WO2018167984A1 - Dispositif de communication sans fil, système de communication sans fil et procédé de réglage de synchronisation de transmission - Google Patents

Dispositif de communication sans fil, système de communication sans fil et procédé de réglage de synchronisation de transmission Download PDF

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Publication number
WO2018167984A1
WO2018167984A1 PCT/JP2017/011059 JP2017011059W WO2018167984A1 WO 2018167984 A1 WO2018167984 A1 WO 2018167984A1 JP 2017011059 W JP2017011059 W JP 2017011059W WO 2018167984 A1 WO2018167984 A1 WO 2018167984A1
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WIPO (PCT)
Prior art keywords
signal
unit
reception
transmission
timing
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PCT/JP2017/011059
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English (en)
Japanese (ja)
Inventor
中谷　勇太
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富士通株式会社
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Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to JP2019505677A priority Critical patent/JP6866920B2/ja
Priority to PCT/JP2017/011059 priority patent/WO2018167984A1/fr
Publication of WO2018167984A1 publication Critical patent/WO2018167984A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/04—Speed or phase control by synchronisation signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements

Definitions

  • the present invention relates to a wireless communication device, a wireless communication system, and a transmission timing adjustment method.
  • a technique for synchronizing the time of each device with a standard time is known.
  • a wireless terminal that has received a standard time signal transmitted from a radio timepiece transmits standard time information to an access point.
  • the access point that has received the standard time signal updates its own time information with the received standard time information, and updates the time information of an NTP (Network Time Protocol) server in the network with the received standard time signal.
  • the NTP server updates the time information of other access points based on the updated time information.
  • Each access point updates the time information of the wireless terminal connected to the own device based on the time information of the own device. Thereby, the time information of each device in the wireless LAN system is synchronized with the standard time.
  • NTP Network Time Protocol
  • TDMA Time Division Multiple Access
  • CA Carrier Sense Multiple Access / Collision Avoidance
  • each device since each device transmits a signal at a transmission timing based on a reference signal that operates independently, the transmission timing of each device includes an error due to a frequency shift of the reference signal. Therefore, a guard period is provided between the slots transmitted from each device to absorb the transmission timing shift in each device. If the transmission timing difference between the devices is large, the guard period becomes longer, and the slot period allocated for data transmission becomes substantially shorter. Thereby, the data transmission efficiency decreases. Therefore, it is preferable to synchronize the transmission timing of each device with higher accuracy.
  • the disclosed technology has been made in view of the above points, and provides a wireless communication device, a wireless communication system, and a transmission timing adjustment method capable of synchronizing transmission timings between wireless communication devices with higher accuracy. For the purpose.
  • the wireless communication device disclosed in the present application includes an antenna, a transmission unit, a reception unit, a demodulation unit, a detection unit, and an adjustment unit.
  • the transmission unit transmits a transmission signal via the antenna.
  • the receiving unit receives the received signal via the antenna and converts the received signal from an analog signal to a digital signal.
  • the demodulator demodulates the control signal and user data included in the reception signal converted into the digital signal.
  • the detection unit detects the reception timing of the synchronization signal included in the reception signal converted into the digital signal.
  • the adjustment unit adjusts the transmission timing of the transmission signal by the transmission unit based on the detected reception timing.
  • the wireless communication device According to one aspect of the wireless communication device, the wireless communication system, and the transmission timing adjustment method disclosed in the present application, it is possible to synchronize the transmission timing between the wireless communication devices with higher accuracy.
  • FIG. 1 is a diagram illustrating an example of a wireless communication system.
  • FIG. 2 is a block diagram illustrating an example of an access point.
  • FIG. 3 is a diagram illustrating an example of the reception timing of the synchronization signal.
  • FIG. 4 is a block diagram illustrating an example of a wireless terminal.
  • FIG. 5 is a diagram illustrating an example of the position of a wireless terminal to which signals from a plurality of access points reach.
  • FIG. 6 is a diagram illustrating an example of the timing of data transmitted in time division.
  • FIG. 7 is a flowchart showing an example of the operation of the access point.
  • FIG. 8 is a flowchart illustrating an example of the operation of the wireless terminal.
  • FIG. 9 is a diagram illustrating an example of hardware of an access point.
  • FIG. 10 is a diagram illustrating an example of hardware of a wireless terminal.
  • FIG. 1 is a diagram illustrating an example of a wireless communication system 10.
  • the wireless communication system 10 includes a plurality of access points 20-1 to 20-2 and a wireless terminal 30.
  • Each of the access points 20-1 to 20-2 is connected to a network 11 such as a LAN (Local Area Network), for example, and performs wireless communication with the wireless terminal 30 based on the wireless LAN.
  • the access points 20-1 and 20-2 are collectively referred to as the access point 20 without being distinguished from each other.
  • the access point 20 is an example of a wireless communication device and a wireless base station.
  • the wireless communication system 10 may include three or more access points 20.
  • the wireless communication system 10 may include two or more wireless terminals 30.
  • the access point 20 transmits to the wireless terminal 30 by wireless communication.
  • the access point 20 sends data received from the wireless terminal 30 by wireless communication to the destination of the data via the network 11.
  • each access point 20 transmits and receives data to and from the wireless terminal 30 by wireless communication in a time slot allocated to the own device based on the TDMA method. Specifically, each access point 20 wirelessly transmits data to the wireless terminal 30 in the downlink signal time slot assigned to the access point 20. Each access point 20 receives data from the wireless terminal 30 in the time slot of the uplink signal assigned to the own device.
  • the downlink signal is a signal that is wirelessly transmitted from the access point 20 to the wireless terminal 30, and the uplink signal is a signal that is wirelessly transmitted from the wireless terminal 30 to the access point 20.
  • a different time slot is assigned to each access point 20 between adjacent access points 20. As a result, each access point 20 can transmit and receive data by wireless communication with the wireless terminal 30 without interfering with signals transmitted from other access points 20.
  • the wireless terminal 30 when the wireless terminal 30 receives a signal having a predetermined strength or more from the plurality of access points 20, the wireless terminal 30 transmits a synchronization signal.
  • the access point 20 that has received the synchronization signal transmitted from the wireless terminal 30 adjusts the transmission timing of the transmission signal to be transmitted to the wireless terminal 30 based on the reception timing of the transmitted synchronization signal.
  • wireless communications system 10 can adjust the transmission timing between the adjacent access points 20 with sufficient precision. Therefore, the guard period between time slots can be shortened, and the data transmission efficiency of the entire system can be improved.
  • FIG. 2 is a block diagram illustrating an example of the access point 20.
  • the access point 20 includes an antenna 21, an analog processing unit 22, and a digital processing unit 23.
  • the analog processing unit 22 includes a circulator 220, an analog transmission unit 221, and an analog reception unit 222.
  • the circulator 220 passes the transmission signal output from the analog transmission unit 221 to the antenna 21 and passes the reception signal received via the antenna 21 to the analog reception unit 222.
  • the analog transmission unit 221 includes a PA (Power Amplifier) 2210, an up-converter 2211, and a DAC (Digital to Analog Converter) 2212.
  • the DAC 2212 converts the transmission signal output from the digital processing unit 23 from a digital signal to an analog signal.
  • the up-converter 2211 performs processing such as orthogonal modulation and up-conversion on the transmission signal converted into an analog signal by the DAC 2212.
  • the PA 2210 amplifies the transmission signal that has been subjected to processing such as up-conversion by the up-converter 2211.
  • the transmission signal amplified by PA 2210 is output to circulator 220.
  • the analog reception unit 222 includes an LNA (Low Noise Amplifier) 2220, a down converter 2221, and an ADC (Analog to Digital Converter) 2222.
  • the LNA 2220 amplifies the reception signal received via the circulator 220.
  • the down converter 2221 performs processing such as orthogonal demodulation and down conversion on the reception signal amplified by the LNA 2220.
  • the ADC 2222 converts the received signal that has been subjected to processing such as down-conversion by the down converter 2221 from an analog signal to a digital signal.
  • the received signal converted into a digital signal by the ADC 2222 is output to the digital processing unit 23.
  • the analog receiving unit 222 is an example of a receiving unit.
  • the digital processing unit 23 includes a digital transmission processing unit 230, an adjustment unit 231, a holding unit 232, a calculation unit 233, a measurement unit 234, a detection unit 235, and a digital reception processing unit 236.
  • the digital transmission processing unit 230 generates a transmission signal by performing processing such as encoding and baseband modulation on the data received via the network 11. Then, the digital transmission processing unit 230 outputs the generated transmission signal to the analog processing unit 22 in accordance with the output timing instructed by the adjustment unit 231 in the downlink signal time slot assigned to the own device.
  • the transmission signal transmitted to the analog processing unit 22 is radiated from the antenna 21 to the space via the analog transmission unit 221 and the circulator 220.
  • the analog transmission unit 221 and the digital transmission processing unit 230 are an example of a transmission unit.
  • the digital transmission processing unit 230 is an example of a generation unit.
  • the digital reception processing unit 236 generates reception data by performing processing such as demodulation and decoding on the reception signal output from the analog processing unit 22 in the time slot of the uplink signal assigned to the own device. Then, the digital reception processing unit 236 outputs the generated reception data to the network 11 according to the destination of the reception data.
  • the digital reception processing unit 236 is an example of a demodulation unit.
  • the holding unit 232 performs processing related to processing from when the reception signal is received by the antenna 21 until the reception signal converted into the digital signal through the circulator 220 and the analog reception unit 222 is output to the digital processing unit 23.
  • Hold time ⁇ RF is an example of a first processing time.
  • the detection unit 235 detects the reception timing of the synchronization signal included in the reception signal output from the analog processing unit 22. Then, the detection unit 235 outputs information indicating the reception timing of the detected synchronization signal to the adjustment unit 231.
  • the synchronization signal is a known bit pattern signal composed of 0 and 1.
  • FIG. 3 is a diagram illustrating an example of the reception timing of the synchronization signal.
  • a synchronization signal is transmitted from the wireless terminal 30 at time t 0 as shown in FIG.
