# Three-Dimensional Division of Visible Light Communication Irradiation Area
###### Abstract  
In this article, we divide the irradiated area of visible light communication (VLC) into three parts, according to the influence of diffuse reflection, the irradiance half angle at the source and the communication distance on VLC. We present a volume ratio method to quantitatively analyze each divided part. In this work, based on the Lambertian reflection model of the VLC system in line-of-sight channels, five factors affecting the VLC performance are compared and discussed. A VLC system of a single white-light-emitting diode in a 10 m line-of-sight channel indoors is designed by using the intensity modulation and direct detection technique, and a three-dimensional model of the irradiated area is established.By comparing the distribution of the bit error rate (BER) of the optical signal at different lampshade heights, the volume ratio method is used to calculate the volume percentage of the three irradiated areas. The experimental results show that area II with a volume ratio greater than 50% is the best signal receiving area when compared with areas I and III, having a volume ratio in the range 20\(\sim\)30%. bit error rate; intensity modulation and direct detection technique; line-of-sight channels; visible light communication; volume ratio +
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influences the above indicators, which in turn affects the quality of the communication performance. Therefore, when the parameters of the transmitter remain unchanged, ensuring that there is a sufficiently large receivable area for optical signals in the communication channel has a great impact on improving the communication performance of VLC systems. The communication channel is an important part of the whole VLC system. Related studies have shown that the improvement of communication channels helps to enhance the communication performance of the system. Both LOS channels and non-LOS (NLOS) channels are analyzed in the literature [33; 34; 35]. [PERSON] et al. [33] analyzed the effect of reflected light from walls on the receiver side by simulating a LOS channel and an NLOS channel. By arranging multiple LEDs in both LOS and NLOS channels, [PERSON] et al. [34] improved the uniformity of light illumination within the communication channel and mitigated the effect of inter-symbol interference. [PERSON] [35] researched the performance evaluation of a VLC system with various FOVs, elevation and azimuth receivers by simulating LOS and NLOS models. A mixed-integer linear programming model was developed. At the same time, some researchers have turned their attention to VLC channels in different application scenarios. [PERSON] et al. [36] introduced a VLC channel for I2V communication. The corresponding propagation model was established by linear regression. The proposed model showed higher accuracy than the traditional Lambertian model. [PERSON] et al. [37] investigated the VLC channel's characteristic evolution from the conventional Lambertian beam to typical non-Lambertian beams. Studies have shown that side-emitter beams provide a more uniform capacity distribution in a distributed transmitter configuration. [PERSON] et al. [38] proposed a three-dimensional space-time-frequency non-stationary-geometry-based stochastic model for indoor VLC channels. The accuracy and practicality of the model were verified by simulation experiments. [PERSON] et al. [39] proposed a hemispherical three-dimensional dust particle distribution model based on an underground mining scenario. By comparing with other models, the proposed model was found to be more accurate and realistic in terms of metrics assessment. [PERSON] et al. [40] constructed a neural-network-based transceiver for compensating the effect of variable inter-symbol interference in a VLC system. The results showed that the neural-network-based transceiver performed well in terms of symbol error rate.