Road side unit, control device, on-board unit, system, method, and program

Abstract

Provided is a road side unit, a control device, an on-board unit, a system, a method, and a program that enable communication between on-board units having different communication schemes. The system comprises a first RSU, a second RSU, a first OBU, and a second OBU. The first RSU comprises: a reception part that receives a message from the first OBU in a first communication scheme for inter-device direct communication; and a transfer part that transfers the received message to the second RSU that can communicate with the second OBU in a second communication scheme for inter-device direct communication.

Description

Roadside unit, control device, on-board unit, system, method, and program

[0001] The present disclosure relates to a roadside device, a control device, an in-vehicle device, a system, a method, and a program.

[0002] The communication technology that connects vehicles with various things is called V2X (Vehicle to Everything). V2X includes vehicle-to-vehicle communication between an on-board unit (OBU) installed in a vehicle and an on-board unit installed in another vehicle, and road-to-vehicle communication between an on-board unit and a roadside unit (RSU) installed on the roadside.

[0003] A related technology, Dedicated Short Range Communication (DSRC), based on the IEEE 802.11p standard, which began in the 2000s, has been introduced on a small scale in the United States and Japan. The Long Term Evolution-V2X (LTE-V2X) standard, introduced in 3GPP (Third Generation Partnership Project) (registered trademark) Release 14, incorporates the latest technology and offers superior performance to DSRC. The 5G standard, New Radio V2X (NR-V2X), was standardized in 3GPP Release 16 and continues to this day. LTE-V2X and NR-V2X are sometimes referred to as Cellular V2X (C-V2X). C-V2X includes a PC5 interface for direct wireless communication between vehicles or between roads and vehicles (Device-to-Device communication / Side Link communication), and a Uu interface for mobile communication between vehicles and base stations.

[0004] For example, Patent Document 1 describes that IP packets are transmitted and received between an LTE UE (on-board device) and a DSRC UE (on-board device) via an LTE evolved Node B (eNB) and a WLAN access point (AP).

[0005] U.S. Pat. No. 1,064,057

[0006] In Patent Document 1, communication between an LTE UE and a DSRC UE using different communication methods is possible by passing the communication from the LTE UE through an eNB. However, Patent Document 1 assumes the use of a Uu interface for communication between a terminal and a base station, and does not take into consideration the use of a PC5 interface for direct communication between devices. As a result, communication may not be possible between in-vehicle devices using different communication methods.

[0007] In view of such problems, one of the objects of the present disclosure is to provide a roadside unit, a control device, an on-board unit, a system, a method, and a program that enable communication between on-board units that use different communication methods.

[0008] A roadside device according to one aspect of the present disclosure includes means for receiving a message from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and means for forwarding the received message to another roadside device that can communicate with the second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0009] A roadside device according to one aspect of the present disclosure includes means for receiving, from another roadside device, a message that the other roadside device has received from a first vehicle-mounted device using a first communication method for direct device-to-device communication and forwarded, and means for transmitting the received message to a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0010] A control device according to one aspect of the present disclosure includes a means for receiving, from a first roadside device, a message that the first roadside device has received from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and a means for transferring the received message to another control device connected to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0011] A control device according to one aspect of the present disclosure includes means for receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and means for transmitting the received message to a second roadside device capable of communicating with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0012] An in-vehicle device according to one aspect of the present disclosure includes means for acquiring information about a first roadside device from a first roadside device using a first communication method for direct communication between devices, and means for notifying a second roadside device of the acquired information about the first roadside device using the first communication method or a second communication method.

[0013] A system according to one aspect of the present disclosure is a system including a first roadside device and a second roadside device, wherein the first roadside device includes means for receiving a message from a first vehicle-mounted device using a first communication method for device-to-device direct communication, and means for forwarding the received message to the second roadside device that can communicate with the second vehicle-mounted device using a second communication method for device-to-device direct communication, and the second roadside device includes means for receiving from the first roadside device a message that the first roadside device received and forwarded from the first vehicle-mounted device using the first communication method, and means for transmitting the received message to the second vehicle-mounted device using the second communication method.

[0014] A method according to one aspect of the present disclosure is a method for a roadside device, comprising receiving a message from a first vehicle-mounted device using a first communication method for device-to-device direct communication, and forwarding the received message to another roadside device that can communicate with the second vehicle-mounted device using a second communication method for device-to-device direct communication.

[0015] A method according to one aspect of the present disclosure is a method for a roadside device, and includes receiving, from the other roadside device, a message that the other roadside device has received from a first vehicle-mounted device and forwarded using a first communication method for device-to-device direct communication, and transmitting the received message to a second vehicle-mounted device using a second communication method for device-to-device direct communication.

[0016] A method according to one aspect of the present disclosure is a method for a control device, and includes receiving from a first roadside device a message that the first roadside device received from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and forwarding the received message to another control device connected to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0017] A method according to one aspect of the present disclosure is a method for a control device, and includes receiving a message received by a first roadside device from a first vehicle-mounted device using a first communication method for direct device-to-device communication, from another control device connected to the first roadside device, and transmitting the received message to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0018] A method according to one aspect of the present disclosure is a method for an in-vehicle device, and includes acquiring information about a first roadside device from a first roadside device using a first communication method for direct communication between devices, and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or a second communication method.

[0019] A program according to one aspect of the present disclosure is a program for causing a computer to execute a method for a roadside device, the method including receiving a message from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and forwarding the received message to another roadside device that can communicate with the second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0020] A program according to one aspect of the present disclosure is a program for causing a computer to execute a method for a roadside device, the method including receiving from the other roadside device a message that the other roadside device has received from a first vehicle-mounted device and forwarded using a first communication method for device-to-device direct communication, and transmitting the received message to a second vehicle-mounted device using a second communication method for device-to-device direct communication.

[0021] A program according to one aspect of the present disclosure is a program for causing a computer to execute a method for a control device, the method including receiving from a first roadside device a message that the first roadside device received from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and forwarding the received message to another control device connected to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0022] A program according to one aspect of the present disclosure is a program for causing a computer to execute a method for a control device, the method including receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first vehicle-mounted device using a first communication method for direct device-to-device communication, and transmitting the received message to a second roadside device capable of communicating with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

[0023] A program according to one aspect of the present disclosure is a program for causing a computer to execute a method for an on-board device, the method including acquiring information about a first roadside device from a first roadside device using a first communication method for direct communication between devices, and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or a second communication method.

[0024] According to the present disclosure, communication can be performed between in-vehicle devices that use different communication methods.

[0025] FIG. 1 is a block diagram illustrating an example configuration of a system according to some embodiments. FIG. 2 is a block diagram illustrating an example configuration of a first RSU according to some embodiments. FIG. 3 is a block diagram illustrating an example configuration of a second RSU according to some embodiments. FIG. 4 is a block diagram illustrating an example configuration of a first OBU according to some embodiments. FIG. 5 is a block diagram illustrating an example configuration of a second OBU according to some embodiments. FIG. 6 is a block diagram illustrating an example configuration of a first control device according to some embodiments. FIG. 7 is a block diagram illustrating an example configuration of a second control device according to some embodiments. FIG. 8 is a block diagram illustrating an example basic configuration of a wireless communication system according to some embodiments. FIG. 9 is a block diagram for explaining issues in the example basic configuration of a wireless communication system according to some embodiments. FIG. 10 is a block diagram illustrating an example configuration of a wireless communication system according to some embodiments. FIG. 11 is a block diagram illustrating an example configuration of a DSRC RSU according to some embodiments. FIG. 12 is a block diagram illustrating an example configuration of a C-V2X RSU according to some embodiments. FIG. 13 is a block diagram illustrating an example configuration of a DSRC OBU according to some embodiments. FIG. 14 is a diagram illustrating an example format of a BSM according to some embodiments. FIG. 15 is a block diagram illustrating an example configuration of a C-V2X OBU according to some embodiments. FIG. 16 is a diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 17 is a diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 18 is a flowchart illustrating an example operation of an RSU under forwarding policy 1 according to some embodiments. FIG. 1 illustrates an example of BSM forwarding under forwarding policy 1 according to some embodiments. FIG. 2 is a flowchart illustrating an example of RSU operation under forwarding policy 2 according to some embodiments. FIG. 3 is a flowchart illustrating an example of RSU operation under forwarding policy 3 according to some embodiments. FIG. 4 illustrates an example of BSM forwarding under forwarding policy 3 according to some embodiments. FIG. 5 is a block diagram illustrating an example configuration of a wireless communication system according to some embodiments. FIG. 6 is a block diagram illustrating an example configuration of a dual RSU according to some embodiments. FIG. 7 illustrates an example operation of a wireless communication system according to some embodiments. FIG. 8 illustrates an example operation of a wireless communication system according to some embodiments.FIG. 1 is a block diagram illustrating an example configuration of a wireless communication system according to some embodiments. FIG. 2 is a block diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 3 is a block diagram illustrating an example configuration of a wireless communication system according to some embodiments. FIG. 4 is a block diagram illustrating an example configuration of a DSRC control device according to some embodiments. FIG. 5 is a block diagram illustrating an example configuration of a C-V2X control device according to some embodiments. FIG. 6 is a block diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 7 is a block diagram illustrating an example configuration of a wireless communication system according to some embodiments. FIG. 8 is a block diagram illustrating an example configuration of a control device according to some embodiments. FIG. 9 is a sequence diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 10 is a block diagram illustrating an example configuration of a dual OBU according to some embodiments. FIG. 11 is a block diagram illustrating an example configuration of an RSU according to some embodiments. FIG. 12 is a block diagram illustrating an example operation of a wireless communication system according to some embodiments. FIG. 13 is a block diagram illustrating an example configuration of a DSRC OBU according to some embodiments. FIG. 14 is a block diagram illustrating an example configuration of a C-V2X OBU according to some embodiments. FIG. 15 is a block diagram illustrating an example configuration of a hardware of a control device according to some embodiments. FIG. 16 is a block diagram illustrating an example configuration of a hardware of an RSU according to some embodiments. FIG. 17 is a block diagram illustrating an example configuration of a hardware of an OBU according to some embodiments.

[0026] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted as necessary.

[0027] (Embodiment 1) First, embodiment 1 will be described. In this embodiment, an outline of several embodiments will be described.

[0028] FIG. 1 illustrates an example configuration of a system 1 according to some embodiments. The system 1 is a wireless communication system that performs wireless communication between an RSU (roadside unit) and an OBU (on-board unit). For example, the system 1 may be an ITS (Intelligence Transport System). In the system 1, for example, the OBUs notify each other of the current positions of the vehicles, thereby understanding the status of surrounding vehicles and ensuring driving safety.

[0029] The example of FIG. 1 includes RSUs 10 (10a and 10b in this example) and OBUs 20 (20a and 20b in this example). For example, RSU 10a will be referred to as the first RSU and RSU 10b will be referred to as the second RSU, but either RSU may be the first RSU or the second RSU. For example, either RSU 10a or RSU 10b may be simply referred to as the RSU, and the other may be referred to as the other RSU. Also, OBU 20a will be referred to as the first OBU and OBU 20b will be referred to as the second OBU, but either OBU may be the first OBU or the second OBU. For example, either OBU 20a or OBU 20b may be simply referred to as the OBU, and the other may be referred to as the other OBU. The number of RSUs 10 and OBUs 20 in FIG. 1 is an example and is not limited thereto.

[0030] The first RSU 10a and the second RSU 10b are terminal devices installed on the side of the road. The first OBU 20a and the second OBU 20b are terminal devices mounted on vehicles. The first RSU 10a and the first OBU 20a are capable of wireless communication using a first communication method for direct device-to-device communication. The second RSU 10b and the second OBU 20b are capable of wireless communication using a second communication method for direct device-to-device communication. Direct device-to-device communication is a communication method in which direct communication is performed between terminals including an OBU and an RSU without going through a base station. Since the first communication method and the second communication method are different communication methods, the first OBU 20a and the second OBU 20b cannot communicate directly. For example, one of the first and second communication methods is DSRC and the other is C-V2X PC5, but other communication methods may also be used. Also, the first RSU 10a and the second RSU 10b can communicate via any interface (transmission path).

[0031] 2 shows an example configuration of a first RSU 10a according to some embodiments. In the example of Fig. 2, the first RSU 10a includes a receiving unit 11 and a forwarding unit 12. For example, the first RSU 10a is a single RSU capable of communication using a first communication method, but may also be a dual RSU capable of communication using both the first and second communication methods.

[0032] The receiver 11 receives a message from the first OBU 20a using a first communication method for direct communication between devices. The message may be a message that reports information about the vehicle in which the first OBU 20a is installed. For example, the message may be a Basic Safety Message (BSM) that includes information such as the vehicle's location, or may be another message. The first RSU 10a may also include a transmitter that transmits a message using the first communication method. For example, the first RSU 10a may transmit a BSM or the like, similar to the second RSU 10b.

[0033] The transfer unit 12 transfers the message received by the receiving unit 11 to the second RSU 10b. That is, the transfer unit 12 transfers the message received from the first OBU 20a in the first communication method for device-to-device direct communication to the second RSU 10b that can communicate with the second OBU 20b in the second communication method for device-to-device direct communication via an arbitrary interface.

[0034] The forwarding unit 12 may forward the received message as is, or may forward the message according to a predetermined forwarding policy. For example, the forwarding unit 12 may forward the received message as is when the receiving unit 11 receives the message. For example, the forwarding policy may include a policy for forwarding a message based on the distance between the first OBU 20 a and the second RSU 10 b, a policy for forwarding a message according to a priority based on the vehicle type of the first OBU 20 a or the type of message, a policy for controlling the frequency of message forwarding, etc.

[0035] For example, the first OBU 20a may store forwarding information (neighbor relationship table) indicating a forwarding relationship (neighbor relationship) with the second OBU 20b, and the forwarding unit 12 may forward the message to the second OBU 20b based on the stored forwarding information. The information on the second OBU 20b included in the forwarding information may be acquired from a control device that controls the first OBU 20a and the second OBU 20b, or may be acquired from the first OBU 20a.

[0036] 3 shows an example configuration of a second RSU 10b according to some embodiments. In the example of Fig. 3, the second RSU 10b includes a receiving unit 13 and a transmitting unit 14. For example, the second RSU 10b is a single RSU capable of communicating using the second communication method, but may also be a dual RSU capable of communicating using the first communication method and the second communication method.

[0037] The receiving unit 13 receives a message transferred from the first RSU 10 a. That is, the receiving unit 13 receives, from the first RSU 10 a, a message that the first RSU 10 a has received and transferred using the first communication method for direct communication between devices, via an arbitrary interface.

[0038] The transmitter 14 transmits the message received by the receiver 13 to the second OBU 20b using a second communication method for device-to-device direct communication. For example, the transmitter 14 may notify the received message, such as a BSM. This allows the message transmitted by the first OBU 20a using the first communication method to be transmitted to the second OBU 20b using the second communication method. Note that the second RSU 10b may receive the message, such as a BSM, using the second communication method.

[0039] Note that one RSU may include the functions of the first RSU 10a and the second RSU 10b. For example, the first RSU 10a and the second RSU 10b may each include the receiving unit 11 and the forwarding unit 12 in Fig. 2 and the receiving unit 13 and the transmitting unit 14 in Fig. 3. A message transmitted from the first OBU 20a may be forwarded to the second OBU 20b via the first RSU 10a and the second RSU 10b, or a message transmitted from the second OBU 20b may be forwarded to the first OBU 20a via the second RSU 10b and the first RSU 10ba.

[0040] Fig. 4 shows an example configuration of the first OBU 20a according to some embodiments. In the example of Fig. 4, the first OBU 20a includes a transmitter 21 and a receiver 22. For example, the first OBU 20a is a single OBU capable of communicating using a first communication method.

[0041] The transmitter 21 transmits a message to the first RSU 10 a using a first communication method for direct communication between devices. For example, the transmitter 21 may broadcast a message such as a BSM including information about the vehicle in which the first OBU 20 a is installed.

[0042] The receiving unit 22 receives a message from the first RSU 10 a using a first communication method for direct communication between devices. For example, when another OBU 20 transmits a message such as a BSM using the first communication method, the receiving unit 22 may receive the transmitted message.

[0043] For example, the first OBU 20a may transmit, to the first RSU 10a, information about the second RSU 10b that is necessary for the first RSU 10a to transfer a message. For example, if the first OBU 20a is a dual OBU, an acquisition unit (e.g., the receiving unit 22) may acquire information about the second RSU 10b from the second RSU 10b using the second communication method, and a notification unit (e.g., the transmitting unit 21) may notify the first RSU 10a using the first communication method. For example, if the first RSU 10a and the second RSU 10b are dual RSUs, an acquisition unit (e.g., the receiving unit 22) may acquire information about the second RSU 10b from the second RSU 10b using the first communication method, and a notification unit (e.g., the transmitting unit 21) may notify the first RSU 10a using the first communication method.

