WO2018061168A1 - Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil - Google Patents

Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil Download PDF

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Publication number
WO2018061168A1
WO2018061168A1 PCT/JP2016/078957 JP2016078957W WO2018061168A1 WO 2018061168 A1 WO2018061168 A1 WO 2018061168A1 JP 2016078957 W JP2016078957 W JP 2016078957W WO 2018061168 A1 WO2018061168 A1 WO 2018061168A1
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Prior art keywords
wireless communication
communication device
channel state
communication apparatus
csi
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PCT/JP2016/078957
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English (en)
Japanese (ja)
Inventor
矢野　哲也
剛史 下村
田中　良紀
ジヤンミン ウー
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富士通株式会社
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Priority to PCT/JP2016/078957 priority Critical patent/WO2018061168A1/fr
Publication of WO2018061168A1 publication Critical patent/WO2018061168A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H04W28/18—Negotiating wireless communication parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices

Definitions

  • the present invention relates to a wireless communication device, a wireless communication system, and a wireless communication method.
  • LTE Long Term Evolution
  • a technique for transmitting channel quality data of a channel in a wireless communication system is known (for example, see Patent Document 1 below).
  • a technique is known that adjusts transmission power in accordance with reception sensitivity that is acquired as needed from a wireless transmission / reception unit connected to an antenna unit (for example, see Patent Document 2 below).
  • a technique is known in which any one modulation parameter is selected from a plurality of modulation parameters in accordance with the propagation path state estimation result (see, for example, Patent Document 3 below).
  • a technique for adjusting transmission in a distributed wireless system through user clustering is known (for example, see Patent Document 4 below).
  • CQI is an abbreviation for Channel Quality Indicator.
  • an object of the present invention is to provide a wireless communication device, a wireless communication system, and a wireless communication method capable of reducing an error rate in data transmission.
  • the first wireless communication apparatus measures a channel state in the own apparatus, and measures the channel state and the channel state. And a channel state measurement included in the signal received from the first wireless communication apparatus by a second wireless communication apparatus that transmits a signal including information on time change and transmits data to the first wireless communication apparatus.
  • An estimated value of the channel state between the device and the first wireless communication device is calculated using the value and the information on the time change of the channel state, and the first wireless communication is based on the calculated estimated value
  • a wireless communication device, a wireless communication system, and a wireless communication method that perform scheduling of data transmission to the device are proposed.
  • FIG. 1 is a diagram illustrating an example of a communication system according to the first embodiment.
  • FIG. 2 is a diagram illustrating an example of channel state reporting by the first wireless communication apparatus and data transmission by the second wireless communication apparatus according to the first embodiment.
  • FIG. 3 is a flowchart of an example of processing by the first wireless communication apparatus according to the first embodiment.
  • FIG. 4 is a flowchart of an example of processing by the second wireless communication apparatus according to the first embodiment.
  • FIG. 5 is a diagram of an example of the first wireless communication apparatus according to the first embodiment.
  • FIG. 6 is a diagram of an example of the second wireless communication apparatus according to the first embodiment.
  • FIG. 7 is a diagram of an example of a hardware configuration of the first wireless communication device and the second wireless communication device according to the first embodiment.
  • FIG. 8 is a diagram illustrating an example of calculation of a change amount of CSI based on measured values of CSI for the past two times by the first wireless communication apparatus according to the first embodiment.
  • FIG. 9 is a diagram illustrating another example of calculation of the change amount of CSI based on the measured values of CSI for the past two times by the first wireless communication apparatus according to the first embodiment.
  • FIG. 10 is a diagram illustrating an example of calculation of a change amount of CSI based on measured values of CSI for the past N times by the first wireless communication apparatus according to the first embodiment.
  • FIG. 11 is a diagram illustrating another example of the calculation of the CSI change amount based on the past N CSI measurement values by the first wireless communication apparatus according to the first embodiment.
  • FIG. 12 is a diagram of an example of a channel state report by the first wireless communication apparatus according to the second embodiment.
  • FIG. 13 is a flowchart of an example of processing by the first wireless communication apparatus according to the second embodiment.
  • FIG. 14 is a flowchart of an example of processing by the second wireless communication apparatus according to the second embodiment.
  • FIG. 15 is a diagram of an example of a channel state report by the first wireless communication apparatus according to the third embodiment.
  • FIG. 16 is a flowchart of an example of processing by the first wireless communication apparatus according to the third embodiment.
  • FIG. 17 is a diagram illustrating an example of calculation of the change amount of the CSI change amount by the first wireless communication apparatus according to the fourth embodiment.
  • FIG. 18 is a diagram of an example of channel state estimation performed by the second wireless communication apparatus according to the fifth embodiment.
  • FIG. 1 is a diagram illustrating an example of a communication system according to the first embodiment.
  • the communication system 100 according to the first embodiment includes a first wireless communication device 110 and a second wireless communication device 120.
  • the first wireless communication device 110 receives data wirelessly transmitted from the second wireless communication device 120.
  • the data transmitted from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 is user data transmitted by U-Plane, for example.
  • the first wireless communication device 110 can be applied to a wireless terminal
  • the second wireless communication device 120 can be applied to a wireless base station.
  • the wireless terminal is a mobile station such as a 3GPP UE (User Equipment: user terminal).
  • the radio base station is various base stations such as eNB (evolved Node B) of 3GPP, for example.
  • the first wireless communication apparatus 110 includes, for example, a measurement unit 111 and a transmission unit 112.
  • the measurement unit 111 measures the channel state in the first wireless communication apparatus 110 (self apparatus). Then, the measurement unit 111 notifies the transmission unit 112 of the measurement result of the channel state in the first wireless communication apparatus 110.
  • the channel state in the first wireless communication device 110 is a channel state between the first wireless communication device 110 and the second wireless communication device 120, for example.
  • the channel state is, for example, CSI (Channel State Information) indicating the state of the wireless channel through which the signal passes.
  • the specific content of CSI is, for example, any one of SINR, CQI, MCS level, interference amount, and the like.
  • SINR Signal to Interference and Noise Ratio
  • the CQI is an identifier represented by a modulation and coding scheme that can be transmitted with the measured SINR.
  • the MCS (Modulation and Coding Scheme) level is a level that represents a modulation and coding scheme that can be transmitted with the measured SINR.
  • the interference level is the amount of interference signal included in the received signal.
  • the transmission unit 112 Based on the measurement result notified from the measurement unit 111, the transmission unit 112 includes a measurement value of the channel state in the first wireless communication device 110 and information regarding a time change of the channel state in the first wireless communication device 110. Generate a report signal. Then, the transmission unit 112 wirelessly transmits the generated report signal to the second wireless communication apparatus 120.
  • PUCCH Physical Uplink Control Channel: physical uplink control channel
  • other (physical) channels for transmitting control information can be used.
  • a (physical) channel for data transmission such as PUSCH (Physical Uplink Shared Channel: physical uplink shared channel) may be used.
  • the measurement value included in the report signal is, for example, the measurement value (latest measurement value) obtained at the end of the measurement values obtained by the measurement unit 111.
  • the information related to the time change of the channel state included in the report signal is information based on a plurality of measurement values obtained by measuring the channel state a plurality of times by the measurement unit 111, for example.
  • the information regarding the channel state change over time is the rate of change (change amount) of the channel state over time, that is, the rate of change of the channel state over time.
  • the second wireless communication device 120 includes a receiving unit 121 and a control unit 122.
  • the receiving unit 121 receives a report signal transmitted from the first wireless communication apparatus 110. Then, the reception unit 121 outputs the received report signal to the control unit 122.
  • the control unit 122 uses the measured value of the channel state included in the report signal output from the receiving unit 121 and the information regarding the time change of the channel state, and the second wireless communication device 120 (self device) and the first wireless device.
  • An estimated value of the channel state with the communication device 110 is calculated.
  • the control unit 122 estimates the channel state between the second wireless communication device 120 and the first wireless communication device 110 (predicted value) in a future time resource that can transmit data to the first wireless communication device 110. ) Is calculated. Then, the control unit 122 schedules data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 based on the calculated estimated value of the channel state.
