JP5050740B2 - Wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly perform communication between vehicles for preventing collision by suppressing the interference of communication. <P>SOLUTION: This radio communication equipment 1 broadcasts a communication packet in which the position coordinates and speed vectors of its own vehicle detected by a state detector 57 are described through a transmission part 21 to the outside in a preliminarily set transmission power and transmission cycle, and in detail, sets the transmission power and transmission cycle of the communication packet based on the communication packet received from the radio communication equipment of the other vehicle through a reception part 25, and sets the vehicle having the maximum absolute value of relative speed vectors among the vehicles around its own vehicle as a hazardous vehicle based on the speed vectors of the transmitting vehicle shown by the received communication packet, and switches the transmission power so as to become larger as the relative distance becomes long based on the relative distance and relative speed vector absolute value of the hazardous vehicle on the basis of its own vehicle, and switches the transmission cycle so as to become shorter as the relative speed vector absolute value becomes large. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a wireless communication device mounted on a vehicle.

  In recent years, it has been considered that vehicle information and the like are exchanged by mounting a wireless communication device on a vehicle such as an automobile and performing wireless communication between the vehicles. In such inter-vehicle communication, since communication is performed between moving vehicles, the communication environment greatly changes as the vehicle travels. For example, the density of surrounding vehicles varies greatly depending on whether the vehicle is traveling in a mountainous area or in an urban area. For this reason, in vehicle-to-vehicle communication, efficient communication cannot be performed if a communication packet is output from the wireless communication device with a fixed transmission power at all times.

  For example, in order to realize communication with a distant vehicle, it is better to set the transmission power high. However, if all vehicles communicate with a fixed high transmission power, communication interference is likely to occur. In particular, in the vicinity of an intersection or in a traffic jam area, the vehicle density is high. Therefore, if communication is performed with the same transmission power as that in an area where the vehicle density is low, communication interference increases and only inefficient communication is possible.

For this reason, in the conventional inter-vehicle communication, a function for adjusting the transmission power is provided in the wireless communication device, and the transmission power is adjusted by the wireless communication device of each vehicle according to the situation. For example, transmission power is adjusted in accordance with a relative distance and a relative speed with a communication destination vehicle (see Patent Document 1 and Patent Document 2).
JP 2007-6395 A JP 2004-343467 A

  By the way, for the purpose of avoiding a collision between vehicles, the present inventors periodically broadcast a communication packet storing vehicle information of the host vehicle to an unspecified number of surrounding vehicles. Consider exchanging vehicle information between the two. Even when vehicle-to-vehicle communication is realized in such a communication mode, if the transmission power of the communication packet is not adjusted, communication interference increases according to the environment around the vehicle such as the vehicle density, and collision occurs. There is a possibility that communication necessary for avoidance cannot be performed.

  However, conventionally, only a technique for adjusting the transmission power in communicating with a specific communication partner and a technique for adjusting the transmission power in communicating with an adjacent vehicle are known, No technology has been developed to adjust transmission conditions such as transmission power in order to avoid collisions between vehicles in an environment where an unspecified number of vehicles exist around the host vehicle and no communication partner is specified. .

  The present invention has been made in view of such problems, and in a communication system aimed at avoiding a collision between vehicles, an in-vehicle wireless capable of appropriately communicating between vehicles while suppressing communication interference. An object is to provide a communication device.

The wireless communication apparatus of the present onset bright has been made in order to achieve the above object, a wireless communication apparatus mounted on a vehicle having a detecting means for detecting the motion state of the vehicle, the packet transmitting unit, the packet receiving means , Reference vehicle setting means, and transmission condition setting means.

  In this wireless communication apparatus, the packet transmission means broadcasts a communication packet describing the movement state of the host vehicle as a radio signal around the host vehicle with a preset transmission power and transmission cycle based on the detection result of the detection means. To do. On the other hand, the packet receiving means receives a communication packet broadcast from a wireless communication device mounted on each unspecified vehicle existing around the host vehicle.

  Based on the contents of the communication packet received by the packet receiving means, the reference vehicle setting means evaluates the risk level of each transmission source vehicle that has transmitted the communication packet with respect to the own vehicle. The vehicle with the highest degree of danger with respect to the host vehicle is set as a reference vehicle as a transmission condition setting reference.

  Then, the transmission condition setting means sets at least one of transmission power and transmission cycle as the transmission condition based on the motion state of the reference vehicle with respect to the host vehicle set by the reference vehicle setting means. In the wireless communication apparatus configured as described above, the packet transmission unit broadcasts the communication packet with the transmission power and the transmission cycle that satisfy the transmission condition set by the transmission condition setting unit.

  As described above, in the wireless communication device of the present invention, a vehicle with a high degree of risk is selected from a group of vehicles located around the host vehicle based on information representing the motion state of the vehicle transmitted from another vehicle. The transmission conditions (transmission power and transmission cycle) are set in accordance with the motion state of the high-risk vehicle (reference vehicle). Therefore, according to this wireless communication device, communication packets can be broadcast under optimal transmission conditions in accordance with the danger approaching the host vehicle, and the communication environment of other vehicles is deteriorated by excessive output of radio waves. Therefore, the existence of the host vehicle can be appropriately notified to a vehicle that may cause danger to the host vehicle.

  Therefore, if vehicle-to-vehicle communication is performed using this wireless communication device, communication packets are generated by broadcasting communication packets with excessive transmission power or transmission cycle, and communication packets can be transmitted appropriately by other vehicles. It can be prevented as much as possible that other vehicles are in danger.

  That is, if this wireless communication device is used, in a communication system aiming at collision avoidance between vehicles, it is possible to suppress communication interference and to set transmission conditions as necessary and sufficient, and to communicate appropriately between vehicles. be able to.

In the above-described wireless communication apparatus, as the detecting means, a detecting means capable of detecting the speed vector of the host vehicle can be used. When this detecting means is used, the packet transmitting means as the motion state of the vehicle, Ru can be configured to describe the velocity vector of the vehicle.

  If the speed vectors are exchanged between the vehicles, each vehicle can obtain a relative speed vector between the own vehicle and the surrounding vehicles. Therefore, if vehicle-to-vehicle communication is performed using this wireless communication device, each vehicle can appropriately evaluate the degree of danger with respect to the own vehicle for the transmission source vehicle of each communication packet based on the relative speed vector. The transmission conditions can be set appropriately.

In addition, as the detection means, a detection means capable of detecting the position coordinates of the own vehicle can be used. When this detection means is used, the packet transmission means uses the position coordinates of the own vehicle as the movement state of the own vehicle. Ru can be in the configuration that describes the. By exchanging speed vectors and position coordinates between vehicles, each vehicle can accurately evaluate the risk of collision with surrounding vehicles from the relative speed and positional relationship with other vehicles. Therefore, if the wireless communication device is configured in this way, the transmission condition can be adjusted to a necessary and sufficient transmission condition capable of avoiding a collision, and communication can be appropriately performed between vehicles while suppressing communication interference. it can.

The reference vehicle setting means is configured to set, as a reference vehicle, a vehicle having the highest degree of danger among a group of vehicles existing within a predetermined distance with reference to the own vehicle in a group of transmission packets of communication packets. Ru can be.

  If the wireless communication device is configured in this way, the setting target of the reference vehicle can be limited to vehicles located within a predetermined range from the own vehicle, and the reference vehicle is set appropriately from the viewpoint of collision avoidance. Transmission conditions corresponding to the vehicle (reference vehicle) can be set.

In addition, the reference vehicle setting means includes a relative speed vector of the transmission source vehicle with reference to the own vehicle in the transmission source vehicle group, and a vector having the existence point of the transmission source vehicle as a start point and the existence point of the own vehicle as an end point. and the angle, in but in the following vehicle group threshold, the risk is greatest vehicle, but it may also be a configuration of setting the reference vehicle.

  By configuring the wireless communication device in this way, it is possible to set the reference vehicle from among the vehicle group that is moving toward the own vehicle side, and set the reference vehicle appropriately. can do.

In addition, the wireless communication device includes a road on which the transmission source vehicle travels based on the position coordinates of the own vehicle and the position coordinates of the transmission source vehicle described in the communication packet for each communication packet received by the packet reception unit. Is provided with road relationship determination means for determining whether or not the road on which the vehicle travels satisfies a predetermined relationship, and the reference vehicle setting means transmits the communication packet according to the determination result of the road relationship determination means. of the original vehicle group, in the vehicle group traveling road which satisfies the road a predetermined relationship which the vehicle is traveling, the risk is greatest vehicle, but it may also be a configuration of setting the reference vehicle. Even if the wireless communication device is configured in this manner, the reference vehicle can be set appropriately.

In addition, the reference vehicle setting means has the highest risk in the vehicle group in which no other vehicle exists between the transmission source vehicle location and the own vehicle location in the transmission source vehicle group. the vehicle, but it may also be configured to be set to the reference vehicle.

  For a transmission source vehicle in which another vehicle exists between itself and the own vehicle, there is no risk that the transmission source vehicle directly collides with the own vehicle. Therefore, if a vehicle with the highest degree of danger is selected from a group of vehicles in which no other vehicle exists between the location of the source vehicle and the location of the host vehicle in the source vehicle group, The reference vehicle can be selected by removing the low-grade vehicle, and the reference vehicle can be set appropriately.

The transmission condition setting unit, a motion state of the reference vehicle, based on the relative distance with respect to the vehicle of the reference vehicle, Ru can be configured to set the transmission power. Specifically, the transmission condition setting means, as the relative distance is long, not good when it is in the configuration to be set to a large value of transmission power.

  If the wireless communication device is configured in this way, communication packets can be transmitted with appropriate transmission power according to the distance (relative distance) between the reference vehicle and the host vehicle, which is necessary and sufficient for avoiding a collision. With the transmission power, communication packets can be transmitted around the vehicle. In other words, according to the wireless communication apparatus of the present invention, it is not necessary to transmit communication packets with excessive transmission power, and communication interference can be prevented as much as possible.

In addition, the risk level can be evaluated based on the magnitude of the relative speed vector of the transmission source vehicle with reference to the host vehicle, and the reference vehicle setting means uses the host vehicle as a reference with the maximum risk level. and the maximum source vehicle magnitude of relative velocity vector, Ru can be configured to set the reference vehicle.

  However, with such a device configuration, the reference vehicle is set according to the magnitude of the relative speed vector regardless of the moving direction of the vehicle, so that the vehicle that is moving away from the host vehicle is set as the reference vehicle. there is a possibility.

Therefore, it is preferable to configure the reference vehicle setting means as follows. That is, the reference vehicle setting means has the largest inner product of the relative velocity vector of the transmission source vehicle with reference to the own vehicle and the unit vector extending from the location of the transmission source vehicle toward the location of the own vehicle. the vehicle, as the largest vehicle risk, have good when it is in a circuit which sets the reference vehicle.

  In this way, if the wireless communication device is configured, the transmission condition can be set based on the vehicle moving at high speed toward the own vehicle, and the communication packet is transmitted under the transmission condition suitable for collision avoidance. can do. For example, according to this wireless communication device, it is not necessary to set a vehicle that is traveling at a high speed but is moving away from the own vehicle as a reference vehicle in preference to a vehicle that faces the own vehicle. By setting the going vehicle as the reference vehicle, it is possible to prevent the transmission power from becoming excessively high.

In addition, the reference vehicle setting means determines, for each transmission source vehicle that has transmitted the communication packet, whether or not there is a possibility that the transmission source vehicle will collide with the own vehicle, and if it is determined that there is a possibility of collision In addition, the remaining time until the collision is predicted, and the vehicle with the smallest remaining time until the collision is selected from the group of transmission source vehicles determined to have the possibility of the collision as the vehicle with the highest risk. but it may also be configured to be set to the vehicle.

  When the danger of a collision is imminent, it is preferable to shorten the transmission cycle and quickly transmit information about the host vehicle to the dangerous vehicle. However, if the transmission cycle is set short in advance, there is a risk of a collision. When not imminent, communication packets are transmitted with an excessive transmission period, causing communication interference and degrading the communication environment of other vehicles.

  On the other hand, according to the wireless communication device of the present invention, the vehicle having the shortest remaining time until the collision is set as the reference vehicle, and the transmission condition is set according to the reference vehicle. Therefore, the transmission cycle is excessively shortened. It is not necessary to set, and it is possible to realize efficient communication by suppressing communication interference.

When the reference vehicle setting means is configured as described above, the transmission condition setting means may be configured as follows. In other words, the transmission condition setting means, the reference vehicle is based on the length of the remaining time until the collision with the vehicle, not good when it is in a circuit which sets the transmission period. More, the transmission condition setting means, the shorter the time remaining until the collision has good when it is in the configuration to set the transmission period to a shorter value.

  If the transmission cycle is set based on the remaining time until the collision as in the wireless communication device of the present invention, communication packets can be transmitted at an appropriate transmission cycle according to the collision risk, and excessive transmission is performed. By setting the cycle, it is possible to prevent as much as possible that the other vehicle is not properly transmitted and that the other vehicle is in danger.

In addition, in each of the radio communication apparatus described above, the transmission condition setting means, based on the size of the relative velocity vector of the reference vehicle relative to the vehicle, but it may also be a configuration of setting a transmission cycle. In this case, the transmission condition setting unit, the larger the magnitude of the relative velocity vector, Ru can be configured to set the transmission period to a shorter value.

  If a transmission cycle is set based on the relative speed vector of a high-risk reference vehicle, a communication packet is transmitted at a transmission cycle corresponding to the degree of danger, and the vehicle is quickly Since information can be transmitted, vehicle control for collision avoidance can be accurately performed in each vehicle, and collision can be avoided with high probability.

Further, the transmission condition setting means includes a reference vehicle represented by an inner product of a relative speed vector of the reference vehicle with reference to the own vehicle and a unit vector extending from the reference vehicle location to the location of the own vehicle. velocity component of the vehicle direction, based on, when the configuration for setting the transmission period, have more preferable. In this case, the transmission condition setting means, as the velocity component is greater, Ru can be configured to set the transmission period to a shorter value.

