## 6 Discussion  
In this paper, we established a reference configuration using a single-LED transmitter and plotted its irradiance distribution at a short distance, specifically at \(y=1\) m. Subsequently, we proposed various LED array geometries with two design parameters: the half FOV \(\phi_{\frac{1}{2}}^{\prime}\) of each LED and \(d_{0}\). We examined the effect of each design parameter by plotting the SNR against distance for the square array transmitters with different values of \(\phi_{\frac{1}{2}}^{\prime}\), and then different values of \(d_{0}\). The results showed that the SNR increases as \(\phi_{\frac{1}{2}}^{\prime}\) decreases and \(d_{0}\) increases. By appropriately adjusting the design parameters, we achieved the reference irradiance distribution with all configurations while extending the communication range. This demonstrates that our method allows for obtaining the desired irradiance pattern by adjusting the orientation vectors of the LEDs, controlled by the value of \(d_{0}\), and the half FOV for each LED, thereby improving the SNR. In [37], the irradiance and SNR distributions of an indoor VLC system are compared for different configurations of an LED array consisting of 16 LEDs. The paper proposes three different arrangements. The first is a regular \(4\times 4\) square array with equal spacing between the LEDs. The second and third configurations include the same number of LEDs; however, the arrangement of the LEDs is different. The paper shows that their second and third models yield more uniform irradiance and SNR distributions throughout the room. On the other hand, in this study, we used LED arrays to alter the system performance as desired. Therefore, we aimed to increase the SNR rather than achieve uniformity. For a V2V VLC system, a uniform SNR across a plane at a certain distance is not required. Instead, a long communication range is preferred, which is not required for an indoor VLC system. By using different configurations of LED arrays, we achieved an increased communication distance while maintaining the desired irradiance pattern. The study in [31] aims to increase the communication distance of a V2V VLC system by overdriving the LED transmitter current and proportionally shortening the duration of the pulses. Although the study in [31] tried to reduce the duty cycles of the signals and keep the overall irradiance constant, the instantaneous irradiance of the LEDs in these short signals may pose a danger to human eye health. Unlike [31], in our study, the current and, naturally, the irradiance were kept constant, and the communication distance was increased by simply changing the geometric structures of the LED arrays. In [30], the irradiance distribution is shown from a top view, covering both lateral and longitudinal aspects. Our paper, however, offers a more comprehensive approach by plotting the irradiance distribution directly on the plane where the receiver is located, thus including both lateral and ground clearance. The study in [30] includes a comparison of day and night conditions, as well. We assumed clear weather conditions in our simulations; however, the exact compatibility of our chosen parameters with real conditions is not a concern, as our study serves as a proof of concept. On the contrary, this approach enhances the flexibility of our study and its applicability to various scenarios. The study in [35] presents SNR and distance graphs using square pixel photodiode arrays in the receiver to extend the communication range. In contrast, our paper improves the VLC performance by optimizing the transmitter side without enlarging the receiver. Additionally, in [35], simulations with different modulation schemes are conducted, with the transmitted power adjusted according to the needs of each scheme. In contrast, our study maintains a constant transmitted power of 10 W across all proposed transmitter configurations, achieving increased communication ranges without varying the power.