Method and apparatus for continuous 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. More particularly, the present disclosure proposes a method and an apparatus for continuous conditional handover (or continuous conditional PSCell change and addition, or subsequent PSCell change and addition (SCPAC)).

Description

Method and device for performing continuous conditional handover in next-generation mobile communication system

[0001] The present invention relates to the operation of a base station and a terminal in a mobile communication system. More specifically, the present invention relates to a method and device for performing continuous conditional handover of a terminal.

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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.

[0006] 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).

[0007] 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.

[0008] 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.

[0009] The present disclosure proposes a method and apparatus for performing continuous conditional handover (or continuous conditional PSCell change and addition, subsequent PSCell change and addition, SCPAC) to solve the above-described problems.

[0010] The present disclosure relates to a method and device for displaying information about a target cell to which movement is impossible and updating terminal variables of a terminal when movement to a target cell is impossible during a network continuous conditional handover (or SCPAC) operation.

[0011] 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.

[0012] In order to solve the above problems, the present invention provides a method performed by a terminal of a wireless communication system, the method comprising the steps of: obtaining, from a base station, SCPAC configuration information including information on at least one subsequent PSCell addition and change (SCPAC) candidate cell; wherein the SCPAC configuration information relates to configuration of a cell not allowed to move among the at least one SCPAC candidate cell; determining, based on the configuration information on the SCPAC, a cell not to perform condition evaluation among the at least one SCPAC candidate cell; performing condition evaluation on cells excluding a cell not to perform condition evaluation among the at least one SCPAC candidate cell; and performing an SCPAC operation based on the condition evaluation.

[0013] The present invention for solving the above problems is a method performed by a base station of a wireless communication system, comprising the steps of: generating SCPAC configuration information including information on at least one subsequent PSCell addition and change (SCPAC) candidate cell; and transmitting SCPAC configuration information including information on the at least one SCPAC candidate cell to a terminal, wherein the SCPAC configuration information is characterized in that it relates to configuration of a cell in which movement is not permitted among the at least one SCPAC candidate cell.

[0014] In order to solve the above problems, the present invention provides a terminal of a wireless communication system, comprising: a transceiver for transmitting and receiving signals; and a control unit coupled with the transceiver, wherein the control unit obtains, from a base station, SCPAC configuration information including information on at least one subsequent PSCell addition and change (SCPAC) candidate cell, wherein the SCPAC configuration information relates to configuration of a cell from which movement is not permitted among the at least one SCPAC candidate cell; and, based on the configuration information on the SCPAC, determines a cell from among the at least one SCPAC candidate cell that does not perform condition evaluation, performs condition evaluation on cells excluding a cell from among the at least one SCPAC candidate cell for which it is determined not to perform condition evaluation, and performs an SCPAC operation based on the condition evaluation.

[0015] In order to solve the above problems, the present invention provides a base station of a wireless communication system, comprising: a transceiver for transmitting and receiving a signal; and a control unit coupled with the transceiver, wherein the control unit generates SCPAC configuration information including information on at least one subsequent PSCell addition and change (SCPAC) candidate cell, and transmits the SCPAC configuration information including information on the at least one SCPAC candidate cell to a terminal, wherein the SCPAC configuration information is characterized in that it relates to configuration of a cell in which movement is not permitted among the at least one SCPAC candidate cell.

[0016] According to one embodiment of the present disclosure, the terminal does not experience any problem in condition measurement during continuous conditional handover (or subsequent conditional PSCell change and addition, SCPAC) operations.

[0017] 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.

[0018] FIG. 1 is a diagram illustrating the structure of a long term evolution (LTE) system according to one embodiment of the present disclosure.

[0019] FIG. 2 is a diagram illustrating a wireless protocol structure of a long term evolution (LTE) system according to an embodiment of the present disclosure.

[0020] FIG. 3 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0021] 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.

[0022] FIG. 5 is a block diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0023] FIG. 6 is a block diagram illustrating the structure of a new radio (NR) base station according to one embodiment of the present disclosure.

[0024] FIG. 7A is a diagram illustrating mobility between target cells in a subsequent conditional PSCell addition and change (SCPAC) according to one embodiment of the present disclosure.

[0025] FIG. 7b is a diagram illustrating a method for setting and updating subsequent conditional PSCell addition and change (SCPAC).

[0026] FIG. 8 is a diagram illustrating a method for setting up subsequent conditional PSCell addition and change (SCPAC) according to one embodiment of the present disclosure.

[0027] FIG. 9 is a diagram illustrating a method for a network to set up subsequent conditional PSCell addition and change (subsequent CPAC, SCPAC) to a terminal according to an embodiment of the present disclosure.

[0028] FIG. 10 is a diagram illustrating a method for performing sequential conditional PSCell addition and change (subsequent CPAC, SCPAC) to a terminal according to one embodiment of the present disclosure.

[0029]

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] 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.

[0035] 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).

[0036] FIG. 1 is a diagram illustrating the structure of a long term evolution (LTE) system according to one embodiment of the present disclosure.

[0037] Referring to FIG. 1, a wireless access network of a long term evolution (LTE) system as illustrated in FIG. 1 may be composed of next generation base stations (Evolved Node Bs, hereinafter ENBs, Node Bs or base stations) (1-05, 1-10, 1-15, 1-20), a mobility management entity (MME) (1-25) and an S-GW (1-30, Serving-Gateway). A user equipment (UE or terminal) (1-35) may access an external network through the ENBs (1-05 to 1-20) and the S-GW (1-30).

[0038] In Fig. 1, ENBs (1-05 to 1-20) may correspond to existing Node Bs of a UMTS system. ENBs are connected to UEs (1-35) 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 the buffer status, available transmission power status, and channel status of UEs and performs scheduling is required, and ENBs (1-05 to 1-20) may be responsible for this. One ENB can typically control multiple cells. For example, in order to achieve 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. Additionally, an adaptive modulation and coding (AMC) method can be applied, which determines the modulation scheme and channel coding rate according to the channel status of the terminal.

[0039] S-GW (serving-gateway, 1-30) is a device that provides data bearers and can create or remove data bearers under the control of MME (1-25).

[0040] MME (mobility management entity, 1-25) is a device that is responsible for mobility management functions for terminals as well as various control functions, and can be connected to multiple base stations.

[0041] FIG. 2 is a diagram illustrating a wireless protocol structure of a long term evolution (LTE) system according to an embodiment of the present disclosure.

[0042] Referring to FIG. 2, the wireless protocol of the long term evolution (LTE) system may be composed of Packet Data Convergence Protocol (PDCP) (2-05, 2-40), Radio Link Control (RLC) (2-10, 2-35), and Medium Access Control (MAC) (2-15, 2-30) in the terminal and ENB, respectively.

[0043] Packet Data Convergence Protocol (PDCP) (2-05, 2-40) can handle operations such as IP header compression / decompression. The main functions of PDCP can be summarized as follows.

[0044] - Header compression and decompression (ROHC only)

[0045] - User data transfer function

[0046] - In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

[0047] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0048] - Duplicate detection function (Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

[0049] - 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)

[0050] - Encryption and decryption functions (Ciphering and deciphering)

[0051] - Timer-based SDU discard in uplink.

