COMMUNICATION DEVICE, COMMUNICATION RELAY DEVICE, COMMUNICATION METHOD, COMMUNICATION RELAY METHOD, AND COMPUTER PROGRAM

Abstract

To provide a communication device and method, a communication relay device and a method, and a computer program that improve quality, such as continuity and stability, of a multiple patch communication in vehicle communication.SOLUTION: There is provided, a communication system equipped with a plurality of vehicles having a communication device or a communication relay device, wherein the communication device comprises a vehicle-to-vehicle communication unit for performing vehicle-to-vehicle communication with other vehicles, a wireless communication unit for connecting to a wireless communication network and performing wireless communication, a multiple path communication unit for performing a multiple path communication that uses a plurality of communication paths, and a control unit for selecting, from among other vehicle communication paths which are communication paths via vehicle-to-vehicle communication and host vehicle communication paths which are communication paths of wireless communication, a plurality of communication path which is used for multiple path communication. The control unit calculates, on the basis of the vehicle information of other vehicles received by vehicle-to-vehicle communication, a vehicle quality value that indicates quality related to the other vehicle communication paths of the other vehicles, and creates on the basis of the vehicle quality value an other vehicle candidate list that is a list of the candidate other vehicles used for multiple path communication.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a communication device, a communication relay device, a communication method, a communication relay method, and a computer program. [Background technology]

[0002] Conventionally, as a technology using multi-path communication, for example, multi-path communication in which a vehicle uses multiple roadside units and multi-path communication by vehicle-to-vehicle communication are known (for example, see Non-Patent Documents 1, 2, and 3). In the conventional technology, in an environment in which a vehicle can communicate with multiple roadside units, multi-path communication using multiple roadside units is implemented, but when the vehicle moves out of the communication range of the roadside units, the multi-path communication is switched to communication using 4G (fourth generation mobile communication system) that the vehicle can use. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] “60 GHz Wireless System Employing Multi-Link Connection Targeting for V2X Applications”, IEICE Technical Report, SR2018-59, pp. 3-4, October 2018 [Non-Patent Document 2] “Multipath TCP on a VANET: A Performance Study”, SIGMETRICS'17, June 5 - 9, 2017 [Non-Patent Document 3] “Mobility-aware multimedia data transfer using Multipath TCP in Vehicular Network”, 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC) Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, when a vehicle moves out of the communication range of a roadside unit, it is not possible to implement multi-route communication. Also, when a communication route used for multi-route communication is secured by vehicle-to-vehicle communication, the stability of the communication route is an issue.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to improve the quality, such as the continuity and stability, of multi-route communication. [Means for solving the problem]

[0006] (1) One aspect of the present invention is a communication device mounted on a vehicle, the device including: an inter-vehicle communication unit that performs inter-vehicle communication with another vehicle; a wireless communication unit that connects to a wireless communication network and performs wireless communication; a multiple-route communication unit that performs multiple-route communication using multiple communication routes simultaneously; and a control unit that selects multiple communication routes to be used simultaneously for the multiple-route communication from an other-vehicle communication route that is a communication route via the inter-vehicle communication and a vehicle communication route that is a communication route for the wireless communication. the control unit calculates a vehicle quality value indicating a quality of an other-vehicle communication route of the other vehicle based on vehicle information of the other vehicle received through the vehicle-to-vehicle communication, and selects a plurality of communication routes to be used simultaneously for the multi-route communication based on the vehicle quality value, the vehicle information being vehicle speed, traveling direction, and position information; It is a communication device. ( 2 In one aspect of the present invention, the vehicle information of the other vehicle includes information indicating the position, speed, and traveling direction of the other vehicle, the vehicle quality value indicates a relative distance between the vehicle and the other vehicle, and the control unit, when selecting multiple communication routes to be used simultaneously in the multiple-route communication, selects from among an other-vehicle communication route, which is a communication route via the inter-vehicle communication between only other vehicles whose relative distance is less than a predetermined threshold, and the vehicle communication route. 1 ) communication device. ( 3 ) One aspect of the present invention is A communication device mounted on a vehicle includes an inter-vehicle communication unit that performs inter-vehicle communication with another vehicle, a wireless communication unit that connects to a wireless communication network and performs wireless communication, a multiple-route communication unit that performs multiple-route communication using multiple communication routes simultaneously, and a control unit that selects multiple communication routes to be used simultaneously for the multiple-route communication from an other-vehicle communication route that is a communication route via the inter-vehicle communication and a vehicle communication route that is a communication route for the wireless communication,The vehicle information of the other vehicle includes communication carrier information indicating the operator of the wireless communication network used by the other vehicle, and the control unit is a communication device that, when selecting multiple communication routes to be used simultaneously for the multi-route communication, selects from among an other-vehicle communication route, which is a communication route via vehicle-to-vehicle communication between only the other vehicle and the other vehicle, which has different communication carrier information from the own vehicle, and the own-vehicle communication route. ( 4 In one aspect of the present invention, the control unit creates an other vehicle candidate list, which is a list of other vehicles that are candidates for communication routes used in the multi-route communication, based on the vehicle quality value, measures line quality when using other vehicle communication routes of other vehicles included in the other vehicle candidate list, and selects multiple communication routes to be used in the multi-route communication based on the measurement result of the line quality. 1 ) or ( 2 ) communication device.

[0007] ( 5 One aspect of the present invention is a communication relay device mounted on a vehicle, comprising the above items (1) to ( 4 a wireless communication unit that connects to a wireless communication network and performs wireless communication; a communication relay unit that relays communication between an other-vehicle communication path that is a communication path for the vehicle-to-vehicle communication and a vehicle-specific communication path that is a communication path for the wireless communication; and a control unit that controls the relay of communication, wherein the control unit transmits vehicle information of the vehicle-specific communication path via the vehicle-to-vehicle communication. ( 6 In one aspect of the present invention, the control unit manages a total value of relay communication volume and determines whether or not to relay the communication based on the total value of relay communication volume. 5 ) communication relay device. ( 7 )One aspect of the present invention is the above-mentioned (wherein the wireless communication unit can use a plurality of wireless communication networks, the control unit measures line quality for each of the plurality of wireless communication networks, and determines which of the plurality of wireless communication networks is to be used to relay the communication based on the measurement result of the line quality. 5 ) or (6 ) is a communication relay device.

