lte and nb-iot - robertoverdone.org · how does the specifications look like? ts 36.211 –...
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RadioNetworks,DEI,AlmaMaterStudiorum-UniversitàdiBologna
TelecomItaliaMobileS.p.a.-TIM
LucaFeltrin
LTEandNB-IoT
Ø 3GPPandLTESpecificationsØ LTE
o Architectureo PHYLayero Procedures
Ø NB-IoT
Index
Ø 3GPPandLTESpecificationsØ LTE
o Architectureo PHYLayero Procedures
Ø NB-IoT
Index
Ø 3°GenerationPartnershipProject(3GPP)Ø «Unites7telecommunicationsstandarddevelopmentorganizationsandprovidestheirmemberswith[…]ReportsandSpecificationsthatdefine3GPPtechnologies»
Ø 3TechnicalSpecificationGroups(TSG)o RAN(RadioAccessNetwork),SA(ServicesandSystemsAspects),
CT(CoreNetwork&Terminals)
Ø EachTSGdividedinWorkingGroups(WG)
Whatis3GPP?
Ø Thestandardismadeofmanydocuments:TechnicalSpecifications(TS)andTechnicalReports(TR)
Ø Morethan280documentsinSeries36o Onaverage100pagesperdocument
Ø Alldocumentsarepublic!http://www.3gpp.org/DynaReport/36211.htm
HowdoestheSpecificationslooklike?
TS36.211–PhysicalChannelsandModulation
• TechnicalSpecification(TS)• TechnicalReport(TR)
Series• CODECS• Security• LTE(Series36)• …
Category• PHYLayer• MACLayer• NetworkArchitecture• …
SpecificDocument
Title
Ø 4TechnicalMeetingsperyearo Discussionofthemodificationtothespecifications
Ø Atomicmodificationsofthestandards(1ormoredocuments)areorganizedinChangeRequests(CR)o IftheCRisapprovedanewversionofthedocumentsiscreated
Ø ManyCRtargetingasetofmilestonesaregroupedin«Releases»
Thestandardizationprocess
3GPPRelease 8 9 10 11 12 13 14
LaunchableLTE
BucketListItems
Improvements(Regulatory,
etc.)
CarrierAggregation,CoMP,LIPA,M2M,etc…
Improved
Performance
CarrierAggr.Improvements
IMS,roaming,
P2P,etc.
WiFi,SmallCellImpr.
Signalingopt.SON,MDT,adv.Receiver
MIMOImprov.
D2D,ProSe3D/FD-MIMOIndoorPos.LatencyReduction
NB-IoT
MissionCritical
Enhancem.
V2xservices
Inter-bandCA
Releaseyear 2008 2009 2012 2013 2015 2016 2017
3GPPreleasesevolution
PeakThroughput
DL 300Mbps
UL 75Mbps
PeakSpectrumEfficiency[bps/Hz]
DL 15
UL 3,75
PeakThroughput
DL 1Gbps
UL 500Mbps
PeakSpectrumEfficiency[bps/Hz]
DL 30
UL 15
Today
3GPPreleasesevolution
4G3G
3GPPRelease 8 9 10 11 12 13 14
LaunchableLTE
BucketListItems
Improvements(Regulatory,
etc.)
CarrierAggregation,CoMP,LIPA,M2M,etc…
Improved
Performance
CarrierAggr.Improvements
IMS,roaming,
P2P,etc.
WiFi,SmallCellImpr.
Signalingopt.SON,MDT,adv.Receiver
MIMOImprov.
D2D,ProSe3D/FD-MIMOIndoorPos.LatencyReduction
NB-IoT
MissionCritical
Enhancem.
