CBRSAlliance3855SW153rdDriveBeaverton,[email protected]©2018CBRSAllianceAllRightsReserved
CBRSAllianceIdentifierGuidelinesforSharedHNI
CBRSA-TR-0100
V1.0.0
November27,2018
CBRSAlliance3855SW153rdDriveBeaverton,[email protected]©2018CBRSAllianceAllRightsReserved
LEGAL DISCLAIMERS AND NOTICES THIS SPECIFICATION IS PROVIDED "AS IS," WITHOUT ANY REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS, IMPLIED, OR STATUTORY; AND TO THE MAXIMUM EXTENT PERMITTED BY LAW, CBRS ALLIANCE, AS WELL AS ITS MEMBERS AND THEIR AFFILIATES, HEREBY DISCLAIM ANY AND ALL REPRESENTATIONS AND WARRANTIES, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY, TITLE, NON-INFRINGEMENT, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, OR RELIABILITY, OR ARISING OUT OF ANY ALLEGED COURSE OF PERFORMANCE, DEALING OR TRADE USAGE. ANY PERMITTED USER OR IMPLEMENTER OF THIS SPECIFICATION ACCEPTS ALL RISKS ASSOCIATED WITH THE USE OR INABILITY TO USE THIS SPECIFICATION. THE PROVISION OR OTHER PERMITTED AVAILABILITY OF OR ACCESS TO THIS SPECIFICATION DOES NOT GRANT ANY LICENSE UNDER ANY PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS ("IPR"). FOR MORE INFORMATION REGARDING IPR THAT MAY APPLY OR POTENTIAL AVAILABILITY OF LICENSES, PLEASE SEE THE CBRS ALLIANCE IPR POLICY. CBRS ALLIANCE TAKES NO POSITION ON THE VALIDITY OR SCOPE OF ANY PARTY'S CLAIMED IPR AND IS NOT RESPONSIBLE FOR IDENTIFYING IPR. TO THE MAXIMUM EXTENT PERMITTED BY LAW, UNDER NO CIRCUMSTANCES WILL CBRS ALLIANCE, OR ANY OF ITS MEMBERS OR THEIR AFFILIATES, BE LIABLE FOR DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, SPECIAL, EXEMPLARY, PUNITIVE, OR OTHER FORM OF DAMAGES, EVEN IF SUCH DAMAGES ARE FORESEEABLE OR IT HAS BEEN ADVISED OR HAS CONSTRUCTIVE KNOWLEDGE OF THE POSSIBILITY OF SUCH DAMAGES, ARISING FROM THE USE OR INABILITY TO USE THIS SPECIFICATION, INCLUDING WITHOUT LIMITATION ANY LOSS OF REVENUE, ANTICIPATED PROFITS, OR BUSINESS, REGARDLESS OF WHETHER ANY CLAIM TO SUCH DAMAGES SOUNDS IN CONTRACT, WARRANTY, TORT (INCLUDING NEGLIGENCE AND STRICT LIABILITY), PRODUCT LIABILITY, OR OTHER FORM OF ACTION.
CBRSAlliance3855SW153rdDriveBeaverton,[email protected]©2018CBRSAllianceAllRightsReserved
Table of Contents 1. Introduction ...................................................................................................................11.1. Scope..............................................................................................................................................................11.2. References...................................................................................................................................................11.3. Glossary........................................................................................................................................................1
2. Goals .............................................................................................................................3
3. Problems with Non-Uniqueness for Key Identifiers .....................................................43.1. HNI..................................................................................................................................................................43.2. IBN(partofIMSI).....................................................................................................................................43.3. CBRS-NID–NetworkID.........................................................................................................................53.4. ECGI................................................................................................................................................................53.5. GloballyUniqueMMEIdentity(GUMMEI)[7].............................................................................63.6. PSP-ID(ParticipatingServiceProvider).........................................................................................73.7. TrackingAreaIdentity(TAI)[7]........................................................................................................8
4. Deployment Considerations ..........................................................................................84.1. SystemsNotNeedingUniqueness.....................................................................................................84.2. ProblemswithSelf-AssignedIdentifiers........................................................................................94.3. IdentityAdministrators.........................................................................................................................94.4. BusinessProcess....................................................................................................................................104.5. IdentifierManagementPrinciples..................................................................................................104.6. ProcessImplementation.....................................................................................................................11
Annex A. ECGI Uniqueness and E911 Detailed Rationale ...........................................13
Annex B. Revision History ............................................................................................15
Copyright©2018CBRSAlliance|AllRightsReserved
1
1. Introduction 1.1. Scope
SuccessfulbroaddeploymentofLTEnetworksinCBRSspectrumrequiresproperuseofLTEnetworkanddeviceidentifiers.
