Communication control method and communication device

Abstract

This invention provides a communication control method that enables a vehicle to connect to a wide-area communication network from its onboard communication equipment, even when the vehicle is located in a place where it is impossible to connect to a base station for connecting to a wide-area communication network. [Solution] The communication control method is performed by a communication system 1 comprising a first communication device 10 mounted on a first vehicle X1 and a second communication device 20a mounted on a second vehicle X2a. When the first communication device 10 becomes unable to connect to the wide-area communication network 2, it uses vehicle-to-vehicle communication to send a connection request to the second communication device 20a of the second vehicle X2a, which is capable of connecting to the wide-area communication network 2, requesting a connection to the wide-area communication network 2. When the second communication device 20a receives the connection request, it connects to the wide-area communication network 2, thereby relaying communication between the first communication device 10 and the wide-area communication network 2.

Description

Technical Field

[0001] The present invention relates to a communication control method and a communication apparatus.

Background Art

[0002] There is a system that allows a user to view content using an information processing apparatus in a vehicle by connecting the information processing apparatus mounted on the vehicle to a base station for connecting to a wide area communication network (hereinafter simply referred to as "base station"). In such a system, when the vehicle moves to a location where connection to the base station is not possible, for example, into a tunnel, the user becomes unable to view the content.

[0003] In view of this, there is a technique of transmitting content that is highly likely to be used by the information processing apparatus in the vehicle at a location where connection to the base station is not possible, to the information processing apparatus before the vehicle reaches the location where connection to the base station is not possible (for example, Patent Document 1). By using this technique, the user can continue to view desired content even if the vehicle moves to a location where connection to the base station is not possible.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] The above-described technique has a problem that although a user can view the content transmitted in advance at a location where connection to the base station is not possible, the user cannot view other content.

[0006] The present invention has been made in view of the above problems, and its object is to provide a communication control method and a communication device that enables connection to a wide-area communication network from a communication device mounted on a vehicle, even when the vehicle is in a location where it is not possible to connect to a base station for connecting to a wide-area communication network. [Means for solving the problem]

[0007] A communication control method according to one aspect of the present invention is performed by a communication system comprising a first communication device mounted on a first vehicle and a second communication device mounted on a second vehicle. When the first communication device is able to connect to a wide-area communication network, it connects to the wide-area communication network. When it is unable to connect to the wide-area communication network, it uses vehicle-to-vehicle communication, in which communication devices mounted on vehicles communicate directly with each other, to send a connection request to the second communication device of the second vehicle, which is able to connect to the wide-area communication network, requesting a connection to the wide-area communication network. Upon receiving the connection request, the second communication device connects to the wide-area communication network, thereby relaying communication between the first communication device and the wide-area communication network. [Effects of the Invention]

[0008] According to one aspect of the present invention, even when a vehicle is located in a place where it is not possible to connect to a base station for connecting to a wide-area communication network, it becomes possible to connect to a wide-area communication network from a communication device mounted on the vehicle. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an overall diagram showing the configuration of a communication system using the communication device according to this embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the communication device according to this embodiment. [Figure 3] Figure 3 is a flowchart showing the processes performed by the communication device according to this embodiment. [Figure 4] Figure 4 is a sequence diagram showing the process that a communication device performs with other communication devices when identifying a master unit. [Modes for carrying out the invention]

[0010] A communication system and a communication control method according to one embodiment will be described with reference to the drawings. In this embodiment, the communication system controls the connection of communication from communication devices mounted on each vehicle traveling on a road to a wide-area communication network.

[0011] Figure 1 is an overall diagram showing the configuration of the communication system 1 according to this embodiment. The communication system 1 comprises communication devices 40b, 40a, 10, 30a, 30b, 30c, etc. mounted on multiple vehicles X4b, X4a, X1, X3a, X3b, X3c, X3d, X3e, X2a, X2b, X2c, etc. traveling on a road R, a Web server 3 connected to a wide-area communication network 2, and a base station 4 provided by a telecommunications carrier for connecting to the wide-area communication network 2. In Figure 1, only one Web server and one base station are shown for the sake of simplicity, but multiple Web servers and base stations may be connected to the wide-area communication network 2. The wide-area communication network 2 may be, for example, the internet. The wide-area communication network 2 may utilize mobile communication functions such as 4G / LTE or 5G.

