Method and apparatus for performing communication in mobile communication system

Abstract

A user equipment (UE) includes a transceiver and a processor. The processor is configured to: receive, via the transceiver, a first message requesting UE capability information from a base station, in the event of receiving the first message: set a UE capability field of the UE capability information to include values applicable to all duplex modes and frequency ranges supported by the UE, in a case where the UE supports an additional function of FR1 compared to a function indicated by the set UE capability field, an FR1 additional UE capability field is included in the UE capability information, and the FR1 additional UE capability field is set to include a field reflecting the additional function of FR1, and in a case where the UE supports an additional function of FR2 compared to a function indicated by the set UE capability field, the FR1 additional UE capability field is set to include a field reflecting the additional function of FR2. The method includes receiving UE capability information, including an FR2 additional UE capability field in the UE capability information, and setting the FR2 additional UE capability field to include a field reflecting an additional function of the FR2, and transmitting, via the transceiver, a second message including the UE capability information to the base station as a response to the first message.

Description

[0001] This application is a divisional application of the application with the application date of October 31, 2019, application number 201980072466.3, and invention title "Method and apparatus for performing communication in a mobile communication system". Technical Field

[0002] The present disclosure relates to a mobile communication system, and more particularly, to a method and apparatus for performing communication between a base station (BS) and a user equipment (UE) in a mobile communication system. Background Art

[0003] To meet the growing demand for wireless data services after the commercialization of the fourth generation (4G) communication system, efforts have been made to develop an enhanced fifth generation (5G) new radio (NR) communication system. To achieve a high data transmission rate, the 5G communication system is designed to support ultra-high frequency bands (millimeter waves (mmWave)), for example, a frequency band of 28 GHz. To reduce the occurrence of stray radio waves and increase the transmission distance of radio waves in the ultra-high frequency band, various technologies for the 5G communication system are being studied, such as: beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas. In addition, different from the long-term evolution (LTE) system, the 5G communication system supports various subcarrier spacings, such as 15 kHz, 30 kHz, 60 kHz, and 120 kHz. The physical control channel uses polar coding, and the physical data channel uses low-density parity-check (LDPC). In addition, as a waveform for uplink transmission, not only cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM) is used, but also discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) is used. LTE can support hybrid automatic repeat request (HARQ) retransmission in a transport block (TB) unit, but 5G can additionally support HARQ retransmission in a code block group (CBG) unit in which multiple code blocks (CBs) are grouped.

[0004] To improve the system network of the 5G communication system, various technologies have been developed, including evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, vehicle-to-everything (V2X) networks, cooperative communication, coordinated multi-point (CoMP), and interference cancellation.

[0005] The Internet has evolved from a human-based connection network in which humans create and consume information to the Internet of Things (IoT) in which distributed configurations (such as objects) exchange information with each other to process information. The Internet of Everything (IoE) technology has emerged, in which IoT technology is combined with technologies such as those for processing big data through connection to a cloud server. To implement the IoT, various technical elements are required, such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, so that technologies related to sensor networks for connecting objects, machine-to-machine (M2M) communication, and machine type communication (MTC) have been studied in recent years. In the IoT environment, intelligent Internet technology (IT) services can be provided to collect and analyze data obtained from connected objects to create new value in human life. As existing information technology (IT) and various industries converge and combine with each other, the IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0006] For this reason, attempts are being made to apply the 5G communication system to the IoT network. For example, technologies related to sensor networks, M2M communication, and MTC are being implemented by using 5G communication technologies including beamforming, MIMO, and array antennas. Cloud radio access network (cloud RAN) as an application of the above big data processing technology may be an example of the convergence of 5G communication technology and IoT technology. In this way, various services can be provided to users in a communication system, and in order to provide various services to users, a method for providing each service within the same time period according to the characteristics of each service, and a device using this method are required. Various services provided by the 5G communication system are being studied, and one of the various services is a service that meets the requirements of low latency and high reliability. This service is called ultra-reliable and low-latency communication (URLLC).

[0007] Because various services can be provided due to the foregoing technical features and the development of wireless communication systems, methods for effectively providing these services are required. SUMMARY OF THE INVENTION

[0008] TECHNICAL PROBLEM

[0009] Because various services can be provided due to the foregoing technical features and the development of wireless communication systems, methods for effectively providing these services are required.

[0010] TECHNICAL SOLUTION

[0011] A user equipment (UE) for performing communication, the UE comprising: a transceiver; and a processor coupled to the transceiver and configured to: control the transceiver to receive a UE capability query, determine a UE capability field other than a frequency division duplex (FDD) additional UE capability field, a time division duplex (TDD) additional UE capability field, a frequency range 1 (FR 1) additional UE capability field, and a frequency range 2 (FR 2) additional UE capability field to include values applicable to all duplex modes and frequency ranges, and control the transceiver to send UE capability information based on the determined result.

[0012] A user equipment UE includes a transceiver and a processor. The processor is configured to: receive, via the transceiver, a first message from a base station requesting UE capability information, and in response to receiving the first message: set a UE capability field of the UE capability information to include values applicable to all duplex modes and frequency ranges supported by the UE, include an FR1 additional UE capability field in the UE capability information and set the FR1 additional UE capability field to include a field reflecting the additional functionality applicable to FR1 if the UE supports additional functionality for frequency range 1 FR1 compared to the functionality indicated by the set UE capability field, and include an FR2 additional UE capability field in the UE capability information and set the FR2 additional UE capability field to include a field reflecting the additional functionality applicable to FR2 if the UE supports additional functionality for frequency range 2 FR2 compared to the functionality indicated by the set UE capability field, and send, via the transceiver, a second message including the UE capability information to the base station as a response to the first message.

[0013] A base station for performing communication, the base station comprising a transceiver and a processor. The processor is configured to: send, via the transceiver, a first message to a user equipment UE requesting UE capability information, and receive, via the transceiver, a second message including UE capability information from the UE as a response to the first message, wherein the UE capability information includes a UE capability field set to include values applicable to all duplex modes and frequency ranges supported by the UE, wherein the UE capability information includes an FR1 additional UE capability field set to include a field reflecting the additional functionality of FR1 if the UE supports additional functionality for frequency range 1 FR1 compared to the functionality indicated by the UE capability field, and wherein the UE capability information includes an FR2 additional UE capability field set to include a field reflecting the additional functionality of FR2 if the UE supports additional functionality for frequency range 2 FR2 compared to the functionality indicated by the UE capability field.

[0014] A method performed by a user equipment UE, the method comprising: receiving, from a base station, a first message requesting UE capability information; in response to receiving the first message: setting a UE capability field of the UE capability information to include values applicable to all duplex modes and frequency ranges supported by the UE; in a case where the UE supports additional capabilities in frequency range 1 FR1 compared to the capabilities indicated by the set UE capability field, including an FR1 additional UE capability field in the UE capability information and setting the FR1 additional UE capability field to include fields reflecting the additional capabilities applicable to FR1, and in a case where the UE supports additional capabilities in frequency range 2 FR2 compared to the capabilities indicated by the set UE capability field, including an FR2 additional UE capability field in the UE capability information and setting the FR2 additional UE capability field to include fields reflecting the additional capabilities applicable to FR2, and sending, to the base station, a second message including the UE capability information as a response to the first message. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To more fully understand the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like components:

[0016] Figure 1A A diagram showing the architecture of a Long Term Evolution LTE system according to an embodiment of the present disclosure;

[0017] Figure 1B A diagram showing the radio protocol architecture of an LTE system according to an embodiment of the present disclosure;

[0018] Figure 1C A diagram showing the architecture of a next generation mobile communication system according to an embodiment of the present disclosure;

[0019] Figure 1D A diagram showing the radio protocol architecture of a next generation mobile communication system according to an embodiment of the present disclosure;

[0020] Figure 1E A diagram showing a process for describing the transition of a user equipment UE from a Radio Resource Control RRC connected mode to an RRC idle mode and from the RRC idle mode to the RRC connected mode according to the connection state between the UE and a base station BS according to an embodiment of the present disclosure;

[0021] Figure 1Fa 、 1Fb and 1Fc are diagrams for describing a process of transmitting and receiving UE radio access capability information between a BS and a UE in an RRC connected mode according to an embodiment of the present disclosure;

[0022] Figure 2A A diagram showing an example of a message flow between a UE and a BS when using a method of sending a scheduling request according to an embodiment of the present disclosure;

[0023] Figure 2B A flowchart showing an example of an operation sequence of a UE when using a method of sending a scheduling request according to an embodiment of the present disclosure;

[0024] Figure 3A A diagram showing a downlink (DL) and uplink (UL) channel frame structure for describing beam-based communication performed in a new radio (NR) system according to an embodiment of the present disclosure;

[0025] Figure 3B A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to an embodiment of the present disclosure;

[0026] Figure 3C A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure;

[0027] Figure 3D A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure;

[0028] Figure 3E A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure;

[0029] Figure 3F A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure;

[0030] Figure 3G A diagram showing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure.

[0031] Figure 3H A block diagram of a UE according to an embodiment of the present disclosure; and

[0032] Figure 3I A block diagram of a BS according to an embodiment of the present disclosure. Detailed Description

[0033] According to an embodiment of the present disclosure, a method for providing information about the capabilities of a user equipment (UE) in a mobile communication system is provided. According to an embodiment of the present disclosure, a method for using a plurality of scheduling request resources configured in a base station (BS) for a UE to request resources for data transmission in a mobile communication system is provided. According to an embodiment of the present disclosure, a method for a UE to perform cell reselection in response to channel bandwidth signaling in a mobile communication system is provided.

[0034] 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 of the disclosure.

[0035] According to an embodiment of the present disclosure, a user equipment (UE) for performing communication includes: a transceiver; and a processor coupled to the transceiver and configured to: control the transceiver to receive a UE capability query, determine UE capability fields other than a frequency division duplex (FDD) additional UE capability field, a time division duplex (TDD) additional UE capability field, a frequency range 1 (FR 1) additional UE capability field, and a frequency range 2 (FR 2) additional UE capability field to include values applicable to all duplex modes and frequency ranges, and control the transceiver to send UE capability information based on the determined result.

[0036] The processor may further be configured to, in a case where the UE supports functions of FDD and TDD and at least one of the UE capability fields has different values for FDD and TDD, determine, for FDD, whether the UE supports additional functions compared to the functions indicated by the previous UE capability field, and determine the FDD additional UE capability field to reflect the additional functions of FDD in response to the UE supporting the additional functions of FDD.

[0037] The processor may further be configured to, in a case where the UE supports functions of FDD and TDD and at least one of the UE capability fields has different values for FDD and TDD, determine, for TDD, whether the UE supports additional functions compared to the functions indicated by the previous UE capability field, and determine the TDD additional UE capability field to reflect the additional functions of TDD in response to the UE supporting the additional functions of TDD.

[0038] The processor may further be configured to, in a case where the UE supports functions of FR1 and FR2 and at least one of the UE capability fields has different values for FR1 and FR2, determine, for FR1, whether the UE supports additional functions compared to the functions indicated by the previous UE capability field, and determine the FR1 additional UE capability field to reflect the additional functions of FR1 in response to the UE supporting the additional functions of FR1.

[0039] The processor may also be configured to, when the UE supports the functions of FR1 and FR2 and at least one of the UE capability fields has different values for FR1 and FR2, determine, for FR2, whether the UE supports additional functions compared to the functions indicated by the previous UE capability field, and in response to the UE supporting the additional functions of FR2, determine an FR2 additional UE capability field to reflect the additional functions of FR2.

[0040] When the rat type of the UE capability query is set to nr, the UE capability field includes the UE-NR-capability field.

[0041] According to another embodiment of the present disclosure, a base station for performing communication includes: a transceiver; and a processor, coupled to the transceiver and configured to: control the transceiver to send a user equipment (UE) capability query, and receive UE capability information in response to the UE capability query, wherein the UE capability fields other than the FDD (Frequency Division Duplexing) additional UE capability field, the Time Division Duplexing (TDD) additional UE capability field, the Frequency Range 1 (FR 1) additional UE capability field, and the Frequency Range 2 (FR 2) additional UE capability field are determined to include values applicable to all duplex modes and frequency ranges.

[0042] According to another embodiment of the present disclosure, a method for performing communication by a user equipment (UE) includes: receiving a UE capability query; determining UE capability fields other than the Frequency Division Duplexing (FDD) additional UE capability field, the Time Division Duplexing (TDD) additional UE capability field, the FR 1 (Frequency Range 1) additional UE capability field, and the Frequency Range 2 (FR 2) additional UE capability field to include values applicable to all duplex modes and frequency ranges; and sending UE capability information based on the determined result.

[0043] According to an embodiment of the present disclosure, a method for performing communication by a base station includes: sending a UE capability query; and receiving UE capability information in response to the UE capability query, wherein the UE capability fields other than the FDD (Frequency Division Duplexing) additional UE capability field, the TDD (Time Division Duplexing) additional UE capability field, the Frequency Range 1 (FR 1) additional UE capability field, and the Frequency Range 2 (FR 2) additional UE capability field are determined to include values applicable to all duplex modes and frequency ranges.

[0044] Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: The terms "include" and "comprise," and derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated therewith," and derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or be connected with, couple to or be coupled with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or be bound with, have, have the property of, and the like; and the term "controller" means any device, system, or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware, software, or some combination of at least two thereof. It should be noted that the functions associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0045] In addition, the various functions described below may be implemented or supported by one or more computer programs, where each computer program is formed from computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, sets of instructions, procedures, functions, objects, classes, instances, related data, or portions thereof suitable for implementation in a suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD), or any other type of memory. A "non-transitory" computer-readable medium does not include a wired, wireless, optical, or other communication link that transmits transitory electrical or other signals. Non-transitory computer-readable media include media in which data can be permanently stored and media in which data can be stored and then rewritten, such as a rewritable compact disc or an erasable storage device.

[0046] Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art should understand that, in many if not most instances, such definitions apply to both the prior and future use of such defined words and phrases.

[0047] Inventive Mode

[0048] Discussed below Figures 1A to 3IAlso, the various embodiments used to describe the principles of the present disclosure in this patent document are merely exemplary and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented in any appropriately arranged system or device.

[0049] Hereinafter, the operating principles of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or configurations are not described in detail because they would obscure the present disclosure with unnecessary details. The terms used in the specification are defined in consideration of the functions used in the present disclosure and can be changed according to the intention of the user or operator or common methods. Therefore, the definitions of the terms are understood based on the entire description of this specification.

[0050] Throughout the present disclosure, the expression "at least one of a, b, or c" indicates only a, only b, only c, a and b, a and c, b and c, all of a, b, and c, or variations thereof.

[0051] Examples of terminals may include user equipment (UE), mobile station (MS), cellular phone, smart phone, computer, multimedia system capable of performing communication functions, and the like.

[0052] In the present disclosure, the controller may also be referred to as a processor.

[0053] Throughout this specification, a layer (or layer device) may also be referred to as an entity.

[0054] It should be understood that the blocks in the flowchart or combinations of flowcharts can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or another programmable data processing device, the instructions executed by the processor of the computer or another programmable data processing device create a unit for performing the functions described in the (multiple) flowchart blocks. The computer program instructions can be stored in a computer-usable or computer-readable memory capable of guiding the computer or another programmable data processing device to implement functions in a specific manner. Therefore, the instructions stored in the computer-usable or computer-readable memory can also produce a manufactured article containing an instruction unit for performing the functions described in the (multiple) flowchart blocks. The computer program instructions can also be loaded into the computer or another programmable data processing device. Thus, when a series of operations are executed in the computer or another programmable data processing device, the instructions for operating the computer or another programmable data processing device by generating a computer-executed process can provide operations for performing the functions described in the (multiple) flowchart blocks.

[0055] In addition, each block can represent a module, a segment, or a part of code that includes one or more executable instructions for performing the specified logical function(s). Note also that in some alternative embodiments, the functions recited in the blocks may occur out of order. For example, two consecutive blocks may be executed simultaneously according to the corresponding functions or in reverse order.

[0056] As used herein, the term "unit" represents a software element or a hardware element, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), and performs a certain function. However, the term "unit" is not limited to software or hardware. A "unit" may be formed in an addressable storage medium or may be formed to operate on one or more processors. Thus, for example, the term "unit" may include elements (e.g., software elements, object-oriented software elements, class elements, and task elements), processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, or variables. The functions provided by the elements and "units" may be combined into a smaller number of elements and "units" or may be divided into additional elements and "units". In addition, the elements and "units" may be embodied to reproduce one or more central processing units (CPUs) in a device or a secure multimedia card. Further, in embodiments of the present disclosure, a "unit" may include at least one processor.

[0057] In the present disclosure, the downlink (DL) refers to the radio transmission path of a signal to be sent from a base station (BS) to a UE, and the uplink (UL) refers to the radio transmission path of a signal to be sent from the UE to the BS. Although the following description may be provided as an example regarding a Long-Term Evolution (LTE) or an Advanced LTE (LTE-A) system, embodiments of the present disclosure are also applicable to other communication systems having a similar technical background or channel structure. For example, embodiments of the present disclosure may be applicable to a system including a fifth-generation (5G) New Radio (NR) communication technology developed after the LTE-A system, and hereinafter, 5G may indicate a concept including LTE, LTE-A, and other similar services according to related technologies. Without significantly departing from the scope of the present disclosure, through any modification by those of ordinary skill in the art, the present disclosure is applicable to other communication systems.

[0058] Hereinafter, for ease of explanation, terms for identifying access nodes, terms for indicating network entities, terms for indicating messages, terms for indicating interfaces between network entities, and terms for indicating various identification information used in the following description are exemplified. Thus, the present disclosure is not limited to the terms to be described below, and other terms indicating objects having the same technical meaning may be used.

[0059] For ease of description, the present disclosure uses terms and names defined in the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard. However, the present disclosure is not limited to these terms and names and can equally be applied to communication systems compliant with other standards. In the present disclosure, for ease of explanation, evolved Node B (eNB) may be used interchangeably with next generation Node B (gNB). That is, the BS described by eNB may represent gNB.

