EP-4742755-A1 - METHOD AND DEVICE FOR UPDATING UPLINK SYNCHRONIZATION IN WIRELESS COMMUNICATION SYSTEM

EP4742755A1EP 4742755 A1EP4742755 A1EP 4742755A1EP-4742755-A1

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. A method performed by a user equipment (UE) in a wireless communication system, according to various embodiments of the present disclosure, may comprise the steps of: receiving, from a base station, a medium access control (MAC) control element (CE) for indicating the state of a cross-remote radio head (RRH) transmission configuration indicator (TCI); receiving, from the base station, a physical downlink control channel (PDCCH) according to the TCI state indicated by the MAC CE; and performing an uplink (UL) timing adjustment after switching to the TCI state on the basis of the MAC CE, wherein the MAC CE may include an identifier (ID) of the TCI state, and an indicator indicating the UL timing adjustment.

Inventors

JIN, SEUNGRI
LEE, Taeseop

Assignees

Samsung Electronics Co., Ltd.

Dates

Publication Date: 20260513
Application Date: 20240801

Claims (15)

A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: receive, from a base station, a medium access control (MAC) control element (CE) for indicating a cross-remote radio head (RRH) transmission configuration indicator (TCI) state; receive, from the base station, a physical downlink control channel (PDCCH) according to a TCI state indicated by the MAC CE; and based on the MAC CE, perform an uplink (UL) timing adjustment after switching to the TCI state, and wherein the MAC CE includes an identifier (ID) of the TCI state and an indicator indicating the UL timing adjustment.
The UE of claim 1, wherein the indicator indicating the UL timing adjustment indicates whether to apply the UL timing adjustment without identifying a threshold value for a downlink (DL) timing difference.
The UE of claim 1, wherein a first octet and a second octet of the MAC CE include information associated with the TCI state, wherein a third octet of the MAC CE includes the indicator indicating the UL timing adjustment, and wherein the indicator indicating the UL timing adjustment comprises 1 bit.
The UE of claim 1, wherein the controller is further configured to: transmit, to the base station, capability information indicating whether the UE supports one shot UL timing adjustment; and receive, from the base station, information for configuring information for a high speed scenario.
A base station in a wireless communication system, the base station comprising: a transceiver; and a controller coupled to the transceiver, wherein the controller is configured to: transmit, to a user equipment (UE), a medium access control (MAC) control element (CE) for indicating a cross-remote radio head (RRH) transmission configuration indicator (TCI) state; and transmit, to the UE, a physical downlink control channel (PDCCH) according to a TCI state indicated by the MAC CE, wherein the MAC CE includes an identifier (ID) of the TCI state and an indicator indicating an UL timing adjustment, and wherein the UL timing adjustment after switching to the TCI state is based on the MAC CE.
The base station of claim 5, wherein the indicator indicating the UL timing adjustment indicates whether to apply the UL timing adjustment without identifying a threshold value for a downlink (DL) timing difference.
The base station of claim 6, wherein a first octet and a second octet of the MAC CE include information associated with the TCI state, wherein a third octet of the MAC CE includes the indicator indicating the UL timing adjustment, and wherein the indicator indicating the UL timing adjustment comprises 1 bit.
The base station of claim 5, wherein the controller is further configured to: receive, from the UE, capability information indicating whether the UE supports one shot UL timing adjustment; and transmit, to the UE, information for configuring information for a high speed scenario.
A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a base station, a medium access control (MAC) control element (CE) for indicating a cross-remote radio head (RRH) transmission configuration indicator (TCI) state; receiving, from the base station, a physical downlink control channel (PDCCH) according to a TCI state indicated by the MAC CE; and based on the MAC CE, performing an uplink (UL) timing adjustment after switching to the TCI state, wherein the MAC CE includes an identifier (ID) of the TCI state and an indicator indicating the UL timing adjustment.
The method of claim 9, wherein the indicator indicating the UL timing adjustment indicates whether to apply the UL timing adjustment without identifying a threshold value for a downlink (DL) timing difference.
The method of claim 9, wherein a first octet and a second octet of the MAC CE include information associated with the TCI state, wherein a third octet of the MAC CE includes the indicator indicating the UL timing adjustment, and wherein the indicator indicating the UL timing adjustment comprises 1 bit.
The method of claim 9, further comprising: transmitting, to the base station, capability information indicating whether the UE supports one shot UL timing adjustment; and receiving, from the base station, information for configuring information for a high speed scenario.
A method performed by a base station in a wireless communication system, the method comprising: transmitting, to a user equipment (UE), a medium access control (MAC) control element (CE) for indicating a cross-remote radio head (RRH) transmission configuration indicator (TCI) state; and transmitting, to the UE, a physical downlink control channel (PDCCH) according to a TCI state indicated by the MAC CE, wherein the MAC CE includes an identifier (ID) of the TCI state and an indicator indicating an UL timing adjustment, and wherein the UL timing adjustment after switching to the TCI state is based on the MAC CE.
The method of claim 13, wherein the indicator indicating the UL timing adjustment indicates whether to apply the UL timing adjustment without identifying a threshold value for a downlink (DL) timing difference.
The method of claim 13, wherein a first octet and a second octet of the MAC CE include information associated with the TCI state, wherein a third octet of the MAC CE includes the indicator indicating the UL timing adjustment, and wherein the indicator indicating the UL timing adjustment comprises 1 bit.

Description

[Technical Field] The disclosure relates to a wireless communication system and, more particularly, to operations of a UE and a base station in a wireless communication system. Specifically, the disclosure relates to a method and an apparatus for updating uplink synchronization together when changing a beam inside a cell in a wireless communication system. [Background Art] 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 (THz) 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