PAPR reduction based on deep autoencoder for VLC DCOOFDM system DCbiased optical orthogonal frequency division multiplexing (DCOOFDM) is widely used in visible light communication (VLC) systems to reduce the effects of intersymbol interference (ISI) and to achieve high speed data transmission. However, DCOOFDM VLC systems suffer from high peaktoaverage power ratio (PAPR) issue which causes serious degradation of system performance. In this paper, a novel deep autoencoderbased PAPR reduction scheme for VLC DCOOFDM is proposed. The autoencoder could adaptively adjust the constellation symbols in order to minimize the PAPR while maintaining an acceptable bit error rate (BER) for VLC transmission. The simulation results show that PAPR is reduced to 6. 5dB by comparing with conventional methods.

Performance Analysis on Hybrid OOKandOFDM Modulation in VLC System Since visible light communication (VLC) could support highspeed broadband transmission and be combined with existing illumination system, it is an optional technology for multimedia broadcasting, especially for indoor scenario. Furthermore, hybrid modulation could be applied in VLC system to assist data transmission or expand new functions. Researches and experiments show that conventional onoff key (OOK) and orthogonal frequency division multiplexing (OFDM) could be implemented successfully in VLC system respectively, thus it seems that a direct adding of OOK and OFDM signal is a feasible method for hybrid modulation. However, nonlinearity of electrooptical converting in VLC transmitter makes the relationship between transmission performance and amplitude of OOK or OFDM signal different from that in radio frequency (RF) system. In this paper, a mathematical model is built to analyze its performance and predict the bit error rate (BER) using OOK and OFDM signal amplitude in a given VLC system in order to find proper parameters for higher transmission quality. Simulation is also implemented to prove the validity and accuracy of the model.