DESIGN AND IMPLEMENTATION OF AN SCA CORE FRAMEWORK FOR A DSP

The Software Commuications Architecture (SCA) was developed to improve software reuse and interoperability in Software Defined Radios (SDR). However, there have been performance concerns since its conception. Arguably, the majority of the problems and inne

DESIGNANDIMPLEMENTATIONOFANSCACOREFRAMEWORKFORADSP

PLATFORM

CarlosR.AguayoGonzalez(MPRG,Wireless@VirginiaTech,Blacksburg,VA,USA;caguayog@vt.edu);FranciscoPortelinha(UniversidadeFederaldeItajuba,Itajuba,MG,Brazil,portelinha@uti.psi.br);and

JeffReed(MPRG,Wireless@VirginiaTech,Blacksburg,VA,USA;reedjh@vt.edu).

ABSTRACT

TheSoftwareCommuicationsArchitecture(SCA)wasde-velopedtoimprovesoftwarereuseandinteroperabilityinSoftwareDe nedRadios(SDR).However,therehavebeenperformanceconcernssinceitsconception.Arguably,themajorityoftheproblemsandinne cienciesassociatedwiththeSCAcanbeattributedtotheassumptionofmodulardistributedplatformsrelyingonGeneralPurposeProcessors(GPPs)toperformallsignalprocessing.Signi cantimprove-mentsincostandpowerconsumptioncanbeobtainedbyutilizingspecialized,moreef cientplatforms.DigitalSignalProcessors(DSPs)presentsuchaplatformandhavebeenwidelyusedinthecommunicationsindustry.ImprovementsindevelopmenttoolsandmiddlewaretechnologyopenedthepossibilityoffullyintegratingDSPsintotheSCA.Thisapproachtakesadvantageoftheexceptionalpower,cost,andperformancecharacteristicsofDSPs,whilestillenjoyingthe exibilityandportabilityoftheSCA.

ThispaperpresentsthedesignandimplementationofanSCACoreFramework(CF)foraTITMS320C6416DSP.TheframeworkisdeployedonaLyrtechQuad-SignalMasterC6416board.TheSCACFisimplementedbyleveragingOSSIE,anopen-sourceimplementationoftheSCA,tosup-porttheDSPplatform.Prismtech’se*ORBandDSP/BIOSareusedasthemiddlewareandoperatingsystem,respec-tively.Asamplewaveformwasdevelopedtodemonstratetheframework’sfunctionality.Benchmarkresultsfortheframeworkandsampleapplicationsareprovided.

1.INTRODUCTION

TheSoftwareCommunicationsArchitecture(SCA)wasde-velopedbytheJointTacticalRadioSystem(JTRS)pro-gramoftheUSDepartmentofDefensetostandardizethedevelopmentofSoftwareDe nedRadio(SDR)technology.TheSCAwasdevelopedtoenhancesystem exibilityandinteroperability,whilereducingdevelopmentanddeploymentcosts.EarlyimplementationsofSCASDRshavestruggledtomeetperformance,cost,size,andpowerrequirements.Arguably,manyofthetheseproblemshavetheiroriginintheassumptionofamodular,distributedplatformbasedonGeneralPurposeProcessor(GPP)toperformallsignalprocessing.

Inordertoovercometheseproblems,itisnecessarytomakebetteruseofspecializedhardwareoptimizedforsignalprocessing.DigitalSignalProcessors(DSP)arespecializedmicroprocessorsdesignedspeci callyforreal-timedigitalsignalprocessing.However,DSPshavebeenrelegatedas

secondaryelementsintheSCA,requiringaHardwareAb-stractionLayer(HAL)forconnectivity.Ongoingimprove-mentsindevelopmenttoolsandmiddlewaretechnologyal-lowtheimplementationofSCAsystemsusingonlyDSPs.Byfollowingthisapproachthe exibilityandreusabilitybroughtbytheSCAarecomplimentedbythecostandpoweref ciencyofDSPs.Iftakentoalogicalextent,thisapproachcouldeliminatetheneedforaGPPoncertainSDRimplementations.InthispaperwepresentthedesignanddevelopmentofanSCAimplementationforahomogeneousTIDSPplatform.

