Research On DV-Hop Localization In Wireless Sensor Networks

At present, the rapid development of science and technology, new technology changes with each passing day like appearance, information on the constant pursuit of innovation and a growing number of new intelligent high sophisticated sensor equipment production great development of the wireless sensor network(WSN). it access to information is one of the most important and most basic sensor technology has been from the past single gradually to the integration, miniaturization and the direction of the network rapid development, make the development will be more and more functions, intelligent, will set off a revolution in the field of information. as a complex sensing information science, It integrates the wireless remote sensing technology, distributed processing and wireless signal processing technology, capable of real-time monitoring in the region of the perception of an object acquisition data of interest, such as light and air to ground humidity. After the sensor nodes filter the data, the processing data send to the users. Node localization technology is one of the most important technologies in WSN applications, and it is also the key point discussion of this paper. The coordinates of the node location information is the node sensing data necessary part, the basic premise of monitoring object information acquisition is the node itself can be positioned accurately, or don't know the specific source of data for users is meaningless and worthless.DV-Hop algorithm is a kind of range-free and distributed localization algorithm which is widely used in the future. the location of unknown nodes only considers the average hop distance from its nearest anchor node, which is used to multiply the number of hops to replace the real distance but thus, it will lead to large positioning errors. This paper proposes a high-accuracy localization algorithm TMCD-DV-Hop, which is a improved DV-Hop algorithm of relative high accuracy, based upon threshold mechanism and distance correction and the developed algorithm firstly calculates hop thresholds, and the effect of the other beacon nodes lying outside the nearest anchor node in the local range and global range is considered, thus, best corrected average hop distance has been chosen to estimate the distance, and an estimated coordinate is gained by centroid algorithm after the combinatorial optimization of anchor nodes within the single-hop communicative radius, meanwhile, another estimated coordinate is gained by weighted least-squares method. At last arithmetic mean of two estimated coordinates is considered as orientation coordinate for unknown nodes.Finally, through the Matlab simulation experiments, it will change the communication radius of nodes, the proportion of anchor nodes, the total number of nodes, and several important experimental parameters to simulate all aspects. Through simulation experiment results manifests that in the same network environment, developed TMCD-DV-Hop algorithm could better lower down positioning errors than DV-Hop in the end the positioning accuracy is elevated.