Enhanced Selective Forwarding Scheme for Alert Message Propagation in VANETs

Recently vehicular safety applications have been introduced to improve traffic safety and efficiency. These applications are classified into two types: safety-oriented and non-safety applications. In this classification, safety-oriented applications are usually provided by means of vehicular multi-hop broadcasting in order to support reliable and fast alert message propagation to all surrounding vehicles when an emergency event occurs on a road. In VANETs, broadcast-based packet forwarding is usually preferred in order to propagate urgent traffic-related information to all reachable nodes within a certain dangerous region. However, this approach may cause broadcast storm problem, which can lead to serious contention in transmission between adjacent nodes. With this motivation, in this paper, we propose an alert message propagation scheme based on selective forwarding that aims at i) minimizing the number of rebroadcasting nodes, and ii) guaranteeing reliable and fast alert message delivery to all reachable nodes. The proposed scheme is evaluated using two types of highway scenarios. The simulation results show that the proposed scheme performs better than existing broadcast schemes in terms of message delivery latency, message delivery ratio, and message rebroadcasting ratio.