Performance evaluation of IEEE 802.11p MAC protocol in VANETs safety applications

VANETs are becoming more and more popular as a way to increase the traffic safety and comfort. The IEEE 802.11p standard, especially the 802.11p MAC protocol, has attracted much attention as part of the WAVE protocol in VANETs. Safety applications, as one of the main categories of applications in VANETs, is very challenging for the design of a MAC protocol due to their low latency and high reliability requirements. The CCH interval is also a key parameter for the 802.11p MAC protocol since it can affect the performance of safety message delivery significantly. In this paper, a simulation based evaluation is proposed to evaluate the performance of the 802.11p MAC protocol with various vehicle densities and CCH interval settings. The evaluation results indicate that the 802.11p MAC protocol can be improved via extending the CCH interval. However, the reliability is still very challenging due to high collision rates.