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OFCOM Says LTE Will Interfere With TV Channels

A recent consultation from U.K. regulator OFCOM raises concerns that adjacent channel LTE wireless broadband will cause interference to adjacent channel broadcast TV reception.

The Executive Summary states, "We have undertaken an extensive research exercise that has indicated that the potential impact of interference on DTT consumers is of such a level that we must take mitigating actions. Therefore, after careful consideration of the problem in the context of our duties under the Communications Act 2003 and European legislation, we are setting out a framework of proposals within this consultation document that we consider best balance the competing interests of those involved in using the 800 MHz spectrum and DTT."

Broadcasters in the United States operating on Channel 51 are likely to experience similar problems when wireless broadband operations begin on Channel 52 (and possibly on other channels, depending on the FCC's plans for taking an additional 120 MHz from the broadcast TV bands).

"Our proposals center around establishing an implementation body to manage the delivery of some of these mitigating measures," OFCOM said. "This will be a single body that will act both to aggregate and provide information to and from consumers, broadcasters, and new 800 MHz licensees, as well as co-ordinate the use of mitigation options to reduce the potential interference."

Mitigation measures include filters for digital terrestrial television consumer equipment, filters for mobile base stations, changes to antennas that include reorientation and cross polarization, platform changes, and mobile base station power reductions. OFCOM proposed that the cost of creating the implementation body and the work that it carries out should be borne predominantly by the new licensees of the 800 MHz spectrum.

It is important to note that this is a consultation (similar to the FCC's Notice of Inquiry or Notice of Proposed Rule Making) and not a final ruling. Comments may be filed until the consultation closes on Aug. 11, 2011.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.