JP2009239583A - Inter-vehicle communication method and inter-vehicle communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inter-vehicle communication method associated with access control over inter-vehicle communication. <P>SOLUTION: The inter-vehicle communication method is provided for each of a plurality of vehicles in which information on vehicles belonging to respective groups of a plurality of vehicles is exchanged between the vehicle groups. The inter-vehicle communication method includes: a position detection step of detecting the position of the vehicle; an area detection step of detecting an area in which the vehicle is from one or a plurality of predetermined areas based upon the position of the vehicle detected in the position detection step; an area information addition step of adding information on the area detected in the area detection step to information on the vehicle or vehicle group when the vehicle transmits the information on the vehicle or vehicle group; and a data selection step of acquiring only the information on the vehicle or vehicle group to which the information on the area detected in the area detection step is added when the vehicle receives the information on the vehicle or vehicle group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inter-vehicle communication method and an inter-vehicle communication apparatus. In particular, the present invention relates to an inter-vehicle communication (IVC) system applicable to an advanced safety vehicle (ASV) and the like that are being developed for the purpose of improving safety.

  Recently, attention has been focused on a technology called inter-vehicle communication (IVC) in which vehicles directly communicate with each other without using an infrastructure such as a roadside device using an autonomous distributed control type wireless communication technology. The IVC is applied to, for example, ASV and is intended to provide a safe driving support service, an entertainment information service, and the like when the vehicle is traveling. In this regard, for example, the following Non-Patent Document 1 describes a DSRC (Dedicated Short Range Communications) type IVC system.

  In the document 1, as a request for communication characteristics required for a DSRC type IVC system, high speed, large capacity, high quality, a wide service area, and high mobility are listed. In addition, in the DSRC type IVC system, it is required to promptly exchange information with a vehicle that enters the service area around the own vehicle or leaves the service area. Therefore, high real-time properties are also required for the above communication characteristics.

  Note that DSRC is short-range short-term communication used in ETC (Electronic Toll Collection System) and the like. However, the IVC system may use a communication band such as UHF (Ultra High Frequency) in addition to the DSRC. Therefore, technological development for realizing the above-described communication characteristics by efficiently using such a plurality of communication bands has been energetically advanced.

Tokuda Kiyohito, “Realization of safety applications in a ubiquitous network environment by DSRC inter-vehicle communication system”, Oki Technical Review, October 2004 / No. 200, Vol. 71, no. 4 (http://www.oki.com/jp/Home/JIS/Books/KENKAI/n200/pdf/200_R07.pdf)

  With respect to the above-described technology, a problem has been pointed out that the number of vehicles that can simultaneously receive services is limited depending on the frequency band used. In order to solve this problem, for example, the following method capable of realizing the above-described communication characteristics required for the provided service while maintaining a predetermined communication quality has been proposed.

  In this method, a group (hereinafter referred to as a vehicle group) is formed by a plurality of vehicles, and communication between the vehicle groups is executed by a vehicle (hereinafter referred to as a master) selected in the vehicle group. That is, the vehicle group communication method. In this vehicle group communication method, for example, information on vehicles in the first vehicle group is transmitted to a second vehicle group different from the first vehicle group by the master of the first vehicle group. The master of the second vehicle group receives vehicle information in the first vehicle group. That is, in the vehicle group communication method, information on vehicles belonging to each vehicle group is exchanged between masters of each vehicle group.

  In this way, instead of communicating each vehicle information individually between vehicles, the communication across the vehicle groups is replaced with vehicle group-to-vehicle group communication (hereinafter, vehicle group communication) via the master. is there. That is, communication between vehicles is divided into communication between vehicles in a vehicle group (hereinafter referred to as in-vehicle communication) and communication between vehicle groups, and the use efficiency of the frequency band is improved. As a result, the number of vehicles that can use a predetermined service at the same time increases, and the overall capacity can be increased.

  However, when a service is provided by intra-car group communication or inter-car group communication, an area in which a predetermined service is provided (hereinafter referred to as a service area) and an area in which vehicles can communicate (hereinafter referred to as a communication area) There is a case where the service area is narrower than the communication area. In that case, if there are a plurality of service areas in the communication area, information of services unnecessary for the host vehicle is received, and a process of discarding them is necessary. However, as described above, the safe driving support system is required to have a high real-time property, and such redundant processing is not preferable. In particular, a processing method that analyzes the contents of vehicle information in an upper layer such as an application and determines whether or not the service information is necessary for the host vehicle takes too much time and does not realize high real-time performance. There was a problem.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to add information on a service area to a vehicle or a group of vehicles existing in a plurality of service areas and transmit the information. To provide a new and improved vehicle-to-vehicle communication method and vehicle-to-vehicle communication device capable of efficiently determining whether or not the information of the vehicle or vehicle group that has received the information is necessary for the host vehicle. It is in. In addition, by multiplexing and transmitting such vehicle and vehicle group information, it is possible to determine whether the information is related to the service required for the host vehicle in a lower layer that performs communication control, thereby realizing high real-time performance. Is an issue.

  (1) In order to solve the above problems, according to an aspect of the present invention, there is provided the following inter-vehicle communication method by each of the vehicles belonging to a vehicle group formed of a plurality of vehicles. In this inter-vehicle communication method, the position of the host vehicle is detected from one or a plurality of predetermined areas based on the position detection step in which the position of the host vehicle is detected, and the position of the host vehicle detected in the position detection step. An area detection step in which an included area is detected; an area information addition step in which information on the area detected in the area detection step is added to the information when the information is transmitted by the own vehicle; And a data selection step of selecting only information to which the information of the area detected in the area detection step is added when the information is received.

  (2) Further, in the above-described inter-vehicle communication method, when a plurality of areas are detected in the area detecting step, the information on vehicles or vehicle groups existing in the plurality of areas is multiplexed by a frame configuration. It may be configured to further include a step.

  (3) Further, the inter-vehicle communication method is configured such that the transmission / reception frequency used for transmitting / receiving the information further includes a frequency setting step in which a frequency is set for each area detected in the area detection step. Also good. In this case, in the multiplexing step, information on the vehicles or vehicle groups existing in the plurality of areas is multiplexed according to the frequency or the frame configuration according to the frequency set in the frequency setting step.

  (4) Moreover, regarding any one of the vehicle-to-vehicle communication methods described above, in the area information adding step, intersection location information may be used as the area information.

  (5) Moreover, in order to solve the said subject, according to another viewpoint of this invention, the following inter-vehicle communication methods by each said vehicle which belongs to the vehicle group formed with the several vehicle are provided. In this inter-vehicle communication method, the position of the host vehicle is detected from one or a plurality of predetermined areas based on the position detection step in which the position of the host vehicle is detected, and the position of the host vehicle detected in the position detection step. An area detection step in which the included area is detected; a transmission / reception frequency used for transmission / reception of information includes a frequency setting step in which a frequency is set for each area detected in the area detection step; and a plurality of areas in the area detection step. A multiplexing step in which, when the area is detected, information on vehicles or vehicle groups existing in the plurality of areas is multiplexed according to the frequency according to the frequency set in the frequency setting step. It is a feature.

  (6) Moreover, in order to solve the said subject, according to another viewpoint of this invention, the following inter-vehicle communication apparatuses provided in each said vehicle of the vehicle group formed with the several vehicle are provided. . The inter-vehicle communication device includes a position detection unit that detects a position of the host vehicle, and a position of the host vehicle from one or a plurality of predetermined areas based on the position of the host vehicle detected by the position detection unit. Area detecting means for detecting the area to be detected, area information adding means for adding information on the area detected by the area detecting means to the information when the information is transmitted by the own vehicle, and information received by the own vehicle. And a data selection means for selecting only the information to which the area information detected by the area detection means is added.

  (7) Further, the inter-vehicle communication device described above multiplexes, when a plurality of areas are detected by the area detecting means, information on vehicles or vehicle groups existing in the plurality of areas is multiplexed by a frame configuration. Means may be further provided.

