7/27/2019 LaranRFID
1/30
White Paper
A BASIC INTRODUCTION TO RFID TECHNOLOGY AND ITS
USE IN THE SUPPLY CHAIN
January 2004
7/27/2019 LaranRFID
2/30
2
Confident
TABLE OF CONTENTS
EXECUTIVE SUMMARY .................................................................................................3
INTRODUCTION TO RFID ............................................................................................4
HOW RFID WORKS ......................................................................................................5
RFID systems..............................................................................................................5Communication............................................................................................................ 5
Anti-collision .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... .... .... .... . 5
RFID BUILDING BLOCKS.............................................................................................6
RFID Tags............................................................................................................................................................... 6Packaging ................................................................................................................... 6Examples of different formats............ ........ ......... ........ ......... ......... ........ ......... ........ ....... 6Tag Cost .....................................................................................................................6
Tag ICs ......................................................................................................................8Tag Classes ................................................................................................................ 8Selecting a tag............................................................................................................. 9
Active and passive tags .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... .... ... .... .... ... 10How tags communicate .............................................................................................. 11Tag Orientation (polarization)...................................................................................... 13Tag standards............................................................................................................ 14
RFID Readers.......................................................................................................................................................17Handheld Readers ..................................................................................................... 18
RFID Label Printers............................................................................................................................................18
Reader Antennas ................................................................................................................................................19
RFID TECHNOLOGY IN THE SUPPLY CHAIN............................................................ 20
Definition of the Supply Chain. .................................................................................... 20How will RFID help improve supply chain efficiency........ ........ ......... ........ ......... ......... ... 20The main benefits of RFID in the supply chain. ........ ......... ........ ......... ........ ......... ........ . 20
THE EPC ELECTRONIC PRODUCT CODE................................................................ 22
EPC Origins ..........................................................................................................................................................22
EPC layout ............................................................................................................................................................22
EPC infrastructure..............................................................................................................................................23Middleware or Savant Software.................................................................................. 24Object Name Service (ONS)....................................................................................... 24Physical Markup Language (PML)............................................................................... 24How the EPC will automate the supply chain ............................................................... 25
SECURITY IN RFID SYSTEMS................................................................................... 26
CONCLUSION ............................................................................................................ 27
ABOUT THE AUTHOR................................................................................................. 27
APPENDIX A .......................................................................................................... 28
More about Near and Far fields ........ ......... ........ ......... ......... ........ ......... ........ ......... ...... 28
APPENDIX B ........................................................................................................ 30
EIRP and ERP Power Emissions ................................................................................ 30
7/27/2019 LaranRFID
3/30
3
Confident
Executive Summary
In2003RFIDseemedtohaveappearedfromnowhere,andintothespotlightasoneofthehottest technologies around. Everyone from journalists, analysts, VCs, technologycompanies and retail giants like Wal-Mart were making public statements, mandates,predicationsandinvestments,basedonthepromisethatRFIDwassettorevolutionizetheglobalsupplychainonascalenotseensincetheinternetrevolutioninthe1990s.Equallysurprising isthatRFIDisnot new,itsbeenaround forwellover10 years, and isalreadyinuseinapplicationslikeaccesscontrolandtransport.Whilsttherehavebeenmanyfalsestartsandpromisesinthepast,whathasmadethedifferencethistimearound,isthecreation of the EPC (electronic product code) coupled with lower tag costs, and themandated adoption of RFID by Wal-Mart and Tesco for all their suppliers by 2005-6.
Furthermore,theEuropeanParliamenthasannouncedlegislationwhichobligesallgoodstobe traceable throughout the supply chain by2005. These initiatives, andothers like therecentUS-DODannouncementsarenowdrivingthemarketandincitingmanycompaniesto
developstrategiesforRFIDcompliance.TheuseofRFIDcombinedwiththeEPCpromisestoprovidedataaboutproductsneveravailablebefore.ManyitemsproducedwilleventuallyhavetheirownuniqueIDnumbers.Allparts of thesupply chain includingmanufactures,distributors and retailerswill beabletohave instant access to information about an individual product. RFID is not expected toreplacebarcodessimplybecausetagsarestilltooexpensiveeventhoughtheirpriceshavefallen to around 20 cents in volume versus0.2 cents for a bar code label. Adoption is
thereforelikelytohappenfirstatthePaletteandCratelevel,thenastechnologyadvancesandcostsreducefurther,wecanexpecttoseetagsonmoreandmorehighvalueitems.ThewideadoptionofRFIDacrossthesupplychainwillbringsignificantbenefitsleadingtoreducedoperationalcostsandhenceincreasedprofits.Manyanalystssuggestthatthiswill
happeninthreeprimaryareas.
Reducedinventoryandshrinkage Benefitfromareductioninstoreandwarehouselaborexpenses Areductioninout-of-stockitems
Withsomuchhighprofilebacking,momentumandindisputablebenefits,canRFIDfail?Mostanalyststhinknot,butareawareofthemanyobstacles,misconceptionsandissuestoberesolvedonthewayincluding;
Tagpricesandefficiencies HarmonizationofRFIDstandards, Interoperabilitythroughoutthesupplychain
ITinfrastructuretohandlelargevolumesofdata Changeofworkandlaborpractices Sharedcostofdeployment Privacyissues
ThispaperisaimedatbothtechnicalandbusinessprofessionalswhowanttounderstandhowRFIDbasicallyworks,thevariousbuildingblocksandthepotentialthetechnologyhasforthesupplychain.FinallyIhopethatitwillalsoshedlightonsomeofthemysteriesandconfusionsurroundingRFIDandallthatitpromises.
7/27/2019 LaranRFID
4/30
4
Confident
Introduction to RFID
Ingeneralterms,RFID(RadioFrequencyIdentification)isameansofidentifyingapersonorobjectusingaradiofrequencytransmission.Thetechnologycanbeusedtoidentify,track,sort or detect a wide variety of objects.Communication takes placebetween a reader(interrogator)andatransponder (SiliconChipconnectedtoanantenna)oftencalledatag.Tagscaneitherbeactive(poweredbybattery)orpassive(poweredbythereaderfield),andcomeinvariousformsincludingSmartcards,Tags,Labels,watchesandevenembeddedin
mobile phones. The communication frequencies useddepends to a large extent on theapplication, and range from 125KHz to 2.45 GHz. Regulations are imposed by mostcountries(groupedinto3Regions)tocontrolemissionsandpreventinterferencewithotherIndustrial,ScientificandMedicalequipment(ISM).
Table 1. Most commonly used RFID frequencies for passive tags Performance overview
LF HF UHF MicrowaveFrequencyRange
7/27/2019 LaranRFID
5/30
5
Confident
How RFID works
Figure 1. Typical RFID system
RFID systemsInatypicalsystemtagsareattachedtoobjects.Eachtaghasacertainamountofinternalmemory (EEPROM) inwhich itstoresinformation abouttheobject, suchasits unique ID
(serial) number, or in some casesmore details includingmanufacture date andproductcomposition.Whenthesetagspassthroughafieldgeneratedbyareader,theytransmitthisinformationbacktothereader,thereby identifyingtheobject.UntilrecentlythefocusofRFIDtechnology was mainly on tags and readers whichwere being used in systems whererelativelylowvolumesof dataare involved.ThisisnowchangingasRFID inthesupplychainisexpectedtogeneratehugevolumesofdata,whichwillhavetobefilteredandrouted
to thebackend ITsystems.To solve this problem companies have developed specialsoftwarepackagescalledsavants,whichactasbuffersbetweentheRFIDfrontendantheITbackend.SavantsaretheequivalenttomiddlewareintheITindustry.
