Research And Improvement On Routing Protocols Of Wireless Sensor Networks Based On Cluster

Wireless sensor networks are a kind of wireless networks consisting of a large number of stationary or mobile sensors, in which sensors communicate with each other by self-organization and multi-hop manner. Wireless sensor networks achieve data collection, processing and transmission. Due to the features of low power consumption, low-cost, distributed and self-organization, wireless sensor networks are widely used in military, aerospace, anti-explosion, disaster relief, environment, medical treatment, health, home, industry, business and other fields.Wireless sensor networks are data-centric networks. In order to obtain accurate data, hundreds of thousands or even more sensor nodes are deployed in the monitoring area. Sensor nodes are assembled with communication module, perception module and calculation modules. The energy of sensor nodes is largely consumed by CPU and wireless transceiver. In general, relatively high power is consumed by wireless communication. According to statistics, the energy consumption of data transmission accounted for 80% of the entire sensor network energy consumption. However, the sensor nodes are usually powered by batteries. In other words, completing the sensor node deployment, it is difficult to replace the batteries. Therefore, how to keep the energy balance in wireless sensor networks to effectively extend the life cycle is one of the main problems of the study.This paper focuses on routing protocols for WSN. It summarizes the flat routing protocols, hierarchical routing protocols, and compares the performance for different parameters, as well as selects the most classic routing protocol, LEACH, as the research object at last. Finally, in order to save nodes’ energy, balance network load, improve the ability of data transmission of nodes and prolong the network lifetime, this paper studies the following tasks:(1) A LEACH protocol based on Based on Nodes’ Remaining Energy and Location(LEACH-E-D) is proposed. This protocol is built up based on LEACH protocol, introducing two main parameters of the node residual energy and the average distance of the temporary cluster. They are separately used to select the temporary cluster heads and the final cluster heads. The simulations are implemented by the powerfully tool OMNET++4.0. After strict designing and patient data collection, meaty results of the experiment are acquired. By comparing with LEACH protocol, in the aspect of mean residual energy, LEACH-E-D performs better. In the case of the same number of nodes, the lifetime of LEACH-E-D protocol extends about 50 seconds than LEACH. Further, with the number increasing, the advantages are highlighted. When the number of nodes is 100, the lifetime extends nearly 75 seconds in LEACH-E-D protocol. As a result, the network load is more evenly assigned and the network lifetime is extended.(2) A LEACH protocol based on Based on multipath and Nodes’ Energy(ME-LEACH) is proposed. This protocol is built up based on LEACH protocol, considering distance factor of inter-cluster communication and residual energy.The cluster head election mechanism based on the estimate of the node residual energy was optimized.Both the energy of the nodes and the distance between the cluster member nodes and the sink node were considered. The cluster member nodes communicated with sink node directly rather than cluster head nodes,which were closer to the sink node than cluster head.The simulations are implemented by the powerfully tool OMNET++4.0 and MATLAB. After strict designing and patient data collection, meaty results of the experiment are acquired. By comparing with LEACH protocol, in the aspect of node dead numbers, ME-LEACH performs better. The first point of death in ME-LEACH emerges 700 rounds later than LEACH. The 50% and 100% point of death in ME-LEACH emerges 900 rounds later than LEACH. ME-LEACH prolongs the network’s lifetime and network stability is improved greatly. At the same time, the performance in sink nodes receiving packets is relatively good which ME-LEACH holds 6 times to the LEACH at about 2800 rounds.