Officials provide more specifics about mission-critical push-to-talk (MCPTT) standard for LTE, FirstNet deployment

During his session presentation, Thiessen noted that Release 13 includes isolated E-UTRAN operation for public safety (IOPS), which addresses a key concern that many LMR users had about LTE. If an LMR base station loses its connection to the system controller, the LMR base station continues to act as a repeater that supports communications among all devices that are within range of the base station.

IOPS essentially allows LTE base stations to support similar functionality, if connection to the LTE network’s evolved packet core (EPC) is lost. When asked about how IOPS would be deployed, Thiessen said the roadmap still has to be determined.

“All of that, I would say, is implementation-specific,” Thiessen said during the session. “It’s up to each manufacturer to decide how they’re going to do that—what part is hardware and what is software. How quickly it shows up is really a function of how much money is put on the table to buy it.

“I think there’s a lot of interest in this—the United Kingdom has been playing in this, as well as South Korea and the United States. This is something that everybody is interested in; it’s just a matter of time before we start to see it in commercial deployments.”

One reason for Thiessen’s optimism that IOPS will be deployed widely is that carriers see commercial benefits associated with leveraging the capability.

“This was largely led by the vendor community,” he said. “This wasn’t something, from a FirstNet perspective, that we drove in and led. This was something that industry saw a need for and drove it in themselves, so I think we will see this show up sooner rather than later.”

Thiessen noted several other characteristic included in the new MCPTT standard:

• MCPTT utilizes adaptive multi-rate (AMR) wideband as the mandatory vocoder for MCPTT, but the enhanced voice services (EVS) vocoder can be deployed by operators in addition to AMR wideband. For more information on this subject, see this blog by Prochaska.
• Call-setup times that are faster than those required for P25 systems.
• Group communications that allow for the broadcast distribution of a single message in a one-to-many scenario, instead of having to repeat the message individually to each user in a cell sector, which would be inefficient.
• The ability to “discover” other LTE devices that are within direct-mode communications range, which is not something that LMR systems support today.