WO2013093973A1 - Wireless communication system, wireless communication method, and wireless communication device - Google Patents

Wireless communication system, wireless communication method, and wireless communication device Download PDF

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Publication number
WO2013093973A1
WO2013093973A1 PCT/JP2011/007186 JP2011007186W WO2013093973A1 WO 2013093973 A1 WO2013093973 A1 WO 2013093973A1 JP 2011007186 W JP2011007186 W JP 2011007186W WO 2013093973 A1 WO2013093973 A1 WO 2013093973A1
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WIPO (PCT)
Prior art keywords
wireless communication
communication device
communication devices
information
transmission
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PCT/JP2011/007186
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French (fr)
Japanese (ja)
Inventor
伊藤　章
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富士通株式会社
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Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to JP2013549956A priority Critical patent/JP5999099B2/en
Priority to PCT/JP2011/007186 priority patent/WO2013093973A1/en
Publication of WO2013093973A1 publication Critical patent/WO2013093973A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/24—Cell structures
    • H04W16/28—Cell structures using beam steering

Definitions

  • the present invention relates to a wireless communication system, a wireless communication method, and a wireless communication apparatus.
  • next-generation wireless communication technologies have been discussed in order to further increase the speed and capacity of wireless communication in wireless communication systems such as mobile phone systems.
  • 3GPP 3rd Generation Partnership Project
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • coordinated multipoint (hereinafter also referred to as CoMP) communication is being studied in order to reduce inter-cell interference and improve received signal strength.
  • CoMP coordinated multipoint
  • a plurality of geographically distant points cooperate to perform communication.
  • Each point corresponds to, for example, a base station, an antenna, or a cell formed by these.
  • dynamic adjustment of transmission or reception between multiple points is performed.
  • uplink multipoint cooperative communication a method of combining signals while receiving signals received in a plurality of cells is being studied.
  • the disclosed technology has been made in view of the above, and an object thereof is to provide a wireless communication system, a wireless communication apparatus, and a wireless communication method capable of improving reception characteristics in multipoint cooperative communication. .
  • a wireless communication system disclosed in the present application is a plurality of first wireless communication devices that transmit data transmitted from a second wireless communication device. Receive. A first transmission unit that transmits information related to transmission timing based on information about the plurality of first wireless communication devices to the second wireless communication device, and the plurality of first wireless communication devices from the second wireless communication device. A second transmission unit that transmits the data at the transmission timing.
  • FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment.
  • FIG. 2 is a sequence diagram for explaining the operation of the wireless communication system.
  • FIG. 3 is a diagram for explaining the reception timing in the wireless communication apparatus.
  • FIG. 4 is a diagram for explaining reception characteristics in the wireless communication device.
  • FIG. 5 is a diagram illustrating a configuration of a wireless communication system according to the second embodiment.
  • FIG. 6 is a diagram illustrating a functional configuration of the base station.
  • FIG. 7 is a diagram illustrating a functional configuration of the mobile station.
  • FIG. 8 is a diagram illustrating a hardware configuration of the base station.
  • FIG. 9 is a diagram illustrating a hardware configuration of the mobile station.
  • FIG. 10 is a sequence diagram for explaining the operation of the wireless communication system.
  • FIG. 11 is a sequence diagram for explaining the operation of the wireless communication system.
  • FIG. 12 is a diagram for explaining the reception timing at the base station.
  • FIG. 13 is a diagram for explaining reception characteristics at the base station.
  • FIG. 14 is a diagram illustrating a configuration of a wireless communication system according to the third embodiment.
  • FIG. 15 is a diagram illustrating a functional configuration of RRH (Remote Radio Head).
  • FIG. 16 is a diagram illustrating a configuration of a wireless communication system according to the fourth embodiment.
  • FIG. 1 shows a configuration of a wireless communication system 1 according to the first embodiment.
  • the wireless communication system 1 includes a plurality of wireless communication devices 10 and 20 and a wireless communication device 30.
  • the wireless communication system 1 can be realized by using the wireless communication devices 10 and 20 as a base station and the wireless communication device 30 as a mobile station.
  • the wireless communication devices 10 and 20 form cells C1 and C2, respectively, and the wireless communication device 30 is located in the cell C1.
  • the wireless communication devices 10 and 20 perform communication between the wireless communication devices 10 and 20 via wired connection or wireless connection, and perform CoMP communication with the wireless communication device 30.
  • the radio communication devices 10 and 20 perform uplink CoMP communication, receive data transmitted by the radio communication device 30 by the radio communication devices 10 and 20, and synthesize a reception signal between the radio communication devices 10 and 20. Process. In this way, by combining received signals between the radio communication devices 10 and 20, inter-cell interference is reduced and received signal strength is improved to improve reception characteristics.
  • the wireless communication apparatus 10 includes an antenna 11, a transmission unit 12, a reception unit 13, and a control unit 14 as functional configurations. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • Each component 21 to 24 of the wireless communication device 20 is the same as each component 11 to 14 of the wireless communication device 10.
  • the control unit 14 acquires information and signals from the wireless communication device 20 via a wired connection or a wireless connection.
  • the control unit 14 determines information related to transmission timing that is a reference when data is transmitted from the wireless communication device 30 based on the information related to the wireless communication devices 10 and 20.
  • the information related to the wireless communication devices 10 and 20 includes, for example, information related to reception quality at the wireless communication devices 10 and 20 measured by the wireless communication devices 10 and 20, and distribution of reception timings at the wireless communication devices 10 and 20. Contains information about.
  • the control unit 14 combines the signal received by the wireless communication device 10 and the signal received by the wireless communication device 20 to execute a decoding process or the like, and acquires data transmitted from the wireless communication device 30.
  • the control unit 14 determines a transmission timing serving as an uplink reference so that information regarding the wireless communication apparatuses 10 and 20 satisfies a predetermined condition.
  • control unit 14 determines a transmission timing serving as an uplink reference so that the reception quality of the combined signal is the highest.
  • the control unit 14 corresponds to an example of a determination unit and a processing unit in this case.
  • the information related to the wireless communication devices 10 and 20 may include various information related to the wireless communication devices 10 and 20 such as the type, installation position, arrangement relationship, or operation status of each wireless communication device 10 and 20.
  • the transmission unit 12 transmits information related to transmission timing serving as an uplink reference to the wireless communication device 30 via the antenna 11.
  • the receiving unit 13 receives data transmitted from the wireless communication device 30 at a reference transmission timing via the antenna 11.
  • the antenna 11 may be separated for transmission and reception.
  • the wireless communication device 10 includes, for example, a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), a memory, and an RF (Radio Frequency) circuit including an antenna as hardware components.
  • the memory includes RAM, such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data.
  • the transmission unit 12 and the reception unit 13 are realized by, for example, an RF circuit.
  • the control unit 14 is realized by an integrated circuit such as a DSP or FPGA.
  • the hardware configuration of the wireless communication device 20 is the same as that of the wireless communication device 10.
  • the wireless communication device 30 includes an antenna 31, a transmission unit 32, a reception unit 33, and a control unit 34 as functional configurations. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the receiving unit 33 receives information related to the reference transmission timing from the wireless communication device 10.
  • the control unit 34 performs processing such as encoding of data to be transmitted.
  • the transmission unit 32 transmits data to the wireless communication devices 10 and 20 at a reference transmission timing.
  • the antenna 31 may be separated for transmission and reception.
  • the wireless communication device 30 includes, as hardware components, for example, a CPU (Central Processing Unit), a memory, and an RF circuit including an antenna.
  • the memory includes RAM such as SDRAM, ROM, and flash memory, for example, and stores programs, control information, and data.
  • the transmission unit 32 and the reception unit 33 are realized by, for example, an RF circuit.
  • the control unit 34 is realized by an integrated circuit such as a CPU, for example.
  • FIG. 2 is a sequence diagram for explaining an operation related to timing control of the wireless communication system 1.
  • the wireless communication devices 10 and 20 each perform reception processing at the control timing of its own device, and the timing synchronization between the reception signal and the reception processing is performed by the uplink from the wireless communication device 30. It has been established by adjusting the transmission timing. For example, when uplink CoMP communication is not performed, the timing synchronization between the radio communication device 30 and the radio communication device 10 corresponding to the serving cell C1 indicates that the uplink transmission timing from the radio communication device 30 is the same as the radio communication device. It is established by adjusting to match the timing of 10 reception processes. Such adjustment is executed, for example, by transmitting a command for adjusting the uplink transmission timing from the wireless communication device 10 to the wireless communication device 30 and performing the next transmission by the wireless communication device 10 in response to this command. Is done.
  • the wireless communication device 30 When performing uplink CoMP communication, the wireless communication device 30 transmits data to the wireless communication devices 10 and 20 using the same channel at the same transmission timing. At this time, depending on the transmission timing serving as an uplink reference, the influence of inter-symbol interference due to the timing difference between the received signal and the reception process may increase, thereby hindering improvement in reception characteristics.
  • the timing difference between the received signal and the received processing is, for example, the position on the time axis of the OFDM (Orthogonal Frequency Division) Multiplexing (OFDM) symbol included in the received signal and the position on the time axis of the FFT (Fast Fourier Transform) window used in the received process. Is the difference. Therefore, in the wireless communication system 1, when performing uplink CoMP communication, timing control is performed as follows.
  • the wireless communication devices 10 and 20 cooperate to acquire information related to the wireless communication devices 10 and 20 (S1).
  • the wireless communication device 10 measures reception quality at the wireless communication device 10.
  • the wireless communication device 10 acquires information such as reception quality measured by the wireless communication device 20 from the wireless communication device 20.
  • the wireless communication devices 10 and 20 cooperate to determine information related to transmission timing that serves as an uplink reference when data is transmitted from the wireless communication device 30 (S2). For example, the wireless communication device 10 uses the information related to the reception quality of the wireless communication devices 10 and 20 to transmit the information related to the transmission timing serving as the uplink reference so that the reception quality of the combined signal satisfies the predetermined condition. decide.
  • standard contains the information which shows the wireless communication apparatus used as the reference
  • the wireless communication device 30 may determine a transmission timing that serves as a reference. Thereby, the transmission timing used as the reference
  • the wireless communication device 10 transmits information related to the reference transmission timing to the wireless communication device 30 (S3).
  • the wireless communication device 10 transmits identification information (cell ID or the like) of a wireless communication device serving as a reference among the wireless communication devices 10 and 20 as information related to a transmission timing serving as a reference.
  • the wireless communication device 30 receives information related to the reference transmission timing, and transmits data to the wireless communication devices 10 and 20 at the reference transmission timing (S4).
  • data is transmitted to the wireless communication devices 10 and 20 at a predetermined transmission timing with respect to the reference wireless communication device.
  • data is transmitted at an appropriate transmission timing adjusted between the wireless communication devices 10 and 20.
  • the data transmitted from the wireless communication device 10 is received by the wireless communication devices 10 and 20, respectively.
  • the wireless communication apparatuses 10 and 20 cooperate to synthesize the signal received by the wireless communication apparatus 10 and the signal received by the wireless communication apparatus 20 to acquire data (S5).
  • the wireless communication device 10 acquires a signal received by the wireless communication device 20 and combines it with the signal received by the wireless communication device 10 to acquire data. Since data is transmitted at the transmission timing adjusted between the radio communication apparatuses 10 and 20, the influence of intersymbol interference in the combined signal is reduced, and reception characteristics are improved.
  • FIG. 3 is a diagram for explaining the reception timing in the wireless communication apparatus.
  • an OFDM signal is received and processed using an FFT window.
  • 3A and 3B time is shown in the horizontal direction, and OFDM symbol reception timing in the wireless communication apparatuses 10 and 20 is shown in order from the top.
  • the transmission timing is determined so that the received OFDM symbol of the wireless communication apparatus 10 fits in the received FFT window.
  • the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region A.
  • the transmission timing is determined so that the transmission timing is earlier than the state of FIG. 3 (A) and the received OFDM symbol of the wireless communication device 20 is within the reception FFT window.
  • the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region B.
  • FIG. 4 is a diagram for explaining reception characteristics in the wireless communication devices 10 and 20.
  • SINR is used as the reception quality.
  • the vertical axis represents SINR, and the horizontal axis represents reception timing.
  • the timing is shown as a relative value when the effective OFDM symbol length is 1 and the timing T1 in the state where the received OFDM symbol is within the reception FFT window in the wireless communication apparatus 10 is 0.
  • FIG. 4 shows the SINR (indicated by “ ⁇ ” in FIG. 4) of the signal received by the wireless communication device 10 when the transmission timing is changed from the state M to the state N.
  • the SINR of the signal (indicated by “ ⁇ ” in FIG. 4) and the SINR of the combined received signal (indicated by “ ⁇ ” in FIG. 4) are shown. Note that the SINR of each of the wireless communication devices 10 and 20 is measured in a state in which the received OFDM symbol is controlled to be within the reception FFT window by timing control for each of the wireless communication devices 10 and 20.
  • the SINR of the wireless communication apparatus 10 becomes a value R1 in the state of FIG. 3A in which the received OFDM symbol at the timing T1 is within the reception FFT window, and is illustrated from the state of FIG.
  • SINR decreases due to an increase in intersymbol interference.
  • the SINR of the wireless communication device 20 becomes the value R2 ( ⁇ R1) in the state of FIG. 3B in which the received OFDM symbol at the timing T2 is within the reception FFT window, and from the state of FIG.
  • the RINR decreases due to an increase in intersymbol interference.
  • the SINR of the combined received signal takes the maximum value R3 in the state of FIG. 3A at timing T1.
  • the wireless communication device 10 with the highest reception quality among the wireless communication devices 10 and 20 is determined as the reference wireless communication device as the transmission timing that maximizes the reception quality of the combined received signal.
  • the wireless communication device with the highest reception quality is obtained, for example, by obtaining the SINR in each wireless communication device and adding it to all the wireless communication devices.
  • the cell ID of the wireless communication device 10 is transmitted to the wireless communication device 30 as a reference wireless communication device, and a predetermined transmission from the wireless communication device 30 to the wireless communication device 10 as a reference transmission timing.
  • Data is transmitted to the wireless communication devices 10 and 20 at the timing.
  • FIG. 5 is a diagram illustrating a configuration of a wireless communication system 50 according to the second embodiment.
  • the wireless communication system 50 includes a plurality of base stations 60, 80, 90 and a mobile station 100.
  • the base stations 60, 80, and 90 form cells C11, C12, and C13, respectively, and the mobile station 100 is located in the cell C11.
  • Base stations 60, 80, and 90 communicate with each other and perform CoMP communication with mobile station 100.
  • Base station 60 is a serving base station, and base stations 80 and 90 are cooperative base stations.
  • the base stations 60, 80, and 90 perform uplink CoMP communication, and perform processing of receiving and combining the data transmitted by the mobile station 100 in cooperation with the base stations 60, 80, and 90.
  • FIG. 6 is a diagram illustrating a functional configuration of the base station 60.
  • the base station 60 includes a reception antenna 61, a data reception unit 62, a RACH (Random Access Channel) reception unit 63, and an SRS (Sounding Reference Signal) reception unit 64.
  • the base station 60 includes a transmission antenna 65, a control channel transmission unit 66, and a data channel transmission unit 67.
  • the base station 60 includes a data demodulator 68, a data decoder 69, a reception buffer 70, and a transmission buffer 71.
  • the base station 60 includes a timing detection unit 72, a reception quality measurement unit 73, a scheduler unit 74, a UL grant (UpLink grant) generation unit 75, a TA (Timing Advance) command and a RAR (Random Access Response) generation. Part 76.
  • a timing detection unit 72 receives signals and data from the base station 60 and a reception quality measurement unit 73.
  • a scheduler unit 74 receives a UL grant (UpLink grant) generation unit 75
  • TA Timing Advance
  • RAR Random Access Response
  • the data reception unit 62 receives uplink data transmitted from the mobile station 100 via the reception antenna 61.
  • uplink data is transmitted from the mobile station 100 using PUSCH (PhysicalPhysUplink Shared CHannel).
  • the RACH receiving unit 63 receives a random access signal transmitted from the mobile station 100 using the RACH via the receiving antenna 61.
  • Random access is a procedure for transmitting data from one wireless communication device (for example, a mobile station) to the other wireless communication device (for example, a base station) from a state where wireless resources used for data transmission are not allocated. It is.
  • the base station 60 establishes synchronization with the mobile station 100 by receiving the random access signal.
  • the SRS receiving unit 64 receives the SRS from the mobile station 100 via the receiving antenna 61.
  • the SRS is a known signal transmitted by the mobile station 100, and the base station 60 grasps the channel quality and the like by receiving the SRS. Moreover, the base station 60 determines the transmission timing from the mobile station 100 to the base station 60 by receiving SRS.
  • the data demodulator 68 receives the received data from the data receiver 62 and performs a demodulation process.
  • data received from the mobile station 100 is demodulated based on a channel estimation result for PUSCH estimated using DM-RS (DeModulation RS) transmitted from the mobile station 100 as a reference signal.
  • DM-RS Demonulation RS
  • the data decoder 69 receives the data demodulated by the data demodulator 68, performs a decoding process, and stores the acquired data in the reception buffer 70.
  • the timing detector 72 detects the current reception timing of the local station based on the random access signal received by the RACH receiver 63.
  • the timing detection unit 72 detects the current reception timing of the local station based on the SRS received by the SRS reception unit 64.
  • the timing detection unit 72 acquires timing information of the base stations 80 and 90 from the base stations 80 and 90. For example, the timing detector 72 acquires timing information detected by the timing detectors of the base stations 80 and 90 based on the SRS received by the SRS receivers of the base stations 80 and 90.
  • the reception quality measurement unit 73 measures the reception quality of the local station using the SRS received by the SRS reception unit 64. Further, the reception quality measuring unit 73 acquires information indicating the reception quality measured by the reception quality measuring unit of the base stations 80 and 90 from the base stations 80 and 90.
  • the scheduler unit 74 performs scheduling processing such as resource allocation based on the reception quality and timing information of the base stations 60, 80, and 90. For example, the scheduler unit 74 determines SRS resource allocation information for transmitting SRS from the mobile station 100 to the base station 60. For example, the scheduler unit 74 acquires SRS resource allocation information for transmitting SRS from the mobile station 100 to the base stations 80 and 90.
  • the SRS resource allocation information includes, for example, time and frequency at which SRS can be transmitted, and SRS data series information.
  • the scheduler unit 74 may adjust the SRS resource allocation information of the base stations 60, 80, 90 so that the SRSs of the base stations 60, 80, 90 do not collide. Further, for example, the scheduler unit 74 determines a transmission timing serving as an uplink reference from the mobile station 100 to the base stations 60, 80, and 90 during CoMP communication.
  • the UL grant generation unit 75 generates an UL grant indicating a control signal for allocating uplink resources based on the scheduling information by the scheduler unit 74.
  • the UL grant includes SRS resource allocation information from the mobile station 100 to the base stations 60, 80, and 90. Further, UL grant includes information indicating transmission timing that serves as a reference from the mobile station 100 to the base stations 60, 80, and 90. In the second embodiment, the cell ID of the reference base station is used as the information indicating the reference transmission timing.
  • the TA command / RAR generator 76 generates a random access response RAR based on the reception result of the random access signal.
  • the RAR includes timing adjustment information based on the timing information detected by the timing detection unit 72 according to the random access signal.
  • the timing adjustment information includes, for example, the transmission timing of the mobile station 100 from the current time so that the timing at which the signal transmitted from the mobile station 100 is received by the base station 60 is within a predetermined reception window of the base station 60. Indicates whether to make it early or late.
  • the TA command / RAR generator 76 generates a TA command based on the timing information detected by the timing detector 72 according to the SRS received by the SRS receiver 64.
  • the TA command indicates how much the transmission timing from the mobile station 100 should be made earlier or later than the current transmission timing. For example, the base station 60 determines at which timing position in the reception window the SRS is received, and determines the TA command to return to the window center when the reception timing position of the SRS is likely to protrude from the reception window. To do.