ThisdocumentisaTechnicalReportthatisintendedforCBRSLTEoperatorsthatwillbeusingaSharedHNIandnotforoperatorsthathavetheirownHNI.
ThesubjectofthisdocumentisanetworkbasedonCBRSAlliancespecifications[2][6]thatusesaSharedHNI(SHNI)astheCBRS-I.Suchanetworkdeploymentisreferredtoasa“SHNINetwork”inthisdocument.
1.2. References
[1] ATISIOC.IMSIGuidelinesforSharedHNIforCBRSRange,http://www.atis.org/01_committ_forums/ioc/Docs/IMSI-CBRS-Guidelines.pdf
[2] CBRSAlliance.NetworkServicesStage2and3Specifications.CBRSA-TS-1002.
[3] MulteFireAlliance.ArchitectureforNeutralHostNetworkAccessModeStage2.MFATSMF.202.
[4] 3GPP.Non-Access-Stratum(NAS)protocolforEvolvedPacketSystem(EPS);Stage3.TS24.301.
[5] GSMAEmbeddedMobileGuidelines–NetworkAspects,Version3.https://www.gsma.com/iot/wp-content/uploads/2012/03/GSMA-Whitepaper-Embedded-Mobile-Guidelines-Release_3-Network-Aspects1.pdf
[6] CBRSAlliance.NetworkServicesUseCasesandRequirements.CBRSA-TS-1001.
[7] 3GPP.Numbering,addressingandidentification.TS23.003.[8] 3GPP.S1ApplicationProtocol(S1AP).TS36.413.
[9] MulteFire.Non-Access-Stratum(NAS)protocolforEvolvedPacketSystem(EPS);Stage3.MFATS24.301.
1.3. Glossary
Term Definition
BSSID BasicServiceSetIdentifier
CBRSA CBRSAlliance.http://cbrsalliance.org
CBRS-NID CBRSNetworkID(27bits).
Copyright©2018CBRSAlliance|AllRightsReserved 2
CSG ClosedSubscriberGroup.GSM/LTEconceptre-usedbyCBRSAasCBRS-NID.See[2]and[7].
DSC DiameterSignalingController
ECGI E-UTRANCellGlobalIdentifier,composedofHNI+MacroeNBID(20bits)+CellID(8bits).See[8].
ESQK EmergencyServicesQueryKey
GUMMEI GloballyUniqueMMEID(48bits).
HNI HomeNetworkIdentifier:MCC+MNC(6decimaldigits1).
IBN IMSIBlockNumber(4decimaldigits).
IMSI Subscriptionnumber(15decimaldigits).,see[7].ForSharedHNI:SHNI+IBN+UIN,see[1].
IMSI-A USIMSIAdministrator.http://imsiadmin.com
MCC MobileCountryCode(3decimaldigits).AssignedbyITU-Ttoacountry
MME MobilityManagementEntity
MMEC MMECode(8bits)
MMEGI MMEGroupID(16bits)
MMEI MMEID=MMEGI+MMEC
MNC MobileNetworkCode(2-3decimaldigits).AssignedbynationalIMSIadministratortooneoperatoror,inthecaseofSharedHNI,tomultipleCBRS-Ioperators
PLMN-ID SynonymforHNI.
PSP-ID ParticipatingServiceProviderID.HNI,OID,domainnameora24bitreductionofalongeridentifier
1 Decimaldigitsareencodedas4-bitBCDunlessotherwisespecified.
Copyright©2018CBRSAlliance|AllRightsReserved 3
SHNI SharedHNI.AnHNIdesignatedbyATISIOCforCBRSoperationthatisrecognizedbyCBRSsystemsasshared.Thefirstsuchassignmentis315-010.
SHNINetwork
AnetworkthatbroadcastsaSharedHNIasitsidentity(supplementedbyaCBRS-NIDforuniqueness).
TAC TrackingAreaCode(16bits).
TAI TrackingAreaIdentity.SHNI+TAC
UIN UserIDNumberwithinIMSI(5decimaldigits).
2. Goals OneofthepurposesoftheCBRSAllianceistocoordinatetheequipmentandactivitiesofmanufacturers,operators,SASprovidersandotherparticipantsintheCitizensBroadbandRadioService(CBRS)sharedspectrumecosystem,tospeedtimetomarket,reducecost,andincreasethereliabilityandinteroperabilityofsystemsbasedonLTEstandards.OneofthewaysthesegoalscanbeaccomplishedisthroughthedevelopmentofspecificationsorguidelinesspecificallyorientedtooperationintheCBRSspectrumthatarenotaddressedby3GPPorotherorganizations.Thisdocumentpresentsbackgroundinformationandrecommendationsrelatedtothecoordinationofthefollowingimportantidentifiersfornetworkanduserequipment(UE),andexplainswhytheybenefitfrombeinggloballyorlocallyunique:
• SharedHNI.Aspecificcombinationof3-digitMobileCountryCode(MCC)and3-digitMobileNetworkCodethatindicatesthatthenetworkisusingaSharedHNI(SHNI).Thiscodeissharedbymanyoperators,andisthereforenotuniquetoasingleoperator.Atpresentthereisjustonesuchnumber(315-010),buttherecouldbemoreinthefuture.