[0052] Radio Link Control (RLC) (2-10, 2-35) can perform ARQ operations, etc. by reconfiguring PDCP packet data units (PDUs) to an appropriate size. The main functions of RLC can be summarized as follows.

[0053] - Data transfer function (Transfer of upper layer PDUs)

[0054] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0055] - Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

[0056] - Re-segmentation of RLC data PDUs (only for AM data transfer)

[0057] - Reordering of RLC data PDUs (only for UM and AM data transfer)

[0058] - Duplicate detection (only for UM and AM data transfer)

[0059] - Error detection function (Protocol error detection (only for AM data transfer))

[0060] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

[0061] - RLC re-establishment function

[0062] Medium Access Control (MAC) (2-15, 2-30) connects 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 can be summarized as follows.

[0063] - Mapping function (Mapping between logical channels and transport channels)

[0064] - 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)

[0065] - Scheduling information reporting function

[0066] - HARQ function (Error correction through HARQ)

[0067] - Priority handling between logical channels of one UE

[0068] - Priority handling between UEs by means of dynamic scheduling

[0069] - MBMS service identification function

[0070] - Transport format selection function

[0071] - Padding function

[0072] The physical layer (phy) (2-20, 2-25) can perform the 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.

[0073] FIG. 3 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0074] Referring to FIG. 3, a wireless access network of a next-generation mobile communication system (hereinafter referred to as new radio (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) (3-10) and a next-generation radio core network (New Radio Core Network, NR CN) (3-05). A next-generation radio user equipment (NR UE or terminal) (3-15) may access an external network through the NR gNB (3-10) and the NR CN (3-05).

[0075] In Fig. 3, the NR gNB (3-10) may correspond to an eNB (Evolved Node B) of an existing LTE system. The NR gNB is connected to an NR UE (3-15) via a wireless channel and may provide superior services than an existing Node B.

[0076] In next-generation mobile communication systems, all user traffic can be serviced through a shared channel. Therefore, a device is needed to collect status information, such as UE buffer status, available transmit power status, and channel status, and perform scheduling. This scheduling can be performed by an NR NB (3-10). A single NR gNB can control multiple cells.

[0077] In next-generation mobile communication systems, bandwidths exceeding the typical maximum bandwidth may be applied to achieve ultra-high-speed data transmission compared to conventional LTE. Furthermore, beamforming technology may be incorporated into orthogonal frequency division multiplexing (OFDM) as a wireless access technology.

[0078] Additionally, an adaptive modulation and coding (AMC) method that determines a modulation scheme and channel coding rate according to the channel status of the terminal may be applied.

[0079] A new radio core network (NR CN) (3-05) can perform functions such as mobility support, bearer setup, and quality of service (QoS) setup. The NR CN is a device that handles various control functions as well as mobility management functions for terminals 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 can be connected to the mobility management entity (MME) (3-25) through a network interface. The MME can be connected to an eNB (3-30), which is an LTE base station.

[0080] 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.

[0081] Referring to FIG. 4, the wireless protocol of the next-generation mobile communication system may be composed of NR Service Data Adaptation Protocol (SDAP) (4-01, 4-45), NR Packet Data Convergence Protocol (NR PDCP) (4-05, 4-40), NR Radio Link Control (NR RLC) (4-10, 4-35), NR Medium Access Control (NR MAC) (4-15, 4-30), and NR PHY (4-20, 4-25) in the terminal and the new radio (NR) base station, respectively.

[0082] The main functions of the NR Service Data Adaptation Protocol (NR SDAP) (4-01, 4-45) may include some of the following functions:

[0083] Transfer of user plane data

[0084] Mapping function between a QoS flow and a DRB for both DL and UL

[0085] QoS flow ID marking function for both uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0086] Ability to map relective QoS flow to data bearer for the UL SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0087] 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.

[0088] The main functions of the NR Packet Data Convergence Protocol (NR PDCP) (4-05, 4-40) may include some of the following functions:

[0089] - Header compression and decompression (ROHC only)

[0090] - User data transfer function

[0091] - In-sequence delivery of upper layer PDUs

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

[0093] - PDCP PDU reordering for reception

[0094] - Duplicate detection of lower layer SDUs

[0095] - Retransmission function (Retransmission of PDCP SDUs)

[0096] - Encryption and decryption functions (Ciphering and deciphering)

[0097] - Timer-based SDU discard in uplink.

[0098] 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.

[0099] The main functions of NR Radio Link Control (NR RLC)(4-10, 4-35) may include some of the following functions:

[0100] - Data transfer function (Transfer of upper layer PDUs)

[0101] - In-sequence delivery of upper layer PDUs

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

[0103] - ARQ function (Error Correction through ARQ)

[0104] - Concatenation, segmentation and reassembly of RLC SDUs

[0105] - Re-segmentation of RLC data PDUs

[0106] - Reordering of RLC data PDUs

[0107] - Duplicate detection function

[0108] - Protocol error detection

[0109] - RLC SDU discard function

[0110] - RLC re-establishment function

[0111] 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.

[0112] 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.

[0113] 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.

[0114] The in-sequence delivery function of the NR RLC device may include a function to deliver all RLC SDUs received before a predetermined timer starts to the upper layer in sequence, even if there are lost RLC SDUs, if the timer has expired.

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

[0116] 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).

[0117] 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.

[0118] 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.

[0119] In the above, the out-of-sequence delivery function of the NR RLC device may mean 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 the RLC SN or PDCP SN of the received RLC PDUs and arranging the order to record the lost RLC PDUs.

[0120] NR Medium Access Control (NR MAC) (4-15, 4-30) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of NR MAC can include some of the following functions.

[0121] - Mapping function (Mapping between logical channels and transport channels)

[0122] - Multiplexing / demultiplexing of MAC SDUs

[0123] - Scheduling information reporting function

[0124] - HARQ function (Error correction through HARQ)

[0125] - Priority handling between logical channels of one UE

[0126] - Priority handling between UEs by means of dynamic scheduling

[0127] - MBMS service identification function

[0128] - Transport format selection function

[0129] - Padding function

[0130] The NR physical layer (NR PHY layer) (4-20, 4-25) can perform operations such as 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.

[0131] FIG. 5 is a block diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0132] Referring to the above drawing, the terminal may include an RF (Radio Frequency) processing unit (5-10), a baseband processing unit (5-20), a storage unit (5-30), and a control unit (5-40).

[0133] The RF processing unit (5-10) above can perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (5-10) can up-convert a baseband signal provided from the baseband processing unit (5-20) into an RF band signal and transmit it through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (5-10) can 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 the drawing, only one antenna is shown, but the terminal can be equipped with multiple antennas. In addition, the RF processing unit (5-10) can include multiple RF chains. Furthermore, the RF processing unit (5-10) can perform beamforming. For the above beamforming, the RF processing unit (5-10) 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 can receive multiple layers when performing the MIMO operation.

[0134] The baseband processing unit (5-20) above can perform 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 (5-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (5-20) can restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (5-10). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (5-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures 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 (5-20) divides the baseband signal provided from the RF processing unit (5-10) 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.

[0135] The baseband processing unit (5-20) and the RF processing unit (5-10) can transmit and receive signals as described above. Accordingly, the baseband processing unit (5-20) and the RF processing unit (5-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (5-20) and the RF processing unit (5-10) 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 (5-20) and the RF processing unit (5-10) 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.

