CAM Technical Paper LTE.pdf

7/30/2019 CAM Technical Paper LTE.pdf

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Introduction

LTEtechnologypromisestobringspeedsofover100Mbpsdownlinkand50Mbpsuplinktomobileusers

usingmobilebroadbandapplications.With196operatorsin75countriescurrentlyinvestinginthe

technology,LTEisnowgenerallyacknowledgedtorepresentthefutureoftheindustry.

Inturn,demandfordataisrunningatlevelsthatwereunimaginableevenacoupleofyearsago.Thisisdue

totheemergenceofsmartphonesandotherhighenddevicesrunningmultimediaapplicationssuchas

streamingvideoandmobileTV.By2015,itispredictedthattotaldatarateswillexceed6,300,000terabytes

permonth.

Giventhatsome50%oftotalmobiletrafficissaidtooriginateorterminatewithinbuildings,wepredicta

corresponding

massive

increase

in

demand

for

data

from

our

in

building

networks.

Thepurposeofthisdocumentistopresentthefiguresrelatingtothisgrowthindatademandandtoassess

howwemayscaleourexistinginbuildingDASnetworkstohandlethisgrowth.Weconsideroptionssuchas

deployingsmallercellstoimprovecapacityinlocalisedareas;utilisingMIMOtechnologiestoofferhigher

datarates;andupgrading,allorpartofourexistingDASnetworkstoLTEtechnology.Thedocumentis

structuredasfollows:

Firstwehighlightthefiguresbehindthehypesurroundingthiseverincreasingdemandfordata.WelookatthenumberofdevicessuchassmartphonesandtabletPCs,bothnowandintheyearstocome,

andmultimediaservicessuchasvideo,VoIP,gamingetc.Thesefigureswillhelpusbenchmarkthe

requirements

of

future

in

building

network

designers.

Workingwiththesefiguresfordatademand,wemustconsidertheperformanceofbothexistingcellulartechnologies(HSPAandHSPA+)andemergingtechnologies(LTEandLTEAdvanced).Weneed

toestimatehowthesetechnologieswillbeabletocopewithincreasingdemandandforhowlong.

OneofthekeyfactorsinincreasingtheperformanceofwirelessnetworksistheintroductionMIMOtechnologies.MIMOwillplayanimportantroleinourdecisionsonfuturenetworkdesign.Asectionin

thisdocumenthasbeendedicatedtoexplainingmultipleantennatechnologies.

WeconsiderhowaninbuildingDASmaybedesignedtocopewiththevolumesofdatathatwillberequired

in

the

coming

months

and

years.

In

the

case

of

4G

networks,

the

challenge

from

the

outset

willbetoengineerthenetworkstodelivercapacity,asopposedtocoverage,whereitisneeded.

FinallywelookatacoupleofpossiblesolutionsformigratingaDAStoLTEwith2x2MIMO,withoneoptionsimplydoublinguponexistinginfrastructureandamorenovelapproachusingCAT5/6cabling

tocarrytheDASsignals.

LTETechnicalChallengesforInBuildingCoverage


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LTETechnicalChallengesforInbuildingCoverage

Copyright:CellularAssetManagementLtd2010 www.cellularasset.com Page2

ThisdocumentisdesignedtohighlightthechallengesinvolvedindesigningaDAStosupportthemassivedatademandsgeneratedbytheproliferationofsmartphonesandthelike,togetherwith

applicationssuchasvideostreamingandmultimediagaming.Itisnottheobjectivetoproposeany

solutionsbuthopefullytostimulatediscussion.

Exponentialgrowth

in

data

consumption

Overtheperiodofthelastthreeyearsto2010,thevolumeofdatabeingconsumedovermobilenetworks

hasalmosttripledyearonyear.In2010,accordingtoCisco,totalglobalmobiledatatrafficwasinexcessof

230petabytespermonth(1petabyte=1,000,000gigabytes).Thisisoverthreetimesgreaterthantotal

globalinternetusageinthewholeoftheyear2000.

