JP2008197704A - Inter-vehicle communication device - Google Patents

Abstract

An object of the present invention is to suppress an increase in communication traffic in inter-vehicle communication.
An own vehicle communicable vehicle detecting means for detecting a vehicle communicable with the own vehicle, an information discontinuity judging means for judging whether or not information from a specific vehicle is continuously received, The communicable vehicle information adding means 18 for adding the vehicle information detected by the own vehicle communicable vehicle detecting means 14 to the information transmitted to the other vehicle by the transmitting means 12, and the own vehicle existing around the specific vehicle Vehicles capable of communicating with other vehicles for detecting vehicles that can communicate with each other, and vehicles capable of communicating with other vehicles when the information discontinuity detecting means 22 determines that information from the specific vehicle is not continuously received. The vehicle detected by the detection means 15 is designated as a relay vehicle, and information on the own vehicle is transmitted. The relay vehicle designated as the relay vehicle relays information.
[Selection] Figure 1

Description

  The present invention relates to an inter-vehicle communication device.

  In a vehicle-to-vehicle communication system that exchanges information between vehicles and supports vehicle travel, for example, when the host vehicle is waiting for a right turn at an intersection, the vehicle to be communicated is behind another vehicle. In some cases, communication cannot be performed. As countermeasures, methods such as installing a repeater on the roadside or relaying another vehicle for communication are adopted.

For example, a vehicle that has entered an intersection transmits its information that it can operate as a relay vehicle to other surrounding vehicles by an in-vehicle communication device, and the other vehicle that has received this information designates the vehicle as a relay vehicle. Is transmitted (for example, refer to Patent Document 1).
JP 2006-148322 A

  However, in the inter-vehicle communication by the conventional relay vehicle, even when there is no vehicle that can be dangerous for the host vehicle behind the vehicle that hinders communication, information is transmitted by relaying the vehicle in the intersection. There is a problem that traffic increases.

  Accordingly, the present invention provides a vehicle-to-vehicle communication device capable of relaying and communicating with a vehicle only when there is a vehicle that may be dangerous for the host vehicle behind the vehicle.

The vehicle-to-vehicle communication device according to the present invention employs the following means in order to solve the above problems.
The invention according to claim 1 is a transmission means for transmitting information to a vehicle outside the own vehicle (for example, transmission means 12 in an embodiment described later) and a reception means for receiving information from a vehicle outside the own vehicle ( For example, receiving means 13) in an embodiment described later, and relay means for relaying information received by the receiving means to a vehicle outside the host vehicle by the transmitting means (for example, relay means 21 in an embodiment described later) , A vehicle-to-vehicle communication device (for example, a vehicle-to-vehicle communication device 1A or 1B in an embodiment to be described later), and a vehicle-detectable vehicle detection means (for example, described later) that detects a vehicle that can communicate with the vehicle. Information discontinuity determination for determining whether or not the information from the specific vehicle received by the receiving means is continuously received by the own vehicle communicable vehicle detecting means 14) in the embodiment. A communicable vehicle that adds vehicle information detected by the vehicle (eg, information discontinuity determination unit 22 in the embodiment described later) and the vehicle-communicable vehicle detection unit to information transmitted to the outside by the transmission unit. Information adding means (for example, communicable vehicle information adding means 18 in the embodiments described later) and other vehicle communicable vehicles that detect vehicles that are in the vicinity of the specific vehicle and can communicate with the own vehicle. Detection means (for example, other vehicle communicable vehicle detection means 15 in the embodiment described later), and when it is determined by the information discontinuity detection means that information from the specific vehicle is not continuously received, The vehicle detected by the other vehicle communicable vehicle detection means is designated as a relay vehicle, information is transmitted by the transmission means, and the relay means transmits the information. A vehicle-to-vehicle communication apparatus characterized by relaying if more vehicle is instructed to relay information.

