AT&T & Verizon Challenge SpaceX-T-Mobile Direct-to-Cell Service Amid Interference Concerns

AT&T and Verizon have raised formal objections with the U.S. Federal Communications Commission (FCC) over SpaceX and T-Mobile's planned direct-to-cell satellite service, warning that the proposal could cause harmful interference to their terrestrial mobile broadband and PCS (Personal Communications Service) networks.

The SpaceX-T-Mobile partner arrangement aims to allow T-Mobile customers to connect to Starlink satellites wherever terrestrial coverage is weak or absent — including for users whose phones aren't satellite-enabled. This fall, SpaceX expects to have approximately 800 satellites capable of direct-to-cell connectivity. The goal is to eliminate outdoor dead zones and bolster nationwide coverage.

However, AT&T claims in its FCC filing that SpaceX's request to relax limits on out-of-band emissions, supplemental coverage from space (SCS), and power flux density (PFD) would degrade AT&T's network performance. Specifically, AT&T's analysis projects an 18% average throughput reduction in downlink speed in certain PCS C-Block markets if the waiver is granted. They argue that interference from satellite emissions adjacent to their licensed spectrum undermines mobile service quality and violates regulatory protections afforded to terrestrial licensees.

Verizon echoes those concerns, arguing that the proposed direct-to-cell operations could "undermine the Commission's core goal of protecting incumbent terrestrial licensee operations from SCS satellite operations in adjacent bands." Their filing warns that the interference risk threatens existing mobile broadband coverage, spectrum integrity, and user experience.

SpaceX and T-Mobile respond that the direct-to-cell design will not cause harmful interference. T-Mobile reiterated confidence that operations in the relevant frequency bands (including the PCS G block) can be configured to avoid adverse effects on terrestrial operations. They maintain that the proposed technical safeguards will respect emission limits and mitigate out-of-band spillover.

In the round of regulatory back-and-forth, both AT&T and Verizon are also exploring satellite partnerships themselves. They are working with AST SpaceMobile to deliver satellite connectivity using standard smartphones — underscoring how satellite-enabled mobile connectivity is shaping up as a major battleground for coverage expansion.

With public comment deadlines approaching, the FCC will have to weigh spectrum management, interference risk, service quality for mobile broadband, and consumer coverage benefits. The outcome could reshape rules around satellite-to-cell licensing, out-of-band emission limits, and the future of mobile-satellite service integration in the U.S.