  • the control channel transmission unit 66 transmits control information to the mobile station 100 using the control channel via the transmission antenna 65.
  • the control channel includes PDCCH (Physical Downlink Control CHannel).
  • the control information includes a UL custom-character generated by the UL custom-character generating unit 75.
  • the data channel transmission unit 17 transmits data to the mobile station 100 through the transmission antenna 65 using the data channel.
  • the data channel includes PDSCH (Physical Downlink Shared CHannel).
  • the transmission data includes data stored in the transmission buffer 71 and TA command / RAR generated by the TA command / RAR generation unit 76.
  • FIG. 7 is a diagram illustrating a functional configuration of the mobile station 100.
  • the mobile station 100 includes a transmission antenna 101, a data transmission unit 102, an SRS transmission unit 103, and a RACH transmission unit 104.
  • the mobile station 100 includes a reception antenna 105, a control channel reception unit 106, and a data channel reception unit 107.
  • the mobile station 100 includes application processing units 109 and 110, a transmission buffer 108, and a reception buffer 111.
  • the mobile station 100 includes a data sequence generation unit 112, a transmission timing control unit 113, a UL grant analysis unit 114, and an upper layer control information analysis unit 115. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the control channel receiving unit 106 receives control information transmitted from the base station 60 using the control channel via the reception antenna 105.
  • the control channel includes PDCCH (Physical Downlink Control CHannel).
  • the control information includes UL grant.
  • the data channel receiving unit 107 receives data transmitted from the base station 60 using the data channel via the receiving antenna 105.
  • the data channel includes PDSCH (Physical Downlink Shared CHannel).
  • the data channel receiving unit 107 uses the control information received by the control channel 106 to perform demodulation processing, decoding processing, and the like of the received data, and stores in the reception buffer 110 and inputs to the higher layer control information analysis unit 115 I do.
  • the upper layer control information analyzing unit 115 acquires the upper layer control information received by the data channel receiving unit 107.
  • Upper layer control information includes RACH resource allocation information, SRS resource allocation information, and TA commands.
  • the TA command is included in the header area of the decoded received data.
  • the UL grant analysis unit 114 analyzes the UL grant received by the control channel reception unit 106 and acquires information.
  • the acquired information includes information regarding the transmission timing used as a reference.
  • the transmission timing control unit 113 performs transmission via the RACH based on the TA command acquired by the upper layer control information analysis unit 115 and information on the transmission timing used as a reference acquired by the UL grant analysis unit 114, and SRS. The transmission timing of data transmission and data transmission is controlled.
  • the data sequence generation unit 112 generates a data sequence used for the random access preamble and SRS based on the RACH resource allocation information and the SRS resource allocation information.
  • the data transmission unit 102 transmits the data stored in the transmission buffer 108 to the base stations 60, 80, 90 via the transmission antenna 101.
  • the transmission data is transmitted using, for example, PUSCH.
  • the SRS transmission unit 103 transmits the SRS to the base stations 60, 80, 90 using the transmission timing set in the transmission timing control unit 113.
  • the RACH transmission unit 104 transmits a signal using the RACH using the transmission timing set in the transmission timing control unit 113.
  • the application processing unit 109 generates data to be transmitted and stores it in the transmission buffer 108.
  • the application processing unit 110 acquires and processes the reception data stored in the reception buffer 111.
  • FIG. 8 is a diagram illustrating a hardware configuration of the base station 60.
  • the base station 60 includes, as hardware components, for example, a DSP 60A, an FPGA 60B, a memory 60C, an RF circuit 60D including an antenna A1, and a network IF 60E.
  • the DSP 60A and the FPGA 60B are connected so that various signals and data can be input / output via a network IF 60E such as a switch.
  • the memory 60C includes, for example, a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data.
  • the data demodulating unit 68, the data decoding unit 69, the timing detecting unit 72, the reception quality measuring unit 73, the scheduler unit 74, the UL grant generating unit 75, and the TA command / RAR generating unit 76 are, for example, integrated circuits such as a DSP 60A and FPGA 60B. Realized.
  • the data receiving unit 62, the RACH receiving unit 63, the SRS receiving unit 64, the control channel transmitting unit 66, and the data channel transmitting unit 67 are realized by, for example, the RF circuit 60D.
  • the reception buffer 70 and the transmission buffer 71 are realized by the memory 60C, for example.
  • FIG. 9 is a diagram illustrating a hardware configuration of the mobile station 100.
  • the mobile station 100 includes, as hardware components, for example, a CPU 100A, a memory 100B, an RF circuit 100C including an antenna A2, and a display device 100D such as an LCD (Liquid Crystal Display).
  • the memory 100B includes, for example, a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data.
  • the data transmission unit 102, SRS transmission unit 103, RACH transmission unit 104, control channel reception unit 106, and data channel reception unit 107 are realized by, for example, the RF circuit 100C.
  • the application processing units 109 and 110, the data series generation unit 112, the transmission timing control unit 113, the UL grant analysis unit 114, and the higher layer control information analysis unit 115 are realized by an integrated circuit such as the CPU 100A, for example.
  • the transmission buffer 108 and the reception buffer 111 are realized by the memory 100B, for example.
  • 10 and 11 are sequence diagrams for explaining the operation of the wireless communication system 50.
  • the mobile station 100 transmits a random access signal for initial synchronization to the base station 60 (S11).
  • the mobile station 100 uses a signal sequence randomly selected from a plurality of signal sequences by the data sequence generation unit 112 based on system information transmitted using BCH (Broadcast ⁇ ⁇ CHannel) as a random access preamble. Transmit to the base station 60.
  • BCH Broadcast ⁇ ⁇ CHannel
  • a signal transmitted via the RACH is set to have a long CP length, and the allowable range of the reception timing deviation is relatively large. Therefore, it is possible to receive even when the initial timing control is not performed. ing.
  • the base station 60 can grasp the current reception timing of its own station by receiving the random access signal.
  • the base station 60 transmits RAR as a response to the received random access signal (S12).
  • RAR includes timing adjustment information of uplink transmission timing.
  • the mobile station 100 determines the next transmission timing based on this timing adjustment information. As a result, synchronization is established between the base station 60 and the mobile station 100.
  • the base station 60 transmits a message for starting CoMP communication to the mobile station 100 (S13).
  • This message includes cell ID allocation information of the cooperative base stations 80 and 90, for example.
  • the base station 60 notifies the base stations 80 and 90 of information necessary for CoMP communication. Note that the process of selecting a cooperative base station may be performed by the mobile station 100.
  • the mobile station 100 establishes synchronization with the coordinated base stations 80 and 90 (S14 to S17).
  • the mobile station 100 performs random access transmission for initial synchronization to the base station 80 (S14).
  • the RACH resource allocation information uses BCH or PUCCH
  • the base station 80 transmits an RAR including uplink transmission timing adjustment information as a response to the received random access preamble (S15).
  • the mobile station 100 performs random access transmission for initial synchronization to the base station 90 (S16).
  • the base station 90 transmits an RAR including uplink transmission timing adjustment information to the base station 90 as a response to the received random access preamble (S17).
  • initial synchronization of transmission timing is performed between the mobile station 100 and each base station 60, 80, 90, and the initial value of the transmission timing to each base station 60, 80, 90 is stored.
  • the base station 80 notifies the SRS resource allocation information to the base station 60 (S18). Further, the base station 90 notifies the SRS resource allocation information to the base station 60 (S19).
  • the base station 60 transmits the SRS resource allocation information of the base stations 60, 80, 90 to the mobile station 100 (S20).
  • the SRS resource allocation information may be directly transmitted from the base stations 60, 80, 90 to the mobile station 100.
  • the base stations 60, 80, and 90 periodically repeat uplink transmission timing update processing in order (S21 to S28).
  • the uplink transmission timing update process is performed in the transmission cycle of the upper layer control information using the data channel.
  • the upper layer control information is transmitted at a period of 80 [ms], 160 [ms], or 320 [ms], for example.
  • the mobile station 100 transmits an SRS to the base station 60 (S21), and the base station 60 generates a TA command and transmits it to the mobile station 100 (S22). Further, the mobile station 100 transmits an SRS to the base station 80 (S23), the base station 80 generates a TA command and notifies the base station 60 (S24), and the base station 60 transmits the notified TA command. It transmits to the mobile station 100 (S25). Also, the mobile station 100 transmits an SRS to the base station 90 (S26), generates a TA command and notifies the base station 60 (S27), and the base station 60 transmits the notified TA command to the mobile station 100. (S28).
  • the mobile station 100 updates the stored transmission timing to each of the base stations 60, 80, 90 in accordance with the received TA command.
  • the mobile station 100 performs the next transmission to the base stations 60, 80, and 90 using the updated transmission timing.
  • the TA commands may be directly transmitted from the base stations 60, 80, 90 to the mobile station 100.
  • the mobile station 100 transmits SRSs to the base stations 60, 80, and 90, respectively (S29 to S31).
  • the base stations 60, 80, 90 cooperate to measure and acquire the reception quality (S32).
  • the base stations 60, 80, and 90 measure the reception quality using the received SRS as a reference signal.
  • the base station 60 acquires information on the reception quality of the base stations 80 and 90 and timing information from the base stations 80 and 90.
  • the base stations 60, 80, and 90 cooperate to determine information regarding transmission timing that is a reference when data is transmitted from the mobile station 100 (S33). For example, the base station 60 determines a base station serving as a reference for transmission timing based on the information regarding the reception quality of the base stations 60, 80, 90 and the timing information (S33). Thereby, the reference transmission timing is adjusted between the base stations 60, 80, and 90 and appropriately determined.
  • the base station 60 transmits information related to the reference transmission timing to the mobile station 100 (S34). For example, the base station 60 generates a UL custom-character including the cell ID of the base station serving as a reference, and transmits the generated UL custom-character to the mobile station 100.
  • UL grant transmission using the control channel is performed in a shorter cycle than transmission of higher layer control information. For example, UL grant is transmitted at a cycle of 1 [ms]. Since the transmission timing is controlled in such a relatively short cycle, uplink transmission can be performed at a transmission timing that appropriately follows changes in the propagation environment.
  • the mobile station 100 transmits data to the base stations 60, 80, 90 at the transmission timing that is the received reference (S35). Thereby, data is transmitted at an appropriate transmission timing adjusted between the base stations 60, 80 and 90. Data transmitted from the mobile station 100 is received by the base stations 60, 80, and 90, respectively.
  • the base stations 60, 80, 90 cooperate to synthesize signals received at the base stations 60, 80, 90 to acquire data (S36).
  • the base station 60 acquires signals received by the base stations 80 and 90, and combines the signals received by the base stations 60, 80, and 90 to acquire data. Since data is transmitted at the transmission timing adjusted between the base stations 60, 80, 90, the influence of intersymbol interference is reduced in the combined received signal, and reception characteristics are improved.
  • FIG. 12 is a diagram for explaining reception timings at the base stations 60, 80, 90.
  • an OFDM signal is received and processed using an FFT window.
  • the horizontal direction indicates time, and the OFDM symbol reception timing in the base stations 60, 80, and 90 in order from the top.
  • the transmission timing is determined so that the received OFDM symbol of the base station 60 fits in the received FFT window.
  • the received OFDM symbols do not fit in the received FFT window, and intersymbol interference occurs in the regions C and D.
  • the transmission timing is determined so that the transmission timing is advanced from the state of FIG. 12A, and the received OFDM symbol of the base station 80 fits in the reception FFT window. At this time, in the base stations 60 and 90, the received OFDM symbols do not fit in the received FFT window, and intersymbol interference occurs in the regions E and F.
  • the transmission timing is determined so that the transmission timing is earlier than the state of FIG. 12B, and the received OFDM symbol of the base station 90 fits in the reception FFT window.
  • the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region G.
  • FIG. 13 is a diagram for explaining the reception characteristics at the base stations 60, 80, 90.
  • SINR is used as the reception quality.
  • the vertical axis represents SINR, and the horizontal axis represents reception timing.
  • the timing is a relative value when the effective OFDM symbol length is 1, and the timing T3 in the state where the received OFDM symbol is within the received FFT window at the base station 60 is 0.
  • FIG. 13 illustrates the SINR (indicated by “ ⁇ ” in FIG. 13) of the signal received by the base station 60 and the SINR of the signal received by the base station 80 when the transmission timing is changed from the state P to the state R. 13, the SINR of the signal received by the base station 90 (indicated by “X” in FIG. 13), and the SINR of the combined received signal (indicated by “ ⁇ ” in FIG. 13). ).
  • the SINR of each of the base stations 60, 80, 90 is measured in a state where the received OFDM symbols are controlled to be within the reception FFT window by the timing control for each of the base stations 60, 80, 90.
  • the SINR of the base station 60 becomes the value R4 in the state of FIG. 12A where the received OFDM symbol at the timing T3 is within the received FFT window, and from the state of FIG. As the state changes to (C), the SINR decreases due to the increase in intersymbol interference.
  • the SINR of the base station 80 is the maximum value R5 ( ⁇ R4) in the state of FIG. 12B in which the received OFDM symbol at the timing T4 is within the received FFT window.
  • the SINR of the base station 90 is a value R6 ( ⁇ R5) in the state of FIG. 12C in which the received OFDM symbol at timing T5 is within the received FFT window.
  • the SINR of the combined received signal is the maximum value R7 in the state of FIG. 12B at timing T4.
  • the base station 80 of the base stations 60, 80, 90 is determined as a reference base station as the transmission timing that maximizes the reception quality of the combined received signal.
  • the reception quality and the distribution of the reception timing it is more possible to make the symbol closer to the timing of the base stations 80 and 90 where the reception timing is densely distributed than to match the timing of the base station 60 having the highest reception quality. The effect of reducing the influence of interfering interference is great.
  • the cell ID of the base station 80 is transmitted as the reference base station to the mobile station 100, and the mobile station 100 transmits the reference transmission timing to the base station 80 at a predetermined transmission timing as the reference transmission timing.
  • Data is transmitted from 100 to the base stations 60, 80, 90. Thereby, when data is acquired by combining the signals received by the base stations 60, 80, 90, the influence of intersymbol interference is reduced in the combined received signal, and reception characteristics are improved.
  • reception characteristics can be improved in the radio communication system 50 that performs uplink CoMP communication.
  • a value obtained by correcting the reception quality with a predetermined value corresponding to the distribution of the reception timing is used as an index value.
  • the transmission timing may be determined.
  • the reception quality is multiplied by a coefficient corresponding to the relative value based on the median or average value of the reception timing, or an offset value corresponding to the relative value based on the median or average value of the reception timing is added to the reception quality. You may do it.
  • the reception quality is multiplied by a coefficient according to the order close to the median or average value of the reception timing, or an offset value according to the order close to the median or average value of the reception timing is added to the reception quality. May be.
  • FIG. 14 is a diagram illustrating a configuration of a wireless communication system 200 according to the third embodiment.
  • the wireless communication system 200 includes a mobile station 100 and base stations that form a cell.
  • the base station includes a plurality of RRHs (Remote Radio Heads) 230A to 230C and a BBU (BaseBand Unit) 220.
  • RRHs Remote Radio Heads
  • BBU BaseBand Unit
  • Each of the RRHs 230A to 230C has an antenna (point) and is arranged at a distant point to form cover areas E21, 22 and 23.
  • the cell of the base station is formed by the cover areas E21, 22 and 23.
  • the BBU 220 is disposed at a point distant from the RRHs 230A to 230C, and is connected to the RRHs 230A to 230C by wired connection.
  • the mobile station 100 is located in the cover area E21 of the RRH 230A.
  • the RRHs 230A to 230C correspond to an example of a first wireless communication device, and perform communication with each other and CoMP communication with the mobile station 100.
  • Cover area E21 of RRH 230A is used as a serving cell, and cover areas E22 and E23 of RRH 230B and 230C are used as cooperative cells.
  • the RRHs 230A to 230C perform uplink CoMP communication, and perform processing of receiving and combining the data transmitted by the mobile station 100 in cooperation with the RRHs 230A to 230C. Since the configuration and operation of the mobile station 100 are the same as those of the mobile station 100 of the second embodiment, the same reference numerals are given and description thereof is omitted.
  • FIG. 15 is a diagram showing a functional configuration of the RRHs 230A to 230C and the BBU 220 of the base station 210.
  • the RRH 230A of the base station 210 includes a reception antenna 231A, a transmission antenna 232A, and a radio unit 233A.
  • the radio unit 233A includes a data receiver 234A, a RACH receiver 235A, an SRS receiver 236A, a control channel transmitter 237A, and a data channel transmitter 238A.
  • the BBU 220 includes a data demodulator 240, a data decoder 241, a timing detector 243, a reception buffer 242, a reception quality measurement unit 244, a scheduler unit 245, a UL grant generation unit 246, a TA command A RAR generator 247 and a transmission buffer 248 are provided. Details of the components of the RRH 230A and the BBU 220 are the same as those of the components of the base station 60 of the second embodiment.
  • the RRH 230B includes a reception antenna 231B, a transmission antenna 232B, and a radio unit 233B.
  • the radio unit 233B includes a data reception unit 234B, a RACH reception unit 235B, an SRS reception unit 236B, a control channel transmission unit 237B, and a data channel transmission unit 238A. Details of each component of the RRH 230B are the same as each component of the RRH 230A.
  • the RRH 230C includes a reception antenna 231C, a transmission antenna 232C, and a radio unit 233C.
  • the radio unit 233C includes a data reception unit 234C, a RACH reception unit 235C, an SRS reception unit 236C, a control channel transmission unit 237C, and a data channel transmission unit 238C. Details of each component of the RRH 230C are the same as each component of the RRH 230A.
  • the operation of the wireless communication system 200 is basically the transmission / reception operation of the base stations 60, 80, 90 of the second embodiment as the operation of the RRHs 230A-230C.
  • the control operation of the base stations 60, 80, 90 Is the operation of the BBU 220.
  • the base station 60 takes the initiative to acquire information from the base stations 80 and 90 and perform cooperative processing (S32, S33, S36), whereas in the third embodiment, the BBU 220 performs information processing. Aggregate and perform cooperative processing.
  • timing control is executed in the same manner as in the description of FIG. 13 of the second embodiment.
  • a reference transmission timing is determined as the transmission timing that maximizes the reception quality of the combined received signal.
  • FIG. 16 is a diagram illustrating a configuration of a wireless communication system 300 according to the fourth embodiment.
  • base stations 310, 320, and 330 and RRHs 340A to 340L are mixed as an example of a first wireless communication apparatus, and at least a part of these perform cooperative communication.
  • a plurality of base stations 310, 320, and 330 form a plurality of cells C31, C32, and C33.
  • a plurality of RRHs 340A to 340L having antennas (points) are arranged in each cell C31, C32, C33.
  • RRHs 340A to 340L each have an antenna and a radio unit, and BBUs including a baseband processing unit and the like are arranged at different positions.
  • RRHs 340A to 340l are arranged at the ends of cells C31, C32, and C33 of base stations 310, 320, and 330, respectively.
  • RRHs 340A to 340l form cover areas E41A to E41L, respectively.
  • BBUs connected to RRHs 340A to 340L are arranged at substantially the same positions as base stations 310, 320, and 330, respectively.
  • the BBUs corresponding to the RRHs 340A to 340L are connected or integrated with the base stations 310, 320, and 330 forming the cells C31, C32, and C33 that are in the area, and between the base stations 310, 320, and 330. Collaborative scheduling is possible.
  • the mobile station 100 is located in the cover area E340A of the RRH 340A under the base station 310. Since the configuration and operation of the mobile station 100 are the same as those of the mobile station 100 of the second embodiment, the same reference numerals are given and description thereof is omitted.
  • the functional configurations and operations of the base stations 310, 320, and 330 are the same as those of the base station 60 of the second embodiment.
  • the functional configurations and operations of the RRHs 340A to 340L are the same as those of the RRH 230A of the third embodiment.
