BSFN Propagation Joint CIR between BS sites and UE Delay Base station 2 Base station 1, 2, 3 & 4 Propagation Delay Base station 3 Propagation Delay Propagation Delay Base station 4 Propagation Delay Figure 9.18 MBMS VS. MBSFN IMS, Services and Applications (e.g. Internet) Content Provider, Multicast Broadcast Source Content Provider/ Gn/Gp UTRAN Multicast BM -SC Broadcast Source lu/Gb BM-SC GERAN Other PLMN Figure 9.19 Reference architecture to support MBMS in GERAN and UTRAN. Reproduced with permission from C 2009 3GPP [29] 9.12.2.7.2 MBMS Architecture The MBMS architecture as it applies to GERAN and UTRAN is shown in Figure 9.19. A new functional entity called Broadcast Multicast Service Center (BM-SC) is added to support MBMS. BMCS provides a set of functions for MBMS User Services which can be supported from the same or different physical network elements. The BM-SC indicates session start and stop to the GGSN including session attributes like QoS and MBMS service area. The BM-SC initiates the deactivation of a user specific MBMS bearer service when the MBMS user service is terminated. The BM-SC provides functions for MBMS user service provisioning and delivery. It may serve as an entry point for content provider MBMS transmissions, used to authorize and initiate MBMS Bearer Services within the PLMN (public land mobile network) and can be used to schedule and deliver MBMS transmissions [29]. Additionally, two reference points namely Gmb and Mz are included to support MBMS. Gmb allow the signaling to take place between GGSN and BM-SC. This represents the network side boundary of the MBMS Bearer Service from a control plane perspective. This includes user specific Gmb signaling and MBMS bearer service specific signaling. Mz is the roaming variant of the Gmb reference point with the same functionality as described under Gmb. The reference architecture of eMBMS (evolved MBMS) with EPS defined in Rel-9 is shown in Figure 9.20. The functionality of BM-SC remains the same, however, new reference points have been add