optimizing radio technologies

As operators roll out LTE 4G networks, WCDMA/HSPA 3G technology is rapidly shifting from the front

of the mobile broadband evolution into a mobile broadband vehicle for all. At the same time, GSM

continues to be an attractive proposition for entry-level mobile subscribers and machine-to-machine

applications, while offering the world’s broadest coverage.

As subscriber numbers and traffic levels continue to rise, operators need to take a holistic view of

their spectrum resources and balance investment across all technology generations. This way, they can

make best use of resources to maximize user experience and revenue across 4G, 3G and 2G networks.

ericsson White paperUen 284 23-3195 Rev B | March 2015

Mobile broadband for all

MoBiLE BRoADBAnD foR ALL • GRoWTH ACRoSS THE BoARD 2

Growth across the boardWhile new LTE rollouts hit the headlines, WCDMA/HSPA continues to enjoy huge subscriber

growth and is expected to continue this expansion for many years to come. At the end of

2014, WCDMA/HSPA subscriptions were growing at 60 percent year-on-year, and the

technology is expected to cover 90 percent of the world’s population by 2020, when it will

serve some 4.5 billion subscribers [1], as shown in figure 1. At the same time, many

subscribers and machine-to-machine (M2M) applications still rely on GSM connectivity,

thanks to its wide availability and the low cost of handsets and chipsets.

The big question for operators is how to satisfy demand for GSM and WCDMA/HSPA

efficiently, maintain a high-quality user experience and maximize their revenue potential as

they roll out LTE 4G networks.

Given WCDMA/HSPA’s key role in delivering mobile broadband to the mass market,

operators will need to find ways of building and enhancing their 3G coverage and capacity.

Therefore, 3G will offer an excellent mobile broadband experience both in its own right, and as

a complement and supporting technology to LTE 4G. This is especially important as a growing

number of subscribers become accustomed to mobile broadband and will be more inclined to

switch service providers if they are not getting the performance they expect.

A WCDMA/HSPA network that can handle smartphone users’ demands well outside LTE

coverage may also enable operators to sustain a premium LTE consumer experience.

While GSM is currently the dominant ‘everywhere standard’ for seamless mobility coverage,

WCDMA/HSPA is increasingly adopting this role, especially for voice.

A recently published report found that the top reason for continuing to invest in 3G

networks (cited by 73 percent of operators) was to support growing voice traffic. Another key

driver was 3G providing an important complement to LTE (cited by 47 percent of

respondents), while 40 percent cited the more cost-effective 3G device supply as a reason for

continued investment in 3G networks [2].

operators need to balance their investments across all technologies to make the most

efficient use of available radio spectrum, while delivering more consistent network

performance and high-quality user experience everywhere – leading to improved revenue.

figure 1: Global mobile subscriptions by technology.

MoBiLE BRoADBAnD foR ALL • SUBSCRiBERS DRivE TECHnoLoGy CHoiCE 3

Subscribers drive technology choiceWCDMA is the predominant mobile broadband technology in use today. A major factor in

WCDMA’s success is the diverse ecosystem of affordable, high-capability WCDMA/HSPA

smartphones that support all current applications – an application suite that is still growing.

one reason for this success is the falling average selling price of WCDMA/HSPA

smartphones, which has dropped dramatically over the past few years and is expected to

continue to drop to below USD 50. This enables large populations to access many more

applications, like social networking and financial services.

GSM continues to thrive as an affordable technology for entry-level phones and M2M

applications.

it’s all about affordability

As economies of scale develop, device prices for LTE-HSPA smartphones are also falling, but

the prices are coming down from higher levels, and it will be some time before prices reach a

level that is appropriate for the mass market. There will be a large number of WCDMA/

HSPA-only capable smartphones that will rely on the mobile broadband performance of the

WCDMA/HSPA network.

