JP2003208693A - Dynamic priority control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that a message according to a traffic state has not been transmittable in a conventional road traffic system. <P>SOLUTION: This dynamic priority control method, in which the road traffic system comprises vehicles traveling on roads and a plurality of roadside devices connected to a roadside communication network, comprises a step for deciding an emergency degree function on the basis of a vehicle speed managed by the reception side roadside device and a service cord imparted to the emergency information message such as accident information, by the roadside device receiving the message; a step for calculating a distance between the transmission/ reception side roadside devices from position information managed by the reception side roadside device and position information imparted to the message; a step for calculating an emergency degree showing emergency of the information by use of the decided emergency degree function and the calculated distance; and a step for transmitting the messages to the vehicle in order wherein a priority level imparted to the message and the emergency degree are high is high. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road traffic system including roadside devices installed along a road and a vehicle, in which a roadside device that has received a message includes transmission side roadside device information such as information type, The present invention relates to a priority control method for dynamically determining the urgency of a received message based on running state information managed by a receiving roadside device and determining the priority of information to be transmitted to a vehicle based on the urgency of the determined information.

[0002]

2. Description of the Related Art In a repeater that transmits a packet according to the priority of a received packet, in order to preferentially transmit the packet with the highest priority, the transmitting side that transmits the packet to the repeater has priority. "Priority flag" separately from the degree
When a packet with the priority flag set is received by the repeater, a priority control method of preferentially transmitting even packets with the same priority is disclosed in, for example, Japanese Patent Laid-Open No. 7-3363.
89).

[0003]

In the priority control method described above, the repeater sets the "priority flag" indicating that the packet has the highest priority even if the packets have the same priority. Although it was possible to transmit preferentially, since the priority flag is set on the transmitting side that transmits packets to the relay, the relay, when receiving multiple packets with the priority flag set, Packets will be transmitted in the order of acceptance. Therefore, when the priority control method is applied to the road traffic system, the roadside device preferentially transmits the most urgent information to the vehicle when a plurality of urgent information such as traffic accident information is received by the driver. There was a problem that could not be guaranteed.

[0004]

In order to solve the above problems, the dynamic priority control method according to the present invention includes (1) receiving driving assistance information such as accident information and falling object information that requires urgency. (2) Based on the transmission source position information and the transmission information such as the information type given by the transmission side node, and the traveling state such as the vehicle position and the vehicle speed managed by the reception side node,
(3) It is characterized in that the receiving side node calculates the urgency of the information and determines the priority of the information to be transmitted to the vehicle based on the calculated urgency.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described. FIG. 1 shows an ITS (Intelligent T) that distributes information to two vehicles having different speeds.
(Transport System) An overall configuration diagram of a road-to-vehicle communication system, in which multimedia information such as music and images is being delivered to a traveling vehicle from the Internet,
It is assumed that a vehicle contact accident occurs and an obstacle falls on the road. Roadside device 101-1, Roadside device 101-
2. The roadside device 101-3 is connected to the roadside communication network 100, and each roadside device can communicate with each other via the roadside communication network 100.

Further, the roadside equipment 101-1 and the roadside equipment 10
1-2, the roadside device 101-3 can mutually communicate with 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, and a vehicle traveling on the road can download multimedia information such as music or video through the roadside device and the repeater. You can The roadside communication network 100 is, for example, an optical fiber cable laid along a road.

In the example of FIG. 1, when the vehicle 113 and the vehicle 114 traveling on the road 120 have 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. The camera mounted on the roadside device captures an image of the vicinity and performs image processing to detect that a collision accident has occurred. Further, the camera mounted on the roadside device can regularly 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 another roadside device via the roadside communication network 100.

Further, the roadside device 101-which has detected a fallen object
2 transmits the falling object information to another roadside device via the roadside communication network 100. The roadside device 101-1 transmits the accident information and the falling object information to the vehicle 111 and the vehicle 112 traveling at a speed 143 of V1 km / h and a speed 144 of V2 km / h by wireless communication. Wireless communication is, for example, a short-range wireless communication DSRC (Dedicated Short) for performing short-distance and two-way communication between a roadside device and a vehicle traveling on a road.
t Range Communications).

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 a road. Vehicle 113, vehicle 1
When 14 has caused a collision accident, the roadside device 101-3 that has sensed the accident has a priority level given to each of the contents of the message and the service code indicating the position information of the roadside device 101-3 and the information type in the accident information. A message ID for identifying the message is added and the accident information message 221 is broadcast to the roadside communication network 100.

The information type is, for example, accident information, falling object information, music information, or the like. The priority level is for determining 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 the information indicating the obstacle on the road such as the accident information and the falling object information. The roadside device 101-2 that has detected the falling object 230 indicates that the roadside device 10 is included in the falling object information.
The location information of 1-2, the service code indicating the information type, the priority level assigned to each message content, and the message ID for identifying the message are assigned, and the falling object information message 222 is broadcast to the roadside communication network 100. .

The repeater 102 adds position information of the repeater 102, a service code indicating the information type, a priority level given to each message content and a message ID for identifying the message to the music information from the Internet, The information message 223 is broadcast to the roadside communication network 100.

