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EP-4740580-A1 - TCI BEFORE AND AFTER CELL SWITCH COMMAND IN CANDIDATE CELL AND ACTIVATED TCI SELECTION FOR LTM

EP4740580A1EP 4740580 A1EP4740580 A1EP 4740580A1EP-4740580-A1

Abstract

Apparatuses and methods for TCI before and after a cell switch command in a candidate cell and activated TCI selection for LTM are descried. An apparatus is configured to receive a second TCI state list associated with target cell UE mobility. The apparatus is configured to activate, after a serving cell to target cell switch, based on a state list indication, a first TCI state list associated with a target cell configuration at the UE and/or the second TCI state list. Another apparatus is configured to activate, before a serving cell to target cell switch, a first TCI state list associated with a serving cell configuration of the UE and/or a second TCI state list associated with a target cell configuration for UE mobility. The apparatus is configured to maintain, after the switch, based on a state list indication, at least the second TCI state list activated at the UE.

Inventors

  • YUAN, FANG
  • ZHOU, YAN

Assignees

  • QUALCOMM Incorporated

Dates

Publication Date
20260513
Application Date
20230706

Claims (20)

  1. An apparatus for wireless communication at a user equipment (UE) , comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor, individually or in any combination, is configured to: receive, from a network node, a second transmission configuration indication (TCI) state list associated with mobility of the UE for a target cell; and activate, subsequent to a switch from a serving cell to the target cell and based on a state list indication, at least one of a first TCI state list associated with a cell configuration of the target cell at the UE or the second TCI state list.
  2. The apparatus of claim 1, wherein the state list indication is a set of state list conditions, wherein to activate at least one of the first TCI state list or the second TCI state list, the at least one processor, individually or in any combination, is configured to: activate the first TCI state list and the second TCI state list simultaneously based on the set of state list conditions.
  3. The apparatus of claim 2, wherein the first TCI state list and the second TCI state list comprise a same TCI identifier (ID) pool and have different TCI ID subsets of the TCI ID pool; or wherein the first TCI state list is a subset of the second TCI state list.
  4. The apparatus of claim 1, wherein the state list indication is a set of state list conditions, wherein to activate at least one of the first TCI state list or the second TCI state list, the at least one processor, individually or in any combination, is configured to: activate the second TCI state list by replacing the first TCI state list.
  5. The apparatus of claim 4, wherein the mobility of the UE for the target cell is Layer 1/Layer 2 (L1/L2) triggered mobility (LTM) , wherein the UE replaces the first TCI state list based on its association with the LTM.
  6. The apparatus of claim 1, wherein the second TCI state list is present at the UE prior to receiving the first TCI state list.
  7. The apparatus of claim 1, wherein the UE supports a maximum number of concurrently active TCIs, wherein the maximum number of concurrently active TCIs corresponds to at least two concurrently active TCIs, and wherein receiving the second TCI state list comprises receiving the first TCI state list at a different time occasion than the second TCI state list; wherein the at least one processor, individually or in any combination, is further configured to: maintain, subsequent to the switch from the serving cell to the target cell and based on the state list indication, the first TCI state list and the second TCI state list.
  8. The apparatus of claim 7, wherein the state list indication is a set of state list conditions, maintained at the UE, which indicates maintenance of at most the maximum number of concurrently active TCIs that are most recently activated TCIs, wherein the first TCI state list and the second TCI state list are included in the most recently activated TCIs; or wherein to maintain the first TCI state list and the second TCI state list, the at least one processor, individually or in any combination, is configured to: receive, from the network node, the state list indication, and maintain the first TCI state list and the second TCI state list based on the received state list indication.
  9. The apparatus of claim 8, wherein to maintain the first TCI state list and the second TCI state list, the at least one processor, individually or in any combination, is configured to replace at least a third TCI state list that is active at the UE with at least one of the first TCI state list or the second TCI state list based on the third TCI state list having an activation time that is older than activation times of the most recently activated TCIs.
  10. The apparatus of claim 1, wherein the UE supports a maximum number of concurrently active TCIs for a set of candidate cells, wherein the UE is configured to maintain a target number of concurrently active TCIs for the target cell, wherein the target cell is included in the set of candidate cells, and wherein to receive the second TCI state list, the at least one processor, individually or in any combination, is configured to receive a third TCI state list associated with a candidate cell configuration that is separate from the cell configuration of the target cell; wherein the at least one processor, individually or in any combination, is further configured to: maintain or deactivate, subsequent to the switch from the serving cell to the target cell and based on the state list indication, the third TCI state list.
  11. The apparatus of claim 10, wherein the state list indication is a set of state list conditions that indicates a set of lowest TCI identifiers (IDs) , and wherein to maintain or deactivate the third TCI state list, the at least one processor, individually or in any combination, is configured to: maintain or deactivate the third TCI state list based on TCIs associated with the third TCI state list having TCI IDs in the set of lowest TCI IDs.
  12. The apparatus of claim 10, wherein the state list indication indicates a separate TCI activation for the third TCI state list, wherein to maintain or deactivate the third TCI state list, the at least one processor, individually or in any combination, is configured to: receive, from the network node, the state list indication; and maintain or deactivate the third TCI state list based on the received state list activation.
  13. The apparatus of claim 10, wherein the state list indication is a set of state list conditions that indicates maintenance of the target number of concurrently active TCIs for the target cell and deactivation for a remaining portion of active TCIs associated with the set of candidate cells, and wherein to maintain or deactivate the third TCI state list, the at least one processor, individually or in any combination, is configured to: maintain or deactivate the third TCI state list based on the set of state list conditions.
  14. The apparatus of claim 10, wherein the state list indication indicates a subset of the candidate cells, wherein to maintain or deactivate the third TCI state list, the at least one processor, individually or in any combination, is configured to: receive, from the network node, the state list indication; and maintain or deactivate the third TCI state list based on the third TCI state list being associated with a candidate cell included in the subset of the candidate cells that is indicated by the received state list activation.
  15. The apparatus of claim 1, wherein the at least one processor, individually or in any combination, is further configured to: transmit, for the network node, a capability indication that indicates at least one capability of the UE associated with the mobility of the UE, wherein the at least one capability indicates support for at least one of: a first maximum number of concurrently active TCIs, a second maximum number of concurrently active TCIs for a set of candidate cells, a single active TCI, a maintenance of a TCI after a cell switch, a first TCI activation prior to a switching command, or a second TCI activation concurrent with the switching command.
  16. An apparatus for wireless communication at a user equipment (UE) , comprising: at least one memory; and at least one processor coupled to the at least one memory and, based at least in part on information stored in the at least one memory, the at least one processor, individually or in any combination, is configured to: activate, prior to a switch from a serving cell to a target cell, at least one of a first transmission configuration indication (TCI) state list associated with a first cell configuration of the serving cell of the UE or a second TCI state list associated with a second cell configuration of the target cell for mobility of the UE; and maintain, subsequent to the switch from the serving cell to the target cell and based on a state list indication, at least the second TCI state list as activated at the UE.
  17. The apparatus of claim 16, wherein the state list indication is a set of state list conditions, wherein to maintain at least the second TCI state list as activated at the UE, the at least one processor, individually or in any combination, is configured to: maintain the first TCI state list as activated at the UE based on the set of state list conditions; or deactivate the first TCI state list at the UE based on the set of state list conditions.
  18. The apparatus of claim 17, wherein the mobility of the UE for the target cell is Layer 1/Layer 2 (L1/L2) triggered mobility (LTM) , wherein the UE replaces the first TCI state list based on its association with the LTM.
  19. The apparatus of claim 17, wherein the UE supports a maximum number of concurrently active TCIs, wherein the maximum number of concurrently active TCIs corresponds to at least two concurrently active TCIs, and: wherein to maintain the first TCI state list as activated at the UE based on the set of state list conditions, the at least one processor, individually or in any combination, is configured to maintain the first TCI state list as activated at the UE for a duration of time subsequent to the switch from the serving cell to the target cell and based on the set of state list conditions; or wherein to deactivate the first TCI state list at the UE based on the set of state list conditions, the at least one processor, individually or in any combination, is configured to deactivate the first TCI state list at the UE based on the set of state list conditions indicating a deactivation of the first TCI state list at the UE when a total number of concurrently active TCIs at the UE is greater than the maximum number of concurrently active TCIs supported by the UE.
  20. The apparatus of claim 19, wherein the at least one processor, individually or in any combination, is further configured to: switch from the serving cell to the target cell; and switch back to the serving cell, utilizing the first TCI state list that is maintained as activated at the UE for the duration of time, based on a failure associated with the switch from the serving cell to the target cell.

