8.15 MBMS UE Linking/De-linking mechanism
23.2463GPPArchitecture and functional descriptionMultimedia Broadcast/Multicast Service (MBMS)Release 17TS
MBMS UE Linking is the process by which UE MBMS context(s) is (are) provided to an Iu-mode RAN.
MBMS UE linking procedure is performed when the UE is PMM-CONNECTED at least in the following cases.
– When a UE which has a MBMS UE context is moved to the PMM CONNECTED state and a PS RAB is established. This may happen at any point in time e.g. before, during and between Sessions.
– When a UE joins the MBMS bearer service and is in the PMM CONNECTED state due to an existing PS RAB. This may happen at any point in time e.g. before, during and between Sessions.
– When a UE is moved to the PMM CONNECTED state via the MBMS Service Request procedure. This may happen at any point in time during a MBMS session.
The UE linking is performed to link a specific UE to an MBMS service. It provides the SRNC/Iu-mode BSC with a list of MBMS service identifiers (including TMGI) for MBMS bearer services activated by the UE. If no MBMS service context exists for this particular MBMS bearer service then the SRNC/Iu-mode BSC creates an MBMS service context after this procedure.
NOTE: the MBMS Bearer Context is referred to as the MBMS Service Context in 3GPP RAN specifications
MBMS UE De-Linking denotes the process where a MBMS UE context is removed from the RAN.
MBMS UE De-Linking procedure is performed if the UE is PMM-CONNECTED and has been already linked towards the RAN at least when it initiates MBMS Multicast Service Deactivation procedure. This may happen at any point in time during the whole MBMS service availability i.e. before, during and between MBMS sessions.
The UE De-Linking is performed to unlink a specific UE from a MBMS service. The entry for this UE is removed from the concerned MBMS service context(s) in the SRNC.