IMS - MBMS Integration: Functional Analysis & Architectural Design

The introduction of IMS into a network operator´s core network enables substantial possibilities for broadcast/multicast applications. Besides the radio efficient MBMS, other access technologies e.g. DVB-H, Wi-Fi (802.11) etc., can also serve as a delivery platform with IMS as the controlling entity. Currently, IMS only supports unicast transmission, this paper explores the functional and architectural implications of a broadcast/multicast enabled IMS. MBMS is selected as the broadcast/multicast delivery technology. A functional analysis is carried out to identify the main features offered/supported by MBMS, including an interface analysis. Two integration approaches are adopted; network architectures and network entity designs are proposed for both. In the first approach IMS applications can use MBMS and the BM-SC is left unchanged; this IMS-MBMS integration is appropriate for 3GPP R7/R8 architecture, but it fails to support heterogeneous delivery technologies. The second approach considers the functions of the BM-SC to be distributed across the various IMS entities and is more appropriate to the long-term vision of the 3GPP SAE/LTE architecture. This work is carried out as part of EU-IST project C-MOBILE (IST-2005-27423).