Patent ID: 11997146

Abstract:
Internet Protocol Multimedia Subsystem (IMS) restoration for a user equipment (UE) may be automatically triggered in response to the UE receiving a message waiting indicator (MWI) or a text message via a fallback protocol that is used as a backup for a primary protocol for delivering the MWI or the text message. For example, if a UE receives a MWI via Non-Access Stratum (NAS) protocol (where NAS protocol serves as a fallback protocol for Session Initiation Protocol (SIP) to deliver the MWI when IMS-based services are unavailable), an IMS restoration procedure may be triggered for the UE where the UE sends a request to register for one or more services of a telecommunication service provider in an effort to restore IMS-based services for the UE, thereby allowing calls to be subsequently established with the UE.