Hermitian symmetry (HS) is essential for attaining a real-valued signal for intensity modulation and direct detection of visible light communication (VLC). However, HS results in an increase of the peak-to-average power ratio (PAPR). We propose an HS free direct current optical-universal filtered multicarrier (HSF DCO-UFMC) system for VLC. In this technique, the conventional complex UFMC signal is transformed by juxtaposing the real and imaginary components to attain a real valued signal. Therefore, HSF DCO-UFMC offers a great reduction of the PAPR. We also address the nonlinear companding transforms for further reduction of the PAPR of the HSF DCO-UFMC signal. A new companding transform called two μ-law that reduces the PAPR and provides more design flexibility by employing two optimum companding levels and a threshold value is proposed for the HSF DCO-UFMC system. However, this scheme raises the average power level of the signal. So, to maintain a constant average power level, an enhanced two μ-law is proposed to reduce the PAPR effectively. Simulation outcomes exemplify that the proposed HSF DCO-UFMC provides better PAPR reduction. In addition, the proposed two μ-law and enhanced two μ-law can provide an improved PAPR reduction, suppressed side-lobe levels, and better bit error rate performance than the original HSF DCO-UFMC signal.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.