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Behind the Ofcom plan: four LTE networks, and not a lot else

Defining technology, without defining technology

The packaging of radio spectrum often makes a mockery of technical neutrality, and Ofcom's plan for the digital dividend is no exception though the regulator had surprisingly little choice in the matter.

Ofcom's proposal for selling off 250MHz of radio spectrum runs to 555 pages, with annexes and technical reports, but that's indicative of the complexity inherent in defining packages that will create interoperability while maintaining a façade of being technically neutral, not to mention fending off legal threats from existing operators who feel wronged by the whole process.

International interoperability is important to achieve economies of scale, and enable roaming between countries, but it's really hard to get that without dictating the technology to be used (as Europe did with GSM). Ofcom's proposal follows Europe's (mandated) lead in refusing to specify any technology, while packaging and auctioning the spectrum in such a way that makes Long Term Evolution (LTE) the only sensible option.

The regulator achieves that by selling off the lower band (790-862MHz) in 10MHz chunks, each of which is split into two 5MHz channels paired together but spaced 41MHz apart. That's perfect for the current incarnation of LTE (Frequency Division Duplex, FDD) which uses one frequency to send and another to receive, but poorly suited for competing technologies such as WiMAX. LTE can use bands wider than 5MHz, so Ofcom will ensure that bidders get contiguous chunks where possible.

Band map 800MHz

That gap in the middle won't get auctioned off at all, at least not yet.

The left-hand side of this band is still being used for some TV services (until October 2014 in Scotland) which impacts pairs one and two, while over on the right a few PMSE (wireless microphone) users are still clearing out from pairs five and six, and the emergency services are lurking just off to the right, so there's some work to do regarding mitigation. To make things fair, Ofcom is proposing that pairs three and four therefore have a coverage obligation: to provide a 90 per cent chance of 2Mb/sec indoors to 95 per cent of the country. It's up to the bidders to decide how all those issues impact the value of the spectrum.

Up at 2.6GHz, the regulator is slightly less dictatorial, but the majority of the spectrum is still bundled up in FDD-friendly pairs with only a single lot in the middle being sold off as an unspecified lump.

Band map 2600MHz

The pairs are 20MHz up here; 10MHz on either side of the 50MHz chunk in the middle. There's less encumbrance in these bands – Ofcom has been trying to get shot of them for half a decade, so there's a requirement for some care has to be taken in avoiding air-traffic control radar (which lurks just off to the right), but other than that it should be clear to use.

When T-Mobile and Orange merged into Everything Everywhere (EE) they promised to give up some frequencies at 1.8GHz, but aren't required to do that until September 2013. EE might chose to do that early, so Ofcom has plans to ensure such a relinquishment results in paired blocks of 5MHz to be sold off, but it's hard to see why EE would bother.

Ofcom's plan also explains how to sell off any 900MHz (2G) bands that operators hand over before the auction date, despite that being rather unlikely. Even the regulator doesn't bother doing the same for the 2.1GHz (3G) bands for which the operators paid so much 11 years ago.

Operators will be examining their options with reference to Ofcom's proposed cap on ownership by a single company, which is proposed at 210MHz of paired spectrum, and the annual licences to be levied on spectrum holdings acquired before the auctions (which we will be looking at later today), but at least they can rest easy knowing that the technology choices have been made, even if Ofcom won't admit it. ®

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