Method and apparatus for transmitting UE assistance information by a terminal supporting multiple USIMs in a wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The present disclosure provides a method performed by a terminal supporting a multi-universal subscriber identity module (MUSIM) in a wireless communication system, the method including: receiving configuration information related to MUSIM operation from a base station; if the terminal needs to leave an RRC connected state using a first USIM and a timer for state transition is not running, transmitting a UE assistance information message to the base station; and starting the timer for the state transition based on the configuration information related to MUSIM operation.

Description

[Technical field]

[0001] The present disclosure relates to a method and apparatus for transmitting UE assistance information in a wireless communication system. [Background technology]

[0002] 5G mobile communication technology defines a wide frequency band to enable high transmission speeds and new services, and can be implemented not only in the sub-6GHz band, such as 3.5GHz, but also in the ultra-high frequency band, known as mmWave, such as 28GHz and 39GHz, known as 'Above 6GHz'. In addition, in the case of 6G mobile communication technology, known as the Beyond 5G system, implementation in the terahertz band (e.g., 95GHz to 3THz band) is being considered to achieve transmission speeds 50 times faster than 5G mobile communication technology and ultra-low latency times that are one-tenth of those of 5G mobile communication technology.

[0003] In the early stage of 5G mobile communication technology, the goal is to meet the service support and performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and Massive Machine-Type Communications (mMTC). The following technologies have been proposed: Beamforming and Massive MIMO to mitigate the path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves; various numerology support (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 multiple beam transmission and wideband; definition and operation of Band-Width Part (BWP); new channel coding methods such as Low Density Parity Check (LDPC) code for large-volume data transmission and Polar Code for reliable transmission of control information; L2 pre-processing (L2 Standardization has progressed in areas such as network pre-processing, and network slicing, which provides dedicated networks specialized for specific services.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communications technology in consideration of the services that 5G mobile communications technology was intended to support. Physical layer standardization is underway for technologies such as Vehicle-to-Everything (V2X), which assists autonomous vehicles in making driving decisions based on their own position and status information transmitted by the vehicle to increase user convenience, New Radio Unlicensed (NR-U), which aims to operate systems in unlicensed spectrum in accordance with various regulatory requirements, technology to reduce power consumption of NR terminals (UE Power Saving), Non-Terrestrial Network (NTN), which is direct communication between terminals and satellites to ensure coverage in areas where communication with terrestrial networks is not possible, and positioning.

[0005] In addition, standardization is underway in the areas of radio interface architecture / protocol for technologies such as the Industrial Internet of Things (IIoT) to support new services through collaboration and convergence with other industries, Integrated Access and Backhaul (IAB) to provide nodes for expanding network service areas by integrating wireless backhaul links and access links, mobility enhancement technologies including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) to simplify random access procedures. Standardization is also underway in the areas of system architecture / service for 5G baseline architecture (e.g., Service based Architecture, Service based Interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) to provide services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, it is expected that the number of connected devices, which is increasing explosively, will be connected to the communication network, which will require the enhancement of the functions and performance of the 5G mobile communication system and the integrated operation of connected devices.To this end, new research will be conducted on eXtended Reality (XR) to efficiently support Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR), etc., 5G performance improvement and complexity reduction using Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, drone communication, etc.

[0007] In addition, the development of such 5G mobile communication systems will be the basis for the development of multiple antenna transmission technologies such as new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, full dimensional MIMO (FD-MIMO), array antennas, and large scale antennas, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, AI-based communication technology that utilizes satellites and artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to realize system optimization, and next-generation distributed computing technology that utilizes ultra-high performance communication and computing resources to realize services of a complexity that exceeds the limits of terminal computing capabilities.

[0008] With the development of wireless communication systems as described above, it becomes possible to provide various services, and a method for smoothly providing such services is required. In particular, a method for a terminal to efficiently transmit UE assistance information is required.

[0009] The above information is provided solely as background information to aid in the understanding of the present disclosure. No determination or assertion has been made as to which of the above content may be applicable as prior art in connection with the present disclosure. Summary of the Invention [Means for solving the problem]

[0010] Aspects of the present disclosure address at least the problems and / or shortcomings discussed above and provide at least the advantages described below. Accordingly, aspects of the present disclosure provide an apparatus and method for efficiently providing services in a mobile communication system.

[0011] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the presented embodiments.

[0012] According to one embodiment of the present disclosure, a method performed by a terminal supporting a multi-universal subscriber identity module (MUSIM) in a wireless communication system, the method including: receiving configuration information related to MUSIM operation from a base station; if the terminal needs to transition from an RRC connected state using a first USIM and a timer for the state transition is not running, transmitting a UE assistance information message to the base station; and starting the timer based on the configuration information.

[0013] The method may include a step of transitioning from the RRC connected state using the first USIM if no response is received from the base station before expiration of a timer for the state transition after transmitting the UE assistance information.

[0014] The UE assistance information message may include the RRC state preferred by the terminal.

[0015] The method may further include a step of the terminal performing a handover process; if a reconfigurationWithSync parameter is included in the configuration information for the handover process and the UE assistance information is transmitted to the base station within a predetermined time, and the UE assistance information message is configured to be transmitted to a target base station of the handover process, a step of transmitting the UE assistance information message to a target base station of the handover process; and a step of starting or restarting a timer for the state transition.

[0016] The method may further include a step of the terminal performing a handover process; if a reconfigurationWithSync parameter is included in configuration information for the handover process, an RRCReconfiguration message is applied according to a conditional reconfiguration condition, the terminal is configured to provide UE assistance information, and the terminal starts transmitting a UE assistance information message to a target base station of the handover process; and a step of starting or restarting a timer for the state transition.

[0017] The transmitted UE assistance information message includes first preferred MUSIM gap information of the terminal, and the method may include, when the first preferred MUSIM gap information and the second preferred MUSIM gap information currently preferred by the terminal are different from each other and a timer for prohibiting a change of the MUSIM gap is not running, transmitting a UE assistance information message including the second preferred MUSIM gap information based on the determination result; and starting or restarting a timer for prohibiting a change of the MUSIM gap.

[0018] If the second preferred MUSIM gap information is information obtained by excluding only non-periodic MUSIM gap information from the first preferred MUSIM gap information, a UE assistance information message including the second preferred MUSIM gap information may not be transmitted.

[0019] The setting information regarding the MUSIM operation may include parameters regarding a timer for state transition and a timer for prohibiting changes to the MUSIM gap.

[0020] The setting information regarding the MUSIM operation may include MUSIM gap information and information regarding MUSIM connection state switching.

[0021] The method may include receiving an RRC Reestablishment message from the base station; and releasing the MUSIM gap information set based on the configuration information.

[0022] According to one embodiment of the present disclosure, a terminal supporting a multi-universal subscriber identity module (MUSIM) in a wireless communication system, the terminal includes: a transceiver; and at least one processor coupled to the transceiver, the at least one processor may be configured to receive configuration information regarding MUSIM operation from a base station, and when the terminal needs to transition from an RRC connected state using a first USIM and a timer for state transition is not running, to send a UE assistance information message to the base station and start the timer for state transition based on the configuration information regarding the MUSIM operation.

[0023] After transmitting the UE assistance information, if no response is received from the base station before a timer for the state transition expires, transitioning from the RRC connected state using the first USIM may be included.

[0024] The UE assistance information message may include the RRC state preferred by the terminal.

[0025] The at least one processor can, when the terminal performs a handover process, a reconfigurationWithSync parameter is included in the configuration information for the handover process, the UE assistance information is transmitted to the base station within a predetermined time, and the UE assistance information message is configured to be transmitted to a target base station of the handover process, send the UE assistance information message to a target base station of the handover process, and start or restart a timer for the state transition.

[0026] The at least one processor may, when the terminal performs a handover process, a reconfigurationWithSync parameter is included in configuration information for the handover process, an RRCReconfiguration message is applied due to a conditional reconfiguration condition, the terminal is configured to provide UE assistance information, and the terminal starts transmitting a UE assistance information message to a target base station of the handover process, and may start or restart a timer for the state transition.

[0027] The transmitted UE assistance information message includes first preferred MUSIM gap information of the terminal, and the method may include, when the first preferred MUSIM gap information and the second preferred MUSIM gap information currently preferred by the terminal are different from each other and a timer for prohibiting a change of the MUSIM gap is not running, transmitting a UE assistance information message including the second preferred MUSIM gap information based on the determination result; and starting or restarting a timer for prohibiting a change of the MUSIM gap.

[0028] If the second preferred MUSIM gap information is information obtained by excluding only non-periodic MUSIM gap information from the first preferred MUSIM gap information, a UE assistance information message including the second preferred MUSIM gap information may not be transmitted.

[0029] The setting information regarding the MUSIM operation may include parameters regarding a timer for state transition and a timer for prohibiting changes to the MUSIM gap.

[0030] The setting information regarding the MUSIM operation may include MUSIM gap information and information regarding MUSIM connection state switching.

[0031] The at least one processor may receive an RRC Reestablishment message from the base station and release the MUSIM gap information set based on the setting information.

[0032] The present disclosure provides an apparatus and method capable of efficiently providing services in a mobile communication system.

[0033] Other aspects, advantages and distinguishing features of the present disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure. [Brief description of the drawings]

[0034] The above and other aspects, features, and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which: [Figure 1A] FIG. 1 illustrates a structure of an LTE system according to one embodiment of the present disclosure. [Figure 1B] A diagram illustrating a radio protocol structure in an LTE system according to one embodiment of the present disclosure. [Figure 1C] FIG. 1 is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure. [Figure 1D] FIG. 2 is a diagram illustrating a radio protocol structure of a next-generation mobile communication system according to one embodiment of the present disclosure. [Figure 1E] 1 is a flowchart of a process in which a terminal in an RRC connected mode (RRC_CONNECTED) performs measurement based on measurement configuration information set by a base station according to an embodiment of the present disclosure. [Figure 1F]FIG. 1 is a diagram illustrating a terminal (Multi-USIM UE) that supports multiple Universal Subscriber Identity Modules (USIMs) performing operations associated with another USIM while maintaining an RRC connected mode (RRC_CONNECTED) with a base station associated with one USIM, according to one embodiment of the present disclosure. [Figure 1G] FIG. 1 is a diagram illustrating a terminal (Multi-USIM UE) that supports multiple Universal Subscriber Identity Modules (USIMs) releasing an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performing an operation associated with another USIM according to one embodiment of the present disclosure. [Figure 1H] FIG. 1 is a diagram illustrating a terminal (Multi-USIM UE) that supports multiple Universal Subscriber Identity Modules (USIMs) releasing an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performing an operation associated with another USIM according to one embodiment of the present disclosure. [Figure 1I] 1 is a flowchart illustrating an embodiment of the present disclosure in which a terminal (Multi-USIM UE) that supports multiple USIMs (Universal Subscriber Identity Modules) performs an RRC connection re-establishment procedure with a base station associated with one USIM. [Figure 1J] This is a diagram illustrating an operation of transmitting a UE Assistance Information message after a terminal (Multi-USIM UE) that supports multiple USIMs (Universal Subscriber Identity Modules) performs handover or conditional handover from a base station associated with one USIM according to one embodiment of the present disclosure. [Figure 1K] FIG. 2 is a block diagram showing the structure of a terminal according to an embodiment of the present disclosure. [Figure 1L]FIG. 1 is a block diagram illustrating a structure of an NR base station according to one embodiment of the present disclosure. [Figure 1M] FIG. 1 is a diagram illustrating a terminal (Multi-USIM UE) supporting multiple USIMs (Universal Subscriber Identity Modules) according to an embodiment of the present disclosure releasing an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performing an operation associated with another USIM. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The following description with reference to the accompanying drawings is provided to aid in a comprehensive understanding of various embodiments of the present disclosure defined by the claims and their equivalents. Various specific details are included herein to aid in such understanding, but they should be considered merely as examples. Thus, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Also, for clarity and conciseness, descriptions of well-known functions and configurations may be omitted.

[0036] The terms and words used in the following description and claims are not limited to their bibliographical meanings, but are merely used to allow the inventor to clearly and consistently understand the present disclosure. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustrative purposes only, and is not intended to limit the present disclosure as defined by the appended claims and their equivalents.

[0037] Unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" may include plural referents. Thus, for example, reference to a "component surface" includes reference to one or more of such surfaces.

[0038] For the same reason, some components are exaggerated, omitted, or illustrated in a schematic manner in the accompanying drawings. Also, the size of each component does not entirely reflect the actual size. The same or corresponding components in each drawing are denoted by the same reference numerals.

[0039] The advantages and features of the present disclosure, and the methods of achieving them, will become clear by referring to the embodiments described in detail below with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but can be implemented in various different forms, and the embodiments are merely provided to make the present disclosure complete and to allow those skilled in the art to which the present disclosure pertains to fully understand the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

[0040] In this case, it will be understood that each block of the process flow diagram and combination of the flow diagrams may be implemented by computer program instructions. These computer program instructions may be loaded onto a processor of a general purpose computer, a special purpose computer, or other programmable data processing equipment, such that the instructions executed by the processor of the computer or other programmable data processing equipment will generate means for performing the functions described in the flowchart block(s). These computer program instructions may also be stored in a computer usable or computer readable memory that can direct the computer or other programmable data processing equipment to implement the functions in a particular manner, such that the instructions stored in the computer usable or computer readable memory may produce an article of manufacture that embodies the instruction means for performing the functions described in the flowchart block(s). Computer program instructions may also be embodied on a computer or other programmable data processing device such that a sequence of operations is performed on the computer or other programmable data processing device to generate a computer-implemented process such that the instructions operate the computer or other programmable data processing device to provide steps for performing the functions described in the flow diagram block(s).

[0041] Also, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a particular logical function(s). It should also be noted that in some alternative embodiments, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially simultaneously, or the blocks may sometimes be performed in reverse order depending on the relevant functions.

