Integrated Digital Self-interference Cancellation for Full Duplex MIMO Radios

In this work, we propose integrated linear and nonlinear digital self-interference cancellation (DSIC) for full duplex (FD) multiple-input multiple-output (MIMO) radios, where nonlinear DSIC is applied to the residual of the linear DSIC over all streams in the MIMO system. As nonlinear DSIC techniques, random Fourier features transformation with least mean squares algorithm and memory polynomial model are considered. Our FD MIMO set-up consists only of two identical monostatic FD antennas, a WARP v3 board, and an add-on transceiver board. Experimental results show that, with the proposed integrated solution, the total cancellation performance of the FD MIMO system is enhanced by up to 6 dB per stream as compared to linear only DSIC.