Preempt single radio voice call continuity by moving to voice over WiFi to improve voice/video call quality

Patent metadata

Field	Value
Publication number	US-11317333-B2
Application number	US-202016870686-A
Country	US
Kind code	B2
Filing date	May 8, 2020
Priority date	May 8, 2020
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A configuration is disclosed to enable a UE to preempt SRVCC by triggering a handover to a Wi-Fi network. The apparatus determines whether a Wi-Fi cell is viable as a first target cell, from a plurality of target cells, serving the UE to continue the active transmission on the Wi-Fi cell. The apparatus extends a TTT timer length based at least in part on the determination that the Wi-Fi cell is viable as the target cell serving the UE to continue the active transmission on the Wi-Fi cell. The apparatus initiates a handover to the Wi-Fi cell from the first network prior to the expiration of a TTT timer and prior to the first network initiating a handover to a second target cell, from the plurality of target cells, on a second network.

First claim

What is claimed is:

1. A method of wireless communication at a user equipment (UE), comprising:
determining whether a Wi-Fi cell is viable as a first target cell, from a plurality of target cells, serving the UE to continue an active transmission on the Wi-Fi cell;
extending a time-to-trigger (TTT) timer length based at least in part on the determination that the Wi-Fi cell is viable as the target cell serving the UE to continue the active transmission on the Wi-Fi cell; and
initiating a handover to the Wi-Fi cell from the first network prior to the expiration of a TTT timer and prior to the first network initiating a handover to a second target cell, from the plurality of target cells, on a second network.

2. The method of claim 1 , further comprising:
receiving, from a base station of the first network, handover thresholds for the handover between the first network and the second network.

3. The method of claim 1 , wherein the Wi-Fi cell is viable as the target cell serving the UE to continue the active transmission on the Wi-Fi cell based on at least a signal strength of the Wi-Fi cell.

4. The method of claim 1 , wherein the determining whether the Wi-Fi cell is viable as the target cell occurs prior to the second target cell on the second network meeting handover thresholds.

5. The method of claim 4 , wherein the initiating the handover to the Wi-Fi cell from the first network occurs if a signal strength of the Wi-Fi cell is greater than a signal strength of the first network.

6. The method of claim 1 , wherein the extending the TTT timer length delays a transmission of a measurement report from the UE to a base station, wherein the measurement report comprises signal strengths of the first network and the second network in preparation of the handover from the first network to the second network.

7. The method of claim 6 , wherein the delay in the transmission of the measurement report allows for the initiation of the handover to the Wi-Fi cell from the first network.

8. The method of claim 7 , wherein the measurement report is not transmitted at the expiration of the TTT timer if the handover to the Wi-Fi cell is completed.

9. The method of claim 7 , wherein the measurement report is not transmitted at the expiration of the TTT time if the first network does not have the active transmission.

10. The method of claim 1 , further comprising:
determining whether a signal strength of the second target cell is greater than a signal strength of the active transmission on the first network, such that the first network is preparing to initiate the handover to the second target cell.

11. An apparatus for wireless communication at a user equipment (UE), comprising:
a memory; and
at least one processor coupled to the memory and configured to:
determine whether a Wi-Fi cell is viable as a first target cell, from a plurality of target cells, serving the UE to continue an active transmission on the Wi-Fi cell;
extend a time-to-trigger (TTT) timer length based at least in part on the determination that the Wi-Fi cell is viable as the target cell serving the UE to continue the active transmission on the Wi-Fi cell; and
initiate a handover to the Wi-Fi cell from the first network prior to the expiration of a TTT timer and prior to the first network initiating a handover to a second target cell, from the plurality of target cells, on a second network.

12. The apparatus of claim 11 , wherein the at least one processor is further configured to:
receive, from a base station of the first network, handover thresholds for the handover between the first network and the second network.

13. The apparatus of claim 11 , wherein the Wi-Fi cell is viable as the target cell serving the UE to continue the active transmission on the Wi-Fi cell based on at least a signal strength of the Wi-Fi cell.

14. The apparatus of claim 11 , wherein the at least one processor is configured to determine whether the Wi-Fi cell is viable as the target cell prior to the second target cell on the second network meeting handover thresholds.

15. The apparatus of claim 14 , wherein the at least one processor is configured initiate the handover to the Wi-Fi cell from the first network if a signal strength of the Wi-Fi cell is greater than a signal strength of the first network.

16. The apparatus of claim 11 , wherein the at least one processor is configured to extend the TTT timer length to delay a transmission of a measurement report from the UE to a base station, wherein the measurement report comprises signal strengths of the first network and the second network in preparation of the handover from the first network to the second network.

17. The apparatus of claim 16 , wherein the delay in the transmission of the measurement report allows for the initiation of the handover to the Wi-Fi cell from the first network.

18. The apparatus of claim 17 , wherein the measurement report is not transmitted at the expiration of the TTT timer if the handover to the Wi-Fi cell is completed.

19. The apparatus of claim 17 , wherein the measurement report is not transmitted at the expiration of the TTT time if the first network does not have the active transmission.

20. The apparatus of claim 11 , wherein the at least one processor is further configured to:
determine whether a signal strength of the second target cell is greater than a signal strength of the active transmission on the first network, such that the first network is preparing to initiate the handover to the second target cell.

21. A method of wireless communication at a base station, comprising:
communicating, with a user equipment (UE), on a first network, wherein an active transmission occurs between the base station and the UE;
receiving, from the UE, an indication to perform a handover of the active transmission to a Wi-Fi cell, wherein the Wi-Fi cell is a first target cell from a plurality of target cells, wherein the base station receives the indication to perform the handover of the active transmission to the Wi-Fi cell prior to an expiration of a time-to-trigger (TTT) timer and prior to the first network initiating a handover to a second target cell, from the plurality of target cells, on a second network; and
performing the handover of the active transmission to the Wi-Fi cell in response to the indication received from the UE.

22. The method of claim 21 , further comprising:
transmitting, to the UE, handover thresholds for a handover between the first network and a second network.

23. The method of claim 21 , wherein the Wi-Fi cell is viable as the first target cell serving the UE to continue the active transmission on the Wi-Fi cell based on at least a signal strength of the Wi-Fi cell.

24. The method of claim 21 , wherein the base station receives the indication to perform the handover of the active transmission to the Wi-Fi cell if a signal strength of the Wi-Fi cell is greater than a signal strength of the first network.

25. An apparatus for wireless communication at a base station, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
communicate, with a user equipment (UE), on a first network, wherein an active transmission occurs between the base station and the UE;
receive, from the UE, an indication to perform a handover of the active transmission to a Wi-Fi cell, wherein the Wi-Fi cell is a first target cell from a plurality of target cells, wh

Assignees

• Qualcomm Inc

Inventors

• Xie Yong
• Santhanam Arvind Vardarajan
• Pazos Carlos Marcelo Dias
• Singh Vikram
• Ambriss Mouaffac
• Singh Sumit Kumar

Classifications

• H04B17/318

  Received signal strength · CPC title

• H04W36/0058 Primary

  Transmission of hand-off measurement information, e.g. measurement reports · CPC title

• H04W36/1446

  wherein at least one of the networks is unlicensed · CPC title

• H04W36/00837 Primary

  Determination of triggering parameters for hand-off · CPC title

• H04W36/00692

  using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] (allocation of physical resources in CoMP or in CA H04L5/0035) · CPC title