Is Li-Fi Better than Wi-Fi?

Li-Fi (light fidelity) is a bidirectional wireless system that transmit data to the devices like mobiles, laptop, etc., via infrared light or LED. The device has a receiver to pick up light signals and a transmitter to send light signal back to the lamp using infrared light or LED.

It was first unveiled in 2011 and, unlike Wi-Fi, which uses radio frequency, Li-Fi technology only needs a light source with a chip to transmit an internet signal through light waves.

Light fidelity (LiFi) is a faster, more secure and efficient wireless connection that uses light waves to transmit data

Li-Fi technology still has a long way to go before worldwide adoption but every year, we are getting nearer to enjoying it for ourselves. The future surely looks bright with LiFi.

How LiFi Works?

LiFi makes use of visible light through overhead lighting for the transmission of data. This is possible through the use of a Visible Light Communications (VLC) system for data transmission. A VLC system has two qualifying components:

1. At least one device containing a photodiode in order to receive light signals; and

2. A light source equipped with a signal processing unit for the transmission of signals.

The VLC light source can be in the form of a fluorescent bulb or a light emitting diode (LED). LED light bulbs are the most optimum VLC light source, however, since a robust LiFi system requires extremely high rates of light output. Fluorescent bulbs emit light in a much wider band of wavelengths, which makes it a relatively less efficient light source than LED. LED, on the other hand, is a light source that emits light in a very narrow band of wavelengths, making it a more efficient light source.

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LED is also a semiconductor, which implies that it can amplify light intensity and switch rapidly. This is an important quality to look for in a VLC light source because LiFi relies on the constant stream of photons emitted as visible light for the transfer of data. When the current applied to the light source is varied slowly, the light source dims up and down, which makes it unsuitable as a source of light, not for the LiFi system, but as a device for household illumination. To strike a balance between VLC light source and household illumination, this current as well as the optical output is modulated at extremely high speeds, making it detectable by the photodiode device and converted back into electrical current, but unperceivable by the human eye. Once these signals are received and demodulated, they can now be converted into a continuous stream of binary data that contain videos, images, audio, text, or applications that are readily-consumable on any internet-enabled device.

Because LiFi technology is still in its relative infancy, there is still much room for growing innovation. One proposed innovation to the existing technology includes creating a bidirectional communication system similar to conventional broadband and WiFi. This can be done by interchanging visible light and infrared light from a photodetector, allowing connected mobile devices to send back data to the light source for an uplink. Another proposed innovation is the re-engineering of the multi-colored RGB LEDs to send and receive data on a wider range of signals than the single-colored phosphor-coated white LEDs.

Advantages of Li-Fi

• Speed
• Efficiency
• More Secure
• High Availability

Drawbacks of Li-Fi

• Limited coverage area and can not penetrate walls like wifi
• Compatibility Issue (Present)

LiFi vs WiFi

S. No.	Term	Wi-Fi	Li-Fi
1	Full Form	Wireless Fidelity.	Light Fidelity.
2	Invented	by NCR corporation on 1991.	by Harald Haas from the University of Edinburgh, Scotland in 2011.
3	function	transmits data using radio waves using WiFi router or access point	transmits data using light signals using LED bulb or infrared light source.
4	Device Compliance	WLAN 802.11/b/g/n/ac/ad/ax standard compliant devices.	IrDA compliant devices.
5	Data Transfer Speed	WiFi transfer speed ranges from 150 Mbps to 3.5 Gbps.	Li-Fi can theoretically transmit at speeds of up to 100 Gbit/s.
6	Frequency	2.4Ghz, and 5Ghz. In the future, 802.11ax technology will also be available in the 6 GHz band as part of Wi-Fi 6E.	10,000 times radio frequency spectrum.
7	Distance Coverage	WiFi coverage area is upto 46 meters (150 feets).	LiFi coverage area is about 10 meters. Li-fi signals can not penetrate walls like Wi-Fi
8	Components	Routers, Modems and access points.	LED bulb, LED driver and photo detector.
9	Applications	Used in web browsing, HD streaming, download music, etc., using WiFi hotspot.	Used in under water communications and intelligent transportation systems