Why does 6GHz need to be protected?

Marlene H. Dortch, Secretary
Federal Communications Commission
445 12th Street, S.W.
Washington, DC 20554

Re: GN Docket No. 17-183, Expanding Flexible Use in Mid-Band Spectrum Between 3.7 and 24 GHz
Ex Parte Communication

Dear Ms. Dortch:
Apple et al. proposes to deploy large numbers of high-powered, uncontrolled unlicensed devices (RLANs) in the 6 GHz microwave bands. We oppose.

We are writing to you express our opposition to the proposals contained in ex parte “Frequency Sharing for Radio Local Area Networks in the 6 GHz Band (January 2018),” prepared by RKF Engineering Services, LLC on behalf of Apple Inc., Broadcom Limited, Cisco Systems, Inc., Facebook Inc., Google LLC, Hewlett-Packard Enterprise, Intel Corporation, Microsoft Corporation, MediaTek Inc., and QUALCOMM Incorporated.

We agree wholeheartedly with the opposition comments made by AT&T and the FWCC (Fixed Wireless Communications Coalition). The 6GHz band is the work horse of the fixed link world in the United States. Its properties are unique in American terms; no other band can support such long links at such high availability. 7GHz and 8GHz are obviously reserved for federal use and 10GHz only supports up to 5MHz channels. The importance of the role of 6GHz, therefore, cannot be overestimated. Further, 6GHz provides critical communications to support both public safety and national infrastructure. AT&T’s ex parte of March 16th points out that the band is home to almost 100,000 microwave links. At a relatively conservative estimate of $125,000 per link for CapEx, $12.5B is invested in the 6GHz band. The value of the work completed by these links on a daily basis, over a matter of years, is more difficult to estimate but likely goes well beyond the value of the hardware installed, especially given the number of public safety and utility deployments in this band.

The FWCC study filed on March 13th, 2018, discredited the study by RKF Engineering by showing its claimed results do not follow from its assumptions, and showed in detail that the RLANs considered by RKF in fact would cause widespread interference. Average distribution of power, population of RLANs and height at which RLANs may be installed is unrealistically kind to any technical analysis of unlicensed services in a carefully coordinated and licensed band. It is our opinion that unlicensed/unregistered RLANs cannot coexist with licensed fixed links and we are greatly concerned that it would be virtually impossible for the FCC to locate any sources of interference in order to provide licensed fixed links with the protection they are entitled to.

Respectfully submitted

Ola Gustafsson, Senior Vice President
AVIAT NETWORKS U.S. INC.
860 N. McCarthy Blvd, Suite 200
Milpitas
CA 95035

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