Topology Search Using Dilution of Precision Criterion for Enhanced 5G Positioning Service Area

Abstract

User Equipment (UE) positioning is an actual topic for research and investigation in Ultra-Dense Networks (UDN) due to transition of 5G and future mobile technologies to mmWave spectrum and narrow beam antenna array wireless communication. Unlike networks of previous generations with two-dimensional (2D) UE localization, 5G UDN applications demand three-dimensional (3D) location estimation with submeter accuracy, especially in so-called enhanced positioning service area. Using range, range difference and bearing processing algorithms with time (TOA), time difference (TDOA) and angle (AOA) of arrival positioning methods respectively usually leads to location accuracy growth with an increase in the number of gNodeB (gNB), gathering primary TOA, TDOA and AOA measurements. However, despite network infrastructure densification, the problem of achieving precise UE positioning still depends on the gNB topology, especially for 3D location case. Well-known criterion for evaluation of sensor geometry on positioning accuracy bounds are so called horizontal (HDOP), vertical (VDOP) and 3D position (PDOP) Dilution of Precision (DOP) factors. Contribution of current research is simulation model, which realizes gNB topology search with optimal in probabilistic sense spatial configuration layout parameters for given HDOP, VDOP or PDOP criterion. Simulation results reveal, that joint TDOA-AOA measurement processing for the case of four gNB leads to satisfactory HDOP, VDOP and PDOP criterions in whole 2D plane of enhanced 5G UDN positioning service area for fixed UE height.