WO2016021033A1 - Appareil de terminal mobile - Google Patents

Appareil de terminal mobile Download PDF

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Publication number
WO2016021033A1
WO2016021033A1 PCT/JP2014/070953 JP2014070953W WO2016021033A1 WO 2016021033 A1 WO2016021033 A1 WO 2016021033A1 JP 2014070953 W JP2014070953 W JP 2014070953W WO 2016021033 A1 WO2016021033 A1 WO 2016021033A1
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WO
WIPO (PCT)
Prior art keywords
mobile terminal
adjustment
base station
unit
transmission timing
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Application number
PCT/JP2014/070953
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English (en)
Japanese (ja)
Inventor
誠二 濱田
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富士通株式会社
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Publication date
Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to PCT/JP2014/070953 priority Critical patent/WO2016021033A1/fr
Publication of WO2016021033A1 publication Critical patent/WO2016021033A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements

Definitions

  • the present invention relates to a mobile terminal device.
  • wireless communication systems such as LTE (Long Term Evolution) are known.
  • LTE Long Term Evolution
  • TA Triming Advance
  • timing is updated (for example, see Patent Document 1 below).
  • Patent Document 2 a technique for sharing intermittent parameters between a wireless terminal and a wireless base station without using a wireless communication path is known (for example, see Patent Document 2 below).
  • the above-described conventional technique has a problem in that, for example, when the variation in the transmission timing deviation of the mobile terminal is large, the base station increases the number of transmissions of a signal that instructs the mobile terminal to adjust the transmission timing.
  • the conventional mobile terminal described above has a problem that the uplink transmission timing cannot be adjusted in a period in which a signal instructing adjustment of the uplink transmission timing is not received from the base station.
  • the present invention provides a mobile terminal device capable of adjusting uplink transmission timing at a timing different from the reception timing of a signal from a base station that instructs adjustment of uplink transmission timing. Objective.
  • an instruction signal for transmitting a radio signal to a base station apparatus and instructing adjustment of a transmission timing of the radio signal is transmitted to the base station apparatus.
  • the adjustment value according to the received instruction signal is stored, and the first adjustment of the transmission timing according to the received instruction signal is the second adjustment at a time different from the first adjustment.
  • a mobile terminal device that performs the second adjustment of the transmission timing based on the stored adjustment value is proposed.
  • the uplink transmission timing can be adjusted at a timing different from the reception timing of the signal from the base station instructing the adjustment of the uplink transmission timing.
  • FIG. 1A is a diagram illustrating an example of the wireless communication system according to the first embodiment.
  • 1B is a diagram illustrating an example of a signal flow in the wireless communication system illustrated in FIG. 1A.
  • FIG. 2 is a diagram of an example of the communication system according to the second embodiment.
  • FIG. 3 is a diagram illustrating an example of transmission timing control between the radio base station and the mobile terminal.
  • FIG. 4A is a diagram of an example of a base station according to the second embodiment.
  • 4B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 4A.
  • FIG. 5 is a diagram illustrating an example of CP insertion processing.
  • FIG. 6A is a diagram illustrating an example of a timing detection unit.
  • FIG. 6B is a diagram illustrating an example of a signal flow in the timing detection unit illustrated in FIG. 6A.
  • FIG. 7 is a diagram illustrating an example of a delay profile.
  • FIG. 8A is a diagram illustrating an example of a mobile terminal according to the second embodiment.
  • FIG. 8B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 8A.
  • FIG. 9A is a flowchart (part 1) illustrating an example of a process performed by the mobile terminal according to the second embodiment.
  • FIG. 9B is a flowchart (part 2) illustrating an example of processing by the mobile terminal according to the second embodiment.
  • FIG. 10 is a flowchart of a modification of the process performed by the mobile terminal according to the second embodiment.
  • FIG. 11A is a diagram (part 1) illustrating an example of a moving speed and a correction interval of a mobile terminal.
  • FIG. 11B is a diagram (part 2) illustrating an example of the moving speed and the correction interval of the mobile terminal.
  • FIG. 12A is a diagram (part 1) illustrating an example of a TA command accumulated value and a correction interval.
  • FIG. 12B is a diagram (part 2) illustrating an example of the TA command accumulated value and the correction interval.
  • FIG. 13A is a diagram illustrating an example of a mobile terminal according to the third embodiment.
  • FIG. 13B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 13A.
  • FIG. 14 is a flowchart of an example of processing performed by the mobile terminal according to the third embodiment.
  • FIG. 15A is a diagram of an example of a base station according to the fourth embodiment.
  • FIG. 15B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 15A.
  • FIG. 16A is a diagram illustrating an example of a mobile terminal according to the fourth embodiment.
  • FIG. 16B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 16A.
  • FIG. 17A is a flowchart (part 1) illustrating an example of processing by the base station according to the fourth embodiment.
  • FIG. 17B is a flowchart (part 2) illustrating an example of processing by the base station according to the fourth embodiment.
  • FIG. 18 is a flowchart of a modification of the process performed by the base station according to the fourth embodiment.
  • FIG. 1 is a diagram of an example of a base station according to the fourth embodiment.
  • FIG. 15B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 15A.
  • FIG. 19 is a flowchart of an example of processing performed by the mobile terminal according to the fourth embodiment.
  • FIG. 20A is a diagram of an example of a base station according to the fifth embodiment.
  • 20B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 20A.
  • FIG. 21 is a flowchart of an example of processing by the base station according to the fifth embodiment.
  • FIG. 22A is a diagram of an example of a base station according to the sixth embodiment.
  • 22B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 22A.
  • FIG. 23 is a flowchart of an example of processing by the base station according to the sixth embodiment.
  • FIG. 1A is a diagram illustrating an example of the wireless communication system according to the first embodiment.
  • 1B is a diagram illustrating an example of a signal flow in the wireless communication system illustrated in FIG. 1A.
  • the wireless communication system 100 according to the first embodiment includes a mobile terminal device 110 and a base station device 120.
  • the mobile terminal device 110 includes a transmission unit 111, a reception unit 112, a storage unit 113, and an adjustment unit 114.
  • Transmitting section 111 transmits a radio signal to base station apparatus 120.
  • the radio signal transmitted by the transmitter 111 is, for example, a data signal or a control signal from the mobile terminal apparatus 110 to the base station apparatus 120.
  • the transmission unit 111 transmits a radio signal at the transmission timing adjusted by the adjustment unit 114.
  • the receiving unit 112 receives an instruction signal for instructing adjustment of the transmission timing of the radio signal by the transmitting unit 111 from the base station apparatus 120.
  • the instruction signal received by the reception unit 112 may include information indicating a shift in the transmission timing of the radio signal by the transmission unit 111 with respect to the reference timing of the base station device 120.
  • the instruction signal received by the receiving unit 112 is, for example, a TA command.
  • the receiving unit 112 outputs the received instruction signal to the storage unit 113 and the adjustment unit 114.
  • the storage unit 113 stores an adjustment value corresponding to the instruction signal output from the reception unit 112.
  • the adjustment unit 114 performs the first adjustment of the transmission timing of the transmission unit 111 according to the instruction signal output from the reception unit 112.
  • the first adjustment of the transmission timing is performed each time the mobile terminal apparatus 110 receives an instruction signal from the base station apparatus 120, for example.
  • the adjustment unit 114 is a second adjustment at a time different from the first adjustment of the transmission timing, and performs the second adjustment of the transmission timing of the transmission unit 111 based on the adjustment value stored in the storage unit 113. Do. That is, the second adjustment of the transmission timing is an adjustment performed separately from the first adjustment of the transmission timing performed each time the mobile terminal apparatus 110 receives the instruction signal, for example.
  • the adjustment value stored in the storage unit 113 used in the second adjustment of the transmission timing corresponds to the adjustment value used in the past in the first adjustment of the transmission timing.
  • the adjustment unit 114 performs the second adjustment of the transmission timing based on, for example, the adjustment value used by the mobile terminal device 110 in the most recent first adjustment among the adjustment values stored in the storage unit 113. Also good. Also in this case, the uplink transmission timing can be adjusted with high accuracy, for example, when the change in the deviation of the uplink transmission timing is constant.
  • the base station device 120 Based on the radio signal received from the mobile terminal device 110, the base station device 120 detects a shift in radio signal transmission timing by the mobile terminal device 110 with respect to the reference timing of the base station device 120. Then, the base station apparatus 120 transmits an instruction signal including information indicating the detected deviation and instructing the mobile terminal apparatus 110 to adjust the transmission timing to the mobile terminal apparatus 110.
  • mobile terminal apparatus 110 adjusts according to an instruction signal received in the past, separately from the first adjustment of transmission timing according to the instruction signal from base station apparatus 120.
  • the second adjustment of the autonomous transmission timing using the value can be performed.
  • the mobile terminal apparatus 110 can adjust the uplink transmission timing at a timing different from the reception timing of the signal from the base station apparatus 120 instructing the adjustment of the uplink transmission timing.
  • the base station apparatus 120 reduces the number of transmissions of a signal instructing adjustment of transmission timing to the mobile terminal apparatus 110 or suppresses an increase in the number of transmissions while maintaining and improving uplink transmission timing accuracy. Is possible.
  • the instruction signal transmitted by the base station apparatus 120 includes an instruction signal transmitted periodically.
  • the mobile terminal apparatus 110 performs the second adjustment of the autonomous transmission timing, thereby enabling the base station apparatus 120 to set a longer transmission period of the instruction signal. Become.
  • the instruction signal transmitted by the base station apparatus 120 may include an instruction signal transmitted in accordance with a radio signal transmission timing shift by the mobile terminal apparatus 110.
  • the mobile terminal apparatus 110 performs the second adjustment of the autonomous transmission timing, thereby shifting the transmission timing of the radio signal by the mobile terminal apparatus 110.
  • the base station apparatus 120 can reduce or reduce an increase in the number of transmissions of the instruction signal according to a shift in transmission timing with respect to the mobile terminal apparatus 110 while maintaining and improving uplink transmission timing accuracy. it can.
  • the adjustment unit 114 estimates a change in radio signal transmission timing shift by the mobile terminal apparatus 110 based on each adjustment value corresponding to a plurality of instruction signals stored in the storage unit 113. And the adjustment part 114 performs the 2nd adjustment of a transmission timing based on the estimation result of the change of the transmission timing shift
  • the second adjustment of the transmission timing by the adjustment unit 114 may be an adjustment based on a period based on the moving speed of the mobile terminal device 110 (own device).
  • the second adjustment of the transmission timing by the adjustment unit 114 can be an adjustment with a shorter period as the moving speed of the mobile terminal device 110 is higher.
  • the control of the second adjustment cycle of the mobile terminal device 110 based on the moving speed of the mobile terminal device 110 may be performed by the mobile terminal device 110 or the base station device 120.
  • the second adjustment of the transmission timing by the adjustment unit 114 is an adjustment based on a period based on the accumulated result of the transmission timing shift of the mobile terminal apparatus 110 indicated by the instruction signal transmitted from the base station apparatus 120 to the mobile terminal apparatus 110. It is good.
  • the second adjustment of the transmission timing by the adjustment unit 114 can be an adjustment with a shorter period as the accumulated result of the transmission timing shift of the mobile terminal apparatus 110 is larger.
  • the control of the second adjustment cycle of the mobile terminal device 110 based on the accumulated transmission timing deviation of the mobile terminal device 110 may be performed by the mobile terminal device 110 or the base station device 120. Good.
  • the second adjustment of the transmission timing by the adjustment unit 114 is started or stopped based on the cumulative result of the transmission timing shift of the mobile terminal device 110 indicated by the instruction signal transmitted from the base station device 120 to the mobile terminal device 110. be able to.
  • the second adjustment of the transmission timing by the adjustment unit 114 is started when the cumulative result of the transmission timing shift of the mobile terminal device 110 in the latest predetermined period exceeds a predetermined value.
  • an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the second adjustment of the transmission timing by the adjustment unit 114 is that the accumulated result of the transmission timing deviation of the mobile terminal device 110 in the most recent predetermined period after the second adjustment is started has a predetermined value. Stopped if exceeded. As a result, the autonomous adjustment can be stopped when the variation of the transmission timing cannot be suppressed even if the second adjustment is performed.