  • timing control is executed in the same manner as in the description of FIG. 13 of the second embodiment. For example, for at least a part of the base stations 310, 320, and 330 that perform uplink CoMP communication and the RRHs 340A to 340L, a transmission timing that serves as a reference is used as a transmission timing that maximizes the reception quality of the combined received signal. It is determined.
  • reception characteristics can be improved in the wireless communication system 300 that performs uplink CoMP communication.
  • the fourth embodiment has been described on the assumption that the cover area of each RRH exists in the same cell, the cover area of each RRH may be present across different cells.
  • the wireless communication systems of the first to fourth embodiments can be realized as, for example, an LTE-A system.
  • the present invention can also be applied to a wireless communication system using a communication method other than LTE-A.
  • wireless communication system for example, it is also possible to apply to a heterogeneous network in which base stations having different transmission powers are mixed or wireless communication devices using different types of communication methods are mixed. .
  • the condition for determining the reference transmission timing is the installation position of each device (wireless communication device, base station, RRH, antenna, etc.), the arrangement relationship with other devices, or They can be updated as appropriate according to the changing factors such as the operation status and radio wave condition of each device.
  • the first to fourth embodiments can be applied to mobile terminals such as mobile phones, smartphones, PDAs (Personal Digital Assistants) as mobile stations.
  • the first to fourth embodiments can be applied to various communication devices that communicate with a base station such as a mobile relay station.
  • first to fourth embodiments can be applied to base stations of various sizes such as macro base stations and femto base stations as base stations.
  • first to fourth embodiments can be applied to various communication devices that communicate with mobile stations such as relay stations.
  • each component of the base station and mobile station is not limited to the mode of the first to fourth embodiments, and all or a part thereof can be used for various loads and usage conditions. Accordingly, it may be configured to be functionally or physically distributed / integrated in an arbitrary unit.
  • the memory may be connected via a network or a cable as an external device of the base station or mobile station.

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Abstract

The purpose of the disclosed technology is to provide a wireless communication system, wireless communication device, and wireless communication method with which it is possible to improve reception characteristics in coordinated multipoint communication. A wireless communication system in which data transmitted from a second wireless communication device is received by a plurality of first wireless communication devices, the wireless communication system comprising: a first transmission unit that transmits, to the second wireless communication device, information that is based on information regarding the plurality of first wireless communication devices and relates to a transmission timing; and a second transmission unit that transmits the data from the second wireless communication device to the plurality of first wireless communication devices at the transmission timing.

Description

無線通信システム、無線通信方法、及び無線通信装置Wireless communication system, wireless communication method, and wireless communication apparatus
　本発明は、無線通信システム、無線通信方法、及び無線通信装置に関する。 The present invention relates to a wireless communication system, a wireless communication method, and a wireless communication apparatus.
　近年、携帯電話システム等の無線通信システムにおいて、無線通信の更なる高速化・大容量化等を図るため、次世代の無線通信技術について議論が行われている。例えば、標準化団体である３ＧＰＰ（3rd Generation Partnership Project）では、ＬＴＥ（Long Term Evolution）と呼ばれる通信規格や、ＬＴＥの無線通信技術をベースとしたＬＴＥ－Ａ（LTE - Advanced）と呼ばれる通信規格が提案されている。 In recent years, next-generation wireless communication technologies have been discussed in order to further increase the speed and capacity of wireless communication in wireless communication systems such as mobile phone systems. For example, 3GPP (3rd Generation Partnership Project), a standardization organization, proposes a communication standard called LTE (Long Term Evolution) and a communication standard called LTE-A (LTE-Advanced) based on LTE wireless communication technology. Has been.
　ＬＴＥ－Ａシステム等において、セル間干渉の低減や受信信号強度の改善のため、多地点協調（Coordinated MultiPoint、以下、ＣｏＭＰともいう）通信が検討されている。多地点協調通信では、地理的に離れた複数のポイントが協調して通信を行う。各ポイントは、例えば、基地局、アンテナ或いはこれらにより形成されるセルに相当する。これにより、多地点間での送信あるいは受信のダイナミックな調整が行われる。例えば、上りリンクの多地点協調通信では、複数のセルで受信された信号をセル間で通信しながら結合処理する方法が検討されている。 In the LTE-A system etc., coordinated multipoint (hereinafter also referred to as CoMP) communication is being studied in order to reduce inter-cell interference and improve received signal strength. In multipoint cooperative communication, a plurality of geographically distant points cooperate to perform communication. Each point corresponds to, for example, a base station, an antenna, or a cell formed by these. Thereby, dynamic adjustment of transmission or reception between multiple points is performed. For example, in uplink multipoint cooperative communication, a method of combining signals while receiving signals received in a plurality of cells is being studied.
　しかしながら、多地点協調通信によりセル間干渉の低減や受信信号強度の改善を実現するためには、制御の遅延やシグナリングの増大の考慮のもとで、セル間での適切な調整が必要である。例えば上りリンクの多地点協調通信で、端末から送信される信号を受信するタイミングがセル毎に異なることが想定される。このとき、セル間の受信タイミングによっては、上りリンクの多地点協調通信の結合処理で、シンボル間干渉の影響が増大して受信特性の向上を阻害する恐れがある。 However, in order to reduce inter-cell interference and improve received signal strength through multipoint coordinated communication, appropriate adjustments between cells are necessary in consideration of control delay and increased signaling. . For example, in uplink multipoint cooperative communication, it is assumed that the timing for receiving a signal transmitted from a terminal is different for each cell. At this time, depending on the reception timing between the cells, there is a possibility that the influence of inter-symbol interference increases and the improvement of the reception characteristics may be hindered by the combination processing of uplink multipoint cooperative communication.
　開示の技術は、上記に鑑みてなされたものであって、多地点協調通信において、受信特性を向上することのできる無線通信システム、無線通信装置、及び無線通信方法を提供することを目的とする。 The disclosed technology has been made in view of the above, and an object thereof is to provide a wireless communication system, a wireless communication apparatus, and a wireless communication method capable of improving reception characteristics in multipoint cooperative communication. .
　上述した課題を解決し、目的を達成するために、本件の開示する無線通信システムは、一つの態様において、複数の第１の無線通信装置で、第２の無線通信装置から送信されるデータを受信する。前記複数の第１の無線通信装置に関する情報に基づく、送信タイミングに関する情報を、前記第２の無線通信装置に送信する第１の送信部と、前記第２の無線通信装置から前記複数の第１の無線通信装置に、前記送信タイミングで前記データを送信する第２の送信部と、を有する。 In order to solve the above-described problems and achieve the object, in one aspect, a wireless communication system disclosed in the present application is a plurality of first wireless communication devices that transmit data transmitted from a second wireless communication device. Receive. A first transmission unit that transmits information related to transmission timing based on information about the plurality of first wireless communication devices to the second wireless communication device, and the plurality of first wireless communication devices from the second wireless communication device. A second transmission unit that transmits the data at the transmission timing.
　本件の開示する無線通信システムの一つの態様によれば、上りリンクの多地点協調通信において、受信特性を向上することができるという効果を奏する。 According to one aspect of the wireless communication system disclosed in the present case, it is possible to improve reception characteristics in uplink multipoint cooperative communication.
図１は、第１実施形態に係る無線通信システムの構成を示す図である。FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment. 図２は、無線通信システムの動作を説明するためのシーケンス図である。FIG. 2 is a sequence diagram for explaining the operation of the wireless communication system. 図３は、無線通信装置での受信タイミングを説明するための図である。FIG. 3 is a diagram for explaining the reception timing in the wireless communication apparatus. 図４は、無線通信装置での受信特性を説明するための図である。FIG. 4 is a diagram for explaining reception characteristics in the wireless communication device. 図５は、第２実施形態に係る無線通信システムの構成を示す図である。FIG. 5 is a diagram illustrating a configuration of a wireless communication system according to the second embodiment. 図６は、基地局の機能的構成を示す図である。FIG. 6 is a diagram illustrating a functional configuration of the base station. 図７は、移動局の機能的構成を示す図である。FIG. 7 is a diagram illustrating a functional configuration of the mobile station. 図８は、基地局のハードウェア構成を示す図である。FIG. 8 is a diagram illustrating a hardware configuration of the base station. 図９は、移動局のハードウェア構成を示す図である。FIG. 9 is a diagram illustrating a hardware configuration of the mobile station. 図１０は、無線通信システムの動作を説明するためのシーケンス図である。FIG. 10 is a sequence diagram for explaining the operation of the wireless communication system. 図１１は、無線通信システムの動作を説明するためのシーケンス図である。FIG. 11 is a sequence diagram for explaining the operation of the wireless communication system. 図１２は、基地局での受信タイミングを説明するための図である。FIG. 12 is a diagram for explaining the reception timing at the base station. 図１３は、基地局での受信特性を説明するための図である。FIG. 13 is a diagram for explaining reception characteristics at the base station. 図１４は、第３実施形態に係る無線通信システムの構成を示す図である。FIG. 14 is a diagram illustrating a configuration of a wireless communication system according to the third embodiment. 図１５は、ＲＲＨ（Remote　Radio　Head）の機能的構成を示す図である。FIG. 15 is a diagram illustrating a functional configuration of RRH (Remote Radio Head). 図１６は、第４実施形態に係る無線通信システムの構成を示す図である。FIG. 16 is a diagram illustrating a configuration of a wireless communication system according to the fourth embodiment.
　以下に、本件の開示する無線通信システム、無線通信方法、及び無線通信装置の実施例を、図面を参照しながら説明する。なお、以下の実施例により本件の開示する無線通信システム、無線通信方法、及び無線通信装置が限定されるものではない。
［第１実施形態］
　図１は、第１実施形態に係る無線通信システム１の構成を示す。図１に示すように、無線通信システム１は、複数の無線通信装置１０，２０と、無線通信装置３０とを含む。例えば、無線通信システム１は、無線通信装置１０，２０を基地局、無線通信装置３０を移動局として実現できる。無線通信装置１０，２０は、セルＣ１、Ｃ２をそれぞれ形成しており、無線通信装置３０は、セルＣ１に在圏している。無線通信装置１０，２０は、無線通信装置１０，２０間で有線接続あるいは無線接続を介して通信を行うと共に、無線通信装置３０に対してＣｏＭＰ通信を行う。無線通信装置１０，２０は、上りリンクのＣｏＭＰ通信を行っており、無線通信装置３０が送信するデータを無線通信装置１０，２０で受信し、受信信号を無線通信装置１０，２０間で合成する処理を行う。このように受信信号を無線通信装置１０，２０間で合成することで、セル間干渉の低減や受信信号強度の改善を行い受信特性の向上を図っている。 Embodiments of a wireless communication system, a wireless communication method, and a wireless communication apparatus disclosed in the present application will be described below with reference to the drawings. Note that the wireless communication system, the wireless communication method, and the wireless communication device disclosed in the present application are not limited by the following embodiments.
[First Embodiment]
FIG. 1 shows a configuration of a wireless communication system 1 according to the first embodiment. As shown in FIG. 1, the wireless communication system 1 includes a plurality of wireless communication devices 10 and 20 and a wireless communication device 30. For example, the wireless communication system 1 can be realized by using the wireless communication devices 10 and 20 as a base station and the wireless communication device 30 as a mobile station. The wireless communication devices 10 and 20 form cells C1 and C2, respectively, and the wireless communication device 30 is located in the cell C1. The wireless communication devices 10 and 20 perform communication between the wireless communication devices 10 and 20 via wired connection or wireless connection, and perform CoMP communication with the wireless communication device 30. The radio communication devices 10 and 20 perform uplink CoMP communication, receive data transmitted by the radio communication device 30 by the radio communication devices 10 and 20, and synthesize a reception signal between the radio communication devices 10 and 20. Process. In this way, by combining received signals between the radio communication devices 10 and 20, inter-cell interference is reduced and received signal strength is improved to improve reception characteristics.
　図１に示すように、無線通信装置１０は機能的構成として、アンテナ１１と、送信部１２と、受信部１３と、制御部１４とを備える。これら各構成部分は、一方向又は双方向に、信号やデータの入出力が可能なように接続されている。無線通信装置２０の各構成部分２１～２４は、無線通信装置１０の各構成部分１１～１４と同様である。 As shown in FIG. 1, the wireless communication apparatus 10 includes an antenna 11, a transmission unit 12, a reception unit 13, and a control unit 14 as functional configurations. Each of these components is connected so that signals and data can be input and output in one direction or in both directions. Each component 21 to 24 of the wireless communication device 20 is the same as each component 11 to 14 of the wireless communication device 10.
　制御部１４は、有線接続あるいは無線接続を介して、無線通信装置２０から情報や信号を取得する。制御部１４は、無線通信装置１０，２０に関する情報に基づいて、無線通信装置３０からデータを送信する際に基準となる送信タイミングに関する情報を決定する。無線通信装置１０，２０に関する情報とは、例えば、無線通信装置１０，２０で測定される、無線通信装置１０，２０での受信品質に関する情報や、無線通信装置１０，２０での受信タイミングの分布に関する情報を含む。受信品質は、例えば、ＳＩＲ（Signal to Interference Ratio）、ＳＩＮＲ（Signal to Interference and Noise Ratio）、ＲＳＲＰ（Reference Signal Received Power）、ＲＳＲＱ（Reference Signal Received Power）（＝受信電力値／総電力値）を含む。制御部１４は、無線通信装置１０で受信された信号と、無線通信装置２０で受信された信号とを合成して復号処理等を実行し、無線通信装置３０から送信されたデータを取得する。制御部１４は、無線通信装置１０，２０に関する情報が所定条件を満たすように、上りリンクの基準となる送信タイミングを決定する。制御部１４は、例えば、合成後の信号の受信品質が最も高くなるように、上りリンクの基準となる送信タイミングを決定する。なお、制御部１４は、本件の決定部及び処理部の一例に相当する。また、無線通信装置１０，２０に関する情報は、各無線通信装置１０，２０の種類、設置位置、配置関係、或いは運用状況等、無線通信装置１０，２０に関する様々な情報を含み得る。 The control unit 14 acquires information and signals from the wireless communication device 20 via a wired connection or a wireless connection. The control unit 14 determines information related to transmission timing that is a reference when data is transmitted from the wireless communication device 30 based on the information related to the wireless communication devices 10 and 20. The information related to the wireless communication devices 10 and 20 includes, for example, information related to reception quality at the wireless communication devices 10 and 20 measured by the wireless communication devices 10 and 20, and distribution of reception timings at the wireless communication devices 10 and 20. Contains information about. The reception quality is, for example, SIR (Signal-to-Interference-Ratio), SINR (Signal-to-Interference-and-Noise-Ratio), RSRP (Reference-Signal-Received-Power), RSRQ (Reference-Signal-Received-Power) (= received power value / total power value). Including. The control unit 14 combines the signal received by the wireless communication device 10 and the signal received by the wireless communication device 20 to execute a decoding process or the like, and acquires data transmitted from the wireless communication device 30. The control unit 14 determines a transmission timing serving as an uplink reference so that information regarding the wireless communication apparatuses 10 and 20 satisfies a predetermined condition. For example, the control unit 14 determines a transmission timing serving as an uplink reference so that the reception quality of the combined signal is the highest. The control unit 14 corresponds to an example of a determination unit and a processing unit in this case. Further, the information related to the wireless communication devices 10 and 20 may include various information related to the wireless communication devices 10 and 20 such as the type, installation position, arrangement relationship, or operation status of each wireless communication device 10 and 20.
　送信部１２は、上りリンクの基準となる送信タイミングに関する情報を、アンテナ１１を介して無線通信装置３０に送信する。受信部１３は、無線通信装置３０から基準となる送信タイミングで送信されたデータを、アンテナ１１を介して受信する。なお、アンテナ１１は送信と受信で別体としてもよい。 The transmission unit 12 transmits information related to transmission timing serving as an uplink reference to the wireless communication device 30 via the antenna 11. The receiving unit 13 receives data transmitted from the wireless communication device 30 at a reference transmission timing via the antenna 11. The antenna 11 may be separated for transmission and reception.
　無線通信装置１０は、ハードウェアの構成要素として、例えばＤＳＰ（Digital　Signal　Processor）と、ＦＰＧＡ（Field　Programmable　Gate　Array）と、メモリと、アンテナを備えるＲＦ（Radio　Frequency）回路とを有する。メモリは、例えばＳＤＲＡＭ（Synchronous　Dynamic　Random　Access　Memory）等のＲＡＭ、ＲＯＭ（Read　Only　Memory)、及びフラッシュメモリを含み、プログラムや制御情報やデータを格納する。送信部１２及び受信部１３は、例えばＲＦ回路により実現される。制御部１４は、例えばＤＳＰ、ＦＰＧＡ等の集積回路により実現される。無線通信装置２０のハードウェア構成は、無線通信装置１０と同様である。 The wireless communication device 10 includes, for example, a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), a memory, and an RF (Radio Frequency) circuit including an antenna as hardware components. The memory includes RAM, such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data. The transmission unit 12 and the reception unit 13 are realized by, for example, an RF circuit. The control unit 14 is realized by an integrated circuit such as a DSP or FPGA. The hardware configuration of the wireless communication device 20 is the same as that of the wireless communication device 10.
　また、図１に示すように、無線通信装置３０は機能的構成として、アンテナ３１と、送信部３２と、受信部３３と、制御部３４とを備える。これら各構成部分は、一方向又は双方向に、信号やデータの入出力が可能なように接続されている。 As shown in FIG. 1, the wireless communication device 30 includes an antenna 31, a transmission unit 32, a reception unit 33, and a control unit 34 as functional configurations. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
　受信部３３は、無線通信装置１０から、基準となる送信タイミングに関する情報を受信する。制御部３４は、送信するデータの符号化処理等を実行する。送信部３２は、基準となる送信タイミングでデータを無線通信装置１０，２０に送信する。なお、アンテナ３１は送信と受信で別体としてもよい。 The receiving unit 33 receives information related to the reference transmission timing from the wireless communication device 10. The control unit 34 performs processing such as encoding of data to be transmitted. The transmission unit 32 transmits data to the wireless communication devices 10 and 20 at a reference transmission timing. The antenna 31 may be separated for transmission and reception.
　無線通信装置３０は、ハードウェアの構成要素として、例えばＣＰＵ（Central　Processing　Unit）と、メモリと、アンテナを備えるＲＦ回路とを有する。メモリは、例えばＳＤＲＡＭ等のＲＡＭ、ＲＯＭ、及びフラッシュメモリを含み、プログラムや制御情報やデータを格納する。送信部３２及び受信部３３は、例えばＲＦ回路により実現される。制御部３４は、例えばＣＰＵ等の集積回路により実現される。 The wireless communication device 30 includes, as hardware components, for example, a CPU (Central Processing Unit), a memory, and an RF circuit including an antenna. The memory includes RAM such as SDRAM, ROM, and flash memory, for example, and stores programs, control information, and data. The transmission unit 32 and the reception unit 33 are realized by, for example, an RF circuit. The control unit 34 is realized by an integrated circuit such as a CPU, for example.
　次に、第１実施形態における無線通信システム１の動作を説明する。図２は、無線通信システム１のタイミング制御に関する動作を説明するためのシーケンス図である。前提として、無線通信システム１では、無線通信装置１０，２０はそれぞれ自装置の制御タイミングで受信処理を実行しており、受信信号と受信処理とのタイミング同期は、無線通信装置３０からの上りリンクの送信タイミングを調整することで確立されている。例えば、上りリンクのＣｏＭＰ通信を行わない場合、無線通信装置３０とサービングセルＣ１に対応する無線通信装置１０との間のタイミング同期が、無線通信装置３０からの上りリンクの送信タイミングを、無線通信装置１０の受信処理のタイミングに合うように調整することで確立される。このような調整は、例えば、無線通信装置１０から無線通信装置３０に、上りリンクの送信タイミングを調整するコマンドを送信し、このコマンドに応じて無線通信装置１０が次回の送信を行うことで実行される。 Next, the operation of the wireless communication system 1 in the first embodiment will be described. FIG. 2 is a sequence diagram for explaining an operation related to timing control of the wireless communication system 1. As a premise, in the wireless communication system 1, the wireless communication devices 10 and 20 each perform reception processing at the control timing of its own device, and the timing synchronization between the reception signal and the reception processing is performed by the uplink from the wireless communication device 30. It has been established by adjusting the transmission timing. For example, when uplink CoMP communication is not performed, the timing synchronization between the radio communication device 30 and the radio communication device 10 corresponding to the serving cell C1 indicates that the uplink transmission timing from the radio communication device 30 is the same as the radio communication device. It is established by adjusting to match the timing of 10 reception processes. Such adjustment is executed, for example, by transmitting a command for adjusting the uplink transmission timing from the wireless communication device 10 to the wireless communication device 30 and performing the next transmission by the wireless communication device 10 in response to this command. Is done.