[0008] (8) One aspect of the present invention is a communication method including: a vehicle-to-vehicle communication step in which a communication device mounted on a vehicle performs vehicle-to-vehicle communication with another vehicle; a wireless communication step in which the communication device connects to a wireless communication network and performs wireless communication; a multiple-route communication step in which the communication device performs multiple-route communication using multiple communication routes simultaneously; and a control step in which the communication device selects multiple communication routes to be used simultaneously for the multiple-route communication from among an other-vehicle communication route that is a communication route via the vehicle-to-vehicle communication and a vehicle communication route that is a communication route for the wireless communication, wherein the control step calculates a vehicle quality value indicating a quality of the other-vehicle communication route of the other vehicle based on vehicle information of the other vehicle received through the vehicle-to-vehicle communication, and selects multiple communication routes to be used simultaneously for the multiple-route communication based on the vehicle quality value, wherein the vehicle information is vehicle speed, direction of travel, and position information. (9) One aspect of the present invention is a communication method including: a vehicle-to-vehicle communication step in which a communication device mounted on a vehicle performs vehicle-to-vehicle communication with another vehicle; a wireless communication step in which the communication device connects to a wireless communication network and performs wireless communication; a multiple-route communication step in which the communication device performs multiple-route communication using multiple communication routes simultaneously; and a control step in which the communication device selects multiple communication routes to be used simultaneously for the multiple-route communication from among an other-vehicle communication route that is a communication route via the vehicle-to-vehicle communication and a vehicle-specific communication route that is a communication route for the wireless communication, wherein vehicle information of the other vehicle includes communication carrier information indicating an operator of a wireless communication network used by the other vehicle, and the control step selects from among the other-vehicle communication route that is a communication route via the vehicle-to-vehicle communication between only other vehicles and which has communication carrier information different from the vehicle-specific communication route when selecting the multiple communication routes to be used simultaneously for the multiple-route communication. (10) One aspect of the present invention is a communication relay method including: a vehicle-to-vehicle communication step in which a communication relay device mounted on a vehicle performs vehicle-to-vehicle communication with another vehicle equipped with any of the communication devices (1) to (4) described above; a wireless communication step in which the communication relay device connects to a wireless communication network and performs wireless communication; a communication relay step in which the communication relay device relays communication between an other-vehicle communication path that is a communication path for the vehicle-to-vehicle communication and a vehicle-specific communication path that is a communication path for the wireless communication; and a control step in which the communication relay device controls the relaying of the communication, wherein in the control step, the communication relay device transmits vehicle information of the vehicle-specific communication via the vehicle-to-vehicle communication.

[0009] (11) One aspect of the present invention is a computer program for causing a computer of a communication device mounted on a vehicle to execute the communication method according to either of (8) or (9) above. (12) One aspect of the present invention is a computer program for causing a computer of a communication relay device mounted on a vehicle to execute the communication relay method according to (10) above. Effect of the Invention

[0010] According to the present invention, it is possible to obtain an effect of improving the quality, such as the continuity and stability, of multi-route communication. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a configuration example of a communication system according to an embodiment; [Diagram 2] 1 is a block diagram showing an example of the configuration of a communication device according to an embodiment; [Diagram 3] 1 is a block diagram showing an example of a configuration of a communication relay device according to an embodiment; [Figure 4] 1 is a sequence diagram showing an example of an overall procedure of a multiple-route communication method according to an embodiment; [Diagram 5] 10 is a flowchart illustrating an example of a procedure of a different vehicle candidate list updating method according to an embodiment. [Figure 6] 11 is a flowchart illustrating an example of a procedure of a sub-flow list updating method according to an embodiment. [Figure 7] 1 is a block diagram showing an example of a configuration of a communication relay device according to an embodiment; [Figure 8] 1 is a sequence diagram showing an example of an overall procedure of a multiple-route communication method according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] [First embodiment] Fig. 1 is a block diagram showing a configuration example of a communication system 1 according to an embodiment. In Fig. 1, a vehicle 2 includes a communication device 10. A vehicle 3 includes a communication relay device 30. The vehicle 2 can perform multi-route communication by the communication device 10. The vehicle 3 can provide a communication route used for the multi-route communication of the vehicle 2 by the communication relay device 30.

[0014] The vehicle 2 can communicate using the wireless communication network NWa of the operator A by using the communication device 10. For example, the vehicle 2 can communicate with a server 4 on the Internet NWc via the wireless communication network NWa by using the communication device 10. A wireless communication path 110 between the vehicle 2 and the wireless communication network NWa is a communication path that the vehicle 2 has and that can be used for multi-path communication.

[0015] Vehicle 2 can perform inter-vehicle communication with vehicle 3 by using communication device 10. Vehicle 3 can perform inter-vehicle communication with vehicle 2 by using communication relay device 30. An inter-vehicle communication path 120 between vehicle 2 and vehicle 3 is a communication path that vehicle 2 has and that can be used for multi-route communication.

[0016] The vehicle 3 can communicate using the wireless communication network NWb of the operator B by the communication relay device 30. For example, the vehicle 3 can communicate with a server 4 on the Internet NWc via the wireless communication network NWb by the communication relay device 30. The wireless communication path 130 between the vehicle 3 and the wireless communication network NWb is a communication path that the vehicle 3 has and that can be used for multi-path communication.

[0017] The wireless communication networks NWa and NWb may be, for example, a mobile communication system such as 4G (fourth generation mobile communication system) or 5G (fifth generation mobile communication system), or may be a wireless LAN (Local Area Network) system.

[0018] The wireless communication network NWa and the wireless communication network NWb are systems of different carriers A and B. Therefore, even in the same service area, the wireless communication network NWa and the wireless communication network NWb may have different wireless communication qualities. For example, in the same service area, even if the wireless communication network NWa temporarily experiences worse wireless communication quality than normal due to terminal congestion, the wireless communication network NWb may provide normal wireless communication quality.

[0019] The operators A and B are, for example, MNOs (Mobile Network Operators) and MVNOs (Mobile Virtual Network Operators).

