RSU centric channel allocation in Vehicular Ad-hoc Networks

Safety and non safety related VANET messages have localized spatial scope and limited time relevance. A MAC protocol must ensure timely delivery of such messages with high reliability over a shared wireless medium. The Vehicles moving on the road form a fluid strait jacketed topology. In this paper, an RSU centric channel allocation protocol has been proposed to minimize channel allocation time and management overhead. An RSU divides the limited bandwidth allocated to a region into prefixed overlapping spatial clusters and the channel in each cluster is divided into time slots. A time slot is allotted to a vehicle in accordance to the priority of the request and availability of the channel. Simulation results indicate that the allocation scheme is able to deliver packets within the stipulated time with high reliability for different vehicle speeds and density for channel allocation based on three overlapping clusters. Moreover, the technique does not suffer from the hidden and exposed node problem.