Under the umbrella of 3GPP, radio-access technologies for mobile broadband have evolved effectively to provide connectivity to billions of subscribers and things. Within this ecosystem, the standardization of a radio technology for massive MTC applications – narrowband IoT (NB-IoT) – is also evolving. The aim is for this technology to provide cost-effective connectivity to billions of IoT devices, supporting low power consumption, the use of low-cost devices, and provision of excellent coverage – all rolled out as software on top of existing LTE infrastructure. The design of NB-IoT mimics that of LTE, facilitating radio network evolution and efficient coexistence with MBB, reducing time to market, and reaping the benefits of standardization and economies of scale. The IoT embeds a broad range of MTC applications, and among the different types, massive MTC – including applications like smart metering, agriculture and real estate monitoring – sets a number of performance targets for connectivity. Attempting to meet these IoT targets using a radio-access technology designed for mobile broadband, however, doesn't make economic sense. Networks that provide connectivity to massive MTC applications need a radio-access technology that can deliver widespread coverage and low power consumption, often in signal-challenged locations. Hence the need for narrowband-IoT (NB-IoT). NB-IoT is a 3GPP radio-access technology designed to meet the connectivity requirements for massive MTC applications, as well as the design targets for IoT including low device cost, extended coverage, 40 devices per household, long battery life, and uplink latency of under 10 seconds. NB-IoT enjoys all the benefits of licensed spectrum, the feature richness of EPC, and the overall ecosystem spread of 3GPP. At the same time, NB-IoT has been designed to meet the challenging TCO structure of the IoT market. This articles reveals how NB-IoT is being designed and how it can be deployed in GSM spectrum, within an LTE carrier, or in an LTE or WCDMA guard band.

1. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 1
ERICSSON
TECHNOLOGY
GSM
LTE LTE
LTE
Standalone
200kHz
200kHz
200kHz
In-band
Guard band
C H A R T I N G T H E F U T U R E O F I N N O V A T I O N V O L U M E 9 3 | # 3 ∙ 2 0 1 6
NB-IOT:ASUSTAINABLE
TECHNOLOGYFOR
CONNECTING
BILLIONSOFDEVICES

2. ✱ STANDARDIZING NARROWBAND IoT
2 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
SARA LANDSTRÖM
JOAKIM BERGSTRÖM
ERIK WESTERBERG
DAVID HAMMARWALL
Under the umbrella of 3GPP, radio-access technologies for mobile broadband
have evolved effectively to provide connectivity to billions of subscribers and
things. Within this ecosystem, the standardization of a radio technology for
massive MTC applications – narrowband IoT (NB-IoT) – is also evolving. The
aim is for this technology to provide cost-effective connectivity to billions of
IoT devices, supporting low power consumption, the use of low-cost devices,
and provision of excellent coverage – all rolled out as software on top of
existing LTE infrastructure. The design of NB-IoT mimics that of LTE, facilitating
radio network evolution and efficient coexistence with MBB, reducing time to
market, and reaping the benefits of standardization and economies of scale.
t h e b e s t way to provide MTC applications
with cost-effective connectivity is to design
the radio-access network accordingly.
What is needed is a radio-access network
that minimizes battery usage, covers a wide
area, and functions with simplified low-cost
devices while efficiently matching the varying
spectrum allocations of operators. 3GPP
release 13 specifications includes the NB-IoT
feature, with a large degree of deployment
flexibility to maximize migration possibilities
and allow the technology to be deployed in GSM
spectrum, in an LTE carrier, or in a WCDMA or
LTE guard band.
TheIoT embedsabroadrangeofMTC applications,
andamongthedifferenttypes,itiswidelyaccepted
thatmassiveMTC willbethefirsttotakeoff.This
segmentincludesapplicationslikesmartmetering,
agricultureandrealestatemonitoring,aswellas
varioustypesoftrackingandfleetmanagement.
Oftenreferredtoaslowpowerwidearea(LPWA),
networksthatprovideconnectivitytomassiveMTC
applicationsrequirearadio-accesstechnologythat
candeliverwidespreadcoverage,capacity,andlow
powerconsumption.