[0020] Hereinafter, a communication route that is owned by a vehicle 2 that performs multi-route communication and that can be used for the multi-route communication may be referred to as a subflow.

[0021] Vehicle 2 has, as subflows, a wireless communication path 110 and a vehicle-to-vehicle communication path 120 between vehicle 2 and vehicle 3, through communication device 10. Vehicle 2 has the same number of vehicle-to-vehicle communication paths 120 as the number of vehicles 3 with which the vehicle 2 can perform vehicle-to-vehicle communication through communication device 10. Vehicle 2 performs multi-path communication using the multiple subflows that the vehicle has through communication device 10.

[0022] 2 is a block diagram showing an example of the configuration of a communication device according to the present embodiment. In FIG. 2, a communication device 10 includes a vehicle-to-vehicle communication unit 11, a wireless communication unit 12, a multiple-route communication unit 13, a control unit 14, and a storage unit 15.

[0023] Each function of the communication device 10 is realized by the communication device 10 including computer hardware such as a CPU (Central Processing Unit) and a memory, and the CPU executing a computer program stored in the memory. The communication device 10 may be configured using a general-purpose computer device, or may be configured as a dedicated hardware device.

[0024] The vehicle-to-vehicle communication unit 11 performs vehicle-to-vehicle communication with other vehicles. The wireless communication unit 12 connects to a wireless communication network NWa and performs wireless communication.

[0025] The multi-route communication unit 13 performs multi-route communication using multiple subflows owned by the vehicle. For example, Multipath TCP (MPTCP) or Multi-QUIC can be used as a communication protocol for realizing the multi-route communication.

[0026] The control unit 14 controls each unit of the communication device 10. The control unit 14 selects a plurality of subflows to be used for the multi-route communication by the multi-route communication unit 13 from a plurality of subflows possessed by the vehicle. Specifically, the control unit 14 selects a plurality of communication paths to be used for the multi-route communication from a communication path via the inter-vehicle communication path 120 possessed by the vehicle and a wireless communication path 110.

[0027] In the communication device 10, the communication path via the inter-vehicle communication path 120 corresponds to the other-vehicle communication path, and the wireless communication path 110 corresponds to the own-vehicle communication path.

[0028] The storage unit 15 stores various data. The storage unit 15 stores an other vehicle candidate list 21 and a sub-flow list 22. The other vehicle candidate list 21 is a list of other vehicles that are candidates for communication routes used in multi-route communication. The subflow list 22 is a list of candidates for communication paths used in multi-path communication.

[0029] 3 is a block diagram showing an example of the configuration of a communication relay device according to the present embodiment. In FIG. 3, the communication relay device 30 includes a vehicle-to-vehicle communication unit 31, a wireless communication unit 32, a communication relay unit 33, a control unit 34, and a storage unit 35.

[0030] Each function of the communication relay device 30 is realized by the communication relay device 30 including computer hardware such as a CPU and memory, and the CPU executing a computer program stored in the memory. The communication relay device 30 may be configured using a general-purpose computer device, or may be configured as a dedicated hardware device.

[0031] The vehicle-to-vehicle communication unit 31 performs vehicle-to-vehicle communication with other vehicles. The wireless communication unit 32 connects to the wireless communication network NWb and performs wireless communication.

[0032] The communication relay unit 33 relays communication between the inter-vehicle communication path 120 and the wireless communication path 130 .

[0033] In the communication relay device 30, the inter-vehicle communication path 120 corresponds to the other-vehicle communication path, and the wireless communication path 130 corresponds to the own-vehicle communication path.

[0034] The control unit 34 controls each unit of the communication relay device 30. The control unit 34 controls the communication relay unit 33 to relay communication.

[0035] The control unit 34 transmits vehicle information of the vehicle through vehicle-to-vehicle communication by the vehicle-to-vehicle communication unit 31. The vehicle information includes identification information (vehicle ID) of the vehicle, a time stamp, vehicle speed, traveling direction, location information, identification information (operator ID) of the operator B of the wireless communication network NWb used by the wireless communication unit 32, and the like. The vehicle speed is acquired, for example, from an on-board control device (ECU (electronic control unit)). The traveling direction is acquired, for example, by a measurement value of an on-board sensor. The location information is, for example, location information (latitude, longitude) acquired by an on-board GPS (Global Positioning System). The operator ID is, for example, identification information of an operator such as an MNO set in an on-board SIM (Subscriber Identity Module).

[0036] The vehicle information of vehicle 3 is broadcast by vehicle-to-vehicle communication. The vehicle information broadcast from the vehicle-to-vehicle communication unit 31 of the communication relay device 30 of vehicle 3 is received by the vehicle-to-vehicle communication unit 11 of the communication device 10 of vehicle 2 located within the vehicle-to-vehicle communication range of the vehicle 3.

[0037] The storage unit 35 stores various types of data.

[0038] Next, the overall procedure of the multiple-route communication method according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a sequence diagram showing an example of the overall procedure of the multiple-route communication method according to this embodiment.

[0039] (Step S11) The communication relay device 30 of the vehicle 3 broadcasts the vehicle information of the vehicle 3 through vehicle-to-vehicle communication.

[0040] (Step S12) When the communication device 10 of the vehicle 2 receives the vehicle information broadcast by vehicle-to-vehicle communication from the vehicle 3, it updates the other vehicle candidate list 21. The method of updating the other vehicle candidate list will be described later.

[0041] (Step S13 ) The communication device 10 of the vehicle 2 measures the quality of the line via the inter-vehicle communication path 120 for the vehicles 3 included in the other vehicle candidate list 21 .

[0042] (Step S14) Based on the result of the line quality measurement in step S13, the communication device 10 in the vehicle 2 updates the sub-flow list 22. A method of updating the sub-flow list will be described later.

[0043] (Step S15) The communication device 10 of the vehicle 2 performs multi-route communication using a plurality of subflows included in the subflow list 22. For example, multi-route communication is performed using a plurality of communication paths via each of a plurality of inter-vehicle communication paths 120 included in the subflow list 22. For example, multi-route communication is performed using one or more communication paths via the wireless communication path 110 and one or more inter-vehicle communication paths 120 included in the subflow list 22.

