A Contention-Based Routing Protocol for Vehicular Ad Hoc Networks in City Environments

Routing is crucial to the success of VANET applications, which is complicated by the fact that VANETs are highly mobile, and sometimes partitioned. This paper proposes a contention based routing protocol for VANETs in city environments. Different from the position based routing, this protocol does not require the node to maintain its neighborspsila locations. Junctions through which a packet must pass to reach its destination are chosen dynamically and one by one. Once the next junction is determined, a contention-based forwarding is used to forward packet to the selected junction where the next hop is selected through a distributed contention process by all neighbors receiving the packet. When the next hop does not exist due to the partitioned network, a specific timeout mechanism is proposed to forward the packet in the future. Furthermore, this protocol can handle the scenario where the destination node is moving. Simulation result shows that it achieves significant performance improvement compared with position based approaches.