A performance evaluation of warning message dissemination in 802.11p based VANETs

In this paper, we present a performance evaluation study analyzing the behavior of a generic warning message dissemination (WMD) mechanism in a 802.11p based VANET. In our WMD method, warning-mode vehicles notify nearby vehicles in order to improve traffic safety and to control traffic congestion. Our evaluation uses 2k factorial methodology to determine the most representative factors that affect WMD performance. We performed simulations to evaluate the impact of different characterizing factors. Performance metrics evaluated are: (a) the time required to propagate the warning messages, (b) the number of blind nodes (i.e., nodes that do not receive these packets), and (c) the number of packets received per node. Simulation results show that the propagation delay is lower when node density increases, and that the percentage of blind nodes highly depends on this factor too. Factors that affect the number of packets received include downtown size, the probability of being in downtown, and the number of nodes. Lastly, we discovered that the size of packets sent does not significantly impact WMD performance.