JPH0247136B2 - ROSHAKANMUSENTSUSHINSOCHINOTSUSHINSEIGYOHOHO - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a communication control method for a road-to-vehicle wireless communication device that performs wireless information communication between a roadside device installed on the road and a vehicle running on the road. .

[Conventional technology]

With the recent progress in motorization and the development of an advanced information society, a wireless system that can be commonly applied to various traffic and transportation information systems, etc. The practical application of a road-vehicle wireless communication device that identifies a vehicle and performs two-way communication of individual information closely related to the location information of the vehicle has become an important issue. In road-to-vehicle wireless communication, information is exchanged within a short time while driving within a limited wireless zone, and it is important to understand the relationship between the wireless zone and the number of lanes, the wide speed range of vehicles, and how to deal with road congestion. The reality is that there are still many issues to be solved, such as equipment costs for on-road equipment and vehicle-mounted equipment.

Conventionally, as one form of road-to-vehicle wireless communication between on-road devices and in-vehicle devices, there has been a communication method that communicates by wireless communication coupling between a road surface loop coil buried in the road and an on-vehicle coil installed in the vehicle. be.

In addition, as an example of literature describing technology for road-to-vehicle wireless communication systems,
2351, 1988, P2355, Mine Sugiyama, Yoshio Matsuo,
Hisashi Kaneko]. Figure 2 shows the "method for communicating with cars on the road using millimeter waves" described in the document.
FIG. The road-to-vehicle wireless communication is performed by setting partially overlapping wireless zones ZA to ZD for each lane A to D in multiple lanes, as shown in Figure a, and the road-to-vehicle wireless communication is performed using the communication procedure shown in Figure b. In other words, (1) the on-road device constantly sweeps and transmits the trigger code TRG to lanes A to D in a time-division manner, and (2) when a vehicle enters the wireless zone of a certain lane receives the trigger code TRG. When the code TRG is received and recognized, it transmits the access code ACC, and (3) the roadside device identifies the access code ACC received in each lane to determine the communication lane, and stops transmitting the trigger code TRG to determine the communication lane. OK code from lane
(4) When the vehicle receives the acknowledgment code ACK, it transmits an information request code (DATA1). (5) On-road equipment receives the information request code (DATA1) and performs error detection. In response, it makes a retransmission request NAK, (6) if the on-road device determines the correct request code, it sends an acknowledgment code ACK, (7) it then sends a response information code (DATA2) appropriate for the request content, and ( 8) The vehicle detects an error in the information code and NAKs a retransmission request if necessary.
(9) If you get the correct information, send the acknowledgment code.
Communication control is performed by sending an ACK and completing the communication.

[Problem that the invention seeks to solve]

However, the communication method that communicates between the road surface loop coil and the vehicle-mounted coil by wireless coupling,
Due to the structure of the road loop coil, the carrier frequency is
It is less than 300KHz, and the information transmission speed is several
The limit is about Kbit/sec, which is inappropriate for high-level information transmission including image information between road and vehicles.

On the other hand, the methods shown in Figure 1 a and b apply microwave or millimeter wave bands to road-to-vehicle wireless communication, so they can dramatically improve the information transmission speed and reduce the complexity. It has excellent advantages such as not requiring road surface burial work, but has the disadvantage that it requires relatively expensive wireless equipment as on-road communication equipment and in-vehicle equipment. The type of communication that is provided has placed significant constraints on reducing equipment costs for on-road devices, given the recent trend toward an increase in the number of road lanes. Furthermore, the communication control method of the procedure shown in FIG. If there is a problem, identification becomes impossible.

The present invention has been made in view of the above-mentioned points, and it is possible to individually identify and communicate with a plurality of vehicles traveling in one wireless zone under a wireless zone spanning multiple lanes. Communication of road-to-vehicle wireless communication equipment that reduces the number of devices installed and also simplifies and lowers the cost of on-vehicle devices by using a communication format that supplies carrier waves for transmission from on-vehicle devices from on-road devices. The objective is to provide a control method.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a road-to-vehicle wireless communication device that performs time-sharing information transmission between on-road devices and on-vehicle devices within an extremely small wireless zone. In the communication block for individually recognizing the vehicle-specific code of the vehicle, the roadside device transmits a trigger code,
After each on-vehicle device receives and recognizes the trigger code, it transmits the vehicle-specific code multiple times at randomly selected time intervals each time, and the on-road device transmits the vehicle-specific code multiple times when it receives the same vehicle-specific code more than once. By checking the vehicle-specific code of each vehicle and setting communication blocks for each vehicle's unique information from the on-road device to the on-vehicle device and from the on-board device to the on-road device, the on-road device and the on-vehicle device A communication control method was configured to communicate with.