[0044] Next, the other vehicle candidate list updating method according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the procedure of the other vehicle candidate list updating method according to this embodiment.

[0045] The method for updating the other vehicle candidate list shown in Fig. 5 is performed when the communication device 10 of the vehicle 2 receives vehicle information broadcast by vehicle-to-vehicle communication from the vehicle 3. In addition, the method for updating the other vehicle candidate list shown in Fig. 5 may be performed periodically.

[0046] (Step S21) The vehicle-to-vehicle communication unit 11 of the communication device 10 receives the vehicle information broadcast from the vehicle 3 through vehicle-to-vehicle communication.

[0047] (Step S22) The control unit 14 of the communication device 10 checks whether the vehicle 3 (update target vehicle 3) that is the source of the vehicle information received by the vehicle-to-vehicle communication unit 11 is included in the other vehicle candidate list 21. If the result of this check shows that the update target vehicle 3 is included in the other vehicle candidate list 21 (step S22, YES), the process proceeds to step S23, and if the update target vehicle 3 is not included in the other vehicle candidate list 21 (step S22, NO), the process proceeds to step S27.

[0048] (Step S23) The control unit 14 of the communication device 10 calculates a vehicle quality value for the update target vehicle 3. The vehicle quality value for the update target vehicle 3 is a value indicating whether the vehicle-to-vehicle communication path 120 of the update target vehicle 3 is suitable as the first hop of the subflow of the vehicle 2. As an example of this embodiment, the vehicle quality value for the update target vehicle 3 is the reciprocal of the relative distance between the vehicle 2 and the update target vehicle 3. Therefore, the shorter the relative distance between the vehicle 2 and the update target vehicle 3, the larger (better) the vehicle quality value of the update target vehicle 3 becomes. The relative distance between the vehicle 2 (own vehicle) and the update target vehicle 3 (other vehicle) is calculated by the following formulas (1) and (2). Note that the subscript "a", for example, may be expressed as "_a".

[0049] Equation (1) is a calculation formula for the relative distance d(T) at time T when the host vehicle receives vehicle information from another vehicle. In equation (1), the relative distance d(T) is calculated using the position information (latitude, longitude) of the other vehicle included in the vehicle information received by the host vehicle from the other vehicle at time T.

[0050]

number

[0051] T is the time when the vehicle receives vehicle information from the other vehicle. d(t) is the relative distance (km) between the vehicle and the other vehicle at time t. x(t)_other is the latitude of the other vehicle at time t. x(t)_own is the latitude of the vehicle at time t. y(t)_other is the longitude of the other vehicle at time t. y(t)_own is the longitude of the vehicle at time t. The vehicle's position information (latitude, longitude) is, for example, position information (latitude, longitude) obtained by an on-board GPS.

[0052] Equation (2) is a calculation formula for the relative distance d(t) at time t when the vehicle is not receiving vehicle information from other vehicles. In equation (2), the relative distance d(t) at time t is calculated by estimating the change from the relative distance "d(T) = D" corresponding to the time increase from time T to time t "Δt = tT" and adding this to the relative distance d(T).

[0053]

number

[0054] v(t)_other is the vehicle speed (km / h) of the other vehicle at time t. v(t)_own is the vehicle speed (km / h) of the host vehicle at time t. The vehicle speed of the host vehicle is obtained, for example, from the host vehicle's onboard control unit (ECU). Δt is the time increase from time T to time t, "Δt=tT". D is the relative distance d(T) at time T. θ(t)_other is the traveling direction of the other vehicle at time t. θ(t)_own is the traveling direction of the host vehicle at time t. The traveling direction of the other vehicle at time T, θ(T)_other, is included in the vehicle information received by the host vehicle from the other vehicle at time T. The traveling direction of the host vehicle is obtained, for example, as a measurement value of the host vehicle's onboard sensor.

[0055] (Step S24) The control unit 14 of the communication device 10 determines whether the vehicle quality value for the update target vehicle 3 calculated in step S23 exceeds a predetermined threshold value. If the result of this determination is that the vehicle quality value exceeds the predetermined threshold value (step S24, YES), the process proceeds to step S25, and if the vehicle quality value is equal to or less than the predetermined threshold value (step S24, NO), the process proceeds to step S26.

[0056] (Step S25) The control unit 14 of the communication device 10 resets the vehicle quality value of the update target vehicle 3 to the currently calculated vehicle quality value in the other vehicle candidate list 21. As a result, the vehicle ID of the update target vehicle 3 and the latest vehicle quality value exceeding the threshold value are stored in the other vehicle candidate list 21. Thereafter, the process in FIG. 5 is terminated.

[0057] (Step S26) The control unit 14 of the communication device 10 deletes the update target vehicle 3 from the other vehicle candidate list 21. The update target vehicle 3 whose vehicle quality value is equal to or less than a predetermined threshold value is not included in the other vehicle candidate list 21. After that, the process in FIG. 5 ends.

[0058] (Step S27) The control unit 14 of the communication device 10 checks whether the operator ID (communication carrier) of the update target vehicle 3 is different from the operator ID (communication carrier) of the own vehicle. The operator ID of the update target vehicle 3 is included in the vehicle information received from the update target vehicle 3. The operator ID of the own vehicle is obtained from the operator ID set in the on-board SIM. If the operator ID of the update target vehicle 3 is different from the operator ID of the own vehicle, the wireless communication network used by the update target vehicle 3 is different from the wireless communication network NWa used by the own vehicle.

[0059] If it is determined in step S27 that the carrier ID of the update target vehicle 3 is different from the carrier ID of the own vehicle (step S27, YES), the process proceeds to step S28. On the other hand, if the carrier ID of the update target vehicle 3 is the same as the carrier ID of the own vehicle (step S27, NO), the process in FIG. 5 ends. An update target vehicle 3 whose carrier ID (communication carrier) is the same as the carrier ID (communication carrier) of the own vehicle is not included in the other vehicle candidate list 21.

[0060] (Step S28) The control unit 14 of the communication device 10 calculates a vehicle quality value for each update target vehicle 3 whose business operator ID is different from the business operator ID of the own vehicle. The method of calculating the vehicle quality value is the same as that of step S23.

