A Clustering-Based Adaptive Multiple Access Protocol for Vehicular Ad Hoc Networks

To maintain a reliable, stable and efficient clustering architecture for vehicle ad hoc networks, we propose a stable weighted clustering (SWC) algorithm, which introduces a novel cluster mobility factor associated with the traffic loads to achieve better cluster stability. Meanwhile, in order to improve the channel utilization, we propose an adaptive multiple access (AMA) protocol. It adopts different access mechanism, i.e., random access, on-demand access, group time-slot reservation and polling channel access, for different traffic load and the number of accessed vehicle users. We use the network simulation tool NS2 and SUMO to obtain the relevant performance results. The simulation results show that SWC algorithm outperforms traditional weighted clustering algorithm due to taking the road environment into account in the cluster mobility factor, AMA protocol outperforms CSMA protocol due to accessing the network flexibly according to the traffic levels, and the combination of SWC and AMA, i.e., AMAC protocol, has better performance than AMA protocol because of the integration of advantages of these two protocols.