a digital signal of width L in frequency on a given useful frequency band is described The digital signal is separated into N blocks bn (1≦n≦N). The given useful frequency band is split into N contiguous parts Pn. Channels Cn, of width ln in frequency, lying ...

06/22/06 - 20060133519 - Method and system for providing window shaping for multiline transmission in a communications system
A method and system for providing window shaping for multiline transmission in a communications system are described. A last portion of a prefix symbol is extracted. A prefix with a prefix window is shaped to create a shaped prefix. A DMT symbol is shaped with a DMT window to create ...

06/15/06 - 20060126750 - Method and apparatus for combining transponders on multiple satellites into virtual channels
A satellite communications system provides an information channel between remotely located transmitters and receivers. A virtual satellite system provides the same service, but divides the signal either in power or in data content into subchannels such that any particular signal is conducted to the intended receiver via a plurality of ...

06/15/06 - 20060126749 - Communications systems
In a multi user communication system, subcarriers are allocated to subchannels using a quality measurement for each subchannel. An initial sub carrier is allocated to each subchannel, and a quality metric measured. Subsequent subcarriers are allocated in dependence upon the quality measurement for each subchannel. The subchannel with the lowest ...

06/15/06 - 20060126748 - Method for reducing peak-to-average power ratio of multi-carrier modulation
A method for reducing the peak-to-average power ratio of the time-domain signal in a communication system using multi-carrier modulation is provided herein. The present invention is based on the method of recursive clipping and filtering to reduce the peak-to-average power ratio and out-of-band spectrum, but during the recursive process, the ...

06/15/06 - 20060126747 - Block linear equalization in a multicarrier communication system
A method and apparatus for channel equalization in a multi-carrier communication system. The method may include receiving a symbol having multiple sub-carriers and reducing an error on at least one of the sub-carriers of the symbol by adding to it, one or more weighted multiples of other sub-carriers. The added ...

06/08/06 - 20060120473 - Method and system for interference averaging in a wireless communication system
A family of methods for interference averaging in multicarrier systems, such as orthogonal frequency division multiplexing (OFDM) systems. The methods can provide interference averaging in situations where an interfering co-channel is either partially or fully loaded. For partially loaded systems, subcarrier puncturing, frequency domain repetition, time domain repetition, and hybrid ...

06/08/06 - 20060120472 - System and method for multi-carrier modulation
A method of compensating for carrier frequency and phase errors of a received multi-carrier modulated signal. The received multi-carrier signal including modulated carriers for transmitting known data and unmodulated carriers for error correction, comprising, time domain down converting the received multi-carrier signal to base-band to provide a down-converted signal, the ...

06/08/06 - 20060120471 - Tree structured multicarrier multiple access systems
A Tree-structured multicarrier multiple access communication system in a multiple access environment having a number of interfering signals. In one embodiment an environment estimator estimates and tracks the number of interfering signals of the environment. A code selector determines an optimal spreading code represented by the environment, and identifies an ...

06/08/06 - 20060120470 - System for communicating channel quality information
In transmitting channel quality information (CQI) by a mobile station (MS) in a communication system, the mobile station receives from a base station (BS) information of an allocation of a CQI channel and information as to a modulation to be performed on the CQI. CQI channel signal is generated based ...

06/08/06 - 20060120469 - Multiple antenna multicarrier transmitter and method for adaptive beamforming with transmit-power normalization
In a multi-antenna, multicarrier transmitter, a multicarrier communication signal is generated by normalizing beamforming matrices based on an average subcarrier power loading for each of the transmit antennas. One or more spatial streams may be transmitted by two or more antennas. ...

06/08/06 - 20060120468 - Method and system for guard interval size detection
Methods and systems for detecting a guard interval size in a received OFDM signal are provided. A correlation calculator calculates a preliminary correlation signal based on a digitized signal, and generates a correlation signal corresponding to each possible guard interval size by summing the preliminary correlation signal in accordance with ...

06/08/06 - 20060120467 - Packet communication device
A multicarrier communication method and a multicarrier communication apparatus used for the method for adjusting the arrangement in code block units according to the actual reception state of the multicarrier signal, when arranging code blocks generated through error correcting coding processing not only in the time axis direction but also ...

06/01/06 - 20060115012 - Increased discrete point processing in an ofdm communication system
Methods and apparatus provide increased symbol length with more subcarriers in a fixed-bandwidth system. The subcarriers spacing may be reduced to provide increased symbol length and enable higher throughput. In one implementation, a system compatible with the IEEE P802.11n proposal can use 128 subcarriers in 20 MHz operation to provide ...

06/01/06 - 20060115011 - Orthogonal frequency division multiplexing (ofdm) receiver
An OFDM receiver apparatus mounted on a movable object for receiving an OFDM signal, includes a plurality of directional antennas which receive an OFDM signal, an estimator to estimate a center frequency of a spectrum of a Doppler component from one of the received signals or a multiplexed signal obtained ...

06/01/06 - 20060115010 - Apparatus and method for reducing a peak to average power ratio in a multi-carrier communication system
An apparatus and method for reducing a Peak to Average Power Ratio (PAPR) in a broadband wireless communication system. A transmitter classifies symbols into full-symbols and sub-symbols, and divides a transmission full-symbol into at least two sub-symbols and transmits the sub-symbols, when the transmission full-symbol has a PAPR larger than ...

05/25/06 - 20060109926 - Method and apparatus for transmitting data in a time division duplexed (tdd) communication system
Techniques to process data for transmission in a time division duplexed (TDD) communication system. In one aspect, the frequency response of a forward link is estimated at a base station based on reverse link transmissions (e.g., pilots) from a terminal. Prior to a data transmission on the forward link, the ...

05/25/06 - 20060109925 - Method and apparatus for error reduction in an orthogonal modulation system
A method and apparatus reduces error in a communication system that includes multiple orthogonal subcarriers by suppressing a subcarrier in a transmitting communication device and by equalizing a received signal in a receiving communication device. Subcarrier suppression is based on a determination of a signal quality metric with respect to ...

05/25/06 - 20060109924 - Apparatus and method for signal transmission/reception according to pilot modulation in a multi-carrier communication system
Disclosed is a system and method for modulating a pilot symbol sequence in a multi-carrier communication system. The method including producing a pilot symbol sequence corresponding to a predetermined time interval by removing a data symbol sequence from time domain signal to be transmitted, the time domain signal including the ...

05/25/06 - 20060109923 - Subcarrier cluster-based power control in wireless communications
Devices, systems and techniques to monitor signal fading based on a cluster of subcarriers at a receiver and feedback monitored signal fading to a transmitter in wireless communication systems such as OFDM and OFDMA systems. ...

05/25/06 - 20060109922 - Iterative channel and interference estimation with dedicated pilot tones for ofdma
Estimation of channel characteristics and interference level in a time-varying multi-carrier multi-user systems is carried out concurrently. To perform the estimation, a multitude of data symbols and dedicated pilot symbols are transmitted over the channel. Next, an initial estimate value is selected for the interference level. The initial estimate value ...

05/25/06 - 20060109921 - Combining coefficient estimation apparatus capable of compensating for phase noise of ofdm system and combining coefficient estimation method thereof
An apparatus for receiving OFDM signals via at least two antennae is disclosed. The apparatus includes a converter for converting a plurality of OFDM symbols received via each antenna to a plurality of sub carrier signals, wherein each sub carrier signal corresponds to one of a plurality of sub carriers; ...

05/25/06 - 20060109920 - Ofdm wireless receiver
A heterodyne receiver converts a received high frequency signal into an intermediate frequency signal and demodulates a base band signal from a intermediate frequency signal. Low-pass filters cut the high frequency components of the baseband signal, and AD converters sample the output signal of those low-pass filters, convert them to ...

05/25/06 - 20060109919 - Wireless communications device providing time and frequency-domain channel estimates interpolation and related methods
A wireless communications device which may include a wireless receiver for receiving wireless signals comprising unknown data portions over a channel, and a demodulator connected to the wireless receiver. The demodulator may be for estimating a delay spread and a fade rate associated with the channel, determining a desired time-domain ...

05/18/06 - 20060104376 - Ofdm signal receiver and receiving method
A receiver having a frequency-deviation detector which includes: a storage for locating and storing the frequency-domain symbol-signal in a two-dimensional data area on a two-dimensional space corresponding to a carrier frequency and a symbol time; a calculator for calculating the transfer characteristic of a pilot signal; a Fourier transformer for ...

05/18/06 - 20060104375 - Method and system for improving the quality of a radio signal
The invention relates to a method and a system for improving the quality of a radio signal, particularly for systems according to the IEEE 802.16 standard. In the case of a wireless transmission of radio signals the signals often doesn't reach the receiver in a direct way, but are scattered ...

05/18/06 - 20060104374 - Mapping strategy for ofdm-based systems using h-arq
A wireless communication device adapted so that, in response to a repeat request indicating a communication signal, the device wirelessly retransmits the communication signal using a remapping of bits into at least partially different frequencies in the retransmission compared to the original transmission. ...

05/18/06 - 20060104373 - Ofdm peak-to-average power ratio reduction by combined symbol rotation and inversion with limited complexity
A signal scrambling method based on combined symbol rotation and inversion (CSRI) for the peak-to-average power ratio (PAPR) reduction of OFDM signals. By dividing OFDM sequences into subblocks and performing symbol rotation and inversion in each subblock, high degrees of freedom are available to offset the possibility of encounting poor ...

05/18/06 - 20060104372 - Coding system
The present invention relates to a coding strategy for joint modulation coding and ECC coding. It relates in particular to the situation where 2D coding is performed along one-dimensionally evolving strips containing a number of bit rows in the radial direction of the strip, which is orthogonal to the former ...