• CBRS-NID.TheNetworkIDisbasedontheLTECSG-ID(ClosedSubscriberGroupID)andsupplementstheSharedHNI.TogethertheycanprovideagloballyuniqueidentityforasingleSHNINetwork.
• IMSI.AnIMSIisthe15-digitgloballyuniquewirelesssubscriptionidentityandisstoredintheSIM/UICCinsertedorembeddedinaUE.FordevicesprovisionedforanSHNINetwork,theSharedHNIwillbeusedintheIMSIasMCC+MNC.DeviceswithanIMSIbasedonanon-sharedHNIthatroamintoanSHNINetwork(e.g.NHN)couldcontinuetousetheirexistingIMSI[7].
• E-UTRANCellGlobalIdentifier(ECGI).EveryLTEbasestation(eNodeB)isintendedtobeuniquelyidentifiedbyanECGIthatiscomposedofPLMN-IDandCellID.FortheCBRSNetwork,theSharedHNIisusedasthePLMN-IDwithintheECGI[7].
Copyright©2018CBRSAlliance|AllRightsReserved 4
• MMEID(GUMMEI).EveryMobilityManagementEntityinanLTEsystemrequiresagloballyuniqueMMEID.BecauseitcontainstheSharedHNIasaprefix,GUMMEIvaluesmustbecoordinatedwithintheSharedHNI[7].
• TrackingAreaID(TAI)needstobelocallyunique,withnoneighboringsystemsusingthesamevalue[7].
Uniqueidentifiersareimportantincommunicationssystemsbecausecommunicationsystemsoftendonotfunctioncorrectlywithduplicateidentifiers.Forexample,itispossiblethattwomobiledeviceswiththesameIMSIwillnotworkproperlyandeventuallybothmaybeblacklisted(unabletoreceiveservice)afterfailingauthentication.Similarly,hardwareidentifierslikeIMEIarerequiredtobegloballyunique.
3. Problems with Non-Uniqueness for Key Identifiers ThissectionexaminestheuniquenessrequirementsofseveralkeyidentifiertypesthatareessentialtotheoperationofCBRSLTEnetworks.
3.1. Home Network Identifier (HNI)
NormallyanHNIisassignedtoasingleoperator,andtheoperatorisresponsibleformanagingtheuniquenessofIMSIcodesandotheridentifiersconstructedusingtheHNI.However,ATISIOChasmadeitpossibleforthenewSharedHNItobeusedsimultaneouslybyalargenumberofoperatorsintheCBRSecosystem.Coordinationoftherelevant“CBRSSharedHNI”identifiersdescribedinthisdocumentwillbeadministeredbytheCBRSAlliance[1].
3.2. IMSI Block Number (IBN)
EverysubscriberhasanIMSIstoredwithintheir‘smartcard’(UICC)orembeddedinthedevice(eUICC).Itisthe15-digitgloballyuniquewirelesssubscriptionidentityconsistingofHNI+MSIN(MobileSubscriptionIdentificationNumber).NormallyanoperatorisassignedanHNIforexclusiveuse,andisresponsibleforassignmentoftheMSINcodestosubscribers.
However,foraSharedHNI(SHNI),MSINisfurtherbrokendownintoIBN+UIN.ACBRSoperatorthathassubscribers(i.e.‘smartcards’orUICCforeachsubscription,whetherremovableorembedded)isresponsibleforobtainingatleastoneIBNfortheirexclusiveuse.TheSharedHNI+operator-specificIBNthenformsagloballyuniqueoperatoridentifier.
TheCBRSoperatorisresponsibleforcreatinguniqueidentifiersbyallocatingadifferentUINtoeachsubscriber/subscription.IftheCBRSoperatorfailstoobtainanoperator-specificIBNforitssubscribers,thentheglobaluniquenessoftheirIMSIsisnolongerguaranteed,andthefollowingproblemscanoccur:
• AuthenticationofthesubscriptionwillfailifthewrongMMEisqueriedbasedonthenon-uniqueIMSI.
• NetworkoperationswillfailwhentheIMSIisusedtoroutemessages(e.g.toanMME).
