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Lei Xu patents

Recent bibliographic sampling of Lei Xu patents listed/published in the public domain by the USPTO (USPTO Patent Application #,Title):



11/20/14 - 20140341568 - High-throughput network traffic monitoring through optical circuit switching and broadcast-and-select communications
A network traffic collecting and monitoring system includes a traffic processing and dispatching module that pre-processes network traffic received from traffic tapping modules. A traffic collecting module receives and consolidates the network traffic and sends the network traffic to higher-layer applications. A controller dynamically configures the traffic processing and dispatching...
Inventors: Yueping Zhang, Lei Xu (Sodero Networks, Inc.)

09/18/14 - 20140270761 - Method and apparatus for efficient and transparent network management and application coordination for software defined optical switched data center networks
Application actions are optimized by receiving actions from one or more distributed applications, translating the received actions into one or more network operation primitives, processing the network operation primitives to determine an optimized set of network operation primitives, determining an optimal execution sequence for the optimized set of network operation...
Inventors: Lei Xu, Yueping Zhang (Sodero Networks, Inc.)

08/14/14 - 20140226975 - Method and apparatus for boosting data intensive processing through optical circuit switching
A method is provided for improving performance of a distributed computing task being executed by computing devices interconnected by an optical switching fabric. Traffic flows between a plurality of nodes of a MapReduce application using an interconnected optical switching fabric are monitored. One or more optimizations for the interconnected optical...
Inventors: Yueping Zhang, Lei Xu (Sodero Networks, Inc.)

07/24/14 - 20140205283 - Multidimensional coded-modulation for high-speed optical transport over few-mode fibers
Systems and methods for data transport are provided which encode streams of data using low density parity check (LDPC) encoders and map data streams to symbols, by assigning bits of symbols to a signal constellation and associating bits with constellation points. Constellation points are generated using a D-dimensional optimum signal...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

05/01/14 - 20140119728 - Method and apparatus for implementing a multi-dimensional optical circuit switching fabric
An optical switching system is described. The system includes a plurality of interconnected wavelength selective switching units. Each of the wavelength selective switching units is associated with one or more server racks. The interconnected wavelength selective switching units are arranged into a fixed structure high-dimensional interconnect architecture comprising a plurality...
Inventors: Yueping Zhang, Lei Xu (Sodero Networks, Inc.)

08/15/13 - 20130209035 - Optical dispersion compensation module using fiber bragg grating with multiple degrees of freedom for the optical field
Systems and methods are disclosed for enhancing optical communication by performing dispersion compensation in an optical fiber using a fiber Bragg grating (FBG); and providing increased degrees of freedoms (DOFs) to distinguish forward and backward propagating fields with a passive component....
Inventors: Fatih Yaman, Eduardo Mateo, Lei Xu, Shaoliang Zhang, Ting Wang (Nec Laboratories America, Inc.)

05/02/13 - 20130108270 - Variable bit-rate qpsk transmitter and method employing polarization manipulation
Disclosed are universal QPSK transmitter structures and methods for generating different QPSK signals exhibiting different polarization schemes, namely PolMux, PolMod and PolSw. The bit rate of the generated signals is variable, thereby allowing the transmitter to adjust to varying network traffic conditions. Advantageously, the generated signals may be detected by...
Inventors: Shaoliang Zhang, Dayou Qian, Junqiang Hu, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

04/18/13 - 20130094851 - Optical spectral shaping for nonlinearity enhancement in high speed digital coherent optical transmissions
A method includes evaluating an optical signal spectrum for estimated filtering parameters of an optical spectral filtering device for shaping optical signal spectrum, determining a feedback for fine tuning the optical spectral filtering device for nonlinearity tolerance enhancement in the optical transmission system, responsive to received optical signal quality in...
Inventors: Lei Xu, Shaoliang Zhang, Fatih Yaman, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki (Nec Laboratories America, Inc.)

04/11/13 - 20130091399 - High-speed long codeword qc-ldpc soft decision decoder
A Quasi-Cyclic, LDPC, large girth, soft-decision decoder and accompanying methods....
Inventors: Junqiang Hu, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

04/11/13 - 20130091398 - Optimum signal constellation design for high-speed optical transmission
Systems and methods for data transport, comprising encoding one or more streams of input data with one or more low density parity check (LDPC) encoders, corresponding to one or more polarization/spatial mode branches. One or more encoded data streams are mapped to symbols, wherein the mapper is configured to assign...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

04/11/13 - 20130089327 - Polarization switching for optical fiber communications
A method implemented in a transmission apparatus used in an optical fiber communications system for a polarization switched differential quaternary phase-shift keying (DQPSK) signal is disclosed. The method comprises splitting data into two or more data streams, inputting said two or more data streams to 1-bit DQPSK precoders to perform...
Inventors: Shaoliang Zhang, Lei Xu, Junqiang Hu, Fatih Yaman, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki (Nec Laboratories America, Inc.)

