What are the advantages and limitations of Li-FI over Wi-Fi? While throwing light on its functioning, discuss the main challenges in conversion of existing devices into Li-Fi enabled ones.

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 which are used in houses and offices.
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 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.
The technology promises to transmit data at terabits per second speeds that is more than 100 times the speed of Wi-Fi. Every LED bulb in a house or office can be converted as a hotspot to transmit data; 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; street lights can also be converted as wireless hotspots for data transmission.
Challenges:

• Conversion of existing devices into Li-Fi enabled ones
• Requirement of line of sight for communication and it also faces interference form external light sources like sun
• High installation costs until it becomes more commercial