  • the scheduling by the control unit 122 includes, for example, determination of at least one of a modulation scheme and a coding scheme used for data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110.
  • the determination of the modulation scheme and the encoding scheme is, for example, the determination of MCS (Modulation and Coding Scheme: modulation / coding scheme).
  • the scheduling by the control unit 122 includes, for example, determination of the position of the radio resource on the frequency axis and the amount of the radio resource used for data transmission from the second radio communication apparatus 120 to the first radio communication apparatus 110. Also good. Further, the scheduling by the control unit 122 may include determination of transmission power used for data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110, for example.
  • the second wireless communication apparatus 120 transmits data to the first wireless communication apparatus 110 based on the scheduling result by the control unit 122.
  • the first wireless communication apparatus 110 transmits a report signal including the measured value of the channel state in the own apparatus and the information on the time change of the channel state in the own apparatus to the second wireless communication apparatus. 120. Also, the second wireless communication device 120 and the first wireless device and the first wireless device calculated by using the channel state measurement value included in the report signal received from the first wireless communication device 110 and the information on the channel state temporal change. Scheduling of data transmission to the first wireless communication device is performed based on the estimated value of the channel state with the communication device 110.
  • the frequency of reporting measurement values is less than the configuration in which the second radio communication device 120 predicts a change in channel state based on each measurement value of the channel state periodically reported by the first radio communication device 110.
  • the channel state can be predicted with high accuracy.
  • the second wireless communication device 120 performs scheduling. It is possible to predict the channel state of the variable time resource used for. For this reason, for example, the first radio communication apparatus 110 does not have to report an estimated value of the channel state in each future time resource, so that the efficiency of radio resources for reporting and the power consumption for reporting are reduced. Can be planned. In addition, since it is not necessary to limit the time resource used by second wireless communication apparatus 120 for scheduling, it is possible to suppress a decrease in the degree of freedom of scheduling in second wireless communication apparatus 120.
  • FIG. 2 is a diagram illustrating an example of channel state reporting by the first wireless communication apparatus and data transmission by the second wireless communication apparatus according to the first embodiment.
  • the horizontal axis indicates time
  • the vertical axis indicates CSI (channel state).
  • the subframe 201 on the horizontal axis is a unit of time (for example, 1 [ms]) in which CSI measurement and reporting by the first wireless communication device 110 and data transmission by the second wireless communication device 120 can be performed.
  • Times T ( ⁇ 3) to T (4) are successive times in subframe units.
  • the measured value a0 is CSI (intercept) measured by the first wireless communication apparatus 110 at time T (0).
  • the change amount a1 is a change amount (gradient) of CSI per time calculated by the first wireless communication apparatus 110 based on a plurality of past CSI measurement results.
  • the first wireless communication device 110 transmits a report signal including the measurement value a0 and the change amount a1 to the second wireless communication device 120 at time T (1) immediately after time T (0), thereby measuring the measurement value a0 and The change amount a1 is reported to the second wireless communication apparatus 120.
  • the second wireless communication device 120 uses the first CSI estimated value between the second wireless communication device 120 and the first wireless communication device 110 at a time after the time T (1), for example, T (4), as the first value. Calculation is performed using the measured value a0 and the change amount a1 reported from the wireless communication apparatus 110.
  • the predicted CSI characteristic 202 is CSI in each time interval predicted by the measured value a0 (intercept) and the change amount a1 (slope) that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120.
  • Second wireless communication apparatus 120 calculates an estimated value of CSI between second wireless communication apparatus 120 and first wireless communication apparatus 110 at time T (4) based on predicted CSI characteristic 202.
  • the time difference t is a difference between time T (0) and time T (4) (elapsed time from T (0)).
  • the second wireless communication apparatus 120 calculates an estimated value of CSI between the second wireless communication apparatus 120 and the first wireless communication apparatus 110 at time T (4) by calculating a1 * t + a0. Then, second wireless communication apparatus 120 performs scheduling of data to be transmitted to first wireless communication apparatus 110 based on the estimated CSI value at calculated time T (4), and first wireless communication apparatus at time T (4). Data transmission to the communication device 110 is performed.
  • the first wireless communication device 110 May notify the second wireless communication apparatus 120 of this time difference.
  • the second wireless communication apparatus 120 receives the time difference notified from the first wireless communication apparatus 110, the time T (1) when the report from the first wireless communication apparatus 110 is performed, and the time T when data transmission is performed. Based on (4), the time difference t can be calculated.
  • the transmission of the report signal from the first wireless communication apparatus 110 to the second wireless communication apparatus 120 can be realized, for example, by assigning in advance a dedicated resource of the first wireless communication apparatus 110 for transmitting the report signal. . This eliminates a collision between the report signal from the first wireless communication apparatus 110 and another signal (for example, a report signal from another wireless communication apparatus), thereby reducing error in the report signal.
  • the transmission of the report signal from the first wireless communication device 110 to the second wireless communication device 120 is performed by, for example, preallocating contention resources for a plurality of wireless communication devices including the first wireless communication device 110 to transmit the report signal. This can be realized. Thereby, it is possible to reduce the resource consumption in the transmission of the report signal.
  • FIG. 3 is a flowchart of an example of processing by the first wireless communication apparatus according to the first embodiment.
  • the first wireless communication apparatus 110 according to the first embodiment executes the steps shown in FIG. 3, for example.
  • the first wireless communication device 110 determines whether or not it is the periodic CSI reporting timing of the device itself (step S301).
  • the periodic CSI reporting timing may be, for example, a reporting timing instructed by the second wireless communication apparatus 120 to the first wireless communication apparatus 110 in advance, or may be determined by the first wireless communication apparatus 110. It may be the timing for reporting to the second wireless communication apparatus 120. Further, the periodic CSI report timing may be a known report timing (for example, every subframe or every several subframes) in the first radio communication apparatus 110 and the second radio communication apparatus 120.
  • step S301 when it is not the periodic CSI reporting timing (step S301: No), the first wireless communication apparatus 110 proceeds to step S303.
  • the periodic CSI reporting timing comes (step S301: Yes)
  • the first wireless communication apparatus 110 obtains the latest measured value of CSI and the amount of change in CSI based on past measured values of CSI.
  • the report signal shown is transmitted to the second wireless communication apparatus 120 (step S302).
  • the latest measured value of CSI is, for example, the above-described measured value a0.
  • the change amount of CSI is, for example, the change amount a1 described above.
  • the first wireless communication device 110 determines whether or not it has received a control signal addressed to itself from the second wireless communication device 120 (step S303).
  • the control signal is a signal including control information for notifying transmission of data from the second wireless communication apparatus 120 to the first wireless communication apparatus 110, for example.
  • the control signal is not received (step S303: No)
  • the first wireless communication device 110 returns to step S301.
  • step S303 when a control signal is received (step S303: Yes), the first wireless communication device 110 receives data from the second wireless communication device 120 based on the received control signal (step S304), Return to step S301.
  • the first wireless communication device 110 reports, for example, the CSI measurement value and the change amount to the second wireless communication device 120 at a periodic report timing.
  • wireless communication apparatus 110 receives the data from the 2nd radio
  • FIG. 4 is a flowchart of an example of processing by the second wireless communication apparatus according to the first embodiment.
  • the second radio communication apparatus 120 according to the first embodiment executes, for example, each step illustrated in FIG. First, the second wireless communication device 120 determines whether or not the periodic CSI reporting timing by the first wireless communication device 110 has come (step S401).
  • step S401 when the report timing has not come (step S401: No), the second wireless communication apparatus 120 proceeds to step S403.
  • the second wireless communication apparatus 120 receives a first report signal indicating the latest measured value of CSI by the first wireless communication apparatus 110 and the amount of change in CSI. Received from the wireless communication device 110 (step S402).
  • the second wireless communication apparatus 120 calculates CSI in a future time resource using the CSI measurement value included in the report signal received in step S402 and the amount of change in CSI (step S403).
  • Future time resources are, for example, one or more time resources that can be used to transmit data from the second wireless communication device 120 to the first wireless communication device 110.
