A novel PAPR reduction scheme for image transmission with ACO-OFDM VLC systems using chaotic scrambling and µ-modified logarithmic companding

Abstract

Visible-light communication (VLC) systems adopt orthogonal frequency-division-multiplexing (OFDM) modulation for high-data-rate transmission, as it offers better resistance to multipath fading and inter-symbol interference (ISI). However, a major challenge in ACO-OFDM-based VLC systems is high peak-to-average-power-ratios (PAPRs), which can degrade system performance. This paper proposes a combined chaotic scrambling and µ-nonlinear logarithmic companding transform scheme to solve the high PAPR problem and enhance image transmission quality in ACO-OFDM based-VLC systems. The proposed scheme utilizes the chaotic Arnold’s cat map-based scrambling (ACMS) for shuffling image pixels before modulation to improve image transmission quality and reduce PAPR. Moreover, a µ-modified logarithmic companding transform (µ-MLCT) is investigated to enhance the peak signal-to-noise ratio (PSNR), bit-error-ratio (BER), and reduce PAPR. ACMS can provide both data encryption and PAPR reduction. Simulation results confirm the effectiveness of the proposed scheme, which gives PSNR and BER improvements of about 52 dB and 3.5 dB in SNR, respectively, and achieves a PAPR reduction of about 12 dB. Moreover, it can not only achieve high image transmission security but also improve image quality and reduce PAPR in the ACO-OFDM-based VLC system without affecting PSNR and BER performance.