JP2015115858A - Radio communication system and communication control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system and a communication control method which can surely transmit traffic information in the radio communication system.SOLUTION: A radio communication system comprises a master station and one or a plurality of slave stations which are radio stations for transmitting traffic information by radio. The master station can transmit communication packets to the slave stations at predetermined intervals. In response to reception of the communication packets, the slave station transmits the communication packets or other communication packets. The communication packets includes: control packets which can store communication quality information of the radio stations and can pass each of the radio stations; and serial packets which is to be exchanged between the corresponding slave station and the master station.

Description

  The present invention relates to a wireless communication system and a communication control method, and more particularly to a wireless communication system and a communication control method for wirelessly transmitting traffic information.

  Developed traffic control system to transmit traffic information between signal control device and vehicle detector or between signal control device and central device at control center to control the color of signal lights at multiple intersections Has been.

  Conventionally, communication between traffic equipment such as a signal control device and a vehicle detector has been mainly wired communication using a communication line buried underground or installed on a utility pole. On the other hand, in recent years, a wireless communication system that communicates between traffic facilities using a wireless LAN (Local Area Network) has been developed for the purpose of avoiding road restrictions for wiring work and reducing construction costs. Has been.

  For example, Japanese Unexamined Patent Application Publication No. 2008-205765 (Patent Document 1) discloses the following wireless communication system. In other words, in the traffic control system, communication data relating to device status and control is exchanged between a traffic signal controller or an optical beacon installed on the road and a central device installed in the traffic control center. When the first wireless communication device transmits the communication data to the second wireless communication device, the first wireless communication device monitors the noise characteristics and the like of the wireless communication paths A to C to determine the communication speed at which communication is possible. Get average and minimum values. The attribute of the communication data is acquired, and the priority according to the attribute is acquired from the priority table. Then, an appropriate wireless communication path is selected and transmitted based on the acquired average value of the communication speed and the priority.

JP 2008-205765 A

S6 interface standard, New Traffic Management System Association, March 18, 1999, Edition 2, P5-9

  For example, when a wireless communication system is applied to the above traffic control system, the possibility of communication failure due to radio wave interference or the like may be higher than that of wired communication. A technology that can reliably transmit traffic information between traffic facilities without being greatly affected by the occurrence of such communication failures is desired.

  This invention was made in order to solve the above-mentioned subject, and the objective is to provide the radio | wireless communications system and communication control method which can transmit traffic information more reliably in a radio | wireless communications system. .

  (1) In order to solve the above-described problem, a wireless communication system according to an aspect of the present invention is a wireless communication system including a master station that is a wireless station for wirelessly transmitting traffic information and one or more slave stations. The master station can transmit a communication packet to the slave station at a predetermined interval, and the slave station transmits the communication packet or another communication packet in response to receiving the communication packet. The communication packet can store the communication quality information of the wireless station and can be transmitted and received between the corresponding slave station and the master station. Serial packets to be transmitted.

  (16) In order to solve the above-described problem, a communication control method according to an aspect of the present invention is provided in a wireless communication system including a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations. A communication control method, wherein the master station transmits a communication packet to the slave station at a predetermined interval, and the slave station receives the communication packet or other communication in response to receiving the communication packet. Transmitting the packet, the communication packet can store the communication quality information of the wireless station and can pass through each of the wireless stations, the corresponding slave station and the above And serial packets transmitted and received between the master stations.

  (17) In order to solve the above-described problem, a wireless communication system according to another aspect of the present invention is a wireless communication system including a master station and a slave station that are wireless stations for wirelessly transmitting traffic information. The traffic information includes contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the radio station. A plurality of the contact information is generated in time series, and the contact processing unit for adding time information to each of the generated contact information, the contact information to which the time information is added by the contact processing unit, and the serial information are separately provided. The packet generator included in the packet and whether or not another wireless station is transmitting a radio signal, and if it is determined that the other wireless station is not transmitting a radio signal, The main station acquires the contact information from the plurality of received packets, and based on the time information added to the acquired contact information, the main station The contact information is rearranged in chronological order.

  (19) In order to solve the above-described problem, a communication control method according to another aspect of the present invention is a communication control method in a wireless communication system including a master station and a slave station that are wireless stations for wirelessly transmitting traffic information. The traffic information includes contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the radio station, The slave station generates a plurality of the contact information in time series, and adds the time information to each of the generated contact information, and the slave station separately generates the contact information and the serial information to which the time information is added. And transmitting the packet to the master station. In the step of transmitting the packet to the master station, the slave station transmits a radio signal from another radio station. The packet is transmitted when it is determined that the other radio station is not transmitting a radio signal, and the communication control method further includes a plurality of received by the main station. Acquiring the contact information from the packet, and rearranging the contact information in chronological order based on the time information added to the acquired contact information.

  The present invention can be realized not only as a wireless communication system including such a characteristic processing unit, but also as a wireless station including such a characteristic processing unit, or causing a computer to execute the steps of such characteristic processing. Or can be realized as a program. Also, it can be realized as a semiconductor integrated circuit that realizes part or all of the radio station.

  According to the present invention, traffic information can be more reliably transmitted in a wireless communication system.

FIG. 1 is a diagram showing a configuration of a wireless communication system according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating an application example of the radio communication system according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an example of contact information processed by the wireless station according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating an example of a communication packet transmitted / received by a wireless station configuring the wireless communication system according to the first embodiment of the present invention. FIG. 5 is a diagram illustrating an example of communication packet transmission in the wireless communication system according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an example of communication packet transmission in the wireless communication system according to the first embodiment of the present invention. FIG. 7 is a diagram showing a configuration of a wireless communication apparatus in the wireless communication system according to the first embodiment of the present invention. FIG. 8 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention. FIG. 9 is a diagram showing an example of an entry table stored in the storage unit according to the first embodiment of the present invention. FIG. 10 is a diagram showing a configuration of the packet management unit in the packet processing unit according to the first embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 12 is a diagram illustrating an example of a communication schedule for three consecutive periods created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 13 is a diagram illustrating an example of a communication schedule changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 14 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 15 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 16 is a diagram illustrating an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 17 is a diagram showing an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 18 is a diagram illustrating an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 19 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 20 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 21 is a diagram illustrating a configuration of the control packet processing unit in the packet processing unit according to the first embodiment of the present invention. FIG. 22 is a diagram illustrating an example of a CP reception state transition route set in the control packet processing unit according to the first embodiment of the present invention. FIG. 23 is a diagram showing an example of a CP reception state transition table used in the control packet processing unit according to the first embodiment of the present invention. FIG. 24 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention. FIG. 25 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention. FIG. 26 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention. FIG. 27 is a flowchart defining an operation procedure when the master station, the relay station, and the slave station transmit and receive communication packets in the wireless communication system according to the first embodiment of the present invention. FIG. 28 is a flowchart defining an operation procedure when the relay station and the slave station transmit and receive control packets in the wireless communication system according to the first embodiment of the present invention. FIG. 29 is a diagram illustrating an application example of the wireless communication system according to the second embodiment of the present invention. FIG. 30 is a diagram illustrating an example of a communication packet transmitted and received by a wireless station configuring the wireless communication system according to the second embodiment of the present invention. FIG. 31 is a diagram illustrating a configuration of a wireless communication device in a wireless communication system according to the second embodiment of the present invention. FIG. 32 is a flowchart defining an operation procedure when a slave station transmits a communication packet in the wireless communication system according to the second embodiment of the present invention. FIG. 33 is a flowchart defining an operation procedure when a relay station relays a communication packet in the wireless communication system according to the second embodiment of the present invention. FIG. 34 is a flowchart defining an operation procedure when setting the priority of communication packets received by the main station in the wireless communication system according to the second embodiment of the present invention. FIG. 35 is a flowchart defining an operation procedure when generating a contact signal from contact information received by the main station in the wireless communication system according to the second embodiment of the present invention. FIG. 36 is a diagram illustrating an example of a sequence when contact information and serial information are transmitted to the main station according to priority in the wireless communication system according to the second embodiment of the present invention.

  First, the contents of the embodiment of the present invention will be listed and described.

  (1) A radio communication system according to an embodiment of the present invention is a radio communication system including a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations, The communication packet can be transmitted to the slave station at a predetermined interval, and the slave station transmits the communication packet or another communication packet in response to receiving the communication packet, and the communication packet Includes a control packet capable of storing communication quality information of the wireless station and capable of passing through each wireless station, and a serial packet transmitted / received between the corresponding slave station and the parent station. It is.

  As described above, the configuration in which the master station transmits the communication packet at a predetermined interval can increase the transmission opportunity of the communication packet, thereby increasing the substantial amount of traffic information to be wirelessly transmitted. Thereby, since it is possible to increase redundancy in transmission of traffic information, it is possible to reduce the possibility of failure in transmission of traffic information between traffic facilities.

  In addition, the configuration in which the slave station transmits a communication packet or another communication packet in response to the reception of the communication packet can reduce the time during which wireless transmission is not performed, so that the time utilization efficiency is improved, And punctuality can be ensured. Thereby, the request | requirement of the delay time of traffic information can be satisfy | filled.

  In addition, by using a control packet passing through a cyclic communication path passing through each wireless station and a serial packet passing through a peer-to-peer communication path between the parent station and the corresponding slave station, traffic information in wireless transmission It is possible to diversify communication paths and select an appropriate communication path according to the type of information to be transmitted. Therefore, traffic information can be more reliably transmitted between traffic facilities.

  (2) Preferably, the control packet is retransmitted when it is determined that it has not been possible to return to the predetermined radio station via the slave station or the master station, and a new packet to be included in the serial packet. Until the information is acquired, the serial packet having the same content as the previously transmitted serial packet is repeatedly transmitted.

  As described above, the configuration in which the control packet is retransmitted until a predetermined wireless station receives the control packet via the parent station or the slave station increases the possibility that the wireless station targeted for the control packet can receive the control packet. be able to.

  In addition, a serial packet with the same content as the previously transmitted serial packet is repeatedly transmitted until new information to be included in the serial packet is acquired, so that the destination wireless station of the serial packet can receive the serial packet. Can increase the sex. That is, redundancy in transmission of control packets and serial packets can be increased.

  (3) Preferably, the traffic information is contact information indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the master station or the slave station. The control packet can further store the contact information, the serial packet can store the serial information, and at least one of the master station and the slave station is The communication quality information and the contact information can be stored in the control packet.

  With this configuration, communication quality information and contact information can be stored in the control packet at any wireless station that is the target of the control packet, and the stored information is transmitted to all the wireless stations that are the target of the control packet. Therefore, the collection and delivery efficiency of communication quality information and contact information can be increased.

  As a result, for example, communication quality information in all the wireless stations that are to be routed through the control packet can be collected, so that the communication state in the wireless communication system can be easily grasped based on the collected communication quality information.

  In addition, since the contact information stored in the control packet in a certain radio station can be easily transmitted to another radio station, for example, the vehicle sensing result measured in the terminal connected to the certain radio station The terminal can be used easily. That is, it is possible to easily relax restrictions on a terminal that uses a vehicle sensing result measured at a certain terminal.

  In addition, since serial information can be transmitted through a peer-to-peer communication path between a master station and a corresponding slave station, for example, centralized management of serial information by a terminal connected to the master station can be efficiently performed. it can.

  (4) Preferably, when the information included in the received control packet is the same as the information included in the previously received control packet, the slave station has received the previous control packet and transmitted to another station. The control station retransmits the control packet to the other station, and the slave station includes the control packet received in which the information addressed to the local station is included in the received control packet, and the information included in the received control packet has been previously received. If it is different from the information contained in the information, the information addressed to the local station received this time is transmitted to the terminal connected to the local station, and the slave station includes the information addressed to the local station in the received control packet. If the information contained in the received control packet is the same as the information contained in the previously received control packet, the information addressed to the own station received this time is discarded.

  With such a configuration, since the information transmitted to the other station at the first time can be transmitted to the other station as it is after the second time when it is retransmitted, the same information is stored in the wireless station through which the control packet is routed. Control packets can be received regardless of the number of retransmissions.

  That is, for example, when the control packet periodically circulates through each radio station, the information stored in the control packet can be determined for each transmission cycle. The content of the information to be circulated can be unified.

  In addition, it is possible to prevent the slave station from repeatedly transmitting the same information to a terminal connected to the slave station, so that the processing load can be reduced.

  In addition, since it is possible to avoid the terminal receiving the same information repeatedly, even if a control packet having the same content is retransmitted, useless reception processing at the terminal can be avoided.

  (5) Preferably, when the received serial packet does not include information addressed to the local station, the slave station transmits the serial packet received this time to another station, and the slave station receives the received serial packet. If the serial packet contains information addressed to the local station and the information included in the received serial packet is different from the information included in the serial packet received last time, the information addressed to the local station The slave station transmits information to the terminal connected to the station, and the slave station includes the information addressed to the local station in the received serial packet, and the information included in the received serial packet is included in the previously received serial packet. If the information is the same as the included information, the information addressed to the local station received this time is discarded.

  With such a configuration, serial packets can be appropriately transferred along a peer-to-peer communication path.

  In addition, it is possible to prevent the slave station from repeatedly transmitting the same information to a terminal connected to the slave station, so that the processing load can be reduced.

  Further, since it is possible to avoid the terminal receiving the same information repeatedly, even if a serial packet having the same content is retransmitted, it is possible to avoid useless reception processing at the terminal.

  (6) Preferably, the master station or the slave station sends the control packet a predetermined number of times to the subordinate station that is the slave station connected to the slave station on the downstream side from the master station to the slave station. If the control packet or the response of the control packet does not return from the lower station to the own station even after transmission, the lower station is excluded from the transmission destination of the control packet, and the lower station The control packet is transmitted to the upper station, which is the parent station or the child station, connected to the upstream side to the parent station, or to another lower station.

  With such a configuration, even when a communication abnormality occurs in the lower station, the control packet can be circulated while avoiding the lower station where the communication abnormality has occurred. As long as it can be stored in the control packet and transmitted.

  (7) More preferably, when the lower station does not receive the control packet for a predetermined time from the upper station, the lower station transmits a recovery notification for notifying that the own station has recovered to the upper station.

  As described above, the lower-level station that is excluded from the control packet transmission target transmits the recovery notification to the higher-level station, so that the lower-level station secures the transmission opportunity of the packet including the recovery notification, for example, without receiving the communication packet. The upper station can recognize the recovery of the own station.

  (8) More preferably, when the upper station receives the recovery notification from the lower station and excludes the lower station from the transmission destination of the control packet, the upper station transmits the lower packet to the transmission destination of the control packet. Add a station.

  With such a configuration, when a lower station where a communication error has occurred is restored, the lower station can be re-incorporated into the control packet routed object. Information from a slave station connected to the downstream side of the station can be stored in a control packet and transmitted.

  (9) More preferably, the control packet is transmitted periodically, and the serial packet can be transmitted in a period in which the control packet is not transmitted in the transmission period of the control packet, and the control packet is transmitted in each transmission period. The packet is transmitted before the serial packet, and the transmission of the serial packet is started when a predetermined condition is satisfied.

  In this way, contact information is stored at least once in a transmission cycle for each wireless station in a wireless communication system, for example, by periodically transmitting a control packet capable of storing contact information acquired periodically. Can give an opportunity. Further, the timing for ending the transmission of the serial packet can be easily set according to the timing for ending the transmission cycle of the control packet.

  (10) More preferably, the control packet has a maximum allowable time for returning to the predetermined radio station via the slave station or the master station, and the length of the transmission cycle is It is 1/2 or less of the maximum allowable time.

  In this way, with the configuration in which the control packet is transmitted at least twice within the maximum allowable time, one wireless station acquires information from a terminal connected to the wireless station and then another wireless station acquires the information. Since it is possible to keep the time until the time is within the maximum allowable time, for example, it is possible to easily satisfy the request for the delay time of the contact information.

  (11) More preferably, the predetermined condition is that the number of times the control packet is retransmitted reaches a predetermined value, or the control packet returns to the predetermined radio station via the slave station or the master station. That is.

  In this way, transmission of a serial packet can be started under an appropriate condition such as when the control packet returns after traversing the target wireless station or when redundancy in the transmission of the control packet can be ensured to the minimum. it can.

  (12) More preferably, when the serial packet is not transmitted in the wireless communication system, the predetermined value is set to a maximum number of times that can be retransmitted in the transmission cycle.

  With such a configuration, it is possible to further increase redundancy in transmission of control packets.

  (13) Preferably, after the control packet is transmitted from the master station, the control packet is returned to the master station via all the slave stations, and the number of the radio stations passing therethrough is minimized. Sent to.

  With such a configuration, the communication quality information can be stored in the control packet in each wireless station in the wireless communication system, and the stored communication quality information can be efficiently transmitted to the master station. Can be increased.

  In addition, since the time required for circulating control packets can be shortened, it is possible to suppress an increase in the transmission interval of control packets.

  (14) Preferably, the control packet is retransmitted when it is determined that the control packet cannot be returned to the predetermined radio station via one or more radio stations, and the retransmission interval of the control packet is: The length is set according to the number of the radio stations to which the control packet is to be transmitted in the radio communication system.

  With such a configuration, it is possible to appropriately set the timing for starting the retransmission processing of the control packet, so that it is possible to avoid a situation where the control packet is continuously waited for the return of the control packet.

  In addition, since it is possible to set a retransmission interval according to the time required for the control packet to circulate through the wireless stations to be routed, a situation in which a plurality of control packets circulate each wireless station in the wireless communication system is avoided. Can do. Thereby, it is possible to avoid a communication failure due to interference between radio waves including the control packet.

  (15) Preferably, the serial packets are transmitted at intervals, and the transmission interval of the serial packets is set to a length according to the transmission rate of the traffic information.

  With such a configuration, it is possible to set a transmission interval according to the time required for transmission / reception of a serial packet between a master station and a corresponding slave station, so that a plurality of serial packets can be transmitted between radio stations in a radio communication system. It is possible to avoid the situation where data is transmitted and received. Thereby, it is possible to avoid a communication failure due to interference between radio waves including serial packets.

  (16) A communication control method according to an embodiment of the present invention is a communication control method in a wireless communication system including a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations, The master station transmitting a communication packet to the slave station at a predetermined interval; and the slave station transmitting the communication packet or another communication packet in response to receiving the communication packet. The communication packet includes the control packet that can store the communication quality information of the radio station and can pass through the radio station, and is transmitted / received between the corresponding slave station and the master station. And serial packets.

  As described above, the configuration in which the master station transmits the communication packet at a predetermined interval can increase the transmission opportunity of the communication packet, thereby increasing the substantial amount of traffic information to be wirelessly transmitted. Thereby, since it is possible to increase redundancy in transmission of traffic information, it is possible to reduce the possibility of failure in transmission of traffic information between traffic facilities.

  In addition, the configuration in which the slave station transmits a communication packet or another communication packet in response to the reception of the communication packet can reduce the time during which wireless transmission is not performed, so that the time utilization efficiency is improved, And punctuality can be ensured. Thereby, the request | requirement of the delay time of traffic information can be satisfy | filled.

  In addition, by using a control packet passing through a cyclic communication path passing through each wireless station and a serial packet passing through a peer-to-peer communication path between the parent station and the corresponding slave station, traffic information in wireless transmission It is possible to diversify communication paths and select an appropriate communication path according to the type of information to be transmitted. Therefore, traffic information can be more reliably transmitted between traffic facilities.

  (17) A wireless communication system according to an embodiment of the present invention is a wireless communication system including a master station and a slave station that are wireless stations for wirelessly transmitting traffic information, and the traffic information includes vehicle detection information. Contact information based on a contact signal indicating presence and absence, and serial information that is different from the contact information and is information from a terminal connected to the wireless station, and the slave station includes a plurality of the contact information in time series. A contact processing unit that generates and adds time information to each of the generated contact information, a packet generation unit that includes the contact information to which the time information is added by the contact processing unit, and the serial information in a separate packet; Packet transmission that determines whether other radio stations are transmitting radio signals, and transmits the above packet when it is determined that other radio stations are not transmitting radio signals The main station obtains the contact information from the received plurality of packets, and arranges the contact information in chronological order based on the time information added to the obtained contact information. Change.

  Thus, the configuration in which a packet is transmitted when a slave station determines that a radio signal is not transmitted by another radio station can reduce the probability of occurrence of a communication failure due to interference or the like.

  In addition, for example, even when a plurality of packets including contact information are transmitted according to the CSMA / CA (Carrier Sense Multiple Access Avidance) method in which the order of packet transmission is likely to change, the main station is based on the time information. Thus, the pieces of contact information included in the plurality of packets can be correctly sorted in the order of generation. Therefore, traffic information can be more reliably transmitted between traffic facilities.

  (18) Preferably, the wireless communication system further includes a relay station that relays the packet between the master station and the slave station, and the relay station receives each packet received based on the time information. Among them, the packet including the contact information generated within a predetermined time is preferentially relayed.

  In this way, the configuration that relays a packet including contact information that is new to a certain degree of priority can shorten the delay time of the contact information and increase the possibility of satisfying the delay time requirement in the traffic control system. it can.

  (19) A communication control method according to an embodiment of the present invention is a communication control method in a wireless communication system including a master station and a slave station that are wireless stations for wirelessly transmitting traffic information, and the traffic information includes: Contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is different from the contact information and is information from a terminal connected to the wireless station. Generating a plurality of time series, adding time information to each of the generated contact information, and the slave station including the contact information and the serial information to which the time information is added in separate packets. In the step of transmitting the packet to the master station, the slave station determines whether or not another radio station is transmitting a radio signal. When it is determined that the wireless station is not transmitting a wireless signal, the packet is transmitted, and the communication control method further includes that the main station acquires the contact information from the plurality of received packets, Based on the time information added to the acquired contact information, the step of rearranging the contact information in chronological order is included.

  Thus, the configuration in which a packet is transmitted when a slave station determines that a radio signal is not transmitted by another radio station can reduce the probability of occurrence of a communication failure due to interference or the like.

  In addition, for example, even when a plurality of packets including contact information are transmitted according to the CSMA / CA method in which the order of packet transmission is likely to be changed, the main station transmits each packet included in the plurality of packets based on the time information. The contact information can be correctly sorted in the order of generation. Therefore, traffic information can be more reliably transmitted between traffic facilities.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. Moreover, you may combine arbitrarily at least one part of embodiment described below.

<First Embodiment>
FIG. 1 is a diagram showing a configuration of a wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 1, a wireless communication system 301 includes a master station (parent station) 101, one or more slave stations (slave stations) 202, a wireless LAN network 201, and a plurality of terminals A to G. The wireless LAN network 201 includes one or more relay stations (slave stations) 151. The wireless LAN network 201 may include one or more slave stations 202. Further, the wireless communication system 301 may be configured not to include the relay station 151.

  The master station 101, the relay station 151, and the slave station 202 can communicate with each other by transmitting and receiving radio signals in the 2.4 GHz band that is an ISM band (Industry Science Medical band), for example, in accordance with the IEEE 802.11 standard.

  Hereinafter, each of the master station 101, the relay station 151, and the slave station 202 may be referred to as a radio station.

  The master station 101 manages each relay station 151 and each slave station 202 in the wireless communication system 301. More specifically, for example, the master station 101 transmits a communication packet to the relay station 151 and the slave station 202, and receives a response packet for the communication packet from the relay station 151 and the slave station 202. The master station 101 can refer to communication quality information such as RSSI (Received Signal Strength Indication) and noise level in each relay station 151 and each slave station 202, setting information, and the like. Further, the master station 101 can make settings related to the operation contents of each relay station 151 and each slave station 202.

  For example, the master station 101 is connected to the terminals A and B by wire, includes the information received from the terminals A and B in a wireless signal, transmits the information to the relay station 151 or the slave station 202, and receives the radio signal received from the relay station 151 or the slave station 202. Information included in the signal is transmitted to terminals A and B. The number of terminals connected to the main station 101 by wire may be one or three or more. In addition, the communication speed, that is, the transmission rate in wired communication is, for example, 9600 kbps.