  • the second adjustment of the transmission timing by the adjustment unit 114 is the latest period, and the period until the cumulative result of the transmission timing shift of the mobile terminal apparatus 110 exceeds a predetermined value is shorter than the predetermined time. It may be started in some cases. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the second adjustment of the transmission timing is the most recent period after the second adjustment is started, and the magnitude of the cumulative result of the transmission timing deviation of the mobile terminal device 110 exceeds a predetermined value.
  • the period may be stopped when the period is shorter than a predetermined time.
  • the autonomous adjustment can be stopped when the variation of the transmission timing cannot be suppressed even if the second adjustment is performed.
  • Control of the start or stop of the second adjustment of the mobile terminal apparatus 110 based on the accumulated result of the transmission timing shift of the mobile terminal apparatus 110 may be performed by the mobile terminal apparatus 110 or by the base station apparatus 120. May be.
  • the second adjustment of the transmission timing by adjustment unit 114 may be started or stopped based on the transmission frequency of the instruction signal by base station apparatus 120. For example, the second adjustment of the transmission timing by adjustment unit 114 is started when the transmission frequency of the instruction signal by base station apparatus 120 becomes higher than a predetermined frequency. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the second adjustment of the transmission timing by the adjustment unit 114 is stopped when the transmission frequency of the instruction signal by the base station apparatus 120 does not become lower than the predetermined frequency after the start of the second adjustment.
  • the case where the transmission frequency of the instruction signal does not become lower than the predetermined frequency after the start of the second adjustment is, for example, the case where fluctuations in the transmission timing deviation cannot be suppressed even if the second adjustment is performed. Therefore, after the start of the second adjustment, if the transmission frequency of the instruction signal by the base station apparatus 120 is not lower than the predetermined frequency, the second adjustment is stopped, so that the transmission timing is maintained even if the second adjustment is performed.
  • the second adjustment can be stopped when variation in deviation cannot be suppressed.
  • the second adjustment is continued even if the communication environment is improved and the variation in the transmission timing deviation becomes small, the transmission timing deviation occurs due to the second adjustment, and the transmission frequency of the instruction signal by the base station apparatus 120 Becomes higher. For this reason, even when the communication environment is improved and the variation of the transmission timing deviation becomes small, the transmission frequency of the instruction signal does not become lower than the predetermined frequency after the start of the second adjustment. Therefore, after the start of the second adjustment, if the transmission frequency of the instruction signal by the base station apparatus 120 is not lower than the predetermined frequency, the second adjustment is stopped, thereby suppressing the transmission timing deviation due to the second adjustment. be able to.
  • Control of the start or stop of the second adjustment of the mobile terminal device 110 based on the transmission frequency of the instruction signal by the base station device 120 may be performed by the mobile terminal device 110 or may be performed by the base station device 120. Good.
  • the second adjustment of the transmission timing by the adjusting unit 114 may be started or stopped based on the moving speed of the mobile terminal device 110.
  • the second adjustment of the transmission timing by the adjusting unit 114 is started when the moving speed of the mobile terminal device 110 becomes higher than a predetermined speed. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the second adjustment of the transmission timing by the adjustment unit 114 is stopped when the moving speed of the mobile terminal device 110 becomes lower than a predetermined speed after the start of the second adjustment. Thereby, autonomous adjustment can be stopped when the fluctuation
  • Control of starting or stopping the second adjustment of the mobile terminal device 110 based on the moving speed of the mobile terminal device 110 may be performed by the mobile terminal device 110 or the base station device 120.
  • the second adjustment of the transmission timing by the adjustment unit 114 may be started or stopped based on the number of mobile terminals accommodated in the base station apparatus 120.
  • the second adjustment of the transmission timing by the adjustment unit 114 is started when the number of mobile terminals accommodated in the base station apparatus 120 exceeds a predetermined number. Thereby, autonomous adjustment can be started when the throughput is reduced, and the throughput can be reduced.
  • the second adjustment of the transmission timing by the adjustment unit 114 is stopped when the number of mobile terminals accommodated in the base station apparatus 120 becomes smaller than a predetermined number after the start of the second adjustment.
  • the autonomous adjustment can be stopped, and the transmission timing of the mobile terminal apparatus 110 can be accurately adjusted by the instruction signal.
  • the base station apparatus 120 controls the start or stop of the second adjustment of the mobile terminal apparatus 110 based on the number of mobile terminals accommodated in the base station apparatus 120, for example. Further, the mobile terminal device 110 may control the second start or stop cycle of the mobile terminal device 110 based on the number of mobile terminals accommodated in the base station device 120. In this case, the mobile terminal apparatus 110 receives information indicating the number of mobile terminals accommodated in the base station apparatus 120 from the base station apparatus 120, for example.
  • FIG. 2 is a diagram of an example of the communication system according to the second embodiment.
  • the communication system 200 according to the second embodiment includes base stations 211 and 212 and mobile terminals 221 to 228.
  • the communication system 200 is a wireless communication system compatible with LTE, for example.
  • the mobile terminals 221 to 224 are located in the cell 211 a of the base station 211 and perform wireless communication with the base station 211.
  • the mobile terminals 225 to 228 are located in the cell 212 a of the base station 212 and perform wireless communication with the base station 212.
  • the base station 211 is connected to the core network 240 via the S1 interface 231.
  • the base station 212 is connected to the core network 240 via the S1 interface 232.
  • the base station 211 and the base station 212 are connected to each other via the X2 interface 250.
  • the mobile terminal apparatus 110 shown in FIGS. 1A and 1B can be applied to the mobile terminals 221 to 228, for example.
  • the base station apparatus 120 shown in FIGS. 1A and 1B can be applied to the base stations 211 and 212, for example.
  • the wireless communication system 100 shown in FIG. 1A and FIG. 1B has the transmission timing of the mobile terminal as used in LTE whose specifications are defined by 3GPP (3rd Generation Partnership Project). Can be applied to a communication system that adjusts the communication timing.
  • 3GPP 3rd Generation Partnership Project
  • the transmission timing of the mobile terminal is controlled for each mobile terminal. For this reason, the TA command is also transmitted for each mobile terminal.
  • the base station 211 monitors the uplink signal transmitted from the mobile terminal 221 in order to keep the reception timing of the uplink signal from the mobile terminal 221 constant, and the uplink signal from the mobile terminal 221 and the reference Monitor the deviation from the timing.
  • the base station 211 transmits a TA command instructing adjustment of transmission timing to the mobile terminal 221.
  • the mobile terminal 221 adjusts the transmission timing of the uplink signal from the mobile terminal 221 to the base station 211 based on the received TA command.
  • FIG. 3 is a diagram illustrating an example of transmission timing control between the radio base station and the mobile terminal.
  • the base station 211 detects a shift in transmission timing of the mobile terminal 221 based on the reception timing of the UL signal 301 (uplink signal) transmitted from the mobile terminal 221 at the base station 211. taking measurement.
  • Uplink signals include, for example, PUSCH (Physical Uplink Shared Channel: Physical Uplink Shared Channel), PUCCH (Physical Uplink Control: Physical Uplink Control Channel), SRS (Sounding Reference Signal), and the like.
  • PUSCH Physical Uplink Shared Channel: Physical Uplink Shared Channel
  • PUCCH Physical Uplink Control: Physical Uplink Control Channel
  • SRS Sounding Reference Signal
  • the base station 211 causes the mobile terminal 221 to adjust the transmission timing by transmitting the TA command 302 indicating the measured deviation to the mobile terminal 221 using the downlink radio resource.
  • the direction for adjusting the transmission timing includes a direction for advancing the transmission timing and a direction for delaying the transmission timing. Further, the base station 211 may notify the mobile terminal 221 that there is no transmission timing deviation by the TA command 302 when there is no transmission timing deviation of the mobile terminal 221.
  • FIG. 4A is a diagram of an example of a base station according to the second embodiment.
  • 4B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 4A.
  • the base station 211 is a base station that performs wireless communication using, for example, OFDMA (Orthogonal Frequency Division Multiplexing Access).
  • OFDMA Orthogonal Frequency Division Multiplexing Access
  • the base station 211 includes a transmission unit 410, a D / A conversion unit 421, a transmission RF unit 422, and an antenna 423. Further, the base station 211 includes a reception RF unit 424, an A / D conversion unit 425, a reception unit 430, a scheduling processing unit 440, and an S1 / X2 interface processing unit 450.
  • the transmission unit 410 performs modulation processing of a downlink signal transmitted from the base station 211.
  • the transmission unit 410 is a transmission unit corresponding to an OFDM (Orthogonal Frequency Division Multiplexing) transmission method.
  • the transmission unit 410 includes an error correction code unit 411, a data modulation unit 412, a data / pilot signal multiplexing unit 413, an IFFT unit 414, and a CP insertion unit 415.
  • error correction coding section 411, data modulation section 412, data / pilot signal multiplexing section 413, IFFT section 414, and CP insertion section 415 performs processing according to control information from scheduling processing section 440.
  • the error correction code unit 411 receives a downlink transmission data signal output from the S1 / X2 interface processing unit 450 and to be transmitted by the base station 211.
  • the error correction coding unit 411 performs error correction coding on the input transmission data signal.
  • error correction coding section 411 outputs the transmission data signal subjected to error correction coding to data modulation section 412.
  • the data modulation unit 412 performs modulation using the transmission data signal output from the error correction code unit 411.
  • QPSK Quadrature Phase Shift Keying
  • Data modulation section 412 outputs the transmission data signal obtained by the modulation to data / pilot signal multiplexing section 413.
  • the transmission data signal and pilot signal output from the data modulation unit 412 are input to the data / pilot signal multiplexing unit 413.
  • Data / pilot signal multiplexing section 413 multiplexes the input transmission data signal and pilot signal.
  • Data / pilot signal multiplexing section 413 then outputs the transmission signal obtained by multiplexing to IFFT section 414.
  • the IFFT unit 414 performs IFFT (Inverse Fast Fourier Transform) on the transmission signal output from the data / pilot signal multiplexing unit 413 in units of a certain number N. That is, IFFT section 414 regards N data samples as subcarrier signal components, performs IFFT processing on the subcarrier components, and converts them into discrete time signals. Then, IFFT section 414 outputs the transmission signal subjected to IFFT to CP insertion section 415.
  • IFFT Inverse Fast Fourier Transform
  • the CP insertion unit 415 inserts a CP (Cyclic Prefix: cyclic prefix) into the transmission signal output from the IFFT unit 414. Then, CP insertion section 415 outputs the transmission signal with the CP inserted to D / A conversion section 421.
  • CP insertion by the CP insertion unit 415 will be described later (see, for example, FIG. 5).
  • the D / A conversion unit 421 converts the transmission signal output from the transmission unit 410 into an analog signal. Then, the D / A conversion unit 421 outputs the transmission signal converted into the analog signal to the transmission RF unit 422.
  • the transmission RF unit 422 performs RF (Radio Frequency: high frequency) processing of the transmission signal output from the D / A conversion unit 421.
  • the RF processing by the transmission RF unit 422 includes, for example, conversion from a baseband frequency band to a radio frequency band. Then, the transmission RF unit 422 outputs the transmission signal subjected to the RF processing to the antenna 423.
  • the antenna 423 wirelessly transmits the transmission signal output from the transmission RF unit 422 to each mobile terminal including the mobile terminal 221. Further, the antenna 423 receives a signal wirelessly transmitted from each mobile terminal including the mobile terminal 221. Then, antenna 423 outputs the received signal (reception signal) to reception RF section 424.
  • the reception RF unit 424 performs RF processing on the reception signal output from the antenna 423.
  • the RF processing by the reception RF unit 424 includes, for example, conversion from a radio frequency band to a baseband frequency band. Then, the reception RF unit 424 outputs the reception signal subjected to the RF processing to the A / D conversion unit 425.
  • the A / D converter 425 converts the reception signal output from the reception RF unit 424 into a digital signal. Then, the A / D conversion unit 425 outputs the reception signal converted into the digital signal to the reception unit 430.
  • the receiving unit 430 performs demodulation processing on the received uplink signal.
  • the receiving unit 430 is a receiving unit corresponding to the SC-FDMA (Single Carrier-Frequency Division Multiplexing Access) transmission method adopted in LTE.
