SpaceX Gets Pushback Against SCS PFD Changes Proposal

SpaceX is facing opposition from wireless and satellite entities over its requested waiver that would allow relaxed out-of-band power flux density limits for the company's proposed supplemental coverage from space service, according to docket 23-135 filings Tuesday. In its June waiver request, SpaceX said its proposed PFD limits would protect adjacent band networks from interference while avoiding too-restrictive limits. Separately, Omnispace petitioned the FCC, urging denial of SpaceX's pending request to add the 340-360 kilometer altitude shells as a deployment option for its SCS service (see 2406210006).

AT&T said its technical analysis points to SpaceX's PFD proposal causing an 18% average reduction in network downlink throughput to an AT&T PCS C Block market deployment. In its petition to deny, AT&T said SpaceX's analysis "rests on unsound assumptions." SpaceX has not shown that its proposed ninefold increase to the SCS out-of-band PFD limit won't cause harmful interference to terrestrial mobile incumbents, it added.

SpaceX has admitted it can't comply with the PFD limit, and now seeks to eliminate the rule, EchoStar said in its petition to deny. "This collateral attack on a rule is not what waivers are for."

The SpaceX-sought relaxed limits would mean harmful interference for incumbent primary terrestrial operations in adjacent bands, Verizon said. It said FCC limits on SCS systems for aggregate out-of-band space downlink emissions were to protect adjacent band operations, and SpaceX’s proposal would undermine that goal.

Pointing to its licenses in the PCS G Block and adjacent PCS C Block, T-Mobile said it has a "strong incentive and ... obligation" to ensure out-of-band emissions don't cause harmful interference to its own or others' operations. In a filing recapping a meeting with FCC Wireless and Space Bureau staffers, T-Mobile said its review of SpaceX's waiver request gave it "confidence" that proposed PCS G Block operations wouldn't cause interference to adjacent-band terrestrial operations, including T-Mobile’s own adjacent-band operations. T-Mobile and SpaceX said they warned the agency that competitors would make "last-minute attempts to block a more advanced supplemental coverage partnership and siphon sensitive information to aid their own competing efforts."

Citing its previous arguments that allowing non-conforming SpaceX SCS downlinks in primary mobile satellite service uplink spectrum would cause interference with its satellites, Omnispace said in its petition that adding lower altitudes doesn't fix its interference concerns. Omnispace is fine with SpaceX operating in the 340-360 km orbital shells using spectrum the FCC authorized for SpaceX. But the agency should reject the requested use of the 1990-1995 MHz band, including at the 340-360 km altitudes, Omnispace said. That proposed use "is simply incompatible" with primary MSS systems that other administrations licensed, it said.