JP2019145993A - Communication system, roadside communication device, inter-road transfer method, and computer program - Google Patents

Abstract

To provide a communication system capable of preventing transfer of a packet without necessity of transferring.SOLUTION: In a communication system, a plurality of roadside communication devices 5 are provided in a plurality of controlled areas. The plurality of roadside communication devices 5 each comprise: a first determination part 13a that determines whether there is matching between an area code indicating a controlled area contained in a packet from another roadside communication device 5 to which the other roadside communication device 5 belongs, and the area code indicating the controlled area to which an own machine 5 belongs; and a communication control part 13c that determines whether an inter-road transfer of the packet is executed on the basis of a determination result of the first determination part 13a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a communication system, a roadside communication device, a road-to-road transfer method, and a computer program.

  In Patent Document 1, when a roadside communication device (base station) constituting an intelligent transport system (ITS: Intelligent Transport System) transfers a wireless packet to another roadside communication device by road-to-road communication, It is disclosed that a process for determining whether or not to transfer the wireless packet is performed.

JP 2014-78119 A

The roadside communication device of Patent Document 1 forms a network group by roadside communication together with other roadside communication devices. Each of the plurality of roadside communication devices constituting the network group is given identification information (ID) different from the IP address or the like set to identify the roadside communication device in the network group.
In the network, the determination as to whether or not to execute wireless packet transfer by road-to-road communication is performed based on the destination ID and the transmission source ID included in the wireless packet. The destination ID is information indicating the ID of the roadside communication device that is the destination of the wireless packet. The transmission source ID is information indicating the ID of the roadside communication device that is the transmission source of the wireless packet.

  The roadside communication device that has received the wireless packet determines whether or not the transmission source and the destination are the transmission source and the destination permitted to transfer the wireless packet based on the destination ID and the transmission source ID. Transfer determination processing is performed.

By the way, the roadside communication device may be disposed adjacent to a roadside communication device belonging to another network group other than the network group to which the own device belongs.
FIG. 13 is a diagram illustrating an example of a state in which two networks are adjacent to each other.
In FIG. 13, roadside communication devices 101, 102, 103 constitute a first network group. Moreover, the roadside communication devices 111, 112, and 113 constitute a second network group.

  In FIG. 13, the roadside communication device 101 of the first network group is permitted to communicate with the roadside communication device 102, and is not permitted to communicate with the roadside communication device 103. The roadside communication device 103 is allowed to communicate with the roadside communication device 102 and is not allowed to communicate with the roadside communication device 101. The roadside communication device 102 is allowed to communicate between the roadside communication devices 101 and 103.

In addition, the roadside communication devices 111, 112, and 113 of the second network group are set to the same communication configuration as the roadside communication devices 101, 102, and 103 of the first network group.
Furthermore, each roadside communication device is assumed to be in a positional relationship capable of receiving wireless packets transmitted in different groups.

Here, consider a case where the roadside communication device 111 of the second network group transmits a wireless packet toward the traffic signal 114 connected to the roadside communication device 113.
For example, if the identification information (ID) of the roadside communication device 111 of the second network group is “4”, the ID of the roadside communication device 112 is “5”, and the ID of the roadside communication device 113 is “6”, the roadside communication The wireless packet transmitted by the device 111 includes “4” as the transmission source ID and “6” as the destination ID.

  When the roadside communication device 112 receives the wireless packet transmitted by the roadside communication device 111, the roadside communication device 112 refers to the transmission source information and destination information of the received wireless packet. In this case, the transmission source information and the destination information indicate roadside communication devices that are permitted to transfer wireless packets in the roadside communication device 112. Therefore, the roadside communication device 112 transfers this wireless packet to the roadside communication device 113. The roadside communication device 113 that has received the transferred wireless packet gives the data included in the wireless packet to the traffic signal 114.

Further, it is assumed that the roadside communication device 102 of the first network group receives a wireless packet from the roadside communication device 111.
The wireless packet received by the roadside communication device 102 includes “4” that is an ID as transmission source information and “6” that is an ID as destination information.

At this time, the ID of the roadside communication device 101 of the first network group is “4”, the ID of the roadside communication device 102 is “5”, the ID of the roadside communication device 103 is “6”, and the roadside communication of the second network group Assuming that the IDs of the devices 111, 112, and 113 are set to overlap, the roadside communication device 102 has the roadside communication device 101 as the transmission source of the received wireless packet from the roadside communication device 111 and the destination as the roadside communication. It is determined that the machine 103.
Therefore, the roadside communication device 102 transfers the wireless packet to the roadside communication device 103 on the assumption that transfer of the wireless packet is permitted.

  The roadside communication device 103 that has received the transfer of the wireless packet from the roadside communication device 111 extracts the data included in the wireless packet, but the extracted data is not the data addressed to the traffic signal 104 connected to the own device 103. Discard the data.

  Thus, even if the roadside communication device transfers the wireless packet of the adjacent network group to the roadside communication device of its own network group, because it is incorrect data, it is eventually discarded, but it needs to be transferred. While transferring the wireless packet of the adjacent network group that is not present, the wireless packet of the own network group cannot be transmitted, and there is a possibility that transmission of data that is originally intended to be transmitted is delayed.

Such transfer of wireless packets that do not need to be transferred occurs when the same ID is given to the roadside communication devices in the adjacent network groups and the IDs overlap as in the above example.
In particular, at the boundary between two management areas such as prefectural boundaries, the system managers are different, so it is difficult to assign an ID to each roadside communication device so as not to overlap between network groups.
For this reason, there is a high possibility that transfer of wireless packets that do not need to be transferred due to overlapping IDs occurs at the boundary between two management areas such as prefectural boundaries.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of preventing transfer of a packet that does not need to be transferred.

  A communication system according to an embodiment is a communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas, and the plurality of roadside communication devices are included in packets from other roadside communication devices. A first determination unit for determining whether or not an area code indicating a management area to which another roadside communication device belongs and an area code indicating a management area to which the own roadside communication device belongs; and a determination result of the first determination unit And a communication control unit for determining whether or not to perform the inter-road transfer of the packet.

  A communication system according to another embodiment is a communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas, and each of the plurality of roadside communication devices has a unique identification for each of the plurality of management areas. Information is provided, and the plurality of roadside communication devices, based on the identification information indicating the other roadside communication device included in the packet from the other roadside communication device, the other roadside communication device is the source of the packet A determination unit that determines whether or not the roadside communication device is permitted as a communication control unit that determines whether or not to perform inter-road transfer of the packet based on a determination result of the determination unit; Prepare.

  A roadside communication device according to another embodiment is a roadside communication device provided in any of a plurality of management areas, and a management area to which the other roadside communication apparatus included in a packet from the other roadside communication apparatus belongs. A first determination unit that determines whether or not an area code that is indicated is the same as an area code that indicates a management area to which the local communication device belongs, and a route between the packets based on a determination result of the first determination unit A communication control unit that determines whether or not to execute the transfer.

  The road-to-road transfer method according to another embodiment is a method in which a roadside communication device provided in any of a plurality of management areas transfers a packet from another roadside communication device between roads, A first step for determining whether or not an area code indicating a management area to which the other roadside communication device to which the other roadside communication device belongs included is the same as an area code indicating the management area to which the own roadside communication device belongs, and the first step And a second step of determining whether or not to execute the inter-road transfer of the packet based on the determination result.

  Furthermore, a computer program according to another embodiment is a computer program for causing a roadside communication device provided in any of a plurality of management areas to execute a process of transferring a packet from another roadside communication device between roads. The computer program determines whether or not the area code indicating the management area to which the other roadside communication device included in the packet belongs and the area code indicating the management area to which the roadside communication device belongs are the same. And a second step of determining whether or not to perform inter-route transfer of the packet based on a determination result of the first step.

