Improving 5G-Advanced Sub-Band Full Duplex Performance with gNB Interference Mitigation

The introduction of sub-band full duplex (SBFD) with simultaneous downlink and uplink transmissions has the potential to improve the uplink performance as compared to traditional static time division duplexing (TDD) with sparse uplink resources. However, SBFD benefits are limited by cross-link interferences caused by the simultaneous uplink and downlink transmissions. This paper proposes to dynamically reduce the 5G base station (gNB) transmission power during SBFD slots to mitigate the gNB self- and gNB-to-gNB-interferences, as well as corresponding link adaptation enhancements to unleash the full potential of such techniques. The SBFD system-level performance is evaluated with different levels of power reduction under varied offered load conditions for urban macro (UMa) and dense urban (DU) environments. Results indicate that for the DU, applying a 10 dB gNB transmit power reduction for SBFD slots leads to a 187% improvement of cell-edge user uplink throughput under high offered load (compared to static TDD). For UMa, at most 4 dB SBFD gNB transmit power reduction is recommended for improving the cell-edge uplink throughput while still ensuring downlink acceptable data rates.