A few years ago it was widely assumed that the 900-MHz and 1.8-GHz GSM bands, widely used in Europe and other regions, would automatically be used for HSPA expansion when the time came to refarm the spectrum.
In the past couple of years, the sentiment surrounding 1.8-GHz has changed significantly, with many operators planning to use it to add LTE rather than HSPA capacity. This reflects a general acceleration of wide scale LTE rollout plans even in regions, like Europe, where there will still be heavy reliance on HSPA+ expansion for the next five years or more.
The change of heart on 1.8-GHz has reached such a level that groups such as the GSM Association now regard the spectrum as one of the most attractive for global LTE roaming, especially as the US FCC has started discussion of possibly opening up its own frequencies in this area for mobile services.
Until recently, however, the 900-MHz band was still earmarked, in the minds of most, for GSM/EDGE coverage and then migration to HSPA+. Now the same shift of thinking which was seen in the higher band is also affecting 900-MHz, with a rising number of operators considering refarming this spectrum for LTE rather than HSPA when the time comes. This shift in assumptions is not as dramatic yet as in 1.8-GHz, but may become so. It is driven by three main factors:
- A general desire to secure as much spectrum as possible for LTE capacity and coverage. This is seen as mobile data levels rise, and operators believe that LTE will handle these better than HSPA+, especially when LTE-Advanced addresses some of the limitations of low frequency, low capacity spectrum. In Europe in particular, LTE was seen until 2010 mainly as a hot zone technology, with cellcos expecting to rely on HSPA+ for wide area data coverage for several years. However, they are now seeing the need for true mobile broadband even in suburban areas, and so are considering a far quicker progress towards near-national LTE coverage.
- That, in turn, has put more pressure on sub-1GHz bands, which better support less densely populated areas, broad coverage and indoor penetration. This has put a new spotlight on 900-MHz, especially for carriers which have failed to secure licenses in the 800-MHz spectrum auctions, like E-Plus in Germany.
- With some operators leading the way with deployments and trials, there is greater confidence that device vendors will support the 900-MHz LTE band.
Fans of LTE900 argue that it scales better than LTE and has a forward path to LTE-Advanced, and therefore to being combined with LTE in other bands.
While many European carriers are now weighing the pros and cons of HSPA+ versus LTE for future refarming in their 900-MHz spectrum, use of the band for 4G is currently mainly driven by the Middle East region. Option recently introduced one of the first LTE devices, the Beemo dongle, to support the three main European LTE bands (800-MHz, 1.8-GHz and 2.6-GHz) plus 900-MHz for roaming in the Middle East and, in future, other countries.
In Europe, these will include Sweden, and there is a particularly interesting situation in the UK, where the three main cellcos unusually do not have the same GSM bands. Vodafone and O2 gained 900-MHz spectrum for 2G, while Orange and T-Mobile (now merged as EverythingEverywhere) had 1.8-GHz. This has led to many disputes over the rules for the upcoming auction of 800-MHz and 2.6-GHz spectrum, scheduled for late this year.
EverythingEverywhere has been arguing that its two rivals should be capped in how much new sub-GHz spectrum they should be allowed to buy, since they already have 900-MHz holdings (low frequencies are most coveted for phase one roll-out because they can cover wide areas cost effectively and sup-port good indoor penetration).
But Vodafone and O2 retort that 900-MHz will be a less attractive LTE band than 800-MHz because its device ecosystem is evolving more slowly (and uncertainly), and that EverythingEverywhere has the advantage because it holds 1.8-GHz frequencies, increasingly regarded as the ideal band for LTE because of its global support and because it offers a balance between the coverage of the low frequency bands and the capacity of the higher ones. The fourth UK mobile player, 3UK, only has 3G spectrum in 2.1-GHz.
The outcome of the UK auction will be an important one in deciding how much momentum builds behind 900LTE, especially if a major operator is left without 800-MHz licenses and is therefore obliged to drive forward 900-MHz usage and devices – something a huge player like Vodafone or O2 parent Telefonica is very capable of doing.