  • SC-FDMA Single Carrier-Frequency Division Multiplexing Access
  • PAPR Peak to Average Power Ratio
  • SC-FDMA Single Carrier-Frequency Division Multiplexing Access
  • the receiving unit 430 is required to collectively process the system bandwidth to be used due to the nature of the modulation / demodulation method. For this reason, timing adjustment is performed so that the time when the base station 211 receives the transmission data from each mobile terminal coincides. For example, in LTE, timing adjustment is performed using a TA command defined in TS36.213.
  • the reception unit 430 includes a CP removal unit 431, an FFT unit 432, a data / pilot signal separation unit 433, a data demodulation unit 434, an IDFT unit 435, an error correction decoding unit 436, and a pilot signal demodulation unit 437. And a timing detection unit 438.
  • Each of the CP removal unit 431, the FFT unit 432, and the data / pilot signal separation unit 433 performs processing according to the control information from the scheduling processing unit 440.
  • Each of data demodulating section 434, IDFT section 435, error correction decoding section 436, pilot signal demodulating section 437, and timing detecting section 438 performs processing in accordance with control information from scheduling processing section 440.
  • the CP removal unit 431 removes the CP inserted in the reception signal output from the A / D conversion unit 425. Then, CP removing section 431 outputs the reception signal from which CP is removed to FFT section 432.
  • the FFT unit 432 performs FFT (Fast Fourier Transform) on the received signal output from the CP removal unit 431. Then, FFT section 432 outputs the received signal subjected to the FFT to data / pilot signal separation section 433.
  • FFT Fast Fourier Transform
  • the data / pilot signal demultiplexing unit 433 demultiplexes the received signal output from the FFT unit 432.
  • Data / pilot signal demultiplexing section 433 outputs the received data signal of each physical channel obtained by demultiplexing to data demodulation section 434.
  • Each physical channel includes, for example, RACH (Random Access Channel), PUSCH, PUCCH, and the like.
  • the data / pilot signal demultiplexing unit 433 outputs the pilot signal obtained by demultiplexing to the pilot signal demodulation unit 437. Further, the data / pilot signal demultiplexing unit 433 outputs the received data obtained by the demultiplexing to the timing detection unit 438.
  • the reception data output from the data / pilot signal separation unit 433 to the timing detection unit 438 is, for example, a pilot signal. In the case of LTE, for example, this pilot signal is DRS (Demodulation Reference Signals) or SRS defined in TS 36.211.
  • the data demodulating unit 434 demodulates the received data signal output from the data / pilot signal separating unit 433 based on the demodulation result of the pilot signal output from the pilot signal demodulating unit 437. Data demodulation section 434 then outputs the received data signal obtained by demodulation to IDFT section 435.
  • the IDFT unit 435 performs IDFT (Inverse Discrete Fourier Transform) on the received data signal output from the data demodulation unit 434. IDFT section 435 then outputs the received data signal subjected to IDFT to error correction decoding section 436.
  • IDFT Inverse Discrete Fourier Transform
  • the error correction decoding unit 436 performs error correction decoding on the received data signal output from the IDFT unit 435. Then, error correction decoding section 436 outputs the received data signal obtained by error correction decoding to S1 / X2 interface processing section 450. Further, error correction decoding section 436 outputs the reception processing result by error correction decoding to scheduling processing section 440.
  • the reception processing results include, for example, error detection results (ACK (ACKnowledgement) / NACK (Negative ACKnowledgement)), CQI (Channel Quality Indicator), and the like.
  • pilot signal demodulator 437 demodulates the pilot signal output from the data / pilot signal separator 433. Pilot signal demodulation section 437 then outputs the demodulation result of the pilot signal to data demodulation section 434.
  • the timing detection unit 438 detects the timing of each mobile terminal based on the received data (for example, pilot signal) output from the data / pilot signal separation unit 433. Then, the timing detection unit 438 outputs a TA command based on the timing detection to the scheduling processing unit 440. Timing detection by the timing detection unit 438 will be described later (see, for example, FIGS. 6A and 6B).
  • the scheduling processing unit 440 performs scheduling for selecting a mobile terminal (for example, the mobile terminal 221) that performs wireless communication with the base station 211 based on the reception processing result output from the error correction decoding unit 436. That is, in a system such as a mobile phone, one base station 211 handles a plurality of mobile terminals. Therefore, the scheduling processing unit 440 installed in the base station 211 selects a mobile terminal that actually performs data communication from among a plurality of mobile terminals for each of the uplink and the downlink.
  • the scheduling processing unit 440 determines a transmission target mobile terminal based on an index value calculated based on channel quality and a transmission data rate, and determines a transmission speed, a modulation scheme, and the like and allocates radio resources. be able to. And the scheduling process part 440 controls the transmission part 410 and the receiving part 430 by outputting the control information according to the result of scheduling.
  • the Maximum CIR (Carrier-to-Interference power Ratio) method or the PF (Proportional Fairness) method can be used for the scheduling by the scheduling processing unit 440.
  • the scheduling processing unit 440 causes the mobile terminal 221 to control transmission timing by storing a TA command in, for example, a RACH response (message 2) that is transmitted from the transmission unit 410 for a random access signal.
  • the RACH response (message 2) is defined in, for example, TS36.321 (6.1.5 MAC PDU (Random Access Response)).
  • the scheduling processing unit 440 stores, for example, a TA command that stores a MAC Control Element (Medium Control Control Element) defined in TS36.321 (6.1.3.5 Timing Advance Command MAC Control Element) by a TA command.
  • the mobile terminal 221 may be controlled to control transmission timing.
  • the transmission timing control procedure (Timing Advance procedure) of the mobile terminal 221 has two stages of “Initial Timing Advance” and “Timing Advance Updates”.
  • a TA command (11 [bit]) is transmitted from the base station 211 to the mobile terminal 221 by “RACH response”.
  • a TA command (6 [bit]) is transmitted from the base station 211 to the mobile terminal 221 by MAC Control Element.
  • the scheduling processing unit 440 transmits the TA command to each mobile terminal by outputting the TA command for each mobile terminal output from the timing detection unit 438 to the transmission unit 410.
  • the transmission unit 410, the reception unit 430, and the scheduling processing unit 440 can be realized by the digital circuit 401, for example.
  • the digital circuit 401 for example, an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor) can be used.
  • the S1 / X2 interface processing unit 450 is a transmission / reception data interface including an S1 interface 231 for communicating with the core network 240, an X2 interface 250 for communicating with the base station 212, and the like.
  • the S1 / X2 interface processing unit 450 outputs the downlink transmission data signal received from the core network 240 by the S1 interface 231 to the transmission unit 410.
  • the S1 / X2 interface processing unit 450 transmits the reception data signal output from the reception unit 430 to the core network 240 through the S1 interface 231.
  • FIG. 5 is a diagram illustrating an example of CP insertion processing.
  • a signal 510 illustrated in FIG. 5 is an N-sample signal (a signal after IFFT) output from the IFFT unit 414.
  • Signal 520 is a signal obtained by inserting CP into signal 510 by CP insertion section 415 (signal after CP insertion).
  • the CP insertion unit 415 inserts the CP 521, which is a copy of the tail portion 511 (N> M), which is the tail M sample of the N-sample signal 510, at the head of the signal 510, so that the signal 520 of (M + N) samples. (M + N sample OFDM symbol) is generated. Since CP 521 is copied cyclically, the signal continues in the section of (M + N) samples of signal 520. As a result, the CP can remove interference caused by delay symbols from adjacent paths.
  • FIG. 6A is a diagram illustrating an example of a timing detection unit.
  • FIG. 6B is a diagram illustrating an example of a signal flow in the timing detection unit illustrated in FIG. 6A.
  • the timing detection unit 438 includes a correlation detection code generation unit 601, a correlation detection unit 602, a power conversion unit 603, and a TA command generation unit 604, for example, as shown in FIGS. 6A and 6B.
  • the correlation detection code generation unit 601 generates a correlation detection code and outputs it to the correlation detection unit 602.
  • the code for correlation detection is, for example, the same signal as a pilot signal from a mobile terminal.
  • Correlation detection section 602 obtains the correlation value between the uplink reception data (pilot signal) output from data / pilot signal separation section 433 and the correlation detection code output from correlation detection code generation section 601. To detect. Then, correlation detection section 602 outputs the detected correlation value to power conversion section 603.
  • a correlation detector such as a matched filter (MF) can be used.
  • the power conversion unit 603 performs power conversion by squaring the correlation value output from the correlation detection unit 602. Then, the power conversion unit 603 outputs the signal obtained by the power conversion to the TA command generation unit 604 as a delay profile.
  • the TA command generation unit 604 generates a TA command based on the delay profile output from the power conversion unit 603. Then, the TA command generation unit 604 outputs the generated TA command to the scheduling processing unit 440.
  • FIG. 7 is a diagram illustrating an example of a delay profile.
  • the vertical axis indicates the reception level, and the horizontal axis indicates time.
  • the delay profile 701 is a delay profile output from the power conversion unit 603 of the timing detection unit 438 illustrated in FIGS. 6A and 6B to the TA command generation unit 604.
  • the TA command generation unit 604 can determine that uplink data transmission has occurred when the peak reception level in the delay profile 701 exceeds a predetermined detection threshold 702.
  • the TA command generation unit 604 can calculate, for example, the propagation delay time for the mobile terminal 221 from the difference between the predetermined processing reference timing 703 in the base station 211 and the uplink signal.
  • the difference between the processing reference timing 703 and the uplink signal can be measured, for example, by calculating a timing difference 705 between the timing 704 having the largest reception level in the delay profile 701 and the processing reference timing 703. .
  • the TA command generation unit 604 generates a TA command including information indicating the calculated timing difference 705.
  • the TA command generated by the TA command generation unit 604 is transmitted to the mobile terminal 221. Thereby, the transmission timing of the radio signal in the mobile terminal 221 is adjusted.
  • FIG. 8A is a diagram illustrating an example of a mobile terminal according to the second embodiment.
  • FIG. 8B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 8A.
  • the mobile terminal 221 includes a control unit 810, a transmission unit 821, a D / A conversion unit 822, a transmission RF unit 823, an antenna 830, and a reception RF unit 841. , An A / D converter 842, and a receiver 843.
  • the mobile terminal 221 includes a timer 844, a TA command accumulation unit 845, an autonomous adjustment control determination processing unit 846, and a parameter calculation unit 847.
  • the control unit 810 performs data transmission control of the transmission unit 821 for the uplink based on the radio resource allocation information output from the reception unit 843. Also, the control unit 810 performs data reception control of the receiving unit 843 for the downlink based on the radio resource allocation information output from the receiving unit 843.
  • control unit 810 performs transmission timing control of the transmission unit 821 for the uplink based on the TA command output from the reception unit 843. In addition, the control unit 810 performs transmission timing control based on the parameters for autonomous adjustment output from the parameter calculation unit 847. In addition, when the timing which performs autonomous adjustment and the timing which performs control by TA command overlap, for example, control by TA command is performed preferentially.
  • the transmission unit 821 performs modulation processing on the uplink signal to be transmitted. Then, the transmission unit 821 outputs the transmission signal obtained by the modulation process to the D / A conversion unit 822.
  • the D / A conversion unit 822 converts the transmission signal output from the transmission unit 821 into an analog signal. Then, the D / A conversion unit 822 outputs the transmission signal converted into the analog signal to the transmission RF unit 823.
  • the transmission RF unit 823 performs RF processing on the transmission signal output from the D / A conversion unit 822.
  • the RF processing by the transmission RF unit 823 includes, for example, conversion from a baseband frequency band to a radio frequency band. Then, transmission RF section 823 outputs the transmission signal subjected to the RF processing to antenna 830.
  • the antenna 830 wirelessly transmits the transmission signal output from the transmission RF unit 823 to the base station 211.
  • the antenna 830 receives a signal wirelessly transmitted from the base station 211.
  • Antenna 830 then outputs the received signal (reception signal) to reception RF section 841.
  • the reception RF unit 841 performs RF processing on the reception signal output from the antenna 830.
  • the RF processing by the reception RF unit 841 includes, for example, conversion from a radio frequency band to a baseband frequency band. Then, the reception RF unit 841 outputs the reception signal subjected to the RF processing to the A / D conversion unit 842.
  • the A / D conversion unit 842 converts the reception signal output from the reception RF unit 841 into a digital signal. Then, the A / D conversion unit 842 outputs the reception signal converted into the digital signal to the reception unit 843.
