Method and apparatus for processing measurement and evaluation for conditional handover in next-generation mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transfer rates. A method of user equipment (UE) in a wireless communication system, according to an embodiment of the present disclosure, may comprise the steps of: receiving, from a base station, a radio resource control (RRC) reconfiguration message including configuration information for conditional handover (CHO) via a candidate secondary cell group (SCG); when an SCG connection failure (SCG failure) occurs in the UE, transmitting SCG failure information to the base station; and when the SCG failure information is transmitted, stopping measurement of a candidate primary secondary cell (PSCell).

Description

Method and device for processing measurement and evaluation for conditional handover in next-generation mobile communication systems

[0001] The present disclosure relates to a technology for controlling conditional handover by a terminal in a mobile communication system.

[0002] Additionally, the present disclosure relates to a method and device for sequentially performing conditional PSCell addition and change.

[0003] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0004] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0005] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0006] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0007] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0008] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0009] As described above and with the development of mobile communication systems, various services have become available, and methods for effectively providing these services are required.

[0010] The present disclosure proposes a technology for controlling conditional handover in a mobile communication system during a process of connection failure between a terminal and a base station.

[0011] In addition, the present disclosure proposes a method and device for performing SCPAC (subsequent conditional PSCell addition and change) in a next-generation wireless communication system.

[0012] More specifically, to perform SCPAC on a terminal, the conditions for conditional PSCell addition and change, as well as the target cell settings, must be changed for each PSCell change. The present disclosure proposes a method and device for the network to signal this information to the terminal.

[0013] The technical problems to be achieved in the embodiments of the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0014] In a wireless communication system according to one embodiment of the present disclosure, a method of a UE (user equipment) may include an operation of receiving an RRC (radio resource control) message including configuration information for a conditional handover for a target Pcell (primary cell) and a conditional Pscell (primary secondary cell) change from a network node; an operation of transmitting SCG (secondary cell group) failure information to the network node when an SCG failure occurs; and an operation of stopping condition evaluation and measurement for a candidate target Pcell and the candidate target Pscell based on the RRC message.

[0015] In a wireless communication system according to one embodiment of the present disclosure, a method of a UE (user equipment) may include an operation of receiving an RRC (radio resource control) message including configuration information for a conditional handover for a target Pcell (primary cell) and a conditional Pscell (primary secondary cell) change from a network node; an operation of transmitting MCG (master cell group) failure information to the network node when an MCG failure occurs; and an operation of stopping condition evaluation and measurement for a candidate target Pcell and the candidate target Pscell based on the RRC message.

[0016] In a wireless communication system according to one embodiment of the present disclosure, a UE (user equipment) may include a transceiver; and a control unit. The control unit may receive an RRC (radio resource control) message including configuration information for a conditional handover for a target Pcell (primary cell) and a conditional Pscell (primary secondary cell) change from a network node, control to transmit SCG (secondary cell group) failure information to the network node when an SCG failure occurs, and stop condition evaluation and measurement for a candidate target Pcell and the candidate target Pscell based on the RRC message.

[0017] In a wireless communication system according to one embodiment of the present disclosure, a UE (user equipment) may include a transceiver; and a control unit. The control unit may receive an RRC (radio resource control) message including configuration information for a conditional handover for a target Pcell (primary cell) and a conditional Pscell (primary secondary cell) change from a network node, and, when an MCG (master cell group) failure occurs, control to transmit MCG failure information to the network node, and may stop condition evaluation and measurement for a candidate target Pcell and the candidate target Pscell based on the RRC message.

[0018] A method performed by a terminal in a wireless communication system according to one embodiment of the present disclosure comprises the steps of: receiving, from a source base station, a radio resource control (RRC) message including subsequent PCELL add and change (SCPAC) configuration information; changing to a target PSCell that satisfies a PSCell addition and change condition based on the SCPAC configuration information; and determining, based on the SCPAC configuration information, whether a PSCell addition and change condition is satisfied with the changed target PSCell as a source cell.

[0019] Embodiments of the present disclosure can efficiently control conditional handover even in a process in which a terminal fails to connect to a base station in a mobile communication system.

[0020] According to one embodiment of the present disclosure, a terminal can perform continuous pscell addition and change through a single signal to the network.

[0021] The effects that can be obtained from the present disclosure are not limited to the effects mentioned in the various embodiments, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0022] FIG. 1 is a diagram illustrating the structure of an LTE system according to an embodiment of the present disclosure.

[0023] FIG. 2 is a diagram illustrating a wireless protocol structure of an LTE system according to an embodiment of the present disclosure.

[0024] FIG. 3 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0025] FIG. 4 is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0026] FIG. 5 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0027] FIG. 6 is a block diagram showing the configuration of an NR base station according to an embodiment of the present disclosure.

[0028] FIG. 7 illustrates a measurement operation of a terminal according to an SCG Failure Information procedure according to an embodiment of the present disclosure.

[0029] FIG. 8 illustrates an evaluation operation of a terminal according to an MCG Failure Information procedure according to an embodiment of the present disclosure.

[0030] FIG. 9 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to one embodiment of the present disclosure.

[0031] FIG. 10 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0032] FIG. 11 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0033] FIG. 12 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0034] FIG. 13 is a flowchart illustrating a flow for performing a subsequent conditional PSCell addition and change (SCPAC) operation of a terminal according to an embodiment of the present disclosure.

[0035] The operating principles of the present invention will be described in detail below with reference to the attached drawings. In the following description of the present invention, detailed descriptions of known functions or components will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0036] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided for convenience of explanation. Therefore, the present invention is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0037] Hereinafter, the base station is an entity that performs resource allocation of the terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although the LTE or LTE-A system may be described below as an example, the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in a system to which the embodiments of the present disclosure may be applied, and 5G below may also be a concept that includes existing LTE, LTE-A, and other similar services. Furthermore, the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure. It will be appreciated that each block of the processing flow diagrams and combinations of the flow diagrams can be executed by computer program instructions.

[0038] These computer program instructions may be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, so that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for performing the functions described in the flowchart block(s). These computer program instructions may also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing apparatus to implement functions in a particular manner, so that the instructions stored in the computer-available or computer-readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the flowchart block(s). The computer program instructions may also be installed on a computer or other programmable data processing apparatus, so that a series of operational steps are performed on the computer or other programmable data processing apparatus to create a computer-implemented process, so that the instructions executing on the computer or other programmable data processing apparatus can provide steps for performing the functions described in the flowchart block(s).

[0039] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function. In this case, the term '~unit' used in the present embodiment means software or a hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the '~unit' may perform certain roles. However, the '~unit' is not limited to software or hardware. The '~unit' may be configured to be on an addressable storage medium and may be configured to execute one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to reproduce one or more CPUs within a device or a secure multimedia card. Also, in an embodiment, the '~ unit' may include one or more processors.

[0040] For convenience of explanation, the present invention uses terms and names defined in the 5GS and NR standards, which are standards defined by the 3rd Generation Partnership Project (3GPP) among the existing communication standards. However, the present invention is not limited to the above terms and names and can be equally applied to wireless communication networks that follow other standards. For example, the present invention can be applied to the 3GPP 5GS / NR (5th generation mobile communication standard).

[0041] FIG. 1 is a diagram illustrating the structure of an LTE system according to one embodiment of the present disclosure.

[0042] Referring to FIG. 1, as illustrated, a wireless access network of an LTE system may be composed of next-generation base stations (Evolved Node Bs, hereinafter referred to as ENBs, Node Bs or base stations) (105, 110, 115, 120), a mobility management entity (MME) (125) and an S-GW (130, Serving-Gateway). A user equipment (UE or terminal) (135) may access an external network through the ENBs (105 to 120) and the S-GW (130).

[0043] In Fig. 1, ENBs (105 to 120) may correspond to existing Node Bs of a UMTS system. ENBs are connected to UEs (135) via a wireless channel and may perform more complex roles than existing Node Bs. In an LTE system, all user traffic, including real-time services such as VoIP (Voice over IP) via the Internet Protocol, can be serviced through a shared channel. Therefore, a device that collects status information such as buffer status, available transmission power status, and channel status of UEs and performs scheduling is required, and ENBs (105 to 120) may be responsible for this. One ENB can typically control multiple cells. For example, in order to implement a transmission rate of 100 Mbps, an LTE system may use, for example, Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology in a 20 MHz bandwidth. In addition, an adaptive modulation and coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel status of the terminal can be applied. The S-GW (130) is a device that provides a data bearer and can create or remove a data bearer according to the control of the MME (125). The MME (125) is a device that is responsible for various control functions as well as mobility management functions for the terminal (135) and can be connected to multiple base stations.

