Novel VLSI Design & Verification Strategies for Advanced Wireless Technologies

This whitepaper proposes novel VLSI design and verification strategies for 4G LTE /5G LTE-Advanced wireless technologies to meet the challenges like time-to-market in emerging wireless market in the telecom vertical.

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Novel VLSI Design & Verification Strategies for Advanced Wireless Technologies from HCL Technologies

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• 1. NovelVLSIDesign&VerificationStrategiesfor AdvancedWirelessTechnologies
• 2.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. Abstract Abbreviations Markettrend/Challenges Solution BestPractices CommonIssues ConclusionConclusion Reference AuthorInfo 3 3 4 4 9 9 99 10 10 TableofContents
• 3.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. RecentlytherehasbeenanincreaseintheusageofVLSIsolutionslikeFPGA/ASICinwirelesssystems,replac- ingtheearlierusedDSPprocessors.NowmostoftheLayer1-PHYLayerisgettingdoneinFPGAtomeetthe highbandwidth/throughputrequirements.ThisisbecauseDSPsavailableinthemarketarenotabletomeet thecomplexityandtiming.AlsotheonlychoiceforDigitalIFProcessingFunctionisFPGAssincehighsampling rateprocessingisnotpossibleinDSPs.Inthiswhitepaper,weproposenovelVLSIdesignandverification strategiesfor4GLTE/5GLTE-Awirelesstechnologiestomeetthechallengesliketime-to-marketinemerging wirelessmarketinthetelecom vertical. Sl.No 1 2 3 4 5 6 77 8 9 10 11 12 13 1414 15 16 17 18 VLSI FPGA ASIC DSP LTE LTE-ALTE-A OFDMA MIMO FFT/iFFT FEC SV DigitalIF BFMBFM GMAC RTL TTI BTS IO VeryLargeScaleIntegration FieldProgrammableGateArray ApplicationSpecificIntegratedCircuit DigitalSignalProcessors/Processing LongTerm Evolution LTE-AdvancedLTE-Advanced OrthogonalFrequencyDivisionMultipleAccess MultipleInputMultipleOutput FastFourierTransform/InverseFastFourierTransform ForwardErrorCorrection System Verilog Digitalintermediatefrequency BusFunctionalModelBusFunctionalModel GigaMultiplyAccumulates RegisterTransferLevel TransmissionTimeInterval Basetransceiverstation InputandOutput FullFormAcronyms Abstract Abbreviations NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |3
• 4.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. VLSIsolutionslikeFPGA/ASICcontinuetogainmomentum byfastreplacingtheearlierDSPprocessorsin wirelesssystems.Thisisbecausehigh-endFPGAssupportalargenumberofembeddedDSPblocksleading tooperationsatGMACswhoseorderofmagnitudearegreaterthantheperformanceofDSPsavailableinthe market.ThecurrentleadingFPGAvendorsareXilinxandAltera.Forexample,Altera-StratixVGS(5SGSD8) serieshave695KLogicElements,1050KRegisters,2567–M20KMemoryBlocksandvariableprecisionDSP blockssupportingupto3,926-18x18multiplierswhichisequivalentto1,963DSPBlocks.Withthis,wecan configureconfiguretonativelysupportsignalprocessingwithprecisionrangefrom 9x9to36x36includingfloat- ing-pointimplementations[1] .Xilinx–Vertex7serieshave2millionlogicgates,85MbblockRAMand3,600DSP blocks[2] . Also,mostoftheLayer1-PHYLayerisgettingdoneinFPGAduetotheinabilityoftheavailableDSPstomeet thehighbandwidth/throughputrequirements.FPGAsaremoresuitableforDigitalIFProcessingFunctionas wellsincethehighsamplingrateprocessingisnotwellsupportedbytheDSPs.Thiswhitepaperproposes novelVLSIdesignandverificationstrategiesfor4GLTE/5GLTE-Awirelesstechnologiestomeetthechallenges liketimetomarketinemergingwirelessmarketintelecom vertical. Timetomarketisakeyparameterwhichdeterminesthesuccessof4GLTE/5GLTE-Advancedwirelesstech- nologiessystemsduetodemandingmarketcompulsionslikeshortlife-spanofsmartphones,tabletsand otherdeviceswhichusethesewirelesstechnologies.ThesewirelesstechnologiesarebasedonMIMO-OFDMA system[3] andoptimalHW/SW partitioningforsuchMIMO-OFDMAsystem[4] .TheHW