Rogier Nöldus, Martien Huijsmans, Anders Ryde and Jonas Falkenå
How service developers can focus on adding new value to IMS telephony for both users and operators – without having to apply basic SIP. Multimedia communication networks based on IMS and standards for multimedia telephony (MMTel) provide support for voice-over-LTE (VoLTE) and a basic set of telephony services. The combination of IMS and multimedia telephony (MMTel) make multimedia functions possible, so that users can add or remove services and callers during an ongoing communication session – a user can start a communication session with messaging, complement it with voice or video, add or remove participants, send files, share pictures and more.
MMTel is the IMS standard that facilitates telephony, and it includes a defined set of basic services and supplementary services. Value-added services augment these basic and supplementary services, and must be clearly separated from the telephony when they are applied to MMTel. The interface needed between the VAS, and the IMS/MMTel architecture needs to be well defined.
3GPP has specified, and continues to enhance, an extensive set of telephony services for the next-generation mobile network, including advanced features such as VoLTE, voice-call continuity (VCC), session continuity and ICS. Specific functional entities in the IMS network architecture are standardized and implemented in the Ericsson MMTel architecture.
The separation of value-added services from MMTel is achieved through a services-specific northbound protocol exposure from MTAS. This approach has two advantages. First, functionality can be added to MMTel’s extensive set of basic telephony and video services, combined with advanced services such as VCC. Second, service developers can concentrate on adding value to telephony rather than on controlling it.