  For example, the slave station 202 is connected to a terminal in a wired manner, includes information received from the terminal in a wireless signal, transmits the information to the master station 101 or the relay station 151, and is included in the wireless signal received from the master station 101 or the relay station 151. Send information to the terminal. In FIG. 1, a state in which terminal D, terminal E, and terminals F and G are connected to three slave stations 202 is shown as an example.

  In the wireless communication system 301 used for the traffic control system, it is difficult to use a large high gain antenna due to the limitation of the surrounding landscape, and the transmission distance between a pair of wireless stations is about 300 meters, Often required. That is, for example, the relay station 151 is disposed when the distance between the master station 101 and the slave station 202 is long, relays traffic information exchanged between the master station 101 and the slave station 202, and also transmits the traffic information to a plurality of wireless stations. It is possible to branch to a station. Further, for example, the master station 101, the relay station 151, and the slave station 202 are installed in a place where radio transmission within a line of sight is possible.

  The relay station 151 can also acquire traffic information transmitted from the master station 101, the slave station 202, and other relay stations 151, and perform various processes. In addition, the relay station 151 is connected to a terminal by wire, for example, includes information received from the terminal in a wireless signal and transmits the information to the master station 101, the other relay station 151, or the slave station 202. Information included in the radio signal received from the station 151 or the slave station 202 is transmitted to the terminal. In FIG. 1, a state in which terminal C is connected to one relay station 151 is shown as an example. The relay station 151 and the terminal connected to the relay station 151 can perform the same communication operation as the slave station 202 and the terminal connected to the slave station 202. Note that the relay station 151 may not be connected to a terminal by wire.

  In the wireless communication system 301, for example, a plurality of interface types are prepared according to the type of information transmitted between terminals. Specifically, for example, for contact information transmitted between terminals, interfaces defined by P1 and P2 are prepared. Further, for example, for serial information transmitted between terminals, interfaces defined in S4 to S6 and S9 to S11 are prepared. Details of the contact information and serial information will be described later.

  FIG. 2 is a diagram illustrating an application example of the radio communication system according to the first embodiment of the present invention.

  With reference to FIG. 2, a wireless communication system 301 is used in, for example, a traffic control system 401. The traffic control system 401 includes a master station 101, a relay station 151, three slave stations 202, a central side communication device (TTR) 160, two traffic signals 161, an optical beacon 162, an image sensor 163, 2 Two ultrasonic sensors 164. The central communication device 160, traffic signal 161, optical beacon 162, image sensor 163, and ultrasonic sensor 164 correspond to the terminal shown in FIG.

  The central device 251 installed in the traffic control center performs overall control of the color of each signal lamp installed at, for example, a plurality of intersections or roads.

  More specifically, the central device 251 transmits signal control command information indicating the signal lamp color switching timing to the central communication device 160.

  The central communication device 160 transmits the signal control command information received from the central device 251 to the traffic signal device 161 via the master station 101, the relay station 151, and the slave station 202.

  The traffic signal 161 includes a signal lamp and a signal controller. The signal lamp is installed at an intersection or a road, and switches a lamp color such as red, blue, or yellow to display a signal to a vehicle driver or a pedestrian. The signal controller performs control to switch the lamp color of the signal lamp unit based on the signal control command information received from the central device 251.

  In addition, the signal controller transmits signal control execution information indicating its own operation history such as signal lamp switching control to the central communication device 160 via the slave station 202, the relay station 151, and the master station 101.

  The central communication device 160 transmits the signal control execution information received from the signal controller to the central device 251.

  In addition, the central apparatus 251 creates VICS (Vehicle Information and Communication System) (registered trademark) information and transmits it to the central communication apparatus 160.

  The central communication device 160 transmits the VICS information received from the central device 251 to the optical beacon 162 via the main station 101 and the relay station 151.

  The optical beacon 162 can perform two-way communication using a near-infrared ray with a communication device mounted on the vehicle, for example. The optical beacon 162 provides, for example, the VICS information received from the central communication device 160 to the vehicle, and the vehicle information such as the travel time of the travel route received from the communication device mounted on the vehicle, and the relay station 151 and the main station. 101 to the central communication device 160.

  The image sensor 163 images the vehicle and transmits image information of the vehicle to the central communication device 160 via the slave station 202, the relay station 151, and the master station 101. Further, the image sensor 163 transmits, for example, the speed of the vehicle, the number of passing vehicles, or the congestion length to the central communication device 160 via the slave station 202, the relay station 151, and the master station 101.

  FIG. 3 is a diagram illustrating an example of contact information processed by the wireless station according to the first embodiment of the present invention.

  Referring to FIG. 3, the ultrasonic sensor 164 is an ultrasonic vehicle sensor installed, for example, above a road. The ultrasonic sensor 164 generates a contact signal PS1 that is an analog pulse signal that represents the presence or absence of vehicle detection in binary. The contact signal PS1 becomes high level when the vehicle is detected by the ultrasonic sensor 164, for example.

  The ultrasonic sensor 164 transmits the generated contact signal PS1 to another terminal via a wireless station connected to itself via an interface defined by P1 or P2. At this time, the contact signal PS1 is once digitized in the wireless station and transmitted as contact information to another wireless station. The other radio station generates a contact signal PS2 based on the received contact information, and transmits the generated contact signal PS2 to a terminal connected to itself.

  The central communication device 160 transmits various types of information received from the optical beacon 162, the image sensor 163, and the ultrasonic sensor 164 to the central device 251.

  Thus, for example, signal control command information, signal control execution information, contact information, VICS information, and vehicle information are included in the traffic information transmitted and received between the master station 101, the relay station 151, and the slave station 202. is there. The traffic information includes, for example, vehicle image information, vehicle speed, number of passing vehicles, and traffic jam length.

  Hereinafter, traffic information such as signal control command information, signal control execution information, VICS information, or vehicle information is also referred to as serial information. The serial information is an interface type defined in any of S4 to S6 and S9 to S11 between a terminal connected to the relay station 151 or a terminal connected to the slave station 202 and a terminal connected to the master station 101. Information transmitted and received via peer-to-peer.

  The main station 101 can transmit command information to other radio stations, for example. The command information includes, for example, a change of a channel used for transmission / reception of a radio signal, a reset of a radio station, a change of a radio signal communication speed, that is, a transmission rate and a communication method, and an in / out setting of contact information. Here, in and out of the contact information means that the contact information is inserted into the communication packet and that the contact information is extracted from the communication packet.

[Task]
For example, in a traffic control system, an allowable delay time is defined for contact signals and serial information that require real-time characteristics among those transmitted and received between terminals.

  More specifically, in the wireless communication system 301, with respect to the contact signal, any terminal is required to be able to receive the contact signal generated by another terminal within the maximum allowable time Tmaxp.

  Here, the maximum allowable time Tmaxp is, for example, for the time required for transmitting the contact signal when the terminal that transmits the contact signal and the terminal that receives the contact signal are connected by wire. This is the time after adding 400 milliseconds.

  Further, it is required that a combination of a terminal that generates a contact signal and a terminal that uses the contact signal can be arbitrarily set. In other words, there is no restriction on the terminal that uses the contact signal generated in the ultrasonic sensor 164 connected to a certain radio station.

  As for the serial information, it is required that the central communication device 160 can receive the serial information within a maximum allowable time Tmaxs after a certain terminal transmits the serial information.

  Here, the maximum allowable time Tmaxs is, for example, 200 mm with respect to the time required for transmitting the serial information when the terminal transmitting the serial information and the central communication device 160 are connected by wire. This is the time plus seconds.

  For example, in a wireless section in the wireless communication system 301, a method of transmitting and receiving communication packets including contact information and serial information using a TDMA (Time Division Multiple Access) method is conceivable. More specifically, in the TDMA system, for example, when one period is 132 milliseconds, 32 slots are generated by dividing one period by a time interval of 4 milliseconds. Then, one or a plurality of slots, which are periods during which communication packets can be transmitted, are allocated to the wireless station.

  Since each radio station transmits a communication packet in one or a plurality of slots allocated to itself, it is possible to prevent interference from occurring due to a plurality of radio stations transmitting communication packets at the same time.

  However, in the TDMA system, strict time synchronization is required between wireless stations in a communication system. For example, when a radio station synchronizes time by exchanging signals with other radio stations using dedicated hardware, or based on time information acquired from a GPS (Global Positioning System) satellite Although it is possible to synchronize the time of each radio station with an error of about 1 microsecond, the dedicated hardware for these synchronization processes is expensive, which increases the cost.

  In addition, when time synchronization is performed using low-cost general-purpose hardware such as a commercially available wireless LAN module instead of using dedicated hardware, the following problems occur in a driver for operating general-purpose hardware, that is, software. . That is, a delay due to the processing time in the software, a variation in the processing time, and the like occur, and the accuracy of time synchronization deteriorates to about several tens of milliseconds, for example. For this reason, it becomes difficult to perform communication according to the TDMA system using general-purpose hardware.

  For example, when the first 16 slots of one cycle are used for downlink communication from the master station to the slave station, and when the latter 16 slots are used for uplink communication from the slave station to the master station, the communication packet is And each slave station can only make one round trip per cycle. In particular, when the number of slave stations is small, since the substantial amount of information transmitted per cycle is small, the efficiency of communication packet transmission / reception deteriorates.

  In addition, for example, the slot length of each slot is set to be long so that wireless communication between wireless stations can be completed within the range of the slot length regardless of the size of the exchanged data size. . For this reason, even if the relay station completes reception of a communication packet from another wireless station at an early timing of a certain slot, for example, the relay station may transmit the communication packet to the next wireless station until the next slot is started. Can not. Therefore, when data is exchanged via a plurality of relay stations, the time during which wireless communication is not performed increases, and the time utilization efficiency deteriorates.

  Further, for example, a method of transmitting and receiving communication packets using a CSMA / CA (Carrier Sense Multiple Access with Collision Avidance) method is conceivable. More specifically, in the CSMA / CA method, for example, a wireless station determines whether or not other wireless stations are transmitting radio waves, and determines that other wireless stations are not transmitting radio waves. In addition, a radio wave including a communication packet is transmitted. Thereby, it can avoid that interference arises because a some radio station transmits an electromagnetic wave simultaneously.

  However, in the CSMA / CA method, when it is determined that another radio station is transmitting radio waves, the radio station waits until the other radio station stops transmitting radio waves. Since the communication packet is not transmitted to the next station while the wireless station is waiting, the arrival time of the communication packet at the destination is delayed.

  For this reason, the delay time of a communication packet may exceed the delay time prescribed | regulated by a traffic control system, and is unpreferable. That is, in the CSMA / CA system, it is difficult to ensure punctuality.

  In addition, for example, when a communication failure occurs in a wireless communication system, an operator needs to grasp a communication state between wireless stations. At this time, for example, the worker connects a PC (Personal Computer) or the like to a certain radio station and captures the communication status between the radio stations into the PC. The latest communication status captured in the PC is more preferable. Further, the command information transmitted from the main station 101 to other stations is preferably as new as possible.

  Therefore, the wireless communication system according to the first embodiment of the present invention solves such problems by the following configuration and operation.

  FIG. 4 is a diagram illustrating an example of a communication packet transmitted / received by a wireless station configuring the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 4, a communication packet is composed of, for example, “wireless LAN header (Ether header)”, “RSSI / NOISE”, “wireless application header (wireless AP header)”, and “message payload” in the order of transmission. Is done.

  The “wireless LAN header” can store a transmission destination MAC address, a transmission source MAC address, and a data type. “RSSI / NOISE” can store an RSSI value and a noise level measured in the physical layer in the communication protocol of the wireless station when a communication packet is received.

  The “wireless AP header” includes a version field, an identifier field, a use CH field, a transmission method field, a transmission destination field, a transmission source field, a retransmission number field, a retransmission number field, and a serial number field. The number of bits indicating is 8, 4, 4, 8, 4, 4, 8, 8, and 16, respectively.

  The most significant bit in the “identifier” field stores a value indicating the type of communication packet. When the value is zero, the type of communication packet is a control packet CP used for command collection and status collection for each wireless station. When the value is 1, the communication packet type is a serial packet SP used for transmission of serial information. Become. Other values stored in each field will be described later. The communication packet may include other types of packets other than the control packet CP and the serial packet SP.

  When the type of the communication packet is the control packet CP, the “message payload” includes a control message reception bit field, a radio state field, a contact information field, and a control message field. Communication quality information such as an RSSI value and a noise level measured by each radio station can be stored in the radio status field.

  The contact information field can store contact information acquired by each wireless station, the amount of the contact information, and a status indicating whether the contact information is valid. Command information can be stored in the control message field. In the “message payload”, serial information can be stored when the type of the communication packet is the serial packet SP.

  FIG. 5 is a diagram illustrating an example of communication packet transmission in the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 5, master station 101, relay station 151, and slave station 202 transmit and receive, for example, control packet CP as a communication packet.

  In the wireless communication system 301, for example, the control packet CP can pass through all wireless stations.

  For example, in the wireless communication system 301, the control packet CP transmitted from the master station 101 can return to the master station 101 via all the relay stations 151 and slave stations 202, as indicated by the thick arrows in FIG. It is.

  Each relay station 151 and each slave station 202 can acquire contact information and command information from the control packet CP, and can include contact information, a response to the command information, and communication quality information in the control packet CP. The main station 101 can acquire contact information, a response to command information, and communication quality information from the control packet CP, and can include the contact information and command information in the control packet CP.

  Specifically, the control packet CP is transmitted from the main station 101 once at the start timing of one cycle. The control packet CP transmitted from the master station 101 returns to the master station 101 via all relay stations 151 and slave stations 202. The length of one cycle is, for example, set as a default value of 200 milliseconds and is variable. The sampling period of contact information is, for example, 10 milliseconds. In this case, contact information for 20 samples is included in one control packet CP, for example. When the control packet CP does not return, the main station 101 performs a retransmission process for the control packet CP. For example, the retransmission process is performed one or more times, and an upper limit of the number of processes is set according to the number of radio stations configuring the radio communication system 301.

  The control packet CP plays a role of health check for checking whether the communication packet periodically circulates through all the radio stations.

  FIG. 6 is a diagram illustrating an example of communication packet transmission in the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 6, master station 101, relay station 151, and slave station 202 transmit and receive serial packets SP, for example, as communication packets.

  Serial information can be stored in the serial packet SP. The serial information is, for example, information from a terminal connected to the master station 101, the relay station 151, or the slave station 202, which is different from the contact information included in the control packet CP. Specifically, the serial information includes traffic information such as signal control command information, signal control execution information, VICS information, or vehicle information. For example, the serial packet SP may include only traffic information other than information for wireless control, or may include other information.

  In the wireless communication system 301, transmission / reception is performed between the relay station 151 or the slave station 202 corresponding to the serial packet SP and the master station 101.

  Specifically, for example, the serial packet SP is transmitted from the main station 101 at regular intervals from when the control packet CP returns to the main station 101 until one cycle ends. The length of the constant interval is variable, for example, 10 milliseconds is set as a default value.

  Each wireless station can transmit serial information of four serial channels in parallel, for example. For example, the radio station transmits serial packets SP in order for each serial channel. The serial packet SP is transmitted / received between the master station 101 and the relay station 151 or the slave station 202 according to a peer-to-peer method.

  In FIG. 6, the serial channel SCh1 is allocated between the terminal A and the terminal C, the serial channel SCh2 is allocated between the terminal A and the terminal D, the serial channel SCh3 is allocated between the terminal A and the terminal F, and the terminal A and the terminal A serial channel SCh4 is allocated between G, and an example in which the slave station 202 connected to the terminal F and the terminal G processes serial packets SP for two serial channels is shown.

  When the serial packet SP includes information according to FTP (File Transfer Protocol) and information according to Telnet as the other information, for example, file transfer and remote operation can be performed between the terminal A and the terminal C, respectively.

  The slave station 202 connected to the terminal E does not transmit / receive the serial packet SP to / from the master station 101 because the serial channel is not assigned. In addition, each wireless station in the wireless communication system 301 transmits / receives the control packet CP regardless of whether contact information is in / out, for example.

  FIG. 7 is a diagram showing a configuration of a wireless communication apparatus in the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 7, a wireless communication device 91 can be used as a master station 101, a relay station 151, or a slave station 202, and includes an antenna 10, a wireless communication unit 11, a wired communication unit 12, and a packet processing unit 13. , An operation unit 14, an external command processing unit 15, a contact information processing unit 16, a storage unit 17, and an output unit 20. The packet processing unit 13 includes a packet route determination unit 31, a packet management unit 32, a serial packet processing unit 33, a control packet processing unit 34, and a transmission failure number counter unit 39. The storage unit 17 includes a contact information first buffer 18 and a contact information second buffer 19.

  The storage unit 17 stores, for example, an entry table indicating the network configuration of each wireless station in the wireless communication system 301, communication packet contents, contact information, a communication quality information log indicating a history of communication quality information, and various setting information. Is possible. The master station 101, the slave station 202, and the relay station 151 store the same entry table.

  FIG. 8 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention.

  FIG. 9 is a diagram showing an example of an entry table stored in the storage unit according to the first embodiment of the present invention.

  Referring to FIG. 8 and FIG. 9, the entry table includes an interface for each station configuration that is a set of a master station 101 and a slave station 202 connected in series with the common master station 101 in the wireless communication system 301 as one end point. The type, destination station and transit station are stored.

  More specifically, the interface type indicates the type of information to be transmitted, and specifically includes P1 and P2 corresponding to contact information, S4 to S6 and S9 to S11 corresponding to serial information, and the like.

  The destination station is a station number of a radio station located at a different end point from the main station in the corresponding station configuration. The transit station represents the station numbers of wireless stations located on the communication path from the main station 101 to the destination station in order of transit. In the communication system 301, the same station number is not assigned to different radio stations.

  Specifically, for example, the entry table used in each wireless station in the wireless communication system 301 shown in FIG. 8 includes S6, station number 1 and station numbers 2, 3, as the interface type, destination station, and transit station of station configuration 1. 4 is stored. Further, S4, station number 3 and station number 2 are stored as the interface type, destination station and relay station of station configuration 2, respectively. Further, S6, station number 5 and station number 6 are stored as the interface type, destination station and relay station of station configuration 3, respectively. Further, P1, station number 7, and station number zero are stored as the interface type, destination station, and relay station of station configuration 4, respectively. Here, the station number zero indicates that there is no transit station. Further, S5, station number 8, and station number zero are stored as the interface type, destination station, and relay station of station configuration 5, respectively.

  That is, a serial packet SP including serial information corresponding to S6 is exchanged between the master station 101 having the station number 9 and the slave station 202 having the station number 1, with the radio stations having the station numbers 2, 3, and 4 as the relay station 151. In addition, a serial packet SP including serial information corresponding to S4 is exchanged between the master station 101 and the slave station 202 with the station number 3 by using the wireless station with the station number 2 as the relay station 151.

  Therefore, when the serial packet SP is exchanged between the master station 101 and the slave station 202 with the station number 1, the radio station with the station number 3 performs the relay process of the serial packet SP, and between the master station 101 and itself. When the serial packet SP is exchanged at, slave station processing is performed. The relay process and the slave station process will be described later.

  In addition, a serial packet SP including serial information corresponding to S6 is exchanged between the master station 101 and the slave station 202 with the station number 5 by using the wireless station with the station number 6 as the relay station 151.

  Between the master station 101 and the slave station 202 of the station number 7, serial information is not registered with the interface type, so the serial packet SP is not exchanged, but the control packet CP is exchanged.

  Further, a serial packet SP including serial information corresponding to S5 is directly exchanged between the master station 101 and the slave station 202 of station number 8.

  For example, the communication paths specified by the station configurations 1, 2, 3, and 5 in which serial information is specified as the interface type correspond to the communication paths corresponding to the serial channels SCh1, SCh2, SCh3, and SCh4, respectively.

  Referring to FIG. 7 again, radio communication unit 11 converts the frequency of a radio signal received from antenna 10 from another radio station into a baseband signal, for example, and converts the frequency-converted signal into a digital signal. And the wireless communication part 11 produces | generates a communication packet by performing various signal processing with respect to the converted digital signal.

  At this time, the wireless communication unit 11 stores, for example, the RSSI value and noise level measured at the time of receiving the communication packet in “RSSI / NOISE” in the communication packet. The wireless communication unit 11 outputs the generated communication packet to the packet processing unit 13. This communication packet includes traffic information and the like.

  Further, the wireless communication unit 11 holds a correspondence table between the MAC address and station number of each wireless station, and based on the transmission source MAC address stored in the “wireless LAN header” and the correspondence table, the communication packet The packet processing unit 13 is notified of the station number of the transmission source wireless station that is the wireless station that transmitted the last.

  The wired communication unit 12 converts part or all of the digital signal received from the packet processing unit 13 into a predetermined frame format and transmits the converted signal to the terminal via a wire.

  Further, the wired communication unit 12 outputs a part or all of data in a predetermined frame format received from the terminal to the packet processing unit 13 and the contact information processing unit 16. This data includes traffic information and the like.

  The wireless communication unit 11 performs various signal processing on the communication packet received from the packet processing unit 13, that is, data that is a digital signal. At this time, for example, based on the correspondence table, the wireless communication unit 11 uses, as the transmission destination MAC address, the MAC address corresponding to the transmission destination station number that is the station number of the wireless station to be transmitted next received from the packet processing unit 13. Stored in “wireless LAN header”. The radio communication unit 11 converts the digital signal after the signal processing into an analog signal, converts the frequency of the converted analog signal into a radio signal, and outputs the radio signal to the antenna 10.

  The radio communication unit 11 can change the frequency channel, transmission rate, and communication method of the radio signal according to the control of the external command processing unit 15, for example.

  The operation unit 14 receives an operation from the user for the wireless communication device 91 and outputs operation information indicating the content of the operation to the external command processing unit 15.

  The operations include, for example, a radio station number setting operation, a transmission rate change operation and a communication method change operation performed when the transmission rate is high and the frequency of communication errors is high, and the frequency of communication errors due to interference is high. There are a change operation of a frequency channel of a radio signal performed, an entry table input operation, a radio station designation operation for performing contact information in, a radio station designation operation for performing contact information out, and the like. In addition, the said communication system is IEEE802.11a, IEEE802.11b, and IEEE802.11g, for example.

  The external command processing unit 15 performs setting processing, operation change processing, information output processing, and the like of its own wireless communication device 92 according to operation information received from the operation unit 14. Specifically, the external command processing unit 15 sets the station number of its own wireless communication device 92 according to operation information received from the operation unit 14, for example. At this time, the external command processing unit 15 switches the operation mode of its own wireless communication device 91 to the master station mode or the slave station mode according to the set station number.

  Specifically, for example, when the station number after setting is 0x09, the external command processing unit 15 switches the operation mode to the master station mode. Hereinafter, a number starting with “0x” means that the number after “0x” is expressed in hexadecimal. At this time, the wireless communication device 92 becomes the main station 101.

  The external command processing unit 15 switches the operation mode to the slave station mode, for example, when the station number after setting is any of 0x01 to 0x08. At this time, the wireless communication device 92 becomes the relay station 151 or the slave station 202.

  The wireless communication device 91 is configured to be the master station 101, the relay station 151, or the slave station 202 according to the station number set for itself, but is not limited thereto. For example, the wireless communication device 91 may be usable as only one or any two of the master station 101, the relay station 151, and the slave station 202 according to the station number set for itself.

  Also, the external command processing unit 15 creates command information for controlling other radio stations in accordance with the operation information received from the operation unit 14 in the master station mode, for example. The command information includes radio signal frequency channel, transmission rate and communication system change, radio station reset, entry table update, contact information in and out settings, and the like. The external command processing unit 15 transmits the created command information to the relay station 151 and the slave station 202 via the packet processing unit 13. Note that the external command processing unit 15 is not limited to the operation unit 14 when the wireless communication device 91 has acquired the transmission right for transmitting command information to other wireless stations, for example, even in the slave station mode. Command information may be created according to the received operation information, and the created command information may be transmitted to another wireless station.

