Joint Localization and Environment Sensing by Harnessing NLOS Components in mmWave Communication Systems

Integrated sensing and communication (ISAC) is considered as a promising technique to provide mutually enhanced performance in future millimeter-wave communication systems. However, the non-line-of-sight (NLOS) components are usually treated as interference for radio-based localization in the existing literature, although they are proved to capture certain information about the radio propagation environment. In this study, we focus on the simultaneous estimation of location and velocity for user equipment (UE) as well as locations for scatterers by harnessing NLOS path measurements. Specifically, we integrate LOS and NLOS path measurements into a onestage linear weighted least squares estimator, where NLOS paths contribute to the estimation of scatterers (environment sensing), and also assist the localization of UE. We have also proved that the estimator is capable of localization in terrible situations when all the LOS paths are blocked. Comprehensive simulation results show that the estimator can attain the Cramer-Rao lower bound under small noise levels and outperform the state-of-the-art methods.