Indoor Positioning in 5G-Advanced: Challenges and Solution Toward Centimeter-Level Accuracy with Carrier Phase Enhancements

• Published in: IEEE wireless communications Vol. 31; no. 4; pp. 268 - 275
• Main Authors: Nikonowicz, Jakub, Mahmood, Aamir, Ashraf, Muhammad Ikram, Bjornson, Emil, Gidlund, Mikael
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 3GPP; 5G mobile communication; Antenna arrays; Antenna measurements; Indoor environments; Industrial applications; Phase measurement; Position measurement; Wavelength measurement
• ISSN: 1536-1284; 1558-0687; 1558-0687
• DOI: 10.1109/MWC.023.2200633

Like robust connectivity, precise positioning is evolving into an innovative component of 5G service offerings for industrial use-cases and verticals with challenging indoor radio environments. Therefore, the 3GPP Rel-16 standard has been a tipping point in specifying critical innovations, followed by enhancements in Rel-17 and Rel-18. In this article, we discuss the 5G positioning framework, measurements, and procedures before shifting the focus to recently identified carrier-phase (CP) measurements in Rel-18 as a complementary measure for time- and angular-based positioning methods. We discuss the associated challenges and potential solutions for exploiting CP, including integer ambiguity, multipath sensitivity, and signaling aspects. Furthermore, we study the ways in which phase-continuous reference signaling can counter noisy phase measurements using realistic simulations to achieve centimeter-level accuracy in indoor factory (InF) scenarios.