The 12 GHz Battle

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 fight 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 also is being used for cellular purposes internationally, which makes for an easy path 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.

The Fight Over 12 GHz Spectrum

For an agency that has tried to wash its hands from regulating broadband, the FCC finds itself again trying to decide an issue that is all about broadband. There is a heavyweight battle going on at the FCC over how to use 12 GHz spectrum, and while this may seem like a spectrum issue, it’s all about broadband.

12 GHz spectrum is key to several broadband technologies. First, this is the spectrum that is best suited for transmitting data between the earth and satellite constellations. The only way Starlink is going to be able to grow to serve millions of remote customers in the U.S. is by having enough backhaul to fuel the huge amounts of data that will be passed to serve that many customers. Lack of backhaul bandwidth will significantly limit the total number of customers that can be served and is an obvious major concern of the satellite companies.

It turns out that 12 GHz is also the best spectrum for transmitting large amounts of data with 5G. The carriers have been dabbling with the higher millimeter-wave spectrum, but it’s turning out that there are squirrelly aspects of millimeter-wave spectrum that make it less than ideal in real-world wireless deployments. The 12 GHz spectrum might be the best hope for carriers to be able to deliver gigabit+ wireless drops to homes. Verizon has been deploying fiber-to-the-curb technology using mid-range spectrum and seeing speeds in the range of 300 Mbps. Using the 12 GHz spectrum could provide a reliable path to multi-gigabit wireless drops.

The big question facing the FCC is if 12 GHz can somehow be used to satisfy both needs, pitting the 5G carriers against the satellite carriers. As an aside, before talking more about the issue, I must observe that the satellite companies bring a new tone into FCC proceedings. Their FCC filings do everything except call the other side a bunch of dirty scoundrels. Probably only those who read a lot of FCC documents would notice this, but it’s something new and refreshing.

The current argument before the FCC comes from filings between Starlink and RS Access, which is associated with Michael Dell, who owns a lot of the spectrum in question. But this is part of the larger ongoing battle, and there have been skirmishes that also involved Dish Networks, which is the largest owner of this spectrum.

The FCC will have to somehow untie the Gordian knot on a tough issue. As is to be expected with any use of spectrum, interference is always a major concern. The usefulness of any band of spectrum can be negated by interference, so carriers only want to deploy wireless technologies that have minimal and controllable interference issues. Both sides in the 12 GHz fight have trotted out wireless engineers who support their positions. RS Access says that spectrum can be shared between satellite and terrestrial usage, supporting the idea of not giving more spectrum solely to Starlink. Starlink says the RS Access engineers are lying and wants dedicated spectrum for satellite backhaul. I don’t know how the FCC can sort this out because the only way to really know if spectrum can be shared is to try it.

What I find most unusual about the fight is that the FCC is being dragged into a broadband issue. The last FCC Commission, Ajit Pai, did his best to wash broadband out of the vocabulary at the FCC. But in today’s world, almost everything the FCC does, other than perhaps chasing robocallers, is ultimately about broadband. While this current 12 GHz fight might look like a spectrum battle to an outsider, it’s all about broadband.