  • Time synchronization signal transmitted from the wireless terminal 30 propagates through the space between the wireless terminal 30 and the access point 20, for example, as shown in FIG. 3 (b), the propagation time tau Pr from time t 0 has elapsed It reaches the antenna 21 of the access point 20 at t 1 .
  • the synchronization signal that has reached the antenna 21 of the access point 20 is subjected to processing such as down-conversion in the analog receiver 222.
  • processing such as down-conversion in the analog receiver 222.
  • the synchronization signal is output to the digital processing unit 23 at time t 2 when the processing time ⁇ RF in the analog reception unit 222 has elapsed.
  • the detection unit 235 in the digital processing unit 23 starts receiving the synchronization signal at time t 2 , and detects the end of reception of the synchronization signal at time t 3 when the time length ⁇ S of the synchronization signal has elapsed. Then, the detection unit 235 detects a time t 2 that is back by the time length ⁇ S of the synchronization signal from the time t 3 when the end of reception of the synchronization signal is detected as a synchronization signal reception timing.
  • the detection unit 235 detects the reception timing of the inspection signal included in the signal output from the analog processing unit 22. Then, the detection unit 235 outputs information indicating the reception timing of the detected inspection signal to the measurement unit 234.
  • the inspection signal is a signal having a known bit pattern.
  • the inspection signal may be a signal having the same bit pattern as the synchronization signal, for example.
  • the adjustment unit 231 refers to the processing time ⁇ RF in the holding unit 232, and the time t that is traced by the processing time ⁇ RF from the reception timing of the synchronization signal 1 is specified as the reception timing of the synchronization signal.
  • the time that is back by the processing time ⁇ RF from the time t 2 detected by the detection unit 235 is the time t 1 when the synchronization signal reaches the antenna 21.
  • the adjustment unit 231 based on the time t 2 of the reception timing of the identified synchronization signal, the transmission signal from the antenna 21 to adjust the transmission timing is a timing that is transmitted. Then, the adjustment unit 231 adjusts the output timing of the transmission signal output from the digital transmission processing unit 230 to the analog processing unit 22 so that the transmission signal is transmitted from the antenna 21 at the adjusted transmission timing. Then, the adjustment unit 231 instructs the digital transmission processing unit 230 to output the transmission signal.
  • the measurement unit 234 measures the processing time ⁇ RF in the analog reception unit 222 at every predetermined timing. Specifically, the measurement unit 234 instructs the digital transmission processing unit 230 to generate a test signal and instructs the detection unit 235 to detect the reception timing of the test signal at every predetermined timing.
  • the inspection signal generated by the digital transmission processing unit 230 is output to the circulator 220 through the analog transmission unit 221 in the analog processing unit 22 as indicated by a broken line 40 in FIG.
  • a part of the inspection signal output from the analog transmission unit 221 to the circulator 220 leaks to the analog reception unit 222 as indicated by a broken line 40 in FIG.
  • the inspection signal leaked to the analog reception unit 222 is output to the digital processing unit 23 through the analog reception unit 222 as indicated by a broken line 40 in FIG.
  • the detection unit 235 detects the timing at which the inspection signal is received by the digital processing unit 23 as the reception timing of the inspection signal. Then, the detection unit 235 outputs information on the reception timing of the detected inspection signal to the measurement unit 234.
  • the measurement unit 234 measures the processing time ⁇ RF ′ from the timing at which the test signal is output from the digital transmission processing unit 230 to the analog processing unit 22 until the reception timing of the test signal detected by the detection unit 235.
  • the processing time ⁇ RF ′ is an example of a second processing time. Then, the measurement unit 234 outputs information of the measured processing time ⁇ RF ′ to the calculation unit 233.
  • Calculator 233 based on the processing time tau RF 'measured by the measuring unit 234 calculates the processing time tau RF analog receiver 222. Then, the calculation unit 233 causes the holding unit 232 to hold the calculated processing time ⁇ RF . Calculating unit 233, for example, 1/2 of the measured processing time tau RF 'by measuring unit 234 calculates the processing time tau RF analog receiver 222.
  • the time length ⁇ S of the synchronization signal is a fixed length, but the processing time ⁇ RF of the synchronization signal by the analog reception unit 222 is generally different for each access point 20.
  • the value of the processing time ⁇ RF held in the holding unit 232 is the processing time of the analog receiving unit 222 measured periodically by the measuring unit 234.
  • the adjustment unit 231 adjusts the transmission timing of the transmission signal based on a time t 1 that is a timing that is retroactive by the processing time ⁇ RF of the analog reception unit 222 from the time t 2 of the reception timing of the synchronization signal. Therefore, in the adjustment of the transmission timing, the influence of the processing time ⁇ RF of the analog reception unit 222 can be suppressed. Thereby, the adjustment unit 231 can accurately adjust the transmission timing of the transmission signal based on the time t 1 when the synchronization signal reaches the antenna 21.
  • the distance between the wireless terminal 30 and the access point 20 is about several tens of meters at the longest. Therefore, in a plurality of access points 20 that can receive radio waves transmitted from one wireless terminal 30, the difference in distance between the wireless terminal 30 and the access point 20 is about several tens of meters at the longest. Therefore, when a plurality of access points 20 receive one synchronization signal transmitted from one wireless terminal 30, the time difference between the synchronization signals reaching each access point 20 is less than 0.1 microseconds.
