Research On Energy Efficient Target Tracking Protocols In Wireless Sensor Networks

Wireless sensor networks (WSNs) are formed by a large number of cheap micro-sensor nodes through mutual cooperation, which can carry out effective monitoring on a wide range of regions, thus it is widely used in different applications such as military battlefield, environmental monitoring, intelligent transportation system, medical diagnosis and other fields. Target tracking is a basic application of wireless sensor networks. However, because of the uncertain movement of a moving target, it becomes a challenging issue for locating and tracking a moving target while considering quality issues.In order to tackle this problem, we propose a target tracking protocol based on a dynamic group. A sensor node has three modes, namely, sleep, monitor and tracking. A node scheduling mechanism is designed to maintain the sensor modes, which allows the nodes to be in sleep mode while the target is not in the sensing region and the neighbour nodes wake up in time to monitor the target and forward the monitoring data to the leader node once the target appears. We also set a weight value for each monitoring sensor. According to the weight value of the node, it can be determined whether the node needs to participate in tracking or not. At last, a method, leading nodes adaptively forwarding data reports, is designed, which can dynamically adjust the frequency of data reporting according to the movement of the target. Performance analysis and simulation results show that the proposed protocol effectively improves the energy efficiency.In this thesis, we also propose a method based on the Delaunay triangle to utilize the Delaunay triangulation and Voronoi partition to regularize all of the nodes which are disorder on geometric position in the network. Hence each node has geometric characteristics of the Delaunay triangle. Then we combine the uniqueness of Delaunay triangle with the application of target tracking by making only the three vertexes of the Delaunay triangle to involve in target tracking. Therefore, three nodes sense and exchange information to locate the target in that Voronoi triangle, one of the active nodes become as a beacon node. Other two nodes cooperate the beacon to locate the target. In this way, the target tracking protocol reduces the number of nodes involved in tracking and effectively improves the energy efficiency.As the goal of designing a target tracking scheme, it should be able to accurately track the target in an energy efficient manner. The proposed two schemes take the advantage of efficiently using sensor networks for target tracking applications, and effectively improve the energy efficiency of the network, which will be valuable for other researchers designing related tracking protocols.