Original URL: http://www.theregister.co.uk/2013/08/12/ofcom_seeks_input_on_future_of_wifi/

Should UK tear Wi-Fi a new one at 5GHz? Speak your brains, says Ofcom

This 2.4GHz town ain't big enough for both all of us

By Bill Ray

Posted in Policy, 12th August 2013 08:33 GMT

Ofcom, Blighty's fearless watchdog of the airwaves, wants to know if Wi-Fi needs more space.

The regulator is willing to allocate more radio spectrum to wireless networking - and wants Brits to be able to use those frequencies without the regulator having to auction them off to a corporate giant.

The consultation is, strictly speaking, about shared spectrum: how to give multiple users access to the same band and ensure they play nicely together. But behind it is a realisation that if we're going to communicate as much as we'd like then we need to fill the radio spectrum much more efficiently.

Fortunately that's Ofcom's job - to ensure efficient use of radio - and while auctions have hitherto been the mechanism of choice (on the basis that he who pays most will have most incentive to use the band) the success of Wi-Fi has demonstrated that the best way to fill a block of frequencies to capacity is to give it away for free.

Wi-Fi networking's success is a template, but one that needs refining. Its 2.4GHz band is overcrowded: the space is congested with wireless nets and various gadgets, and this interference affects speed and relaibility.

However, higher up the dial, the 5GHz band is relatively empty and there's another 300MHz or so which could be appended to that range. Using that block of frequencies is up for debate at the World Radio Conference in 2015, but Ofcom would like to know what the UK thinks. (There are disadvantages to using signals at 5GHz: they have a shorter range than 2.4GHz transmissions and they can't pass through walls and other solid things quite as well. But there's little or no congestion.)

The regulator is also looking for suggestions to improve utilisation. The 2.4GHz band, for example, is open to everyone and thus filled with all sorts of incompatible signals from baby listeners to car keys. Devices are limited in power, and duty cycle, but could share more efficiently if they all used the same protocol, were that mandated by a regulator.

It's too late for the existing bands obviously, but something worth considering when new frequencies are being opened up - and the Internet of Things starts demanding wireless capacity for machine-to-machine communications.

Putting hotspots outside

Ofcom is also concerned about Wi-Fi's aspirations on the great outdoors. Walls are pretty good at blocking the signals, so putting hotspots outside increases the interference disproportionately. With next-gen Wi-Fi networking, dubbed Hotspot 2, making such installations profitable (as mobile operators will pay the hotspot owner when their customers' phones roam seamless onto them, from the middle of next year) outdoor installations are expected to multiply fast.

These outdoor spots, and other point-to-point connections, can be hooked up to a fast backbone network using frequencies owned by a national licensee that can only be used within specific locations. The best example is US maritime radar: at 3.5GHz, it is obviously vacant when one gets inland, and will shortly be available through the White Space databases, which links empty bands to specific geographical areas.

Databases of that type are being set up to cover the UK now, with national trials scheduled for October. The UK databases, like those already operating in the US, will cover only empty TV bands - frequencies being used to broadcast TV elsewhere, but locally available - but the technique can (and will) be applied to other bands and Ofcom is looking for suggestions.

The last part of the consultation is perhaps the most interesting, to El Reg readers at least. It seems that Ofcom is thinking about setting up a database of experiments, allowing anyone to request a frequency or two in which to set up experimental transmissions. The idea is to spur innovation by permitting greater exploration, particularly in the bands currently falling under government ownership.

Much work of that kind is currently done in the amateur radio bands, by (generally) bearded obsessionals who spend their own money seeing what's possible. An Ofcom database would open up a load more bands, as well as letting companies experiment to push further, faster.

Ofcom would like your thoughts on that (PDF, very exciting if one finds unlicensed radio exciting, as one should), and the bands in which you think it might be fun to play as well as comments on the importance of White Space databases and the future of Wi-Fi, all by 9 November. ®