Content for TS 23.247 Word version: 18.7.0

4.2 MB service provisioning p. 15

An example for the sequence of phases for multicast data provisioning is described in the Figure below:

The following phases are performed for a specific UE:

UE Session Join: UE Session Join is the process by which a UE joins an MBS Session, i.e. the UE indicates to 5GC that such UE wants to receive Multicast data identified by a specific MBS Session ID.
UE Session Leave: UE Session Leave is the process by which a UE leaves a MBS Session, i.e. the UE no longer wants to receive Multicast data identified by a specific MBS Session ID.

The following phases are performed for a specific service:

MBS Session Creation: It is the phase that the information of Multicast MBS session is created as described in clause 4.3. This step is optional.
Service announcement: Service announcement is used to distribute information toward UEs about the service required for service reception (e.g. IP multicast address(es)) and possibly other service related parameters (e.g. service start time). This step is optional.
Session Establishment: It is the phase that Multicast MBS session is established as described in clause 4.3.
No data receiving: It is the phase when no multicast data is received by 5GC. This step is optional.
Data transfer: It is the phase when Multicast data are transferred to the UEs.
Session Release: It is the phase that the resources for Multicast MBS session is released as described in clause 4.3.
Session Deletion: It is the phase that Multicast MBS session is deleted as described in clause 4.3.

NOTE:
After session establishment, Multicast MBS session state could be switched between Active and Inactive several times, triggered by AF or User Plane event, see clause 7.2.5. 5GC further updates Multicast MBS session state towards NG-RAN nodes after Session Establishment.

The phase of Multicast data provisioning is illustrated with the following example of timeline:

An example for the phases of broadcast data provisioning is described in the Figure below:

The following phases are performed for a specific service:

MBS Session Creation and establishment: MBS Session Creation is used by the AF to create the MBS Session towards 5GC. MBS session creation can occur in several steps (e.g. TMGI allocation, provisioning information about MBS session, request to activate the MBS session). The last step of the MBS session creation triggers resource establishment for transmitting the DL Broadcast data between 5GC and NG-RAN.

NOTE:
For broadcast communication, after MBS Session Creation and Session Establishment, the established resources are not only between 5GC and NG-RAN, but also between the AF to 5GC.
Service announcement: Service announcement is used to distribute information towards UEs about the service required for service reception (e.g. IP multicast address(es)) and possibly other service related parameters (e.g. service start time). This step can occur in parallel or after the MBS session configuration. However, TMGI allocation is required before. The information of the service announcement, is defined in clause 6.11.
Data transfer: It is the phase when broadcast data are transferred in the air interface.
Session Release and Deletion: It is the point at which there will be no more need to transmit Broadcast data. At Session Release, the resources in 5GS are released and the broadcast MBS session is deleted.

The phase of Broadcast data provisioning is illustrated with the following example of timeline: