CPC H04W 4/90 (2018.02) [H04L 65/1016 (2013.01); H04L 65/1069 (2013.01); H04L 65/1073 (2013.01); H04L 65/1104 (2022.05); H04W 60/00 (2013.01); H04W 76/50 (2018.02); H04L 65/1045 (2022.05); H04M 3/5116 (2013.01); H04W 8/20 (2013.01); H04W 12/06 (2013.01); H04W 12/72 (2021.01); H04W 80/10 (2013.01); H04W 92/02 (2013.01)] | 20 Claims |
1. A method of operating a user equipment (“UE”) to handle an internet protocol multimedia subsystem (“IMS”) emergency call, the method comprising:
sending a session initiation protocol (“SIP”) REGISTER request relating to an emergency registration to a proxy call session control function (“P-CSCF”) of an IMS network;
responsive to sending the SIP REGISTER request, receiving a 200 OK response from the P-CSCF including at least one of:
a telephone (“TEL”) uniform resource identifier (“URI”) based on one or more identifiers that includes a mobile subscriber integrated services digital network number (“MSISDN”) and does not include an international mobile subscriber identity (“IMSI”); and
a SIP URI for the UE based on a mobile network code (“MNC”), a mobile country code (“MCC”), and global E.164 number conversion of the MSISDN; and
responsive to receiving the response, performing an action based on the response.
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