JP3832345B2 - Dynamic priority control method and roadside equipment constituting distributed system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a road traffic system composed of roadside equipment and vehicles installed along a road, and the roadside equipment that has received the message manages the transmission side roadside equipment information such as the information type and the reception side roadside equipment. The present invention relates to a priority control method that dynamically determines the urgency of a received message based on traveling state information and determines the priority of information to be transmitted to a vehicle according to the determined urgency of the information.
[0002]
[Prior art]
In the repeater that transmits a packet according to the priority of the received packet, in order to preferentially transmit the packet with the highest priority, the transmission side that transmits the packet to the repeater separates the priority from “ A priority control method for preferentially transmitting even packets with the same priority when the priority flag is set and a packet with the priority flag set is received by the repeater is described in, for example, Japanese Patent Laid-Open No. 7-336389 Has been.
[0003]
[Problems to be solved by the invention]
In the priority control method, the repeater could preferentially transmit a packet having a “priority flag” indicating that it is a packet having the highest priority even with the same priority packet. However, since the priority flag is set on the transmitting side that transmits the packet to the repeater, the repeater transmits the packet according to the reception order when receiving a plurality of packets with the priority flag set. Become. Therefore, when the priority control method is applied to a road traffic system, the roadside device preferentially transmits the most urgent information to the vehicle when receiving a plurality of urgent information for the driver such as traffic accident information. There was a problem that we could not guarantee.
[0004]
[Means for Solving the Problems]
In order to solve the above problem, the dynamic priority control method in the present invention is:
(1) Receive driving support information that requires urgency such as accident information and falling object information,
(2) Based on transmission information such as transmission source position information and information type given by the transmission side node, and traveling conditions such as vehicle position and vehicle speed managed by the reception side node,
(3) The receiving node calculates the urgency of the information, and determines the priority order of the information to be transmitted to the vehicle based on the calculated urgency.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described. FIG. 1 is an overall configuration diagram of an ITS (Intelligent Transport System) road-to-vehicle communication system that distributes information to two vehicles having different speeds. Multimedia information such as music and video is transmitted to the traveling vehicle from the Internet. It is assumed that a vehicle contact accident occurs and an obstacle falls on the road during delivery. The roadside device 101-1, the roadside device 101-2, and the roadside device 101-3 are connected to the roadside communication network 100, and each roadside device can communicate with each other via the roadside communication network 100.
[0006]
In addition, the roadside device 101-1, the roadside device 101-2, and the roadside device 101-3 can communicate with each other via a vehicle traveling on the road 120 via wireless communication. The repeater 102 is connected to the roadside communication network 100 and an external network 103 such as the Internet. A vehicle traveling on the road downloads multimedia information such as music and video via the roadside device and the repeater. Can do. The roadside communication network 100 is an optical fiber cable laid along, for example, a road.
[0007]
In the example of FIG. 1, when a vehicle 113 and a vehicle 114 traveling on the road 120 cause a collision accident, the roadside device 101-3 senses an impact sound by, for example, a sound sensor installed in the roadside device, and at the same time, An on-board camera captures a nearby image and performs image processing to detect the occurrence of a collision accident. Moreover, the camera mounted on the roadside device can recognize the fallen object even if the obstacle falls on the road by periodically updating the image of the road at a cycle of 1 second, for example. The roadside device 101-3 that has detected the vehicle accident transmits the accident information to other roadside devices via the roadside communication network 100.
[0008]
The roadside device 101-2 that has detected the fallen object transmits the fallen object information to other roadside devices via the roadside communication network 100. The roadside device 101-1 transmits accident information and fallen object information to the vehicle 111 and the vehicle 112 that travel at a speed 143 of V1 km / h and a speed 144 of V2 km / h by wireless communication. The wireless communication is, for example, a short-range wireless communication DSRC (Dedicated Short Range Communications) that performs two-way communication between a roadside device and a vehicle traveling on a road.
[0009]
FIG. 2 shows an example of a message flow when transmitting accident information, falling object information, and music information from the Internet to a vehicle traveling on the road. When the vehicle 113 and the vehicle 114 cause a collision accident, the roadside device 101-3 that has detected the accident is assigned to the accident information for each location of the roadside device 101-3, the service code indicating the information type, and the content of the message. A priority level and a message ID for identifying the message are given, and an accident information message 221 is broadcast to the roadside communication network 100.
[0010]
The information type is, for example, accident information, fallen object information, music information, or the like. The priority level is used to determine the transmission order of information to the roadside communication network, and information having a higher priority level is preferentially transmitted to the roadside communication network. For example, the highest priority level 0 is given to information indicating an obstacle on the road of accident information or fallen object information. The roadside device 101-2 that has detected the falling object 230 receives the position information of the roadside device 101-2, the service code indicating the information type, the priority level assigned to each message content, and the message ID for identifying the message. And the falling object information message 222 is broadcast to the roadside communication network 100.
[0011]
The repeater 102 gives the music information from the Internet a position ID of the repeater 102, a service code indicating the information type, a priority level assigned to each message content, and a message ID for identifying the message. Is broadcast to the roadside communication network 100.
[0012]
Each roadside device that has received the message determines the priority of the message to be transmitted to the vehicle based on the service code, the position information, and the priority level, and transmits the message from the high priority message to the vehicle. For example, the roadside device 101-1 having received the accident information message 221 and the fallen object information message 222 determines the priority of the accident information message and the fallen object information message based on the service code, the position information, the priority level, and the vehicle speed of the traveling vehicle. To decide. The roadside device 101-1 that has determined the transmission order of each message to each traveling vehicle transmits the falling object information 241 and the accident information 242 in the transmission order to the traveling vehicle 111, and the accident information 242 to the traveling vehicle 112. Then, the falling object information 241 is transmitted in the transmission order.
