Research Into Node Localization Algorithms In Wireless Sensor Networks

Wireless sensor network, which combines sensor technology, information processing and network communication technology, is a new wireless network with no infrastructure. In the actual applications, the localization of sensor nodes plays important role on WSN. The researchers have proposed many effective solutions for the faults of these algorithms. However, there are still many problems on localization accuracy, positioning coverage, and efficiency orientation.First of all, based on a number of related literatures, this paper discusses the architecture and characteristics of sensor networks, and explains the importance of localization of the sensor nodes; secondly, it analyses the existing localization algorithm and summarizes the current theories, classifications and characteristics. Finally, the major work and new ideas of this paper are as follows:Firstly, this paper proposes a localization algorithm with one mobile beacon, which is called Similar Triangle Localization (STL) algorithm. STL is based on a single mobile beacon aware of its position. The mobile beacon locates the region via special trajectory. The sensor calculates their coordinate by two similar triangles. The advantages of this algorithm are simple and reduce hardware costs.Secondly,in order to increase the performance of APIT algorithm, this paper provides LAPIT algorithm by every located-node label. When other nodes extend the range of the PIT test, the nodes will use labels information of marked-nodes to determine themselves. Some problems for example the in-to-out and out-to-in had been solved.Thirdly, based on the classical self-location algorithm--DV-Hop (distance vector-hop) algorithm, this paper proposes an algorithm called Balance DV-Hop, which makes an improvement on the estimation of the distances between adjacent nodes as well as the calculation of the distance from the target node to the anchor node. BDV-Hop algorithm puts forward the concept of equilibrium coefficient; the equilibrium coefficient makes the localization accurate.Finally, each chapter gives the simulation and performance analysis about location accuracy and coverage rate.The simulations prove each algorithm proposed in this paper, which has improved the localization ability. In STL algorithm, there are concrete experiment process and results, which strongly verify the advantage.