[0044] FIG. 2 is a diagram illustrating a wireless protocol structure of an LTE system according to one embodiment of the present disclosure.

[0045] Referring to FIG. 2, the wireless protocol of the LTE system may be composed of a Packet Data Convergence Protocol (PDCP) (205, 240), a Radio Link Control (RLC) (210, 235), and a Medium Access Control (MAC) (215, 230) in the terminal and the ENB, respectively.

[0046] PDCP (205, 240) can handle operations such as IP header compression / decompression. The main functions of PDCP can be summarized as follows.

[0047] - Header compression and decompression (ROHC only)

[0048] - User data transfer function

[0049] - In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

[0050] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0051] - Duplicate detection function (Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

[0052] - Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of ​​PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

[0053] - Encryption and decryption functions (Ciphering and deciphering)

[0054] - Timer-based SDU discard in uplink.

[0055] Radio Link Control (RLC) (210, 235) can perform ARQ operations, etc. by reconfiguring PDCP packet data units (PDUs) to an appropriate size. The main functions of RLC (210, 235) can be summarized as follows.

[0056] - Data transfer function (Transfer of upper layer PDUs)

[0057] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0058] - Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

[0059] - Re-segmentation of RLC data PDUs (only for AM data transfer)

[0060] - Reordering of RLC data PDUs (only for UM and AM data transfer)

[0061] - Duplicate detection (only for UM and AM data transfer)

[0062] - Error detection function (Protocol error detection (only for AM data transfer))

[0063] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

[0064] - RLC re-establishment function

[0065] MAC (215, 230) is connected to multiple RLC layer devices configured in a single terminal, and can perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC (215, 230) can be summarized as follows.

[0066] - Mapping function (Mapping between logical channels and transport channels)

[0067] - Multiplexing and demultiplexing function (Multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels)

[0068] - Scheduling information reporting function

[0069] - HARQ function (Error correction through HARQ)

[0070] - Priority handling between logical channels of one UE

[0071] - Priority handling between UEs by means of dynamic scheduling

[0072] - MBMS service identification function

[0073] - Transport format selection function

[0074] - Padding function

[0075] The physical layer (220, 225) can perform an operation of channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and transmitting them to a higher layer.

[0076] FIG. 3 is a diagram illustrating the structure of a next-generation mobile communication system according to one embodiment of the present disclosure.

[0077] Referring to FIG. 3, a wireless access network of a next-generation mobile communication system (hereinafter referred to as NR or 5g) may be composed of a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (310) and a next-generation radio core network (New Radio Core Network, NR CN) (305). A next-generation radio user equipment (NR UE or terminal) (315) may access an external network through the NR gNB (310) and the NR CN (305).

[0078] In Fig. 3, the NR gNB (310) may correspond to an eNB (Evolved Node B) of an LTE system. The NR gNB is connected to the NR UE (315) via a wireless channel and may provide a service superior to that of the existing Node B. In the next-generation mobile communication system, all user traffic may be serviced through a shared channel. Therefore, a device is required that collects status information such as the buffer status of UEs, available transmission power status, and channel status and performs scheduling, and the NR gNB (310) may be responsible for this scheduling.

[0079] A single NR gNB (310) can control multiple cells. In the next-generation mobile communication system, a bandwidth exceeding the general maximum bandwidth may be applied to implement ultra-high-speed data transmission compared to general LTE. In addition, beamforming technology may be additionally incorporated using orthogonal frequency division multiplexing (OFDM) as a wireless access technology. In addition, an adaptive modulation and coding (AMC) method that determines a modulation scheme and channel coding rate according to the channel condition of the terminal (315) may be applied.

[0080] The NR CN (305) can perform functions such as mobility support, bearer setup, and QoS setup. The NR CN (305) is a device that handles various control functions as well as mobility management functions for the terminal (315) and can be connected to multiple base stations. In addition, the next-generation mobile communication system can be linked with the LTE system, and the NR CN (305) can be connected to the MME (325) through a network interface. The MME (325) can be connected to the eNB (330), which is an LTE base station.

[0081] FIG. 4 is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to one embodiment of the present disclosure.

[0082] Referring to FIG. 4, the wireless protocol of the next-generation mobile communication system may be composed of NR Service Data Adaptation Protocol (SDAP) (401, 445), NR PDCP (405, 440), NR RLC (410, 435), NR MAC (415, 430), and NR PHY (420, 425) in the terminal and NR base station, respectively.

[0083] The main functions of NR SDAP (401, 445) may include some or all of the following functions:

[0084] - Transfer of user plane data

[0085] - Mapping function between QoS flow and data bearer for both DL and UL

[0086] - QoS flow ID marking function for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0087] - Ability to map relective QoS flow to data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0088] For an SDAP layer device, a terminal can be configured by a Radio Resource Control (RRC) message for each PDCP layer device, per bearer, or per logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device. When the SDAP header is configured, the terminal can instruct the terminal to update or reset the mapping information for the QoS flow and data bearer of the uplink and downlink by using a 1-bit indicator for reflecting the Non-Access Stratum (NAS) Quality of Service (QoS) in the SDAP header (NAS reflective QoS) and a 1-bit indicator for reflecting the Access Stratum (AS) QoS in the SDAP header. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. to support a smooth service.

[0089] The main functions of NR PDCP (405, 440) may include some or all of the following functions:

[0090] - Header compression and decompression (ROHC only)

[0091] - User data transfer function

[0092] - In-sequence delivery of upper layer PDUs

[0093] - Out-of-sequence delivery of upper layer PDUs

[0094] - PDCP PDU reordering for reception

[0095] - Duplicate detection of lower layer SDUs

[0096] - Retransmission function (Retransmission of PDCP SDUs)

[0097] - Encryption and decryption functions (Ciphering and deciphering)

[0098] - Timer-based SDU discard in uplink.

[0099] In the above, the reordering function of the NR PDCP device may refer to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP SN (sequence number). The reordering function of the NR PDCP device may include a function of transmitting data to an upper layer in the reordered order, or a function of transmitting data directly without considering the order, a function of recording lost PDCP PDUs by reordering the order, a function of reporting a status of lost PDCP PDUs to the transmitting side, and a function of requesting retransmission of lost PDCP PDUs.

[0100] The main functions of NR RLC (410, 435) may include some or all of the following functions.

[0101] - Data transfer function (Transfer of upper layer PDUs)

[0102] - In-sequence delivery of upper layer PDUs

[0103] - Out-of-sequence delivery of upper layer PDUs

[0104] - ARQ function (Error Correction through ARQ)

[0105] - Concatenation, segmentation and reassembly of RLC SDUs

[0106] - Re-segmentation of RLC data PDUs

[0107] - Reordering of RLC data PDUs

[0108] - Duplicate detection function

[0109] - Protocol error detection

[0110] - RLC SDU discard function

[0111] - RLC re-establishment function

[0112] In the above, the in-sequence delivery function of the NR RLC device may refer to the function of sequentially delivering RLC SDUs received from the lower layer to the upper layer. If a single RLC SDU is originally received divided into multiple RLC SDUs, the in-sequence delivery function of the NR RLC device may include the function of reassembling and delivering them.

[0113] The in-sequence delivery function of the NR RLC device may include a function to reorder received RLC PDUs based on the RLC SN (sequence number) or PDCP SN (sequence number), a function to record lost RLC PDUs by reordering them, a function to report status of lost RLC PDUs to the transmitter, and a function to request retransmission of lost RLC PDUs.

[0114] The in-sequence delivery function of the NR RLC device may include a function to sequentially deliver only the RLC SDUs up to the lost RLC SDU to the upper layer when there is a lost RLC SDU.

[0115] The in-sequence delivery function of the NR RLC device may include a function to deliver to the upper layer in sequence all RLC SDUs received before a predetermined timer starts if there are lost RLC SDUs and a predetermined timer has expired.

[0116] The in-sequence delivery function of the NR RLC device may include a function to deliver all RLC SDUs received so far to the upper layer in order if a predetermined timer has expired, even if there are lost RLC SDUs.

[0117] An NR RLC device can process RLC PDUs in the order they are received and deliver them to an NR PDCP device, regardless of the order of the sequence number (out-of-sequence delivery).

[0118] When an NR RLC device receives a segment, it can receive segments that are stored in a buffer or will be received later, reconstruct them into a complete RLC PDU, and then transmit them to the NR PDCP device.

