AT&T spells out its concerns about census tracts in 3.5 GHz band

AT&T visited FCC headquarters to explain how census tracts are problematic and emphasize the 3.5 GHz Citizens Broadband Radio Service's (CBRS) need for larger licensed areas. 

AT&T executives met with FCC officials on April 3 to discuss the engineering and cost challenges of deploying Radio Access Network using census tracts as the baseline license size, according to an ex parte filing (PDF). The current rules call for census tracts but the FCC is considering changing that.

AT&T explained that it enlisted CommScope to analyze the practical impact of the CBRS interference protection rules given the small market areas. They found that to cover the border areas of census tracts, licensees must severely limit their power and deploy many more Citizens Broadband Service Devices than what may actually be needed, resulting in substantial increases in equipment and maintenance costs, more backhaul and more siting approvals to be ascertained.

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AT&T suggested that larger license sizes, such as those based on Partial Economic Areas (PEAs), would permit deployments using higher power for coverage and limit the impact of border areas. The PEA size is what CTIA has been advocating (PDF) for.

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But census tracts are precisely what smaller carriers and some in the electric/utility industry want. Companies like GE, Southern Linc and Union Pacific have told the commission that with census tract licensing in the CBRS band, they expect to be able to bid vigorously at auction to gain localized spectrum access that aligns with their geographically targeted deployment plans. That’s because with their own licensed, interference-protected 3.5 GHz spectrum, industrial entities will be able to “self-provision” Industrial IoT (IIoT) connectivity over geographically targeted, private TDD-LTE networks. Essentially, they would be able to design systems that match their grids, port areas, pipelines or railroad systems.

They explained that if the FCC adopts PEA or county licensing, it will not be economically rational for industrial/utility entities to outbid wireless carriers for licenses covering territory that extends far beyond their geographically targeted, localized facilities. Thus, they argue, that would result in a delayed and diminished scale and scope for IIoT. These entities say that using their own license spectrum is a better option for them than obtaining services from traditional telecom carriers or carrier MVNOs.

Efforts to reach some kind of compromise have been underway by industry, which would make the FCC’s job easier. The commission approved the CBRS rules back in 2015 but CTIA and T-Mobile petitioned the FCC last year asking for specific rule changes, arguing that they were necessary in part to keep the U.S. competitive in 5G. Most of the debate has centered on the PALs as opposed to the unlicensed General Authorized Access portion of the band, which many expect to get put to use before the end of this year.