GeoDTN+Nav: A Hybrid Geographic and DTN Routing with Navigation Assistance in Urban Vehicular Networks

Position-based routing has proven to be well suited for highly dynamic environment such as Vehicular Ad Hoc Networks (VANET) due to its simplicity. Greedy Perimeter Stateless Routing (GPSR) and Greedy Perimeter Coordinator Routing (GPCR) both use greedy algorithms to forward packet and try to find a route by the right-hand rule in perimeter mode when it encounters a local maximum. These protocols could forward packets efficiently given that the underlying network is fully connected. However, the dynamic nature of vehicular network, such as vehicle density, traffic pattern, and radio obstacles could create unconnected networks partitions. To this end, we propose a hybrid geographic routing solution GeoDTN+Nav that exploits the vehicular mobility and on-board vehicular navigation systems to efficiently deliver packets even in partitioned networks. GeoDTN+Nav outperforms standard geographic routing protocols such as GPSR and GPCR because it is able to estimate network partitions and then improves partitions reachability by using a storecarry-forward procedure when necessary. We propose a virtual navigation interface (VNI) to provide generalized route information for the delay tolerant forwarding. We finally evaluate the benefit of our approach first analytically and then with simulations. By using delay tolerant forwarding, GeoDTN+Nav greatly increases the packet delivery ratio in a sparse network.