Prioritized CSMA Protocol for Roadside-to-Vehicle and Vehicle-to-Vehicle Communication Systems

This paper proposes Prioritized-CSMA (Carrier Sense Multiple Access) protocol for Japanese vehicle safety communications (VSC). To realize Japanese VSC, we have studied a protocol to carry out Roadside-to-Vehicle (R2V) and Vehicle-to-Vehicle (V2V) communications on single channel because a single 10MHz bandwidth channel on UHF band is allocated for VSC in Japan. In this case, R2V communication requires higher quality than V2V communication, so we have developed a protocol to prevent interference between R2V and V2V communications. The proposed protocol has been evaluated by field experiments and a simulation. The results confirm that the proposed protocol prevents the interference effectively and it has capability to achieve high-quality R2V communication in actual case.