FPGA Adaptive Predistorter Based on 64QAM Modulation

This paper presents a predistortion technique compensating for nonlinear distortions caused by HPA (High Power Amplifier) in a QAM (Multilevel Quadrature Modulation) system. Investigations were held both with software and hardware tools. It is confirmed by computer simulation that proposed approach produces a faster convergence speed than traditional computer performed algorithms. Predistortion technique based on programmable logic device is a very attractive from the implementation point of view, because of a low amount of required RAM and rapid convergence from a blind start.