CommunicationThecommunicationprocessbetweenthereaderandtagismanagedandcontrolledbyoneof several protocols, such as the ISO15693 and ISO18000-3 forHForthe ISO18000-6,andEPCforUHF.Basicallywhathappensisthatwhenthereaderisswitchedon,itstartsemittingasignalattheselectedfrequencyband(typically860-915MHzforUHFor13.56MHzforHF).
Anycorrespondingtag inthevicinityofthereaderwilldetectthesignalanduse theenergyfrom it towake up andsupply operatingpower toits internal circuits.Once theTaghasdecodedthesignalasvalid,itrepliestothereader,andindicatesitspresencebymodulating(affecting)thereaderfield.
Anti-collisionIfmanytagsarepresentthentheywillall replyatthesame time,whichatthereaderendisseen asa signal collision and an indication ofmultiple tags.The reader manages this
problem by using an anti-collision algorithm designed to allow tags to be sorted andindividuallyselected.Thereare manydifferenttypesofalgorithms(BinaryTree,Aloha....)which are defined as part of the protocol standards. The number of tags that can beidentifieddependson thefrequencyandprotocolused,andcantypically rangefrom50tags/sforHFandupto200tags/sforUHF.Onceatagisselected,thereaderisabletoperformanumberofoperationssuchasreadthetagsidentifiernumber,orinthecaseofaread/writetagwriteinformationtoit.Afterfinishingdialogingwiththetag,thereadercantheneitherremoveitfromthelist,orputitonstandby
untilalatertime.Thisprocesscontinuesundercontroloftheanticollisionalgorithmuntilalltagshavebeenselected.
7/27/2019 LaranRFID
6/30
6
Confident
RFID Building Blocks
RFID Tags.PackagingEveryobject tobe identifiedinanRFIDsystemwillneedtohaveatagattachedtoit.Tagsaremanufacturedinawidevarietyofpackagingformatsdesignedfordifferentapplicationsand environments. Thebasicassemblyprocess (seeFig4.) consistsof first a substratematerial (Paper,PVC,PET...),uponwhichanantennamade from oneofmany differentconductivematerialsincludingSilverink,Aluminumandcopperisdeposited.NexttheTagchipitself is connectedto theantenna,usingtechniquessuchaswirebondingorflip chip(seeFig4.).FinallyaprotectiveoverlaymadefrommaterialssuchasPVClamination,EpoxyResinorAdhesivePaper,isoptional lyaddedtoallowthetagtosupportsomeofthephysicalconditionsfoundinmanyapplicationslikeabrasion,impactandcorrosion.
Fig 2. Basic Tag Assembly
Examples of different formats
Creditcardsizeflexiblelabelswithadhesivebacks Tokensandcoins Embeddedtagsinjectionmoldedintoplasticproductssuchascases Wristbandtags
Hardtagswithepoxycase Keyfobs
TagsdesignedspeciallyforPalettesandcases Papertags
Tag CostThetypeofmaterialsandassemblymethodsusedtopackagetagsimpactdirectlyonthefinal cost ( around 30%), and tosome extent on the communication performance.Inthesupplychain,thecostoftagsisoneofthemainconsiderationsformassadoption,withthe5centtagbeingthemuchtalkedabouttarget.Howtoachievethisfigureiscurrentlyoneofthegreatdebates.Traditionallychipdiesizehasalwaysbeenthekeyfocus,andICcompanies
havemanagedtogetdiesizes(chiparea)downtoaround0.3mm2forUHFchips,resultinginamanufacturingcostofabout1-2centsdependingontheSiliconprocess.Thisleaves3centsfortherest!whichiswheretherealchallengenowseemstolie.Therearesolutionsin
PVC
PET
PAPER .
Substrate Antenna
Copper
ALU
Conductive Ink .
Chip
Flip chipconnection
Antenna
Wire
Gold
bumpsChipSurface
Overlay
PVC
Epoxy Resin
AdhesivePaper
.
7/27/2019 LaranRFID
7/30
7
Confident
thepipelinefromcompanieslikeAlienTechnologyandPhilipsSemiconductors,whomhavebothdevelopednewchipassemblytechniqueswhichwhenusedwiththeverylargevolumes(billions of tags) expected in the supply chainpromises to optimize costs to the levelsrequiredinordertoreachthe5centgoal.
Fig 3. HF (13.56 MHz) Tag examples
Paperlabelswithconductivesilverinkantennas Flexiblelabelwithanaluminumantenna
-
Courtesy of ASK
Courtesy of Inside Contactless
Fig 4. UHF (860 930 MHz) tag examples
Courtesy of MATRICS
Courtesy of IPICO
Coil on chip Tags (image courtesy of Maxell)
A new and fascinating development for tags is based on havingtheantennadepositeddirectlyontothetagchipssurface.Althoughthecommunicationdistanceislimitedtoaround
3mm,theresultisamicroscopictagwhichcanbeconcealedforexampleinbanknotes,as
proposedrecentlybyHitachi-Maxell.BothMaxellandInsidecontactlesshavedevelopedworkingversionsofthesetagsatUHF,HF(Maxell)andHF(Inside).
7/27/2019 LaranRFID
8/30
8
Confident
Tag ICs
Fig 5. Basic Tag IC architecture
RFID tag ICs are designed and manufactured using some of the most advancedandsmallestgeometrysiliconprocessesavailable.Theresultisimpressive,whenyouconsiderthatthesizeofaUHFtagchipisaround0.3mm2i.e.aboutthesizeofthesquarebelow
Intermsofcomputationalpower,RFIDtagsarequitedumb,containingonlybasiclogicandstatemachinescapableofdecodingsimpleinstructions.Thisdoesnotmeanthattheyaresimple to design! In fact very real challenges exist such as, achieving very low powerconsumption,managing noisy RF signals and keepingwithin strictemissionregulations.Other important circuitsallow thechip to transferpower from the reader signal field, andconvertitviaarectifierintoasupplyvoltage.Thechipclockisalsonormallyextractedfrom
thereadersignal.MostRFIDtagscontainacertainamountofNVM(NonvolatileMemory)likeEEPROMinordertostoredata.Theamountofdatastoreddependsonthechipspecification,andcanrangefromjustsimpleIdentifier numbers of around 96bits tomore information about theproductwith upto32Kbits.However,greaterdatacapacityandstorage(memorysize)leadstolargerchipsizes,andhencemoreexpensivetags.In1999TheAUTO-IDcenter(nowEPCGlobal)basedattheMIT(MassachusettsInstituteofTechnology)intheUS,togetherwithanumberofleadingcompanies, developed the idea of an unique electronic identifier code called the EPC(ElectronicProductCode).TheEPCissimilarinconcepttotheUPC(UniversalProductCode)usedin barcodestoday.Havingjusta simplecodeofupto256bitswouldleadto
smallerchipsize,andhencelowertagcosts,whichisrecognizedasthekeyfactorforwidespreadadoptionofRFIDinthesupplychain.TagsthatstorejustanIDnumberareoftencalledLicensePlateTags
Tag ClassesOneofthemainwaysofcategorizingRFIDtagsisbytheircapabilitytoreadandwritedata.
Thisleadstothefollowing4classes.EPCglobalhasalsodefinedfiveclasseswhicharesimilartotheonesbelow.
