JP6323342B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus that is mounted on a vehicle and performs wireless communication with another vehicle.

  As one of intelligent road traffic systems, an inter-vehicle communication system for the purpose of safe driving support is known. In this inter-vehicle communication system, an in-vehicle device mounted on a vehicle transmits / receives position information and state information (such as speed and vehicle azimuth angle) of the host vehicle to / from an on-vehicle device mounted on another vehicle. The in-vehicle device determines the risk of a collision accident based on the received information and the position information and status information of the host vehicle, and alerts the driver to prevent the collision accident. To do.

  In Japan, the frequency band for this inter-vehicle communication system is assigned to the 700 MHz band. Similar communication systems are also being studied in the United States and Europe, and the frequency band for this inter-vehicle communication system is assigned to the 5.8 GHz band.

With the spread of this system in the future, the realization of a safer transportation society is expected.
In the inter-vehicle communication system, the base station does not perform communication management and control, but each in-vehicle device performs communication control in an autonomous and distributed manner. The access control method employs the CSMA method, and each in-vehicle device periodically performs broadcast transmission according to this method. Inter-vehicle communication basically performs transmission and reception by time division multiplexing using a preset frequency channel. For this reason, in a place where a large number of vehicles are concentrated, communication traffic becomes high and communication packets may collide. If the packet arrival rate decreases due to a collision of communication packets, the operation of the safe driving support application may be hindered.

  As a method for overcoming this problem, there is known a method of performing communication at a transmission frequency set in advance according to the traveling direction of the own vehicle when the own vehicle reaches a frequency control region of a certain distance or less from the intersection. (For example, refer to Patent Document 1).

Japanese Patent No. 5266469

  However, in the technique described in Patent Document 1, when the number of vehicles traveling on the same road in the same traveling direction increases, the number of vehicles assigned to the same transmission frequency increases, and communication traffic is concentrated. there were.

  The present invention has been made in view of these problems, and an object thereof is to suppress concentration of communication traffic at a specific transmission frequency.

  The present invention made to achieve the above object is a wireless communication device mounted on a vehicle, wherein the first wireless communication means, the second wireless communication means, the message creation means, the own vehicle transmission judgment means, Other vehicle transmission determination means, transmission selection means, and addition means.

  The first wireless communication means transmits and receives data wirelessly using a preset first frequency band. The second wireless communication means transmits and receives data wirelessly using a second frequency band set in advance so as to be different from the first frequency band.

The message creation means obtains at least own vehicle information indicating the current position of the vehicle and the state of the vehicle, and creates a message.
The own vehicle transmission determining means determines whether or not to transmit the own vehicle transmission message, which is a message created by the message creating means, to the first wireless communication means.

  The other vehicle transmission determination means includes first frequency band request instruction information indicating whether or not data transmission in the first frequency band is requested in another vehicle reception message that is a message received from another vehicle different from the vehicle. Based on whether or not it is included, it is determined whether or not to transmit the own vehicle transmission message to the first wireless communication means.

  The transmission selection unit causes the host vehicle transmission message to be transmitted to at least one of the first radio communication unit and the second radio communication unit based on the determination result by the host vehicle transmission determination unit and the other vehicle transmission determination unit.

The adding means adds the first frequency band request instruction information to the own vehicle transmission message based on the determination result by the own vehicle transmission determining means.
The wireless communication apparatus of the present invention configured as described above first includes a first wireless communication unit that performs data communication using the first frequency band and a second wireless communication unit that performs data communication using the second frequency band. At least one of them transmits the own vehicle transmission message. For this reason, when a plurality of vehicles equipped with the wireless communication device of the present invention perform inter-vehicle communication, it is possible to suppress the concentration of communication traffic in either the first frequency band or the second frequency band. .

  In addition, the wireless communication device of the present invention determines whether or not to transmit the own vehicle transmission message to the first wireless communication means. For this reason, the wireless communication apparatus of the present invention performs data in a frequency band other than the first frequency band when it is determined that the transmission of the own vehicle transmission message by the first wireless communication means is unnecessary. Can do. For this reason, when a plurality of vehicles equipped with the wireless communication device of the present invention perform inter-vehicle communication, an increase in the number of vehicles that perform data transmission in the first frequency band can be suppressed. Communication traffic concentration can be suppressed.

  The wireless communication device of the present invention is based on whether or not the other vehicle reception message includes first frequency band request instruction information indicating whether or not data transmission in the first frequency band is requested. Then, it is determined whether or not to transmit the own vehicle transmission message to the first wireless communication means. For this reason, the wireless communication device of the present invention is based on the first frequency band request instruction information, and determines that the other vehicle is requesting data transmission in the first frequency band from the own vehicle. The own vehicle transmission message can be transmitted using one frequency band.

  And the radio | wireless communication apparatus of this invention adds the 1st frequency band request | requirement instruction information to the said own vehicle transmission message based on the determination result by the own vehicle transmission determination means. Therefore, when a plurality of vehicles equipped with the wireless communication device of the present invention perform inter-vehicle communication, the wireless communication device of the present invention is a case where the other vehicle reception message is received from the other vehicle in the first frequency band. However, based on whether or not the other vehicle reception message includes the first frequency band request instruction information, whether or not the transmission source of the received other vehicle reception message requests transmission in the first frequency band. Can be judged. Then, the wireless communication device of the present invention does not transmit the own vehicle transmission message using the first frequency band when it is determined that the transmission source does not request transmission in the first frequency band. Can be. In other words, the wireless communication apparatus of the present invention can request transmission of a message using the first frequency band, limited to the range where the own vehicle transmission message reaches from the own vehicle.

  As a result, the wireless communication device of the present invention limits the number of wireless communication devices that transmit messages using the first frequency band in response to a request from the host vehicle to the range that the message transmitted by the host vehicle reaches. And concentration of communication traffic in the first frequency band can be suppressed.

