JP2007088583A - Inter-vehicle communication system and radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inter-vehicle communication system and a radio communication apparatus in which radio communication interference is avoided. <P>SOLUTION: In the inter-vehicle communication system 1 having a plurality of vehicles 2 each mounting a radio communication apparatus 11 and transmitting/receiving transmission data between respective radio communication apparatus 11, a wireless channel CH is assigned to every lane R and the radio communication apparatus 11 of each vehicle 2 performs wireless communication by using the wireless channel CH assigned to the lane R on which the vehicle 2 is traveling. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to wireless communication between vehicles, and more particularly to a wireless communication technique suitable for use in a road traffic system.

  In recent years, with the development of IT technology, road traffic systems and information communication systems are linked so that vehicles such as automobiles traveling on the road reflect information from other vehicles and the ground in their own driving. On the other hand, it has been proposed to construct an intelligent transport system (ITS) which is an advancement of the road traffic system. In this intelligent road transportation system, each vehicle is automatically platted on an automobile-only road such as an expressway to enable automatic driving of the vehicle and reduce driver fatigue. Attempts have been made to improve transportation efficiency by keeping the distance between vehicles as short as possible (see, for example, Patent Document 1).

By the way, in order to realize the automatic platooning, it is necessary to perform inter-vehicle wireless communication that is excellent in real time and highly reliable. As a wireless communication control method used for such inter-vehicle wireless communication, a centralized control method using a base station (polling / selecting method), and direct communication between vehicles without using a base station (so-called Point -to-Point connection).
In the centralized control method, since the base station controls the wireless communication between the vehicles, it is possible to realize highly reliable communication without causing a wireless communication collision. However, since a vehicle moves at a high speed on an automobile exclusive road or the like, a wide service area is required, the system becomes complicated, and the cost increases.
On the other hand, since the contention method does not require a base station, a vehicle-to-vehicle communication system can be constructed at a relatively low cost. For this reason, in recent years, the use of the contention method as a wireless communication control method for automatic platooning has been studied.
JP 2001-283372 A

However, in the contention system, there is a problem that, when a plurality of platoons run in parallel or another platoon runs in the vicinity, radio communication interference occurs between the platoons.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an inter-vehicle communication system and a wireless communication device that can avoid wireless communication interference.

  In order to achieve the above object, the present invention provides a vehicle having a plurality of vehicles equipped with wireless communication devices, and a wireless channel for each lane in an inter-vehicle communication system that transmits and receives transmission data between the wireless communication devices. Each of the wireless communication devices of each of the vehicles performs wireless communication using a wireless channel assigned to the traveling lane.

  Further, in the present invention, in the above invention, when the vehicle changes lanes, the wireless communication device mounted on the vehicle has a lane before the change and a lane after the change until the lane change is completed. Wireless communication is performed using a wireless channel assigned to the network.

  According to the present invention, in the above invention, each of the vehicles includes a position detection unit that detects a current position of the host vehicle, and a radio channel assigned to the lane based on the current position detected by the position detection unit. A wireless channel specifying unit for specifying, wherein each of the wireless communication devices performs wireless communication using the wireless channel specified by the wireless channel specifying unit.

  Moreover, the present invention is characterized in that, in the above invention, a roadside communication device for transmitting a radio channel assigned to the lane to a vehicle traveling in the lane is disposed on the road.

  Further, the present invention is the above invention, wherein each of the vehicles has position detecting means for detecting a current position of the own vehicle, and each of the wireless communication devices includes the current position of the own vehicle in the transmission data. And when the transmission data is received from the wireless communication device of the other vehicle, at the timing when the time corresponding to the relative distance between the other vehicle and the host vehicle has elapsed from the timing of the reception, The position is included in the transmission data for transmission.

  Further, the present invention is the above invention, wherein each of the wireless communication devices has a relative distance between the other vehicle and the host vehicle from a timing at which transmission data including the current position of the other vehicle is received from another wireless communication device. When new transmission data is received before the corresponding time elapses, the relative distance between the vehicle that transmitted the new transmission data and the host vehicle is determined from the timing at which the new transmission data is received. The transmission data is transmitted when a corresponding time has elapsed.

  In addition, according to the present invention, in the above invention, when each of the wireless communication devices receives transmission data including the current position of the other vehicle from another wireless communication device, the other vehicle is located behind the own vehicle in the traveling direction. If it is located, transmission of the transmission data is prohibited.

  Moreover, the present invention is characterized in that, in the above invention, each of the vehicles travels in a platoon based on the transmission data transmitted from each of the wireless communication devices.

  In order to achieve the above object, the present invention provides a wireless communication device that is mounted on a vehicle and transmits / receives transmission data to / from a wireless communication device mounted on another vehicle. The wireless channel is acquired, and wireless communication is performed using the wireless channel.