AC/DCConverter
Powercontrol
Decoder
EEPROMMemory
Modulator Encoder
Instructionsequencer
Tag antenna
Connections
Chip
7/27/2019 LaranRFID
9/30
9
Confident
CLASS0 READONLY.FactoryprogrammedThesearethesimplesttypeoftags,wherethedata,whichisusuallyasimpleIDnumber,(EPC) iswrittenonlyonce intothe tagduringmanufacture.Thememory is thendisabledfrom any further updates. Class 0 isalso used todefinea categoryof tagscalledEAS(electronicarticlesurveillance)oranti-theftdevices,whichhaveno ID,andonlyannouncetheirpresencewhenpassingthroughanantennafield.CLASS1 WRITEONCEREADONLY(WORM)FactoryorUserprogrammed
In this case the tagismanufacturedwithnodatawritten into thememory. Datacantheneitherbewrittenby thetagmanufacturerorby theuser onetime.Followingthisnofurtherwritesareallowedandthetagcanonlyberead.TagsofthistypeusuallyactassimpleIdentifiersCLASS2READWRITEThisisthemostflexibletypeoftag,whereusershaveaccesstoreadandwritedataintothetagsmemory.Theyaretypicallyusedasdataloggers,andthereforecontainmorememoryspacethanwhatisneededforjustasimpleIDnumber.
CLASS3 READWRITEwithonboardsensorsThese tagscontainon-boardsensorsforrecordingparametersliketemperature,pressure,andmotion,whichcanbe recordedbywritinginto the tagsmemory.Assensor readingsmustbetakenintheabsenceofareader,thetagsareeithersemi-passiveoractive.CLASS4READWRITEwithintegratedtransmitters.Thesearelikeminiatureradiodeviceswhichcancommunicatewithothertagsanddeviceswithoutthepresenceofareader.Thismeansthattheyarecompletelyactivewiththeirown
batterypowersource.
Table 2. Different tag classes
Class Knownas Memory PowerSource Appl ica t ion0 EAS EPC[1] None EPC Passive Ant-theft ID
1 EPC Read-Only Any Identification
2 EPC Read-Write Any Datalogging
3 SensorTags Read-Write Semi-Passive/Active Sensors4 SmartDust Read-Write Active AdHocnetworking
[1]ThesectiononEPCstandardsevolutionshowsthattheEPCclass0islikelytoevolvetoaread-write
Selecting a tagChoosingtherighttagforaparticularRFIDapplicationisanimportantconsideration,andshouldtakeintoaccountmanyofthefactorslistedbelow:
Sizeandformfactorwheredoesthetaghavetofit?
Howclosewilltagsbetoeachother Durabilitywillthetagneedtohaveastrongouterprotectionagainstregularwearandtear. Isthetagre-usable Resistancetoharshenvironments(corrosive,steam...) Polarizationwhatwillbethetagsorientationwithrespecttothereaderfield Exposuretodifferenttemperatureranges Communicationdistance Influenceofmaterialssuchasmetalandliquids Environment(Electricalnoise,otherradiodevicesandequipment) OperatingFrequency(LF,HForUHF) SupportedCommunicationStandardsandprotocols(ISO,EPC)
7/27/2019 LaranRFID
10/30
10
Confident
RegionalRegulations(US,EuropeandAsia) WillthetagdataneedtostoremorethanjustanIDnumberlikeanEPC Anti-collision-howmanytagsinthefieldatthesametimeandhowquicklymusttheybe
detected.
Howfastwilltagsmovethroughthereaderfield Readersupportwhichreaderproductsareabletoreadthetag Doesthetagneedtohavesecurity Dataprotectionbyencryption
Fig 6. How passive tags are defined
Active and passive tagsFig6,showsthatthefirstbasicchoicewhenconsideringatagisbetweeneitherpassive,semi-passiveoractive. Passivetagscanbereadatadistanceofupto4-5musingtheUHFfrequencyband,whilsttheothertypesoftags(semi-passiveandactive)canachievemuch
greaterdistancesofupto100mforsemi-passive,andseveralkilometersforActive.Thislargedifferenceincommunicationperformancecanbeexplainedbythefollowing; Passive tags use the reader field as a source of energy for the chip and for
communicationfromand tothe reader.Theavailablepower fromthereaderfield,notonly reduces very rapidly with distance ,but is also controlled by strict regulations,resultingina limitedcommunicationdistanceof 4 -5mwhenusingtheUHFfrequency
band(860Mhz930Mhz). Semi-Passive(batteryassistedbackscatter)tagshavebuiltinbatteriesandthereforedo
notrequireenergyfromthereaderfieldtopowerthechip.Thisallowsthemtofunctionwithmuchlowersignalpowerlevels,resultingingreaterdistancesofupto100meters.Distance is limited mainly due to the fact that tag does not have an integratedtransmitter,andisstillobligedtousethereaderfieldtocommunicatebacktothereader.
Activetagsarebatterypowereddevicesthathaveanactivetransmitteronboard.Unlike
passivetags,activetagsgenerateRFenergyandapplyittotheantenna.Thisautonomyfrom the reader means that they can communicate at distances of over several
kilometers.Thispaperfocusesonpassivetags.Theexperiencegainedbydifferentcompaniesrunningvarioustrailsandevaluationshassofarshown,thatoutofthedifferentRFIDfrequenciesLF,HF,UHFandmicrowave(seefig1).HFandUHFarethebestsuitedtothesupplychain.Furthermore, it is expected that UHF due to its superior read range, will become thedominantfrequency.ThisdoesnotmeanhoweverthatLFandmicrowavewillnotbeusedincertaincases.
Passive
LF, HF
UHFMicrowave
Power source Frequency
Class 0
Class 1
Class 2
18000
Protocol
Paper label
PVC.
Package
256 bits
PropreitarySemi-passive
7/27/2019 LaranRFID
11/30
11
Confident
Table 3. Comparison of Passive and Active Tags
Advantages Disadvantages Remarks
Passive
Longerlifetime
Widerrangeofformfactors
Tags are more mechanicallyflexible
Lowestcost
Distancelimitedto4-5m(UHF)
Strictlycontrolledby
localregulations
Most widely used inRFIDapplications.
TagsareLF,HForUHF
Semi-Passive
Usedmainlyinrealtimesystems to track highvalue materials orequipmentthroughoutafactory.
TagsareUHF
Active
Greater communication
distance
Canbeusedtomanageotherdevices like sensors (Temp,
pressureetc) Do not fall under the same
strict power regulationsimposedonpassivedevices
Expensive - due tobattery, and tagpackaging
Reliability - impossible
todeterminewhetherabatteryisgoodorbad,
particularly inmultipletransponderenvironments.
Widespread
proliferation of activetransponderspresents
an environmentalhazardfrompotentiallytoxic chemicals inbatteries.
Used in logistics fortrackingof containersontrains,trucksetc..Tags are UHF or
microwave
How tags communicate
NearandFar f ie ldsInordertoreceiveenergyandcommunicatewithareader,passivetagsuseoneofthetwo
followingmethodsshowninfig7.Theseare nearfieldwhichemploysinductivecouplingofthetagtothemagneticfieldcirculatingaroundthereaderantenna(likeatransformer),andfarfieldwhichusessimilartechniquesto radar(backscatterreflection)bycouplingwiththeelectricfield.ThenearfieldisgenerallyusedbyRFIDsystemsoperatingintheLFandHFfrequencybands,andthefarfieldforlongerreadrangeUHFandmicrowaveRFIDsystems.Thetheoreticalboundarybetweenthetwofieldsdependsonthefrequencyused,andisin
factdirectlyproportionalto/2where =wavelength.Thisgivesforexamplearound3.5
metersforanHFsystemand5cmforUHF,bothofwhicharefurtherreducedwhenotherfactorsaretakenintoaccount.(seeTableA-1AppendixA)Note:AmoredetailedexplanationonnearandfarfieldscanbefoundinAppendixA.
