Abstract:
Obtaining location information of sensor nodes in Wireless Sensor Network (WSN) for indoor environment is a daunting task as the indoor environment suffers from the absence of direct line of sight, multipath fading, shadowing and signal degradation due to presence of furniture and walls. Traditionally, sensor nodes in WSN use omnidirectional antennas and localization using RSSI fails to detect the accurate position of sensor nodes. Other techniques such as Time of Arrival (ToA), Time Difference of Arrival (TDOA), Angle of Arrival (AoA) and Triangulation reduces localization error, but makes the system more complex. All these techniques require expensive hardware and high energy making them inappropriate for WSN. Hence, in this paper, we propose a simple energy efficient RSSI based indoor localization mechanism using a single anchor node with sector antennas. This simple localization mechanism estimates the distance of the target node pertaining to a particular sector. We have also developed an interference avoidance mechanism in order to obtain an accurate distance estimation. Proposed RSSI based localization model has been tested, evaluated and calibrated by deploying 16 Micaz target nodes with omnidirectional antennas and one Micaz anchor node with four sector antennas in an indoor environment. From the extensive round of experiments conducted, we obtained mean localization error of 0.4913m.