  According to the present invention, the wireless channel is assigned to each lane, and each wireless communication device of each vehicle is configured to perform wireless communication using the wireless channel assigned to the lane in which the vehicle is traveling. Wireless communication interference with a traveling vehicle can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a configuration of an inter-vehicle communication system 1 according to the present embodiment. This inter-vehicle communication system 1 is a communication system for realizing platooning by automatic driving control of a vehicle, and as shown in the figure, a plurality of vehicles 2-1, 2-2. If there is no need to distinguish between the two, each vehicle 2 is equipped with a wireless communication device 11, a vehicle control device 12, and a car navigation device 13 as position detecting means. In the inter-vehicle communication system 1, each vehicle 2 travels in a row while maintaining a substantially constant inter-vehicle distance L (for example, 10 M (meters)).

  Each of the wireless communication devices 11 has a predetermined radius of the wireless communication area A2-1, A2-2, ... (hereinafter referred to as a wireless communication area A when there is no need to distinguish each wireless communication area). ) And directly wirelessly communicate with other wireless communication devices 11 existing in the wireless communication area A without using a base station or the like. Identification information such as an ID and an address is assigned to each wireless communication device 11 in advance, and this identification information is used as information indicating a destination or a transmission source terminal during communication. For example, in the reception data processing during the wireless reception operation, when the wireless communication device 11 receives data, when the identification information indicating the destination of the data matches the identification information of the own device, the received data is automatically processed. Process as data addressed to the device. At this time, the wireless communication device 11 that has received the data can determine the wireless communication device 11 of the transmission source by referring to the identification information indicating the transmission source of the data.

  Here, in order to realize the automatic driving control, traveling information including at least the current position, the moving direction, and the moving speed of each vehicle 2 is necessary to keep the distance between the vehicles 2 properly. In particular, in the present embodiment, since the travel information of each vehicle 2 is not centrally managed by a base station (control station) or the like, each vehicle 2 is present around the own vehicle along with the travel information of the own vehicle. It is necessary to grasp vehicle travel information and perform automatic operation control based on the travel information. Therefore, the wireless communication device 11 is configured to transmit the current position of the host vehicle, the traveling direction, and the vehicle speed together with the identification information to the other wireless communication devices 11. Specifically, the vehicle control device 12 acquires the current position, moving direction, and moving speed of the host vehicle from the car navigation device 13, and this travel information is mounted on the other vehicle 2 from the wireless communication device 11 of the host vehicle. It is configured to be transmitted to the wireless communication device 11.

FIG. 2 is a block diagram illustrating a functional configuration of the wireless communication device 11.
As shown in this figure, the wireless communication device 11 includes a CPU 101, a memory 102, a data link unit 103, a modem unit 104, an RF unit 105, and an antenna 106.
The CPU 101 controls each unit of the wireless communication device 11. The CPU 101 is connected to the vehicle control device 12 through an interface (not shown), and the vehicle control device 12 acquires travel information from the car navigation device 13 and inputs the travel information to the CPU 101.
The memory 102 stores various programs, data, variables, and the like executed by the CPU 101, and also functions as a communication buffer that temporarily stores traveling information of the host vehicle 2 at the time of wireless communication operation.

The data link unit 103 processes transmission / reception data based on a predetermined wireless communication protocol. Specifically, when the data link unit 103 receives data to be transmitted from the CPU 101, the data link unit 103 generates transmission data compliant with the wireless communication protocol and outputs the transmission data to the modulation / demodulation unit 104. Is received, the received data is processed in accordance with the wireless communication protocol and output to the CPU 101.
The modulation / demodulation unit 104 modulates / demodulates transmission / reception data based on, for example, a frequency division division communication system, and modulates transmission data received from the data link unit 103 during data transmission and outputs the data to the RF unit 105. The received data received from the RF unit 105 is demodulated and output to the data link unit 103.

An RF (Radio Frequency) unit 105 processes a radio signal transmitted / received via an antenna based on the predetermined radio communication method, and at the time of data transmission, transmits transmission data received from the modem unit 104 to radio communication. A radio signal is generated by being superimposed on a carrier wave in the frequency band of the radio channel to be used and output to the antenna 106. Thereby, the radio wave including the transmission data is transmitted from the antenna 106 to the outside. At the time of data reception, the RF unit 105 receives a radio signal received by the antenna 106, separates a carrier wave, generates reception data, and outputs the received data to the modem unit 104. As described above, the received data is processed by the modem unit 104 and the data link unit 103, and for example, traveling information of the other vehicle 2 is output to the CPU 101.
In the present embodiment, the vehicle control device 12 determines the wireless channel used for communication by the wireless communication device 11 according to the lane in which the vehicle 2 travels, which will be described later.