[0060] In the following description of the present disclosure, well-known functions or configurations are not described in detail because they would obscure the present disclosure with unnecessary details. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0061] Figure 1A A diagram showing the architecture of an LTE system according to an embodiment of the present disclosure.

[0062] Reference Figure 1A , the radio access network of the LTE system may include a plurality of next generation base stations (e.g., evolved Node B (eNB), Node B, or BS) 1a-05, 1a-10, 1a-15, and 1a-20, a mobility management entity (MME) 1a-25, and a serving gateway (S-GW) 1a-30. A UE (or terminal) 1a-35 may access an external network via eNB 1a-05, 1a-10, 1a-15, or 1a-20 and S-GW 1a-30.

[0063] In Figure 1A , eNB 1a-05, 1a-10, 1a-15, or 1a-20 may correspond to an existing Node B of a Universal Mobile Telecommunications System (UMTS). eNB 1a-05, 1a-10, 1a-15, or 1a-20 may be connected to UE 1a-35 via a wireless channel and perform complex functions compared to an existing Node B. In the LTE system, all user traffic data including real-time services such as Voice over Internet Protocol (VoIP) may be served through a shared channel. Therefore, an entity for performing scheduling by checking the status information of the UE, which includes buffer status information, available transmission power status information, and channel status information, may be required, and eNB 1a-05, 1a-10, 1a-15, or 1a-20 may operate as such an entity.

[0064] An eNB can generally control multiple cells. For example, an LTE system can use a radio access technology such as Orthogonal Frequency Division Multiplexing (OFDM) with a bandwidth of 20 MHz to achieve a data rate of 100 Mbps. The LTE system can also use Adaptive Modulation & Coding (AMC) to determine the modulation scheme and channel coding rate according to the channel state of UEs 1a - 35. eNBs 1a - 05, 1a - 10, 1a - 15, and 1a - 20, which are access nodes of the cellular network, can provide wireless access to UEs in the access network. That is, in order to serve the services of users, eNBs 1a - 05, 1a - 10, 1a - 15, and 1a - 20 can perform scheduling by checking the status information of UEs, which includes buffer status information, available transmit power status information, and channel status information, and can support the connection between the UE and the Core Network (CN).

[0065] The S - GW 1a - 30 is an entity for providing data bearers and can generate or remove data bearers under the control of the MME 1a - 25. The MME 1a - 25 is an entity for performing mobility management functions and various control functions on the UE 1a - 35 and can be connected to multiple eNBs 1a - 05, 1a - 10, 1a - 15, and 1a - 20.

[0066] The MME 1a - 25 and the S - GW 1a - 30 can also perform authentication, bearer management, etc. on UEs attempting to access the network and can process packets received from or to be sent to the eNBs 1a - 05, 1a - 10, 1a - 15, or 1a - 20.

[0067] Figure 1B A diagram showing the radio protocol architecture of an LTE system according to an embodiment of the present disclosure is shown.

[0068] Reference Figure 1B , the radio protocol architecture of the LTE system can include a Packet Data Convergence Protocol (PDCP) layer 1b - 05 and 1b - 40, a Radio Link Control (RLC) layer 1b - 10 and 1b - 35, a Media Access Control (MAC) layer 1b - 15 and 1b - 30, and a Physical (PHY) layer 1b - 20 and 1b - 25 for the UE and the LTE eNB, respectively. The PDCP layer 1b - 05 or 1b - 40 is responsible for, for example, Internet Protocol (IP) header compression / decompression. The main functions of the PDCP layer 1b - 05 or 1b - 40 are summarized as follows.

[0069] - Header compression and decompression: only Robust Header Compression (ROHC)

[0070] - Transfer of user data

[0071] - Deliver upper layer packet data units (PDUs) in sequence during the PDCP re - establishment procedure for RLC acknowledged mode (AM).

[0072] - For split bearers in DC (supported only for RLC AM): Routing of PDCP PDUs for transmission and re - ordering of PDCP PDUs for reception

[0073] - Re - detect lower layer service data units (SDUs) during the PDCP re - establishment procedure for RLC AM

[0074] - Retransmit PDCP PDUs during handover for RLC AM and re - transmit PDCP PDUs during the PDCP data recovery procedure for split bearers in DC

[0075] - Encryption and decryption

[0076] - Timer - based SDU discard in the uplink

[0077] For example, RLC layer 1b - 10 or 1b - 35 can perform automatic repeat request (ARQ) operations by re - configuring PDCP PDUs to an appropriate size. The main functions of RLC layer 1b - 10 or 1b - 35 are summarized as follows.

[0078] - Deliver upper layer PDUs

[0079] - Error correction by ARQ (only for AM data delivery)

[0080] - Concatenation, segmentation, and reassembly of RLC SDUs (only for unacknowledged mode (UM) and AM data delivery)

[0081] - Re - segmentation of RLC data PDUs (only for AM data delivery)

[0082] - Re - ordering of RLC data PDUs (only for UM and AM data delivery)

[0083] - Duplicate detection (only for UM and AM data delivery)

[0084] - Protocol error detection (only for AM data delivery)

[0085] - RLC SDU discard (only for UM and AM data delivery)

[0086] - RLC re - establishment

[0087] MAC layer 1b-15 or 1b-30 can be connected to multiple RLC layers configured for a UE, and can multiplex RLC PDUs into MAC PDUs and demultiplex RLC PDUs from MAC PDUs. The main functions of MAC layer 1b-15 or 1b-30 are summarized as follows.

[0088] - Mapping between logical channels and transport channels

[0089] - Multiplexing MAC SDUs belonging to one or different logical channels into transport blocks (TBs) delivered to / from the physical layer on a transport channel / Demultiplexing the MAC PDUs from the transport blocks (TBs)

[0090] - Scheduling information reporting

[0091] - Error correction by hybrid automatic repeat request (HARQ)

[0092] - Priority handling between logical channels of a UE

[0093] - Priority handling between UEs by dynamic scheduling

[0094] - Multimedia broadcast / multicast service (MBMS) service identification

[0095] - Transport format selection

[0096] - Padding

[0097] PHY layer 1b-20 or 1b-25 can encode and modulate the upper layer data channels into OFDM symbols and transmit the OFDM symbols through a wireless channel, or can demodulate the OFDM symbols received through the wireless channel, perform channel decoding on the OFDM symbols and deliver them to the upper layer.

[0098] The PHY layer 1b-20 or 1b-25 also uses HARQ for additional error correction, and the receiver sends 1-bit information indicating whether the packet sent from the transmitter has been received. Such information is referred to as HARQ acknowledgement (ACK) / negative acknowledgement (NACK) information. The DL HARQ ACK / NACK information for UL transmission can be sent through the Physical HARQ Indicator Channel (PHICH), and the UL HARQ ACK / NACK information for DL transmission can be sent through the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH). The PUSCH can be used for the UE to send not only HARQ ACK / NACK information to the eNB, but also Channel State Information (CSI), Scheduling Request (SR), etc. The SR is 1-bit information, and when the UE sends the SR in the resources in the PUCCH configured by the eNB, the eNB recognizes that the UE has data to be sent through the UL and thus allocates UL resources. The UE can send a detailed Buffer Status Report (BSR) through the UL resources. The eNB can allocate multiple SR resources to a single UE.

[0099] The PHY layer 1b-20 or 1b-25 may include one or more frequencies / carriers, and the technology of simultaneously configuring and using multiple frequencies by an eNB is referred to as Carrier Aggregation (CA). The CA technology can increase one carrier for communication between the UE and the E-UTRAN Node B (eNB) to one primary carrier and one or more secondary carriers, thus greatly increasing the data rate through multiple secondary carriers. In LTE, the cell using the primary carrier in the eNB is called the Primary Cell (PCell), and the cell using the secondary carrier is called the Secondary Cell (SCell). The technology of extending the CA capability to two eNBs is referred to as Dual Connectivity (DC) technology. In the DC technology, the UE can be simultaneously connected to the Master eNB (MeNB) and the Secondary eNB (SeNB) and can use both of them. The cell belonging to the MeNB can be called the Master Cell Group (MCG), and the cell belonging to the SeNB can be called the Secondary Cell Group (SCG). Each cell group can have a representative cell. The representative cell of the MCG can be called the PCell, and the representative cell of the SCG can be called the Primary Secondary Cell (PSCell). When using NR, the MCG is for LTE and the SCG is for NR, allowing the UE to use LTE and NR simultaneously.

[0100] Although not shown, there is an RRC layer above the PDCP layer of the UE and the base station, and the RRC layer can exchange control messages related to radio resource control access and measurement. For example, the eNB can indicate to the UE to perform measurements by using the messages of the RRC layer, and the UE can report the measurement results to the eNB by using the messages of the RRC layer.

[0101] Figure 1C A diagram showing the architecture of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0102] Reference Figure 1C , the radio access network of a next-generation mobile communication system (e.g., an NR or 5G system) includes a next-generation BS (e.g., a new radio node B (NR gNB or NR BS) 1c-10 and a new radio core network (NR CN) 1c-05. An NR UE (or NR terminal) 1c-15 can access an external network via the NR gNB 1c-10 and the NR CN 1c-05.

[0103] In Figure 1C , the NR gNB 1c-10 can correspond to an existing evolved node B (eNB) of an existing LTE system. The NR gNB 1c-10 can be connected to the NR UE 1c-15 via a radio channel and can provide better services compared to existing node Bs. In an NR or 5G system, all user traffic data can be served via a shared channel. Therefore, an entity for performing scheduling by checking, for example, buffer status information of the UE, available transmit power status information, and channel status information may be required, and the NR gNB 1c-10 can operate as such an entity. One NR gNB 1c-10 can control multiple cells. In an NR or 5G system, a bandwidth larger than the maximum bandwidth of an existing LTE system can be applied to achieve ultra-high data rates. In an NR or 5G system, beamforming technology can additionally be associated with OFDM as a radio access technology. In addition, AMC can also be used to determine a modulation scheme and a channel coding rate according to the channel state of the NR UE 1c-15.

[0104] The NR CN 1c-05 can perform functions such as mobility support, bearer establishment, and quality of service (QoS) configuration. The NR CN 1c-05 is an entity for performing mobility management functions and various control functions on the NR UE 1c-15 and can be connected to multiple base stations. An NR or 5G system can cooperate with an existing LTE system, and the NR CN 1c-05 can be connected to an MME 1c-25 via a network interface. The MME 1c-25 can be connected to an existing eNB 1c-30.

[0105] Figure 1D A diagram showing the radio protocol architecture of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0106] Reference Figure 1D, the radio protocol architecture of the next-generation mobile communication system may include NR Service Data Adaptation Protocol (SDAP) layers 1d-01 and 1d-45, NR PDCP layers 1d-05 and 1d-40, NR RLC layers 1d-10 and 1d-35, NR MAC layers 1d-15 and 1d-30, and NR PHY layers 1d-20 and 1d-25 for the UE and the NR gNB, respectively.

[0107] The main functions of the NR SDAP layer 1d-01 or 1d-45 may include some of the following.

[0108] - Transmit user plane data

[0109] - Mapping between QoS flows and data radio bearers (DRBs) for DL and UL

[0110] - Mark QoS flow identifiers (IDs) in DL and UL packets

[0111] - Reflect QoS flows for the mapping of UL SDAP PDUs to DRBs

[0112] Regarding the NR SDAP layer 1d-01 or 1d-45, information on whether to use the header of the NR SDAP layer 1d-01 or the functions of the NR SDAP layer 1d-01 can be configured for the UE by using radio resource control (RRC) messages for each PDCP layer, each bearer, or each logical channel. When configuring the SDAP header, a 1-bit non-access stratum (NAS) reflect QoS indicator and a 1-bit access stratum (AS) reflect QoS indicator of the SDAP header can be used to guide the UE to update or reconfigure UL and DL QoS flow and data bearer mapping information. The SDAP header may include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority information or scheduling information to appropriately support services.

[0113] The main functions of the NR PDCP layer 1d-05 or 1d-40 may include some of the following.

[0114] - Header compression and decompression: Only ROHC

[0115] - Transmit user data

[0116] - Deliver upper layer PDUs in sequence

[0117] - Deliver upper layer PDUs out of order

[0118] - Reorder PDCP PDUs for reception

[0119] - Detect duplicate lower layer SDUs

[0120] - Retransmission of PDCP SDU

[0121] *115 - Encryption and decryption

[0122] - Timer - based SDU discard in the uplink

[0123] In the foregoing description, the re - ordering function of the NR PDCP layer 1d - 05 or 1d - 40 may indicate the function of re - ordering the PDCP PDUs received from the lower layer based on the PDCP sequence number (SN). The re - ordering function of the NR PDCP layer 1d - 05 or 1d - 40 may include the function of delivering the re - ordered data to the upper layer in order or out - of - order, the function of recording the lost PDCP PDUs by re - ordering the received PDCP PDUs, the function of reporting the status information of the lost PDCP PDUs to the transmitter, or the function of requesting re - transmission of the lost PDCP PDUs.

[0124] The main functions of the NR RLC layer 1d - 10 or 1d - 35 may include at least some of the following.

[0125] - Delivery of upper - layer PDUs

[0126] - Sequential delivery of upper - layer PDUs

[0127] - Unordered delivery of upper - layer PDUs

[0128] - Error correction by ARQ

[0129] - Concatenation, segmentation, and reassembly of RLC SDUs

[0130] - Re - segmentation of RLC data PDUs

[0131] - Re - ordering of RLC data PDUs

[0132] - Duplicate detection

[0133] - Protocol error detection

[0134] - RLC SDU discard

[0135] - RLC re - establishment

[0136] In the above description, the sequential delivery function of the NR RLC layer 1d - 10 or 1d - 35 may indicate the function of delivering the RLC SDUs received from the lower layer to the upper layer in sequence. When multiple RLC SDUs segmented from one RLC SDU are received, the sequential delivery function of the NR RLC layer 1d - 10 or 1d - 35 may include the function of reassembling the RLC SDUs and delivering the reassembled RLC SDUs.

[0137] The sequential delivery function of the NR RLC layer 1d-10 or 1d-35 may include at least one of the functions of reordering the received RLC PDUs based on the RLC SN or PDCP SN, recording the lost RLC PDUs by reordering the received RLC PDUs, reporting the status information of the lost RLC PDUs to the transmitter, or requesting retransmission of the lost RLC PDUs.

[0138] When there are lost RLC SDUs, the sequential delivery function of the NR RLC layer 1d-10 or 1d-35 may include the function of delivering only the RLC SDUs before the lost RLC SDUs to the upper layer.

[0139] The sequential delivery function of the NR RLC layer 1d-10 or 1d-35 may include the function of delivering all the RLC SDUs received before the start of the timer to the upper layer in sequence when a certain timer expires, even when there are lost RLC SDUs.

[0140] The sequential delivery function of the NR RLC layer 1d-10 or 1d-35 may include the function of delivering all the RLC SDUs received up to the current time to the upper layer in sequence when a certain timer expires, even when there are lost RLC SDUs.

[0141] The NR RLC layer 1d-10 or 1d-35 may process the RLC PDUs in the received order and may deliver the RLC PDUs to the NR PDCP layer 1d-05 or 1d-40 regardless of the SN (unordered delivery).

[0142] When a segmentation is received, the NR RLC layer 1d-10 or 1d-35 may recombine the segmentation with other segments stored in the buffer or subsequently received into a complete RLC PDU and may deliver the RLC PDU to the NR PDCP layer 1d-05 or 1d-40.

[0143] The NR RLC layer 1d-10 or 1d-35 may not have a concatenation function, and this concatenation function may be performed by the NR MAC layer 1d-15 and 1d-30, or replaced by the multiplexing function of the NR MAC layer 1d-15 and 1d-30.

[0144] In the above description, the disordered delivery function of the NR RLC layer 1d-10 or 1d-35 may refer to the function of directly delivering the RLC SDUs received from the lower layer to the upper layer in a disordered manner. The disordered delivery function of the NR RLC layer 1d-10 or 1d-35 may include the function of reassembling multiple RLC SDUs segmented from one RLC SDU, and delivering the reassembled RLC SDU when the segmented RLC SDU is received. The disordered delivery function of the NR RLC layer 1d-10 or 1d-35 may include the function of recording lost RLC PDUs by storing the RLC PDUs or PDCP PDUs of the received RLC PDUs and reordering the received RLC PDUs.

[0145] The NR MAC layers 1d-15 and 1d-30 may be connected to multiple NR RLC layers configured for one UE, and the main functions of the NR MAC layers 1d-15 and 1d-30 may include some of the following functions.

[0146] - Mapping between logical channels and transport channels

[0147] - Multiplexing / demultiplexing of MAC SDUs

[0148] - Scheduling information reporting

[0149] - Error correction via HARQ

[0150] - Priority handling between logical channels of one UE

[0151] - Priority handling between UEs via dynamic scheduling

[0152] - MBMS service identification

[0153] - Transmission format selection

[0154] - Padding

[0155] The NR PHY layers 1d-20 and 1d-25 may encode and modulate the upper layer data channels into OFDM symbols and transmit the OFDM symbols through the wireless channel, or may demodulate the OFDM symbols received through the wireless channel, perform channel decoding on the OFDM symbols, and deliver them to the upper layer.

[0156] Figure 1E A diagram is shown for describing the process of transitioning from the RRC connected mode to the RRC idle mode and from the RRC idle mode to the RRC connected mode performed by a UE according to an embodiment of the present disclosure based on the connection state between the UE and a BS including an eNB, a gNB, etc.

[0157] According to an embodiment of the present disclosure, when a UE configured to transmit and receive data in the RRC connected mode does not transmit or receive data due to a predetermined reason or within a predetermined time, the BS may send an RRC Connection Release message to the UE to allow the UE to transition to the RRC idle mode (1e-01). Thereafter, when a UE that is currently not configured for connection (hereinafter also referred to as an idle mode UE) has data to transmit or receive, the UE may perform an RRC connection establishment procedure on the BS.

