What is Li-Fi Technology?

• Wi-Fi, the technology that has become a sort of oxygen that allows us to survive in an interconnected world, could be overcome soon. 
• While its use will not disappear, at least for now because it will shift to the background in favor of technological development, which will soon present a new connection system: Li-Fi.

Li-Fi Network

What is Li-Fi Technology?

• Li-Fi-light fidelity is similar to Wi-Fi technology and it is one of the future of wireless communication technologies. 
• The main feature of this technology includes fully networked, bidirectional and high-speed wireless. 
• Nowadays, the most trending domain in wireless communication is Wi-Fi and internet users are also being increased every year. 
• For obtaining better speed, efficiency, bandwidth, Li-Fi technology has evolved. 
• In this technology data transmission can be done using light because the light intensity changes quicker than the human eye. 
• The transmission speed of data in Li-Fi is faster 100 times than Wi-Fi.

Block Diagram of Li-Fi System

• Li-Fi system mainly includes two parts namely the transmitter and receiver. The input signal at the transmitter section can be modulated with a specific time period then send the data using LED bulbs in 0’s and 1’s form. 
• At the receiver end, a photo diode is used to receive the LED flashes strengthens the signal & gives the output.
• The block diagram of Li-Fi system is shown below, and the transmitter section includes the input, timer circuit, an LED bulb. 

• The input of the transmitter can be any kind of data like text, voice, etc. 
• The timer circuit in this section is used to provide the necessary time intervals among every bit, and these are transmitted to the receiver end in the form of LED flashes. It all done for security purposes.
• The receiver section includes photo-diode as well as amplifier. Here, photo-diode receives the LED bulb flashes then changes the flashes into electrical signals. 
• Finally, the amplifier receives the signals from the photo-diode and amplifies to provide the output.

How Li-Fi Works?

• Li-Fi is a VLC (visible light communications) system and the speed of this system is very high. 
• Li-Fi uses normal LEDs to allow the data to transfer and increase the speed up to 224 Gigabits/sec. 
• The data transmission of this technology can be done via illumination. The essential devices of this system are the bright light emitting diodes.
• The ON/Off activity of LEDs permits a type of data transmission in the form of binary codes but the human eye cannot recognize this transform & the bulbs appear with a stable intensity.

Differences between Li-Fi & Wi-Fi

• The Bandwidth Expansion of Wi-Fi technology is limited and exceptional for Li-Fi
• The Speed of the Wi-Fi is150 Mbps and >10 Gbps for Li-Fi
• The Data Density of Wi-Fi technology is low and high for Li-Fi
• The Range of Wi-Fi is medium and low for Li-Fi
• The Security of Wi-Fi is medium and excellent for Li-Fi
• The power availability of Wi-Fi is low and high for Li-Fi
• The ecological impact of Wi-Fi is medium and low for Li-Fi
• The cost of the Wi-Fi is medium and low for Li-Fi
• The network topologies of Li-Fi and Wi-Fi technologies is a point to point

Advantages of Li-Fi

• Speed-The speed of the Li-Fi is very high, and we can watch the videos without buffering.
• Security- The light of the Li-Fi doesn’t run through the partition, therefore, it is more protected and hacking is not possible.
• Risk-free-Li-Fi utilizes light waves which are harmless.
• Consistent- The data transfer is more protected.

Disadvantages of Li-Fi

• Apart from several benefits, the Li-Fi technology is facing several problems. It requires LOS (line of sight), as well as the receiver.
• The main problem is how the receiver will send the data back to the transmitter section.
• Another disadvantage of this technology is "sunlight in the lane of communication will cause intermission in the transmission".
• It doesn’t work in the dim areas.

Li-Fi Technology Applications

• Traffic Management & Road Safety
• Medical Applications
• Aviation
• Communication Underwater
• Elegant Lighting
• Interior map-reading system for blind people
• In dangerous Environments or In Sensitive regions
• Transportation
• Industrial Areas

Li-Fi technology vs Wi-Fi technology

• Li-Fi is a great improvement compared to Wi-Fi at all levels. 
• Li-Fi signals cannot pass through walls, so in order to enjoy full connectivity, capable LED bulbs will need to be placed throughout the home.
• To begin with, the transmission speed is up to 100 times faster.

COMPARISION	LI-FI	WI-FI
Full form	stand for light fidelity	stands for wireless fidelity
Invented/Coined	Coined by Prof. Harald Haas in 2011	By NCR corporation on 1991
Operation	it transmits data using light by the help of LED bulbs	it transmits data using radio waves using wifi router
Technology	Present IrDA compliant devices	WLAN 802.11/b/g/n/ac/d standard compliant devices
Data Transfer Speed	About 1 Gbps	Ranges from 150Mbps to maximum of 2Gbps
Privacy	light is blocked by the walls hence provide more secure data transfer	walls cannot block radio waves so we need to employ more techniques to achieve secure data transfer
Frequency of operation	10, 000 times frequency spectrum of the radio	2.4Ghz, 4.9Ghz and 5Ghz
Coverage Distance	about 10 meters	about 32 meters(vary based on transmit power and antenna type)
Data density	work with high dense environment	work in less dense environment due to interference related issues
Bare minimum Components used	LED bulb, LED driver and photo detector	Routers, Modems and access points
Applications	Used in airlines, undersea exploration etc	Used for internet browsing with the help of wi-fi hotspot