  The external command processing unit 15 receives command information from the main station 101 via the packet processing unit 13 in the slave station mode, for example.

  For example, if the command information includes content regarding the change of the frequency channel, transmission rate, and communication method of the radio signal, the external command processing unit 15 changes the operation setting of the radio communication unit 11 according to the content. Also, the external command processing unit 15 resets its own wireless communication device 91, for example, when the command information includes the contents regarding the resetting of the wireless station.

  In addition, for example, when the command information includes content about updating the entry table, the external command processing unit 15 updates the entry table in the storage unit 17 according to the content.

  In addition, for example, when the command information includes the information about the in / out setting of the contact information, the external command processing unit 15 performs the contact in setting and the contact out setting of its own wireless communication device 91 according to the content. Switch.

  Specifically, for example, when the content of the command information indicates that the contact information should be input, the external command processing unit 15 switches the contact in setting to ON, and the content of the command information inputs the contact information. If it indicates that it should not, switch the contact in setting off. Similarly, for example, when the content of command information indicates that contact information should be output, the external command processing unit 15 switches the contact out setting to ON, and the content of command information should not output contact information. If so, the contact out setting is switched off.

  Further, the external command processing unit 15 can output the storage contents of the storage unit 17 to the output unit 20 in accordance with, for example, operation information received from the operation unit 14.

  The output unit 20 is, for example, a light emitting element such as an LED (Light Emitting Diode) and a 7-segment LED arranged in a line, and according to the content of information received from the external command processing unit 15 according to a predetermined method Turn on the light. The output unit 20 may be a terminal for outputting information received from the external command processing unit 15, for example.

  When the contact in setting is ON, the contact information processing unit 16 samples the contact signal received from the terminal via the wired communication unit 12 with a period of, for example, 10 milliseconds, and stores the contact information that is a sampled digital signal as a storage unit 17 is alternately stored in the contact information first buffer 18 and the contact information second buffer 19.

  More specifically, for example, when the contact information storage destination is the contact information first buffer 18, the contact information processing unit 16 receives, from the packet processing unit 13, transshipment information indicating a timing for transposing contact information. The following processing is performed. That is, for example, after clearing the stored contents of the contact information second buffer 19, the contact information processing unit 16 switches the contact information storage destination to the contact information second buffer 19 and indicates a new storage destination of the contact information. The storage destination information is notified to the packet processing unit 13.

  In addition, for example, when the contact information storage destination is the contact information second buffer 19, the contact information processing unit 16 performs the following processing when receiving the transshipment information from the packet processing unit 13. That is, for example, after clearing the stored contents of the contact information first buffer 18, the contact information processing unit 16 switches the storage destination of the contact information to the contact information first buffer 18 and transfers the storage destination information to the packet processing unit 13. Notice.

  The contact information processing unit 16 receives the contact information included in the new control packet CP from the packet processing unit 13 when the contact out setting of its own wireless communication device 91 is on. The contact information processing unit 16 generates a contact signal based on the contact information received from the packet processing unit 13 and transmits the generated contact signal to the terminal via the wired communication unit 12.

[Communication packet reception processing]
When the packet route determination unit 31 in the packet processing unit 13 receives a communication packet via the wireless communication unit 11, it refers to the value stored in the most significant bit of the identifier field of the received communication packet, and the type of the communication packet is serial. It is confirmed whether it is a packet SP or a control packet CP.

  For example, when the type of communication packet is a serial packet SP and the wireless communication device 91 is in the master station mode, the packet path determination unit 31 outputs the received serial packet SP to the packet management unit 32. When the wireless communication device 91 is in the slave station mode, the received serial packet SP is output to the serial packet processing unit 33.

  In addition, when the type of the communication packet is the control packet CP, the packet route determination unit 31 determines whether the received control packet CP is the control packet CP having the wireless communication device 91 as a terminal station or other wireless communication It is confirmed whether the control packet CP is to be relayed to the device 91.

  For example, in the case of the network configuration shown in FIG. 8, the control packet CP is indicated by a thick line arrow from the main station 101 of station number 9 to station numbers 2, 3, 4, 1, 4, 3, 2, 9, 6, 5, When transmitted so as to return to the main station of station No. 9 via the radio stations 6, 9, 7, 9, 8 in this order, the control packet CP having its own radio communication device 91 as the terminal station and the other The control packet CP to be relayed to the wireless communication device 91 is as follows.

  That is, the control packet CP having the wireless communication device 91 as its terminal station is a control packet CP received by the master station 101 having the station number 9 from the slave station 202 having the station number 8.

  The control packet CP to be relayed to the other wireless communication device 91 includes the control packet CP received by the relay station 151 and the slave station 202, and the relay station 151 of the station numbers 2 and 6 or the slave station 202 of the station number 7 of the master station 101. Is a control packet CP received from.

  The packet path determination unit 31 is based on the transmission destination field of the control packet CP received via the wireless communication unit 11, the station number of the transmission source wireless station notified from the wireless communication unit 11 together with the control packet CP, and the entry table. Check.

  As a result of the above confirmation, the packet path determination unit 31 outputs the received control packet CP to the packet management unit 32 when the received control packet CP is a control packet CP having its own wireless communication device 91 as a terminating station. To do.

  Further, when the received control packet CP is a control packet CP to be relayed to another wireless communication device 91, the packet path determination unit 31 sends the station number of the transmission source radio station and the control packet CP to the control packet processing unit 34. Output. At this time, the packet path determination unit 31 stores the station number of the transmission source radio station in association with the value stored in the serial number field of the control packet CP in the storage unit 17.

[Communication packet route determination and transmission process 1]
When receiving the communication packet from the packet management unit 32, the serial packet processing unit 33, and the control packet processing unit 34, the packet path determination unit 31 sets the station number of the wireless station to which the received communication packet is to be transmitted, The communication packet is transmitted to the radio station.

  Specifically, for example, when the packet route determination unit 31 receives the serial packet SP from the packet management unit 32 or the serial packet processing unit 33, the packet path determination unit 31 stores the destination wireless station stored in the transmission destination field in the received serial packet SP. Get the station number. Then, the packet path determination unit 31 sets the transmission destination station number based on the acquired station number of the transmission destination wireless station, the station number of its own wireless communication device 91 and the entry table, and the serial number together with the set transmission destination station number. The packet SP is output to the wireless communication unit 11.

  Further, for example, when receiving the control packet CP from the packet management unit 32, the packet route determination unit 31 sets a transmission destination station number based on the entry table, and transmits the control packet CP together with the set transmission destination station number to the wireless communication unit. 11 to output.

  The transmission destination station number setting process for the control packet CP received by the packet route determination unit 31 from the control packet processing unit 34 will be described later.

  Further, the packet path determination unit 31 receives, for example, ACK indicating that the communication packet output to the wireless communication unit 11 has been received by the transmission destination wireless station from the transmission destination wireless station via the wireless communication unit 11. It is possible.

  The transmission failure number counter unit 39 includes a counter provided corresponding to the station number of the wireless station, for example. For example, if the packet route determination unit 31 cannot receive an ACK for the control packet CP from the transmission destination wireless station even if the control packet CP is transmitted via the wireless communication unit 11, the packet route determination unit 31 performs the transmission in the transmission failure number counter unit 39. The counter value corresponding to the station number of the previous wireless station is incremented.

  In addition, for example, when the packet route determination unit 31 transmits a control packet CP via the wireless communication unit 11 and can receive an ACK for the control packet CP from the transmission destination wireless station, the packet route determination unit 31 The counter value corresponding to the station number of the destination wireless station is reset to zero.

[Master station processing]
FIG. 10 is a diagram showing a configuration of the packet management unit in the packet processing unit according to the first embodiment of the present invention.

  Referring to FIG. 10, packet management unit 32 includes a serial packet management unit 35, a control packet management unit 36, a timer 37, and a schedule creation unit 38. The timer 37 outputs a trigger signal every 10 milliseconds, for example.

  The wireless communication device 91 becomes the main station 101 in the master station mode, and generates a control packet CP and a serial packet SP, for example, and performs a main station process for managing the transmission timing of the generated control packet CP and serial packet SP.

(Schedule creation)
The schedule creation unit 38 in the packet management unit 32 creates a communication schedule for managing the transmission timing of communication packets. More specifically, for example, the schedule creation unit 38 sets a slot by setting a transmission cycle and dividing the set transmission cycle at a predetermined interval. The schedule creation unit 38 creates a communication schedule based on the set transmission cycle and slot, for example. For example, the transmission cycle is set to ½ or less of the maximum allowable time of the control packet CP.

  Specifically, the schedule creation unit 38 sets the transmission cycle to 200 milliseconds, for example. For example, the schedule creation unit 38 divides the transmission period evenly into 20 slots and assigns each slot having a time interval of 10 milliseconds to the transmission of the control packet CP and the transmission of the serial packet SP, or the NOP A communication schedule is created by setting (No Operation). Here, the new control packet CP and serial packet SP are not transmitted in the slot set to NOP. The transmission cycle and the number of slots included in the transmission cycle are variable.

  The schedule creation unit 38 sets the maximum number of retransmissions of the control packet CP according to the number of wireless stations that make up the wireless communication system 301. Specifically, the schedule creation unit 38 refers to an entry table stored in the storage unit 17 and has a station configuration in which serial information is assigned to the number of radio stations in the radio communication system 301 and the interface type. Check whether or not.

  For example, when there is a station configuration in which serial information is assigned to the interface type, the schedule creation unit 38 recognizes that the serial communication SP is transmitted and received in the wireless communication system 301 and sets the following maximum number of retransmissions.

  That is, for example, when the number of constituents is 4 or less, 5 or more and 8 or less, or 9 at the maximum, the schedule creation unit 38 sets the maximum number of retransmissions to 4, 3, or 2, respectively. Note that the maximum number of retransmissions when the serial packet SP is not transmitted / received will be described later.

  Further, the schedule creation unit 38 sets the retransmission interval of the control packet CP to a length corresponding to the number of wireless stations that should transmit the control packet CP in the wireless communication system 301. Specifically, the schedule creation unit 38 sets the number of NOPs for the control packet CP according to the number of radio stations that constitute the radio communication system 301.

  Specifically, for example, when the number of components is 4 or less, 5 or more and 8 or less, or the maximum of 9 units, the schedule creation unit 38 sets the number of NOPs for the control packet CP to zero, 1 or 2 Set each.

  FIG. 11 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 11 shows a case where the length of one cycle is 200 milliseconds and the time length of the zeroth to 19th slots, that is, one square shown in the figure is 10 milliseconds.

  Referring to FIG. 11, for example, the schedule creation unit 38 can transmit the serial packet SP in a period in which the control packet CP is periodically transmitted and the control packet CP is not transmitted in the transmission period of the control packet CP. The communication schedule is created so that the control packet CP is transmitted before the serial packet SP in each transmission cycle.

  Specifically, hereinafter, the control packet CP transmitted first in each cycle is also referred to as a control packet CP0. Further, the control packets CP retransmitted for the first to fourth times in each cycle are also referred to as control packets CP1 to CP4, respectively. The control packet CP0 is always transmitted every transmission cycle. The control packets CP1 to CP4 may be transmitted every transmission cycle or may not be transmitted. Serial packets SP including serial information corresponding to serial channels SCh1 to SCh4 are also referred to as serial packets SP1 to SP4, respectively.

  When the number of constituents is four or less, the schedule creation unit 38 allocates, for example, five slots from the zeroth to the fourth located at the head of the communication schedule CSS0 for transmission of the control packet CP.

  More specifically, the schedule creation unit 38 allocates the zeroth slot for transmission of the control packet CP0. The schedule creation unit 38 assigns the first to fourth slots to the transmission of the control packets CP1 to CP4, respectively.

  Hereinafter, the zeroth to fourth slots assigned to the rounds of the control packets CP0 to CP4 are also referred to as slots RS0 to RS4.

  For example, the schedule creation unit 38 allocates the fifth to 19th slots for transmission of the serial packet SP.

  For example, when serial information is registered in the entry table, the schedule creation unit 38 assigns slots so that serial packets SP including corresponding serial information are transmitted in the order of serial channel numbers corresponding to the serial information. .

  Specifically, as shown in FIG. 11, for example, when the serial channels SCh1 to SCh4 are assigned in the entry table, the schedule creation unit 38 uses the fifth to eighth slots to transmit the serial packets SP1 to SP4. Assign each. Similarly, the schedule creation unit 38 assigns the ninth to twelfth slots for transmission of the serial packets SP1 to SP4, respectively.

  Similarly, the schedule creation unit 38 assigns the 13th and subsequent slots to the transmission of the serial packets SP1 to SP4, and assigns the last 19th slot to the transmission of the serial packet SP3.

  FIG. 12 is a diagram illustrating an example of a communication schedule for three consecutive periods created by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 12 shows the communication schedule CSS0 shown in FIG. 11 and the communication schedules CSS1 and CSS2 following the communication schedule CSS0.

  For example, when the schedule creating unit 38 assigns the 19th slot, which is the last slot in the communication schedule CSS0, to the transmission of the serial packet SP3, it is the slot for the first serial packet SP in the communication schedule CSS1 of the next cycle. The th slot is assigned to the transmission of the serial packet SP4, for example. Then, the schedule creation unit 38 assigns the sixth and subsequent slots in the communication schedule CSS1 to the transmission of the serial packets SP1 to SP4 as in the case shown in FIG. 11, and assigns the last 19th slot to the transmission of the serial packet SP2. .

  For example, the schedule creation unit 38 allocates the fifth slot, which is the slot for the first serial packet SP in the communication schedule CSS2 in the cycle next to the cycle of the communication schedule CSS1, to the transmission of the serial packet SP3, for example. Then, the schedule creation unit 38 assigns the sixth and later in the communication schedule CSS2 to the transmission of the serial packets SP1 to SP4 as in the case shown in FIG. 11, and assigns the last 19th slot to the transmission of the serial packet SP1.

  As described above, the number of serial channel numbers is increased or decreased by the configuration in which slots are allocated so that serial packets SP including serial information corresponding to the serial channel number order are transmitted regardless of whether or not two consecutive cycles are crossed. Regardless of this, the redundancy of serial information can be equally provided.

  FIG. 13 is a diagram illustrating an example of a communication schedule changed by the main station of the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 13, transmission of serial packet SP is started when a predetermined condition is satisfied. Specifically, the predetermined condition is that the control packet CP returns to the master station 101 via the slave station 202 or the relay station 151.

  For example, when the predetermined condition is satisfied, the schedule creation unit 38 changes the communication schedule. More specifically, for example, when receiving the control packet reception information from the packet management unit 32 in the zeroth to fourth slots of the communication schedule CSS0, that is, the slots RS0 to RS4, the schedule creation unit 38 performs the following processing: .

  That is, for example, the schedule creation unit 38 changes the communication schedule CSS0 and assigns a slot after the slot in which the control packet CP is returned to the transmission of the serial packet SP. Here, the control packet reception information includes that the control packet CP transmitted in any of the slots RS0 to RS4 can return to the master station 101 via the relay station 151 and the slave station 202 within the period. .

  Specifically, when receiving the control packet reception information from the packet management unit 32 in the second slot in the communication schedule CSS0, for example, the schedule creation unit 38 sets the third and subsequent slots as serial packets as shown in the communication schedule CSS0m. Assign to send SP.

  At this time, the schedule creation unit 38 assigns slots for the third and subsequent slots so that serial packets SP including corresponding serial information are transmitted in the order of serial channel numbers.

  In this way, by confirming that the control packet CP has returned, the configuration for increasing the number of slots used for transmitting the serial packet SP increases the transmission opportunity for serial information without causing any trouble in the transmission of the control packet CP. be able to.

  The predetermined condition is that the number of retransmissions of the control packet CP has reached a predetermined value. Specifically, for example, when the schedule creation unit 38 does not receive control packet reception information from the packet management unit 32 in the zeroth to fourth slots of the communication schedule CSS0, the serial packet SP in the fifth and subsequent slots. Starts to be sent.

  FIG. 14 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 14, when the number of components is 5 or more and 8 or less, the schedule creation unit 38 controls, for example, eight slots from the zeroth to the seventh that are located at the head of the communication schedule CSM0. Assigned to send packet CP.

  More specifically, the schedule creation unit 38 assigns the zeroth slot for transmission of the control packet CP0, and sets the first slot as NOP to cope with an increase in communication time due to an increase in the number of components.

  The schedule creation unit 38 assigns the second, fourth, and sixth slots to the transmission of the control packets CP1, CP2, and CP3, respectively, and sets the third, fifth, and seventh slots as NOPs.

  As a result, regardless of the network configuration of each wireless station in the wireless communication system 301 and the data length of the control packet CP, the main station 101 confirms that the control packet CP has returned after transmitting the control packet CP. Sufficient time can be secured.

  Hereinafter, the zeroth to first, second to third, fourth to fifth, and sixth to seventh slots assigned to the rounds of the control packets CP0, CP1, CP2, and CP3 are designated as slots RS0, RS1, RS2, and so on. Also referred to as RS3.

  For example, as in the case of the communication schedule CSS0 shown in FIG. 11, the schedule creation unit 38 allocates the 8th to 19th slots for transmission of the serial packet SP.

  As in the case of the communication schedule CSS0m shown in FIG. 13, the schedule creation unit 38 receives the control packet reception information from the packet management unit 32 in the slots RS0 to RS3. When receiving control packet reception information from the packet management unit 32 in the th slot, the following processing is performed.

  That is, the schedule creation unit 38 allocates the fourth and subsequent slots for transmission of the serial packet SP. At this time, the schedule creation unit 38 assigns slots for the fourth and subsequent slots so that serial packets SP including corresponding serial information are transmitted in the order of serial channel numbers.

  FIG. 15 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 15, when the number of constituents is nine at the maximum, the schedule creation unit 38 assigns, for example, nine slots from the zeroth to the eighth that are located at the head of the communication schedule CSL0 in the control packet CP. Assign to send.

  More specifically, the schedule creation unit 38 assigns the zeroth slot for transmission of the control packet CP0, and sets the first and second slots as NOPs in order to cope with an increase in communication time due to an increase in the number of components.

  The schedule creation unit 38 assigns the third and sixth slots to the transmission of the control packets CP1 and CP2, respectively, and sets the fourth to fifth and seventh to eighth slots as NOPs.

  As a result, regardless of the network configuration of each wireless station in the wireless communication system 301 and the size of the control packet CP, the main station 101 confirms that the control packet CP has returned after transmitting the control packet CP. Sufficient time can be secured.

  Hereinafter, the zeroth to second, third to fifth slots, and the sixth to eighth slots respectively assigned to the rounds of the control packets CP0, CP1, and CP2 are also referred to as slots RS0, RS1, and RS2.

  For example, as in the case of the communication schedule CSS0 shown in FIG. 11, the schedule creation unit 38 allocates the ninth to nineteenth slots for transmission of the serial packet SP.

  Similarly to the case of the communication schedule CSS0m shown in FIG. 13, the schedule creation unit 38 receives the control packet reception information from the packet management unit 32 in the slots RS0 to RS2, specifically, for example, the third, fourth, When control packet reception information is received from the packet management unit 32 in the fifth or fifth slot, the following processing is performed.

  That is, the schedule creation unit 38 allocates the sixth and subsequent slots for transmission of the serial packet SP. At this time, the schedule creation unit 38 assigns slots for the sixth and subsequent slots so that serial packets SP including corresponding serial information are transmitted in the order of serial channel numbers.

  FIG. 16 is a diagram illustrating an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 16 shows a communication schedule when serial channel SCh1 is assigned when the number of constituents is four or less.

  Referring to FIG. 16, schedule creation unit 38 allocates five slots from zero to fourth located at the head of communication schedule CSS3 for transmission of control packet CP. Then, the schedule creation unit 38 assigns, for example, the 5th to 19th slots to the transmission of the serial packet SP1.

  For example, in the first slot, the schedule creation unit 38 performs the following processing when receiving control packet reception information from the packet management unit 32. That is, the schedule creation unit 38 assigns the second and subsequent slots to the transmission of the serial packet SP1 as shown in the communication schedule CSS3m, for example.

  FIG. 17 is a diagram showing an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 17 shows a communication schedule when serial channels SCh1 and SCh2 are assigned when the number of constituents is four or less.

  Referring to FIG. 17, schedule creation unit 38 allocates five slots from zero to fourth located at the head of communication schedule CSS4 for transmission of control packet CP. Then, the schedule creation unit 38 allocates, for example, the 5th to 19th slots for transmission of the serial packets SP1 and SP2.

  For example, when receiving the control packet reception information from the packet management unit 32 in the second slot, the schedule creation unit 38 performs the following processing. That is, the schedule creation unit 38 assigns the third and subsequent slots to the transmission of the serial packets SP1 and SP2, for example, as shown in the communication schedule CSS4m.

  FIG. 18 is a diagram illustrating an example of a communication schedule created and changed by the main station of the wireless communication system according to the first embodiment of the present invention. FIG. 18 shows a communication schedule when serial channels SCh2 to SCh4 are assigned when the number of constituents is four or less.

  Referring to FIG. 18, schedule creation unit 38 allocates five slots from zero to fourth located at the head of communication schedule CSS5 for transmission of control packet CP. Then, the schedule creation unit 38 allocates, for example, the 5th to 19th slots for transmission of the serial packets SP2, SP3, SP4.

  For example, when receiving the control packet reception information from the packet management unit 32 in the first slot, the schedule creation unit 38 performs the following processing. That is, the schedule creation unit 38 assigns the second and subsequent slots to the transmission of the serial packets SP2, SP3, SP4, for example, as shown in the communication schedule CSS5m.

  FIG. 19 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention. Hereinafter, the control packets CP that are retransmitted at the 5th to 19th times in each cycle are also referred to as control packets CP5 to CP19, respectively.

  Referring to FIG. 19, for example, when the radio communication system 301 does not transmit the serial packet SP, the schedule creation unit 38 sets the maximum number of retransmissions to the maximum number that can be retransmitted in the transmission cycle.

  Specifically, the schedule creation unit 38 refers to the entry table stored in the storage unit 17, and when there is no station configuration in which serial information is assigned to the interface type, the wireless communication system 301 transmits the serial packet SP. The maximum number of retransmissions is set to the maximum number of times that can be retransmitted in the transmission cycle.

  Specifically, for example, when the number of constituents is 4 or less, the schedule creation unit 38 sets the maximum number of retransmissions to 19 because the number of NOPs for the control packet CP is zero. Then, for example, as shown in the communication schedule CSmax1, the schedule creation unit 38 allocates 20 slots from the zeroth to the 19th located at the head of one cycle T for transmission of the control packet CP.

  For example, when the number of components is 5 or more and 8 or less, the schedule creation unit 38 sets the maximum number of retransmissions to 9 because the number of NOPs for the control packet CP is 1. Then, for example, as shown in the communication schedule CSmax2, the schedule creation unit 38 allocates 20 slots from the zeroth to the 19th located at the head of one cycle T for transmission of the control packet CP.

  In addition, for example, when the number of components is nine at the maximum, the schedule creation unit 38 sets the maximum number of retransmissions to five because the number of NOPs for the control packet CP is two. Then, for example, as shown in the communication schedule CSmax3, the schedule creation unit 38 allocates 18 slots from the zeroth to the 17th located at the head of one cycle T for transmission of the control packet CP.

  For example, even if the remaining 18th slot is assigned to transmission of the control packet CP6 and the 19th slot is NOP, the schedule creation unit 38 cannot make the 0th slot of the next cycle NOP. . For this reason, the schedule preparation part 38 makes 18th-19th slot NOP, for example. Further, for example, when the 0th slot of the next cycle can be set as NOP, the schedule creating unit 38 may assign the 18th slot to the transmission of the control packet CP6.

