CN-121986518-A - Timing Advance (TA) acquisition procedure based on User Equipment (UE) capability in a wireless network

Abstract

A method includes identifying a capability of a UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell based on UE capability information received from the UE. During configuration preparation of the LTM in the UE, UE capability information is transmitted to a service Distributed Unit (DU). UE capability information is sent to candidate/target DUs associated with LTM candidate/target cells selected from the LTM candidate cells. An acknowledgement is received from the serving DU and/or the candidate/target DU indicating that no Physical Random Access Channel (PRACH) resources are allocated to the UE, the PRACH resources being used to perform Uplink (UL) synchronization to acquire the TA of the LTM candidate/target cell.

Inventors

• S. Chandra chekka

Assignees

• 乐天交响乐株式会社

Dates

Publication Date

20260505

Application Date

20240708

Priority Date

20231103

Claims (18)

1. 1. A method, comprising: identifying, by a Centralized Unit (CU), a capability of a UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell based on UE capability information received from the UE; Transmitting, by the CU, the UE capability information to a service Distribution Unit (DU) during configuration preparation of the LTM in the UE; Transmitting, by the CU, the UE capability information to a candidate/target DU associated with an LTM candidate/target cell selected from the LTM candidate cells, and An acknowledgement is received by the CU from the serving DU and/or the candidate/target DU, the acknowledgement indicating that no Physical Random Access Channel (PRACH) resources are allocated to the UE, the PRACH resources being used to perform Uplink (UL) synchronization to acquire the TA of the LTM candidate/target cell.
2. 2. The method of claim 1, wherein the UE capability information is received from the UE in an RRC message during or after a Radio Resource Control (RRC) setup procedure.
3. 3. The method of claim 1, wherein the UE capability information is sent to the candidate/target DU during preparation of the LTM candidate/target cell.
4. 4. The method according to claim 1, comprising: upon receiving the UE capability information, the UE is configured to perform UE capability-based TA measurement of the LTM candidate cell.
5. 5. A method, comprising: receiving, by a serving Distributed Unit (DU), from a Centralized Unit (CU) during configuration preparation of LTM in a User Equipment (UE), UE capability information indicating the UE's ability to perform Timing Advance (TA) measurements of LTM candidate cells, and An acknowledgement is sent by the service DU to the CU, the acknowledgement indicating that a Physical Random Access Channel (PRACH) resource is not allocated, the PRACH resource for performing Uplink (UL) synchronization to acquire a TA of an LTM candidate/target cell selected from the LTM candidate cells.
6. 6. The method of claim 5, further comprising: a cell Identification (ID) of the LTM candidate/target cell is sent to the UE to determine the TA of the LTM candidate/target cell.
7. 7. The method of claim 6 wherein the cell IDs of the LTM candidate/target cells are sent to the UE in a Physical Downlink Control Channel (PDCCH) command to calculate the TAs of the candidate/target cells.
8. 8. The method of claim 6, wherein the cell IDs of the LTM candidate/target cells are sent to the UE in an LTM cell switch command to calculate the TA of the candidate/target cells.
9. 9. The method of claim 6, wherein the UE determines the TA of the LTM candidate/target cell based on a receiver (Rx) timing difference between a current serving cell of the UE and the LTM candidate/target cell, and a TA of the current serving cell.
10. 10. A Centralized Unit (CU) configured to: based on UE capability information received from a UE, identifying a capability of the UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell; Transmitting the UE capability information to a service Distribution Unit (DU) during configuration preparation of the LTM in the UE; Transmitting the UE capability information to a candidate/target DU associated with an LTM candidate/target cell selected from the LTM candidate cells, and An acknowledgement is received from the service DU and/or the candidate/target DU, the acknowledgement indicating that no Physical Random Access Channel (PRACH) resources are allocated to the UE, the PRACH resources being used to perform Uplink (UL) synchronization to acquire the TA of the LTM candidate/target cell.
11. 11. The CU of claim 10, wherein the CU receives the UE capability information from the UE in an RRC message during or after a Radio Resource Control (RRC) setup procedure.
12. 12. The CU of claim 10, wherein the CU sends the UE capability information to the candidate/target DU during preparation of the LTM candidate/target cell.
13. 13. The CU of claim 10, upon receiving the UE capability information, configuring the UE to perform UE capability-based TA measurements of the LTM candidate cell.
14. 14. A service Distributed Unit (DU) configured to: During configuration preparation of LTM in a User Equipment (UE), receiving UE capability information from a Centralized Unit (CU), the UE capability information indicating the UE's ability to perform Timing Advance (TA) measurements of LTM candidate cells, and An acknowledgement is sent to the CU indicating that a Physical Random Access Channel (PRACH) resource is not allocated, the PRACH resource for performing Uplink (UL) synchronization to acquire a TA of an LTM candidate/target cell selected from the LTM candidate cells.
15. 15. The service DU of claim 14, further configured to: a cell Identification (ID) of the LTM candidate/target cell is sent to the UE to determine the TA of the LTM candidate/target cell.
16. 16. The service DU of claim 15, wherein the service DU is configured to send the cell ID of the LTM candidate/target cell to the UE in a Physical Downlink Control Channel (PDCCH) command to calculate the TA of the candidate/target cell.
17. 17. The service DU of claim 15, wherein the service DU is configured to send the cell ID of the LTM candidate/target cell to the UE in an LTM cell handover command to calculate the TA of the candidate/target cell.
18. 18. A non-transitory computer-readable medium comprising instructions for performing operations comprising: based on UE capability information received from a UE, identifying a capability of the UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell; Transmitting the UE capability information to a service Distribution Unit (DU) during configuration preparation of the LTM in the UE; Transmitting the UE capability information to a candidate/target DU associated with an LTM candidate/target cell selected from the LTM candidate cells, and An acknowledgement is received from the service DU and/or the candidate/target DU, the acknowledgement indicating that no Physical Random Access Channel (PRACH) resources are allocated to the UE, the PRACH resources being used to perform Uplink (UL) synchronization to acquire the TA of the LTM candidate/target cell.

