Methods and systems for estimation and mitigation of swept-tone interferers

An apparatus for mitigating an effect of a swept-tone interferer from a composite signal comprising a signal of interest and the swept-tone interferer, the apparatus comprising:

• a receiver configured to receive the composite signal over an observation bandwidth, wherein the swept-tone interferer is modeled as a magnitude-periodic signal, wherein the magnitude-periodic signal comprises a plurality of phase-rotated pulses, and wherein each of the plurality of phase-rotated pulses comprises a common pulse shape and a distinct phase rotation;
• a squaring module configured to compute an energy signal based on the composite signal;
• a period estimation module configured to estimate a period of the magnitude-periodic signal based on the energy signal;
• a first pulse estimation module configured to generate an initial estimate of the common pulse shape based on the period and energy detection of the energy signal, wherein a length of the initial estimate of the common pulse shape is equal to the period;
• a phase estimation module configured to estimate a plurality of phase estimates based on a plurality of epochs and the initial estimate of the common pulse shape, wherein the plurality of epochs corresponds to non-overlapping, contiguous segments of the composite signal, wherein a length of each of the plurality of epochs is equal to the period, wherein each of the plurality of epochs comprises the common pulse shape, and wherein each of the plurality of phase estimates is generated for each of the plurality of epochs;
• a second pulse estimation module configured to generate a plurality of phase de-rotated pulse estimates, wherein each of the plurality of phase de-rotated pulse estimates is based on each of the plurality of epochs and each of the plurality of phase estimates;
• an averaging module configured to compute a weighted average the plurality of phase de-rotated pulse estimates to generate a final estimate of the common pulse shape;
• an interference estimation module configured to generate an estimate of the swept-tone interferer based on the final estimate of the common pulse shape and the plurality of phase estimates;
• and
• a summer configured to subtract the estimate of the swept-tone interferer from the composite signal to generate an interference-mitigated signal of interest.

A non-transitory tangible computer-readable medium embodying program code executable by a computing system, the program code comprising:

• program code for receiving a composite signal over an observation bandwidth, wherein the composite signal comprises a signal of interest and a swept-tone interferer;
• program code for modeling the swept-tone interferer over the observation bandwidth as a magnitude-periodic signal, wherein the magnitude-periodic signal comprises a plurality of phase-rotated pulses, and wherein each of the plurality of phase-rotated pulses comprises a common pulse shape and a distinct phase rotation;
• program code for computing an energy signal based on the composite signal;
• program code for estimating a period of the magnitude-periodic signal based on the energy signal;
• program code for generating an initial estimate of the common pulse shape based on the period and energy detection of the energy signal, wherein a length of the initial estimate of the common pulse shape is equal to the period;
• program code for estimating a plurality of phase estimates based on a plurality of epochs and the initial estimate of the common pulse shape, wherein the plurality of epochs corresponds to non-overlapping, contiguous segments of the composite signal, wherein a length of each of the plurality of epochs is equal to the period, wherein each of the plurality of epochs comprises the common pulse shape, and wherein each of the plurality of phase estimates is generated for each of the plurality of epochs;
• program code for generating a plurality of phase de-rotated pulse estimates, wherein each of the plurality of phase de-rotated pulse estimates is based on each of the plurality of epochs and each of the plurality of phase estimates;
• program code for computing a weighted average of the plurality of phase de-rotated pulse estimates to generate a final estimate of the common pulse shape;
• and
• program code for generating an estimate of the swept-tone interferer based on the final estimate of the common pulse shape and the plurality of phase estimates.