Abstract. The article provides mathematical modeling for indoor VLS based on MATLAB and Simulink. The program considers the positions of the transmitters and reflections on each wall. For the visible light environment, the LED lighting diode is used not only as a lighting device but also as a communication device. Using a simulation program, the distributions of illumination and RMS delay spread at the bottom surface are analyzed.

Keywords: networks, data transmission, data reception, LEDs, Li-Fi, VLC, lighting device, software, signal delay.