In this paper, a hybrid technique using a precoder and a µ law compander is proposed to alleviate light emitting diode (LED) nonlinearity as well as peak-to-average power ratio (PAPR) reduction in a VLC system. A µ law compander is used to compress the peak valued signal and enhances small amplitudes to lower the PAPR. The work attains optimal PAPR and improves bit error rate (BER) of the system at low signal to noise ratio values. The nonlinear characteristic of a LED used as the transmitter in a VLC system leads to damaging effects while using OFDM in an optical system. The combination scheme improves LED nonlinearity for low input back off (IBO) power. In the work, nonlinearity is characterized using error vector magnitude (EVM) in percentage. The proposed method shows a 5% EVM improvement for 0 dB IBO. The paper provides a choice for a trade-off among PAPR reduction, BER and reduced nonlinearity.

中文翻译：

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在可见光通信 (VLC) 系统中使用预编码和压扩混合的 PAPR 降低和非线性缓解

在本文中，提出了一种使用预编码器和 µ 律压扩器的混合技术，以减轻 VLC 系统中的发光二极管 (LED) 非线性以及峰均功率比 (PAPR) 的降低。µ 律压扩器用于压缩峰值信号并增强小幅度以降低 PAPR。该工作在低信噪比值下获得了最佳 PAPR 并提高了系统的误码率 (BER)。在 VLC 系统中用作发射器的 LED 的非线性特性会导致在光学系统中使用 OFDM 时产生破坏效应。该组合方案改善了 LED 非线性，以实现低输入回退 (IBO) 功率。在这项工作中，非线性是使用百分比误差矢量幅度 (EVM) 来表征的。建议的方法显示了 0 dB IBO 的 5% EVM 改进。