宽带多载波微波光链路的自适应非迭代线性化技术  

Adaptive Non-Iterative Linearization Technique for Broadband Multi-Carrier Microwave Photonic Link

作　　者：卢冰 陈康 侯维刚 白一凡 张佳昕 郭磊[1,2] Lu Bing;Chen Kang;Hou Weigang;Bai Yifan;Zhang Jiaxin;Guo Lei(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Institute of Intelligent Communication and Network Security,Chongqing University of Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065 [2]重庆邮电大学智能通信与网络安全研究院,重庆400065

出　　处：《光学学报》2024年第12期197-205,共9页Acta Optica Sinica

基　　金：国家自然科学基金(62001072,62222103);国家自然科学基金区域联合基金(U22A2018);重庆市自然科学基金(CSTB2022NSCQ-MSX133,CSTC2021JCYJ-BSHX0206);重庆市教委创新研究群体项目(CXQT21019)。

摘　　要：本文针对宽带多载波微波光子链路(MPL)中产生的带内三阶交调失真(IMD3)和带外互调失真(XMD),给出了相应的非线性失真模型,然后基于失真模型中的XMD和IMD3信号与基频信号符号相反的特性来获取具有闭式解的代价函数,从而在快速自适应获取最优线性化系数的同时完成对XMD和IMD3的补偿。与现有的XMD和IMD3补偿方法相比,该方法无需系统和信号的先验参数,无需复杂的训练和迭代优化过程,实用性更好。仿真结果表明,在基于马赫-曾德尔调制器的MPL中传输多音信号时,链路中产生的XMD和IMD3分别被抑制了35 dB和29 dB以上;此外,当传输多载波正交频分复用信号时,信号的误差矢量幅值从8.1%优化到了2.2%。Objective Microwave photonic technology has an important potential in future high-speed microwave/millimeter-wave communication systems due to its large bandwidth,low loss,and immunity to electromagnetic interference.However,due to the inherent cosine response of the electro-optic modulators,the output signals of the broadband multi-carrier microwave photonic link(MPL)will suffer from nonlinear distortions,mainly including harmonic distortions(HD),crossmodulation distortion(XMD),and third-order intermodulation distortion(IMD3).Since HD can be filtered out by a suitable filter,the XMD and IMD3 are the main factors limiting the system performance.We build a nonlinear distortion model for in-band third-order IMD3 and out-of-band XMD compensation of a broadband MPL.Despite various optical and electrical methods are proposed to compensate for the IMD3,few methods can quickly compensate for both XMD and IMD3 of a broadband MPL spontaneously.Thus,a nonlinear distortion model is presented for compensating the in-band IMD3 and out-of-band XMD in the wideband MPL.This method does not require priori parameters of the system and signals,and a complicated training and iterative optimization process,which is more practical.Methods We provide a nonlinear distortion model for a broadband multi-carrier MPL.Firstly,due to large frequency differences between the HD signal and the fundamental frequency signal,the HD signal can be easily filtered by a digital filter.Then,the XMD and IMD3 signals are extracted,which are the opposite sign to the fundamental frequency signal.Thus,it is easy to obtain that the cubic power of the XMD and IMD3 signals is also the opposite sign of the fundamental frequency signal.Based on the characteristic,a cost function with a closed-form solution can be constructed,where an optimal linearization coefficient is obtained quickly and adaptively.Finally,this optimal linearization coefficient is introduced to compensate the XMD and IMD3 simultaneously in the digital domain.Results and Discussions Simulation

关 键 词：微波光子学 数字线性化 三阶交调失真 互调失真 

分 类 号：TN911.7[电子电信—通信与信息系统]