Patent ID: 9036749
Filing Date: 2015-05-19
Classification: H04B,H04L

Abstract:
1. A system for analog self-interference cancellation comprising: a transmit coupler, communicatively coupled to an RF transmit signal of a full-duplex wireless communication system, that samples the RF transmit signal to create a sampled RF transmit signal having an RF carrier frequency; a frequency downconverter, comprising a mixer, a local oscillator, and an IF filter, wherein the frequency downconverter converts, by heterodyning, the sampled RF transmit signal to an IF transmit signal having an IF carrier frequency, wherein the IF carrier frequency is less than the RF carrier frequency; an IF analog self-interference canceller, comprising a signal divider, first and second tunable filters, first and second scalers, first and second delayers, and a signal combiner, wherein the signal divider splits the IF transmit signal into first and second signal paths, the first tunable filter filters the first signal path to form a first IF transmit signal component and the second tunable filter filters the second filter path to form a second IF transmit signal component, the first scaler and first delayer scale and delay the first IF transmit signal component to create a first IF self-interference signal component, the second scaler and second delayer scale and delay the second IF transmit signal component to create a second IF self-interference signal component, and the signal combiner combines the first and second IF self-interference signal components to form an IF self-interference signal; a frequency upconverter comprising a mixer, a local oscillator, and an RF filter, wherein the frequency upconverter converts, by heterodyning, the IF self-interference signal to an RF self-interference signal having the RF carrier frequency; and a receive coupler, communicatively coupled to an RF receive signal of the full-duplex wireless communication system, that combines the RF self-interference signal with the RF receive signal.