1 is a block diagram illustrating a configuration of an in-vehicle device 1. FIG. It is a flowchart which shows the self-device transmission request process of 1st Embodiment. It is a flowchart which shows the other apparatus transmission request process of 1st Embodiment. It is a flowchart which shows the transmission method determination process of 1st Embodiment. It is a flowchart which shows the transmission message construction process of 1st Embodiment. It is a flowchart which shows the transmission method selection process of 1st Embodiment. It is a flowchart which shows the band state determination process of 1st Embodiment. It is a top view of road R1, R2 explaining the 1st specific example of operation | movement of the vehicle-mounted apparatus 1 in 1st, 4 embodiment. It is a top view of road R1, R2 explaining the 2nd specific example of operation | movement of the vehicle-mounted apparatus 1 in 1st Embodiment. It is a flowchart which shows the other apparatus transmission request process of 2nd Embodiment. It is a flowchart which shows the transmission method selection process of 2nd Embodiment. It is a top view of road R1, R2 explaining the specific example of operation | movement of the vehicle-mounted apparatus 1 in 2nd Embodiment. It is a flowchart which shows the transmission method selection process of 3rd Embodiment. It is a top view of road R3, R4 explaining the specific example of operation | movement of the vehicle-mounted apparatus 1 in 3rd Embodiment. It is a flowchart which shows the transmission message construction process of 4th Embodiment. It is a flowchart which shows the other apparatus transmission request process of 4th Embodiment. It is a top view of road R5 explaining the specific example of operation | movement of the vehicle-mounted apparatus 1 in 4th Embodiment.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
The in-vehicle device 1 of the present embodiment is mounted on a vehicle and includes a first band communication unit 11, a second band communication unit 12, an application unit 13, and a facilitation unit 14, as shown in FIG.

  The first band communication unit 11 includes a transmission unit 21 and a reception unit 22. The transmission unit 21 wirelessly transmits data to other vehicles existing around the host vehicle using a preset first frequency band (700 MHz band in the present embodiment). The receiving unit 22 wirelessly receives data from other vehicles existing around the host vehicle using the first frequency band.

  The second band communication unit 12 includes a transmission unit 31 and a reception unit 32. The transmission unit 31 wirelessly transmits data to other vehicles existing around the host vehicle using a preset second frequency band (5.8 GHz band in the present embodiment). The receiving unit 32 wirelessly receives data from other vehicles existing around the host vehicle using the second frequency band.

  The application unit 13 is a functional block realized by software processing executed by the microcomputer. In the present embodiment, for example, processing for realizing a service for the purpose of avoiding a collision with another vehicle is executed. To do.

  The application unit 13 acquires a detection signal from the sensor group 2 including a plurality of sensors mounted on the vehicle, and acquires road map data from the map database 3 that stores road map data.

  And the application part 13 uses the information which other vehicles use for performing services, such as collision avoidance with the own vehicle, based on the detection signal acquired from the sensor group 2, and the road map data acquired from the map database 3. Generate and output transmission data including it. The application unit 13 can specify at least the current position of the host vehicle, the traveling speed of the host vehicle, and the traveling direction of the host vehicle based on the detection signal acquired from the sensor group 2.

Further, the application unit 13 outputs transmission request information for requesting wireless transmission of the generated transmission data together with the generated transmission data.
The application unit 13 also determines the possibility that the host vehicle will collide with the other vehicle based on the detection signal acquired from the sensor group 2, the road map data acquired from the map database 3, and the received data received from the other vehicle. Judgment is made, and a warning sound or an image display is output if necessary.

The facilitation unit 14 is a functional block realized by software processing executed by the microcomputer.
The facilitation unit 14 includes a transmission message construction unit 41, a transmission method selection unit 42, a reception message decomposition unit 43, a band state determination unit 44, and a transmission method determination unit 45.

  The transmission message construction unit 41 constructs and outputs a transmission message based on the detection signal acquired from the sensor group 2, the road map data acquired from the map database 3, and the transmission data acquired from the application unit 13. The transmission message includes at least vehicle position information and vehicle state information. The vehicle position information indicates the current position of the host vehicle. The vehicle state information indicates the traveling speed and traveling direction of the host vehicle.

The transmission method selection unit 42 selects a communication unit that transmits a transmission message from the first band communication unit 11 and the second band communication unit 12.
The received message disassembling unit 43 uses the data received by the first band communication unit 11 or the second band communication unit 12 for data used by the application unit 13 for avoiding a collision with another vehicle (hereinafter referred to as application use data) And the application usage data is output to the application unit 13.

  The received message decomposition unit 43 extracts data used by the transmission method determination unit 45 (hereinafter referred to as transmission method determination data) from the received message and outputs the transmission method determination data to the transmission method determination unit 45. The transmission method determination data includes at least vehicle position information and vehicle state information. Furthermore, when there is a request for data transmission using the first frequency band (hereinafter referred to as a first band transmission request), the transmission method determination data further includes first band transmission request information.

The band state determination unit 44 determines the degree of congestion in the first frequency band.
The transmission method determination unit 45 includes an own device transmission request determination unit 51, another device transmission request determination unit 52, and a transmission method determination unit 53.

The own device transmission request determination unit 51 determines whether or not the in-vehicle device 1 of the own vehicle requests data transmission in the first frequency band.
The other device transmission request determination unit 52 determines whether or not the in-vehicle device 1 of the other vehicle requests data transmission in the first frequency band.

The transmission method determination unit 53 determines the frequency band used for transmission based on the determination results of the own device transmission request determination unit 51 and the other device transmission request determination unit 52.
Next, software processing (hereinafter referred to as “own device transmission request processing”) executed by the microcomputer in order to realize the function of the own device transmission request determination unit 51 will be described. The own apparatus transmission request process is a process repeatedly executed during the operation of the in-vehicle apparatus 1.

  When the own device transmission request process is executed, the microcomputer of the in-vehicle device 1 first determines whether or not transmission request information is input from the transmission message construction unit 41 in S10 as shown in FIG. Here, when the transmission request information is not input (S10: NO), the own apparatus transmission request process is once ended. On the other hand, when the transmission request information is input (S10: YES), the host vehicle crosses the intersection based on the detection signal acquired from the sensor group 2 and the road map data acquired from the map database 3 in S20. Alternatively, it is determined whether or not the vehicle is about to enter the junction.

