Optimum LED semiangle and the receiver FOV selection for Indoor VLC System with Human Blockages

In this paper, we have determined the optimum pair of light-emitting diode (LED) semiangle and the receiver field-of-view (FOV) in the presence of human blockages for indoor visible light communication (VLC) system. Firstly, we have calculated the optimum value of LED semiangle and the receiver FOV independently, keeping others constant. Secondly, we have jointly optimized both the LED semiangle and the receiver FOV. In the analysis, both LoS and NLoS up to the second-order have been considered. We have also incorporated the reflections from the human body, essentially the skin and the clothes, in the analysis as it impacts the received power. In order to obtain the optimum value of the LED semiangle and the receiver FOV, we have used the quality factor (Q) as a performance metric. In addition, the analytical expression for the achieved quality factor is derived for both single variable and joint optimization formulation. Results shows that with 2 and 5 blockages, the optimum pair using single and joint optimization is (63°, 65°) and (63°, 70°) for a separation distance of $D_{1}=40~{\mathrm cm}$ and (65°, 70°) and (65°, 75°) for $D_{2}=20~{\mathrm cm}$ respectively which provide the highest quality factor with minimum delay spread shown. Furthermore, the optimization analysis can also be mapped to different room sizes and LED placement, with static and dynamic blockages inside the room.