US Patent 10230422 Systems and methods for modified frequency-isolation self-interference cancellation

A system for frequency isolation modified self-interference cancellation includes a transmit coupler, that samples an RF transmit signal; an RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal; a receive coupler that combines the RF self-interference cancellation signal with the RF receive signal to form a reduced-interference receive signal; and a frequency shifter that frequency shifts only one of the RF transmit signal and the reduced-interference receive signal.