White House and Department of Defense officials have announced plans to commercialize another 100 megahertz of highly desired midband spectrum for terrestrial 5G use, with an auction happening as soon as next year.
The airwaves from 3.45 GHz-3.55 GHz are adjacent to the Citizens Broadband Radio Service spectrum that is already in commercial use, with Priority Access Licenses being auctioned now.
“In mid-April, the White House and DoD met to discuss what could be done quickly to make more mid-band spectrum available for 5G in the 3 gigahertz band range, commonly known as mid-band, which is paramount to maintaining American leadership in 5G,” said Dana Deasey, CIO for the Department of Defense, in a statement to the press. “As a result, the America’s Mid-Band Initiative Team (AMBIT) was established and worked on an unprecedented 15-week schedule to make 100 megahertz of contiguous mid-band spectrum available in the 3450-3550 MHz band for 5G by the end of the summer.”
Service rules for the band will still need to be set by the Federal Communications Commission, but the White House says that an auction could be held in December 2021, with the spectrum in use by 2022.
“Through the hard work of the AMBIT, we expect these rules to be similar to AWS-3, where for the most part the spectrum will be available for commercial use without limits, while simultaneously minimizing impact to DoD operations,” Deasey said. “DoD is preparing a spectrum relocation fund transition plan to allow for implementation of the sharing plan while minimizing risks to DoD operations. DoD is proud of the success of the AMBIT and is committed to working closely with industry after the FCC auction to ensure timely access to the band while protecting national security.”
Interest in the band for sharing dates back to a 2010 ten-year plan to open up 500 megahertz of spectrum for commercial use, with renewed interest under a 2018 mandate to examine the possibility of spectrum-sharing in a broader range from 3.1-3.55 GHz. The National Telecommunications and Information Administration recently reported to Congress on the feasibility of sharing in the band, saying that the section of that spectrum between 3.45-3.55 GHz was identified as having “the highest probability of being able to accommodate sharing with commercial wireless services in a relatively short timeframe.”
The band, according to a recent feasibility report from NTIA — which was leveraged by AMBIT — is “critical” to Department of Defense (DoD) and Department of Homeland Security (DHS) radar operations, with DHS operating fixed and transportable radars in the band and DoD operating high-powered defense radar systems that include fixed, mobile, shipborne, and airborne platforms for air defense, missile and gunfire control, bomb scoring, battlefield weapon locations, air traffic control, and range safety. In terms of geographic area, federal operations span the entire United States and its territories, with some airborne systems operating nationwide, more than 100 locations for ground-based radars and shipborne radars that operate in more than 20 ports as well as along the U.S. coasts.
The DoD has already conducted a related 3450-3550 MHz Technical Study considered all federal systems in the band, potential aggregate interference to those systems under two different hypothetical commercial deployments and three sets of power levels for each, including “both the relatively low-power operation currently permitted for commercial operations in the adjacent band above 3550 MHz and the higher power levels that industry representatives have indicated are optimal.” While commercial systems at 3.45-3.55 GHz would generate interference with the existing ones, the study found, it “nonetheless concludes that, with a transition of nationwide aeronautical systems to alternative frequencies, proper interference mitigation mechanisms, and further study, spectrum sharing may be technically feasible for all or portions of the 3450-3550 MHz sub-band, including at all the power levels analyzed.”
The 2010 ten-year plan that highlighted this spectrum as a potential sharing candidate also jump-started the development that led to the commercialization of the three-tiered sharing framework for CBRS. So why not take the same approach that has been realized with CBRS? The NTIA report says that while the work done for CBRS “is directly applicable to the establishment of sharing between commercial wireless and shipborne radars in this band, it is less relevant to the development of appropriate systems to protect the other – ground-based and airborne – systems in the band. This is partly because industry-managed monitoring stations outside military installations are inherently problematic from an operational security perspective and many more would be required due to the large number of ground-based radar sites, and partly because there are unique technical challenges to monitoring airborne operations.” NTIA’s report had floated the idea of a government-operated Spectrum Access System (SAS)-type approach, in lieu of the commercial SASes that manage the CBRS band.
FCC Chairman Ajit Pai praised the move to make the spectrum commercially available, calling it a “key milestone in securing United States leadership in 5G.”
He added, “Together with the spectrum being made available for 5G in the C-band as well as the 3.5 GHz band, we are now on track to have a 530-megahertz swath of mid-band spectrum available for 5G from 3.45 to 3.98 GHz. The FCC looks forward to moving quickly to adopt service rules for the 3.45 GHz band and then hold an auction to bring this prime mid-band spectrum to market.”
“Opening up this critical block of mid-band spectrum for full power commercial operations will enhance U.S. competitiveness in the 5G ecosystem,” said CTIA President and CEO Meredith Attwell Baker. “We applaud the White House and Pentagon for finding ways to promote our nation’s leadership of the emerging 5G economy while safeguarding vital defense operations.”
The Wireless Internet Service Providers Association likewise said that finite spectrum resources “must be shared if Americans are to gain the full benefits of wireless broadband. The CBRS band shows that a viable framework can be employed to do so – one which both protects national security and allows for commercial use. We want to thank all involved for working through the numerous complex technical arrangements to make available this valuable mid-band spectrum. This sharing will benefit Americans, keeping them safe on the home front, and providing more of the fuel providers and the industry need to bring broadband to hungry consumers.”