  If a transmission cycle is set based on the speed component of the reference vehicle in the direction of the host vehicle, communication packets can be transmitted at a transmission cycle that matches the speed of the vehicle that is moving toward the host vehicle at high speed. Thus, information on the host vehicle can be quickly transmitted to a vehicle traveling at a high speed. Therefore, by using this wireless communication apparatus, it is possible to appropriately set transmission conditions and perform communication between vehicles for the purpose of collision avoidance.

  Further, in the above wireless communication device, the packet transmission means indicates the motion state of the reference vehicle set in the own vehicle based on the content of the communication packet received in the past from the reference vehicle set in the own vehicle. The communication packet described together with the motion state of the above may be broadcasted. If the packet transmission means is configured in this way, the information on the reference vehicle can be exchanged between the corresponding wireless communication apparatuses.

In addition, when the packet transmission unit is configured in this way, each time the packet reception unit receives a communication packet in the wireless communication device, the reference set in the transmission source vehicle of the communication packet indicated by the received communication packet A change necessity determination means for determining whether or not it is necessary to change the reference vehicle set in the own vehicle based on the motion state of the vehicle may be provided. Then, when the reference vehicle setting means determines that it is necessary to change by the change necessity determination means, the reference vehicle set as the transmission source vehicle is replaced with the current vehicle instead of the currently set reference vehicle. of not good when it is in the configuration to be set to the reference vehicle.

The reference vehicle setting means determines that the reference vehicle needs to be changed when the risk of the reference vehicle set as the transmission source vehicle is higher than the reference vehicle set as the own vehicle. If the risk of the reference vehicle set as the transmission source vehicle is lower than that of the reference vehicle set as the own vehicle, it is determined that it is not necessary to change the reference vehicle. can Ru.

If the wireless communication device is configured in this manner, the reference vehicle of the host vehicle can be changed to a more appropriate vehicle based on the information on the reference vehicle set for the other vehicle.
For example, there may be an environment where a communication packet from a vehicle with a high degree of danger cannot be received by the host vehicle due to a radio wave obstacle such as a high-rise building. In this case, if the information on the reference vehicle is exchanged between the vehicles, the information on the vehicle having a high degree of risk can be acquired via the other vehicle. Therefore, according to this wireless communication apparatus, it is possible to change the setting of the reference vehicle of the host vehicle to a more appropriate vehicle.

  In addition, when describing the movement state of the reference vehicle in the communication packet, each time the packet receiving unit receives the communication packet, the reference set in the transmission source vehicle of the communication packet based on the content of the received communication packet. The wireless communication apparatus may be provided with the same determination means for determining whether the vehicle and the reference vehicle set as the host vehicle are the same vehicle.

  Further, in this wireless communication device, when the reference vehicle set as the transmission source vehicle and the reference vehicle set as the own vehicle are the same vehicle, the reference vehicle, the transmission source vehicle, and the own vehicle Based on this positional relationship, it is preferable to provide a change necessity determination means for determining whether or not it is necessary to change the reference vehicle set for the host vehicle.

Then, when the reference vehicle setting means determines that the change necessity determination means needs to be changed, a vehicle having a risk level next to the currently set reference vehicle is set as the current risk level for the host vehicle. instead of the reference vehicle which are, have good when it is in a circuit which sets the reference vehicle of the own vehicle.

  As an environment in which the vehicles located around the own vehicle set the same reference vehicle, for example, the own vehicle and the other vehicle are traveling on the same lane, and the reference vehicle is behind the own vehicle and the other vehicle. An approaching environment can be considered. However, in this case, since the own vehicle and the other vehicle are in the same motion state at substantially the same position, each vehicle can communicate with the reference vehicle with a high transmission power and a short transmission cycle. The danger of a collision can be avoided even if it is not transmitted.

  Therefore, in the present invention, when the own vehicle and the other vehicle set the same reference vehicle, the reference vehicle of the own vehicle is changed based on the positional relationship between the other vehicle, the own vehicle, and the reference vehicle. It is determined whether or not it is necessary, and if necessary, the reference vehicle of the host vehicle is changed to the next candidate. If vehicle-to-vehicle communication is performed using the wireless communication device configured as described above, for example, when the following vehicle is coming to the tail of the vehicle train in a traffic jam, the vehicles around the tail are all at once. By increasing the transmission power and communicating, it is possible to prevent the position information around the tail end from being transmitted to the following vehicle due to interference, and more preferably between the vehicles. Communication can be performed. Therefore, this wireless communication apparatus is very useful for collision avoidance.

If the distance from the reference vehicle to the transmission source vehicle is shorter than the distance from the reference vehicle to the host vehicle, the change necessity determination unit needs to change the reference vehicle set in the host vehicle. not good when it is in determining the configuration. If the change necessity determination unit is configured in this way, it is possible to prevent the surrounding vehicles from generating communication interference as much as possible by simultaneously increasing the transmission power or shortening the transmission cycle by simple determination. be able to.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory diagram showing the configuration of a wireless communication apparatus 1 to which the present invention is applied. The wireless communication apparatus 1 according to the present embodiment is used for exchanging vehicle information between a plurality of vehicles, and is mounted on each vehicle to constitute a vehicle-to-vehicle communication system.

  Specifically, the wireless communication device 1 includes a microcomputer and the like, and a control unit 10 that performs overall control of each part in the device, and a communication unit 20 that is controlled by the control unit 10 and wirelessly communicates with other wireless communication devices 1. . The wireless communication device 1 is connected to a navigation device 50 that is separately mounted on the vehicle and mounted on the vehicle.

  The communication unit 20 transmits a communication packet that stores a position coordinate and a velocity vector of the host vehicle as vehicle information representing the motion state of the host vehicle, and a communication packet from a radio signal received from the outside via an antenna. And a receiving unit 25 that inputs this to the control unit 10.

  The transmission unit 21 is configured to generate the communication packet at a preset transmission cycle and transmit (broadcast) the communication packet as a radio signal. The transmitter 21 transmits the radio signal from the antenna with a preset transmission power. Output to. Note that the setting values of the transmission cycle and the transmission power are held in a register included in the transmission unit 21, and each setting value held in the register is updated by the control unit 10.

  FIG. 2A is an explanatory diagram illustrating a configuration of a communication packet generated by the transmission unit 21. As shown in FIG. 2A, the communication packet generated by the transmission unit 21 and exchanged between vehicles includes header information indicating the packet number, the position coordinates of the host vehicle, and the speed vector of the host vehicle. It is configured. The transmission unit 21 repeatedly executes the process shown in FIG. 2B, so that the communication packet having the configuration shown in FIG. 2A is externally (automatically) as a radio signal with a preset transmission cycle and transmission power. Broadcast around the vehicle).

  FIG. 2B is a flowchart showing packet transmission processing repeatedly executed by the transmission unit 21. When the packet transmission process is started, the transmission unit 21 waits until the value of the counter indicating the elapsed time after the packet transmission becomes equal to or longer than the transmission cycle set in the register in advance.

  When the counter value is equal to or greater than the transmission cycle (Yes in S110), the communication packet stores header information in which the next number obtained by adding 1 to the packet number given at the previous packet transmission is stored as a packet number, 10 generates a communication packet in which the latest position coordinates and speed vector of the host vehicle input from 10 are described as vehicle information (S120), and the generated communication packet is transmitted as a radio signal through an antenna with transmission power set in a register. Broadcast to the outside (S130).

  Thereafter, the transmission unit 21 resets the counter value to zero (S140), and once ends the packet transmission process. The transmission unit 21 broadcasts a communication packet storing the position coordinates and speed vector of the host vehicle to the outside for each preset transmission cycle by repeatedly executing the packet transmission process having such contents.

Information on the position coordinates and speed vector of the host vehicle input from the control unit 10 to the transmission unit 21 is provided from the navigation device 50 connected to the wireless communication device 1.
The navigation device 50 includes link data, node data, and the like, a map database (DB) 51 representing the position and connection relationship of each road laid throughout the country, a display unit 53 including a liquid crystal display, a speaker, and various guide voices. A state in which the position coordinates of the own vehicle and the speed vector of the own vehicle are detected by the absolute coordinate system, which is composed of the output voice output unit 55 and a GPS receiver or an autonomous navigation sensor (for example, a wheel speed sensor or a gyroscope). A detector 57 is provided.

  The control unit 10 of the wireless communication device 1 inputs information on the position coordinates and speed vector of the host vehicle obtained from the state detector 57 of the navigation device 50 connected so as to be communicable with itself to the transmission unit 21, and A communication packet describing the position coordinates and velocity vector of the vehicle is broadcast to the surroundings of the host vehicle in the form of a radio signal by the transmission unit 21.

  Further, the wireless communication device 1 according to the present embodiment is based on the communication packet received through the receiving unit 25 from the same type of wireless communication device mounted on other vehicles around the own vehicle, and vehicle information of each vehicle located around the own vehicle. A function of transmitting (position coordinates and velocity vector) to the navigation device 50 and an external ECU that controls the vehicle connected to the in-vehicle LAN is provided.

With this function, the wireless communication device 1 provides vehicle information around the host vehicle to the navigation device 50 and the external ECU.
On the other hand, the navigation device 50 receives the vehicle information and arranges the symbols of the vehicles located around the host vehicle on the map screen displayed on the display unit 53, for example, as shown in FIG. Make it possible to grasp the vehicle layout around the vehicle. In an emergency, an alarm sound is output through the audio output unit 55 in order to avoid a collision between vehicles. Further, the external ECU receives this vehicle information, and performs steering control, brake control, etc. in an emergency, and performs vehicle control for collision avoidance.

  Subsequently, a dangerous vehicle setting process executed by the wireless communication device 1 based on a communication packet received from a wireless communication device of another vehicle will be described. FIG. 3 is a flowchart showing the dangerous vehicle setting process repeatedly executed by the control unit 10 of the wireless communication device 1.

  The control unit 10 has the maximum degree of danger for the host vehicle based on the communication packet received from the same type of wireless communication device mounted on each unspecified vehicle that is present in the communication range (around the host vehicle). The vehicle is identified, and the transmission power and the transmission cycle are set for the transmission unit 21 based on the motion state of the vehicle. In this way, the wireless communication device 1 broadcasts communication packets with transmission power and transmission period that are necessary and sufficient for collision avoidance so that communication interference does not occur between vehicles as much as possible. The dangerous vehicle setting process shown in FIG. 3 is executed by the control unit 10 in order to identify the vehicle with the highest degree of danger and adjust the transmission power and the transmission cycle.

  When the dangerous vehicle setting process is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet from the outside, and determines that the communication packet has not been received (No in S210), the process proceeds to S290. When it is determined that the communication packet has been received (Yes in S210), the process proceeds to S220.

  After shifting to S220, the control unit 10 determines the position coordinate Xs and speed vector Vs of the own vehicle obtained from the state detector 57, and the position coordinate X and speed vector V of the packet transmission source vehicle described in the received packet. Based on the own vehicle, the relative distance D of the packet transmission source vehicle and the absolute value δV of the relative velocity vector are calculated. Specifically, D = | X−Xs | is calculated as the relative distance D, and δV = | V−Vs | is calculated as the relative velocity vector absolute value δV.

Then, when the calculation of the values D and δV is finished, the process proceeds to S230, and it is determined whether or not a dangerous vehicle is set.
Whenever the control unit 10 of the present embodiment receives a communication packet from the wireless communication device of another vehicle, the control unit 10 registers the movement state of the packet transmission source vehicle in the surrounding vehicle list stored in the RAM built in the control unit 10. It is configured. FIG. 4 is an explanatory diagram showing the configuration of the surrounding vehicle list.

  Specifically, every time a communication packet is received, the control unit 10 includes, in the surrounding vehicle list, a packet number indicated by the received communication packet, a position coordinate Xr and a velocity vector Vr of the packet transmission source vehicle, and the own vehicle as a reference. The relative distance Dr of the packet transmission source vehicle, the relative speed evaluation value δVr of the packet transmission source vehicle, which will be described later, the time stamp Tr indicating the reception time of the communication packet, and whether or not the packet transmission source vehicle is a dangerous vehicle. It is configured to register a record composed of a dangerous vehicle flag to be represented. The dangerous vehicle flag takes a value of 0 or 1.

  In S230, the control unit 10 determines whether or not a dangerous vehicle is set by referring to the dangerous vehicle flag of each record registered in the surrounding vehicle list. Specifically, in S230, if the dangerous vehicle flag of any record registered in the surrounding vehicle list is not set to the value 1, it is determined that no dangerous vehicle is set (No in S230), and the surrounding vehicle list If any of the dangerous vehicle flags in the record registered in is set to the value 1, it is determined that the dangerous vehicle is set (Yes in S230). If no record is registered in the surrounding vehicle list, it is determined that no dangerous vehicle is set.

  If it is determined in S230 that a dangerous vehicle is not set, the control unit 10 proceeds to S260 and determines that the packet transmission source vehicle is “high risk” with respect to the own vehicle. On the other hand, if it is determined that a dangerous vehicle is set, the process proceeds to S240.

  In S240, the control unit 10 obtains the value δVr indicated by each record registered in the surrounding vehicle list, and the relative velocity vector absolute value δV of the packet transmission source vehicle obtained in S220 based on the communication packet received this time. To determine whether the relative velocity vector absolute value δV obtained in S220 is greater than any of the values δVr indicated by the records registered in the surrounding vehicle list (S250). Although details will be described later, in this embodiment, the relative speed vector absolute value δV of the vehicle corresponding to the record is described as the relative speed evaluation value δVr in each record of the surrounding vehicle list.

  When the control unit 10 determines that the relative velocity vector absolute value δV of the packet transmission source vehicle obtained in S220 is greater than the value δVr of any record registered in the surrounding vehicle list (Yes in S250), the packet transmission source It is determined that the vehicle is “high risk” with respect to the host vehicle (S260). Thereafter, the process proceeds to S280.

  On the other hand, if it is determined that the relative velocity vector absolute value δV of the packet transmission source vehicle obtained in S220 is the same as or smaller than any of the values δVr indicated by the records registered in the surrounding vehicle list (No in S250). Then, it is determined that the packet transmission source vehicle is “low risk” for the host vehicle (S270). Thereafter, the process proceeds to S280.

