基于分簇策略的ZigBee网络路由能量优化方法研究

发布时间：2018-10-25 20:45

【摘要】：ZigBee是一种短距离无线传感器网络标准,以其低成本、低功耗、自组网、体积小等优点成为物联网中解决无线个域网问题的关键技术。ZigBee网络中的节点多采用电池供电,网络中的信息传递效率、网络完整性、网络生命周期等很依赖于各个节点的能量状况,并且ZigBee网络的很多使用场景决定了它在部署后不易于更换电池,所以如何在现有有限能量的基础上尽可能的降低ZigBee网络中节点的能量消耗,保证整个网络的通信效率延长网络的使用周期就显得尤为重要。尽管ZigBee技术自身也采用了一些举措来降低节点的能量消耗,但在降低能耗优化性能上还有较大的改进空间。ZigBee网络层的研究是近些年国内外学者关注和研究的重点,而网络层的标准也在不断的修改完善之中。经典的ZBR算法虽然混合使用了AODVjr和ClusterTree协议,但只是指出了可以使用这两种协议,并未详细说明该如何有效地选择和结合两种算法之间的优势,取长补短。本文在深入研究ZigBee路由协议的基础上,提出了一种基于分簇策略的能量优化算法。本文提出的改进算法采用ME-AODV分簇方法将整个ZigBee网络划分为一个个逻辑簇,通过簇来限制RREQ的洪泛方向,减少大量不必要的路由发现过程和因此产生的RREQ冗余。除了考虑单个节点的能量消耗外,本文算法也综合考量关键节点在整个网络中的能量水平,引入能量等级的概念将节点划分为充足、偏低、警戒三个等级,等级的划分标准是动态变化的,它跟节点的网络深度、网络整体的能量状况相关。每个簇中簇首根据自身的能量状况来决定簇内外该选择何种路由协议,有效结合AODVjr协议的最佳路由和Cluster-Tree协议简单节能的优势。此外还采用了备用节点机制,使得节点在能量较低时可以使用备用的节点继续工作。加入延时因子机制,使得节点在能量偏低时降低自己作为路由中间节点的可能性,较好的避免了某些节点因能量耗尽过快而导致死亡,让整个网络各层的负载更加均衡,减少节点的能量消耗,延长了ZigBee网络的使用寿命。本文对改进后的算法在NS2平台上进行与经典ZBR算法的仿真对比,并对结果进行了详细的研究和分析。通过实验结果的对比可知,在分组投递率,全网节点能量消耗,路由开销百分比,网络延迟,剩余能量百分比这几个指标上都优于传统的ZBR算法。改进后的算法可在一定程度上有效的均衡网络中各层节点负载,减缓节点死亡,降低整体能耗,延长ZigBee网络的生命周期。
[Abstract]:ZigBee is a short-range wireless sensor network standard. Because of its advantages of low cost, low power consumption, ad hoc network and small size, ZigBee becomes the key technology to solve the problem of wireless personal area network in the Internet of things. The efficiency of information transmission, the integrity of the network, the life cycle of the network depend on the energy status of each node, and many usage scenarios of the ZigBee network make it difficult to replace the battery after deployment. Therefore, how to reduce the energy consumption of the nodes in ZigBee network on the basis of the existing finite energy, and ensure the communication efficiency of the whole network to extend the network life cycle is particularly important. Although ZigBee technology has also adopted some measures to reduce the energy consumption of nodes, there is still much room for improvement in reducing the performance of energy consumption optimization. The research of ZigBee network layer is the focus of domestic and foreign scholars in recent years. And the standard of network layer is also in ceaseless modification consummation. Although the classical ZBR algorithm uses AODVjr and ClusterTree protocols, it only points out that these two protocols can be used, and does not explain in detail how to select and combine the advantages between the two algorithms in order to complement each other. Based on the research of ZigBee routing protocol, an energy optimization algorithm based on clustering strategy is proposed in this paper. The improved algorithm proposed in this paper uses the ME-AODV clustering method to divide the whole ZigBee network into logical clusters, which limit the flooding direction of RREQ and reduce a large number of unnecessary route discovery processes and the resulting RREQ redundancy. In addition to considering the energy consumption of a single node, the algorithm also considers the energy level of the key nodes in the whole network. The concept of energy level is introduced to divide the nodes into three levels: sufficient, low and alert. The classification standard is dynamic, which is related to the network depth of nodes and the energy status of the network as a whole. The cluster head in each cluster determines which routing protocol should be selected within and outside the cluster according to its own energy status, effectively combining the best routing of AODVjr protocol and the advantages of simple energy saving of Cluster-Tree protocol. In addition, a standby node mechanism is adopted to enable the node to continue to work with the standby node when the energy is low. By adding the delay factor mechanism, the node reduces the possibility of being a routing intermediate node when the energy is low, which can avoid the death of some nodes because of the fast energy depletion, and make the load of all layers of the network more balanced. The energy consumption of the node is reduced, and the service life of the ZigBee network is prolonged. In this paper, the improved algorithm is compared with the classical ZBR algorithm on the NS2 platform, and the results are studied and analyzed in detail. The comparison of the experimental results shows that the traditional ZBR algorithm is superior to the traditional ZBR algorithm in terms of packet delivery rate, energy consumption of the whole network node, routing overhead percentage, network delay and residual energy percentage. The improved algorithm can effectively balance the load of nodes in each layer of the network to some extent, slow down the node death, reduce the overall energy consumption, and prolong the life cycle of the ZigBee network.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92

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