One of the most important aspects of the FCC plan for a 700 MHz broadband network is that public-safety agencies will be able to roam onto commercial carrier networks operating in the 700 MHz band, giving first responders access to more than 50 MHz of spectrum and network capacity.

There are a bunch of debates surrounding this proposal. Will public safety need to roam on a daily basis, or will it only need to roam when disasters occur? Who pays when public safety roams and how much should be charged? Should public safety have priority or pre-emptive status when roaming?

While these questions and other technical/operational issues are receiving considerable attention, a more fundamental legal issue is being overlooked by many: Does the FCC have the authority to require commercial carriers to grant priority/pre-emptive roaming rights to public safety?

If the D Block is auctioned to a commercial provider, the FCC should be able to attach any roaming rules it deems appropriate for the D Block winner. Of course, if a guard band is needed — meaning an effective reduction of 40% of the D Block capacity using LTE, according to industry sources — and pre-emptive public-safety roaming were included in the rules, the price tag for the spectrum block likely would be far less than the $3 billion Congress projected. Still, there is little doubt that the FCC would have the authority to establish roaming rules.

Outside of the D Block, the FCC’s authority is much less clear. After all, commercial carriers like AT&T and Verizon spent $19 billion in the 700 MHz auction three years ago for spectrum based on the rules in place at the time — and those rules mentioned nothing about new public-safety roaming rules onto commercial networks.

In filings with the FCC, these carriers have made clear that they do not appreciate the notion that the FCC might change the rules of the game after spectrum has been bought and paid for. The strongest language has been associated with proposals to revamp the 700 MHz spectrum plan, but the implication is clear that all rule changes could be challenged in court.

Would a retroactive priority-roaming mandate be something that carriers would fight? Perhaps not, since public safety has long had priority-access privileges — the ability to be first in line when space on a network becomes available.

However, public-safety officials want pre-emptive access — not just first-in-line access but the ability to override existing users on the network during emergencies. Pre-emption means potentially kicking customers off the network or significantly reducing their performance. For carriers that live and die based on customer satisfaction, this notion understandably could be a problem, particularly if public-safety roaming occurs on a regular basis and is not as profitable as normal customer traffic.

With this in mind, it is paramount that the FCC’s legal authority to require roaming throughout the 700 MHz band be clarified quickly. If the FCC cannot impose its proposed roaming requirements on AT&T and Verizon, the agency’s plan looks even less attractive to public safety than it does today.

After all, what public safety wants is control of 20 MHz and the pre-emptive roaming on commercial networks operating on more than 40 MHz throughout the 700 MHz band. The FCC is proposing public safety control of 10 MHz and roaming on 50-plus MHz throughout the 700 MHz band.

However, if the FCC lacks the authority to impose public-safety roaming on AT&T and Verizon, then we could be talking about public safety controlling only 10 MHz of spectrum and having roaming rights on only a 3x3 MHz swath used by the D Block winner, which could be years behind AT&T and Verizon in deploying LTE. It’s hard to imagine the kind of scenario that anyone — public safety, policy-maker or lawmaker — envisioned for this much-anticipated public-safety network.

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