Digitally-Augmented Wideband Self-Interference Cancellation In Full-Duplex Transceiver

This paper presents a novel digitally-augmented analog self-interference (SI) cancellation (DASIC) scheme in a full-duplex transceiver, supporting simultaneous transmission and reception. A linear behavioral model is designed to characterize and reconstruct a multipath SI propagation channel in the digital domain. An auxiliary transmit chain is deployed to transmit the reconstructed signal and perform analog SI cancellation at the low-noise amplifier (LNA) input. The cancellation algorithm is developed on a Zynq Ultrascale+ RFSoC FPGA evaluation kit as part of the experimental hardware testbed. Extensive measurements demonstrate up to 38 dB cancellation of the TX passband leakage signal. This provides an improved wideband analog SI cancellation performance for a cancellation bandwidth of 400 MHz. To the best of the author's knowledge, this is the first-ever hardware realization of a digitally-augmented analog cancellation of such wide bandwidth.