[0119] The NR RLC layer may not include concatenation functionality, and the functionality may be performed by the NR MAC layer or replaced by the multiplexing functionality of the NR MAC layer.

[0120] In the above, the out-of-sequence delivery function of the NR RLC device may refer to the function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of the order. The out-of-sequence delivery function of the NR RLC device may include the function of reassembling and delivering the RLC SDUs when an original RLC SDU is received fragmented into multiple RLC SDUs. The out-of-sequence delivery function of the NR RLC device may include the function of storing and arranging the RLC SN or PDCP SN of the received RLC PDUs to record the lost RLC PDUs.

[0121] The NR MAC (415, 430) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of the NR MAC (415, 430) can include some or all of the following functions.

[0122] - Mapping function (Mapping between logical channels and transport channels)

[0123] - Multiplexing / demultiplexing of MAC SDUs

[0124] - Scheduling information reporting function

[0125] - HARQ function (Error correction through HARQ)

[0126] - Priority handling between logical channels of one UE

[0127] - Priority handling between UEs by means of dynamic scheduling

[0128] - MBMS service identification function

[0129] - Transport format selection function

[0130] - Padding function

[0131] The NR PHY layer (420, 425) can perform operations of channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and transmitting them to a higher layer.

[0132] FIG. 5 is a block diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0133] Referring to FIG. 5, the terminal includes an RF (Radio Frequency) processing unit (510), a baseband processing unit (520), a storage unit (530), and a control unit (540).

[0134] The RF processing unit (510) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (510) up-converts the baseband signal provided from the baseband processing unit (520) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (510) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In FIG. 5, only one antenna is illustrated for convenience of explanation, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit (510) may include multiple RF chains. Furthermore, the RF processing unit (510) may perform beamforming. For the above beamforming, the RF processing unit (510) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit can perform MIMO and receive multiple layers when performing the MIMO operation.

[0135] The baseband processing unit (520) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (520) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (520) can restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (510). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (520) can generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit (520) divides the baseband signal provided from the RF processing unit (510) into OFDM symbol units, restores signals mapped to subcarriers through FFT (fast Fourier transform), and then restores the received bit string through demodulation and decoding.

[0136] The baseband processing unit (520) and the RF processing unit (510) may transmit and / or receive signals according to embodiments of the present disclosure. The baseband processing unit (520) and the RF processing unit (510) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a transceiver. At least one of the baseband processing unit (520) and the RF processing unit (510) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (520) and the RF processing unit (510) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band and a millimeter wave (mm wave) (e.g., 60GHz) band.

[0137] The storage unit (530) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (530) can store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit (530) provides the stored data at the request of the control unit (540).

[0138] The control unit (540) controls the overall operations of the terminal. For example, the control unit (540) transmits and receives signals through the baseband processing unit (520) and the RF processing unit (510). In addition, the control unit (540) records and reads data in the storage unit (540). For this purpose, the control unit (540) may include at least one processor. For example, the control unit (540) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0139] FIG. 6 is a block diagram showing the configuration of an NR base station according to an embodiment of the present disclosure.

[0140] Referring to FIG. 6, the base station may be configured to include an RF processing unit (610), a baseband processing unit (620), a backhaul communication unit (630), a storage unit (640), and a control unit (650).

[0141] The RF processing unit (610) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (610) up-converts the baseband signal provided from the baseband processing unit (620) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (610) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In Fig. 6, only one antenna is illustrated for convenience of explanation, but the base station may be equipped with multiple antennas.

[0142] In addition, the RF processing unit (610) may include multiple RF chains. Furthermore, the RF processing unit (610) may perform beamforming. For the beamforming, the RF processing unit (610) may adjust the phase and magnitude of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit (610) may perform a downlink MIMO operation by transmitting one or more layers.

[0143] The baseband processing unit (620) may perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (620) may generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (620) may restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (610). For example, in the case of OFDM, when transmitting data, the baseband processing unit (620) may generate complex symbols by encoding and modulating a transmission bit stream, map the complex symbols to subcarriers, and then configure OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (620) can divide the baseband signal provided from the RF processing unit (610) into OFDM symbol units, restore signals mapped to subcarriers through FFT operation, and then restore the received bit string through demodulation and decoding. The baseband processing unit (620) and the RF processing unit (610) can transmit and / or receive signals according to embodiments of the present disclosure. The baseband processing unit (620) and the RF processing unit (610) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, a wireless communication unit, or a transceiver.

[0144] The backhaul communication unit (630) may provide an interface for communicating with other nodes within the network. The backhaul communication unit (630) may convert a bit string transmitted from a primary base station to other nodes, such as auxiliary base stations or core networks, into a physical signal, and may convert a physical signal received from the other nodes into a bit string.

[0145] The storage unit (640) can store data such as basic programs, application programs, and configuration information for the operation of the main base station. In particular, the storage unit (640) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (640) can store information that serves as a basis for determining whether to provide or terminate multiple connections to a terminal. The storage unit (640) can provide stored data at the request of the control unit (650).

[0146] The control unit (650) can control the overall operations of the base station. For example, the control unit (650) can transmit and receive signals through the baseband processing unit (620) and the RF processing unit (610) or through the backhaul communication unit (6-30). In addition, the control unit (650) can record or read data in the storage unit (640). The control unit (650) can include at least one processor.

[0147] Meanwhile, the following abbreviations may be used in FIGS. 7 and 8.

[0148] S-MN: source master node

[0149] T-MN: target master node

[0150] S-Pcell: source primary cell

[0151] T-Pcell: target primary cell

[0152] S-SN: source secondary node

[0153] T-SN: target secondary node

[0154] S-PScell: source Pscell

[0155] T-PScell: target PScell

[0156] DC: dual connection

[0157] CHO: conditional handover

[0158] CHO with candidate SCG: UE function / feature on the simultaneous execution of conditional handover to target Pcell and conditional PScell ​​change to the target PScell

[0159] MO: measurement object

[0160] MCG: master cell group

[0161] SCG: secondary cell group

[0162] FIG. 7 illustrates a measurement operation of a terminal according to an SCG Failure Information procedure according to one embodiment of the present disclosure.

[0163] Referring to FIG. 7, in operation 701, the S-MN and the T-MN may prepare CHO with candidate SCGs. In operation 703, the UE may receive an RRCReconfiguration message including the CHO with candidate SCG configuration prepared in operation 701 from the S-MN.

[0164] According to one embodiment, the configuration of CHO with candidate SCG feature received by the terminal (or UE) from the network (or node) may include at least one of the following information:

[0165] - list of {candidate target Pcell settings and candidate target PScell ​​settings pair},

[0166] - list of {condition for target Pcell and condition for target pscell pair}

[0167] - conditional reconfiguration ID

[0168] According to one embodiment, each conditional reconfiguration ID may be associated with one {candidate target Pcell configuration and candidate target PScell ​​configuration pair} and {condition information associated with the candidate target Pcell and condition information pair associated with the candidate target PScell}.

[0169] According to one embodiment, the condition information may be a candidate target Pcell associated with a conditional reconfiguration ID and a condition related to the candidate target Pcell. When the Pcell-related condition and the Pcell-related condition are simultaneously satisfied, the terminal may perform a CHO with candidate SCG operation. The CHO with candidate SCG operation may be an operation of applying the candidate target Pcell configuration and the candidate target Pcell configuration associated with the conditional reconfiguration ID. According to one embodiment, the candidate target Pcell configuration and the candidate target Pcell configuration may be included in a single RRCReconfiguration message.

[0170] In one embodiment, the condition of each Pcell or Pscell may refer to a measurement ID (measurement ID or measID) set in the Pcell or Pscell, and the simultaneous satisfaction of multiple measurement IDs itself may constitute a condition for one Pcell or PScell.

[0171] In operation 705, the UE may perform measurements on candidate target Pcells, and in operation 707, the UE may perform measurements on candidate target PScells. Operations 705 and 707 correspond to measurements on MO performed by the UE in operation 709, and based on these measurements, the UE may begin evaluating conditions.

[0172] In operation 711, an SCG failure may occur between the UE and the S-SN. In one embodiment, the conditions for an SCG failure may be at least one of a radio link failure (RLF) in the SCG connection, a reconfigurationwithSync failure, a reconfiguration failure, a beam failure of the PSCell while the SCG is deactivated, and an integrity check failure indication from SCG lower layers concerning SRB3.

