The line-of-sight (LoS) channel is one of the requirements for efficient data transmission in visible-light communications (VLC), but this cannot always be guaranteed in indoor applications for a variety of reasons, such as moving objects and the layout of rooms. The relay-assisted VLC system is one of the techniques that can be used to address this issue and ensures seamless connectivity. This paper investigates the performance of half-duplex (HD) conventional DF relay system and cooperative systems (i.e., selective DF (SDF) and incremental DF (IDF)) over VLC channels in terms of outage probability and energy consumption. Analytical expressions for both outage probability and the minimum energy-per-bit performance of the aforementioned relaying systems are derived. Furthermore, Monte Carlo simulations are provided throughout the paper to validate the derived expressions. The results show that exploiting SDF and IDF relaying schemes can achieve approximately 25% and 15% outage probability enhancement compared to single-hop and DF protocols, respectively. The results also demonstrate that the performance of the single-hop VLC system deteriorates when the end-to-end distances become larger. For example, when the vertical distance is 3.5m, the single-hop approach consumes 20%, 40% and 45% more energy in comparison to the DF, SDF, and IDF approaches, respectively.

中文翻译：

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VLC通道上的合作和非合作中继的性能分析。

视距（LoS）通道是在可见光通信（VLC）中进行有效数据传输的要求之一，但是由于种种原因（例如移动物体和布局），在室内应用中并不能始终保证这一点房间。中继辅助VLC系统是可用于解决此问题并确保无缝连接的技术之一。本文从中断概率和能耗方面研究了VLC通道上半双工（HD）常规DF中继系统和协作系统（即，选择性DF（SDF）和增量DF（IDF））的性能。导出了上述中继系统的中断概率和最小每比特能量性能的解析表达式。此外，整篇文章都提供了蒙特卡洛模拟，以验证派生的表达式。结果表明，与单跳和DF协议相比，利用SDF和IDF中继方案分别可以实现大约25％和15％的断电概率提高。结果还表明，当端到端距离变大时，单跳VLC系统的性能会下降。例如，当垂直距离为3.5m时，与DF，SDF和IDF方法相比，单跳方法分别消耗20％，40％和45％的能量。结果还表明，当端到端距离变大时，单跳VLC系统的性能会下降。例如，当垂直距离为3.5m时，与DF，SDF和IDF方法相比，单跳方法分别消耗20％，40％和45％的能量。结果还表明，当端到端距离变大时，单跳VLC系统的性能会下降。例如，当垂直距离为3.5m时，与DF，SDF和IDF方法相比，单跳方法分别消耗20％，40％和45％的能量。