MassiveMTC devicestypicallysendsmall
amountsofdata,andtendtobeplacedinsignal-
challengedlocationslikebasementsandremote
ruralareas.Duetothesheernumbersofdevices
A SUSTAINABLE TECHNOLOGY FOR
CONNECTING BILLIONS OF DEVICES
NB-IoT:

3. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 3
deployedintypicalscenarios,per-deviceand
life-cyclecostsneedtobekepttoaminimum,
andmeasuresthatpromotebatterylongevityare
essentialforensuringtheoverallcost-effectiveness
ofthesystem.
Thecoverageandthroughputneedsformassive
MTC applicationsarequitedifferentfromthose
ofMBB.Theneedtosupporthighbitrates,for
example,appliestoMBB scenarios,butseldomto
massiveMTC.TheprecisenatureofmassiveMTC
allowsforasignificantdegreeofoptimizationinthe
designofradioaccess.
StandardizationofNB-IoT beganin2014with
a3GPP study.Theobjectiveofthisstudywasto
determinetherequirementsformassiveMTC,
tochooseanevaluationmethodology,andto
investigatewhetherproposedradio-accessdesigns
couldmeetthesetrequirements.Thisstudyled
toworkonthespecificationofNB-IoT [1],witha
numberofdesigntargets–asillustrated
inFigure1.
Inadditiontothedesigntargets,extensive
deploymentflexibilityanduseofindustry
competencetomeettime-to-marketrequirements
Terms and abbreviations
CS–circuit-switched | DL–downlink | DRX–discontinuous reception | eDRX–extended DRX | eMBMS–evolved
multimedia broadcast multicast service | eMTC–enhanced machine-type communications | EPC–Evolved Packet Core
| E-UTRA–Evolved Universal Terrestrial Radio Access | IoT–Internet of Things | LPWA–low power wide area | MAC–
media/medium access control | MBB–mobile broadband | MTC–machine-type communications | NB-IoT–narrowband
Internet of Things | OFDMA–Orthogonal Frequency-Division Multiple Access | PA–power amplifier | PRB–physical
resource block | PSM–power save mode | RF–radio frequency | RLC–Radio Link Control | RRC–Radio Resource
Control | SC-FDMA–single-carrier frequency-division multiple access | TCO–total cost of ownership | UE–user
equipment | UL–uplink
Low device cost:
under USD 5 per module
Long battery life:
more than 10 years
Capacity:
40 devices per household
Extended coverage:
20dB better than GPRS
Report uplink latency:
less than 10 seconds
Figure 1:
IoT design targets

4. ✱ STANDARDIZING NARROWBAND IoT
4 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
havebeenincludedaskeyconsiderationsinthe
specificationofNB-IoT.Tofuture-proofthe
technology,itsdesignexploitssynergieswithLTE
byreusingthehigherlayers(RLC,MAC,and
RRC),forexample,andbyaligningnumerology(the
foundationofthephysicallayer)inboththeuplink
anddownlink.However,theaccessproceduresand
controlchannelsforNB-IoT arenew.
PriortoNB-IoTspecification,workhadalready
begunonthedesignofanotherradioaccess
formassiveMTC tosupportCat-M1 – anew
UE category.Withcompletionalsotargetedfor
release 13,theresultingstandardizationworkitem–
eMTC –coversbitrates,forexample,rangingfrom
hundredsofkbpsto1Mbps.Theserequirementsare
broaderthanNB-IoT, which hasbeenstreamlined
forapplicationswithwidelyvaryingdeployment
characteristics,lowerdatarates,andoperationwith
simplifiedlow-costdevices.
Withacarrierbandwidthofjust200kHz(the
equivalentofaGSMcarrier),anNB-IoTcarriercan
bedeployedwithinanLTEcarrier,orinanLTEor
WCDMAguardband*.ThelinkbudgetofNB-IoT
hasa20dBimprovementoverLTEAdvanced.Inthe
uplink,thespecificationofNB-IoTallowsformany
devicestosendsmallamountsofdatainparallel.
