JP5292911B2 - COMMUNICATION SYSTEM, RADIO COMMUNICATION METHOD, AND COMMUNICATION DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system capable of eliminating the lack of radio resources for road-to-vehicle or vehicle-to-vehicle communication, thereby performing the stable wireless communication of information required for supporting safety driving and smoothing traffic. <P>SOLUTION: The communication system comprises a road-side communication apparatus installed along a road and an onboard communication apparatuses mounted on a plurality of vehicles traveling on the road and is configured to allocate a plurality of radio resources for performing multiplex wireless communication respectively between the onboard communication apparatuses and between the road-side communication apparatus and the onboard communication apparatuses, wherein the road-side communication apparatus comprises: a priority table including a plurality of tables indicating different transmission priorities in accordance with traffic volume; an acquisition means for acquiring information indicating the traffic volume of a vehicle; and a selection means for selecting a table corresponding to the traffic volume on the basis of the traffic volume indicated by the information acquired by the acquisition means and the priority table and selecting information to be contained in each of radio resources on the basis of the selected table. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a communication system, a wireless communication method, and a communication apparatus that realize an intelligent transport system (ITS).

  The Intelligent Transport System is a system built for the purpose of safe driving support and improved transportation efficiency. It runs on multiple roadside communication devices, roadside sensors, and other infrastructure installed separately along the road. It is comprised from the vehicle-mounted communication apparatus mounted in each of the some vehicle to perform (for example, patent documents 1, 2).

The roadside communication device performs safe driving support information and smooth communication by performing multiplex wireless communication, for example, wireless communication using a time division multiple access method, with an in-vehicle communication device mounted on a vehicle (hereinafter referred to as road-to-vehicle communication). Information for realizing traffic, for example, information on the control result of the signal lamp is provided to the vehicle in real time. Safe driving support information includes, for example, information for preventing a driver's recognition error, information for assisting blind spots, obstacles on the road detected by road sensors, travel positions and speeds of surrounding vehicles collected from in-vehicle communication devices Etc. The in-vehicle communication device that has received the information supports safe driving by giving a warning to the driver when it is determined that there is a danger from the vehicle position, the inter-vehicle distance, the traveling speed, and the like. In addition, information such as the speed of the vehicle, the traveling position, and the traveling direction is transmitted and received between the in-vehicle communication devices (hereinafter referred to as “vehicle-to-vehicle”), and safe driving is supported using the transmitted and received information.
The roadside communication device mainly transmits and receives information for realizing smooth traffic between roadside communication devices (hereinafter referred to as roadside) and between roadside cars, and using the information, the color of the signal lamp Switching control is performed.

In the time division multiple access method, a fixed communication time (frame) in the same frequency band is time-divided into a plurality of time slots, and the road side communication device and the in-vehicle communication device are assigned to each time slot between roads, between roads, and between vehicles. This method is used alternately, and enables simultaneous communication using the band effectively (see FIG. 5).
Japanese Patent No. 3463102 JP 2000-124852 A

  However, in a conventional communication system that employs multiple wireless communication, for example, a time division multiple access method sharing the same frequency band, when the traffic volume of the vehicle increases, there is a shortage of time slots for road-to-vehicle or vehicle-to-vehicle communication. There is a risk that it will not be possible to provide full safe driving support and smooth traffic.

  The present invention has been made in view of such circumstances, and it is possible to solve a shortage of radio resources for road-to-vehicle or vehicle-to-vehicle communication, and to perform stable wireless communication of information required for safe driving support and smooth traffic. An object of the present invention is to provide a communication system, a wireless communication method, and a communication apparatus.

A communication system according to a first aspect of the present invention includes a roadside communication device installed along a road, and an in-vehicle communication device mounted on each of a plurality of vehicles traveling on the road. A communication system that allocates a plurality of radio resources for performing multiplex radio communication between devices and between the roadside communication device and the in-vehicle communication device, wherein the roadside communication device transmits to the in-vehicle communication device storage means for storing priority data indicating should do multiple types of information each transmission priority of, based on the previous SL priority data to which the storage means stores, selects information to be included in the radio resource selection means when, and means for acquiring a communication state information indicating the quality of the communication state of the vehicle communication device, said selecting means, if the communication state indicated by the acquired communication state information is bad, the free Increase the amount of information with high transmission priority to be included in the resource, decrease the amount of information with low transmission priority, and include in each radio resource when the communication state indicated by the acquired communication state information is good It is characterized in that the amount of information with high transmission priority is decreased and the amount of information with low transmission priority is increased .
In a communication system according to a second aspect of the present invention, the roadside communication device includes acquisition means for acquiring information indicating at least one of a traffic volume of a vehicle and communication traffic of the in-vehicle communication device, and the selection means includes the acquisition means. The information to be included in each radio resource is selected based on at least one of the traffic volume and communication traffic indicated by the acquired information and the priority data.

In the communication system according to a third aspect of the invention, the priority data includes a plurality of priority data elements indicating different transmission priorities according to the traffic volume or communication traffic, and the selection means is acquired by the acquisition means A priority data element corresponding to the traffic volume or communication traffic is selected, and information included in each radio resource is selected based on the selected priority data element.

Very communication system according to the fourth invention, the pre-Symbol roadside communication device, comprising the emergency information obtaining means for obtaining emergency information about the emergency situation, selection means, acquired in the emergency information obtaining means situation information, and based on the priority data, characterized that you are so as to select the information to be included in each radio resource.

In the communication system according to a fifth aspect , the priority data includes a plurality of priority data elements indicating different transmission priorities according to emergency information, and the selecting means responds to the acquired emergency information. A priority data element is selected, and information to be included in each radio resource is selected based on the selected priority data element.

The communication system according to a sixth aspect of the invention is characterized in that the selection means includes more information with high transmission priority in each radio resource than information with low transmission priority.

According to a seventh aspect of the present invention, there is provided a wireless communication method comprising: a roadside communication device installed along a road; and an in-vehicle communication device mounted on each of a plurality of vehicles traveling on the road. A wireless communication method for allocating a plurality of radio resources for performing multiplex radio communication between communication devices and between the roadside communication device and the in-vehicle communication device, each of a plurality of types of information to be transmitted to the in-vehicle communication device prepared priority data indicating a transmission priority, and acquires the communication state information indicating the quality of the communication state of the vehicle communication device, based on the previous SL priority data, the communication state indicated by the acquired communication state information If it is bad, increase the amount of information with high transmission priority to be included in each radio resource, decrease the amount of information with low transmission priority, and if the communication state indicated by the acquired communication state information is good, Reduce the amount of transmission priority is higher information should be included in a radio resource, so to increase the amount of transmit low priority information, and selects the information to be included in each radio resource.

