Investigation on Positioning Techniques for Indoor Office Scenario

Sammanfattning: This master thesis aims to investigate downlink positioning techniques and improve fifth-generation (5G) cellular positioning performance in the indoor office scenario. In the thesis work, we target in the indoor office scenario because it is a typical deployment scenario standardized in 3GPP release 16. To analyze the positioning techniques, we develop a simulator in MATLAB. In the simulator, the channel model, environment geometry, positioning reference signals, and frame structure are all aligned with 3GPP release 16. To ensure the alignment is proper, we compare our simulation results with the results of other companies under the same conditions. Our research mainly focuses on downlink time difference of arrival and downlink angle of departure methods. For the time difference of arrival method, we implement various techniques, such as time-based beam selection. For the angle of departure method, we apply a first delay path based angle of departure detection. The simulation results show that our receiver can obtain a more accurate measurement than the legacy methods. Furthermore, we investigate various least squares and maximum likelihood localization algorithms. To mitigate the non line-of-sight effects, we propose an algorithm which combines the residual weighting algorithm and residual testing method. The simulation results show that this algorithm outperforms the residual weighting algorithm in the indoor office environment. Besides, based on the maximum likelihood approach, we combine the downlink time difference of arrival technique and downlink angle of departure technique, which improves the positioning accuracy. Specifically, the positioning performance can achieve 2.9 meters and 1.1 meters of error for 80% of user equipment in the indoor mixed office and indoor open office, respectively.