Positioning: Rel-17/18 enhancements, cm-level accuracy

NR Positioning Methods and Accuracy Evolution

NR positioning has evolved rapidly across releases. Rel-16 introduced baseline methods: DL-TDOA using Positioning Reference Signals, UL-TDOA using SRS, multi-RTT combining DL and UL measurements, and DL-AoD and UL-AoA angle-based methods. Rel-17 enhanced these with wider PRS bandwidth (up to 400 MHz in FR1), longer PRS sequences for improved NLOS resilience, and on-demand PRS to reduce always-on overhead. Accuracy improved from 3-10 meters in Rel-16 to sub-meter in Rel-17 for commercial indoor environments. Rel-18 pushed further with carrier phase positioning targeting centimeter-level…