  • the second wireless communication apparatus 120 performs scheduling based on the CSI calculated in step S403 (step S404).
  • Scheduling includes, for example, determination of radio resources, determination of modulation scheme and coding scheme.
  • the determination of radio resources is, for example, determination of the location and amount of resource blocks.
  • the determination of the encoding method is, for example, determination of a coding rate and a transport block size (data size).
  • the second wireless communication apparatus 120 determines whether to transmit data to the first wireless communication apparatus 110 based on the scheduling result of step S404 (step S405). When it is determined that data is not transmitted to the first wireless communication device 110 (step S405: No), the second wireless communication device 120 returns to step S401.
  • step S405 If it is determined in step S405 that data is transmitted to the first wireless communication apparatus 110 (step S405: Yes), the second wireless communication apparatus 120 transmits a control signal to the first wireless communication apparatus 110 (step S406).
  • the control signal transmitted in step S406 is a control signal for notifying transmission of data from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 based on the scheduling result in step S404.
  • the second wireless communication apparatus 120 transmits data to the first wireless communication apparatus 110 based on the scheduling result of step S404 (step S407), and returns to step S401.
  • the second wireless communication device 120 receives, for example, a report signal indicating a measured value and a change amount of CSI from the first wireless communication device 110 at a periodic report timing. Then, second radio communication apparatus 120 performs scheduling based on the received report signal, and transmits data to first radio communication apparatus 110 based on the scheduling result.
  • FIG. 5 is a diagram of an example of the first wireless communication apparatus according to the first embodiment.
  • the first wireless communication apparatus 110 according to the first embodiment includes, for example, a reception antenna 511, an RF reception unit 512, an ADC 513, a demodulation unit 514, a measurement unit 515, and a decoding unit 516. And comprising.
  • the first wireless communication apparatus 110 includes, for example, a control unit 520, an encoding unit 531, a modulation unit 532, a DAC 533, an RF transmission unit 534, and a transmission antenna 535.
  • ADC is an abbreviation for Analog / Digital Converter.
  • the DAC is an abbreviation for Digital / Analog Converter.
  • RF is an abbreviation for Radio Frequency.
  • the receiving antenna 511 receives a signal wirelessly transmitted from another wireless communication device such as the second wireless communication device 120. Then, the receiving antenna 511 outputs the received signal to the RF receiving unit 512.
  • the RF reception unit 512 performs an RF reception process on the signal output from the reception antenna 511.
  • the RF reception processing by the RF reception unit 512 includes, for example, amplification and frequency conversion from a high frequency band to a baseband.
  • the RF reception unit 512 outputs a signal subjected to the RF reception process to the ADC 513.
  • the ADC 513 converts the signal output from the RF receiver 512 from an analog signal to a digital signal. Then, ADC 513 outputs the signal converted into the digital signal to demodulation section 514.
  • the demodulator 514 demodulates the signal output from the ADC 513. Then, demodulation section 514 outputs the demodulated signal to measurement section 515 and decoding section 516.
  • Measurement unit 515 measures the channel state based on the signal output from demodulation unit 514. For example, the measurement unit 515 measures CSI based on RS (Reference Signal) from the second wireless communication apparatus 120 included in the signal output from the demodulation unit 514. Then, the measurement unit 515 outputs the CSI measurement value to the control unit 520.
  • the decoding unit 516 decodes the signal output from the demodulation unit 514. Then, the decoding unit 516 outputs a signal obtained by the decoding to the control unit 520.
  • the control unit 520 controls wireless communication by the first wireless communication device 110. For example, the control unit 520 outputs the data output from the decoding unit 516 to an upper processing unit in the first wireless communication apparatus 110. In addition, the control unit 520 generates the above-described report signal based on the CSI measurement value output from the measurement unit 515. In addition, the control unit 520 outputs a signal to be transmitted to another wireless communication device such as the second wireless communication device 120 to the encoding unit 531.
  • the signal output from the control unit 520 to the encoding unit 531 includes the generated report signal, data output from a higher-level processing unit in the first wireless communication apparatus 110, and the like.
  • the encoding unit 531 encodes the signal output from the control unit 520. Then, the encoding unit 531 outputs a signal obtained by encoding to the modulation unit 532.
  • the modulation unit 532 performs modulation based on the signal output from the encoding unit 531. Then, the modulation unit 532 outputs a signal obtained by the modulation to the DAC 533.
  • the DAC 533 converts the signal output from the modulation unit 532 from a digital signal to an analog signal. Then, the DAC 533 outputs the signal converted into the analog signal to the RF transmission unit 534.
  • the RF transmission unit 534 performs RF transmission processing on the signal output from the DAC 533.
  • the RF transmission processing by the RF transmission unit 534 includes, for example, frequency conversion or amplification from a baseband to a high frequency band.
  • the RF transmission unit 534 outputs the signal subjected to the RF transmission process to the transmission antenna 535.
  • the transmission antenna 535 wirelessly transmits the signal output from the RF transmission unit 534 to another wireless communication device such as the second wireless communication device 120.
  • FIG. 6 is a diagram of an example of the second wireless communication apparatus according to the first embodiment.
  • the second wireless communication apparatus 120 according to the first embodiment includes, for example, a reception antenna 611, an RF reception unit 612, an ADC 613, a demodulation unit 614, and a decoding unit 615.
  • the second wireless communication apparatus 120 includes, for example, a control unit 621, a CSI calculation unit 622, a scheduler 623, an encoding unit 631, a modulation unit 632, a DAC 633, an RF transmission unit 634, and a transmission antenna 635. And comprising.
  • the receiving antenna 611 receives a signal wirelessly transmitted from another wireless communication device such as the first wireless communication device 110. Then, the receiving antenna 611 outputs the received signal to the RF receiving unit 612. The RF reception unit 612 performs RF reception processing on the signal output from the reception antenna 611.
  • the RF reception processing by the RF receiver 612 includes, for example, amplification and frequency conversion from a high frequency band to a baseband.
  • the RF receiving unit 612 outputs the signal subjected to the RF receiving process to the ADC 613.
  • the ADC 613 converts the signal output from the RF receiving unit 612 from an analog signal to a digital signal. Then, the ADC 613 outputs the signal converted into the digital signal to the demodulation unit 614.
  • the demodulator 614 demodulates the signal output from the ADC 613. Demodulation section 614 then outputs the demodulated signal to decoding section 615.
  • the decoding unit 615 decodes the signal output from the demodulation unit 614. Then, the decoding unit 615 outputs the signal obtained by the decoding to the control unit 621.
  • the control unit 621 controls wireless communication by the second wireless communication device 120. For example, the control unit 621 outputs data included in the signal output from the decoding unit 615 to an upper processing unit in the second wireless communication apparatus 120. In addition, the control unit 621 outputs a signal to be transmitted to another wireless communication device such as the first wireless communication device 110 to the encoding unit 631.
  • the signal output from the control unit 621 to the encoding unit 631 includes data output from a higher-level processing unit in the second wireless communication apparatus 120.
  • control unit 621 outputs the report signal from the first wireless communication apparatus 110 included in the signal output from the decoding unit 615 to the CSI calculation unit 622. Further, the control unit 621 controls scheduling in the scheduler 623.
  • the CSI calculation unit 622 calculates an estimated value of CSI of radio transmission from the first radio communication device 110 to the second radio communication device 120 in a future time resource based on the report signal output from the control unit 621. In addition, the CSI calculation unit 622 may calculate each estimated value of CSI in a plurality of future time resources. Then, the CSI calculation unit 622 outputs the calculated estimated CSI value to the scheduler 623.
  • the scheduler 623 schedules data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 based on the estimated CSI value output from the CSI calculation section 622 according to the control from the control section 621. Then, the scheduler 623 notifies the encoding unit 631 of the scheduling result.
  • the result of scheduling includes, for example, radio resources used for data transmission from the second radio communication apparatus 120 to the first radio communication apparatus 110, MCS, transmission power, and the like.
  • the radio resource is, for example, a combination of time resource and frequency resource.