[0044] Fig. 5 shows an example configuration of the second OBU 20b according to some embodiments. In the example of Fig. 5, the second OBU 20b includes a receiving unit 23 and a transmitting unit 24. For example, the second OBU 20b is a single OBU capable of communicating using the second communication method.

[0045] The receiver 23 receives a message from the second RSU 10b using a second communication method for device-to-device direct communication. That is, the receiver 23 receives a message such as a BSM transmitted from the first OBU 20a using the first communication method from the second RSU 10b. For example, when another OBU 20 transmits a message such as a BSM using the second communication method, the receiver 23 may receive the transmitted message.

[0046] The transmitter 24 transmits a message to the second RSU 10b using a second communication method for direct communication between devices. For example, the transmitter 24 may broadcast a message such as a BSM including information about the vehicle equipped with the second OBU 20b, similar to the first OBU 20a.

[0047] Note that messages may be transferred directly between the first RSU 10a and the second RSU 10b, or may be transferred via other devices, such as control devices that control the first RSU 10a and the second RSU 10b. Examples of the respective control devices when messages are transferred by the first control device 30a and the second control device 30b are shown in Figures 6 and 7.

[0048] 6 illustrates an example configuration of a first control device 30a according to some embodiments. For example, the first control device 30a is a control device that controls the first RSU 10a. In the example of FIG. 6, the first control device 30a includes a receiving unit 31 and a transferring unit 32.

[0049] The receiving unit 31 receives a message transferred from the first RSU 10 a. That is, the receiving unit 31 receives from the first RSU 10 a a message that the first RSU 10 a received from the first OBU 20 a using the first communication method for direct communication between devices.

[0050] The transfer unit 32 transfers the message received by the receiving unit 31 to the second control device 30b. That is, the transfer unit 32 transfers the received message to the second control device 30b connected to the second RSU 10b that can communicate with the second OBU 20b using the second communication method for direct communication between devices.

[0051] 7 illustrates an example configuration of the second control device 30b according to some embodiments. For example, the second control device 30b is a control device that controls the second RSU 10b. In the example of FIG. 7, the second control device 30b includes a receiving unit 33 and a transmitting unit 34.

[0052] The receiving unit 33 receives a message transferred from the first control device 30a. That is, the receiving unit 33 receives, from the first control device 30a connected to the first RSU 10a, a message that the first RSUa received from the first OBU 20a using the first communication method for direct communication between devices.

[0053] The transmitter 34 transmits the message received by the receiver 33 to the second RSU 10b. That is, the transmitter 34 transmits the message received from the first control device 30a to the second RSU 10b that can communicate with the second OBU 20b using the second communication method for direct communication between devices.

[0054] As described above, in this embodiment, OBU messages using different communication methods are transferred between the first RSU and the second RSU. Communication can be performed between an OBU that communicates using a first communication method for device-to-device direct communication, such as DSRC, and an OBU that communicates using a second communication method for device-to-device direct communication, such as C-V2X PC5.

[0055] (Embodiment 2) In embodiment 2 and subsequent embodiments, a specific example of embodiment 1 will be described. In embodiment 2, an example of transferring an OBU message between a DSRC RSU and a C-V2X RSU will be described.

[0056] 8 shows an example of a basic configuration of a wireless communication system 2 according to some embodiments. In the example of FIG. 8, the wireless communication system 2 includes a DSRC RSU 100a, a C-V2X RSU 100b, a DSRC OBU 200a (200a-1 and 200a-2 in this example), and a C-V2X OBU 200b (200b-1 and 200b-2 in this example). Note that either or both of the DSRC RSU 100a and the C-V2X RSU 100b may be simply referred to as RSU 100. Either or both of the DSRC OBU 200a and the C-V2X OBU 200b may be simply referred to as OBU 200.

[0057] The DSRC RSU 100a and the C-V2X RSU 100b are terminal devices installed on the side of the road. The DSRC RSU 100a and the C-V2X RSU 100b are terminal devices capable of wireless communication using the DSRC system and the C-V2X PC5 system, respectively, and do not have base station functionality. The DSRC RSU 100a and the C-V2X RSU 100b may be dedicated RSU devices or may be mounted on various types of equipment installed around the road. For example, the DSRC RSU 100a and the C-V2X RSU 100b may be mounted on traffic lights, road lights, toll gates including ETC (Electronic Toll Collection System) gates on expressways, various signboards around the road, power transmission-related steel towers, steel towers for camera observation, bus stop sign poles, mobile base stations, various radio stations, etc.

[0058] The DSRC OBU 200a and the C-V2X OBU 200b are terminal devices mounted on vehicles. For example, the vehicle may be various types of automobiles, trains, mobile robots, etc., but may also be other moving objects. For example, the vehicle may be a land moving object such as a bicycle or a motorcycle, a water moving object such as a ship or a water boat taxi, an underwater moving object not limited to water, or an aerial moving object (aircraft) such as an airplane, a drone, or an urban air mobility (UAM) including an air taxi.

[0059] The DSRC RSU 100a and the DSRC OBU 200a are DSRC terminals capable of wireless communication using the DSRC system (DSRC interface). Direct wireless communication using the DSRC system is possible between the DSRC OBU 200a-1 and the DSRC OBU 200a-2 (vehicle-to-vehicle). Direct wireless communication using the DSRC system is also possible between the DSRC RSU 100a and each of the DSRC OBUs 200a-1 and 200a-2 (road-to-vehicle). For example, by transmitting and receiving a BSM including vehicle position information and the like between the DSRC OBU 200a-1 and the DSRC OBU 200a-2, the positions of surrounding vehicles and the like can be mutually ascertained.

[0060] The C-V2X RSU 100b and the C-V2X OBU 200b are C-V2X PC5 terminals capable of wireless communication using the C-V2X PC5 system (PC5 interface). Direct wireless communication is possible between the C-V2X OBU 200b-1 and the C-V2X OBU 200b-2 (vehicle-to-vehicle) using the C-V2X PC5 system. Direct wireless communication is also possible between the C-V2X RSU 100b and each of the C-V2X OBUs 200b-1 and 200b-2 (road-to-vehicle) using the C-V2X PC5 system. As with the DSRC OBU 200a, for example, the C-V2X OBU 200b-1 and the C-V2X OBU 200b-2 can mutually determine the positions of surrounding vehicles by transmitting and receiving BSMs containing vehicle position information, etc.

[0061] 9 illustrates a problem in a basic configuration example of a wireless communication system 2 according to some embodiments. As described in FIG. 8, the DSRC RSU 100a and DSRC OBUs 200a-1 and 200a-2, which are DSRC-compatible and use the same communication method, can communicate with each other. Also, the C-V2X RSU 100b and C-V2X OBUs 200b-1 and 200b-2, which are C-V2X PC5-compatible and use the same communication method, can communicate with each other.

[0062] However, the DSRC system and the C-V2X PC5 system are completely incompatible. As a result, no communication can be performed between DSRC OBUs 200a-1 and 200a-2 and C-V2X OBUs 200b-1 and 200b-2 (vehicle-to-vehicle). DSRC OBU 200a cannot receive BSMs from C-V2X OBU 200b, and therefore cannot identify surrounding C-V2X OBU 200b vehicles. C-V2X OBU 200b cannot receive BSMs from DSRC OBU 200a, and therefore cannot identify surrounding DSRC OBU 200a vehicles.

[0063] For example, a method of replacing all DSRC-compatible systems with C-V2X-compatible systems is conceivable, but this may require replacing hardware rather than upgrading software, which would be extremely expensive. Incompatible and compatible inter-vehicle communications may coexist in the same location, which may hinder the realization of efficient inter-vehicle communications. Therefore, in this embodiment, communication is enabled between a DSRC OBU and a C-V2X PC5 OBU.

[0064] FIG. 10 shows an example configuration of a wireless communication system 3 according to some embodiments. In the example of FIG. 10, based on the configurations of FIGS. 8 and 9, the DSRC RSU 100a and the C-V2X RSU 100b are communicatively connected via an inter-RSU interface 4 to enable communication between them. The DSRC RSU 100a and the C-V2X RSU 100b may be installed in the same area, for example, in adjacent locations. The inter-RSU interface 4 may be any interface that allows communication between the RSUs 100. For example, the inter-RSU interface 4 may be an IP interface such as Ethernet (registered trademark) that can send and receive IP packets. In this embodiment, between the DSRC RSU 100a and the C-V2X RSU 100b, the BSM from each OBU is transferred to an RSU using a different communication method via the inter-RSU interface 4.

[0065] Fig. 11 shows an example configuration of a DSRC RSU 100a according to some embodiments. In the example of Fig. 11, the DSRC RSU 100a includes a DSRC communication unit 101, a C-V2X inter-RSU communication unit 102, a transfer unit 103, and a storage unit 104. The configuration of Fig. 11 is just one example, and other configurations may be used as long as the DSRC RSU 100a according to some embodiments can operate.

[0066] The DSRC RSU 100a may also have other functions required as an RSU or a roadside system. For example, the DSRC RSU 100a may have a function for acquiring various information, such as the status of traffic lights and road lights, from traffic lights and road lights, and a function for notifying an ITS system server of information about traffic lights, road lights, and surrounding vehicles. Furthermore, multiple functions included in the DSRC RSU 100a may be implemented by a single device or multiple devices. The multiple devices constituting the DSRC RSU 100a may be located in the same place or in different places. The devices constituting the DSRC RSU 100a may include physical devices (computers) or virtual machines running on a virtualization platform. The same applies to the C-V2X RSU 100b.

[0067] The DSRC communication unit 101 performs wireless communication with surrounding DSRC terminals (e.g., DSRC OBU 200a) using the DSRC system. The DSRC communication unit 101 transmits and receives higher layer messages included in the DSRC signal by transmitting and receiving DSRC-based wireless signals (DSRC signals) defined by IEEE 802.11p. The transmitted and received messages are, for example, broadcast messages such as BSM, but may also be other messages. For example, the DSRC communication unit 101 receives messages such as BSM broadcast from surrounding DSRC terminals including the DSRC OBU 200a, and broadcasts messages such as BSM to surrounding DSRC terminals including the DSRC OBU 200a.

[0068] The C-V2X inter-RSU communication unit 102 communicates with the C-V2X RSU 100b via the inter-RSU interface 4. For example, if the inter-RSU interface 4 is an IP interface, the C-V2X inter-RSU communication unit 102 transmits and receives IP packets containing messages such as BSMs via the inter-RSU interface 4. For example, the C-V2X inter-RSU communication unit 102 receives IP packets containing messages such as BSMs sent from the C-V2X RSU 100b to the DSRC RSU 100a, and also transmits IP packets containing messages such as BSMs to the C-V2X RSU 100b.

[0069] The transfer unit 103 controls the transfer of messages between the DSRC communication unit 101 and the C-V2X inter-RSU communication unit 102. For example, the transfer unit 103 controls messages such as BSMs received by the DSRC communication unit 101 from the DSRC OBU 200a to be transmitted from the C-V2X inter-RSU communication unit 102 to the C-V2X RSU 100b, and also controls messages such as BSMs received by the C-V2X inter-RSU communication unit 102 from the C-V2X RSU 100b to be transmitted from the DSRC communication unit 101 to the DSRC OBU 200a.

[0070] The storage unit 104 stores a neighbor relationship table including RSUs (neighbor RSUs) in the vicinity of the DSRC RSU 100a. The neighbor relationship table is a table that registers neighbor relationships (forwarding relationships) with neighboring RSUs. The neighbor relationship table includes RSU information (neighbor RSU information) necessary for message forwarding for each neighbor RSU (forwarding destination RSU). RSUs registered in the neighbor relationship table are RSUs (neighbor RSUs) that have a neighbor relationship. For example, the neighbor RSU information includes the RSU's communication method, location information, IP (Internet Protocol) address, etc. In this example, the neighbor relationship table stores information about the C-V2X RSU 100b as neighbor RSU information. The forwarding unit 103 refers to the neighbor relationship table in the storage unit 104 and forwards the message to the C-V2X RSU 100b based on the neighbor RSU information registered in the neighbor relationship table.

[0071] Fig. 12 shows an example configuration of a C-V2X RSU 100b according to some embodiments. In the example of Fig. 12, the C-V2X RSU 100b includes a C-V2X communication unit 111, a DSRC inter-RSU communication unit 112, a transfer unit 113, and a storage unit 114. The configuration of Fig. 12 is just an example, and other configurations may be used as long as the C-V2X RSU 100b according to some embodiments can operate.

[0072] The C-V2X communication unit 111 performs wireless communication with surrounding C-V2X PC5 terminals (e.g., C-V2X OBU 200b) using the C-V2X PC5 method. The C-V2X communication unit 111 transmits and receives higher layer messages included in the sidelink signals by transmitting and receiving radio signals (sidelink signals) using the C-V2X PC5 method defined by 3GPP. The transmitted and received messages are, for example, broadcast messages such as BSMs, but may also be other messages. For example, the C-V2X communication unit 111 receives messages such as BSMs broadcast from surrounding C-V2X PC5 terminals including the C-V2X OBU 200b, and broadcasts messages such as BSMs to surrounding C-V2X PC5 terminals including the C-V2X OBU 200b.

[0073] The DSRC inter-RSU communication unit 112 communicates with the DSRC RSU 100a via the inter-RSU interface 4. For example, if the inter-RSU interface 4 is an IP interface, the DSRC inter-RSU communication unit 112 transmits and receives IP packets containing messages such as BSMs via the inter-RSU interface 4. For example, the DSRC inter-RSU communication unit 112 receives messages such as BSMs sent from the DSRC RSU 100a to the C-V2X RSU 100b, and also transmits messages such as BSMs to the DSRC RSU 100a.

[0074] The transfer unit 113 controls the transfer of messages between the C-V2X communication unit 111 and the DSRC RSU communication unit 112. For example, the transfer unit 113 controls messages such as a BSM that the C-V2X communication unit 111 receives from the C-V2X OBU 200b to be transmitted from the DSRC RSU inter-RSU communication unit 112 to the DSRC RSU 100a, and also controls messages such as a BSM that the DSRC RSU inter-RSU communication unit 112 receives from the DSRC RSU 100a to be transmitted from the C-V2X communication unit 111 to the C-V2X OBU 200b.

[0075] Similar to the memory unit 104 of the DSRC RSU 100a, the memory unit 114 stores a neighbor relation table including RSUs (neighbor RSUs) in the vicinity of the C-V2X RSU 100b. In this example, the neighbor relation table stores information about the DSRC RSU 100a as neighbor RSU information. The forwarding unit 113 refers to the neighbor relation table in the memory unit 114 and forwards a message to the DSRC RSU 100a based on the neighbor RSU information registered in the neighbor relation table.

[0076] Fig. 13 shows an example of the configuration of a DSRC OBU 200a according to some embodiments. In the example of Fig. 13, the DSRC OBU 200a includes a DSRC communication unit 201, a vehicle information acquisition unit 202, and a message processing unit 203. The configuration of Fig. 13 is just an example, and other configurations may be used as long as the DSRC OBU 200a according to some embodiments can operate.

[0077] The DSRC OBU 200a may also have other functions required as an OBU or an in-vehicle system. For example, the DSRC OBU 200a may have a function of outputting message information received from the DSRC RSU 100a or another DSRC OBU 200a to a vehicle navigation device. Furthermore, multiple functions included in the DSRC OBU 200a may be realized by one device or multiple devices. The same applies to the C-V2X OBU 200b.

[0078] The DSRC communication unit 201 performs wireless communication with surrounding DSRC terminals (e.g., the DSRC RSU 100a and other DSRC OBUs 200a) using the DSRC method. The DSRC communication unit 201 transmits and receives higher-layer messages included in the DSRC signal by transmitting and receiving DSRC-based wireless signals (DSRC signals) defined by IEEE 802.11p. The transmitted and received messages are, for example, broadcast messages such as BSMs, but may also be other messages. For example, the DSRC communication unit 201 receives messages such as BSMs broadcast from surrounding DSRC terminals including the DSRC RSU 100a and other DSRC OBUs 200a, and broadcasts messages such as BSMs to surrounding DSRC terminals including the DSRC RSU 100a and other DSRC OBUs 200a.

