SHARINGOFSPECTRUMUSEDBYSATELLITESYSTEMS

HOWSATELLITESYSTEMSSHARESPECTRUMAMONGTHEMSELVES,ANDWITHTERRESTRIALSYSTEMS

July 20, 2015

Jose AlbuquerqueChief, Satellite Division

FCC

May 17, 2017

SharingScenariosu SharingBetweenGSOFSSSatelliteNetworks(DirectionalEarth

StationAntennas)

u SharingBetweenNGSOFSSSatelliteSystems(DirectionalEarthStationAntennas)

u SharingBetweenGSOorNGSOSatelliteSystems(Non-DirectionalAntennas)

u Co-FrequencyOperationofGSOandNGSOFSSSatelliteSystems(DirectionalEarthStationAntennas)

u SharingBetweenSatelliteSystems(Earth-to-Space)andTerrestrialSystems

u SharingBetweenSatelliteSystems(Space-to-Earth)andTerrestrialSystems

GeostationaryOrbit(GSO)SatellitesCommunicatingwithDirectionalEarthStationAntennas

u ApplicabletomostGSOfixed-satelliteservice(FSS)satellites

u Spacestationsareauthorizedona“first-come-first-served”basisandhavetoaccommodatelatecomersthatareatleasttwodegreesapartinthegeostationaryorbit

u The“two-degreepolicy”,adoptedin1983andrefinedin2015,strikesabalancebetweenmaintainingflexibilitytoearlycomersandmaximizingopportunitiestolatecomers

u Compatibilityofsatellitenetworkswithspacestationsseparatedbytwodegreesisensuredbylimitingradiationfromearthstationstowardadjacentsatellitesanddownlinke.i.r.p.densityorpower-fluxdensitygeneratedbyspacestations

u Limitscanbeexceededifcoordinatedwithneighboringspacestations

FCCTwo-DegreePolicyversusITUFramework

u Therehasbeenalotofdiscussionbetweenthetworegulatoryregimes,includinginthecommentsandreplycommentsprecedingtheDecember2015Part25Order

u TheITUframeworkisgenerallybasedona“first-come-first-served”principle,butdiffersfromtheFCCtwo-degreeapproachinsomekeypoints,e.g.u Alate-comingITUfilingisacceptedevenifincompatiblewithanearlier

filing;anFCCapplicationthatis“incompatible”withalicenseisdismissedunlesstheincompatibilityhasbeeneliminatedthroughcoordination

u IntheITU,anearlierfilerisexpectedto“accommodate”alatecomer,butthereisnodefinitionofhowmuchaccommodationisrequired;theFCCrulesalsoallowcoordinationbetweentheparties,but,intheabsenceofanagreement,emissionlimitsassociatedwiththetwo-degreepolicyclearlydefinetherightsandobligationsoftheearlycomer

Non-GeostationaryOrbit(NGSO)SatellitesCommunicatingwithDirectionalEarthStationAntennas

u ApplicabletosomeNGSOfixed-satelliteservice(FSS)satellites

u Anapplicationthatcomportswithexistingrulesandiscompatiblewithpreviousauthorizationsandapplicationswillbeputonpublicnoticeandtriggersa“processinground”(applicationscompetingfortheuseofthesamefrequenciescanbesubmitteduntilaspecificdate)

u Allapplicationsthatmeetallrequirementsintherulesaregrantedforalltherequestedspectrum

u Iftwoormorespacestationsofdifferentsystemsarealignedwithanearthstationofoneofthesesystems(orwithinacertainangle,asmeasuredfromtheearthstation),an“in-lineevent”occursandthereispotentialforinterferencebetweenthesystemsinvolved

u Duringin-lineevents,useoftheoverlappingportionsofthespectrumassignedtothesystemsinvolvedhastobecoordinatedbytheparties;intheabsenceofacoordinationagreementtheoverlappingspectrumisdividedequallyamongthepartiesinvolved

FCCversusITUFramework

u TheITUframeworkisagainbasedona“first-come-first-served”principleandtheearlierfilerisexpectedtoaccommodatealatecomer,withoutadefinitionofhowmuchaccommodationisrequired

u TheFCCprocessingroundapproachplacesseveralapplicantsonequalgroundsandmandatesanequalsplitoftheoverlappingspectrumintheabsenceofacoordinationagreementthataddressestheperiodsoftimewhenthereisapotentialforinterference(thiscontrastswiththelackofdefinedoperatingparametersasafallbackintheITUenvironmentwhenthereisnoagreementbetweentheparties)

u OnechallengeintheFCCapproachishowtodealwithapplicationsthatmaycomeinthefuture,afteraprocessingroundhasalreadybeenconductedu Theseapplicationshavetobeconsideredonacase-by-casebasisandoptionsrange

from,ononeextreme,requiringthenewsystemtoprotectallpreviouslyfiledsystemsto,ontheotherextreme,givingthenewsystemthesametreatmentgiventothepreviouslyfiledsystems

