【作者】 穆嘉松；

【导师】 刘开华；

【作者基本信息】 天津大学 ， 电路与系统， 2012， 博士

【摘要】 随着无线网络技术的迅速发展，多种短距无线通信标准应运而生。其中，ZigBee技术以其功耗低、价格低廉、性能可靠等优点，在工业、农业、军事、建筑自动化、安全系统、远程监控、智能家居、医疗卫生等众多领域得到广泛的关注。对于短距无线网络系统，路由协议是最重要的组成部分之一。特别是ZigBee技术以低能量消耗为首要目标，提升路由性能对于降低节点功耗、延长网络生存时间有重要的实际意义。ZigBee标准同时支持分层树型路由和Z-AODV路由，可在不同的应用场合兼顾路由效率和路径鲁棒性等需求。然而，由于ZigBee技术应用领域广泛、环境情况复杂，目前对其路由方法的研究还不能完全满足实际应用的要求。例如，对ZigBee网络中两种路由方法性能的分析还不充分；能适应节点移动性变化的路由算法性能还有待于提高等等。为了解决上述问题，本文在详细分析ZigBee网络特性和现有ZigBee路由算法的基础上，从不同路由方式的性能分析、路由选择等方面对ZigBee网络的路由性能改善问题进行了深入研究，主要内容包括以下几个方面：(1)在不同网络稳定性条件下，深入分析了现有ZigBee路由方法的性能，并提出一种自适应的基于节点移动性的路由选择策略(BNM)。策略以利用网络中效率最优的路由方式为出发点。首先分析了不同路由方法在各类无线环境中的性能，得到不同路由方法适用的网络条件。在此基础上，提出自适应路由选择和阈值设定策略。在不引入额外数据通信需求的前提下，通过观测节点位置改变引起的命令收发和自身参数变化，获取节点移动信息并以此为依据自适应选择路由方式。仿真测试结果表明，该策略比传统的单一路由方式有更低的网络总体流量和更高的数据传输效率。最后分析了该策略的硬件开销，表明该策略对ZigBee设备没有额外的存储空间和计算能力的要求。(2)随着ZigBee技术应用的扩展，适应较复杂环境的路由算法成为研究热点。本文详细研究了增强型分层路由算法(EHRP)，分析了节点移动性变化对其性能的影响。在此基础上，将EHRP算法引入基于节点移动性的路由选择策略，提出一种适用于高端ZigBee设备（计算能力强且片上资源丰富）的增强型路由选择策略(EBNM)，实现不引入额外数据传输的节点移动判断和路由方式选择。仿真测试了EBNM算法的数据传输效率，结果表明相对于原有的路由策略和单一路由方案，EBNM策略可以进一步提升ZigBee网络的路由性能。(3)针对基于节点移动性的路由选择策略中判断节点运动的问题，对于抑制路由发现、使能路由发现和增强抑制路由发现等路由方式，分别提出了基于节点信息的运动判定方法。上述方法仅需监测节点本地的命令收发和邻居信息变化，无需节点间的额外数据传输，从而节约了通信带宽，为基于节点移动性的路由选择策略的实现提供了必要的技术支持。(4)深入研究了分层路由和Z-AODV路由在不同网络条件下的性能，以及节点数量和移动性等因素对ZigBee路由方法性能的影响。仿真结果说明强制路由发现方法由于网络过载，在各种情况下都有最差的性能；抑制路由发现方法在稳定网络中的表现优于使能路由发现方法，而后者随着节点移动性的增加，表现逐渐优于前者。进而得到抑制路由发现算法适合稳定网络；使能路由发现方法在节点移动性较高的网络中可带来更高数据传输效率的结论，为研究路由选择策略奠定了基础。更多还原

【Abstract】 With the rapid development of wireless network technique, manifold standards for short-range wireless communication emerge as the times require. Thereinto, the ZigBee specification, which has the virtue of low consumption, low cost and high reliability, arouses wide concern in the field of industry, agriculture, military, building automation, security system, remote control, smart home, health care and etc.The routing protocol is one of the most important components of short-range wireless network system. It is of great significance to reduce the node power dissipation and expand the lifetime of network for improving the routing performance, especially in ZigBee specification whose goal is low energy cost. The hierarchical tree routing and the Z-AODV routing are both available in the ZigBee specification to meet the requirements such as routing efficiency and network robustness in different applications. However, due to the extensive application of ZigBee technique and the complicated environmental situation, the research on routing methods so far could not completely meet the requirements of practical applications. For example, the analysis of the performances of the two routing methods is still not sufficient and the performances of routing algorithms which may fit the change of node mobility remain to be improved. To solve above problems, based on the analysis of ZigBee networks and existing routing algorithms, this thesis focused on the study of routing performance improvement in the aspects of the performance analysis of different routing methods and routing selection. The major contribution of this dissertation is specifically stated as follows:(1) Based on the research on routing performances of different routing algorithms in different network stability in ZigBee networks, the routing selection strategy based on node mobility (BNM) was proposed. The strategy is based on the idea of utilizing the most efficient routing method in the networks. Firstly, the routing performance of different routing methods in different network conditions was analized, based on which, the strategies of self-adaptive routing selection and the setting of threshold were proposed. The node mobility information was acquired without extra data communications by inspecting the data command and the change of node parameters caused by node movement. On that basis, the routing method was chosen adaptively. The simulation results showed that the strategy had better performances on network load and data transmission efficiency than traditional single routing method schemes. Finally, the hardware requirement was analyzed and results showed that the strategy had no extra requirements for memory cache or computing capacity for ZigBee devices.(2) With the extension of ZigBee application, the ZigBee routing method which adapts to complex environment is becoming the research hotspot. The enhanced hierarchical routing protocol (EHRP) was studied in detail and the effect of the change of node mobility on its performance was analyzed in this paper. Based on this, the EHRP was introduced into routing selection scheme, and an enhanced routing strategy based on node mobility (EBNM) was proposed to fit for advanced ZigBee devices (with powerful caculating capacity and abundant peripherals on chip). The node moving estimation and routing selection method without extra data communications were designed. The data transmission efficiencies of different routing strategies and algorithms were simulated and compared. The results showed that, compared with orginal routing selection strategy and single routing schemes, EBNM may improve routing performance and data transmission efficiency.(3) Aimed at recognizing node movement in routing selection strategy based on node mobility, the methods of judging node movement based on node information for suppressed routing discovery, enabled routing discovery and forced routing discovery schemes were proposed respectively. The methods only need to inspect the local command and the change of neighbour node information, while the extra data communications between nodes were not necessary. In this way, the bandwidth was saved and it provided essential technical support for the routing selection strategy based on node mobility.(4) The routing performance of hierarchical routing and Z-AODV routing in different network environments was studied in ZigBee networks. The effect which the node number and mobility have on the performances of ZigBee routing algorithms was analized. The simulation results showed that the forced routing discovery method always have the worst performance due to its network overhead; the suppressed routing discovery method performed better than the enable routing discovery method in stable network; while the latter gradually beats the former as the node mobility increased. It may conclude as the suppressed routing discovery method is fit for the stable networks; while in the network where the node mobility is higher, the enabled routing discovery method may lead to better data transmission efficiency. The conclusion laid a foundation for the research on routing selection strategy.更多还原