Work on writing the standard for mission critical push-to-talk (MCPTT) voice over LTE was completed just in time to be included in LTE Release 13 before standards body 3GPP ‘froze’ any further development last month (March 2016). Any further work items now move into Release 14.
The final work was done at a 3GPP plenary meeting in Gothenburg, Sweden in the second week of March. There had been concerns the work on MCPTT might not be finished in time to make the cut off point for the Release 13. However, for the first time in 3GPP history, a live conference call was held during the meeting to complete the final key remaining issue - a decision on a voice codec for MCPTT.
This is good news for countries looking to augment or replace their existing land mobile two-way radio networks with broadband LTE services, so they can access fast data applications. This is of particular interest to emergency services organisations, but also for other verticals that rely on mission critical communications.
The MCPTT standard also includes support for direct mode communication (where radio talks directly to radio without going through the network) and a discovery feature that enables a user to know if other radios are within direct mode range. In addition, there is a relay feature that enables a user out of coverage to connect to an LTE network using a direct mode connection with an LTE device within coverage range.
The completion of the MCPTT work still leaves work on mission critical video over LTE and mission critical data over LTE for Release 14, along with some other functions. Work for Release 14 is scheduled for completion in March 2017.