Communication device between foad and vehicle, vehicle carried device and device on road

Abstract

Provided is an on-vehicle device which can deal with any of two systems (an active system and a passive system) used in a communication between road and vehicles, to provide an on-road apparatus and to provide a communication system between road and vehicles. The on-vehicle device scans the downlink of the active system, and it scans a frequency band used in the passive system. When the electric-field strength of received radio waves is a preset lower-limit value or more, the on-vehicle device is regarded as having marched into the communication area of the on-vehicle apparatus, and its frequency is stored (S110 to S130). When the stored frequency belongs to a frequency band exclusively used in the passive system, a passive communication part is immediately started, and a communication by the passive system is started. When the stored frequency belongs to a frequency band used in common by both systems, the active communication part is first started, and a communication by the active system is tried. When the content of a received signal cannot be analyzed, the passive communication part is started so as to be changed over to the communication by the passive system (S140 to S190).

Description

[0001] This case is a divisional application of the Chinese patent application with application number 01137528.0. technical field [0002] The present invention relates to a road-to-vehicle communication system that mixes two methods (passive and active) used in road-to-vehicle communication, and vehicle-mounted devices and on-road devices that can support the two methods and various applications through road-to-vehicle communication. Background technique [0003] Originally, DSRC (Dedicated Short Range Communication: Dedicated Short Range Communication) is known as a communication method for realizing automatic toll collection (ECT) of toll roads through two-way communication between an on-board device mounted on a vehicle and an on-road device installed near the road on which the vehicle travels. private short-range communication). There are two types of such communication methods, that is, a passive method in which an uplink signal from a vehicle-mounted device to a vehi...

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Problems solved by technology

[0005] Then, in the case of the former, in a vehicle equipped with only an on-board device corresponding to either method, the convenience of being able to collect a toll without stopping is not only damaged by the behavior of crossing the above-mentioned boundary, but also because the on-road device that is different from the communication method cannot communication, there is such a problem: such on-road devices have the potential to treat it as an offending vehicle

[0012] However, in the in-vehicle device that can support ETC applications and new applications, compared with only executing ETC applications, it is necessary to search for two additional frequency bands, and it takes time to specify the frequency bands to be used, that is, it is necessary to search for five more frequency bands. The problem of reducing the sufficient time for communication retry and reducing the reliability of communication

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