[0061] (Step S29) The control unit 14 of the communication device 10 determines whether the vehicle quality value for the update target vehicle 3 calculated in step S28 exceeds a predetermined threshold. If the result of this determination is that the vehicle quality value exceeds the predetermined threshold (step S29, YES), the process proceeds to step S30. On the other hand, if the vehicle quality value is equal to or less than the predetermined threshold (step S29, NO), the process of FIG. 5 ends. An update target vehicle 3 whose vehicle quality value is equal to or less than the predetermined threshold is not included in the other vehicle candidate list 21.

[0062] (Step S30) The control unit 14 of the communication device 10 adds the update target vehicle 3, whose carrier ID is different from the carrier ID of the host vehicle and whose vehicle quality value exceeds a predetermined threshold, to the other vehicle candidate list 21. As a result, the vehicle ID of the update target vehicle 3 and the latest vehicle quality value exceeding the threshold are stored in the other vehicle candidate list 21. Thereafter, the processing in FIG. 5 is terminated.

[0063] 5 described above, only vehicles 3 whose operator ID (communication carrier) is different from the operator ID (communication carrier) of the vehicle itself and whose vehicle quality value exceeds a predetermined threshold are included (registered) in the other vehicle candidate list 21. The other vehicle candidate list 21 stores the vehicle ID of each registered vehicle 3 and the latest vehicle quality value exceeding the threshold.

[0064] Next, a sub-flow list updating method according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the procedure of the sub-flow list updating method according to this embodiment.

[0065] The sub-flow list update method shown in Fig. 6 is periodically performed for all vehicles 3 included in the other vehicle candidate list 21. Also, the sub-flow list update method shown in Fig. 6 is periodically performed for the wireless communication path 110 of the vehicle 2. Note that, for the sake of convenience, Fig. 6 shows a procedure for the vehicles 3 included in the other vehicle candidate list 21, but the same applies to the wireless communication path 110 of the vehicle 2.

[0066] (Step S41) The control unit 14 of the communication device 10 acquires the other vehicle candidate list 21.

[0067] (Step S42) The control unit 14 of the communication device 10 checks whether the vehicle 3 (subflow update target vehicle 3) included in the other vehicle candidate list 21 is included in the subflow list 22. If the result of this check is that the subflow update target vehicle 3 is included in the subflow list 22 (step S42, YES), the process proceeds to step S43, and if the subflow update target vehicle 3 is not included in the subflow list 22 (step S42, NO), the process proceeds to step S48.

[0068] (Step S43) The control unit 14 of the communication device 10 measures the quality of the line via the vehicle-to-vehicle communication path 120 of the vehicle 3 that is the target of the subflow update. In this line quality measurement, the line quality measurement is performed using a "ping command" or an "iperf command". The control unit 14 measures a packet loss rate and an average RTT (Round Trip Time) by sending a "ping command" to the server 4 of the communication partner via the vehicle-to-vehicle communication path 120 of the vehicle 3 that is the target of the subflow update by the vehicle-to-vehicle communication unit 11. The control unit 14 also measures the average throughput by sending an "iperf command" to the server 4 of the communication partner via the vehicle-to-vehicle communication path 120 of the vehicle 3 that is the target of the subflow update by the vehicle-to-vehicle communication unit 11.

[0069] (Step S44) The control unit 14 of the communication device 10 uses the result of the circuit quality measurement in step S43 to calculate a circuit quality value q_circuit of the subflow update target vehicle 3 according to the following formula (3).

[0070]

number

[0071] q_circuit is the line quality value of the vehicle 3 that is the target of the subflow update. T_average is the average throughput. ploss is the packet loss rate. RTT_average is the average RTT.

[0072] (Step S45) The control unit 14 of the communication device 10 determines whether the circuit quality value q_circuit of the subflow update target vehicle 3 calculated in step S44 exceeds a predetermined threshold value. If the result of this determination is that the circuit quality value q_circuit exceeds the predetermined threshold value (step S45, YES), the process proceeds to step S46, and if the circuit quality value is equal to or less than the predetermined threshold value (step S45, NO), the process proceeds to step S47.

[0073] (Step S46) The control unit 14 of the communication device 10 resets the circuit quality value of the subflow update target vehicle 3 to the currently calculated circuit quality value q_circuit in the subflow list 22. As a result, the vehicle ID of the subflow update target vehicle 3 and the latest circuit quality value exceeding the threshold are stored in the subflow list 22. After that, the processing in FIG. 6 is terminated.

[0074] (Step S47) The control unit 14 of the communication device 10 deletes the subflow update target vehicle 3 from the subflow list 22. The subflow update target vehicle 3 whose circuit quality value q_circuit is equal to or less than a predetermined threshold value is not included in the subflow list 22. After that, the process in FIG. 6 ends.

[0075] In addition, the control unit 14 of the communication device 10 compares the other vehicle candidate list 21 with the sub-flow list 22, and if there is a vehicle 3 that is not included in the other vehicle candidate list 21 but is included in the sub-flow list 22, it deletes the vehicle 3 from the sub-flow list 22.

[0076] (Step S48) The control unit 14 of the communication device 10 measures the line quality via the inter-vehicle communication path 120 of the subflow update target vehicle 3. The line quality measurement method is the same as that of the above-mentioned step S43.

[0077] (Step S49) The control unit 14 of the communication device 10 uses the result of the circuit quality measurement in step S48 to calculate the circuit quality value q_circuit of the subflow update target vehicle 3 by the above formula (3).

[0078] (Step S50) The control unit 14 of the communication device 10 determines whether the circuit quality value q_circuit of the subflow update target vehicle 3 calculated in step S49 exceeds a predetermined threshold. If the result of this determination is that the circuit quality value q_circuit exceeds the predetermined threshold (step S50, YES), the process proceeds to step S51. On the other hand, if the circuit quality value q_circuit is equal to or less than the predetermined threshold (step S50, NO), the process of FIG. 6 ends. A subflow update target vehicle 3 whose circuit quality value q_circuit is equal to or less than the predetermined threshold is not included in the subflow list 22.

[0079] (Step S51) The control unit 14 of the communication device 10 adds the subflow update target vehicle 3, whose circuit quality value q_circuit exceeds a predetermined threshold, to the subflow list 22. As a result, the vehicle ID of the subflow update target vehicle 3 and the latest circuit quality value exceeding the threshold are stored in the subflow list 22. After that, the processing in FIG. 6 is terminated.

