Spatial Aware Geographic Forwarding for Mobile Ad Hoc Networks

Stateless greedy forwarding based on physical positions of nodes is considered to be more scalable than conventional topology-based routing. However, the stateless nature of geographic forwarding also prevents it from predicting holes in node distribution. Thus, frequent topology holes can significantly degrade the performance of geographic forwarding. So far the approaches mostly depend on excessive state maintenance at nodes to avoid forwarding failures at topology holes. In this paper, we propose and analyse spatial aware geographic forwarding (SAGF), a new approach that proactively avoids constant topology holes caused by spatial constraints while still preserving the advantage of stateless forwarding. Geographic source routes (GSR) based on intermediate locations are selected to bypass topology holes. Proactive route selection based on the spatial knowledge is a general approach, and thus can be used with any geographic forwarding algorithms. We evaluate our approach by extending greedy forwarding with spatial knowledge. Simulation results comparing with GPSR show that even simple spatial information can effectively improve the performance of geographic forwarding.