Research On Virtual Energy Based Adaptive Clustering Protocol In Wireless Sensor Networks

In the research of wireless sensor networks (WSN), network topology based on cluster can not only reduce the long-distance communication, but also make integration on the data sent to the base station. So it is proven to be energy efficient. However, due to the heavy work which cluster-head has to take on, energy will be exhausted soon, thus netwrk lifetime will be affacted. Therefore, to design a energy-load balanced clustering algorithm is particularly crucial.This paper begins to study based on above problem.The main work of this paper includes:(1) Clustering protocol in wireless sensor networks is studied, including how to elect cluster-head and divide cluster size, as well as when to start cluster-head rotation, and how to select a new cluster-head after sensor nodes are deployed in the monitored area. Futhermore, the classical adaptive clustering protocol LEACH(Low-Energy Adaptive Clustering Hierarchy) and its improved protocol are analyzed.(2) A virtual energy based adaptive clustering algorithm (VEAC) is proposed. The main work of this algorithm includes. Energy driven cluster-head rotation strategy is adopted, cluster-head rotation is started when the current energy of cluster-head drops down to the threshold. The current cluster-head selects new cluster-head according to the node's position and virtual energy which can be calculated in local cluster. Therefore, the frequent network querying for energy is relaxed. The cluster-head rotation happens asynchronously in different clusters, so that reclustering is unnecessary, and the topology maintenance is localized and simplified. The results of simulation experiment show that VEAC can balance network energy-load, obviously reduce energy consumption and delay from the frequent network querying, and extend the network lifetime in homogeneous and heterogeneous networks.(3) A method of searching the optimal energy threshold is designed. Because energy threshold decides to when cluster-head rotation happens, the selection of threshold is critical. By analyzing VEAC energy consumption of data collecton and cluster reorganization, a method of searching the optimal energy threshold is proposed, this method is simple and extensible, so that it can be applied to any energy driven cluster-head rotation strategy. The results of simulation experiment show the calculated optimal energy threshold can extend more network lifetime than other threshold, and maximize the performance of VEAC.