ETSI EN 301 790 V1.2.2 (2000-12)

Digital Video Broadcasting (DVB); Interaction channel for satellite distribution systems

DEN/JTC-DVB-96

Digitalna videoradiodifuzija (DVB) – Povratni kanal za satelitske distribucijske sisteme

General Information

• Status: Published
• Publication Date: 30-Nov-2000
• Technical Committee: BROADCAS - EBU/CENELEC/ETSI on Broadcasting
• Current Stage: 12 - Completion
• Due Date: 01-Dec-2000
• Completion Date: 01-Dec-2000
• Ref Project: SIST EN 301 790 V1.2.2:2003 - Digital Video Broadcasting (DVB); Interaction channel for satellite distribution systems

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digitalna videoradiodifuzija (DVB) – Povratni kanal za satelitske distribucijske sistemeDigital Video Broadcasting (DVB); Interaction channel for satellite distribution systems33.170Televizijska in radijska difuzijaTelevision and radio broadcasting33.070.40SatelitSatelliteICS:Ta slovenski standard je istoveten z:EN 301 790 Version 1.2.2SIST EN 301 790 V1.2.2:2003en01-december-2003SIST EN 301 790 V1.2.2:2003SLOVENSKI
STANDARD
ETSIEN301790V1.2.2(2000-12)EuropeanStandard(Telecommunicationsseries)DigitalVideoBroadcasting(DVB);Interactionchannelforsatellitedistributionsystems;EuropeanBroadcastingUnionUnionEuropéennedeRadio-TélévisionEBU·UERSIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)2ReferenceDEN/JTC-DVB-96Keywordsbroadcasting,DVB,interaction,satelliteETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88ImportantnoticeIndividualcopiesofthepresentdocumentcanbedownloadedfrom:http://www.etsi.orgThepresentdocumentmaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthepresentdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/Ifyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]opartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2000.©EuropeanBroadcastingUnion2000.Allrightsreserved.SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)3ContentsIntellectualPropertyRights.7Foreword.71Scope.82References.83Definitions,symbolsandabbreviations.93.1Definitions.93.2Symbols.93.3Abbreviations.94ReferenceModelsforSatelliteInteractiveNetworksinDVB.114.1ProtocolStackModel.114.2SystemModel.124.3ReferenceModeloftheSatelliteInteractiveNetwork.135ForwardLink.146ReturnLinkBase-bandPhysicalLayerSpecificationandMultipleAccessDefinition.146.1RCSTsynchronization.156.1.1TimingControl.156.1.2Carriersynchronization.156.1.3Burstsynchronization.156.1.4Symbolclocksynchronization.166.2BurstFormat.166.2.1Traffic(TRF)burstformats.166.2.1.1ATMTRFburst.166.2.1.2OptionalMPEG2-TSTRFburst.166.2.2Synchronizationandacquisitionburstformats.176.2.2.1Synchronization(SYNC)burstformat.176.2.2.2Acquisition(ACQ)burst.176.2.3CommonSignallingChannel(CSC)burstformat.186.2.4BitNumberingandInterpretation.196.2.5TransmissionOrder.196.3Randomizationforenergydispersal.196.4Coding.206.4.1CRCerrordetectioncode.206.4.2ReedSolomonoutercoding.206.4.3Convolutionalinnercoding.206.4.4Turbocode.216.4.4.1Descriptionoftheturbocodepermutation.226.4.4.2Determinationofthecirculationstates.236.4.4.3Ratesandpuncturingmap.236.4.4.4OrderoftransmissionandmappingtoQPSKconstellation.246.5Modulation.256.5.1BitmappingtoQPSKconstellation.256.5.2Basebandshapingandquadraturemodulation.256.5.3Outputpowercontrol.266.5.4GuardTime.266.6MACmessages.266.6.1PrefixMethod.266.6.1.1Prefixmethodmechanism.266.6.1.2SatelliteAccessControl(SAC)field.266.6.2Dataunitlabellingmethod(DULM).276.6.2.1DULMwithATM-formatting.276.6.2.2DULMwithMPEG-formatting.296.