Here, in the present embodiment, among the current position, moving direction, and moving speed of the vehicle 2 included in the travel information, the current position of each vehicle 2 is used as the transmission timing, so that each vehicle 2 in the platoon is The wireless signal collision is prevented.
In other words, in the present embodiment, each vehicle 2 is fixed between the vehicles 2 that perform the convoy travel, for example, each vehicle 2 performs wireless transmission in order from the leading vehicle 2 to the following vehicle 2. Wireless transmission is performed in order, and each vehicle 2 transmits wirelessly in order in this way, thereby avoiding the occurrence of wireless signal collision. In the following description, as a case where each vehicle 2 wirelessly transmits in a certain order, one vehicle is wirelessly transmitted in order from the leading vehicle 2 in the traveling direction to the following vehicle 2 among the plurality of vehicles 2 traveling in the platoon. Explain the case.

FIG. 3 is a diagram showing the transmission timing during the wireless transmission operation. As shown in this figure, in a wireless transmission period T from when a certain vehicle 2 performs wireless transmission until the next vehicle 2 (wireless communication device 11) performs wireless transmission, a wireless communication period TA and a wireless communication pause A period TB and a radio channel monitoring period TC are provided, and a radio transmission frame (transmission data) 300 is transmitted from the vehicle 2 (radio communication apparatus 11) that performs radio transmission in the radio communication period TA among these periods. .
The wireless transmission frame 300 stores traveling information including the current position of the vehicle 2. By transmitting the wireless transmission frame 300, traveling information of the host vehicle 2 is notified to other nearby vehicles 2. It has become so.

The configuration of the wireless transmission frame 300 will be described in detail. The wireless transmission frame 300 is roughly divided into a wireless header section 301 and a wireless data section 302, and the wireless header section 301 includes a wireless header 300A. The data unit 302 includes a transmission source ID 300B, a transmission vehicle position 300C, and a wireless tailor 300X.
The wireless header section 301 stores header information that conforms to the wireless communication method used in the inter-vehicle communication system 1, and this header information is stored in the wireless header 300A.

The wireless data unit 302 stores various data such as identification information of the transmission source vehicle 2 and travel information including the current position. The identification information of the transmission source wireless communication device 11 (vehicle 2) is stored in the transmission source. It is stored in the ID 300B, and the current position information is stored in the transmitting vehicle position 300C. As the current position information, for example, coordinate values expressed by latitude and longitude are used.
The wireless tailor 300X is a frame check sequence (FCS) for the wireless communication device 11 that has received the wireless transmission frame 300 to detect an error (error) in the received wireless transmission frame 300. Data for CRC (Cyclic Redundancy Check) is stored. Further, the wireless header portion 301 and the wireless data portion 302 are identified based on the data stored in the wireless tailor 300X.
Note that a configuration may be adopted in which dedicated information for identifying the wireless header portion 301 and the wireless data portion 302 is added to the wireless transmission frame 300.
In addition to the above information, travel information such as vehicle speed and moving direction is stored in the wireless data unit 302, and these travel information is transmitted to the surrounding other vehicle 2.

The wireless communication suspension period TB is a period for the other vehicle 2 (wireless communication apparatus 11) to receive and process the wireless transmission frame 300 transmitted in the wireless communication period TA. A fixed value is used for the time length of the wireless communication suspension period TB in the entire inter-vehicle communication system 1, and it is necessary for the receiving operation including the processing capability of each wireless communication device 11 (various processing such as decoding processing of received data). A time length considering time is set.
The radio channel monitoring period TC is a period provided to avoid a collision of the radio transmission frames 300 transmitted by each vehicle 2 (radio communication apparatus 11). In the radio channel monitoring period TC, radio communication is performed. For example, the device 11 performs carrier sense to determine whether or not the wireless channel is in use, and if it is in use, the wireless transmission operation is prohibited (stopped).

Here, the time length of the wireless channel monitoring period TC is not a fixed time length in each vehicle 2, but the relative distance between the vehicle 2 that transmitted the wireless transmission frame 300 in the wireless transmission period T and each vehicle 2 It is designed to be longer depending on the situation. Accordingly, the start timing t3 of the next wireless communication period TA comes from the vehicle 2 with the shortest relative distance between the vehicles, and the transmission operation of the wireless transmission frame 300 is performed. Transmission operation is prohibited.
In this embodiment, the data link unit 103 of the wireless communication apparatus 11 performs such determination of the time length of the wireless channel monitoring period TC and determination of the wireless transmission timing Ts (start timing of the wireless communication period TA). It is said.

FIG. 4 is a block diagram showing a functional configuration for determining the radio channel monitoring period TC and the radio transmission timing Ts among the functional configurations of the data link unit 103.
As shown in this figure, the data link unit 103 includes a position information processing unit 401, a counter arrival value calculation unit 402, a wireless data unit detection unit 403, a counter unit 404, an FCS determination unit 405, and a comparison determination unit. 406.
The position information processing unit 401 receives the received wireless transmission frame 300 and the position information of the own vehicle 2, and receives the position information of the transmission source vehicle 2 stored in the transmission vehicle position 300 </ b> C of the wireless transmission frame 300, The relative distance between the vehicles is calculated from the position information of the vehicle 2 and is output to the counter arrival value calculation unit 402. At this time, the position information processing unit 401 adds a positive sign to the relative distance when the transmission source vehicle 2 is located in front of the host vehicle 2, and adds a negative sign to the relative distance when located at the rear. Thus, it is possible to determine whether the transmission source vehicle 2 is located before or after the host vehicle 2.