　また、上りリンクのＣｏＭＰ通信を行う場合には、無線通信装置３０は無線通信装置１０，２０に対して、同じ送信タイミングで同じチャネルを用いてデータを送信する。このとき、上りリンクの基準となる送信タイミングによっては、受信信号と受信処理とのタイミング差によるシンボル間干渉の影響が増大して、受信特性の向上を阻害する恐れがある。受信信号と受信処理とのタイミング差とは、例えば、受信信号に含まれるＯＦＤＭ（Orthogonal Frequency Division Multiplexing）シンボルの時間軸上位置と、受信処理で用いるＦＦＴ（Fast Fourier Transform）窓の時間軸上位置との差である。そこで、無線通信システム１では、上りリンクのＣｏＭＰ通信を行う場合、以下のようにタイミング制御を行う。 When performing uplink CoMP communication, the wireless communication device 30 transmits data to the wireless communication devices 10 and 20 using the same channel at the same transmission timing. At this time, depending on the transmission timing serving as an uplink reference, the influence of inter-symbol interference due to the timing difference between the received signal and the reception process may increase, thereby hindering improvement in reception characteristics. The timing difference between the received signal and the received processing is, for example, the position on the time axis of the OFDM (Orthogonal Frequency Division) Multiplexing (OFDM) symbol included in the received signal and the position on the time axis of the FFT (Fast Fourier Transform) window used in the received process. Is the difference. Therefore, in the wireless communication system 1, when performing uplink CoMP communication, timing control is performed as follows.
　図２に示すように、無線通信装置１０，２０は連携して、無線通信装置１０，２０に関する情報を取得する（Ｓ１）。例えば、無線通信装置１０は、無線通信装置１０での受信品質を測定する。また、無線通信装置１０は、無線通信装置２０から、無線通信装置２０で測定される受信品質等の情報を取得する。 As shown in FIG. 2, the wireless communication devices 10 and 20 cooperate to acquire information related to the wireless communication devices 10 and 20 (S1). For example, the wireless communication device 10 measures reception quality at the wireless communication device 10. In addition, the wireless communication device 10 acquires information such as reception quality measured by the wireless communication device 20 from the wireless communication device 20.
　無線通信装置１０，２０は連携して、無線通信装置３０からデータを送信する際の上りリンクの基準となる送信タイミングに関する情報を決定する（Ｓ２）。例えば、無線通信装置１０は、無線通信装置１０，２０に関する受信品質等に関する情報に基づいて、合成後の信号の受信品質が所定条件を満たすように、上りリンクの基準となる送信タイミングに関する情報を決定する。基準となる送信タイミングに関する情報は、例えば無線通信装置１０，２０のうちの基準となる無線通信装置を示す情報を含む。なお、無線通信装置１０は基準となる送信タイミングを決定し、基準となる送信タイミングに関する情報として、基準となる送信タイミング自体を無線通信装置３０に送信してもよい。また、無線通信装置１０から送信される情報に基づいて、無線通信装置３０が基準となる送信タイミングを決定してもよい。これにより、上りリンクの基準となる送信タイミングが、無線通信装置１０，２０間で調整されて適切に決定される。 The wireless communication devices 10 and 20 cooperate to determine information related to transmission timing that serves as an uplink reference when data is transmitted from the wireless communication device 30 (S2). For example, the wireless communication device 10 uses the information related to the reception quality of the wireless communication devices 10 and 20 to transmit the information related to the transmission timing serving as the uplink reference so that the reception quality of the combined signal satisfies the predetermined condition. decide. The information regarding the transmission timing used as a reference | standard contains the information which shows the wireless communication apparatus used as the reference | standard among the wireless communication apparatuses 10 and 20, for example. Note that the wireless communication device 10 may determine a reference transmission timing and transmit the reference transmission timing itself to the wireless communication device 30 as information on the reference transmission timing. Further, based on information transmitted from the wireless communication device 10, the wireless communication device 30 may determine a transmission timing that serves as a reference. Thereby, the transmission timing used as the reference | standard of an uplink is adjusted between the radio | wireless communication apparatuses 10 and 20, and is determined appropriately.
　無線通信装置１０は、基準となる送信タイミングに関する情報を、無線通信装置３０に送信する（Ｓ３）。無線通信装置１０は、例えば、基準となる送信タイミングに関する情報として、無線通信装置１０，２０のうちの基準となる無線通信装置の識別情報（セルＩＤ等）を送信する。無線通信装置３０は、基準となる送信タイミングに関する情報を受信し、基準となる送信タイミングで無線通信装置１０，２０にデータを送信する（Ｓ４）。例えば、基準となる無線通信装置に対して予め定められた送信タイミングで、無線通信装置１０，２０にデータが送信される。これにより、無線通信装置１０，２０間で調整された適切な送信タイミングでデータが送信される。無線通信装置１０から送信されたデータは、無線通信装置１０，２０でそれぞれ受信される。 The wireless communication device 10 transmits information related to the reference transmission timing to the wireless communication device 30 (S3). For example, the wireless communication device 10 transmits identification information (cell ID or the like) of a wireless communication device serving as a reference among the wireless communication devices 10 and 20 as information related to a transmission timing serving as a reference. The wireless communication device 30 receives information related to the reference transmission timing, and transmits data to the wireless communication devices 10 and 20 at the reference transmission timing (S4). For example, data is transmitted to the wireless communication devices 10 and 20 at a predetermined transmission timing with respect to the reference wireless communication device. As a result, data is transmitted at an appropriate transmission timing adjusted between the wireless communication devices 10 and 20. The data transmitted from the wireless communication device 10 is received by the wireless communication devices 10 and 20, respectively.
　無線通信装置１０，２０は連携して、無線通信装置１０で受信された信号と無線通信装置２０で受信された信号とを合成してデータを取得する（Ｓ５）。例えば、無線通信装置１０が、無線通信装置２０で受信された信号を取得し、無線通信装置１０で受信された信号と合成してデータを取得する。無線通信装置１０，２０間で調整された送信タイミングでデータが送信されるので、合成後の信号におけるシンボル間干渉の影響が低減され、受信特性が向上される。 The wireless communication apparatuses 10 and 20 cooperate to synthesize the signal received by the wireless communication apparatus 10 and the signal received by the wireless communication apparatus 20 to acquire data (S5). For example, the wireless communication device 10 acquires a signal received by the wireless communication device 20 and combines it with the signal received by the wireless communication device 10 to acquire data. Since data is transmitted at the transmission timing adjusted between the radio communication apparatuses 10 and 20, the influence of intersymbol interference in the combined signal is reduced, and reception characteristics are improved.
　上記の動作について、図３，図４の例を用いて説明する。図３は、無線通信装置での受信タイミングを説明するための図である。図３の例では、ＯＦＤＭ信号が受信され、ＦＦＴ窓を用いて処理される。図３（Ａ）（Ｂ）は、横方向は時間を示し、上から順に無線通信装置１０，２０におけるＯＦＤＭシンボルの受信タイミングを示す。 The above operation will be described with reference to the examples of FIGS. FIG. 3 is a diagram for explaining the reception timing in the wireless communication apparatus. In the example of FIG. 3, an OFDM signal is received and processed using an FFT window. 3A and 3B, time is shown in the horizontal direction, and OFDM symbol reception timing in the wireless communication apparatuses 10 and 20 is shown in order from the top.
　図３（Ａ）の状態では、無線通信装置１０の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように、送信タイミングが決定されている。このとき、無線通信装置２０では、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まらず、領域Ａでシンボル間干渉が生じる。 In the state of FIG. 3A, the transmission timing is determined so that the received OFDM symbol of the wireless communication apparatus 10 fits in the received FFT window. At this time, in the wireless communication device 20, the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region A.
　図３（Ｂ）の状態では、送信タイミングが図３（Ａ）の状態より早められ、無線通信装置２０の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように、送信タイミングが決定されている。このとき、無線通信装置１０では、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まらず、領域Ｂでシンボル間干渉が生じる。 In the state of FIG. 3 (B), the transmission timing is determined so that the transmission timing is earlier than the state of FIG. 3 (A) and the received OFDM symbol of the wireless communication device 20 is within the reception FFT window. At this time, in the wireless communication apparatus 10, the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region B.
　図４は、無線通信装置１０，２０での受信特性を説明するための図である。図４の例では、受信品質としてＳＩＮＲが用いられる。図４において、縦軸はＳＩＮＲを示し、横軸は受信のタイミングを示す。タイミングは、有効ＯＦＤＭシンボル長を１として、無線通信装置１０で受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている状態のタイミングＴ１を０とした場合の相対値として示す。無線通信装置２０は、タイミングＴ２＝０．２で、無線通信装置２０で受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている状態となる。 FIG. 4 is a diagram for explaining reception characteristics in the wireless communication devices 10 and 20. In the example of FIG. 4, SINR is used as the reception quality. In FIG. 4, the vertical axis represents SINR, and the horizontal axis represents reception timing. The timing is shown as a relative value when the effective OFDM symbol length is 1 and the timing T1 in the state where the received OFDM symbol is within the reception FFT window in the wireless communication apparatus 10 is 0. The wireless communication device 20 is in a state where the received OFDM symbol is within the reception FFT window at the timing T2 = 0.2.
　図４は、送信タイミングを状態Ｍから状態Ｎの状態まで変化させた場合の、無線通信装置１０で受信した信号のＳＩＮＲ（図４にて「□」で示す）、無線通信装置２０で受信した信号のＳＩＮＲ（図４にて「△」で示す）、合成後の受信信号のＳＩＮＲ（図４にて「○」で示す）を示している。なお、各無線通信装置１０，２０のＳＩＮＲは、無線通信装置１０，２０毎のタイミング制御により、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように制御されている状態でそれぞれ測定される。 FIG. 4 shows the SINR (indicated by “□” in FIG. 4) of the signal received by the wireless communication device 10 when the transmission timing is changed from the state M to the state N. The SINR of the signal (indicated by “Δ” in FIG. 4) and the SINR of the combined received signal (indicated by “◯” in FIG. 4) are shown. Note that the SINR of each of the wireless communication devices 10 and 20 is measured in a state in which the received OFDM symbol is controlled to be within the reception FFT window by timing control for each of the wireless communication devices 10 and 20.
　図４に示すように、無線通信装置１０のＳＩＮＲは、タイミングＴ１の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている図３（Ａ）の状態で値Ｒ１となり、図３（Ａ）の状態から図３（Ｂ）の状態に変化するにつれて、シンボル間干渉の増大によりＳＩＮＲが低下している。一方、無線通信装置２０のＳＩＮＲは、タイミングＴ２の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている図３（Ｂ）の状態で値Ｒ２（＜Ｒ１）となり、図３（Ｂ）の状態から図３（Ａ）の状態に変化するにつれて、シンボル間干渉の増大によりＲＩＮＲが低下している。このとき、合成後の受信信号のＳＩＮＲは、タイミングＴ１の図３（Ａ）の状態で最大値Ｒ３をとる。 As shown in FIG. 4, the SINR of the wireless communication apparatus 10 becomes a value R1 in the state of FIG. 3A in which the received OFDM symbol at the timing T1 is within the reception FFT window, and is illustrated from the state of FIG. As the state changes to 3 (B), SINR decreases due to an increase in intersymbol interference. On the other hand, the SINR of the wireless communication device 20 becomes the value R2 (<R1) in the state of FIG. 3B in which the received OFDM symbol at the timing T2 is within the reception FFT window, and from the state of FIG. As the state changes to (A), the RINR decreases due to an increase in intersymbol interference. At this time, the SINR of the combined received signal takes the maximum value R3 in the state of FIG. 3A at timing T1.
　このとき、例えば、合成後の受信信号の受信品質を最も高くする送信タイミングとして、無線通信装置１０，２０のうち受信品質が最も高い無線通信装置１０が、基準となる無線通信装置として決定される。 At this time, for example, the wireless communication device 10 with the highest reception quality among the wireless communication devices 10 and 20 is determined as the reference wireless communication device as the transmission timing that maximizes the reception quality of the combined received signal. .
　なお、受信品質が最も高い無線通信装置は例えば、各無線通信装置でＳＩＮＲを求め、全ての無線通信装置に対して加算することにより求められる。また、各無線通信装置１０，２０のＳＩＮＲは例えば、信号をＳ、雑音をＮ、受信信号のタイミングがＦＦＴ窓からはみ出る割合をαとして、次式（１）
　ＳＩＮＲ＝Ｓ×（１－α）／（Ｎ＋Ｓ×α）…（１）
を用いて算出することができる。 Note that the wireless communication device with the highest reception quality is obtained, for example, by obtaining the SINR in each wireless communication device and adding it to all the wireless communication devices. Further, the SINR of each of the wireless communication devices 10 and 20 is, for example, the following equation (1), where S is a signal, N is a noise, and α is a rate at which the timing of the received signal protrudes from the FFT window
SINR = S × (1−α) / (N + S × α) (1)
Can be used to calculate.
　そして、基準となる無線通信装置として、無線通信装置１０のセルＩＤが無線通信装置３０に送信され、無線通信装置３０から、基準となる送信タイミングとして、無線通信装置１０への予め定められた送信タイミングで、無線通信装置１０，２０へデータが送信される。これにより、無線通信装置１０，２０で受信された信号を合成してデータを取得する際に、合成後の受信信号においてシンボル間干渉の影響が低減され、受信特性が向上される。 Then, the cell ID of the wireless communication device 10 is transmitted to the wireless communication device 30 as a reference wireless communication device, and a predetermined transmission from the wireless communication device 30 to the wireless communication device 10 as a reference transmission timing. Data is transmitted to the wireless communication devices 10 and 20 at the timing. As a result, when the signals received by the wireless communication devices 10 and 20 are combined to acquire data, the influence of intersymbol interference is reduced in the combined received signal, and the reception characteristics are improved.
　以上により、第１実施形態によれば、上りリンクのＣｏＭＰ通信を行う無線通信システム１において、受信特性を向上させることができる。
［第２実施形態］
　図５は、第２実施形態に係る無線通信システム５０の構成を示す図である。図５に示すように、無線通信システム５０は、複数の基地局６０，８０，９０と、移動局１００と、を含む。基地局６０，８０，９０は、セルＣ１１、Ｃ１２、Ｃ１３をそれぞれ形成しており、移動局１００は、セルＣ１１に在圏している。基地局６０，８０，９０は、互いに通信を行うと共に、移動局１００に対してＣｏＭＰ通信を行う。基地局６０をサービング基地局とし、基地局８０，９０を協調基地局とする。基地局６０，８０，９０は、上りリンクのＣｏＭＰ通信を行っており、移動局１００が送信するデータを基地局６０，８０，９０で協調して受信し合成する処理を行う。 As described above, according to the first embodiment, it is possible to improve reception characteristics in the wireless communication system 1 that performs uplink CoMP communication.
[Second Embodiment]
FIG. 5 is a diagram illustrating a configuration of a wireless communication system 50 according to the second embodiment. As shown in FIG. 5, the wireless communication system 50 includes a plurality of base stations 60, 80, 90 and a mobile station 100. The base stations 60, 80, and 90 form cells C11, C12, and C13, respectively, and the mobile station 100 is located in the cell C11. Base stations 60, 80, and 90 communicate with each other and perform CoMP communication with mobile station 100. Base station 60 is a serving base station, and base stations 80 and 90 are cooperative base stations. The base stations 60, 80, and 90 perform uplink CoMP communication, and perform processing of receiving and combining the data transmitted by the mobile station 100 in cooperation with the base stations 60, 80, and 90.
　図６は、基地局６０の機能的構成を示す図である。図６に示すように、基地局６０は、受信アンテナ６１と、データ受信部６２と、ＲＡＣＨ（Random Access Channel）受信部６３と、ＳＲＳ（Sounding Reference Signal）受信部６４とを備える。また、基地局６０は、送信アンテナ６５と、制御チャネル送信部６６と、データチャネル送信部６７とを備える。また、基地局６０は、データ復調部６８と、データ復号部６９と、受信バッファ７０と、送信バッファ７１とを備える。また、基地局６０は、タイミング検出部７２と、受信品質測定部７３と、スケジューラ部７４と、ＵＬ　ｇｒａｎｔ（UpLink grant）生成部７５と、ＴＡ（Timing Advance）コマンド・ＲＡＲ（Random Access Response）生成部７６とを備える。これら各構成部分は、一方向又は双方向に、信号やデータの入出力が可能なように接続されている。 FIG. 6 is a diagram illustrating a functional configuration of the base station 60. As illustrated in FIG. 6, the base station 60 includes a reception antenna 61, a data reception unit 62, a RACH (Random Access Channel) reception unit 63, and an SRS (Sounding Reference Signal) reception unit 64. The base station 60 includes a transmission antenna 65, a control channel transmission unit 66, and a data channel transmission unit 67. The base station 60 includes a data demodulator 68, a data decoder 69, a reception buffer 70, and a transmission buffer 71. In addition, the base station 60 includes a timing detection unit 72, a reception quality measurement unit 73, a scheduler unit 74, a UL grant (UpLink grant) generation unit 75, a TA (Timing Advance) command and a RAR (Random Access Response) generation. Part 76. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
　データ受信部６２は、受信アンテナ６１を介して、移動局１００から送信される上りリンクのデータを受信する。上りリンクのデータは、例えば移動局１００からＰＵＳＣＨ（Physical Uplink Shared CHannel）を用いて送信される。 The data reception unit 62 receives uplink data transmitted from the mobile station 100 via the reception antenna 61. For example, uplink data is transmitted from the mobile station 100 using PUSCH (PhysicalPhysUplink Shared CHannel).
　ＲＡＣＨ受信部６３は、受信アンテナ６１を介して、移動局１００からＲＡＣＨを用いて送信されるランダムアクセス信号を受信する。ランダムアクセスは、一方の無線通信装置（例えば、移動局）が、データ送信に用いる無線リソースが割り当てられていない状態から、他方の無線通信装置（例えば、基地局）にデータを送信するための手続きである。基地局６０は、ランダムアクセス信号を受信することで、移動局１００との同期を確立する。 The RACH receiving unit 63 receives a random access signal transmitted from the mobile station 100 using the RACH via the receiving antenna 61. Random access is a procedure for transmitting data from one wireless communication device (for example, a mobile station) to the other wireless communication device (for example, a base station) from a state where wireless resources used for data transmission are not allocated. It is. The base station 60 establishes synchronization with the mobile station 100 by receiving the random access signal.
　ＳＲＳ受信部６４は、受信アンテナ６１を介して、移動局１００からＳＲＳを受信する。ＳＲＳは、移動局１００が送信する既知信号であり、基地局６０は、ＳＲＳを受信することで、チャネル品質などを把握する。また、基地局６０は、ＳＲＳを受信することで、移動局１００から基地局６０への送信タイミングを決定する。 The SRS receiving unit 64 receives the SRS from the mobile station 100 via the receiving antenna 61. The SRS is a known signal transmitted by the mobile station 100, and the base station 60 grasps the channel quality and the like by receiving the SRS. Moreover, the base station 60 determines the transmission timing from the mobile station 100 to the base station 60 by receiving SRS.
