Direction aware cluster-based multi channel MAC protocol for vehicular ad hoc networks

This paper proposes a direction based clustering and multi-channel medium access control (DA-CMAC) protocol for Vehicular Ad Hoc Networks (VANETs). Vehicles travelling in the opposite direction may result in a short communication period. Clustering based on the direction of travel can reduce the cost of reconfiguration due to the short communication period. Each cluster consists of Cluster Head (CH), and Cluster Members (CMs). CH calculates priorities based on the eligibility function and assign each CM with a unique priority based on the number of connected neighbours, average speed deviation, and the average distance between neighbours and itself. Clusters are independently managed and locally reconfigured as vehicles travel. Moreover, the CH manages the channel access and allocates time slots to its CMs. DA-CMAC aims to reduce access and merging collisions in the channel, by grouping the time slots into two sets based on the direction of movement. Each CM is allocated with one time slot in both Control Channel Period (CCP) and Service Channel Period (SCP) to achieve fairness in channel access. Simulation results show that the proposed protocol will increase the reliability of packets and reduce the access collisions due to vehicular mobility.