Fast retransmission during handover

Patent metadata

Field	Value
Publication number	US-12520207-B2
Application number	US-202118254352-A
Country	US
Kind code	B2
Filing date	Jan 29, 2021
Priority date	Jan 29, 2021
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

Methods, systems, and devices for wireless communications are disclosed by the present application. A request to establish a call using a first connection may be received, the first connection using a first radio access technology to communicate with a radio access network. During execution of a procedure to establish the call, a command to handover communications from the first connection to a second connection that uses a second radio access technology to communicate with the radio access network may be received. The second connection may be established in response to the command, and a message indicating that the request to establish the call was successfully received may be transmitted over the second connection. Also, a message indicating that an alert of the call is being issued may be transmitted over the second connection.

First claim

What is claimed is:

1 . A method for wireless communication at a user equipment (UE), comprising:
receiving, over a first connection with a radio access network, a request to establish a call using the first connection, the first connection using a first radio access technology; receiving, over the first connection as part of a procedure to establish the call, a command to handover communications from the first connection to a second connection with the radio access network, the second connection using a second radio access technology; establishing the second connection with the radio access network at least in part in response to receiving the command; transmitting, using the second connection after establishing the second connection, a first message indicating that the request was successfully received by the UE; and transmitting, using the second connection after transmitting the first message, a second message indicating that an alert of the call is being issued at the UE.

2 . The method of claim 1 , further comprising:
transmitting the first message using the first connection prior to transmitting the first message using the second connection, wherein the first message is transmitted using the second connection based at least in part on the first message being unacknowledged by the radio access network.

3 . The method of claim 2 , further comprising:
starting a timer associated with discarding the first message based at least in part on transmitting the first message using the first connection; and disabling the timer based at least in part on receiving the command.

4 . The method of claim 1 , further comprising:
buffering the first message based at least in part on receiving the command.

5 . The method of claim 1 , further comprising:
buffering a plurality of messages associated with communicating with the radio access network via the first connection based at least in part on receiving the command, the plurality of messages comprising the first message.

6 . The method of claim 5 , further comprising:
identifying a third message associated with communicating with the radio access network via the first connection as having a priority that exceeds a threshold; and determining that the third message was discarded before an acknowledgement was received from the radio access network for the third message, wherein buffering the plurality of messages comprises buffering the third message based at least in part on determining that the third message was discarded.

7 . The method of claim 6 , further comprising:
transmitting the third message using the second connection based at least in part on buffering the third message.

8 . The method of claim 1 , further comprising:
identifying, after establishing the second connection, a third message associated with communicating with the radio access network via the second connection as having a priority that exceeds a threshold; determining that the third message was discarded before an acknowledgement was received from the radio access network for the third message; buffering the third message based at least in part on the third message being discarded; and retransmitting the third message before transmitting other messages in a radio link control buffer.

9 . The method of claim 1 , wherein establishing the second connection comprises:
establishing a radio bearer for the second radio access technology.

10 . The method of claim 1 , wherein the request is an INVITE message, the command is a mobilityfromNRCommand, the first message is a 200 OK message, and the second message is a 180 Ringing message.

11 . An apparatus for wireless communication at a user equipment (UE), comprising:
a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to:
receive, over a first connection with a radio access network, a request to establish a call using the first connection, the first connection using a first radio access technology;
receive, over the first connection as part of a procedure to establish the call, a command to handover communications from the first connection to a second connection with the radio access network, the second connection using a second radio access technology;
establish the second connection with the radio access network at least in part in response to receiving the command;
transmit, using the second connection after establishing the second connection, a first message indicating that the request was successfully received by the UE; and
transmit, using the second connection after transmitting the first message, a second message indicating that an alert of the call is being issued at the UE.

12 . The apparatus of claim 11 , wherein the instructions are further executable by the processor to cause the apparatus to:
transmit the first message using the first connection prior to transmitting the first message using the second connection, wherein the first message is transmitted using the second connection based at least in part on the first message being unacknowledged by the radio access network.

13 . The apparatus of claim 12 , wherein the instructions are further executable by the processor to cause the apparatus to:
start a timer associated with discarding the first message based at least in part on transmitting the first message using the first connection; and disable the timer based at least in part on receiving the command.

14 . The apparatus of claim 11 , wherein the instructions are further executable by the processor to cause the apparatus to:
buffer the first message based at least in part on receiving the command.

15 . The apparatus of claim 11 , wherein the instructions are further executable by the processor to cause the apparatus to:
buffer a plurality of messages associated with communicating with the radio access network via the first connection based at least in part on receiving the command, the plurality of messages comprising the first message.

16 . The apparatus of claim 15 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify a third message associated with communicating with the radio access network via the first connection as having a priority that exceeds a threshold; and determine that the third message was discarded before an acknowledgement was received from the radio access network for the third message, wherein buffering the plurality of messages comprises buffering the third message based at least in part on determining that the third message was discarded.

17 . The apparatus of claim 16 , wherein the instructions are further executable by the processor to cause the apparatus to:
transmit the third message using the second connection based at least in part on buffering the third message.

18 . The apparatus of claim 11 , wherein the instructions to establish the second connection are executable by the processor to cause the apparatus to:
establish a radio bearer for the second radio access technology.

19 . The apparatus of claim 11 , wherein the request is an INVITE message, the command is a mobilityfromNRCommand, the first message is a 200 OK message, and the second message is a 180 Ringing message.

20 . An apparatus for wireless communication at a user equipment (UE), comprising:
means for receiving, over a first connection with a radio access network, a request to establish a call using the first connection, t

Assignees

• Qualcomm Inc

Inventors

• Zhang Nan
• Wu Peng
• Li Yuyi
• Hou Yong
• Guan Mengling
• Zhang Yan
• Qiu Yujie
• Ma Jun
• Teng Yueming
• Maheshwari Shailesh
• Xiao Gang Andy
• Dalmiya Vishal
• Chen Xiaochen
• Rao Vaishakh

Classifications

• H04W36/02

  Buffering or recovering information during reselection {; Modification of the traffic flow during hand-off} · CPC title

• H04W36/249

  according to timing information · CPC title

• H04W76/10

  Connection setup · CPC title

• H04W36/00222

  between different packet switched [PS] network technologies, e.g. transferring data sessions between LTE and WLAN or LTE and 5G · CPC title

• H04W36/0066 Primary

  of control information between different types of networks in order to establish a new radio link in the target network · CPC title