基于非线性编码的叠加概率整形20QAM星座方案  

Superposed probabilistic shaping 20QAM constellation scheme based on nonlinear coding

作　　者：卢美霞 郭心悦[1] LU Meixia;GUO Xinyue(School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093

出　　处：《光通信技术》2024年第2期56-61,共6页Optical Communication Technology

摘　　要：针对多输入多输出可见光通信系统计算复杂度高、相邻星座点容易相互交叠的问题,提出一种基于非线性编码的叠加概率整形(PS)20阶正交幅度调制(20QAM)星座方案。首先,基于提出的非线性编码方程,将等概率的4级电平信号编码为PS 5级电平信号。然后,将PS 5级电平信号映射为梯形形状的PS 5QAM信号以最大化叠加星座的欧氏距离。最后,将PS 5QAM信号与等概率的4QAM信号进行翻转叠加得到PS 20QAM信号。实验结果证明:所提出的叠加20QAM星座方案对系统的非线性失真有较强的鲁棒性,比叠加16QAM、叠加24QAM星座方案的误码率性能更优。Aiming at the problems of high computational complexity and easy overlap of adjacent constellation points in multi-in-put multi-output visible light communication systems,a superposed probabilistically shaped(PS)20-1evel quadrature amplitude modulation(20QAM)constellation scheme based on nonlinear coding is proposed.Firstly,based on the proposed nonlinear cod-ing equation,a 4-level signal with equal probability is encoded into a PS 5-level signal.Then,the PS 5-level signal is mapped into a trapezoid-shaped PS 5QAM signal to maximize the Euclidean distance of the superposed constellation.Finally,the PS 5QAM signal is superposed with an equal-probability 4QAM signal to obtain a PS 20QAM signal.The experimental results prove that the proposed superposed 20QAM constellation scheme has strong robustness to nonlinear distortion of the system and better bit error rate performance than superposed 16QAM and superposed 24QAM constellation schemes.

关 键 词：可见光通信 非线性编码 多输入多输出 概率整形 叠加星座 

分 类 号：TN929.12[电子电信—通信与信息系统]