METHOD AND APPARATUSES FOR MAKING USE OF VIRTUAL IMS SUBSCRIPTIONS COUPLED WITH THE IDENTITY OF A NON SIP COMPLIANT TERMINAL FOR NON-REGISTERED SUBSCRIBERS

摘要

The present invention relates to an overlay system between a GSM and IMS network, making use of virtual IMS subscriptions, which are temporary coupled with the identity of a non SIP compliant terminal, when the non SIP compliant terminal makes a call, is called or invokes an IMS service during the call, for the purpose of initiating a SIP session providing an IMS service to the terminal.