Whilstthisrateofgrowthisforecasttoleveloutduring2011,Ciscohasforecastthatby2015wewillseea

26foldincreasein2010rates,withmonthlyusageof6.3exabytespermonth(1exabyte=1,000

petabytes).Pleaseseefigure1below.

Moreover,AlcatelLucenthasforecasta16foldincreaseinmobiledatatrafficto2015butwarnedthatit

couldgrowashighas40timestodayslevels[2].

Figure1:CiscoForecasts6.3Exabytes(6,300,000Terabytes)

perMonthofMobileDataTrafficby2015

Thisdescription

of

the

growth

in

data

rate

consumption

includes

some

newterminologyusedtodescribethevastquantitiesofdataunder

discussion.Thechartoppositeshowsthevaluesofthesenewterms,suchaspetabytesandexabytesrelative

tothemorerecognisablefiguressuchasgigabytes.


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Smartphones,TabletPCsandDataHungryApplications

Thegeneralpatternofacceleratinggrowthinusageofadvanceddataservicesislinkedtoastronguptake

intheusageofsmartphonesandotherhighenddevicessuchasTabletPCsandmobilegamingconsoles.

Smartphones,runningapplicationssuchasstreamingvideoandinteractivegamingareextremelydata

hungry.In

2010,

the

typical

smartphone

generated

24

times

more

mobile

data

traffic

than

abasic

feature

cellphone.CiscoVNI

Tomakemattersworse(forthenetworkdesigner)theiPhoneandtheAndroidbaseddeviceswillconsume

5to10timesasmuchdataasaregularsmartphone.

Typicallyahighendsmartphonewillgeneratearound79MBpermonthcomparedwith3.3MBpermonth

forabasicfeaturesetphone.

Thetablebelowgivesanideaofthelevelsoftrafficgeneratedbydifferentdevicetypes.

Devicetype

Traffic

Generated

cf.

Basic

Mobile

Phone

Basicmobilephone x1

Smartphone x24

Handheldgamingconsole x60

TabletPC x122

Laptop x515

Table1:FiguresCourtesyCiscoVNI2011

ImpactofsmartphonesfromtheMobileOperatorsperspective

FigurescollatedandreleasedbytheGlobalMobileSuppliersAssociation(GSA)showasubstantialgrowthin

revenuethroughout2010whichhasbeendrivenbythesuccessofthesmartphonethroughoutEurope,the

USAandAsiaPacific.

VodafoneUK:2010datarevenuegrowthup30%;drivenbysmartphonesuccess VodafoneItaly:2010datarevenuegrowthup22%;smartphonesales50%oftotalhandsetsales AT&TUSA:2010datarevenuegrowthup27%;7.4milliondevicesales;4.1millioniPhonesalesin2010 PCCWAsia: >80%ofnewsubscribersaresmartphoneusers;3Gdatarevenuegrewby156%inH12010Thisphenomenalgrowthinsmartphoneadoptionandtheexponentialincreaseindatausageisfurther

borneoutbythefollowingfiguresandpredictions:

Googlestatethat300,000Androidphonesareactivatedworldwidedaily. TheITUestimatesthattheglobalnumberofsmartphonesisexpectedtoquadruplefromtoday's(2010)

estimateof200millionhandsetstoalmost1billionby2015.


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Figure2:CourtesyGlobalMobileSuppliersAssociationwww.gsacom.com

AccordingtoInformaTelecoms&Media,whilstsmartphonepenetrationcurrentlyrunsatjust13%,this

accountsfor65%ofallmobilecellulartrafficworldwide.Thisusagefigureissettoincreaseexponentially

overthenextfiveyearswiththeaveragetrafficpersmartphoneuserincreasingby700%by2015.

