11.6 Functional requirement of GCR

3GPP43.069Release 16Stage 2TSVoice Broadcast Service (VBS)

The process in the GCR for RANflex and without RANflex configurations is shown in figure 8.

The process in the GCR for RANflex configuration with group call redundancy is shown in figure 8A. Figure 8A does not show details on GCR restoration (see subclause 5.3.3).

Service subscriber initiated call

If the GCR receives an interrogation request for a call initiated by a service subscriber who is located in the MSC area of the associated MSC, the GCR calculates the broadcast call reference from the Group ID and the originating cell ID.

If the broadcast call reference was successfully calculated, the GCR checks whether a VBS call with that broadcast call reference is already on-going.

If the call is not marked as on-going, the GCR checks whether an anchor MSC address is stored in its broadcast call reference record. If this is the case and initial talker information is not yet stored, a positive response including the anchor MSC address is returned to the MSC, the initial talker information (IMSI, originating cell id) of the initiating service subscriber is stored in the GCR and the process returns to the idle state. If anchor MSC address and initial talker information are stored (this is the case where the associated MSC is relay MSC, and timer T3 is running, i.e. broadcast call setup is in progress but the call is not yet fully established ), a negative response indicating "on-going call" is returned to the MSC and the process returns to the idle state. If no anchor MSC address is stored ( i.e. the associated MSC is anchor MSC with respect to this broadcast call reference) the GCR marks its broadcast call reference record with ‘on-going call’ and returns a positive response including the broadcast call attributes to the MSC and the process returns to the idle state.

If the broadcast call reference could not be successfully calculated from the Group ID and the originating cell ID, the GCR returns a negative response indicating ‘failure’ to the MSC and the process returns to the idle state.

If the call was marked as on-going , the GCR returns a negative response indicating ‘on-going call’ to the MSC and the process returns to the idle state.

IAM initiated call

If the GCR receives an interrogation request for a call initiated by a dispatcher or by a service subscriber who is not located in the MSC area of the associated MSC, the GCR checks the calling party number of the initiator against the list of identities of dispatchers which are allowed to initiate the voice broadcast call and against the prefix for VBS plus broadcast call reference in order to determine whether the initiator is allowed to set-up the call. If the check is successful the GCR checks whether a VBS call with the same broadcast call reference is already on-going.

If the call is not marked as on-going, the GCR marks its broadcast call reference record with ‘on-going call’ and returns a positive response including the broadcast call attributes to the MSC and the process returns to the idle state. In addition the GCR shall delete stored initial talker information (if any).

If the calling party number check was not successful, the GCR returns a negative response indicating ‘failure’ to the MSC and the process returns to the idle state.

If the call was marked as on-going , the GCR returns a negative response indicating ‘on-going call’ to the MSC and the process returns to the idle state.

Anchor MSC triggered call

If the GCR (associated to a relay MSC) receives an interrogation request for a call triggered by the anchor MSC, the GCR returns a positive response to the MSC including:

– the list of cells inside the MSC area of the requesting MSC in which the call is to be sent; and

– the stored initial talker information (if any) to the MSC;

and:

– marks its broadcast call reference with "on-going call";

– deletes the stored initial talker information (if any)

and the process returns to the idle state.

VMSC triggered call (in a RANflex configuration)

If the GCR (associated to a group call serving MSC) receives an interrogation request for a call triggered by the VMSC, the GCR

– calculates the broadcast call reference from the Group ID and the originating cell ID;

If for the calculated broadcast call reference the record is marked with "on-going call" or initial talker information are already stored, a negative response indicating "on-going call" is returned to the GCSMSC and the process returns to the idle state. Otherwise the GCR:

– stores the initial talker information (IMSI and originating cell ID received with the request); and

– returns a positive response including broadcast call reference and, if the group call serving MSC is a relay MSC, the anchor MSC address.

Call release

If the GCR receives a call released indication from the MSC, the ‘on-going call’ indicator in the broadcast call reference record is reset, the initial talker information is deleted (if any) and the process returns to the idle state.

Figure 8: Process in the GCR (sheet 1 of 3)

Figure 8: Process in the GCR (sheet 2 of 3)

Figure 8: Process in the GCR (sheet 3 of 3)

Figure 8A: The Process in the GCR for RANflex with group call redundancy (sheet 1 of 4)

Figure 8A: The Process in the GCR for RANflex with group call redundancy (sheet 2 of 4)

Figure 8A: The Process in the GCR for RANflex with group call redundancy (sheet 3 of 4)

Figure 8A: The Process in the GCR for RANflex with group call redundancy (sheet 4 of 4)

Figure 8B: Procedure Synchronize Transient Data