WCDMA Frequency Refarming:A Leap Forward Towards

Ubiquitous Mobile BroadbandCoverage

Maximizing returns on legacyassets and resourcesMany markets are ready for refarmingtoday; others are poised to followsuit. Recognizing the potential ofrefarming early on, Nokia SiemensNetworks has developed a cost- andenergy-efficient solution that enablesoperators to adapt and adopt at theirown pace. Leveraging uniquehardware and software features, thissolution helps operators migrate theirnetworks to WCDMA, smoothly andseamlessly. To this end, it reuseslegacy assets and resources betterthan any other vendor’s offering.All this, as well as Nokia SiemensNetworks’ end-to-end offering of radioaccess equipment, functionalities,management systems, andprofessional services, make thetransition simple and the overallsolution far less complex.

Mobile operators seeking to deliver3G services to sparsely populatedrural areas have faced a prohibitivecost problem. To date, 3G coverageover large areas has been anexpensive proposition, stallingefforts to bring broadband mobiledata services to far-flung customers.Now there is a viable solution to thiscost problem: Using 3G over the900 MHz spectrum band – that is,WCDMA frequency refarming– can afford people access to moresophisticated mobile services. Whatis more, WCDMA refarming to900 MHz affords operators excellentopportunities to grow their businesswhile making the most of legacyassets, as this paper will show.

Better performance indoors and outOperators wishing to introduceWCDMA to their GSM, CDMA, orTDMA bands can now refarm partor all of their frequencies and rollout 3G at remarkably low cost. Lowerfrequencies transmit over greaterdistances and penetrate betterindoors. This means fewer sites covergreater areas, saving considerablerollout and operating costs to bringbona fide broadband to rural areasand improved data rates tometropolitan indoor locations.

Contents

02 Executive summary

03 Why WCDMA in the 900 MHz band?

05 Market and regulatory conditions

07 Mastering the technical challengesof WCDMA frequency refarming

09 Nokia Siemens Networks’Frequency Refarming Solution

11 Abbreviations

For reasons of simplicity and clarity, this paper discusses900 MHz refarming. All the statements apply equally to850 MHz refarming.

02/12 WCDMA Frequency Refarming: A Leap Forward Towards Ubiquitous Mobile Broadband Coverage

ExecutiveSummary

Scenario 1: Rural 3Gcoverage extension

Scenario 2: Urban 3Gcoverage improvement

Scenario 3: Initial 3G rollout

WCDMA 900WCDMA 2100

The physical advantageThe physics of radio wavepropagation help explain one of thegreat advantages of WCDMA 900:The lower the carrier frequency, thefurther radio signals can travel. Thismeans it takes fewer radio cells tocover the same area, makingWCDMA 900 the perfect solution forextending coverage (see Figure 1).What is more, a radio signal travelingthrough the walls of a building ata lower carrier frequency is lesssusceptible to penetration loss. Withthe benefit of this property, WCDMA900 can extend indoor coverage andimprove service in metro areas.Perhaps most important to operators,it can do all this at remarkably lowcost and with compelling efficiency.Measurements of and experience withthe first commercial WCDMA 900network confirm that its performanceis comparable to that of WCDMA 850networks. Because radio propagationproperties at 900 MHz and 850 MHzare all but identical in the real world,WCDMA 900 is sure to follow inWCDMA 850’s successful footsteps.

Operators have many compellingreasons to deploy WCDMA in the900 MHz band. The greatest obstacleto WCDMA 900’s deployment to datein most countries has been regulators’practice of assigning 900 MHz bandsto GSM. Tasked to handle heavyGSM traffic loads, the band frequentlyhas little or no remaining capacityavailable for 3G traffic. But now, withan eye to the potential of ubiquitousmobile broadband, regulators arebeginning to see the promise andbenefits of WCDMA in 900 MHzbands. Countries such as France,Finland, Australia, and New Zealandhave already given it the green light.

Why WCDMAin the 900 MHz band?

