16.14.12 Support of ISA for MBS Broadcast in NTN

An intended service area (ISA) is a geographical area that can be signaled for MBS broadcast services. The ISA(s) is broadcasted in SIB27 and associated to MBS broadcast service(s) by indicating the ISA identifier(s) in MCCH. It may be included in USD within target service area [46].

The NTN-capable UE supporting the MBS broadcast may initiate the broadcast MRB establishment procedure and prioritize the frequency providing these MBS broadcast service(s) when it is inside an ISA. The UE may initiate the broadcast MRB release procedure and no longer prioritize the frequency providing MBS broadcast service(s) when the UE leaves an ISA, as specified in clause 5.9.3 of TS 38.331 [12] and clause 5.2.4.1 of TS 38.304 [10].

NOTE: When using ISA(s) for MBS broadcast service reception or MBS service continuity, it is up to the UE implementation how to determine if it is in the ISA(s) of MBS broadcast service or not.