Landmark Based Circle Routing in Wireless Sensor Networks

Hole problem is a hot issue of Geographic Routing in Wireless Sensor Networks, which is caused by an area without active sensors that blocks the greedy forwarding process, thus long detour path is produced. One of the common solutions is to find a landmark and generate a routing path from the source sensor to the landmark node first, then the landmark resumes routing until to the destination to avoid long detour path. However, this approach results in a constant path prior to routing process, then the forwarding nodes in the path afford routing while other nodes are idle even if they are very close to the pre-setup routing path, thus the busy nodes run out of their energy soon and the hole is larger. In this paper, we present a novel approach, in which circles are created to guide routing thus the idle nodes near the routing path participate in the forwarding. As such, our new mechanism benefits both geographic routing and energy efficiency routing. Simulation results demonstrate that our approach significantly prolongs the lifetime of sensors over peer approaches while almost keeps the same short path as landmark based routing algorithms.