Each roadside device that receives 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 to the vehicle from the high priority message. For example, the roadside device 101-1 that has received the accident information message 221 and the falling object information message 222 determines the priority order of the accident information message and the falling 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 having determined the transmission order of each message to each traveling vehicle transmits the falling object information 241 and the accident information 242 to the traveling vehicle 111 in the transmission order, and transmits the accident information 242 to the traveling vehicle 112. , Fallen object information 241
Send in the order of sending.

The structure 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 and various sensors. The computer 350 includes a processor 301 for performing calculations such as program execution and an OS (Operating System).
m), a ROM 302 for storing basic programs and basic data, a RAM 303 used as a processing area during program execution and a temporary storage area for data, a communication interface 311 for connecting to a 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 device are configured, and these constituent elements exchange data with each other via a bus 310. be able to.

The programs executed on the processor 301 are the communication interface 313 and the wireless communication device 330.
Can communicate with one or more vehicles via the communication interface 311 and can communicate with other roadside devices via the communication interface 311 and the roadside communication network 100. Further, the external device interface 312 and the external device 320 can be connected to each other. Information such as external video, audio, vibration, temperature, humidity, and atmospheric pressure can be collected via the. 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 the 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.

FIG. 4A shows functional blocks of a priority control method for each roadside device, and FIG. 4B shows a priority control processing flow for each roadside device. The priority control unit 400 includes a receiving unit 402,
Urgency determination unit 403, urgency management unit 404, transmission unit 40
It is composed of 5. The receiving unit 402 that has received the received message 401 determines from the service code table whether to receive the message based on the service code added to the message (step 411). The structure of the service code table is shown in FIG. The service code table 700 is a service code 7 indicating the type of service.
01 and 702 indicating the contents. For example, in the service code 1, accident information is registered. 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.

Next, the urgency determination unit 403 determines the urgency function based on the service code added to the received message and the vehicle management table and the urgency function table of the traveling vehicle connected via wireless communication. The degree is determined (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.

The vehicle management table is shown in FIG. 8 (1), and the urgency function table is shown in FIG. 8 (2). Vehicle management table 8
00 is a vehicle ID 801 for identifying a traveling vehicle connected through wireless communication and a vehicle speed 8 indicating the speed of the vehicle.
02. 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 function table 810 includes a service code 811 indicating the type of service, a vehicle speed 812 for determining the urgency function, and an urgency function 813 determined based on the vehicle speed range. For example, the urgency function F1 (D) is registered in the vehicle speed range of service code 1 of 0 to 100 km / h. D is a variable for determining the degree of urgency, and represents the distance from the road failure occurrence site such as an accident.

Next, in the urgency level management unit 404, the message ID assigned to the message is added to the urgency level management table.
The priority level and the urgency derived by the urgency discriminating unit 403 are registered, and the messages are sorted in order from the highest priority level and the highest urgency (step 413).

The urgency level management table is shown in FIG. The urgency level management table 1200 includes a transmission order 1201 indicating a message transmission order, a priority level 1202, a message ID 1203, and an urgency level 1204.
The urgency management table is managed for each vehicle. For example, the transmission order 1 of the vehicle 1 is priority level 0, message I
A message with D1 and urgency level 0.7 is registered. When a new message is registered in the urgency level management table for each vehicle, the messages are rearranged in the order of priority level and urgency level.

The transmitting unit 405 stores the messages in the transmission buffer for each vehicle ID in order from the message having the lowest transmission order 1201 in the priority management table for each priority level, and transmits the message to each vehicle (step 41).
4). FIG. 12 shows a configuration example of the transmission buffer for each vehicle ID.
It shows in (2). In the example of FIG. 12 (2), the transmission buffer for each vehicle ID is the transmission buffer 1211 of the vehicle 1 and the vehicle 2
Message is transmitted uniformly from the transmission buffer for each vehicle ID.

For example, the transmission buffer of the vehicle 1 stores a falling object information message of urgency 0.7 and the accident information message of urgency 0.5, and the transmission buffer of the vehicle 2 has an accident of urgency 0.7. The information message and the falling object information message of urgency level 0.5 are stored. The message stored in the transmission buffer for each vehicle ID is the transmission message 406 transmitted from the urgency management table, and the transmission message has a vehicle ID for identifying the vehicle transmitting the message.

FIG. 5A shows the received message format, and FIG. 5B shows the transmitted message format. The received message format 510 is a service code 511 indicating an information type, a message ID 512 for identifying a message, and 5 indicating the location information of the transmission source roadside device.
13. Priority level 51 given to each message content
4 and 515 indicating information content. The service code 511 is used by the receiving unit 402 to determine whether or not to receive the message. When the service code 511 added to the received message 510 is registered in the service code table, the message is received. To do.

The message ID 512 is for uniquely determining the message in the system, and is composed of, for example, the roadside device ID of the transmission source roadside device and the message sequence number transmitted by the roadside device. Location information 513
For example, (longitude, latitude) is given to the reception determination unit 40.
It is used when calculating the distance D to the transmission source roadside device in 3. The priority level 514 is a priority level for each content of the message given by the transmission source roadside device, and the higher the priority level, the higher the priority order of the messages to be transmitted. For example, accident information, falling object information, and music information are added to the information content 515.

