Visibility-Graph-Based Shortest-Path Geographic Routing in Sensor Networks

We study the problem of shortest-path geographic routing in a static sensor network. Existing algorithms often make routing decisions based on node information in local neighborhoods. However, it is shown by Kuhn et al. that such a design constraint results in a highly undesirable lower bound for routing performance: if a best route has length c, then in the worst case a route produced by any localized algorithm has length Omega(c²), which can be arbitrarily worse than the optimal. We present VIGOR, a visibility-graph-based routing protocol that produces routes of length Theta(c). Our design is based on the construction of a much reduced visibility graph, which guides nodes to find near-optimal paths. The per-node protocol overheads in terms of state information and message transmission depend only on the complexity of the field´s large topological features, rather than on the network size. Simulation results show that our protocol dramatically outperforms localized protocols such as GPSR and GOAFR+ in both average and worst cases, with reasonable extra overheads.