Telecom Insight Guide_Building 4G Wireless Network

8/2/2019 Telecom Insight Guide_Building 4G Wireless Network

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Building the4G wireless networkExploring LTE architecture and services drivers

In this our-part Telecom Insights guide,

Tom Nolle takes a detailed look at how

4G Long-Term Evolution (LTE) architecture

and technology planning and deploymentdecisions should be infuenced by LTE

service opportunities in various wireless

markets. It also looks at why carriers need

to evolve their metro network inrastructure

toward an Evolved Packet Core or wireless

broadband and how changes in metro

network technology and operations are

being driven by these issues.

Table o contents

02Key 4G LTE architecture

and opportunity drivers

05Deployment or peak

perormance and

operations

084G LTE means three

class o service issues

11Greeneld and

browneld network

design


2/12

02 l Building the 4G wireless network

Few people in the mobile industry dispute the inevitability o 4G Long-Term Evolution (LTE), but the timing and

the nature o deploying LTE network technology and inrastructure is less certain. Rather than a one-size-ts-all

approach, 4G LTE architecture is being determined by the specic competitive and opportunity drivers that provide

the impetus or operators to shit to LTE. The solutions vary because o signicant dierences in wireless markets.

The most credible driver or deploying 4G LTE architecture, however, is the market-wide shit rom a voice-driven

wireless revenue model to a ocus on non-voice services. That is, broadband data and video. Operators worldwide

have been oering unlimited-usage models, and competition is driving down mobile per-minute prices. At best,

voice ARPU is capped and its likely to spiral down over the next ve years. Short message service (SMS) is under

similar pressure, so data and content services that include video are the hope o the uture.

The most eective mechanism or promoting mobile data services has been the growth in smartphone use. The

Apple iPhone made smartphones a market phenomenon, spawning a host o competitive models and the entry

o Googles open-source mobile Android operating system as a general competitor. To create Android, Nokia andIntel which both previously oered their own open-source Linux smartphone platorms agreed to combine their

programs to boost market interest. Proving the point, industry statistics point to smartphones making up a third

o all handset sales within a year.

Key 4G LTEarchitecture and

opportunity drivers

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


3/12


In the US alone, smartphone use has clogged cells and entire metro areas, aecting the credibility o smartphone

data services and the services oered via traditional handsets. Smartphones also accentuate the competitive benet

o higher mobile data speeds, and the success o smartphones will accelerate 4G LTE architecture deployment.

The wireless market orces driving 4G LTE architecture deployment are many and complex. Heres a brie overview

o the main orces that operators should consider.

First are third-party developer programs. A theme related to the smartphone is the explosion o interest in third-

party developers, applications and application stores. Every smartphone vendor now has one, and the GSMA aGSM-ocused industry group announced an initiative to create a uniorm application ramework and store across

two dozen operators, and membership is growing. Phone applications are also a main ocus o Microsots new

mobile architecture, Windows Phone 7.

Second, apps provide an assist. Applications are a natural pairing with smartphones because a general-purpose

browsing unction is o limited value to users, owing to the small screen and the diculty o manipulating the

device to navigate websites while mobile. Applications can draw online inormation, but they package the user

navigation in a way consistent with mobile device and user constraints. Applications dont require 4G LTE services,

but most operators are reluctant to make substantial investments in 3G-based application stores and service layer

architecture or ear that the success o the investment could overstress 3G networks.

Taking the place o wireline broadband. In rural areas and developing economies, 4G LTE network architecture

evolution is being stimulated by the need to oer wireless services as an alternative to xed-wire broadband

services. Many developing countries depend on mobile phone services because they lack xed-line inrastructure.

In these markets, it would be unproductive to attempt to deploy wireline broadband given the low economic

densities available to justiy it. LTE networks oer an enormous advantage in these areas by providing a wireless

service that can be used to support xed broadband access in selected homes and businesses rom the same

inrastructure that supports traditional mobile services. This driver is particularly valuable in areas that depend on

tourism because internet access is increasingly a baseline requirement or travelers.

