WO2014020714A1 - Procédé pour l'exécution d'une synchronisation temporelle dans un système de réseau sans fil - Google Patents

Procédé pour l'exécution d'une synchronisation temporelle dans un système de réseau sans fil Download PDF

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Publication number
WO2014020714A1
WO2014020714A1 PCT/JP2012/069536 JP2012069536W WO2014020714A1 WO 2014020714 A1 WO2014020714 A1 WO 2014020714A1 JP 2012069536 W JP2012069536 W JP 2012069536W WO 2014020714 A1 WO2014020714 A1 WO 2014020714A1
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Prior art keywords
time synchronization
wireless
terminal
packet
time
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PCT/JP2012/069536
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English (en)
Japanese (ja)
Inventor
悠一 五十嵐
和也 門田
原田　諭
中野　亮
小泉　稔
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株式会社日立製作所
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Priority to PCT/JP2012/069536 priority Critical patent/WO2014020714A1/fr
Priority to JP2014527884A priority patent/JP5868506B2/ja
Publication of WO2014020714A1 publication Critical patent/WO2014020714A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/002—Mutual synchronization

Definitions

  • the present invention relates to time synchronization in wireless multi-hop communication.
  • the wireless terminal uses the wireless communication by multicast transmission of the time information held by the own terminal at a predetermined cycle, and updates when the surrounding terminals receiving the information are newer than the time information held by the own terminal.
  • a method for realizing time synchronization (Patent Document 1).
  • the wireless terminal (slave) transmits a time request packet to the terminal (master) that wants time synchronization, and receives a time synchronization response packet from the terminal.
  • there is a method for realizing time synchronization (Patent Document 2).
  • there is a method of realizing synchronization by using a transmission / reception delay error of normal upper direction and lower direction data communication without using time synchronization information Patent Document 3).
  • the timing for performing time synchronization adjustment depends on the number of data communications, so the number of times wireless multihop transfer processing is performed, that is, data communications performed by each terminal. Since the number of times is not uniform throughout the system, it is difficult to match the synchronization accuracy of the entire wireless system.
  • An object of the present invention is to realize that the synchronization accuracy of each wireless terminal is kept constant throughout the system in a data collection system in which terminal information in the network is collected by wireless communication.
  • the present invention has the following configuration.
  • all wireless terminals are time synchronized by wireless communication.
  • a data communication response confirmation packet or a time synchronization information request packet and its response packet are used appropriately and used to synchronize with the parent terminal of the terminal itself.
  • time synchronization is performed with a data communication response confirmation packet at a place where constant data communication traffic occurs (between terminals), and time synchronization communication is performed at a place where constant data communication traffic does not occur.
  • the synchronization accuracy of the wireless terminal can be maintained with higher accuracy.
  • the wireless communication system configuration and the wireless packet configuration will be described with reference to FIGS. Next, an outline of the operation of the time synchronization process in the wireless communication system will be described with reference to FIGS.
  • FIG. 1 is an overall configuration diagram of a wireless communication system according to the present embodiment.
  • the wireless network 100 includes a gateway 101, a wireless relay terminal (Node A) 102, a wireless relay terminal (Node B) 103, a wireless relay terminal (Node C) 104, a wireless terminal (Node D) 105, and a wireless relay terminal (Node E).
  • 106 wireless relay terminal (node F) 107, wireless terminal (node H) 108, wireless terminal (node I) 109, wireless terminal (node J) 110, wireless terminal (node (K)) 111, wireless terminal (node G) 112).
  • a dotted line connecting each wireless terminal in the wireless network 101 indicates a communication path capable of wireless communication.
  • FIG. 2 is a hardware configuration diagram of a wireless terminal and a wireless relay terminal that configure the wireless communication system according to the present embodiment.
  • the wireless relay terminal and the wireless terminal are the same hardware. These are determined by the network topology in the wireless multi-hop network. For convenience, when there is another node below the own node, it is called a wireless relay terminal, and when the own node is a terminal, it is called a wireless terminal.
