Research Of Node Localization Algorithm In Wireless Sensor Networks

A Wireless Sensor Network (WSN) refers to a group of inexpensive sensors linked by wireless medium, works as a self-organized and multi-hop network. In wireless sensor networks, sensor location plays a critical role in many applications, Without nodes' position, the gathered information is of little worth. So, to locate where the event happen or get the position of the node which received messages is one of the most fundamental functions of WSN.The main work of this thesis is to research and design node localization. First the basic theories of WSN are introduced; the concept of localization is explained; the localization algorithms in existence are classified based on their characteristics; and the performance evaluation standards are noted; the facing challenges in WSN are sorted. Several classic localization algorithms are analyzed and compared by their complexity, performance, precision and application situation.Secondly this paper proposes a algorithm for unknown nodes under three anchor node's condition in wireless sensor networks based on AOA (angle of arrival) method and the geometrical relations among sensor nodes. The simulation proves the effective localization of the unknown node. Meanwhile, this method is only reply on the information of AOA to determine the location of nodes, the proposed method, thereby, reduces processing complexity while saving the energy of nodes which extends life expectancy of nodes.Finally this paper proposes an algorithm based on the mobile anchor nodes. In this method we make use of the TOA (time of arrival) and the geometrical relations among unknown nodes and anchor nodes to obtaining the unknown nodes coordinate. This method is only reply on the two positions of the mobile anchor nodes to determine the location of the unknown nodes, the proposed method, thereby, reduces the spending of communication and computing in wireless sensor networks, while reducing processing complexity.