Forces that drive deployment

Third are regulatory issues. Public and regulatory pressure to include broadband access in universal service subsidies

or to und rural broadband widens the scope o interest in LTE as a xed/mobile combination. When LTE architecture

is paired with requencies that oer reasonable range, it can serve a airly large geography economically while

supporting both xed sites and mobile services. As beore, this dualism oers a better return on inrastructure and

better use o scarce spectrum resources. Wimax, the other 4G technology, is also suited to the rural market, but

LTE is generally viewed as a more suitable strategy because it is an evolution o 3G wireless and is more versatile

where mobile phones and wireless broadband coexist.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


4/12


Fourth, the mobile appliance explosion. A nal critical driver or LTE is the mobile appliance explosion, rst seen

in the use o network-enabled e-book readers and now expanding to new-age tablet appliances. These devices

are emerging as the core o a new series o business models based on delivering content to users who are less

mobile and use the device rom a variety o xed locations as opposed to using it while moving, literally.

Operators expect that this migratory-use behavior model will create considerable demand on cells in locations

where people sit and socialize classic hospitality sites.

Fith, supporting mobile users with dierent usage patterns. Some network operators ofoad 3G network trac

using hotspots and Wi-Fi to support these users, but others preer to keep their users on their own cellularnetworks using emtocells. Among the advantages o emtocell technology is that it can be applied to either 3G

or 4G/LTE networks. But given the inevitability o LTE architecture deployment, most operators say they plan to

deploy emtocells as a part o their overall LTE program. Femtocells can also be used in the home to ensure that

LTE customers have good service even during the period o transition rom 3G.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


5/12


Finally, there is wireless voice complexity. Many operators also ace a cost-side driver or LTE architecture the need

to modernize voice services around voice over Internet Protocol (VoIP). Because 3G voice is based on time-division

multiplexing (TDM), as most wireline voice services are, the t between the two has been good up to now. As the

wireline voice switching plant ages, it becomes more dicult to justiy reinvesting in the technology, given the

sharp downward trend in voice pricing and the increased competition rom internet voice services like Skype. I

wireline voice is to shit to VoIP, then wireless voice should as well.

The interest in moving to a lower-cost VoIP service model has accelerated since 2008, partly because o global

economic conditions and competition rom over the top (OTT) players like Skype and Google that has become

more intense. While ew operators plan a ork-lit voice inrastructure upgrade, most expect that they will be

moving away rom the TDM model over the next ve years, and a decision to shit to packet voice or mobile

services would acilitate this migration. Many operators are looking at creating a parallel VoIP model supporting

both mobile and wireline users while gradually phasing out the older voice inrastructure as it ages.

Operators gain the advantage o higher data rates per cell rom 4G LTE, larger customer capacity per cell, and more

ecient use o backhaul and metro connect inrastructure or services that are increasingly data-dominated. The

current explosion in smartphone and mobile appliance interest makes it clear that the markets will quickly stress

the capacity o 3G networks and that urther 3G investment will be problematic i there is any risk that competitorswill leaprog to 4G. Because that risk exists in nearly every developed wireless market, there is little chance that a

given mobile operator will not conront at least one o these LTE drivers in its service area in the near uture.

Deployment or peakperormance and operations

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


6/12


Wireless 4G LTE inrastructure has a three-layer network structure where components perorm a set o structured

missions that are independent but cooperate with the other LTE network layers. LTE technology diagrams clearly

show this structure that includes the radio access network, the control layer and the Evolved Packet Core (EPC). But

in the real world, network planners oten have to contend with pressures that operate not on LTE inrastructure as

a whole but on a component that represents only part o a specic LTE network layer.

Beyond the physical LTE network, most operators divide their organizations and activities so responsibilities or the

radio access network can be separated rom tower interconnection or rom service management. A critical task or

operators is to plan LTE network layers independently without losing the cooperation.

In a practical sense, LTE planning starts with the radio access network. Ideally, operators should consider deploying

sotware-dened radio technology capable o supporting both 3G and 4G services in the spectrum bands available

as soon as possible to make their radio access network technology LTE-ready. When new cells are added or when

cells are modernized, this sotware-dened radio platorm investment can pay signicant dividends in ensuring

that radio lie is maximized.

Radio access network planning or LTE must also consider target services, target locations and migration needs.

Nearly all LTE deployments will evolve rom existing 3G services, and there is a temptation to think o LTE as

replacing or paralleling 3G on a per-cell basis, which would create planning problems or the ollowing reasons.

The capacity o LTE cells is higher, and a smaller number o more widely spaced cells may work well i cell capacity

limits arent exceeded.

