Security and Resilience (Cyber and Physical)

APPA, Other Groups Seek FCC Rulemaking for 6 GHz Low Power Indoor Devices

The American Public Power Association (APPA) and a coalition of critical infrastructure industries on Dec. 7 asked the Federal Communications Commission (FCC) to adopt a rulemaking that develops new rules for 6 GHz low-power indoor (LPI) devices.

While seeking a new rule, APPA and the other industry groups also sought an immediate stay of equipment authorization of unlicensed 6 GHz LPI devices. The stay, pending development of rules that are proven to avoid interference from these devices, will prevent harm to currently licensed microwave systems in the 6 GHz band.


The FCC’s Report and Order (R&O) to open the 6 GHz band of spectrum to unlicensed usage went into effect in July 2020. 

The R&O allows two types of unlicensed operations -- low powered indoor use and outdoor use protected with an automated frequency coordination (AFC) technology.

A broad coalition of incumbent license holders filed extensive comments raising concerns about interference to operations that could result from opening the band to unlicensed users and requesting further testing and protections from the FCC. Those concerns and comments were not addressed, leading APPA and others in the electric sector to file legal challenges.

In April 2021, investor-owned utility Southern Company and the Electric Power Research Institute (EPRI) acquired 6 GHz devices available on the market to conduct real world testing on impacts to electric utilities.

They operated them near a Southern Company microwave link operating between Fortson and Columbus, Ga., using the FCC thresholds for reportable interference. The tests showed that, even at low powered indoor use, the unlicensed devices would “cause harmful interference to licensed fixed microwave systems” greater than the FCC’s acceptable levels. This report was filed and presented to FCC staff. 

Petition For Rulemaking

The petition for rulemaking states that the current rules for LPI use are flawed because they rely on modeling and not real-world data and, as such, must be modified to protect incumbent license holders from harmful interference.

The petition further states that LPI devices should be controlled by an AFC system, the FCC should adopt rules for licensees to recover costs from monitoring and mitigating potential interference created by unlicensed systems, and the FCC should conduct independent testing to determine if new rules should be developed for standard power devices.

“Recent real-world tests have determined that 6 GHz LPI devices will cause harmful interference to licensed microwave systems in the band, due in part to beacon signals that will transmit constantly and thus endanger the functioning of services to public safety and critical infrastructure industries and seriously degrade, obstruct, or repeatedly interrupt their radio communications services,” the groups said.

“These tests also demonstrate that the data and the assumptions for the Commission’s rules for 6 GHz LPI devices are fundamentally flawed.”

The FCC should therefore exercise its rulemaking authority “to revise the rules and conduct open and transparent testing to prove these rules effectively prevent interference to licensed microwave systems.  In that regard, the Commission should require 6 GHz LPI devices to be controlled by AFC or use some other interference protection mechanism.”  

The groups also said that the FCC should establish a mechanism for cost recovery by incumbents to reimburse them for mitigating and resolving interference from unlicensed 6 GHz operations. 

They said that this is consistent with the Commission’s emerging technologies framework and Commission precedent. 

“Also, due to the flawed data and assumptions upon which the Commission relied, the Commission should conduct independent tests of standard power access devices to determine if new rules need to be developed that will prevent interference from these devices to licensed microwave systems in the band.”

Request For Stay

The request for stay asks the FCC to put a temporary halt on the equipment authorization of unlicensed 6 GHz LPI devices pending the adoption of rules that are proven to prevent interference to licensed systems.

The stay is necessary to prevent the imminent risk of irreparable harm from the interference that these unlicensed 6 GHz LPI devices are certain to cause to incumbent licensed systems in the band, such as electric utility SCADA and other system monitoring equipment. 

A temporary stay will not significantly harm the interests of other stakeholders, “and the public interest favors granting the stay immediately to protect public safety and critical infrastructure industries who provide essential services to the public at large” the petitioners stated.

APPA was joined in the filings by:

  • The Utilities Technology Council
  • American Gas Association
  • Edison Electric Institute
  • American Petroleum Institute
  • American Water Works Association
  • National Rural Electric Cooperative Association
  • International Association of Fire Chiefs
  • The Association of American Railroads
  • APCO International
  • Nuclear Energy Institute and
  • The National Public Safety Telecommunications Council.