An Improved 3D Indoor Positioning Study with Ray Tracing Modeling for 6G Systems

The integration of communication and perception is one of the developing trends of the communication system. The severe multipath effect is one of the biggest challenges of indoor positioning. Most existing studies are based on 2D models, which avoid multipath effects and require multiple Base Stations (BSs) to coordinate for positioning. In this paper, we build a 3D indoor multipath signal model and achieve 3D indoor positioning with a single BS by making full use of multipath channels. The Angles of Arrival (AoAs) of the multipath signals are estimated by two mutually perpendicular Uniform Linear Array (ULA) antennas. And the Time of Arrival (ToAs) are estimated by the pilot subcarriers of the OFDM signal. Then, we propose an improved matching algorithm, which matches the AoAs and ToA of each signal accurately. We get the linear equations of multipath channels with ray tracing modeling to achieve 3D indoor positioning. An angle compensation algorithm is proposed by evaluating the probability weight of each multipath AoA and compensating the AoA according to the weights. The simulation results show that the positioning accuracy of the proposed algorithm is within 0.64 m in 90% of the cases, and within 0.25 m in 50% of the cases.