Release13notonlyincludesstandardsforeMTC
andNB-IoT,italsocontainsimportantrefinements,
suchasextendeddiscontinuousreception(eDRX)
andpowersavemode(PSM).PSM wascompleted
inrelease12toensurebatterylongevity,andis
complementedbyeDRX forusecasesinvolving
devicesthatneedtoreceivedatamorefrequently.
Deploymentflexibilityand
migrationscenarios
As a finite and scarce natural resource, spectrum
needs to be used as efficiently as possible.
And so technologies that use spectrum tend
to be designed to minimize usage. To achieve
spectrum efficiency, NB-IoT has been designed
with a number of deployment options for GSM,
WCDMA, or LTE spectrum, which are illustrated
in Figure 2.
〉〉 standalone–replacingaGSMcarrierwithanNB-IoT
carrier
〉〉 in-band–throughflexibleuseofpartofanLTEcarrier
〉〉 guardband–eitherinWCDMAorLTE
Starting with standalone
Thestandalonedeploymentisagoodoptionfor
WCDMA orLTE networksrunninginparallelwith
GSM
LTE LTE
LTE
Standalone
200kHz
200kHz
200kHz
In-band
Guard band
Figure 2:
Spectrum usage
deployment options
*Guard band is a thin band
of spectrum between
radio bands that is used to
prevent interference.

5. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 5
GSM.BysteeringsomeGSM/GPRS traffictothe
WCDMA orLTE network,oneormoreoftheGSM
carrierscanbeusedtocarryIoT traffic.AsGSM
operatesmainlyinthe900MHz and1,800MHz
bands(spectrumthatispresentinallmarkets),this
approachacceleratestimetomarket,andmaximizes
thebenefitsofaglobal-scaleinfrastructure.
Migrationtoin-band
Whenthetimingisright,GSM spectrumwill
berefarmedforusebymoredemandingMBB
traffic.RefarmingspectrumforusebyLTE is
astraightforwardprocess,evenwhenNB-IoT
carriersexistintheGSM spectrumbecause
refarmingdoesnotimpactNB-IoT devices,andany
NB-IoT carriersinGSM willcontinuetooperate
withintheLTE carrieraftermigration.Sucha
future-proofsetupispossible,asthestandaloneand
in-bandmodesusethesamenumerologyasLTE,
andRF requirementsaresettomatchthedifferent
deployments,soalldevicesareguaranteedto
supportin-bandoperationatthetimeofmigration.
In-band:bestoptionforLTE
ForoperatorswithmainlyLTE spectrumavailable,
theLTE in-bandoptionprovidesthemost
spectrum-andcost-efficientdeploymentofNB-IoT.
Morethananythingelse,thisparticularoptionsets
NB-IoT apartfromanyotherLPWA technology.
AnNB-IoT carrierisaself-containednetwork
elementthatusesasinglephysicalresourceblock
(PRB).Forin-banddeploymentswithnoIoT traffic
present,thePRB canbeusedbyLTE forother
purposes,astheinfrastructureandspectrumusage
ofLTE andNB-IoT arefullyintegrated.Thebase
stationschedulermultiplexesNB-IoT andLTE
trafficontothesamespectrum,whichminimizesthe
totalcostofoperationforMTC, which essentially
scaleswiththevolumeofMTC traffic.Intermsof
capacity,thecapabilityofasingleNB-IoT carrier
isquitesignificant–evaluationshaveshownthat
astandarddeploymentcansupportadeployment
densityof200,000NB-IoT deviceswithinacell–for
anactivitylevelcorrespondingtocommonusecases.
Naturally,moreNB-IoT carrierscanbeaddedif
morecapacityisneeded.
Usingguardbandspectrum
AthirdalternativeistodeployNB-IoT inaguard
band,andhere,thefocusisontheuseofsuchbands
inLTE.Tooperateinaguardbandwithoutcausing
interference,NB-IoT andLTE needtocoexist.In
contrasttootherLPWA technologies,thephysical
NB-IoT layershavebeendesignedwiththe
requirementsofin-LTE-guard-bandcoexistence
specificallytakenintoconsideration.Again,like
LTE,NB-IoT usesOFDMA inthedownlinkand
SC-FDMA intheuplink.
