German professor Harald Haas coined and introduced the term Li-Fi during his 2011 TEDGlobal Talk. He explained that wireless data transmission could be integrated with existing LED lighting fixtures and systems. His team at the University of Edinburgh demonstrated this process through a funded project that commenced in 2010 and ended in 2012. Haas now owns and operates the company PureLiFi as part of his attempt to commercialize LED-based Li-Fi products.
Nonetheless, although the history of optical wireless communication and visible light communication technologies dates back to 1880s, the presentation of Haas marked a renewed interest in exploring wireless communication technologies beyond radio waves and microwaves. Take note that several companies and industry groups launched the Li-Fi Consortium in 2011 to develop Li-Fi technologies further.
But how does Li-Fi work? This article provides a concise and simplified explanation of the operational and working principle behind Li-Fi technology.
How Does Li-Fi Work: A Quick Explainer
The working principle behind Li-Fi is simple. This technology is fundamentally similar to Wi-Fi and other wireless communication technologies because it also uses electromagnetic radiation to transmit data over free space. Note that it also has its fair share of advantages and disadvantages.
However, it is important to note that Wi-Fi and most wireless communication technologies such as Bluetooth and long-distance 3G, 4G and 4G LTE, and 5G technologies use radio waves and microwaves. Li-Fi uses higher-frequency electromagnetic radiation within the infrared light, the visible light, and ultraviolet radiation region of the electromagnetic spectrum.
Existing Li-Fi operational concepts and experimental applications currently involve the use of visible light. To be specific, the team of Haas and other groups and companies have promoted the use of light-emitting diode or LED lamps to transmit data wirelessly. These lamps are essentially the router used for processing data from an external source and forwarding the corresponding data packets between computers or devices.
LED lamps are ideal for Li-Fi implementation because they can be dimmed up and down at extremely high speeds without being visible to the human eyes. The intended flickering or the tiny changes in the rapid dimming LED lamp correspond to a signal.
Of course, when used as a Li-Fi product, a LED lamp is equipped with a signal processing technology to process data from an external source such as an optic fiber cable line and to convert such data further into “light signals” for forwarding to receivers called photo-detectors or photodiodes. It is important to reiterate the fact that these light signals correspond to the flickering or dimming of the LED lamp.
The receiver processes the signals or the rapid dimming of the LED lamp to convert them into electrical signals and process or convert such further back into a binary data stream that would be displayed as a graphic content such as an audio or video file, applications, and websites, among others running on a computing device such as computers or smartphones.
A Summary of How Li-Fi Works
The following is a quick rundown of the working principle behind Li-Fi technology based on the discussion above:
• Data from an external source such as the fiber optic or copper cable of an Internet Service provider is fed into a Li-Fi LED lamp which acts as a router.
• The LED lamp processes these data from the external source and convert them to light signals using a signal processing technology.
• Light signals are characterized by the flickering or very rapid dimming of a LED bulb at different rates and intensities.
• The light signals are forwarded to a receiver attached to a computing device, which then processes such signals into electric signals and converts them back further into a binary data stream.
• Note that a computing device processes the binary data stream to display such as a graphic content, program or application, and websites, among others.