Efficient algorithm for adjustment of adaptive predistorter in OFDM transmitter

Adaptive predistortion is a technique which is aimed at compensation of nonlinear distortion introduced by a high power amplifier (HPA). This paper presents a simple method of acceleration of the adaptive algorithm of the HPA predistorter. The values of the predistorter complex gain stored in RAM and depending on the input signal amplitude are efficiently modified nor only in the address indicated by the current signal amplitude but also in the whole range of locations around it. The simulation results of the predistorter's adaptation show a visible improvement in the convergence rate as compared with the standard gradient algorithm.