02.05.09

Other White Space News

Posted in Europe, hidden node margins, white space at 5:04 pm by JamesNeel

Beyond the launching of the database group news below.

(link) White spaces may be coming to Europe.

But the UK is not the only market in Europe, and in less space-restrictive countries it could be practical to utilise white spaces, which explains the White Space Coalition launching a European campaign at the European Conference of Postal and Telecommunications Administrations.

Dr. Alexandre Kholod, of the Swiss Federal Office of Communications, told PolicyTracker, after the meeting, that he didn’t see much spectrum available once mobile and PMSE* applications had been served. The French spectrum agency, ANFR, is preparing a report on the subject of white space use in France, but there are significant concerns about the ability of cognitive radios to avoid TV transmissions.

(link) Canada too. Though their transition isn’t until 2011 so they have some time. Since it’s hard to find a good excerpt, here’s my quick summary. The Canadian Radio-television and Telecommunications Commission (CRTC) is holding hearings starting Feb 17 where white spaces are expected to come up. The CRTC regulators have apparently been following along with and interacting with the FCC efforts.

(pdf) Ofcom released ERA Technology Limited’s analysis of hidden node margins for cognitive radio devices in TV bands (B.S Randhawa, Z. Wang, I. Parker, “Anaylsis of hidden node margins for cognitive radio devices potentially using DTT and PMSE spectrum”). Excerpts from the summary and conclusions:

In the Digital Divident Review (DDR) statement Ofcom indicated that cognitive radio devices (CRD)s will be allowed to use the interleaved spectrum subject to being satisfied that they will not cause harmful interference to digital terrestiral television (TT) or programme making and special events (PMSE) applications. A cognitive device will therefore be required to monitor the UHF band for DTT and PMSE transmissions before being allowed to transmit on locally unused channels.

A short project was previously undertaken by ERA to determine indicative values of the hidden-node margin through direct measurements. This trial estiamted that the average hidden node margin for a cognitive radio device to sucessfully detect a DTT signal at 1.5 m for approximately 90% of all locations, was about 25 dB but in some situations a marfin of 30 dB or greater could be required.

The hidden node calcualtion was bound to an ara defined by the unwanted cognitive interference being greater or equal to the received wanted signal minus the co-channel protection ratio of 25 dB and an extra fade margin of 25 dB, based on the assumption that if the level of inerference was less than a sensitivity level of -117 dBm the cognitive rdevice would not cause interference to the PMSE receiver.