Inadditiontothesuccessofthesmartphone,therearerangesofother,datahungrydevicesthathave

recentlyemergedonthesceneandarebeingadoptedbytheconsumeratarate:

WorldwidesalesofmediatabletssuchastheiPadwillreach19.5millionbytheendof2010andexceed54millionin2011.Gartner.

Shipmentsofmobilebroadbandenabledconsumerproducts,includingebookreaders,mobiledigitalcameras,camcorders,personalmediaplayersandmobilegamingdeviceswillincrease55foldbetween

2008and2014withtotalshipmentsreaching58millionunitsperyearin2014.ABIResearch

GiventhatatabletPCcangenerateaboutfivetimesasmuchdataasahighendsmartphone,thepotential

data

usage

of

a

combination

of

all

these

devices

is

beyond

any

figure

that

the

original

mobile

networks

weredesignedtohandle.


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PredictionsonFutureDemandforDataonInbuildingSystems

UsingthesefiguresasaguidelinewecanmodelthepotentialimpactonaninbuildingDASoftherapidly

increasingdemandfordatadueto:

Thelevelofpenetration(marketshare)ofsmartphonesincreasingfrom13%currentlyto50%andbeyond

by

2015

Asevenfoldincreaseintrafficpersmartphone:CiscoVNI

Inpredictingthedemandonaninbuildingnetworkwemakethefollowingassumptions:

1. Inaninbuildingscenarioweassumethemajorityofthetrafficwillcomefrommobilephones.Wedonotincludelaptopsorotherdevices.(smartphonetraffic+basicphonetraffic=compositetraffic).

2. Therewillbenosignificantincreaseinthenumberofhandsetswithinagiveninbuildingscenarioasweassumethebuildingpopulationwillnotchangesignificantlyovertime.

3. AlthoughtheDASforeachindividualbuildingwillexperiencedifferenttrafficchangesovertime,wecanassumeapredictionforagenericscenariosuchasashoppingcentre.

Tables2and3showthepredictedtrafficlevelsasdescribedaboveperdevice:

Combiningthefiguresforincreaseinpenetrationofsmartphoneswiththesevenfoldincreaseindata

demandfromthesedevices,wecanseefromthetablesabovethatinbuildingtrafficperdeviceis

predictedtoincreasefrom13.2to278.9MBpermonthby2015,morethanadoublingofdatayearon

year.

Table2:Currenttrafficlevels(MBpermonth)

TrafficperMonth Penetration% TrafficxPenetrationBasicPhone 3.3 87% 2.871

SmartPhone 79.2 13% 10.296

CompositeTraffic 13.167

Table3:Predictedtrafficin2015(MBpermonth)

TrafficperMonth Penetration% TrafficxPenetrationBasicPhone 3.3 50% 1.65

SmartPhone 554.4 50% 277.2

CompositeTraffic 278.85


6/17



Indesigninganinbuildingnetworktodeliverthesevolumesofdatathereareanumberofoptions

availabletous:

DeployingHSPA+andLTEtechnologywithinbuildingstoprovidehighthroughput,lowlatencynetworks.

MIMO

antenna

systems

are

an

integral

part

of

LTE

and

HSPA+

technologies

and

may

be

used

to

improveperformance,byimprovingthequalityoftheradiolink,and/orincreasingdatathroughput,

undergivenconditions.

Smallcellarchitecturescanbeusedtoincreasethecapacityofanetworkbydeliveringthedatalocallytoasmallernumberofusers.

Theseoptionswillbediscussedinthefollowingsections.


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ComparativePerformanceofCellularTechnologies:HSPA,HSPA+andLTE

Asthedemandfordataincreaseswemustconsiderthetechnologiesbeingused(withintheinbuilding

system).Althoughtherearemorecriteriathanjustdataratestoconsiderwhendecidingonacellular

technology,itisoneofthemostimportantandwethereforepresentacomparisonofHSPA,HSPA+andLTE

datarates.