[0173] When a terminal has dual connection established with a Pcell of an S-MN and a pscell of an S-SN, it can receive a CHO with candidate SCG configuration from the network and perform measurement and condition evaluation operations for the related candidate target Pcell and Pscell.

[0174] According to one embodiment, the measurements corresponding to the candidate target Pcell and Pscell may be measurement objects indicated by each condition, and while performing the measurements, evaluations may be performed on specific events in the report configuration linked to the measurement object and condition information at the same time.

[0175] During the above operation, an SCG failure may occur due to a specific SCG-related operation. If an SCG Failure occurs, the UE may transmit SCG Failure Information to the S-MN in operation 713. According to one embodiment, the UE may include failure-related information in an SCG Failure Information message and transmit it to the network (or S-MN) using an MCG link.

[0176] In operation 715, the UE may not perform measurements on candidate target Pcells, and in operation 717, the UE may not perform measurements on candidate target PScells.

[0177] When the UE transmits an SCG Failure Information message to the MN, if CHO with candidate SCG is set, the UE may perform at least one of the following actions in step 719:

[0178] - In the CHO with candidate SCG setting, the evaluation operation of conditions corresponding to each candidate target pcell and pscell can be stopped.

[0179] - In the CHO with candidate SCG setting, the measurement operation being performed to evaluate the conditions corresponding to each candidate target pcell and pscell can be stopped.

[0180] The corresponding measurement operation may be a measurement operation for an MO associated with a measurement ID indicated as condition information corresponding to each candidate target pcell and pscell of the CHO with candidate SCG setting.

[0181] The reason for the above measurement suspension is that, in the case of the above measurement operation, in a situation where a failure has been reported to the network by the SCG failure information procedure, a separate indication from the network must be waited for again, and therefore the UE itself must not perform an operation of moving pcells and pscells, i.e., a CHO with candidate SCG operation.

[0182] In one embodiment, the following additional operations may be considered for the above measurement stop operation.

[0183] When the above measurement operation is stopped, exceptionally, if the pscell is set as a candidate target pscell during the setup of CHO with candidate SCG at the time when the SCG Failure Information operation is performed, the measurement stop for the current pscell may be excluded from the measurement stop operation.

[0184] ◆ The reason is that even if the SCG failure information procedure is performed, the terminal needs to maintain the measurement settings related to its current pscell, perform measurement operations, and log the measurement results when necessary, so that it can maintain the latest results when reporting a failure on SON / MDT in the future.

[0185] In case of stopping the above measurement operation, as another exception, if currently (i.e., when performing the SCG Failure Information procedure), the terminal is in a situation where configuration for a candidate target Pcell of a general CHO and measurement and evaluation thereof are being performed, the measurement for the candidate target Pcell of the CHO can be excluded from the target of the measurement stop operation according to the configuration of CHO with candidate SCG. That is, if the candidate target Pcell of the CHO is included among the candidate target Pcells of CHO with candidate SCG, the measurement is not stopped for the included candidate target Pcell.

[0186] ◆ For that reason, since CHO and CHO with candidate SCG can be independently set for target cells, in the case of candidate target pcell, the same pcell can be set, and in many cases, the network must also set CHO for the corresponding pcell to prevent cases where CHO with candidate SCG is not triggered and the state of the pcell deteriorates. In this case, if the pcell measurement is stopped due to SCG failure, the CHO to the corresponding candidate target pcell is also stopped, so the terminal must selectively avoid stopping the pcell measurement in this case.

[0187] In the case of the above-described optional Pcell measurement stop, in another embodiment, even if measurement for the same Pcell is instructed in CHO and CHO with candidate SCG, if a specific parameter is different in the MO indicating the Pcell, i.e., if it is instructed to be a different MO, the UE may stop the measurement for the candidate target Pcell on the CHO with candidate SCG. And the measurement for the candidate target Pcell on the CHO can still be performed. Since the measurement is performed on the MO here, if the MO is different, i.e., if a different parameter is set inside the MO, the measurement can be regarded as separate.

[0188] After the measurement operation is stopped, in operation 721, the UE may receive an RRCReconfiguration message including new configuration information from the S-MN. According to an embodiment, the configuration information may include the addition of a new SCG, i.e., configuration of a new pscell. According to an embodiment, the configuration information may include measurement configuration information in the corresponding pscell. According to an embodiment, the configuration information may include configuration of a new Cho with candidate SCG. The UE that receives the new configuration information may perform a measurement operation according to the configuration. When performing the measurement, measurement on the existing pscell may or may not be re-instructed.

[0189] FIG. 8 illustrates a CHO with candidate SCG evaluation operation of a terminal according to an MCG Failure Information procedure according to one embodiment of the present disclosure.

[0190] Referring to FIG. 8, operations 801 to 809 are substantially identical to operations 701 to 709 of FIG. 7, respectively, and thus a description thereof is omitted.

[0191] In operation 811, an MCG failure may occur between the UE and the network (or S-MN). In one embodiment, an MCG failure occurs when a radio link failure occurs in the MCG connection. More specifically, an MCG failure may occur in the following situations:

[0192] A UE configured with split SRB1 or SRB3 initiates the procedure to report MCG failures

[0193] - when neither MCG nor SCG transmission is suspended,

[0194] - when the SCG is not deactivated,

[0195] - when t316 is configured, and when the following condition is met:

[0196] 1> upon detecting radio link failure of the MCG, while T316 is not running),

[0197] When a UE has dual connection setup with a Pcell of an S-MN and a pscell of an S-SN, it can receive a CHO with candidate SCG setup from the network and perform measurement and condition evaluation operations for the related candidate target Pcell and Pscell.

[0198] According to one embodiment, the measurements corresponding to the candidate target Pcell and Pscell may be measurement objects indicated by each condition, and while performing the measurements, evaluations may be performed on specific events in the report configuration linked to the measurement object and condition information at the same time.

[0199] MCG failure may occur in certain MCG-related operations. If MCG Failure occurs, the UE may transmit MCG Failure Information to the network (or S-SN) in operation 813, according to the previously mentioned conditions. In one embodiment, the UE may include failure-related information in the MCG Failure Information message and transmit it to the network (or S-SN) using the SCG link.

[0200] In operation 815, the UE may not perform measurements on candidate target Pcells, and in operation 817, the UE may not perform measurements on candidate target PScells.

[0201] According to one embodiment, when the UE transmits an MCG Failure Information message through split SRB1 or SRB3, if CHO with candidate SCG is set, in operation 819, the UE may perform at least one of the following actions.

[0202] - In the CHO with candidate SCG setting, the evaluation operation of conditions corresponding to each candidate target pcell and pscell can be stopped.

[0203] - In the CHO with candidate SCG setting, the measurement operation being performed to evaluate the conditions corresponding to each candidate target pcell and pscell can be stopped.

[0204] ■ The corresponding measurement operation can be a measurement operation for the MO linked to the measurement ID indicated as condition information corresponding to each candidate target pcell and pscell of the CHO with candidate SCG setting.

[0205] The reason for stopping the above condition evaluation is that the UE has already notified the network of an MCG problem, so it must wait for additional commands or configuration from the network. If the UE were to move to a different Pcell on its own, the network would not only lose track of the UE's location but also be unable to configure the necessary commands in a timely manner. Therefore, the UE must be prevented from moving on its own.

[0206] In step 821, after the measurement operation and / or condition evaluation is stopped, the UE may receive an RRCReconfiguration message including new configuration information from the S-SN. According to an embodiment, the configuration information may include a configuration related to moving to a specific Pcell. According to an embodiment, the configuration information may include measurement configuration information in the corresponding Pcell. According to an embodiment, the configuration information may include a configuration of a new Cho with candidate SCG. The UE, upon receiving this new configuration information, may perform a measurement operation according to the configuration. This performance may or may not include re-instructing measurement on the existing Pcell.

[0207] The following abbreviations may be used in the present invention.

[0208] MN: master node

[0209] SN: secondary node

[0210] CPAC: Conditional PSCell addition and change, refers to the ability of a terminal to add or move to a related PSCell when certain conditions are met.

[0211] SCPAC: subsequent CPAC, subsequent CPAC refers to the ability to continuously perform CPAC operations without separate network configuration operations even after a terminal moves to a specific PSCell.

[0212] MO: measurement object

[0213] FIG. 9 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to one embodiment of the present disclosure.

[0214] More specifically, FIG. 9 is a diagram illustrating the information entered into each field and the operation of the terminal when a subsequent conditional PSCell addition and change (SCPAC) setting is created (is created) as a delta setting.

