The Research And Improvement Of LEACH Protocol

Wireless Sensor Networks (WSN) are spawned as Micro-Electro-Mechanism System (MEMS), System on Chip (SOC), wireless communication and low-power embedded technology are in rapid development. It brings information revolution with its low power consumption, low cost, distributed and self-organizing, and it has wide application prospects. Therefore, the study on design or optimization of more efficient network protocols for the WSN to extend the network lifetime and improve its performance (such as packet delivery rate of success, energy efficiency, etc.) is very necessary.LEACH (Low Energy Adaptive Clustering Hierarchy) routing protocol is made a detailed analysis in this thesis. It is a classical hierarchical clustering WSN routing protocol; the protocol specific algorithm is divided into two phases:the cluster construction phase and the stable data transmission phase. At the first phase, the selection algorithm of cluster head only considers the fairness of a node as cluster head from the probability viewpoint, without considering the important factors such as:the nodes energy, cluster head marginalized, the data transmission distance of node to cluster head in the cluster. So in the view of node energy question, this thesis has combined the energy proportion in the original protocol's threshold value. In the view of question from cluster head marginalized, this thesis has combined the node to the central distance in the original protocol's threshold value. Thus it reduces the cluster head's marginalization and increases the bunch of cluster head's coverage, and so this thesis present the LEACH-ED (Low Energy Adaptive Clustering Hierarchy-Energy and Distance) routing protocol. In order to reduce the data transmission distance of node to cluster head in the cluster, this thesis reselects cluster head in the cluster, and lets cluster head be as close as possible to the centroid for the cluster area to reduce the data transmission distance of node to cluster head, thus it optimizes the energy consumption of sensor nodes and this thesis presents the LEACH-DC (Low Energy Adaptive Clustering Hierarchy-Distance and Centroid) routing protocol. As to the three modification above that are mentioned, this thesis has extendedly installed and modify LEACH program based on the NS2 simulation network platfom, according to the comparision analysis experiment of the improved LEACH-ED, LEACH-DC and the original pairs. In order to guarantee the accuracy of the results, two different sensing node distribution file simulations are made. The results show LEACH-ED and LEACH-DC indeed effectively prolongs the network lifetime and improve the network performance.