There’s a lot of interest in the 3.7-4.2 GHz band—it’s the subject of an Order and Notice of Proposed Rulemaking (NPRM) at the FCC—and a lot of folks want to see more accurate databases of where satellite earth stations are located in order to get a better picture of what’s going on in the band.
The 3.7-4.2 GHz band, also referred to as the C-Band, is heavily used by the satellite community for satellite downlinks to distribute programming content for the likes of TV and radio broadcasts, live sports events and cable TV. It’s also viewed as prime real estate for 5G.
One of the problems has been that the FCC database was sorely inadequate and didn’t show a true reflection of where the incumbents’ earth stations were located. So the FCC set a 90-day window for companies to register their earth stations in order to develop a better record.
ComSearch, a CommScope company, has been tracking that data and mapped the newly registered earth stations. As of July 26, there were over 1,300 newly registered earth stations—in addition to over 4,000 existing sites, according to Laura Fontaine, director of Products at Comsearch.
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The FCC is considering a verification process to confirm locations and other operating parameters in its recent NPRM. (The original window closing date of July 18 was extended to Oct. 17, and additional registrations are expected up until that date.)
Registration not only protects the incumbent earth stations but makes them eligible for potential compensation from new mobile entrants that are eyeing the spectrum for 5G.
The map above (here is a bigger version of this image) represents what is currently in the FCC database, before and after the beginning of the freeze window.
“Most of these earth stations were not previously registered,” Fontaine explained via email. “The FCC typically only requires registration or licensing of transmitters.”
These earth stations only receive downlink data from the satellite in this band. C-Band earth stations transmit in the 6 GHz uplink band, which is another area of interest at the FCC. Commissioner Michael O’Rielly previously has said he would like to see the 3.7-4.2 GHz band paired with the 6 GHz band, but so far they are separate items.
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Knowing these locations will help the FCC understand the potential impact from new entrants, but this is just one aspect to provide a complete picture, Fontaine said. The data requested by the FCC in the NPRM (e.g. azimuth and elevation gain pattern, transponder numbers, etc.) will provide a better understanding of overall spectrum usage.
Comsearch is a provider of spectrum sharing services, implementing satellite and terrestrial sharing through frequency coordination, so it has a stake in how things shake out. It also supports other types of sharing, including developing Spectrum Access System (SAS) and Environmental Sensing Capability (ESC) operations in the 3.5 GHz Citizens Broadband Radio Service (CBRS) band.