[0080] 6 described above, only the vehicles 3 whose line quality values ​​exceed a predetermined threshold are included (registered) in the sub-flow list 22 among the vehicles 3 included in the other vehicle candidate list 21. The vehicles 3 included in the other vehicle candidate list 21 are only the vehicles 3 whose carrier ID (communication carrier) is different from the carrier ID (communication carrier) of the vehicle 2 (own vehicle) and whose vehicle quality values ​​exceed a predetermined threshold. Therefore, the vehicles 3 included in the sub-flow list 22 are only the vehicles 3 whose carrier ID (communication carrier) is different from the carrier ID (communication carrier) of the vehicle 2 (own vehicle), whose vehicle quality values ​​exceed a predetermined threshold, and whose line quality values ​​exceed a predetermined threshold. The subflow list 22 stores the vehicle ID of each registered vehicle 3 and the latest line quality value exceeding the threshold.

[0081] 6 is also performed on the wireless communication path 110 of the vehicle 2. As a result, when the line quality value of the wireless communication path 110 of the vehicle 2 exceeds a predetermined threshold, the wireless communication path 110 of the vehicle 2 is included in the sub-flow list 22. On the other hand, when the line quality value of the wireless communication path 110 of the vehicle 2 is equal to or lower than the predetermined threshold, the wireless communication path 110 of the vehicle 2 is not included in the sub-flow list 22.

[0082] The control unit 14 of the communication device 10 selects, from the subflow list 22, multiple subflows that the multiple-route communication unit 13 uses for multiple-route communication. For example, the control unit 14 selects a predetermined number (multiple) of subflows from the subflow list 22 based on the line quality value in the subflow list 22. For example, the predetermined number (multiple) of subflows are selected from the subflows with higher line quality values. For example, when the wireless communication path 110 of the vehicle 2 is present in the subflow list 22, the wireless communication path 110 of the vehicle 2 and one or more vehicles 3 in the subflow list 22 may be selected.

[0083] The multi-route communication unit 13 performs multi-route communication using a plurality of subflows selected by the control unit 14 .

[0084] The vehicles 3 included in the subflow list 22 are only those whose operator ID (communication carrier) is different from the operator ID (communication carrier) of the vehicle 2 (own vehicle), whose vehicle quality value exceeds a predetermined threshold, and whose line quality value exceeds a predetermined threshold. Therefore, even if the wireless communication quality of the wireless communication network NWa used by the vehicle 2 is significantly degraded, the vehicle 2 can continue the multi-route communication stably by using the wireless communication network NWb used by the vehicle 3 included in the subflow list 22.

[0085] Moreover, the vehicle 3 included in the subflow list 22 is a good vehicle 3 whose vehicle quality value exceeds a predetermined threshold value and whose inter-vehicle communication path 120 is suitable as the first hop of the subflow of the vehicle 2. In this embodiment, the vehicle quality value is the inverse of the relative distance between the vehicle 2 (own vehicle) and the vehicle 3 (other vehicle). Therefore, the shorter the relative distance between the vehicle 2 (own vehicle) and the vehicle 3 (other vehicle), the larger (better) the vehicle quality value of the vehicle 3 becomes. The shorter the interval between the vehicle 2 (own vehicle), the same traveling direction as the vehicle 2 (own vehicle), and the same vehicle speed as the vehicle 2 (own vehicle), the shorter the relative distance becomes. Since such a vehicle 3 (other vehicle) can maintain a state in which the interval between the vehicle 2 (own vehicle) and the vehicle 2 (own vehicle) is short, the inter-vehicle communication path 120 of the vehicle 3 (other vehicle) continues to be stably established between the vehicle 2 (own vehicle). Therefore, by using the inter-vehicle communication path 120 of the vehicle 3 (other vehicle) for the multi-route communication of the vehicle 2, subflow switching by the vehicle 3 is suppressed, and the multi-route communication of the vehicle 2 can be continued stably.

[0086] Moreover, the wireless communication paths 110 of the vehicles 3 and 2 included in the subflow list 22 are subflows whose line quality values ​​exceed a predetermined threshold and provide good line quality. By using such subflows for the multiple-path communication of the vehicle 2, the multiple-path communication of the vehicle 2 can be continued stably.

[0087] As described above, according to this embodiment, by performing multi-route communication using multiple subflows included in the subflow list 22, it is possible to improve the quality of the multi-route communication, such as the continuity and stability.

[0088] [Second embodiment] Fig. 7 is a block diagram showing a configuration example of a communication relay device according to this embodiment. The communication relay device 30a shown in Fig. 7 has a configuration almost similar to that of the communication relay device 30 in Fig. 3, but a communication status list 41 is stored in the storage unit 35. The communication system 1 and the communication device 10 have the same configuration as those in Figs. 1 and 2.

[0089] The control unit 34 of the communication relay device 30a uses the communication status list 41 to manage the relayed communication volume (relayed communication volume) for each vehicle 2 (other vehicle) to which the vehicle 3 relays communication. The control unit 34 determines whether or not to relay communication based on the relayed communication volume.

[0090] For example, the control unit 34 records the relay communication volume per unit time for each vehicle 2 (vehicle ID) in the communication status list 41. When the total value of the relay communication volume per unit time exceeds a predetermined threshold, the control unit 34 does not allow relaying of new communications to other vehicles 2 for a certain period of time. Furthermore, when the total value of the relay communication volume per unit time exceeds the predetermined threshold and then is equal to or less than the predetermined threshold for the certain period of time, the control unit 34 allows relaying of new communications. The control unit 34 may manage the total value of the relay communication volume and determine whether or not to relay a communication based on the total value of the relay communication volume. For example, the control unit 34 records the total value of the relay communication volume per unit time in the communication status list 41 without distinguishing between vehicles 2, and does not allow relaying of a new communication when the total value of the relay communication volume per unit time exceeds a predetermined threshold. In this case, the control unit 34 allows relaying of a new communication when the total value of the relay communication volume per unit time is equal to or less than the predetermined threshold for a certain period of time after the total value of the relay communication volume per unit time exceeds the predetermined threshold.