6.3Mini-slotMethod.306.6.4ContentionbasedMini-slotMethod.30SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)46.7MultipleAccess.306.7.1MF-TDMA.306.7.1.1FixedMF-TDMA.306.7.1.2DynamicMF-TDMA(Optional).316.7.1.3Frequencyrange.316.7.2Segmentationofthereturnlinkcapacity.326.7.2.1Superframes.326.7.2.2Frames.336.7.2.3Timeslots.336.8Capacityrequestcategories.346.8.1ContinuousRateAssignment(CRA).346.8.2RateBasedDynamicCapacity(RBDC).346.8.3VolumeBasedDynamicCapacity(VBDC).346.8.4AbsoluteVolumeBasedDynamicCapacity(AVBDC).346.8.5FreeCapacityAssignment(FCA).347Synchronizationprocedures.357.1OverallEventsSequencing.357.2Initialsynchronizationprocedure.377.3Logonprocedure.387.4Coarsesynchronizationprocedure(Optional).387.5FineSynchronizationProcedure(Optional).397.6SynchronizationMaintenanceprocedure.407.7LogoffProcedure.417.7.1General.417.7.2Normal.417.7.3Abnormal.418Controlandmanagement.418.1Protocolstack.418.1.1RCSTTypeA(IP).418.1.2OptionalRCSTTypeB(NativeATM).438.2RCSTAddressing.448.3ForwardLinkSignalling.448.3.1GeneralSITables.448.3.1.1SuperframeCompositionTable(SCT).448.3.1.2FrameCompositionTable(FCT).448.3.1.3Time-SlotCompositionTable(TCT).458.3.1.4SatellitePositionTable(SPT).458.3.1.5CorrectionMessageTable(CMT).458.3.1.6TerminalBurstTimePlan(TBTP).458.3.2TerminalInformationMessage(TIM).458.3.3PCRInsertionTSPacket.458.3.4Summary.458.3.5RepetitionRates.468.4ReturnLinkSignalling.468.4.1RCSTsynchronizationandIdentificationmessages.468.4.2ConfigurationparametersbetweenRCSTandNCC(optional).478.4.3OtherMessagesforNetworkManagement(optional).478.4.4BurstTimePlanExchange.488.5CodingofSIforForwardLinkSignalling.488.5.1Introduction.488.5.2SITableMechanism.488.5.3DSM-CCSectionMechanism.488.5.4CodingofPIDandtable_idfields.498.5.5Tabledefinitions.498.5.5.1StandardSectionHeaders.498.5.5.1.1SISectionHeader.508.5.5.1.2DSM-CCPrivateSectionHeader.518.5.5.2SuperframeCompositionTable(SCT).528.5.5.3FrameCompositionTable(FCT).548.5.5.4TimeslotCompositionTable(TCT).55SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)58.5.5.5SatellitePositionTable(SPT).588.5.5.6PCRInsertionTransportStreampacket.588.5.5.6.1TSpacketformat.588.5.5.6.2Adaptationfield.598.5.5.6.3OptionalPayloadfield.598.5.5.7TerminalBurstTimePlan(TBTP).608.5.5.8TerminalInformationMessage(TIM).628.5.5.9CorrectionMessageTable(CMT).648.5.5.10Descriptorcoding.668.5.5.10.1DescriptorIdentificationandlocation.668.5.5.10.2NetworkLayerInfoDescriptor(optional).668.5.5.10.3CorrectionMessagedescriptor.678.5.5.10.4LogonInitializeDescriptor.688.5.5.10.5ACQAssignDescriptor.708.5.5.10.6SYNCAssignDescriptor.718.5.5.10.7EncryptedLogonIDDescriptor.728.5.5.10.8EchoValueDescriptor.728.5.5.10.9Linkagedescriptor(privatedata).738.5.5.10.10RCScontentdescriptor.748.5.5.10.11Satelliteforwardlinkdescriptor.758.5.5.10.12Satellitereturnlinkdescriptor.778.5.5.10.13TableUpdateDescriptor.788.5.5.10.14Contentioncontroldescriptor.798.5.5.10.15CorrectionControldescriptor.798.5.5.11Accessingoftheforwardlinksignalling.809Security,Identity,Encryption.849.1Authentication.849.2ForwardLink.849.3ReturnLink.859.4Security(optional).859.4.1Cryptographicprimitives.859.4.1.1Publickeyexchange.869.4.1.2Hashing.869.4.1.3Encryption.869.4.1.4Pseudo-randomnumbers.879.4.2MainKeyExchange,MKE.879.4.3QuickKeyExchange,QKE.889.4.4ExplicitKeyExchange,EKE.889.4.5Keyderivation.889.4.6Datastreamprocessing.889.4.6.1Payloadstreams.899.4.6.2Dataencryption.899.4.6.3Encryptionflags.899.4.6.4Chainingandinitializationvector.909.4.7SecurityEstablishment.909.4.8Persistentstatevariables.919.4.8.1Guaranteeddelivery.919.4.9SecurityMACMessages.919.4.9.1SecuritySign-On.919.4.9.2SecuritySign-OnResponse.929.4.9.3MainKeyExchange.939.4.9.4MainKeyExchangeResponse.939.4.9.5QuickKeyExchange.949.4.9.6QuickKeyExchangeResponse.949.4.9.7ExplicitKeyExchange.959.4.9.8ExplicitKeyExchangeResponse.959.4.9.9Wait.96SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)6AnnexA(informative):Compliancetable.97Bibliography.98History.99SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)7IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinETSISR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinETSISR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyJointTechnicalCommittee(JTC)oftheEuropeanBroadcastingUnion(EBU),ComitéEuropéendeNormalisationElectrotechnique(CENELEC)andtheEuropeanTelecommunicationsStandardsInstitute(ETSI).NOTE:TheEBU/ETSIJTCBroadcastwasestablishedin1990toco-ordinatethedraftingofstandardsinthespecificfieldofbroadcastingandrelatedfields.Since1995theJTCBroadcastbecameatripartitebodybyincludingintheMemorandumofUnderstandingalsoCENELEC,whichisresponsibleforthestandardizationofradioandtelevisionreceivers.TheEBUisaprofessionalassociationofbroadcastingorganizationswhoseworkincludestheco-ordinationofitsmembers'activitiesinthetechnical,legal,programme-makingandprogramme-exchangedomains.TheEBUhasactivemembersinabout60countriesintheEuropeanbroadcastingarea;itsheadquartersisinGeneva.EuropeanBroadcastingUnionCH-1218GRANDSACONNEX(Geneva)SwitzerlandTel:[phone]Fax:[phone]FoundedinSeptember1993,theDVBProjectisamarket-ledconsortiumofpublicandprivatesectororganizationsinthetelevisionindustry.ItsaimistoestablishtheframeworkfortheintroductionofMPEG-2baseddigitaltelevisionservices.Nowcomprisingover200organizationsfrommorethan25countriesaroundtheworld,DVBfostersmarket-ledsystems,whichmeettherealneeds,andeconomiccircumstances,oftheconsumerelectronicsandthebroadcastindustry.NationaltranspositiondatesDateofadoptionofthisEN:24November2000DateoflatestannouncementofthisEN(doa):28February2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31August2001DateofwithdrawalofanyconflictingNationalStandard(dow):31August2001SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)81ScopeThepresentdocumentisthebaselinespecificationfortheprovisionoftheinteractionchannelforGEOsatelliteinteractivenetworkswithfixedreturnchannelsatelliteterminals(RCST).ThepresentdocumentfacilitatestheuseofRCSTsforindividualorcollectiveinstallation(e.g.SMATV)inadomesticenvironment.Italsosupportstheconnectionofsuchterminalswithin-housedatanetworks.ThepresentdocumentmaybeappliedtoallfrequencybandsallocatedtoGEOsatelliteservices.ThesolutionsprovidedinthepresentdocumentforinteractionchannelforsatelliteinteractivenetworksareapartofawidersetofalternativestoimplementinteractiveservicesforDigitalVideoBroadcasting(DVB)systems.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.[1]ETSIEN300421:"DigitalVideoBroadcasting(DVB);Framingstructure,channelcodingandmodulationfor11/12GHzsatelliteservices".[2]ETSITR101202:"DigitalVideoBroadcasting(DVB);ImplementationguidelinesforDataBroadcasting".[3]ETSIETS300802:"DigitalVideoBroadcasting(DVB);Network-independentprotocolsforDVBinteractiveservices".[4]ETSIEN300468:"DigitalVideoBroadcasting(DVB);SpecificationforServiceInformation(SI)inDVBsystems".[5]ETSIEN301192:"DigitalVideoBroadcasting(DVB);DVBspecificationfordatabroadcasting".