Making inter-flow network coding possible for unicast routing in VANETs

Designing an efficient unicast routing protocol for vehicular ad hoc networks has been a challenging issue due to the vehicle movement, limited wireless resources and lossy feature of wireless channel. We propose a protocol which utilizes inter-flow network coding to route data messages. The proposed protocol uses common backbone vehicles for different traffic flows. A reliability connected backbone is selected by considering vehicle movement dynamics and link quality between vehicles. By using inter-flow network coding at the backbone vehicles, the protocol can reduce the number of generated packets by 25% in most cases as compared to the traditional routing approach. As a result, the proposed protocol can provide a high packet delivery ratio, low overhead and low delay. We show the effectiveness of the protocol using theoretical analysis and computer simulations.