WCDMA/HSPA subscriptions are growing, and the market for WCDMA/HSPA smartphones

is picking up pace, especially in the entry- (USD 36-99) and mid-level (USD 100-190) price

bands, as shown in figure 2. The market for LTE smartphones is taking off in the high-end

(USD 191-299) and premium (USD 300-plus) segments, and is beginning to experience growth

in the mid-level price band.

Put simply, handset affordability is a key factor for most subscribers. This is why mass-

market mobile broadband is being driven by WCDMA/HSPA-capable smartphones in many

parts of the world, and will continue to be for some years to come.

figure 2: Smartphone technology choice is driven by price.

MoBiLE BRoADBAnD foR ALL • SUBSCRiBERS DRivE TECHnoLoGy CHoiCE 4

good app coverage, everywhere

Although LTE coverage is growing quickly in urban, suburban and rural areas in many

countries, there are still several places where WCDMA/HSPA will determine consumers’

smartphone experience over the next three to five years and beyond, as the coverage

comparison in figure 3 shows [3]. LTE also drives ever higher consumer data usage, which, in

turn, spills over to WCDMA/HSPA networks, driving an increase in 3G traffic where LTE has

been rolled out. Subscribers will be looking to get the best mobile broadband performance

they can, everywhere they go, whichever technology they are connected to.

traffic flows from lte to wcdma/hspa

Even when subscribers are making use of LTE coverage, they are frequently moved from LTE

to WCDMA/HSPA during periods of high LTE loading or during voice calls, as illustrated in

figure 4. in effect, many LTE subscribers will have their mobile broadband experience

delivered by WCDMA/HSPA networks that need to handle higher loads than before, often with

fewer carriers as a result of refarming to LTE.

in LTE networks that provide relatively complete coverage, there are still a number of

coverage-related reasons for LTE devices to be shifted to WCDMA/HSPA. Generally, the LTE

figure 3: World population coverage by technology.

figure 4: Traffic flows from LTE to WCDMA/HSPA.

MoBiLE BRoADBAnD foR ALL • SUBSCRiBERS DRivE TECHnoLoGy CHoiCE 5

fDD variant provides greater coverage than the TDD variant. Devices in an fDD system

transmit continuously, which enables them to achieve cell edge rates further from the base

station. Devices in a TDD system transmit periodically (half or one-third of the time compared

with fDD), which means they cannot achieve comparable cell edge rates as for fDD at similar

distances (there is an estimated 5dB advantage for fDD in today’s LTE networks).

Where operators want to offer premium services over LTE, it may be necessary to offload

users to WCDMA/HSPA, where a substantial proportion of subscribers can be served

perfectly well.

voice connections will also contribute to a large flow of LTE-capable devices to WCDMA/

HSPA, as relatively few of today’s LTE handsets support voice natively.

The result is that operators must invest in their GSM and WCDMA/HSPA networks to ensure

they deliver the best possible app coverage for the largest number of people. not investing in

GSM and WCDMA/HSPA will threaten subscriber retention and increase churn if app

coverage quality does not meet subscriber expectations as the mobile broadband market

continues to grow, LTE coverage expands and 5G arrives on the scene.

MoBiLE BRoADBAnD foR ALL • SHAPinG UP ACRoSS THE GEnERATionS 6

Shaping up across the generationsEven in markets where LTE 4G networks have been rolled out, users still need to move

between 3G and 4G coverage, not just for voice but also for data. Many markets will have 4G

coverage ‘islands’ for the foreseeable future. it is important that mobile broadband users’

experience does not fall dramatically as they move from 4G to 3G. There will also be many

mobile broadband subscribers who do not own 4G-capable devices for years to come.

To protect and enhance their reputation and revenue streams, operators need to ensure

their 3G networks are delivering the best possible performance in the most efficient way. The

improvements can be dramatic: field measurements have shown a fivefold difference in

capacity between the worst-performing and best-performing WCDMA/HSPA networks.

new radio features and improved network optimization capabilities mean it is now relatively

straightforward to configure a modern WCDMA/HSPA network to deliver a smartphone

experience not far off that provided by a state-of-the-art LTE network.