05/11/06 - 20060098752 - Apparatus and method for transmitting a preamble and searching a cell in an ofdma system
An apparatus and method for generating a preamble and searching a cell using the generated preamble in an orthogonal frequency division multiple access (OFDMA) system. Q cyclic shift values and P pseudo-random noise (PN) codes are used to distinguish N cells. One of the P PN codes is cyclically shifted ...

05/11/06 - 20060098751 - Methods of automatically detecting spectrum inversion and related terrestrial digital video broadcasting receivers
DVB-T receivers and methods may provide automatic detection of spectrum inversion using continual pilot correlation. A DVB-T receiver may include a demodulator, a fast Fourier transformation (FFT) unit, and a spectrum inversion detector. The demodulator may demodulate a received DVB-T digital signal according to a spectrum inversion signal, and the ...

05/11/06 - 20060098750 - Circuit and method for reducing impulse noise
A circuit and method for reducing impulse noise. The circuit may include a noise measuring unit which determines whether a first logic level or a delayed version of a received signal sample will be output based on a comparison of absolute values of a plurality of delayed versions of the ...

05/11/06 - 20060098749 - Apparatus and method for detecting ranging signal in an orthogonal frequency division multiple access mobile communication system
An apparatus and method for receiving a ranging signal in an OFDMA mobile communication system are provided. The ranging signal receiving apparatus including, a ranging subchannel extractor for extracting subcarrier values with a ranging signal from a (FFT) signal; a plurality of multipliers for code-demodulating the sub-carrier values by multiplying ...

05/11/06 - 20060098748 - Multi-carrier communication system and communication method thereof
A multi-carrier communication system is disclosed. The multi-carrier communication system includes a transmitting module for generating a first time-domain signal by performing an inversed Fourier transform upon a transmitting data; a receiving module for receiving a second time-domain signal and for generating a decoded data by performing a Fourier transform ...

05/11/06 - 20060098747 - Coded ofdm system and method with improved papr reduction
A system and method is herein disclosed for reducing peak-to-average power ratio in an orthogonal frequency division multiplexing system which utilizes label bits inserted at predetermined locations of an information stream prior to encoding. ...

05/04/06 - 20060093053 - Ofdm channel estimation in the presence of interference
Systems and methods for estimating channel response in the presence of interference. Interference and/or noise present on received training symbols is estimated. Based on the measured noise and/or interference, a weighting among training symbols is developed. Channel response is then estimated based on a weighted least squares procedure. ...

05/04/06 - 20060093052 - 2n-point and n-point fft/ifft dual mode processor
A 2N-point and N-point FFT/IFFT dual mode processor is provided. The processor includes a butterfly operator, the first and second MUXs, and the first and second N-point FFT processors. The butterfly operator receives 2N data and butterfly-operates on the received 2N data when receiving a control signal ‘0’ from the ...

05/04/06 - 20060093051 - Method and device for resisting dc interference of an ofdm system
A method and device for resisting DC interference of an orthogonal frequency division multiplexing (OFDM) system are used to obtain interference of a DC source to an OFDM system corresponding to various modulation types and frequency offsets for producing a weighting look-up table when the OFDM makes simulation. Different weights ...

05/04/06 - 20060093050 - Symbol synchronization for communication
A communication system and method is disclosed that performs symbol boundary synchronization by generating a symbol alignment estimate from a partial signal correlation; and then refining the symbol alignment estimate via a carrier phase calculation. To generate the symbol alignment estimate, two methods are disclosed. After an estimate is determined, ...

04/27/06 - 20060088116 - Frequency correlation based synchronization for coherent ofdm receiver and apparatus thereof
An apparatus for synchronizing pilots contained in symbols received by a receiver in a multicarrier transmission system and a method thereof are provided. Frequency or Time-frequency correlation-based scheme, with exploitation of time-frequency correlation characteristics of the pilots, may be used for identifying the positions of the pilots in frequency or ...

04/27/06 - 20060088115 - System and method for providing 3-dimensional joint interleaver and circulation transmissions
System performance in wireless communication is improved by increasing diversity in time, space and frequency. Information to be transmitted is processed by a convolution encoder to produce encoded bits. The encoded bits are interleaved and mapped to subcarriers. Symbols are created from the subcarriers and the symbols are transmitted so ...

04/27/06 - 20060088114 - Methods and apparatus for circulation transmissions for ofdm-based mimo systems
System performance in wireless communication is improved by increasing diversity in time, space and frequency. In OFDM-based MIMO systems in which the number of antennas M is greater then the number of simultaneously transmitted OFDM symbols N, circulation transmissions according to the present invention improve signal diversity. In symbol-based circulation ...

04/27/06 - 20060088113 - Method and circuit arrangement for reducing rfi interference
In a method for reducing RFI interference in a DMT data transmission a compensation signal for the purpose of reducing an RFI interference signal superposed on a transmitted DMT reception signal is generated. Only carrier frequencies of the DMT reception signal in the vicinity of the interference frequency of the ...

04/27/06 - 20060088112 - Process and a system for transmission of data
A process and a system for transmission of data in a multi-carrier Orthogonal Frequency Division Multiplexing (OFDM) communication system. ...

04/27/06 - 20060088111 - Tps decoder in an orthogonal frequency division multiplexing receiver
A receiver for orthogonal frequency division multiplexing (OFDM) signals, including an A/D converter for converting received analog signals to a digital signal data stream and an OFDM demodulator for producing a first set of complex I and Q components of subcarriers from the digital signal data stream. The receiver includes ...

04/20/06 - 20060083326 - System for wireless resource assignment in multiband ofdm
A multi-band orthogonal frequency division multiplexing (OFDM) system transmits the same symbol at least two times, and a receiving end can receive transmission data from a transmitting end accurately even when an error occurs from a wireless resource used by the multi-band OFDM system. To this end, the multi-band OFDM ...

04/20/06 - 20060083325 - Method and receiver circuit for reducing rfi interference
In a method for generating a compensation signal for the compensation of at least one RFI interference signal that, in a DMT transmission, is permanently superposed on a received DMT reception signal being divided into a multiplicity of channels at least one reference channel from the multiplicity of channels is ...

04/20/06 - 20060083324 - Method and apparatus for detecting transmission errors for digital subscriber lines
A multi-carrier communication system receives a plurality of data frames comprised of a plurality of bit groups in a data stream of the multi-carrier communication system, wherein up to R bit groups are identified as corrupted by analyzing corresponding tone values, and corrects the up to R bit groups associated ...

04/20/06 - 20060083323 - Method and apparatus for detecting transmission errors for digital subscriber lines
A multi-carrier communication system receives a plurality of data frames comprised of a plurality of bit groups in a data stream of a multi-carrier communication system, wherein one or more data frames are corrupt data frames, and corrects each corrupt data frame. ...

04/20/06 - 20060083322 - Method and apparatus for detecting transmission errors for digital subscriber lines
A multi-carrier communication system receives up to R corrupted bit groups in one or more data frames of a multi-carrier communication system and corrects the up to R corrupted bit groups in the one or more data frames. ...

04/20/06 - 20060083321 - Multi-carrier communication bit-loading in presence of radio-frequency interferers
An apparatus and method of compensating for radio frequency interference (RFI) if present in a tone in a multiple tone system to derive an equivalent noise power that can be used in bit-loading to achieve a better bit rate. ...

04/13/06 - 20060078060 - Multicarrier transmission system with low power sleep mode and rapid-on capability
A muticarrier transceiver is provided with a sleep mode in which it idles with reduced power consumption when it is not needed to transmit or receive data. The full transmission and reception capabilities of the transceiver are quickly restored when needed, without requiring the full (and time-consuming) initialization commonly needed ...

04/13/06 - 20060078059 - Apparatus and method for allocating subchannel and power in an orthogonal frequency division multiple access system
An apparatus and method for allocating transmission power of a subchannel for each individual user in an orthogonal frequency division multiple access (OFDMA) system. The apparatus and method comprises determining the number-of-transmission bits per symbol approximating an estimated signal-to-interference ratio (SIR) for each of subchannels when transmission power is uniformly ...

04/13/06 - 20060078058 - Orthogonal frequency division multiplexing (ofdm) receiver capable of correcting in-phase and quadrature-phase mismatch and method thereof
An OFDM receiver includes a demodulator unit being coupled to a received signal for demodulating both an in-phase (I) component and a quadrature-phase (Q) component of the received signal; a serial to parallel unit for converting the output of the demodulator to a plurality of parallel paths, each path corresponding ...

04/06/06 - 20060072678 - System and method for cellular communications
A a system for allocating subcarriers to subscribers, comprising a subcarriers allocation controller, connected to a subcarrier modulation unit in a transmitter and to a subcarrier demodulation unit in a receiver for setting a group of subcarriers to be used therein. The transmitter and the receiver are part of the ...

04/06/06 - 20060072677 - Method and apparatus for implementing space frequency block coding in an orthogonal frequency division multiplexing wireless communication system
The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading ...

03/30/06 - 20060067417 - Transmission method for ofdm-mimo communication system
A data transmission method in a MIMO-OFDM communication system including at least one receiver for receiving a signal through a plurality of reception antennas and a transmitter for selecting a transmission channel using channel information being fed back from the receiver and transmitting a signal through a plurality of transmission ...

03/30/06 - 20060067416 - Transmission format indication and feedback in multi-carrier wireless communication systems
A method is provided for specifying a transmission mode for each signal portion of a multi-carrier signal transmitted between a first device and a second device. The method includes defining an adaptive modulation and coding (AMC) set divided into a plurality of subsets wherein each of the plurality of subsets ...