[0136] The storage unit (5-30) can store data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (5-30) can store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit (5-30) can provide the stored data at the request of the control unit (5-40).

[0137] The control unit (5-40) can control the overall operations of the terminal. For example, the control unit (5-40) transmits and receives signals through the baseband processing unit (5-20) and the RF processing unit (5-10). In addition, the control unit (5-40) records and reads data in the storage unit (5-40). For this purpose, the control unit (5-40) can include at least one processor. For example, the control unit (5-40) can include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0138] FIG. 6 is a block diagram illustrating the structure of a new radio (NR) base station according to one embodiment of the present disclosure.

[0139] As shown in the above drawing, the base station may include an RF (radio frequency) processing unit (6-10), a baseband processing unit (6-20), a backhaul communication unit (6-30), a storage unit (6-40), and a control unit (6-50).

[0140] The RF processing unit (6-10) above can perform functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. The RF processing unit (6-10) can up-convert a baseband signal provided from the baseband processing unit (6-20) into an RF band signal and transmit it through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (6-10) can 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 the drawing, only one antenna is shown, but the first access node can have multiple antennas. In addition, the RF processing unit (6-10) can include multiple RF chains. Furthermore, the RF processing unit (6-10) can perform beamforming. For the above beamforming, the RF processing unit (6-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform a downlink MIMO operation by transmitting one or more layers.

[0141] The baseband processing unit (6-20) above can 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 (6-20) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (6-20) can restore a reception bit stream by demodulating and decoding a baseband signal provided from the RF processing unit (6-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (6-20) can 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.

[0142] In addition, when receiving data, the baseband processing unit (6-20) divides the baseband signal provided from the RF processing unit (6-10) into OFDM symbol units, restores signals mapped to subcarriers through FFT operation, and then restores the received bit string through demodulation and decoding. The baseband processing unit (6-20) and the RF processing unit (6-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (6-20) and the RF processing unit (6-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0143] The above backhaul communication unit (6-30) provides an interface for communicating with other nodes within the network. The above backhaul communication unit (6-30) can convert a bit string transmitted from the main base station to other nodes, such as auxiliary base stations or core networks, into a physical signal, and can also convert a physical signal received from the other nodes into a bit string.

[0144] The storage unit (6-40) can store data such as basic programs, application programs, and setting information for the operation of the main base station. In particular, the storage unit (6-40) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (6-40) can store information that serves as a judgment criterion for whether to provide or terminate multiple connections to a terminal. In addition, the storage unit (6-40) provides the stored data at the request of the control unit (6-50).

[0145] The control unit (6-50) can control the overall operations of the base station. For example, the control unit (6-50) can transmit and receive signals through the baseband processing unit (6-20) and the RF processing unit (6-10) or through the backhaul communication unit (6-30). In addition, the control unit (6-50) records and reads data in the storage unit (6-40). For this purpose, the control unit (6-50) can include at least one processor.

[0146] The following terms and abbreviations may be used throughout the specification.

[0147] - Master node: master node (MN)

[0148] - Secondary node (SN)

[0149] - Conditional PSCell addition and change (CPAC)

[0150] The terminal may have the ability to add a related PSCell (CPA: Conditional PSCell addition) or change to a related PSCell (CPC: Conditional PSCell change) when certain conditions are satisfied.

[0151] - Addition and modification of subsequent (or subsequent) conditional PSCells: subsequent CPAC (subsCPAC, SCPAC)

[0152] Continuous CPAC may refer to the ability to continuously perform CPAC operations without separate network configuration operations even after a terminal moves to a specific PSCell.

[0153] In the sequential conditional PSCell addition and change (subsequent CAPC, SCPAC) operation currently being considered, when the terminal performs the SCPAC operation, all conditional mobility configurations that are not related to (or irrelevant to) the SCPAC configuration (SCAPC config) are deleted (or erased). Afterwards, for all conditional reconfiguration entries that are not deleted (or remain), only the conditional information for all target cells associated with SCPAC is updated. The SCAPC operation currently being considered is performed under the assumption that all SCPAC target cells are capable of moving to each other.

[0154] However, from a network perspective, admission control for a specific candidate SN may not always be bidirectional. That is, due to resource occupancy conditions of the SN or asymmetry between signals of the UE, bidirectional mobility may not always be guaranteed between target PSCells corresponding to SCPAC configurations. In such a case, when the UE performs SCPAC and updates the next SCPAC configuration based on the corresponding cell, the condition information for the target PSCell to which it cannot move is outdated information. Therefore, a problem arises where the outdated condition information does not match the measurement and condition evaluation operations actually performed by the UE.

[0155] The purpose of this disclosure is to address the aforementioned issues. Below, we describe a situation where terminal bidirectional mobility is not guaranteed (a unidirectional mobility situation) and specific methods for resolving this situation.

[0156] FIG. 7A is a diagram illustrating mobility between target cells in a subsequent conditional PSCell addition and change (SCPAC) according to one embodiment of the present disclosure.

[0157] More specifically, FIG. 7a is a diagram for comparing and explaining a situation in which mobility between SCPAC target cells may become a problem in a situation in which subsequent conditional PSCell addition and change (SCPAC) is performed.

[0158] The left diagram illustrates a case where all SCPAC candidate cells are set to allow mutual mobility (Bidirectional mobility).

[0159] On the other hand, the drawing on the right illustrates a case where a condition is set that prevents movement to a specific PSCell (Undirectional mobility).

[0160] According to one embodiment of the present disclosure, a high-level proposal for performing SCPAC operation in a unidirectional mobility situation is as follows.

[0161] 1. If movement is not permitted among the candidate cells of SCPAC

[0162] Among the candidate cells for SCPAC, cells that are not allowed to move can be indicated within the SCPAC configuration transmitted by the network.

[0163] The terminal can perform SCPAC and update information on terminal variables for performing SCPAC measurement and / or evaluation operations in a target cell. At this time, the terminal may not perform condition evaluation and / or measurement operations corresponding to conditions for cells to which movement is not permitted, based on indications of cells to which movement is not permitted in the SCPAC configuration information.

[0164] 2. If movement of candidate cells in SCPAC is always permitted.

[0165] If the SCPAC does not allow the candidate cells to be migrated, each candidate SN and the source SN must create the conditions necessary to migrate to another SCPAC candidate PSCell. More specifically, during the SCPAC setup preparation period, each candidate SN must create (or must create) the conditions necessary to migrate from its candidate PSCells to all other SCPAC candidate PSCells for the PSCells determined as SCPAC candidates. In other words, there must not be a case where the conditions necessary to migrate from a specific candidate PSCell to any other candidate PSCell are not created.

[0166] FIG. 7b is a diagram illustrating a method for setting and updating subsequent conditional PSCell addition and change (SCPAC).

[0167] Referring to FIG. 7, FIG. 7 is a diagram illustrating a method for configuring subsequent conditional PSCell addition and change (SCPAC) to a terminal currently under consideration and a method for updating SPAC settings (or setting information) in a terminal when the terminal performs SCPAC.

[0168] In order to receive SCPAC settings from the network (or base station), the terminal can receive settings such as those in Figure 7b in the conditional Reconfiguration field of RRCReconfiguration of the serving cell.