Early customers or LTE services are probably going to be users who have specialized 4G LTE handsets or appliances

or who have specialized needs. These customers may be more likely to use LTE service in specic locations, so

providing it there rst is important.

Some areas may lack the tower connection and backhaul capabilities needed to ully exploit LTE, thereore providing

acilities there may take time, suggesting that the sites be de-prioritized or now.

LTE network demand may be highly variable through the day owing to the patterns o smartphone or tablet use.

Intelligent antenna technology may be valuable to customize coverage in order to maximize service utility.

LTE service evolution is particularly important, and the question is, what handset capabilities will exist? Almost

every operator with LTE plans will have parallel 3G and 4G services operating or some time to accommodate the

installed handset base and to support existing roaming agreements. Supporting 3G/LTE handsets or new service

customers will ensure that they can use their devices while outside the evolving 4G service area, but it may also

perpetuate the use o 3G. Transition planning or handsets is critical to support transition planning or the radio

network.

Trac management and mobility management are capabilities LTE creates in the next layer the EPC. The EPCbuilds a sub-network within a metro/core inrastructure that extends rom the tower (eNodeB) through the Serving

Gateway (SGW) to the PDN Gateway (PGW) in order to provide connectivity between user equipment and the

packet data network.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


7/12


The portion o metro/core inrastructure within the boundaries o this chain is controlled by LTE, and the associated

service control processes (oten using IP Multimedia Subsystem, or IMS). Maximizing this zone makes mobile

services discretely controllable in terms o quality o service but can also limit inrastructure reuse. Making the zone

smaller (jumping o into the packet data network sooner) will improve overall eciency but limit mobile service

customization potential.

EPC components require service control input

Operators also need to consider how the LTE EPC elements noted above will be mapped to real hardware. Somevendors oer discrete or specialized devices to support these roles, and others use intelligent line cards in switches

and routers. The decision on which hardware to use may be made by deault i the inrastructure to carry LTE trac

rom the towers to the service point has already been deployed and doesnt oer a smart card option, or where

the wireless operator is outside its wireline market area and doesnt own the lower network layers. In cases where

the choice is available, it would be smart to review the capabilities o the integrated smart cards. Normally, these

will reduce capital and operations costs and reduce trac latency by minimizing box-to-box connections.

At the deepest level, where the EPC integrates with existing inrastructure, it is important to review vendor options

or trac ofoad. Smart trac handling at or near the eNodeB can segregate Internet trac rom wireless service

trac and move it immediately onto the best-eort inrastructure used or broadband internet connectivity. That

will reduce trac in the more expensive EPC components and improve service perormance and operations costs.Ofoading is especially critical or internet video trac, which can load the SGW/PGW and the associated tunnels

signicantly.

A nal point in the layer-by-layer review or LTE planning and design is to ensure that all o the components, especially

the radio access network (RAN) and EPC components, properly link with the service control and registration logic.

EPC components require service control input to manage trac routing and to rebuild the connection map or

mobile users. The links must be stable and secure while also being compatible in terms o ormat and interace

standards with the equipment that operators plan to deploy. Specic lab testing is recommended.

Lab testing is a good idea or LTE layer planning in all cases. Operators report that the best approach is to have

two distinct test models: one that represents the nal orm o an evolved inrastructure, and one that represents

the evolution itsel. When the end-state components have been veried in the rst test bed and any longer-term

interoperability issues resolved, the evolutionary test bed can be used to model each stage o deployment to ensure

success.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


8/12


Mobile services are changing ast enough to make planners dizzy, even i they are conned to the core mobile

space where voice continues to dominate.

Competition and the need to harmonize voice planning and inrastructure with emerging non-voice services

(wireless broadband data and video) have totally revamped wireless service provider business models. For example,

who would have believed a ew years ago that operators would allow Skype voice applications on handsets?

The evolution to 4G Long-Term Evolution (LTE) has created three distinct class o service issues that promise to

change wireless operators planning models in the coming decade. While each one is signicant in itsel, they are

almost certain to act together in all major market geographies. The result will be a planning shit in voice services

that drives massive changes in voice inrastructure.

The three issues are the migration o earlier mobile voice services to 4G LTE voice services, migration rom a

supply-side mobile service market controlled by wireless operators to one driven more directly by demand and

outside orces, and the behavioral migration model created by the impact o always-available mobile broadband

on consumer and worker behavior.

