【作者】 张雪凡；

【导师】 陈惠民；

【作者基本信息】 上海大学 ， 通信与信息系统， 2011， 博士

【摘要】 无线传感器网络由于其具有自组织、成本低、构建灵活等特点,使得在军事、民用等领域应用广泛,已成为当前IT领域研究的热点之一。研究无线传感器网络的一个重要目的是在满足网络应用要求前提下尽可能地延长网络寿命,所以节能研究是无线传感器网络的关键技术之一。本文主要从物理层的电路结构、MAC层的时序运作机制和网络拓扑控制方法出发,研究无线传感网的节能机制。首先,针对无线传感器网络节点周期性睡眠的工作特性,通过分析电路启动过程的时间特性,提出了能耗分层节能控制方法以及每个能耗层的电路设计方案。无线传感器节点需要周期性睡眠来降低能耗,但频繁的启动和睡眠所造成的能耗是很可观的。由于高层协议无法控制物理层的启动过程,因此这个能耗一般常被忽视。本文将无线传感器节点接收和处理信号的过程分为三个阶段,即无线接收阶段,帧格式判断阶段和MAC层处理阶段。这三个阶段对应三个层次的电路能耗。根据监测到的信号特点,通过控制这三个能耗层的工作次序以达到节能的目的。其次,针对无线传感器节点空闲侦听能耗问题,将MAC层与物理层有机结合,提出了两种降低空闲侦听能耗的节能MAC层协议。一种是适合于主从式网络的自适应低功耗无线唤醒协议AWOR (Adaptive Wake On Radio);另一种是适合分布式网络的改进型低功耗准同步MAC协议。AWOR协议基于快速场强监测机制,在无线干扰环境下能够自适应地调整侦听窗口大小,从而降低空闲侦听能耗。在低功耗准同步MAC协议中,采用了时钟漂移的动态预测机制,能够修正时钟的漂移,避免数据的冲突,保证节点的准同步机制正常运行。这种改进型低功耗分布式准同步MAC协议的节点抗毁能力较强,节能效果较好。另外,在节点较密集的无线传感器网络中,针对节点间相互干扰造成的能量消耗,论文提出了一种新型的分簇拓扑控制算法。该算法以功能较强的异构簇头为中心,将一个簇分为内外两层。外层进一步分成若干可以并行工作的子区。该拓扑算法既保留了以簇头为中心控制方式的高效性,又兼有多跳的灵活性。另外,该算法对提高系统的吞吐量,减小节点之间的相互干扰,节约节点能量具有有效性。论文还针对传统的无线多信道MAC协议能耗较高的问题,提出了一种改进的低功耗无线传感器网多信道MAC层协议。该改进协议采用了工作窗口的优先时隙分配机制,动态调整工作窗口的大小,及时控制节点进入睡眠状态,达到节能目的。通过改进,使无线多信道传感网系统在能耗、时延性能方面有较大提升。最后,论文设计了一个低功耗无线传感器网络在燃气抄表中的应用系统。该系统采用自适应低功耗无线唤醒协议(AWOR),设计了一个高层居民大楼燃气自动抄表系统,达到了较好的节能效果。更多还原

【Abstract】 Wireless sensor network (WSN) is self-organizing, low cost and structurally flexible,which makes it widely applied in both the military and civilian domains and it has become one of the most popular researched subjects in the IT field. A vital goal of the research on WSN is to prolong the network lifetime on the premise of network application, thus energy saving is one of the key technologies in WSN. This dissertation focuses on the energy saving mechanism from the following aspects:the circuit structure of physical layer, the timing operation mechanism of MAC layer and the control methods of topology of network.First, based on the performance characteristic of periodic sleep of WSN, this dissertation proposes a control method of energy saving-layered and the scheme of circuit design for each energy consumption layer by analyzing the time characteristic of the circuit start-up process. To save energy consumption, the WSN nodes go to sleep periodically. Because higher layer protocol of WSN could not control the start-up process of physical layer, the start-up energy consumption of physical layer is often neglected. The process of receiving and processing signals of WSN nodes in this dissertation is divided into three phases: wireless receiving phase, frame format decision phase and MAC layer processing phase. The three phases correspond to the energy consumption of the three layers. Energy saving is implemented by controlling the working order of the three energy consumption layers.Secondly, this dissertation proposes two energy saving MAC protocols to decrease the energy consumption for idle listening by combining the MAC layer and physical layer. One is the Adaptive Wake On Radio (AWOR) which is fit for the Master-slave network and the other is improved low power consumption quasi-synchronization MAC protocol for distributed network. The AWOR protocol is based on quick field strength detection mechanism and can adjust the window size of listening adaptively in the wireless interference environment to decrease the energy consumption of idle listening. In the low energy power consumption quasi-synchronous MAC protocol, the dynamic prediction mechanism of clock drift is applied to rectify the clock drift and avoid data conflict to ensure the operation of quasi synchronous mechanism. This improved low energy consumption distributed quasi synchronous MAC protocol has strong invulnerability and better power saving performance.Thirdly, this dissertation proposes a novel Cluster topological control algorithm to solve the energy consumption caused by the interference among the nodes in dense Wireless Sensor Networks. The cluster head is made much more powerful, partitioning a cluster into two rings. The outer ring is further divided into smaller sectors. This topology control algorithm has advantages of both high efficiency in controlling cluster head center, and flexibility of multi-hops. Moreover, this algorithm possesses the efficiency to improve the system throughput, decrease the interferences of nodes and save energy.Furthermore, this dissertation proposes an improved low energy consumption WSN multi-channel MAC protocol based on the problem of the higher energy consumption of traditional protocols. This improved protocol reaches the goal of saving energy by adjusting the size of work window dynamically with the prior time slot allocation mechanism and make nodes into sleep mode timely. The wireless multiple channels of WSN has great improvement in energy consumption and time delay.Finally, this dissertation designs a system of low energy consumption WSN network applied in the gas meter. This system applies the AWOR protocol and designs an automatic meter reading system and achieved good effect of saving energy.更多还原