An Optimal Broadcast of Warning Messages in Vehicular Ad Hoc Networks

In vehicular ad hoc networks, multi-hop broadcast is a key technique to disseminate warning messages for safety applications. Due to the vehicle mobility and lossy wireless channel, highly reliable, scalable and fast multi-hop broadcast protocol is very challenging to design. A number of solutions have been proposed in the past few years. However, the tradeoff between reliability and efficiency in such solutions needs to be carefully considered. The scope of this paper is to present an optimal protocol for the broadcast of safety messages in VANETs. Optimality, in terms of delay and transmission count, is achieved using a broadcast strategy that exploits opposite vehicles. To carry out reliable and efficient broadcast coordination, intelligent periodic rebroadcasts, which effectively adapt our protocol to sparse and dense networks, are proposed. Simulations are conducted and results are presented to show that it has a better performance over existing competing protocols. Keywords-Optimal broadcast; safety applications; VANETs;