  In S280, the control unit 10 executes an update setting process illustrated in FIG. FIG. 5 is a flowchart showing the update setting process executed by the control unit 10. When the update setting process shown in FIG. 5 is started, the control unit 10 is presumed to be the same vehicle as the transmission source vehicle of the communication packet received this time from the surrounding vehicle list based on the packet number indicated by the communication packet received this time. Records to be searched (S310).

  As described above, the packet numbers are assigned sequentially to the communication packets to be transmitted in each wireless communication device 1. Accordingly, in S310, a record indicating a packet number PN (PN0> PN> PN0-α) in a range larger than the value (PN0-α) and smaller than the value PN0 with the packet number PN0 indicated by the current received packet as a reference, Search is made as a record presumed to be the same vehicle as the current packet transmission source vehicle. The value α can be arbitrarily determined by an integer value of 2 or more.

  When the corresponding record exists in the surrounding vehicle list (Yes in S320), the process proceeds to S325. On the other hand, when the corresponding record does not exist in the surrounding vehicle list (No in S320), the process proceeds to S365.

  If transfering to S325, the control part 10 will set all the applicable records to the candidate of an update object. When this process is finished, it is determined whether or not a record of the same vehicle as the current packet transmission source vehicle can be specified among the set update target candidates (S330).

  For example, in S330, there is only one record set as the update target candidate, and the packet number PN indicated by the record set as the update target candidate is the packet number PN0 indicated by the communication packet received this time. If it is a serial number (that is, PN = PN0-1), it is determined that the record of the same vehicle as the current packet transmission source vehicle can be specified (Yes in S330). On the other hand, in other cases, it is determined that the record of the same vehicle as the current packet transmission source vehicle cannot be specified (No in S330).

  If the control part 10 judges that it can specify here (it is Yes at S330), it will transfer to S335 and will set the record specified as a record of the same vehicle to an update object record. Thereafter, the process proceeds to S375.

  On the other hand, when determining that it cannot be specified (No in S330), the control unit 10 proceeds to S340, and sets one of the records set as the update target candidate as the processing target. Thereafter, the process proceeds to S345, and the current position coordinate Xn of the vehicle corresponding to this record is estimated from the information of the vehicle position coordinate Xr, the velocity vector Vr, and the time stamp Tr indicated by the processing target record. For example, assuming that the vehicle is moving at a constant speed, the current position coordinate Xn is estimated as Xn = Xr + Vr · ΔT. However, ΔT is the difference between the current time and the time stamp Tr.

  When the process in S345 is finished, the control unit 10 calculates an error ε = | X−Xn | between the position coordinate X of the packet transmission source vehicle indicated by the communication packet received this time and the estimated position coordinate Xn. (S350). After that, it is determined whether or not the error ε has been calculated by setting all records set as candidates for update to be processed (S355), and if it is determined that the error ε has not been calculated for all records (S355). No), the process proceeds to S340, one unprocessed record is set as a processing target, and the processes after S345 are executed.

  If it is determined that all records set as candidates for updating are set as processing targets and the error ε is calculated (Yes in S355), the control unit 10 proceeds to S360 and determines the error ε of each record. In one group, it is determined whether or not the error ε taking the minimum value is equal to or less than a preset threshold value.

  If it is determined that the minimum value of the error ε is equal to or smaller than the threshold (Yes in S360), the process proceeds to S370, and the record with the minimum error ε is selected from the record group set as the update target candidate. It is determined that the record is the same vehicle as the transmission source vehicle, and the record with the smallest error ε is set as the update target record. Thereafter, the process proceeds to S375.

Moreover, if transfering to S375, the control part 10 will update the content of the update object record based on the packet number and vehicle information which were described in the communication packet received this time.
Specifically, the packet number indicated by the update target record is updated to the packet number indicated by the currently received communication packet, and the position coordinate Xr indicated by the update target record is updated to the position of the packet transmission source vehicle indicated by the currently received communication packet. The coordinate vector X is updated, and the speed vector Vr indicated by the update target record is updated to the speed vector V of the packet transmission source vehicle indicated by the communication packet received this time.

  Similarly, the relative distance Dr indicated by the update target record is updated to the relative distance D calculated in S220 based on the communication packet received this time, and the relative speed evaluation value δVr indicated by the update target record is updated to the communication packet received this time. Based on this, the relative speed vector absolute value δV calculated in S220 is updated. Also, the time stamp Tr is updated to the current time. However, here, the dangerous vehicle flag of the update target record is not updated.

In this way, when the content of the update target record is updated in S375, the control unit 10 proceeds to S380.
On the other hand, if it is determined in S360 that the minimum value of the error ε is larger than the threshold (No in S360), the control unit 10 does not have a record of the same vehicle as the transmission source vehicle of the communication packet received this time in the surrounding vehicle list. Based on the content of the received communication packet, a new record is generated and registered in the surrounding vehicle list (S365).

  In the new record, the packet number and each value Xr, Vr, Dr, δVr, Tr are described based on the content of the received communication packet in the same manner as the processing in S375. However, in S365, the value 0 is described as the dangerous vehicle flag in the new record. In this way, when the processing in S365 is completed, the control unit 10 proceeds to S380.

  When the process proceeds to S380, the control unit 10 determines whether or not the packet transmission source vehicle is determined to be “high risk” in the first half step (see S260 and S270) in the dangerous vehicle setting process. If it is determined that it is determined to be “large” (Yes in S380), dangerous vehicle setting is performed on the record registered or updated this time (S390).

  That is, the dangerous vehicle flag of the record registered in S365 or the record updated in S375 is set to the value 1, and the dangerous vehicle flags of all the records in the surrounding vehicle list excluding this record are reset to the value 0 (S390). In this way, in S390, one of the vehicles around the host vehicle is set as a dangerous vehicle.

  When the dangerous vehicle is set, the control unit 10 proceeds to S395 and inputs the dangerous vehicle update notification to the power cycle switching processing task (see FIG. 7) described later to notify that the dangerous vehicle has been updated. To do. Thereafter, the update setting process ends.

  On the other hand, when the control unit 10 determines that the packet transmission source vehicle is determined to be “low risk” (No in S380), the control unit 10 updates the dangerous vehicle without executing the processes of S390 and S395. The update setting process ends.

  In addition, when the update setting process is ended in S280 in this way, the control unit 10 once ends the dangerous vehicle setting process and repeats the same process from S210 again. And in the period which has not received the communication packet from the radio | wireless communication apparatus of another vehicle (it is No at S210), the operation | movement which performs the process at the time of non-reception shown in FIG. 6 is repeated in S290. FIG. 6 is a flowchart showing non-reception processing executed by the control unit 10.

  When the non-reception process shown in FIG. 6 is started, the control unit 10 records a record in which a predetermined time has elapsed since the last update based on the time stamp Tr of each record registered in the surrounding vehicle list. It is deleted from the surrounding vehicle list as having left the communication range. Specifically, a record in which the time obtained by subtracting the time indicated by the time stamp Tr from the current time exceeds a predetermined time is deleted from the surrounding vehicle list (S291).

  When this process is finished, the control unit 10 determines whether or not the dangerous vehicle has left the communication range (S293). Specifically, in S291, it is determined whether or not the dangerous vehicle has left by determining whether or not the record in which the dangerous vehicle flag is set to 1 is deleted.

  If it is determined in S293 that the dangerous vehicle has not left, the control unit 10 ends the non-reception process without executing the processes of S295 to S299. On the other hand, if it is determined in S293 that the dangerous vehicle has left, it is determined whether or not the surrounding vehicle list is in an empty state in which no record is registered (S295). If it is determined that the surrounding vehicle list is empty (Yes in S295), the process proceeds to S299, and in order to notify that there is no dangerous vehicle set, the power cycle described later is performed in the same manner as in S395. A dangerous vehicle update notification is input to the switching process task to notify that the dangerous vehicle has been updated. Thereafter, the non-reception process is terminated.

  On the other hand, if it is determined that the surrounding vehicle list is not empty (No in S295), the control unit 10 proceeds to S297, and among the record groups registered in the surrounding vehicle list, the relative speed evaluation value δVr. The record with the largest is set as a dangerous vehicle. That is, the dangerous vehicle flag of the record having the maximum relative speed evaluation value δVr in the record group registered in the surrounding vehicle list is set to the value 1. Then, it transfers to S299, inputs a dangerous vehicle update notification to a power cycle switching process task, and complete | finishes the said non-reception process.

  Next, processing (FIG. 7) realized by the above-described power cycle switching processing task will be described. FIG. 7 is a flowchart showing the power cycle switching process executed by the control unit 10. The controller 10 executes this power cycle switching process immediately after the wireless communication device 1 is activated.

  When the power cycle switching process is started, the control unit 10 sets default values recorded in a built-in ROM (not shown) as the transmission cycle and transmission power in the communication unit 20 (specifically, the transmission unit 21). Then, the communication unit 20 is initialized. In this way, the control unit 10 causes the transmission unit 21 to transmit the communication packet with the default transmission cycle and transmission power (S410).

  When this process is finished, the control unit 10 proceeds to S420 and waits until a dangerous vehicle update notification is input by the processes of S299 and S395 from the dangerous vehicle setting process task. When the dangerous vehicle update notification is input (Yes in S420), the process proceeds to S430, and the dangerous vehicle is referred to by the same method as S230 by referring to the dangerous vehicle flag of each record registered in the surrounding vehicle list. It is determined whether or not is set.

  If it is determined that a dangerous vehicle is set (Yes in S430), the transmission power of the transmission unit 21 corresponds to the relative distance Dr indicated by the record of the dangerous vehicle according to the transmission power setting map recorded in the built-in ROM. The updated value is updated (S440). FIG. 8A is a conceptual diagram of a transmission power setting map recorded in the ROM.

  The control unit 10 of this embodiment stores a transmission power setting map indicating the correspondence between the relative distance D and the transmission power to be set in the built-in ROM. In this transmission power setting map, as shown in FIG. 8A, the correspondence relationship between the relative distance and the transmission power is set so that the transmission power increases as the relative distance increases. In S440, according to this transmission power setting map, the transmission power is set higher in the transmission unit 21 as the relative distance is larger (longer).

  When this process is completed, the control unit 10 proceeds to S450, and the relative speed evaluation value δVr indicated by the dangerous vehicle record indicates the transmission cycle of the transmission unit 21 according to the transmission cycle setting map recorded in the built-in ROM. Update to a value corresponding to. FIG. 8B is a conceptual diagram of a transmission cycle setting map recorded in the ROM.

  As shown in FIG. 8B, the control unit 10 of the present embodiment stores a transmission cycle setting map indicating the correspondence between the relative velocity vector absolute value δV and the transmission cycle to be set in the ROM. Specifically, in this transmission cycle setting map, the correspondence relationship between the relative velocity vector absolute value and the transmission cycle is set so that the transmission cycle becomes shorter as the relative velocity vector absolute value increases.

  That is, in S450, based on the relative speed vector absolute value δV as the relative speed evaluation value δVr indicated by the dangerous vehicle record, the control unit 10 sets a shorter transmission cycle as the relative speed vector absolute value δV increases. Set to.

  In this way, when the dangerous vehicle is changed, the control unit 10 sets the transmission power and the transmission cycle to values corresponding to the changed motion state of the dangerous vehicle, and thereafter the set transmission power and transmission cycle. Thus, the communication packet is transmitted from the transmission unit 21.

  When the transmission power and the transmission cycle are set (S440, S450), the control unit 10 proceeds to S420 and waits until a new dangerous vehicle update notification is input. When a new dangerous vehicle update notification is input, the process proceeds to S430 again, and the subsequent process is executed.

  On the other hand, if it is determined in S430 that a dangerous vehicle is not set (No in S430), the control unit 10 proceeds to S460 and sets the above-described default value as transmission power in the transmission unit 21. Similarly, a default value is set for the transmission cycle (S470). In this way, when the dangerous vehicle is not set, the control unit 10 transmits the communication packet from the transmission unit 21 with the default transmission power and transmission cycle.

  When the transmission power and the transmission cycle are set to default values in this way (S460, S470), the control unit 10 proceeds to S420, waits until a new dangerous vehicle update notification is input, and newly updates the dangerous vehicle. When the notification is input, the process proceeds to S430 again, and subsequent processing is executed.

  The configuration of the wireless communication device 1 according to the first embodiment has been described above. In the wireless communication device 1, the magnitude (absolute value) δV of the relative speed vector with respect to the own vehicle is used. As shown in FIG. 9, when there are a plurality of vehicles A1, A2, A3, A4, A5, A6, the vehicle A6 having the maximum value δV (value δVr) is evaluated. A dangerous vehicle is set, and a communication packet is transmitted with transmission power corresponding to the relative distance D from the dangerous vehicle. Further, the communication packet is transmitted in a shorter transmission cycle as the relative speed vector absolute value δV of the dangerous vehicle is larger.

  Therefore, according to this wireless communication device 1, it is possible to transmit a communication packet loaded with vehicle information of the own vehicle with transmission power sufficient to inform the dangerous vehicle of the existence of the own vehicle. A collision between the vehicle and another vehicle can be avoided with high probability. Also, according to the wireless communication device 1, the more dangerous vehicles move with respect to the host vehicle, the shorter the cycle, the more communication packets are transmitted. Vehicle information can be transmitted.

  That is, if the vehicle information is transmitted with a long transmission cycle even though the dangerous vehicle is approaching the host vehicle at high speed, the presence of the host vehicle cannot be quickly transmitted to the dangerous vehicle. However, according to this embodiment, the communication packet is transmitted at a transmission cycle corresponding to the relative speed with the dangerous vehicle. Thus, it is possible to avoid collision between vehicles with high probability.

  In addition, according to the present embodiment, since communication packets are transmitted with a transmission power and a transmission cycle that are necessary and sufficient for collision avoidance, when the vehicle density is high, communication interference between vehicles becomes intense and normally between vehicles. It is possible to prevent as much as possible that communication cannot be performed and vehicle information necessary for collision avoidance cannot be exchanged. Therefore, if a vehicle-to-vehicle communication system is configured using the wireless communication device 1, communication for collision avoidance can be appropriately performed between vehicles regardless of the vehicle density or the like.