  According to the present invention, it is possible to prevent transfer of a packet that does not need to be transferred.

FIG. 1 is a diagram illustrating a traffic control system as an example of a communication system according to the first embodiment. FIG. 2 is a schematic diagram showing an example in which roadside communication devices and traffic terminals of a traffic control system are arranged on a road. FIG. 3 is a block diagram illustrating a configuration example of a roadside communication device. FIG. 4A is a diagram illustrating an example of an IP forwarding table. FIG. 4B is a diagram illustrating an example of a road transfer table. FIG. 5 is a diagram illustrating a structure of a wireless packet transmitted / received by a roadside communication device. FIG. 6 is a flowchart illustrating an example of a transfer determination process for determining whether or not to perform a transfer of a wireless packet between roads performed by a roadside communication device. FIG. 7 is a diagram illustrating a case where roadside communication devices belonging to different network groups are adjacent to each other across the prefectural border. FIG. 8 is a diagram illustrating an example of a road transfer table included in the roadside communication device. FIG. 9 is a block diagram illustrating a configuration of a roadside communication device according to the second embodiment. FIG. 10 is a flowchart illustrating a transfer determination process for determining whether or not to execute the inter-road transfer of a wireless packet, which is performed by the roadside communication device according to the second embodiment. FIG. 11 is a diagram illustrating a case where roadside communication devices belonging to different network groups are adjacent to each other across a prefectural border. FIG. 12 is a diagram illustrating an example of a wireless device ID table included in a roadside communication device. FIG. 13 is a diagram illustrating an example of a state in which two networks are adjacent to each other.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[Outline of Embodiment]
(1) A communication system according to an embodiment is a communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas, and the plurality of roadside communication devices receive packets from other roadside communication devices. A first determination unit for determining whether or not an area code indicating a management area to which the other roadside communication device included belongs is the same as an area code indicating the management area to which the own roadside communication device belongs; and the first determination unit And a communication control unit that determines whether or not to perform the inter-road transfer of the packet based on the determination result.

  According to the communication system having the above configuration, it is possible to determine whether or not the management area to which the other roadside communication device belongs and the management area to which the own roadside communication device belongs are the same. If it is determined that the management area of the own device is not the same, it can be determined that the packet is not transferred between the roads. As a result, it is possible to prevent packets from other roadside communication devices having different management areas that do not need to be transferred from being transferred.

(2) In the communication system, the plurality of roadside communication devices are provided with first identification information for identifying each roadside communication device, and the packet includes first identification information indicating the other roadside communication device. A second determination unit that determines whether or not the other roadside communication device is a roadside communication device that is permitted as a transmission source of the packet based on first identification information indicating the other roadside communication device. The communication control unit may determine whether to execute the inter-road transfer of the packet based on the determination result of the first determination unit and the determination result of the second determination unit. preferable.
In this case, in addition to the determination by the first determination unit, by determining whether another roadside communication device is a permitted roadside communication device as a packet transmission source, packets that do not need to be transferred are transferred. Can be more effectively prevented.

(3) In the communication system, the second determination unit includes a table in which first identification information indicating a roadside communication device permitted as a transmission source of the packet is registered, and refers to the table. It is preferable to determine whether or not the other roadside communication device is a roadside communication device that is permitted as a transmission source of the packet. In this case, the second determination unit refers to the table so that the other roadside communication device Can be determined.

(4) In the communication system, the communication control unit may perform determination based on the determination result of the second determination unit after performing determination based on the determination result of the first determination unit.
In this case, the processing load can be reduced by executing the determination by the management area including the plurality of roadside communication devices first, rather than the determination by the first identification information given to each roadside communication device.

(5) In the communication system, at least some of the plurality of roadside communication devices form a network group capable of communicating with each other in the same management area, and the other roadside communication devices included in the packet. May include information for identifying a network group to which the other roadside communication device belongs.
In this case, the second determination unit can determine whether or not the network group to which the other roadside communication device belongs and the network group to which the own device belongs are the same based on the information for identifying the network group. . Therefore, it is possible to prevent transfer of packets that are transmitted from roadside communication devices belonging to different network groups in the same management area and do not need to be transferred.

(6) Moreover, in the communication system, the plurality of roadside communication devices are provided with second identification information that is different from the first identification information and is unique for each of the plurality of management areas. The packet includes second identification information indicating the other roadside communication device, and the other roadside communication device is permitted as a transmission source of the packet based on the second identification information indicating the other roadside communication device. A third determination unit that determines whether or not the roadside communication device is, the communication control unit based on at least the determination result of the first determination unit and the determination result of the third determination unit, It is preferable to determine whether or not to execute packet transfer between routes.
In this case, based on the second identification information unique to a plurality of management areas, it is possible to determine whether another roadside communication device is a roadside communication device permitted as a packet transmission source. The determination result of whether or not the management area of the machine is the same as the management area of the own machine can be used, and it is possible to more effectively prevent packets that do not need to be transferred.

(7) Further, the communication system according to another embodiment is a communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas, and the plurality of roadside communication devices include the plurality of management areas. Unique identification information is given on a unit basis, and the plurality of roadside communication devices are connected to the other roadside communication devices based on identification information indicating the other roadside communication devices included in a packet from another roadside communication device. A determination unit that determines whether or not the packet transmission source is permitted as a transmission source of the packet, and communication that determines whether or not to perform the inter-road transfer of the packet based on a determination result of the determination unit A control unit.

  According to the communication system having the above configuration, since it is determined whether another roadside communication device is permitted as a packet transmission source based on the second identification information unique to a plurality of management areas. If other roadside communication devices belong to the same management area, it is possible to prevent transfer of packets that do not need to be transferred.

(8) Moreover, in the communication system, the plurality of management areas are preferably prefectures.

(9) A roadside communication device according to another embodiment is a roadside communication device provided in any of a plurality of management areas, and the other roadside communication device included in a packet from another roadside communication device belongs to the roadside communication device. Based on the determination result of the first determination unit, a first determination unit that determines whether the area code indicating the management area and the area code indicating the management area to which the local roadside communication device belongs are the same. And a communication control unit that determines whether or not to execute transfer between roads.

(10) A road-to-road transfer method according to another embodiment is a method in which a roadside communication device provided in any of a plurality of management areas transfers a packet from another roadside communication device between roads. A first step of determining whether or not an area code indicating a management area to which the other roadside communication device to which the other roadside communication device belongs included in the packet is the same as an area code indicating the management area to which the own roadside communication device belongs; And a second step of determining whether or not to execute the inter-road transfer of the packet based on the determination result in one step.

(11) Furthermore, a computer program according to another embodiment causes a computer to execute a process in which a roadside communication device provided in any of a plurality of management areas transfers a packet from another roadside communication device between roads. Whether the area code indicating the management area to which the other roadside communication device included in the packet belongs and the area code indicating the management area to which the roadside communication device belongs are the same. A computer program that causes a computer to execute a first step for determining whether or not a second step for determining whether or not to perform inter-route transfer of the packet based on a determination result in the first step. is there.

[Details of the embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings.
Note that at least a part of each embodiment described below may be arbitrarily combined.
[About overall system configuration]
FIG. 1 is a diagram illustrating a traffic control system as an example of a communication system according to the first embodiment.
The traffic control system 1 includes a central device 2 and a plurality of traffic terminals 6 managed (controlled) by the central device 2.

  The central apparatus 2 is connected to one or a plurality of routers 4 via a network 3. A plurality of traffic terminals 6 are connected to the router 4 via a communication path including a wired communication path 8 and a wireless communication path. The plurality of traffic terminals 6 include a traffic signal controller, an optical beacon, and the like.

  The traffic control system 1 includes a plurality of roadside communication devices 5 that are wireless devices for forming a wireless communication path between the router 4 and the traffic terminal 6.

