In visible light communication (VLC) systems, optical orthogonal frequency division multiplexing (OOFDM) is used to reduce the effects of inter-symbol interference while simultaneously achieving fast data transmission speeds and large bandwidths. Asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) is one of the most OOFDM used. ACO-OFDM with low peak-to-average power ratio performance becomes essential for practical visible light communication broadcasting systems due to non-linearity elimination. The techniques for reducing the peak-to-average power ratio for visible light communication broadcasting systems are designed, simulated, and evaluated in this work. This work provides novel mixed Non-Liner Companding Techniques that target remarkable peak-toaverage power ratio performance with acceptable bit error rate performance for ACO-OFDMbased VLC systems. This work compares the designed techniques then nominates an optimum one that provides the optimum peak-to-average power ratio and bit error rate performance. Finally, the nominated technique will be compared to all related literatuers of ACO-OFDM-based VLC systems to ensure its novelty, validity, and effectiveness.

In this paper, a combination process for sub-carrier pulse modulation (SC-LPPM) technique with Mary Quadrature Amplitude Modulation OFDM (M-QAM OFDM) under distinctive and uniform lighting topologies assumption in a typical room is introduced. It was indicated from previous literatures that SC-LPPM fails to achieve the minimum performance required to achieve and sustain a reliable communication link; hence, it can be predicted that utilizing optical OFDM techniques can enhance the scheme performance allowing it to sustain a reliable communication link performance while achieving a higher operating data rate with an acceptable BER performance. However, the presented study can be more informative if the investigation is carried for different room and lighting topologies which will indicate the capabilities and the limitations of the proposed combination scheme. It can be shown in the manuscript that under distinctive lighting topology assumption, utilizing M-QAM OFDM with a single carrier modulation technique (SCM) like SC-LPPM can enhance the operating bit rate performance up to 50 Mbps with a remarkable BER performance of 8.610 -5 at modulation level (L=8), which can maintain a reliable communication link for Visible Light Communication (VLC) systems. Meanwhile, further improvement to the BER performance up to 9.5610 -6 can be achieved for the same modulation level at a 5 Mbps rate. Moreover, an investigation for the power performance of the proposed technique, the minimum required power, and the power distribution across the presented rooms topologies is presented in the manuscript under two scenarios (i.e., with and without utilizing SC-LPPM with M-QAM OFDM), which will help identifying the most suitable room and lighting layout to utilize the proposed scheme and give an insight into the performance enhancement that occurred due to the utilization of optical OFDM.