NTIA About to Start Deep Dive on 3450-3550 MHz Band for 5G

NTIA is starting a feasibility study for the 3450-3550 MHz band, though making the spectrum available for commercial use is no slam dunk, said Paige Atkins, outgoing (see 1807230049) associate administrator-spectrum, at the Commerce Spectrum Management Advisory Committee meeting Tuesday. NTIA is targeting the band as the next candidate for wireless broadband, Administrator David Redl announced in February (see 1802260047), noting DOD needs to find another location for military radar systems in the segment of frequencies that carriers may use for 5G.

“We’re ready to start,” Atkins said of a 3450-3550 MHz band study. “We’ve done some preliminary work.” DOD will look at potential access for commercial systems most likely via sharing, she said. The band's characteristics are “significantly different” from those of the adjacent 3.5 GHz citizens broadband radio service band, Atkins said. “There’s no predetermined outcome or quick fix,” she said. “We need to study the band and see what methods can be used for sharing.”

NTIA is taking a cautious approach, said CSMAC member Michael Calabrese of New America’s Wireless Future Program. “NTIA needs to be certain that federal incumbents can either be relocated to a different band or, worst case, compress their operations onto a much smaller portion of the band so that the remainder can be either reallocated or shared,” Calabrese told us. “The federal uses are not the same as in the CBRS band just above, where the Navy has determined it cannot relocate, but can be protected and share thanks to a combination of sensing and the new spectrum access system database.”

“Availability of mid-band spectrum will be critical for 5G deployments and future innovation and CTIA looks forward to working with NTIA, the DOD and other stakeholders on this new initiative,” said Scott Bergmann, senior vice president-regulatory affairs. “I’m skeptical about DOD’s willingness to move systems as long as sharing is an option,” said network architect Richard Bennett. “DOD approaches sharing in a primitive way. It would do better to invest in shareable technologies.”

Also on CBRS, Atkins said NTIA and its Institute for Telecommunication Sciences are working through software verification and a validation process ahead of certification testing for companies that will be spectrum access system managers in the band. ITS is preparing a precertification process for equipment used by the environmental sensing capability operators that also will serve in the band, she said. The official noted NTIA is pleased with the June spectrum policy summit it hosted (see 1806120056), with attendance exceeding expectations.

The FCC is engaging with NTIA on areas including the 3450-3550 MHz band, bidirectional sharing, a national strategy for unlicensed and the preparations for the World Radiocommunication Conference next year, said Julius Knapp, chief of the FCC Office of Engineering and Technology. “There’s a lot going on.” The regulator also is working with NTIA on launch of sharing in the CBRS band, he said: “There’s lots of pieces to it, including work that’s going on to be able to start to roll out initial commercial deployments, hopefully" this year.

Knapp urged CSMAC to coordinate with the FCC Technological Advisory Council. Both “have been doing work on 5G and there’s bound to be information that’s gathered on each side that would be valuable to the other so that we’re all pulling together in the same direction,” he said.

Redl plans to work closely with the group as it soon starts a new term with some new members. “I have focused on spectrum policy throughout my career,” he said. “I speak your language, as much as any lawyer does, and I plan to speak a great deal with you.” He said the administration is focused on exclusive-use spectrum, but sharing must be part of the equation.

The CBRS band, with its emphasis on dynamic protection areas (DPAs), will provide a model for future sharing, Redl said. “Replacing static exclusion zones with DPAs will maximize the commercial potential of a band while not losing the assurance that incumbent military radio systems will be protected,” he said. The administration wants “to kick the tires” on potential policies and regulations “that can help us maximize spectrum access over the long term,” he said.

CSMAC approved final reports from its subcommittees, including on spectrum efficiency, 5G and enforcement.

Making the federal government more spectrum efficient is tough, said committee member and consultant/professor Dennis Roberson. “The government is not like the commercial side. ... When we try to apply commercial principles into government regimes like this it’s just really, really difficult.” Roberson didn’t participate in the efficiency subcommittee because he thinks the task is impossible.

The report acknowledges the difficulty, but it’s possible to find a band where the principles could be tested, said subcommittee co-Chairman Bryan Tramont of Wilkinson Barker. “Maybe some bands would not be good candidates."

Redl told an International Symposium on Advanced Radio Technologies (ISART) conference, also Tuesday, that NTIA’s ITS is updating research dating to the 1970s on RF noise. “More devices means more noise,” Redl said. “The essence of a successful spectrum system is the ability to discern a specific signal amongst a sea of other signals, and every device that starts using spectrum resources adds to an increasing level of background noise.” Later this year, ITS will deploy a neighborhood-sized prototype system to monitor spectrum usage in collaboration with the University of Colorado-Boulder, he said. “A university campus is a great place to get a broad sample of different types of scenarios, ranging from quiet times between semesters, to the hectic days in the fall when students return to campus, and extreme crowd situations such as football Saturdays,” he said.

The federal government is focused on harmful interference, Redl said. The new focus is on interference prevention, detection and resolution (IPDR), he said. "It reflects an effort to capture the full scope of the challenge we face in detecting the sources of interference and then moving to resolve that.” In February, NTIA held a workshop for other agencies on IPDR, he said. Some 60 spectrum managers from more than a dozen agencies attended, he said. “Ideas that were discussed included the potential of a common database among agencies for interference-incident reporting, as well as researching how automation could be applied effectively in the future, to identify interfering devices in a congested environment."