Self-Interference Channel Measurements Utilizing mmWave Phased Arrays for Full-Duplex IAB Scenario

This paper reports the measurement results of self-interference radio channels in a street-parallel lamppost scenario. This scenario is an envisioned deployment scenario for the integrated-access-and-backhaul use case. To emulate the access and backhaul air interfaces of an integrated-access-and-backhaul node, we perform measurements by means of two 8 × 8 phased arrays and a 20-dBi standard horn antenna. Additionally, the measurement setup comprised a vector network analyzer that was used to sweep 2 GHz bandwidth centered around 27.5 GHz carrier frequency. Each phased array emitted 50 dBm equivalent isotropically radiated power and swept an azimuth 120° plane by 21 beams (6° beam spatial resolution). The measured self-interference channel power-delay profiles have revealed the dependency of the backscatter self-interference channel with respect to beamforming direction - in azimuth and elevation - between the access and the backhaul air interfaces. Furthermore, we experimentally observed from measurements that the phased array beamforming drastically impacts the self-interference radio channel mutual-coupling-based segment.