基于星座成型技术的非线性噪声抗性星座图设计

Nonlinear Noise Resistance Constellation Design Based on Constellation Forming Technology

通过对星座成型技术中的几何成型和概率成型的研究,建立合理的数学模型设计最优化的星座图,来适应提升星座图的噪声容忍度,减小非线性干扰噪声.首先,在星座图满足Maxwell-Boltzman(MB)分布的条件下,建立PS-64QAM模型,通过运用二分法求解得到满足信息熵为5.0的星座图;其次,为解决光纤非线性问题,建立超高斯分布下的PS-64QAM优化模型,通过对超高斯分布的参数的探究,分别求得引入频带利用率的制约条件前后解调信号信噪比最大化的星座图;最后,在不改变信息熵的条件下,为达到更高的解调后信号的信噪比,同时引入PS技术和GS技术,建立几何概率混合成型64QAM模型(G/PS-64QAM),即在MB分布下PS-64QAM概率成型星座图的基础上,应用成对优化算法优化位置坐标,得到G/PS-64QAM模型下星座点的最佳分布位置.

In this paper,geometric shaping(GS)and probalisitic shaping(PS)in constellation shaping technology are studied,and a reasonable mathematical model is established to design the optimal constellation map,so as to adapt to and improve the noise tolerance of constellation map.To reduce the nonlinear interference noise,firstly,PS-64QAM model is established under the condition that the constellation diagram satisfied the Maxwell-Boltzman(MB)distribution,and the constellation diagram with the information entropy of 5.0 is obtained by using dichotomy method.Secondly,in order to solve the nonlinear problem of optical fiber,the optimization model of PS-64QAM under the super Gaussian distribution is established.By exploring the parameters of the super Gaussian distribution,the constellation of the maximum SNR of demodulation signal before and after the introduction of information entropy is obtained.Finally,in order to achieve a higher signal-to-noise ratio of the demodulated signal without changing the information entropy,PS technology and GS technology are introduced simultaneously to establish the geometric probability hybrid 64QAM model(G/PS-64QAM),that is,on the basis of the probability forming constellation of PS-64QAM under MB distribution,pairwise optimization(PO)algorithm is applied to optimize the location coordinates,and the optimal distribution position of constellation points in G/PS-64QAM model was obtained.