Method and apparatus of frequency domain echo canceller
AssigneeNetLogic Microsystems, Inc.
InventorYehuda Azenkot
Life of this patent
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Abstract
A frequency-domain based echo and NEXT canceller is claimed. The canceller uses log2 encoding to precondition the error signal representing the echo. An improved gradient constraint is applied on at least a portion of a full weight vector in the least-means-square algorithm. The gradient constraint on the portion of the full weight vector and the log2 encoding improves system complexity with less hardware and power consumption than previous technologies.
Claims64
A frequency-domain echo canceller comprising:
- an error processing unit to transform a time-domain (TD) error signal into a frequency-domain (FD) error signal;
- a gradient constraint unit operable to process at least a portion of a full weight vector;
- a least-mean-square (LMS) adaptation unit, coupled with the error processing unit and an output of the gradient constraint unit, to compute filter coefficients;
- a FD multiplier to multiply a FD input signal and the full weight vector to generate a FD output signal;
- and
- an output processing unit to transform the FD output signal to a TD output signal.
A communication system with adaptive error correction comprising:
- an adaptive frequency-domain (FD) canceller with a gradient constraint unit operable to apply gradient constraint on at least a portion of a full weight vector;
- and
- a delay compensation unit to cancel an FD delay from the adaptive FD canceller.
A method to cancel echo in a communication system comprising:
- applying least-mean-square (LMS) adaptation algorithm, via an LMS adaptation unit, to a frequency-domain (FD) error signal to generate a scaled FD gradient vector corresponding to coefficients of the FD error signal;
- applying gradient constraint, via a gradient constraint unit coupled with the LMS adaptation unit, on at least a portion of a full weight vector of the scaled FD gradient vector to generate a FD gradient constraint vector;
- and
- multiplying the FD gradient constraint vector with a FD input signal by a shifting algorithm to generate a FD output signal with cancelled echo.
A frequency-domain echo canceller comprising:
- a gradient constraint unit to process at least a portion of a full weight vector;
- and
- a least-mean-square (LMS) adaptation unit, coupled with the gradient constraint unit, to compute filter coefficients based on the processed full weight vector.
A frequency-domain echo canceller comprising:
- a gradient constraint unit to process at least a portion of a sum of scaled gradient vectors;
- and
- a least-mean-square (LMS) adaptation unit, coupled with the gradient constraint unit, to compute filter coefficients based on the sum of the scaled gradient vectors.
Dependencies are inferred from the claim text.