  The invention according to claim 2 is the invention according to claim 1, wherein the first vehicle (for example, a vehicle A in an embodiment described later) is the host vehicle, and the second vehicle (for example, in an embodiment described later). When the vehicle B) is the specific vehicle and the third vehicle (for example, the vehicle C in the embodiment described later) is the relay vehicle, the second vehicle is transmitted from the received first vehicle. When the transmitted information and the information transmitted through the third vehicle are the same information, the information is transmitted by the transmission means without instructing the third vehicle as a relay vehicle. .

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the first vehicle (for example, a vehicle A in an embodiment to be described later) is set as the own vehicle, and the second vehicle (for example, described later). When the vehicle B) in the embodiment to be used is the specific vehicle and the third vehicle (for example, the vehicle C in the embodiment described later) is the relay vehicle, the second vehicle is the third vehicle. When only the information transmitted via relay is received, the third vehicle is designated as a relay vehicle, and the information is transmitted by the transmission means.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the transmission means transmits information every first predetermined time, and the information discontinuity determination means includes: It is determined that information from the specific vehicle is not continuously received when information from the specific vehicle received by the receiving unit is not received for a second predetermined time longer than the first predetermined time. To do.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the transmission means transmits the information by adding a serial number that is updated each time it is transmitted, and the information The discontinuity determining means determines that information from the specific vehicle is not continuously received when a serial number of information from the specific vehicle received by the receiving means is missing a predetermined value or more. .

According to the first aspect of the present invention, it is possible to detect the presence or absence of a vehicle (that is, a specific vehicle) whose information is not continuously received based on the actual communication state, and to identify the vehicle. .
In addition, a relay vehicle is specified only when there is a specific vehicle for which information is not continuously received, information on the own vehicle is transmitted to the specific vehicle via the relay vehicle, and a specific vehicle for which information is not continuously received When it does not exist, no relay vehicle is designated and communication via the relay vehicle is not performed, so that only minimal communication can be performed, and as a result, increase in communication traffic can be suppressed.

According to the second aspect of the invention, the second vehicle that relays the third vehicle and receives the information of the first vehicle promptly transmits the information of the second vehicle without relaying the information of the third vehicle. It can be transmitted to the first vehicle.
According to the third aspect of the invention, the second vehicle that relays the third vehicle and receives the information of the first vehicle relays the information of the second vehicle to the first vehicle. Can be reliably transmitted to other vehicles.

According to the invention according to claim 4, since it is determined that the information from the specific vehicle is not continuously received when the information on the specific vehicle is not received for the second predetermined time or more, there is a state in which the information on the specific vehicle is not received. If it is less than the second predetermined time, communication via the relay vehicle is not performed, and the frequency of communication via the relay vehicle can be suppressed.
According to the invention of claim 5, since it is determined that the information from the specific vehicle is not continuously received when the serial number of the information from the specific vehicle is missing a predetermined value or more, the information from the specific vehicle When the missing serial number is less than a predetermined value, communication via the relay vehicle is not performed, and the frequency of communication via the relay vehicle can be suppressed.

Embodiments of a vehicle-to-vehicle communication device according to the present invention will be described below with reference to the drawings of FIGS.
As shown in FIG. 1, the inter-vehicle communication devices 1 </ b> A and 1 </ b> B include the own vehicle information detecting unit 11, the transmitting unit 12, the receiving unit 13, the own vehicle communicable vehicle detecting unit 14, and another vehicle communicable vehicle detection. Means 15, relay vehicle setting means 17, communicable vehicle information addition means 18, travel support determination means 19, information provision means 20, and information discontinuity determination means 22 are configured.