03/30/06 - 20060067415 - Method and apparatus for increasing data throughput in a multiple antenna communication system using additional subcarriers
Methods and apparatus are provided for increasing data throughput in a multiple antenna communication system using additional subcarriers. The multiple antenna communication system includes at least one legacy system employing an N1 point fast Fourier transform (FFT) within a bandwidth, BW1. Data is transmitted using an N2 point inverse FFT ...

03/30/06 - 20060067414 - Envelope stabilization method and apparatus
A system and method is proposed to significantly reduce the peak to average power ratio (PAPR) for an OFDM system by stabilizing the signal envelope. By using partial response (PR) signaling to spread each sub-symbol over multiple subcarriers, the signal is first compress in time. The signal is then rearranged ...

03/30/06 - 20060067413 - Multicode transmission using walsh hadamard transform
A symbol sequence contained in a received signal comprising a cyclic convolution of a Walsh code multiplexed signal and a channel impulse response of a multipath channel is detected using Walsh Hadamard domain equalization techniques. The method comprises converting the received signal and the channel impulse response of the multipath ...

03/30/06 - 20060067412 - Multicarrier receivers and methods for detecting cyclic prefixes having unknown lengths
A multicarrier receiver sequentially correlates two training symbols to determine a length of a cyclic prefix associated with each of the training symbols. ...

03/30/06 - 20060067411 - Method and apparatus to interleave bits across symbols from different constellations
An encoded input bit stream is interleaved across a number of symbols having different bit sizes in a manner that ensures that the bits assigned to each symbol from the bit stream are separated by a minimum separation. In this manner, bits that are adjacent within the bit stream do ...

03/23/06 - 20060062318 - Method for the spectral configuration of signals modulated by means of orthogonal frequency division multiplexing (ofdm) for an electrical network
It is characterized in that, maintaining the sampling frequency of the digital-analog converter of the transmitter and the analog-digital converter of the receiver, the bandwidth, the spectral position of the OFDM signal, the shape of the spectrum of the OFDM signal that is transmitted, the level of the spectrum of ...

03/23/06 - 20060062317 - Apparatus and method for frequency synchronization in ofdm system
A method and apparatus are provided for frequency synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) system, wherein the method includes the steps of transmitting OFDM symbols in such a manner that a data symbol size of a particular OFDM symbol in each frame is set to be smaller than ...

03/23/06 - 20060062316 - Frequency recovery apparatus and method for use in digital broadcast receiver
A frequency recovery apparatus and method for use in a digital broadcast receiver having very strong resistance to a sampling offset is disclosed. A frequency recovery apparatus for use in a digital broadcast receiver for receiving a digital broadcast signal transmitted according to an orthogonal frequency division multiplexing (OFDM) scheme, ...

03/23/06 - 20060062315 - Method and apparatus for encryption of over-the-air communications in a wireless communication system
A communication device converts a bit stream to multiple symbols and provides encryption at a physical layer by shifting a phase of each symbol of the multiple symbols to produce multiple encrypted symbols. Each encrypted symbol of the multiple encrypted symbols is modulated with an orthogonal subcarrier to produce at ...

03/23/06 - 20060062314 - Symbol interleaving
The invention relates to a method for communicating digital data using an orthogonal frequency division multiplexing (OFDM) transmission system (10) including at least one transmitter (600, 601) and receivers (700, 701). The method comprises selecting a mode of operation in a transmitter among at least one mode, each mode of ...

03/16/06 - 20060056530 - Receiving method and apparatus, and communication system using the same
A radio unit receives burst signals in a target system or those in a MIMO system. A judgment unit determines if a MIMO signal having a form of channel corresponding to the target system is assigned posterior to a target LTS and a target signal. If a constellation of signal ...

03/16/06 - 20060056529 - Method and system for optimization of channel estimation and synchronization in an ofdm-mimo wireless communication system
The present invention is related to a method and system for optimization of channel estimation and synchronization in an Orthogonal Frequency Division Multiplexing (OFDM) Multiple-Input Multiple-Output (MIMO) wireless communication system. In accordance with the present invention, all of the training sequences are simply constructed based on a basic code by ...

03/16/06 - 20060056528 - Method of transmitting and receiving preamble sequences in an orthogonal frequency division multiplexing communication system using multiple input multiple output scheme
A method of transmitting and receiving preamble sequences in a transmitter in an OFDM communication system is provided. A transmitter segments a first sequence of a predetermined length into a predetermined number of second sequences, generates as many preamble sequences as the second sequences by applying different time offsets to ...

03/16/06 - 20060056527 - Adaptive bit/power loading technique for a multicarrier communication system
A bit/power loading method in an adaptive modulation-based multicarrier communication system computes ratios of modulation mode values to transmission power values sub-channel-by-sub-channel, selects a combination of sub-channels in which a sum of the ratios is maximized for a total number of bits to be simultaneously transmitted, and transmits signals in ...

03/16/06 - 20060056526 - Allocating data between tones in a vdsl system
A new protocol is proposed for transmission of data through lines such as telephone lines. The tones of a signal are associated into groups 10, 11, and tone ordering, gain selection, and/or bit swapping within the processing system are done within the members of a group 10, 11. This idea ...

03/16/06 - 20060056525 - Computationally efficient protocols for vdsl system
Techniques which reduce the computational burden of the IFFT/FFT section of a DSL data transmission/reception apparatus, taking into account the nature of conventional IFFT/FFT algorithms. These algorithms operate using “butterflies” representing complex calculations performed on input values. The butterflies are here referred to as “simple” if all the input values ...

03/16/06 - 20060056524 - Apparatus and method for providing digital broadcasting service based on multiple broadcasting sites and frequency bands
An apparatus for transmitting data in a digital broadcasting system is disclosed. The apparatus includes: a source encoding unit for encoding data to be transmitted and generating source-coded data; a capacity managing unit for dividing the source-coded data into divided data for a plurality of channels in case that an ...

03/09/06 - 20060050802 - Channel estimation method in a mimo wireless communication system
A channel estimation method in a Multiple Input Multiple Output (MIMO) mobile communication system having a plurality of transmission antennas and a plurality of reception antennas is provided. In a method of transmitting, by a transmitter, channel estimation signals for channel estimation at a receiver, the transmission antennas transmit the ...

03/09/06 - 20060050801 - Synchronisation in a receiver
A radio receiver is suitable for use in an OFDM wireless communications system, in which it is necessary to identify a timing point at a start of a frame. In order to ensure optimum performance of the receiver in multipath environments, it should be synchronised with the first received multipath ...

03/09/06 - 20060050800 - Packet detection in time/frequency hopped wireless communication systems
Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver ...

03/09/06 - 20060050799 - Transmission and reception of reference preamble signals in ofdma or ofdm communication systems
Techniques for generating preamble sequences for OFDM and OFDMA communication systems based on CAZAC sequences with desired properties of constant amplitudes (CA) and zero autocorrelation (ZAC). Such preamble sequences may be used for synchronization and identification of individual transmitters. For example, the OFDMA symbol is constructed using a CAZAC sequence ...

03/02/06 - 20060045195 - Apparatus and method for estimating a signal power to interference power ratio in a wireless communication system
A transmission and reception apparatus and method for use in a wireless communication system, and an apparatus and method for adaptively transmit and receive a signal according to channel state in a wireless communication system. An apparatus for adaptively performing transmission according to a state of a channel transmitted from ...

03/02/06 - 20060045194 - Method for estimating wireless channel parameters
Method for the estimation of channel parameters in a wireless communication system. In accordance with the method several levels of the wireless channel parameters estimation take place to address the specific requirements of the channel. Based on the level of estimation required an appropriate estimation algorithm is selected to achieve ...

03/02/06 - 20060045193 - System, transmitter, method, and computer program product for utilizing an adaptive preamble scheme for multi-carrier communication systems
A system, transmitter, method, and computer program product apply a performance improvement characteristic, such as phase rotation or power allocation, to both a known preamble and a data payload of a transmitted data packet, such that existing multi-carrier receivers are capable of decoding the data payload with the performance improvement ...

03/02/06 - 20060045192 - Method and apparatus for pilot channel transmission and reception within a multi-carrier communication system
In a communication system where data is transmitted on k sub-carriers and N pilot channels are averaged for coherent demodulation, k+N−1 pilot channels are broadcast on the k sub-carriers. In a first embodiment a first and a last plurality of sub-carriers comprise the additional N−1 pilot channels being broadcast at ...

02/23/06 - 20060039491 - Frequency recovery apparatus and mobile broadcast receiver using the frequency recovery apparatus
A frequency recovery apparatus and a mobile broadcast reception system utilizing the frequency recovery apparatus are disclosed. The frequency recovery apparatus and the mobile broadcast receiver estimate a fractional frequency offset value using I and Q components of a correlation value of a guard interval and compensate for the estimated ...

02/23/06 - 20060039490 - Systems and methods for implementing receiver transparent q-mode
In a receiver transparent Q-mode, i.e., a Q-mode that is only implemented by a transmitter, the receiver is unaware of the Q-mode state of the transmitter. In this type of Q-mode configuration, the transmitter could enter and exit Q-mode as desired while the receiver, could, for example, continue to function ...

02/23/06 - 20060039489 - Method and apparatus for providing closed-loop transmit precoding
A method for providing closed-loop transmit precoding between a transmitter and a receiver, includes defining a codebook that includes a set of unitary rotation matrices. The receiver determines which preceding rotation matrix from the codebook should be used for each sub-carrier that has been received. The receiver sends an index ...

