Priority Based Inter-Vehicle Communication in Vehicular Ad-Hoc Networks using IEEE 802.11e

In this paper, we study the use of IEEE 802.11e for priority based safety messaging for inter-vehicle communications (IVC) in vehicular ad-hoc networks (VANET). The message priorities, which are assigned based on message urgency, are associated with different quality of service in terms of average delay and normalized throughput. We investigate the use of IEEE 802.11e to provide priority based service differentiation. To increase the communication reliability we also apply a repetitive transmission mechanism that provides proportional reliability differentiation for each prioritized message. We evaluate the performance of our proposed protocol using OPNET Modeler, in terms of average delay and normalized throughput as a function of the number of repetitions, number of vehicles, bit error rates, data rates, percentage of priority 1 vehicles and packet size. The results show that using proper parameter setting for IEEE 802.11e and appropriate number of repetitions per priority class will result in an efficient solution for IVC that supports different priority safety messaging.