【作者】 张霞；

【导师】 于宏毅；

【作者基本信息】 解放军信息工程大学 ， 通信与信息系统， 2009， 博士

【摘要】 低功耗无线通信、微型传感器设计与制造、自组织组网、普适计算与分布式信号处理等技术的发展,促进了一种新型信息采集网络——无线传感器网络(Wireless Sensor Networks, WSN)的产生和迅速发展。WSN通过大量微型无线传感器节点以自组织协同的方式构成网络,实现对目标(或区域)自动地信息采集、处理与传输。路由协议是支撑WSN信息传输、节点间协同工作的关键技术。由于WSN在网络特点、业务特点和需求等方面与传统无线网络存在显著差别,WSN的路由协议设计面临一系列新的挑战。本文对WSN路由协议的能量有效性问题、带宽资源高效利用问题和数据传输可靠性问题进行深入研究,主要研究成果和创新点如下：1.提出了一种基于协作通信的网络寿命最大化路由策略ORRCR (Optimal Relay Ratio based Cooperative Routing),通过采用中继、协作混合传输模式,克服WSN在衰落信道、多对一通信模式下能耗不均的缺陷。通过定量分析混合传输模式下网络寿命和节点中继概率的关系,将网络寿命最大化问题转化为中继概率的最优化问题。该问题属于非线性优化、难以直接求解,通过深入分析“网络寿命最大化”和“各节点能耗相等”的关系,得到了“网络寿命最大化时,所有节点或部分节点能耗相等”等重要结论,简化了中继概率的求解。基于最优中继概率设计了DORRCR (Distributed ORRCR)协议,有效延长了网络寿命。2.提出了一种带宽资源高效的协同QoS路由策略CQR (Collaborative QoS Routing)其核心是通过对多数据流路由的联合优化,克服单数据流路由优化方法易产生带宽资源碎片的缺陷。把多数据流路由的联合优化归结为多商品流问题。针对无线信道中多数据流路由选择具有空间耦合特性、难以利用经典算法求解的问题,提出一种基于干扰链路集的资源分解方法,将多数据流联合路由优化转化为资源分解矢量的优化问题,并采用次梯度优化的方法求得CQR的最优解。针对集中式算法复杂度高、难以直接应用的问题,设计了基于本地流量转移的分布式协同路由协议LTM_CQR(Local Traffic Migration based CQR),通过定量分析本地拓扑知识半径和流量转移成功概率的关系,优化了协议重要参数,在分布式条件下求得CQR的次优解,提高了带宽资源利用率。3.针对Alice-Bob网络编码结构,证明了两数据流的路径构成编码结构的条件,以及一条路径上相邻编码结构的串联性质；设计了一种尽力耦合的集中式路由算法NCBCR (Network Coding based Best effort Coupling Routing),利用上述结论,对多数据流的路径进行联合调整,构造尽可能多的编码结构,减少了数据流的端到端传输次数。4.设计了一种基于虚拟多路径的可靠路由协议VMR (Virtual Multipath Reliable routing)。该协议不专门发送探测分组,而是利用发送的数据分组收集路径可靠性信息,通过区间估计评估各可行路径的可靠性,并通过差路径过滤的方法实现在数据传输过程中路由选择的逐步优化。仿真结果表明,VMR在能量效率、分组递交率方面优于典型的可靠路由协议AODV_ETX。更多还原

【Abstract】 In recent years, the rapid development in low power wireless communication, microsensor, in conjunction with the significant progress in distributed signal processing, ad hoc networks protocols, and pervasive computing have made wireless sensor networks (WSNs) a new technological vision. WSN is formed by large amounts of micro sensor nodes networking in ad hoc manner which collaboratively gather and deliver information from the objective area automatically. Routing protocol is the key technology of WSN for information gathering and collaboration among sensors.Routing protocol design differs from that in traditional wireless networks because of the limitation of network resource as well as the spectial traffic characteristics and various user demands in WSN. In this thesis, key problems in WSN routing protocol design are investigated including energy efficiency, bandwidth efficiency and transmission reliability. Main research fruits are summarized as follows:1. An Optimal Relay Ratio based Cooperative Routing (ORRCR) strategy is proposed to maximize the network lifetime of WSN in fading channel and under many-to-one traffic pattern which combins forwarding and cooperative transmission modes together. By quantitative analysis of the relationship of network lifetime and relay ratio, network lifetime maximization problem is transformed to relay ratio optimization. High nonlinear characteristic of this problem makes it difficult to obtain optimal solution directly. Through analysis on relationship between network lifetime maximization and equal energy consumption between nodes, important conclusions are reached that "network lifetime is maximized with all nodes and some nodes have equal energy consumption" which simplify the above optimization problem greatly. Distributed routing protocol DORRCR is proposed based on optimal relay ratio. It achieves longer network lifetime.2. A bandwidth resource efficient Collaborative QoS Rouing (CQR) strategy is proposed. The key of CQR is to jointly optimize path selections of multiple flows so as to overcome the bandwidth fragment problem resulted from path optimization focusing on one data flow. The problem is summarized as multi-commodity problem. But because of space coupling characteristic of path selection within multiple flows in wireless channel, classical algorithms can’t work. Interfered Link Set oriented bandwidth resource decomposition is proposed to transform the routing optimization of multiple flows to optimization of resource decomposition vector and the optimal solution is obtained in centralized manner with subgradient optimization method. Because the centralized algorithm is of high computation complexity and is hard to be directly used in WSN, Local Traffic Migration based CQR protocol is proposed; through quantitative analysis of relationship of topology knowledge and local traffic migration success probability, key parameter is optimized. LTM_CQR achieves higher bandwidth efficiency comparing to existed protocol.3. Alice-Bob coding structure is studied in network coding aware routing algorithm. The condition under which paths of different traffics form Alice-Bob coding structures (AB condition, for short) is analyzed and series characteristic of two neighboring coding structure along one path is proved; A centralized Network Coding based Best effort Coupling Routing (NCBCR) algorithm is proposed, which adjusts paths of different data flows based on the AB condition and series characteristic to form as many as possible coding structures. NCBCR outperforms traditional aloghrithms by reducing end to end transmissions.4. A Virtual Multipath Reliable routing protocol is proposed. VMR doesn’t send specialized probing packet for reliability information of wireless link; instead, it sends data packets along possible paths and gather path reliability information at the same time. Interval estimation is used to evaluate quality of the paths and bad path filter method is proposed to dynamically choose the optimal path(s). Simulation shows that VMR outperforms reliable routing protocol AODV_ETX in both energy efficiency and reliability.更多还原