28 GHz mmWave Multi-Carrier Full-Duplex System and Over-the-Air Verification

Full-duplex (FD) millimeter-wave radios can increase the spectral efficiency and reduce the latency. In order to take an advantage of the FD technology, a self-interference (SI) needs to be suppressed. In this paper, we investigate the characteristics of SI in the 28 GHz band using over-the-air (OTA) measurements. Using our 28 GHz OTA FD platform, we investigate passive isolation with different antenna layouts and beam steering. We also use an intra-band carrier aggregation signal based on the fifth generation NR standard, and propose a nonlinear interference cancellation (NLIC) technique that works on a per-carrier component (CC) basis for multi-carrier systems. To deal with intermodulation distortion, we propose to include inter-CC terms for NLIC and confirm that the proposed FD and NLIC designs provide sufficient self-interference cancellation performance.