  • the transmission timing of each access point 20 is adjusted by adjusting the transmission timing of the transmission signal based on the time t 1 when the synchronization signal transmitted from the same wireless terminal 30 reaches the antenna 21.
  • the shift can be suppressed to less than 0.1 microsecond.
  • the access point 20 can adjust the transmission timing between the access points 20 with high accuracy.
  • the digital reception processing unit 236 performs processing such as demodulation and decoding of the control signal and user data.
  • the user data includes real-time data used for voice communication, videophone, and the like, and non-real-time data used for transferring data such as files.
  • the digital reception processing unit 236 processes signals and data included in the received signal with a priority according to each signal and data. Therefore, depending on the priority of processing, the time from when the signal is actually received until the processing ends may be different. This is because processing of low priority signals and data is postponed than processing of high priority signals and data. However, even in the case of a low priority signal or data, if a high priority signal or data is not received, the processing ends early.
  • the processing time of the synchronization signal changes depending on the presence / absence of other processing having a higher priority than the processing of the synchronization signal. Therefore, if the reception timing of the synchronization signal is detected by the digital reception processing unit 236, for example, as shown in FIG. 3E, the delay time ⁇ D until the synchronization signal processing is started is from 0 to a maximum of several tens. It will change in the order of milliseconds.
  • the maximum delay time ⁇ D is several tens of millimeters. Since there is a variation of about a second , it is difficult to accurately specify the time t2 at which reception of the synchronization signal is started.
  • the synchronization signal included in the reception signal is detected by the detection unit 235 provided separately from the digital reception processing unit 236.
  • the detection unit 235 does not process control signals or user data. Therefore, the detection unit 235 can accurately detect the timing at which the synchronization signal is output from the analog processing unit 22. Thereby, the adjustment unit 231 can accurately specify the timing at which the synchronization signal reaches the antenna 21.
  • Each access point 20 adjusts the transmission timing based on the timing when the synchronization signal reaches the antenna 21. Thereby, the access point 20 of a present Example can match
  • FIG. 4 is a block diagram illustrating an example of the wireless terminal 30.
  • the wireless terminal 30 includes an antenna 31, an analog processing unit 32, and a digital processing unit 33.
  • the analog processing unit 32 includes a circulator 320, an analog transmission unit 321, and an analog reception unit 322.
  • the circulator 320 passes the transmission signal output from the analog transmission unit 321 to the antenna 31 and passes the reception signal received via the antenna 31 to the analog reception unit 322.
  • the analog transmission unit 321 includes a PA 3210, an up-converter 3211, and a DAC 3212.
  • the DAC 3212 converts the transmission signal output from the digital processing unit 33 from a digital signal to an analog signal.
  • the up-converter 3211 performs processing such as quadrature modulation and up-conversion on the transmission signal converted into an analog signal by the DAC 3212.
  • the PA 3210 amplifies the transmission signal that has been subjected to processing such as quadrature modulation by the up-converter 3211.
  • the transmission signal amplified by PA 3210 is output to circulator 320.
  • the analog receiving unit 322 includes an LNA 3220, a down converter 3221, and an ADC 3222.
  • LNA 3220 amplifies the received signal received via circulator 320.
  • the down converter 3221 performs processing such as quadrature demodulation and down conversion on the reception signal amplified by the LNA 3220.
  • the ADC 3222 converts the reception signal that has been subjected to processing such as down-conversion by the down converter 3221 from an analog signal to a digital signal.
  • the received signal converted into a digital signal by the ADC 3222 is output to the digital processing unit 33.
  • the digital processing unit 33 includes a digital transmission processing unit 330, a synchronization signal control unit 331, and a digital reception processing unit 332.
  • the digital transmission processing unit 330 generates a transmission signal by performing processing such as encoding and baseband modulation on data generated by an application processing unit (not shown). Then, the digital transmission processing unit 330 outputs the generated transmission signal to the analog processing unit 32 in the uplink signal time slot assigned to the own device.
  • the transmission signal transmitted to the analog processing unit 32 is radiated from the antenna 31 to the space via the analog transmission unit 321 and the circulator 320.
  • the digital transmission processing unit 330 generates a synchronization signal when instructed by the synchronization signal control unit 331 to transmit a synchronization signal. Then, the digital transmission processing unit 330 outputs the generated synchronization signal to the analog processing unit 32 in the time slot of the upstream signal assigned to the own device.
  • the synchronization signal output to the analog processing unit 32 is radiated from the antenna 31 to the space via the analog transmission unit 321 and the circulator 320.
  • the digital reception processing unit 332 generates reception data by performing processing such as demodulation and decoding on the reception signal output from the analog processing unit 32 in the time slot of the downlink signal assigned to the own device. Then, the digital reception processing unit 332 outputs the generated reception data to an application processing unit (not shown).
  • the digital reception processing unit 332 monitors signals in time slots other than the time slot of the downlink signal assigned to the own device, and determines whether or not radio waves having a predetermined intensity or more are received from the plurality of access points 20. To do. If it is determined that radio waves having a predetermined intensity or more are received from the plurality of access points 20, the digital reception processing unit 332 is a signal indicating that radio waves having a predetermined intensity or more are received from the plurality of access points 20. Is output to the synchronization signal control unit 331.
