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Li-Fi Technology

Li-Fi Technology. By Vinay kumar.I ( 0560482 ). Contents . Abstract Introduction Drawbacks Of Before Technologies Different Between The Technologies Working process Applications Advantages Concussion. WHAT IS LI – FI ?.

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Li-Fi Technology

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  1. Li-Fi Technology By Vinaykumar.I (0560482)

  2. Contents • Abstract • Introduction • Drawbacks Of Before Technologies • Different Between The Technologies • Working process • Applications • Advantages • Concussion

  3. WHAT IS LI – FI ? • LI-FI is transmission of data through illumination ,sending data through a LED light bulb that varies in intensity faster than human eye can follow

  4. HISTORY • The technology truly began during the 1990's in countries like Germany, Korea, and Japan where they discovered LED's could be retrofitted to send information.  Harald Haas continues to wow the world with the potential to use light for communication HARALD HASS

  5. PRESENT SCENARIO • Radio Spectrum is congested but the demand for wireless data double each year .Every thing, it seems want to use wireless data but the capacity is drying up. • So what can carry this excess demand in the future .

  6. PRESENT SCENARIO 1.4 Million 5 Billion

  7. Availability Capacity Efficiency Security

  8. WHO CAN REPLACE RADIO WAVES FOR WIRELESS COMMUNICATION ?

  9. How LI-FI Works ? Li-Fi means “Light Fidelity”. At the heart of this technology is a new generation of high brightness light-emitting diodes 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.

  10. WHY ONLY VLC • Gama rays cant be used as they could be dangerous. • X-rays have similar health issues. • Ultraviolet light is good for place without people, but other wise dangerous for the human body. • Infrared, due to eye safety regulation, can only bse used with low power. • HENCE WE LEFT WITH THE ONLY THE VISIBLE - LIGHT SPECTRUM.

  11. LUXIM • LUXIM is a privately owned clean tech company based in Sunnyvale, California which was founded in 2000.

  12. Luxim Product’s (li-fi) • Luxim offers three unique products for use in technical lighting. LIFI4KP is intended for visible light applications including general microscopy, machine vision, and inspection. LIFI4KT is a broadband source that includes both UVA and visible region of the spectrum. LIFI4KU is a mercury source with strong spectral emission lines down to 320 nm for UV curing, fluorescence imaging, and UV printing.

  13. Working process LIFI offers an integrated light source that is straightforward to integrate into a projector. In this example LIFI consists of 5 primary sub-assemblies: • Printed circuit board (PCB) • RF power amplifier (PA) • Bulb • Optics • Enclosure

  14. Network Layer: RoutingAlgorithms •routingalgorithm=logicarouterusestodecide,foreachincomingPacket,which outputlinkthePacketshouldbetransmittedon •datagrampacket-switching:thisdecisionmustbemadeforeveryPacket •virtualcircuitpacket-switching:routingdecisionsmadeonlyatv.c.set-up •desirablepropertiesofaroutingalgorithm: •correctness,simplicity,efficiency–obviously •robustness–sinceusuallytheentirenetworkcan’tbe“re-booted”!!! •stability–routingalgorithmreachesequilibriuminareasonabletime •fairness,optimality –ofteninconflict,e.g. linkcapacities fullyutilisedby A-A’,B-B’,C-C’ trafficrespectively •optimality–withrespecttowhat?Whatarewetryingtooptimise?! •averagePacketdelay?totalPacketthroughput? •butthesegoalsarealsoinconflict:operatinganynetworknearcapacity implieslongqueueingdelaysinnodebuffers •compromise–minimisenumberofrelays(orhops)aPacketneeds 1 Network Layer: RoutingAlgorithms (cont.) •least-costrouting: •avalueisassignedtoeachlinkinthenetwork:thisisthecostofusingthislink •thecostofarouteisthecombinationofthevaluesofitslinks •thebestrouteistheonewiththelowestcost⇒knowhowtorelayincomingPackets •1foreachlink–findsroutewiththefewesthops •packetdelayonthelink–findsminimum-delayroute •…orsomecombinationofthese,orotherfactors! •routingalgorithmscanbedividedinto2classes: measurements(orestimates)ofthecurrentnetworktopologyandtrafficload •adaptive–routingdecisionsmaybechangedwhennetworktopologyand/or trafficloadchanges •maygetinformationjustfromneighbouringrouters,orfromallrouters trafficloadchangesmorethanathresholdpercentage,or… 2 •costassignedtoalinkcouldbe: •(financial)costofusingthelink–findscheapestroute •packettransmissiontimeonthelink–findsmaximum-bandwidthroute • optimality •nonadaptive,orstatic–routingdecisionsarepre-determinedandnotbasedon f ll ilidb •extremecase:selectanewrouteforeachPacket •mayre-determineroutesperiodically,orwhentopologychanges,orwhen Network Layer: RoutingAlgorithms (cont.) •oncethe“cost”ofeachlinkisknown,therouterscanrunaroutingalgorithmto determinethebestroutesforeachpossiblesender-receivertransmission •inpractice:routingalgorithmshouldbeadaptiveandde-centralised •the2mostcommonroutingalgorithmsaredistance-vectorandlink-state •distance-vector:eachrouterexchangesinformationabouttheentirenetwork withneighbouringroutersatregularintervals •neighbouringrouters=connectedbyadirectlink(e.g.aLAN) •regularintervals:e.g.every30seconds •link-state:eachrouterexchangesinformationaboutitsneighbourhoodwith all routersinthenetworkwhenthereisachange •neighbourhoodofarouter=setofneighbourroutersforthisrouter •eachrouter’sneighbourhoodinformationisfloodedthroughthenetwork •change:e.g.if aneighbouringrouterdoesnotreplytoastatusmessage •link-stateconvergesfasterinpractice,somorewidelyused •converges=determinesoptimalroutes,givenaparticularnetworktopology 3 Network Layer: Distance-Vector routing •cost=1foreverylink⇒findsminimum-hoproutes •“clouds”representLANs;numberincloudrepresentsnetworkID 4 inpractice:ro tingalgorithmsho ldbe and t lid h if i hb i t d t l t tt •A,B,C,D,E,Farerouters(orgateways)