04/11/13 - 20130089326 - Nonbinary ldpc coded modulation without bandwidth expansion for high-speed optical transmission
Systems and methods for data transport, comprising encoding one or more streams of input data using nonbinary low density parity check (NB-LDPC) encoders, corresponding to orthogonal polarization states. Receiving one or more streams of input data using a buffer coupled to the encoders, the data written to the buffer bR...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

12/20/12 - 20120321318 - Carrier and subcarrier hopping for optical ofdm security
Methods and systems for secure communication include assigning data streams to respective orthogonal sub-carriers according to random number information at a transmitter. The data streams are modulated onto the respective orthogonal sub-carriers before the orthogonal sub-carriers are transmitted. The random number information is transmitted on a second medium, separate from...
Inventors: Lei Xu, Dayou Qian, Ting Wang (Nec Laboratories America, Inc.)

12/20/12 - 20120321311 - Coherent interleaved polarization-multiplexing optical communications with single iq modulator
An inventive method for coherent interleaved polarization-multiplexing PolMux optical communications with a single IQ modulator includes modulating a light source to generate a 50% return-to-zero RZ signal pulse at a frequency Rs, driving a single IQ modulator with inphase I and quadrature phase Q data at a bit rate of...
Inventors: Shaoliang Zhang, Fatih Yaman, Lei Xu, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki (Nec Laboratories America, Inc.)

12/20/12 - 20120321303 - Multiple-symbol polarization switching for differential-detection modulation formats
An inventive method for multi-symbol polarization switching for differential detection optical systems includes modulating a laser source by a DQPSK modulator, driving the DQPSK modulator with a data block configured for generating multi-symbol polarization-switched DQPSK differential-encoded signals, and polarizing the multi-symbol polarization-switched DQPSK signals with a polarizing modulator whose modulation...
Inventors: Shaoliang Zhang, Fatih Yaman, Lei Xu, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki (Nec Laboratories America, Inc.)

12/06/12 - 20120307933 - Energy efficient constellation method and system
A method and apparatus employing statistical physics energy minimization methods to signal constellation design. By using statistical physics concepts, an energy-efficient signal constellation design algorithm (EE-SCDA) is described. In the presence of amplified spontaneous emission (ASE) noise and channel impairments, we use EE-SCDA to determine a source distribution, and represent...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/18/12 - 20120263468 - Generation of optical quadrature duobinary format using optical delay
An optical method for generating an optical quadrature duobinary QDB signal includes receiving a quadrature phase-shift-keying QPSK signal, and adding a delay to the received quadrature phase-shift-keying QPSK signal to generate an optical quadrature duobinary signal....
Inventors: Fatih Yaman, Shaoliang Zhang, Lei Xu, Yin Shao, Ting Wang (Nec Laboratories America, Inc.)

10/18/12 - 20120263466 - Multidimensional hybrid modulations for ultra-high-speed optical transport
Systems and methods are disclosed with a spatial-domain-based multi-dimensional coded-modulation scheme that improves dramatically OSNR sensitivity and tolerance to fiber nonlinearities by using D-dimensional signal constellations, where D=2(2+M)N. The factor 2 originates from two polarizations, 2+M electrical basis functions are selected (2 in-phase/quadrature channels and M pulse-position like basis functions),...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/18/12 - 20120263251 - Generalized ofdm (gofdm) for ultra-high-speed serial optical transport networks
A coded multidimensional modulation system called generalized OFDM (GOFDM) uses orthogonal subcarriers as bases functions, and the signal constellation points of corresponding multidimensional constellation diagram are obtained as N-dimensional Cartesian product of one-dimensional PAM/two-dimensional QAM. In GOFDM, the N-dimensional/2N-dimensional signal constellation point is transmitted over all N subcarriers/2N-subcarriers, which serve...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/11/12 - 20120260142 - Four-dimensional non-binary ldpc-coded modulation schemes for ultra high-speed optical fiber communication
Systems and methods are disclosed for communicating signals, by receiving a K-symbol-long input block from a 2m-ary source channel; encoding the input block into a 2m-ary non-binary low-density parity-check (LDPC) codeword of length N; and mapping each 2m-ary symbol to a point in a signal constellation comprised of 2m points,...
Inventors: Murat Arabaci, Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/11/12 - 20120257896 - Coded multidimensional pulse amplitude modulation for ultra-high-speed optical transport
Systems and methods are disclosed to provide optical communication by using subcarriers as individual bases functions, obtaining signal constellation points of an N-dimensional pulse amplitude modulation (ND-PAM) constellation diagram as an N-dimensional Cartesian product of a one-dimensional PAM; and transmitting the N-dimensional signal constellation point over all N orthogonal subcarriers...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/11/12 - 20120257895 - Four-dimensional optical multiband-ofdm for beyond 1.4tb/s serial optical transmission
Systems and methods are disclosed to perform four-dimensional optical multiband OFDM communication by organizing an N-dimensional (ND) signal constellation points as a signal matrix; performing 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and applying both orthogonal polarizations in the OFDM communication to deal with chromatic dispersion, PMD...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/04/12 - 20120251111 - Optoelectronic wavelength converter for polarization multiplexed optical signals
A wavelength converter that operates on an optical signal having single or multiplexed polarizations and which exhibits any modulation format....
Inventors: Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