  • the reception unit 843 performs detection demodulation processing on the reception signal output from the A / D conversion unit 842. In addition, receiving section 843 outputs radio resource allocation information and TA command obtained by the detection demodulation process to control section 810. In addition, the reception unit 843 outputs the TA command to the TA command accumulation unit 845.
  • the timer 844 is a timer that measures a predetermined time interval and outputs a timer value indicating the time measurement result to the TA command accumulation unit 845 and the autonomous adjustment control determination processing unit 846. For example, the timer 844 outputs a timer value for performing TA command accumulation processing to the TA command accumulation unit 845.
  • the timer 844 includes a start determination timer for determining whether or not to start autonomous adjustment, and a stop determination timer for determining whether or not to stop autonomous adjustment, and these timers The value is output to the autonomous adjustment control determination processing unit 846.
  • the TA command accumulating unit 845 performs accumulative calculation processing for a certain period of time of the TA command output from the receiving unit 843 based on the timer value output from the timer 844.
  • the TA command accumulating process in the TA command accumulating unit 845 can be a process in which the accumulated value is reset once when a certain time elapses and the calculation is performed again.
  • the TA command accumulation unit 845 outputs the TA command accumulation calculation processing result to the autonomous adjustment control determination processing unit 846.
  • the autonomous adjustment control determination processing unit 846 compares the cumulative calculation processing result output from the TA command accumulation unit 845 with the threshold value based on the timer value output from the timer 844, thereby determining whether the autonomous adjustment control is necessary. Determine. Then, the autonomous adjustment control determination processing unit 846 outputs the determination result to the parameter calculation unit 847.
  • the parameter calculation unit 847 calculates a parameter for autonomous adjustment when it is determined to perform autonomous adjustment based on the determination result output from the autonomous adjustment control determination processing unit 846.
  • the parameters for autonomous adjustment include, for example, a transmission timing control amount and a correction interval.
  • the parameter calculation unit 847 includes an instruction to start or stop autonomous adjustment (autonomous adjustment start / stop instruction) according to the determination result output from the autonomous adjustment control determination processing unit 846, the calculated parameter for autonomous adjustment, Is output to the control unit 810.
  • the parameter calculation unit 847 performs autonomous adjustment with respect to the control unit 810 when the autonomous adjustment control determination processing unit 846 determines that autonomous adjustment is not performed when the control unit 810 performs autonomous adjustment. To stop.
  • Control unit 810, transmission unit 821, reception unit 843, timer 844, TA command accumulation unit 845, autonomous adjustment control determination processing unit 846, and parameter calculation unit 847 can be realized by a digital circuit 801, for example.
  • a digital circuit 801 for example, an FPGA or a DSP can be used.
  • the 1A and 1B can be realized by, for example, the transmission unit 821, the D / A conversion unit 822, the transmission RF unit 823, and the antenna 830.
  • the receiving unit 112 illustrated in FIGS. 1A and 1B can be realized by the antenna 830, the receiving RF unit 841, the A / D conversion unit 842, and the receiving unit 843, for example.
  • the storage unit 113 shown in FIGS. 1A and 1B can be realized by a memory provided in the digital circuit 801, for example.
  • the adjustment unit 114 illustrated in FIGS. 1A and 1B can be realized by the control unit 810, the timer 844, the TA command accumulation unit 845, the autonomous adjustment control determination processing unit 846, and the parameter calculation unit 847, for example.
  • FIGS. 9A and 9B are flowcharts illustrating an example of processing performed by the mobile terminal according to the second embodiment.
  • the mobile terminal 221 communicates with the base station 211, the mobile terminal 221 executes, for example, each step shown in FIGS. 9A and 9B. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the mobile terminal 221 determines whether a TA command has been received from the base station 211 (step S901). If the TA command has not been received (step S901: No), the mobile terminal 221 moves to step S908. When the TA command is received (step S901: Yes), the mobile terminal 221 adjusts the transmission timing of its own station using the received TA command value (step S902).
  • the mobile terminal 221 determines whether or not the own station is undergoing autonomous adjustment (step S903).
  • the mobile terminal 221 performs a received TA command accumulation process for stop determination (step S904), and proceeds to step S908.
  • the mobile terminal 221 adds the value of the TA command received in step S901 to the received TA command accumulated value for stop determination.
  • step S903 when the autonomous adjustment is not being performed (step S903: No), the mobile terminal 221 determines whether or not the autonomous adjustment start processing determination has been started in step S906 described later (step S905). When the start process determination has been started (step S905: Yes), the mobile terminal 221 moves to step S907.
  • step S905 when the start process determination has not been started (step S905: No), the mobile terminal 221 activates an autonomous adjustment start determination timer (step S906). Thereby, the start process determination of autonomous adjustment is started.
  • the start determination timer is a timer that measures the start determination timing of a predetermined cycle, for example.
  • step S907 the mobile terminal 221 adds the value of the TA command received in step S901 to the received TA command accumulated value for start determination.
  • step S908 determines whether or not the own station is undergoing autonomous adjustment.
  • step S909 determines whether or not the current time is the start timing of autonomous adjustment.
  • the determination in step S909 can be performed based on, for example, the start determination timer activated in step S906.
  • step S909 when it is not the start timing of autonomous adjustment (step S909: No), the mobile terminal 221 proceeds to step S916.
  • step S916 When it is the start determination timing of the autonomous adjustment (step S909: Yes), the mobile terminal 221 compares the received TA command accumulated value for start determination with the threshold Th_TA1 (step S910).
  • the mobile terminal 221 determines whether or not autonomous adjustment is required based on the comparison result in step S910 (step S911). For example, if the absolute value (cumulative value) of the received TA command cumulative value is greater than the threshold value Th_TA1, the mobile terminal 221 determines that autonomous adjustment is required, and the received TA command cumulative value (cumulative value) is equal to or less than the threshold value Th_TA1. If it is, it is determined that autonomous adjustment is not required.
  • step S911 determines whether autonomous adjustment is not required (step S911: No). If it is determined in step S911 that autonomous adjustment is not required (step S911: No), the mobile terminal 221 proceeds to step S915. If it is determined that autonomous adjustment is required (step S911: Yes), the mobile terminal 221 calculates parameters for autonomous adjustment (step S912). Calculation of parameters for autonomous adjustment includes calculation of TA command change speed, determination of correction interval, and the like. Calculation of the TA command change rate and determination of the correction interval will be described later.
  • the mobile terminal 221 starts autonomous adjustment based on the parameters for autonomous adjustment calculated in step S912 (step S913). That is, the mobile terminal 221 shifts to a state during autonomous adjustment. Thereby, the mobile terminal 221 starts an autonomous adjustment process for adjusting the transmission timing at a predetermined correction interval in parallel with the processes shown in FIGS. 9A and 9B.
  • the mobile terminal 221 activates the autonomous adjustment start timer and the autonomous adjustment stop determination timer, and stops the autonomous adjustment start determination timer activated in step S906 (step S914).
  • the autonomous adjustment start timer is, for example, a timer that times the timing (correction interval) for executing autonomous adjustment.
  • the stop determination timer is, for example, a timer that measures stop determination timing of a predetermined cycle.
  • the predetermined period (Y [sec]) can be set to a sufficiently long period (for example, several times or more) with respect to a periodic TA command transmission interval or each measurement period, for example. This is because if the predetermined period is short, it is likely to be affected by momentary irregular TA command transmission fluctuations and variations (deviation). Further, when the predetermined period is shorter than each measurement period, it is determined that the autonomous adjustment is stopped without obtaining the measurement result.
  • This predetermined cycle may be changed flexibly by changing the software according to the field environment, for example.
  • the mobile terminal 221 initializes the received TA command cumulative value for start determination (step S915).
  • the mobile terminal 221 determines whether or not communication with the base station 211 is being continued (step S916). When communication is continuing (step S916: Yes), the mobile terminal 221 returns to step S901.
  • step S916 when the communication is not continued (step S916: No), the mobile terminal 221 stops the autonomous adjustment, resets the autonomous adjustment process (step S917), and ends the series of processes.
  • step S917 the mobile terminal 221 may not perform the process of stopping the autonomous adjustment when the autonomous adjustment is not being performed.
  • step S908 when the own station is performing autonomous adjustment (step S908: Yes), the mobile terminal 221 determines whether or not the current time is an autonomous adjustment stop determination timing (step S918).
  • the determination in step S918 can be made based on, for example, the stop determination timer started in step S914.
  • step S918 when it is not the autonomous adjustment stop determination timing (step S918: No), the mobile terminal 221 proceeds to step S922.
  • step S918: Yes the mobile terminal 221 compares the received TA command accumulated value with the threshold Th_TA2 (step S919).
  • the threshold Th_TA2 is a threshold set separately from the threshold Th_TA1, for example, and may be the same as or different from the threshold Th_TA1.
  • the threshold Th_TA2 can be a value equal to or greater than the threshold Th_TA1.
  • the mobile terminal 221 determines whether or not to continue the autonomous adjustment based on the comparison result in step S919 (step S920). For example, when the absolute value (cumulative value) of the received TA command cumulative value is smaller than the threshold value Th_TA2, the mobile terminal 221 determines that the autonomous adjustment is continued, and the absolute value (cumulative value) of the received TA command cumulative value is equal to or greater than the threshold value Th_TA2. If it is, it is determined that the autonomous adjustment is not continued.
  • step S920 when it is determined that the autonomous adjustment is continued (step S920: Yes), the mobile terminal 221 initializes the received TA command cumulative value for stop determination (step S921). And the mobile terminal 221 continues an autonomous adjustment (step S922), and transfers to step S916. In addition, when the process for continuing an autonomous adjustment is unnecessary, step S922 may be omitted.
  • step S920 If it is determined in step S920 that the autonomous adjustment is not continued (step S920: No), the mobile terminal 221 stops the autonomous adjustment, resets the autonomous adjustment process (step S923), and proceeds to step S916.
  • the mobile terminal 221 starts autonomous adjustment when the absolute value of the cumulative value of the TA command within a certain time exceeds the threshold Th_TA1. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large. Further, the mobile terminal 221 can continue the autonomous adjustment while the absolute value of the cumulative value of the TA command value within a certain time is below the threshold value Th_TA2. Thereby, when the fluctuation
  • the mobile terminal 221 may use the number of times of reception of the TA command value within a certain time instead of the absolute value of the cumulative value of the TA command within a certain time. Since the TA command is transmitted more frequently as the variation in the transmission timing deviation is larger, the autonomous adjustment can be started when the variation in the transmission timing deviation is larger. In addition, the autonomous adjustment can be continued when the variation in the transmission timing deviation is suppressed by the autonomous adjustment.
  • FIG. 10 is a flowchart of a modification of the process performed by the mobile terminal according to the second embodiment.
  • the mobile terminal 221 may execute the steps shown in FIG. 10 when communicating with the base station 211. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the mobile terminal 221 determines whether a TA command has been received from the base station 211 (step S1001). If the TA command has not been received (step S1001: No), the mobile terminal 221 moves to step S1016. When the TA command is received (step S1001: Yes), the mobile terminal 221 adjusts the transmission timing of its own station using the received TA command value (step S1002).
  • the mobile terminal 221 stores the value of the TA command received in step S1001 and the reception time of the TA command in step S1001 in the memory (step S1003).
  • step S1004 determines whether or not the local station is undergoing autonomous adjustment.
  • step S1004 No
  • step S1005 When autonomous adjustment is not being performed (step S1004: No), past TA commands are accumulated starting from the TA command received in step S1001, and the time until the accumulated value reaches the threshold Th_TA1 is calculated (step S1005).
  • step S1005 the mobile terminal 221 calculates the length of the latest past period and the period during which the TA command whose accumulated value corresponds to the threshold value Th_TA1 is received. For example, when the accumulated TA command accumulated value is small and the accumulated value does not reach the threshold Th_TA1, the calculation result in step S1005 can be set to ⁇ (infinity).
  • the mobile terminal 221 compares the time until the accumulated value calculated in step S1005 reaches the threshold Th_TA1 with the threshold Th_time1 (step S1006).
