Energy Efficient Coverage with Variable Sensing Radii in Wireless Sensor Networks

Wireless sensor networks (WSN) consist of spatially distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions. Generally, sensor nodes are resource-constraint in terms of size, power and bandwidth, therefore energy-efficient design becomes one of the fundamental goals in WSN. To provide reliable service in surveillance as well as energy efficiency, significant attention has recently been devoted to dynamic coverage algorithms based on sensors which are capable of adjusting its transmission and sensing range. In this paper, we propose two local sensing radii optimization schemes based on one-hop approximation of Delaunay Triangulation to minimize the energy consumption and extend the lifetime of networks. Furthermore, we prove that our approximation of Delaunay triangulation guarantees complete coverage and generates the same radii assignment as traditional Delaunay triangulation. Our ns-2 based simulation shows performance improvements in many aspects such as coverage ratio, sensing energy consumption, node failure rate, and lifetime of networks.