IP Library › Granted Patent US 12,568,351
Granted Patent B2
US 12,568,351 · App. 18/500,731 · Granted Mar 3, 2026

Systems and methods for bypassing service continuity gateways based on roaming

Inventors: John Cao Vinh Nguyen (Trophy Club, TX); Bibi M. Hakimzadeh (Fort Worth, TX); Toby Varughese John (Murphy, TX); Danysel Barthelme (Frisco, TX)
Assignee: Verizon Patent and Licensing Inc.
H04W8/082
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Quick Facts
Patent No.
US 12,568,351
App. No.
18/500,731
Granted
Mar 3, 2026
Kind
B2
Abstract

In some implementations, a call session control function (CSCF) may identify information associated with a user equipment (UE). The CSCF may determine, based on the information, whether the UE is roaming in a circuit switched mobility network. The CSCF may transmit signaling associated with delivering a call to the UE, wherein the signaling bypasses a service continuity gateway (SCG) on a call delivery path when the UE is not roaming in the circuit switched mobility network and the signaling traverses the SCG on the call delivery path when the UE is roaming in the circuit switched mobility network.

Claims (32)

1 . A method, comprising:

identifying, by a call session control function (CSCF), information associated with a user equipment (UE);

determining, by the CSCF and based on the information, whether the UE is roaming in a circuit switched mobility network; and

transmitting, by the CSCF, signaling associated with delivering a call to the UE, wherein the signaling bypasses a service continuity gateway (SCG) on a call delivery path when the UE is not roaming in the circuit switched mobility network and the signaling traverses the SCG on the call delivery path when the UE is roaming in the circuit switched mobility network.

2 . The method of claim 1 , wherein the information indicates an Internet Protocol multimedia subsystem (IMS) registration status associated with the UE.

3 . The method of claim 1 , wherein the information indicates a location associated with the UE.

4 . The method of claim 1 , wherein the CSCF is a serving CSCF (S-CSCF).

5 . The method of claim 1 , wherein the circuit switched mobility network is a global system for mobile communication (GSM) network.

6 . The method of claim 1 , wherein the circuit switched mobility network is a code-division multiple access (CDMA) network.

7 . The method of claim 1 , wherein the UE is associated with a terminating network.

8 . A method, comprising:

receiving, by a call session control function (CSCF) and from a telephone application server (TAS), a flag indicating whether a user equipment (UE) is roaming in a circuit switched mobility network; and

transmitting, by the CSCF, signaling associated with delivering a call to the UE, wherein the signaling bypasses a service continuity gateway (SCG) on a call delivery path when the UE is not roaming in the circuit switched mobility network and the signaling traverses the SCG on the call delivery path when the UE is roaming in the circuit switched mobility network.

9 . The method of claim 8 , wherein the flag is set based on a subscriber profile in a home subscriber service (HSS), and roaming is activated or deactivated in the subscriber profile based on a code.

10 . The method of claim 8 , wherein the UE is set to not roaming as a default setting, and the SCG is used in the call delivery path based on the UE roaming in the circuit switched mobility network.

11 . The method of claim 8 , wherein the flag is received in a session initiation protocol (SIP) invite message.

12 . The method of claim 8 , wherein the circuit switched mobility network is a global system for mobile communication (GSM) network.

13 . The method of claim 8 , wherein the circuit switched mobility network is a code-division multiple access (CDMA) network.

14 . A device, comprising:

one or more processors configured to:

identify information associated with a user equipment (UE);

determine, based on the information, that the UE is not roaming in a global system for mobile communication (GSM) network; and

transmit signaling associated with delivering a call to the UE, wherein the signaling bypasses a service continuity gateway (SCG) on a call delivery path based on the UE not roaming in the GSM network.

15 . The device of claim 14 , wherein the information indicates an Internet Protocol multimedia subsystem (IMS) registration status associated with the UE.

16 . The device of claim 14 , wherein the information indicates a location associated with the UE.

17 . The device of claim 14 , wherein the one or more processors are further configured to:

determine that the UE is roaming in the GSM network; and

transmit signaling that traverses the SCG on the call delivery path based on the UE roaming in the GSM network.

18 . The device of claim 14 , wherein:

the device is a serving call session control function (S-CSCF); and

the UE is associated with a terminating network.

19 . The device of claim 14 , wherein the UE is set to not roaming as a default setting.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 3, 2023
From: NGUYEN, JOHN CAO VINH; HAKIMZADEH, BIBI M.; JOHN, TOBY VARUGHESE; BARTHELME, DANYSEL
To: VERIZON PATENT AND LICENSING INC.
Reel/Frame 065455/0976 →
Continuity (1)
Related Publication 20250150804A1 · May 8, 2025
References Cited (1)
US 20240259913A1 · Haustein · 2024 [cited by examiner]