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Mandate "cognitive" techniques for unlicensed UWB, Ofcom tells CEPT

From "Ofcom recommends anti-interference wireless technology to EU" by Matthew Broersma, Techworld, 13 September:

"Ofcom has recommended that the European version of Ultra-wideband (UWB) should require additional anti-interference technology to prevent problems with wireless broadband systems. The communications watchdog issued its recommendation to the European Conference of Postal and Telecoms Administrators (CEPT) yesterday, following a lengthy consultation period. CEPT is in the process of harmonising UWB plans across the European Union in order to create a single unified market for the technology...

"'The US has already developed a specification for UWB. However, Ofcom believes that this does not provide adequate protection against interference with other wireless devices in Europe because of the different uses of radio spectrum in the US and Europe,' Ofcom said in a statement. The solution is for UWB systems in the 3.1 to 4.2GHz bands to be fitted with 'detect and avoid' systems, which search for nearby broadband wireless signals and switch frequency to prevent interference, Ofcom said. Devices can do without such anti-interference systems only if they are transmitting below a power level of -85dBm/MHz, Ofcom said...

"Among Ofcom's other anti-interference recommendations were for UWB transmitters to use Transmit Power Control technology for situations when a number of other UWB devices are nearby, and for the introduction of a minimum Pulse Repetition Frequency...

"Ofcom's full recommendation to CEPT is available from Ofcom's website [pdf]."

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For background see Techworld's earlier article, "Ofcom to blaze UWB trail in Europe" by Peter Judge, 11 November 2004.

Additional points from Ofcom's UWB recommendation:

"Studies have shown that if the UWB device use is limited to indoors only, then the interference potential to other services is reduced significantly. However, it is hard to see how this could be enforced in practice. The UK recommends that the use of UWB on board ships, aircraft and for fixed out-of-doors systems should be prohibited. UWB transmissions levels lower than -85dBm/MHz have been recommended below 1.6GHz..."

Note that Japan released its draft rules for UWB a few weeks ago. They propose to require a "detect and avoid" system for the 3.4 to 4.8GHz frequency range, but otherwise accept the mask approved by the US Federal Communications Commission for the 3.4 to 4.75GHz and 7.25 to 10.25GHz ranges. The discrepancies between the American, Japanese and European rules for UWB will not help manufacturers.

We must also note that Ofcom has just recommended that CEPT should mandate unlicensed cognitive access to licensed bands. Yet during their "Spectrum Framework Review" last winter, Ofcom asked the public whether they should do that in the UK. Their preliminary answer was that they would not. We criticized that position at great length in our comments for the Spectrum Review consultation, but they said "no" again in their final statement ending the consultation. Have they finally "seen the light"?

[UWB: 13 September 2005]