中文摘要：

针对OFDM功率放大器线性化问题，本文采用数字预失真的方法来补偿功率放大器的非线性失真。预失真器采用Voherra序列来逼近，并提出一种重置BFGS算法来训练非线性预失真器。通过设定切换条件，使参数学习在梯度下降法与拟牛顿法之间切换。这既增加了新算法的数值稳定性，又可提高收敛速度。仿真采用数字基带预失真器对OFDM信号的功率放大器进行预失真，结果表明了新算法的高效性。并且，增加数字预失真模块可大大改善OFDM功率放大器的性能。

英文摘要：

For the linearization of orthogonal frequency division multiplexing （OFDM） power amplifiers, a digital predistorter is proposed to compensate for nonlinear distortion in this paper. The pre-distorter is realized by Voherra series, and a restarted BFGS algorithm is proposed for training of the nonlinear pre-distorter. Training of Volterra series can be switched between gradient descend algorithm and quasi Newton algorithm by setting a switching condition. This makes the new algo- rithm much more stable with a fast convergence rate. The pre-distorter is used for OFDM power amplifiers and it high efficiency is proved by simulation results. Moreover, the performance of OFDM power amplifiers is also improved by the predistorter.