[0169] The conditional Reconfiguration field (The IE ConditionalReconfiguration is used to add, modify and release the configuration of conditional reconfiguration.) set to the terminal may include condReconfig ID (The IE CondReconfigId is used to identify a CHO, CPA or CPC configuration.), initial condition, condRRCReconfig (The RRCReconfiguration message to be applied when the condition(s) are fulfilled), and SCPAC configuration.

[0170] Each condReconfig ID represents configuration information for a specific target PSCell, where the configuration information may be a delta configuration for the reference configuration. When this configuration information is applied, i.e., as an execution condition that needs to be fulfilled in order to trigger the execution of a conditional reconfiguration for SCPAC for the corresponding target PSCell, up to two measurement IDs (or MeasIds) may be set. In this case, the measurement ID must be one of the measurement IDs set in the measurement configuration of the serving cell for the condition execution of the current conditional reconfiguration. In addition, the SCPAC configuration (SPCAC config) may be added to the corresponding condReconfig Id.

[0171] For convenience, condReconfig id, initial condition, and condRRCReconfig can be called the initial configuration, and the other SCPAC configs can be called the subsequent configurations.

[0172] For each condReconfig Id of the initial configuration, SCPAC settings may or may not be added. If SCPAC settings are not added to each condReconfig Id of the initial configuration, it may mean a general conditional handover, a conditional PSCell change (CPC), and / or a conditional PSCell addition (CPA). If SCPAC settings are added to each condReconfig Id of the initial configuration, the corresponding condReconfig Id of the initial configuration and the target cell of the target cell configuration may mean a target cell that can perform SCPAC.

[0173] For example, in Fig. 7b, each of cond Reconfig Id 1, 2, 3, and 4 of each initial configuration contains SCPAC config. Therefore, the target cells that can perform SCPAC can be PSCell 1, PSCell 2, PSCell 3, and PSCell 4, which correspond to the target PSCells of condReconfigId 1, 2, 3, and 4, respectively.

[0174] Referring to Fig. 7b, it illustrates a case where the current terminal receives the configuration in the drawing when the serving PSCell is PSCell 4. The terminal can store the above information in the terminal variable for conditional reconfiguration. In addition, the condition information among the initial configurations corresponding to each condReconfig Id can be evaluated. If the condition corresponding to PSCell 1 among the conditions is satisfied, the terminal can perform SCPAC operation from PSCell 4 to PSCell 1.

[0175] When the terminal performs each SCPAC operation, the terminal can update the initial configuration by utilizing the information in the SCPAC config. In particular, for each condReconfig Id in the SCPAC config, the terminal can replace the condition information corresponding to the same condReconfig Id in the initial configuration with each condition information (measurement Id) associated with the corresponding id.

[0176] For example, if the terminal satisfies the conditions for performing SCPAC with PSCell 1 and performs SCPAC with PSCell 1, the conditions indicated by each cond reconfig Id in the initial configuration are replaced with the conditions linked to each condReconfig Id in the SCPAC config corresponding to PSCell 1, that is, the meas ids.

[0177] More specifically, referring to FIG. 7b, if the terminal satisfies the conditions for performing SCPAC with PSCell 1 and performs SCPAC with PSCell 1, the conditions corresponding to each condReconfigId in the initial configuration can be updated (or replaced) based on the SCPAC config (condReconfigId 3 - measId (1..2), condReconfigId 2 - measId (1..2), condReconfigId 4 - measId (1..2)) included in condReconfigId 1.

[0178] The above replacement means that since the PSCell has changed from PSCell 4 to PSCell 1, the conditions for moving the information stored in the terminal variables from the corresponding PSCell 1 to each PSCell 3, 2, and 4 must be changed (or replaced). At this time, the SCPAC config of the corresponding PSCell 1 means that the conditions for moving from PSCell 1 to another PSCell (e.g., PSCell 3, PSCell 2, PSCell 4) have already been included in the SCPAC config and transmitted to the terminal.

[0179] As shown in Fig. 7b, the condReconfig ids that include and contain SCPAC config are 1, 2, 3, and 4, and each target PSCell is also PSCell 1, PSCell 2, PSCell 3, and PSCell 4. In addition, even if a movement is made to any of the PSCells among PSCell 1, PSCell 2, PSCell 3, and PSCell 4, the movement is possible among all PSCells that have other SCPAC settings.

[0180] Referring to the currently illustrated drawing 7b, when the terminal has moved to PSCell 1, there are conditions for the terminal to move to PSCell 3, PSCell 2, and PSCell 4 (e.g., condReconfigId 3 - measId (1..2), condReconfigId 2- measId (1..2), condReconfigId 4- measId (1..2)), so it is possible to move from PSCell 1 to PSCell 3, PSCell 2, and PSCell 4.

[0181] If the terminal moves to PSCell 2, the terminal can move to PSCell 1, PSCell 3, or PSCell 4 because there are conditions for moving to PSCell 1, PSCell 3, or PSCell 4 (e.g., condReconfigId 1 - measId (1..2), condReconfigId 3 - measId (1..2), condReconfigId 4 - measId (1..2)).

[0182] In the same way, we assume that mobility is always possible between PSCells with SCPAC config.

[0183] FIG. 8 is a diagram illustrating a method for setting up a subsequent conditional PSCell addition and change (SCPAC) according to an embodiment of the present disclosure.

[0184] From a network perspective, the assumption that condReconfig Id containing SCPAC config can always move between target PSCells may not be correct.

[0185] More specifically, the SCPAC configuration (SCPAC config) based on the target cell where the terminal performed SCPAC may not include condition information and / or condReconfigId for performing (or moving) SCPAC from the target cell where SCPAC was performed to another target cell. In this case, when the terminal performs SCPAC as described above in FIG. 7b and updates the SCPAC configuration (SCPAC config) based on the target cell where SCPAC was performed to the terminal variables, the condReconfig Id and its condition information in the initial configuration associated with the condReconfig Id that does not exist in the SCPAC config are not updated and the previously set measId is maintained as is. Therefore, evaluating the conditions based on the previously set measId that is not updated not only does not match the measConfig set in the target cell, but is also problematic because it is composed of completely different management objects (MOs) and reportconfigs.

[0186] For example, as illustrated in FIG. 8, when a terminal whose current serving PSCell is PSCell 4 moves to PSCell 1, the related SCPAC config may not contain condition information for moving to PSCell 2 and / or condReconfig id (condReconfigId 2, measId (1..2) in SCPAC config included in condReconfigId1 of the initial configuration). Therefore, when the terminal performs (or moves) SCPAC from PSCell 4 to PSCell 1, the condition of condReconfigId 2 in the initial configuration is not updated when the terminal updates the terminal variables. That is, the terminal retains the conditions set in the existing PSCell 4 with respect to condReconfigId 2 in the initial configuration, and accordingly, information about the source cell and the target cell is incorrectly set in the variables of the terminal.

[0187] Therefore, in order to solve this problem, the present disclosure proposes a method of indicating, within the SCPAC configuration transmitted by the network, the cell(s) from which movement is not permitted among the candidate cells of SCPAC. As a method for solving this problem, Option 1-1, Option 1-2, and Option 2-1, Option 2-2 are proposed.

