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->