Circuits and methods for reducing an interference signal that spectrally overlaps a desired signal

A circuit for processing samples of a received in-phase and quadrature (I/Q) domain signal, the received signal including a desired signal and an interference signal that spectrally overlaps the desired signal, the circuit comprising:

• a first interference suppression circuit configured to remove, in the I/Q domain, a first contribution to the interference signal from the samples of the received signal to generate first processed signal samples;
• an amplitude circuit configured to obtain amplitudes and phases of the first processed signal samples;
• a second interference suppression circuit configured to remove, in an amplitude domain, a second contribution to the interference signal from the amplitudes of the first processed signal samples to generate second processed signal samples;
• a signal quality circuit configured to measure a signal quality metric of the second processed signal samples;
• and
• a parameter adaptation circuit coupled to the signal quality circuit and to the first interference suppression circuit and configured to adjust, based on the measured signal quality metric of the second processed signal samples, one or more parameters of the first interference suppression circuit or one or more parameters of the second interference suppression circuit to improve the signal quality metric of the second processed signal samples.

A method for processing samples of a received in-phase and quadrature (I/Q) domain signal, the received signal including a desired signal and an interference signal that spectrally overlaps the desired signal, the method comprising:

• in the I/Q domain, processing the samples of the received signal using a constant modulus algorithm (CMA) to generate first processed signal samples;
• obtaining amplitudes and phases of the first processed signal samples;
• in an amplitude domain, removing a second contribution to the interference signal from the amplitudes of the first processed signal samples using an algorithm to generate second processed signal samples;
• measuring a signal quality metric of the second processed signal samples;
• and based on the measured signal quality metric of the second processed signal samples, adjusting one or more parameters of the CMA or of the algorithm to improve the signal quality metric of the second processed signal samples.

A method for processing samples of a received in-phase and quadrature (I/Q) domain signal, the received signal including a desired signal and one or more interfering signals, the method comprising:

• in the I/Q domain, removing a first contribution to the interference signal from the samples of the received signal using a first algorithm to generate first processed signal samples;
• obtaining amplitudes and phases of the first processed signal samples;
• in an amplitude domain, removing a second contribution to the interference signal from the amplitudes of the first processed signal samples using a second algorithm to generate second processed signal samples;
• measuring a signal quality metric;
• and
• based on the measured signal quality metric adjusting one or more parameters of the first algorithm or of the second algorithm to more effectively suppress the contribution of the one or more interfering signals relative to the desired signal.