A Cooperative NLoS Identification and Positioning Approach in Wireless Networks

Non-line-of-sight (NLoS) propagation of radio frequency (RF) signal has proven to be challenging for the localization of unknown nodes in wireless networks. In particular, the blockage of RF signal can heavily affect the accuracy of range measurements performed between nodes and in turn may cause the position estimation diverging. This paper analyzes the Cramer-Rao lower bound (CRLB) of cooperative localization in presence of NLoS measurements and proposes a cooperative NLoS identification scheme as well as a cooperative positioning algorithm based on belief propagation. The proposed algorithm is fully distributed and does not need to know the state of NLoS range measurements. Simulation results show that the proposed algorithm is able to detect the state of each range measurement and improve positioning accuracy in several NLoS conditions.