Frequency Domain Non-Linear SIC for BSG/6G Sub-Band Full-Duplex

This work addresses the challenge of non-linear self-interference (SI) cancellation in full-duplex (FD) communications, notably in sub-band full-duplex (SBFD) configurations intended for beyond 5th generation (B5G) and 6th generation (6G) networks. The primary objective is to neutralize the influence of transmitter-side non-linearity on the comprehensive performance of the self-interference canceller (SIC). Although SI emerges at the base station's (BS) receiver in SBFD due to power amplifier (PA) non-linearity, the complexity of time-domain non-linear SIC booms exponentially in environments rich with signal reflection paths. The study presents a low-complexity, frequency-domain non-linear SIC approach that exploits flexible uplink (UL) and downlink (DL) allocation. The proposed SIC evaluates the inclusion of IMD basis in the digital SIC process relative to its impact in terms of the various DL band allocation. By leveraging the frequency domain, the proposed method can seamlessly integrate into OFDM multi-carrier systems through the frequency domain analysis of IMD. The results show that the proposed SIC performs comparably at a low computational cost compared to conventional parallel-Hammerstein (PH) model-based SIC.