  • the encoding unit 631 encodes the signal output from the control unit 621 based on the scheduling result notified from the scheduler 623. Then, encoding section 631 outputs a signal obtained by encoding to modulation section 632.
  • the modulation unit 632 performs modulation based on the signal output from the encoding unit 631. Then, the modulation unit 632 outputs a signal obtained by the modulation to the DAC 633.
  • the DAC 633 converts the signal output from the modulation unit 632 from a digital signal to an analog signal. Then, the DAC 633 outputs the signal converted into the analog signal to the RF transmission unit 634.
  • the RF transmission unit 634 performs an RF transmission process on the signal output from the DAC 633.
  • the RF transmission processing by the RF transmission unit 634 includes, for example, frequency conversion or amplification from a baseband to a high frequency band.
  • the RF transmission unit 634 outputs the signal subjected to the RF transmission process to the transmission antenna 635.
  • the transmission antenna 635 wirelessly transmits the signal output from the RF transmission unit 634 to another wireless communication device such as the first wireless communication device 110.
  • FIG. 7 is a diagram of an example of a hardware configuration of the first wireless communication device and the second wireless communication device according to the first embodiment.
  • the communication device 700 includes a processor 701, a memory 702, and a wireless communication interface 703.
  • the processor 701, the memory 702, and the wireless communication interface 703 are connected by a bus 709, for example.
  • the processor 701 is a circuit that performs signal processing, for example, a CPU (Central Processing Unit) that controls the entire communication device 700.
  • the memory 702 includes, for example, a main memory and an auxiliary memory.
  • the main memory is, for example, a RAM (Random Access Memory).
  • the main memory is used as a work area for the processor 701.
  • the auxiliary memory is, for example, a nonvolatile memory such as a magnetic disk, an optical disk, or a flash memory.
  • Various programs for operating the communication device 700 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the processor 701.
  • processor 701 and the memory 702 may be realized by a digital circuit such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor).
  • processor 701 and the memory 702 may be realized by an LSI (Large Scale Integrated circuit).
  • the wireless communication interface 703 is a communication interface that performs communication with the outside of the communication device 700 wirelessly.
  • the wireless communication interface 703 is controlled by the processor 701.
  • the demodulation unit 514, the measurement unit 515, the decoding unit 516, the control unit 520, the encoding unit 531 and the modulation unit 532 illustrated in FIG. 5 are realized by the processor 701, for example.
  • the measurement unit 111 and the transmission unit 112 illustrated in FIG. 1 can be realized by the processor 701 controlling the wireless communication interface 703, for example.
  • the demodulation unit 614, the decoding unit 615, the control unit 621, the CSI calculation unit 622, the scheduler 623, the encoding unit 631, and the modulation unit 632 illustrated in FIG. 6 are realized by the processor 701, for example.
  • the reception unit 121 illustrated in FIG. 1 can be realized by the processor 701 controlling the wireless communication interface 703, for example.
  • the control unit 122 illustrated in FIG. 1 can be realized by the processor 701, for example.
  • the communication apparatus 700 includes a wired communication interface that performs communication with a host apparatus. May be.
  • the wired communication interface is controlled by the processor 701.
  • FIG. 8 is a diagram illustrating an example of calculation of a change amount of CSI based on measured values of CSI for the past two times by the first wireless communication apparatus according to the first embodiment.
  • first radio communication apparatus 110 measures CSI in each subframe 201.
  • CSI (-1) is CSI measured by the first wireless communication apparatus 110 at time T (-1).
  • CSI (0) is CSI measured by first radio communication apparatus 110 at time T (0) immediately after time T ( ⁇ 1).
  • the measurement interval T is a time interval between times T ( ⁇ 1) and T (0) when CSI ( ⁇ 1) and CSI (0) are measured.
  • the first wireless communication device 110 transmits the report signal including the measurement value a0 and the change amount a1 to the second wireless communication device 120 at the time T (1) immediately after the time T (0).
  • the a0 and the change amount a1 are reported to the second wireless communication apparatus 120.
  • the predicted CSI characteristic 821 is CSI in each time interval predicted by the measured value a0 (intercept) and the change amount a1 (slope) that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120.
  • Second radio communication apparatus 120 calculates an estimated value of CSI between second radio communication apparatus 120 and first radio communication apparatus 110 in a time interval after time T (1) based on predicted CSI characteristic 821. .
  • the first wireless communication apparatus 110 calculates the change amount a1 by dividing the difference between the measured values of the CSI for the past two times by the difference between the measurement times (measurement interval T), for example. can do.
  • FIG. 9 is a diagram illustrating another example of the calculation of the change amount of CSI based on the measured values of CSI for the past two times by the first wireless communication apparatus according to the first embodiment.
  • the same parts as those shown in FIG. 9 are identical parts as those shown in FIG. 9 in FIG. 9, the same parts as those shown in FIG. 9
  • the CSI measurement result 911 illustrated in FIG. 9 indicates the CSI by the first wireless communication device 110 in each time interval including the time interval after the time T (1) when the first wireless communication device 110 reports to the second wireless communication device 120. It is a measurement result. As shown in the CSI measurement result 911, the measured value of CSI after the first wireless communication device 110 reports the measured value a0 and the change amount a1 to the second wireless communication device 120 is based on the measured value a0 and the change amount a1.
  • the CSI predicted by the predicted CSI characteristic 821 may be lower. In the example illustrated in FIG. 9, the measured value of CSI is lower than the CSI predicted by the predicted CSI characteristic 821 at time T (4).
  • the value of ⁇ may be a constant value. For example, if the change in CSI is convex upward (while the slope is decreasing), ⁇ is increased or the change in CSI is convex downward (slope If ⁇ is increasing), ⁇ may be decreased. Further, ⁇ may be increased if there is an error in the decoding result of the data received by the first wireless communication apparatus in the past predetermined period.
  • the first wireless communication device 110 transmits the measurement value a0 and the change amount a1 ′ by transmitting a report signal including the measurement value a0 and the change amount a1 ′ to the second wireless communication device 120 at time T (1).
  • the predicted CSI characteristic 921 is CSI in each time interval predicted by the measured value a0 and the change amount a1 ′ that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120.
  • the second wireless communication apparatus 120 calculates the estimated CSI value between the second wireless communication apparatus 120 and the first wireless communication apparatus 110 in the time interval after the time T (1) as a predicted CSI characteristic 921 (a1 ′ * t + a0). ). Thereby, the 2nd radio
  • the configuration in which the first wireless communication apparatus 110 calculates the change amount a1 'has been described the configuration is not limited to such a configuration.
  • FIG. 10 is a diagram illustrating an example of calculation of a change amount of CSI based on measured values of CSI for the past N times by the first wireless communication apparatus according to the first embodiment.
  • the same parts as those shown in FIG. 10 are identical parts as those shown in FIG. 10
  • CSI ( ⁇ 4) is CSI measured by the first wireless communication apparatus 110 at time T ( ⁇ 4).
  • CSI ( ⁇ 3) is CSI measured by first radio communication apparatus 110 at time T ( ⁇ 3) immediately after time T ( ⁇ 4).
  • CSI ( ⁇ 2) is CSI measured by first radio communication apparatus 110 at time T ( ⁇ 2) immediately after time T ( ⁇ 3).
  • CSI ( ⁇ 1) is CSI measured by first radio communication apparatus 110 at time T ( ⁇ 1) immediately after time T ( ⁇ 2).
  • CSI (0) is CSI measured by first radio communication apparatus 110 at time T (0) immediately after time T ( ⁇ 1). That is, CSI ( ⁇ n) is a measurement value n times before the latest measurement value.
  • the measurement interval T is a time interval between times T ( ⁇ 1) and T (0) when CSI ( ⁇ 1) and CSI (0) are measured.
  • the first wireless communication apparatus 110 uses the CSI (0) measured at time T (0) as the measurement value a0 (intercept), as in the example of FIG.
  • the first wireless communication device 110 transmits the report signal including the measurement value a0 and the change amount a1 to the second wireless communication device 120 at the time T (1) immediately after the time T (0).
