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Maximizing Network Lifetime for Connected and Non-overlapped Target Coverage in Wireless Sensor Networks
Yong-Hwan Kim and Youn-Hee Han

In wireless sensor networks, the power of sensors typically is conserved using a sensor wake-up scheduling protocol by which some sensor nodes stay active to provide sensing services, while the others sleep to conserve their energy. In particular, the CTC (Connected Target Coverage) problem has been considered as a representative energy-efficiency problem that considers two constraints: 1) the connectivity to a sink node and 2) the continuous monitoring of all targets with known locations. In this paper, we propose both a new graph model and a new sensor energy consumption model that considers these two constraints as well as the two additional constraints: 1) the removal of the redundancy caused by overlapped targets that are simultaneously monitored by multiple sensors and 2) per-target routing. Based on the proposed graph and energy consumption model, we propose a new problem called the CNTC (Connected and Non-overlapped Target Coverage) problem. In addition, we present a heuristic algorithm called the SPT (Shortest Path based on Targets)-greedy algorithm to solve the CNTC problem. Our simulation results show that our problem formulation and the proposed SPT-greedy algorithm increase the network lifetime by a reasonable extent.

Keywords: Energy efficiency, network lifetime, multiple target, sensor scheduling, and wireless sensor network.

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