Trump's 'Golden Dome' Could Add to Spectrum Crunch: National Spectrum Consortium

President Donald Trump has pushed for a U.S. missile defense system based on Israel’s “Iron Dome,” which has intercepted thousands of rockets, with a 90% success rate, during Israeli conflicts with Iran and Hamas.

“I’m not sure, based on the conversations we’ve had both with the government and industry, that anybody has defined well enough what the Golden Dome will be or what it will accomplish in the near to medium term,” Kochan said. The administration appears to want to launch a system in the next two to three years, he said, which is “a wildly ambitious goal.”

Deploying a missile defense that quickly would likely require using many existing systems and technologies rather than developing new ones, Kochan said. A lot of those defense systems have been deployed outside the continental U.S. but not domestically, he noted. If such systems are used here, “the spectrum issue is going to bubble up to the surface a lot more quickly than people are calculating” because some of the bands that would be used would no longer be available for auction to meet the aggressive targets of the 800 MHz spectrum pipeline.

“I’m not sure anybody has really, truly thought through exactly how difficult the spectrum question is going to get and how fast that’s going to come.”

He added that the bands most likely to be used include the 3 and 4 GHz bands, which already contain a number of military radars, and 7 and 8 GHz. A paper that the consortium released in April cites as a possibility the Aegis Combat System used by Navy destroyers.

Kochan also highlighted the plan's challenges in an opinion piece this week in Defense Daily. “The proposed Golden Dome isn’t just a new missile defense system; it’s a massive feat of engineering,” he wrote. “Building it will require integrating radars, satellites, and missile interceptors into a complex network of systems at a scale not seen before.” The network must also “operate in an already congested electromagnetic spectrum, or it risks catastrophic failure.”

Upper C Band

Mari Silbey, the consortium's chief program officer, said air safety questions in the upper C band and protection for radar altimeters remain an issue as the FCC looks to auction at least 100 MHz of midband spectrum, as required by federal legislation (see 2509120049). A number of wireless researchers have tried to get access to part of the band, “just to do technical research … sometimes only indoors and at low power,” Silbey said. “It has been virtually off the table.”

The response the researchers got was “we want to protect everything in the aircraft,” even if it's probable that there’s no risk, Silbey said. Building trust with the airline industry and coming to an agreement on sufficient guardrails to protect altimeters “is still a major hurdle.”

DOD was traditionally leery of sharing spectrum, Kochan said. “They heard that as you’re taking something away,” he said. But the thinking within DOD “has come around significantly, pretty much across the board.” The biggest challenge remains “trust and faith."

Demonstrations and prototyping are critical to building that trust, Kochan added. In the past, as conversations unfolded, the DOD would come in with a radio access model and interference prediction based on using 5G adjacent to a military system, he said. Industry representatives would ask about the data used in the model and say “that has nothing to do with how we’re operating our network,” he said. “There was such a disconnect.”

“You’re not going to fix that” with more modeling and another interference study, Kochan argued, because it's critical to test systems in the real world and prove to the DOD that commercial and military systems can coexist. “The answer is: Here is a dual-use system,” he said. “Here we’ve taken a system that can be used both to sense and communicate and [to] build a new capability for DOD.”

“We talk about spectrum sharing as if DOD only builds radar and industry only builds wireless networks,” Kochan said. But consumers are using sensing devices in their daily lives, and “DOD needs to communicate -- folks in uniform carry iPhones.” There needs to be a move away from “large fixed locations for sensitive systems that cannot possibly get anywhere near anything else” without failing, he said. “That’s not the reality, and we need to show people that.”

Using models “was completely fine when you had lots of cushion” and lots of guardrails, Silbey said, but spectrum today is too congested to continue to rely on models.