DALLAS—At least one major U.S. wireless carrier is deploying neutral-host distributed antenna systems (DAS) to deliver high-bandwidth indoor coverage inside of buildings that can be shared with other carriers, but financial and operational factors prevent the same indoor solutions from being leveraged by public-safety personnel in the same locations.

AT&T is deploying neutral-host DAS solutions, which are largely “future proof” because they are flexible enough to support multiple technologies and capacity as circumstances change, Jim Parker, senior manager for AT&T’s antenna solutions group, said during a panel discussion on antenna-deployment challenges at the Antenna Evolution Focus Day prior to the LTE North America conference. But using these shared indoor DAS assets to support public-safety LMR and LTE communications can be complicated, so the carrier typically does not do it, he said.

“The public-safety requirements tend to be more stringent than the commercial DAS requirements,” Parker said during the session. “Therefore, when we deploy a public-safety DAS, it’s a separate layer. It’s a separate DAS basically, because it requires more battery backup and the enclosures all have to be NEMA-rated, so that they are waterproof to prevent water intrusion.

“If we applied that standard for the commercial DAS, then our costs would go through the roof. Because, when you’re building out commercial DAS, the requirements are very, very different.”

Panel moderator Ken Rehbehn, a principal analyst for 451 Research and a volunteer firefighter in the Washington, D.C., area, said he believes that public-safety personnel would like to have the opportunity to leverage even commercial-grade DAS assets inside of a building instead of struggling to communicate during emergency responses.

“That’s actually pretty upsetting. I’m really surprised,” Rehbehn said after Parker spoke. “We’re waiting to deploy public-safety-coverage systems because we want to have a higher quality system. And, since we’re going to have the highest quality possible for the indoor system for public safety, we’re not going to deploy it at all—screw it.

“That is unbelievable, because there are so many buildings that are uncovered. We don’t need the perfect solution; we just need enough of the solution to get the job done … We just don’t have enough public-safety indoor coverage today. It should be relatively straightforward to have a repeater-based adjunct to an indoor system to provide that basic public-safety coverage.”

Parker said there are “a lot of really good reasons” for the more stringent indoor-coverage requirements for public safety, noting that carrier DAS systems do not include battery backup that is as robust as first responders need, because “we assume that the building will be vacant [of commercial customers]” soon after a fire or other emergency occurs that requires general evacuation.

In addition, an audience member who said he was with Verizon noted another problem for a carrier that shares an indoor DAS solution to support public safety.

“Do you really want emergency personnel going in, depending on that network and have it fail?” the audience member asked. “What’s the PR going to look like: ‘Six firefighter killed as AT&T or Verizon’s network failed?’”

But Rehbehn said the problem with the scenario is that public-safety personnel entering such buildings “are getting honks on their trunked system” indicating that no indoor coverage is available. As a result, first responders in these situations have to resort to daisy-chained communications to personnel at key locations, which is inefficient and can be difficult.

“It’s a horrible situation, and even a good-enough commercial system would be grand—absolutely fabulous,” Rehbehn said. “We have backup battery, because we will roll a repeater system on a battalion chief’s car to the scene when things start going along. But to have the building covered comprehensively by a mid-grade commercial solution would be awesome.

“We do have backups, even if that system fails, but they are very clumsy to use.”

Another challenge noted by panelist Keith Radousky, CTO of Quintel, is that many public-safety LMR systems operate on UHF and VHF bands that are not supported by typical carrier DAS solutions today.