Solving the Mobile Backhaul challenges

8/8/2019 Solving the Mobile Backhaul challenges

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White paper

Executive SummaryWDM has already played an important role in aggregation o celltrac, but in the past was seldom used to provide bandwidthto the cell site itsel. But now a highly competitive and compre-hensive WDM-based solution that oers scalability, exibility,

and cost optimization o backhaul requirements ranging romthe cell site through aggregation and metro transport networkis available. Transmodes Multi-Service Mobile Backhaul Solutionis compelling or mobile backhaul because it oers carriers thescalability, exibility, and operations model that mobile and fxed/mobile operators need, providing one solution that can extend allthe way down to the base station, providing native transport orTDM and Ethernet trac, broad synchronization support includingmultiple synchronization streams on one wavelength only, and aneasy migration path rom TDM to Ethernet cost eectively and atthe pace they need.

Transmodes Multi-Service Mobile Backhaul Solution is importantbecause although mobile broadband technologies associated

with 3G, 4G and WiMAX are creating important new multimediaservice opportunities or both mobile operators and fxed/mobileoperators worldwide, the revenue opportunity created by mobilemultimedia services can only be realized i the very real challengeo fnding more cost eective backhaul transport is overcome.Choosing the right solution to cost eectively scale backhaulrom the cell site back into the network can make or break thebusiness case on which carriers new mobile multimedia servicesare justifed. The use o fber or backhaul makes increasing sensenow as the backhaul network begins to scale dramatically -particularly when coupled with an innovative and cost eectiveWDM solution that provides exibility, scalability, and opera-tions synergies while oering native TDM and Ethernet transportand serving in backhaul both in an aggregation role as well as

providing access to the cell site.

The right backhaul solution must do ar more than just opti-mize cost; it must also oer the low latency required to supportstringent synchronization requirements over a packet transportnetwork, and support both TDM and Ethernet trac natively iit is to support the installed base and acilitate a smooth migra-tion. The availability and cost o licensed spectrum a backhaulsolution might require is also an issue to consider, as are the dis-tance capabilities and perormance, availability and reliability oany backhaul transport solution under evaluation. The potentialto leverage the operations synergies created by having a solutionthat meets cell site as well as metro aggregation and transportrequirements is another consideration, as is the operations

synergies possible in fxed/mobile networks serving in PBX accessand DSLAM aggregation roles.

The best backhaul solution also needs to support backhaul rommultiple generations o radio technologies well into the uture,

and may also need to support separate synchronization streamsor wholesale operators and those buying backhaul rom a whol-esaler, and or those mobile operators that choose to sharetheir backhaul network with a competitor. The latency, QoS andscalability requirements that multimedia trac now present to

mobile operators are ar more complex than what they had todeal with in the past, creating the need or a more cost eective,exible, and scalable backhaul solution.

Now mobile operators can enjoy all the advantages possible ina fber-based WDM solution or backhaul thanks to Transmode,which has created the most exible and cost eective backhaulsolution available and made fber to the cell site as well as aggre-gation nodes a compelling alternative. Transmode oers a rangeo Access Solutions and Hub Solution as part o its Multi-ServiceMobile Backhaul Solution, provides a simple and eective hybridapproach by which native E1/T1 and Ethernet trac streams canbe transported in parallel as is done in hybrid microwave, andgives mobile operators a variety o options tailored to their needs

while enabling a smooth and ecient migration to an Ethernetor all-IP over WDM based backhaul network.

This white paper discusses the problems that Transmodes Multi-Service Mobile Backhaul Solution solves in the mobile network andthe ultimate benefts this solution provides to mobile operators.

Solving the Mobile Backhaul challenges

This whitepaper was authoredby Telecom Strategy Partnerson behal o Transmode.

About TSPTelecom Strategy Partners provides market and competitiveanalysis and develops market strategy, positioning, messag-ing, customer presentations, business case analyses and whitepapers. A trusted advisor with signifcant Marketing expertisegained working as employees o both vendors and operators,we augment our clients internal Marketing and Strategy re-sources and interact as part o the team to assist in objectivelyevaluating customer requirements, the market environment,portolio competitiveness and competitive landscape. We thenhelp clients apply this insight to design, produce, and implementully optimized product and service marketing strategy andprograms that set appropriate direction, eectively dierentiate,clearly and persuasively communicate, enhance competitiveness

and maximize proftability.Visit us at http://www.telecomstrategypartners.com


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Transmode Provides an Ecient andFlexible WDM-based Backhaul Solution

