基于多项式与查找表的预失真技术研究

Study on Pre-distortion Technique Based on Polynomial and Look-up Table

为补偿功率放大器固有的非线性,提出了一种新型的预失真器。该预失真器结合查找表和多项式两种常用的预失真方法实现,在查找表中存储分段低阶多项式系数,根据输入信号的幅度查表得到相应的多项式系数对输入信号进行预失真处理。仿真结果表明,该预失真器对互调失真(IMD)的改善优于多项式预失真器,能有效改善信号因功放非线性失真而导致的信号星座图扭曲及频谱再生,提高通信系统的性能。

In order to overcome the inherent nonlinearity of power amplifier （PA）, a novel predistorter is proposed. The predistorter joints look-up table and polynomial predistortion methods. The searched polynomial coefficient, which indexed by the amplitude of input signal, is used to predistort the input signal. The simulation results show that the proposed predistorter performs much better than the polynomial predistorter on IMD and improve the signal misshapen constellation shape and spectral spreading of signal because of nonlinearity of PA, then, the performance of communication system is increased.