NTIA: 3.45-3.55 GHz ‘good candidate’ for mid-band sharing

It’s no secret that the U.S. wireless industry is hungry for mid-band spectrum for 5G, and a new National Telecommunications and Information Administration (NTIA) report determined 100 MHz in the 3.1-3.55 GHz band looks most viable for near-term sharing with commercial wireless services.  

Specifically, the NTIA concluded the 3.45-3.55 GHz portion is “a good candidate for potential spectrum sharing, including the commercial power levels sought by the wireless industry.” The report follows a technical analysis released in January that found “a clear possibility” for real-time spectrum sharing to protect federal operations in the band. Federal users such as the Department of Defense (DoD) already occupy those frequencies, including shipborne, airborne, and land-based operations, mainly using radar systems.

NTIA’s second main finding in its report (PDF) to Congress determined some sharing could be possible below 3.45 GHz. But it noted that both classified and unclassified federal operations already using the frequencies “could be problematic for sharing with a commercial wireless system.” This could be exacerbated if federal users are shifted down from 3.45-3.55 GHz to make room for commercial services, according to the report.

RELATED: NTIA cites progress in 3450-3550 MHz band for sharing

Ultimately, the report says more study is needed to look at different sharing mechanisms and potentially relocating some federal users to lower portions of the band. NTIA’s report didn’t differentiate between licensed and unlicensed users.

Still, at least one commissioner at the Federal Communications Commission (FCC) didn’t think the new report went far enough.

FCC Commissioner Michael O’Rielly said on Twitter that NTIA’s report was “weak” and “harms US 5G readiness.”



Last December, the Federal Communications Commission (FCC) proposed clearing non-federal users from the 3.3-3.55 GHz portion, and to prepare the band to potentially give commercial users access to 250 megahertz of mid-band spectrum.

5G Americas President Chris Pearson in a statement said the organization was happy with NTIA’s recommendation, but indicated more spectrum is still needed.

“We are pleased that NTIA has recommended commercial access in the upper 100 MHz of the 3.1-3.55 GHZ band. Yet over 70 countries from around the world have agreed to target spectrum for 5G at 3.3 GHz and up, often with 200, 300 or more MHz of spectrum, since 3 GHz is a sweet spot for both coverage and capacity,” Pearson stated. “It is important for the federal agencies to free up more mid-band spectrum for the mobile industry to reach the full potential of 5G. Now that NTIA has issued its report on the full 3.1 - 3.55 GHz band, it is critical that the federal agencies work closely with industry at successful solutions to free up more spectrum in the band.”

RELATED: 5G Americas: U.S. needs mid-band spectrum, stat

CTIA SVP and General Counsel Tom Powell also urged the government to keep pace with other countries on mid-band spectrum for the wireless industry.

“The Administration needs to move quickly to free up as much spectrum as possible in the Lower 3 GHz band, so that we can match steps that so many other countries have already taken to commercialize midband spectrum,” Powell said in a statement on the report.

While the U.S. has freed up significant amounts of high-band millimeter wave spectrum for 5G, it's been slower on mid-band frequencies that many countries are using to roll out next-gen mobile services.

RELATED: Verizon, T-Mobile both rank best and worst among global 5G operators

CTIA has previously targeted the 3.1-3.55 GHz band as one of two clear opportunities for mid-band 5G. In March, the industry group said that even with the upcoming C-band and CBRS auctions, the U.S. would need to effectively double its licensed mid-band spectrum availability to match other countries, citing a study by Analysys Mason.

In the U.S., T-Mobile is the only operator deploying 5G with mid-band, thanks to the 2.5 GHz holdings it acquired through its Sprint merger. Even though T-Mobile is moving quickly to turn on 2.5 GHz, integration is still a process and the mid-band spectrum is activated in a handful of markets so far.

The first chance for licensed mid-band spectrum comes atter this month when the FCC auctions 70 MHz of priority access licenses (PALs) in the shared 3.5 GHz Citizens Broadband Radio Service (CBRS) band.  There is already 80 MHz available for unlicensed General Authorized Access (GAA), operating under a unique sharing paradigm that protects federal users.

RELATED: Verizon’s CBRS 3.5 GHz deployments on the rise – RootMetrics

The C-Band auction slated for December will offer 280 MHz of licensed spectrum, though it will take time for that to be put to use.

In terms of moving forward, NTIA recommended four aspects to focus on for the entire 3.1-3.55 GHz band: more in-depth assessment of the extent each federal system is used; developing a reliable mechanism to coordinate commercial users when federal systems are operating; assessing possibility of relocating federal systems like nationwide airborne systems; and fourth, that the FCC seriously consider setting tighter limits on out-of-band emissions for commercial operations.

RELATED: DoD doubles down on 5G testbeds

NTIA noted that “just as development of the CBRS band is providing important lessons that will facilitate the development of sharing in the 3450-3550 MHz band, the work done for 3450-3550 MHz may influence efforts to develop clearing in portions of the band or sharing across the band.”

The DoD is also working with the commercial industry to explore spectrum sharing technologies that could be used in the band.