NGSOorGSOSatellitesCommunicatingwithNon-DirectionalEarthStationAntennas

u Inthisscenariotherulesprescribeaprocessingroundand,iftheavailablespectrumisnotenoughtomeettherequestsofallapplicationsthatcomportwithexistingrulesandarecompatiblewithpreviousauthorizations,spectrumisequallydividedamongtheapplicants(bandsegmentation)

u AlthoughthecurrentBigLeolicensees(IridiumandGlobalstar)wereauthorizedbeforetheadoptionofthe“modifiedprocessinground”regimein2003,sharinghasbeenachievedthroughbandsegmentation(exceptfor0.95MHzthataresharedbetweenthetwolicensees)

Co-FrequencyOperationofNGSOandGSOFSSSatellitesCommunicating

withDirectionalEarthStationAntennas

u IntheITUframeworkNGSOsystemscannotcauseunacceptableinterferencetoorclaimprotectionfromGSOsatellitenetworks

u IncertainportionsofC-band,Ku-bandandKa-band,theITUhasdevelopedequivalentpowerflux-density(epfd)limitsthat,ifmetbyaNGSOFSSsystem,ensurethatthissystemhasfulfilledtherequirementsofnotcausingunacceptableinterferencetoGSOFSSsatellitenetworksu epfd↓applicabletoNGSOFSSsatelliteemissionsensuretheprotectionofGSOFSS

earthstations

u epfd↑applicabletoemissionsfromearthstationsofaNGSOFSSsystemensuretheprotectionofGSOFSSsatellites

u IntheFCCrulesthereisnowidelyapplicableobligationimposedonNGSOsystems,butthesameepfdlimitsdevelopedbytheITUforportionsKu-bandhavebeenincorporatedintherules(epfdlimitsapplicabletoC-bandandKa-bandfrequenciesarenotintheFCCrulesbuthavebeenusedinFCCgrantsonanadhocbasis)

ExceptionfortheRequirementofNGSOFSSSystemsHavingtoProtect

GSOFSSNetworksu IntheITUframeworkNGSOFSSsystemsandGSOFSSnetworkshave

equalstatusinthefrequencybands18.8-19.3GHz(↓)and28.6-29.1GHz(↑)

u InthesefrequencybandstheITU“first-come-first-served”principleappliesand,asinthecaseofGSOsatellitenetworks,theearlycomerhastoaccommodatethelatecomer,withnocleardefinitionofthelevelofaccommodationrequired

u IntheFCCrules,thefrequencybands18.8-19.3GHz(↓)and28.6-29.1GHz(↑)aredesignatedforNGSOFSSuseu GSOFSSoperationintheband28.6-29.1GHzcanonlybeauthorizedona

secondarybasis

u GSOFSSoperationintheband18.8-19.3GHzcanonlybeauthorizedonanon-interference-non-protectedbasisthroughawaiveroftheU.S.TableofFrequencyAllocations

SharingBetweenSatelliteSystemsandTerrestrialSystems(FS&MS):

SpectrumAllocatedtoEarth-to-SpaceTransmissions(1)u Interferenceisfromterrestrialstationstosatellitereceivers

u Thisinterferencemechanismhasbeentraditionallyaddressedbylimitinge.i.r.p.,requiringdirectionalantennas,andimposingconstraintsonpointingintendedtoprotectGSOsatellites

u Inmostsituations,thisinterferencemechanismhasnotbeenaconcernbecauseaggregateinterferenceisnotsignificant

u Aggregationbecomesaconcernwhenthereispotentialformassiveterrestrialdeployment

u Somehistoricexamplesare:ITUResolutiononWASandRLANsin5GHz;extensivediscussionsarounddeploymentofUWBsystemsintheU.S.