  The own vehicle information detection means 11 is, for example, a vehicle speed sensor that detects the traveling speed (vehicle speed) of the own vehicle, or a GPS (Global Positioning System) that measures the position of the vehicle using an artificial satellite, for example. Positioning signals such as signals, position signals transmitted from information transmission devices outside the host vehicle, magnetic action with, for example, a base point marker placed on the road, and further detection results of an appropriate gyro sensor, acceleration sensor, etc. Based on the position sensor that detects the current position and traveling direction of the host vehicle, the yaw angle (rotational angle around the vertical axis of the vehicle center of gravity), yaw rate (rotational angular velocity around the vertical axis of the vehicle center of gravity) and steering angle ( Each sensor etc. which detect the direction and magnitude | size of the steering angle which the driver input are comprised. The own vehicle information detection unit 11 outputs the detected own vehicle information to the transmission unit 12 and the travel support determination unit 19.

The transmission means 12 transmits various information of the host vehicle and the vehicle that has requested relaying to a vehicle outside the host vehicle, that is, another vehicle at regular time intervals (for example, 100 msec).
The receiving means 13 receives various types of information transmitted from other vehicles, and the received information is sent to the own vehicle communicable vehicle detecting means 14, the other vehicle communicable vehicle detecting means 15, the communicable vehicle information adding means 18, and the driving support. It outputs to the determination means 19 and the information discontinuity determination means 22.
The transmission unit 12 and the reception unit 13 function as a relay unit 21 that relays information received by the reception unit 13 to other vehicles by the transmission unit 12 when the host vehicle is designated as a relay vehicle, as will be described later.

  Here, the information transmitted / received by vehicle-to-vehicle communication will be described. As shown in the transmission data table of FIG. 2, the transmission data transmitted by the transmission source vehicle includes (1) serial number, (2) own vehicle ID, (3) vehicle ID requesting relay, and (4) vehicle type. , (5) vehicle position.

The serial number is a serial number that is updated by adding one each time the own vehicle transmits data.
The own vehicle ID is an ID unique to the vehicle set in advance for the own vehicle.
The vehicle ID that requests relay is the vehicle ID of the vehicle that requests relay of communication when information of other vehicles is lost for a long time, as will be described later, and is not set when relay is not requested.
The vehicle type is an ID representing a preset vehicle type. For example, “1” is an ID of a normal vehicle, “2” is an ID of a small vehicle, “3” is an ID of a large vehicle, and “2” is an ID of a motorcycle. 4 ”etc.
The vehicle position is a latitude / longitude indicating the current position of the host vehicle detected by the host vehicle information detection unit 11.

  Further, the vehicle requested to relay transmits the relay data shown in the relay data table of FIG. 3 in addition to the own vehicle data of FIG. The relay data includes (1) a serial number of a vehicle that has requested relay (hereinafter referred to as a transmission source vehicle), (2) a vehicle ID of the transmission source vehicle, (3) a relayed vehicle ID, and (4) a transmission source vehicle. Vehicle type, (5) vehicle position of the transmission source vehicle.

For example, as shown in FIG. 4, at the intersection P where the road R1 and the road R2 intersect, the vehicle A (first vehicle) stops and waits for a right turn from the road R1 to the road R2, and the road R1 When the vehicles B and C are traveling straight on the opposite lane toward the intersection P, the own vehicle data corresponding to FIG. 2 transmitted by the vehicles A, B and C is as shown in FIGS. 6, 7 and 8, respectively. It is. 6 and 7 show an example in which the vehicles A and B set the vehicle C as a relay vehicle, and FIG. 8 shows an example in which the vehicle C does not set a relay vehicle. The setting of the relay vehicle will be described later.
Further, for example, the relay data transmitted by the vehicle C when the vehicle C is designated as a relay vehicle from the vehicle A is as shown in FIG.

The own vehicle communicable vehicle detecting unit 14 detects a vehicle communicable with the own vehicle based on the information received by the receiving unit 13 and outputs the detected vehicle to the relay vehicle setting unit 17 and the communicable vehicle information adding unit 18.
The information discontinuity determination unit 22 determines whether information from another vehicle that has received the information is continuously received based on the history of information received by the reception unit 13.