[0012] Road R has a tunnel TN. Road R is currently congested, with the first vehicle X1 located closest to the tunnel entrance EN inside TN, and the second group of vehicles X2 (second vehicles X2a, X2b, and X2c) located close to the tunnel exit EX outside TN. Between the first vehicle X1 and the second vehicle X2 is the third group of vehicles X3 (third vehicles X3a, X3b, X3c, X3d, and X3e), and the fourth group of vehicles X4 (fourth vehicles X4a and X4b) located close to the tunnel entrance EN outside TN. Specifically, the vehicles are located on Road R in the following order: fourth vehicle X4b, fourth vehicle X4a, first vehicle X1, third vehicle X3a, third vehicle X3b, third vehicle X3c, third vehicle X3d, third vehicle X3e, second vehicle X2a, second vehicle X2b, and second vehicle X2c.

[0013] These vehicles X4b, X4a, X1, X3a, X3b, X3c, X3d, X3e, X2a, X2b, and X2c have the same configuration.

[0014] The configuration of the first vehicle X1 will be described with reference to Figure 2. The first vehicle X1 is equipped with a communication device 10 as the first communication device, a position sensor 101, and a user terminal 102. The communication device 10 has a network communication unit 11, an inter-vehicle communication unit 12, a terminal communication unit 13, a list storage unit 14, and a control unit 15.

[0015] The network communication unit 11 connects to the wide-area communication network 2 via the base station 4. The vehicle-to-vehicle communication unit 12 communicates with communication devices mounted on other vehicles within a predetermined distance using short-range wireless communication such as Wi-Fi (registered trademark). The terminal communication unit 13 communicates with the user terminal 102 located in vehicle X1 using short-range wireless communication such as Wi-Fi or Bluetooth (registered trademark). The list storage unit 14 stores a list of other communication devices (communication device list) that are generated by the control unit 15 as described later and used when connecting to the wide-area communication network 2 via vehicle-to-vehicle communication.

[0016] The control unit 15 is a microcomputer (controller) mainly composed of a CPU, memory, and input / output interface. The memory contains a computer program (communication application) that enables the information terminal to function as a communication device in the communication system 1. By executing the computer program, the control unit 15 realizes one or more functions of the communication device. When it is possible to connect from the network communication unit 11 to the wide-area communication network 2, the control unit 15 connects to the wide-area communication network 2. If it becomes impossible to connect from the network communication unit 11 to the wide-area communication network 2, the control unit 15 identifies other vehicles located in positions where it is possible to connect to the wide-area communication network 2, using vehicle-to-vehicle communication where communication devices mounted on vehicles communicate directly with each other. The control unit 15 connects to the wide-area communication network 2 via the communication device of the identified other vehicle. The control unit 15 also holds map information, including the entrance and exit locations of tunnels.

[0017] The position sensor 101 obtains the current position information of the first vehicle X1 by, for example, receiving GNSS signals from multiple satellites for the Global Navigation Satellite System (GNSS) and calculating position information. One example of GNSS is GPS (Global Positioning System).

[0018] Vehicles other than the first vehicle X1, specifically, the second vehicles X2a, X2b, and X2c, the third vehicles X3a, X3b, X3c, and X3d, and the fourth vehicles X4a and X4b, are each also equipped with a communication device having the same configuration as the communication device 10, and a position sensor. Each vehicle may also be equipped with a user terminal capable of communicating with the communication device. In FIG. 1, the communication devices 20a, 20b, and 20c respectively mounted on the second vehicles X2a, X2b, and X2c, the communication devices 30a, 30b, 30c, 30d, and 30e respectively mounted on the third vehicles X3a, X3b, X3c, and X3d, and the communication devices 40a and 40b respectively mounted on the fourth vehicles X4a and X4b are representatively shown.

[0019] The processing executed in the communication system 1 according to the present embodiment will be described. In the example shown below, as illustrated in FIG. 1, a case where a plurality of vehicles stuck in traffic on road R are traveling in the direction of arrow D will be described.

