ABSTRACT
The globalization of electric lighting enabled the 24/7 economy during the second half of the 20th century—24 hours a day, 7 days a week. It is possible to divide lighting systems into three global classes: indoor lighting, outdoor lighting, and signaling. The four main components of the lighting system are the power source (PS), the lighting device (D), a reflector (R), and a shaping lens (L). The most common lighting devices available on the market are fluorescent lamps, compact fluorescent lamps (CFL), high-intensity discharge lamps (HIDs), light-emitting diode (LED), and more recently, laser-based visible lights. The impact of the lighting system on communications is limited to noise contribution of channel. Radiometry can be described as the detector-independent measurement of electromagnetic radiation, while photometry takes into account the detector, more specifically; detector reflects the response of the human visual system. Photometric measures are analogous to the above-mentioned radiometric quantities.