  Then, the radio | wireless communication apparatus 1 of 2nd Example is demonstrated. However, the wireless communication device 1 according to the second embodiment is different from the first embodiment in the contents of the dangerous vehicle setting process, and the other configurations are the same as those in the first embodiment. As an explanation of the second embodiment, the contents of the dangerous vehicle setting process executed by the control unit 10 will be selectively explained.

FIG. 10 is a flowchart showing the dangerous vehicle setting process repeatedly executed by the control unit 10 in the wireless communication device 1 of the second embodiment.
When the dangerous vehicle setting process shown in FIG. 10 is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet from the outside (S510), and determines that it has not received a communication packet (S510). No), the process proceeds to S590, and the above non-reception process is executed. Thereafter, the dangerous vehicle setting process is temporarily terminated.

  In contrast, if it is determined that the communication packet has been received (Yes in S510), the control unit 10 proceeds to S520, where the position coordinates of the host vehicle obtained from the state detector 57 and the packet transmission described in the received packet are transmitted. Based on the position coordinates of the original vehicle, the relative distance D of the packet transmission source vehicle with respect to the own vehicle is calculated. When the calculation of the relative distance D is completed, the process proceeds to S521, where it is determined whether or not the relative distance D is equal to or less than a predetermined threshold, and when the relative distance D is equal to or less than the threshold (in S521). Yes), the process proceeds to S523.

  On the other hand, if it is determined that the relative distance D is greater than the threshold (No in S521), the control unit 10 proceeds to S525, and makes a list registration prohibition determination to prohibit record registration and record update in the surrounding vehicle list. . Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the host vehicle (S570), and the process proceeds to S575.

  In S523, the control unit 10 uses the own vehicle as a reference based on the speed vector of the own vehicle obtained from the state detector 57 and the speed vector of the packet transmission source vehicle described in the received packet. The absolute value δV of the relative speed vector of the packet transmission source vehicle is calculated, and then the process proceeds to S530.

  In S530, the control unit 10 determines whether or not a dangerous vehicle is currently set by referring to the dangerous vehicle flag of each record registered in the surrounding vehicle list. If it is determined that no dangerous vehicle is set (No in S530), the process proceeds to S560, and it is determined that the packet transmission source vehicle is “high risk” with respect to the own vehicle.

  On the other hand, when determining that a dangerous vehicle is set (Yes in S530), the control unit 10 determines the value δVr indicated by each record registered in the surrounding vehicle list and the value δV obtained in S523 based on the received packet this time. (S540), it is determined whether the value δV obtained in S523 is larger than any of the values δVr indicated by the records registered in the surrounding vehicle list (S550).

  Then, if it is determined that the value δV obtained in S523 is greater than any of the values δVr indicated by the records registered in the surrounding vehicle list (Yes in S550), the process proceeds to S560, and the packet transmission source vehicle becomes the own vehicle. On the other hand, it is determined that the degree of danger is high. Thereafter, the process proceeds to S575.

  On the other hand, when it is determined that the relative velocity vector absolute value δV of the packet transmission source vehicle obtained in S523 is the same as or smaller than any of the values δVr indicated by the records registered in the surrounding vehicle list (No in S550). The control unit 10 determines that the packet transmission source vehicle is “low risk” with respect to the own vehicle (S570), and then proceeds to S575.

  In S575, the control unit 10 determines whether the list registration prohibition determination is made. If the list prohibition determination is not made (No in S575), the update setting described above is performed in S580. After executing the process, the dangerous vehicle setting process is temporarily ended.

  On the other hand, if it is determined that the list prohibition determination is made (Yes in S575), the control unit 10 temporarily ends the dangerous vehicle setting process without executing the process of S580. That is, in this embodiment, when the relative distance D is equal to or smaller than the threshold value, the degree of risk is evaluated in S540 and the update setting process is executed in S580. However, if the relative distance D exceeds the threshold value, the process proceeds to S540. If the risk is not evaluated, the dangerous vehicle setting process is temporarily terminated without executing the update setting process in S580.

  In this way, in this embodiment, for packet transmission source vehicles whose relative distance D exceeds the threshold value, the packet transmission source vehicle record is not registered in the surrounding vehicle list, and this packet transmission source vehicle is designated as a dangerous vehicle. Do not set to.

  As described above, the second embodiment has been described. According to the second embodiment, the risk level is maximum (in other words, δV is maximum) in the vehicle group existing within a predetermined distance with respect to the own vehicle. Since the vehicle is set as a dangerous vehicle, it is possible to set the dangerous vehicle more appropriately than the first embodiment and to set the transmission conditions (transmission power and transmission cycle) more appropriately from the viewpoint of collision avoidance.

  That is, according to the second embodiment, the dangerous vehicle is appropriately identified and the transmission condition is set according to the dangerous vehicle, so that communication can be performed effectively using communication resources. In addition, the vehicle information necessary for collision avoidance can be exchanged between vehicles efficiently and appropriately while suppressing communication interference.

  Then, the radio | wireless communication apparatus 1 of 3rd Example is demonstrated. However, in the wireless communication device 1 of the third embodiment, the contents of the dangerous vehicle setting process are different from those of the first embodiment, and the other configurations are the same as those of the first embodiment. As a description of the wireless communication device 1 of the third embodiment, the contents of the dangerous vehicle setting process executed by the control unit 10 will be selectively described.

  FIG. 11 is a flowchart showing a dangerous vehicle setting process repeatedly executed by the control unit 10 of the wireless communication device 1 in the third embodiment. When the dangerous vehicle setting process shown in FIG. 11 is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S610), and determines that it has not received a communication packet (No in S610). ), The process proceeds to S690, and after executing the above non-reception process, the dangerous vehicle setting process is temporarily ended.

  On the other hand, if it is determined that the communication packet has been received (Yes in S610), the control unit 10 automatically determines based on the position coordinates of the own vehicle obtained from the state detector 57 and the contents of the map database 51 of the navigation device 50. A travel road of the vehicle (for example, a link ID of the travel road) is specified (S620).

  Similarly, the control unit 10 specifies the traveling road (link ID) of the transmission source vehicle based on the position coordinates of the transmission source vehicle indicated by the received communication packet and the contents of the map database 51 of the navigation device 50 (S621). ).

  Further, when the traveling roads of the own vehicle and the packet transmission source vehicle are specified, the control unit 10 travels on the same road as the own vehicle or a road intersecting with the own vehicle based on the information on the identified traveling road. It is determined whether or not (S623). In other words, it is determined whether the packet transmission source vehicle is traveling on the same road as the host vehicle or another road that is connected to the road and can enter the road. Specifically, for example, whether the link on which the packet transmission source vehicle is traveling is the same link as the link on which the host vehicle is traveling, or a link connected to the link on which the host vehicle is traveling. to decide.

  If it is determined that the packet transmission source vehicle is traveling on the same road as the own vehicle or a road that intersects with the same (Yes in S623), the process proceeds to S627. On the other hand, if it is determined that the packet transmission source vehicle is not traveling on the same road as the own vehicle or a road intersecting with the own vehicle (No in S623), the process proceeds to S625, and record registration and record update in the surrounding vehicle list are performed. Make a list registration prohibition judgment to prohibit. Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the host vehicle (S670), and the process proceeds to S675.

  Further, when the process proceeds to S627, the control unit 10 based on the position coordinates and speed vector of the host vehicle obtained from the state detector 57 and the position coordinates and speed vector of the packet transmission source vehicle described in the received packet, The relative distance D and the relative velocity vector absolute value δV of the packet transmission source vehicle with respect to the own vehicle are calculated. Thereafter, the process proceeds to S630.

  In S630, the control unit 10 refers to the dangerous vehicle flag of each record registered in the surrounding vehicle list to determine whether or not the dangerous vehicle is currently set, and the dangerous vehicle is set. If it is determined that there is no (No in S630), the process proceeds to S660, where it is determined that the packet transmission source vehicle is “high risk” with respect to the host vehicle. Thereafter, the process proceeds to S675.

  On the other hand, if it is determined that a dangerous vehicle is set (Yes in S630), the control unit 10 uses the relative velocity vector absolute value δV calculated in S627, and in S640 to S670, S540 to S570 of the second embodiment. The same processing is executed. Thereafter, the process proceeds to S675.

  When the process proceeds to S675, the control unit 10 determines whether or not the list registration prohibition determination (see S625) is made. If the list prohibition determination is not made (No in S675), the control unit 10 proceeds to S680. After executing the above update setting process, the dangerous vehicle setting process is temporarily ended.

On the other hand, if it is determined that the list prohibition determination has been made (Yes in S675), the dangerous vehicle setting process is temporarily terminated without executing the process of S680.
In this way, in this embodiment, the risk assessment (processing of S640) is not performed for a vehicle that is not on any of the same road as the own vehicle and a road that intersects with the own vehicle. Do not register in the surrounding vehicle list, and do not set the vehicle as a dangerous vehicle.

  As described above, the third embodiment has been described. According to the third embodiment, the degree of risk is maximum (in other words, the vehicle group traveling on the same road as the road on which the host vehicle is traveling or a road intersecting with the same). , ΔV is maximum) is set as a dangerous vehicle. From the viewpoint of collision avoidance, the dangerous vehicle is set more appropriately than the first embodiment, and transmission conditions (transmission power and transmission cycle) are set. be able to. That is, according to the third embodiment, it is possible to set a dangerous vehicle more appropriately than the first embodiment, and to set a transmission condition according to this dangerous vehicle, to suppress communication interference and to improve efficiency. And appropriately, vehicle information required for collision avoidance can be exchanged between vehicles.

  Next, the wireless communication device 1 according to the fourth embodiment will be described. However, in the wireless communication device 1 of the fourth embodiment, the contents of the dangerous vehicle setting process are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. As an explanation of the fourth embodiment, the contents of the dangerous vehicle setting process executed by the control unit 10 will be selectively explained.

FIG. 12A is a flowchart showing a dangerous vehicle setting process that is repeatedly executed by the control unit 10 in the wireless communication device 1 according to the fourth embodiment.
When the dangerous vehicle setting process shown in FIG. 12A is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S710), and determines that the communication packet has not been received (S710). No in S710), the process proceeds to S790, and after executing the above non-reception process, the dangerous vehicle setting process is temporarily terminated.

  On the other hand, when determining that the communication packet has been received (Yes in S710), the control unit 10 proceeds to S720, and transmits the position coordinates of the own vehicle obtained from the state detector 57 and the packet transmission described in the received packet. Based on the position coordinates of the original vehicle, it is determined whether or not another vehicle exists in a region R between the location of the own vehicle and the location of the packet transmission source vehicle.

  FIG. 12B is an explanatory diagram showing the region R. That is, in S720, a region having a predetermined width around the straight line connecting the host vehicle and the packet transmission source vehicle is defined as the region R. And when the record in which the position coordinate Xr of this area | region R was described exists in a periphery vehicle list | wrist, it judges that another vehicle exists in the area | region R between the own vehicle and a packet transmission origin vehicle, When the record in which the position coordinate Xr in the region R is written does not exist in the neighboring vehicle list, it is determined that there is no other vehicle in the region R between the own vehicle and the packet transmission source vehicle.

  However, since there is a possibility that a record of the same vehicle as the packet transmission source vehicle is registered in the surrounding vehicle list, a record in which the position coordinate Xr in this region R is recorded exists in the surrounding vehicle list The packet number PN of each corresponding record is compared with the packet number PN0 indicated by the communication packet received this time, and for each corresponding record, the packet number PN is larger than the value (PN0-α). It is determined whether or not it is in a smaller range (PN0> PN> PN0-α), and when the packet numbers PN of all corresponding records are within the above range, the host vehicle and the packet transmission source vehicle are exceptional. It is determined that there is no other vehicle in the region R between.

  That is, only when the record indicating the packet number outside the above range (PN0> PN> PN0-α) and indicating the position coordinate Xr in the region R exists in the surrounding vehicle list, the host vehicle and the packet transmission source vehicle It is determined that there is another vehicle in the region R between.

  In this embodiment, the region R is defined as a rectangular region centered on a straight line connecting the host vehicle and the packet transmission source vehicle, but the region R is located between the host vehicle and the packet transmission source vehicle. It may be defined according to the shape of the road.

  If it is determined that there is another vehicle in the region R between the host vehicle and the packet transmission source vehicle (Yes in S720), the control unit 10 proceeds to S725 and makes a list registration prohibition determination. Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the host vehicle (S770), and the process proceeds to S775.

  On the other hand, if it is determined that there is no other vehicle in the region R between the host vehicle and the packet transmission source vehicle (No in S720), the control unit 10 proceeds to S723 and the host vehicle obtained from the state detector 57 , And the relative distance D and relative velocity vector absolute value δV of the packet transmission source vehicle with reference to the own vehicle based on the position coordinate and velocity vector of Is calculated. Thereafter, the process proceeds to S730.

  In S730, the control unit 10 determines whether a dangerous vehicle is currently set by referring to the dangerous vehicle flag of each record registered in the surrounding vehicle list. If it is determined that no dangerous vehicle is set (No in S730), the process proceeds to S760, where it is determined that the packet transmission source vehicle is “high risk” with respect to the own vehicle. Thereafter, the process proceeds to S775.

  On the other hand, if it is determined that a dangerous vehicle is set (Yes in S730), the control unit 10 uses the relative velocity vector absolute value δV calculated in S723, and in S740 to S770, S540 to S570 of the second embodiment. The same processing is executed. Thereafter, the process proceeds to S775.

  In S775, the control unit 10 determines whether the list registration prohibition determination (see S725) is made. If the list prohibition determination is not made (No in S775), the control unit 10 determines in S780. After executing the above update setting process, the dangerous vehicle setting process is temporarily ended. On the other hand, when determining that the list prohibition determination has been made (Yes in S775), the control unit 10 temporarily ends the dangerous vehicle setting process without executing the process of S780.

