Combining Circuit Switched (CS) bearers with IP Multimeida Subsystem (IMS)
The present document investigates architectural requirements and architectural alternatives for using existing CS bearers in association with an IM session. The document considers overall requirements, architectural requirements, considerations for evaluation of potential architectural solutions and proposed alternative architectures.
The Feasibility Study covers different solutions for offering existing IMS simultaneous services (real-time media + non-real-time media) also in GERAN, where conversational PS spectrum efficiency is too low.
The target is to seek for an architectural solution that is completely transparent for the end-user, and is easily interoperable with existing IMS services&networks that don’t use this solution.
The solutions studied within the Feasibility Study are not necessarily restricted by existing service requirements. However, if an alternative is chosen to be included in specifications, it must be cross-checked with existing service requirements.