Near-Optimal Node Clustering in Wireless sensor Networks for Environment Monitoring

Wireless sensor networks (WSNs) for environment monitoring consist of a large number of low-cost battery-powered sensors nodes, densely deployed throughout a remote or inaccessible physical space. "Energy conservation" has been identified as the key challenge in the design and operation of these networks. At the same time, clustering of sensor nodes has been widely recognized as the most promising approach in dealing with the given challenge. In our earlier work, we examine the actual energy-conservation effectiveness of node clustering in WSNs, and we prove that only clustering schemes that position their resultant clusters within the isoclusters1 of the monitored phenomenon are guaranteed to reduce the nodes\´ energy consumption and extend the network lifetime. A thorough review of the known literature on WSNs shows that the existing WSN clustering algorithms commonly do not satisfy the above requirement, i.e. they do not consider the similarity of sensed data as an important clustering criterion. Therefore, the utilization of these algorithms cannot be considered truly effective in dealing with the WSN energy conservation challenge. In this paper, we propose a novel WSN clustering algorithm - local negotiated clustering algorithm (LNCA). To our knowledge, LNCA is the first clustering algorithm that employs the similarity of nodes\´ readings as the main criterion in cluster formation. As such, LNCA is highly effective in minimizing in-network data-reporting traffic and, accordingly, in reducing the energy usage of individual sensor nodes. Our simulation results show clear performance supremacy of LNCA over two popular WSN clustering algorithms: low-energy adaptive clustering hierarchy (LEACH) and weight clustering algorithm (WCA).