Granted Patent B2

US 12,739,287 · App. 18/553,726 · Granted Sep 15, 2026

Inventors: Shuhong Wang (Shanghai, CN); Bing Leng (Shanghai, CN); Jing Zhou (Shanghai, CN); Jian Li (Shanghai, CN); Xuefeng Chen (Shanghai, CN); Yan Wang (Shanghai, CN); Hao Zhang (Shanghai, CN)

Assignee: QUALCOMM Incorporated

H04L65/1016H04L65/1069H04W76/18

Abstract

Claims (53)

1 . A method of wireless communication performed by a user equipment (UE), comprising:

attempting a mobile originated packet switched call across a packet switched network with a first transmission control protocol (TCP) connection of an Internet Protocol multimedia subsystem (IMS) session;

performing a silent redial of the mobile originated packet switched call via a circuit switched network, in response to a failure of the mobile originated packet switched call;

reconnecting to the packet switched network without re-establishing the first TCP connection after terminating the circuit switched network call;

transmitting a keep alive message over the packet switched network in accordance with reconnecting to the packet switched network;

transmitting a first TCP message to a first proxy call session control function (P-CSCF) to attempt to re-establish the first TCP connection with the first P-CSCF, in response to a first timer expiring before receiving a response to the keep alive message;

transmitting a second TCP message to a second P-CSCF in response to a second timer expiring before receiving a response to the first TCP message, the second TCP message attempting to re-establish the first TCP connection with the second P-CSCF and attempting to register with the second P-CSCF; and

releasing the IMS session and re-establishing the IMS session in response to a third timer expiring before receiving a response to the second TCP message.

2 . The method of claim 1 , further comprising:

acquiring a new IP address from the IMS session after re-establishing the IMS session; and

acquiring an address of a third P-CSCF from the IMS session, after re-establishing the IMS session.

3 . The method of claim 2 , wherein the IMS session is a packet data network (PDN) session.

4 . The method of claim 2 , wherein the IMS session is a protocol data unit (PDU) session.

5 . The method of claim 1 , wherein the keep alive message syncs a TCP connection status between the UE and the first P-CSCF.

6 . The method of claim 1 , wherein the packet switched network is a new radio (NR) network.

7 . The method of claim 1 , wherein the packet switched network is a long-term evolution network (LTE).

8 . An apparatus for wireless communication by a user equipment (UE), comprising:

at least one memory;

at least one processor coupled to the at least one memory; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus:

to attempt a mobile originated voice over Internet Protocol (VoIP) call across a packet switched network with a first transmission control protocol (TCP) connection of an Internet Protocol multimedia subsystem (IMS) session;

to perform a silent redial of the mobile originated packet switched call via a circuit switched network, in response to a failure of the mobile originated packet switched call;

to reconnect to the packet switched network without re-establishing the first TCP connection after terminating the circuit switched network call;

to transmit a keep alive message over the packet switched network in accordance with reconnecting to the packet switched network;

to transmit a first TCP message to a first proxy call session control function (P-CSCF) to attempt to re-establish the first TCP connection with the first P-CSCF, in response to a first timer expiring before receiving a response to the keep alive message;

to transmit a second TCP message to a second P-CSCF in response to a second timer expiring before receiving a response to the first TCP message, the second TCP message attempting to re-establish the first TCP connection with the second P-CSCF and attempting to register with the second P-CSCF; and

to release the IMS session and re-establish the IMS session in response to timeout for all assigned P-CSCFs.

9 . The apparatus of claim 8 , wherein execution of the instructions further cause the apparatus:

to acquire a new IP address from the IMS session after re-establishing the IMS session; and

to acquire an address of a third P-CSCF from the IMS session, after re-establishing the IMS session.

10 . The apparatus of claim 9 , wherein the IMS session is a packet data network (PDN) session.

11 . The apparatus of claim 9 , wherein the IMS session is a protocol data unit (PDU) session.

12 . The apparatus of claim 8 , wherein the keep alive message syncs a TCP connection status between the UE and the first P-CSCF.

13 . The apparatus of claim 8 , wherein the packet switched network is a new radio (NR) network.

14 . The apparatus of claim 8 , wherein the packet switched network is a long-term evolution (LTE) network.

15 . The apparatus of claim 8 , wherein the apparatus further comprises:

a voice over Internet Protocol (VoIP) management module configured to communicate with a base station, the packet switched network, and the circuit switched network; and

a silent redial timer.

16 . An apparatus for wireless communication by a user equipment (UE), comprising:

means for attempting a mobile originated packet switched call across a packet switched network with a first transmission control protocol (TCP) connection of an Internet Protocol multimedia subsystem (IMS) session;

means for performing a silent redial of the mobile originated packet switched call via a circuit switched network, in response to a failure of the mobile originated packet switched call;

means for reconnecting to the packet switched network without re-establishing the first TCP connection after terminating the circuit switched network call;

means for transmitting a keep alive message over the packet switched network in accordance with reconnecting to the packet switched network;

means for transmitting a first TCP message to a first proxy call session control function (P-CSCF) to attempt to re-establish the first TCP connection with the first P-CSCF, in response to a first timer expiring before receiving a response to the keep alive message;

means for transmitting a second TCP message to a second P-CSCF in response to a second timer expiring before receiving a response to the first TCP message, the second TCP message attempting to re-establish the first TCP connection with the second P-CSCF and attempting to register with the second P-CSCF; and

means for releasing the IMS session and re-establish the IMS session in response to timeout for all assigned P-CSCFs.

17 . The apparatus of claim 16 , further comprising:

means for acquiring a new IP address from the IMS session after re-establishing the IMS session; and

means for acquiring an address of a third P-CSCF from the IMS session, after re-establishing the IMS session.

18 . The apparatus of claim 17 , wherein the IMS session is a packet data network (PDN) session.

19 . The apparatus of claim 17 , wherein the IMS session is a protocol data unit (PDU) session.

20 . The apparatus of claim 16 , wherein the means for transmitting a keep alive message syncs a TCP connection status between the UE and the first P-CSCF.

21 . The apparatus of claim 16 , wherein the packet switched network is a new radio (NR) network.

Assignments (1)

Continuity (1)

References Cited (11)