[0042] The term 'module' used in the present embodiment means software or hardware components such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), and the 'module' performs a certain task. However, the 'module' is not limited to software or hardware. The 'module' may be configured to reside on an addressable storage medium or to execute one or more processors. Thus, by way of example, the 'module' includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided in the 'module' may be combined into fewer components and 'modules' or further separated into additional components and 'modules'. Moreover, the components and 'modules' may be implemented to execute one or more CPUs in a device or a security multimedia card. Also, in the embodiment, the 'module' may include one or more processors. In the following description of the present disclosure, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted. Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0043] In the following description, terms for identifying connection nodes, terms for network entities, terms for messages, terms for interfaces between network entities, terms for various identification information, etc. are provided as examples for the convenience of description. Therefore, the present disclosure is not limited to the terms described below, and other terms for objects having equivalent technical meanings may be used.

[0044] Hereinafter, for convenience of explanation, the present disclosure uses terms and names defined in the 3GPP (registered trademark) LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present disclosure is not limited to the above terms and names, and may be similarly applied to systems according to other standards. In the present invention, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as eNB may indicate gNB.

[0045] Hereinafter, a base station is an entity that allocates resources to a terminal, and may be at least one of an eNode B, a Node B, a BS (Base Station), a radio access unit, a base station controller, or a node on a network. A 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. Of course, the above examples are not limited to the above examples.

[0046] In particular, the present disclosure may be applied to 3GPP (registered trademark) NR (5th generation mobile communication standard). In addition, the present disclosure may be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety related services, etc.) based on 5G communication technology and IoT related technology. In this disclosure, eNB may be used interchangeably with gNB for convenience of explanation. That is, the base station described as eNB may indicate gNB. In addition, the term terminal may refer to not only mobile phones, NB-IoT devices, and sensors but also other wireless communication devices.

[0047] Wireless communication systems have moved away from the voice-centric services provided in the early days and have evolved into broadband wireless communication systems providing high-speed, high-quality packet data services, such as communication standards such as 3GPP® High Speed ​​Packet Access (HSPA), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP®2 High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE (Institute of Electrical and Electronics Engineers) 802.16e.

[0048] As a representative example of a broadband wireless communication system, the LTE system adopts an Orthogonal Frequency Division Multiplexing (OFDM) scheme in the downlink (DL) and a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme in the uplink (UL). The uplink refers to a radio link through which a terminal (UE; User Equipment or MS; Mobile Station) transmits data or control signals to a base station (eNode B or BS; Base Station), and the downlink refers to a radio link through which a base station transmits data or control signals to a terminal. The multiple access scheme as described above divides the data or control information of each user by allocating and operating time-frequency resources for transmitting data or control information for each user so that they do not overlap with each other, i.e., so that orthogonality is established.

[0049] As a communication system after LTE, i.e., a 5G communication system, it is necessary to be able to freely reflect various requirements of users and service providers, etc., and therefore it is necessary to support services that simultaneously meet various requirements. Services considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (MTC), ultra-reliability low latency communication (URLLC), etc.

[0050] According to an embodiment, eMBB can aim to provide a data communication speed that is higher than the data communication speed supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB needs to be able to provide a peak data rate of 20 Gbps in the downlink and a peak data rate of 10 Gbps in the uplink from the viewpoint of one base station. In addition, the 5G communication system may need to provide an increased user perceived data rate while providing a peak data rate. In order to meet such requirements, the 5G communication system may require improvements in various transmission and reception technologies, including an improved multiple input multiple output (MIMO) transmission technology. In addition, the current LTE system transmits signals using a transmission bandwidth of up to 20 MHz (Megahertz) in the 2 GHz band, whereas the 5G communication system can meet the data communication speed required by the 5G communication system by using a frequency bandwidth wider than 20 MHz in the frequency band of 3 to 6 GHz or 6 GHz or higher.

[0051] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. In order to efficiently provide the Internet of Things, mMTC may be required to support large-scale terminal connection support within a cell, improve terminal coverage, improve battery time, reduce terminal costs, etc. The Internet of Things is installed in various sensors and various devices to provide communication functions, so it is necessary to support a large number of terminals (e.g., 1,000,000 terminals / km2) within a cell. In addition, because terminals supporting mMTC are likely to be located in shadow areas that cannot be covered by cells, such as underground areas of buildings, due to the nature of the service, wider coverage may be required compared to other services provided by 5G communication systems. Terminals supporting mMTC must be low-cost terminals, and since it is difficult to frequently replace the terminal battery, a very long battery life time such as 10 to 15 years may be required.

[0052] Finally, in the case of URLLC, as a mission-critical cellular-based wireless communication service, it may be used for services such as remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC may need to provide extremely low latency (ultra-low latency) and extremely high reliability (high reliability). For example, a service supporting URLLC may need to meet an air interface latency of less than 0.5 milliseconds and at the same time have a packet error rate requirement of 10-5 or less. Therefore, for a service supporting URLLC, the 5G system may need to provide a shorter transmission time interval (TTI) than other services, and at the same time, a design requirement may need to allocate wide resources in the frequency band to ensure the reliability of the communication link.

[0053] The three services considered in the above-mentioned 5G system, i.e., eMBB, URLLC, and mMTC, may be multiplexed and transmitted in one system. In this case, different transmission / reception techniques and transmission / reception parameters may be used between the services to meet different requirements of each service. However, the above-mentioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types to which the present disclosure is applicable are not limited to the above-mentioned examples.

[0054] In addition, the following describes an embodiment of the present disclosure using an LTE, LTE-A, LTE Pro, or 5G (or NR, next-generation mobile communication) system as an example, but the embodiment of the present disclosure may also be applied to other communication systems having a similar technical background or channel form. Furthermore, the embodiment of the present disclosure may also be applied to other communication systems with some modifications based on the judgment of a person skilled in the art without departing from the scope of the present disclosure.

[0055] FIG. 1A is a diagram illustrating a structure of an LTE system according to one embodiment of the present disclosure.

[0056] 1A, the radio access network of the LTE system is composed of next generation base stations (Evolved Node B, hereinafter referred to as eNB, Node B or base station) 1a-05, 1a-10, 1a-15, 1a-20, Mobility Management Entity (MME) 1a-25, and Serving-Gateway (S-GW) 1a-30. User equipment (User Equipment, hereinafter referred to as UE or terminal) 1a-35 connects to an external network via eNB 1a-05 to 1a-20 and S-GW 1a-30.

[0057] In FIG. 1A, eNBs 1a-05 to 1a-20 correspond to existing Node Bs in a Universal Mobile Telecommunication System (UMTS) system. The eNBs are connected to UEs 1a-35 via a radio channel and perform more complex roles than existing Node Bs. In the LTE system, all user traffic, including real-time services such as Voice over IP (VoIP) via Internet Protocol, is served via a shared channel, so that a device may be required to collect status information such as UE buffer status, available transmission power status, and channel status to perform scheduling, which is handled by eNBs 1a-05 to 1a-20. One eNB can usually control multiple cells. For example, to implement a transmission speed of 100 Mbps, the LTE system can use Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) with a 20 MHz bandwidth as a radio access technology. Of course, the above examples are not limited to the above examples. Moreover, the eNBs 1a-05 to 1a-20 can apply an Adaptive Modulation & Coding (AMC) method that determines a modulation scheme and a channel coding rate according to the channel state of the terminal. The S-GW (Serving Gateway) 1a-30 is a device that provides a data bearer, and generates or removes a data bearer under the control of the MME 1a-25. The MME (Mobility Management Entity) is a device that handles various control functions as well as mobility management functions for terminals, and is connected to multiple base stations.

[0058] FIG. 1B is a diagram illustrating a radio protocol structure in an LTE system according to one embodiment of the present disclosure.

[0059] Referring to FIG. 1B, the radio protocol of the LTE system may include Packet Data Convergence Protocol (PDCP) 1b-05, 1b-40, Radio Link Control (RLC) 1b-10, 1b-35, and Medium Access Control (MAC) 1b-15, 1b-30 in the terminal and eNB, respectively. Packet Data Convergence Protocol (PDCP) 1b-05, 1b-40 may be responsible for operations such as IP header compression / decompression. The main functions of PDCP are summarized as follows. Of course, the following examples are not limited to the above.

[0060] -Header compression and decompression function (ROHC (Robust Header compression) only) -Transfer of user data -In-sequence delivery of upper layer PDUs (protocol data unit) at PDCP re-establishment procedure for RLC AM -Reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception) -Duplicate detection of lower layer SDUs (service data unit) at PDCP re-establishment procedure for RLC AM -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) -Ciphering and deciphering function -Timer-based SDU discard in uplink

[0061] Radio Link Control (hereinafter referred to as RLC) 1b-10, 1b-35 can reconstruct PDCP PDU (Packet Data Unit) to an appropriate size and perform ARQ (automatic repeat request) operation. The main functions of RLC are summarized as follows. Of course, the following examples are not limited to these.

[0062] -Data transmission function (Transfer of upper layer PDUs) -ARQ function (Error Correction through ARQ (only for AM(Acknowledge Mode) data transfer)) -Concatenation, segmentation and reassembly of RLC SDUs (only for UM(Unacknowledged Mode) and AM data transfer) -Re-segmentation of RLC data PDUs (only for AM data transfer) -Reordering of RLC data PDUs (only for UM and AM data transfer) -Duplicate detection (only for UM and AM data transfer) -Error detection function (Protocol error detection (only for AM data transfer)) -RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer)) -RLC re-establishment function

[0063] The MAC 1b-15, 1b-30 is connected to several RLC layer devices configured in one terminal, and can perform operations of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of the MAC are summarized as follows. Of course, the following examples are not limited to the above.

[0064] -Mapping function (Mapping between logical channels and transport channels) -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 -Scheduling information reporting function -HARQ function (Error correction through HARQ) -Priority handling between logical channels of one UE -Priority handling between UEs by means of dynamic scheduling -MBMS service identification function -Transport format selection function -Padding function

[0065] The PHY layers 1d-20 and 1d-25 perform channel coding and modulation of higher layer data, generate OFDM symbols, and transmit them via a wireless channel, or demodulate and channel decode the OFDM symbols received via a wireless channel, and transmit them to a higher layer. Of course, the present invention is not limited to the above examples.

[0066] FIG. 1C is a diagram illustrating a structure of a next-generation mobile communication system according to one embodiment of the present disclosure.

[0067] 1C, as shown, a radio access network of a wireless communication system (hereinafter, next-generation mobile communication system, NR or 5G) may be configured with a next-generation base station (New Radio Node B, hereinafter, NR gNB or NR base station) 1c-10 and an NR CN (New Radio Core Network) 1c-05. A user terminal (New Radio User Equipment, hereinafter, NR UE or terminal) 1c-15 can connect to an external network via the NR gNB 1c-10 and the NR CN 1c-05.

[0068] In FIG. 1C, the NR gNB1c-10 can correspond to an eNB (Evolved Node B) of an existing LTE system. The NR gNB is connected to the NR UE1c-15 via a radio channel and can provide better services than existing Node Bs. In the next-generation mobile communication system, all user traffic is served via a shared channel, so a device may be required to collect status information such as the UE buffer status, available transmission power status, and channel status to perform scheduling, which the NR gNB1c-10 can handle. One NR gNB can usually control multiple cells.

[0069] According to an embodiment of the present disclosure, the next-generation mobile communication system may have a bandwidth larger than the existing maximum bandwidth to implement ultra-high-speed data transmission compared to LTE, and may use beamforming technology in addition to Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a wireless connection technology. Also, according to an embodiment of the present disclosure, the NR gNB1c-10 may apply an Adaptive Modulation & Coding (hereinafter referred to as AMC) scheme that determines a modulation scheme and a channel coding rate according to the channel state of the terminal. The NR CN1c-05 may perform functions such as mobility support, bearer setting, and Quality of Service (QoS) setting. The NR CN1c-05 is a device that is responsible for various control functions as well as a mobility management function for the terminal, and may be connected to multiple base stations. Also, the next-generation mobile communication system may be linked with the existing LTE system, and the NR CN may be connected to the MME1c-25 via a network interface. The MME can be connected to an existing base station, eNB1c-30.

[0070] FIG. 1D is a diagram illustrating a radio protocol structure of a next-generation mobile communication system according to one embodiment of the present disclosure.

[0071] Referring to FIG. 1D, the radio protocols of the next-generation mobile communication system may include NR SDAP (Service Data Adaption Protocol) 1d-01, 1d-45, NR PDCP (Packet Data Convergence Protocol) 1d-05, 1d-40, NR RLC (Radio Link Control) 1d-10, 1d-35, and NR MAC (Medium Access Control) 1d-15, 1d-30 in the terminal and NR base station, respectively.

[0072] According to an embodiment of the present disclosure, the main functions of the NR SDAP 1d-01, 1d-45 may include some of the following functions. Of course, the main functions are not limited to the following examples.

[0073] -Transfer of user plane data -Mapping function between a QoS flow and a data bearer for both uplink and downlink (mapping between a QoS flow and a DRB for both DL and UL) -Ability to mark QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets) - Reflective QoS flow to DRB mapping for the UL SDAP PDUs

[0074] For the SDAP layer device, the terminal can configure whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device for each PDCP layer device, or for each bearer, or for each logical channel in a Radio Resource Control (RRC) message. When the SDAP header is configured, the NAS QoS reflection setting 1-bit indicator (NAS reflective QoS) and the AS QoS reflection setting 1-bit indicator (AS reflective QoS) in the SDAP header can indicate that the terminal can update or reconfigure the mapping information for the uplink and downlink QoS flows and data bearers. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used for data processing priority, scheduling information, etc. to support smooth services.

[0075] According to an embodiment of the present disclosure, the main functions of the NR PDCP1d-05, 1d-40 may include some of the following functions. Of course, the main functions are not limited to the following examples.

[0076] -Header compression and decompression function (ROHC only) -Transfer of user data -In-sequence delivery of upper layer PDUs -Out-of-sequence delivery of upper layer PDUs -Reordering function (PDCP PDU reordering for reception) -Duplicate detection of lower layer SDUs -Retransmission of PDCP SDUs -Ciphering and deciphering function -Timer-based SDU discard in uplink

[0077] According to an embodiment of the present disclosure, the reordering function of the NR PDCP device may mean a function of reordering PDCP PDUs received at a lower layer in order based on a PDCP sequence number (SN). The reordering function of the NR PDCP device may include at least one of a function of delivering data to a higher layer in a reordered order, a function of delivering data immediately 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 a transmitting side, and a function of requesting retransmission of lost PDCP PDUs.