  (8) Further, the inter-vehicle communication device is configured to further include a frequency setting unit that sets a transmission / reception frequency used for transmission / reception of the previous information to a frequency for each area detected by the area detection unit. Also good. In this case, the multiplexing means is configured to multiplex information of vehicles or vehicle groups existing in the plurality of areas by frequency or frame configuration in accordance with the frequency set by the frequency setting means. .

  (9) Moreover, regarding any one of the vehicle-to-vehicle communication devices described above, the area information adding means may be configured to use intersection position information as the area information.

  (10) Moreover, in order to solve the said subject, according to another viewpoint of this invention, the following inter-vehicle communication apparatuses provided in each said vehicle of the vehicle group formed with the several vehicle are provided. . The inter-vehicle communication device includes a position detection unit that detects a position of the host vehicle, and a position of the host vehicle from one or a plurality of predetermined areas based on the position of the host vehicle detected by the position detection unit. An area detecting means for detecting the area, a frequency setting means for setting a transmission / reception frequency used for transmitting / receiving information to a frequency for each area detected by the area detecting means, and a plurality of the areas by the area detecting means. And a multiplexing unit that multiplexes the information of the vehicles or vehicle groups existing in the plurality of areas by the frequency according to the frequency set by the frequency setting unit when detected. It is.

  As described above, according to the present invention, by adding the information on the service area to the information on the vehicle or vehicle group existing in a plurality of service areas and transmitting the information, the information on the vehicle or vehicle group that has received the information is transmitted. It is possible to efficiently determine whether or not the host vehicle is necessary. In addition, by multiplexing and transmitting such vehicle and vehicle group information, it is possible to determine whether the information is related to the service required for the host vehicle in a lower layer that performs communication control, thereby realizing high real-time performance. Can do.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[Functional Configuration of Conventional Inter-Vehicle Communication Device 10]
First, prior to describing a preferred embodiment of the present invention, a functional configuration of a conventional inter-vehicle communication device 10 will be briefly described in order to clarify a comparison relationship with the technology according to the embodiment. FIG. 1 is an explanatory diagram showing a functional configuration of a conventional inter-vehicle communication device 10.

  As shown in FIG. 1, the inter-vehicle communication device 10 mainly includes a service control unit 12, a vehicle group control unit 14, and an inter-vehicle communication unit 16.

(Service control means 12)
The service control means 12 is means for generating information (hereinafter referred to as notification information) to be notified to other vehicles in order to provide a predetermined service. This notification information includes information such as the position and speed of the host vehicle, or information generated by the service control means 12 regarding a predetermined service. As a specific example of the predetermined service, for example, a service for warning that another vehicle is approaching the host vehicle is conceivable.

  On the other hand, the service control unit 12 first obtains notification information generated by another vehicle (that is, information such as the position and speed of the other vehicle, or information generated regarding a predetermined service) (hereinafter, other vehicle information). To do. This other vehicle information is acquired by the inter-vehicle communication means 16 and is input to the service control means 12 via the data processing means 22. Moreover, the service control means 12 determines whether the own vehicle and the other vehicle are approaching based on other vehicle information. When the distance between the vehicles is approaching, the service control means 12 warns the driver as necessary.

  Not limited to this example, the service control unit 12 acquires other vehicle information, performs processing necessary for a predetermined service based on the other vehicle information, and generates information to be notified to the other vehicle. This notification information is transmitted to other vehicles via the data processing means 22 and the inter-vehicle communication means 16.

(Vehicle group control means 14)
The vehicle group control unit 14 includes a data processing unit 22 and a vehicle group formation unit 24.

(Data processing means 22)
The data processing unit 22 is a unit that selects a vehicle to which the notification information generated by the service control unit 12 is to be transmitted, or selects a vehicle to be acquired from other vehicle information. Notification information is input to the data processing means 22 by the service control means 12. Further, the data processing unit 22 receives information on a vehicle group to which the host vehicle belongs and information on vehicles included in the vehicle group by a vehicle group formation unit 24 described later.

  First, a case where notification information is transmitted will be described. Depending on the type of service provided by the service control unit 12, the data processing unit 22 determines whether the transmission destination of the notification information should be a vehicle in the vehicle group or all vehicles including those outside the vehicle group. to decide. At this time, the data processing means 22 makes a determination according to whether the host vehicle is a master in the vehicle group. For example, when the host vehicle is the master selected in the vehicle group, depending on the type of the notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups are also set as the transmission destination of the notification information. Need to be included in the vehicle. Through such a determination, the transmission destination of the notification information is designated and input to the inter-vehicle communication means 16.

  Next, reception of notification information transmitted from another vehicle will be described. Depending on the type of service provided by the service control unit 12, the data processing unit 22 should send the notification information to be received to a vehicle in the vehicle group or to all vehicles including those outside the vehicle group. Determine what to do. At this time, the data processing means 22 makes a determination according to whether the host vehicle is a master in the vehicle group. For example, if the host vehicle is the master selected in the vehicle group, depending on the type of notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups also receive notification information to be received. It needs to be included in the sender. After such determination, the transmission source of the notification information to be received is designated and input to the inter-vehicle communication means 16.

(Car group forming means 24)
The vehicle group formation means 24 is used to form a vehicle group by one or a plurality of vehicles existing around the own vehicle, to enter an already formed vehicle group, or to leave the entered vehicle group. Means. Moreover, the vehicle group formation means 24 sets the master for performing communication between vehicle groups among the vehicles which belong to a vehicle group. For example, the vehicle group forming means 24 sets the vehicle that first formed the vehicle group as the master. Further, when the vehicle set as the master leaves, the vehicle group forming means 24 sets the vehicle that has entered next to the separated vehicle as the master.

  Furthermore, the vehicle group formation means 24 sets the attribute of the vehicle which is not set to the master among the vehicles which belong to a vehicle group to a slave. With this setting, the state of each vehicle is classified into three types of attributes: master, slave, and outside the vehicle group. In the following description, these three types of attributes are referred to as vehicle states. Information indicating the state of the host vehicle set by the vehicle group formation unit 24 (hereinafter, state information) is input to the data processing unit 22. Note that the transmission destination or transmission source of the notification information is selected based on this state information.

(Vehicle communication means 16)
The vehicle-to-vehicle communication unit 16 adds information necessary for access control to the notification information input from the data processing unit 22 to generate a frame. This frame is modulated at a predetermined frequency and transmitted to the destination vehicle selected by the data processing means 22. On the other hand, the inter-vehicle communication means 16 receives the modulation signal of the notification information transmitted at a predetermined frequency from the transmission source selected by the data processing means 22 and demodulates the frame. Further, the inter-vehicle communication unit 16 removes information necessary for access control from the demodulated frame and inputs the information to the data processing unit 22.

  The functional configuration of the conventional inter-vehicle communication device 10 has been described above. As described above, the inter-vehicle communication device 10 can control formation of a vehicle group or entry / exit from the vehicle group. In addition, a vehicle state such as a master is set in the formed vehicle group. Furthermore, a transmission destination of notification information necessary for providing a service or a transmission destination of notification information to be received is set according to the state of the host vehicle. Between vehicles equipped with such an inter-vehicle communication device 10, a vehicle group is formed as necessary, and communication within the vehicle group and communication between the vehicle groups are hierarchized. Therefore, the frequency utilization efficiency when information is transmitted and received between vehicles is improved, and the number of vehicles that can be accommodated in a predetermined frequency band is increased.

  However, when a service is provided by intra-car group communication or inter-car group communication, an area in which a predetermined service is provided (hereinafter referred to as a service area) and an area in which vehicles can communicate (hereinafter referred to as a communication area) There is a case where the service area is narrower than the communication area. In that case, if there are a plurality of service areas in the communication area, information of services unnecessary for the host vehicle is received, and a process of discarding them is necessary. However, as described above, the safe driving support system is required to have a high real-time property, and such redundant processing is not preferable. In particular, a processing method that analyzes the contents of vehicle information in an upper layer such as an application and determines whether or not the service information is necessary for the host vehicle takes too much time and does not realize high real-time performance. There's a problem. Applying the technique of the embodiment described below solves these problems.