portionofMIMO-OFDMA needstobeimplementedonFPGA/ASICsusingVLSIdesign,developmentandverificationtechniques.The gatecomplexityofthesedesignsisveryhighoftheorderof10Milliongates.Inthiswhitepaper,wepropose somesomenovelVLSIdesign&verificationstrategiestomeetthetimetomarketrequirementforsuchhighcom- plexityMIMO-OFDMAbasednextgenerationwirelesssystemsaslistedbelow. Adoptingsystem leveldesignmethodology,insteadofbehavioralleveldesignmethodologyto developFPGAprototype(proto) AdoptingadvancedverificationtechniquesinPre-Silicon(Pre-Si)verificationinsteadofsimpleFile I/Obasedtechnique FPGAprototypinginparalleltoASICdevelopment Post-siliconvalidationonFPGAprotoinparalleltoPre-Siverification Markettrend/Challenges Solution NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |4
• 5.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. Thetraditionaldesignmethodologytoimplementthedigitalsignalprocessing(DSP)blocksinFPGA/ASIC isbyusingbehaviorallevelofRTLcoding,whichisverytimeconsumingprocesstodeveloptheDSPblocks. ItalsorequireshighlyskilledDSPexpertsanddesignengineersforimplementation.Eventhiscoding methodologyactuallyevolvedfrom,switchlevelgateleveldataflow behaviorallevelabstractionof hardwaredescriptionlanguage(HDL)developmentasdesigncomplexitybecamemorecomplexinthe orderof10/100/1000/10000gatesrespectively.Asperthecurrentindustrytrends,behaviorallevelofRTL codingcodingusedasthegatecomplexityismorethan10,000gateswhichisgenerallyreferredtoasVLSIdesign. However,4G/5Gwirelesstechnologynecessitatesveryhighdesigncomplexityoftheorderof10Million gates,hencetodevelopthesesystem onemorelevelofabstractioni.e.system levelofabstractionis requiredintermsoftimetomarket,easytodesign,verificationandvalidation. 1.System LevelDesignMethodology 1.1TraditionalDesignMethodology ForhighlycomplexsystemslikeBaseStations(BTS)for4G/5Gdevelopmentsystem,before goingtothe ASICchipsetdevelopment,FPGAprototypingisnecessaryforproofofconcept.CurrentleadingFPGA vendors,bothXilinxandAltera,provideaplatform forsystem leveldesign. Altera-Altera-Qsys&MegacoreGUItool[1] ,haveDSP&IOinterfacefunctionlikeFFT/iFFT,FECblocks,Filters,CPRI, Ethernet,DMA,RAM/ROM,FIFO,Arbiter,SerDes,PLLetc.Basicallyallthesystem designcomponentsare availableintheAlteratoolitselfandthesecomponentsareeasilyinterconnectedwithAlteraproperty interfacelikeAvalon® –ST(streaming)andMM (MemoryMapped)interface.Byproperlyconfiguringand interfacingthesereadymadeblocks(GUIbaseddraganddrop)inQsysdesignsystem console,wecan easilybuildourownsystem andthiskindofdesignmethodologyisreferredassystem leveldesignmeth- odology.odology.SomeDSPblockslikeTurbo/LDPCdecodersmaynotbeavailableintheAltera-Qsyslibrary,for thisblockwecangeneratethedesignandtestbenchHDLcodeoutputfrom MATLABHDLCoder™tool whichneedstobeusedinconjunctionwithMATLABSimulinktool.WecanmanuallywritetheHDL wrapperandintegratewithQsyscomponentwhichisverylesstimeconsumingprocess. Xilinx-Vivado™[2] ,designsuiteprovidesthecompleteSOCdesignplatform.Mostofthesystem design modulesareavailableintheXilinxSmartCore™andLogiCORE™IPtoolitself.RTLcodeofDSPblockslike turboencoder/decodercanbegeneratedfrom theVivadoHigh-LevelSynthesis(HLS)tool,whichconverts theC/C++/System CdesigntoRTLdesign.EventhoughtheRTLcodeobtainedfrom thetool,itwillbe betteroptimizedthanhandwrittenHDLcode.VivadoIPIntegratortoolprovidesGUIbasedplugandplay componentswhichisinterconnectedbyAXIinterface,apartfrom thatFPGAitselfhavetheARMprocessor whichwillprovidemoreelegantsolutions. 1.2System LevelDesignMethodology NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |5
