One of the most difficult aspects of writing about the wireless industry is understanding the use of spectrum. But if I thought that was hard, I’ve been blown away by how complicated it is to understand the spectrum landscape in the satellite industry.
At first, I thought it was just me. I must not be smart enough to easily grasp this stuff. After all, I have a degree in journalism, not rocket science.
But then, I wrote a report for Fierce Network Research, “Satcoms + telecom: A match made in the heavens.” I talked to a number of people for this report, and I was surprised that many of them couldn’t answer my questions about spectrum. They would tell me that they covered GEO, but didn’t know much about the use of spectrum for LEO. Or others would tell me they were on the business side of the house, not the in-the-weeds technology side of the house.
Ok. Fair enough. But that’s different than the terrestrial wireless industry where almost everyone I interview has a basic grasp on spectrum.
Recently, I wrote a story summarizing the current collaborations between satellite operators and telecom companies, and I wanted to include a little information about spectrum. I first checked ChatGPT, and it provided some information that seemed reasonable. But to confirm the information I reached out to Michael Calabrese, director of the Wireless Future Program at the Open Technology Institute at New America, which just published a satellite report.
Sadly, much of the ChatGPT information was wrong (which makes me worried about the trillions of dollars we’re investing in AI and which we're banking our economy on. But that’s a topic for a different day).
Calabrese talked to me from the Americas Spectrum Management conference in Washington, D.C., last week. In terms of the complexity surrounding satellite spectrum, he said, “It’s really funny because we almost think of ourselves as some kind of secret society or something, because so few people can wrap their heads around it.
There's something about it that's just really difficult to completely understand.”
Satellite spectrum for dummies
The New America report is an excellent primer for those of us trying to understand satellite spectrum. First, it’s important to note that the spectrum used for fixed satellite service (FSS), such as SpaceX’s Starlink broadband, is different than the spectrum used for mobile satellite service (MSS), which is necessary for direct-to-device services.
The below two charts are particularly useful.
The wide higher-frequency FSS bands are shared internationally, although they were not originally planned with large-scale LEO constellations in mind. Conversely, the narrow low-frequency MSS bands are assigned to single operators.
The three primary MSS bands are much lower in frequency than FSS spectrum and thus better able to connect to consumer handsets. Calabrese said the key thing about MSS spectrum is that it needs to be low-band because cell phones don’t have much power, so there must be enough propagation for the return path of the signal up to the satellite.
Neither the International Telecommunication Union (ITU) nor the Federal Communications Commission (FCC) currently uses an auction system for MSS or FSS spectrum. The ITU lacks the authority to hold a global auction and requires operators to obtain a license from their national regulator, as well as an authorization for market access in any nation where they operate.
Calabrese said, “All satellite spectrum is allocated by the ITU, you know, globally for harmonization. And then it's up to each country to decide who either gets a license or has market access in that country.”
This short summary really is “satellite spectrum for dummies,” because there are so many factors involved. These include regulatory regimes, competitive dynamics and spectrum-sharing protocols, not to mention technological challenges.
I would encourage you to read the New America report for all the details (106 pages).
Although it seems like it, satellite spectrum is not really a secret society. It’s just very complicated.
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