Analysis of Message Delivery Delay in Vehicular Networks

Improving the safety of roads and passengers is the main goal of intelligent transportation systems (ITS). However, reducing traffic and car accidents can only be achieved by disseminating safety information in a timely manner with high reliability. Although mathematical modeling of this process is extremely beneficial, analyzing the information dissemination is considerably complex due to the dynamics of vehicles and varying travel behavior. We present a mathematical model to study the delay-reliability features in a vehicular network. The proposed model not only captures both physical and medium access control (MAC) layers' characteristics of this network but addresses the partitioning problem, i.e., the tendency of cars to form disconnected islands, as well. To the best of the authors' knowledge, this is the first delay model that does all of these, and it can be used to understand the message propagation behavior in vehicular networks. The common assumption in the literature is that the intervehicle distances (IVDs) both inside the island and between islands have the same exponential distribution. We show that this assumption is flawed, and subsequently, a new and more accurate model is presented. Simulation studies validate the accuracy and effectiveness of the proposed model for both highway and urban scenarios.