From Experiments to Insights: A Journey in 5G New Radio Localization

The 3GPP has recently made the inclusion of positioning services a priority in future generations of cellular networks, thus providing an opportunity for these networks to serve as fertile ground for the emergence of new service-based applications. With the release of 3GPP Release 16 there has been an extensive standardization effort aimed at improving positioning capabilities in 5G networks, particularly in terms of physical layer signals, measurement techniques, and network architecture. Despite these advances, the experimental evaluation of 5G positioning in real-world scenarios is still lagging behind, due to factors such as the slow integration of positioning technologies into open-source 5G frameworks, the complexity of setting up a testbed for 5G positioning with multiple base stations (BSs), and the high cost associated with such a deployment. This article offers a comprehensive review of these factors and provides a state-of-the-art overview of 5G positioning and its support in SDR-based platforms. In addition, we present guidance on the proper setup and configuration of a testbed for SDR-based multi-BS synchronized 5G positioning, the lessons we have learnt in the process, and through a series of time-based real-over-the-air measurements, we demonstrate how localization design choices can be effectively evaluated even with limited-size and low-cost SDR-based testbed.