[0013]
The configuration of each roadside device is shown in FIG. The roadside device 101 includes a computer 350 that performs information processing, a wireless communication device 330 that performs wireless communication with a vehicle, and an external device 320 such as a camera or various sensors. The computer 350 is used as a processor 301 for performing operations such as program execution, a ROM 302 for storing basic programs and basic data such as an OS (Operating System), a processing area during program execution, and a temporary storage area for data. The RAM 303, a communication interface 311 for connecting to the roadside communication network 360, an external device interface 312 for exchanging data with an external device, and a communication interface 313 for exchanging data with a wireless communication apparatus, These components can exchange data with each other via the bus 310.
[0014]
The program executed on the processor 301 can communicate with one or a plurality of vehicles via the communication interface 313 and the wireless communication device 330, and other roadside devices via the communication interface 311 and the roadside communication network 100. And information such as external video, sound, vibration, temperature, humidity, and atmospheric pressure can be collected via the external device interface 312 and the external device 320. A program for executing the priority control method of the present invention is stored in the ROM 302, and packets transmitted to the vehicle are temporarily stored in a transmission buffer on the RAM 303. The stored transmission packet is processed by the processor 301, and the processed data is transmitted to the vehicle via the communication interface 313 and the wireless communication device 330.
[0015]
FIG. 4 (1) shows a priority control method functional block of each roadside device, and FIG. 4 (2) shows a priority control processing flow of each roadside device. The priority control unit 400 includes a reception unit 402, an urgency level determination unit 403, an urgency level management unit 404, and a transmission unit 405. The receiving unit 402 that has received the received message 401 determines from the service code table whether or not to receive the message based on the service code assigned to the message (step 411). The structure of the service code table is shown in FIG. The service code table 700 includes a service code 701 indicating the type of service and 702 indicating the contents thereof.
For example, accident information is registered in the service code 1. When the service code corresponding to the service code given to the received message is registered in the service code table, the receiving unit 402 receives the packet.
[0016]
Next, the emergency level determination unit 403 determines the emergency level by determining the emergency level function based on the service code given to the received message and the vehicle management table and the emergency level function table of the traveling vehicle connected via wireless communication. (Step 412). The urgency is an evaluation index indicating the degree of urgency of the message and takes a value of 0 <urgency <1. The higher the urgency, the higher the urgency of the message.
[0017]
The vehicle management table is shown in FIG. 8 (1), and the urgency level function table is shown in FIG. 8 (2). The vehicle management table 800 includes a vehicle ID 801 for identifying a traveling vehicle connected via wireless communication and a vehicle speed 802 indicating the speed of the vehicle. For example, the vehicle speed V1 is registered in the vehicle ID1, and the vehicle speed V2 is registered in the vehicle ID2. The urgency level function table 810 includes a service code 811 indicating the type of service, a vehicle speed 812 for determining the urgency level function, and an urgency level function 813 determined based on the vehicle speed range. For example, the emergency function F1 (D) is registered in the vehicle speed range 0 to 100 km / h of the service code 1. D is a variable for determining the degree of urgency, and represents the distance from the road failure occurrence site such as an accident.
[0018]
Next, the urgency level management unit 404 registers the message ID assigned to the message, the priority level, and the urgency level derived by the urgency level determination unit 403 in the urgency level management table, and a message with a high priority level and urgency level. The data are rearranged in order (step 413).
[0019]
The urgency level management table is shown in FIG. The urgency management table 1200 includes a transmission order 1201 indicating a message transmission order, a priority level 1202, a message ID 1203, and an urgency 1204. The urgency management table is managed for each vehicle. For example, a message of priority level 0, message ID 1, and urgency level 0.7 is registered in the transmission order 1 of the vehicle 1. When a new message is registered in the urgency management table for each vehicle, the messages are rearranged in the order of priority and urgency.
[0020]
The transmission unit 405 sequentially stores messages in a transmission buffer for each vehicle ID from a message having a low transmission order 1201 value in the urgency management table for each priority level, and transmits the message to each vehicle (step 414). A configuration example of the transmission buffer for each vehicle ID is shown in FIG. In the example of FIG. 12 (2), the transmission buffer for each vehicle ID is composed of the transmission buffer 1211 of the vehicle 1 and the transmission buffer 1212 of the vehicle 2, and messages are uniformly transmitted from the transmission buffer for each vehicle ID. Go.
[0021]
For example, a fallen object information message with an emergency level of 0.7 and an accident information message with an emergency level of 0.5 are stored in the transmission buffer of the vehicle 1, and an accident information message with an emergency level of 0.7 is stored in the transmission buffer of the vehicle 2. A falling object information message with an urgency level of 0.5 is stored. The message stored in the transmission buffer for each vehicle ID is a transmission message 406 transmitted from the urgency management table, and a vehicle ID for identifying the vehicle that transmits the message is given to the transmission message.
[0022]
FIG. 5 (1) shows the received message format, and FIG. 5 (2) shows the transmitted message format. The received message format 510 includes a service code 511 indicating an information type, a message ID 512 for identifying a message, 513 indicating position information of a transmission source side device, a priority level 514 given to each message content, and 515 indicating information content. Composed. The service code 511 is used to determine whether or not the reception unit 402 receives a message. When the service code 511 given to the reception message 510 is registered in the service code table, the service code 511 is received. To do.
[0023]
The message ID 512 is used to uniquely determine a message within the system, and includes, for example, a roadside device ID of a transmission source roadside device and a message sequence number transmitted by the roadside device. For example, (longitude, latitude) is given to the position information 513, and is used when the reception determination unit 403 calculates the distance D to the transmission source side device. The priority level 514 is a priority level for each message content given by the transmission source roadside device. The higher the priority level, the higher the priority order of the transmitted messages. For example, accident information, fallen object information, and music information are given to the information contents 515.
[0024]
The transmission message format 520 includes a vehicle ID 521 for identifying a vehicle and information content 515. Each roadside device determines a message destination vehicle based on the vehicle ID 521 and transmits a message. The information content 515 is the same as the information content of the received message format 510.
