Energy and deployment aware sensing for wireless sensor networks

Sensor nodes having limited and unreplenishable power resources. However the density of deployment is very high leading to a lot of redundancy. A lot of resources are wasted without the design of efficient algorithms. One of the approaches to saving energy is to turn off redundant nodes. In this paper, we propose an optimization problem which minimizes the total energy consumption by turning off redundant nodes while satisfying the condition that every point in the target area is covered. Then we prove that the optimization problem is NP-complete. We further propose three distributed greedy algorithms which utilize local energy and deployment information to turn off redundant nodes while still covering the whole sensing area. We test the effectiveness of our protocols by comparing our schemes with a random scheme proposed in earlier work [T. Yan et al, 2003]. Our schemes achieve significant gains in energy savings and also improve the half-life of the network. Inspite of the extra overhead associated with our schemes our proposed protocols have significantly better performance.