V2xservices
Inter-bandCA
Releaseyear 2008 2009 2012 2013 2015 2016 2017
Today
Ø 3GPPandLTESpecificationsØ LTE
o Architectureo PHYLayero Procedures
Ø NB-IoT
Index
Architecture
eNB
MME / S-GW MME / S-GW
eNB
eNB
S1 S1
S1 S1
X2
X2X2
E-UTRAN
EPC (evolved Packet Core)
Uu
evolvedNodeB• Sendsandreceivesradio
transmissions• Controlslow-leveloperationof
UE
UserEquipment
UE
UsedforsignalingandhandoverAirInterface
HSSS6a
HomeSubscriberServer• NetworkOperator’s
Subscribers
MobilityManagementEntity• High-leveloperationsofUE
Frequency/TimeDivisionDuplexing
𝑓Uplink Downlink
𝑡
UL/DL
FD-FDD
HD-FDD
TDD
UEtransmits UEreceives
UEtransmits
UEreceives
UEreceives
UEtransmits
UEiscapableofTXandRXatthesametime
UEswitchesfromTXtoRXmodeusingadifferentband
UEswitchesfromTXtoRXmodeusingthesameband
Ø InItaly:o Band03–FDD–75MHz-(3,TIM,Vodafone)o Band07–FDD–70MHz-(Wind,3,TIM)o Band20–FDD–30MHz-(Wind,TIM,Vodafone)
Ø Dividedinchannelsfrom1.4to20MHzo Frequencyreuse
WirelessSpectrum
Source:https://www.frequencycheck.com
Ø Capacityisasimptoticallyproportionalto 𝐦𝐢𝐧�(𝒏↓𝒕 , 𝒏↓𝒓 ) o ImprovedThroughput
Ø DirectivityandDiversityGain
Ø PossibleConfigurationso SISO–SingleInputSingleOutputo MIMO2x2–MultipleInputMultipleOutputo MIMO4x4–MultipleInputMultipleOutput
MIMO
TX RX TX RXTX RX
Ø Multi-carriermodulationo Effectiveagainstselectivefading
OFDMA(Downlink)
Modulator S/P IFFT Cyclicextension
{𝑏↓𝑖 }↓1↑𝑁𝑙 {𝑎↓𝑖 }↓1↑𝑁
Bitstotransmit
𝑥(𝑡)
Ø Multi-carriermodulationo Effectiveagainstselectivefading
OFDMA(Downlink)
Modulator S/P IFFT Cyclicextension
{𝑏↓𝑖 }↓1↑𝑁𝑙 {𝑎↓𝑖 }↓1↑𝑁
Themodulatorcreateasymbolevery𝑙bits
𝑥(𝑡)
Ø Multi-carriermodulationo Effectiveagainstselectivefading
OFDMA(Downlink)
Modulator S/P IFFT Cyclicextension
{𝑏↓𝑖 }↓1↑𝑁𝑙 {𝑎↓𝑖 }↓1↑𝑁
Nsymbolsaresplitinparallelflowswithalowersymbolrate(1/
𝑁)
𝑥(𝑡)
Ø Multi-carriermodulationo Effectiveagainstselectivefading
OFDMA(Downlink)
Modulator S/P IFFT Cyclicextension
{𝑏↓𝑖 }↓1↑𝑁𝑙 {𝑎↓𝑖 }↓1↑𝑁
TheInverseDiscreteFourierTransformisapplied.If𝑁= 2↑𝑘 theIDFTcanbe
optimizedwiththeFastFourierTransform.
𝑁∈{128, 256, 512, 1024, 2048}
𝑥(𝑡)
Ø Multi-carriermodulationo Effectiveagainstselectivefading
OFDMA(Downlink)
Modulator S/P IFFT Cyclicextension
{𝑏↓𝑖 }↓1↑𝑁𝑙 {𝑎↓𝑖 }↓1↑𝑁 𝑥(𝑡)
Acyclicprefix(CP)isaddedtoavoidinter-symbolinterference
SymbolCP
Ø Exampleo ChannelBW=5MHzo Samplingfrequency: 𝑓↓𝑠 =7.68 𝑀𝐻𝑧
OFDMA(Downlink)
ModulatorQPSK S/P
IFFT𝑁=512
Cyclicextension
S/P
Leftemptyforguardband
Leftemptyforguardband
User1
Modulator64-QAMUserN
…
……
…
512subcarriers(211guardband,301fordata)
Symbolsignalmadeof512samples
Symboltime: 𝑇↓𝑢 =512×𝑇↓𝑠 = 512/𝑓↓𝑠 =66.7 𝜇𝑠SubcarrierSpacing:Δ𝑓= 𝑓↓𝑠 /512 =15 𝑘𝐻𝑧
Ø ContiguousspectrumisallocatedforeachuserØ SamenumerologyasOFDMA
SC-FDMA(Uplink)
IFFT CyclicextensionFFTModulatorData
Setofallocatedsubcarriers
Symbol
ReferenceSymbol
Ø 7OFDM/SC-FDMAsymbols(+CyclicPrefixes)makeaSlot
Ø 2SlotsmakeaSubframeo 2×0.5 𝑚𝑠=1 𝑚𝑠
Ø 10SubframesmakeaFrameo 10×1 𝑚𝑠=10 𝑚𝑠o SystemFrameNumber(SFN)->incrementalindex[0,1023]
Ø 1024FramesmakeaHyperframeo 1024×10 𝑚𝑠=10.24 𝑠o HyperFrameNumber(HFN)->incrementalindex[0,1023]o HFNresetsevery1024×10.24 𝑠=2.91 ℎ𝑜𝑢𝑟𝑠
Thetimeaxis
1CP 2CP 3CP 4CP 5CP 6CP0CP
66.7 𝜇𝑠4.7𝜇𝑠5.2 𝜇𝑠
Slot(0.5 𝑚𝑠)
ResourceGridandRE
ResourceElement(RE)• 1subcarrierx1symbol• 1modulatedsymbol• (e.g:64-QAM->6bit)
SF->
Ø PhysicalResourceBlock(PRB)o SmallestResourceassignedbyeNBSchedulero 12subcarriersx1slot(180kHzx0.5ms)
ResourceUnits
SF->
Ø PhysicalResourceBlock(PRB)o SmallestResourceassignedbyeNBSchedulero 12subcarriersx1slot(180kHzx0.5ms)
ResourceUnits
PRB12×7=84 𝑅𝐸𝑠
SF->