Whenever the MC client receives UnmapGroupFromBearer message and if the MC client participates in the group session or communication identified by the UnmapGroupFromBearer message then it should inform the details contained in the UnmapGroupFromBearer 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 remove the association and stop forwarding of the traffic received over MBMS bearer accordingly.
Figure 188.8.131.52.2A-1 illustrates the procedure for handling the UnmapGroupFromBearer message by the MC client and the MC gateway UE.
The MC client has been configured with the necessary parameters needed for connectivity with the MC gateway UE.
The MC client successfully completed service authorization via MC gateway UE.
If the MC client is participating in the MC group communication identified by the UnmapGroupFromBearer message, it sends the details contained in the UnmapGroupFromBearer message to the MC gateway UE through MC GW UnMapGroupToBearer request message.
The MC gateway UE on receiving the MC GW UnMapGroupToBearer Request message from the MC client it removes the association maintained between the GW MC Service ID and the corresponding MBMS sub channel.
The MC service server can choose to instruct some MC clients to send the MBMS bearer suspension report when notified by RAN. When the MC clients are residing on non 3GPP devices, MC gateway UE would be the one listening on the MBMS bearers. When RAN decides to suspend the MBMS bearer it indicates the MC gateway UE. MC gateway UE to notify the MC clients it is serving so that MC clients can report the same to the MC service server. This procedure is applicable only if the MC client is instructed to report the MBMS bearer suspension. Irrespective of whether the MC clients need to send the MBMS bearer suspension report to the MC service server, MC gateway can choose to notify the MC clients it is serving whenever RAN suspends the MBMS bearer. MC clients can then decide to send the MBMS bearer suspension report to the MC service server only if they are instructed by the MC service server.
Figure 184.108.40.206.3-1 illustrates the procedure for MC clients residing on non-3GPP devices reporting the MC service server about the MBMS bearer suspension.
The MC gateway UE listening on the MBMS bearer has to report the MBMS bearer quality to the MC clients so that MC clients can report the same to the MC service server. MC Gateway UE monitors an MBMS bearer to receive MC service media. Based on the received quality (e.g. radio level quality) the MC gateway UE needs to inform the MC Clients which requested the MC gateway UE to listen on MBMS bearer, whether it is able to receive the MC service media on the MBMS bearer with sufficient quality or not the MC Clients can inform the MC service server accordingly.
Figure 220.127.116.11.4-1 illustrates the procedure for MC clients residing on non-3GPP devices reporting the MC service server about the MBMS bearer quality.
There is an MBMS bearer activated and the MBMS bearer information is announced to the MC gateway UE.
The MC gateway UE is located in the MBMS broadcasting area
The MC gateway UE monitors SIB-13 (or SIB-20) and (SC-)MCCH to receive the modulation and coding scheme.
The MC gateway UE monitors the cell specific reference signal and when MBSFN transmission is used, the MBSFN specific reference signals.
The MC gateway UE follows the Step 1 of the procedure as described in clause 10.7.3.6.2 for the MC service UE. The corresponding MBMS bearer quality information is forwarded to all the MC clients which have asked the MC gateway UE to listen on the particular MBMS bearer.
If the MBMS bearer quality reaches a certain threshold, the MC gateway UE sends an MC GW MBMS bearer quality report to the MC client. The threshold is used to define the MBMS listening status, which indicates if the MBMS bearer quality has been acceptable or not to receive a specific MC service media. If the MBMS bearer quality is mapped to a different MBMS reception quality level, the MC gateway UE may send an MBMS Bearer Quality report including the MBMS reception quality level to the MC Client.