  • the mobile terminal 221 determines whether or not autonomous adjustment is required based on the comparison result in step S1006 (step S1007). For example, the mobile terminal 221 determines that autonomous adjustment is required when the time calculated at step S1005 is smaller than the threshold Th_time1, and determines that autonomous adjustment is not required when the time calculated at step S1005 is equal to or greater than the threshold Th_time1. .
  • step S1007 If it is determined in step S1007 that autonomous adjustment is not required (step S1007: No), the mobile terminal 221 moves to step S1011. If it is determined that autonomous adjustment is required (step S1007: Yes), the mobile terminal 221 proceeds to step S1008. Steps S1008 and S1009 are the same as steps S912 and S913 shown in FIG. 9B.
  • step S1010 the mobile terminal 221 starts an autonomous adjustment start timer.
  • the autonomous adjustment start timer is, for example, a timer that times the timing (correction interval) for executing autonomous adjustment.
  • step S1011 and S1012 are the same as steps S916 and S917 shown in FIG. 9B.
  • step S1004 when autonomous adjustment is being performed (step S1004: Yes), the mobile terminal 221 proceeds to step S1013. That is, the mobile terminal 221 accumulates past TA commands starting from the TA command received in step S1001, and calculates the time until the accumulated value reaches the threshold Th_TA2 (step S1013).
  • step S1013 the mobile terminal 221 calculates the length of the latest past period and the period in which the TA command whose accumulated value corresponds to the threshold value Th_TA2 is received. For example, if the accumulated TA command accumulated value is small and the accumulated value does not reach the threshold Th_TA2, the calculation result in step S1013 can be set to ⁇ (infinity).
  • the mobile terminal 221 compares the time until the cumulative value calculated in step S1013 reaches the threshold Th_TA2 with the threshold Th_time2 (step S1014).
  • the mobile terminal 221 determines whether or not to continue the autonomous adjustment based on the comparison result in step S1014 (step S1015). For example, the mobile terminal 221 determines that the autonomous adjustment is continued if the time calculated in step S1013 is larger than the threshold Th_time2, and determines that the autonomous adjustment is not continued if the time calculated in step S1013 is equal to or less than the threshold Th_time2. .
  • Step S1015 when it is determined that the autonomous adjustment is continued (Step S1015: Yes), the mobile terminal 221 continues the autonomous adjustment (Step S1016), and proceeds to Step S1011. Note that step S1016 may be omitted when the process for continuing the autonomous adjustment is unnecessary.
  • step S1015 If it is determined in step S1015 that the autonomous adjustment is not continued (step S1015: No), the mobile terminal 221 stops the autonomous adjustment and resets the autonomous adjustment process (step S1017), and proceeds to step S1011.
  • the mobile terminal 221 starts autonomous adjustment when the time until the absolute value of the cumulative value of the TA command value reaches the threshold Th_TA1 falls below the threshold Th_time1. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the mobile terminal 221 can continue the autonomous adjustment while the time until the absolute value of the cumulative value of the TA command value reaches the threshold Th_TA2 exceeds the threshold Th_time2. Thereby, when the fluctuation
  • the mobile terminal 221 may use the time until the TA command reception count reaches the threshold, instead of the time until the cumulative value of the TA command reaches the threshold. Since the TA command is transmitted more frequently as the variation in the transmission timing deviation is larger, the autonomous adjustment can be started when the variation in the transmission timing deviation is larger. In addition, the autonomous adjustment can be continued when the variation in the transmission timing deviation is suppressed by the autonomous adjustment.
  • the mobile terminal 221 calculates the TA command change speed by the following equation (1), for example.
  • TA command change rate cumulative value of received TA command / cumulative time ... (1)
  • the TA command change speed can also take positive and negative values according to the above equation (1).
  • a 6-bit TA command value is used to indicate a positive or negative integer value.
  • the TA command value is a value in the range of 0 to 63 when expressed in decimal.
  • the mobile terminal 221 can obtain a positive or negative value by subtracting 31 from the 6-bit value of the received TA command.
  • the command value can be acquired. That is, the “accumulated value of received TA command” in the above equation (1) is converted to a positive or negative value by subtracting a predetermined value (eg, 31) from the 6-bit value of the received TA command.
  • the accumulated value can be a cumulative value.
  • the base station 211 stores a 6-bit TA command in the MAC Control Element.
  • the mobile terminal 221 stores the TA value of the received TA command.
  • the mobile terminal 221 uses the stored TA values to recursively express the following formula (2) defined in, for example, TS36.213 (4.2.3 Transmission timing adjustments).
  • the calculated value (N TA, new ) is used as the “cumulative value of received TA command” in the above equation (1).
  • N TA, new N TA, old + (T A -31) ⁇ 16 ... (2)
  • N TA old is N TA, new obtained in the previous calculation in the recursive calculation of the equation (2).
  • T A is the TA value the mobile terminal 221 is stored.
  • “Accumulated time” in the above equation (1) is a period of X times of the immediately preceding TA command. This “cumulative time” (or X) may be flexibly changeable by software change or the like according to the field environment.
  • the mobile terminal 221 calculates the transmission timing control amount [sec] based on the TA command change rate calculated by the above equation (1) and the following equation (3).
  • the mobile terminal 221 adjusts the transmission timing by the calculated transmission timing control amount [sec] for each correction interval.
  • the correction interval can be set to a preset fixed value, for example. This correction interval may be changed flexibly by changing the software according to the field environment, for example.
  • the mobile terminal 221 holds a plurality of TA commands received from the base station 211, and based on the held plurality of TA commands, the shift of the radio signal transmission timing by the mobile terminal 221 is suppressed. Estimate changes. Then, the mobile terminal 221 performs autonomous adjustment of the transmission timing based on the estimation result of the change in the radio signal transmission timing shift by the mobile terminal 221. Thereby, the transmission timing can be accurately adjusted even when the instruction signal is not transmitted from the base station apparatus 120.
  • the mobile terminal 221 may adjust the correction interval for autonomous adjustment based on the moving speed of its own station.
  • FIG. 11A and FIG. 11B are diagrams showing an example of the moving speed and the correction interval of the mobile terminal.
  • the horizontal axis indicates the moving speed [km / h] of the mobile terminal 221
  • the vertical axis indicates the transmission timing correction interval [sec] of the mobile terminal 221.
  • the relationship 1110 indicates the relationship between the moving speed of the mobile terminal 221 and the transmission timing correction interval of the mobile terminal 221. As in the relationship 1110, the transmission interval can be adjusted more frequently as the transmission timing tends to shift by decreasing the correction interval as the moving speed is higher.
  • the transmission timing adjustment frequency is reduced to reduce the amount of processing, and when the transmission timing deviation variation is large, the transmission timing adjustment frequency is increased to increase the transmission timing. Deviation can be suppressed. For this reason, the transmission timing can be adjusted efficiently.
  • the table 1120 shown in FIG. 11B is correspondence information indicating correction intervals for each moving speed based on the relationship 1110.
  • a table 1120 is stored in the memory of the mobile terminal 221.
  • the mobile terminal 221 acquires a correction interval corresponding to the current moving speed of the local station in the table 1120, and adjusts transmission timing according to the acquired correction interval.
  • the moving speed of the mobile terminal 221 can be determined based on, for example, a GPS (Global Positioning System) unit provided in the mobile terminal 221 or an acceleration sensor.
  • a GPS Global Positioning System
  • the table 1120 may be flexibly changeable by software change in accordance with the field environment, for example.
  • the mobile terminal 221 may adjust the correction interval for autonomous adjustment based on the accumulated value of the received TA command.
  • FIG. 12A and 12B are diagrams showing examples of TA command accumulated values and correction intervals.
  • the horizontal axis indicates the cumulative value (absolute value) of TA commands received by the mobile terminal 221
  • the vertical axis indicates the transmission timing correction interval [sec] of the mobile terminal 221.
  • a relationship 1210 indicates a relationship between the cumulative value of TA commands received by the mobile terminal 221 and the transmission timing correction interval of the mobile terminal 221. As in the relation 1210, the correction interval is decreased as the absolute value of the accumulated value of the TA command is increased, so that the transmission timing can be adjusted more frequently as the transmission timing is easily shifted.
  • the transmission timing adjustment frequency is reduced to reduce the amount of processing, and when the transmission timing deviation variation is large, the transmission timing adjustment frequency is increased to increase the transmission timing. Deviation can be suppressed. For this reason, the transmission timing can be adjusted efficiently.
  • the table 1220 shown in FIG. 12B is correspondence information indicating correction intervals for each cumulative value of TA commands based on the relationship 1210.
  • a table 1220 is stored in the memory of the mobile terminal 221.
  • the mobile terminal 221 acquires a correction interval corresponding to the accumulated value of the TA command for the most recent predetermined period, and adjusts the transmission timing according to the acquired correction interval.
  • the mobile terminal 221 may determine the correction interval for autonomous adjustment based on the combination of the moving speed of the local station and the cumulative value of the TA command.
  • the mobile terminal 221 determines the autonomous transmission timing using the TA command received in the past separately from the adjustment of the transmission timing according to the TA command from the base station 211. Adjustments can be made. As a result, the number of TA command transmissions from the base station 211 can be reduced.
  • the mobile terminal 221 determines whether or not to perform autonomous transmission timing adjustment based on the cumulative value of the TA command value or the number of receptions. Thereby, when the transmission timing deviation is large, autonomous adjustment can be performed, and fluctuations in the transmission timing deviation can be suppressed.
  • the mobile terminal 221 determines whether to continue the adjustment of the autonomous transmission timing based on the cumulative value of the TA command value or the number of receptions. To do. Autonomous adjustment can be continued when fluctuations in transmission timing deviation are suppressed by autonomous adjustment.
  • FIG. 13A is a diagram illustrating an example of a mobile terminal according to the third embodiment.
  • FIG. 13B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 13A. 13A and 13B, the same parts as those shown in FIGS. 8A and 8B are denoted by the same reference numerals, and description thereof is omitted.
  • the mobile terminal 221 according to the third embodiment includes a moving speed measuring unit 1301 instead of the TA command accumulating unit 845 shown in FIGS. 8A and 8B.
  • the reception unit 843 outputs the reception result of the pilot signal from the base station 211 to the moving speed measurement unit 1301.
  • the moving speed measuring unit 1301 measures the moving speed of the own station. Then, the movement speed measurement unit 1301 outputs the measurement result of the movement speed to the autonomous adjustment control determination processing unit 846.
  • the moving speed measurement unit 1301 estimates the fading frequency between the base station 211 and the base station 211 based on the reception result of the pilot signal output from the reception unit 843, and based on the estimation result of the fading frequency. Measure the moving speed of the station.
  • the moving speed of the mobile terminal 221 can be calculated by, for example, the fading frequency between the mobile terminal 221 and the base station 211 and the following equation (4).
  • Movement speed of mobile terminal [m / s] Wavelength of carrier used for radio [m] ⁇ fading frequency [Hz] (4)
  • the fading frequency estimation between the mobile terminal 221 and the base station 211 is not limited to the method using the reception result of the pilot signal, and various methods can be used.
  • the measurement of the moving speed of the base station 211 is not limited to the method using the estimation result of the fading frequency, and various methods such as a method using a GPS unit or an acceleration sensor can be used.
  • the autonomous adjustment control determination processing unit 846 Based on the timer value output from the timer 844, the autonomous adjustment control determination processing unit 846 compares the measurement result of the movement speed output from the movement speed measurement unit 1301 with a threshold value to determine whether or not the autonomous adjustment is necessary. Determine.
  • FIG. 14 is a flowchart of an example of processing performed by the mobile terminal according to the third embodiment.
  • the mobile terminal 221 communicates with the base station 211, the mobile terminal 221 executes, for example, each step shown in FIG. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the mobile terminal 221 determines whether a TA command has been received from the base station 211 (step S1401). If the TA command has not been received (step S1401: No), the mobile terminal 221 moves to step S1403. When the TA command is received (step S1401: Yes), the mobile terminal 221 adjusts the transmission timing of its own station using the received TA command value (step S1402).
  • the mobile terminal 221 calculates the moving speed of its own station (step S1403).
  • the mobile terminal 221 determines whether or not the own station is undergoing autonomous adjustment (step S1404).
  • the mobile terminal 221 determines whether or not the autonomous adjustment start process determination has been started in step S1406 (step S1405).
  • the start process determination has been started (step S1405: Yes)
  • the mobile terminal 221 moves to step S1407.
