This article reviews the recent investigations on improving modulation designs for visible light communication (VLC) systems subject to signal-dependent noise (SDN). The existence of signal-dependent noise degrades the system performance and leads to modulation deficiency issues due to the constellation distortion caused by the SDN. For single-carrier systems, a joint constellation and threshold design was recently proposed to compensate the SDN, and it is re-analyzed in this article together with an improved design criterion based on the rotated minimum Euclidean distance (MIN-ED) that was employed to enhance modulation efficiency in multi-carrier systems. These design criteria are further ameliorated by optimizing the distance-range. Performance comparisons between improved and MIN-ED-based designs for VLC-SDN systems under communications and lighting constraints are also presented to illustrate the major limitations of current modulations. This article concludes with critical implementation challenges and future research opportunities.

中文翻译：

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改进具有信号相关噪声的可见光通信的调制设计

本文回顾了最近关于改进受信号相关噪声 (SDN) 影响的可见光通信 (VLC) 系统调制设计的研究。由于SDN引起的星座失真，信号相关噪声的存在会降低系统性能并导致调制不足问题。对于单载波系统，最近提出了一种联合星座和阈值设计来补偿SDN，并在本文中重新分析了它以及基于旋转最小欧几里德距离（MIN-ED）的改进设计标准，该标准采用了以提高多载波系统中的调制效率。通过优化距离范围进一步改善了这些设计标准。还介绍了在通信和照明限制下的 VLC-SDN 系统改进设计和基于 MIN-ED 的设计之间的性能比较，以说明当前调制的主要限制。本文总结了关键的实施挑战和未来的研究机会。