  • the wireless terminal / wireless relay terminal 201 is an embedded device having a wireless communication function with the wireless terminal gateway, and includes a microcomputer 202, a clock generation circuit 209, a power supply circuit 210, and an RF peripheral circuit 211.
  • the microcomputer 202 includes a ROM 203 and a RAM 208, and is connected to a power supply circuit 210, a clock generation circuit 209, and an RF peripheral circuit 211.
  • the ROM 203 is a storage device composed of a read-only semiconductor memory or the like, and is composed of a central control unit 204, a time synchronization control unit 205, a path management unit 206, and a wireless communication processing unit 207, and is connected to the RAM 208. .
  • the central control unit 204 controls execution of a program in the ROM, and is connected to the time synchronization control unit 205, the wireless communication processing unit 207, and the route management unit 206.
  • the time synchronization control unit 205 realizes a function to synchronize with the time transmitted from the wireless terminal gateway which is a time base station, and adjusts the progress of the clock using the received synchronization time information, The timing for requesting information is determined.
  • the route management unit 206 manages routes in multi-hop communication between terminals in the network.
  • the wireless communication processing unit 207 realizes transmission / reception processing in wireless communication. Specifically, packet assembly processing such as designation of the transmission destination and hop number when transmitting, and packet analysis processing such as determination of whether or not the packet is a self-destination packet when receiving are performed.
  • a frame storage unit 212 is connected.
  • a RAM 208 is a storage device such as a rewritable semiconductor memory element, is used as a transmission / reception buffer in wireless communication, and is connected to the ROM 203.
  • the clock generation circuit 209 is a circuit that generates a clock used in the microcomputer and the RF peripheral circuit, and is connected to the power supply circuit 210, the microcomputer 202, and the RF peripheral circuit 211.
  • the power supply circuit 210 supplies power to the wireless terminal / wireless relay terminal itself, and is connected to the clock generation circuit 209, the microcomputer 202, and the RF peripheral circuit 211.
  • the RF peripheral circuit 211 is a circuit that transmits and receives radio signals, and is connected to the power supply circuit 210, the clock generation circuit 209, and the microcomputer 202.
  • the wireless terminal / wireless relay terminal 201 may be an independent device instead of an embedded device.
  • FIG. 3 is a hardware configuration diagram of a wireless gateway constituting the wireless communication system according to the present embodiment.
  • the gateway wireless terminal 301 is a device that communicates with a wireless communication function with a wireless terminal / wireless relay terminal and a device connected to an external network and realizes a connection between the wireless network and the external network.
  • the device includes an external network connection circuit 312.
  • the external network connection circuit 312 is a circuit that realizes a function for using an external network such as Ethernet (registered trademark), WiFi (registered trademark), an optical line, and a telephone network.
  • the 4 (A) to 4 (D) are wireless packet configuration diagrams according to the present embodiment. These packets are a data communication packet 401, a data confirmation response packet 402, a time synchronization information request packet 403, and a time synchronization information distribution packet 404, respectively.
  • the data communication packet 401 is a packet for transmitting data from a certain wireless terminal / wireless relay terminal to another wireless terminal / wireless relay terminal in response to a request for application or the like.
  • the data confirmation response packet 402 is a packet for confirming that the wireless terminal / wireless relay terminal that has received the data communication packet 401 has received the packet to the wireless terminal / wireless relay terminal that has transmitted the packet.
  • the time synchronization information request packet 403 is a packet when a certain wireless terminal / wireless relay terminal requests time information from another wireless terminal / wireless relay terminal.
  • the time synchronization information distribution packet 404 is transmitted when the wireless terminal / wireless relay terminal that has received the time synchronization information request packet transmits the time information that the terminal itself has to the wireless terminal / wireless relay terminal that has transmitted the packet, This is a packet for broadcasting time information including other wireless terminals / wireless relay terminals.
  • Fig. 4 (A) shows the data communication packet.
  • the data communication packet 401 includes a transmission destination ID 405, a transmission source ID 406, a sequence number 407, a packet length 408, and a data communication payload area 409.
  • the transmission destination ID 405 stores information for identifying a transmission destination of a wireless packet, such as a MAC address of a terminal serving as a destination when the terminal itself transmits.
  • the transmission source ID 406 stores information for identifying the transmission source of the wireless packet such as the MAC address of the own terminal.
  • the sequence number indicates the order of the data communication packet 401 transmitted by the wireless terminal specified by the transmission source ID, and is used to correspond to the data confirmation response packet.
  • the packet length 408 is information indicating the length of the data communication packet 401.
  • the payload area for data communication stores application data to be transmitted, data for wireless multi-hop route control, and the like.
  • FIG. 4 (B) shows the data confirmation response packet.
  • the data confirmation response packet 402 includes a transmission destination ID 405, a transmission source ID 406, a sequence number 407, a packet length 408, and time synchronization information 410.
  • the sequence number 407 stores a sequence number included in the received data communication packet 401.
  • the time synchronization information 410 is common time information for synchronizing wireless networks, and stores time information immediately before the data confirmation response packet is transmitted.
  • the time synchronization information request packet 403 includes a transmission destination ID 405, a transmission source ID 406, a sequence number 407, a packet length 408, a time synchronization information request 411, and a time information requester ID 412.
  • the transmission destination ID 406 stores information specifying a terminal that makes a time synchronization information request. In particular, in the case of a wireless multi-hop network having a tree structure such as the wireless network 101, information specifying a parent terminal close to the gateway wireless terminal 101 is stored.
  • the time synchronization information request flag 411 stores information for identifying a time synchronization information request packet.
  • the time information requester ID 412 stores information for identifying the transmission source of the time synchronization information request packet, and may be the same information as the transmission source ID 406.
  • Fig. 4 (D) shows the time synchronization information distribution packet.
  • the time synchronization information distribution packet 404 includes a transmission destination ID 405, a transmission source ID 406, a sequence number 407, a packet length 408, time synchronization information 410, and a time information requester ID 412.
  • the time information requester ID stores a time information requester ID 412 corresponding to the received time synchronization information request packet 403.
  • FIG. 5 is a time synchronization packet flow diagram (unicast confirmation response) between wireless terminals according to the present embodiment.
  • the wireless terminal (H) 108 sends time information to the wireless relay terminal (F) 107 that is the parent terminal.
  • the request packet 403 is transmitted, and the wireless relay terminal (F) 107 broadcasts the time synchronization information distribution packet 404.
  • the time synchronization control unit 205 of the wireless terminal (H) 108 and the wireless terminal (K) 109 adjusts the time synchronization deviation according to the time synchronization information 410 of the time synchronization information packet 404, and the time synchronization ends.
  • the wireless terminal (K) 109 or the wireless terminal (H) 108 stores application data or the like in the data communication packet 401 and transmits it to the wireless relay terminal (F) (in FIG. 5, transmitted from the wireless terminal (K) 109.
  • the data confirmation response packet 402 corresponding to each data communication packet is transmitted to the wireless terminal (K) 109 by unicast (if transmitted from the wireless terminal (H) 108, it is transmitted to the wireless terminal (H) 108. )
  • the individual terminal that has received the data confirmation response packet 402 from the parent terminal adjusts the time synchronization deviation according to the time synchronization information 410 of the data confirmation response packet 402.
  • the time synchronization information is received. Use to adjust the time. This makes it possible for all the wireless terminals in the wireless network 101 to synchronize time using wireless communication.
  • FIG. 6 is a data transfer flowchart in wireless multi-hop communication according to the present embodiment.
  • data is collected via a gateway.
  • the wireless relay terminal determines that the packet is addressed to the GW, the wireless relay terminal that has received the packet transfers the data communication packet to a parent terminal that is higher than itself.
  • the wireless relay terminal (A) 102 receives the data communication packet 401 from the wireless relay terminal (C) 104, the wireless relay terminal (A) 102 determines in the wireless packet reception processing 601 that the final destination of the wireless network is the GW 101.
  • the gateway wireless terminal GW101 To the gateway wireless terminal GW101.
  • application data from a wireless terminal or a wireless relay terminal may be transmitted to the gateway wireless terminal GW by a plurality of times of unicast communication.
  • the number of synchronization adjustments is not the same for all terminals belonging to the wireless network 100, but is determined by the network topology. Specifically, the number of packet transmissions increases by becoming higher.
  • FIG. 7 is a diagram showing the time request transmission waiting time of each wireless terminal.
  • the time request transmission waiting time 701 includes a fixed part (T1) 702 and a traffic-dependent part (T2) 703.
  • the time request transmission waiting time 701 indicates a waiting time from when the previous time synchronization processing is performed to when the next time synchronization information request packet is transmitted.
  • the minimum value is the shortest interval for performing the synchronization error adjustment process, and is a fixed portion (T1) 702.
  • the maximum value is determined based on the synchronization error and clock performance in the wireless system, and is the longest period of time for performing the synchronization error adjustment processing to keep the synchronization accuracy in the wireless system constant.
  • the fixed part (T1) 702 is a value determined by the system.
  • the traffic dependence (T2) 703 is a value determined depending on neighboring communication traffic, and is determined by the traffic volume of the time synchronization information request packet 403 and the time synchronization information distribution packet 404 in the neighboring terminal.
  • the neighboring terminal refers to a terminal that belongs to the same parent terminal.
  • the time synchronization control unit extends the time request transmission waiting time to twice a fixed amount. Thereby, the possibility that a plurality of time synchronization information request packets 403 are simultaneously transmitted from child terminals belonging to the same parent terminal is reduced, and an increase in traffic volume due to the time information synchronization request packet 403 can be reduced. .
  • the extended time interval has been doubled as the traffic-dependent portion, it does not necessarily have to be doubled.
  • FIG. 8 shows an operation process of the transmission timing management of the time synchronization information request of each terminal.
  • Step 801 is processing in which the wireless terminal starts managing the transmission timing of the time synchronization information request packet 403.
  • Step 802 is processing for confirming whether or not there is a transmission reservation of the time synchronization information request packet 403. In this step, it is confirmed that the transmission timing management of the same time information request is started. If no transmission reservation has been made, the process proceeds to step 803, and if transmission reservation has already been made, the process proceeds to step 804.
  • Step 803 is a step for making a transmission reservation for the time synchronization information request packet 403. This step is the first setting, and the transmission after the fixed time (T1) 702 is set as the request transmission waiting time.
  • Step 804 is processing for determining whether or not the time managed in the own terminal exceeds the transmission reservation time of the time synchronization information request packet 403. If the reserved time has been exceeded, the process proceeds to step 805, and if not, the process proceeds to step 802.
  • Step 805 is a transmission process of the time synchronization information request packet 403.
  • a time synchronization information request packet 403 is transmitted to the parent terminal of the own terminal.
  • Step 806 is a process of confirming the set time for the request transmission waiting time.
  • the process proceeds to step 807, and if the fixed time (T1) 702 is longer than the transmission waiting time, the step Go to 802.
  • the request transmission time is Since there is no need to send a synchronization information request packet, it is extended.
  • this step is performed (YES in S806), it means that it has transmitted a time synchronization information request packet, so it is determined that there are no child terminals belonging to the same parent terminal around, It returns to the fixed time (T1) 702 which is the shortest frequency of the transmission interval of the synchronization information request packet.
  • T1 702 the fixed time
  • FIG. 9 shows an operation process when each terminal receives a radio packet.
  • Step 901 is processing for starting reception of a wireless packet.
  • Step 902 is processing for determining whether or not the received packet is the time synchronization information request packet 403. If it is the time synchronization information request packet 403, the process proceeds to step 906, and if it is any other packet, the process proceeds to step 903.
  • Step 903 is processing for determining whether or not the received packet is the time synchronization information distribution packet 404. If it is the time synchronization information distribution packet 404, the process proceeds to step 907, and if it is any other packet, the process proceeds to step 904.
  • Step 904 is processing for determining whether or not the received packet is the data confirmation response packet 402. If it is the data confirmation response packet 402, the process proceeds to step 910, and if it is any other packet, the process proceeds to step 905.
  • Step 905 is processing for determining whether or not the received packet is the data communication packet 401. If it is a data communication packet 402, the process proceeds to step 910, and if it is any other packet, the process proceeds to step 905.
