Li-Fi , 100x Faster Than Wi-Fi. Li-Fi looks to be yet another disruptive technology, this time in communication, which has remained with the same wireless technology since the year 2000.

1. Li-Fi Technology
Presented by
 Toufa Rani Saha
 Abida Sultana
 MD. Raihanur Rahman
 Mehedi Hasan

2. What is Li-Fi ?
• Full meaning of Li-Fi is “Light Fidelity”
• Li-Fi is transmission of data through illumination, sending data through LED
• Li-Fi is a bidirectional, high-speed and fully networked wireless
communication technology similar to Wi-Fi

3. Characteristics of Li-Fi
• Light based Wi-Fi
• Like Wi-Fi, Li-Fi is wireless and uses similar 802.11 protocols; but it uses visible light
communication
• Transceiver fitted LED lamps acts like Wi-Fi modems

4. History of Li-Fi Technology
• Professor Harald Haas, introduces the term "Li-Fi" at his 2011 TED Global Talk where
he introduced the idea of "Wireless data from every light“
• Later 2011, a number of companies offer uni-directional VLC products, which is not
the same as Li-Fi - a term defined by the IEEE 802.15.7r1 standardization committee
• In April 2014, the Russian company Stins Coman announced the development of a
Li-Fi wireless local network called BeamCaster
• In 2014 a new record was established by Sisoft (a Mexican company) that was able
to transfer data at speeds of up to 10 GB/s across a light spectrum emitted by LED
lamps

5. Radio Spectrum Issues
 capacity:
• radio-waves, cost & expensive
• Less bandwidth compared to others
 availability:
• available within the range of base-station
• limited availability
• unavailable in aircrafts
 security:
• less secure
• passes through walls

6. Electromagnetic spectrum & VLC
• Electromagnetic Spectrum figure –

7. Why VLC is more preferable ?
 from the electromagnetic spectrum:
• Gamma Rays are dangerous
• X-Rays, Ultra Violate (UV) lights also have similar health issues
• Infrared can only be used in low power due to eye safety regulation
So, we have only Visible Light Area is left. And from above discussion, we can safely
use VLC or Visible Light Communication system and it is more safer and preferable
than others.

8. Working Process
• Operational procedure is very simple
• When the LED is on, it transmit the
digital 1. and when the LED is off, it
transmit the digital 0
• It required some LEDs and a controller
that code data into those LEDs
• Flicker depending upon the data we
want to encode
• Thus every light source will work as a
HUB for data transmission

9. Working Process
• On one end all data will be streamed
to a lamp driver.
• When the LED is turned on, the
microchip converts the digital data in
light form
• A light sensitive device (photo
detector) receives the signals and
converts it bck into original data
• This method of using rapid pulses of
light to transmit information wirelessly
is technically referred as VLC or Visible
Light Communication

10. Working Process

11. Comparison Between Li-Fi and Wi-Fi
• Li-Fi is thought as Light Based Wi-Fi. It
uses light instead of radio-wave
• Instead of Wi-Fi modems it uses
transceiver-fitted LED lamps, that can
light a room as well as transmit and
receive information
• Wi-Fi is great for general wireless
coverage within buildings and Li-Fi is
ideal for high density wireless data
coverage and for relieving radio
interference issues

12. Comparison Between Li-Fi and Wi-Fi
Light Fidelity (Li-Fi)
Faster transfer speed ( > 1 Gbps )
Use light as carrier
Visible light spectrum has 10,000 time
broad spectrum in comparison to radio
frequency
Cheaper than Wi-Fi because free band
doesn’t need license and it uses lights
Point to Point network topology
Operating frequency is Hundreds of
Tera Hz
Wireless Fidelity (Wi-Fi)
Data transfer speed is near to 150
Mbps
Use radio spectrum
Radio frequency spectrum range is less
than visible light spectrum
Expensive in comparison to Li-Fi
It is also Point to Point
Operating frequency is near to 2.4 GHz

13. Application of Li-Fi Technology
 Traffic Lights:
• Traffic lights can communicate to
the car and with each others
• Cars have LED based headlights
and back lights. And they can
communicate with each others
and prevent accidents by
exchanging informations

14. Application of Li-Fi Technology
 Airlines:
• The whole airways
communication is performed on
the basis of radio-wave, that’s
why when we travel we face the
problem with communication
medium
• To overcome this drawback, Li-FI
technology is introduces
• And it is safer in airways

15. Application of Li-Fi Technology
 Under Sea Areas:
• Li-Fi can even work in underwater
where Wi-Fi fails completely
• Because light can pass through
water
• There are great and endless
opportunities for
military/navigation operations by
using Li-Fi technology

16. Application of Li-Fi Technology
 Street Lamps:
• There are millions of street lamps
around the world
• Each of these lamps could be free
access points

17. Limitations of Li-Fi technology
 Though having many advantages, this technology has some limitations
• Light can’t pass through objects
• Li-Fi requires line of sight
• High installation cost of VLC system
• A major challenge of this technology is how the receiving device will transmit
back to transmitter
• Interference from external light sources like sunlight, in the path of
transmission will cause interruption in the communication