Understanding Light Fidelity (Li-Fi) Technology
LiFi or Light Fidelity is a technology that uses light emitting diodes (LEDs) to transmit data wirelessly. It was first demonstrated at a TED talk in 2011 by German physicist Harald Haas. However, its commercial utilization has started only in 2015.
How it works?
Li-Fi uses LEDs and ‘visible’ light to transmit data wirelessly as an alternative to short-range radio.
It does not require any special LED bulbs but only standard LED bulbs used in houses and offices can be used. The bulbs are attached with a chip; and the output intensity of light from the bulb is modulated at nanosecond intervals to generate stream of binary codes (bit 1, if light is on, or bit 0, if light is off). A light-sensitive receiver in the receiving device detects the signals and the signal is demodulated into electronic form.
Though Li-Fi is a bidirectional technology, presently LEDs are used only to transmit data due to feasibility and cost issues involved. Li-Fi uses visible light band, between 400 and 800 THz (780–375 nm) of the electromagnetic spectrum to transmit data. Basic hardware required for functioning of Li-Fi are an LED lighting system, a router, and a receiver equipped with decoder. Filament bulbs and fluorescent tubes cannot be used since the light source has to be switched on and off for several thousands of times in a second.
What are its advantages?
The technology promises to transmit data at terabits per second speeds that is more than 100 times the speed of Wi-Fi. Scientists have achieved speeds in the lab of up to 224 GB per second. The technology offer solutions to overcome the problems of capacity limit and inefficiency in using Wi-Fi. The growing requirement of more data at faster rates has pushed Wi-Fi’s capacity to its limits. By 2019, the world may exchange about 35 quintillion bytes of data each month. The radio frequencies are already fully used by Wi-Fi. However, the visible light used in Li-Fi has a spectrum 10,000 times larger than radio waves used in Wi-Fi. That means Li-Fi has enormous capacity to transmit data through thousands of data streams simultaneously.
In Wi-Fi, the base stations transmitting radio waves works at about 5% efficiency only and most of the energy is used to cool the stations whereas Li-Fi works by using energy-efficient LED bulbs. There is also an issue of security in sending sensitive data through Wi-Fi as radio waves can travel through solid objects such as walls and doors. Li-Fi is short range and it doesn’t work through walls. The devices should be brought much closer than Wi-Fi to use Li-Fi, thus Li-Fi is more secure. The Li-Fi technology would not be affected by the number of devices using the signal, which is a bonus when compared to traditional Wi-Fi technology.
What are its potential applications?
Li-Fi has practical application both indoor and outdoor. By using the technology, every LED bulb in a house or office can be converted as a hotspot to transmit data. The technology can also be usable with street and traffic lights. Traffic management can be made intelligent by converting traffic lights into Li-Fi based access points. Accidents can be prevented with communication between vehicles having LED-based headlights and tail lamps. Similarly, street lights can also be converted as wireless hotspots for data transmission.
Visible light being safer, it can be used in nuclear and chemical plants, and in hospitals. Li-Fi can also be used in aircrafts where Wi-Fi communication is prohibited as it uses radio waves. As Li-fi works underwater, it has potential applications for military and navigation operations. The technology also presents a unique possibility wherein mobile phones can receive not only data but also power wirelessly for charging.
What are the challenges?
The main challenge is in conversion of existing devices into Li-Fi enabled ones by the use of a converter. And also chips that have light to electrical signal conversion system and data processing capability needs to be developed and manufactured. Another issue with Li-Fi is requirement of line of sight for communication and it also faces interference form external light sources like sun. The technology faces high installation costs until it becomes more commercial.
Will Li-Fi replace Wi-Fi?
Li-Fi technology may not completely replace Wi-Fi but both technologies could be used complementarily to create more efficient, green and future-proof transmission networks.
