Convex Programming-based Research On Localization Algorithm Of Wireless Sensor Networks

Wireless Sensor Networks(WSN)is a cellular system which integrates data collection,integration,processing,transmission and other functions.As the basis and an important component of the Internet of things,it ranged over many fields such as software and hardware technology,computer network and communication technology.In the application of wireless sensor networks,such as military,medical treatment,environmental monitoring,forest fire,space exploration and so on,the precise localization of data usually needs determining while data are collected.Therefore,node localization technology plays a very important and indispensable role in wireless sensor networks.In the actual environment,the problems of irregular network topology,complex dissemination environment and uneven node deployment are often encountered,which demands greater from the performance of the localization algorithm.In this paper,the existing localization algorithms are studied and analyzed,and the shortcomings of the existing algorithms are considered and distinguished.The convex programming location algorithm is studied in detail,and improved algorithms are proposed.The main work of this paper is as follows:(1)The current research status of convex programming localization algorithms is analyzed,and the shortcomings of convex programming location algorithms are pointed out.The basic principle,algorithm process and existing problems of classical RSSI-Convex algorithm is analyzed.(2)By analyzing RSSI-Convex algorithm,we found that the condition of RSSI was utilized inadequately,so an improved algorithm based on the circle formed by RSSI is proposed after demonstration.The improvements of the original algorithm are:in view of the fact that there is only one beacon node in the communication radius of unknown node,it's no longer the only way to take place unknown node coordinates with the beacon node coordinates.The improved algorithm uses the transformation of reference system in physics to reduce the unknown node of unknown regions;In the situation of there being more than one beacon nodes in the communication radius of unknown node,unknown region of unknown node determined by RSSI-Convex can be further reduced by the use of circle formed by RSSI,and thus achieve the objective of improving the positioning accuracy.The experimental results showed that the localization accuracy of the nodes can be improved under the condition of full utilization of RSSI.(3)An improved algorithm is proposed on the basis of RSSI-Convex convex programming algorithm and a large number of references.The RSSI-Convex algorithm is audaciously improved by introducing the concept of variable angle:Variable angles are used to further reduce unknown regions of unknown nodes by substitution circle sector for circle,to achieve the objective of improving the positioning accuracy;the probability average idea of unknown node reasonable limit line in the angle bisector,making the process of solving the unknown node further simplified.Experimental results showed that the improved algorithm has higher positioning accuracy than the original algorithm,and can better improve the existing problems.Compared above two improved algorithm,we found:the improved algorithm based on dynamic angle division,which its curve is more gentle,can satisfy fields with low precision of beacon nodes and high precision requirements,such as military,medical treatment and so on.Another improved algorithm based on RSSI don't increase the cost,provide higher precision,can obtained higher accuracy in environmental monitoring,forest fires and other sources of information.