HSPAandHSPA+arewellestablishedtechnologies,withhundredsofnetworksdeployedglobally.LTE

rolloutsbeganlate2010andinbuildingLTEisstillintheearlystages.LTEAdvancedisstillindevelopment.

(Performancefiguresquotedinthissectionare,inthelargepart,peakdatarates,fromwhichwecan

calculatethroughputratesfromonsiteexperience.Throughputfiguresarequotedwhereavailable.)

HSPAhasbeenlaunchedbyover99%ofWCDMAoperatorsglobally:

35%ofHSPAnetworks supportupto3.6MbpspeakDL 30%ofHSPAnetworks supportupto7.2MbpspeakDL 8%ofHSPAnetworks supportupto14.4MbpspeakDLHSPA+hasbeendeployedinstages,asthetechnologyhasevolved.

TheevolutionofHSPA+technologiescanbeseenfromthedatabelow.

HSPA+using64QAM, supportsupto21MbpspeakDL HSPA+using16QAMwith2x2MIMO supportsupto28Mbpspeak DL HSPA+using64QAMand2x5Mhzcarrier supportsupto42MbpspeakDL HSPA+using16QAM supportsupto11.5MbpspeakUL HSPA+usingmulticarrierontheuplink supportsupto23MbpspeakULFurtherdevelopmentofHSPAtechnologieswithinRelease9and10aimsatthefollowingdownlinkrates:

Rel9HSPA+combinesmulticarrierandMIMOin10MHzbandwidthfor84Mbpspeakdownlink HSPA+beyondRelease9shouldleadtopeakdownlinkdataspeedsexceeding100Mbps

LTEtechnologywasfirstrolledoutin2010.Inbuildingthroughputfiguresarescarceatthistime.

Thenumberofcommercialnetworkslaunchedtodateisstillquitelowandactualthroughputfiguresare

hardtocomeby.ThepeakdataratesforLTEareasfollows:

Peakdownlinkspeeds(64QAM) supportsupto100Mbps(SISO)supportsupto172Mbps(2x2MIMO)

supportsupto326Mbps(4x4MIMO)

Peakuplinkspeeds supportsupto50Mbps(QPSK)supportsupto57Mbps(16QAM)

supportsupto86Mbps(64QAM)


8/17



Table2:ComparisonofPeakDataRates:ThroughputFiguresShownWhereAvailable.

DatacourtesyHSPAtoLTEAdvancedRysavyResearchwww.3gamericas.org

MIMOtechnologyisdiscussedindetailinthenextsection.


9/17



MIMOTechnologies

ThispaperisaddressesthechallengesofrollingoutinbuildingLTEnetworks.MIMOtechnologyisa

fundamentalpartofLTE,impactingtheamountofworkandthecostsinvolvedinarolloutmorethanany

othersingleitem.WehavethereforeprovidedadescriptionofMIMOconcepts,terminologyandmodesof

operationas

they

relate

to

LTE.

MIMOisconsideredessentialforLTE,tomaximizesystemcapacityandprovidehighdatarates.Both2x2

and4x4designsarebeingconsideredalthoughonly2x2configurationsarebeingdeployedatthistime.[5]

LTEsystemsspecifythreetypesofantennatechniques;Diversity,BeamformingandMIMO

Fig3:TypicalConfigurationsforMultipleAntennaSystems

AntennadiversitycanincludetransmitdiversityorMultipleInSingleOut(MISO)andreceivediversityor

SingleInMultipleOut(SIMO)configurations:

MISO(transmitdiversity),usestwoormoretransmitantennasandasinglereceiveantenna.Thesamedataissentfrombothtransmittingantennassimultaneously,butcodedinsuchawaythatthereceiver

canidentifythedatafromeachtransmittingantenna.Thistechniquecanmakethesignalmore

resistanttofadingandisusedtoimproveperformanceinpoorcoverageareas.