02/23/06 - 20060039488 - Channel estimator and related method for smoothing channel responses of a multi-carrier system
A channel estimator and a related method for smoothing channel responses of a multi-carrier system. The channel estimator includes a channel response computing circuit for computing at least one of a target channel estimation and a reference channel estimation by utilizing a computing algorithm, wherein the target channel estimation and ...

02/23/06 - 20060039487 - Clocking architectures in high-speed signaling systems
Clocking systems and methods are provided below that accurately clock per-pin data transfers of input/output (IO) circuits of integrated circuit devices. These multiplexer-based clock selection systems use a dedicated multiplexer to receive clock signals from multiple mixer circuits and in turn to provide a selected reference clock signal for use ...

02/23/06 - 20060039486 - Dsl data collection system
Information is sent by a DSL system component using a non-disruptive operational data parameter. One or more bits of the non-disruptive operational data parameter are used to send other information. In some instances the selected parameter will be an unused parameter, such as an unused fast operational mode or interleaved ...

02/23/06 - 20060039485 - Pattern position measuring device, method, and program, and record medium on which the program is recorded
The position of a specific pattern such as known symbol in a signal such as an OFDM signal is estimated with high accuracy. An effective symbol extraction section (12) extracts a known symbol (preamble) as an effective symbol from a signal to be measured according to an approximate position of ...

02/16/06 - 20060034380 - Channel estimation for wireless systems with multiple transit antennas
In various embodiments, techniques are provided to determine channel characteristics of various communication systems such as OFDM systems or systems using a plurality of transmit antennas by using various sets of training symbols. ...

02/16/06 - 20060034379 - Synchronization method and related apparatus of an ofdm digital communication system
A synchronization method and related apparatus of an OFDM digital communication system are disclosed for determining a position of a synchronization byte in a received signal. The method includes extracting a transmission parameter signal (TPS) from the received signal, determining a symbol number and a frame number corresponding to a ...

02/16/06 - 20060034378 - Papr reduction
Method of communicating frames of digital data by OFDM modulated signals comprising a first plurality of payload carrying sub-channels and a second plurality of pilot carrying sub-channels, whereby consecutive frames of payload data is are associated with a given pilot configuration and transmitted. Prior to the transmission of a frame ...

02/09/06 - 20060029144 - Frequency domain equalization
A radio receiver 102 is provided. The radio receiver 102 comprises one or more data Fast Fourier Transformers, each data Fast Fourier Transformer operable to perform a Fast Fourier Transform on an input data block, one or more impulse response Fast Fourier Transformers, each impulse response Fast Fourier Transformer operable ...

02/09/06 - 20060029143 - Ofdm system receiver apparatus suppressing inter-symbol interference
An receiver apparatus according to an OFDM system includes a inter-symbol interference suppressing unit configured to modify to a predetermined content a portion of a dominant wave included in a received signal and to modify to a predetermined content a portion of at least one delayed wave included in the ...

02/09/06 - 20060029142 - Simplified narrowband excision
An improved ingress cancellation filter comprising a Fast Fourier Transform circuit which replaces the analysis filter bank of the prior art to break the incoming signal down into sub bands, an ingress cancellation filter that weights each sub band based upon the probability that the sub band is corrupted by ...

02/02/06 - 20060023801 - Versatile system for optimizing transmit diversity in wireless communications
The present invention provides a versatile system for optimizing pilot pattern diversity in a digital communications system—particularly in multiple antenna OFDM communications systems. According to the present invention, a receiving device within a communications system may receive transmissions from a first transmitting device (202) and a second transmitting device (204), ...

02/02/06 - 20060023800 - Ofdm signal demodulator circuit and ofdm signal demodulating method
When an OFDM demodulator circuit performs the waveform equivalence of carrier signals outputted from an FFT processing circuit, the OFDM demodulator circuit extracts correction coefficients corresponding to the gain of a reception signal outputted from a tuner unit from a correction coefficient table, and phase corrections are performed in a ...

02/02/06 - 20060023799 - Apparatus for channel equalization and method thereof
Channel Equalization of a digital TV is disclosed. In channel equalization for restoring an original signal from a digital TV reception signal having passed through a channel, the present invention includes estimating an impulse response of the channel from a received signal having passed through the channel using conjugate-gradient algorithm, ...

02/02/06 - 20060023798 - System, modem, receiver, transmitter and method for improving transmission performance
A system, modem, receiver, transmitter and method for improving transmission performance. A coefficient may be calculated using a received signal. A process may be performed on at least one data packet scheduled for transmission based on the calculated coefficient. The process may improve transmission performance. ...

01/26/06 - 20060018395 - Systems and methods for a multicarrier modulation system with a variable margin
A multicarrier modem has a plurality of carriers over which data is transmitted. By assigning, foe example, one or more different margins to the individual carriers the data rate and impairment immunity can be increased. ...

01/26/06 - 20060018394 - Pilot tones in a multi-transmit ofdm system usable to capture transmitter diversity benefits
In a wireless transmitter having a plurality of spatial streams differentiable at a receiver, wherein data is encoded and transmitted over a communication channel with pilot tones to provide the receiver with information about the effects of the communication channel and/or transmitter impairments and/or receiver impairments on the spatial streams ...

01/26/06 - 20060018393 - Frequency domain filtering to improve channel estimation in multicarrier systems
A channel estimation system comprises a filtering component that selectively scales a plurality of carriers as a function of location of the plurality of carriers within a frequency band, wherein the plurality of carriers comprises at least one data carrier and at least one pilot carrier. A component thereafter extrapolates ...

01/26/06 - 20060018392 - Intelligent array radio architecture
A receiver sets weights for an antenna array according to a series of algorithms including an energy algorithm, a least squares algorithm and a least mean square algorithm. ...

01/26/06 - 20060018391 - Method and apparatus of detecting isi/icsi in an ofdm system
A method for detecting inter-carrier-symbol interference (ICSI) in an OFDM system includes the steps of computing a first correlation value representing the correlation between at least one of first signals of a first symbol and at least one of second signals of a second symbol previous to the first symbol, ...

01/26/06 - 20060018390 - Method and apparatus of detecting isi/icsi in an ofdm system
A method for detecting inter-symbol interference (ISI) in an OFDM system includes the steps of computing a first correlation value representing the correlation between a plurality of first signals of a first symbol and a plurality of second signals of a second symbol previous to the first symbol, wherein the ...

01/19/06 - 20060013327 - Apparatus for antenna diversity using joint maximal ratio combining
A transceiver using composite beamforming technique is provided wherein a first communication device has a plurality of antennas and the second communication has a plurality of antennas. When the first communication device transmits to the second communication device, the transmit signal is multiplied by a transmit weight vector for transmission ...

01/19/06 - 20060013326 - Propagation path estimation method and apparatus
In estimating propagation path in an OFDM receiver in an OFDM communication system, a CIR estimation unit estimates a group of impulse responses of a propagation path, a valid-impulse discriminator selects impulse responses (CIR), which are greater than a predetermined threshold value, from the impulse-response group, and a propagation path ...

01/19/06 - 20060013325 - Wireless communication system with configurable cyclic prefix length
To transmit data in a manner to mitigate the deleterious effects of delay spread, the expected coverage areas for multiple transmissions to be sent in multiple time slots are initially determined. Cyclic prefix lengths for these transmissions are selected based on the expected coverage areas. The cyclic prefix length for ...

01/12/06 - 20060008018 - Vofdm receiver correlation matrix processing using factorization
Vector orthogonal frequency division multiplexing (VOFDM) receiver correlation matrix processing using factorization. Efficient correlation matrix processing is used to combine multiple signals into a single combined signal. This single combined signal may be viewed as being a beam form soft decision. An efficient square root factorization system and method provides ...

01/12/06 - 20060008017 - Time-domain windowing of multi-band ofdm system to enable spectral sculpting
A method of wirelessly communicating is disclosed. The method comprises generating a plurality of tones for a wideband orthogonal frequency division multiplex symbol (310), the tones including a plurality of contiguous zero-valued tones, inverse Fourier transforming the tones to a plurality of time-domain samples (312), copying a plurality of the ...

01/12/06 - 20060008016 - Ultra wideband interference cancellation for orthogonal frequency division multiplex transmitters by protection-edge tones
A method of wirelessly communicating is disclosed. The method comprises determining a matrix W based in part on limiting a plurality of active interference cancellation tone values (416), determining the active interference cancellation tone values (416) based on W and based on a plurality of information data values (410), and ...

01/12/06 - 20060008015 - Method and apparatus for reducing the dynamic range of a radio signal
In a method for reducing the dynamic range of a multicarrier transmission signal (12′) which is formed in a transmitter and is composed of two or more carriers, the various signal structure timings of the carriers are determined. A delay unit (100; D0, D1, . . . , DN−1) is ...

01/12/06 - 20060008014 - Method and adaptive modulation in multi-carrier communication
In a radio-communication system and a radio station, one or more subcarriers are grouped, and the maximum bit number per symbol of the modulation method used for each subcarrier is determined for each group and shared between a transmitting station and a receiving station. The transmitting station divides and allocates ...

01/05/06 - 20060002486 - Advanced mimo interleaving
A MIMO transmitter including an interleaving system for parsing encoded bits to a plurality of spatial streams and a plurality of interleavers to interleave bits for spatial streams such that at least a first spatial stream uses a first stream interleaver that interleaves with a pattern distinct from a second ...

01/05/06 - 20060002485 - Systems and methods for rapid signal detection and identification
The present invention comprises systems, methods, and devices for detecting the presence of a specified signal type by autocorrelating the signal with a time-delayed copy of itself, by simultaneously crosscorrelating the signal with an expected signal type, and by then comparing the results of the autocorrelation and crosscorrelation to determine ...

