Basic of Small Cell and precision timing devices of Small Cell and precision timing devices ......
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T T T e e echnical chnical chnical chnical Notes Notes Notes Notes 1 Basic of Small Cell and precision timing devices TN151210TD Over view Small Cell is a thin client communication Base Station that significant contributions can be expected to cost the suppression of proliferation and infrastructure of traffic in the Internet community. Small Cell is expected in addition to the previous Macro Cell, to put the next generation communication system (4G to 5G). In this article for beginner shows the role of Small Cell, features, and, requirement reasons of high precision clock, and introduce a EPSON timing device solutions of optimal applications. ڭSmall Cell’s role We show in the illustrations of the major role of the Small Cell on Figure 1 and Figure 2. Figure 1= Small Cell serves to supplement the communication quality at dead zone (red area, before implementation) that existing Base Station cannot be covered (orange area). Figure 2= Small Cell can cover traffic overflow with existing base station at where a large number of communication people area. Figure 1: Small Cell’s role case1 Figure 2: Small Cell’s role case2
Transcript of Basic of Small Cell and precision timing devices of Small Cell and precision timing devices ......
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Basic of Small Cell and precision timing devices
TN151210TD Over view
SmallμCellμisμaμthinμclientμcommunicationμBaseμStationμthatμsignificantμcontributionsμcanμbeμexpectedμtoμcostμtheμ
suppressionμofμproliferationμandμinfrastructureμofμtrafficμinμtheμInternetμcommunity.μSmallμCellμisμexpectedμinμadditionμ
toμtheμpreviousμMacroμCell,μtoμputμtheμnextμgenerationμcommunicationμsystemμ(4Gμtoμ5G).μ
InμthisμarticleμforμbeginnerμshowsμtheμroleμofμSmallμCell,μfeatures,μand,μrequirementμreasonsμofμhighμprecisionμclock,μ
andμintroduceμaμEPSONμtimingμdeviceμsolutionsμofμoptimalμapplications.μ
Small Cell’s role WeμshowμinμtheμillustrationsμofμtheμmajorμroleμofμtheμSmallμCellμonμFigureμ1μandμFigureμ2.μ
Figureμ 1=μ Smallμ Cellμ servesμ toμ supplementμ theμ communicationμ qualityμ atμ deadμ zoneμ (redμ area,μ beforeμ
implementation)μthatμexistingμBaseμStationμcannotμbeμcoveredμ(orangeμarea).μ
Figureμ2=μSmallμCellμcanμcoverμtrafficμoverflowμwithμexistingμbaseμstationμatμwhereμaμlargeμnumberμofμcommunicationμ
peopleμarea.μ
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Figureμ1:μSmallμCell’sμroleμcase1μ
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Figureμ2:μSmallμCell’sμroleμcase2μ
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Feature of Small Cell SmallμCellμtoμrepresentμitsμname,μsmallμandμeasyμtoμinstall,μasμcomparedμtoμtheμexistingμBaseμStation,μ μ
itμcanμbeμintroducedμatμlowμcostμwhichμisμtheμgreatestμmerit.μ
SmallμCell,μasμshownμinμTableμ1,μisμclassifiedμintoμ4μmajorμcategories.μAnμindividualμdifferenceμbyμ μ userμcapacityμ μ
coverageμareaμ μ transmissionμpowerμoutputμ μ installationμenvironment,μitμdoesμnotμmeanμitμisμstrictlyμdefined.μ
Tableμ1:μtypeμofμSmallμCellμ
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AndμasμshownμinμFigureμ3,μforμfutureμtrafficμgrowth,μinμorderμtoμeffectivelyμutilizeμtheμlimitedμfrequencyμspectrum,μ μ
LTEμ communicationμ schemeμ isμ graduallyμ evolvedμ fromμ FDDμ toμ TDD.μ Inμ thatμ case,μ theμ requiredμ accurateμ timeμ
synchronizationμisμdefinedμasμbelowμ1.5 μsecμaccuracy.μ
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(ULμ=μUpμLink,μDLμ=μDownμlink)μ μ
Figureμ3:μdifferenceμFDDμandμTDDμ
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Requirement high accuracy clock AsμmentionedμinμSectionμ2,μifμtheμTDDμschemeμisμemployed,μinμorderμtoμimproveμtheμreceptionμqualityμofμtheμterminalμ
wouldμrequireμaccurateμ“Frequencyμsynchronization”μandμ“Timeμsynchronization”μbetweenμaμBaseμStationμandμSmallμ