WCDMA 900 vs. GSM 900A brief review of WCDMA’sdeployment in many markets suchas Western Europe helps explainthe potential impact of WCDMA 900on coverage and services. Authoritiesopted to introduce WCDMA in theUMTS core band at 2100 MHz, afrequency reserved for IMT-2000technologies. This put WCDMA at adisadvantage in these markets, andGSM long remained the dominanttechnology for the 900 MHz band.But recent upgrades to HSPA havetransformed WCDMA networks intoreal mobile broadband accessplatforms. Of course, HSPA dataservices demand a carrier frequencythat propagates further. And userstypically wish to enjoy data servicesin buildings, and this requires a carrierfrequency with better penetration.To date these two constraints havelimited HSPA mobile broadbandservices coverage to lag significantlybehind voice service coverage.

Figure 1: Coverage-driven application scenarios for WCDMA 900

04/14 WCDMA Frequency Refarming: A Leap Forward Towards Ubiquitous Mobile Broadband Coverage

Figure 2 compares the coverage ofGSM/EDGE and WCDMA/HSPA atdifferent frequencies. Note that itindicates cell area in a typicalsuburban environment in whichservice (voice and 1 Mbps data)is available within a building.

WCDMA 900 vs. WCDMA 2100Bringing a real mobile broadbanduser experience to less denselypopulated areas has to date beendeemed economically infeasible. Nowoperators can deliver high-revenuesservices profitably by running HSPAin the 900 MHz band. Savings comebuilt-in: WCDMA 900 requires 65%fewer sites than WCDMA in the2100 MHz band. The total cost ofownership for WCDMA in a ruralenvironment is lower – as much as60% lower factored over five years.Better radio propagation properties at900 MHz translate to better services,delivered faster to more users.Even in buildings, users in a typicalsuburban environment can enjoy 1Mbps data rates when HSPA 900 isdeployed at GSM 900 base stationsites.

Fast factsThe answer to the question of whyWCDMA in the 900 MHz band is, ina nutshell, because it offers

• The coverage-driven rolloutadvantage of cells that are2.8 times larger

• TCO reduced to 40% comparedwith 2100 MHz networks

• Cost-efficient 3G coverage oflarge areas, with 65% fewer sitescompared with WCDMA in the2100 MHz band

• Improved data rates and coverageindoors

WCDMA 2100 1Mbps

WCDMA 2100 Voice

GSM 1800 Voice

GSM 900 Voice

WCDMA 900 1Mbps

WCDMA 900 Voice

0.0 2.0 4.0 6.0 8.0 10.0 12.0

Cell area [km2]14.0

1 Mbps data serviceon GSM voice grid

HSPA data rates

Outdoor

kbps

Indoor, -10 dBpenetration loss

Indoor, -20 dBpenetration loss

6000

5000

4000

3000

2000

1000

0

+60%

+130%

HSPA 900HSPA 2100

Figure 2: A comparison of GSM and WCDMA coverage at different frequencies. It depicts cell area in a typical suburban environment with service (voice and 1 Mbpsdata) available within a building. WCDMA 900 provides 1 Mbps coverage using the GSM site grid.

Figure 3: Indoor penetration of HSPA at 2100 MHz and 900 MHz. The higher the penetration loss causedby the building’s walls, the greater HSPA 900’s improvement in performance compared with HSPA 2100.

Opportunity knocks for operators…Mobile broadband is taking off. Asoperators and device manufacturers’recent marketing campaigns wouldattest, the notion of mobile accessto the full Internet has real mass-market appeal. With demand formobile broadband services risingfast, extending broadband coverageis becoming a compelling businessproposition for mobile operators.Most have already responded byupgrading WCDMA networks viaHSPA to create real mobile broadbandaccess platforms.

… and vendors alikeCompelled to respond to fast-growingdemand, device vendors are doingtheir part to commercialize mobilebroadband: HSPA-enabled userdevices are on the verge of hittingthe consumer mass-market pricepoint. Vendors had rolled out morethan 120 WCDMA 850 user devicesby November 2007, and the firstWCDMA devices supporting 900MHz are now available, among themNokia’s debut WCDMA 900-enableddevice launched in June 2007. 2008will see many multi-band WCDMAdevices make their way into themarket. Industry players expect allvendors to offer data cards and USBmodems very soon, and WCDMA900 to feature in a significant numberof 3G terminals sold in Europe.WCDMA 900 is likely to becomea standard feature by 2009.

