JP2008294740A - Roadside machine for vehicle communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roadside machine for a vehicle communication system capable of surely transmitting information to surrounding vehicles through a roadside machine. <P>SOLUTION: The roadside machine for a vehicle communication system which is used in a vehicle communication system for respectively making a plurality of roadside machines installed on a road and a vehicle traveling on the road communication nodes to perform radio communication between the nodes and can be provided as a roadside machine for a vehicle communication system by being provided with an information distribution area setting means for variably setting an information distribution area for segmenting one or a plurality of information distribution destination nodes to be an information destination by communication so as to make the extent of an area appropriate in accordance with contents of main information to be distributed during communication with the roadside machine being an information start point node, an information distribution route determining means for determining an information distribution route from the information start point node to each information distribution destination node within the information distribution areas, and an information distributing means for distributing the main information to be distributed together with the determined distribution route information into the information distribution areas by radio. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a roadside device for a vehicle communication system used in a vehicle communication system that uses a plurality of roadside devices installed on a road and vehicles traveling on the road as communication nodes, and performs wireless communication between the nodes. Is.

  Bypass traffic information sent from outside the vehicle, such as VICS (Vehicle Information and Communication System: registered trademark), from the roadside equipment on which the vehicle is installed along the road to avoid the traffic congestion section Search and avoid traffic jams. Conversely, information can be transmitted from the vehicle to the roadside machine, and the information can be transmitted to another vehicle via, for example, the VICS center.

  In addition, a technology for communicating vehicle information and traffic information (inter-vehicle communication) between vehicles has been developed. Furthermore, a collision avoidance system has been devised in which communication is performed via a third vehicle when a partner vehicle to be communicated is outside the inter-vehicle communication range (see Patent Document 1).

  Further, for example, a traffic signal control system and a traffic signal control device have been devised that can perform communication between mobile stations such as vehicles via communication between signal controllers without passing through a control center (Patent Literature). 2).

  Moreover, while communicating the information between roads between roadside communication apparatuses, between the roadside communication apparatus and in-vehicle apparatus, the information of roadside communication between the road vehicles including the common contents and separate contents A roadside communication device and a traffic signal communication system characterized by performing information communication have been devised (see Patent Document 3).

JP 2005-227978 A JP 2001-023080 A JP 2006-163621 A

  In the example of Patent Document 1, when there is no vehicle that relays communication, there is a problem that inter-vehicle communication cannot be performed.

  In the examples of Patent Literature 2 and Patent Literature 3, what kind of communication is performed in which range is not disclosed.

  Also, when transmitting and receiving surrounding vehicle information to avoid collisions on roads with poor visibility, such as mountain roads, where the other vehicles do not pass, conventionally, communication is possible until the other vehicle comes within the vehicle-to-vehicle communication range. It was not possible, and notification of collision avoidance could be delayed.

  With the above problem as a background, an object of the present invention is to provide a roadside unit for a vehicle communication system capable of reliably transmitting information to surrounding vehicles via a roadside unit.

Means for Solving the Problems and Effects of the Invention

  A roadside device for a vehicle communication system for solving the above-described problems is a vehicle communication system that performs wireless communication between a plurality of roadside devices installed on a road and vehicles traveling on the road as communication nodes. Information distribution area for cutting out one or a plurality of information distribution destination nodes to be information distribution destinations by communication at the time of communication using the roadside machine as an information origin node Information distribution area setting means for variably setting the area size according to the content of the main information to be distributed, and information from the information origin node to each information distribution destination node in the information distribution area An information distribution route determining means for determining a distribution route; an information distribution means for wirelessly distributing main information to be distributed together with the determined distribution route information in an information distribution area; Characterized in that it comprises.

  With the above configuration, the information (main information) to be distributed even if the vehicle that relays the communication does not exist around the host vehicle or the vehicle that relays other communication does not exist (vehicle) , Information distribution destination node). In addition, since the roadside machine that first receives information from the vehicle becomes an information start node, and the information distribution area is determined according to the content of the main information, there is also an advantage that the driver of the vehicle does not perform any operation. .

  In addition, the roadside unit for a vehicle communication system according to the present invention refers to the information distribution route information accompanying the distributed main information when the roadside device for the vehicle communication system serves as a relay node when distributing the main information within the information distribution area. A distribution destination node determination unit that determines a node to be a next distribution destination, and a relay transmission unit that relays and transmits main information to the distribution destination node in the form of taking over the information distribution route information. You can also.

  With the above configuration, the relay node can shorten the time for determining the next distribution destination node, and can quickly distribute main information.

  Moreover, the roadside machine of this invention can also be comprised so that it may become an information origin node, when main information is received from a vehicle, and when it receives main information from another roadside machine, it becomes a relay node.

  With the above configuration, it is possible to determine whether the node is an information origin node or a relay node by a simple method. In addition, it is possible to avoid redundant setting of the information distribution area in each node.

  The main information in the roadside unit for a vehicle communication system of the present invention of the present invention may be configured to include at least one of vehicle speed information, position information, and traffic obstacle information around the vehicle. it can.

  With the above configuration, if the main information includes vehicle speed information and position information, the driving status of other vehicles can be grasped. If the main information includes traffic obstacle information, the surrounding traffic conditions can be grasped. can do.