  • Step 906 is a process for transmitting the time synchronization information distribution packet 404.
  • the time synchronization information distribution packet 404 is transmitted to the transmission source terminal of the time synchronization information request packet 403 received in step 901.
  • Step 907 performs reception processing of time synchronization information.
  • a time synchronization adjustment process using the time synchronization information 410 of the time synchronization information distribution packet 404 received by broadcast communication is performed.
  • Step 908 is a process for determining whether there is a process to be performed on the packet received in Step 901 other than the process related to the time synchronization process. Processing other than time synchronization processing includes application processing, path control processing, network address resolution processing, and the like. If there is a process to be performed, the process proceeds to step 909. If not, the radio packet reception process is terminated.
  • Step 909 is a packet reception process other than the process related to the time synchronization process for the packet received in step 901.
  • Step 910 is a process for receiving time synchronization information. This step is a time synchronization adjustment process using the time synchronization information 410 of the data confirmation response packet 402 received by unicast communication.
  • Step 911 is a process for performing an acknowledgment of the data communication packet received in Step 901.
  • a data confirmation response packet storing time information immediately before the transmission of the data confirmation response packet is transmitted to the transmission source terminal of the data communication packet.
  • FIG. 10 is a diagram for explaining in detail the processing in step 907 in FIG. 9, that is, the operation processing when receiving the time synchronization information 410 of the time synchronization information distribution packet 404 received by each terminal.
  • Step 1001 is a process of confirming the transmission source of the received time synchronization information distribution packet 404. If the transmission source is the parent terminal, the process proceeds to step 1002; otherwise, the process ends.
  • Step 1002 is a process of confirming whether or not the time information request ID 412 in the received time synchronization information distribution packet 404 is the own terminal. If the time information request ID is the local terminal, the process proceeds to step 1003. If the time information request ID is not the local terminal, the process proceeds to step 1005.
  • Step 1003 is a time synchronization adjustment process using the time synchronization information 410 of the received time synchronization information distribution packet 404.
  • Step 1004 is a process for setting the transmission time of the next time synchronization information request packet 403.
  • the next transmission time is a time obtained by adding the request transmission waiting time to the current free time.
  • Step 1005 is a process for confirming the length of the request transmission waiting time. If the request transmission waiting time is the prescribed maximum time, the process proceeds to step 1003, and if not, the process proceeds to step 1006.
  • Step 1006 is a process of extending the length of the request transmission waiting time.
  • the interval until the next request transmission waiting time is extended.
  • the method of extending the length of the traffic dependent portion (T2) 703 adds a fixed time (T1) 702 minutes to the current traffic dependent portion (T2) 703. Note that the method for extending the traffic dependence (T2) 703 is not limited to this as long as the value is increased.
  • FIG. 11 shows the processing in step 910 of FIG. 9, that is, the operation processing when receiving the time synchronization information 410 of the data confirmation response packet 402 received by each terminal.
  • Step 1101 is a process of confirming the transmission source of the received data confirmation response packet 402. If the transmission source is the parent terminal, the process proceeds to step 1003. Otherwise, the process ends.
  • the processing of steps 1003 and 1004 is the same as the processing of the same step number in FIG.
  • FIG. 12 shows a sequence for changing the reception timing of the time synchronization information distribution packet 404 and the transmission timing of the time synchronization information request packet 403.
  • the wireless terminal (H) 108 reserves the first time synchronization information request packet 403 transmission at time t11201, and reserves the second time at time t21202 when the fixed time (T1) 702 has elapsed.
  • the wireless terminal (K) 109 reserves the first time synchronization information request packet 403 transmission at time t31203, and reserves the second time at time t41204 when the fixed time (T1) 702 has passed.
  • the wireless terminal (K) 108 transmits the time synchronization information request packet 403 to the wireless relay terminal (F) 107 at time t1, and receives the packet in accordance with the operation processing of the transmission timing management of the time synchronization information request of each terminal in FIG.
