## 4 Simulation Results and Discussion
### Bit Error Rate of the System  
Based on the IEEE 802.15.7 standard and the type of optical signal to comply with the IM/DD paradigm [30], in our work, the ON-OFF keying modulation (OOK) was used as shown in Table 1. Furthermore, the receiver location is varied and goes through the entire scenario to obtain the results. Finally, the shot and thermal noises widely used in typical VLC environments are considered [25; 26]. The BER was estimated using Monte Carlo simulations with the direct error counting method, that is, 21 runs of \(10^{5}\) bits were performed to have a confidence interval of 95% [25]. In this context, we measure the BER of the VLC system using typical standard equations and parameters for OOK modulation [25]. The simulated BER curves are shown in Figure 3, which measure the performance of the system based on the channel model proposed in Equation (14), the proposed VLC scenario, and the variation of \(n_{m}\) for different Signal-to-Noise-Ratio (SNR) values. For validation purposes, we adjust the value of \(P\) based on a Gaussian Bimodal distribution [29] and explicitly compare the curves obtained through simulations with the analytical BER evaluation, showing excellent agreement. From Figure 3, we can see that the best performance in terms of BER is obtained for \(n_{m}=16\). This result shows that the greater the number of rectangular optical smart \begin{table}
\begin{tabular}{l l l} \hline \hline
**System Model Parameters** & **Values** & **References** \\ \hline Average output optical power & 20 W & [9; 24; 26] \\ Band-pass filter of transmission & 1 & [24; 26] \\ Dimensions (w \(\times\) 1 x h) & (3 x 6 x 3) m & \\ Gain of the optical filter & 1 & [24; 26] \\ LED position (x, y, z) & (0, 3, 2) m & \\ LED semi-angle at half power & 60\({}^{\circ}\) & [24; 26] \\ Modulation & OOK & [24; 26] \\ Modulation bandwidth & 50 MHz & [24; 26] \\ Modulation index & 0.3 & [24; 26] \\ Number of PDs & 1 & \\ Open-loop voltage gain & 10 & [24; 26] \\ Optical filter bandwidth & 340 nm to 694.3 nm & [30] \\ Optical filter center wavelength & 340 \(\pm\) 2 nm & [30] \\ Optical filter full width half max & 10 \(\pm\) 2 nm & [30] \\ Phase discontinuity (\(\phi_{m}\)) & [\(-180^{\circ}\), \(180^{\circ}\)] & \\ PD physical area & 1 cm\({}^{2}\) & [24; 26] \\ PD FoV & 60\({}^{\circ}\) & [24; 26] \\ Refractive index & 1.5 & [24; 26] \\ Reflection coefficient & 0.8 & [24; 26] \\ Responsivity & 0.53 A/W & [24; 26] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Default simulations parameters. Figure 3: BER vs. SNR for different values of \(n_{m}\). metasurface patches that make up the IRS matrix, the greater the probability that they reach the receiver properly. This is due to the angular variation capacity so that when there is blocking of the LoS component, the Non-LoS component is the one that predominates, thus maintaining the power quality of the received signal. Therefore, this effect would improve the performance of the implemented VLC system. For example, for a BER of \(9\times 10^{-4}\), the SNR obtained is approximately 20 dB. On the other hand, for the same SNR value, we obtain an approximate BER of \(9\times 10^{-3}\) for \(n_{m}=8\) and \(9\times 10^{-2}\) for \(n_{m}=4\). These results demonstrate the positive effect of having a greater number of rectangular optical smart metasurface patches in the IRS. In order to obtain a complete approach to the variability of system performance according to changes in the PD position, we consider providing information on the BER standard deviation in our results. For \(n_{m}=4\) a standard deviation of 0.00154 was obtained, while for values of \(n_{m}=8\) and \(n_{m}=16\) values of 0.00143 and 0.00123 were obtained, respectively. This statistic allows us to intuit that the fluctuation of the BER in terms of the positions is appropriate for this type of system. Finally, we have observed that the value of \(n_{m}\) has a significant impact on the IRS about its performance in the VLC system.