JP2004248084A - Inter-vehicle communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent communication errors when transferring information in direct communication between vehicles, resulting in transfer failure. <P>SOLUTION: An on-vehicle terminal device 10 mounted on each of the vehicles is provided with a radio communicating part 19, the opposite vehicle position detecting part 20 and a communicable time estimating part 21. The radio communicating part 19 determines information for communicating with the opposite vehicle party to communicate information. When communicating information, the communicable time estimating part 21 calculates a communicable time for being able to communicate with the opposite vehicle party on the basis of the position and vehicle speed of the opposite vehicle party acquired by the opposite vehicle position detecting part 20, and the radio communicating part 19 communicates and acquires only transferrable information within the calculated communication time. This can prevent the communication from stopping during information transfer, resulting in transfer failure. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an inter-vehicle communication device that performs direct communication between vehicles.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-183889 Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 2002-183889, there is a technique for exchanging information by performing direct communication between vehicles.
[0003]
[Problems to be solved by the invention]
However, according to the conventional technology, when direct communication is performed between vehicles while traveling, one of the vehicles moves ahead, or moves in a different direction at an intersection or the like, and the positional relationship between the two vehicles is not constant, so that the vehicle is not stable. It is difficult to maintain communication.
[0004]
In particular, when performing direct communication using narrow-area wireless communication between two vehicles without using a server or the like, instead of wide-area communication using a mobile phone, etc., a wireless LAN known as narrow-area wireless communication has an outlook of several hundreds. Although it has a communicable range of meters, communication cannot be maintained if the routes of both vehicles are different at an intersection or the like.
Further, even if the vehicle travels in the same direction, it is difficult to maintain communication if there is an obstacle between wireless communication and a host vehicle, such as a soundproof wall or a tunnel.
[0005]
As a result, the communication may be interrupted depending on the positional relationship between the two vehicles, and the data transfer may fail and the data transferred halfway may be wasted. This leads to a reduction in the use efficiency of communication resources, especially when a plurality of vehicles perform communication as a group, causing a problem that information exchange between vehicles is not effectively executed.
An object of the present invention is to provide an inter-vehicle communication device which can transfer information without interruption of communication and can efficiently use communication resources in view of the above conventional problems.
[0006]
[Means for Solving the Problems]
For this reason, the present invention has a communication means, a communicable time calculating means, and a communication information determining means. The possible time is calculated, and the communication information determining means determines information to communicate with the other vehicle based on the calculated communicable time.
[0007]
【The invention's effect】
According to the present invention, the communication possible time is calculated and estimated in advance, and the information to be communicated is determined based on the calculated communication possible time. There is no possibility that the data transferred up to that point is wasted, and the information can be transferred reliably. The effect of improving the use efficiency of communication resources is obtained.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the invention will be described with reference to examples.
FIG. 1 is a diagram illustrating a configuration of an in-vehicle terminal device mounted on a vehicle.
The in-vehicle terminal device 10 includes a destination input unit 16, road map data 15, a current position acquisition unit 14, a travel route calculation unit 13, a travel route storage unit 12, a traffic information acquisition unit 11, a display unit 17 , A selection unit 18, a wireless communication unit 19, a partner vehicle position detection unit 20, a communicable time estimation unit 21, and a control unit 22.
This in-vehicle terminal device 10 is attached to each vehicle.
[0009]
The wireless communication unit 19 communicates directly with another vehicle without using a server or the like using short-range wireless communication such as a wireless LAN having a communication distance of several hundred meters. In the present embodiment, the wireless communication unit 19 performs direct communication with another vehicle to exchange travel information between vehicles, for example, with a partner vehicle. The information to be exchanged includes, for example, vehicle speed, position information, and information on the current location and around the destination. It is also possible to acquire route information set as needed, turn signal information transmitted when turning right and left, and the like.
[0010]
The opponent vehicle position detection unit 20 acquires information such as the current position of the opponent vehicle and the vehicle speed related to the traveling of the vehicle from the opponent vehicle with which communication has been established, through the wireless communication unit 19.
The communicable time estimating unit 21 calculates and estimates the communicable time based on information such as the position of the partner vehicle and the vehicle speed.
The control unit 22 controls the entire device including communication with other vehicles.
