Spectrum allocation is a very complicated game. It must balance the rights and priorities of many stakeholders, including the DoD and other federal spectrum users, commercial wireless players, new NGSO systems and legacy GSO satellites. And with the FCC potentially altering long-established patterns of spectrum allocation, and a dynamic sharing mechanism scheduled to be demonstrated in November, there’s no telling where the pieces will fall. Who comes out on top: the FCC’s Space Bureau? Wireless? SpaceX? Legacy GEO, which has managed to hold onto its precious bandwidths for decades?
For the past several months, the FCC—led by new head of the Space Bureau, Jay Schwarz—has made a concerted effort to streamline and reform satellite licensing processes. It has also announced the intention to open several new sections of bandwidth, including a proposal to open up the lower 37 GHz band, and adopted new sharing rules on the 37 band to encourage wireless innovation. In May, the FCC also proposed a rulemaking that would unleash spectrum across twelve additional bands, including the 12, 42 and 51 GHz bands.
NGSO-GSO Sharing Rules Go Under Review
In August 2024, SpaceX filed a petition to update the NGSO-GSO spectrum-sharing regime, arguing that the current system is inefficient and NGSO operators should not be required to follow dated technical rules that were developed for the 1990s satellite market. The FCC’s Space Bureau has expressed interest in addressing this issue, most recently with the announcement into an inquiry on expanding the spectrum sharing capabilities between GSO and NGSO systems, which have historically required NGSO operators to observe strict EPFD power limits.
As NGSO systems have grown larger and more complex, spectrum rules are now being re-examined.
The existing regulatory framework is designed to protect GSOs, which have less flexibility than NGSO systems. But as NGSO systems have grown larger and more complex, these rules are now being re-examined. In the announcement, the FCC stated that it is looking “to update those power restrictions for the workhouse satellite frequencies (Ku- and Ka-bands) that support the next generation of satellite broadband constellations in low-Earth orbit.”
As the satellite industry has grown over the last few decades, and especially as NGSO systems demand more and more bandwidth, the balance of spectrum use has begun to shift—occasionally leading to tension between operators as new spectrum is opened or as legacy players hold onto widely sought-after spectrum.
Wireless and NGSO Vie for the C-band
While NGSO players like Starlink want more spectrum access and to lift EPFD limits on spectrum shared with GSO satellites, they are also wading into a fight with wireless. In February, the FCC announced the intention to repurpose lower C-band frequencies for more intensive use.
CTIA, the wireless industry association, emphasized the benefits of freeing up and efficiently using the mid-band spectrum for 5G. “The U.S. wireless industry is facing a growing spectrum shortfall as demand for mobile data accelerates,” said a representative of CTIA in a statement to Constellations. “Unlocking additional mid-band spectrum, particularly in the upper C-band, is a critical step to restoring America’s 5G leadership, protecting our national security and laying the groundwork for 6G.”
“Unlocking additional mid-band spectrum, particularly in the upper C-band, is a critical step to restoring America’s 5G leadership, protecting our national security and laying the groundwork for 6G.” -CTIA representative
While the wireless industry celebrated the move, SpaceX quickly took action by sending a letter to the FCC asking it to allow multiple providers to share the spectrum, rather than handing the band over for exclusive use by wireless for 5G systems.
And more major changes lie ahead. In May, the Space Bureau announced that it would begin examining EchoStar’s use of the 2 GHz band for mobile-satellite service (MSS). Two days later, SpaceX applied for access to the 2 GHz band for Starlink broadband. A similar request was made and denied a year ago.
In 2023, the FCC announced a new regulatory framework known as supplemental coverage from space (SCS). This framework, “the first of its kind in the world,” according to the FCC, allows satellite operators that provide direct-to-device services to use mobile spectrum, provided that they obtain an agreement from the mobile operator.
Convergence, Competition and Cooperation
Despite these competing interests, cooperation will be key to ensuring secure access to spectrum across the board. “The relationship between satellite and terrestrial operators will continue to be both cooperative and competitive,” said Mari Silbey, chief program officer at the National Spectrum Consortium (NSC).
“The relationship between satellite and terrestrial operators will continue to be both cooperative and competitive.” -Mari Silbey, NSC
On the other hand, tension can sometimes arise between competing entities. “It would be natural for satellite and terrestrial operators to be wary of each other on the issue of spectrum, particularly when access is granted via exclusive licenses,” Silbey said.
With spectrum demand continuing to grow, there is a growing case for alternative models of licensing and access, such as the SCS model. The current dominant model of exclusive licensing restrains innovation that would move the industry in the direction of spectrum-sharing. But this can be difficult, because “from a regulatory perspective… incentives are not well aligned for spectrum sharing,” Silbey said.