  For example, when the schedule creation unit 38 receives control packet reception information from the packet management unit 32 in any of the slots assigned to the transmission of the control packet CP, the schedule creation unit 38 performs the following processing. That is, the schedule creation unit 38 changes the communication schedule, and for example, cancels the allocation of slots after the slot that received the control packet reception information from the packet management unit 32. That is, the new control packet CP and serial packet SP are not transmitted in the subsequent slot.

(Schedule setting when transmission rate is changed)
For example, the schedule creation unit 38 creates a communication schedule so that serial packets SP are transmitted at intervals. At this time, for example, the schedule creation unit 38 sets the transmission interval of the serial packet SP to a length corresponding to the transmission rate of the traffic information. Specifically, the schedule creation unit 38 sets the NOP for the serial packet SP, for example, according to the transmission rate and communication method used in the wireless communication system 301.

  More specifically, each wireless station in the wireless communication system 301 transmits and receives traffic information, that is, a communication packet, at a transmission rate of 9 Mbps according to the 802.11g method by default. However, for example, when the frequency of communication errors is high, the user may change the communication method to the 802.11b method and reduce the transmission rate to 5.5 Mbps.

  When the transmission rate drops to 5.5 Mbps, the master station 101 receives the serial packet transmitted from the relay station 151 or the slave station 202 in response to the serial packet SP after the serial packet SP is transmitted by the master station 101. In some cases, the time until the time exceeds 10 milliseconds, which is the slot length.

  FIG. 20 is a diagram illustrating an example of a communication schedule for one cycle created by the main station of the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 20, for example, when the number of constituents is 4 or less and the transmission rate is lowered to 5.5 Mbps, the schedule creation unit 38 starts from the zeroth position 4 at the beginning of one cycle T. Up to the fifth slot is allocated for transmission of the control packet CP.

  Then, the schedule creation unit 38 allocates, for example, the 5th to 19th slots for transmission of the serial packet SP. More specifically, for example, when the serial channels SCh1 to SCh4 are assigned in the entry table, the schedule creation unit 38 assigns the fifth, seventh, ninth, and eleventh slots to the serial packets SP1, SP2, SP3, and SP4, respectively. The slots are assigned to transmission, and the sixth, eighth, tenth and twelfth slots are set as NOP.

  Similarly, the schedule creation unit 38 assigns the thirteenth, fifteenth, and seventeenth slots to the transmissions of the serial packets SP1, SP2, and SP3, and the 14th, sixteenth, and eighteenth slots in the NOP, for example. And As a result, the serial packets SP are transmitted at intervals.

  For example, even if the remaining 19th slot is assigned to the transmission of the serial packet SP4, the schedule creation unit 38 cannot set the 0th slot of the next cycle as a NOP. For this reason, the schedule creation unit 38 sets the 19th slot to NOP, for example.

  For example, when receiving the control packet reception information from the packet management unit 32 in any of the slots assigned to the transmission of the control packet CP, the schedule creation unit 38 performs the following processing as in the communication schedule CSS0m illustrated in FIG. . That is, for example, the schedule creation unit 38 changes the communication schedule CSS6 and assigns a slot after the slot that received the control packet reception information from the packet management unit 32 to transmission of the serial packet SP.

  Note that the schedule creation unit 38 sets, for example, a longer period determined by the slots RS0 to RS4 so that the control packet CP can travel around the radio stations in the radio communication system 301 with a margin. Therefore, the schedule creation unit 38 does not increase the number of NOPs for the control packet CP even when, for example, the communication method is changed and the transmission rate is lowered, but the present invention is not limited to this. For example, the schedule creation unit 38 may increase the number of NOPs for the control packet CP according to the transmission rate and the communication method.

  Moreover, although the schedule preparation part 38 was set as the structure which sets NOP for serial packets SP according to the transmission rate and communication system which are used in the radio | wireless communications system 301, for example, it is not limited to this.

  For example, the schedule creation unit 38 may be configured to change the transmission cycle in accordance with the transmission rate and the communication method. Specifically, for example, the schedule creation unit 38 increases the transmission period from 200 milliseconds to 400 milliseconds while maintaining the number of slots per period.

  However, when the transmission cycle is 400 milliseconds, it may be difficult to satisfy the maximum allowable time Tmaxp for the contact signal, and therefore, a configuration in which the NOP for the serial packet SP is set is preferable.

(Communication packet transmission timing by the main station)
Referring to FIG. 10 again, for example, the packet management unit 32 generates a communication packet, and transmits the generated communication packet to another wireless station via the packet route determination unit 31 according to the trigger signal and the communication schedule.

  More specifically, the packet management unit 32 recognizes each slot in the communication schedule based on, for example, a trigger signal. For example, the packet management unit 32 transmits the generated communication packet to another wireless station via the packet route determination unit 31 in the slot allocated for transmission of the communication packet.

(Control packet generation, retransmission and reception)
The control packet management unit 36 in the packet management unit 32 generates, for example, a control packet CP, and transmits the generated control packet CP to another wireless station via the packet route determination unit 31 according to the trigger signal and the communication schedule.

  More specifically, the control packet management unit 36 receives, for example, a control packet CP that circulates each wireless station in the wireless communication system 301 in the previous cycle from another wireless station via the packet path determination unit 31.

  The control packet management unit 36 generates the control packet CP0 of the next cycle by storing the following values in each field of the circulated control packet CP. Note that the control packet management unit 36 may newly generate a control packet CP0, for example, when the circulated control packet CP cannot be used.

  That is, for example, the control packet management unit 36 stores 0b0000, 0x00, 0x09, 0x09, and 0x00 in the identifier field, the used CH field, the transmission destination field, the transmission source field, and the retransmission number field, respectively. Hereinafter, a number starting with “0b” means that the number after “0b” is expressed in binary.

  In addition, when the number of wireless stations constituting the wireless communication system 301 is 4 or less, 5 or more and 8 or less, or a maximum of 9 units, the control packet management unit 36 sets, for example, 0x04, 0x03, or 0x02. Store in the number of retransmissions field. For example, the control packet management unit 36 increments the value stored in the serial number field of the control packet CP in the previous period.

  For example, when receiving the command information from the external command processing unit 15, the control packet management unit 36 stores the command information and the station number of the destination station of the command information in the control message field.

  Further, when the contact-in setting is ON, the control packet management unit 36 acquires contact information from the contact information first buffer 18 or the contact information second buffer based on the storage destination information received from the contact information processing unit 16. The acquired contact information and the amount of the contact information are stored in the contact information field. At this time, the control packet management unit 36 outputs transshipment information to the contact information processing unit 16.

  For example, in the slot RS0, the control packet management unit 36 outputs the control packet CP0 to the packet route determination unit 31 and stores a copy of the control packet CP0 in the storage unit 17.

  For example, when the control packet CP0 that circulates each wireless station in the wireless communication system 301 cannot be received from the packet route determination unit 31 by the timing when the slot RS0 expires, the control packet management unit 36 performs the following processing: . That is, the control packet management unit 36 determines that the control packet CP0 could not return to its own wireless communication device 91, that is, the master station 101 in the slot RS0 via the relay station 151, the slave station 202, or the master station 101. The following processing is performed as the first retransmission processing.

  That is, for example, the control packet management unit 36 acquires the control packet CP0 stored in the storage unit 17, increments the value stored in the retransmission number field in the acquired control packet CP0, and stores 0b0011 in the identifier field. Thus, the control packet CP1 is generated.

  Then, for example, in the slot RS1, the control packet management unit 36 outputs the generated control packet CP1 to the packet route determination unit 31, and saves a copy of the control packet CP1 in the storage unit 17.

  For example, when the control packet CP1 that circulates each wireless station in the wireless communication system 301 cannot be received from the packet route determination unit 31 by the timing when the slot RS1 expires, the control packet management unit 36 performs the following processing: . That is, the control packet management unit 36 determines that the control packet CP0 could not return to its own wireless communication device 91, that is, the master station 101 in the slot RS1 via the relay station 151, the slave station 202, or the master station 101. A second retransmission process is performed.

  For example, when the control packet management unit 36 cannot receive, from the packet path determination unit 31, the control packet CP1 that circulates each wireless station in the wireless communication system 301 by the timing at which the corresponding slot expires after the slot RS2. The following processing is performed. That is, the control packet management unit 36 determines that the control packet CP0 could not return to its own wireless communication device 91, that is, the master station 101 in the corresponding slot via the relay station 151, the slave station 202, or the master station 101. The control packet CP is retransmitted until the maximum number of retransmissions is reached.

  For example, when the control packet management unit 36 receives the control packet CP transmitted in any of the slots RS0 to RS4 from the packet route determination unit 31 before the corresponding slot period expires, the control packet management unit 36 performs the following processing. Do.

  That is, for example, the control packet management unit 36 transmits the control packet CP transmitted in any one of the slots RS0 to RS4 via its relay station 151 and slave station 202 within its own period, that is, its own wireless communication device 91, that is, the master station 101. Judge that it was possible to return to. Then, for example, the control packet management unit 36 outputs control packet reception information including a determination result to the schedule creation unit 38.

  Further, the control packet management unit 36 stores, for example, “RSSI / NOISE” in the received control packet CP, and the RSSI value and noise level of the reception section stored in the radio state field, and other radio stations, respectively. The RSSI value and the noise level are acquired as communication quality information. The control packet management unit 36 stores the acquired communication quality information in the storage unit 17 as a communication quality information log, for example.

  Also, the control packet management unit 36 acquires the amount and status of contact information from the contact information field in the received control packet CP, for example. And the control packet management part 36 acquires the contact information whose status is normal from the said contact information field based on the quantity and status of the acquired contact information, for example.

  For example, the control packet management unit 36 transmits the acquired contact information to the terminal, that is, the central communication device 160 via the wired communication unit 12, and when the contact out setting of its own wireless communication device 91 is ON, The contact information is output to the contact information processing unit 16.

(Serial packet generation, continuous transmission and reception)
The serial packet management unit 35 generates a serial packet SP, and the generated serial packet SP is wirelessly connected to a terminal that is a destination of serial information included in the serial packet SP according to a trigger signal, a communication schedule, and an entry table. The data is transmitted to the station via the packet route determination unit 31.

  More specifically, the serial packet management unit 35 receives serial information from the central communication device 160 via the wired communication unit 12, for example, and generates a serial packet SP including the received serial information in a “message payload”. Note that the serial packet management unit 35 may generate a serial packet SP that does not include the “telegram payload” when the serial information is not received from the central communication device 160 via the wired communication unit 12, for example.

  The serial packet management unit 35 stores 0b1000, 0x09, 0x00, and 0x00 in the identifier field, transmission source field, retransmission number field, and retransmission number field of the serial packet SP.

  The serial packet management unit 35 stores the serial channel number corresponding to the serial information in the use CH field. Specifically, for example, when the serial information corresponds to the serial channel SCh2, the serial packet management unit 35 stores 0x02 in the use CH field.

  For example, the serial packet management unit 35 acquires the station number of the wireless station that is the destination of the serial channel SCh2 from the entry table, and stores the acquired station number in the transmission destination field. The serial packet management unit 35 stores the serial number of the serial information in the serial number field.

  The serial packet management unit 35 outputs the generated serial packet SP to the packet path determination unit 31 according to the communication schedule set by the schedule creation unit 38.

  Specifically, the serial packet management unit 35, for example, in the communication schedule CSS0 shown in FIG. 11, the packet path determination unit 31 uses the generated serial packets SP1 to SP4 in the slots assigned to the transmission of the serial packets SP1 to SP4. To each output.

  At this time, the serial packet management unit 35 repeatedly outputs the same serial packets SP1 to SP4 to the packet path determination unit 31 until new serial information is received from the central communication device 160 via the wired communication unit 12. Process.

  Further, for example, when receiving the serial packet SP from the packet path determination unit 31, the serial packet management unit 35 determines whether or not the serial packet SP has been received in the past. At this time, the serial packet management unit 35 makes a determination based on, for example, the serial number stored in the serial number field in the serial packet SP.

  For example, when the serial packet SP has been received in the past, the serial packet management unit 35 discards the serial packet SP. For example, if the serial packet SP has not been received in the past, the serial packet management unit 35 transmits the serial information stored in the serial packet SP to the central communication device 160.

[Relay processing and slave processing]
Radio stations other than the master station 101 in the radio communication system 301, that is, the relay station 151 and the slave station 202 perform a reception-driven operation so that two or more radio stations do not transmit communication packets at the same time.

  Specifically, the wireless communication device 91 becomes the relay station 151 or the slave station 202 in the slave station mode. For example, in response to receiving the control packet CP and the serial packet SP, the relay station 151 and the slave station 202 perform relay processing for transferring or retransmitting the control packet CP and the serial packet SP to other wireless stations, respectively. In addition, the slave station 202 generates a serial packet SP and performs slave station processing to transmit the generated serial packet SP to the master station 101 in response to receiving the serial packet SP from the master station 101.

  Note that the main station 101 may perform relay processing. For example, in the case of the network configuration shown in FIG. 8, when the control packet CP is transmitted as indicated by a thick arrow, the main station 101 with the station number 9 receives the control packet CP received from the radio stations with the station numbers 2, 6, and 7. Is transferred or retransmitted to the radio stations of station numbers 6, 7, and 8, respectively.

(Relay processing of serial packet SP)
Referring to FIG. 7 again, for example, when the serial packet processing unit 33 receives the serial packet SP from the packet route determination unit 31, the received serial packet SP does not include information addressed to its own wireless communication device 91. In this case, the serial packet SP received this time is transmitted to another wireless communication device 91.

  Specifically, the serial packet processing unit 33 refers to, for example, the value stored in the transmission destination field in the received serial packet SP, that is, the station number of the wireless station that is the destination, and the station number and the own wireless communication device 91. A station number comparison process is performed to compare the station number. For example, if the station numbers do not match, the serial packet processing unit 33 recognizes that the received serial packet SP does not include information addressed to its own wireless communication device 91, and sends the serial packet SP to the packet path determination unit 31. Output.

(Slave packet SP slave processing)
In addition, the serial packet processing unit 33 includes, for example, the serial packet SP received from the packet path determination unit 31 including information addressed to its own wireless communication device 91, and the information included in the received serial packet SP is the previous time. If it is different from the information included in the received serial packet SP, the information addressed to the own wireless communication device 91 received this time is transmitted to the terminal CT connected to the own wireless communication device 91.

  In addition, the serial packet processing unit 33 includes, for example, the serial packet SP received from the packet path determination unit 31 including information addressed to its own wireless communication device 91, and the information included in the received serial packet SP is the previous time. If the information is the same as the information included in the received serial packet SP, the information addressed to the wireless communication device 91 received this time is discarded.

  Specifically, the serial packet processing unit 33 performs, for example, a station number comparison process, and if the station numbers match, recognizes that the received serial packet SP includes information addressed to its own wireless communication device 91, A serial number is acquired from the serial number field in the serial packet SP.

  For example, when the serial number acquired this time is different from the serial number acquired last time, the serial packet processing unit 33 recognizes that the information included in the serial packet SP received this time is different from the information included in the serial packet SP received last time. To do. Then, for example, the serial packet processing unit 33 acquires the serial information stored in the “message payload” in the serial packet SP received this time, and transmits the acquired serial information to the terminal CT via the wired communication unit 12.

  Further, for example, when the serial number acquired this time is the same as the serial number acquired last time, the serial packet processing unit 33 includes information included in the serial packet SP received this time and information included in the serial packet SP received last time. Are the same. In this case, the serial packet processing unit 33 does not acquire the serial information stored in the “message payload” in the serial packet SP received this time.

  In addition, the serial packet processing unit 33 generates a serial packet SP including serial information addressed to the main station 101, for example, and responds to receipt of the serial packet SP including information addressed to its own wireless communication device 91. Then, the generated serial packet SP is transmitted to the main station 101 via the packet route determination unit 31.

  More specifically, the serial packet processing unit 33 receives serial information from the terminal CT, for example, via the wired communication unit 12, and generates a serial packet SP including the received serial information in a “message payload”. Note that the serial packet processing unit 33 may generate a serial packet SP that does not include a “message payload” when serial information is not received from the terminal CT via the wired communication unit 12, for example.

  The serial packet processing unit 33 stores 0b1000, 0x09, 0x00, and 0x00 in the identifier field, transmission destination field, retransmission number field, and retransmission number field of the serial packet SP, respectively.

  The serial packet processing unit 33 stores the serial channel number corresponding to the serial information in the use CH field. Specifically, for example, when the serial information corresponds to the serial channel SCh2, the serial packet management unit 35 stores 0x02 in the use CH field.

  For example, the serial packet processing unit 33 stores the station number of its own wireless communication device 91 in the transmission source field. The serial packet management unit 35 stores the serial number corresponding to the serial information in the serial number field.

  In response to receiving the serial packet SP including the information addressed to its own wireless communication device 91 from the packet path determination unit 31, the serial packet processing unit 33 determines the generated serial packet SP as a packet path. To the unit 31.

  At this time, the serial packet processing unit 33 performs a continuous transmission process in which the same serial packet SP is repeatedly output to the packet path determination unit 31 until new serial information is received from the terminal CT via the wired communication unit 12.

(CP reception status setting process)
The basic role of the control packet CP is to collect communication quality information measured at each radio station, collect contact information sampled at each radio station, carry command information to each radio station, and from each radio station Such as transporting responses to command information.

  In any of the roles of the control packet CP described above, if each wireless station updates the contact information and command information stored in the control packet CP each time the control packet CP arrives, data is lost. there is a possibility.

  Referring to FIG. 8 again, for example, the following situation is assumed when control packet CP is transmitted as indicated by a thick arrow. That is, in the wireless communication between the master station 101 with the station number 9 and the slave station 202 with the station number 7, the control packets CP0 and CP1 do not reach the slave station 202 with the station number 7 due to the influence of interference waves. Then, it is assumed that the influence of the interference wave disappears and the control packet CP2 transmitted from the main station 101 returns to the main station 101 along the communication path indicated by the thick arrow.

  In this situation, the communication path of the control packets CP0 and CP1 starts from the main station 101 of the station number 9 and then the station numbers 2, 3, 4, 1, 4, 3, 2, 9, 6, 5, 6, 9 It becomes a communication path that goes through in the order of wireless stations.

  For example, when the relay station 151 with the station number 2 receives the control packet CP0 from the main station 101, the relay station 151 stores about 20 pieces of accumulated contact information PI0 in the control packet CP0. Thereafter, when the relay station 151 with the station number 2 receives the control packet CP1 or CP2 from the main station 101, the contact information PI1 or PI2 newly accumulated instead of the contact information PI0 is stored in the control packet CP1 or CP2, respectively. Sometimes the following problems arise.

  That is, since the master station 101 and the slave stations 202 with station numbers 7 and 8 cannot receive the control packets CP0 and CP1, they cannot receive the contact information PI0 and PI1. Therefore, the contact information PI0 and PI1 are lost in the wireless communication between the master station 101 and the slave station 202 having the station number 7 in the middle of traveling around each wireless station.

  That is, if each wireless station updates the contact information and command information stored in the control packet CP every time it receives the control packet CP, the data is lost when a communication failure occurs in the communication path of the control packet CP. There is a possibility that.

  Further, the slave station 202 with the station numbers 7 and 8 can receive the control packet CP for the first time in the slot RS2. More specifically, the slave station 202 of the station numbers 7 and 8 cannot receive the control packets CP0 and CP1 in the slots RS0 and RS1, respectively, but can receive the control packet CP2 for the first time in the slot RS2, Information or the like is stored in the control packet CP2.

  FIG. 21 is a diagram illustrating a configuration of the control packet processing unit in the packet processing unit according to the first embodiment of the present invention.

  Referring to FIG. 21, control packet processing unit 34 includes a CP reception state setting unit 41, a transfer processing unit 42, a retransmission processing unit 43, and a recovery notification packet processing unit 44.

  The CP reception state setting unit 41 in the control packet processing unit 34 sets a CP reception state for optimizing the timing at which the communication quality information, contact information, and command information to be stored in the control packet CP are updated.

  More specifically, when receiving the control packet CP together with the station number of the transmission source radio station from the packet path determination unit 31, the CP reception state setting unit 41 sets its own CP reception state.

  FIG. 22 is a diagram illustrating an example of a CP reception state transition route set in the control packet processing unit according to the first embodiment of the present invention.

  FIG. 23 is a diagram showing an example of a CP reception state transition table used in the control packet processing unit according to the first embodiment of the present invention.

  Referring to FIGS. 22 and 23, CP reception state setting unit 41 recognizes the number of transmissions of control packet CP based on, for example, the value stored in the retransmission number field in control packet CP. In addition, the CP reception state setting unit 41 obtains a comparison result between the serial number of the previous control packet CP and the serial number of the current control packet CP based on the serial number stored in the serial number field, for example.

  Whether the CP reception state setting unit 41 has received a control packet CP having the same serial number from the wireless communication device 91 having the same station number based on the serial number and the station number of the transmission source wireless station of the control packet CP, for example. An arrival confirmation process is performed to confirm whether or not.

  The CP reception state setting unit 41 sets the CP reception state by fitting the number of transmissions of the control packet CP, the serial number comparison result, and the arrival confirmation result to the CP reception state transition table, for example.

  Specifically, the CP reception state setting unit 41 changes the CP reception state to S0 when the current CP reception state is S0, S1, or S2 and the transmission count of the control packet CP is “first”. Transition.

  Further, when the current CP reception state is S0, S1, or S2, the CP reception state setting unit 41 performs the following processing when the number of transmissions of the control packet CP is “second”. That is, the CP reception state setting unit 41 transitions the CP reception state to S1 when the serial number comparison result is “match” and the arrival confirmation result is “YES”. The CP reception state setting unit 41 receives the CP reception when the serial number comparison result is “match” and the arrival confirmation result is “NO”, or when the serial number comparison result is “mismatch”. The state is changed to S0.

  In addition, when the current CP reception state is S0, S1, or S2, the CP reception state setting unit 41 performs the following processing when the number of transmissions of the control packet CP is “after the third”. That is, the CP reception state setting unit 41 transitions the CP reception state to S2 when the serial number comparison result is “match” and the arrival confirmation result is “YES”. The CP reception state setting unit 41 receives the CP reception when the serial number comparison result is “match” and the arrival confirmation result is “NO”, or when the serial number comparison result is “mismatch”. The state is changed to S0.

  For example, when the CP reception state after the transition is S0, the CP reception state setting unit 41 outputs the CP reception state after the transition, the station number of the transmission source radio station, and the control packet CP to the transfer processing unit 42. For example, when the CP reception state after the transition is S1 or S2, the CP reception state setting unit 41 outputs the CP reception state after the transition, the station number of the transmission source radio station, and the control packet CP to the retransmission processing unit 43. To do.

(Control packet transfer processing)
When the transfer processing unit 42 receives, for example, the CP reception state after the transition, the station number of the transmission source radio station, and the control packet CP from the CP reception state setting unit 41, the transfer processing unit 42 stores it in “RSSI / NOISE” in the received control packet CP. In addition, the RSSI value and noise level of the receiving section are acquired.

  Then, for example, the transfer processing unit 42 stores the reception section specified by the station number of the transmission source wireless station and the station number of its own wireless communication device 91, and the acquired RSSI value and noise level in the wireless state field in the control packet CP. To do.

  In addition, for example, the transfer processing unit 42 includes the information addressed to its own wireless communication device 91 in the control packet CP received from the CP reception state setting unit 41, and the information included in the received control packet CP is the previous time. If it is different from the information included in the received control packet CP, the information addressed to the own wireless communication device 91 received this time is transmitted to the terminal connected to the own wireless communication device 91.

  Specifically, for example, when the contact out setting is ON, the transfer processing unit 42 performs the following processing when the serial number of the control packet CP received this time is different from the serial number of the control packet CP received last time. I do.

  That is, the transfer processing unit 42 acquires the amount and status of contact information from the contact information field in the control packet CP, for example. Then, for example, based on the amount and status of the acquired contact information, the transfer processing unit 42 acquires contact information with a normal status from the contact information field. At this time, for example, the transfer processing unit 42 may acquire contact information of all wireless stations in the wireless communication system 301 or may acquire contact information of some wireless stations.

  Then, for example, the transfer processing unit 42 outputs the acquired contact information to the contact information processing unit 16. The contact information processing unit 16 generates a contact signal from the contact information received from the transfer processing unit 42 and transmits the generated contact signal to a terminal connected to its own wireless communication device 91.

  For example, when the contact-in setting is ON, the transfer processing unit 42 acquires contact information from the contact information first buffer 18 or the contact information second buffer based on the storage location information received from the contact information processing unit 16. In addition, the transshipment information is output to the contact information processing unit 16. Then, for example, the transfer processing unit 42 clears the information related to the contact information stored in the previous cycle from the contact information field, and then stores the contact information acquired this time and the amount of the contact information in the contact information field.

  For example, when command information addressed to the wireless communication device 91 is stored in the control message field, the transfer processing unit 42 acquires the command information and outputs the acquired command information to the external command processing unit 15. To do. At this time, for example, the transfer processing unit 42 turns on a bit indicating that the own wireless communication device 91 has acquired the command information in the control message reception bit field of the control packet CP.

  Then, the transfer processing unit 42 outputs the CP reception state indicating S0 and the control packet CP to the packet path determination unit 31, and associates a copy of the control packet CP with the station number of the transmission source radio station in the storage unit 17. save.

(Retransmission processing of control packet)
For example, when receiving the CP reception state after the transition, the station number of the transmission source radio station, and the control packet CP from the CP reception state setting unit 41, the retransmission processing unit 43 performs the following processing. That is, for example, when the information included in the control packet CP received from the CP reception state setting unit 41 is the same as the information included in the control packet CP received last time, the retransmission processing unit 43 receives the previous control packet CP. The control packet CP transmitted to the other wireless communication device 91 is retransmitted to the other wireless communication device 91.

  For example, the retransmission processing unit 43 includes the information addressed to its own wireless communication device 91 in the control packet CP received from the CP reception state setting unit 41, and the information included in the received control packet CP is the previous time. If it is the same as the information included in the received control packet CP, the information addressed to the own wireless communication device 91 received this time is discarded.

  Specifically, for example, the retransmission processing unit 43 transmits the control packet CP having the same serial number as the serial number of the control packet CP received this time and stored in the storage unit 17 by the transfer processing unit 42. A control packet CP associated with the station number of the original wireless station is acquired.

  Then, for example, retransmission processing unit 43 copies the values stored in the identifier field and retransmission number field in control packet CP received this time to the identifier field and retransmission number field in acquired control packet CP. For example, the retransmission processing unit 43 outputs the processed control packet CP to the packet route determining unit 31 together with the CP reception state indicating S1 or S2.

  For example, even when the contact out setting is ON, the retransmission processing unit 43 does not acquire contact information from the control packet CP.

  Thereby, since the same contact information is not duplicated and output to the contact information processing unit 16, the contact information processing unit 16 can avoid repeatedly generating the same contact signal. That is, the contact information processing unit 16 can correctly generate the contact signal.

  Also, the retransmission processing unit 43 does not acquire the command information even when, for example, command information addressed to its own wireless communication device 91 is stored in the control message field. Thereby, it is possible to avoid that the external command processing unit 15 performs the operation change processing redundantly based on the same external command.

  For example, even when the contact-in setting is ON, the retransmission processing unit 43 does not clear and store information related to contact information for the contact information field of the control packet CP.

  As a result, in the wireless communication system 301, the same contact information can be stored in any of the control packets CP that circulate in the same cycle, so that the contact information can be prevented from being duplicated and lost.

[Communication packet route determination and transmission process 2]
FIG. 24 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 24, packet path determination unit 31 in each radio station returns to master station 101 via all relay stations 151 and slave stations 202 after control packet CP is transmitted from master station 101, for example. Thus, the transmission destination station number is set so that the number of wireless stations that pass through is minimized.

  Specifically, in the network configuration shown in FIG. 24, the packet route determination unit 31 in each wireless station, for example, from the main station 101 of the station number 9 to the station numbers 6, 5, 6, as indicated by the thick line arrows. The transmission destination station number is set so as to return to the main station 101 of station number 9 via the radio stations of stations 7 and 6, or the stations of station numbers 6, 7, 6, 5 and 6.

  Note that the packet route determination unit 31 in each wireless station may set the transmission destination station number so that the number of wireless stations that pass through is not minimized, for example. Specifically, the packet path determination unit 31 in each radio station, for example, the control packet CP is a radio station from the main station 101 with the station number 9 to the station numbers 6, 5, 6, 9, 6, 7, 6 or the station number 9 The transmission destination station number may be set so as to return from the main station 101 to the main station 101 of the station number 9 via the radio stations of the station numbers 6, 7, 6, 9, 6, 5, 6 in this order.

  For example, when receiving the CP reception state, the station number of the transmission source radio station, and the control packet CP from the transfer processing unit 42 and the retransmission processing unit 43, the packet path determination unit 31 performs the following processing.

  That is, for example, based on the value stored in the serial number field in the received control packet CP, the packet path determination unit 31 acquires the station number of the transmission source radio station stored in the storage unit 17 in association with the value. .

  Then, the packet path determination unit 31 sets the transmission destination station number based on the acquired station number of the transmission source radio station, the value stored in the transmission destination field in the control packet CP, and the entry table.

  When the received CP reception state indicates S0 or S1, the packet path determination unit 31 outputs the control packet CP together with the set transmission destination station number to the wireless communication unit 11. For example, when the received CP reception state indicates S2, the packet path determination unit 31 checks the count value of the counter corresponding to the transmission destination station number in the transmission failure number counter unit 39. For example, when the confirmed count value is 1 or less, the packet route determination unit 31 outputs the control packet CP together with the transmission destination station number to the wireless communication unit 11.

(Control packet loopback processing when slave station fails)
For example, when the received CP reception state indicates S2, the packet path determination unit 31 performs the following processing when the check result of the counter value corresponding to the transmission destination station number is 2 or more.

  That is, for example, the packet path determination unit 31 is connected to the lower station that is the relay station 151 or the slave station 202 connected to the wireless communication device 91 on the downstream side from the master station 101 to the relay station 151 or the slave station 202. Even if the control packet CP is transmitted a predetermined number of times, specifically twice, it is recognized that ACK as a response to the control packet CP is not returned from the lower station to the own station.

  Then, for example, the packet route determination unit 31 generates a rewrite entry table by rewriting the entry table stored in the storage unit 17 as follows, and stores the generated rewrite entry table in the storage unit 17.

  That is, for example, the packet path determination unit 31 excludes the lower station from the transmission destination of the control packet CP and is connected to the wireless communication device 91 on the upstream side from the lower station to the main station 101. A rewrite entry table is generated that is rewritten so as to transmit the control packet CP to the upper station that is the main station 101 or the relay station 151, or to another lower station. In other words, the packet path determination unit 31 is, for example, the main station 101 connected to its own wireless communication device 91 or a higher station that is the relay station 151 connected to its own wireless communication device 91 on the main station 101 side, or A rewrite entry table rewritten to transmit the control packet CP to other lower stations is generated.

  Specifically, for example, in the network configuration shown in FIG. 24, when the packet route determination unit 31 in each wireless station sets the transmission destination station number so that the control packet CP passes through the communication route indicated by the thick arrow, Assume the situation. That is, a situation is assumed in which a communication failure occurs between the relay station 151 of the station number 6 and the slave station 202 of the station number 5 due to a failure in the slave station 202 of the station number 5 or power-off.

  In this situation, for example, the main station 101 transmits the control packet CP0 to the relay station 151 with the station number 6 in the slot RS0. Each processing unit in the relay station 151 with the station number 6 performs the following processing.

  That is, for example, the packet route determination unit 31 outputs the control packet CP0 received from the main station 101 to the control packet processing unit 34, and then transmits the CP reception state indicating S0 and the processed control packet CP0 from the transfer processing unit 42. When received, the received control packet CP0 is transferred to the slave station 202 of the station number 5 based on the entry table. After the transfer, for example, the packet path determination unit 31 cannot receive an ACK from the slave station 202 with the station number 5, and therefore increments the count value of the station number 5 in the transmission failure number counter unit 39 to 1.

  For example, since the main station 101 could not receive the control packet CP0 to be circulated by the timing when the slot RS0 expires, the main station 101 retransmits the control packet CP1 to the relay station 151 of the station number 6 in the slot RS1. .

  The packet path determination unit 31 in the relay station 151 with the station number 6 outputs, for example, the control packet CP1 received from the main station 101 to the control packet processing unit 34, and then displays the CP reception state indicating S1 and the processed control packet CP1. When received from the retransmission processing unit 43, the received control packet CP1 is retransmitted to the slave station 202 of the station number 5 based on the entry table. After the retransmission, for example, the packet path determination unit 31 cannot receive an ACK from the slave station 202 with the station number 5, and therefore increments the count value of the station number 5 in the transmission failure number counter unit 39 to 2.

  For example, since the main station 101 could not receive the control packet CP1 to be circulated by the timing when the slot RS1 expires, the main station 101 retransmits the control packet CP2 to the relay station 151 of the station number 6 in the slot RS2. .

  The packet path determination unit 31 in the relay station 151 with the station number 6 outputs, for example, the control packet CP2 received from the main station 101 to the control packet processing unit 34, and then displays the CP reception state indicating S2 and the control packet CP2 after processing. Received from the retransmission processing unit 43.

  The packet path determination unit 31 recognizes that the transmission destination station number is 5 based on the entry table, and confirms the count value of the station number 5 in the transmission failure number counter unit 39. When the packet path determination unit 31 confirms that the count value is 2, it considers that the slave station 202 with the station number 5 cannot communicate, and assumes that the control packet CP2 has returned from the slave station 202 with the station number 5. Continue.

  Specifically, for example, in the entry table, the packet path determination unit 31 excludes the slave station 202 with the station number 5 from the transmission destination of the control packet CP, and then receives the control packet CP received from the master station 101 with the slave station with the station number 7 next. A rewrite entry table rewritten so as to be transmitted to 202 is generated. Here, the slave station 202 with the station number 7 is a radio station to be transmitted when the control packet CP is returned from the slave station 202 with the station number 5. For example, the packet path determination unit 31 stores the generated rewrite entry table in the storage unit 17.

  Based on the rewrite entry table, the packet route determination unit 31 retransmits the control packet CP2 received from the retransmission processing unit 43 to the slave station 202 with the station number 7. At this time, for example, in the contact information field of the control packet CP2, the packet route determination unit 31 sets the status of the content included in the area where the slave station 202 with the station number 5 is to store contact information as an error.

  As a result, the contact information included in the area where the slave station 202 with the station number 5 should store the contact information is invalidated, so that inappropriate contact information can be prevented from being transmitted to the terminal.

  Note that the packet path determination unit 31 determines that the control packet CP is transmitted to the lower station a predetermined number of times, and the control packet CP is not returned from the lower station to the own station. Although the configuration is such that the subordinate station is excluded from the transmission destination of the CP, the present invention is not limited to this.

  For example, when the packet path determination unit 31 recognizes that the control packet CP does not return from the lower station to the own station even if the control packet CP is transmitted to the lower station a predetermined number of times, the packet path determination unit 31 The structure which excludes the said low order station may be sufficient.

  Specifically, for example, in the network configuration shown in FIG. 8, a situation is assumed in which a communication failure occurs between the master station 101 and the slave station 202 of the station number 7 due to a failure in the slave station 202 of the station number 7 or power-off. . For example, even if the packet route determination unit 31 in the master station 101 transmits the control packet CP twice to the slave station 202 of the station number 7 which is a lower station, the control packet CP does not return from the slave station 202 of the station number 7 to the own station. If recognized, the slave station 202 with the station number 7 is excluded from the transmission destination of the control packet CP.

  In other words, the main station 101, in the case of a failure in a subordinate station directly connected to itself, has a subordinate that has failed from the transmission destination of the control packet CP based on the presence or absence of the control packet CP from the subordinate station to the own station Stations can be excluded.

  On the other hand, the main station 101 has not failed from the transmission destination of the control packet CP based on the presence / absence of the control packet CP from the lower station to the own station with respect to the failure in the lower station not directly connected to itself. Subordinate stations may be excluded. For this reason, a configuration in which the lower station is excluded from the transmission destination of the control packet CP based on the presence or absence of ACK from the lower station to the own station is preferable.

(Control packet loopback processing when relay station fails)
FIG. 25 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention.

  In the network configuration shown in FIG. 25, when the packet path determination unit 31 in each radio station sets the transmission destination station number so that the control packet CP passes through the communication path indicated by the thick arrow, the following situation is assumed. That is, a situation is assumed in which a communication failure occurs between the relay station 151 with the station number 6 and the relay station 151 with the station number 5 due to a failure in the relay station 151 with the station number 5 or power-off.

  In this situation, for example, main station 101 transmits and retransmits control packets CP0 and CP1 to relay station 151 of station number 6 in slots RS0 and RS1, respectively.

  In response to the control packets CP0 and CP1 received from the main station 101, the relay station 151 with the station number 6 transfers and retransmits the processed control packets CP0 and CP1 to the relay station 151 with the station number 5, respectively. ACK cannot be received from the relay station 151 with the station number 5. For this reason, in the transmission failure frequency counter unit 39 in the relay station 151 of the station number 6, the counter of the station number 5 is incremented twice and the count value becomes 2.

  For example, since the main station 101 could not receive the control packet CP1 to be circulated by the timing when the slot RS1 expires, the main station 101 retransmits the control packet CP2 to the relay station 151 of the station number 6 in the slot RS2. .

  As a result of receiving the control packet CP2 from the main station 101, the relay station 151 with the station number 6 performs the following processing because the CP reception state has shifted to S2. That is, the relay station 151 with the station number 6 recognizes that the transmission destination station number is 5 based on the entry table, and confirms the count value of the station number 5 in the transmission failure number counter unit 39. For example, when the relay station 151 with the station number 6 confirms that the count value is 2, the relay station 151 with the station number 5 considers that communication is impossible, and generates a rewrite entry table.

  More specifically, for example, the relay station 151 with the station number 6 excludes the relay station 151 with the station number 5 from the transmission destination of the control packet CP in the entry table, and then receives the control packet CP received from the main station 101 with the station number 7 next. The rewrite entry table rewritten so as to be transmitted to the slave station 202 is generated. Here, the slave station 202 with the station number 7 is a radio station to be transmitted when the control packet CP is returned from the relay station 151 with the station number 5.

  Then, the relay station 151 with the station number 6 retransmits the processed control packet CP2 to the slave station 202 with the station number 7 based on the generated rewrite entry table. At this time, for example, the relay station 151 of the station number 6 makes an error in each status regarding the contents included in the area in which the radio stations of the station numbers 1 to 5 store contact information in the contact information field of the control packet CP2. Set.

  As a result, the contact information included in each area where the wireless stations with the station numbers 1 to 5 should store contact information is invalidated, so that inappropriate contact information is prevented from being transmitted to the terminal. it can.

  For example, even when the above-described loopback processing is performed in the network configurations shown in FIGS. 24 and 25, if the failure or power-off of the wireless station with the station number 5 is resolved, the relay station 151 with the station number 6 and the station number 5 Communication failure with the radio station is recovered.

  The relay station 151 with the station number 6 sets the transmission destination station numbers of the control packets CP0 and CP1 to the wireless station with the station number 5 based on the entry table regardless of the count value of the transmission destination station number in the transmission failure number counter unit 39. .

  Thereby, the radio station with the station number 5 or the radio stations with the station numbers 1 to 5 can receive the control packet CP after recovery from the communication failure between the relay station 151 with the station number 6 and the radio station with the station number 5.

(Control packet loopback processing when a wireless station that communicates directly with the main station fails)
FIG. 26 is a diagram illustrating an example of a network configuration of each wireless station in the wireless communication system according to the first embodiment of the present invention.

  In the network configuration shown in FIG. 26, when the packet path determination unit 31 in each radio station sets the transmission destination station number so that the control packet CP passes through the communication path indicated by the thick arrow, the following situation is assumed. In other words, a situation is assumed in which a communication failure occurs between the master station 101 and the slave station 202 of the station number 2 due to a failure in the slave station 202 of the station number 2 or power-off.

  In this situation, for example, the master station 101 transmits a control packet CP0 to the slave station 202 with the station number 1 in the slot RS0. The slave station 202 with the station number 1 transfers the processed control packet CP0 to the master station 101 in response to the control packet CP0 received from the master station 101.

  In response to the control packet CP0 received from the slave station 202 with the station number 1, the master station 101 transfers the processed control packet CP0 to the slave station 202 with the station number 2, but may receive an ACK from the slave station 202 with the station number 2. Can not. For this reason, the count value of the station number 2 in the transmission failure counter 39 in the main station 101 is incremented to 1.

  For example, since the master station 101 could not receive the control packet CP0 to be circulated by the timing when the slot RS0 expires, the master station 101 retransmits the control packet CP1 to the slave station 202 of the station number 1 in the slot RS1. In response to the control packet CP1 received from the master station 101, the slave station 202 with the station number 1 retransmits the processed control packet CP1 to the master station 101.

  The master station 101 retransmits the processed control packet CP1 to the slave station 202 of the station number 2 in response to the control packet CP1 received from the slave station 202 of the station number 1, but may receive an ACK from the slave station 202 of the station number 2. Can not. For this reason, the count value of the station number 2 in the transmission failure counter 39 in the main station 101 is incremented to 2.

  For example, since the master station 101 could not receive the control packet CP1 to be circulated by the timing when the slot RS1 expires, the master station 101 retransmits the control packet CP2 to the slave station 202 of the station number 1 in the slot RS2. The slave station 202 with the station number 1 retransmits the processed control packet CP2 to the master station 101 in response to the control packet CP2 received from the master station 101.

  As a result of receiving the control packet CP2 from the slave station 202 of the station number 1, the master station 101 performs the following processing since the CP reception state has shifted to S2. That is, the main station 101 recognizes that the transmission destination station number is 2 based on the entry table, and confirms the count value of the station number 2 in the transmission failure number counter unit 39. For example, when the master station 101 confirms that the count value is 2, the slave station 202 with the station number 2 is considered to be unable to communicate and generates a rewrite entry table.

  Specifically, the master station 101, for example, excludes the slave station 202 with the station number 2 from the transmission destination of the control packet CP in the entry table, and then sends the control packet CP received from the slave station 202 with the station number 1 to the slave station with the station number 3 next. A rewrite entry table rewritten so as to be transmitted to 202 is generated. Here, the slave station 202 with the station number 3 is a radio station to be transmitted when the control packet CP is returned from the slave station 202 with the station number 2.

  Then, the master station 101 retransmits the processed control packet CP2 to the slave station 202 of the station number 3 based on the generated rewrite entry table. At this time, for example, in the contact information field of the control packet CP2, the master station 101 sets the status of the content included in the area in which the slave station 202 with the station number 2 is to store contact information as an error.

  As a result, the contact information included in the area where the slave station 202 of the station number 2 should store the contact information is invalidated, so that inappropriate contact information can be prevented from being transmitted to the terminal.

  For example, in the network configuration shown in FIG. 26, even when the above-described loopback process is performed, if the failure or power-off in the slave station 202 with station number 2 is resolved, the master station 101 and the slave station 202 with station number 2 are not connected. The communication failure in is recovered.

  For example, when the master station 101 receives the control packets CP0 and CP1 from the slave station 202 with the station number 1 in each of the slots RS0 and RS1 of the next cycle, regardless of the count value of the transmission destination station number in the transmission failure number counter unit 39, Based on the entry table, the transmission destinations of the control packets CP0 and CP1 are set to the slave station 202 of the station number 2, respectively.

  Thereby, the slave station 202 with the station number 2 can receive the control packet CP from the master station 101 after recovery from the communication failure between the master station 101 and itself.

(Control packet loopback processing when multiple radio stations fail)
For example, in the network configuration shown in FIG. 26, when the packet path determination unit 31 in each radio station sets the transmission destination station number so that the control packet CP passes through the communication path indicated by the thick line arrow, the following situation is assumed. That is, a situation is assumed in which a communication failure occurs between the master station 101 and the slave station 202 of the station number 2 and the slave station 202 of the station number 3 due to a failure in the slave stations 202 of the station numbers 2 and 3 or power-off.

  In this situation, for example, the master station 101 transmits and retransmits the control packets CP0 and CP1 to the slave station 202 of the station number 1 in the slots RS0 and RS1, respectively. Since processing of master station 101 and slave station 202 of station number 1 for control packets CP0 and CP1 is similar to the processing described above, detailed description will not be repeated.

  For example, since the master station 101 could not receive the control packet CP1 to be circulated by the timing when the slot RS1 expires, the master station 101 retransmits the control packet CP2 to the slave station 202 of the station number 1 in the slot RS2. The slave station 202 with the station number 1 retransmits the processed control packet CP2 to the master station 101 in response to the control packet CP2 received from the master station 101.

  As a result of receiving the control packet CP2 from the slave station 202 of the station number 1, the master station 101 performs the following processing since the CP reception state has shifted to S2. That is, the main station 101 recognizes that the transmission destination station number is 2 based on the entry table, and confirms the count value of the station number 2 in the transmission failure number counter unit 39. For example, when the main station 101 confirms that the count value is 2, it generates a rewrite entry table.

  Specifically, the master station 101, for example, excludes the slave station 202 with the station number 2 from the transmission destination of the control packet CP in the entry table, and then sends the control packet CP received from the slave station 202 with the station number 1 to the slave station with the station number 3 next. A rewrite entry table rewritten so as to be transmitted to 202 is generated. Here, the slave station 202 with the station number 3 is a radio station to be transmitted when the control packet CP is returned from the slave station 202 with the station number 2.

  Then, the master station 101 sets the status of the contents included in the area where the slave station 202 of the station number 2 is to store the contact information in the contact information field of the control packet CP2 after processing, and then generates the rewrite entry generated. Based on the table, the control packet CP2 is transferred to the slave station 202 of the station number 3. After the transfer, the master station 101 cannot receive the ACK from the slave station 202 with the station number 3. For this reason, the count value of the station number 3 in the transmission failure number counter unit 39 in the main station 101 is incremented to 1.

  For example, since the master station 101 could not receive the control packet CP2 to be circulated by the timing when the slot RS2 expires, the master station 101 retransmits the control packet CP3 to the slave station 202 of the station number 1 in the slot RS3. In response to the control packet CP3 received from the master station 101, the slave station 202 with the station number 1 retransmits the processed control packet CP3 to the master station 101.

  As a result of receiving the control packet CP3 from the slave station 202 of the station number 1, the master station 101 performs the following processing because the CP reception state has shifted to S2. That is, the main station 101 recognizes that the transmission destination station number is 3 based on the rewrite entry table, and confirms the count value of the station number 3 in the transmission failure number counter unit 39.

  When the master station 101 confirms that the count value is 1, it retransmits the control packet CP3 to the slave station 202 with the station number 3, but cannot receive the ACK from the slave station 202 with the station number 3. For this reason, the count value of station number 3 in the transmission failure counter 39 in the main station 101 is incremented to 2.

  For example, since the master station 101 could not receive the control packet CP3 to be circulated by the timing when the slot RS3 expires, the master station 101 retransmits the control packet CP4 to the slave station 202 of the station number 1 in the slot RS4. The slave station 202 with the station number 1 retransmits the processed control packet CP4 to the master station 101 in response to the control packet CP4 received from the master station 101.

  As a result of receiving the control packet CP4 from the slave station 202 of the station number 1, the master station 101 performs the following processing since the CP reception state has shifted to S2. That is, the main station 101 recognizes that the transmission destination station number is 3 based on the rewrite entry table, and confirms the count value of the station number 3 in the transmission failure number counter unit 39.