[0078] According to an embodiment of the present disclosure, the main functions of the NR RLC 1d-10, 1d-35 may include some of the following functions, but are not limited to the following examples.

[0079] -Data transmission function (Transfer of upper layer PDUs) -In-sequence delivery of upper layer PDUs -Out-of-sequence delivery of upper layer PDUs -ARQ function (Error Correction through ARQ) -Concatenation, segmentation and reassembly of RLC SDUs -Re-segmentation of RLC data PDUs -Reordering of RLC data PDUs -Duplicate detection -Protocol error detection -RLC SDU deletion function (RLC SDU discard) -RLC re-establishment function

[0080] According to one embodiment of the present disclosure, the in-sequence delivery function of the NR RLC device may refer to a function of delivering RLC SDUs received from a lower layer to a higher layer in order. The sequential delivery function may include at least one of the following functions: a function of reassembling and delivering an RLC SDU when one RLC SDU is split into several RLC SDUs and received; a function of reordering received RLC PDUs based on the RLC sequence number (SN) or PDCP sequence number (SN); a function of recording lost RLC PDUs by rearranging the sequence; a function of reporting the status of a lost RLC PDU to the transmitting side; a function of requesting retransmission of a lost RLC PDU; a function of delivering only RLC SDUs up to the lost RLC SDU in sequence to an upper layer in case of a lost RLC SDU; a function of delivering all RLC SDUs received before the timer started in sequence to an upper layer in case of a lost RLC SDU but a predetermined timer expires; or a function of delivering all RLC SDUs received up to now in sequence to an upper layer in case of a lost RLC SDU but a predetermined timer expires.

[0081] Also, according to an embodiment of the present disclosure, the NR RLC 1d-10, 1d-35 can process the RLC PDUs in the order in which they are received (in the order in which they arrive, regardless of the order of sequence numbers) and deliver them to the PDCP device out of sequence (out-of-sequence delivery), and in the case of a segment, the NR RLC 1d-10, 1d-35 can receive a segment stored in a buffer or received later, reconstruct it into one complete RLC PDU, and then process and deliver it to the PDCP device. The NR RLC 1d-10, 1d-35 may not include a concatenation function, and the concatenation function may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer. Of course, the above examples are not limited to the above examples.

[0082] The out-of-sequence delivery function of the NR RLC1d-10, 1d-35 device may include a function to immediately deliver RLC SDUs received from a lower layer to a higher layer regardless of the order, and may include at least one of the following functions: a function to reassemble and deliver an RLC SDU that was originally received divided into several RLC SDUs; and a function to store the RLC SN or PDCP SN of the received RLC PDU, sort the order, and record any lost RLC PDUs.

[0083] According to one embodiment of the present disclosure, the NR MACs 1d-15 and 1d-30 can be connected to several NR RLC layer devices configured in one terminal, and the main functions of the NR MAC can include some of the following functions. Of course, the following examples are not limited to these.

[0084] -Mapping function (Mapping between logical channels and transport channels) -Multiplexing / demultiplexing of MAC SDUs -Scheduling information reporting function -HARQ function (Error correction through HARQ) -Priority handling between logical channels of one UE -Priority handling between UEs by means of dynamic scheduling -MBMS service identification function -Transport format selection function -Padding function

[0085] According to an embodiment of the present disclosure, the NR PHY layers 1d-20 and 1d-25 may perform an operation of channel coding and modulating higher layer data, generating OFDM symbols, and transmitting the OFDM symbols over a wireless channel, or demodulating and channel decoding the OFDM symbols received over a wireless channel, and transmitting the same to a higher layer. Of course, the present disclosure is not limited to the above examples.

[0086] FIG. 1E is a flowchart illustrating a process in which a terminal in an RRC connected mode (RRC_CONNECTED) performs measurement based on measurement configuration information set by a base station according to an embodiment of the present disclosure.

[0087] Referring to FIG. 1E, the terminal 1e-01 may receive a predetermined RRC message (e.g., an RRC connection resumption message (RRCResume) or an RRC connection reconfiguration message (RRCReconfiguration) including measurement configuration information (measConfig) from the base station 1e-02 (step 1e-05). The measurement configuration information may refer to measurement configuration information that the terminal applies in the RRC connected mode (RRC_CONNECTED). The measurement configuration information may include measurement gap configuration information (MeasGapConfig). The MeasGapConfig may also configure gap configuration information (GapConfig) for each FR (for example, gapFR1 or gapFR2) and may configure terminal gap configuration information (gapUE). The MeasGapConfig may include at least one of the following parameters, and the definition of each parameter is as follows:

[0088] [Table 1]

[0089] [Table 2A]

[0090] [Table 2B]

[0091] MeasGapConfig may have the following characteristics, but is not limited to the following exemplary characteristics:

[0092] The base station 1e-02 can determine whether to set up or release GapConfig as measurement gap configuration information that the base station 1e-02 sets for the terminal 1e-01. In other words, the terminal cannot request the base station to set up or release GapConfig.

[0093] When the base station 1e-02 configures the terminal gap (gapUE) for the terminal 1e-01, each parameter included in GapConfig cannot be configured more than once, i.e., only one value can be configured for gapOffset, mgl, mgta, etc. in GapConfig.

[0094] When the base station 1e-02 configures a GapConfig for each FR1 gap (gapFR1) and / or FR2 gap (gapFR2) in the terminal 1e-01, each parameter included in each GapConfig cannot be configured more than once. That is, only one value can be configured for each GapConfig, such as gapOffset, mgl, and mgta.

[0095] In step 1e-10, the terminal 1e-01 in the RRC connected mode can perform measurements by applying the measurement gap configuration information. The time to perform measurements can be determined as follows.

[0096] -if gapFR1 is set to setup:

[0097] If an FR1 measurement gap configuration is already setup, release the FR1 measurement gap configuration;

[0098] In step 1e-10, the FR1 measurement gap configuration indicated by the measGapConfig in accordance with the received gapOffset, i.e., the first subframe of each gap occurs at an SFN and subframe meeting the following condition 1.

[0099] <Condition 1> SFN mod T = FLOOR(gapOffset / 10); subframe = gapOffset mod 10; with T = MGRP / 10 as defined in TS 38.133;

[0100] ○The UE can apply mgta (measurement gap timing advance) to gaps that occur when condition 1 is satisfied. That is, the UE can apply the timing advance specified by mgta to the time point of gaps that occur when condition 1 is satisfied. For example, the UE can start measurement by mgta earlier than the time point of gap subframe occurrence (apply the specified timing advance mgta to the gap occurrences calculated above (ie the UE starts the measurement mgta ms before the gap subframe occurrences));

[0101] -else if gapFR1 is set to release:

[0102] ○Can release the FR1 measurement gap configuration;

[0103] -if gapFR2 is set to setup:

[0104] If an FR2 measurement gap configuration is already setup, release the FR2 measurement gap configuration;

[0105] 〇Set up the FR2 measurement gap configuration indicated by the measGapConfig received in step 1e-10 taking into account the gapOffset information. Specifically, the first subframe of each gap occurs at an SFN (System Frame Number) and subframe meeting the above condition 1.

[0106] ○ The UE can apply mgta to gaps that occur when condition 1 is satisfied. That is, the UE can apply the timing advance specified by mgta to the time point of gaps that occur when condition 1 is satisfied. For example, the UE can start measurements by mgta earlier than the time point of gap subframe occurrence (apply the specified timing advance mgta to the gap occurrences calculated above (ie the UE starts the measurement mgta ms before the gap subframe occurrences));

[0107] -else if gapFR2 is set to release:

[0108] ○ Release the FR2 measurement gap configuration;

[0109] -if gapUE is set to setup:

[0110] If a per UE measurement gap configuration is already setup, release the per UE measurement gap configuration;

[0111] 〇The per UE measurement gap configuration indicated by the measGapConfig received in step 1e-10 can be set up taking into account the gapOffset information. Specifically, the first subframe in which each gap occurs occurs at an SFN (System Frame Number) and subframe meeting the above condition 1.

[0112] ○ The UE can apply mgta to gaps that occur when condition 1 is satisfied. That is, the UE can apply the timing advance specified by mgta to the time point of gaps that occur when condition 1 is satisfied. For example, the UE can start measurements by mgta earlier than the time point of gap subframe occurrence (apply the specified timing advance mgta to the gap occurrences calculated above (ie the UE starts the measurement mgta ms before the gap subframe occurrences));

[0113] -else if gapUE is set to release:

[0114] ○ Release the per UE measurement gap configuration;

[0115] FIG. 1F is a diagram illustrating an embodiment of the present disclosure in which a terminal (Multi-USIM UE) supporting multiple Universal Subscriber Identity Modules (USIMs) performs an operation associated with another USIM while maintaining an RRC connected mode (RRC_CONNECTED) with a base station associated with one USIM.

[0116] A Multi-USIM terminal 1f-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. In the present disclosure, for convenience of explanation, an embodiment will be described based on a Dual-USIM terminal supporting two USIMs. A Dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, a Dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or simultaneously receive data or information from base stations associated with each USIM.

[0117] Referring to FIG. 1F, the multi-USIM terminal 1f-01 may refer to a terminal that supports multiple USIMs. As an example, the multi-USIM terminal may refer to the first USIM terminal 1f-02 when operating in USIM 1, and may refer to the second USIM terminal 1f-03 when operating in USIM 2. A base station associated with each USIM may recognize the multi-USIM terminal not as one terminal, but each USIM separately. As an example, the first base station 1f-04 may recognize the first USIM terminal 1f-02 as one terminal, and the second base station 1f-05 may recognize the second USIM terminal 1f-03 as one terminal. Hereinafter, for convenience of explanation, in the embodiment of the present disclosure, when the multi-USIM terminal 1f-01 communicates using USIM 1, the multi-USIM terminal 1f-01 will be referred to as the first USIM terminal 1f-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal communicates using USIM 2, the multi-USIM terminal will be referred to as the second USIM terminal 1f-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal 1f-01 can be the first USIM terminal 1f-02 or the second USIM terminal 1f-03 depending on whether the multi-USIM terminal 1f-01 uses USIM 1 or USIM 2.

[0118] In step 1f-10, the first USIM terminal 1f-02 may establish an RRC connection with the first base station 1f-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1f-10, the second USIM terminal 1f-03 may not establish an RRC connection with the second base station 1f-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0119] In step 1f-15, the first USIM terminal 1f-02 may transmit a UE Capability Information message (UECapabilityInformation) to the first base station 1f-04. The UE Capability Information message may include at least one of the following information, but is not limited to the following examples:

[0120] -An indicator or information element that the first USIM terminal 1f-02 supports a procedure for switching from the RRC connected mode from the first base station 1f-04 to the second USIM terminal 1f-03 (support of switching procedure for leaving RRC_CONNECTED state for Multi-USIM purpose) may be included. As an example, when the second USIM terminal 1f-03 needs to establish or resume an RRC connection with the second base station 1f-05 and transition to the RRC connected mode, the first USIM terminal 1f-02 may perform a procedure (i.e., switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1f-04 of a desire to leave the RRC connected mode or to inform the RRC state to which it is to transition (e.g., RRC idle mode or RRC inactive mode).

[0121] -An indicator or information element indicating that the first USIM terminal 1f-02 supports a procedure for switching to the second USIM terminal 1f-03 while maintaining the RRC connected mode with the first base station 1f-04 (support of switching procedure without leaving RRC_CONNECTED state) may be included. As an example, a procedure for the second USIM terminal 1f-03 to perform an operation associated with the second base station 1f-05 while the first USIM terminal 1f-02 maintains the RRC connected mode with the first base station 1f-04 may be referred to as a switching procedure without leaving RRC_CONNECTED state, and an indicator or information element indicating that the first USIM terminal 1f-02 supports switching gaps required for switching to the second USIM terminal 1f-03 and communicating with the second base station 1f-05 while maintaining the RRC connected mode with the first base station 1f-04 (support of switching gaps for Multi-USIM purpose) may be included.

[0122] The switching gap may include a per UE level switching gap. If the first USIM terminal 1f-02 supports a per FR or per frequency switching gap, a separate indicator or information element indicating information regarding support for a per FR or per frequency switching gap may be included in the terminal capability information message.

[0123] In step 1f-20, the first base station 1f-04 may transmit a predetermined RRC message (e.g., an RRCReconfiguration message, an RRCResume message, or a new RRC message) including configuration information (SwitchingGapReportingConfig) that allows the first USIM terminal 1f-02 to report switching gap information preferred / required for Multi-USIM operation. Additionally, the SwitchingGapReportingConfig may be stored in otherConfig. The SwitchingGapReportingConfig may be configuration information associated with a switching procedure without leaving RRC_CONNECTED state. The SwitchingGapReportingConfig may include at least one of the following:

[0124] -An indicator or information element (for example, SetupRelease) that sets whether the first base station 1f-04 may transmit switching gap setting information that the second USIM terminal 1f-03 prefers to perform an operation associated with the second base station 1f-05 while the first USIM terminal 1f-02 maintains the RRC connection mode with the first base station 1f-04.

[0125] -New prohibit timer value

[0126] --If the first base station 1f-04 sets or sets up a new prohibit timer value in the first USIM terminal 1f-02, when the first USIM terminal 1f-02 starts a procedure for sending preferred switching gap setting information to the first base station 1f-04, it can start a new timer with the new prohibit timer value and transmit a predetermined RRC message including the preferred switching gap setting information to the first base station 1f-04. If the new prohibit timer is running, the first USIM terminal 1f-02 may not be able to transmit a predetermined RRC message including the switching gap setting information preferred by the first USIM terminal 1f-02 to the first base station 1f-04. That is, if the new prohibit timer is not running or has expired, the first USIM terminal 1f-02 can transmit a predetermined RRC message including the switching gap setting information preferred by the first USIM terminal 1f-02 to the first base station 1f-04.

