Starlink's rivals in the satellite phone service race are asking the Federal Communications Commission (FCC) to reject its request for a waiver relating to out-of-band emission limits on signals, claiming this would cause interference with terrestrial cell networks.

The SpaceX subsidiary has plans to deliver a "direct-to-cell" satellite comms service with T-Mobile US, which would allow subscribers across the US to make calls using a satellite link in areas where there is no coverage from cellphone towers.

However, the other two of America's big three cell network operators, Verizon and AT&T, have teamed up with a different satellite provider - AST SpaceMobile - to allow their own users to make calls in areas with no cell tower coverage.

Now Verizon and AT&T have both submitted documents to the FCC asking it to deny a SpaceX request for a waiver relating to out-of-band emission limits on signals, which the Musk-run biz says it needs for Starlink satellites to operate the service, or "supplemental coverage from space" (SCS), as it is referred to in the documents.

The two telcos contend that this waiver would allow Starlink to operate satellite services using a signal strength that would risk interference with existing cellphone services.

Verizon states in its petition [PDF] that SpaceX filed an application to add an SCS payload to its second generation satellites in early 2023, and had at that time requested a waiver of the FCC's limits applicable for terrestrial operations.

The Commission subsequently adopted new rules governing SCS operations, including imposing an aggregate out-of-band power flux-density (PFD) limit of -120 dBW/m²/MHz on SCS operations.

SpaceX subsequently filed a supplemental waiver request in its SCS application seeking to operate its SCS satellite system with an out-of-band PFD limit of -110.6 dBW/m²/MHz, arguing that the Commission's limit was "wrongly decided" and would not be practically achievable by SpaceX on an aggregate basis, Verizon states.

In other words, SpaceX says it can't operate the planned service unless it is allowed to go outside the restrictions put in place by the FCC to prevent interference with other services.

AT&T claims in a filing [PDF] that SpaceX's proposed aggregate PFD limit is nearly nine times less stringent than the limit specified by the Commission in its SCS Order, which would be "insufficient to protect terrestrial wireless services and is based on inappropriate theoretical analysis."

This isn't a new tactic from AT&T; the telco filed a similar petition to the FCC in May last year asking it to block the proposed Starlink service because the signals beamed from space could interfere with terrestrial cellphone services it operates in adjacent frequency bands.

A cynic might say that this is quite a convenient way for AT&T and Verizon to nobble a potential competitor to their own plans for SCS services, but it also appears their concerns have some validity.

"The issue is that no one has ever done this before, so no one knows how bad (or how benign) [interference] might be," Gartner Distinguished VP Analyst Bill Ray told The Register.

"There are legitimate concerns, but what we're seeing, across the industry, is attempts to use regulators to frustrate competitors. I wish I could say that it's one side doing this. Unfortunately, it seems an essential part of the process," he added.

The FCC and AT&T refused to comment. We are awaiting a response from SpaceX and Verizon.

AST SpaceMobile, the satellite operator that Verizon and AT&T have cozied up to, has designed its BlueBird satellites with massive antennas. This should allow them to put down a small spot beam that limits interference, as Ray has previously explained, but he added the proviso that the spectrum Starlink is using with T-Mobile uses higher frequencies, so wouldn't need such a large antenna.

AST confirmed in a Business Update this week that the first five of those commercial BlueBird satellites are scheduled for launch in the first half of September, ironically on a SpaceX Falcon 9 rocket. ®

https://www.theregister.com//2024/08/16/att_verizon_starlink/