  The counter arrival calculation unit 402 determines a radio channel monitoring period TC having a time length proportional to the relative information between the vehicles calculated by the position information processing unit 401, and the radio channel monitoring period TC and a predetermined time length. The wireless transmission timing Ts is calculated based on the wireless communication suspension period TB and the end timing t1 (see FIG. 3) of the wireless communication period TA, and is output to the comparison determination unit 406.

  The wireless data part detection unit 403 detects the start and end of the wireless data part 302 of the received wireless transmission frame 300. In addition, when the start of the wireless data unit 302 is detected, the wireless data unit detection unit 403 outputs a count stop signal to the counter unit 404, and when the end of the wireless data unit 302 is detected, A count start signal is output to the counter unit 404.

The counter unit 404 is a counter for counting the respective timings of the wireless communication suspension period TB and the wireless channel monitoring period TC based on a clock signal of a clock circuit (not shown) built in the wireless communication apparatus 11.
More specifically, when the count start signal is input from the wireless data unit detection unit 403, the counter unit 404 clears the counter value, counts up the counter from the initial value, and starts counting. . Thereby, the count starts from the end timing of the wireless data unit 302, that is, the end timing t1 of the wireless communication period TA.
The counter unit 404 counts up the counter when a count stop signal is input from the wireless data unit detection unit 403 or when a wireless transmission start signal is input from the comparison determination unit 406 described later. Stop. Therefore, the counter unit 404 starts the counting operation from the end timing t1 of the wireless communication period TA and next receives the wireless transmission frame 300 transmitted by another wireless communication device 11, or the own device transmits the wireless transmission frame. When the transmission of 300 is started, the counting operation is stopped.

The FCS determination unit 405 performs error determination on the received wireless transmission frame 300 and outputs a determination result to the comparison determination unit 406.
The comparison determination unit 406 detects the arrival of the radio transmission timing Ts by comparing the time until the radio transmission timing Ts output from the counter arrival calculation unit 402 and the counter value of the counter unit 404, for example, the CPU 101 or the like. A radio transmission start signal is output to each unit that controls radio transmission.
At this time, if the determination result of the FCS determination unit 405 determines that the received wireless transmission frame 300 has an error, the comparison determination unit 406 stops the detection processing of the wireless transmission timing Ts. This prevents the start of wireless transmission based on the wireless transmission frame 300 including an error.

Here, the counter arrival calculation unit 402 outputs a comparison determination stop value when a negative sign is given to the relative distance between the vehicles received from the position information processing unit 401. Thereby, based on reception of the wireless transmission frame 300 transmitted from the vehicle 2 behind the host vehicle 2, the wireless communication device 11 of the host vehicle 2 is prevented from starting wireless transmission.
Further, as described above, since the radio channel monitoring period TC becomes longer in proportion to the relative distance between the vehicles, the radio of the vehicle 2 that has transmitted the radio transmission frame 300 first and the vehicle 2 immediately after the shortest relative distance. The communication device 11 precedes the other vehicle 2 and the start timing t3 of the next wireless communication period TA arrives, and the wireless transmission operation is started. At this time, in the wireless communication device 11 of the other vehicle 2, the new wireless transmission frame 300 is received and the counting operation of the counter unit 404 is stopped, so that the wireless transmission of the own device is stopped. Hereinafter, the operation at this time will be described in more detail with reference to FIG.

  FIG. 5 is a diagram illustrating the operation timing of the wireless communication device 11 mounted on each of the four vehicles 2-1 to 2-4 (see FIG. 1) traveling in a row. In this figure, the wireless transmission frame 300 transmitted from the second vehicle 2-2 from the top of the four vehicles 2-1 to 2-4 traveling in a row is shown as the vehicle 2-2. The case where the other vehicles 2-3 and 2-4 existing in the wireless communication area A2-2 of FIG. Moreover, in order to distinguish the radio | wireless transmission frame 300 which each vehicle 2-2 to 2-4 transmits, it shall attach | subject the code | symbol 300B-300D to each.