  • the wireless relay terminal (F) 107 broadcast-transmits the time synchronization information distribution packet 404, and the wireless terminal (K) 108 and the wireless terminal (F) 109 receive them.
  • the wireless terminal (K) 108 and the wireless terminal (F) 109 set the transmission time of the next time synchronization information request packet in accordance with the operation processing at the time of reception of the wireless packet of each terminal in FIG. Since the wireless terminal (K) 108 requested the same time information itself, the transmission time of the next time synchronization information request packet 403 is not changed from the time t21202 when the fixed time (T1) 702 has passed.
  • the transmission waiting time (T) is reserved at time t51205 to which a fixed time (T1) 702 is further added as a traffic-dependent portion, and time t31203 And the reservation at time t41204 is canceled.
  • T1 a fixed time
  • FIG. 13 shows a sequence for receiving the data confirmation response packet 402 and the time synchronization information distribution packet 404 and changing the transmission timing of the time synchronization information request packet 403.
  • FIG. 12 shows a transmission timing change sequence of the time synchronization information request packet 403 when a data communication packet from the wireless terminal (H) 108 to the wireless relay terminal (F) 107 is generated in addition to the communication traffic of FIG.
  • the wireless terminal (H) 108 transmits a data communication packet to the wireless relay terminal (F) 107 at time t61301, and the wireless relay terminal (F) 107 transmits a data confirmation response packet 402 to the wireless terminal (H) 108.
  • the wireless terminal (H) 108 that has received the data confirmation response packet 402 cancels the transmission reservation at time t2 in accordance with the operation processing when receiving the time synchronization information 410 of the data confirmation response packet 402 in FIG.
  • the request packet 403 is reserved at time t71302 when the fixed time (T1) 702 has elapsed.
  • T1 702 has elapsed.
  • the transmission interval of the time synchronization information request packet is adjusted according to the communication traffic around the terminal itself, in particular, the traffic volume of the time synchronization information distribution packet 404, and data communication occurs periodically.
  • the transmission interval of the time synchronization information request packet transmitted by the wireless terminal it is possible to reduce the time synchronization information request packet and keep the time synchronization accuracy in the wireless network at a certain level or more.
  • a wireless network is constructed using a wireless communication method in which only the transmission source ID 406 is confirmed when a data confirmation response packet is received.
  • FIG. 1 Wireless communication system according to the present embodiment
  • terminal hardware configuration FIGGS. 2 and 3
  • wireless packet configuration FIGG. 4
  • time request transmission waiting time configuration FIGG. 7
  • Each terminal's time synchronization information request transmission timing management processing FIG. 8
  • each terminal's wireless packet reception procedure FIG. 9
  • each terminal's time synchronization information reception procedure 1 FIG. 10
  • Processing procedure 2 FIG. 11 when receiving time synchronization information of the terminal is the same as in the first embodiment.
  • FIG. 14 is a time synchronization packet flow diagram between wireless terminals according to the present embodiment.
  • the wireless terminal (H) 108 sends time information to the wireless relay terminal (F) 107 that is the parent terminal.
  • the request packet 403 is transmitted, and the wireless relay terminal (F) 107 broadcasts the time synchronization information distribution packet 404.
  • the wireless terminal (H) 108 and the wireless terminal (K) 109 adjust the time synchronization deviation according to the time synchronization information 410 of the time synchronization information packet 404.
  • the wireless terminal (K) 109 and the wireless terminal (H) 108 store application data and the like in the data communication packet 401 and transmit them to the wireless relay terminal (F).
  • the data confirmation response packet 402 corresponding to each data communication packet is transmitted to the wireless terminal (K) 109 and the wireless terminal (H) 108 by unicast. Even in the case of unicast communication or broadcast communication, there is a high possibility that the radio wave will arrive in the same way.
  • the transmission source ID 406 is the parent terminal of the own terminal, each terminal receives a radio packet.
  • the time synchronization deviation is adjusted according to the processing procedure (FIG. 9) of FIG. 9 and the processing procedure 2 (FIG. 11) when receiving the time synchronization information of each terminal. This makes it possible for all the wireless terminals in the wireless network 101 to synchronize time using wireless communication.