  For example, in the example of the vehicles A, B, and C shown in FIG. 4, when the vehicle C traveling ahead of the vehicle B is a large vehicle, when the vehicle C passes the vicinity of the vehicle A, the vehicle The presence of C changes the reception electric field strength of the radio wave transmitted from the vehicle B in the vehicle A. When the reception electric field strength is below a certain level, the vehicle A cannot receive the information on the vehicle B. An intermittent reception state is established (see FIG. 5). When such a reception state is reached, the information discontinuity determination unit 22 of the vehicle A determines that the information from the vehicle B is not continuously received. In this case, the vehicle A determines that the vehicle B is behind the vehicle C.

  Based on the “vehicle position” of the information received by the receiving means 13, the other vehicle communicable vehicle detecting means 15 is a vehicle that exists in the vicinity of a specific vehicle that cannot receive information continuously and can communicate with the own vehicle. Detect and output to the relay vehicle setting means 17. In the example of the vehicles A, B, and C described above, the vehicle A detects the vehicle C that exists in the vicinity of the specific vehicle B for which information is not continuously received and can communicate with the own vehicle (vehicle A). To do.

  The relay vehicle setting means 17 selects a relay vehicle from the vehicles detected by the other vehicle communicable vehicle detection means 15 when the information discontinuity determination means 22 determines that the information on the specific vehicle cannot be received continuously. Set and output to transmission means 12. For example, the relay vehicle setting means 17 of the vehicle A sets the vehicle C as a relay vehicle. Then, the vehicle ID of the vehicle C is set as the “vehicle ID of the vehicle requesting relay” of the own vehicle data of the vehicle A (see FIG. 6). The same applies to the vehicle B (see FIG. 7).

  The communicable vehicle information adding means 18 designates the vehicle detected by the own vehicle communicable vehicle detection means 14 and requested to be relayed when the relay is requested by designating the own vehicle as a relay vehicle. Is output to the transmission means 12. As a result, the vehicle C requested to relay transmits the own vehicle data and the information of the vehicle that has requested the relay (relay data) to the outside by the transmission unit 12.

  In the example of the vehicles A, B, and C described above, when the vehicle C is not requested to relay from any vehicle, only the own vehicle data of the vehicle C shown in FIG. For example, when the vehicle C is requested to relay from the vehicle A, the vehicle C transmits the own vehicle data of the vehicle C shown in FIG. 8 and the relay data shown in FIG. Send to other vehicle. In the relay data transmitted by the vehicle C shown in FIG. 9, the vehicle ID of the vehicle C is set as the “relayed vehicle ID”, and the data of the vehicle A received by the vehicle C from the vehicle A is set as it is for the other data. Is done.

  The vehicle B that has received the relay data recognizes that the vehicle ID of the vehicle C is received by relaying the vehicle C because the vehicle ID of the vehicle C is set as the “relayed vehicle ID” information.

  The driving support determination means 19 performs various determination processes for supporting the traveling of the host vehicle. For example, it is determined whether or not there is a vehicle that goes straight on the opposite lane of the host vehicle as a right turn support. Various determinations such as The driving support determination unit 19 outputs the determination result to the information providing device 20.

  The information providing device 20 notifies the vehicle occupant of the determination result of the driving support determining means 19, and is composed of, for example, a display device that displays predetermined alarm information, a speaker that emits predetermined alarm sound, and the like. .

  Next, transmission / reception processing of the inter-vehicle communication devices 1A, 1B will be described with reference to the flowcharts of FIGS. The transmission / reception processing routines shown in the flowcharts of FIGS. 11 and 12 are repeatedly executed at regular intervals by the electronic control device.

