AT&T and CTIA urged that the FCC rethink citizens broadband radio service rules and questioned the band's success, filing reply comments to an August NPRM (see 2411070032). But most commenters said the FCC should only tweak the band. CBRS advocates largely defended the model as a sharing success story. Interest in the proceeding was strong, with more than two dozen reply comments posted as of Friday.
CBRS
The Citizens Broadband Radio Service (CBRS) is designated unlicensed spectrum in the 3.5 GHz band created by the FCC as part of an effort to allow for shared federal and non-federal use of the band.
Peter Rysavy of Rysavy Research supported AT&T's arguments about reconfiguring the 3 GHz spectrum range, moving the citizens broadband radio service to 3.1-3.3 GHz (see 2410090037). That would open the 3.55-3.70 GHz band for wide-area, high-power licensed use “consistent with the adjacent 3.7 and 3.45 GHz bands,” Rysavy said. “Until practical and effective spectrum sharing technologies are available, exclusively licensed, full-power spectrum with wide radio channels remains the most effective resource for 5G networks with best results for consumers,” said a filing posted Thursday in docket 17-258. “Diligent efforts” by the National Spectrum Consortium and NTIA are making progress in developing methods of sharing spectrum, “but the realities of implementation are complex and development will take years.”
The Enterprise Wireless Alliance told the FCC it supports a change the American Petroleum Institute is seeking in rules for the citizens broadband radio service band (see 2410080030). EWA said it supports API’s suggestion that system administrators incorporate a general authorized access tier user algorithm that prioritizes spectrum access for small businesses and enterprise customers. CBRS is important to EWA members, said a filing posted Thursday in docket 17-258. “In a telecommunications world that focuses increasingly on commercial broadband services, the vital importance of enterprise entities to the nation’s economy and to its day-to-day functioning must be recognized,” EWA said: “Some of their wireless needs can be and are met on commercial networks, but many have core responsibilities that cannot be outsourced to the network of a third-party commercial provider.”
Spectrum for the Future Monday welcomed a NTIA report about usage growth in the citizens broadband radio service band (see 2411150021). The group said the report shows why the FCC shouldn't increase power levels available in the band (see 2411080032). “While some have suggested raising power levels or out of band emissions limits, that path would only jeopardize our ability to deliver greater innovation, wider-ranging use cases, and more consumer choice,” a spokesperson emailed: “The data shows that dynamic spectrum sharing is working, and we should maintain the unique properties that make CBRS the model for U.S. wireless leadership.”
NTIA told the FCC that utilization of the citizens broadband radio service band is up sharply and the three-tier shared band has been a success. “With CBRS, the Commission established a ground-breaking spectrum-sharing paradigm that has enabled commercial access to mid-band spectrum and has evolved to demonstrate the success of a collaborative partnership among stakeholders in the public and private sectors,” said a filing posted Friday in docket 17-258. CBRS deployments increased 270,621 from April 1, 2021, to July 1 this year, the filing said. Rural CBRS devices (CBSDs) “more than doubled, with an increase of 166,650 (160.6%)" and "67.5% of all CBSDs were in rural census blocks,” NTIA said. It found that 82.7% of all U.S. counties used at least one CBRS channel and 41% used all 15 as of July 1.