<First Embodiment>
First, a first embodiment of the present invention will be described. In the present embodiment, a vehicle group is formed by a plurality of vehicles, a master is selected from the vehicles in the vehicle group, and information on vehicles belonging to the vehicle group is transferred between the vehicles belonging to other vehicle groups by the master. It is related with the communication method between vehicles for exchanging in. In particular, there is a feature in a configuration in which information on a service area where a vehicle group is formed is added to vehicle information or vehicle group information and transmitted. Furthermore, the configuration is characterized in that information of a plurality of service areas is multiplexed by frequency.

[Functional configuration of inter-vehicle communication device 100]
A functional configuration of the vehicle-to-vehicle communication device 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a functional configuration of the inter-vehicle communication device 100 according to the present embodiment.

  As shown in FIG. 2, the inter-vehicle communication device 100 is mainly configured by a service control unit 102, a vehicle position detection unit 104, a frequency setting unit 106, an inter-vehicle communication unit 108, and a vehicle group control unit 130. The

(Service control means 102)
The service control unit 102 is a unit that generates notification information in order to provide a predetermined service. This notification information includes information such as the position and speed of the host vehicle, or information generated by the service control means 102 to provide a predetermined service. For example, the service control unit 102 obtains other vehicle information, and performs processing necessary for a predetermined service based on the other vehicle information to generate notification information. This notification information is transmitted to other vehicles by the inter-vehicle communication means 108.

  In addition, the service control unit 102 inputs information indicating the range of a service area where a predetermined service is provided (hereinafter, area range information) to the area detection unit 138. Note that the function of the service control unit 102 is realized by using resources such as the central processing unit H14 and the memory H16 in a hardware configuration to be described later. For example, the position / range of the service area may be stored in the memory H16 as absolute position information expressed by latitude and longitude. At this time, together with the service area information, the contents of the service provided in the area may be stored in association with the memory H16.

(Vehicle position detection means 104)
The vehicle position detection unit 104 detects the position of the host vehicle. The vehicle position detection unit 104 detects an absolute position expressed by latitude and longitude, for example. The information on the absolute position detected by the vehicle position detection unit 104 is input to the area detection unit 138 described later. Note that the function of the vehicle position detection unit 104 is realized by using resources such as a GPS receiver H12 in a hardware configuration described later, for example.

(Frequency setting means 106)
The frequency setting means 106 sets a transmission / reception frequency used when information is transmitted / received in intra-vehicle group communication and inter-vehicle group communication. The information on the transmission / reception frequency set by the frequency setting means 106 is input to the vehicle-to-vehicle communication means 108 described later. Hereinafter, a frequency used for intra-vehicle communication may be referred to as an intra-vehicle frequency, and a frequency used for inter-vehicle communication may be referred to as an inter-vehicle frequency. The in-vehicle group frequency and the inter-vehicle group frequency are determined by the service area detected by the area detecting unit 138. Note that the function of the frequency setting means 106 is realized by using resources such as a communication control unit H18, a central processing unit H14, and a memory H16 in a hardware configuration to be described later.

(Vehicle communication means 108)
The inter-vehicle communication unit 108 generates a frame by adding information necessary for access control to the notification information input from the data selection unit 152. This frame is modulated by a predetermined modulation method, modulated at the transmission frequency set by the frequency setting means 106, and periodically transmitted.

  Further, the inter-vehicle communication unit 108 receives the modulation signal at the reception frequency set by the frequency setting unit 106 and demodulates the frame from the modulation signal. Furthermore, the vehicle-to-vehicle communication unit 108 removes information necessary for access control from the demodulated frame, and extracts notification information of other vehicles included in the frame. The notification information extracted by the inter-vehicle communication unit 108 is input to the data selection unit 152.

  Note that the function of the vehicle-to-vehicle communication means 108 is realized by using resources such as the communication control unit H18 and the RF front-end circuit H20 in the hardware configuration described later.

(Vehicle group control means 130)
The vehicle group control unit 130 includes a data processing unit 132, a data selection unit 152, a vehicle group formation unit 134, and an area detection unit 138. The function of the vehicle group control means 130 is realized by using resources such as a central processing unit H14, a memory H16, and a communication control unit H18 in a hardware configuration described later.

(Data processing means 132)
The data processing unit 132 has a function of selecting a transmission destination vehicle to which the notification information generated by the service control unit 102 should be transmitted and a source of the notification information to be received. Notification information is input to the data processing unit 132 by the service control unit 102. Further, the data processing unit 132 receives information on a vehicle group to which the host vehicle belongs, information on a vehicle included in the vehicle group, status information on the host vehicle, and the like by a vehicle group forming unit 134 described later.

  First, a case where notification information is transmitted will be described. Based on the type of service provided by the service control unit 102, information on the own vehicle / other vehicle, etc., the data processing unit 132 should send the notification information to a vehicle in the vehicle group, or outside the vehicle group Judge what should be the next vehicle. In particular, the determination by the data processing unit 132 depends on the state information of the host vehicle. For example, when the host vehicle is the master selected in the vehicle group, depending on the type of the notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups are also set as the transmission destination of the notification information. Need to be included in the vehicle. Through this determination, the transmission destination of the notification information is designated and input to the vehicle-to-vehicle communication unit 108 via the data selection unit 152. The method for selecting a transmission destination will be described in detail later.

  Next, reception of notification information transmitted from another vehicle will be described. Based on the type of service provided by the service control unit 102, information on the own vehicle / other vehicle, etc., the data processing unit 132 should set the transmission source of the notification information to be received to a vehicle in the vehicle group, or Determine whether the vehicle should be outside the vehicle group. In particular, the determination by the data processing unit 132 depends on the state information of the host vehicle.

  For example, if the host vehicle is the master selected in the vehicle group, depending on the type of notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups also receive notification information to be received. It needs to be included in the sender. After such determination, the transmission source of the notification information to be received is designated and input to the inter-vehicle communication unit 108 via the data selection unit 152. A method for selecting a transmission destination of information to be received will be described in detail later.

(Data selection means 152)
The data selection unit 152 acquires information (hereinafter referred to as area information) related to the service area where the host vehicle is present from the area detection unit 138. Then, the data selection unit 138 adds the acquired area information to the notification information input via the data processing unit 132. The notification information to which the area information is added is input to the vehicle-to-vehicle communication means 108.

  On the other hand, when the notification information from the other vehicle received by the inter-vehicle communication unit 108 is input, the data selection unit 152 refers to the area information added to the notification information, and within the service area where the host vehicle is located. Only the notification information about the vehicle or the vehicle group is selected. The selected notification information is input to the data processing unit 132.

(Car group forming means 134)
The vehicle group forming means 134 forms a vehicle group with the own vehicle, causes the own vehicle to enter the already formed vehicle group, or causes the own vehicle to leave the vehicle group. Further, the vehicle group forming means 134 sets the state of the host vehicle. There are basically three types of vehicle status: master, slave, and outside the vehicle group. Then, the state of the host vehicle set by the vehicle group forming unit 134 is input to the data processing unit 132. The vehicle group forming means 134 manages entry and exit from the vehicle group, particularly when the host vehicle is a master.

(Area detection means 138)
The area detection unit 138 is based on the position information of the host vehicle input from the vehicle position detection unit 104 and information indicating the range of the service area input from the service control unit 102 (hereinafter, area range information). It is detected whether or not the position of the host vehicle is included in the service area indicated by the range information. The range of the service area is a range specified by an absolute position expressed by latitude and longitude, for example. When there are a plurality of service areas, a plurality of area range information is input from the service control unit 102, and the area detection unit 138 can detect a service area including the position of the host vehicle. The service area detection information is input to the frequency setting means 106 because it is used to set the in-vehicle group frequency and the inter-vehicle group frequency.

