4 General Architecture for EUTRAN MBMS
36.4403GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)General aspects and principles for interfaces supporting Multimedia Broadcast Multicast Service (MBMS) within E-UTRANRelease 17TS
Figure 4-1 General Architecture for E-UTRAN MBMS
Figure 4-1 shows a simplified architecture for MBMS in LTE/SAE. It consists of EPC functional entities and E-UTRAN nodes. Functions of MBMS EPC entities are defined in TS 23.246 [8]. Functions of MBMS E-UTRAN nodes are defined in TS 36.300 [9]. It should be noted that TS 36.300 [9] also allows MCE be deployed inside eNodeB.
Interfaces related to E-UTRAN (i.e. M1, M2 and M3) are introduced in this document. For MBMS, control signaling and user plane data packet are distributed from the EPC to E-UTRAN through different interfaces.
● Control plane interfaces
M3, M2 interface are pure control plane interfaces.
M3 between MME and MCE mainly carries MBMS session management signaling.
A MCE is connected to one or more than one eNBs within the same MBSFN through M2 interface mainly for MBMS session management signaling and radio configuration signaling.
● User plane interface
M1 interface is a pure user plane interface.
A MBMS GW is connected to multiple eNBs through M1 interface for data distribution.
Reference points within EPC are not in the scope of this document. Please refer to TS 23.246 [8] for details.