Iterative path-loss exponent estimation-based positioning scheme in WSNs

In wireless sensor networks, the positioning scheme using the received signal strength (RSS) has been widely considered due to its simplicity. Appropriate estimation of path-loss exponent (PLE) between a sensor node and an anchor node plays a key role in reducing position error in this RSS-based positioning. In the conventional researches, a sensor node directly uses the PLEs given by its neighboring anchor nodes, e.g., its nearest anchor node, to calculate its position. However, the PLE between a sensor node and an anchor node is usually different from those given by the anchor nodes, and accordingly results in the distance error in sensor node´s positioning. In this paper, we propose the method how a sensor node estimates PLEs from the anchor nodes of interest by itself and calculates its position based on these self-estimated PLEs. In the proposed scheme, a sensor node recalculates PLEs depending on the estimated distances between itself and anchor nodes, and reproduces its position based on the recalculated PLEs. Through simulations, we show that our proposed positioning scheme outperforms the traditional scheme in terms of position error.