  • the a0 and the change amount a1 are reported to the second wireless communication apparatus 120.
  • the predicted CSI characteristic 1021 is CSI in each time interval predicted by the measured value a0 and the change amount a1 that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120.
  • Second wireless communication apparatus 120 calculates an estimated value of CSI between second wireless communication apparatus 120 and first wireless communication apparatus 110 in a time interval after time T (1) based on predicted CSI characteristic 1021. .
  • the first wireless communication apparatus 110 divides the worst value of the difference in CSI measurement values for the past N times by the difference in measurement time (measurement interval T), for example. Can be calculated.
  • FIG. 11 is a diagram illustrating another example of calculation of the change amount of CSI based on the measured values of CSI for the past N times by the first wireless communication apparatus according to the first embodiment. 11, the same parts as those shown in FIG. 10 are denoted by the same reference numerals, and the description thereof is omitted.
  • the CSI measurement result 1111 shown in FIG. 11 indicates the CSI by the first radio communication device 110 in each time interval including the time interval after the time T (1) when the first radio communication device 110 reports to the second radio communication device 120. It is a measurement result. As shown in the CSI measurement result 1111, the CSI measurement value after the first wireless communication device 110 reports the measurement value a0 and the change amount a1 to the second wireless communication device 120 is based on the measurement value a0 and the change amount a1. It may be lower than the CSI predicted by the predicted CSI characteristic 1021.
  • the first wireless communication device 110 transmits the measurement value a0 and the change amount a1 ′ by transmitting a report signal including the measurement value a0 and the change amount a1 ′ to the second wireless communication device 120 at time T (1).
  • the predicted CSI characteristic 1121 is CSI in each time interval predicted by the measured value a0 and the change amount a1 'that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120.
  • Second wireless communication apparatus 120 calculates an estimated value of CSI between second wireless communication apparatus 120 and first wireless communication apparatus 110 in a time interval after time T (1) based on predicted CSI characteristic 1121. . Thereby, the 2nd radio
  • wireless communication apparatus 120 can perform scheduling supposing that CSI worsens. For this reason, even if the CSI in each time interval after time T (1) becomes, for example, the CSI measurement result 1111, the communication quality of data transmission from the second wireless communication device 120 to the first wireless communication device 110 is the reference. It can suppress falling below a value.
  • the configuration in which the first wireless communication apparatus 110 calculates the change amount a1 'has been described the configuration is not limited to such a configuration.
  • the first wireless communication apparatus 110 calculates a difference for each combination of the measured values of the CSI for the latest N times, not just the difference between the measured values whose measurement times are adjacent to each other, and measures the worst value of the calculated difference.
  • the change amount a1 (slope) may be obtained by dividing by the interval T.
  • the first wireless communication apparatus 110 transmits the report signal including the measured value of the channel state in the own apparatus and the information on the time change of the channel state in the own apparatus to the second radio. Transmit to the communication device 120. Also, the second wireless communication device 120 and the first wireless device and the first wireless device calculated by using the channel state measurement value included in the report signal received from the first wireless communication device 110 and the information on the channel state temporal change. Scheduling of data transmission to the first wireless communication device is performed based on the estimated value of the channel state with the communication device 110.
  • the frequency of reporting measurement values is less than the configuration in which the second radio communication device 120 predicts a change in channel state based on each measurement value of the channel state periodically reported by the first radio communication device 110.
  • the channel state can be predicted with high accuracy.
  • the first wireless communication device 110 includes information on the past channel state measurement value and the channel state time change included in the report signal transmitted to the second wireless communication device 120 as the channel state measurement value at a certain time. And the latest report signal may be transmitted to the second radio communication apparatus 120 when the estimated value of the channel state at that time is worse than that calculated using. Thereby, even if the frequency of reports from the first wireless communication device 110 to the second wireless communication device 120 is low, the communication quality of data transmission from the second wireless communication device 120 to the first wireless communication device 110 becomes the reference value. It is possible to suppress lowering.
  • the first wireless communication apparatus 110 includes information indicating any one of a state in which the channel state is deteriorated, a state in which the channel state is constant, and a state in which the channel state is improved as the information regarding the time change of the channel state. It may be transmitted by a report signal.
  • the state where the channel state is deteriorated is, for example, a state where CSI (0) ⁇ CSI ( ⁇ 1), which is the difference between the latest CSI (0) and the previous CSI ( ⁇ 1), is a negative value. It is.
  • the state where the channel state is constant is, for example, a state where CSI (0) ⁇ CSI ( ⁇ 1) which is the difference between the most recent CSI (0) and the previous CSI ( ⁇ 1) is zero.
  • the state in which the channel state is improved is, for example, a state in which CSI (0) ⁇ CSI ( ⁇ 1), which is the difference between the most recent CSI (0) and the previous CSI ( ⁇ 1), is a positive value. It is.
  • the first wireless communication apparatus 110 reports the measured value of the channel state and information indicating that the channel state is in a fixed state or an improved state to the second wireless communication apparatus 120.
  • the second wireless communication apparatus 120 schedules data transmission to the first wireless communication apparatus 110 based on the channel state measurement value reported from the first wireless communication apparatus 110.
  • the first wireless communication apparatus 110 reports the measured value of the channel state and information indicating that the channel state is deteriorated to the second wireless communication apparatus 120.
  • the second wireless communication device 120 calculates a channel state that is deteriorated by a predetermined amount from the measured value of the channel state reported from the first wireless communication device 110, and performs the first wireless communication based on the calculated channel state. Schedule transmission of data to the device 110.
  • the second wireless communication apparatus 120 can perform scheduling of data transmission to the first wireless communication apparatus 110 by predicting deterioration of the channel state. For this reason, it can suppress that the communication quality of the data transmission from the 2nd radio
  • the first wireless communication apparatus 110 may report information indicating whether or not the channel state is deteriorated to the second wireless communication apparatus 120 by a report signal as information regarding the time change of the channel state.
  • first wireless communication apparatus 110 reports a measured value of the channel state and information indicating that the channel state has not deteriorated to second wireless communication apparatus 120.
  • the second wireless communication apparatus 120 schedules data transmission to the first wireless communication apparatus 110 based on the channel state measurement value reported from the first wireless communication apparatus 110.
  • the first wireless communication apparatus 110 reports the measured value of the channel state and information indicating that the channel state is deteriorated to the second wireless communication apparatus 120.
  • the second wireless communication device 120 calculates a channel state that is deteriorated by a predetermined amount from the measured value of the channel state reported from the first wireless communication device 110, and performs the first wireless communication based on the calculated channel state. Schedule transmission of data to the device 110.
  • the second wireless communication apparatus 120 can perform scheduling of data transmission to the first wireless communication apparatus 110 by predicting deterioration of the channel state. For this reason, it can suppress that the communication quality of the data transmission from the 2nd radio
  • the information regarding the time change of the channel state reported by the report signal may be a channel state measurement obtained by a measurement prior to the latest measurement of the channel state reported by the report signal. . That is, the first wireless communication apparatus 110 transmits a report signal including the latest measurement value of the channel state and the measurement value of the channel state obtained by the measurement before the measurement value to the second wireless communication apparatus 120. You may send it.
  • the second wireless communication device 120 predicts a change in the channel state based on the latest measurement value and the past measurement value of the channel state, and the first wireless communication device based on the predicted change in the channel state.
  • the data transmission to 110 is scheduled.
  • the second wireless communication device 120 when the latest measured value is not worse than the past measured value, the second wireless communication device 120 performs scheduling based on the reported latest measured value. In addition, when the latest measured value is worse than the past measured value, the second wireless communication apparatus 120 calculates a channel state that is deteriorated by a predetermined amount from the reported latest measured value, and calculates the calculated channel state. Scheduling based on Second radio communication apparatus 120 estimates the slope of the channel state change from the latest measurement value and the channel state measurement value obtained by the measurement prior to the measurement value, and uses the channel for scheduling The state may be calculated.
  • the information related to the time change of the channel state reported by the report signal may be information that allows the second wireless communication apparatus 120 to identify the CSI change amount.