  • the digital reception processing unit 332 is a signal indicating that radio waves having a predetermined intensity or higher are not received from the plurality of access points 20. Is output to the synchronization signal control unit 331.
  • the synchronization signal control unit 331 is at every predetermined timing (for example, every second).
  • the digital transmission processing unit 330 is instructed to transmit the synchronization signal.
  • wireless terminal 30 can transmit a synchronous signal with respect to the some access point 20, and can suppress the shift
  • the wireless terminal is located in an area where an area 29-1 capable of communicating with the access point 20-1 and an area 29-2 capable of communicating with the access point 20-2 overlap.
  • FIG. 5 is a diagram for explaining an example of the position of the wireless terminal 30 to which signals from a plurality of access points 20 reach.
  • the wireless terminal 30-1 is wirelessly communicating with the access point 20-1
  • the access point 20-2 is wirelessly communicating with the other wireless terminal 30-2.
  • each access point 20 and each wireless terminal 30 communicate using wireless signals having the same frequency in different time slots.
  • Each access point 20 wirelessly transmits a downlink signal to the wireless terminal 30 in a time slot assigned to each access point 20.
  • the access point 20-1 wirelessly transmits a downlink signal to the wireless terminal 30-1 in the time slot 51-1.
  • FIG. 6 is a diagram illustrating an example of the timing of data transmitted in time division.
  • the access point 20-2 wirelessly transmits a downlink signal to the other wireless terminal 30-2 in the time slot 51-2.
  • a GI (Guard Interval) 50 that is a period during which no signal is transmitted is provided between adjacent time slots.
  • the wireless terminal 30-1 that has received signals from the plurality of access points 20 transmits a synchronization signal.
  • the access point 20-1 and the access point 20-2 receive the synchronization signal transmitted from the wireless terminal 30-1, and adjust the transmission timing based on the received synchronization signal. Thereby, the shift
  • the transmission timing shift at each access point 20 is reduced, and for example, as shown in FIG. 6B, the GI 50 'can be shortened. Thereby, the transmission efficiency as the whole radio
  • FIG. 7 is a flowchart showing an example of the operation of the access point 20.
  • the access point 20 starts the operation shown in this flowchart at a predetermined timing such as when the power is turned on. Note that time slot assignments respectively used for downlink signal transmission and uplink signal reception are set in advance in each access point 20 by a higher-level device or the like connected to the network 11.
  • the measurement unit 234 measures the processing time ⁇ RF ′ in the analog reception unit 222 (S100). Specifically, the measurement unit 234 instructs the digital transmission processing unit 230 to generate a test signal and instructs the detection unit 235 to detect the reception timing of the test signal.
  • the digital transmission processing unit 230 generates a test signal and outputs the generated test signal to the analog processing unit 22.
  • the inspection signal is output to the detection unit 235 via the analog transmission unit 221, the circulator 220, and the analog reception unit 222.
  • the detection unit 235 detects the timing at which the inspection signal is received by the digital processing unit 23 as the reception timing of the inspection signal.
  • the measurement unit 234 measures the time from the timing at which the test signal is output from the digital transmission processing unit 230 to the analog processing unit 22 to the reception timing of the test signal detected by the detection unit 235 as the processing time ⁇ RF ′.
  • step S100 is performed in a time slot assigned to the own apparatus and during which communication with the wireless terminal 30 is not performed.
  • the computing unit 233 based on the processing time tau RF 'measured by the measuring unit 234 calculates the processing time tau RF analog receiving section 222 (S101).
  • Calculating unit 233 for example, 1/2 of the measured processing time tau RF 'by measuring unit 234 calculates the processing time tau RF analog receiver 222.
  • the calculation unit 233 causes the holding unit 232 to hold the calculated processing time ⁇ RF .
  • the measurement unit 234, the value of the timer t a for measuring the period for calculating the RF processing time ⁇ are initialized to 0 (S102).
  • the digital transmission processing unit 230 determines whether or not it is the time slot timing of the downlink signal assigned to the own device (S103). When it is the time slot timing of the downlink signal assigned to the own apparatus (S103: Yes), the digital transmission processing unit 230 executes the downlink signal transmission process (S104). In the downlink signal transmission process, if there is data to be transmitted to the wireless terminal 30, the digital transmission processing unit 230 generates a transmission signal based on the data. The transmission signal generated by the digital transmission processing unit 230 is transmitted to the wireless terminal 30 via the analog processing unit 22 and the antenna 21. Then, the digital transmission processing unit 230 executes the process shown in step S103 again.
  • the detection unit 235 determines whether it is the timing of the time slot of the uplink signal assigned to the own device (S105). ). If it is not the time slot timing of the uplink signal assigned to the own device (S105: No), the digital transmission processing unit 230 executes the process shown in step S103 again.
  • the detection unit 235 determines whether or not a synchronization signal has been received (S106).
  • the digital reception processing unit 236 performs uplink signal reception processing (S107).
