Li-Fi (Light Fedility)
Li-Fi is a wireless communication technology. It’s up to 100 times faster than standard Wi-Fi. It utilizes light to transmit data and position between devices. It is capable of transmitting data at higher speed over visible light, ultraviolet, and infrared spectrum. It is wireless optical networking technology which uses LEDs for transmission of data. Li-Fi is considered as light-based Wi-Fi in which it wi-fi uses radio waves to transmit information instead of light.

How does Li-Fi technology work?
Li-Fi uses light from LED lamps to transmit data to a device (laptop or tablet). The device has a receiver to receive light signals and a transmitter to transmit light signals back to the lamp by using infrared light. The light signal from the LED lamps changes the intensity billions of times faster than the eye can see. The change in intensity becomes a digital signal which can carry information from the internet and back again. Multiple lights can also be added to a single network so that you can move around light to light without losing connection. The digital signal can also be carried by light reflected off walls and other surfaces so you don’t have to be directly under a lamp to use Li-Fi. It still needs a regular internet provider to supply internet to home or offices via wires. Li-Fi can also be deployed within home or office to provide wireless internet connection to devices.
Advantages of Li-Fi:
• High data speed-The data transfer rate for internet application is higher.
• High security-provides high amount of security as data communication in line of sight (LOS).
• Low power- Li-Fi devices consumes low power for operation.
• RF spectrum saving-Uses optical spectrum so it avoids already crowded RF spectrum.
• Less harmful to humans-No health concerns in Li-Fi system as it operates on optical spectrum.
• It is easy to install.
Disadvantages of Li-Fi:
• LOS operation-Internet can be used only where light of source is available. Light cannot penetrate from walls and it works only in LOS path.
• Shorter range-limits the access of internet where everyone requires, moreover its range is limited.
• Inference from sunlight-cannot be used in outdoor like RF signal because the inference caused by sunlight and other optical sources.
• Requires light as medium-To avail Li-Fi internet services lights should be kept ON throughout day and night .
• Higher initial cost
Applications of Li-Fi:
• Street and traffic light
• Under water scenarios