[0079] The vehicle information acquisition unit 202 acquires vehicle information of the vehicle in which the DSRC OBU 200a is installed. The vehicle information is information necessary for messages such as BSM, and includes, for example, the vehicle's position, speed, direction, acceleration, etc. For example, the vehicle information acquisition unit 202 may acquire the vehicle's position information from a GPS (Global Positioning System) receiver installed in the vehicle, or may acquire the position information by other methods. The vehicle information acquisition unit 202 may acquire the vehicle's speed, direction, acceleration, etc. from an ECU (Electronic Control Unit) installed in the vehicle, etc. The vehicle information acquisition unit 202 may acquire video of the vehicle's surroundings from a camera installed in the vehicle.

[0080] The message processing unit 203 processes messages transmitted and received by the DSRC communication unit 201. The messages are messages defined in the upper layer of DSRC (WAVE: Wireless Access in Vehicular Environment), such as BSM, but may also be other messages.

[0081] FIG. 14 illustrates an example format of a BSM according to some embodiments. For example, the BSM format is defined in SAE International J2945 / 1 and J3161 / 1. In the example of FIG. 14, the BSM includes a core data element section and an extension section. The core data element section includes a temporary ID (which may be an OBU ID), a sequence number, a timestamp of the position correction, the position, the speed / direction, the acceleration, the vehicle length / width, the brake system status, etc. The extension section can include various information as needed, such as a critical event flag, vehicle light status, a route prediction, and route history points. For example, the BSM format may be the same for both the DSRC system and the C-V2X PC5 system.

[0082] The message processing unit 203 generates a BSM based on the information acquired by the vehicle information acquisition unit 202 and transmits the generated BSM from the DSRC communication unit 201. For example, the BSM is transmitted 10 times per second (at 0.1 second intervals). The message processing unit 203 may generate a message including, in addition to the BSM, a camera image or the like and transmit the message from the DSRC communication unit 201. The message processing unit 203 may perform necessary processing in response to a message such as a BSM received by the DSRC communication unit 201. For example, the message processing unit 203 may determine the positions of surrounding vehicles from the position information included in the received BSM and output the information to a navigation device or the like. For example, a collision with another vehicle may be avoided based on the information included in the received BSM. For example, autonomous driving may be realized based on the information included in the received BSM.

[0083] Fig. 15 shows an example configuration of a C-V2X OBU 200b according to some embodiments. In the example of Fig. 15, the C-V2X OBU 200b includes a C-V2X communication unit 211, a vehicle information acquisition unit 202, and a message processing unit 203. The configuration of Fig. 15 is just an example, and other configurations may be used as long as the C-V2X OBU 200b according to some embodiments can operate.

[0084] The C-V2X communication unit 211 performs wireless communication with surrounding C-V2X PC5 terminals (e.g., the C-V2X RSU 100b or another C-V2X OBU 200b) using the C-V2X PC5 method. The C-V2X communication unit 211 transmits and receives higher layer messages included in the sidelink signal by transmitting and receiving radio signals (sidelink signals) using the C-V2X PC5 method defined by 3GPP. The messages transmitted and received are, for example, broadcast messages such as BSMs, but may also be other messages. For example, the C-V2X communication unit 211 receives messages such as BSM broadcast from C-V2X PC5 terminals including the surrounding C-V2X RSU 100b and other C-V2X OBU 200b, and also broadcasts messages such as BSM to the surrounding C-V2X PC5 terminals including the surrounding C-V2X RSU 100b and other C-V2X OBU 200b.

[0085] The vehicle information acquisition unit 202 and message processing unit 203 are the same as those of the DSRC OBU 200a. That is, the vehicle information acquisition unit 202 acquires vehicle information of the vehicle in which the C-V2X OBU 200b is installed. The message processing unit 203 processes messages such as BSMs transmitted and received by the C-V2X communication unit 211.

[0086] 16 and 17 show examples of operation of the wireless communication system 3 according to some embodiments. Fig. 16 shows an example in which a BSM from the DSRC OBU 200a is transferred from the DSRC RSU 100a to the C-V2X RSU 100b. Fig. 17 shows an example in which a BSM from the C-V2X OBU 200b is transferred from the C-V2X RSU 100b to the DSRC RSU 100a.

[0087] 16, the DSRC OBU 200a-1 transmits a BSM in the DSRC system (S101). The DSRC OBU 200a-1 broadcasts a BSM including information such as the location of its own vehicle to its surroundings in the DSRC system. For example, if the DSRC OBU 200a-2 is located within the wireless communication range of the DSRC OBU 200a-1, the DSRC OBU 200a-2 can receive the BSM from the DSRC OBU 200a-1.

[0088] Next, the DSRC RSU 100a transfers the BSM from the DSRC OBU 200a-1 to the C-V2X RSU 100b (S102). The DSRC RSU 100a receives the BSM from the DSRC OBU 200a-1 using the DSRC method and transmits the received BSM to the C-V2X RSU 100b via the inter-RSU interface 4. For example, the DSRC RSU 100a obtains the IP address of the C-V2X RSU 100b from the neighbor relation table and transmits an IP packet including the BSM to the obtained IP address.

[0089] Next, the C-V2X RSU 100b transmits the BSM from the DSRC RSU 100a in the C-V2X PC5 format (S103). For example, the C-V2X RSU 100b receives an IP packet containing a BSM sent from the DSRC RSU 100a to the C-V2X RSU 100b via the inter-RSU interface 4. The C-V2X RSU 100b broadcasts the BSM contained in the received IP packet to its surroundings as a C-V2X PC5 format message. Then, the C-V2X OBUs 200b-1 and 200b-2 receive the BSM from the C-V2X RSU 100b in the C-V2X PC5 format. This allows the C-V2X OBUs 200b-1 and 200b-2 to ascertain the position of the DSRC OBU 200a-1, etc.

[0090] 17, the C-V2X OBU 200b-1 transmits a BSM in the C-V2X PC5 format (S111). The C-V2X OBU 200b-1 broadcasts a BSM including information such as the location of its own vehicle to its surroundings in the C-V2X PC5 format. For example, if the C-V2X OBU 200b-2 is located within the wireless communication range of the C-V2X OBU 200b-1, the C-V2X OBU 200b-2 can receive the BSM from the C-V2X OBU 200b-1.

[0091] Next, the C-V2X RSU 100b transfers the BSM from the C-V2X OBU 200b-1 to the DSRC RSU 100a (S112). The C-V2X RSU 100b receives the BSM from the C-V2X OBU 200b-1 using the C-V2X PC5 method and transmits the received BSM to the DSRC RSU 100a via the inter-RSU interface 4. For example, the C-V2X RSU 100b obtains the IP address of the DSRC RSU 100a from the neighbor relationship table and transmits an IP packet including the BSM to the obtained IP address.

[0092] Next, the DSRC RSU 100a transmits the BSM from the C-V2X RSU 100b in the DSRC method (S113). For example, the DSRC RSU 100a receives an IP packet containing a BSM transmitted from the C-V2X RSU 100b to the DSRC RSU 100a via the inter-RSU interface 4. The DSRC RSU 100a broadcasts the BSM contained in the received IP packet to its surroundings as a DSRC message. Then, the DSRC OBUs 200a-1 and 200a-2 receive the BSM from the DSRC RSU 100a in the DSRC method. This allows the DSRC OBUs 200a-1 and 200a-2 to ascertain the location of the C-V2X OBU 200b-1, etc.

[0093] As described above, in this embodiment, the DSRC RSU forwards the BSM received from the DSRC OBU to the C-V2X RSU, and the C-V2X RSU transmits the BSM received from the DSRC RSU to the C-V2X OBU. Similarly, the C-V2X RSU forwards the BSM received from the C-V2X OBU to the DSRC RSU, and the DSRC RSU transmits the BSM received from the C-V2X RSU to the DSRC OBU. This allows messages such as BSMs to be transmitted and received via the DSRC RSU and C-V2X RSU between the DSRC OBU and C-V2X OBU, which cannot communicate directly.

[0094] (Third Embodiment) Next, a third embodiment will be described. In this embodiment, an example of a transfer policy for transferring an OBU message between a DSRC RSU and a C-V2X RSU will be described. Note that the configuration of the wireless communication system and the configuration of each device according to this embodiment are the same as those in the second embodiment.

[0095] In this embodiment, the RSU 100 (DSRC RSU 100a, C-V2X RSU 100b) forwards messages such as BSMs received from the OBU 200 in accordance with a predetermined forwarding policy. For example, because a BSM is transmitted from the OBU 200 10 times per second, an increase in the number of OBUs 200 results in a huge amount of BSMs being forwarded, increasing the processing load on the RSU 100 itself and the forwarding load between the RSUs 100. Therefore, the RSU 100 forwards BSMs in accordance with a forwarding policy to reduce the load on the RSU 100 and the inter-RSU interface. For example, if the processing load of the RSU 100 at the forwarding source is greater than a predetermined value or if the forwarding load of the inter-RSU interface is greater than a predetermined value, the BSMs to be forwarded may be filtered according to the forwarding policy. Here, forwarding policies 1 to 3 are described as an example. Note that forwarding policies 1 to 3 may be combined as necessary. Furthermore, other policies may be used in addition to forwarding policies 1 to 3. The forwarding policy may include a policy for forwarding a message containing information about a vehicle that is highly relevant to the destination RSU based on the vehicle's direction of movement. That is, when multiple neighbor RSUs are registered, the destination RSU may be selected from the multiple RSUs based on the vehicle's direction of movement. For example, the RSU 100 may obtain the vehicle's direction of movement from the received BSM and select an RSU that is included in (or close to) the vehicle's movement area estimated from the obtained movement direction as the destination RSU. The movement area may be estimated from the vehicle's movement direction, speed, acceleration, etc.

[0096] <Forwarding Policy 1> Forwarding policy 1 is a policy that controls whether or not to forward a message based on distance. Specifically, it controls the forwarding of a BSM based on the distance between the OBU that sent the BSM and the RSU that is the destination of the BSM.

[0097] 18 illustrates an example of the operation of the RSU 100 under forwarding policy 1 according to some embodiments. The process in FIG. 18 is performed, for example, by the forwarding unit 103 of the DSRC RSU 100a and the forwarding unit 113 of the C-V2X RSU 100b.

[0098] 18 , the RSU 100 receives a BSM from a surrounding OBU 200 (S201). Next, the RSU 100 calculates the distance D of the OBU 200 that transmitted the BSM (S202). The distance D is the distance from the OBU 200 that transmitted the BSM to the RSU 100 (an RSU with a neighbor relationship). For example, the distance D is calculated based on the location information of the OBU 200 included in the received BSM and the location information of the RSU 100 that is included in the neighbor relationship table.

[0099] Next, the RSU 100 compares the calculated distance D with a predetermined threshold Dt (S203) and, depending on the comparison result, forwards the BSM (S204) or discards the BSM (S205). For example, if the distance D is smaller than the threshold Dt (short distance), the RSU 100 forwards the BSM received from the OBU 200 to a neighboring RSU 100. On the other hand, if the distance D is equal to or greater than the threshold Dt (long distance), the RSU 100 discards and does not forward the BSM received from the OBU 200. When the distance between OBUs is large, there is little need for vehicle information about the other OBU. When forwarding a BSM, the location of the OBU that will ultimately receive the BSM is unknown, so the distance between the location of the transmitting OBU and the location of the destination RSU is used as the forwarding criterion. For example, if there are multiple RSUs 100 with neighbor relationships, the BSM is forwarded to RSUs 100 whose distance D is smaller than a threshold Dt, and the BSM is not forwarded to RSUs 100 whose distance D is equal to or greater than the threshold Dt.

[0100] Figure 19 shows a specific example of BSM forwarding under forwarding policy 1 according to some embodiments. In the example of Figure 19, wireless communication system 3 includes DSRC RSU 100a, DSRC OBU 200a, C-V2X RSUs 100b-1 and 100b-2, and C-V2X OBUs 200b-1 to 200b-5.

[0101] DSRC OBU 200a is located within the wireless communication range of DSRC RSU 100a. C-V2X OBUs 200b-1 and 200b-2 are located within the wireless communication range of C-V2X RSU 100b-1. C-V2X OBUs 200b-3 to 200b-5 are located within the wireless communication range of C-V2X RSU 100b-2.

[0102] For example, if the DSRC RSU 100a is the local station, the neighbor RSUs around the local station are the C-V2X RSUs 100b-1 and 100b-2. In other words, the DSRC RSU 100a and the C-V2X RSU 100b-1 mutually transfer BSMs, and the DSRC RSU 100a and the C-V2X RSU 100b-2 mutually transfer BSMs.

[0103] For example, when the C-V2X RSU 100b-2 receives a BSM from the C-V2X OBU 200b-3, the distance D between the C-V2X OBU 200b-3 and the DSRC RSU 100a is shorter than the threshold Dt, so the C-V2X RSU 100b-2 forwards the received BSM to the DSRC RSU 100a. That is, the C-V2X RSU 100b-2 determines that the BSM needs to be forwarded to a DSRC OBU 200a in the vicinity of the DSRC RSU 100a. For example, the predetermined threshold Dt is the distance between the DSRC RSU 100a and the C-V2X RSU 100b-2. For example, the predetermined threshold Dt may be set based on external factors such as traffic congestion information or weather information. The value of the threshold Dt may be increased when there is traffic congestion, and decreased when the traffic congestion is resolved. The value of the threshold Dt may be decreased when the weather is bad, and increased when the weather is good.

[0104] Furthermore, when the C-V2X RSU 100b-2 receives a BSM from the C-V2X OBU 200b-4, the distance D between the C-V2X OBU 200b-4 and the DSRC RSU 100a is greater than the threshold Dt, so the C-V2X RSU 100b-2 discards the received BSM and does not forward it to the DSRC RSU 100a. In other words, it determines that there is no need to forward the BSM to the DSRC OBUs 200a surrounding the DSRC RSU 100a.

[0105] <Transfer Policy 2> Transfer policy 2 is a policy that controls whether or not to transfer a message based on priority. Specifically, the transfer of a BSM is controlled based on the priority according to the information in the BSM.

[0106] 20 illustrates an example of the operation of the RSU 100 in forwarding policy 2 according to some embodiments. The process in FIG. 20 is performed, for example, by the forwarding unit 103 of the DSRC RSU 100a and the forwarding unit 113 of the C-V2X RSU 100b.

[0107] In the example of FIG. 20 , the RSU 100 receives a BSM from a surrounding OBU 200 (S201). Next, the RSU 100 determines a priority P for transferring the BSM (S211). For example, the RSU 100 determines the priority P based on information included in the BSM. If the BSM includes a vehicle type (e.g., emergency vehicle, general vehicle), the priority may be determined based on the vehicle type acquired from the BSM. The vehicle type may be set in the critical event flag of the BSM or may be newly added to the BSM. For example, a high priority may be set for an emergency vehicle, and a low priority may be set for a general vehicle. If the BSM includes a message urgency, the priority may be determined based on the urgency acquired from the BSM. The message urgency may be set in the critical event flag of the BSM. Furthermore, when transferring a message other than a BSM, the priority may be determined based on the message type. For example, a high priority may be set for a BSM, and a low priority may be set for an application data message transmitting camera footage, for example.

[0108] Next, the RSU 100 compares the identified priority D with a predetermined threshold Pt (S212), and depending on the comparison result, forwards the BSM (S204) or discards the BSM (S205). For example, if the priority P is greater than the threshold Pt (high priority), the RSU 100 forwards the BSM received from the OBU to a neighboring RSU 100. If the priority P is equal to or less than the threshold Pt (low priority), the RSU 100 discards the BSM received from the OBU and does not forward it.

[0109] Figure 21 shows a specific example of BSM transfer under transfer policy 2 according to some embodiments. In the example of Figure 21, wireless communication system 3 includes DSRC RSU 100a, DSRC OBU 200a, C-V2X RSUs 100b-1 and 100b-2, and C-V2X OBUs 200b-1 to 200b-6. DSRC OBU 200a is located within the wireless communication range of DSRC RSU 100a.

[0110] C-V2X OBUs 200b-1 to 200b-3 are located within a wireless communication range of the C-V2X RSU 100b-1. For example, the vehicle of C-V2X OBU 200b-1 is an emergency vehicle, the vehicle of C-V2X OBU 200b-2 is a general vehicle, and the vehicle of C-V2X OBU 200b-3 is a large vehicle.

