FCC and NTIA Collaborating on Spectrum, but Consensus Remains Challenging

The FCC and NTIA are working together as well as Ira Keltz has seen in his 30 years of government service, but the deputy chief of the FCC’s Office of Engineering and Technology said finding consensus on spectrum issues remains difficult. Keltz spoke Wednesday at the International Symposium on Advanced Radio Technologies (ISART) conference in Denver. Echoing Keltz was Derek Khlopin, NTIA deputy associate administrator in the Office of Spectrum Management.

“Consensus is defined as unanimity, as getting everybody to agree,” Keltz said. That’s “really hard,” he continued. “You can’t always get everything you want” and the progress that has been made has required compromise, Keltz added. If you ask five engineers how to approach signal clutter, “you probably get 12 different opinions.”

Regulators must put forward proposals that are “good enough” and “based in reality,” not necessarily the best or worst case, Keltz said. “We’re trying to look at things with a more realistic view,” he argued. There must be some "give and take" and ... "recognition of doing things realistically.”

The FCC has different goals with bands, Keltz said. In launching the citizens broadband radio service band, the agency wanted to “try out this new framework with this multi-tiered sharing system,” he said. In the 3.45 GHz band “we were trying to clear as much [spectrum] as we could” for exclusive-use licenses, he said. “There are other places where we kind of say, ‘We’re not sure exactly what will work, and we’re looking for ideas.’”

Reaching agreement on technical parameters for sharing a band doesn’t mean there's consensus on policy, said Khlopin, who is leading NTIA's work on the national spectrum strategy (NSS). “Different parties are going to come in with different technical analysis and the more you can push toward consensus … the better.”

The Interdepartment Radio Advisory Committee at NTIA has a record of success and has existed for a century, Khlopin noted. Successful examples of working together on spectrum don’t “make the news,” he said. NTIA coordinates “extensively” with the FCC and “the foundation is really good -- it’s strong,” he said. Moreover, the new Interagency Spectrum Advisory Council will help develop consensus (see 2402020034), he said.

Khlopin hears complaints that the NSS doesn’t require much from industry. “I promise you that’s going to change,” he said. “Expect forums [and] working groups,” Khlopin added. The strategy is designed “to figure out how to bring people together in a better way.”

One of the “emerging” challenges is handling passive services like weather sensing, Khlopin said. “Sharing among like systems is one thing.” It’s more difficult among different kinds of systems, he said.

Jeremy Glenn, policy analyst at NTIA’s Institute for Telecommunications Science (ITS), urged conference attendees to consider next steps. “Differences of opinion are great, and they spur further conversation,” he said: “This conference is the beginning of a process. … What do we do next?” Glenn asked how policymakers can move away from finding consensus in a way that makes every user of a band “equally unhappy.”

Trust is critical but often lacking in spectrum, ITS researcher Chris Anderson said during a panel discussion: “There have been multiple incidents where a system will come in and say, ‘We promise. We promise that you’ll be fine. We promise you won’t be interfered with.’” Incumbents have been “burned over and over and over again,” he said. “There’s an inherent mistrust.”

Anderson cited the example of the CBRS band. The Navy was initially inclined to be suspicious, he said. New users of a band must begin with “baby steps” that “demonstrate trust,” he said.

“We have to stop making worst-case assumptions every step of the way” as rules are developed for sharing spectrum, said Andrew Clegg, Google spectrum engineering lead. Instead, “we have to take a rational, statistical approach,” he said.

Clegg proposed a different way of addressing interference in the lower 3 GHz band, which is being looked at for 5G. Start with high power levels in limited areas and then dial them down until harmful interference goes away, he suggested. In CBRS, operations started with extremely low power levels to never cause interference, and we don’t know for sure what levels are possible, he said: “We don’t know how many dBs we’ve left on the table because interference doesn’t occur.”

Another CBRS issue is the lack of open-source clutter data, Clegg said. There's lots of good open-source terrain data but not clutter data, he argued.

AT&T spends a lot of time and resources on propagation models, said Neeti Tandon, a member of the technical staff at AT&T. “We do a data refresh all the time because new foliage, new buildings and new structures come up.”