ThedesignofNB-IoT hasfullyadoptedLTE
numerology,using15kHz subcarriersintheuplink
anddownlink,withanadditionaloptionfor3.75kHz
subcarriersintheuplinktoprovidecapacityin
signal-strength-limitedscenarios.
Longrangeandlongbatterylife
Thegeographicalareaforwhichamobilenetwork
canprovidecoveragedependsonsitedensityand
linkbudget.ComparedwithGPRS,WCDMA and
LTE,thelinkbudgetofNB-IoT hasa20dBmargin,
andusecasestendtooperatewithlowerdatarates.
So,notonlycanNB-IoT reusetheGSM,
WCDMA,orLTE grid,theimprovedlinkbudget
enablesittoreachIoT devicesinsignal-challenged
locationssuchasbasements,tunnels,andremote
ruralareas–placesthatcannotbereachedusingthe
network’svoiceandMBB services.
Intechnicalterms,thecoveragetargetofNB-IoT
hasalinkbudgetof164dB,whereasthecurrent
GPRS linkbudgetis144dB(TR 45.820[2]),andLTE
is142.7dB**(TR 36.888[3]).The20dBimprovement
correspondstoasevenfoldincreaseincoveragearea
foranopenenvironment,orroughlythelossthat
occurswhenasignalpenetratestheouterwallofa
building.Standardizationactivitiesin3GPP have
shownthatNB-IoT meetsthelinkbudgettarget
of164dB,whilesimultaneouslymeetingtheMTC
applicationrequirementsfordatarate,latency,and
batterylife.
ThebatterylifeofanMTC devicedependsto
someextentonthetechnologyusedinthephysical
layerfortransmittingandreceivingdata.However,
longevitydependstoagreaterextentonhow
efficientlyadevicecanutilizevariousidleandsleep
** The noise figure
assumptions in3GPP TS
36.888 [3] used in the link
budget calculations are
more conservative than
in the corresponding link
budget for GSM in 3GPP
TR 45.820. Using the
noise figure assumptions
from TR 45.820, the LTE
link budget becomes
142.7dB.

6. ✱ STANDARDIZING NARROWBAND IoT
6 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
modesthatallowlargepartsofthedevicetobe
powereddownforextendedperiods.TheNB-IoT
specificationaddressesboththephysical-layer
technologyandidlingaspectsofthesystem.
LikeLTE,NB-IoTusestwomainRRCprotocol
states:RRC_idleandRRC_connected.In­­RRC_idle,
devicessavepower,andresourcesthatwouldbeused
tosendmeasurementreportsanduplinkreference
signalsarefreedup.InRRC_connected,devicescan
receiveorsenddatadirectly.
Discontinuousreception(DRX)istheprocess
throughwhichnetworksanddevicesnegotiate
whendevicescansleepandcanbeapplied
inbothRRC_idleandRRC_connected.For
RRC_connected,theapplicationofDRX reduces
thenumberofmeasurementreportsdevicessend
andthenumberoftimesdownlinkcontrolchannels
aremonitored,leadingtobatterysavings.
3GPP release12supportsamaximumDRX cycle
of2.56seconds,whichwillbeextendedto10.24
secondsinrelease13(eDRX).However,anyfurther
lengtheningofthisperiodisasyetnotfeasible,
asitwouldnegativelyimpactanumberofRAN
functionsincludingmobilityandaccuracyofthe
systeminformation.InRRC_idle,devicestrackarea
updatesandlistentopagingmessages.Tosetupa
connectionwithanidledevice,thenetworkpagesit.
Powerconsumptionismuchlowerforidledevices
thanforconnectedones,aslisteningforpagesdoes
notneedtobeperformedasoftenasmonitoringthe
downlinkcontrolchannel.
WhenPSM wasintroducedinrelease12,it
enableddevicesinRRC_idletoenteradeepsleep
inwhichpagesarenotlistenedfor,noraremobility-
relatedmeasurementsperformed.DevicesinPSM
performtrackingareaupdatesafterwhichthey
directlylistenforpagesbeforesleepingagain.PSM
andeDRX complementeachotherandcansupport
batterylifetimesinexcessof10yearsfordifferent
reachabilityrequirements,transmissionfrequencies
ofdifferentapplications,andmobility.
Therangeofsolutionsdesignedtoextendbattery
lifetimesneedtobebalancedagainstrequirements
forreachability,transmissionfrequencyofdifferent
applications,andmobility.Theserelationsare
illustratedinFigure3.
Superior capacity design
Tomeetcapacityrequirements,NB-IoT needsto
multiplexmanydevicessimultaneously,andprovide
connectivityinanefficientmannerforallofthem
irrespectiveofcoveragequality.Asaresult,the
designofNB-IoT supportsarangeofdatarates.
Theachievabledataratedependsonthechannel
quality(signaltonoiseratio),andthequantityof
allocatedresources(bandwidth).Inthedownlink,
alldevicessharethesamepowerbudgetand
severalmaysimultaneouslyreceivebase-station
transmissions.Intheuplink,however,eachdevice
hasitsownpowerbudget,andthiscanbeusedto
advantagebymultiplexingthetrafficgeneratedby
severaldevices,astheircombinedpowerisgreater
thanthatofasingledevice.
Inmanylocations,NB-IoT deviceswillbe
limitedbysignalstrengthratherthantransmission
bandwidth.Suchdevicescanconcentratetheir
transmissionenergytoanarrowerbandwidth
withoutlossofperformance,whichfreesupband-
widthforothers.Thepossibilityofallocatingsmall
amountsofbandwidthtospecificdevicesincreases
systemcapacitywithoutlossofperformance.
Toenablesuchsmallbandwidthallocations,
NB-IoT usestonesorsubcarriersinsteadof
resourceblocks.Thesubcarrierbandwidthfor
NB-IoT is15kHz,comparedwitharesourceblock,
whichhasaneffectivebandwidthof180kHz.Each
deviceisscheduledononeormoresubcarriers
intheuplink,anddevicescanbepackedeven
closertogetherbydecreasingthesubcarrier
spacingto3.75kHz.Doingso,however,resultsin
differingnumerologyforLTE andNB-IoT,and
someresourceswillneedtobeallocatedtoavoid
interferencebetweenthe3.75kHz and15kHz
subcarriersinsteadofutilizingthemfortraffic,which
mayleadtoperformancelosses.
Forscenariosthatincludedevicesinbothgood
andbadcoverageareas,itispossibletoincrease
thedataratebyaddingmorebandwidth.Inthe
uplink,dataratescanbeincreasedupto12times
byallocatingdeviceswithamulti-toneormulti-
subcarrierratherthanasingletone,forexample.
Thisapproachimprovescapacityforscenarios
wheremanydeviceshavegoodcoverage,asdata

7. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 7
10s
30s
1m
3m
5m
10m
30m
1h
3h
6h
12h
24h
2 days
5 days
3 days 5 days 24h 12h 6h 3h 1h 30m 10m 3m 1m
Data inter-arrival time
Reachability interval
PSM
eDRX in RRC_Idle
eDRX in RRC_Connected
Figure 3
Good coverage

8. ✱ STANDARDIZING NARROWBAND IoT
8 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
transfercompletesquickly.Goodcoverageistypical
whenNB-IoT isrolledoutonadensegridand/or
whenmostdevicesarewithintheoriginalLTE cell
coveragearea.
Datarateisasignificantfactorwhentryingto
achievethebestdesignforNB-IoT,asitaffects
bothlatencyandpowerconsumption.Table1shows
theuplinklatencyvaluesforadevicetoconnect
andtransmitdata.Thedataratesforworst-case
coverage(+20dB)arelowerthanthoseforMBB
atthecelledge(0dB),andlatencyincreasesfrom
1.6to7.6seconds.Theuplinkdatarateisthemain
causeofthisdegradation,yetevenforworst-case
scenarios,NB-IoTuplinklatencyisstillunderthe
10-seconddesigntarget.Whenitcomestopower
consumption,thedominatingfactoristhespeedat
whichdevicestransmitdata,whichincreasesinline
withacceleratingdatarates.
