On achieving maximum network lifetime through optimal placement of cluster-heads in wireless sensor networks

In a wireless sensor network, the network lifetime is an important issue when the size of the network is large. In order to make the network scalable, it is divided into a number of clusters. In each cluster, a set of nodes is grouped and coordinated by a cluster-head. Due to high computations and data forwarding tasks at the cluster-heads, cluster-heads get drained out sooner. Hence, high power nodes are used as cluster-heads. Cluster-heads that are far away from the sink transmit their data packets via intermediate cluster-heads in a multi-hop fashion to the sink. Thus the cluster-heads that are near to the sink get overloaded and drained out sooner due to which the network lifetime decreases. In order to balance the lifetime of the cluster-heads, the existing works try to find either the optimum density or the optimum transmission range for the cluster-heads. The cluster-head placement algorithms should consider the fact that the node density and their transmission ranges are related parameters. In order to balance the lifetime of the cluster-head nodes and achieve the maximum network lifetime with the minimum network cost, we propose a novel Optimal Placement of Cluster-heads (OPC) algorithm. We formulate an optimization problem and find the optimum number of cluster-heads to be deployed and their optimum transmission ranges for the given network parameters. In addition, we show that our algorithm performs better than the existing algorithm, in terms of network lifetime and network cost through the simulation results. © 2007 IEEE.