The Improvement Of Leach Protocol In Wireless Sensor Networks

Wireless sensor networks (WSNs) is made up of a large number of sensor nodes, which are randomly scattered in the monitored area in general. The sensor nodes form an autonomous network system by wireless communication. WSNs has important applications in remote environmental monitoring, target tracking and so on. And in recent years, the appearance of smaller and cheaper smart sensor enabled the wide use of WSNs.Due to the limited energy and the non-rechargeable battery of the nodes, how to increase the energy efficiency and the lifetime of network becomes one of the most important research fields in WSNs. Merging data before transmitting is the characteristic of hierarchical routing protocol, which can reduce the transmission of redundant data and achieve the purpose of saving energy. Leach protocol is a typical hierarchical routing protocol, but high energy consumption when selecting cluster heads randomly and communicating between cluster heads and the base station is one of the weaknesses of it.In this paper, based on the analysis and research of the Leach routing protocol, aimed at the defects in Leach routing protocol, the standard of choosing cluster heads by taking the energy and location of cluster heads into consideration was put forward. And using the Particle Swarm Optimization (PSO) to select the best energy and distance proportion with different network scales to optimize election of the cluster head nodes in the network. All simulations are realized under NS2. The simulation results show that, using the new method, the network life is longer than the original Leach protocol.