[0011]
The destination input unit 16, the road map data 15, the current position acquisition unit 14, the travel route calculation unit 13, and the travel route storage unit 12 function as a car navigation system, and are input by the destination input unit 16. Based on the obtained destination and the current position of the own vehicle acquired by the current position acquisition unit 14, the traveling route calculation unit 13 calculates a traveling route to the destination using the road map data 15, and the calculated traveling route is calculated. The traveling route is stored in the traveling route storage unit 12.
[0012]
The travel route and the current position information calculated here or the travel information acquired from the partner vehicle by communication are displayed on the display unit 17. Which content is to be displayed can be selected by the selection unit 18.
The traffic information acquisition unit 11 includes, for example, a VICS beacon receiver and acquires the latest road information from outside the vehicle.
Next, direct communication between vehicles according to the present invention will be described. The setting of the travel route and the like are the same as those in the conventional car navigation system, and the description is omitted.
[0013]
FIG. 2 is a flowchart showing a communication flow.
In step 300, the wireless communication unit 19 issues a communication start request and inquires of vehicles around the own vehicle about communication start to search for a communicable vehicle.
In step 310, the wireless communication unit 19 checks whether a communication start response has been received in response to the communication start request. If there is a vehicle that has received a communication start request from the host vehicle and has returned a communication start response, the process proceeds to step 330 to establish a communication link with the partner vehicle that has issued the communication start response.
[0014]
If there is no communication start response in the check at step 310, the process proceeds to step 320 to check whether a communication start request from another vehicle has been received. If a communication start request has been received, a communication link is established with the partner vehicle that has transmitted the communication start request in step 330 as described above.
If there is no communication start response to the communication start request and there is no communication start request from another vehicle, the process returns to step 300 to repeatedly try starting communication with the surrounding vehicles.
[0015]
When a communication link is established and communication is started with a nearby vehicle in step 330, the process proceeds to step 340 to execute a communication start negotiation.
In the communication start negotiation, the wireless communication unit 19 determines traveling information to be exchanged with the other vehicle. At this time, the identification IDs of the own vehicle are transmitted to each other so that the other vehicle can be specified.
In step 350, it is determined whether to continue the communication. If there is information to be exchanged with the other vehicle by executing the communication start negotiation, it is necessary to perform communication for exchanging information, so the wireless communication unit 19 determines that communication is to be continued, and proceeds to step 360. If there is no information to be exchanged, it is determined that communication has been completed, and the process proceeds to step 395 to disconnect the communication link with the opponent vehicle.
[0016]
In step 360, the opponent vehicle position detection unit 20 acquires information such as the current position and the vehicle speed of the opponent vehicle from the opponent vehicle through the wireless communication unit 19. Since the data size of the current position and the vehicle speed information is small, the other vehicle is not separated during the transfer and the communication is not disconnected.
In step 370, the communicable time estimating unit 21 calculates and estimates the communicable time with the other vehicle using the information such as the current position and the vehicle speed of the other vehicle acquired by the other vehicle position detecting unit 20.
The calculation method will be described in detail based on various communication scenes described later.
[0017]
In step 380, the wireless communication unit 19 determines communication contents based on the communicable time estimated by the communicable time estimation unit 21, and communicates and acquires only information that can be transferred within the communicable time.
In step 385, the wireless communication unit 19 checks whether communication has been completed while monitoring whether communication with the opponent vehicle can be maintained. If the communication environment has deteriorated and communication cannot be maintained or communication has been completed, the process proceeds to step 395 to disconnect the communication link with the opponent vehicle. After disconnecting the communication link, the process returns to step 300 and attempts to start communication with another vehicle.
As described above, when there is traveling information to be transferred to the other vehicle in the communication start negotiation, the communicable time is calculated, and only the information that can be transferred within the communicable time is obtained by communication. Disconnection and transfer failure can be prevented, and communication resources can be used efficiently.
[0018]
Next, the calculation of the communicable time based on the communication scene will be described.
FIG. 3 is a communication scene for performing communication with a partner vehicle running in the same direction as the own vehicle.
In this communication scene, the traveling path 100 on which the host vehicle 1 and the opponent vehicle 2 are traveling intersects the right turn road 200 in front. The own vehicle 1 and the other vehicle 2 travel in the same lane, but the first travel lane 101 where the own vehicle travels is dedicated to straight ahead at the intersection with the right turn road 200, and the second travel lane where the other vehicle 2 travels At the intersection with the right turn road 200, both the straight running and the right turning are used.
