NEW ANALYSIS: Achieving global economies of scale for LTE remains a challenge, reports Joss Gillet of GSMA Intelligence.

The mobile industry has made good progress in ensuring LTE spectrum harmonisation on a regional basis. However, it has only recently started tackling the challenge of developing an LTE smartphone that works worldwide. Such a device would improve economies of scale for both device manufacturers and operators, while nurturing global LTE roaming and triggering the faster adoption of LTE services.

There are currently close to 200 commercial LTE networks operating worldwide, running on 12 different FDD/TDD frequency bands. About 30% of global LTE deployments are supported by the 1800 MHz band, while the 2600 MHz band makes up a quarter of deployments and the digital dividend bands a further 21%. But the dominance of these existing LTE bands is likely to lessen in the medium to long term as more countries allocate LTE spectrum and additional bands are introduced.

In Europe, LTE spectrum has been harmonised around the 800 MHz, 1800 MHz and 2600 MHz bands. Meanwhile, many markets in Asia and Latin America are adopting the APT700 band plan, and other operators – notably across the Americas – are considering the use of AWS 1700 MHz/2100 MHz band for roaming purposes. These are the key bands that are core to a ‘world’ LTE smartphone today, along with 2100 MHz and 2300 MHz/2500 MHz for TDD.

Nevertheless, handset manufacturers’ choices as to which LTE bands they support have typically been driven by market demand at the domestic or regional level, with LTE smartphones designed to support operators’ immediate spectrum requirements. Samsung chose to support six LTE frequency bands on the Galaxy S4, compared to five for recent devices produced by Apple, Nokia and Huawei.

One large Asian handset manufacturer recently told us that supporting multiple LTE bands is likely to remain a compromise between cost and demand, as defined by the operators’ requirements. The manufacturer went on to say that at present, China Mobile is the operator that requires its OEM partners to support the most complex LTE band portfolio in a single device, with up to 13 bands.

The LTE specifications set by 3GPP, the telecoms standardisation body, reflect the fact that the technology can be deployed in any of the 44 licensed bands worldwide, a consequence of a general trend towards ‘technology-neutral’ licensing. It is unlikely that an operator would require a handset vendor to support all 44 bands in a single device, but developing a smartphone capable of supporting the core LTE bands would effectively create a ‘world’ LTE smartphone.

With the recent introduction of its RF360 front-end solution, Qualcomm has potentially opened the door for a ‘world’ LTE smartphone that fully enables global LTE roaming. The chipset vendor explained recently that the new technology is capable of supporting 700 MHz to 2700 MHz LTE bands worldwide in a single device, and could generate economies of scale in “the same way that quad-band did for GSM and penta-band did for 3G”.

Qualcomm expects RF360 to be commercially available in the second half of 2013, initially targeting high-end devices. However, the large Asian handset manufacturer we talked to explained that it will take time for such technical improvements to reach the mass market, and smartphone vendors are therefore likely to continue selecting LTE bands according to immediate domestic and regional market demand – and, of course, cost of production – for some time to come.

Interestingly, Qualcomm has been addressing the ‘real estate’ challenge within smartphones’ printed circuit boards (PCB) whereby supporting more LTE bands demands more discrete radio frequency (RF) front-end components, which are placed between the antenna and the digital modem. The chipset vendor explained that with its RF360 solution, “instead of needing up to ten different designs to competitively support the required LTE band combinations around the world, an OEM may only need three, or even fewer, and the differences across those can be addressed without a change in board layout, or an increase in board space”.

This is a particularly relevant challenge considering the increasing demand for bigger screens, faster processors and connectivity, and better battery life, which means that today’s sleek smartphone designs leave little room to expand the PCB space required for further front-end components should manufacturers want their devices to support more LTE bands.

Thus we would expect Qualcomm’s RF360 solution to have a similar impact to its Snapdragon chipsets in the medium to long term. In October last year, US operator MetroPCS explained that the “availability of lower-cost 4G LTE smartphones is in part due to an increasing number of handsets utilising the Qualcomm 8960 (Snapdragon) chipset family. This standardisation is a major positive as it will enable decreasing unit costs over time and we believe lower subsidisation levels in the future”.

% frequency bands (MHz) used in global LTE deployments, as of July 2013
Source: GSMA Intelligence

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