A Dynamic Cooperative MAC Protocol for Vehicular Ad-hoc Networks

Vehicular Ad-hoc Network (VANET) is a promising approach to the Intelligent Transportation Systems (ITS). Several multi-channel MAC protocols have been proposed for VANET with the aim of having a reliable and bounded delay transmission for emergency messages and a throughput sensitive transmission for service messages. This paper proposes a Dynamic Cooperative MAC protocol called DC-MAC, which dynamically combines Time Division Multiple Access (TDMA) scheme with Carrier Sense Multiple Access (CSMA) scheme in order to solve synchronized collision problem. The proposed DC-MAC also exploits Multihop Forwarder (MF) for emergency message multi-hop forwarding and utilizes the resources effectively. In addition, this paper also performs an analysis for the proposed protocol using 2D-Markov chain under unsaturated traffic condition. Evaluation results of the proposed protocol in comparison with the IEEE 1609.4 are also given.