  For example, when the main station 101 confirms that the count value is 2, it rewrites the rewrite entry table. Specifically, for example, in the rewrite entry table, the master station 101 excludes the slave station 202 with the station number 3 from the transmission destination of the control packet CP, and then receives the control packet CP received from the slave station 202 with the station number 1 next to the station number 4 The rewrite entry table is rewritten so as to be transmitted to the slave station 202. Here, the slave station 202 with the station number 4 is a radio station to be transmitted when the control packet CP is returned from the slave station 202 with the station number 3.

  Then, the master station 101 retransmits the processed control packet CP4 to the slave station 202 of the station number 4 based on the rewritten entry table. At this time, for example, in the contact information field of the control packet CP4, the master station 101 sets the status of the contents included in the area where the slave stations 202 of the station numbers 2 and 3 are to store contact information as an error.

  For example, when the slave station 202 with the station number 4 is operating normally, the master station 101 receives the control packet CP4 circulated by the timing when the slot RS4 expires from the slave station 202 with the station number 4, and transmits the serial packet SP. To start.

  After the next cycle, the control packets CP0 and CP1 leave the master station 101 with the station number 9 in the slots RS0 and RS1, respectively, and then pass through the slave station 202 and the master station 101 in the order of the station number 1, and then the master station 101 and the station number 2 Is not received by the slave station 202 of the station number 2 due to a communication failure between the slave stations 202 of At this time, the count value of the station number 2 in the transmission failure number counter unit 39 of the main station 101 is incremented twice and becomes 4.

  The control packet CP2 departs from the master station 101 of the station number 9 in the slot RS2 and then passes through the slave station 202 and the master station 101 in the order of the station number 1, and then the station numbers 2 and 3 of the transmission failure counter 39 of the master station 101. Since the count values are 4 and 2, respectively, it is transmitted to the slave station 202 of station number 4. The control packet CP2 is transmitted from the slave station 202 with the station number 4 to the master station 101.

  As described above, the communication paths of the control packets CP0 and CP1 are set based on the entry table regardless of the transmission destination station number, for example, the count value of the station number 2 in the transmission failure frequency counter unit 39 of the main station 101. Therefore, the master station 101 transmits the control packets CP0 and CP1 to the slave station 202 of station number 2 every cycle.

  Thereby, the slave station 202 with the station number 2 can receive the control packet CP0 or CP1 from the master station 101, for example, when it is restored to the normal state.

  On the other hand, the slave station 202 with the station number 3 cannot receive the control packet CP even if the slave station 202 with the station number 2 is restored to the normal state before the slave station 202 is restored to the normal state. More specifically, the control packets CP0 and CP1 are transmitted between the master station 101 and the slave station 202 of the station number 2 after passing through the slave station 202 and the master station 101 in this order after leaving the master station 101 of the station number 9. The slave station 202 with the station number 3 cannot be reached due to a failure. In addition, since the count value of the station number 3 in the transmission failure counter 39 of the master station 101 is 2, the control packets CP2 to CP4 depart from the master station 101 of the station number 9 and the slave station 202 and the master station of the station number 1 After passing through the order of 101, the data is transmitted to the slave station 202 of station number 4.

(Recovery notification packet)
Referring again to FIG. 21, the recovery notification packet processing unit 44 in the control packet processing unit 34 is, for example, a master station 101 or a relay station 151 connected to the upstream side with respect to its own wireless communication device 91. When the control packet CP is not received for a predetermined time from the station, a recovery notification process for transmitting a recovery notification packet for notifying that the own wireless communication device 91 has recovered to the upper station is performed.

  Specifically, for example, the recovery notification packet processing unit 44 in the slave station 202 of the station number 3 shown in FIG. 26 monitors the control packet CP from the packet path determination unit 31, for example. For example, when the next notification packet CP cannot be received for 6 seconds after receiving a certain control packet CP, the recovery notification packet processing unit 44 generates a recovery notification packet that is a kind of the control packet CP. The recovery notification packet does not include a “message payload”.

  For example, the recovery notification packet processing unit 44 stores 0b0100, 0x00, 0x09, and 0x03 in the identifier field, the used CH field, the transmission destination field, and the transmission source field in the recovery notification packet, respectively.

  Then, the recovery notification packet processing unit 44 outputs the generated recovery notification packet to the packet route determination unit 31, for example. For example, when receiving the recovery notification packet from the recovery notification packet processing unit 44, the packet path determination unit 31 transmits the received recovery notification packet to the upper station, that is, the main station 101 of the station number 9 via the wireless communication unit 11.

  For example, when the recovery notification packet processing unit 44 cannot receive the control packet CP for 6 seconds after transmitting the recovery notification packet, the recovery notification packet processing unit 44 sends the next recovery notification packet to the main station 101 of the station number 9 via the packet path determination unit 31. Send.

  For example, the recovery notification packet processing unit 44 may transmit the generated recovery notification packet irregularly or only once.

  Further, the recovery notification packet processing unit 44 receives the recovery notification packet from the lower station and adds the lower station to the transmission destination of the control packet CP when the lower station is excluded from the transmission destination of the control packet CP. Perform recovery processing.

  Specifically, for example, when the packet path determination unit 31 in the main station 101 of the station number 9 shown in FIG. 26 receives the recovery notification packet via the wireless communication unit 11, for example, the received recovery notification packet is processed into the recovery notification packet processing. To the unit 44. For example, when the recovery notification packet processing unit 44 receives the recovery notification packet from the packet route determination unit 31, the recovery notification packet processing unit 44 acquires the station number 3 that is the station number of the transmission source wireless station from the transmission source field in the received recovery notification packet.

  Then, the recovery notification packet processing unit 44 confirms whether or not the wireless station with the station number 3 has been excluded from the transmission destination of the control packet CP based on the acquired station number 3 and the rewrite entry table.

  For example, when the wireless station with the station number 3 is excluded from the transmission destination of the control packet CP, the recovery notification packet processing unit 44 rewrites the rewrite entry table. At this time, for example, the recovery notification packet processing unit 44 rewrites the rewrite entry table so that the slave station 202 with the station number 3 is added to the transmission destination of the control packet CP in the rewrite entry table.

  Then, for example, the recovery notification packet processing unit 44 resets the count value of the counter corresponding to the station number 3 which is the station number of the transmission source radio station in the transmission failure number counter unit 39 to zero.

  After the recovery notification process in the slave station 202 with the station number 3 and the recovery process in the master station 101 are performed, the control packets CP0 and CP1 leave the master station 101 with the station number 9 in the slots RS0 and RS1, respectively. After passing through the slave station 202 and the master station 101 in this order, the slave station 202 of the station number 2 is not received due to a communication failure between the master station 101 and the slave station 202 of the station number 2. Therefore, the slave station 202 with the station number 3 cannot receive the control packets CP0 and CP1.

  On the other hand, the rewrite entry table is rewritten to add the slave station 202 with the station number 3 to the transmission destination of the control packet CP, and the count value of the station number 3 in the transmission failure number counter unit 39 of the master station 101 is zero. The CP 2 is transmitted to the slave station 202 of the station number 3 after leaving the slave station 202 of the station number 1 and the master station 101 in this order after leaving the master station 101 of the station number 9 in the slot RS2.

  As described above, the slave station 202 with the station number 3 restored to the normal state transmits the restoration notification packet to the upper station, so that the slave station 202 with the station number 3 enters the normal state before the slave station 202 with the station number 2 is restored to the normal state. Even after recovery, the control packet CP can be received.

  The packet path determination unit 31 in the relay station 151 and the slave station 202 does not return the control packet CP from the lower station to the own station when the transmission of the control packet CP to the lower station fails twice in succession. Although it is the structure which recognizes, it is not limited to this. The packet path determination unit 31 recognizes that the control packet CP does not return from the lower station to the own station when, for example, transmission of the control packet CP to the lower station fails continuously once or three times or more. It may be.

  In addition, each wireless station other than the main station 101 in the wireless communication system 301 performs a reception-driven operation as described above. On the other hand, the recovery notification packet processing unit 44 transmits the recovery notification packet via the packet route determination unit 31 at its own timing. For this reason, the timing at which a certain radio station transmits a recovery notification packet may overlap with the timing at which another radio station transmits a communication packet. In this case, there is a high possibility of communication failure due to interference.

  On the other hand, the recovery notification packet processing unit 44 generates a recovery notification packet that does not include the “message payload”. Thereby, since the size of the recovery notification packet can be reduced, the transmission time of the recovery notification packet can be shortened.

  Further, the recovery notification packet processing unit 44 transmits the recovery notification packet via the packet route determination unit 31 at a cycle of 6 seconds which is sufficiently longer than the transmission cycle of 200 milliseconds.

  With this configuration, it is possible to reduce the possibility that the timing at which a certain radio station transmits a recovery notification packet and the timing at which another radio station transmits a communication packet overlap, so that a communication failure due to interference occurs. Probability can be reduced.

[Operation]
FIG. 27 is a flowchart defining an operation procedure when the master station, the relay station, and the slave station transmit and receive communication packets in the wireless communication system according to the first embodiment of the present invention. The master station 101, the relay station 151, and the slave station 202 include a computer, and an arithmetic processing unit such as a CPU in the computer reads and executes a program including a part or all of each step of the following flowchart from a memory (not shown). . The program of this apparatus can be installed from the outside. The program of this device is distributed in a state stored in a recording medium.

  Referring to FIG. 27, first, main station 101 allocates each slot in the transmission cycle to transmission of control packet CP and transmission of serial packet SP, for example, before the start of a certain transmission cycle, or NOP. Thus, a communication schedule is created (step S102).

  Next, the main station 101 transmits a control packet CP0 to another wireless station according to the created communication schedule (step S104).

  Next, the relay station 151 and the slave station 202 transfer the control packet CP0 in response to receiving the control packet CP0 from another wireless station (step S106).

  Next, when the main station 101 receives the control packet CP0 that circulates each radio station in the radio communication system 301 in the slot that transmitted the control packet CP0 (YES in step S108), the main station 101 serializes the slot after the slot. The communication schedule is changed so as to be assigned to the transmission of the packet SP (step S118).

  Next, the main station 101 continuously transmits the serial packet SP according to the changed communication schedule (step S120).

  On the other hand, when the main station 101 cannot receive the control packet CP0 that has circulated around each radio station in the radio communication system 301 in the slot that transmitted the control packet CP0 (NO in step S108), the main station 101 follows the communication schedule. Is retransmitted to another radio station (step S110).

  Next, relay station 151 and slave station 202 retransmit control packet CP in response to receiving retransmission control packet CP from another radio station (step S112).

  Next, when the main station 101 receives a retransmission control packet CP that circulates through each wireless station in the wireless communication system 301 in the slot that transmitted the retransmission control packet CP (YES in step S114), the main station 101 follows the slot. The communication schedule is changed so as to allocate the slot for transmission of the serial packet SP (step S118).

  Next, the main station 101 continuously transmits the serial packet SP according to the changed communication schedule (step S120).

  On the other hand, if the main station 101 cannot receive the retransmission control packet CP that has been circulated among the wireless stations in the wireless communication system 301 in the slot that has transmitted the retransmission control packet CP (NO in step S114), the number of retransmissions is increased. It is checked whether or not the maximum number of retransmissions has been reached (step S116).

  Next, when the number of retransmissions has not reached the maximum number of retransmissions (NO in step S116), the main station 101 retransmits the control packet CP to another wireless station according to the communication schedule (step S110).

  On the other hand, when the number of retransmissions reaches the maximum number of retransmissions (YES in step S116), the main station 101 continuously transmits the serial packet SP according to the communication schedule (step S120).

  Next, relay station 151 and slave station 202 transmit serial packet SP in response to receiving serial packet SP from another wireless station (step S122).

  FIG. 28 is a flowchart defining an operation procedure when the relay station and the slave station transmit and receive control packets in the wireless communication system according to the first embodiment of the present invention. FIG. 28 shows details of operations of the relay station 151 and the slave station 202 that have received the control packet CP in steps S106 and S112 of FIG.

  Referring to FIG. 28, first, relay station 151 and slave station 202, that is, the control packet receiving station, waits until receiving control packet CP from another radio station (NO in step S202).

  Next, when the control packet receiving station receives a control packet CP from another wireless station (YES in step S202), it confirms whether or not the control packet CP is the control packet CP received for the first time in this cycle. (Step S204).

  Next, when the control packet CP is the control packet CP received for the first time in the current cycle (YES in step S204), the control packet receiving station extracts the contents stored in the control packet CP, and Rewriting is performed (step S206).

  Next, the control packet receiving station stores the control packet CP whose contents have been rewritten (step S208).

  Next, the control packet receiving station transfers the control packet CP to another radio station (step S212).

  On the other hand, if the control packet CP is not the control packet CP received for the first time in the current cycle (NO in step S204), the control packet receiving station acquires the stored control packet CP (step S210).

  Next, the control packet receiving station retransmits the acquired control packet CP to another wireless station (step S212).

  Next, the control packet receiving station waits until it receives a control packet CP from another wireless station (NO in step S202).

  Note that in the main station 101 according to the first embodiment of the present invention, the packet management unit 32 sends the generated communication packet to another radio station via the packet path determination unit 31 according to the trigger signal and the slot in the communication schedule. Although it is assumed that the transmission is configured, the present invention is not limited to this.

  For example, the packet management unit 32 may be configured to transmit a communication packet to another wireless station via the packet route determination unit 31 at an arbitrary timing. Specifically, for example, the packet management unit 32 transmits the serial packet SP at the timing of receiving the control packet CP that circulates each wireless station of the wireless communication system 301. Then, for example, the packet management unit 32 transmits the next serial packet SP at the timing when the response to the transmitted serial packet SP is received from the slave station 202.

  In the wireless communication system 301 according to the first embodiment of the present invention, the control packet CP is configured to pass through each wireless station in the wireless communication system 301. However, the present invention is not limited to this. The configuration may be such that the control packet CP passes through a predetermined part of the radio stations in the radio communication system 301.

  In addition, the control packet CP that circulates each radio station in the radio communication system 301 according to the first embodiment of the present invention may have a configuration that does not include traffic information. That is, the control packet CP only needs to store communication quality information.

  Further, in the main station 101 according to the first embodiment of the present invention, the packet management unit 32 assigns the serial packet SP to the slot at a timing after the slot allocated for transmission of the control packet CP in the communication schedule of each transmission cycle. However, the present invention is not limited to this. For example, the packet management unit 32 may assign the transmission of the control packet CP to a slot at a timing after the slot assigned to the transmission of the serial packet SP.

  In the radio communication system according to the first embodiment of the present invention, the control packet CP is transmitted from the main station 101 and returns to the main station 101 via each radio station in the radio communication system 301. However, the present invention is not limited to this. The control packet CP may be transmitted from a wireless station other than the main station 101 and returned to the wireless station that transmitted the control packet CP via each wireless station in the wireless communication system 301, for example.

  In the wireless communication system according to the first embodiment of the present invention, the master station 101, the relay station 151, and the slave station 202 are configured to be able to store communication quality information and contact information in the control packet CP. However, the present invention is not limited to this. It suffices that at least one of the master station 101, the relay station 151, and the slave station 202 can store communication quality information and contact information in the control packet CP.

  Further, in the radio communication system according to the first embodiment of the present invention, the master station 101, the relay station 151, and the slave station 202 respond to the reception of the control packet CP or the serial packet SP, respectively, Or although it was set as the structure which transmits serial packet SP, it is not limited to this. For example, the master station 101, the relay station 151, and the slave station 202 may be configured to transmit the serial packet SP or the control packet CP in response to receiving the control packet CP or the serial packet SP, respectively. It may be configured to transmit a communication packet.

  By the way, in the traffic control system, an allowable delay time is defined for traffic information that requires real-time characteristics among traffic information exchanged between traffic facilities.

  For example, when a wireless communication system is applied to a traffic control system, the possibility of communication failure due to interference or the like may be higher than that of wired communication. Further, depending on the communication method used for wireless transmission, the traffic information transmission time may exceed an allowable delay time.

  In such a case, the transmission of traffic information between the traffic facilities fails, or the request for the delay time of the traffic information cannot be satisfied. That is, a technology that can reliably transmit traffic information between traffic facilities is desired.

  In contrast, the wireless communication system according to the first embodiment of the present invention includes a master station 101 that is a wireless station for wirelessly transmitting traffic information, and one or more relay stations 151 and slave stations 202. The master station 101 can transmit communication packets to the relay station 151 and the slave station 202 at predetermined intervals. Relay station 151 and slave station 202 transmit a communication packet or another communication packet in response to receiving the communication packet. The communication packet can store the communication quality information of the wireless station and can pass through each wireless station, and between the corresponding relay station 151 or slave station 202 and the master station 101. Serial packets SP to be transmitted and received are included.

  As described above, since the main station 101 transmits communication packets at predetermined intervals, the transmission opportunities of communication packets can be increased, so that the substantial amount of traffic information to be wirelessly transmitted can be increased. Thereby, since it is possible to increase redundancy in transmission of traffic information, it is possible to reduce the possibility of failure in transmission of traffic information between traffic facilities.

  In addition, since the relay station 151 and the slave station 202 transmit a communication packet or another communication packet in response to receiving the communication packet, the time during which wireless transmission is not performed can be shortened. Efficiency can be increased and punctuality can be ensured. Thereby, the request | requirement of the delay time of traffic information can be satisfy | filled. That is, traffic information can be more reliably transmitted between traffic facilities.

  In addition, since it is not necessary to synchronize time with other radio stations using expensive dedicated hardware, the manufacturing cost of the master station 101, the relay station 151, and the slave station 202 can be reduced.

  Further, the control packet CP passing through the cyclic communication path passing through each wireless station and the serial packet SP passing through the peer-to-peer communication path between the master station 101 and the corresponding relay station 151 or slave station 202 are used. It is possible to diversify communication routes for traffic information in wireless transmission and select an appropriate communication route according to the type of information to be transmitted.

  In addition, since the communication quality information of each wireless station can be quickly transmitted on average, for example, when a communication failure occurs in the wireless communication system 301, the worker can update the latest communication of each wireless station. Quality information can be quickly and collectively acquired. Thereby, the maintenance work of the radio | wireless communications system 301 can be performed efficiently.

  Further, in the wireless communication system according to the first embodiment of the present invention, it is determined that the control packet CP could not be returned to the predetermined wireless station via the relay station 151, the slave station 202, or the master station 101. It will be resent if The serial packet SP having the same content as the previously transmitted serial packet SP is repeatedly transmitted until new information to be included in the serial packet SP is acquired.

  As described above, the control packet CP is retransmitted until the predetermined radio station receives the control packet CP via the relay station 151, the slave station 202, or the master station 101, so that the radio station targeted by the control packet CP is controlled. The possibility that the packet CP can be received can be increased.

  Further, the serial packet SP having the same content as the previously transmitted serial packet SP is repeatedly transmitted until new information to be included in the serial packet SP is acquired, so that the destination wireless station of the serial packet SP can receive the serial packet SP. The possibility that the SP can be received can be increased. That is, redundancy in transmission of the control packet CP and the serial packet SP can be increased.

  In the wireless communication system according to the first embodiment of the present invention, the traffic information is contact information indicating whether or not a vehicle is detected, and information different from the contact information, and is the master station 101, the relay station 151, or the slave station. The serial information which is the information from the terminal connected to 202 is included. Further, contact information can be stored in the control packet CP. Serial information can be stored in the serial packet SP. At least one of the master station 101, the relay station 151, and the slave station 202 can store the communication quality information and the contact information in the control packet CP.

  With such a configuration, the communication quality information and the contact information can be stored in the control packet CP in any wireless station that is the target of the control packet CP, and the stored information is stored in all the wireless targets that are the target of the control packet CP. Since it can be transmitted to a station, the collection and distribution efficiency of communication quality information and contact information can be improved.

  As a result, for example, communication quality information in all the wireless stations that are subject to the control packet CP can be collected, so that the communication state in the wireless communication system 301 can be easily grasped based on the collected communication quality information. it can.

  Further, since the contact information stored in the control packet CP can be easily transmitted to another wireless station in a certain wireless station, for example, the contact signal generated in the ultrasonic sensor 164 connected to the certain wireless station is Other terminals can be used easily. That is, it is possible to easily relax restrictions on terminals that use contact signals generated by the ultrasonic sensor 164.

  Further, since serial information can be transmitted through a peer-to-peer type communication path between the master station 101 and the corresponding relay station 151 or slave station 202, for example, a terminal connected to the master station 101, that is, the central communication device 160 The centralized management of serial information can be performed efficiently.

  In the wireless communication system according to the first embodiment of the present invention, relay station 151 and slave station 202 have the same information contained in received control packet CP as the information contained in previously received control packet CP. In this case, the control packet CP that was received last time and transmitted to another station is retransmitted to the other station. When the relay station 151 and the slave station 202 include the information addressed to the local station in the received control packet CP and the information included in the received control packet CP is different from the information included in the previously received control packet CP, The information addressed to the local station received this time is transmitted to the terminal connected to the local station. The relay station 151 and the slave station 202 include the information addressed to the local station in the received control packet CP, and the information included in the received control packet CP is the same as the information included in the previously received control packet CP. In this case, the information received this time is discarded.

  With this configuration, the information transmitted to the other station for the first time can be transmitted to the other station as it is for the second and subsequent times when it is retransmitted. Therefore, the same information is stored in the wireless station through which the control packet CP is routed. The control packet CP can be received regardless of the number of retransmissions.

  That is, for example, when the control packet CP periodically circulates through each radio station, the contact information stored in the control packet CP can be determined for each transmission cycle, so that each time within the same cycle regardless of the number of retransmissions. It is possible to unify the content of information that circulates through radio stations. Thereby, each said radio station can ensure the temporal continuity of contact information easily.

  In addition, since, for example, command information and a response to the command information can be appropriately exchanged between the master station 101 and the relay station 151 or the slave station 202, the efficiency of maintenance work of the wireless communication system 301 can be improved. Can do.

  In addition, it is possible to avoid the relay station 151 and the slave station 202 from repeatedly transmitting the same information to a terminal connected to the relay station 151 and the slave station 202, so that the processing load can be reduced.

  In addition, since it is possible to avoid the terminal receiving the same information repeatedly, it is possible to avoid useless reception processing at the terminal even if the control packet CP is retransmitted.

  Further, in the wireless communication system according to the first embodiment of the present invention, the relay station 151 and the slave station 202, when the received serial packet SP does not include information addressed to the own station, the serial packet SP received this time To other stations. When the relay station 151 and the slave station 202 include the information addressed to the local station in the received serial packet SP and the information included in the received serial packet SP is different from the information included in the previously received serial packet SP, The information addressed to the local station received this time is transmitted to the terminal connected to the local station. In the relay station 151 and the slave station 202, the received serial packet SP includes information addressed to itself, and the information included in the received serial packet SP is the same as the information included in the previously received serial packet SP. In this case, the information received this time is discarded.

  With such a configuration, the serial packet SP can be appropriately transferred along the peer-to-peer communication path.

  In addition, it is possible to avoid the relay station 151 and the slave station 202 from repeatedly transmitting the same information to a terminal connected to the relay station 151 and the slave station 202, so that the processing load can be reduced.

  Further, since it is possible to avoid the terminal receiving the same information repeatedly, it is possible to avoid useless reception processing at the terminal even if serial packets SP are continuously transmitted.

  In the radio communication system according to the first embodiment of the present invention, the master station 101, the relay station 151, or the slave station 202 is connected to the local station from the master station 101 to the relay station 151 or the slave station 202 in the downlink direction. If the control packet CP or the ACK for the control packet CP is not returned from the lower station to the own station even if the control packet CP is transmitted to the lower station which is the relay station 151 or the slave station 202 connected to the predetermined number of times, the control packet CP The control station CP is transmitted to the upper station that is the relay station 151 connected to the main station 101 connected to the own station or to the own station on the main station 101 side, or another lower station. To do.

  With such a configuration, even when a communication error occurs in a lower station, the control packet CP can be circulated while avoiding the lower station where the communication error has occurred, so information from a wireless station capable of communication is possible As long as it is stored in the control packet CP, it can be transmitted.