As described above, the wireless transmission frames 300 </ b> B to 300 </ b> D store travel information such as the moving speed and the traveling direction along with the position information of the transmission source vehicle 2. Based on the travel information, each vehicle 2 performs automatic driving control for platooning, and each wireless communication device 11 performs a wireless transmission operation according to the above procedure.
That is, when the wireless communication frames 300B from the second vehicle 2-2 from the top are received by the wireless communication devices 11 of the other vehicles 2-3 and 2-4, each wireless communication device 11 receives the next wireless transmission timing Ts. Start counting. At this time, in the wireless communication device 11 of the leading vehicle 2-1 located in front of the second vehicle 2-2, since the relative distance to the second vehicle 2-2 is a negative sign, The wireless transmission is stopped without counting the transmission timing Ts.

  Further, since each vehicle 2-2 to 2-4 travels in a row with a constant inter-vehicle distance L, the wireless channel monitoring period TC set by the wireless communication device 11 of the third vehicle 2-3 from the head is set. The time length is about half of the time length of the radio channel monitoring period TC set by the radio communication device 11 of the last vehicle 2-4. In this way, the time length of the radio channel monitoring period TC differs between the third vehicle 2-3 and the last vehicle 2-4, and the third vehicle 2 than the last vehicle 2-4. -3 wireless communication device 11 first reaches the wireless transmission timing Ts, and starts transmitting the wireless transmission frame 300C.

At this time, since the last vehicle 2-4 is within the wireless channel monitoring period TC, the wireless transmission timing Ts is recalculated again with the wireless transmission of the third vehicle 2-3. If wireless transmission is not performed from another wireless communication device 11 by the recalculated wireless transmission timing Ts, transmission of the wireless transmission frame 300D is started at the wireless transmission timing Ts.
Thus, if the above procedure is used, wireless communication can be realized without causing a wireless signal collision during wireless transmission.

Next, the wireless communication operation of the leading vehicle 2-1 of the group of vehicles traveling in the row, that is, the vehicle 2 in which no other vehicle 2 exists in the forward direction will be described.
In general, each vehicle 2 that travels in a row requires wireless transmission of travel information of the host vehicle 2 at regular time intervals in order to avoid accidents such as a collision of the vehicle 2. When determining this fixed time interval, the distance between vehicles and the traveling speed (moving speed) during traveling are important parameters.

According to Ichiro Emori's “New Edition Car Accident Engineering” (issued by Technical Shoin in May 1993), the braking distance of a general vehicle is calculated as follows.
Braking distance Y = V ² / (2 × g × μ)
Where V: travel speed (km / hour), Y: braking distance (m), g: gravitational acceleration (9.8 m / s ² ), μ: friction coefficient.
The friction coefficient μ is a coefficient according to the road surface condition, μ = 0.70 for dry asphalt, μ = 0.45 to 0.60 for wet asphalt, and μ = 0 for concrete. .50, μ = 0.55 for gravel roads, μ = 0.15 for solid snow roads, and μ = 0.07 for ice.
Therefore, assuming that μ = 0.7 when the vehicle traveling speed V is 50 km / hour, the braking distance Y is 14 m, and when the vehicle traveling speed V is 80 km / hour, μ = 0.7. Assuming that the braking distance Y is 36 m.

  Therefore, when the traveling vehicle 2 detects the stopped vehicle 2 ahead, in order to stop without colliding with the stopped vehicle 2, for example, the traveling speed V of the traveling vehicle 2 is 50 km / hour (13.8 m / second). In this case, it is necessary to perform deceleration control from the stopped vehicle 2 to 14 m or more before. In other words, in order to realize the platooning with the traveling speed V of 50 km / hour (13.8 m / second), it means that the traveling vehicle 2 needs to detect the stopped vehicle 2 before 14 m or more. All the vehicles 2 need to notify the other vehicles 2 in the vicinity of the position information of the own vehicle 2 in a cycle of about 1 second. Actually, in consideration of a delay time and a safety factor caused by various processes such as a vehicle position calculation process, a wireless communication process, and a vehicle control, a period of 1 second or less such as a period of several hundred milliseconds is considered appropriate.

  Therefore, in the present embodiment, in the leading vehicle 2-1 (see FIG. 1) traveling in a platoon, the wireless transmission frame is set at, for example, 100 milliseconds as the wireless transmission cycle W (the time length of the wireless transmission period T shown in FIG. 3). 300 is transmitted, and the data link unit 103 manages the wireless transmission cycle W.

FIG. 6 is a block diagram showing a functional configuration for managing the radio transmission cycle W among the functional configurations of the data link unit 103. As shown in this figure, the data link unit 103 includes a host vehicle transmission monitoring unit 601, a counter unit 602, and a comparison determination unit 603.
The own vehicle transmission monitoring unit 601 detects the transmission start of the wireless transmission frame 300 of the own vehicle 2 (that is, the start timing of the wireless communication period TA) and outputs a count start signal to the counter unit 602. . At this time, the own vehicle transmission monitoring unit 601 may detect the transmission start of the wireless data unit 302 of the wireless transmission frame 300.

