lifi technolgy
TRANSCRIPT
Hamdard Institute of Engineering Sciences & Technology
Presented ByRasim Izhar Ali BECS/S13/0109Murad Ali JamaliBECS/S13/0106
Table of Contents• What is Li-fi?• Introduction• History • Present Scenario• Issues of Using Radio Spectrum• Who can resolve this issue?• Principle of Li-Fi• Why Li-Fi use VLC?• Li-Fi Vs Wi-Fi• Applications Of Li-Fi.• Merits And Demerits• Conclusion
What is Li-fi(LIGHT FIDELITY)? Light based Wi-Fi Light is used instead of radio
waves to transmit information. Transceiver fitted LED lamps
acts like Wi-Fi modems. LED lamps can light a room as
well as transmit-receive information.
Sending data through a LED light bulb that varies in intensity faster than human eye can follow.
HistoryProfessor Harald Haas Prof. Harald Haas, from
university of Edinburgh in the UK is the founder of Lifi.
On 20th July 2011 he used a table lamp with an LED bulb to transmit a video of blooming flowers that was then projected onto a screen behind him. During the event he periodically blocked the light from lamp to prove that the lamp was indeed the source of incoming data.
Present Scenario Radio Spectrum is congested but the demand
for wireless data double each other. Data in the form of tera bytes travel every
week or month. Every one want to use wireless data but the
capacity is drying up resulting in different issues.
So, what can carry this excess demand in future
Issues Of Using Radio Spectrum
Spectrum is 10,000 times greater than that of radio frequency.
Light waves available everywhere.
Highly efficient since LED consumes less energy.
Cannot penetrate through walls. Hence data can be secured.
Principle of Li-Fi When LED is ON ,we transmit a digital signal 1 and if the LED is OFF , we transmit a digital signal 0.
Why Li-fi use Visible Light Communication?
Gama rays, X-rays , Ultraviolet rays are harmful for the human body. Infrared Rays are also dangerous due to eye safety regulation and can only be used with low power.Radio waves are expensive and they are less secure. Therefore, only Visible rays or visible light spectrum is left which is not harmful for humans.
Radio Waves
Infrared Rays
Visible Rays
Ultraviolet Rays X-Rays Gamma
Rays
Characteristics Wireless Fidelity Light Fidelity
Range 100 meters Based on LED
Power Consumption Medium Low
Cost Expensive in comparison with LiFi because it uses Radio Spectrum
Cheaper than Wifi because free band doesn’t need license and uses light
Security Moderate Secured Highly Secured
Data transfer rate Within MBPS Greater than GBPS
Medium Through which data transfer
Use radio Spectrum Use light as a carrier
Spectrum Range Radio Spectrum Range is less than visible light spectrum
Visible light spectrum is 10,000 times broader than Radio spectrum range
Applications of Li-Fi
Traffic Scenario:-• Lifi can be used to communicate
with the LED’s of cars.
• This might prevent accidents by exchanging information when the vehicles are too close.
• Using Lifi, street lights can be used to send information about the road condition of the car.
Home And Small Offices In home and small offices,
Li-fi can be used to communicate with the devices such as:
Laptops Internet access HD Video
Streaming Printer
Street Lamps & Ocean Beds
An Ocean Beds Li-Fi can even work under water where wifi fails. Communication between Naval becomes easy.
Street Lamps There are millions of Lamps deployed around the world. Each of these street lamps could be a free access point.
Merits & DemeritsMerits
Data rate greater than 10Gbps theoretically allowing HD film to be downloaded in 30 seconds.
Can be used everywhere even in RF areas, since light waves will not interfere with radio waves.
As light waves cannot penetrate through walls, hence data cannot be intercepted which results in providing secured communication
Mostly LED light bulbs are used which consumes less energy. Hence cost efficient.
Demerits A major challenge of Li-Fi is how
the receiving device will transmit back to receiver.
Data transmission can be easily blocked by any object placed in front of LED source.
Interferences from external light source like sunlight, in the path of transmission can cause interruption in the communication.
Conclusion Researchers are developing a micron size LED’s. 1000 micron sized LED can fit into an area required
by 1sq.mm large single LED. A 1sq.mm sized array of micron sized LED’s could
therefore communicate 1000x1000(i.e.) million times as much information as a single 1sq.mm LED.
Thus ,if Li-Fi technology can be put into practical use, every bulb can be used as an alternative to Wi-Fi hotspot.