Virtual Circle Based Geometric Modeling of Holes for Geographic Routing

Void areas (holes) are hardly avoided in wireless sensor networks because of various actual geographical environments, e.g., puddles, buildings or obstacles, or uneven energy consumption. To bypass holes, most existing geographic routing protocols tend to route data packets along the boundaries of holes by perimeter routing scheme. Such a scheme depletes the energy of nodes on the boundary of holes faster than others and is likely to result in earlier deaths, thus enlarging the hole sizes, a phenomenon we call the hole diffusion problem. Routing along the hole boundary may also lead to increased collisions especially if multiple data streams try to bypass a hole simultaneously. In this paper, we propose virtual circle based geometric modeling of holes for geographic routing to address these problems in wireless sensor networks. Our proposed algorithm avoids routing on the hole perimeter by selecting appropriate intermediate anchor nodes (close to the hole boundary) and routing via this anchor node. We show by simulation that our proposed algorithm provides significant savings in energy consumption, shorter routing delays, higher packet delivery ratio, all with comparable control overhead as compared with state-of-the-art techniques.