Research On Non - Ranging Location Algorithm In Wireless Sensor Networks

Wireless sensor network technology combined with the micro control technology and wireless communication technology, is one of the key technologies of the Internet of things in recent years. WSN is composed of a large number of micro sensor node, the nodes will collect the information and sent the information to the monitoring station eventually, to achieve the physical world of human monitoring. Many applications such as forest fire prevention, tracking and monitoring need to know the location information, so the node localization technology is very important. According to whether the distance based, the positioning technology is divided into two general categories: Rang-free and Rang-based algorithm. Rang-free algorithm is widely used because of its simple operation process and low cost. But the positioning accuracy is not high.In order to improve the positioning accuracy and reduce the positioning error, a series of improved algorithm based on Rang-free algorithm is proposed in this paper, and the results are simulated and analyzed by MATLAB. The main research contents and results are as follows:1. Simulates Rang-free algorithm in the new anchor node artificial deployment environment. In the 2, 3-dimensional space, anchor nodes are deployed in a small geometric center. The DV-Hop algorithm and Centroid algorithm were simulated to study the new anchor node deployment patterns at the different communication radius and different number of anchor node compared with the random deployment environment.2. Improved DV-Hop algorithm. By using the least mean square error criterion to modified parameters in the formula for each hop distance of anchor nodes. The best parameter value is found, so that the positioning accuracy can reach the highest in the range of the best positioning parameters. The optimal parameter values of DV-Hop algorithm is simulated in the new anchor node deployment environment, experiment results prove that the algorithm can further improve the positioning accuracy.3. Further improve the positioning accuracy of multi-radius DV-Hop algorithm. On the basis of existing multi-radius algorithm, the calculation for the hop count has been improved. The results further refinement of the hop count. Finally, the algorithm combines the concept of the best parameter values to improve the positioning accuracy. The improved multi-radius algorithm is applied to the new artificial deployment environment, and the positioning accuracy is further improved.4. A 2-dimensional multi-level localization algorithm is proposed. The positioning process divided into multi-level, the first class uses Centroid algorithm based on priority threshold, and the node has been positioned upgraded as an new anchor node in the next class, each class using threshold priority DV hop algorithm, until all nodes complete location estimation.5. By using the best parameter value, the best communication radius and the best threshold, this paper proposes a Rang-free algorithm based on two stages. In the first stage, the Centroid localization algorithm based on the priority threshold is adopted. First, find the best threshold and the best communication radius under different location conditions, and then give priority to the location of the node under the best conditions. In the second stage, the best parameter values are found out by using the DV-Hop algorithm in the best threshold and the best communication radius, and then the improved DV-Hop location algorithm is used to locate the remaining nodes in the best parameter values.Finally, summarize and analyze the advantages and disadvantages of the above methods. We compared a series of improved method with other literature algorithms in Matlab simulation experiments, and show that the improved method can improve the positioning accuracy under certain conditions, without additional hardware costs, calculation, floods times.