  In the roadside unit for a vehicle communication system of the present invention, an area group having different predetermined areas is prepared as an information distribution area, and the information distribution area setting means has a wide area corresponding to the content of the main information. The information distribution area may be selected from the area group and set.

  With the above configuration, an appropriate information distribution area corresponding to the main information can be set without performing calculation for setting the area each time, and the main information can be reliably distributed to vehicles to be distributed. Further, it is possible to avoid disabling unnecessary information by distributing unnecessary information and confusing the driver of the vehicle that has received unnecessary information.

  Further, the information distribution area setting means in the roadside unit for a vehicle communication system of the present invention is configured to set the information distribution area according to the content of the traffic obstacle information when the main information includes traffic obstacle information. You can also

  With the above-described configuration, it is possible to reliably distribute the traffic obstacle information to the vehicle to be distributed. Further, it is possible to avoid irrelevant traffic obstacle information from being distributed and hinder other communications, or to confuse the driver of the vehicle that has received irrelevant traffic obstacle information.

  Further, the traffic fault information in the roadside unit for vehicle communication system of the present invention of the present invention includes at least one of traffic accident information and traffic jam information, and the information distribution area setting means depends on the scale of the traffic accident and traffic jam. An information distribution area may be set.

  Traffic accident information and traffic jam information have different effects on surrounding traffic depending on their scale or content. With the above configuration, traffic accident information and traffic jam information can be reliably delivered to vehicles that should be delivered. Further, it is possible to avoid irrelevant information from being distributed by obstructing other communications or confusing the driver of the vehicle that has received irrelevant information.

  Further, the information distribution area setting means in the roadside device for vehicle communication system of the present invention specifies an information origin node from the received distribution route information when the main information does not include traffic fault information, and the information origin node In addition, a predetermined range can be set as the information distribution area.

  The main information that does not include traffic obstacle information is, for example, traveling information of other vehicles. With the above configuration, the main information can be reliably delivered (returned) to the information origin node. Furthermore, even if other vehicles do not exist in the vicinity of the information origin node, the information distribution area is widely set including the information origin node, so that the main information is surely distributed to the other vehicle as the transmission source. Can do.

  The roadside machine for a vehicle communication system of the present invention according to the present invention includes a roadside machine installation location storage means for storing the installation location of the roadside machine, and an information distribution destination node included in the information distribution area, the roadside machine installation location storage means. And a node search unit that searches from the stored contents, and the information distribution route determination unit can be configured to determine the information distribution route based on the search result.

  With the above configuration, it is not necessary to actually search for surrounding roadside devices, so that an information distribution route can be determined in a short time.

  The roadside machine installation location storage means in the roadside machine for vehicle communication system of the present invention stores road shape data around the roadside machine, and the information distribution area setting means stores road shape data around the roadside machine. The information delivery area can be set accordingly.

  With the above configuration, for example, even on roads with poor visibility such as mountain roads, where the other vehicles hardly pass, it is possible to expand the information distribution area to a point where the visibility is better, and to quickly send main information to other vehicles. Can be delivered.

  Further, the information distribution area setting means in the roadside unit for a vehicle communication system of the present invention according to the present invention is based on the received main information, the vehicle is traveling on a road section where it is difficult to pass another vehicle, or When it is determined that traveling is expected, a predetermined range centering on a road section and a connection point between the road section and another road that can pass may be set as the information distribution area. it can.

  With the above configuration, it is possible to know that there is a vehicle traveling on a road before entering a road where it is difficult to pass another vehicle.

  Further, the roadside device search means in the roadside device for a vehicle communication system of the present invention searches for all adjacent nodes from the information distribution source node, further searches for adjacent nodes from the node, and distributes the information distribution destination. An information distribution route may be searched by a breadth-first search for searching for a node.

  The breadth-first search is one of well-known search algorithms, and searches are performed in parallel for all routes, so the first route found is the shortest route. With the above configuration, the information distribution route can be searched in a short time. In addition, since the shortest information distribution route is searched, the information distribution time is also shortened.

  Further, the relay node and the information distribution destination node in the roadside device for a vehicle communication system of the present invention of the present invention are configured to distribute main information to the vehicle traveling around the relay node and the information distribution destination node. You can also

  With the above configuration, the main information can be distributed to all the vehicles traveling in the information distribution area.

  Hereinafter, a configuration example of the present invention will be described with reference to the drawings. First, the configuration of the vehicle communication system will be described with reference to FIG. The vehicle communication system includes an in-vehicle device (not shown) mounted on the vehicle 101 and a plurality of roadside devices (roadside devices for vehicle communication system) 250. For example, the roadside machine 250 is installed along the road at intervals of 50 m or at every intersection.

  The vehicle-mounted device (100) mounted on the vehicle 101 will be described with reference to FIG. In the example of FIG. 2, the vehicle-mounted device is configured as a part of the function of the vehicle navigation device. Of course, it is good also as a structure independent as an onboard equipment, and it is good also as a structure as a part of other onboard equipment.

  A vehicle navigation device (hereinafter abbreviated as a navigation device) 100 includes a position detector 1, a map data input device 6, an operation switch group 7, a remote control (hereinafter referred to as a remote control) sensor 11, a voice synthesis circuit for performing voice guidance, and the like. 24, speaker 15, memory 9, display 10, transmitter / receiver 13, hard disk device (HDD) 21, LAN (Local Area Network) I / F (interface) 26, control circuit 8 connected to these, remote control terminal 12, etc. It has.