10/04/12 - 20120251028 - Polarization-alternating optical signal generation using csrz modulation
A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a π phase difference between adjacent symbols of the data modulated optical signal...
Inventors: Fatih Yaman, Shaoliang Zhang, Lei Xu, Ting Wang, Yoshihisa Inada, Takaaki Ogata, Yasuhiro Aoki (Nec Laboratories America, Inc.)

08/23/12 - 20120216093 - Soft-decision non-binary ldpc coding for ultra-long-haul optical transoceanic transmissions
Methods and systems for soft-decision non-binary low-density parity-check (LDPC) coding for ultra-long-haul optical transoceanic transmissions are provided. A receiver includes one or more maximum a posteriori (MAP) equalizers configured to decode one or more symbols of an encoded input stream to provide one or more symbol log-likelihood ratios (LLRs). One...
Inventors: Ivan B. Djordjevic, Shaoliang Zhang, Lei Xu, Fatih Yaman, Ting Wang (Nec Laboratories America, Inc.)

08/16/12 - 20120207470 - Spatial domain based multi dimensional coded modulation for multi tb per second serial optical transport networks
An optical transport network based on multimode/multicore fibers includes a mode-multiplexer to multiplex independent data streams from one or more transmitters; a multimode erbium-doped fiber amplifier (MM EDFA) to compensate for MMF loss; a multimode optical add-drop multiplexer (MM OADM) to add and/or drop multimode channels in multimode networks; a...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

05/03/12 - 20120106983 - Optimized normalized least mean square phase estimation
Methods and systems for normalized least mean square phase estimation are shown that include receiving optical transmissions that include a modulated signal, determining a step size based on a signal-to-noise ratio (SNR) and a laser linewidth that provides a balance between convergence speed and precision, estimating phase error using the...
Inventors: Lei Xu, Shaoling Zhang, Ting Wang (Nec Laboratories America, Inc.)

04/26/12 - 20120099863 - Hybrid optical/electrical switching system for data center networks
In one aspect, a system includes one or more electrical switches to transfer data in a data network; one or more optical switching groups coupled to each electrical switch, each switching group having one or more server racks, each server rack coupled to a top of rack (TOR) switch and...
Inventors: Lei Xu, Yueping Zhang, Atul Singh, Guofei Jiang, Ting Wang (Nec Laboratories America, Inc.)

04/05/12 - 20120084617 - Modified progressive edge-growth ldpc codes for ultra-high-speed serial optical transport
Systems and methods enabling ultra-high-speed optical transport The systems and methods include receiving a modulated, encoded input stream. Channel impairments are removed using MAP equalization. Symbols are detected in the input stream to produce a stream of encoded data. The stream of encoded data is decoded with one or more...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

03/01/12 - 20120051452 - Modified coded hybrid subcarrier amplitude phase polarization modulation
Methods and systems for optical communication using hybrid subcarrier/amplitude/phase/polarization modulation are shown that include LDPC encoding a plurality of groups of bitstreams. The groups of bitstreams are mapped to the points of a three-dimensional constellation that is represented by the vertices of a regular polyhedron and its dual. Each group...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

02/23/12 - 20120047415 - Reverse concatenated encoding and decoding
Methods and systems for transmitting and receiving data include reverse concatenated encoding and decoding. Reverse concatenated decoding includes inner decoding the encoded stream with an inner decoder that uses a low-complexity linear-block code to produce an inner-decoder output stream, outer decoding the inner-decoder output stream with an outer decoder that...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

01/12/12 - 20120008945 - Optical switching network
Systems and methods are disclosed to communicate over an optical network by using hop-by-hop routing over an optical network; and dynamically constructing a network topology....
Inventors: Ankit Singla, Atul Singh, Kishore Ramachandran, Lei Xu, Yueping Zhang (Nec Laboratories America, Inc.)

