Energy-efficient target coverage in heterogeneous wireless sensor networks

This paper considers a heterogeneous wireless sensor network that consists of several resource-rich supernodes used for data relaying and a large number of energy constrained wireless sensor nodes. Sensor nodes are deployed randomly to monitor a number of targets. Since targets are redundantly covered by more sensors, we organize the sensors in set covers that are activated successively to conserve energy. In this paper we introduce the Heterogeneous Connected Set Covers (HCSC) problem that has the objective to find a maximum number of set covers such that each set cover monitors all targets and each active sensor is connected to at least one supernode. A sensor can participate in multiple set covers, but the total energy spent in all sets is constrained by the battery capacity. In this paper we show that HCSC is NP-complete and we propose two algorithms for solving this problem, an Integer Programming approach and a distributed and localized protocol. Simulation results are presented to evaluate these solutions.