[Hardware Configuration Example of Inter-Vehicle Communication Device 100]
Next, a hardware configuration example of the vehicle-to-vehicle communication device 100 according to the present embodiment will be briefly described with reference to FIG. FIG. 3 is an explanatory diagram illustrating a hardware configuration example of the inter-vehicle communication device 100 according to the present embodiment. The hardware configuration of the inter-vehicle communication devices 200 and 300 according to the second and third embodiments described later is the same as this.

  As shown in FIG. 3, the functions of the inter-vehicle communication device 100 include hardware such as a GPS receiver H12, a central processing unit (CPU) H14, a memory H16, a communication control unit H18, an RF front-end circuit H20, an antenna H22, and the like. Realized by resources. The central processing unit H14, the memory H16, and the communication control unit H18 are connected by a bus H24.

  The GPS receiver H12 is means for detecting the position of the host vehicle at each time. The GPS receiver H12 is connected to the central processing unit H14. The central processing unit H14 is an arithmetic processing chip. The memory H16 is a semiconductor memory such as a RAM (Random Access Memory) or a ROM (Read Only Memory), or a magnetic recording medium.

  The memory H16 stores, for example, area range information, own vehicle state information, vehicle number information, transmission / reception data, and the like. The communication control unit H18 is a control chip that controls the RF front end circuit H20 and the like. The RF front end circuit H20 is a signal processing circuit that executes signal processing such as frequency conversion and signal amplification of an RF signal. The antenna H22 is a transmission / reception antenna for an RF signal output from the RF front end circuit H20.

  Heretofore, a hardware configuration example of the inter-vehicle communication device 100 according to the present embodiment has been briefly described. The correspondence relationship between these hardware resources and the functional configuration is as described above. Of course, this hardware configuration is an example, and the present embodiment is not limited to this.

[Specific examples of service areas]
Here, a service area setting example will be briefly described with reference to FIGS. 4 and 5. FIG. 4 is a service area setting example (case (1)) for preventing a right turn accident at an intersection. FIG. 5 is a service area setting example (case (2)) for preventing encounter accidents at crossroads and preventing pedestrians from jumping off at T-shaped roads.

  In addition to this, examples of setting service areas to which the technology according to the present embodiment can be applied include frontal collision prevention, rear-end collision prevention, left turn-in accident prevention, or contact accident prevention when changing lanes. There are various application examples. Of course, the application range of the present embodiment is not limited to these examples. However, for convenience of explanation, only the case (1) and the case (2) will be described, and description of the other cases will be omitted.

(About Case (1))
First, referring to FIG. FIG. 4 shows an intersection, a plurality of vehicles C1, C2, C3, and the service area SA. Here, attention is paid to the vehicles C1, C2, and C3 located near the center of the intersection. The vehicle C1 is a straight traveling vehicle. Vehicles C2 and C3 are right turn vehicles. In such a situation, the right turn vehicle C2 may not be able to see whether the straight vehicle C1 is coming from behind the opposing right turn vehicle C3, and there is a possibility that an accident in which the straight vehicle C1 and the right turn vehicle C2 collide will occur. is there.

  In such a case, for example, the warning information that informs the existence of each other is notified to both the straight traveling vehicle C1 and the right turn vehicle C2, thereby increasing the probability that a right turn collision accident can be prevented. Then, the vehicle situation in the intersection is notified to the following vehicle of the straight traveling vehicle C1 or the right turn vehicle C2, so that the driver can recognize the situation and predict the accident. Such notification is realized by the inter-vehicle communication.

  However, it is not only such warnings and notifications that can be realized by the inter-vehicle communication. For example, it may be used for purposes such as exchanging control information between vehicles and controlling the vehicle so as not to collide or contact each other.

  Assuming the above situation, for example, as shown in FIG. 4, a service area SA that covers a large intersection is set. In particular, in the example of FIG. 4, in order to realize a collision accident prevention service between a right-turn vehicle (for example, the vehicle C2) approaching in the −X direction and a straight-ahead vehicle (for example, the vehicle C1) traveling in the X direction, It is set long along the road extending in the direction. Further, since a collision accident at the time of a right turn is mainly assumed, the service area SA is set so that the central portion of the intersection is largely covered.

  The length of the service area is set based on vehicle behavior, braking distance, and the like. At this time, the length of the service area takes into account the length of the right turn lane, the position where the driver of the right turn vehicle will turn the blinker, and the distance from when the driver of the right turn vehicle and the opposite straight vehicle driver steps on the brake until the vehicle stops. Must be set. Therefore, it is preferable that the length of the service area is determined based on the section in which the right-turn vehicle displays the intention to turn right and the idle travel distance and the braking distance of the right-turn vehicle and the opposite straight vehicle.

(About Case (2))
Reference is now made to FIG. On the right side of FIG. 5 (close to the −X direction), a crossroad, a building, a wall, a plurality of vehicles C1, C2, etc., and a plurality of service areas SA1, SA2 are described. Further, on the left side (close to the X direction) in FIG. 5, a T-shaped road, a vehicle C3, a pedestrian M1, and a plurality of service areas SA3 and SA4 are described.

  First, pay attention to the vehicles C1 and C2 located near the center of the crossroads. Vehicles C1 and C2 are straight-ahead vehicles that go straight in the X direction and the Y direction, respectively. Accordingly, the vehicles C1 and C2 are assumed to encounter accidents. In particular, there are walls and high buildings along the road in the vicinity of the crossroads, and the vehicle C2 that goes straight in the Y direction cannot be visually recognized from the vehicle C1 that goes straight in the X direction.

  Usually, such a crossroad is equipped with a mirror, and the driver relies on the map reflected on the mirror. However, there are cases where the mirror is hidden by trees, the sun is reflected, and the visibility is lowered, or the mirror is damaged in the first place. In such a case, if vehicle information such as the position and speed of each other can be recognized between the vehicles C1 and C2, it is possible to remarkably increase the probability that a collision accident at the time of encounter can be prevented.

  However, as shown in FIG. 5, since walls and buildings generally shield radio waves, if a straight communication method such as DSRC is used, communication between vehicles C1 and C2 cannot be performed, or a crossroad It is finally possible to communicate at the point where it is approaching. In this way, it is impossible to avoid a collision at the time of encounter. Therefore, when there is a shield, it is preferable to use a communication system that can bypass the shield by diffraction.

  Also, it is necessary to consider the frequency band utilization efficiency. Therefore, a selective usage form of a communication system that uses a communication system that can bypass the shield only by communication between the vehicle groups is preferable. For example, a method of using DSRC for intra-vehicle communication and UHF for inter-vehicle communication is conceivable. The DSRC has high straightness and is suitable for communication within a local range. On the other hand, since UHF has relatively little diffraction loss, communication that bypasses the shield is possible.

  In this way, when different communication methods are used for intra-vehicle group communication and inter-vehicle group communication, as shown in FIG. 5, service areas SA1, SA2 are provided for each road along the traveling direction of the vehicles C1, C2. Is set. By setting in this way, vehicle information can be transmitted by a communication method such as UHF that is relatively less affected by the shielding between the vehicle groups set for each service area.

  The length of the service area is set based on the braking distance of the vehicle. At this time, the length of the service area must be set in consideration of the distance from when the driver steps on the brake until the vehicle stops. Therefore, it is preferable that the length of the service area is determined based on the free running distance and the braking distance.

  By the way, the technique according to the inter-vehicle communication device 100 described above is not applied only to the vehicle. For example, the safety of the pedestrian M1 can be enhanced by applying to a portable device such as a mobile phone held by the pedestrian M1.