[0019]
When the own vehicle 1 starts communicating with the opponent vehicle 2 traveling on the second traveling lane 102 while traveling on the first traveling lane 101, the opponent vehicle position detecting unit 20 detects the position based on the position information transmitted from the opponent vehicle. It is determined from the road map data 15 that the other vehicle is traveling on the second traveling lane 102. For the determination of the traveling lane, for example, the own vehicle 1 may be provided with a radar sensor, and may be determined based on the detection result of the radar sensor.
It is determined that the opponent vehicle 2 is traveling on the second traveling lane 102, and the place where the vehicle is currently traveling is a road without a branch, but at the next intersection, the first traveling lane 101 goes straight and the second traveling lane When it is determined that the lane 102 is going straight or a right turn lane, it can be determined that the own vehicle 1 goes straight at the next intersection, but the other vehicle 2 goes straight or turns right.
[0020]
Therefore, it is possible to reliably maintain a close distance to the opponent vehicle 2 from the current position to the intersection with the traveling road 200.
The communicable time estimating unit 21 acquires the current position of the opponent vehicle 2 and the position information of the next intersection from the road map data 15, calculates the distance between them, and calculates the calculated distance and the vehicle speed of the opponent vehicle 2. To calculate the travel time to the intersection. This running time is a communicable time during which communication can be reliably performed.
For example, when the opponent vehicle 2 is traveling at a speed of 40 km / h, the vehicle enters the intersection 250 meters away after 22.5 seconds, so that the communicable time is 22.5 seconds.
[0021]
The wireless communication unit 19 determines whether or not the travel information determined in the communication start negotiation can be transferred based on the calculated communicable time and the effective communication speed with the opponent vehicle 2.
For example, when the effective communication speed between both vehicles is 100 KBps, data transfer with a file size of 2.25 MBit is possible in 22.5 seconds.
[0022]
The wireless communication unit 19 determines whether or not the determined file size of the traveling information is a size that can be transferred within the communicable time. If the transfer is possible, the communication is continued and the determined traveling information is transferred. If transfer is not possible, for example, only some information is transferred according to the importance. If transfer of only some information is not possible, the communication link is disconnected and communication resources are allocated to other vehicles.
As described above, since the communicable time is calculated as the communicable time, it is possible to reliably transfer the determined traveling information without interruption of communication during traveling.
[0023]
When it is determined that the traveling information cannot be transferred, for example, it is possible to try to start communication with another vehicle, and when there is no other vehicle to communicate with, continue communication and transfer data. . Thereby, the utilization efficiency of the communication resources is further improved.
Also, in this case, during communication, the other vehicle position detecting unit 20 acquires the turn signal information from the other vehicle 2 through the wireless communication unit 19, and after receiving the turn signal information to turn right from the other vehicle 2 after traveling for a while, It is considered that the vehicle 2 almost certainly makes a right turn.
[0024]
Therefore, in this case, the wireless communication unit 19 controls communication with the opponent vehicle 2 and performs only communication that can be completed before the communication is disconnected. At this time, if it is determined that communication of the data being transferred is not completed before the vehicle enters the intersection, the communication link is disconnected without waiting for the vehicle to enter the intersection.
As a result, it is possible to transfer travel information with the other vehicle 2 with which the communication link has been established as much as possible without impairing the communication possibility with other vehicles, and it is possible to more efficiently use communication resources.
[0025]
Next, a modified example will be described.
The first modified example is a case where the traffic information acquisition unit 11 acquires traffic information from a VISC beacon. Here, it is assumed that the information that the right turn road 200 is temporarily blocked by, for example, road construction is obtained by the VISC beacon. At this time, since the opponent vehicle 2 cannot make a right turn to the right turn road 200, the communicable time estimation unit 21 does not extract the intersection information with the right turn road 200 from the road map data 15 for the right turn road 200, and Does not calculate the communicable time.
As a result, the calculation accuracy of the communicable time is improved, and traveling information of a larger file size can be transferred.
[0026]
The second modified example is a case where the other vehicle position detecting unit 20 acquires the traveling route information set in the traveling route storage unit 12 from the other vehicle 2. In this case, the communicable time estimation unit 21 illuminates the traveling direction of the opponent vehicle 2 and the traveling direction of the own vehicle 1 at the next intersection based on the traveling route information of the other vehicle and the traveling route information of the own vehicle. In addition, for example, if it is determined that the opponent vehicle 2 does not make a right turn on the right turn road 200, the calculation of the communicable time for the intersection with the right turn road 200 is not performed.