12/29/05 - 20050286649 - Using multiple pilot signals for timing error estimation in digital subscriber line communications
A receiving modem (20) including functionality for adjusting the synchronization of its timing relative to a transmitting modem (10), by recovering timing from a plurality of pilot tones transmitted by the transmitting modem (10) in a multicarrier modulation signal, is disclosed. For a subset of the pilot tones, the receiving ...

12/29/05 - 20050286648 - Method and apparatus for high-order papr reduction of an ofdm signal
A method and apparatus for high-order peak-to-average power ratio reduction of an OFDM signal are disclosed. The method partitions time-domain input data x[n] of length N into M disjoint subblocks in time domain, and a complete N-point transmitted signal {tilde over (x)}[n], n=0, 1, . . . , N−1, is ...

12/22/05 - 20050281346 - Method and system of tone ordering for discrete multi-tone systems with tone grouping
The present disclosure describes a method and system of tone ordering for discrete multi-tone (DMT) systems with tone grouping. Some illustrative embodiments may include a method, comprising, dividing a plurality of sub-channels within a discrete multi-tone symbol into a plurality of groups, selecting each sub-channel of the plurality of sub-channels ...

12/22/05 - 20050281345 - Device and method for reducing peaks of a composite signal
A method of limiting at least one peak of a composite signal having multiple carriers signals involves placing energy in at least one bandwidth gap located between respective frequency bandwidths of carrier signals. ...

12/15/05 - 20050276344 - Coding scheme for a wireless communication system
Coding techniques for a (e.g., OFDM) communication system capable of transmitting data on a number of “transmission channels” at different information bit rates based on the channels' achieved SNR. A base code is used in combination with common or variable puncturing to achieve different coding rates required by the transmission ...

12/15/05 - 20050276343 - Rate adaptation and parameter optimization for multi-band single carrier transmission
A method for enhancing the bit rate and/or margin at which quadrature amplitude modulation (QAM) communication is performed over multiple bands of a communication link includes the steps of varying a spectral allocation and constellation size with which communication is performed, so as to define a combination of spectral allocation ...

12/15/05 - 20050276342 - Architecture for a digital subscriber line analog front end
An analog front end for communicating discrete multitone modulated signals on a subscriber line includes a transmit block, a receive block, and a hybrid packaged within a same integrated circuit. Upstream data to be transmitted to the subscriber line is pre-processed to eliminate even images. A power spectral density shaping ...

12/15/05 - 20050276341 - Method and apparatus for transmitting and/or receiving data
A method and an apparatus for transmitting data is described. The data is modulated onto a plurality of carriers. At least one data element of the data is modulated onto at least two different carriers of the plurality of carriers. This technique presents an easy way to transmit data over ...

12/15/05 - 20050276340 - Method and system for determining symbol boundary timing in a multicarrier data transmission system
Improved techniques for acquiring symbol boundary timing at a receiver of a multicarrier data transmission system during a training sequence are disclosed. One aspect is symbol boundary determination at a receiver wherein minimal interference is used as a criterion in selecting from a plurality of potential symbol boundary timings. The ...

12/15/05 - 20050276339 - Training sequence for symbol boundary detection in a multicarrier data transmission system
An improved training sequence for acquiring symbol boundary timing at a receiver of a data transmission system is disclosed. One aspect pertains to an improved training sequence wherein groups of identical symbols are transmitted by a transmitter. These symbols can be supplied to the transmitter in a time domain or ...

12/15/05 - 20050276338 - Training sequence for channel estimation in a data transmission system
An improved training sequence for estimating a channel (e.g., channel impulse response) in the time domain is disclosed. The improved training sequence enables time-domain estimation and eliminates the need for correct frequency-domain channel estimation at every frequency. By utilizing the training sequence according to the invention, estimation of each of ...

12/15/05 - 20050276337 - Bandwidth efficient orthogonal frequency division multiplexing communication system
In an OFDM communications system, cyclic prefix and postfix samples are used to improve the reliability of a received OFDM symbol. Typically, the prefix and postfix extensions are merely repeated portions of the OFDM symbol that are ordinarily discarded during the decoding process. In the instant invention, the cyclic prefix ...

12/15/05 - 20050276336 - Multiplexing scheme for an orthogonal frequency division multiplexing system
A method is provided for controlling transmissions between a base station and a mobile station in a wireless system using a plurality of subcarriers. A subcarrier allocation scheme is proposed where a total scheduling interval is divided into at least two sub-intervals. In a first interval, data transmission takes place ...

12/15/05 - 20050276335 - Generalized polyphase channelization system
A computation efficient polyphase channelization system enables one of many user FDMA signals to be channelized through multiple FFT response frequency bands forming an aggregate frequency band where K-point FFT channels are greater than the decimation factor M to produce FFT overlapped responses that have a smooth aggregate response without ...

12/08/05 - 20050271155 - Ofdm interference cancellation based on training symbol interference
Systems and methods for optimally combining signals from multiple antennas to ameliorate the effects of noise and/or interference on OFDM communications are provided. In one embodiment, an initial spatial statistical characterization of interference and/or noise is based on training symbols received via each antenna. Because the transmitted values of the ...

12/08/05 - 20050271154 - System for allocating radio resources in multiband ofdm system
A method for seamlessly receiving a symbol from a transmitting end at a receiving end even when error occurs in a certain radio resource of a multiband OFDM system that transmits a same symbol at least two times. The multiband OFDM system includes a transmitting end selecting two radio resources ...

12/08/05 - 20050271153 - Communication quality controller and a communication quality control method
A communication quality controller can avoid, when periodically changing noise is abruptly occurring, disconnection of a communication line used for data communication and prevent resetting of a link speed for the data communication. During the data transmission at a beforehand set link speed, a CRC error counter monitors for a ...

12/08/05 - 20050271152 - Fbm-based multiple access technique
Disclosed is a multicarrier-based wireless communication system including a base station for providing a multiple access service to terminals which filter multitone transmitting signals through filters and transmit the filtered signals. A transmitter of the respective terminals includes a multiplexer for multiplexing an input signal and outputting the signal as ...

12/08/05 - 20050271151 - Boundary tracking apparatus and related method of ofdm system
A boundary tracking method applied in an OFDM receiver includes generating a plurality of demodulated signal sets corresponding to part of sub-carriers of a packet according to different boundaries with different positions located at the packet, determining the most precise one of the boundaries according to a plurality of inter-symbol ...

12/01/05 - 20050265469 - Multiple transmit antenna interleaver design
An arrangement of interleavers allocates bits from an input symbol across sub-symbols transmitted via sub-carriers of multiple orthogonal frequency division multiplex (OFDM) carriers. The input bits are allocated in a fashion to provide separation across subcarriers, and rotation of sub-symbols across the OFDM carriers provides additional robustness in the present ...

12/01/05 - 20050265468 - Transmitter and transmission controlling method
An OFDM transmitter (100) is disclosed. The OFDM transmitter comprises: a sorter (103-1) for sorting plural input complex signals and partitioning them into plural groups; plural IFFTs (103-2) for performing inverse Fourier transform on the input complex signals in groups; a peak reducer (103-4) for performing peak reduction, based on ...

12/01/05 - 20050265467 - Intercarrier interference cancellation algorithm
A method comprising wirelessly transmitting and receiving a data signal in an orthogonal frequency division multiplexing (OFDM) system. The method further comprises, in the frequency domain, at least partially removing overlap between a first received subcarrier frequency data and a second received subcarrier frequency data. ...

12/01/05 - 20050265466 - Adaptive channel estimation method used in multi-carrier communication system
An adaptive channel estimation method utilized in a multi-carrier communication system. The communication system transmits a symbol through a plurality of subchannels. The plurality of subchannels includes a plurality of pilot signal subchannels and a plurality of data signal subchannels. The pilot signal subchannels transmit a plurality of pilot signals ...

12/01/05 - 20050265465 - Mimo decoding
In MIMO wireless communications employing LMMSE receiver, the symbols transmitted through a transmit antenna are estimated at the receiver in the presence of interference consisting of two main components: one due to the additive noise and the other due to (interfering) symbols transmitted via the remaining antennas. This has been ...

12/01/05 - 20050265464 - Method for initializing the computation of a quasi-periodic steady state of a multi-tone system
The invention refers to a method for initializing the computation of a quasi-periodic steady state of a multi-tone system, and to a computer program product for carrying out such a method. The method for initializing the computation of a quasi-periodic steady state of a multi-tone system comprises the following steps: ...

11/24/05 - 20050259761 - Communication start-up with variant spectral density mask
A method is provided for initiating communications over a channel between a transmitter and a receiver within a specified spectral range, subject to a mask to be applied at the transmitter so as to attenuate at least one segment of the spectral range. The method includes providing to the receiver ...

11/24/05 - 20050259760 - Method and apparatus for excision of narrowband interference signals in navigation or communication bands
A narrowband interference excision and nulling system for Global Positioning Satellite (GPS), spread spectrum navigation and communication bands, and an antijam electronic apparatus that operates using RF conversion and digital signal processing. A band containing the signal of interest as well as interference is converted to an intermediate frequency (IF) ...

11/24/05 - 20050259759 - Transmitting device, transmitting method, and storage medium
Disclosed is a method that preferably performs transmission processing to a time sequence signal of a known pattern as the pre-amble and an OFDM transmitted signal. In data communications, the general practice defines the pre-amble and detects the peaks of the mutual correlation to thereby detect synchronization. The pre-amble here ...