  • the digital reception processing unit 236 demodulates and decodes the reception signal output from the analog processing unit 22 to generate reception data.
  • the reception data generated by the digital reception processing unit 236 is output to the network 11 according to the destination of the reception data. Then, the digital transmission processing unit 230 executes the process shown in step S103 again.
  • the detection unit 235 detects the time t 2 of the reception timing of the synchronization signal. Then, the detection unit 235 outputs information indicating the detected reception timing time t 2 to the adjustment unit 231.
  • the adjustment unit 231 acquires the processing time ⁇ RF of the analog reception unit 222 from the holding unit 232. Then, the adjustment unit 231 specifies a time t 1 that is retroactive by the processing time ⁇ RF from the time t 2 of the synchronization signal reception timing as the synchronization signal reception timing (S108).
  • the adjustment unit 231 adjusts the transmission timing of the transmission signal based on the time t 1 of the reception timing of the synchronization signal (S109). Then, the adjustment unit 231 adjusts the output timing of the transmission signal output from the digital transmission processing unit 230 to the analog processing unit 22 so that the transmission signal is transmitted from the antenna 21 at the adjusted transmission timing. Then, the adjustment unit 231 instructs the digital transmission processing unit 230 to output the transmission signal.
  • the detection unit 235 initializes, to 0, the value of the timer t b for measuring the adjustment period of the transmission timing (S110). Then, the digital reception processing unit 236 executes uplink signal reception processing (S111).
  • the detection unit 235 determines whether or not the value of the timer t b has exceeded a predetermined threshold value t th1 (S112).
  • the threshold t th1 is a value corresponding to 1 second, for example. If the value of the timer t b is the threshold value t th1 following (S112: No), the digital transmission processor 230 and the digital reception processing unit 236 performs transmission and reception processing (S113). In the transmission / reception processing, the digital transmission processing unit 230 transmits a transmission signal in the time slot of the downlink signal, and the digital reception processing unit 236 receives the reception signal in the time slot of the uplink signal. And the detection part 235 performs the process shown to step S112 again.
  • the measurement unit 234 determines whether or not the value of the timer t a exceeds a predetermined threshold t th2 (S114).
  • the threshold value t th2 is a value corresponding to several hours to several days, for example. If the value of the timer t a is the threshold value t th2 following (S114: No), the digital transmission processing unit 230 executes again the process shown in step S103. On the other hand, if the value of the timer t a exceeds the threshold value t th2 (S114: Yes), the measurement unit 234 executes again the process shown in step S100.
  • FIG. 8 is a flowchart illustrating an example of the operation of the wireless terminal 30.
  • the wireless terminal 30 starts the operation shown in this flowchart at a predetermined timing such as when the power is turned on.
  • the wireless terminal 30 receives the downlink signal transmitted from the access point 20 in the time slot designated by the access point 20 to which the wireless terminal 30 belongs, and the uplink to the access point 20 A signal is being transmitted.
  • the digital reception processing unit 332 monitors signals in time slots other than the time slot of the downlink signal assigned to the own device, and determines whether or not radio waves having a predetermined intensity or more are received from a plurality of access points 20. (S200). When the radio wave having a predetermined intensity or higher is not received from the plurality of access points 20 (S200: No), the digital reception processing unit 332 indicates that the radio wave having a predetermined intensity or higher is not received from the plurality of access points 20. Is output to the synchronization signal control unit 331. Then, the digital reception processing unit 332 executes the process shown in step S200 again.
  • the digital reception processing unit 332 indicates that radio waves having a predetermined intensity or higher are being received from the plurality of access points 20.
  • the signal shown is output to the synchronization signal control unit 331.
  • the synchronization signal control unit 331 initializes the value of the timer t c for measuring the transmission period of the synchronization signal to 0 (S201). Then, the synchronization signal control unit 331 instructs the digital transmission processing unit 330 to transmit the synchronization signal.
  • the digital transmission processing unit 330 generates a synchronization signal, and outputs the generated synchronization signal to the analog processing unit 32 in the time slot of the uplink signal assigned to the own device.
  • the synchronization signal output from the digital transmission processing unit 330 to the analog processing unit 32 is transmitted from the antenna 31 via the analog transmission unit 321 and the circulator 320 (S202).
  • the digital reception processing unit 332 monitors signals in time slots other than the time slot of the downlink signal assigned to the own device, and determines whether or not radio waves having a predetermined intensity or more are received from the plurality of access points 20. Determination is made (S203). When radio waves having a predetermined intensity or more are received from a plurality of access points 20 (S203: Yes), the digital reception processing unit 332 indicates that a radio wave having a predetermined intensity or more is received from the plurality of access points 20. Is output to the synchronization signal control unit 331.
  • the synchronization signal control unit 331 determines whether or not the value of the timer t c has exceeded a predetermined threshold value t th3 (S204).
  • the threshold value t th3 is a value corresponding to 1 second, for example.
  • the digital reception processing unit 332 executes the process shown in step S203 again.
  • the synchronization signal control unit 331 executes the process shown in step S201 again.
  • the digital reception processing unit 332 confirms that radio waves having a predetermined intensity or higher are not received from the plurality of access points 20.
