Improvement Of The Cluster Head Selection In Wireless Sensor Network Clustering Protocol Leach Protocol

Wireless sensor network can be applied to many areas such as military affairs, commerce, medical care, environmental monitoring, and it has become a new research focus on computer and communication fields.Wireless sensor network is a kind of self-organized network which composes many small nodes connected by wireless communication technology. Because sensor nodes are usually small devices with limited on-board energy supply and it is impossible to replace the batteries for them, the network lifetime has become one of the key performance indexes of wireless sensor network. So far clustering is considered an efficient way to perform energy management and to extend the network lifetime.This dissertation analyzes the advantages and disadvantages of the existing routing protocols. The classical LEACH(Low Energy Adaptive Clustering Hierarchy) protocol of hierachical sensor networks is analyzed and discussed in detail. Cluster formation algorithm is the main content of LEACH protocol and cluster-head selection is the key technique of cluster formation algorithm. The cluster-head selection in LEACH routing protocol can't guarantee the proper position of cluster-heads and doesn't account for energy of nodes left. So it would lead to the energy of cluster-heads exhausted and reduce the network lifetime. Based on the shortcomings of cluster-head selection algorithm, new improved routing protocols are given:1. I adjust the LEACH routing protocol, and then name the advanced routing protocol LEACH NEW, in which I adjust cluster-head selection algorithm due to the coverage. In the new protocol, the nodes with different coverage would be treated differently. The nodes with low coverage are charged with more communication relay work, in order to increase the network lifetime as much as possible, as well as insuring the network overlaying percentage.2. I adjust the LEACH routing protocol, and then name the advanced routing protocol LEACH-M, in which I consider the distances between cluster-heads. The new protocol, in which the distances between cluster-heads are limited and the energy of nodes are considered, could reduce the consumption of energy and extend the network lifetime.Simulations on NS2 platform show that all of the improved routing protocols outperform LEACH in term of network lifetime.