11/24/05 - 20050259758 - Multi-carrier ofdm uwb communications systems
The present invention, generally speaking, provides for signaling methods in which multiple sub-bands of a transmission band are continuously occupied by an OFDM signal that would otherwise occupy only a single sub-band. In accordance with one embodiment, steps include producing an OFDM symbol; transforming the OFDM symbol to produce an ...

11/24/05 - 20050259757 - Frequency domain equalization in communications systems with scrambling
A method of, and system for applying frequency-domain equalization in a DS-CDMA system, either by augmenting the transmitted data block before it is scrambled by appending a prefix and a suffix known to or knowable by the receiver or by augmenting the transmitted data block after it is scrambled but ...

11/17/05 - 20050254589 - Channel estimation device, channel estimation method, and wireless receiver
A channel estimation device is provided to achieve high-precision channel estimation in a MIMO or multicarrier wireless receiver. This channel estimation device is used in the wireless receiver that receives pilot signals through reception antennas. The pilot signals are modulated by a multicarrier method and are transmitted from transmission antennas. ...

11/17/05 - 20050254588 - Digital signal encoding method and apparatus using plural lookup tables
A digital signal encoding method and apparatus using a plurality of lookup tables. The method includes: preparing a plurality of lookup tables storing numbers of allocated bits for encoding frequency bands of an input signal according to a characteristic of the input signal in a predetermined number of addresses; dividing ...

11/17/05 - 20050254587 - Transmitting and receiving apparatuses for reducing a peak-to-average power ratio and an adaptive peak-to-average power ratio controlling method thereof
Transmitting and receiving apparatuses for PAPR reduction and an adaptive PAPR control method thereof are provided. Prior to transmission, the transmitting apparatus limits the peak of a multi-carrier modulated signal using a mapping function that increases an output value with an input value and converges the output value to a ...

11/10/05 - 20050249298 - Multi-code multi-carrier code division multiple access (cdma) system and method
A multi-code multicarrier CDMA system and method for communicating data by transforming a stream of data into a plurality of code sequences selected from a code book by associating symbols of the data stream with the code sequences of the code book, wherein the codebook includes M code sequences and ...

11/10/05 - 20050249297 - Configuration dsl transceiver
A DSL modem (21) including a configurable digital transceiver (30) is disclosed. The digital transceiver (30) includes a configuration register (43), or other circuitry, that selects a number of analog transmission ports to be implemented in the modem (21). Instances of analog front-end circuitry (34) for each of the configured ...

11/10/05 - 20050249296 - Incremental redundancy operation in a wireless communication network
The invention is based on the recognition that optimal or at least improved performance can be obtained by providing relevant information that enables selection of which sub-block to set forth for transmission from the transmitting side to the receiving side. The idea according to the invention is to measure, for ...

11/03/05 - 20050243940 - Method and apparatus for generating preamble sequence for adaptive antenna system in orthogonal frequency division multiple access communication system
Disclosed is a method and an apparatus for generating a preamble sequence for an adaptive antenna system supporting a space division multiple access in an OFDMA communication system. Particularly, disclosed is a method for forming a preamble sequence identifying each of a plurality of mobile subscriber stations located within a ...

11/03/05 - 20050243939 - Pilot designing method in an uplink ofdma system
A pilot designing method in an uplink OFDMA system is provided. In the uplink OFDMA system, communications are carried out in a frame divided into time-frequency lattices, and each time-frequency lattice includes a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to ...

11/03/05 - 20050243938 - Multicarrier modulation systems
The invention provides a new approach which is better suited to FFT design as applied to multicarrier modulation systems such as OFDM. The signals are scaled so that overflow, rather than being completely avoided, occurs with low probability throughout the IFFT and FFT structures. The size of the error that ...

11/03/05 - 20050243937 - Determination of the time delay and/or power of a multicarrier signal
The invention relates to a method of determining the time shift and/or the power of a received signal incorporating a reference sequence (3) and transmitted by multicarrier modulation on a set (M) of carriers spaced from each other by a distance nΔf where n is a natural integer and Δf ...

10/27/05 - 20050238110 - Apparatus and method for reducing peak-to-average power ratio in orthogonal frequency division multiplexing communication system
Provided is a method for reducing a PAPR (Peak-to-Average Power Ratio) of a transmit signal in a broadband wireless communication. The method includes the steps of: assigning information signals to remaining tones except L reserved tones that are previously appointed among N tones, and performing an IFFT operation on the ...

10/27/05 - 20050238109 - Communication apparatus and communication method using digital wavelet multi carrier transmission system
When a pilot carrier is provided in data transmission according to the DWMC transmission system, continuous identical data are given in a sub-carrier pair having predetermined adjacent two sub-carriers as a unit in plural sub-carriers on a frequency axis, whereby pilot carriers P1, P2, . . . to be sine ...

10/27/05 - 20050238108 - Apparatus and method for switching between an amc mode and a diversity mode in a broadband wireless communication system
An apparatus and method for switching between an AMC mode and a diversity mode adaptively according to a channel environment in a broadband wireless communication system are provided. According to the present invention, a transmitter (a base station) determines a transmission mode according to frequency-domain and time-domain channel measurement information ...

10/13/05 - 20050226341 - Decision feedback channel estimation and pilot tracking for ofdm systems
Current OFDM systems use a limited number of symbols and/or sub-channels to provide approximations for channel estimations and pilot tracking, i.e. phase estimations. For example, two training symbols in the preamble of a data packet are used to provide channel estimation. Four of the fifty-four sub-channels are reserved for providing ...

10/06/05 - 20050220202 - Method for seamlessly changing power modes in an adsl system
A DMT system and method with the capability to adapt the system bit rate on-line in a seamless manner. The DMT system provides a robust and fast protocol for completing this seamless rate adaptation. The DMT system also provides a framing and encoding method with reduced overhead compared to conventional ...

10/06/05 - 20050220201 - Methods and apparatus for determining minimum cyclic prefix durations
Methods and apparatus for generating and transmitting frequency division multiplexed signals are described. Each transmitted FDM signal is generated by combining, e.g., multiplexing, a plurality of individual analog subcarrier signals together. Individual analog subcarrier signals are generated by processing one or more digital signals, e.g., symbols plus a cyclic prefix ...

10/06/05 - 20050220200 - Bandwidth and power efficient multicarrier multiple access
Techniques are described for multicarrier multiple access wireless transmission, e.g. orthogonal frequency-division multiple access (OFDMA) transmissions, over frequency selective fading channels. The techniques are designed to maintain constant modulus transmissions for uplink while effectively mitigating intersymbol interference. Specifically, the techniques utilize non-redundant unitary precoding across OFDMA subcarriers to maintain constant ...

10/06/05 - 20050220199 - Ofdm system with per subcarrier phase rotation
Subcarrier phase rotation is implemented in an OFDM transmitting apparatus to overcome problems such as, for example, non-frequency selective multipath fading. In at least one embodiment, subcarrier phase rotation is practiced in an OFDM system implementing multiple input multiple output (MIMO) techniques. ...

09/29/05 - 20050213680 - Receiver
A receiver for recovering data from a symbol of signal samples generated in accordance with Orthogonal Frequency Division Multiplexing is described. The symbol may be a COFDM symbol in accordance with the DVB-T standard, and includes pilot carrier signals for use in estimating channel conditions. The receiver includes a pilot ...

09/29/05 - 20050213679 - Receiver
A receiver for recovering data from a received symbol of signal samples generated in accordance with Orthogonal Frequency Division Multiplexing (OFDM) includes a pilot assisted channel estimator operable to generate an estimate of a transmission channel through which the received OFDM symbol has passed. The OFDM symbol includes pilot signals ...

09/29/05 - 20050213678 - Tracking system comprised in an ofdm receiver
A tracking system comprises a frequency correction means operable to correct a frequency error of a received OFDM symbol. The tracking system also comprises a to the frequency correcting means connected transforming means, operable to perform a Fourier transform operation resulting in a number of independently modulated subcarriers, an to ...

09/29/05 - 20050213677 - Apparatus and method for allocating ovsf codes and i/q channels for reducing peak-to-average power ratio in transmitting data via enhanced up-link dedicated channels in wcdma systems
The present invention supposes a situation in which an Enhanced Uplink Dedicated transport Channel (EUDCH) is used in a Wideband Code Division Multiple Access (WCDMA) system. In a user equipment (UE), when physical channels for transmitting EUDCH data are transmitted in addition to existing physical channels, a Peak-to-Average Power Ratio ...

09/29/05 - 20050213676 - Periodic dmt signals with cyclic extension
A method for digital communication includes generating time-domain symbols having a predetermined symbol duration in accordance with a discrete multi-tone (DMT) modulation scheme. A cyclic extension is added to each of the time-domain symbols so as to form data blocks having a block length that is not an integer multiple ...

09/22/05 - 20050207506 - Multi-carrier signal transmitting apparatus and multi-carrier signal receiving apparatus
In transmitting first information necessary for gaining synchronism of transmission signal and second information which is the other information by determining a break of a single modulation unit with a simple structure and processing prior to Fourier transformation on the side receiving a signal transmitted as a multi-carrier signal, a ...

09/22/05 - 20050207505 - Signal transmission circuit
A method of communicating over a wideband communication channel divided into a plurality of sub-channels comprises dividing a single serial message intended for one of the plurality of communication devices into a plurality of parallel messages, encoding each of the plurality of parallel messages onto at least some of the ...

09/15/05 - 20050201477 - Apparatus and method for transmitting a sub-channel signal in a communication system using an orthogonal frequency division multiple access scheme
A method of allocating sub-channel signal interleaving patterns to BSs forming a wireless communication system that divides a frequency band into a plurality of sub-carriers and including a plurality of sub-channels, which are a set of predetermined adjacent sub-carriers. The method includes: creating a basic orthogonal sequence having a length ...