  For example, as described on the left side of FIG. 5, when the pedestrian M1 jumps out of a narrow alley, a contact accident with the vehicle C3 is likely to occur. In such a situation, it is often difficult for the pedestrian M1 to visually recognize from the vehicle C3. In addition, when the alley is narrow, the mirror may not be installed, or the child may suddenly jump out without looking at the mirror. In such a case, if the vehicle C3 is notified of information such as the position and traveling direction of the pedestrian M1, a contact accident can be prevented in advance. In consideration of such a situation, service areas (SA3, SA4) are also installed in the vicinity of a narrow alley where the pedestrian M1 walks.

  The situation where the service area is installed has been briefly described above. As described above, the technique of the present embodiment can be applied to various situations, and is used for ensuring the safety of a moving body such as a vehicle or a pedestrian. In the above description, a mode has been described in which different communication methods are used for inter-car group communication and intra-car group communication. Below, it demonstrates on the assumption of this system. Of course, the technology according to the present embodiment is not limited to this.

[Service Area Layout]
Next, a service area arrangement method according to the present embodiment will be described with reference to FIG. FIG. 6 is an explanatory diagram showing an example of a service area arrangement method and an inter-vehicle communication method according to the present embodiment.

  In this example, an accident prevention service at an intersection is assumed as a provided service. In FIG. 6, the service areas (SA1, SA2, SA3, SA4) in the X direction and the Y direction in different ranges are set around the four intersections. In each service area, there are six vehicles in total, three in each direction (X direction, Y direction). Of these vehicles, the master is represented as Cm and the slave as Cs. Further, the master Cm is indicated by hatching, and the slave Cs is indicated by white.

  Here, in order to realize the encounter collision prevention service, the vehicle group (for example, vehicle group (1)) traveling in the Y direction from the master Cm of the vehicle group (for example, vehicle group (2)) traveling in the X direction. Consider a case where communication between vehicle groups is executed by the master Cm. Further, in this example, it is assumed that the transmission / reception frequencies of the vehicle group communication are set to be different from each other between adjacent intersections. For example, as shown in FIG. 6, the frequency is set to CH # 1 at the intersection where the service areas SA1 and SA3 exist, and is set to CH # 2 at the intersection where the service areas SA2 and SA4 exist (CH #). 1 ≠ CH # 2).

  However, when the distance between adjacent intersections is short, radio waves having the same frequency may interfere. Therefore, in this example, service area identification information (hereinafter referred to as area ID) for identifying a service area is set to a different value. This setting makes it possible to identify service areas having different area IDs even if the frequencies are the same. For a service in which a service area is set for each intersection, such as an encounter accident prevention service, a method of identifying the service area based on the intersection information using the correspondence between the area ID and the intersection can be considered. In that case, for example, position information of an intersection (for example, an absolute position expressed by latitude and longitude) can be used as the area ID.

[Frame structure]
Next, the configuration of the beacon frame according to the present embodiment will be described with reference to FIG. FIG. 7 is an explanatory diagram illustrating a configuration example of a beacon frame according to the present embodiment.

  As shown in FIG. 7, the beacon frame includes a MAC header, a transmission source vehicle group ID, a transmission source vehicle ID, a service area ID, data (vehicle group information), and a CRC. The MAC header indicates the source MAC address. The transmission source vehicle group ID is identification information for specifying the transmission source vehicle group. The transmission source vehicle ID is identification information for specifying the transmission source vehicle. The service area ID is the area ID described above. The data is vehicle group information and the like. CRC is a Cyclic Redundancy Check (Cyclic Redundancy Check) code.

  This beacon frame is transmitted at a predetermined cycle by the master in the vehicle group. The beacon frame may include vehicle group management information such as the vehicle position of the host vehicle and the number of vehicles in the vehicle group. The beacon frame is received by the vehicle that has entered the service area. And the vehicle group which should enter based on this beacon frame is determined, and the state of the own vehicle in a vehicle group is determined.

[Flow of inter-vehicle communication method]
Next, the flow of the inter-vehicle communication method according to the present embodiment will be described with reference to FIGS. 8 and 9 are flowcharts showing the flow of the inter-vehicle communication method according to this embodiment.

  Please refer to FIG. When a series of processing is started by the vehicle, it is first determined whether or not the host vehicle has entered the service area (S102). If it is determined that the vehicle has entered, the process proceeds to step S104. On the other hand, if it is determined that the vehicle has not entered, the process of step S102 is repeated.

  In step S104, a transmission / reception frequency is set based on the service area where the host vehicle is present (S104). Next, it is determined whether there is received data (S106). If it is determined that there is received data, the process proceeds to step S108. On the other hand, if it is determined that there is no received data, the process proceeds to step S112 (FIG. 9).

  In step S108, the data selection means 152 determines whether or not the transmission source vehicle is in the same service area as the host vehicle (S108). If it is determined that they are in the same service area, the process proceeds to step S110. On the other hand, if it is determined that they do not exist in the same service area, the received data is discarded and the process proceeds to step S112 (FIG. 9).

  In step S110, received data is acquired (S110). Reference is now made to FIG. In step S112, it is determined whether there is transmission data (S112). If it is determined that there is transmission data, the process proceeds to step S114. On the other hand, if it is determined that there is no transmission data, the process proceeds to step S118.

  In step S114, information capable of identifying the service area where the host vehicle is present is added to the transmission data (S114). Next, the transmission data is transmitted (S116). Next, it is determined whether or not to leave the service area (S118). If it is determined to leave the service area, the process proceeds to step S120. On the other hand, if it is determined not to leave the service area, the process again proceeds to the process of step S106 (FIG. 8).

  In step S120, the set transmission / reception frequency is canceled (S120), and a series of processing ends. Note that the order of the reception processing in steps S106 to S110 and the transmission processing in steps S112 to S116 may be interchanged.

  The first embodiment of the present invention has been described above. In this way, information on multiple vehicles or multiple vehicle groups that exist in multiple service areas is multiplexed by frequency, and by multiplexing the frame configuration within the same frequency, the lower layer that performs communication control allows It is possible to determine whether the information is related to a necessary service, and high real-time performance is realized.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the present embodiment, a vehicle group is formed by a plurality of vehicles, a master is selected from the vehicles in the vehicle group, and information on vehicles belonging to the vehicle group is transferred between the vehicles belonging to other vehicle groups by the master. It is related with the communication method between vehicles for exchanging in. In particular, the configuration is characterized in that information of a plurality of service areas is multiplexed by frequency.

[Functional configuration of inter-vehicle communication device 200]
The functional configuration of the vehicle-to-vehicle communication device 200 according to this embodiment will be described with reference to FIG. FIG. 10 is an explanatory diagram showing a functional configuration of the vehicle-to-vehicle communication device 200 according to the present embodiment. The main structural difference from the vehicle-to-vehicle communication device 100 according to the first embodiment is that the data selection means 152 is not provided.

  As shown in FIG. 10, the inter-vehicle communication device 200 is mainly composed of a service control unit 202, a vehicle position detection unit 204, a frequency setting unit 206, an inter-vehicle communication unit 208, and a vehicle group control unit 230. The

(Service control means 202)
The service control unit 202 is a unit that generates notification information in order to provide a predetermined service. This notification information includes information such as the position and speed of the host vehicle, or information generated by the service control means 202 in order to provide a predetermined service. For example, the service control unit 202 obtains other vehicle information, and performs processing necessary for a predetermined service based on the other vehicle information to generate notification information. This notification information is transmitted to other vehicles by the inter-vehicle communication means 208.

  In addition, the service control unit 202 inputs information indicating the range of a service area in which a predetermined service is provided (hereinafter, area range information) to the area detection unit 238. Note that the function of the service control unit 202 is realized by using resources such as the central processing unit H14 and the memory H16 in a hardware configuration to be described later, for example. For example, the position / range of the service area may be stored in the memory H16 as absolute position information expressed by latitude and longitude. At this time, together with the service area information, the contents of the service provided in the area may be stored in association with the memory H16.