A communication device according to an eighth invention is a communication device that allocates a plurality of radio resources for performing multiplex radio communication between a plurality of mobile communication devices and between the mobile communication devices to the mobile communication device, storage means for storing priority data indicating a plurality of types of information each transmission priority that should be transmitted to the mobile communication device, based on the previous SL priority data to which the storage means stores the information to be included in each radio resource Selecting means, and means for acquiring communication state information indicating the quality of the communication state of the in-vehicle communication device, the selecting means, each of the communication state indicated by the acquired communication state information is defective, When the amount of information with high transmission priority to be included in the radio resource is increased, the amount of information with low transmission priority is decreased, and the communication state indicated by the acquired communication state information is good, each radio resource Reduce the amount of higher transmission priority to be included information, characterized that you have to increase the amount of transmit low priority information.

In the first, second, seventh and eighth inventions, the roadside communication device stores priority data indicating the transmission priority of each of a plurality of types of information to be transmitted to other roadside communication devices and in-vehicle communication devices. Memorized storage means is provided. By referring to the priority data, it is possible to determine which type of information should be preferentially transmitted when radio resources are insufficient.
The acquisition unit of the roadside communication device acquires information indicating the traffic volume of the vehicle or the communication traffic of the in-vehicle communication device. Since the traffic volume and the communication traffic correspond to the shortage amount of the radio resource, the lack of the radio resource can be determined by acquiring the information. The selection means of the roadside communication device selects information to be included in each radio resource based on at least one of the traffic volume and communication traffic indicated by the information acquired by the acquisition means and the priority data. In other words, the roadside communication device does not transmit all the information, but selects and transmits information having a high transmission priority to be transmitted according to the traffic volume or communication traffic, thereby increasing the traffic volume between Indirectly resolve the shortage of radio resources for inter-vehicle communication. In the eighth invention, the mobile communication device is a superordinate concept of the in-vehicle communication device, and the fixed communication device and the communication device are superordinate concepts of the roadside communication device. In particular, the communication device according to the seventh invention functions as a roadside communication device by being installed on a road. Further, the present invention includes not only a configuration for selecting information to be transmitted according to traffic volume or communication traffic, but also a configuration for selecting information to be transmitted according to both traffic volume and communication traffic. Furthermore, for multiplex wireless communication, not only TDM (Time Division Multiplexing), but also FDM (Frequency Division Multiplexing), OFDMA (Orthogonal Frequency Division Multiplexing Access), CDM (Code Division Multiplexing), other multiple wireless communication systems, each system Is also included. The radio resource means a time slot in TDM, a subcarrier in FDM, OFDMA, etc., and a code in CDM. Furthermore, the in-vehicle communication device may be a mobile terminal such as a mobile phone.
In the first, second, seventh and eighth inventions, the roadside communication device acquires communication state information indicating whether the communication state of the in-vehicle communication device is good or bad. Then, when the communication state is poor, the roadside communication device increases the amount of information with high transmission priority to be included in each radio resource, and decreases the amount of information with low transmission priority. For example, when the communication state shown in FIG. 11 is changed from the good state to the bad communication state shown in FIG. Reduce the amount of information with low transmission priority. Then, only the information with the highest transmission priority is assigned three times over two radio resources, thereby increasing the amount of information with high transmission priority. In short, the amount of information having a high transmission priority is relatively increased, that is, the total number of continuous transmissions is increased for transmission. When the number of continuous transmissions increases, the opportunity to receive information with high transmission priority by the in-vehicle communication device increases, and the probability of reception failure can be reduced as a whole. Therefore, it becomes possible to transmit information having a high transmission priority to the in-vehicle communication device more reliably.
When the communication state is good, the roadside communication apparatus decreases the amount of information with high transmission priority to be included in each radio resource, and increases the amount of information with low transmission priority. Therefore, when the communication state is good, information with low transmission priority can be transmitted without being thinned out.

In the third invention, the priority data includes a plurality of priority data elements indicating different transmission priorities depending on traffic volume or communication traffic. In general, the transmission priority of information to be transmitted varies depending on traffic conditions, and a plurality of priority data elements included in the priority data are for dealing with such variation in transmission priority. is there. For example, when the traffic volume or communication traffic is low, the vehicle is in a quiet or near-saturated state and the vehicle is moving at high speed. In many cases, since the vehicle is in a near-saturated state or a super-saturated state, the transmission priority of information relating to traffic smoothness should be set high. And a selection means selects the priority data element according to traffic volume or communication traffic, and selects the information included in each radio | wireless resource. Therefore, the roadside communication apparatus can cope with fluctuations in the importance of information according to traffic conditions, and can selectively transmit information required in each state.

In the fourth shot bright, roadside communication apparatus includes a storage means for storing priority data indicating a plurality of types of information each transmission priority that should be transmitted to another roadside communication apparatus and vehicle-mounted communication device . By referring to the priority data, it is possible to determine which type of information should be preferentially transmitted in an emergency.
The emergency information acquisition means of the roadside communication device acquires emergency information regarding an emergency. By referring to the acquired emergency information, it is possible to determine whether there is an emergency. In an emergency situation, it is required to transmit specific information with certainty, and radio resources may be insufficient to transmit the information with certainty. Therefore, the selection unit of the roadside communication device selects information to be included in each radio resource based on the emergency information acquired by the emergency information acquisition unit and the priority data. In other words, the roadside communication device does not transmit all the information, but selects and transmits information having a high transmission priority to be transmitted according to the contents of the emergency information. Indirectly resolve the shortage of radio resources for inter-vehicle communication.

