A novel predistorter based on MPSO for power amplifier linearization

摘要

Power amplifier is an essential component in every wireless communication system, but exhibits nonlinearity. A high power amplifier gets saturated, when the amplitude or power of the input signal is very large. Nonlinearity in power amplifier is due to the combined effect of amplitude distortion, phase distortion and memory effect. By using power amplifier linearization method, efficiency of the power amplifier can be improved without affecting its linearity. In this work an efficient predistorter is implemented for compensating distortions caused by high power amplifiers which shows true output saturation characteristics. Wiener model is used for modeling the power amplifier. The wiener power amplifier model parameter is estimated using particle swarm optimization (PSO) and Modified PSO (MPSO). Then the predistorter is designed using the estimated Wiener HPA model parameters. The predistorter is implemented by using Hammerstein model. The combined performance of predistorter and power amplifier was evaluated.