In addition, in the communication block for individually recognizing the vehicle-specific code of one or more vehicles that have entered the wireless zone, the on-road device transmits a trigger code, and each on-vehicle device receives and recognizes the trigger code. Afterwards, the vehicle-specific code is transmitted once with a time delay selected by random numbers, and the roadside device receives the vehicle-specific code of each vehicle and performs error detection, and if an error is detected for any vehicle, By repeating the same procedure again, it is possible to recognize the exact vehicle-specific code for each car.

[Effect]

By configuring the road-to-vehicle wireless communication device as described above, each vehicle transmits a vehicle-specific code at a delay time that is independently set by a random number, so that vehicles entering the vehicle at exactly the same time and at the same speed It is also possible to reduce the probability of interference caused by duplicate transmissions for vehicles. Furthermore, by repeating this random number time difference processing multiple times,
The probability of interference is reduced in a power-law manner, and the vehicle-specific code of each vehicle can be recognized accurately and efficiently.

〔Example〕

FIG. 1 is a diagram showing the relationship between the wireless zone and the number of lanes of the road-to-vehicle wireless communication device according to the present invention, where a is a 2-lane wireless zone, and b is a 4-lane wireless zone.
The case of 2 wireless zones is shown.

In Figure 1a, the wireless zone Z (AB) that straddles lanes A and B has an effective height of 6 m, for example, the effective height of the roadside antenna based on the height of the vehicle-mounted antenna.
Assuming that the deflection angle of the directional direction with respect to the road normal is 30 degrees and the half-value angle of the directional characteristics is 45 degrees, the width is approximately 6 m and the driving direction is approximately 7 m. In the case of four lanes, the wireless zone Z (CD) straddles lanes C and D, as shown in Figure b.
will be added. When a wireless zone is set across two lanes, when there are vehicles M1 and M2 running almost parallel on both lanes, and when there is a vehicle M3 running on the same lane with a very close inter-vehicle distance during traffic congestion. may exist.

FIG. 3 is a diagram showing an example of a communication procedure of the road-to-vehicle wireless communication device when a plurality of traveling vehicles exist in one wireless zone. In the same figure,
T1 identifies the vehicle-specific code IDN, which consists of the vehicle type code, in-vehicle unit (subscriber) code, destination code, communication content (service) designation code, etc. of multiple vehicles that have entered the wireless zone, and provides route information for each vehicle. This is a communication block that allocates the content of inter-vehicle information communication, and T2 and T3 transmit individual information for each vehicle from the on-road device to the on-board device and from the on-board device to the on-road device in accordance with the order determined by block T1. It's a block. In communication block T1, first (1) a trigger code TRG is transmitted from the roadside device;
(2) When a vehicle enters a wireless zone, the corresponding trigger code is detected.
After receiving and recognizing the TRG, (3) the on-vehicle device transmits the vehicle-specific code IDN of the vehicle multiple times at randomly selected time intervals within a fraction of the period of communication block T1. do. If there are multiple vehicles entering one radio zone (M1 and M2 in the example in Figure 1), the operations in (2) and (3) above are performed for each vehicle, but each vehicle operates independently. Since random number processing is performed on the IDN, the probability that the vehicle-specific code IDN of each vehicle will be transmitted at the same time is extremely reduced. On the road machine,
(4) Receive all the vehicle-specific codes that are sent multiple times at random intervals from each vehicle, and (5) perform error control by checking multiple times for those that have received the same vehicle-specific code two or more times before entering. The vehicle unique code IDN of each vehicle is recognized, and (6) the next vehicle communication blocks T2 and T3 are set based on the communication content designation code of each vehicle. In communication block T2, (7)
The on-road device transmits the vehicle designation code DSA and the unique information DDAT from the road device to the designated vehicle. (8) The vehicle recognizes the vehicle designation code DSA and, if its own vehicle is designated, sends the on-vehicle device. Set to receive mode and receive information from roadside equipment. The information to be sent to the on-vehicle device is, for example, an information code for route guidance, or image information such as a road map, and if particularly accurate information transmission is required, such as route guidance information, (9)
The on-vehicle device detects errors in the received information, issues a retransmission request NAK if necessary, and (10) sends an acknowledgment code ACK if it determines that the information is correct. In communication block T3, (11) the on-road device transmits the vehicle designation code DSA and then switches to reception mode; (12) the on-board device recognizes the vehicle designation code DSA and, if the own vehicle is designated, sends a message from the on-board device. Unique information UDAT such as in-vehicle
The image information from the fax is sent, (13) the on-road device receives and recognizes the information from the on-board device, and sends an acknowledgment code.
After sending the ACK, it returns to the state of communication block T1.