[6]ETSIEN301459:"SatelliteEarthStationsandSystems(SES);HarmonizedENforSatelliteInteractiveTerminals(SIT)andSatelliteUserTerminals(SUT)transmittingtowardssatellitesingeostationaryorbitinthe29,5GHzto30GHzfrequencybandscoveringessentialrequirementsunderarticle3.2oftheR&TTEDirective".[7]IETFRFC1483(1993):"MultiprotocolEncapsulationoverATMAdaptationLayer5".[8]ETSITR100815:"DigitalVideoBroadcasting(DVB);GuidelinesforthehandlingofAsynchronousTransferMode(ATM)signalsinDVBsystems".[9]ISO/IEC13818-1(1996):"Informationtechnology-Genericcodingofmovingpicturesandassociatedaudioinformation;Part1:Systems".[10]ETSIETR154:"DigitalVideoBroadcasting(DVB);ImplementationguidelinesfortheuseofMPEG-2Systems,VideoandAudioinsatellite,cableandterrestrialbroadcastingapplications".[11]ITU-TRecommendationQ.2931(1995):"BroadbandIntegratedServicesDigitalNetwork(B-ISDN)-DigitalSubscriberSignallingSystemNo.2(DSS2)-User-NetworkInterface(UNI)-Layer3specificationforbasiccall/connectioncontrol".SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)9[12]IEEE802.3(1996):"Informationtechnology-Telecommunicationsandinformationexchangebetweensystems-Localandmetropolitanareanetworks-Specificrequirements-Part3:Carriersensemultipleaccesswithcollisiondetection(CSMA/CD)accessmethodandphysicallayerspecifications".[13]ITU-TRecommendationI.432(1999):"B-ISDNuser-networkinterface-Physicallayerspecification".[14]ETSIES200800:"DigitalVideoBroadcasting(DVB);DVBinteractionchannelforCableTVdistributionSystem(CATV);DVBdocumentA023Rev.1,June1999.[15]IETFRFC2104(1997):"HMAC:Keyed-HashingforMessageAuthentication".[16]ANSI/IEEE754(1985):"IEEEStandardforBinaryFloating-PointArithmetic".[17]ISO/IEC13818-6(1998):"Informationtechnology-Genericcodingofmovingpicturesandassociatedaudioinformation-Part6:ExtensionsforDSM-CC".[18]ITU-TRecommendationI.363-5(1996):"B-ISDNATMAdaptationLayerspecification:Type5AAL".3Definitions,symbolsandabbreviations3.1DefinitionsForthepurposesofthepresentdocument,thefollowingtermanddefinitionapplies:reserved:term"reserved",whenusedintheclausesdefiningthecodedbitstream,indicatesthatthevaluemaybeusedforfutureextensions.Unlessotherwisespecifiedwithinthepresentdocument,allreservedbitsshallbesetto'1'.3.2SymbolsForthepurposesofthepresentdocument,thefollowingsymbolsapply:*multiplication^power~concatenationmodmodulodivision(unsignedchar)xANSICcastoperator:convertsvaluextounsignedchar""emptystring(zerolength)nonce1randomstring(NCC)nonce2randomstring(RCST)NatmNumberofATMcellsinanATMTRFburst(1,2or4).NmpegNumberofMPEGpacketsinanoptionalMPEG2-TSTRFburst(1and2*nforn=1to12).Np,atmNumberofbytesoftheprefixusedonATMTRFbursts(0,2or4).Np,syncNumberofbytesoftheoptionalprefixusedonSYNCbursts:0,2…31forconcatenatedcode,0,12or16fortheTurbocode(seesubclause6.4).3.3AbbreviationsForthepurposesofthepresentdocument,thefollowingabbreviationsapply:AALATMAdaptationLayerACQAcquisitionburstATMAsynchronousTransferModeAVBDCAbsoluteVolume-BasedDynamicCapacityBCDBinaryCodedDecimalBTPBurstTimePlanCBCCipherBlockChainingSIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)10CMFControl&MonitoringFunctionsCMTCorrectionMessageTableCRCapacityRequestsCRAConstant-RateAssignmentCRCCyclicRedundancyCheckCRSCCircularRecursiveSystematicConvolutionalCSCCommonSignallingChannelCTRL/MNGMControl/ManagementvirtualchannelusedinDULMDESDataEncryptionStandardDSM-CCDigitalStorageMedium-CommandandControlDULMDataUnitLabellingMethodDVBDigitalVideoBroadcastDVB-SDigitalVideoBroadcastbySatelliteEKEExplicitKeyExchangeENEuropeanNormETSEuropeanTelecommunicationsStandardETSIEuropeanTelecommunicationsStandardsInstituteFCAFreeCapacityAssignmentFCTFrameCompositionTableFLSForwardLinkSignallingGEOGeostationaryEarthOrbitGFCGenericFlowControlHMACHash-basedMessageAuthenticationCodeHPAHighPowerAmplifierIIn-phaseIDIdentifierIDUIndoorunitIEInformationElementIECInternationalElectrotechnicalCommissionIEEEInstituteofElectricalandElectronicsEngineersIFIntermediateFrequencyIPInternetProtocolISDNIntegratedServicesDigitalNetworkISOInternationalStandardsOrganizationITUInternationalTelecommunicationUnionIVInitializationVectorLFSRLinearFeedbackShiftRegisterLLCLogicalLinkControlLSBLeastSignificantBitM&CMonitoringandControlMACMediumAccessControlMF-TDMAMultiple-FrequencyTime-DivisionMultipleAccessMIBManagementInformationBaseMKEMainKeyExchangeMPEGMovingPictureExpertsGroupMSBMostSignificantbitNCCNetworkControlCentreNCRNetworkClockReferenceNITNetworkInformationTableNIUNetworkInterfaceUnitOBOOutputBack-OffODUOutdoorunitOSIOpenSystemsInterconnectionPATProgramAssociationTablePCPersonalComputerPCRProgramClockReferencePIDPacketIDentifierPMTProgramMapTableppmpartspermillionPRBSPseudoRandomBinarySequencePRNGPseudo-RandomNumberGeneratorPSIProgramSpecificInformationSIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)11PSTNPublicSwitchedTelephoneNetworkPVCPermanentVirtualCircuitQQuadratureQKEQuickKeyExchangeQPSKQuadraturePhase-ShiftKeyingRBDCRate-BasedDynamicCapacityRCSTReturnChannelSatelliteTerminalRFRadioFrequencyRMTRCSMapTableRSReed-SolomonSACSatelliteAccessControlSARSegmentationAndRe-assemblySCTSuperframeCompositionTableSDTServiceDescriptionTableSIServiceInformationSITSatelliteInteractiveTerminalSMATVSatelliteMasterAntennaTelevisionSNAPSubNetworkAccessProtocolSNMPSimpleNetworkManagementProtocolSPTSatellitePositionTableSUTSatelliteUserTerminalSVCSwitchedVirtualCircuitSYNCSynchronizationbursttypeTBTPTerminalBurstTimePlanTCTTime-slotCompositionTableTDMATime-DivisionMultipleAccessTGTrafficGatewayTIMTerminalInformationMessageTRFTraffic(bursttype)TSTransportStreamTxTransmitterUNIUserNetworkInterfaceVBDCVolume-BasedDynamicCapacityVCIVirtualCircuitIdentifierVPIVirtualPathIdentifier4ReferenceModelsforSatelliteInteractiveNetworksinDVB4.1ProtocolStackModelForinteractiveservicessupportingbroadcasttotheenduserwithreturnchannel,asimplecommunicationsmodelconsistsofthefollowinglayers:physicallayer:whereallthephysical(electrical)transmissionparametersaredefined.transportlayer:definesalltherelevantdatastructuresandcommunicationprotocolslikedatacontainers,etc.applicationlayer:istheinteractiveapplicationsoftwareandruntimeenvironment(e.g.homeshoppingapplication,scriptinterpreter,etc.).AsimplifiedmodeloftheOSIlayerswasadoptedtofacilitatetheproductionofspecificationsfortheselayers.Figure1pointsoutthelowerlayersofthesimplifiedmodelandidentifiessomeofthekeyparametersforthelowertwolayers.SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)12AccessmechanismPacketstructureHighermediumlayersProprietarylayersNetworkDependentProtocolsNetworkIndependentProtocolsSynchronizationModulationChannelcodingFreq.RangeFilteringPowerFigure1:LayerstructureforgenericsystemreferencemodelThepresentdocumentaddressesthesatelliteinteractivenetworkdependentaspectsonly.4.2SystemModelFigure2showsthesystemmodelwhichistobeusedwithinDVBforinteractiveservices.Inthesystemmodel,twochannelsareestablishedbetweentheserviceproviderandtheuser:-BroadcastChannel:aunidirectionalbroadbandBroadcastChannelincludingvideo,audioanddataisestablishedfromtheserviceprovidertotheusers.ItmayincludetheForwardInteractionPath.