This can also improve the accuracy of calculating the communicable time, and can transfer data of a larger file size while preventing disconnection of communication.
[0027]
FIG. 4 shows a communication scene in a case where the own vehicle and the opponent vehicle are traveling in the oncoming lane.
In this case, a communication link cannot be established when the distance between the two vehicles is large, but a communication link can be established when the two vehicles enter a communicable area as the vehicle approaches. In addition, when the two vehicles pass each other and gradually separate from each other, communication cannot be maintained, and the communication link is disconnected.
[0028]
Here, it is assumed that the own vehicle 1 and the other vehicle 2 run on the same travel path 100, but the own vehicle 1 starts communication with the other vehicle 2 running on the down lane 202 while running on the up lane 201. The opponent vehicle position detection unit 20 acquires information such as the current position, the vehicle speed, and the traveling direction from the opponent vehicle 2, and the opponent vehicle 2 is traveling on the down lane 202 opposite to the host vehicle 1 based on the map road data 15. Detect that.
At this time, for example, assuming that the relative distance to the opponent vehicle 2 is 200 meters and the relative vehicle speed is 80 km / h, it takes 9 seconds for the own vehicle 1 to move to the position of the opponent vehicle 2 at the time of starting the communication. Take it. This time is a communicable time during which communication can be reliably performed.
[0029]
Accordingly, the communicable time estimation unit 21 calculates the distance between the host vehicle 1 and the opponent vehicle 2 when the communication is started, and calculates the relative distance between the opponent vehicle and the host vehicle based on the calculated distance and the relative speeds of the two vehicles. The amount of time change of the position is estimated, and the time to the position of the opponent vehicle 2 at the start of communication is calculated. Since this time is a communicable time, for example, when it is calculated as 9 seconds, when the effective communication speed between vehicles is 100 KBps, data transfer of a 900 KBit file size is possible.
[0030]
The wireless communication unit 19 performs communication of transferable travel information within the calculated communicable time to acquire travel information.
As a result, traveling information can be reliably exchanged between vehicles traveling on opposite lanes.
[0031]
FIG. 5 shows a communication scene in a case where the own vehicle and the other vehicle are traveling in the oncoming lane as in FIG.
Unlike FIG. 4 in which there is no intersection between the host vehicle 1 and the opponent vehicle 2 after the communication is started, in FIG. 5, there is an intersection 300 that intersects with the travel path 100 on which both vehicles travel, and therefore, both vehicles May change course in the same direction. If the course is changed in the same direction, communication can be continued even after passing through the intersection.
[0032]
Next, the calculation of the communicable time in this case will be described.
When the own vehicle 1 and the opponent vehicle 2 start communication with each other across the intersection 300, the opponent vehicle position detection unit 20 determines that the opponent vehicle 2 is moving down the lane based on the current position, vehicle speed, and traveling direction acquired from the opponent vehicle 2. It is detected that the vehicle is traveling in 202. Further, based on information from the host vehicle 1, the host vehicle 1 detects that the host vehicle 1 is traveling on the up lane 201.
[0033]
Further, if it is determined from the turn signal information of each vehicle that both the own vehicle 1 and the opponent vehicle 2 have changed courses in the same traveling direction, the vehicles will travel in the same direction after passing through the intersection, so that communication may be continued. 4, the vehicle 1 does not calculate the time required to reach the position of the opponent vehicle 2 at the start of communication, as shown in FIG. 4, but may travel in a different direction after passing through an intersection. The communication time is calculated by calculating the travel time to the next intersection on the travel road 300 having the road.
Note that the change of the course may be determined not by the turn signal information but by, for example, the traveling direction instructed by the traveling path that the own vehicle 1 is traveling on the lane dedicated to left turn and the opponent vehicle 2 is traveling on the lane dedicated to right turn. .
[0034]
FIG. 6 shows a scene in which the own vehicle and the opponent vehicle run in the same direction, but a communication-disabled area exists ahead.
Here, the own vehicle 1 and the opponent vehicle 2 travel in the same direction, but after traveling for a while, approach the tunnel 500. If the vehicle is traveling in the same lane, communication can be performed inside the tunnel. However, since the tunnel 500 on this road is provided for each of the lanes 301 and 302, while traveling in the tunnel 500, Communication is expected to be disconnected. However, after passing through the tunnel 500, there is a possibility that communication with the other vehicle can be restarted.
