The Research And Improvement Of LEACH Clustering Routing Protocol For WSNs

Wireless Sensor Network is an intelligent private network in which a large number of sensor nodes transmit information by means of self-organized wireless communication so as to accomplish a specific function collaboratively. Sensor node, with limited energy, usually runs in a hostile and hazardous remote environment where is inaccessible for human beings,Meanwhile, it is not practicable to supplement energy by replacing the battery. Therefore, the key issue for WSN involves in how effectively use the energy of each node for routing forwarding, and design efficient routing protocols to extend the network lifetime.This thesis first introduces the concept, systematic construction, characteristics and application of the wireless sensor network, then explicate and compare the existing WSN routing protocols. We put emphasis on the Low Energy Adaptive Clustering Hierarchy (LEACH) routing protocol. The LEACH protocol circularly and randomly selects cluster head nodes and distributes the whole network energy load into each node evenly, thereby reduce energy consumption and prolong network life. However, in this algorithm, each cluster head is selected randomly in equiprobability, without taking into account factor like the residual energy of nodes, this may result in the selection of non-optimal cluster heads thus further affect the entire WSN lifetime. The distance between base station and cluster head nodes is often too far, data transmission will cause a large amount of energy consumption. For this reason, given the deficiency of LEACH protocol in cluster heads selection strategy, a novel selection mechanism(LEACHIMP) is proposed. This protocol fully considers the residual energy of the nodes, the inter-cluster multi-hop data transmission etc.,In the cluster head election stage,by limiting the low energy nodes in the cluster head selection,the timer mechanism is put and the threshold formula is improved,this can ensure the robustness of the selected cluster head;In the data transmission phase,multi-hop data transmission mechanism between cluster head is been taken in,greatly reduce the additional energy consumption caused by long distance data transmission.At last, NS2 simulation platform is adopted for simulation and performance evaluation to the proposed routing algorithm. Simulation results analyzed and show that the LEACH_IMP protocol has desirable performance in prolonging network lifetime, reducing energy consumption and improving data reception of the base station.