Cell.μItμshowsμtheμimageμinμFigureμ4.μ
- Frequencyμsynchronizationμ=μadjustμcarrierμfrequencyμatμppbμlevel. Airμinterface μ
- Timeμsynchronizationμ=μtimeμdifferenceμisμadjustedμwithinμ1.5μuSμbetweenμBTSμandμSmallμCell. TimeμAccuracy μ
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Figureμ4:μFrequencyμandμTimeμsynchronizationμ
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Critical factor of timing devices Asμelementsμrequiredμforμtheμtimingμdeviceμwhichμgeneratesμaμreferenceμclockμforμstabilizingμbothμofμfrequencyμandμ
timeμsynchronization,μtheμfollowingμthreeμfactorsμareμquiteμimportant.μ
Phase Noise
Frequency Stability = Holdover
Wander Performance
Below,μweμdescribeμtheμdetailsμofμtheseμthreeμfactors.μ
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Phase Noise
PhaseμNoiseμisμnoiseμlevelμthatμnominalμcarrierμfrequencyμpowerμvsμnoiseμpowerμatμeachμoffsetμfrequency.μ
Alsoμreferμto:μhttp://www5.epsondevice.com/en/information/technical_info/pdf/techl_notes_jitter0416.pdfμ
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TheμleftμfigureμinμFigureμ5μisμshowsμtheμPhaseμNoiseμinμtheμgraph.μRightμfigure,μtheμPhaseμNoiseμqualityμhasμ μ
closeμrelationμforμwirelessμsignalμEVMμ(ErrorμVectorμMagnitude).μ
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Figureμ5:μphaseμnoiseμ
Frequency Stability = Holdover
Thereμareμsomeμindicatorsμinμfrequencyμstability,μalthoughμinμtheμSmallμCell,μHoldoverμisμtheμmostμimportant.μ
TheμHoldoverμmeans,μitμisμaμconditionμthatμisμoperatedμbyμstoredμdataμwhichμhasμbeenμretainedμforμtheμphaseμcontrolμ
inμtheμlockμmodeμwhenμclockμsupplyμdeviceμisμlostμtheμreferenceμtimingμinputsμforμtheμcontrolμrefers.μ
TheμleftμfigureμinμFigureμ6μtoμshowμtheμspecificμmeaningμofμtheμHoldover.μAnd,μitμshowsμaμlistμofμHoldoverμstandardμforμ
eachμhierarchyμinμtheμfigureμright.μSmallμCellμisμgenerallyμclassifiedμintoμStratum3.μ
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Figureμ6:μHoldoverμ
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Wander Performance
Wanderμisμaμfluctuationμofμveryμslowμwaveform.μGenerally,μtheμcaseμinμwhichμfluctuatesμtheμfrequencyμinμtheμlongμ
periodμofμmoreμthanμoneμsecondμisμcalledμWander,μitμisμreferredμtoμasμaμJitterμwhenμshakenμtheμfrequencyμinμaμshortμ
periodμofμlessμthanμ0.1μseconds.μ
Alsoμreferμto:μhttp://www5.epsondevice.com/en/information/technical_info/pdf/techl_notes_jitter0416.pdfμ
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Figureμ7:μWanderμ
AsμanμevaluationμindexμofμWanda,μthereμisμaμTIEμandμMTIE,μTDEV.μ
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Features of EPSON timing devices EPSONμprovideμbestμandμoptimumμperformanceμproductsμ forμbelowμ3μ importantμ factorsμbasedμonμownμexclusiveμ
technology.μ
Improving Phase Noise
·μ Theμuniqueμstructuralμdesign,μwasμparticularlyμachieveμgoodμnoiseμcharacteristicsμtoμexternalμinfluencesμ μ μ
μ (temperatureμchangeμdueμtoμtheμflowμofμair).μSeeμFigureμ8.μ
Improving Frequency Stability = Holdover
·μ Anμin-houseμICμdesignμandμmanufacture,μtheμoptimalμcombinationμofμtheμresonatorμelementμaccordingμtoμitsμownμ μ
μ photo-lithographyμtechnique,μtoμachieveμaμgoodμstability.μSeeμFigureμ9.μ
Improving Wander performance
·μ Theμuniqueμstructuralμdesign,μwasμparticularlyμachieveμgoodμwanderμcharacteristicsμtoμexternalμinfluencesμ μ
μ (temperatureμchangeμdueμtoμtheμflowμofμair).μSeeμFigureμ10.μ
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Figureμ8:μEPSON’sμPhaseμNoiseμ
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μFigureμ9:μEPSON’sμstabilityμ
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μFigureμ10:μEPSON’sμWanderμPerformanceμ
EPSON’s products lineup Weμintroduceμaμtimingμdeviceμline-upμofμEPSONμwithμtheμfeaturesμofμmoreμthanμbelow.μ
Fromμtheμfollowingμwebμpagesμlinking,μitμisμpleasedμifμyouμcanμconfirmμdetailedμproductμspecifications.μ
http://www5.epsondevice.com/en/products/tcxo_network/μ
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