01/12/12 - 20120008944 - Optical switching network
Systems and methods are disclosed for a method to communicate over an optical network by using hop-by-hop routing over an optical network; and dynamically constructing a network topology....
Inventors: Ankit Singla, Atul Singh, Kishore Ramachandran, Lei Xu, Yueping Zhang (Nec Laboratories America, Inc.)

01/12/12 - 20120008943 - Optical switching network
Systems and methods are disclosed for a method to communicate over an optical network by using hop-by-hop routing over an optical network; and dynamically constructing a network topology....
Inventors: Ankit Singla, Atul Singh, Kishore Ramachandran, Lei Xu, Yueping Zhang (Nec Laboratories America, Inc.)

12/22/11 - 20110314352 - Reduced-complexity ldpc decoding
Methods and systems for reduced-complexity decoding of low-density parity-check (LDPC) information. An encoded input stream is received. The received stream is decoded with one or more reduced-complexity min-sum or a posteriori probability LDPC decoders. A v-node update rule in the reduced complexity decoder is omitted....
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

08/11/11 - 20110194855 - Superimposed training and digital filtering coherent optical receivers
In a polarization-multiplexing optical communications system, a method and system for coherent reception of polarization-multiplexed optical communications. Training and data sequences are recovered from a plurality of orthogonally polarized signals, such that training and data sequences may be used on a single channel without loss of spectral efficiency. This is...
Inventors: Hussam G. Batshon, Lei Xu, Ting Wang, Ivan B. Djordjevic (Nec Laboratories America, Inc.)

07/28/11 - 20110182428 - Secure communication over passive optical network (pon) with quantum encryption
Systems and methods to communicate securely includes communicating quantum encryption data on a first wavelength-division multiplexing passive optical network (WDM-PON); and communicating data over separate classical channels of a second WDM-PON, wherein the second WDM-PON synchronizes with the first WDM-PON while providing data communication over the classical channels....
Inventors: Yi Zhao, Martin Roetteler, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

04/14/11 - 20110085797 - Ultra wide-range frequency offset estimation for digital coherent optical receivers
Methods and systems for receiving an optical signal using cascaded frequency offset estimation. Coherently detecting an optical signal includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal, compensating for a residual...
Inventors: Lei Xu, Shaoliang Zhang, Jianjun Yu, Ting Wang (Nec Laboratories America, Inc.)

04/14/11 - 20110085624 - Coded polarization-multiplexed iterative polar modulation
Systems and methods for optical communication that use a transmitter/receiver. The systems and methods include receiving a modulated, encoded input stream. Channel memory is reduced using coarse digital backpropagation and other channel impairments are removed using turbo equalization. Symbols are detected in the input stream that conform to a non-uniform,...
Inventors: Ivan B. Djordjevic, Lei Xu, Ting Wang (Nec Laboratories America, Inc.)

09/30/10 - 20100247104 - Optical communication system and method for generating dark return-to-zero and dwdm optical mm-wave generation for rof downstream link using optical phase modulator and optical interleaver
A method of generating a dark-RZ pulse in an optical communications system with a dual-arm modulator by setting a direct current bias on the modulator to a specific value such that an output optical power from the modulator achieves a maximum value when the RF signals on the first and...


09/16/10 - 20100232804 - Methods and systems for polarization multiplexed multilevel modulation for optical communication
Multilevel soft-equalizer detectors, such as a maximum a posteriori probability (MAP) detector, suitable for use in polarization multiplexed optical communications using multilevel modulations and coherent detection are disclosed. Detection systems and methods may consider two symbols transmitted over two orthogonal polarization states as a two-component symbol, which is effective in...


09/16/10 - 20100232803 - Integrated equalizer and michelson interferometer structure for inter-symbol interference-suppressed colorless dpsk demodulation
An optical device includes an interferometer for a received optical differential phase shift keying DPSK signal, and an equalizer integrated with the interferometer in a manner for reducing from optical filtering effects an interference by signal bits of the DPSK signal with signal bits of a contiguous DPSK signal. The...