[0158] The UE may establish reverse transmission synchronization with the BS through a random access procedure and may send an RRC Connection Request message (1e-05) to the BS. The RRC Connection Request message may include an identifier of the UE, a reason for establishment, and the like.

[0159] The BS may send an RRC Connection Setup message to allow the UE to establish an RRC connection (1e-10). The RRC Connection Setup message may include RRC connection configuration information and the like. The RRC connection may also be described as a signaling radio bearer (SRB) and may be used to transmit and receive RRC messages that are control messages between the UE and the BS.

[0160] The UE that has established the RRC connection may send an RRC Connection Setup Complete message (1e-15) to the BS. The RRC Connection Setup Complete message may include a control message of a service request (SERVICE REQUEST) for establishing a bearer for a service requested by the UE from the MME or the access mobility management function (AMF).

[0161] The BS may send a control message of the service request included in the RRC Connection Setup Complete message to the MME or the AMF (1e-20), and the MME or the AMF may determine whether to provide the service requested by the UE.

[0162] As a result of the determination, when the MME or the AMF determines to provide the service requested by the UE, the MME or the AMF may send an Initial Context Setup Request message (1e-25) to the BS. The Initial Context Setup Request message may include QoS information to be applied to the DRB configuration, security information to be applied to the DRB (e.g., a security key, a security algorithm, etc.), and the like.

[0163] The BS can exchange a SecurityModeCommand message (1e-30) and a SecurityModeComplete message (1e-35) with the UE to configure security.

[0164] When the security configuration is completed, the BS can send an RRCConnectionReconfiguration message (1e-40) to the UE. The RRCConnectionReconfiguration message can include configuration information about the DRB to handle user data, and the UE can configure the DRB by using the configuration information about the DRB and can send an RRCConnectionReconfigurationComplete message (1e-45) to the BS.

[0165] After the BS completes the DRB configuration with the UE, the BS can send an INITIAL CONTEXT SETUP COMPLETE message to the MME or AMF (1e-50), and upon receiving this message, the MME or AMF exchanges a BEARER SETUP message and a BEARER SETUP RESPONSE message (1e-55 and 1e-60) with the S-GW or the User Plane Function (UPF) to configure the S1 bearer. The S1 bearer indicates the connection established between the S-GW or UPF and the BS for data transmission and can correspond one-to-one to the DRB.

[0166] When the foregoing process is completed, the UE can send and receive data to / from the BS via the S-GW or UPF (1e-65 and 1e-70). As described above, the general data transmission process can consist of approximately three steps, namely, RRC connection configuration, security configuration, and DRB configuration.

[0167] Due to predefined reasons, the BS can send an RRCConnectionReconfiguration message to newly allocate, add, or change the configuration for the UE (1e-75).

[0168] Figure 1Fa A diagram is shown for describing the process of transmitting and receiving UE radio access capability information between a BS 1f-02 including an eNB, a gNB, etc. and a UE 1f-01 in the RRC connected mode according to an embodiment of the present disclosure.

[0169] According to an embodiment of the present disclosure, when requesting UE radio access capability information and / or additionally requesting UE radio access capability information, BS1f-02 may send a UECapabilityEnquiry message (1f-05) to UE 1f-01 in the RRC connected mode. The UECapabilityEnquiry message may be sent when BS1f-02 requests the UE radio access capability (also referred to as UE capability) of the UE 1f-01 with respect to NR and additionally requests the UE radio access capability of the UE with respect to a radio access technology (RAT). Therefore, the UECapabilityEnquiry message may include a UE-CapabilityRAT-RequestList information element (IE), which is a list of user capability requests for one or more RATs, and the UE-CapabilityRAT-Request for requesting the user capability for each RAT may include the following information.

[0170] - rat-Type: The RAT type for which the network requests the UE capability (the RAT type for which the network requests the UE capability). For example, one of the RAT types may be set as rat-Type, and the RAT types include nr, eutra-nr, eutra, and multi-radio dual connectivity (MR-DC) excluding eutra-nr.

[0171] - capabilityRequestFilter: Information for which the network requests the UE to filter the UE capability (information for which the network requests the UE to filter the UE capability). For example, when rat-Type is set to nr, capabilityRequestFilter may include the information defined in UE-CapabilityRequestFilterNR (e.g., the value of frequencyBandlist or FreqBandList with respect to NR).

[0172] When UE 1f-01 in the RRC connected mode receives the UECapabilityEnquiry message from BS1f-02, UE 1f-01 may deliver the UE radio access capability by sending a UECapabilityInformation message to BS1f-02 (1f-10). The UECapabilityInformation message may include a UE-CapabilityRAT-ContainerList IE as a list of UE capability containers for one or more RATs, and the UE-CapabilityRAT-Container as a UE capability container for each RAT may include the following information.

[0173] -rat-Type: The RAT type supported by UE 1f-01 in the RRC connected mode. For example, one of the RAT types can be set as rat-Type, and the RAT types include nr, eutra-nr, eutra, and MR-DC does not include eutra-nr. For example, according to the method of setting the RAT type, when UE 1f-01 supports NR among the RATs requested by BS1f-02 in 1f-05, the RAT type can be set as nr.

[0174] -ue-CapabilityRAT-Container: A container including UE capability information indicated by rat-Type. For example, when rat-Type is set as nr, ue-CapabilityRAT-Container can include the information defined in UE-NR-Capability (NR UE radio access capability parameter).

[0175] In 1f-10, when UE 1f-01 in the RRC connected mode sends a UECapabilityInformation message to BS1f-02, UE 1f-01 performs the following operations.

[0176] 1> When the UECapabilityEnquiry message received in 1f-05 includes nr and UE 1f-01 supports NR:

[0177] 2> UE 1f-01 can set rat-Type as nr and can include UE-NR-Capability in ue-CapabilityRAT-Container. In this regard, according to an embodiment of the present disclosure, the method of including UE-NR-Capability performed by UE 1f-01 can be one of the following methods.

[0178] * When UE 1f-01 supports all of frequency division duplexing (FDD), time division duplexing (TDD), frequency range 1 (FR1), and frequency range 2 (FR2),

[0179] - UE 1f-01 can set all fields of UE-NR-Capability except fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to FDD, TDD, FR1, and FR2 (Set all fields of UE-NR-Capability except fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to FDD, TDD, FR1, and FR2).

[0180] - When some fields of UE-NR-Capability have different values for FDD and TDD (If (some) UE capability fields have different values for FDD and TDD),

[0181] ◇ In the case of FDD, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-NR-Capability (If for FDD, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR-Capability),

[0182] ● UE 1f-01 can include the fdd-Add-UE-NR-Capabilities field in UE-NR-Capability and can set the fdd-Add-UE-NR-Capabilities field to include field values reflecting other additional functions applicable to FDD (Include the field fdd-Add-UE-NR-Capabilities and set it to include fields reflecting additional functions applicable to FDD).

[0183] ◇ In the case of TDD, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-NR-Capability,

[0184] ● UE 1f-01 can include the tdd-Add-UE-NR-Capabilities field in UE-NR-Capability and can set the tdd-Add-UE-NR-Capabilities field to include field values reflecting other additional functions applicable to TDD).

[0185] - When some fields of UE-NR-Capability have different values for FR1 and FR2,

[0186] ◇ In the case of FR1, when UE 1f-01 must support additional functions, compared with the settings of the previous fields of UE-NR-Capability,

[0187] UE 1f-01 may include the fr1-Add-UE-NR-Capabilities field in UE-NR-Capability and may set the fr1-Add-UE-NR-Capabilities field to include field values on which other additional functions applicable to FR1 are reflected. (Include the field fr1-Add-UE-NR-Capabilities and set it to include the field reflecting the additional functions applicable to FR1).

[0188] ◇ In the case of FR2, when UE 1f-01 must support additional functions, compared with the settings of the previous fields of UE-NR-Capability (if for FR2, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR-Capability),

[0189] ● UE 1f-01 may include the fr2-Add-UE-NR-Capabilities field in UE-NR-Capability and may set the fr2-Add-UE-NR-Capabilities field to include field values on which other additional functions applicable to FR2 are reflected. (Include the field fr2-Add-UE-NR-Capabilities and set it to include the field reflecting the additional functions applicable to FR2).

[0190] * When UE 1f-01 supports both FDD and TDD and supports one of FR1 and FR2 (in this disclosure, FRx is used to indicate one of FR1 and FR2) (otherwise, if the UE supports both FDD and TDD and a single FRx),

[0191] - UE 1f-01 can set all fields of UE-NR-Capability except for fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE--NR-Capabilies, and fr2-Add-UE-NR-Capabilities to include values applicable to FDD, TDD, and FRx (Set all fields of UE-NR-Capability except for fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE--NR-Capabilies, and fr2-Add-UE-NR-Capabilities to include values applicable to FDD, TDD, and FRx).

[0192] - When some fields of UE-NR-Capability have different values for FDD and TDD (If (some) UE capability fields have different values for FDD and TDD),

[0193] ◇ In the case of FDD, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-NR-Capability (If for FDD, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR-Capability),

[0194] · UE 1f-01 can include the fdd-Add-UE-NR-Capabilities field in UE-NR-Capability and can set the fdd-Add-UE-NR-Capabilities field to include field values on which other additional functions applicable to FDD are reflected (Include the field fdd-Add-UE-NR-Capabilities and set it to include the fields reflecting the additional functions applicable to FDD).

[0195] ◇ In the case of TDD, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-NR-Capability (If for TDD, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR-Capability),

[0196] · The UE 1f-01 may include a tdd-Add-UE-NR-Capabilities field in the UE-NR-Capability, and may set the tdd-Add-UE-NR-Capabilities field to include a field value on which other additional capabilities applicable to TDD are reflected (including the field tdd-Add-UE-NR-Capabilities and setting it to include a field reflecting additional capabilities applicable to TDD).

[0197] * When the UE 1f-01 supports one of FDD and TDD (in this disclosure, xDD is used to indicate one of FDD and TDD), and supports both FR1 and FR2 (otherwise if the UE supports a single xDD mode and both FR1 and FR2),

[0198] - The UE 1f-01 may set all fields of the UE-NR-Capability other than fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD, FR1, and FR2 (set all fields of the UE-NR-Capability other than fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD, FR1, and FR2).

[0199] - The UE 1f-01 may set all fields of the UE-NR-Capability other than fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD, FR1, and FR2 (set all fields of the UE-NR-Capability other than fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD, FR1, and FR2).

[0200] - When some fields of UE-NR-Capability have different values for FR1 and FR2 (if (some) UE capability fields have different values for FR1 and FR2),

[0201] ◇ In the case of FR1, when UE 1f-01 has to support additional capabilities, compared to the setting of the previous fields of UE-NR-Capability (if for FR1, the UE supports additional capabilities compared to the capabilities indicated by the previous fields of UE-NR-Capability),

[0202] · UE 1f-01 may include the fr1-Add-UE-NR-Capabilities field in UE-NR-Capability and may set the fr1-Add-UE-NR-Capabilities field to include field values on which other additional capabilities applicable to FR1 are reflected. (Include the field fr1-Add-UE-NR-Capabilities and set it to include the fields reflecting the additional capabilities applicable to FR1).

[0203] ◇ In the case of FR2, when UE 1f-01 has to support additional capabilities, compared to the setting of the previous fields of UE-NR-Capability (if for FR2, the UE supports additional capabilities compared to the capabilities indicated by the previous fields of UE-NR-Capability),

[0204] · UE 1f-01 may include the fr2-Add-UE-NR-Capabilities field in UE-NR-Capability and may set the fr2-Add-UE-NR-Capabilities field to include field values on which other additional capabilities applicable to FR2 are reflected. (Include the field fr2-Add-UE-NR-Capabilities and set it to include the fields reflecting the additional capabilities applicable to FR2).

[0205] * When UE 1f-01 supports one of FDD and TDD and supports one of FR1 and FR2 (otherwise if the UE supports a single xDD mode and a single FRx),

[0206] - UE 1f-01 can set all fields of UE-NR-Capability except fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD and FRx (set all fields of UE-NR-Capability except fdd-Add-UE-NR-Capabilities, tdd-Add-UE-NR-Capabilities, fr1-Add-UE-NR-Capabilities, and fr2-Add-UE-NR-Capabilities to include values applicable to xDD and FRx).

[0207] 2> UE 1f-01 can include supported NR band combinations in supportedBandCombination.

[0208] 1> When the UECapabilityEnquiry message received in 1f-05 includes eutra and UE1f-01 supports E-UTRA:

[0209] 2> UE 1f-01 can set rat-Type to eutra and can include UE-EUTRA-Capability in ue-CapabilityRAT-Container. In this regard, the method of including UE-EUTRA-Capability performed by UE 1f-01 can be determined according to "36.306: Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) Radio Access Capability".

[0210] 1> When the UECapabilityEnquiry message received in 1f-05 includes one of the MR-DCs other than eutra-nr or eutra-nr and UE1f-01 supports the indicated MR-DC:

[0211] 2> UE 1f-01 can set rat-Type to one of the MR-DCs other than eutra-nr or eutra-nr and can include UE-MRDC-Capability in ue-CapabilityRAT-Container. In this regard, according to an embodiment of the present disclosure, the method of including UE-MRDC-Capability performed by UE 1f-01 can be one of the following methods.

[0212] *When the UE 1f-01 supports all of FDD, TDD, FR1, and FR2,

[0213] - The UE 1f-01 can set all fields of UE-MRDC-Capability except for fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to FDD, TDD, FR1, and FR2 (set all fields of UE-MRDC-Capability except for fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to FDD, TDD, FR1, and FR2).

[0214] - When some fields of UE-MRDC-Capability have different values for FDD and TDD (if (some) UE capability fields have different values for FDD and TDD),

[0215] ◇ In the case of FDD, when the UE 1f-01 must support additional functions, compared to the setting of the previous fields of UE-MDRC-Capability (if for FDD, the UE supports additional functions compared to the functions indicated by the previous fields of UE-MRDC-Capability),

[0216] · The UE 1f-01 can include the fdd-Add-UE-MRDC-Capabilities field in UE-MRDC-Capability and can set the fdd-Add-UE-MRDC-Capabilities field to include field values on which other additional functions applicable to FDD are reflected (include the field fdd-Add-UE-MRDC-Capabilities and set it to include the field reflecting the additional functions applicable to FDD).

[0217] ◇In the case of TDD, when UE 1f-01 must support additional functions, compared with the setting of the previous field of UE-MRDC-Capability (if for TDD, the UE supports additional functions compared with the functions indicated by the previous field of UE-MRDC-Capability),

[0218] ·UE 1f-01 may include the tdd-Add-UE-MRDC-Capabilities field in UE-MRDC-Capability, and may set the tdd-Add-UE-MRDC-Capabilities field to include a field value on which other additional functions applicable to TDD are reflected (including the field tdd-Add-UE-MRDC-Capabilities, and setting it to include a field reflecting additional functions applicable to TDD).

[0219] -When some fields of UE-MRDC-Capability have different values for FR1 and FR2 (if (some) UE capability fields have different values for FR1 and FR2),

[0220] ◇In the case of FR1, when UE 1f-01 must support additional functions, compared with the setting of the previous field of UE-MRDC-Capability (if for FR1, the UE supports additional functions compared with the functions indicated by the previous field of UE-MRDC-Capability),

[0221] ·UE 1f-01 may include the fr1-Add-UE-MRDC-Capabilities field in UE-MRDC-Capability, and may set the fr1-Add-UE-MRDC-Capabilities field to include a field value on which other additional functions applicable to FR1 are reflected. (including the field fr1-Add-UE-MRDC-Capabilities, and setting it to include a field reflecting additional functions applicable to FR1).

[0222] ◇In the case of FR2, when UE 1f-01 must support additional functions, compared with the setting of the previous field of UE-MRDC-Capability (if for FR2, the UE supports additional functions compared with the functions indicated by the previous field of UE-MRDC-Capability),

[0223] · The UE 1f-01 may include a fr2-Add-UE-MRDC-Capabilities field in the UE-MRDC-Capability, and may set the fr2-Add-UE-MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR2 are reflected. (Including the field fr2-Add-UE-MRDC-Capabilities and setting it to include a field reflecting additional capabilities applicable to FR2).

[0224] * When the UE 1f-01 supports both FDD and TDD and supports one of FR1 and FR2 (in the present disclosure, FRx is used to indicate one of FR1 and FR2) (otherwise, if the UE supports both FDD and TDD and a single FRx),

[0225] - The UE 1f-01 may set all fields of the UE-MRDC-Capability other than fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to FDD, TDD, and FRx (setting all fields of the UE-MRDC-Capability other than fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to FDD, TDD, and FRx).

[0226] - When some fields of the UE-MRDC-Capability have different values for FDD and TDD (if (some) UE capability fields have different values for FDD and TDD),

[0227] ◇ In the case of FDD, when the UE 1f-01 must support additional capabilities, compared with the setting of the previous fields of the UE-MRDC-Capability (if for FDD, the UE supports additional capabilities compared with the capabilities indicated by the previous fields of the UE-MRDC-Capability),

[0228] · The UE 1f-01 may include an fdd-Add-UE-MRDC-Capabilities field in the UE-MRDC-Capability, and may set the fdd-Add-UE-MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FDD are reflected (including the fdd-Add-UE-MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to FDD).

[0229] ◇ In the case of TDD, when the UE 1f-01 has to support additional capabilities, compared with the setting of the previous field of the UE-MRDC-Capability (if for TDD, the UE supports additional capabilities compared with the capabilities indicated by the previous field of the UE-MRDC-Capability).

[0230] · The UE 1f-01 may include a tdd-Add-UE-MRDC-Capabilities field in the UE-MRDC-Capability, and may set the tdd-Add-UE-MRDC-Capabilities field to include a field value on which other additional capabilities applicable to TDD are reflected (including the tdd-Add-UE-MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to TDD).