  The plurality of roadside communication devices 5 include a roadside communication device 5 connected to the router 4 and a roadside communication device 5 connected to the traffic terminal 6. A router 4 may be further interposed between the roadside communication device 5 and the traffic terminal 6.

The plurality of roadside communication devices 5 have a function of transmitting a wireless packet (a road-to-vehicle communication function) with a mobile station such as an in-vehicle communication device, and constitute a base station for the mobile station.
As for road-to-vehicle communication, the Japan Radio Industry Association, “700MHz Band Intelligent Transport System ARIB-STD T109 Version 1.0”, ITS Information Communication System Promotion Conference, “700MHz Band Intelligent Transport System Extended Function Guidelines ITS FORUM RC-010 1.0 edition ".

Here, since the wireless packets transmitted from the plurality of roadside communication devices 5 are broadcasted, the wireless packets can be received not only by the mobile station, but other than the roadside communication devices 5 that transmitted the wireless packets. Other roadside communication devices 5 can also receive wireless packets. That is, the plurality of roadside communication devices 5 can communicate with each other by wireless packets (inter-road communication: inter-base station communication).
In the present embodiment, communication (roadside communication) between the roadside communication devices 5 that are base stations is used for communication between the router 4 and the traffic terminal 6.

FIG. 2 is a schematic diagram showing an example in which the roadside communication device 5 and the traffic terminal 6 of the traffic control system 1 are arranged on the road.
The traffic terminal 6 is installed near an intersection or near a road other than the intersection. A roadside communication device 5 is connected to each traffic terminal 6 via a communication line. The roadside communication device 5 is installed in the vicinity of the traffic terminal 6. A router 4 is connected to a specific traffic terminal 6 (a terminal installed near a relatively large intersection) among the plurality of traffic terminals 6 via a communication line.

The router 4 connected to the central device 2 via the network 3 can distribute information (data) transmitted from the central device 2 to the traffic terminal 6 connected to the router 4. Further, the router 4 can give the information transmitted from the central device 2 to the roadside communication device 5 connected to the router 4. The roadside communication device 5 connected to the router 4 includes information (data) transmitted from the central device 2 in a wireless packet and wirelessly transmits (broadcasts) it to other roadside communication devices 5. Thereby, the information transmitted from the central apparatus 2 is given to the traffic terminal 6 connected to the other roadside communication device 5.
Conversely, the traffic terminal 6 connected to another roadside communication device 5 gives the information (data) generated by the traffic terminal 6 to the other roadside communication device 5. The other roadside communication device 5 includes the information generated by the traffic terminal 6 in the wireless packet and transmits it to the roadside communication device 5 connected to the router 4. The router 4 can acquire information transmitted from the traffic terminal 6 via wireless communication and transmit the information to the central device 2. Thus, the traffic terminal 6 connected to the other roadside communication device 5 sends the information (data) generated by the traffic terminal 6 to the roadside communication device 5 to transmit the information to the central device 2. can do.
The roadside communication device 5 as a base station also transmits information to the in-vehicle communication device 7 as a mobile station.

  In this way, even for the traffic terminal 6 that is not connected to the router 4 by a wired communication line, the router 4 and the central device 2 are utilized by using the wireless communication (inter-road communication) between the roadside communication devices 5. Can communicate with.

Each roadside communication device 5 shown in FIG. 2 forms a network group by performing inter-road communication with each other.
In order to perform roadside communication with each other, each roadside communication device 5 is assigned a communication device ID (first identification information: base station ID) for identifying each roadside communication device 5. This communication device ID is used as information for indicating the generation source, transmission source, destination, and the like of the wireless packet when each roadside communication device 5 transmits the wireless packet. This communication device ID is identification information different from the IP address. In the present embodiment, the communication device ID is, for example, an integer arranged in order from “1”.

For example, communication device IDs 1 to 5 are assigned to the five roadside communication devices 5 in FIG.
In FIG. 2, the roadside communication device 5 with the communication device ID 1 is permitted to perform roadside communication between the roadside communication devices 5 with the communication device IDs 2, 3, and 4.
Further, the roadside communication device 5 with the communication device IDs 2 and 3 is permitted to communicate with the roadside communication device 5 with the communication device ID 1.
The roadside communication device 5 with the communication device ID 4 is permitted to communicate with the roadside communication device 5 with the communication device IDs 1 and 5.
The roadside communication device 5 with the communication device ID 5 is permitted to communicate with the roadside communication device 5 with the communication device ID 4.

Each roadside communication device 5 has a table (road transfer table) in which information for determining whether wireless packets can be transferred by road-to-road communication is registered. Each roadside communication device 5 refers to this table to determine whether the wireless packet can be transferred between roads.
Each roadside communication device 5 can perform roadside communication with the permitted roadside communication device 5 by transferring the wireless packet between the roads according to the table.

In this way, the five roadside communication devices 5 shown in FIG. 2 constitute a network that can perform road-to-road transfer with each other.
In FIG. 2, one network group is shown, but the roadside communication devices 5 belonging to other network groups may be arranged at positions adjacent to the roadside communication devices 5.

[Configuration of roadside communication device]
FIG. 3 is a block diagram illustrating a configuration example of the roadside communication device 5.
As shown in FIG. 3, the roadside communication device 5 includes a wireless communication unit 10 that transmits and receives wireless signals, a wired communication unit 11 that is connected to the router 4 or the traffic terminal 6 and performs wired communication, and a processing device 12. It has.

The processing device 12 includes a computer including a processing unit 13 including a CPU (Central Processing Unit) and a storage unit 14 including a hard disk.
The processing unit 13 receives data generated by the router 4 or the traffic terminal 6 to generate a wireless packet, and performs processing for wirelessly transmitting the wireless packet generated by the wireless communication unit 10. In addition, the processing unit 13 performs a process of giving the data included in the wireless packet received from the other roadside communication device 5 received by the wireless communication unit 10 to the traffic terminal 6. Further, the processing unit 13 has a function of transferring a wireless packet from another roadside communication device 5 to another roadside communication device 5 by roadside communication (interroad transfer).

Moreover, the process part 13 is provided with the 1st determination part 13a, the 2nd determination part 13b, and the communication control part 13c as a function part which performs the process regarding transfer between roads.
The functions of these parts will be described later.

The storage unit 14 stores a computer program and the like for execution by the processing unit 13, and the above-described various processes are realized by the processing unit 13 reading and executing the computer program.
The storage unit 14 also stores an IP transfer table 16 and a route transfer table 17 used for various processes performed by the processing unit 13.

FIG. 4A is a diagram illustrating an example of the IP forwarding table 16. 4A shows the IP transfer table 16 of the roadside communication device 5 to which “1” is assigned as the communication device ID in FIG.
The IP forwarding table 16 is referred to when the roadside communication device 5 that has received data generated by the router 4 or the traffic terminal 6 generates a wireless packet.
In the IP forwarding table 16, a destination IP address and a destination communication device ID are registered in association with each other.

The destination IP address is an IP address that is included in the data generated by the router 4 or the traffic terminal 6 and indicates the destination of the data. Therefore, the destination IP address is one of IP addresses assigned to the router 4 and the traffic terminal 6 included in the network group.
The destination communication device ID is a communication device ID indicating the roadside communication device 5 to which the destination router 4 or the traffic terminal 6 indicated by the destination IP address is connected. That is, the destination communication device ID is a communication device ID indicating the roadside communication device 5 that is the destination of the wireless packet. Therefore, the destination communication device ID is one of the communication device IDs assigned to each of the other roadside communication devices 5 included in the network group. The destination communication device ID is included in the wireless packet by the roadside communication device 5 when generating the wireless packet.

