Topology control for wireless sensor networks with irregular and dynamic radio coverage

A critical issue in wireless sensor networks is represented by the limited availability of energy within sensor nodes. An effective approach for energy conservation is scheduling sleep intervals for extraneous nodes, while the remaining nodes stay active to provide continuous service. Most previous solutions assumed a perfect radio condition with a static, circular coverage. However, in real situations, radio signals are very dynamic and irregular in their coverage. This is especially true for wireless sensor networks, which usually employ low quality radio modules to reduce the cost. Assuming no location information is available, we approach the problem in this paper from two aspects: space and time. We present a topology control algorithm, termed OTC, for sensor networks with consideration of radio irregularity and dynamic radio coverage. It uses two-hop neighborhood information to select a subset of nodes to be active among all nodes in the neighborhood. Each node in the network selects its own set of active neighbors from among its one-hop neighbors. This set is determined such that it covers all two-hop nodes. OTC is evaluated against a well-known algorithm from the literature, namely Span through realistic simulations using TOSSIM. The results show that under dense deployment and irregular and dynamic radio coverage, our algorithm outperforms Span