The evolution of data-intensive services and applications continues to drive the need for higher data rates in wireless communication systems, consequently depleting the radio frequency (RF) spectrum. Due to the unlicensed and enormous bandwidth available in the visible light (VL) spectrum, the emergence of visible light communication (VLC) has been considered a potential solution to alleviate the constraints associated with RF spectrum scarcity. However, the line-of-sight requirement and the inability of VL to penetrate opaque obstacles remain a daunting challenge in realizing a wider coverage area. The incorporation of cooperative communication in VLC systems serves as one of the primary solutions to address this challenge. Though various investigations are currently being conducted in this domain, a holistic report of various advances, solution approaches, and design challenges has not been captured in the open literature. Therefore, in this paper, our main goal is to present a review of the state-of-the-art research on cooperative VLC systems. Firstly, we provide a background discussion to establish the relationship between various components of cooperative VLC systems from a theoretical and analytical perspective. Secondly, we categorize various contributions in this direction under media access control (MAC), hybrid VLC-RF, power line communication-VLC (PLC-VLC), and VLC with energy harvesting. Based on the established categories, we identify various system design and evaluation methods, optimization problems, solution approaches adopted to tackle the problems, and their limitations. Thirdly, we identify various insights obtained from the presented papers that could serve as guidelines for practical system design. Finally, various design challenges and open areas for future research are identified.

中文翻译：

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合作可见光通信：概述与展望


数据密集型服务和应用的发展不断推动无线通信系统对更高数据速率的需求，从而耗尽射频 (RF) 频谱。由于可见光 (VL) 频谱中可用的无需许可且巨大的带宽，可见光通信 (VLC) 的出现被认为是缓解与射频频谱稀缺相关的限制的潜在解决方案。然而，视线要求和VL无法穿透不透明障碍物仍然是实现更广泛覆盖区域的艰巨挑战。将协作通信纳入 VLC 系统是应对这一挑战的主要解决方案之一。尽管目前正在该领域进行各种调查，但公开文献中尚未捕获各种进展、解决方案方法和设计挑战的整体报告。因此，在本文中，我们的主要目标是对协作 VLC 系统的最新研究进行回顾。首先，我们提供背景讨论，从理论和分析的角度建立协作 VLC 系统各个组件之间的关系。其次，我们将这个方向的各种贡献分为媒体访问控制（MAC）、混合VLC-RF、电力线通信-VLC（PLC-VLC）和具有能量收集的VLC。根据已建立的类别，我们确定了各种系统设计和评估方法、优化问题、解决问题所采用的解决方法及其局限性。第三，我们确定了从所提出的论文中获得的各种见解，这些见解可以作为实际系统设计的指南。 最后，确定了各种设计挑战和未来研究的开放领域。