Fig 7. Two different ways of Energy and information transfer between reader and tag
S
N
a
Reader
Magnetic Field (near field)Inductive cou lin
LF and HF
a
Reader
UHF
Electric Field (far field)Backscatter
7/27/2019 LaranRFID
12/30
12
Confident
LF, HF TagsTagsatthesefrequenciesuseinductivecouplingbetweentwocoils(readerantennaandtagantenna - seefig7)inordertosupplyenergyto thetagandsendinformation.Thecoilsthemselvesareactually tunedLC circuits,whichwhensettotherightfrequency(ex;13.56
MHz),willmaximize theenergytransferfrom readerto tag. Thehigherthe frequency theless turns required (13.56MHztypicallyuses3 to5 turns).Communicationfromreadertotag occurs by the readermodulating(changing)its fieldamplitudeinaccordancewiththedigital information to be transmitted (base band signal). The result is the well knowntechniquecalledAMorAmplitudeModulation.Thetagsreceivercircuitisabletodetectthemodulatedfield,anddecodetheoriginalinformationfromit.However,whilstthereaderhasthepowertotransmitandmodulateitsfield,apassivetagdoesnot.Howiscommunicationthereforeachievedbackfromtagtoreader?.Theanswerlies inthe inductivecoupling.Justasinatransformerwhenthesecondarycoil(tagantenna)changestheloadandtheresultisseeninthePrimary(readerantenna).The
tagchipaccomplishesthissameeffectbychangingitsantennaimpedanceviaaninternalcircuit,whichismodulatedatthesamefrequencyasthereadersignal.Infactitsalittlemorecomplicatedthanthisbecause,iftheinformationiscontainedinthesamefrequencyasthereader,thenitwillbeswampedbyit,andnoteasilydetectedduetotheweakcouplingbetweenthereader andtag.Tosolvethisproblem, therealinformationisofteninsteadmodulatedintheside-bandsofahighersub-carrierfrequencywhichismoreeasilydetectedbythereader.
Fig 8. Creation of two higher frequency side-bands
UHF tagsPassivetagsoperatingattheUHFandhigherfrequenciesusesimilarmodulationtechniques
(AM)aslowerfrequencytags,andalsoreceivetheirpowerfromthereaderfield.Whatisdifferent however, is the way that energy is transferred, andthe design ofthe antennasrequiredtocaptureit.Wehavealreadymentionedthatthisisachievedusingthe farfield,whichisin facttheregioninElectromagneticTheorywheretheelectricandmagneticfield
components of a conductor (antenna) breakaway, and propagate into free spaceas acombinedwave.Atthispoint,thereisnofurtherpossibilityofinductivecouplinglikeinHFsystems,becausethemagneticfieldisnolongerlinkedtotheantenna.Transmissionofthiswaveinthefarfieldisthebasisofallmodernradiocommunication.Insomesystemssuchastransmissionlines(coaxialcables),thepropagationofthesewavesisrestrictedasmuchaspossibleviaspecialshieldingastheyconstituteapowerloss.Forantennasitstheinverse,propagationisencouraged.Whenthepropagatingwavefromthereadercollideswithatagantennaintheformofadipole (seefig7),partoftheenergyisabsorbedtopowerthetagandasmallpartisreflectedbacktothereaderinatechniqueknownasback-scatter.Theory
showsthatfortheoptimalenergytransferthelengthofthedipolemustbeequalto/2,which
fc =13.56 MHz
fsub = 212 KHz
fc =13.772 MHzfc =13.348 MHz
Reader Carrier signal0 dB
-80 dB
Modulation Informationin subcarrier side bands
Si nal
7/27/2019 LaranRFID
13/30
13
Confident
givesa dimensionof around16cm.In reality the dipole ismade upof two /4lengths.Deviatingfromthesedimensionscanhaveaseriousimpactonperformance.Justasforlowerfrequencytagsusingnearfieldinductivecoupling,apassiveUHFtagdoes
nothavethepowertotransmitindependently.Communicationfromtagtoreaderisachievedbyalteringtheantennainputimpedanceintimewiththedatastreamtobetransmitted.Thisresultsinthepowerreflectedbacktothereaderbeingchangedintimewiththedatai.e.itis
modulated.Fromanapplicationspointofview,usingthetechniqueoffarfieldback-scattermodulationintroducesmanyproblemsthatarenotsoprevalentinHFandlowerfrequencysystems.Oneofthemostimportantoftheseisduetothefactthatthefieldemittedbythereaderisnotonlyreflectedbythetagantenna,butalsobyanyobjectswithdimensionsintheorderofthewavelengthused.Thesereflectedfields,ifsuperimposedonthemainreaderfieldcanleadtodampingandevencancellation.
Tag Orientation (polarization)
How tags are placed with respect to the polarization of the readers field can have asignificanteffectonthecommunicationdistanceforbothHFandUHFtags,resultinginareducedoperatingrangeofupto50%,andinthecaseofthetagbeingdisplacedby90(seefig 9), notbeing able to read the tag . The optimal orientationforHFtags isfor the twoantennacoils(readerandtag)tobeparalleltoeachotherasshownbelowinfig4.UHFtagsareevenmoresensitivetopolarizationduetothedirectionalnatureofthedipolefields.Theproblem of polarization can be overcome to a large extent by different techniquesimplementedeitheratthereaderortagasshownintable4below.Table 4. Managing the problem of tag orientation
Reader -Antenna Tag UHF-AntennaCircularfieldpolarization HF - Antennas physically placed at
different locations with in different
orientations(XYZ) twoantennas90outofphasewitheach
other 3DTunnelreaders
UHFTwoantennaspolarized90outofphaseegMatricsdoubledipole
Fig 9. HF Tag orientation with different antenna configurations
Tagreadable
TagUn-readable
Reader
Antenna
1- D field,90 tag
orientations
7/27/2019 LaranRFID
14/30
14
Confident
Tag standards
Avery importantaspectofRFID technologyaretheassociatedstandardsandregulations.
They are designed to ensure safe operation with respect to other electricalandradioequipment,andguaranteeinteroperabilitybetweendifferentmanufacturersreadersandtags.Regulationsaremainlyconcernedwithreaderpoweremissionsandallocationoffrequencybands, whilst standards like the ISO (International StandardsOrganization) definetheAirinterfacecommunicationbetweenReader->TagandTag->Reader,andincludeparameterssuchas;
Communicationprotocol SignalModulationtypes
Datacodingandframes DataTransmissionrates Anti-collision (detectionand sorting ofmany tags intheReaderf ieldatthesame
time)
Reader
Antenna
3 - D field,
90 tag
orientations
Mux
Reader
Antenna2 - D field,90 tag
orientations
0 90
Phase splitter
7/27/2019 LaranRFID
15/30
15
Confident
ThehistoryofRFIDstandardsoverthelast10yearshasunfortunatelybeenfarfromideal,leadingtotoomanyvariationsandconfusion.ThesituationforthesupplychainandItemmanagementisnodifferentduetothetwoairinterfacestandardscurrentlybeingproposedbyISOandtheEPCglobal(seebelow).Someinitiativesareunderwaytotryandharmonizethetwointooneglobalstandard,whichwouldcertainlybetherecommendedwaytoensurethewidespreadadoption,andhighvolumesofRFIDtagswithinthesupplychain.