[0091] When the wireless communication unit 32 of the communication relay device 30a can use multiple wireless communication networks, the control unit 34 measures the line quality for each of the multiple wireless communication networks. Based on the measurement results of the line quality of the multiple wireless communication networks, the control unit 34 determines which of the multiple wireless communication networks to use to relay the communication of the vehicle 2 (other vehicle). For example, the wireless communication network with the best line quality among the multiple wireless communication networks available to the wireless communication unit 32 is used to relay the communication of the vehicle 2 (other vehicle).

[0092] The control unit 34 of the communication relay device 30a may prioritize communication of an application installed in the vehicle 3 over relaying communication of the vehicle 2 (other vehicle).

[0093] The control unit 34 of the communication relay device 30a may occupy the communication path of its own vehicle 3 (own vehicle) by its own vehicle. As an occupancy method, for example, the control unit 34 does not transmit vehicle information of its own vehicle by the vehicle-to-vehicle communication unit 31. This prevents the vehicle 2 (other vehicle) from recognizing the presence of its own vehicle, and prevents relaying of communication from the vehicle 2 (other vehicle).

[0094] The control unit 34 of the communication relay device 30a may create the above-mentioned sub-flow list 22 and transmit a "shut down message" to other vehicles registered in its own sub-flow list 22 via the vehicle-to-vehicle communication unit 31. The vehicle 2 that receives the "Shut down message" deletes the vehicle 3 that sent the "Shut down message" from the other vehicle candidate list 21.

[0095] Next, the overall procedure of the multiple-route communication method according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a sequence diagram showing an example of the overall procedure of the multiple-route communication method according to this embodiment.

[0096] (Step S61) The communication relay device 30a of the vehicle 3 broadcasts the vehicle information of the vehicle 3 through vehicle-to-vehicle communication.

[0097] (Step S62) When the communication device 10 of the vehicle 2 receives the vehicle information broadcast by vehicle-to-vehicle communication from the vehicle 3, it updates the other vehicle candidate list 21. The method of updating the other vehicle candidate list is the same as in the first embodiment described above. This will be explained later.

[0098] (Step S63) The communication device 10 of the vehicle 2 requests the vehicles 3 included in the other vehicle candidate list 21 to confirm whether the line is available.

[0099] (Step S64) The communication relay device 30a of the vehicle 3 determines whether or not to relay the communication based on the relayed communication volume in the communication status list 41 for the vehicle 2 that has requested confirmation of the availability of the line.

[0100] (Step S65) The communication relay device 30a of the vehicle 3 responds to the vehicle 2 that has requested the confirmation of line availability with the result of the determination in step S64 as to whether the subflow can be used. If the result of the determination in step S64 is that communication relay is possible, the communication relay device 30a responds that the subflow can be used, and if the result of the determination in step S64 is that communication relay is not possible, the communication relay device 30a responds that the subflow cannot be used.

[0101] (Step S66) The communication device 10 in the vehicle 2 transmits a subflow request to the vehicle 3 that has responded that the subflow can be used.

[0102] (Step S67) The communication relay device 30a in the vehicle 3 adds to the communication status list 41 a new communication relay item for the vehicle 2 that is the source of the subflow request.

[0103] (Step S68) The communication device 10 in the vehicle 2 measures the quality of the line via the inter-vehicle communication path 120 for the vehicle 3 that is the destination of the subflow request.

[0104] (Step S69) Based on the result of the line quality measurement in step S68, the communication device 10 in the vehicle 2 updates the sub-flow list 22. The method of updating the sub-flow list is the same as in the first embodiment described above.

[0105] (Step S70) The communication device 10 of the vehicle 2 performs multi-route communication using a plurality of subflows included in the subflow list 22. For example, multi-route communication is performed using a plurality of inter-vehicle communication paths 120 included in the subflow list 22. For example, multi-route communication is performed using the wireless communication path 110 and one or a plurality of inter-vehicle communication paths 120 included in the subflow list 22.

[0106] According to this embodiment, it is possible to improve the quality of the multi-route communication, such as the continuity and stability, as in the above-described first embodiment. Furthermore, according to this embodiment, it is possible to control whether or not to relay the communication in the vehicle 3 that relays the communication of the other vehicle.

[0107] According to each of the above-described embodiments, it is possible to obtain an effect of improving the quality, such as the continuity and stability, of multi-route communication.

[0108] This will, for example, make it possible to improve the overall service quality in wireless networks, thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0109] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present invention are also included.

[0110] In the above-described embodiment, the communication device 10 and the communication relay devices 30 and 30a are separately mounted in the vehicle 2 and the vehicle 3, respectively, but the communication device 10 and the communication relay devices 30 and 30a may be mounted in the same vehicle.

[0111] In the above embodiment, the communication device 10 and the communication relay devices 30 and 30a are configured separately, but the communication device 10 and the communication relay devices 30 and 30a may be configured as a single device.

[0112] In addition, a computer program for implementing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. Note that the "computer system" referred to here may include hardware such as an OS and peripheral devices. In addition, the term "computer-readable recording medium" refers to writable non-volatile memory such as a flexible disk, an optical magnetic disk, a ROM, or a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into a computer system.

[0113] Furthermore, the term "computer-readable recording medium" includes devices that retain a program for a certain period of time, such as volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may be transmitted from a computer system in which the program is stored in a storage device or the like to another computer system via a transmission medium, or by a transmission wave in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for implementing some of the functions described above, or may be a so-called differential file (differential program) that can implement the functions described above in combination with a program already recorded in the computer system. [Explanation of symbols]

[0114] 1... communication system, 2, 3... vehicle, 4... server, 10... communication device, 11, 31... vehicle-to-vehicle communication unit, 12, 32... wireless communication unit, 13... multiple route communication unit, 14, 34... control unit, 15, 35... storage unit, 21... other vehicle candidate list, 22... subflow list, 30, 30a... communication relay device, 33... communication relay unit, 41... communication status list, NWa, NWb... wireless communication network, NWc... Internet

Claims

1. In a communication device mounted on a vehicle, A vehicle-to-vehicle communication unit that performs vehicle-to-vehicle communication with another vehicle; a wireless communication unit that connects to a wireless communication network and performs wireless communication; a multiple-route communication unit that performs multiple-route communication using multiple communication routes simultaneously; a control unit that selects a plurality of communication paths to be simultaneously used for the multi-route communication from among an other-vehicle communication path that is a communication path via the vehicle-to-vehicle communication and a vehicle communication path that is a communication path of the wireless communication; Equipped with The control unit is calculating a vehicle quality value indicating a quality of an other-vehicle communication route of the other vehicle based on the vehicle information of the other vehicle received through the vehicle-to-vehicle communication; selecting a plurality of communication paths to be simultaneously used for the multiple path communication based on the vehicle quality value; The vehicle information is vehicle speed, direction of travel, and position information. Communications equipment.

