LTE in 2014: Operators will reap benefits of carrier aggregation

ENGLAND, UK: LTE continues to make an impact on the mobile networking landscape, and 2014 will mark the arrival of new features and capabilities that show just how capable the technology is in meeting mobile broadband requirements for a wide range of mobile operators.

LTE will make the spectrum-rich richer, and the spectrum-poor just a little better off
In 2014, more operators will deploy LTE-A carrier aggregation (CA), including operators doing initial LTE deployments. CA benefits operators with multiple spectrum positions, those with small pieces, and particularly operators that are combining acquired networks.

The initial focus is on higher-speed services, but we expect more deployments of 5+5MHz carrier aggregation as emerging markets deploy LTE in 2014.

Early testing of carrier aggregation is enabling operators to bind separate spectrum channels together to create larger channels and faster wireless services, and reduce opex and capex costs from running multiple networks. SK Telecom and LG Uplus in South Korea are offering commercial LTE-A carrier aggregation services supporting speeds of up to 150Mbps, and EE in the UK has demonstrated near-300Mbps LTE-A service in London.

Larger network operators such as AT&T, Sprint, Telefónica, Verizon and Vodafone, as well as operators holding multiple spectrum positions such as EE, T-Mobile, Telstra, will be early implementers of carrier aggregation.

Band fractionalisation will be less of an issue thanks to broad device support
LTE band fractionalisation will come to an end in 2014. Despite early and well-publicised concerns regarding the number of different bands supporting LTE (25 for FD-LTE and 11 for TD-LTE), the market has - as we had expected - focussed on five bands for FD-LTE (700MHz, 800MHz, AWS (1.7GHz and 2.1GHz), 1.8GHz and 2.6GHz) and four for TD-LTE (2.3GHz, 2.5GHz, 2.6GHz and 3.5/3.6GHz).

Devices are able to support approximately six bands (the new iPhone 5S/5C support 17 via different models), thus providing room to support both ‘local' bands as well as the more commonly used ‘global' bands. 2.6GHz and 1.8GHz are early candidates for LTE roaming, but neither band is in use in North America.

The rapidly expanding international base of support for the APT700 plan is making North America an ‘LTE island', but device support for one of the ‘international bands' alleviates this problem. One area that remains potentially problematic for operators is support for LTE-A, which we expect will largely be a local phenomenon and not available for roaming services.

VoLTE will emerge as a (limited) market service
VoLTE is unlikely to make a significant impact in 2014 because few countries will have the breadth of network needed for useful service (Japan and the USA are the notable exceptions). However, we expect that both countries will launch VoLTE services, with circuit-switched fallback (CSFB), as a precursor to more-advanced services including RCS and other voice-over-data-enabled services.

Other countries with concentrated users such as EE in the UK, Telstra in Australia may also launch VoLTE with HD Voice as a competitive differentiator. Voice support for most operators has to include a ‘fallback' solution for non-native VoLTE calls, or calls in areas where LTE coverage is lacking or limited.

We also expect carriers will move more slowly towards Single Radio Voice Call Continuity (SRVCC) because the complexity of that solution demands a simplification by the equipment vendors for widespread implementation.

South Korea is the world leader in VoLTE penetration, largely because of the ability to offer 100% LTE network coverage - all three national carriers have embarked on aggressive (and highly competitive) network build-outs. SK Telecom announced that it had more than 4.5 million VoLTE users as of June 2013 and it leads the South Korean market in terms of VoLTE subscribers.

For operators to rely on LTE for their voice coverage, complete network build-outs are required. Verizon Wireless's network, the USA's largest LTE network, had about 303 million people covered in September 2013, out of a total population of 317 million.

South Korea is proving to be the LTE technology ‘test-bed', with both LTE-A with carrier aggregation and VoLTE in commercial use. Devices supported include the Samsung Galaxy S3 and S4. However, VoLTE still appears to be a future application in all markets except South Korea, as early LTE MNOs use both dual radio (supporting voice on a separate call) and CSFB for early voice support.

Mobily announced in May 2013 that it had worked with partner Huawei and completed tests of VoLTE and enhanced Single Radio Call Continuity (eSRVCC). These are probably the first such tests in the Middle East and North Africa.