Multi-Frequency Networks May Boost TV Spectrum Efficiency

Some broadcast industry officials we surveyed said they're interested in what CTB seeks to do, but they want more information before deciding whether they're interested. CTB representatives said they've recently begun speaking with full-power broadcasters about their technology. It uses equipment from Harris Corp. and will be tested at four low- power stations in Portland, Ore., starting in the coming weeks. Some who were involved with the Community Broadcasters Association, which represented low-power stations but is defunct, work with CTB.

Using multiple transmitters at 5 to 100 watts instead of a single one at thousands of watts would let a station use 3 Mbps of its 19.4 Mbps broadcast stream for video, said President Vernon Fotheringham. The other 16.4 Mbps could be used for other content, including video but also possibly Web material, he said. “Off-the-shelf” ATSC devices could receive popular content from a broadcaster using Internet Protocol, he said. That would “support the mass distribution of the Internet that is mass content” through a single port, he said. “So multiple devices can take down that information far more efficiently in terms of how it’s distributed and therein make a far more substantial contribution to solving the perceived spectrum crisis.”

The wireless industry for three decades has used networks like those proposed, which “have only now begun to become possible in the television world because of the digital transition,” Fotheringham said. “There are distinct advantages and benefits that the broadcast industry brings,” including a “multicast architecture” that cellular providers lack, he added. Fotheringham said CTB executives have spoken with representatives of the Association for Maximum Service Television, the Open Mobile Video Coalition and an unspecified broadcasting company. Executives we surveyed at companies that among them own about 130 TV stations -- 9 percent of U.S. commercial broadcasters -- wouldn’t comment or said they need to learn more about CTB. “CTB is really more of an IP Internet solution than a real broadcast solution,” or so it seems at first glance, said an executive.

MSTV is “looking at the technical aspects now and we'll probably have some follow-up meetings” with CTB executives, President David Donovan said. “It may or may not be a panacea. I think we need to look at it a little more.” There may be problems with having multiple transmitters in the TV band, and two-way communication “raises some interference issues,” he said. “When you have new technologies and proposals you really have to dig into them in significant detail.”

Instead of freeing radio waves for other purposes -- such as for wireless broadband as the FCC seeks -- CTB “uses what we have more efficiently,” said an attorney for the company, Peter Tannenwald of Fletcher Heald. FCC officials “are very interested in it,” he said, citing recent meetings (CD Jan 26 p8). “They understand the theory. They want to see it work.” Tannenwald added, “The answer we've gotten is, the longer it takes to get it up and running, the less likely it is that the spectrum will be there” because “there’s a political train running here.”