[0215] A terminal may receive an RRC reconfiguration message (or RRCReconfiguration message) from a base station. The RRCReconfiguration message may include a field (e.g., a conditional reconfiguration field) containing configuration information related to conditional mobility. More specifically, the RRCReconfiguration message may include a field that collects and transmits conditional mobility-related settings, for example, conditional reconfiguration.

[0216] The above conditional Reconfiguration field may include condition information that must be considered when moving from the current PSCell as a source cell to a candidate target PSCell, and target cell settings (or setting information) used when moving to the corresponding cell. The above information may be in the form of a list of entries linked to a condReconfig ID.

[0217] More specifically, the conditional Reconfiguration field may include an entry (hereinafter referred to as a “conditional candidate PSCell change configuration entry”) linked to at least one condReconfig ID. Each entry may include one condReconfig ID, at least one piece of condition information to be considered when moving from a current PSCell as a source cell to a candidate target PSCell, and configuration information of a target PSCell used when moving to a specific candidate target PSCell. Additionally, the conditional Reconfiguration field may also include an SCPAC reference config.

[0218] For example, as illustrated in FIG. 9, when the current PSCell is PSCell 5, the conditional Reconfiguration field may include a list of entries associated with the condReconfig ID, and each entry associated with the condReconfigID (or “conditional candidate PSCell change configuration entry”) may be as follows.

[0219] (1) The entry associated with condReconfig ID1 may include condReconfigID1, cond1, which is information to be considered when moving PSCell1 to target PSCell using PSCell5 as the source cell, and PSCell 1 config, which is configuration information of the target PSCell.

[0220] (2) The entry associated with condReconfig ID2 may include condReconfigID2, cond2, which is information to be considered when moving PSCell2 to target PSCell with PSCell5 as the source cell, and PSCell 2 config, which is configuration information of the target PSCell.

[0221] (3) The entry associated with condReconfig ID3 may include condReconfigID3, cond3, which is information to be considered when moving PSCell5 to the source cell and PSCell3 to the target PSCell, and PSCell 3 config, which is configuration information of the target PSCell.

[0222] (4) The entry associated with condReconfig ID4 may include condReconfigID4, cond4 which is information to be considered when moving PSCell5 to the source cell and PSCell4 to the target PSCell, and PSCell 4 config which is configuration information of the target PSCell.

[0223] For each of the above conditional candidate PSCell change configuration entries, an SCPAC configuration (or SCPAC config) may be added. When the SCPAC configuration (or SCPAC config) is indicated, the terminal may perform additional CPAC, i.e., subsequent CPAC operations, when moving (or changing) to the candidate target PSCell of the corresponding entry, and the SCPAC configuration (or SCPAC config) may include information necessary for such SCPAC operations.

[0224] The information required for the above SCPAC operation may include one or more of the following information.

[0225] - SCPAC config ID

[0226] ■ The above ID is an integer value

[0227] ■ One ID value is assigned to one source PSCell in response to a specific PSCell according to the source PSCell instruction information below.

[0228] - Source PSCell instruction information to apply the above SCPAC configuration

[0229] ■ PSCell instruction information can be one of the following:

[0230] ◆ In the Conditional Reconfiguration field that contained the above SCPAC settings, a specific condReconfig ID

[0231] ● In this case, the target pscell configuration information indicated by the condReconfig ID means the PSCell indicated by the PCI (physical cell identifier) ​​and AFRCN (absolute radio frequency channel number) in RRCReconfiguration as an octet string.

[0232] ◆ Combination of PCI and ARFCN information representing a specific PSCell

[0233] ◆ RRCReconfiguration message as a specific octet string

[0234] ● In this case, it means the PSCell that contains the reconfigurationWithSync field within the message and is indicated by the PCI and AFRCN within that field.

[0235] ■ If there is no explicit source PSCell information, the terminal considers the target PSCell in the entry of conditional Reconfiguration containing the SCPAC config as the source PSCell. This information can be used when storing in a long term variable.

[0236] - List of { conditional Reconfig ID, condition for the candidate target PSCell, the configuration of the candidate target PSCell}

[0237] ■ Conditional Reconfig ID: The ID in the entry of the above list is used to refer to each entry.

[0238] ■ The configuration of the candidate target PSCell: This is the target cell configuration information used when moving from the source PSCell associated with this SCPAC config to a specific target PSCell. It can be an RRCReconfiguration message of an octet string. The UE can recognize the target PSCell through the PCI and AFRCN present in the reconfigurationWithSync field in this message. This configuration information is the delta configuration used in combination with the SCPAC reference configuration. The combined configuration becomes the final configuration of the target PSCell.

[0239] ■ Condition for the candidate target PSCell: This is the condition information that must be satisfied when moving from the source PSCell associated with this SCPAC config to the candidate target PSCell. It can be indicated by the measId in the measurement config set by the current PSCell, i.e. the source PSCell associated with this SCPAC config, and if multiple measIds are indicated, the condition is considered satisfied only when all events corresponding to each measId are satisfied.

[0240] For example, as illustrated in FIG. 9, the entry associated with condReconfig ID3 and the entry associated with condReconfig ID4 may each additionally include SCPAC config.

[0241] (1) An entry associated with condReconfig ID3 may include SCPAC config1, and the SCPAC config1 may include one or more of the following information.

[0242] 1) SCPAC id value: 1 here

[0243] 2) Source PSCell instruction information to apply the above SCPAC config1

[0244] - For example, it may include an RRCReconfiguration message that includes CondRecondig ID3, a combination of PCI and ARFCN information indicating PSCell3, or a reconfigurationWithSync field indicating PSCell3.

[0245] - However, it may not contain source PSCell instruction information.

[0246] 3) A list of information to move from the source PSCell (i.e., PSCell3) linked to the above SCPAC config1 to a specific target PSCell.

[0247] - ConditionalReconfig ID1, Target PSCell 1 config (PSCell1 configuration information used when moving from PSCell3 to PSCell1), condition information that must be satisfied when moving from PSCell3 to PSCell1

[0248] - ConditionalReconfig ID2, Target PSCell 4 config (PSCell4 configuration information used when moving from PSCell3 to PSCell4), condition information that must be satisfied when moving from PSCell3 to PSCell4

[0249] (2) The entry associated with condReconfig ID4 may include SCPAC config2, and the SCPAC config2 may include one or more of the following information.

[0250] 1) SCPAC id value: 2 here

[0251] 2) Source PSCell instruction information to apply the above SCPAC config2

[0252] - For example, it may include an RRCReconfiguration message that includes CondRecondig ID4, or a combination of PCI and ARFCN information indicating PSCell4, or a reconfigurationWithSync field indicating PSCell4.)

[0253] - However, it may not contain source PSCell instruction information.

[0254] 3) A list of information to move from the source PSCell (i.e., PSCell4) linked to the above SCPAC config2 to a specific target PSCell.

[0255] - ConditionalReconfig ID1, Target PSCell 1 config (PSCell1 configuration information used when moving from PSCell4 to PSCell1), condition information that must be satisfied when moving from PSCell4 to PSCell1

[0256] - ConditionalReconfig ID2, Target PSCell 3 config (PSCell3 configuration information used when moving from PSCell4 to PSCell3), condition information that must be satisfied when moving from PSCell4 to PSCell3

[0257] In the present figure 9, it is assumed that the candidate target PSCell used in SCPAC operation is given as a delta setting.

[0258] For this purpose, the network can separately transmit the reference configuration for SCPAC (or SCPAC reference config) to the conditional Reconfiguration field. Based on the SCPAC reference configuration, the terminal can configure the final target PSCell configuration by adding the configuration of each candidate target PSCell existing in the SCPAC config in a delta manner, and perform SCPAC by applying the final target PSCell configuration during SCPAC operation.

[0259] When the terminal receives an RRCReconfiguration message including the above information, it can perform operations on the short term variable and the long term variable.

[0260] - short-term variable

[0261] For short term variables, the terminal can store the condReconfig Id, candidate target PSCell conditions, and target set settings (or configuration information) for all entries in the conditional Reconfiguration in VarConditionalReconfiguration or short term variables. Based on the condition information of this stored entry, the terminal can perform a measurement operation based on the MO (measurement object) related to the measId that indicates the condition information, and simultaneously start evaluating the event in the reportconfig related to the measId.

[0262] - long term variable

[0263] In the case of long term variables, if the terminal contains an SCPAC config field among the entries in the conditional reconfiguration, the corresponding SCPAC configs can be stored in the long term variable. At this time, the SCPAC id, source PSCell information, and list of {condReconfig ID, condition, target cell configuration of the candidate target pscell} can be stored. In addition, in the case of the delta configuration method, the SCPAC reference configuration can be stored.

