On improving the cooperative localization performance for IoT WSNs

The emergence of IoT technology makes the applications of IoT wireless sensor networks (WSNs) attract more attentions, and most of the applications are based on the sensor's location. This paper addresses two main challenges encountered in the localization issue in IoT WSNs, i.e., limited energy in battery-powered sensors, and non-line-of-sight (NLOS) induced errors in harsh environments. We propose a node selection algorithm and an NLOS mitigation algorithm to modify the conventional cooperative localization algorithm for an improved performance. In the node selection algorithm, a node selection criterion is designed to select the most informative reference nodes for each agent, avoiding unnecessary energy consumption. An N-probabilistic hard weight (N-PHW) strategy is developed in the NLOS mitigation algorithm, in which a link condition indicator is set to quantify the quality of each link and NLOS errors are penalized based on this indicator. Numerical results show that by virtue of the proposed node selection algorithm, the energy consumption of the network is significantly reduced. Furthermore, the localization accuracy is improved with the proposed NLOS mitigation algorithm, especially in more severe NLOS environments.