Transmit Receive

SISO

MISO Transmitdiversity

SIMO Receive

diversity

MIMO


10/17



SIMO(receivediversity)usesonetransmitantennaandtwoormorereceiveantennas.Onlyonedatastreamistransmittedacrossthepathandspatialdiversityatthereceiveendcanbeusedtoimprove

SNRunderpoorchannelconditions.

TransmitBeamformingisatechniquewherebymultipledatastreamsaretransmittedovermultiple

transmitantennas,andwiththehelpoffeedbackfromthereceiver(ChannelQualityInformationCQI),the

relativephaseofthetransmittedsignalscanbeadjustedsuchthattheywillcombineconstructivelyatthe

receivertofocustheRFbeamonthatdevice.TransmitBeamformingcanbeusedtoimprovesignal

receptionandincreasetherangetoaparticularreceivingdevice.

MIMO(MultipleInMultipleOut)makesuseoftwoormoretransmitantennasandtwoormorereceive

antennas.DependingonthewayMIMOisimplemented,multipleantennaconfigurationscanbeusedto

generatehigherthroughput(spatialmultiplexing)ortoprovideamorereliablelink(diversitytechniques).

Spatialmultiplexingisusedtoincreaselinkcapacity.Theinformationtobetransmittedisdividedintoindependent

data

streams

and

each

stream

is

sent

simultaneously

from

aseparate

antenna

(multiple

spatialstreams).IfwehaveNtransmitantennasthenwemustalsohaveNreceiveantennas.Ifthe

resultantdatastreamsaresufficientlyuncorrelatedtobedistinguishablefromoneanother,thenthe

totalthroughputofthelinkwillbeNtimesthesingledatastream.

Spatialdiversitycanbeusedtoincreasetherangeand/orreliabilityofalink.Thesamedataistransmittedsimultaneouslyovermultipleindependentfadingsignalpathsandbymakinguseofthelow

probabilityofthesesignalpathsexperiencingdeepfadesatthesametime,theincomingsignalscanbe

combinedtoincreaseSNR,henceimprovinglinkreliabilityandrange.Foreffectivediversity,the

antennasattheboththetransmitterandthereceivermustbeplacedwavelengthapart.

SingleUserMIMO(SUMIMO)iscommonlyusedinLTEsystemstoincreasethedataratetooneuserin

goodradioconditions.ThemostcommondownlinkconfigurationforLTEis2x2SUMIMOusingspatial

multiplexing.(seeFig4).

MultiUserMIMO(MUMIMO).Considertwodatastreams,eachstreamoriginatingfromadifferentuser

device(seeFig4).MUMIMOreliesonthefactthatthespatialseparationbetweentheuserdevicesis

sufficientthattheinformationarrivingatthereceiveantennaswillhaveuncorrelatedpaths.Thismaximises

thepotentialcapacitygainatthereceiver(theeNodeviaDASantenna).

Oneof

the

design

motivations

of

the

LTE

standard

is

to

keep

the

terminal

or

mobile

device

cost

low.

Thereforeinordertominimiseactualtransmitantennasonthemobiledevice,multipleuserMIMO(MU

MIMO)isbeingconsideredasanattractiveoption.


11/17



Fig4:SUMIMOandMUMIMOconfiguration

Tosummarisetheabove,MIMOisamethodofusingmorethanoneantennaatthetransmitterand

receiverto

improve

communications

performance.

MIMO

has

the

potential

either

to

increase

the

capacity

ofnetworksortoenlargetheareaofagivencellwithouttheneedforadditionalspectrum.

DASAntennas

SingleUserMIMO

(LTEconfiguration 2x2SUMIMOusingSpatialMultiplexing)

MultiUserMIMO


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CorrelationinMIMOChannels

ForMIMOtobeeffectiveinachievingitsobjectivesofincreasedrangeandcapacity,theenvironmentin

whichitisdeployedmustprovidesufficientmultipath(reflectedwaves).Thisisreferredtoasnonlineof

sight(NLOS)transmissionwhichtypicallyoccursinanindoorenvironment.

