G.3 MCPTT emergency group state

24.3793GPPMission Critical Push To Talk (MCPTT) call controlProtocol specificationRelease 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The MCPTT emergency group state is the MCPTT client’s perspective of the in-progress emergency group state which is managed by the controlling MCPTT function. The MCPTT emergency group (MEG) state is managed by the MCPTT client to enable the requesting of MCPTT emergency-level priority as early as possible in the origination of an MCPTT emergency group call. High-level characteristics of this state are captured in table G.3-1.

Table G.3-1: MCPTT emergency group state

MCPTT emergency group state values	State-entering events	Comments
MEG 1: no-emergency	initial state prior to any call activity Emergency group call cancel request received on behalf of another user from the MCPTT server Emergency group call cancel response (success) in response to initiator’s request
MEG 2: in-progress	Emergency group call response received (confirm) to initiator’s emergency group call request Emergency group call request received (on behalf of another user)	In this state, all participants in calls on this group will receive emergency level priority whether or not they are in the MCPTT emergency state themselves.
MEG 3: cancel-pending	Emergency group call cancel request sent by authorized user	The controlling MCPTT server may not grant the cancel request for various reasons, e.g.if another users in an MCPTT emergency state is transmitting the media or if based on the local policy, the requesting user is not an authorized user to cancel the group emergency state.
MEG 4: confirm-pending	Emergency group call request sent by initiator	The controlling MCPTT server may not grant the call request for various reasons, e.g., the MCPTT group is not configured as being emergency-capable so it can’t be assumed that the group will enter the in-progress state.