  First, the transmission / reception process of the vehicle requesting relay will be described with reference to the flowchart of FIG. Here, the vehicle A waiting for a right turn in the example shown in FIG. 4 is blocked by the presence of the vehicle C and cannot continuously receive the information of the vehicle B, and the vehicle existing around the vehicle B The case where C is used as a relay vehicle and the relay is requested will be described.

First, in step S01, the vehicle A receives information transmitted from another vehicle.
Next, the process proceeds to step S02, and vehicle A determines whether or not there is a short-time omission of information based on the reception history of information of other vehicles. In this embodiment, the short-time missing of information means a case where information is missing for a very short time. For example, if the vehicle is transmitting information every 100 msec, it is determined that a short-time omission of the vehicle information has occurred when the vehicle information received so far is not received within 100 msec. When the vehicle information is received within 100 msec, it is determined that there is no shortage of information.

If the determination result in step S02 is "YES" (information is missing for a short time), the process proceeds to step S03, and vehicle missing information (position information, etc.) with information missing for a short time is used as a reception history or the like. Based on the interpolation processing that is estimated based on this, the process proceeds to step S04.
On the other hand, if the determination result in step S02 is “NO” (no missing information for a short time), the process proceeds to step S04 without executing the interpolation process in S03.

  In step S04, the vehicle A executes a driving support determination process. For example, when the vehicle A is waiting for a right turn, it is determined whether or not there is a vehicle traveling straight on the oncoming lane.

  Next, the process proceeds to step S05, where the vehicle A determines whether or not there is information missing for a long time based on the reception history of information of other vehicles. In this embodiment, the long-term omission of information means a case where information on the same vehicle is not received continuously for a predetermined number of times (for example, 10 times) or more and information on the vehicle is lost. However, the predetermined number of times is not limited to 10 and can be set to an appropriate number.

  For example, in this embodiment, since a serial number is attached to the transmission data, if the serial number of the information of the vehicle B that has been directly transmitted from the vehicle B until now is continuously missing more than a predetermined value, the vehicle B It is determined that a long period of information has occurred. On the other hand, if the lack of the serial number of the information of the vehicle B that has been directly transmitted from the vehicle B so far is continuously less than the predetermined value, it is determined that there is no missing information for a long time.

  Alternatively, for example, when the vehicle transmits information every 100 msec (first predetermined time), for example, the received electric field strength of the radio wave transmitted from the vehicle B that has been received so far is below a certain level. When the state continues for the second predetermined time or longer, it is determined that the information of the vehicle B has been lost for a long time. On the other hand, if the received electric field strength of the radio wave transmitted from the vehicle B that has been reduced to a certain level or less is recovered before the second predetermined time has elapsed, it is determined that there is no long-term omission of vehicle information. To do. When the predetermined number of times is 10, the second predetermined time is 1 second.

If the determination result in step S05 is “YES” (the information is missing for a long time), the process proceeds to step S06, and the vehicle A is a specific vehicle based on the received information (position information) of the other vehicle. A vehicle that exists around the vehicle B and can communicate with the own vehicle (vehicle A) is searched. That is, a candidate for a relay vehicle is searched. In the example of the vehicles A, B, and C described above, the vehicle A lists the vehicle C as a relay vehicle candidate.
Next, the process proceeds from step S06 to step S07, a relay vehicle is set from the searched relay vehicle candidates, and the process proceeds to step S08. In the example of the vehicles A, B, and C described above, the vehicle A sets the vehicle C as a relay vehicle.

On the other hand, if the determination result in step S05 is “NO” (no missing information for a long time), the process proceeds to step S09 to determine whether or not information has been received from the vehicle that has lost information.
If the determination result in step S09 is “YES” (reception), the process proceeds to step S10, vehicle A cancels the setting (designation) of the relay vehicle, and the process proceeds to step S08.
If the determination result in step S09 is “NO” (not received), the process proceeds to step S08 without executing the process in step S10. That is, until the information is directly received from the specific vehicle (vehicle B) that has been missing for a long time, the relay vehicle setting is not canceled and the information on the vehicle A is transmitted via the relay vehicle (vehicle C). When the information is received directly from a specific vehicle (vehicle B) that has been missing information for a long time, the setting of the relay vehicle is canceled.

In step S08, the vehicle A collects vehicle information (for example, own vehicle position information) of the own vehicle necessary for the transmission information.
Next, it progresses to step S11, the own vehicle data corresponding to FIG. 6 is produced based on the information of the collected own vehicle, and also it progresses to step S12, and the produced own vehicle data is transmitted via the transmission means 12. It transmits to other vehicles, completes a series of processing, and returns.

  Next, the transmission / reception process of the vehicle requested to relay will be described with reference to the flowchart of FIG. Here, the case where the vehicle C in the example shown in FIG. 4 is requested to relay from the vehicle A will be described.

First, in step S21, the vehicle C receives the transmission data of the vehicle A.
Next, it progresses to step S22 and the vehicle C determines whether the own vehicle (vehicle C) is set (designated) as a relay vehicle based on the received transmission data of the vehicle A.
If the determination result in step S22 is “NO”, the vehicle C is not designated as a relay vehicle, so a series of processing is terminated and the process returns.

If the determination result in step S22 is “YES”, the vehicle C is designated as a relay vehicle from the vehicle A, so the process proceeds to step S23, where the vehicle C creates relay data corresponding to FIG. Proceeding to step S24, the vehicle C transmits the created relay data to the other vehicle via the transmission means 12, ends the series of processes, and returns.
Thereby, as shown in FIG. 12, the information of the vehicle A can be relayed to the vehicle C and transmitted to the vehicle B in which the information is missing for a long time.

  In the case where the vehicle B designated as the vehicle A does not receive the information related to the vehicle A directly transmitted from the vehicle A, but receives only the information related to the vehicle A transmitted via the vehicle C. The vehicle B sets the vehicle C as a relay vehicle, and transmits the own vehicle data of the vehicle B by the transmission means 12. Thus, the vehicle B can reliably transmit the information of the vehicle B to the vehicle A through the vehicle C.

  Further, the vehicle B designated as the vehicle A receives the information related to the vehicle A directly transmitted from the vehicle A and the information related to the vehicle A transmitted via the vehicle C, both of which are the same. In the case of information (information of the same serial number), the vehicle B transmits the own vehicle data of the vehicle B by the transmission unit 12 without setting the vehicle C as a relay vehicle. Thereby, the vehicle B can transmit the information of the vehicle B to the vehicle A quickly without relaying the vehicle C.

As described above, according to the inter-vehicle communication devices 1A and 1B in this embodiment, it is possible to detect the presence or absence of a vehicle (that is, a specific vehicle) for which information is not continuously received based on the actual communication state. And the vehicle can be specified.
A relay vehicle is specified only when there is a specific vehicle for which information is not continuously received, and information on the own vehicle is transmitted to the specific vehicle via this relay vehicle, and the information is not continuously received. When no vehicle is present, no relay vehicle is designated and communication via the relay vehicle is not performed, so that only minimal communication can be performed, and as a result, increase in communication traffic can be suppressed.

  Further, in this embodiment, when information on the same vehicle is not received continuously for a predetermined number of times (for example, 10 times) (specifically, when information on a specific vehicle is not received for a second predetermined time or more) (If the serial number of information from the vehicle is missing more than a predetermined value), it is defined as long-term information loss, and if there is a long-term information loss of a specific vehicle, a relay vehicle is set and relayed via the relay vehicle. Therefore, if the information omission of the specific vehicle is less than the predetermined number of times, it will not be omission for a long time. There is no communication through the vehicle. Thereby, the frequency of communication via a relay vehicle can be suppressed.