The transmission message format 520 comprises a vehicle ID 521 for identifying a vehicle and information content 515. Each roadside device determines the vehicle of the message transmission destination based on the vehicle ID 521 and transmits the message.
The information content 515 is the same as the information content of the received message format 510.

FIG. 6 shows a processing flow of the urgency discriminating section. When the receiving unit 402 determines to receive the received message 401, the urgency determining unit 403 determines the urgency function from the service code, the vehicle management table, and the urgency function table added in the message (step 60).
1) From the position information given in the message and the position information of the own roadside device registered in the position information table in advance when the roadside device is installed, the distance D between the roadside device of the message transmission source is calculated ( Step 602), the urgency level E of the received message from the determined urgency level function and the calculated distance D
Is determined (step 603). FIG. 9 shows a configuration diagram of the position information table of each roadside device.

The position information table 900 includes longitude information 90.
1 and latitude information 902, the roadside device receiving the message calculates the distance D from the position information (longitude information and coordinate information of latitude information) given in the message and the coordinate information of the position information table. Further, since a computer such as a repeater is not installed on the road, NULL is registered.

For example, when the roadside device 101-1 receives the accident information message 221 transmitted from the roadside device 101-3 and the falling object information message 222 transmitted from the roadside device 101-2, wireless communication is performed from the vehicle management table. The vehicle speed V1 and the vehicle speed V2 of the connected vehicle 1 and vehicle 2 are confirmed via the following, and then the service code 1 of the accident information and the emergency function F1 of the vehicle speed V1 from the emergency function table.
(D), accident information service code 1, vehicle speed V2 urgency function F2 (D), and fallen object information service code 2
And the urgency function G1 (D) of the vehicle speed V1, the service code 2 of the falling object information, and the urgency function G2 of the vehicle speed V2.
(D) is determined, and the distance D1 (14
1) and the distance D2 (142) between the roadside device 202 and the calculated distance D1 between the roadside device 203 and the roadside device 2
The distance D2 with respect to 02 is the urgency function F1 (D) of the accident information for the determined speed V1, the urgency function G1 (D) of the falling object information for the speed V1, and the urgency function F2 (D of the accident information for the speed V2. ) And the urgency function G2 of the fallen object information
By substituting into (D), the urgency level E for the accident information and the falling object information of the speed V1 and the speed V2 is determined.

The urgency function of speed V1 is shown in FIG.
FIG. 10 (2) shows the urgency function of the speed V2. The urgency function can be calculated by using the stop distance S (V), which is the distance traveled by the vehicle between the braking stop distance and the braking reaction time, described in the Traffic Engineering Research Society "Traffic Engineering Handbook", F
(D) =-D / 10S (V) +1, G (D) =-D / 5
It is represented by S (V) +1, S (V) is 0.75 seconds for the brake reflection time of the driver, and the friction coefficient is 0.07 in consideration of safety, and S (V) = 0.208V + 0.056V
It is represented by ² , and has a distance D on the horizontal axis and an urgency level E on the vertical axis. The urgency function F1 (D) 1001 of the accident information is a function that maximizes the urgency level E at the accident occurrence point 1005, and F1 (D) =
−D / 10S (V1) +1, and the urgency function G1 (D) 1002 of the falling object information is a function that maximizes the urgency E at the falling object point 1006, and G1 (D) = − D / 5S (V
1) +1.

For example, when the roadside device 101-1 receives the accident information message 221 and the falling object information message 222, the roadside device 1 from the traveling position 1007 of the vehicle 111.
01-3 and the distances D1 and D2 to the roadside device 101-2, F1 (D1) = 0.7 and G1 (D2) = 0.5 are obtained. The traveling position of the vehicle 111 is the position of the roadside device that is connected to the vehicle 111 via wireless communication, for example, the roadside device 10
It is the installation position of 1-1.

Urgency function F2 (D) 1011 of accident information
Is a function that maximizes the urgency level E at the accident occurrence point 1015, F2 (D) = − D / 10S (V2) +1, and the urgency level function G2 (D) 1012 of the falling object information is at the falling object point 1016. The function that maximizes the urgency E is G2 (D) =
It is −D / 5S (V2) +1. For example, the roadside device 10
When 1-1 receives the accident information message 221 and the falling object information message 222, the traveling position 101 of the vehicle 111 is detected.
F2 (D1) = 0.5, G2 for the distance D1 from the road side device 101-3 and the road side device 101-2 to the distance D2
(D2) = 0.7 is 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.

FIG. 11 shows a processing flow of the urgency management section. When the urgency level determination unit 403 determines the urgency level E for the received message 401, the message ID 512, the priority level 514, and the urgency level E are registered in the urgency level management table for each vehicle registered in the vehicle management table. (Step 1101). Next, the urgency management table 120
The messages within 0 are sorted in the order of high priority level and high urgency (step 1102), and the messages with the lowest transmission order values in the urgency management table are stored in the transmission buffer for each vehicle ID (step 1103).