In

this

so

called

rich

scattering

environment,

the

transmitted

signals

bounce

off

objects

such

as

walls,

such

thattheyarereceivedwithdistinctlydifferentprofilesatthereceiveantennas;i.e.thesignalsareeasily

distinguishablefromoneanother.Inmathematicalterms,thesignalsaredecorrelatedatthereceiver.

Conversely,inanenvironmentwithpurelylineofsightLOScharacteristics.thereisonepredominantsignal

arrivingatthereceiver.TheadvantagesofMIMOcannotbeaseasilyrealisedasthesignalsarenolonger

decorrelated.Furtherdescriptionisbeyondthescopeofthisdocument;howevermoredetailisavailable

onrequestfromCAM.

MIMOisacrucialtechnologyforimprovinginbuildingcellularcoverage.Inarichscatteringenvironment

withahighsignaltonoiseratio,aMIMOsystemcandeliverbetween70%to100%throughputandcapacity

gainsover

asingle

input

single

output

(SISO)

deployment.

The

rich

scattering

environment

describes

most

inbuildingenvironmentsandinbuildingdistributedantennasystems(DASs)canprovidehighsignal

quality.(ADCJune2010)

AchallengeforradioplannersisleveragingthemaximumperformancefromMIMOsystems,thiswill

requireinbuildingsystemsdesignedtoprovideasufficientlymultipathrichenvironmentwhilestill

achievingahighsignaltonoiseratio.


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ChallengesforInbuildingSolutions

Thusfarinthisdocumentwehavehighlightedthesoaringincreasesindataconsumptionmainlydueto

smartphonesusingdatahungrymultimediaapplications.Predictionsfordataconsumptiongoingforward

show

more

than

a

doubling

of

traffic

year

on

year

from

2011

to

2015.

Thisraisesthequestion:howlongcantheexisting2G/3GinbuildingDASscopewiththedatademands

uponthemandwhatwouldbeanappropriateupgradepathtothenextgenerationofnetworks?

HowlongcananexistingDASsupporttheincreasingtraffic?

InordertoestimatehowlonganexistingDAScansupporttheincreasingtrafficlevelswemustmakea

coupleofassumptions:

Forsitesthatcansplitintosmallercellsthecapacityofthesitemaybedoubledforadoublingofcells. NetworksupportforhigherHSPA+withoutMIMOwillalsoliftcapacitybyafactoroftwoAseachofthesechangesdoublescapacityofthesitewecanseethattheexistingDASwillbeableto

supporttrafficgrowthforanothercoupleofyearswithinanyparticularbuildingbeforeMIMObecomes

necessary.

AddedtothisisthefactthatneitherMIMOnorSmallCelltopologieswillbeaddedasanetworkwide

upgrade,butwillbedeployedinlocalisedareasonly.Thenetworkupgradescanbeperformedgradually

overtime,spreadingboththecostsandtherisksaswelearnfromeachstageofanupgrade.

WhatOptionsareAvailableforUpgradinganExistingInbuildingDAS?

Reducingcellsizebysectorisationorusingsmallcells. Largebuildingscanbedividedintosmallercells(orsectors),reducingthenumberofuserspercell(orsector),therebyincreasingcapacity.The

disadvantagesarethattherearephysicallimitationstohowsmallcellscanbemade;smallercellsmay

meanmorecellswhichinturnrequiremoreNodeBs,whichrequiremorespaceandmorepower.Re

cablingofthesystemeachtimeasmallcellisaddedcanbeexpensive.

IncreasingdatarateswithMIMO.Thishastheadvantagethatcapacitycanbeincreasedwithoutusingmorespectrum.Thisoptioncouldproveexpensiveifcablinghadtobedoubledup;however,thereare

optionsavailableforrunningmultipleantennasoveronecable,oroveranEthernetlink.