• 6.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. Thebenefitsofsystem leveldesignmethodologyare: Hencethesystem leveldesignmethodologyiswellpredictableandthebestengineeringapproachfor highlycomplexsystemslike 4G/5Gtechnologiesastheabovebenefitsleadtoquicktimetomarketsolu- tions. Reductioninthedesigncycletimedrastically Reductioninthedesignengineerheadcount Theseblocksareverifiedandvalidated,hencelowrisk QuickFPGAprototyping,whichisproofofconceptforanynewsystem designidea/approach. Lowcostproduct 2.AdvancedPre-SiVerificationStrategies TheinputtestvectorsandexpectedoutputtestvectorsaregeneratedbyusingDSPalgorithmsreference Matlab/Cmodel.BitaccuracycheckerinSystem VerilogcomparestheRTLblockoutputVsexpectedresult andthisissimpleverificationmethodology.Thisstrategymaynotbeenoughtotestallthecornercases andstresstestingofhighlycomplexsystem like4G/5Gwirelesssystems. Figure1:TraditionVerificationStrategy 2.1TraditionalVerificationStrategy-FileI/OMethod NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |6
• 7.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. InthisstrategyCmodeloftheDSPalgorithm needstobeintegratedwithSystem VerilogbyusingDPI (DirectProgrammingInterface)techniqueortheMATLABmodeloftheDSPalgorithm needstobeinte- gratedwithEDAsimulatorlinktool.Withthismethodology,wecangeneratethetestvectorontheflyand wecanperform theconstrainedrandom unit/integration/regressionverificationmoreefficiently.Wecan alsoverifythemagnitudeandphaseplotsagainsttheMATLABmodelautomatically.Aspartoftheregres- sionverificationforfilters,functionaltestingisdonewiththefollowingtypeofinputvectors,impulse(for latencyandgroupdelay),sine,stepforgain,multitoneandrandom vectors. Figure2:AdvancedVerificationStrategy 2.2AdvancedVerificationStrategyusingC/MATLABreferencemodel FPGAprototypeplatform isproofofconceptfortheideaanditisusefulforfunctionalvalidationhowever withlower/reducedthroughputlevelsinceFPGAdesignrunsatlowerclockfrequencycomparedtoASIC. TheadvantagesofFPGAproto-typingare: DUT Checker (SV) TestInput Generation (SV) SVWrapper (DP) CCode RealTimeWorkshop (MatlabtoCconversion) (Embedded)Matlab FixedPointToolbox SignalProcessing Toolbox System VerilogTest Environment ReferenceModel (CCode) 3.FPGAPrototyping NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |7
• 8.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. FPGAprototypingplatform helpfultovalidatethedriver-software. Real/actualdatacanbeinjectedintothedesign,bywhichwecanidentifythemetastabilityissues, simulationandsynthesismismatch. RealHardware(CPRIandSerDes)canbevalidatedintheFPGAwhichwillbringupthefunctional modelissues,ifany. WeWecantestallpossiblerandom patterntestsequencegenerationinperiodicinterval(dai- ly/weekly)tovalidateallthefeaturesoftheSOC. Memorysize Functionalvalidationunderextremethermalconditionsbyintensivelyheating TimingandVoltageparametervalidation Signalintegritytesttovalidatethecriticalsignalslikereset,clock,controlsignals,etc., ATPG(AutomaticTestPatternGeneration)whichwillinjectthetestvectorsintothechip Hardwareinterfacetestlikeboarddiagnostictest-sanitycheck,poweredsignaltest FrequencyclockmargintestFrequencyclockmargintest LowVoltageVsLow/HighTemperaturetestandviceversa Eyediagram,Timingmargin,Rise/Falltime,Jitter,BER–BitErrorRatiomeasurementtest LoopbacktesttovalidatetheprotocollikeCPRI,Ethernet,etc. Poweronresettest NoiseImmunitytesttovalidatethenoisemargin 4.Post-SiliconValidation PostSiliconValidationneedstobeperformedtogetherbymanufactureranddesignteam.Inthismethod- ologywecantestallchipIOswithfullthroughput,whichwillverifyalltheDSPblocksthroughput,arbiter speedandbus/bridgefunctionality.InFPGAproto-typingwewillhavethelimitationofspeedwhichwill notbethereinpost-siliconvalidation.Wecanvalidatethefollowingfeaturesinpost-siliconvalidation: Figure3:PostSiliconValidationStrategy Chipset (FPGA/ASIC-SOC) PC (Windows/LinuxPlatform) ValidationEnvironment TestGenerationHardware (AutomaticTestingMachine) NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |8