Therefore, if the estimated time to pass through the tunnel 500 is calculated and the communication session is maintained during the passage, communication can be resumed after passing through the tunnel.
[0035]
Next, maintenance of a communication session will be described.
Since the own vehicle 1 and the other vehicle 2 are traveling in the same direction, after the own vehicle 1 and the other vehicle 2 start communication, the communicable time estimation unit 21 The communicable time is calculated from the current position, the vehicle speed, and the traveling direction acquired from the vehicle 2. The wireless communication unit 19 performs communication of transferable travel information within a communicable time.
[0036]
However, here, the tunnel 500 exists in front, and the tunnel 500 is provided for each lane. Therefore, if the vehicle is traveling on a different lane, the communication is disconnected. In such a case, the communicable time estimating unit 21 calculates an estimated time to pass through the tunnel 500 from the road map data 15 based on the length of the tunnel 500 and the vehicle speed information.
[0037]
FIG. 7 is a flowchart for calculating the expected time.
In step 400, the communicable time estimating unit 21 uses the road map data 15 to disconnect communication with the opponent vehicle 2 ahead of the travel road based on the positions of the own vehicle 1 and the opponent vehicle 2 based on the positions of the own vehicle 1 and opponent vehicle 2 In the embodiment, the tunnel 500) is detected.
In step 410, as a result of the search using the road map data 15, it is determined whether or not it is possible to restart the communication session with the opponent vehicle 2 after passing through the communication impossible area. If the communication session cannot be restarted, in step 420, the distance from the current position to the communication disabled area is calculated, and the communication available time to the communication disabled area is calculated. For example, the calculation is performed for the next intersection as shown in FIG. Correct the available communication time.
[0038]
If it is determined in step 410 that the communication session can be resumed, in step 430, the length of the incommunicable area, for example, the length of the tunnel 500 is obtained from the road map data 15 to obtain the current vehicle speed and traffic information obtaining unit 11 Calculate the expected hold time for maintaining the communication session, taking into account the traffic conditions acquired in the above. The expected hold time can be calculated, for example, by adding a margin as a fluctuation of the expected time to the transit time expected from the current vehicle speed.
[0039]
FIG. 8 is a flowchart showing the flow of the operation after entering the communication disabled area.
When the own vehicle 1 or the opponent vehicle 2 enters, for example, the tunnel 500 and the communication between the two vehicles is cut off, in step 500, the communicable time estimation unit 21 sets the calculated expected holding time timer.
After determining in step 510 whether the expected hold time timer has timed out, in step 520, a re-communication request is transmitted to the opponent vehicle 2.
[0040]
If it is determined in step 530 that there is a response from the opponent vehicle 2, for example, the vehicle has exited the tunnel 500, and the communication link is reestablished in step 550. Even if there is no response from the other vehicle 2 to the re-communication request transmitted by the own vehicle 1, if it is determined in step 540 that there is a re-communication request from the other vehicle 2, the communication link is similarly re-established in step 550. . When the communication link is re-established, the communication is continued and the transfer of the remaining driving information is restarted.
[0041]
If there is no response from the opponent vehicle 2 to the recommunication request transmitted by the host vehicle 1 and there is no recommunication request from the opponent vehicle, the retransmission request is transmitted and the The check for retransmission request is repeated. If it is determined in step 510 that the expected hold time timer has timed out, the communication session is discarded in step 560, and the process ends.
[0042]
That is, when communication is performed between the own vehicle 1 traveling in the lane 301 and the other vehicle 2 traveling in the lane 302 different from the own vehicle in the same traveling direction, there is a tunnel 500 incapable of communication in front of the lane. If it turns out, if the vehicle enters the tunnel as it is, the communication with the opponent vehicle 2 is cut off. However, according to the road map data 15, the tunnel 500 from which communication can be resumed after passing is, for example, 1 km long. When passing through a tunnel having a length of 1 km at a speed of 60 km / h, it takes 60 seconds. Assuming that a margin of 20% is taken as fluctuation of the expected time, a 72-second expected hold time timer is set in consideration of a 12-second margin.
[0043]
After entering the tunnel 500 and the communication with the opponent vehicle 2 is cut off, the expected hold time timer starts operating. Until the expected hold time timer times out, a re-communication request is transmitted to the opponent vehicle 2. If there is no response from the opponent vehicle and there is no re-communication request from the opponent vehicle, re-communication with the opponent vehicle 2 is repeated within the time of the expected hold time timer.
