A probabilistic routing by using multi-hop retransmission forecast with packet collision-aware constraints in vehicular networks

In this paper, we introduce a novel reliable and low-collision packet-forwarding scheme for vehicular ad hoc networks, based on a probabilistic rebroadcasting. Our proposed scheme, called Collision-Aware REliable FORwarding (CAREFOR), works in a distributed fashion where each vehicle receiving a packet, rebroadcasts it based on a predefined probability. This probability is manipulated by different physical factors derived from the vehicular environment, including density of the vehicles in the vicinity, distance between transmitting and receiving vehicles, and finally, transmission range of the next-hop. All these factors are combined into one probability that enables each vehicle to evaluate whether there is another vehicle that ought to be receiving this message and could be feasible if the message is rebroadcasted. The success of rebroadcast is determined based on allowing the message to travel the furthest possible distance with the least amount of packet rebroadcast collision.CAREFOR is different from other existing techniques as it accounts for the effect of the next-hop transmission in the rebroadcast decision. Simulation results show the effectiveness of our approach in terms of limited number of rebroadcasts needed with low collision probability as compared to existing techniques. Two and three-hops message retransmissions are also considered.