The Study On Range-Based Node Localization Algorithm Of Wireless Sensor Networks

Wireless Sensor Networks (WSN) is becoming one of the most promising technologies in recent years. It is a new pattern of information gathering and processing which integrates technologies of micro-electro-mechanism, embedded computing, distributed information processing and wireless communication. Node localization, topology control, routing protocols are some of the fundamental problems of WSN. Among these problems, node localization has been focused as a basic factor for that it is the precondition of many applications of WSN, such as target identification, surveillance and tracking. Furthermore, some routing schemes, information of network coverage, load balance, topology control of WSN depend on the location information of the nodes in networks. So, the study for node localization of WSN possesses great significance in the theory and practice, and it will become an important part in the research area.Since the nodes are restricted by size, cost and energy, and WSN always works in the environment which is hard to be accessed, the traditional localization methods of wireless networks can't fit the WSN well. The special localization technologies should be designed for WSN. This paper expounds the system architecture, features and applied fields of WSN. Based on this, it thoroughly analyzes the localization technologies of WSN.As summarizes the existing localization algorithms and compounds the features of WSN and localization request, this paper proposes a localization algorithm based on RSSI (LABOR). The algorithm adds advanced nodes to be beacon nodes in order to assist in localization. The advanced nodes have enough energy and large radio power. Their communication fields can ranges the whole WSN. LABOR changes the method that the nodes receive localization information passively. In this algorithm, nodes which need to be localized send requests actively. The beacon nodes process the requests cooperatively. At last, nodes use Monte Carlo method to estimate their positions. Because of just localizing some nodes which have requests, the algorithm is easy to use. It has fewer communication packages, so it lessens the energy consumption of the whole nodes and extends the living life of WSN. Furthermore, the algorithm in this paper raises localization accuracy by setting range emendation weight and select beacon nodes optimizingly.In the end, this paper simulates the algorithm in MATLAB for different network deployments. The simulation result shows that LABOR is a robust algorithm. It is suitable and extendable for randomly-deployed WSN.