  In S30, based on the determination result in S20, it is determined whether or not the host vehicle is about to enter an intersection or a junction. If the host vehicle is about to enter an intersection or junction (S30: YES), the first band transmission request flag is set in S40, and the process proceeds to S60.

On the other hand, if the host vehicle is not about to enter the intersection or junction (S40: NO), the first band transmission request flag is cleared in S50, and the process proceeds to S60.
When the process proceeds to S60, transmission request related information indicating whether or not the first band transmission request flag is set is generated and output, and the own apparatus transmission request process is temporarily ended.

  Next, software processing (hereinafter referred to as other device transmission request processing) executed by the microcomputer in order to realize the function of the other device transmission request determination unit 52 will be described. The other apparatus transmission request process is a process repeatedly executed during the operation of the in-vehicle apparatus 1.

  When the other apparatus transmission request process is executed, the microcomputer of the in-vehicle apparatus 1 first determines whether or not transmission method determination data is input from the received message decomposition unit 43 in S110 as shown in FIG. . Here, when the transmission method determination data is not input (S110: NO), the other apparatus transmission request process is temporarily ended.

On the other hand, if transmission method determination data is input (S110: YES), it is determined in S120 whether or not the first band transmission request information is included in the transmission method determination data.
Here, if the first band transmission request information is not included (S120: NO), the first band transmission flag is cleared in S130, and the other apparatus transmission request process is temporarily ended.

  On the other hand, when the first band transmission request information is included (S120: YES), the vehicle position information and vehicle state information (that is, the position of the other vehicle and the other vehicle) included in the transmission method determination data in S140. Information indicating a state), a detection signal acquired from the sensor group 2 (that is, information indicating the position and state of the host vehicle), information acquired from the map database 3 (that is, information indicating a surrounding situation of the host vehicle), and Based on this, the possibility that the own vehicle and the other vehicle cross each other is determined.

  Then, in S150, based on the determination result in S140, it is determined whether or not there is a possibility that the own vehicle and the other vehicle are mixed. If there is a possibility that the host vehicle and the other vehicle are mixed (S150: YES), the first band transmission flag is set in S160, and the other device transmission request process is temporarily terminated.

On the other hand, when there is no possibility that the own vehicle and the other vehicle cross (S150: NO), the first band transmission flag is cleared in S170, and the other device transmission request process is once ended.
Next, software processing (hereinafter referred to as transmission method determination processing) executed by the microcomputer in order to realize the function of the transmission method determination unit 53 will be described.

The transmission method determination process is a process that is repeatedly executed during the operation of the in-vehicle device 1.
When the transmission method determination process is executed, the microcomputer of the in-vehicle device 1 first determines whether or not the first band transmission request flag is set in S310 as shown in FIG. If the first band transmission request flag is set (S310: YES), the process proceeds to S330.

  On the other hand, if the first band transmission request flag is cleared (S310: NO), it is determined in S320 whether the first band transmission flag is set. If the first band transmission flag is cleared (S320: NO), the process proceeds to S410. On the other hand, when the 1st band transmission flag is set (S320: YES), it shifts to S330.

  When the process proceeds to S330, the degree of congestion of the first frequency band is determined based on the latest band state information input from the band state determination unit 44. Specifically, when the degree of congestion indicated by the band state information is 0, 1, 2, 3, it is determined that the degree of congestion in the first frequency band is 0, 1, 2, 3, respectively.

  Next, in S340, based on the determination result in S330, it is determined whether or not the congestion degree of the first frequency band is zero. If the congestion degree of the first frequency band is 0 (S340: YES), the value indicated by the first transmission cycle information is set to 0 in S350, and the process proceeds to S410.

  On the other hand, when the congestion degree of the first frequency band is not 0 (S340: NO), it is determined whether or not the congestion degree of the first frequency band is 1 in S360. If the congestion degree of the first frequency band is 1 (S360: YES), the value indicated by the first transmission cycle information is set to 1 in S370, and the process proceeds to S410.

  On the other hand, when the degree of congestion in the first frequency band is not 1 (S360: NO), it is determined in S380 whether the degree of congestion in the first frequency band is 2. Here, when the congestion degree of the first frequency band is 2 (S380: YES), the value indicated by the first transmission cycle information is set to 2 in S390, and the process proceeds to S410.

  On the other hand, if the congestion degree of the first frequency band is not 2 (S380: NO), it is determined that the congestion degree of the first frequency band is 3, and the first band transmission flag and the first band are determined in S400. The transmission request flag is cleared, and the process proceeds to S410.

  In S410, transmission method instruction information is generated and output to the transmission method selection unit 42. The transmission method instruction information includes a first band transmission flag, a first band transmission request flag, and first transmission cycle information.

  Next, software processing (hereinafter referred to as transmission message construction processing) executed by the microcomputer in order to realize the function of the transmission message construction unit 41 will be described. The transmission message construction process is a process that is repeatedly executed during the operation of the in-vehicle device 1.

  When the transmission message construction process is executed, the microcomputer of the in-vehicle device 1 first determines whether or not transmission data and transmission request information are input from the application unit 13 in S510, as shown in FIG. Here, when transmission data and transmission request information are not input (S510: NO), the transmission message construction process is temporarily ended.

On the other hand, when transmission data and transmission request information are input (S510: YES), transmission request information is output to the transmission method determination unit 45 in S520.
Thereafter, in S530, it is determined whether transmission request related information is input from transmission method determination unit 45 or not. If the transmission request related information is not input (S530: NO), the process of S530 is repeated until the transmission request related information is input. On the other hand, when the transmission request related information is input (S530: YES), the detection signal acquired from the sensor group 2, the road map data acquired from the map database 3, and the application unit 13 are acquired in S540. A transmission message is constructed based on the transmission data.

  Then, in S550, it is determined whether or not the first band transmission request flag is set. Here, if the first band transmission request flag is set (S550: YES), the first band transmission request information indicating that there is a first band transmission request in S560 is the transmission constructed in S540. This transmission message is included in the message and output to the transmission method selection unit 42. Then, when the output of the transmission message is completed, the transmission message construction process is once ended.

  On the other hand, if the first band transmission request flag is not set (S550: NO), the transmission message constructed in S540 is output to the transmission method selection unit 42 in S570, and the transmission message construction process is temporarily terminated. To do.

