Cool: On Coverage with Solar-Powered Sensors

In this paper, we study the dynamic node activation schedule for the utility based coverage problem in solar-powered wireless sensor networks. We assume that the utility achieved by a WSN for coverage service is a sub modular function over the set of sensors that will provide the service. We first present an integer programming formulation with sub modular objective functions. We then present an efficient simple greedy hill-climbing algorithm such that the achieved average utility of the computed schedule is at least 1/2 times that achieved by the optimal schedule. To the best of our knowledge, this is the first polynomial time algorithm that can ensure a good constant approximation of the achieved utility for multi-target coverage problem. We conduct extensive evaluations to study the performances of our proposed aggregation scheduling algorithm on real testbed. Our evaluation results corroborate our theoretical analysis.