[0264] For example, as illustrated in FIG. 9, the terminal can store the following information in a short term variable and a long term variable.

[0265] - short-term variable

[0266] (1) Entry associated with condReconfig ID1 - condReconfigID1, cond1, and PSCell 1 config

[0267] (2) Entry associated with condReconfig ID2 - condReconfigID2, cond2, and PSCell 2 config

[0268] (3) Entry associated with condReconfig ID3 - condReconfigID3, cond3, and PSCell 3 config

[0269] (4) Entry associated with condReconfig ID4 - condReconfigID4, cond4, and PSCell 4 config

[0270] - long term variable

[0271] (1) SCPAC config1 - SCPAC id1, (source PSCell instruction information to apply the above SCPAC config1), {ConditionalReconfig ID1, Target PSCell 1 config, condition}, {ConditionalReconfig ID2, Target PSCell 4 config, condition}

[0272] (2) SCPAC config2 - SCPAC id2, (source PSCell instruction information to apply the above SCPAC config2), {ConditionalReconfig ID1, Target PSCell 1 config, condition}, {ConditionalReconfig ID2, Target PSCell 3 config, condition}

[0273] (3) If necessary, SCPAC reference config

[0274] After this, if the terminal performs CPC with a specific PSCell existing in the short term variable or successfully performs a general PSCell change, the terminal can release all entries in the short term variable. Here, a successful PSCell change may mean transmitting the RRCRecongiruationComplete message.

[0275] After the above PSCell change is successfully performed, the terminal can store some information of the long term variable in the released short term variable.

[0276] Here, some of the information stored in the short term variable refers to the internal information of the SCPAC config that the current PSCell to which the UE has moved by performing a PSCell change is indicated as the source PSCell or is linked to. That is, the list of {condReconfig ID, candidate target pscell configuration, condition for CPAC execution to this candidate target pscell} of the SCPAC config that indicates the cell that has completed moving to a new PSCell as the source PSCell can be.

[0277] For example, as illustrated in FIG. 9, the terminal can store the following information, which is part of the long term variable, in the short term variable.

[0278] If the terminal performs a PSCell change to PSCell3, since the current PSCell, PSCell3, is the source PSCell, {ConditionalReconfig ID1, Target PSCell 1 config, condition} and {ConditionalReconfig ID2, Target PSCell 4 config, condition} associated with PSCell3 can be stored in a short term variable.

[0279] After updating the above short term variable, the terminal can perform measurement and condition evaluation operations based on condition information for each id included in the above short term variable.

[0280] FIG. 10 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0281] More specifically, FIG. 10 is a case where the id value for the delta configuration is replaced in the subsequent conditional PSCell addition and change (SCPAC) setting.

[0282] The embodiment of FIG. 10 is a method for solving a problem in which, when setting information corresponding to delta for each target PPSCell is stored in the SCPAC config as described above in FIG. 9 and transmitted to a terminal, the final target PSCell configuration is the same for the same PSCell, but is repeatedly stored and transmitted during signal transmission.

[0283] In Fig. 9, the target PSCell 1 config of SCPAC config 1 is the same as the target PSCell 1 config of SCPAC config 2. That is, when using the SCPAC reference configuration, the delta target PSCell configuration is the same regardless of the source PSCell, and accordingly, the final target PSCell configuration (=reference config + delta config) is also the same for each target PSCell.

[0284] In this case, to reduce the amount of signal, the ID of the target PSCell can be indicated instead of the delta configuration of the target PSCell for each SCPAC config. In addition, the conditional Reconfiguration field can separately include the SCPAC reference configuration. The terminal can derive the final PSCell configuration of a specific target PSCell by adding the delta configuration indicated by the ID of the specific target PSCell to the SCPAC reference configuration.

[0285] When the terminal receives the above configuration information and stores the information required by the terminal in a long term variable, there is a method of separately storing the SCPAC reference configuration and delta configuration as received, and storing the ID of the corresponding PSCell for each target PSCell in each SCPAC config.

[0286] Alternatively, unlike when received, the SCPAC reference config and the delta configuration for each target PSCell can be combined to store the final target PSCell for each SCPAC config (e.g. in the form of RRCReconfiguration as an octet string).

[0287] For example, as illustrated in FIG. 10, when the current PSCell is PSCell 5, the conditional Reconfiguration field may include a list of entries linked to the condReconfig ID and the SCPAC reference config.

[0288] (1) condReconfig ID1 related entries - condReconfigID1, cond1, and PSCell 1 config

[0289] (2) condReconfig ID2 related entries - condReconfigID2, cond2, and PSCell 2 config

[0290] (3) condReconfig ID3 related entries - condReconfigID3, cond3, PSCell 3 config, and SCPAC config1

[0291] 3-1) SCPAC config1 can contain the following information:

[0292] - SCPAC id1, (source PSCell instruction information to apply the above SCPAC config1), {ConditionalReconfig ID1, Target PSCell 1 id1, condition}, {ConditionalReconfig ID2, Target PSCell 1 id4, condition}

[0293] (4) condReconfig ID4 related entries - condReconfigID4, cond4, PSCell 4 config, and SCPAC config2

[0294] 4-1) SCPAC config2 can contain the following information:

[0295] - SCPAC id2, (source PSCell instruction information to apply the above SCPAC config2), {ConditionalReconfig ID1, Target PSCell 1 id1, condition}, {ConditionalReconfig ID2, Target PSCell 1 id3, condition}

[0296] (5) SCPAC reference config, List of {Target PSCell id, delta config per target PSCell}

[0297] According to the embodiment of FIG. 10, the terminal can store the changed content compared to FIG. 9 in a long term variable. In particular, the ID of the target PSCell can be stored at the time of storage.

[0298] In another embodiment of the present disclosure, the final target PSCell configuration may be stored by combining the SCPAC reference configuration and the delta configuration. If the final target PSCell configuration is combined, there is no need to store the SCPAC reference configuration and the list of {target PSCell id, delta config per target PSCell} separately in the long term variable.

[0299] For example, as shown in Fig. 10, the following information can be stored in a long term variable.

[0300] (1) SCPAC config1 - SCPAC id1, (source PSCell instruction information to apply the above SCPAC config1), {ConditionalReconfig ID1, Target PSCell id 1 (or final Target PSCell config), condition}, {ConditionalReconfig ID2, Target PSCell id 4 (or final Target PSCell config), condition}

[0301] (2) SCPAC config2 - SCPAC id2, (source PSCell instruction information to apply the above SCPAC config2), {ConditionalReconfig ID1, Target PSCell id 1 (or final Target PSCell config), condition}, {ConditionalReconfig ID2, Target PSCell id 3 (or final Target PSCell config), condition}

[0302] (3) When storing the id of the target PSCell, SCPAC reference config and List of {Target PSCell id, delta config per target PSCell}

[0303] The operation for short term variables is the same as in Fig. 9. That is, the id, condition, and target PSCell settings can be stored in all entries of the conditional reconfiguration settings, and measurement and condition evaluation operations can be performed according to the corresponding condition information.

[0304] If a PSCell change occurs, the terminal can release all entries of the short term variable and store only the contents of the SCPAC config with the PSCell in which the PSCell change was successful as the source cell in the long term variable to the short term variable.

[0305] At this time, the content of storing some of the SCPAC config in the long term variable to the short term variable may have different operations depending on the format in which it is stored in the previously mentioned long term variable.

[0306] If the SCPAC reference configuration and delta configuration are stored in the long term variable, and the target PSCell ID is stored in the entries of each SCPAC config, the terminal can derive the final PSCell configuration by combining the reference configuration and delta configuration stored in the long term variable as the target PSCell setting corresponding to each condReconfig ID, and store it in the short term variable.

[0307] If the final target PSCell configuration is stored in the long term variable instead of the target pscell id within each SCPAC config, the terminal can store the target PSCell configuration stored in the short term variable for each condReconfig Id as the final target PSCell configuration, not the target PSCell id. In this case, the final target PSCell configuration is not a delta configuration corresponding to the reference, but a full configuration, and in all candidate target PSCell configurations mentioned in this specification, in the part where the final configuration or full configuration is considered, a 1-bit indicator may be additionally added to indicate whether the corresponding configuration is a full configuration or not. This content can be added to each corresponding entry, and is possible in both short term and long term variables.

