The present contribution proposes a general framework for the energy efficiency analysis of a hybrid visible light communication (VLC) and Radio Frequency (RF) wireless system, in which both VLC and RF subsystems utilize nonorthogonal multiple access (NOMA) technology. The proposed framework is based on realistic communication scenarios as it takes into account the mobility of users, and assumes imperfect channel-state information (CSI). In this context, tractable closed-form expressions are derived for the corresponding average sum rate of NOMA-VLC and its orthogonal frequency division multiple access (OFDMA)-VLC counterparts. It is shown extensively that incurred CSI errors have a considerable impact on the average energy efficiency of both NOMA-VLC and OFDMAVLC systems and hence, they should not be neglected in practical designs and deployments. Interestingly, we further demonstrate that the average energy efficiency of the hybrid NOMA-VLCRF system outperforms NOMA-VLC system under imperfect CSI. Respective computer simulations corroborate the derived analytic results and interesting theoretical and practical insights are provided, which will be useful in the effective design and deployment of conventional VLC and hybrid VLC-RF systems.

中文翻译：

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具有不完善信道状态信息的混合 VLC-RF 网络的非正交多址接入

目前的贡献为混合可见光通信 (VLC) 和射频 (RF) 无线系统的能效分析提出了一个通用框架，其中 VLC 和 RF 子系统都利用非正交多址 (NOMA) 技术。所提出的框架基于现实的通信场景，因为它考虑了用户的移动性，并假设了不完善的信道状态信息 (CSI)。在这种情况下，针对 NOMA-VLC 及其正交频分多址 (OFDMA)-VLC 对应物的相应平均总速率导出了易于处理的封闭形式表达式。广泛表明，发生的 CSI 错误对 NOMA-VLC 和 OFDMAVLC 系统的平均能效都有相当大的影响，因此，在实际设计和部署中不应忽视它们。有趣的是，我们进一步证明了混合 NOMA-VLCRF 系统的平均能量效率在不完美的 CSI 下优于 NOMA-VLC 系统。各自的计算机模拟证实了推导出的分析结果，并提供了有趣的理论和实践见解，这将有助于传统 VLC 和混合 VLC-RF 系统的有效设计和部署。