The Multi-Class Zone ITS Communication Scheme for Real-time Communications in Intersections

This paper describes the multi-class zone ITS communication scheme considering real-time and short periodical communications for vehicle safety in intersections. In our proposed scheme, an area near an intersection is categorized into the nearest area and the quasi-nearest area. Vehicles communicate with a base station every 20 ms in the nearest area. In the quasi-nearest area, vehicles communicate with the base station for safety, and also make reservations for the communication for the nearest area. For performance evaluation, a microscopic traffic flow simulator is constructed and simulation of the scheme is carried out. We assume large intersections in Japan. First, simulation results show the required frequency bandwidth for realization of the scheme. The results show that the required frequency for vehicle safety in intersections is 12.9 MHz. Second, the performance evaluation considering shadowing effects is carried out. Though the frequency bandwidth is expanded, some vehicles can not communicate periodically because of shadowing effects. Using only half of the required frequency bandwidth causes lack of the number of communication slots. As the result, vehicles which can not communicate every 20 ms come into existence.