DeployingLTEtospecificareaswithinthebuilding.ThisisundoubtedlythewayLTEwillbedeployedforthereasonsgivenearlieri.e.capacityisonlydeliveredwhereitisneeded.AnyupgradetoLTE

technologywillfollowthisupgradepathforreasonsofcostandefficiency.TheadvantagesofMIMO

arethatcapacitycanbeincreasedwithoutusingadditionalspectrum.Themaindisadvantageas

mentionedaboveisdoublinguponcablingtothemultipleantennas.


14/17



WhatOptionsareAvailableforDeployingaNewInbuildingDAS?

ItisafactthatGSM/UMTSwillcomprisetheoverwhelmingmajorityofsubscribersoverthenextfivetoten

years,evenasnewwirelesstechnologiesareadopted.Therefore,eveninthelightoflargeincreasesindata

demand,anewDASdeploymentwouldmostlikelystillbebasedonabuildingwide2G/3Gnetworkwith

smallerareasofhighcapacityLTEnetworks,onlywherethedatademandisrequired.TheLTEsectionsof

thenetwork

would

be

similar

to

the

upgrade

options

given

in

the

previous

section.

EstimatedcostsfromCAM,foranewDASinstallationcomprisingmaterialsdescribedbelow,areasfollows:

20antennas 700mcoaxialcable 10splitters 10couplersCosts:

1.

2G

/

3G

/

4G

SISO

System:

22,000

to

design

and

install

2. 2G/3G/4G2x2MIMOSystem: 32,000todesignandinstall

3. 2G/3G/4G4x4MIMOSystem: 46,000todesignandinstall

Figuresarebasedonthefactthatthematerialsaredoubledineachcasebutthelabourrequiredforeach

installationdoesnotdouble.Asapercentage,a2x2systemwouldbe45%moreexpensivetoinstallanda

4x4system109%moreexpensive.

ThesecostshoweverwouldonlybeapplicableifweweretodeployMIMOoveranequivalentareatothe

SISOinstallation.Aswehaveseeninthisdocument,thisrolloutscenariomaynotbethemostsuitable,or

themost

cost

effective.

Todeliverpoolsofhighcapacity,usingMIMO,onlywhereitisneededwouldprobablycostmorefromthe

pointofviewofplanningandsitesurveysbutwillultimatelybecheaperthandeployingMIMOthroughout

thebuilding.Thisissueisopentodiscussion.


15/17



ANovelApproachtoDeployingInbuildingLTECoverage:(CellularoverLAN)

InprevioussectionswehavediscussedtheadvantagesanddisadvantagesofdeployingMIMOtechnologies

forinbuildingnetworks.Oneofthemaindisadvantagesisthecostofrunningmultiplecablestothe

multipleantennasinaMIMOsystem.Thereareafewoptionswherebymultipleantennascanbefedfrom

asinglefeeder.OneoptioninvolvesfeedingtheantennasviatheexistingCAT5/6cablingwithinthe

building.

Thissolution,calledMobileAccessVEisdesignedtodeliverinbuildingLTEcellularservicesoveranexisting

CAT5/6LANinfrastructure,whilemaintainingfullEthernetandwirelessLANcapabilities.Thevendor

claimsthefollowingperformancefiguresandfacilities:

Extendscarriergrade,5barcoveragefor2G,3G,4GserviceswithMIMO Reducesinstallationtimebyhalf,ascomparedwithconventionalsolutions transparentlycoexistsalongsidetheLANwithoutimpactingLANperformance SupportsconnectivitytoanytypeofoperatorRFcapacitysource Offersproactiveendtoendnetworkmonitoring

Plug

and

play

design

scales

cost

effectively,

allowing

customers

to

choose

where

new

services

are

activated

ResultsfromanactualMobileAccessVEinstallationgivethroughputfiguresforanindoorLTEdeployment:

