nb-iot mobile radio networks - roberto verdone

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Prof. Roberto Verdone www.robertoverdone.org Mobile Radio Networks NB-IOT NB-IOT Roberto Verdone www.robertoverdone.org

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Prof. Roberto Verdone www.robertoverdone.org

Mobile Radio Networks NB-IOT

NB-IOT

Roberto Verdone www.robertoverdone.org

Prof. Roberto Verdone www.robertoverdone.org

Ø  Generalrequirementssetby3GPP:o  Coverage:Morethan20dBimprovementfromGPRS(164dB)o  Throughput:Morethan160bpso  Latency:Lessthan10secondso  BatteryLife:Morethan10years(5Whbattery@MCL=164dB)o  Deployment:OnlySWupdateo  Capacity:Morethan52500devicespercell

LongRangeLowPowerTechnologies

Prof. Roberto Verdone www.robertoverdone.org

LPWANTechnologiesLPWAN

Technologies

ISMBand CellularBand

LTE Cat.0 3GPP: Rel. 12

LTE-M3GPP:Rel.13

NB-IOT3GPP:Rel.13

LoRa

SigFox

RPMAIngenu Weightles

s

EC-GSM-IoT

Prof. Roberto Verdone www.robertoverdone.org

Ø  NB-IOT:anewclassofLTEdeviceso  EnhancedCoverage->Narrowbando  Reducedenergyconsumptiono  Reducedcost/complexity

Ø  Deploymentoptions

LTEGSM

InBand Guard-BandStand-Alone

LTE

1PRB=180kHz

NB-IOTOverview

Prof. Roberto Verdone www.robertoverdone.org

Ø  3CoverageClasses(Normal,Robust,Extreme)Ø  RSSIMeasurementØ  DecisionBasedonThresholds

CoverageClasses

ExtremeRobust

Normal

Prof. Roberto Verdone www.robertoverdone.org

Ø  NarrowBandtransmissiono  LessNoise

Ø  TimeDiversity(TxRepetitions)

o  Differentscramblingcodesoftxtocombine

Ø  BPSKandQPSKModulationschemesØ  HARQØ  ULPowerControl

NoiseFloorWideBand

NarrowBandSamePower

BetterSNR

0 1 2 3

HowtoachieveLongRange?

Prof. Roberto Verdone www.robertoverdone.org

Ø  PowerSavingMode(PSM)o  UEconnectedtoNWbutunreachable

Ø  eDRX(enhancedDiscontinuousReception)

HowtoconsumeLowPower?

Prof. Roberto Verdone www.robertoverdone.org

Ø  ContentionbasedØ  PseudorandomfrequencyhoppingØ  AcollisionhappensiftwoUEstransmitpreamblefromthesame

subcarriero  AttheendoftheRandomAccessProcedure(Msg4)onedevicewillreceivetheUL

Grant,theotherswillfailØ  Preambleisrepeatedseveraltimes

PhysicalLayer-NPRACH

𝑆↓𝑁𝑃𝑅𝐴𝐶𝐻 Sub

carriers

Rep.1 Rep.2 Rep.3 Rep. 𝑃↓𝑁𝑃𝑅𝐴𝐶

𝐻 

User1User3

User2

Prof. Roberto Verdone www.robertoverdone.org

Ø  1 NPRACH definition per Coverage Class Ø  Remaining resources are used by NPUSCH

Ø  BPSK or QPSK (from 96 to 288 bit per RU)

PhysicalLayer-Uplink

Prof. Roberto Verdone www.robertoverdone.org

Ø  NPBCH(BroadcastChannel):Carriesbroadcastmessages(MIB)Ø  NPDCCH(ControlChannel):CarriesUL/DLGrants(NCCE)Ø  NPDSCH(SharedChannel):CarriesDataandotherbroadcast

information(SIB1,SIB2,…)

PhysicalLayer-Downlink

Prof. Roberto Verdone www.robertoverdone.org

NB-IoTDevicesfeatures(e.g.U-blox)Ø  Numericalvalues:

o  LinkBudget:164dBo  Throughput:Peakdatarateof~250kbps,bettersuitedfor50kbpsuse

caseso  Latency:Lessthan10secondso  TransmitCurrent:~220mAat23dBmand100mAat13dBmo  ReceiveCurrent:~40mAo  Synchronization:Itmaintainessynchronousconnectionwiththecellular

networko  ChipsetSize:~3cm2,ModuleSize:~1.6x2.6cmo  Deployment:OnlySWupdateo  Capacity:Morethan52500devicespercello  CostHW:lessthan$10

Prof. Roberto Verdone www.robertoverdone.org

NB-IoTvsLoRaLoRa NB-IoT

Ecosystem LoRa Alliance 3GPP and GSMA

Modulation Proprietary standard by Semtech, based on Chirp Spread Spectrum

DL: OFDMA (15 kHz) UL: SC-FDMA (3.75 or 15 kHz) with BPSK or QPSK

Deployment ISM Bands (433, 868, 2400 MHz)

In-band & Guard band LTE, standalone

Coverage (@MCL) 155-170 dB, dep. regulation 164 dB

Data rate ~293 bps-50 kbps ~250 kbps in 2.4GHz band

UL: > 50 kbps, multi-tone DL: > 50 kbps-250 kbps

Power class (max) 14 dBm 23 dBm

Current consumption Max 84 mA in Tx Max 220 mA in Tx

Protocol Asynchronous Synchronous with eNB Duplexing HD with FDD HD with FDD