This piece was originally published in the February 2017 issue of electroindustry.
Smart lighting can deliver traditional illumination and provide new functionality. The Internet of Things, connected lighting, and smart lighting are terms commonly used in the lighting industry today. In the initial period of solid state lighting advancement, light-emitting diode (LED) sources succeeded in saving energy in most lighting applications. Now, with better lighting controls and connectivity to a network, LED lighting is evolving to provide greater value to end users.
To address security concerns and bandwidth limitations of communications systems, communication using visible light is being considered and studied. This is called visual light communication (VLC) and has been given the name Li-Fi (Light Fidelity) by the IEEE standardization committee whose scope covers this technology.
Li-Fi systems are networked two-way data communication systems that use visible light by switching the current to the LEDs on and off at high temporal frequencies, beyond the flicker fusion frequency of the human visual system.
Li-Fi has the potential to be very high speed, perhaps as much as 100 times faster than Wi-Fi, with demonstrations claiming to have achieved data transmission rates from 500 mega-bits per second to nine gigabits per second (Gbps), and up to 200 Gbps.
Because communication uses visible light, it is limited to a line-of-sight, meaning that it cannot be used to communicate through walls or other such opaque obstacles. This limits the communication range compared to radio transmission, but has the benefit of not being detectable outside enclosed walls and is not easily subject to eavesdropping.
National Academies of Sciences, Engineering, and Medicine. 2016. Assessment of Advanced Solid-State Lighting, Phase 2. Washington, DC: The National Academies Press. doi: 10.17226/24619