[0020] The processing executed by the communication device 10 of the first vehicle X1 traveling on road R will be described with reference to the flowchart of FIG. 3. When the first vehicle X1 is ahead of the entrance EN of the tunnel TN, that is, outside the tunnel TN, the communication strength between the network communication unit 11 and the base station 4 is equal to or higher than a predetermined value, and the communication device 10 can connect to the wide area communication network 2. At this time, the control unit 15 of the communication device 10 connects to the wide area communication network 2 via the network communication unit 11 and the base station 4 (S1). Thereby, the control unit 15 can access the Web server 3 via the wide area communication network 2. Note that the communication strength between the communication device mounted on any one of the vehicles and the base station 4 is hereinafter referred to as "external communication strength".

[0021] When the first vehicle X1 moves and enters the tunnel TN from the entrance EN to reach the state shown in FIG. 1, the external communication strength between the network communication unit 11 and the base station 4 becomes less than the predetermined value, which disables the connection from the control unit 15 to the wide area communication network 2.

[0022] The control unit 15 determines, based on the external communication strength, whether or not the connection from the network communication unit 11 to the wide area communication network 2 has become unavailable (S2). When detecting that the connection from the network communication unit 11 to the wide area communication network 2 has become unavailable (S2: YES), the control unit 15 determines whether or not the first vehicle X1 is inside the tunnel TN based on the position information of the first vehicle X1 acquired by the position sensor 101 and the map information (S3). When determining that the first vehicle X1 is inside the tunnel TN (S3: YES), the control unit 15 executes a specifying process for specifying a communication device to be used as a parent device for connection to the wide area communication network 2 from among the communication devices of other surrounding vehicles (S4).

[0023] When the first vehicle X1 enters the tunnel TN, as shown in FIG. 1, a group of third vehicles X3 (third vehicles X3a, X3b, X3c, X3d, and X3e) are arranged in sequence between the first vehicle X1 and the exit EX of the tunnel TN. In addition, a group of second vehicles X2 (second vehicles X2a, X2b, and X2c) are arranged in sequence outside the tunnel TN ahead of the exit EX in the traveling direction. Further, a group of fourth vehicles X4 (fourth vehicles X4a and X4b) are arranged in sequence outside the tunnel TN before the entrance EN.

[0024] The specifying process executed by the control unit 15 of the communication device 10 when the first vehicle X1 enters the tunnel TN will be described with reference to the sequence diagram of FIG. 4. Upon starting the specifying process, the control unit 15 specifies, as the vehicle-to-vehicle communication destination communication device, any one of the communication devices mounted on other vehicles on the road R that has a short-range wireless communication strength (hereinafter referred to as "short-range communication strength") for performing vehicle-to-vehicle communication with the vehicle-to-vehicle communication unit 12 equal to or greater than a predetermined value. Here, the control unit 15 specifies, as the vehicle-to-vehicle communication destination, the communication device 30a of the third vehicle X3a, which has the shortest distance to the communication device 10 in the direction of the exit EX of the tunnel TN, from among the communication devices with a short-range communication strength equal to or greater than the predetermined value.

[0025] The control unit 15 requests a vehicle-to-vehicle communication connection from the identified communication device 30a. When the communication device 30a responds, vehicle-to-vehicle communication is established between the communication device 10 and the communication device 30a. Once vehicle-to-vehicle communication is established between the communication device 10 and the communication device 30a, the control unit 15 obtains external communication strength and location information related to the communication device 30a from the communication device 30a (S11).

[0026] If the control unit 15 determines that the external communication strength of the identified communication device 30a is below a predetermined value and that the vehicle X3a carrying the communication device 30a is inside a tunnel based on the location information of the communication device 30a, it recognizes the communication device 30a as a relay device for connecting to the wide-area communication network 2 (S12).

[0027] Here, the control unit 15 generates a list of communication devices that contains information indicating that the communication device 30a is a relay device, and stores it in the list storage unit 14. The information indicating that the communication device 30a is a relay device includes the external communication strength of the communication device 30a, the vehicle-to-vehicle communication strength between the communication device 10 and the communication device 30a, and the location information of the communication device 30a. The control unit 15 transmits the generated list of communication devices to the communication device 30a with which vehicle-to-vehicle communication has been established, thereby sharing the information of the communication device list with the communication device 30a (S13).