[0188] opt 1. Conditions for moving to a target cell that are not allowed within the SCPAC config can be omitted.

[0189] If a condition for moving to a target cell that is not allowed within the SCPAC config is omitted, the condition, i.e., measId and / or the condReconfig Id associated with the condition may be omitted. Alternatively, the condReconfig id entry of the condition may be omitted, not described, or expressed as not being included.

[0190] When configuring in the network as described above, the terminal can perform SCPAC with a specific target PSCell and compare the condReconfig Id of the config of the SCPAC with the condReconfig Ids that include the SCPAC config in the initial configuration. If there is a part that does not include the condReconfig Id (missing part or nonexistent part) in the SCPAC config compared to the condReconfig Ids that include the SCPAC config in the initial configuration, the terminal can regard the condReconfig ID of the part that is not included (missing part or nonexistent part) as omitted.

[0191] According to the above-described method, when a terminal performs SCPAC to move to a specific target PSCell and updates terminal variables accordingly, the following operations may be performed. Before performing the following operations, the terminal may delete (or erase) all entries of condReconfig Ids that do not contain SCPAC config in the terminal variables. Then, the following operations may be performed.

[0192] 2> if theRRCReconfigurationmessage is applied due to a conditional reconfiguration execution and thesubsequentCondReconfigis included in the entry inVarConditionalReconfigcontaining theRRCReconfigurationmessage: 3> for eachcondReconfigIdincluded incondExecutionCondToAddModListwithinsubsequentCondReconfig: 4> replace (if condReconfig Id exists)condExecutionCondorcondExecutionCondSCGwithin theVarConditionalReconfigor add with (if condReconfig Id not exists) the value received for thiscondReconfigId; 3> for eachcondReconfigIdnot included incondExecutionCondToAddModListwithinsubsequentCondReconfig: 4> removecondExecutionCondorcondExecutionCondSCGwithin theVarConditionalReconfigfor thiscondReconfigId; 3> initiate the conditional reconfiguration evaluation procedure, as specified in 5.3.5.13.4;

[0193] That is, when the terminal performs SCPAC and applies an RRCReconfig message corresponding to the target PSCell configuration, the condition information can be changed by comparing each condReconfig Id in the SCPAC config associated with the target cell with the condReconfig ID in the current terminal variable, conditional Reconfiguration.

[0194] In detail, if the condReconfig ID in SCPAC config is the same as the condReconfig ID in the conditional Reconfiguration terminal variable, the condition information of the condReconfig ID in the conditional Reconfiguration terminal variable can be updated (or replaced) with the condition information associated with the condReconfig ID in SCPAC config.

[0195] If the condReconfig ID in SCPAC config does not exist in the conditional Reconfiguration terminal variable, add the ID to the conditional Reconfiguration terminal variable and also add the related condition information.

[0196] If a condReconfig ID that does not exist in the SCPAC config exists in the conditional Reconfiguration terminal variable, the terminal may remove the entry of the corresponding id (i.e., the ID and its associated condition information and its associated candidate cell configuration information) in the Conditional Reconfiguration terminal variable according to the method of opt 1-1.

[0197] Afterwards, the terminal can perform condition evaluation based on the updated conditions. During the condition evaluation, the condReconfig ID can identify the applicable cell through target cell configuration information. However, since there is no condition information corresponding to the cond Reconfig ID, a specific condition cannot be identified. Accordingly, the terminal cannot perform the condition evaluation.

[0198] In the same case, opt 1-2 can include a 1-bit indicator in the entry of the corresponding id. For example, if the indicator is called not_available, the indicator can be added and stored in the entry of the corresponding cond Reconfig id in the terminal variable.

[0199] In this case, in the terminal condition evaluation operation, among the cond Reconfig Ids of the current terminal variable, for the cond Reconfig Ids that are not linked to not_available, an applicable cell can be identified from the target cell configuration, and an evaluation operation can be performed according to the event of reportconfig that configures the measId from the measIds for the condition linked to the id.

[0200]

[0201] In this case, the terminal variable still stores the measId information as a condition set in the previous cell in the omitted condReconfig Id, but it is excluded (or dropped) from the terminal's condition evaluation operation.

[0202] To address the aforementioned issues, the SCPAC configuration transmitted by the network can indicate among SCPAC candidate cells that are not permitted to move. As a method for this, opt 2 is proposed.

[0203] opt 2-1. Within the SCPAC config, a 1-bit indicator can be explicitly specified in the entry of condReonfig Id that targets (or points to) an unacceptable cell. For example, the 1-bit indicator can be Not_Available (or no_available indicator). The following ASN.1 example is possible.

[0204]

[0205] In case of Option 2-1, when the terminal performs SCPAC and updates the current terminal variables with the information in the SCPAC config of the corresponding target cell, all condReconfig Ids of all initial configurations (or information stored in the current terminal variables) can be updated (or replaced) with the information of all condReconfig Ids in the SCPAC config of the target cell. Accordingly, the condReconfig Id entry for the target PSCell where movement is not allowed includes the not_available indicator.

[0206] After this, the terminal performs condition evaluation based on the updated (or replaced) terminal variables. For condReconfig Ids without the not_available directive, the terminal can identify the target cell and recognize it as an applicable cell, and perform evaluation operations based on the conditional event based on the measId associated with the CondReconfigId.

[0207] Specifically, it is as follows.

[0208]

[0209] Meanwhile, the terminal may not perform condition evaluation operations for condReconfig Ids that include the not_available directive.

[0210] Opt 2-2. As network-directed information, a 1-bit indicator may be included in the condition information for going to a target cell that is not allowed in the SCPAC config instead of the condition information.

[0211] The aforementioned Opt 2-1 maintains the existing information as is, but adds a 1-bit indicator, whereas in this case, the information structure including the condition is a SEQUENCE or CHOICE structure, and can include condition information or a 1-bit indicator. In addition, this structure is a structure at the same level as condReconfig Id, and by including a condition or indicator within it, the operation of "replacing" the contents of the structure can be used as is in the variable update operation of the terminal.

[0212]

[0213] The following is an example of an operation in which, when a terminal performs SCPAC and updates terminal variables, the condition structure of the corresponding entry for each condReconfig Id of SCPAC config is replaced with conditions for each condReconfig Id of the current terminal variable. The internal contents of this condition may be a measure for the actual condition or a 1-bit indicator.

[0214]

[0215] When the above terminal performs terminal variable update, the condition for each condReconfig Id on the terminal variable may include a not_available indication. In the condition evaluation operation of the terminal, the terminal can perform the condition evaluation operation only for condReconfig Id that does not have the corresponding indicator (e.g., not_available indication).

[0216]

[0217] FIG. 9 is a diagram illustrating a method for a network to set up subsequent conditional PSCell addition and change (subsequent CPAC, SCPAC) to a terminal according to an embodiment of the present disclosure.

[0218] Referring to FIG. 9, FIG. 9 illustrates a process in which a network sets up successive conditional PSCell additions and changes (subsequent CPAC, SCPAC) to a terminal.

[0219] First, the user equipment (UE) may be in a dual connectivity situation with a master node (MN) and a source-secondary node (S-SN).

