Voice call resumption on a legacy network

• US 9,338,718 B2
• Filed: 05/08/2013
• Issued: 05/10/2016
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Khay-Ibbat, Samy, Vangala, Sarma V., Vallath, Sreevalsan, Tabet, Tarik
• Primary Examiner(s): Chriss, Andrew
• Assistant Examiner(s): MAK, PETER K
• Application Number:
  US13/890,026
• Publication Number:
  US 20140269624A1
• Time in Patent Office: 1,098 Days
• Field of Search: 370/252, 370/280, 370/352, 370/401
• US Class Current: 1/1
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A method for resuming a voice call on a legacy network is provided. The method can include a wireless communication device establishing a voice call with a remote device over a first cellular network; determining that a connection quality of the first cellular network has dropped below a threshold connection quality; sending a notification that the wireless communication device is releasing the voice call to transition to a legacy cellular network and will resume the voice call on the legacy cellular network; releasing the voice call on the first cellular network; transitioning to the legacy cellular network; establishing a second voice call with the remote device on the legacy cellular network; and using the second voice call to resume the voice call with the remote device.

Claims

1. A method for resuming a voice call on a legacy cellular network, the method comprising a wireless communication device:

establishing the voice call with a remote device over a first connection between the wireless communication device and the remote device via a Long Term Evolution (LTE) network, the voice call being serviced as a voice over LTE (VoLTE) call on the LTE network;

determining that a connection quality of the LTE network has dropped below a threshold connection quality;

sending a notification that the wireless communication device is releasing the voice call from the LTE network to transition to a legacy cellular network and to resume the voice call on the legacy cellular network;

releasing the voice call on the LTE network by terminating the voice call on the LTE network at an Internet Protocol Multimedia Subsystem (IMS) layer;

providing an indication via a user interface of the wireless communication device that the voice call is ongoing during a period between releasing the voice call on the LTE network and establishing a second connection with the remote device via the legacy cellular network;

transitioning to the legacy cellular network in response to the connection quality of the LTE network dropping below the threshold connection quality, the legacy cellular network having a circuit switched domain for supporting voice calls;

establishing the voice call with the remote device over the second connection via the legacy cellular network, the second connection being provided via the circuit switched domain of the legacy cellular network; and

using the second connection to resume the voice call with the remote device.

2. The method of claim 1, wherein establishing the second connection and using the second connection to resume the voice call with the remote device are performed automatically after transitioning to the legacy cellular network.

3. The method of claim 1, wherein establishing the second connection and using the second connection to resume the voice call with the remote device is transparent to the user interface of the wireless communication device.

4. The method of claim 1, wherein sending the notification comprises sending a real-time transport protocol (RTP) packet to the remote device.

5. The method of claim 1, wherein sending the notification comprises sending the notification to a network entity, the network entity being configured to provide notification to the remote device that the wireless communication device is releasing the voice call to transition to the legacy cellular network and to resume the voice call on the legacy cellular network.

6. The method of claim 1, further comprising the wireless communication device confirming that the remote device supports a background call resumption feature when establishing the voice call via the LTE network.

7. The method of claim 1, further comprising the wireless communication device:

performing a measurement of the legacy cellular network while engaged in the voice call on the LTE network; and

selecting to transition to the legacy cellular network based at least in part on the measurement of the legacy cellular network.

8. The method as in claim 1, wherein the indication is displayed on a display associated with the user interface of the wireless communication device.

9. The method as in claim 1, wherein the indication is an audible indication.

10. A wireless communication device comprising:

at least one transceiver, the at least one transceiver configured to transmit data and receive data via a first cellular network and a legacy cellular network; and

processing circuitry coupled to the at least one transceiver, the processing circuitry configured to control the wireless communication device to at least;

establish a voice call with a remote device over a first connection between the wireless communication device and the remote device via the first cellular network, the voice call being serviced via a packet switched domain of the first cellular network;

determine that a connection quality of the first cellular network has dropped below a threshold connection quality;

send a notification via a first session initiation protocol (SIP) message to the remote device that the wireless communication device is releasing the voice call to transition to the legacy cellular network and to resume the voice call on the legacy cellular network;

receive an acknowledgement via a second SIP message from the remote device;

release the voice call on the first cellular network;

provide an indication via a user interface of the wireless communication device that the voice call is ongoing during a period between releasing the voice call on the first cellular network and establishing a second connection with the remote device via the legacy cellular network;

transition to the legacy cellular network in response to the connection quality of the first cellular network dropping below the threshold connection quality, the legacy cellular network having a circuit switched domain for supporting voice calls;

establish the voice call with the remote device over the second connection via the legacy cellular network, the second connection being provided via the circuit switched domain of the legacy cellular network; and

use the second connection to resume the voice call with the remote device.

