5G NR Positioning with OpenAirInterface: Tools and Methodologies
Rakesh Mundlamuri, Rajeev Gangula, Florian Kaltenberger, Raymond Knopp
TL;DR
This work addresses the need for experimental validation of 5G NR positioning techniques by providing a practical OpenAirInterface (OAI) framework for positioning experiments and an RTT-based ranging prototype. It delivers essential OAI functions for positioning signals (PRACH, PRS, SRS), a detailed fixed-point baseband representation and dBFS scaling, and a T_tracer data-extraction workflow to enable reproducible measurements. The RTT prototype demonstrates a low-overhead, multi-measurement ranging approach in a controlled LoS setup, with a public dataset (rtt_dataset) containing SRS channel estimates, impulse responses, and noise references. Together, these contributions bridge the gap between protocol-level positioning concepts and real-world prototyping, supporting researchers in validating and improving 5G NR positioning methods on open-source hardware and software stacks; the RTT relation follows $\hat{d} = \frac{p c}{2 f_s}$ for peak-based range estimation and extensions using coherent averaging as described in Mundlamuri2024.
Abstract
The fifth-generation new radio (5G NR) technology is expected to provide precise and reliable positioning capabilities along with high data rates. The Third Generation Partnership Project (3GPP) has started introducing positioning techniques from Release-16 based on time, angle, and signal strength using reference signals. However, validating these techniques with experimental prototypes is crucial before successful real-world deployment. This work provides useful tools and implementation details that are required in performing 5G positioning experiments with OpenAirInterface (OAI). As an example use case, we present an round trip time (RTT) estimation test-bed based on OAI and discusses the real-word experiment and measurement process.