  The position detector 1 detects the position of the vehicle 101 based on a known geomagnetic sensor 2, a gyroscope 3 that detects the rotational angular velocity of the vehicle 101, a distance sensor 4 that detects the travel distance of the vehicle 101, and a radio wave from a satellite. A GPS receiver 5 is provided. Since these sensors 2, 3, 4, and 5 have errors of different properties, they are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy, some of the above-described sensors may be used, and further, a steering rotation sensor or a wheel sensor of each rolling wheel, such as a vehicle speed sensor 23, may be used.

  As the operation switch group 7, for example, a known touch panel 22 integrated with the display 10 or a mechanical switch is used. In addition to the mechanical switch, a pointing device such as a mouse or a cursor may be used.

  It is also possible to input various instructions using the microphone 31 and the voice recognition unit 30. In this method, a voice signal input from the microphone 31 is processed by a voice recognition technique such as a well-known hidden Markov model in the voice recognition unit 30, and converted into an operation command corresponding to the result. Various instructions can be input through the operation switch group 7, the remote control terminal 12, the touch panel 22, and the microphone 31.

  The control circuit 8 is configured as a normal computer, and includes a well-known CPU 81, ROM 82, RAM 83, I / O 84 as an input / output circuit, A / D conversion unit 86, drawing unit 87, clock IC 88, image processing unit 89, and A bus line 85 for connecting these components is provided. The CPU 81 controls the navigation program 21p and data stored in the HDD 21. In addition, a program for performing a minimum necessary operation as the navigation device 100 may be stored in the ROM 82 in a case where the data read / write control from the CPU 81 to the HDD 21 becomes impossible.

  The A / D conversion unit 86 includes a well-known A / D (analog / digital) conversion circuit, and converts analog data input from the position detector 1 or the like to the control circuit 8 into digital data that can be calculated by the CPU 81, for example. It is.

  The drawing unit 87 generates display screen data to be displayed on the display unit 10 from map data 21m (described later) stored in the HDD 21 or the like, display data, and display color data.

  The clock IC 88 is also called a real-time clock IC, and sends or sets clock / calendar data in response to a request from the CPU 81. The CPU 81 acquires date / time information from the clock IC 88. Further, date and time information included in the GPS signal received by the GPS receiver 5 may be used. The date information may be generated based on a real-time counter included in the CPU 81. The acquired date / time information is used, for example, for travel history management.

  The image processing unit 89 includes an image processing circuit that analyzes an image photographed by a camera 32 (described later) by a known technique such as pattern recognition. In the image processing unit 89, for example, a general binarization process is performed on the video signal photographed by the camera 32 to convert it into digital multi-value image data for each pixel. Then, a desired image portion is extracted from the obtained multi-value image data using a general image processing method.

  In addition to the navigation program 21p, the HDD 21 stores so-called map matching data for improving the accuracy of position detection, and map data 21m, which is a map database including road data representing road connections. The map data 21m stores predetermined map image information for display and road network information including link information and node information. The link information is predetermined section information constituting each road, and includes position coordinates, distance, required time, width, number of lanes, speed limit, and the like in the link attributes. The node information is information defining an intersection (branch road) or the like, and is composed of position coordinates, the number of right / left turn lanes, a connecting road link, a distance cost, and the like. In addition, data indicating whether or not traffic is possible is set in the inter-link connection information.

  In the HDD 21, auxiliary information for route guidance, entertainment information, and other data can be written independently by the user and stored as user data 21u. Data and various information necessary for the operation of the navigation device 100 are also stored as the database 21d.

  The navigation program 21p, map data 21m, user data 21u, and database 21d can be added and updated from the storage medium 20 via the map data input device 6. The storage medium 20 is generally a CD-ROM or DVD based on the amount of data, but may be another medium such as a memory card. Moreover, you may use the structure which downloads data via an external network.

  The memory 9 is composed of a rewritable device such as an EEPROM (Electrically Erasable & Programmable Read Only Memory) or a flash memory, and stores information and data necessary for the operation of the navigation apparatus 100. Has been. The memory 9 holds the stored contents even when the navigation device 100 is turned off. Further, necessary information and data may be separately stored in the memory 9 and the HDD 21 according to the operation of the navigation device 100.

  The display 10 is composed of a known color liquid crystal display, and includes a dot matrix LCD (Liquid Crystal Display) and a driver circuit (not shown) for performing LCD display control. The driver circuit uses, for example, an active matrix driving method in which a transistor is attached to each pixel so that the target pixel can be reliably turned on and off, and a display command sent from the control circuit 8 (drawing unit 87) and Display is performed based on the display screen data. Further, an organic EL (ElectroLuminescence) display or a plasma display may be used as the display 10.

  For example, the transceiver 13 receives road traffic information from the VICS center 14 by an optical beacon or a radio beacon output from a transmitter (not shown) provided along the road, or an FM multiplex broadcast. Device. Moreover, it is good also as a structure which can be connected to external networks, such as the internet, using the transmitter / receiver 13. FIG.

  The speaker 15 is connected to a well-known voice synthesis circuit 24, and the digital voice data stored in the memory 9 or the HDD 21 is converted into analog voice by the voice synthesis circuit 24 in response to a command from the navigation program 21p. Note that speech synthesis methods include a recording / editing method in which speech waveforms are stored as they are or after being encoded and connected as necessary, and a text synthesis method in which corresponding speech is synthesized from character input information.