NB-IoT hasbeendesignedwithgood
multiplexingandadaptabledataratesandsoitwill
beabletomeetpredictedcapacityrequirements.
Thecapacityrequirementstargetin3GPP TR
45.820[1]hasbeensetto40devicesperhousehold,
basedonassumptionsforLondon,which
correspondto52,500devicespercell.Simulations
showsupportfor200,000devicespercell–four
timesthesettarget.
Deviceaspects
Affordablemodemsareakeyelementoflarge-
scalesensordeployment,sothatprocesses
suchastemperatureorwatermeterreporting
canbeoptimized.Atthesametime,thedata
rateandlatencyrequirementsofsuchsensor-
heavyapplicationstendtoberelativelymodest:
acharacteristicthatcanbeusedtoadvantageto
reducesolutioncomplexity–andcost.
NB-IoT devicessupportreducedpeakphysical
layerdatarates:intherangeof100-200kbpsor
significantlylowerforsingle-tonedevices.To
facilitatelow-complexitydecodingindevices,turbo
codesarereplacedwithconvolutionalcodesfor
downlinktransmissions,andlimitsareplacedon
maximumtransportblocksize–whichis680bitsfor
DL andnotgreaterthan1000bitsforUL.
TheperformancerequirementssetforNB-IoT
makeitpossibletoemployasinglereceiverantenna
(twoareneededforLTE MBB).Asaresult,theradio
andbasebanddemodulatorpartsofthedeviceneed
onlyasinglereceiverchain.ByoperatingNB-IoT
deviceshalfduplexsothattheycannotbescheduled
tosendandreceivedatasimultaneously,theduplex
filterinthedevicecanbereplacedbyasimple
switch,andaonlysinglelocaloscillatorforfrequency
generationisrequired.Theseoptimizationsreduce
costandpowerconsumption.
At200kHz,thebandwidthofNB-IoTis
substantiallynarrowerthanotheraccess
technologies.LTEbandwidths,forexample,range
from1.4MHzto20MHz.Thebenefitofanarrowband
technologyliesinthereducedcomplexityof
analog-to-digital(A/D)anddigital-to-analog(D/A)
conversion,buffering,andchannelestimation–allof
whichbringbenefitsintermsofpowerconsumption.
Table 1:
Maximum uplink latency
for a device on the MBB cell
border (+0dB) and beyond
(+ 10dB and + 20dB)
Duration (ms)
Coverage Sync MIB PRACH RAmsg2-4 ULgrant ULdata Ack ULdata TOTAL
340 151 324 622 48 39 41 39 1,604
340 151 688 708 45 553 47 553 3,085
520 631 1,440 1,060 49 1,923 77 1,923 7,623
+0dB
+10dB
+20dB

9. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 9
NB-IoT bringsaboutasignificantdesignchange
intermsoftheplacementofthedevice'spower
amplifier(PA).Integratingthiselementdirectlyonto
thechip,insteadofitbeinganexternalcomponent,
enablessingle-chipmodemimplementations–
whicharecheaper.
Reuseofexistingtechnology
ThedesignofNB-IoT radioaccessreusesanumber
ofLTE designprinciplesandhasthebackingofthe
traditionalcellular-networkandchipsetvendors
thatmadeMBB asuccess.NB-IoT employsthe
samedesignprinciplesasLTE (E-UTRA),although
itusesaseparatenewcarrier,newchannels,and
randomaccessprocedurestomeetthetarget
requirementsofIoT usecases–suchasimproved
coverage,lowerbatteryconsumptionandoperation
innarrowspectrum.ConstructingNB-IoT inthis
waytakesadvantageofLTE’swell-established
globalreach,economiesofscale,andindustry-
leadingecosystem.
TheNB-IoT downlinkisbasedonOFDMA and
maintainsthesamesubcarrierspacing,OFDM
symbolduration,slotformat,slotduration,and
subframedurationasLTE.Asaresult,NB-IoT can
providebothin-bandandguardbanddeployment
withoutcausinginterferencebetweenitscarriers
andthoseusedbyLTE forMBB,makingNB-IoT
awellintegratedIoTsolutionforLTE-focused
operatorsinadditiontoCat-M1.
