Improved APIT Localization Algorithm In Wireless Sensor Networks

Localization is an active area of research in the field of wireless sensor networks. The best solution is provided with the help of range based localization. However, the setup cost is very high for such a system. Range free localization provides an in-budget solution but at the same time, it compromises with the accuracy and increases the localization error. This paper intends to present a cost effective yet more accurate localization solution scheme. This scheme is a range free localization with a blend of APIT, RSSI and PSO algorithm. The algorithm selects and weights the RSSI measurements of the neighboring nodes from the beacon node during beacon exchange to measure the distance based upon the strength. Further, we use PSO along with a cost function to reduce the cost of the coordinates by continuous iterations using position and velocity vectors of the neighboring nodes by finding the coordinates with the global and local least cost. Finally, we use APIT to calculate the coordinates of the unknown or the desired node with the help of the beacon nodes and the neighboring nodes as calculated using PSO. Since the localization is range free, hardware setup cost is minimum and the simulation results shows that the location error is dropped sharply as compared to APIT and combination of APIT with RSSI. As a result, it leads to better accuracy with low cost.