A Channel Modeling Procedure for Visible Light Sensing

In this paper, we discuss a system-level tool based on Simulink/Matlab, Simscape, and Stateflow that allows us to simulate the received power of light reflected from surfaces in visible light sensing environments. Simulink and Stateflow are used in parallel to consider both continuous and instantaneous changes, while block parameters of physical modeling components are designed in Simscape, which consider data from manufacturer datasheets and/or measurements. With the help of this tool, one can evaluate the power of light, which is emitted from a light-emitting diode (LED), reflected at a surface and finally impinges on a photodiode, which acts as a receiver. This power depends on a variety of parameters, such as the spectral power distribution of the light source, the illuminance level at the reflective surface, the reflectivity properties of the reflective surface and the distances between LED, reflective surface and photodiode. Furthermore, we use differently colored surfaces, such as golden, reddish, and silvery surfaces and study their impact on the output voltage of the photodiode in different distances between the LED and the photodiode. In the end, we analyze and compare the results of the simulation with experimentally determined ones to demonstrate the applicability of the approach.