Responding to the call for actionRegulators wish to extend ruralcoverage, speed the uptake of mobilebroadband, and improve indoorcoverage. Many have seen just howinstrumental refarming can be in thepush for mobile broadband, and areacting to make it work. In Europe, forexample, the European Commissionis considering a stronger pushtowards refarming in the 900 MHzband with a proposed law allowingnew technologies to coexist with GSMin the 900 MHz and 1800 MHz bands.The goal is to guarantee continuedGSM services in the EU, whileopening the door to WCDMA/HSPA.

Market andregulatory conditions

The evolutionary pathof WCDMA 900Like WCDMA 2100, WCDMA 900 isevolving towards higher data speedsand increased efficiency. 3GPPRelease 8 will bring downlink datarates up to 43 Mbps and uplink datarates up to 11 Mbps. Otherevolutionary advances in HSPAwill reduce mobile devices’ powerconsumption and therefore increasetheir operational autonomy.

Compared with GSM 900, the singlebiggest advantage of WCDMA 900is its superior mobile broadbandcapability. Bearing this in mind, theI-HSPA’s flat architecture is another

means of optimizing the WCDMA900 network. I-HSPA 900 increasescost efficiency by decoupling trafficgrowth and network capacity costsand simplifying the user plane bystreamlining it in flat, two-node-architecture. This brings to usersthe benefit of lower latency, whichtranslates to faster response for manydata applications.

I-HSPA’s flat architecture and air-interface improvements brought aboutby HSPA’s evolutionary advance canbe leveraged to optimize WCDMA900 networks’ mobile broadbandperformance and efficiency.

GGSN

Node-B

UE

3GPP open interface

3GPP open interface

SGSN

Figure 4: I-HSPA 900. I-HSPA’s flat networkarchitecture is also applicable to WCDMA 900.

WCDMA refarming initiativesaround the worldMany national regulators recognizedthe potential of WCDMA/HSPA at900 MHz, and are working to enableWCDMA’s introduction in the 900 MHzband. By December 2007, Finland,France, and Switzerland, a non-EUcountry, had adopted the EuropeanCommission’s policy. Another casein point is CEPT, which sanctionedWCDMA on 900 MHz and 1800 MHzbands in December 2006. In theAsian Pacific region, Australia, NewZealand, and Indonesia have givenpermission to proceed with WCDMA900. Aiming to promote more flexibleuse of the spectrum, Britain’scommunications and media regulatorOfcom has proposed freeing up the

06/12 WCDMA Frequency Refarming: A Leap Forward Towards Ubiquitous Mobile Broadband Coverage

900 MHz band and awardingspectrum in this band in 2009 withouttechnology-specific restrictions.Decisions on WCDMA refarming arepending in several other EU countries,Spain and Portugal among them.Israel as well as some Asian Pacificand Latin American countries areaiming to refarm WCDMA to the850 MHz band.

Proven in commercial deploymentsCountries in many other parts of theworld awarded spectrum withouttechnology-specific restrictions.WCDMA 850 networks are up andrunning successfully in the Americas

* Near-term WCDMA refarming potential

North America• 700, 850* and 1900 MHz• 1.7/2.1 GHz

Latin America• 2100 MHz• 850*, 900*, 1800 and 1900 MHz• 1.7/2.1 GHz

EMEA• 2100 MHz• 850*, 900* and 1800 MHz• 2.6 GHz

APAC• 2100 MHz• 850*, 900*, 1800 and 1900 MHz

Operating 3GPP Band Total Uplink Downlinkband Release name spectrum [MHz] [MHz]

Band I Rel. 99 2100 MHz 2x60 MHz 1920-1980 2110-2170

Band II Rel. 5 1900 MHz 2x60 MHz 1850-1910 1930-1990

Band III Rel. 5 1800 MHz 2x75 MHz 1710-1785 1805-1880

Band V Rel. 6 850 MHz 2x25 MHz 824-849 869-894

Band VIII Rel. 7 900 MHz 2x35 MHz 880-915 925-960

Main 3GPP bands for refarming

Figure 5: The main WCDMA frequency bands and near-term refarming potential.

and Australia, providing proof of thetechnology’s outstanding performanceat lower frequencies. WCDMA hasthus proven its merits and commercialviability at lower frequencies.