For example, the message ID1 of the accident information message 221 and the urgency level E = 0.7 are registered in the urgency level management table of the vehicle 1, and the message ID2 of the falling object information message 222 and the urgency level E = 0.5 are the vehicle. 1 is registered in the urgency level management table, the message ID 1 of the accident information message 221 and the urgency level E = 0.5 are registered in the urgency level management table of the vehicle 2, and the message ID 2 of the falling object information message 222 and the urgency level E = 0.7 is registered in the urgency management table of the vehicle 2. In the urgency level management table of the vehicle 1, the priority level of the accident information message and the priority level of the falling object information message are the same, and the urgency level E = 0.7> the urgency level E = 0.5. The message ID of the accident information message in the transmission order 1 of the degree management table
1 and the urgency level E = 0.7, and the transmission order 2 is rearranged so that the message ID 2 of the falling object information message and the urgency level E = 0.5 are stored.

In the urgency level management table of the vehicle 2, the priority level of the accident information message and the priority level of the falling object information message are the same, and urgency level E = 0.5 <urgency level E = 0.7.
Therefore, the transmission order 1 of the urgency level management table of the vehicle 2 includes the message ID 2 of the falling object information message and the urgency level E.
= 0.7, the transmission order 2 is rearranged so that the message ID 1 of the accident information message and the urgency level E = 0.5 are stored. Next, according to the transmission order 1201 of the urgency management table 1200, the transmission buffer 121 of the vehicle 1
1 stores an accident information message 221 with an urgency level E = 0.7 and a falling object information message 222 with an urgency level E = 0.5, and the urgency level E = 0.7 in the transmission buffer 212 of the vehicle 2.
The accident information message of the falling object information message urgency level E = 0.5 is stored. The transmission message 406 stored in the transmission buffer for each vehicle ID is uniformly transmitted to the vehicle ID 521 assigned to the transmission message.

In the ITS road-to-vehicle communication system, when multimedia information such as music or video is distributed to a traveling vehicle from the Internet, 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 received the accident information message and the falling object information message sets the urgency level of each message based on the running state such as the vehicle position and vehicle speed. Information is transmitted to each traveling vehicle in order from the information of high urgency, which is determined from the function.

As a result, when a plurality of messages having the same priority level are received, the information is not transmitted based on the order in which the messages are received, but each traveling is performed based on the urgency of the message with respect to the vehicle position and the vehicle speed. Since the order of sending messages to the vehicle is determined, even more urgent messages can be preferentially sent to later received messages, and safe and appropriate information delivery to the driver. You can

Next, the 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 is changed due to a change in weather such as a sunny day or a rainy day, the priority order of the message transmitted to the vehicle is changed. Not done. If the friction coefficient of the road surface changes depending on the road surface condition, the distance traveled from when the driver steps on the brake until the vehicle stops is different.Therefore, in order to deliver more appropriate information, a priority control method that considers the road surface condition is required. Is. In the second embodiment, a priority control method in consideration of the vehicle position, the vehicle speed, and the road surface condition will be described.

ITS for distributing information in consideration of road surface condition
The overall configuration diagram of the road-vehicle communication system is the same as the overall configuration diagram of FIG. 1, and a contact type road surface sensor described in, for example, “Furukawa Electric Bulletin No. 105 Development of Road Surface Moisture Sensor System” is embedded in the road 120. The roadside device 101-
1, the roadside device 101-2 and the roadside device 101-3 can regularly receive road surface information via the roadside communication network 100.

FIG. 13 shows a priority control processing flow of each roadside device. The functional blocks of the priority control method of each roadside device are the same as in FIG. 4 (1). The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether to receive the message based on the service code added to the message (step 131).
1).

Next, the urgency level determination unit 403 uses the service code assigned to the received message and the urgency level function table based on the vehicle management table, the road surface management table, and the urgency level function table of the traveling vehicle currently connected via wireless communication. Is determined and the urgency is determined (step 1312). The vehicle management table is the same as that shown in FIG. Figure 1 shows the road surface management table
5 (1) shows the urgency function table 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 a current road surface state.

For example, the road 12 can be cycled at regular intervals of one hour.
When the road surface information is received from the road surface sensor embedded in 0,
The corresponding road surface state is searched from the road surface information 1501 of the road surface management table 1500, and the current state 15 of the corresponding road surface information is searched.
The flag of 03 is set to 1 and the other current states are set to 0. For example, the coefficient of friction of road surface information “dry” is μ1,
The current state is set to 1, which means that the current road surface is dry. The table format of the urgency function table 1510 is the same as that in FIG.
In 513, an urgency function considering the friction coefficient is set. For example, service code 1 vehicle speed range 0 to 1
The urgency function F1 (D) (μ) is registered at 00 km / h. μ represents the friction coefficient determined from the current road surface condition.

Next, the urgency level management unit 404 registers the message ID given to the message and the urgency level derived by the urgency level determination unit 403 in the urgency level management table for each vehicle, and indicates the priority level and urgency level. The transmission order is rearranged from the highest message (step 1313).

