Analysis of Message Dissemination in Vehicular Networks

Safety-critical applications form the main motivation for intelligent transportation systems (ITSs). Studying the major concerns in such applications, i.e., delay and reliability, through mathematical analysis is extremely beneficial because it enables us to design optimized schemes. Such analysis is, however, challenging due to the dynamics of such a network. In this paper, we present a mathematical model to study delay and reliability of emergency message dissemination in vehicular networks. First, a basic model is presented using simplified assumptions about the channel. Then, we enhance the model using Rician distribution as a realistic fading model for vehicular environment. We make some interesting observations from the presented model. First, the end-to-end reliability has a fairly fast transition over time, which we formally prove in this observation. The second observation from the analytical model confirms the fact that using the vehicle density on the road is a good metric for setting the right forwarding probability in vehicles. We exploit this conclusion and propose a completely distributed forwarding strategy. Simulation studies indicate that our model does capture the delay characteristics of vehicular networks. It also affirms the effectiveness of our warning dissemination scheme in terms of delay and single-hop reliability in comparison with other well-known routing methods. We believe that this is a promising step toward accurate characterization of communication delay and reliability in vehicular networks.