JP2001358641A - Inter-vehicle communication system and inter-vehicle communication device - Google Patents

Abstract

(57) [Summary] [Problem] To reduce the packet transfer load of inter-vehicle communication. SOLUTION: A vehicle station 3 near a head of a vehicle group 1 and a vehicle 4 near a rear tail, and a vehicle station 5 near a head of the vehicle group 2 and a vehicle 6 near a rear tail are set as relay vehicle stations. It performs packet relay transfer with an adjacent vehicle group via the station.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-to-vehicle communication system that performs wireless communication using a vehicle-to-vehicle communication device mounted on a vehicle, and autonomously forms a vehicle group. TECHNICAL FIELD The present invention relates to a vehicle-to-vehicle communication system and a vehicle-to-vehicle communication device for efficiently relaying and transferring wireless packets between vehicles. 2. Description of the Related Art In a vehicle-to-vehicle communication system, when direct wireless communication is not possible from a transmitting station to a destination station, a packet is delivered to the destination station while repeating relay transfer by another vehicle station. For example, as a conventional general method, when a destination station receives a packet that is not its own station, a method of broadcasting to a vehicle station in a surrounding communication range and transferring the packet to the destination station is a method of a wired network. It is originally thought. [0003] However, in the above-mentioned conventional inter-vehicle communication method, each vehicle attempts to transfer packets to vehicles within a communicable range. There was a disadvantage that the communication load increased. [0004] For this reason, a vehicle group in which a plurality of vehicles running close to each other are grouped is formed autonomously, and the load is reduced by transferring packets between groups using the characteristics of the vehicle group. However, there is a limit to reducing the communication load. The present invention has been made to solve such a problem, and has as its object to significantly reduce communication traffic between vehicle groups by effectively utilizing characteristics unique to the vehicle groups. According to the present invention, there is provided an inter-vehicle communication system for performing wireless communication between vehicles having means for autonomously forming a vehicle group.
The present invention provides an inter-vehicle communication system and an inter-vehicle communication device in which the first and last vehicles of a formed vehicle group are designated as relay vehicle stations that perform packet relay transfer with an adjacent vehicle group. [0007] The invention according to claim 1 of the present invention is formed in an inter-vehicle communication system for performing wireless communication between vehicles provided with means for autonomously forming a vehicle group. A relay vehicle station that performs packet relay between other vehicle groups at the head and tail of the vehicle group is provided, and the relay vehicle station constantly updates and holds vehicle group information on the own vehicle group, based on the own vehicle group information. It is characterized by performing route control of packet transfer within its own vehicle group, specifies relay vehicle stations that connect communication paths between vehicle groups, and an unspecified number of vehicle stations make the same packet meaningless. By suppressing communication, communication traffic between groups of vehicles is suppressed, and by using vehicle group information, it is possible to execute efficient route control to a destination vehicle station in the vehicle group. Vehicle-to-vehicle communication can be realized. According to a second aspect of the present invention, the relay vehicle station according to the first aspect constantly exchanges vehicle group information with a relay vehicle station belonging to an adjacent vehicle group, and a packet destination station received from the adjacent vehicle group is assigned to the own vehicle. If the packet destination station does not exist in the own vehicle group, the route control of the packet transfer in the own vehicle group is performed based on the own vehicle group information when it exists in the own vehicle group. The packet destination station transmits the packet to the relay vehicle station of the group or the other relay vehicle station in the group of the own vehicle to the adjacent group of vehicles. An efficient transfer means that does not generate traffic when not present in a group is provided. According to a third aspect of the present invention, there is provided a means for receiving data from another vehicle station, a data packet for demodulating a received signal, determining whether or not the data packet is a data packet, and transferring the data packet to another station. A packet processing unit that transfers the data packet to a packet transfer unit; and a transfer unit that receives the data packet as input and transfers data to another station based on routing control information described in the data packet. The packet transfer traffic can be efficiently performed by transferring to another station only when the received signal is a data packet to be transferred to another station. FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) A first embodiment will be described with reference to FIGS. FIG. 1 is a conceptual diagram showing a first configuration example of an inter-vehicle communication system according to the present invention.
3, 4, and 8 to 10 indicate vehicle stations included in the vehicle group 1, 5 and 6 indicate vehicle stations included in the vehicle group 2, and 7 indicates a wireless communication link between the vehicle stations 4 and 5. FIG. 2 is a conceptual diagram showing an example of a vehicle group information table in the inter-vehicle communication system according to the present invention.
11 is a vehicle group information table, 212 is a vehicle ID column, 213
Is a position information column, 214 is a time column that describes the time at which the position information described in the position information column 213 is obtained, 215 is an attribute column that represents positioning within the vehicle group, and the lines shown in 216 to 220 are The entry corresponding to the vehicle is shown. Note that the vehicle group information table 211 shown in FIG.
Corresponds to the vehicle group 1 shown in FIG. FIG. 4 shows an example of the configuration of a communication device in an inter-vehicle communication system according to the present invention. 100 is a vehicle station communication device, 101 is a receiving unit, 102 is a packet processing unit, and 103 is a vehicle group information management unit. , 104 is a memory for storing vehicle group information, 105 is a packet transfer unit, 106
Indicates a transmission unit, and 107 indicates a transfer control signal line. FIG. 5 shows an example of a format of a vehicle information packet in the inter-vehicle communication system according to the present invention, wherein 221 is a vehicle information packet, 222 is a packet header, 223 is a transmission time field, 224 is a driving lane field, 225 is a traveling position field, 226
Indicates other information. FIG. 6 shows an example of the format of a data packet in the inter-vehicle communication system according to the present invention, wherein 230 is a data packet, 231 is a packet header, 232 is a routing information field, 233 and 2
34 indicates a relay station address field, and 235 indicates a data field. The vehicle group 1 has five vehicle stations 3, 4, 8, 9, 1
0, in which the vehicle station 3,
The vehicle station 4 is located at the rear end. These operate as relay vehicle stations and have a function as a window when the vehicle group 1 communicates with an adjacent vehicle group. Similarly, in the vehicle group 2, the vehicle station 5 located at the head of the traveling direction and the vehicle station 6 located at the end operate as relay vehicle stations. The means for determining a relay vehicle station in each vehicle group will be described. In each of the vehicle groups 1 and 2, a vehicle information packet 221 shown in FIG. 5 is communicated at regular time intervals.
The vehicle information packet 221 includes a header 222, a transmission time 223 of the vehicle information packet 221, a lane number 224 where the own vehicle is running, a running position 225 of the own vehicle, and the like.
The traveling position information 225 is for grasping the positional relationship between the vehicles in the vehicle group, and may be either an absolute position or a relative position as long as the positional relationship is known. When the vehicle station receives a packet from another vehicle station, it demodulates in the receiving section 101 and converts the packet received in the packet processing section 102 into a vehicle information packet 221.
Is determined. Here, an identifier for packet determination may be included in the header 222. When the received packet is the vehicle information packet 221, the packet is transferred to the vehicle group information management unit 103, and the vehicle group information management unit 103 constructs the vehicle group information table 211. For example, in the vehicle group 1, when the vehicle information packets 221 are received from all the vehicle stations, the vehicle group information table 211 is constructed. The vehicle group information table 211 includes an ID 212 and position information 213 (traveling lane and traveling position) of a vehicle station constituting the vehicle group 1, a packet transmission time 214, and an attribute 215.