Copyright©2018CBRSAlliance|AllRightsReserved 5
3.3. CBRS-NID – Network ID
TheCBRS-NID(theLTEClosedSubscriberGroupID,CSG-ID)isessentiallyanextensiontotheSharedHNIthatcreatesacomposite,globallyunique,operatoridentity.TheuseofCSG-IDasCBRS-NIDisdescribedin[2].
TheCBRSAllianceplanstomaintainaregisterofCBRS-NIDcodesandensurethatanysinglecodeisonlyeverassignedtoasingleoperator2,thusachievingglobaluniquenessamongoperatorsusingtheCBRSAllianceCBRS-NIDcodes.
Ifanon-uniqueCBRS-NIDisusedbyonenetwork(Network‘B’)thatisthesameastheCBRS-NIDassignedtoanothernetwork(Network‘G’)thenamobiledevicefromNetwork‘G’encounteringNetwork‘B’canattempttoregisteronthisnetwork,andthemobile’sregistrationwillberejectedbyNetwork‘B’withe.g.,aCauseValueof3(IllegalUE)or8(EPSservicesandnon-EPSservicesnotallowed).ThemobilewillthenconsideritsUSIMasinvalid(see3GPPTS24.301[4]section5.3.7bandthemobilewillnotattempttoregisterwhenitlaterencountersitsownNetwork‘G’.Themobilewouldreturntonormalafterapowercycle,whentheUSIMisreplaced,orwhentimerT3245inthedeviceexpires(upto48hours)[4][5].
Toavoidthisproblem,CBRSAllianceTS-1002[2]recommendsusingCauseValue12(TrackingAreanotallowed)whenanATTACHREJECT,TRACKINGAREAUPDATEREJECTorSERVICEREJECTissenttoaUE.ThiswillallowtheUEtobeginanormalattachprocedureatalatertime.
Unfortunately,anunassociatedoperator,outsideoftheAlliance,couldusetheCBRSSharedHNIwithoutcoordinationwiththeAllianceandmightselectaNIDthathasbeenassignedtoanetworkbytheCBRSAlliance.TheCBRSAlliancewilltakeappropriateeffortstoavoidconflicts,e.g.,byfacilitatingtheassignmentofNIDsusedbynon-CBRSAlliancemembers.
3.4. EUTRAN Cell Global Identifier (ECGI)
TheECGIisagloballyuniqueidentifierforanLTEcellorsector,comprisedofHNIandCellIdentity.CellIdentityincludestheMacroeNBID.SeerequirementRAN-Share-005[6].TheECGIwillnotdistinguishbetweenmultipleCBSDsthatbroadcastthesamesystemparameters[7][8].DuplicateECGIsindifferentoperatornetworkscancausethefollowingproblems:
2 CBRS-NIDcodesshouldnotbere-used.Inthefuture,theIMSI-AmayassignadditionalHNIcodesandthereis
nowaytocorrelateNID(CSG-ID)withaspecificHNIwithinSIB-1.
9
MCC(3d) MNC(3d) IBN(4d) UIN(5d)
SHNI(6d) MSIN(9d)
IMSI(15d)
Copyright©2018CBRSAlliance|AllRightsReserved 6
• BrokenLTEAssumption.LTEspecificationsarebasedupontheassumptionthatECGIisgloballyunique.ItisimpossibletoruleoutthepossibilitythatproblemswilloccurwithduplicateECGIthatwerenotknowntotheauthorsofthisdocument.Thosethatareknownarelistedbelow.
• ErroneousE911callroutinganddispatch.Traditionally,adatabaseofECGIsismaintainedtoprovideanapproximatelocationandblocksofPSAProutingnumbers(ESQK)for9-1-1callswhenaGPSlocationisnotavailable(orbeforeaGPSlocationisavailable).DuplicateECGIscouldresultinthewronglocationorwrongroutingnumberbeingprovidedtothe9-1-1calltakersatthePSAPifthirdpartyorsharedinfrastructureisusedtointerprettheECGI.GiventhecomplexityofroutingtoE911PSAPsitismostlikelythattheconversionfromECGItoapproximatelocationtoroutingnumberisdonebyathirdparty.
• SloworinaccurateGPSpositioning.GPSpositioningsignificantlybenefitsinspeedandaccuracyfromaninitial‘reference’location(accuratewithinafewmiles)thatisnormallybasedontheknownlocationofeachbasestationasidentifiedbyanECGI.Widelyusedlocationbasedapplications(e.g.mappingandnavigationapps)relyonaglobaldatabaseofECGIheldbyathirdparty.ThroughtheuseoftheOMASUPLprotocolandthisdatabase,theECGIistranslatedtoareferencelocation(e.g.towerlatitudeandlongitude),withoutoperatorknowledgeorintervention.
