WASHINGTON — An interagency dispute about the use of a spectrum band for weather forecasting versus terrestrial wireless services illustrates the need for the federal government to reform its spectrum management processes, a report concluded.
The Government Accountability Office issued a report July 19 that concluded that various federal agencies need to strength ways of collaborating with one another to avoid repeating a dispute that spilled into public view in 2019 about allowing 5G services at 24 gigahertz despite concerns it could interfere with water vapor observations critical for weather forecasting on an adjacent band.
Both NASA and the National Oceanic and Atmospheric Administration objected to the FCC’s plans for making that band available for 5G, saying the FCC’s interference limits were not sufficient. The FCC auctioned portions of the 24 gigahertz band, but the World Radiocommunication Conference later that year adopted more stringent interference standards that the FCC is still evaluating.
The GAO recommended improved coordination among those agencies and others, such as the National Telecommunications and Information Administration. It also recommended NOAA and NASA develop procedures for providing technical input for spectrum rulemaking, noting that the agencies took years to weigh in on the potential interference issues at 24 gigahertz. NASA has already taken steps to provide more timely responses.
“The United States’ spectrum management process failed our nation’s forecasters,” Rep. Eddie Bernice Johnson (D-Texas), chair of the House Science Committee, said at a July 20 hearing by her committee on the topic. Johnson and Rep. Frank Lucas (R-Okla.), ranking member of the committee, requested the GAO report.
She and others on the committee called for implementing recommendations to better coordinate spectrum. “If we can establish a more coordinated, whole-of-government approach to spectrum management, we can enable U.S. telecommunications leadership and protect important Earth and space science observations,” she said.
Both members and witnesses were critical of the FCC, which pressed ahead with the 24 gigahertz auction despite concerns interference would adversely affect the accuracy of forecasts. “As a scientist, it is discomforting that the FCC can conduct rulemaking without studies that could have an impact on another agency to accomplish its congressionally directed mission,” said Jordan Gerth of the University of Wisconsin’s Space Science and Engineering Center, one of the witnesses at the hearing.
Scientists remain worried that the use of the 24 gigahertz band for 5G services could interfere with weather forecasting. Satellites make passive measurements of emissions of water vapor molecules in the band, and have no recourse in the event of interference. “It’s like trying to hear a whisper in San Francisco while standing 500 miles away in San Diego,” said David Lubar of the Aerospace Corporation.
“The laws of physics dictate these passive frequency bands. They’re a gift of nature and, therefore, there is no alternative other than protection,” said Bill Mahoney, associate director of the National Center for Atmospheric Research.
While the 24 gigahertz rulemaking prompted the report, some members of the committee used the hearing to express frustrations about other aspects of FCC rulemaking, such as its approval of an application by Ligado to offer 5G services on another band despite warnings from the Defense Department and other agencies that it could interfere with GPS signals. The FCC was not represented at the hearing
“Do decisions at the FCC bias terrestrial communications services over space-based or satellite communications?” asked Rep. Randy Weber (R-Texas).
“On spectrum issues, we do find a bias based on economic rationales,” said Jennifer Manner, senior vice president of regulatory affairs at EchoStar. She cited as an example a separate FCC proceeding that took away some Ka-band spectrum that had been used for satellite gateways for 5G applications, even though the FCC is now rethinking whether that spectrum is useful for 5G. “So yes, I have been seeing a bias on that.”
“We all support the deployment of 5G,” Lucas said. “But spectrum allocation decisions cannot be about choosing connectivity over forecasting. We have a responsibility to seek a balance between the needs of the federal users and noncommercial users of spectrum with commercial users of spectrum.”