QCTP: A Novel Pre-Coding Approach for PAPR Reduction in IM/DD Systems

Orthogonal frequency division multiplexing (OFDM) is critical for high-speed visible light communication (VLC) transmission; however, it suffers from a high peak-to-average power ratio (PAPR) problem. Among PAPR reduction techniques, pre-coding methods have shown promising advantages such as signal independence and no requirement for signaling overhead. This paper introduces a novel pre-coding technique termed quartered composite transform pre-coding (QCTP), which employs four newly developed orthogonal pre-coding matrices applied to four equally divided segments of modulated data, thereby enhancing the PAPR performance of VLC systems utilizing OFDM. This methodology allows the utilization of a single-tap equalizer, achieving over a 6 dB reduction in PAPR compared to conventional DCT pre-coding and surpassing the PAPR performance of DCT-hybridized (DCT & $\mu $ -compounding and DCT & Gaussian matrix) pre-coding techniques. This enhancement is accomplished without compromising bit error rate (BER) performance, all while maintaining reduced complexity.