CN-122002442-A - Conditional low-level trigger mobility

CN122002442ACN 122002442 ACN122002442 ACN 122002442ACN-122002442-A

Abstract

The present application relates to conditional low-level trigger mobility. An embodiment of the application discloses a method comprising receiving a message from a source cell, the message comprising a configuration for a condition for conditional low-layer triggering mobility (C-LTM) to a plurality of target cells, and a C-LTM candidate cell configuration for each target cell. Based on the condition, the method includes initiating, by a Medium Access Control (MAC) entity or a Radio Resource Control (RRC) entity, an evaluation of whether the condition of any target cell is met. The method includes determining, by the MAC entity or the RRC entity, that a condition of a subset of target cells among a plurality of target cells is met. The method includes determining, by the MAC entity or the RRC entity, to select a desired target cell for the C-LTM based on a priority of the desired target cell in the subset of target cells exceeding a priority of remaining target cells in the subset of target cells.

Inventors

H.M. Gulsu
A. Kakawas
D. Parka
S. GOYAL
J. Steinchuck
S Saierwajianapasi

Assignees

诺基亚技术有限公司

Dates

Publication Date: 20260508
Application Date: 20251108
Priority Date: 20241108

Claims (10)

1. A method performed by a terminal device, comprising: Receiving a message from a source cell, the message comprising: Configuration of conditions for conditional low-level triggered mobility (C-LTM) to multiple target cells; C-LTM candidate cell configuration for each of the plurality of target cells; initiating, by a Medium Access Control (MAC) entity or a Radio Resource Control (RRC) entity of the terminal device, an evaluation of whether the condition of any of the plurality of target cells is met based on the condition; Determining, by the MAC entity or the RRC entity, that the condition of a subset of target cells among the plurality of target cells is satisfied, and Determining, by the MAC entity or the RRC entity, to select a desired target cell for the C-LTM based on the priority of the desired target cell in the subset of target cells exceeding the priority of the remaining target cells in the subset of target cells.
2. The method of claim 1, wherein the conditions for the C-LTM comprise: layer 1 (L1) condition, or Layer 3 (L3) condition.
3. The method of claim 2, wherein the priority of the desired target cell over the priority of the remaining target cells is based on an indication of at least one of: the C-LTM to the desired target cell is performed without a Random Access Channel (RACH), and the C-LTM to the remaining target cells is RACH based; The condition of the C-LTM to the desired target cell has a higher priority than the condition for the C-LTM to the remaining target cells; the C-LTM to the desired target cell has a higher priority than Conditional Handover (CHO) l; The C-LTM candidate cell configuration of the desired target cell; A specific frequency of the desired target cell; An activated Transmission Configuration Indicator (TCI) state of the desired target cell; The C-LTM to the desired target cell is a cell change within a Distributed Unit (DU); the C-LTM to the desired target cell is a cell change within a Central Unit (CU), or The desired target cell has a greater number of component carriers than each of the remaining target cells.
4. The method of claim 1, wherein the determination of the network node associated with the source cell to decide to select the desired target cell is performed by the MAC entity or the RRC entity.
5. A method performed by a terminal device, comprising: Receiving a message from a source cell, the message comprising: Configuration of a first type of condition for a conditional lower layer trigger mobility (C-LTM) to an initial target cell group; C-LTM candidate cell configuration for each target cell in the initial target cell group; initiating, by a Medium Access Control (MAC) entity or a Radio Resource Control (RRC) entity of the terminal device, an evaluation of whether the condition of any target cell of the initial set of target cells is fulfilled, based on the first type of condition; Determining, by the MAC entity or the RRC entity, that the first type of condition of a target cell subset among the initial target cell sets is met; Receiving, by the RRC entity, information indicating: a condition for Conditional Handover (CHO) to the second target cell group is satisfied, and A second type of condition for the C-LTM to a third target cell group is satisfied; determining, by the MAC entity or the RRC entity, to select a desired target cell based on a priority of the desired target cell, and wherein the desired target cell is one of: The target cell subset; The second target cell group; the third target cell group.
6. The method according to claim 5, wherein: The first type of conditions for the C-LTM include layer 1 (L1) conditions, and The second type of conditions for the C-LTM include layer 3 (L3) conditions, Or vice versa.
7. The method of claim 5, wherein the priority of the desired target cell is based on an indication of at least one of: said C-LTM has a higher priority than said CHO; The C-LTM associated with the first type of condition has a higher priority than the C-LTM associated with the second type of condition, or vice versa; the C-LTM to the desired target cell is Random Access Channel (RACH) free; Candidate cell configuration of the desired target cell; A specific frequency of the desired target cell; An activated Transmission Configuration Indicator (TCI) state of the desired target cell; The C-LTM to the desired target cell is a cell change within a Distributed Unit (DU); The C-LTM to the desired target cell is a cell change within a Central Unit (CU), and The desired target cell has the highest number of component carriers among: The target cell subset; The second target cell group; the third target cell group.
8. The method of claim 5, further comprising: Determining by the MAC entity: A Timing Advance (TA) value for use with the C-LTM, or And transmitting RACH to the expected target cell.
9. A terminal device, comprising: at least one memory storing a plurality of instructions, and At least one processor configured to execute the plurality of instructions to cause the terminal device to perform the method according to any one of claims 1 to 4.
10. A terminal device, comprising: at least one memory storing a plurality of instructions, and At least one processor configured to execute the plurality of instructions to cause the terminal device to perform the method according to any one of claims 5 to 8.

