Abstract-Wireless Sensor Networks (WSN) are getting more and more attention for various applications. In addition, localization plays an important role in WSN. This article focus on the large errors of DV-Hop (Distance VectorHop) localization algorithm in net topology of randomly distributed notes. A CLDV-Hop (Correct Levenberg Marquardt DV-Hop) algorithm in DV-Hop based on modifying average hopping distances is proposed. Firstly, hop count threshold is to optimize the anchor node during a data exchange. The weighted average hop distance of unknown nodes nearest the three anchor nodes are selected as its average hop distance according to the minimum mean square criteria. Finally, L-M (Levenberg Marquardt) algorithm is used to optimize the coordinate of unknown node estimated by least squares. The simulation results show that, under the conditions of existing overhead and for a given simulation environment, CLDV-Hop algorithm has higher positioning accuracy than existing improved algorithms. The accuracy is improved 33%-41% compared with DV-Hop algorithm.
Keywords-wireless sensor networks, DV-Hop algorithm, localization, L-M algorithm
IntroductionWireless Sensor Network (WSN) consists of a large number of sensor nodes distributed in the area with perceptive, processing and transmitting environment information. It is often applied in environmental monitoring, medical service, military investigation, industrial diagnosis and intelligent space [1]. Whatever the field is, researches lack of objectives and sensor nodes localization are meaningless. Therefore, node localization technology has become an important research topic in WSN [2].At present, Global Positioning System (GPS) can achieve the node localization of WSN. However, taken price, volume, energy consumption and environment into account, it is impossible to use GPS massively [3]. Many researchers have proposed 4http://www.i-joe.orgPaper-Iterative L-M Algorithm in WSN-Utilizing Modifying Average Hopping Distances various positioning algorithms, which can be divided into range-based localization algorithms (Range-Based) and range-free localization algorithm (Range-Free) [4]. The former requires measuring absolute distance and angle between neighboring nodes. The latter can only implement localization, based on the connectivity of the network, such as centroid algorithm [3][4][5], convex programming algorithm [6], DVHop algorithm [7] and Approximate Point-in-triangulation Test (APIT) algorithm [8].Range-Based has a higher requirement to hardware and it needs repeated measurements to obtain reasonable positioning accuracy. Therefore, it will cost a large amount of computation and communication. Range-Free positioning mechanism has been used widely in large-scale WSN with its economization, power-saving and simplicity. DV-Hop is a typical Range-Free localization algorithm with simple implementation and high positioning accuracy. However, the positioning accuracy of the proposed algorithm is still inadequate in the random distribution of nodes in the WSN. Many sc...