[0127] In step 1f-25, the second USIM terminal 1f-03 can determine whether to perform a predetermined operation in the RRC idle mode or the RRC inactive mode. The predetermined operation is an operation in which the second USIM terminal 1f-03 is associated with the second base station 1f-05, and can mean at least one of the following. Of course, the following examples are not limited to these.

[0128] - Operation 1: The second USIM terminal 1f-03 does not perform an RRC connection establishment procedure or an RRC connection resume procedure with the second base station 1f-05, but performs an operation of receiving a signal transmitted by the second base station 1f-05 or an internal operation of the second USIM terminal by receiving the signal. As an example,

[0129] The second USIM terminal 1f-03 may perform paging channel or short message monitoring associated with the second base station 1f-05. As an example, the second USIM terminal 1f-03 may monitor a paging occasion every DRX (Discontinuous Reception) cycle.

[0130] The second USIM terminal 1f-03 may monitor to receive a system information change notification associated with the second base station 1f-05. As an example, the second USIM terminal 1f-03 may monitor a paging occasion for each Discontinuous Reception (DRX) cycle.

[0131] The second USIM terminal 1f-03 may perform a cell selection or cell reselection evaluation procedure. As an example, the second USIM terminal may perform serving cell or neighboring cell measurements as part of the cell selection or cell reselection evaluation procedure.

[0132] --The second USIM terminal 1f-03 can perform a PLMN (Public Land Mobile Network) selection procedure.

[0133] - Operation 2: The second USIM terminal 1f-03 does not perform an RRC connection establishment procedure or an RRC connection resume procedure with the second base station 1f-05, but performs transmission and reception with the second base station 1f-05. As an example,

[0134] The second USIM terminal 1f-03 requests on-demand system information from the second base station 1f-05 to acquire system information in an on-demand manner.

[0135] - Operation 3: The second USIM terminal 1f-03 in the RRC inactive mode performs an RRC connection resumption procedure with the second base station 1f-05, but cannot transition to the RRC connected mode. As an example,

[0136] --The second USIM terminal 1f-03 receives a RAN paging message transmitted by the second base station 1f-05, and the received RAN paging message includes a UE identifier (I-RNTI) indicating the second USIM terminal 1f-03. However, if the first USIM terminal 1f-02 needs to continuously transmit and receive data with the first base station 1f-04, the second USIM terminal 1f-03 can transmit to the second base station 1f-05 an RRCResumeRequest / 1 message that stores a busy indication indicating that the second USIM terminal 1f-03 cannot respond to the RAN paging message received from the second base station 1f-05. According to an embodiment of the present disclosure, the busy indication can be stored in resumeCause. In response to the RAN paging message, the second base station 1f-05 can transmit an RRCReject or RRCRelease message to the second USIM terminal 1f-03.

[0137] -Operation 4: The second USIM terminal 1f-03 performs an RRC connection establishment or resumption procedure with the second base station 1f-05 to transition to the RRC connection mode. As an example,

[0138] --The second USIM terminal 1f-03 can perform a Registration Update procedure or a RAN Notification Area Update procedure.

[0139] The above operations may refer to periodic operations, or non-periodic operations, or one-time operations.

[0140] In step 1f-30, the second USIM terminal 1f-03 may inform the first USIM terminal 1f-02 of information required to perform the operation described above in step 1f-25 in the RRC idle mode or the RRC inactive mode. For reference, step 1f-30 may be an operation performed inside the multi-USIM terminal 1f-01. That is, step 1f-30 is a step that does not require separate communication with a base station and is implemented only inside the multi-USIM terminal 1f-01, and may be a step that means data processing inside the multi-USIM terminal 1f-01 and is not a required step.

[0141] In step 1f-35, the first USIM terminal 1f-02 may transmit a predetermined RRC message (e.g., a UE Assistance Information message or a new RRC message) storing configuration information (SwitchingGapConfigPreference) for one or more preferred switching gap patterns to the first base station 1f-04. The SwitchingGapConfigPreference may mean configuration information different from the measurement configuration information (MeasConfig) of the above-mentioned embodiment. Specifically,

[0142] -SwitchingGapConfigPreference is switching gap setting information transmitted and requested by the first USIM terminal 1f-02 to the first base station 1f-04 in order for the second USIM terminal 1f-03 to perform the predetermined operation described above in step 1f-30. That is, it is setting information for one or more switching gap patterns preferred by the first USIM terminal 1f-02 to the first base station 1f-04 for Multi-USIM operation. In the present disclosure, the switching gap(pattern) may be referred to as MUSIM gap(pattern).

[0143] -SwitchingGapConfigPreference may include one or more switching gap pattern information preferred by the first USIM terminal 1f-02 according to the operation required in step 1f-25. That is, one or more switching gap pattern information preferred by each first USIM terminal 1f-02 may be included in SwitchingGapConfigPreference. As an example, a list in which one or more MUSIM-GapInfo-r17 are stored may be included in SwitchingGapConfigPreference.

[0144] -Each switching gap pattern information may be periodic switching gap pattern information or one-shot / aperiodic switching gap pattern information. In the present disclosure, it is proposed that the first USIM terminal 1f-02 includes a switching gap repetition period (switching gap repetition period value, musim-GapRepetitionPeriod) when it prefers periodic switching gap pattern information, and includes musim-GapStartSFN (SFN value at which the switching gap starts) when it prefers aperiodic / one shot switching gap pattern information. The reason why the first USIM terminal 1f-02 includes musim-GapStartSFN in the aperiodic / one shot switching gap pattern information is that the SFN value cannot be derived without the switching gap repetition period value in the formula of the condition 1 of the above embodiment. And, at least one of the following parameters may be included in common for the periodic switching gap pattern and the aperiodic / one shot switching gap pattern.

[0145] --switching gap length(musim-GapLength): A value (ms) indicating the length of the switching gap (musim gap) preferred by the first USIM terminal 1f-02

[0146] --switching gap offset (musim-Gap offset): A value indicating the gap offset of the switching gap (musim gap) preferred by the first USIM terminal 1f-02

[0147] --switching gap timing advance: value (ms) indicating the timing advance (musim gap timing advance) of the switching gap preferred by the first USIM terminal 1f-02

[0148] --refServCellIndicator: a value indicating a serving cell. Used by the first USIM terminal 1f-02 to calculate a gap of a switching gap pattern via the SFN and subframe of the serving cell, it can indicate one of a PCell, a PSCell, and an SCell. Of course, if there is no refServCellIndicator or the refServCellIndicator field itself is not defined, the first USIM terminal 1f-02 can always calculate the gap of a switching gap pattern via the SFN and subframe of the PCell.

[0149] As an example, each switching gap pattern information may have an ASN.1 structure as follows:

[0150] MUSIM-GapInfo-r17 ::= SEQUENCE { musim-GapOffset-r17 ENUMERATED {FFS}, musim-GapLength-r17 ENUMERATED {FFS}, musim-GapType-r17 CHOICE { musim-GapRepetitionPeriod-r17 ENUMERATED {FFS} musim-GapStartSFN-r17 ENUMERATED {FFS} }

[0151] With regard to the periodic switching gap pattern information, the first subframe in which each switching gap (musim gap) occurs based on the PCell or based on the cell indicated by the refServCellIndicator in the first USIM terminal 1f-02 may mean a SFN (System Frame Number) and subframe that satisfy the following condition 1 (the first subframe of each MUSIM gap occurs at an SFN and subframe meeting the below condition 1).

[0152] <Condition 1> SFN mod T = FLOOR(musim-GapOffset / 10); subframe = musim-gapOffset mod 10; with T = musim-GapRepetitionPeriod / 10 as defined in TS 38.133;

[0153] The switching gap timing advance can be applied to gaps that occur when condition 1 is satisfied. That is, the terminal can apply the timing advance indicated by the switching gap timing advance to the gap time point that occurs when condition 1 is satisfied. For example, the terminal can start measurement earlier than the gap subframe occurrence time by the switching gap timing advance (apply the specified timing advance switching gap timing advance to the gap occurrences calculated above). For reference, the constant 10 in condition 1 is just an example, and other constant values ​​such as 2, 5, 100, etc. may also be used.

[0154] With regard to the aperiodic / one-shot switching gap pattern information, the first subframe in which each switching gap (MUSIM gap) occurs based on the PCell or based on the cell indicated by the refServCellIndicator in the first USIM terminal 1f-02 may mean an SFN and subframe that satisfy the following condition 2 (the first subframe of each MUSIM gap occurs at an SFN and subframe meeting the below condition 2).

[0155] <Condition 2> SFN = musim-GapStartSFN (SFN value where the switching gap starts) subframe = musim-GapOffset mod 10;

[0156] The switching gap timing advance can be applied to gaps that occur when condition 2 is satisfied. That is, the terminal can apply the timing advance indicated by the switching gap timing advance to the gap time point that occurs when condition 2 is satisfied. For example, the terminal can start measurement m switching gap timing advance earlier than the gap subframe occurrence time point (apply the specified timing advance switching gap timing advance to the gap occurrences calculated above). For reference, the constant 10 in condition 2 is just an example, and other constant values ​​such as 2, 5, 100, etc. may also be used.

[0157] Alternatively, the first USIM terminal 1f-02 may include a value of the actual starting subframe instead of the USIM-GapOffset in the aperiodic / one-shot switching gap pattern information. In this case, condition 2 may be expressed as follows.

[0158] <Condition 2-1> SFN = musim-GapStartSFN (SFN value where the switching gap starts) subframe = musim-GapStartsubframe;

[0159] In step 1f-35, the first USIM terminal 1f-02 may transmit a predetermined RRC message including SwitchingGapConfigPreference to the first base station 1f-04 if at least one of the following conditions is met:

[0160] -Condition 1: After the SwitchingGapReportingConfig is set in step 1f-20, a predetermined RRC message including SwitchingGapConfigPreference is not transmitted and at least one new MUSIM gap is required. In this case, the new MUSIM gap may include both periodic musim gap and aperiodic / one-shot musim gap.

[0161] -Condition 2: When the currently preferred SwitchingGapConfigPreference is different from the most recently sent SwitchingGapConfigPreference. In this case, the first USIM terminal 1f-02 can determine whether or not condition 2 is satisfied by considering only the periodic MUSIM gap. Of course, the first USIM terminal 1f-02 can also determine whether or not condition 2 is satisfied by considering both the periodic MUSIM gap and the aperiodic / one-shot MUSIM gap. The reason why the first USIM terminal 1f-02 determines whether or not condition 2 is satisfied by considering only the periodic MUSIM gap is that the aperiodic / one-shot MUSIM gap is, as the name suggests, a MUSIM gap that is not used after it is used once (both the first USIM terminal 1f-02 and the first base station 1f-04 know this), and therefore the first USIM terminal 1f-02 has the advantage of not having to unnecessarily transmit UEAssistanceInformation to the first base station 1f-04 requesting the release of the aperiodic / one-shot MUSIM gap. Additionally, the first USIM terminal 1f-02 can determine whether or not condition 2 is satisfied only when the new prohibit timer is not running. Also, when condition 2 is satisfied, the first USIM terminal 1f-02 can not include unnecessary MUSIM gaps among the MUSIM gaps set by the first base station 1f-04 in the SwitchingGapConfigPreference. That is, the first USIM terminal 1f-02 can implicitly inform the first base station 1f-04 of MUSIM gaps that are no longer necessary.

[0162] For reference, in step 1f-35, if a new prohibit timer value is set in step 1f-20, the first USIM terminal 1f-02 can start or restart a new timer with the corresponding value and transmit a specified RRC message including SwitchingGapConfigPreference to the first base station 1f-04.

[0163] In step 1f-40, the first base station 1f-04 may transmit a predetermined RRC message (for example, RRCReconfiguration, RRCResume, or new RRC message) in which one or more switching gap setting information (SwitchingGapConfig or MUSIMGapConfig) is stored based on the SwitchingGapConfigPreference requested by the first USIM terminal 1f-02 as a response to step 1f-35. Specifically, the first base station 1f-04 may transmit a predetermined RRC message including MUSIMGapConfig to the first USIM terminal 1f-02 based on the SwitchingGapConfigPreference received in step 1f-35. In the present disclosure, the first base station 1f-04 may set MUSIMGapConfig to the first USIM terminal 1f-02 through at least one of the following methods.

[0164] Method 1: MUSIM-GapId list to indicate setting to actual MUSIM gap

[0165] -MUSIM-GapId=1 may mean the first MUSIM Gap included in the SwitchingGapConfigPreference, MUSIM-GapId=2 may mean the second MUSIM Gap included in the SwitchingGapConfigPreference, and MUSIM-GapId=3 may mean the third MUSIM Gap included in the SwitchingGapConfigPreference. Therefore, when MUSIM-GapId=1 and MUSIM-GapId=3 are included in MUSIMGapConfig, the first base station 1f-04 may instruct the first USIM terminal 1f-02 to set the first MUSIM Gap and the third MUSIM Gap included in the SwitchingGapConfigPreference. In other words, the second MUSIM Gap included in the SwitchingGapConfigPreference may mean that the first USIM terminal 1f-02 cannot use it.

[0166] For example, a MUSIMGapConfig from method 1 may have the following ASN.1 structure:

[0167] MUSIM-GapConfig-r17 ::= SEQUENCE { musim-GapUE-r17 SEQUENCE (SIZE (1..FFS)) OF MUSIM-GapId OPTIONAL -- Need R }

[0168] Method 2: Includes the actual MUSIM Gap setting information and the MUSIM-GapId mapped to it via ToAddMostList and ToReleaseList

[0169] The first base station 1f-04 may include the setting information for each MUSIM gap and the MUSIM-GapId mapped thereto in the MUSIMGapConfig based on the SwitchingGapConfigPreference received in step 1f-35 as follows: In this case, each MUSIM-Gap included in the MUSIMGapConfig may actually be set to a value different from the preferred MUSIM-Gap included in the SwitchingGapConfigPreference.