  Further, by communicating with the ETC on-vehicle device 17, fee information received by the ETC on-vehicle device 17 from the toll gate can be taken into the navigation device 100. Further, the ETC on-vehicle device 17 may be connected to an external network and communicate with the VICS center 14 or the like.

  The vehicle speed sensor 23 includes a rotation detection unit such as a known rotary encoder. For example, the vehicle speed sensor 23 is installed in the vicinity of the wheel mounting unit to detect the rotation of the wheel and send it to the control circuit 8 as a pulse signal. In the control circuit 8, the number of rotations of the wheel is converted into the speed of the vehicle 101 to calculate an expected arrival time from the current position of the vehicle 101 to a predetermined place, or an average vehicle speed for each travel section of the vehicle 101. To do.

  The LAN I / F 26 is an interface circuit for exchanging data with other in-vehicle devices and sensors via the in-vehicle LAN 27. Further, data may be taken from the vehicle speed sensor 23 or connected to the ETC on-vehicle device 17 via the LAN I / F 26.

  With this configuration, the navigation device 100 allows the user to operate the operation switch group 7, the touch panel 22, the remote control terminal 12, or from the microphone 31 when the navigation program 21 p is activated by the CPU 81 of the control circuit 8. When a destination is set from a menu (not shown) displayed on the display 10 by voice input, the current position of the vehicle 101 is obtained by the position detector 1, and using a known Dijkstra method, A process for obtaining an optimum guide route from the current position to the destination is performed. Then, the guidance route is displayed on the road map on the display 10 so as to guide the user to the appropriate route. In addition, at least one of the display 10 and the speaker 15 performs notification of a message according to an operation guidance or an operation state.

  The communication unit 25 is configured as a well-known wireless transceiver, and is used for communication with the roadside device 250.

  The camera 32 is composed of a known CCD video camera or the like, and the captured image data is sent to the control circuit 8 (image processing unit 89). The camera 32 is attached to, for example, the front center part of the ceiling or the dash panel in the vehicle compartment so that the front of the vehicle can be photographed. It is desirable that the photographing range is wider than at least the visual field range of the driver.

  The radar 34 is for measuring the distance between the vehicle 101 and the front object by applying a known Doppler effect by emitting electromagnetic waves or ultrasonic waves and receiving a reflected wave from the front object. The radar 34 is attached to a front bumper of the vehicle 101, for example.

  With the above configuration, the navigation device 100 can communicate with the roadside device 250, analyze the information received from the roadside device, determine the transmission source of the information, and create main information to be transmitted to the roadside device 250. Will be able to do.

  The configuration of the roadside machine 250 will be described with reference to FIG. The roadside machine 250 includes a control unit 251 that controls the operation of the entire roadside machine.

  The control unit 251 is configured as a normal computer. The CPU 252, ROM 253, RAM 254, clock IC 255, communication unit 256, I / O 257 that is an input / output circuit, memory 259, and a bus line 258 that connects these components. Is provided. The CPU 252 performs control using the control program 253p and data stored in the ROM 253. The control unit 251 corresponds to information distribution area setting means, information distribution route determination means, distribution destination node determination means, and node search means of the present invention.

  The clock IC 255 has the same configuration as the clock IC 88 in FIG. Further, the date information may be generated based on a known real-time counter included in the CPU 252.

  The communication unit 256 is configured as a well-known wireless transceiver, and is used to communicate with the navigation device 100 (on-vehicle device) and other roadside devices. The communication unit 256 corresponds to the information distribution unit and the relay transmission unit of the present invention.

  The memory 259 is configured by a known non-volatile memory such as a flash memory, a roadside machine ID for specifying a roadside machine, a roadside machine 250, and a predetermined range centering on the roadside machine such as a radius of 5 km, for example. The position data of the other roadside machine installed in the road and the road shape data in a predetermined range centering on the roadside machine are stored. The road shape data includes, for example, width, gradient, curvature, and the like. Further, the road shape data may have the same contents as the road map data 21m of FIG. The memory 259 corresponds to the roadside machine installation location storage means of the present invention.

  With the above configuration, the roadside device 250 transmits and relays the information, and creates distribution information and distribution route information based on the received information or the transmission source of the information.

The main information transmission process in the navigation device 100 will be described with reference to FIG. This process is included in the navigation program 21p and is repeatedly executed together with other processes of the navigation program 21p. First, main information for transmission is generated (S000). The main information includes at least one of the following items.
The current position of the vehicle 101 detected by the position detector 1
The vehicle speed of the vehicle 101 detected by the vehicle speed sensor 23.
・ Traffic obstacle information (traffic accident information, traffic jam information).

  As for the traffic obstacle information, the image data taken by the camera 32 is analyzed by the image processing unit 89, and compared with the accident image or the traffic jam image stored in advance in the database 21d, the degree of similarity exceeds a predetermined threshold value. In case, it is judged as a traffic accident or a traffic jam. At this time, the current position of the vehicle 101 is also transmitted.

  The size of the traffic jam can also be determined by the vehicle speed. For example, when traveling at 20 km / h, it is determined that the traffic congestion scale is small, and when starting and stopping are repeated, the traffic congestion scale is large. Further, when the interval (that is, the inter-vehicle distance) between the objects (that is, other vehicles) detected by the radar 34 is less than a predetermined value, it may be determined that there is a traffic jam.

