An efficient adaptive predistorter for nonlinear high power amplifier in satellite communication

Abstract

This paper presents an efficient adaptive predistortion technique for compensation of linear and nonlinear distortion caused by high-power amplifier with memory in satellite communication channels. The previous adaptive predistortion techniques, based on Volterra series modeling, are not suitable for real-time implementation due to high computational burden and slow convergence rate. In this paper, the memoryless HPA preceded by linear dynamic system is modeled by the Wiener system which is then precompensated by the proposed adaptive predistorter structured by the Hammerstein model. An adaptive algorithm for adjusting the parameters of the predistorter is derived using the stochastic gradient method. The validity of the proposed approach is confirmed via computer simulation by applying it to 16-QAM satellite communication channel where the HPA is preceded by a linear filter.