The Wireless ISP Association told the FCC many of its members use CBRS spectrum for reaching subscribers, and it opposes higher power levels for priority access license holders as a threat to general authorized access use of the band. Comments were due last week on an August NPRM in docket 17-258 (see 2411070032). Increasing maximum power levels “would substantially increase mutual interference between GAA users and even between GAA and PAL users on different channels,” WISPA said. “WISPA members should not be required to replace existing, relatively new equipment and purchase and deploy expensive high-powered base stations such as those used by mobile carriers in order to maintain their service areas.” Lockheed Martin said the FCC must coordinate major changes with DOD. “The current power levels represent a material, established feature upon which CBRS is premised,” Lockheed said: “Despite the essential role of pre-coordinated and established power levels, the Commission appears to have proposed these changes independently, and it is unclear what inter-agency coordination has or will occur and whether, even, there is support for such action by federal stakeholders.” Researchers at the University of Notre Dame noted that the use of CBRS is accelerating, even in small markets such as South Bend, Indiana, where the university is based. The researchers called for more reporting of interference metrics as measured on the ground by users. “When spectrum is being shared among multiple different users deploying networks in different verticals, the more information that can be shared, the better the performance for all,” they said. The Notre Dame researchers opposed adding a third category of devices that transmit at higher power levels than currently authorized, saying it would “exacerbate the secondary coexistence problem.” But Ericsson said the FCC should at least examine use of higher power levels. “Higher power levels for both [devices] and user equipment improve the efficiency of coverage to serve rural and underserved areas and reduce the cost of deployment,” Ericsson said: “Power levels can constrain certain use cases, especially wide-area commercial and enterprise networks. Enterprises like mining, large-scale agriculture, and media and entertainment companies need to support large outdoor coverage areas, and higher power levels can have a dramatic impact on enabling efficient deployments.” Increasing transmit power levels “will improve coverage, especially in rural areas, increase network efficiency, and reduce equipment and network design and deployment costs” and “can be achieved without causing harmful interference to incumbents or other spectrum users,” Federated Wireless said. Federated noted transmit levels are much lower than in the adjacent 3.45 GHz and C-band. “This discrepancy creates a significant coverage imbalance between CBRS and these adjacent bands, which undermines CBRS’s competitive capability and restricts its potential for expanded service, particularly in rural and underserved areas.”
The FCC got dozens of comments on an August NPRM from wireless carriers, tech companies and others on further changes to rules for the citizens broadband radio service band (see 2408160031). In filings posted through Thursday in docket 17-258, commenters disagreed sharply on a proposal by carriers to more closely harmonize CBRS rules with those for the adjacent 3.45 GHz and C-band.
Federated Wireless has withdrawn its request for a waiver of rules that require environmental sensing capability (ESC) systems to protect federal incumbents in Florida in the citizens broadband radio service band from harmful interference. It said in a docket 15-319 filing posted Wednesday the waiver is no longer needed as ESC sensor redundancy lost during Hurricane Milton has been restored. Federated and Google received waivers in advance of the hurricane's landfall (see 2410080058).
Fixed satellite service earth station licensees qualified for protection from citizens broadband radio service have until Dec. 2 to renew their licenses so that their registration is valid in 2025, according to an FCC Wireless Bureau public notice Friday. Incomplete registrations as of Jan. 1 may be deactivated or deleted, and the earth station site won't merit protection by spectrum access system administrators, it said.
Industry officials continued questioning AT&T’s Wednesday proposal that calls for major changes in how 3 GHz, including the citizens broadband radio service band, is configured (see 2410090037). Monisha Ghosh, University of Notre Dame engineering professor and former FCC chief technologist, said AT&T's proposal leaves some questions unanswered. While in principle it’s “desirable to have high-power and low-power users separated by one boundary, the AT&T proposal doesn’t address how the existing Navy radars in the CBRS band will be protected” or “relocated and how spectrum sharing in 3.1-3.45 GHz will be implemented,” Ghosh told us, noting there are now 120 different kinds of radar in the band. Ghosh warned against drawing conclusions before the administration completes its study of the lower 3 GHz band called for in the national spectrum strategy. Moreover, Ghosh disagreed with AT&T that CBRS is "underutilized.” Relocating CBRS devices into another band that’s not an existing 3rd Generation Partnership Project band wouldn’t be a “trivial” problem, she said. Meanwhile, Public Knowledge Senior Vice President Harold Feld wrote in an email, “When you have a hammer, everything looks like a nail,” and when you’re a carrier “everything looks like it should be optimized for mobile broadband.” Feld added, “CBRS was designed to permit new kinds of innovation by different actors, such as stadiums, large warehouses, ports, or enterprise customers looking to run their own private networks.”