PAPR Reduction Using Walsh-Hadamard Precoding in DHT-ACO-OFDM Based VLC Systems

  • Mohammed K. Mohaisen, Mounir T. Hamood, Mohammed Sh. Ahmed


Intensity modulation with direct detection (IM/DD) based on AC-biased optical orthogonal frequency division multiplexing (ACO-OFDM) is used in visible light communication (VLC) to send data at a fast rate. The peak of the transmitted signals is scaled up because OFDM signals are modulated using IM/DD, leading to a high peak-to-average power ratio (PAPR). The complexity of recovering the original signal at the receiver rises due to high PAPR's non-linear effects on the transmitted signal. In order to reduce the PAPR and obtain good bit error rate (BER) performance in such a system, the Walsh-Hadamard transform (WHT) is employed in this article as a precoding technique. The WHT decreases the input sequence's and the PAPR's autocorrelation. To ensure the new system's advantages and efficacy, comparisons between the suggested scheme and a conventional ACO-OFDM indoor VLC system based on discrete Hartley transform (DHT) are made.