[0025]
FIG. 6 shows a processing flow of the urgency determination unit. When the receiving unit 402 determines that the received message 401 is received, the urgent level determining unit 403 determines an urgent level function from the service code, the vehicle management table, and the urgency level function table provided in the message (step 601). The distance D between the roadside devices of the message transmission source is calculated from the location information given in the location information and the location information of the own roadside device registered in the location information table in advance when the roadside device is installed (step 602). The urgency level E of the received message is determined from the determined urgency level function and the calculated distance D (step 603). FIG. 9 shows a configuration diagram of the position information table of each roadside device.
[0026]
The position information table 900 includes longitude information 901 and latitude information 902. The roadside device that has received the message receives the position information (longitude information and coordinate information of latitude information) given in the message and the coordinate information of the position information table. The distance D is calculated from In addition, since a computer such as a repeater is not installed on the road, NULL is registered.
[0027]
For example, when the roadside device 101-1 receives the accident information message 221 transmitted from the roadside device 101-3 and the fallen object information message 222 transmitted from the roadside device 101-2, the roadside device 101-1 receives wireless communication from the vehicle management table via wireless communication. The vehicle speed V1 and the vehicle speed V2 of the connected vehicle 1 and vehicle 2 are confirmed, and then the accident information service code 1, the emergency speed function F1 (D) of the vehicle speed V1, and the accident information service are checked from the emergency function table. Code 1, vehicle speed V2 urgency function F2 (D), fallen object information service code 2, vehicle speed V1 urgency function G1 (D), fallen object information service code 2, and vehicle speed V2 urgency function G2 (D) is determined, a distance D1 (141) with the roadside device 203 and a distance D2 (142) with the roadside device 202 are calculated, and the calculated distance D1 with the roadside device 203 is calculated. The distance D2 between the roadside device 202 and the roadside device 202 is determined based on the emergency information function F1 (D) of the accident information for the determined speed V1, the emergency function G1 (D) of the fallen information for the speed V1, and the emergency function of the accident information for the speed V2. By substituting F2 (D) and the urgency function G2 (D) of falling object information, the urgency E for the accident information and falling object information of the speed V1 and the speed V2 is determined.
[0028]
FIG. 10 (1) shows the urgency function of speed V1, and FIG. 10 (2) shows the urgency function of speed V2. For example, the urgency function is calculated by using the stopping distance S (V), which is the distance traveled by the vehicle between the braking stop distance and the brake reaction time described in the “Traffic Engineering Handbook” of the Traffic Engineering Research Foundation, and F (D) = -D / 10S (V) +1, G (D) =-D / 5S (V) +1, where S (V) is the driver's brake reflection time of 0.75 seconds, and the friction coefficient is a value considering safety. 0.07, S (V) = 0.208V + 0.056V ² And the horizontal axis has distance D and the vertical axis has urgency E. The emergency information function F1 (D) 1001 of accident information is a function that maximizes the emergency degree E at the accident occurrence point 1005, and F1 (D) = − D / 10S (V1) +1, and the emergency function of falling object information G1 (D) 1002 is a function that maximizes the degree of urgency E at the falling object point 1006, and G1 (D) = − D / 5S (V1) +1.
[0029]
For example, when the roadside device 101-1 receives the accident information message 221 and the fallen object information message 222, with respect to the distances D1 and D2 between the roadside device 101-3 and the roadside device 101-2 from the travel position 1007 of the vehicle 111, F1 (D1) = 0.7 and G1 (D2) = 0.5 are obtained. The traveling position of the vehicle 111 is a position of a roadside device that is connected to the vehicle 111 via wireless communication, for example, an installation position of the roadside device 101-1.
[0030]
The emergency level function F2 (D) 1011 of accident information is a function that maximizes the emergency level E at the accident occurrence point 1015, and F2 (D) = − D / 10S (V2) +1, and the emergency level function of falling object information G2 (D) 1012 is a function that maximizes the degree of urgency E at the falling object point 1016, and G2 (D) = − D / 5S (V2) +1. For example, when the roadside device 101-1 receives the accident information message 221 and the fallen object information message 222, with respect to the distance D1 and the distance D2 between the roadside device 101-3 and the roadside device 101-2 from the travel position 1017 of the vehicle 111. F2 (D1) = 0.5 and G2 (D2) = 0.7 are obtained. The traveling position of the vehicle 112 is the same as the traveling position of the vehicle 111 and is the installation position of the roadside device 101-3.
[0031]
FIG. 11 shows a processing flow of the urgency management unit. When the emergency level E for the received message 401 is determined by the emergency level determination unit 403, the message ID 512, the priority level 514, and the emergency level E are registered in the emergency level management table for each vehicle registered in the vehicle management table. (Step 1101). Next, the messages in the urgency level management table 1200 are rearranged in order of high priority level and high urgency level (step 1102), and the messages with the lowest transmission order values in the urgency level management table are stored in the transmission buffer for each vehicle ID. (Step 1103).
[0032]
For example, the message ID 1 and the emergency level E = 0.7 of the accident information message 221 are registered in the emergency level management table of the vehicle 1, and the message ID 2 and the emergency level E = 0.5 of the falling object information message 222 are the emergency level of the vehicle 1. The message ID 1 and emergency level E = 0.5 of the accident information message 221 are registered in the emergency level management table of the vehicle 2 and the message ID 2 and emergency level E = 0.7 of the fallen object information message 222 are registered in the emergency level management table. Is registered in the emergency management table of the vehicle 2. In the emergency level management table of the vehicle 1, the priority level of the accident information message and the priority level of the fallen object information message are the same, and the emergency level E = 0.7> the emergency level E = 0.5. In the transmission order 1 of the degree management table, the message ID 1 of the accident information message and the urgency E = 0.7 are stored, and in the transmission order 2 the message ID 2 of the fallen object information message and the urgency E = 0.5 are stored. Sorting is done.
