AT&T Warns T-Mobile US, Starlink May Disrupt Terrestrial Cellphones

The race to deliver mobile phone services via satellite may have turned nasty, with AT&T filing a petition with the US Federal Communications Commission (FCC) to block rival T-Mobile US from operating its planned service in partnership with satellite company Starlink.

AT&T submitted remarks in a filing [PDF] dated May 18 saying it was vital that so-called supplemental coverage from space (SCS) services are not allowed to interfere with existing terrestrial wireless services.

The company was responding to an FCC public notice seeking comments on a joint request [PDF] from Starlink parent SpaceX and T-Mobile for the authority to deploy SCS services to supplement T-Mob’s terrestrial network. The two companies intend to deliver this using T-Mobile’s Broadband PCS G Block spectrum, according to the filing.

SpaceX and T-Mobile announced their plans for a satellite phone service last August, saying their intention was to provide cellphone coverage for remote locations across the US and potentially elsewhere, and to achieve this using standard phones.

AT&T says it has an interest in this matter as a license holder of frequencies adjacent to the specific block of spectrum in question, and is concerned that satellite-based phone operations may therefore disrupt the delivery of terrestrial wireless services, from which we can infer that it is referring to its own network services.

“Americans rely on wireless connectivity to access telehealth platforms, educational resources, important government services, and more,” the filing states. “In evaluating potential SCS deployments, the Commission must prioritize protecting these foundational terrestrial networks,” the company insists.

The FCC’s rules do not permit SpaceX’s proposed use of T-Mobile’s terrestrial spectrum, AT&T maintains in the filing, adding that “the Applicants fail to even request—much less justify—rule waivers that would be necessary to authorize their proposed SCS authorizations.”

Specifically, AT&T contends that the FCC’s rules do not permit SpaceX’s proposed use of T-Mobile’s broadband PCS G Block spectrum and this would require waiver of the US Table of Frequency Allocations (ToFA), Part 24 technical and operational rules, and the Commission’s own leasing rules.

The applicants – SpaceX and T-Mobile – have not met the waiver standard for the ToFA, the filing states, and “have failed to even request waiver of the relevant Part 24 and secondary market rules”.

The FCC should reject SpaceX’s request to simply take it at its word that it will not cause interference to other services, AT&T asserts.

But it’s OK, because the company has the answer to the problem. The best path forward for SCS, it claims in the filing, is a waiver-based approach that vests the Wireless Telecommunications Bureau (WTB) division of the FCC with sole authority to permit SCS operations in terrestrial mobile frequencies.

And just by chance, AT&T and satellite company AST SpaceMobile have submitted several forms to the WTB notifying it that they have entered into a spectrum manager leasing arrangement under which AT&T will “lease certain spectrum to AST for the provision of SCS services”.

In other words, AT&T has its own satellite service lined up via a partnership with AST SpaceMobile. The latter announced just last month that it had achieved what it claimed as the first ever two-way voice call by satellite connection using unmodified smartphones, in this case Samsung Galaxy S22 handsets.

It may appear that AT&T is taking an opportunistic swipe at a potential rival here, but Gartner VP Analyst Bill Ray told us AT&T’s concerns are legitimate, and the company is likely expressing annoyance that Starlink is not being asked to jump through the same hoops that SpaceMobile did in order to obtain authorization for a satellite service.

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“SpaceMobile’s point of differentiation is its huge antenna, which makes it capable of putting down a small spot beam which limits interference. Starlink’s v2 satellites have a tiny antenna, by comparison, which means bigger spot footprints and more potential for interference,” Ray said.

“That is the technical claim, and I think it has feet,” he added, “but we can’t know for certain until it’s too late. The value of SpaceMobile (with whom AT&T is working to provide comparable functionality) is in the small footprint, so if the FCC lets someone with bigger feet into the game then that devalues SpaceMobile,” he said.

We asked T-Mob and SpaceX for their reaction to this move by AT&T, but neither company had responded by the time of publication. ®