[0028] Communication device 30a detects, based on the communication device list, that it has been recognized as a repeater by communication device 10. Since the master unit of communication device 10 has not yet been identified, communication device 30a determines that it is necessary to continue the process of identifying the master unit and executes the same process as in steps S11 to S13. As a result, communication device 30a identifies communication device 30b as a new vehicle-to-vehicle communication destination and establishes vehicle-to-vehicle communication with communication device 30b. Communication device 30a obtains the external communication strength related to communication device 30b, the vehicle-to-vehicle communication strength between communication device 30a and communication device 30b, and the location information of communication device 30b from communication device 30b and transmits them to communication device 10 (S14).

[0029] Based on the acquired information, the control unit 15 of the communication device 10 determines that the external communication strength of the communication device 30b is below a predetermined value and that the vehicle X3b carrying the communication device 30b is inside a tunnel. Based on this determination, the control unit 15 recognizes the communication device 30b as a repeater for connecting to the wide-area communication network 2 (S15).

[0030] The control unit 15 updates the communication device list stored in the list storage unit 14 by adding information that communication device 30b is a relay device. The control unit 15 shares the communication device list information with communication devices 30a and 30b, with whom vehicle-to-vehicle communication has been established, by transmitting the updated communication device list (S16).

[0031] Similarly, the control unit 15 continues the identification process until it detects a communication device with an external communication strength equal to or greater than a predetermined value, and sequentially causes the newly connected communication devices via vehicle-to-vehicle communication to perform the same processes as in steps S11 to S13.

[0032] While the specific processing is being executed sequentially, the control unit 15 acquires external communication strength, vehicle-to-vehicle communication strength, and location information from the second communication device, the communication device 20a (S17). The control unit 15 determines that the external communication strength of the communication device 20a is above a predetermined value and that the vehicle X2 equipped with the communication device 20a is outside the tunnel TN. Based on the determination result, the control unit 15 recognizes the communication device 20a as a master unit for connecting to the wide-area communication network 2 (S18).

[0033] The control unit 15 updates the communication device list stored in the list storage unit 14 by adding information that communication device 20a is the master device. The control unit 15 transmits the updated communication device list to the communication devices 30a, 30b, 30c, 30d, 30e, and 20a with which vehicle-to-vehicle communication has been established, thereby sharing the communication device list information with these communication devices 30a, 30b, 30c, 30d, 30e, and 20a (S19).

[0034] When the control unit 15 identifies communication device 20a as the master unit, it returns to the flowchart in Figure 3. The control unit 15 refers to the list of communication devices stored in the list storage unit 14 and sends a connection request to communication device 30b to connect to the wide-area communication network 2 via these communication devices, designating communication devices 30a to 30e as repeaters and communication device 20a as the master unit.

[0035] Communication devices 30b to 30e refer to their respective stored lists of communication devices and sequentially send connection requests to the connected communication devices. When communication device 20a receives a connection request, it connects to the wide-area communication network 2, thereby relaying communication between communication device 10 and the wide-area communication network 2. As a result, communication device 10 is connected to the wide-area communication network 2 via communication devices 30a, 30b, 30c, 30d, 30e, and 20a, and becomes able to access the Web server 3 (S5).

[0036] Subsequently, when the first vehicle X1 moves and exits the tunnel TN from exit EX, the external communication strength of the communication device 10 becomes above a predetermined value. When the external communication strength of the communication device 10 becomes above a predetermined value (S6:YES), the network communication unit 11 can connect to the wide-area communication network 2, so the process returns to step S1, and the control unit 15 connects to the wide-area communication network 2. Once the control unit 15 connects to the wide-area communication network 2, vehicle-to-vehicle communication between communication devices 30a, 30b, 30c, 30d, 30e, and 20a is disconnected.

[0037] In step S5, when the communication device 10 is connected to the wide-area communication network 2 using communication devices 30b to 30e as repeaters and communication device 20a as the master unit, the communication device 10 may appropriately switch the repeaters and master unit used depending on the movement status of each vehicle.

[0038] Specifically, when the third vehicle X3e exits the tunnel TN and becomes able to connect to the wide-area communication network 2 from the network communication unit 31e, the communication device 10 switches the communication device 30e from a repeater to a master unit and disconnects the communication device 20a from being a master unit. This makes it possible to establish a communication path more easily by using the communication device located as close as possible to the communication device 10 as the master unit.

[0039] Furthermore, in step S5, when the communication device 10 connects to the wide-area communication network 2, if the communication device 10 can communicate directly with the communication device 20a, it may connect to the wide-area communication network 2 by directly communicating with the communication device 20a without going through the communication devices 30b to 30c.

[0040] Furthermore, although step S11 described a case in which the communication device 10 identifies the communication device of another vehicle located in the direction of the tunnel exit EX as the communication device to communicate with, it is not limited to this, and may also identify the communication device of another vehicle located in the direction of the tunnel entrance EN. In this case, it may also identify the communication device located closer to the first vehicle X1 among the communication devices mounted on vehicles located within a predetermined distance from the tunnel entrance EN or exit EX.

[0041] Alternatively, when creating a communication device list, each vehicle's communication device may obtain a communication device list already generated by the communication devices of other vehicles located within the tunnel (TN), and use this to create a communication device list that its own communication device will use to connect to the wide-area communication network 2.

[0042] Furthermore, in step S18, when the communication device 10 recognizes the master unit, if it determines that the communication load of the closest communication device 20a, which has an external communication strength of a predetermined value or higher, is high, it may designate a communication device other than communication device 20a as the master unit. This communication device other than communication device 20a is a communication device of another vehicle that can connect to the wide-area communication network 2, selected by communication device 20a, for example, communication device 20b of vehicle X2b. Alternatively, when the communication device 10 attempts to identify the master unit, it may designate the communication device that has the lowest communication load among vehicles X2a, X2b, and X2c in the second vehicle X2 group, which includes communication device 20a, by sending and receiving information, as the master unit of the communication device 10.

[0043] According to the above embodiment, the communication control method is performed by a communication system comprising a first communication device mounted on a first vehicle and a second communication device mounted on a second vehicle. When the first communication device is able to connect to a wide-area communication network, it connects to the wide-area communication network. When it is unable to connect to the wide-area communication network, it uses vehicle-to-vehicle communication, in which communication devices mounted on vehicles communicate directly with each other, to send a connection request to the second communication device of the second vehicle, which is able to connect to the wide-area communication network, requesting a connection to the wide-area communication network. Upon receiving the connection request, the second communication device connects to the wide-area communication network, thereby relaying communication between the first communication device and the wide-area communication network.

[0044] This allows the communication device to connect to the wide-area communication network even when the vehicle is in a location where it cannot connect to a base station for connecting to the wide-area communication network, by using a communication device installed in another vehicle as a relay.

[0045] Furthermore, the first communication device may identify the second vehicle when connection to the wide-area communication network becomes impossible and the first vehicle is located inside a tunnel. This allows the communication device to be configured to connect to the wide-area communication network using a communication device installed in another vehicle only when the vehicle enters a tunnel and connection to the wide-area communication network becomes impossible for a predetermined period of time or longer.

[0046] Furthermore, the second vehicle may be located outside the tunnel. This allows the communication equipment to be configured to connect to the wide-area communication network using the communication equipment mounted on the second vehicle when the second vehicle is located outside the tunnel and can reliably communicate with the base station.

[0047] Furthermore, if at least one third vehicle is present between the first and second vehicles, the first communication device may communicate with the second communication device via vehicle-to-vehicle communication with the third communication device installed in the third vehicle. This allows the communication device to be configured to connect to a wide-area communication network using communication devices installed in multiple vehicles, even when there are long distances where connection to a base station is not possible.

[0048] Furthermore, if there are multiple third vehicles between the first and second vehicles, the first communication device may identify the second communication device by sequentially connecting the multiple third communication devices and the second communication device mounted on the multiple third vehicles via vehicle-to-vehicle communication, and generate a communication device list that stores the identification information of the multiple third communication devices that have been sequentially connected via vehicle-to-vehicle communication. Using this communication device list, vehicle-to-vehicle communication with the second communication device can be performed via the multiple third communication devices. This allows the communication device to be configured to connect to a wide-area communication network with high accuracy using communication devices mounted on multiple vehicles, even in cases where there are long distances where it is impossible to connect to a base station, such as in long-distance tunnels.

[0049] Furthermore, if at least one third vehicle is present between the first and second vehicles, the first communication device may communicate directly with the second communication device without going through the third communication device installed in the third vehicle. This allows the communication device to reduce the number of repeaters required when connecting to a wide-area communication network, thereby reducing communication lag.

[0050] Furthermore, the second vehicle may be the vehicle closest to the first vehicle among those located within a predetermined distance from the tunnel entrance or exit. This allows the communication device to efficiently connect to the wide-area communication network using the communication device installed on the other vehicle located closer.