  In this way, in the present embodiment, when there is another vehicle between the packet transmission source vehicle and the host vehicle, the packet transmission source vehicle is not registered in the surrounding vehicle list, and this packet transmission source Do not set the vehicle as a dangerous vehicle.

  As described above, the fourth embodiment has been described. According to the fourth embodiment, the degree of risk is increased in the adjacent vehicle group in which no other vehicle exists between the surrounding vehicle groups and the own vehicle. Since the maximum (δV is the maximum) vehicle is set as a dangerous vehicle, a plurality of vehicles near the rear end of the traffic congestion may make the same distant vehicle approaching from behind the traffic congestion row a dangerous vehicle. Thus, it is possible to prevent the occurrence of intense communication interference and the inability to smoothly transmit vehicle information to the dangerous vehicle. Therefore, vehicle information necessary for collision avoidance can be exchanged between vehicles efficiently and appropriately.

  Next, the wireless communication device 1 according to the fifth embodiment will be described. However, in the wireless communication device 1 of the fifth embodiment, the contents of the dangerous vehicle setting process are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. As an explanation of the fifth embodiment, the contents of the dangerous vehicle setting process executed by the control unit 10 will be selectively explained.

FIG. 13 is a flowchart showing a dangerous vehicle setting process repeatedly executed by the control unit 10 in the wireless communication device 1 of the fifth embodiment.
When the dangerous vehicle setting process shown in FIG. 13 is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S810), and determines that it has not received a communication packet (No in S810). ), The process proceeds to S890, and after executing the above non-reception process, the dangerous vehicle setting process is temporarily terminated.

  In contrast, if it is determined that a communication packet has been received (Yes in S810), the control unit 10 proceeds to S820, and the speed vector Vs of the host vehicle obtained from the state detector 57 and the packet described in the received packet Based on the speed vector V of the transmission source vehicle, a relative speed vector Vp = V−Vs of the packet transmission source vehicle based on the own vehicle is calculated.

  When this process is completed, the control unit 10 determines the presence of the packet transmission source vehicle based on the position coordinate Xs of the own vehicle obtained from the state detector 57 and the position coordinate X of the packet transmission source vehicle described in the received packet. The angle θ (0 ≦ θ ≦ π) formed by the relative velocity vector Vp is calculated with respect to the vector Q = Xs−X having the point Pa as the starting point and the own vehicle existing point Pb as the end point (S821). FIG. 14 is an explanatory diagram showing the definition of the angle θ.

  Then, it is determined whether or not the angle θ is equal to or smaller than a predetermined threshold value (S823). If it is determined that the angle θ exceeds the threshold value (No in S823), the process proceeds to S825 and the list registration prohibition determination is performed. Down. Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the host vehicle (S870), and the process proceeds to S875.

  On the other hand, if it is determined that the angle θ is equal to or smaller than a predetermined threshold value (Yes in S823), the control unit 10 proceeds to S827 and receives the position coordinates and speed vector of the host vehicle obtained from the state detector 57, and the reception. Based on the position coordinates and speed vector of the packet transmission source vehicle described in the packet, the relative distance D and the relative velocity vector absolute value δV of the packet transmission source vehicle with respect to the own vehicle are calculated. Thereafter, the process proceeds to S830.

  When the process proceeds to S830, the control unit 10 determines whether or not a dangerous vehicle is currently set. If the control unit 10 determines that a dangerous vehicle is not set (No in S830), the control unit 10 proceeds to S860 and transmits the packet. It is determined that the transmission source vehicle is “high risk” with respect to the host vehicle. Thereafter, the process proceeds to S875.

  On the other hand, if it is determined that a dangerous vehicle is set (Yes in S830), the control unit 10 uses the relative velocity vector absolute value δV calculated in S827, and in S840 to S870, S540 to S570 of the second embodiment are obtained. A similar process is executed. Thereafter, the process proceeds to S875.

  In S875, the control unit 10 determines whether the list registration prohibition determination (see S825) has been made. If the list prohibition determination has not been made (No in S875), the control unit 10 determines in S880. After executing the above update setting process, the dangerous vehicle setting process is temporarily ended. On the other hand, if it is determined that the list prohibition determination has been made (Yes in S875), the dangerous vehicle setting process is temporarily terminated without executing the process of S880.

  In this way, in this embodiment, the relative speed vector Vp of the packet transmission source vehicle with reference to the own vehicle, and the vector Q having the existence point Pa of the packet transmission source vehicle as the start point and the existence point Pb of the own vehicle as the end point. If the angle θ with the angle exceeds the threshold value, it is determined that there is no danger of collision, so that the record of the packet transmission source vehicle is not registered in the surrounding vehicle list, and the packet transmission source vehicle is set as the dangerous vehicle. Do not.

  Although the fifth embodiment has been described above, according to the fifth embodiment, a vehicle having a maximum risk (δV is maximum) is set as a dangerous vehicle in the vehicle group in which the angle θ is equal to or less than a threshold value. Therefore, from the viewpoint of collision avoidance, it is possible to set the dangerous vehicle more appropriately than the first embodiment and set the transmission conditions (transmission power and transmission cycle). Therefore, according to the fifth embodiment, vehicle information necessary for collision avoidance can be exchanged between vehicles more efficiently and appropriately with less communication interference than in the first embodiment.

  Next, the wireless communication device 1 according to the sixth embodiment will be described. However, in the wireless communication device 1 of the sixth embodiment, the contents of the dangerous vehicle setting process and the power cycle switching process are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. Since they are the same, here, as an explanation of the sixth embodiment, the contents of the dangerous vehicle setting process executed by the control unit 10 and the contents of the power cycle switching process will be selectively explained.

FIG. 15A is a flowchart showing a dangerous vehicle setting process repeatedly executed by the control unit 10 in the wireless communication device 1 of the sixth embodiment.
When the dangerous vehicle setting process shown in FIG. 15A is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S910), and determines that the communication packet has not been received (S910). No in S910), the process proceeds to S990, and after executing the above non-reception process, the dangerous vehicle setting process is temporarily ended.

  On the other hand, if it is determined that the communication packet has been received (Yes in S910), the control unit 10 proceeds to S920, where the position coordinate Xs of the host vehicle obtained from the state detector 57, the speed vector Vs, and the received packet are included. Based on the position coordinates X and the velocity vector V of the packet transmission source vehicle described, from the relative velocity vector Vp = V−Vs of the packet transmission source vehicle with reference to the own vehicle and the location Pa of the packet transmission source vehicle The vehicle direction speed component δVe of the packet transmission source vehicle expressed by the inner product of the unit vector E of the vector Q = Xs−X extending in the direction Pb of the own vehicle is calculated (δVe = Vp · E). FIG. 16 is an explanatory diagram showing the own vehicle direction speed component δVe of the packet transmission source vehicle.

  When this process is finished, the control unit 10 determines whether or not the packet transmission source vehicle is moving in a direction away from the host vehicle (S921). Specifically, it is determined whether or not δVe is a negative value (δVe <0).

  If it is determined that the packet transmission source vehicle is moving in the direction away from the host vehicle (Yes in S921), the control unit 10 proceeds to S925 and makes a list registration prohibition determination. Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the own vehicle (S970), and the process proceeds to S975.

  On the other hand, if it is determined that the packet transmission source vehicle has not moved in the direction away from the own vehicle (No in S921), the control unit 10 proceeds to S927, and the position coordinate Xs of the own vehicle obtained from the state detector 57 is obtained. Based on the position coordinates X of the packet transmission source vehicle described in the received packet, the relative distance D of the packet transmission source vehicle with respect to the own vehicle is calculated. Thereafter, the process proceeds to S930.

  When the process proceeds to S930, the control unit 10 determines whether or not a dangerous vehicle is currently set. If the control unit 10 determines that a dangerous vehicle is not set (No in S930), the control unit 10 proceeds to S960 and transmits the packet. It is determined that the transmission source vehicle is “high risk” with respect to the host vehicle. Thereafter, the process proceeds to S975.

  On the other hand, when determining that the dangerous vehicle is set (Yes in S930), the control unit 10 determines the value δVr indicated by each record registered in the surrounding vehicle list and the value δVe obtained in S920 based on the received packet this time. (S940), it is determined whether the value δVe obtained in S920 is larger than any of the values δVr indicated by the records registered in the surrounding vehicle list (S950).

  However, in this embodiment, in S365 and S375 of the update setting process executed in S980, the own vehicle direction speed component δVe of the packet transmission source vehicle obtained in S920 is described in the record as the relative speed evaluation value δVr. . That is, in S940, the vehicle direction speed component δVe of the vehicle corresponding to the record indicated by each record registered in the surrounding vehicle list is compared with the value δVe obtained in S920 based on the received packet this time (S940). ), It is determined whether or not the value δVe obtained in S920 is larger than any of the values δVr = δVe indicated by the records registered in the surrounding vehicle list (S950).

  When it is determined that the value δVe obtained in S920 is larger than any of the values δVr indicated by the records registered in the surrounding vehicle list (Yes in S950), the process proceeds to S960, and the packet transmission source vehicle becomes the own vehicle. On the other hand, it is determined that the degree of danger is high. Thereafter, the process proceeds to S975.

  On the other hand, if it is determined that the value δVe obtained in S920 is the same as or smaller than any of the values δVr indicated by the records registered in the surrounding vehicle list (No in S950), the control unit 10 It is determined that the vehicle is “low risk” with respect to the host vehicle (S970), and thereafter, the process proceeds to S975.

  In S975, the control unit 10 determines whether the list registration prohibition determination (see S925) is made. If the list prohibition determination is not made (No in S975), the control unit 10 determines in S980. After executing the above update setting process, the dangerous vehicle setting process is temporarily ended. On the other hand, if it is determined that the list prohibition determination has been made (Yes in S975), the control unit 10 temporarily ends the dangerous vehicle setting process without executing the process of S980.

  In this way, in this embodiment, when the packet transmission source vehicle is moving in a direction away from the host vehicle, the packet transmission source vehicle record is not registered in the surrounding vehicle list, and the packet transmission is performed. Do not set the original vehicle as a dangerous vehicle.

  Then, the content of the power cycle switching process which the control part 10 performs is demonstrated. The power cycle switching process executed by the control unit 10 in this embodiment is basically the same as that in the first embodiment (see FIG. 7). However, as described above, in this embodiment, the relative speed evaluation value is used. Since the vehicle direction speed component δVe of the packet transmission source vehicle is registered as δVr in the surrounding vehicle list, in S450 of the power cycle switching process, the transmission cycle of the transmission unit 21 is determined according to the transmission cycle setting map recorded in the built-in ROM. Is updated to a value corresponding to the own vehicle direction speed component δVe of the dangerous vehicle indicated by the record of the dangerous vehicle. FIG. 15B is a conceptual diagram of the processing content of S450 in the present embodiment and the transmission cycle setting map recorded in the ROM of the control unit 10.

  The transmission cycle setting map of the present embodiment shows the correspondence between the own vehicle direction speed component δVe of the dangerous vehicle and the transmission cycle to be set. Specifically, in this transmission cycle setting map, the speed component δVe is The correspondence relationship between the speed component δVe and the transmission cycle is set so that the transmission cycle becomes shorter as it increases.

  That is, in S450, based on the own vehicle direction speed component δVe of the dangerous vehicle as the relative speed evaluation value δVr indicated by the record of the dangerous vehicle, the control unit 10 transmits the shorter the larger the own vehicle direction speed component δVe of the dangerous vehicle. The period is set in the transmission unit 21.

  Although the sixth embodiment has been described above, according to the sixth embodiment, not the absolute value δV of the relative speed vector Vp of the other vehicle based on the own vehicle but the own vehicle direction speed component δVe of the relative speed vector Vp. Based on the above, the risk level of the vehicle is evaluated, and the vehicle having the maximum speed component δVe is set as the risk vehicle as the vehicle having the maximum risk level. A dangerous vehicle can be set to the transmission condition (transmission power and transmission cycle). Therefore, according to the sixth embodiment, vehicle information necessary for collision avoidance can be exchanged between vehicles efficiently and appropriately while suppressing communication interference as compared with the first embodiment.

  Next, the wireless communication apparatus 1 according to the seventh embodiment will be described. However, in the wireless communication device 1 of the seventh embodiment, the contents of the dangerous vehicle setting process and the power cycle switching process are different from those of the first embodiment, and other configurations are the same as those of the first embodiment. Since they are the same, here, as the explanation of the seventh embodiment, the contents of the dangerous vehicle setting process and the power cycle switching process executed by the control unit 10 will be selectively explained.

FIG. 17 is a flowchart showing a dangerous vehicle setting process repeatedly executed by the control unit 10 in the wireless communication device 1 of the seventh embodiment.
When the dangerous vehicle setting process shown in FIG. 17 is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S1010), and determines that it has not received a communication packet (No in S1010). ), The process proceeds to S1090, and after executing the above non-reception process, the dangerous vehicle setting process is temporarily ended.

  In contrast, if it is determined that the communication packet has been received (Yes in S1010), the control unit 10 proceeds to S1020, and the position coordinate Xs and speed vector Vs of the host vehicle obtained from the state detector 57 and the received packet are included. Based on the described position coordinates X and the velocity vector V of the packet transmission source vehicle, the own vehicle direction speed component δVe of the packet transmission source vehicle is calculated in the same manner as the processing in S920 in the sixth embodiment.

  When this processing is finished, the control unit 10 determines whether or not the packet transmission source vehicle may collide with the own vehicle by determining whether or not the packet transmission source vehicle is moving away from the own vehicle. Is determined (S1021). Specifically, it is determined whether or not δVe is a negative value (δVe <0).

  If it is determined that the packet transmission source vehicle is moving in a direction away from the host vehicle (Yes in S1021), the packet transmission source vehicle is determined not to collide with the host vehicle, and the process proceeds to S1025, and list registration is prohibited. Make a decision. Thereafter, it is determined that the packet transmission source vehicle is “low risk” with respect to the own vehicle (S1070), and the process proceeds to S1075.