11. The wireless communication device of claim 10, wherein the processing circuitry is configured to control the wireless communication device to establish the second connection and use the second connection to resume the voice call with the remote device automatically after transitioning to the legacy cellular network.

12. The wireless communication device of claim 10, wherein establishment of the second connection and usage of the second connection to resume the voice call with the remote device is transparent to the user interface of the wireless communication device.

13. The wireless communication device of claim 10, wherein the processing circuitry is further configured to control the wireless communication device to provide an indication via the user interface of the wireless communication device that the voice call is ongoing during a period between releasing the voice call on the first cellular network and establishing the voice call on the legacy cellular network.

14. The wireless communication device of claim 10, wherein the processing circuitry is configured to control the wireless communication device to send the notification to the remote device.

15. The wireless communication device of claim 10, wherein the processing circuitry is configured to control the wireless communication device to send the notification to a network entity, the network entity being configured to provide notification to the remote device that the wireless communication device is releasing the voice call to transition to the legacy cellular network and to resume the voice call on the legacy cellular network.

16. The wireless communication device of claim 10, wherein the processing circuitry is further configured to use unused carrier aggregation receiver capability to perform measurements and/or to start pre-registration procedures on the legacy cellular network while the voice call with the remote device is ongoing on the first cellular network.

17. A non-transitory computer-readable storage medium, storing a set of computer program instructions for resuming a voice call on a legacy cellular network, that when executed by one or more processors of a wireless communication device, cause the wireless communication device to:

establish the voice call with a remote device over a first connection between the wireless communication device and a first cellular network, the voice call being serviced via a packet switched domain of the first cellular network;

determine that a connection quality of the first cellular network has dropped below a threshold connection quality;

send a notification via a first session initiation protocol (SIP) message to the remote device that the wireless communication device is releasing the voice call from the first cellular network to transition to a legacy cellular network and to resume the voice call on the legacy cellular network;

receive an acknowledgement via a second SIP message from the remote device;

release the voice call from the first cellular network;

provide an indication via a user interface of the wireless communication device that the voice call is ongoing during a period between releasing the voice call on the first cellular network and establishing a second connection with the remote device via the legacy cellular network;

transition to the legacy cellular network in response to the connection quality of the first cellular network dropping below the threshold connection quality, the legacy cellular network having a circuit switched domain for supporting voice calls;

establish the voice call over the second connection with the remote device via the legacy cellular network, the second connection being provided via the circuit switched domain of the legacy cellular network; and

use the second connection to resume the voice call with the remote device.

18. The non-transitory computer-readable storage medium of claim 17, wherein establishing the second connection and using the second connection to resume the voice call with the remote device is transparent to the user interface of the wireless communication device.

19. The non-transitory computer-readable storage medium of claim 17, further comprising program code for providing an indication via the user interface of the wireless communication device that the voice call is ongoing during a period between releasing the voice call on the first cellular network and establishing the second connection on the legacy cellular network.

20. The non-transitory computer-readable storage medium of claim 17, further comprising program code for confirming that the remote device supports a background call resumption feature when establishing the voice call via the first cellular network.

21. The non-transitory computer-readable storage medium of claim 17, wherein the first cellular network utilizes a Long Term Evolution (LTE) radio access technology, the voice call being serviced as a voice over LTE (VoLTE) call on the first cellular network.

22. A method for resuming a voice call following transition of a remote wireless communication device from a first cellular network to a legacy cellular network, the method comprising a communication device:

establishing the voice call with the remote wireless communication device;

receiving a notification that the remote wireless communication device is releasing the voice call to transition from a first cellular network to the legacy cellular network and to resume the voice call on the legacy cellular network;

releasing the voice call in response to receipt of the notification;

providing an indication via a user interface of the communication device that the voice call is ongoing during a period between releasing the voice call from the first cellular network and receiving the voice call from the remote wireless communication device after the remote wireless communication device has transitioned to the legacy cellular network;

receiving the voice call from the remote wireless communication device after the remote wireless communication device has transitioned to the legacy cellular network; and

using the legacy cellular network to resume the voice call with the remote wireless communication device,

wherein the remote wireless communication device terminates the voice call with the first cellular network at an Internet Protocol Multimedia Subsystem (IMS) layer.

23. The method of claim 22, further comprising the communication device:

confirming that the remote wireless communication device supports a background call resumption feature when establishing the voice call.

24. The method of claim 22, wherein receiving the notification comprises receiving a notification sent by the remote wireless communication device.

25. The method of claim 22, wherein receiving the notification comprises receiving a notification provided by a network entity.