　データ復調部６８は、データ受信部６２から受信データを入力して、復調処理を行う。復調処理では、例えば、移動局１００から送信されるＤＭ－ＲＳ（DeModulation RS）を参照信号として推定される、ＰＵＳＣＨに対するチャネル推定結果を基に、移動局１００から受信されたデータを復調する。 The data demodulator 68 receives the received data from the data receiver 62 and performs a demodulation process. In the demodulation processing, for example, data received from the mobile station 100 is demodulated based on a channel estimation result for PUSCH estimated using DM-RS (DeModulation RS) transmitted from the mobile station 100 as a reference signal.
　データ復号部６９は、データ復調部６８により復調されたデータを入力して、復号処理を行い、取得したデータを受信バッファ７０に格納する。 The data decoder 69 receives the data demodulated by the data demodulator 68, performs a decoding process, and stores the acquired data in the reception buffer 70.
　タイミング検出部７２は、ＲＡＣＨ受信部６３により受信されたランダムアクセス信号に基づいて、現在の自局の受信タイミングを検出する。また、タイミング検出部７２は、ＳＲＳ受信部６４により受信されたＳＲＳに基づいて、現在の自局の受信タイミングを検出する。また、タイミング検出部７２は、基地局８０，９０のタイミング情報を基地局８０，９０から取得する。例えば、タイミング検出部７２は、基地局８０，９０のＳＲＳ受信部により受信されたＳＲＳに基づいて、基地局８０，９０のタイミング検出部で検出されたタイミング情報を取得する。 The timing detector 72 detects the current reception timing of the local station based on the random access signal received by the RACH receiver 63. The timing detection unit 72 detects the current reception timing of the local station based on the SRS received by the SRS reception unit 64. In addition, the timing detection unit 72 acquires timing information of the base stations 80 and 90 from the base stations 80 and 90. For example, the timing detector 72 acquires timing information detected by the timing detectors of the base stations 80 and 90 based on the SRS received by the SRS receivers of the base stations 80 and 90.
　受信品質測定部７３は、ＳＲＳ受信部６４により受信されるＳＲＳを用いて自局の受信品質を測定する。また、受信品質測定部７３は、基地局８０，９０の受信品質測定部により測定される受信品質を示す情報を、基地局８０，９０から取得する。 The reception quality measurement unit 73 measures the reception quality of the local station using the SRS received by the SRS reception unit 64. Further, the reception quality measuring unit 73 acquires information indicating the reception quality measured by the reception quality measuring unit of the base stations 80 and 90 from the base stations 80 and 90.
　スケジューラ部７４は、基地局６０，８０，９０の受信品質やタイミング情報を基に、リソース割当て等のスケジューリング処理を行う。例えば、スケジューラ部７４は、移動局１００から基地局６０にＳＲＳを送信するためのＳＲＳリソース割当情報を決定する。また、例えば、スケジューラ部７４は、移動局１００から基地局８０，９０にＳＲＳを送信するためのＳＲＳリソース割当情報を取得する。ＳＲＳリソース割当情報は、例えばＳＲＳを送信可能な時間や周波数、ＳＲＳのデータ系列情報を含む。なお、スケジューラ部７４は、基地局６０，８０，９０のＳＲＳリソース割当情報を、基地局６０，８０，９０のＳＲＳが衝突しないように調整してもよい。また、例えば、スケジューラ部７４は、ＣｏＭＰ通信の際に、移動局１００から基地局６０，８０，９０への上りリンクの基準となる送信タイミングを決定する。 The scheduler unit 74 performs scheduling processing such as resource allocation based on the reception quality and timing information of the base stations 60, 80, and 90. For example, the scheduler unit 74 determines SRS resource allocation information for transmitting SRS from the mobile station 100 to the base station 60. For example, the scheduler unit 74 acquires SRS resource allocation information for transmitting SRS from the mobile station 100 to the base stations 80 and 90. The SRS resource allocation information includes, for example, time and frequency at which SRS can be transmitted, and SRS data series information. The scheduler unit 74 may adjust the SRS resource allocation information of the base stations 60, 80, 90 so that the SRSs of the base stations 60, 80, 90 do not collide. Further, for example, the scheduler unit 74 determines a transmission timing serving as an uplink reference from the mobile station 100 to the base stations 60, 80, and 90 during CoMP communication.
　ＵＬ ｇｒａｎｔ生成部７５は、スケジューラ部７４によるスケジューリング情報に基づき、上りリンクのリソースを割り当てるための制御信号を示すＵＬ ｇｒａｎｔを生成する。ＵＬ ｇｒａｎｔは、移動局１００から基地局６０，８０，９０へのＳＲＳリソース割当て情報を含む。また、ＵＬ ｇｒａｎｔは、移動局１００から基地局６０，８０，９０への基準となる送信タイミングを示す情報を含む。第２実施形態では、基準となる送信タイミングを示す情報として、基準となる基地局のセルＩＤを用いる。 The UL grant generation unit 75 generates an UL grant indicating a control signal for allocating uplink resources based on the scheduling information by the scheduler unit 74. The UL grant includes SRS resource allocation information from the mobile station 100 to the base stations 60, 80, and 90. Further, UL grant includes information indicating transmission timing that serves as a reference from the mobile station 100 to the base stations 60, 80, and 90. In the second embodiment, the cell ID of the reference base station is used as the information indicating the reference transmission timing.
　ＴＡコマンド・ＲＡＲ生成部７６は、ランダムアクセス信号の受信結果に基づいて、ランダムアクセス応答ＲＡＲを生成する。ＲＡＲは、ランダムアクセス信号に応じてタイミング検出部７２により検出されたタイミング情報に基づくタイミング調整情報を含む。タイミング調整情報は、例えば、移動局１００から送信される信号が基地局６０で受信されるタイミングが、基地局６０の所定の受信窓内に収まるように、移動局１００の送信タイミングを現在よりも早くするか又は遅くするかを示す。また、ＴＡコマンド・ＲＡＲ生成部７６は、ＳＲＳ受信部６４により受信されたＳＲＳに応じてタイミング検出部７２により検出されたタイミング情報に基づいて、ＴＡコマンドを生成する。ＴＡコマンドは、移動局１００からの送信タイミングについて、現在の送信タイミングよりも次回の送信タイミングをどの程度早くするか又は遅くするかを示す。例えば、基地局６０は、ＳＲＳを受信窓内のどのタイミング位置で受信したか判断し、ＳＲＳの受信タイミング位置が受信窓からはみ出しそうになった場合に窓中心に戻すように、ＴＡコマンドを決定する。 The TA command / RAR generator 76 generates a random access response RAR based on the reception result of the random access signal. The RAR includes timing adjustment information based on the timing information detected by the timing detection unit 72 according to the random access signal. The timing adjustment information includes, for example, the transmission timing of the mobile station 100 from the current time so that the timing at which the signal transmitted from the mobile station 100 is received by the base station 60 is within a predetermined reception window of the base station 60. Indicates whether to make it early or late. Further, the TA command / RAR generator 76 generates a TA command based on the timing information detected by the timing detector 72 according to the SRS received by the SRS receiver 64. The TA command indicates how much the transmission timing from the mobile station 100 should be made earlier or later than the current transmission timing. For example, the base station 60 determines at which timing position in the reception window the SRS is received, and determines the TA command to return to the window center when the reception timing position of the SRS is likely to protrude from the reception window. To do.
　制御チャネル送信部６６は、送信アンテナ６５を介して、制御チャネルを用いて移動局１００に制御情報を送信する。制御チャネルはＰＤＣＣＨ(Physical Downlink Control CHannel)を含む。制御情報はＵＬ ｇｒａｎｔ生成部７５により生成されるＵＬ ｇｒａｎｔを含む。 The control channel transmission unit 66 transmits control information to the mobile station 100 using the control channel via the transmission antenna 65. The control channel includes PDCCH (Physical Downlink Control CHannel). The control information includes a UL custom-character generated by the UL custom-character generating unit 75.
　データチャネル送信部１７は、送信アンテナ６５を介して、データチャネルを用いて移動局１００にデータを送信する。データチャネルはＰＤＳＣＨ(Physical Downlink Shared CHannel)を含む。送信データは、送信バッファ７１に格納されたデータや、ＴＡコマンド・ＲＡＲ生成部７６により生成されるＴＡコマンド・ＲＡＲを含む。 The data channel transmission unit 17 transmits data to the mobile station 100 through the transmission antenna 65 using the data channel. The data channel includes PDSCH (Physical Downlink Shared CHannel). The transmission data includes data stored in the transmission buffer 71 and TA command / RAR generated by the TA command / RAR generation unit 76.
　なお、基地局６０，８０，９０と移動局１００との間で、下りリンクに関してもＣｏＭＰ通信を行っている場合、各基地局６０，８０，９０から移動局１００へデータや制御情報を直接送信することが可能である。この場合、ＳＲＳリソース割当情報やＴＡコマンドは、基地局６０からでなく、基地局８０，９０から移動局１００に送信してもよい。 In addition, when CoMP communication is performed between the base stations 60, 80, 90 and the mobile station 100 regarding the downlink, data and control information are directly transmitted from the base stations 60, 80, 90 to the mobile station 100. Is possible. In this case, the SRS resource allocation information and the TA command may be transmitted from the base stations 80 and 90 to the mobile station 100 instead of from the base station 60.
　図７は、移動局１００の機能的構成を示す図である。図７に示すように、移動局１００は、送信アンテナ１０１と、データ送信部１０２と、ＳＲＳ送信部１０３と、ＲＡＣＨ送信部１０４とを備える。また、移動局１００は、受信アンテナ１０５と、制御チャネル受信部１０６と、データチャネル受信部１０７とを備える。また、移動局１００は、アプリケーション処理部１０９，１１０と、送信バッファ１０８と、受信バッファ１１１とを備える。また、移動局１００は、データ系列生成部１１２と、送信タイミング制御部１１３と、ＵＬ　ｇｒａｎｔ解析部１１４と、上位レイヤ制御情報解析部１１５とを備える。これら各構成部分は、一方向又は双方向に、信号やデータの入出力が可能なように接続されている。 FIG. 7 is a diagram illustrating a functional configuration of the mobile station 100. As illustrated in FIG. 7, the mobile station 100 includes a transmission antenna 101, a data transmission unit 102, an SRS transmission unit 103, and a RACH transmission unit 104. In addition, the mobile station 100 includes a reception antenna 105, a control channel reception unit 106, and a data channel reception unit 107. The mobile station 100 includes application processing units 109 and 110, a transmission buffer 108, and a reception buffer 111. In addition, the mobile station 100 includes a data sequence generation unit 112, a transmission timing control unit 113, a UL grant analysis unit 114, and an upper layer control information analysis unit 115. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
　制御チャネル受信部１０６は、受信アンテナ１０５を介して、制御チャネルを用いて基地局６０から送信される制御情報を受信する。制御チャネルはＰＤＣＣＨ(Physical Downlink Control CHannel)を含む。制御情報はＵＬ ｇｒａｎｔを含む。 The control channel receiving unit 106 receives control information transmitted from the base station 60 using the control channel via the reception antenna 105. The control channel includes PDCCH (Physical Downlink Control CHannel). The control information includes UL grant.
　データチャネル受信部１０７は、受信アンテナ１０５を介して、データチャネルを用いて基地局６０から送信されるデータを受信する。データチャネルはＰＤＳＣＨ(Physical Downlink Shared CHannel)を含む。データチャネル受信部１０７は、制御チャネル１０６により受信される制御情報を用いて、受信データの復調処理や復号処理等を行い、受信バッファ１１０への格納や、上位レイヤ制御情報解析部１１５への入力を行う。 The data channel receiving unit 107 receives data transmitted from the base station 60 using the data channel via the receiving antenna 105. The data channel includes PDSCH (Physical Downlink Shared CHannel). The data channel receiving unit 107 uses the control information received by the control channel 106 to perform demodulation processing, decoding processing, and the like of the received data, and stores in the reception buffer 110 and inputs to the higher layer control information analysis unit 115 I do.
　上位レイヤ制御情報解析部１１５は、データチャネル受信部１０７により受信される上位レイヤ制御情報を取得する。上位レイヤ制御情報は、ＲＡＣＨリソース割当情報や、ＳＲＳリソース割当情報や、ＴＡコマンドを含む。例えば、ＴＡコマンドは、復号された受信データのヘッダ領域に含まれる。 The upper layer control information analyzing unit 115 acquires the upper layer control information received by the data channel receiving unit 107. Upper layer control information includes RACH resource allocation information, SRS resource allocation information, and TA commands. For example, the TA command is included in the header area of the decoded received data.
　ＵＬ　ｇｒａｎｔ解析部１１４は、制御チャネル受信部１０６により受信されるＵＬ　ｇｒａｎｔを解析して情報を取得する。取得される情報は、基準となる送信タイミングに関する情報を含む。 The UL grant analysis unit 114 analyzes the UL grant received by the control channel reception unit 106 and acquires information. The acquired information includes information regarding the transmission timing used as a reference.
　送信タイミング制御部１１３は、上位レイヤ制御情報解析部１１５により取得されるＴＡコマンドや、ＵＬ　ｇｒａｎｔ解析部１１４により取得される基準となる送信タイミングに関する情報に基づいて、ＲＡＣＨを介した送信や、ＳＲＳの送信や、データの送信の送信タイミングを制御する。 The transmission timing control unit 113 performs transmission via the RACH based on the TA command acquired by the upper layer control information analysis unit 115 and information on the transmission timing used as a reference acquired by the UL grant analysis unit 114, and SRS. The transmission timing of data transmission and data transmission is controlled.
　データ系列生成部１１２は、ＲＡＣＨリソース割当情報や、ＳＲＳリソース割当情報に基づいて、ランダムアクセスプリアンブルやＳＲＳに用いられるデータ系列を生成する。 The data sequence generation unit 112 generates a data sequence used for the random access preamble and SRS based on the RACH resource allocation information and the SRS resource allocation information.
　データ送信部１０２は、送信アンテナ１０１を介して、送信バッファ１０８に格納されるデータを基地局６０，８０，９０に送信する。送信データは、例えばＰＵＳＣＨを用いて送信される。 The data transmission unit 102 transmits the data stored in the transmission buffer 108 to the base stations 60, 80, 90 via the transmission antenna 101. The transmission data is transmitted using, for example, PUSCH.
　ＳＲＳ送信部１０３は、送信タイミング制御部１１３に設定される送信タイミングを用いて、基地局６０，８０，９０にＳＲＳを送信する。 The SRS transmission unit 103 transmits the SRS to the base stations 60, 80, 90 using the transmission timing set in the transmission timing control unit 113.
　ＲＡＣＨ送信部１０４は、送信タイミング制御部１１３に設定される送信タイミングを用いて、ＲＡＣＨを用いて信号を送信する。 The RACH transmission unit 104 transmits a signal using the RACH using the transmission timing set in the transmission timing control unit 113.
　アプリケーション処理部１０９は、送信するデータを生成し、送信バッファ１０８に格納される。また、アプリケーション処理部１１０は、受信バッファ１１１に格納された受信データを取得して処理する。 The application processing unit 109 generates data to be transmitted and stores it in the transmission buffer 108. In addition, the application processing unit 110 acquires and processes the reception data stored in the reception buffer 111.
　図８は、基地局６０のハードウェア構成を示す図である。図８に示すように、基地局６０は、ハードウェアの構成要素として、例えば、ＤＳＰ６０Ａと、ＦＰＧＡ６０Ｂと、メモリ６０Ｃと、アンテナＡ１を備えるＲＦ回路６０Ｄと、ネットワークＩＦ６０Ｅとを有する。ＤＳＰ６０Ａと、ＦＰＧＡ６０Ｂとは、スイッチ等のネットワークＩＦ６０Ｅを介して各種信号やデータの入出力が可能なように接続されている。メモリ６０Ｃは、例えば、ＳＤＲＡＭ等のＲＡＭ、ＲＯＭ、及びフラッシュメモリを含み、プログラムや制御情報やデータを格納する。データ復調部６８、データ復号部６９、タイミング検出部７２、受信品質測定部７３、スケジューラ部７４、ＵＬ　ｇｒａｎｔ生成部７５、及びＴＡコマンド・ＲＡＲ生成部７６は、例えばＤＳＰ６０Ａ、ＦＰＧＡ６０Ｂ等の集積回路により実現される。データ受信部６２、ＲＡＣＨ受信部６３、ＳＲＳ受信部６４、制御チャネル送信部６６及びデータチャネル送信部６７は、例えばＲＦ回路６０Ｄにより実現される。受信バッファ７０および送信バッファ７１は、例えばメモリ６０Ｃにより実現される。以上、基地局６０のハードウェア構成を説明したが、他の基地局８０，９０のハードウェア構成は、基地局６０と同様であるので、その詳細な説明は省略する。 FIG. 8 is a diagram illustrating a hardware configuration of the base station 60. As illustrated in FIG. 8, the base station 60 includes, as hardware components, for example, a DSP 60A, an FPGA 60B, a memory 60C, an RF circuit 60D including an antenna A1, and a network IF 60E. The DSP 60A and the FPGA 60B are connected so that various signals and data can be input / output via a network IF 60E such as a switch. The memory 60C includes, for example, a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data. The data demodulating unit 68, the data decoding unit 69, the timing detecting unit 72, the reception quality measuring unit 73, the scheduler unit 74, the UL grant generating unit 75, and the TA command / RAR generating unit 76 are, for example, integrated circuits such as a DSP 60A and FPGA 60B. Realized. The data receiving unit 62, the RACH receiving unit 63, the SRS receiving unit 64, the control channel transmitting unit 66, and the data channel transmitting unit 67 are realized by, for example, the RF circuit 60D. The reception buffer 70 and the transmission buffer 71 are realized by the memory 60C, for example. Although the hardware configuration of the base station 60 has been described above, the hardware configuration of the other base stations 80 and 90 is the same as that of the base station 60, and thus detailed description thereof is omitted.
　また、移動局１００は、例えば携帯電話機等の携帯端末によって実現される。図９は、移動局１００のハードウェア構成を示す図である。図９に示すように、移動局１００は、ハードウェアの構成要素として、例えば、ＣＰＵ１００Ａと、メモリ１００Ｂと、アンテナＡ２を備えるＲＦ回路１００Ｃと、ＬＣＤ（Liquid　Crystal　Display）等の表示装置１００Ｄとを有する。メモリ１００Ｂは、例えば、ＳＤＲＡＭ等のＲＡＭ、ＲＯＭ、及びフラッシュメモリを含み、プログラムや制御情報やデータを格納する。データ送信部１０２、ＳＲＳ送信部１０３、ＲＡＣＨ送信部１０４、制御チャネル受信部１０６、及びデータチャネル受信部１０７は、例えばＲＦ回路１００Ｃにより実現される。また、アプリケーション処理部１０９，１１０、データ系列生成部１１２、送信タイミング制御部１１３、ＵＬ　ｇｒａｎｔ解析部１１４、及び上位レイヤ制御情報解析部１１５は、例えばＣＰＵ１００Ａ等の集積回路により実現される。送信バッファ１０８及び受信バッファ１１１は、例えばメモリ１００Ｂにより実現される。 Further, the mobile station 100 is realized by a mobile terminal such as a mobile phone. FIG. 9 is a diagram illustrating a hardware configuration of the mobile station 100. As shown in FIG. 9, the mobile station 100 includes, as hardware components, for example, a CPU 100A, a memory 100B, an RF circuit 100C including an antenna A2, and a display device 100D such as an LCD (Liquid Crystal Display). Have. The memory 100B includes, for example, a RAM such as an SDRAM, a ROM, and a flash memory, and stores programs, control information, and data. The data transmission unit 102, SRS transmission unit 103, RACH transmission unit 104, control channel reception unit 106, and data channel reception unit 107 are realized by, for example, the RF circuit 100C. The application processing units 109 and 110, the data series generation unit 112, the transmission timing control unit 113, the UL grant analysis unit 114, and the higher layer control information analysis unit 115 are realized by an integrated circuit such as the CPU 100A, for example. The transmission buffer 108 and the reception buffer 111 are realized by the memory 100B, for example.