  • TDD is an abbreviation for Time Division Duplex.
  • the first wireless communication device 110 uses the report signal to indicate the amount of interference (may include noise) in the first wireless communication device 110 and the amount of change in the amount of interference in the first wireless communication device 110 as the second. You may report to the wireless communication apparatus 120.
  • Second radio communication apparatus 120 measures the signal power of the reference signal transmitted from first radio communication apparatus 110.
  • the second wireless communication apparatus 120 then transmits data from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 based on the measured value of the signal power and the amount of interference reported from the first wireless communication apparatus 110.
  • SINR signal to interference and noise power ratio
  • the second wireless communication device 120 transmits the first wireless signal from the second wireless communication device 120 based on the amount of change in the measured value of the signal power and the amount of change in the interference amount reported from the first wireless communication device 110.
  • the amount of change in SINR in data transmission to the communication device 110 can be calculated.
  • the information related to the time change of the channel state reported by the report signal may be information indicating the moving speed of the first wireless communication apparatus 110.
  • the channel state CSI, for example, CQI
  • the first wireless communication device 110 transmits a report signal including a CSI measurement value and information indicating the moving speed of the first wireless communication device 110 to the second wireless communication device 120.
  • the second wireless communication apparatus 120 performs scheduling based on the latest measured value reported. Do.
  • the second wireless communication apparatus 120 calculates a channel state that is deteriorated by a predetermined amount from the latest reported measurement value. Then, scheduling is performed based on the calculated channel state.
  • the first wireless communication apparatus 110 receives a report signal including the CSI measurement value and information indicating whether or not the moving speed of the first wireless communication apparatus 110 exceeds a predetermined speed. May be sent to.
  • the predetermined speed is a speed of 0 or more. For example, when the predetermined speed is 0, the information indicating whether or not the moving speed of the first wireless communication device 110 exceeds the predetermined speed is information indicating whether or not the first wireless communication device 110 is moving. .
  • the second wireless communication device 120 performs scheduling based on the latest reported measurement value. I do.
  • the second wireless communication device 120 changes the channel state that is deteriorated by a predetermined amount from the reported latest measured value. The scheduling is performed based on the calculated channel state.
  • FIG. 12 is a diagram of an example of a channel state report by the first wireless communication apparatus according to the second embodiment.
  • the same parts as those shown in FIG. 12 are identical parts as those shown in FIG. 12;
  • CSI (-1) is CSI measured by the first wireless communication apparatus 110 at time T (-1).
  • CSI (0) is CSI measured by first radio communication apparatus 110 at time T (0).
  • CSI (3) is CSI measured by first radio communication apparatus 110 at time T (3).
  • CSI (4) is CSI measured by first radio communication apparatus 110 at time T (4).
  • the first wireless communication device 110 transmits the measured value a0 and the change amount a1 based on CSI ( ⁇ 1) and CSI (0) to the second wireless communication device 120 at time T (1) immediately after time T (0). Report.
  • the first wireless communication apparatus 110 is obtained by subtracting the margin ⁇ from the slope a1 obtained by dividing the difference between CSI ( ⁇ 1) and CSI (0) by the time interval T as the change amount a1. It is assumed that the inclination a1 ′ is reported to the second wireless communication apparatus 120.
  • the first wireless communication device 110 reports the measured value a0 and the change amount a1 reported to the second wireless communication device 120 at time T (1), the measured value of CSI in its own device, and Compare the amount of change. Then, when the amount of change based on the measured value of CSI in the own device is lower (deteriorated) than the amount of change a1 reported to the second wireless communication device 120, the first wireless communication device 110 obtains the latest measured value and amount of change. Report to second radio communication apparatus 120.
  • the CSI measurement result 1211 shown in FIG. 12 is a CSI measurement result by the first wireless communication apparatus 110 in each time interval including a time interval after the time T (1).
  • the slope b1 obtained by subtracting the margin ⁇ from the slope b1 obtained by dividing the difference between CSI (3) and CSI (4) by the time interval T has been reported to the second radio communication apparatus 120.
  • the inclination is lower than a1 ′ (b1 ⁇ a1 ′).
  • the first wireless communication device 110 reports the latest CSI measurement value b0 and change amount b1 'to the second wireless communication device 120 when the change amount of CSI is worse than the reported change amount.
  • the change amount of CSI is worse than the reported change amount, it is possible to suppress the communication quality of data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 from being lower than the reference value. it can.
  • FIG. 13 is a flowchart of an example of processing by the first wireless communication apparatus according to the second embodiment.
  • the first wireless communication apparatus 110 according to the second embodiment executes, for example, each step illustrated in FIG. Steps S1301 and S1302 shown in FIG. 13 are the same as steps S301 and S302 shown in FIG.
  • first wireless communication apparatus 110 determines whether or not the change amount of CSI based on the latest measurement value of CSI is worse than the change amount of CSI that has been reported to second wireless communication apparatus 120 in the past. Is determined (step S1303).
  • step S1303 when it has not deteriorated (step S1303: No), the 1st radio
  • step S1303: Yes the 1st radio
  • the process proceeds to step S1305.
  • Steps S1305 and S1306 shown in FIG. 13 are the same as steps S303 and S304 shown in FIG.
  • the first wireless communication apparatus 110 adds, for example, the CSI measurement value and change amount to the periodic report timing, and the latest CSI change amount is greater than the reported CSI change amount. You may report to the 2nd radio
  • FIG. 14 is a flowchart of an example of processing by the second wireless communication apparatus according to the second embodiment.
  • the second wireless communication apparatus 120 according to the second embodiment executes, for example, each step illustrated in FIG. Steps S1401 and S1402 shown in FIG. 14 are the same as steps S401 and S402 shown in FIG.
  • the second wireless communication apparatus 120 receives a report signal indicating the latest measured value of CSI and the amount of change in CSI from the first wireless communication apparatus 110 at a non-periodic timing.
  • the report signal is received (step S1403).
  • This report signal is, for example, the report signal transmitted in step S1304 shown in FIG.
  • step S1404 the second wireless communication apparatus 120 uses the measurement value of the channel state and the change amount of the channel state included in the latest report signal among the report signals received in steps S1402 and S1403 to determine the future time Calculate the CSI at the resource.
  • the second wireless communication apparatus 120 transmits, for example, a report signal indicating the measured value and change amount of CSI from the first wireless communication apparatus 110 at a non-periodic timing in addition to the periodic reporting timing. You may receive it.
  • the first wireless communication device 110 when the rate of temporal change in the channel state measurement value is worse than the rate reported to the second wireless communication device 120, The latest report signal is transmitted to the second wireless communication apparatus 120. Thereby, it is possible to report when the rate of change in channel state is worse than the rate of change already reported. For this reason, even if the frequency of reports from the first wireless communication apparatus 110 to the second wireless communication apparatus 120 is low, the communication quality of data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 has the reference value. It is possible to suppress lowering.
  • Embodiment 3 The third embodiment will be described with respect to differences from the first and second embodiments.
  • a configuration in which first radio communication apparatus 110 transmits a report signal to second radio communication apparatus 120 at a non-periodic timing will be described.
  • FIG. 15 is a diagram of an example of a channel state report by the first wireless communication apparatus according to the third embodiment. In FIG. 15, the same parts as those shown in FIG.
  • the first wireless communication device 110 at time T (1) immediately after time T (0), CSI measurement value a0 at time T (0) and before time T (0).
  • the CSI change amount a1 based on the CSI measurement value is reported to the second wireless communication apparatus 120.
  • the predicted CSI characteristic 1511 indicates the CSI in each time interval predicted by the measured value a0 (intercept) and the change amount a1 (slope) that the first wireless communication apparatus 110 reports to the second wireless communication apparatus 120 at time T (1). It is.
  • the first wireless communication apparatus 110 determines whether or not the measured CSI value after the time T (1) when the measured value a0 and the change amount a1 are reported is worse than the CSI predicted by the predicted CSI characteristic 1511. Then, when the measured value of CSI becomes worse than the CSI predicted by predicted CSI characteristic 1511, first wireless communication device 110 reports the latest measured value a0 and change amount a1 to second wireless communication device 120.
