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:
ñ 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 hotzone 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 licences 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.