| Wireless Sensor Networks(WSNs)has been widely used in many fields such as agricultural production,water quality monitoring and health care,and provides new means for information acquisition.Generally,WSNs consists of low-cost,low-power and small-size multiple sensor nodes.These sensor nodes are usually powered by limited-energy batteries,and they will continue to operate until they run out of power once deployed in the monitoring area.Therefore,one of the key technologies for studying WSNs is to design a routing protocol that can effectively reduce the network energy consumption and significantly prolong the network lifetime while guaranteeing the efficiency and reliability of data transmission.This article is based on "Working in Projects" under the Erasmus+ international exchange student program at Xi'an University of Posts & Telecommunications-Leipzig University of Telecommunications in 2016.The paper takes the application requirements of WSNs in water quality parameter monitoring as the starting point,and studies the topology structure of the network and the transmission of sensing data respectively,and proposes a WSNs clustering routing algorithm based on the improved gray wolf optimizer.The main works of this thesis are as follows:(1)Considering that the method of randomly selecting cluster heads in the LEACH algorithm will lead to the situation that the cluster heads are scattered or concentrated in the network,the initial clusters are introduced.Using the node's distance median algorithm,a certain percentage of initial cluster heads are selected at equal intervals to form a uniformly distributed initial clusters,thereby balancing energy consumption among nodes in the network.(2)In the basic of gray Wolf optimizer(GWO),the weights of prey location are improved by considering the wolves' fitness value(FIGWO),and a clustering algorithm based on FIGWO is proposed.The algorithm maps gray wolf individuals into sensor nodes in the network,calculates the fitness value of each individual with its remaining energy and distance information,and uses the fitness values of the first three gray wolf individuals to redefine the prey location function.Finally,the improved grey wolf optimizer is applied to the cluster head selection stage to select the more appropriate cluster head.(3)In the LEACH algorithm,all the nodes in a cluster communicate with the cluster heads,so that the energy consumption of the nodes in the cluster head and some nodescloser to the base station increases,and the shortest path transmission technology is introduced.That is,when the distance to the cluster head distance is greater than its distance to the base station,the node directly sends the data to the base station.The clustering routing algorithm proposed in this paper optimizes the cluster structure,reduces the number of member nodes in the cluster,reduces the data receiving energy consumption of the cluster head,and reduces the data transmission distance of some nodes.On the other hand,the number of data packets received by the base station is increased,which enabling the base station to obtain more abundant information.Simulations show that the FIGWO algorithm extends the network lifetime by 57.8% and 31.5%,respectively,compared to LEACH and SEP protocols,and increases the number of packets sent to the BS by 177% and 145%,respectively. |
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