OFDM技术以其频谱利用率高，抗干扰能力强等优点而得到了越来越广泛的应用。本文首先系统的总结分析了OFDM的基本原理、特点，并从信号构成的角度说明了OFDM信号对功率放大器非线性敏感的原因，通过对常用的功率放大器模型分析了功放的非线性。 本文的重点是数字预失真技术，在阐述了预失真技术的基本原理后，详细讨论了基于查询表(LUT)和基于多项式的预失真技术。其中在基于查找表预失真技术中详细说明了查找表的形式，地址索引方式以及查找表常采用的方法，在对多项式预失真技术的研究中给出了多项式预失真的原理图及对其原理的详细阐述。接下来对OFDM系统的多项式预失真算法进行了重点研究，首先通过Volterra级数对功放进行建模，改进了模型后得出一种便于计算的功放的简化模型，通过功放模型得出多项式预失真器的模型，然后分别通过对最小均方误差的多项式算法和递归最小二乘的多项式算法的分析比较，最后对递归最小二乘的多项式算法进行了仿真，并对不同的记忆深度下不同的非线性阶数下的仿真结果进行比较和分析。验证了其对功放非线性补偿的有效性，有效的消除了由功率放大器的非线性造成的传输信号的幅度和相位失真，降低了信号邻道干扰，提高了系统频带利用率。 为了进一步改善OFDM数字预失真系统的性能，本文对系统进行改进提出了双功放数字预失真系统，并通过计算机仿真验证了双功放数字预失真系统能够有效的提高系统性能，使输出信号得到更大的增益。

OFDM technology in its high spectrum efficiency, the advantages of anti-interference ability and has been more and more widely. This article summed up the first systematic analysis of the basic principles of OFDM, characteristics, and from the perspective of the signal that constitutes the OFDM signal sensitive to the reasons for non-linear power amplifier, power amplifier through the commonly used model for analysis of the nonlinear amplifier. The focus of this paper is a digital pre-distortion technology, pre-distortion on the basic principles of technology, the detailed discussion based on the look-up table(LUT) and polynomial based pre-distortion technology. One look-up table based pre-distortion technique described in detail in the form look-up table, address look-up table index, and the methods used often, in the polynomial pre-distortion techniques are given in polynomial pre-distortion of the schematic diagram and a detailed description of its principle. Next on the OFDM system polynomial pre-distortion algorithm is focused on, first of all through the Volterra series model of the power amplifier to improve the model for the purpose of computing have come up with a simplified model of the amplifier, through the power amplifier model polynomial pre-distortion device to draw the model, and then through to the minimum mean square error of the polynomial algorithm and recursive least-squares analysis of the polynomial algorithm of comparison, the last of the recursive least-squares polynomial simulation algorithm and the memory of different depths in different order under the non-linear simulation results are compared and analyzed. Amplifier to verify its effectiveness of non-linear compensation, the effective elimination of the non-linear power amplifier caused by the transmission signal of the amplitude and phase distortion, adjacent channel signal to reduce interference and improve the system bandwidth efficiency. In order to improve the OFDM digital pre-distortion performance of the system, the paper proposed to improve the system a dual-power digital pre-distortion system, and through computer simulation to verify a dual-power digital pre-distortion system can effectively improve system performance, so that the output signal of a more a big gain.