The IP forwarding table 16 includes a destination IP address and a communication device ID (destination communication device ID) of the roadside communication device 5 to be a destination when data is transmitted to the router 4 or the traffic terminal 6 indicated by the destination IP address. Are registered in association with each other.
When the roadside communication device 5 receives the data from the router 4 or the traffic terminal 6 and generates a wireless packet, the roadside communication device 5 refers to the IP forwarding table 16 and acquires the corresponding destination communication device ID.

FIG. 4B is a diagram illustrating an example of the road transfer table 17. FIG. 4B shows the road transfer table 17 of the roadside communication device 5 to which “1” is assigned as the communication device ID in FIG.
The road transfer table 17 is referred to when determining whether or not to transfer a wireless packet from another roadside communication device 5.
In the route transfer table 17, a source communication device ID and a destination communication device ID are registered.

The transmission source communication device ID is a communication device ID that is included in the wireless packet and indicates the roadside communication device 5 that is the transmission source of the wireless packet.
Further, as described above, the destination communication device ID is also included in the wireless packet, and is a communication device ID indicating the roadside communication device that is the destination of the wireless packet.

  In the route transfer table 17, a combination of a source communication device ID and a destination communication device ID for which the roadside communication device 5 having the route transfer table 17 is permitted to transfer wireless packets between routes is registered. ing.

The roadside communication device 5 having the road transfer table 17 shown in FIG. 4B (the roadside communication device 5 with communication device ID = “1” in FIG. 2) has a communication device ID of 2, 3, and 4 respectively. And inter-road communication is permitted. Therefore, 2, 3, and 4 are registered as communication device IDs in the transmission source communication device ID of the route transfer table 17, and the communication device IDs according to the network route are stored in the destination communication device ID. It is registered. That is, in the road transfer table 17, a source communication device ID that is information indicating the roadside communication device 5 permitted as a packet transmission source is registered.
The determination of whether or not to transfer a wireless packet using the road transfer table 17 will be described in detail later.

[Wireless packet structure]
FIG. 5 is a diagram illustrating a structure of a wireless packet transmitted / received by the roadside communication device 5.
In FIG. 5, the radio packet has, from the top, each area of radio communication control information, IRC header (inter-road communication control information), data body, and FCS (Frame Check Sequence).
The wireless communication control information is an area for control information related to wireless communication of wireless packets.

  In the wireless packet, the IRC header and the data body area are areas in which application data as a wireless packet is stored. That is, the IRC header and the data body are application data as radio packets.

When the roadside communication device 5 transmits data for the in-vehicle communication device 7 as a mobile station (data for road-to-vehicle communication), application data for the in-vehicle communication device 7 is stored in the area where the application data is stored. Stored.
On the other hand, when the roadside communication device 5 transmits a wireless packet to the other roadside communication device 5 in order to transmit information to the traffic terminal 6 connected to the other roadside communication device 5, A frame composed of an IRC header and a data body is stored in an area where application data as a packet is stored. That is, FIG. 5 shows a wireless packet for road-to-road communication.

The roadside communication device 5 to which the data generated by the router 4 or the traffic terminal 6 is given generates application data as a radio packet by using the given data as a data body and adding an IRC header.
Further, the roadside communication device 5 generates a wireless packet by adding wireless communication control information to the application data.

  The data generated by the router 4 and the traffic terminal 6 includes a header part and a data part. The data generated by the router 4 and the traffic terminal 6 is a communication packet transmitted and received between the central device 2, the router 4, and the traffic terminal 6, and the header portion includes a transmission source IP address of the communication packet. And a destination IP address and the like.

The IRC header is generated by the roadside communication device 5 when a wireless packet is generated. The IRC header is used for processing performed by the roadside communication device 5 that has received the wireless packet.
As shown in FIG. 5, the IRC header includes communication type information 21, a prefecture code 22, a wireless device ID 23, a transmission source communication device ID 24, a destination communication device ID 25, and a generation source communication device ID 26.

  The communication type information 21 is identification information indicating whether the wireless packet corresponds to “road-to-vehicle communication”, “vehicle-to-vehicle communication”, or “road-to-road communication”. For example, in the case of a wireless packet exchanged between the roadside communication device 5 connected to the router 4 and the roadside communication device 5 connected to the traffic terminal 6, the communication type information 21 indicates “inter-road communication”. It is set as follows. “Vehicle-to-vehicle communication” refers to communication between mobile stations (vehicle communication devices 7).

The prefecture code 22 is information (area code) indicating a prefecture as a management area to which the roadside communication device 5 that is the transmission source of the wireless packet belongs.
In the present embodiment, a management area for managing each roadside communication device 5 is set for each prefecture. A management area of each roadside communication device 5 is determined according to the installation location. Each roadside communication device 5 is managed by a manager of the prefecture to which the installation location belongs. For example, if the installation location of the roadside communication device 5 is A prefecture, the roadside communication device 5 is managed by an administrator of A prefecture. Each roadside communication device 5 stores a prefecture code indicating the prefecture to which the own device 5 belongs.

  The prefecture code included in the IRC header indicates the prefecture that manages the transmission-side roadside communication device 5 that has transmitted the wireless packet.

  The wireless device ID 23 is information indicating the management number of the transmission-side roadside communication device 5 that has transmitted the wireless packet, and has a function as identification information (second identification information). As the wireless device ID 23, a unique number is assigned to each roadside communication device 5 in units of prefectures (management area units).

As described above, the transmission source communication device ID 24 is a communication device ID that indicates the roadside communication device 5 that is the transmission source of the wireless packet.
As described above, the destination communication device ID 25 is a communication device ID indicating the roadside communication device 5 that is the destination of the wireless packet.
The generation source communication device ID 26 is a communication device ID indicating the roadside communication device 5 that has generated the wireless packet.

[Transfer determination processing]
FIG. 6 is a flowchart showing an example of a transfer determination process for determining whether or not to execute the transfer of a wireless packet between roads performed by the roadside communication device 5.
First, the roadside communication device 5 determines whether or not a wireless packet has been received (step S1). If it is determined that the wireless packet has not been received, the roadside communication device 5 returns to step S1 again. Therefore, the roadside communication device 5 repeats step S1 until it is determined that a wireless packet has been received.

If it is determined in step S1 that the wireless packet has been received, the roadside communication device 5 proceeds to step S2, reads the communication type information 21 included in the IRC header of the wireless packet, and the wireless packet is “inter-road communication”. It is determined whether the packet is a wireless packet (step S2).
If it is determined in step S2 that the wireless packet is not “road-to-road communication”, the communication control unit 13c of the roadside communication device 5 proceeds to step S3, and the wireless packet is sent to “road-to-vehicle communication” or “vehicle-to-vehicle communication”. Appropriate processing is performed as a wireless packet (step S3).

  If it is determined in step S2 that the radio packet is “inter-road communication”, the first determination unit 13a of the roadside communication device 5 proceeds to step S4, reads the prefecture code included in the IRC header of the radio packet, It is determined whether or not the prefecture code and the prefecture code stored in the own machine 5 are the same (step S4).

  If it is determined in step S4 that the prefecture code included in the wireless packet is not the same as the prefecture code stored in the own device 5, the communication control unit 13c of the roadside communication device 5 proceeds to step S5 and discards the wireless packet (step S5), the process ends.

On the other hand, if it is determined in step S4 that the prefecture code of the wireless packet is the same as the prefecture code of the own device 5, the roadside communication device 5 proceeds to step S6.
In step S6, the second determination unit 13b of the roadside communication device 5 reads the source communication device ID and the destination communication device ID included in the IRC header of the wireless packet, and refers to the road transfer table 17 to check the wireless packet. It is determined whether or not the combination of the source communication device ID and the destination communication device ID included in is registered in the route transfer table 17 (step S6). As a result, the second determination unit 13b determines whether the roadside communication device 5 that is the transmission source of the wireless packet is permitted as the transmission source of the wireless packet based on the transmission source communication device ID of the wireless packet. Determine whether.