  Further, in the wireless communication system according to the first embodiment of the present invention, when the lower station does not receive the control packet CP for a predetermined time from the upper station, the recovery notification for notifying that the own station has recovered Send the packet to the upper station.

  In this way, by the configuration in which the lower station that is excluded from the control packet CP transmits the recovery notification packet to the upper station, the lower station secures a packet transmission opportunity without receiving the communication packet, and the upper station Can recognize the recovery of your station.

  Further, in the wireless communication system according to the first embodiment of the present invention, when the upper station receives the recovery notification packet from the lower station and excludes the lower station from the control packet transmission destination, The lower station is added to the transmission destination of the packet CP.

  With such a configuration, when a lower station where a communication error has occurred is restored, the lower station can be re-incorporated into the target via the control packet CP. Information from the relay station 151 and the slave station 202 connected to the downstream side of the lower station can be stored in the control packet CP and transmitted.

  Further, in the wireless communication system according to the first embodiment of the present invention, the control packet CP is periodically transmitted, and the serial packet SP is transmitted during a period in which the control packet CP is not transmitted in the transmission period of the control packet CP. The control packet CP is transmitted before the serial packet SP in each transmission cycle. The transmission of the serial packet SP is started when a predetermined condition is satisfied.

  Thus, for example, by periodically transmitting a control packet CP that can store contact information acquired periodically, contact information is transmitted at least once in a transmission cycle to each wireless station in the wireless communication system 301. An opportunity to store can be given. Further, the timing for ending the transmission of the serial packet SP can be easily set according to the timing for ending the transmission cycle of the control packet CP.

  In the radio communication system according to the first embodiment of the present invention, the control packet CP is set to the maximum allowable time until it returns to the predetermined radio station via the relay station 151, the slave station 202, or the master station 101. Has been. The length of the transmission cycle is not more than ½ of the maximum allowable time.

  In this way, with the configuration in which the control packet CP is transmitted at least twice within the maximum allowable time, another wireless station acquires the information after a certain wireless station acquires information from a terminal connected to the wireless station. Since the time until acquisition can be kept within the maximum allowable time, for example, the request for the delay time of the contact information can be easily satisfied.

  In the wireless communication system according to the first embodiment of the present invention, the predetermined condition is that the number of retransmissions of the control packet CP has reached a predetermined value, or that the control packet CP has been transmitted to the relay station 151, the slave station 202, or the master station. That is, the mobile station returns to a predetermined wireless station via the station 101.

  As described above, the transmission of the serial packet SP is started under an appropriate condition such as when the control packet CP returns after traveling around the wireless station to be routed or when the redundancy in the transmission of the control packet CP can be ensured to the minimum. can do.

  For example, since the contact information included in the control packet CP is raw data, when the contact information is delayed, the creation timing of information created based on the contact information is also delayed. That is, the delay will spread. On the other hand, since the serial information included in the serial packet SP is, for example, information after processing, the influence of the delay is limited even if the serial information is delayed.

  Therefore, it is possible to suppress the influence of delay from being expanded by the configuration in which the contact information is transmitted with priority over the serial information.

  When the serial communication system SP is not transmitted in the wireless communication system according to the first embodiment of the present invention, the predetermined value is set to the maximum number of times that can be retransmitted in the transmission cycle.

  With such a configuration, redundancy in transmission of the control packet CP can be further increased.

  In the radio communication system according to the first embodiment of the present invention, the control packet CP is transmitted from the master station 101 and then returns to the master station 101 via all the relay stations 151 and slave stations 202. In addition, transmission is performed so that the number of wireless stations that pass through is minimized.

  With such a configuration, communication quality information and contact information are stored in the control packet CP in each wireless station in the wireless communication system 301, and the stored communication quality information and contact information are efficiently transmitted to each wireless station. Therefore, the collection and delivery efficiency of communication quality information and contact information can be improved.

  In addition, since the time required for circulating the control packet CP can be shortened, an increase in the number of slots allocated for cycling the control packet can be suppressed.

  In the radio communication system according to the first embodiment of the present invention, the control packet CP is retransmitted when it is determined that the control packet CP cannot be returned to the predetermined radio station via one or more radio stations. Is done. The retransmission interval of the control packet CP is set to a length corresponding to the number of radio stations that should transmit the control packet CP in the radio communication system 301.

  With such a configuration, it is possible to appropriately set the timing for starting the retransmission process of the control packet CP, so that it is possible to avoid a situation where the control packet CP is kept waiting for the return of the control packet CP.

  In addition, since it is possible to set a retransmission interval according to the time required for the control packet CP to circulate through the wireless stations to be routed, a situation in which a plurality of control packets CP circulate each wireless station in the wireless communication system 301 can be set. It can be avoided. Thereby, it is possible to avoid a communication failure due to interference between radio waves including the control packet CP.

  In the radio communication system according to the first embodiment of the present invention, serial packets SP are transmitted at intervals. And the transmission interval of serial packet SP is set to the length according to the transmission rate of traffic information.

  With such a configuration, it is possible to set a transmission interval according to the time required for transmission / reception of the serial packet SP between the master station 101 and the corresponding relay station 151 or slave station 202. A situation in which data is transmitted / received between wireless stations in the communication system 301 can be avoided. Thereby, it is possible to avoid a communication failure due to interference between radio waves including the serial packet SP.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to a wireless communication system in which the communication method of communication packets is changed as compared with the wireless communication system according to the first embodiment. The contents other than those described below are the same as those of the wireless communication system according to the first embodiment.

  FIG. 29 is a diagram illustrating an application example of the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 29, a wireless communication system 301 is used for a traffic control system 402, for example. The traffic control system 402 includes a main station 101, a relay station 151, two slave stations 202, a central communication device 160, an image sensor 163, and an ultrasonic sensor 164. The central communication device 160, the image sensor 163, and the ultrasonic sensor 164 correspond to terminals.

  The traffic control system 402 may include one slave station 202 or three or more slave stations 202. Further, the traffic control system 402 may not include the relay station 151 or may include two or more relay stations 151. The traffic control system 402 may include the traffic signal 161 and the optical beacon 162 shown in FIG.

  Since central communication device 160, image sensor 163, and ultrasonic sensor 164 are similar to central communication device 160, image sensor 163, and ultrasonic sensor 164 shown in FIG. 2, detailed description will not be repeated.

  The slave station 202 connected to the ultrasonic sensor 164 samples, for example, the contact signal PS1 shown in FIG. 3 received from the ultrasonic sensor 164, and generates a digital value as a contact result as contact information. The sampling period of the contact signal is, for example, 10 milliseconds. The contact signal sampling period may be, for example, 5 milliseconds. Hereinafter, the slave station 202 connected to the ultrasonic sensor 164 is also referred to as a contact information generation station.

  Specifically, the contact information generation station generates contact information P11 to P16, for example, at times t11 to t16. For example, the contact information generation station transmits the generated contact information P11 to P16 to the main station 101 via the relay station 151 on a peer-to-peer basis.

  In the example shown in FIG. 29, the contact information generation station transmits the contact information to the main station 101 via the relay station 151, but the present invention is not limited to this. The contact information generation station may directly transmit the contact information to the main station 101, for example.

  When the main station 101 receives the contact information P11 to P16 from the contact information generation station, the main station 101 generates the contact signal PS2 based on the received contact information P11 to P16.

  More specifically, the main station 101 generates the contact signal PS2 by performing DA (digital analog) conversion on the contact information P11 to P16 every 10 milliseconds at times t21 to t26, for example.

  That is, in the main station 101, the contact signal PS1 received from the ultrasonic sensor 164 by the contact information generation station is generated as the contact signal PS2. Then, the main station 101 transmits the generated contact signal PS2 to the central communication device 160 by wire.

  Further, for example, serial information is transmitted and received between the central communication device 160 and the ultrasonic sensor 164 and the image sensor 163 on a peer-to-peer basis.

  The relay station 151 relays contact information and serial information transmitted / received peer-to-peer between the master station 101 and the slave station 202.

[Task]
For example, when the TDMA method is used in a radio section in a traffic control system, the delay time and transmission order of contact information can be controlled, but the following problems arise. That is, a general-purpose wireless LAN module often operates as a standard operation in the CSMA / CA system. Therefore, when the wireless LAN module is used in the TDMA system, it is necessary to customize a driver used for the standard operation, which increases development costs. It will take.

  Further, in the TDMA system, the number of slots that can be allocated depends on the transmission speed and the amount of communication data, so the number of network configurations and the network configuration are limited. That is, the degree of freedom in designing the network is limited.

  On the other hand, when the CSMA / CA method is used, the degree of freedom in designing the network can be increased, but the delay time cannot be controlled. For this reason, the contact information may not be transmitted within an allowable delay time defined in the traffic control system.

  In the CSMA / CA system, for example, even if the contact information generation station attempts to transmit to the main station in the order in which the contact information is generated, the main station may not be able to receive the contact information in that order. Specifically, for example, even if the contact information generation station attempts to transmit contact information to the main station in the order of P11, P12, and P13, the main station may receive the contact information in the order of P11, P13, and P12.

  More specifically, even if the contact information generation station stores the contact information in the transmission buffer, that is, the transmission queue in the order in which the contact information is generated, the order of the contact information may be switched in the transmission queue. In particular, the shorter the time interval at which contact information is generated, that is, the shorter the contact information transmission interval, the easier the order change occurs. Also, when the contact information generating station transmits contact information to the main station via the relay station, the order of transmission may be changed at the relay station.

  For example, as shown in S6 interface standard, New Traffic Management System Association, March 18, 1999, edition 2, P5-9 (Non-patent Document 1), serial information includes a transmission order number or a reception order. Number and serial number are stored.

  Therefore, for example, when the slave station transmits the contact information and serial information in the same packet, the master station is based on the transmission sequence number or reception sequence number stored in the serial information included in the received packet, and the serial number. In some cases, the order of contact information can be returned to the correct order.

  However, when a slave station that does not transmit / receive serial information transmits contact information to the master station, the master station cannot correctly return the order of the received contact information.

  Further, for example, serial information is newly generated every 1 to several seconds, whereas contact information is generated every 10 milliseconds. As a configuration that can flexibly cope with a difference in information generation cycle, there is a case where the slave station wants to transmit the contact information and serial information in separate packets. In this case, since the main station receives the contact information and the serial information separately, the main station cannot return the order of the contact information to the correct order based on the transmission order number or the reception order number and the serial number.

  Further, for example, when a plurality of ultrasonic sensors 164 are connected to the contact information generation station, the following problem may occur. That is, the contact information generation station obtains contact information PI3 based on the contact signal received from one ultrasonic sensor 164, which is contact information based on the contact signal received from another ultrasonic sensor 164, at an earlier timing than the contact information PI3. In some cases, the generated contact information PI4 is transmitted before the contact information PI4. In this case, the main station receives the contact information PI4 at a delayed timing.

  Even in a busy state where a plurality of slave stations are trying to transmit information, the master station may receive contact information at a delayed timing.

  If the timing at which the main station receives the contact information is delayed, the timing at which the terminal receives the contact signal is also delayed, which is not preferable.

  Therefore, the wireless communication system according to the second embodiment of the present invention solves such a problem by the following configuration and operation.

  FIG. 30 is a diagram illustrating an example of a communication packet transmitted and received by a wireless station configuring the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 30, a communication packet is composed of, for example, “header”, “data”, “postheader”, and “postamble” in the order of transmission.

  In the “header”, an ID, a slot / node number, an operation mode, a frequency channel, a time stamp, and a CRC can be stored. In “Data”, data type, contact information, CRC and pmask information can be stored.

  The “post header” has an area of the same size as the “header”, and can store a copy of the contents of the “header”. The “postamble” can store a value used as a delimiter. The value stored in each field will be described later.

  FIG. 31 is a diagram illustrating a configuration of a wireless communication device in a wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 31, the wireless communication device 92 can be used as the master station 101, the relay station 151, or the slave station 202. The antenna 10, the wireless communication unit 11, the wired communication unit 12, the storage unit 17, Wireless side priority setting unit 51, reception state monitoring unit 52, wireless transmission queue 53, communication control unit (packet transmission unit) 54, serial packet processing unit (packet generation unit) 55, contact packet processing unit (Contact processing unit and packet generation unit) 56, a counter 57, a contact information processing unit (contact processing unit) 58, a wired-side priority setting unit 59, and a wired transmission queue 60. For example, the counter 57 outputs a count value indicating the current time.

  Since the antenna 10, the wireless communication unit 11, the wired communication unit 12, and the storage unit 17 are the same as the antenna 10, the wireless communication unit 11, the wired communication unit 12, and the storage unit 17 shown in FIG. 7, detailed description will be repeated. Absent.

(Transmission of contact information and serial information)
For example, the contact information processing unit 58 generates a plurality of contact information in time series. Specifically, for example, the contact information processing unit 58 samples a contact signal received from a terminal connected to its own wireless communication device 92 every 10 milliseconds, and sequentially uses a digital value as a sampling result as contact information. Generate. The contact information processing unit 58 outputs the generated contact information to the contact packet processing unit 56.

  For example, when the contact packet processing unit 56 receives contact information from the contact information processing unit 58, the contact packet processing unit 56 adds time information to the received contact information. Specifically, the contact packet processing unit 56 adds, for example, time information indicating the time when the contact information is generated to the contact information. More specifically, for example, the contact packet processing unit 56 acquires the count value output by the counter 57 at the timing when the contact information is received, and stores the acquired count value in association with the contact information.

  The contact packet processing unit 56 generates, for example, a contact packet PPd that is a communication packet including the contact information and sets a value indicating that the communication packet is a contact packet in the data type of the communication packet.

  At this time, for example, the contact packet processing unit 56 sets the count value stored in association with the contact information as a time stamp in the contact packet PPd as time information. In addition, the contact packet processing unit 56 appropriately sets a value in each field in the contact packet PPd, for example.

  For example, each time the contact packet processing unit 56 receives contact information for one sample from the contact information processing unit 58, the contact packet processing unit 56 generates a contact packet PPd including the contact information. The contact packet processing unit 56 may generate, for example, contact packets PPd including contact information for 20 samples after accumulating 20 samples of contact information received from the contact information processing unit 58. The contact packet processing unit 56 outputs the generated contact packet PPd to the wireless transmission queue 53.

  When receiving serial information from the terminal via the wired communication unit 12, the serial packet processing unit 55 generates a serial packet SPd that is a communication packet including the received serial information and is a packet separate from the contact packet PPd.

  The serial packet processing unit 55 stores a value indicating that the serial packet SPd is a serial packet in the data type. Further, the serial packet processing unit 55 stores, for example, null in the time stamp in the serial packet SPd. The serial packet processing unit 55 outputs the generated serial packet SPd to the wireless transmission queue 53.

  The communication control unit 54 processes a communication packet received via the wireless communication unit 11. More specifically, when the communication control unit 54 receives, for example, the serial packet SPd and the contact packet PPd to be relayed to another wireless communication device 92 via the wireless communication unit 11, the received serial packet SPd and contact packet PPd are received. Is output to the wireless transmission queue 53.

  The wireless transmission queue 53 is, for example, a buffer, and receives communication packets generated by the serial packet processing unit 55 and the contact packet processing unit 56 and communication packets to be relayed received from other wireless stations via the communication control unit 54. accumulate.

  For example, the wireless-side priority setting unit 51 monitors communication packets stored in the wireless transmission queue 53, and prioritizes communication packets stored in the wireless transmission queue 53 based on the type and time information of the communication packet. Set the degree.

  Specifically, the wireless-side priority setting unit 51 stores, for example, contact packets generated within a predetermined time from communication packets stored in the wireless transmission queue 53 based on time information. Set PPd priority high.

  More specifically, when the contact packet PPd is accumulated in the wireless transmission queue 53, for example, the wireless-side priority setting unit 51 includes the time information stored in the contact packet PPd and the count value output by the counter 57. Calculate the difference between

  The wireless-side priority setting unit 51 calculates, for example, an elapsed time after the contact information stored in the contact packet PPd is generated based on the calculated difference, and the calculated elapsed time is a predetermined time, for example, 300 mm. If it is within seconds, the following processing is performed.

  That is, the wireless-side priority setting unit 51 sets, for example, the priority of the contact packet PPd higher than the priority of the serial packet SPd. Further, the wireless-side priority setting unit 51 sets a higher priority for the contact packet PPd storing old contact information, for example, based on the time information stored in the contact packet PPd.

  More specifically, the wireless-side priority setting unit 51 determines that when the target contact packet PPd0 is stored in the wireless transmission queue 53 in a state where the serial packet SPd is stored in the wireless transmission queue 53, the contact packet The priority of PPd0 is set higher than the priority of serial packet SPd.

  For example, when the target contact packet PPd1 is stored in a state where the contact packet PPd0 is stored in the buffer, the wireless-side priority setting unit 51 sets time information of the contact packet PPd0 and time information of the contact packet PPd1. And set the priority according to the comparison result.

  Specifically, for example, when the time information of the contact packet PPd0 indicates a time older than the time information of the contact packet PPd1, the wireless-side priority setting unit 51 sets the priority of the contact packet PPd1 lower than that of the contact packet PPd0 and serially. Set higher than packet SPd.

  For example, when the time information of the contact packet PPd1 indicates a time older than the time information of the contact packet PPd0, the wireless-side priority setting unit 51 sets the priority of the contact packet PPd1 higher than that of the contact packet PPd0 and the serial packet SPd. To do.

  By repeating such processing, for example, when one or more target contact packets PPd and one or more serial packets SPd are accumulated in the wireless transmission queue 53, the priority of the target contact packet PPd is given priority. The degree is higher than the priority of any serial packet SPd. In addition, the priority of the target contact packet PPd accumulated in the wireless transmission queue 53 is higher in the order of older time information.

  For example, the communication control unit 54 determines whether or not another radio station is transmitting a radio signal, and determines that the other radio station is not transmitting a radio signal. Each accumulated communication packet is transmitted via the wireless communication unit 11.

  At this time, for example, the communication control unit 54 gives priority to the contact packet PPd including the contact information generated within a predetermined time among the communication packets stored in the wireless transmission queue 53 based on the time information. Send.

  Specifically, the communication control unit 54 transmits the communication packets stored in the wireless transmission queue 53 via the wireless communication unit 11 in descending order of priority set in the communication packet, for example, according to the CSMA / CA method. To do. At this time, the communication control unit 54 sets the transmission destination wireless communication device 92 based on, for example, the station number of the wireless station that is the destination of the communication packet and the entry table stored in the storage unit 17.

  For example, the communication control unit 54 starts carrier sense at a timing when communication packets to be transmitted are accumulated in the wireless transmission queue 53. More specifically, the communication control unit 54 outputs a reception state notification request to the reception state monitoring unit 52.

  When the reception state monitoring unit 52 receives the reception state notification request from the communication control unit 54, the reception state monitoring unit 52 monitors whether or not a wireless signal from another wireless station is received in the wireless communication unit 11, and performs communication by the communication control unit 54. The monitoring result is output to the communication control unit 54 until the packet transmission is completed. Here, the other radio stations are, for example, the master station 101, the relay station 151, the slave station 202, and radio transmitters such as an in-vehicle device and an access point.

  Specifically, the reception state monitoring unit 52 outputs a busy notification to the communication control unit 54 when, for example, a wireless signal from another wireless station is received in the wireless communication unit 11, and the wireless communication unit 11 When no wireless signal is received from another wireless station, an idle notification is output to the communication control unit 54.

  For example, upon receiving an idle notification from the reception state monitoring unit 52, the communication control unit 54 waits for a random backoff time. For example, when receiving an idle notification from the reception state monitoring unit 52 even after standby, the communication control unit 54 acquires a communication packet having the highest priority among the communication packets stored in the wireless transmission queue 53, The acquired communication packet is transmitted to the destination wireless communication device 92 via the wireless communication unit 11.

  For example, when receiving a busy notification from the reception state monitoring unit 52, the communication control unit 54 stands by while receiving the busy notification. Then, for example, after the notification received from the reception state monitoring unit 52 changes from the busy notification to the idle notification, the reception state monitoring unit 52 further waits for an IFS (Inter Frame Space) time.

  Then, for example, after waiting for the IFS time, the communication control unit 54 further waits for the back-off time. For example, when receiving an idle notification from the reception state monitoring unit 52 even after standby, the communication control unit 54 acquires a communication packet having the highest priority among the communication packets stored in the wireless transmission queue 53, The acquired communication packet is transmitted to the destination wireless communication device 92 via the wireless communication unit 11.

(Reception of contact information and serial information)
For example, when the communication control unit 54 receives a communication packet addressed to its own wireless communication device 92 via the wireless communication unit 11, the communication control unit 54 determines the type of the received communication packet. Specifically, for example, the communication control unit 54 refers to a value stored in the data type in the communication packet, and determines the type of the communication packet based on the referenced value.

  Note that the communication control unit 54 refers to, for example, a value stored in a time stamp in the communication packet, and determines that the type of the communication packet is a serial packet SPd when the value is null. When the value is a value other than null, it may be determined that the type of the communication packet is the contact packet PPd.

  For example, the communication control unit 54 outputs the communication packet determined to be the contact packet PPd to the contact packet processing unit 56, and outputs the communication packet determined to be the serial packet SPd to the serial packet processing unit 55.

  For example, when receiving the contact packet PPd from the communication control unit 54, the contact packet processing unit 56 acquires the contact information and the value stored in the time stamp, that is, the time information, from the received contact packet PPd, and the acquired contact information and The time information is output to the contact information processing unit 58 and the wired transmission queue 60.

  Upon receiving contact information and time information from the contact packet processing unit 56, the contact information processing unit 58 accumulates the received contact information. For example, the contact information processing unit 58 rearranges a plurality of accumulated contact information based on time information added to the plurality of contact information, in chronological order, specifically in the oldest order.

  The contact information processing unit 58 acquires the contact information for one sample at a timing when the difference between the count value output from the counter 57 and the time information corresponding to the oldest contact information becomes a predetermined value, and the acquired one sample. A contact signal having a level corresponding to the value indicated by the contact information is generated. The contact information processing unit 58 transmits the generated contact signal to the terminal via the wired communication unit 12.

  For example, when the contact information processing unit 58 processes all accumulated contact information and cannot receive new contact information from the contact packet processing unit 56, the contact information processing unit 58 is a predetermined time, specifically, the maximum allowable contact signal 400. Wait milliseconds. At this time, the contact information processing unit 58 generates, for example, a high-level contact signal. Note that the contact information processing unit 58 may generate, for example, a low-level contact signal or may not generate a contact signal.

  For example, if the new contact information cannot be received from the contact packet processing unit 56 even after waiting for 400 milliseconds, the contact information processing unit 58 generates a high-level contact signal for another 50 milliseconds.

  The contact information processing unit 58 repeats the process of generating a high-level contact signal for 50 milliseconds until new contact information is received from the contact packet processing unit 56, for example.

  For example, when the contact information processing unit 58 receives new contact information and time information from the contact packet processing unit 56 while generating a high-level contact signal, the count value output by the counter 57 and the received time information are received. And the difference is calculated. For example, when the difference is larger than the predetermined value, the contact information processing unit 58 recognizes that the received contact information is delayed and discards the contact information.

  Thereby, since it can avoid producing | generating the delayed contact signal based on the delayed contact information, a more correct contact signal can be generated temporally.

  Further, for example, when the difference is smaller than the predetermined value, the contact information processing unit 58 generates a contact signal from the contact information at a timing when the difference becomes the predetermined value.

  For example, when receiving the serial packet SPd from the communication control unit 54, the serial packet processing unit 55 acquires serial information from the received serial packet SPd and outputs the acquired serial information to the wired transmission queue 60.

  Wired transmission queue 60 is a buffer, for example, and stores serial information, contact information, and time information received when serial information and contact information and time information are received from serial packet processing unit 55 and contact packet processing unit 56, respectively. .

  The wired-side priority setting unit 59 monitors serial information, contact information, and time information accumulated in the wired transmission queue 60, and serials accumulated in the wired transmission queue 60 based on the type of information and time information. Set the priority of information and contact information.

