Top Banner
Hamdard Institute of Engineering Sciences & Technology Presented By Rasim Izhar Ali BECS/S13/0109 Murad Ali Jamali BECS/S13/0106
18
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
  1. 1. Hamdard Institute of Engineering Sciences & Technology Presented By Rasim Izhar Ali BECS/S13/0109 Murad Ali Jamali BECS/S13/0106
  2. 2. 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
  3. 3. 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.
  4. 4. History Professor 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.
  5. 5. Present Scenario 1.4 Million Base Stations 5 Billion Mobile Stations
  6. 6. 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
  7. 7. 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.
  8. 8. Who can resolve this issue?
  9. 9. 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.
  10. 10. Working Principle of Li-Fi
  11. 11. 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
  12. 12. 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 doesnt 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
  13. 13. Applications of Li-Fi Traffic Scenario:- Lifi can be used to communicate with the LEDs 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.
  14. 14. 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
  15. 15. 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.
  16. 16. Merits & Demerits Merits 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.
  17. 17. Conclusion Researchers are developing a micron size LEDs. 1000 micron sized LED can fit into an area required by 1sq.mm large single LED. A 1sq.mm sized array of micron sized LEDs 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.
  18. 18. Thank You THANK YOU