Implicit emergency registration set

An apparatus, comprising:

• a processor configured to initiate an identifier selection procedure,
• wherein the processor is configured to identify whether a user has a dedicated emergency telephone uniform resource identifier, and, when the user has the dedicated emergency telephone uniform resource identifier, the processor is configured to select the dedicated emergency telephone uniform resource identifier,
• wherein the processor is further configured to identify, when the user does not have the dedicated emergency telephone uniform resource identifier, whether the user's internet protocol multimedia private identity is known,
• wherein the processor is additionally configured to identify, when the user's internet protocol multimedia private identity is known, whether the user's internet protocol multimedia private identity has a non-shared telephone uniform resource identifier, and the processor is configured to select the non-shared telephone uniform resource identifier when the user's internet protocol multimedia private identity has the non-shared telephone uniform resource identifier, otherwise to select a telephone uniform resource identifier of the user's internet protocol multimedia private identity, and
• wherein the processor is also configured to identify, when the user's internet protocol multimedia private identity is not known, whether a shared telephone uniform resource identifier is available, and the processor is configured to select the shared telephone uniform resource identifier when the shared telephone uniform resource identifier is available, otherwise to select a telephone uniform resource identifier from a non-shared set.

An apparatus, comprising:

• initiation means for initiating an identifier selection procedure;
• first identification means for identifying whether a user has a dedicated emergency telephone uniform resource identifier, and, when the user has the dedicated emergency telephone uniform resource identifier, for selecting the dedicated emergency telephone uniform resource identifier;
• second identification means for identifying, when the user does not have the dedicated emergency telephone uniform resource identifier, whether the user's internet protocol multimedia private identity is known;
• third identification means identifying, when the user's internet protocol multimedia private identity is known, whether the user's internet protocol multimedia private identity has a non-shared telephone uniform resource identifier, and for selecting the non-shared telephone uniform resource identifier when the user's internet protocol multimedia private identity has the non-shared telephone uniform resource identifier, otherwise selecting a telephone uniform resource identifier of the user's internet protocol multimedia private identity;
• and
• fourth identification means for identifying, when the user's internet protocol multimedia private identity is not known, whether a shared telephone uniform resource identifier is available, and for selecting the shared telephone uniform resource identifier when the shared telephone uniform resource identifier is available, otherwise selecting a telephone uniform resource identifier from a non-shared set.

A non-transitory computer readable medium encoding instructions for performing a method when executed on a hardware device, the method comprising:

• initiating an identifier selection procedure;
• identifying whether a user has a dedicated emergency telephone uniform resource identifier, and, when the user has the dedicated emergency telephone uniform resource identifier, selecting the dedicated emergency telephone uniform resource identifier;
• identifying, when the user does not have the dedicated emergency telephone uniform resource identifier, whether the user's internet protocol multimedia private identity is known;
• identifying, when the user's internet protocol multimedia private identity is known, whether the user's internet protocol multimedia private identity has a non-shared telephone uniform resource identifier, and selecting the non-shared telephone uniform resource identifier when the user's internet protocol multimedia private identity has the non-shared telephone uniform resource identifier, otherwise selecting a telephone uniform resource identifier of the user's internet protocol multimedia private identity;
• and
• identifying, when the user's internet protocol multimedia private identity is not known, whether a shared telephone uniform resource identifier is available, and selecting the shared telephone uniform resource identifier when the shared telephone uniform resource identifier is available, otherwise selecting a telephone uniform resource identifier from a non-shared set.