[0033]
In the emergency level management table of the vehicle 2, the priority level of the accident information message and the priority level of the fallen object information message are the same, and the emergency level E = 0.5 <the emergency level E = 0.7. In the transmission order 1 of the degree management table, the message ID 2 of the fallen object information message and the urgency E = 0.7 are stored, and in the transmission order 2 the message ID 1 of the accident information message and the urgency E = 0.5 are stored. Sorting is done. Next, according to the transmission order 1201 of the emergency level management table 1200, the accident information message 221 with the emergency level E = 0.7 and the fallen object information message 222 with the emergency level E = 0.5 are stored in the transmission buffer 1211 of the vehicle 1. Then, the accident information message with the emergency level E = 0.5 and the falling object information message with the emergency level E = 0.7 is stored in the transmission buffer 212 of the vehicle 2. The transmission message 406 stored in the transmission buffer for each vehicle ID is transmitted to the vehicle ID 521 uniformly assigned to the transmission message.
[0034]
In the ITS road-to-vehicle communication system, when multimedia information such as music and video is distributed from the Internet to the traveling vehicle, if a vehicle contact accident occurs and an obstacle falls on the road, the speed of traveling on the road The priority control method of the roadside device that transmits information to a plurality of different vehicles has been described. The roadside device that has received the accident information message and the fallen object information message has the urgency level of the urgency level function table in which the urgency level of each message is registered in advance in the roadside device based on the traveling state such as the vehicle position and the vehicle speed. The information is determined from the function, and information is transmitted to each traveling vehicle in order from the information of high urgency.
[0035]
Accordingly, when a plurality of messages having the same priority level are received, the message for each traveling vehicle is not transmitted based on the urgency level of the message with respect to the vehicle position and the vehicle speed, instead of transmitting information based on the order of reception of the messages. Therefore, a message with higher urgency can be preferentially transmitted even for a message received later, and safe and appropriate information distribution can be performed to the driver.
[0036]
Next, a second embodiment will be described. In the first embodiment, since the road surface condition of the road is constant, even if the road surface condition has changed due to weather changes such as a sunny day or a rainy day, the priority order of messages sent to the vehicle is changed. Not. When the friction coefficient of the road surface changes depending on the road surface condition, the distance traveled from the time the driver steps on the brakes until the vehicle stops varies, so a priority control method that considers the road surface condition is necessary to deliver more appropriate information. It is. In the second embodiment, a priority control method that considers the vehicle position, the vehicle speed, and the road surface condition will be described.
[0037]
The overall configuration diagram of the ITS road-to-vehicle communication system that distributes information in consideration of the road surface condition is the same as the overall configuration diagram of FIG. 1. For example, “Furukawa Electric Time Report No. 105 Development of Road Wet Sensor System” The roadside device 101-1, the roadside device 101-2, and the roadside device 101-3 periodically receive road surface information via the roadside communication network 100. Can do.
[0038]
FIG. 13 shows a priority control processing flow of each roadside device. The priority control method functional block of each roadside device is the same as that in FIG. The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether or not to receive the message based on the service code assigned to the message (step 1311).
[0039]
Next, the emergency level determination unit 403 determines an emergency level function based on the service code given to the received message, the vehicle management table, the road surface management table, and the emergency level function table of the traveling vehicle being connected via wireless communication. The degree of urgency is determined (step 1312). The vehicle management table is the same as in FIG. The road surface management table is shown in FIG. 15 (1), and the urgency level function table is shown in FIG. 15 (2). The road surface management table 1500 includes road surface information 1501 indicating a road surface state, a friction coefficient 1502, and a current state 1503 for identifying the current road surface state.
[0040]
For example, when road surface information is received from a road surface sensor embedded in the road 120 at regular intervals of one hour interval, the corresponding road surface state is searched from the road surface information 1501 of the road surface management table 1500, and the current state 1503 of the corresponding road surface information is displayed. Set the flag to 1 and set the other current states to 0. For example, the friction coefficient of the road surface information “dry” is μ1, and 1 is set in the current state, indicating that the current road surface is in a dry state. The table format of the urgency level function table 1510 is the same as that shown in FIG. 8B, and the urgency level function 1513 is set with an urgency level function considering the friction coefficient. For example, the urgency function F1 (D) (μ) is registered in the vehicle speed range 0 to 100 km / h of the service code 1. μ represents the friction coefficient determined from the current road surface condition.
[0041]
Next, the emergency level management unit 404 registers the message ID assigned to the message and the emergency level derived by the emergency level determination unit 403 in the emergency level management table for each vehicle. The transmission order is rearranged (step 1313).
[0042]
The transmission unit 405 sequentially stores messages in the transmission buffer for each vehicle ID from the message with the lowest value in the transmission order 1201 in the urgency management table for each vehicle, and transmits the message to each vehicle (step 1314). The urgency management table is the same as that shown in FIG. A configuration example of the transmission buffer for each vehicle ID is the same as that in FIG. The message format of the transmission message 406 stored in the transmission buffer for each vehicle ID is the same as that in FIG.
[0043]
FIG. 14 shows a processing flow of the urgency determining unit. If the receiving unit 402 determines that the received message 401 is received, the urgent level determining unit 403 determines an urgent level function for each traveling vehicle from the service code given in the message, the vehicle management table, and the urgent level function table (step 1401), the friction coefficient μ of the road surface at the time when the message is received from the road surface management table is determined (step 1402), and the position information given in the message and the self-registered information in the position information table in advance when the roadside device is installed. The distance D is calculated from the position information of the roadside device (step 1403), and the urgency E of the received message is determined from the determined urgency function, the road friction coefficient μ, and the calculated distance D (step 1404).
