Method, apparatuses and program product for controlling IMS services when user is roaming in CS domain

摘要

The present invention relates to a method, network element, network arrangement, system and computer program product for controlling services of an internet protocol multimedia subsystem (IMS) 5 in a network when a user equipment (UE) 1 is roaming in the circuit switched (CS) domain 3 without having internet protocol (IP) connectivity. In this case, the service control must rely on CS transmission techniques such as unstructured supplementary service data (USSD). The present invention enables to improve a routing of USSD messages between the UE 1 and an IMS circuit switched control function (ICCF) 11.