President Biden unveiled his first budget proposal to Congress Friday, outlining $1.52 trillion in spending recommendations for the government's fiscal 2022 year. And the president suggested allocating a tiny portion of that sum for technology meant to increase the amount of spectrum available to 5G operators.

But, perhaps not surprisingly, there are strings attached.

Specifically, the White House requested $39 million in 2022 "for advanced communications research at the National Telecommunications and Information Administration (NTIA), which would support the development and deployment of broadband and 5G technologies by identifying innovative approaches to spectrum sharing."

Those spectrum sharing comments are likely a reference to IIC (Incumbent Informing Capability) technology.

The NTIA hinted at the possibilities of IIC in a research paper last year: "NTIA will examine the development of an automated, real-time, incumbent-informing spectrum sharing system (incumbent-informing system) that NTIA would operate in conjunction with DoD [Department of Defense] to notify commercial entities when the latter would need to cease operations."

Thus, IIC technology would allow US military commanders to tell operators like AT&T and Verizon when they can – and can't – use government spectrum for 5G.

It would also represent a significant upgrade to the Environmental Sensing Capability (ESC) technology that's currently employed for spectrum sharing in the 3.5GHz CBRS band. While that technology is working, some vendors have complained that ESC is causing "spectrum waste."

The debate is important because IIC could ultimately dictate how commercial companies like AT&T and military users like the US Navy use the entire 3GHz band, which comprises fully 1GHz (or 1,000MHz) of midband spectrum. That's more midband spectrum than any country has allocated for 5G, anywhere in the world.

The DoD, for its part, has set its sights squarely on sharing its spectrum rather than allocating it exclusively for 5G, as T-Mobile and others want. "The traditional model of static frequency allocation is not sufficient, and a new model is needed," the DoD wrote about its new spectrum strategy. "Spectrum sharing offers a new model for greater freedom of action."

A new standard for spectrum allocation

Likely as a result, the noise around spectrum sharing and IIC is growing. Specifically, the NTIA released a report in February on the possibilities surrounding IIC, and what the technology might do.

"The NTIA vision for IIC is that it evolves to become a 'uniform standardized platform' for spectrum sharing across multiple bands," the agency wrote in the report. "NTIA expects that IIC will be deployed over the next few years to support midband spectrum sharing predominately between federal systems and broadband wireless carriers using 4G and 5G technology. NTIA anticipates that IIC will evolve to become a federalized system run and administered by NTIA. IIC is expected to be a long-term project with iterations that will ultimately allow federal agencies to populate and update in realtime a database with frequency, location, and time-of-use information for systems they deploy in the US."

The agency – which is responsible for advising the president on telecommunications and information policy issues – said that it first wants to deploy IIC in the CBRS band across roughly a dozen test locations. If that effort is successful, it would then evaluate expanding IIC functionality to other midband spectrum – and potentially "all federal operations in other bands."

NTIA's view of the technology is expansive: "IIC could permit easier and quicker spectrum access for commercial wireless services and open the door to innovative, real-time automation. Moving complex federal systems to different spectrum bands has been laborious, time-consuming, and expensive – and eventually there will be no place left to move. The IIC, however, could securely and reliably expedit spectrum repurposing, demonstrating that innovation can continue to solve difficult spectrum challenges."

Interestingly, the agency also hinted that IIC could ultimately leverage artificial intelligence (AI) technology that is currently being developed by the Pentagon's Defense Advanced Research Projects Agency (DARPA).

However, IIC clearly isn't ready for prime time just yet. Last year there were lengthy discussions about whether the FCC should use IIC technology to share spectrum in the 3.45–3.55GHz spectrum band it plans to auction in October. The FCC decided not to do that, but it left the door open to using IIC in the band at some point in the future: "An Incumbent Informing Capability (IIC) also could be developed to facilitate coordination," the agency wrote in its March proposal for 3.45-3.55GHz auction rules.

A debate for exclusive spectrum use

Perhaps not surprisingly, a number of 5G providers aren't thrilled at the prospect of sharing their spectrum licenses with soldiers and others.

"This approach is ineffective for the shared use of spectrum between federal operations and commercial terrestrial wireless operations and should be rejected," T-Mobile wrote to the FCC of the NTIA's IIC proposal.

"IIC also poses some inherent problems," analyst Peter Rysavy, president of Rysavy Research, wrote recently. "For example, military incumbents, not wishing to advertise their movements, might obfuscate their operations by retaining more spectrum over larger areas than they actually need."

But the notion of spectrum sharing appears to have been embraced across the Biden administration. "It is my hope that our future efforts to find more spectrum for 5G will enjoy the flexibility to explore every option available to us, including the opportunity to pursue more innovative spectrum sharing policies like we have in the CBRS band," wrote FCC Acting Chairwoman Jessica Rosenworcel in a recent statement.

Others agree.

"We should explore spectrum sharing and other auction alternatives," wrote former Google boss Eric Schmidt in recent Congressional testimony. "For example, DoD has invited public input into how it could share spectrum it controls with industry. I have suggested a model wherein DoD retains control of the spectrum but allows industry to share it in exchange for industry building the required infrastructure quickly, and at its own cost. To be clear, this is not 'nationalized 5G,' as some critics have claimed. This would be a privately built, operated and maintained network that prioritizes DoD use. In any case, I believe DoD should be applauded for examining innovative solutions to this urgent problem."

During that same Congressional hearing, Microsoft's Brad Smith said there are two models for sharing 3GHz spectrum: One is for DoD to own it and lease it, another is to auction it and make sure DoD has priority access to it. He said there needs to be a discussion about which is best.

It's unclear whether Congress will pass Biden's budget proposal. But if the NTIA does get that $39 million for spectrum sharing technologies, it's likely that a commercial IIC system might eventually see the light of day.

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— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano