After 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. In this direction, 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 elaborate on the 5G positioning framework, measurements, and procedures before shifting the focus mainly 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 how phase-continuous reference signaling can counter noisy phase measurements using realistic simulations to achieve centimeter-level accuracy in indoor factory (InF) scenarios.

翻译：在稳健连接之后，精确定位正成为面向工业用例及具有挑战性室内无线电环境的垂直行业的5G服务创新组成部分。在此方向上，3GPP Rel-16标准在指定关键创新方面具有里程碑意义，随后Rel-17和Rel-18进一步增强了功能。本文详细阐述了5G定位框架、测量与流程，随后重点聚焦于Rel-18中最近确定的载波相位测量技术，将其作为基于时间和角度定位方法的补充手段。我们讨论了利用载波相位所面临的挑战及潜在解决方案，包括整周模糊度、多径敏感性和信令问题。此外，我们通过真实场景仿真研究了相位连续参考信令如何应对噪声相位测量，以在室内工厂场景中实现厘米级精度。