The nonlinear distortion of the power amplifier (PA) is studied for Filtered Orthogonal Frequency Division Multiplexing (F-OFDM) systems, which will be adopted in the fifth generation (5G) mobile communication systems. The peak to average power ratio (PAPR) of F-OFDM signal may make the PAs work in the saturation region and result into extremely serious nonlinear saturation distortion, and the nonlinear saturation distortion is usually compensated by predistortion technology. A digital predistortion (DPD) structure is designed to compensate the nonlinear characteristics of the PA in the article. Firstly, repeated iterative clipping revision (RICR) algorithm is used to reduce the PAPR, which makes the working region of PA infinitely close to the saturation region, and as a result, the efficiency is improved. Furthermore, an integrated structure combining crest factor reduction (CFR) and DPD is employed. The experimental results show that the performance of the proposed CFR joint adaptive DPD lowers the PAPR of the predistorted signal by 2dB. The combined CFR & DPD reduces the ACPR of the transmitter by 3dB compared with the unlinearized PA.

针对滤波正交频分复用（F-OFDM）系统研究了功率放大器（PA）的非线性失真，该系统将在第五代（5G）移动通信系统中采用。F-OFDM信号的峰均功率比（PAPR）可能会使PA在饱和区域工作，并导致非常严重的非线性饱和失真，并且通常通过预失真技术来补偿非线性饱和失真。设计了一种数字预失真（DPD）结构来补偿本文中PA的非线性特性。首先，采用重复迭代剪裁修正（RICR）算法来减小PAPR，使PA的工作区域无限接近饱和区域，从而提高了效率。此外，采用结合波峰因数降低（CFR）和DPD的集成结构。实验结果表明，所提出的CFR联合自适应DPD的性能可使预失真信号的PAPR降低2dB。与非线性PA相比，组合的CFR和DPD将发射机的ACPR降低了3dB。