Is described in the attribute 215, and the vehicle station that runs first in the positional relationship within the vehicle group is TOP, and the vehicle station that runs last is T
Therefore, the vehicle station 3 is determined to be the relay vehicle station at the head of the vehicle group, and the vehicle station 4 is determined to be the relay vehicle station at the tail of the vehicle group. Since the vehicle information packet 221 is transmitted at fixed time intervals, the vehicle group information table 211 is also updated at the same time intervals. Similarly, in the vehicle group 2, the vehicle station 5 is determined as the leading relay vehicle station, and the vehicle station 6 is determined as the relay vehicle station at the tail of the vehicle group. For example, when transmitting a packet from the vehicle group 2 to the vehicle station 3 of the vehicle group 1, the vehicle station 5 is set so that the vehicle station 4 which is the relay vehicle station of the vehicle group 1 becomes the first hop. Starts transmission. The vehicle station 4 has the vehicle group information of the vehicle group 1, and determines a transfer route such as the vehicle station 4 → the vehicle station 8 → the vehicle station 3 so that the route to the destination station is the shortest, The transfer in the vehicle group 1 is started with the data packet 230 shown in FIG. The data packet 230 describes the address of the vehicle station that performs the transfer relay. For example, the address of the vehicle station 8 is described in the relay station A233. Note that the number of relay stations accommodated in the path control information field 232 is arbitrary. Also, here, the transfer route is described as being the shortest route, but the transfer route may be determined in consideration of the radio wave condition. The vehicle station 4 transmits the data packet 230 to the vehicle station 8, and the vehicle station 8 transfers the packet to the vehicle station 3 as the destination station. At this time, in the vehicle station 8, the receiving unit 101 demodulates the received data packet, the packet processing unit 102 determines that the packet is the data packet 230, and the header information 231 indicates whether it is the own station or another station. Determine,
If it is addressed to another station, the control is transferred to the packet transfer unit 105 to start the packet transfer processing to the next station. If the packet processing unit 102 determines that the packet is the vehicle group information packet 221, the data is transferred to the vehicle group management unit 103, and the data is transferred to the vehicle group information 211.
Generate and update The packet transfer process may refer to the routing control information field 232 in the packet,
The route may be reconstructed based on the vehicle group information held by the own station. For example, when the vehicle group information has been updated, the positional relationship of the vehicle stations has also changed, which may have changed the optimal transfer route. The transfer route is determined, and the transfer route is notified to the packet transfer unit 105 via the transfer control signal line 107. However, when the route is reconstructed, the information of the route control field 232 in the packet must be updated. As described above, according to this embodiment, the communication traffic between the vehicle groups is reduced by restricting the communication permission between the vehicle groups to a specific vehicle station (relay vehicle station). An inter-vehicle communication system can be realized. (Embodiment 2) A second embodiment will be described with reference to FIGS. FIG. 3 shows a second embodiment of the inter-vehicle communication method according to the present invention.
FIG. 11 is a conceptual diagram showing an example of the configuration of a vehicle group;
Is a vehicle station included in the vehicle group 11, and 15 to 17 are vehicle groups 12
, 18 is a vehicle station included in the vehicle group 13,
19 is a wireless communication link between the vehicle stations 14 and 15, 2
0 indicates a wireless communication link between the vehicle stations 17 and 18. The numbers given in FIGS. 4 to 6 are the same as those described in the first embodiment. FIG. 7 is a conceptual diagram showing an example of a vehicle group information packet in the inter-vehicle communication system according to the present invention.
Is a vehicle group information packet, 241 is a packet header, 242
Indicates vehicle group information. The vehicle group information 242 describes the contents of the vehicle group information table. The basic operation of this embodiment is the same as that of the first embodiment, and different points will be described below. In the vehicle groups 12 to 14, vehicle information is exchanged between the vehicle stations to which they belong, and vehicle group information is generated for each vehicle group. Further, between adjacent vehicle groups, each other's vehicle group information is exchanged between respective relay vehicle stations using the vehicle group information packet shown in FIG. To hold. For example, from the vehicle group 13 to the vehicle station 1 of the vehicle group 11
When the data packet is transmitted with the destination station 4 as the destination station, the data packet is transmitted from the vehicle station 18 which is the relay vehicle station of the vehicle group 13 to the vehicle station 17 which is the relay vehicle station of the vehicle group 12 which is the adjacent vehicle group. Is done. At this time, the vehicle station 18 refers to the adjacent vehicle group information, and the vehicle station 17 is determined to be the first hop. The vehicle station 17 determines from the own vehicle group information that the destination of the received data packet does not exist in the own vehicle group, and determines to relay to the adjacent vehicle group.
