MC clients residing on non-3GPP devices receive MBMS bearer announcements from the MC system, MC clients share the details of the MBMS bearer received in MBMS bearer announcement to the MC gateway UE. This enables the MC gateway UE to start monitoring the corresponding MBMS bearer.
Figure 11.5.3.3.1-1 illustrates the procedure for handling the MBMS bearer announcement by the MC client and the MC gateway UE.
Pre-conditions
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The MC client has been configured with the necessary parameters to enable the use of the MC gateway UE.
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The MC client successfully completed service authorization via MC gateway UE.
Step 1.
The MC service server establishes the MBMS bearer(s) according to the procedures defined in
TS 23.468. Service description associated with the MBMS bearer(s) is returned from the BM-SC.
Step 2.
The MC service server provides service description information associated with the MBMS bearer to the MC client residing on non-3GPP devices via MC gateway UE.
Step 3.
The MC client sends the MC GW MBMS bearer announcement to the MC Gateway UE containing the MBMS bearer related information received from the MC service server.
Step 4.
The MC gateway UE stores the information associated with the TMGI(s). The MC gateway UE uses the TMGI and other MBMS bearer related information to activate the monitoring of the MBMS bearer.
Step 5.
The MC gateway UE that enters or is in the service area of at least one announced TMGI notifies to the MC client that it can receive data over MBMS by sending the MC GW MBMS listening status report. The MC GW MBMS listening status report also contains the details of the non-3GPP transport resources related parameters. The MC gateway UE may choose to send the details of existing transport resources information as part of non-3GPP transport resources establishment parameters IE if existing communication channel can be reused.
Step 6.
The MC client establishes the transport resources with the MC gateway UE based on the parameters received in step 5 to receive the MC service data from the MC gateway UE, if these parameters are not referring to any of the already established transport resources. The MC Gateway UE forwards the MC service data it received over the MBMS bearer from the MC service server to the MC client over this transport resources.
Step 7.
The MC client sends the MBMS Listening Status Report to the MC service server indicating that it is able to receive the media over MBMS.
Whenever the MC client detects that traffic received from MC service server is MapGroupToBearer message and if the MC client participates in the group session or communication identified by the MapGroupToBearer message then it should inform the details contained in the MapGroupToBearer message to MC gateway UE. When the association of group call, MBMS bearer and the MC GW service ID of the MC client is known to the MC gateway UE, it can forward the traffic received over MBMS bearer accordingly.
Figure 11.5.3.3.2-1 illustrates the procedure for handling the MapGroupToBearer message by the MC client and the MC gateway UE.
Pre-conditions
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The MC client has been configured with the necessary parameters needed for connectivity with the MC gateway UE.
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The MC client successfully completed service authorization via MC gateway UE.
Step 1.
The MC service server sends a MapGroupToBearer message over a previously activated MBMS bearer to all users that will receive the call over an MBMS bearer. The MapGroupToBearer message includes association information between the group call and MBMS bearer. The MapGroupToBearer message includes MC service group ID and information about the media stream identifier of the activated MBMS bearer and may include the identifier (i.e. the TMGI) of the MBMS bearer broadcasting the call.
Step 2.
If the MC client is participating in the MC group communication identified by the MapGroupToBearer message, it sends the details contained in the MapGroupToBearer message to the MC gateway UE through MC GW MapGroupToBearer request message.
Step 3.
The MC gateway UE on receiving the MC GW MapGroupToBearer Request message from the MC client it maintains the association between the GW MC Service ID and the corresponding MBMS sub channel.
Step 4.
The MC gateway UE sends the MC GW MapGroupToBearer response message to the MC client which contains the details of the non-3GPP transport resources related parameters. The MC gateway UE may choose to send the details of existing communication channel information as part of non-3GPP transport resources establishment parameters IE if existing transport resources can be reused.
Step 5.
The MC client establishes the communication channel with the MC gateway UE based on the parameters received in step 4 to receive the MC service group communication data from the MC gateway UE, if these parameters are not referring to any of the already established transport resources. The MC Gateway UE forwards the MC service group communication data it received over the MBMS bearer from the MC service server to the MC client over this transport resources.
Step 6.
The MC service server sends the downlink media for the group communication session over the MBMS bearer.
Step 7.
The MC gateway UE checks which MC clients should receive the media of the MC group communication based on Step 3.
Step 8.
The MC gateway UE forwards the downlink media to the intended MC clients over the transport resources established as in step 5.