【作者】 贾玉福；

【导师】 董天临；

【作者基本信息】 华中科技大学 ， 电磁场与微波技术， 2007， 博士

【摘要】 基于资源受限的若干关键技术问题一直是困扰WSN迈向成熟的瓶颈。围绕微波无线通信的特点设计低功耗的WSN应用算法正成为解决上述瓶颈的一个有效途径。通过适当控制WSN节点密度、使冗余节点在大部分时间处于休眠以节省能量,研究网络区域内的节点能耗分布以指导其部署策略,将能量有效性设计思想与计算可行性的安全算法相结合解决微波无线通信安全问题,将网络层知识用于指导节点的MAC层无线接入以实现DPM机制的跨层协议设计等都是解决上述问题的必然策略。本文通过将微波无线通信网络建模技术、理论分析方法与网络仿真技术相结合,对WSN基于资源受限的若干相关关键技术问题进行了深入的研究。本文围绕微波无线通信资源受限的特点,对WSN网络体系结构的网络通信协议、网络管理以及应用支撑技术三部分进行了详细综述,分析了目前传感器网络进一步发展亟待解决的资源受限相关技术问题。通过对WSN网络体系结构相关关键技术问题的概括和总结,为本文在微波通信基础上所研究的包括节点密度控制、节点能耗分布估计在内的能量有效性相关问题以及安全问题和协议跨层设计等,提供详细的技术方法与基础理论研究支持。研究了WSN在微波无线通信资源受限条件下利用节点密度控制达到网络能量有效性的相关问题。通过覆盖效用范围与连通效用范围之间的几何分析与证明,简化了区域覆盖与网络连通性问题的一致性策略。为了比较分布式密度控制算法的优劣,提出了WSN密度控制问题的整数线性规划(ILP)普遍表达形式。针对不同覆盖区域的WSN应用覆盖度需求,与以往基于充分条件的状态转移判断原则不同,提出了基于蒙特卡罗算法的节点密度控制机制和覆盖冲突避免与随机退避机制。与其他覆盖控制算法相比,本文提出的蒙特卡罗算法不仅可以以较少的活跃节点对覆盖区域完成覆盖,还可动态控制节点覆盖效用范围内子区域的覆盖度。同时,本文提出的覆盖冲突避免与随机退避机制可以保持网络的稳定性。研究了基于能量有限的节点能耗分布估计以便指导WSN网络部署的能量有效性相关问题。比较了收集型与协作型两类微波无线通信网络的网络寿命求解模型。通过对节点能耗建模与轴对称网络均匀部署建模以及能耗分析,提出了网络节点能耗EC估计曲线。通过推导得出结论:为了最大化网络寿命,基站的最佳位置应位于信息重心。与其他针对协作型网络所做的网络寿命上限研究模型相比,本文提出的EC能耗曲线提供了对传感器网络监测域内节点的能耗分布估计,即可为能量有效性的网络部署提供理论指导,又可为评价路由协议的能量有效性提供了一个绝对标准。研究了资源受限的WSN微波无线通信安全算法,分析了在能量约束,无线通信带宽、计算处理能力等资源受限条件下安全算法应用的局限性以及网络易受到的攻击方式。对椭圆曲线密码ECC算法在WSN中的可行性进行了论证。提出了基于单向累加器OWA和Bloom Filter相结合的节点认证机制,针对WSN节点的特点分析了两种算法的加强方案。相比于WSN的预共享密钥与随机密钥预分配机制,本文提出的认证机制在满足节点资源需求的条件下,即可以使网络内任意节点之间建立安全连接,又可以支持网络节点的动态加入与退出,同时不会使攻击者俘获局部节点便造成全网瘫痪。研究了基于资源受限的微波无线通信协议跨层设计问题。从微波无线通信信道的特点、接入方式和WSN应用的网络体系结构特征三个方面论述了跨层协议设计的必要性。通过深入分析Zigbee协议栈的结构特点及其两种无线通信机制在点对点网络里应用的局限性,将系统运行周期分为三类阶段,提出了CSMA/CA与TDMA无线接入相结合的跨层方案,引入节点的“盲等”策略实现数据传输阶段与路由恢复阶段的交替。与AODV+S-MAC等基于DPM的无线接入机制相比,本文提出的跨层方案可获得更高的数据包接收率、更低的数据包传输延迟和基站接收包的平均系统能耗。更多还原