Useofthesameupperlayersisyetanother
similaritybetweenLTE andNB-IoT,withsome
optimizationstosupportoperationwithlow-cost
devices.Forexample,asasingletechnologysolution,
NB-IoT doesnotsupportdualconnectivity;and
devicesdonotsupportswitchingbetweenaccess
technologies(GSM,WCDMA,orWi-Fi)inactive
mode.SupportforCS voiceserviceshasalsobeen
removed.Thesescopesavingsresultinamuch
lowerrequirementformemorycapacityforNB-IoT
devicescomparedwitheventhemostrudimentary
MBB LTE ones.
NB-IoT usesanS1-basedconnectionbetween
theradionetworkandtheEPC.Theconnectionto
theEPC providesNB-IoT deviceswithsupportfor
roamingandflexiblecharging,meaningthatdevices
canbeinstalledanywhereandcanfunctionglobally.
Theambitionistoenablecertainclassesofdevices
–likesmokedetectors–tobehandledwithpriority
toensurethatemergency-situationdatacanbe
prioritizedifthenetworkiscongested.
Existing3GPP architectureprovidesaglobal,
highlyautomatedconnectivitymanagementsolution
thatisneededforlarge-scaleIoT deployments.
NB-IoT andLTE usethesameO&Mframework,
runningasasinglenetworkcarryingMBB and
MTC traffic,whichreducesoperationalcostsin
areaslikeprovisioning,monitoring,billing,and
devicemanagement.SimilartopresentLTE
networks,NB-IoT supportsstate-of-the-art3GPP
security,withauthentication,signalingprotection,
anddataencryption.
LTE featuresthatalreadyexist,likecell-ID-based
positioning,arestraightforwardenoughfor
NB-IoT toinherit.ByaligningwithLTE evolution,
NB-IoT couldsupportexistingfeaturesand
DATA RATE IS A
SIGNIFICANT FACTOR
WHEN TRYING TO ACHIEVE THE
BEST DESIGN FOR NB-IOT, AS IT
AFFECTS BOTH LATENCY AND
POWER CONSUMPTION
NB-IoT: the advantages of being part of 3GPP
〉〉useoftheLTEecosystem,leadingtofast
development,economiesofscale,andglobal
roaming
〉〉 canbedeployedasasimpleadditionofnewsoftware
toexistingLTEinfrastructure
〉〉amanagementframeworkexists,enablinglarge-
scaledeployments
〉〉frameworkincludesstate-of-the-artsecurity
〉〉futurefeaturegrowthforMBBandNB-IoTusecases

10. ✱ STANDARDIZING NARROWBAND IoT
10 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
futurefunctionalitydesignedfortheentirecellular
ecosystem,includingMBB aswellasIoT usecases.
ThebroadcastfeatureeMBMS enablesalarge
numberofdevicestobeupdatedsimultaneously,
andthedevice-to-devicecommunicationfeature
thatrelaystransmissionstodevicesinpoorcoverage
areexamplesofsynergies.Inthefuture,thesetwo
featurescanbespecifiedforNB-IoT usingthesame
conceptsandexperiencethatwereusedtodevelop
themforLTE MBB.
Conclusions
NB-IoT isthe3GPP radio-accesstechnology
designedtomeettheconnectivityrequirements
formassiveMTC applications.Incontrasttoother
MTC standards,NB-IoT enjoysallthebenefits
oflicensedspectrum,thefeaturerichnessofEPC,
andtheoverallecosystemspreadof3GPP.Atthe
sametime,NB-IoT hasbeendesignedtomeetthe
challengingTCO structureoftheIoT market,in
termsofdeviceandRAN cost,whichscaleswith
transferreddatavolumes.
ThespecificationforNB-IoT ispartof3GPP
release 13anditincludesanumberofdesigntargets:
devicecostunderUSD 5permodule;acoverage
areathatisseventimesgreaterthanexisting3GPP
technologies;devicebatterylifethatislongerthan
10yearswithsustainedreachability;andmeeta
capacitydensityof40devicesperhousehold.