Description

Timing Advance (TA) acquisition procedure based on User Equipment (UE) capability in a wireless network Citation of related application The present application claims priority from indian patent application IN 2023-41075290 filed on 3.11.2023, the entire contents of which are incorporated herein by reference. Technical Field The present disclosure relates to a Timing Advance (TA) acquisition procedure based on User Equipment (UE) capabilities in a wireless network. Background Mobility management includes the allocation, control and management of devices, services and infrastructure related to mobile communications. Mobility management is one of the core features in third generation partnership project (3 GPP) mobile communication network technology to provide service continuity for mobile User Equipment (UE). When a UE moves from the coverage area of one cell to another, a handover procedure is initiated to change the serving cell for the UE. low-Level Triggered Mobility (LTM) or L1/L2 based mobility is introduced in Release 18 of the third generation partnership project (3 GPP). The LTM enables serving cell change via L1/L2 signaling while maintaining configuration of upper layers and/or minimizing change of lower layer configuration. LTM provides improvements in handover delay and interruption time compared to layer 3 based mobility. Timing Advance (TA) is used to control uplink transmission timing of each UE. The TA helps to ensure that uplink transmissions from all UEs are synchronized. When switching from an LTM serving cell to an LTM candidate/target cell, the UE needs to perform TA acquisition to acquire the TA of the LTM candidate/target cell. In 3GPP, a decomposition architecture of a gndeb (gNB) is defined to decompose the gNB into a plurality of logical entities. The gNB is split into three logical nodes, namely a Centralized Unit (CU), a Distributed Unit (DU) and a Radio Unit (RU). A single DU may carry multiple cells. For example, a 3GPP definition DU may carry up to 512 cells. The CU (also referred to as a gNB-CU) carries upper layers such as Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC) layers, while the DU (also referred to as a gNB-DU) carries lower layers such as Radio Link Control (RLC), medium Access Control (MAC) and Physical (PHY) layers. The scheduling operation is performed at the gNB-DU. The information disclosed in this background section is only for enhancement of understanding of the general background of the disclosure and is not to be taken as an admission or any form of suggestion that this information forms the prior art that is known to a person skilled in the art. Disclosure of Invention In one embodiment, the present disclosure discloses a method. The method includes identifying a capability of the UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell based on UE capability information received from the UE. Further, the method includes transmitting UE capability information to a service Distribution Unit (DU) during configuration preparation of an LTM in the UE. Further, the method includes transmitting UE capability information to a candidate/target DU associated with an LTM candidate/target cell selected from the LTM candidate cells. Thereafter, the method includes receiving an acknowledgement from the serving DU and/or the candidate/target DU indicating that no Physical Random Access Channel (PRACH) resources are allocated to the UE, the PRACH resources being used to perform Uplink (UL) synchronization to acquire a TA of the LTM candidate/target cell. In one embodiment, the present disclosure discloses a method. The method includes receiving User Equipment (UE) capability information from a Centralized Unit (CU), the UE capability information indicating a capability of the UE to perform Timing Advance (TA) measurements of LTM candidate cells. During configuration preparation of the LTM in the UE, UE capability information is received. Further, the method includes transmitting an acknowledgement to the CU indicating that a Physical Random Access Channel (PRACH) resource is not allocated, the PRACH resource being used to perform Uplink (UL) synchronization to acquire a TA of an LTM candidate/target cell selected from among the LTM candidate cells. In one embodiment, the present disclosure discloses a Centralized Unit (CU). The CU is configured to identify a capability of the UE to perform a Timing Advance (TA) measurement of a layer 1/layer 2 triggered mobility (LTM) candidate cell based on UE capability information received from the UE. Further, the CU is configured to send the UE capability information to a serving Distributed Unit (DU) during configuration preparation of the LTM candidate cell in the UE. Further, the CU is configured to send UE capability information to candidate/target DUs associated with LTM candidate/target cells selected from the LTM candidate cells. Thereafter, the C