FIG. 4 is a diagram showing another example of the communication block T1 portion of the communication procedure shown in FIG. 3 above. In communication block T1 in the same figure, (1) a trigger code TRG is transmitted from the roadside device, (2) a vehicle that has entered the wireless zone receives and recognizes the trigger code TRG;
(3) The on-vehicle device transmits the vehicle-specific code IDN of the vehicle once at a time delay that is randomly selected within, for example, 10 to 20 times the transmission time of the vehicle-specific code IDN. When there are multiple vehicles entering one wireless zone, the roadside device receives a vehicle-specific code IDN with a delay time set independently and randomly for each vehicle.
(4) Error detection is performed for each vehicle-specific code IDN on the roadside device, and if communications from multiple vehicles overlap or an error is detected for some reason, (5) repeat (1) to Repeat the steps up to (4), and when the correct vehicle-specific code IDN of each car is recognized, (6) set the next communication blocks T2 and T3 based on the communication content specification code of each car. Complete T1.

The above is an example of a case of 2 lanes and 1 radio zone, but the basic principle of the present invention can be easily extended to a case of 4 lanes and 2 radio zones as shown in Fig. 2b. Communication blocks T1 to T3 in zones Z (AB) and Z (CD) can be carried out alternately by time division of the zone terminals. In this case, if there is a vehicle that can communicate with both radio zones Z (AB) and Z (CD), such as a vehicle traveling between lanes B and C, it will not be possible to communicate with either radio zone Z (AB) or Z (CD). If the communication with the vehicle is completed, even if the roadside device in the other wireless zone recognizes the vehicle specific code IDN of the vehicle, the communication block T2 with the vehicle will be terminated.
Communication control can be performed to omit communication at T3 and communication efficiency can be increased.

FIG. 5 is a diagram showing an example of a road-to-vehicle wireless communication device that specifically implements the communication procedure of road-to-vehicle wireless communication shown in FIGS. 3 and 4. FIG. Figure a shows the system configuration of the on-road machine, and figure b shows the system configuration of the vehicle-mounted machine. The on-road device and the vehicle-mounted device are configured to drive their respective antennas 11 and 21 for both transmission and reception by circulators 12 and 22, respectively. A carrier wave oscillator 13 and an amplitude modulator 14 are installed at the transmission port of the circulator 11 of the roadside machine.
The amplitude modulator 14 is controlled by a communication control circuit 16 of the roadside device to control communication such as trigger code TRG, vehicle designation code DSA, and acknowledgment code ACK in accordance with communication blocks T1 to T3. The carrier wave is amplitude-modulated by the code or the unique information code DDAT to the on-vehicle device at the input terminal S2.
The transmitted wave from the on-vehicle device is detected by the receiver 15 of the on-road device connected to the reception port of the circulator 12, and the recognition circuit 17 of the on-road device performs error detection or collation to receive information from the recognized on-vehicle device. The signal is extracted to the terminal S1, and if transmission to the on-vehicle device is required, the communication control circuit 16 of the on-road device is controlled. In the on-vehicle unit, circulator 2
The receiver 25 of the on-vehicle device connected to the reception port 2 detects the transmitted wave from the on-road device, the recognition circuit 27 of the on-vehicle device recognizes it, and the information from the on-road device is extracted to the terminal S3. A carrier wave oscillator 23 and an amplitude modulator 24 are connected to the transmission port of the circulator, and the amplitude modulator 24 is controlled by a communication control circuit 26 of the vehicle-mounted device. The communication control circuit 26 of the on-vehicle device has a function of setting a random number delay time, and the characteristic feature of the present invention within the period of communication block T1 as detailed in FIGS. 3 and 4. Vehicle-specific code IDN is transmitted at random intervals. In communication blocks T2 and T3, a retransmission request code NAK or an acknowledgment code ACK is sent depending on the recognition result of error detection in the recognition circuit 27 of the on-vehicle device.
Alternatively, communication control is performed to transmit the unique information code DDAT from the input terminal S4 to the roadside device.

As described above in detail in the communication procedures of FIGS. 3 and 4, the basic characteristics of the communication control method of the present invention are that when multiple vehicles are present in a wireless zone spanning multiple lanes, The basic operating principle lies in the operation of the communication block T1, which accurately recognizes the vehicle-specific code of each vehicle and establishes two-way communication between the road and the vehicle. By using a delay time set independently for each vehicle using random numbers, it is possible to reduce the probability of interference due to duplicate transmissions even for vehicles that enter at exactly the same time and at the same speed. By repeating the time difference processing multiple times or performing it multiple times with error detection added, the probability of interference is reduced in a power-law manner, contributing to accurate and efficient recognition of the vehicle-specific code of each vehicle.