[0111] C-V2X OBUs 200b-4 to 200b-6 are located within the wireless communication range of the C-V2X RSU 100b-2. For example, the vehicle of C-V2X OBU 200b-4 is a general vehicle, the vehicle of C-V2X OBU 200b-5 is an ambulance, and the vehicle of C-V2X OBU 200b-6 is a fire engine.

[0112] For example, if the DSRC RSU 100a is the local station, the neighbor RSUs around the local station are the C-V2X RSUs 100b-1 and 100b-2. In other words, the DSRC RSU 100a and the C-V2X RSU 100b-1 mutually transfer BSMs, and the DSRC RSU 100a and the C-V2X RSU 100b-2 mutually transfer BSMs.

[0113] Furthermore, the priority of ordinary vehicles is P2, the priority of large vehicles is P3, the priority of emergency vehicles is P4, the priority of emergency vehicles and fire engines is P7, and the threshold value Pt is P3.

[0114] For example, when the C-V2X RSU 100b-1 receives a BSM from the C-V2X OBU 200b-1, the priority P4 of the vehicle (emergency vehicle) of the C-V2X OBU 200b-1 is greater than the threshold Pt, so the C-V2X RSU 100b-1 forwards the received BSM to the DSRC RSU 100a. When the C-V2X RSU 100b-1 receives BSMs from the C-V2X OBU 200b-2 and the C-V2X OBU 200b-3, the priority P2 of the vehicle (ordinary vehicle) of the C-V2X OBU 200b-2 and the priority P3 of the vehicle (large vehicle) of the C-V2X OBU 200b-3 are equal to or less than the threshold Pt, so the C-V2X RSU 100b-1 discards the received BSM and does not forward it to the DSRC RSU 100a.

[0115] Furthermore, when the C-V2X RSU 100b-2 receives a BSM from the C-V2X OBU 200b-4, it discards the received BSM and does not forward it to the DSRC RSU 100a because the priority P2 of the vehicle (general vehicle) of the C-V2X OBU 200b-4 is equal to or lower than the threshold Pt. When the C-V2X RSU 100b-2 receives BSMs from the C-V2X OBU 200b-5 and the C-V2X OBU 200b-6, it forwards the received BSM to the DSRC RSU 100a because the priority P7 of the vehicle (emergency vehicle) of the C-V2X OBU 200b-5 and the priority P7 of the vehicle (fire engine) of the C-V2X OBU 200b-6 are greater than the threshold Pt.

[0116] <Transfer Policy 3> Transfer Policy 3 is a policy that controls the frequency of message transfer. While Transfer Policies 1 and 2 determine whether or not to transfer a BSM based on distance and priority, Transfer Policy 3 changes the frequency (interval) at which BSMs are transferred.

[0117] Fig. 22 shows an example of the operation of the RSU 100 when forwarding policy 3 is used in some embodiments. Fig. 22 shows an example in which forwarding policy 1 is combined with forwarding policy 3, but forwarding policy 2 may also be combined with forwarding policy 3. The processing in Fig. 22 is performed, for example, by the forwarding unit 103 of the DSRC RSU 100a and the forwarding unit 113 of the C-V2X RSU 100b.

[0118] In the example of Fig. 22, similar to Fig. 18, the RSU 100 receives a BSM from a surrounding OBU 200 (S201) and calculates the distance D (S202). Next, the RSU 100 compares the calculated distance D with a threshold Dt (S203). If the distance D is smaller than the threshold Dt, the RSU 100 forwards the BSM received from the OBU 200 to a neighboring RSU 100 (S204). The RSU 100 forwards the BSM transmitted from the OBU 200 10 times per second without modification. In other words, the RSU 100 forwards the BSMs received 10 times per second (at 0.1 second intervals) at the same timing.

[0119] Furthermore, if the distance D is equal to or greater than the threshold value Dt, the RSU 100 controls the transfer frequency of the received BSM (S206). The RSU 100 reduces the transfer frequency of the BSM to less than 10 times per second and transfers it to neighboring RSUs 100. For example, the transfer frequency may be once per second or once per 10 seconds. In this case, the RSU 100 stores the BSM received from the OBU 200 in a memory unit and transfers the BSM at a frequency of once per second to once per 10 seconds based on the information of the stored BSM. The transfer frequency (interval) may be changed according to the distance D. For example, the transfer frequency may be decreased as the distance D increases. Note that when transfer is controlled according to priority, the transfer frequency may be changed according to the priority. For example, the transfer frequency may be decreased as the priority decreases.

[0120] When the transmission frequency is reduced, the accumulated BSM information may be averaged. For example, if a BSM is transmitted once per second, the average values ​​of the vehicle's position, speed, direction, acceleration, etc. contained in the multiple BSMs received in one second may be calculated, a BSM including the calculated average value may be generated, and the generated BSM may be transmitted. The accumulated BSM information may also be resampled. For example, if a BSM is transmitted once every 10 seconds, one BSM may be sampled (selected) from the BSMs received in the 10 seconds and transmitted. For example, a BSM received in the middle of the 10 seconds (around 5 seconds) may be transmitted. For example, the most recent BSM of the multiple BSMs received in the 10 seconds may be transmitted.

[0121] Figure 23 shows a specific example of BSM forwarding in forwarding policy 3 according to some embodiments. In the example of Figure 23, wireless communication system 3 includes DSRC RSU 100a, DSRC OBU 200a, C-V2X RSUs 100b-1 and 100b-2, and C-V2X OBUs 200b-1 and 200b-2.

[0122] The DSRC OBU 200a is located within the wireless communication range of the DSRC RSU 100a. The C-V2X OBU 200b-1 moves within the wireless communication range of the C-V2X RSU 100b-1. The C-V2X OBU 200b-2 moves within the wireless communication range of the C-V2X RSU 100b-2.

[0123] If the DSRC RSU 100a is the local station, the neighbor RSUs around the local station are the C-V2X RSUs 100b-1 and 100b-2. In other words, BSMs are transferred between the DSRC RSU 100a and the C-V2X RSU 100b-1, and BSMs are transferred between the DSRC RSU 100a and the C-V2X RSU 100b-2.

[0124] For example, if the C-V2X RSU 100b-1 receives BSMs from the C-V2X OBU 200b-1 at a frequency of 10 times per second, it reduces the transmission frequency of the received BSMs to once per second (1 Hz) based on distance and priority, and transmits the BSMs to the DSRC OBU 200a. In this case, for example, if the speed included in the BSM received at t=0.1 s is 85 km / h, the speed included in the BSM received at t=0.2 s is 80 km / h, and the speed included in the BSM received at t=0.9 s is 90 km / h, the C-V2X RSU 100b-1 calculates the average of these speeds and transmits a BSM including the calculated average value (e.g., 80 km / h) to the DSRC OBU 200a.

[0125] Furthermore, if the C-V2X RSU 100b-2 receives BSMs from the C-V2X OBU 200b-2 at a frequency of 10 times per second, it reduces the transmission frequency of the received BSMs to once every 10 seconds (0.1 Hz) based on distance and priority, and transmits the BSMs to the DSRC OBU 200a. At this time, for example, if the speed included in the BSM received at t=1 s is 85 km / h, the speed included in the BSM received at t=2 s is 80 km / h, and the speed included in the BSM received at t=9 s is 90 km / h, the C-V2X RSU 100b-2 resamples (selects) the 80 km / h at t=2 s and transmits the BSM including 80 km / h to the DSRC OBU 200a.

[0126] As described above, in this embodiment, when the RSU forwards messages such as BSMs received from the OBU, the amount of messages to be forwarded is controlled according to a forwarding policy. For example, forwarding may be controlled according to the distance of the OBU or the priority of the message, or the forwarding frequency may be controlled. This reduces the amount of messages forwarded by the RSU and the load on forwarding.

[0127] (Fourth Embodiment) Next, a fourth embodiment will be described. In this embodiment, an example will be described in which an OBU message is transferred between a dual RSU that is compatible with or conforms to both the DSRC system and the C-V2X PC5 system, and a single RSU that is compatible with or conforms to the DSRC system or the C-V2X PC5 system.

[0128] Fig. 24 shows a configuration example of a wireless communication system 3 according to some embodiments. In the example of Fig. 24, the wireless communication system 3 includes a C-V2X RSU 100b and a dual RSU 100c as RSUs. Note that the RSU is not limited to the C-V2X RSU 100b, and a DSRC RSU 100a may also be included. The other configurations are the same as those in Fig. 10.

[0129] The dual RSU 100c is an RSU capable of communicating in both the DSRC system and the C-V2X PC5 system. In this example, the dual RSU 100c and the C-V2X RSU 100b (single RSU) are connected to each other via the inter-RSU interface 4 so that they can communicate with each other.

[0130] 25 illustrates an example configuration of a dual RSU 100c according to some embodiments. The dual RSU 100c has the functionality of the dual RSU 100c and the functionality of the C-V2X RSU 100b.

[0131] 25, the DUAL RSU 100c, like the DSRC RSU 100a, includes a DSRC communication unit 101, a C-V2X inter-RSU communication unit 102, a transfer unit 103, and a storage unit 104, and like the C-V2X RSU 100b, includes a C-V2X communication unit 111, a DSRC inter-RSU communication unit 112, a transfer unit 113, and a storage unit 114. For example, the transfer unit 103 and the transfer unit 113 may be a single block. The storage unit 104 and the storage unit 114 may be a single block.

[0132] Similar to the DSRC RSU 100a, the storage unit 104 stores a neighbor relation table including information about the C-V2X RSU 100b as neighbor RSU information. The forwarding unit 103 forwards messages received from the DSRC OBU 200a to the C-V2X RSU 100b based on the neighbor RSU information in the neighbor relation table of the storage unit 104. The forwarding unit 103 also transmits messages received from the C-V2X RSU 100b to the DSRC OBU 200a.

[0133] Similar to the C-V2X RSU 100b, the storage unit 114 stores a neighbor relation table including information about the DSRC RSU 100a as neighbor RSU information. The forwarding unit 113 forwards messages received from the C-V2X OBU 200b to the DSRC RSU 100a based on the neighbor RSU information in the neighbor relation table of the storage unit 114. The forwarding unit 113 also transmits messages received from the DSRC RSU 100a to the C-V2X OBU 200b.

[0134] 26 and 27 show examples of operation of the wireless communication system 3 according to some embodiments. FIG. 26 shows an example in which a BSM from the DSRC OBU 200a is transferred from the DUAL RSU 100c to the C-V2X RSU 100b. The same applies to the case in which a BSM from the C-V2X RSU 100b is transferred from the DUAL RSU 100c to the DSRC RSU 100a. FIG. 27 shows an example in which a BSM from the C-V2X OBU 200b is transferred from the C-V2X RSU 100b to the DUAL RSU 100c. The same applies to the case in which a BSM from the DSRC OBU 200a is transferred from the DSRC RSU 100a to the DUAL RSU 100c.

[0135] In the example of Fig. 26, the operations other than those of the dual RSU 100c are the same as those of Fig. 16. That is, the DSRC OBU 200a-1 transmits a BSM in the DSRC system (S301).

[0136] Next, the DUAL RSU 100c transmits the BSM from the DSRC OBU 200a-1 in the C-V2X PC5 format (S302) and transfers it to the C-V2X RSU 100b (S303). Steps S302 and S303 may be executed in parallel, or one of them may be executed first.

[0137] For example, the DUAL RSU 100c (DSRC communication unit 101) receives a BSM from the DSRC OBU 200a-1 using the DSRC method. The DUAL RSU 100c (C-V2X communication unit 111) broadcasts the received BSM to the surrounding area using the C-V2X PC5 method. This allows the C-V2X OBU 200b-2 to receive the BSM from the DUAL RSU 100c using the C-V2X PC5 method and determine the location of the DSRC OBU 200a-1, etc.

[0138] The dual RSU 100c may further transmit the BSM from the DSRC OBU 200a-1 using the DSRC method. For example, if the DSRC OBU 200a-2 is located outside the wireless communication range of the DSRC OBU 200a-1 but within the wireless communication range of the dual RSU 100c, the DSRC OBU 200a-2 can receive the BSM from the dual RSU 100c using the DSRC method and determine the location of the DSRC OBU 200a-1.

[0139] Furthermore, the DUAL RSU 100c (C-V2X inter-RSU communication unit 102) transmits the BSM received from the DSRC OBU 200a-1 to the C-V2X RSU 100b via the inter-RSU interface 4. For example, the DUAL RSU 100c obtains the IP address of the C-V2X RSU 100b from the neighbor relation table in the storage unit 104, and transmits an IP packet including the BSM to the obtained IP address.

[0140] Next, the C-V2X RSU 100b transmits the BSM from the DUAL RSU 100c in the C-V2X PC5 format (S304). As a result, the C-V2X OBU 200b-1 receives the BSM from the C-V2X RSU 100b in the C-V2X PC5 format and can ascertain the position of the DSRC OBU 200a-1, etc.

[0141] In the example of Fig. 27, the operations other than those of the dual RSU 100c are the same as those of Fig. 17. That is, the C-V2X OBU 200b-1 transmits a BSM in the C-V2X PC5 method (S311).

[0142] Next, the C-V2X RSU 100b transfers the BSM from the C-V2X OBU 200b-1 to the DUAL RSU 100c (S312). The C-V2X RSU 100b receives the BSM from the C-V2X OBU 200b-1 using the C-V2X PC5 method and transmits the received BSM to the DUAL RSU 100a via the inter-RSU interface 4. For example, the C-V2X RSU 100b obtains the IP address of the DUAL RSU 100c from the neighbor relationship table and transmits an IP packet including the BSM to the obtained IP address.

[0143] Next, the DUAL RSU 100c transmits the BSM from the C-V2X RSU 100b using the DSRC method (S313). For example, the DUAL RSU 100c (C-V2X inter-RSU communication unit 102) receives an IP packet containing a BSM sent from the C-V2X RSU 100b to the DUAL RSU 100c via the inter-RSU interface 4. The DUAL RSU 100c (DSRC communication unit 101) broadcasts the BSM contained in the received IP packet to its surroundings as a DSRC message. This allows the DSRC OBUs 200a-1 and 200a-2 to receive the BSM from the DUAL RSU 100c using the DSRC method and determine the location of the C-V2X OBU 200b-1, etc.

[0144] The DUAL RSU 100c may further transmit the BSM received from the C-V2X RSU 100b using the C-V2X PC5 method. For example, if the C-V2X OBU 200b-2 is located outside the wireless communication range of the C-V2X OBU 200b-1 but within the wireless communication range of the DUAL RSU 100c, the C-V2X OBU 200b-2 can receive the BSM from the DUAL RSU 100c using the C-V2X PC5 method and determine the location of the C-V2X OBU 200b-1.

[0145] As described above, in this embodiment, the BSM of the OBU is transferred between the dual RSU and the single RSU. Even in this case, messages such as the BSM can be transmitted and received between the DSRC OBU and the C-V2X OBU via the dual RSU and the single RSU.

[0146] (Embodiment 5) Next, a description will be given of embodiment 5. In this embodiment, an example will be described in which an OBU message is transferred between dual RSUs that are compatible with both the DSRC system and the C-V2X PC5 system.

[0147] Fig. 28 shows an example configuration of a wireless communication system 3 according to some embodiments. In the example of Fig. 28, the wireless communication system 3 includes dual RSUs 100c-1 and 100c-2 as RSUs. Other configurations are the same as those in Fig. 24. Furthermore, the configurations of the dual RSUs 100c-1 and 100c-2 are the same as those in Fig. 25.

[0148] In the example of Figure 28, the dual RSUs 100c-1 and 100c-2 are communicatively connected via inter-RSU interfaces 4-1 and 4-2. For example, the inter-RSU interface 4-1 is an interface connecting a DSRC RSU (DSRC RSU function of the dual RSU) and a C-V2X RSU (C-V2X RSU function of the dual RSU). The inter-RSU interface 4-2 is an interface connecting a C-V2X RSU (C-V2X RSU function of the dual RSU) and a DSRC RSU (DSRC RSU function of the dual RSU). The inter-RSU interfaces 4-1 and 4-2 may be physically different interfaces or logically (virtually) different interfaces as long as the connection relationship can be identified. For example, the inter-RSU interfaces 4-1 and 4-2 may be VLAN interfaces with different VLAN IDs, or may be tunnel interfaces with different tunnel IDs.

[0149] Furthermore, the storage unit 104 included in the DSRC RSU function in the DUAL RSU 100c stores a neighbor relationship table including information about the connected DUAL RSU 100c (such as an IP address and VLAN-ID for connecting with the C-V2X RSU function) as neighbor RSU information. The storage unit 114 included in the C-V2X RSU function in the DUAL RSU 100c stores a neighbor relationship table including information about the connected DUAL RSU 100c (such as an IP address and VLAN-ID for connecting with the DUAL RSU function) as neighbor RSU information.

[0150] 29 and 30 show examples of operation of the wireless communication system 3 according to some embodiments. Fig. 29 shows an example in which a BSM from a DSRC OBU 200a is transferred between dual RSUs 100c. Fig. 30 shows an example in which a BSM from a C-V2X OBU 200b is transferred between dual RSUs 100c.

[0151] In the example of Fig. 29, the operations other than the transfer between the dual RSUs 100c are the same as those of Fig. 26. That is, the DSRC OBU 200a-1 transmits a BSM in the DSRC format (S401).

[0152] Next, the dual RSU 100c-1 transmits the BSM from the DSRC OBU 200a-1 in PC5 format (S402) and transfers it to the dual RSU 100c-2 (S403). Steps S402 and S403 may be executed in parallel, or one of them may be executed first.

[0153] For example, the DUAL RSU 100c-1 (DSRC communication unit 101) receives a BSM from the DSRC OBU 200a-1 using the DSRC method, and the DUAL RSU 100c-1 (C-V2X communication unit 111) broadcasts the received BSM to the surrounding area using the C-V2X PC5 method. This allows the C-V2X OBU 200b-1 to receive the BSM from the DUAL RSU 100c-1 using the C-V2X PC5 method and determine the location of the DSRC OBU 200a-1.

[0154] Furthermore, the DUAL RSU 100c-1 (C-V2X inter-RSU communication unit 102) transmits the BSM received from the DSRC OBU 200a-1 to the DUAL RSU 100c-2 via the inter-RSU interface 4-1. For example, the DUAL RSU 100c-1 obtains the IP address and VLAN-ID of the DUAL RSU 100c-2 (C-V2X RSU function) from the neighbor relationship table in the storage unit 104, and transmits an IP packet including the BSM to the obtained IP address and VLAN-ID.

[0155] Next, the DUAL RSU 100c-2 transmits the BSM from the DUAL RSU 100c-1 in the C-V2X PC5 format (S404). For example, the DUAL RSU 100c-2 (DSRC inter-RSU communication unit 112) receives an IP packet containing a BSM transmitted from the DUAL RSU 100c-1 to the DUAL RSU 100c-2 (C-V2X RSU function) via the inter-RSU interface 4-1. The DUAL RSU 100c-2 (C-V2X communication unit 111) broadcasts the BSM contained in the received IP packet to its surroundings as a C-V2X PC5 format message. As a result, the C-V2X OBU 200b-2 can receive a BSM from the DUAL RSU 100c-2 in the C-V2X PC5 format and ascertain the position of the DSRC OBU 200a-1, etc.

[0156] The dual RSU 100c-2 may further transmit the BSM received from the dual OBU 200c-1 using the DSRC method. For example, if the DSRC OBU 200a-2 is located outside the wireless communication range of the DSRC OBU 200a-1 but within the wireless communication range of the dual RSU 100c-2, the DSRC OBU 200a-2 can receive the BSM from the dual RSU 100c-2 using the DSRC method and determine the location of the DSRC OBU 200a-1.

[0157] In the example of Fig. 30, the operations other than the transfer between the dual RSUs 100c are the same as those of Fig. 27. That is, the C-V2X OBU 200b-1 transmits a BSM in the C-V2X PC5 method (S411).

[0158] Next, the DUAL RSU 100c-1 transmits the BSM from the C-V2X OBU 200b-1 in the DSRC method (S412) and transfers it to the DUAL RSU 100c-2 (S413). Steps S412 and S413 may be executed in parallel, or one of them may be executed first.

[0159] For example, the DUAL RSU 100c-1 (C-V2X communication unit 111) receives a BSM from the C-V2X OBU 200b-1 using the C-V2X PC5 method, and the DUAL RSU 100c-1 (DSRC communication unit 101) broadcasts the received BSM to the surrounding area using the DSRC method. This allows the DSRC OBU 200a-1 to receive the BSM from the DUAL RSU 100c-1 using the DSRC method and determine the position of the C-V2X OBU 200b-1.

[0160] Furthermore, the DUAL RSU 100c-1 (the DSRC inter-RSU communication unit 112) transmits the BSM received from the C-V2X OBU 200b-1 to the DUAL RSU 100c-2 via the inter-RSU interface 4-2. For example, the DUAL RSU 100c-1 obtains the IP address and VLAN-ID of the DUAL RSU 100c-2 (DSRC RSU function) from the neighbor relationship table in the storage unit 114, and transmits an IP packet including the BSM to the obtained IP address and VLAN-ID.

[0161] Next, the Dual RSU 100c-2 transmits the BSM from the Dual RSU 100c-1 using the DSRC method (S414). For example, the Dual RSU 100c-2 (C-V2X inter-RSU communication unit 102) receives an IP packet containing a BSM sent from the Dual RSU 100c-1 to the Dual RSU 100c-2 (DSRC RSU function) via the inter-RSU interface 4-2. The Dual RSU 100c-2 (DSRC communication unit 101) broadcasts the BSM contained in the received IP packet to its surroundings as a DSRC message. As a result, the DSRC OBU 200a-2 can receive a BSM from the DUAL RSU 100c-2 using the DSRC method and grasp the position of the C-V2X OBU 200b-1, etc.

[0162] The DUAL RSU 100c-2 may further transmit the BSM received from the DUAL OBU 200c-1 using the C-V2X PC5 method. For example, if the C-V2X OBU 200b-2 is located outside the wireless communication range of the C-V2X OBU 200b-1 but within the wireless communication range of the DUAL RSU 100c-2, the C-V2X OBU 200b-2 can receive the BSM from the DUAL RSU 100c-2 using the C-V2X PC5 method and determine the location of the C-V2X OBU 200b-1.

[0163] As described above, in this embodiment, the BSM of the OBU is transferred between the dual RSUs. Even in this case, messages such as the BSM can be transmitted and received between the DSRC OBU and the C-V2X OBU via the dual RSU.

[0164] (Embodiment 6) Next, a description will be given of embodiment 6. In this embodiment, an example will be described in which an OBU message is transferred via a control device higher than a DSRC RSU and a C-V2X RSU.

[0165] FIG. 31 shows an example configuration of a wireless communication system 3 according to some embodiments. In the example of FIG. 31, the wireless communication system 3 includes multiple DSRC RSUs 100a (100a-1 to 100a-3 in this example), multiple C-V2X RSUs 100b (100b-1 to 100b-3 in this example), and multiple control devices 300 (300a and 300b in this example). The other configurations are the same as those of FIG. 10. Note that a control device may include the functions of both the control device 300a and the control device 300b. In other words, a single control device may transfer messages between the multiple DSRC RSUs 100a and the multiple C-V2X RSUs 100b. Note that the control devices 300a and 300b may control not only the DSRC RSUs 100a and the C-V2X RSUs 100b, but also a dual RSU.

[0166] The control device 300a is a control device (also referred to as a DSRC control device) that controls multiple DSRC RSUs 100a. The DSRC control device 300a and the DSRC RSUs 100a are communicatively connected via an arbitrary upper interface 6a such as an IP interface. For example, the DSRC RSU 100a includes an upper communication unit that communicates with the DSRC control device 300a via the upper interface 6a.

[0167] The control device 300b is a control device (also referred to as a C-V2X control device) that controls multiple C-V2X RSUs 100b. The C-V2X control device 300b and the C-V2X RSUs 100b are communicatively connected via an arbitrary upper interface 6b such as an IP interface. For example, the C-V2X RSU 100b includes an upper communication unit that communicates with the C-V2X control device 300b via the upper interface 6a.

[0168] The DSRC control device 300a and the C-V2X control device 300b are communicatively connected via an inter-control device interface 5. The inter-control device interface 5 may be any interface that allows communication between the control devices. For example, the inter-control device interface 5 may be an IP interface, similar to the inter-RSU interface 4.

[0169] Fig. 32 shows an example configuration of a DSRC control device 300a according to some embodiments. In the example of Fig. 32, the DSRC control device 300a includes an inter-DSRC RSU communication unit 301, an inter-control device communication unit 302, a transfer unit 303, and a storage unit 304. The configuration of Fig. 32 is just an example, and other configurations may be used as long as the DSRC control device 300a according to some embodiments can operate.

[0170] The DSRC control device 300a may also include other functions necessary as a control device that controls the RSU. For example, the DSRC control device 300a may include a control unit that controls the operation of the DSRC RSU 100a based on information acquired from the DSRC RSU 100a. Furthermore, multiple functions included in the DSRC control device 300a may be implemented by a single device or multiple devices. The multiple devices that make up the DSRC control device 300a may be located in the same place or in different places. The devices that make up the DSRC control device 300a may include physical devices (computers) or virtual machines operating on a virtualization platform. The same applies to the C-V2X control device 300b.

[0171] The DSRC RSU communication unit 301 communicates with multiple DSRC RSUs 100a via the upper interface 6a. For example, if the upper interface 6a is an IP interface, the DSRC RSU communication unit 301 transmits and receives IP packets containing messages such as BSMs via the upper interface 6a. For example, the DSRC RSU communication unit 301 receives IP packets containing messages such as BSMs sent from one or more DSRC RSUs 100a to the DSRC control device 300a, and transmits IP packets containing messages such as BSMs to one or more DSRC RSUs 100a.

[0172] The inter-controller communication unit 302 communicates with the control device 300b via the inter-controller interface 5. For example, if the inter-controller interface 5 is an IP interface, the inter-controller communication unit 302 transmits and receives IP packets containing messages such as BSM via the inter-controller interface 5. For example, the inter-controller communication unit 302 receives IP packets containing messages such as BSM that are sent from the control device 300b to the control device 300a (or to the DSRC RSU), and also transmits IP packets containing messages such as BSM to the control device 300b (or to the C-V2X RSY).

[0173] The transfer unit 303 controls the transfer of messages between the inter-DSRC RSU communication unit 301 and the inter-controller communication unit 302. For example, the transfer unit 303 controls the transmission of messages received from multiple DSRC RSUs 100a to the control unit 300b, and also controls the transmission of messages received from the control unit 300b to multiple DSRC RSUs 100a.

[0174] The storage unit 304 stores a neighbor relationship table that includes multiple RSUs (neighbor RSUs) in the vicinity of the DSRC RSU 100a. The neighbor relationship table in the storage unit 304 is the same as the table stored in the DSRC RSU 100a. Each neighbor relationship table stores information about the C-V2X RSU 100b in the vicinity of the DSRC RSU 100a as neighbor RSU information of the DSRC RSU 100a. For example, the forwarding unit 303 transmits, to the control device 300b, an IP packet addressed to the C-V2X RSU 100b that has a neighbor relationship with the DSRC RSU 100a, based on the neighbor relationship table for the DSRC RSU 100a in the storage unit 304.

[0175] Figure 33 shows a configuration example of a C-V2X control device 300b according to some embodiments. In the example of Figure 33, the C-V2X control device 300b includes a C-V2X inter-RSU communication unit 311, an inter-control device communication unit 312, a transfer unit 313, and a storage unit 314. The configuration of Figure 33 is just one example, and other configurations may be used as long as the operation of the C-V2X control device 300b according to some embodiments is possible.

[0176] The C-V2X inter-RSU communication unit 311 communicates with multiple C-V2X RSUs 100b via the upper interface 6b. For example, if the upper interface 6b is an IP interface, the C-V2X inter-RSU communication unit 311 transmits and receives IP packets containing messages such as BSMs via the upper interface 6b. For example, the C-V2X inter-RSU communication unit 311 receives IP packets containing messages such as BSMs sent from one or more C-V2X RSUs 100b to the C-V2X control device 300b, and also transmits IP packets containing messages such as BSMs to one or more C-V2X RSUs 100b.

[0177] The inter-control device communication unit 312 communicates with the control device 300a via the inter-control device interface 5. For example, if the inter-control device interface 5 is an IP interface, the inter-control device communication unit 312 transmits and receives IP packets containing messages such as BSMs via the inter-control device interface 5. For example, the inter-control device communication unit 312 receives IP packets containing messages such as BSMs that are sent from the control device 300a to the control device 300b (or to the C-V2X RSU), and also transmits IP packets containing messages such as BSMs to the control device 300a (or to the DSRC RSU).

[0178] The forwarding unit 313 controls the forwarding of messages between the C-V2X inter-RSU communication unit 311 and the inter-control device communication unit 312. For example, the forwarding unit 313 controls messages received from multiple C-V2X RSUs 100b to be transmitted to the control device 300a, and also controls messages received from the control device 300a to be transmitted to multiple C-V2X RSUs 100b.

[0179] The memory unit 314 stores a neighbor relationship table that includes RSUs (neighbor RSUs) in the vicinity of multiple C-V2X RSUs 100b. The neighbor relationship table in the memory unit 314 is the same as the table stored in the C-V2X RSU 100b. Each neighbor relationship table stores information about the DSRC RSUs 100a in the vicinity of the C-V2X RSU 100b as neighbor RSU information for the C-V2X RSU 100b. For example, the forwarding unit 313 transmits IP packets addressed to the DSRC RSUs 100a that have a neighbor relationship with the C-V2X RSU 100b to the control device 300a based on the neighbor relationship table for the C-V2X RSU 100b in the memory unit 314.

[0180] 34 and 35 show examples of operation of the wireless communication system 3 according to some embodiments. Fig. 34 shows an example in which a BSM from a DSRC OBU 200a is transferred between control devices 300. Fig. 35 shows an example in which a BSM from a C-V2X OBU 200b is transferred between control devices 300.

[0181] 34, the DSRC OBU 200a-1 transmits a BSM in the DSRC system (S501). Subsequently, the DSRC RSU 100a-3 transfers the BSM from the DSRC OBU 200a-1 to the DSRC control device 300a (S502). For example, the DSRC RSU 100a-3 receives the BSM from the DSRC OBU 200a-1 in the DSRC system and transmits an IP packet including the received BSM to the DSRC control device 300a via the upper interface 6a.

[0182] Next, the DSRC control device 300a transfers the BSM from the DSRC RSU 100a-3 to the control device 300b (S503). For example, the DSRC control device 300a receives an IP packet including the BSM from the DSRC RSU 100a-3 via the upper interface 6a, and transfers the received IP packet including the BSM to the C-V2X control device 300b via the inter-control device interface 5. For example, the DSRC control device 300a obtains the IP address of the C-V2X RSU 100b-1, which has a neighbor relationship with the DSRC RSU 100a-3, from the neighbor relationship table of the DSRC RSU 100a-3, and transmits an IP packet (including the BSM) addressed to the obtained IP address to the C-V2X control device 300b via the inter-control device interface 5. For example, the DSRC control device 300a may filter the BSM to be transferred, as in the third embodiment.

[0183] Next, the C-V2X control device 300b transfers the BSM from the DSRC control device 300a to the C-V2X RSU 100b-1 (S504). For example, the C-V2X control device 300b receives an IP packet (including a BSM) addressed to the C-V2X RSU 100b-1 from the DSRC control device 300a via the inter-control device interface 5, and transmits the IP packet including the received BSM to the C-V2X RSU 100b-1 via the upper interface 6b.

[0184] The C-V2X control device 300b may transmit the BSM from the DSRC control device 300a to multiple C-V2X RSUs 100b. For example, the C-V2X control device 300b may transmit the BSM to the C-V2X RSUs 100b-1 and 100b-2. For example, the DSRC control device 300a may transmit an IP packet addressed to broadcast, and the IP packet received by the C-V2X control device 300b may be broadcast to all C-V2X RSUs 100b. The DSRC control device 300a may transmit an IP packet addressed to multicast, and the IP packet received by the C-V2X control device 300b may be multicast to multiple C-V2X RSUs 100b. The DSRC control device 300a may receive IP packets addressed to the C-V2X RSU 100b-1 and IP packets addressed to the C-V2X RSU 100b-2 from the DSRC control device 300a, and transmit the IP packets to the C-V2X RSU 100b-1 and the C-V2X RSU 100b-2, respectively.

[0185] Next, the C-V2X RSU 100b-1 transmits the BSM from the C-V2X control device 300b in the C-V2X PC5 format (S505). For example, the C-V2X RSU 100b-1 receives an IP packet containing the BSM from the C-V2X control device 300b via the upper interface 6b, and broadcasts the BSM contained in the received IP packet to its surroundings as a message in the C-V2X PC5 format. This allows the C-V2X OBUs 200b-1 and 200b-2 to receive the BSM from the C-V2X RSU 100b-1 in the C-V2X PC5 format and determine the location of the DSRC OBU 200a-1, etc.