Since the vehicle group 13 which is an adjacent vehicle group to the vehicle group is a packet transmission source, the data packet is transferred to the vehicle station 15 which is the other relay vehicle station in the own vehicle group 12. Here, the route control within the own vehicle group is performed by the same method as described in the first embodiment. The vehicle station 15 which has received the data packet determines that the vehicle 14 which is a relay vehicle station of the vehicle group 11 is to be the first hop and transmits it to the vehicle group 11 which is an adjacent vehicle group. Vehicle station 14 that has received the data packet
Determines that the packet is addressed to its own station, and performs packet processing. As described above, according to the present embodiment, efficient relay transfer can be performed depending on the packet destination, transfer delay can be minimized, and the transmission efficiency of the entire inter-vehicle communication system can be improved. it can. According to the vehicle-to-vehicle communication system according to the present invention,
By utilizing the characteristics of the vehicle group, communication traffic between the vehicle groups can be reduced. That is, by specifying the relay vehicle stations at the head and tail of the vehicle group, respectively, and limiting the communication between the vehicle groups to the relay vehicle station, wireless communication between the vehicles beyond the vehicle group range is reduced, and an efficient vehicle An inter-vehicle communication system can be realized. Further, according to the present invention, the same effect as reducing communication traffic between individual vehicles can be obtained by setting the vehicle group finely.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram showing a configuration example in a first embodiment of an inter-vehicle communication system according to the present invention. FIG. 2 is a first diagram in an inter-vehicle communication system according to the present invention.
FIG. 3 is a conceptual diagram showing an example of vehicle group information according to the embodiment of the present invention. FIG. 3 is a conceptual diagram showing a configuration example of a vehicle-to-vehicle communication system according to the second embodiment of the present invention. FIG. 5 is a conceptual diagram showing an example of a format of a vehicle information packet in an inter-vehicle communication system according to the present invention; FIG. 6 is a conceptual diagram showing a format example of a data packet in an inter-vehicle communication system according to the present invention; FIG. 7 is a conceptual diagram showing a format example of a vehicle group information packet in an inter-vehicle communication system according to the present invention. [Description of References] 1, 2, 11, 12, 13 Vehicle Groups 3 to 6, 8, 9 Vehicle Station 7, 19, 20 Wireless link 100 Communication device 101 Receiving unit 102 Packet processing unit 103 Vehicle group information management unit 104 Memory 105 Packet transfer unit 10 6 Transmission unit 107 Transfer control signal line 211 Vehicle group information table 212 Vehicle ID column 213 Position information column 214 Time column 215 Attribute column 216 to 220 Entry 221 Vehicle information packet 222 Packet header 223 Transmission time field 224 Running lane field 225 Running position field 226 Other information 230 Data packet 231 Packet header 232 Route control information field 233, 234 Relay station address 235 Data field 240 Vehicle group information packet 241 Packet header 242 Vehicle group information field

Claims (1)

Claims: 1. An inter-vehicle communication system for performing wireless communication between vehicles having means for autonomously forming a group of vehicles,
A relay vehicle station that performs packet relay between other vehicle groups is provided at the head and tail of the formed vehicle group, and the relay vehicle station constantly updates and holds vehicle group information regarding the own vehicle group, An inter-vehicle communication system, wherein a route control for packet transfer within a vehicle group is performed based on group information. 2. The relay vehicle station according to claim 1 constantly exchanges vehicle group information with a relay vehicle station belonging to an adjacent vehicle group, and a packet destination station received from the adjacent vehicle group exists in the own vehicle group. Performs the packet transfer route control in the own vehicle group based on the own vehicle group information, and when the packet destination station does not exist in the own vehicle group, transfers the packet to a relay vehicle station of an adjacent vehicle group different from the packet transmission source. Or an inter-vehicle communication system in which the other relay vehicle station in the own vehicle group transfers the data to an adjacent vehicle group. 3. A means for receiving data from another vehicle station, demodulating the received signal, determining whether the data packet is a data packet, and determining that the data packet is a data packet to be transferred to another station. Packet processing means for transferring a packet to a packet transfer unit, and the data packet as input,
Transfer means for transferring data to another station based on the route control information described in the data packet.