Leible Benedikt, Plabst Daniel, Hanik Norbert
Institute for Communications Engineering, Technical University of Munich, Theresienstr. 90, 80333 Munich, Germany.
Entropy (Basel). 2020 Oct 6;22(10):1131. doi: 10.3390/e22101131.
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.
本文研究了利用非线性傅里叶变换进行联合调制离散谱和连续谱的数据传输。一种最近在探测器处用于纯离散特征值去除的方法被扩展到具有额外连续谱支持的信号。首先，依次检测特征值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范围可以缩小，直到所有特征值都被去除。然后，通过标准的非线性傅里叶变换（NFT）算法恢复理想情况下仅包含连续谱分量的所得截断信号。无光纤信道的数值模拟表明，对于联合调制的离散谱和连续谱，与现有检测方法相比，使用特征值去除方法可以降低发射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，每次去除步骤后的时间支持范围可以缩小时，两种谱分量检测的计算复杂度都可以降低。还对拉曼放大的有损单模光纤（SSMF）信道上的传输进行了数值模拟。近似了互信息，并表明特征值去除方法可实现速率提升。