Mobile voice migration has two dimensions, one linked to evolving the current radio/handset combination to LTE,and the second to evolving existing TDM-dominated voice services to voice over internet protocol. In both cases,

the problems are the inertia o current services, the capital required and the customer impact o changes.

The eect o wireless voice migration can be reduced i the operators target is largely made up o data devices.

4G LTE means threeclass o serviceissues

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


9/12


In that case, LTE can be deployed almost as an overlay and its ootprint expanded based on growing market

opportunity. Where the goal is a more complete migration to 4G in a shorter timerame, it will be necessary to

accommodate 3G and 4G simultaneously in the radio network. It may also be necessary to support dual-mode 3G/

LTE handsets to provide service to LTE customers who are outside the current LTE ootprint or roaming on other

providers networks.

For the TDM-to-VoIP element o LTE voice migration, operators have a choice o sustaining voice independently

on 3G or as long as the dual radio access network (RAN) is in place. Eventually, though, they will have to

accommodate LTE voice, which is VoIP. The pace o this accommodation may depend on the age o the TDMwireline inrastructure and the pace at which wireline voice can be migrated. Alternatively, operators can explore a

TDM-over-LTE option such as VoLGA (Voice over LTE Generic Access). VoLGA allows operators to perpetuate TDM

switching even in a pure LTE mobile network, but its probably most valuable in managing the 3G-to-4G migration

where there is substantial capex and opex dedicated to the TDM voice plant.

The supply-side/demand-side transition in mobile services is due to the growing infuence o over-the-top

(OTT) players such as Google and to the application stores and smartphones o players like Apple. The act that

smartphones act as internet appliances whose specic behavior is created by developers exploiting web assets has

made the smartphone very responsive to market ads and has in act let smartphones create those ads. Operators

must now address the question o how to oer their own service enhancements on a shorter market cycle without

compromising their long-lived capital assets and operations practices.

Most prospective LTE operators still see IP Multimedia Subsystem (IMS) as their primary voice and connection

services ramework, but its clear that some collateral way o creating web-like applications or smartphones will

be essential i the whole consumer market is not to be ceded to Apple and Google. The path to success lies in a

combination o creating service-layer assets that can be exposed through web interaces, as well as via IMS, and

in creating developer programs to encourage third parties to build services using these tools. Some operators

have taken a lead in these programs, and others are looking to standards bodies and industry groups to create

cooperative communities o operators to broaden support and enhance developer credibility.

Market shit to mobile rst

The nal evolution in services is also linked to the transormation in services being created in the mobile space. Eric

Schmidt, Googles CEO, encouraged developers to ocus on mobile rst, which is a refection o the act that

because mobile devices are constant companions, they are likely to create the user behaviors that will translate into

service opportunities not only in wireless but also in wireline.

Social networks have made the transition rom wireline to wireless, showing that consumer behavior patterns

transcend technology. Many service planners believe that innovative mobile services built to reinorce emerging

network-enabled social behavior will translate in the other direction. Operator plans to use emtocells or home,

hospitality and business networks will create an option to use a mobile device as a universal portal, always available

and always on but integrated not only with the wireless carrier network but also with a home or local network.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


10/12


What links all these service trends, in act, is the symbiosis between mobile services and social behavior. Mobile

calling and SMS services evolved to ll what was primarily a social need. With their availability, users modied

their behavior to exploit the services and created a whole new online culture. The handset market and associated

developer programs are creating a food o new services and potentially new online cultures as well. Because these

new opportunities are driven by social behavior, they will develop and mature quickly and cant be addressed with

traditional long-cycle planning.

Operators dare not miss this wireless evolution opportunity driven by class o service changes. Somehow, the reality

o long-lived capital investment and regulatory oversight must be balanced with the reality o a consumer-driven,social-ad-conscious marketplace. The willingness o operators to not only tolerate but embrace what would in the

past have been seen as OTT competitors is a refection that they recognize the need to move beyond a refexive

deense o traditional markets and into a reasoned exploitation o new opportunity.

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


11/12


Deploying 4G wireless services is an acknowledgement o the transormational mission o mobile service in creating

new opportunities. The term transormational is especially relevant because most 4G deployments will transorm

the business model and network inrastructure o current mobile operators.

