qCB-MAC: QoS Aware Cluster-Based MAC Protocol for VANETs

Abstract

In vehicular ad hoc networks (VANETs), high relative node mobility can result in rapid topology changes with frequent link breakage and unstable communications which causes collision and packet loss. Alternatively, cluster based communication can improve the reliability of communication. In this paper, a QoS aware cluster-based MAC (qCB-MAC) protocol for VANETs is proposed. The cluster formation mechanism is defined. New control packets are introduced and existing control packets are modified to support cluster based communications. Channel access mechanism is based on the IEEE 802.11 EDCA mechanism for different access categories (ACs) to ensure desired QoS at the MAC layer. Markov chain model based analytical analysis is presented to explore the performance of the proposed MAC protocol. Moreover, numerical results are presented to verify the performance of the proposed qCB-MAC protocol for different ACs. The proposed qCB-MAC protocol improves the system throughput and ensures desired QoS.