[0308] For example, as illustrated in FIG. 10, the terminal can store the following information, which is part of the long term variable, back into the short term variable.

[0309] If the terminal performs a PSCell change to PSCell3, since the current PSCell, PSCell3, is the source PSCell, {ConditionalReconfig ID1, Target PSCell 1 config, condition} and {ConditionalReconfig ID2, Target PSCell 4 config, condition} associated with PSCell3 can be stored in a short term variable.

[0310] FIG. 11 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0311] More specifically, FIG. 11 is a diagram illustrating a case in which target PSCell settings are transmitted to a terminal from the beginning as a full configuration without a reference configuration.

[0312] In Fig. 10, instead of the example of information consisting of a reference configuration and a delta configuration per candidate target PSCell, the full configuration for each candidate target PSCell can be transmitted to the terminal through the conditional reconfiguration field. To this end, a separate ID can be assigned to the full configuration of each candidate target PSCell. In addition, this ID can be referred to as the configuration information of the target PSCell within each SCPAC config.

[0313] For example, as illustrated in FIG. 11, when the current PSCell is PSCell 5, the conditional Reconfiguration field may include a list of entries linked to the condReconfig ID and the SCPAC full config.

[0314] (1) condReconfig ID1 related entries - condReconfigID1, cond1, and PSCell 1 config, {SCPAC availability}

[0315] (2) condReconfig ID2 related entries - condReconfigID2, cond2, and PSCell 2 config, {SCPAC availability}

[0316] (3) condReconfig ID3 related entries - condReconfigID3, cond3, PSCell 3 config, and SCPAC config1

[0317] 3-1) SCPAC config1 can contain the following information:

[0318] - SCPAC id1, (source PSCell instruction information to apply the above SCPAC config1), {ConditionalReconfig ID1, fullconfig ID 1, condition}, {ConditionalReconfig ID2, fullconfig ID 4, condition}

[0319] (4) condReconfig ID4 related entries - condReconfigID4, cond4, PSCell 4 config, and SCPAC config2

[0320] 4-1) SCPAC config2 can contain the following information:

[0321] - SCPAC id2, (source PSCell instruction information to apply the above SCPAC config2), {ConditionalReconfig ID1, fullconfig ID 1, condition}, {ConditionalReconfig ID2, fullconfig ID 3, condition}

[0322] (5) SCPAC full config: list of {id, candidate PSCell config (octet string)}

[0323] According to another embodiment of the present disclosure, as target PSCell configuration information within each SCPAC config, source cell configuration information of the SCPAC config may also be referred to.

[0324] For example, if the source cell information of SCPAC config is an octet string of the full configuration of the PSCell used when migrating to the corresponding PSCell, then the settings to be used when migrating to each target PSCell used in SCPAC operation can refer to the id of the SCPAC config that has each PSCell as the source PSCell. For example, if the source cell of a specific SCPAC config is PSCell 3 and the settings applied by the terminal when migrating to the corresponding PSCell 3 (e.g., RRCReconfiguration of octet string), then in other SCPAC configs, when considering PSCell 3 as a candidate target PSCell, the id of the SCPAC config that has the settings used when migrating to the corresponding PSCell 3 as the source information can be referred to.

[0325] More specifically, referring to FIG. 11, SCPAC config1 and SCPAC config2 may include SCPAC id instead of fullconfig ID.

[0326] 3-1) SCPAC config1 may include the ID of the SCPAC config that has the target PSCell as the source PSCell instead of the aforementioned fullconfig ID1. That is, it may include the ID of the SCPAC config that has PSCell 1 as the source PSCell.

[0327] 3-2) Similarly, SCPAC config1 may contain the ID of the SCPAC config that has the target PSCell as the source PSCell instead of the aforementioned fullconfig ID4. That is, it may contain the ID of the SCPAC config that has PSCell 4 as the source PSCell.

[0328] 4-1) SCPAC config2 may contain the ID of the SCPAC config that has the target PSCell as the source PSCell instead of the aforementioned fullconfig ID1. That is, it may contain the ID of the SCPAC config that has PSCell 4 as the source PSCell.

[0329] 4-2) Similarly, SCPAC config2 may contain the ID of the SCPAC config that has the target PSCell as the source PSCell instead of the aforementioned fullconfig ID4. That is, it may contain the ID of the SCPAC config that has PSCell 4 as the source PSCell.

[0330] The operations of the long term variable and short term variable below are the same as in the above-described Figures 9 and 10.

[0331] FIG. 12 is a diagram illustrating a subsequent conditional PSCell addition and change (SCPAC) setting method according to another embodiment of the present disclosure.

[0332] More specifically, Fig. 12 proposes a method for increasing the degree of freedom of SCPAC config settings.

[0333] In the embodiments described above, the SCPAC config is proposed as a configuration that is available after migrating to a specific target PSCell within the conditional reconfiguration field. According to the embodiments described above, there is no way for the network to convey the required SCPAC config before migrating to the target PSCell.

[0334] For example, if the current terminal is located in PSCell 5, the information that can be given as SCPAC configuration can only indicate SCPAC configuration thereafter when moving to PSCell 3 or PSCell 4. If the information required when moving from PSCell 5 to other pscells is not signaled with the current structure.

[0335] To solve this problem, even if there is no SCPAC config field in a specific entry within conditional Reconfiguration, if a separate indication is added, the conditions that must be satisfied when moving to the target PSCell of the entry and the target PSCell configuration information can be used as information in the SCPAC config.

[0336] For example, in the case of condReconfig ID 1 and 2 in Fig. 12, if a separate availability indicator exists, the condition information for moving to the corresponding target PSCell and the target PSCell configuration information are considered as entries of the SCPAC config, so that the terminal can store the corresponding SCPAC config in a long term variable. At this time, the SCPAC id can be a predefined id assigned internally to the terminal.

[0337] More specifically, as illustrated in FIG. 12, when the current PSCell is PSCell 5, the conditional Reconfiguration field may include a list of entries linked to the condReconfig ID and the SCPAC reference config.

[0338] (1) condReconfig ID1 related entries - condReconfigID1, cond1, PSCell 1 config, and SCPAC availablity

[0339] (2) condReconfig ID2 related entries - condReconfigID2, cond2, PSCell 2 config, and SCPAC availablity

[0340] (3) condReconfig ID3 related entries - condReconfigID3, cond3, PSCell 3 config, and SCPAC config1

[0341] (4) condReconfig ID4 related entries - condReconfigID4, cond4, PSCell 4 config, and SCPAC config2

[0342] (5) SCPAC reference config

[0343] Afterwards, as illustrated in Fig. 12, for condReconfig ID 1 and 2, since separate SCPAC availablity exists, the following new entries can be additionally stored in the long term variable of the terminal. It is assumed that the predefined SCPAC id is SCPAC id0.

[0344] - SCPAC id0, (information indicating the source cell, i.e., the current PSCell, PScell5), {ConditionalReconfig ID1, Target PSCell 1 config, condition1}, {ConditionalReconfig ID2, Target PSCell 2 config, condition 2}

[0345] The operation for short term variables is the same as in Fig. 7. That is, the id, condition, and target PSCell settings can be stored in all entries of the conditional reconfiguration settings, and measurement and condition evaluation operations can be performed according to the corresponding condition information.

[0346] According to another embodiment of the present disclosure, since the information included in the conditional Reconfiguration field based on the current PSCell 5 is information about movement to another PSCell, it is not possible to transmit configuration information about SCPAC movement from the current own PSCell, i.e., PSCell 5, to another candidate PSCell.

[0347] To address this issue, the network can leave the condition field or target PSCell configuration field empty for a specific entry within the conditional reconfiguration field and add an SCPAC config field to that entry. In this case, the terminal can recognize the SCPAC config as a configuration for SCPAC migration from the current PSCell to another PSCell.

[0348] Based on this, the terminal can store the corresponding SCPAC configs in a long term variable.

[0349] According to another embodiment of the present disclosure, an SCPACToAddMod field and an SCPACToRelease field may be introduced.

[0350] More specifically, in the cases of the above-described drawings 9 to 12, all are sub-fields of SCPAC config, and also as upper fields including contents proposed to be included in SCPAC config, the SCPACToAddMod field and the SCPACToRelease field can be introduced.

[0351] SCPACToAddMod can include the contents suggested above, and if an entry in an SCPAC config needs to be added / modified, it can transmit the added / modified information to the terminal.

