Junji Inoue

Field evaluation of UHF radio propagation for an ITS safety system in an urban environment

Roadside-to-vehicle and vehicle-to-vehicle communication systems have been proposed as part of ITS development to help achieve vehicle safety and realize more secure road traffic environments. In this article we first introduce several typical applications and their radio range requirements for vehicle safety communication systems to clarify the technical point of view. Then we show some field experiment results in an urban area in Tokyo to investigate and verify the radio propagation characteristics and the quality of communications by using a wireless radio prototype system. Finally, we conclude that the current prototype system has potential to fulfill the radio range requirements of vehicle safety communications, but there are still lots of issues that need to be addressed.

Performance Evaluation of a Roadside-to-Vehicle Communication System Using Narrow Antenna Beam Switching Based on Traffic Flow Model

High reliability and low latency are crucial requirements for vehicular safety applications. We have previously proposed a media access control (MAC) protocol for a roadside-to-vehicle communication (RVC) system using narrow antenna beam switching with multiple antenna beams to increase reliability even in a shadowing region. In this paper, we describe transmission performance evaluation of an RVC system with antenna beam switching based on a traffic flow model using computer simulation. Simulation results show that our proposed technique can reduce the packet error rate (PER) of the system with a single broad antenna beam in an environment where surrounding objects reflect waves.