As technology develops, policy may have to be rewritten to take spectrum-sharing into account, especially as “it becomes possible to allocate spectrum dynamically, meaning multiple users could operate in the same spectrum bands,” Silbey said.
Dynamic Spectrum Sharing Could Change the Nature of the Game
“There will always be demand for more wireless spectrum,” Silbey said. “The question we should be reckoning with is not whether we can move incumbents from specific frequencies to accommodate commercial 5G demand, but how we can use spectrum more efficiently. We should be focusing on the technology innovations that will enable spectrum coexistence and spectrum-sharing.”
Efforts to introduce spectrum sharing technologies into the industry have been made several times. Notably, the FCC created the Citizens Broadband Radio Service (CBRS) in 2015, which manages 150 MHz of spectrum on the 3.5 GHz band via three tiers of access, allowing federal and non-federal users to share the band. But CBRS isn’t a truly dynamic sharing system; it can take minutes, hours or even days for a user to receive approval to access the band.
Dynamic spectrum sharing (DSS) mechanisms have been a topic of study for several decades now, and an upcoming demonstration by the Pentagon’s FutureG office could mean that large-scale, multi-domain, truly dynamic spectrum-sharing will soon be a reality for the industry. In the next few years, the 3.1-3.45 GHz S-band could be dynamically shared between military and commercial players.
“It’s a question of balancing those degrees of freedom, and of each individual user’s desire for the capacity that they want to be able to utilize.” -Thomas Rondeau, Office of the Under Secretary of Defense for Research and Engineering
DSS balances the needs of several players at once by ranking the degree of security and capacity needed by each user, and dynamically allocating spectrum to them as needed. “It’s a question of balancing those degrees of freedom, and of each individual user’s desire for the capacity that they want to be able to utilize,” said Thomas Rondeau, principal director for FutureG at the Office of the Under Secretary of Defense for Research and Engineering. “Basically, it’s a very complicated scheduling problem.”
DSS is All About the Details
For a problem like this, with multiple players seeking access to the same resource using vastly different technologies, things get complicated quickly. “The devil is in the details,” Silbey said. “Complicating factors include how legacy systems operate, how new systems are built and how well operators are willing to work together.”
Once an effective sharing mechanism is in place, multiple players could access the same spectrum in quick succession.
“If somebody is using it, as soon as they get off that frequency or off of that spectrum band, someone else can jump in and take it,” said Joshua Weaver, director of spectrum initiatives and analysis at the Office of the Under Secretary of Defense for Research and Engineering. “That’s the whole point. DSS decreases those timelines and increases the amount of sharing that we can do and the amount of spectrum we can access, both for national security purposes and for economic exploration.”
“DSS decreases those timelines and increases the amount of sharing that we can do and the amount of spectrum we can access, both for national security purposes and for economic exploration.” -Joshua Weaver, Office of the Under Secretary of Defense for Research and Engineering
A truly dynamic system cannot be managed by a human operator, where decisions about access can be made and modified moment-by-moment. “These are really hard problems to solve, especially if you’re trying to do it in real time, and dynamically with live systems,” Rondeau said. “Obviously, these days, we’re looking more towards AI and ML type algorithms to help us with these.”
The US Leads in Spectrum-Sharing—For Now
The investment could be well worth it; wide use of DSS would give the US an edge on the international stage. “I don’t have awareness of anyone that’s actually doing spectrum sharing, other than the US,” Rondeau said. “We are the global leader in spectrum policy.”
To keep this lead, the US will need to not only prove the technology but also build trust among operators. “The US needs to invest in a comprehensive, long-term research and prototyping program to understand the full breadth of spectrum-sharing options, and to build trust that spectrum sharing can be successful in large-scale deployments,” Silbey said.
While the US maintains the lead in this area, China is researching and implementing some interesting approaches to spectrum use. One example is an underlay model, which layers local 5G WiFi systems on top of military systems on the lower 3 GHz. This model works because WiFi systems are limited to small-scale indoor use for a relatively small market. Because of the limited scale, spectrum can be used simultaneously with the military systems without significant interference.
“On the technology side, the hurdle really is around funding, research and demonstrations that prove the technology is viable, reliable and can be iterated upon,” Silbey said. Perhaps that proof will be provided in November’s DSS demonstration, or in a fully comprehensive demonstration that is currently scheduled for summer 2026.
If spectrum sharing becomes a technologically viable approach to spectrum allocation, industry dynamics could change significantly.
If spectrum sharing becomes a technologically viable approach to spectrum allocation, industry dynamics—between satellite and wireless, between NGSO and GSO, between commercial and military—could change significantly. What is now considered a quickly dwindling resource may soon be massively more available. Or, as Weaver put it: “spectrum is a situationally finite resource, but an infinitely renewable resource.”
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