  On the other hand, if it is determined that the packet transmission source vehicle is not moving in a direction away from the own vehicle (No in S1021), the control unit 10 proceeds to S1027, assuming that the packet transmission source vehicle may collide with the own vehicle. Then, based on the position coordinate Xs of the own vehicle obtained from the state detector 57 and the position coordinate X of the packet transmission source vehicle described in the received packet, the relative distance D of the packet transmission source vehicle with reference to the own vehicle. Is calculated. Thereafter, the process proceeds to S1029.

  In S1029, the control unit 10 divides the relative distance D calculated in S1027 by the value δVe calculated in S1020, and calculates the remaining time C until the packet transmission source vehicle collides with the own vehicle. The collision time C between the transmission source vehicle and the host vehicle is calculated (C = D / δVe). Then, when this process is finished, the process proceeds to S1030.

  When the process proceeds to S1030, the control unit 10 determines whether or not a dangerous vehicle is currently set. If the control unit 10 determines that a dangerous vehicle is not set (No in S1030), the process proceeds to S1060, It is determined that the transmission source vehicle is “high risk” with respect to the host vehicle. Thereafter, the process proceeds to S1075.

  On the other hand, if it is determined that a dangerous vehicle is set (Yes in S1030), the control unit 10 determines, for each record registered in the surrounding vehicle list, the vehicle corresponding to the record from the value δVr and the relative distance D indicated by the record. The collision time Cr = D / δVr is calculated, and the collision time Cr of each record is compared with the collision time C obtained in S1029 based on the received packet this time (S1040). And it is judged whether the collision time C calculated | required by S1029 is smaller than any of the collision time Cr of each record registered into the surrounding vehicle list | wrist (S1050).

  If it is determined that the collision time C obtained in S1029 is shorter than any of the collision times Cr of each record registered in the surrounding vehicle list (Yes in S1050), the process proceeds to S1060, and the packet transmission source vehicle is the own vehicle. Is determined to be “high risk”. Thereafter, the process proceeds to S1075.

  On the other hand, if it is determined that the collision time C obtained in S1029 is the same as or greater than any of the collision times Cr of each record registered in the surrounding vehicle list (No in S1050), the control unit 10 transmits the packet. It is determined that the original vehicle is “low risk” with respect to the host vehicle (S1070), and thereafter, the process proceeds to S1075.

  In S1075, the control unit 10 determines whether the list registration prohibition determination (see S1025) is made. If the list prohibition determination is not made (No in S1075), in S1080. After executing the update setting process similar to that of the sixth embodiment, the dangerous vehicle setting process is temporarily ended. On the other hand, if it is determined that the list prohibition determination has been made (Yes in S1075), the control unit 10 temporarily ends the dangerous vehicle setting process without executing the process of S1080.

  In this way, in this embodiment, when the collision time C between the packet transmission source vehicle and the host vehicle is shorter than the collision time Cr with another vehicle, the packet transmission source vehicle is designated as a dangerous vehicle by the update setting process. In the power cycle switching process, the transmission power and the transmission cycle are set according to the motion state of the dangerous vehicle.

  Then, the content of the power cycle switching process which the control part 10 performs in a present Example is demonstrated. The power cycle switching process executed by the control unit 10 in this embodiment is basically the same as that in the first embodiment (see FIG. 7), but in S450, as shown in FIG. The transmission cycle is set to a cycle corresponding to the collision time Cr with the vehicle. FIG. 18 is a conceptual diagram of the processing content of S450 and the transmission cycle setting map recorded in the ROM of the control unit 10 in the present embodiment.

  The transmission cycle setting map of the present embodiment shows the correspondence between the collision time Cr between the dangerous vehicle and the host vehicle and the transmission cycle to be set. Specifically, in this transmission cycle setting map, the collision time Cr The correspondence between the collision time Cr and the transmission period is set so that the transmission period becomes longer as the transmission period becomes longer.

  That is, in S450, the control unit 10 calculates the collision time Cr = Dr / δVr between the dangerous vehicle and the host vehicle from the relative distance Dr and the relative speed evaluation value δVr indicated by the record of the dangerous vehicle. Based on this, a shorter transmission cycle is set in the transmission unit 21 as the collision time Cr is shorter.

  Although the seventh embodiment has been described above, according to the seventh embodiment, the risk level of the vehicle is evaluated based on the collision time Cr with the host vehicle, and the vehicle having the minimum collision time Cr is the vehicle having the highest risk level. Therefore, from the viewpoint of collision avoidance, it is possible to set the transmission condition (transmission power and transmission cycle) more appropriately than the first embodiment from the viewpoint of collision avoidance.

  In particular, in this embodiment, in a situation where a collision is imminent, vehicle information is transmitted in a short cycle so that the presence of the host vehicle is informed to the surrounding vehicles. Vehicle information can be transmitted, and the vehicle information necessary for collision avoidance can be exchanged between vehicles efficiently and appropriately while suppressing communication interference.

  Then, the radio | wireless communication apparatus 1 of 8th Example is demonstrated. However, since the wireless communication device 1 of the eighth embodiment is a part of the wireless communication device 1 of the first embodiment with a partial change, the following description will be given as a description of the eighth embodiment. A configuration different from the wireless communication device 1 according to the embodiment will be described selectively.

  First, in the wireless communication device 1 according to the present embodiment, in the transmission unit 21, the position coordinates and speed of the dangerous vehicle currently set in the own vehicle together with the position information of the own vehicle and the vehicle information indicating the speed vector of the own vehicle. A communication packet storing dangerous vehicle information representing a vector is generated, and this is transmitted at a transmission power and a transmission period set in advance by a power cycle switching process.

  FIG. 19 is an explanatory diagram illustrating a configuration of a communication packet generated by the transmission unit 21 according to the present embodiment. As shown in FIG. 2A, the communication packet generated by the transmission unit 21 and transmitted / received between the vehicles includes header information indicating the packet number, vehicle information indicating the position coordinates of the host vehicle, and the speed vector of the host vehicle. And dangerous vehicle information indicating the position coordinates and speed vector of the dangerous vehicle set by the control unit 10 of the own device. In S120 of the packet transmission process shown in FIG. 2B, the transmission unit 21 is set with the latest position coordinates and speed vector of the host vehicle input from the control unit 10 and the current setting input from the control unit 10. A communication packet having the above-described configuration is generated based on the position coordinates and speed vector of the dangerous vehicle that is present, and broadcasted to the outside as a radio signal at a preset transmission cycle and transmission power. When a dangerous vehicle is not set, the transmission unit 21 generates a communication packet storing information indicating that no dangerous vehicle is set as dangerous vehicle information, and broadcasts the communication packet to the outside as a radio signal.

  Further, the control unit 10 according to the present embodiment is based on the communication packet having the configuration shown in FIG. 19 transmitted from the same type of wireless communication device mounted on another vehicle around the host vehicle via the receiving unit 25. 20 is configured to execute the dangerous vehicle setting process shown in FIG. FIG. 20 is a flowchart illustrating a dangerous vehicle setting process that is repeatedly executed by the control unit 10 in the wireless communication apparatus 1 according to the eighth embodiment, instead of the dangerous vehicle setting process illustrated in FIG. 3.

  When the dangerous vehicle setting process shown in FIG. 20 is started, the control unit 10 determines whether or not the receiving unit 25 has received a communication packet (S1110), and determines that it has not received a communication packet (No in S1110). ), The process proceeds to S1190, the same non-reception process as in the first embodiment is executed, and then the dangerous vehicle setting process is temporarily ended.

  In contrast, if it is determined that a communication packet has been received (Yes in S1110), the control unit 10 proceeds to S1120, and the position coordinate Xs and speed vector Vs of the host vehicle obtained from the state detector 57 and the received packet are included. Based on the position coordinates X and the velocity vector V of the packet transmission source vehicle described as the vehicle information, the relative distance D and the relative velocity vector absolute value δV of the packet transmission source vehicle based on the own vehicle are calculated.

  When the calculation of the values D and δV is completed, the process proceeds to S1125, and the vehicle's position coordinate Xs and speed vector Vs, and the dangerous vehicle (hereinafter referred to as the dangerous vehicle on the packet transmission source vehicle side described as dangerous vehicle information in the received packet). The relative distance Dd = | Xd−Xs | of the transmission source dangerous vehicle with respect to the own vehicle and the absolute value of the relative velocity vector based on the position coordinates Xd and the velocity vector Vd of “transmission source dangerous vehicle”. δVd = | Vd−Vs | is calculated.

  When this process is finished, the control unit 10 proceeds to S1130 and determines whether or not a dangerous vehicle is currently set by referring to the dangerous vehicle flag of each record registered in the surrounding vehicle list. To do. If it is determined that a dangerous vehicle is not set (No in S1130), the process proceeds to S1160, where it is determined that the packet transmission source vehicle is “high risk” with respect to the host vehicle.

  On the other hand, when determining that a dangerous vehicle is set (Yes in S1130), the control unit 10 determines the value δVr indicated by each record registered in the surrounding vehicle list and the value δV obtained in S1120 based on the received packet this time. (S1140), it is determined whether the value δV obtained in S1120 is larger than any of the values δVr indicated by the records registered in the surrounding vehicle list (S1150).

  As will be described in detail later, the wireless communication device 1 according to the present embodiment registers a record about the transmission source dangerous vehicle in the surrounding vehicle list based on the dangerous vehicle information indicated by the received communication packet. That is, in the surrounding vehicle list provided in the wireless communication device 1 of the present embodiment, not only a record about a vehicle that can communicate with the own vehicle, but also a vehicle that is set as a dangerous vehicle by another vehicle even if it cannot communicate with the own vehicle. A record about is registered. The control unit 10 executes the process of S1150 based on the record registered in the surrounding vehicle list having such characteristics. This point is different from the wireless communication device 1 of the first embodiment.

  If the control unit 10 determines that the value δV obtained in S1120 is greater than any of the values δVr indicated by the records registered in the surrounding vehicle list (Yes in S1150), the control unit 10 proceeds to S1160 and transmits the packet transmission source. The vehicle is determined to be “high risk” with respect to the host vehicle, and the transmission source dangerous vehicle is determined to be “low risk” with respect to the host vehicle (S1165). Thereafter, the process proceeds to S1180.

  On the other hand, when it is determined that the value δV obtained in S1120 is the same as or smaller than any of the values δVr indicated by the records registered in the surrounding vehicle list (No in S1150), the control unit 10 It is determined that the vehicle is “low risk” with respect to the host vehicle (S1170), and thereafter, the process proceeds to S1175.

Moreover, if transfering to S1175, the control part 10 will perform the transmission source dangerous vehicle determination process shown in FIG. 21, in order to evaluate the danger level with respect to the own vehicle of a transmission source dangerous vehicle.
In addition, FIG. 21 is a flowchart showing the transmission source dangerous vehicle determination process which the control part 10 performs by S1175. FIG. 22 is a flowchart showing the identity determination process executed by the control unit 10 in S1210 of the transmission source dangerous vehicle determination process.

  When starting the transmission source dangerous vehicle determination process in S1175, the control unit first sets the position coordinate Xd of the transmission source dangerous vehicle indicated by the communication packet received this time as the position coordinate Xc of the comparison target vehicle in S1210. (Xc = Xd), the identity determination process shown in FIG. 22 is executed.

  When the identity determination process is started, the control unit 10 first searches the surrounding vehicle list for a record of a dangerous vehicle currently set for the own vehicle (a record with a dangerous vehicle flag having a value of 1). Based on the position coordinates Xr, speed vector Vr, and time stamp Tr of the dangerous vehicle shown, the current position coordinates Xn of the dangerous vehicle are estimated by the same method as the process of S345 in the first embodiment (S1310).

  When the position coordinate Xn is estimated, the control unit 10 calculates an error εc = | Xc−Xn | between the preset position coordinate Xc of the comparison target vehicle and the estimated current position coordinate Xn of the dangerous vehicle. It is calculated (S1320), and it is determined whether or not the error εc is not more than a preset threshold value (S1330).

  If it is determined that the error εc is equal to or less than the threshold value (Yes in S1330), it is determined that the comparison target vehicle is the same vehicle as the currently set dangerous vehicle (S1340), and the identity determination process ends. On the other hand, if it is determined that the error εc is greater than the threshold value (No in S1330), it is determined that the comparison target vehicle is not the same vehicle as the currently set dangerous vehicle (S1350), and the identity determination process ends.

In S1210, the identity determination process with such contents is executed by setting the position coordinate Xd of the transmission source dangerous vehicle indicated by the communication packet received this time as the position coordinate Xc of the comparison target vehicle.
Then, when the processing in S1210 is completed, the control unit 10 determines whether or not the comparison target vehicle is determined to be the same vehicle as the currently set dangerous vehicle in the identity determination processing (S1220) and compared. If it is determined that the target vehicle is determined to be the same vehicle as the dangerous vehicle (Yes in S1220), the process proceeds to S1260, where it is determined that the transmission source dangerous vehicle is “low risk” with respect to the own vehicle. Thereafter, the transmission source vehicle determination process is terminated.

  On the other hand, if the control unit 10 determines that the comparison target vehicle is not determined to be the same vehicle as the dangerous vehicle (No in S1220), the control unit 10 proceeds to S1230, and the transmission source dangerous vehicle is currently set as the own vehicle. It is determined whether the vehicle is more dangerous than the dangerous vehicle.

  Specifically, the absolute value | Vd−Vs | of the relative speed vector of the transmission source dangerous vehicle based on the own vehicle is calculated based on the speed vector Vd of the transmission source dangerous vehicle and the speed vector Vs of the own vehicle. Whether or not the calculated absolute value | Vd−Vs | of the relative speed vector of the transmission source dangerous vehicle is larger than a value δVr (relative speed vector absolute value) indicated by the record of the dangerous vehicle currently set in the own vehicle. By determining, it is determined whether or not the transmission source dangerous vehicle is more dangerous than the dangerous vehicle currently set for the host vehicle.