u Morerecently,concernsreappearedinconnectionwith5Gterrestrialdeployment(e.g.discussionsrelatedto5Gmobileservicein27.5-28.35GHz)

u Controllingaggregateinterferencethroughe.i.r.p.limitationsonindividualterrestrialstationsischallenging(undulylimitingdeploymentvs.notprotectingsatellitereceivers)

u Settingalimitforaggregateinterferencebringsthechallengeofenforcingthislimit

SharingBetweenSatelliteSystemsandTerrestrialSystems(FS&MS):

SpectrumAllocatedtoEarth-to-SpaceTransmissions(2)u Interferenceisfromsatelliteearthstationstoterrestrialstationreceivers

u Ifearthstationsandterrestrialstationshaveequalstatusandareindividuallyauthorized,afirst-come-first-servedregimeisappropriateandlatecomershavetoshowcompatibilitywithearlycomersthroughcoordinationtriggeredwhenpre-determinedinterferencethresholdsareexceeded(e.g.5,925-6,425MHz)

u Ifearthstationsorterrestrialstationscanbedeployedanywhere(blanketlicensedearthstationsorterrestrialstationsauthorizedinagivengeographicarea),thetwotypesofstationscannothavethesamestatus

u Ifterrestrialstationshaveahigherstatus,earthstationscanbedeployed:

u withasecondarystatusandmayhavetoceaseoperationsinordertoprotectfutureterrestrialdeployments(concernswithwidespreaddeploymentandpotentialdifficultiesinstoppingtransmissionsfromexistingusersofthesatelliteservice);or

u inawaythatwillprecludeterrestrialdeploymentinverylimitedareas

u Ifearthstationshaveahigherstatus,terrestrialstationsmightbedeployedonanopportunisticbasis(concernswithwidespreaddeploymentandpotentialdifficultiesindealingwithinterferencetoexistingusersoftheterrestrialservice)

SharingBetweenSatelliteSystemsandTerrestrialSystems(FS&MS):

SpectrumAllocatedtoSpaceto-EarthTransmissions(1)

u Interferencefromterrestrialstationstoearthstationreceivers

u Ifearthstationsandterrestrialstationshaveequalstatusandareindividuallyauthorized,afirst-come-first-servedregimeisappropriateandlatecomershavetoshowcompatibilitywithearlycomersthroughcoordinationtriggeredwhenpre-determinedinterferencethresholdsareexceeded(e.g.3,700-4,200MHz)

u Ifearthstationsorterrestrialstationscanbedeployedanywhere(blanketlicensedearthstationsorterrestrialstationsauthorizedinagivengeographicarea),thetwotypesofstationscannothavethesamestatus

u Ifterrestrialstationshaveahigherstatus,earthstationscanbedeployed:u withasecondarystatusandhavetooperateonanon-protectedbasis(concernswithwidespreaddeployment

andpotentialdifficultiesindealingwithinterferencetoexistingusersofthesatelliteservice);or

u inawaythatwillprecludeterrestrialdeploymentinverylimitedareas

u Ifearthstationshaveahigherstatus,terrestrialstationsmightbedeployedwithasecondarystatusandmayhavetoceaseoperationsinordertoprotectfutureearthstations(concernswithwidespreaddeploymentandpotentialdifficultiesinstoppingtransmissionsfromexistingusersoftheterrestrialservice)

SharingBetweenSatelliteSystemsandTerrestrialSystems(FS&MS):

SpectrumAllocatedtoSpaceto-EarthTransmissions(2)u Interferencefromsatellitetransmitterstoterrestrialstationsreceivers

u Thisinterferencemechanismhasbeentraditionallyaddressedbysettinglimitstothespectralpowerflux-density(pfd)thatsatellitetransmissionscangenerateonthesurfaceoftheEarth

u WhenapplyingthesepfdlimitstoNGSOconstellations,twoissueshavetobeaddressedu ThepfdgeneratedbyaNGSOconstellationatanygivenpointonthegroundvaries

withtimeandinthiscontextitmightbeappropriatetodefineapfdthatisexceededonlyforacertainpercentageofthetimeratherthanapfdthatcanneverbeexceeded(developinganepfdlimitmayalsobeanoptionbutthiswouldhavetobeassociatedwithacertaincollectionofterrestrialstationantennas)

u ThecurrentFCCandITUrulesestablishpfdlimitsperspacestationwhileforNGSOconstellationstheaggregatepfdshouldbelimited(currentlyonlyinthefrequencyband18.8-19.3GHzthereisacorrectionfactortotakeintoaccountthenumberofsatellitesintheconstellationandeventhiscorrectionfactorisnotappropriateforlargerconstellations)