PowerPoint Presentation

AMERICAN UNIVERSITY OF SCIENCE & TECHNOLOGY

Light Fidelity

PRESENTED TO: Dr. ROGER ABOU JAOUDEPresented By:Maryam KatayaHassan HarajliMohamMad wehbe Bahaa ghaddarTarek hniEdiElias kawkabani1OUTLINEWhy Li-Fi?Usage of the EM SpectrumWhat is Li-Fi?Li-Fi DiagramLi-Fi ConceptApplicationsLi-Fi vs. Wi-FiDisadvantagesConclusionReferences

2Why Li-Fi ?Availability: Today, we have more than 1.4 million base stations and more than 5 billion mobile phones. Plus you have to switch off your mobile phone in certain areas.Capacity: Radio waves are limited, expensive and the capacity does not cope with data transmission demands; we are running out of spectrum.Efficiency: Base Stations consume a lot of energy, most of which is used to cool the base station and so little is used to transmit. Therefore the efficiency of the base station is about 5%.Security: Radio waves penetrate through walls and can be intercepted easily. 3

Usage of EM Spectrum4Usage of EM SpectrumLight is part of the EM Spectrum.Light has been around for millions of years and it is safe to use.Compared with the radio spectrum, Visible light spectrum is 10,000 times bigger.

5What is Li-Fi ?Li-Fi is transmission of data through illumination by taking the fiber out of fiber optics by sending data through a LED light bulb that varies in intensity faster than the human eye can follow.The term was first used in this context by Harald Haas in his TED Global talk on Visible Light Communication. If the LED is on, you transmit a digital 1, if its off you transmit a 0; OOK.They can be switched on and off very quickly, which gives nice opportunities for transmitted data. It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s.

6Li-Fi Diagram7Li-Fi ConceptWhen a constant current is applied to an LED light bulb a constant stream of photons are emitted from the bulb which is observed as visible light. If the current is varied slowly the output intensity of the light dims up and down. Because LED bulbs are semi-conductor devices, 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. The intensity modulation is imperceptible to the human eye, and thus communication is just as seamless as RF. Using this technique, high speed information can be transmitted from an LED light bulb.8

Li-Fi ConceptMixtures of red, blue, green LEDs are also used by some groups to encode different data channels by altering the light frequencies.Simply if you are receiving the light means you are connected and if you block it off you are simply offline. the data could be received in familiar forms of waves like visible light, infrared or ultraviolet and thus the future possibilities are many.It is implemented by using a light bulb at the downlink transmitter. Normally the light bulb glows at a constant current supply however fast and subtle variations in current can be made to produce the optical outputs since it just uses the light, hence can be easily applied in aircrafts or hospitals or any such area where radio frequency communication is often problematic.

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10Source: Li-Fi LAB StoreApplicationsAirlinesPower plantsUnder sea workingInformation delegationCan be used effectively in the places where it is difficult to lay the optical fiber cableIn operation theatres Li-Fi can be used for modern medical instrumentsIn traffic signals Li-Fi can be used to communicate with the LED lights of the cars.

11Li-Fi vs. Wi-FiS. No.ParameterLi-FiWi-Fi1SPEEDUp to 10 Gb/s *Around 150Mb/s2Medium of data transferUse light as carrierUse radio spectrum3Spectrum rangeVisible lights has 10000 times moreHaving less spectrum range than VLC4CostCheaperExpensive5 Network topologyPoint to PointPoint to Point6Operating frequencyHundreds of THz2.4GHz12*Siemens achieved 500 Mbps transfer rate*Pennsylvania State University achieved transfer rates of 1.6 Gb/s*SISOFT and Autonomous Technological Institute of Mexico (ITAM) achieved up to 10 Gb/sAdvantages of using Li-FiSafe to use10000x more spectrumCan yield a speed up to 10GbpsA very high reuse factorSecure communicationVery easy to deploy (Infrastructure ready)Light can be dimmed down to a level close to off and still transmits dataHighly energy efficient 13Disadvantages of using Li-FiNo vertical handover nor horizontal handover available yetlimited coverage (detectable up to 20m only)Light waves cannot penetrate wallsConnection can be easily interruptedExternal light Interference such as sun light14ConclusionThe possibilities of Li-Fi are numerous and can be explored further. The concept of Li-Fi is currently attracting a great deal of interest, not least because it may offer a genuine and very efficient alternative to radio-based wireless. The use of Li-Fi would solve many issues regarding the shortage of radio-frequency bandwidth and also allow internet where traditional radio based wireless isnt allowed such as aircraft or hospitals.Li-Fi would guarantee a cleaner, safer and an eco-friendly environment.15Referenceshttp://www.lificonsortium.org/technology.htmlhttp://www.ripublication.com/irph/ijict_spl/ijictv4n16spl_11.pdfhttp://www.lifi.com/pdfs/techbriefhowlifiworks.pdfhttp://www.gizmag.com/li-fi-wireless-technology/32968/https://www.youtube.com/watch?v=NaoSp4NpkGg

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