Bai Ruowen, Hranilovic Steve
Opt Express. 2021 Mar 29;29(7):10613-10630. doi: 10.1364/OE.421108.
In this paper, antisymmetry-constructed clipped optical orthogonal frequency division multiplexing (AC-OFDM) is proposed for visible light communication (VLC) systems, in which an antisymmetry property is imposed directly in time domain. AC-OFDM has nearly the same spectral efficiency and peak-to-average power ratio (PAPR) as traditional asymmetrically clipped optical OFDM (ACO-OFDM) but is less complex to implement. Layered AC-OFDM (LAC-OFDM) is then proposed as an extension to further improve spectral efficiency, where different layers of AC-OFDM signals are added in the time domain and transmitted simultaneously. Computational complexity analysis and numerical results show that LAC-OFDM has nearly the same spectral efficiency as layered asymmetrically clipped optical OFDM (LACO-OFDM) and enhanced unipolar OFDM (eU-OFDM) but is less complex. Specifically, LAC-OFDM requires less than half the multiplication and addition operations compared to the comparable LACO-OFDM scheme. Additionally, a pairwise iterative receiver for LAC-OFDM is proposed and its computational complexity is analysed. Monte Carlo simulation results show that LAC-OFDM requires nearly the same optical signal-to-noise ratio (OSNR) to achieve the same BER performance as LACO- and eU-OFDM.
本文针对可见光通信（VLC）系统提出了基于反对称构造的削波光正交频分复用（AC-OFDM），其反对称特性直接在时域中施加。AC-OFDM具有与传统非对称削波光正交频分复用（ACO-OFDM）几乎相同的频谱效率和峰均功率比（PAPR），但实现复杂度更低。随后提出了分层AC-OFDM（LAC-OFDM）作为扩展，以进一步提高频谱效率，即不同层的AC-OFDM信号在时域中相加并同时传输。计算复杂度分析和数值结果表明，LAC-OFDM具有与分层非对称削波光正交频分复用（LACO-OFDM）和增强单极性OFDM（eU-OFDM）几乎相同的频谱效率，但复杂度更低。具体而言，与可比的LACO-OFDM方案相比，LAC-OFDM所需的乘法和加法运算少于其一半。此外，还提出了一种用于LAC-OFDM的逐对迭代接收机，并分析了其计算复杂度。蒙特卡罗仿真结果表明，LAC-OFDM需要与LACO-OFDM和eU-OFDM几乎相同的光信噪比（OSNR）才能实现相同的误码率性能。
