JPS5923639A - Inductive communicating method - Google Patents

Abstract

PURPOSE:To perform inductive communication efficiently, by adjusting a reception and modulation speed to the maximum modulation speed of car transmitter for communication, discriminating the kind of the transmitter whose signal is received from the code constitution of its received data, and performing communication in conformity with the on-vehicle transmitter. CONSTITUTION:When a car transmitter 2 enters the communication area of an on-road transmitter 10 which sends a trigger signal, the transmitter 2 processes a trigger signal containing only a carrier and a trigger signal containing on-road information in the same way to sent an answer signal. Then, the transmitter 10 once receiving the answer signal from the transmitter 2 modulates data at a modulation speed conforming to the maximum modulation speed among the speeds of plural car transmitters used in this system. Consequently, when the answer signal is received from the transmitter 2, the received data is all received and demodulated in two-bit pair form. The transmitter 10, on the other hand, regards this answer signal as a signal from the transmitter 2 and comparesses the data from two bits to one bit to detect an information string and an error, completing the communication.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to multiple types of in-vehicle communication devices installed on roadsides and the like and in vehicles such as buses, and an inductive communication method for transmitting data by inductive communication.

2. Description of the Related Art Conventionally, as an example of a communication method used between the road and the vehicle, there are methods shown in FIGS. 1 and 2. In Fig. 1, 1 is a roadside communication device installed on the roadside, 2 is an on-vehicle communication device installed in a vehicle, and in Fig. 2, A is a roadside communication device 1.
B is an on-vehicle response signal transmitted from the in-vehicle communication device 2 in response to the on-road transmission signal. In addition, 3 is an unmodulated trigger signal using only the transmission carrier,
4 is a response signal containing in-vehicle information. In this conventional example, 3
When a vehicle equipped with an in-vehicle communication device 2 enters the communication area where the trigger signal of The response signal 4 is sent out at the timing shown in FIG. 2, and the communication is ended.

Next, an example of a communication method used as a developed version of the conventional example shown in FIGS. 1 and 2 will be described with reference to FIGS. 3 and 4. 5 is a roadside communication device installed on the roadside, 6 is an in-vehicle communication device installed in a vehicle, and in FIG. 4, A is a roadside communication device 5.
B is an on-vehicle response signal transmitted from the on-vehicle communication device 6 in response to the on-road device transmission signal.

7 is a trigger signal containing information such as road model type, 8 is a response signal containing in-vehicle information, and 9 is a road-F machine response signal to the response signal 8. In this conventional example, when a vehicle equipped with an in-vehicle communication device 6 enters the communication area where the trigger signal No. 7 is being transmitted, the trigger signal No. 7 is received, and information such as the type of road vehicle included in the trigger signal is transmitted. Depending on the content, 8 response signals are sent out at the timing shown in FIG. Road communication device 6
When the response signal 8 is correctly received, a roadside device response signal indicating completion of communication is sent out, and communication between the vehicle and the road is terminated.

However, as systems using the conventional communication methods shown in FIGS. 1 to 4 have expanded,
There is an increasing demand for a combination of the communication method shown in FIG. 3 and the communication methods shown in FIGS. 3 and 4. That is, since the on-vehicle communication device 2 and the serial communication device 6 coexist within the same system, it is necessary to also coexist the roadside communication device 1 and the roadside communication device 5. For this reason,
Even if the point where you want to communicate with the on-board communication device 2 and the on-board communication device 6 is the same location, it is necessary to install two types of on-road communication devices, which poses problems in terms of economy and construction. .

The present invention provides an inductive communication method that allows one type of on-road communication device to communicate with a plurality of vehicle-mounted communication devices that meet the following conditions.

■ The in-vehicle communication device 2 and the in-vehicle communication device 6 use the same carrier frequency.

■ The number of transmission characters, information arrangement,
Although the error control and the like may be different, the modulation method must be the same, and even if the modulation speed is different, it must be an integral multiple.

Next, one embodiment of the present invention will be described with reference to FIGS. 6 and 7.

FIG. 6 shows an example of the system configuration according to this embodiment, FIG. 6 shows the communication timing between the on-vehicle communication device 2 and the on-road communication device 10, and FIG. 7 shows the communication timing between the on-vehicle communication device 6 and the on-road communication device 10. 1o is a road communication device used in this implementation.

The road communication device 1o sends out a trigger signal 7 as a trigger signal and makes noise. When a vehicle equipped with an in-vehicle communication device 2 enters this communication area, the in-vehicle communication device 2 does not distinguish between the carrier-only trigger signal 3 and the trigger signal 7 containing road information, so the same processing as the carrier-only process is performed. and response signal 4
Send out.

When the roadside communication device 10 receives a response signal from the vehicle-mounted communication device, it demodulates the data at a modulation rate that matches the maximum modulation rate of the plurality of vehicle-mounted communication devices used in this system.

In other words, the modulation speed of the in-vehicle communication device 2 is set to 240o baud (B
aud) If the modulation rate of the on-vehicle communication device 6 is 4800 baud, the on-road communication device 1o performs demodulation at 4800 baud. As a result, when a response signal from the vehicle-mounted communication device 2 is received, all received data is received and demodulated in a 2-bit bare format.

When the on-road communication device 1o receives and demodulates the signal in which all received data is 2-bit bare, this response signal is assumed to be from the vehicle-mounted communication device 2, compresses 2 bits into 1 bit, and arranges the information and eliminates errors. and complete the communication. Note that if the on-board communication device 2 and the on-board communication device 6 have the same modulation speed,
Naturally, identification is possible using internal data (system number, etc.), so there is no particular problem.

Next, when a vehicle equipped with the on-vehicle communication device 2 enters the communication area where the trigger signal 7 is being sent, communication is completed according to the communication procedure shown in FIG. 7 (same as in FIG. 4).

As described above, according to the present invention, it is possible to communicate with in-vehicle communication devices of different types of transmission speeds using one roadside communication device, so there is no need to install multiple roadside communication devices. It has great advantages in terms of economy and ease of construction.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional inductive communication method, FIG. 2 is a communication timing diagram in the same method, FIG. 3 is a schematic diagram of another conventional inductive communication method, and FIG. 4 is a communication timing diagram in the same method.
FIG. 6 is a schematic diagram of an inductive communication method according to an embodiment of the present invention, and FIGS. 6 and 7 are communication timing diagrams of the same method. 2...--In-vehicle communication device, 3...--Trigger signal,
4-...Response signal, 6-...In-vehicle communication device, 7...
...Trigger signal, 8..Response signal, 9..Roadside device response signal, 10..Roadside communication device.

Claims (1)

[Claims] There are multiple types of in-vehicle communication devices and on-road communication devices that use the same carrier frequency and have different modulation speeds by integral multiples, and the reception demodulation speed is adjusted to the maximum modulation speed of the in-vehicle communication device that communicates. An inductive communication method characterized in that the type of a received vehicle-mounted communication device is determined from the code structure of data, and communication is performed in accordance with the vehicle-mounted communication device.