　次に、第２実施形態の無線通信システム５０の動作を説明する。図１０、１１は、無線通信システム５０の動作を説明するためのシーケンス図である。 Next, the operation of the wireless communication system 50 according to the second embodiment will be described. 10 and 11 are sequence diagrams for explaining the operation of the wireless communication system 50.
　図１０に示すように、移動局１００は、基地局６０に対して初期同期用のランダムアクセス信号の送信を行う（Ｓ１１）。例えば、移動局１００は、ＢＣＨ（Broadcast CHannel）を用いて送信されるシステム情報に基づいて、データ系列生成部１１２により複数通りの信号系列の中からランダムに選択した信号系列をランダムアクセスプリアンブルとして、基地局６０に送信する。ＲＡＣＨを介して送信される信号は、ＣＰ長が長く設定されており、受信タイミングずれの許容範囲が比較的大きいので、初期のタイミング制御が行われていない段階でも受信をすることが可能となっている。基地局６０は、ランダムアクセス信号を受信することにより、現在の自局の受信タイミングを把握できる。 As shown in FIG. 10, the mobile station 100 transmits a random access signal for initial synchronization to the base station 60 (S11). For example, the mobile station 100 uses a signal sequence randomly selected from a plurality of signal sequences by the data sequence generation unit 112 based on system information transmitted using BCH (Broadcast 用 い CHannel) as a random access preamble. Transmit to the base station 60. A signal transmitted via the RACH is set to have a long CP length, and the allowable range of the reception timing deviation is relatively large. Therefore, it is possible to receive even when the initial timing control is not performed. ing. The base station 60 can grasp the current reception timing of its own station by receiving the random access signal.
　基地局６０は、受信したランダムアクセス信号への応答として、ＲＡＲを送信する（Ｓ１２）。ＲＡＲは、上りリンクの送信タイミングのタイミング調整情報を含む。移動局１００は、このタイミング調整情報に基づいて次回の送信タイミングを決定する。これにより、基地局６０と移動局１００との間で同期が確立される。 The base station 60 transmits RAR as a response to the received random access signal (S12). RAR includes timing adjustment information of uplink transmission timing. The mobile station 100 determines the next transmission timing based on this timing adjustment information. As a result, synchronization is established between the base station 60 and the mobile station 100.
　基地局６０は、移動局１００にＣｏＭＰ通信を開始するメッセージを送信する（Ｓ１３）。このメッセージは、例えば協調基地局８０，９０のセルＩＤ割当情報を含む。また、基地局６０は、ＣｏＭＰ通信に必要な情報を基地局８０，９０に通知する。なお、協調基地局を選定する処理を移動局１００主導で行ってもよい。 The base station 60 transmits a message for starting CoMP communication to the mobile station 100 (S13). This message includes cell ID allocation information of the cooperative base stations 80 and 90, for example. The base station 60 notifies the base stations 80 and 90 of information necessary for CoMP communication. Note that the process of selecting a cooperative base station may be performed by the mobile station 100.
　以下、移動局１００は、協調基地局８０，９０との間で同期を確立する（Ｓ１４～Ｓ１７）。移動局１００は、基地局８０に対して、初期同期用のランダムアクセス送信を行う（Ｓ１４）。ＲＡＣＨリソース割当情報は、ＢＣＨやＰＵＣＣＨを用いて基地局８０は、受信したランダムアクセスプリアンブルへの応答として、上りリンクの送信タイミング調整情報を含むＲＡＲを送信する（Ｓ１５）。また、移動局１００は、基地局９０に対して、初期同期用のランダムアクセス送信を行う（Ｓ１６）。基地局９０は、受信したランダムアクセスプリアンブルへの応答として、基地局９０への上りリンクの送信タイミング調整情報を含むＲＡＲを送信する（Ｓ１７）。これにより、移動局１００と、各基地局６０，８０，９０との間で、送信タイミングの初期同期が行われ、各基地局６０，８０，９０への送信タイミングの初期値が格納される。 Hereinafter, the mobile station 100 establishes synchronization with the coordinated base stations 80 and 90 (S14 to S17). The mobile station 100 performs random access transmission for initial synchronization to the base station 80 (S14). The RACH resource allocation information uses BCH or PUCCH, and the base station 80 transmits an RAR including uplink transmission timing adjustment information as a response to the received random access preamble (S15). In addition, the mobile station 100 performs random access transmission for initial synchronization to the base station 90 (S16). The base station 90 transmits an RAR including uplink transmission timing adjustment information to the base station 90 as a response to the received random access preamble (S17). Thereby, initial synchronization of transmission timing is performed between the mobile station 100 and each base station 60, 80, 90, and the initial value of the transmission timing to each base station 60, 80, 90 is stored.
　基地局８０は、ＳＲＳリソース割当情報を基地局６０に通知する（Ｓ１８）。また、基地局９０は、ＳＲＳリソース割当情報を基地局６０に通知する（Ｓ１９）。基地局６０は、基地局６０，８０，９０のＳＲＳリソース割当情報を移動局１００に送信する（Ｓ２０）。なお、基地局６０，８０，９０が下りリンクのＣｏＭＰ通信を行う場合、基地局６０，８０，９０から移動局１００に各ＳＲＳリソース割当情報を直接送信してもよい。 The base station 80 notifies the SRS resource allocation information to the base station 60 (S18). Further, the base station 90 notifies the SRS resource allocation information to the base station 60 (S19). The base station 60 transmits the SRS resource allocation information of the base stations 60, 80, 90 to the mobile station 100 (S20). In addition, when the base stations 60, 80, 90 perform downlink CoMP communication, the SRS resource allocation information may be directly transmitted from the base stations 60, 80, 90 to the mobile station 100.
　以下、基地局６０，８０，９０は、順に上りリンクの送信タイミングの更新処理を周期的に繰り返す（Ｓ２１～Ｓ２８）。なお、この上りリンクの送信タイミングの更新処理は、データチャネルを用いた上位レイヤ制御情報の伝送周期で行われる。上位レイヤ制御情報は、例えば、８０［ｍｓ］、１６０［ｍｓ］または３２０［ｍｓ］といった周期で伝送される。 Hereinafter, the base stations 60, 80, and 90 periodically repeat uplink transmission timing update processing in order (S21 to S28). The uplink transmission timing update process is performed in the transmission cycle of the upper layer control information using the data channel. The upper layer control information is transmitted at a period of 80 [ms], 160 [ms], or 320 [ms], for example.
　移動局１００は、基地局６０にＳＲＳを送信し（Ｓ２１）、基地局６０は、ＴＡコマンドを生成して移動局１００に送信する（Ｓ２２）。また、移動局１００は、基地局８０にＳＲＳを送信し（Ｓ２３）、基地局８０は、ＴＡコマンドを生成して基地局６０に通知し（Ｓ２４）、基地局６０は通知されたＴＡコマンドを移動局１００に送信する（Ｓ２５）。また、移動局１００は、基地局９０にＳＲＳを送信し（Ｓ２６）、ＴＡコマンドを生成して基地局６０に通知し（Ｓ２７）、基地局６０は通知されたＴＡコマンドを移動局１００に送信する（Ｓ２８）。移動局１００は、受信したＴＡコマンドに応じて、格納されている各基地局６０，８０，９０への送信タイミングを更新する。移動局１００は、更新された送信タイミングを用いて、基地局６０，８０，９０への次回の送信を行う。なお、基地局６０，８０，９０が下りリンクのＣｏＭＰ通信を行う場合、基地局６０，８０，９０から移動局１００に各ＴＡコマンドを直接送信してもよい。 The mobile station 100 transmits an SRS to the base station 60 (S21), and the base station 60 generates a TA command and transmits it to the mobile station 100 (S22). Further, the mobile station 100 transmits an SRS to the base station 80 (S23), the base station 80 generates a TA command and notifies the base station 60 (S24), and the base station 60 transmits the notified TA command. It transmits to the mobile station 100 (S25). Also, the mobile station 100 transmits an SRS to the base station 90 (S26), generates a TA command and notifies the base station 60 (S27), and the base station 60 transmits the notified TA command to the mobile station 100. (S28). The mobile station 100 updates the stored transmission timing to each of the base stations 60, 80, 90 in accordance with the received TA command. The mobile station 100 performs the next transmission to the base stations 60, 80, and 90 using the updated transmission timing. When the base stations 60, 80, 90 perform downlink CoMP communication, the TA commands may be directly transmitted from the base stations 60, 80, 90 to the mobile station 100.
　次に、図１１に示すように、上りリンクのデータ送信を開始する場合、移動局１００は、基地局６０，８０，９０に対してそれぞれＳＲＳを送信する（Ｓ２９～Ｓ３１）。基地局６０，８０，９０は連携して、受信品質を測定・取得する（Ｓ３２）。例えば、基地局６０，８０，９０は、受信したＳＲＳを参照信号としてそれぞれ、受信品質を測定する。基地局６０は、基地局８０，９０の受信品質に関する情報と、タイミング情報とを、基地局８０，９０から取得する。 Next, as shown in FIG. 11, when starting uplink data transmission, the mobile station 100 transmits SRSs to the base stations 60, 80, and 90, respectively (S29 to S31). The base stations 60, 80, 90 cooperate to measure and acquire the reception quality (S32). For example, the base stations 60, 80, and 90 measure the reception quality using the received SRS as a reference signal. The base station 60 acquires information on the reception quality of the base stations 80 and 90 and timing information from the base stations 80 and 90.
　基地局６０，８０，９０は連携して、移動局１００からデータを送信する際の基準となる送信タイミングに関する情報を決定する（Ｓ３３）。例えば、基地局６０は、基地局６０，８０，９０の受信品質に関する情報と、タイミング情報とに基づいて、送信タイミングの基準となる基地局を決定する（Ｓ３３）。これにより、基準となる送信タイミングが、基地局６０，８０，９０間で調整されて適切に決定される。 The base stations 60, 80, and 90 cooperate to determine information regarding transmission timing that is a reference when data is transmitted from the mobile station 100 (S33). For example, the base station 60 determines a base station serving as a reference for transmission timing based on the information regarding the reception quality of the base stations 60, 80, 90 and the timing information (S33). Thereby, the reference transmission timing is adjusted between the base stations 60, 80, and 90 and appropriately determined.
　基地局６０は、基準となる送信タイミングに関する情報を、移動局１００に送信する（Ｓ３４）。例えば、基地局６０は、基準となる基地局のセルＩＤを含むＵＬ ｇｒａｎｔを生成し、生成したＵＬ ｇｒａｎｔを移動局１００に送信する。なお、制御チャネルを用いたＵＬ　ｇｒａｎｔの伝送は、上位レイヤ制御情報の伝送より短い周期で行われる。例えば、ＵＬ　ｇｒａｎｔは、１［ｍｓ］といった周期で伝送される。このように比較的短い周期で送信タイミングが制御されるので、伝搬環境の変動等に適切に追従した送信タイミングで上りリンクの送信を行うことができる。 The base station 60 transmits information related to the reference transmission timing to the mobile station 100 (S34). For example, the base station 60 generates a UL custom-character including the cell ID of the base station serving as a reference, and transmits the generated UL custom-character to the mobile station 100. Note that UL grant transmission using the control channel is performed in a shorter cycle than transmission of higher layer control information. For example, UL grant is transmitted at a cycle of 1 [ms]. Since the transmission timing is controlled in such a relatively short cycle, uplink transmission can be performed at a transmission timing that appropriately follows changes in the propagation environment.
　移動局１００は、受信した基準となる送信タイミングで、基地局６０，８０，９０にデータを送信する（Ｓ３５）。これにより、基地局６０，８０，９０間で調整された適切な送信タイミングでデータが送信される。移動局１００から送信されたデータは、基地局６０，８０，９０でそれぞれ受信される。 The mobile station 100 transmits data to the base stations 60, 80, 90 at the transmission timing that is the received reference (S35). Thereby, data is transmitted at an appropriate transmission timing adjusted between the base stations 60, 80 and 90. Data transmitted from the mobile station 100 is received by the base stations 60, 80, and 90, respectively.
　基地局６０，８０，９０は連携して、基地局６０，８０，９０で受信された信号を合成してデータを取得する（Ｓ３６）。例えば、基地局６０は、基地局８０，９０で受信された信号を取得し、基地局６０，８０，９０で受信された信号を合成してデータを取得する。基地局６０，８０，９０間で調整された送信タイミングでデータが送信されるので、合成後の受信信号においてシンボル間干渉の影響が低減され、受信特性が向上される。 The base stations 60, 80, 90 cooperate to synthesize signals received at the base stations 60, 80, 90 to acquire data (S36). For example, the base station 60 acquires signals received by the base stations 80 and 90, and combines the signals received by the base stations 60, 80, and 90 to acquire data. Since data is transmitted at the transmission timing adjusted between the base stations 60, 80, 90, the influence of intersymbol interference is reduced in the combined received signal, and reception characteristics are improved.
　上記の動作について、図１２，図１３の例を用いて説明する。図１２は、基地局６０，８０，９０での受信タイミングを説明するための図である。図１２の例では、ＯＦＤＭ信号が受信され、ＦＦＴ窓を用いて処理される。図１２（Ａ）（Ｂ）（Ｃ）はそれぞれ、横方向は時間を示し、上から順に基地局６０，８０，９０におけるＯＦＤＭシンボルの受信タイミングを示す。 The above operation will be described with reference to the examples of FIGS. FIG. 12 is a diagram for explaining reception timings at the base stations 60, 80, 90. In the example of FIG. 12, an OFDM signal is received and processed using an FFT window. In each of FIGS. 12A, 12B, and 12C, the horizontal direction indicates time, and the OFDM symbol reception timing in the base stations 60, 80, and 90 in order from the top.
　図１２（Ａ）の状態では、基地局６０の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように、送信タイミングが決定されている。このとき、基地局８０，９０では、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まらず、領域Ｃ，Ｄでシンボル間干渉が生じる。 In the state of FIG. 12 (A), the transmission timing is determined so that the received OFDM symbol of the base station 60 fits in the received FFT window. At this time, in the base stations 80 and 90, the received OFDM symbols do not fit in the received FFT window, and intersymbol interference occurs in the regions C and D.
　図１２（Ｂ）の状態では、送信タイミングが図１２（Ａ）の状態より早められ、基地局８０の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように、送信タイミングが決定されている。このとき、基地局６０，９０では、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まらず、領域Ｅ，Ｆでシンボル間干渉が生じる。 In the state of FIG. 12B, the transmission timing is determined so that the transmission timing is advanced from the state of FIG. 12A, and the received OFDM symbol of the base station 80 fits in the reception FFT window. At this time, in the base stations 60 and 90, the received OFDM symbols do not fit in the received FFT window, and intersymbol interference occurs in the regions E and F.
　図１２（Ｃ）の状態では、送信タイミングが図１２（Ｂ）の状態より早められ、基地局９０の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように、送信タイミングが決定されている。このとき、基地局６０では、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まらず、領域Ｇでシンボル間干渉が生じる。 In the state of FIG. 12C, the transmission timing is determined so that the transmission timing is earlier than the state of FIG. 12B, and the received OFDM symbol of the base station 90 fits in the reception FFT window. At this time, in the base station 60, the received OFDM symbol does not fit in the received FFT window, and intersymbol interference occurs in the region G.
　図１３は、基地局６０，８０，９０での受信特性を説明するための図である。図１３の例では、受信品質としてＳＩＮＲが用いられる。図１３において、縦軸はＳＩＮＲを示し、横軸は受信のタイミングを示す。タイミングは、有効ＯＦＤＭシンボル長を１として、基地局６０で受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている状態のタイミングＴ３を０とした場合の相対値とする。基地局８０は、タイミングＴ４＝０．１８で、基地局８０での受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている状態となる。基地局９０は、タイミングＴ５＝０．２で、基地局９０での受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている状態となる。 FIG. 13 is a diagram for explaining the reception characteristics at the base stations 60, 80, 90. In the example of FIG. 13, SINR is used as the reception quality. In FIG. 13, the vertical axis represents SINR, and the horizontal axis represents reception timing. The timing is a relative value when the effective OFDM symbol length is 1, and the timing T3 in the state where the received OFDM symbol is within the received FFT window at the base station 60 is 0. The base station 80 enters a state where the received OFDM symbol at the base station 80 is within the received FFT window at timing T4 = 0.18. The base station 90 enters a state in which the received OFDM symbol at the base station 90 is within the received FFT window at timing T5 = 0.2.
　図１３は、送信タイミングを状態Ｐから状態Ｒまで変化させた場合の、基地局６０で受信する信号のＳＩＮＲ（図１３にて「□」で示す）、基地局８０で受信する信号のＳＩＮＲ（図１３にて「△」で示す）、基地局９０で受信する信号のＳＩＮＲ（図１３にて「×」で示す）、および合成後の受信信号のＳＩＮＲ（図１３にて「○」で示す）を示している。なお、各基地局６０，８０，９０のＳＩＮＲは、基地局６０，８０，９０毎のタイミング制御により、受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まるように制御されている状態でそれぞれ測定される。 FIG. 13 illustrates the SINR (indicated by “□” in FIG. 13) of the signal received by the base station 60 and the SINR of the signal received by the base station 80 when the transmission timing is changed from the state P to the state R. 13, the SINR of the signal received by the base station 90 (indicated by “X” in FIG. 13), and the SINR of the combined received signal (indicated by “◯” in FIG. 13). ). The SINR of each of the base stations 60, 80, 90 is measured in a state where the received OFDM symbols are controlled to be within the reception FFT window by the timing control for each of the base stations 60, 80, 90.
　図１３に示すように、基地局６０のＳＩＮＲは、タイミングＴ３の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている図１２（Ａ）の状態で値Ｒ４となり、図１２（Ａ）の状態から図１２（Ｃ）の状態に変化するにつれて、シンボル間干渉の増大によりＳＩＮＲが低下している。また、基地局８０のＳＩＮＲは、タイミングＴ４の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている図１２（Ｂ）の状態で最大値Ｒ５（＜Ｒ４）となっている。また、基地局９０のＳＩＮＲは、タイミングＴ５の受信ＯＦＤＭシンボルが受信ＦＦＴ窓に収まっている図１２（Ｃ）の状態で値Ｒ６（＜Ｒ５）となっている。このとき、合成後の受信信号のＳＩＮＲは、タイミングＴ４の図１２（Ｂ）の状態で最大値Ｒ７となっている。 As shown in FIG. 13, the SINR of the base station 60 becomes the value R4 in the state of FIG. 12A where the received OFDM symbol at the timing T3 is within the received FFT window, and from the state of FIG. As the state changes to (C), the SINR decreases due to the increase in intersymbol interference. The SINR of the base station 80 is the maximum value R5 (<R4) in the state of FIG. 12B in which the received OFDM symbol at the timing T4 is within the received FFT window. The SINR of the base station 90 is a value R6 (<R5) in the state of FIG. 12C in which the received OFDM symbol at timing T5 is within the received FFT window. At this time, the SINR of the combined received signal is the maximum value R7 in the state of FIG. 12B at timing T4.
　このとき、合成後の受信信号の受信品質を最も高くする送信タイミングとして、基地局６０，８０，９０のうち基地局８０が、基準となる基地局として決定される。この場合、受信品質と、受信タイミングの分布とを考慮すると、受信品質が最も高い基地局６０のタイミングに合わせるより、受信タイミングが密に分布する基地局８０，９０のタイミングに近づける方が、シンボル間干渉の影響を低減する効果が大きい。 At this time, the base station 80 of the base stations 60, 80, 90 is determined as a reference base station as the transmission timing that maximizes the reception quality of the combined received signal. In this case, considering the reception quality and the distribution of the reception timing, it is more possible to make the symbol closer to the timing of the base stations 80 and 90 where the reception timing is densely distributed than to match the timing of the base station 60 having the highest reception quality. The effect of reducing the influence of interfering interference is great.
