A Location- and Mobility-Aware Clustering-Based TDMA MAC Protocol for Vehicular Ad-hoc Networks

Contention-based IEEE 802.11p medium access control (MAC) protocol for vehicular ad-hoc networks (VANETs) has proven to be inefficient because it cannot ensure delivery of safety messages with a bounded delay due to and merge packet collisions, hidden terminal problem, inefficient resource utilization and unreliability in different traffic scenarios. To solve these problems, a conflict-free clustering-based MAC protocol is proposed in this paper which employs TDMA-based deterministic slot assignment to resolves access collisions and to ensure bounded delay and centralized access mechanism for efficient resource management. Mitigation of merge collisions is proposed through disjoint slot assignment and channel distribution with respect to direction of node mobility, whereas, location and mobility awareness of nodes helps in cluster formation and resolve packet conflicts due to hidden terminals. Our simulation results show that the proposed protocol performs better than IEEE 802.11p MAC and TCMAC protocols in both urban and highway traffic scenarios.