Page last updated at 15:18 GMT, Monday, 11 May 2009 16:18 UK

Can't connect, won't connect.

Baby monitor and DAB radio
Baby monitors use frequencies that do not require a licence.

Poor wireless reception is symptomatic of a much bigger issue, says regular columnist Bill Thompson

The BBC's technology correspondent, Rory Cellan-Jones, must be hoping that his neighbours don't decide to have a larger family.

He recently spent ages setting up a high-speed wireless network (wi-fi) at home, documenting the whole tortuous process on the BBC Technology blog, but all his hard work could apparently be ruined by a single baby listener.

The intercoms that let parents listen in to every snuffle, sob and cry operate in the same frequency band as wireless networks and can generate so much interference that they make the wi-fi unusable.

The television re-broadcasters that many people use to watch satellite TV in the bedroom (without having to install a second set-top box) also use the same frequency, because it is one of the few areas of the radio spectrum that does not require a licence; they too can slow down wi-fi speeds or make it hard for a computer to make a connection with a local network.

These unwelcome findings about interference come from a detailed survey by Mass Consultants, carried out on behalf of the telecoms regulator Ofcom, as part of its investigation into how radio spectrum is currently used and should be allocated in future.
Bill Thompson
I can see 18 networks apart from the one I'm connected to, so I can vouch for the scale of the problem
Bill Thompson

They found that in central London, the number of overlapping networks attempting to use the same channel was a significant problem, and that in some areas nine-tenths of the available bandwidth was being used by wi-fi nodes advertising themselves or doing general housekeeping, with only one-tenth actually available for user data.

Outside major metropolitan areas the real problem was interference from other devices using the same frequency ranges.

As I write this in a café near Holborn I can see 18 networks apart from the one I'm connected to, so I can vouch for the scale of the problem in London!

Wi-fi is far from robust in normal circumstances, as anyone who has wandered around a house with a laptop looking for a spot that gets a decent signal will testify.

Back in 2006, consultants AirMagnet got some useful pre-Christmas publicity when it announced that reflections from tree baubles and tinsel could cut wireless signal strength by a quarter in a well-decorated home.

But these findings reveal both the growing popularity and importance of wireless networks for home and business net use, and the urgent need to do something about it. Imagine how nice it would be if most wireless networks were suddenly five or even 10 times faster and generally reliable.

There is, of course, a simple if somewhat radical solution to the problem of having to squeeze wi-fi, baby alarms and TV re-transmitters into the same frequency range as remote controls, children's toys and many other devices. We could get rid of them, or at least, the ones that cause trouble.

The problems arise because the devices are analogue and use a wider band of frequencies than their digital counterparts. On top of that, the signals are far more variable than digital signals expected by a wi-fi receiver, so if we made them all digital, we could design them so as to not to interfere.

Of course this won't happen, because owners won't accept that the analogue devices they've already paid for and used for years have to be sacrificed in the name of a bright shiny digital future.

I can see their point, even if part of me just wants to sweep their old technologies away in favour of an uncluttered wireless world.
Royle Family
People are unlikely to throw away their old remotes to allow for better wi-fi

Another solution would be to move wi-fi away from the currently unregulated 2.4 gigahertz frequency band it uses, but here we face much bigger issues than the objections of parents and sports fans.

Vast tranches of the radio spectrum, from 9 kHz to 275 GHz, is taken up by radio and television, both the older analogue transmissions that are currently being switched off and the newer digital services that replace them: DAB and digital terrestrial television.
If we got rid of the analogue and the digital services and replaced the whole thing with a high-bandwidth wireless network service then we would have more than enough room for laptops and baby listeners.

Yet even if Ofcom decided this was a good idea - and it won't - there is an international dimension to the issue as the International Telecommunication Union's Radiocommunication Sector has the task of ensuring that the many systems in use do not interfere with each other.

Much of the ITU's work is about balancing competing desires, but there are also real physical limits on what can be done. Some frequencies, for example, are used by remote sensing devices in satellites because they are characteristic of water or growing plants, and obviously these can't be changed by administrative fiat.
But as with so many established practices and procedures, from copyright law to the regulation of the financial markets, digital technologies both create new opportunities and challenge or undermine current practice.

The ability to make perfect digital copies has led to the crisis in the music and film industries, and the availability of digital communications channels is causing us to question the wasteful use of spectrum by analogue devices.

Unfortunately, it seems unlikely that we'll see a wholesale rethink of the way spectrum is allocated, and the lack of political will means there is little chance that those pushing for deregulation of broad swathes of the spectrum will have any success. We will have to live with dodgy wi-fi for a while yet.

Bill Thompson is an independent journalist and regular commentator on the BBC World Service programme Digital Planet.

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