[0220] In step 10, the S-SN (e.g., SN1) may transmit an SN change required message to the MN. More specifically, the S-SN may transmit (or forward) to the MN an SN change required message including at least one of an indicator indicating the start of SCPAC, list information recommending candidate PSCells operated by each candidate SN, and information on a condition for moving to each proposed candidate target PSCell based on the source PSCell.

[0221] In step 20 (or step 40), the MN may send an SN addition request message (e.g., an SNAdd request message) to at least one candidate SN (e.g., SN2, SN3).

[0222] More specifically, the MN can transmit at least one candidate PSCell (or list information recommending candidate PSCells operated by the candidate SN) received from the S-SN (SN1) to each candidate SN. In addition, the MN can also simultaneously transmit (or forward) information on candidate PSCells recommended by the S-SN (SN1) among the cells of other candidate SNs.

[0223] In step 30 (or step 50), at least one candidate SN (e.g., SN2, SN3 may be included) may transmit an SN addition request acknowledge message (e.g., SNAddReqACK) to the MN.

[0224] The above at least one candidate SN may send an SN addition request acknowledge message including information about the admitted PSCell candidate to the MN and condition information to be used for moving to the proposed PSCell.

[0225] Each candidate SN can perform admission control among at least one candidate PSCell recommended by the MN to determine a prepared PSCell and a target configuration to be used in the cell. (The target configuration is referred to as a delta configuration here and can be used later in the terminal along with the reference configuration.)

[0226] Additionally, each candidate SN may transmit (or forward) to the MN an SN addition request acknowledge message (e.g., an AddReqACK message) including condition information to be used for moving to another cell among the recommended candidate PSCells of other candidate SNs and / or its own prepared PSCell in that cell.

[0227] Among these, each candidate SN can also prepare conditions for moving from its cell to the candidate PSCell of another candidate SN. At this time, each candidate SN can accept or reject the movement from its prepared PSCell to the candidate PSCell of a specific candidate SN.

[0228] If the candidate SN accepts the movement from its prepared PSCell to the candidate PSCell of a specific candidate SN, the candidate SN may add condition information for the movement from its prepared PSCell to the candidate PSCell of the specific candidate SN to the SN addition request acknowledge message.

[0229] If a candidate SN does not accept (or rejects) a move from its prepared PSCell to a candidate PSCell of a specific candidate SN, the condition information may not be included in the SN addition request acknowledge message.

[0230] For example, if a migration from any admitted PSCell of SN2 to PSCell 2 is not allowed, the SN addition request acknowledge message sent by SN2 to MN will not include the condition information for migration to that PSCell 2.

[0231] Additionally, although the current drawing depicts steps 20, 30, 40, and 50 in that order, the scope of the present invention is not limited thereto. More specifically, at least one of steps 20 and 40 may be performed. Steps 20 and 40 may be performed simultaneously, step 40 may be performed after step 20, or step 20 may be performed after step 40. Steps 30 and 50 may be performed after steps 20 and 40, respectively.

[0232] In step 60 (or step 80), the MN may transmit an SN modification request message (e.g., an SN MODReq message) to at least one candidate SN (e.g., SN2, SN3).

[0233] More specifically, the MN receives the information from each candidate SN, and if not all recommended PSCells are prepared in each candidate SN, the MN can transmit (or forward) information about the prepared PSCells to each candidate SN and SN again. At this time, the SNModReq message can be used.

[0234] In step 70 (or step 90), at least one candidate SN (e.g., SN2, SN3 may be included) may transmit an SNN modification request acknowledge message (e.g., SNMODReqACK message) to the MN.

[0235] More specifically, each candidate SN and S-SN that receives the SN modification request message updates the condition information considering only the prepared (i.e., admitted) PSCells from the candidate PSCells for which it is recommended (i.e., if conditions for all candidate PSCells have been previously created, some of them are removed), and updates the measurement configuration including the condition information (i.e., for the combination of MO and reportconfig for the conditions of all candidate PSCells previously, some are removed except for those for prepared candidate cells), so that the target cell configuration including the conditions and measurement configuration for only the admitted (prepared) PSCells can be transmitted (or forwarded) to the MN through an SN modification request acknowledge message (e.g., SNModReqACK) message.

[0236] Additionally, although the current drawing depicts steps 60, 70, 80, and 90 in that order, the scope of the present invention is not limited thereto. At least one of steps 60 and 80 may be performed. Steps 60 and 80 may be performed simultaneously, step 80 may be performed after step 60, or step 60 may be performed after step 80. Steps 70 and 90 may be performed after steps 60 and 80, respectively.

[0237] In steps 100 and / or 110, the MN can transmit reference configuration and target PSCell configuration information to the UE. (MN identifies complete SN RRCReconfnig, then it generates MN counterpart. Configured UE with ref and delta (complete) configuration)

[0238] More specifically, the MN may store (or have) a reference configuration that it generates (creates) or that the S-SN generates (creates) and transmits in step 10. The MN may transmit (or have) the reference configuration and target PSCell configuration setting information received from each candidate SN to the UE. The MN may transmit an RRC reconfiguration including the reference configuration and a candidate configuration list to the UE.

[0239] After receiving this, when the terminal wants to perform SCPAC to a specific target cell, it applies a complete configuration that adds and / or combines the target PSCell configuration to the reference configuration.

[0240] The MN can receive this information and ultimately assign / map condition information and target cell configuration information for target PSCells to condReconfig Ids and deliver them to the UE. At this time, SCPAC settings (SCPAC config) can be added to each condReconfig Id (or additionally mapped).

[0241] For example, if the migration to PSCell 2 of SN2 is not decided in the above step 30, then depending on the result, the SCPAC config of missing PSCell 2 may be displayed in the SCPAC config in the case of migration from the current source PSCell to the corresponding PSCell of SN2.

[0242] In step 120, in response to receiving the RRC reset message, the terminal can transmit an RRC reset complete message to the MN.

[0243] Afterwards, the terminal can perform measurement and condition evaluation operations. (UE measure and evaluate the condition)

[0244] If certain conditions are met, the UE can perform SCPAC. During SCPAC, the UE can update UE variables. (If one condition is met, the UE executes SCPAC, and during execution, the UE updates UE variables.)

[0245] If SN2 has not decided to move to PSCell 2, the UE can update its variables by considering that PSCell 2 is not allowed as a target cell. (UE update UE variable by considering PSCell 2 is not allowed target cell)

[0246] If the SCPAC does not allow the candidate cells to be moved, the operation may be as follows when the conditions required for each candidate SN to move from its candidate PSCell(s) to all SCPAC candidate pscELLs determined as SCPAC candidates are created.

[0247] There may be cases where SCPAC does not allow a candidate cell to be migrated. In such cases, each candidate SN must, during the SCPAC setup preparation period, create (or establish) the conditions necessary for migrating from its candidate PSCells to all other SCPAC candidate PSCells for all PSCells proposed by the S-SN that have been determined as SCPAC candidates. In other words, there must not be a case where a condition necessary for migrating from a specific candidate PSCell to any other candidate PSCell is not created.

[0248] In order to not allow the case where the candidate cells of SCPAC are not moved, each candidate SN including the S-SN may decide whether to allocate SCPAC resources to the proposed candidate PSCells under its control (or jurisdiction) as determined by the S-SN itself or as transmitted from the S-SN through the MN, and then perform the following actions for each PSCell to which it has decided to allocate resources.

