In-building coverage for FirstNet wanted, but many details remain unknown

In-building coverage for FirstNet is important for public safety, but consensus policies still need to be developed and considerable education is needed to make in-building coverage for first responders subscribing to the nationwide FirstNet system a reality, according to speakers on a panel exploring the topic.

As part of its nationwide contract with FirstNet, AT&T is providing FirstNet public-safety subscribers with prioritized and preemptive access to its entire network—not just operations on 700 MHz Band 14 spectrum licensed to FirstNet. This capability includes AT&T’s existing in-building infrastructure, according to Fred Scalera, a market development manager for AT&T’s FirstNet initiative.

“We actually have 6,000 DAS systems installed nationwide and over 40,000 Wi-Fi hotspots,” Scalera said during a session that was part of a summit hosted by the Safer Buildings Coalition. “When you hit that DAS [distributed antenna system] or that Wi-Fi, it will give public safety the same experience as if they’re on the LTE network … They will have the same priority and preemption off that [in-building] system as they would if they were on the [outdoor LTE] network—that’s a key piece.”

Scalera said that the FirstNet state plans—adopted by all 56 states and territories as of last month—depicted the planned outdoor LTE coverage for FirstNet. While indoor-coverage projections were included in the state plans, those estimates were based on the in-building coverage that would be provided from signals from AT&T’s outdoor network penetrating inside of facilities, Scalera said.

Of course, wireless signals penetrating buildings can be difficult, particularly for structures that meet the Leadership in Energy and Environmental Design (LEED) program criteria, because those facilities use energy-efficient windows and other materials that significantly degrade wireless communications from outdoors. As a result, in-building systems have become much more commonplace for both commercial cellular and public-safety LMR communications.

FirstNet is designed to be a public-safety network that uses a commercial cellular technology—LTE—to provide first responders with wireless broadband connectivity. Leveraging existing AT&T in-building assets makes sense, but the coverage needs for commercial cellular providers and public safety can be very different, according to Tom Chamberlain, an area vice president for Westell Technologies, a manufacturer of in-building solutions.

“The general areas that are excluded [for commercial cellular systems] in the buildings are the stairwells, the utility rooms, the fire control panel,” Chamberlain said during the session. “So, when you start talking about dollars and infrastructure, you can do [leverage commercial assets], but you have balance that between what the carrier needs are and what public safety needs. You have to figure out where that makes the most sense.

“You are going to have to put antennas where you otherwise would not have to put them. What that does in a large building sometimes is that really messes with your [radio-frequency] link budget, because you’re going to have to more remotes—or you’re going to have to use higher power—and the cost goes up. You’re sharing public-safety needs and commercial needs, but you’re sharing a higher cost overall.”