Design of Access Algorithm for VANET MAC Layer Based on Multi-serviced P-persistent Model

A Real-time Listening Based Self-adaptive Algorithm has been proposed in this paper. This algorithm is based on multi-serviced p-persistent model, it computes the collision/idle ratio according to four priorities of VANET to adjust the transmission probability with a self-adaptive strategy to enhance the channel efficiency. The algorithm improves system through reduces collision probability among nodes by real-time interception of channels state, calculation of collision to free ratio and sending probability. Therefore it can guarantee the equality of services with different priorities.