[0249] - When moving from itself (each PSCell above) to all PSCells below, it must always generate (or create) condition information that must be evaluated, and transmit it to the MN for the purpose of configuring the terminal. Here, the PSCell below may mean PSCells other than itself among the PSCells to which the same candidate SN has decided to allocate SCPAC resources, and PSCells to which other candidate SNs have been proposed by the S-SN and decided to allocate resources.

[0250] Hereinafter, a specific description will be made with reference to the call flow of Fig. 9. Referring to Fig. 9, at least one candidate SN (e.g., SN2 or SN3) will generate (or create) a condition that applies to moving to all proposed candidate PSCells of other candidate SNs acquired (or given) in steps 20 or 40, for each PSCell to which it decides to allocate resources among the PSCells proposed in steps 20 or 40. In addition, the measurement object (MO) and report config settings corresponding to this condition must be included in the target cell configuration of each PSCell to which it decides to allocate resources.

[0251] After step 50, the MN can receive information about the candidate PSCells to which all candidate SNs have decided to allocate resources.

[0252] In step 60 or 80, the MN can transmit (or forward) this information back to the SNs (candidate SNs and S-SNs), so that the SNs can recognize the candidate PSCells that are actually admission controlled, clear the condition information for moving to the remaining PSCells, leaving only the recognized PSCells, and clear the associated measurement configuration.

[0253] In step 70 or 90, each candidate SN can transmit (or forward) the final determined measurement configuration and the deleted (or erased) condition information or the remaining condition information back to the MN. This information can be used by the MN to transmit (or forward) the SCPAC configuration to the terminal.

[0254] The above MN must include, in the conditional Reconfiguration information set to the terminal, all cond Reconfig Ids that contain SCPAC configurations, and in each SCPAC configuration, all ids other than its own condReconfig Id and the condition information associated with them.

[0255] (conditions for moving to all other SCPAC candidate PSCells should be present in each SCPAC configuration.)

[0256] After receiving the above network settings, if necessary, a specific candidate SN may find it difficult to invest resources in SCPAC settings for the corresponding terminal any more. In such a case, the terminal that finds it difficult to invest resources in SCPAC settings for the corresponding terminal any more may notify the MN of this via an Xn message. The Xn message may include an SN change request message (e.g., SNChangeRequest), an SN modification request message (e.g., SNModRequest), an SN modification required message (e.g., SNModRequired), or a new message.

[0257] At this time, a specific candidate SN may notify the withdrawal of resource allocation for a specific candidate PSCell operated by the candidate SN. To this end, the specific candidate SN may transmit (or forward) to the MN the physical cell identity (PCI) / absolute radio-frequency channel number (AFRCN) value of the candidate PSCell for which resource allocation is to be withdrawn (or has been withdrawn).

[0258] After receiving this, the MN can notify the S-SN and candidate SNs of the withdrawal of resource allocation for a specific candidate PSCell operated by a specific candidate SN through an Xn message. The Xn message can include an SN add requests message (e.g., SNAddReq) or an SN modification request message (SNModReq).

[0259] Each SN may perform actions to update the target PSCell configuration previously transmitted to the MN and / or remove conditions for moving to a candidate PSCell for which allocation is to be withdrawn.

[0260] Afterwards, when each SN transmits (or forwards) the ack message of the above operation to the MN, the MN can transmit (or forward) the corresponding change in the conditionalReconfiguration field in the RRCREconfiguration message to the terminal.

[0261] At this time, the MN may instruct the terminal variable to release the condReconfig Id having the target cell setting for the candidate PSCell to be withdrawn.

[0262] In such a case, the MN shall always instruct the SCPAC config to also release the condReconfig Id entry for the PSCell that is a candidate for withdrawal, for all other condReconfig Ids that have (or contain) the SCPAC config of the terminal variable.

[0263] In the following, we will explain with specific examples.

[0264] The following could be a message that the network would send to the terminal, assuming that PSCell 2 is the target of withdrawal and its condReconfig Id is 2.

[0265]

[0266] FIG. 10 is a diagram illustrating a method for performing sequential conditional PSCell addition and change (subsequent CPAC, SCPAC) to a terminal according to one embodiment of the present disclosure.

[0267] When using one terminal variable, the terminal behaves as follows.

[0268] The UE can apply the RRCReconfiguration message as a target cell configuration associated with the target PSCell whose conditions are satisfied. In this process, the UE deletes all entries of condReconfig Id that are not associated with SCPAC config from the UE variables. The conditions associated with the same condReconfig Id in the current UE variables are overwritten with the conditions associated with the condReconfig Id in the SCPAC config associated with the target PSCell. After this, the UE does not evaluate the conditions associated with the condReconfig Id in the UE variables that are identical to the omitted cond Reconfig Id (or those with the 1-bit indicator) if there is an omitted cond Reconfig Id in the SCPAC config or a 1-bit indicator in the condReconfig Id.

[0269] The terminal operation so far has been exemplified using a single terminal variable as a location for storing conditional mobility settings. However, the use of a single terminal variable increases the complexity of terminal operation. To address this, this disclosure proposes a case where two terminal variables are used.

[0270] When two terminal variables are used, the terminal behaves as follows.

[0271] At the point when SCPAC is set in the terminal of Fig. 7b, the terminal can configure (or set) two variables: a long term variable and a short term variable.

[0272] Long term variables can store movement conditions and target PSCell settings associated with each condReconfig id. Referring to Figure 7b, the terminal can store at least one of the following pieces of information in the long term variable.

[0273] :Initial config part's condReconfig Id, id and its associated condRRCReconfig and SCPAC config (or only the condition information associated with the condReconfig Id in SPCAC config).

[0274] Shorterm variable can store initial part Config information.

[0275] Afterwards, when SCPAC is performed, the terminal can delete (or erase) all entries of the shorterm variable. Then, in the long term variable, for the condReconfig Id in the SCPAC config associated with the target cell on which SCPAC was performed, each cond reconfig id existing in the long term variable and the corresponding condRRCReconfig configuration information can be stored in the shorterm variable. Then, the condition information in the SCPAC config of the corresponding target cell can be added to each condReconfig Id stored in the shorterm variable.

[0276] By using two variables, a long term variable and a shorterm variable, the terminal can update SCPAC condition information that sets the target cell that performed SCPAC as the serving cell using the shorterm variable. Thereafter, the terminal can perform condition evaluation to move to another SCPAC candidate PSCell based on the updated shorterm variable.

[0277] When using the above two variables, a long-term variable and a short-term variable, the release conditions for each entry may be different. For example, the short-term variable may be released at every PSCell change (regardless of SCPAC). Meanwhile, the long-term variable may be released in the event of an RRC connection re-establishment (RRE), an RRC release, or a NW indication.

[0278] According to another embodiment of the present disclosure, based on the following ASN.1 structure, elements of condition lists can be added / modified / released within each SCPAC config.

[0279] If a specific entry among the condReconfig id entries in a specific SCPAC config needs to be deleted, i.e., except for the case of migrating to a specific candidate PSCell (or to eliminate it), the network can delete the corresponding cond Reconfig id by indicating it with the release command. At this time, the same condReconfig Id entry in the initial configuration part, which is currently being evaluated in the terminal variable, can also be deleted. That is, if the migration to the target cell of one SCPAC config cannot be performed, the condReconfig entry for the target cell currently being evaluated may also need to be deleted at the same time.