The transmission unit 405 sequentially stores the messages in the transmission buffer for each vehicle ID in descending order of the value of the transmission order 1201 in the urgency management table for each vehicle, and transmits the messages to each vehicle (step 1314). The urgency level management table is the same as that shown in FIG. Vehicle ID
The configuration example of each transmission buffer 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 shown in FIG.
Same as (2).

FIG. 14 shows a processing flow of the urgency discriminating section. When the receiving unit 402 determines to receive the received message 401, the urgency determining unit 403 determines the urgency function for each traveling vehicle from the service code, the vehicle management table, and the urgency function table provided in the message (step 1401), the friction coefficient μ of the road surface at the time of receiving the message is determined from the road surface management table (step 1402), and the position information given in the message and the self-registered 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 level E of the received message is determined from the determined urgency level function, the road surface friction coefficient μ, and the calculated distance D (step 1404).

The position information table registered in the roadside device is the same as the position information table 900 shown in FIG. The urgency function is F (D) using, for example, the stop distance S (V) which is the distance traveled by the vehicle between the braking stop distance and the braking reaction time described in the Traffic Engineering Research Society "Traffic Engineering Handbook". = -D / 10S (V) +1, G (D) =-
It is represented by D / 5S (V) +1, and S (V) is 0.2 (S (V) = 0.2, assuming that the driver's brake reflection time is 0.75 seconds).
It is expressed by 08V + 0.014V ² / μ, and the horizontal axis is distance D,
The vertical axis has the urgency level E.

In the ITS road-vehicle communication system, when a vehicle contact accident occurs and an obstacle falls on the road while delivering multimedia information such as music or video to the traveling vehicle from the Internet, The priority control method of the roadside device that transmits information to a plurality of vehicles having different traveling speeds has been described. The roadside device that received the accident information message and the falling object information message
Based on the traveling state such as vehicle position, vehicle speed and road surface state, determine the urgency level of each message from the urgency level function of the urgency level function table registered in advance in the roadside device,
Information is transmitted to each traveling vehicle in order from high urgency information. As a result, when multiple messages with the same priority level are received, the information is not sent based on the order in which the messages are received, but each travel is performed based on the urgency of the message with respect to the vehicle position, vehicle speed, and road surface condition. Since the order of sending messages to the vehicle is determined, it is possible to preferentially send even more urgent messages to later-received messages, and the vehicle slips due to sudden braking due to the delay in information delivery. It is possible to avoid such dangers in advance.

Next, the third embodiment will be described. In the first and second embodiments, since it is assumed that the vehicle density is small, even when the vehicle density is high due to traffic congestion,
The priority of messages sent to the vehicle does not change.
If a traffic jam occurs before the vehicle arrives at the scene due to the occurrence of a road failure such as an accident, there is a new risk of a rear-end collision accident. A priority control method considering In the third embodiment, a priority control method in consideration of vehicle position, vehicle speed, road surface information and vehicle density will be described.

ITS for distributing information in consideration of vehicle density
The overall configuration diagram of the road-vehicle communication system is the same as the overall configuration diagram of FIG. 1, a contact type road surface sensor is embedded in the road 120, and the roadside device 101-1 and the roadside device 101-
2. The roadside device 101-3 measures the vehicle density from the number of communication channels in communication connection and periodically broadcasts the vehicle density information to the roadside communication network 100. Further, each roadside device can regularly receive road surface information via the roadside communication network 100.

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 that in FIG. The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether to receive the message according to the service code added to the message (step 161).
1).

Next, the urgency discriminating unit 403 is based on the service code added to the received message and the vehicle management table, road surface management table, vehicle density table and urgency function table of the traveling vehicles currently connected via wireless communication. To determine the urgency function to determine the urgency (step 161).
2). The vehicle management table is the same as that shown in FIG. The road surface management table is the same as that shown in FIG. The urgency function table is the same as in FIG. 15 (2). The vehicle density table is shown in FIG. 18 (1). Vehicle density table 1800
Is a roadside device ID 1801 that measures the vehicle density, position information 1802 of the measured roadside device, and the measured vehicle density 1
803. The vehicle density ρ is the number of vehicles traveling in the communication area per unit time,
It is represented by ρ = M / T.

M is the total number of vehicles that have communicated with roadside equipment at time T, and time T is a fixed cycle time in 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 longitude information 90 of FIG.
1, the same as the latitude information 902. Next, the urgency level management unit 404 registers the message ID given to the message and the urgency level derived by the urgency level determination unit 403 in the urgency level management table for each vehicle. Sort in order (step 16)
13).

The transmission unit 405 sequentially stores the messages in the transmission buffer for each vehicle ID in descending order of the value of the transmission order 1201 in the urgency management table for each vehicle, and transmits the messages to each vehicle (step 1614). The urgency level management table is the same as that shown in FIG. Vehicle ID
The configuration example of each transmission buffer 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 shown in FIG.
Same as (2).

