Presentation on Light Fidelity( Li-Fi).

1. LI-FI : LIGHT FIDELITY
Presentation By:
Ashish Agarwal
ECE 3nd
Year

2. CONTENTS
• What is Li-Fi?
• Why is it required?
• LiFi over WiFi
• Working
• Advantages
• Disadvantages
• Applications

3. Li-Fi, as coined by Prof. Harald Haas (in TED Global
talk), is bidirectional, high speed and fully networked
wireless communications similar to Wi-Fi.
Li-Fi is a subset of optical wireless communication (OWC)
and can be a complement to RF communication (Wi-
Fi or Cellular network), or a replacement of data
broadcasting.
WHAT IS LI-FI?

4. Brain Behind LI-FI
Prof. Harald Haas
He is Professor of Mobile Communications at the University of Edinburgh

6. Existing wireless technology - Why
do we need an alternate
technology?
• CAPACITY
• EFFICIENCY
• AVAILABILITY
• SECURITY

8. VISIBLE SPECTRUM

10. LI-FI OVER WI-FI

11. WORKING
• In LED bulbs the current, and hence the optical output,
can be modulated at extremely high speeds which can be
detected by a photo-detector device and converted back
to electrical current.
• Sending data through a LED light bulb that varies
intensity faster than human eye can follow.
• Using this technique, high speed information can be
transmitted from an LED light bulb.

13. • 100 times faster than Wi-fi.
• Securest way of data transfer till date .
• Unlike Wi-fi, has no bandwidth and spectrum crisis
and limitations : light spectrum is 10,000 times larger
than the RF spectrum.
• Cause no harm to Health.
• Requires fewer components than radio technology.
• LED illumination is already efficient and the data
transmission requires negligible additional power.
ADVANTAGES

14. • Can be used in electromagnetic- sensitive areas like
flights and nuclear power plants.
• No direct contact needed: light reflected off the walls can
reach speeds of 70Mbits/sec.
• Very high data rates can be achieved due to low
interference, high device bandwidths and high intensity
optical output.
ADVANTAGES

15. APPLICATIONS
• Underwater communications: Since radio waves cannot be used
under water because these waves are strongly absorbed by sea water
within feet of their transmission and this renders it unusable
underwater but LI-FI is suitable for underwater communication
• Health sector: Since WIFI is not safe to be used in hospitals and
other various health care sectors because it penetrates human body.
LIFI can be implemented and well suit in this sector.
• Internet anywhere: street lamps, light of vehicles can be used to
access internet anywhere in footpaths, roads, malls, anywhere where
light source is available.
• Safety and management: it can be used to update traffic
information at almost every instant and it will be easy for traffic
police to deal with traffic and catch the one who breaks the rule.

16. APPLICATIONS
• Aviation: Li-Fi can be used to reduce weight and cabling and add
flexibility to seating layouts in aircraft passenger cabins where LED
lights are already deployed. In-flight entertainment (IFE) systems
can also be supported and integrated with passengers’ own mobile
devices.
• Location Based Services (LBS): Highly accurate location-specific
information services such as advertising and navigation that enables
the recipient to receive appropriate, pertinent information in a timely
manner and location.

17. DISADVANTAGES
•These signals cannot penetrate walls. So the person needs
wired to that source.
• The disadvantage of the Lifi is uplink is difficult.
• So we can have the photodiodes embedded near to the people on
the pillars for eg.
• Or we can have the same led behaving as a photodiode as well as
an LED.

18. 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.
CONCLUSION

19. REFERENCES
• www.purelifi.com/
• Wikipedia
• Slideshare
• www.youtube.com

20. Thank You!

21. ANY QUERY ?