In the fifth invention, the priority data includes a plurality of priority data elements indicating different transmission priorities according to emergency information. Generally, the transmission priority of information to be transmitted varies depending on whether it is an emergency such as an earthquake, a fire or other disaster, or terrorism. Multiple priority data elements included in the priority data Is to cope with such a change in transmission priority.
For example, the emergency information indicates either a normal state or an emergency. In this case, one priority data element indicates the priority of each information at normal time, and the other priority data elements indicate the priority in emergency. More specifically, as shown in FIG. 4, the table 14 a corresponding to one priority data element has a sensor detection result of priority number 1 and priority level 2 when the emergency information indicates a normal state. No. roadside device state information, restriction information of priority No. 3 and the like. The table 14c corresponding to other priority data elements includes emergency status information with priority 1 when emergency information indicates an emergency, regulatory information with priority 2 and hospitals with priority 3 Contains information. When the emergency information indicates an emergency, the transmission priority of information related to the emergency is set to be high.
The emergency information indicates a plurality of types of emergency situations, for example, types of earthquakes, fires, terrorism, and the like and normal states. In this case, different transmission priorities are set according to each emergency and normal state. For example, the first priority data element indicates the priority of each information in a normal state. The second priority data element indicates the priority of each information when an earthquake occurs. The third priority data element indicates the priority of each information when a fire occurs. The priority data element indicates the priority of each information when terrorism occurs.
The roadside communication device acquires emergency information regarding an emergency, and the selection unit selects a priority data element corresponding to the acquired emergency information, and selects information to be included in each radio resource. Therefore, the roadside communication device can cope with fluctuations in the importance of information due to an emergency, and can selectively transmit information required in each state.

In the sixth invention, the selection means includes more information with a high transmission priority in the radio resource than information with a low transmission priority. For example, when a plurality of radio resources for multiplex radio communication are prepared, information with a high transmission priority, for example, information with the first to fifth highest transmission priorities is assigned to all radio resources, and the transmission priority is the highest six. By assigning the first and lower information in order to the empty portions of each radio resource, information with a high transmission priority can be included in the radio resource more.
Therefore, it becomes possible to transmit information having a high transmission priority to the in-vehicle communication device more reliably.

  According to the present invention, by selecting information to be included in each radio resource according to the transmission priority according to the traffic situation, the importance of the information that varies according to the traffic situation is grasped, and the importance according to the traffic situation is determined. Information can be preferentially transmitted. Therefore, a shortage of radio resources for road-to-vehicle or vehicle-to-vehicle communication in the communication system can be indirectly solved, and stable wireless communication of information required for safe driving support and smooth traffic can be performed.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
FIG. 1 is an explanatory diagram conceptually showing a communication system according to an embodiment of the present invention. A communication system that implements the wireless communication method according to the present embodiment includes two roadside communication devices 1 and 1 (hereinafter referred to as roadside communication device 1) installed on the roadside of road R, for example, intersections B1 and B2, and roads (Hereinafter referred to as “vehicle C”) mounted on a plurality of vehicles C, C,... (Hereinafter referred to as “vehicle C”) and R (hereinafter referred to as “vehicle-mounted communication device 3”). The in-vehicle communication device 3 supports safe driving by transmitting and receiving various information related to safe driving support, traffic smoothing, and emergency situations between roads, road vehicles, and vehicles by wireless communication using a time division multiple access method.

  In the time division multiple access method, a fixed communication time (frame) in the same frequency band is time-divided into a plurality of time slots (radio resources), and a plurality of roadside communication devices 1 and in-vehicle communication devices 3 alternate each time slot. By using it, simultaneous communication is possible. According to the time division multiple access method, the same frequency band, for example, the UHF band, can be shared between roads, roads and vehicles, and vehicles can be used effectively. Note that the frequency band for wireless communication is not limited to UHF, and other bands may be used.

  FIG. 2 is an explanatory diagram conceptually illustrating an example of a data format of information transmitted and received by the roadside communication device 1 and the in-vehicle communication device 3 in a time slot. Information transmitted and received by the roadside communication device 1 and the in-vehicle communication device 3 is composed of a header part, a data part, and a footer part. In the header portion, for example, identification information indicating that the data is transmitted from the roadside communication device 1, an intersection number, and the like are stored. The data part stores safe driving support, information on traffic smoothing, information on emergency situations, etc. transmitted to the in-vehicle communication device 3 or the roadside communication device 1.

  FIG. 3 is a block diagram showing the configuration of the communication system. The roadside communication device 1 includes a communication unit 11 that performs wireless communication of a time division multiple access method between the surrounding roadside communication device 1 and the vehicle-mounted communication device 3 using the antenna 10, and the vehicle-mounted communication device 3 or the roadside communication device 1. Control unit 12 for performing various communication controls such as selection of information to be transmitted to roads, allocation management of time slots relating to road-to-road, road-to-vehicle and vehicle-to-vehicle wireless communication, and provision of safe driving support information, and various communication control processes And a storage unit (storage means) 13 in which necessary information is stored.

  A roadside communication device 1 installed at an intersection B1 on the left side in FIG. 1 centrally manages wireless communication between road vehicles and between vehicles in a cross-shaped wireless communication area A1 indicated by a solid line. In the wireless communication area A1, by assigning different time slots prepared in advance so as not to compete with each in-vehicle communication device 3, the road-side communication device 1 and the in-vehicle communication device 3 can communicate with each other between roads and vehicles and between vehicles. Communicate. Similarly, the roadside communication device 1 installed at the intersection B2 on the right side in FIG. 1 centrally manages wireless communication between road vehicles and between vehicles in the wireless communication area A2.

  The road-to-vehicle communication method includes an individual communication method and a broadcast communication method. In this embodiment, a broadcast communication method that can effectively use a radio wave band is adopted. The individual communication method is a method in which a communication connection is established independently for each in-vehicle communication device 3, and since wireless communication is performed interactively between road vehicles, it is excellent in confidentiality and communication stability. On the other hand, the broadcast communication method is a communication method in which the roadside communication device 1 transmits the same information to all the vehicles C, and the vehicle-mounted communication device 3 selects the same information. Therefore, it is possible to effectively use the radio wave band.

  The control unit 12 is, for example, a microcomputer including a CPU and an interface, and a clock (not shown) for performing wireless communication by a time division multiple access method is connected to the control unit 12. The control unit 12 is connected to the optical beacon 4, the image sensor 5, the signal lamp 6, the computer of the traffic control center 2, and the like shown in FIG. Sending and receiving. For convenience of drawing, a communication line connecting the roadside communication device 1 to the optical beacon 4, the image sensor 5, the signal lamp 6, and the traffic control center 2 is not shown.

  The memory | storage part 13 memorize | stores the various information transmitted from the optical beacon 4, the image sensor 5, and the traffic control center 2 grade | etc.,. Further, the storage unit 13 stores a priority table (priority data) 14 for improving the reception probability of important information by the in-vehicle communication device 3 or the roadside communication device 1.

