Distributed Load Balancing Mechanism for Detouring Routing Holes in Sensor Networks

Well known "hole" problem is hardly avoided in wireless sensor networks because of various actual geographical environments. Existing geographic routing protocols (such as GFG [1] and GPSR [2]) use perimeter routing strategies to find a detour path around the boundary of holes when they encounter the "local minimum" during greedy forwarding. However, this solution may lead to uneven energy consumption around the holes since it consumes more energy of the boundary sensors. It becomes more serious when holes appear in most of routing paths in a large scale sensor network. In this paper, we propose a novel distributed strategy to balance the traffic load on the boundary of holes by virtually changing the sizes of these holes. The proposed mechanism dynamically controls holes to expand and shrink circularly without changing the underlying forwarding strategy. Therefore, it can be applied to most of the existing geographic routing protocols which detour around holes. Simulation results show that our new strategy can effectively balance the load around holes thus prolong the network life of sensor networks when using with GPSR.