Cross-link Interference Handling of 5G with Subband Non-overlapping Full Duplex

Subband non-overlapping full duplex (SBFD) simultaneously receives uplink (UL) and transmits downlink (DL) signals on the same time division duplex (TDD) carrier but on different frequency resources, which improves UL coverage and throughput. However, these benefits are damaged greatly due to the severe inter-SB cell-to-cell cross-link interference (CLI). Besides, inter-SB cell-to-cell CLI might cause UL communication blocking with a high probability. To cope with this challenge, the performance of coordinated beamforming (CBF) and minimum mean square error (MMSE)-interference rejection combining (IRC) on inter-SB CLI suppression is studied. Firstly, the characteristics and model of inter-SB CLI are analyzed in SBFD scenario. Then, MMSE-IRC and detailed CBF schemes are proposed to reduce inter-SB CLI. To evaluate the proposed schemes, system-level simulation is provided. In the simulation, CBF could suppress inter-SB CLI by 20 dB and avoid UL blocking issue. Moreover, MMSE-IRC receiver improves the UL coverage by 4.85 dB when compared with legacy TDD.