A Generalized Multi-Stage P-Persistent MAC Protocol for V2V Communications

In the upcoming era of automatic driving, high reliability and low latency of vehicular communications is becoming more critical than ever before. However, the accurate delay control is still a big challenge in vehicular networks. In this paper, we propose a new generalized multistage p-persistent protocol for vehicle-to-vehicle (V2V) communications which has the explicit stochastic delay upper bound as well as the capability of flow control. The performance of the proposed protocol is analyzed based on a Markov chain model. The stochastic delay upper bound can be estimated by the geometric distribution in the basic scenario where the nodes access the channel using a slot-ALOHA like Medium Access Control (MAC) scheme. In addition, the proposed method can be extended to estimate the stochastic upper bound in the RTS/CTS scenario. Simulation results show that the proposed delay model can provide the accurate delay analysis for the safety related services and the delay upper bound for those entertainment related services in vehicular networks.