[0231] * When the UE 1f-01 supports one of FDD and TDD (in the present disclosure, xDD is used to indicate one of FDD and TDD), and supports both FR1 and FR2 (otherwise if the UE supports a single xDD mode and both FR1 and FR2).

[0232] - UE 1f-01 can set all fields of UE-MRDC-Capability except fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to xDD, FR1, and FR2 (Set all fields of UE-MRDC-Capability except fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to xDD, FR1, and FR2).

[0233] - When some fields of UE-MRDC-Capability have different values for FR1 and FR2 (If (some) UE capability fields have different values for FR1 and FR2),

[0234] *227 ◇ In the case of FR1, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-MRDC-Capability (If for FR1, the UE supports additional functions compared with the functions indicated by the previous fields of UE-MRDC-Capability),

[0235] · UE 1f-01 can include the fr1-Add-UE-MRDC-Capabilities field in UE-MRDC-Capability and can set the fr1-Add-UE-MRDC-Capabilities field to include field values on which other additional functions applicable to FR1 are reflected. (Include the field fr1-Add-UE-MRDC-Capabilities and set it to include the field reflecting the additional functions applicable to FR1).

[0236] ◇ In the case of FR2, when UE 1f-01 must support additional functions, compared with the setting of the previous fields of UE-MRDC-Capability (If for FR2, the UE supports additional functions compared with the functions indicated by the previous fields of UE-MRDC-Capability),

[0237] · The UE 1f-01 may include a fr2-Add-UE-MRDC-Capabilities field in the UE-MRDC-Capability, and may set the fr2-Add-UE-MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR2 are reflected. (Include the fr2-Add-UE-MRDC-Capabilities field and set it to include a field reflecting additional capabilities applicable to FR2).

[0238] * When the UE 1f-01 supports one of FDD and TDD and supports one of FR1 and FR2 (otherwise if the UE supports a single xDD mode and a single FRx),

[0239] - The UE 1f-01 may set all fields of the UE-MRDC-Capability other than fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to xDD and FRx (Set all fields of the UE-MRDC-Capability other than fdd-Add-UE-MRDC-Capabilities, tdd-Add-UE-MRDC-Capabilities, fr1-Add-UE-MRDC-Capabilities, and fr2-Add-UE-MRDC-Capabilities to include values applicable to xDD, FRx).

[0240] 2> The UE 1f-01 may include a supported MRDC band combination in the supportedBandCombination.

[0241] 1> The UE 1f-01 sends a UECapabilityInformation message to the lower layer to send the UECapabilityInformation message.

[0242] The UE-NR-Capability described above is shown as 1f-03 in Figure 1Fb and the UE-MRDC-Capability described above is in Figure 1Fcis shown as 1f-04 in the figure, and information about all parameters can be referenced in "38.331: Radio Resource Control (RRC) Protocol Specification", which is a 3GPP standard specification. In an embodiment of the present disclosure, the process of sending the UECapabilityInformation message can be summarized as follows.

[0243] UE-NR / MRDC-Capability and xxx-Add-UE-NR / MRDC-Capabilities can respectively indicate UE-NR-Capability and / or UE-MRDC-Capability and xxx-Add-UE-NR-Capabilities and / or xxx-Add-UE-MRDC-Capabilities. (UE-NR / MRDC-Capability and xxx-Add-UE-NR / MRDC-Capabilities respectively mean UE-NR-Capability and / or UE-MRDC-Capability and xxx-Add-UE-NR-Capabilities and / or xxx-Add-UE-MRDC-Capabilities.)

[0244] 1> When UE 1f-01 supports all of FDD, TDD, FR1, and FR2 (if the UE supports both FDD and TDD and both FR1 and FR2):

[0245] 2> UE 1f-01 can set all fields of UE-NR / MRDC-Capability except for fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to FDD, TDD, FR1, and FR2 (set all fields of UE-NR / MRDC-Capabilities except for fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to FDD, TDD, FR1, and FR2);

[0246] 2> When the UE capability fields have different values for FDD and TDD (if (some) UE capability fields have different values for FDD and TDD):

[0247] 3> In the case of FDD, when UE 1f-01 supports additional capabilities, compared to the setting of the previous field of UE-NR / MRDC-Capability (if for FDD, the UE supports additional capabilities compared to the capabilities indicated by the previous field of UE-NR / MRDC-Capability):

[0248] 4> UE 1f-01 may include the fdd-Add-UE-NR / MRDC-Capabilities field and may set the fdd-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FDD are reflected (including the field fdd-Add-UE-NR / MRDC-Capabilities and setting it to include a field reflecting additional capabilities applicable to FDD);

[0249] 3> In the case of TDD, when UE 1f-01 supports additional capabilities, compared to the setting of the previous field of UE-NR / MRDC-Capability (if for TDD, the UE supports additional capabilities compared to the capabilities indicated by the previous field of UE-NR / MRDC-Capability):

[0250] 4> UE 1f-01 may include the tdd-Add-UE-NR / MRDC-Capabilities field and may set the tdd-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to TDD are reflected (including the field tdd-Add-UE-NR / MRDC-Capabilities and setting it to include a field reflecting additional capabilities applicable to TDD);

[0251] 2> When the UE capability fields have different values for FR1 and FR2 (if (some) UE capability fields have different values for FR1 and FR2):

[0252] 3> In the case of FR1, when UE 1f-01 supports additional capabilities, compared to the setting of the previous field of UE-NR / MRDC-Capability (if for FR1, the UE supports additional capabilities compared to the capabilities indicated by the previous field of UE-NR / MRDC-Capability):

[0253] 4>UE 1f-01 may include a fr1-Add-UE-NR / MRDC-Capabilities field and may set the fr1-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR1 are reflected (including the fr1-Add-UE-NR / MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to FR1);

[0254] 3>In the case of FR2, when UE 1f-01 supports additional capabilities, compared with the setting of the previous field of UE-NR / MRDC-Capability (if for FR2, the UE supports additional capabilities compared with the capabilities indicated by the previous field of UE-NR / MRDC-Capability):

[0255] 4>UE 1f-01 may include a fr2-Add-UE-NR / MRDC-Capabilities field and may set the fr2-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR2 are reflected (including the fr2-Add-UE-NR / MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to FR2);

[0256] 1>When UE 1f-01 supports both FDD and TDD and supports a single FRx

[0257] (if the UE supports both FDD and TDD and a single FRx):

[0258] 2>UE 1f-01 can set all fields of UE-NR / MRDC-Capability except fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to FDD, TDD, and FRx (set all fields of UE-NR / MRDC-Capability except fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to FDD, TDD, and FRx);

[0259] 2>When the UE capability fields have different values for FDD and TDD (if (some) UE capability fields have different values for FDD and TDD):

[0260] 3>In the case of FDD, when UE 1f-01 supports additional functions, compared with the setting of the previous fields of UE-NR / MRDC-Capability (if for FDD, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR / MRDC-Capability):

[0261] 4>UE 1f-01 can include the fdd-Add-UE-NR / MRDC-Capabilities field and can set the fdd-Add-UE-NR / MRDC-Capabilities field to include field values on which other additional functions applicable to FDD are reflected (include the field fdd-Add-UE-NR / MRDC-Capabilities and set it to include the field reflecting the additional functions applicable to FDD);

[0262] 3>In the case of TDD, when UE 1f-01 supports additional functions, compared with the setting of the previous fields of UE-NR / MRDC-Capability (if for TDD, the UE supports additional functions compared with the functions indicated by the previous fields of UE-NR / MRDC-Capability):

[0263] 4> The UE 1f-01 may include a tdd-Add-UE-NR / MRDC-Capabilities field and may set the tdd-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to TDD are reflected (including the field tdd-Add-UE-NR / MRDC-Capabilities and setting it to include a field reflecting additional capabilities applicable to TDD);

[0264] 1> When the UE 1f-01 supports a single xDD mode and supports both FR1 and FR2

[0265] (if the UE supports a single xDD mode as well as both FR1 and FR2):

[0266] 2> The UE 1f-01 may set all fields of UE-NR / MRDC-Capability other than fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to the xDD mode, FR1, and FR2 (set all fields of UE-NR / MRDC-Capabilities other than fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to the xDD mode, FR1, and FR2);

[0267] 2> When the UE capability fields have different values for FR1 and FR2 (if (some) UE capability fields have different values for FR1 and FR2):

[0268] 3> In the case of FR1, when the UE 1f-01 supports additional capabilities, compared with the setting of the previous fields of UE-NR / MRDC-Capability (if for FR1, the UE supports additional capabilities compared with the capabilities indicated by the previous fields of UE-NR / MRDC-Capability):

[0269] 4> UE 1f-01 may include a fr1-Add-UE-NR / MRDC-Capabilities field and may set the fr1-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR1 are reflected (including the fr1-Add-UE-NR / MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to FR1);

[0270] 3> In the case of FR2, when UE 1f-01 supports additional capabilities, compared to the setting of the previous field of UE-NR / MRDC-Capability (if for FR2, the UE supports additional capabilities compared to the capabilities indicated by the previous field of UE-NR / MRDC-Capability):

[0271] 4> UE 1f-01 may include a fr2-Add-UE-NR / MRDC-Capabilities field and may set the fr2-Add-UE-NR / MRDC-Capabilities field to include a field value on which other additional capabilities applicable to FR2 are reflected (including the fr2-Add-UE-NR / MRDC-Capabilities field and setting it to include a field reflecting additional capabilities applicable to FR2);

[0272] 1> When UE 1f-01 supports a single xDD mode and supports a single FRx

[0273] (if the UE supports a single xDD mode and a single FRx):

[0274] UE 1f-01 can set all fields of UE-NR / MRDC-Capability except fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to the xDD mode and FRx (set all fields of UE-NR / MRDC-Capability except fdd-Add-UE-NR / MRDC-Capabilities, tdd-Add-UE-NR / MRDC-Capabilities, fr1-Add-UE-NR / MRDC-Capabilities, and fr2-Add-UE-NR / MRDC-Capabilities to include values applicable to the xDD mode and FRx).

[0275] Figure 2A A diagram is shown for describing a method of transmitting and receiving messages between UE2a-01 and gNB2a-03 to send a scheduling request according to an embodiment of the present disclosure.

[0276] Reference Figure 2A , the UE 2a-01 in the idle mode (RRC_IDLE) can perform access (2a-11) to the gNB 2a-03 due to the appearance of data to be transmitted. The idle mode means a state where the UE 2a-01 is not connected to the network to save the power of the UE 2a-01 and thus cannot transmit data. For data transmission, the UE 2a-01 must transition to the connected mode (RRC_CONNECTED). When the UE 2a-01 is successful in the process of accessing the gNB 2a-03, the UE 2a-01 transitions to the connected mode (RRC_CONNECTED). The UE 2a-01 in the connected mode can be enabled to send data to and receive data from the gNB 2a-03 by performing security activation and bearer configuration on the data (to be described below).

[0277] After that, gNB 2a-03 may configure radio bearers for data transmission (Data Radio Bearers (DRBs)), and may send SR resources and related configuration information for requesting UL resources (2a-13). A DRB indicates the logical channel / path via which wireless data is sent. For example, when each logical channel identifier mapped to each DRB is marked on the sub-header of the MAC layer, each data packet is sent such that UE 2a-01 can identify which logical channel / path the corresponding packet belongs to. In addition, as described above, the SR resource is information to be sent via the PUCCH, and gNB 2a-03 may set multiple periodic SR resources for UE 2a-01. In the current embodiment of the present disclosure, a regular buffer status report (regular BSR) triggers the SR, and the SR to be sent may be determined based on the content (LCH) reported in the regular BSR. Therefore, when configuring each SR, a (plural) specific logical channel may also be configured together with each SR.

[0278] According to the following various conditions, UE 2a-01 may trigger the current BSR of UE 2a-01, and the BSR may be classified based on the conditions for triggering the transmission.

[0279] - Type 1: Regular BSR

[0280] When UE 2a-01 has data that can be sent relative to a certain logical channel / radio bearer (RB) belonging to a logical channel group (LCG), the BSR is sent when the BSR retransmission timer (retxBSR-Timer) expires.

[0281] When data to be sent relative to a certain logical channel / RB belonging to an LCG is generated in the upper layer (RLC layer or PDCP layer), and the data has a higher priority than the highest priority of any logical channel / RB belonging to any LCG, the BSR is sent.

[0282] When data to be sent relative to a certain logical channel / RB belonging to an LCG is generated in the upper layer (RLC layer or PDCP layer), and there is no data in any LCG except for this data, the BSR is sent.

[0283] - Type 2: Periodic BSR

[0284] When the periodic BSR timer configured for UE 2a-01 expires, the BSR is sent.

[0285] - Type 3: Padding BSR

[0286] When the padding bits used to fill the unused space that appears after data transmission are equal to or greater than the sum of the size of the BSR MAC control element (CE) and the size of the sub-header of the BSR MAC CE after UL resources are allocated, transmit the BSR.

[0287] When a packet exists in the buffers of multiple LCGs, transmit a truncated BSR.

[0288] As described above, when generating a regular BSR according to the foregoing conditions, UE 2a-01 can trigger the transmission of an SR through a first SR resource and then can transmit the SR. Therefore, in the current embodiment of the present disclosure, when triggering a regular BSR through an LCH and an SR configuration mapped to the LCH, UE 2a-01 triggers the SR. When the SR is triggered, the SR may be considered pending until the SR is cancelled. The SR can be cancelled when the BSR MAC CE (i.e., the control message of the MAC layer) of all buffer states including the BSR that triggers the SR is sent to gNB 2a-03. The BSR MAC CE is a control message of the MAC layer, and UE 2a-01 reports the buffer state by using the BSR MAC CE, and the buffer state includes data to be sent to gNB 2a-03 via the UL. For example, it can be assumed that in such a scenario, gNB 2a-03 configures three SRs for UE 2a-01, and SR#1 is mapped to LCH x and LCH y, and SR#2 is mapped to LCH z. Assuming that LCH x, LCH y, and LCH z have the first, second, and third priorities respectively, when traffic only exists in LCH z in the buffer (and then data appears in LCHy, triggering a regular BSR due to LCH y, SR#1 can be triggered.

[0289] The RRC configuration message may include information about at least one of the time / frequency / code / parameter set (subcarrier spacing) / transmission time interval (TTI) length of SR transmission according to each SR resource, and information about the LCH mapped to each SR resource.

[0290] gNB 2a-03 can send various measurement configurations to UE 2a-01 by using the RRCReconfiguration message of the RRC layer. After that, UE 2a-01 sends an acknowledgement message (2a-15) about the configuration, and for this purpose, the RRCReconfigurationComplete message of the RRC layer can be used.

[0291] As described above, it is possible to assume a scenario in which gNB 2a-03 configures three SRs for UE 2a-01, and SR#1 is mapped to LCH x and LCH y, and SR#2 is mapped to LCH z. In this regard, it is assumed that LCH x, LCH y, and LCH z have first, second, and third priorities, respectively.

[0292] After that, when traffic exists only in LCH z in the buffer, and then data appears in LCH y, a regular BSR (2a-17) is triggered due to LCH y, and thus a pending SR (2a-19) may occur with respect to SR#1.

[0293] Therefore, when, according to each SR configuration associated with the (multiple) pending SRs, each sr-ProhibitTimer set for each SR configuration is not running, UE 2a-01 can send an SR (2a-21) to gNB 2a-03 via the PUCCH resource configured for each SR configuration, and can start the sr-ProhibitTimer set for the corresponding SR configuration. When there is no SR associated with the pending SR, UE 2a-01 can perform random access to directly send a preamble to gNB 2a-03.

[0294] In the foregoing example, after that, when new data is generated in LCH x, a regular BSR (2a-27) is triggered due to LCH x, and thus an additional pending SR (2a-29) may occur with respect to SR#1. That is, there may be two pending SRs with respect to SR#1.

[0295] However, since the sr-ProhibitTimer with respect to SR#1 is already running, UE 2a-01 may not send an SR (2a-25) until the sr-ProhibitTimer with respect to SR#1 expires.

[0296] UE 2a-01 checks the following conditions for each SR configuration. That is, in the current embodiment of the present disclosure, the two pending SRs belong to one SR#1, and thus UE 2a-01 can perform the following operations only once, rather than twice.

[0297] - The case where UE 2a-01 is checking whether there is a PUCCH resource in the corresponding SR configuration.

[0298] - The case where the sr-ProhibitTimer set for the corresponding SR configuration is not running.

[0299] * The case where the PUCCH resource of the 292-SR configuration does not overlap with the measurement gap for measurement of an adjacent cell.

[0300] - The case where the PUCCH resources configured for SR do not overlap with the resources for data transmission.

[0301] When all the foregoing conditions are met, UE 2a-01 may increment SR_COUNTER by 1, may instruct the physical layer to send the PUCCH resources, and thus may send an SR (2a-31), and then may restart sr-ProhibitTimer.

[0302] After that, when UL resources are allocated from gNB 2a-03 (2a-33), UE 2a-01 may send a BSR MAC CE (2a-35) through the corresponding resources. When the BSR MAC CE includes all the buffer states when the second regular BSR is triggered, UE 2a-01 may cancel all two pending SRs. However, when the BSR MAC CE includes only the buffer states when the first regular BSR is triggered, UE 2a-01 may cancel only SR#1 without canceling SR#2 and leave SR#2 pending. By doing so, when sr-ProhibitTimer expires later, UE 2a-01 may additionally send an SR.

[0303] Figure 2B A flowchart is shown for describing the operation of a UE when sending a scheduling request according to an embodiment of the present disclosure.

[0304] In Figure 2B , it is assumed that the UE is connected to an LTE BS and is thus in the RRC_CONNECTED state (2b-01). After that, the UE may be configured for a DRB from the BS, may be configured for SR resources and related configuration information for requesting UL resources from the BS, and may send an acknowledgment message in response to the configuration (2b-03).