09/16/10 - 20100232789 - Modified michelson interferometer structure for inter-symbol interference-suppressed colorless dpsk demodulation
An optical device includes an interferometer for a received optical differential phase shift keying DPSK signal, and an equalizer integrated with the interferometer in a manner for reducing from optical filtering effects an interference by signal bits of the DPSK signal with signal bits of a contiguous DPSK signal. The...


08/26/10 - 20100215371 - Polarization mode dispersion (pmd) compensation in polarization multiplexed coded orthogonal frequency division multiplexing (ofdm) systems
A receiver and method are provided. The receiver includes a detector configured to receive polarization multiplexed coded orthogonal frequency division multiplexing input sequences and generate estimates of unknown transmitted symbols in the input sequences for x- and y-polarization channels with respect to laser phase noise and PMD. A demapper coupled...


08/19/10 - 20100211849 - Multi-dimensional ldpc coded modulation for high-speed optical transmission systems
Arbitrarily high data transmission rates may be achieved by the use of N-dimensional, LDPC-coded modulation. N orthonormal basis functions are employed using coherent reception, resulting in a proportional increase in transmission rate with only a modest increase in bit-error ratio....


04/08/10 - 20100088571 - High speed ldpc decoding
An optical probability-domain LDPC decoder suitable for implementation at 100 Gb/s and above provides large coding gains when based on large-girth LDPC codes. A basic building block, the probabilities multiplier circuit, used to implement both check node and probability node update circuits can be implemented using Mach-Zehnder delay interferometer....


04/08/10 - 20100086314 - Method and apparatus for an optical duty cycle for an optical digital coherent system
An optical apparatus includes a quadrature phase shift keying modulator for generating a non-return-to-zero quadrature phase shift keyed NRZ-QPSK signal from a received lightwave, the modulator being driven by a radio frequency RF signal, an intensity modulator for carving the NRZ-QPSK signal to return-to-zero RZ pulses with a different duty...


02/25/10 - 20100050048 - Mitigation of fiber nonlinearities in multilevel coded-modulation schemes
A receiver and method are provided for mitigation of finer non-linearities in multilevel coded-modulation schemes. The receiver includes a multilevel Bahl-Cocke-Jelinek-Raviv (BCJR) equalizer configured to receive channel samples of an input signal, partially mitigate fiber non-linearities, and provide symbol reliabilities. The receiver further includes a bit probabilities module coupled to...


02/04/10 - 20100027994 - Phase modulation of an optical orthogonal frequency division multiplexing signal
A method includes generating an optical orthogonal frequency division multiplexing OFDM signal with in-phase and quadrature-phase components; varying an RF carrier according to the in-phase and quadrature-phase components; and modulating a phase of a lightwave carrier according to the varied RF carrier to generate an optical OFDM signal with equalized...


12/03/09 - 20090297144 - Polarization mode dispersion compensation in multilevel coded-modulation schemes using blast algorithm and iterative polarization cancellation
Receivers and methods are provided for polarization mode dispersion compensation in multi-level coded-modulation schemes using a BLAST algorithm and iterative polarization cancellation. A receiver includes a vertical Bell Laboratories Layered Space-Time Architecture (V-BLAST) orthogonal frequency division multiplexing (OFDM) detector configured to receive input sequences and partially cancel polarization interference with...


11/19/09 - 20090285577 - Optical frontend for integration of optical and wireless networks
Data is transmitted by radio over fiber in a wavelength division multiplex optical transmission system. Data is transmitted over a single optical channel by directly modulating a single wavelength laser with a baseband data signal. Multiple single wavelength laser beams are multiplexed into a single multi-wavelength laser beam. All of...


11/12/09 - 20090282314 - Multidimensional turbo product codes and generalized low-density parity-check codes with component reed-solomon codes for optical transmission
A transmitter, a receiver, and corresponding methods are provided. The transmitter includes encoders configured to encode source bit streams from L information sources into bytes of codewords. Each encoder includes different (n, k) multidimensional turbo-product codes of code rate R=k/n, where k is a number of information bytes, and n...


11/05/09 - 20090274460 - Differential delay receiver using cross-polarization interferometer for polmux-dpsk system
A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, and a...


10/15/09 - 20090259912 - Ldpc codes and stochastic decoding for optical transmission
A method for error correction and a decoder using low density parity check (LDPC) codes includes initializing extrinsic probability information between variable nodes and check nodes in a bipartite graph including generating a Bernoulli sequence according to a probability of a bit having a value one. Parity checking is performed...


