Adaptive linearization of power amplifier in orthogonal multicarrier schemes

This paper describes an adaptive predistortion system to linearize a memoryless high power amplifier (HPA). The described technique is independent of the modulation format. In the present paper the behaviour of such a predistorter in the presence of orthogonal frequency division multiplexing (OFDM) modulation schemes is analysed. The predistortion scheme uses a digital signal processing microprocessor and memory look-up tables to predistort the baseband drive signal. Simulation results are given where stability of the adaptation algorithm, rate of convergence and effect of quantization are assessed.