Visible light communication (VLC) has emerged as a promising solution for indoor communication due to its high efficiency and low power consumption. However, in practical applications, the uneven distribution of received power in indoor three-dimensional space significantly affects both the system’s communication quality and the fairness of received signals across different heights of receiving planes. This power unevenness can degrade communication performance and negatively affect user experience. Consequently, optimizing the layout of indoor light sources to enhance the uniformity of received power has become a key research area in VLC. We introduce an optimization method for optical power uniformity based on an improved Harris hawk optimization (IHHO) algorithm. The proposed algorithm integrates strategies such as the best point set, adaptive t-distribution perturbation mutation, and dynamic selection probability, combined with a nonlinear escape energy factor to enhance the global search capability during the exploration phase and the local search capability during the exploitation phase. This improves the algorithm’s adaptability, convergence speed, and accuracy. Building upon this, an optimization method is proposed for the LED transmitter light source layout. By simultaneously considering critical variables such as LED light source placement and transmission power, an optimization model is established to maximize coverage and ensure optimal uniformity of received optical power. The proposed algorithm is applied to refine the model further, which improves the uniformity of received optical power and the communication system’s coverage efficiency. This addresses the issue of uneven received power distribution in three-dimensional communication spaces, thereby enhancing signal transmission performance and ensuring fairness for users.

We propose a method based on the IHHO to optimize the light source layout of the indoor VLC system and improve the uniformity of optical power distribution in the receiving plane. First, an indoor VLC channel model is developed, and the transmission characteristics between the LED light source and the receiver photodiode (PD) are analyzed using the Lambert radiation model. We adjust the light source layout optimization scheme by assessing the effect of different light source configurations on the distribution of received optical power. The IHHO algorithm combines multiple strategies for optimization, with key enhancements including the introduction of an optimized point set strategy to improve the initial population and prevent premature convergence to local optima during initialization; the use of an adaptive t-distribution mutation strategy along with a nonlinear escape energy factor to balance global exploration and local exploitation, thereby improving convergence speed; the incorporation of a dynamic selection probability strategy to mitigate the risk of early convergence to suboptimal solutions. With these improvements, the IHHO algorithm effectively optimizes the light source layout, selects a more suitable LED light source configuration and transmission power scheme, reduces optical power dead zones in the receiving plane of the three-dimensional communication space, ensures a more uniform power distribution, and extends the effective communication coverage range.

In this study, the IHHO algorithm is employed to optimize the light source layout of the indoor VLC system, which leads to a significant improvement in the light power distribution in the receiving plane. In the initial (non-optimized) light source layout (Fig. 6), the receiving plane exhibits noticeable uneven power distribution, with lower received power in the edge regions. This unevenness is primarily due to the distance of the light sources and the effects of light reflection after it passes through the walls [Fig. 6(a)]. Additionally, at a receiving plane height of h=1.5 m, the variation in received power between the center and edge regions is substantial, which results in a marked power difference [Fig. 6(b)]. These uneven distributions negatively affect communication quality and lead to a lack of fairness in user communication. In the optimized LED layout (Fig. 8), the light source placement is optimized across three height planes (upper, middle, and lower) to improve the light power distribution. This optimization significantly enhances the uniformity of received light power throughout the communication space (Fig. 7). At h=0 m, the optimized layout notably improves the power uniformity of the receiving plane, with the received power quality factor rising to 1.82 [Fig. 7(a)]. At h=1.5 m, although there is still a power gap of approximately 5 dBm between the maximum and minimum received power, the overall power distribution is much more uniform compared to the unoptimized layout, and the received power quality factor increases to 1.51 [Fig. 7(b)]. Furthermore, Table 4 compares the system performance indicators before and after optimization, showing that the optimized layout not only enhances the power uniformity of the receiving plane but also increases the LED coverage. The LED coverage before optimization is 55%, while after optimization, it increases to 82% (Table 4).

In this study, we investigate the issue of uneven distribution of received optical power in indoor VLC systems and propose an optimization method for the light source layout based on the IHHO algorithm. The indoor three-dimensional communication space is divided into three planes—upper, middle, and lower, and the overall performance of received optical power at various heights is used as the objective function. An optimization model is established to maximize coverage and achieve uniformity of received optical power. By considering key variables such as the LED light source layout and transmission power, the model is finely optimized using the IHHO algorithm to determine the optimal light source layout. Compared to other traditional intelligent algorithms, the IHHO algorithm demonstrates clear advantages in optimization accuracy, convergence speed, and the ability to avoid local optima. Simulation results demonstrate that optimizing the light source layout with the IHHO algorithm effectively reduces optical power dead zones in the receiving area, improves the uniformity of received optical power distribution within the VLC system, enhances the effective coverage of the communication signal range, and improves communication fairness for indoor users.