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Communication system, base station, and mobile stationRelated Patent Categories: Telecommunications, Transmitter And Receiver At Separate Stations, Having Measuring, Testing, Or Monitoring Of System Or Part, Noise, Distortion, Or Unwanted Signal Detection (e.g., Quality Control, Etc.)Communication system, base station, and mobile station description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060148412, Communication system, base station, and mobile station. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] The present invention relates to a communication system, base station, and mobile station of mobile communications for carrying out high-speed radio data communication. BACKGROUND ART [0002] A plurality of communication schemes called a third generation are adopted as IMT-2000 by ITU (International Telecommunication Union) as mobile radio communication schemes typified by mobile telephones. Among them, W-CDMA (Wideband Code Division Multiple Access) was put into commercial service in Japan in 2001. [0003] The W-CDMA scheme aims to achieve a communication rate of about 2 Mbps (megabits per second) per mobile station at the maximum. The first specification was decided and published by 3GPP (Third-Generation Partnership Project; http://www.3gpp.org), one of the standardization groups, as Release 1999, a version standardized in 1999. Incidentally, as a detailed manual of the W-CDMA FDD schemes in general, "W-CDMA mobile communication system", supervised by Keiji Tachikawa, Maruzen Co., Ltd. is known. [0004] FIG. 1 is a schematic diagram showing a conventional communication system based on the W-CDMA scheme. In FIG. 1, the reference numeral 1 designates a base station (BS), 2 designates a mobile station (MS) that carries out radio communication with the base station 1, 3 designates a downlink, 3a designates a channel (dedicated channel) assigned to the mobile station individually among the downlink 3 used by the base station 1 for transmitting data to the mobile station 2, 3b designates a channel (shared channel) transmitted to a plurality of mobile stations in common among the downlink 3, and 4 designates an uplink (dedicated channel) used by the mobile station 2 for transmitting data to the base station 1. [0005] The W-CDMA is divided into FDD (Frequency Division Duplex) that assigns different radio frequencies to downlink 3 and uplink 4, and TDD (Time Division Duplex) that utilizes the same radio frequency and separates the downlink 3 and uplink 4 on a time division basis. Here, the FDD will be described. [0006] Next, the operation will be described. [0007] The downlink 3a consists of a DPDCH (Dedicated Physical Data CHannel), a data channel, and a DPCCH (Dedicated Physical Control CHannel), a control channel. Both the channels are time division multiplexed and transmitted. [0008] The downlink 3b is a CPICH (Common Pilot CHannel) for transmitting a pilot signal for the mobile station 2 to establish synchronization with the base station 1. [0009] The downlink 3a and downlink 3b are multiplied by spreading codes different for individual transmission data to separate the channels, followed by multiplication of a base station identification code (the so-called scramble code) assigned to the base station 1 to be transmitted. [0010] The uplink 4 consists of a DPDCH (Dedicated Physical Data CHannel), a data channel, and a DPCCH (Dedicated Physical Control CHannel), a control channel, which are transmitted after undergoing IQ multiplexing. [0011] The uplink 4 is multiplied by spreading codes different for individual transmission data to separate the channels, followed by the IQ multiplexing, and by multiplication by a mobile station identification code (the so-called scramble code) assigned to the mobile station 2 to be transmitted. [0012] Recently, a large volume packet data transmission method has become popular in which a transmission rate of the downlink 3 is higher than that of the uplink 4, which is typified by the utilization of the Internet. To further increase the rate of the downlink data to be transmitted from the base station 1 to the mobile station 2 in this method, HSDPA (High Speed Downlink Packet Access), in which exclusive downlink for high-speed packet transmission is to be added, has been proposed and studied (see "High Speed Downlink Packet Access: Physical Layer Aspects (Release 5)" of 3GPP specification TR25.858 v1.1.2 (2002-02)) FIG. 2 is a diagram showing a configuration of the HSDPA. In FIG. 2, the reference numeral 5 designates an exclusive downlink for the high-speed packet transmission, and 6 designates an uplink. The remaining components are the same as those of FIG. 1. [0013] Next, the operation will be described. [0014] The downlink 5, which is transmitted using a so-called shared channel common to a plurality of mobile stations, is divided into a HS-DSCH (High Speed-Downlink Shared CHannel), a data channel, and a HS-SCCH (High Speed-Shared Control CHannel), a control channel. [0015] It has been decided that the HS-DSCH employs AMC (Adaptive Modulation and Coding) that can adaptively vary a modulation scheme (such as QPSK and 16 QAM) and an error-correcting coding rate in accordance with a downlink environment (quality). In addition, because of packet transmission, retransmission control (ARQ: Auto Repeat reQuest) is carried out for reception error. [0016] Furthermore, both the channels (HS-DSCH and HS-SCCH) are subjected to channel separation and base station identification just as the other downlinks (downlinks 3a and 3b). [0017] In addition, to add the new downlink 5, it has been studied that the mobile station 2 transmits, to the base station 1, response data (ACK/NACK) corresponding to the downlink high-speed packet data, and downlink quality information (QI: Quality Indicator). To transmit the response data, a dedicated individual control channel (uplink 6) is added as shown in FIG. 2. [0018] As for the uplink 6, it has been studied to separate and identify the channel using a spreading code for channel separation in the same manner as the conventional uplink channel, followed by carrying out additional IQ multiplexing to the conventional uplink 4. In TR25.858, the dedicated control channel is referred to as "HS-DPCCH" (High Speed-Dedicated Physical Control CHannel). [0019] As for the ACK/NACK, it has been studied to transmit from the mobile station 2 only when data is transmitted from the base station 1 through the downlink 5, and is not transmitted unless a packet is transmitted. As for the QI, it is studied to transmit it from the mobile station 2 to the base station 1 periodically. Accordingly, the transmissions are performed independently. [0020] The transmission cycle and timing offset of the QI is specified by the base station 1 as parameters in advance, and their values (report cycle k, and offset) are defined in TR25.858. The values and ranges of these values, however, are provisional values for discussion, and have not yet been determined. The provisional values of the k are 0, 1, 5, 10, 20, 40, 80, and 160, and the ranges of the offset for each k can take values of 0.ltoreq.offset.ltoreq.k-1. Since the k and offset are parameters, they can be altered halfway through the communication in accordance with a variable rate of the downlink environment. [0021] FIG. 3 is a diagram illustrating a format of the HS-DPCCH, which will be described below. [0022] It has been studied to separate the ACK/NACK data field from the QI data field in time, and to assign the QI twice the time assigned to the ACK/NACK. The combination of the two data is specified in terms of a time unit (Subframe) of 2 ms. The Subframe is also a transmission unit of the HSDPA downlink 5. Continue reading about Communication system, base station, and mobile station... Full patent description for Communication system, base station, and mobile station Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Communication system, base station, and mobile station patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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