Of course, a roll-out in just one or two standard bands and in virgin spectrum is the simplest option, but it is not an option at all for the majority of cellcos. Even those with clean, unencumbered frequencies well sup-ported by LTE device makers, like Verizon's 700MHz roll-out, will soon run out of capacity and start to look for less pristine choices. So we are seeing a change in thinking, with Clearwire's long maligned 2.5GHz TDD spectrum appearing in a new light, and a UK operator even turning on LTE in the neglected 3.5GHz Wimax band.
Meanwhile, chipmakers are promising to make TDD/FDD support, as well as multiband devices, a matter of just a few dollars‘ extra cost, as TD-LTE enters the mainstream (and not just in China). The biggest source of already available mobile spectrum is, of course, the 2G bands, and the US is leading the way to refarming those at an unexpectedly rapid rate. All of which will create a patchwork of 4G spectrum with many technological compromises, but enough to end talk of famines and potentially dilute interest in new auctions.
In current LTE thinking, at least of the kind that drives the financial markets, there are many apparent inconsistencies when it comes to spectrum. On the one hand, we are faced with a “spectrum famine” as mobile broadband usage soars, but on the other, big swathes of already available frequencies above 2.2GHz go undervalued and underused.
And while the markets attach huge value to sub-1GHz bands, and penalize firms with none of that long range spectrum, much of what the next generation of networks will rely on will lend itself to the short range and high capacity of the higher bands – small cells and dense urban metrozones can often thrive above 2GHz, especially with femtocells or Wi-Fi to address problems of indoor penetration.
That thinking is changing as operators chase mobile broadband capacity and realize that auctions and M&A will often be the least effective way to achieve it. Instead, neglected bands are starting to come into their own, along with a heightened emphasis on rapid refarming of frequencies used for GSM, CDMA or Wimax.