Performance Analysis of Precoding with Adaptive Modulation Based OFDM Schemes in Visible Light Communication

In order to enhance Visible Light Communication (VLC), this study suggests a hybrid precoding and adaptive modulation-based Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) system. The primary goal is to improve power efficiency, lower the bit error rate (BER), and decrease distortion caused by the high Peak-to-Average Power Ratio (PAPR). Three precoding methods were examined and contrasted the hybrid DCT and DST, the discrete cosine transform (DCT), and the discrete sine transform (DST). By reducing PAPR from 8.7 dB to 4.7 dB for 4-QAM and from 10.4 dB to 6 dB for 256-QAM, an improvement of roughly 40-45%, the hybrid precoding scheme achieves the most effective performance, according to the simulation findings. Furthermore, the adaptive modulation method effortlessly modifies the modulation sequence (4-QAM, 16-QAM, 64-QAM, and 256-QAM) in response to the current signal-to-noise ratio (SNR), hence enhancing spectral efficiency and achieving a goal bit error rate (BER) below 10⁻³. The findings demonstrate that 16-QAM provides the optimal balance between dependability and throughput. Hybrid precoding and adaptive modulation offer a potential strategy for high-speed indoor VLC systems because they improve system performance, reduce nonlinearity effects, and increase spectral efficiency.