short/mid-reach 10spe phy with multipoint claude gauthier
TRANSCRIPT
A15/40mPHYCandidate• Ashort-reach(15/40m,4conn)forpoint-pointinterface– Goal- a50%reductioninpower,area,pinsrelativeto100BT1
July2017 2zimmerman_3NEA_01_061417.pdf
10Mb/sSPEPHYStrawman
• Simplifythesignalingtobinarylevels• DME(DifferentialManchesterEncoding)• TX- ClassABtransmitter@20MHz• RX- Analogequalizer,comparatorsforreceive,• RX- LargelyeliminateDSP,exceptforfloatingEQ
10Mb/sSPEPHYPackageDesign• Canthepackagefollowthesiliconareareduction?
• A100BT1discrete PHYmayhave36pins• Powersupplypinswillscalesignificantly• MIIis16pins,asignificantpercentageofthetotal
• Canreducethisto4pinswithoutchangingtheMACinterface:“xMII”• cordaro_thaler_10SPE_01a_0916.pdf
MLT3
• A14-pinpackageisreasonableforthisprotocol
-75%
10Mb/sSPEPHYDesign• Area<~25-30%of100BT1area
• This isapproximatelytheareaof100Base-TX
• PowerDissipation<~33%of100BT1• Powerreductionsupportsreductionofpackagepins• Importantgiventhenumberof10Mb/snodes inthenetwork
• Low-powerdriveslowpin-countpackages
Conclusion: Yes, it’spossible toreducesiliconarea/powerby>50%
WhatAboutMultipoint?• Increasessignal-integritychallengerelativetothebaseline,butitcanbemanaged
• Needtofixinsertionloss,delay,numberofnodes– Somemodelsexistforautomotive,needtoexpandthelistforotherusecases(i.e.cabinets,buildinginfrastructure)
• Biggerchallengeisaddressingtheimplicationsof“sharing”versuspoint-point
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matheus_10SPE_01_0417.pdf
WhatAboutMultipoint• Forthissimple,traditionalPHYcanweaddcircuitrytoimplementCMAS/CD?– Showspromise,leveragesexistingPHYtopologieswithsomeadditionalmodifications
– Costsnetworkperformanceandplaceslimitationsonphysicalconstraints
• Alternative- TDMA-based– CanalsoleveragetraditionalPHYarchitectures,buttheoverallsolutioniscompromised:• Inefficient allocationofresources• Allocatetime-slots fornodesANDallocatetime-slots inbetween• Fixednumberofnodes, time-syncchallengesgivenvariablespacing
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HowAboutFDMA?• Thefrequencydomainisacleanwayto“share.”– Everyonecantalkatthesametime,nodesgothroughaset-upandareallocatedafixed-channel
• Betternetworkperformance,opensthedoortolowerpower(analogimplementation),butit’sdifferent/new
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FDMA-Conceptual• Leveragessimplelow-power/low-costmultichannelwirelesstopologies
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– FrequencyAllocation• Firstconsider4channels• Usealltheavailablebandwidth (i.e.100MHz?)andallocateindividual10MHzchannels– ORuse36MHz(“sweetspot bandwidth”)andrelyonencodingtoget10Mb/sfrom4MHzchannels
ParallelHead-EndTransmitterConceptual
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+xejω3t
Channel3modulation
xejω4t
Channel4modulation
xejω1t
Channel1modulation
xejω2t
Channel2modulation
Headendouttolineinterface
ParallelHeadEndReceiverConceptual
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+xe-jω7t
Channel7baseband
xe-jω8t
Channel8baseband
xe-jω5t
Channel5baseband
xe-jω6t
Channel6baseband
Headendouttolineinterface
Single-NodeTransmitter/ReceiverConceptual
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xe-jω1t
Channel1baseband
Outtolineinterface
xejω5t
Channel5modulation
MoreInformationNeeded• Auto-negotiationandchannelassignment• Link-Segment– Channelconditionsfornon-automotivemid-reachmulti-dropcases
– Fixonmax/minconditions– Connectorcharacteristics
• Powerestimationandcomplexityanalysisforbothtopologies
July2017 13