(Vehicle position detection means 204)
The vehicle position detection unit 204 detects the position of the host vehicle. The vehicle position detection unit 204 detects an absolute position expressed by latitude and longitude, for example. The information on the absolute position detected by the vehicle position detection unit 204 is input to the area detection unit 238 described later. The function of the vehicle position detection unit 204 is realized by using resources such as a GPS receiver H12 in a hardware configuration described later, for example.

(Frequency setting means 206)
The frequency setting means 206 sets a transmission / reception frequency used when information is transmitted / received in intra-vehicle group communication and inter-vehicle group communication. The information on the transmission / reception frequency set by the frequency setting unit 206 is input to the vehicle-to-vehicle communication unit 208 described later. The in-vehicle group frequency and the inter-vehicle group frequency are determined by the service area detected by the area detecting unit 138. Note that the function of the frequency setting unit 206 is realized by using resources such as a communication control unit H18, a central processing unit H14, and a memory H16 in a hardware configuration described later.

(Vehicle communication means 208)
The vehicle-to-vehicle communication unit 208 generates a frame by adding information necessary for access control to the notification information input from the data processing unit 232. This frame is modulated by a predetermined modulation method, modulated at the transmission frequency set by the frequency setting means 206, and periodically transmitted.

  Further, the inter-vehicle communication unit 208 receives the modulation signal at the reception frequency set by the frequency setting unit 206 and demodulates the frame from the modulation signal. Further, the inter-vehicle communication unit 208 removes information necessary for access control from the demodulated frame, and extracts notification information of other vehicles included in the frame. The notification information extracted by the vehicle-to-vehicle communication unit 208 is input to the data processing unit 232.

  Note that the function of the vehicle-to-vehicle communication unit 208 is realized by using resources such as the communication control unit H18 and the RF front-end circuit H20 in a hardware configuration described later.

(Vehicle group control means 230)
The vehicle group control means 230 includes data processing means 232, vehicle group formation means 234, and area detection means 238. The function of the vehicle group control means 230 is realized by using resources such as the central processing unit H14, the memory H16, and the communication control unit H18 among the hardware configurations described later.

(Data processing means 232)
The data processing unit 232 has a function of selecting a transmission destination vehicle to which the notification information generated by the service control unit 202 should be transmitted and a reception source of the notification information to be received. Notification information is input to the data processing unit 232 by the service control unit 202. Further, the data processing unit 232 receives information on a vehicle group to which the host vehicle belongs, information on vehicles included in the vehicle group, state information on the host vehicle, and the like by a vehicle group forming unit 234 described later.

  First, a case where notification information is transmitted will be described. Based on the type of service provided by the service control unit 202, information on the own vehicle / other vehicle, etc., the data processing unit 232 should send the notification information to a vehicle in the vehicle group, or outside the vehicle group Judge what should be the next vehicle. In particular, the determination by the data processing means 232 depends on the state information of the host vehicle. For example, when the host vehicle is the master selected in the vehicle group, depending on the type of the notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups are also set as the transmission destination of the notification information. Need to be included in the vehicle. Through such a determination, the transmission destination of the notification information is designated and input to the vehicle-to-vehicle communication means 208. The method for selecting a transmission destination will be described in detail later.

  Next, reception of notification information transmitted from another vehicle will be described. Based on the type of service provided by the service control unit 202, information on the own vehicle / other vehicle, etc., the data processing unit 232 should set the transmission source of the notification information to be received to a vehicle in the vehicle group, or Determine whether the vehicle should be outside the vehicle group. In particular, the determination by the data processing means 232 depends on the state information of the host vehicle.

  For example, if the host vehicle is the master selected in the vehicle group, depending on the type of notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups also receive notification information to be received. It needs to be included in the sender. After such determination, the transmission source of the notification information to be received is designated and input to the vehicle-to-vehicle communication means 208. A method for selecting a transmission destination of information to be received will be described in detail later.

(Car group forming means 234)
The vehicle group formation means 234 forms a vehicle group with the own vehicle, causes the own vehicle to enter the already formed vehicle group, or causes the own vehicle to leave the vehicle group. Further, the vehicle group forming means 234 sets the state of the host vehicle. There are basically three types of vehicle status: master, slave, and outside the vehicle group. Then, the state of the host vehicle set by the vehicle group forming unit 234 is input to the data processing unit 232. The vehicle group forming unit 234 manages entry and exit from the vehicle group, particularly when the host vehicle is a master.

(Area detection means 238)
The area detection means 238 is based on the position information of the host vehicle input from the vehicle position detection means 204 and information indicating the service area range input from the service control means 202 (hereinafter, area range information). It is detected whether or not the position of the host vehicle is included in the service area indicated by the range information. The range of the service area is a range specified by an absolute position expressed by latitude and longitude, for example. When there are a plurality of service areas, a plurality of area range information is input from the service control unit 202, and the area detection unit 238 can detect a service area including the position of the host vehicle. The service area detection information is input to the frequency setting means 206 because it is used to set the in-vehicle group frequency and the inter-vehicle group frequency.

[Service Area Layout]
Next, a service area arrangement method according to the present embodiment will be described with reference to FIG. FIG. 11 is an explanatory diagram illustrating an example of a service area arrangement method and an inter-vehicle communication method according to the present embodiment.

  In this example, an accident prevention service at an intersection is assumed as a provided service. In FIG. 11, different service areas (SA1, SA2, SA3, SA4) are set around four intersections. In each service area, there are six vehicles in total, three in each direction (X direction, Y direction).

  Here, in order to realize the encounter collision prevention service, the vehicle group (for example, vehicle group (1)) traveling in the Y direction from the master Cm of the vehicle group (for example, vehicle group (2)) traveling in the X direction. Consider a case where communication between vehicle groups is executed by the master Cm. Further, in this example, it is assumed that the transmission / reception frequencies of the vehicle group communication are set to be different from each other between adjacent intersections. For example, as shown in FIG. 11, the frequency is set to CH # 1 at the intersection where the service areas SA1 and SA3 exist, and is set to CH # 2 at the intersection where the service areas SA2 and SA4 exist (CH #). 1 ≠ CH # 2). The main difference from the first embodiment is that no area ID is set for each intersection. When the distance between the intersections where the same frequency is set is more than a predetermined distance, radio wave interference does not matter so much, so such a setting can be made.

[Flow of inter-vehicle communication method]
Next, the flow of the vehicle-to-vehicle communication method according to the present embodiment will be described with reference to FIGS. 12 and 13 are flowcharts showing the flow of the inter-vehicle communication method according to this embodiment.

  Please refer to FIG. When a series of processes is started by the vehicle, it is first determined whether or not the host vehicle has entered the service area (S202). If it is determined that the vehicle has entered, the process proceeds to step S204. On the other hand, if it is determined that the vehicle has not entered, the process of step S202 is repeated.

  In step S204, the transmission / reception frequency is set based on the service area where the host vehicle is present (S204). Next, it is determined whether there is received data (S206). If it is determined that there is received data, the process proceeds to step S210. On the other hand, if it is determined that there is no received data, the process proceeds to step S212 (FIG. 13).

  In step S210, received data is acquired (S210). Reference is now made to FIG. In step S212, it is determined whether there is transmission data (S212). If it is determined that there is transmission data, the process proceeds to step S216. On the other hand, if it is determined that there is no transmission data, the process proceeds to step S218.

  In step S216, transmission data is transmitted (S216). Next, it is determined whether or not to leave the service area (S218). If it is determined to leave the service area, the process proceeds to step S220. On the other hand, if it is determined not to leave the service area, the process again proceeds to the process of step S206 (FIG. 12).

  In step S220, the set transmission / reception frequency is canceled (S220), and a series of processing ends. Note that the order of the reception processing in steps S206 and S210 and the transmission processing in steps S212 and S216 may be interchanged.

