Generalized parabolic function for reduced PAPR in optical OFDM systems

Abstract In visible light communication (VLC) systems, orthogonal frequency division multiplexing (OFDM) is often used, but its high peak-to-average power ratio (PAPR) reduces system efficiency. To address the significant PAPR challenge in direct current–biased optical OFDM (DCO-OFDM), asymmetrically clipped optical OFDM (ACO-OFDM), and FLIP-OFDM configurations, the generalized parabolic companding function is employed with a shaping parameter called p . Unlike typical μ-law and A-law companding systems, which use fixed nonlinear compression, the shaping parameter controls the compression effect on the signal and enables a more efficient trade-off between PAPR reduction and bit error rate (BER) degradation. The proposed method is simulated in MATLAB for 16-QAM modulation over an optical channel with different inverse fast Fourier transform (IFFT) sizes and companding parameter values. At a complementary cumulative distribution function (CCDF) of 10 −3 , the system achieves PAPR reductions of 1.7137 dB for DCO-OFDM, 3.0101 dB for ACO-OFDM, and 3.1032 dB for FLIP-OFDM. As a result, the signal peaks are reduced, decreasing PAPR. In contrast, signal distortion increases due to increased compression, which subsequently impacts BER. The most optimal PAPR reduction/BER performance compromise is achieved at p = 1.6, while p = 2.0 results in the greatest PAPR reduction and the most significant BER degradation.