　そして、基準となる基地局として、基地局８０のセルＩＤが移動局１００に送信され、移動局１００から、基準となる送信タイミングとして、基地局８０への予め定められた送信タイミングで、移動局１００から基地局６０，８０，９０へデータが送信される。これにより、基地局６０，８０，９０で受信された信号を合成してデータを取得する際に、合成後の受信信号においてシンボル間干渉の影響が低減され、受信特性が向上される。 Then, the cell ID of the base station 80 is transmitted as the reference base station to the mobile station 100, and the mobile station 100 transmits the reference transmission timing to the base station 80 at a predetermined transmission timing as the reference transmission timing. Data is transmitted from 100 to the base stations 60, 80, 90. Thereby, when data is acquired by combining the signals received by the base stations 60, 80, 90, the influence of intersymbol interference is reduced in the combined received signal, and reception characteristics are improved.
　以上により、第２実施形態によれば、上りリンクのＣｏＭＰ通信を行う無線通信システム５０において、受信特性を向上させることができる。 As described above, according to the second embodiment, reception characteristics can be improved in the radio communication system 50 that performs uplink CoMP communication.
　なお、他の実施形態として、基準となる送信タイミングを決定する際に、受信品質を受信タイミングの分布に応じた所定値で補正した値を指標値とし、この指標値を比較して、基準となる送信タイミングを決定してもよい。例えば、受信タイミングの中央値または平均値に基づいた相対値に応じた係数を受信品質に乗算したり、受信タイミングの中央値または平均値に基づいた相対値に応じたオフセット値を受信品質に加算したりしてもよい。また、例えば、受信タイミングの中央値または平均値から近い順番に応じた係数を受信品質に乗算したり、受信タイミングの中央値または平均値から近い順番に応じたオフセット値を受信品質に加算したりしてもよい。また、例えば、受信タイミングの中央値または平均値に最も近い基地局を選択したり、最も近い基地局に所定係数を乗算したり所定オフセット値を加算したりしてもよい。
［第３実施形態］
　図１４は、第３実施形態に係る無線通信システム２００の構成を示す図である。図１４に示すように、無線通信システム２００は、移動局１００と、セルを形成する基地局と、を含む。基地局は、複数のＲＲＨ（Remote Radio Head）２３０Ａ～２３０Ｃと、ＢＢＵ（BaseBand Unit）２２０とを有する。ＲＲＨ２３０Ａ～２３０Ｃはそれぞれ、アンテナ（ポイント）を有して離れた地点に配設され、カバーエリアＥ２１，２２，２３を形成している。基地局のセルは、カバーエリアＥ２１，２２，２３により形成される。ＢＢＵ２２０は、ＲＲＨ２３０Ａ～２３０Ｃと離れた地点に配設され、ＲＲＨ２３０Ａ～２３０Ｃと有線接続により接続される。移動局１００は、ＲＲＨ２３０ＡのカバーエリアＥ２１に在圏している。ＲＲＨ２３０Ａ～２３０Ｃは、第１の無線通信装置の一例に相当し、互いに通信を行うと共に、移動局１００に対してＣｏＭＰ通信を行う。ＲＲＨ２３０ＡのカバーエリアＥ２１をサービングセルとし、ＲＲＨ２３０Ｂ，２３０ＣのカバーエリアＥ２２，Ｅ２３を協調セルとする。ＲＲＨ２３０Ａ～２３０Ｃは、上りリンクのＣｏＭＰ通信を行っており、移動局１００が送信するデータをＲＲＨ２３０Ａ～２３０Ｃで協調して受信し合成する処理を行う。移動局１００の構成および動作は、第２実施形態の移動局１００と同じであるので、同じ符号を付して説明を省略する。 As another embodiment, when determining the reference transmission timing, a value obtained by correcting the reception quality with a predetermined value corresponding to the distribution of the reception timing is used as an index value. The transmission timing may be determined. For example, the reception quality is multiplied by a coefficient corresponding to the relative value based on the median or average value of the reception timing, or an offset value corresponding to the relative value based on the median or average value of the reception timing is added to the reception quality. You may do it. Also, for example, the reception quality is multiplied by a coefficient according to the order close to the median or average value of the reception timing, or an offset value according to the order close to the median or average value of the reception timing is added to the reception quality. May be. Further, for example, the base station closest to the median or average value of the reception timing may be selected, or the nearest base station may be multiplied by a predetermined coefficient or a predetermined offset value may be added.
[Third Embodiment]
FIG. 14 is a diagram illustrating a configuration of a wireless communication system 200 according to the third embodiment. As illustrated in FIG. 14, the wireless communication system 200 includes a mobile station 100 and base stations that form a cell. The base station includes a plurality of RRHs (Remote Radio Heads) 230A to 230C and a BBU (BaseBand Unit) 220. Each of the RRHs 230A to 230C has an antenna (point) and is arranged at a distant point to form cover areas E21, 22 and 23. The cell of the base station is formed by the cover areas E21, 22 and 23. The BBU 220 is disposed at a point distant from the RRHs 230A to 230C, and is connected to the RRHs 230A to 230C by wired connection. The mobile station 100 is located in the cover area E21 of the RRH 230A. The RRHs 230A to 230C correspond to an example of a first wireless communication device, and perform communication with each other and CoMP communication with the mobile station 100. Cover area E21 of RRH 230A is used as a serving cell, and cover areas E22 and E23 of RRH 230B and 230C are used as cooperative cells. The RRHs 230A to 230C perform uplink CoMP communication, and perform processing of receiving and combining the data transmitted by the mobile station 100 in cooperation with the RRHs 230A to 230C. Since the configuration and operation of the mobile station 100 are the same as those of the mobile station 100 of the second embodiment, the same reference numerals are given and description thereof is omitted.
　図１５は基地局２１０のＲＲＨ２３０Ａ～２３０ＣとＢＢＵ２２０との機能的構成を示す図である。図１５に示すように、基地局２１０のＲＲＨ２３０Ａは、受信アンテナ２３１Ａと、送信アンテナ２３２Ａと、無線部２３３Ａとを備える。無線部２３３Ａは、データ受信部２３４Ａと、ＲＡＣＨ受信部２３５Ａと、ＳＲＳ受信部２３６Ａと、制御チャネル送信部２３７Ａと、データチャネル送信部２３８Ａとを備える。また、ＢＢＵ２２０は、データ復調部２４０と、データ復号部２４１と、タイミング検出部２４３と、受信バッファ２４２と、受信品質測定部２４４と、スケジューラ部２４５と、ＵＬ　ｇｒａｎｔ生成部２４６と、ＴＡコマンド・ＲＡＲ生成部２４７と、送信バッファ２４８とを備える。ＲＲＨ２３０Ａ及びＢＢＵ２２０の各構成部分の詳細は、第２実施形態の基地局６０の各構成部分と同様である。 FIG. 15 is a diagram showing a functional configuration of the RRHs 230A to 230C and the BBU 220 of the base station 210. As illustrated in FIG. 15, the RRH 230A of the base station 210 includes a reception antenna 231A, a transmission antenna 232A, and a radio unit 233A. The radio unit 233A includes a data receiver 234A, a RACH receiver 235A, an SRS receiver 236A, a control channel transmitter 237A, and a data channel transmitter 238A. The BBU 220 includes a data demodulator 240, a data decoder 241, a timing detector 243, a reception buffer 242, a reception quality measurement unit 244, a scheduler unit 245, a UL grant generation unit 246, a TA command A RAR generator 247 and a transmission buffer 248 are provided. Details of the components of the RRH 230A and the BBU 220 are the same as those of the components of the base station 60 of the second embodiment.
　ＲＲＨ２３０Ｂは、受信アンテナ２３１Ｂと、送信アンテナ２３２Ｂと、無線部２３３Ｂとを備える。無線部２３３Ｂは、データ受信部２３４Ｂと、ＲＡＣＨ受信部２３５Ｂと、ＳＲＳ受信部２３６Ｂと、制御チャネル送信部２３７Ｂと、データチャネル送信部２３８Ａとを備える。ＲＲＨ２３０Ｂの各構成部分の詳細は、ＲＲＨ２３０Ａの各構成部分と同様である。 The RRH 230B includes a reception antenna 231B, a transmission antenna 232B, and a radio unit 233B. The radio unit 233B includes a data reception unit 234B, a RACH reception unit 235B, an SRS reception unit 236B, a control channel transmission unit 237B, and a data channel transmission unit 238A. Details of each component of the RRH 230B are the same as each component of the RRH 230A.
　ＲＲＨ２３０Ｃは、受信アンテナ２３１Ｃと、送信アンテナ２３２Ｃと、無線部２３３Ｃとを備える。無線部２３３Ｃは、データ受信部２３４Ｃと、ＲＡＣＨ受信部２３５Ｃと、ＳＲＳ受信部２３６Ｃと、制御チャネル送信部２３７Ｃと、データチャネル送信部２３８Ｃとを備える。ＲＲＨ２３０Ｃの各構成部分の詳細は、ＲＲＨ２３０Ａの各構成部分と同様である。 The RRH 230C includes a reception antenna 231C, a transmission antenna 232C, and a radio unit 233C. The radio unit 233C includes a data reception unit 234C, a RACH reception unit 235C, an SRS reception unit 236C, a control channel transmission unit 237C, and a data channel transmission unit 238C. Details of each component of the RRH 230C are the same as each component of the RRH 230A.
　次に、無線通信システム２００の動作について説明する。無線通信システム２００の動作は、基本的に、第２実施形態の基地局６０，８０，９０の送受信動作を、ＲＲＨ２３０Ａ～２３０Ｃの動作としたものであり、基地局６０，８０，９０の制御動作を、ＢＢＵ２２０の動作としたものである。ただし、第２実施形態では、基地局６０を主導で、基地局８０，９０から情報を取得して協調処理（Ｓ３２、Ｓ３３，Ｓ３６）を行うに対し、第３実施形態では、ＢＢＵ２２０で情報を集約して協調処理を行う。 Next, the operation of the wireless communication system 200 will be described. The operation of the wireless communication system 200 is basically the transmission / reception operation of the base stations 60, 80, 90 of the second embodiment as the operation of the RRHs 230A-230C. The control operation of the base stations 60, 80, 90 Is the operation of the BBU 220. However, in the second embodiment, the base station 60 takes the initiative to acquire information from the base stations 80 and 90 and perform cooperative processing (S32, S33, S36), whereas in the third embodiment, the BBU 220 performs information processing. Aggregate and perform cooperative processing.
　無線通信システム２００のタイミング制御の動作では、第２実施形態の図１３の説明と同様にタイミング制御が実行される。例えば、上りリンクのＣｏＭＰ通信を行うＲＲＨ２３０Ａ～２３０Ｃについて、合成後の受信信号の受信品質を最も高くする送信タイミングとして、基準となる送信タイミングが決定される。 In the timing control operation of the wireless communication system 200, timing control is executed in the same manner as in the description of FIG. 13 of the second embodiment. For example, for RRHs 230A to 230C that perform uplink CoMP communication, a reference transmission timing is determined as the transmission timing that maximizes the reception quality of the combined received signal.
　第３実施形態によれば、第２実施形態と同様に、上りリンクのＣｏＭＰ通信を行う無線通信システム２００において、受信特性を向上させることができる。
［第４実施形態］
　図１６は、第４実施形態に係る無線通信システム３００の構成を示す図である。無線通信システム３００では、第１の無線通信装置の一例として、基地局３１０、３２０、３３０と、ＲＲＨ３４０Ａ～３４０Ｌとが混在し、これらの少なくとも一部が協調通信を行う。 According to the third embodiment, similarly to the second embodiment, reception characteristics can be improved in the wireless communication system 200 that performs uplink CoMP communication.
[Fourth Embodiment]
FIG. 16 is a diagram illustrating a configuration of a wireless communication system 300 according to the fourth embodiment. In the wireless communication system 300, base stations 310, 320, and 330 and RRHs 340A to 340L are mixed as an example of a first wireless communication apparatus, and at least a part of these perform cooperative communication.
　図１６に示すように、無線通信システム３００では、複数の基地局３１０、３２０、３３０が、複数のセルＣ３１、Ｃ３２、Ｃ３３を形成している。各セルＣ３１、Ｃ３２、Ｃ３３内には、アンテナ（ポイント）を有する複数のＲＲＨ３４０Ａ～３４０Ｌが配設されている。ＲＲＨ３４０Ａ～３４０Ｌは、アンテナおよび無線部を有し、ベースバンド処理部等が含まれるＢＢＵがそれぞれ別の位置に配置される。ＲＲＨ３４０Ａ～３４０ｌは、基地局３１０、３２０、３３０のセルＣ３１、Ｃ３２、Ｃ３３の端部にそれぞれ配置される。ＲＲＨ３４０Ａ～３４０ｌは、それぞれカバーエリアＥ４１Ａ～Ｅ４１Ｌを形成する。ＲＲＨ３４０Ａ～３４０Ｌに接続されるＢＢＵは、基地局３１０、３２０、３３０と略同一の位置にそれぞれ配置される。各ＲＲＨ３４０Ａ～３４０Ｌに対応するＢＢＵは、在圏するセルＣ３１、Ｃ３２、Ｃ３３を形成する基地局３１０、３２０、３３０と有線接続または一体化されており、各基地局３１０、３２０、３３０との間で協調スケジューリングが可能である。また、第４実施形態では、移動局１００は、基地局３１０配下のＲＲＨ３４０ＡのカバーエリアＥ３４０Ａに在圏するものとする。移動局１００の構成および動作は、第２実施形態の移動局１００と同じであるので、同じ符号を付して説明を省略する。 16, in the wireless communication system 300, a plurality of base stations 310, 320, and 330 form a plurality of cells C31, C32, and C33. In each cell C31, C32, C33, a plurality of RRHs 340A to 340L having antennas (points) are arranged. RRHs 340A to 340L each have an antenna and a radio unit, and BBUs including a baseband processing unit and the like are arranged at different positions. RRHs 340A to 340l are arranged at the ends of cells C31, C32, and C33 of base stations 310, 320, and 330, respectively. RRHs 340A to 340l form cover areas E41A to E41L, respectively. BBUs connected to RRHs 340A to 340L are arranged at substantially the same positions as base stations 310, 320, and 330, respectively. The BBUs corresponding to the RRHs 340A to 340L are connected or integrated with the base stations 310, 320, and 330 forming the cells C31, C32, and C33 that are in the area, and between the base stations 310, 320, and 330. Collaborative scheduling is possible. In the fourth embodiment, it is assumed that the mobile station 100 is located in the cover area E340A of the RRH 340A under the base station 310. Since the configuration and operation of the mobile station 100 are the same as those of the mobile station 100 of the second embodiment, the same reference numerals are given and description thereof is omitted.
　基地局３１０、３２０、３３０の機能的構成および動作は、第２実施形態の基地局６０と同様である。また、ＲＲＨ３４０Ａ～３４０Ｌの機能的構成および動作は、第３実施形態のＲＲＨ２３０Ａと同様である。 The functional configurations and operations of the base stations 310, 320, and 330 are the same as those of the base station 60 of the second embodiment. The functional configurations and operations of the RRHs 340A to 340L are the same as those of the RRH 230A of the third embodiment.
　無線通信システム３００のタイミング制御の動作では、第２実施形態の図１３の説明と同様にタイミング制御が実行される。例えば、上りリンクのＣｏＭＰ通信を行う基地局３１０、３２０、３３０と、ＲＲＨ３４０Ａ～３４０Ｌとの少なくとも一部について、合成後の受信信号の受信品質を最も高くする送信タイミングとして、基準となる送信タイミングが決定される。 In the timing control operation of the wireless communication system 300, timing control is executed in the same manner as in the description of FIG. 13 of the second embodiment. For example, for at least a part of the base stations 310, 320, and 330 that perform uplink CoMP communication and the RRHs 340A to 340L, a transmission timing that serves as a reference is used as a transmission timing that maximizes the reception quality of the combined received signal. It is determined.
　第４実施形態によれば、第２及び第３実施形態と同様に、上りリンクのＣｏＭＰ通信を行う無線通信システム３００において、受信特性を向上させることができる。 According to the fourth embodiment, similarly to the second and third embodiments, reception characteristics can be improved in the wireless communication system 300 that performs uplink CoMP communication.
　なお、第４実施形態では、各ＲＲＨのカバーエリアが同一セル内に存在することを前提として説明したが、各ＲＲＨのカバーエリアは、異なるセルを跨いで存在するものとしてもよい。 Although the fourth embodiment has been described on the assumption that the cover area of each RRH exists in the same cell, the cover area of each RRH may be present across different cells.
　また、第１～第４実施形態の無線通信システムは、例えば、ＬＴＥ－Ａシステムとして実現できる。なお、ＬＴＥ－Ａ以外の通信方式を用いた無線通信システムに適用することも可能である。 Further, the wireless communication systems of the first to fourth embodiments can be realized as, for example, an LTE-A system. Note that the present invention can also be applied to a wireless communication system using a communication method other than LTE-A.
　また、無線通信システムとして、例えば送信電力の異なる基地局が混在していたり、異なる種類の通信方式を用いた無線通信装置が混在しているような、ヘテロジニアスネットワークに適用することも可能である。 Further, as a wireless communication system, for example, it is also possible to apply to a heterogeneous network in which base stations having different transmission powers are mixed or wireless communication devices using different types of communication methods are mixed. .
　また、第１～第４実施形態において、基準となる送信タイミングを決定する条件は、各装置（無線通信装置、基地局、ＲＲＨ、アンテナなど）の設置位置や他の装置との配置関係、あるいは、各装置の運用状況や電波状態等の変更要因に応じて、適宜更新可能である。 In the first to fourth embodiments, the condition for determining the reference transmission timing is the installation position of each device (wireless communication device, base station, RRH, antenna, etc.), the arrangement relationship with other devices, or They can be updated as appropriate according to the changing factors such as the operation status and radio wave condition of each device.
　また、第１～第４実施形態は、移動局として、携帯電話機、スマートフォン、ＰＤＡ（Personal　Digital　Assistant）などの携帯端末に適用可能である。また、第１～第４実施形態は、その他、移動中継局など、基地局との間で通信を行う様々な通信機器に対して適用可能である。 Also, the first to fourth embodiments can be applied to mobile terminals such as mobile phones, smartphones, PDAs (Personal Digital Assistants) as mobile stations. In addition, the first to fourth embodiments can be applied to various communication devices that communicate with a base station such as a mobile relay station.
　また、第１～第４実施形態は、基地局として、マクロ基地局、フェムト基地局など、様々な規模の基地局に適用可能である。また、第１～第４実施形態は、その他、中継局など、移動局との間で通信を行う様々な通信機器に対して適用可能である。 Also, the first to fourth embodiments can be applied to base stations of various sizes such as macro base stations and femto base stations as base stations. In addition, the first to fourth embodiments can be applied to various communication devices that communicate with mobile stations such as relay stations.
　また、基地局、移動局の各構成要素の分散・統合の具体的態様は、第１～第４実施形態の態様に限定されず、その全部又は一部を、各種の負荷や使用状況等に応じて、任意の単位で機能的又は物理的に分散・統合して構成することもできる。例えば、メモリを、基地局、移動局の外部装置としてネットワークやケーブル経由で接続するようにしてもよい。 Further, the specific mode of distribution / integration of each component of the base station and mobile station is not limited to the mode of the first to fourth embodiments, and all or a part thereof can be used for various loads and usage conditions. Accordingly, it may be configured to be functionally or physically distributed / integrated in an arbitrary unit. For example, the memory may be connected via a network or a cable as an external device of the base station or mobile station.