  15. Network Layer: Distance-Vector routing (cont.) •eachroutersendsitsinformationabouttheentirenetworkonlytoitsneighbours: •howdonon-neighbouringrouterslearnabouteachotherandshareinformation? •aroutersendsitsinformationtoitsneighbours;eachneighbourrouteradds thisinformationtoitsown,andsendstheupdatedinformationtoits neighbours;sofirstrouterlearnsaboutitsneighbours’neighbours,... 5 Network Layer: Distance-Vector routing (cont.) •eachrouterstoresinformationaboutthenetworkinitsroutingtable NetworkID=finaldestinationofPacket Cost=numberofhopsfromthisrouterto finaldestination NextHop=neighbouringroutertowhich Packetshouldbesent •initially,allarouter knowsisthenetwork IDsofthenetworks towhichit isdirectly connected initialrouting tableexchanges routesyet) 6 Cost=numberofhopsfromthisrouterto knowsisthenetwork (nomulti-hop Network Layer: Distance-Vector routing (cont.) •howisarouter’sroutingtableupdatedwhennewinformationisreceived? keeptheentry withlowestcost becauseBis 1hopfromA •routingtableupdatealgorithm(distributedBellman-Fordalgorithm): •add1tocostofeachincomingroute(sinceeachneighbouris1hopaway) •ifanewdestinationlearned,additsinformationtotheroutingtable •ifnewinformationreceivedonanexistingdestination: •ifNextHopfieldisthesame,replaceexistingentrywiththenew informationevenifthecostisgreater(“newinformationinvalidatesold”) •ifNextHopfieldisnotthesame,onlyreplaceexistingentrywiththe newinformationifthecostislower 7 Network Layer: Distance-Vector routing (cont.) •exampleofroutingtableupdatealgorithm(unrelatedtoearlierExamplenetwork): Note:nonewinformationaboutNet1received, 8 soitsentryintheroutingtableis Note:nonewinformationaboutNet1received if i f i i d i i d i i notupdated