-InteractionChannel:abi-directionalInteractionChannelisestablishedbetweentheserviceproviderandtheuserforinteractionpurposes.Itisformedby:-ReturnInteractionPath(ReturnChannel):fromtheusertotheserviceprovider.Itisusedtomakerequeststotheserviceprovider,toanswerquestionsortotransferdata.-ForwardInteractionPath:fromtheserviceprovidertotheuser.Itisusedtoprovideinformationfromtheserviceprovidertotheuserandanyotherrequiredcommunicationfortheinteractiveserviceprovision.ItmaybeembeddedintotheBroadcastChannel.ItispossiblethatthischannelisnotrequiredinsomesimpleimplementationswhichmakeuseoftheBroadcastChannelforthecarriageofdatatotheuser.TheRCSTisformedbytheNetworkInterfaceUnit(consistingoftheBroadcastInterfaceModuleandtheInteractiveInterfaceModule)andtheSetTopUnit.TheRCSTprovidesinterfaceforbothBroadcastandInteractionChannels.TheinterfacebetweentheRCSTandtheinteractionnetworkisviatheInteractiveInterfaceModule.SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)13ReturnChannelSatelliteTerminal(RCST)Figure2:AgenericsystemReferenceModelforInteractiveSystems4.3ReferenceModeloftheSatelliteInteractiveNetworkAnoverallSatelliteInteractiveNetwork,withinwhichalargenumberofReturnChannelSatelliteTerminal(RCST)willoperate,willcomprisethefollowingfunctionalblocks,asshowninfigure3:-NetworkControlCentre:aNCCprovidesmonitoring&controlfunctions.ItgeneratescontrolandtimingsignalsfortheoperationoftheSatelliteInteractiveNetworktobetransmittedbyoneorseveralFeederStations.-TrafficGateway:aTGreceivestheRCSTreturnsignals,providesaccountingfunctions,interactiveservicesand/orconnectionstoexternalpublic,proprietaryandprivateserviceproviders(databases,pay-per-viewTVorvideosources,softwaredownload,tele-shopping,tele-banking,financialservices,stockmarketaccess,interactivegamesetc.)andnetworks(Internet,ISDN,PSTNetc…).-Feeder:aFeedertransmitstheforwardlinksignal,whichisastandardsatellitedigitalvideobroadcast(DVB-S)uplink,ontowhicharemultiplexedtheuserdataand/orthecontrolandtimingsignalsneededfortheoperationoftheSatelliteInteractiveNetwork.AnRCSTise.g.aSIToraSUTasdescribedin[6].SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)14RCSTNCCSATFWSATRTRCSTNETWORK1NETWORK2InteractiveNetworkAdapterFEEDER1STATIONGATEWAY1STATIONDVBForwardLink1DVBForwardLink2RCSTReturnLinkRCSTRCSTGATEWAY2STATIONFEEDER2STATIONBroadcastNetworkAdapterInteractiveServiceProviderBroadcastServiceProviderFigure3:ReferenceModelfortheSatelliteInteractiveNetworkTheforwardlinkcarriessignallingfromtheNCCandusertraffictoRCSTs.ThesignallingfromtheNCCtoRCSTsthatisnecessarytooperatethereturnlinksystemiscalled"ForwardLinkSignalling"inthefollowing.Boththeusertrafficandforwardlinksignallingcanbecarriedoverdifferentforwardlinksignals.SeveralRCSTconfigurationsarepossibledependingonthenumberofforwardlinkreceiverspresentontheRCST.5ForwardLinkTheRCSTshallbeabletoreceivedigitalsignalsconformingtoEN300421[1],TR101202[2],ETS300802[3],EN300468[4],EN301192[5]andETR154[10].6ReturnLinkBase-bandPhysicalLayerSpecificationandMultipleAccessDefinitionSpecificationsforthebase-bandphysicallayeraregiveninthischapter.Figure4representsthegenericdigitalsignalprocessingtobeperformedattheRCSTtransmitterside,fromtheburstformattingoftheserialinformationbit-stream,tothemodulationrepresentingthedigitaltoanalogueconversion.Thesignalprocessingtobeperformedbyeachsubsetisdescribedinthefollowingsections.SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)15EnergyDispersalInformationdataMACdataChannelCodingBurstformattingI/QburstmodulationModulatedsignalSynchronizationFigure4:BlockdiagramoftheRCSTreturnlinkbasebandsignalprocessing6.1RCSTsynchronization6.1.1TimingControlThesynchronizationoftheRCSTisanimportantfeatureofthesatelliteinteractivenetwork.ConstraintsareimposedontheRCSTstoobtainanefficientTDMAsystemwithminimuminterferencebetweenusersandmaximumthroughput,althoughtheycanbeminimizediftheNCCperformstaskssuchassatellitefrequencytranslationerrorandcommon-modeDopplercompensationforRCSTcarrierfrequency.Forthisreason,thesynchronizationschemeisbasedoninformationcontainedwithintheForwardLinkSignallingasfollows:-NCR(NetworkClockReference);-signallinginDVB/MPEG2-TSprivatesections.TheNCRisdistributedwithaspecificPIDwithintheMPEG2TransportStreamthatcarriestheForwardLinkSignalling.TheNCRdistributionfollowsthePCRdistributionmechanismasdefinedinISO/IEC13818-1[9],whichisusuallyderivedfromanMPEGvideoencoder,whereasheretheNCRisderivedfromtheNCCreferenceclock.TheNCCreferenceclockwillhaveanaccuracyof5ppmorbetter.6.1.2CarriersynchronizationTheMPEG2-TSthatcarriestheForwardLinkSignallingcontainsaNCRinformationwhichprovidesa27MHzreferenceoftheNCCreferenceclocktotheRCSTs.TheRCSTreconstructsthereferenceclockfromthereceivedNCRinformationasimplementedinMPEGdecodersforMPEG2TransportStreams(MPEG2-TS).TheRCSTthenperformsacomparisontodeterminetheoffsetbetweenthelocalreferenceclockwhichcontrolstheRCSTupconverterlocaloscillatorandthereferenceclockrecoveredfromthereceivedNCR.Itthencompensatesthecarrierfrequencyaccordingtothisoffset.ThislocalcarriersynchronizationprovidesawayofadjustingthetransmitfrequencyofallRCSTsonthenetworktoalmostthesamefrequency.Normalizedcarrierfrequencyaccuracyshallbebetterthan10-8(rootmeansquare).6.1.3BurstsynchronizationTheRCSTsretrievethecentrefrequency,thestarttimeandthedurationoftheirtransmitburstsbyexaminingtheforwardlinksignalling(morepreciselytheSCT,FCTandTCTtablesdescribedinsubclause8.3.1).ThecontentionbetweenRCSTsonthereturnlinkisresolvedasdescribedinsubclause6.7.TheburstsaresentaccordingtotheBurstTimePlan(BTP)receivedintheForwardLinkSignalling(seesubclause6.7.2).TheBTPisexpressedintermsofcentrefrequencyandabsolutestarttime(giveninNCR-countervalue)ofsuperframesandassociatedfrequencyandtimeoffsetsofburstallocationsalongwithadescriptionofthetimeslotproperties.AsuperframealwaysstartsatagivenvalueoftheRCSTlocalNCRcounter,whichservesasareferenceforallburstallocationswithinthesuperframe.ForthepurposeofsynchronizingtothenetworktheRCSTreconstructs,inadditiontothereferenceclock,theabsolutevalueoftheNCCreferenceclock.TheRCSTcomparesthereconstructedvaluewiththeNCRvaluegivenbytheBTP.Thetimereferenceforcountingtimeslotsoccurswhenthevaluesareequal.SIST EN 301 790 V1.2.2:2003

ETSIETSIEN301790V1.2.2(2000-12)16Burstsynchronizationaccuracyshallbewithin50%ofasymbolperiod.Theresolutionshallbe1NCRcountinterval.Theburstsynchronizationaccuracyistheworstcasedeviationofthescheduledstartofbursttimeandtheactualstartofbursttimeatthetransmitteroutput.ThescheduledstartofbursttimeisthepointintimewhentheidealreconstructedNCRequalsthevaluewrittenintheTBTPforthatburst.TheidealreconstructedNCRisdefinedasobservedattheoutputofanidealdelay-lessDVB-Sreceiver.Compensationforthereceiverdelay,ifrequiredtoachievethespecifiedaccuracy,shallbedonebytheRCST.6.1.4SymbolclocksynchronizationThesymbolclockforthetransmittershallbelockedtotheNCRbasedclock,inordertoavoidtimedriftwithrespecttotheNCCreferenceclock.TheRCSTneednotcompensateforsymbolclockDoppler.Symbolclock
...