As well as ensuring good WCDMA/HSPA performance through implementing the right features

and configurations, operators can also optimize WCDMA/HSPA usage by considering smartphone

functionality and applications, capacity, coverage, feature evolution, spectrum refarming and

transport strategies in a multiband, multilayer and multi-access technology context.

making 2g as efficient as possible

GSM networks still serve more than 4 billion (GSM-only) subscriptions while offering 95

percent global population coverage and by far the lowest-cost handsets on the market. They

handle at least 80 percent of voice traffic in developing markets, as well as dominating the

M2M market. This means the vast majority of operators need a way to look after their GSM 2G

networks as they roll out and expand mobile broadband coverage and capacity in 3G and 4G

over the coming years.

for most operators, a one-off investment in multi-standard radio technology, with the latest

automated configuration and optimization features, provides an attractive way forward. By

deploying multi-standard radios, baseband units, transmission and controllers, operators can

spread their capital and operating costs across all generations of radio technology and shift

traffic handling capacity to the technology that needs it. Hardware efficiency and energy

efficiency are both enhanced.

The latest self-organizing networks technology, with features like Automatic neighbor

Relations, helps operators automate their 2G networks and keep them running at peak

performance with minimal manual intervention. This will be a key issue as GSM radio expertise

becomes a rarer commodity.

With an efficient, high-performance and future-ready GSM network, operators will be in a better

position to refarm much of their 2G spectrum to 3G to meet the growing demand for mobile

broadband. This ‘thin layer’ GSM network offers a very efficient way of handling 2G voice and

M2M traffic until such time as 3G and 4G networks are ready to take the load. in many markets,

3G is already starting to become the radio technology of choice for delivering seamless coverage

(especially for voice), and this trend is likely to continue for some years to come.

MoBiLE BRoADBAnD foR ALL • SHAPinG UP ACRoSS THE GEnERATionS 7

maximizing 3g performance

Live network experience shows that simply getting the existing WCDMA/HSPA 3G network

into shape, through tuning, optimization and introduction of the latest features, can boost

traffic capacity by as much as 100 percent (using the same spectrum). Evidence from existing

operators also demonstrates that when subscribers have access to faster, more responsive

networks, their data usage increases – providing a recurring revenue boost.

Typically, the changes that many operators need to make to their 3G networks include

adjusting parameter settings, activating existing features in the right way, and introducing

some newer features. for example, they can prioritize voice while allowing users to stay

connected to 3G (and not fall back to 2G). They can introduce powerful HSPA enhanced

uplink functionality to improve mobile broadband performance, make radio parameters

consistent across all sites, and activate important smartphone features like Enhanced Uplink

forward Access Channel, High Speed forward Access Channel and Continuous Packet

Connectivity – as described in a recent joint Qualcomm–Ericsson white paper [4].

By introducing newer WCDMA/HSPA capabilities, such as multi-carrier technology,

operators can substantially increase the throughput offered by 3G networks. for example,

three-carrier High Speed Downlink Packet Access (HSDPA) boosts downlink speed to

63Mbit/s, while dual-carrier High Speed Uplink Packet Access boosts uplink speed to

11Mbit/s.

making best use of spectrum

Spectrum is a key asset for operators, so it makes sense to use all available spectrum to

maximize mobile broadband performance for all users.

operators who are able to refarm a portion of their low-band 2G 900MHz spectrum to 3G

can use these frequencies to greatly improve cell edge and indoor performance compared

with 2100MHz-only coverage. When WCDMA/HSPA has been rolled out in low band spectrum

everywhere, operators could choose to switch off inter Radio Access Technology handover to

GSM: WCDMA/HSPA offers a much better smartphone experience than GSM.

