Public safety’s voice needs

For the past 80 years, public-safety agencies have relied on LMR systems to provide mission-critical voice communications to first responders in the field. Often hardened to withstand natural disasters or power outages, the primary characteristic of these systems is that they work, even when commercial wireless networks and the electric power grid are down.

Such reliability also can become the hallmark of IP-based LTE systems, if designed properly and devices are ruggedized, Wright said. After all, IP was created to help the government protect valuable data stored in multiple locations, so a nuclear attack to a single location would not cripple access to the information, he said.

“IP itself was inherently designed for disaster recovery,” Wright said. “It was created to survive nuclear attacks — that’s why the Department of Defense created it. It’s DNA is basically to be bulletproof.”

While LTE networks can be built to meet public safety’s reliability requirements, current iterations of the technology do not support voice at all, much less mission-critical voice. Commercial-grade voice is expected to be provided on carrier LTE networks during the next year, but no sources believe that first responders should use the solution as a primary source of voice communication.

When will 3GPP — the LTE standards organization — develop a mission-critical voice solution for the 4G technology, particularly one that would provide peer-to-peer communications that are so valuable to firefighters at emergency incidents? It probably will never happen, according to John Vaughan, senior vice president of global marketing and business development for Harris RF.

“I don’t think public safety, as a market is big enough — compared to the billions of people on cell phones — that 3GPP would be likely to change LTE for the sake of push-to-talk,” Vaughan said. “LTE will never do peer-to-peer, because it’s fundamentally not architected that way and never will be. However, we absolutely agree that peer-to-peer communications is fundamentally important to public safety.”

To address these technical issues, Vaughan said he believes a mission-critical voice-over-IP (VoIP) push-to-talk application can be developed that can operate on any IP-based broadband network. This type of solution would be helpful in that it could be used over a variety of platforms — LTE, Wi-Fi or fiber, for instance — and would not be tied to any single network technology, he said.

“If my broadband network is an IP network, and I’ve configured my voice solution as an IP solution, then it can work on more than just LTE,” Vaughan said. “We have always wanted ubiquitous coverage, when maybe what we really need is ubiquitous connectivity. It’s a big shift in thinking … it’s a very different way of thinking about delivering mission-critical voice.”

Whatever the solution, Vaughan said that it is important that it be standardized throughout public safety — a notion echoed by Mario DeRango, chief architect of government and public safety at Motorola Solutions.

“There is angst about anything proprietary,” he said.

Another current shortcoming of LTE is that it does not offer one-to-many communications, but DeRango said that the LTE standard calls for support of a multicast/broadcast service. However, that function requires guaranteed spectrum availability, which necessitates the need for additional airwaves, he said.

“You probably need the D Block to really pull this off in some of the large cities,” DeRango said. “The extra [spectrum] is going to be key to enabling the larger cities to be able to do voice and still do all the video and data that they want to do with this LTE network.”

In terms of resolving the important talkaround issue, several sources noted that wireless mesh technologies can provide similar functionality as LMR direct mode, although DeRango noted that a 200-mW smartphone device is not going to have nearly as much range as a multiwatt land-mobile radio.

Wright said that he is confident that a talkaround solution can be developed.

“Given the right funding to do these things … and the right innovation environment, we’re going to find a solution to this problem,” Wright said. “It could be an application. It could be an embedded module. Or, it could be a multimode device — one that has the half-duplex push-to-talk capability but has embedded into it a module or application that provides the talkaround.”

Several other sources reiterated the potential value of federal dollars that could be used to pay for development of public-safety-specific broadband technology — one piece of legislation calls for $500 million in such funding — so that first responders can have greater assurance that solutions have been developed properly.

Vaughan said that he believes a guiding principle in development should be to ensure that mission-critical voice over broadband mirrors current LMR solutions.

“What we really want to do is pick that up and put it into LTE,” he said.

But Wright said that it is important that public safety be open to new ideas and approaches, as long as the solution meets the needs of first responders.

“Are you telling me that, for the next 50 years, public-safety voice has to act the way it has for the previous 50 years. Is that the definition of innovation?” Wright said. “I think we’ve got to change the way we think about this problem.”

Mustarde agreed.

“The future really has to be, ‘Look, let’s not allow the technology that we currently have to define how we are going to use technology in the future, because technology changes,” he said. “I don’t have a Sony Walkman on my hip any more, but I still listen to music. It’s the listening to music that defines how technology will evolve, and I can do so much more with iPhone, iPad or smartphone than I could ever do before.”