[0044]
The position information table registered in the roadside device is the same as the position information table 900 of FIG. The urgency function is F (D) using, for example, a stop distance S (V) that is a distance traveled by the vehicle between the brake stop distance and the brake reaction time described in the “Traffic Engineering Handbook” of the Traffic Engineering Research Foundation. = −D / 10S (V) +1, G (D) = − D / 5S (V) +1, where S (V) = 0, where the brake reflection time of the driver is 0.75 seconds. .208V + 0.014V ² / Μ, with the distance D on the horizontal axis and the urgency E on the vertical axis.
[0045]
In the ITS road-to-vehicle communication system, when multimedia information such as music and video is distributed from the Internet to traveling vehicles, if a vehicle contact accident occurs and an obstacle falls on the road, the vehicle travels on the road. The priority control method of the roadside device that transmits information to a plurality of vehicles having different speeds has been described. The roadside device that has received the accident information message and the fallen object information message has an urgency function table in which the urgency level of each message is registered in advance in the roadside device based on the driving state such as the vehicle position, vehicle speed, and road surface condition. The information is transmitted to each traveling vehicle in order from the information of high urgency. As a result, when a plurality of messages having the same priority level are received, instead of transmitting information based on the order in which the messages are received, each travel is performed based on the urgency level of the message with respect to the vehicle position, vehicle speed, and road surface condition. Since the transmission order of messages to the vehicle is determined, messages with higher urgency can be preferentially transmitted even for messages received later, and vehicle slip due to sudden braking caused by delay in information distribution Etc. can be avoided in advance.
[0046]
Next, a third embodiment will be described. In the first and second embodiments, since it is assumed that the vehicle density is low, the priority order of messages to be transmitted to the vehicle is not changed even when the vehicle density such as traffic congestion is high. If traffic congestion occurs before the vehicle arrives at the site due to the impact of a road fault such as an accident, a new risk of rear-end collision will occur. A priority control method that considers In the third embodiment, a priority control method that considers vehicle position, vehicle speed, road surface information, and vehicle density will be described.
[0047]
An overall configuration diagram of an ITS road-to-vehicle communication system that distributes information in consideration of vehicle density is the same as the overall configuration diagram of FIG. 1, and a contact-type road surface sensor is embedded in the road 120, and the roadside equipment 101 -1, the roadside device 101-2 and the roadside device 101-3 measure the vehicle density from the number of communication channels in communication connection, and periodically broadcast the vehicle density information to the roadside communication network 100. Each roadside device can periodically receive road surface information via the roadside communication network 100.
[0048]
FIG. 16 shows a priority control processing flow of each roadside device. The functional block diagram of the priority control method for each roadside device is the same as FIG. The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether or not to receive the message using the service code assigned to the message (step 1611).
[0049]
Next, the urgency level determination unit 403 determines the urgency level based on the service code given to the received message, the vehicle management table, the road surface management table, the vehicle density table, and the urgency level function table of the traveling vehicle connected via wireless communication. A function is determined and the urgency level is determined (step 1612). The vehicle management table is the same as in FIG. The road surface management table is the same as FIG. The urgency level function table is the same as FIG. A vehicle density table is shown in FIG. The vehicle density table 1800 includes a roadside device ID 1801 that measures the vehicle density, position information 1802 of the measured roadside device, and a measured vehicle density 1803. The vehicle density ρ is the number of vehicles that travel in the communication area per unit time, and is represented by ρ = M / T.
[0050]
M is the total number of vehicles that have communicated with the roadside device at time T, and time T is a fixed period of time during which the vehicle density message is transmitted to the roadside communication network. For example, the position information of the roadside device 101-3 is (longitude 3, latitude 3), and the vehicle density measured by the roadside device 101-3 is ρ3. The position information of the roadside device is information from the position information table of each roadside device, and the longitude information and the latitude information are the same as the longitude information 901 and the latitude information 902 in FIG. Next, the emergency level management unit 404 registers the message ID assigned to the message and the emergency level derived by the emergency level determination unit 403 in the emergency level management table for each vehicle. Rearrangement is performed in order (step 1613).
[0051]
In the transmission unit 405, messages are sequentially stored in the transmission buffer for each vehicle ID from the message having the lowest transmission order 1201 in the urgency management table for each vehicle, and the message is transmitted to each vehicle (step 1614). The urgency management table is the same as that shown in FIG. A configuration example of the transmission buffer for each vehicle ID is the same as that in FIG. The message format of the transmission message 406 stored in the transmission buffer for each vehicle ID is the same as that in FIG.
[0052]
FIG. 17 shows a processing flow of the urgent level determination unit. If the receiving unit 402 determines that the received message 401 is received, the urgent level determining unit 403 determines an urgent level function for each traveling vehicle from the service code given in the message, the vehicle management table, and the urgent level function table (step 1701), the friction coefficient μ of the road surface at the time when the message is received from the road surface management table is determined (step 1702), and the position information given in the message and the self-registered information in the position information table in advance when the roadside device is installed. The distance D is calculated from the position information of the roadside device (step 1703).
[0053]
Next, the distance D and the distance Di between all the roadside devices registered in the vehicle density table are compared, and all the vehicle densities ρi and the safe vehicle density ρs satisfying D> Di are compared with the vehicle density table. Based on the vehicle density table (step 1704). The vehicle density ρi is a vehicle density for the roadside device ID = i registered in the vehicle density table. The distance Di is the distance between the roadside device that measured the vehicle density ρi and the roadside device that received the message. The safe vehicle density ρs is a safe vehicle density on the assumption that the vehicle interval is sufficiently maintained and no vehicle accidents such as rear-end collisions occur, and is registered as a safe vehicle density table in the roadside equipment. Yes.
