US 11,659,389 B1
Architecture for providing cellular roaming support
Nassereddine Sabeur, Bellevue, WA (US); Joel Arends, Renton, WA (US); Saqib Badar, Bellevue, WA (US); Sabuhi Kiran Zaifuddin, Bellevue, WA (US); Raymond Thomas Ball, Seattle, WA (US); and Shujaur Rehman Mufti, Snoqualmie, WA (US)
Assigned to T-Mobile USA, Inc., Bellevue, WA (US)
Filed by T-Mobile USA, Inc., Bellevue, WA (US)
Filed on Apr. 28, 2021, as Appl. No. 17/302,242.
Int. Cl. H04W 12/06 (2021.01); H04W 4/14 (2009.01); H04W 60/00 (2009.01); H04W 8/06 (2009.01)
CPC H04W 12/06 (2013.01) [H04W 4/14 (2013.01); H04W 8/06 (2013.01); H04W 60/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A computer-implemented method comprising:
receiving at a proxy-call session control function (P-CSCF) of a visiting network, a registration request from a user equipment (UE);
sending the registration request to interrogating call session control function (I-CSCF) and a serving-call session control function (S-CSCF);
generating, at the I-CSCF, a user authentication request, the user authentication request in a first format assorted with the visiting network;
sending the user authorization request to an international serials data system (ISDS);
sending, from the ISDS, a user authentication answer to the I-CSCF, the user authentication answer in the first format;
sending, from the ISDS, authentication data to a home location register (HLR), the authentication data in a second format associated with a home network of the UE;
receiving, at the ISDS, location data from the HLR, the location data in the second format;
sending, from the S-CSCF, a subscriber authentication request to the ISDS, the subscriber authentication request in the first format;
sending, from the ISDS, a subscriber authentication answer to the C-CSCF, the subscriber authentication answer in the first format; and
registering the UE with an IP Multimedia Subsystem (IMS).