Now a WCDMA 900 network hasdebuted. In November 2007, theFinnish network operator Elisalaunched commercial operationswith the world’s first WCDMA 900network. In view of fast rising demandfor ubiquitous mobile broadband,regulatory bodies’ endorsement, andthe availability of devices supportingWCDMA 900, many more are sureto follow.

Operators seeking to capitalize on thepotential of WCDMA 900 refarmingmust first protect legacy businessinterests, sustain current operations,and find a way to contain rollout costs.In other words, operators aiming torefarm frequencies must resolvethree major issues; that is, how to

• Minimize the impact of WCDMAfrequency allocation on their GSMbusiness

• Sustain business with users whohave GSM-only phones

• Cut operational expendituresassociated with the added WCDMA900 radio access layer

Making the most of narrowlydefined spectrumThe 900 MHz band, denoted asBand Class VIII, is defined as thepaired bands from 880 to 915 MHzin the uplink direction, and from 925to 960 MHz in the downlink. Thismeans overall band potential comesto down to just two times 35 MHz,compared with two times 60 MHzin the UMTS core band (band I) at2100 MHz. Operators are compelledto share this spectrum; what is more,it must also support continued GSM/EDGE operation.

Mastering the technicalchallenges of

WCDMA frequency refarming

“Improved customer experience is our objective whenwe are now widening the coverage of our 3G services.Elisa has been the leader in driving the mobile broadbandmarket in Finland. This launch further underlines ourcommitment to continuous development of our serviceoffering. Thanks to the Nokia Siemens Networks frequencyrefarming solution, we are now running WCDMA andGSM efficiently in our 900 MHz frequency allocation,enabling us to extend our 3G services cost-effectivelyfrom cities to the less populated areas of Finland.”

Veli-Matti Mattila, President and CEO, Elisa Corporation

08/12 WCDMA Frequency Refarming: A Leap Forward Towards Ubiquitous Mobile Broadband Coverage

The answer is, of course, to sparebandwidth by condensing carrierspacing. Nokia Siemens Networks’advanced WCDMA filter solution andcoordinated GSM-WCDMA networkplanning, together with intelligentlyallocated power-controlled trafficchannels (non-BCCH) in GSM sitesreused for WCDMA, can reducecarrier bandwidth from 5.4 MHz to4.2 MHz. This leaves 1.2 MHz moreof the valuable spectrum to bedevoted to GSM use. Standardterminals support this reductionbecause nearly all signal energyin a modulated WCDMA carrier iswithin this 4.2 MHz range.

Coverage-based handovers enablecontinuous service provisioning,ensuring potential discontinuitiesin cell coverage go unnoticed bysubscribers. With Nokia SiemensNetworks’ service- and load-basedintersystem handovers, the operatorcan strike an optimum balance ofthe system load between GSM andWCDMA networks.

2. Sustain business with userswho have GSM-only phonesUsing GSM spectrum more efficientlyis another way of mitigating theimpact of WCDMA 900 refarmingon ongoing GSM operations andmaking the most of the remainingGSM carriers’ capacity.

Frequency hopping techniques,dynamic power control, anddiscontinuous transmission are justthree of the many means of boostingGSM spectral efficiency.

A clear action plan…Operators looking to extend their 3Gnetwork’s reach by means of WCDMA900 need a clear action plan thathelps them rise to the three keychallenges of refarming. As thesupplier of the world’s first commercialWCDMA 900 network, Nokia SiemensNetworks has a proven end-to-endsolution engineered specifically totackle these challenges. This solutioncombines unique radio accessequipment and features with anintegrating OSS and professionalservices to introduce WCDMA 900smoothly.

