# US 2025/0168664 A1 · Time alignment timer handling in wireless communications

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- Number: US 2025/0168664 A1
- Document ID: US20250168664A1
- Status: Published application
- Kind: A1
- Application number: 18/834,859
- Filed: 2023-02-01
- Published: 2025-05-22
- Earliest claimed: 2022-02-15
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Hongsuk KIM; Sunghoon JUNG; Sunyoung LEE
- Web page: https://patentgrep.com/patent/US20250168664A1

## CPC

- H04W 24/04: Arrangements for maintaining operational condition
- H04W 76/19: Connection re-establishment
- H04L 69/28: Timers or timing mechanisms used in protocols
- H04W 56/001: {Synchronization between nodes}
- H04W 56/0045: {compensating for timing error by altering transmission time}
- H04W 76/15: Setup of multiple wireless link connections
- H04W 76/18: Management of setup rejection or failure
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The present disclosure relates to a time alignment timer handling in wireless communications. According to an embodiment of the present disclosure, a user equipment (UE) may initiate a transmission of failure information for a cell group based on detecting a failure on the cell group. The UE may consider a time alignment (TA) timer related to a TA configuration for the cell group as expired based on initiating the transmission of the failure information. After transmitting the failure information, the UE may receive a configuration for failure recovery of the failure on the cell group. The UE may restart the TA timer related to the TA configuration for the cell group based on receiving the configuration for failure recovery.

## Claims

### Claim 1

A method performed by a user equipment (UE) in a wireless communication system, the method comprising:
receiving a time alignment (TA) configuration;
starting a TA timer related to the TA configuration for a cell group:
initiating a transmission of failure information for the cell group based on detecting a failure on the cell group, wherein the TA timer for the cell group expires based on the transmission of the failure information being initiated:
transmitting the failure information for the cell group:
receiving a configuration for failure recovery of the failure on the cell group after transmitting the failure information; and
restarting the TA timer related to the TA configuration for the cell group based on receiving the configuration for failure recovery.

### Claim 2 (depends on 1)

The method of claim 1, wherein the restarting of the TA timer comprises restarting the TA timer related to the TA configuration for the cell group upon a reception of the configuration for failure recovery.

### Claim 3 (depends on 1)

The method of claim 1, wherein the TA timer has a time duration, and
wherein the restarting of the TA timer comprises restarting the TA timer related to the TA configuration for the cell group, based on receiving the configuration for failure recovery within the time duration from when the TA timer is started.

### Claim 4 (depends on 3)

The method of claim 3, wherein the restarted TA timer runs for a rest time period of the time duration,
wherein the rest time period is the time duration minus a time period from when the TA timer is started to a time point, and
wherein the time point comprises at least one of:
a time point when the configuration for failure recovery is received: or
a time point when the TA timer is restarted.

### Claim 5 (depends on 1)

The method of claim 1, wherein the TA configuration is received before the configuration for failure recovery is received.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
determining that the failure on the cell group is recovered based on receiving the configuration for failure recovery.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
deactivating the cell group; and
while the cell group is deactivated:
performing a link monitoring on the cell group; and
detecting the failure on the cell group based on the link monitoring,
wherein the initiating of the transmission of the failure information comprises while the SCG is deactivated, initiating the transmission of the failure information for the cell group based on detecting the failure on the cell group.

### Claim 8 (depends on 7)

The method of claim 7, wherein the link monitoring comprises at least one of a radio link monitoring (RLM) or a beam failure detection (BFD), and
wherein the failure comprises at least one of a radio link failure (RLF) related to the RLM or a beam failure (BF) related to the BFD.

### Claim 9 (depends on 7)

The method of claim 7, further comprising:
activating the cell group without performing a random access to the cell group, while the TA timer is running after restarting the TA timer.

### Claim 10 (depends on 9)

The method of claim 9, wherein the activating of the cell group without performing a random access to the cell group comprises performing a random access channel (RACH)-less activation of the cell group based on at least one of conditions being met, and
wherein the conditions comprise:
a condition that a radio link failure (RLF) is not detected or RLF is recovered:
a condition that a beam failure (BF) is not detected or BF is recovered:
a condition that the TA timer does not expire or is running; and
a condition that an indication to perform the RACH-less activation is received from a network.

### Claim 11 (depends on 7)

The method of claim 7, further comprising:
activating the cell group by performing a random access to the cell group, after the TA timer expires.

### Claim 12 (depends on 1)

The method of claim 1, wherein the cell group comprises a secondary cell group (SCG) including a primary secondary cell (PSCell).

### Claim 13 (depends on 1)

The method of claim 1, wherein the UE is in communication with at least one of a mobile device, a network, or autonomous vehicles other than the UE.

### Claim 14

A user equipment (UE) adapted to operate in a wireless communication system, the UE comprising:
at least one transceiver:
at least processor; and
at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
receiving a time alignment (TA) configuration:
starting a TA timer related to the TA configuration for a cell group:
initiating a transmission of failure information for the cell group based on detecting a failure on the cell group, wherein the TA timer for the cell group expires based on the transmission of the failure information being initiated;
transmitting the failure information for the cell group:
receiving a configuration for failure recovery of the failure on the cell group after transmitting the failure information; and
restarting the TA timer related to the TA configuration for the cell group based on receiving the configuration for failure recovery.

### Claim 15

A network node adapted to operate in a wireless communication system, the network node comprising:
at least one transceiver:
at least processor; and
at least one computer memory operably connectable to the at least one processor and storing instructions that, based on being executed by the at least one processor, perform operations comprising:
transmitting, to a user equipment (UE), a time alignment (TA) configuration;
receiving, from the UE, failure information for a cell group on which a failure is detected; and
transmitting, to the UE, a configuration for failure recovery of the failure on the cell group after receiving the failure information,
wherein a TA timer related to the TA configuration for the cell group expires based on a transmission of the failure information being initiated by the UE, and
wherein the TA timer related to the TA configuration for the cell group is restarted based on the configuration for failure recovery being received by the UE.

### Claim at position 16

16-18. (canceled)