  Next, software processing (hereinafter referred to as transmission method selection processing) executed by the microcomputer in order to realize the function of the transmission method selection unit 42 will be described. The transmission method selection process is a process that is repeatedly executed during the operation of the in-vehicle device 1.

  When the transmission method selection process is executed, the microcomputer of the in-vehicle device 1 first determines whether or not a transmission message is input from the transmission message construction unit 41 in S610 as shown in FIG. If no transmission message has been input (S610: NO), the transmission method selection process is temporarily terminated. On the other hand, when a transmission message is input (S610: YES), in S620, the first band transmission flag or the first band transmission request flag included in the transmission method instruction information input from the transmission method determination unit 53 is displayed. It is determined whether it is set. Here, when the first band transmission flag or the first band transmission request flag is set (S620: YES), in S630, the input transmission message is output to the first band communication unit 11, The transmission method selection process is temporarily terminated.

  On the other hand, when the first band transmission flag and the first band transmission request flag are cleared (S620: NO), the input transmission message is output to the second band communication unit 12 and transmitted in S640. The method selection process is temporarily terminated.

  Next, software processing (hereinafter referred to as band state determination processing) executed by the microcomputer to realize the function of the band state determination unit 44 will be described. The band state determination process is a process that is repeatedly executed during the operation of the in-vehicle device 1.

  When the band state determination process is executed, as shown in FIG. 7, the microcomputer of the in-vehicle device 1 first loads the band load of the first frequency band from the receiving unit 22 of the first band communication unit 11 in S710. The indicated band load information is acquired.

  Thereafter, in S720, it is determined whether or not the band load indicated by the band load information is greater than a preset first threshold value. If the band load is greater than the first threshold (S720: YES), the congestion degree of the first frequency band is set to 3 in S730, and the process proceeds to S790.

  On the other hand, if the band load is equal to or less than the first threshold (S720: NO), is the band load indicated by the band load information greater than the second threshold set to be smaller than the first threshold in S740? Judge whether or not. If the band load is greater than the second threshold (S740: YES), the congestion degree of the first frequency band is set to 2 in S750, and the process proceeds to S790.

  On the other hand, if the band load is equal to or lower than the second threshold (S740: NO), is the band load indicated by the band load information greater than the third threshold set to be smaller than the second threshold in S750? Judge whether or not. If the band load is greater than the third threshold (S760: YES), the congestion degree of the first frequency band is set to 1 in S770, and the process proceeds to S790.

On the other hand, if the band load is equal to or smaller than the third threshold (S760: NO), the congestion degree of the first frequency band is set to 0 in S770, and the process proceeds to S790.
Then, when the process proceeds to S790, band state information indicating the degree of congestion set in S730, S750, S770, and S780 is output to the transmission method determination unit 45, and the band state determination process is temporarily ended.

Next, a specific example of the operation of the in-vehicle device 1 configured as described above will be described.
For example, as shown in FIG. 8A, the road R1 and the road R2 intersect at a junction J1, the vehicle V1 travels on the road R1 toward the junction J1, and the vehicles V2 and V3 meet. It is assumed that the vehicle is traveling on the road R2 toward J1. It is assumed that the road R2 is a priority road with respect to the road R1. Further, it is assumed that the vehicle V2 is traveling on the road R2 ahead of the vehicle V3. At this time, the vehicles V1, V2, and V3 are transmitting messages in the second frequency band (5.8 GHz band in the present embodiment).

  Then, as shown in FIG. 8B, when the vehicle V1 on the road R1 approaches the junction J1, a message including the first band transmission request information is sent to the first frequency band (700 MHz band in the present embodiment). Send with.

  Further, when the vehicle V2 on the road R2 approaches the junction J1, the message from the vehicle V1 is received in the first frequency band. Since this message includes the first band transmission request information, the vehicle V2 transmits the message in the first frequency band. However, the message transmitted by the vehicle V2 in the first frequency band does not include the first band transmission request information.

  In addition, the vehicle V3 on the road R2 has not received a message in the first frequency band from the vehicle V1 at this time. On the other hand, the vehicle V3 receives the message from the vehicle V2 in the first frequency band. However, since the first band transmission request information is not included in the message received from the vehicle V2, the vehicle V3 transmits the message in the second frequency band.

  Further, as shown in FIG. 8C, when the vehicle V1 on the road R1 stops near the junction J1, and the vehicles V2 and V3 on the road R2 further approach the junction J1, the vehicle V3 A message is received from the vehicle V1 in the frequency band. For this reason, the vehicle V3 transmits a message in the first frequency band. Thereby, all of vehicles V1, V2, and V3 will be in the condition which transmits a message in the 1st frequency band.

  Next, as shown in FIG. 8 (d), when the vehicle V1 on the road R1 stops near the junction J1, and the vehicles V2 and V3 on the road R2 pass through the junction J1, the vehicle V2 Since the message is not received from the vehicle V1 in the frequency band, the transmission in the first frequency band is stopped and the message is transmitted in the second frequency band. On the other hand, the vehicles V1 and V3 continue message transmission in the first frequency band.

  Thereafter, as shown in FIG. 8 (e), when the vehicle V1 joins the road R2 at the junction J1 and passes through the junction J1 on the road R2, the transmission in the first frequency band is stopped, and the second frequency Send a message in a band. Accordingly, since the vehicle V3 does not receive a message from the vehicle V1 in the first frequency band, the transmission in the first frequency band is stopped and the message is transmitted in the second frequency band. Further, since the vehicle V4 traveling on the road R2 behind the vehicle V1 has not received a message from the vehicle V1 in the first frequency band, it transmits a message in the second frequency band.

  As shown in FIG. 9, when the vehicle V1 on the road R1 is stopped near the junction J1, a message including the first band transmission request information is transmitted in the first frequency band. Then, the vehicle V2 approaching the junction J1 on the road R2 receives the message from the vehicle V1 in the first frequency band, and therefore transmits the message in the first frequency band. Further, the vehicle V5 moving away from the junction J1 on the road R1 also receives a message from the vehicle V1 in the first frequency band. However, the vehicle V5 determines that there is no possibility that the vehicle V5 and the vehicle V1 cross each other, and transmits a message in the second frequency band.