FIG. 17 shows a processing flow of the urgency discriminating section. When the receiving unit 402 determines to receive the received message 401, the urgency determining unit 403 determines the urgency function for each traveling vehicle from the service code, the vehicle management table, and the urgency function table provided in the message (step 1701), the friction coefficient μ of the road surface at the time of receiving the message is determined from the road surface management table (step 1702), and the position information given in the message and the self-registered 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).

Next, the distance D is compared with the distance Di between all the roadside devices registered in the vehicle density table, and D> Di
Comparing all vehicle densities ρi and safe vehicle densities ρs,
This is performed based on the vehicle density table and the safe vehicle density table (step 1704). The vehicle density ρ i is the 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 has measured the vehicle density ρi and the roadside device that has received the message. The safe vehicle density ρs is a safe vehicle density that is premised on the fact that a sufficient vehicle interval is maintained and no vehicle accident such as a rear-end collision will occur, and it is registered as a safe vehicle density table in roadside equipment. There is.

The distance at which the vehicle distance is sufficiently maintained is, for example, 100 m or more. The safety vehicle density table is shown in FIG. 18 (2). Safety vehicle density table 1810
A value indicating the safe vehicle density is registered in, for example, 0.02 is registered. Safety vehicle density table 18
10 is registered when the roadside device is installed on the road.
All vehicle densities ρi registered in the vehicle density table
As a result of comparison with the safe vehicle density ρs (step 1705), if ρi such that ρi> ρs exists,
The minimum distance Di among the distances Di is set as the distance D used in the urgency function (step 1706). Also, all ρ
When ρi <= ρs for i, the distance D calculated at the time of receiving the message is set as the distance D used in the urgency function (step 1707). Finally, the urgency level E of the received message is determined from the determined urgency level 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.

In the ITS road-vehicle communication system, when a vehicle contact accident occurs and an obstacle falls on the road while delivering multimedia information such as music and video to the traveling vehicle from the Internet, The priority control method of the roadside device that transmits information to a plurality of vehicles having different traveling speeds has been described. The roadside device that received the accident information message and the falling object information message
The urgency of each message is determined from the urgency function of the urgency function table registered in advance on the roadside device based on the vehicle position, vehicle speed, road condition, vehicle density, etc. The information is transmitted to each traveling vehicle in order from the information. As a result, when multiple messages with the same priority level are received, information is not sent based on the order in which the messages were received, but based on the urgency of the message with respect to the vehicle position, vehicle speed, road surface condition, and vehicle density. , To determine the order of sending messages to each traveling vehicle, even for messages received later,
It is possible to preferentially transmit a message with higher urgency, and even in the case where there is congestion in the front of the vehicle, it is possible to avoid the risk of a rear-end collision or the like due to a delay in information delivery in advance. In this embodiment, each roadside device connected to the roadside communication network uses the vehicle density information calculated based on the number of vehicles in communication connection. For example, VICS (Ve
singleInformation & Commun
information system) and traffic congestion information from the road traffic information center may be used.

Next, a fourth embodiment will be described. In the first, second, and third embodiments, since straight roads are assumed, priority is given to the message transmitted to the vehicle even when the vehicle does not pass the road failure occurrence site such as an accident due to the branch of the road. The ranking does not change. If the vehicle does not pass through the fault occurrence site, the driving assistance information does not necessarily have to be treated as the most urgent information.Therefore, in order to deliver safer and more appropriate information, a priority control method that considers the travel route of the vehicle is required. is there. In the fourth embodiment, the vehicle position, the vehicle speed,
A priority control method in consideration of road surface information, vehicle density, and a moving route of the vehicle will be described.

FIG. 19 is an overall configuration diagram of an ITS road-vehicle communication system that distributes information in consideration of a moving route, and it is assumed that a vehicle collision accident occurs on a road at a branch destination.
Roadside device 101-1, roadside device 101-2, roadside device 1
01-3, the roadside device 101-4, and the roadside device 101-5 are connected to the roadside communication network 100, and each roadside device can communicate with each other via the roadside communication network 100. Also,
The repeater 102 is connected to the roadside communication network 100 and an external network 103 such as the Internet, and is connected to the vehicle 11
1 can download multimedia information such as music and images via a roadside device and a repeater. In the example of FIG. 19, when the vehicle 113 and the vehicle 114 traveling on the road 120 have a collision accident, the roadside device 101-5 which has detected the vehicle accident transmits the accident information to another roadside device via the roadside communication network 100. Send. The roadside device 101-1 that has received the accident information transmits the accident information to the V1 km by wireless communication.
It is transmitted to the vehicle 111 traveling at a speed 143 of / h. In addition, a road surface sensor for identifying the road surface state is embedded in the road 120.

FIG. 20 shows an example of a message flow when transmitting accident information to a vehicle traveling on a road. Vehicle 11
3 and the vehicle 114 cause an accident, the roadside device 101-5 that has detected the accident is the accident information and the roadside device 101-5.
Location information, a service code indicating the information type, a priority level assigned to each message content, a message ID identifying the message, and a road attribute ID identifying the attribute of the road on which the roadside device 101-5 is installed. Then, 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 in which the roadside device is installed, and 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.