[0305] As described above, according to various conditions below, the UE may trigger the UE's current BSR, and the BSR may be classified based on the conditions for triggering the transmission.

[0306] - Type 1: Regular BSR

[0307] Condition 1: When UE 2a-01 has data that can be sent relative to a certain logical channel / RB belonging to an LCG, and in the case where the BSR retransmission timer expires, send the BSR.

[0308] Condition 2: When data to be sent relative to a certain logical channel / RB belonging to an LCG is generated in the upper layer (RLC layer or PDCP layer), and the data has a higher priority than the highest priority of the logical channels / RBs belonging to any LCG, send the BSR.

[0309] Condition 3: The BSR is sent when data to be sent relative to a certain logical channel / RB belonging to an LCG is generated in the upper layer (RLC layer or PDCP layer), and no LCG has data other than this data.

[0310] - Type 2: Periodic BSR

[0311] The BSR is sent when the periodic BSR timer configured for UE 2c-01 expires.

[0312] - Type 3: Padding BSR

[0313] The BSR is sent when, after UL resources are allocated, the padding bits used to fill the unused space that appears after data transmission are equal to or greater than the sum of the size of the BSR MAC CE and the size of the sub-header of the BSR MAC CE.

[0314] When packets exist in the buffers of multiple LCGs, a truncated BSR is sent.

[0315] At this time, the UE can determine whether a regular BSR is triggered because traffic appears in the logical channels configured from all logical channels (or when the traffic remains unchanged when the retxBSR-Timer expires) (2b-05).

[0316] When a regular BSR is triggered, the UE can trigger an SR and can determine whether a configured PUCCH SR resource exists in the triggered SR (2b-07). When the configured PUCCH SR resource does not exist in the triggered SR, the UE can perform random access and then can send a BSR MAC CE (2b-15).

[0317] When the configured PUCCH SR resource exists in the triggered SR (i.e., when the SR configuration mapped to the triggered and then pending SR exists), the UE can check the following conditions for each SR configuration. That is, in the current embodiment of the present disclosure, two pending SRs belong to an SR#1, so the following operations can be performed only once instead of twice.

[0318] - Check whether there is a situation where a PUCCH resource exists in the corresponding SR configuration.

[0319] - The situation where the sr-ProhibitTimer set for the corresponding SR configuration is not running.

[0320] - The situation where the PUCCH resource of the SR configuration does not overlap with the measurement gap for measurement of adjacent cells.

[0321] - The case where the PUCCH resources configured for SR do not overlap with the resources used for data transmission.

[0322] When all the above conditions are met, the UE can determine whether the number of SR transmissions is less than the maximum number of allowed SR transmissions (sr_TransMax), and when the number of SR transmissions is less than the maximum number of allowed SR transmissions (sr_TransMax), the UE can increment SR_COUNTER by 1, can indicate to the physical layer to send the PUCCH resources to send SR (2b-09), and can restart the sr-ProhibitTimer. When the number of SR transmissions reaches the maximum number of allowed SR transmissions, the UE can perform the following operations.

[0323] - Notify the RRC layer about the release of the PUCCH resources of all serving cells;

[0324] - Notify the RRC layer about the release of the SRS resources of all serving cells;

[0325] - Remove the configured DL allocation and UL allocation information;

[0326] - Release the PUSCH resources used for reporting semi-permanent CSI; and

[0327] - When the SR is sent to the MCG, perform random access on the PCell, and when the SR is sent to the SCG, perform random access on the PSCell, and then cancel all pending SRs.

[0328] After that, the UE can determine whether UL resources are allocated from the BS (2b-11), and when not allocated, the sr-ProhibitTimer does not run, and when the number of SR transmissions has not reached the maximum number of allowed SR transmissions (2b-13), the UE can retransmit the SR (2b-09). When the number of SR transmissions reaches the maximum number of allowed SR transmissions (2b-13), the UE can send the BSR MAC CE by performing random access (2b-15).

[0329] When the UE receives UL resources, the UE can send the BSR MAC CE through the UL resources (2b-17). In addition, when the BSR MAC CE includes all buffer states when the second regular BSR is triggered, the UE can cancel all two pending SRs. However, when the BSR MAC CE only includes the buffer states when the first regular BSR is triggered, the UE can only cancel the first SR, and can not cancel the second SR, and leave the second SR pending. By doing so, when the sr-ProhibitTimer expires thereafter, the UE can additionally send the second SR.

[0330] Figure 3A FIG. shows a diagram for describing DL and UL channel frame structures of beam-based communication performed in an NR system according to an embodiment of the present disclosure.

[0331] Referring Figure 3A , BS 3a-01 may send signals in the form of beams 3a-11, 3a-13, 3a-15, and 3a-17 for wider coverage or strong signaling. Thus, UE 3a-03 in the cell may need to send or receive data by using a specific beam (in Figure 3A , beam #1 3a-13) sent by BS 3a-01.

[0332] According to whether UE 3a-03 is connected to BS 3a-01, UE 3a-03 may be classified as being in RRC idle mode, RRC inactive mode, or RRC connected mode. Thus, when UE 3a-03 is in RRC inactive mode, BS 3a-01 may not know where UE 3a-03 is.

[0333] When UE 3a-03 attempts to transition from RRC inactive mode to RRC connected mode, UE 3a-03 may receive synchronization signal blocks (SSBs) 3a-21, 3a-23, 3a-25, and 3a-27 sent from BS3a-01. The SSB may be an SSB signal periodically sent at a specific interval set by BS 3a-01, and each SSB may include a primary synchronization signal (PSS) 3a-41, a secondary synchronization signal (SSS) 3a-43, and a physical broadcast channel (PBCH) 3a-45.

[0334] Figure 3A The scenario where each beam sends an SSB is assumed in Figure 3ABelow beam #1 3a-13 in, thus, UE 3a-03 receives SSB #1 3a-23 transmitted by beam #1 3a-13. When UE 3a-03 receives SSB #1 3a-23, UE 3a-03 can obtain the physical cell identifier (PCI) of BS 3a-01 from the PSS or SSS, and when UE 3a-03 receives the PBCH, UE 3a-03 can know the identifier of the currently received SSB (e.g., SSB #1), as well as where the SSB is located in the 10 ms frame and which system frame number (SFN) among the SFNs the SSB is located in within the 10.24 ms period.

[0335] In addition, the PBCH may include a master information block (MIB), and the MIB may include information indicating the location of the system information block type 1 (SIB1) that can receive more detailed configuration information of the broadcast cell. When UE 3a-03 receives SIB1, UE 3a-03 can know the total number of SSBs transmitted by BS 3a-01, and the physical random access channel (PRACH) opportunity (e.g., Figure 3A 3a-30 to 3a-39 of, which are allocated at intervals of 1 ms) for performing random access on BS 3a-01 to transition to the RRC connected mode (more specifically, transmitting a preamble as a physical signal designed to be synchronized with UL transmission). In addition, based on the information in SIB1, UE 3a-03 can determine which PRCH opportunity is mapped to which SSB index. For example, in Figure 3A assuming that the PRACH opportunities are allocated at intervals of 1 ms as described above, and 1 / 2 SSB is allocated for each PRACH opportunity (i.e., two PRACHs for each SSB). Therefore, Figure 3A shows a scenario where two PRACH opportunities are allocated for each SSB starting from the PRACH opportunity starting with the SFN. For example, PRACH opportunities 3a-30 and 3a-31 can be allocated for SSB #0, and PRACH opportunities 3a-32 and 3a-33 can be allocated for SSB #1. After configuring the PRACH opportunities for all SSBs, subsequent PRACH opportunities 3a-38 and 3a-39 can be allocated for the first SSB.

[0336] Therefore, the UE 3a-03 can identify the positions of the PRACH opportunities 3a-32 and 3a-33 of SSB#1, and thus can transmit a random access preamble on the earliest PRACH opportunity 3a-32 at the current time point among the PRACH opportunities 3a-32 and 3a-33 corresponding to SSB#1. Since the BS 3a-01 receives the preamble on the PRACH opportunity 3a-32, the BS 3a-01 can determine that the UE 3a-03 has selected SSB#1 and transmitted the preamble, and can transmit or receive data through the beam corresponding to SSB#1 when performing subsequent random access.

[0337] Figure 3B FIG. shows a diagram for describing a cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to an embodiment of the present disclosure.

[0338] The cell reselection process indicates a process in which a UE in RRC idle mode or RRC inactive mode determines whether to maintain the current serving cell or reselect a cell as an adjacent cell when the quality of service of the serving cell deteriorates compared to the quality of service of an adjacent cell due to a predetermined reason or due to the movement of the UE. In handover, whether to perform handover is determined by the network (MME, access and mobility management function (AMF), source eNB or source gNB), while in the cell reselection process, the UE itself can determine whether to perform the cell reselection process based on the measurement values of the UE. The cell to be reselected by the UE when the UE moves can be an intra-frequency cell using the same NR frequency as the serving cell where the UE is currently camped, an inter-frequency cell using a different NR frequency, or an inter-radio access technology (inter-RAT) cell using a different RAT.

[0339] A UE (operation 3b-01) in RRC idle mode or RRC inactive mode can perform a series of operations when it is camped on a serving cell (operation 3b-05).

[0340] In operation 3b-10, a UE in RRC idle mode or RRC inactive mode may receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information may be divided into a master information block (MIB) and system information blocks (SIBs). In addition, the SIBs may be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode may pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a certain serving cell before the UE camps on a certain serving cell. For reference, the MIB and SIB1 may be system information to be commonly applied to all UEs. SIB2 may be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselecting a same-frequency cell, a different-frequency cell, or a different-RAT cell. SIB3, SIB4, and SIB5 may include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0341] SIB1 may include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information may be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 may include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure an adjacent cell signal. Specifically, SIB2 may include common information for reselecting a same-frequency cell, a different-frequency cell, or a different-RAT cell, SIB3 may include information for reselecting only a same-frequency cell, SIB4 may include information for reselecting only a different-frequency cell, and SIB5 may include information for reselecting only a different-RAT cell.

[0342] In operation 3b-15, a UE in RRC idle mode or RRC inactive mode may wake up during a discontinuous reception (DRX) period and may measure a reference signal received power (RSRP) Qrxlevmeas and a reference signal received quality (RSRQ) Qqualmeas (operation 3b-15). The UE may calculate a reception level Srxlev and a reception quality Squal of the serving cell based on the measured values by using parameters received from SIB1. The UE may compare the calculated values with thresholds and then may determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell may be determined by using Equation 1 below.

[0343] <Equation 1>

[0344] Srxlev = Qrxlevmeas - (Qrxlevmin + Qrxlevminoffset) - Pcompensation - Qoffsettemp,

[0345] Squal = Qqualmeas - (Qqualmin + Qqualminoffset) - Qoffsettemp.

[0346] The definitions of the parameters used in Equation 1 can be determined according to the 3GPP standard specification entitled "38.304: User Equipment (UE) Procedures in Idle Mode and RRC Inactive State". Hereinafter, the same definition also applies to the embodiments of the present disclosure to which Equation 1 is applied.

[0347] A UE in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize the consumption of battery power (Operation 3b-20). In this regard, a UE in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of a neighbor cell, and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE currently camps. When the received level Srxlev and received quality Squal of the serving cell measured in Operation 3b-15 are lower than the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), a UE in RRC idle mode or RRC inactive mode may measure co-frequency cells by using the same frequency as the serving cell (Operation 3b-20). That is, the received quality Squal or received level Srxlev of each co-frequency cell using the same frequency as the serving cell can be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0348] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3b-20). The UE can obtain information on the priority from a dedicated RRC message from the BS (e.g., RRCRelease message) or system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Additionally, for an inter-frequency cell with a priority equal to or lower than the frequency of the serving cell, or for an inter-RAT cell with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3b-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighboring inter-frequency cells using a frequency different from that of the serving cell, or measure neighboring inter-RAT cells using an RAT different from that of the serving cell (3b-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0349] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3b-25) based on cell reselection priorities and / or rankings, and based on the measurement values of neighboring cells (obtained in 3b-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection to a frequency / RAT cell with a higher priority precedes reselection to a frequency / RAT cell with a lower priority (if multiple cells with different priorities meet the cell reselection criteria, reselection to a cell of a higher priority RAT / frequency should precede reselection to a cell of a lower priority RAT / frequency). The priority information is included in the system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about priorities included in the RRC Release message can have precedence over the information about priorities included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0350] - First operation:

[0351] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed after the UE camps on the current serving cell, the UE can perform reselection for the inter-frequency or inter-RAT cell when the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0352] - Second operation:

[0353] * When the UE cannot perform the first operation, the UE can perform the second operation.

[0354] * When 1 second has elapsed after the UE camps on the current serving cell and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE can perform reselection for the inter-frequency or inter-RAT cell.

[0355] In this regard, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0356] In addition, the operation of the UE for the rank-based cell reselection evaluation process of the co-frequency cell belonging to the frequency of the current serving cell or the inter-frequency cell having the same priority as the frequency of the current serving cell will now be described below.

[0357] - Third operation:

[0358] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE may derive the rank of each cell based on the measured value of RSRP (the UE shall perform ranking on all cells that meet the cell selection criterion S). The ranks of the serving cell and the neighboring cells can be calculated separately using Equation 2 below.

[0359] <Equation 2>

[0360] Rs = Qmeas,s + Qhyst

[0361] Rn = Qmeas,n - Qoffset

[0362] * In Equation 2, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the neighboring cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the neighboring cell. SIB2 includes the Qhyst value, and the Qhyst value can be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled for each cell, is only applied to the specified cell, and is included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled for each cell, is only applied to the specified cell, and is included in SIB4. When the rank of the neighboring cell derived according to Equation 2 is greater than the rank of the serving cell (i.e., Rn > Rs), the UE may camp on the best cell among the neighboring cells.

[0363] In addition, the operation of the UE for the cell reselection evaluation process of a heterogenous frequency / heterogenous RAT cell with a lower priority than the frequency of the current serving cell will now be described below.

[0364] *357 - Fourth operation:

[0365] *When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the heterogenous frequency or heterogenous RAT cell.

[0366] - Fifth operation:

[0367] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0368] *When 1 second has elapsed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the heterogenous frequency or heterogenous RAT cell.

[0369] In this regard, the fourth or fifth operation of the UE for an inter-frequency cell can be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in the SIB2 broadcast by the serving cell, and the received quality Squal, received level Srxlev of the inter-frequency cell, and the thresholds ThrehX,LowQ and ThreshX,LowP included in the SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for an inter-RAT cell can be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in the SIB2 broadcast by the serving cell, and the received quality Squal, received level Srxlev of the inter-RAT cell, and the thresholds ThreshX,LowQ and ThreshX,LowP included in the SIB5 broadcast by the serving cell. For example, the SIB4 includes a Qqualmin value or a Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell can be derived based on this value.

[0370] In 3b-30, the UE can derive a list of candidate cells and then can select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3b-35, a UE in RRC idle mode or RRC inactive mode can determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell before the UE finally selects the corresponding cell. At this time, the UE performs the following operations.

[0371] When the selected candidate target cell broadcasts the MIB in 3b-35, the UE can attempt to receive the MIB in 3b-40.

[0372] When the UE cannot obtain the MIB, the UE can perform the sixth operation in 3b-45.

[0373] Sixth operation: The UE can consider the cell status of the corresponding cell to be prohibited and can exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or can exclude the prohibited cell as a candidate for cell selection / reselection for up to 300 seconds). When the received quality Squal and / or received level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE can select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE can select another cell on the same frequency).

[0374] When the UE receives the MIB (upon receiving the MIB), the UE may determine whether the corresponding cell satisfies the first condition or the second condition (3b-50) based on the information included in the MIB.

[0375] First condition: When the cellBarred field value included in the received MIB is set to "barred" and / or PDCCH-ConfigSIB1 is not supported.

[0376] Second condition: A condition that does not correspond to the first condition

[0377] Seventh operation: When the first condition is satisfied, in 3b-55, the UE may consider the corresponding cell as a barred cell and may exclude the barred cell from the candidate cell list for cell selection / reselection within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "notAllowed", the UE may not select / reselect (a) cell(s) using the same frequency as the barred cell within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "allowed", when (a) cell(s) satisfies the cell reselection criteria, the UE may select the (a) cell(s), and the (a) cell(s) uses the same frequency as the barred cell.

[0378] Eighth operation: When the second condition is satisfied, in 3b-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the intraFreqReselection field value included in the MIB is set to "notAllowed", the UE may not select / reselect (a) cell(s) using the same frequency as the cell within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "allowed", when (a) cell(s) satisfies the cell reselection criteria, the UE may select the (a) cell(s), and the (a) cell(s) uses the same frequency as the cell.

[0379] When the selected candidate target cell broadcasts SIB1 in 3b-35, the UE may attempt to receive SIB1 in 3b-65.

[0380] When the UE cannot obtain SIB1, the UE may perform the seventh operation described in 3b-55 in 3b-70.

[0381] When the UE receives SIB1 (upon receiving SIB1), the UE may determine whether the corresponding cell satisfies the third condition or the fourth condition (3b-75) based on the information included in SIB1. The third condition and the fourth condition are as follows.

[0382] Third condition: When the UE identifies the FrequencyInfoDL-SIB included in the received SIB1 and does not support the bandwidth of all subcarrier spacings (SCS) in scs-SpecificCarrierList

[0383] Fourth condition: When the UE identifies the FrequencyInfoDL-SIB included in the received SIB1 and supports the bandwidth of at least one SCS in the scs-SpecificCarrierList (if the UE supports the bandwidth of at least one SCS in the scs-SpecificCarrierList in the FrequencyInfoDL-SIB in SIB1)

[0384] Ninth operation: When the third condition is met, in 3b-80, the UE may determine that the corresponding cell is inaccessible or may consider the corresponding cell to be a prohibited cell, and may exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE may not select / reselect a cell(s) using the same frequency as the prohibited cell within 300 seconds.