The in-vehicle device 1 configured as described above includes a first band communication unit 11, a second band communication unit 12, and a facilitation unit 14.
The first band communication unit 11 transmits and receives data wirelessly using a preset first frequency band. The second band communication unit 12 transmits and receives data wirelessly using a second frequency band that is set differently from the first frequency band.

The facilitation unit 14 acquires at least vehicle position information and vehicle state information, and constructs a transmission message (S540).
The facilitation unit 14 determines whether or not to transmit the constructed transmission message (hereinafter referred to as the own vehicle transmission message) to the first band communication unit 11, and based on the determination result, the first band transmission request flag Is set (S20 to S50).

  Whether the facilitation unit 14 includes first band transmission request information indicating that a message received from another vehicle (hereinafter referred to as another vehicle reception message) requests data transmission in the first frequency band. Based on this, it is determined whether or not the vehicle transmission message is transmitted to the first band communication unit 11, and based on the determination result, a first band transmission flag is set (S120, S130, S160).

  The facilitation unit 14 transmits the own vehicle transmission message to the first band communication unit 11 or the second band communication unit 12 based on the first band transmission request flag and the first band transmission flag (S610 to S640).

The facilitation unit 14 adds the first band transmission request information to the own vehicle transmission message when the first band transmission request flag is set (S550, S560).
The in-vehicle device 1 configured as described above includes a first band communication unit 11 that performs data communication using the first frequency band and a second band communication unit 12 that performs data communication using the second frequency band. At least one of them transmits the own vehicle transmission message. For this reason, when a plurality of vehicles equipped with the in-vehicle device 1 of the present invention perform inter-vehicle communication, it is possible to suppress the concentration of communication traffic in either the first frequency band or the second frequency band. .

  The in-vehicle device 1 determines whether or not to transmit the own vehicle transmission message to the first band communication unit 11. For this reason, the in-vehicle device 1 can perform data in a frequency band other than the first frequency band when it is determined that the transmission of the own vehicle transmission message by the first band communication unit 11 is unnecessary. . For this reason, when a plurality of vehicles equipped with the in-vehicle device 1 perform inter-vehicle communication, an increase in the number of vehicles performing data transmission in the first frequency band can be suppressed, and communication traffic in the first frequency band. Concentration can be suppressed.

  Further, the in-vehicle device 1 determines whether or not to transmit the own vehicle transmission message to the first band communication unit 11 based on whether or not the first band transmission request information is included in the other vehicle reception message. For this reason, when the in-vehicle device 1 determines that the other vehicle is requesting data transmission in the first frequency band from the own vehicle based on the first band transmission request information, the in-vehicle device 1 sets the first frequency band. It is possible to transmit the own vehicle transmission message.

  And the vehicle-mounted apparatus 1 adds 1st band transmission request information to the own vehicle transmission message, when it is judged that the own vehicle transmission message is transmitted to the 1st band communication part 11. FIG. For this reason, in the case where a plurality of vehicles equipped with the in-vehicle device 1 perform inter-vehicle communication, the in-vehicle device 1 receives the other vehicle even when the other vehicle reception message is received from the other vehicle in the first frequency band. Based on whether or not the first band transmission request information is included in the message, it can be determined whether or not the transmission source of the received other vehicle reception message requests transmission in the first frequency band. And if the in-vehicle device 1 determines that the transmission source does not request transmission in the first frequency band, the in-vehicle device 1 may not transmit the own vehicle transmission message using the first frequency band. it can. That is, the in-vehicle device 1 can request transmission of a message using the first frequency band by limiting to the range where the own vehicle transmission message reaches from the own vehicle.

  Accordingly, the in-vehicle device 1 can limit the number of in-vehicle devices that transmit a message using the first frequency band in response to a request from the own vehicle to a range where a message transmitted by the own vehicle reaches. Concentration of communication traffic in the first frequency band can be suppressed.

  The in-vehicle device 1 also includes information indicating the position and state of the host vehicle, information indicating the surrounding situation of the host vehicle, vehicle position information and vehicle state information (that is, positions of other vehicles) included in the transmission method determination data. And the information indicating the state), it is determined whether or not there is a possibility that the own vehicle and the other vehicle are mixed (S140).

  And even if it is a case where it is judged that vehicle equipment 1 is requesting data transmission in the 1st frequency band based on the 1st band transmission request information contained in other vehicles reception message (S120: YES), When it is determined that there is no possibility that the host vehicle and the other vehicle are mixed (S150: NO), the first band transmission flag is cleared (S170).

  Thereby, the vehicle-mounted apparatus 1 can suppress the occurrence of a situation where a message is wastedly transmitted in the first frequency band even though message transmission in the first frequency band is unnecessary. For this reason, the in-vehicle device 1 can further suppress the concentration of communication traffic in the first frequency band.

  In the embodiment described above, the in-vehicle device 1 is the wireless communication device in the present invention, the first band communication unit 11 is the first wireless communication unit in the present invention, and the second band communication unit 12 is the second wireless communication unit in the present invention. is there.

  Further, the process of S540 is the message creating means in the present invention, the processes of S20 to S50 are the own vehicle transmission determining means in the present invention, the processes of S120, S130, S150, S160 and S170 are the other vehicle transmission determining means in the present invention, S610. The process of S640 is a transmission selection means in the present invention.

  Further, the processing of S550 and S560 is the additional means in the present invention, the first band transmission request information is the first frequency band request instruction information and the first frequency band transmission request information in the present invention, and the processing of S140 is the unnecessary determination means in the present invention. It is.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. In the second embodiment, parts different from the first embodiment will be described.

The in-vehicle device 1 of the second embodiment is the same as the first embodiment except that the other device transmission request process and the transmission method selection process are changed.
First, the other apparatus transmission request process of the second embodiment is the same as that of the first embodiment except that the processes of S910 and S920 are added.

  That is, as shown in FIG. 10, if there is a possibility that the own vehicle and another vehicle may cross each other at S150 (S150: YES), a preset reception determination period (this embodiment) at S910. Then, for example, it is confirmed whether the same message is received in the first frequency band and the second frequency band within 100 ms.

