## 4 Simulation Results and Discussion
### Channel Impulse Response of the VLC System  
We consider a number of coherent optical paths (rays) to obtain relevant results without consuming excessive computational resources. Furthermore, we calculate the received power and the Euclidean distance between the LED and the PD to obtain the length of each of the optical rays and assume the value of \(P\) based on the Gaussian Bimodal Distribution [29]. This methodology involves the variation of the position of the PD throughout the scenario and its effect on the system performance by changing the distance between the PD with the LED and the PD with the IRS. Finally, these variables are processed by theoretical calculations to obtain the BER considering the average of all PD positions and the total CIR in the scenario and for various values of \(P\). For simulation purposes, we assume that the transmitted power is 20 watts.  
Figure 4 shows the distribution of CIR throughout the simulated environment for some values of \(n_{m}\). We can see that, as with the BER, for a value of \(n_{m}=16\) (Figure 4a), the best CIR results are obtained in terms of their amplitude value. Indeed, we can see that the maximum and minimum CIR values obtained in the indoor scenario are \(2.2\times 10^{-6}\) and \(0.25\times 10^{-6}\), respectively. These values are the best obtained if we compare them with the values obtained for \(n_{m}=8\) (Figure 4b) and \(n_{m}=4\) (Figure 4c). Therefore, these findings reinforce our criteria to improve system performance by increasing the values of \(n_{m}\). We can also notice in all scenarios that the magnitudes of the CIR are not uniform; this is due to the different distances between the LED and the PD and their effect on reception, as well as the distances between the LED, the IRS, and the PD. Another important factor that produces the nonuniformity of the CIR in the scenario is the probability of blocking the LoS signal. At the signal blocking points, we can observe a lower CIR, in which the Non-LoS component produced by the reflections in the IRS prevails. This gives us a positive effect on the performance of the system, since there is never a total loss of optical signal around the indoor scenario.  
Finally, Figure 5 shows the CIR curves obtained by varying the P values for a PD located in the center of the scenario. As we can see, when the values of \(P\) decrease (i.e., the probability of nonblocking of the optical link decreases), the maximum magnitude obtained by the initial LoS component also decreases. This effect is coherent since the partial or total blocking of this component is a critical factor in the received power. However, we realize that, despite the fact that there is blocking of the optical signal, the reflection components produced by the IRS are maintained and differ very little in magnitude for the different values of \(P\). In fact, for a value of \(P=0\) (full blocking), the components produced by the IRS remain at a good level. This allows us to analyze and identify the constructive effect of these elements in keeping a VLC system stable in performance.  
Figure 4: CIR distribution on the VLC scenario for some values of \(n_{m}\). (**a**) \(n_{m}=16\). (**b**) \(n_{m}=8\). (**c**) \(n_{m}=4\).