Description

TCI BEFORE AND AFTER CELL SWITCH COMMAND IN CANDIDATE CELL AND ACTIVATED TCI SELECTION FOR LTM TECHNICAL FIELD The present disclosure relates generally to communication systems, and more particularly, to wireless communications systems and user equipment (UE) mobility. INTRODUCTION Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems. These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra-reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. BRIEF SUMMARY The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus is configured to receive, from a network node, a second transmission configuration indication (TCI) state list associated with mobility of the UE for a target cell. The apparatus is also configured to activate, subsequent to a switch from a serving cell to the target cell and based on a state list indication, at least one of a first TCI state list associated with a cell configuration of the target cell at the UE or the second TCI state list. In the aspects, the method includes receiving, from a network node, a second TCI state list associated with mobility of the UE for a target cell. The method also includes activating, subsequent to a switch from a serving cell to the target cell and based on a state list indication, at least one of a first TCI state list associated with a cell configuration of the target cell at the UE or the second TCI state list. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus is configured to activate, prior to a switch from a serving cell to a target cell, at least one of a first TCI state list associated with a first cell configuration of the serving cell of the UE or a second TCI state list associated with a second cell configuration of the target cell for mobility of the UE. The apparatus is also configured to maintain, subsequent to the switch from the serving cell to the target cell and based on a state list indication, at least the second TCI state list as activated at the UE. In the aspects, the method includes activating, prior to a switch from a serving cell to a target cell, at least one of a first TCI state list associated with a first cell configuration of the serving cell of the UE or a second TCI state list associated with a second cell configuration of the target cell for mobility of the UE. The method also includes maintaining, subsequent to the switch from the serving cell to the target cell and based on a state list indication, at least the second TCI state list as activated at the UE. To the accomplishment of the foregoing and related ends, the one or more aspects may include the features hereinafter fully described and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of the one or more aspects. These features