3. Li-Fi
Light based Wi-Fi.
Uses Transciever fitted Led’s instead of
modems used in Wi-Fi.
Transmission of data through illumination.
4. Discovery
Research work started in 1990’s in countries like
Japan , Russia and Korea.
In 2011, Harald Hass demonstrated a data
transmission rate of 10 mbps(comparable to a
fairly good UK broadband connection) at
TEDGlobal and later achieved speed of 123
mbps.
German scientist achieved speed of 800 mbps
using nothing but blue ,red , yellow and green
led’s.
5. Need For Li-Fi
1.4 billion 5 billion
• Radio Spectrum
Congestion
• Issues
• Speed
6. Overcoming Wi-Fi Issues
Capacity-Spectrum is 10,000 times stronger
than radio-waves.
Efficiency-Highly efficient as LED consumes
lesser power
Availability-Light waves available
everywhere.
Security-Cannot penetrate through walls ,
hence data cannot be penetrated.
7. Operational procedure is simple!
If LED is ‘ON’ digital data ‘1’ is transmitted
& if LED is ‘OFF’ digital data ‘0’ is
transmitted.
Controller connected at backside of led is
used to code the data.
It is also known as 5G optical
communication.
8. Implementation
• All data from internet is
streamed into lamp driver.
• Data decides how much the
intensity of LED is to be
varied.
• By fast & subtle variation of
current optical o/p will vary
at high speeds.
• Photodetector picks up the
signal.
• Receiver dongle converts
light into data streams.
9. VS
Characteristics Wi-Fi Li-Fi
Standard IEEE 802.11 IEEE 802.15
Range 100 m Based on LED
light
Cost Medium High
Data transfer
rate
800 kbps-11
mbps
> 1Gbps
Power
consumption
Medium Low
Security Medium High
11. Traffic
• Li-Fi can be used to communicate
with the LED lights of cars.
• Cars have LED based headlights,
backlights and can communicate
with each other.
• This might prevent accidents by
exchange of information when the
vehicles are too close.
• Using Li-Fi, Street lights can be
used to send information about
the road condition to the car.
12. Lectures/Seminar Halls
• Download notes from blogs of
teacher.
• Interactive classrooms with
interconnected devices.
• Sharing of views & queries with entire
class.
13. Industries
Used in RF restricted
environments such as
chemical industries, nuclear
power plants, petrol pumps.
14. Aircrafts
• Whole airways communication is
done using radio-waves.
• Hence passengers face the
problem in communication.
• This problem can be overcome
using Li-Fi, since light waves will
not interfere with radio waves.
15. Advantages
Data rate greater than 10 Gbps; theoretically
allowing HD movie download in 30 seconds.
Can be used in RF restricted areas.
Cost efficient as LED’s consume less power.
Secured communication.
Quick and reliable.
16. Limitations
Visible light cannot penetrate through solid
objects.
Interference by external light rays can cause
interruptions.
Data transmission can be easily blocked by
any object placed in front if the LED.
A major challenge of Li-Fi is how the receiving
device will transmit back to the transmitter.
17. Conclusion
Thus, if Li-Fi is put into practical use, every
bulb can be used as an alternative to Wi-Fi
hotspots. It provides simple, faster and
efficient wireless data communication. Li-Fi
will make us proceed towards the cleaner,
safer, greener and brighter future.
