Enhancement of channel capacity of IRS-aided OWC system for 6G wireless communication

To meet the stringent ultra-reliable connectivity demands of 6G applications such as enhanced broadband and autonomous driving, optical wireless communication (OWC) is considered a key candidate technology. In this work, we investigate the performance of an intelligent reflecting surface (IRS)-aided OWC system by analyzing the signal-to-interference-plus-noise ratio (SINR), data rate, and sum rate through comprehensive MATLAB simulations. The impact of key system parameters on these performance metrics is systematically studied. Furthermore, an analytical expression for the optimal line-of-sight (LoS) channel gain is derived to maximize SINR, data rate, and sum rate. This optimization enables the selection of higher-order M-pulse amplitude modulation (M-PAM) schemes, thereby enhancing channel capacity (CC), spectral efficiency (SE), and energy efficiency (EE) of the IRS-aided OWC system. Simulation results demonstrate that for an SINR of 14.52 dB, 4-PAM is identified as the most suitable advanced digital modulation scheme for reliable data transmission. Additionally, the proposed system achieves a maximum sum rate of 32 Mbps for two mirror arrays and two blockages, which is approximately three times higher than the corresponding results reported in the existing literature. These findings highlight the substantial potential of IRS-assisted OWC systems as an enabling technology for future 6G networks.