[0170] For example, a MUSIMGapConfig from method 2 may have the following ASN.1 structure:

[0171] MUSIM-GapConfig-r17 ::= SEQUENCE { musim-GapUEToAddModList-r17 SEQUENCE (SIZE (1..FFS)) OF MUSIM-Gap OPTIONAL, -- Need N musim-GapUEToReleaseList-r17 SEQUENCE (SIZE (1..FFS)) OF MUSIM-GapId OPTIONAL -- Need N } MUSIM-Gap ::= SEQUENCE { musim-GapId MUSIM-GapId, musim-GapOffset-r17 ENUMERATED {FFS}, musim-GapLength-r17 ENUMERATED {FFS}, musim-GapType-r17 CHOICE { musim-GapRepetitionPeriod-r17 ENUMERATED {FFS} musim-GapStartSFN-r17 ENUMERATED {FFS} } ...

[0172] In step 1f-45, the first USIM terminal 1f-02 may transmit a predetermined RRC message to the first base station 1f-04 in response to the predetermined RRC message received in step 1f-40. As an example, the predetermined RRC message may be an RRCReconfigurationComplete, an RRCResumeComplete, or a new RRC message.

[0173] In step 1f-50, the first USIM terminal 1f-02 may determine whether one or more switching gaps have occurred through the SwitchingGapConfig received and applied in step 1f-40. For example,

[0174] -If SwitchingGapConfig is set to Setup:

[0175] If SwitchingGapConfig has already been set up, you can remove the already set up SwitchingGapConfig;

[0176] o One or more switching gap patterns may be set up as indicated by the SwitchingGapConfig received in step 1f-40. Specifically, if each switching gap is a periodic MUSIM gap, the first subframe in which the gap occurs may be an SFN and subframe that satisfy the above-mentioned condition 1. If each switching gap is an aperiodic / one-shot MUSIM gap, the first subframe in which the gap occurs may be an SFN and subframe that satisfy the above-mentioned condition 2.

[0177] ○ The switching gap timing advance set for each switching gap that occurs when condition 1 or condition 2 is satisfied can be applied.

[0178] The second USIM terminal 1f-03 can perform a predetermined operation only for the switching length set in each switching gap from the occurrence of the gap surf frame.

[0179] - if SwitchingGapConfig is set to clear, it can clear one or more gap patterns cleared in SwitchingGapConfig;

[0180] When a switching gap occurs in step 1f-50, the second USIM terminal 1f-03 can perform at least one of the operations of step 1f-25 described above for a switching gap length from the time when the switching gap occurs in step 1f-50. In this case, the first USIM terminal 1f-02 can maintain the RRC connection mode with the first base station 1f-04.

[0181] FIG. 1G is a diagram illustrating an embodiment of the present disclosure in which a terminal (Multi-USIM UE) supporting multiple Universal Subscriber Identity Modules (USIMs) releases an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performs an operation associated with another USIM.

[0182] A Multi-USIM terminal 1g-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. For convenience of explanation, the present disclosure will describe the embodiment based on a Dual-USIM terminal supporting two USIMs. A Dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, a Dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or simultaneously receive data or information from base stations associated with each USIM.

[0183] Referring to FIG. 1G, the multi-USIM terminal 1g-01 may refer to a terminal that supports multiple USIMs. For example, the multi-USIM terminal may refer to the first USIM terminal 1g-02 when operating in USIM 1, and may refer to the second USIM terminal 1g-03 when operating in USIM 2. A base station associated with each USIM may recognize the multi-USIM terminal not as a single terminal, but as each USIM. For example, the first base station 1g-04 may recognize the first USIM terminal 1g-02 as a single terminal, and the second base station 1g-05 may recognize the second USIM terminal 1g-03 as a single terminal. Hereinafter, for convenience of explanation, in the embodiment of the present disclosure, when a multi-USIM terminal communicates using USIM 1, the multi-USIM terminal 1g-01 will be referred to as a first USIM terminal 1g-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal communicates using USIM 2, the multi-USIM terminal 1g-01 will be referred to as a second USIM terminal 1g-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal 1g-01 can be the first USIM terminal 1g-02 or the second USIM terminal 1g-03 depending on whether the multi-USIM terminal 1g-01 uses USIM 1 or USIM 2.

[0184] In step 1g-10, the first USIM terminal 1g-02 may establish an RRC connection with the first base station 1g-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1g-10, the second USIM terminal 1g-03 may not establish an RRC connection with the second base station 1g-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0185] In step 1g-15, the first USIM terminal 1g-02 may transmit a terminal capability information message (UECapabilityInformation) to the first base station 1g-04. The terminal capability information message may include at least one of the following information, which is of course not limited to the following examples:

[0186] -An indicator or information element that the first USIM terminal 1g-02 supports a procedure for switching from the first base station 1g-04 to the second USIM terminal 1g-03 away from the RRC connected mode may be included. As an example, when the second USIM terminal 1g-03 establishes or resumes an RRC connection with the second base station 1g-05 and transitions to the RRC connected mode, the first USIM terminal 1g-02 may perform a procedure (i.e., a switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1g-04 of a desire to leave the RRC connected mode or to inform the first base station 1g-04 of a preferred RRC state (e.g., RRC idle mode, RRC inactive mode, or RRC connected mode).

[0187] In step 1g-20, the first base station 1g-04 may configure the first USIM terminal 1g-02 to perform a switching procedure for leaving RRC_CONNECTED state. As an example, the first base station 1g-04 may configure the first USIM terminal 1g-02 to perform a switching procedure for leaving RRC_CONNECTED state via an RRCReconfiguration message in which otherConfig is stored. Additionally, the first base station 1g-04 may include a new timer musim-LeaveWithoutResponseTimer value in otherConfig. The musim-LeaveWithoutResponseTimer value is for enabling the first USIM terminal 1g-02 to autonomously transition to the RRC_IDLE state without a response from the base station, and a specific terminal operation may be as follows.

[0188] -If the first USIM terminal 1g-02 is configured to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1g-04 and needs to leave the RRC_CONNECTED state (if USIM 1 UE is configured to perform MUSIM assistance information or switching procedure for leaving RRC_CONNECTED state and if the USIM 1 UE needs to leave RRC_CONNECTED state), the first USIM terminal 1g-02 can initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1g-04. To this end, when the first USIM terminal 1g-02 initiates the UEAssistanceInformation procedure, it can start a T3xx timer with a musim-LeaveWithoutResponseTimer value set by the first base station 1g-04. When the first USIM terminal 1g-02 receives a predetermined RRC message (e.g., RRCRelease) from the first base station 1g-04, it can stop the running T3xx timer. If the first USIM terminal 1g-02 does not receive a predetermined RRC message from the first base station 1g-04 and the running T3xx timer expires, it can automatically transition to the RRC_IDLE state.

[0189] In step 1g-25, the second USIM terminal 1g-03 may inform the first USIM terminal 1g-02 to establish or re-establish an RRC connection with the second base station 1g-05.

[0190] In step 1g-30, the first USIM terminal 1g-02, which is configured to be able to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1g-04, can determine whether or not the following condition A is satisfied.

[0191] -Condition A: If the USIM 1 UE needs to leave RRC_CONNECTED state due to Multi-USIM operation

[0192] In step 1g-35, if condition A is satisfied, the first USIM terminal 1g-02 may initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state. Then, the first USIM terminal 1g-02 may start a T3xx timer with a musim-LeaveWithoutResponseTimer value if the musim-LeaveWithoutResponseTimer value is set from the first base station 1g-04. Then, the first USIM terminal 1g-02 may transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1g-04. The musim-PreferredRRC-State may represent at least one value of IDLE, INACTIVE, and OutOfConnected. IDLE may indicate a preference that the first USIM terminal 1g-02 wishes to transition to RRC_IDLE, INACTIVE may indicate a preference that the first USIM terminal 1g-02 wishes to transition to RRC_INACTIVE, and OutOfConnected may indicate a preference that the first USIM terminal 1g-02 wishes to move away from RRC_CONNECTED without preferring to transition to RRC_IDLE or RRC_INACTIVE.

[0193] In step 1g-40, the first USIM terminal 1g-02 in the RRC connected mode (e.g., it may be in the RRC connected mode without receiving a specified RRC message (e.g., RRCRelease) from the first base station 1g-04) is configured to be able to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1g-04, and can determine whether the following condition A is satisfied.

[0194] -Condition A: If the USIM 1 UE needs to leave RRC_CONNECTED state due to Multi-USIM operation

[0195] In step 1g-45, if condition A is satisfied, the first USIM terminal 1g-02 may initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state, i.e., the first USIM terminal 1g-02 may perform step 1g-45 according to step 1g-35.

[0196] In the present disclosure, the first USIM terminal 1g-02, which is configured to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1g-04, may successfully transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1g-04, but may remain in the RRC connected mode without receiving a predetermined RRC message (e.g., RRCRelease) from the first base station 1g-04. However, when wanting to leave the RRC connected mode due to Multi-USIM operation, the first USIM terminal 1g-02 may unnecessarily continuously transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1g-04.

[0197] FIG. 1H is a diagram illustrating a terminal (Multi-USIM UE) supporting multiple Universal Subscriber Identity Modules (USIMs) releasing an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performing an operation associated with another USIM, according to one embodiment of the present disclosure.

[0198] A multi-USIM terminal 1h-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. For convenience of explanation, the present disclosure will describe the embodiment based on a dual-USIM terminal supporting two USIMs. A dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, a dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or simultaneously receive data or information from base stations associated with each USIM.

[0199] Referring to FIG. 1H, the multi-USIM terminal 1h-01 may refer to a terminal that supports multiple USIMs. For example, the multi-USIM terminal may refer to the first USIM terminal 1h-02 when operating in USIM 1, and may refer to the second USIM terminal 1h-03 when operating in USIM 2. A base station associated with each USIM may recognize the multi-USIM terminal 1h-01 not as one terminal, but each USIM separately. For example, the first base station 1h-04 may recognize the first USIM terminal 1h-02 as one terminal, and the second base station 1h-05 may recognize the second USIM terminal 1h-03 as one terminal. Hereinafter, in the embodiment of the present disclosure, for convenience of explanation, when the multi-USIM terminal 1h-01 communicates using USIM 1, the multi-USIM terminal 1h-01 will be referred to as a first USIM terminal 1h-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal 1h-01 communicates using USIM 2, the multi-USIM terminal will be referred to as a second USIM terminal 1h-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal can be the first USIM terminal 1h-02 or the second USIM terminal 1h-03 depending on which USIM, USIM 1 or USIM 2, is used.

[0200] In step 1h-10, the first USIM terminal 1h-02 may establish an RRC connection with the first base station 1h-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1h-10, the second USIM terminal 1h-03 may not establish an RRC connection with the second base station 1h-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0201] In step 1h-15, the first USIM terminal 1h-02 may transmit a terminal capability information message (UECapabilityInformation) to the first base station 1h-04. The terminal capability information message may include at least one of the following information, which is of course not limited to the following examples:

[0202] -An indicator or information element that the first USIM terminal 1h-02 supports a procedure for switching from the first base station 1h-04 to the second USIM terminal 1h-03 away from the RRC connected mode may be included. As an example, when the second USIM terminal 1h-03 establishes or resumes an RRC connection with the second base station 1h-05 and transitions to the RRC connected mode, the first USIM terminal 1h-02 may perform a procedure (i.e., a switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1h-04 of a desire to leave the RRC connected mode or to inform the first base station 1h-04 of a preferred RRC state (e.g., RRC idle mode, RRC inactive mode, or RRC connected mode).

[0203] In step 1h-20, the first base station 1h-04 may configure the first USIM terminal 1h-02 to perform a switching procedure for leaving RRC_CONNECTED state. As an example, the first base station 1h-04 may configure the first USIM terminal 1h-02 to perform a switching procedure for leaving RRC_CONNECTED state via an RRCReconfiguration message in which otherConfig is stored. Additionally, the first base station 1h-04 may include a new timer musim-LeaveWithoutResponseTimer value in otherConfig. The musim-LeaveWithoutResponseTimer value is for allowing the first USIM terminal 1h-02 to autonomously transition to the RRC_IDLE state without a response from the base station, and a specific terminal operation may be as follows.

[0204] -If the first USIM terminal 1h-02 is configured to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1h-04 and needs to leave the RRC_CONNECTED state (if USIM 1 UE is configured to perform MUSIM assistance information or switching procedure for leaving RRC_CONNECTED state and if the USIM 1 UE needs to leave RRC_CONNECTED state), the first USIM terminal 1h-02 can start a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1h-04. To this end, when the first USIM terminal 1h-02 starts the UEAssistanceInformation procedure, it can start a T3xx timer with a musim-LeaveWithoutResponseTimer value set by the first base station 1h-04. When the first USIM terminal 1h-02 receives a predetermined RRC message (e.g., RRCRelease) from the first base station 1h-04, it can stop the T3xx timer that is running. If the first USIM terminal 1h-02 does not receive a predetermined RRC message from the first base station 1h-04 and the running T3xx timer expires, it can automatically transition to the RRC_IDLE state.

[0205] In step 1h-25, the second USIM terminal 1h-03 may inform the first USIM terminal 1h-02 to establish or re-establish an RRC connection with the second base station 1h-05.

[0206] In step 1h-30, the first USIM terminal configured to be able to perform the switching procedure for leaving RRC_CONNECTED state procedure from the first base station 1h-04 may determine whether the following modified condition A is satisfied.