09/15/05 - 20050201476 - Method and apparatus for allocating subcarriers in a broadband wireless communication system using multiple carriers
A method and apparatus for efficiently allocating subcarriers for data and/or a control signal requiring frequency diversity within the same symbol and for data or a control signal which needs to be transmitted in a frequency band with successive subcarriers, so as to transmit the signals simultaneously, satisfying the different ...

09/15/05 - 20050201475 - Cofdm demodulator
A COFDM demodulator including a fast Fourier transform circuit receiving a signal on an information channel, the received signal corresponding to a sequence of symbols, each conveying several carriers, some of which are pilots, each carrier of a symbol being modulated in phase and/or in amplitude by a current complex ...

09/15/05 - 20050201474 - Method and apparatus for transmitting channel quality information in an orthogonal frequency division multiplexing communication system
A method and apparatus for efficiently transmitting channel quality information in an OFDM communication system using dynamic channel allocation and adaptive modulation, and determining parameters required for time-division channel quality information transmission in an asynchronous CDMA communication system are provided. In the OFDM communication system in which a plurality of ...

09/15/05 - 20050201473 - Systems and methods for receiving data in a wireless communication network
A method of communicating over a wideband communication channel divided into a plurality of sub-channels comprises dividing a single serial message intended for one of the plurality of communication devices into a plurality of parallel messages, encoding each of the plurality of parallel messages onto at least some of the ...

09/08/05 - 20050195910 - Method and apparatus for allocating subcarriers in a broadband wireless communication system using multiple carriers
A method and apparatus for allocating subcarriers in a broadband wireless communication system using multiple carriers are provided. In the wireless communication system where the total available frequency band is divided into a plurality of subcarriers and subchannels each are formed with a predetermined number of subcarriers, the subcarriers are ...

09/08/05 - 20050195909 - Method for allocating a subchannel in an orthogonal frequency division multiple access cellular communication system
A method for allocating a subchannel in a transmitter of an Orthogonal Frequency Division Multiple Access (OFDMA) cellular communication system in which an entire frequency band includes a plurality of bands, each of the bands includes a plurality of bins, and each of the bins includes a plurality of subcarriers. ...

09/08/05 - 20050195908 - System and method for adaptive modulation
A wireless communication system is configured for adaptive modulation of a transmitted symbol. The specific modulation and/or coding is uniquely identified and data related thereto is embedded within the transmitted symbol. A receiver extracts pilot signals form the transmitted symbol and performs a correlation analysis to identify the particular modulation/coding ...

09/08/05 - 20050195907 - Vdsl protocol with low power mode
A VDSL system is proposed which operates in a selected one of at least two modes. In one of those modes the volume of data that is to be transmitted is reduced. The invention proposes that this is done in such a way as to reduce the IFFT/FFT computational burden, ...

09/08/05 - 20050195906 - Low peak-to-average ratio preamble, and associated method, for packet radio communication system
Apparatus, and an associated method, for facilitating communications is a packet radio communication system, such as an IEEE 802.15.3a-compliant communication system. A deterministic sequence is used as a channel estimation sequence. The channel estimation sequence exhibits a peak-to-average ratio of lower than 8.86 dB. ...

09/08/05 - 20050195905 - System and method for adaptive bit loading source coding via vector quantization
A communication system includes a data transmitter and a data receiver in which the data transmitter transmits data using a multicarrier modulation, such as an OFDM modulation technique. The data receiver determines a predetermined level of modulation for at least one carrier of the multicarrier modulation corresponding to a received ...

09/01/05 - 20050190848 - Ofdm transceiver apparatus
In an OFDM transmitter apparatus for transmitting transmit signals, which are output from first and second OFDM transmit circuits, utilizing two mutually orthogonal polarized waves, a single carrier wave generator is provided in common for the OFDM transmit circuits, and a frequency converter in each OFDM transmit circuit multiplies a ...

09/01/05 - 20050190847 - Demodulation and modulation circuit and demodulation and modulation method
A demodulation circuit and a demodulation method can optimize sampling timing with achieving reduction of power consumption. A preliminarily known signal is inserted in the digital transmission signal upon transmission. The demodulation circuit includes A/D converting means for performing A/D conversion of a base band signal obtained by demodulation of ...

08/25/05 - 20050185726 - Multicarrier transmission system with low power sleep mode and rapid-on capability
A muticarrier transceiver is provided with a sleep mode in which it idles with reduced power consumption when it is not needed to transmit or receive data The full transmission and reception capabilities of the transceiver are quickly restored when needed, without requiring the full (and time-consuming) initialization commonly needed ...

08/25/05 - 20050185725 - Ofdm communication system and method
A transmitter (200) used in a wireless communication system based on an orthogonal frequency division multiplexing (OFDM) scheme includes a determination unit (216) configured to determine a spreading factor and an amplitude for a control channel based on at least one of signal quality information and interference information in data ...

08/25/05 - 20050185724 - Method and apparatus providing time domain interpolated channel estimation with advanced noise suppression for multicarrier transmissions
Disclosed is an interpolation procedure for channel estimation that is based on minimum mean-squared error (MMSE) estimates over comb-type pilot signals. The time domain (TD) interpolated channel estimation suppresses, by the use of an advanced noise suppression scheme, the noise jitter that spreads over all or substantially all of the ...

08/25/05 - 20050185723 - Peak suppression of multi-carrier signal with different modulation
A technique for peak suppression, phase and amplitude equalizer of multi-carrier signals with different modulation is described. The input to the multi-carrier power amplifier is modified by a peak suppression, phase and amplitude equalizer circuit prior to being applied to the amplifier. The peak suppression is applied to a multi-carrier ...

08/18/05 - 20050180519 - Digital subscriber line driver
A digital subscriber line (DSL) driver allows a transmitter to monitor its own transmit spectrum at the subscriber loop and adjust the transmit spectrum based on detected line conditions, affected by the presence of bridged taps or any other impedance variations. The transmit spectrum is preferably equalized so that all ...

08/18/05 - 20050180518 - Preamble for estimation and equalization of asymmetries between inphase and quadrature branches in multicarrier transmission systems
Distortions of radio signals transmitted in data blocks in an OFDM method, the distortions being caused by IQ asymmetries, can be estimated and subsequently equalized by means of specific reference data symbols which are transmitted at the transmitter end and may be part of a preamble. The method can be ...

08/18/05 - 20050180517 - Digital broadcast signal receiving apparatus and method
A signal receiving apparatus and method which is high in deduction accuracy of transfer characteristic and less in error rate during signal decoding. For each detection signal of a pilot carrier allotted in an OFDM symbol space, a transfer function thereof is calculated. The transfer function is subjected to two-dimensional ...

08/18/05 - 20050180516 - Symbol timing synchronization method for ofdm based communication system
A synchronization method in an OFDM based communication system. A transmitting side generates and transmits an OFDM symbol having a constant cyclic prefix, independent of time domain data symbols that are to be transmitted. A receiving side estimates a timing synchronization error based on the known cyclic prefix. Because the ...

08/18/05 - 20050180515 - Communication apparatus and communication method
There are included a transmission modulator (103) for impulse-modulating the data to be transmitted, thereby producing a subcarrier; a subcarrier control section for controlling the subcarrier to be utilized for communication, depending on the amount and significance of information and on the propagation condition of communication; and an antenna section ...

08/11/05 - 20050175114 - Wide frequency offset correction using encoded interburst phase differences
Systems and methods for wide frequency offset synchronization are provided. A synchronization data sequence is encoded onto a series of OFDM frequency domain bursts as interburst phase differences between training symbols included within the successive bursts. The interburst phase differences may also encode system configuration information. This technique may be ...

08/11/05 - 20050175113 - Digital signal demodulation of an ofdm signal with error correction
A digital signal demodulator digitizes an OFDM signal at a sampling frequency from a sampling oscillator to produce a digital OFDM signal. The digital OFDM signal is converted into I and Q components using a carrier frequency from a carrier oscillator. The IQ components are transformed into digital complex symbols, ...

08/11/05 - 20050175112 - Time domain equalization using frequency domain operations
An equalizer for a multi carrier transmission system, converts a transmitted multi carrier signal into sampled frequency domain signals, and suppresses time domain delay dispersion, on the sampled frequency domain signals. It exploits circulant decomposition of a Toeplitz matrix to enable the computationally heavy evaluation of a matrix multiplied by ...

08/04/05 - 20050169393 - Receiver device of communication system
Two correlation signals which are obtained by computing correlations between two reference signals and a reception signal are inputted to a level-0 cell, the reference signals being generated on the basis of combinations of crosstalk coefficients. A level-1 soft judgment target signal is produced by using soft judgment target signals ...

08/04/05 - 20050169392 - Efficient low-power mode for multicarrier communications
Multicarrier modulated communications, involving a transmitting modem (30; 30′) and a receiving modem (40; 40′) that operate according to normal operating mode and a low-power, quiescent, mode, are disclosed. In the quiescent mode, transmitter power is saved by scaling down the amplitude of the transmitted symbols in each frame by ...

07/28/05 - 20050163241 - Multi-carrier communication system and receiver thereof
The present invention is a multi-carrier communication system for transmitting/receiving signals via at least four sub-channels, comprising: a transmitter for transmitting data independently via the four sub-channels; a receiver comprising a receive unit disposed for each sub-channel for receiving data from a corresponding sub-channel and performing soft decision of the ...

