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September 23, 2011 3:18 pm
Plans for super-fast wireless services delivered via the unused parts of the airwaves previously reserved for television broadcasts are being devised. This is intended to fill the need for scarce spectrum, as mobile users become increasingly hungry for data on the move.
The amount of spectrum available for mobile use is limited, and owned by only a few major companies in many global markets. This means there is an escalating problem in trying to satisfy the demands of consumers who have come to expect fast downloading of applications and video without overloading the network.
Companies are looking to improve the efficiency of how they use their existing spectrum, or else trying to find spectrum so far not used. One such option is so-called “white space” that will allow mobile users to tap into spaces in the radio spectrum previously reserved for TV broadcasts.
These gaps are meant to minimise interference from adjacent channels, but national regulations in Europe and the US are drawing up plans to use this valuable – and normally not owned – spectrum at no cost as long as systems can be created to prevent intrusion.
Although technical in nature, the effect will be remarkably simple for users. They should not even notice its existence, other than finding a very fast and much more extensive wi-fi service that potentially enables networks to stretch across towns and cities.
In fact, given the quality of the TV spectrum, the white-space signal can carry several miles and can penetrate far more easily through walls. Ofcom, the UK regulator, has estimated the amount of white-space bandwidth to be comparable to what is available for 3G services, and more in some locations.
The new technology is expected to aid the development of new applications for both personal as well as business use, with experts predicting the establishment of a range of so-called “machine-to-machine” communications for automated devices that need to interact. This could be used, for example, to wirelessly measure utility meters in homes, or keep an inventory of stock for a business.
Ofcom estimates that about a fifth of UK households use wi-fi, but the biggest use is among businesses: as many as three-quarters have local networks. However, this spectrum has relatively poor quality, which equates to a very limited range within buildings.
Importantly, it could help remote rural areas that do not have the necessary cabling to connect to high-speed broadband services. One test of the new technology is being carried out on the Isle of Bute, Scotland, by BT, the telecommunications group. The company is primarily interested in using white space to meet its commitment to provide high-speed broadband coverage to the UK.
White space could be useful in connecting the last 2 per cent of the country that is unreachable by the superior fibre-cabling used for fast broadband. White space can be used to link homes to the telephone exchange in remote areas, as the spectrum is good enough to carry over hills and sea, and for distances of up to 10km.
Sean Williams, group director of strategy, policy and portfolio at BT, says: “There is a huge demand for data, but limited spectrum, and using the white space represents part of the answer. There is a lot of unused, but high-quality spectrum. Wireless broadband is an important part of how we can cover the UK.”
The UK is also likely to be among the first to adopt wider white-space coverage. Ofcom is leading the European agenda on white space, having unveiled plans in September to provide the regulatory backbone of a functioning network. The regulator will create a central database to help devices find the right space in which to operate without causing interference, and is also considering the future use of other white spaces, such as those in the band used by FM radio services.
“This is about finding the opportunities to maximise the use of the spectrum. This is an opportunity for Britain to lead the way in Europe at the forefront of research and investment,” says Ed Richards, chief executive of Ofcom.
Another UK trial involves a consortium that includes BT, Microsoft, the technology company, Google, the internet search business, and BSkyB, the satellite broadcaster, exploring the potential of white-space technology in a range of applications in Cambridge. Richard Walker, head of wireless at TTP, a technology development company that is also part of the consortium, estimates that more than 600,000 premises in the UK are poorly serviced by conventional broadband. They could be connected using cheap hardware operating in unlicensed TV white space, rather than expensive optical-fibre connections.
TTP has established a 6km white-space broadband link between its offices near Cambridge and premises in the nearby village of Orwell, and is on track to deliver 6 megabits per second using a single TV channel. “Assuming Ofcom gets the key legislation in place … we could expect deployment of an innovative array of white-space systems and applications during 2013,” Mr Walker says.
Similar trials have been conducted by Microsoft in the US, where white-space technology is also likely to be embraced.
While the participants of such tests have lofty ambitions for this innovation, the proof will be in the adoption by telecommunications companies. Device manufacturers such as Nokia and Samsung will also need to be encouraged to equip smart phones with the ability to run on these airwaves.
The technology is not overly complicated, however. This means that if the national regulators feel sure that it will not cause interference with other broadcasts – and so far there has been no evidence that it will – then consumers should be able to benefit from the ability to tap into a new and better version of wireless mobile services in the years to come.
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