An Experimental Assessment of 5G Uplink Ranging

Positioning is one of the most promising feature of the latest fifth generation (5G) standard for mobile communications. Positioning functionalities can exploit both the uplink (UL) and downlink (DL) communication direction. While most of the research efforts are devoted to DL positioning, in this work we investigate the problem of UL positioning. Differently from DL, UL communication is severely influenced by the synchronization mechanism used by the Base Station (BS) to control the User Equipment (UE), which primarily relies on timing advance procedure, and whose errors impact directly on the ranging accuracy. By developing a virtualized open-source 5G standalone network, we leverage the UL 5G Sounding Reference Signals (SRSs), broadcasted for channel quality assessments by the UE in a communication session, to perform ranging between the UE and a BS. We analyze the ranging accuracy in terms of measurement error distribution by placing a commercial mobile phone device at different distances from the BS, assessing a range error of 9 m in 95% of the observations.