Original URL: http://www.theregister.co.uk/2011/04/08/ofcom_600mhz/

What will we do with 600MHz?

Local TV for local people ...

By Bill Ray

Posted in Broadband, 8th April 2011 10:24 GMT

4G licences are getting all the attention these days, but the switch to digital released another big chunk of radio spectrum which no one seems to know what to do with.

The 4G licences currently being discussed by Ofcom stretch across 790-862MHz (known as 800MHz), and 2.50-2.69GHz (the 2.6GHz band), but switching off analogue TV has also released a chunk from 550MHz to 606MHz, between the two digital TV bands and with wireless microphones perched on top (at Channel 38, 606-614MHz). But, despite having even better propagation than the hotly anticipated 800MHz band, 600MHz is the unloved sibling that most seem to think will end up carrying local TV, or simply be left to lie fallow while network operators pack 800MHz fit to burst.

The problem is standardisation. While 800MHz (and 2.6GHz) are both being standardised for 4G across Europe and by extension the world, 600MHz is just a UK thing.

Most countries are planning to continue broadcasting TV on that band, digital or otherwise, and while we could do that too, there's not a lot of appetite for more broadcast TV in a country full of iPlayer viewers and YouView boxes.

That was the conclusion reached in last year's consultation on the subject (64-page PDF/859 KB): most respondents seem to think that broadcast TV is the most likely thing to fill the space. It seems that only Channel 4 could muster any interest in reserving the spectrum for some more High Definition channels – the 600MHz band could fit one national multiplex, carrying six HD channels – and Channel Five was equally adamant that there's no demand for additional free-to-air broadcast capacity.

With no national broadcasters interested, the government has high hopes for community TV stations, operating along the lines of Community Radio – local television for local people, run on a not-for-profit basis for the good of the community. Given the number of Reg readers already involved in pirate, and community, radio you will probably be the ones asked to run local TV stations too. It's very questionable whether there's enough quality content to make such a project viable, and the government has told Ofcom it doesn't want 600MHz reserved for broadcast TV, so what else could we use it for?

Mobile telephony would seem the obvious application – we're always being told there isn't enough bandwidth to go around – but without international agreements, it's hard to make use of new bands. LTE (4G) will happily run down at 600MHz, and GSM is still to be found around 450MHz in some parts of the world, but adding another frequency band means adding another place where a mobile handset will have to search for a signal when it's switched on.

Already a phone must scan through 12 frequency slots at 2.1GHz to check for a 3G signal, checking each received signal against a list of roaming partners stored on the SIM. Handsets supporting UMTS900 will want to check five slots at 900MHz too (and if the user is on O2, and in London, then it might just find one), but if that fails then the handset will have to check three or four GSM bands (there are 14 such bands, but most handsets only support around four), and each of those has its own slots too. That's before we start to talk about UMTS1800, and LTE popping up at 800MHz, 2.6GHz and just about everywhere else.

Handsets aren't quite that stupid; by default they assume they can attach to the same network they were last connected to, and failing that they'll check frequencies owned by the same operator (depending on the intelligence of the handset). However, the point is that scanning all those bands is complicated, and scanning a band where there's no international agreement on slots or technologies is next to impossible.

This means that any application for 600MHz isn't going to be mobile telephony, despite Everything Everywhere's optimistic suggestion that Ofcom sits on the frequency until some future date when it becomes harmonised.

We could use it for point-to-point connections, lightly licensed as 5.8GHz is currently. That would enable rural communities to link into internet connections over tens of miles with cheap kit, connecting up hundreds of not-spots without government-subsidised satellites or giving more money to BT. But that wouldn't fill the airwaves to capacity across the UK – which is Ofcom's primary remit (specifically "ensuring efficient use of radio spectrum", not "serving the interests of the biggest companies" despite how often the two things seem to overlap).

Ofcom had said that the consultation on 600MHz would be out by the end of March this year, though given the amount of effort the regulator had to put into the 4G proposals that's likely to have slipped more than a bit. When discussing the 4G auctions, the leader of Ofcom's Spectrum Policy group, Hyacinth "H" Nwana, suggested that the broadcast TV channels could end up being sold off as "there are players waiting" to buy them and broadcast TV has had its day.

But with such little interest or application for 600MHz it's hard to imagine who would be interested in buying the frequencies surrounding it, unless Ofcom knows something we don't. ®