Dynamic Range Normal Bisector Localization Algorithm for Wireless Sensor Networks

Node localization in wireless sensor networks (WSNs) is one of the most critical issues, as many WSN applications depend on precise location of sensor nodes. A number of range-based and range-free localization algorithms have been proposed in last two decades. Range-based schemes attain higher localization accuracy at the cost of extra ranging hardware whereas; range-free schemes are cost effective but show poor localization accuracy. In order to improve the localization accuracy, we have proposed dynamic range normal bisector (DRNB) algorithm which is a distributed range-free localization approach. In DRNB, connectivity between nodes, dynamic ranges of anchor nodes, and principle of normal bisector are used to determine the location of nodes. Each anchor node transmits beacon packets at two different range levels in the network. Each normal node estimates its location by calculating the centre point of the overlapping region of the communication ranges of neighbouring anchors where it lies. Normal bisector technique is used to find the centre point of this overlapping region. Sometimes estimated location of a node may fall out of this overlapping region. To overcome this problem, correction factor has also been proposed. DRNB is an energy efficient algorithm, as it doesn’t require the exchange of information between neighbouring nodes. Analysis and simulation results show that DRNB performs better compared to other existing range-free schemes (e.g. centroid, restricted area based localization and mid-perpendicular algorithm).