Visible light communication (VLC) operates on optical intensity channels that are inherently limited in bandwidth. Though Kramers-Kronig (KK) receivers have been considered as a lower complexity alternative for coherent fiber optic communication (FOC) systems, in this paper we extend this concept to bandlimited IM/DD VLC channels and propose KK optical OFDM (KKO-OFDM). In KKO-OFDM the optical power of a low-cost LED is directly modulated by the double-sideband (DSB) squared modulus of a minimum phase single-sideband (SSB) signal. This results in a real-valued, non-negative and strictly bandlimited transmit signal which is suitable for VLC channels. At the receiver, the phase of the transmitted SSB signal is reconstructed via the KK relations. The required DC bias, average electrical signal-to-noise ratio (SNR), bit error rate (BER), and capacity are analyzed with approximate closed-forms and through simulation. Numerical results show that KKO-OFDM achieves the same spectral efficiency as the existing DC biased optical OFDM (DCO-OFDM), however, realizes approximately 1 dB optical SNR gain at a BER $=10^{-4}$ while simultaneously having a small peak-to-average power ratio.

中文翻译：

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用于带限强度调制可见光通信的 Kramers-Kronig 光 OFDM

可见光通信 (VLC) 在带宽固有受限的光强度通道上运行。尽管 Kramers-Kronig (KK) 接收器已被认为是相干光纤通信 (FOC) 系统的复杂度较低的替代方案，但在本文中，我们将这一概念扩展到了带限 IM/DD VLC 信道，并提出了 KK 光 OFDM (KKO-OFDM) . 在 KKO-OFDM 中，低成本 LED 的光功率由最小相位单边带 (SSB) 信号的双边带 (DSB) 平方模直接调制。这导致适用于 VLC 信道的实值、非负和严格带宽限制的传输信号。在接收端，通过 KK 关系重建传输的 SSB 信号的相位。所需的直流偏置、平均电信噪比 (SNR)、误码率 (BER)、和容量通过近似封闭形式和通过模拟进行分析。数值结果表明，KKO-OFDM 实现了与现有直流偏置光 OFDM (DCO-OFDM) 相同的频谱效率，但在 BER 下实现了大约 1 dB 的光 SNR 增益 $=10^{-4}$ 同时具有较小的峰均功率比。