Carriers Already Sharing Spectrum Every Day, PCAST Report Proponents Say
The President’s Council of Advisors on Science and Technology’s controversial report on spectrum sharing proposes a national process for sharing, but sharing itself is not new, said Preston Marshall, who worked on the report, during an Information Technology and Innovation Foundation panel Friday. “There’s really nothing in this report that we don’t do today,” he said. The report, released in July (CD July 23 p1), has raised concerns both with carriers and on Capitol Hill (CD Sept 14 p1). In a key conclusion, PCAST recommended that the administration direct agencies to identify 1,000 MHz of spectrum that could be shared with the private sector.
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PCAST didn’t say there should be no more exclusive-use spectrum, said Marshall, professor of engineering at the University of Southern California and a former Defense Advanced Research Projects Agency official. “The PCAST report recognizes or believes that clearing is becoming increasingly difficult, costly and disruptive,” Marshall said. “We need to find a new metaphor for managing spectrum. This isn’t to say we walk away from individual band clearing where it’s possible. But where it’s not possible we don’t just leave that spectrum fallow."
The PCAST report also isn’t a “blue sky” report, Marshall said. “It is far from that, believe me,” he said. “Our believers in blue sky are equally mad at the PCAST report because their pet technologies aren’t in it, at least in the initial baseline.” Marshall noted that carriers are already sharing spectrum on a daily basis. “What’s new in PCAST is it says this shouldn’t be one-on-one processes between an individual commercial user and a federal agency via NTIA, but it should be broadly based,” he said. “It should be public. It should be transparent. We should go through the entire inventory of federal systems and find all the sharable spectrum.” One oft-heard criticism is “carriers won’t invest in shared spectrum,” but that is countered by recurring announcements carriers are investing in Wi-Fi to supplement their networks, Marshall said. “There is no spectrum lousier than Wi-Fi,” he said. “It’s congested. It’s crowded. It’s massively shared."
"What PCAST was really addressing was what I call the great disconnect in telecom policy and that is scarcity amidst abundance,” said Michael Calabrese, director of the New America Foundation’s Wireless Future Project, who also worked on the report. “Actual spectrum measurement studies” show “that less than 20 percent of the beachfront spectrum is actually in use, even in the most congested cities,” he said. Exclusive-use spectrum, “spectrum that sets the business model of carriers today,” is scarce, but most spectrum is underutilized, he said.
"Licenses are for exclusive use, not non-use, and that goes I think doubly for federal spectrum,” Calabrese said. “With PCAST, the basic thrust was to identify and open the most underutilized and useful bands for opportunistic sharing on a secondary basis, but subject to band-by-band conditions protecting incumbent users.” Calabrese said the record is clear: “Clearing and reallocation for exclusive commercial use is simply not sustainable, or at least not fast enough.” Calabrese noted that 1,700 MHz below 3.7 GHz is dedicated to radar, radio navigation or radio telemetry and sees little use. “It’s unlikely that most of that will be cleared for auction, yet there is tremendous capacity for that to be shared,” he said.
Qualcomm Vice President Dean Brenner said like many Washington debates, the debate over spectrum is polarizing. “Actually, as I heard Preston’s oral presentation, and some of Michael’s oral points, there’s a lot more agreement than disagreement,” Brenner said. “I don’t think that sharing is the sole means that should be pursued, but Preston didn’t say that today.”
The “big challenge” is that wireless data use in the U.S. is likely to double every year for the next 10 years, Brenner said. The government shouldn’t abandon the hunt for more exclusive-use spectrum, he said. “No one says, ‘Let’s just give up on that.’ But on the other extreme, we need more unlicensed spectrum as well.” On the unlicensed side, the U.S. needs wide chunks of spectrum, he said. “802.11ac, which really is ’super Wi-Fi,’ it’s here today, can use up to 160 megahertz-wide channels.” Spectrum sharing has a role to play, Brenner said. “There is spectrum that could be made available, not [on] a 24/7 basis, not on a coast-to-coast basis, but subject to protecting the rights of the incumbents,” he said. “That is great. We shouldn’t just throw up our hands if a particular band can’t be made available 24/7 coast-to-coast."
Questions remain about whether carriers will invest in shared spectrum, said Peter Rysavy, president of Rysavy Research. “Is an operator going to invest billions of dollars in infrastructure for a network … they may have for six hours at a time?” he said. “I agree it’s completely predictable for that interval of time. From a capacity management point of view, can you manage a network where you don’t know on any day what your capacity is going to be?”