Table 5. ISO 18000 Information Technology AIDC Techniques-RFID for Item Management - Air
Interface
18000 1 Part 1 Generic Parameters for Air Interface Communications for Globally Accepted
Frequencies 18000 2 Part 2 Parameters for Air Interface Communications below 135 KHz
18000 3 Part 3 Parameters for Air Interface Communications at 13.56 MHz 18000 4 Part 4 Parameters for Air Interface Communications at 2.45 GHz
18000 5 Part 5 Parameters for Air Interface Communications at 5.8 GHz
18000 6 Part 6 - Parameters for Air Interface Communications at 860 930 MHz
Table 6. EPCglobal standards evolution:
Protocol Frequency Description
Class0 UHF Read-only,factoryprogrammed
Class0Plus UHF Read-writeClass1 HF,UHF WORM,(Write-once,readmany)
Class1,G2
UHF
WORM; can be used globally;merges Classes 0 and 1 andperhapsISO18000-6
Class2 UHF Aproposedread-writetagSource: RFID Journal Jan 2004 issue
Regional Regulations and Frequency Allocation
RFID tags and readers fall under the category of short range devices (SRDs), whichalthoughtheydonotnormallyrequirealicense,theproductsthemselvesaregovernedbythe laws and regulations which vary from country to country. Today, the only globallyacceptedfrequencybandistheHF13.56MHz.ForpassiveUHFRFIDtheproblemismuchmorecomplicatedasfrequenciesallocatedinsomecountriesarenotallowedinothers,duetotheirproximitytoalreadyallocatedbandsfordevicessuchasmobilephonesandalarms.ThisdiscontinuityhasresultedintheITU(InternationalTelecommunicationsUnion)dividingtheworldintothreeregulatoryregions,thesebeing;
REGION 1: Europe, Middle East, Africa and the former Soviet Union including Siberia
REGION 2: North and South America and Pacific east of the International Date Line
REGION 3: Asia, Australia and the Pacific Rim West of the International date line
7/27/2019 LaranRFID
16/30
16
Confident
The main regulatory bodies in the different regionsREGION1 :IntheUSA,theFederalCommunicationsCommission(FCC).
For UHF regulations see the FCC-Part 15 (15.249).whichcanbe foundat the followingwebsite:http://www.access.gpo.gov/nara/waisidx_01/47cfr15_01.html
AllocatedUHFband(902-928MHz), MaxPoweremission4WEIRP-FrequencyHopping
REGION2:InEurope,CEPT(EuropeanConferenceofPostalandTelecommunications)has
theresponsibilityoffrequencyassignmentandoutputpower.
ForUHF regulationsseepublicationERCREC70-73whichcanbe foundat thefollowingwebsitehttp://www.ero.dk/doc98/official/pdf/rec7003e.pdf
AllocatedUHFfixedband(869.3869.65MHz)
Poweremissionslimitedto500mWEIRP (expectedtobeenhancedto2Win2004) Readersmustoperatewithina10%dutycycleNoFrequencyorchannelhopping
,REGION3:InJAPAN,(MPHPT)MinistryofPublicManagement,HomeAffairs,Postsand
Telecommunication.
Regulation:JapaneseRadioLaw.ReferstoARIB(StandardsAssociationofRadioIndustriesandBusiness
JapanhasonlyrecentlyannouncedtheallocationofaUHFfrequencyat950MHz
ERP and EIRPThese aretwo reference parametersused todefine thepermittedradiated power inRFsystems.TheyareoftenquotedinRFIDreaderandtagspecifications.TheUStendstouseEIRPandEuropeERP.
TherelationshipbetweenthetwoisdefinedasEIRP=ERP*1.64MoreinformationaboutERPandEIRPcanbefoundinAppendixB-
7/27/2019 LaranRFID
17/30
17
Confident
RFID Readers
HFReader UHFEPCReader
Courtesy of SAMSYS
Readers or interrogators as theyare sometimes called, area keyelementin anyRFIDsystem,andwillthereforebepartoftheproductevaluationandselectionprocess.UpuntiltherecentsurgeindevelopmentsforthesupplychainandEPCtags,readersweremainly
usedin accesscontrolsystemsandother lowvolumeRFIDapplications,whichmeantthattheproblemoftreatingverylargenumbersoftagsandhighvolumesofdatawasnotsuchaserious issue. This is now of course all changing, and many reader manufacturers arestartingto developnextgenerationproductstohandletheapplicationproblemsthatwillbespecifictothesupplychainandEPCinfrastructure.
Main Criteria for readers
Operating Frequency (HF or UHF) some companies are developing Multi-frequencyreaders
ProtocolAgilitySupportfordifferentTagProtocols(ISO,EPC,proprietary)Most
companiesofferMulti-protocolsupport,butdonotsupportall!
Differentregionalregulations
-UHFfrequencyagility902930MHzintheUSand869MHzinEurope-PowerRegulations:4WattsintheUSand500mWinEurope
-ManageFrequencyHoppingintheUSandDutyCycleinEurope
Networkingtohostcapability:- TCP/IP-WirelessLAN(802.11)
-EthernetLAN(10baseT)
-RS485
Abilitytonetworkmanyreaderstogether- viaconcentrators
-viamiddleware
AbilitytoupgradethereaderFirmwareinthefield - viainternet
-viaHostinterface
Managingmultipleantennas- Typically4antennas/reader
7/27/2019 LaranRFID
18/30
18
Confident
- Howantennasarepolledormultiplexed
Adaptingtoantennaconditions -Dynamicauto-tuning
Interfacetomiddlewareproducts
DigitalI/Oforexternalsensorsandcontrolcircuits
Handheld Readers
Thesereadersareusedformanualinterventionwhereatagmayneedtobechecked,oreven updatedoff line. Industrial grade products for HFexist today from companies likePSIONTEKLOGIX.UHFproductsdoexist,butaremainlyeitherbasedaroundcommercialPDAdevices,whichalthoughtheyfunction,arenotclassedasindustrialgradeproducts.
RFID enabled HF Hand Held reader - Courtesy of PSION TEKLOGIX
RFID Label Printers
RFIDcompatiblelabelprintersaredesignedtoprogramdataintothepaperlabel-tags,as
theypassthroughthemachinefornormalprinting.TheprinterhasaninbuiltUHForHF(orboth)reader,capableoffirstrunningabasicfunctionalitycheckonthetag,forwhichifitfails,proceedstoprintavisiblerejectsignonthetagspapersurface.Tagswillneedtohavethecorrect reel format for specific printers. RFID label printers like the one shown fromPRINTRONIXbelowarecapableofprintingandprogrammingatanaveragethroughputof1.5labels/s,dependingonthelengthofthelabel.
Courtesy of PRINTRONIX
7/27/2019 LaranRFID
19/30
19
Confident
Reader AntennasInanRFIDsystem, reader antennasare often themost tricky part todesign in. For low
powerproximityrange(
7/27/2019 LaranRFID
20/30
20
Confident
RFID technology in the Supply chain
Definition of the Supply Chain.
The supply chain is a complex multi-stage processwhich involveseverythingfrom theprocurementofrawmaterialsusedtodevelopproducts,andtheirdeliverytocustomersviawarehousesanddistributioncenters.Supplychainsexistinbothservice,manufacturingandretailorganizations.Although,thecomplexityof thechainmayvarygreatlyfromindustryto
industryandfirmtofirm.Supplychainmanagement(SCM)canbeseenasthesupervisionofinformationand financesofthesematerials,astheymovethroughthedifferentprocesses,bycoordinatingandintegratingtheflowswithinandamongthedifferentcompaniesinvolved.Theefficiencyofthesupplychainhasadirectimpactontheprofitabilityofacompany.Itisnosurprisethereforetofindthatmanylargecorporatecompanieshavemadeitakeypartoftheirstrategy,andinvestedheavilyinsoftwaresystems(ERP,WMS..)andITinfrastructuredesignedtocontrolinventory,trackproductsandmanageassociatedfinance.
How will RFID help improve supply chain efficiencyRFIDwillbringanewdimensiontosupplychainmanagementbyprovidingamoreefficientwayofbeingabletoidentifyandtrackitemsatthevariousstagesthroughoutthesupplychain.Itwillallowproductdatatobecapturedautomatically,andthereforebemorequicklyavailableforusebyotherprocessessuchasASN,stockmanagementandrealtimebilling.