Description

Conditional low-level trigger mobility Technical Field The present disclosure relates to the field of wireless communications. Background Certain abbreviations that may be found in the specification and/or drawings are defined herein as follows. A User Equipment (UE) may be handed over from a serving cell to a target cell using one or more mobility procedures. One conventional mobility procedure is Handover (HO), in which the UE is handed over to the target cell via RRC signaling. Conditional Handover (CHO) is a type of mobility procedure in which the UE evaluates whether the conditions for CHO to the target cell are met. When the evaluation condition is satisfied, the UE performs CHO using a condition configuration provided by the network. Layer 1/layer 2 (L1/L2) Triggered Mobility (LTM), introduced by the third generation partnership project (3 GPP) release 18 (Rel-18), is a cell handover procedure in which the serving cell of a UE is handed over by the network via an LTM cell handover command. The LTM cell switch command may be delivered through Medium Access Control (MAC) signaling (i.e., L2 signaling) using MAC CE (control element). The conditional LTM (C-LTM) is a type of mobility procedure in which the UE evaluates the conditions for the C-LTM to proceed to the target cell. The condition may be L1-based or L3-based. Disclosure of Invention Aspects related to example embodiments of the present disclosure are set forth below. It should be understood that these aspects are not intended to limit the scope of the present disclosure. Indeed, the disclosure may encompass a variety of aspects that may not be set forth below. In a first aspect of the present disclosure, a method performed by a terminal device is provided. The method includes receiving a message from a source cell, the message including a configuration of a condition for triggering mobility (C-LTM) to a conditional layer 1/layer 2 of a plurality of target cells, and a configuration of a C-LTM candidate cell for each of the plurality of target cells. The method comprises initiating, by a Medium Access Control (MAC) entity or a Radio Resource Control (RRC) entity of the terminal device, an evaluation of whether a condition of any of the plurality of target cells is fulfilled, based on the condition. The method includes determining, by the MAC entity or the RRC entity, that a condition of a subset of target cells among a plurality of target cells is met. The method includes determining, by the MAC entity or the RRC entity, to select a desired target cell for the C-LTM based on a priority of the desired target cell in the subset of target cells exceeding a priority of remaining target cells in the subset of target cells. In a second aspect of the present disclosure, a method performed by a terminal device is provided. The method includes receiving a message from a source cell, the message including a configuration of a first type of condition for conditional low-level triggered mobility (C-LTM) to an initial set of target cells, and a C-LTM candidate cell configuration for each target cell in the initial set of target cells. The method comprises initiating, by a Medium Access Control (MAC) entity or a Radio Resource Control (RRC) entity of the terminal device, an evaluation of whether a condition of any target cell of the initial set of target cells is fulfilled, based on a first type of condition. The method includes determining, by the MAC entity or the RRC entity, that a condition of a subset of target cells among a plurality of target cells is met. The method includes receiving, by the RRC entity, information indicating that a condition for Conditional Handover (CHO) to a second target cell group is satisfied and that a condition for a second type of C-LTM to a third target cell group is satisfied. The method includes determining, by the MAC entity or the RRC entity, to select a desired target cell based on a priority of the desired target cell, and wherein the desired target cell is one of a subset of target cells, a second set of target cells, or a third set of target cells. In a third aspect of the present disclosure, a terminal device is provided. The terminal device comprises at least one memory storing a plurality of instructions and at least one processor configured to execute the plurality of instructions to cause the terminal device to perform the method as in the first aspect. In a fourth aspect of the present disclosure, a terminal device is provided. The terminal device comprises at least one memory storing a plurality of instructions and at least one processor configured to execute the plurality of instructions to cause the terminal device to perform the method as in the second aspect. The details of example embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims. Drawings The