  16. Network Layer: Distance-Vector routing (cont.) •final(converged)routingtablesforearlierExamplenetwork: Note:choicebetween equal-costroutes dependsonexact sequenceofupdates 9 Network Layer: Distance-Vector routing inpractice •originalARPANET(forerunneroftheInternet)useddistance-vectorrouting •subsequentlyusedintheInternetasRIP(RoutingInformationProtocol) •avariationofdistance-vectorroutingisusedinBGP(BorderGateway Protocol),whichfindsroutesfromoneautonomoussystem(AS)toanotherAS •AS=apartoftheInternet(e.g.anetwork)managedbyoneentity •linkcostcanbesomethingotherthan1foreachlink… •e.g.packetdelay,numberofpacketsqueued,… •problemwithdistance-vectorrouting:count-to-infinityproblem •thisreferstotheslowconvergenceofdistance-vectorroutingalgorithms undersomeconditions •basicflaw–slowreactiontolink/routerfailurebecauseinformationonly comesfromneighbouringroutersandit maybeout-of-date(e.g.itmaynot properlyreflecttheimpactofthefailureon routecosts) •manyad-hocsolutionshavebeentried(e.g.“splithorizon”),buteitherthey alsofailtosolvethecount-to-infinityproblem,ortheyarehardtoimplement •thisslowconvergencewasoneofthemainreasonswhyothertypesof routingalgorithmwereexplored,leadingtolink-staterouting 10 bl ithdit t i fi it bl Network Layer: Link-State routing •eachroutersendsinformationaboutitsneighbourhoodtoeveryotherrouter: 11 Network Layer: Link-State routing (cont.) •linkcostisusuallyaweightedsumofvariousfactors •e.g.trafficlevel,securitylevel,packetdelay,… •linkcostisfromaroutertothenetworkconnectingittoanotherrouter • whenapacketisinaLAN(whichistypicallyabroadcastnetwork),every node–includingtherouter–canreceiveit⇒nocostassignedwhengoing fromanetworktoarouter Note:costsshown areexamplesonly 12 • from to

  17. Network Layer: Link-State routing (cont.) •routersshareinformationbyadvertising,whichmeanssendinglink-statepackets: Advertiser:IDofsendingrouter Network:IDofdestinationnetwork Cost:linkcosttoneighbour Neighbour:IDofneighbourrouter •aroutergetsitsinformationaboutitsneighbourhoodbysendingshortECHO packetstoitsneighboursandmonitoringtheresponses: theFigureshows howrouterA’s link-statepacket isfloodedtoall otherrouters 13 Network Layer: Link-State routing (cont.) •everyrouterbuildsalink-statepacketandfloodsitthroughthenetwork,sowhen allsuchpacketshavebeenreceivedatarouter,it canbuilditslink-statedatabase: Assumingthateveryrouter receivesthesamesetof routersweresynchronised), everyrouterbuildsthesame link-statedatabase. Usingthisdatabase,each routercanthencalculate itsroutingtable. 14 link-statepackets(asifthe Uihi d b h Network Layer: Link-State routing (cont.) •tocalculateitsroutingtable,arouterusesDijkstra’sShortest-Pathalgorithm •first,identifyalllinkcostsinthenetwork:eitherfromthelink-statedatabase, orusingthefactthatthecostofanylinkfromanetworktoarouteris0 15 NetworkLayer:Link-Staterouting – Dijkstra’salgorithm •thisalgorithmbuildsa shortest-pathspanningtreefortherouter:suchatreehasa routetoallpossibledestinations,andnoloops •therouterrunningthealgorithmistherootofits shortest-pathspanningtree •evenif allrouters’link-statedatabasesareidentical,thetreesdeterminedby theroutersaredifferent(sincetherootofeachtreeisdifferent) •anodeiseitheranetworkorarouter;nodesareconnectedbyarcs •thealgorithmkeepstrackof2setsofnodesandarcs–TemporaryandPermanent •initially,theTemporarysetcontainsallneighbournodesoftherouteritself, and thearcsconnectingthemtotherouter;onlytherouterisinitiallyPermanent •whenallnodesandarcsareinthePermanentset,thealgorithmhasterminated identifytheTemporarynodewhosearchasthelowestcumulativecostfromtheroot: thisnodeandarcaremovedintothePermanentset; anynodeswhichareconnectedtothenewPermanentnodeandarenotalreadyinthe Temporaryset,alongwiththeconnectingarcs,aremadeTemporary.Also,ifanynode alreadyintheTemporarysethasalowercumulativecostfromtherootbyusingaroute passingthroughthenewPermanentnode,thenthisnewroutereplacestheexistingone; repeatuntilallnodesandarcsarePermanent. 16