…to tackle three big challengesA closer look at these threechallenges, and Nokia SiemensNetworks’ approach to each, follows.

1. Minimizing the impact ofWCDMA frequency allocationon GSM businessThe 3rd Generation PartnershipProject calls for a carrier spacing of5.4 MHz between WCDMA and GSMcarriers. 3GPP’s assumption baseson the performance of typical RFfilters in base stations and on a worst-case power level scenario in adjacentcarriers. 3GPP’s recommended carrierspacing poses a challenge for a2G/3G operator wishing to introduceWCDMA 900. If the operator has atotal of 10 MHz paired spectrum inthe 900 MHz band available, thiscarrier spacing leaves just 4.6 MHzbandwidth to sustain ongoing GSMoperations.

Other advanced functionalities suchas Adaptive Multi Rate (AMR) speechcoding and Dynamic Frequency andChannel Allocation (DFCA) serve tofurther boost GSM spectral efficiencyby ensuring tighter reuse factors innetwork planning. In practice, AMRmay be used to double GSM capacity,and DFCA can serve to double AMR-enabled capacity gain. For example,if AMR alone can boost TRX capacityby two from two to four, thecombination of AMR and DFCAextends TRX capacity to six.

3. Cut operational expendituresassociated with the addedWCDMA 900 radio access layerIntroducing another radio accesslayer adds to the operational effort.The extra effort may be minimized bymaking intelligent use of synergiesat all levels. Site overhead, mainlydriven by site rental, energy, andtransmission costs, is another majorexpense. Compact, energy-savingWCDMA 900 base stations that areable to utilize legacy site hardwaresuch as antennas and accessoriescan augment existing GSM siteswithout significantly adding to thesecosts. And a common backhaularchitecture and infrastructure forGSM and WCDMA can reducetransmission costs.

Planning a network and settingparameters are big cost factors at thestart of a project. Later, assuranceand optimization processes becomepart of the operating equation, anddrive network management costsaccordingly. An integrated planningand operations solution, automatedand proven many times over, speedsup the initial phase, prevents errors,and slashes start-up costs. A commonOSS solution for GSM and WCDMAin all bands reduces operational costsbecause shared procedures translateto less training effort, better resourceutilization, fewer errors, and greaterefficiency.

For easier reading, the following section does not specifically mentionthe 850 MHz band (UMTS band V, offering two times 25 MHzspectrum), but all statements apply equally to 850 MHz refarming.

Nokia Siemens Networks seesWCDMA 900 as the perfect platformfor bringing the mobile broadbandexperience to users in rural areas.The lower frequency offers the fringebenefit of closing suburban and urbanmobile broadband coverage gaps,especially within buildings. This is aside-effect operators and metro usersalike will value.

Because the company believes sostrongly in the merits of frequencyrefarming, it has developed networkplanning services and powerful toolsfor analyzing traffic and the legacynetwork’s design. Armed with thisinsight, Nokia Siemens Networksengineers tailor the best refarmingsolution for the given scenario,selecting WCDMA spectrum allocationand spectral efficiency featuresspecifically to satisfy the operator’sneeds. This solution approachreduces WCDMA bandwidth from5.4 MHz to 4.2 MHz and serves toincrease GSM spectral efficiency.

Every WCDMA network delivered byNokia Siemens Networks, includingWCDMA 900 MHz, is HSDPA- andHSUPA-enabled with a simplesoftware download. Nokia SiemensNetworks’ refarming solution supportsflat I-HSPA network architecture andis ready for the HSPA air interface’sfurther evolution.

Nokia Siemens Networks’ load- andservice-based handover parametersadapt efficiently to enable dynamictraffic allocation and ensure best-casetraffic balancing for the combinedGSM and WCDMA networks acrossall frequencies. In addition, NokiaSiemens Networks provides acomprehensive set of GSM spectrumefficiency features that help shift somefrequencies from GSM to WCDMA.