  The counter unit 602 is a counter for counting the respective timings of the wireless communication suspension period TB and the wireless channel monitoring period TC based on a clock signal of a clock circuit (not shown) built in the wireless communication apparatus 11. When the count start signal is input from the own vehicle transmission monitoring unit 601, the counter unit 602 clears the counter value, counts up the counter from the initial value, and starts counting. Thereby, the count operation is started from the start timing of the wireless transmission of the own device.

  The comparison determination unit 603 compares the counter value of the counter unit 602 with a predetermined radio transmission cycle W (here, 100 milliseconds), detects the radio transmission timing Ts, and controls radio transmission such as the CPU 101, for example. A wireless transmission start signal is output to each unit. As a result, in the head vehicle 2 traveling in a row, the travel information of the host vehicle 2 is transmitted to other vehicles 2 at time intervals of the wireless transmission period W. In the second and third vehicles 2 from the head, the wireless transmission frame 300 transmitted by the head vehicle 2 is received, and according to the above procedure, it is relative distance from the head vehicle 2. By setting the wireless channel monitoring period TC corresponding to the wireless transmission, wireless transmission is started one by one in order.

The wireless communication between the vehicles 2 in one platoon has been described above, but the wireless communication when a plurality of platoons travel will be described below.
For example, on roads with multiple lanes, such as highways, or roads with both up and down lanes, multiple platoons may travel on each lane. In an interchange, another platoon may run in the vicinity of a certain platoon. In such a case, if no measures are taken, radio communication interference may occur between the platoons, and the stable radio communication environment may be hindered.
Therefore, in the present embodiment, the wireless communication device 11 is configured to perform frequency multiplex communication such as frequency division or code division, and a wireless channel is assigned in advance to each lane of the traveling route, so that each vehicle 2 travels while traveling. By configuring wireless communication using the wireless channel assigned to the route, stable wireless communication can be maintained between each vehicle 2 in the platoon even when multiple platoons run close together. It is said. Hereinafter, this configuration will be described in detail by taking an expressway as an example.

FIG. 7 is a diagram schematically showing an expressway, and FIG. 8 is a diagram showing an example of assignment of radio channels used on the expressway.
As shown in FIG. 7, the two highways (travel routes) H1 and H2 are each configured to have an up lane R1 and a down lane R2, and each highway H1 and H2 is shown in FIG. As described above, individual radio channels CH1 to CH4 are assigned in advance to the respective lanes R1 and R2. In the following description, the lanes R1 and R2 are denoted by the reference symbol R when there is no particular need to distinguish them, and the wireless channels CH1 to CH4 are similarly denoted by the reference symbol CH.

The assignment of the radio channel CH is stored in the vehicle control device 12 in advance, and the vehicle control device 12 specifies the radio channel CH of the lane R that is running based on the own vehicle position output from the car navigation device 13. The wireless communication apparatus 11 is configured to control the wireless communication using the wireless channel CH. Thereby, when each vehicle 2 constituting the platoon performs wireless communication, wireless communication is performed using the wireless channel CH assigned to the lane R on which the platoon travels, and a plurality of platoons travel in close proximity. Even so, it is possible to prevent radio communication interference between the convoys traveling in different lanes R.
A configuration in which the assignment of the radio channel CH is stored in the car navigation device 13 in advance, and the car navigation device 13 specifies the radio channel CH of the lane R that is running based on the vehicle position and outputs it to the vehicle control device 12. It is also good.

Next, a case where the vehicle 2 of a certain platoon changes the route will be described with reference to FIG. 7 as an example where the vehicle 2 changes the route from the upstream lane R1 of the highway H1 to the upstream lane R1 of the highway H2. To do.
As shown in this figure, the ascending lane R1 of the highway H1 is branched at the bifurcation B and merged with the ascending lane R1 of the expressway H2 at the junction J. In this embodiment, When the vehicle 2 changes the route, that is, the lane R, the wireless channel CH used for wireless communication is switched in the section K from the branching section B to the joining section J.

  More specifically, when the vehicle 2 traveling on the up lane R1 of the highway H1 branches off from the up lane R1 at the branch B, the car navigation device 13 detects such a branch based on the detection of the vehicle position. The vehicle control device 12 is notified of the upstream lane R1 of the junction highway H2. When the lane R of the merge destination is notified from the car navigation device 13, the vehicle control device 12 specifies the radio channel CH assigned to the lane R and wirelessly communicates using the radio channel CH. The communication device 11 is controlled. Thereby, when the vehicle 2 branches from the branch part B, switching of the radio channel CH is performed.

  Here, in the section K from the branch B to the junction J, the vehicle 2 wirelessly communicates on the radio channel CH1 assigned to the up lane R1 of the highway H1 and the up lane R1 of the highway H2. The vehicle 2 that communicates wirelessly through the wireless channel CH3 is mixed.

