Study Of Node Localization Technology In Randomly-deployed Wirelss Sensor Networks

The localization issue is one of the basic researches in Wireless Sensor Networks(WSNs). In WSNs, it is important to make sure that where the event happened. Manyscholars have carried out a great deal of research on WSNs’ localization technology andhave proposed a lot localization algorithm. In some complicated and changeableenvironments where people could not reach, the only method to deploy WSNs is todistribute sensors random. Such WSNs have the characteristics of irregular shape,non-uniform distribution and having barriers etc. which cause existing localizationtechnologies being limited in practical applications. According to the characteristics ofrandomly-deployed WSNs, this paper carries out some innovation work as follows:Firstly, this paper proposes an adaptive density-sensing localization method. It usesmobile beacon technology. Mobile beacon node makes dynamic decisions both on thedirection of movement and mobile length of next step through perceiving the density andthe localization need of the nodes around. To solve the problem of energy costs and toprevent beacons from being in line, this paper uses two beacons whose positions areimmobile relatively to each other to localize collaboratively, and they move as spiral pathdynamically. The experiments’ results show that this method can adapt to all kinds ofnon-uniform WSNs with different densities and shapes, besides, it has high localizationcoverage rate and low beacon collinear degree.Secondly, according to the characteristics of border nodes that they have less neighbornodes which are distributed leaning to inside network, this paper proposes a series ofmethods. First we identify border nodes in WSNs, and then locate the border nodes whichdo not have enough connectivity using2-hop neighbors assisted method to improve thelocalization rate of border nodes. At last the accuracy assessment and correction to bordernodes are made. The experiments’ results show that these methods can improve localizationcoverage rate and localization accuracy to some extent.