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Page last updated at 02:07 GMT, Saturday, 10 December 2011

Can turning off analogue TV make broadband better?


Marc Cieslak looks at implications of white space technology on consumers

By Alex Hudson
BBC News

Insatiable demand for wireless services means that, despite new technology, the airwaves are running out of room. Could making use of the space between signals be the solution to all our problems?

By 2014, global data traffic will increase by 39 times from current levels, reaching 3.6 exabytes (around 3.9 billion gigabytes) per month, according to wireless firm Cisco.

And this means that current wireless networks are approaching breaking point.

Scale showing Whitespace between channels
Ofcom says: "The technology works by searching for unoccupied radio waves called 'white spaces' between TV channels to transmit and receive wireless signals."
"Signals at these frequencies travel further and more easily through walls."
"Compared with other forms of wireless technology like Bluetooth and wi-fi, white-space devices are being designed to use lower frequencies that have traditionally been reserved for TV."

Every device that uses wireless technology - from remote-locking car keys and TV controls right through to the latest smart phones or tablets - uses a part of the spectrum.

While it is hoped that 4G and LTE technology will relieve some pressure on capacity, many see this as only a short-term solution.

"People are becoming more used to being connected, having elements of their homes or workplaces linked up to something - everything from your laptop to your wireless network," says Richard Traherne, of product development firm Cambridge Consultants.

"The fact we're consuming more data means there is more pressure on this finite resource of radio spectrum."

The radio spectrum is where all wireless communication takes place and has traditionally been ring-fenced, with certain services using specific bandwidths.

TV channels are in one space, radio in another and telecommunications a third, all entirely independent from one another.

This means that within those groups, specific frequencies are not always being used.

"Years ago, when spectrum wasn't so scarce, it seemed like a good way of doing it," says Traherne.

"You won't get interference and those radio bands could be policed easily."

While safe and simple, the system does not use the full capacity of the spectrum and, with demand increasing exponentially, the now scarce frequencies to transmit data on have become a valuable commodity.

A report by Cambridge Consultants used the analogy of data traffic in the UK as a large road, which can still support normal traffic flow but during rush hour the traffic still grinds to a halt. In some other countries, the situation is even worse.

Happy coincidence

Much of the spectrum left unused for most of the time. The white spaces left free, as they are known, can be utilised by new technology designed to make use of every gap between broadcasts.

Rory Cellan-Jones
Spectrum refers to the airwaves over which all wireless communication - radio, television, mobile voice and data - takes place.

And more spaces in frequencies are about to open up as analogue TV is slowly phased out across the globe. More of a happy coincidence of timing than a direct cause and effect, the efficiency of digital TV has left more spectrum open and white spaces to utilise.

It is the range of these signals that excites developers of white space devices. Imagine how far TV signals travel, for example, and how they can permeate buildings in a way that current wi-fi cannot.

With broadband in rural areas and the so-called digital divide coming under increased scrutiny, this could provide a neat solution, with information able to travel over significantly greater areas.

The other big hopes are for it to provide enhanced wi-fi and innovations with machine to machine communication. This could mean automated meter readings for gas or electric services, taking scientific readings without leaving a base-station or even remotely fixing technical faults on a car - within reason of course.

What is different is that this service - unlike the 3G and 4G frequencies which were auctioned off to the highest bidder - will be opened up without licence, allowing a level playing ground between any interested parties.

Radio Antenna Being Built on Alexandra Palace
The first TV signals were broadcast in the UK in the 1930s

Once a device checks with an online database to see which frequencies are free in that location, it is clear for use by anyone.

In the US, this has caused no end of debate. Wireless association CTIA believes that licensing is "the best way to facilitate investment, innovation and competition" and to "generate auction revenue for the US Treasury".

CTIA CEO Steve Largent wrote: "Any band plan adopted by the commission for the repurposed broadcast bands must not sacrifice spectrum in the TV bands that is ideal for licensed mobile wireless broadband service to accommodate unlicensed use."

And there are problems. Most attempts thus far have been bogged down in bureaucracy.

"The road to US spectrum reform often feels like anything but a superhighway," writes Mary Brown, director of technology and spectrum policy at Cisco.

Most importantly, this is not really a new technology at all. The maximum speeds seen on optimum connections will not increase and Ofcom is worried that the technology to truly fulfil the technology's promise lags slightly behind its big ideas.

"It certainly is a challenge but we consider it a challenge that we can beat," says Rhys Hurd, of Ofcom.

Unless more is done to simplify the process of acquiring and implementing rural broadband projects, the digital divide will continue to grow and money pledged by the Coalition will remain all but worthless
Alice Barnard, Countryside Alliance

At the moment, proposals Ofcom believes will be implemented in 2013 rely on a database updated regularly to show which parts of the spectrum are in use at any given time.

This works using GPS signals telling the device exactly how far away from certain frequencies in use it is.

The hope is that in the future, devices will recognise which frequencies are free automatically, making the system as efficient as it can be.

"The European body are declaring that the specifications for this need to be very stringent to the extent that it's debatable whether they're realisable," says Traherne.

"They're taking a defensive position, technologists are being optimistic and it's a matter of time bringing those two together."

As the world slowly says goodbye to analogue TV, the white space spectrum could wave in a new host of innovations keeping the airwaves as busy as ever.

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