  In addition, a traffic obstacle information creation screen (FIG. 5) is displayed from a menu (not shown) displayed on the display 10 by the user operating the operation switch group 7, the touch panel 22, the remote control terminal 12, or by voice input from the microphone 31. (Not shown) may be displayed, and a method of creating accident or traffic jam information may be used. If the traffic information received from the VICS center 14 includes traffic congestion information around the host vehicle, the traffic fault information may be created based on the information.

  Next, it is determined whether or not the main information transmitted this time is a reply to the information received via the roadside device. This may be determined by determining whether the main information received by the communication unit 25 is received from the roadside device 250. Since what is received from the roadside machine 250 includes the roadside machine ID of the roadside machine that transmitted the main information, it is determined whether or not it is received from the roadside machine 250 based on the presence or absence of the roadside machine ID. it can. Thereby, a reply destination can be determined.

  Also, a unique in-vehicle device ID is set in advance in the in-vehicle device, that is, the navigation device 100, the in-vehicle device ID is transmitted to the road side device 250 together with main information, and the road side device 250 receives the road side device ID and the in-vehicle device in the received data. The determination may be made depending on which ID is included.

  When it is not a reply with respect to the information received via the roadside machine (S001: No), it is judged using the communication unit 25 whether the vehicle which can communicate between vehicles exists in the circumference | surroundings of the vehicle 101. FIG. When there is no vehicle capable of inter-vehicle communication around the vehicle 101, that is, when radio waves from other vehicles cannot be received by the communication unit 25 within a predetermined time (S002: No), the transmission mode is set to the broad transmission mode. (S003). Then, main information is sent to the roadside machine 250, and the roadside machine 250 performs communication processing via the roadside machine that performs communication via the roadside machine (S004, described later).

  On the other hand, when there is a vehicle capable of inter-vehicle communication around the vehicle 101 (S002: Yes), well-known inter-vehicle communication is performed (S005).

  If the reply is for information received via the roadside machine (S001: Yes), the transmission mode is set to the individual transmission mode (S006). And the communication process via a roadside machine which communicates via the roadside machine 250 is performed (S004, mentioned later).

  The main information includes transmission mode information in addition to the above. Transmission mode information is used when communication is performed via the roadside device 250. In the case of inter-vehicle communication communication, blank data or meaningless numerical values are set in the transmission mode information.

  With reference to FIG. 5, the roadside unit communication process corresponding to step S004 of FIG. 4 and executed by the control program 253p of the roadside unit 250 will be described. First, the transmission source of the information received by the communication unit 256 is specified. For example, when information from another roadside machine is received, the distribution route information is included in addition to the main information, and therefore the information source can be specified by the presence or absence of the distribution route information.

  When the distribution route information is not included and the transmission source of the main information is specified as the vehicle (101) (S011: No), the distribution range and the information distribution area are determined according to the content of the main information (S012).

FIG. 6 shows an example of the distribution range and information distribution area.
・ Special: This is to notify the surroundings of the existence of the vehicle, and is basically in the range necessary for collision avoidance support set for each roadside machine. As shown in FIG. 8, on a general road, an information distribution area is set within a certain range from an intersection where the host vehicle is approaching in order to avoid a collision. In addition, in the case of narrow roads such as mountain roads, as shown in Fig. 9, considering passing support, the information distribution area is not limited to a certain range, but is connected to the connection point between the narrow and wide roads and to the next intersection. Set a wide range.
Reply destination + small: A reply is made to a specific vehicle (that is, a roadside machine), and a distribution-side roadside machine that is a reply target and a circle with a radius of 200 m centering on the roadside machine are used as the information delivery area.
・ Medium: For distributing information that has relatively little effect on surrounding traffic, such as notification of emergency vehicles approaching or traveling, small traffic jams, or small accidents. A circle with a radius of 2 km at the center is set as the information distribution area.
・ Large: For distributing information that has a relatively large impact on surrounding traffic, such as large-scale traffic jams or large-scale accidents. For example, distribute a circle with a radius of 5 km centered on the roadside machine that is the distribution source. Let it be an area.

  Returning to FIG. 5, based on the determined information distribution area, distribution route information generation processing for generating distribution route information is executed (S013, described later). Then, the main information and the generated distribution route information are transmitted to the roadside machine corresponding to the next distribution source using the wireless unit 256 (S014). Finally, the received main information is transmitted to a designated partner such as a vehicle around the roadside machine (S015). Information on the designated vehicle is included in the delivery route information. In this case, the transmission target may not be specified and the transmission may be made to an unspecified target.

  On the other hand, when the distribution route information is included and the transmission source of the main information is specified as the roadside machine (250) (S011: Yes), the end point of the information distribution route is based on the distribution route information received together with the main information. If it is not the end point of the information distribution route (S016: No), the processes of steps S014 and S015 described above are sequentially executed.

  Further, when the terminal device itself is the end point of the information distribution route (S016: Yes), the process of step S015 described above is executed.

  FIG. 7 shows an example of data that the vehicle 101 (navigation device 100) transmits to the roadside device 250. The above distribution range type, transmission mode, and main information are included. In the case of inter-vehicle communication, only position information and vehicle speed information in the main information are transmitted, and the distribution range type and transmission mode may not be transmitted. Moreover, you may include the above-mentioned vehicle equipment ID.