  The second embodiment of the present invention has been described above. In this way, by multiplexing information on multiple vehicles or multiple vehicle groups existing in multiple service areas by frequency, it is determined whether or not the information is related to a service required for the host vehicle in a lower layer that performs communication control. Therefore, high real-time performance is realized.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the present embodiment, a vehicle group is formed by a plurality of vehicles, a master is selected from the vehicles in the vehicle group, and information on vehicles belonging to the vehicle group is transferred between the vehicles belonging to other vehicle groups by the master. It is related with the communication method between vehicles for exchanging in. In particular, there is a feature in a configuration in which information on a service area where a vehicle group is formed is added to vehicle information or vehicle group information and transmitted.

[Functional configuration of inter-vehicle communication apparatus 300]
A functional configuration of the vehicle-to-vehicle communication device 300 according to the present embodiment will be described with reference to FIG. FIG. 14 is an explanatory diagram illustrating a functional configuration of the vehicle-to-vehicle communication device 300 according to the present embodiment. The main structural difference from the vehicle-to-vehicle communication device 100 according to the first embodiment is that the frequency setting means 106 is not provided.

  As shown in FIG. 2, the inter-vehicle communication device 300 mainly includes a service control unit 302, a vehicle position detection unit 304, an inter-vehicle communication unit 308, and a vehicle group control unit 330.

(Service control means 302)
The service control unit 302 is a unit that generates notification information in order to provide a predetermined service. This notification information includes information such as the position and speed of the host vehicle, or information generated by the service control means 302 to provide a predetermined service. For example, the service control unit 302 obtains other vehicle information, and generates notification information by executing processing necessary for a predetermined service based on the other vehicle information. This notification information is transmitted to other vehicles by the inter-vehicle communication means 308.

  In addition, the service control unit 302 inputs information indicating the range of a service area in which a predetermined service is provided (hereinafter, area range information) to the area detection unit 338. The function of the service control unit 302 is realized by using resources such as the central processing unit H14 and the memory H16 in a hardware configuration described later, for example. For example, the position / range of the service area may be stored in the memory H16 as absolute position information expressed by latitude and longitude. At this time, together with the service area information, the contents of the service provided in the area may be stored in association with the memory H16.

(Vehicle position detection means 304)
The vehicle position detection unit 304 detects the position of the host vehicle. The vehicle position detection unit 304 detects an absolute position expressed by latitude and longitude, for example. Information on the absolute position detected by the vehicle position detection unit 304 is input to an area detection unit 338 described later. Note that the function of the vehicle position detection unit 304 is realized by using resources such as a GPS receiver H12 in a hardware configuration described later, for example.

(Vehicle communication means 308)
The inter-vehicle communication unit 308 generates a frame by adding information necessary for access control to the notification information input from the data selection unit 352. This frame is modulated at a predetermined frequency and periodically transmitted at a predetermined transmission frequency.

  Further, the inter-vehicle communication unit 308 receives a modulation signal at a predetermined reception frequency and demodulates a frame from the modulation signal. Furthermore, the inter-vehicle communication means 308 removes information necessary for access control from the demodulated frame, and extracts notification information of other vehicles included in the frame. The notification information extracted by the inter-vehicle communication unit 308 is input to the data selection unit 352. Note that the function of the inter-vehicle communication unit 308 is realized by using resources such as the communication control unit H18 and the RF front-end circuit H20 in the hardware configuration described later.

(Vehicle group control means 330)
The vehicle group control means 330 includes data processing means 332, data sorting means 352, vehicle group formation means 334, and area detection means 338. The function of the vehicle group control means 330 is realized by using resources such as the central processing unit H14, the memory H16, and the communication control unit H18 in the hardware configuration described later.

(Data processing means 332)
The data processing unit 332 has a function of selecting a transmission destination vehicle to which the notification information generated by the service control unit 302 should be transmitted and a reception source of the notification information to be received. Notification information is input to the data processing unit 332 by the service control unit 302. Further, the data processing unit 332 receives information on a vehicle group to which the host vehicle belongs, information on a vehicle included in the vehicle group, status information on the host vehicle, and the like by a vehicle group forming unit 334 described later.

  First, a case where notification information is transmitted will be described. Based on the type of service provided by the service control unit 302, information on the own vehicle / other vehicle, etc., the data processing unit 332 should send the notification information to a vehicle in the vehicle group or out of the vehicle group Judge what should be the next vehicle. In particular, the determination by the data processing means 332 depends on the state information of the host vehicle. For example, when the host vehicle is the master selected in the vehicle group, depending on the type of the notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups are also set as the transmission destination of the notification information. Need to be included in the vehicle. Through this determination, the transmission destination of the notification information is designated and input to the inter-vehicle communication unit 308 via the data selection unit 352. The method for selecting a transmission destination will be described in detail later.

  Next, reception of notification information transmitted from another vehicle will be described. Based on the type of service provided by the service control unit 302, information about the own vehicle / other vehicle, etc., the data processing unit 332 should set the transmission source of the notification information to be received to a vehicle in the vehicle group, or Determine whether the vehicle should be outside the vehicle group. In particular, the determination by the data processing means 332 depends on the state information of the host vehicle.

  For example, if the host vehicle is the master selected in the vehicle group, depending on the type of notification information, in addition to the vehicles in the vehicle group, vehicles belonging to other vehicle groups also receive notification information to be received. It needs to be included in the sender. After such determination, the transmission source of the notification information to be received is designated and input to the vehicle-to-vehicle communication unit 308 via the data selection unit 352. A method for selecting a transmission destination of information to be received will be described in detail later.

(Data selection means 352)
The data selection unit 352 acquires information (hereinafter referred to as area information) regarding the service area where the host vehicle exists from the area detection unit 338. Then, the data selection unit 352 adds the acquired area information to the notification information input via the data processing unit 332. The notification information to which the area information is added is input to the inter-vehicle communication unit 308.

  On the other hand, when the notification information from another vehicle received by the inter-vehicle communication unit 308 is input, the data selection unit 352 refers to the area information added to the notification information, and within the service area where the host vehicle is located. Only the notification information about the vehicle or the vehicle group is selected. The selected notification information is input to the data processing unit 332.

(Car group forming means 334)
The vehicle group formation means 334 forms a vehicle group with the own vehicle, causes the own vehicle to enter the already formed vehicle group, or causes the own vehicle to leave the vehicle group. Furthermore, the vehicle group forming means 334 sets the state of the host vehicle. There are basically three types of vehicle status: master, slave, and outside the vehicle group. Then, the state of the host vehicle set by the vehicle group forming unit 334 is input to the data processing unit 332. The vehicle group forming unit 334 manages entry and exit from the vehicle group, particularly when the host vehicle is a master.

(Area detection means 338)
The area detection means 338 is based on the position information of the host vehicle input from the vehicle position detection means 304 and information indicating the range of the service area input from the service control means 302 (hereinafter, area range information). It is detected whether or not the position of the host vehicle is included in the service area indicated by the range information. The range of the service area is a range specified by an absolute position expressed by latitude and longitude, for example. When there are a plurality of service areas, a plurality of area range information is input from the service control unit 302, and the area detection unit 338 can detect a service area including the position of the host vehicle.

[Service Area Layout]
Next, a service area arrangement method according to the present embodiment will be described with reference to FIG. FIG. 15 is an explanatory diagram illustrating an example of a service area arrangement method and an inter-vehicle communication method according to the present embodiment.

  In this example, an accident prevention service at an intersection is assumed as a provided service. In FIG. 15, different service areas (SA1, SA2, SA3, SA4) are set around four intersections. In each service area, there are six vehicles in total, three in each direction (X direction, Y direction).

  Here, in order to realize the encounter collision prevention service, the vehicle group (for example, vehicle group (1)) traveling in the Y direction from the master Cm of the vehicle group (for example, vehicle group (2)) traveling in the X direction. Consider a case where communication between vehicle groups is executed by the master Cm. In this example, service area identification information (hereinafter referred to as area ID) for identifying a service area is set to a different value. This setting makes it possible to identify service areas with different area IDs. For a service in which a service area is set for each intersection, such as an encounter accident prevention service, a method of identifying the service area based on the intersection information using the correspondence between the area ID and the intersection can be considered. In that case, for example, position information of an intersection (for example, an absolute position expressed by latitude and longitude) can be used as the area ID.

