Content for  TS 23.379  Word version:  19.1.0

User regroup using the group creation procedure can be initiated by an authorized user creating a temporary group with a list of MCPTT users. The group ID for this temporary group can be provided at the time of group creation. The temporary group can be used by all MCPTT users in the list for two-way (non-broadcast) communication until deleted by an authorized user. Optionally, the group can be used for one-way (broadcast ) communication where the creator of the temporary group can make a broadcast group call, but the other MCPTT users can only listen to the group call and cannot respond.

Figure 10.6.2.10.2-1 below illustrates the temporary group creation, and optional broadcast call setup procedure and temporary group deletion initiated by an authorized user. Pre-conditions:

1. The authorized user is aware of the MCPTT users who will be included in the temporary group.

If the authorized user wishes to end the use of the temporary group, the procedure for group deletion described in TS 23.280 is followed.

The temporary group created using a preconfigured group can be a broadcast group or a non-broadcast group. The broadcast regroup is used for one-way communication where only an authorized MCPTT user is allowed to transmit and all other regroup members are only allowed to receive the communication (e.g. a call from a dispatcher to all regroup members). The non-broadcast regroup is used for two-way communication where all regroup members can transmit and receive (i.e. the regroup group call behaves like a normal non-broadcast group call). The broadcast regroup satisfies the temporary group-broadcast group requirements defined in TS 22.280. A broadcast group regroup call using preconfigured groups can be achieved by first regrouping MCPTT groups into an MCPTT regroup group, making the broadcast group call on the regroup group, and then cancelling the preconfigured group regroup.

The broadcast group regroup call procedure using preconfigured group allows an authorized MCPTT user to initiate a broadcast call to a set of MCPTT groups, which are regrouped only for the duration of the broadcast call. The regroup is cancelled at the end of the broadcast call to prevent users from talking back on the regroup group. This procedure requires that the authorized MCPTT user is a group member of at least one of the MCPTT groups included in the regroup operation. Figure 10.6.2.11.2-1 illustrates the procedure to initiate a broadcast group regroup call using a preconfigured MCPTT group. Pre-conditions:

• MCPTT clients 1, 2, and 3 are registered with the MCPTT service.
• The group configuration for the MCPTT regroup group have been preconfigured in MCPTT clients 1, 2, and 3, and MCPTT clients 1, 2 and 3 have received the relevant security related information to allow them to communicate in the regroup MCPTT group.
• MCPTT client 1 is authorized to initiate a group regroup using the preconfigured regroup procedure.
• MCPTT client 1 is aware of a suitable preconfigured group whose configuration has been preconfigured in the MC service UEs of the MCPTT users who will be regrouped.
• MCPTT client 1 is affiliated to group 1, MCPTT client 2 is affiliated to group 2, and MCPTT client 3 is affiliated to group 3. Group 4 is used as the regroup group.