• FailuretomeetE911Mandates.GPSlocationisusuallyusedindispatchingE911calls,andhastimingandaccuracyrequirementsimposedbytheFCC.FailuretoachievetheserequirementsonaregularbasisbecauseofduplicateECGIinformationcouldconstituteaviolationofFCCrulesforoperatorsthatarewithintheE911mandates.
• BillingandAccountingProblems.ECGIsarenormallyprovidedinbillinginformationrecordsproducedbytheAAA.Whileitwillprobablynotcausebillingtothewrongcarrier,itcouldcauseconfusionoverthelocationofthecallwhentherecordsarebeingexaminedforvariouspurposes,includinglegal.
• DifficultyIdentifyingInterference.ECGIsmaybeusedtoidentifyanoperatorwhentryingtolocatethesourceofaninterferingsignal.AnECGIthatisduplicatedwillmakethismoredifficult.
• RFMeasurementExchangeDifficulties.TheuseofuniqueECGIscouldfacilitateexchangeofmeasurementinformationbetweenCBRSAlliancesystems.
3.5. Globally Unique MME Identity (GUMMEI) [7]
TheMMEIdentity(MMEI),inconjunctionwiththeSharedHNI(MCC+MNC),uniquelyidentifiesaMobilityManagementEntity.Lackofuniquenesscouldpreventoperatorsfrom
MCC(3d) MNC(3d) MacroeNBID(20b)
SHNI(6d/24b)
8b
CellIden<ty(28b)
ECGI
Copyright©2018CBRSAlliance|AllRightsReserved 7
supportingroamingoftheiruserstootherSHNINetworks,asinformationrelatedtoroamingdevicescouldnotberoutedtotheappropriateMME.SpecialroutingequipmentknownasaDiameterSignalingController(DSC)couldbeneededtoreceiveDiametermessagescontainingtheIMSIoftheUE(e.g.anattempttovalidatetheUEbyaroamingpartner)andusetheIBNwithintheIMSItodeterminethenetwork,andthentheassociatedMMEGI.
MMEGroupIDuniquenessisrequiredifmultipleMMEsareusingthesharedHNI.
3.6. Participating Service Provider (PSP-ID)
IfNeutralHostNetwork(NHN)servicesareprovided,thesystemmustbroadcastalistof24-bitPSP-IDstoidentifyoperatorswhosesubscribersareallowedtoaccessserviceontheSHNINetwork.PSP-IDscomeinfourtypes,thatoriginatefromdifferentassignmentprocesses:
1. HNI(PLMN-ID).6decimaldigits(24bits)formedastheBCDdigitsofMCC+MNC(HNI).2. 24-bitOID.OnetypeofOIDknownasOUIis24bitsinlength.See:http://standards-
oui.ieee.org/bopid/opid.txt3. OtherOID.AnOIDlongerthan24bitsisusedtocreatea24-bitPSP-IDusingtheSHA-
256hashingalgorithm.4. Domainname.Thedomainnameisusedtocreatea24-bitPSP-IDusingtheSHA-256
hashingalgorithm.
TheCBRSsystemalsosupportsthreedifferentvaluesof‘bssid’toindicatethetypeofPSP-ID:
• 03:ff:ff:ff:ff:ffindicatestype1(HNI).• 03:ff:ff:ff:ff:feindicatestype2(24bitOID).• 03:ff:ff:ff:ff:fdindicatestype3or4(longeridentifierhashedto24bits).
Type1PSP-IDswillbeuniqueiftheHNIisunique,butwouldnotbeuniqueif,forexample,thePSPwasanotherCBRSoperatorusingtheCBRSHNI.
Type2OIDPSP-IDswillalsobeuniqueaslongasaunique24bitidentifierisobtainedfromIEEE.Types3and4(24bithash)willnotbeguaranteedtobeunique.
Anon-uniquePSP-IDcouldresultinadeviceattemptingtoaccessanetworkandbeingrejected.Thiscouldresultinperiodoftime(e.g.severalminutes)duringwhichtheUEmightnotattempttoaccessothersystemsforwhichitisauthorized(seesection5.3.7MF1of[9]).
