White Space Radio Trial Checks Nuts And Bolts

The Cambridge test is not designed to convince Ofcom, but to check the practicality of white space radio, says Glenn Collinson

The trial of white space radio in Cambridge will look at whether the technology is commercially viable for a range of applications but, according to one of the key players,  it is not aimed at convincing the regulator Ofcom to allow its use.

White space radio uses spectrum that has been set aside for TV broadcast – but in any part of the country, systems will use “locally-empty”  spectrum, which is not in use at that particular location. In theory it should be able to ease the problem of providing broadband in remote areas, or else great coverage for a low-speed network, ideal for connecting meters or other telemetry equipment.

Some people have expressed doubts that white space radio can perform as claimed, and worry that it might cause interference to TV pictures by “bleeding” into adjacent frequencies. White space radio is not yet legal to use, and the Cambridge consortium has a special licence from the regulator Ofcom to test the technology.

So, is the project designed to convince Ofcom to allow it across the country, we asked one of the key members, Glenn Collinson, founder and director of white space specialist Neul. “No, Ofcom’s consultation process is now over,” he said – though he did say any data produced will be made available to the regulator. “We are very confident that Ofcom will make it licence-exempt.”

Ofcom has already outlined the proposals under which it could allow the use of white space radio, and Collinson hopes to hear soon when Ofcom will make the technology licence-exempt. Ofcom confirmed that it has all the input it needs and will be ruling on white space licensing soon. Building the database will take some time, but white space could be in legal use across the country by 2014.

Its likely “licence-exempt” status invites comparison with Wi-Fi, and in some reports white space radio has inherited the title “Wi-Fi on steroids” from WiMax. However, the technologies are widely different, with Wi-Fi operating at short distances and white space needing a geolocation database to operate legally under Ofcom’s proposals.

Specific test goals

The test will focus on specific issues. Firstly, it will be one of the biggest tests so far of whether the technology works as proposed. Secondly it will check on interference with existing radio users such as TV broadcasters, although Collinson is confident that won’t be an issue. “This is a very sophisticated trial over a large area,” he said, adding its results will increase the reliability of previous test results.

But mostly, it will be testing applications, which will include fixed broadband, mobile broadband and telemetry applications – gathering data from probes and monitors, such as the smart meters proposed by the UK government’s smart grid plans to promote energy efficiency.

The network will use base stations in the centre of Cambridge as well as in one of the villages near Cambridge to test the technology towards its limits of 10km – a part of the trial which sounds like a potential test for rural broadband.

The network will also be accessed by mobile terminals driving round Cambridge – a part of the trial which will interest participants Samsung and Nokia, although at present Neul’s mobile terminal  is the size of an A4 book, and not ready to be embedded in one of their phones.

The telemetry demonstration will be a link to a station measuring temperature and other weather data, said Collinson, though it could equally be applied to a smart meter.

“We are application-agnostic,” said Collinson. “We are not going after any specific application, and we wouldn’t want to pick up any bias at this stage.”

The test will run for at least three months, and then adjust its focus, he said:  “We expect this test network to be used increasingly over the course of this year.”

Neul’s role

Collinson was a bit cagey about the use of Neul hardware, as the test involves at least two other white space specialists. The test would definitely include six Neul base stations, he said, and would be testing their use ‘end to end’.  “It is still too early to test interoperability between different white space radio implementations,” said Collinson.

However, he did make the claim that Neul has “the only implementation of a white space radio system that is fully compliant with all the regulations,” implying that Neul is at least the lead hardware and possibly the only hardware in the project.