AsNB-IoT canbedeployedinGSM spectrum,
withinanLTE carrier,orinanLTE orWCDMA
guardband,itprovidesexcellentdeployment
flexibilityrelatedtospectrumallocation,whichin
turnfacilitatesmigration.Operationinlicensed
spectrumensuresthatcapacityandcoverage
performancetargetscanbeguaranteedforthe
lifetimeofadevice,incontrasttotechnologies
thatuseunlicensedspectrum,whichruntherisk
ofuncontrolledinterferenceemergingevenyears
afterdeployment,potentiallyknockingoutlarge
populationsofMTC devices.
Thefirststandarddevelopmentof5G radio
accessiscurrentlyunderway,withsystem
deploymenttargetedfor2020.Inthiscontext,the
abilitytofuture-proofadditionaltechnologieslike
NB-IoT isatoppriority.Intheongoingdiscussions
in3GPP surrounding5G,LTE willcontinuetobe
anintegralpartofradionetworksbeyond2020,and
so,NB-IoT'sresemblancetoLTE safeguardsthe
technologyfromdivergingevolutionpaths.
References
1. 3GPP, December 2015, NB-IoT work item description RP-152284, available at: http://ow.ly/4mQAfx
2. 3GPP, TR 45.820, Cellular system support for ultra-low complexity and low throughput Internet of Things
(CIoT), available at: http://ow.ly/4mQAny
3. 3GPP, TR 36.888, Study on provision of low-cost Machine-Type Communications (MTC) User Equipments
(UEs) based on LTE (v12.0.0), available at: http://ow.ly/4mQAwn

11. STANDARDIZING NARROWBAND IoT ✱
APRIL 22, 2016 ✱ ERICSSON TECHNOLOGY REVIEW 11
Sara Landström
◆ is a strategic product
manager in the area of 4G
and 5G at Ericsson. She
is currently responsible
for the IoT, V2X, and
carrier aggregation radio
portfolios. She joined
Ericsson in 2008 as a
researcher focusing on radio
resource management,
heterogeneous networks,
and radio access for IoT.
Since then she has been
project manager for
various proprietary feature
development projects
and has headed up the
Radio Network Algorithms
research group.
She holds an M.Sc. in
computer engineering
and a Ph.D. in computer
networking, both from
Luleå University of
Technology, Sweden.
Joakim Bergström
◆ is an expert in new radio-
access networks at Design
Unit Radio. He has more
than 15 years of experience
in standardization within
the 3GPP RAN area working
with HSPA, LTE and 5G. He
holds an M.Sc. in electrical
engineering from KTH Royal
Institute of Technology,
Stockholm. Within the radio
area, he has coordinated all
of Ericsson’s standardization
activities and projects since
2011.
Erik Westerberg
◆ joined Ericsson from
MIT, Massachusetts, US, in
1996 and is a senior expert
in system and network
architecture. During his
first 10 years at Ericsson, he
worked with development
of the mobile broadband
systems before broadening
his work to include the full
network architecture as he
served as Chief Network
Architect until 2014. He
holds a Ph.D. in quantum
physics from Stockholm
University, Sweden.
David Hammarwall
◆ is head of Services
and Infrastructure within
Product Area 4G/5G RAN.
A main driver of Ericsson’s
strategy and execution
within the Cellular Internet
of Things, Hammarwall
joined Ericsson’s LTE
product management
team in 2013, with primary
responsibilities for LTE
baseband capacity,
software architecture,
and features developed in
device partnerships.
He received his Ph.D. in
telecommunications from
KTH Royal Institute of
Technology in Stockholm in
2007 before joining Ericsson
Research to focus primarily
on 3GPP standardization.
He has acted as a primary
standardization delegate
in 3GPP, leading Ericsson’s
standardization efforts
and strategy within multi-
antenna technologies,
Coordinated Multipoint, and
small cell enhancements.
theauthors

12. ✱ STANDARDIZING NARROWBAND IoT
12 ERICSSON TECHNOLOGY REVIEW ✱ APRIL 22, 2016
ISSN 0014-0171
284 23-3279 | Uen
© Ericsson AB 2016
Ericsson
SE-164 83 Stockholm, Sweden
Phone: +46 10 719 0000