• 9.©2015,HCLTechnologies.ReproductionProhibited.ThisdocumentisprotectedunderCopyrightbytheAuthor,allrightsreserved. BestPractices CommonIssues Conclusion Whentheproposeddesignandverificationstrategiesareadoptedcomparedtoothertraditionalstrate- gies,therewillbedefinitebenefitsinthefollowing 1.Meetingthetiming:Itmeanssatisfyingthereal-timeprocessingrequirementsspecifiedinthe standardwhichisTTIof1msforLTE. 2.Reliability:Sincetheproposedstrategiesensurereliabilitybymorethanonemeans,likepost-silicon validationinadditiontopre-siverification,theoutcomeofthesestrategieswouldbehighlyreliable. 3.Scalability:Asthestandardsevolvemorefeatureswouldgetadoptedandduetoscalablenatureof ourproposedstrategiesitcanbeeasilyadoptedfornewerversionsofthestandards. 4.TimetoMarket:4.TimetoMarket:Alltheproposedtechniques,ifusedeffectively,willgetadefiniteadvantageintimeto marketcomparedtotraditionalstrategiesparticularlytheparallelpost-siliconvalidationonproto. Althoughtheproposedstrategieshavedefinitebenefits,someofthechallengesintheproposedsolutions maybe: TheproposedVLSIdesign,verificationandvalidationstrategyisdefinitelyagoodapproachforLTE/LTE-A Layer-1developmentascomparedtothetraditionalapproaches.Thissolutiongivesanedgeintimeto marketwiththeflexibilityandrapidprototypingcapabilities,whichisacriticalparameterin4GLTE/5G LTE-Advancedwirelesstechnologiessystemsduetotheshortlifespansofthedeviceswhichusethem.The proposedstrategyalsoprovidesadditionalbenefitsofmeetingthetiming,reliabilityandscalability. 1.Requiresachangeinmindsetoftheengineerstoadapttheproposedstrategiescomparedtotradi tionalstrategies 2.Toolcostforadoptingsomeoftheproposedstrategiesishighercomparedtotraditionalstrategies NovelVLSIDesign&VerificationStrategiesforAdvancedWirelessTechnologies |9
• 10. Formoredetailscontact:ers.info@hcl.com Followusontwitter:http://twitter.com/hclersand Ourbloghttp://www.hcltech.com/blogs/engineering-and-rd-services Visitourwebsite:http://www.hcltech.com/engineering-rd-services Hello,I’m from HCL’sEngineeringandR&DServices.Weenabletechnologyledorganizationstogotomarketwithinnovativeproducts andsolutions.Wepatnerwithourcustomersinbuildingworldclassproductsandcreatingassociatedsolutiondeliveryecosystems to help bringmarketleadership.Wedevelop engineeringproducts,solutionsand platformsacrossAerospaceand Defense, Automotive,ConsumerElectronics,Software,Online,IndustrialManufacturing,MedicalDevices,NetworkingandTelecom,Office Automation,SemiconductorandServers&Storageforourcustomers. ThiswhitepaperispublishedbyHCLEngineeringandR&DServices. Theviewsandopinionsinthisarticleareforinformationalpurposesonlyandshouldnotbeconsideredasasubstituteforprofessional businessadvice.TheusehereinofanytrademarksisnotanassertionofownershipofsuchtrademarksbyHCLnorintendedtoimply anyassociationbetweenHCLandlawfulownersofsuchtrademarks. FormoreinformationaboutHCLEngineeringandR&DServices, Pleasevisithttp://www.hcltech.com/engineering-rd-services Copyright@ HCCopyright@ HCLTechnologies Allrightsreserved. CSaminathan HCLEngineeringandR&DServices GSangeet HCLEngineeringandR&DServices DrGVRangaraj HCLEngineeringandR&DServices Reference AuthorInfo 1.AlteraFPGAandTools-http://www.altera.com 2.XilinxFPGAandTools-http://www.xilinx.com 3.3GPPLTEStandards:TS36.201,TS36.211&TS36.212 http://www.3gpp.org/ftp/Specs/html-info/36201.htm http://www.3gpp.org/ftp/Specs/html-info/36211.htm http://www.3gpp.org/ftp/Specs/html-info/36212.htm 4.Altera’sWhitepaperonDSP-FPGASystemPartitioningforMIMO-OFDMAWirelessBasestations,October20074.Altera’sWhitepaperonDSP-FPGASystemPartitioningforMIMO-OFDMAWirelessBasestations,October2007 AdoptingthePairwiseTestDesignTechniquetoOptimizePrinterDriverTestCoverage |10