[0352] For example, if information of SCPAC id 1 is already stored in a long variable, and the information is {condReconfig Id 1, target PSCell 1 config, condition 1}, {condReconfig Id 2, target PSCell 2 config, condition 2}, then SCPAC id 1 is recorded in the newly received SCPACToAddMod field, and if {condReconfig Id 3, target PSCell 3, condition 3} is included, the terminal can add the entry information of the new condReconfig Id 3 to the entry of SCPAC id 1.

[0353] If information including the condReconfig Id previously stored in the SCPACToAddMod field is transmitted, the terminal can change the entry information of the condReconfig ID to a new entry.

[0354] If the terminal receives the SCPAC id in the SCPACToRelease field, the terminal can release the entire SCPAC config corresponding to the SCPAC id that currently exists in the long term variable. In addition, if the SCPACToRElease field includes the SCPAC id and additionally includes a specific condReconfig Id, the terminal can delete the entry corresponding to the specific condREconfig Id among the entries of the SCPAC id.

[0355] When the terminal performs an operation to update or delete information of a long term variable, if the current PSCell adds, modifies, or releases an SCPAC config entry indicated as the source PSCell, the terminal must also add, modify, or release the corresponding entries in the current short term variable.

[0356] Long term variable can release all entries when receiving RRC Release and performing RRC reestablishment operation.

[0357] On the other hand, a relatively short term variable can release all entries when receiving an RRC Release, in an RRC reestablishment situation, or when performing a PSCell change.

[0358] FIG. 13 is a flowchart illustrating a flow for performing a subsequent conditional PSCell addition and change (SCPAC) operation of a terminal according to an embodiment of the present disclosure.

[0359] More specifically, FIG. 13 is a diagram for a case where a terminal receives subsequent PSCell addition and change (SCPAC) settings and performs SCPAC operations.

[0360] At step 1310, the user equipment (UE, 1301) has established a dual connection with the S-MN (source - master node, 1303) and the S-SN (source - secondary node, 1305). (Dual connection configured)

[0361] At step 1315, the MN or SN may initiate CPAC (conditional PSCell change and addition) setup and SCPAC (subsequent CPAC) setup configuration preparation process. (SCPAC preparation among MN and SNs)

[0362] At step 1320, the terminal (1301) can receive an RRC Reconfiguration message including conditional Reconfiguration with SCPAC configuration information from the S-MN (1305). (RRCReconfiguration including conditional Reconfiguration with SCPAC configs)

[0363] More specifically, the S-MN (1305) can transmit CPAC configuration and SCPAC configuration information to the terminal (1301) through the conditional Reconfiguration field of the RRCReconfiguration message.

[0364] At step 1325, the terminal (1301) that has received the information can store the information in a short term variable and a long term variable using one of the methods proposed in FIGS. 7 to 10 described above. The terminal (1301) can perform measurement and condition determination operations of the source PSCell and the candidate target PSCell based on the condition information among the information stored in the short term variable.

[0365] After this, at step 1330, the terminal (1301) can perform a PSCell change to the corresponding PSCell if the condition for the candidate PSCell of a specific CPAC is satisfied (or is satisfied).

[0366] At this time, the terminal (1301) can release all entries of the existing short term variable and, in the long term variable, add information in the SCPAC config indicating the PSCell that has completed the change and is currently being connected as the source PSCell to the short term variable.

[0367] Step 1335: The terminal (1301) and the new target-secondary node 1 (T-SN1) (1307) can perform a random access procedure.

[0368] Step 1340 The terminal (1301) can transmit the RRCReconfigurationComplete message to the T-SN1 (1307).

[0369] Although steps 1335 and 1340 are illustrated as being performed after step 1330, the scope of the present invention is not limited thereto. Steps 1335 and 1340 may be included in the procedure for performing PSCell change in step 1330, and the terminal (1301) may release all entries of the short term variable and add some information of the long term variable after transmitting the RRCReconfigurationComplete message to the T-SN1 (1307).

[0370] At step 1345, the terminal (1301) can continue measurement and evaluation operations for SCPAC corresponding conditions based on the information in the added short term variable.

[0371] The methods according to the embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

[0372] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present invention.

[0373] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0374] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present invention via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present invention.

[0375] In the specific embodiments of the present invention described above, components included in the invention are expressed in the singular or plural form depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present invention is not limited to singular or plural components. Even components expressed in the plural form may be composed of singular elements, or even components expressed in the singular form may be composed of plural elements.

[0376] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims but also by equivalents thereof.

Claims

1. In a method of UE (user equipment) in a wireless communication system, An operation of receiving an RRC (radio resource control) reconfiguration message from a base station that includes configuration information for a CHO (conditional handover) through a candidate SCG (secondary cell group); When an SCG connection failure (SCG failure) of the above UE occurs, an operation of transmitting SCG failure information to the base station; and A method characterized by including an action of stopping measurement for a candidate PSCell (primary secondary cell) when transmitting the above SCG failure information.

2. In the first paragraph, the SCG connection failure (SCG failure) is A method characterized in that at least one of a radio link failure (RLF) in an SCG connection, an SCG reconfiguration failure, a beam failure of PSCell while SCG is deactivated, and an SCG integrity check failure occurs.

3. In the first paragraph, the setting information for CHO through the candidate SCG is, A method characterized by including at least one of a list of candidate PCell (primary cell) settings and candidate PSCell settings, a list of target PCell conditions and target PSCell conditions, and a conditional reconfiguration ID.

4. In paragraph 1, A method further characterized by including an operation of stopping condition evaluation for candidate PCell and candidate PSCell determined based on configuration information for CHO through the above candidate SCG.

5. In a method of UE (user equipment) in a wireless communication system, An operation of receiving an RRC (radio resource control) reconfiguration message from a base station that includes configuration information for a CHO (conditional handover) through a candidate SCG (secondary cell group); When a master cell group (MCG) connection failure (MCG failure) of the above UE occurs, an operation of transmitting MCG failure information to the base station; and A method characterized by comprising an action for stopping condition evaluation for CHO via SCG.

6. In paragraph 5, A method characterized in that the above MCG failure information is transmitted through split SRB1 (signaling radio bearer 1) or SRB3.

7. In paragraph 5, the setting information for CHO through the candidate SCG is, A method characterized by including at least one of a list of candidate PCell (primary cell) settings and candidate PSCell settings, a list of target PCell conditions and target PSCell conditions, and a conditional reconfiguration ID.

8. In paragraph 1, A method further characterized by including an operation of stopping measurements for candidate PCell and candidate PSCell determined based on the configuration information for CHO through the candidate SCG.

9. In a wireless communication system, in the UE (user equipment), Transmitter and receiver; and comprising a control unit, said control unit comprising: Receive an RRC (radio resource control) reconfiguration message from a base station that includes configuration information for a CHO (conditional handover) through a candidate SCG (secondary cell group), When an SCG connection failure (SCG failure) of the above UE occurs, control is made to transmit SCG failure information to the base station, A UE characterized in that measurement for a candidate PSCell (primary secondary cell) is stopped when the above SCG failure information is transmitted.

10. In the 9th paragraph, the SCG connection failure (SCG failure) is A UE characterized in that at least one of a radio link failure (RLF) in an SCG connection, an SCG reconfiguration failure, a beam failure of PSCell while SCG is deactivated, and an SCG integrity check failure has occurred.

11. In paragraph 9, the setting information for CHO through the candidate SCG is, A UE characterized by including at least one of a list of candidate PCell (primary cell) settings and candidate PSCell settings, a list of target PCell conditions and target PSCell conditions, and a conditional reconfiguration ID.

12. In paragraph 9, the control unit, A UE characterized by stopping condition evaluation for candidate PCell and candidate PSCell based on configuration information for CHO through the above candidate SCG.

13. In a wireless communication system, in the UE (user equipment), Transmitter and receiver; and comprising a control unit, said control unit comprising: Receive an RRC (radio resource control) reconfiguration message from a base station that includes configuration information for a CHO (conditional handover) through a candidate SCG (secondary cell group), When an MCG (master cell group) connection failure (MCG failure) of the above UE occurs, control is provided to transmit MCG failure information to the base station. A UE characterized by stopping condition evaluation for CHO via SCG.

14. In paragraph 13, A UE characterized in that the above MCG failure information is transmitted via split SRB1 (signaling radio bearer 1) or SRB3.

15. In the 13th paragraph, the setting information for CHO through the candidate SCG is, A UE characterized by including at least one of a list of candidate PCell (primary cell) settings and candidate PSCell settings, a list of target PCell conditions and target PSCell conditions, and a conditional reconfiguration ID.

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