soware defined radio (sdr) architecture and systems...
TRANSCRIPT
So#wareDefinedRadio(SDR)ArchitectureandSystemsIssues
WorkshoponSpacecra#FlightSo#ware(FSW‐09)
2009‐11‐6
KennethJ.PetersJetPropulsionLaboratory,CaliforniaIns9tuteofTechnology
Introduc9on• Speaker• NASASTRS– SpaceTelecommunica9onsRadioSystem
• JPLImplementa9on
• SystemsIssues
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ThisresearchwascarriedoutattheJetPropulsionLaboratory,CaliforniaIns9tuteofTechnology,underacontractwiththeNa9onalAeronau9csandSpaceAdministra9on.
Referencehereintoanyspecificcommercialproduct,process,orservicebytradename,trademark,manufacturer,orotherwise,doesnotcons9tuteorimplyitsendorsementbytheUnitedStatesGovernmentortheJetPropulsionLaboratory,CaliforniaIns9tuteofTechnology.
©2009CaliforniaIns9tuteofTechnology.Governmentsponsorshipacknowledged.
Speaker• JPLsoFwareengineerfor15+years– SoFwareleadforElectraradiosoFwareforMROandMSL
• HelpeddraFandreviewNASASTRSspecifica9on– Specisreleased,butimprovementisongoing
• OneofseveralsoFwareengineersdevelopingtheJPLimplementa9on– JPLimplementa9onisoneofseveraltohelpshakeoutthespecifica9on
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NASASTRS• CombinedeffortbyseveralNASAcenterswithinputfromindustry
• Released(v1.02)hardware,FPGA,andsoFwarearchitecturestandard– Intendedtoallowcross‐pla]ormportabilityofcommunica9onimplementa9ons
– Alllayersandsignalprocessing• Leanstowardrequiringinterfacedocuments,ratherthanspecificinterfaces– ExceptforsoFware
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ConceptualBlockDiagram
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BasicSTRSSWBlockDiagram• STRSAPI– Controlandinterac9on– Similarto• OMG/SWRADIO• OMG/SCA(JTRS)
– Generallylighterweight• POSIXRTOS– orcompa9bilitylayer
• Devicedrivers– POSIXand/orSTRS
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STRSApplica9ons• TheCPUandFPGAsoFwarethatmakesthebox“bearadio”
• Intendedtobeportableacrosscompa9blepla]orms– UseSTRSandPOSIXAPIs– Useservicesprovidedbypla]ormvendorthroughSTRSAPIs• SuchasspacecraFinterfacehandlers(commandsandtelemetry)
– Accesshardwareviadevicedrivers• Mayneedtodevelopcompa9bledriversondifferentpla]orms
– UsedefinedandflexibleinterfacestoandwithinFPGAs
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JPLImplementa9on• BasicarchitecturalfeaturesrunonLinuxpla]orm– Allowseasierdevelopment– Demonstratesbasicopera9ngsystemportability
• Targetedtocustomradiohardwareforfullimplementa9on– AtmelAT697SparcCPU– UsingtheRTEMSPOSIXcompliantRTOS
• Opensource• SupportsAT697CPU
– DevelopingcustomRTEMSPOSIXdevicedrivers– DevelopingcustomFPGAmodulesforabstrac9on
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JPLImplementa9on
• S9ckingto“plainC”exceptwherenecessarytointeractwithC++STRSapplica9ons– Nodtohighlyconserva9vespacecodingenvironment– WanttosupportC++applica9onsdevelopedbyothers
• Applica9onssta9callylinkedwithenvironment– Registra9onfunc9onsforC++objectorCentrypoints– Applica9onstartupandcontrolviaSTRSAPIfunc9oncommands
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JPLImplementa9on
• DevelopingasimplemodularFPGAmethodology– AssignmoduleIDcodesfordifferentmodulesthatmaybecombinedintoanFPGAbi]ile• ModuleIDimpliesfunc9onalityandinterfacespecifica9on
• Alsohaveversioncodesforupdates– DefineregisterbaseaddressesforFPGAmodules• Definedwhenmodulesarebroughttogetherintoabi]ile• Eachmoduleinternallydefineswhateverregistersitwants
– MakebaseaddressesandmoduleIDcodesavailabletosoFwareinregistersattheknownbaseaddressoftheen9reFPGA
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SystemsIssues
• ThechangeablenatureofthesoFwaredefinedradiomayleadtochangingconceptsofhowthelocalspacecraF,theground,andremotespacecraFinteractwithradios
• Possibleapplicabilitytosystemsissueswithmorecomplexinstrumentsingeneral
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RequirementsSpecifica9on• Boundaries/interfaceslikelytobeindifferentplacesthanintradi9onalradios– Conceptualblockdiagramdivisionsmaynotmatchphysicaldivisions
– Differentdesignersatdifferentlayerstendtosharephysicalresources
• Performancespecifica9onsalsobreakapartindifferentways– Needtoclearlydefineperformanceateachconceptuallayer,whichmaybedevelopedindependently
– Ratherthanend‐to‐endwithassump9onofsinglecoordinateddecomposi9on
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CPU/FPGAInterac9on
• ItisexpectedthatboththeCPUsoFwareandtheFPGAbi]ilemaychangetoprovidedifferentradiofunc9ons
• Clearandflexibleinterfacedefini9onsareneeded– BothbetweenandwithinCPUandFPGAcode– Sothatmul9pleprogrammersofbothCPUandFPGAcodecanworkindependentlyandportably
• Clearandflexibleversioniden9fica9onandcontrolareneeded– SothatmismatchedsoFwareandbi]ilescanbeavoided
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Command/ControlComplexity
• SDRstendtohavemorecommandsandmodesthantradi9onalradios
• Commandset,andtelemetryformats,mayvarydependingonwhatsoFwareisloaded– Andmaydifferfromradio“safemode”ifany
• Thismaybeaproblemfortradi9onalspacecraFandgroundcommand/controlmethods– Mayneedcoordinated“soFwaredefined”interfacesthroughoutthesystem,ormorestandardizedinterfaces
– OrSDRsmayneedtohavemoreinternalautonomyKenPeters
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“Iwantaradio,notarela9onship”–GlennReeves
Con9nua9on• Notaconclusion,anongoingexplora9on• MayneednewmodelsforthespacecraFbusprotocol¿Morelike“plugandplay”,withdriverdiscoveryasinPCI?¿Morelikemanagingnetworkhosts,withautoconfigura9onasinSNMP?
¿Morelikenetservicesorserviceorientedarchitecture,withdiscoverableinterfacesasinWSDL?(WebServicesDescrip9on
Language)
¿?
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