  18. NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) •asanExample,let’sfollowthestepsofthealgorithmrunbyrouterA 1. 2. 3. Note:arcsare markedwiththeir cumulativecost fromtheroot(not individualcosts) 17 NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) 4. markedwiththeir fromtheroot(not individualcosts) 5. Note:equalcumulativecosts⇒ chooseonearbitrarilyinstep6 18 Note:arcsare markedwiththeir cumulativecost i diid l ) k d ith th i h bi il i6 NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) 6. Note:arcsare markedwiththeir cumulativecost fromtheroot(not individualcosts) 7. 19 NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) 8. markedwiththeir cumulativecost fromtheroot(not individualcosts) 9. 20 Note:arcsare markedwiththeir markedwiththeir i diid l ) i diid l )

  19. NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) 10. Note:arcsare markedwiththeir cumulativecost fromtheroot(not individualcosts) 11. if thenewarctonetwork66from routerDhadalowercumulativecost thantheonefromrouterC,then thenewlinkwouldreplacetheoldone 21 NetworkLayer:Link-Staterouting – Dijkstra’salgorithm (cont.) 12. markedwiththeir cumulativecost fromtheroot(not individualcosts) 13. all nodesandarcsare Permanent⇒STOP: thisrouter’sshortest-path spanningtreehasbeenfound 22 Note:arcsare markedwiththeir markedwiththeir i diid l ) i diid l ) th th f t C th Network Layer: Link-State routing – routing table •oncearouterhasfounditsshortest-pathspanningtree,it canbuilditsroutingtable •tocompletetheExample,hereisrouterA’slink-stateroutingtable: Note:eachrouter’sroutingtable will(ingeneral)bedifferent Networks14,23,and78don’thave a“Nextrouter”entrybecausethey aredirectlyconnectedtothisrouter •inlargenetworks,thememoryrequiredtostorethelink-statedatabaseandthe computationtimetocalculatethelink-stateroutingtablecanbesignificant •inpractice,sincethelink-statepacketreceptionsarenotsynchronised,routersmay beusingdifferentlink-statedatabasestobuildtheirroutingtables:howinaccurate the resultsaredependsonhowdifferenttherouters’“views”ofthenetworkare 23 Network Layer: Link-State routing in practice •link-stateroutingalgorithmshaveseveraldesirableproperties,e.g.rapidconvergence;small amountoftrafficgenerated;rapidresponsetotopologychanges •examplesfromtheInternetaretheOpenShortestPathFirst(OSPF)andIntermediate SystemtoIntermediateSystem(IS-IS)routingprotocols •linkcostscanbeconfiguredinOSPF.Possiblelinkcostsinclude: ¾reliability:assignedbyadministrator,indicateshowoftenthelinkfails ¾linkbandwidth •OSPFrequiresalotofmemory:eachrouterholdsitsroutingtable&link-statedatabase •Dijkstra’salgorithmcomputationsareprocessor-intensive place–whichcouldbeeverytimealink-statepacketisreceived •OSPFcanconsumealotofbandwidthifthenetworktopologychangesoften •link-statepacketssenttoallroutersusingreliableflooding ¾needsequencenumberandtime-to-live(TTL)fieldineachpacket… ¾1foreachlink ¾packetdelay 1f hlik ¾financialcostofthelink ¾legacyroutersmaybeunabletorelaypacketswhenthesecalculationsaretaking 24

  20. Different Between The Technologies

  21. POTENTIAL APPLICATION OF LI-FI • Traffic lights can communicate to the car and with each other.

  22. POTENTIAL APPLICATION OF LI-FI • INTRINSICALLY SAFE ENVIRONMENTS • Visible Light is more safe than RF, hence it can be used in places where RF can't be used such as petrochemical plants , airplanes etc.

  23. PUBLIC INTERNET HOTSPOTS • There are millions of street lamps deployed around the world. • Each of these street lamps could be a free access point.

  24. POTENTIAL APPLICATION OF LI-FI • ON OCEAN BEDS • Li-Fi can even wok underwater were Wi-Fi fails completely, thereby throwing open endless opportunities for military/navigation operations.

  25. Advantages • High Security • Easy To Use • Fast Data Transfer • Reliable • Harmlessness • Low Cost

  26. Concussion • The possibilities are numerous and can be explored further. If his technology can be put into practical use, every bulb can be used something like a Wi-Fi hotspot to transmit wireless data and we will proceed toward the cleaner, greener, safer and brighter future.

  27. REFRENCES • Google • Wikipedia • Lificonsortium.org • Purevlc.com • ebookbrowse.com/an002-instrumentlighting-pdf-d20428293

  28. THANK YOU ANY QUERIES……..

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