07/28/05 - 20050163240 - Transmitting apparatus, receiving apparatus, communication system, transmission method, reception method, and communication method
A transmitting apparatus, receiving apparatus, communication system, and a signal processing method for each apply a suitable modulation method and transmission path estimation method in accordance with the characteristics of the transmission information and capable of improving the transmission efficiency. At the transmission side, the method of estimation of the ...

07/28/05 - 20050163239 - Transmitting apparatus, receiving apparatus, communication system, transmission method, reception method, and communication method
A transmitting apparatus, receiving apparatus, communication system, and a signal processing method for each apply a suitable modulation method and transmission path estimation method in accordance with the characteristics of the transmission information and capable of improving the transmission efficiency. At the transmission side, the method of estimation of the ...

07/28/05 - 20050163238 - Transceiver apparatus and transceiving method
In a transmitting method for transmitting a transmit signal sequence by a number of subcarriers, a plurality of subcarriers F1, F2, . . . FNSCH exclusively for a synchronization channel are provided, a signal sequence of synchronization channel SCH is transmitted by the plurality of exclusive subcarriers, and a common ...

07/28/05 - 20050163237 - Multi-phase carrier signal generator and multi-phase carrier signal generation method
A carrier signal generation section is provided for each of U, V, and W phases, and each of the carrier signal generation sections has an up-down counter for counting clock signals output from a clock generator. An initial value is set for each of the up-down counters. When the up-down ...

07/28/05 - 20050163236 - Transmission method and apparatus in a multiple antenna communication system
A method and apparatus are disclosed for transmitting symbols in a multiple antenna communication system. The disclosed frame structure comprises a preamble having a plurality of long training symbols that are transmitted on a plurality transmit antennas. At least a portion of the frame is delayed on at least one ...

07/28/05 - 20050163235 - Method and apparatus for improving error rates in multi-band ultra wideband communication systems
Methods, systems, and apparatus for use in a communication system utilizing multiple bands to improve transmission error rates are disclosed. Error rates are improved by mapping a portion of an input bit stream within a data stream to first and second bands of the multiple bands, transmitting the portion of ...

07/21/05 - 20050157803 - Modulating and coding apparatus and method in a high-rate wireless data communication system
An apparatus and method for determining a modulation order of packet data to be transmitted through a subcarrier in a transmission apparatus. In the apparatus and method, transmitter physical channels encode and modulate data to transmit the user data with OFDM symbols. A controller outputs packet data to the transmitter ...

07/21/05 - 20050157802 - Apparatus and method for receiving signals in an ofdm communication system
A receiving apparatus in an OFDM communication system, in which the receiving apparatus includes a serial-to-parallel converter that converts a serial signal received through an antenna to parallel signals. A pre-processor processes an nth symbol converted in the serial-to-parallel converter using an (n−1)th symbol and an (n+1)th symbol. A Fourier ...

07/21/05 - 20050157801 - Pilot transmission and channel estimation for an ofdm system with excess delay spread
Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, the number of pilot subbands is greater than the cyclic prefix length. This “oversampling” may be achieved by using more pilot subbands in each symbol ...

07/14/05 - 20050152468 - Multicarrier communication system and reception device for same
A reception device receives and demodulates, for each subchannel, data transmitted independently via three subchannels, which are a subchannel of interest and the two upper and lower adjacent subchannels which interfere with the subchannel of interest. A reception portion provided for each subchannel computes, as a soft decision value, the ...

07/14/05 - 20050152467 - System and method for canceling radio frequency interferers (rfi's) in xdsl signals
A system and method for canceling noise in a received signal are provided. A signal is received at a receiver comprising a frequency domain equalizer (FEQ). A noise prediction error of the signal is determined. The FEQ is updated with the noise prediction error, wherein the act of updating mitigates ...

07/14/05 - 20050152466 - Multicarrier communication system and methods for link adaptation using uniform bit loading and subcarrier puncturing
A method for selecting transmission parameters of a multicarrier communication channel comprises setting a power level for active subcarriers of a multicarrier communication channel based on a number of the active subcarriers to achieve a highest channel capacity. ...

07/14/05 - 20050152465 - System and method for selecting data rates to provide uniform bit loading of subcarriers of a multicarrier communication channel
A data rate is selected for subcarriers of each frequency and spatial channel of a slowly varying frequency selective multicarrier channel to provide uniform bit loading (UBL) for faster link adaptation. Signal to noise ratios (SNRs) for subcarriers of the multicarrier communication channel may be calculated from channel state information ...

07/14/05 - 20050152464 - Multi-channel wavelet codec
An apparatus and method of for using wavelets filters computed from a wavelet transform as a means of pulse shaping binary data transmitted and received over multiple parallel channels. At the transmitter: (1) the data is parsed from a serial bit stream to several parallel streams; (2) within each of ...

07/14/05 - 20050152463 - I/q mismatch compensation in an ofdm receiver in presence of frequency offset
A receiver for an orthogonal frequency division multiplex radio signal in which a carrier frequency is modulated by sub-carrier signals (S1) coded with data. Analogue signal processing means (3 to 12) produces base-band analogue signals (I-Rx, Q-Rx) in phase quadrature and analogue-to-digital converters (13, 14) convert the analogue signals to ...

07/07/05 - 20050147176 - Ici cancellation method for an ofdm system
In the ICI cancellation method for OFDM communication system, a receiver performs channel estimation using pilot subcarriers included in transmission signals transmitted from at least one transmitter. The transmitter generates the transmission signal in which pilot subcarriers and data subcarriers are regularly arranged, performs preceding on the transmission signal, modulates ...

06/30/05 - 20050141627 - Method to create hierarchical modulation in ofdm
The present invention involves a method for transmitting data using an orthogonal frequency division multiplex (OFDM) transmission system, such as over a terrestrial network used in satellite digital audio radio. A OFDM signal is generated based on first input data. A variation is introduced in the OFDM signal based on ...

06/30/05 - 20050141626 - Uplink channel estimation system for orthogonal frequency division multiple access system and method thereof
In the uplink of an OFDMA system, a preamble is used to estimate a channel and then the pilot tones of a data symbol are used for channel estimation to update the channel estimate. The channel estimate is used for channel compensation, and the phase of the channel is corrected ...

06/30/05 - 20050141625 - Apparatus, method and computer program for detecting echo in the frequency domain
A method, apparatus and computer program for detecting an echo signal including interpolating at least one fast Fourier transformed OFDM signal received in the time-domain, interpolating the at least one signal generated by the time-domain interpolation in the frequency-domain, using a time-domain varying bandwidth low pass filter (LPF), with bandwidth ...

06/30/05 - 20050141624 - Multiantenna communications apparatus, methods, and system
A transmitter may transmit using OFDM-MIMO or OFDM-SDMA depending on channel characteristics. ...

06/23/05 - 20050135496 - Arrangements and methods for per tone equalization with reduced complexity
An equalizer for a multi carrier signal for carrying out equalization adapted to each carrier or group of carriers, Fourier transforms the multi carrier signal, and obtains difference terms of the multi carrier signal. Both are input to an adaptive filter, to output equalized signals, wherein decimation is applied to ...

06/23/05 - 20050135495 - Method and system for enhancing bit rate in dmt quad spectrum systems
A method and system for achieving a maximum bit rate in a DMT system using a quad spectrum under constraints of avoiding interference with radio frequency interference (RFI). The methods of an embodiment of the present invention, when combined in various combinations, optimize bit allocation and utilizes bins in notched ...

06/23/05 - 20050135494 - Forming multi-carrier signals
A method for forming a multi-carrier output signal for transmission in a communication system, the multi-carrier output signal being formed from a plurality of data signals each modulated with a respective one of a plurality of carrier signals, the method comprising: establishing two or more sets of carrier signals, each ...

06/23/05 - 20050135493 - Method and adaptive bit interleaver for wideband systems using adaptive bit loading
An adaptive interleaver for wideband orthogonal frequency division multiplexed (OFDM) communications permutes a variable number of coded bits per OFDM symbol (Ncbps). The variable number of coded bits is calculated based on individual subcarrier modulation assignments for orthogonal subcarriers of a wideband channel. The interleaver matrix size may be based ...

06/23/05 - 20050135492 - Interference-weighted communication signal processing systems and methods
A level of interference affecting signal components of received communication signals is estimated and used to weight the signal components. The signal components in a each of a number of groups of signal components are weighted based on respective interference estimates to thereby adjust signal components for coloured interference, which ...

06/16/05 - 20050129136 - Ofdm receiver
An OFDM receiver receives an OFDM signal transmitted from an OFDM transmitter by using a sub-carrier. The OFDM receiver includes a channel estimator configured to obtain a channel estimated value of each multi-path based on OFDM signals received through a plurality of multi-paths; a transmission signal estimated value calculator configured ...

06/16/05 - 20050129135 - Method and apparatus for compensating for residual frequency offset in an ofdm system
Disclosed is a method for compensating for a residual frequency offset in an orthogonal frequency division multiplexing system comprising the steps of: a) performing a fast fourier transform for an input signal to convert the input signal into a serial signal; b) detecting signal power of the serial signal to ...

06/09/05 - 20050123060 - System and method for channelization recognition in a wideband communication system
The channelization of a WB OFDM channel may be determined by detecting a plurality of subchannels and generate a channelization vector indicating which of the subchannels are active and which of the subchannels are inactive. In response to the channelization vector, data-symbol processing may be performed on the active subchannels ...

06/02/05 - 20050117657 - Channel noise estimating method and apparatus applied to a multi-carrier system
A channel noise estimating method and apparatus applied to a multi-carrier system are disclosed, where data symbols received by a receiving unit are applied to reconstruct the original transmitted data symbols. The reconstructing process is performed by either a soft decision or a hard decision technique to simulate the original ...

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