عنوان مقاله [English]
The purpose of this paper is to reduce energy consumption and improve lifetime of a wireless sensor network (WSN) which is capable of covering all targets. Targets are special points of sensing field with determined locations that need to be constantly monitored. To this end, sensor nodes are categorized into number of groups called cover sets using an optimization approach. Each set alone, is able to cover all the targets. The operation of the network is divided into rounds with the same lengths. In the beginning of each round, one cover set is selected and will perform the monitoring task for current round while other nodes in other sets, are in sleep mode. Clustering and routing decisions of the network is calculated via a Mixed-Integer Linear Programming (MILP) model. Simulation results show that our proposed method not only fulfills the coverage requirements of the network, but also improves the network lifetime. Also, the impact of altering the number of cover sets reveals a tradeoff between the number of sets and the sensing radius adopted by sensors. Moreover, the proposed method outperforms similar algorithms in terms of network lifetime.