Harald-Haas-每一個燈泡都傳輸無線信號

HeraldHaas

Wirelessdatafromeverylightbulb

Doyouknowthatwehave1.4millioncellularradiomastsdeployedworldwide?Andthesearebasestations.Andwealsohavemorethan5billonsofthesedeviceshere.Thesearecellularmobilephones.Andwiththesemobilephones,wetransmitmorethan600terabytesofdataeverymonth.Thisisa6with14zeroes—averylargenumber.Andwirelesscommunicationshasbecomeautilitylikeelectricityandwater.Weuseiteveryday.Weuseitinoureverydaylivesnow—inourprivatelives.Weeverhavetobeaskedsometimes,verykindly,toswitchoffthemobilephoneateventslikethisforgoodreason.

Andit’sthisimportancewhyIdecidedtolookintotheissuesthatthistechnologyhas,becauseit’ssofundamentaltoourlives.Oneoftheissuesiscapacity.Thewaywetransmitwirelessdataisbyusingelectromagneticwaves—inparticular,radiowaves.Radiowavesarelimited.Theyarescarce;theyareexpensive;andweonlyhaveacertainrangofit.Thereisanotherproblem.Thatisefficiency.These1.4millioncellularradiomasts,orbasestations,consumealotofenergy.Andmindyou,mostoftheenergyisnotusedtotransmittheradiowaves;itisusedtocoolthebasestations.Thentheefficiencyofsuchabasestationisonlyataboutfivepercent.Andthatcreatesabigproblem.Thenthere’sanotherissuethatyou’reallawareof.Youhavetoswitchoffyourmobilephoneduringflights.Inhospitals,theyaresecurityissues.Theseradiowavespenetratethroughwalls.Theycanbeintercepted,andsomebodycanmakeuseofyournetworkifhehasbadintentions.Sothesearethemainfourissues.

Butontheotherhand,wehave14billionofthese:lightbulbs.Andlightispartoftheelectromagneticspectrum.Solet’slookatthisinthecontextoftheentireelectromagneticspectrum,wherewehavegammarays.Youdon’twanttogetclosetogammarays,itcouldbedangerous.X-raysisusefulwhenyougotohospitals.Thenthere’sultravioletlight.Infrared—duetoeyesafetyregulations,canbeonlyusedwithlowpower.Andthenwehavetheradiowaves,theyhavetheissuesI’vejustmentioned.Inthemiddlethere,wehavethisvisiblelightspectrum.Wouldn’titbegreattousethatforwirelesscommunications?Notonlythat,Icomparedittotheentirespectrum.Guesswhat?Wehave10000timesmoreofthatspectrum,whichisthereforustouse.Sonotonlydowehavethishugeamountofspectrum,let’scomparethatwithanumberI’vejustmentioned.Wehave1.4millionexpensivelydeployed,inefficientradiocellularbasestations.Multiplythatby10000,andthenyouendupat14billion.14billionisthenumberoflightbulbsinstalledalready.Sowehavetheinfrastructurethere.

Canweusethemforcommunication?Yes!Whatdoweneedtodo?Theonethingweneedtodoiswehavereplacetheseinefficientincandescentbulbs,florescentlight,withthisnewtechnologyofLED.LEDisasemiconductor.It’sanelectronicdevice.Ithasaveryniceacuteproperty.Itsintensitycanbemodulatedatveryhighspeeds,anditcanbeswitchedoffatveryhighspeeds.Thisisafundamentalbasicpropertythatweexploitwithourtechnology.

Solet’sshowhowwedothat.Whatwehavehereisanordinarydesklamp.WefitaLEDlightbulb,worththreeU.S.dollars,putinoursignalprocessingtechnology.Andthenwhatwehavehereisalittlehole.Andthelightgoesthroughthathole.There’sareceiver.Thereceiverwillconverttheselittle,subtlechangesintheamplitudethatwecreatethereintoanelectricalsignal.Andthatsignalisthenconvertedbacktoahigh-speeddatastream.Inthefuturewehopethatwecanintegratethislittleholeintosmartphones.SowhathappenswhenIswitchonthatlight?Asyouwouldexpect,it’salight,adesklamp.Putyourbookbeneathitandyoucanread.It’silluminatingthespace.Butatthesametime,youseethisvideocominguphere.Andthat’savideo,ahigh-definitionvideothatistransmittedthroughthatlightbeam.It’sthelightthattransmitsthisvideoinasplitstream.Andifyoulookatthelight,itisilluminatingasyouwouldexpect.Youdon’tnoticewithyourhumaneye.Youdon’tnoticethesubtlechangesintheamplitudethatweimpressontothislightbulb.It’sservingthepurposeofillumination,butatthesametime,weareabletotransmitthisvideo.Yousee,evenlightfromthecellingcomesdownheretothereceiver.Itcanignorethatconstantlight,becauseallthereceiver’sinterestedinaresubtlechanges.

I’vementionedtoyouthefourchallenges.Capacity:Wehave10000timesmoreLEDsinstalledalreadyintheinfrastructurethere.Youwouldagreewithme,hopefully,there’snoissueofcapacityanymore.Efficiency:Thedatatransmissioncomesforfree—highlyenergyefficient.AndthenI’vementionedtheavailability.Youwillagreewithmethatwehavelightsinthehospitals.Wehavelightinanaircraft.Soit’severywhereinadaythereislight.Thesearepotentialsourcesforhighspeeddatatransmission.Security:youwouldagreewithmethatlightdoesn’tpenetratethroughwalls.IfIhavesecuredata,nooneontheothersideofthisroomthroughthatwallwouldbeabletoreadthatdata.

Soforme,theapplicationofit,tome,arebeyondimaginationatthemoment.Wehavehadacenturyofverynice,smartapplicationdevelopers.Andyouonlyhavetonotice,wherewehavelight,thereisapotentialwaytotransmitdata.Icangiveyouafewexamples:Thisisaremoteoperatedvehiclebeneaththeocean.Andtheyuselighttoilluminatespacedownthere.Thislightcanbeusedtotransmitwirelessdatathatthesethingsusetocommunicatewitheachother.Inhospitals,fornewmedicalinstruments.Instreetsfortrafficcontrol.CarshaveLED-basedheadlights,LED-basedbacklight,andcarscancommunicatewitheachotherandpreventaccidentsinthewaythattheyexchangeinformation.Traf