Reliability and Real-Time Analysis of Safety-Related Messages in VANET

In vehicular ad hoc network (VANET), IEEE 802.11p protocol has been adopted for transmitting the information through vehicle-to-vehicle and vehicle-to-infrastructure communication. Due to the dynamic topology and the real-time constraints, broadcast is an effective approach to deliver the safety-related messages. The reliability and real-time analysis of the safety-related messages can make better decisions on the adaptation and improvement of the standard. In this paper, a Markov chain model has been proposed to investigate the broadcast performance of IEEE 802.11p with two access categories (ACs). Based on the proposed model, closed form expressions, such as packet delivery ratio (PDR) and total delivery delay are derived, taking different ACs, hidden terminal problem and frozen mechanism into account. The obtained numerical results can be used to determine a good tradeoff between the implementation and the network parameters and also help to analyze the capabilities and limitations of the standard.