[0186] 35, the C-V2X OBU 200b-1 transmits a BSM in the C-V2X PC5 format (S511). Subsequently, the C-V2X RSU 100b-1 transfers the BSM from the C-V2X OBU 200b-1 to the C-V2X control device 300b (S512). For example, the C-V2X RSU 100b-1 receives a BSM from the C-V2X OBU 200b-1 in the C-V2X PC5 format and transmits an IP packet including the received BSM to the C-V2X control device 300b via the upper interface 6b.

[0187] Next, the C-V2X control device 300b forwards the BSM from the C-V2X RSU 100b-1 to the control device 300a (S513). For example, the C-V2X control device 300b receives an IP packet including the BSM from the C-V2X RSU 100b-1 via the upper interface 6b, and forwards the received IP packet including the BSM to the control device 300a via the inter-control device interface 5. For example, the C-V2X control device 300b obtains the IP address of the DSRC RSU 100a-3, which has a neighbor relationship with the C-V2X RSU 100b-1, from the neighbor relationship table of the C-V2X RSU 100b-1, and transmits the IP packet (including the BSM) addressed to the obtained IP address to the DSRC control device 300a via the inter-control device interface 5. For example, the C-V2X control device 300b may filter the BSM to be transferred, as in the third embodiment.

[0188] Next, the DSRC control device 300a transfers the BSM from the C-V2X control device 300b to the DSRC RSU 100a-3 (S514). For example, the DSRC control device 300a receives an IP packet (including the BSM) addressed to the DSRC RSU 100a-3 from the control device 300b via the inter-control device interface 5, and transmits the IP packet including the received BSM to the DSRC RSU 100a-3 via the upper interface 6a.

[0189] The DSRC control device 300a may transmit the BSM from the C-V2X control device 300b to multiple DSRC RSUs 100a. For example, the DSRC control device 300a may transmit the BSM to the DSRC RSUs 100a-2 and 100a-3. For example, the C-V2X control device 300b may transmit an IP packet addressed to broadcast, and the IP packet received by the DSRC control device 300a may be broadcast to all DSRC RSUs 100a. The C-V2X control device 300b may transmit an IP packet addressed to multicast, and the IP packet received by the DSRC control device 300a may be multicast to multiple DSRC RSUs 100a. The C-V2X control device 300b may receive IP packets addressed to the DSRC RSU 100a-2 and IP packets addressed to the DSRC RSU 100a-3 from the C-V2X control device 300b, and transmit the respective IP packets to the DSRC RSU 100a-2 and the DSRC RSU 100b-2.

[0190] Next, the DSRC RSU 100a-3 transmits the BSM from the DSRC control device 300a in the DSRC system (S515). For example, the DSRC RSU 100a receives an IP packet containing the BSM from the DSRC control device 300a via the upper interface 6a, and broadcasts the BSM contained in the received IP packet to its surroundings as a DSRC message. This allows the DSRC OBUs 200a-1 and 200a-2 to receive the BSM from the DSRC RSU 100a-3 in the DSRC system and to ascertain the location of the C-V2X OBU 200b-1, etc.

[0191] As described above, in this embodiment, OBU messages are transferred via a control device higher than the DSRC RSU and C-V2X RSU. Even in this case, BSMs can be transmitted and received between the DSRC OBU and C-V2X OBU via the RSU and the control device. Furthermore, the control device can centrally control transfers of multiple RSUs.

[0192] (Seventh embodiment) Next, a seventh embodiment will be described. In this embodiment, an example will be described in which neighbor relationships of RSUs are automatically registered on a distance basis.

[0193] FIG. 36 shows an example configuration of a wireless communication system 3 according to some embodiments. In the example of FIG. 36, the wireless communication system 3 includes RSUs 100-1 to 100-5 and a control device 300c. Each of the RSUs 100-1 to 100-5 may be a DSRC RSU 100a or a C-V2X RSU 100b. The control device 300c controls multiple RSUs 100, including the DSRC RSU 100a and the C-V2X RSU 100b. As in the sixth embodiment, the control device 300c and the multiple RSUs 100 are communicatively connected via any upper interface 6. For example, when a new RSU 100-1 (new station) is added, the control device 300c detects neighbor RSUs around the RSU 100-1. For example, the control device 300c determines the RSUs 100-2 and 100-3 as neighbor RSUs based on the distance from the RSU 100-1, and registers the neighbor relationship.

[0194] FIG. 37 shows a configuration example of a control device 300c according to some embodiments. In the example of FIG. 37, the control device 300c includes an acquisition unit 321, a determination unit 322, a registration unit 323, and a storage unit 324. Note that the control device 300c may have the same functions as the DSRC control device 300a and the C-V2X control device 300b according to the sixth embodiment. For example, the control device 300c may be the same device as the DSRC control device 300a and the C-V2X control device 300b.

[0195] The acquisition unit 321 acquires new station information of the RSU 100. When a new RSU 100 is added, the acquisition unit 321 acquires the new station information from the added RSU 100. The new station information includes the RSU's communication method, location information, IP address, etc., similar to the RSU information in the neighbor relationship table. If an IP address has not yet been assigned, the IP address may not be included.

[0196] The determination unit 322 determines neighbor RSUs around the newly added RSU 100. That is, the determination unit 322 determines the neighbor relationship between the new RSU 100 and other RSUs 100. The determination unit 322 determines the neighbor RSUs based on the communication method and location information included in the acquired new station information. For example, the determination unit 322 determines that other RSUs 100 using a different communication method within a predetermined distance from the new RSU 100 are neighbor RSUs that have a neighbor relationship with the new RSU 100. For example, the determination unit 322 determines that the DSRC method or C-V2X PC5 method and the dual method are different communication methods. Even if both RSUs 100 use the dual method, the determination unit 322 may determine that they are different communication methods.

[0197] The registration unit 323 registers neighbor RSUs around the newly added RSU 100. That is, the registration unit 323 registers the neighbor relationship determined by the determination unit 322. For example, the registration unit 323 registers (stores) the neighbor relationship between the new RSU 100 and the neighbor RSU in the storage unit 324. The registration unit 323 registers the neighbor relationship (neighbor RSU information) between the new RSU 100 and the neighbor RSU.

[0198] The storage unit 324 stores information about each RSU 100. The storage unit 324 stores new station information acquired from each RSU 100 and neighbor relationships between each RSU 100 and other neighbor RSUs. The storage unit 324 may store a neighbor relationship table indicating the neighbor relationships of each RSU, similar to the DSRC control device 300a and the C-V2X control device 300b.

[0199] FIG. 38 shows an example of the operation of the wireless communication system 3 according to some embodiments. In the example of FIG. 38, when a new RSU 100-1 is added to the wireless communication system 3, the RSU 100-1 transmits a new station registration message to the control device 300c (S601). The RSU 100-1 transmits a new station registration message including the communication method, location information, etc. of the RSU 100-1, and requests registration of the RSU 100-1. The control device 300c receives the new station registration message from the control device 300c, and stores the communication method, location information, etc. of the RSU 100-1 included in the new station registration message in the storage unit 324. The control device 300c may assign an IP address to the RSU 100-1 and store the assigned IP address in the storage unit 324 together with the communication method, location information, etc.

[0200] Next, the control device 300c determines the neighbor relationships between the RSU 100-1 and other RSUs (S602). The control device 300c determines neighbor RSUs around the RSU 100-1 based on the communication method and location information of the RSU 100-1 included in the new station registration message and the communication methods and location information of the other RSUs 100. For example, if the location of the RSU 100-2 is within a predetermined distance from the RSU 100-1 and the communication method of the RSU 100-2 is different from that of the RSU 100-1, the control device 300c determines the RSU 100-2 as a neighbor RSU.

[0201] Next, the control device 300c transmits a neighbor registration message to the RSUs 100-1 and 100-2 to register the neighbor relationship (S603). When the control device 300c determines that the RSU 100-2 is the neighbor RSU of the RSU 100-1, the control device 300c registers the neighbor relationship between the RSUs 100-1 and 100-2 in the storage unit 324. The control device 300c transmits a neighbor registration message indicating the neighbor relationship between the RSUs 100-1 and 100-2 to the RSUs 100-1 and 100-2. For example, the control device 300c transmits a neighbor registration message to the RSU 100-2 that includes the communication method, location information, IP address, etc. of the RSU 100-1 as neighbor RSU information. The RSU 100-2 registers the information included in the received neighbor registration message in the neighbor relationship table (storage unit 104 or 114). For example, the control device 300c transmits a neighbor registration message to the RSU 100-1, the neighbor registration message including the communication method, location information, IP address, etc. of the RSU 100-2 as neighbor RSU information. The RSU 100-1 registers the information included in the received neighbor registration message in the neighbor relationship table (storage unit 104 or 114).

[0202] Thereafter, the RSUs 100-1 and 100-2 forward the BSM from the OBU 200 based on the neighbor RSU information registered in the neighbor relationship table, as in the second embodiment. For example, when the RSU 100-2 receives a BSM from the OBU 200-1 (S604), it forwards the received BSM to the RSU 100-1 in accordance with the neighbor relationship table (S605). The RSU 100-1 receives the BSM from the RSU 100-2 and transmits the received BSM to the OBU 200-2 (S606).

[0203] As described above, in this embodiment, the control device determines the neighbor relationships of RSUs based on distance and registers the neighbor relationships in the RSUs. This allows the RSUs' neighbor relationship tables to be automatically registered and message transfer between RSUs to begin.

[0204] (Embodiment 8) Next, embodiment 8 will be described. In this embodiment, an example will be described in which neighbor relationships of RSUs are automatically registered based on measurements of OBUs. This embodiment is an example in which a dual OBU and a single RSU are used.

[0205] 39 illustrates a configuration example of a dual OBU 200c according to some embodiments. In the example of FIG. 39, the dual OBU 200c includes a DSRC communication unit 201, a vehicle information acquisition unit 202, a message processing unit 203, and a C-V2X communication unit 211, similar to the DSRC OBU 200a and the C-V2X OBU according to the second embodiment. The dual OBU 200c further includes an acquisition unit 221, a holding unit 222, and a notification unit 223.

[0206] The acquisition unit 221 acquires RSU information from the RSU 100. For example, the acquisition unit 221 may receive a broadcast signal broadcast from a RSU 100 within its coverage area and acquire, as RSU information, the ID (such as an IP address), location information, communication method, and the like of the RSU 100 included in the broadcast signal. The acquisition unit 221 may also measure the quality of signals (radio waves) such as the broadcast signal received from the RSU 100. For example, the acquisition unit 221 may measure the received signal strength indicator (RSSI) of the radio waves from the RSU 100 and acquire it as RSU information. For example, the acquisition unit 221 may measure the reference signal received power (RSRP) from the RSU 100 and acquire it as RSU information. For example, the acquisition unit 221 may measure the reference signal received quality (RSRQ) from the RSU 100 and acquire it as RSU information.

[0207] The holding unit 222 holds the RSU information acquired by the acquisition unit 221 from the RSU 100. For example, the RSU information may include an ID, an RSSI, location information, a communication method, etc. The holding unit 222 may hold the most recently acquired RSU information, or may hold a history of RSU information acquired in the past.

[0208] When the RSU 100 in its coverage area is switched (when the RSU 100 moves to the communication area of ​​a different RSU 100), the notification unit 223 notifies the new RSU 100 of the immediately previous RSU information stored in the storage unit 222. The notification unit 223 may notify all of the ID, RSSI, location information, communication method, etc. as the RSU information, or may notify only the ID and location information.

[0209] 40 shows an example configuration of an RSU 100 according to some embodiments. The RSU 100 is a single RSU and may be a DSRC RSU 100a or a C-V2X OBU 200b. In the example of FIG. 40, the RSU 100 includes an acquisition unit 121, a determination unit 122, and a registration unit 123 in addition to the functions of the DSRC RSU 100a or the C-V2X OBU 200b.

[0210] The acquisition unit 121 acquires RSU information from the dual OBU 200c. The acquisition unit 121 acquires RSU information from the dual OBU 200c, including the ID, RSSI, location information, communication method, etc. of the RSU 100 within the range of the dual OBU 200c most recently.

[0211] Based on the RSU information of the RSU 100 most recently acquired from the DUAL OBU 200c, the determination unit 122 determines whether to register the RSU 100 (considered a neighbor candidate) in the RSU information as a neighbor RSU. That is, the determination unit 122 determines the neighbor relationship between the RSU 100 itself and the neighbor candidate RSU 100. For example, if the neighbor candidate RSU 100 is within a predetermined distance from the RSU 100 and uses a different communication method than the RSU 100 itself, the determination unit 122 determines that a neighbor relationship should be registered (that a neighbor relationship exists). Furthermore, the determination unit 122 may determine that a neighbor relationship should be registered if the RSSI of the RSU 100 is equal to or greater than a predetermined value. For example, even if the RSU 100 is located nearby, the RSU 100 may experience poor radio wave conditions. Therefore, by taking the RSSI into consideration, the determination of whether to register a neighbor relationship can be made appropriately based on the actual radio wave conditions, not just the RSU's location.

[0212] The registration unit 123 registers the neighbor relationship between the RSU 100 itself and the neighbor RSU. For example, when the registration unit 123 determines to register the neighbor candidate RSU 100, it registers the received RSU information of the immediately previous RSU 100 as neighbor RSU information in the stored neighbor relationship table (storage unit 104 or 114). The registration unit 123 may request the control device to register the neighbor relationship, or may request the neighbor candidate RSU 100 to register the neighbor relationship.

[0213] 41 illustrates an example of operation of the wireless communication system 3 according to some embodiments. Figure 41 illustrates a neighbor relationship registration process when the DUAL OBU 200c moves from within the range of the DSRC RSU 100a to within the range of the C-V2X RSU 100b.

[0214] 41 , the DUAL OBU 200c, within the range of the DSRC RSU 100a, acquires the RSU information of the DSRC RSU 100a (S701). For example, the DSRC RSU 100a periodically transmits a broadcast signal using the DSRC method, the broadcast signal including the RSU information of the DSRC RSU 100a. The broadcast signal includes the ID (such as an IP address), location information, communication method (DSRC), etc. of the DSRC RSU 100a. The DUAL OBU 200c receives the broadcast signal from the DSRC RSU 100a using the DSRC method, and acquires the ID, location information, communication method, etc. of the DSRC RSU 100a included in the broadcast signal. Furthermore, the dual OBU 200c may measure and acquire the RSSI from radio waves of a notification signal, etc. The dual OBU 200c holds the acquired ID, location information, communication method (DSRC), RSSI, etc. as RSU information of the DSRC RSU 100a.

[0215] Next, the DUAL OBU 200c moves into the range of the C-V2X RSU 100b (S702). For example, the C-V2X RSU 100b periodically transmits a broadcast signal including RSU information of the C-V2X RSU 100b in the C-V2X PC5 system. The DUAL OBU 200c receives the broadcast signal from the C-V2X RSU 100b in the C-V2X PC5 system, and if the ID, location information, and communication system of the received broadcast signal differ from those of the immediately preceding RSU, the DUAL OBU 200c detects that it has moved into the range of a different RSU (the C-V2X RSU 100b).

[0216] Next, the DUAL OBU 200c transmits a neighbor information message to the C-V2X RSU 100b (S703). For example, when the DUAL OBU 200c detects that it has moved into the range of the C-V2X RSU 100b, the DUAL OBU 200c notifies the C-V2X RSU 100b of the RSU information of the DSRC RSU 100a that it held (was in range) immediately before, using the C-V2X PC5 method. The neighbor information message includes the ID, location information, RSSI, communication method (DSRC), etc., of the held DSRC RSU 100a.

[0217] Next, the C-V2X RSU 100b determines whether to add / update a neighbor relationship based on the neighbor information message (S704). The C-V2X RSU 100b receives the neighbor information message using the C-V2X PC5 method and determines the neighbor relationship of the DSRC RSU 100a (neighbor candidate) based on the ID, location information, RSSI, and communication method (DSRC) of the DSRC RSU 100a included in the received neighbor information message. For example, if the location of the DSRC RSU 100a is within a predetermined distance from the C-V2X RSU 100b and the communication method of the DSRC RSU 100a is different from that of the C-V2X RSU 100b, the C-V2X RSU 100b determines to add / update the neighbor relationship of the C-V2X RSU 100b by the DSRC RSU 100a. That is, the C-V2X RSU 100b determines to register the DSRC RSU 100a as a neighbor RSU in the neighbor relationship table of the C-V2X RSU 100b. Furthermore, the C-V2X RSU 100b may determine to register the neighbor relationship if the RSSI is equal to or greater than a predetermined value.