  The delivery route information generation process corresponding to step S013 of FIG. 5 will be described using FIG. In this process, each roadside device is regarded as a node, and an information distribution route is searched using a known breadth-first search algorithm. In the case of normal broad transmission, a breadth-first search algorithm is simply executed. In the case of individual transmission, first, a route to a roadside device as a reply destination is created by breadth-first search, and a small range of broad distribution is performed from there.

  The algorithm used for searching the information distribution route is not limited to the breadth-first search algorithm, and other search algorithms such as a depth-first search algorithm may be used.

  First, the current node (distribution source roadside machine) is added to the queue as a root node (S021). The queue is a FIFO (First-In, First-Out) method, and an area is secured in the RAM 254. Next, it is determined whether or not the queue is empty. If the queue is not empty (S022: Yes), the head node stored in the queue is taken out (S023).

  Next, the transmission mode is specified from the main information received from the vehicle first (S024). When the transmission mode is the individual transmission mode, the process proceeds to step S026, and it is determined whether or not the node extracted from the queue is a reply destination node. If the node taken out from the queue is a reply destination node (S026: Yes), no other delivery route is required, so the route other than the route from the root node to the current delivery destination (reply destination node) is deleted and delivered from the root node. One information distribution route to the destination node is determined (S028).

  Thereafter, the notification range type is set to a small value, the reply destination node is set as the root node, the transmission mode is changed to the broad transmission mode, and a broad delivery route from the reply destination node is searched (S029 → S021).

  On the other hand, when the node taken out from the queue is not the reply destination node (S026: No), the delivery route is set with all the unvisited nodes among the nodes that can communicate with the taken out node (that is, adjacent) as the next transmission destination. After being additionally registered in the information, all the nodes are added to the queue (S027). Then, the process returns to step S022, and the processes after step S022 are repeated until there is no queue.

  If the transmission mode is the broad transmission mode, the process advances to step S025 to determine whether or not the node extracted from the queue is included in the notification range, that is, the information distribution area. When the node taken out from the queue is included in the information distribution area (S025: Yes), the process of step S027 described above is executed. Then, the process returns to step S022, and the processes after step S022 are repeated until there is no queue.

  On the other hand, when the node taken out from the queue is not included in the information distribution area (S025: No), the process returns to step S022, and the processes after step S022 are repeated until there is no queue.

  Further, when the queue is empty (S022: No), this process is terminated.

Next, specific examples in the above-described processes will be described with reference to FIG.
(Specific example 1: FIGS. 11 to 13)
As shown in FIG. 11, a roadside machine (●) was arranged, and a large-scale traffic accident occurred in front of the host vehicle (101) traveling near the point A. However, there is no other vehicle that can communicate by inter-vehicle communication around the host vehicle. At this time, the flow of information distribution for transmitting traffic accident information to other vehicles in the vicinity and suppressing confusion such as traffic congestion will be described.

The main information transmission process of FIG. 4 is performed as follows.
Step S001: Since the information is transmitted by itself, the process proceeds to No.
Step S002: Since there is no other vehicle within the vehicle-to-vehicle communication range, the process proceeds to No.
Step S003: Set to the broad transmission mode.
Step S004: Communication is performed via a roadside device.

The communication process via the roadside device in FIG. 5 is performed as follows (roadside device A).
-Step S011: Since it is transmission from onboard equipment, it progresses to No.
Step S012: Since the accident is a large-scale traffic accident, the notification range (information distribution area) is set large.
Step S013: An information distribution route is determined (distribution route information generation process).

The delivery route information generation process of FIG. 10 is performed as follows.
Step S021: Node (roadside machine) A is added to the queue as a root node.
Step S023: Since node A is in the queue, it is removed from the queue.
Step S024: Since the current mode is the broad transmission mode, the process proceeds to step S025.
Step S025: Since node A is within the notification range, the process proceeds to step S027.
Step S027: Nodes B, C, D, and E can communicate with node A this time. At this time, since the nodes B, C, D, and E are not visited, four of AB, AC, AD, and AE are registered as the next information distribution routes. Thereafter, these nodes B, C, D, and E are added to the queue, and the process returns to step S022.
Similarly, the processing of steps S023 to S027 is performed for node B. At this time, nodes A and F can communicate from the node B, but since the node A has already been visited, only the node F is added, and the information distribution paths are A-B-F, A-C, A-D. , A-E, and the queue states are C, D, E, F.
By repeating the same operation, an information distribution route as shown in FIG. 12 is created as a result.

  In FIG. 12, the information distribution area is shown as a circular region R1 surrounded by a broken line with node A as the center. The information distribution route is indicated by a dotted line connecting the nodes. The information distribution direction is indicated by Δ.

The main information transmission process of FIG. 5 after the distribution route information generation process is performed as follows.
Step S014: Main information and distribution route transmitted from the vehicle to the roadside machine (B, C, D, E) which is a child of the current roadside machine in the information distribution route tree generated by the distribution route information generation process Send information and.
Step S015: Furthermore, the main information is also transmitted to the vehicle existing in the vicinity of the current roadside machine (A) in order to expand the main information. Since this time it is a broad distribution for unspecified majority, there are no restrictions on the transmission target.

