|
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.
|