[0280] As a method for accomplishing this, the present disclosure proposes a method of introducing CondExecutionCondToReleaseList-r18 within SCPAC config. More specifically, when the network deletes a specific condReconfig ID using CondExecutionCondToReleaseList-r18 within SCPAC config, the terminal can automatically delete (or delete) the entry with the same condReconfig ID existing in the current terminal variable.

[0281] In another embodiment of the present disclosure, a method is proposed in which a network performs a CondReconfigToremove command. More specifically, when the network deletes (or erases) a condReconfig id having an SCPAC configuration currently in the terminal variables, the terminal can delete (or erase) the entry of the condReconfig Id in the corresponding SCPAC config for another condReconfig id having an SCPAC config in the terminal variables through the CondReconfigToremove command.

[0282] That is, when deleting an id in a terminal variable or deleting a specific id in a specific SCPAC config, the terminal must perform an action of deleting each entry corresponding to the same condReconfig id in the SCPAC config or in the terminal variable.

[0283] In the above-described embodiment, if the remaining operation of deleting (or erasing) was performed by the terminal itself through one network instruction, in another embodiment of the present disclosure, the network may transmit to the terminal, in one RRCReconfiguration message, a command to delete the entry of id in the terminal variable for the same condReconfig Id and a command to delete the entry of id in a specific SCPAC config.

[0284]

[0285]

[0286] In this specification, condReconfig id is mentioned several times. The condReconfig Id on the terminal variable has the same meaning as the condReconfig id of the initial config part in Fig. 7b, and the condReconfig id may or may not include the SCPAC config.

[0287] 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.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] In this disclosure, the term "computer program product" or "computer-readable medium" is used to collectively refer to media such as memory, a hard disk installed in a hard disk drive, and signals. These "computer program products" or "computer-readable mediums" are components provided in a method for reporting terminal capabilities in a wireless communication system according to the present disclosure.

[0292] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0293] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be at least temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0294] 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.

[0295] 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. A method performed by a terminal of a wireless communication system, A step of obtaining SCPAC configuration information including information about at least one subsequent PSCell addition and change (SCPAC) candidate cell from a base station, the SCPAC configuration information being related to configuration of a cell from which movement is not permitted among the at least one SCPAC candidate cell; A step of determining a cell among the at least one SCPAC candidate cell that does not perform condition evaluation based on the configuration information regarding the SCPAC; A step of performing condition evaluation on cells excluding cells among at least one SCPAC candidate cell that have been decided not to perform condition evaluation; and A method characterized by comprising a step of performing a SCPAC operation based on the above condition evaluation.

2. In paragraph 1, A method characterized in that the SCPAC configuration information does not include condition information (meas Id) of a cell from which movement is not permitted among the at least one SCPAC candidate cell and condition configuration information (condReconfig Id) linked to the condition.

3. In paragraph 2, A method characterized by further comprising a step of deleting an entry related to condition information (meas Id) of a cell from which movement is not permitted among the at least one SCPAC candidate cell stored in a variable of the terminal and condition setting information (condReconfig Id) linked to the condition.

4. In paragraph 2, A method characterized by further comprising the step of adding a condition evaluation operation exclusion indicator (not_available) to an entry related to condition information (meas Id) of at least one SCPAC candidate cell stored in a variable of the terminal and condition setting information (condReconfig Id) linked to the condition of a cell from which movement is not permitted.

5. In paragraph 1, A method characterized in that the SCPAC configuration information further includes an indicator for indicating exclusion of condition evaluation operation for cells from which movement is not permitted among the at least one SCPAC candidate cell.

6. A method performed by a base station of a wireless communication system, generating SCPAC configuration information including information about at least one subsequent conditional primary secondary cell (PSCell) addition and change (SCPAC) candidate cell; and A step of transmitting SCPAC configuration information including information about at least one SCPAC candidate cell to a terminal, A method characterized in that the SCPAC configuration information is related to the configuration of a cell from which movement is not permitted among the at least one SCPAC candidate cell.

7. In paragraph 6, A method characterized in that the SCPAC configuration information does not include condition information (meas Id) of a cell from which movement is not permitted among the at least one SCPAC candidate cell and condition configuration information (condReconfig Id) linked to the condition.

8. In paragraph 6, A method characterized in that the SCPAC configuration information further includes an indicator for indicating exclusion of condition evaluation operation for cells from which movement is not permitted among the at least one SCPAC candidate cell.

9. In the terminal of a wireless communication system, A transceiver for transmitting and receiving signals; and A control unit coupled with the above transmitter and receiver, wherein the control unit comprises: Obtain SCPAC configuration information from a base station, which includes information about at least one subsequent PSCell addition and change (SCPAC) candidate cell, wherein the SCPAC configuration information is related to configuration of a cell from which movement is not permitted among the at least one SCPAC candidate cell; Based on the configuration information about the SCPAC, a cell is determined among at least one SCPAC candidate cell that does not perform condition evaluation, Perform condition evaluation on cells excluding cells that have been decided not to perform condition evaluation among at least one SCPAC candidate cell; A terminal characterized by performing SCPAC operation based on the above condition evaluation.

10. In paragraph 9, A terminal characterized in that the SCPAC configuration information does not include condition information (meas Id) of a cell from which movement is not permitted among the at least one SCPAC candidate cell and condition configuration information (condReconfig Id) linked to the condition.

11. In paragraph 10, the control unit, Delete an entry related to condition information (meas Id) of a cell from which movement is not permitted among at least one SCPAC candidate cell stored in the variable of the terminal and condition setting information (condReconfig Id) linked to the condition, or A terminal characterized in that a condition evaluation operation exclusion indicator (not_available) is added to an entry related to condition information (meas Id) of at least one SCPAC candidate cell stored in a variable of the terminal and condition setting information (condReconfig Id) linked to the condition of a cell from which movement is not permitted.

12. In paragraph 9, A terminal characterized in that the SCPAC configuration information further includes an indicator for indicating exclusion of condition evaluation operation for cells from which movement is not permitted among the at least one SCPAC candidate cell.

13. In a base station of a wireless communication system, A transceiver for transmitting and receiving signals; and A control unit coupled with the above transmitter and receiver, wherein the control unit comprises: Generate SCPAC configuration information including information about at least one subsequent conditional primary secondary cell (PSCell) addition and change (SCPAC) candidate cell, Transmitting SCPAC configuration information including information about at least one SCPAC candidate cell to the terminal, A base station, characterized in that the SCPAC configuration information is related to the configuration of a cell in which movement is not permitted among the at least one SCPAC candidate cell.

14. In paragraph 13, A base station, characterized in that the SCPAC configuration information does not include condition information (meas Id) of a cell from which movement is not permitted among the at least one SCPAC candidate cell and condition configuration information (condReconfig Id) linked to the condition.

15. In paragraph 13, A base station, characterized in that the SCPAC configuration information further includes an indicator for indicating exclusion of a condition evaluation operation for a cell from which movement is not permitted among the at least one SCPAC candidate cell.

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