  If it is determined in step S6 that the combination of the source communication device ID and the destination communication device ID included in the wireless packet is not registered in the road transfer table 17, the communication control unit 13c of the roadside communication device 5 performs step S5. , The wireless packet is discarded (step S5), and the process ends.

  On the other hand, if it is determined in step S6 that the combination of the source communication device ID and the destination communication device ID included in the wireless packet is registered in the road transfer table 17, the communication control unit 13c of the roadside communication device 5 It progresses to step S7 and it is determined whether a radio | wireless packet is addressed to the own machine 5 (step S7).

If it is determined in step S7 that the wireless packet is addressed to the own device 5, the communication control unit 13c of the roadside communication device 5 proceeds to step S3 and appropriately processes the wireless packet as a wireless packet addressed to the own device 5. (Step S3), the process ends.
If it is determined in step S7 that the wireless packet is not addressed to the own device 5, the roadside communication device 5 proceeds to step S8.
In step S8, the communication control unit 13c of the roadside communication device 5 determines to transfer the wireless packet by the road-to-road communication (step S8), and the process ends.

  As described above, the communication control unit 13c of the roadside communication device 5 determines the wireless packet based on the determination result of the first determination unit 13a (step S4) and the determination result of the second determination unit 13b (step S6). It is determined whether the transfer between the roads or the discarding of the wireless packet is executed. That is, the communication control unit 13c determines whether or not to perform wireless packet transfer between roads based on the determination result of the first determination unit 13a and the determination result of the second determination unit 13b.

FIG. 7 is a diagram illustrating a case where the roadside communication devices 5 belonging to different network groups are adjacent to each other across the prefectural border.
In FIG. 7, the roadside communication device 5A1 and the roadside communication device 5A2 and the roadside communication device 5A2 and the roadside communication device 5A3 can communicate with each other between the roadside communication devices 5A1, 5A2, and 5A3. Constitutes a network group (group G1).

  In FIG. 7, the roadside communication device 5B1 and the roadside communication device 5B2 and the roadside communication device 5B2 and the roadside communication device 5B3 can communicate with each other between the roadside communication devices 5B1 and 5B2. , 5B3 constitute a network group (group G2).

  Further, in FIG. 7, the roadside communication device 5A4 and the roadside communication device 5A5 and the roadside communication device 5A5 and the roadside communication device 5A6 can communicate with each other between the roadside communication devices 5A4 and 5A5. , 5A6 constitute a network group (group G3).

The roadside communication devices 5 belonging to the group G1 and the group G3 are installed in the A prefecture. Therefore, the roadside communication devices 5 belonging to the group G1 and the group G3 belong to the A prefecture, and “A prefecture” is stored as the prefecture code.
The roadside communication device 5 belonging to the group G2 is installed in the B prefecture. Therefore, the roadside communication device 5 belonging to the group G2 belongs to the B prefecture, and stores “B prefecture” as the prefecture code.
Furthermore, the roadside communication device 5 belonging to the group G1 and the roadside communication device 5 belonging to the group G2 are arranged adjacent to each other across the prefectural border between the A prefecture and the B prefecture.
In FIG. 7, it is assumed that each roadside communication device 5 is installed at a position where radio packets can be received between roadside communication devices 5 belonging to adjacent groups.

In the group G1, the roadside communication device 5A1 is assigned “1” as the communication device ID, the roadside communication device 5A2 is assigned “4” as the communication device ID, and the roadside communication device 5A3 is assigned “5” as the communication device ID. Is given.
In the group G2, the roadside communication device 5B1 is assigned “1” as the communication device ID, the roadside communication device 5B2 is assigned “4” as the communication device ID, and the roadside communication device 5B3 is assigned the communication device ID. “5” is assigned.
Further, in the group G3, “11” is assigned as the communication device ID to the roadside communication device 5A4, “14” is assigned as the communication device ID to the roadside communication device 5A5, and the communication device ID is assigned to the roadside communication device 5A6. “15” is assigned.

[Route transfer within the same network group]
Here, in FIG. 7, when the traffic terminal 6a connected to the roadside communication device 5B1 of the group G2 transmits data to the traffic terminal 6b connected to the roadside communication device 5B3 of the same group G2. Will be described.

First, the traffic terminal 6a connected to the roadside communication device 5B1 gives the data addressed to the traffic terminal 6b to the roadside communication device 5B1.
The roadside communication device 5B1 that has received this data reads the destination IP address included in the data and refers to the transfer table 16 to acquire the destination communication device ID corresponding to the destination IP address. In this case, the roadside communication device 5B1 acquires “5” as the destination IP address.
Further, the roadside communication device 5B1 has “roadside communication” as the communication type information 21, “B prefecture” as the prefecture code 22, “1” as the source communication device ID24, “5” as the destination communication device ID25, and source communication. An IRC header storing “1” as the machine ID 26 is added to the data to generate a radio packet.

As shown in FIG. 7, the roadside communication device 5B1 wirelessly transmits the wireless packet P1 described above.
The roadside communication device 5B2 of the group G2 that has received the wireless packet P1 executes processing according to the transfer determination processing shown in FIG.
The roadside communication device 5B2 reads various information included in the IRC header of the wireless packet P1. At this time, since the communication type information 21 of the wireless packet P1 is “inter-road communication” (step S2 in FIG. 6), the first determination unit 13a of the roadside communication device 5B2 determines the prefecture code of the wireless packet P1 and its own device. It is determined whether or not the prefecture code is the same (step S4 in FIG. 6).

  The prefecture code 22 of the wireless packet P1 is “B prefecture”, and the roadside communication device 5B2 stores “B prefecture” as the prefecture code. Are determined to be the same.

  Next, the second determination unit 13b of the roadside communication device 5B2 reads the transmission source communication device ID and the destination communication device ID of the wireless packet and refers to the road transfer table 17 to transmit the transmission device communication device ID of the wireless packet P1. Then, it is determined whether or not the combination of the destination communication device ID is registered in the route transfer table 17 (step S6 in FIG. 6).

FIG. 8 is a diagram illustrating an example of a road transfer table 17 included in the roadside communication device 5B2.
Since the roadside communication device 5B2 is capable of inter-road communication between the roadside communication device 5B1 and the roadside communication device 5B3, the transmission source communication device ID column of the road transfer table 17 includes the roadside communication device 5B1 and the roadside communication device. The communication device IDs “1” and “5” assigned to the communication device 5B3 are registered. A destination communication device ID is also registered corresponding to the transmission source communication device ID.

The same combination as the combination of the source communication device ID and the destination communication device ID of the wireless packet P1 (the transmission source communication device ID is “1” and the destination communication device ID is “5”) is registered in the route transfer table 17. Has been.
Therefore, the second determination unit 13b that refers to the route transfer table 17 determines that the combination of the source communication device ID and the destination communication device ID of the wireless packet P1 is registered in the route transfer table 17.

Further, the roadside communication device 5B2 determines that the wireless packet is not addressed to the own device 5B2 from the destination communication device ID (step S7 in FIG. 6), and the communication control unit 13c of the roadside communication device 5B2 sends the wireless packet P1 to the route. It is determined that the data is to be transferred (step S8 in FIG. 6), and the process ends.
Thereafter, the roadside communication device 5B2 transfers the wireless packet P1 between roads according to this determination.