Therefore, in the present embodiment, when the vehicle 2 passes through the branch portion B and switches from the radio channel CH1 to the radio channel Ch3, at least until the vehicle 2 passes through the junction portion J, that is, the vehicle 2 is on the highway H2. Until the lane change to the up lane R1 is completed, the radio communication device 11 switches the radio channel CH1 before switching and the radio channel CH3 after switching in a time-sharing manner, so that both radio channels CH1, Wireless communication is performed using CH3.
Thereby, also in the section K from the branch part B to the junction part J, the radio | wireless communication between each vehicle 2 is attained, and the stable radio | wireless communication environment can be implement | achieved. In addition, since wireless communication is possible with the vehicle 2 traveling on the lane R1 that is the merging destination while traveling in the section K, safety at the time of merging can be ensured.

In addition, after the vehicle 2 passes the junction part J, until it travels a predetermined distance (for example, 200M (meter)), it is possible to continue the wireless communication in both the wireless channels CH1 and CH3 before and after the switching. desirable.
In addition, the wireless communication device 11 includes a first wireless communication unit for performing wireless communication using the wireless channel CH1 before switching, and a second wireless communication unit for performing wireless communication using the wireless channel CH3 after switching. Two wireless communication means may be provided, and wireless communication may be performed on both wireless channels CH before and after switching using the first and second wireless communication means.

  Thus, according to the present embodiment, the radio channel CH is assigned to each lane R, and each of the radio communication devices 11 of each vehicle 2 uses the radio channel CH assigned to the traveling lane R. Since it is configured to perform wireless communication, it is possible to prevent wireless communication interference between vehicles 2 in separate fleets running in other lanes R.

  Further, according to the present embodiment, when the vehicle 2 changes the lane R in order to change the travel route (highway), the wireless communication device 11 mounted on the vehicle 2 has at least the lane R. Until the change is completed, the wireless communication is performed using both radio channels CH assigned to the lane R before the change and the lane R after the change. Stable wireless communication between both the vehicle 2 in the lane R and the vehicle 2 in the changed lane R can be maintained, and stable wireless communication can be continuously maintained even after the lane change. it can.

  Further, according to the present embodiment, when the wireless communication device 11 of each vehicle 2 constituting one platoon transmits a wireless transmission frame (transmission data) 300 for platooning, the other wireless communication device 11 When the wireless transmission frame 300 including the current position of the other vehicle 2 is received, a wireless channel monitoring period TC having a time length corresponding to the relative distance between the other vehicle 2 and the host vehicle 2 is set, and the wireless channel Since the wireless transmission frame 300 is transmitted when the monitoring period TC elapses, the transmission timings can be made different among the plurality of wireless communication devices 11, so that each wireless communication device 11 does not go through a base station or the like. Even when wireless communication is performed directly with each other, collision of wireless signals can be prevented.

  In particular, when each of the wireless communication devices 11 receives a new wireless transmission frame 300 before the wireless channel monitoring period TC elapses, when the new wireless transmission frame 300 is received, the new wireless transmission frame 300 Since the radio channel monitoring period TC having a time length corresponding to the relative distance between the vehicle 2 that transmitted the frame 300 and the host vehicle 2 is newly set, it is possible to reliably avoid collision of radio signals. In addition, it is possible to prevent a situation in which the specific wireless communication device 11 cannot always transmit.

  Further, according to the present embodiment, when each of the wireless communication devices 11 receives the wireless transmission frame 300 including the current position of the other vehicle 2 from the other wireless communication device 11, the other vehicle 2 When the vehicle is located behind the traveling direction, the transmission of the wireless transmission frame 300 is prohibited. Therefore, an opportunity for wireless transmission is given one by one in order from the leading vehicle 2 along the traveling direction.

  Further, according to the present embodiment, the wireless communication device 11 is configured to transmit the wireless transmission frame 300 at a predetermined wireless transmission cycle W when there is no other vehicle 2 ahead in the traveling direction. The wireless communication between the vehicles 2 can be repeated cyclically, and the traveling information between the vehicles 2 can be intermittently received.

The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention.
For example, in the above-described embodiment, the vehicle 2 is configured to acquire the travel position and travel status (vehicle speed and travel direction) of the host vehicle from the car navigation device 13, but the present invention is not limited to this, and a vehicle speed sensor, a gyro sensor, or the like. It is good also as a structure acquired using these various sensors.

For example, in the above-described embodiment, the radio channel CH assigned to the lane R is stored in the vehicle control device 12 or the car navigation device 13 in advance. It is good also as a structure which arrange | positions and the radio | wireless channel CH with which the said route side communication apparatus was allocated to the lane R is notified to the vehicle 2 which drive | works the said lane R by road-to-vehicle radio communication.
Specifically, as shown in FIG. 9, in a route configuration in which a lane R2 merges with a lane R1 at a junction J, a roadside wireless device is placed on the road in the lane R2 before the junction J (for example, 200M). (Route side communication device) 700 is arranged, and the radio channel CH of the lane R1, which is the merge destination, is transmitted from the roadside radio 700 to the vehicle 2 traveling on the lane R2, and this radio channel CH is received. The vehicle 2 side switches the radio channel CH.
Thereby, even when the vehicle 2 side does not have the allocation data of the radio channel CH for each lane R, the radio channel CH to be used for inter-vehicle communication can be notified to the traveling vehicle 2. It becomes. Further, the radio channel CH assigned to the lane R can be dynamically changed.

