NSMA to FCC: Don’t buy what RKF study is selling

The National Spectrum Management Association does not agree with an RKF study. (Pixabay)

An organization with the middle name “Spectrum Management” is telling the FCC to reject an RKF study submitted by some big-name tech companies that are pushing sharing in the 6 GHz band.

“We have an interest in the spectrum conservation impact of the RKF study,” the National Spectrum Management Association (NSMA) told (PDF) the FCC. “Our organization promotes efficient sharing of spectrum allocated to all services. We believe the RKF study has serious deficiencies,” many of which were addressed by the Fixed Wireless Communications Coalition (FWCC) in a previous filing.

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But the NSMA has some additional concerns, including assumptions that it said RKF incorrectly made about Part 74 Pickup Broadcast Auxiliary Service (BAS) operations in the 6.425-6.525 GHz and 6.875-7.125 GHz bands. Like some other commenters, the NSMA also is peeved about the lack of transparency in the report; it contends the study never spells out any analysis.   

“We are disturbed that the report does not even give the information that would let us attempt to replicate their conclusions—which to us are counter-intuitive,” NSMA said. “They see no significant interference where we see almost inevitable interference.”

Earlier this year, representatives from Apple, Broadcom, Cisco Systems, Hewlett Packard Enterprise, Facebook, Google, Intel, MediaTek, Microsoft and Qualcomm met with FCC representatives and presented the study (PDF), prepared by RKF Engineering Solutions, which analyzed sharing between unlicensed operations in the 6 GHz band and existing services.

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The tech companies said the study demonstrates unlicensed services can coexist successfully with the range of licensed services present in the 6 GHz band, and they hope the study helps the FCC release more unlicensed spectrum in an increasingly crowded Wi-Fi ecosystem.

But the FWCC’s analysis showed the uncontrolled distribution of unlicensed devices—in the numbers and at the power levels RKF studied—would indeed cause widespread harmful interference to fixed microwave receivers. FWCC is a coalition of companies, associations and individuals involved in terrestrial fixed microwave communications.

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AT&T also added (PDF) its voice to those opposed to the RKF study, saying it, too, found flaws in the report that “drastically undermine” the study’s conclusion, including underestimating the interference to fixed microwave services by using conservative propagation and antenna models.