In this paper, data-transmission using the nonlinear Fourier transform for jointly modulated discrete and continuous spectra is investigated. A recent method for purely discrete eigenvalue removal at the detector is extended to signals with additional continuous spectral support. At first, the eigenvalues are sequentially detected and removed from the jointly modulated received signal. After each successful removal, the time-support of the resulting signal for the next iteration can be narrowed, until all eigenvalues are removed. The resulting truncated signal, ideally containing only continuous spectral components, is then recovered by a standard NFT algorithm. Numerical simulations without a fiber channel show that, for jointly modulated discrete and continuous spectra, the mean-squared error between transmitted and received eigenvalues can be reduced using the eigenvalue removal approach, when compared to state-of-the-art detection methods. Additionally, the computational complexity for detection of both spectral components can be decreased when, by the choice of the modulated eigenvalues, the time-support after each removal step can be reduced. Numerical simulations are also carried out for transmission over a Raman-amplified, lossy SSMF channel. The mutual information is approximated and the eigenvalue removal method is shown to result in achievable rate improvements.

中文翻译：

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全谱非线性傅立叶变换及其逆的背靠背性能

在本文中，研究了使用非线性傅立叶变换进行联合调制的离散和连续光谱的数据传输。最近在检测器上去除纯离散特征值的方法扩展到具有附加连续谱支持的信号。首先，特征值被依次检测并从联合调制的接收信号中去除。每次成功去除后，下一次迭代所得信号的时间支持可以变窄，直到所有特征值都被去除。得到的截断信号，理想情况下只包含连续的频谱分量，然后通过标准的 NFT 算法恢复。没有光纤通道的数值模拟表明，对于联合调制的离散和连续光谱，与最先进的检测方法相比，使用特征值去除方法可以减少发送和接收特征值之间的均方误差。此外，当通过选择调制特征值可以减少每个去除步骤之后的时间支持时，可以降低检测两个频谱分量的计算复杂度。还对通过拉曼放大、有损 SSMF 通道的传输进行了数值模拟。相互信息是近似的，特征值去除方法显示出可实现的速率改进。通过选择调制特征值，可以减少每个去除步骤后的时间支持。还对通过拉曼放大、有损 SSMF 通道的传输进行了数值模拟。相互信息是近似的，特征值去除方法显示出可实现的速率改进。通过选择调制特征值，可以减少每个去除步骤后的时间支持。还对通过拉曼放大、有损 SSMF 通道的传输进行了数值模拟。相互信息是近似的，特征值去除方法显示出可实现的速率改进。