[0051] Furthermore, the second communication device may be selected from among the communication devices of multiple vehicles located in positions where connection to the wide-area communication network is possible, depending on the communication load situation. This makes it possible to avoid a situation where a single second communication device is subjected to a heavy load when there are many communication devices located in places where connection to the wide-area communication network is not possible.

[0052] As described above, embodiments of the present invention have been presented, but the statements and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. [Explanation of Symbols]

[0053] 1. Communication System 2. Wide-area telecommunications network 3 Web Server 4 base station 10, 20a~20c, 30a~30e, 40a, 40b Communication device 11, 21a-21c, 31a-31e, 41a, 41b Network Communication Section 12, 22a~22c, 32a~32e, 42a, 42b Vehicle-to-vehicle communication section 13, 23a-23c, 33a-33e, 43a, 43b Terminal communication section 14, 24a-24c, 34a-34e, 44a, 44b List memory section 15, 25a~25c, 35a~35e, 45a, 45b Control Unit 101, 201a~201c, 301a~301e, 401a, 401b Position Sensors 102, 202a~202c, 302a~302e, 402a, 402b User Terminals

Claims

1. A communication control method performed by a communication system comprising a first communication device mounted on a first vehicle and a second communication device mounted on a second vehicle, The first communication device, When connection to a wide-area communication network is possible, connect to the said wide-area communication network. If connection to the wide-area communication network becomes impossible, a connection request is sent to the second communication device of the second vehicle, which is capable of connecting to the wide-area communication network, using vehicle-to-vehicle communication, where communication devices mounted on vehicles communicate directly with each other. The second communication device, A communication control method that, upon receiving the aforementioned connection request, connects to the aforementioned wide-area communication network to relay communication between the first communication device and the aforementioned wide-area communication network.

2. The first communication device is The communication control method according to claim 1, which identifies the second vehicle when connection to the wide-area communication network becomes impossible and the first vehicle is located inside a tunnel.

3. The communication control method according to claim 2, wherein the second vehicle is located outside the tunnel.

4. The first communication device is The communication control method according to claim 1, wherein, if at least one third vehicle is present between the first vehicle and the second vehicle, vehicle-to-vehicle communication is performed with the second communication device via vehicle-to-vehicle communication with a third communication device mounted on the third vehicle.

5. The first communication device is The communication control method according to claim 4, wherein, when there are multiple third vehicles between the first vehicle and the second vehicle, the second communication device is identified by sequentially connecting the multiple third communication devices mounted on the multiple third vehicles and the second communication device via vehicle-to-vehicle communication, a communication device list is generated which stores the identification information of the multiple third communication devices that have been sequentially connected via vehicle-to-vehicle communication, and vehicle-to-vehicle communication with the second communication device is performed via the multiple third communication devices using the communication device list.

6. The first communication device is The communication control method according to claim 1, wherein, if at least one third vehicle is present between the first vehicle and the second vehicle, vehicle-to-vehicle communication is performed directly with the second communication device without going through the third communication device mounted on the third vehicle.

7. The communication control method according to claim 3, wherein the second vehicle is the vehicle closer to the first vehicle among vehicles located within a predetermined distance from the entrance or exit of the tunnel.

8. The second communication device is The communication control method according to claim 1, wherein a communication device of a plurality of vehicles located in a position where connection to the wide-area communication network is possible is selected according to the communication load status.

9. A communication control method performed by a communication device mounted on the first vehicle, When connection to a wide-area communication network is possible, connect to the said wide-area communication network. A communication control method that, when connection to the aforementioned wide-area communication network becomes impossible, connects to the aforementioned wide-area communication network via a second communication device mounted on a second vehicle that is capable of connecting to the aforementioned wide-area communication network using vehicle-to-vehicle communication, where communication devices mounted on vehicles communicate directly with each other.

10. A communication device installed in the first vehicle, The controller is equipped with a controller, When connection to a wide-area communication network is possible, connect to the said wide-area communication network. A communication device that, when connection to the aforementioned wide-area communication network becomes impossible, connects to the aforementioned wide-area communication network via a second communication device mounted on a second vehicle, which is capable of connecting to the aforementioned wide-area communication network using vehicle-to-vehicle communication, where communication devices mounted on vehicles communicate directly with each other.

Images