[0385] Tenth operation: When the fourth condition is met, in 3b-85, the UE may determine that the corresponding cell is accessible. Then, the UE may derive the reception quality Squal and / or the reception level Srxlev of the corresponding cell based on the information included in SIB1 by using equation 1, and when the reception quality Squal and / or the reception level Srxlev satisfies the S criterion (Srxlev>0 and / or Squal>0), the UE may finally reselect the corresponding cell, otherwise, the UE may not finally reselect the corresponding cell.

[0386] Figure 3C A diagram for describing a cell reselection procedure in an RRC idle mode or an RRC inactive mode of a UE based on system information broadcast by a BS according to another embodiment of the present disclosure is shown.

[0387] A UE in RRC idle mode or RRC inactive mode (operation 3c-01) may perform a series of operations while it resides in a serving cell (operation 3c-05).

[0388] In operation 3c-10, a UE in RRC idle mode or RRC inactive mode may receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information may be divided into a master information block (MIB) and system information blocks (SIBs). In addition, the SIBs may be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode may pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a certain serving cell before the UE camps on a certain serving cell. For reference, the MIB and SIB1 may be system information to be commonly applied to all UEs. SIB2 may be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselection of a same-frequency cell, a different-frequency cell, or a different RAT cell. SIB3, SIB4, and SIB5 may include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0389] SIB1 may include information on parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information may be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 may include information on parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure an adjacent cell signal. Specifically, SIB2 may include common information for reselection of a same-frequency cell, a different-frequency cell, or a different RAT cell, SIB3 may include information for reselection of only a same-frequency cell, SIB4 may include information for reselection of only a different-frequency cell, and SIB5 may include information for reselection of only a different RAT cell.

[0390] In operation 3c-15, a UE in RRC idle mode or RRC inactive mode may wake up during a discontinuous reception (DRX) period and may measure a reference signal received power (RSRP) Qrxlevmeas and a reference signal received quality (RSRQ) Qqualmeas (operation 3c-15). The UE may calculate a reception level Srxlev and a reception quality Squal of the serving cell based on the measured values by using parameters received from SIB1. The UE may compare the calculated values with thresholds and then may determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell may be determined by using Equation 1 above.

[0391] A UE in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize battery power consumption (operation 3c-20). In this regard, a UE in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of a neighbor cell and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE is currently camped. When the received level Srxlev and received quality Squal of the serving cell measured in operation 3c-15 are lower than the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), a UE in RRC idle mode or RRC inactive mode may use the same frequency as the serving cell to measure co-frequency cells (operation 3c-20). That is, the received quality Squal or received level Srxlev of each co-frequency cell using the same frequency as the serving cell may be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0392] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3c-20). The UE can obtain information on the priority from a dedicated RRC message from the BS (e.g., an RRCRelease message) or system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Additionally, for an inter-frequency cell with a priority equal to or lower than the frequency of the serving cell, or for an inter-RAT cell with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3c-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighbor inter-frequency cells using a frequency different from that of the serving cell, or measure neighbor inter-RAT cells using an RAT different from that of the serving cell (3c-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0393] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3c-25) based on cell reselection priority and / or ranking, and based on the measurement values of neighboring cells (obtained in 3c-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection to a frequency / RAT cell with a higher priority precedes reselection to a frequency / RAT cell with a lower priority (if multiple cells with different priorities meet the cell reselection criteria, reselection to a cell of a higher priority RAT / frequency should precede reselection to a cell of a lower priority RAT / frequency). The priority information is included in the system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about the priority included in the RRC Release message may have precedence over the information about the priority included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for a heterogenous frequency / heterogenous RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0394] - First operation:

[0395] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed since the UE camped on the current serving cell, the UE may perform reselection for the heterogenous frequency or heterogenous RAT cell when the received quality Squal of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0396] - Second operation:

[0397] * When the UE cannot perform the first operation, the UE may perform the second operation.

[0398] * When 1 second has elapsed since the UE camped on the current serving cell and the received level Srxlev of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE may perform reselection for the heterogenous frequency or heterogenous RAT cell.

[0399] In this regard, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0400] In addition, the operation of the UE for the ranked cell reselection evaluation process for a co-frequency cell belonging to the frequency of the current serving cell or an inter-frequency cell having a priority equal to the frequency of the current serving cell will now be described below.

[0401] - Third operation:

[0402] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE may derive the ranking of each cell based on the measured value of RSRP (the UE shall perform ranking on all cells that satisfy the cell selection criterion S). The rankings of the serving cell and the neighboring cells can be calculated separately by using Equation 2 above.

[0403] In Equation 2 above, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the neighboring cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the neighboring cell. SIB2 includes the Qhyst value, and the Qhyst value can be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled for each cell, applied only to the specified cell, and included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled for each cell, applied only to the specified cell, and included in SIB4. When the ranking of the neighboring cell derived according to Equation 2 is greater than the ranking of the serving cell (i.e., Rn>Rs), the UE may camp on the best cell among the neighboring cells.

[0404] In addition, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell having a lower priority than the frequency of the current serving cell will now be described below.

[0405] * 398 - Fourth operation:

[0406] *When the UE broadcasts SIB2 including the threshold threshServingLowQ and 1 second has elapsed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0407] - Fifth operation:

[0408] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0409] *When 1 second has elapsed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0410] In this regard, the fourth or fifth operation of the UE for the inter-frequency cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-frequency cell, and the thresholds ThrehX,LowQ and ThreshX,LowP included in SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for the inter-RAT cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-RAT cell, and the thresholds ThreshX,LowQ and ThreshX,LowP included in SIB5 broadcast by the serving cell. For example, SIB4 includes the Qqualmin value or the Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell may be derived based on this value.

[0411] In 3c-30, the UE can derive a list of candidate cells and then can select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3c-35, a UE in RRC idle mode or RRC inactive mode can, before finally selecting the corresponding cell, determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell. At this time, the UE performs the following operations.

[0412] When the selected candidate target cell broadcasts the MIB in 3c-35, the UE can attempt to receive the MIB in 3c-40.

[0413] When the UE fails to obtain the MIB, the UE can perform a sixth operation in 3c-45.

[0414] Sixth operation: The UE can consider the cell status of the corresponding cell to be prohibited and can exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or can exclude the prohibited cell as a candidate for cell selection / reselection for up to 300 seconds). When the reception quality Squal and / or reception level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE can select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE can select another cell on the same frequency).

[0415] When the UE receives the MIB (upon receiving the MIB), the UE can determine whether the corresponding cell meets the first condition or the second condition (3c-50) based on the information included in the MIB.

[0416] First condition: When the value of the cellBarred field included in the received MIB is set to "barred" and / or does not support PDCCH-ConfigSIB1.

[0417] Second condition: Conditions other than those corresponding to the first condition

[0418] Seventh operation: When the first condition is satisfied, in 3c-55, the UE may consider the corresponding cell as a prohibited cell and may exclude the prohibited cell from the candidate cell list for cell selection / reselection within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect a (plurality of) cells using the same frequency as the prohibited cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when the (plurality of) cells meet the cell reselection criteria, the UE may select the (plurality of) cells, and the (plurality of) cells use the same frequency as the prohibited cell.

[0419] Eighth operation: When the second condition is satisfied, in 3c-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect a (plurality of) cells using the same frequency as the cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when the (plurality of) cells meet the cell reselection criteria, the UE may select the (plurality of) cells, and the (plurality of) cells use the same frequency as the cell.

[0420] When the selected candidate target cell broadcasts SIB1 in 3c-35, the UE may attempt to receive SIB1 in 3c-65.

[0421] When the UE cannot obtain SIB1, the UE may perform the seventh operation described in 3c-55 in 3c-70.

[0422] When the UE receives SIB1 (upon receiving SIB1), the UE may determine whether the corresponding cell meets the third condition or the fourth condition (3c-75) based on the information included in SIB1. The third condition and the fourth condition are as follows.

[0423] Third condition: When the UE identifies the FrequencyInfoUL-SIB included in the received SIB1 and does not support the bandwidths of all SCSs in the scs-SpecificCarrierList

[0424] Fourth condition: When the UE identifies the FrequencyInfo UL-SIB included in the received SIB1 and supports the bandwidth of at least one SCS in the scs-SpecificCarrierList (if the UE supports the bandwidth of at least one SCS in the scs-SpecificCarrierList in the FrequencyInfo UL-SIB in SIB1)

[0425] Ninth operation: When the third condition is met, in 3c-80, the UE may determine that the corresponding cell is inaccessible or may consider the corresponding cell to be a prohibited cell, and may exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE may not select / reselect a cell(s) using the same frequency as the prohibited cell within 300 seconds.

[0426] Tenth operation: When the fourth condition is met, in 3c-85, the UE may determine that the corresponding cell is accessible. Then, the UE may derive the reception quality Squal and / or reception level Srxlev of the corresponding cell based on the information included in SIB1 by using equation 1, and when the reception quality Squal and / or reception level Srxlev satisfies the S criterion (Srxlev>0 and / or Squal>0), the UE may finally reselect the corresponding cell, otherwise, the UE may not finally reselect the corresponding cell.

[0427] Figure 3D A diagram for describing a cell reselection procedure in an RRC idle mode or an RRC inactive mode of a UE based on system information broadcast by a BS according to another embodiment of the present disclosure is shown.

[0428] A UE in an RRC idle mode or an RRC inactive mode (operation 3d-01) may perform a series of operations while it resides in a serving cell (operation 3d-05).

[0429] In operation 3d-10, a UE in RRC idle mode or RRC inactive mode can receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information can be divided into a Master Information Block (MIB) and System Information Blocks (SIBs). In addition, the SIBs can be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode can pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a certain serving cell before the UE camps on the certain serving cell. For reference, the MIB and SIB1 can be system information to be commonly applied to all UEs. SIB2 can be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselecting a same-frequency cell, an inter-frequency cell, or an inter-RAT cell. SIB3, SIB4, and SIB5 can include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0430] SIB1 can include information on parameters such as the minimum required reception level, the minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information can be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 can include information on parameters such as the minimum required reception level, the minimum required quality level, or a threshold for determining whether to measure the signal of an adjacent cell. Specifically, SIB2 can include common information for reselecting a same-frequency cell, an inter-frequency cell, or an inter-RAT cell, SIB3 can include information for reselecting only a same-frequency cell, SIB4 can include information for reselecting only an inter-frequency cell, and SIB5 can include information for reselecting only an inter-RAT cell.

[0431] In operation 3d-15, a UE in RRC idle mode or RRC inactive mode can wake up during a Discontinuous Reception (DRX) period and can measure the Reference Signal Received Power (RSRP) Qrxlevmeas and the Reference Signal Received Quality (RSRQ) Qqualmeas (operation 3d-15). The UE can calculate the reception level Srxlev and the reception quality Squal of the serving cell based on the measured values by using the parameters received from SIB1. The UE can compare the calculated values with a threshold and then can determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell can be determined by using Equation 1 above.

[0432] A UE in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize battery power consumption (operation 3d-20). In this regard, a UE in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of a neighbor cell, and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE currently camps. When the received level Srxlev and received quality Squal of the serving cell measured in operation 3d-15 are lower than the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), a UE in RRC idle mode or RRC inactive mode may measure a co-frequency cell by using the same frequency as the serving cell (operation 3d-20). That is, the received quality Squal or received level Srxlev of each co-frequency cell using the same frequency as the serving cell may be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0433] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3d-20). The UE can obtain information on the priority from a dedicated RRC message (e.g., RRCRelease message) from the BS or from the system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Additionally, for an inter-frequency cell with a priority equal to or lower than the frequency of the serving cell, or for an inter-RAT cell with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3d-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighbor inter-frequency cells using a frequency different from that of the serving cell, or measure neighbor inter-RAT cells using an RAT different from that of the serving cell (3d-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0434] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3d-25) based on cell reselection priority and / or ranking, and based on the measurement values of neighboring cells (obtained in 3d-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection to a frequency / RAT cell with a higher priority precedes reselection to a frequency / RAT cell with a lower priority (if multiple cells with different priorities meet the cell reselection criteria, reselection to a cell of a higher priority RAT / frequency should precede reselection to a lower priority RAT / frequency). The priority information is included in the system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about priority included in the RRC Release message can have precedence over the information about priority included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for a heterogenous frequency / heterogenous RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0435] - First operation:

[0436] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed after the UE camps on the current serving cell, the UE can perform reselection for the heterogenous frequency or heterogenous RAT cell when the received quality Squal of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0437] - Second operation:

[0438] * When the UE cannot perform the first operation, the UE can perform the second operation.

[0439] * When 1 second has elapsed after the UE camps on the current serving cell and the received level Srxlev of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE can perform reselection for the heterogenous frequency or heterogenous RAT cell.

[0440] In this regard, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0441] In addition, the operation of the UE for the rank-based cell reselection evaluation process of the co-frequency cell belonging to the frequency of the current serving cell or the inter-frequency cell having the same priority as the frequency of the current serving cell will now be described below.

[0442] - Third operation:

[0443] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE may derive the rank of each cell based on the measured value of RSRP (the UE shall perform ranking on all cells that satisfy the cell selection criterion S). The ranks of the serving cell and the neighboring cells may be calculated separately by using the above equation 2.

[0444] In the foregoing equation 2, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the neighboring cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the neighboring cell. SIB2 includes the Qhyst value, and the Qhyst value may be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled according to each cell, is only applied to the specified cell, and is included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled according to each cell, is only applied to the specified cell, and is included in SIB4. When the rank of the neighboring cell derived according to equation 2 is greater than the rank of the serving cell (i.e., Rn>Rs), the UE may camp on the optimal cell among the neighboring cells.

[0445] In addition, the operation of the UE for the cell reselection evaluation process of the inter-frequency / inter-RAT cell having a lower priority than the frequency of the current serving cell will now be described below.

[0446] * 439 - Fourth operation:

[0447] *When the UE broadcasts SIB2 including the threshold threshServingLowQ and 1 second has elapsed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0448] - Fifth operation:

[0449] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0450] *When 1 second has elapsed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0451] In this regard, the fourth or fifth operation of the UE for the inter-frequency cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-frequency cell and the thresholds ThrehX,LowQ and ThreshX,LowP included in SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for the inter-RAT cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-RAT cell and the thresholds ThreshX,LowQ and ThreshX,LowP included in SIB5 broadcast by the serving cell. For example, SIB4 includes the Qqualmin value or the Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell may be derived based on this value.

[0452] In 3d-30, the UE may derive a list of candidate cells, and then may select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3d-35, a UE in RRC idle mode or RRC inactive mode may, before the UE finally selects the corresponding cell, determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell. At this time, the UE performs the following operations.

[0453] When the selected candidate target cell broadcasts the MIB in 3d-35, the UE may attempt to receive the MIB in 3d-40.

[0454] When the UE fails to obtain the MIB, the UE may perform a sixth operation in 3d-45.

[0455] Sixth operation: The UE may consider the cell state of the corresponding cell to be prohibited, and may exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or may exclude the prohibited cell as a candidate for cell selection / reselection within up to 300 seconds). When the reception quality Squal and / or reception level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE may select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE may select another cell on the same frequency).

[0456] When the UE receives the MIB (upon receiving the MIB), the UE may determine whether the corresponding cell meets the first condition or the second condition (3d-50) based on the information included in the MIB.

[0457] First condition: When the value of the cellBarred field included in the received MIB is set to "barred" and / or does not support PDCCH-ConfigSIB1.

[0458] Second condition: Conditions other than those corresponding to the first condition

[0459] Seventh operation: When the first condition is satisfied, in 3d-55, the UE may consider the corresponding cell as a prohibited cell and may exclude the prohibited cell from the list of candidate cells for cell selection / reselection within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "notAllowed", the UE may not select / reselect a (plural) cell using the same frequency as the prohibited cell within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "allowed", when the (plural) cell meets the cell reselection criteria, the UE may select the (plural) cell, and the (plural) cell uses the same frequency as the prohibited cell.

[0460] Eighth operation: When the second condition is satisfied, in 3d-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the intraFreqReselection field value included in the MIB is set to "notAllowed", the UE may not select / reselect a (plural) cell using the same frequency as the cell within 300 seconds. When the intraFreqReselection field value included in the MIB is set to "allowed", when the (plural) cell meets the cell reselection criteria, the UE may select the (plural) cell, and the (plural) cell uses the same frequency as the cell.

[0461] When the selected candidate target cell broadcasts SIB1 in 3d-35, the UE may attempt to receive SIB1 in 3d-65.

[0462] When the UE cannot obtain SIB1, the UE may perform the seventh operation described in 3d-55 in 3d-70.

[0463] When the UE receives SIB1 (when receiving SIB1), the UE may determine whether the corresponding cell meets the third condition or the fourth condition (3d-75) based on the information included in SIB1. The third condition and the fourth condition are as follows.

[0464] Third condition: When the UE identifies all FrequencyInfoUL-SIB and FrequencyInfoDL-SIB included in the received SIB1 and does not support the bandwidths of all SCSs in the scs-SpecificCarrierList

[0465] Fourth condition: When the UE identifies the FrequencyInfoUL-SIB and FrequencyInfoDL-SIB included in the received SIB1 and supports the bandwidth of at least one SCS in the scs-SpecificCarrierList (if the UE supports the bandwidth of at least one SCS in the scs-SpecificCarrierList in the FrequencyInfoUL-SIB in SIB1 and the bandwidth of at least one SCS in the scs-SpecificCarrierList in the FrequencyInfoDL-SIB in SIB1)

[0466] Ninth operation: When the third condition is met, in 3d-80, the UE may determine that the corresponding cell is inaccessible or may consider the corresponding cell to be a prohibited cell, and may exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE may not select / reselect (multiple) cells using the same frequency as the prohibited cell within 300 seconds.