  • time synchronization adjustment processing by a data confirmation response packet can be performed. It is possible to reduce the traffic of the unnecessary time synchronization information request packet 403 while keeping the time synchronization error constant.
  • the communication traffic necessary for time synchronization in the wireless network is reduced, so that the communication traffic of the entire network can be suppressed, and a sensor network that automatically generates a certain amount of data communication traffic or power automatic In the meter-reading network, the number of wireless terminals existing under one gateway can be increased, which is effective in reducing the cost of the entire system.
  • the time synchronization information distribution packet can be actively requested instead of being periodically and passively received. Since the time synchronization error in the wireless network can be kept constant, it is not necessary to require high clock accuracy, which is effective for reducing the cost of the wireless terminal.
  • DESCRIPTION OF SYMBOLS 100 ... Wireless network, 101 ... Gateway wireless terminal (GW), 102 ... Wireless relay terminal (A), 103 ... Wireless relay terminal (B), 104 ... Wireless relay terminal (C), 105 ... Wireless terminal (D), 106 ... wireless relay terminal (E), 107 ... wireless relay terminal (F), 108 ... wireless terminal (H), 109 ... wireless terminal (I), 110 ... wireless terminal (J), 111 ... wireless terminal (K), 112 ... Wireless terminal (G), 202 ... Microcomputer, 203 ... ROM, 204 ... Central control unit, 205 ... Time synchronization control unit, 206 ... Path management unit, 207 ... Wireless communication processing unit, 208 ... RAM, 209 ...
  • Clock generation circuit 210 Power supply circuit, 211 ... RF peripheral circuit, 301 ... Gateway wireless terminal, 312 ... External network connection circuit, 401 ... Data communication packet, 402 ... Data confirmation response packet, 403 ... Time synchronization information request packet, 404 ... Time synchronization Information distribution packet, 405 ... transmission destination ID, 406 ... transmission source ID, 407 ... sequence 408 ... packet length, 409 ... payload area for data communication, 409 ... time synchronization information, 410 ... time synchronization information request flag, 410 ... time synchronization information requester ID, 601 ... radio packet reception processing, 701 ... time request Transmission waiting time (T), 702 ... fixed part (T1), 702 ...
  • T2 traffic dependent part
  • 1201 ... time (t1) 1202 ... time (t2), 1204 ... time (t3), 1204 ... time (t4)
  • 1205 ... time (t5) 1205 ... time (t5), 1301 ... time (t6), 1302 ... time (t7).

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

La présente invention se rapporte à un procédé adapté pour exécuter une synchronisation temporelle cohérente et de grande précision entre des terminaux dans un réseau sans fil. Le procédé adapté pour exécuter une synchronisation temporelle entre des terminaux dans un réseau sans fil, selon l'invention consiste : à allonger ou à raccourcir progressivement l'intervalle de transmission de paquets de requête de synchronisation temporelle en se basant sur le volume d'un trafic de données adjacent antérieur ; à exécuter une synchronisation temporelle sans générer de communications supplémentaires en vue de les utiliser lors de l'exécution de la synchronisation temporelle à un endroit où un trafic fixe de transmission de données est généré ; et à générer volontairement un trafic de transmission en vue de l'utiliser lors de l'exécution de la synchronisation temporelle à un endroit où un trafic fixe de transmission de données n'est pas généré.
PCT/JP2012/069536 2012-08-01 2012-08-01 Procédé pour l'exécution d'une synchronisation temporelle dans un système de réseau sans fil WO2014020714A1 (fr)

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JP2014527884A JP5868506B2 (ja) 2012-08-01 2012-08-01 無線ネットワークシステムにおける時刻同期方法

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016158866A1 (fr) * 2015-03-30 2016-10-06 三菱電機株式会社 Dispositif de communication, dispositif d'authentification et système de réseau
JP2017009366A (ja) * 2015-06-19 2017-01-12 カシオ計算機株式会社 無線通信装置、電子時計、無線通信方法、及びプログラム
CN114503699A (zh) * 2019-10-11 2022-05-13 株式会社Ntt都科摩 终端

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