  • the CSI measurement result 1521 shown in FIG. 15 is a CSI measurement result by the first wireless communication apparatus 110 in each time interval including a time interval after the time T (1).
  • the CSI measured by the first wireless communication apparatus 110 at time T (4) is lower than the estimated CSI value at time T (4) based on the predicted CSI characteristic 1511.
  • first wireless communication apparatus 110 reports CSI measured at time T (4) as measurement value a0 at time T (5) immediately after time T (4).
  • the first wireless communication device 110 reports, to the second wireless communication device 120, a change amount based on CSI measured at the latest time including the time T (4) as the change amount a1 at the time T (5). .
  • the first wireless communication device 110 when the CSI measurement value is worse than the CSI predicted based on the reported measurement value a0 and change amount a1, the latest CSI measurement value a0 and change amount a1. To the second wireless communication apparatus 120. As a result, even if the CSI measurement value is worse than the CSI predicted based on the reported measurement value a0 and change amount a1, the data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 It can suppress that communication quality falls below a reference value.
  • FIG. 16 is a flowchart of an example of processing by the first wireless communication apparatus according to the third embodiment.
  • the first wireless communication apparatus 110 according to the third embodiment executes the steps shown in FIG. 16, for example. Steps S1601 and S1602 shown in FIG. 16 are the same as steps S301 and S302 shown in FIG.
  • the first wireless communication apparatus 110 determines whether the latest measured value of CSI is worse than the estimated value based on the measured value and change amount of CSI reported to the second wireless communication apparatus 120 in the past. It is determined whether or not (step S1603).
  • step S1603 when it has not deteriorated (step S1603: No), the 1st radio
  • step S1603: Yes the 1st radio
  • the process proceeds to step S1605.
  • Steps S1605 and S1606 shown in FIG. 16 are the same as steps S303 and S304 shown in FIG.
  • the first wireless communication apparatus 110 adds, for example, the CSI measurement value and the change amount to the periodic report timing, and the latest CSI measurement value is based on the reported information.
  • the first wireless communication device 110 does not report the CSI measurement value and change amount to the second wireless communication device 120 once, but does not report it at the periodic report timing, and the latest CSI measurement value. May be reported at a timing worse than the estimated value based on the reported information.
  • the processing by the second wireless communication apparatus 120 according to the third embodiment is the same as, for example, each step shown in FIG.
  • the first wireless communication device 110 may predict that the CSI measurement value is worse than the CSI predicted based on the reported measurement value a0 and the change amount a1. For example, when the first wireless communication device 110 reports the measurement value a0 and the change amount a1 to the second wireless communication device 120, the estimated value of CSI based on the reported measurement value a0 and the change amount a1 and the CSI of the own device. The difference between the measured value and the measured value is calculated periodically (for example, every subframe).
  • the latest CSI measurement value a0 and the change amount a1 are set to the second radio. It is possible to report to the communication device 120.
  • the first wireless communication apparatus 110 predicts that the measured value of CSI is worse than the CSI predicted based on the reported measured value a0 and the change amount a1 at time T (3), and the latest CSI
  • the measurement value a0 and the change amount a1 can be reported to the second wireless communication apparatus 120.
  • the change amount a1 can be reported to the second wireless communication apparatus 120. For this reason, it can suppress that the communication quality of the data transmission from the 2nd radio
  • the first wireless communication apparatus 110 calculates the difference between the measured value of CSI and the estimated value of CSI calculated using the measured value of CSI and the amount of change included in the transmitted report signal. Based on the calculated temporal change amount of the difference, it can be predicted that the measured value of CSI is worse than the estimated value of CSI.
  • the first wireless communication apparatus 110 calculates the measured value of the channel state at a certain time using the measured value and change amount of the CSI included in the transmitted report signal.
  • the latest report signal is transmitted to the second wireless communication apparatus 120 when the estimated value of the channel state at that time has deteriorated. Thereby, it is possible to report when the measured value of the channel state is worse than the channel state predicted from the reported information. For this reason, even if the frequency of reports from the first wireless communication apparatus 110 to the second wireless communication apparatus 120 is low, the communication quality of data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 has the reference value. It is possible to suppress lowering.
  • the first wireless communication apparatus 110 uses the measured value of the channel state at a certain time and the estimated value of the channel state at that time calculated using the measured value and change amount of the CSI included in the transmitted report signal.
  • the latest report signal is transmitted to the second wireless communication apparatus 120.
  • the first wireless communication apparatus 110 calculates the difference between the measured value of the channel state and the estimated value of the channel state calculated using the measured value and change amount of the CSI included in the transmitted report signal.
  • the prediction can be performed based on the calculated change amount of the difference. Thereby, it can report before the measured value of a channel state deteriorates from the channel state estimated from reported information. For this reason, even if the frequency of reports from the first wireless communication apparatus 110 to the second wireless communication apparatus 120 is low, the communication quality of data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 has the reference value. It is possible to suppress lowering.
  • the first wireless communication device 110 may calculate the error rate based on a response signal (ACK / NACK) generated based on the decoding result of the data received from the second wireless communication device 120. Then, the first wireless communication device 110 may transmit a report signal based on the latest measured CSI value to the second wireless communication device 120 when the calculated error rate exceeds the reference value.
  • ACK / NACK response signal
  • first wireless communication apparatus 110 transmits information on the time change of the channel state to the second wireless communication apparatus 120 in addition to the measurement value of the channel state and the information on the time change of the channel state.
  • the configuration to be reported will be described.
  • FIG. 17 is a diagram illustrating an example of calculation of the change amount of the CSI change amount by the first wireless communication apparatus according to the fourth embodiment. 17, parts that are the same as the parts shown in FIG. 8 are given the same reference numerals, and descriptions thereof will be omitted.
  • CSI ( ⁇ 2) is CSI measured by the first wireless communication apparatus 110 at time T ( ⁇ 2).
  • CSI ( ⁇ 1) is CSI measured by first radio communication apparatus 110 at time T ( ⁇ 1).
  • CSI (0) is CSI measured by first radio communication apparatus 110 at time T (0).
  • the estimated value CSI (t) of the CSI at a future time t can be approximated by the following equation (1), for example.
  • the first wireless communication device 110 solves the following simultaneous equation (2), for example.
  • the first wireless communication apparatus 110 obtains the intercept a0, the first-order coefficient a1 (slope or change amount) and the second-order coefficient a2 (slope of inclination or change amount of change) shown in the following equation (3). Obtainable.
  • the first radio communication apparatus 110 reports the obtained intercept a0, the first-order coefficient a1, and the second-order coefficient a2 to the second radio communication apparatus 120 at time T (1) immediately after time T (0). .
  • the second wireless communication apparatus 120 uses the intercepts a0 and 1 reported from the first wireless communication apparatus 110 to estimate the CSI between the second wireless communication apparatus 120 and the first wireless communication apparatus 110 at a future time t. It calculates based on the following coefficient a1 and secondary coefficient a2, and said (1) Formula.
  • the approximate curve 1711 is CSI in each time interval predicted by the intercept a0, the first-order coefficient a1 and the second-order coefficient a2, and the above equation (1).
  • Second wireless communication device 120 calculates an estimated value of CSI between second wireless communication device 120 and first wireless communication device 110 at time t based on approximate curve 1711.
  • the CSI measurement value by the first wireless communication device 110 may be worse than the CSI predicted by the approximate curve 1711.
  • the first wireless communication apparatus 110 may report to the second wireless communication apparatus 120 by including a margin in at least one of the primary coefficient a1 and the secondary coefficient a2.
  • the second wireless communication device 120 may determine that the first-order coefficient a1 ′ and the second-order coefficient a2 ′ are based on the intercept a0, the first-order coefficient a1, and the second-order coefficient a2 reported from the first wireless communication apparatus 110. May be calculated.
  • first radio communication apparatus 110 includes a channel state measurement value, information on a channel state time change, and information on a channel state time change time change.
  • a report signal is transmitted to the second wireless communication apparatus 120.
