Analysis of Safety Messages Delivery in Vehicular Networks With Interconnected Roadside Units

This paper analyzes the delivery delay of safety messages in vehicular networks with interconnected roadside units (RSUs) and gives a suggestion which forward mechanism should we adopt to obtain a smaller delay. In this paper, we develop a mathematical model in a sparse bidirectional highway scenario with interconnected RSUs, and analyze the safety messages delivery delay with general “store-carry-forward”mechanism and decelerating “store-carry-forward”mechanism, respectively. By comparing the average messages delivery delay with two mechanisms, we can determine whether the vehicles in opposite direction need to perform the decelerating “store-carry-forward”mechanism to obtain the smaller delivery delay, when the accident occurs in some location between two neighbor RSUs. In addition, we analyze the impact of different parameters on the average delivery delay with two mechanisms and the critical location. The critical location is the location where the accident occurs, the average messages delivery delays with two mechanisms are the same. At the critical location, the average messages delivery delay is the maximum value, given the inter-RSU distance. Thus, it can be the guidance for the RSU deployment as well, considering the time-constraint safety messages. Finally, the simulation results verify that our analytical results are correct and accurate.