[0054]
The distance at which the vehicle interval is sufficiently maintained is, for example, 100 m or more. A safe vehicle density table is shown in FIG. In the safe vehicle density table 1810, a value indicating the safe vehicle density is registered. For example, 0.02 is registered. The safe vehicle density table 1810 is registered when the roadside device is installed on the road. As a result of comparison of all vehicle densities ρi registered in the vehicle density table with the safe vehicle density ρs (step 1705), if there is ρi that satisfies ρi> ρs, the minimum is selected from the distances Di. This distance Di is used as the distance D used in the urgency function (step 1706). If ρ i <= ρ s for all ρ i, the distance D calculated when the message is received is set as the distance D used in the urgency function (step 1707). Finally, the urgency E of the received message is determined from the determined urgency function, the friction coefficient μ, and the determined distance D (step 1708). The urgency function is the same as the urgency function shown in the second embodiment.
[0055]
In the ITS road-to-vehicle communication system, when multimedia information such as music and video is distributed from the Internet to traveling vehicles, if a vehicle contact accident occurs and an obstacle falls on the road, the vehicle travels on the road. The priority control method of the roadside device that transmits information to a plurality of vehicles having different speeds has been described. The roadside device that has received the accident information message and the fallen object information message is urgent in which the urgency of each message is registered in advance in the roadside device based on the vehicle position, vehicle speed, road surface condition, vehicle density, and other driving conditions It determines from the urgency function of a degree function table, and transmits information with respect to each traveling vehicle in order from information with high urgency. As a result, when a plurality of messages having the same priority level are received, information is not transmitted based on the order in which the messages are received, but based on the urgency of the message with respect to the vehicle position, vehicle speed, road surface condition, and vehicle density. In order to determine the transmission order of messages for each traveling vehicle, even messages received later can be preferentially transmitted even when the vehicle ahead is congested. However, it is possible to avoid the risk of a rear-end collision or the like due to information delivery delay in advance. In this embodiment, each roadside device connected to the roadside communication network uses vehicle density information calculated based on the number of vehicles in communication connection. For example, VICS (Vehicle Information & Communication System) or road The traffic information from the traffic information center may be used.
[0056]
Next, a fourth embodiment will be described. In the first, second, and third embodiments, since a straight road is assumed, priority is given to messages sent to the vehicle even when the vehicle does not pass through the road fault occurrence site such as an accident due to road branching. The rank is not changed. If the vehicle does not pass through the failure site, it is not always necessary to treat the driving support information as the most urgent information, so a priority control method that considers the moving route of the vehicle is necessary to deliver safer and more appropriate information. is there. In the fourth embodiment, a priority control method that takes into account the vehicle position, vehicle speed, road surface information, vehicle density, and further the vehicle movement route will be described.
[0057]
FIG. 19 is an overall configuration diagram of an ITS road-to-vehicle communication system that distributes information in consideration of a movement route, and assumes a case where a vehicle collision accident occurs on a branch destination road. The roadside device 101-1, the roadside device 101-2, the roadside device 101-3, the roadside device 101-4, and the roadside device 101-5 are connected to the roadside communication network 100, and each roadside device is mutually connected via the roadside communication network 100. Can communicate. The repeater 102 is connected to the roadside communication network 100 and an external network 103 such as the Internet. The vehicle 111 can download multimedia information such as music and video via the roadside device and the repeater. . In the example of FIG. 19, when a vehicle 113 and a vehicle 114 traveling on the road 120 cause a collision accident, the roadside device 101-5 that senses the vehicle accident sends the accident information to other roadside devices via the roadside communication network 100. Send. The roadside device 101-1 that has received the accident information transmits the accident information to the vehicle 111 that travels at a speed 143 of V1 km / h by wireless communication. Further, a road surface sensor for identifying the road surface state is embedded in the road 120.
[0058]
FIG. 20 shows an example of a message flow when the accident information is transmitted to a vehicle traveling on the road. When the vehicle 113 and the vehicle 114 cause an accident, the roadside device 101-5 that has detected the accident is assigned to the accident information, the location information of the roadside device 101-5, the service code indicating the information type, and the content of the message. A priority level, a message ID for identifying the message, and a road attribute ID for identifying the attribute of the road on which the roadside device 101-5 is installed are given, and the accident information message 221 is broadcast to the roadside communication network 100. The road attribute ID is for identifying, for example, a road name where the roadside device is installed. The roadside device that has received the message identifies where the transmission source roadside device is installed by the road attribute ID. be able to.
[0059]
As in the second and third embodiments, each roadside device can periodically receive road surface information from the roadside communication network 100, and the measured vehicle density information traveling in its own communication area can be obtained from the roadside communication network. Broadcast to 100. Each roadside device that has received the accident information message sends a message to the vehicle based on the service code, position information, priority level, position information managed by the own roadside device, vehicle speed information, vehicle density information, road surface information, and route information. Priorities are determined and sent to the vehicle from a high priority message. For example, the roadside device 101-1 that has received the accident information message 221 manages the priority of the accident information message by the service code, the location information of the roadside device 101-5, the priority level of the accident information message, and the roadside device 101-1. The position information, the vehicle speed information of the vehicle 111, the vehicle density information of the road 120 at the time of receiving the message, the road surface information of the road 120, and the route information of the vehicle 111 are determined. The roadside device 101-1 having determined the message transmission order transmits the accident information 242 to the traveling vehicle 111. The configuration of each roadside device is the same as in FIG.
[0060]
FIG. 21 shows a priority control processing flow of each roadside device. The priority control method functional block of each roadside device is the same as that in FIG. The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether or not to receive the message based on the service code assigned to the message (step 2101).
[0061]
Next, the urgency determination unit 403 stores the service code given to the received message, the vehicle management table, the road surface management table, the vehicle density table, the route management table, and the urgency level function table of the traveling vehicle connected via wireless communication. An urgency level function is determined based on the urgency level (step 2102). The vehicle management table is the same as in FIG. The road surface management table is the same as FIG. The urgency level function table is the same as FIG. The vehicle density table is shown in FIG. 24 (1), and the route management table is shown in FIG. 24 (2). The vehicle density table 2400 includes a roadside device ID 1801 that measures the vehicle density, position information 1802 of the measured roadside device, a measured vehicle density 1803, and a road attribute ID 2401 where the measured roadside device is installed. For example, the position information of the roadside device 101-3 is (longitude 3, latitude 3), the vehicle density measured by the roadside device 101-3 is ρ3, and the road attribute ID where the roadside device 101-3 is installed is 2. is there. The route management table 2410 includes a vehicle ID 2411 that is an identifier of a vehicle traveling in the communication area, route information 2412 that indicates a road attribute of a traveling route of the vehicle ID 2411, and a road attribute ID 2413 that identifies a road attribute indicated in the route information. Is done. For example, the vehicle ID 1 follows a route passing through the A line to the north, and the destination road attribute ID is 1.