  • step S1405 if the start process determination has not been started (step S1405: No), the mobile terminal 221 activates a start timer for determination of autonomous adjustment (step S1406). Thereby, the start process determination of autonomous adjustment is started.
  • the start determination timer is a timer that measures the start determination timing of a predetermined cycle, for example.
  • step S1407 the mobile terminal 221 determines whether or not the current time is an autonomous adjustment start determination timing.
  • the determination in step S1407 can be made based on the start determination timer activated in step S1406, for example.
  • step S1407 when it is not the start timing of autonomous adjustment (step S1407: No), the mobile terminal 221 moves to step S1413.
  • step S1407: Yes the mobile terminal 221 compares the moving speed calculated in step S1403 with the threshold Th_v1 (step S1408).
  • the mobile terminal 221 determines whether or not autonomous adjustment is required based on the comparison result in step S1408 (step S1409). For example, the mobile terminal 221 determines that autonomous adjustment is required when the moving speed is greater than the threshold Th_v1, and determines that autonomous adjustment is not required when the moving speed is equal to or less than the threshold Th_v1.
  • step S1409 If it is determined in step S1409 that autonomous adjustment is not required (step S1409: No), the mobile terminal 221 proceeds to step S1413. If it is determined that autonomous adjustment is required (step S1409: Yes), the mobile terminal 221 proceeds to step S1410. Steps S1410 to S1412 are the same as steps S912 to S914 shown in FIG. 9B. After step S1412, the mobile terminal 221 moves to step S1413. Steps S1413 and S1414 are the same as steps S916 and S917 shown in FIG. 9B.
  • step S1404 when the own station is performing autonomous adjustment (step S1404: Yes), the mobile terminal 221 determines whether or not the current time is an autonomous adjustment stop determination timing (step S1415). The determination in step S1415 can be made based on the stop determination timer activated in step S1412, for example.
  • step S1415 when it is not the autonomous adjustment stop determination timing (step S1415: No), the mobile terminal 221 continues the autonomous adjustment (step S1416), and proceeds to step S1413. Note that step S1416 may be omitted when the process for continuing the autonomous adjustment is unnecessary.
  • step S1415 when it is the autonomous adjustment stop determination timing (step S1415: Yes), the mobile terminal 221 compares the movement speed calculated in step S1403 with the threshold Th_v2 (step S1417).
  • the threshold value Th_v2 is a threshold value set separately from the threshold value Th_v1, for example, and may be the same as or different from the threshold value Th_v1.
  • the mobile terminal 221 determines whether or not to continue the autonomous adjustment based on the comparison result in step S1417 (step S1418). For example, the mobile terminal 221 determines that the autonomous adjustment is continued when the moving speed is greater than the threshold Th_v2, and determines that the autonomous adjustment is not continued when the moving speed is equal to or less than the threshold Th_v2.
  • Step S1418 when it is determined that the autonomous adjustment is continued (Step S1418: Yes), the mobile terminal 221 moves to Step S1416.
  • step S1418: No the mobile terminal 221 stops the autonomous adjustment, resets the autonomous adjustment process (step S1419), and proceeds to step S1413.
  • the mobile terminal 221 starts autonomous adjustment when the moving speed of the local station exceeds the threshold Th_v1. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large. Further, the mobile terminal 221 stops the autonomous adjustment when the moving speed of the mobile station falls below the threshold Th_v2. Thereby, the autonomous adjustment can be stopped when the variation of the transmission timing deviation is small.
  • the mobile terminal 221 determines the autonomous transmission timing using the TA command received in the past separately from the adjustment of the transmission timing according to the TA command from the base station 211. Adjustments can be made. As a result, the number of TA command transmissions from the base station 211 can be reduced.
  • the mobile terminal 221 determines whether or not to adjust the autonomous transmission timing based on the moving speed of its own station. As the moving speed of the mobile terminal 221 is higher, the variation in the transmission timing deviation becomes larger. Accordingly, when the transmission timing deviation is large, autonomous adjustment can be performed to suppress the variation in the transmission timing deviation. Further, when adjusting the autonomous transmission timing, the mobile terminal 221 determines whether or not to continue the adjustment of the autonomous transmission timing based on the moving speed of the local station. Autonomous adjustment can be continued when fluctuations in transmission timing deviation are suppressed by autonomous adjustment.
  • FIG. 15A is a diagram of an example of a base station according to the fourth embodiment.
  • FIG. 15B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 15A. 15A and 15B, the same parts as those shown in FIGS. 4A and 4B are denoted by the same reference numerals, and description thereof is omitted.
  • the base station 211 according to the fourth embodiment includes a timer 844, a TA command accumulation unit 845, and an autonomous adjustment control determination process in addition to the configuration illustrated in FIGS. 4A and 4B.
  • a unit 846 and a parameter calculation unit 847 is a timer 844, a TA command accumulation unit 845, and an autonomous adjustment control determination process in addition to the configuration illustrated in FIGS. 4A and 4B.
  • the timer 844, the TA command accumulation unit 845, the autonomous adjustment control determination processing unit 846, and the parameter calculation unit 847 have the same configurations as those illustrated in FIGS. 8A and 8B.
  • the timing detection unit 438 outputs the TA command to the TA command accumulation unit 845.
  • the TA command accumulating unit 845 performs accumulative calculation processing of the TA command output from the timing detecting unit 438 for a certain time for each mobile terminal connected to the own station.
  • the parameter calculation unit 847 includes an instruction to start or stop autonomous adjustment (autonomous adjustment start / stop instruction) according to the determination result output from the autonomous adjustment control determination processing unit 846, the calculated parameter for autonomous adjustment, Is output to the scheduling processing unit 440.
  • the scheduling processing unit 440 performs scheduling so that the autonomous adjustment start / stop instruction and the parameter for autonomous adjustment output from the parameter calculation unit 847 are transmitted to the base station 211.
  • a physical channel such as PDSCH (Physical Downlink Shared Physical Channel) can be used to transmit an autonomous adjustment start / stop instruction and parameters for autonomous adjustment.
  • PDSCH Physical Downlink Shared Physical Channel
  • the timer 844, the TA command accumulation unit 845, the autonomous adjustment control determination processing unit 846, and the parameter calculation unit 847 can be realized by the digital circuit 401, for example.
  • FIG. 16A is a diagram illustrating an example of a mobile terminal according to the fourth embodiment.
  • FIG. 16B is a diagram illustrating an example of a signal flow in the mobile terminal illustrated in FIG. 16A. 16A and 16B, the same parts as those shown in FIGS. 8A and 8B are denoted by the same reference numerals, and description thereof is omitted.
  • the mobile terminal 221 according to the fourth embodiment includes the timer 844, the TA command accumulation unit 845, the autonomous adjustment control determination processing unit 846, and the parameter calculation unit 847 illustrated in FIGS. 8A and 8B. It is good also as a structure which excluded.
  • the receiving unit 843 outputs the parameter for autonomous adjustment transmitted from the base station 211 included in the received signal to the control unit 810.
  • the control unit 810 performs transmission timing control based on the parameters for autonomous adjustment output from the reception unit 843.
  • FIG. 17A and FIG. 17B are flowcharts illustrating an example of processing by the base station according to the fourth embodiment.
  • the base station 211 executes the steps shown in FIGS. 17A and 17B, for example, when communicating with the mobile terminal 221. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the base station 211 determines whether or not a TA command has been transmitted to the mobile terminal 221 (step S1701). When the TA command is not transmitted (step S1701: No), the base station 211 proceeds to step S1707. When the TA command is transmitted (step S1701: Yes), the base station 211 proceeds to step S1702.
  • the base station 211 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S1702). If autonomous adjustment is being performed (step S1702: Yes), the base station 211 performs transmission TA command accumulation processing for stop determination (step S1703), and proceeds to step S1707. In step S1703, the base station 211 adds the value of the TA command transmitted in step S1701 to the transmission TA command accumulated value for stop determination.
  • step S1702 when the autonomous adjustment is not being performed (step S1702: No), the base station 211 determines whether or not the autonomous adjustment start processing determination for the mobile terminal 221 has been started in step S1705 described later ( Step S1704). When the start process determination has been started (step S1704: Yes), the base station 211 proceeds to step S1706.
  • step S1704 if the start process determination has not been started (step S1704: No), the base station 211 activates an autonomous adjustment start determination timer (step S1705). Thereby, the start process determination of autonomous adjustment is started.
  • the start determination timer is a timer that measures the start determination timing of a predetermined cycle, for example.
  • step S1706 the base station 211 performs transmission TA command accumulation processing for start determination.
  • step S1706 the base station 211 adds the value of the TA command transmitted in step S1701 to the transmission TA command accumulated value for start determination.
  • the base station 211 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S1707).
  • step S1707 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S1707).
  • step S1708 determines whether or not the current time is the start timing of the autonomous adjustment (step S1708).
  • the determination in step S1708 can be made based on the start determination timer activated in step S1705, for example.
  • step S1708 when it is not the start timing of autonomous adjustment (step S1708: No), the base station 211 proceeds to step S1715.
  • step S1708: Yes the base station 211 compares the transmission TA command accumulated value for start determination with the threshold Th_TA3 (step S1709).
  • the base station 211 determines whether or not autonomous adjustment is required based on the comparison result in step S1709 (step S1710). For example, if the absolute value (cumulative value) of the transmission TA command cumulative value is larger than the threshold value Th_TA3, the base station 211 determines that autonomous adjustment is required, and the absolute value (cumulative value) of the transmission TA command cumulative value is equal to or less than the threshold value Th_TA3. If it is, it is determined that autonomous adjustment is not required.
  • step S1710 If it is determined in step S1710 that autonomous adjustment is not required (step S1710: No), the base station 211 proceeds to step S1714.
  • step S1710: Yes the base station 211 calculates parameters for autonomous adjustment (step S1711). Calculation of parameters for autonomous adjustment includes calculation of TA command change speed, determination of correction interval, and the like.
  • the calculation of the TA command change speed and the determination of the correction interval are the same as those performed by the mobile terminal 221 described above. For example, when parameters such as the moving speed of the mobile terminal 221 are used in determining the correction interval, the mobile terminal 221 notifies the base station 211 of the parameter, and the base station 211 uses the parameter notified from the mobile terminal 221. Can be used.
  • the base station 211 transmits an autonomous adjustment start instruction to the mobile terminal 221 (step S1712).
  • the base station 211 transfers the autonomous adjustment parameter (parameter) calculated in step S1711 to the mobile terminal 221 by storing the parameter in the autonomous adjustment start instruction, for example.
  • the mobile terminal 221 starts an autonomous adjustment process for adjusting transmission timing at a predetermined correction interval. That is, the mobile terminal 221 shifts to a state during autonomous adjustment.
  • the base station 211 activates the autonomous adjustment start timer and the autonomous adjustment stop determination timer, and also stops the autonomous adjustment start determination timer activated in step S1705 (step S1713).
  • the autonomous adjustment start timer is, for example, a timer that times the timing (correction interval) for executing autonomous adjustment.
  • the stop determination timer is, for example, a timer that measures stop determination timing of a predetermined cycle.
  • the base station 211 initializes a transmission TA command accumulated value for start determination (step S1714).
  • the base station 211 determines whether or not communication with the mobile terminal 221 is being continued (step S1715). When communication is continuing (step S1715: Yes), the base station 211 returns to step S1701. When communication is not continuing (step S1715: No), the base station 211 stops the autonomous adjustment, resets the autonomous adjustment process (step S1716), and ends the series of processes. In step S1716, the base station 211 may not perform the process of stopping the autonomous adjustment when the autonomous adjustment is not being performed.
  • step S1707 when the mobile terminal 221 is performing autonomous adjustment (step S1707: Yes), the base station 211 determines whether or not the current time is an autonomous adjustment stop determination timing (step S1717).
  • the determination in step S1717 can be made based on the stop determination timer started in step S1713, for example.
  • step S1717 when it is not the autonomous adjustment stop determination timing (step S1717: No), the base station 211 proceeds to step S1721.
  • step S1717: Yes the base station 211 compares the transmission TA command accumulated value with the threshold Th_TA4 (step S1718).
  • the threshold Th_TA4 is a threshold set separately from the threshold Th_TA3, for example, and may be the same as or different from the threshold Th_TA3.
  • the threshold value Th_TA4 can be a value equal to or greater than the threshold value Th_TA3.
  • the base station 211 determines whether or not the mobile terminal 221 continues the autonomous adjustment based on the comparison result in step S1718 (step S1719). For example, when the absolute value (cumulative value) of the transmission TA command accumulated value is smaller than the threshold Th_TA4, the base station 211 determines that the autonomous adjustment is continued, and the absolute value (cumulative value) of the transmission TA command accumulated value is the threshold Th_TA4. If it is above, it is determined that the autonomous adjustment is not continued.
  • step S1719 When it is determined in step S1719 that the autonomous adjustment is continued (step S1719: Yes), the base station 211 initializes a transmission TA command cumulative value for stop determination (step S1720). Then, the base station 211 causes the mobile terminal 221 to continue the autonomous adjustment (step S1721), and proceeds to step S1715. In addition, when the process for making the mobile terminal 221 continue autonomous adjustment is unnecessary, step S1721 may be omitted.
  • step S1719 If it is determined in step S1719 that the autonomous adjustment is not continued (step S1719: No), the base station 211 transmits an autonomous adjustment stop instruction to the mobile terminal 221 and resets the autonomous adjustment process (step S1722). . Then, the base station 211 moves to step S1715.
  • the base station 211 causes the mobile terminal 221 to start autonomous adjustment when the absolute value of the cumulative value of the TA command value within a certain time exceeds the threshold Th_TA3. Thereby, an autonomous adjustment can be started when the fluctuation
  • the base station 211 causes the mobile terminal 221 to continue the autonomous adjustment while the absolute value of the cumulative value of the TA command value within a certain time is below the threshold Th_TA4. Thereby, when the fluctuation
  • FIG. 18 is a flowchart of a modification of the process performed by the base station according to the fourth embodiment.
  • the base station 211 may execute the steps shown in FIG. 18 when communicating with the mobile terminal 221. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the base station 211 determines whether or not a TA command has been transmitted to the mobile terminal 221 (step S1801). If the TA command has not been transmitted (step S1801: No), the base station 211 proceeds to step S1815. When the TA command is transmitted (step S1801: Yes), the value of the transmitted TA command and the transmission time of the TA command are stored in the memory (step S1802).
  • the base station 211 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S1803).
  • autonomous adjustment is not being performed (step S1803: No)
  • past TA commands are accumulated starting from the transmitted TA command, and a time until the accumulated value reaches the threshold Th_TA3 is calculated (step S1804).
  • step S1804 the base station 211 calculates the length of the latest past period and the period during which the TA command whose accumulated value corresponds to the threshold value Th_TA3 is transmitted. For example, when the accumulated TA command accumulated value is small and the accumulated value does not reach the threshold Th_TA3, the calculation result in step S1804 can be set to ⁇ (infinity).
  • the base station 211 compares the threshold value Th_time3 with the time until the accumulated value calculated in step S1804 reaches the threshold value Th_TA3 (step S1805).
  • the base station 211 determines whether or not autonomous adjustment is required based on the comparison result in step S1805 (step S1806). For example, the base station 211 determines that autonomous adjustment is required if the time calculated in step S1804 is smaller than the threshold Th_time3, and determines that autonomous adjustment is not required if the time calculated in step S1804 is equal to or greater than the threshold Th_time3. .
  • step S1806 determines whether autonomous adjustment is not required (step S1806: No) or not required (step S1806: No). If it is determined in step S1806 that autonomous adjustment is not required (step S1806: No), the base station 211 proceeds to step S1810. If it is determined that autonomous adjustment is required (step S1806: YES), the base station 211 proceeds to step S1807. Steps S1807 and S1808 are the same as steps S1711 and S1712 shown in FIG. 17B.
  • step S1808 the base station 211 starts an autonomous adjustment start timer (step S1809).
  • the autonomous adjustment start timer is, for example, a timer that times the timing (correction interval) for executing autonomous adjustment.
  • the base station 211 moves to step S1810. Steps S1810 and S1811 are the same as steps S1715 and S1716 shown in FIG. 17B.
  • step S1803 when the autonomous adjustment is being performed (step S1803: Yes), the base station 211 proceeds to step S1812. That is, the base station 211 accumulates past TA commands starting from the transmitted TA command, and calculates the time until the accumulated value reaches the threshold Th_TA4 (step S1812).
  • step S1812 the base station 211 calculates the length of the most recent past period, in which the TA command whose accumulated value corresponds to the threshold value Th_TA4 is transmitted. For example, when the accumulated TA command accumulated value is small and the accumulated value does not reach the threshold Th_TA4, the calculation result in step S1812 can be set to ⁇ (infinity).
  • the base station 211 compares the threshold value Th_time4 with the time until the accumulated value calculated in step S1812 reaches the threshold value Th_TA4 (step S1813).
  • the base station 211 determines whether or not the mobile terminal 221 continues the autonomous adjustment based on the comparison result in step S1813 (step S1814). For example, the base station 211 determines to continue the autonomous adjustment when the time calculated in step S1812 is greater than the threshold Th_time4. In addition, the base station 211 determines that the autonomous adjustment is not continued when the time calculated in step S1812 is equal to or less than the threshold Th_time4.
  • step S1814 If it is determined in step S1814 that the autonomous adjustment is to be continued (step S1814: Yes), the base station 211 continues the autonomous adjustment (step S1815), and proceeds to step S1810. Note that step S1815 may be omitted when the process for continuing the autonomous adjustment is unnecessary.
  • step S1814 If it is determined in step S1814 that the autonomous adjustment is not continued (step S1814: No), the base station 211 transmits an autonomous adjustment stop instruction to the mobile terminal 221 and resets the autonomous adjustment process (step S1816). . Then, the base station 211 moves to step S1810.
  • the base station 211 starts autonomous adjustment when the time until the absolute value of the cumulative value of the TA command value reaches the threshold Th_TA3 falls below the threshold Th_time3. Thereby, an autonomous adjustment can be started when the variation of the transmission timing deviation is large.
  • the base station 211 can continue the autonomous adjustment while the absolute value of the cumulative value of the TA command value exceeds the threshold Th_time4 until the absolute value of the cumulative value of the TA command reaches the threshold Th_TA4. Thereby, when the fluctuation
  • FIG. 19 is a flowchart of an example of processing performed by the mobile terminal according to the fourth embodiment.
  • the mobile terminal 221 communicates with the base station 211, the mobile terminal 221 executes, for example, each step shown in FIG. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the mobile terminal 221 determines whether a TA command has been received from the base station 211 (step S1901). If the TA command has not been received (step S1901: NO), the mobile terminal 221 moves to step S1903. When the TA command is received (step S1901: Yes), the mobile terminal 221 adjusts the transmission timing of the local station using the received TA command value (step S1902). Next, the mobile terminal 221 determines whether it has received an autonomous adjustment start instruction or an autonomous adjustment stop instruction from the base station 211 (step S1903).
  • step S1903 when neither the autonomous adjustment start instruction nor the autonomous adjustment stop instruction is received (step S1903: No), the mobile terminal 221 maintains the autonomous adjustment state (step S1904), and the process proceeds to step S1908. To do.
  • step S1904 for example, the mobile terminal 221 continues the autonomous adjustment if the autonomous adjustment is being performed, and does not perform the autonomous adjustment as it is unless the autonomous adjustment is being performed.
  • step S1903 when an autonomous adjustment start instruction or an autonomous adjustment stop instruction is received (step S1903: Yes), the mobile terminal 221 determines whether the received instruction is an autonomous adjustment start instruction (step S1905). .
  • step S1905 when it is an autonomous adjustment start instruction (step S1905: Yes), the mobile terminal 221 starts autonomous adjustment (step S1906), and proceeds to step S1908.
  • step S1906 the mobile terminal 221 may reset processing related to autonomous adjustment.
  • the received instruction is not an autonomous adjustment start instruction but an autonomous adjustment stop instruction (step S1905: No)
  • the mobile terminal 221 stops the autonomous adjustment (step S1907), and proceeds to step S1908.
  • step S1907 the mobile terminal 221 may reset processing related to autonomous adjustment.
  • Steps S1908 and S1909 shown in FIG. 19 are the same as steps S916 and S917 shown in FIG. 9B.
  • the mobile terminal 221 can start autonomous adjustment of transmission timing based on an instruction from the base station 211, or can stop autonomous adjustment.
  • the same effect as in the second embodiment can be obtained.
  • the parameters for autonomous adjustment may be calculated by the mobile terminal 221 in the same manner as in the second embodiment when the mobile terminal 221 receives an autonomous adjustment start instruction from the base station 211.
  • FIG. 20A is a diagram of an example of a base station according to the fifth embodiment.
  • 20B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 20A. 20A and 20B, the same parts as those shown in FIG. 13A, FIG. 13B, FIG. 15A, and FIG.
  • the base station 211 according to the fifth embodiment includes a moving speed measurement unit 1301 instead of the TA command accumulation unit 845 illustrated in FIGS. 15A and 15B.
  • pilot signal demodulation section 437 outputs the demodulation result of the pilot signal to moving speed measurement section 1301.
  • the calculation method of the movement speed of the mobile terminal 221 by the movement speed measurement unit 1301 is the same as the calculation method by the mobile terminal 221 described above.
  • the moving speed measurement unit 1301 estimates the fading frequency between the mobile station 221 and the mobile station 221 based on the demodulation result of the pilot signal output from the pilot signal demodulation unit 437, and the mobile terminal based on the estimation result The moving speed of 221 is measured.
  • fading frequency estimation between the mobile terminal 221 and the base station 211 is not limited to the method using the demodulation result of the pilot signal, and various methods can be used.
  • the measurement of the moving speed of the base station 211 is not limited to the method using the estimation result of the fading frequency, and various methods such as a method using a GPS unit or an acceleration sensor can be used.
  • the moving speed measurement unit 1301 can obtain the mobile terminal 221 by notifying the mobile terminal 221 of information regarding the moving speed of the mobile terminal 221 obtained by a GPS unit, an acceleration sensor, or the like.
  • the autonomous adjustment control determination processing unit 846 Based on the timer value output from the timer 844, the autonomous adjustment control determination processing unit 846 compares the measurement result of the movement speed output from the movement speed measurement unit 1301 with a threshold value to determine whether or not the autonomous adjustment is necessary. Determine.
  • the configuration of the mobile terminal 221 according to the fifth embodiment can be the same as the configuration shown in FIGS. 16A and 16B, for example.
  • the process by the mobile terminal 221 according to the fifth embodiment can be the same as the process shown in FIG. 19, for example.
  • FIG. 21 is a flowchart of an example of processing by the base station according to the fifth embodiment.
  • the base station 211 according to the fifth embodiment executes, for example, each step illustrated in FIG. 21 when performing communication with the mobile terminal 221. In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the base station 211 calculates the moving speed of the mobile terminal 221 (step S2101). For example, the base station 211 calculates the moving speed of the mobile terminal 221 based on the notification information from the mobile terminal 221. Next, the base station 211 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S2102).
  • step S2102 when the autonomous adjustment is not being performed (step S2102: No), the base station 211 determines whether or not the autonomous adjustment start processing determination for the mobile terminal 221 has been started in step S2104 described later ( Step S2103). When the start process determination has been started (step S2103: Yes), the base station 211 proceeds to step S2105.
  • step S2103 if the start process determination has not been started (step S2103: No), the base station 211 starts an autonomous adjustment start determination timer (step S2104). Thereby, the start process determination of autonomous adjustment is started.
  • the start determination timer is a timer that measures the start determination timing of a predetermined cycle, for example.
  • the base station 211 determines whether or not the current time is an autonomous adjustment start determination timing (step S2105).
  • the determination in step S2105 can be performed based on the start determination timer activated in step S2104, for example.
  • step S2105 when it is not the start timing of autonomous adjustment (step S2105: No), the base station 211 proceeds to step S2111.
  • step S2105: Yes the base station 211 compares the moving speed calculated in step S2101 with the threshold Th_v3 (step S2106).
  • the base station 211 determines whether or not autonomous adjustment is required based on the comparison result in step S2106 (step S2107). For example, the base station 211 determines that autonomous adjustment is required when the moving speed is greater than the threshold Th_v3, and determines that autonomous adjustment is not required when the moving speed is equal to or less than the threshold Th_v3.
