Methods and apparatus for adaptive nonlinear coincident interference cancellation

摘要

Methods and apparatus to cancel an interfering signal using an analog cancellation stage followed by a digital cancellation stage. In an exemplary embodiment, the interfering signal is processed to determine modulation type for removal in the analog domain. The digital stage provides further interference reduction in the digital domain.

主权项

1. A system, comprising:
an analog cancellation stage to receive an input signal having a signal of interest and one or more interfering signals of unknown modulation type (MT), comprising:
a first ADC to digitize the input signal;a first signal processing module configured to process the digitized input signal including to detect the presence of the one or more interfering signals and characterize the MT of each of the one or more interfering signals by comparison to a library of MTs for making a non-linear hard decision of modulation type for each of the one or more interfering signals and generating a parameter adjustable MT model and matched filter MT detectors for non-linearly cancelling each of the one or more interfering signals by adjusting the parameters in the MT models to maximize cancellation;a first cancellation signal generator coupled to the first signal processing module and configured to generate a digital first interference cancellation waveform from the parameter-adjusted interferer MT models generated by the first signal processing module;a DAC coupled to the first cancellation signal generator to transform the first interference cancellation signal from the digital domain to the analog domain for cancelling the one or more interfering signals; andan analog removal module coupled to the DAC to subtract the first interference cancellation signal from the input signal and provide an analog first cancellation output signal; a second ADC coupled to the analog removal module to digitize the analog first cancellation output signal; and a digital cancellation stage coupled to an output of the second ADC, the digital cancellation stage comprising:
a second signal processing module configured to process the digital output signal from the second ADC with further MT model-based interference cancellation and to provide feedback to the first signal processing module to optimize the cancellation of the one or more interfering signals;a second cancellation signal generator coupled to the second signal processing module to optimize digital cancellation; anda digital interference removal module coupled to the output of the second ADC and to the second cancellation signal generator module for further removing the interfering signals in the digital domain.