11/6 PISC Comments Urging FCC to Preserve CBRS Band’s Innovative Promotion of Diverse, Local, Low-Power Uses and Spectrum Sharing

The Wireless Future Project at New America’s Open Technology Institute (OTI) filed comments on behalf of the Public Interest Spectrum Coalition (PISC) regarding a proposed rulemaking from the Federal Communications Commission (FCC), which seeks to update the Citizens Broadband Radio Service (CBRS).

PISC groups signing the Comments included:

• OTI
• Public Knowledge
• American Library Association
• Benton Institute for Broadband & Society
• Schools Health & Libraries Broadband (SHLB) Coalition
• Consortium for School Networking (COSN)
• Access Humboldt
• X-Lab

Our groups strongly oppose proposals that would substantially increase the maximum allowable power levels for users in the CBRS band of spectrum (3550-3700 MHz), for several reasons:

• Changing the current rules to facilitate the business model of major mobile cellular providers (which already use the vast majority of full power spectrum) is virtually certain to undermine the actual purpose of CBRS—promoting diverse, local, low-power uses—as it will severely impact the spectrum’s availability and use, especially for General Authorized Access (GAA) tier users, such as schools, libraries, hospitals, and other community institutions.
• Enabling more and more operators to turn up their power levels—either to expand coverage or, more likely, to preemptively defend themselves against other GAA users, who have increased their power or could be expected to do so in the future—will make CBRS inhospitable for the majority of GAA users and use cases, as it will facilitate the expansion and eventual overlap of coverage areas, leaving fewer GAA channel assignments available, magnifying aggregate interference, and diminishing efficient spectrum re-use.
• Opening the door to a sudden influx of higher-power users would not only discourage schools, libraries, hospitals, and other community institutions from developing new private networks, but also burden those who have already developed private networks with the unexpected costs that buying new, higher-power technology would entail.
• Adopting such a dramatic rule change would disrupt standing agreements between the Department of Defense, FCC, NTIA, and industry to balance the priority of promoting greater spectrum access with the necessity of adequately safeguarding Naval operations, requiring an overhaul that would severely upend the unprecedented collaboration and fragile trust these stakeholders have established.

Our groups also oppose proposals to increase the CBRS in-band Out Of Band Emissions (OOBE) limit from -25 dBm/MHz to -13 dBm/MHz, as a substantially higher in-band OOBE limit will increase interference in the band for GAA users and others who relied on the current rules when planning their existing CBRS deployments.

Finally, our groups believe the FCC should implement rule changes to increase the availability and transparency of information about Citizens Broadband Radio Service Devices (CBSD), as well as the breadth and scope of CBSD information provided to Spectrum Access Systems (SASs), which coordinate private sector access to protect incumbent users (such as the U.S. Navy). The utility and efficiency of the band for GAA users could be increased enormously by:

• Allowing band users to know where nearby CBSDs are located, their technical characteristic, and what frequencies they have been granted to use (and, ideally, what channels they actually are using).
• Allowing (and possibly requiring) SAS administrators to disclose the boundaries of Priority Access License (PAL) Protection Areas to facilitate GAA-PAL coexistence.
• Requiring CBSDs to report their actual channel use back to the SAS, as well as possibly other readily collected data about the interference environment.