[0062]
Next, the emergency level management unit 404 registers the message ID assigned to the message and the emergency level derived by the emergency level determination unit 403 in the emergency level management table for each vehicle. Rearrangement is performed in order (step 2103).
[0063]
The transmission unit 405 sequentially stores messages in a transmission buffer for each vehicle ID from a message having a low value in the transmission order 1201 in the urgency management table for each vehicle, and transmits the message to each vehicle (step 2104). The urgency management table is the same as that shown in FIG. A configuration example of the transmission buffer for each vehicle ID is the same as that in FIG. The message format of the transmission message 406 stored in the transmission buffer for each vehicle ID is the same as that in FIG.
[0064]
FIG. 22 (1) shows a received message format, and FIG. 22 (2) shows a route information table held by each roadside device. The received message format 2200 includes a service code 511 that indicates an information type, a message ID 512 that identifies a message, 513 that indicates location information of a source roadside device, a priority level 514 that is assigned to each message content, and a road attribute of a road Road attribute ID 2201 and 515 indicating information contents. The service code 511, message ID 512, location information 513, priority level 514, and information content 515 are the same as the received message format in FIG. The road attribute ID 2101 is used by the urgency determination unit 403, and the roadside device that has received the message compares the road where the roadside device is installed with the road attribute ID of the message transmission source, for example, an accident or the like. It can be determined whether or not a road fault has occurred on the same road. The road attribute ID is uniquely determined by each road. If the road attribute ID is the same road and there are a plurality of branches, the road attribute ID to the location information of the source roadside device relative to the location information of the own roadside device is added. Compared to the travel path of the vehicle by considering the direction vector.
[0065]
For example, when transmitting a message to a vehicle heading northward on line A, if the source roadside device of the received message is a roadside device on line A, the direction vector of the transmitting side roadside device relative to the receiving side roadside device is By considering, for example, it is possible to determine whether the message is from the north or the west of the same road. The route information table 2210 includes a road attribute 2211 indicating a road attribute and a road attribute ID 2212 for identifying the road attribute. The route information table is held by all roadside devices connected to the roadside communication network, and is given a road attribute ID 2212 when a message is sent to the roadside communication network.
[0066]
A road attribute 2211 is a road name in which a roadside device that holds a route information table is set, and is associated with a road attribute ID 2212. For example, a roadside device is installed on a road having a road attribute of No. A and a road attribute ID of 1.
[0067]
FIG. 23 shows a processing flow of the urgent level determination unit. When the receiving unit 402 determines that the received message 401 is received, the urgency determining unit 403 compares the road attribute ID of the message given in the message with the road attribute ID of the route management table (step 2301). The process according to the process flow shown in FIG. 17 is performed. If they are not the same, the vehicle density ρi of all roadside devices registered in the vehicle density table is compared with the safe vehicle density ρs based on the vehicle density table and the safe vehicle density table (step 2302) and registered. When ρi <= ρs for all ρi that have been set, the urgency E takes a constant value such as E = 0.4 (step 2303). The safe vehicle density table is the same as FIG. If there is ρi such that ρi> ρs, the road attribute ID for ρi is compared with the road attribute ID given to the received message (step 2304). E takes a constant value (step 2303).
[0068]
When ρi having the same road attribute ID as the road attribute ID assigned to the received message is registered, it is registered in the vehicle management table from the service code, vehicle management table, and emergency level function table given in the message. The urgency function for each traveling vehicle is determined (step 2305), the friction coefficient μ at the time when the message is received from the road surface management table is determined (step 2306), and all roadside devices having the vehicle density ρi The distance Di is calculated from the position information in the vehicle density table and the position information table held by the own roadside device, and Di that takes the minimum value among all the calculated distance Di is set as the distance D used in the urgency function ( Step 2307).
[0069]
Finally, the urgency level E of the received message is determined from the determined urgency level function, the friction coefficient μ, and the distance D (step 2308). The vehicle management table is the same as FIG. The road surface management table is the same as FIG. The urgency level function table is the same as FIG. The position information table held by the roadside device is the same as in FIG. The urgency function is the same as the urgency function shown in the second embodiment.
[0070]
In an ITS road-to-vehicle communication system, if a vehicle contact accident occurs on a branch road while delivering multimedia information such as music and video to the traveling vehicle via the Internet, the vehicle traveling on the road On the other hand, the priority control method of the roadside device that transmits information has been described. The roadside device that has received the accident information message is based on the vehicle position, the vehicle speed, the road surface state, the vehicle density, the travel state such as the travel route, etc. The information is determined from the urgency function, and information is transmitted to the traveling vehicle in order from the information with high urgency.
[0071]
As a result, when a plurality of messages having the same priority level are received, information is not transmitted based on the order in which the messages are received, but the urgency of the message with respect to the vehicle position, the vehicle speed, the road surface condition, the vehicle density, and the movement route. In order to determine the transmission order of messages to the traveling vehicle based on the information, if a road fault such as an accident occurs at a point different from the traveling route of the vehicle, the information is really urgent based on the moving route of the vehicle To avoid non-emergency information as urgent information, for example, avoid driving problems such as driver confusion and impatience, and preferentially handle information that does not affect the driver Therefore, it is possible to avoid resource overhead such as road-to-vehicle communication band.
