SpaceX and T-Mobile recently asked the FCC to provide a waiver regarding out-of-band emission limits for satellite-to-cellular service. Now, rival telecom and satellite companies are arguing that the Waiver Request from SpaceX would interfere with and degrade terrestrial cellular networks.
The Waiver Request submitted by SpaceX is fairly technical. Essentially, SpaceX wants a ninefold increase in the power flux-density (PFD) limits for out-of-band emissions—it wants to blast a stronger signal from its satellites. This will provide Starlink relays, which are currently being deployed for T-Mobile’s space-based cellular service, with the signal strength required for stable and reliable performance.
Rival companies that are pursing satellite-to-cellular or satellite broadband technology, including AT&T, Verizon, EchoStar, and Omnispace, argue that the FCC should deny SpaceX’s Waiver Request. In various forms, filings, and petitions, they say that the requested boost in Starlink emissions would harm Earth-based mobile operations. AT&T, which ran models to test SpaceX’s proposed PFD limits, suggests that we would see an 18% reduction in network downlink on cellular networks that use the PCS C Block (all three of the major U.S. telecoms use the C Block in some capacity).
“AT&T’s technical analysis shows that SpaceX’s proposal would cause an 18 percent average reduction in network downlink throughput in an operational and representative AT&T PCS C Block market deployment. Primary terrestrial licenses and networks must be protected from SCS interference, and operations under SpaceX’s Waiver Request would fail to do so.”
It should be noted that AT&T and Verizon’s satellite-to-cellular ambitions are hinged on AST SpaceMobile-designed BlueBird satellites. The BlueBird is equipped with a much larger antenna than SpaceX’s Starlink relay and may not require any changes to the FCC’s existing PFD limit.
Anyhow, SpaceX and T-Mobile anticipated this pushback. In an August 8th meeting with the FCC (filed on August 12th), the companies reviewed “robust technical submissions” to show that an adjusted PFD limit would not harm terrestrial cellular performance or increase the interference-to-noise ratio of domestic phone calls. T-Mobile also argued that, as a terrestrial carrier, it would not pursue a Waiver that could harm its own terrestrial operations.
And, notably, SpaceX warned the FCC that competitors would make a “last-minute attempt” to block the Waiver Request.
“Each time that SpaceX has demonstrated that it would not cause harmful interference to other operators—often based on those parties’ own claimed assumptions—those competitors have moved the goalposts or have claimed their analysis should not have been trusted in the first place. These operators’ shapeshifting arguments and demands should be seen for what they are: last-minute attempts to block a more advanced supplemental coverage partnership and siphon sensitive information to aid their own competing efforts.”
Remember, the above statement was made before AT&T and Verizon asked the FCC to deny SpaceX’s Waiver Request. SpaceX and T-Mobile have until August 22nd to submit a counterargument, and they’re expected to reiterate much of the information from their August 12th filing.
The corporate space race has been partially defined by nagging and infighting. When one company says “yes,” another will inevitably say “no.” If you hopped in a time machine and traveled back to the summer of 2023, you’d find AT&T and SpaceX arguing about interference, just as they are today. In some cases, the bickering is plainly justified, though disagreements related to science and engineering are difficult to parse.
Here’s the thing; we’re still trying to figure out how space-based internet and satellite service shouldwork. Even if AT&T and Verizon are intentionally trying to slow SpaceX’s ambitions, the concerns presented by these telecoms may contain a nugget of truth and should be evaluated. If nothing else, it’s an opportunity to learn more about satellite-to-cellular service and develop more effective guidelines for satellite deployment.
Source: FCC via The Verge
