US-20260129613-A1 - METHOD AND APPARATUS FOR PERFORMING LOWER-LAYER TRIGGERED MOBILITY OF USER EQUIPMENT USING CONDITIONS IN A WIRELESS COMMUNICATION SYSTEM

Abstract

The disclosure relates to a 5 th generation (5G) or 6 th generation (6G) communication system for supporting a higher data transmission rate. A method and an apparatus are provided. According to an embodiment, the method performed by a user equipment (UE) in a wireless communication system comprises receiving, from a base station (BS), configuration information for a layer ½ triggered mobility (LTM), and condition information for a conditional LTM (CLTM), identifying a candidate cell for the CLTM based on the condition information, identifying a candidate beam of the identified candidate cell based on the condition information, performing a condition evaluation for the candidate beam of the candidate cell based on a layer 1 (L1) measurement for the candidate beam, and performing a CLTM procedure for the candidate cell based on an corresponding LTM candidate configuration included in the configuration information, in case that a condition in the condition information is fulfilled for the candidate beam.

Inventors

• June Hwang
• Seungri Jin

Assignees

• SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date

20260507

Application Date

20251107

Priority Date

20241107

Claims (20)

1. 1 . A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a base station (BS), configuration information for a layer ½ triggered mobility (LTM), and condition information for a conditional LTM (CLTM); identifying a candidate cell for the CLTM based on the condition information; identifying a candidate beam of the identified candidate cell based on the condition information; performing a condition evaluation for the candidate beam of the candidate cell based on a layer 1 (L1) measurement for the candidate beam; and performing a CLTM procedure for the candidate cell based on an corresponding LTM candidate configuration included in the configuration information, in case that a condition in the condition information is fulfilled for the candidate beam.
2. 2 . The method of claim 1 , wherein the condition information includes an indicator for indicating a candidate identifier (ID) of the candidate cell for the CLTM, wherein the candidate ID is associated with an LTM-channel state information (CSI) report configuration identifier (ID) for indicating the condition.
3. 3 . The method of claim 2 , wherein the condition evaluation is performed based on an event associated with the LTM-CSI report configuration ID, wherein an LTM-CSI report configuration corresponding to the LTM-CSI report configuration ID includes an indicator for indicating a type of the event.
4. 4 . The method of claim 3 , wherein the type of the event is an LTM3 event or an LTM5 event.
5. 5 . The method of claim 3 , wherein the LTM-CSI report configuration further includes a time-to-trigger (TTT) parameter for the event, wherein the condition is fulfilled in case that the event is fulfilled during the TTT.
6. 6 . The method of claim 3 , wherein the LTM-CSI report configuration further includes a hysteresis parameter for the event.
7. 7 . The method of claim 3 , wherein the condition information is associated with an LTM-CSI resource configuration ID associated with the LTM-CSI report configuration, wherein the candidate beam is identified based on the LTM-CSI resource configuration ID.
8. 8 . The method of claim 7 , wherein an LTM-CSI resource configuration corresponding to the LTM-CSI resource configuration ID includes a channel state information-reference signal (CSI-RS) resource ID or a synchronization signal block (SSB) index for indicating a resource for the L1 measurement.
9. 9 . A method performed by a base station (BS) in a wireless communication system, the method comprising: transmitting, to a user equipment (UE), configuration information for a layer ½ triggered mobility (LTM), and condition information for a conditional LTM (CLTM); and performing a CLTM procedure for a candidate cell based on an corresponding LTM candidate configuration included in the configuration information, in case that a condition in the condition information is fulfilled for a candidate beam of the candidate cell, wherein an identification of the candidate cell and the candidate beam is based on the condition information, wherein an evaluation of the condition is based on a layer 1 (L1) measurement for the candidate beam.
10. 10 . The method of claim 9 , wherein the condition information includes an indicator for indicating a candidate identifier (ID) of the candidate cell for the CLTM, wherein the candidate ID is associated with an LTM-channel state information (CSI) report configuration identifier (ID) for indicating the condition.
11. 11 . A user equipment (UE) comprising: at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and at least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the UE to: receive, from a base station (BS), configuration information for a layer ½ triggered mobility (LTM), and condition information for a conditional LTM (CLTM), identify a candidate cell for the CLTM based on the condition information, identify a candidate beam of the identified candidate cell based on the condition information, perform a condition evaluation for the candidate beam of the candidate cell based on a layer 1 (L1) measurement for the candidate beam, and perform a CLTM procedure for the candidate cell based on an corresponding LTM candidate configuration included in the configuration information, in case that a condition in the condition information is fulfilled for the candidate beam.