  The optical beacon 4 includes a beacon head attached to a horizontal portion of a support frame installed on a road R near the outer edge of the wireless communication areas A1 and A2, and a beacon control device attached to a vertical portion of the support frame. Yes. The beacon head includes a projector / receiver for performing optical communication using near infrared rays between the in-vehicle communication devices 3. The installation position of the optical beacon 4 shown in FIG. 1 is an example, and the optical beacon 4 may be installed at another point.

  The optical beacon 4 projects a near-infrared optical signal toward the road R on which the vehicle C travels, and performs bi-directional optical communication with the vehicle C passing through the light projecting / receiving area. For example, when the in-vehicle communication device 3 that has entered the light emitting / receiving area transmits a time slot allocation request to the optical beacon 4 to perform wireless communication in a non-competitive manner, the optical beacon 4 The allocation request is received, and the received allocation request is transmitted to the roadside communication device 1. The roadside communication device 1 receives the assignment request transmitted from the optical beacon 4 and assigns the time slot corresponding to the traffic condition and the communication state of the in-vehicle communication device 3 to the in-vehicle communication device 3.

  The image sensor 5 is installed at the intersections B1 and B2 in a posture capable of capturing an image of the vehicle C traveling on the road R. The image sensor 5 includes a lens, an image sensor, an image processing circuit, a transmission unit, and the like. The image processing circuit calculates the traffic volume of the vehicle C traveling on the road R based on the image obtained by imaging with the imaging device, and the transmission unit displays the traffic volume information indicating the calculated traffic volume on the roadside communication device. 1 to send.

The traffic volume information may be transmitted from the traffic control center 2 to the roadside communication device 1. That is, the computer of the traffic control center 2 collects image data from the image sensor 5, calculates traffic based on the collected image data, and transmits traffic information indicating the calculated traffic to the roadside communication device 1. You may comprise as follows.
Moreover, although the example which measures a traffic volume based on the image obtained by imaging was demonstrated, the vehicle which drive | works the road R by the vehicle detector which detects the vehicle C using an ultrasonic wave, a far infrared ray, etc., an optical beacon, etc. You may comprise so that the traffic volume of C may be measured.

  The traffic control center 2 is a vehicle detector (not shown) installed on the road side of the road R, sensor information transmitted from a road surface condition detector, emergency situation information regarding emergency situations such as earthquakes, fires, terrorism, etc. Information is collected and accumulated. Based on the accumulated sensor information, the traffic control center 2 grasps the road R where the vehicle sensor is installed and the surrounding traffic conditions, and provides various information for safe driving support and traffic smoothing. It transmits to the roadside communication apparatus 1. For example, the traffic control center 2 provides the road-side communication device 1 with the color timing of the signal lamp 6, the traffic information of the intersections B1 and B2, and the like. Further, the traffic control center 2 transmits emergency state information indicating whether or not there is an emergency to the roadside communication device 1 based on the collected emergency situation information.

The information transmitted from the roadside communication device 1 that has collected various information to the in-vehicle communication device 3 includes the display lamp color of the signal lamp 6 and the duration of the display lamp color as information for supporting safe driving of the vehicle C. Information on road schedules, regulation information on traffic regulations on road R, road shape information on road R shapes such as the number of lanes and gradients, road surface information on road surface conditions on road R, administration such as traffic safety campaigns by administrative agencies Notification information and the like are included (see FIG. 4).
Further, the roadside communication device 1 communicates with the surrounding roadside communication devices 1 on the signal control result information regarding the control result of the signal lamp 6, the vehicle C flowing from the upstream intersections B1, B2 to the downstream intersections B1, B2. Traffic information related to the predicted traffic volume and traffic information around the roadside communication device 1 are shared by transmitting and receiving 5 minutes traffic information related to the traffic volume of the vehicle C traveling on the road R for 5 minutes.

FIG. 4 is an explanatory diagram conceptually showing the priority table 14. The priority table 14 includes a plurality of tables (priority data elements) 14a, 14b, and 14c that differ depending on whether the traffic volume is large or an emergency occurs.
The table 14a used when the traffic volume is small includes signal information, regulation information, road shape information, road surface information, administrative notice information, etc. transmitted from the roadside communication device 1 to the in-vehicle communication device 3 or other roadside communication devices 1. The type of information is associated with the transmission priority of each information item when the traffic volume is small, that is, the importance. Since the vehicle C is moving at a relatively high speed when the traffic volume is small, the transmission priority of information items related to safety is set high, and the transmission priority of other information items is set low. The smaller the numerical value shown in the transmission priority column, the higher the transmission priority.

  The table 14b used when the traffic volume is high associates signal information, regulation information, and the like with the transmission priority of each information item when the traffic volume is high. When there is a lot of traffic, in order to alleviate the traffic congestion and improve the environment and economy, the transmission priority of information items related to smooth traffic is set high, and the transmission priority of other information items is set low.

  The table 14c used in the case of an emergency is a table in which signal information, regulation information, and the like are associated with the transmission priority of each information item in an emergency. In the event of an emergency, in order to promote rescue and evacuation, and to maintain security, the transmission priority of information items related to emergency is set high and the transmission priority of other information items is set low.

By using the priority table 14 as will be described later, it becomes possible to transmit information corresponding to changes in the transmission priority of various types of information in accordance with traffic volume and emergency situations. That is, it is possible to improve the reception probability of important information by the in-vehicle communication device 3 by determining the content of the transmission information so that the number of continuous transmissions of information having a high transmission priority is optimized.
The transmission priority may be determined by weighting on the basis of traffic conditions or other communication means such as the optical beacon 4 or an information transmission request obtained from a mobile phone. For example, when the in-vehicle communication device 3 transmits an information transmission request for requesting transmission of restaurant information from the projector / receiver 34, the control unit 12 of the roadside communication device 1 transmits the information transmission request via the optical beacon 4. And the transmission priority of the restaurant information may be increased according to the received information transmission request.
In addition, each information may be independent information, but some or all of them may overlap.
Furthermore, when a plurality of information is transmitted, if there is a partially overlapping information part, only one overlapping information part may be transmitted and the other information part may be omitted.

