Linearization with memory compensation

A method for compensating for linearizing a power amplifier while compensating for memory effects of the power amplifier, comprising:

• generating a first polynomial using powers of an envelope for an RF input signal to the power amplifier;
• generating additional polynomials using delayed powers of the envelope of the RF input signal, the delayed powers being delayed according to an adaptive time constant to compensate for a memory effect of the power amplifier;
• adding the polynomials to provide a pre-distortion signal for pre-distorting the RF input signal into a pre-distorted RF input signal for driving the power amplifier such that a non-linearity in the power amplifier is reduced with respect to an amplified RF output signal from the power amplifier;
• delaying the pre-distortion signal according to multiples of the adaptive time constant to provide delayed versions of the pre-distortion signal;
• and
• adding the delayed versions of the pre-distortion signal with the polynomials to produce the pre-distortion signal.

A polynomial generator and memory compensator module, comprising:

• a first means for generating current and delayed versions of the envelope for an RF input signal and for generating current and delayed versions of the square of the envelope,
• a second means for generating polynomials using the current and delayed versions of the envelope, each polynomial being weighted according to pre-distortion weights;
• a third means for adding the polynomials to provide a pre-distortion signal for pre-distorting the RF input signal to provide a pre-distorted RF input signal such that a power amplifier amplifying the pre-distorted RF input signal provides an amplified RF output signal that reduces a non-linearity of the power amplifier;
• and
• a fourth means for generating delayed versions of the output signal, wherein the adder further adds the delayed versions of the output signal to the polynomials to provide the pre-distortion signal, and wherein the polynomial generator module and memory compensator module is integrated within a pre-distorter system including a performance monitor operable to compare a version of the amplified RF output signal to a delayed version of the RF input signal to provide an error signal, and wherein the performance monitor is configured to iteratively adapt the coefficients based upon a gradient of a cost function, the cost function being a function of the error signal.