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EP-4740587-A1 - METHOD AND APPARATUR FOR A UE-BASED TIMING ADVANCE MEASUREMENT IN A WIRELESS COMMUNICATION SYSTEM

EP4740587A1EP 4740587 A1EP4740587 A1EP 4740587A1EP-4740587-A1

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A User equipment (UE) transmits, to a base station, a capability information indicating whether the UE supports UE-based timing advance measurement, and receives, from the base station, an indication indicating whether UE-based timing advance measurement is enabled for a candidate cell for layer 1/layer 2 triggered mobility (LTM). The UE configures UE-based timing advance measurement for the candidate cell for LTM based on the indication, and performs UE-based timing advance measurement for the candidate cell for LTM. The UE receives a cell switch command from the base station. When a valid timing advance is not included in the cell switch command, the UE switches to the candidate cell for LTM by applying a timing advance measured by the UE. When the valid timing advance is included in the cell switch command, the UE switches to the candidate cell for LTM by applying the valid timing advance.

Inventors

  • LENG, Shiyang
  • AGIWAL, ANIL
  • FARAG, Emad Nader

Assignees

  • Samsung Electronics Co., Ltd.

Dates

Publication Date
20260513
Application Date
20240805

Claims (15)

  1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a base station, layer 1/layer 2 (L1/L2) triggered mobility (LTM) information associated with measuring a timing advance (TA) for an LTM candidate cell; based on the LTM information, acquring a TA value for the LTM candidate cell by a measurement; receiving, from the base station, an LTM cell switch command; and based on the LTM cell switch command, performing an LTM cell switch by applying the TA value acquired by the measurement.
  2. The method of claim 1, wherein the TA value acquired by the measurement is applied, in case that the no valid TA value is provided in the LTM cell switch command.
  3. The method of claim 1, the method further comprising: starting a time alignment timer associated with a timing advance group.
  4. The method of claim 1, wherein the LTM information is associated with configuring a UE-based TA measurement for the LTM candidate cell.
  5. A method performed by a base station in a wireless communication system, the method comprising: transmitting, to a user equipment (UE), layer 1/layer 2 (L1/L2) triggered mobility (LTM) information associated with measuring a timing advance (TA) for an LTM candidate cell; and transmitting, to the UE, an LTM cell switch command, wherein a TA value for the LTM candidate cell is acquired by a measurement based on the LTM information, and wherein an LTM cell switch is performed by applying the TA value acquired by the measurement based on the LTM cell switch command.
  6. The method of claim 5, wherein the TA value acquired by the measurement is applied, in case that the no valid TA value is provided in the LTM cell switch command.
  7. The method of claim 5, wherein a time alignment timer associated with a timing advance group is started after applying the TA value.
  8. The method of claim 5, wherein the LTM information is associated with configuring a UE-based TA measurement for the LTM candidate cell.
  9. A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a controller configured to: receive, from a base station, layer 1/layer 2 (L1/L2) triggered mobility (LTM) information associated with measuring a timing advance (TA) for an LTM candidate cell, based on the LTM information, acqure a TA value for the LTM candidate cell by a measurement, receive, from the base station, an LTM cell switch command, and based on the LTM cell switch command, perform an LTM cell switch by applying the TA value acquired by the measurement.
  10. The UE of claim 9, wherein the TA value acquired by the measurement is applied, in case that the no valid TA value is provided in the LTM cell switch command.
  11. The UE of claim 9, wherein the controller is further configured to: start a time alignment timer associated with a timing advance group.
  12. The UE of claim 9, wherein the LTM information is associated with configuring a UE-based TA measurement for the LTM candidate cell.
  13. A base station in a wireless communication system, the base station comprising: a transceiver; and a controller configured to: transmit, to a user equipment (UE), layer 1/layer 2 (L1/L2) triggered mobility (LTM) information associated with measuring a timing advance (TA) for an LTM candidate cell, and transmit, to the UE, an LTM cell switch command, wherein a TA value for the LTM candidate cell is acquired by a measurement based on the LTM information, and wherein an LTM cell switch is performed by applying the TA value acquired by the measurement based on the LTM cell switch command.
  14. The base station of claim 13, wherein the TA value acquired by the measurement is applied, in case that the no valid TA value is provided in the LTM cell switch command.
  15. The base station of claim 13, wherein a time alignment timer associated with a timing advance group is started after applying the TA value, and wherein the LTM information is associated with configuring a UE-based TA measurement for the LTM candidate cell.

Description

METHOD AND APPARATUR FOR A UE-BASED TIMING ADVANCE MEASUREMENT IN A WIRELESS COMMUNICATION SYSTEM This disclosure relates generally to a wireless communication system, and more particularly to, for example, but not limited to, mobility in a wireless communication system. 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 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz 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 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 BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, 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 layer standardization regarding technologies such as V2X (Vehicle-to-everything) 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, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR 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, IAB (Integrated Access and Backhaul) 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 DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step 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 AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) 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 communication. Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum),