US 9,813,960 B2
Wi-Fi calling using SIP-IMS handset and evolved packet data gateway
Ming Shan Kwok, Seattle, WA (US); Adnan Rahat, Newcastle, WA (US); Gunjan Nimbavikar, Bellevue, WA (US); and Nayla Hamade, Bellevue, WA (US)
Assigned to T-Mobile USA, Inc., Bellevue, WA (US)
Filed by T-Mobile USA, Inc., Bellevue, WA (US)
Filed on May 29, 2015, as Appl. No. 14/726,279.
Claims priority of provisional application 62/004,861, filed on May 29, 2014.
Prior Publication US 2015/0350983 A1, Dec. 3, 2015
Int. Cl. H04W 36/14 (2009.01); H04L 29/06 (2006.01); H04W 24/10 (2009.01); H04W 36/00 (2009.01); H04W 36/24 (2009.01)
CPC H04W 36/14 (2013.01) [H04L 65/1006 (2013.01); H04L 65/1016 (2013.01); H04L 65/1069 (2013.01); H04L 65/80 (2013.01); H04W 24/10 (2013.01); H04W 36/0022 (2013.01); H04W 36/24 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method, comprising:
determining, by a mobile device, whether any Long-Term Evolution (LTE) coverage is available;
determining, by the mobile device, whether data roaming is available;
determining, by the mobile device, whether a visited public land mobile network (VPLMN) is available;
determining, by the mobile device, whether a domain name server (DNS) query to a first evolved packet data gateway (ePDG) is successful;
connecting the mobile device to the first ePDG responsive to a determination that LTE coverage is available, a determination that data roaming is available, a determination that a VPLMN is available, and a determination that the DNS query to the first ePDG is successful;
routing Session Initiation Protocol-Internet Protocol (IP) Multimedia Subsystem (SIP-IMS) traffic between the mobile device and a packet data network (PDN) gateway through via a Wi-Fi access point and the first ePDG while the mobile device is connected to the first ePDG, and routing over-the-top (OTT) applications traffic to an Internet service provider (ISP) network via the Wi-Fi access point while the mobile device is connected to the first ePDG; and
connecting the mobile device to a second ePDG responsive to a determination that no data roaming is available or a determination that no LTE coverage is available.