A Novel Generalized Parallel Two-Box Structure for Behavior Modeling and Digital Predistortion of RF Power Amplifiers at LTE Applications

摘要

This paper presents a generalized parallel two-box structure that is proposed for modeling and digital predistortion of power amplifiers and wireless transmitters exhibiting memory effects. The proposed predistortion scheme consists of two separable boxes; the first is utilized to model the static behavior of the power amplifier, while the second is proposed to consider the memory effect and nonlinear distortion of the power amplifier. The coefficients of the proposed model are identified by applying an indirect learning structure and a least square method. The validation of the proposed model is carried out using the simulation of the power amplifier and the digital predistortion excited by a 64QAM signal in the advanced design system software. According to the simulation results, the criterion of adjacent channel power ratio reduced by about 16 dB. The simulation results reveal an adjacent channel power ratio of almost - 48 dB. Indeed, the proposed model leads to a better performance in terms of spectral regrowth in comparison with the memory polynomial model, and it also reduces the number of coefficients by approximately 22%. This proposed model enables a more accurate modeling of nonlinear distortion and memory effects compared to previous linearization methods.