1. LIGHT FIDELITY
LI-FI
BY
SHUDHANSHU AGARWAL (EC-11)
Shri Ram Murti Smarak College of
Engineering
And Technology, Bareilly

2. CONTENTS
• INTRODUCTION TO LIFI
• HOW DOES IT WORKS?
• COMPARISON WITH WI-FI
• 4 ISSUES WITH RADIOWAVE
• ALTERNATIVE FOR RADIO WAVE
• APPLICATION OF LI-FI
• IS IT A PROVEN TECHNOLOGY?

3. INTRODUCTION TO LI-FI
• LI-FI IS A TECHNOLOGY THAT USES THE LIGHT
EMITTING DIODES TO TRANSMIT THE DATA
WIRELESSLY.
• LI-FI IS FAST AND CHEAP OPTICAL VERSION OF
WI-FI ,BASED ON VISIBLE LIGHT
COMMUNICATION(VLC).
• VLC IS A DATA COMMUNICATION
MEDIUM,WHICH USES THE VISIBLE LIGHT
BETWEEN 400 THz (780 nm) and 800 THz (375
nm) AS OPTICAL CARRIER FOR DATA
TRANSMISSION

4. A LI-FI ENVIRONMENT

5. WHO INVENTED IT ?
• THIS TECHNOLOGY WAS
INVENTED BY GERMAN
PHYSICIST HARALD HAAS , FROM
THE UNIVERSITY OF
EDINBURGH ,U.K .
• HE DEMONSTRATED IT IN THE YEAR
2012.

6. HOW DOES LI-FI WORKS?

7. • THE HEART OF THIS TECHNOLOGY IS A NEW
GENERATION HIGH BRIGHTNESS LED’S.
• THESE LED’S VARIES IN INTENSITY (THAT IS
GETS ON AND OFF) SO FAST THAT A HUMAN
EYE CANNOT DETECT IT.
• IF LED IS ON , THEN WE TRANSMIT A DIGITAL
SIGNAL 1,AND IF THE LED IS OFF , THEN WE
TRANSMIT A DIGITAL SIGNAL 0.
• A CONTROLLER IS CONNECTED AT THE BACK
SIDE OF THESE LED BULBS TO CODE DATA TO
THESE LED’S.

8. LIFI VS WIFI
 DATA TRANSFER SPEED
• Li-Fi has a High speed
data transfer rate over
1Gbps.
• Wi-Fi has a data
transfer rate of
maximum 54Mbps
•WHY SO MUCH DIFFERENCE?

9. • LI-FI HAS AN UPPERHAND DUE TO PARALLEL
DATA TRANSMISSION.

10. LI-FI VS WIFI (CONTD…)
PART OF EM
SPECTRUM THEY USE
• LI-FI USES THE
VISBLE LIGHT
PORTION OF THE EM
SPECTRUM
• WIFI USE THE
RADIOWAVE
PORTION OF THE EM
SPECTRUM

11. ISSUES WITH RADIO WAVE
 CAPACITY
• WITH THE ADVENT OF NEW TECHNOLOGIES
LIKE 3G ,4G WE ARE RUNNING OUT OF
SPECTRUM.
• THAT’S WHY RADIO WAVES ARE NOW
BECOMING EXPENSIVE.

12. EFFICIENCY
• THERE ARE 1.4 MILLIONS CELLULAR RADIO
BASE STATIONS .
• EFFICIECY OF EACH BASE STATION IS JUST 5%.
• MOST OF THE ENERGY IS NOT USED FOR
TRANSMISSION BUT RATHER FOR COOLING
DOWN THE BASE STATION.

13. SECURITY
• RADIO WAVES CAN PENETRATE THROUGH
WALLS AND HENCE CAN BE INTERCEPTED.
• ANYONE WITH KNOWLEDGE AND BAD
INTENTION CAN MISUSE IT.
AVALILABLITY
• WE HAVE TO SWITCH OFF MOBILES IN
AIRCRAFTS.
• IT IS ALSO NOT ADVISABLE TO USE MOBILES
AT PETROL PUMPS.

14. ALTERNATIVE OF RADIO WAVES
CAN IT BE INFRARED WAVES ? NO
IR WAVES ARE HARMFUL FOR OUR EYES HENCE USED TA VERY LOW POWER

15.  CAN IT BE UV RAYS? NO
• UV RAYS ARE HARMFUL FOR OUR SKIN AND
CANNOT BE USED FOR LONG DURATION.
 CAN IT BE GAMMA RAYS ? NO
• GAMMA RAYS ARE RADIOACTIVE AND ARE
DANGEROUS.
 CAN IT BE X-RAY S ? NO
 SO WE ARE LEFT ONLY WITH VISIBLE LIGHT
SPECTRUM.

16. OVERCOMING THE FOUR ISSUES
WITH RW IN LI-FI
1. CAPACITY
• 10000 TIMES MORE SPECTRUM THAN RW.
LIGHT BOXES ARE ALREADY PRESENT, SO
INFRASTRUCTURE IS AVAILABLE ALREADY
AND INSTALLED.
2. EFFICIENCY
• HIGHLY EFFICIENT BECAUSE LED CONSUMES
LESS ENERGY.

17. 3. AVAILABLITY
• LIGHT IS PRESENT EVERYWHERE.
• DATA IS PRESENT WHERE LIGHT IS PRESENT.
4. SECURITY
• LIGHT WAVES DOESNOT PENETRATE
THROUGH WALLS.
• HENCE THEY CAN’T BE INTERCEPTED.

18. ADVANTAGES OF LI-FI
• YOU CAN USE LI-FI IN HOSPITALS AND
AIRCRFTS ALSO.
• CHEAPER THEN WIFI , SINCE VISIBLE LIGHT
SPECTRUM IS A FREE SPECTRUM BAND.
• NO LICENSE NEEDED.
• THOUSANDS AND MILLIONS OF STREET
LAMPS CAN BE COVERTED TO LI-FI SPOTS.

19. IS THIS A PROVEN TECHNOLOGY ?
• YES THIS ALREADY PROVEN.
• HARALD HAAS DEMONSTRATED HIS
INVENTION USING AN ORDINARY TABLE
LAMP THAT SUCCESSFULLY TRANSMITTED
DATA AT SPEEDS EXCEEDING 10Mbps USING
LIGHT WAVES FORM LED LIGHT BULBS TO A
COMPUTER LOCATED BELOW THE LAMP.TO
PROVE THAT THE LIGHT WAS THE SOURCE OF
THE DATA STREAM HE PERIODICALLY
BLOCKED THE BEAM OF LIGHT , CAUSING THE
CONNECTION TO DROP.

20. THANK YOU