[0218] Furthermore, if the C-V2X RSU 100b determines to add / update a neighbor relationship, it requests the control device 300c to register (add / update) the neighbor relationship (S705). For example, the C-V2X RSU 100b transmits a registration request message including RSU information such as the ID, location information, RSSI, and communication method (DSRC) of the DSRC RSU 100a. In response to the request from the C-V2X RSU 100b, the control device 300c determines whether to register the neighbor relationship (S706) and transmits the determination result to the C-V2X RSU 100b (S707). The determination by the control device 300c may be the same as in the seventh embodiment. Note that steps S705 to S707 may be omitted.

[0219] Next, the C-V2X RSU 100b requests neighbor registration from the DSRC RSU 100a (S708). For example, the C-V2X RSU 100b transmits a neighbor registration request message including RSU information such as its ID, location information, and communication method (C-V2X PC5) to the DSRC RSU 100a. The DSRC RSU 100a registers the RSU information from the C-V2X RSU 100b in a neighbor relationship table and transmits a registration result (registration OK) to the C-V2X RSU 100b (S709). The DSRC RSU 100a may determine whether to register the neighbor relationship with the C-V2X RSU 100b. In addition, the C-V2X RSU 100b registers the RSU information of the DSRC RSU 100a in the neighbor relationship table, which starts the transfer of BSM between the DSRC RSU 100a and the C-V2X RSU 100b (S710).

[0220] As described above, in this embodiment, the DUAL OBU notifies the RSU of the information of the immediately preceding RSU, and registers the neighbor relationship in the RSU based on the notified information. Even in this case, the RSU's neighbor relationship table is automatically registered, and message transfer between the RSUs can be started.

[0221] (Ninth Embodiment) Next, a ninth embodiment will be described. In this embodiment, another example of automatically registering neighbor RSUs based on OBU measurements will be described. This embodiment is an example in which a dual RSU and a single OBU are used. The dual RSU 100c is the same as that shown in FIG. 40. That is, the dual RSU 100c includes the functions of the dual RSU 100c shown in FIG. 25, as well as the acquisition unit 121, determination unit 122, and registration unit 123 shown in FIG. 40.

[0222] Fig. 42 shows an example of the configuration of a DSRC OBU 200a according to some embodiments. In the example of Fig. 42, the DSRC OBU 200a includes a DSRC communication unit 201, a vehicle information acquisition unit 202, and a message processing unit 203, similar to the DSRC OBU 200a shown in Fig. 13, and further includes an acquisition unit 221, a holding unit 222, and a notification unit 223, similar to Fig. 39.

[0223] Figure 43 shows a configuration example of a C-V2X OBU 200b according to some embodiments. In the example of Figure 43, the C-V2X OBU 200b includes a C-V2X communication unit 211, a vehicle information acquisition unit 202, and a message processing unit 203, similar to the C-V2X OBU 200b shown in Figure 15, and further includes an acquisition unit 221, a storage unit 222, and a notification unit 223, similar to Figure 39.

[0224] 44 illustrates an example of operation of the wireless communication system 3 according to some embodiments. This figure illustrates a neighbor relationship registration process when the DSRC OBU 200a (single OBU) moves from the range of the dual RSU 100c-1 to the range of the dual RSU 100c-2. The same process is performed when the C-V2X OBU 200b is used instead of the DSRC OBU 200a.

[0225] In the example of FIG. 44, the DSRC OBU 200a, within the range of the DUAL RSU 100c-1, acquires information about the DUAL RSU 100c-1 (S711). For example, the DUAL RSU 100c-1 periodically transmits a broadcast signal including RSU information about the DUAL RSU 100c-1 using the DSRC method and the C-V2X PC5 method. The broadcast signal includes the ID (IP address, etc.) of the DUAL RSU 100c-1, location information, communication method (DUAL), etc. The DSRC OBU 200a receives a broadcast signal from the DUAL RSU 100c-1 using the DSRC method and acquires the ID, location information, communication method, etc. of the DUAL RSU 100c-1 included in the broadcast message. The DSRC OBU 200a may also acquire the RSSI by measuring it from radio waves of a notification signal, etc. The DSRC OBU 200a holds the acquired ID, location information, communication method (DUAL), RSSI, etc. as RSU information of the DUAL RSU 100c-1.

[0226] Next, the DSRC OBU 200a moves into the range of the DUAL RSU 100c-2 (S712). For example, the DUAL RSU 100c-2 periodically transmits a notification signal including RSU information of the DUAL RSU 100c-2 using the DSRC method and the C-V2X PC5 method. The DSRC OBU 200a receives the notification signal from the DUAL RSU 100c-2 using the DSRC method, and if the ID and location information of the received notification signal are different from those of the immediately preceding RSU, the DSRC OBU 200a detects that it has moved into the range of a different RSU (the DUAL RSU 100c-2).

[0227] Next, the DSRC OBU 200a transmits a neighbor information message to the DUAL RSU 100c-2 (S713). For example, when the DSRC OBU 200a detects that it has moved into the range of the DUAL RSU 100c-2, the DSRC OBU 200a notifies the DUAL RSU 100c-2 of the RSU information of the DUAL RSU 100c-1 that it held (was in range) just before, using the DSRC method. The neighbor information message includes the ID, location information, RSSI, communication method (DUAL), etc., of the held DUAL RSU 100c-1.

[0228] Next, the DUAL RSU 100c-2 determines whether to add / update a neighbor relationship based on the neighbor information message (S714). The DUAL RSU 100c-2 determines the neighbor relationship in the same manner as in FIG. 41. For example, if the DUAL RSU 100c-2 receives a neighbor information message using the DSRC method and the location of the DUAL RSU 100c-1 (neighbor candidate) included in the neighbor information message is within a predetermined distance from the DUAL RSU 100c-2, the DUAL RSU 100c-2 determines to add / update the neighbor relationship with the DUAL RSU 100c-1. In other words, the DUAL RSU 100c-2 determines to register the DUAL RSU 100c-1 as a neighbor RSU in its neighbor relationship table. Furthermore, if the RSSI is equal to or greater than a predetermined value, it may be determined that the neighbor relationship is to be registered.

[0229] Also, similar to FIG. 41, when the DUAL RSU 100c-2 determines that a neighbor relationship should be added / updated, it requests the control device 300c to register (add / update) the neighbor relationship (S715), and the control device 300c determines whether to register the neighbor relationship (S716) and may transmit the determination result to the DUAL RSU 100c-2 (S717).

[0230] 41, the Dual RSU 100c-2 requests the Dual RSU 100c-1 to register as a neighbor (S718). For example, the Dual RSU 100c-2 sends a neighbor registration request message to the Dual RSU 100c-1, including RSU information such as the Dual RSU 100c-2's ID, location information, and communication method (DUAL). The Dual RSU 100c-1 registers the RSU information from the Dual RSU 100c-2 in the neighbor relationship table and transmits a registration result (registration OK) to the Dual RSU 100c-2 (S719). The Dual RSU 100c-1 may determine whether to register the neighbor relationship with the Dual RSU 100c-2. The dual RSU 100c-2 also registers the RSU information of the dual RSU 100c-1 in the neighbor relationship table, which starts the transfer of BSMs between the dual RSU 100c-1 and the dual RSU 100c-2 (S720).

[0231] As described above, in this embodiment, the OBU notifies the information of the immediately preceding dual RSU, and registers the neighbor relationship with the dual RSU based on the notified information. Even in this case, the neighbor relationship table of the RSU is automatically registered, and message transfer between the RSUs can be started.

[0232] The present disclosure is not limited to the above-described embodiments and may be modified as appropriate without departing from the spirit of the present disclosure. Each configuration in the above-described embodiments may be configured with hardware, software, or both, and may be configured with a single piece of hardware or software, or may be configured with multiple pieces of hardware or software. For example, each element (function) such as a control device, RSU, OBU, etc. may be implemented by a computer having a processor such as a CPU (Central Processing Unit) and a memory serving as a storage device. For example, each element may be implemented by storing a program for performing processing (methods) in the control device, RSU, OBU, etc. in the memory, and executing the program stored in the memory on the processor. Each element may be implemented, for example, as a network element on dedicated hardware, as a software instance running on the dedicated hardware, or as a virtualization function instantiated on an application platform.

[0233] 45 shows an example of the hardware configuration of the control device 300 according to some embodiments. In the example of FIG. 45, the control device 300 includes a network interface 331, a processor 332, and a memory 333.

[0234] The network interface 331 is used to communicate with other network devices (e.g., RSUs, other control devices, etc.) that make up the communication system. The network interface 331 may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series. IEEE stands for Institute of Electrical and Electronics Engineers. The network interface 331 may include an interface for communication between the control device and RSUs, and an interface for communication between the control devices.

[0235] The processor 332 may be, for example, a microprocessor, a microprocessing unit (MPU), or a CPU. The processor 332 may include multiple processors.

[0236] The memory 333 is configured by a combination of volatile memory and nonvolatile memory. The memory 333 may include multiple physically independent memory devices. The volatile memory is, for example, static random access memory (SRAM), dynamic RAM (DRAM), or a combination thereof. The nonvolatile memory is, for example, mask read only memory (MROM), electrically erasable programmable ROM (EEPROM), flash memory, a hard disk drive, or a solid-state drive (SSD), or any combination thereof. The memory 333 may include storage located remotely from the processor 332. In this case, the processor 332 may access the memory 333 via an I / O (Input / Output) interface (not shown).

[0237] The memory 333 may store software modules (computer programs) including instructions and data for performing the processes of the control device 300 described in the above-mentioned embodiments. In some implementations, the processor 332 may be configured to read and execute the software modules from the memory 333, thereby performing the processes of the control device 300 described in the above-mentioned embodiments.

[0238] 46 shows an example of the hardware configuration of the RSU 100 according to some embodiments. In the example of FIG. 46, the RSU 100 includes an RF transceiver 134, a network interface 131, a processor 132, and a memory 133.

[0239] The RF transceiver 134 performs analog RF signal processing for communication with the OBU 200. The RF transceiver 134 may include multiple transceivers (for the DSRC system, the C-V2X PC5 system, etc.). The RF transceiver 134 is coupled to the antenna 134a and the processor 132. The RF transceiver 134 receives a baseband transmit signal from the processor 132, generates a transmit RF signal, and provides the transmit RF signal to the antenna 134a. The RF transceiver 134 also generates a baseband receive signal based on the receive RF signal received by the antenna 134a and provides the baseband receive signal to the processor 132.

[0240] The network interface 131 is used to communicate with other network devices (e.g., a control device, another RSU, etc.). The network interface 131 may include, for example, a network interface card (NIC) conforming to the IEEE 802.3 series. The network interface 131 may include an interface for communication between the control device and RSUs, and an interface for communication between RSUs.

[0241] The processor 132 performs lower layer signal processing, including digital baseband signal processing for wireless communication, and upper layer signal processing, including application processing. For example, the lower layer signal processing may include signal processing of the WAVE MAC layer and Lower MAC+PHY layer for the DSRC system. The lower layer signal processing may include signal processing of the V2X protocol layer, MAC layer, and PHY layer for the C-V2X PC5 system. Furthermore, the upper layer signal processing may include processing of the WAVE Security Service layer, P2P Certificate Distribution Service layer, CRL Verification Service layer, and other application layers.

[0242] The processor 132 may include multiple processors. For example, the processor 132 may include a modem processor (e.g., a Digital Signal Processor (DSP)) that performs open-layer signal processing and an application processor (e.g., a CPU or MPU) that performs upper-layer processing. The application processor may include multiple processors (multiple processor cores). The application processor may implement various functions of the RSU 100 by executing a system software program (operating system (OS)) and various application programs read from the memory 133 or a memory not shown.

[0243] The memory 133 is configured by a combination of volatile memory and non-volatile memory. The memory 133 may include multiple physically independent memory devices. The memory 133 may also include storage located remotely from the processor 132. In this case, the processor 132 may access the memory 133 via the network interface 131 or an I / O interface (not shown).

[0244] The memory 133 may store software modules (computer programs) including instructions and data for performing the processes of the RSU 100 described in the above-described embodiments. In some implementations, the processor 132 may be configured to read and execute the software modules from the memory 133 to perform the processes of the RSU 100 described in the above-described embodiments.

[0245] 47 shows an example of the hardware configuration of the OBU 200 according to some embodiments. In the example of FIG. 47, the OBU 200 includes an RF transceiver 231, a processor 232, and a memory 233.

[0246] The RF transceiver 231 performs analog RF signal processing for communication with the RSU 100 or other OBUs. The RF transceiver 134 may include multiple transceivers (for the DSRC system, the C-V2X PC5 system, etc.). The RF transceiver 231 is coupled to the antenna 231a and the processor 232. The RF transceiver 231 receives a baseband transmit signal from the processor 232, generates a transmit RF signal, and provides the transmit RF signal to the antenna 231a. The RF transceiver 231 also generates a baseband receive signal based on the receive RF signal received by the antenna 231a and provides the baseband receive signal to the processor 232.

[0247] The processor 232 performs lower layer signal processing, including digital baseband signal processing for wireless communication, and upper layer signal processing, including application processing. For example, the lower layer signal processing may include signal processing of the WAVE MAC layer and Lower MAC+PHY layer for the DSRC system. The lower layer signal processing may include signal processing of the V2X protocol layer, MAC layer, and PHY layer for the C-V2X PC5 system. Furthermore, the upper layer signal processing may include processing of the WAVE Security Service layer, P2P Certificate Distribution Service layer, CRL Verification Service layer, and other application layers.

[0248] The processor 232 may include multiple processors. For example, the processor 232 may include a modem processor (e.g., DSP) that performs open-layer signal processing and an application processor (e.g., CPU or MPU) that performs upper-layer processing. The application processor may include multiple processors (multiple processor cores). The application processor may implement various functions of the OBU 200 by executing a system software program (operating system (OS)) and various application programs read from the memory 233 or a memory not shown.

[0249] The memory 233 is a volatile memory, a non-volatile memory, or a combination thereof. The memory 233 may include a plurality of physically independent memory devices. For example, the memory 233 may include an external memory device accessible from the processor 232. The memory 233 may also include an internal memory device integrated within the processor 232.

[0250] The memory 233 may store software modules (computer programs) including instructions and data for performing the processes described in the above-mentioned embodiments by the OBU 200. In some implementations, the processor 232 may be configured to read and execute the software modules from the memory 233, thereby performing the processes of the OBU 200 described in the above-mentioned embodiments.

[0251] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0252] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0253] Each drawing is merely an example for describing one or more embodiments. Each drawing may not relate to only one particular embodiment, but may also relate to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0254] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes.

