12.7 GHz Band Sees Conflicting Uses Pitched as FCC Considers Opening It to Satcom
Satellite operators are in a tug-of-war with terrestrial interests -- and at times with one another -- over the 12.7 GHz band, according to reply comments this week in docket 25-180. Initial comments in the proceeding also saw satellite industry interest in opening the 12.7 GHz band to satcom (see 2507290045). The FCC adopted a Further NPRM in May asking about opening the 12.7, 42 and 51.4-52.4 GHz bands, as well as parts of the W band, to satellite communications (see 2505280055).
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Pushing for allowing downlinks in the 12.7 GHz band, SpaceX said uplinks there "could provide value," but not as much as expanded downlink operations. FCC action on downlinks in the bands "would serve as a beacon for other administrations seeking to make similar upgrades to their allocation tables."
Reallocation of the 12.7-13.25 GHz band for non-geostationary orbit (NGSO) fixed satellite service (FSS) downlinks "is essential" for meeting the growing bandwidth demands of the satellite industry, the Commercial Space Federation said. The 12.7 band, alongside the Ku band, would create a contiguous downlink block from 10.7 to 13.25 GHz to support satellite broadband, the group said. In the name of global spectrum harmonization, it urged allowing earth stations in motion (ESIM) operations in the 12.2-12.7 GHz band.
A downlink allocation in 12.75-13.25 GHz wouldn't align with the international uplink allocation of this band and would raise interference concerns for passive services, said SES, Eutelsat, Hispasat and Ovzon. They said FSS uplinks in 12.75-13.25 GHz make sense, as such operations are internationally harmonized and already have satellite payloads in orbit, and there are existing equipment and customer ecosystems. Repacking the broadcast auxiliary service, cable relay service and fixed microwave operations in the 12.7 GHz band would quickly make it available for growing satellite needs and also harmonize that spectrum's use internationally, they said. The satellite operators also endorsed making the 42 and 52 GHz bands available for FSS and allowing geostationary orbit operations in the 52 GHz band, but not NGSO operations.
CTIA said the 12.7 GHz band is well-suited to be a relocation band for various services in the 1.3-10.5 GHz range. It said 12.7 GHz could handle sharing with federal FSS earth stations and with fixed-service users operating in other bands, thus helping free up midband spectrum. CTIA argued against blanket licensing in the 12.7 GHz band or allowing ESIM there, saying neither is compatible with ubiquitous terrestrial deployments.
WISPA called for spectrum in the 12.7 and 42 GHz bands to be made available for fixed wireless services on a primary basis or a co-primary, complementary basis with some fixed satellite services. With all the focus on making spectrum available for mobile and satellite needs, "potentially lost ... is the growing need for spectrum for terrestrial fixed wireless services." Making the 12.7 and 42 GHz bands available for such services would still leave the 52 GHz and W bands for satellite needs, as well as 800 MHz in the 12.7 and 42 GHz bands on a shared basis with terrestrial fixed wireless service, it said. The FCC doesn't need to keep looking at making the 12.7 or 42 GHz band available for terrestrial mobile wireless service, WISPA added, as no one in the proceeding is still seeking that access.
The Commercial Space Federation and SpaceX were critical of terrestrial operations in the lower and upper 12 GHz bands. CSF urged the FCC to close proceedings on allowing high-power terrestrial operations in the bands. Both said terrestrial operations would mean severe interference in the band and adjacent frequencies.
Other Bands
Disagreements weren't limited to 12 GHz spectrum.
The American Astronomical Society advised adopting ITU protection criteria for radio astronomy service for the 42.5-43.5 GHz RAS primary allocation that sits adjacent to the 40.5-42.5 GHz band. Logos Space Services said "the greenfield nature" of the 42 GHz band makes it ideal for allocating it on a primary basis for NGSO FSS operations. Pointing to concerns about interference to radio astronomy and passive services in neighboring bands, it said spectrum-sharing capabilities can mitigate in-band and adjacent-band interference.
It's clear that terrestrial operators don't have plans for the 42 or 52 GHz bands, said Amazon's Kuiper, while satellite operators "stand ready to put this fallow spectrum to productive use."
Arguments that the 50 GHz band is underutilized ignore that weather forecasting relies on passive data collected from the protected use of these bands, said weather interests, including the National Weather Association and the American Meteorological Society. An allocation for NGSO FSS unlinks that extends to 50.4-51.4 GHz could jeopardize temperature measurements done using 50.2-50.4 GHz, they said.
Moog said the FCC first needs a technical foundation that expanded satellite use can be introduced in the 90 GHz without substantial risks of harmful interference.