In the roadside devices (B, C, D, E, etc.) serving as relay nodes, the communication processing via the roadside device in FIG. 5 is performed as follows.
-Step S011: Since it is a transmission from a roadside machine, it progresses to Yes.
Step S016: If the current roadside machine is not the end of the information distribution route, the process proceeds to step S014, where relay and main information are transmitted. On the other hand, if the current roadside machine is the end of the information distribution route, the process proceeds to step S015, and the main information is also transmitted to the vehicle existing in the vicinity of the current roadside machine.

  Through the above processing, the main information is finally expanded as shown in FIG. The transmission range of the main information is indicated by a region R2 indicated by oblique lines centering on each roadside machine. Thereby, even when there is no other vehicle in the vehicle-to-vehicle communication range, information can be quickly deployed to surrounding vehicles. This makes it possible to avoid traffic jams in advance and contribute to improving fuel efficiency.

(Specific example 2: FIGS. 14 to 16)
It is assumed that the roadside machine (●) is arranged as shown in FIG. 14 and the vehicle status of the oncoming vehicle 102 is received through the roadside machine in a narrow alley where it is difficult to pass vehicles. Therefore, in order to perform the passing assistance, the main information is transmitted to the roadside machine A with the reply destination roadside machine as the node N in order to transmit the information of the own vehicle (101) to the vehicle 102.

The main information transmission process of FIG. 4 is performed as follows.
Step S001: Since the communication is made via the roadside machine, the process proceeds to Yes.
Step S006: Set to individual transmission mode.
Step S004: Communication is performed via a roadside device.

The communication process via the roadside device in FIG. 5 is performed as follows (roadside device A).
-Step S011: Since it is transmission from in-vehicle equipment, it progresses to No.
Step S012: Since it is reply information, the notification range (information distribution area) is set to reply destination + small.
Step S013: An information distribution route is determined (distribution route information generation process).

The delivery route information generation process of FIG. 10 is performed as follows.
Step S021: Node A is added to the queue as a root node.
Step S023: Since node A is in the queue, it is removed from the queue.
Step S024: Since it is the current individual transmission mode, the process proceeds to Step S026.
Step S026: Since the retrieved queue is not the reply destination node N, the process proceeds to No.
Step S027: Nodes B, C, and D are nodes that can communicate with the node A. At this time, since the nodes B, C, and D have not been visited, three of AB, AC, and AD are registered as the next information distribution routes. Thereafter, these nodes B, C, and D are added to the queue, and the process returns to step S022.
Similarly, the processing of steps S023 to S027 is performed for node B. At this time, nodes A and E can communicate from the node B, but since the node A has already been visited, only the node E is added, and the information distribution paths are A-B-E, A-C, A-D. Thus, the queue states are C, D, and E.
By repeating the same operation, the information distribution route is A-B-E-H-K-K-M-N-O, A-B-E-H-K-K-M-N-P, A-C-F. ..., A-D-G ... are obtained. Here, when N is extracted from the queue, the determination in step S026 is No, so the process proceeds to step S028.
Step S028: Since the route to the reply destination has been determined as A-B-E-H-K-M-N, other routes are deleted.
Step S029: Change to the broad transmission mode and return to step S021. Thereafter, a broad transmission distribution route having a small notification range with the node N as a root node is created, and as a result, an information distribution route (A-B-E-H-K-M-N-P-Q as shown in FIG. , A-B-E-H-K-M-N..., A-B-E-H-K-M-N--R...

  In FIG. 15, the route indicated by the broken line from the node A from which the own vehicle 101 has transmitted the main information to the node N that is the distribution source of the main information of the vehicle 102 is surrounded by the broken line R3 centering on the node N. A circular area is shown as an information distribution area. The information distribution direction is indicated by Δ.

The main information transmission process of FIG. 5 after the distribution route information generation process is performed as follows.
Step S014: The main information and distribution route information transmitted from the vehicle are transmitted to the roadside machine (B) that is a child of the current roadside machine in the information distribution route tree generated by the distribution route information generation process.
Step S015: Furthermore, the main information is also transmitted to the vehicle existing in the vicinity of the current roadside machine (A) in order to expand the main information. Since the vehicle 102 is targeted this time, the transmission destination may be designated as the vehicle 102 and the main information may be transmitted. However, there is a possibility that a vehicle other than the vehicle 102 is traveling in the information distribution area. The main information may be transmitted without specifying the destination.

  When the transmission destination is designated, the above-described vehicle-mounted device ID may be included in the main information transmitted from the distribution source roadside device.

The communication processing via the roadside device in FIG. 5 in the roadside device serving as the relay node is performed as follows.
-Step S011: Since it is a transmission from a roadside machine, it progresses to Yes.
Step S016: If the current roadside machine is not the end of the information distribution route, the process proceeds to step S014, where relay and main information are transmitted. On the other hand, if the current roadside machine is the end of the information distribution route, the process proceeds to step S015, where the transmission destination is designated as the vehicle 102 and the main information is transmitted. At this time as well, there is a possibility that a vehicle other than the vehicle 102 is traveling in the information distribution area. Therefore, the main information may be transmitted without specifying the transmission destination.

  With the above processing, the information is finally expanded as shown in FIG. The transmission range of the main information is indicated by a region R4 indicated by diagonal lines centering on each roadside machine. Thus, information can be reliably deployed to the other party even in inter-vehicle communication via a roadside machine that lacks some real-time performance.