[0467] Tenth operation: When the fourth condition is met, in 3d-85, the UE may determine that the corresponding cell is accessible. Then, the UE may derive the reception quality Squal and / or the reception level Srxlev of the corresponding cell based on the information included in SIB1 by using equation 1, and when the reception quality Squal and / or the reception level Srxlev satisfies the S criterion (Srxlev>0 and / or Squal>0), the UE may eventually reselect the corresponding cell, otherwise, the UE may not eventually reselect the corresponding cell.

[0468] Figure 3E A diagram for describing a cell reselection procedure in an RRC idle mode or an RRC inactive mode of a UE based on system information broadcast by a BS according to another embodiment of the present disclosure is shown.

[0469] The UE in the RRC idle mode or the RRC inactive mode (operation 3e-01) may perform a series of operations while it camps on a serving cell (operation 3e-05).

[0470] In operation 3e-10, a UE in RRC idle mode or RRC inactive mode can receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information can be divided into a master information block (MIB) and system information blocks (SIBs). In addition, the SIBs can be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode can pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a serving cell before the UE camps on a certain serving cell. For reference, the MIB and SIB1 can be system information to be commonly applied to all UEs. SIB2 can be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselecting a same-frequency cell, an inter-frequency cell, or an inter-RAT cell. SIB3, SIB4, and SIB5 can include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0471] SIB1 can include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information can be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 can include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure an adjacent cell signal. Specifically, SIB2 can include common information for reselecting a same-frequency cell, an inter-frequency cell, or an inter-RAT cell, SIB3 can include information for reselecting only a same-frequency cell, SIB4 can include information for reselecting only an inter-frequency cell, and SIB5 can include information for reselecting only an inter-RAT cell.

[0472] In operation 3e-15, a UE in RRC idle mode or RRC inactive mode can wake up during a discontinuous reception (DRX) period and can measure a reference signal received power (RSRP) Qrxlevmeas and a reference signal received quality (RSRQ) Qqualmeas (operation 3e-15). The UE can calculate a reception level Srxlev and a reception quality Squal of the serving cell based on the measured values by using parameters received from SIB1. The UE can compare the calculated values with thresholds and then can determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell can be determined by using Equation 1 above.

[0473] UEs in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize battery power consumption (operation 3e-20). In this regard, UEs in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of the neighbor cell and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE currently camps. When the received level Srxlev and received quality Squal of the serving cell measured in operation 3e-15 are lower than the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), UEs in RRC idle mode or RRC inactive mode may use the same frequency as the serving cell to measure co-frequency cells (operation 3e-20). That is, the received quality Squal or received level Srxlev of each co-frequency cell using the same frequency as the serving cell may be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0474] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3e-20). The UE can obtain information on the priority from a dedicated RRC message (e.g., RRCRelease message) from the BS or from system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Additionally, for an inter-frequency cell with a priority equal to or lower than the frequency of the serving cell, or for an inter-RAT cell with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3e-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighbor inter-frequency cells using a frequency different from that of the serving cell, or measure neighbor inter-RAT cells using a RAT different from that of the serving cell (3e-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0475] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3e-25) based on cell reselection priorities and / or rankings, and based on the measurement values of neighboring cells (obtained in 3e-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection to a frequency / RAT cell with a higher priority precedes reselection to a frequency / RAT cell with a lower priority (if multiple cells with different priorities meet the cell reselection criteria, reselection to a cell of a higher priority RAT / frequency should precede reselection to a lower priority RAT / frequency). The priority information is included in the system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about priorities included in the RRC Release message can have precedence over the information about priorities included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for a heterogenous frequency / heterogenous RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0476] - First operation:

[0477] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed after the UE camps on the current serving cell, the UE can perform reselection for the heterogenous frequency or heterogenous RAT cell when the received quality Squal of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0478] - Second operation:

[0479] * When the UE cannot perform the first operation, the UE can perform the second operation.

[0480] * When 1 second has elapsed after the UE camps on the current serving cell and the received level Srxlev of the heterogenous frequency or heterogenous RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE can perform reselection for the heterogenous frequency or heterogenous RAT cell.

[0481] In this regard, the UE can perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE can perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0482] In addition, the operation of the UE for the ranked cell reselection evaluation process for a co-frequency cell belonging to the frequency of the current serving cell or an inter-frequency cell having a priority equal to the frequency of the current serving cell will now be described below.

[0483] - Third operation:

[0484] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE can derive the ranking of each cell based on the measured value of RSRP (the UE shall perform ranking on all cells that meet the cell selection criterion S). The rankings of the serving cell and adjacent cells can be calculated separately by using Equation 2 above.

[0485] In the foregoing Equation 2, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the adjacent cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the adjacent cell. SIB2 includes the Qhyst value, and the Qhyst value can be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled per cell, applied only to the specified cell, and included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled per cell, applied only to the specified cell, and included in SIB4. When the ranking of the adjacent cell derived according to Equation 2 is greater than the ranking of the serving cell (i.e., Rn>Rs), the UE can camp on the best cell among the adjacent cells.

[0486] In addition, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell having a lower priority than the frequency of the current serving cell will now be described below.

[0487] * 480 - Fourth operation:

[0488] *When broadcasting SIB2 including the threshold threshServingLowQ and 1 second has passed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0489] - The fifth operation:

[0490] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0491] *When 1 second has passed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0492] In this regard, the fourth or fifth operation of the UE for the inter-frequency cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-frequency cell and the thresholds ThrehX,LowQ and ThreshX,LowP included in SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for the inter-RAT cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-RAT cell and the thresholds ThreshX,LowQ and ThreshX,LowP included in SIB5 broadcast by the serving cell. For example, SIB4 includes the Qqualmin value or Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell may be derived based on this value.

[0493] In 3e-30, the UE can derive a list of candidate cells and then can select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3e-35, a UE in RRC idle mode or RRC inactive mode can, before the UE finally selects the corresponding cell, determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell. At this time, the UE performs the following operations.

[0494] When the selected candidate target cell broadcasts the MIB in 3e-35, the UE can attempt to receive the MIB in 3e-40.

[0495] When the UE cannot obtain the MIB, the UE can perform the sixth operation in 3e-45.

[0496] Sixth operation: The UE can consider the cell status of the corresponding cell to be prohibited and can exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or can exclude the prohibited cell as a candidate for cell selection / reselection for up to 300 seconds). When the reception quality Squal and / or reception level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE can select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE can select another cell on the same frequency).

[0497] When the UE receives the MIB (when receiving the MIB), the UE can determine whether the corresponding cell meets the first condition or the second condition (3e-50) based on the information included in the MIB.

[0498] First condition: When the value of the cellBarred field included in the received MIB is set to "barred" and / or does not support PDCCH-ConfigSIB1.

[0499] Second condition: Conditions that do not correspond to the first condition

[0500] Seventh operation: When the first condition is met, in 3e-55, the UE may consider the corresponding cell as a prohibited cell and may exclude the prohibited cell from the candidate cell list for cell selection / reselection within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (a) cell(s) using the same frequency as the prohibited cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when (a) cell(s) meets the cell reselection criteria, the UE may select the (a) cell(s), and the (a) cell(s) uses the same frequency as the prohibited cell.

[0501] Eighth operation: When the second condition is met, in 3e-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (a) cell(s) using the same frequency as the cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when (a) cell(s) meets the cell reselection criteria, the UE may select the (a) cell(s), and the (a) cell(s) uses the same frequency as the cell.

[0502] When the selected candidate target cell broadcasts SIB1 in 3e-35, the UE may attempt to receive SIB1 in 3e-65.

[0503] When the UE fails to obtain SIB1, the UE may perform the seventh operation described in 3e-55 in 3e-70.

[0504] When the UE receives SIB1 (upon receiving SIB1), the UE may determine whether the corresponding cell meets the third condition or the fourth condition (3e-75) based on the information included in the MIB and SIB1. The third condition and the fourth condition are as follows.

[0505] Third condition: When the UE identifies the SCS value configured in subCarrierSpacingCommon of the received MIB and does not support the bandwidth of the initial DLBWP using the SCS value in locationAndBandwidth configured in the received SIB1

[0506] Fourth condition: When the UE identifies the SCS value configured in subCarrierSpacingCommon of the received MIB and supports the bandwidth of the initial DLBWP using the SCS value in the configured locationAndBandwidth in the received SIB1 (if the UE supports the bandwidth of the initial DLBWP in locationAndBandwidth in SIB1)

[0507] Ninth operation: When the third condition is met, in 3e-80, the UE may determine that the corresponding cell is inaccessible or may consider the corresponding cell to be a prohibited cell, and may exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE may not select / reselect a cell (or cells) using the same frequency as the prohibited cell within 300 seconds.

[0508] Tenth operation: When the fourth condition is met, in 3e-85, the UE may determine that the corresponding cell is accessible. Then, the UE may derive the reception quality Squal and / or the reception level Srxlev of the corresponding cell based on the information included in SIB1 by using equation 1, and when the reception quality Squal and / or the reception level Srxlev satisfies the S criterion (Srxlev>0 and / or Squal>0), the UE may finally reselect the corresponding cell, otherwise, the UE may not finally reselect the corresponding cell.

[0509] Figure 3F A diagram for describing a cell reselection procedure in an RRC idle mode or an RRC inactive mode of a UE based on system information broadcast by a BS according to another embodiment of the present disclosure is shown.

[0510] A UE in RRC idle mode or RRC inactive mode (operation 3f-01) may perform a series of operations while it resides in a serving cell (operation 3f-05).

[0511] In operation 3f-10, a UE in RRC idle mode or RRC inactive mode can receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information can be divided into a master information block (MIB) and system information blocks (SIBs). In addition, the SIBs can be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode can pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a certain serving cell before the UE camps on a certain serving cell. For reference, the MIB and SIB1 can be system information to be commonly applied to all UEs. SIB2 can be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselection of a same-frequency cell, a different-frequency cell, or a different-RAT cell. SIB3, SIB4, and SIB5 can include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0512] SIB1 can include information on parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information can be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 can include information on parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure an adjacent cell signal. Specifically, SIB2 can include common information for reselection of a same-frequency cell, a different-frequency cell, or a different-RAT cell, SIB3 can include information for reselection of only a same-frequency cell, SIB4 can include information for reselection of only a different-frequency cell, and SIB5 can include information for reselection of only a different-RAT cell.

[0513] In operation 3f-15, a UE in RRC idle mode or RRC inactive mode can wake up during a discontinuous reception (DRX) period and can measure a reference signal received power (RSRP) Qrxlevmeas and a reference signal received quality (RSRQ) Qqualmeas (operation 3f-15). The UE can calculate a reception level Srxlev and a reception quality Squal of the serving cell based on the measured values by using parameters received from SIB1. The UE can compare the calculated values with thresholds and then can determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell can be determined by using Equation 1 above.

[0514] UEs in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize battery power consumption (operation 3f-20). In this regard, UEs in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of the neighbor cell, and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE is currently camped. When the received level Srxlev and received quality Squal of the serving cell measured in operation 3f-15 are below the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), UEs in RRC idle mode or RRC inactive mode may use the same frequency as the serving cell to measure co-frequency cells (operation 3f-20). That is, the received quality Squal or received level Srxlev of each co-frequency cell using the same frequency as the serving cell may be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0515] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3f-20). The UE can obtain information on the priority from a dedicated RRC message from the BS (e.g., an RRCRelease message) or system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Furthermore, for an inter-frequency cell with a priority equal to or lower than the frequency of the serving cell, or for an inter-RAT cell with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3f-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighbor inter-frequency cells using a frequency different from that of the serving cell, or measure neighbor inter-RAT cells using an RAT different from that of the serving cell (3f-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0516] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3f-25) based on cell reselection priorities and / or rankings, and based on the measured values of neighboring cells (obtained in 3f-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection to a frequency / RAT cell with a higher priority takes precedence over reselection to a frequency / RAT cell with a lower priority (if multiple cells with different priorities meet the cell reselection criteria, reselection to a cell of a higher priority RAT / frequency should take precedence over a lower priority RAT / frequency). The priority information is included in the system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about priorities included in the RRC Release message can have precedence over the information about priorities included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0517] - First operation:

[0518] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed after the UE camps on the current serving cell, the UE can perform reselection for the inter-frequency or inter-RAT cell when the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0519] - Second operation:

[0520] * When the UE cannot perform the first operation, the UE can perform the second operation.

[0521] * When 1 second has elapsed after the UE camps on the current serving cell and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE can perform reselection for the inter-frequency or inter-RAT cell.

[0522] In this regard, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0523] In addition, the operation of the UE for the ranked cell reselection evaluation process for a co-frequency cell belonging to the frequency of the current serving cell or an inter-frequency cell having a priority equal to the frequency of the current serving cell will now be described below.

[0524] - Third operation:

[0525] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE may derive the rank of each cell based on the measured value of RSRP (the UE shall perform ranking on all cells that satisfy the cell selection criterion S). The ranks of the serving cell and the neighboring cells may be calculated separately by using Equation 2 above.

[0526] In Equation 2 above, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the neighboring cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the neighboring cell. SIB2 includes the Qhyst value, and the Qhyst value may be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled per cell, applied only to the specified cell, and included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled per cell, applied only to the specified cell, and included in SIB4. When the rank of the neighboring cell derived according to Equation 2 is greater than the rank of the serving cell (i.e., Rn>Rs), the UE may camp on the best cell among the neighboring cells.

[0527] In addition, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell having a lower priority than the frequency of the current serving cell will now be described below.

[0528] * 521 - Fourth operation:

[0529] *When broadcasting SIB2 including the threshold threshServingLowQ and 1 second has passed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0530] - Fifth operation:

[0531] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0532] *When 1 second has passed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0533] In this regard, the fourth or fifth operation of the UE for the inter-frequency cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-frequency cell and the thresholds ThrehX,LowQ and ThreshX,LowP included in SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for the inter-RAT cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-RAT cell and the thresholds ThreshX,LowQ and ThreshX,LowP included in SIB5 broadcast by the serving cell. For example, SIB4 includes the Qqualmin value or Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell may be derived based on this value.

[0534] In 3f-30, the UE can derive a list of candidate cells and then can select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3f-35, a UE in RRC idle mode or RRC inactive mode can, before the UE finally selects the corresponding cell, determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell. At this time, the UE performs the following operations.

[0535] When the selected candidate target cell broadcasts the MIB in 3f-35, the UE can attempt to receive the MIB in 3f-40.

[0536] When the UE cannot obtain the MIB, the UE can perform a sixth operation in 3f-45.

[0537] Sixth operation: The UE can consider the cell state of the corresponding cell to be prohibited and can exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or can exclude the prohibited cell as a candidate for cell selection / reselection for up to 300 seconds). When the received quality Squal and / or received level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE can select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE can select another cell on the same frequency).

[0538] When the UE receives the MIB (when receiving the MIB), the UE can determine whether the corresponding cell meets the first condition or the second condition (3f-50) based on the information included in the MIB.

[0539] First condition: When the value of the cellBarred field included in the received MIB is set to "barred" and / or does not support PDCCH-ConfigSIB1.

[0540] Second condition: Conditions that do not correspond to the first condition

[0541] Seventh operation: When the first condition is met, in 3f-55, the UE may consider the corresponding cell as a prohibited cell and may exclude the prohibited cell from the candidate cell list for cell selection / reselection within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (multiple) cells using the same frequency as the prohibited cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when (multiple) cells meet the cell reselection criteria, the UE may select the (multiple) cells, and the (multiple) cells use the same frequency as the prohibited cell.

[0542] Eighth operation: When the second condition is met, in 3f-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (multiple) cells using the same frequency as the cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when (multiple) cells meet the cell reselection criteria, the UE may select the (multiple) cells, and the (multiple) cells use the same frequency as the cell.

[0543] When the selected candidate target cell broadcasts SIB1 in 3f-35, the UE may attempt to receive SIB1 in 3f-65.

[0544] When the UE cannot obtain SIB1, the UE may perform the seventh operation described in 3f-55 in 3f-70.

[0545] When the UE receives SIB1 (upon receiving SIB1), the UE may determine whether the corresponding cell meets the third condition or the fourth condition (3f-75) based on the information included in the MIB and SIB1. The third condition and the fourth condition are as follows.

[0546] Third condition: When the UE identifies the SCS value configured in subCarrierSpacingCommon of the received MIB and does not support the bandwidth of the initial ULBWP using the SCS value in locationAndBandwidth configured in the received SIB1

[0547] Fourth condition: When the UE recognizes the SCS value configured in subCarrierSpacingCommon of the received MIB and supports the bandwidth of the initial UL BWP that uses the SCS value in the configured locationAndBandwidth in the received SIB1 (if the UE supports the bandwidth of the initial UL BWP in locationAndBandwidth in SIB1)

[0548] Ninth operation: When the third condition is satisfied, in 3f-80, the UE may determine that the corresponding cell is not accessible or may consider the corresponding cell as a prohibited cell, and may exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE may not select / reselect (multiple) cells that use the same frequency as the prohibited cell within 300 seconds.

[0549] Tenth operation: When the fourth condition is satisfied, in 3f-85, the UE may determine that the corresponding cell is accessible. Then, the UE may derive the received quality Squal and / or the received level Srxlev of the corresponding cell by using Equation 1 based on the information included in SIB1, and when the received quality Squal and / or the received level Srxlev satisfy the S-criterion (Srxlev > 0 and / or Squal > 0), the UE may finally reselect the corresponding cell; otherwise, the UE may finally not reselect the corresponding cell.

[0550] Figure 3G A diagram is shown for describing the cell reselection process of a UE in RRC idle mode or RRC inactive mode based on system information broadcast by a BS according to another embodiment of the present disclosure.

[0551] A UE (operation 3g-01) in RRC idle mode or RRC inactive mode may perform a series of operations while it is camped on a serving cell (operation 3g-05).

