Fast-OB-VAN: A Fast Opportunistic Broadcast Protocol for VANETs

A vehicular ad hoc network (VANET) is composed by a group of communicating vehicles without the use of any infrastructure. The services provided by a VANET range from enhancing safety on an accident scene to advertisements of local services or events. Time-critical applications require packets to be broadcast with the lowest possible delay. In this paper, we propose Fast-OB-VAN, which is a broadcast opportunistic protocol compliant with the IEEE 802.11p standard. We show that by carefully setting what is sent by nodes during a transmission interval, delay may be considerably reduced. Our protocol is able to reach great achievements on delay compared with OB-VAN, which has been previously proposed in the literature. We execute an extensive campaign of simulations with the NS-3 simulator and we find that Fast-OB-VAN incurs on very low delay for broadcast packets. Moreover, we consider three additional key performance measures being the number of vehicles rebroadcasting a packet, the number of times that the protocol completes correctly, and the percentage of vehicles receiving the broadcast packet. We show that our proposed Fast-OB-VAN protocol greatly outperforms OB-VAN for most of the metrics considered.