Comparison of Bar codes and RFIDBarcodesarepredominatelyusedtodayforidentifyingandtrackingproductsthroughoutthesupplychain.Eventhoughtheycanachieveefficienciesintheorderof90%,therearestillanumberofdeficienciesinthetechnology,forwhichRFID,isabletoprovideabettersolution
andfurtheroptimization.
Barcodedef iciency RFIDimprovedsolu t ionLineofSightTechnology AbletoScanandreadfromdifferentanglesand
throughcertainmaterials
Unable to withstand harsh conditions (dust,corrosive),mustbecleanandnotdeformed
abletofunctioninmuchharsherenvironments
NopotentialforfurtherTechnologyadvancement Technology advancement possible due to newchipandpackagingtechniques
Can only identify items generically and not asuniqueobjects
EPCcodewillbeabletoidentifyuniquelytypicallyup-to2
96items
Poortrackingtechnology,laborintensiveandslow Potentialto trackitems inreal timea theymovethroughthesupplychain
The main benefits of RFID in the supply chain.EventhoughRFIDapplicationsarestillattheearlystagesofdeployment,manycompaniesrunningpilotsystemshavebeenabletodemonstratesomeofthesignificantbenefitsthatRFIDpromises.Thereisnodoubtthatmorewillbediscoveredastheindustryadoptsthetechnologyonawiderscale.Thefollowingareexamplesofwhathasbeenidentifiedsofarbythedifferentstudiesandtests/pilotsrecentlycompletedwithinthesupplychain.
7/27/2019 LaranRFID
21/30
21
Confident
AdvancedShipp ingNot ices(ASN)
RFIDisabletoautomaticallydetectwheneitherapalletorshipmenthasleftthewarehouseorDistributionCenter.ThiswillallowtonotonlygenerateanelectronicASNand notify the recipient, but also tobill clients inreal time insteadofwaitinguntiltheendoftheweekormonth,anddoingabatchoperation.
Shrinkage
Oneofthemajorproblemsinthesupplychainisproductlossorshrinkage,which
can account for anything from 2 to 5 % of stock. The causes mayvaryfrommisplacedorders,employeeandcustomertheftorinefficientstockmanagement.RFIDwithitssuperiortrackingandidentificationcapabilitywillbeableto localizewherelossesareoccurring.
ReturnedGoods
Fullvisibilityandautomationcanbepotentiallyachievedonreturnedgoodstherebyreducingfraud.
Anti -counte rf ei t Illegalduplicationandmanufactureofhighvalueproducts,isoneoftheindustries
mostwellknownproblems.Byintegratingatagintoitems,forexamplethebodyofanexpensiveladieshandbag,RFIDhasthepotentialtoauthenticateaproduct,andcombatthesaleoffalsegoodsontheblackmarkets.
SupplyChaineff iciencyRFID will enable the traceability and reduction in the numberof discrepanciesbetweenwhatasupplierinvoiced,andwhatacustomeractuallyreceived.
Improvedstockmanagement Managingstockisthekeypriorityformanyretailers.Studieshaveshownthatonaverage,productsarenotonthestoreshelves7%ofthetimeduetoinefficiencies
in stock management, which means of course a potential purchase loss.ImplementingRFIDattheitemlevelandonshelveswillgiveanautomaticwayofknowingandmanagingstocklevels.Howeverinordertoachievethisonalargescale,itisrecognizedthat tagswillhavetocomedowninpricetoaround5centsorless,andreaderstoaround100USD.
ReductioninlaborcostsAt DC s (Distribution Centers) labor accounts for nearly 70% of costs. It isestimated that RFIDcould reduce this bynearly 30%by removingtheneedformanualinterventionanduseofbarcodeswhenloadingcasesorstockingpallets.
7/27/2019 LaranRFID
22/30
22
Confident
The EPC TM Electronic Product Code
At theheart of the currentRFIDbasedtechnologydrive to improvesupplychainefficiencyandreduceoperatingcosts,isTheEPC(ElectronicProductCode).WithoutitanditsmanygiantindustrialbackerslikeWal-Mart,RFIDinthesupplychainwouldstillbewhereitwas5yearsago,atechnologylookingforabusinesscase.Themomentumhasbeentremendous,andhassparkedoneoftheraretechnologyrevolutionswhereendusercompaniesareinthe
drivingseat.
EPC OriginsIn October 1999 the Auto-ID center was created in the Department of MechanicalEngineeringbyanumberofleadingfiguresatMIT.ThepotentialbenefitsofRFIDtagshadbeenidentifiedlongbefore,whatwasstoppingtheadoptionofthetechnologyinthesupply
chainwasthecostofthetags.TheAutoIDrecognizedthatinordertosolvethisproblem,tagsneededtobeassimpleaspossible,andactinsteadaspointerstoinformationheldonserversinthesamewayasinformationisstoredontheinternet.Thisleadto the ideaoftheEPC(ElectronicProductCode)whichwouldprovidefastanddetailedinformationofproductsanywhereinthesupplychain.Thegoalhowever,wasnottoreplacebarcodes,butrathertocreateamigrationpathforcompaniestomovefrombarcodetoRFID.
TheAuto-IDCenterofficiallyclosedonOctober26th,2003.Thefinalboardmeetingwasheldin Tokyo, Japan. The Center had completed its work and transferred its technology toEPCglobal(www.epcglobalinc.org),whichwilladministeranddevelopEPCstandardsgoingforward.
EPC layoutThecodeissimilarto theUPC(UniversalProductCode)usedinbarcodes, andrangesfrom64bitsto256bitswith4 distinct fieldsdescribedbelowin fig10..Whatsets theEPC
apartfrombarcodesisitsserialnumberwhichallowstodistinguishtheuniquenessofanitem,andtrackitthroughthesupplychain.
Fig 10. Layout of an EPC which is 96 bits in length
Header(0-7)bitsTheHeaderis8bits,anddefinesthelengthofthecodeinthiscaseO1indicates
anEPCtype1numberwhichis96bitsinlength.TheEPClengthrangesfrom64to256bits.
7/27/2019 LaranRFID
23/30
23
Confident
EPCmanager(8-35)bitsWilltypicallycontainthemanufactureroftheProducttheEPCtagisattachedto
ObjectClass(36-59)bits ReferstotheexacttypeofproductinthesamewayaanSKU(StockKeepingUnit)
SerialNumber(6096)bits
Providesauniqueidentifierforupto296products
EPC infrastructure
fig. 11 The basic steps of EPC infrastructure
An EPC is stored into an RFID tag/label
and attached to an item Tag Tag Sensor
Reader scans and reads the EPC Sends Data to a computer running middleware
Reader
Temp.
ePC s
Filter Data Query ONS (Object naming Service)
Manage Readers
Middleware/Savant
ID
Internet PML server
ONS database maps the EPC to a URL
URL points to the location whereinformation is stored using PML
ONS
Database
PML data
7/27/2019 LaranRFID
24/30
24
Confident
EPC infrastructurewill allow immediate access to information, whichwillnotonlyoptimizeexistingservicessuchASN,butalsohavethepotentialtocreatenewservices,forexample;aretailercouldautomaticallylowerpricesastheexpirydateapproaches,oramanufacturercould recall a specific batch of products duetohealthconcerns,andifneededpinpointsourceoftheproblemdowntoauniqueproduct.
