Linearization Approach of Combined Digital Predistortion with Crest Factor Reduction

Abstract

In recent years, digital predistortion (DPD) has been wildly used in the nonlinear compensation of power amplifier. However, saturation distortion which caused by high peak-to-average ratios (PAPR) of the input signal cannot be compensated by DPD perfectly. Therefore, power amplifier should work in certain back-off and results in low efficiency. In this paper, a new method of combined adaptive DPD and crest factor reduction (CFR) is proposed to reduce PAPR, which uses selective mapping (SLM) and companding transform (CT). Besides, an adaptive DPD utilized the LS-LMS algorithm is proposed, which shows stable and fast convergence in the proposed system. Simulation results show that the proposed method can achieve a desirable linearization performance and decrease the predistorted signal's PAPR by 7dB.