Quadrature ampliltude modulation has high spectral efficiency but is highly sensitive to power amplifier

nonlinearities. It is shown that an adaptive predistorter usig polynomial amplitude and phase

predistortion functions can be used to linearize the power amplifier. Tie recursive least square algonrthm

is employed in an estimator which uses demodulated signals to estimate the required predistortion.

Computer simulation results are provided and these results show that fast convergence and high spectm

improvement can be obtained using the proposed linearization method. The results are significantly

better than those reported before for other linearization techniques.