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End-to-End Mission Critical Push-to-Talk with Direct Mode Operation


Current P25 Land Mobile Radio (LMR) systems are the gold standard when it comes to mission critical voice communication. It is, therefore, essential for FirstNet’s Long Term Evolution (LTE) standards-based, nationwide, Public Safety Broadband Network (PSBN) to achieve mission critical voice services that are at least on parity with current LMR systems. The first responder technical community has worked with the 3GPP standards body to define public safety centric features and enhancements. Starting with Release 8 (e.g., B14 LTE support) the efforts today stand at Release 13 with specifications for Mission Critical Push to Talk (MCPTT) on LTE networks. Other enhancements such as Multicast-broadcast single-frequency network(MBMS), Quality of Service (QoS), ProSe, High Power UE, LTE relay, etc. were also specified in Releases along the way.

Meet the Team

Principle Investigator: Robert Escalle
Sonim Technologies

Sonim Technologies logo with tagline "Build for Life"

Project Overview

The goal of this project is to deliver an open source platform that significantly advances the state-of-the-art for mission critical voice by addressing both on-network and off-network end-to-end mission critical PTT. The team’s vision is to offer a 3GPP R13 compliant MCPTT platform with both client and server side elements that will be seamless and fully interoperable with existing nationwide narrowband assets. This platform will help accelerate adoption of mission critical voice services on PSBN without need for proprietary software and hardware. Since long term users of LMR systems are best positioned to gauge the mission critical experience delivered by our proposed end-to-end solution, the team will work in coordination with first responders from Atlantic City Police Department and Fairfax County, Virginia, as the test partners of the end-to-end solution.

 << Back to the PSIAP 2017 - Public Safety Mission Critical Voice Page

Created September 28, 2017, Updated December 30, 2022