  Specifically, the wired side priority setting unit 59 sets the priority of the contact information higher than the priority of the serial information. The wired-side priority setting unit 59 sets a higher priority for older contact information based on the time information.

  For example, the wired communication unit 12 acquires the highest priority information among the serial information and contact information stored in the wired transmission queue 60, and sends the acquired information to a terminal connected to its own wireless communication device 92. Send.

  As a result, the wireless communication device 92 can transmit the contact information to the terminal connected to the wireless communication device 92 in time-series order and with priority over the serial information.

[Operation]
FIG. 32 is a flowchart defining an operation procedure when a slave station transmits a communication packet in the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 32, first, serial packet processing unit 55 in slave station 202 waits until serial information is received from wired communication unit 12. The contact packet processing unit 56 stands by until contact information is received from the contact information processing unit 58 (NO in step S302 and NO in step S304).

  Next, when the serial packet processing unit 55 receives serial information transmitted from a terminal connected to its own wireless communication device 92 from the wired communication unit 12, the serial packet processing unit 55 generates a serial packet SPd based on the received serial information ( YES in step S302).

  Next, the serial packet processing unit 55 accumulates the generated serial packet SPd in the wireless transmission queue 53 (step S306).

  Further, when receiving the contact information from the contact information processing unit 58, the contact packet processing unit 56 generates the contact packet PPd including the contact information and the corresponding time information (YES in step S304).

  Next, the contact packet processing unit 56 accumulates the generated contact packet PPd in the wireless transmission queue 53 (step S306).

  Next, when the contact packet PPd is newly accumulated in the wireless transmission queue 53 (YES in step S308), the wireless-side priority setting unit 51, for example, sets the priority of the new contact packet PPd to the wireless transmission. The priority is set higher than the priority of the serial packet SPd stored in the queue 53 (step S310).

  Next, the wireless-side priority setting unit 51 performs the following processing based on the comparison result between the time information of the new contact packet PPd and the time information of the contact packet PPd stored in the wireless transmission queue 53. Do. That is, the wireless-side priority setting unit 51, for example, in the wireless transmission queue 53 after accumulating new contact packets PPd, new contact points so that the priorities of the time information of the contact packets PPd become higher in order from the oldest. The priority of the packet PPd is set (step S312).

  Next, the serial packet processing unit 55 stands by until serial information is received from the wired communication unit 12. The contact packet processing unit 56 stands by until contact information is received from the contact information processing unit 58 (NO in step S302 and NO in step S304).

  Further, when the serial packet SPd is newly accumulated in the wireless transmission queue 53 (NO in step S308), the wireless-side priority setting unit 51 does not perform any particular processing, and the serial packet processing unit 55 Wait until serial information is received from 12. The contact packet processing unit 56 stands by until contact information is received from the contact information processing unit 58 (NO in step S302 and NO in step S304).

  The process for setting the priority of the new contact packet PPd higher than the priority of the serial packet SPd stored in the wireless transmission queue 53 (step S306), and for the wireless after storing the new contact packet PPd In the transmission queue 53, the order of the process of setting the priority of the new contact packet PPd (step S308) may be changed so that the priorities of the time information of the contact packet PPd become higher in the oldest order.

  FIG. 33 is a flowchart defining an operation procedure when a relay station relays a communication packet in the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 33, first, communication control unit 54 in relay station 151 receives, for example, a communication packet to be relayed to another wireless station from slave station 202 or other relay station 151 via wireless communication unit 11. Wait (NO in step S402).

  Next, when receiving a communication packet to be relayed to another wireless station via the wireless communication unit 11 (YES in step S402), the communication control unit 54 outputs the received communication packet to the wireless transmission queue 53. The wireless-side priority setting unit 51 checks whether or not the communication packet newly accumulated in the wireless transmission queue 53 is a contact packet PPd (step S404).

  Next, when the communication packet is the contact packet PPd (YES in step S404), the wireless-side priority setting unit 51 has elapsed since the generation of the contact information stored in the newly accumulated contact packet PPd. The time is calculated, and if the calculated elapsed time is within the predetermined time (YES in step S406), the following processing is performed.

  That is, for example, the wireless-side priority setting unit 51 sets the priority of the new contact packet PPd higher than the priority of the serial packet SPd stored in the wireless transmission queue 53 (step S408).

  Next, the wireless-side priority setting unit 51 performs the following processing based on the comparison result between the time information of the new contact packet PPd and the time information of the contact packet PPd stored in the wireless transmission queue 53. Do. That is, the wireless-side priority setting unit 51, for example, in the wireless transmission queue 53 after accumulating new contact packets PPd, new contact points so that the priorities of the time information of the contact packets PPd become higher in order from the oldest. The priority of the packet PPd is set (step S410).

  Next, for example, the communication control unit 54 waits until a communication packet to be relayed to another wireless station is received from the slave station 202 or another relay station 151 via the wireless communication unit 11 (NO in step S402).

  Also, if the calculated elapsed time exceeds the predetermined time (NO in step S406), the radio side priority setting unit 51 does not perform any particular processing, and the communication control unit 54 should relay to another radio station. Wait until a communication packet is received from the slave station 202 or another relay station 151 via the wireless communication unit 11 (NO in step S402).

  Further, when the communication packet is a serial packet SPd (NO in step S404), the communication control unit 54, for example, transmits a communication packet to be relayed to another wireless station from the slave station 202 or the other relay station 151 to the wireless communication unit. 11 until it is received via 11 (NO in step S402).

  The relay station 151 is configured to set the priority of communication packets to be relayed to other wireless stations received from the slave station 202 or other relay stations 151, but is not limited to this. For example, the relay station 151 should generate a communication packet including information received from a terminal connected to the relay station 151 and relay it to the generated communication packet and another wireless station received from the slave station 202 or another relay station 151. You may set the priority of a communication packet.

  FIG. 34 is a flowchart defining an operation procedure when setting the priority of communication packets received by the main station in the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 34, first, communication control unit 54 in master station 101 waits until serial packet SPd addressed to itself is received from slave station 202 or another relay station 151 via wireless communication unit 11, for example. Further, for example, the communication control unit 54 waits until the contact packet PPd addressed to itself is received from the slave station 202 or another relay station 151 via the wireless communication unit 11 (NO in step S502 and NO in step S504).

  Next, when the communication control unit 54 receives the contact packet PPd addressed to itself through the wireless communication unit 11, the communication control unit 54 outputs the received contact packet PPd to the contact packet processing unit 56. The contact packet processing unit 56 acquires contact information and time information from the contact packet PPd received from the communication control unit 54, and outputs the acquired contact information and time information to the contact information processing unit 58 and the wire transmission queue 60 ( NO in step S502 and YES in step S504).

  Next, when the contact information processing unit 58 receives the contact information and time information from the contact packet processing unit 56, the contact information processing unit 58 accumulates the contact information, and rearranges the accumulated contact information in chronological order based on the time information (step S506). ).

  Next, the wired-side priority setting unit 59 sets the priority of the contact information in the wired transmission queue 60 to be higher than the priority of the serial information (step S508).

  Next, the wired-side priority setting unit 59 sets a higher priority for older contact information in the wired transmission queue 60 based on the time information (step S510).

  Next, for example, the communication control unit 54 waits until the serial packet SPd addressed to itself is received from the slave station 202 or another relay station 151 via the wireless communication unit 11. Further, for example, the communication control unit 54 waits until the contact packet PPd addressed to itself is received from the slave station 202 or another relay station 151 via the wireless communication unit 11 (NO in step S502 and NO in step S504).

  Further, when the communication control unit 54 receives the serial packet SPd addressed to the local station via the wireless communication unit 11, the communication control unit 54 outputs the received serial packet SPd to the serial packet processing unit 55 (YES in step S502).

  Next, when receiving the serial packet SPd from the communication control unit 54, the serial packet processing unit 55 acquires serial information from the received serial packet SPd and outputs the acquired serial information to the wired transmission queue 60 (step S512). ).

  Next, for example, the communication control unit 54 waits until the serial packet SPd addressed to itself is received from the slave station 202 or another relay station 151 via the wireless communication unit 11. Further, for example, the communication control unit 54 waits until the contact packet PPd addressed to itself is received from the slave station 202 or another relay station 151 via the wireless communication unit 11 (NO in step S502 and NO in step S504).

  A process for setting the priority of the contact information higher than the priority of the serial information (step 508), and a process for setting a higher priority for older contact information in the wired transmission queue 60 based on the time information (step 510). ) May be changed.

  Further, the contact information processing unit 58 sorts the accumulated contact information in time series based on the time information (step 506), and the wired-side priority setting unit 59 prioritizes the contact information in the wired transmission queue 60. The order of the process of setting the degree (step 508 and step S510) may be changed.

  FIG. 35 is a flowchart defining an operation procedure when generating a contact signal from contact information received by the main station in the wireless communication system according to the second embodiment of the present invention.

  FIG. 35 shows an operation in which the contact information processing unit 58 in the main station 101 generates a contact signal based on the contact information rearranged in time series in step S506 shown in FIG.

  Referring to FIG. 35, first, the contact information processing unit 58 checks whether or not all the contact information rearranged in chronological order has been processed (step S552). When all the contact information rearranged in time series is processed, the contact information processing unit 58 continuously generates, for example, a high-level contact signal (YES in step S552 and step S562).

  On the other hand, when the contact information processing unit 58 has not processed all the contact information rearranged in the time series order (NO in step S552), the contact information rearranged in the time series and the count value output by the counter 57 is used. A difference Dt from the time information corresponding to the oldest contact information is calculated (step S554).

  Next, when the difference Dt is larger than the predetermined value (YES in step S556), the contact information processing unit 58 discards the contact information (step S558).

  Next, the contact information processing unit 58 checks whether or not all contact information rearranged in chronological order has been processed (step S552).

  Further, when the difference Dt is equal to or smaller than the predetermined value (NO in step S556), the contact information processing unit 58 generates a contact signal from the contact information at a timing when the difference Dt becomes the predetermined value (step S560).

  Next, the contact information processing unit 58 checks whether or not all contact information rearranged in chronological order has been processed (step S552).

  FIG. 36 is a diagram illustrating an example of a sequence when contact information and serial information are transmitted to the main station according to priority in the wireless communication system according to the second embodiment of the present invention.

  Referring to FIG. 36, for example, as shown in FIG. 29, the slave station 202 connected to the ultrasonic sensor 164, that is, the contact information generation station and the slave station 202 connected to the image sensor 163 receive the contact information and serial information, respectively. Assume a situation in which transmission is attempted to the main station 101 via the relay station 151.

  First, the contact information generation station generates, for example, the contact information P12 sampled at time t12 shown in FIG. 3 and the contact packet PPd12 storing time t12 as time information, and transmits the generated contact packet PPd12 to the relay station 151. (Step S602).

  Next, the slave station 202 connected to the image sensor 163 generates, for example, the serial packet SPd1 storing the serial information S1, and transmits the generated serial packet SPd1 to the relay station 151 (step S604).

  Next, the slave station 202 connected to the image sensor 163 generates, for example, the serial packet SPd2 storing the serial information S2, and transmits the generated serial packet SPd2 to the relay station 151 (step S606).

  Next, the contact information generating station generates, for example, contact information P13 sampled at time t13 shown in FIG. 3 and contact packet PPd13 storing time t13 as time information, and the generated contact packet PPd13 is transmitted to relay station 151. Transmit (step S608).

  Next, when the relay station 151 receives the contact packet PPd12, the serial packet SPd1, the serial packet SPd2, and the contact packet PPd13 in this order from the contact information generation station and the slave station 202 connected to the image sensor 163, the relay station 151 performs the following processing.

  That is, relay station 151 sets a higher priority in the order of contact packet PPd12, contact packet PPd13, serial packet SPd1, and serial packet SPd2 based on the type and time information of the communication packet (step S610).

  Next, the relay station 151 transmits the contact packet PPd12 having the highest priority to the main station 101 (step S612).

  Next, the relay station 151 transmits the contact packet PPd13 having the second priority to the main station 101 (step S614).

  Next, the relay station 151 transmits the serial packet SPd1 having the third priority to the main station 101 (step S616).

  Next, the relay station 151 transmits the serial packet SPd2 having the fourth priority to the main station 101 (step S618).

  Next, the main station 101 generates contact information P12 and P13 stored in the contact packets PPd12 and PPd13 received from the relay station 151 at times t22 and t23 shown in FIG. 3 (step S620).

  Although the master station according to the second embodiment of the present invention is configured to receive contact information from the slave station 202 and the relay station 151, the present invention is not limited to this. For example, the master station may be configured to transmit contact information generated by itself and contact information received from the slave station 202 and the relay station 151 to another slave station 202 or another relay station 151.

  As described above, in the wireless communication system according to the second embodiment of the present invention, the slave station 202 generates a plurality of contact information in time series, and adds time information to each generated contact information. The slave station 202 includes the contact information and serial information to which time information is added in the contact packet PPd and the serial packet SPd, respectively, and transmits it to the master station 101. The slave station 202 determines whether or not another radio station is transmitting a radio signal, and transmits the contact packet PPd and the serial packet SPd when it is determined that the other radio station is not transmitting the radio signal. . Then, the main station 101 acquires contact information from each of the received contact packets PPd, and rearranges the contact information in chronological order based on the time information added to the acquired contact information.

  As described above, when the slave station 202 determines that the wireless signal is not transmitted by another wireless station, the configuration in which the contact packet PPd and the serial packet SPd are transmitted can reduce the probability of occurrence of a communication failure due to interference or the like. it can. Thereby, it can avoid that transmission of traffic information fails between traffic facilities, and traffic information can be more reliably transmitted between traffic facilities.

  For example, even when a plurality of contact packets PPd are transmitted according to the CSMA / CA method in which the order of packet transmission is likely to change, the main station 101 is included in the plurality of contact packets PPd based on the time information. Each contact information can be correctly sorted in the order of generation.

  In addition, since it is not necessary to customize the driver used for the standard operation of the general-purpose wireless LAN module, the manufacturing cost of the master station 101, the relay station 151, and the slave station 202 can be reduced, and the freedom in designing the network can be reduced. The degree can be increased.

  Further, in the wireless communication system according to the second embodiment of the present invention, relay station 151 uses, based on the time information, out of each received contact packet PPd and serial packet SPd, a contact generated within a predetermined time. The contact packet PPd including information is relayed with priority.

  As described above, the configuration in which the contact packet PPd including contact information that is new to some extent is preferentially relayed, so that the delay time of the contact information can be further shortened, and the possibility of satisfying the delay time requirement in the traffic control system is increased. be able to.

  Since other configurations and operations are the same as those of the wireless communication apparatus according to the first embodiment, detailed description thereof will not be repeated here.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The above description includes the following features.

[Appendix 1]
A wireless communication system comprising a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations,
The master station is capable of transmitting communication packets at predetermined intervals to the slave station,
In response to receiving the communication packet, the slave station transmits the communication packet or another communication packet,
The communication packet can store communication quality information of the wireless station and can pass through the wireless station, and a serial packet transmitted / received between the corresponding slave station and the parent station And
The master station can transmit a communication packet to the slave station in slot units,
In response to receiving the communication packet, the slave station transmits the communication packet or the communication packet with the contents rewritten,
The communication packet can store RSSI and noise level as communication quality information of the wireless station and can pass through the wireless station, and between the corresponding slave station and the parent station. A wireless communication system including serial packets to be transmitted and received.

[Appendix 2]
A wireless communication system comprising a master station and a slave station that are wireless stations for wirelessly transmitting traffic information,
The traffic information includes contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the radio station,
The slave station is
A plurality of the contact information in time series, a contact processing unit for adding time information to each generated contact information;
A packet generation unit including the contact information to which the time information is added by the contact processing unit and the serial information in a separate packet;
A packet transmission unit that determines whether another wireless station is transmitting a wireless signal and that transmits the packet when it is determined that the other wireless station is not transmitting a wireless signal;
The main station acquires the contact information from each of the received plurality of packets, and rearranges the contact information in chronological order based on the time information added to the acquired contact information,
The packet generation unit includes the contact information to which the time information is added by the contact processing unit, and the serial information in a contact packet and a serial packet, respectively.
The said packet transmission part is a radio | wireless communications system which transmits the said contact packet and the said serial packet according to a CSMA / CA system.

DESCRIPTION OF SYMBOLS 10 Antenna 11 Wireless communication part 12 Wired communication part 13 Packet processing part 14 Operation part 15 External command processing part 16 Contact information processing part 17 Memory | storage part 18 Contact information 1st buffer 19 Contact information 2nd buffer 20 Output part 31 Packet path | route judgment part 32 packet management unit 33 serial packet processing unit 34 control packet processing unit 35 serial packet management unit 36 control packet management unit 37 timer 38 schedule creation unit 39 transmission failure number counter unit 41 CP reception state setting unit 42 transfer processing unit 43 retransmission processing unit 44 Recovery Notification Packet Processing Unit 51 Wireless Side Priority Setting Unit 52 Reception Status Monitoring Unit 53 Wireless Transmission Queue 54 Communication Control Unit (Packet Transmission Unit)
55 Serial packet processor (packet generator)
56 Contact packet processor (contact processor and packet generator)
57 Counter 58 Contact Information Processing Unit (Contact Processing Unit)
59 Wired-side priority setting unit 60 Wired transmission queue 91, 92 Wireless communication device 101 Main station (master station)
151 Relay station (slave station)
160 Central communication equipment (TTR)
161 Traffic signal 162 Optical beacon 163 Image sensor 164 Ultrasonic sensor 201 Wireless LAN network 202 Slave station (slave station)
301 Wireless communication system 401, 402 Traffic control system AG terminal

Claims (19)

A wireless communication system comprising a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations,
The master station is capable of transmitting communication packets at predetermined intervals to the slave station,
In response to receiving the communication packet, the slave station transmits the communication packet or another communication packet,
The communication packet can store communication quality information of the wireless station and can pass through the wireless station, and a serial packet transmitted / received between the corresponding slave station and the parent station And a wireless communication system. The control packet is retransmitted when it is determined that it has not been possible to return to the predetermined radio station via the slave station or the master station,
The wireless communication system according to claim 1, wherein the serial packet having the same content as the previously transmitted serial packet is repeatedly transmitted until new information to be included in the serial packet is acquired. The traffic information includes contact information indicating whether or not a vehicle is detected, and serial information which is information different from the contact information and is information from a terminal connected to the master station or the slave station,
The control packet can further store the contact information,
The serial packet can store the serial information,
The radio communication system according to claim 1 or 2, wherein at least one of the master station and the slave station can store the communication quality information and the contact information in the control packet. When the information contained in the received control packet is the same as the information contained in the previously received control packet, the slave station receives the control packet last time and transmits the control packet transmitted to another station to the other station. Resend to the station,
The slave station has received this time when the received control packet includes information addressed to itself and the information contained in the received control packet is different from the information contained in the previously received control packet. Send information addressed to the station to the terminal connected to the station,
When the slave station includes the information addressed to the local station in the received control packet, and the information included in the received control packet is the same as the information included in the previously received control packet, The wireless communication system according to any one of claims 1 to 3, wherein the received information addressed to the own station is discarded. When the slave station does not include the information addressed to the local station in the received serial packet, the slave station transmits the serial packet received this time to another station,
The slave station has received this time when the received serial packet includes information addressed to itself and the information included in the received serial packet is different from the information included in the previously received serial packet. Send information addressed to the station to the terminal connected to the station,
When the slave station includes the information addressed to the local station in the received serial packet, and the information included in the received serial packet is the same as the information included in the previously received serial packet, The wireless communication system according to any one of claims 1 to 4, wherein the received information addressed to the own station is discarded.   Even if the master station or the slave station transmits the control packet a predetermined number of times to the subordinate station that is the slave station connected to the slave station on the downstream side from the master station to the slave station, When the control packet or the response of the control packet does not return from the lower station to the own station, the lower station is excluded from the transmission destination of the control packet, and the upper station from the lower station to the parent station with respect to the own station The wireless communication system according to any one of claims 1 to 5, wherein the control packet is transmitted to the upper station, which is the master station or the slave station connected to the direction side, or to another lower station. .   The wireless communication according to claim 6, wherein when the lower station does not receive the control packet for a predetermined time from the upper station, the lower station transmits a recovery notification for notifying that the own station has recovered to the upper station. system.   The upper station adds the lower station to the transmission destination of the control packet when the restoration notification is received from the lower station and the lower station is excluded from the transmission destination of the control packet. The wireless communication system according to 1. The control packet is periodically transmitted, and the serial packet can be transmitted in a period in which the control packet is not transmitted in the transmission period of the control packet. In each transmission period, the control packet is transmitted more than the serial packet. Sent first,
The wireless communication system according to claim 2, wherein transmission of the serial packet is started when a predetermined condition is satisfied. In the control packet, a maximum allowable time until returning to the predetermined wireless station via the slave station or the master station is set,
The wireless communication system according to claim 9, wherein a length of the transmission cycle is equal to or less than ½ of the maximum allowable time.   The predetermined condition is that the number of retransmissions of the control packet has reached a predetermined value, or that the control packet has returned to the predetermined wireless station via the slave station or the master station. Or the radio | wireless communications system of Claim 10.   The wireless communication system according to claim 11, wherein when the serial packet is not transmitted in the wireless communication system, the predetermined value is set to a maximum number of times that can be retransmitted in the transmission cycle.   The control packet is transmitted from the master station so as to return to the master station via all the slave stations and to minimize the number of the radio stations that pass through the control packet. The wireless communication system according to any one of claims 1 to 12. The control packet is retransmitted when it is determined that it has not been possible to return to the predetermined radio station via one or more radio stations,
The retransmission interval of the control packet is set to a length according to the number of the wireless stations that should transmit the control packet in the wireless communication system. Wireless communication system. The serial packets are transmitted at intervals,
The wireless communication system according to any one of claims 1 to 14, wherein a transmission interval of the serial packet is set to a length corresponding to a transmission rate of the traffic information. A communication control method in a wireless communication system comprising a master station that is a radio station for wirelessly transmitting traffic information and one or more slave stations,
The master station transmitting communication packets to the slave station at predetermined intervals;
The slave station transmitting the communication packet or another communication packet in response to receiving the communication packet;
The communication packet can store communication quality information of the wireless station and can pass through the wireless station, and a serial packet transmitted / received between the corresponding slave station and the parent station And a communication control method. A wireless communication system comprising a master station and a slave station that are wireless stations for wirelessly transmitting traffic information,
The traffic information includes contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the radio station,
The slave station is
A plurality of the contact information in time series, a contact processing unit for adding time information to each generated contact information;
A packet generation unit including the contact information to which the time information is added by the contact processing unit and the serial information in a separate packet;
A packet transmission unit that determines whether another wireless station is transmitting a wireless signal and that transmits the packet when it is determined that the other wireless station is not transmitting a wireless signal;
The main station acquires the contact information from the received plurality of packets, and rearranges the contact information in time series based on the time information added to the acquired contact information. system. The wireless communication system further includes a relay station that relays the packet between the master station and the slave station,
The wireless communication system according to claim 17, wherein the relay station preferentially relays the packet including the contact information generated within a predetermined time among the received packets based on the time information. . A communication control method in a wireless communication system including a master station and a slave station that are wireless stations for wirelessly transmitting traffic information,
The traffic information includes contact information based on a contact signal indicating whether or not a vehicle is detected, and serial information that is information different from the contact information and is information from a terminal connected to the radio station,
The slave station generates a plurality of the contact information in time series, and adds time information to each of the generated contact information;
The slave station includes the contact information to which the time information is added and the serial information included in a separate packet and transmitted to the master station.
In the step of transmitting the packet to the master station, the slave station determines whether another radio station is transmitting a radio signal and determines that the other radio station is not transmitting a radio signal. Send the packet in case
The communication control method further includes:
The main station includes acquiring the contact information from the received plurality of packets, and rearranging the contact information in chronological order based on the time information added to the acquired contact information. , Communication control method.

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