[0207] - Modified condition A: If the first USIM terminal 1h-02 needs to leave the RRC connected mode due to Multi-USIM operation and has been configured by the first base station 1h-04 to perform the switching procedure for leaving RRC_CONNECTED state, the UE AssistanceInformation message including musim-PreferredRRC-state has not been transmitted to the first base station 1h-04 since the UE did not transmit a UE AssistanceInformation with musim-PreferredRRC-State and since it was configured to provide it and the UE needs to leave RRC_CONNECTED state

[0208] Or, the modified condition A can mean at least one of the following:

[0209] -If the first USIM terminal 1h-02 needs to leave the RRC connected mode due to a Multi-USIM operation and the timer T3xx is not running (if the UE needs to leave RRC_CONNECTED state and T3xx is not running) or if the first USIM terminal 1h-02 needs to leave the RRC connected mode due to a Multi-USIM operation and the musim-LeaveWithoutResponseTimer value is set but the timer T3xx is not running (if the UE needs to leave RRC_CONNECTED state and musim-LeaveWithoutResponseTimer is configured but T3xx is not running)

[0210] -When the first USIM terminal 1h-02 needs to leave the RRC connected mode due to a multi-USIM operation, the musim-LeaveWithoutResponseTimer value is not set, and the first base station 1h-04 has been set to be able to perform the switching procedure for leaving RRC_CONNECTED state procedure, and has not transmitted a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1h-04, or when the first USIM terminal 1h-02 needs to leave the RRC connected mode due to a multi-USIM operation, the musim-LeaveWithoutResponseTimer value is set, but the timer T3xx is not running.

[0211] In step 1h-35, if the modified condition A is satisfied, the first USIM terminal 1h-02 may initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state. Then, the first USIM terminal 1h-02 may start a T3xx timer with a musim-LeaveWithoutResponseTimer value if the musim-LeaveWithoutResponseTimer value is set from the first base station 1h-04. Then, the first USIM terminal 1h-02 may transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1h-04.

[0212] In step 1h-40, the first USIM terminal 1h-02 in the RRC connected mode (e.g., may be in the RRC connected mode without receiving a predetermined RRC message (e.g., RRCRelease) from the first base station 1h-04) is configured to perform a switching procedure for leaving RRC_CONNECTED state procedure from the first base station 1g-04, and can determine whether or not the modified condition A is satisfied. If the modified condition A described above is satisfied in step 1h-35, the first USIM terminal 1h-02 can not continuously retransmit a UEAssistanceInformation message including musim-PreferredRRC-state to the base station 1h-04.

[0213] FIG. 1I is a flowchart illustrating an embodiment of the present disclosure in which a terminal supporting multiple Universal Subscriber Identity Modules (USIMs) (Multi-USIM UE) performs an RRC connection re-establishment procedure with a base station associated with one USIM.

[0214] A multi-USIM terminal 1i-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. For convenience of explanation, the present disclosure will describe the embodiment based on a dual-USIM terminal supporting two USIMs. A dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, a dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or simultaneously receive data or information from base stations associated with each USIM.

[0215] Referring to FIG. 1I, the multi-USIM terminal 1i-01 may refer to a terminal that supports multiple USIMs. As an example, the multi-USIM terminal may refer to the first USIM terminal 1i-02 when operating in USIM 1, and may refer to the second USIM terminal 1i-03 when operating in USIM 2. A base station associated with each USIM may not recognize the multi-USIM terminal 1i-01 as one terminal, but may recognize each USIM separately. As an example, the first base station 1i-04 may recognize the first USIM terminal 1i-02 as one terminal, and the second base station 1i-05 may recognize the second USIM terminal 1i-03 as one terminal. Hereinafter, for convenience of explanation, in the embodiment of the present disclosure, when the multi-USIM terminal 1i-01 communicates using USIM 1, the multi-USIM terminal will be referred to as a first USIM terminal 1i-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal 1i-01 communicates using USIM 2, the multi-USIM terminal 1i-01 will be referred to as a second USIM terminal 1i-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal can be the first USIM terminal 1i-02 or the second USIM terminal 1i-03 depending on whether the multi-USIM terminal uses USIM 1 or USIM 2.

[0216] In step 1i-10, the first USIM terminal 1i-02 may establish an RRC connection with the first base station 1i-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1i-10, the second USIM terminal 1i-03 may not establish an RRC connection with the second base station 1i-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0217] In step 1i-15, the first USIM terminal 1i-02 may transmit a terminal capability information message (UECapabilityInformation) to the first base station 1i-04. The terminal capability information message may include at least one of the following information, which is of course not limited to the following examples:

[0218] -The first USIM terminal 1i-02 may include an indicator or information element that supports a procedure for switching from the RRC connected mode from the first base station 1i-04 to the second USIM terminal 1i-03 (support of switching procedure for leaving RRC_CONNECTED state). As an example, when the second USIM terminal 1i-03 establishes or resumes an RRC connection with the second base station 1i-05 and transitions to the RRC connected mode, the first USIM terminal 1i-02 may perform a procedure (i.e., a switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1i-04 of a desire to leave the RRC connected mode or to inform the first base station 1i-04 of a preferred RRC state (e.g., RRC idle mode, RRC inactive mode, or RRC connected mode).

[0219] -An indicator or information element indicating that the first USIM terminal 1i-02 supports a procedure for switching to the second USIM terminal 1i-03 while maintaining the RRC connected mode with the first base station 1i-04 (support of switching procedure without leaving RRC_CONNECTED state) may be included. As an example, a procedure for the second USIM terminal 1i-03 to perform an operation associated with the second base station 1i-05 while the first USIM terminal 1i-02 maintains the RRC connected mode with the first base station 1i-04 may be referred to as a switching procedure without leaving RRC_CONNECTED state, and an indicator or information element indicating that the first USIM terminal 1i-02 supports switching gaps required for switching to the second USIM terminal 1i-03 and communicating with the second base station 1i-05 while maintaining the RRC connected mode with the first base station 1i-04 (support of switching gaps for Multi-USIM purpose) may be included.

[0220] The switching gap may include a per UE level switching gap. If the first USIM terminal 1i-02 supports a per FR or per frequency switching gap, a separate indicator or information element indicating information regarding support for a per FR or per frequency switching gap may be included in the terminal capability information message.

[0221] In step 1i-20, the first base station 1i-04 may configure the first USIM terminal 1i-02 with configuration information (SwitchingGapReportingConfig) that allows the first USIM terminal 1i-02 to report preferred / required switching gap information for multi-USIM operation and / or the first USIM terminal 1i-02 to perform a switching procedure for leaving RRC_CONNECTED state procedure. This may be in accordance with the above-described embodiment.

[0222] In step 1i-30, the second USIM terminal 1i-03 may inform the first USIM terminal 1i-02 of information required to perform the operation described above in step 1i-25 in the RRC idle mode or the RRC inactive mode. For reference, step 1i-30 may be an operation performed inside the multi-USIM terminal 1i-01. That is, step 1i-30 is a step that does not require separate communication with a base station and is implemented only inside the multi-USIM terminal 1i-01, and may be a step that means data processing inside the multi-USIM terminal 1i-01 terminal and is not a required step. This may be in accordance with the above-mentioned embodiment.

[0223] In step 1i-35, the first USIM terminal 1i-02 may transmit a predetermined RRC message (e.g., a UE Assistance Information message or a new RRC message) including configuration information (SwitchingGapConfigPreference) for one or more preferred switching gap patterns to the first base station 1i-04. This may be in accordance with the above-described embodiment.

[0224] In step 1i-40, the first base station 1i-04 may transmit a predetermined RRC message (for example, RRCReconfiguration, RRCResume, or new RRC message) in which one or more switching gap setting information (SwitchingGapConfig or MUSIMGapConfig) is stored based on the SwitchingGapConfigPreference requested by the first USIM terminal 1i-02 as a response to step 1i-35. This may be in accordance with the above-described embodiment.

[0225] In step 1i-45, the first USIM terminal 1i-02 may transmit a predetermined RRC message to the first base station 1i-04 in response to the predetermined RRC message received in step 1i-40. As an example, the predetermined RRC message may be RRCReconfigurationComplete, RRCResumeComplete, or a new RRC message, etc. This may be in accordance with the above-described embodiment.

[0226] In step 1i-55, the first USIM terminal 1i-02 may start an RRC connection re-establishment procedure. When starting the RRC connection re-establishment procedure, the first USIM terminal 1i-02 may release the configuration information set in step 1i-20 and / or the configuration information set in step 1i-40. Then, the first USIM terminal 1i-02 may select a suitable NR cell through a cell selection process. For reference, the selected suitable NR cell may be a cell different from the PCell to which the first USIM terminal 1i-02 was connected before starting the RRC connection re-establishment procedure.

[0227] In step 1i-55, the first USIM terminal 1i-02 may transmit an RRCReestablishmentRequest message to the first base station 1i-04.

[0228] In step 1i-60, the first base station 1i-04 may transmit an RRCReestablishment message to the first USIM terminal 1i-02. In the present disclosure, when the first USIM terminal 1i-02 receives the RRCReestablishment message from the first base station 1i-04, it is proposed that the first USIM terminal 1i-02 releases the SwitchingGapConfig set in step 1i-40 (step 1i-63) (release the measurement gap configuration indicated by the SwitchingGapConfig, if configured). This is because the NR cell selected in step 1i-50 may be a cell different from the PCell to which the first USIM terminal 1i-02 was connected before starting the RRC connection re-establishment procedure, and therefore the SwitchingGapConfig already set in the first USIM terminal 1i-02 may not be valid, so that the first USIM terminal 1i-02 does not perform a Multi-USIM operation (i.e., an operation for the second USIM terminal) by releasing the SwitchingGapConfig already set autonomously. If the first USIM terminal 1i-02 does not autonomously release the existing SwitchingGapConfig but continues to maintain and apply it, when another first base station 1i-04 later provides service to the first USIM terminal 1i-02, the first USIM terminal 1i-02 may switch to the second USIM terminal 1i-04, which may result in a waste of resources of the first base station 1i-04.

[0229] In step 1i-65, the first USIM terminal 1i-02 may successfully perform the RRC connection re-establishment procedure by transmitting an RRCReestablishmentComplete message to the first base station 1i-04.

[0230] FIG. 1J is a diagram illustrating an operation of transmitting a UEAssistanceInformation message after a terminal supporting multiple Universal Subscriber Identity Modules (USIMs) (Multi-USIM UE) performs handover or conditional handover from a base station associated with one USIM according to one embodiment of the present disclosure.

[0231] A multi-USIM terminal 1j-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. For convenience of explanation, the present disclosure will describe the embodiment based on a dual-USIM terminal supporting two USIMs. The dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, the dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or simultaneously receive data or information from base stations associated with each USIM.

[0232] Referring to FIG. 1J, the multi-USIM terminal 1j-01 may refer to a terminal that supports multiple USIMs. As an example, the multi-USIM terminal may refer to the first USIM terminal 1j-02 when operating in USIM 1, and the second USIM terminal 1j-03 when operating in USIM 2. A base station associated with each USIM may recognize the multi-USIM terminal 1j-01 not as one terminal, but each USIM separately. As an example, the first base station 1j-04 may recognize the first USIM terminal 1j-02 as one terminal, and the second base station 1j-05 may recognize the second USIM terminal 1j-03 as one terminal. Hereinafter, for convenience of explanation, in the embodiment of the present disclosure, when the multi-USIM terminal 1j-01 communicates using USIM 1, the multi-USIM terminal 1j-01 will be referred to as a first USIM terminal 1j-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal communicates using USIM 2, the multi-USIM terminal 1j-01 will be referred to as a second USIM terminal 1j-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal 1j-01 can be the first USIM terminal 1j-02 or the second USIM terminal 1j-03 depending on whether the multi-USIM terminal 1j-01 uses USIM 1 or USIM 2.

[0233] In step 1j-10, the first USIM terminal 1j-02 may establish an RRC connection with the first base station 1j-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1j-10, the second USIM terminal 1j-03 may not establish an RRC connection with the second base station 1j-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0234] In step 1j-15, the first USIM terminal 1j-02 may transmit a terminal capability information message (UECapabilityInformation) to the first base station 1j-04. The terminal capability information message may include at least one of the following information:

[0235] -The first USIM terminal 1j-02 may include an indicator or information element that supports a procedure for switching from the first base station 1j-04 to the second USIM terminal 1j-03 away from the RRC connected mode. As an example, when the second USIM terminal 1j-03 establishes or resumes an RRC connection with the second base station 1j-05 and transitions to the RRC connected mode, the first USIM terminal 1j-02 may perform a procedure (i.e., a switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1j-04 of a desire to leave the RRC connected mode or to inform the first base station 1j-04 of a preferred RRC state (e.g., RRC idle mode, RRC inactive mode, or RRC connected mode).

[0236] -The first USIM terminal 1j-02 may include an indicator or information element that supports a procedure for switching to the second USIM terminal 1j-03 while maintaining an RRC connected mode with the first base station 1j-04 (support of switching procedure without leaving RRC_CONNECTED state). As an example, a procedure for the second USIM terminal 1j-03 to perform an operation associated with the second base station 1j-05 while the first USIM terminal 1j-02 maintains an RRC connected mode with the first base station 1j-04 may be referred to as a switching procedure without leaving RRC_CONNECTED state, and an indicator or information element that supports switching gaps required for the first USIM terminal 1j-02 to switch to the second USIM terminal 1j-03 and communicate with the second base station 1j-05 while maintaining an RRC connected mode with the first base station 1j-04 (support of switching gaps for Multi-USIM purpose) may be included.

[0237] The switching gap may include a per UE level switching gap. If the first USIM terminal 1j-02 supports a per FR or per frequency switching gap, a separate indicator or information element indicating information regarding support for a per FR or per frequency switching gap may be included in the terminal capability information message.

[0238] In step 1j-20, the first base station 1j-04 may be configured to allow the first USIM terminal 1j-02 to perform a switching procedure without leaving the RRC_CONNECTED state, which may be according to the embodiment described above.

[0239] In step 1j-25, the second USIM terminal 1j-03 may inform the first USIM terminal 1j-02 to establish or resume an RRC connection with the second base station 1j-05.

[0240] In step 1j-30, the first USIM terminal 1j-02, which is configured in step 1j-20 to perform the switching procedure for leaving RRC_CONNECTED state procedure from the first base station 1j-04, can initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state. This can be according to the above-mentioned embodiment.

[0241] In step 1j-35, the first USIM terminal 1j-02 may successfully perform handover or conditional handover with the first base station 1j-04. As an example, this may mean a case where a random access procedure is successfully performed with a target cell to which handover or conditional handover should be performed.

