A big piece of what the FCC does is to weigh competing claims to use spectrum. It seems like there have been non-stop industry fights over the last decade on who gets to use various bands of spectrum. One of the latest fights, which is the continuation of a battle going on since 2018, is for the use of the 12 GHz spectrum.

The big wrestling match is between Starlink’s desire to use the spectrum to communicate with its low-orbit satellites and cellular carriers and WISPs who want to use the spectrum for rural broadband. Starlink uses this spectrum to connect its ground-based terminals to satellites. Wireless carriers argue that the spectrum should also be shared to enhance rural broadband networks.

The 12 GHz band is attractive to Starlink because it contains 500 MHz of contiguous spectrum with 100 MHz channels—a big data pipe for reaching between satellites and earth. The spectrum is attractive to wireless ISPs for these same reasons, along with other characteristics. The 12 GHz spectrum will carry twice as far as the other spectrum in point-to-multipoint broadband networks, meaning it can cover four times the area from a given tower. The spectrum is also clear of any federal or military encumbrance—something that restricts other spectrum like CBRS. The spectrum is also being used internationally for cellular purposes, making it easy to find the radios and receivers to use it.

In the current fight, Starlink wants exclusive use of the spectrum, while wireless carriers say that both sides can share the spectrum without much interference. These are always the hardest fights for the FCC to figure out because most of the facts presented by both sides are largely theoretical. The only true way to find out about interference is in real-world situations—something that is hard to simulate any other way,

A few wireless ISPs are already using the 12 GHz spectrum. One is Starry, which has recently joined the 12 GHz Coalition, the group lobbying for terrestrial use of the spectrum. This coalition also includes other members like Dish Networks, various WISPs, and the consumer group Public Knowledge. Starry is one of the few wireless ISPs currently using millimeter-wave spectrum for broadband. The company added almost 10,000 customers to its wireless networks in the second quarter and is poised to grow a lot faster. If the FCC opens the 12 GHz spectrum to all terrestrial uses, it seems likely that use of the spectrum would quickly be used in many rural areas.

As seems usual these days, both sides in the spectrum fight say that the other side is wrong about everything they are saying to the FCC. This must drive the engineers at the FCC crazy since they have to wade through the claims made by both sides to get to the truth. The 12 GHz Coalition has engineering studies that show that the spectrum could coexist with satellite usage with a 99.85% assurance of no interference. Starlink, of course, says that engineering study is flawed and that there will be significant interference. Starlink wants no terrestrial use of the spectrum.

On the flip side, the terrestrial ISPs say that the spectrum in dispute is only 3% of the spectrum portfolio available to Starlink, and the company has plenty of bandwidth and is being greedy.

I expect that the real story is somewhere in between the stories told by both sides. It’s these arguments that make me appreciate the FCC technical staff. It seems every spectrum fight has two totally different stories defending why each side should be the one to win use of spectrum.