Bit Error Rate Analysis of Visible Light Communication System Based on HDMA

This paper presents a novel downlink visible light communication (VLC) system leveraging hybrid domain multiple access (HDMA) technology. The system integrates power domain multiple access (PD-NOMA) in the power domain, sparse code multiple access (SCMA) in the code domain, and asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) in the frequency domain, aiming to enhance VLC performance and efficiency. We thoroughly examine the implementation principles, establish a VLC channel model, and analyze channel gain and signal-to-noise ratio (SNR) characteristics. Users are divided into two groups with distinct power levels, and SCMA is used for mapping and encoding, improving spectrum resource utilization. ACO-OFDM is employed for modulation, and the message passing algorithm (MPA) and successive interference cancellation (SIC) are joint used for detection. Theoretical expressions for average bit error rate (BER) are derived, and minimum power allocation ratios are determined to prevent signal overlap. Simulation results validate the theoretical analysis.