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Li fi Technology

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Li fi Technology

  1. 1. CONTENTS ж ж ж ж ж ж ж ж ж ж ISSUES REGARDING RADIO SPECTRUM INTRODUCTION PRINCIPLE OF LI-FI TECHNOLOGY VISIBLE LIGHT COMMUNICATION CONSTRUCTION and WORKING OF Li-Fi COMPARISON BETWEEN LI-FI AND WI-FI FUTURE APPLICATIONS CHALLENGES FOR LI-FI CONCLUSION REFERENCES
  2. 2. ISSUES REGARDING THE USE OF RADIO SPECTRUM CAPACITY AVAILABILITY EFFICIENCY SECURITY
  3. 3. INTRODUCTION ж ж ж ж Light–Fidelity (Li-Fi) technology came into existence in 2011. The term was f irst used by Harald Haas in his TED Global talk on Visible Light Communication. In October 2011 a number of companies and industry groups formed the Li-Fi consortium, to promote high-speed optical wireless systems. Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over 500 megabytes per second using a standard white-light LED.
  4. 4. INTRODUCTION (contd..) ж It allows wireless communication without the use of radio waves, which can be dangerous in places like oil platforms, underwater and on planes ж Li-Fi can be thought of as a light-based Wi-Fi. HARALD HAAS
  5. 5. PRINCIPLE OF LI-FI TECHNOLOGY ж Heart of Li-Fi technology is high brightness LED‟s. ж The LED bulb will hold a micro-chip that will do the job of processing the data. ж The on-off activity of LEDs enables a kind of data transmission using binary codes. ж Switching on an LED is a logical „1‟;switching it off is a logical „0‟. ж A light sensitive device (photo detector) receives the signal and converts it back into original data.
  6. 6. fig(i)..Sending of data [2]
  7. 7. VISIBLE LIGHT COMMUNICATION ж ж Li-Fi is a faster and cheaper version of Wi-Fi, which is based on visible light communication (VLC). The visible light communication is a data communication technique using visible light between 400 THz and 800 THz as an optical carrier for data transmission.
  8. 8. WHY VLC ? Radio Waves ж ж ж Infrared Rays Visible Rays Ultraviolet Rays X- Rays Gama Rays 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. HENCE WE ARE LEFT WITH ONLY THE VISIBLE LIGHT SPECTRUM which is not harmful for humans .
  9. 9. Devices used in visible light communication ж ж ж Devices which are used for transmission purpose in VLC are visible light LED and fluorescent lamp. This technology uses fluorescent lamps to transmit signals at 10bit/s, or LED‟s for up to 500 Mbit/s. Devices which are used for reception purpose in visible light communication are photo diodes and image sensors.
  10. 10. CONSTRUCTION and WORKING OF Li-Fi ж ж ж ж Li-Fi is implemented using white LED light bulbs at downlink transmitter. By fast variations of the current, optical output can be made to vary at extremely high speeds. An overhead lamp fitted with an LED with signal processing technology streams data embedded in its beam at ultra high speeds to the photodiodes. A receiver dongle then converts the tiny changes in amplitude into an electrical signal, which is then converted back into a data stream & transmitted to a computer or mobile device.
  11. 11. fig(ii)..Working of Li-Fi [1]
  12. 12. fig(iii)..Illustration of data transfer in Li-Fi [3]
  13. 13. COMPARISON BETWEEN LI-FI AND WI-FI Sl.No Parameters Light Fidelity Wireless Fidelity 1 Speed for data transfer Faster transfer speed (>1 Gbps) Data Transfer speed (150 Mbps) 2 Medium through which Used Light as a carrier Used Radio spectrum data transfers occurs 3 Spectrum Range Visible light spectrum has 10,000 time Radio frequency spectrum range is broad spectrum in comparison to less than visible light spectrum. radio frequency 4 Cost Cheaper than Wi-Fi because free band Expensive in comparison to Li-Fi doesn’t need license and it use light. because its uses radio spectrum. 5 Network topology Point to point Point to point 6 Operating frequency Hundreds of Tera Hz (THz) 2.4 GHz
  14. 14. FUTURE APPLICATIONS ж ж ж ж Li-Fi can be used in sensitive areas such as aircraft for data transmission without causing interference. It can be used in places where it is difficult to lay optical fibres like operation theaters . In traffic scenario, Li-Fi can be used to communicate with the LED lights of cars and might alert drivers when other vehicles are too close so accident numbers can be decreased. It will improve conditions for those working in underwater oil rigs where radio waves can‟t propagate.
  15. 15. FUTURE APPLICATIONS(contd..) ж ж Thousands and millions of street lamps can be transferred to Li-Fi lamps to transfer data. It can be used in petroleum and chemical plants where other transmission or frequencies could be hazardous.
  16. 16. CHALLENGES FOR LI-FI ж ж ж ж Presence of Light is essential. Li-Fi requires line of sight. It is easily blocked by somebody simply walking in front of LED source. The grand vision: “LED lights with added microchips will let us transmit thousands of data streams in parallel, enabling us to access the Internet on smartphones wherever there is a light source”.[1]
  17. 17. CONCLUSION ж ж ж ж Researchers are developing micron sized LED . 1000 micron sized LED can fit into area required by 1sq. mm large single LED. A 1 sq.mm sized array of micron sized LED‟s could therefore communicate 1000×1000 (i.e. a million) times as much information as a single 1mm LED. Li-Fi consortium believes it is possible to achieve more than 10Gbps, theoretically allowing a high definition film to be downloaded in 30 seconds.
  18. 18. REFERENCES [1] NEW EPOCH OF WIRELESS COMMUNICATION: LIGHT FIDELITY Authors: Megha Goyal, Dimple Saproo, Asha Bhagarshra, Journal: International Journal of Innovative Research in Computer and Communication Engineering ISSN/EISSN: 23209798 23209801 Year:2013 Volume: 1 Issue: 2 http://ijircce.com/upload/2013/april/52_New%20Epoch.pdf [2] Li-Fi (Light Fidelity)-The future technology In Wireless communication http://www.ripublication.com/ijaer.htm [3] 'Li-Fi' provides a light bulb moment for wireless web - CNN.com
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