Next, the configuration of the in-vehicle communication device 3 will be described. As shown in FIG. 3, the in-vehicle communication device 3 stores a communication unit 31 connected to the antenna 30, a control unit 32 that performs control related to communication, and information necessary for various processes such as communication processing and safe driving support processing. And a light projector / receiver 34 that performs optical communication with the optical beacon 4.
The control unit 32 of the in-vehicle communication device 3 has a function of self-diagnosis the communication state between road vehicles, particularly the reception state, and whether or not the information from the road side communication device 1 has been received or only a part of the information. Is configured to transmit communication status information indicating that it has been received. The communication status information can be included in, for example, a header portion of various information communicated between vehicles, and the roadside communication device 1 can acquire the communication status information by monitoring information communicated between vehicles. it can.
Note that the contents of the communication state information are examples. You may comprise so that the communication status information containing the time which received the information from the roadside communication apparatus 1 last time and a security code may be transmitted. Since the roadside communication device 1 knows the transmission time of information, the reception state of the in-vehicle communication device 3 can be grasped by referring to the communication state information transmitted by the in-vehicle communication device 3.

  In addition, when the in-vehicle communication device 3 enters the wireless communication areas A1 and A2, the on-vehicle communication device 3 requests time slot assignment via the light projector / receiver 34 and the optical beacon 4, and assigns the time slot transmitted from the roadside communication device 1. A result is received, and non-competing wireless communication is performed based on the received result. Outside the wireless communication areas A1 and A2, competitive wireless communication is performed with other in-vehicle communication devices 3.

  Next, a method for selecting transmission information and managing time slots by the roadside communication apparatus 1 will be described.

FIG. 5 is a flowchart illustrating a processing procedure of the control unit 12 related to the wireless communication of the roadside communication device 1.
First, the control unit 12 determines whether or not the timing unit has counted a predetermined information collection period, for example, 100 msec (step S11). When it determines with having measured the predetermined period (step S11: YES), the control part 12 acquires traffic volume information, emergency information, communication status information, and other various information (step S12).

  When the process of step S12 is completed, or when it is determined in step S11 that the predetermined information collection cycle has not been timed (step S11: NO), the control unit 12 receives a time slot allocation request from the in-vehicle communication device 3. It is determined whether or not there is (step S13).

  When it is determined that there is a time slot allocation request (step S13: YES), the control unit 12 calls a subroutine related to time slot allocation change and changes the time slot allocation (step S14).

FIG. 6 is an explanatory diagram conceptually showing an example of an assigned time slot, and FIG. 7 is a flowchart showing a processing procedure of a subroutine relating to the change of the assignment of the time slot.
In FIG. 6, the arrows indicate the time axis, and the rectangular cells arranged in the vertical direction indicate time slots. The roadside communication device 1 is a time slot for road-to-vehicle communication, a time slot for road-to-road communication, and a vehicle for vehicle-to-vehicle communication in order to perform time-division multiple access wireless communication between roads and vehicles, between roads and between vehicles. A time slot is assigned to each roadside communication device 1 and in-vehicle communication device 3. And the roadside communication apparatus 1 always grasps | ascertains the traffic volume of the vehicle C and the communication state of the vehicle-mounted communication apparatus 3 in order to perform stable wireless communication, and assigns time slots according to the traffic volume and the communication state. Make a change.
Specifically, the control unit 12 determines whether or not the time slot is insufficient, for example, whether or not the traffic volume is equal to or greater than a predetermined traffic volume and the traffic volume has increased (step S31). When it is determined that the time slots are insufficient (step S31: YES), the control unit 12 decreases the number of time slots for inter-road communication (step S32).

  When the process of step S32 is completed, or when it is determined that there are not insufficient time slots (step S31: NO), the control unit 12 determines whether or not there are remaining time slots, for example, the traffic volume is a predetermined traffic volume. It is determined whether it is less than (step S33). When it is determined that the traffic volume is less than the predetermined traffic volume (step S33: YES), the control unit 12 increases the number of time slots for road-to-road communication, for example, changes to the standard number of time slots (step S34). . The predetermined traffic volume and the standard number of time slots are stored in the storage unit 13 of the roadside communication device 1.

  When the process of step S34 is completed, or when it is determined that the traffic volume is equal to or greater than the predetermined traffic volume (step S33: NO), the control unit 12 is based on the communication state information acquired by monitoring the inter-vehicle communication. Then, the quality of the communication state by the in-vehicle communication device 3 is determined (step S35). When it is determined that the communication state is poor (step S35: YES), the control unit 12 increases the number of time slots for road-to-vehicle communication (step S36).

  Preferably, in step S36, the number of time slots is increased so that the optimal time slot interval at which the in-vehicle communication device 3 can easily receive the information transmitted from the roadside communication device 1 is obtained.

  When the process of step S36 is completed, or when it is determined that the communication state is not defective (step S35: NO), the control unit 12 is in a good state in which the communication state of the in-vehicle communication device 3 is normalized. Is determined (step S37). When it is determined that the communication state is good (step S37: YES), the number of time slots for road-to-vehicle communication is reduced, for example, changed to the standard number of time slots (step S38).

  When the process of step S38 is completed or when it is determined that the wireless communication state is not good (step S37: NO), the control unit 12 determines time slot allocation, and determines the determined time slot allocation result. The in-vehicle communication device 3 and the roadside communication device 1 are notified (step S39), and the subroutine processing relating to the time slot assignment change is completed.

  As shown in FIG. 5, when the process of step S14 is completed, or when it is determined in step S13 that there is no time slot request (step S13: NO), the control unit 12 responds to the traffic information and the emergency information. A subroutine for selecting the selected table is called to select the tables 14a, 14b, and 14c according to the traffic volume and the presence or absence of an emergency (step S15).

  FIG. 8 is a flowchart showing a processing procedure of a subroutine related to table selection. The control unit 12 determines whether or not there is an emergency based on the emergency information acquired in step S12 (step S51). When it determines with it being an emergency (step S51: YES), the control part 12 selects the table 14c which concerns on an emergency (step S52), and complete | finishes the process which concerns on a table selection.

  When it determines with not having an emergency (step S51: NO), the control part 12 determines whether traffic volume is larger than predetermined traffic volume based on traffic volume information (step S53). When it determines with there being much traffic (step S53: YES), the control part 12 selects the table 14b which concerns smoothly (step S54), and complete | finishes the process which concerns on table selection.

  If it is determined that the traffic volume is low (step S53: NO), the control unit 12 selects the table 14a related to safety (step S55), and ends the process related to table selection.

  As shown in FIG. 5, when the process of step S15 is completed, a subroutine is called to select information to be included in each time slot (step S16).

  FIG. 9 is a flowchart showing a processing procedure of a subroutine related to information selection. Based on the tables 14a, 14b, and 14c selected in step S15, the control unit 12 assigns information having a predetermined transmission priority or higher, for example, information within the top five transmission priorities to all the time slots (step S71). . Next, the control unit 12 compares the amount of information to be transmitted with the number of assigned time slots to determine whether or not there are insufficient time slots (step S72).

  When it is determined that the time slot is not insufficient (step S72: NO), the control unit 12 determines whether or not the communication state is good (step S73). When it is determined that the communication state is good (step S73: YES), the control unit 12 distributes and assigns information having a transmission priority lower than the predetermined transmission priority, for example, information of the transmission priority higher-ranked 6th or later to each time slot ( Step S74), the process related to information selection is finished.

  When it is determined that the time slot is insufficient (step S72: YES), or when it is determined that the communication state is poor (NO in step S73), the control unit 12 sets the information less than the predetermined transmission priority. Among them, only a part of the information is distributed and allocated to each time slot (step S75), and the process related to information selection is finished.

Through the above processing, transmission information can be created so that the number of continuous transmissions of information having a high transmission priority is increased and the number of continuous transmissions of information having a low transmission priority is decreased. That is, information with a high transmission priority is transmitted in a large number of time slots, and information with a low transmission priority is transmitted in a small number of time slots.
For information with a high transmission priority, even if the time slot is insufficient or the communication state is poor, information is transmitted in a large number of time slots (maintaining the number of time slots), and the transmission priority is low. By reducing the number of time slots allocated to, important information can be preferentially transmitted.

  FIG. 10 is an explanatory diagram conceptually showing the content of information transmitted when the traffic volume is low. When the traffic volume is small, for example, there are six time slots assigned for road-to-vehicle communication in one cycle, and FIGS. 10A to 10F show the six time slots assigned to road-to-vehicle communication. Show. When the traffic volume is small, the control unit 12 selects the safety-related table 14a. Based on the table 14a, the control unit 12 assigns information having a transmission priority within the top five to all six time slots. The reason why information with a transmission priority of 5 or less is assigned to all the time slots is to ensure that information with a high transmission priority is transmitted to the in-vehicle communication device 3. In addition, when there is no shortage of time slots and the communication state is good, the control unit 12 distributes and assigns information with the transmission priority higher than the sixth to each time slot as shown in FIG. All information from the top six transmission priorities is allocated and allocated to each time slot because the traffic volume is small and the number of time slots allocated for road vehicles is large. This is because all the information can be transmitted without any problem if transmitted to. In addition, since the information of the transmission priorities 9-11 is not the transmission object between road vehicles, this information is not allocated to the time slot. When there is a margin in the number of time slots, all information can be transmitted, and information having a relatively high transmission priority can be transmitted multiple times even in one cycle. By selecting and distributing the information to be transmitted as shown in FIG. 10, it is possible to preferentially transmit information related to safety when the traffic volume is small.

  FIG. 11 is an explanatory diagram conceptually showing the contents of information transmitted when the traffic volume is large. When there is a large amount of traffic, for example, there are two time slots allocated for road-to-vehicle communication in one cycle. FIGS. 11A and 11B show two time slots allocated for road-to-vehicle communication. Show. The number of time slots allocated for road-to-vehicle communication decreases from 6 (in the case of FIG. 10) to 2 because the traffic volume increases and the number of time slots allocated for vehicle-to-vehicle communication increases. This is because the time slots allocated for communication are reduced. When there is much traffic, the control part 12 selects the table 14b regarding the smoothness of traffic. Based on the table 14b, the control unit 12 assigns the information with the transmission priority within the top five to all two time slots. The reason why information with a transmission priority of 5 or less is assigned to all the time slots is to ensure that information with a high transmission priority is transmitted to the in-vehicle communication device 3. Since the information with the transmission priority number 5 is not a transmission target, the information is not allocated to the time slot, and the information within the transmission priority number 5 is the transmission priority numbers 1 to 4 and 6. Information. Further, when the time slot is insufficient, the control unit 12, as shown in FIG. 11, some information among the information with the transmission priority of the sixth and subsequent transmissions, for example, the transmission priority upper 6th to 9th Only information (information with a transmission priority of 7 to 14) is distributed and assigned to each time slot. Since the number of time slots allocated for road-to-vehicle communication is small, information with low transmission priority (information with transmission priority 15 and subsequent) is excluded from transmission targets, and information with medium transmission priority in one cycle This is to transmit once. By selecting and distributing the information to be transmitted as shown in FIG. 11, it becomes possible to preferentially transmit information relating to smoothness that is important when the traffic volume is large. Further, by omitting information having a low transmission priority, it is possible to reliably transmit information having a high transmission priority.

  FIG. 12 is an explanatory diagram conceptually showing the contents of information transmitted when there is a lot of traffic and the reception state is bad. When there is a large amount of traffic, for example, there are two time slots allocated for road-to-vehicle communication in one cycle. FIGS. 12A and 12B show two time slots allocated for road-to-vehicle communication. Show. The number of time slots allocated for road-to-vehicle communication decreases from 6 (in the case of FIG. 10) to 2 because the traffic volume increases and the number of time slots allocated for vehicle-to-vehicle communication increases. This is because the time slots allocated for communication are reduced. When there is a shortage of time slots due to heavy traffic and the reception state is poor, the control unit 12 may select information to be transmitted more strictly and assign it to each time slot as shown in FIG. Specifically, the information with the transmission priority within the top five is assigned to all the two time slots, and the information with the transmission priority of the top six is thinned out so as not to be assigned to the time slot. The reason why information with a transmission priority of 5 or less is assigned to all the time slots is to ensure that information with a high transmission priority is transmitted to the in-vehicle communication device 3. Since the information with the transmission priority number 5 is not a transmission target, the information is not allocated to the time slot, and the information within the transmission priority number 5 is the transmission priority numbers 1 to 4 and 6. Information. In addition, since the number of time slots allocated for road-to-vehicle communication is small, information with low transmission priority (information with transmission priority No. 6 and later) is excluded from transmission targets, and information with high transmission priority is in-vehicle communication device This is because the data is reliably transmitted to 3.

FIG. 13 is an explanatory diagram conceptually showing the contents of information transmitted in an emergency situation. When the traffic volume is small, for example, there are six time slots allocated for road-to-vehicle communication in one cycle, and FIGS. 13A to 13F show the six time slots allocated for road-to-vehicle communication. Show. In an emergency situation, the control unit 12 selects the table 14c regarding the emergency situation. Based on the table 14c, the control unit 12 assigns information having a transmission priority within the top five to all six time slots. The reason why information with a transmission priority of 5 or less is assigned to all the time slots is to ensure that information with a high transmission priority is transmitted to the in-vehicle communication device 3. Further, when there is no shortage of time slots and the communication state is good, the control unit 12 displays information on the transmission priority of the sixth or higher (transmission priority 6 to 18) at each time as shown in FIG. Allocate and distribute to slots. All information from the top six transmission priorities is allocated and allocated to each time slot because the traffic volume is small and the number of time slots allocated for road vehicles is large. This is because all the information can be transmitted without any problem if transmitted to. In addition, since the information of the transmission priority 9, 10, 13, 14 is not the transmission object between road vehicles, this information is not allocated to the time slot. By selecting and distributing the information to be transmitted as shown in FIG. 13, it becomes possible to preferentially transmit important information in an emergency situation.
In an emergency, it may be configured not to permit allocation of time slots between vehicles, but to allocate all time slots between roads and road vehicles.

  In addition, although selection of the information transmitted from the roadside communication apparatus 1 to the vehicle-mounted communication apparatus 3 was demonstrated, the information transmitted between roadways can be selected similarly using table 14a, 14b, 14c.

  Next, the control unit 12 determines whether or not it is a predetermined transmission timing based on the timing result of the timing unit (step S17). When it determines with it not being a transmission timing (step S17: NO), the control part 12 returns a process to step S11. When it determines with it being a transmission timing (step S17: YES), the control part 12 transmits the information selected in step S16 to the vehicle-mounted communication apparatus 3 or the roadside communication apparatus 1 (step S18), and a process is step S11. Return to.

  In the communication system configured as described above, it is possible to preferentially transmit necessary information in each state by selecting the tables 14a, 14b, and 14c according to the traffic volume and the presence or absence of an emergency. In addition, the shortage of time slots for inter-vehicle or road-to-vehicle communication due to an increase in traffic can be indirectly solved. Therefore, wireless communication using the band can be performed effectively, and safe driving and smooth traffic can be supported even when the traffic volume increases. In addition, information for responding to an emergency can be reliably transmitted.

  Furthermore, when the communication state of the in-vehicle communication device 3 deteriorates, it is configured to refrain from transmitting information with a low transmission priority and preferentially transmit information with a high transmission priority. Information can be transmitted reliably, time slot shortage can be resolved indirectly, and stable safety support and smooth traffic can be achieved.

In the embodiment, information having a high transmission priority is configured to be assigned to all the time slots. More preferably, an optimum number of consecutive transmissions described later is selected from items having a high transmission priority. It is preferable to specify and assign information to the time slots so that the specified number of continuous transmissions is achieved.
FIG. 14 is a graph showing the relationship between traffic density and optimal time slot interval. The horizontal axis represents the traffic density (units / km), and the vertical axis represents the time slot interval (msec) at which the information reception probability by the in-vehicle communication device 3 is substantially maximum. The roadside communication device 1 measures the time slot interval at which the reception probability of the in-vehicle communication device 3 is substantially maximum based on the communication state information transmitted from the in-vehicle communication device 3, and the time slot interval at which the reception probability is approximately maximum. And the relationship with the traffic density is stored in the storage unit. According to FIG. 14, for example, when the traffic density is 90 [vehicles / km], the optimum time slot interval is 30 msec. The traffic density can be calculated or estimated based on the traffic volume.

Further, in the embodiment, the table selection and the time slot shortage are determined based on the traffic information indicating the traffic volume of the vehicle, but the information indicating the communication traffic of the in-vehicle communication device is determined. It may be configured to acquire and select a table and transmission information. Each in-vehicle communication device transmits the information amount of information to be transmitted, specifically storing the information amount of information to be transmitted in the header part, and the road-side communication device is transmitted and received by each in-vehicle communication device By monitoring the information to be performed, information indicating communication traffic of a plurality of in-vehicle communication devices traveling on the road can be obtained. Moreover, you may comprise so that this traffic information may be acquired from the memory | storage part which memorize | stored the number of time slots allocated to the vehicle-mounted communication apparatus as traffic information.
FIG. 15 is a graph showing the relationship between traffic volume and communication traffic. The horizontal axis indicates the traffic volume of the vehicle (unit / 5 minutes), and the vertical axis indicates the communication traffic (Erlang). When 10% of vehicles traveling on the road are equipped with an in-vehicle communication device, the traffic volume and communication traffic have a correlation as shown in FIG. 15 and are used for various communication processes shown in the embodiment. The traffic to be used can be replaced by communication traffic.
Specifically, as in the priority table shown in FIG. 4, the storage unit of the roadside communication device stores various items of information to be transmitted from the roadside communication device to the in-vehicle communication device, and transmission of each item when communication traffic is low. A priority table in which the transmission priority is associated with the transmission priority of each item when communication traffic is high is stored. The order of priority of transmission is the same as in FIG.
And the control part of a roadside communication apparatus acquires the information which shows communication traffic by step S12 of FIG. 5, changes allocation of a time slot according to the communication traffic which the acquired information shows, selects a table, transmission information Configure to select.
In addition, although the structure which changes allocation of a time slot according to traffic volume or communication traffic was demonstrated, you may be comprised so that allocation of a time slot may be changed according to each traffic volume and communication traffic.

  Furthermore, as the traffic information indicating the traffic volume of the vehicle, not only the traffic volume of the vehicle equipped with the in-vehicle communication device corresponding to the road-to-vehicle communication and the inter-vehicle communication, but also the conventional traffic volume measured by the sensor is used. May be. Also, the vehicle-mounted communication device mounting rate as a constant is stored, and the integrated value obtained by multiplying the traffic volume of the vehicle equipped with the vehicle-mounted communication device corresponding to road-to-vehicle communication and vehicle-to-vehicle communication by the vehicle-mounted communication device mounting rate. May be used as traffic information.

  Furthermore, not only the traffic volume of the vehicle traveling on the road but also the vehicle type may be determined and the traffic volume for each vehicle type may be acquired. This is because a high vehicle is more likely to obstruct wireless communication than a low standard vehicle. A table may be selected by weighting according to the number of high vehicle vehicles. In this case, a more optimal table according to the traffic situation can be selected, and important information can be preferentially transmitted.