[0072]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to implement | achieve the information provision according to the state of the vehicle.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a road traffic system including a priority control method according to the present invention.
FIG. 2 is a message flow when accident information, fallen object information, and multimedia information are mixed.
FIG. 3 is a configuration diagram of a roadside device.
FIG. 4 is a processing flow of a priority control unit according to the present invention.
FIG. 5 is a message format of a transmission message and a reception message.
FIG. 6 is an urgent degree determination unit processing flow that takes into account a traveling state such as a vehicle position and a vehicle speed.
FIG. 7 is a table configuration example of a service code table.
FIG. 8 is a table configuration example of a vehicle management table and an emergency level function table managed by a roadside device.
FIG. 9 is a table configuration example of a position information table held by a roadside device.
FIG. 10 is an example of an urgency function for each vehicle speed held by the roadside device.
FIG. 11 is a processing flow of an urgency management unit.
FIG. 12 is a configuration example of an emergency level management table for each vehicle ID and a transmission buffer configuration example for each vehicle ID.
FIG. 13 is a processing flow of a priority control unit according to the present invention.
FIG. 14 is a processing flow of an emergency determination unit that takes into account a vehicle position, a vehicle speed, and a road surface condition;
FIG. 15 is a table configuration example of a road surface management table and an emergency level function table managed by a roadside device.
FIG. 16 is a processing flow of a priority control unit according to the present invention.
FIG. 17 is a processing flow of an urgent degree determination unit in consideration of a vehicle position, a vehicle speed, a road surface state, and a vehicle density.
FIG. 18 is a table configuration example of a vehicle density table and a safe vehicle density table managed by a roadside device.
FIG. 19 is an overall configuration diagram of a road traffic system having a branch, which includes the priority control method according to the present invention.
FIG. 20 is a message flow example when accident information and multimedia information are mixed.
FIG. 21 is a processing flow of the priority control unit in the present invention.
FIG. 22 shows a message format of a received message and a route information table held by a roadside device.
FIG. 23 is a processing flow of an urgent degree determination unit considering a vehicle position, a vehicle speed, a road surface state, a vehicle density, and a moving route.
FIG. 24 is a table configuration example of a vehicle density table and a route management table held by a roadside device.
[Explanation of symbols]
100: Roadside communication network
101: Roadside equipment
102: Repeater
103: Internet
111: Traveling vehicle
113, 114: Vehicle
120: road
130: Falling object

Claims (8)

In a dynamic priority control method using a distributed processing system composed of a plurality of roadside devices connected to a network,
Roadside devices included in the plurality of roadside devices detect the road condition of the road where the roadside devices are installed,
The roadside device that has detected the road state sends a message including position information of the roadside device, an information type according to the road state, and a priority level determined for each message according to the information type to the network. To other roadside equipment via
The roadside device that has received the message acquires the speed of the vehicle connected to the roadside device via wireless communication ,
The roadside device that has acquired the speed determines the urgency level of the message for each vehicle based on the speed, the information type included in the message, and the position information of the other roadside device included in the message ,
The roadside device that determines the urgency level of the message for each vehicle determines the transmission order of messages for each vehicle based on the urgency level of the message for each vehicle and the priority level included in the message,
The roadside device that determines the transmission order of messages for each vehicle rearranges the transmission order of messages for each vehicle each time a new message is received,
The dynamic priority control method, wherein a roadside device that determines a message transmission order for each vehicle transmits the message to the vehicle according to the transmission order . In the dynamic priority control method according to claim 1,
The roadside device that acquired the speed determines a function determined for each speed range for each information type based on the speed and the information type included in the message, and includes the position information of the roadside device and the message. A dynamic priority control method comprising: determining an urgency level of a message for each vehicle based on a distance between position information of the other roadside devices included and the determined function . In roadside devices included in a distributed processing system composed of a plurality of roadside devices connected to a network,
Detection means for detecting the state of the road where the roadside device is installed;
A message that includes position information of the roadside device, an information type according to the road condition, and a priority level determined for each message according to the information type is transmitted to the other roadside devices via the network. Means for sending
When a message is received from another roadside device via the network, an acquisition unit that acquires the speed of the vehicle connected to the roadside device via wireless communication ;
When a message is received from another roadside device via the network, the message for each vehicle is based on the speed, the information type included in the message, and the position information of the other roadside device included in the message. First determining means for determining the urgency of
Second determination means for determining a message transmission order for each vehicle based on the urgency level of the message for each vehicle and the priority level included in the message;
Second transmission means for transmitting the message to the vehicle according to the transmission order ;
It said second determination means, the road side equipment, wherein sorting Rukoto the transmission order of the messages for each of the vehicle for each receiving a new message. In the roadside equipment according to claim 3,
Said first determining means, based on information type and contained in the speed and the message, to determine the functions that are determined for each speed range for each information type, included in the position information of the road side equipment a message The urgency level of the message for each vehicle is determined based on the distance between the position information of the other roadside device and the determined function .   In the roadside equipment according to claim 3 or 4,
  The roadside device, wherein the second determining means determines the transmission order of messages for each vehicle based on the urgency level of messages for each vehicle for each of the priority levels included in the message.   In the roadside apparatus in any one of Claim 3 to 5,
  The second transmission means includes a buffer that is assigned to each vehicle and stores a message to be transmitted to the vehicle;
  The roadside device, wherein the second transmission means stores the message in the buffer for each vehicle according to the transmission order of the message for each vehicle.   The dynamic priority control method according to claim 1 or 2,
  The dynamic priority is characterized in that the roadside device that has received the message determines the message transmission order for each vehicle based on the urgency of the message for each vehicle for each of the priority levels included in the message. Control method.   In the dynamic priority control method according to any one of claims 1, 2, and 7,
  The roadside device that has determined the message transmission order for each vehicle stores the message to be transmitted for each vehicle in a buffer allocated for each vehicle according to the message transmission order for each vehicle. Dynamic priority control method.

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