Patent ID: 11950098
Assignee: AT&T MOBILITY II LLC
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 15:
16. A computer-readable storage medium comprising computer-executable instructions that, when executed by a processor of a user equipment, cause the processor to perform operations comprising:
enabling a voice-over-WI-FI (“VoWIFI”) service;
receiving hidden service set identifier (“SSID”) information;
registering with a core network via a radio access network;
monitoring a first signal strength of a first signal from the radio access network;
scanning for a second signal from a wireless local area network (“WLAN”), and when the second signal is found, measuring a second signal strength of the second signal;
determining whether the first signal strength is at or below a first threshold;
in response to determining that the first signal strength is at or below the first threshold, determining if a WLAN is available and is an untrusted WLAN;
in response to determining that the WLAN is potentially an untrusted WLAN, probing the untrusted WLAN with the hidden SSID information;
determining whether an untrusted WLAN access point associated with the untrusted WLAN responds to the hidden SSID information;
in response to determining that the untrusted WLAN access point responds to the hidden SSID information, generating an access request and sending the access request to the untrusted WLAN access point using the hidden SSID information;
receiving, via the untrusted WLAN access point, an authentication challenge from an evolved packet data gateway operating in the core network;
responding to the authentication challenge with an authentication response directed to the evolved packet data gateway; and
in response to the user equipment being authenticated to access the untrusted WLAN for registration with the core network, registering with the core network via the untrusted WLAN and the evolved packet data gateway.