JPH0122778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inductive communication method for transmitting data between a plurality of types of roadside communication devices installed on a roadside or the like having different communication speeds, transmission procedures, etc. and a vehicle-mounted communication device.

2. Description of the Related Art Conventionally, as an example of a communication method used on the road and on a vehicle, there is a communication method shown in FIGS. 1 and 2. 1 is a roadside communication device installed on the roadside, 2 is an in-vehicle communication device installed in a vehicle, and 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. Further, 3 is an unmodulated trigger signal using only a transmission carrier, and 4 is a response signal containing in-vehicle information. In this conventional example, when a vehicle equipped with an in-vehicle communication device 2 enters the communication area where the trigger signal 3 is being transmitted, the in-vehicle communication device receives the carrier of the trigger signal 3 and informs the in-vehicle communication device that the carrier has stopped. When detected, a response signal 4 is sent out at the timing shown in FIG. 2, and the communication is terminated.

Next, a conventional example developed from the conventional example shown in FIGS. 1 and 2 will be described with reference to FIGS. 3 and 4. Reference numeral 5 indicates a roadside communication device installed on the roadside, 6 a vehicle-mounted communication device installed in a vehicle, A in FIG. This is an on-vehicle response signal transmitted from the on-vehicle communication device 6. In addition, 7 is a trigger signal containing information such as on-road vehicle type, 8 is a response signal containing in-vehicle information, and 9
is the on-road machine response signal to the response signal 8. In this conventional example, when a vehicle equipped with an in-vehicle communication device 6 enters a communication area where a trigger signal 7 is being transmitted, the trigger signal 7 is received, and the information contained in the trigger signal 7, such as the type of vehicle on the road, is received. Depending on the content, the response signal 8 is sent out at the timing shown in FIG. When the on-road communication device 5 correctly receives the response signal 8, it sends out a road-side device response signal indicating completion of communication, and ends the communication between the vehicle and the road.

However, as systems using the communication methods shown in Figs. 1 to 4 are expanded, there is a demand for coexistence of the communication methods shown in Figs. 1 to 2 with the communication methods shown in Figs. 3 to 4. It has increased. That is, since the on-vehicle communication device 2 and the on-vehicle communication device 6 coexist in the same system, the on-road communication device 1 and the on-road communication device 5
It is also necessary to mix Therefore, 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. It's coming.

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

The road communication device 1 and the road communication device 5 use the same carrier frequency.

Although the number of transmission characters, information arrangement, error control, modulation speed, etc. for transmission from the in-vehicle communication device to the on-road communication device 1 and the on-road communication device 5 may be different, the modulation method needs to be the same.

Next, one embodiment of the present invention will be described.

FIG. 5 shows an example of a system configuration according to this embodiment, and 10 is an in-vehicle communication device used in this embodiment. Next, the operation will be explained in detail.

When a vehicle equipped with an in-vehicle communication device 10 enters the communication area formed by the on-road communication device 1, the second
An unmodulated trigger signal 3 in the figure is received. When the in-vehicle communication device 10 receives the unmodulated trigger signal 3, the received data and the bit clock for the received data are not generated, so it is determined that it is the trigger signal 3 from the on-road communication device 1, and a response signal is sent at the timing shown in FIG. 4 to complete the communication.

A vehicle equipped with an in-vehicle communication device 10 is a road communication device 5.
When the vehicle enters the communication area formed by the vehicle, it receives a trigger signal 7 containing information for each type of road vehicle. Since the in-vehicle communication device 10 has a function of receiving and demodulating the trigger signal 7, it is possible to generate received data and a received bit clock and to determine the type of vehicle on the road. Therefore, when the trigger signal 7 is received, the on-vehicle response signal 8 is sent out at the timing shown in FIG. 4, and the communication is completed by waiting for the reception of the on-road device response signal.

As described above, according to the present invention, even when the communication method system shown in FIGS. 1 and 2 is mixed with the systems shown in FIGS. 3 and 4, the in-vehicle communication device 6
By introducing the in-vehicle communication device 10 instead of expanding the on-road communication device 1, the in-vehicle communication device 10 can be used even within the system of the roadside communication device 1, so the system shown in FIGS. 1 and 2 can be expanded, and complex information It has the advantage that the systems shown in FIGS. 3 and 4, which are capable of transmitting information, can be mixed together without installing multiple roadside communication devices.

[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 example, Fig. 4 is a communication timing diagram in the same method, and Fig. 5 1 is a schematic diagram of an inductive communication method in an embodiment of the present invention. 1... Road communication device, 3... Trigger signal, 4...
Response signal, 5...road communication device, 7...trigger signal, 8...response signal, 10...vehicle communication device.

Claims (1)

[Claims] 1. Has an in-vehicle communication device for inductive communication that receives an intermittent header signal transmitted from a roadside communication device and starts communication, and is capable of identifying it within the communication area of multiple types of roadside communication devices with different intermittent trigger signals. In order to carry out communication corresponding to the on-road communication device, the intermittent trigger signal is distinguished by being divided into an unmodulated trigger signal and a modulated intermittent trigger signal that allows identification of the on-road device. Inductive communication method.