12
MCC(3d) MNC(3d) MMEGI(16b) MMEC(8b)
MMEI(24b)SHNI(6d/24b)
GUMMEI(48b)
Copyright©2018CBRSAlliance|AllRightsReserved 8
3.7. Tracking Area Identity (TAI) [7] TheTrackingAreaIdentity(TAI)isusedtocoordinatebetweenneighboringCBRSLTEsystems.WhenusingaSharedHNI,operatorsneedtocoordinatetheTAI.TheTAIiscomposedoftheHNIplusa16-bitTAC(TrackingAreaCode).IfaUEisrejectedwhenpresentingaTAItothenetwork,theUEmightnotattempttoaccessanynetworkbroadcastingthatTAIforaperiodoftime(e.g.severalminutes;seesection5.3.7MF1of[9]).Therefore,itisimportantthatTACcodes(theonlyuniquepartoftheTAIwithinaSharedHNI,i.e.SHNI)arecoordinated.Insituationswherecoordinationisnecessary,itcanbedonebyneighboringCBRSoperators.NocoordinationwithMNOsisnecessary,becausetheyuseaTAIbasedontheirowndistinctHNI(notSHNI).
TheTrackingAreaCodeisassignedbytheoperator,notbytheCBRSAlliance,andneedstobelocallyunique(i.e.notusedbyanyothernearbynetworkbroadcastingSHNI).ThefullTAIformatisSHNI(6d/24b)+TAC(16b).TheCBRSAlliancerecommendsthefollowingmethodtodefine6TACcodesthatwillproduceTAIcodesthatwillnotconflictwithanyotherSHNINetworkusingthesamemethod:
1. ThefirstTACisthe16bitbinarycodeforthenumericvalueofthenetwork’sassignedIBN.3
2. Thiscodeplus10,000.3. Thiscodeplus20,000.4. Thiscodeplus30,000.5. Thiscodeplus40,000.6. Thiscodeplus50,000.
4. Deployment Considerations 4.1. Systems Not Needing Uniqueness
ItmaybethatsomeCBRSLTEsystemswillnotneedidentifieruniquenessbecausewheninstalledtheymayhavemostorallofthefollowingcharacteristics:
• TheonlyCBRSsysteminageographicalarea.• Donotacceptincomingcalls.• DonotprovideroamingorNeutralHostNetworkservices.
3 NotethattheIBNisusuallyencodedasBCD,inwhichcase9999wouldbebinary1001100110011001.However,theTACshouldbeencodedasabinaryinteger,so9999wouldbebinary0010011100001111.
16
MCC(3d) MNC(3d)
SHNI(6d/24b)
TAI–TrackingAreaIden=ty(40b)
TrackingAreaCode(TAC–16b)
Copyright©2018CBRSAlliance|AllRightsReserved 9
• Donotallowoutboundroamingbytheirownsubscribers.• ArenotrequiredtoprovideE911service.• Donotsupportthirdpartylocation-enabledapplications.• Havenootherneedforuniqueidentifiers.
However,thesecharacteristicsmaywellchangeovertime,andintheworstcase,couldrequirelaterrenumberingofthenetwork,thereplacementofeverySIMcard,communicationandcoordinationwiththirdpartynetworkelementsforroamingandcharging,changingtheidentificationofeverycell,andsoon.Also,devicesfromanetworkwithnon-uniqueidentifierscouldattempttoregisteronanothernetworkwiththesameCBRS-NID(notrealizingitisroaming),failregistration,thenbeunusableforaperiodoftimeevenbackonthehomenetwork.Similarly,thesenetworkswithnon-uniqueidentifierscouldimpactdevicesfromothernetworks.Thesmalleffortofensuringidentifieruniquenessmightnotprovideanimmediatebenefit,butcouldpreventamuchlargereffortinthefuture.
4.2. Problems with Self-Assigned Identifiers
Someproblemswithsettingasideaself-assignedblockofidentifiersare:
• OperatorsmayhavenochoicebuttoassignuniqueIMSIandCBRS-NIDcodes,inwhichcaseself-assigningMMEGroupIDsandECGIsarelikelyunnecessaryif,forexample,theCBRSAllianceautomaticallyassignsablockofMMEGroupIDsandECGIswitheveryNetworkID.
• Operatorsthatdonotwanttocoordinatecannotbereliedupontoproperlyconfiguretheiridentifiersintheself-assignedaddressspace,andmaystillconflictwithlegitimatelyassignedidentifiers.
• Eveniftheself-assignedaddressspacesarelarge,conflictsmaybemorelikelythanexpected(e.g.ifmultiplecarriersassignECGIsinsequencestartingwithzero).
• LossofaportionoftheaddressspaceforCBRSAAdministration(50%ifthefirstbitisusedtodistinguishedbetweenmanagedandself-assignedaddresses).
4.3. Identity Administrators
ResponsibilityforadministeringidentifiersimportanttoCBRSAlliancemembersissharedbetweentheUSIMSIAdministratorandtheCBRSAlliance,asshowninthetablebelow.
ThisdoesnotconsideroperatorswhodonotuseCBRSAlliancecoordinationservices.
ForidentifiersthatareallocatedbytheIMSIAdministrator(IBNandSharedHNI)theCBRSAlliancedatabasemaystillneedtostorethisinformation,atleastforsomeoperators.