WDM has already played an important role in aggregationo mobile trac, but in the past was seldom used to providebandwidth to the cell site itsel. But, given the capacity anddistance requirements, a WDM-based solution that oersscalability, exibility, and cost optimization o backhaulrequirements ranging rom the cell site through aggregation andmetro transport network has strong appeal i the cost is right.Transmode has been an innovator in engineering cost eectivecarrier class WDM systems, and its Multi-Service Mobile BackhaulSolution is compelling because it oers carriers the scalability,exibility, and operations model that mobile and fxed/mobileoperators need, providing a solution that can extends all theway down to the base station, oering native transport or TDMand Ethernet trac, supporting options in synchronization and

multiple synchronization streams on one wavelength, and givingoperators an easy migration path rom TDM to Ethernet costeectively and at the pace they need.

The Importance o Choosingthe Right Backhaul SolutionMobile broadband technologies associated with 3G, 4G andWiMAX are creating important new multimedia service oppor-tunities or both mobile operators and fxed/mobile operatorsworldwide, but the revenue opportunity created by mobile mul-timedia services can only be realized i the very real challenge ofnding more cost eective backhaul transport is overcome

Figure 1 illustrates the cost challenges associated with rolling out3G and 4G multimedia services.

Figure 1. Cost Challenges o 3G and 4G Multimedia Services MandateBackhaul Optimization

The Mobile Broadband MultimediaServices OpportunityMobile broadband capacity requirements are being driven by 3Gand 4G technologies like HSPA, EV-DO Rev A and B, and HSPA+.WiMAX and LTE are poised to enable even greater advances inmobile data rates or the subscriber, creating important newmultimedia service opportunities or mobile operators and fxed/mobile operators worldwide.

Just how big the revenue opportunity associated with mobilebroadband will be is evident rom the sheer growth in mobilebroadband subscribers worldwide, which has already surpassedthe total number o fxed broadband users and is expected tosurpass the 1 billion mark in only a ew years. While the increase

in mobile broadband subscribers in itsel has put signifcant pres-sure on the existing backhaul network resources, the real strainon the backhaul network is only just beginning.

Mobile operators are experiencing sustained growth rates inmobile data trac typically ranging between 150% to 300% an-nually or higher, even ater the initial spike o the ramp up as 3Gservices are introduced, which can cause very painul short termincreases that are much higher. And this is only the start, as theinux o smart phones and computing devices supporting highermodulation ormats and data rates is expected to drive thatgrowth higher, and LTE will drive it even urther.

Sources o Strain on the ExistingBackhaul NetworkAs i the strain on backhaul network resources imposed by

greater availability o 3Gand 4G mobile broadband capabledevices is not enough, it is accompanied by additional strain dueto the growing availability o bandwidth intensive multimediacontent, services and applications. Image archiving and retrievalservices, video and music downloads, GPS and mapping services,subscriber targeted and location based advertising, businessVPNs, and GUI-based applications controlling home entertain-ment and computing resources are only a ew examples o themany services and applications that will drive a virtual explosionin bandwidth requirements over the next ew years.

The backhaul network is typically ill prepared to scale cost eec-tively to meet the resulting growth, and that is a situation thatoperators must change quickly i they are to cash in on the ull

revenue opportunities associated with mobile broadband. Whilethe demand or mobile multimedia services is unquestionablystrong, there are some very signifcant challenges which opera-tors must overcome to successully commercialize them.

The Cost Challenges o MobileBroadband ServicesThe amount o revenue that multimedia services generate perbit o network bandwidth tends to be considerably less than therevenue/bit generated by mobile telephony. And this problem iscompounded by the act that mobile broadband services are nowusing signifcantly more bandwidth than mobile telephony. For

this reason, achieving a proftable roll out o mobile broadbandservices requires that the total cost o ownership per bit o trans-port must decrease signifcantly. Since neither leased lines nortraditional microwave is able to support a strong business caseor scaling 3G and 4G multimedia trac. Clearly a more cost e-ective backhaul solution must be ound. Ethernet will necessar-ily be a key part o a cost eective solution, but mobile operatorsalso need to determine how best to achieve synchronization andsupport multiple generations o 2G, 3G, and 4G.

Evaluating the TechnologyChoices or BackhaulLeased lines and the installed base o legacy microwave do

not scale cost eectively, and though the hybrid or packetmicrowave solutions that are succeeding them provide greaterscalability, they are still subject to spectrum constraints, tovarying link engineering rules on a city by city basis, and to

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What Operators Really Needin a Backhaul Solution

In addition to ecient and scalable transport, low latency, andaccurate synchronization, operators also need backhaul solutionsthat maximize the synergies across access and aggregation in thebackhaul network to minimize operations costs, and they needtechnologies that can eectively complement the toolkit o accessmethods they will utilize to best address the backhaul needs o thevarious classes o cell sites that exist in their network.