  In S920, it is determined whether the same message is received in the first frequency band and the second frequency band based on the confirmation result in S910. If the same message has not been received (S920: NO), the process proceeds to S160. On the other hand, when the same message is received (S920: YES), the process proceeds to S170.

Next, the transmission method selection process of the second embodiment is the same as that of the first embodiment except that the processes of S1010 to S1030 are executed instead of S620 to S640.
That is, as shown in FIG. 11, when a transmission message is input in S610 (S610: YES), first band transmission included in the transmission method instruction information input from transmission method determination unit 53 in S1010. It is determined whether the flag or the first band transmission request flag is set. If the first band transmission flag or the first band transmission request flag is set (S1010: YES), the input transmission message is output to the first band communication unit 11 in S1020, and S1030 Migrate to

On the other hand, when the first band transmission flag and the first band transmission request flag are cleared (S1010: NO), the process proceeds to S1030.
In step S1030, the input transmission message is output to the second band communication unit 12, and the transmission method selection process is temporarily terminated.

Next, a specific example of the operation of the in-vehicle device 1 configured as described above will be described.
For example, as shown in FIG. 12, when the vehicle V1 on the road R1 is stopped near the junction J1, the vehicle V1 sends a message including the first band transmission request information to the first frequency band and the second frequency. Send in a band. And the vehicle V2 approaching the junction J1 on the road R2 receives the message from the vehicle V1 in the first frequency band. However, the vehicle V2 receives the message from the vehicle V1 even in the second frequency band within the reception determination period. For this reason, the vehicle V2 does not transmit in the first frequency band, but transmits a message in the second frequency band.

  The in-vehicle device 1 configured as described above determines whether or not the same other vehicle reception message is received in the first frequency band and the second frequency band within a preset reception determination period (S910). And even if it is a case where 1st band transmission request information is contained in the other vehicle reception message (S120: YES), the vehicle-mounted apparatus 1 will judge that it received the same other vehicle reception message (S920: YES). ), The first band transmission flag is cleared (S170).

  Thereby, the in-vehicle device 1 can suppress the occurrence of a situation in which the message is wastedly transmitted in the first frequency band even though the same other vehicle reception message is received in the second frequency band. it can. For this reason, the in-vehicle device 1 can further suppress the concentration of communication traffic in the first frequency band.

  In the embodiment described above, the process of S910 is the same determination means in the present invention, and the processes of S120, S130, S160, S170, and S920 are other vehicle transmission determination means in the present invention.

(Third embodiment)
A third embodiment of the present invention will be described below with reference to the drawings. In the third embodiment, parts different from the first embodiment will be described.

The in-vehicle device 1 of the third embodiment is the same as that of the first embodiment except that the transmission method selection process is changed.
First, the transmission method selection process of the third embodiment is the same as that of the first embodiment except that the process of S1110 is executed instead of S630.

  That is, as shown in FIG. 13, in S1110, the input transmission message is output to the first band communication unit 11 at a message output cycle set in advance corresponding to the value indicated by the first transmission cycle information, The transmission method selection process is temporarily terminated. The message output cycle is set to be longer as the value indicated by the first transmission cycle information is larger.

Next, a specific example of the operation of the in-vehicle device 1 configured as described above will be described.
For example, as shown in FIG. 14, the road R3 and the road R4 intersect at a junction J2, and the vehicle V1 on the road R3 stops near the junction J2 to join the road R4, and the junction J2 It is assumed that many vehicles are traveling on the road R4 in the vicinity.

  The vehicle V1 stopped near the junction J2 transmits a message including the first band transmission request information in the first frequency band. On the road R4, the vehicle that exists within the range Rm that the message from the vehicle V1 reaches receives the message from the vehicle V1 in the first frequency band. This message includes first band transmission request information. For this reason, many vehicles existing near the junction J2 on the road R4 transmit messages in the first frequency band. However, a large number of vehicles and the vehicle V1 existing in the vicinity of the junction J2 on the road R4 transmit messages at a cycle according to the congestion degree of the first frequency band.

  The in-vehicle device 1 configured as described above determines the degree of congestion in the first frequency band (S330, S710 to S780). And the vehicle-mounted apparatus 1 changes the transmission period when transmitting the own vehicle transmission message by the 1st band communication part 11 according to the congestion degree of a 1st frequency band (S340-S390, S1110).

  Thereby, the in-vehicle device 1 can reduce the frequency of message transmission in the first frequency band when the first frequency band is congested, and further suppress the concentration of communication traffic in the first frequency band. can do.

  In the embodiment described above, the processes of S330 and S710 to S780 are the congestion state judging means in the present invention, and the processes of S340 to S390, S610, S620, S640 and S1110 are the transmission selecting means in the present invention.

(Fourth embodiment)
A fourth embodiment of the present invention will be described below with reference to the drawings. In the fourth embodiment, parts different from the first embodiment will be described.

The in-vehicle device 1 of the fourth embodiment is the same as that of the first embodiment except that the transmission message construction process and the other device transmission request process are changed.
First, the transmission message construction process of the fourth embodiment is the same as that of the first embodiment except that the processes of S1210 and S1220 are executed instead of S560 and S570.

  That is, as shown in FIG. 15, when the first band transmission request flag is not set in S550 (S550: NO), the first band indicating that there is no first band transmission request in S1210. The non-transmission request information is included in the transmission message constructed in S540, and this transmission message is output to the transmission method selection unit 42. Then, when the output of the transmission message is completed, the transmission message construction process is once ended.

  On the other hand, if the first band transmission request flag is set (S550: YES), the transmission message constructed in S540 is output to the transmission method selection unit 42 in S1220, and the transmission message construction process is temporarily terminated. To do.

Next, the other apparatus transmission request process of the fourth embodiment is the same as that of the first embodiment except that the process of S1310 is executed instead of S120.
That is, as shown in FIG. 16, when transmission method determination data is input in S110 (S110: YES), does transmission method determination data include first band non-transmission request information in S1310? Judge whether or not.

  If the first band non-transmission request information is included (S1310: YES), the process proceeds to S130. On the other hand, when the first band non-transmission request information is not included (S1310: NO), the process proceeds to S140.

