NTIA Report Looks at 5G in 3450-3550 MHz Band

NTIA released a report Monday calling for further study but saying federal agencies may be able to share the 3450-3550 MHz band, which is directly below the 3.5 GHz citizens broadband radio service spectrum (see 2001270025). DOD assisted in preparing the report. Federal operations in the band “include shipborne, airborne, and land-based systems -- primarily radars,” blogged Charles Cooper, associate administrator of the NTIA Office of Spectrum Management: “Our report points to a clear possibility for real time spectrum sharing that would protect these critical missions, while providing attractive opportunities for commercial business.” The next step is studying how often each of the federal systems is used, and then developing “mechanisms for reliably informing commercial operations when federal systems are operating nearby,” Cooper said: "This 100 MHz of spectrum should be well suited for realizing 5G’s promise of higher throughput and lower latency operations." The report says the band gets significant federal use, with shipborne radars operating at more than 20 ports along the Atlantic, Pacific and Gulf coasts. Some airborne systems operate nationwide; other systems are limited, the report said: “The ground-based radars operate at over one hundred locations, including many near high-population areas. In addition, DOD continues to deploy systems at additional locations and to develop new systems for operation in the band.” Some aspects “of the systems are classified, which reduced the ability for the report to be as transparent regarding the analysis as otherwise possible,” the document says. Frequency- or geographic-based sharing approaches “would result in significant restrictions on commercial services, in terms of emitter power limits and exclusion zones, making sufficient access for viable commercial applications unlikely,” the report found: “A dynamic, time-based sharing mechanism could present a potentially attractive approach to both protecting federal systems and providing viable commercial operations. Commercial operations would be contingent on spectrum availability, which will depend on the frequency, time, and location of federal system operations.” It’s no surprise NTIA found “extensive” military use of the band requiring protection, said Michael Calabrese, director of the Wireless Future Program at New America. “The good news is that the report’s technical findings suggest the spectrum could be shared nationwide by low-power, indoor operations, as well as outdoors away from the coasts,” he told us: “It appears that shared use could be supported by expanding on the database coordination approach that manages sharing with the Navy in the adjacent band under the new CBRS framework that became fully open for effectively unlicensed use today. Adding this band to CBRS looks like it will be the fastest and most efficient way to put it to use for 5G-quality connectivity.”