Li-Fi, or "light fidelity," is a wireless communication technology that utilizes LED light to transmit data through varying light intensities, aiming to alleviate congestion in the radio spectrum as demand for wireless data grows. Originating in the 1990s, Li-Fi can achieve rapid data transmission rates and has various applications, including transforming streetlights into data hotspots and enabling underwater communication. However, the technology faces limitations such as high installation costs, the need for line-of-sight for transmission, and challenges in two-way communication.

1. LI-FI TECHNOLOGY
ONKAR BHUJBAL
Roll No-27
Div –TE(A)
S.R. PAWARA

2. CONTENTS
 INTRODUCTION
 HISTORY
 PRESENT SCENARIO
 ISSUES REGARDING RADIO SPECTRUM
 VISIBLE LIGHT SPECTRUM
 HOW LIFI WORKS
 CONSTRUCTION OF LIFI
 COMPARISON OF LIFI WITH WIFI
 APPLICATIONS
 LIMITATIONS
 CONCLUSION
 REFERENCES

3. INTRODUCTION
 Li-fi basically known as “LIGHT FEDILITY”
 The basic ideology behind this technology is that the data can be transmitted
through LED light whose intensity varies even faster than the human eye.
 Li-Fi is the term some have used to label the fast and cheap wireless-
communication system
 As there are more and more devices coming up day-by-day the signals are
being clogged up due to heavy traffic, there a need for an error free transmission
technology.

4. history
 The technology truly began during the 1990's in countries like
Germany, Korea, and Japan where they discovered LED's could be
added to send information.
 At TED Global Talk, Haas demonstrated a data rate of transmission
of around 10Mbps.
 German scientists succeeded in creating an800Mbps (Megabits per
second) capable wireless network by using nothing more than
normal red, blue, green and yellow LEDS.
 In October 2011 a number of companies and industries formed the
Li-Fi Consortium, to promote high-speed optical wireless system to
enhance the limited bandwidth provided by radio-based wireless
spectrum available.

5. PRESENT SCENARIO
1.4 Million Base Stations 5 Billion Devices

6. PRESENT SCENARIO
 Radio Spectrum is congested but the demand for wireless data
double each year .Every thing, it seems want to use wireless
data but the capacity is drying up.
 So what can carry this excess demand in the future .

8. Capacity :
 We transmit wireless data through radio waves.
 Radio waves are limited.
 Radio waves are scar and expensive.
 We only have a certain range of it.
 With the advent of the generation technology as of like of 2.5G,3G,4G and so
on we are running out of spectrum.
Efficiency :
 There are 1.4 million cellular radio base stations
 They consume massive amount of energy
 Most of this energy is not use for transmission but for cooling down the base
stations
 Efficiency of such a base station is only 5% and that raise a very big problem

9. Availability :
 Availability of radio waves causes another concern.
 We have to switch off our mobiles in airplanes.
 It is not advisable to use mobiles at places like petrochemical plants ,hospitals
petrol pumps.
Security :
 Radio waves penetrates through walls
 They can be intercepted
 If someone has a knowledge and bad intentions then he may misuse it

10. Radio
Waves
Infrared
Rays
Visible
Rays
Ultra
Violet
Rays
X-Rays
Gamma
Rays
 Gama rays cant be used as they could be dangerous.
 X-rays have similar health issues.
 Ultraviolet light is good for place without people, but other wise
dangerous for the human body.
 Infrared, due to eye safety regulation, can only be used with low power.
 Radio waves are limited bandwidth, expensive and less secure.
FIG-Electromagnetic Spectrum

12. How LI-FI Works ?

13.  On one end all the data on the internet will be streamed to a lamp
driver when the led is turned on the microchip converts the digital
data in form of light.
 The LED lamp will hold a microchip that will do the job of
processing the data.
 A light sensitive device (photo detector) receives the signal and
converts it back into original data.

14. Figure- Architecture Of Li-Fi

15.  An RF (radio-frequency) signal is generated by the solid-state
PA and is guided into an electric field about the bulb.
 The PCB controls the electrical inputs and outputs of the lamp
and houses the microcontroller used to manage different lamp
functions.
 The high concentration of energy in the electric field vaporizes
the contents of the bulb to a plasma state at the bulb’s centre ;
this controlled plasma generates an intense source of light
CONSTRUCTION
The LIFI product consists of 4 primary sub-assemblies:
• BULB
• RF power amplifier circuit (PA)
• Printed circuit board (PCB)
• Enclosure

18. APPLICATIONS OF LIFI

19.  There are millions of street lamps deployed around the world.
 Streets lamps can be transferred to lifi lamps to transfer data.
 Each of these street lamps could be a free access point.
PUBLIC INTERNET
HOTSPOTS

20. TRAFFIC LIGHTS
 Traffic lights can communicate to the car and
with each other.
 Cars have LED-based headlights, and cars
can communicate with each other and prevent
accidents in by exchanging information.

21. ON OCEAN BEDS
 Li-Fi can even work underwater were Wi-Fi fails
completely, thereby throwing open endless
opportunities for military/navigation operations.

22.  Visible Light is more safe than RF.
 Hence it can be used in places such as
petrochemical plants, Hospitals, Airlines
where RF is restricted.
SAFE ENVIRONMENT

23.  High installation cost of the VLC systems.
 A major challenge facing Li-Fi is how the receiving device will transmit
back to transmitter.
 Light can't pass through objects.
 Requires line of sight to transmit data.
LIMITATIONS

24. CONCLUSION
The possibilities are numerous and can be explored
further. If this technology can be put into practical use ,
every bulb can be used something like a Wi-Fi hotspots
to transmit wireless data.

25. REFERENCES
 Wikipedia
 http://lificonsortium.org/
 http://gimt.edu.in/clientFiles/FILE_REPO/2012/NOV/23/1353645362
045/69.pdf
 https://www.youtube.com/watch?v=WRG9iXZbuAc