[Route transfer of wireless packets from network groups in other prefectures]
The wireless packet P1 wirelessly transmitted by the roadside communication device 5B1 in FIG. 7 may reach the roadside communication device 5A2 of the adjacent group G1.
In FIG. 7, “1” is assigned as the communication device ID to the roadside communication device 5A1 in the group G1, “4” is assigned as the communication device ID to the roadside communication device 5A2, and the communication device ID is assigned to the roadside communication device 5A3. “5” is assigned.
That is, the communication device ID assigned to the roadside communication devices 5A1, 5A2, and 5A3 included in the group G1 and the communication device assigned to the roadside communication devices 5B1, 5B2, and 5B3 included in the group G2 adjacent to the group G1. The ID is set redundantly.

In this case, the roadside communication device 5A2 of the group G1 has a road transfer table 17 including the same contents as the roadside communication device 5B2 of the group G2.
For this reason, for example, if the roadside communication device 5A2 of the group G1 receives the wireless packet P1 from the roadside communication device 5B1 of the group G2, the roadside communication device 5A2 receives the transmission source communication device ID and the received wireless packet P1. From the combination of the destination communication device IDs, there is a possibility that the wireless packet P1 is mistakenly recognized as a wireless packet from the roadside communication device 5A1 of the same group G1 and transferred between the roads.

The roadside communication device 5A2 originally does not need to process the wireless packet P1 of the group G2 belonging to another prefecture.
In this regard, the present embodiment is configured to prevent transfer of wireless packets transmitted from network groups belonging to other prefectures.
Hereinafter, a case where the wireless packet P1 is received by the roadside communication device 5A2 of the group G1 will be described.

The roadside communication device 5A2 of the group G1 that has received the wireless packet P1 executes processing according to the transfer determination processing shown in FIG.
The roadside communication device 5A2 reads various information included in the IRC header of the wireless packet P1. Since the communication type information 21 of the wireless packet P1 is “inter-road communication” (step S2 in FIG. 6), the first determination unit 13a of the roadside communication device 5A2 determines the state code of the wireless packet P1, the state code of its own device, Are the same (step S4 in FIG. 6).

Since the prefecture code 22 of the wireless packet P1 is “B prefecture” and the roadside communication device 5A2 stores “A prefecture” as the prefecture code, the first determination unit 13a includes the prefecture code of the wireless packet P1 and the prefecture code of its own device. Are not the same.
Therefore, the communication control unit 13c of the roadside communication device 5A2 discards the wireless packet P1 (step S5 in FIG. 6) and ends the process.

  As described above, according to the present embodiment, by comparing the prefecture code of the received wireless packet with the prefecture code of the own device 5, the state (control area) of the other roadside communication device 5 that has transmitted the wireless packet It can be determined whether or not the prefecture (management area) of the own device 5 is the same. Further, if it is determined that the prefecture of the other roadside communication device 5 is not the same as the prefecture of the own device 5, the wireless packet is discarded and the wireless packet is not transferred between the roads. As a result, it is possible to prevent transfer of wireless packets from other roadside communication devices with different prefectures that do not need to be transferred.

  In the present embodiment, since it is determined whether or not to perform the inter-road transfer of the wireless packet based on the determination result by the first determination unit 13a and the determination result by the second determination unit 13b. It is possible to more effectively prevent packets that do not need to be transferred.

[Route transfer of wireless packets from different network groups in the same prefecture]
Next, in FIG. 7, the traffic terminal 6c connected to the roadside communication device 5A4 of the group G3 generates data addressed to the traffic terminal 6d connected to the roadside communication device 5A6 of the same group G3, A case where the wireless packet P2 including the data is transmitted by the roadside communication device 5A4 will be described.

The roadside communication device 5A2 does not need to process the wireless packet P2 transmitted from the roadside communication device 5A4 of a different network group even within the same prefecture.
In this regard, the present embodiment is configured to prevent transfer of wireless packets transmitted from different network groups.

  Here, in this embodiment, information for identifying a network group is included in the communication device ID given to the roadside communication device 5, and when the network groups are adjacent to each other in the same prefecture, It is possible to identify whether the roadside communication device 5 belongs to the network group.

In FIG. 7, for example, in prefecture A, communication device IDs “1” to “9” are assigned to the roadside communication devices 5 of group G1, and communication device IDs “10” to “19” are assigned to the roadside of group G3. The communication device ID is assigned to the communication device 5 and the communication device IDs “20” to “29” are assigned to the roadside communication devices 5 of another group in A prefecture.
In other words, in this embodiment, the communication device ID is an integer that is arranged in order from “1”. By dividing these into 10 units, information for identifying the network group is given to the communication device ID. doing.
Thus, by classifying the communication device ID based on a predetermined rule, information for identifying the network group is given to the communication device ID.

  In FIG. 7, as described above, the roadside communication device 5A4 in the group G3 is assigned “11” as the communication device ID, and the roadside communication device 5A5 is assigned “14” as the communication device ID. 5A6 is assigned “15” as the communication device ID.

  In this case, the roadside communication device 5A4 of the group G3 has “roadside communication” as the communication type information 21, “A prefecture” as the prefecture code 22, “11” as the source communication device ID24, and “15” as the destination communication device ID25. Then, an IRC header storing “11” as the generation source communication device ID 26 is added to the data to generate a wireless packet.

As shown in FIG. 7, the roadside communication device 5A4 wirelessly transmits the wireless packet P2 described above.
The roadside communication device 5A2 of the group G1 that has received the wireless packet P2 executes processing according to the transfer determination processing shown in FIG.

  In this case, since the prefecture code 22 of the wireless packet P2 and the prefecture code stored in the roadside communication device 5A2 are both “A prefecture”, the roadside communication device 5A2 refers to the road transfer table 17 and transmits the transmission source of the wireless packet P2. It is determined whether or not the combination of the communication device ID and the destination communication device ID is registered in the road transfer table 17 (step S6 in FIG. 6).

The road transfer table 17 of the roadside communication device 5A2 has the same contents as the road transfer table 17 of the roadside communication device 5B2 shown in FIG.
Therefore, the combination of the source communication device ID and the destination communication device ID of the wireless packet P2 (the transmission source communication device ID is “11” and the destination communication device ID is “15”) is not registered in the route transfer table 17. .
Therefore, the second determination unit 13b of the roadside communication device 5A2 determines that the combination of the transmission source communication device ID and the destination communication device ID of the wireless packet P2 is not registered in the road transfer table 17. Then, the communication control unit 13c of the roadside communication device 5A2 discards the wireless packet P2 (step S5 in FIG. 6) and ends the process.

  In this case, the second determination unit 13b, based on the information for identifying the network group included in the communication device ID, the network group to which the roadside communication device 5 that is the transmission source of the wireless packet P2 belongs, and the own device 5A2. It can be determined whether or not the network group to which the group belongs is the same. Therefore, it is possible to prevent forwarding of packets that are transmitted from different network groups in the same prefecture and do not need to be forwarded.

[Second Embodiment]
FIG. 9 is a block diagram illustrating a configuration of the roadside communication device 5 according to the second embodiment.
The roadside communication device 5 according to the present embodiment includes a third determination unit 13d that performs processing related to transfer determination based on the wireless device ID included in the wireless packet, instead of the second determination unit 13b. It differs from the first embodiment in that the machine ID table 18 is stored.

FIG. 10 is a flowchart illustrating a transfer determination process for determining whether or not to perform the transfer between roads of a wireless packet, which is performed by the roadside communication device 5 according to the second embodiment.
The flowchart shown in FIG. 10 is the same as the flowchart of FIG. 6 for each step other than step S16.
Therefore, only step S16 will be described here.

If the roadside communication device 5 according to the present embodiment determines in step S4 that the prefecture code of the wireless packet is the same as the prefecture code of the own device 5, the roadside communication device 5 proceeds to step S16.
In step S16, the third determination unit 13d of the roadside communication device 5 reads the wireless device ID included in the IRC header of the wireless packet and refers to the wireless device ID table 18, so that the wireless device ID included in the wireless packet is It is determined whether or not it is registered in the wireless device ID table 18 (step S16). In the wireless device ID table 18, wireless device IDs indicating roadside communication devices 5 that are permitted as a transmission source of wireless packets for the roadside communication device 5 are registered.