Similar to the second and third embodiments, each roadside device can periodically receive road surface information from the roadside communication network 100, and can also measure measured vehicle density information about the vehicle area. Broadcast to the roadside communication network 100. Each roadside device that receives 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. Determine the priority of and send to the vehicle from the high priority message. For example, the roadside device 101-1 that has received the accident information message 221 sets the priority of the accident information message to the service code, the position information of the roadside device 101-5, the priority level of the accident information message, and the roadside device 101-1.
Is determined based on the position information managed by the vehicle, 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. The roadside device 101-1 that has determined the message transmission order notifies the traveling vehicle 111 of the accident information 24.
Send 2. The configuration of each roadside device is the same as in FIG.

FIG. 21 shows a priority control processing flow of each roadside device. The functional blocks of the priority control method of each roadside device are the same as in FIG. 4 (1). The receiving unit 402 that has received the received message 401 determines from the service code table 700 whether to receive the message based on the service code added to the message (step 210).
1).

Next, in the urgency discriminating unit 403, the service code added to the received message and the vehicle management table, road surface management table, vehicle density table, route management table, and urgency level of the traveling vehicle connected via wireless communication. The urgency function is determined based on the function table to determine the urgency (step 2102). The vehicle management table is shown in Fig. 8 (1).
Is the same as. The road surface management table is the same as that shown in FIG. The urgency function table is the same as in FIG. 15 (2). The vehicle density table is shown in FIG. 24 (1), and the route management table is shown in FIG. 24 (2). Vehicle density table 2400
Is a roadside device ID 1801 that measures the vehicle density, position information 1802 of the measured roadside device, and the measured vehicle density 1
803, road attribute I on which the measured roadside device is installed
It is composed of D2401. For example, the roadside device 101
-3 position information is (longitude 3, latitude 3), and the roadside device 10
The vehicle density measured by 1-3 is ρ3, and the roadside device 101-
The road attribute ID where 3 is installed is 2. The route management table 2410 includes a vehicle ID 2411 that is an identifier of a vehicle traveling in the own communication area, route information 2412 that indicates road attributes of a traveling route of the vehicle ID 2411, and a road attribute ID 2413 that identifies road attributes indicated in the route information. To be done. For example, the vehicle ID 1 follows a route passing through the A road in the north direction, and the destination road attribute ID is 1.

Next, the urgency level management unit 404 registers the message ID given to the message and the urgency level derived by the urgency level determination unit 403 in the urgency level management table for each vehicle, and the priority level and the urgency level are registered. The messages are sorted in order from the highest message (step 2103).

The transmission unit 405 stores the messages in the transmission buffer for each vehicle ID in order from the message with the lowest transmission order 1201 in the urgency management table for each vehicle, and transmits the message to each vehicle (step 2104). The urgency level management table is the same as that shown in FIG. Vehicle ID
The configuration example of each transmission buffer 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 shown in FIG.
Same as (2).

FIG. 22 (1) shows the received message format, and FIG. 22 (2) shows the route information table held by each roadside device. Received message format 220
0 is a service code 511 indicating the information type, a message ID 512 identifying the message, 513 indicating the position information of the transmission source roadside device, a priority level 514 assigned to each message content, a road attribute identifying the road attribute of the road. It is composed of an ID 2201 and 515 indicating information content. The service code 511, message ID 512, location information 513, priority level 514, and information content 515 are:
This is the same as the received message format in FIG. 5 (1). 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 on which the own roadside device is installed with the road attribute ID of the message transmission source, for example, an accident or the like. When the road failure occurs, it can be determined whether or not it occurred on the same road. The road attribute ID is uniquely determined for each road. If the road has the same road attribute ID and there are a plurality of branches, the position information of the transmission source roadside device with respect to the position information of the own roadside device By considering the direction vector, it is compared with the traveling route of the vehicle.

For example, when a message is transmitted to a vehicle heading northward on the A-line and the source roadside device of the received message is the A-side roadside device, the transmission-side roadside device of the receiving-side roadside device is By considering the direction vector, for example, it is possible to determine whether the message is from the north or west of the same road. The route information table 2210 includes a road attribute 2211 indicating a road attribute and a road attribute ID2 identifying a road attribute.
212. The route information table is held by all the roadside devices connected to the roadside communication network, and gives the road attribute ID 2212 when the message is transmitted to the roadside communication network.

The road attribute 2211 is the road name in which the roadside device holding the route information table is set, and is associated with the road attribute ID 2212. For example, a roadside device is installed on a road whose road attribute is Route A and whose road attribute ID is 1.

FIG. 23 shows a processing flow of the urgency discriminating section. When the receiving unit 402 determines to receive the received message 401, the urgency determination 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 processing according to the processing flow shown in FIG. 17 is performed.
If they are not the same, the vehicle density ρs of all the roadside devices registered in the vehicle density table is compared with the safe vehicle density ρs.
Is compared with the vehicle density table and the safe vehicle density table (step 2302). When ρi <= ρs for all registered ρi, the urgency level E is, for example,
It takes a constant value such as E = 0.4 (step 2303).
The safety vehicle density table is the same as that in FIG. 18 (2).
If there is ρi such that ρi> ρs, the road attribute I for ρi
D is compared with the road attribute ID given to the received message (step 2304), and when the road attribute IDs are different for all ρi, the urgency level E takes a constant value (step 2303).