70dBmcoveragewastestedin90%ofthebuilding,followingMobileAccessVEdeployment EachVEPodcovered10,000squarefeet. Spatialmultiplexed2x2MIMOand64QAMwasverifiedusingtheLTELGUSBdongle ThemeasureddatathroughputatMIMOconfigurationwas:

15MbpsforUL(uplink)dataspeed

40

Mbps

for

DL

(downlink)

data

speed

SISOperformanceequivalentsofferlessthan35%ofMIMOthroughput(15MbpsUL,25MbpsDL)(http://www.mobileaccess.com)

Thissolutionprovidesanadvantageinitsquickandeasyinstallation timesandMIMOsupportat4G,

withoutimpactingontheexistingLANperformance.MobileAccessVEisalsothefirstcellularsolution

validatedwiththeCiscoUnifiedWirelessNetwork.MoredetailisavailableonrequestfromCAM.


16/17



LTEFemtocells

AFemtocellisasmallbasestation,designedtobedeployedwithinhomeorsmallbusinesspremisesto

provideenhancedcoverage.Thecoverageandcapacitymadeavailablebyusingthesmallcellapproach

withinbuildingsiswellsuitedtoLTEdeployment.

LTEFemtocells

are

supported

within

3GPP

as

early

as

Release

8(2008)

and

are

identified

as

Home

eNode

Bs(HeNB).However,unlikethe3GFemtocell,thereiscurrentlynodefinedarchitecturalstandardinplace.

ThelevelofinterestfromoperatorsisdrivingtheFemtocellecosystemforwardatapace.Enterprise

Femtocellsthatcouldprovidecoverageinlargebuildingsarenowinthepipeline,supportingfemtofemto

handovers.

CellularAssetManagementwillbehappytodiscussthepotentialofFemtocellsuponrequest.

Conclusions

Thepurposeofthisdocumenthasbeentopromotediscussiononthebestwaytoservethesoaringlevels

ofdatademandexpectedoverthenextfewyears,usinganinbuildingDASsystemandnewtechnologies

suchasLTE.Themainpointsare:

Smartphonedevicesareexpectedtomorethandoublethetrafficdemandedofinbuildingsystemsyearonyearfrom2010to2015.

ToupgradeanexistinginbuildingDASfortheincreaseindatatherearetwomainoptions:reducethesizeofeachcellandincreasethedataratessupportedbytheDAS.

TosupportthedataratesofHSPA+andLTEtheinbuildingsystemswillneedtobeupgradedforMIMOantennatechnology.

FemtocelltechnologyforLTEcouldprovidesmallcellcapacitysolutions,althoughitisstillindevelopment.

AlternativedistributionsystemssuchasMobileAccessVEcouldprovideaquickandsimplerupgradepathwithextracapacitybeingaddedtoareasasthetrafficincreases.

Doweupgradenow?Inthenexttwoyears?Morelikelywewillseenetworksupgradegradually,providing

extracapacityonlyinlocalisedareaswhereitisrequiredandleavingthe2G/3GDASinstallationstohandle

thewiderareacoverage.


17/17



References

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http://eandt.theiet.org/magazine/pastissues/index.cfm

4. Ofcom TheCommunicationsMarket2010(August)http://stakeholders.ofcom.org.uk/binaries/research/cmr/753567/CMR_2010_FINAL.pdf

5. AgilentTechnologies.http://www.home.agilent.com/agilent/application.jspx?nid=34563.0.00&lc=eng&cc=GBLTEimplementationofMIMO

6. HSPAtoLTEAdvanced,RysavyResearchSept2009http://www.4gamericas.org/

7. NECShowsHowSmallCellLTEDeploymentisSmarterWaytoSustainableFuture:MobileBroadbandMobileWorldCongress

Feb

2011

http://www.nec.com/

Documents

CAM Technical Paper LTE.pdf