  Accordingly, the third determination unit 13d determines whether the roadside communication device 5 that is the transmission source of the wireless packet is the roadside communication device 5 that is permitted as the transmission source of the wireless packet, based on the wireless device ID of the wireless packet. judge.

  If it is determined in step S16 that the wireless device ID included in the wireless packet is not registered in the wireless device ID table 18, the communication control unit 13c of the roadside communication device 5 proceeds to step S5 and discards the wireless packet ( Step S5), the process is finished.

  On the other hand, if it is determined in step S6 that the combination of the source communication device ID and the destination communication device ID included in the wireless packet is registered in the road transfer table 17, the communication control unit 13c of the roadside communication device 5 It progresses to step S7 and it is determined whether a radio | wireless packet is addressed to the own machine 5 (step S7). The subsequent processing is the same as in the first embodiment.

  As a result, the communication control unit 13c of the roadside communication device 5 of the present embodiment is wireless based on the determination result (step S4) of the first determination unit 13a and the determination result (step S16) of the third determination unit 13d. It is determined whether to transfer a packet between routes or to discard a wireless packet. That is, the communication control unit 13c determines whether or not to perform wireless packet transfer between roads based on the determination result of the first determination unit 13a and the determination result of the third determination unit 13d.

  FIG. 11 is a diagram illustrating a case where roadside communication devices 5 belonging to different network groups are adjacent to each other across a prefectural border. In FIG. 11, except that each roadside communication device 5 is the roadside communication device 5 of the present embodiment, the roadside communication devices 5A1, 5A2, and 5A3 constitute a group G1, and the roadside communication devices 5B1, 5B2 , 5B3 constitute a group G2, and the roadside communication devices 5A4, 5A5, 5A6 constitute a group G3. Each roadside communication device 5 is assigned a communication device ID similar to that shown in FIG.

In the group G1, the roadside communication device 5A1 is assigned “1001” as the wireless device ID, the roadside communication device 5A2 is assigned “1002” as the wireless device ID, and the roadside communication device 5A3 is assigned the wireless device ID. “1003” is assigned.
In the group G2, the roadside communication device 5B1 is assigned “1001” as the wireless device ID, the roadside communication device 5B2 is assigned “1002” as the wireless device ID, and the roadside communication device 5B3 has the wireless device ID. “1003” is assigned.
Further, in the group G3, “2001” is assigned to the roadside communication device 5A4 as the wireless device ID, “2002” is assigned to the roadside communication device 5A5 as the wireless device ID, and the wireless device ID is assigned to the roadside communication device 5A6. “2003” is assigned.

As described above, the wireless device ID is assigned a unique number for each prefecture. Therefore, there is a possibility that the wireless device IDs overlap between the roadside communication devices 5 of the adjacent network groups in other prefectures.
In FIG. 11, the wireless device IDs assigned to the roadside communication devices 5A1, 5A2, and 5A3 included in the group G1 and the roadside communication devices 5B1, 5B2, and 5B3 included in the group G2 adjacent to the group G1 are assigned. A case where the wireless device ID is set to overlap is shown.

  Hereinafter, in FIG. 11, the traffic terminal 6a connected to the roadside communication device 5B1 of the group G2 generates data addressed to the traffic terminal 6b connected to the roadside communication device 5B3 of the same group G2, A case will be described in which a wireless packet P3 including data is wirelessly transmitted by the roadside communication device 5B1 and this wireless packet P3 is received by the roadside communication device 5A2 of the group G1.

The roadside communication device 5A2 of the group G1 that has received the wireless packet P3 executes processing according to the transfer determination processing shown in FIG.
The roadside communication device 5A2 reads various information included in the IRC header of the wireless packet P3. Since the communication type information 21 of the wireless packet P3 is “roadside communication” (step S2 in FIG. 10), the first determination unit 13a of the roadside communication device 5A2 determines the state code of the wireless packet P3, the state code of its own device, Are the same (step S4 in FIG. 10).

Since the prefecture code 22 of the wireless packet P3 is “B prefecture” and the roadside communication device 5A2 stores “A prefecture” as the prefecture code, the first determination unit 13a determines the prefecture code of the wireless packet P3 and the prefecture code of its own device. Are not the same.
Therefore, in this case, as in the first embodiment, the communication control unit 13c of the roadside communication device 5A2 discards the wireless packet P3 (step S5 in FIG. 10) and ends the process.
Thus, even if the wireless device IDs of the roadside communication devices 5A1, 5A2, and 5A3 of the group G1 overlap with the wireless device IDs of the roadside communication devices 5B1, 5B2, and 5B3 of the group G2, the prefectures that do not need to be transferred It is possible to prevent transfer of wireless packets from other roadside communication devices having different values.

  Next, in FIG. 11, the traffic terminal 6c connected to the roadside communication device 5A4 of the group G3 generates data addressed to the traffic terminal 6d connected to the roadside communication device 5A6 of the same group G3, A case will be described in which the wireless packet P4 including the data is wirelessly transmitted by the roadside communication device 5A4, and this wireless packet P4 is received by the roadside communication device 5A2 of the group G1.

As shown in FIG. 11, the roadside communication device 5A4 wirelessly transmits the above-described wireless packet P4.
The roadside communication device 5A2 of the group G1 that has received the wireless packet P4 executes processing according to the transfer determination processing shown in FIG.

  In this case, since the prefecture code 22 of the wireless packet P4 and the prefecture code stored in the roadside communication device 5A2 are both “A prefecture”, the roadside communication device 5A2 refers to the wireless device ID table 18 and refers to the wireless device of the wireless packet P4. It is determined whether or not the ID is registered in the wireless device ID table 18 (step S16 in FIG. 10).

FIG. 12 is a diagram illustrating an example of the wireless device ID table 18 included in the roadside communication device 5A2.
Since the roadside communication device 5A2 can perform road-to-road communication between the roadside communication device 5A1 and the roadside communication device 5A3 of the same group G1, the wireless device ID table 18 includes the roadside communication device 5A1 and the roadside communication device 5A3. The assigned wireless device IDs “1001” and “1003” are registered.

Therefore, the wireless device ID (“2001”) of the wireless packet P4 is not registered in the wireless device ID.
Accordingly, the third determination unit 13d of the roadside communication device 5A2 determines that the wireless device ID of the wireless packet P4 is not registered in the wireless device ID table 18. Then, the communication control unit 13c of the roadside communication device 5A2 discards the wireless packet P4 (step S5 in FIG. 6) and ends the process.

  As described above, the third determination unit 13d allows the roadside communication device 5 that is the transmission source of the wireless packet as the transmission source of the wireless packet based on the wireless device ID to which a unique number is assigned in each prefecture. Therefore, each roadside communication device 5 can be identified by the wireless device ID within the same prefecture. As a result, it is possible to prevent packets that are transmitted from different network groups within the same prefecture from being transferred and that do not need to be transferred.

Further, since the wireless device ID is unique for each prefecture, the wireless device ID may overlap between the roadside communication devices 5 adjacent to each other across the prefectural border.
On the other hand, in the present embodiment, whether or not to perform the inter-road transfer of the received wireless packet using not only the determination result of the third determination unit 13d but also the determination result of the first determination unit 13a. Since the determination is made, in determining whether the roadside communication device 5 that is the transmission source of the wireless packet is the roadside communication device 5 that is permitted as the transmission source, the prefecture to which the roadside communication device 5 that is the transmission source of the wireless packet belongs is The determination result as to whether or not it is the same as the prefecture of the own machine 5 can be used.

