NR multicast/broadcast (MBS): PTM delivery, group communication

MBS Architecture and Delivery Modes

NR Multicast Broadcast Services, specified in 3GPP TS 23.247, introduces efficient one-to-many delivery in 5G NR. The architecture adds two new core network functions: MB-SMF for session management and MB-UPF for multicast user plane forwarding. MBS supports two delivery modes: Point-to-Multipoint (PTM) where a single transmission using a shared Group RNTI serves all UEs in a multicast area, and Point-to-Point (PTP) where dedicated unicast bearers deliver multicast content individually. The network dynamically switches between PTM and PTP based on group size — PTM is efficient for large…