To further improve mobile broadband experience, multi-carrier HSDPA should be

implemented everywhere. This will provide a doubling of user speeds throughout the whole

cell and up to 30 percent capacity increase due to improved spectrum utilization (compared

with single-carrier mode).

over time, operators could choose to refarm increasing amounts of spectrum to LTE 4G,

while maintaining seamless WCDMA/HSPA 3G coverage in certain bands (900MHz or

2100MHz, or both).

8

As they increase the spectrum allocated to LTE, operators would be well advised to keep at least

20MHz of spectrum for WCDMA/HSPA (low and high bands), with at least 5MHz (preferably

10MHz) allocated in a low-band frequency, to secure the best mobile broadband experience.

The target split of spectrum between 2G, 3G and 4G might look like that shown for a

European operator in figure 5 (it is a similar picture for operators in other parts of the world,

but with differences in actual frequency bands).

multiband, multi-standard, multilayer

Many operators already have three technologies (GSM, WCDMA/HSPA and LTE) in

commercial service, and the future is all about adding more bands for capacity and the

growing demand for mobile broadband. Most operators will have at least five bands deployed

in the near future.

To get the maximum performance from each band, most or all of the bands will be

multilayered (combining macro and small cells in a heterogeneous network). This will make

features like coordination between the bands, layers and standards vitally important, with a

strong need for carrier aggregation and heterogeneous management features.

By introducing performance-enhancing features in their 2G and 3G networks, and ensuring

that existing 3G devices are directed away from 2G and onto 3G networks as much as

possible, operators not only enhance user experience and revenue, they also make the most

efficient use of their spectrum and infrastructure investments.

MoBiLE BRoADBAnD foR ALL • SHAPinG UP ACRoSS THE GEnERATionS

figure 5: Target spectrum allocation in a multiband, multi-standard and multilayer context for a typical

European operator.

MoBiLE BRoADBAnD foR ALL • ConCLUSion 9

ConclusionLTE adds new value for mobile operators in terms of its superior network capacity and higher

throughput needed for high-performance mobile broadband services (especially video). However,

WCDMA/HSPA is a mature, but still developing, technology that offers cost-efficiencies,

established voice support, mass-market appeal and coverage advantages that means it will offer

an efficient delivery vehicle for excellent smartphone experience for years to come.

To maintain and grow market mobile broadband share, operators need to carefully balance

their investments across GSM, WCDMA/HSPA and LTE over the next three to five years. This

way, they can continue to provide GSM coverage as efficiently as possible, and ensure WCDMA/

HSPA offers the best possible mobile broadband experience – not only as a high-quality

complement to LTE, but also as a way of delivering mobile broadband coverage to very large

populations for the first time.

With a suitable investment, WCDMA/HSPA will complement and support LTE (and not just be

a fallback), and will enable operators to maximize revenue by delivering good network performance

and a seamless experience across their 3G and 4G networks.

MoBiLE BRoADBAnD foR ALL • REfEREnCES & GLoSSARy 10

References[1] Ericsson, november 2014, Ericsson Mobility Report, available at: http://www.ericsson.com/res/docs/2014/

ericsson-mobility-report-november-2014.pdf

[2] Current Analysis, february 2015, 3G Wireless investment Motivations – Why do mobile operators continue to

invest in 3G wireless infrastructure?, available at: http://www.currentanalysis.com/d/2015/3GWiM/

[3] Ericsson, november 2014, Ericsson Mobility Report, op. cit.

[4] Ericsson & Qualcomm, february 2015, White Paper: 3G smartphones – optimizing user experience and

network efficiency, available at: http://www.ericsson.com/res/docs/whitepapers/wp-3g-smartphones.pdf

© 2015 Ericsson AB – All rights reserved

GLOSSARYcs circuit-switched

hsdpa High Speed Downlink Packet Access

m2m machine-to-machine

td-scdma time division synchronous code division multiple access