Compact, modular, and engineeredto consume less power, the Flexibase station enables effective siteacquisition and re-use. But small basestations are just part of the savingsequation. This approach allowsoperators to reuse GSM sites forWCDMA and HSPA to contain rentalcosts. Beyond that, these ultra efficientbase stations are much cheaper tooperate because they minimize thesite’s overall power consumption,keep heat dissipation in check, andreuse legacy site equipment, includingantennas, antenna lines, and powersystems. And with proven networkimplementation services steeringand supporting rollout, an easy andorderly transition is assured.

This refarming solution builds on one-pipe backhaul architecture, enablingoperators to scale transport capacityto suit HSPA services’ bandwidthdemand, and migrate traffic smoothlyfrom GSM to HSPA. The commonNetAct OSS for 2G and 3G automatesplanning and parameter optimization,and harmonizes operationalprocedures. The common OSSapproach for GSM and WCDMA 900and 2100 facilitates northboundintegration.

Nokia Siemens Networks’Frequency Refarming Solution

Committed to WCDMA frequencyrefarmingDeeply confident in the validity ofWCDMA frequency re-allocation,Nokia Siemens Networks has madea strong commitment to refarming.Some markets are ready today; otherswill be soon, and device vendors aregearing up to support refarming. Thusthe company’s cost- and energy-efficient refarming solution letsoperators deliver a genuine broad-band experience to rural users’handsets. Nokia Siemens Networks’solution can lower the site count bya remarkable 65%, and total cost ofownership by an equally noteworthy60% over five years. Users in suburbiacan enjoy data rates of 1 Mbps, eveninside buildings. And HSPA 900 MHzwill support the same data rates asHSPA 2100 MHz in upcoming 3GPPreleases.

Strong arguments…All these arguments and the manymore discussed throughout the paperspeak strongly in favor of WCDMAfrequency refarming. And NokiaSiemens Networks’ role in helpingthe Finnish communications servicecompany Elisa launch the world’sfirst commercial WCDMA 900 MHznetwork speaks strongly in favor ofits ability to deliver on the promiseof frequency re-allocation.

…for a strong solutionWith its WCDMA FrequencyRefarming Solution, Nokia SiemensNetworks aims to help operatorsefficiently provide 3G coverage bydeploying WCDMA into 900 MHzand sharing bandwidth with GSM.This end-to-end solution for smoothWCDMA frequency refarming ensuresGSM capacity and service qualityremain unchanged, enabling 3G andGSM to co-exist. Best of all, operatorscan make the most of legacy assetsand resources while capitalizing onpromising new broadband businessopportunities.

10/12 WCDMA Frequency Refarming: A Leap Forward Towards Ubiquitous Mobile Broadband Coverage

GSM & WCDMAfunctionalities

OSS tools & functionalities

BTS site system

Services

Figure 6: Nokia Siemens Networks’ brand of WCDMA refarming leverages comprehensive 2G/3Goptimization to ensure highly efficient WCDMA and GSM operation in the 900 MHz band.

AMR Adaptive Multi RateBCCH Broadcast Control ChannelCAPEX Capital ExpenditureCEPT Conférence Européenne des Administrations des Postes et des TélécommunicationsDFCA Channel AllocationEDGE Enhanced Data Rates for GSM EvolutionGSM Global System for Mobile CommunicationsHSDPA High-Speed Downlink Packet AccessHSPA High-Speed Packet AccessIMT International Mobile CommunicationsOPEX Operating ExpenditureOSS Operations Support SystemTDMA Time Division Multiple AccessUMTS Universal Mobile Telecommunications SystemWCDMA Wideband Code Division Multiple Access

Abbreviations

www.nokiasiemensnetworks.com

AuthorNokia Siemens Networks is a leading global enabler of communications services. The company provides a complete, well-balanced product portfolio of mobile and fixed network infrastructure solutions and addresses the growing demand forservices with 20,000 service professionals worldwide. Nokia Siemens Networks is one of the largest telecommunicationsinfrastructure companies with operations in 150 countries. The company is headquartered in Espoo, Finland.

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