BRNT: Broadcast Protocol with Road Network Topology for Urban Vehicular Ad Hoc Networks

Many multi-hop broadcast protocols have been proposed in Vehicular Ad Hoc Networks (VANETs) in order to alleviate the broadcast storm problem. In urban environments, it is important to consider the highly dynamic network topology and the effect of shadowing caused by buildings. Some traditional protocols solve these problems in the way that vehicles near intersections forward packets. However, these protocols can cause data collisions and redundant forwardings since all vehicles near intersections forwards packets. In this paper, we propose Broadcast protocol with Road Network Topology (BRNT). In order to suppress redundant forwardings, BRNT utilizes the connection relationship of adjacent road segments and classifies road segments into groups. According to the groups, BRNT dynamically changes the way of forwarding control. BRNT is able to achieve high reachability and low communication overhead in both dense and sparse networks in urban environments. Simulation results show that our protocol achieves high efficiency and reachability in an urban scenario.