Middleware or Savant Software
ThesheerpotentialvolumeofdatacreatedbybillionsofEPCtagswouldveryquicklygrindmost existing companies enterprise software and IT infrastructure to a standstill within amatterofminutes.TheanswertothisproblemismiddlewareorSavants.RFIDsavantsserveasasoftwarebufferwhichsitsalmostinvisiblebetweentheRFIDreaders,andtheserversstoring the product information. Itallowscompaniesto process relativelyunstructuredtagdatatakenfrommanyRFIDreaders,anddirectittotheappropriateinformationsystems.Savantsareabletoperformmanydifferentoperations,suchasmonitortheRFIDreader
devices,managefalsereads,cachedataandfinallyqueryanObjectNamingService(ONS).
Object Name Service (ONS)
ONSmatches theEPC code toinformationabout the product viaa queryingmechanismsimilartotheDNS(DomainNamingsystem)usedintheinternet,whichisalreadyproventechnologycapableofhandlingthevolumesdataexpectedin anEPCRFIDsystem.TheONSserverprovidestheIPaddressofaPMLServerthatstoresinformationrelevanttotheEPC.
Physical Markup Language (PML)WhilsttheEPCisabletoidentifytheindividualproduct,therealusefulinformationiswritteninanewstandardsoftwarelanguagecalledPhysicalMarkupLanguage.PMLitselfisbasedon the widely used and accepted extensible markup language (XML), designed as adocumentformattoexchangedataacrosstheinternet.Itisnotsurprisingtherefore,withsomuchof the infrastructurefor EPCbeingborrowedfrom theinternet(DNS,XML..), that it isoftenreferredtoas theinternetofthings.
PMLisdesignedtostoreanyrelevantinformationaboutaproduct;forexample,
(1) Locationinformation e.g., tag X was detected by reader Y, which is located atloadingdockZ;
(2) Telemetry information [Physical properties of an object e.g., its mass; Physicalpropertiesoftheenvironment,inwhichagroupofobjectsislocated,e.g.,ambienttemperature];
(3) Compositioninformatione.g.,thecompositionofanindividuallogisticalunitmadeupofapallet,casesanditemsTheinformationmodelwillalsoincludethehistoryofthevariousinformationelementslisted above e.g., a collectionof the various single
locationreadingswillresultinalocationtrace.(4) manufacturingandexpirydates
7/27/2019 LaranRFID
25/30
25
Confident
How the EPC will automate the supply chain (courtesy of EPCglobal and XPLANE) Atthep roducta ssembly-p ackagingl ine.
1.Each Item contains an RFIDtagwhich has a uniqueidentifiercalledanEPCstoredinitsmemory.
2.Items can now be automatically and cost-effectivelyidentified,countedandtracked.Casesand pallets canalsocarrytheirownuniquetags.3.As pallets leave the manufacturer, an RFID readerpositionedattheloadingdockdoorbeamsaradiowavethatwakesupthetags.
4.a) TheTagscommunicatetheirindividualEPCs
tothe reader,which rapidlyswitches themonandoffinsequence(anti-collision),untilallareread.
b) The reader sends the EPC to a computer
calledSavantTM,whichinturn,sendstheEPCovertheinternettoanObjectNamingService(ONS) database, which produces acorrespondingaddress.TheONSmatchestheEPC toanother server (PML), whichhas thefulldetailsabouttheproduct.
c) ThePML(PhysicalMarkupLanguage)server
stores details about the manufacturersproducts.Becauseitknowswheretheproductwasmade, ifan accident involving adefectarises, the source of the problem can betrackedandtheproductsimmediatelyrecalled.
Savant ONS server PML serverComputer
EPC: Look under Can of Cherry
Fxyzz3t0nn;4x;CC Super Cola Inc Soda, shippedFrom Boston,MA
5. At theDistr ibuti onCenterIftheunloadingareacontainsanRFIDreader,theresno need to open the packages and examine theircontents.ASAVANTprovidesacargolist,andthepalletisquicklyroutedtotheappropriatetruck.
6. At theRetailSto re As soon as it arrives , retail systems are updated toinclude every item. In this way storescan locatetheirentireinventoryautomatically,accuratelyandatlowcost.Reader enabled smart shelves can automaticallyordermoreproduct from thesystemandthereforekeepstocktocost-effectiveandefficientlevels.
7/27/2019 LaranRFID
26/30
26
Confident
Security in RFID Systems
RFIDtagsusedinthesupplychainwillcontaindatarangingfromsimpleIDnumbers(EPC),
tomoreimportantinformationaboutaproduct.Forexampleinthehealthindustry,itcouldbe
thebloodtypeofasample.Themaingoalofanysecuritysystemdesignedtoprotectdatastoredinmediumssuchastags,computerdiskdrives,orsmartcardsisbasicallytopreventanyunauthorizedpersonfrombeingabletoeither;
a) Obtainaccessandlearnthedatacontentsb) Obtainaccessandmodify/corrupt/erasethedatacontentsc) Copythedatacontentstoasimilarstoragedevice(duplicate)
In a completesystem, security of data asdefined abovenot only involves the storagemedium,butalsohowdataiscreatedandtransferredfromahosttothemedium(orvice
versa).Forexample,whenanengineerbrokethesecurityofaFrenchbankcreditcardafewyearsago,hediditnotbycompromisingthechipsecurity,butbyhackingthereaderterminal.
Thefollowingarescenariosthatcouldhappeninthesupplychain.
1) IndustrialSabotagesomebodywithagrievanceagainstacompanydecidestostartcorruptingdataintagsbyusingahandhelddevice,anderasingormodifyingthecontents.
2) IndustrialEspionage Aratherunlawful competitorwouldliketoknowhowmany,
andwhattypeofproductsarebeingmanufactured,andshippedbyyourcompany.Hecouldpossiblyachievethisinthefollowingways
i. Eavesdropping l istening in on longer range communication
systemslikeUHFwhichbroadcastsignals(albeitveryweak)upto
100meters someprotocolshave abasic securitywhichensuresthattheIDNisnevertransmittedcompletelyinonestream.ii. PlacingboguswellconcealedreaderslinkedtoaPCsomewherein
theproximityofthetagsmovingthroughtheproductionlineiii. Usinghandhelddevices
3) Counterfeiting Beingabletoreadorinterceptdatabeingwrittenintoatagwhich
uniquelyidentifiesorcertifiesaproduct.Oncethedataisknown,similarread/writetagscouldbepurchasedandupdatedwiththeauthenticdata,thuscreatingtherealpossibilityofcounterfeitingproductswhicharesupposedtobeprotectedbyatag.
Alltheabovescenariosarepotential risksifnosecurityisimplementedinthetagandreader.The importance attached to protecting data in the supply chain will depend on theapplication, andthe companies strategy towards security. In some cases legislationwill
imposeit.Ofcoursebarcodeswhichareusedtoday,canbeeasilyread,decrypted,andevendestroyed,butnotonthewide-spreadandautomaticscalepossiblewithRFID.Eventhesimplestsecuritycostssiliconarea,andthereforewillimpactonthefinaltagprice.This goes against the current trendof trying to produce the smallest, andcheapest tagpossible.Everycompanyisthereforefacedwiththistradeoffbetweencheaperunsecuredtags,andthepotentialsecurityriskstheyentail.
