Positioning of Devices in LTE Networks. Part 2. Analysis of Base Station Topology Impact on Coordinate Estimation Accuracy

Purpose. In recent decades, the development of positioning services in 4G LTE and 5G NR networks has been actively progressing, necessitating improvements in coordinate estimation accuracy. Earlier, the analysis conducted in the first part demonstrated that signal bandwidth significantly impacts positioning accuracy. This study investigates the influence of base station (BS) topology on coordinate estimation accuracy. The primary indicative factor of BS topology in space is the geometric dilution of precision (DOP) in positioning. The objective of this work is to analyze the influence of the BS topology on the positioning accuracy by the method of difference in the time of arrival of TDOA signals for different scenarios. Methods. As part of the research, a simulation was conducted to calculate the geometric dilution of precision (DOP) for the range-difference method in 4G LTE cellular networks using MATLAB. The mathematical model is based on two approaches: processing absolute ranges and processing pseudoranges. The influence of various BS distribution scenarios on geometric factors (HDOP, VDOP, PDOP, and GDOP) is analyzed. Novelty. The novelty of the research lies in the comprehensive analysis of the impact of base station topology on positioning accuracy, which allows for identifying BS placement schemes considering both horizontal and vertical distribution. This contributes to a deeper understanding of the relationship between network configuration and the quality of coordinate estimation. Results. The study shows that increasing the number of BSs in a given area does not always lead to a reduction in DOP values. As the height of base stations increases, the geometric dilution of precision decreases, which positively affects positioning accuracy. The average DOP value in zones where base stations are located at different heights is lower than in areas with BSs at the same height. The topology of the BS is also determined for estimating the coordinates of vehicles on the road in urban areas. Practical relevance. The results of this work can be used to develop and optimize positioning algorithms in existing and future LTE and 5G NR networks. This has direct applications for improving the quality of navigation, geolocation services, and solving network positioning tasks.