[0242] In step 1j-40, the first USIM terminal 1j-02 can determine whether the following condition X is satisfied.

[0243] -Condition X: The first USIM terminal 1j-02 judges the following contents sequentially or non-sequentially.

[0244] 1> If reconfigurationWithSync in the configuration information for performing handover or conditional handover in step 1j-35 was included in masterCellGroup or secondaryCellGroup (if reconfigurationWithySync was included in masterCellGroup or secondaryCellGroup)

[0245] 2> If the first USIM terminal 1j-02 has started to transmit a UEAssistanceInformation message to a corresponding cell group (e.g., a source cell group before performing handover or conditional handover) for the previous 1 second, and is still configured to provide UE assistance information in which the terminal is interested to the corresponding cell group (e.g., a target cell group after successfully performing handover or conditional handover), or the RRCReconfiguration message is applied due to a conditional reconfiguration condition, and the terminal is configured to provide a UEAssistanceInformation message to the corresponding cell group according to Section 5.7.4.2 of the standard 38.331, and then starts to transmit a UEAssistanceInformation message configured to transmit a UEAssistanceInformation message to the corresponding cell group (if the RRCReconfiguration message is applied due to a conditional reconfiguration execution, and the UE is configured to provide UE assistance information for the corresponding cell group, and the UE has initiated transmission of a UEAssistanceInformation message for the corresponding cell group since it was configured to do so in accordance with 5.7.4.2 in TS 38.331)

[0246] In step 1j-45, if condition X is satisfied, the first USIM terminal 1j-02 may initiate transmission of a UEAssistanceInformation message for the corresponding cell group in accordance with 5.7.4.3 in TS 38.331 to provide the concerned UE assistance information. As an example, the concerned UE assistance information may mean musim-PreferredRRC-State.

[0247] In step 1j-50, the terminal may start or restart a T3xx timer with the corresponding value if the musim-LeaveWithoutResponseTimer value is set.

[0248] FIG. 1K is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0249] Referring to the above drawing, the terminal may include an RF (Radio Frequency) processing unit 1k-10, a baseband processing unit 1k-20, a memory unit 1k-30, and a control unit 1k-40. Of course, the terminal is not limited to the above example, and may include fewer components than those shown in FIG. 1K, or may include more components than those shown in FIG.

[0250] The RF processing unit 1k-10 can perform functions for transmitting and receiving signals through a wireless channel, such as band conversion and amplification of signals. That is, the RF processing unit 1k-10 can upconvert a baseband signal provided from the baseband processing unit 1k-20 to an RF band signal and then transmit the signal through an antenna, and can downconvert an RF band signal received through an antenna to a baseband signal. For example, the RF processing unit 1k-10 can include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter (ADC), and the like. Although only one antenna is illustrated in FIG. 1K, the terminal can have multiple antennas. In addition, the RF processing unit 1k-10 can include multiple RF chains. Furthermore, the RF processing unit 1k-10 can perform beamforming. For beamforming, the RF processing unit 1k-10 can adjust the phase and magnitude of each of signals transmitted and received through multiple antennas or antenna elements. Furthermore, the RF processing unit 1k-10 can perform MIMO (Multi-Input Multi-Output) and can receive multiple layers when performing MIMO operations.

[0251] The baseband processor 1k-20 can perform a conversion function between a baseband signal and a bit string according to a physical layer protocol of the system. For example, when transmitting data, the baseband processor 1k-20 can generate complex symbols by encoding and modulating a transmission bit string. When receiving data, the baseband processor 1k-20 can restore a reception bit string by demodulating and decoding a baseband signal provided from the RF processor 1k-10. For example, in the case of an OFDM (Orthogonal Frequency Division Multiplexing) method, when transmitting data, the baseband processor 1k-20 can generate complex symbols by encoding and modulating a transmission bit string, map the complex symbols to subcarriers, and then configure OFDM symbols through an inverse fast Fourier transform (IFFT) operation and a cyclic prefix (CP) insertion. In addition, when receiving data, the baseband processing unit 1k-20 divides the baseband signal provided from the RF processing unit 1k-10 into OFDM symbol units, restores the signal mapped to the subcarrier through FFT (fast Fourier transform), and then restores the received bit string through demodulation and decoding.

[0252] The baseband processing unit 1k-20 and the RF processing unit 1k-10 transmit and receive signals as described above. Therefore, the baseband processing unit 1k-20 and the RF processing unit 1k-10 can be referred to as a transmitting unit, a receiving unit, a transceiver unit, or a communication unit. Furthermore, at least one of the baseband processing unit 1k-20 and the RF processing unit 1k-10 can include multiple communication modules to support multiple different wireless connection technologies. Also, at least one of the baseband processing unit 1k-20 and the RF processing unit 1k-10 can include different communication modules to process signals in different frequency bands. For example, the different wireless connection technologies can include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. Also, the different frequency bands can include centimeter wave (SHF: super high frequency) (e.g., 2.NRHz, NRhz) band, millimeter wave (e.g., 60GHz) band. The terminal can transmit and receive signals to and from the base station using the baseband processor 1k-20 and the RF processor 1k-10, and the signals can include control information and data.

[0253] The storage unit 1k-30 may store data such as a basic program, an application program, and setting information for the operation of the terminal. In particular, the storage unit 1k-30 may store information related to a second access node that performs wireless communication using a second wireless access technology. The storage unit 1k-30 may provide the stored data in response to a request from the control unit 1k-40. The storage unit 1k-30 may be configured with a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. The storage unit 1k-30 may also be configured with a plurality of memories. According to an embodiment, the storage unit 1k-30 may also store a program for performing a method in which the terminal supporting a plurality of USIMs transmits UE assistance information.

[0254] The control unit 1k-40 controls the overall operation of the terminal. For example, the control unit 1k-40 transmits and receives signals via the baseband processing unit 1k-20 and the RF processing unit 1k-10. The control unit 1k-40 can also record and read data in the storage unit 1k-40. To this end, the control unit 1k-40 can include at least one processor. For example, the control unit 1k-40 can include a CP (communication processor) that controls communication and an AP (application processor) that controls higher layers such as application programs. At least one configuration in the terminal can be implemented on one chip. According to an embodiment of the present disclosure, the control unit 1k-40 can also include a multiple connection processing unit 1k-42 that performs processing for operating in a multiple connection mode.

[0255] According to an embodiment of the present disclosure, the controller 1k-40 can control each component of the terminal to perform the above-described method of transmitting UE assistance information to a terminal supporting multiple USIMs. That is, each component of the terminal can operate to perform the above-described embodiment of the present disclosure.

[0256] FIG. 1L is a block diagram illustrating the structure of an NR base station according to one embodiment of the present disclosure.

[0257] As shown in Fig. 1L, the base station may include an RF processing unit 1l-10, a baseband processing unit 1l-20, a backhaul communication unit 1l-30, a storage unit 1l-40, and a control unit 1l-50. Of course, the base station is not limited to the above example, and may include fewer components than those shown in Fig. 1L, or may include more components.

[0258] The RF processing unit 1l-10 can perform functions for transmitting and receiving signals through a wireless channel, such as band conversion and amplification of signals. That is, the RF processing unit 1l-10 can upconvert a baseband signal provided from the baseband processing unit 1l-20 to an RF band signal and then transmit the signal through an antenna, and can downconvert an RF band signal received through the antenna to a baseband signal. For example, the RF processing unit 1l-10 can include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like. Although only one antenna is illustrated in FIG. 1L, the base station can have multiple antennas. In addition, the RF processing unit 1l-10 can include multiple RF chains. Furthermore, the RF processing unit 1l-10 can perform beamforming. For beamforming, the RF processing unit 1l-10 can adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform downlink MIMO operation by transmitting one or more layers.

[0259] The baseband processor 1l-20 can perform a conversion function between a baseband signal and a bit string according to a physical layer protocol of a predetermined access technology. For example, when transmitting data, the baseband processor 1l-20 can generate complex symbols by encoding and modulating a transmission bit string. Also, when receiving data, the baseband processor 1l-20 can restore a reception bit string by demodulating and decoding a baseband signal provided from the RF processor 1l-10. For example, in the case of OFDM, when transmitting data, the baseband processor 1l-20 can generate complex symbols by encoding and modulating a transmission bit string, map the complex symbols to subcarriers, and configure OFDM symbols through IFFT operation and CP insertion. Also, when receiving data, the baseband processor 1l-20 divides a baseband signal provided from the RF processor 1l-10 into OFDM symbol units, restores the signals mapped to subcarriers through FFT operation, and restores the reception bit string through demodulation and decoding. The baseband processing unit 1l-20 and the RF processing unit 1l-10 transmit and receive signals as described above. Thus, the baseband processing unit 1l-20 and the RF processing unit 1l-10 can be referred to as a transmitter, a receiver, a transceiver unit, a communication unit, or a wireless communication unit. A base station can transmit and receive signals to and from a terminal using the baseband processing unit 1l-20 and the RF processing unit 1l-10, and the signals can include control information and data.

[0260] The communication unit 1l-30 can provide an interface for communicating with other nodes in the network. That is, the communication unit 1l-30 can convert a bit string transmitted from a main base station to another node, such as a secondary base station or a core network, into a physical signal, and convert a physical signal received from another node into a bit string. The communication unit 1l-30 can be a backhaul communication unit.

[0261] The storage unit 1l-40 may store data such as a basic program, an application program, and setting information for the operation of the main base station. In particular, the storage unit 1l-40 may store information on a bearer assigned to a connected terminal, a measurement result reported from the connected terminal, and the like. The storage unit 1l-40 may also store information that is a criterion for determining whether to provide or interrupt a multiple connection to a terminal. The storage unit 1l-40 may provide the stored data in response to a request from the control unit 1l-50. The storage unit 1l-40 may provide the stored data in response to a request from the control unit 1l-50. The storage unit 1l-40 may be configured with a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. The storage unit 1l-40 may also be configured with a plurality of memories. According to an embodiment, the storage unit 1l-40 may also store a program for performing the above-mentioned method for a terminal supporting a plurality of USIMs to transmit UE Assistance Information.

[0262] The control unit 1l-50 controls the overall operation of the base station. For example, the control unit 1l-50 transmits and receives signals via the baseband processing unit 1l-20 and the RF processing unit 1l-10 or via the communication unit 1l-30. The control unit 1l-50 can also record and read data in the storage unit 1l-40. To this end, the control unit 1l-50 can include at least one processor. At least one configuration of the base station can be implemented on one chip. Each configuration of the base station can operate to perform the above-described embodiments of the present disclosure.

[0263] FIG. 1M is a diagram illustrating an embodiment of the present disclosure in which a terminal (Multi-USIM UE) supporting multiple Universal Subscriber Identity Modules (USIMs) releases an RRC connected mode (RRC_CONNECTED) from a base station associated with one USIM and performs an operation associated with another USIM.

[0264] A Multi-USIM terminal 1m-01 according to an embodiment of the present disclosure may include a terminal supporting two or more USIMs. For convenience of explanation, the present disclosure will describe an embodiment based on a Dual-USIM terminal supporting two USIMs. A Dual-USIM terminal can transmit data or information only to a base station associated with one USIM at a given time. Meanwhile, a Dual-USIM terminal can receive data or information from a base station associated with one USIM at a given time, or can receive data or information from base stations associated with each USIM simultaneously.

[0265] Referring to FIG. 1M, the multi-USIM terminal 1m-01 may refer to a terminal that supports multiple USIMs. As an example, the multi-USIM terminal may refer to the first USIM terminal 1m-02 when operating in USIM 1, and may refer to the second USIM terminal 1m-03 when operating in USIM 2. A base station associated with each USIM may recognize the multi-USIM terminal 1m-01 not as one terminal, but each USIM separately. As an example, the first base station 1m-04 may recognize the first USIM terminal 1m-02 as one terminal, and the second base station 1m-05 may recognize the second USIM terminal 1m-03 as one terminal. Hereinafter, for convenience of explanation, in the embodiment of the present disclosure, when the multi-USIM terminal 1m-01 communicates using USIM 1, the multi-USIM terminal 1m-01 will be referred to as a first USIM terminal 1m-02 or the terminal will be referred to as using the first USIM, and when the multi-USIM terminal 1m-01 communicates using USIM 2, the multi-USIM terminal will be referred to as a second USIM terminal 1m-03 or the terminal will be referred to as using the second USIM. That is, the multi-USIM terminal 1m-01 can be the first USIM terminal 1m-02 or the second USIM terminal 1m-03 depending on whether the multi-USIM terminal 1m-01 uses USIM 1 or USIM 2.

[0266] In step 1m-10, the first USIM terminal 1m-02 may establish an RRC connection with the first base station 1m-04 and be in an RRC connected mode (RRC_CONNECTED). Meanwhile, in step 1m-10, the second USIM terminal 1m-03 may not establish an RRC connection with the second base station 1m-05 and may be in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE).

[0267] In step 1m-15, the first USIM terminal 1m-02 may transmit a terminal capability information message (UECapabilityInformation) to the first base station 1m-04. The terminal capability information message may include at least one of the following information, which is of course not limited to the following examples:

[0268] -An indicator or information element that the first USIM terminal 1m-02 supports a procedure for switching from the RRC connected mode to the second USIM terminal 1m-03 from the first base station 1m-04 (support of switching procedure for leaving RRC_CONNECTED state) may be included. As an example, when the second USIM terminal 1m-03 establishes or resumes an RRC connection with the second base station 1m-05 and transitions to the RRC connected mode, the first USIM terminal 1m-02 may perform a procedure (i.e., a switching procedure for leaving RRC_CONNECTED state) to inform the first base station 1m-04 of a desire to leave the RRC connected mode or to inform the first base station 1m-04 of a preferred RRC state (e.g., RRC idle mode, RRC inactive mode, or RRC connected mode).

[0269] In step 1m-20, the first base station 1m-04 may configure the first USIM terminal 1m-02 to perform a switching procedure for leaving RRC_CONNECTED state. As an example, the first base station 1m-04 may configure the first USIM terminal 1m-02 to perform a switching procedure for leaving RRC_CONNECTED state via an RRCReconfiguration message in which otherConfig is stored.

