【作者】 刘伟娜；

【导师】 常铁原；

【作者基本信息】 河北大学 ， 通信与信息系统， 2019， 硕士

【摘要】 无线传感器网络(Wireless Sensor Network,WSN)是由大量的传感器节点以无线自组织和多跳的方式构建成的网络。所有的传感器节点在待测区域内协同合作,进行数据的收集、处理和无线传输。但是传感器节点使用电池供电,部署位置常常是无法控制的区域,更换电池无法实现,节点能量耗尽后将会导致网络系统崩溃。因此,实现节点能量的低消耗高利用率进而延长网络生存周期是当前亟待解决的重要问题。首先,本文对WSN及其路由协议进行了研究,介绍了WSN的系统结构、路由协议的特点和分类,列举了典型的WSN路由协议。然后,重点对LEACH协议进行分析和改进,主要工作如下:1.针对LEACH协议中的簇头随机选择问题,综合考虑了能量和距离两方面的因素对簇头选择阶段进行优化。将节点剰余能量的平均值和标准差、节点与基站之间的距离作为权重参数引入到原阈值概率中,构成新的阈值判定公式,并根据其进行簇头节点的选择,使距离基站近,剩余能量多并且能量变化小的节点更有可能成为簇头。2.针对LEACH协议中的成簇不均匀问题,综合考虑了能量和距离两方面的因素对节点入簇过程进行优化。在节点选择簇头节点时,加入一个由簇头节点能量和节点与簇头之间距离等参量共同决定的节点入簇依据,各节点根据此依据值的大小选择合适的簇头入簇,使分簇更均匀,减少极大极小簇。3.针对LEACH协议中的簇头数量不稳定问题,引入网络运行过程中每轮的最优簇头数目。结合该协议的能耗模型和节点成簇过程,计算出工作一轮网络的总能耗和簇头数目之间的关系,以节点总能耗最少为条件,进而推导出最优簇头数目的计算公式,使得网络运行过程中簇头节点的数目上下浮动范围更小。最后,对上述改进措施使用MATLAB和OMNeT++软件进行了仿真实验,分析实验结果得到改进协议使网络分簇和簇头节点数量更均匀,有效均衡了网络能耗,延长了网络生存周期。更多还原

【Abstract】 The wireless sensor network is composed of a large number of sensor nodes in a self-organizing and multi-hop manner.All sensor nodes cooperate in the area to collecte,process and transmit data.However,sensor nodes are usually battery-powered,and they are often be located in an uncontrollable area.It is unable to replace the battery.If the node’s energy is exhausted,the network system will crash.Therefore,achieving low consumption and high utilization of node’s energy and prolonging lifetime of the network is an important problem.First,this paper studies wireless sensor networks and their routing protocols,gives the system structure of the wireless sensor network and the characteristics and classifications of the routing protocol,and lists some typical wireless sensor network routing protocols.Secondly,put the focus on the analyzing and improving of LEACH protocol.The main contents and achievements are follows:1.To solve the problem of cluster head selecting in LEACH protocol,this paper optimizes cluster head selecting process by considering energy and distance of nodes.The improved algorithm considers the mean and standard deviation of the residual energy and the distance between the node and base station as a weight parmeter introduced into the original threshold to form a new threshold.It makes nodes who is closer to the base station and has more residual energy more likely to be chosen as cluster heads.2.To solve the problem of uneven clustering,this paper optimizes clustering process by considering energy and distance of cluster heads.In the clustering process,it adds a clustering-threshold which is calculated based on the energy of the cluster heads and the distance between the node and the cluster head.This make nodes select a more appropriate cluster head according to the value of this threshold.This improvementreduces the number of maximum or minimum clusters.3.To solve the problem of unstable number of cluster heads,this paper adds the optimal number of cluster heads in the network.Firstly,find the relationship between the total energy consumption and the number of cluster heads according to the energy consumption model of the network and the clustering process.Then,recken the formula for calculating the optimal number of cluster heads.This improvement narrows the range of cluster heads up and down through the operation of the network.Finally,the improvement of LEACH protocol by the MATLAB and OMNeT++simulation software.The simulation results show the improvement in this paper can balance clustering,the number of cluster heads and network load,and extend the network lifetime.更多还原