  Furthermore, the transmission from the roadside communication device to the in-vehicle communication device employs broadcast communication that can effectively use the radio wave band, but is not necessarily limited thereto.

  Furthermore, although the communication system which employ | adopted the broadcast communication system as a communication system between road vehicles was demonstrated, you may employ | adopt an individual communication system, when there is a margin in a radio wave band.

  Furthermore, in the embodiment, the example in which multiplex wireless communication is performed by the time division multiple access method has been described, but the multiplex wireless communication method is not limited to this. For example, the present invention may be applied to FDM, OFDMA, CDM, other multiple radio communication schemes, or multiple radio schemes related to combinations of each scheme.

  Furthermore, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is explanatory drawing which shows notionally the communication system which concerns on embodiment of this invention. It is explanatory drawing which shows notionally an example of the data format of the information which a roadside communication apparatus and a vehicle-mounted communication apparatus transmit / receive in a time slot. It is a block diagram which shows the structure of a communication system. It is explanatory drawing which shows a priority table notionally. It is a flowchart which shows the process sequence of the control part which concerns on the radio | wireless communication of a roadside communication apparatus. It is explanatory drawing which shows an example of the allocated time slot notionally. It is a flowchart which shows the process sequence of the subroutine which concerns on the allocation change of a time slot. It is a flowchart which shows the process sequence of the subroutine which concerns on table selection. It is a flowchart which shows the process sequence of the subroutine which concerns on information selection. It is explanatory drawing which shows notionally the content of the information transmitted when there is little traffic. It is explanatory drawing which shows notionally the content of the information transmitted when there is much traffic. It is explanatory drawing which shows notionally the content of the information transmitted when there is much traffic and a receiving state is also bad. It is explanatory drawing which shows notionally the content of the information transmitted in the case of an emergency. It is a graph which shows the relationship between traffic density and the optimal time slot interval. It is a graph which shows the relationship between traffic volume and communication traffic.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roadside communication apparatus 2 Traffic control center 3 In-vehicle communication apparatus 4 Optical beacon 5 Image sensor 6 Signal lamp 10, 30 Antenna 11, 31 Communication part 12,32 Control part 13,33 Storage part 14 Priority table (priority data)
14a, 14b, 14c tables (priority data elements)
B1, B2 Intersection C Vehicle R Road

Claims (8)

A roadside communication device installed along a road, and a vehicle-mounted communication device mounted on each of a plurality of vehicles traveling on the road, the roadside communication device between each vehicle-mounted communication device, and the roadside communication device, A communication system that allocates a plurality of radio resources for performing multiplex radio communication between the in-vehicle communication devices,
The roadside communication device is
Storage means for storing priority data indicating the transmission priority of each of a plurality of types of information to be transmitted to the in-vehicle communication device;
A selection unit based on the previous SL priority data to which the storage means stores, selects information to be included in each radio resource,
Means for acquiring communication status information indicating whether the communication status of the in-vehicle communication device is good or bad;
With
The selection means includes
When the communication state indicated by the acquired communication state information is poor, the amount of information with high transmission priority to be included in each radio resource is increased, the amount of information with low transmission priority is decreased, and the acquired communication When the communication state indicated by the state information is good, the amount of information with high transmission priority to be included in each radio resource is decreased and the amount of information with low transmission priority is increased. Communications system.   The roadside communication device is
  An acquisition means for acquiring information indicating at least one of a traffic volume of a vehicle and communication traffic of the in-vehicle communication device;
  The selection means includes
  Information to be included in each radio resource is selected based on at least one of the traffic volume and communication traffic indicated by the information acquired by the acquisition means and the priority data.
  The communication system according to claim 1. The priority data is
A plurality of priority data elements indicating different transmission priorities depending on the traffic volume or communication traffic,
The selection means includes
A priority data element corresponding to the traffic volume or communication traffic acquired by the acquisition means is selected, and information to be included in each radio resource is selected based on the selected priority data element. The communication system according to claim 2 . Before Symbol roadside communication device,
With emergency information obtaining means for obtaining emergency information about the emergency situation,
The selection means is
Emergency information acquired by the emergency information acquisition unit, and on the basis of the priority data is so as to select the information to be included in each radio resource
Communication system according to any one of claims 1 to 3, characterized and this. The priority data is
A plurality of priority data elements indicating different transmission priorities according to emergency information,
The selection means includes
Select the priority data element corresponding to the acquired emergency information, according to claim 4 based on the selected priority data elements, characterized in that you have to select the information to be included in each radio resource The communication system according to 1. The selection means includes
The communication according to any one of claims 1 to 5 , wherein each radio resource includes more information having a higher transmission priority than information having a lower transmission priority. system. A roadside communication device installed along a road, and a vehicle-mounted communication device mounted on each of a plurality of vehicles traveling on the road, the roadside communication device between each vehicle-mounted communication device, and the roadside communication device, A wireless communication method for allocating a plurality of wireless resources for performing multiplex wireless communication between the in-vehicle communication devices,
Prepare priority data indicating the transmission priority of each of multiple types of information to be transmitted to the in-vehicle communication device,
Obtaining communication state information indicating the quality of the communication state of the in-vehicle communication device;
Based on the previous SL priority data, if the communication state indicated by the acquired communication state information is bad, increasing the amount of transmit high priority information should be included in each radio resource, transmission priority is low information When the communication state indicated by the acquired communication state information is good, the amount of information with high transmission priority to be included in each radio resource is decreased, and the amount of information with low transmission priority is increased. As described above, the wireless communication method is characterized by selecting information to be included in each wireless resource. A communication device that allocates a plurality of radio resources for performing multiplex radio communication between a plurality of mobile communication devices and between the mobile communication devices to the mobile communication device,
Storage means for storing priority data indicating the transmission priority of each of a plurality of types of information to be transmitted to the mobile communication device;
A selection unit based on the previous SL priority data to which the storage means stores, selects information to be included in each radio resource,
Means for acquiring communication status information indicating whether the communication status of the in-vehicle communication device is good or bad;
With
The selection means includes
When the communication state indicated by the acquired communication state information is poor, the amount of information with high transmission priority to be included in each radio resource is increased, the amount of information with low transmission priority is decreased, and the acquired communication When the communication state indicated by the state information is good, the amount of information with high transmission priority to be included in each radio resource is decreased and the amount of information with low transmission priority is increased. Communication device.

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