2. The vehicle information of the other vehicle includes information indicating a position, a speed, and a traveling direction of the other vehicle, the vehicle quality value indicates a relative distance between the vehicle and another vehicle, When selecting a plurality of communication routes to be used simultaneously for the multi-route communication, the control unit selects from among an other-vehicle communication route, which is a communication route via the vehicle-to-vehicle communication only between other vehicles whose relative distance is less than a predetermined threshold, and the own-vehicle communication route. The communication device according to claim 1 .

3. A communication device mounted on a vehicle, A vehicle-to-vehicle communication unit that performs vehicle-to-vehicle communication with another vehicle; a wireless communication unit that connects to a wireless communication network and performs wireless communication; a multiple-route communication unit that performs multiple-route communication using multiple communication routes simultaneously; a control unit that selects a plurality of communication paths to be simultaneously used for the multi-route communication from among an other-vehicle communication path that is a communication path via the vehicle-to-vehicle communication and a vehicle communication path that is a communication path of the wireless communication; Equipped with The vehicle information of the other vehicle includes communication carrier information indicating a carrier of a wireless communication network used by the other vehicle, When selecting a plurality of communication routes to be used simultaneously in the multi-route communication, the control unit selects from among the host vehicle communication route, which is a communication route between the host vehicle and only another vehicle having different communication carrier information from the host vehicle, via the vehicle-to-vehicle communication, and the host vehicle communication route. Communications equipment.

4. The control unit is creating a candidate other vehicle list, which is a list of other vehicles that are candidates for communication routes used in the multiple route communication, based on the vehicle quality value; Measure the line quality when using the other-vehicle communication path of the other vehicle included in the other-vehicle candidate list; selecting a plurality of communication paths to be used in the multiple-path communication based on the measurement results of the line quality; A communication device according to claim 1 or 2.

5. In a communication relay device mounted on a vehicle, a vehicle-to-vehicle communication unit that performs vehicle-to-vehicle communication with another vehicle equipped with the communication device according to any one of claims 1 to 4; a wireless communication unit that connects to a wireless communication network and performs wireless communication; a communication relay unit that relays communication between an other-vehicle communication path that is a communication path for the inter-vehicle communication and a vehicle communication path that is a communication path for the wireless communication; A control unit that controls relay of the communication, The control unit transmits vehicle information of the vehicle through the vehicle-to-vehicle communication. Communications relay device.

6. The control unit manages a total value of relay communication volume, and determines whether or not to relay the communication based on the total value of relay communication volume. The communication relay device according to claim 5.

7. the wireless communication unit is capable of using a plurality of wireless communication networks; The control unit is measuring line quality for each of the plurality of wireless communication networks; determining which of the plurality of wireless communication networks is to be used to relay the communication based on the measurement result of the line quality; The communication relay device according to claim 5 or 6.

8. a vehicle-to-vehicle communication step in which a communication device mounted on the vehicle performs vehicle-to-vehicle communication with another vehicle; a wireless communication step in which the communication device connects to a wireless communication network and performs wireless communication; a multiple-route communication step in which the communication device performs multiple-route communication using multiple communication routes simultaneously; a control step of selecting, by the communication device, a plurality of communication paths to be simultaneously used for the multi-path communication from among an other-vehicle communication path that is a communication path via the inter-vehicle communication and a vehicle communication path that is a communication path of the wireless communication; Including, The control step includes: calculating a vehicle quality value indicating a quality of an other-vehicle communication route of the other vehicle based on the vehicle information of the other vehicle received through the vehicle-to-vehicle communication; selecting a plurality of communication paths to be simultaneously used for the multiple path communication based on the vehicle quality value; The vehicle information is vehicle speed, direction of travel, and position information. Communication methods.

9. A vehicle-to-vehicle communication step in which a communication device mounted on a vehicle performs vehicle-to-vehicle communication with another vehicle; a wireless communication step in which the communication device connects to a wireless communication network and performs wireless communication; a multiple-route communication step in which the communication device performs multiple-route communication using multiple communication routes simultaneously; a control step of selecting, by the communication device, a plurality of communication paths to be simultaneously used for the multi-path communication from among an other-vehicle communication path that is a communication path via the inter-vehicle communication and a vehicle communication path that is a communication path of the wireless communication; Including, The vehicle information of the other vehicle includes communication carrier information indicating a carrier of a wireless communication network used by the other vehicle, In the control step, when selecting a plurality of communication routes to be used simultaneously in the multi-route communication, a communication route is selected from among the own vehicle communication route, which is a communication route between the own vehicle and only another vehicle having different communication carrier information from the own vehicle, and the own vehicle communication route. Communication methods.

10. a vehicle-to-vehicle communication step in which a communication relay device mounted on a vehicle performs vehicle-to-vehicle communication with another vehicle mounted with the communication device according to any one of claims 1 to 4; a wireless communication step in which the communication relay device connects to a wireless communication network and performs wireless communication; a communication relay step in which the communication relay device relays communication between an other-vehicle communication path that is a communication path for the inter-vehicle communication and a vehicle communication path that is a communication path for the wireless communication; a control step of controlling relay of the communication by the communication relay device, In the control step, the communication relay device transmits vehicle information of the vehicle through the vehicle-to-vehicle communication. Communication relay method.

11. A computer program for causing a computer of a communication device mounted on a vehicle to execute the communication method described in any one of claims 8 or 9.

12. A computer program for causing a computer of a communication relay device mounted on a vehicle to execute the communication relay method described in claim 10.

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