Few things associated with FirstNet are certain, because the organization is still in a formative stage with no established network design or business plan. For instance, some argue that FirstNet is moving too fast and has not sufficiently considered public safety, while others claim FirstNet should have at least some tangible network deployed as we near the two-year anniversary of Congress passing the law creating it.

One of the few things that everyone agrees on is that the $7 billion that Congress has earmarked for FirstNet is not nearly enough to pay for the buildout of a nationwide public-safety-grade broadband network, much less fund the ongoing operations of such a system. While the size of the shortfall has been a matter of considerable debate—estimates have ranged from as low as $5 billion to more than $60 billion. Everyone agrees that it will exceed $7 billion, and Congress does not seem inclined to invest any more money into the project.

Beyond the $7 billion, the only other asset FirstNet has is 20 MHz of contiguous spectrum in the 700 MHz band—“beachfront property” in the world of radio airwaves. From the beginning, FirstNet board members were told by then-Acting Secretary of Commerce Rebecca Blank that “we would expect that you will arbitrage that spectrum to generate additional funds to build this network,” FirstNet Chairman Sam Ginn said during a speech last year.

Last month, FirstNet General Manager Bill D’Agostino issued a statement reinforcing the notion that some version of spectrum arbitrage will be part of the FirstNet business model, although D’Agostino also noted that “it’s not our only answer.”

Now, the notion of public safety sharing spectrum with commercial users is not new. When Morgan O’Brien first proposed the idea that there should be a public-safety broadband network in 2006, he envisioned public safety having 30 MHz of spectrum, so the excess spectrum could be leased to commercial entities. Revenue from such deals would pay for the buildout and maintenance of the public-safety network.

When the Public Safety Spectrum Trust (PSST) was tasked with creating a network with no money and no assets other than 10 MHz of spectrum, the FCC conducted an auction in early 2008 in which commercial carriers were supposed to bid on the right to build out a public-safety broadband network that also would be used for commercial purposes. But no qualifying bids were made, as commercial entities cited the additional costs of building to public-safety standards and the uncertainty regarding when public safety could preempt commercial users as key reasons.

Today, a new sharing model is being proposed by Rivada Networks to allow public safety and commercial entities to share a network in a manner that is beneficial to both sides. It is called dynamic spectrum arbitrage (DSA) and would be combined with the notion of tiered priority access (TPA)—a mandatory component to public safety, which requires that its communications be transmitted over its network, even if it means dropping commercial traffic at a given time—to enable first responders and commercial entities to share network resources in real time.

My first encounter with this proposal of dynamic spectrum arbitrage occurred at the Public Safety Communications Research (PSCR) event in Colorado last June. There were several compelling presentations on the event agenda, but arguably the biggest buzz came from those who visited the room where Rivada Networks’ officials were explaining how DSA/TPA would allow commercial entities to pay for the right to sell unused FirstNet bandwidth capacity but preserve the ability for first responders to ruthlessly preempt commercial users—if necessary—the moment an emergency happens.