What operators really need or backhaul is massive scalability, lowlatency, accommodation o complementary backhaul technolo-gies, and operational synergies across the access and aggregationnetwork wherever possible.

Fiber is emerging as the media o choice where it exists or canbe extended cost eectively, and thanks to the growing FTTH

reduced throughput due to atmospheric attenuation whenadaptive modulation is used. Many operators do not have PONassets to leverage, and even those that do typically fnd that

leveraging these assets can help them address only a percentageo backhaul requirements. PWE3 aggregation devices introduceineciencies due to encapsulation, require careul engineering toensure consistent synchronization, and do not support multiplesynchronization streams to a base station.

The use o fber or backhaul makes increasing sense now as thebackhaul network begins to scale -particularly when coupled withan innovative and cost eective WDM solution that leveragescost optimized active and passive technologies to provideexibility, scalability, and serve in both a metro aggregation roleand provide access to the cell site.

Figure 2 shows some o the pros and cons o various backhaultechnologies leveraging copper and fber-based access media.

Access Media Technology Advantages Disadvantages

Copper-based

Leased lines Stable synchronization

High availability

Installed base

"N x" scalability model

Expense compared to multimedia service

revenues/bit

DSL Sweats existing assets

Immediate availability

Less scalable

Less supportive o synchronous peer to peer

trac

Mismatch with DSL oversubscription model

Suited or access only

EFM bonded copper Niche technology

Leverages spare pairs o copper

Consumes large amounts o existing copper

Perormance varies with copper plant quality

No business model when special builds o copper

pairs / new copper is required


Wireless-based

Legacy microwave Reliability

Known quantity

Spectrum availability and cost

Varying network availability

Ineciency o "daisy chains"

Per-city engineering rules

Line o site requirements

Hybrid and packet microwave Reliability

Known quantity

More ecient aggregation

Better scalability

Adaptive modulation or enhanced availability

Spectrum availability

Spectrum cost

Varying weather-dependent network capacity

Per-city engineering rules

Line o site requirements

Fiber-based

GPON Sweats existing assets where available

Passive operations model

Not justifed or use where not already deployed

or FTTH/FTTC

Less exibility in native transport o TDM and

Ethernet

Not supportive o multiple synch streams per

connection


WDM PON Highly scalable

Supports long distances

Immature technology

Relatively costly solution

Best suited to niche applications

PWE3 Aggregator Competitive cost

Support or 2/3/4G

Encapsulation overhead

Complex adjustment to achieve synch accuracy

Inability to support multiple synch streams

Transmodes iWDM Supports native TDM and Ethernet

backhaul

Supports multiple synch streams

Unparalleled scalability

Operations synergies due to use in both access

and aggregation backhaul network and con-

verged fxed/mobile networks

Active and passive WDM solution

components

Not as cost eective or some smaller sites in

the network

Source: TSP

Figure 2. The advantages and disadvantages o copper and fber-dependent backhaul technologies


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Components o The Transmode Multi-Service Mobile Backhaul SolutionTransmodes Multi-Service Mobile Backhaul Solution is com-prised o both Layer 1 and Layer 2 technologies. At Layer 1,Transmodes Multi-Service Muxponders provide transparentand synchronized transport o multiple STM-1/OC-3 signals

and GbE signals over a single line interace. As an alternative,Transmodes Layer 2 Ethernet Muxponder (EMXP) supports GbE,10 GbE and synchronous Ethernet. In the Multi-Service MobileBackhaul solution multiple GbE signals, each with its own inde-pendent clocking source, can share the same line signal -

a distinct advantage over 10 GbE solutions where all constituentGbE ows must clock o the same synchronization source.

There are two major components to Transmodes solution,the Access Solutions and the Hub Solution.

The Access Solution

There are three Access Solution Options: a low capacity node anda high capacity node, which can be cascaded or greater capacity,and an Ethernet Access node. Each o the Access Solution optionsis a compact 1U node with two line interaces enabling 1+1 protec-tion. The Access Solution options are shown in Figure 6 below.

Figure 5. The Transmode Multi-Service Mobile Backhaul Solution

Figure 6. The Transmode Multi-Service Mobile Backhaul Access Solutions

Low Capacity Node High Capacity Node Ethernet Access Node

TDM Interaces 8x E1/T1 16x E1/T1* NA

Ethernet Interaces2x 100/1000-BaseT

+ 2x FE/GbE

4x 100/1000-BaseT

+ 4x FE/GbE

4x GbE

Size 1U 1U 1U

Line interaces (confguration dependent on collected

capacity)

2 line interaces

2.5 Gbps or 4 Gbps (confguration dependent on

collected capacity)

2 line interaces

2.5 Gbps or 4 Gbps (confguration dependent on col-

lected capacity)

Protection interaces 1+1 protection 1+1 protection 1+1 protection

*The High Capacity Node can be cascaded to provide up to 32 E1/T1s over a single line interace.

The Hub SolutionThe Hub Solution is a plug-in unit that is inserted into the chassiso a Transmode TM-3000, which maps E1/T1 signals into STM-1/

OC-3 or aggregation and transport up to the appropriate controlpoint. The capabilities o the Hub Solution are shown in Figure 7.

Figure 7. The Transmode Multi-Service Mobile Backhaul Hub Solution

Hub Unit Type E1/T1 support Ethernet support Special Features

Plug in to the TM-3000 or

TM-301 chassis

Maps E1/T1s into STM-1/OC-3 uplinks Ethernet signals are provided synchronization and

are data transparent or transport over Layer-1 or

a synchronous Ethernet Network

Two hub nodes can be interconnected to enable better

utilization o the STM-1/OC-3

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Benefts o the Transmode Multi-Service

Mobile Backhaul SolutionTransmodes Multi-Service Mobile Backhaul Solution providessignifcant scalability or both E1/T1 and Ethernet backhaultrac, and supports each o these types o trac natively. Onebackhaul acility supports TDM and Ethernet with a simple andeective approach similar to that used by hybrid microwave.Any mix o TDM and Ethernet trac can be supported, withno penalty in terms o the total bandwidth available on thebackhaul acility regardless o the trac mix. Operators canuse proven TDM timing and synchronization while also carryingEthernet trac natively.

TDM trac is transparent and never queued; delay and jitterremain constant or the utmost in deterministic perormance.

E1/T1 and Ethernet signals are multiplexed and transportedwhile maintaining ull synchronization transparency. This Layer-1multiplexing technique ensures the highest quality clock signal byundamentally eliminating latency and jitter on Ethernet trac,and multiple Ethernet signals, each with its own high-qualitytiming reerence, can share the same wavelength. Both theT1/E1and Ethernet trac carry a physical-layer synchronization signalby transporting a Stratum clock with this approach, ensuringa synchronization signal that meets E1 and T1 standards, whileundamentally eliminating jitter and bit-error multiplication.

The cost synergies o using a single transport acility or allbackhaul trac are realized, and there is no need to physicallyreconfgure the network as bandwidth requirements or the

trac mix change. Because Transmode does not encapsulateTDM within IP packets or Ethernet rames or map Ethernet intoTDM, the ineciencies and associated delays o doing so areeliminated. The Transmode solution can complement or supportthe use o pseudowires at the operators discretion, and its abilityto handle Ethernet in native ormat enables backhaul capacity toscale to multiple GbEs when needed.

The Transmode Multi-Service Mobile Backhaul Solution helpscarriers control both capital expenditures and operationsexpense as they continue to scale to meet their own backhaulrequirements or the backhaul requirements o their wholesalecustomers. The exibility it provides in terms o scalability andnative support or both TDM and Ethernet means carriers are

reed rom the need to try and accurately project backhaulbandwidth requirements and trac mix ar into the uture.

ConclusionBandwidth requirements are exploding due to multimedia mo-bile broadband services, and mobile operators need a more costeective and scalable solution or their backhaul networks as aresult. Transmode, a leader in developing cost optimized carrierclass WDM solutions, provides the answer with its Multi-ServiceMobile Backhaul solution. Providing native transport o bothTDM and Ethernet trac, supporting multiple synchronizationstreams over a single wavelength, and oering robust supportor the stringent perormance, QoS, and stringent synchroniza-tion requirements o todays mobile backhaul networks, theTransmode Multi-Service Mobile Backhaul Solution supports avariety o requirements cost eectively or network-wide appli-cability spanning both cell site access as well as metro aggrega-tion requirements, and can also play a role in converged fxed/

mobile networks aggregating other trac rom DSLAMs or OLTsto create additional operations synergies.

Transmodes Multi-Service Mobile Backhaul Solution is playingan important role in helping a growing number o operatorswith mobile networks worldwide optimize their mobile or fxed/mobile backhaul network to acilitate an optimal migration pathto an Ethernet or all-IP backhaul network and enable an acceler-ated, trouble ree and proftable introduction and ramp up onew revenue generating multimedia services.

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Solving the Mobile Backhaul challenges