【Abstract】 The key technology based on resource limited is still the bottleneck for WSN to be mature. Designing WSN application algorithm with lower energy cost under microwave wireless communication is an effective way to solve the bottleneck above. Such energy-efficient strategies based on resource limited involve many aspects such as density control, energy consumption distribution estimation and node deployment, wireless comnicaiton security, crosslayer design of wireless communication protocol and so on. This thesis conducts detailed research on certain key technologies of WSN based on resource limited through modeling the microwave wireless communication network, the theoretical analysis method and the network simulation technology.Communication protocol, network management and application-based technology of WSN’s architecture are first discussed in detail by taking microwave wireless communication as a core and some essential technical questions to be solved before WSN be further developed are analyzed. The summary of the essential technology of WSN provides the detailed technical method and the basic theory research support for the study on the key technology problems based on resource limited such as density control, network lifetime, security problem and cross layer design based on microwave communication.Density control of WSN with microwave wireless communication is studied. The thesis educes a consistency strategy to solve these two fundamental problems by the analysis of geometric relation between the coverage and the connectivity. In order to compare the capability of distributed density control algorithm, it proposes the integer linear programming ILP universal expression form of density control problem. In view of different coverage degree, different from the state transformation principle based on sufficient condition of coverage, the thesis proposes an algorithm based on Monte Carlo algorithm to test whether the nodes are redundant or not and establishes the coverage collision detection and stochastic back-off mechanism. Compares with the CCP algorithm, this plan may not only coveres the region by less active nodes, but also dynamically regulates coverage degree of node’s coverage effectiveness sub-scope. Meantime, the proposed coverage collision detection and stochastic back-off mechanism can maintain the stability of network.The network lifetime upper bound and the estimation of node energy consumption distribution based on limited energy are studied to give an instruction for deploying nodes. The thesis elaborates two solution models on the network lifetime upper bound of the collection and the cooperation microwaves wireless communication network. Through modelling energy consumption of node and symmetrical network deployment, as well as the energy consumption analysis, the thesis proposes node energy consumption EC estimation curve. It draws a conclusion that the sink should be located on the information center of gravity for maximizing network lifetime. Compares with the other lifetime upperbound solving model of cooperation network, the proposed EC curve can grasp the energy consumption distribution in the sensor network monitor territory. It can also provide an absolutely standard for appraising the energy availability of route protocol.The microwave wireless communications security questions of WSN based on resource limited are studied. The thesis analyzes the limitation of the ordinary security algorithm applied to WSN as well as the attack form encountered by WSN on the condition that the energy, the wireless communication band width, computation ability and so on have been limited. The feasibility of applying Elliptic Curves Cryptography ECC algorithm to WSN is discussed. The thesis presents an authentication mechanism based on one-way accumulator and Bloom Filter, does a detailed analysis of its security and consolidated program. Compares with Pre-Share Key and Random Key Predistribution, it can know that this mechanism can not only establish a safe connection between any two valid nodes, but also supports nodes joining in or withdrawing from WSN dynamically. It can also prevent attacker from destroying WSN by seizing a little nodes.Energy-efficient cross-layer design of the microwave wireless communication protocol applied to WSN based on limited communication resource is studied. The thesis expounds the necessity of cross layer design from three aspects such as the characteristic of microwave wireless communications channel, wireless access method and the network architecture of WSN. Through analyzes the features of Zigbee protocol stack and the application limitation of two kind of wireless communication mechanisms thoroughly, the thesis proposes a cross layer plan to make node wireless access with TDMA and non-beacon communication mode alternately. For the time slot assignment problem caused by change of network topology, the thesis proposes a strategy called“blind waiting”. Compares with AODV+S-MAC, this plan can obtain higher packet receiving rate, lower packet transmission delay and lower average system energy consumption.更多还原