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

LAS VEGAS—Functionalities associated with the new mission-critical push-to-talk (MCPTT) standard for LTE are designed to meet or exceed the capabilities and performance benchmarks for existing land-mobile-radio (LMR) systems, but real-world testing is needed to determine whether MCPTT can overcome some physics limitations that will allow it to meet the needs of first responders, officials said during an IWCE 2016 session on the subject.

On March 11 in Sweden, 3GPP—the standards body that oversees development of the LTE standard—approved the components of MCPTT over LTE as part of LTE Release 13. With the action, vendors now are able to develop products that meet the much-anticipated MCPTT standard.

FirstNet’s request for proposal (RFP) calls for LTE Release 13 with MCPTT to be implemented in its nationwide public-safety broadband network (NPSBN) within two years of a contractor being selected and agreeing to the terms of the 25-year deal. If a contractor receives the award on Nov. 1 as proposed in the RFP, MCPTT functionality could be available on the network to 60% to 80% of the country (by population) in late 2018 or 2019.

But Dean Prochaska, FirstNet’s director of standards, said that the timeline proposed in the RFP “are just targets that we’ve set out there” and that MCPTT deployment could depend on the product-development cycles pursued by vendors. Prochaska also noted that MCPTT is not the top priority for FirstNet.

“Our first focus is that this is a data network,” Prochaska said. “Within the RFP, we have targeted timelines for other types of things to eventually merge, but that could be a long time in the future. We’re more concerned about data.”

But vendor interest in MCPTT is high, with some PTT-over-cellular developers indicating that they already have plans to alter their existing products to comply with the MCPTT standard in LTE Release 13. Not only is there a potential market for the product in the United States in the near future, but several other countries—most notably, South Korea and the United Kingdom (UK), both of which pushed the MCPTT standard—also have expressed interest in such products.

Andrew Thiessen, deputy program director for Public Safety Communications Research (PSCR), said the new MCPTT standard was developed in LTE Release 12 and Release 13 to address all of the concerns that public-safety officials had about the potential use of LTE technology for mission-critical voice—most notably, the ability to communicate even without the use of macro-network infrastructure, such as eNodeB base stations and the evolved packet core (EPC).

“In Release 12, where we really got started in public-safety work, the idea was to try to create something that would allow for mission-critical push to talk to occur over LTE,” Thiessen said. “As we developed these features in Release 12, we tried to—at a minimum—provide the same functionality that land mobile radio provides today, with the idea being that one day you might transition from land mobile radio to LTE, so it’s at least got to do what you have in land mobile radio.”