OFDM系统中非线性放大器的改进预失真技术  

An Improved Adaptive Pre-Distortion Technology for Non-Linear Amplifier in OFDM Systems

作　　者：秦川[1] 常天海[1] 

机构地区：[1]华南理工大学电子与信息学院,广州510640

出　　处：《电光与控制》2011年第1期61-65,共5页Electronics Optics & Control

基　　金：国家科技重大专项(2009ZX03006-001);广东省科技重大专项(2009A080207002)

摘　　要：针对OFDM系统中非线性放大器对信号造成的非线性失真影响,采用基于查询表的自适应预失真技术对其进行矫正。在基于最小均方误差算法的经典自适应预失真算法的基础上,采用线性内插算法来更新查询表的内容,从而提高自适应预失真算法的矫正效果;结合OFDM符号的概率分布特性,提出一种增加较大幅度OFDM信号迭代次数的方法,来提高预失真算法的收敛速度。仿真结果表明,改进的预失真算法改善了对非线性功率放大器造成的非线性失真的矫正效果,提高了算法本身的收敛速度。Focusing on the nonlinear distortion caused by nonlinear amplifier in OFDM system,an adaptive pre-distortion technique based on Look Up Table（LUT） was used to rectify it.On the basis of the classic adaptive pre-distortion algorithm based on the least mean square algorithm,linear interpolation algorithm was adopted to update the content of LUT,with the aim of improving the algorithm＇s rectification effect.With consideration of OFDM symbols＇ probability distribution characteristic,one method increasing iteration times of large scale OFDM signal was proposed to improve the algorithm＇s convergence rate.Simulation result demonstrated that the modified pre-distortion algorithm can improve the rectification effect of nonlinear distortion caused by nonlinear power amplifier,and the convergence rate is improved as well.

关 键 词：正交频分复用 非线性放大器 自适应预失真 

分 类 号：V271.4[航空宇航科学与技术—飞行器设计] TN919[电子电信—通信与信息系统]