That is, in this embodiment, even if a wireless packet transmitted from a network group belonging to another prefecture is received, it is determined that there is no need to transfer a wireless packet from another prefecture between the roads. Is discarded.
Thereby, it is possible to more effectively prevent wireless packets that do not need to be transferred.

[Others]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.
For example, in the first embodiment, whether or not to execute wireless packet transfer between roads based on the determination result regarding the prefecture code by the first determination unit 13a and the determination result regarding the communication device ID by the second determination unit 13b. However, the determination by the second determination unit 13b may not be performed if there is no possibility that the communication device IDs overlap between adjacent network groups. That is, in FIG. 6, if it is determined in step S4 that the prefecture code of the wireless packet is the same as the prefecture code of the own device 5, the process may proceed to step S7.

In the first embodiment, after the communication control unit 13c determines whether or not the transfer of the wireless packet can be performed between the roads based on the determination result by the first determination unit 13a, the communication control unit 13c performs wireless communication based on the determination result by the second determination unit 13b. Although the case of determining whether or not the transfer of the packet between the roads can be performed is illustrated, the first determination unit after determining whether or not the transfer of the wireless packets between the roads can be performed based on the determination result by the second determination unit 13b. It may be determined whether or not the transfer of the wireless packet can be performed based on the determination result of 13a.
Note that the determination by the second determination unit 13 b is performed based on the communication device ID assigned to each roadside communication device 5. Therefore, the determination by the second determination unit 13 b has a larger processing burden than the prefecture code including the plurality of roadside communication devices 5.
Therefore, the processing load can be reduced by executing the determination by the prefecture code first, rather than the determination by the communication device ID given to each roadside communication device 5 as in the first embodiment.

  Moreover, in 1st Embodiment, although the roadside communication apparatus 5 provided with the 1st determination part 13a and the 2nd determination part 13b was shown, in addition to these, by radio | wireless machine ID shown in 2nd Embodiment It is good also as a structure provided with the 3rd determination part 13d which performs determination. In this case, the roadside communication device 5 performs the inter-road transfer of the wireless packet based on the determination result by the first determination unit 13a, the determination result by the second determination unit 13b, and the determination result by the third determination unit 13d. It can be determined whether or not.

  Moreover, in 2nd Embodiment, after the 1st determination part 13a performed the determination regarding a prefecture code, the case where the 3rd determination part 13d performed the determination regarding radio | wireless machine ID was illustrated, but the roadside communication apparatus which belongs to other prefectures If there is no possibility of receiving a wireless packet from 5, the determination by the first determination unit 13a may not be performed. That is, in FIG. 10, when the wireless packet is determined to be “roadside communication” in step S <b> 2, the process may proceed to step S <b> 16 and the determination by the third determination unit 13 d may be performed.

  In this case, since the wireless device ID is unique in each prefecture, each roadside communication device 5 can be specified by the wireless device ID. As a result, it is possible to prevent packets that are transmitted from different network groups within the same prefecture from being transferred and that do not need to be transferred.

  The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Traffic control system 2 Central apparatus 3 Network network 4 Router 5, 5A1, 5A2, 5A3, 5A4, 5A5, 5A6, 5B1, 5B2, 5B3 Roadside communication device 6, 6a, 6b, 6c, 6d Traffic terminal 7 In-vehicle communication device DESCRIPTION OF SYMBOLS 8 Wired communication path 10 Wireless communication part 11 Wired communication part 12 Processing apparatus 13 Processing part 13a 1st determination part 13b 2nd determination part 13c Communication control part 13d 3rd determination part 14 Memory | storage part 16 IP transfer table 17 Route transfer table 18 Radio ID table 21 Communication type information 22 Prefecture code 23 Radio ID
24 Sender ID
25 Destination communication device ID
26 Source communication device ID
P1, P2, P3, P4 Wireless packets G1, G2, G3, G4 Network group

Claims (11)

A communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas,
The plurality of roadside communication devices are:
First determining whether the area code indicating the management area to which the other roadside communication apparatus to which the other roadside communication apparatus belongs included in the packet from the other roadside communication apparatus is the same as the area code indicating the management area to which the own roadside communication apparatus belongs is the same A determination unit;
A communication control unit comprising: a communication control unit that determines whether or not to execute the inter-road transfer of the packet based on a determination result of the first determination unit. The plurality of roadside communication devices are provided with first identification information for identifying each roadside communication device,
The packet includes first identification information indicating the other roadside communication device,
Based on first identification information indicating the other roadside communication device, further comprising a second determination unit for determining whether the other roadside communication device is a roadside communication device permitted as a transmission source of the packet;
2. The communication control unit according to claim 1, wherein the communication control unit determines whether or not to perform the inter-road transfer of the packet based on a determination result of the first determination unit and a determination result of the second determination unit. The communication system described. The second determination unit includes a table in which first identification information indicating a roadside communication device permitted as a transmission source of the packet is registered. The second determination unit refers to the table, and the other roadside communication device The communication system according to claim 2, wherein it is determined whether or not the roadside communication device is permitted as a transmission source. The communication system according to claim 2, wherein the communication control unit performs determination based on a determination result of the second determination unit after performing determination based on the determination result of the first determination unit. At least some of the plurality of roadside communication devices constitute a network group capable of communicating with each other in the same management area,
The first identification information indicating the other roadside communication device included in the packet includes information for identifying a network group to which the other roadside communication device belongs, according to any one of claims 2 to 4. The communication system described. The plurality of roadside communication devices are provided with second identification information that is identification information different from the first identification information and is unique for each of the plurality of management areas,
The packet includes second identification information indicating the other roadside communication device,
Based on second identification information indicating the other roadside communication device, further comprising a third determination unit for determining whether the other roadside communication device is a roadside communication device permitted as a transmission source of the packet;
The communication control unit determines whether or not to perform inter-route transfer of the packet based on at least a determination result of the first determination unit and a determination result of the third determination unit. The communication system according to any one of claims 1 to 4. A communication system in which a plurality of roadside communication devices are provided in each of a plurality of management areas,
The plurality of roadside communication devices are given unique identification information in units of the plurality of management areas,
The plurality of roadside communication devices, the roadside on which the other roadside communication device is permitted as a transmission source of the packet based on identification information indicating the other roadside communication device included in the packet from the other roadside communication device A determination unit for determining whether or not the communication device;
A communication control unit comprising: a communication control unit that determines whether or not to execute the inter-road transfer of the packet based on a determination result of the determination unit. The communication system according to any one of claims 1 to 7, wherein the plurality of management areas are prefectures. A roadside communication device provided in any of a plurality of management areas,
First determining whether the area code indicating the management area to which the other roadside communication apparatus to which the other roadside communication apparatus belongs included in the packet from the other roadside communication apparatus is the same as the area code indicating the management area to which the own roadside communication apparatus belongs is the same A determination unit;
A roadside communication device comprising: a communication control unit that determines whether or not to transfer the packet between roads based on a determination result of the first determination unit. A roadside communication device provided in any of a plurality of management areas is a method of transferring packets from other roadside communication devices between roads,
A first step of determining whether or not an area code indicating a management area to which the other roadside communication device to which the other roadside communication device belongs included in the packet is the same as an area code indicating a management area to which the own roadside communication device belongs;
And a second step of determining whether or not to execute the inter-road transfer of the packet based on the determination result of the first step. A computer program for causing a computer to execute a process in which a roadside communication device provided in any of a plurality of management areas transfers a packet from another roadside communication device between roads,
The computer program is
A first step of determining whether or not an area code indicating a management area to which the other roadside communication device to which the other roadside communication device belongs included in the packet is the same as an area code indicating a management area to which the own roadside communication device belongs;
A computer program that causes a computer to execute a second step of determining whether or not to execute the inter-road transfer of the packet based on the determination result of the first step.

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