Road attribute ID given to the received message
When ρi having the same road attribute ID as that of the vehicle is registered, the urgency function for each traveling vehicle registered in the vehicle management table is calculated from the service code, the vehicle management table, and the urgency function table added in the message. 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 the distance Di to all the roadside devices having the vehicle density ρi is determined from the vehicle density table position information. Then, Di which is calculated from the position information table held by the self-side device and has the smallest value among all the calculated distances Di is set as the distance D used in the urgency function (step 2307).

Finally, the determined urgency function and friction coefficient μ
The urgency level E of the received message is determined from the distance D and the distance D (step 2308). The vehicle management table is the same as in FIG. 9 (1). The road surface management table is the same as that shown in FIG. The urgency function table is the same as that in FIG. 15 (2). The position information table held by the roadside device is the same as that shown in FIG. The urgency function is the same as the urgency function shown in the second embodiment.

In the ITS road-to-vehicle communication system, when multimedia information such as music or video is being delivered to a traveling vehicle from the Internet, if a vehicle contact accident occurs on the road at the branch point, the vehicle travels on the road. The priority control method of the roadside device that transmits information to the existing vehicle has been described. The roadside device that received the accident information message
The urgency level of the message is determined from the urgency level function of the urgency level function table registered in advance on the roadside device based on the vehicle position, vehicle speed, road surface state, vehicle density, traveling state such as travel route, etc. The information is transmitted to the traveling vehicle in order from the above information.

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 messages for the vehicle position, the vehicle speed, the road surface state, the vehicle density, and the moving route are transmitted. Since the order of sending messages to the traveling vehicles is determined based on the urgency level of the vehicle, when a road failure such as an accident occurs at a point different from the traveling route of the vehicle, the information based on the traveling route of the vehicle is used. It is possible to determine whether or not an emergency is required. By handling non-urgent information as emergency information, avoid problems such as driver confusion and impatience in driving operations, and prioritize information that does not affect the driver. It is possible to avoid overhead of resources such as road-to-vehicle communication band, etc.

[0072]

According to the present invention, it is possible to provide information according to the state of the vehicle.

[Brief description of 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, falling 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 a processing flow of an urgency determination unit in consideration of traveling states such as vehicle position and 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 urgency 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 a roadside device.

FIG. 11 is a processing flow of an urgency management unit.

FIG. 12 is a configuration example of an emergency 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 urgency determination unit in consideration of vehicle position, vehicle speed, and road surface condition.

FIG. 15 is a table configuration example of a road surface management table and an urgency 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 urgency determination unit in consideration of vehicle position, vehicle speed, road surface state, and vehicle density.

FIG. 18 is a table configuration example of a vehicle density table and a safety vehicle density table managed by a roadside device.

FIG. 19 is an overall configuration diagram of a road traffic system including a priority control method according to the present invention when there is a branch.

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 is 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 urgency determination unit in consideration of vehicle position, vehicle speed, road surface state, vehicle density, and 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

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toru Sakaihara             1099 Ozenji, Aso-ku, Kawasaki City, Kanagawa Prefecture             Ceremony company Hitachi Systems Development Laboratory (72) Inventor Ken Hiraiwa             216 Totsuka Town, Totsuka Ward, Yokohama City, Kanagawa Prefecture             Ceremony Hitachi Network Platform             Home Business Division (72) Inventor Toshimichi Noaki             216 Totsuka Town, Totsuka Ward, Yokohama City, Kanagawa Prefecture             Ceremony Hitachi Network Platform             Home Business Division F-term (reference) 5H180 AA01 BB02 BB04 BB05 CC04                       CC11 DD04 EE02 EE12

Claims (4)

[Claims] 1. A dynamic priority control method using a distributed processing system including a plurality of roadside devices connected to a network, wherein a roadside device included in the plurality of roadside devices detects a traveling state of a vehicle. The detected roadside device is transmitted to the roadside device via the network based on the traveling state, and for each of a plurality of messages to be transmitted to the vehicle,
A dynamic priority control method, wherein a roadside device that determines and determines a transmission priority transmits the plurality of messages to the vehicle in an order according to the determined priority. 2. The dynamic priority control method according to claim 1, wherein the detected roadside device is associated with each of the plurality of messages, and transmission information indicating the importance of the message and the A dynamic priority control method, wherein the priority is determined based on a running state. 3. A roadside device included in a distributed processing system composed of a plurality of roadside devices connected to a network, means for detecting a running state of a vehicle having a predetermined relationship with the roadside device, and the running state. Based on the above, the roadside device has means for determining a transmission priority for each of a plurality of messages to be transmitted to the vehicle, and the determined roadside device in the order according to the determined priority, Roadside equipment comprising means for transmitting the plurality of messages to the vehicle. 4. The roadside apparatus according to claim 3, wherein the means for determining is associated with each of the plurality of messages and is based on the transmission information indicating the importance of the message and the running state. And a roadside device for determining the priority.