  • the signal shown is output to the synchronization signal control unit 331. Then, the digital reception processing unit 332 executes the process shown in step S200 again.
  • FIG. 9 is a diagram illustrating an example of hardware of the access point 20.
  • the access point 20 includes a wireless communication circuit 200, a processor 201, a memory 202, a communication interface 203, and an antenna 21.
  • the wireless communication circuit 200 performs predetermined processing such as modulation on the signal output from the processor 201 and transmits the processed transmission signal via the antenna 21.
  • Radio communication circuit 200 performs predetermined processing such as demodulation on the received signal received via antenna 21 and outputs the result to processor 201.
  • the wireless communication circuit 200 implements the function of the analog processing unit 22, for example.
  • the communication interface 203 is an interface for connecting to the network 11 by wired connection.
  • the memory 202 stores programs for realizing the functions of the digital transmission processing unit 230, the adjustment unit 231, the calculation unit 233, the measurement unit 234, the detection unit 235, and the digital reception processing unit 236.
  • the memory 202 stores data in the holding unit 232 and the like.
  • the processor 201 reads out the program from the memory 202 and executes the program, for example, the digital transmission processing unit 230, the adjustment unit 231, the holding unit 232, the calculation unit 233, the measurement unit 234, the detection unit 235, and the digital reception processing unit 236. Each function is realized.
  • a program is stored in a portable recording medium such as a memory card inserted into the access point 20, and the access point 20 acquires and executes a part of the program used for processing from such a portable recording medium. May be.
  • the access point 20 may acquire and execute the program from another computer or server device that stores the program via a wireless communication line, a public line, the Internet, a LAN, a WAN, or the like.
  • FIG. 10 is a diagram illustrating an example of hardware of the wireless terminal 30.
  • the wireless terminal 30 includes a wireless communication circuit 300, a processor 301, a memory 302, and an antenna 31.
  • the wireless communication circuit 300 performs predetermined processing such as modulation on the signal output from the processor 301, and transmits the processed transmission signal via the antenna 31. In addition, the wireless communication circuit 300 performs predetermined processing such as demodulation on the reception signal received via the antenna 31 and outputs the result to the processor 301.
  • the wireless communication circuit 300 implements the function of the analog processing unit 32, for example.
  • the memory 302 stores programs for realizing the functions of the digital transmission processing unit 330, the synchronization signal control unit 331, and the digital reception processing unit 332, and the like.
  • the processor 301 reads out and executes a program from the memory 302, thereby realizing the functions of the digital transmission processing unit 330, the synchronization signal control unit 331, and the digital reception processing unit 332.
  • the program is stored in a portable recording medium such as a memory card inserted into the wireless terminal 30, and the wireless terminal 30 acquires and executes a part of the program used for processing from such a portable recording medium. May be.
  • the wireless terminal 30 may acquire and execute the program from another computer or server device storing the program via a wireless communication line, a public line, the Internet, a LAN, a WAN, or the like.
  • the wireless communication system 10 includes a plurality of access points 20 and wireless terminals 30.
  • the wireless terminal 30 transmits a synchronization signal to each of the plurality of access points 20.
  • Each access point 20 includes an antenna 21, an analog transmission unit 221, an analog reception unit 222, a digital reception processing unit 236, a detection unit 235, and an adjustment unit 231.
  • the analog transmission unit 221 transmits a transmission signal via the antenna 21.
  • the analog reception unit 222 receives a reception signal via the antenna 21 and converts the reception signal from an analog signal to a digital signal.
  • the digital reception processing unit 236 demodulates the control signal and user data included in the reception signal converted into the digital signal.
  • the detection unit 235 detects the reception timing of the synchronization signal included in the reception signal converted into the digital signal.
  • the adjustment unit 231 adjusts the transmission timing of the transmission signal by the analog processing unit 22 based on the reception timing of the synchronization signal. Thereby, the radio
  • the access point 20 performs processing from when the analog reception unit 222 receives a reception signal via the antenna 21 until the reception signal converted into a digital signal is output to the adjustment unit 231.
  • a holding unit 232 that holds the time ⁇ RF is included.
  • the adjustment unit 231 adjusts the transmission timing of the transmission signal to a timing that is retroactive to the processing time ⁇ RF from the reception timing detected by the detection unit 235. Thereby, it is possible to suppress the influence of variations in delay time of the analog reception unit 222 at the transmission timing. Thereby, the radio
  • the access point 20 includes the analog transmission unit 221, the digital transmission processing unit 230, the circulator 220, the measurement unit 234, and the calculation unit 233.
  • the digital transmission processing unit 230 generates a digital signal transmission signal.
  • the analog transmission unit 221 converts a digital transmission signal into an analog signal and transmits the analog signal via the antenna 21.
  • the circulator 220 passes the transmission signal transmitted from the analog transmission unit 221 to the antenna 21 and passes the reception signal received via the antenna 21 to the analog reception unit 222.
  • the measurement unit 234 is configured to allow the transmission signal output from the analog transmission unit 221 to leak to the analog reception unit 222 via the circulator 220, be converted into a digital signal by the analog reception unit 222, and be output to the detection unit 235.