It is a functional block diagram in the Example of the inter-vehicle communication apparatus which concerns on this invention. It is a figure which shows an example of the own vehicle data transmitted / received in the inter-vehicle communication apparatus of an Example. It is a figure which shows an example of the relay data transmitted / received in the vehicle-to-vehicle communication apparatus of an Example. It is a figure which shows an example of the communication aspect of the right turn waiting vehicle in an intersection, and another vehicle in the inter-vehicle communication apparatus of an Example. It is a figure which shows an example of the time change of the received electric field strength in vehicle-to-vehicle communication. It is a figure which shows an example of the own vehicle data of the vehicle A in the communication aspect shown in FIG. It is a figure which shows an example of the own vehicle data of the vehicle B in the communication aspect shown in FIG. It is a figure which shows an example of the own vehicle data of the vehicle C in the communication aspect shown in FIG. It is a figure which shows an example of the relay data which the vehicle C relays in the communication aspect shown in FIG. It is a flowchart which shows the transmission / reception process of the vehicle by the side which requests relay in the inter-vehicle communication apparatus of an Example. It is a flowchart which shows the transmission / reception process of the vehicle by the side of which the relay is requested in the inter-vehicle communication apparatus of an Example. It is a figure which shows an example of the time chart of the information relay by a relay vehicle.

Explanation of symbols

1A, 1B Inter-Vehicle Communication Device 12 Transmitting means 13 Receiving means 14 Own vehicle communicable vehicle detecting means 15 Other vehicle communicable vehicle detecting means 18 Commutable vehicle information adding means 21 Relay means 22 Information discontinuity determining means

Claims (5)

Transmitting means for transmitting information to a vehicle outside the host vehicle;
Receiving means for receiving information from a vehicle outside the host vehicle;
Relay means for relaying information received by the receiving means to a vehicle outside the own vehicle by the transmitting means;
A vehicle-to-vehicle communication device comprising:
Vehicle detection means for detecting a vehicle communicable with the vehicle;
Information discontinuity determining means for determining whether information from the specific vehicle received by the receiving means is continuously received;
Communicable vehicle information adding means for adding vehicle information detected by the own vehicle communicable vehicle detecting means to information transmitted to the outside by the transmitting means;
Other vehicle communicable vehicle detection means for detecting a vehicle that exists around the specific vehicle and can communicate with the host vehicle,
When it is determined by the information discontinuity detection means that the information from the specific vehicle is not received continuously, the vehicle detected by the other vehicle communicable vehicle detection means is designated as a relay vehicle and the transmission means Send information,
The vehicle-to-vehicle communication apparatus according to claim 1, wherein the relay means relays when the own vehicle is instructed to relay information by the vehicle that has transmitted the information.   When the first vehicle is the host vehicle, the second vehicle is the specific vehicle, and the third vehicle is the relay vehicle, the second vehicle is transmitted from the received first vehicle. When the transmitted information and the information transmitted through the third vehicle are the same information, the information is transmitted by the transmission means without instructing the third vehicle as a relay vehicle. The inter-vehicle communication device according to claim 1.   When the first vehicle is the own vehicle, the second vehicle is the specific vehicle, and the third vehicle is the relay vehicle, the second vehicle is transmitted via the third vehicle. 3. The inter-vehicle communication device according to claim 1, wherein when only the information is received, the third vehicle is designated as a relay vehicle, and the information is transmitted by the transmission unit. The transmitting means transmits information every first predetermined time,
The information discontinuity determining means continuously receives information from the specific vehicle when the information from the specific vehicle received by the receiving means is not received for a second predetermined time longer than the first predetermined time. The inter-vehicle communication device according to any one of claims 1 to 3, wherein it is determined that the communication is not performed. The transmission means adds a serial number that is updated each time it is transmitted to the information and transmits it,
The information discontinuity determining means determines that information from the specific vehicle is not continuously received when a serial number of information from the specific vehicle received by the receiving means is missing a predetermined value or more. The inter-vehicle communication device according to any one of claims 1 to 4.

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