Capable of supporting the dual functionalities of dimming control and high-speed data transmission, dimmable optical orthogonal frequency division multiplexing (O-OFDM) has attracted increasing attentions in visible light communication (VLC). A major design challenge in the dimmable O-OFDM is to realize spectrally efficient VLC link compatible with dimming control while conforming to the low-complexity philosophy of the intensity modulation/direct detection (IM/DD) system. To cope with this challenge, a novel scheme is conceived, named as adaptively biased layered O-OFDM (ABLO-OFDM), which can be well integrated with the industry-preferred pulse width modulation (PWM) dimming technique. Similar to the conventional layered asymmetrically clipped O-OFDM (LACO-OFDM), multiple layers of subcarriers are utilized to transmit information data in ABLO-OFDM, resulting in high spectral efficiency. Only one inverse fast Fourier transform (IFFT) block is required in ABLO-OFDM to generate the layered O-OFDM signal compared to multiple IFFT blocks in LACO-OFDM. Moreover, the demodulation of the dimmable ABLO-OFDM (DABLO-OFDM) signal can straightforwardly rely on standard OFDM receiver, which is immune to the dimming process. Therefore, the proposed scheme achieves high spectral efficiency whilst possessing low-complexity transceiver compared to conventional O-OFDM. It is shown that DABLO-OFDM is superior to its counterparts in terms of the achievable spectral efficiency for intermediate dimming levels.

中文翻译：

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具有自适应偏置的分层光学 OFDM，用于调光兼容可见光通信


可调光正交频分复用（O-OFDM）能够支持调光控制和高速数据传输的双重功能，在可见光通信（VLC）领域引起了越来越多的关注。可调光 O-OFDM 的主要设计挑战是实现与调光控制兼容的频谱高效 VLC 链路，同时符合强度调制/直接检测 (IM/DD) 系统的低复杂性理念。为了应对这一挑战，人们构思了一种新颖的方案，称为自适应偏置分层 O-OFDM (ABLO-OFDM)，它可以与业界首选的脉宽调制 (PWM) 调光技术很好地集成。与传统的分层非对称限幅O-OFDM（LACO-OFDM）类似，ABLO-OFDM利用多层子载波来传输信息数据，从而具有高频谱效率。与 LACO-OFDM 中的多个 IFFT 块相比，ABLO-OFDM 中仅需要一个快速傅立叶逆变换 (IFFT) 块即可生成分层 O-OFDM 信号。此外，可调光 ABLO-OFDM (DABLO-OFDM) 信号的解调可以直接依赖标准 OFDM 接收器，不受调光过程的影响。因此，与传统的 O-OFDM 相比，所提出的方案实现了高频谱效率，同时具有低复杂度的收发器。结果表明，DABLO-OFDM 在中间调光级别可实现的频谱效率方面优于同类技术。