  • step S2107 If it is determined in step S2107 that autonomous adjustment is not required (step S2107: No), the base station 211 proceeds to step S2111. If it is determined that autonomous adjustment is required (step S2107: Yes), the base station 211 proceeds to step S2108. Steps S2108 to S2110 are the same as steps S1711 to S1713 shown in FIG. 17B. After step S2110, the base station 211 proceeds to step S2111. Steps S211 and S2112 are the same as steps S1715 and S1716 shown in FIG. 17B.
  • step S2102 when the mobile terminal 221 is performing autonomous adjustment (step S2102: Yes), the base station 211 determines whether or not the current time is an autonomous adjustment stop determination timing (step S2113).
  • the determination in step S2113 can be made based on, for example, the stop determination timer started in step S2110.
  • step S2113 when it is not the autonomous adjustment stop determination timing (step S2113: No), the base station 211 continues the autonomous adjustment (step S2114), and proceeds to step S2111. Note that step S2114 may be omitted when the process for continuing the autonomous adjustment is unnecessary.
  • step S2113 when it is the autonomous adjustment stop determination timing (step S2113: Yes), the base station 211 compares the movement speed calculated in step S2101 with the threshold Th_v4 (step S2115).
  • the threshold value Th_v4 is a threshold value set separately from the threshold value Th_v3, for example, and may be the same as or different from the threshold value Th_v3.
  • the base station 211 determines whether or not the mobile terminal 221 continues the autonomous adjustment based on the comparison result in step S2115 (step S2116). For example, the base station 211 determines that the autonomous adjustment is continued when the moving speed is greater than the threshold Th_v4, and determines that the autonomous adjustment is not continued when the moving speed is equal to or less than the threshold Th_v4.
  • step S2116 If it is determined in step S2116 that the autonomous adjustment is to be continued (step S2116: Yes), the base station 211 proceeds to step S2114. If it is determined not to continue the autonomous adjustment (step S2116: No), the base station 211 transmits an autonomous adjustment stop instruction to the mobile terminal 221 and resets the autonomous adjustment process (step S2117), and proceeds to step S2111. To do.
  • the base station 211 causes the mobile terminal 221 to start autonomous adjustment when the moving speed of the mobile terminal 221 exceeds a threshold Th_v3. Thereby, when the fluctuation
  • the same effect as in the third embodiment can be obtained.
  • the parameters for autonomous adjustment may be calculated by the mobile terminal 221 in the same manner as in the second embodiment when the mobile terminal 221 receives an autonomous adjustment start instruction from the base station 211.
  • FIG. 22A is a diagram of an example of a base station according to the sixth embodiment.
  • 22B is a diagram illustrating an example of a signal flow in the base station illustrated in FIG. 22A. 22A and 22B, parts that are the same as the parts shown in FIGS. 15A and 15B are given the same reference numerals, and descriptions thereof are omitted.
  • the base station 211 according to the sixth embodiment may be configured to omit the TA command accumulation unit 845 illustrated in FIGS. 15A and 15B.
  • the scheduling processing unit 440 notifies the autonomous adjustment control determination processing unit 846 of the number of mobile terminals accommodated by the base station 211 (the number of mobile terminals currently accommodated).
  • the autonomous adjustment control determination processing unit 846 determines whether or not autonomous adjustment is necessary by comparing the number of accommodated mobile terminals notified from the scheduling processing unit 440 with a threshold value.
  • the autonomous adjustment control determination processing unit 846 determines that autonomous adjustment is required when the number of accommodated mobile terminals exceeds a threshold value. Thereby, autonomous adjustment is performed in the mobile terminal 221, and the shift
  • FIG. 23 is a flowchart of an example of processing by the base station according to the sixth embodiment.
  • the base station 211 according to the sixth embodiment executes, for example, each step illustrated in FIG. 23 when performing communication with the base station 211.
  • the mobile terminal 221 In the initial state, it is assumed that the mobile terminal 221 is not performing autonomous adjustment.
  • the base station 211 calculates the number of mobile terminals accommodated by the mobile terminal 221 (step S2301). Next, the base station 211 determines whether or not the mobile terminal 221 is undergoing autonomous adjustment (step S2302). When the autonomous adjustment is not in progress (step S2302: No), the base station 211 determines whether or not the autonomous adjustment start process determination for the mobile terminal 221 has been started in step S2304 (step S2303). When the start process determination has been started (step S2303: Yes), the base station 211 proceeds to step S2305.
  • step S2303 when the start process determination has not been started (step S2303: No), the base station 211 activates an autonomous adjustment start determination timer (step S2304). Thereby, the start process determination of autonomous adjustment is started.
  • the start determination timer is a timer that measures the start determination timing of a predetermined cycle, for example.
  • the base station 211 determines whether or not the current time is an autonomous adjustment start determination timing (step S2305).
  • the determination in step S2305 can be made based on the start determination timer activated in step S2304, for example.
  • step S2305 when it is not the start timing of autonomous adjustment (step S2305: No), the base station 211 proceeds to step S2311.
  • step S2305: Yes the base station 211 compares the number of accommodated mobile terminals calculated in step S2301 with the threshold Th_n1 (step S2306).
  • the base station 211 determines whether or not autonomous adjustment is required based on the comparison result in step S2306 (step S2307). For example, the base station 211 determines that autonomous adjustment is required when the number of accommodated mobile terminals is greater than the threshold Th_n1, and determines that autonomous adjustment is not required when the number of accommodated mobile terminals is equal to or less than the threshold Th_n1.
  • step S2307 when it is determined that autonomous adjustment is not required (step S2307: No), the base station 211 proceeds to step S2311. If it is determined that autonomous adjustment is required (step S2307: Yes), the base station 211 proceeds to step S2308.
  • Steps S2308 to S2310 are the same as steps S1711 to S1713 shown in FIG. 17B. After step S2310, the base station 211 proceeds to step S2311.
  • Steps S2311, S2312 are the same as steps S1715, S1716 shown in FIG. 17B.
  • step S2302 when the mobile terminal 221 is performing autonomous adjustment (step S2302: Yes), the base station 211 determines whether or not the current time is an autonomous adjustment stop determination timing (step S2313). The determination in step S2313 can be made based on the stop determination timer activated in step S2310, for example.
  • step S2313 when it is not the autonomous adjustment stop determination timing (step S2313: No), the base station 211 continues the autonomous adjustment (step S2314), and proceeds to step S2311. Note that step S2314 may be omitted when the process for continuing the autonomous adjustment is unnecessary.
  • step S2313 when it is the autonomous adjustment stop determination timing (step S2313: Yes), the base station 211 compares the number of accommodated mobile terminals calculated in step S2301 with the threshold Th_n2 (step S2315).
  • the threshold Th_n2 is a threshold set separately from the threshold Th_n1, for example, and may be the same as or different from the threshold Th_n1.
  • the base station 211 determines whether or not to allow the mobile terminal 221 to continue the autonomous adjustment based on the comparison result in step S2315 (step S2316). For example, the base station 211 determines that the autonomous adjustment is continued when the number of accommodated mobile terminals is larger than the threshold Th_n2, and determines that the autonomous adjustment is not continued when the number of accommodated mobile terminals is equal to or less than the threshold Th_n2.
  • Step S2316 when it is determined that the autonomous adjustment is continued (Step S2316: Yes), the base station 211 proceeds to Step S2314. If it is determined not to continue the autonomous adjustment (step S2316: No), the base station 211 transmits an autonomous adjustment stop instruction to the mobile terminal 221 and resets the autonomous adjustment process (step S2317), and proceeds to step S2311. To do.
  • the base station 211 causes the mobile terminal 221 to start autonomous adjustment when the number of mobile terminals accommodated by the mobile terminal 221 exceeds a threshold Th_n1.
  • Th_n a threshold
  • the base station 211 causes the mobile terminal 221 to stop the autonomous adjustment when the number of mobile terminals accommodated by the mobile terminal 221 falls below the threshold Th_n2.
  • the mobile terminal 221 determines the autonomous transmission timing using the TA command received in the past, separately from the adjustment of the transmission timing according to the TA command from the base station 211. Adjustments can be made. As a result, the number of TA command transmissions from the base station 211 can be reduced.
  • the base station 211 determines whether or not to allow the mobile terminal 221 to adjust the autonomous transmission timing based on the number of mobile terminals accommodated in the own cell. Thereby, the throughput in the base station 211 can be improved.
  • the mobile terminal apparatus it is possible to reduce the number of transmissions of a signal instructing adjustment of transmission timing.
  • the propagation delay between a radio base station and a mobile terminal changes every moment. Therefore, while the radio base station and the mobile terminal are communicating, a TA command is transmitted from the radio base station to the mobile terminal periodically or irregularly using the downlink radio resource, and the UL signal is transmitted. Timing adjustment is performed.
  • a TA command is transmitted for each mobile terminal.
  • PDSCH is used as the physical channel of the downlink radio resource.
  • the PDSCH is also used for user data communication.
  • the TA command is transmitted to each mobile terminal, so that the amount of control data increases and the downlink radio resources that can be used for user data transmission decrease. For this reason, the throughput of the entire system is reduced.
  • UL signal transmission timing adjustment is autonomously performed in a mobile terminal using the most recently received TA command without receiving a TA command from a radio base station. Can be implemented. As a result, the number of TA command transmissions from the radio base station to the mobile terminal can be reduced. For example, it is possible to increase the transmission interval of TA commands periodically transmitted by the radio base station. In addition, the number of times that the radio base station transmits the TA command irregularly can be reduced according to the transmission timing shift of the mobile terminal.
  • the utilization efficiency of downlink radio resources can be improved. For example, since the number of TA command transmissions can be reduced, it is possible to increase downlink radio resources allocated to user data and improve throughput.

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

Abstract

　Selon l'invention, une unité de réception (112) reçoit, en provenance d'un dispositif de station de base (120), un signal d'instruction qui produit une instruction pour régler la temporisation à laquelle un signal sans fil est émis à partir d'une unité d'émission (111). Une unité de stockage (113) stocke une valeur de réglage correspondant au signal d'instruction reçu par l'unité de réception (112). Une unité de réglage (114) réalise un premier réglage de la temporisation d'émission qui correspond au signal d'instruction reçu par l'unité de réception (112). En outre, l'unité de réglage (114) réalise un second réglage de la temporisation d'émission sur la base de la valeur de stockée dans l'unité de stockage (113), le second réglage étant destiné à une période de temps différente de la période de temps pour le premier réglage.
PCT/JP2014/070953 2014-08-07 2014-08-07 Appareil de terminal mobile WO2016021033A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017154212A1 (fr) * 2016-03-11 2017-09-14 富士通株式会社 Système de communication sans fil, appareil terminal, appareil station de base et procédé de communication sans fil
CN113767663A (zh) * 2019-05-02 2021-12-07 株式会社Ntt都科摩 用户装置以及通信方法

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Publication number Priority date Publication date Assignee Title
JP2010028503A (ja) * 2008-07-22 2010-02-04 Yokogawa Electric Corp 無線通信システム
JP2011515991A (ja) * 2008-03-26 2011-05-19 クゥアルコム・インコーポレイテッド 加入者局におけるアップリンクフレーム同期のための方法および装置
WO2012056542A1 (fr) * 2010-10-28 2012-05-03 富士通株式会社 Dispositif de communications sans fil et procédé de communications sans fil

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JP2011515991A (ja) * 2008-03-26 2011-05-19 クゥアルコム・インコーポレイテッド 加入者局におけるアップリンクフレーム同期のための方法および装置
JP2010028503A (ja) * 2008-07-22 2010-02-04 Yokogawa Electric Corp 無線通信システム
WO2012056542A1 (fr) * 2010-10-28 2012-05-03 富士通株式会社 Dispositif de communications sans fil et procédé de communications sans fil

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017154212A1 (fr) * 2016-03-11 2017-09-14 富士通株式会社 Système de communication sans fil, appareil terminal, appareil station de base et procédé de communication sans fil
US10880849B2 (en) 2016-03-11 2020-12-29 Fujitsu Limited Radio communication system, terminal device, base station device and radio communication method
CN113767663A (zh) * 2019-05-02 2021-12-07 株式会社Ntt都科摩 用户装置以及通信方法

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