Identifier AssignedbyIMSIAdministrator
AssignedbyCBRSA
AssignedbyCBRSoperator
Identifies Quantity
IMSI MCC+MNC(SHNI)+IBN
n/a UIN Subscription 10,000IBNx100,000UINperSHNI
CBRS-NID ––– CBRS-NID ––– Network 227
Copyright©2018CBRSAlliance|AllRightsReserved 10
GUMMEI SHNI MMEGI MMEC MME 216MMEGIx28MMECperSHNI
ECGI SHNI MacroeNBID
CellIdentity Cellorsector 220ECGIx28CellIdentityperSHNI
TAI/TAC ––– ––– TAC Network(locally)
65534perregionofoverlap
4.4. Business Process
IfanoperatorofoneormoreSHNINetworksneedsIMSIcodes(i.e.willhaveUEshomedontheSHNINetwork)itcanobtainoneormoreIBNs(IMSIBlockNumbers)fromtheUSIMSIAdministrator[1].OneIBNcanbeusedforanynumberofnetworkscontrolledbythesameaccount(e.g.CBRSoperator).TheseIMSIcodeswillbeallocatedfromaSharedHNIdesignatedbytheIMSIAdministratorforthispurpose.
ItisbeneficialtoallindustryparticipantsthatCBRS-NID,MMEGIandECGIareobtainedfromtheCBRSAlliance.AnyorganizationwishingtobeassignedidentifiersforusewithanSHNINetworkmustfirstestablishanaccountalongwithalistofcontactpersonnelwhoareauthorizedtoobtainidentifiersonbehalfoftheorganization.OneaccountcanbeusedtoestablishanynumberofSHNINetworks.
ToobtainanassignmentoftheidentifiersneededforasingleSHNINetworktheaccountholderwillhavetorequestanassignmentofthefollowingfromtheCBRSAllianceforeachnetwork:
• AsingleCBRS-NID.ThisnumberwillbebroadcastintheCSG-IDfieldofSIB1[7]touniquelyidentifytheSHNINetwork(astheSharedHNIthatisalsobroadcastisnotsufficienttoidentifythenetwork).
• OneMMEGroupID.SinceoneMMEGroupIDcanbeusedtocreate256uniqueGUMMEIitisunlikelythatmorethanonewillbeneededbyanSHNINetworkbutifneeded,morethanonecanbeallocatedtoanetwork.
• OneormoreMacroeNBIDs.ThesizeandconfigurationofthenetworkwilldictatethequantityofMacroeNBIDsrequired.
• OneormoreIBNs.AssignedbytheUSIMSIAdministrator,butmaybevoluntarilystoredintheCBRSAdatabase,alongwiththeCBRSAassignedidentifierstofacilitateroaming.
4.5. Identifier Management Principles
CBRSAlliancewillcarefullymanagetheidentifierstoensurethatthelimitedsupplylastsformanyyearsbasedonthefollowingprinciples:
• VerifythatanewaccountisaCBRSoperator.• Verifythatthequantityofnumberingresourcesrequestedisreasonable.
Copyright©2018CBRSAlliance|AllRightsReserved 11
• KeepincontactwiththeCBRSoperatortoregularlyverifythattheassignedcodesareinuse.
• Reclaimcodesthatarenolongerneeded.• EducatetheCBRSindustryontheneedforidentifiercoordination.• DocumenttheassignmentsofSHNIandIBNcodesprovidedtotheCBRSAlliance.• CoordinatetheassignmentandmanagementofNID,ECGIandMMEGIcodes.• MonitorIBNassignmentswithinCBRSSharedHNI(s)andcoordinateasneeded.
4.6. Process Implementation
AssignedidentifierswillbestoredinadatabasewithawebinterfaceforCBRSAllianceidentifierassignments.Therelationshipsbetweentheelementsofthissystemareshownbelow.
Onceanaccounthasbeenapproved,anyoftheapprovedcontactsfortheaccountcanobtainassignmentsofthethreetypesofidentifiersmanagedbytheCBRSAlliance.Thesystemwillalsoallowaccountstoreviewtheircurrentassignmentsofcodes,andwillgenerateanannualinvoiceforallassignedcodes.
NotethattheIMSIBlockNumbers(IBN)willbeassignedbytheUSIMSIAdministrator(IMSI-A).Onthatbasis,adatabaseofIBNmaynotbeneededtobemaintainedbytheCBRSA.However,iftheIMSI-Adoesnotprovideaneasilyqueriedandcurrentlist,orifreal-timequeriesareneeded,thismayneedtobemaintainedbytheCBRSA(directlyorviaanauthorizeddatabaseprovider).
