A Multipath Mitigation Localization Algorithm Based on MDS for Passive UHF RFID

Traditional localization algorithms are vulnerable in multipath environment for passive UHF RFID tag localization. To improve the localization accuracy, this letter proposes a robust algorithm named residual weighted multidimensional scaling (RWMDS) based on the multipath channel model. The RWMDS algorithm first utilizes reader-to-tag distances derived from received signal phase. To obtain the squared distance matrix required in the algorithm, the inter-tag distances are estimated using a few reference tags by establishing the relationship between inter-tag distance and phase information vectors measurement. Based on the modeling of ranging error in multipath environment, the RWMDS lgorithm can be applied to determine the estimated locations of the tags through a few iterations. Simulation results show that the RWMDS algorithm achieves higher localization accuracy than traditional algorithms in multipath environment.