As a specific application example of the present invention, the vehicle-specific code is 128 bits, and the transmission speed between road and vehicle is 512 Kbit/sec.
Then, the actual transmission time for each vehicle-specific code is 0.25 msec, and if the random number delay time range is 0 to 3 msec, the probability of duplication will be reduced by about 1/10 per random number processing. will be done. Now, if the time of block T1 is 10 msec, in the case of Figure 3, the vehicle-specific code will be verified for each vehicle in the same radio zone at least 3 times and an average of 6 times. In some cases, it is possible to repeat the recognition operation three times including error detection. In addition, the time of block T1 of 10 msec is 100
This corresponds to a vehicle traveling only approximately 28 cm in km/hour. Two-way communication block T2 between road and vehicle
The contents of communication at T3 include code information such as driving information codes such as route guidance, message codes, and image information such as simple in-vehicle fax. It is sufficient for the code information to be less than 256 bits in total, and the transmission time is also
Within 1msec. For example, as image information, 4
The amount of information when transmitting an A6 size image with a resolution of 1/mm using the MH and MR methods is 45Kbit.
The transmission time of this information is approximately 88 msec, which corresponds to the time it takes for a vehicle traveling at 100 km/h to travel 2.5 m, and sufficient communication is possible even within the aforementioned extremely small wireless zone.

〔Effect of the invention〕

As explained above, according to the communication control method for a road-to-vehicle wireless communication device according to the present invention, in road-to-road communication in a wireless zone spanning multiple lanes, a plurality of vehicles exist in one wireless zone. Even in such cases, the vehicle-specific codes of each vehicle can be efficiently recognized without duplication. In addition, since the wireless zone is set across multiple lanes, the number of on-road equipment installed can be reduced in recent road conditions where the number of lanes is rapidly increasing, resulting in excellent effects such as lowering the cost of on-road equipment. .

[Brief explanation of the drawing]

FIGS. 1a and 1b are diagrams showing the relationship between the wireless zone and the number of lanes of the road-to-vehicle wireless communication device according to the present invention, and FIG. 2a is a diagram showing the relationship between the wireless zone and the number of lanes of the conventional road-to-vehicle wireless communication device. FIG. 3 is a diagram showing the communication procedure of the conventional road-to-vehicle wireless communication according to the present invention, and FIG. 4 is a diagram showing the communication procedure of the conventional road-to-vehicle wireless communication. Communication procedure block
A diagram showing another example of T1, and FIGS. 5a and 5b are diagrams respectively showing a road device and an on-vehicle device of the road-to-vehicle wireless communication device according to the present invention. In the diagram, A to D are lanes, Z (AB), Z (CD)...
Wireless zone, M1 to M3...Vehicle, TRG...Trigger code, IDN...Vehicle specific code, DSA...
...Vehicle designation code, DDAT...Unique information code from roadside device, NAK...Retransmission request code, ACK
... Understanding code, UDAT ... Unique information code from on-vehicle device, 11 ... Antenna, 12 ... Circulator, 13 ... Carrier wave oscillator, 14 ... Amplitude modulator, 15 ... Receiver, 16 ... Communication control Circuit, 17... Recognition circuit, 21... Antenna, 22
... Circulator, 23 ... Carrier wave oscillator, 2
4...Amplitude modulator, 25...Receiver, 26...Communication control circuit, 27...Recognition circuit.

Claims (1)

[Scope of Claims] 1. In a road-to-vehicle wireless communication device that performs time-sharing information transmission between a roadside device and an on-vehicle device within an extremely small wireless zone, vehicle-specific information of one or more vehicles entering the wireless zone is provided. A communication block for individually recognizing a code, wherein the on-road device transmits a trigger code, and after receiving and recognizing the trigger code, each on-vehicle device communicates with the vehicle at randomly selected time intervals. If the code is transmitted multiple times and the same vehicle-specific code is received two or more times by the on-road device, error control is performed by checking the code multiple times, and the vehicle-specific code of each vehicle is confirmed and sent from the on-road device to the in-vehicle device. and a communication control method for a road-to-vehicle wireless communication device, characterized by setting a communication block of unique information of each vehicle from an on-vehicle device to an on-road device. 2. A block for individually recognizing one or more vehicle-specific codes that have entered the wireless zone, wherein the roadside device transmits a trigger code, and each of the onboard devices receives and recognizes the trigger code, and then generates a random number. The vehicle-specific code is transmitted once with a time delay selected by the vehicle, and the roadside device receives the vehicle-specific code of each vehicle and performs error detection, and if an error is detected for any vehicle, 2. A communication control method for a road-to-vehicle wireless communication device according to claim 1, wherein the exact vehicle-specific code of each vehicle is recognized by repeating the same procedure again.