Contact• Loginname• Userid
IMSIBlock• IBN
Network• CBRS-NID
MMEGroup• MMEGI
Cell/eNodeB• ECGI
Account• CBRSacct#
SharedHNI• MCC+MNC
MMECode
Cellnumber
IdenGfierandotherObjectRelaGonships
CBSD
Administrator
IMSI-A
CBRSA
Operator
Copyright©2018CBRSAlliance|AllRightsReserved 12
Similarly,theSharedHNIisassignedbytheIMSI-A.However,toallowthepossibilityofmultipleSharedHNIassignmentsinthefuture,atablecouldbemaintainedbyCBRSA,althoughatfirstthetablewillhaveonlyoneentry.
Copyright©2018CBRSAlliance|AllRightsReserved 13
Annex A. ECGI Uniqueness and E911 Detailed Rationale
GeographicallocationisanimportantcomponentofEmergencyCalling(E911inNorthAmerica)thatprovidestwobasiclocation-relatedfunctions:
• IdentifyingtheappropriatePublicSafetyAnsweringPoint(PSAP)toreceivethecall(e.g.town,city,county,highwaypatrol).
• Identifyingtheaccuratelocationfordispatchofpublicsafetyassistance(ambulance,policecar,etc).
Geographicallocationcanmostrapidlybeprovidedbyusingtheservingcelllocation(e.g.towerlatitude,longitudeandperhapsaltitude),butthismaybeinaccuratebyseveralmilesinamacrocell.GPSlocationismuchmoreaccurate(severalmeters)buttakeslongertoobtain.Therefore,giventhatUSFCCE911mandatesrequirebothspeedandaccuracy,thePSAPisgenerallyidentifiedusingcelllocation(forspeed)anddispatchofanemergencyvehicletypicallyusesGPSlocationmethods(foraccuracy,sincedispatchisusuallyinitiatedseveralsecondsorevenminutesafterthecallisconnectedtothePSAP).
VariousspecificationsindicatethatattimestheCellID(ECGI)isusedtodeterminethelocationofamobile,anddependingonthenetworkarchitecture,thismayrequiretheECGItobegloballyunique:
• 3GPPTS23.167indicatesthat,inscenarioswheretheIMScoreneedstoretrievethelocationinformation,theCellID(ECGI)isincludedintheSIPinvitesenttotheemergencycallansweringcenter(PSAP).
• 3GPPTS23.167alsostatesthat,“Locationisindicatedinnetworkterms,forexampleusingtheglobalcellid[ECGI]incellularnetworks…”.
• ATIS-0700015.v003statesthatthelocationforIMS-basedE911maybebasedontheCellID.IftheLRForLocationServerareoutsidetheCBRSsystemthentheECGIwouldneedtobegloballyunique.
Leveragingnationalcross-referencetablesofECGIandgeographicalcoordinates,andtheydoformacro-cells,ECGIisusedtoderivethecelllocation(e.g.actualtowerlocationorapproximategeographiccenterofthecoveragearea)inLTEsystems.Ifthisconversionisdonewithinanoperator’snetwork,forbothPSAProutinganddispatch,theECGIonlyneedstobelocallyunique.Fromthisapproximatelocation,theEmergencyServiceslocationserverwillobtainatemporaryroutingphonenumber(ESQK)thatcanbeusedtobothroutethecalltothecorrectPSAPandprovideakeyforthePSAPtoobtainthenowstoredapproximatelocationinformation.Itislikelythatthisfunctionwillbeoutsourcedduetotheneedtomaintainapoolofphonenumbersforeveryansweringpoint.TheECGIisalsoimportantforGPSingeneral(notjustE911)becauseitprovidesthereferencelocationtomakeGPSfixesfasterandmoreaccurate.ThisrequiresacrossreferencefromECGItotowerlocation,whichrequiresuniquenessoftheECGIifthetableismaintainedbyathirdparty.Itisknownthatindustry-widecrossreferencesaremaintainedbyseveralorganizations,includingGoogle,inordertosupportSUPL-basedlocationservices.TheSUPLprotocol
Copyright©2018CBRSAlliance|AllRightsReserved 14
transmitstheECGIfromthephonetotheserver(e.g.supl.google.com),notthecelllocation.SUPLserversaregenerallymaintainedbyphoneorphoneOSmanufacturers,andnotbyindividualoperators.
Inthecaseofoutsourcedlocationfunctions,agloballyuniqueECGIwillprobablybenecessarybecausetheremaynotbeadditionalinformationtobeabletoresolvetheECGIandlocation.
Copyright©2018CBRSAlliance|AllRightsReserved 15
Annex B. Revision History
Version Date Description V1.0.0 2018-11-27 Release 1 of this Report