[0255] (Supplementary Note 1) A roadside device comprising: means for receiving a message from a first on-board device using a first communication method for device-to-device direct communication; and means for forwarding the received message to another roadside device that can communicate with a second on-board device using a second communication method for device-to-device direct communication. (Supplementary Note 2) The roadside device according to Supplementary Note 1, wherein the message is a message that notifies information about a vehicle equipped with the first on-board device. (Supplementary Note 3) The roadside device according to Supplementary Note 2, wherein the message includes a Basic Safety Message (BSM). (Supplementary Note 4) The roadside device according to any one of Supplements 1 to 3, wherein one of the first communication method and the second communication method is DSRC and the other is C-V2X PC5. (Supplementary Note 5) The roadside device according to any one of Supplements 1 to 3, wherein the forwarding means forwards the message in accordance with a predetermined forwarding policy. (Supplementary Note 6) The roadside device according to Supplementary Note 5, wherein the forwarding policy includes a policy for determining whether to forward the message based on a distance between the first on-board device and the other roadside device. (Supplementary Note 7) The roadside device according to Supplementary Note 6, wherein the forwarding policy forwards the message if the distance is shorter than a predetermined value. (Supplementary Note 8) The roadside device according to Supplementary Note 5, wherein the forwarding policy includes a policy for determining whether to forward the message based on a priority of the message. (Supplementary Note 9) The roadside device according to Supplementary Note 8, wherein the forwarding policy forwards the message if the priority of the message is higher than a predetermined value. (Supplementary Note 10) The roadside device according to Supplementary Note 8, wherein the priority is based on a type of vehicle equipped with the first on-board device that transmitted the message. (Supplementary Note 11) The roadside device according to Supplementary Note 8, wherein the priority is based on a type of the message. (Supplementary Note 12) The roadside device according to Supplementary Note 5, wherein the forwarding policy includes a policy for controlling a frequency of forwarding the message. (Supplementary Note 13) The roadside device according to Supplementary Note 12, wherein the forwarding policy generates a message to be forwarded based on information included in a plurality of messages received from the first vehicle-mounted device during a predetermined period.(Supplementary Note 14) The roadside device according to Supplementary Note 13, wherein the forwarding policy generates the message to be forwarded by averaging information included in the plurality of messages. (Supplementary Note 15) The roadside device according to Supplementary Note 12, wherein the forwarding policy forwards a selected message from a plurality of messages received from the first on-board device within a predetermined period. (Supplementary Note 16) The roadside device according to Supplementary Note 5, wherein the forwarding policy includes a policy for forwarding the message related to the other roadside device based on a moving direction of a vehicle equipped with the first on-board device. (Supplementary Note 17) The roadside device according to any one of Supplements 1 to 3, further comprising means capable of communicating using the second communication method. (Supplementary Note 18) The roadside device according to any one of Supplements 1 to 3, wherein the forwarding means forwards the received message to the other roadside device capable of communicating using the first communication method and the second communication method. (Supplementary Note 19) The roadside device according to any one of Supplements 1 to 3, wherein the forwarding means forwards the message via a control device. (Supplementary Note 20) The roadside device according to any one of Supplements 1 to 3, wherein the forwarding means forwards the message via a control device that controls the roadside device and a control device that controls the other roadside devices. (Supplementary Note 21) The roadside device according to any one of Supplements 1 to 3, comprising: means for storing forwarding information indicating a forwarding relationship with the other roadside device, and the forwarding means forwards the message to the other roadside device based on the forwarding information. (Supplementary Note 22) The roadside device according to Supplementary Note 21, comprising: means for transmitting information about the roadside device to a control device; and means for acquiring information about the other roadside device from the control device and registering the acquired information in the forwarding information. (Supplementary Note 23) The roadside device according to Supplementary Note 21, comprising means for determining a forwarding relationship with the other roadside device based on information about the other roadside device, and registering in the forwarding information based on the determination result. (Supplementary Note 24) The roadside device according to Supplementary Note 23, wherein the receiving means receives information about the other roadside devices from the first vehicle-mounted device.(Supplementary Note 25) The roadside device according to Supplementary Note 24, wherein the receiving means receives information about the other roadside device from the first on-board device capable of communicating using the first communication method and the second communication method. (Supplementary Note 26) A roadside device comprising: means for receiving, from the other roadside device, a message that the other roadside device has received from the first on-board device using a first communication method for device-to-device direct communication and forwarded, and means for transmitting the received message to a second on-board device using a second communication method for device-to-device direct communication. (Supplementary Note 27) A control device comprising: means for receiving, from the first roadside device, a message that the first roadside device has received from the first on-board device using the first communication method for device-to-device direct communication, and means for forwarding the received message to another control device connected to a second roadside device that is capable of communicating with the second on-board device using the second communication method for device-to-device direct communication. (Supplementary Note 28) A control device comprising: means for receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first vehicle-mounted device using a first communication method for device-to-device direct communication; and means for transmitting, to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for device-to-device direct communication. (Supplementary Note 29) An in-vehicle device comprising: means for acquiring information about the first roadside device from the first roadside device using the first communication method for device-to-device direct communication; and means for notifying a second roadside device of the acquired information about the first roadside device using the first communication method or the second communication method. (Supplementary Note 30) A system comprising a first roadside device and a second roadside device, wherein the first roadside device comprises: means for receiving a message from a first vehicle-mounted device using a first communication method for device-to-device direct communication; and means for forwarding the received message to the second roadside device that can communicate with the second vehicle-mounted device using a second communication method for device-to-device direct communication; and the second roadside device comprises: means for receiving from the first roadside device a message that the first roadside device has received from the first vehicle-mounted device using the first communication method and forwarded; and means for transmitting the received message to the second vehicle-mounted device using the second communication method.(Supplementary Note 31) A method for a roadside device, comprising: receiving a message from a first in-vehicle device using a first communication method for device-to-device direct communication; and forwarding the received message to another roadside device that can communicate with the second in-vehicle device using a second communication method for device-to-device direct communication. (Supplementary Note 32) A method for a roadside device, comprising: receiving, from the other roadside device, a message that the other roadside device has received from the first in-vehicle device using the first communication method for device-to-device direct communication and forwarded, and transmitting the received message to a second in-vehicle device using the second communication method for device-to-device direct communication. (Supplementary Note 33) A method for a control device, comprising: receiving, from a first roadside device, a message that a first roadside device has received from a first on-board device using a first communication method for device-to-device direct communication, and transferring the received message to another control device connected to a second roadside device that can communicate with the second on-board device using a second communication method for device-to-device direct communication. (Supplementary Note 34) A method for a control device, comprising: receiving, from another control device connected to the first roadside device, a message that a first roadside device has received from the first on-board device using the first communication method for device-to-device direct communication, and transmitting the received message to a second roadside device that can communicate with the second on-board device using the second communication method for device-to-device direct communication. (Supplementary Note 35) A method for an in-vehicle device, comprising: acquiring information about a first roadside device from a first roadside device using a first communication method for device-to-device direct communication; and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or a second communication method. (Supplementary Note 36) A program for causing a computer to execute a method for a roadside device, comprising: receiving a message from a first in-vehicle device using a first communication method for device-to-device direct communication; and forwarding the received message to another roadside device that can communicate with the second in-vehicle device using a second communication method for device-to-device direct communication.(Supplementary Note 37) A program for causing a computer to execute a method for a roadside device, the method including: receiving, from another roadside device, a message that another roadside device has received from a first on-board device using a first communication method for device-to-device direct communication and forwarded, and transmitting the received message to a second on-board device using a second communication method for device-to-device direct communication. (Supplementary Note 38) A program for causing a computer to execute a method for a control device, the method including: receiving, from the first roadside device, a message that a first roadside device has received from a first on-board device using the first communication method for device-to-device direct communication, and forwarding the received message to another control device connected to a second roadside device that can communicate with the second on-board device using the second communication method for device-to-device direct communication. (Supplementary Note 39) A program for causing a computer to execute a method for a control device, the method including: receiving, from another control device connected to the first roadside device, a message that a first roadside device has received from a first in-vehicle device using a first communication method for device-to-device direct communication, and transmitting the received message to a second roadside device that can communicate with the second in-vehicle device using a second communication method for device-to-device direct communication. (Supplementary Note 40) A program for causing a computer to execute a method for an in-vehicle device, the method including: acquiring information about the first roadside device from a first roadside device using the first communication method for device-to-device direct communication, and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or the second communication method.

[0256] Some or all of the elements (e.g., configurations and functions) described in Supplementary Notes 2 to 25 that are dependent on Supplementary Note 1 (roadside device) may also be dependent on Supplementary Note 26 (roadside device), Supplementary Note 27 (controller), Supplementary Note 28 (controller), Supplementary Note 29 (on-vehicle device), Supplementary Note 30 (system), Supplements 31-35 (method), and Supplements 36-40 (program) in the same dependent relationship as Supplementary Note 2 to Supplementary Note 25. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods.

[0257] This application claims priority based on Japanese Patent Application No. 2024-090375, filed on June 4, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0258] REFERENCE SIGNS LIST 1 System 2, 3 Wireless communication system 4 Inter-RSU interface 5 Inter-controller interface 6, 6a, 6b Upper interface 10 RSU 10a First RSU 10b Second RSU 11 Receiving unit 12 Transfer unit 13 Receiving unit 14 Transmitting unit 20 OBU 20a First OBU 20b Second OBU 21 Transmitting unit 22 Receiving unit 23 Receiving unit 24 Transmitting unit 30 Control unit 30a First control unit 30b Second control unit 31 Receiving unit 32 Transferring unit 33 Receiving unit 34 Transmitting unit 100 RSU 100a DSRC RSU 100b C-V2X RSU 101 DSRC communication unit 102 C-V2X Inter-RSU communication unit 103 Transfer unit 104 Memory unit 111 C-V2X communication unit 112 DSRC inter-RSU communication unit 113 Transfer unit 114 Memory unit 121 Acquisition unit 122 Determination unit 123 Registration unit 131 Network interface 132 Processor 133 Memory 134 RF transceiver 134a Antenna 200 OBU 200a DSRC OBU 200b C-V2X OBU 201 DSRC communication unit 202 Vehicle information acquisition unit 203 Message processing unit 211 C-V2X communication unit 221 Acquisition unit 222 Holding unit 223 Notification unit 231 RF transceiver 231a Antenna 232 Processor 233 Memory 300, 300c Control device 300a DSRC control device 300b C-V2X control device 301 DSRC RSU communication unit 302 Control device communication unit 303 Transfer unit 304 Storage unit 311 C-V2X RSU communication unit 312 Control device communication unit 313 Transfer unit 314 Storage unit 321 Acquisition unit 322 Decision unit 323 Registration unit 324 Storage unit 331 Network interface 332 Processor 333 Memory

Claims

1. A roadside device comprising: means for receiving a message from a first vehicle-mounted device using a first communication method for device-to-device direct communication; and means for forwarding the received message to another roadside device that can communicate with the second vehicle-mounted device using a second communication method for device-to-device direct communication.

2. The roadside unit according to claim 1, wherein the message is a message that notifies information about a vehicle equipped with the first on-board unit.

3. The roadside unit according to claim 2, wherein the message includes a Basic Safety Message (BSM).

4. The roadside device according to any one of claims 1 to 3, wherein one of the first communication method and the second communication method is DSRC and the other is C-V2X PC5.

5. The roadside unit according to any one of claims 1 to 3, wherein the forwarding means forwards the message in accordance with a predetermined forwarding policy.

6. The roadside device according to claim 5, wherein the forwarding policy includes a policy for determining whether or not to forward the message based on the distance between the first vehicle-mounted device and the other roadside device.

7. The roadside unit according to claim 6, wherein the forwarding policy is to forward the message if the distance is shorter than a predetermined value.

8. The roadside unit according to claim 5, wherein the forwarding policy includes a policy for determining whether or not to forward the message based on the priority of the message.

9. The roadside unit according to claim 8, wherein the forwarding policy is to forward the message if the priority of the message is higher than a predetermined value.

10. The roadside unit according to claim 8, wherein the priority is based on the type of vehicle in which the first onboard unit that transmitted the message is mounted.

11. The roadside unit according to claim 8, wherein the priority is based on the type of the message.

12. The roadside unit according to claim 5, wherein the forwarding policy includes a policy that controls how often the message is forwarded.

13. The roadside device according to claim 12, wherein the forwarding policy generates a message to be forwarded based on information contained in a plurality of messages received from the first vehicle-mounted device during a predetermined period.

14. The roadside unit according to claim 13, wherein the forwarding policy generates the message to be forwarded by averaging information contained in the plurality of messages.

15. The roadside device according to claim 12, wherein the forwarding policy forwards a selected message from among a plurality of messages received from the first vehicle-mounted device within a predetermined period of time.

16. The roadside device according to claim 5, wherein the forwarding policy includes a policy for forwarding the message related to the other roadside device based on a moving direction of a vehicle equipped with the first onboard device.

17. The roadside unit according to any one of claims 1 to 3, further comprising means capable of communicating in the second communication method.

18. A roadside device according to any one of claims 1 to 3, wherein the forwarding means forwards the received message to the other roadside device capable of communicating using the first communication method and the second communication method.

19. A roadside unit according to any one of claims 1 to 3, wherein the forwarding means forwards the message via a control device.

20. A roadside unit according to any one of claims 1 to 3, wherein the forwarding means forwards the message via a control device that controls the roadside unit and a control device that controls the other roadside unit.

21. A roadside device according to any one of claims 1 to 3, further comprising: means for storing forwarding information indicating a forwarding relationship with said other roadside devices; and said forwarding means for forwarding said message to said other roadside devices based on said forwarding information.

22. A roadside device according to claim 21, comprising: means for transmitting information about said roadside device to a control device; and means for acquiring information about said other roadside devices from said control device and registering said acquired information in said forwarding information.

23. The roadside device according to claim 21, further comprising means for determining a forwarding relationship with the other roadside device based on information relating to the other roadside device, and registering the result of the determination in the forwarding information.

24. The roadside device according to claim 23, wherein said receiving means receives information relating to said other roadside devices from said first vehicle-mounted device.

25. The roadside device according to claim 24, wherein the receiving means receives information about the other roadside devices from the first vehicle-mounted device that is capable of communicating using the first communication method and the second communication method.

26. A roadside device comprising: means for receiving, from another roadside device, a message that the other roadside device has received from a first vehicle-mounted device using a first communication method for device-to-device direct communication and forwarded; and means for transmitting the received message to a second vehicle-mounted device using a second communication method for device-to-device direct communication.

27. A control device comprising: means for receiving, from a first roadside device, a message received from a first vehicle-mounted device by the first roadside device using a first communication method for direct device-to-device communication; and means for transferring the received message to another control device connected to a second roadside device that can communicate with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

28. A control device comprising: means for receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first vehicle-mounted device using a first communication method for direct device-to-device communication; and means for transmitting the received message to a second roadside device capable of communicating with a second vehicle-mounted device using a second communication method for direct device-to-device communication.

29. An in-vehicle device comprising: means for acquiring information about a first roadside device from a first roadside device using a first communication method for direct communication between devices; and means for notifying a second roadside device of the acquired information about the first roadside device using the first communication method or a second communication method.

30. A system comprising a first roadside device and a second roadside device, wherein the first roadside device comprises: means for receiving a message from a first vehicle-mounted device using a first communication method for device-to-device direct communication; and means for forwarding the received message to the second roadside device capable of communicating with the second vehicle-mounted device using a second communication method for device-to-device direct communication; and the second roadside device comprises: means for receiving from the first roadside device a message that the first roadside device received from the first vehicle-mounted device using the first communication method and forwarded; and means for transmitting the received message to the second vehicle-mounted device using the second communication method.

31. A method for a roadside unit, comprising: receiving a message from a first vehicle-mounted unit using a first communication method for device-to-device direct communication; and forwarding the received message to another roadside unit capable of communicating with the second vehicle-mounted unit using a second communication method for device-to-device direct communication.

32. A method for a roadside device, comprising: receiving, from another roadside device, a message that the other roadside device has received from a first vehicle-mounted device and forwarded using a first communication method for device-to-device direct communication; and transmitting the received message to a second vehicle-mounted device using a second communication method for device-to-device direct communication.

33. A method for a control device, comprising: receiving, from a first roadside device, a message that the first roadside device has received from a first in-vehicle device using a first communication method for direct device-to-device communication; and transferring the received message to another control device connected to a second roadside device that can communicate with a second in-vehicle device using a second communication method for direct device-to-device communication.

34. A method for a control device, comprising: receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first in-vehicle device using a first communication method for direct device-to-device communication; and transmitting the received message to a second roadside device capable of communicating with a second in-vehicle device using a second communication method for direct device-to-device communication.

35. A method for an in-vehicle device, comprising: acquiring information about a first roadside device from a first roadside device using a first communication method for device-to-device direct communication; and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or a second communication method.

36. A program for causing a computer to execute a method for a roadside unit, the method including: receiving a message from a first vehicle-mounted unit using a first communication method for device-to-device direct communication; and forwarding the received message to another roadside unit that can communicate with the second vehicle-mounted unit using a second communication method for device-to-device direct communication.

37. A program for causing a computer to execute a method for a roadside device, the method including: receiving, from another roadside device, a message that the other roadside device has received from a first vehicle-mounted device using a first communication method for device-to-device direct communication and forwarded; and transmitting the received message to a second vehicle-mounted device using a second communication method for device-to-device direct communication.

38. A program for causing a computer to execute a method for a control device, the method including: receiving, from a first roadside device, a message that the first roadside device received from a first in-vehicle device using a first communication method for direct device-to-device communication; and transferring the received message to another control device connected to a second roadside device that can communicate with a second in-vehicle device using a second communication method for direct device-to-device communication.

39. A program for causing a computer to execute a method for a control device, the method including: receiving, from another control device connected to a first roadside device, a message received by a first roadside device from a first in-vehicle device using a first communication method for direct device-to-device communication; and transmitting the received message to a second roadside device capable of communicating with a second in-vehicle device using a second communication method for direct device-to-device communication.

40. A program for causing a computer to execute a method for an in-vehicle device, the method including: acquiring information about a first roadside device from a first roadside device using a first communication method for direct communication between devices; and communicating the acquired information about the first roadside device to a second roadside device using the first communication method or a second communication method.

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