【作者】 彭超；

【导师】 鲁东明； 董亚波；

【作者基本信息】 浙江大学 ， 计算机应用技术， 2008， 硕士

【摘要】 近年来随着无线通信技术、传感器技术和嵌入式技术的飞速发展,无线传感器网络成为计算机科学技术的一个新的研究领域。数据采集网络是无线传感器网络一个重要的应用分支。在数据采集网络中,传感器节点部署在监测区域,协作的实时监测、感知和采集各种环境和监测对象的信息,对其进行处理并发送到观测者。然而,实际应用的环境非常复杂,为了扩展系统部署空间和提高系统的可靠性,通常需要多层次的网络结构。本文回顾了构建无线传感器网络系统的各种协议和支撑技术。通过对数据采集网络的应用场景进行分析,提出了一种典型的多层次网络模型。模型中有传感器网络、转发网络和长距离无线传输网三个层次。簇头节点处在传感器网络和转发网络间,负责收集同簇中传感器节点的数据并在转发网络中发送。中继节点则处在转发网络和长距离无线传输网间,负责收集各个簇头节点的数据向长距离无线传输网中发送。在这种网络模型的基础上,本文主要针对转发网络和传感器网络设计了一种多层次的网络协议,包括路由协议、时间同步协议和MAC层协议。该协议在转发网络中采用修复请求的路由发现机制建立单跳自组织路由,在传感器网络中则采用定向扩散机制建立低功耗自组织路由。另外,协议采用请求应答的方式实现簇头节点与中继节点的实时时钟同步,采用DMTS算法实现同簇中传感器节点的同步工作和实时时钟同步。MAC层协议主要包括间歇工作机制和CSMA/CA机制,间歇工作机制保证节点大部分时间处在休眠状态从而节省能耗,CSMA/CA机制则用来解决无线信道冲突问题。根据数据采集网络的要求,本文设计了传感器节点的硬件平台,并介绍了在这种硬件平台上软件的架构和协议的实现。然后搭建了测试环境,测试了各个层次网络的路由组织性能和网络中节点的功耗性能,达到了预期目标。通过系统在敦煌莫高窟的部署运行,进一步证明了协议的可靠性和节点设计合理性。更多还原

【Abstract】 In recent years along with the rapid development of wireless communication technology, sensor technology and embedded technology, wireless sensor network(WSN) has become a new research area of computer science. In data gathering network, an important application of wireless sensor network, sensor nodes sample, process information of monitored objects and transfer the processed information to users. However, in order to improve scalability and reliability, tiered architecture is usually adopted to fit the complex deployment environment.This thesis reviews existing WSN protocols and analyzes the requirements of data gathering networks, then presents a tiered network model which consists of sensor network, forwarding network and long-distance wireless network. Header nodes, which is the gateway between sensor network and forwarding network, collect data from sensor nodes and transfer the data to relay nodes. While relay nodes, the gateway between forwarding network and long-distance wireless network, are responsible for collecting and forwarding data from header nodes.Based on the proposed model, the thesis proposes the design of a multi-tier protocol which integrates routing, time synchronization and MAC for data delivery in forwarding network and sensor network. Directed diffusion and repair request mechanisms are used for route discovery in sensor network and forwarding network respectively. ARQ scheme is adopted for real-time clock synchronization between header nodes and relay nodes, while DMTS scheme for time synchronization between header nodes and sensor nodes. Duty-cycle working and CSMA/CA mechanisms are two major technologies at MAC layer. Duty-cycle working mechanism is used for power saving, while CSMA/CA mechanism is used to reduce the chance of channel collision.In addition, according to the requirements of data gathering networks, we have developed a specially designed sensor node. After presenting the architecture of software, the thesis focuses on how to implement above protocols on our sensor nodes. Then, the thesis describes h6w to construct the experiment environment and analyzes the performance of experimental system from two aspects -- power-efficiency and network reliability. The thesis also introduces a real system deployment at the Mogao Grottoes in China, a well-known wildland cultural heritage, and the reliability of the above protocols is verified in real deployment environment.更多还原