# Three-Dimensional Division of Visible Light Communication Irradiation Area
## 5 Summary  
In this paper, we discuss the effect of communication distance, transmitter half angle, irradiance half angle at the detector, irradiance half angle at the source, and detection surface area on the communication system. To study the effect of the change in the lampshade height on the VLC system, a 10 m LOS channel indoors was built using the IM/DD technique and a single white LED. In the experiment we creatively divided the entire communication range into three different optical signal receiving areas, and analyzed each area. The experimental results showed that area I was mainly affected by the reflected light at a short distance. Area II was a stable communication area whose communication range was positively related to the lampshade height. Area III was mainly affected by the communication distance and external environmental interference. The volume of area II in the entire optical signal receivable area accounted for more than 50%.  
Our future work will focus on communication stability issues in areas I and III. We may consider adding signal amplifiers at the transmitter side for improving signal strength. It would also be interesting to add filters in front of the receiver to reduce the effect of background light on visible light communications, and to use more sensitive photoelectric sensors to enhance the detection of faint light at the receiver side.  
The above methods could improve the communication performance of the whole system. This study has certain guiding significance for studying the distribution of optical signals and the improvement of communication performance in VLC.  
**Author Contributions:** Y.Z.: Conceptualization; Formal analysis; Investigation; Methodology; Software; Writing--original draft; Discussed the results and revised the manuscript. Y.D.: Data curation; Investigation; Validation; Discussed the results and revised the manuscript. H.W.: Data curation; Investigation; Validation; Discussed the results and revised the manuscript. L.C.: Data curation; Investigation; Validation; Discussed the results and revised the manuscript. G.X.: Conceptualization; Funding acquisition; Project administration; Resources; Writing--review and editing; Discussed the results and revised the manuscript. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported in part by grants from the National Natural Science Foundation of China (NSFC, No. 52075345), the Science and Technology Planning Project of Shenzhen Municipality (Grant no. JCYJ20190813111203628), the Ordinary University Engineering Technology Development Center Project of Guangdong Province (Grant No. 2019 GCZX006), the Department of Education of Guangdong Province (Grant No. 2019 KQNCX181).  
**Institutional Review Board Statement:** Not applicable.  
**Infrared Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors gratefully acknowledge the support from the National Natural Science Foundation of China, the Science and Technology Planning Project of Shenzhen Municipality, the Ordinary University Engineering Technology Development Center Project of Guangdong Province and the Department of Education of Guangdong Province. [PERSON] would also like to thank [PERSON], [PERSON], and [PERSON], who conceived the idea of the study.  
**Conflicts of Interest:** The authors declare no conflict of interest.