10/01/09 - 20090245810 - Dynamic signal equalization in optical transmission systems
In an optical transmission system, data is transmitted via an optical beam modulated with an arbitrary waveform. The optical beam is transmitted through at least one optical element. Transmission through at least one optical element degrades the signal quality of the initial optical beam. The signal characteristics of at least...


09/17/09 - 20090235143 - Ldpc-coded multilevel modulation scheme
A PMD compensation scheme suitable for use in multilevel block-coded modulation schemes with coherent detection....


09/10/09 - 20090228766 - Simulatenous pmd compensation and chromatic dispersion compensation using ldpc coded ofdm
A method includes estimating quadrature amplitude modulated QAM symbols in an LDPC encoded OFDM signal for transmission, performing channel estimation by training sequence to determine channel coefficients in reception of the LDPC encoded OFDM signal; and obtaining channel information detection and decoding of the LDPC encoded signal....


08/13/09 - 20090202243 - Direct detection for receiving polarization multiplexing signals
There is provided a method for detecting optical signals comprising employing a photo diode to both directly detect a received optical signal and convert it into an electrical signal for recovery of data bit stream information in the received optical signal, the received optical signal being derived from a separation...


08/06/09 - 20090199065 - Gldpc encoding with reed-muller component codes for optical communications
A method of encoding for optical transmission of information includes encoding information with a generalized low-density parity-check (GLDPC) code for providing coding gains, and constructing the GLDPC code with a Reed-Muller RM code as a component code, the component code being decodable using a maximum posterior probability (MAP) decoding. In...


07/09/09 - 20090177945 - Polarization mode dispersion compensation using bcjr equalizer and iterative ldpc decoding
A turbo equalizer includes a Bahl-Cocke-Jelinek-Raviv (BCJR) equalizer configured to receive a transmitted signal and partially cancel inter-symbol interference (ISI) due to polarization-mode dispersion (PMD). A low-density parity check (LDPC) decoder is coupled to the BCJR equalizer to receive channel bit reliabilities therefrom. The LDPC decoder iteratively provides extrinsic soft...


06/25/09 - 20090162066 - Intra-channel equalizing optical interleaver
An apparatus includes an interleaver configuration for at least one of combining or separating odd and even channel groups to achieve channel density doubling; and an optical equalizer for suppressing inter symbol interference within the channels to provide intra-channel equalizing in the optical path, the equalizer being integrated into the...


04/09/09 - 20090092393 - Coherent optical orthogonal frequency division multiplexing (ofdm) reception using self optical carrier extraction
A method includes producing interference between a received optical OFDM signal and an optical carrier extracted from the received optical OFDM signal to provide optical coherent detection of the received optical OFDM signal. Preferably, producing the interference includes optically splitting the received optical OFDM signal into a first part that...


03/05/09 - 20090059351 - Demodulator system and method using multilevel differential phase shift keying
A demodulator and demodulation method includes an optical coupler configured to receive an input signal. The optical coupler couples the signal to an even number of branches. Each branch including at least one interferometer configured to split, combine and interfere with an optical signal from one of within the branch...


02/26/09 - 20090052907 - Wavelength transmission system and method using 3-dimensional ldpc-coded modulation
A transmitter and method include a LDPC encoder configured to encode source data, and a mapper configured to generate three coordinates in accordance with a 3D signal constellation where the coordinates include an amplitude coordinate and two phase coordinates. A laser source is modulated in accordance with each of the...


Sodero Networks, Inc., Nec Laboratories America, Inc., Nec Laboratories America, Inc, Nec Laboratories America Inc, Nec Laboratories America

Archived*
(*May have duplicates - we are upgrading our archive.)

20120321318 - Carrier and subcarrier hopping for optical ofdm security


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The bibliographic references displayed about Lei Xu's patents are for a recent sample of Lei Xu's publicly published patent applications. The inventor/author may have additional bibliographic citations listed at the USPTO.gov. FreshPatents.com is not associated or affiliated in any way with the author/inventor or the United States Patent/Trademark Office but is providing this non-comprehensive sample listing for educational and research purposes using public bibliographic data published and disseminated from the United States Patent/Trademark Office public datafeed. This information is also available for free on the USPTO.gov website. If Lei Xu filed recent patent applications under another name, spelling or location then those applications could be listed on an alternate page. If no bibliographic references are listed here, it is possible there are no recent filings or there is a technical issue with the listing--in that case, we recommend doing a search on the USPTO.gov website.

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