In recent joint comments submitted to the Federal Communications Commission (FCC), the American Public Power Association and several other trade groups argue that the FCC should refrain from further expanding unlicensed operations in the 6 GHz band “until such time that additional testing has been conducted to prove that unlicensed operations will not cause harmful interference to licensed microwave systems.”
APPA and the other groups submitted the June 29 comments in response to a Further Notice of Proposed Rulemaking (FNPRM) related to the unlicensed use of the 6 GHz band.
Along with APPA, the other groups joining in the comments were the National Rural Electric Cooperative Association (NRECA), American Gas Association (AGA), American Water Works Association (AWWA) and the Utilities Technology Council (UTC).
The FCC issued a Report and Order (R&O) to open the 6 GHz band of spectrum to unlicensed usage back in May. The rules will go into effect on July 27.
The R&O allows two types of unlicensed operations, low powered indoor use and outdoor use with automated frequency coordination (AFC) technology.
The FCC asserts that these are tailored to protect incumbent services that operate in distinct parts of the 6 GHz band.
However, despite the objections of a number of parties, including incumbent license holders and federal agencies regarding the lack of adequate protection from interference afforded in the underlying R&O, the FCC’s FNPRM seeks to go further by allowing more unlicensed operations in the band.
The FNPRM sought comments on whether to further permit unlicensed devices, operating both indoors and outdoors, across the entire band at power levels low enough to prevent interference to licensed services and whether to allow for unlicensed access points that are restricted to indoor operation to operate at a power level over what is set by the R&O.
In addition, the FNPRM sought comments on whether to permit access points that operate under the control of an AFC system in two sub-bands (the 5.925-6.425 GHz and 5.512-6.875 GHz) for mobile applications.
APPA, other groups weigh in
The groups pointed out that two years have passed since the FCC initiated this rulemaking proceeding. During that time frame, the Commission received numerous comments in opposition and studies that showed the impacts interference will have on critical infrastructure from unlicensed usage.
“Now, less than two months after adopting its Report and Order, the Commission proposes additional rules and invites comments on expanding unlicensed operations in the 6 GHz band. At best, this is premature without further experience in a real-world environment; at worst, it recklessly disregards the risk to critical safety and control systems that allow utilities to safely, reliably and securely deliver electric, gas and water services to 330 million Americans.”
Loss of energy and water utility services “can have widespread effects on public safety, the economy, and national security. Moreover, it will affect not only utilities; it will affect any critical infrastructure industry and public safety agency that relies on the 6 GHz band for mission critical communications,” APPA and the others said in their comments.
The groups said that the FCC should refrain from very low power authorization across the band until testing has been done and real world impacts has been determined regarding current operations. Further, the Commission should not allow an increase in the power level for low power indoor devices because it further increases the probability of harmful interference.
In addition, APPA and the other groups said that authorization of both mobile standard-power devices or higher power standard-power devices should not be allowed because the Commission itself recognizes the potential they create for interference, and specifically for mobile devices, the greater complexity they create for an effective AFC.
The groups also said that the FCC should engage with a multi-stakeholder group to ensure the “the development of effective solutions for the implementation of AFC to protect licensed microwave systems and resolve instances of interference and to test low power indoor devices prior to commercial deployment to ensure that they will not cause interference to licensed microwave systems.”