| 摘要: |
| 提出了一种由单形规范线性分段(SCPWL)函数与记忆多项式级联的数字预失真器，并给出了复数域两步最小二乘参数辨识算法。不同于以往一种预失真器适用一种功放模型的情况，所提的预失真算法利用SCPWL函数的分段特性以及记忆多项式的非线性记忆特性，在完成参数辨识的同时自动地调整结构，可适用于传统以及强非线性新型功放模型的线性化补偿。将所提预失真器分别应用于传统记忆多项式、两箱模型以及新型包络跟踪功放。经过计算机仿真，功放输出的幅频特性和频谱曲线表明所提预失真器能够有效地补偿多种功放的非线性特性。算法仿真比较结果也表明，针对包络跟踪功放，所提复数两步最小二乘算法的邻道泄漏比(ACLR)可改善约35 dB，性能优于最小均方(LMS)类算法约30 dB。 |
| 关键词: 数字预失真 级联两箱模型 SCPWL函数 记忆多项式 包络跟踪 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目(61701422);福建省自然科学基金资助项目(2015J01670);厦门市科技计划项目(3502Z20153017) |
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| A cascaded versatile digital predistorter and its identification algorithm |
| YUAN Jiangnan,TANG Jun,YIN Jinwang |
| () |
| Abstract: |
| A digital predistorter of cascaded simplicial canonical piecewise linear function(SCPWL) and memory polynomial is proposed,and the complex field two-step least square(TSLS) parameter identification algorithm is presented as well. Different from the case that one type of predistorter adapts to specially appointed amplifier,the proposed predistortion algorithm is able to adjust its structure during the parameter identification period automatically to accommodate multiple amplifier models by using the piecewise features of SCPWL function and the nonlinear memory characteristics of memory polynomial. The proposed predistorter algorithm has been used to compensate for traditional polynomial,two-box model and state-of-art envelope tracking amplifiers. Amplitude-frequency and spectrum curves of computer simulations show that the proposed predistorter can adaptively compensate for all these amplifiers’ nonlinear characteristics. Algorithm comparison also shows that,in case of envelope tracking amplifiers,the adjacent channel leakage ratio(ACLR) performance of TSLS algorithm can be improved over 35 dB approximately,superior to that of LMS class algorithms about 30 dB. |
| Key words: digital predistortion cascaded two box model scpwl function memory polynomial envelope tracking |
《电讯技术》编辑部 