Over-the-air 5G testbeds were built using USRP software-defined radio (SDR) hardware, X410, running full gNB functionality via the open-source OpenAirInterface (OAI) protocol stack, in 2×2 MIMO configuration with OctoClock-based synchronization across the radio hardware. Rather than relying on a commercial device, the testbed used OAI’s own software-based nrUE as the user equipment, enabling a fully open-source 5G link from base station to user terminal over a live radio-frequency connection. Testing was carried out over physical-layer test mode, to validate the radio link and examin the physical layer perforamnce. This connectivity of USRP hardware with the host PC is examin using QSFP (up to 100 GbE) interface. The testbeds were first validated using a cable-based RF connection to confirm correct system operation before transitioning to full over-the-air testing.
