Active self-interference cancellation mechanism for full-duplex wireless transceivers

This paper investigates active cancellation techniques for a Full-Duplex transceiver. An auxiliary transmit chain is employed to create the cancellation signal, which is then injected at the receiver RF front-end by using a microstrip coupler. Two methods are proposed to calculate the self-interference cancellation signal. While the first method assumes the transmit chain to be strictly linear, the second one additionally incorporates nonlinear effects, occurring especially in the RF power amplifier. The linear method reports experimentally around 48 dB of self-interference suppression under linear system behavior. Experimental results show also 50 dB of suppression by using the nonlinear method and under nonlinear system behavior, whereas the linear one reports 47 dB of suppression under the same conditions