2.SYSTEMARCHITECTURE

Thegoalofthisprojectistostudytherepercussionsofimple-mentingtheSCAinanoptimizedDSPplatform.Therefore,weaimtominimize,oreliminate,theuseofGPPsforthisimplementation.WeleveragedtheexistingimplementationofMPRG’sOpenSourceSCAImplementation::Embedded(OSSIE)[2],byportingittotheC64platform.ThesystemimplementstheSCAversion2.2inC++.OurdevelopmentenvironmentisTICodeComposerStudiorunningonaWindowsPC.MostofthedevelopmentisdoneusingtheDeviceAccuratesimulatoroftheC6000.The naltargetplatformisaSignalMasterQuadfromLyrtech.2.1.SoftwareArchitectureElements

ThegeneralsoftwarestructurecanbeseeninFig.1,show-ingthethreedifferentcomponentsoftheSCAOperationalEnvironment(OE):theCoreFramework(CF),ORB,andoperatingsystem.InthisprojectweusedOSSIEastheCF,e*ORBfromPrismTechasmiddleware,andDSP/BIOSasReal-TimeOS.Allofthemareavailablecommerciallyorasopensource.Services(e.g.Log,Event,andNamingServices)arenotconsideredintheinitialimplementation.

DSP/BIOSisascalablereal-timemultitaskingoperat-ingsystemdesignedspeci callyfortheTMS320familyofDSPs[4].ItisdevelopedandmaintainedbyTexasInstruments.DSP/BIOSisbuiltinmoduleswhichallowsdeveloperstoreducethefootprinttoaminimumbyonlyinte-gratingthefeaturesthatarestrictlynecessaryforoperation.Itsupportspreemptivemultithreadedoperationsthankstoarealtimeschedulerandprovidesmemorymanagementmodulesforlowoverheaddynamicmemoryallocation.DSP/BIOSisnotPOSIXcompliant,asrequiredbytheSCA,forcingaslightdeviationfromthespeci cations.TheC6000familyofprocessorsdoesnotincludeamemorymanagementunit.

The Software Commuications Architecture (SCA) was developed to improve software reuse and interoperability in Software Defined Radios (SDR). However, there have been performance concerns since its conception. Arguably, the majority of the problems and inne

Fig.1.SoftwareStructure

TheORBusedinthisprojectisPrismTech’se*ORBSDRC++versionforDSP.ThisisacustomportoftheircommerciallyavailableCversion,averyoptimized,modularimplementationofminimum-CORBAasstandardizedbytheObjectManagementGroup(OMG).However,Prismtechhasreleasedthisversiontothegeneralpublic[3].e*ORBsupportstheExtensibleTransportLayer(ETF)whichallowscustomtransportplug-ins.

2.2.Platform

ThetargetplatformforthisprojectistheSignalMasterQuadC6416fromLyrtech[1].Thishighperformanceboardcon-tainsfourTITMS320C6416TDSPsandtwoXilinxVirtexIIFPGAsdividedintotwoclusters(oneFPGAandtwoDSPseach).Thesystemrunsat720MHzandhas128MbytesofSDRAMmemoryperDSP.ThereisahighspeedbusbetweenbothFPGAsimplementedusingLVDS.Thecom-municationbetweentwoDSPswithinthesameclustercanbeimplementedusingsharedmemoryorFastBus,aproprietaryprotocoldevelopedbyLyrtech.Inthisproject,onlyDSPsareusedforsignalprocessingandframeworkfuncti …… 此处隐藏：19011字，全部文档内容请下载后查看。喜欢就下载吧 ……