Patent ID: 7542518

Claim:
A polynomial predistortion apparatus for compensating for a nonlinear distortion characteristic of a power amplifier, comprising; an adaptation controller for determining polynomial coefficients by calculating an inverse nonlinear distortion characteristic of the power amplifier, and calculating complex predistortion gains for all possible amplitudes of an input signal using the determined polynomial coefficients; and a predistorter for receiving an input signal which is a combination of complex-modulated previous baseband input signal samples and current input signal samples, predistorting the input signal using the complex predistortion gains output from the adaptation controller, and outputting the predistorted input signal to the power amplifier, wherein the predistorter comprises: a first complex multiplier for multiplying an in-phase signal component and a quadrature-phase signal component of a current input signal by complex predistortion gains which ate accessed from the look-up table according to amplitudes of the current input signal; at least one second complex multiplier for multiplying an in-phase signal component and a quadrature-phase signal component of a previous input signal by complex predistortion gains which are accessed from the look-up table according to amplitudes of the previous input signal; and a summer for summing outputs of the first and second complex multipliers to generate a predistorted signal, and outputting the predistorted signal to the power amplifier.