7/27/2019 LaranRFID
27/30
27
Confident
Conclusion
The interest in RFID as a solution to optimize further the supply chain is gatheringmomentumataneverincreasingpace,withmoreandmorecompaniesannouncingtrials
andmandatestotheirsuppliers.Thetechnologyisstillnotyetwidelyunderstoodorinstalledin the supply chain, and cost/ROI models far from established. Many companies arethereforenowfacedwith thedifficultchoicein decidingwhethertheyshouldbelookingatRFIDnow,orwaitinguntildeploymentismorewidespread.ThereisastrongtemptationtogetcarriedawaybyallthehypeandpublicitysurroundingRFIDtoday,whichisallthemorereason tohave asenseofrealityastowhatitmeanstointegrateRFID,whyyourcompanywould want to do it , and what would be the acceptable time frames for the perceivedbenefits.InvestinginRFIDonthescalerequiredforthesupplychainwillbeaverycostlyexercise,andifnotmanagedcorrectlycouldleadtounnecessarylosses.Thetechnologyisnotplugandplay,andwillhavetobeadaptedtoeachapplication.Furthermore,implementingan
infrastructuretosupportEPCdatacouldhaveaconsiderableimpactonexistingITsystems.EvenatthisearlystageintheadoptionofRFIDinthesupplychain,thereisenoughevidencetodemonstratethatwiththerightstrategies,RFIDwillbringbenefits.Thetechnologyisheretostay,andwilleventuallybecomewidelyadoptedwithinthesupplychain.Thosecompaniesprepared to invest now will not only become theearly winners,butalsobenefitfromtheexperiencebybeingcapableofextendingtheapplicationofRFIDintonewservices
About the Author.Steve Lewis
IsthefounderofLARANacompanysetuptoprovideprofessionalconsultingandmarketingservicesforRFIDtechnology.QualifiedwithamicroelectronicsdegreefromtheuniversityofWales,hehasacombinedexperienceofover20 years in thesemi-conductorandRFIDindustries, having held positions in IC silicon design, product marketing, and businessdevelopment.Heisaveteranoftwosiliconstartups,ES2andINSIDETechnologies,andhas spent the last 8 years working in a wide range of RFIDapplications andmarketsincluding;VehicleKeylessEntrysystems,AccessControl,IDandtransport.
ContactDetails
Email:[email protected]
Website:www.laranrfid.com
7/27/2019 LaranRFID
28/30
28
Confident
Appendix A
More about Near and Far fields
Up until recently, nearly all passive RFID systems in production were either LF or HF.Designing systems at these frequencies was based on a few equations relating to
inductance,mutualinductanceandtheknowledgethatthemagneticfieldreducedrapidlywith distance (1/r
3). With the recent explosion of RFID in the supply chain came the
recognition thatUHF wouldallow longer read range,andfaster detectionof many tags.EngineersusedtodevelopingLFandHFsystems,arenowfacedwithacompletelydifferentconceptandsetofchallengeswithUHF.OneofthenewconceptsencounteredwhenlookingatUHFforthefirsttime,istheideaoftwo distinct and different regions around an antenna called the near fieldand far field.ElectromagnetictheorydevelopedbyMaxwellinthe19
thcenturyshowsthatanyconductor
(e.g.antenna)suppliedwithanalternatingcurrentproducesavaryingmagneticfield(H-field)whichinturn,producesElectricFieldlines(E-field)inspace.Thisistermedthenearfield.
InthenearfieldboththeEandHfieldsarerelativelystaticwithnopropagation.Theyonlyvary instrengthas thecurrentvaries ,withthemagneticfluxof theH-fieldcomingoutfromtheantenna,andgoingbackin,andtheE-fieldemanatingout-wards.Maxwellalsoprovedthatbeyondthisquasi-staticnear field,both theE-fieldsandH-fieldsatacertaindistance,detachedthemselvesfromtheconductorandpropagatedintofreespaceasa combined
wave,movingatthespeedoflightwithaconstantratioofE/H=120or377.(Ohmsareusedbecause theE-fieldismeasuredinvoltspermeterV/MandtheH-fieldinampspermeterA/M.).Thepointatwhichthishappensiscalledthe farfield.
Fig A-1 Transition region between near and far fields
Becausechangesinelectromagneticfieldsoccurgradually,theboundarybetweenthetwofieldsisnotexactlydefined.Thedistanceatwhichthetwoseparateoutfromthesourceasafixedplanewavecanbemodeledinanumberofways.Thesimpler2-regionmodelshownin
figA-2givesadistanceof /2wherethefalloffis1/r3(dominantfield)and1/r
2inthenear
fieldregion,and1/r inthe far field. The 3-regionmodelismuchmorecomplicatedwithatransitionregionwherecomponentsdecayas1/r,1/r
2and1/r
3..
r /0.1 1.0 10
10
100
1000
10000
Magnetic field
Electric field
Transitional field
Plane waveWave impedence,
OhmsZo = 377Ohms
r
0.011/2
Near Field Far Field
5.0
7/27/2019 LaranRFID
29/30
29
Confident
Fig A-2 Different Region models
Thedistancemeasureof/2canbeconsideredasareferencepoint,whereifthetagisinaregionmuchlessthan1/20wavelengths,thenwearedefinitelyinthenearfield.Fordistancesgreaterthan5wavelengthswearedefinitelyinthefarfield.ThisisshowninTableA-1
Table A-1 Near and Far field limits
Band NearFieldRegion FarFieldRegion
LF 12Km
HF 110mUHF 1.65m
Microwave 0.25cm
ApplyingsomepracticalsensewecandrawthefollowingconclusionsforRFIDtags
1) AtLF,tagsalwaysworkinthenearfield2) Atmicrowave,tagsalwaysworkinthefarfield3) AtHF,tagsworkinthenearfieldbutsomeintermediate(transition)fieldcomponents
areeffectiveatantennaemissionmeasurementranges.4) AtUHF,passivetagsoperateinthetransitionfieldareaortheFarfield
1/r 1/r 1/r 1/r1/r.1/r
Dominant
Terms
in the region
3- REGION MODEL 2- REGION MODEL
FAR FIELD NEAR FIELD NEAR FIELD FAR FIELD
TRANSITION
ZONE
7/27/2019 LaranRFID
30/30
Confident
APPENDIX B
EIRP and ERP Power Emissions
EIRP(EquivalentIsotropicRadiatedPower)EIRPrefers totheproductof thepowersuppliedtotheantennaandtheantennagaininagivendirectionrelativetoanisotropicantennaAnIsotropicantennaisonewhichradiatespowerequallyinalldirections(e.gasphere)ERP(EffectiveRadiatedPower)ERPreferstotheproductofthepowersuppliedtotheantenna anditsgainrelativetoahalf-wavedipoleinagivendirection.
EIRP=ERPx1.64
Comment:Itwouldmakemoresenseofcoursetojusthaveoneharmonizedpowerterm,eitherERPorEIRP,howeveras isoften the casewith International standards, its not always easy toachieve.
Here is an extract from a recent BloonstonLaw Telecom Update from the FCC on thissubject.
ERP/E IRP issues:
Although theCommissionrecommended in the 2000BiennialReviewReportthatarule-makingproposalbeinitiatedtoconsiderusingequivalentisotropicallyradiatedpower(EIRP)exclusively in Commission rules, it now tentatively concludes that the costs ofimplementation and potential for greater confusion that would likely be associated withmaking a wholesale conversion from effective radiated power (ERP)limitsto EIRPlimits,
outweigh the potential benefits to those licensees whodonotpossess thescientificorengineeringexpertisetodistinguishbetweenthetwostandards.Additionally,theagencystates that theconversion fromERPtoEIRPisasimplecalculation.Such a change in the rules would require extensive modif ications, not only for theCommission(e.g.,reprogrammingtheULS,amendinginternationalagreementsnegotiatedin termsof ERP,etc.),butalso for licensees, frequency coordinators,manufacturers,and
othersinthewirelessindustry.Moreover,becauseanEIRPlimitisalwaysalargernumberthantheequivalent ERP limit, theFCC believes that restating all ERPlimitsas EIRPlimitscouldlikelycausesomeentities(e.g.,licensees,frequency;coordinators,etc.)tomistakenlythinkthattheCommissionhasincreasedthepermittedpower