How spectrum sharing works

NTIA looks at spectrum-sharing feasibility

The spectrum currently used by the Departments of Defense and Homeland Security for coastal and spot radar applications -- between 3100-3550 megahertz --  “is a good candidate for potential spectrum sharing” between  federal and commercial  applications, according to a new report from the National Telecommunications and Information Administration.

That “mid-band” spectrum analyzed in NTIA’s study is just below spectrum now used for commercial deployments for Citizens Broadband Radio Service (CBRS) in the 3550-3700 MHz range.

NTIA is mandated to find federal spectrum to share for commercial use. The 2018 MOBILE NOW Act called for NTIA identify 255 megahertz for fixed and mobile wireless broadband use by 2022, with both unlicensed use and licensed use getting at least 100 MHz.

Last September, the Federal Communications Commission approved the first initial commercial deployments for CBRS. CBRS users share frequency allocations with incumbent DOD shipborne radar applications. NTIA had recommended that the upper 100 megahertz portion in that spectrum band be made available for commercial wireless broadband use, outside of certain coastal and test and training areas.

Commercial service providers now operating on that spectrum include AT&T, Boingo, Charter Communications and Verizon. Those providers use a three-tiered sharing model that gives incumbent DOD users priority access when needed, as well as licensed and unlicensed access for commercial private and general access services.

NTIA’s new study said the 3100-3550 MHz spectrum offers similar shared-use opportunities, but warned the spectrum has some issues that need further study. For instance, NTIA said sharing spectrum for commercial use at 3450 MHz could be problematic because of air defense, missile and gunfire control, bomb scoring, battlefield weapon locations, air traffic control, and range safety applications that use those frequencies.

More study of the entire band, however, is needed before further action, according to NTIA.

This article was first posted to FCW, a sibling site to GCN.

About the Author

Mark Rockwell is a senior staff writer at FCW, whose beat focuses on acquisition, the Department of Homeland Security and the Department of Energy.

Before joining FCW, Rockwell was Washington correspondent for Government Security News, where he covered all aspects of homeland security from IT to detection dogs and border security. Over the last 25 years in Washington as a reporter, editor and correspondent, he has covered an increasingly wide array of high-tech issues for publications like Communications Week, Internet Week, Fiber Optics News, magazine and Wireless Week.

Rockwell received a Jesse H. Neal Award for his work covering telecommunications issues, and is a graduate of James Madison University.

Click here for previous articles by Rockwell. Contact him at [email protected] or follow him on Twitter at @MRockwell4.


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