  Although the embodiments of the present invention have been described above, these are merely examples, and the present invention is not limited to these embodiments, and the knowledge of those skilled in the art can be used without departing from the spirit of the claims. Various modifications based on this are possible.

The figure which shows the structure of a vehicle communication system. The figure which shows the structure of the navigation apparatus for vehicles. The figure which shows the structure of a roadside machine. The flowchart explaining main information transmission processing. The flowchart explaining the communication process via a roadside machine. The figure which shows an example of a delivery range and an information delivery area. The figure which shows an example of the data which a vehicle transmits to a roadside machine. The figure which shows the example of a setting of the information delivery area in a general road. The figure which shows the example of a setting of the information delivery area in a narrow road. The flowchart explaining a delivery route information generation process. The figure which shows the specific example of the information delivery when a large-scale traffic accident occurs (specific example 1). The figure which shows the information delivery area and delivery route in FIG. 11 (specific example 1). The figure which shows the transmission range of the main information in FIG. 12 (specific example 1). The figure which shows the specific example of the information delivery in the case of passing through a narrow alley (specific example 2). The figure which shows the information delivery area and delivery route in FIG. 14 (specific example 2). The figure which shows the transmission range of the main information in FIG. 15 (specific example 2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Position detector 7 Operation switch group 8 Control circuit 21 Hard disk drive (HDD)
21d database 21m map data 22 touch panel 25 communication unit 100 vehicle navigation device 101 vehicle 250 roadside machine 251 control unit (information distribution area setting means, information distribution route determination means, distribution destination node determination means, node search means)
256 communication unit (information distribution means, relay transmission means)
259 memory (roadside machine installation location storage means)

Claims (13)

A roadside device for a vehicle communication system used in a vehicle communication system that performs wireless communication between a plurality of roadside devices installed on a road and vehicles traveling on the road as communication nodes, respectively,
At the time of communication using the roadside machine as an information origin node, an information distribution area for extracting one or a plurality of information distribution destination nodes to be information distribution destinations by the communication is determined according to the contents of main information to be distributed. Information distribution area setting means for variably setting so as to optimize the area;
Information distribution route determining means for determining an information distribution route from the information origin node to each information distribution destination node in the information distribution area;
Information distribution means for wirelessly distributing the main information to be distributed together with the determined distribution route information in the information distribution area;
A roadside device for a vehicle communication system, comprising: When it becomes a relay node when the main information is distributed in the information distribution area, a node serving as a next distribution destination is determined by referring to the information distribution route information accompanying the main information to be distributed. A delivery destination node determining means for determining;
The roadside unit for a vehicle communication system according to claim 1, further comprising: a relay transmission unit that relays and transmits the main information toward the distribution destination node in a form that takes over the information distribution route information.   The said roadside machine becomes the said information origin node when the said main information is received from the said vehicle, and becomes the said relay node when the said main information is received from another roadside machine. Roadside equipment for vehicle communication systems.   4. The vehicle communication system according to claim 1, wherein the main information includes at least one of vehicle speed information, position information, and traffic obstacle information around the vehicle. 5. Roadside machine. As the information distribution area, a group of areas having different predetermined areas are prepared,
The vehicle communication according to any one of claims 1 to 4, wherein the information distribution area setting unit selects and sets an information distribution area having a size corresponding to the content of the main information from the area group. Roadside machine for the system.   The roadside unit for a vehicle communication system according to claim 5, wherein, when the main information includes traffic fault information, the information distribution area setting means sets the information distribution area according to the content of the traffic fault information. The traffic obstacle information includes at least one of traffic accident information and traffic jam information,
The roadside unit for a vehicle communication system according to claim 6, wherein the information distribution area setting means sets the information distribution area according to a scale of the traffic accident and the traffic jam.   When the main information does not include traffic fault information, the information distribution area setting means identifies the information origin node from the received distribution route information, and sets a predetermined range from the information origin node to the information distribution area The roadside machine for a vehicle communication system according to any one of claims 4 to 7, which is set as follows. Roadside machine installation location storage means for storing the installation location of the roadside machine;
Node search means for searching the information delivery destination node included in the information delivery area from the stored contents of the roadside machine installation location storage means,
The roadside unit for a vehicle communication system according to any one of claims 1 to 8, wherein the information distribution route determination unit determines the information distribution route based on a search result. The roadside machine installation location storage means stores road shape data around the roadside machine,
The roadside unit for a vehicle communication system according to claim 9, wherein the information distribution area setting unit sets the information distribution area according to road shape data around the roadside unit.   The information distribution area setting means, based on the received main information, when it is determined that the vehicle is traveling on a road section where it is difficult to pass with other vehicles, or traveling is predicted, The roadside unit for a vehicle communication system according to claim 10, wherein a predetermined range centering on a road section and a connection point between the road section and another road that can pass is set as the information distribution area.   The roadside device search means searches for all adjacent nodes from the information distribution source node, further searches for adjacent nodes from the node, and searches the information distribution route by a breadth-first search for searching for the information distribution destination node. The roadside machine for a vehicle communication system according to any one of claims 9 to 11, which is searched.   The relay node and the information distribution destination node distribute the main information to the vehicle traveling around the relay node and the information distribution destination node. Road vehicle for vehicle communication systems.

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