For current 3G operators that plan to evolve their services to a 4G Long-Term Evolution (LTE) wireless ramework,

LTE standards and specications dene a longer-term architectural model and provide guidance on how that

evolution can be managed.

One challenge in making wireless evolution guidance practical and useul is that operators oten see LTE as a

greeneld (or new) network opportunity in one geography or application and as a browneld network opportunity

(a transition rom existing inrastructure) in another. Even where operators have 3G inrastructure in place, their

service goals may drive them to create a totally parallel and independent LTE network. Conversely, some new LTE

operators may have to consider interoperability with 3G service providers or roaming and even interoperability

between their own LTE and wireline networks. A harmonious approach to LTE is likely to be helpul to most

operators at some point.

Radio access network (RAN) planning is a requirement or both greeneld and browneld LTE network inrastructure

deployments, but the inormation resources that drive it are dierent. Where 3G services are already deployed, thebest strategy is to use 3G data usage patterns to identiy the locations where LTE is likely to intercept the largest

subscriber interest. When doing this, it is also critical to analyze shits in the pattern through the day and also

through the week. The extent to which demand patterns change may be an indication o the early need or such

things as intelligent antenna systems to change cell coverage to match subscriber mobility.

Greeneld and browneld

network design

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design


12/12


Where there is no 3G data to rely on, it may be necessary to consider basic demographic inormation and consumer/

worker behavior patterns. Most operators report that 3G data usage is highest where customers are at least

somewhat idle in trac, on public transportation or in hospitality locations. 3G data usage is also highest where

the concentration o users includes a high percentage o youth those under age 25. This means that schools/

universities and other natural congregation points or the young are likely to be the early 4G LTE opportunity areas.

LTE mobile backhaul or connectivity is an area where greeneld and browneld network approaches may be very

dierent.

Where 3G services are already in place, the backhaul capabilities or those services arent likely to be directly

upgradeable to LTE or capacity reasons, but rights o way and current inrastructure might be exploited. In an LTE

greeneld network deployment, tower connectivity and mobile trac backhaul to a service point will need to be

created rom scratch. This may also be the case where an operator is adding LTE to a 3G prole that includes many

cell sites that are outside its own wireline network scope.

LTE greeneld network backhaul should consider service and revenue evolution careully in order to avoid getting

too ar in ront o the opportunity because the rst cost is likely to be high and the economy o scale relatively low.

With browneld network upgrades to create LTE backhaul, its probably best to look urther into the uture and

shoot ahead o the duck to ensure that long-term costs are managed, because theres a higher likelihood that

the economies o early deployment will be reasonable where exploiting some o the existing acilities is possible.

Newound fexibility to accommodate trends

In service planning, the 4G wireless browneld network operator will not only have data rom current services

on which to base uture service plans, it will have a customer base to specically target with new LTE services.

Greeneld network LTE providers may lack both o these assets. The service trends created by smartphones and

application stores testiy to the need or fexibility in creating and marketing new services in an LTE world, but there

is a greater need or fexibility in the near term in greeneld applications. The lack o data on services and the lack

o a customer base rom which some degree o market control can be exercised make greeneld providers more

vulnerable to market shits. That is particularly true in a situation where the greeneld network LTE service is being

introduced to compete with existing 3G oerings rom competitors.

Operators believe that LTE deployment issues or browneld network markets are more contained, and the

range o choices or a given technology or service can be constrained by knowledge o the market and the need

to maximize current inrastructure and crat assets. Greeneld LTE network inrastructure, in contrast, provides

greater fexibility in targeting and deployment but also greater risk that the choices will prove sub-optimal in the

near term and threaten early return on investment. In the long term, however, operators believe that LTE network

inrastructure planning will settle on a common model.

Operators also believe that LTE will ultimately transorm metro networking, the role o voice central oces, and the

structure o business and consumer services. This means that the most signicant greeneld/browneld networkissue may be whether the operator is deploying LTE as an adjunct to a common carrier role and a successor to

TDM-based services, or whether LTE is the model o its service present and uture.

TomNolle is president o strategic consulting frm CIMI The content o this Telecom Insight guide is provided by SearchTelecom com

Table o contents

Key 4G LTE

architecture

and opportunity

drivers

Deployment

or peak

perormance

and operations

4G LTE means

three class o

service issues

Greeneld and

browneld

network design

Telecom Insight Guide_Building 4G Wireless Network

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