  • the second-order coefficient a2 has been described in the above example, but it is not limited to such a configuration.
  • the information regarding the time change of the channel state time change is information indicating whether or not a value indicating the time change of the channel state (for example, the first-order coefficient a1) is temporally changing (for example, worsening). Also good.
  • the second wireless communication device 120 for example, if the first wireless communication device 110 reports that the value indicating the time change of the channel state has not changed in time, Scheduling is performed based on the channel state calculated from the measured value and the amount of change. In addition, when the first wireless communication device 110 reports that the value indicating the time change of the channel state is changing with time, the second wireless communication device 120 reports the latest measured value and change. A channel state that is deteriorated by a predetermined amount from the channel state calculated from the amount is calculated. Then, the second wireless communication device 120 performs scheduling based on the calculated channel state.
  • the channel state is badly estimated and scheduling is performed, and the communication quality of data transmission from the second wireless communication apparatus 120 to the first wireless communication apparatus 110 is the reference value. Can be suppressed.
  • FIG. 18 is a diagram of an example of channel state estimation performed by the second wireless communication apparatus according to the fifth embodiment.
  • the channel state 1801 calculated from the reported measurement value and the amount of change is less than the worst value 1802 of the actual channel state value. It can be quite bad.
  • the worst value 1803 of the channel state in the past predetermined period may be included in the report information transmitted and received in S302, S402, S1302, S1402, and S1602.
  • the worst value 1803 measured at time T ( ⁇ 6) is included in the report at time T ( ⁇ 3). Then, when the calculated channel state 1801 becomes worse than the worst value 1803, the second wireless communication apparatus 120 may perform the scheduling by replacing the calculated channel state 1801 with the worst value 1803. .
  • the example in which the first wireless communication device 110 is applied to a wireless terminal and the second wireless communication device 120 is applied to a wireless base station has been described.
  • the first wireless communication device 110 and the second wireless communication device are described.
  • the application destination of the communication device 120 is not limited to these.
  • the second wireless communication device 120 may be a wireless terminal that performs terminal-to-terminal communication with the first wireless communication device 110.
  • the first wireless communication device 110 and the second wireless communication device 120 may be provided in different vehicles, and wireless communication between the vehicles may be realized.
  • the requirements for automobile communication require high reliability such as an error rate of 10 ⁇ 5 and low delay.
  • the error rate in data transmission is reduced, thereby reducing the delay associated with retransmission and realizing high reliability and low delay. be able to.
  • the second wireless communication device 120 calculates the relative speed between the first wireless communication device 110 and the own device based on the moving speed of the first wireless communication device 110 and the moving speed of the own device. . Then, the second wireless communication device 120 converts the calculated relative speed into a rate of change in channel state over time, and estimates a future channel state based on the converted rate.
  • wireless communication between vehicles is not limited to wireless communication associated with automatic driving of a vehicle, and may be wireless communication that transmits information such as traffic jam information and brake information to assist driving by a driver.
  • the wireless communication device As described above, according to the wireless communication device, the wireless communication system, and the wireless communication method, it is possible to reduce the error rate in data transmission.
  • URLLC is an investigation theme for applications such as automatic driving and remote control.
  • URLLC is an abbreviation for Ultra-Reliable and Low Latency Communications.
  • a packet error rate of 10 ⁇ 5 in one transmission is required.
  • link adaptation including CSI reporting and outer loop control is known in conventional technologies such as LTE.
  • the CSI reports in link adaptation include periodic reports and aperiodic reports.
  • the periodic report of LTE it is possible to report a period of 2 [ms] at the shortest.
  • the feedback amount per time is small.
  • the non-periodic report a report is made in response to a request from the network, and the amount of information that can be reported is larger than the periodic report.
  • the correction amount (margin) of CSI when converting from CSI to MCS is adjusted.
  • the error rate is, for example, BLER (BLOCK Error Ratio: block error rate).
  • the channel state may have already fluctuated (deteriorated), and the target error rate may not be obtained. For this reason, in high-reliability communication such as URLLC, the target BLER is small, so there are cases where the margin update by outer loop control is not in time.
  • the data receiving side when the data receiving side reports CSI, in addition to the measured value of CSI, it reports information on channel time variation. In this way, by reporting not only the current (latest) channel state but also information on channel fluctuations, the channel state can be corrected over time, and there are channel fluctuations. Even in this case, a desired error rate can be satisfied.
  • URLLC is expected to be used in an environment with a relatively good channel state by using diversity technology or the like in order to increase reliability. For this reason, it is highly likely that the variation (ratio) of the channel state also becomes moderate. For this reason, it can be expected that the reporting frequency can be reduced by reporting information (for example, the amount of change) regarding the channel state temporal variation.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un premier dispositif de communication sans fil (110) reçoit des données provenant d'un deuxième dispositif de communication sans fil (120). En outre, le premier dispositif de communication sans fil (110) mesure un état de canal dans le premier dispositif de communication sans fil, et transmet des signaux au deuxième dispositif de communication sans fil (120), lesdits signaux contenant la valeur de mesure de l'état de canal, et des informations concernant un changement d'état de canal dans le temps. En fonction des signaux reçus en provenance du premier dispositif de communication sans fil (110), le deuxième dispositif de communication sans fil (120) calcule une valeur d'estimation d'un état de canal entre le deuxième dispositif de communication sans fil et le premier dispositif de communication sans fil (110). En outre, en fonction de la valeur d'estimation ainsi calculée, le deuxième dispositif de communication sans fil (120) réalise l'ordonnancement de transmission de données au premier dispositif de communication sans fil (110).
PCT/JP2016/078957 2016-09-29 2016-09-29 Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil WO2018061168A1 (fr)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020017043A1 (fr) * 2018-07-20 2020-01-23 株式会社Ｎｔｔドコモ Terminal d'utilisateur et station de base
CN114402560A (zh) * 2019-09-19 2022-04-26 高通股份有限公司 用于确定信道状态信息的系统和方法
WO2024034066A1 (fr) * 2022-08-10 2024-02-15 株式会社Ｎｔｔドコモ Terminal, procédé de communication sans fil et station de base
WO2024034065A1 (fr) * 2022-08-10 2024-02-15 株式会社Ｎｔｔドコモ Terminal, procédé de communication sans fil et station de base

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Publication number Priority date Publication date Assignee Title
JP2008288812A (ja) * 2007-05-16 2008-11-27 Mitsubishi Electric Corp 回線品質報告方法、基地局、移動局および通信システム
JP2010114517A (ja) * 2008-11-04 2010-05-20 Ntt Docomo Inc 移動端末装置及び無線基地局装置
WO2013088710A1 (fr) * 2011-12-12 2013-06-20 京セラ株式会社 Station de base, système de communication et procédé de communication
WO2014181431A1 (fr) * 2013-05-09 2014-11-13 富士通株式会社 Dispositif de station mobile, dispositif de station de base et procédé de communication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008288812A (ja) * 2007-05-16 2008-11-27 Mitsubishi Electric Corp 回線品質報告方法、基地局、移動局および通信システム
JP2010114517A (ja) * 2008-11-04 2010-05-20 Ntt Docomo Inc 移動端末装置及び無線基地局装置
WO2013088710A1 (fr) * 2011-12-12 2013-06-20 京セラ株式会社 Station de base, système de communication et procédé de communication
WO2014181431A1 (fr) * 2013-05-09 2014-11-13 富士通株式会社 Dispositif de station mobile, dispositif de station de base et procédé de communication

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020017043A1 (fr) * 2018-07-20 2020-01-23 株式会社Ｎｔｔドコモ Terminal d'utilisateur et station de base
CN114402560A (zh) * 2019-09-19 2022-04-26 高通股份有限公司 用于确定信道状态信息的系统和方法
WO2024034066A1 (fr) * 2022-08-10 2024-02-15 株式会社Ｎｔｔドコモ Terminal, procédé de communication sans fil et station de base
WO2024034065A1 (fr) * 2022-08-10 2024-02-15 株式会社Ｎｔｔドコモ Terminal, procédé de communication sans fil et station de base

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