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US-20260129522-A1 - METHOD AND APPARATUS FOR TRANSFER OF UE INFORMATION FOR RRC PROCEDURE IN A WIRELESS COMMUNICATION SYSTEM

US20260129522A1US 20260129522 A1US20260129522 A1US 20260129522A1US-20260129522-A1

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. Specifically, the disclosure related to a first method, for a first base station, for transferring a User Equipment (UE) context from the first base station to a second base station. The first method comprises: in response to obtaining a prediction that a connection of the UE to the first base station will be disconnected, transmitting, to the second base station and before the connection of the UE to the first base station is disconnected, information for performing a Radio Resource Control (RRC) procedure for establishing a connection between the UE and the second base station. There is disclosed a second method, for a second base station, for transferring a User Equipment (UE) context from a first base station to the second base station. The second method comprises: receiving, from the first base station and before a connection of the UE to the first base station is disconnected, information for performing a Radio Resource Control (RRC) procedure for establishing a connection between the UE and the second base station; receiving, from the UE, a message requesting the RRC procedure; and using the received information for performing the RRC procedure.

Inventors

  • Jonas SEDIN
  • Chadi KHIRALLAH

Assignees

  • SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date
20260507
Application Date
20231016
Priority Date
20221102

Claims (15)

  1. 1 . A method performed by a first base station, for transferring a user equipment (UE) context from the first base station to a second base station in a wireless communication system, the method comprising: in response to obtaining a prediction that a connection of the UE to the first base station will be disconnected, transmitting, to the second base station and before the connection of the UE to the first base station is disconnected, information for performing a Radio Resource Control (RRC) procedure for establishing a connection between the UE and the second base station.
  2. 2 . A method of claim 1 , wherein obtaining the prediction that the connection of the UE to the first base station will be disconnected comprises obtaining a prediction that at least one of Radio Link Failure (RLF), handover, or suspension of RRC connection will occur.
  3. 3 . A method of claim 2 , wherein the RRC procedure comprises at least one of RRC Reestablishment, or RRC Resume, wherein the obtaining the prediction further comprises determining, by the first base station, the prediction, or receiving the prediction from the UE or another network entity, wherein obtaining the prediction comprises predicting that the connection of the UE to the first base station will be disconnected based on information on the relative movement between the UE and a cell or coverage area of the first base station, wherein the first base station is a Non-Terrestrial Network (NTN) base station, and wherein the information on the relative movement comprises information on movement of the cell or coverage area based on movement of the NTN base station, and wherein the information on the relative movement comprises information on movement of the UE.
  4. 4 . A method of claim 1 , wherein the information for performing the RRC procedure comprises a UE context for the UE, and wherein the information for performing a Radio Resource Control (RRC) procedure is transmitted in at least one of a HANDOVER REQUEST message, and RETRIEVE UE CONTEXT RESPONSE message.
  5. 5 . A method of claim 1 , the method further comprising: transmitting, to the UE, an indication that the information for performing the Radio Resource Control (RRC) procedure has been transmitted to the second base station; transmitting, to each of one or more base stations including the second base station, a handover request message; receiving one or more handover request acknowledgement messages in response to the handover request messages; and transmitting, to the UE and before the connection of the UE to the first base station is disconnected, information indicating which of the base stations transmitted a handover request acknowledgement message, wherein the UE performs a cell measurement for certain base stations based on the transmitted information.
  6. 6 . A method performed by a second base station, for transferring a User Equipment (UE) context from a first base station to the second base station in a wireless communication system, the method comprising: receiving, from the first base station and before a connection of the UE to the first base station is disconnected, information for performing a Radio Resource Control (RRC) procedure for establishing a connection between the UE and the second base station; receiving, from the UE, a message requesting the RRC procedure; and using the received information for performing the RRC procedure.
  7. 7 . A method of claim 6 , the method further comprising: deleting, by the second base station, the received information a certain time period after receiving the information; and transmitting a message indicating that the information for performing the RRC procedure has been received by the second base station.
  8. 8 . A method of claim 7 , wherein the message requesting the RRC procedure is at least one of an RRC Re-establishment request message, or a RRC Resume request message.
  9. 9 . A method of claim 6 , the method further comprising: transmitting a message requesting to receive information for performing the RRC procedure; and in response to receiving the information for performing the RRC procedure, determining whether to accept the information.
  10. 10 . A method of claim 6 , wherein the information for performing the RRC procedure comprises a UE context for the UE.
  11. 11 . A method of claim 6 , the method further comprising: in response to receiving the information for performing the RRC procedure, determining whether to accept the information; transmitting a message indicating whether the information for performing the RRC procedure is accepted; and transmitting a message indicating whether the information for performing the RRC procedure is rejected.
  12. 12 . A method performed by a User Equipment (UE), for connecting to a base station in a wireless communication system, the method comprising: receiving, from a first base station to which the UE is, or has been, connected, an indication that information for performing a Radio Resource Control (RRC) procedure has been transmitted to (and/or accepted by) one or more second base stations; disconnecting from the first base station; selecting another base station based on the received indication; and connecting to the selected other base station.
  13. 13 . A method of claim 12 , wherein the other base station is selected from among the second base stations, wherein the other base station is not selected from among the second base stations if none of the second base stations are available, wherein the other base station is selecting according to a scheme that prioritises the second base stations.
  14. 14 . A method of claim 12 , the method further comprising, based on the received indication, performing a cell measurement for each of one or more cells corresponding to one or more of the second base stations.
  15. 15 . A method of claim 12 , wherein the cell measurements are performed before the UE disconnects from the first base station.

Description

TECHNICAL FIELD The present disclosure relates generally to wireless communication systems and, more specifically, the present disclosure relates to one or more techniques for transferring, between network access points, User Equipment (UE) information for performing a Radio Resource Control (RRC) procedure. For example, certain examples of the present disclosure provide one or more techniques for transferring a UE context from a first base station to a second base station in a 3rd Generation Partnership Project (3GPP) 5th Generation (5G) New Radio (NR) network. 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 6 GHz” bands such as 3.5 GHz, but also in “Above 6 GHz” bands referred to as mmWave including 28 GHz and 39 GHz. In addition, it has been considered to implement 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 MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mm Wave, 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 un-available, 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 mobil