  If the value | Vd−Vs | is larger than the value Vr of the dangerous vehicle, it is determined here that the transmission-source dangerous vehicle is more dangerous than the dangerous vehicle currently set as the own vehicle (Yes in S1230). . On the other hand, when the value | Vd−Vs | is equal to or less than the dangerous vehicle value Vr, it is determined that the transmission-source dangerous vehicle is not more dangerous than the dangerous vehicle currently set as the own vehicle (No in S1230).

  Then, if it is determined that the transmission source dangerous vehicle is not more dangerous than the dangerous vehicle currently set for the own vehicle (No in S1230), the process proceeds to S1260, and the transmission source dangerous vehicle determines that “the risk level is low”. Is determined. Thereafter, the transmission source dangerous vehicle determination process is terminated.

  On the other hand, if it is determined that the transmission source dangerous vehicle is more dangerous than the dangerous vehicle currently set as the own vehicle (Yes in S1230), the control unit 10 proceeds to S1240 and the own vehicle is more than the packet transmission source vehicle. Also, it is determined whether or not the vehicle is close to the transmission source dangerous vehicle. That is, the relative distance | Xd−Xs | between the host vehicle and the transmission source dangerous vehicle is calculated and received based on the position coordinate Xs of the host vehicle and the position coordinate Xd of the transmission source dangerous vehicle indicated by the received communication packet. The relative distance | Xd−X | between the packet transmission source vehicle and the transmission source dangerous vehicle is calculated based on the position coordinate Xd of the transmission source dangerous vehicle indicated by the transmitted communication packet and the position coordinate X of the packet transmission source vehicle. It is determined whether or not Xd−Xs | is also smaller than relative distance | Xd−X | (whether or not | Xd−Xs | <| Xd−X |).

  If it is determined that the host vehicle is not closer to the transmission source dangerous vehicle than the packet transmission source vehicle (No in S1240), the control unit 10 proceeds to S1260, and the transmission source dangerous vehicle is “ It is determined that the risk level is “low”. Thereafter, the transmission source dangerous vehicle determination process is terminated.

  On the other hand, if it is determined that the host vehicle is closer to the transmission source dangerous vehicle than the packet transmission source vehicle (Yes in S1240), the control unit 10 proceeds to S1250, and the transmission source dangerous vehicle is in response to the host vehicle. It is determined that the risk level is high. Thereafter, the transmission source dangerous vehicle determination process is terminated.

  In addition, when the transmission source dangerous vehicle determination process is completed in S1175 as described above, the control unit 10 proceeds to S1180 and executes the first update setting process illustrated in FIG. FIG. 23 is a flowchart showing the first update setting process executed by the control unit 10.

  When the first update setting process is started, the control unit 10 selects one of the records registered in the surrounding vehicle list as a process target record (S1410), and the position coordinates Xr of the dangerous vehicle indicated by the process target record. Based on the speed vector Vr and the time stamp Tr, the current position coordinates Xn of the vehicle corresponding to this record are estimated by the above-described method (S1420).

  When this process is finished, the control unit 10 calculates an error ε = | X−Xn | between the position coordinate X of the packet transmission source vehicle indicated by the communication packet received this time and the estimated current position coordinate Xn. (S1430). Thereafter, it is determined whether or not the error ε has been calculated for all records registered in the surrounding vehicle list (S1440). If the error ε has not been calculated for all records (No in S1440), the process proceeds to S1410. Then, one unprocessed record is selected as a process target record from the surrounding vehicle list, and the processes after S1420 are executed.

  In this way, the control unit 10 switches the processing target records, repeatedly executes the processing of S1410 to S1440, and calculates the error ε for each record registered in the surrounding vehicle list. If it is determined that the error ε has been calculated for all records (Yes in S1440), the process proceeds to S1450, and the error ε that takes the minimum value in the group of calculated errors ε is equal to or less than a preset threshold value. It is determined whether or not.

  If it is determined that the minimum value of the error ε is equal to or less than the threshold value (Yes in S1450), the process proceeds to S1470, where the record having the minimum error ε is determined to be a record of the same vehicle as the current packet transmission source vehicle. The record with the smallest error ε is set as the update target record. Thereafter, the process proceeds to S1475.

  In S1475, the control unit 10 determines the position coordinate X and the velocity vector V of the packet transmission source vehicle described in the communication packet received this time, the relative distance D and the relative speed of the packet transmission source vehicle obtained in S1120. Based on the vector absolute value δV, the contents of the update target record are updated by the same method as in S375 in the first embodiment. However, in this embodiment, the packet number is not written in the record. Thereafter, the process proceeds to S1480.

  On the other hand, if it is determined in S1450 that the minimum value of error ε is larger than the threshold (No in S1450), control unit 10 does not have a record of the same vehicle as the transmission source vehicle of the communication packet received this time in the surrounding vehicle list. Based on the position coordinate X and velocity vector V of the packet transmission source vehicle indicated by the received communication packet, and the relative distance D and relative velocity vector absolute value δV of the packet transmission source vehicle obtained in S1120, the first implementation A new record is generated by the same method as S365 in the example, and this is registered in the surrounding vehicle list (S1460). Thereafter, the process proceeds to S1480.

  After shifting to S1480, the control unit 10 determines whether or not the packet transmission source vehicle is determined to be “high risk” in the first half step (see S1160 and S1170) in the dangerous vehicle setting process. If it is determined that it is determined to be “large” (Yes in S1480), dangerous vehicle setting is performed on the record registered or updated this time (S1490). That is, the dangerous vehicle flag of the record registered in S1460 this time or the record updated in S1475 is set to the value 1, and the dangerous vehicle flags of all the records in the surrounding vehicle list excluding this record are reset to the value 0 (S1490).

  Moreover, if dangerous vehicle setting is performed, the control part 10 will transfer to S1495, will input dangerous vehicle update notification to a power cycle switching process task (refer FIG. 7), and will notify that the dangerous vehicle was updated. Thereafter, the first update setting process is terminated. On the other hand, when the control unit 10 determines that the packet transmission source vehicle is determined to be “low risk” in the first half of the dangerous vehicle setting process (No in S1480), the control unit 10 executes the processes of S1490 and S1495. The first update setting process ends without being updated (that is, without updating the dangerous vehicle).

  Further, when the first update setting process is ended in S1180, the control unit 10 proceeds to S1190 and executes the second update setting process illustrated in FIG. FIG. 24 is a flowchart illustrating a second update setting process executed by the control unit 10.

  When the second update setting process shown in FIG. 24 is started, the control unit 10 selects one of the records registered in the surrounding vehicle list as a process target record (S1510), and based on the process target record, A current position coordinate Xn of the vehicle corresponding to this record is estimated (S1520). Note that the processing of S1520 has the same contents as the processing of S1420 executed previously, and therefore may be processing of reading the position coordinates Xn of the processing target record estimated in S1420.

  When this process is finished, the control unit 10 calculates an error εd = | Xd−Xn | between the position coordinate Xd of the transmission source dangerous vehicle indicated by the communication packet received this time and the estimated current position coordinate Xn (S1530). ). Thereafter, it is determined whether or not the error εd has been calculated for all records registered in the surrounding vehicle list (S1540). If the error εd has not been calculated for all records (No in S1540), the process proceeds to S1510. Then, one unprocessed record is selected as a process target record from the surrounding vehicle list, and the processes after S1520 are executed.

  If it is determined that the error εd has been calculated for all records (Yes in S1540), the process proceeds to S1550, and the error εd that takes the minimum value in the group of calculated errors εd of each record is equal to or less than a preset threshold value. It is determined whether or not.

  If it is determined that the minimum value of the error εd is equal to or smaller than the threshold value (Yes in S1550), the process proceeds to S1570, and the record having the minimum error εd is determined to be a record of the same vehicle as the current transmission source dangerous vehicle. The record with the smallest error εd is set as the update target record. Thereafter, the process proceeds to S1575.

  In S1575, the control unit 10 determines the position coordinate Xd and speed vector Vd of the transmission source dangerous vehicle described in the communication packet received this time, the relative distance Dd and the relative speed of the transmission source dangerous vehicle obtained in S1125. The content of the update target record is updated based on the vector absolute value δVd.

  Specifically, the position coordinate Xr indicated by the update target record is updated to the position coordinate Xd of the transmission source dangerous vehicle indicated by the communication packet received this time, and the speed vector Vr indicated by the update target record is updated by the communication packet received this time. The speed vector V of the transmission source dangerous vehicle shown is updated.

  Similarly, the relative distance Dr indicated by the update target record is updated to the relative distance Dd calculated at S1125 based on the communication packet received this time, and the relative speed evaluation value δVr indicated by the update target record is updated at the relative speed calculated at S1125. The vector absolute value δVd is updated. Also, the time stamp Tr is updated to the current time. However, here, the dangerous vehicle flag of the update target record is not updated.

If the contents of the update target record are updated in this way, the process proceeds to S1580.
On the other hand, if it is determined in S1550 that the minimum value of the error εd is larger than the threshold (No in S1550), the control unit 10 includes a record of the same vehicle as the transmission source dangerous vehicle indicated by the communication packet received this time in the surrounding vehicle list. Based on the position coordinates Xd and speed vector Vd of the transmission source dangerous vehicle indicated by the received communication packet, and the relative distance Dd and relative speed vector absolute value δVd of the transmission source dangerous vehicle obtained in S1125, a new record is determined. Is registered in the surrounding vehicle list (S1560).

  In the new record, each value Xr, Vr, Dr, δVr, Tr is described based on the contents of the received communication packet in the same manner as the processing in S1575. However, in S1575, the value 0 is described as the dangerous vehicle flag in the new record. In this way, when the processing in S1560 is completed, the control unit 10 proceeds to S1580.

  In S1580, the control unit 10 determines whether or not the transmission source dangerous vehicle is determined to be “high risk” in the first half step (see S1165 and S1175) in the dangerous vehicle setting process. If it is determined that it is determined that “the degree of risk is high” (Yes in S1580), dangerous vehicle setting is performed on the record registered or updated this time (S1590). That is, the dangerous vehicle flag of the record registered in S1560 this time or the record updated in S1575 is set to the value 1, and the dangerous vehicle flags of all the records in the surrounding vehicle list excluding this record are reset to the value 0 (S1590).

  When the dangerous vehicle setting is performed, the control unit 10 proceeds to S1595, inputs a dangerous vehicle update notification to the power cycle switching processing task (see FIG. 7), and notifies that the dangerous vehicle has been updated. Thereafter, the second update setting process is terminated. On the other hand, when the control unit 10 determines that the transmission source dangerous vehicle is determined to be “low risk” (No in S1580), the control unit 10 updates the dangerous vehicle without executing the processing of S1590 and S1595. The second update setting process ends. Further, when the second update setting process is ended in S1190, the control unit 10 once ends the dangerous vehicle setting process.

  The wireless communication device 1 according to the present embodiment has been described above. However, in this wireless communication device 1, the relative speed vector absolute value of the dangerous vehicle set in the other vehicle is relative to the dangerous vehicle set in the own vehicle. If the risk vector is greater than the absolute value of the speed vector and the danger level of the dangerous vehicle set in the other vehicle is higher than the dangerous vehicle set in the own vehicle (Yes in S1240), it is set in the own vehicle. It is determined that the existing dangerous vehicle needs to be changed (Yes in S1580), and the dangerous vehicle set in the other vehicle is set as the dangerous vehicle of the own vehicle instead of the currently set dangerous vehicle.

  That is, according to the present embodiment, information on a vehicle that can receive a communication packet in another vehicle but cannot receive a communication packet in its own vehicle can be received as dangerous vehicle information. Based on the dangerous vehicle information, it is possible to know the presence of a dangerous vehicle that cannot communicate with the host vehicle. Therefore, according to the present embodiment, it is possible to appropriately set the dangerous vehicle and appropriately adjust the transmission power and the transmission cycle as compared with the first embodiment.

  Further, in this embodiment, only when the own vehicle is closer to the transmission source dangerous vehicle than the packet transmission source vehicle, the own vehicle's dangerous vehicle is switched to the transmission source dangerous vehicle. Also, when close to the transmission source dangerous vehicle, etc., by performing the above switching, communication between the transmission source dangerous vehicle and the packet transmission source vehicle interferes with communication between the transmission source dangerous vehicle and the host vehicle, It is possible to prevent the packet transmission source vehicle from performing communication necessary for collision avoidance.

  Next, the wireless communication device 1 according to the ninth embodiment will be described. However, in the wireless communication device 1 of the ninth embodiment, the transmission unit 21 has the same configuration as that of the eighth embodiment, and the communication packet to be transmitted has the configuration shown in FIG. The vehicle setting process is the same as that shown in FIG. 25, and the other configuration is basically the same as that of the wireless communication device 1 of the first embodiment. As an explanation, a configuration different from the wireless communication device 1 of the first embodiment will be described selectively.

  FIG. 25 is a flowchart showing a dangerous vehicle setting process repeatedly executed by the control unit 10 in the wireless communication device 1 according to the ninth embodiment. When the dangerous vehicle setting process is started, the control unit 10 executes the processes of S1610 to S1680 in the same manner as the processes of S210 to S280 of the first embodiment. When the update setting process is completed in S1680, the process proceeds to S1690, and the dangerous vehicle switching process shown in FIG. 26 is executed. Thereafter, the dangerous vehicle setting process is temporarily terminated.

  When the dangerous vehicle switching process is started in S1690, the control unit 10 determines whether or not the dangerous vehicle is updated in the immediately preceding process of S1680, and the transmission source vehicle of the communication packet received this time is set as the dangerous vehicle (S1710). If it is determined that the dangerous vehicle has been updated (Yes in S1710), the dangerous vehicle switching process is terminated without executing the processes of S1720 to S1750.

  On the other hand, when determining that the dangerous vehicle has not been updated (No in S1710), the control unit 10 proceeds to S1720, and uses the position coordinate Xd of the transmission source dangerous vehicle indicated by the communication packet received this time as the position of the comparison target vehicle. The coordinate determination process shown in FIG. 22 is executed by setting the coordinate Xc.

  When the process in S1720 ends, the control unit 10 determines whether or not the comparison target vehicle is determined to be the same vehicle as the currently set dangerous vehicle in the identity determination process (S1730), and the comparison is performed. If it is determined that the target vehicle is not determined to be the same vehicle as the dangerous vehicle (No in S1730), the dangerous vehicle switching process is terminated without executing the processes of S1740 to S1750.

  On the other hand, when it is determined that the comparison target vehicle is determined to be the same vehicle as the dangerous vehicle (Yes in S1730), the control unit 10 proceeds to S1740 and the own vehicle is more dangerous than the packet transmission source vehicle. It is determined whether or not the vehicle is far from the vehicle. That is, the relative distance | Xd−Xs | between the host vehicle and the transmission source dangerous vehicle is calculated and received based on the position coordinate Xs of the host vehicle and the position coordinate Xd of the transmission source dangerous vehicle indicated by the received communication packet. The relative distance | Xd−X | between the transmission source vehicle and the transmission source dangerous vehicle is calculated based on the position coordinate Xd of the transmission source dangerous vehicle and the position coordinate X of the transmission source vehicle indicated by the transmitted communication packet, and the relative distance | Xd− It is determined whether Xs | is also larger than the relative distance | Xd-X | (whether | Xd-Xs |> | Xd-X |).

  If it is determined that the host vehicle is not located farther from the transmission source dangerous vehicle than the packet transmission source vehicle (No in S1740), the control unit 10 ends the dangerous vehicle switching process without executing the process of S1750. If it is determined that the host vehicle is located farther from the transmission source dangerous vehicle than the packet transmission source vehicle (Yes in S1740), the process proceeds to S1750.

  Then, in S1750, the dangerous vehicle is set for the record with the larger relative speed evaluation value δVr next to the record currently set as the dangerous vehicle in the surrounding vehicle list, and the dangerous vehicle is set as the next vehicle. Update.

  That is, after the record currently set as a dangerous vehicle, the dangerous vehicle flag of the record having the larger relative speed evaluation value δVr is set to the value 1, and the dangerous vehicle flag of other records is set to the value 0, Set the vehicle as the next vehicle. Thus, the control unit 10 is a case where the dangerous vehicle set in the own vehicle and the transmission source dangerous vehicle are the same vehicle, and the own vehicle is farther from the transmission source dangerous vehicle than the packet transmission source vehicle. In step S1750, after switching the dangerous vehicle to the next vehicle, the dangerous vehicle switching process is terminated.

  The wireless communication device 1 according to the ninth embodiment has been described above. In the present embodiment, the same vehicle is set as a dangerous vehicle in the surrounding vehicle and the own vehicle, and the own vehicle is a neighboring vehicle. If the vehicle is at a position farther from the transmission source dangerous vehicle, the dangerous vehicle is switched to the next highest risk vehicle.

  Therefore, if vehicle-to-vehicle communication is performed using this wireless communication device 1, for example, when the following vehicle comes to the tail of the vehicle train in a traffic jam, the vehicles around the tail transmit all at once. By increasing the power for communication, it is possible to prevent communication interference from becoming severe and preventing the position information around the tail end from being transmitted to the following vehicle. Therefore, the wireless communication device 1 is very useful for collision avoidance.

  As mentioned above, although the Example of this invention was described, it cannot be overemphasized that this invention can take a various aspect, without being limited to the said Example.

2 is a block diagram illustrating a configuration of a wireless communication device 1. FIG. It is explanatory drawing (a) showing the structure of a communication packet, and the flowchart (b) showing the packet transmission process which the transmission part 21 performs. It is a flowchart showing the dangerous vehicle setting process which the control part 10 performs. It is explanatory drawing showing the structure of a surrounding vehicle list | wrist. It is a flowchart showing the update setting process which the control part 10 performs. It is a flowchart showing the process at the time of non-reception which the control part 10 performs. It is a flowchart showing the power cycle switching process which the control part 10 performs. It is the conceptual diagram (a) of a transmission power setting map, and the conceptual diagram (b) of a transmission period setting map. It is explanatory drawing regarding the determination method of a dangerous vehicle. It is a flowchart showing the dangerous vehicle setting process of 2nd Example. It is a flowchart showing the dangerous vehicle setting process of 3rd Example. It is explanatory drawing (b) regarding the flowchart (a) and area | region R showing the dangerous vehicle setting process of 4th Example. It is a flowchart showing the dangerous vehicle setting process of 5th Example. It is explanatory drawing regarding the definition of angle (theta). It is the flowchart (a) showing the dangerous vehicle setting process in 6th Example, and the conceptual diagram (b) of a transmission period setting map. It is explanatory drawing regarding speed component (delta) Ve. It is a flowchart showing the dangerous vehicle setting process of 7th Example. It is a conceptual diagram of the transmission period setting map in 7th Example. It is explanatory drawing showing the structure of the communication packet in an 8th Example. It is a flowchart showing the dangerous vehicle setting process of 8th Example. It is a flowchart showing the transmission source dangerous vehicle determination process which the control part 10 performs in an 8th Example. It is a flowchart showing the identity determination process which the control part 10 performs in an 8th Example. It is a flowchart showing the 1st update setting process which the control part 10 performs in an 8th Example. It is a flowchart showing the 2nd update setting process which the control part 10 performs in an 8th Example. It is a flowchart showing the dangerous vehicle setting process of 9th Example. It is a flowchart showing the dangerous vehicle switching process which the control part 10 performs in 9th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless communication apparatus, 10 ... Control part, 20 ... Communication part, 21 ... Transmission part, 25 ... Reception part, 50 ... Navigation apparatus, 51 ... Map database, 53 ... Display part, 55 ... Audio | voice output part, 57 ... State Detector

Claims (16)

A wireless communication device mounted on a vehicle,
Packet transmission that broadcasts a communication packet describing the motion state of the host vehicle as a radio signal around the host vehicle with a preset transmission power and transmission cycle based on the detection result of the detection means for detecting the motion state of the host vehicle Means,
A packet receiving means for receiving the communication packet broadcast from a wireless communication device mounted on each unspecified vehicle existing around the host vehicle;
Based on the content of the communication packet received by the packet receiving means, the degree of risk to the own vehicle of the transmission source vehicle that has transmitted the communication packet is evaluated, and the degree of risk to the own vehicle in the transmission source vehicle group is maximum. Vehicle setting means for setting the vehicle as a reference vehicle as a transmission condition setting reference,
Transmission condition setting means for setting at least one of the transmission power and the transmission cycle as the transmission condition based on the movement state of the reference vehicle with respect to the host vehicle set by the reference vehicle setting means,
With
The packet transmission means is configured to broadcast the communication packet at a transmission power and a transmission cycle that satisfy the transmission conditions set by the transmission condition setting means, and the reference vehicle set in the own vehicle Based on the contents of the communication packet received from the past, the communication packet describing the movement state of the reference vehicle set in the own vehicle together with the movement state of the own vehicle is broadcasted,
The wireless communication device further includes:
Each time the packet receiving unit receives the communication packet, the reference set in the own vehicle based on the movement state of the reference vehicle set in the transmission source vehicle of the communication packet indicated by the received communication packet Change necessity determination means for determining whether or not a vehicle needs to be changed
With
If the reference vehicle setting means determines that the change necessity determination means needs to be changed, the reference vehicle setting means replaces the currently set reference vehicle with the reference vehicle set as the transmission source vehicle. The wireless communication apparatus is set to the reference vehicle of the own vehicle . The reference vehicle setting means needs to change the reference vehicle when the risk of the reference vehicle set for the transmission source vehicle is higher than that for the reference vehicle set for the own vehicle. If it is determined that there is a risk level of the reference vehicle set as the transmission source vehicle with respect to the own vehicle is lower than the reference vehicle set as the own vehicle, there is no need to change the reference vehicle. The wireless communication device according to claim 1, wherein the wireless communication device is configured to make a determination.   A wireless communication device mounted on a vehicle,
  Packet transmission that broadcasts a communication packet describing the motion state of the host vehicle as a radio signal around the host vehicle with a preset transmission power and transmission cycle based on the detection result of the detection means for detecting the motion state of the host vehicle Means,
  A packet receiving means for receiving the communication packet broadcast from a wireless communication device mounted on each unspecified vehicle existing around the host vehicle;
  Based on the content of the communication packet received by the packet receiving means, the degree of risk to the own vehicle of the transmission source vehicle that has transmitted the communication packet is evaluated, and the degree of risk to the own vehicle in the transmission source vehicle group is maximum. Vehicle setting means for setting the vehicle as a reference vehicle as a transmission condition setting reference,
  Transmission condition setting means for setting at least one of the transmission power and the transmission cycle as the transmission condition based on the movement state of the reference vehicle with respect to the host vehicle set by the reference vehicle setting means,
  With
  The packet transmission means is configured to broadcast the communication packet at a transmission power and a transmission cycle that satisfy the transmission conditions set by the transmission condition setting means, and the reference vehicle set in the own vehicle Based on the content of the communication packet received in the past, the communication packet describing the movement state of the reference vehicle together with the movement state of the host vehicle is broadcast,
  The wireless communication device further includes:
  Whenever the packet receiving means receives the communication packet, based on the content of the received communication packet, the reference vehicle set as the transmission source vehicle of the communication packet and the reference vehicle set as the own vehicle And the same determination means for determining whether or not they are the same vehicle,
  When it is determined by the same determination means that the reference vehicle set as the transmission source vehicle and the reference vehicle set as the own vehicle are the same vehicle, the reference vehicle and the transmission A means for determining whether or not the reference vehicle set in the own vehicle needs to be changed based on a positional relationship between the original vehicle and the own vehicle, the distance from the reference vehicle to the transmission source vehicle Is a change necessity determination unit that determines that it is necessary to change the reference vehicle set in the own vehicle when the distance from the reference vehicle to the own vehicle is shorter than
  With
  If it is determined that the reference vehicle setting means needs to be changed by the change necessity determination means, the risk level for the own vehicle in the transmission source vehicle group is next to the currently set reference vehicle. Is set as the reference vehicle of the host vehicle instead of the currently set reference vehicle.
  A wireless communication apparatus. The detection means is configured to detect a speed vector of the host vehicle,
The wireless communication apparatus according to claim 1 , wherein the packet transmission unit describes at least a speed vector of the host vehicle as a motion state of the host vehicle in the communication packet to be broadcast. . The detection means is configured to be able to detect the position coordinates of the host vehicle,
The wireless communication apparatus according to claim 4 , wherein the packet transmission unit further describes a position coordinate of the host vehicle as a motion state of the host vehicle in the communication packet to be broadcast. The reference vehicle setting means sets the vehicle having the maximum risk as the reference vehicle in the vehicle group existing within a predetermined distance with respect to the own vehicle in the transmission source vehicle group. The wireless communication apparatus according to claim 5, wherein: The reference vehicle setting means includes a relative speed vector of a transmission source vehicle with respect to the own vehicle in the transmission source vehicle group, a vector having an existence point of the transmission source vehicle as a start point and an existence point of the own vehicle as an end point. The wireless communication device according to claim 5 , wherein a vehicle having the highest degree of risk is set as the reference vehicle in a vehicle group having an angle of less than or equal to a threshold value. For each communication packet received by the packet receiving means, the transmission source vehicle travels based on the position coordinates of the own vehicle detected by the detection means and the position coordinates of the transmission source vehicle described in the communication packet. Road relation judging means for judging whether or not the road satisfies a predetermined relation with the road on which the host vehicle is traveling,
In accordance with the determination result of the road relationship determination unit, the reference vehicle setting unit is configured to select the risk among the vehicle group that travels on a road that satisfies a predetermined relationship with a road on which the host vehicle travels. The wireless communication device according to any one of claims 5 to 7 , wherein a vehicle having a maximum degree is set as the reference vehicle. The reference vehicle setting means has the highest degree of risk in a group of vehicles in which no other vehicle exists between the location of the transmission source vehicle and the location of the own vehicle in the transmission source vehicle group. The wireless communication device according to claim 5 , wherein a vehicle is set as the reference vehicle. The transmission condition setting means sets the transmission power based on the relative distance of the reference vehicle with respect to the host vehicle as the movement state of the reference vehicle. The longer the relative distance, the larger the transmission power. The wireless communication apparatus according to any one of claims 5 to 9 , wherein the wireless communication apparatus is set as follows . The reference vehicle setting means, wherein the risk is greatest vehicle, according to claim 4 in which the magnitude of the relative velocity vector of the vehicle as a reference is the greatest source vehicle, and sets the reference vehicle The wireless communication apparatus according to claim 10 . The reference vehicle setting means, as the vehicle with the highest degree of risk, a relative speed vector of a transmission source vehicle based on the own vehicle, a unit vector extending from the location of the transmission source vehicle to the location of the own vehicle, The wireless communication device according to any one of claims 5 to 10 , wherein a transmission source vehicle having the largest inner product is set as the reference vehicle. The reference vehicle setting means determines whether or not there is a possibility that the transmission source vehicle collides with the own vehicle with respect to the transmission source vehicle that has transmitted the communication packet. Predicting the remaining time until the collision, and selecting the vehicle having the minimum remaining time until the collision from the group of transmission source vehicles determined to be likely to collide as the vehicle having the maximum risk. It sets to a vehicle. The radio | wireless communication apparatus in any one of Claims 5-10 characterized by the above-mentioned. The transmission condition setting means sets the transmission cycle based on the remaining time until the reference vehicle collides with the host vehicle as the movement state of the reference vehicle. , to set the transmission cycle shorter value
The wireless communications apparatus of claim 13, wherein the this. The transmission condition setting means sets the transmission cycle based on the relative speed vector of the reference vehicle relative to the host vehicle as the motion state of the reference vehicle , and the relative speed vector is large. The wireless communication apparatus according to claim 4 , wherein the transmission cycle is set to a shorter value . The transmission condition setting means includes, as a movement state of the reference vehicle, a relative speed vector of the reference vehicle with respect to the own vehicle, and a unit vector extending from an existing point of the reference vehicle toward the existing point of the own vehicle. The transmission cycle is set based on a speed component in the vehicle direction of the reference vehicle represented by an inner product, and the transmission cycle is set to a shorter value as the speed component is larger. The wireless communication apparatus according to any one of claims 5 to 13 .