Next, a specific example of the operation of the in-vehicle device 1 configured as described above will be described.
For example, as shown in FIG. 8A, the road R1 and the road R2 intersect at a junction J1, the vehicle V1 travels on the road R1 toward the junction J1, and the vehicles V2 and V3 meet. It is assumed that the vehicle is traveling on the road R2 toward J1. It is assumed that the road R2 is a priority road with respect to the road R1. Further, it is assumed that the vehicle V2 is traveling on the road R2 ahead of the vehicle V3. At this time, the vehicles V1, V2, and V3 are transmitting messages in the second frequency band (5.8 GHz band in the present embodiment).

  Then, as shown in FIG. 8B, when the vehicle V1 on the road R1 approaches the junction J1, a message that does not include the first band non-transmission request information is sent to the first frequency band (700 MHz band in this embodiment). )

  Further, when the vehicle V2 on the road R2 approaches the junction J1, the message from the vehicle V1 is received in the first frequency band. Since this message does not include the first band non-transmission request information, the vehicle V2 transmits the message in the first frequency band. However, the message transmitted by the vehicle V2 in the first frequency band includes the first band non-transmission request information.

  In addition, the vehicle V3 on the road R2 has not received a message in the first frequency band from the vehicle V1 at this time. On the other hand, the vehicle V3 receives the message from the vehicle V2 in the first frequency band. However, since the first band non-transmission request information is included in the message received from the vehicle V2, the vehicle V3 transmits the message in the second frequency band.

  Further, as shown in FIG. 8C, when the vehicle V1 on the road R1 stops near the junction J1, and the vehicles V2 and V3 on the road R2 further approach the junction J1, the vehicle V3 A message is received from the vehicle V1 in the frequency band. For this reason, the vehicle V3 transmits a message in the first frequency band. Thereby, all of vehicles V1, V2, and V3 will be in the condition which transmits a message in the 1st frequency band.

  Next, as shown in FIG. 8 (d), when the vehicle V1 on the road R1 stops near the junction J1, and the vehicles V2 and V3 on the road R2 pass through the junction J1, the vehicle V2 Since the message is not received from the vehicle V1 in the frequency band, the transmission in the first frequency band is stopped and the message is transmitted in the second frequency band. On the other hand, the vehicles V1 and V3 continue message transmission in the first frequency band.

  Thereafter, as shown in FIG. 8 (e), when the vehicle V1 joins the road R2 at the junction J1 and passes through the junction J1 on the road R2, the transmission in the first frequency band is stopped, and the second frequency Send a message in a band. Accordingly, since the vehicle V3 does not receive a message from the vehicle V1 in the first frequency band, the transmission in the first frequency band is stopped and the message is transmitted in the second frequency band. Further, since the vehicle V4 traveling on the road R2 behind the vehicle V1 has not received a message from the vehicle V1 in the first frequency band, it transmits a message in the second frequency band.

  Further, for example, as shown in FIG. 17, it is assumed that vehicles V11, V12, V13, and V14 are traveling on an opposite two-lane road R5. Vehicles V11 and V12 travel on lane L1 of lanes L1 and L2 of road R5, and vehicles V13 and V14 travel on lane L2. Further, it is assumed that the vehicle V11 can send and receive messages only in the first frequency band, and the vehicles V12, V13, and V14 can send and receive messages in both the first frequency band and the second frequency band.

  The vehicle V11 transmits a message that does not include the first band non-transmission request information in the first frequency band. Since the vehicles V12 and V13 exist in the vicinity of the vehicle V11, the messages from the vehicle V1 are received in the first frequency band. This message does not include the first band non-transmission request information. For this reason, vehicles V12 and V13 transmit a message in the first frequency band.

  On the other hand, since the vehicle V14 exists in the vicinity of the vehicle V11, the message from the vehicle V1 is received in the first frequency band. However, the vehicle V14 determines that there is no possibility of crossing with the vehicle V11, and transmits a message in the second frequency band.

The in-vehicle device 1 configured as described above includes a first band communication unit 11, a second band communication unit 12, and a facilitation unit 14.
The first band communication unit 11 transmits and receives data wirelessly using a preset first frequency band. The second band communication unit 12 transmits and receives data wirelessly using a second frequency band that is set differently from the first frequency band.

The facilitation unit 14 acquires at least vehicle position information and vehicle state information, and constructs a transmission message (S540).
The facilitation unit 14 determines whether or not to transmit the constructed transmission message (own vehicle transmission message) to the first band communication unit 11 and sets the first band transmission request flag based on the determination result. (S20-S50).

  The facilitation unit 14 is based on whether or not the message received from the other vehicle (other vehicle reception message) includes first band non-transmission request information indicating that data transmission in the first frequency band is not requested. Then, it is determined whether or not the vehicle transmission message is transmitted to the first band communication unit 11, and the first band transmission flag is set based on the determination result (S1310, S130, S160).

  The facilitation unit 14 transmits the own vehicle transmission message to the first band communication unit 11 or the second band communication unit 12 based on the first band transmission request flag and the first band transmission flag (S610 to S640).

  The facilitation unit 14 adds the first band non-transmission request information to the own vehicle transmission message when the first band transmission request flag is cleared (S550, S1210).

  The in-vehicle device 1 configured as described above determines whether or not to transmit the own vehicle transmission message to the first band communication unit 11 based on whether or not the first band non-transmission request information is included in the other vehicle reception message. Determine whether. For this reason, when the in-vehicle device 1 determines that the other vehicle is requesting data transmission in the first frequency band from the own vehicle based on the first band non-transmission request information, the first frequency band The self-vehicle transmission message can be transmitted using.

  And the vehicle-mounted apparatus 1 adds 1st band non-transmission request information to the own vehicle transmission message, when it is judged not to transmit the own vehicle transmission message to the 1st band communication part 11. FIG. For this reason, in the case where a plurality of vehicles equipped with the in-vehicle device 1 perform inter-vehicle communication, the in-vehicle device 1 receives the other vehicle even when the other vehicle reception message is received from the other vehicle in the first frequency band. Based on whether or not the first band non-transmission request information is included in the message, it can be determined whether or not the transmission source of the received other vehicle reception message requests transmission in the first frequency band. . And if the in-vehicle device 1 determines that the transmission source does not request transmission in the first frequency band, the in-vehicle device 1 may not transmit the own vehicle transmission message using the first frequency band. it can. That is, the in-vehicle device 1 can request transmission of a message using the first frequency band by limiting to the range where the own vehicle transmission message reaches from the own vehicle.