  • Calculator 233 calculates the processing time tau RF on the basis of the processing time tau RF 'measured by the measuring unit 234, and holds the calculated processing time tau RF to the holding portion 232. Thereby, the access point 20 calculates the processing time ⁇ RF of the analog reception unit 222 based on the actual delay time measurement results of the analog transmission unit 221 and the analog reception unit 222. Thereby, the radio
  • the measuring unit 234 measures the processing time ⁇ RF ′ at every predetermined timing.
  • the calculation unit 233 updates the processing time ⁇ RF held in the holding unit 232 based on the measured processing time ⁇ RF ′.
  • the access point 20 can update the processing time ⁇ RF of the analog reception unit 222 in accordance with a change in the characteristics of the analog reception unit 222 due to an environmental change, a secular change, or the like.
  • wireless communications system 10 can synchronize the transmission timing between the access points 20 with a higher precision.
  • wireless communication in a wireless LAN has been described as an example.
  • the disclosed technology is not limited to this, and can be applied to a system that performs TDMA wireless communication.
  • the processing blocks of the access point 20 and the wireless terminal 30 function according to the main processing contents in order to facilitate understanding of the access point 20 and the wireless terminal 30 in the embodiment. It is classified separately. For this reason, the disclosed technique is not limited by the processing block classification method and its name.
  • each processing block included in each of the access point 20 and the wireless terminal 30 in the above-described embodiment can be subdivided into a larger number of processing blocks according to the processing content, or a plurality of processing blocks can be divided into one processing block. Can also be integrated.
  • the processing executed by each processing block may be realized as software processing, or may be realized by dedicated hardware such as ASIC (Application Specific Integrated Circuit).
  • wireless communication system 11 network 20 access point 21 antenna 22 analog processing unit 220 circulator 221 analog transmission unit 222 analog reception unit 23 digital processing unit 230 digital transmission processing unit 231 adjustment unit 232 holding unit 233 calculation unit 234 measurement unit 235 detection unit 236 Digital reception processing unit 30 Wireless terminal 31 Antenna 32 Analog processing unit 320 Circulator 321 Analog transmission unit 322 Analog reception unit 33 Digital processing unit 330 Digital transmission processing unit 331 Synchronization signal control unit 332 Digital reception processing unit

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

L'invention porte sur un dispositif de communication sans fil (20) comprenant une antenne (21), une unité de transmission (221), une unité de réception (222), une unité de démodulation (236), une unité de détection (235) et une unité de réglage (231). L'unité de transmission transmet un signal de transmission par l'intermédiaire de l'antenne. L'unité de réception reçoit un signal de réception par l'intermédiaire de l'antenne, et convertit le signal de réception d'un signal analogique en un signal numérique. L'unité de démodulation démodule un signal de commande et des données d'utilisateur qui sont incluses dans le signal de réception qui a été converti en signal numérique. L'unité de détection détecte la synchronisation de réception d'un signal de synchronisation inclus dans le signal de réception qui a été converti en signal numérique. L'unité de réglage règle la synchronisation de transmission du signal de transmission à partir de l'unité de transmission sur la base de la synchronisation de réception détectée.
PCT/JP2017/011059 2017-03-17 2017-03-17 Dispositif de communication sans fil, système de communication sans fil et procédé de réglage de synchronisation de transmission WO2018167984A1 (fr)

Priority Applications (2)

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JP2019505677A JP6866920B2 (ja) 2017-03-17 2017-03-17 無線通信装置、無線通信システム、および送信タイミング調整方法
PCT/JP2017/011059 WO2018167984A1 (fr) 2017-03-17 2017-03-17 Dispositif de communication sans fil, système de communication sans fil et procédé de réglage de synchronisation de transmission

Applications Claiming Priority (1)

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PCT/JP2017/011059 WO2018167984A1 (fr) 2017-03-17 2017-03-17 Dispositif de communication sans fil, système de communication sans fil et procédé de réglage de synchronisation de transmission

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000013850A (ja) * 1998-06-19 2000-01-14 Hitachi Ltd 通信装置、基地局および通信方法
WO2006090457A1 (fr) * 2005-02-24 2006-08-31 Mitsubishi Denki Kabushiki Kaisha Station de base d'un systeme de communication mobile
US20090207954A1 (en) * 2008-02-19 2009-08-20 Innovative Cocepts, Inc. Mimo slotted aloha (msa) system
JP2014039149A (ja) * 2012-08-16 2014-02-27 Nippon Hoso Kyokai <Nhk> 無線通信装置、方法及びプログラム

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000013850A (ja) * 1998-06-19 2000-01-14 Hitachi Ltd 通信装置、基地局および通信方法
WO2006090457A1 (fr) * 2005-02-24 2006-08-31 Mitsubishi Denki Kabushiki Kaisha Station de base d'un systeme de communication mobile
US20090207954A1 (en) * 2008-02-19 2009-08-20 Innovative Cocepts, Inc. Mimo slotted aloha (msa) system
JP2014039149A (ja) * 2012-08-16 2014-02-27 Nippon Hoso Kyokai <Nhk> 無線通信装置、方法及びプログラム

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