A Measurement-Based In-Band Full-Duplex Spread Spectrum Approach for Analogue-Domain Self-Interference Cancellation

In order to prevent saturation of analogue-to-digital converters in signal receivers and ensure the reception and demodulation of subsequent signals, it is important to suppress the self-interference (SI) signal in the analogue domain in in-band full-duplex systems. To meet the compact and low-power requirements of small satellite platforms, this report proposes a measurement-based digitally-assisted analogue self-interference cancellation (DA-ASIC) approach. This approach introduces additional measurement signals into both the primary and auxiliary transmission channels. It measures the propagation delay difference between the SI signal and the reconstructed SI signal in real time, and compensates for it accordingly. To further enhance performance, a multi-user detection method is proposed to improve measurement precision. The results of a virtual simulation demonstrate that the proposed approach exhibits enhanced performance compared to existing DA-ASIC methods, ultimately achieving 50 dB of analogue-domain SI suppression. Moreover, it is particularly suitable for applications requiring compactness and low power consumption.