5G advocates look to spectrum sharing

Federal agencies' traditionally tight hold on their wireless spectrum is loosening, as new technologies demand fresh approaches to leveraging the increasingly scarce resource for both government and industry, according to top federal agency spectrum resource officials.

The Pentagon, said Col. Frederick Williams, director spectrum policy and programs in the Defense Department CIO's office, is looking for "cognitive cohabitation" on sprawling DOD spectrum holdings with commercial providers whenever possible. The agency's spectrum resources traditionally have been carefully sequestered over the decades, he said at the National Telecommunications and Information Administration (NTIA) spectrum policy symposium on Sept. 10.

That era, he said, is largely over, as commercial wireless services take up an increasingly large percentage of the national spectrum resource. The tension felt by federal agencies tasked with handing over some spectrum for commercial use has dissipated, he said. New technologies, particularly commercial 5G, can revolutionize both agency and commercial applications, he said.

Last fall, the White House rolled out a proposal to create a national spectrum strategy not only to ensure the U.S. leads in emerging technologies such as 5G, but to better coordinate spectrum use among federal and commercial entities. In August, the NTIA asked federal agencies to assess their spectrum holdings in detail and report back.

Programs such as the Citizens Broadband Radio Service that shares spectrum in the 3.5 GHz band with both incumbent Navy radar systems and commercial users are the foundation of a new era in spectrum sharing, according to Williams. The test of the CBRS program, he said, shows how "sense and avoid" radio systems can work within bands.

The flourishing unmanned aircraft market has changed how the Federal Aviation Administration looks at its spectrum holdings and how it will work to free up the resource, said Ian Atkins, director of spectrum strategy and policy at the agency. When small commercial drones took to the skies by the hundreds of thousands, and then millions, Atkins said the small aircraft couldn't operate in the traditional "aviation spectrum" that commercial aircraft use, nor take advantage of traditional flight management systems that commercial aircraft use. They forced a new perspective, he said.

As a result the FAA took a holistic view of spectrum use throughout its operations, using a fundamental measuring stick of spectrum impact on the agency's primary air safety mission, he said.

"We're not planning on increasing our spectrum use. Our spectrum use is expected to go down," Atkins said at the NTIA conference. Because there will never be enough "aviation spectrum" to support the exploding number of small drone aircraft, the answer, he said, is considering spectrum as a flexible resource, once safety parameters are met.

For instance, private drones that typically fly at very low altitudes can tap into a pool of shared radio spectrum set aside by the FAA and privately managed by a commercial entity, he said. Commercial aircraft flying at 40,000 feet, he said, have a completely different set of spectrum and safety needs. Understanding those differences and ordering spectrum use based on them, he said, has been a key to managing FAA spectrum in a complex environment.

Some federal spectrum allocations don't lend themselves to shared use, however, like some satellite applications and big programs such as the Artemis moon mission, said RJ Balanga, NASA senior regulatory and policy advisor, space communications and navigation and human exploration and operations office. Additionally, 5G bandwidth is adjacent to active/passive frequencies used by some weather satellites that measure cloud cover and air moisture using specific bandwidth that isn't easily changed, he said.

All the agency officials are looking to the White House's planned release of a national spectrum strategy in the coming weeks to help them further hone their approaches to both sharing and using their spectrum more effectively and efficiently.

Deputy Commerce Secretary Karen Dunn Kelley told the conference the White House will release the strategy "later this fall," and it "will clarify our long-term approach to planning, innovation and collaboration among policy makers, federal agencies and commercial industry."