GeoDTN+Nav: Geographic DTN Routing with Navigator Prediction for Urban Vehicular Environments

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 packets by selecting relays with the best progress towards the destination or use a recovery mode in case such solutions fail. 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 This paper is an extended version of the one selected as one of the best papers in ISVCS 2008. The work is partially supported by the International Technology Alliance sponsored by the U.S. Army Research Laboratory and the U.K. Ministry of Defense under agreement number W911NF-06-3-0001, and partially supported by the state of Baden-Wurttemberg, Tschira Foundation, PTV AG and INIT AG to the research group on Traffc Telematics. P.-C. Cheng · K. C. Lee (B) · M. Gerla Computer Science Department, University of California, Los Angeles, CA 90095, USA e-mail: [email protected] P.-C. Cheng e-mail: [email protected] M. Gerla e-mail: [email protected] J. Härri Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany e-mail: [email protected] end, we propose GeoDTN+Nav, a hybrid geographic routing solution enhancing the standard greedy and recovery modes exploiting the vehicular mobility and onboard 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 store-carry-forward procedure when necessary. We propose a virtual navigation interface (VNI) to provide generalized route information to optimize such forwarding procedure. We finally evaluate the benefit of our approach first analytically and then with simulations. By using delay tolerant forwarding in sparse networks, GeoDTN+Nav greatly increases the packet delivery ratio of geographic routing protocols and provides comparable routing delay to benchmark DTN algorithms.