Light fidelity, or Li-Fi, is a visible light communication (VLC) system first introduced in 2011 by Harald Haas, a researcher from the University of Edinburgh. The system utilizes LEDs, which emit visible spectrum light with brightness that can be precisely controlled and modulated at very high speeds — so quickly that the light pulses go undetected by the human eye. Thus, users benefit from the seemingly unflickering illumination of Li-Fi-enabled LED light bulbs, while data is simultaneously transmitted at speeds potentially faster than Wi-Fi. A basic VLC system consists of an intensity-controlled light source and at least one receiver device with a light detector (photodiode) input into a chip that communicates with a PC or a mobile device
Li-Fi will not replace Wi-Fi. But because it promises high data-transfer rates, it will extend the high penetration rates of existing Wi-Fi technology, offering connectivity to the end user where Wi-Fi does not function well enough, is not possible, or is overloaded. How do Li-Fi and Wi-Fi work together? One example is video streaming versus downloading. Wi-Fi typically works well for streaming but not so well for downloading. Li-Fi can take up this slack because it has the potential to transmit at speeds an order of magnitude higher than Wi-Fi. A question that often arises is whether Li-Fi can or will use the same networking protocols as Wi-Fi. Will the standard Wi-Fi layer 2 MAC Ethernet or data link connection be sufficient? In fact, it is expected that protocol convergence will increase as Li-Fi standards progress. Specifically for 5G implementations, services that are switchable between Li-Fi and Wi-Fi will require the same protocols based on the MAC layer. The fifth generation of cellular mobile communications, 5G, is fast becoming a reality. It promises to move more data, be more responsive (with less latency), and connect more devices than today’s 4G networks. Utilizing its benefits will require greater speed and bandwidth than Wi-Fi can currently provide. This is where Li-Fi can step in, because the visible light spectrum is several orders of magnitude greater than the entire radio frequency spectrum. What’s more, the visible light region is unregulated, and so technology doesn’t need to be licensed in this frequency band. Both of these features make Li-Fi an excellent candidate to complement Wi-Fi systems in future 5G networks.