12. 12 . The UE of claim 11 , wherein the condition information includes an indicator for indicating a candidate identifier (ID) of the candidate cell for the CLTM, wherein the candidate ID is associated with an LTM-channel state information (CSI) report configuration identifier (ID) for indicating the condition.
13. 13 . The UE of claim 12 , wherein the condition evaluation is performed based on an event associated with the LTM-CSI report configuration ID, wherein an LTM-CSI report configuration corresponding to the LTM-CSI report configuration ID includes an indicator for indicating a type of the event.
14. 14 . The UE of claim 13 , wherein the type of the event is an LTM3 event or an LTM5 event.
15. 15 . The UE of claim 13 , wherein the LTM-CSI report configuration further includes a time-to-trigger (TTT) parameter for the event, wherein the condition is fulfilled in case that the event is fulfilled during the TTT.
16. 16 . The UE of claim 13 , wherein the LTM-CSI report configuration further includes a hysteresis parameter for the event.
17. 17 . The UE of claim 13 , wherein the condition information is associated with an LTM-CSI resource configuration ID associated with the LTM-CSI report configuration, wherein the candidate beam is identified based on the LTM-CSI resource configuration ID.
18. 18 . The UE of claim 17 , wherein an LTM-CSI resource configuration corresponding to the LTM-CSI resource configuration ID includes a channel state information-reference signal (CSI-RS) resource ID or a synchronization signal block (SSB) index for indicating a resource for the L1 measurement.
19. 19 . A base station (BS) comprising: at least one transceiver; at least one processor communicatively coupled to the at least one transceiver; and at least one memory, communicatively coupled to the at least one processor, storing instructions executable by the at least one processor individually or in any combination to cause the BS to: transmit, to a user equipment (UE), configuration information for a layer ½ triggered mobility (LTM), and condition information for a conditional LTM (CLTM), and perform a CLTM procedure for a candidate cell based on an corresponding LTM candidate configuration included in the configuration information, in case that a condition in the condition information is fulfilled for a candidate beam of the candidate cell, wherein an identification of the candidate cell and the candidate beam is based on the condition information, wherein an evaluation of the condition is based on a layer 1 (L1) measurement for the candidate beam.
20. 20 . The BS of claim 19 , wherein the condition information includes an indicator for indicating a candidate identifier (ID) of the candidate cell for the CLTM, wherein the candidate ID is associated with an LTM-channel state information (CSI) report configuration identifier (ID) for indicating the condition.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is based on and claims priority under 35 U.S.C. § 119(a) of a Korean patent application number 10-2024-0157305, filed on Nov. 7, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. BACKGROUND 1. Field The disclosure relates to a wireless communication system. More particularly, the disclosure relates to a method and an apparatus for performing lower-layer mobility of a terminal by using a condition in a wireless communication system. 2. Description of Related Art 5th generation (5G) mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in “Sub 6 gigahertz (GHz)” bands such as 3.5 GHz, but also in “Above 6 GHz” bands referred to as millimeter wave (mmWave) including 28 GHz and 39 GHz. In addition, it has been considered to implement 6th generation (6G) mobile communication technologies (referred to as Beyond 5G systems) in terahertz (THz) bands (for example, 95 GHz to 3 THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies. At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive multiple-input multiple-output (MIMO) for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BandWidth Part (BWP), new channel coding methods such as a Low Density Parity Check (LDPC) code for large amount of data transmission and a polar code for highly reliable transmission of control information, layer 2 (L2) pre-processing, and network slicing for providing a dedicated network specialized to a specific service. Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical (PHY) layer standardization regarding technologies such as Vehicle-to-everything (V2X) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, New Radio Unlicensed (NR-U) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, new radio (NR) user equipment (UE) Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning. Moreover, there has been ongoing standardization in air interface architecture/protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, Integrated Access and Backhaul (IAB) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and Dual Active Protocol Stack (DAPS) handover, and two-step random access for simplifying random access procedures (2-step random access channel (RACH) for NR). There also has been ongoing standardization in system architecture/service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions. As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communicati