When a plurality of lanes R are included in the route, it is desirable that the roadside radio 700 transmits a radio channel CH for each lane R, and an area (for example, coordinates) where the use of the radio channel CH is started. May also be configured to transmit together.
Further, the present invention is not limited to the configuration in which the roadside wireless device 700 is used for merging the lane R1 and the lane R2, but can be used for branching. Furthermore, for example, when the assignment of the radio channel CH is changed only for a predetermined section in the lane R1 due to construction, or when a new route (lane) is formed, the roadside radio 700 is used, Since it is possible to notify the vehicle 2 of the wireless channel CH to be used for wireless communication, the assignment of the wireless channel CH to the lane R can be easily changed.

It is a figure which shows the structure of the communication system between vehicles which concerns on embodiment of this invention. It is a block diagram which shows the functional structure of a radio | wireless communication apparatus. It is a timing chart which shows the transmission timing with the structure of a radio | wireless transmission frame. It is a block diagram which shows the functional structure of a data link part. It is a timing chart which shows the transmission operation | movement of a radio | wireless transmission frame. It is a block diagram which shows the functional structure of a data link part. It is a figure for demonstrating the radio | wireless communication at the time of lane merge in a highway. It is a figure which shows allocation of the radio channel for every lane. It is a figure for demonstrating the notification of the radio channel using a roadside radio | wireless machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inter-vehicle communication system 2 Vehicle 11 Radio | wireless communication apparatus 12 Vehicle control apparatus 13 Car navigation apparatus 103 Data link part 300 Wireless transmission frame 700 Road side radio | wireless machine (route side communication apparatus)
A wireless communication area L distance between vehicles T wireless transmission period TA wireless communication period TB wireless communication suspension period TC wireless channel monitoring period Ts wireless transmission timing CH wireless channel

Claims (9)

In a vehicle-to-vehicle communication system having a plurality of vehicles equipped with wireless communication devices and transmitting and receiving transmission data between the respective wireless communication devices,
Assign a wireless channel for each lane,
Each of the wireless communication devices of each vehicle performs wireless communication using a wireless channel assigned to a traveling lane. When the vehicle changes lanes, the wireless communication device mounted on the vehicle wirelessly uses radio channels assigned to the lane before the change and the lane after the change until the lane change is completed. The inter-vehicle communication system according to claim 1, wherein communication is performed. Each of the vehicles
Position detecting means for detecting the current position of the host vehicle;
Radio channel specifying means for specifying a radio channel assigned to the lane based on the current position detected by the position detecting means;
3. The inter-vehicle communication system according to claim 1, wherein each of the wireless communication devices performs wireless communication using a wireless channel specified by the wireless channel specifying unit. The inter-vehicle communication system according to claim 1 or 2, wherein a route-side communication device that transmits a radio channel assigned to the lane to a vehicle traveling in the lane is disposed on the road. Each of the vehicles
Having position detecting means for detecting the current position of the host vehicle;
Each of the wireless communication devices
While transmitting the transmission data including the current position of the vehicle,
When the transmission data is received from the wireless communication device of another vehicle, the current position of the own vehicle is transmitted at the timing when the time corresponding to the relative distance between the other vehicle and the own vehicle has elapsed from the timing of the reception. The inter-vehicle communication system according to claim 1, wherein the inter-vehicle communication system is transmitted. Each of the wireless communication devices
New transmission data is received from the time when the transmission data including the current position of the other vehicle is received from another wireless communication device until the time corresponding to the relative distance between the other vehicle and the host vehicle has elapsed. The transmission data is transmitted when a time corresponding to the relative distance between the vehicle that has transmitted the new transmission data and the host vehicle has elapsed from the timing at which the new transmission data is received. The inter-vehicle communication system according to claim 5, Each of the wireless communication devices
When transmission data including the current position of another vehicle is received from another wireless communication device, transmission of the transmission data is prohibited when the other vehicle is located behind the own vehicle in the traveling direction. The inter-vehicle communication system according to claim 5 or 6. The inter-vehicle communication system according to any one of claims 1 to 7, wherein each of the vehicles travels in a row based on the transmission data transmitted from each of the wireless communication devices. In a wireless communication device mounted on a vehicle and transmitting / receiving transmission data to / from a wireless communication device mounted on another vehicle,
A wireless communication apparatus that acquires a wireless channel assigned to a lane in which a vehicle is traveling and performs wireless communication using the wireless channel.

Images