  Accordingly, the in-vehicle device 1 can limit the number of in-vehicle devices that transmit a message using the first frequency band in response to a request from the own vehicle to a range where a message transmitted by the own vehicle reaches. Concentration of communication traffic in the first frequency band can be suppressed.

  Further, as described above, the in-vehicle device 1 adds the first band non-transmission request information to the own vehicle transmission message when determining that the own vehicle transmission message is not transmitted to the first band communication unit 11 as described above. In other words, when transmitting the own vehicle transmission message to the first band communication unit 11, the first band non-transmission request information is not included in the own vehicle transmission message.

  In addition, a first band non-transmission is included in a transmission message transmitted by an in-vehicle device (hereinafter referred to as a non-compliant device) that can transmit and receive a message in the first frequency band and cannot transmit and receive a message in the second frequency band. Request information is not included.

  For this reason, when the in-vehicle device 1 receives a message from the non-compliant device in the first frequency band, the in-vehicle device 1 determines that the non-compliant device requests transmission in the first frequency band, and sends the message to the non-compliant device. A message can be transmitted in one frequency band.

  In the embodiment described above, the processes of S1310, S130, S160, and S170 are the other vehicle transmission determination means in the present invention, the processes of S550 and S1210 are the additional means in the present invention, and the first band non-transmission request information is the 1 frequency band request instruction information and first frequency band non-transmission request information.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
(Modification 1)
For example, in the fourth embodiment, the first embodiment is changed to use the first band non-transmission request information instead of the first band transmission request information. However, in the second and third embodiments, the first band non-transmission request information may be used instead of the first band transmission request information.

  In addition, the functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Moreover, you may abbreviate | omit a part of structure of the said embodiment. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claim are embodiment of this invention.

  DESCRIPTION OF SYMBOLS 1 ... In-vehicle apparatus, 11 ... 1st band communication part, 12 ... 2nd band communication part, 14 ... Facilitation part, 41 ... Transmission message construction part, 42 ... Transmission method selection part, 43 ... Reception message decomposition part, 44 ... Band state determination unit, 45 ... transmission method determination unit, 51 ... own device transmission request determination unit, 52 ... other device transmission request determination unit, 53 ... transmission method determination unit

Claims (6)

A wireless communication device (1) mounted on a vehicle,
First wireless communication means (11) for wirelessly transmitting and receiving data using a preset first frequency band;
Second wireless communication means (12) for wirelessly transmitting and receiving data using a second frequency band set in advance different from the first frequency band;
Message creation means (S540) for obtaining at least current vehicle information indicating the current position of the vehicle and the state of the vehicle, and creating a message;
Own vehicle transmission judgment means (S20 to S50) for judging whether or not to transmit the own vehicle transmission message, which is the message created by the message creation means, to the first wireless communication means;
Whether or not the other vehicle reception message, which is a message received from another vehicle different from the vehicle, includes first frequency band request instruction information indicating whether or not data transmission in the first frequency band is requested. Other vehicle transmission determination means (S120, S130, S150, S160, S170, S920) for determining whether to transmit the own vehicle transmission message to the first wireless communication means based on
Transmission selection means for transmitting the own vehicle transmission message to at least one of the first wireless communication means and the second wireless communication means based on the determination result by the own vehicle transmission determination means and the other vehicle transmission determination means ( S340 to S390, S610 to S640, S1110),
Radio communication apparatus comprising: adding means (S550, S560, S1210) for adding the first frequency band request instruction information to the own vehicle transmission message based on a determination result by the own vehicle transmission determining means . The first frequency band request instruction information is first frequency band transmission request information indicating that data transmission in the first frequency band is requested,
The adding means (S550, S560) sends the first frequency band transmission request information to the own vehicle when the own vehicle transmission judging means judges that the own vehicle transmission message is to be sent to the first wireless communication means. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is added to a transmission message. The first frequency band request instruction information is first frequency band non-transmission request information indicating that data transmission in the first frequency band is not requested.
The adding means (S550, S1210) sends the first frequency band non-transmission request information when the own vehicle transmission determining means determines that the own vehicle transmission message is not to be transmitted to the first wireless communication means. It adds to a vehicle transmission message. The radio | wireless communication apparatus of Claim 1 characterized by the above-mentioned. Based on the own vehicle information and the information included in the other vehicle reception message, comprising unnecessary determination means (S140) for determining whether or not data transmission in the first frequency band is unnecessary,
The other vehicle transmission judgment means (S120, S130, S150, S160, S170)
Even if it is determined that data transmission in the first frequency band is requested based on the first frequency band request instruction information included in the other vehicle reception message, the data in the first frequency band 4. The apparatus according to claim 1, wherein when the unnecessary determination unit determines that transmission is unnecessary, it is determined not to transmit the own vehicle transmission message to the first wireless communication unit. 5. A wireless communication device according to 1. The same determination means (S910) for determining whether or not the same other vehicle reception message is received in the first frequency band and the second frequency band within a preset reception determination period;
The other vehicle transmission judgment means (S120, S130, S160, S170, S920)
Even if it is determined that data transmission in the first frequency band is requested based on the first frequency band request instruction information included in the other vehicle reception message, the same other vehicle reception message is transmitted. 5. The apparatus according to claim 1, wherein when the same determination unit determines that the vehicle has been received, the host vehicle transmission message is determined not to be transmitted to the first wireless communication unit. 6. Wireless communication device. Congestion state determination means (S330, S710 to S780) for determining the congestion state of the first frequency band,
The transmission selection means (S340 to S390, S610, S620, S640, S1110)
Based on a determination result of the congestion state determination unit, a transmission cycle when the vehicle transmission message is transmitted by the first wireless communication unit is changed according to a congestion state of the first frequency band. The wireless communication apparatus according to any one of claims 1 to 5.