[0044]
As a result, after the communication is temporarily disconnected due to a tunnel or the like, the communication can be performed again, and a large amount of data can be transferred.
When the communication session cannot be resumed by setting the holding time of the communication session within the expected holding time, the communication resource can be switched to another vehicle, and the utilization efficiency of the communication resource is improved.
[0045]
In this embodiment, step 300, step 310, step 320, step 330, step 340, step 350, step 385, and step 395 constitute a communication unit.
Step 370 constitutes the communicable time calculation means.
Step 380 constitutes the communication information determining means.
Step 400, step 410, and step 430 constitute the communication suspension time calculation means.
Step 500, step 510, step 520, step 530, step 540, step 550, and step 560 constitute a communication session maintaining means.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an in-vehicle terminal device mounted on a vehicle.
FIG. 2 is a flowchart showing a communication flow.
FIG. 3 is a communication scene for performing communication with a partner vehicle running in the same direction as the host vehicle.
FIG. 4 is a communication scene in a case where a host vehicle and a partner vehicle are traveling in an oncoming lane.
FIG. 5 is a communication scene in a case where a host vehicle and a partner vehicle are traveling in an oncoming lane.
FIG. 6 shows a scene in which the own vehicle and the opponent vehicle run in the same direction, but a communication-disabled area exists ahead.
FIG. 7 is a flowchart for calculating an expected time.
FIG. 8 is a flowchart showing a flow of an operation after entering a communication disabled area.
[Explanation of symbols]
1 own vehicle 2 other vehicle 11 traffic information acquisition unit (traffic information acquisition means)
12 travel route storage unit 13 travel route calculation unit 14 current position acquisition unit 15 road map data 16 destination input unit 17 display unit 18 selection unit 19 wireless communication unit 20 partner vehicle position detection unit 21 communicable time estimation unit 22 control unit 100 , 300 traveling road 101 first traveling lane 102 second traveling lane 201 up lane 202 down lane 301, 302 lane 500 tunnel

Claims (10)

In a vehicle-to-vehicle communication device provided in a plurality of vehicles and performing direct communication between vehicles,
A communication means for establishing communication with another vehicle and performing communication,
Communication available time calculating means for calculating a communication available time during which communication can be established with the opponent vehicle,
A communication information determining means for determining information to be communicated with the opponent vehicle based on the calculated communicable time. The vehicle-to-vehicle communication device according to claim 1, wherein the communicable time calculation means acquires the communicable time calculation information from the partner vehicle and calculates the communicable time. The communicable time calculating means estimates the time change amount of the relative position between the other vehicle and the own vehicle based on the vehicle speed information of the other vehicle and the vehicle speed of the own vehicle acquired from the other vehicle, and calculates the communicable time 3. The vehicle-to-vehicle communication device according to claim 1, wherein 4. The communication time according to claim 1, wherein the communication time calculation means calculates the communication time using information on a traveling direction set in a traveling lane in which the other vehicle travels. The inter-vehicle communication device according to claim 1. 5. The communication available time calculation means calculates the communication available time based on the traveling direction of the own vehicle using information on the traveling direction of the other vehicle acquired from the other vehicle. 6. The inter-vehicle communication device according to any one of the above. The vehicle-to-vehicle communication apparatus according to claim 5, wherein the information on the traveling direction of the opponent vehicle and the traveling direction information of the own vehicle are obtained from route information registered in a navigation system of each vehicle. The vehicle-to-vehicle communication apparatus according to claim 5, wherein the information on the traveling direction of the opponent vehicle and the traveling direction information of the own vehicle are turn signal information transmitted when each vehicle turns right or left. The traffic information acquisition means for acquiring traffic information from the outside is provided, and the communicable time calculation means calculates the communicable time using the traffic information acquired from the outside. 7. The inter-vehicle communication device according to any one of 7. Communication stop time calculation means for calculating the communication stop time is provided, and the communication stop time calculation means determines the communication stop time when it is determined that the communication may be resumed after a temporary communication disconnection. The vehicle-to-vehicle communication device according to any one of claims 1 to 8, wherein the inter-vehicle communication device calculates an expected holding time until the communication can be restarted. 10. The inter-vehicle communication apparatus according to claim 9, further comprising a communication session maintaining unit, wherein the communication session maintaining unit maintains the communication session within the calculated expected suspension time after the temporary communication disconnection. .

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