【作者】 徐宏勤；

【导师】 王智；

【作者基本信息】 浙江大学 ， 控制理论与控制工程， 2008， 硕士

【摘要】 节能降耗以及舒适、便捷的生活和工作环境对室内环境监控系统提出了新的要求,而利用无线传感器/执行器网络(WSAN)监控室内环境无疑会带来新的机遇和挑战。以低成本、高密度、广泛分布为特点的WSAN可以有效地监控室内环境中的能量消耗和提供多种相关决策信息,为科学决策和调度提供高度可信的依据。然而,到目前为止还没有一种针对该室内环境监控系统通信特性的路由协议,这正是本文的主要工作。本文首先分析了面向室内环境监控的WSAN的特点。网络由不同类型的节点组成,即大量的传感器节点和少量的执行器及控制器节点(如灯光、空调等的调节器,各种遥控器等)。传感器节点需要电池供电、计算能力有限;执行器和控制器节点计算能力有所增强,且通常有外部电源供电没有能耗约束;绝大部分节点是静态的,且具有确定的地理位置,但也有少数的移动节点。此外,节点间的通信链路不稳定。基于上述特点,本文提出了一种利用节点异构特性和地理位置的按需路由协议RPWSAHA。RPWSAHA协议由“路由发现”、“位置信息服务”和“路由维护”三部分组成,具有能耗低、简单实用和提供数据可靠传输的优势。“路由发现”过程是RPWSAHA协议的主要过程,我们设计了空间约束型洪泛和时间约束型洪泛两种路由发现策略。前者是一种自适应扩展的地理位置受限的路由请求包定向广播技术,它利用静态节点位置信息限定路由请求包广播空间;而对于移动节点而言,利用其静态邻居作为辅助节点来完成路由发现,不仅避免了对移动节点定位技术的依赖性,而且支持多路径。后者是一种基于稳定链路的路由发现周期延长的路由请求包选择广播技术,在该技术中能量高效的静态节点具有转发路由请求包的优先权,由此找到的路径具有能量高效、稳定的特点,降低了路由发现次数。我们在设计“位置信息服务”时,把移动节点位置信息的注册、更新和查询限制在能量高效且稳定的节点中,这样可以避免过多地使用能量受限的节点。在设计“路由维护”过程时,采用了非本地路由维护算法,该算法在网络规模不大且支持多路径的情况下具有更低的路由开销。和ZigBee支持的AODV相比,RPWSAHA只在位置信息服务过程中引入了少量的额外开销,不仅具有算法复杂度小的特点,而且还具有更优越的性能。我们自主开发了RPWSAHA路由协议的NS源码,并且在三个不同网络规模的场景中分析了路由协议的收包率和路由开销。和AODV路由协议性能测试结果显示,RPWSAHA路由协议在30个节点规模中具有和AODV相当的性能;但是在60和90个节点规模中具有更优越的性能,后两种场景下收包率比AODV提高了40%以上,而路由开销则降低了70%以上。更多还原

【Abstract】 Reducing energy consumption and increasing user comfort propose new challenges to indoor environment control and monitoring system. Wireless Sensor/Actuator Network (WSAN) has the potential to solve many of the problems associated with indoor environment control and monitoring system. WSAN characterized with low cost, high density and widespread can be used to manage energy consumption and provide information related to decision-making. However, there are no routing protocols which meet the characteristics and requirements of indoor environment control and monitoring system integrated with WSAN. Design of such a routing protocol is the main task of this dissertation.In this dissertation, we first analyzed the characteristics of indoor environment control and monitoring system integrated with WSAN. Such system comprises of a large number of sensor nodes and a few actuator/controller nodes. Sensor nodes are usually battery powered and have limited computing power. Actuator/controller nodes have enhanced computing power and are usually main-powered. Static nodes and mobile nodes coexist in this system and most nodes are static. Anther important characteristic of such system is the link instability. Based on the characteristics analyzed above, we proposed a location based on demanded routing protocol named RPWSAHA which comprises of "routing discovery phase", "location service phase" and "routing maintenance phase". RPWSAHA has the advantage of simple, energy efficiency and high reliability."Routing discovery phase" is the main part of RPWSAHA in which we designed two routing discovery strategies: space restricted flooding and time restricted flooding. In space restricted flooding, the broadcasted routing request packets are limited into a small area which is calculated by using static nodes’ location information. This is a localization-free location-based routing discovery strategy in which mobile node’s location is referred by its static neighbors. It also support multi-path. In time restricted flooding, energy efficiency and static nodes have the priority to forward routing request packets. By this way, the route established is energy efficiency and stable. Time restricted flooding can reduce the time of routing discovery thus reduce routing overhead. In the "location service phase", static sensor nodes maintain all the location information for static sensor and actuator nodes. Actuator nodes maintain location information for all nodes. This is based on the fact that the traffic involved in frequently updating mobile node location information could be restricted to actuator nodes that are not battery-powered and are not sensitive to energy consumption issues. In "routing maintenance phase", PRWSAHA routing protocol only support non-localized algorithm for it can reduce routing overhead further when the size of network is small or intermediate and multi-paths exist. Compared with AODV which is supported by ZigBee specification, PRWSAHA only introduces extra time complexity and communication complexity in "location service phase" which are still low.We developed the source code of RPWSAHA routing protocol using NS simulator and analyzed its ratio of packet received and routing overhead in three networks with different scale. The simulation result showed that RPWSAHA routing protocol has similar performance with AODV when the network has 30 nodes. In the network with 60 nodes or 90 nodes, RPWSAHA can increase the ratio of packet received by 40% and reduce routing overhead by 70% in comparing with AODV.更多还原