Gebeyehu Zelalem Hailu
Addis Ababa Science and Technology University, College of Electrical and Mechanical Engineering, Addis Ababa, Ethiopia.
Heliyon. 2020 Feb 6;6(2):e03363. doi: 10.1016/j.heliyon.2020.e03363. eCollection 2020 Feb.
sIn visible light communication (VLC) systems, a non-orthogonal multiple access (NOMA) scheme is deemed promising technology to offer better spectral efficiency than the Orthogonal multiple access (OMA) scheme. The feasibility of power domain NOMA for VLC system has been studied with different variants of unipolar OFDM schemes. However, few research works have been presented on the impact of clipping noise on the achievable sum rate of NOMA with DC-biased optical OFDM (DCO-OFDM) and polarity divided DCO-OFDM (PD-DCO-OFDM). This paper presents the impact of clipping noise on the achievable sum rate of NOMA-DCO-OFDM and NOMA-PD-DCO-OFDM VLC systems. Moreover, NOMA-DCO-OFDM and NOMA-PD-DCO-OFDM systems are compared based on achievable sum rates for different total power constraints and signal clipping levels. For the two-user scenario, Simulation results have confirmed that NOMA-PD-DCO-OFDM can offer a better sum rate compared to NOMA-DCO-OFDM system.
在可见光通信（VLC）系统中，非正交多址接入（NOMA）方案被认为是一种很有前景的技术，与正交多址接入（OMA）方案相比，它能提供更高的频谱效率。人们已经针对单极性正交频分复用（OFDM）方案的不同变体，研究了功率域NOMA在VLC系统中的可行性。然而，关于削波噪声对直流偏置光OFDM（DCO - OFDM）和极性分割DCO - OFDM（PD - DCO - OFDM）的NOMA可实现和速率的影响，目前的研究工作较少。本文阐述了削波噪声对NOMA - DCO - OFDM和NOMA - PD - DCO - OFDM VLC系统可实现和速率的影响。此外，基于不同的总功率约束和信号削波水平下的可实现和速率，对NOMA - DCO - OFDM和NOMA - PD - DCO - OFDM系统进行了比较。对于两用户场景，仿真结果证实，与NOMA - DCO - OFDM系统相比，NOMA - PD - DCO - OFDM能提供更好的和速率。