[Flow of inter-vehicle communication method]
Next, the flow of the vehicle-to-vehicle communication method according to the present embodiment will be described with reference to FIGS. 16 and 17. 16 and 17 are flowcharts showing the flow of the inter-vehicle communication method according to the present embodiment.

  Refer to FIG. When a series of processing is started by the vehicle, it is first determined whether or not the host vehicle has entered the service area (S302). If it is determined that the vehicle has entered, the process proceeds to step S306. On the other hand, if it is determined that the vehicle has not entered, the process of step S302 is repeated.

  In step S306, it is determined whether there is received data (S306). If it is determined that there is received data, the process proceeds to step S308. On the other hand, if it is determined that there is no received data, the process proceeds to step S312 (FIG. 17).

  In step S308, the data selection means 352 determines whether or not the transmission source vehicle is in the same service area as the host vehicle (S308). If it is determined that they exist in the same service area, the process proceeds to step S310. On the other hand, if it is determined that they do not exist in the same service area, the received data is discarded and the process proceeds to step S312 (FIG. 17).

  In step S310, received data is acquired (S310). Reference is now made to FIG. In step S312, it is determined whether there is transmission data (S312). If it is determined that there is transmission data, the process proceeds to step S314. On the other hand, if it is determined that there is no transmission data, the process proceeds to step S318.

  In step S314, information capable of identifying the service area where the host vehicle is present is added to the transmission data (S314). Next, the transmission data is transmitted (S316). Next, it is determined whether or not to leave the service area (S318). If it is determined to leave the service area, the series of processing ends. On the other hand, if it is determined not to leave the service area, the process proceeds again to the process of step S306 (FIG. 16).

  Note that the order of the reception processing in steps S306 to S310 and the transmission processing in steps S312 to S316 may be interchanged.

  The third embodiment of the present invention has been described above. In this way, by multiplexing information of multiple vehicles or multiple vehicle groups that exist in multiple service areas with a frame configuration, it is possible to determine whether or not the information is related to services required for the host vehicle in a lower layer that performs communication control Thus, high real-time performance is realized.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the first and second embodiments described above, an example in which different frequencies are alternately set for each intersection has been described. However, the present invention is not limited to this example, and three or more frequencies are used and are different between adjacent intersections. You may set as follows.

It is explanatory drawing which shows the structural example of a communication apparatus between vehicles. It is explanatory drawing which shows the structural example of the inter-vehicle communication apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the hardware structural example of the inter-vehicle communication apparatus which concerns on the same embodiment. It is explanatory drawing which shows an example of the service area which concerns on the embodiment. It is explanatory drawing which shows an example of the service area which concerns on the embodiment. It is explanatory drawing which shows an example of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows an example of the frame structure which concerns on the same embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the structural example of the vehicle-to-vehicle communication apparatus which concerns on other one Embodiment of this invention. It is explanatory drawing which shows an example of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the structural example of the vehicle-to-vehicle communication apparatus which concerns on other one Embodiment of this invention. It is explanatory drawing which shows an example of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment. It is explanatory drawing which shows the flow of the inter-vehicle communication method which concerns on the embodiment.

Explanation of symbols

100, 200, 300 Inter-vehicle communication device 102, 202, 302 Service control means 104, 204, 304 Vehicle position detection means 106, 206 Frequency setting means 108, 208, 308 Inter-vehicle communication means 130, 230, 330 Vehicle group control means 132, 232, 332 Data processing means 152, 352 Data selection means 134, 234, 334 Vehicle group formation means 138, 238, 338 Area detection means H12 GPS receiver H14 Central processing unit H16 Memory H18 Communication control unit H20 RF front end circuit H22 Antenna H24 Bus M1 Pedestrian C1, C2, C3 Vehicle Cm Master Cs Slave SA, SA1, SA2, SA3, SA4 Service area

Claims (10)

A vehicle-to-vehicle communication method using the vehicles belonging to a vehicle group formed by a plurality of vehicles,
A position detection step in which the position of the host vehicle is detected;
Based on the position of the host vehicle detected in the position detection step, an area detection step in which an area including the position of the host vehicle is detected from one or a plurality of predetermined areas;
An area information adding step in which, when information is transmitted by the host vehicle, information on the area detected in the area detecting step is added to the information;
A data selection step in which only information to which information of the area detected in the area detection step is added is selected when information is received by the host vehicle;
A vehicle-to-vehicle communication method comprising:   The method further comprises a multiplexing step in which, when a plurality of areas are detected in the area detecting step, information on vehicles or vehicle groups existing in the plurality of areas is multiplexed according to a frame configuration. The inter-vehicle communication method according to 1. The transmission / reception frequency used for transmission / reception of the information further includes a frequency setting step in which a frequency is set for each area detected in the area detection step,
In the multiplexing step, according to the frequency set in the frequency setting step, information of vehicles or vehicle groups existing in the plurality of areas is multiplexed by frequency or frame configuration. Item 3. The inter-vehicle communication method according to Item 2.   The inter-vehicle communication method according to any one of claims 1 to 3, wherein in the area information adding step, position information of an intersection is used as the area information. A vehicle-to-vehicle communication method using the vehicles belonging to a vehicle group formed by a plurality of vehicles,
A position detection step in which the position of the host vehicle is detected;
Based on the position of the host vehicle detected in the position detection step, an area detection step in which the area including the position of the host vehicle is detected from one or a plurality of predetermined areas;
A frequency setting step in which a transmission / reception frequency used for transmission / reception of information is set for each area detected in the area detection step;
When a plurality of the areas are detected in the area detecting step, multiplexing of information on vehicles or vehicle groups existing in the plurality of areas according to the frequency set in the frequency setting step is multiplexed. Step,
A vehicle-to-vehicle communication method comprising: A vehicle-to-vehicle communication device provided in each vehicle of a vehicle group formed of a plurality of vehicles,
Position detecting means for detecting the position of the host vehicle;
Based on the position of the host vehicle detected by the position detection unit, an area detection unit that detects an area including the position of the host vehicle from one or a plurality of predetermined areas;
Area information adding means for adding information on the area detected by the area detecting means to the information when the information is transmitted by the own vehicle;
Data selection means for selecting only the information to which the area information detected by the area detection means is added when the information is received by the own vehicle;
A vehicle-to-vehicle communication device comprising:   7. The apparatus according to claim 6, further comprising a multiplexing unit configured to multiplex information of vehicles or vehicle groups existing in the plurality of areas by a frame configuration when a plurality of areas are detected by the area detecting unit. Vehicle-to-vehicle communication device described in 1. A frequency setting means for setting a transmission / reception frequency used for transmission / reception of the information to a frequency for each area detected by the area detection means;
The multiplexing means multiplexes information of vehicles or vehicle groups existing in the plurality of areas by frequency or frame configuration according to the frequency set by the frequency setting means. 8. The inter-vehicle communication device according to 7.   The inter-vehicle communication device according to any one of claims 6 to 8, wherein the area information adding means uses intersection position information as the area information. A vehicle-to-vehicle communication device provided in each vehicle of a vehicle group formed of a plurality of vehicles,
Position detecting means for detecting the position of the host vehicle;
Based on the position of the host vehicle detected by the position detection unit, an area detection unit that detects the area including the position of the host vehicle from one or a plurality of predetermined areas;
A frequency setting means for setting a transmission / reception frequency used for transmission / reception of information to a frequency for each area detected by the area detection means;
Multiplexing that multiplexes information of vehicles or vehicle groups existing in the plurality of areas by frequency according to the frequency set by the frequency setting means when the area detection means detects a plurality of the areas. Means,
A vehicle-to-vehicle communication device comprising:

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