　１，５０，２００，３００　無線通信システム
　１０，２０，３０　無線通信装置
　１１，２１，３１　アンテナ
　１２，２２，３２　送信部
　１３，２３，３３　受信部
　１４，２４，３４　制御部
　６０，８０，９０，３１０，３２０，３３０　基地局
　６０Ａ　ＤＳＰ
　６０Ｂ　ＦＰＧＡ
　６０Ｃ　メモリ
　６０Ｄ　ＲＦ回路
　６０Ｅ　ネットワークＩＦ
　６１　受信アンテナ
　６２，２３４Ａ　データ受信部
　６３，２３５Ａ　ＲＡＣＨ受信部
　６４，２３６Ａ　ＳＲＳ受信部
　６５　送信アンテナ
　６６，２３７Ａ　制御チャネル送信部
　６７，２３８Ａ　データチャネル送信部
　６８，２４０　データ復調部
　６９，２４１　データ復号部
　７０，２４２　受信バッファ
　７１，２４８　送信バッファ
　７２，２４３　タイミング検出部
　７３，２４４　受信品質測定部
　７４，２４５　スケジューラ部
　７５，２４６　ＵＬ　ｇｒａｎｔ生成部
　７６，２４７　ＴＡコマンド・ＲＡＲ生成部
　１００　移動局
　１００Ａ　ＣＰＵ
　１００Ｂ　メモリ
　１００Ｃ　ＲＦ回路
　１００Ｄ　表示装置
　１０１　送信アンテナ
　１０２　データ送信部
　１０３　ＳＲＳ送信部
　１０４　ＲＡＣＨ送信部
　１０５　受信アンテナ
　１０６　制御チャネル受信部
　１０７　データチャネル受信部
　１０８　送信バッファ
　１０９，１１０　アプリケーション処理部
　１１１　受信バッファ
　１１２　データ系列生成部
　１１３　送信タイミング制御部
　１１４　ＵＬ　ｇｒａｎｔ解析部
　１１５　上位レイヤ制御情報解析部
　２２０　ＢＢＵ
　２３０Ａ～２３０Ｃ，３４０Ａ～３４０Ｌ　ＲＲＨ
　２３１Ａ～２３１Ｃ　受信アンテナ
　２３２Ａ～２３２Ｃ　送信アンテナ
　２３３Ａ～２３３Ｃ　無線部
　Ｃ１，Ｃ２，Ｃ１１，Ｃ１２，Ｃ１３，Ｃ３１，Ｃ３２，Ｃ３３　セル
　Ｅ２１～Ｅ２３，Ｅ４１Ａ～Ｅ４１Ｌ　ＲＲＨのカバーエリア 1, 50, 200, 300 Wireless communication system 10, 20, 30 Wireless communication device 11, 21, 31 Antenna 12, 22, 32 Transmitter 13, 23, 33 Receiver 14, 24, 34 Controller 60, 80, 90 , 310, 320, 330 Base station 60A DSP
60B FPGA
60C memory 60D RF circuit 60E network IF
61 reception antenna 62,234A data reception unit 63,235A RACH reception unit 64,236A SRS reception unit 65 transmission antenna 66,237A control channel transmission unit 67,238A data channel transmission unit 68,240 data demodulation unit 69,241 data decoding unit 70,242 Reception buffer 71,248 Transmission buffer 72,243 Timing detection unit 73,244 Reception quality measurement unit 74,245 Scheduler unit 75,246 UL grant generation unit 76,247 TA command / RAR generation unit 100 Mobile station 100A CPU
100B memory 100C RF circuit 100D display device 101 transmitting antenna 102 data transmitting unit 103 SRS transmitting unit 104 RACH transmitting unit 105 receiving antenna 106 control channel receiving unit 107 data channel receiving unit 108 transmission buffer 109, 110 application processing unit 111 receiving buffer 112 data Sequence generation unit 113 Transmission timing control unit 114 UL grant analysis unit 115 Upper layer control information analysis unit 220 BBU
230A to 230C, 340A to 340L RRH
231A to 231C Reception antenna 232A to 232C Transmission antenna 233A to 233C Radio unit C1, C2, C11, C12, C13, C31, C32, C33 cells E21 to E23, E41A to E41L RRH cover area

Claims (23)

  1. 　複数の第１の無線通信装置で、第２の無線通信装置から送信されるデータを受信する無線通信システムにおいて、
    　前記複数の第１の無線通信装置に関する情報に基づく、送信タイミングに関する情報を、前記第２の無線通信装置に送信する第１の送信部と、
    　前記第２の無線通信装置から前記複数の第１の無線通信装置に、前記送信タイミングで前記データを送信する第２の送信部と、
    　を有することを特徴とする無線通信システム。
          In a wireless communication system that receives data transmitted from a second wireless communication device by a plurality of first wireless communication devices,
    A first transmission unit configured to transmit information regarding transmission timing to the second wireless communication device based on the information regarding the plurality of first wireless communication devices;
    A second transmission unit that transmits the data at the transmission timing from the second wireless communication device to the plurality of first wireless communication devices;
    A wireless communication system comprising:
  2. 　前記送信タイミングに関する情報は、前記複数の第１の無線通信装置のうちの所定の第１の無線通信装置を示す情報であり、
    　前記第２の送信部は、前記複数の第１の無線通信装置への複数の送信タイミングのうち、前記所定の第１の無線通信装置への送信タイミングで、前記データを前記複数の第１の無線通信装置に送信する、
    　ことを特徴とする請求項１に記載の無線通信システム。
          The information regarding the transmission timing is information indicating a predetermined first wireless communication device among the plurality of first wireless communication devices,
    The second transmission unit transmits the data to the plurality of first wireless communication devices at a transmission timing to the predetermined first wireless communication device among a plurality of transmission timings to the plurality of first wireless communication devices. Send to the wireless communication device,
    The wireless communication system according to claim 1.
  3. 　前記複数の第１の無線通信装置のうち少なくとも１つは、
    　前記複数の第１の無線通信装置に関する情報から、前記送信タイミングに関する情報を決定する決定部を有する
    　ことを特徴とする請求項１に記載の無線通信システム。
          At least one of the plurality of first wireless communication devices is
    The wireless communication system according to claim 1, further comprising: a determination unit that determines information related to the transmission timing from information related to the plurality of first wireless communication devices.
  4. 　前記決定部は、前記複数の第１の無線通信装置のそれぞれの受信品質に関する情報と、前記複数の第１の無線通信装置の受信タイミングの分布に関する情報との少なくともいずれかに基づいて、前記送信タイミングに関する情報を決定する、
    　ことを特徴とする請求項３に記載の無線通信システム。
          The determination unit is configured to transmit the transmission based on at least one of information on reception quality of each of the plurality of first wireless communication devices and information on reception timing distribution of the plurality of first wireless communication devices. Determine timing information,
    The wireless communication system according to claim 3.
  5. 　前記送信タイミングで前記第２の無線通信装置から送信され、前記複数の第１の無線通信装置でそれぞれ受信されるデータを合成する処理部を有し、
    　前記決定部は、前記合成後のデータの受信品質を示す値が高まるように、前記送信タイミングに関する情報を決定する、
    　ことを特徴とする請求項３又は４に記載の無線通信システム。
          A processing unit that combines data transmitted from the second wireless communication device at the transmission timing and received by each of the plurality of first wireless communication devices;
    The determination unit determines information on the transmission timing so that a value indicating reception quality of the combined data is increased.
    The wireless communication system according to claim 3, wherein the wireless communication system is a wireless communication system.
  6. 　前記第２の送信部は、前記複数の第１の無線通信装置に、ランダムアクセス信号をそれぞれ送信し、
    　前記第２の無線通信装置で、前記ランダムアクセス信号に対する前記複数の第１の無線通信装置からの応答信号から、前記複数の第１の無線通信装置への複数の送信タイミングの初期値をそれぞれ取得する制御部を有する、
    　ことを特徴とする請求項２～５のいずれかに記載の無線通信システム。
          The second transmission unit transmits a random access signal to each of the plurality of first wireless communication devices,
    The second wireless communication device acquires initial values of a plurality of transmission timings to the plurality of first wireless communication devices from response signals from the plurality of first wireless communication devices to the random access signal, respectively. Having a control unit to
    The wireless communication system according to any one of claims 2 to 5, characterized in that:
  7. 　前記第２の送信部は、前記複数の第１の無線通信装置から取得される、リファレンス信号を送信するための無線リソースの割り当て情報、に基づいて、前記複数の第１の無線通信装置に前記リファレンス信号を周期的にそれぞれ送信し、
    　前記制御部は、前記リファレンス信号に応じて前記複数の第１の無線通信装置から通知されるタイミング調整情報に基づいて、前記複数の第１の無線通信装置への複数の送信タイミングの値をそれぞれ更新する、
    　ことを特徴とする請求項６に記載の無線通信システム。
          The second transmission unit transmits the reference information to the plurality of first wireless communication devices based on radio resource allocation information for transmitting a reference signal acquired from the plurality of first wireless communication devices. Send each reference signal periodically,
    The control unit sets a plurality of transmission timing values to the plurality of first wireless communication devices based on timing adjustment information notified from the plurality of first wireless communication devices according to the reference signal, respectively. Update,
    The wireless communication system according to claim 6.
  8. 　複数の第１の無線通信装置で、第２の無線通信装置から送信されるデータを受信する無線通信方法であって、
    　前記複数の第１の無線通信装置に関する情報に基づく、送信タイミングに関する情報を、前記第２の無線通信装置に送信し、
    　前記第２の無線通信装置から前記複数の第１の無線通信装置に、前記送信タイミングで前記データを送信する、
    　ことを含む無線通信方法。
          A wireless communication method for receiving data transmitted from a second wireless communication device by a plurality of first wireless communication devices,
    Transmitting information related to transmission timing based on the information related to the plurality of first wireless communication devices to the second wireless communication device;
    Transmitting the data from the second wireless communication device to the plurality of first wireless communication devices at the transmission timing;
    A wireless communication method.
  9. 　前記送信タイミングに関する情報は、前記複数の第１の無線通信装置のうちの所定の第１の無線通信装置に関する情報であり、
    　前記複数の第１の無線通信装置への複数の送信タイミングのうち、前記所定の第１の無線通信装置への送信タイミングで、前記データを前記第２の無線通信装置から前記複数の第１の無線通信装置に送信する、
    　ことを含む請求項８に記載の無線通信方法。
          The information related to the transmission timing is information related to a predetermined first wireless communication device among the plurality of first wireless communication devices,
    Among the plurality of transmission timings to the plurality of first wireless communication devices, the data is transmitted from the second wireless communication device to the plurality of first timings at the transmission timing to the predetermined first wireless communication device. Send to the wireless communication device,
    The wireless communication method according to claim 8.
  10. 　前記複数の第１の無線通信装置のうち少なくとも１つで、前記複数の第１の無線通信装置に関する情報から、前記送信タイミングに関する情報を決定する、
    　ことを含む請求項８に記載の無線通信方法。
          At least one of the plurality of first wireless communication devices determines information related to the transmission timing from information related to the plurality of first wireless communication devices.
    The wireless communication method according to claim 8.
  11. 　前記決定で、前記複数の第１の無線通信装置のそれぞれの受信品質に関する情報と、前記複数の第１の無線通信装置の受信タイミングの分布に関する情報との少なくともいずれかに基づいて、前記送信タイミングに関する情報を決定する、
    　ことを含む請求項８に記載の無線通信方法。
          In the determination, the transmission timing is based on at least one of information on reception quality of each of the plurality of first wireless communication devices and information on distribution of reception timing of the plurality of first wireless communication devices. Determine information about,
    The wireless communication method according to claim 8.
  12. 　前記送信タイミングで前記第２の無線通信装置から送信され、前記複数の第１の無線通信装置でそれぞれ受信されるデータを合成し、
    　前記決定で、前記合成後のデータの受信品質を示す値が高まるように、前記送信タイミングに関する情報を決定する、
    　ことを含む請求項１０又は１１に記載の無線通信方法。
          Combining the data transmitted from the second wireless communication device at the transmission timing and received by the plurality of first wireless communication devices,
    In the determination, information on the transmission timing is determined so that a value indicating reception quality of the combined data is increased.
    The wireless communication method according to claim 10 or 11, further comprising:
  13. 　前記第２の無線通信装置から前記複数の第１の無線通信装置に、ランダムアクセス信号をそれぞれ送信し、
    　前記第２の無線通信装置で、前記ランダムアクセス信号に対する前記複数の第１の無線通信装置からの応答信号から、前記複数の第１の無線通信装置への複数の送信タイミングの初期値をそれぞれ取得する、
    　ことを含む請求項８～１２のいずれかに記載の無線通信方法。
          Random access signals are respectively transmitted from the second wireless communication device to the plurality of first wireless communication devices,
    The second wireless communication device acquires initial values of a plurality of transmission timings to the plurality of first wireless communication devices from response signals from the plurality of first wireless communication devices to the random access signal, respectively. To
    The wireless communication method according to claim 8, further comprising:
  14. 　前記第２の無線通信装置で、前記複数の第１の無線通信装置にリファレンス信号を送信するための無線リソースの割り当て情報をそれぞれ取得し、
    　前記第２の無線通信装置から前記複数の第１の無線通信装置に、前記割り当て情報に基づいてリファレンス信号を周期的にそれぞれ送信し、
    　前記第２の無線通信装置で、前記リファレンス信号に応じて前記複数の第１の無線通信装置から通知されるタイミング調整情報に基づいて、前記第１の無線通信装置への複数の送信タイミングの値をそれぞれ更新する、
    　ことを含む請求項１３に記載の無線通信方法。
          Each of the second wireless communication devices acquires radio resource allocation information for transmitting a reference signal to the plurality of first wireless communication devices,
    A reference signal is periodically transmitted from the second wireless communication device to the plurality of first wireless communication devices based on the allocation information,
    A plurality of transmission timing values to the first wireless communication device based on timing adjustment information notified from the plurality of first wireless communication devices according to the reference signal in the second wireless communication device. Update each,
    The wireless communication method according to claim 13.
  15. 　他の無線通信装置と協調して、第２の無線通信装置から送信されるデータを受信する無線通信装置において、
    　前記無線通信装置及び前記他の無線通信装置に関する情報に基づく、送信タイミングに関する情報を、前記第２の無線通信装置に送信する送信部と、
    　前記送信タイミングで前記第２の無線通信装置から送信されるデータを受信する受信部と、
    　を有することを特徴とする無線通信装置。
          In a wireless communication device that receives data transmitted from the second wireless communication device in cooperation with another wireless communication device,
    A transmission unit that transmits information related to transmission timing to the second wireless communication device based on the information related to the wireless communication device and the other wireless communication device;
    A receiver for receiving data transmitted from the second wireless communication device at the transmission timing;
    A wireless communication apparatus comprising:
  16. 　前記送信タイミングに関する情報は、前記無線通信装置及び前記他の無線通信装置のうちの所定の無線通信装置を示す情報であり、
    　前記受信部は、前記無線通信装置及び前記他の無線通信装置への複数の送信タイミングのうち、前記所定の無線通信装置への送信タイミングで、前記第２の無線通信装置から送信されるデータを受信する
    　ことを特徴とする請求項１５に記載の無線通信装置。
          The information on the transmission timing is information indicating a predetermined wireless communication device among the wireless communication device and the other wireless communication device,
    The receiving unit receives data transmitted from the second wireless communication device at a transmission timing to the predetermined wireless communication device among a plurality of transmission timings to the wireless communication device and the other wireless communication device. The wireless communication apparatus according to claim 15, wherein the wireless communication apparatus receives the wireless communication apparatus.
  17. 　前記無線通信装置及び前記他の無線通信装置に関する情報から、前記送信タイミングに関する情報を決定する決定部を有する
    　ことを特徴とする請求項１６に記載の無線通信装置。
          The wireless communication apparatus according to claim 16, further comprising: a determination unit that determines information regarding the transmission timing from information regarding the wireless communication apparatus and the other wireless communication apparatus.
  18. 　前記決定部は、前記無線通信装置及び前記他の無線通信装置のそれぞれの受信品質に関する情報と、前記無線通信装置及び前記他の無線通信装置の受信タイミングの分布に関する情報とに基づいて、前記送信タイミングに関する情報を決定する、
    　ことを特徴とする請求項１７に記載の無線通信装置。
          The determination unit is configured to transmit the transmission based on information on reception quality of each of the wireless communication device and the other wireless communication device and information on distribution of reception timings of the wireless communication device and the other wireless communication device. Determine timing information,
    The wireless communication apparatus according to claim 17.
  19. 　前記無線通信装置及び前記他の無線通信装置でそれぞれ受信される、前記送信タイミングで前記第２の無線通信装置から送信されるデータを、合成する処理部を有し、
    　前記決定部は、前記合成後のデータの受信品質を示す値が高まるように、前記送信タイミングに関する情報を決定する、
    　ことを特徴とする請求項１６又は１７に記載の無線通信装置。
          A processing unit that synthesizes data transmitted from the second wireless communication device at the transmission timing, respectively received by the wireless communication device and the other wireless communication device;
    The determination unit determines information on the transmission timing so that a value indicating reception quality of the combined data is increased.
    The wireless communication apparatus according to claim 16 or 17, characterized in that:
  20. 　無線通信装置であって、
    　前記無線通信装置から送信されるデータを受信する複数の第１の無線通信装置に関する情報に基づく、送信タイミングに関する情報を、前記第１の無線通信装置の少なくとも１つから受信する受信部と、
    　前記複数の第１の無線通信装置に、前記送信タイミングでデータを送信する送信部と、
    　を有することを特徴とする無線通信装置。
          A wireless communication device,
    A receiving unit that receives information on transmission timing based on information on a plurality of first wireless communication devices that receive data transmitted from the wireless communication device from at least one of the first wireless communication devices;
    A transmitter that transmits data to the plurality of first wireless communication devices at the transmission timing;
    A wireless communication apparatus comprising:
  21. 　前記送信タイミングに関する情報は、前記複数の第１の無線通信装置のうちの所定の第１の無線通信装置に関する情報であり、
    　前記送信部は、前記複数の第１の無線通信装置への複数の送信タイミングのうち、前記所定の第１の無線通信装置への送信タイミングで、前記データを前記複数の第１の無線通信装置に送信する、
    　ことを特徴とする請求項２０に記載の無線通信装置。
          The information related to the transmission timing is information related to a predetermined first wireless communication device among the plurality of first wireless communication devices,
    The transmission unit transmits the data to the plurality of first wireless communication devices at a transmission timing to the predetermined first wireless communication device among a plurality of transmission timings to the plurality of first wireless communication devices. Send to
    The wireless communication apparatus according to claim 20.
  22. 　前記送信部は、前記複数の第１の無線通信装置に、ランダムアクセス信号をそれぞれ送信し、
    　前記ランダムアクセス信号に対する前記複数の第１の無線通信装置からの応答信号から、前記複数の第１の無線通信装置への複数の送信タイミングの初期値をそれぞれ取得する制御部を有する、
    　ことを特徴とする請求項２１に記載の無線通信装置。
          The transmitter transmits a random access signal to each of the plurality of first wireless communication devices,
    A controller that acquires initial values of a plurality of transmission timings to the plurality of first wireless communication devices from response signals from the plurality of first wireless communication devices to the random access signal,
    The wireless communication apparatus according to claim 21, wherein:
  23. 　前記送信部は、前記複数の第１の無線通信装置から取得される、リファレンス信号を送信するための無線リソースの割り当て情報、に基づいて、前記複数の第１の無線通信装置に前記リファレンス信号を周期的にそれぞれ送信し、
    　前記制御部は、前記リファレンス信号に応じて前記複数の第１の無線通信装置から通知されるタイミング調整情報に基づいて、前記複数の第１の無線通信装置への複数の送信タイミングの値をそれぞれ更新する、
    　ことを特徴とする請求項２１又は２２に記載の無線通信装置。
          The transmission unit transmits the reference signal to the plurality of first wireless communication devices based on allocation information of a radio resource for transmitting a reference signal acquired from the plurality of first wireless communication devices. Send each periodically,
    The control unit sets a plurality of transmission timing values to the plurality of first wireless communication devices based on timing adjustment information notified from the plurality of first wireless communication devices according to the reference signal, respectively. Update,
    The wireless communication apparatus according to claim 21 or 22,
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