[0270] Therefore, the first USIM terminal 1m-02 can determine that it can perform the switching procedure for leaving RRC_CONNECTED state. When the first base station 1m-04 configures the first USIM terminal 1m-02 to be able to perform the switching procedure for leaving RRC_CONNECTED state, it can transmit an RRCReconfiguration message including a new timer musim-LeaveWithoutResponseTimer value to the first USIM terminal 1m-02. The musim-LeaveWithoutResponseTimer value is for enabling the first USIM terminal 1m-02 to autonomously transition to the RRC_IDLE state without a response from the base station, and a specific terminal operation may be as follows.

[0271] -If the first USIM terminal 1m-02 is configured to perform a switching procedure for leaving RRC_CONNECTED state from the first base station 1m-04 and needs to leave the RRC_CONNECTED state (if USIM 1 UE is configured to perform MUSIM assistance information or switching procedure for leaving RRC_CONNECTED state and if the USIM 1 UE needs to leave RRC_CONNECTED state), the first USIM terminal 1m-02 can initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1m-04. To this end, when the first USIM terminal 1m-02 initiates the UEAssistanceInformation procedure, the first USIM terminal 1m-02 can start a T3xx timer with a musim-LeaveWithoutResponseTimer value set by the first base station 1m-04. The first USIM terminal 1m-02 can stop the running T3xx timer when it receives a predetermined RRC message (e.g., RRCRelease) from the first base station 1m-04. Alternatively, the first USIM terminal 1m-02 can stop the running T3xx timer when it later receives a release setting that disables the switching procedure for leaving RRC_CONNECTED state procedure from the first base station 1m-04 via an RRCReconfiguration message in which otherConfig is stored (e.g., musim-AssistanceConfigforLeaving is set to release).Alternatively, the first USIM terminal 1m-02 can stop the active T3xx timer if the musim-LeaveWithoutResponseTimer value is set by the first base station 1m-04 later via an RRCReconfiguration message containing otherConfig, or if the musim-LeaveWithoutResponseTimer value is not set. Of course, the first USIM terminal 1m-02 can restart the T3xx timer with the newly set musim-LeaveWithoutResponseTimer value if the first USIM terminal 1m-02 later receives a musim-LeaveWithoutResponseTimer value from the first base station 1m-04 via an RRCReconfiguration message containing otherConfig. If the first USIM terminal 1m-02 does not receive a specific RRC message from the first base station 1m-04 and the active T3xx timer expires, it can automatically transition to the RRC_IDLE state.

[0272] In step 1m-25, the second USIM terminal 1m-03 may inform the first USIM terminal 1m-02 to establish or resume an RRC connection with the second base station 1m-05.

[0273] In step 1m-30, the first USIM terminal 1m-02, which is configured to be able to perform the switching procedure for leaving RRC_CONNECTED state procedure from the first base station 1m-04, can determine whether or not the following modified condition A is satisfied.

[0274] - Modified condition A: If the first USIM terminal 1m-02 needs to leave the RRC connected mode due to Multi-USIM operation and has been configured by the first base station 1m-04 to perform the switching procedure for leaving RRC_CONNECTED state, the UEAssistanceInformation message including musim-PreferredRRC-state has not been transmitted to the first base station 1m-04 since the UE did not transmit a UEAssistanceInformation with musim-PreferredRRC-State and since it was configured to provide it and the UE needs to leave RRC_CONNECTED state

[0275] Or, the modified condition A can mean at least one of the following:

[0276] -If the first USIM terminal 1m-02 needs to leave the RRC connected mode due to Multi-USIM operation and the timer T3xx is not running (if the UE needs to leave RRC_CONNECTED state and T3xx is not running) or if the first USIM terminal 1m-02 needs to leave the RRC connected mode due to Multi-USIM operation and the musim-LeaveWithoutResponseTimer value is set but the timer T3xx is not running (if the UE needs to leave RRC_CONNECTED state and musim-LeaveWithoutResponseTimer is configured but T3xx is not running)

[0277] -When the first USIM terminal 1m-02 needs to leave the RRC connected mode due to a multi-USIM operation, the musim-LeaveWithoutResponseTimer value is not set, and the first base station 1m-04 has been set to be able to perform the switching procedure for leaving RRC_CONNECTED state procedure, and has not transmitted a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1m-04, or when the first USIM terminal 1m-02 needs to leave the RRC connected mode due to a multi-USIM operation, the musim-LeaveWithoutResponseTimer value is set, but the timer T3xx is not running.

[0278] In step 1m-35, if the modified condition A is satisfied, the first USIM terminal 1m-02 may initiate a UEAssistanceInformation procedure to transmit a UEAssistanceInformation message including musim-PreferredRRC-state. Then, the first USIM terminal 1m-02 may start a T3xx timer with a musim-LeaveWithoutResponseTimer value if the musim-LeaveWithoutResponseTimer value is set from the first base station 1m-04. Then, the first USIM terminal 1m-02 may transmit a UEAssistanceInformation message including musim-PreferredRRC-state to the first base station 1m-04.

[0279] In step 1m-40, the first base station 1m-04 may release related configuration information or not set the musim-LeaveWithoutResponseTimer value so that the first USIM terminal 1m-02 cannot perform the switching procedure for leaving RRC_CONNECTED state procedure. As an example, the first base station 1m-04 may set the first USIM terminal 1m-02 to be unable to perform the switching procedure for leaving RRC_CONNECTED state procedure via an RRCReconfiguration message in which otherConfig is stored. Specifically, the first base station 1m-04 may release related configuration information or not set the musim-LeaveWithoutResponseTimer value so that the first USIM terminal 1m-02 cannot perform the switching procedure for leaving RRC_CONNECTED state procedure by at least one of the following methods.

[0280] -Method 1: The first base station 1m-04 releases configuration information (e.g., musim-AssistanceConfigforLeaving) for the switching procedure for leaving RRC_CONNECTED state procedure for the first USIM terminal 1m-02.

[0281] In this case, the first USIM terminal 1m-02 determines that the first base station 1m-04 does not perform the switching procedure for leaving the RRC_CONNECTED state procedure. If the T3xx timer is running, the first USIM terminal 1m-02 can stop the running T3xx timer (step 1m-45). The first USIM terminal 1m-02 can maintain the RRC connection mode with the first base station 1m-04 (step 1m-50).

[0282] -Method 2: The first base station 1m-04 instructs the first USIM terminal 1m-02 via a new indicator that it cannot perform the switching procedure for leaving the RRC_CONNECTED state procedure.

[0283] In this case, the first USIM terminal 1m-02 determines that the first base station 1m-04 does not perform the switching procedure for leaving the RRC_CONNECTED state procedure. If the T3xx timer is running, the first USIM terminal 1m-02 can stop the running T3xx timer (step 1m-45). The first USIM terminal 1m-02 can maintain the RRC connection mode with the first base station 1m-04 (step 1m-50).

[0284] Method 3: The first base station 1m-04 does not set the musim-LeaveWithoutResponseTimer value to the first USIM terminal 1m-02.

[0285] If the T3xx timer is running, the first USIM terminal 1m-02 can stop the running T3xx timer (step 1m-45). The first USIM terminal 1m-02 can maintain the RRC connection mode with the first base station 1m-04 (step 1m-50).

[0286] -Method 4: The first base station 1m-04 releases all configuration information (e.g., musim-AssistanceConfig) for the switching procedure for leaving RRC_CONNECTED state and the switching procedure without leaving RRC_CONNECTED state to the first USIM terminal 1m-02.

[0287] In this case, the first USIM terminal 1m-02 determines that the first base station 1m-04 does not perform the switching procedure for leaving RRC_CONNECTED state procedure and the switching procedure without leaving RRC_CONNECTED state procedure. If the T3xx timer is running, the first USIM terminal 1m-02 can stop the running T3xx timer (step 1m-45). Of course, if the prohibit timer for the switching procedure without leaving RRC_CONNECTED state procedure is also running, it can be stopped. The first USIM terminal 1m-02 can maintain the RRC connection mode with the first base station 1m-04 (step 1m-50).

[0288] In step 1m-40, the first base station 1m-04 may reset the musim-LeaveWithoutResponseTimer value in the first USIM terminal 1m-02. In this case, if the T3xx timer is running, the first USIM terminal 1m-02 may stop the running T3xx timer (step 1m-45) or re-start the T3xx timer with the reset musim-LeaveWithoutResponseTimer value. The first USIM terminal 1m-02 may maintain the RRC connection mode with the first base station 1m-04 (step 1m-50).

[0289] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0290] In the case of a software implementation, a computer-readable storage medium may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute a method according to the embodiments described in the claims or specification of the present disclosure.

[0291] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), 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, magnetic cassette, or in a memory configured as a combination of some or all of these. Also, each of the constituent memories may include multiple pieces.

[0292] The program may also be stored in an attachable storage device that can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), or a storage area network (SAN), or a combination thereof. Such a storage device can be accessed by an apparatus that performs an embodiment of the present disclosure through an external port. Also, a separate storage device on the communication network can be accessed by an apparatus that performs an embodiment of the present disclosure.

[0293] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in the singular or plural form according to the specific embodiments presented. However, the expressions in the singular or plural form are selected to suit the circumstances presented for the convenience of explanation, and the present disclosure is not limited to the singular or plural components, and the components expressed in the plural form may be composed in the singular form, and the components expressed in the singular form may be composed in the plural form.

[0294] Meanwhile, although the detailed description of the present disclosure has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of the present disclosure as defined by the appended claims and the corresponding claims. [Explanation of symbols]

[0295] 1a-05, 1a-10, 1a-15, 1a-20 eNB 1a-25 MME 1a-30 S-GW 1a-35 User terminal 1c-05 NR CN 1c-10 NR gNB 1c-15 NR UE 1c-25 MME 1c-30 eNB

Claims

1. A method performed by a terminal supporting a multi-universal subscriber identity module (MUSIM) in a wireless communication system, the method comprising: receiving configuration information regarding MUSIM operation from a base station; If the terminal needs to leave the RRC connected state using the first USIM and a timer for state transition is not running, sending a UE assistance information message to the base station; and The method includes starting the timer based on configuration information related to the MUSIM operation.

2. The method comprises:

2. The method of claim 1, further comprising: transitioning from the RRC connected state using the first USIM if no response is received from the base station before expiration of a timer for the state transition after transmitting the UE assistance information message.

3. The method of claim 1 , wherein the UE assistance information message includes an RRC state preferred by the terminal.

4. The method comprises: the terminal performing a handover process; If a reconfigurationWithSync parameter is included in the configuration information for the handover process, and the UE assistance information message is sent to the base station within a predetermined time, and the UE assistance information message is configured to be sent to a target base station of the handover process, sending the UE assistance information message to the target base station of the handover process; and The method of claim 1 , further comprising the step of starting or restarting a timer for the state transition.

5. The method comprises: the terminal performing a handover process; If a reconfigurationWithSync parameter is included in the configuration information for the handover process, an RRCReconfiguration message is applied according to a conditional reconfiguration condition, the terminal is configured to provide the UE assistance information message, and the terminal starts to transmit the UE assistance information message to a target base station of the handover process, transmitting the UE assistance information message to the target base station of the handover process; and The method of claim 1 , further comprising the step of starting or restarting a timer for the state transition.

6. The UE assistance information message includes first preferred MUSIM gap information of the terminal; The method comprises: If the first preferred MUSIM gap information and the second preferred MUSIM gap information currently preferred by the terminal are different from each other and a timer for prohibiting a change of the MUSIM gap is not running, sending a UE assistance information message including the second preferred MUSIM gap information; and The method of claim 1 , further comprising the step of starting or restarting a timer for prohibiting modification of the MUSIM gap.

7. The method according to claim 6, wherein the UE does not transmit a UE assistance information message including the second preferred MUSIM gap information based on the second preferred MUSIM gap information being information obtained by excluding only non-periodic MUSIM gap information from the first preferred MUSIM gap information.

8. The setting information regarding the MUSIM operation is The method according to claim 1 , further comprising parameters relating to a timer for the state transition and a timer for prohibiting a change in the MUSIM gap.

9. The setting information regarding the MUSIM operation is The method of claim 1, comprising information regarding MUSIM gap information and MUSIM connection state switching.

10. The method comprises: receiving an RRC Reestablishment message from the base station; and The method according to claim 9 , further comprising the step of canceling the MUSIM gap information set based on the setting information.

11. A terminal supporting a multi-universal subscriber identity module (MUSIM) in a wireless communication system, the terminal comprising: A transceiver; and at least one processor coupled to the transceiver, the at least one processor comprising: receiving setting information regarding MUSIM operation from a base station; If the terminal needs to leave the RRC connected state using the first USIM and a timer for state transition is not running, sending a UE assistance information message to the base station; A terminal configured to start a timer for the state transition based on configuration information regarding the MUSIM operation.

12. The at least one processor 12. The terminal of claim 11, further comprising: transitioning from the RRC connected state using the first USIM if no response is received from the base station before expiration of a timer for the state transition after transmitting the UE assistance information message.

13. The terminal of claim 11, wherein the UE assistance information message includes an RRC state preferred by the terminal.

14. The at least one processor The terminal performs a handover process; If a reconfigurationWithSync parameter is included in the configuration information for the handover process, and the UE assistance information message is transmitted to the base station within a predetermined time, and the UE assistance information message is configured to be transmitted to a target base station of the handover process, transmitting the UE assistance information message to the target base station of the handover process; The terminal according to claim 11, which starts or restarts a timer for the state transition.

15. The at least one processor The terminal performs a handover process; If a reconfigurationWithSync parameter is included in the configuration information for the handover process, an RRCReconfiguration message is applied according to a conditional reconfiguration condition, the terminal is configured to provide the UE assistance information message, and the terminal starts transmitting the UE assistance information message to a target base station of the handover process, transmitting the UE assistance information message to a target base station of the handover process; The terminal according to claim 11, which starts or restarts a timer for the state transition.

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