Opportunistic vehicular ferrying for energy efficient wireless mesh networks

Vehicular ad-hoc networks will soon support a wide variety of inter-vehicle and vehicle-to-roadside applications. In many cases these networks will also co-exist with battery operated networks such as those deployed for sensor and mesh networked applications. In these latter types of networks, mesh node energy efficiency is often of paramount importance. This paper proposes improvements in mesh network energy efficiency by opportunistically ferrying delay tolerant traffic through co-existent vehicular networks. This is accomplished by dynamically routing traffic through vehicular paths when this forwarding is compatible with traffic flow quality-of-service constraints. The proposed mechanism is referred to as opportunistic vehicle assisted forwarding (OVAF). A model is formulated which provides an optimum routing bound under different objectives using hybrid multi-hop mesh routing and vehicular packet forwarding. A heuristic is then presented which can be used in practical networks which use OVAF. Simulation results show large improvements in network performance when this is used compared to conventional single-network multi-hop forwarding.