On efficient replication-based routing in vehicular networks

Efficient routing in vehicular networks is one of the most challenging problems because of frequent network disruption and fast topological change. Some replication-based routing protocols such as epidemic routing have been proposed. However, these existing replication-based routing protocols cannot achieve high delivery ratio, low end-to-end delay and low delivery cost. In this paper, we design an efficient replication-based routing protocol called ERR for efficient routing in vehicular networks. ERR is a fully distributed protocol, and it has the following three desirable design objectives: first, ERR delivers the majority of the messages generated in time-to-live; second, ERR achieves low end-to-end delay; third, ERR introduces as little delivery cost as possible. To achieve these design objectives, ERR adopts an adaptive strategy for the number of copies of a message in a distributed fashion. In addition, we propose two forwarding rules for a message carrier with some copies to decide whether it should forward the message when it meets a vehicle. Based on real traces of vehicles, we have conducted real trace-driven simulations. Performance results demonstrate that ERR can increase delivery ratio, decrease end-to-end delay, and decrease delivery cost, when compared with four other alternative protocols.