[0552] In operation 3g-10, a UE in RRC idle mode or RRC inactive mode can receive system information broadcast by the BS of the serving cell. In this regard, a UE in RRC idle mode or RRC inactive mode may not receive system information broadcast by the BS of an adjacent cell. The system information can be divided into a master information block (MIB) and system information blocks (SIBs). In addition, the SIBs can be divided into SIB1 and SI messages excluding SIB1 (e.g., SIB2, SIB3, SIB4, SIB5, SIB6, SIB7, SIB8, or SIB9). A UE in RRC idle mode or RRC inactive mode can pre-receive and read system information (e.g., MIB or SIB1) broadcast by the base station of a certain serving cell before the UE camps on a certain serving cell. For reference, the MIB and SIB1 can be system information to be commonly applied to all UEs. SIB2 can be system information to be commonly applied by a UE in RRC idle mode or RRC inactive mode to the process of reselecting a co-frequency cell, an inter-frequency cell, or an inter-RAT cell. SIB3, SIB4, and SIB5 can include information required for a UE in RRC idle mode or RRC inactive mode to reselect a cell.

[0553] SIB1 can include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure the serving cell signal, and such information can be applied in a cell-specific manner. SIB2, SIB3, SIB4, and SIB5 can include information about parameters such as a minimum required reception level, a minimum required quality level, or a threshold for determining whether to measure an adjacent cell signal. Specifically, SIB2 can include common information for reselecting a co-frequency cell, an inter-frequency cell, or an inter-RAT cell, SIB3 can include information for reselecting only a co-frequency cell, SIB4 can include information for reselecting only an inter-frequency cell, and SIB5 can include information for reselecting only an inter-RAT cell.

[0554] In operation 3g-15, a UE in RRC idle mode or RRC inactive mode can wake up during a discontinuous reception (DRX) period and can measure a reference signal received power (RSRP) Qrxlevmeas and a reference signal received quality (RSRQ) Qqualmeas (operation 3g-15). The UE can calculate a reception level Srxlev and a reception quality Squal of the serving cell based on the measured values by using parameters received from SIB1. The UE can compare the calculated values with thresholds and then can determine whether to perform adjacent cell measurements for cell reselection. The reception level Srxlev and the reception quality Squal of the serving cell can be determined by using Equation 1 above.

[0555] UEs in RRC idle mode or RRC inactive mode may not continuously perform neighbor cell measurements, but may determine whether to perform neighbor cell measurements based on measurement rules in order to minimize battery power consumption (operation 3g-20). In this regard, UEs in RRC idle mode or RRC inactive mode may not receive the system information broadcast by the BS of the neighbor cell, and may perform neighbor cell measurements by using the system information broadcast by the serving cell where the UE currently camps. When the received level Srxlev and received quality Squal of the serving cell measured in operation 3g-15 are lower than the thresholds (Srxlev ≤ SintraSearchP and Squal ≤ SIntraSearchQ), UEs in RRC idle mode or RRC inactive mode may measure the same-frequency cells using the same frequency as the serving cell (operation 3g-20). That is, the received quality Squal or received level Srxlev of each same-frequency cell using the same frequency as the serving cell may be derived based on SIB2 or / and SIB3 broadcast by the serving cell (application of Equation 1).

[0556] For reference, information on the thresholds SIntraSearchP and SIntraSearchQ is included in SIB2. Additionally, regardless of the quality of the serving cell, neighbor cell measurements can be performed on inter-frequency and inter-RAT cells with a higher priority than the frequency of the current serving cell (operation 3g-20). The UE can obtain information on the priority from a dedicated RRC message from the BS (e.g., RRCRelease message) or system information. The received quality Squal or received level Srxlev of each inter-frequency cell with a higher priority than the frequency of the serving cell can be derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of each inter-RAT cell with a higher priority than the frequency of the serving cell can be derived based on SIB5 broadcast by the serving cell (according to Equation 1). Additionally, for inter-frequency cells with a priority equal to or lower than the frequency of the serving cell, or for inter-RAT cells with a lower priority than the frequency of the serving cell, when the received level Srxlev and received quality Squal of the serving cell measured in operation 3g-15 are below the thresholds (Srxlex ≤ SnonIntraSearchP and Squal ≤ SintraSearchQ), a UE in RRC idle mode or RRC inactive mode can measure neighbor inter-frequency cells using a frequency different from that of the serving cell, or measure neighbor inter-RAT cells using a RAT different from that of the serving cell (3g-20). That is, the received quality Squal or received level Srxlev of at least one inter-frequency cell with a priority equal to or lower than the frequency of the serving cell is derived based on SIB4 broadcast by the serving cell (according to Equation 1), and the received quality Squal or received level Srxlev of at least one inter-RAT cell with a lower priority than the frequency of the serving cell is derived based on SIB5 broadcast by the serving cell (according to Equation 1). For reference, information on the thresholds SnonIntraSearchP and SnonIntraSearchQ is included in SIB2.

[0557] A UE in RRC idle mode or RRC inactive mode can perform a cell reselection evaluation process (3g-25) based on cell reselection priorities and / or rankings, and based on measurement values of neighboring cells (obtained in 3g-20). That is, when multiple cells that meet the cell reselection criteria have different priorities, reselection of a higher-priority frequency / RAT cell precedes reselection of a lower-priority frequency / RAT cell (if multiple cells with different priorities meet the cell reselection criteria, reselection of a cell with a higher-priority RAT / frequency should precede reselection of a cell with a lower-priority RAT / frequency). Priority information is included in system information (SIB2, SIB4, and SIB5) broadcast by the serving cell, or is included in the RRC Release message received when the UE transitions from RRC connected mode to RRC idle mode or RRC inactive mode. The information about priorities included in the RRC Release message can have precedence over the information about priorities included in the system information broadcast by the serving cell. Now, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell with a higher priority than the frequency of the serving cell will be described below.

[0558] - First operation:

[0559] * When SIB2 including the threshold threshServingLowQ is broadcast and 1 second has elapsed since the UE camped on the current serving cell, the UE can perform reselection for the inter-frequency or inter-RAT cell when the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX).

[0560] - Second operation:

[0561] * When the UE cannot perform the first operation, the UE can perform the second operation.

[0562] * When 1 second has elapsed since the UE camped on the current serving cell and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,HighP), the UE can perform reselection for the inter-frequency or inter-RAT cell.

[0563] In this regard, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-frequency cell, and the value of TreselectionRAT (i.e., the information included in SIB4 broadcast by the serving cell). In addition, the UE may perform a first operation or a second operation based on the received quality Squal, received level Srxlev, thresholds ThrehX,HighQ and ThreshX,HighP of the inter-RAT cell, and the value of TreselectionRAT (i.e., the information included in SIB5 broadcast by the serving cell).

[0564] In addition, the operation of the UE for the rank-based cell reselection evaluation process for a co-frequency cell belonging to the frequency of the current serving cell or an inter-frequency cell having a priority equal to the frequency of the current serving cell will now be described below.

[0565] - Third operation:

[0566] * When the received quality Squal and received level Srxlev of each co-frequency / inter-frequency cell are greater than 0, the UE may derive the rank of each cell based on the measured value of RSRP (the UE shall perform ranking for all cells that satisfy the cell selection criterion S). The ranks of the serving cell and the neighboring cells can be calculated separately by using Equation 2 above.

[0567] In Equation 2 above, Qmeas,s indicates the measured value of RSRP of the serving cell, Qmeas,n indicates the measured value of RSRP of the neighboring cell, Qhyst indicates the hysteresis value of the serving cell, and Qoffset indicates the offset between the serving cell and the neighboring cell. SIB2 includes the Qhyst value, and the Qhyst value can be commonly used for reselection of co-frequency / inter-frequency cells. When reselecting a co-frequency cell, Qoffset is signaled for each cell, is only applied to the specified cell, and is included in SIB3. When reselecting an inter-frequency cell, Qoffset is signaled for each cell, is only applied to the specified cell, and is included in SIB4. When the rank of the neighboring cell derived according to Equation 2 is greater than the rank of the serving cell (i.e., Rn>Rs), the UE may camp on the best cell among the neighboring cells.

[0568] In addition, the operation of the UE for the cell reselection evaluation process for an inter-frequency / inter-RAT cell having a lower priority than the frequency of the current serving cell will now be described below.

[0569] * 562 - Fourth operation:

[0570] *When broadcasting SIB2 including the threshold threshServingLowQ and 1 second has elapsed after the UE camps on the current serving cell, when the received quality Squal of the current serving cell is less than the threshold ThreshServing,LowQ (Squal < ThreshServing,LowQ), and the received quality Squal of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Squal > ThreshX,LowQ), the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0571] - Fifth operation:

[0572] *When the UE cannot perform the fourth operation, the UE may perform the fifth operation.

[0573] *When 1 second has elapsed after the UE camps on the current serving cell, the received level Srxlev of the current serving cell is lower than the threshold ThreshServing,LowP (Srxlev < ThreshServing,LowP), and the received level Srxlev of the inter-frequency or inter-RAT cell is higher than the threshold ThreshX,LowQ during a specific time interval TreselectionRAT (during the time interval TreselectionRAT, Srxlev > ThreshX,LowP), then the UE may perform reselection for the inter-frequency or inter-RAT cell.

[0574] In this regard, the fourth or fifth operation of the UE for the inter-frequency cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-frequency cell and the thresholds ThrehX,LowQ and ThreshX,LowP included in SIB4 broadcast by the serving cell. The fourth or fifth operation of the UE for the inter-RAT cell may be performed based on the thresholds ThreshServing,LowQ and ThreshServing,LowP included in SIB2 broadcast by the serving cell and the received quality Squal, received level Srxlev of the inter-RAT cell and the thresholds ThreshX,LowQ and ThreshX,LowP included in SIB5 broadcast by the serving cell. For example, SIB4 includes the Qqualmin value or the Qrxlevmin value, and the received quality Squal or received level Srxlev of the inter-frequency cell may be derived based on this value.

[0575] In 3G-30, the UE can derive a list of candidate cells and then can select a candidate target cell based on the priority and / or ranking from the list of candidate cells. When selecting a candidate target cell, in 3G-35, a UE in RRC idle mode or RRC inactive mode can, before the UE finally selects the corresponding cell, determine whether to select the corresponding cell by attempting to receive the MIB and SIB1 broadcast by the corresponding cell. At this time, the UE performs the following operations.

[0576] When the selected candidate target cell broadcasts the MIB in 3G-35, the UE can attempt to receive the MIB in 3G-40.

[0577] When the UE fails to obtain the MIB, the UE can perform the sixth operation in 3G-45.

[0578] Sixth operation: The UE can consider the cell status of the corresponding cell to be prohibited and can exclude the corresponding cell from the list of candidate cells for cell selection / reselection within 300 seconds (the UE shall or can exclude the prohibited cell as a candidate for cell selection / reselection for up to 300 seconds). When the reception quality Squal and / or reception level Srxlev of another cell (the other cell uses the same frequency as the corresponding cell) derived according to Equation 1 is greater than 0 and / or meets the cell reselection criteria, the UE can select the other cell (if the selection criteria and / or cell reselection criteria are met, the UE can select another cell on the same frequency).

[0579] When the UE receives the MIB (when receiving the MIB), the UE can determine whether the corresponding cell meets the first condition or the second condition (3G-50) based on the information included in the MIB.

[0580] First condition: When the value of the cellBarred field included in the received MIB is set to "barred" and / or does not support PDCCH-ConfigSIB1.

[0581] Second condition: Conditions other than the first condition

[0582] Seventh operation: When the first condition is met, in 3g-55, the UE may consider the corresponding cell as a prohibited cell and may exclude the prohibited cell from the candidate cell list for cell selection / reselection within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (multiple) cells using the same frequency as the prohibited cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when the (multiple) cells meet the cell reselection criteria, the UE may select the (multiple) cells, and the (multiple) cells use the same frequency as the prohibited cell.

[0583] Eighth operation: When the second condition is met, in 3g-60, the UE may consider the corresponding cell as an allowed cell and may determine the corresponding cell as a candidate cell for cell selection / reselection. When the value of the intraFreqReselection field included in the MIB is set to "notAllowed", the UE may not select / reselect (multiple) cells using the same frequency as the cell within 300 seconds. When the value of the intraFreqReselection field included in the MIB is set to "allowed", when the (multiple) cells meet the cell reselection criteria, the UE may select the (multiple) cells, and the (multiple) cells use the same frequency as the cell.

[0584] When the selected candidate target cell broadcasts SIB1 in 3g-35, the UE may attempt to receive SIB1 in 3g-65.

[0585] When the UE cannot obtain SIB1, the UE may perform the seventh operation described in 3g-55 in 3g-70.

[0586] When the UE receives SIB1 (upon receiving SIB1), the UE may determine whether the corresponding cell meets the third condition or the fourth condition (3g-75) based on the information included in the MIB and SIB1. The third condition and the fourth condition are as follows.

[0587] Third condition: When the UE identifies the SCS value configured in subCarrierSpacingCommon of the received MIB and does not support the bandwidth of the initial DL BWP and the bandwidth of the initial UL BWP using the SCS value in the configured locationAndBandwidth in the received SIB1

[0588] Fourth condition: When the UE recognizes the SCS value configured in subCarrierSpacingCommon of the received MIB and supports the bandwidths of the initial DL BWP and the initial UL BWP that use the SCS value in the configured locationAndBandwidth in the received SIB1 (if the UE supports the bandwidths of the initial DL / UL BWP in locationAndBandwidth in SIB1)

[0589] Ninth operation: When the third condition is satisfied, in 3g-80, the UE can determine that the corresponding cell is not accessible or can consider the corresponding cell as a prohibited cell, and can exclude the corresponding cell from the candidate cell list for cell selection / reselection within 300 seconds. The UE can refrain from selecting / reselecting (multiple) cells that use the same frequency as the prohibited cell within 300 seconds.

[0590] Tenth operation: When the fourth condition is satisfied, in 3g-85, the UE can determine that the corresponding cell is accessible. Then, the UE can derive the received quality Squal and / or the received level Srxlev of the corresponding cell by using Equation 1 based on the information included in SIB1, and when the received quality Squal and / or the received level Srxlev satisfy the S-criterion (Srxlev > 0 and / or Squal > 0), the UE can finally reselect the corresponding cell; otherwise, the UE can finally refrain from reselecting the corresponding cell.

[0591] Figure 3H A block diagram of a UE according to an embodiment of the present disclosure is shown.

[0592] Reference Figure 3H , the UE may include a radio frequency (RF) processor 3h-10, a baseband processor 3h-20, a storage device 3h-30, and a controller 3h-40. The UE according to an embodiment of the present disclosure may perform operations to implement the embodiments of the present disclosure described above with reference to Figures 1A to 3G the present disclosure described above.

[0593] The RF processor 3h-10 may perform functions for transmitting and receiving signals through a wireless channel, such as frequency band conversion and amplification of signals. That is, the RF processor 3h-10 may up-convert the baseband signal provided from the baseband processor 3h-20 to an RF band signal, then may transmit the RF band signal through an antenna, and may down-convert the RF band signal received through the antenna to a baseband signal. For example, the RF processor 3h-10 may 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), etc.

[0594] Although in Figure 3HOnly one antenna is shown, but the UE may include multiple antennas. The RF processor 3h-10 may include multiple RF chains. The RF processor 3h-10 may perform beamforming. For beamforming, the RF processor 3h-10 may adjust the phase and intensity of signals to be transmitted or received through multiple antennas or antenna elements. The RF processor 3h-10 may perform multiple-input multiple-output (MIMO) operations and may receive data of multiple layers in MIMO operations.

[0595] The baseband processor 3h-20 may convert between baseband signals and bitstreams based on the physical layer specifications of the system. For example, for data transmission, the baseband processor 3h-20 generates complex symbols by encoding and modulating the transmitted bitstream. For data reception, the baseband processor 3h-20 may reconstruct the received bitstream by demodulating and decoding the baseband signal provided by the RF processor 3h-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 3h-20 generates complex symbols by encoding and modulating the transmitted bitstream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing inverse fast Fourier transform (IFFT) and cyclic prefix (CP) insertion. For data reception, the baseband processor 3h-20 may segment the baseband signal provided by the RF processor 3h-10 into OFDM symbol units, reconstruct the signal mapped to subcarriers by performing fast Fourier transform (FFT), and then reconstruct the received bitstream by demodulating and decoding the signal.

[0596] The baseband processor 3h-20 and the RF processor 3h-10 transmit and receive signals as described above. The baseband processor 3h-20 and the RF processor 3h-10 may also be referred to as a transmitter, a receiver, a transceiver, or a communicator. At least one of the baseband processor 3h-20 or the RF processor 3h-10 may include multiple communication modules to support a variety of different radio access technologies. At least one of the baseband processor 3h-20 or the RF processor 3h-10 may include different communication modules to process signals of different frequency bands. For example, different radio access technologies may include wireless local area network (WLAN) (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. Different frequency bands may include super high frequency (SHF) (e.g., 2NRHz or 1NRHz) bands and millimeter wave (mmWave) (e.g., 60GHz) bands.

[0597] The storage device 3h-30 stores basic programs, application programs, and data (e.g., configuration information) for the operation of the UE. Specifically, the storage device 3h-30 may store information about a second access node configured to perform wireless communication by using a second radio access technology. The storage device 3h-30 may provide the stored data according to a request from the controller 3h-40.

[0598] The controller 3h-40 can control the overall operation of the UE. For example, the controller 3h-40 can transmit and receive signals through the baseband processor 3h-20 and the RF processor 3h-10. The controller 3h-40 can record data on the storage device 3h-30 and read data from the storage device 3h-30. In this regard, the controller 3h-40 can include at least one processor. For example, the controller 3h-40 can include a communication processor for controlling communication and an application processor (AP) for controlling the upper layer such as an application program.

[0599] The controller 3h-40 can include a multi-connection processor 3h-42 for performing processing to operate in a multi-connection mode.

[0600] Figure 3I is a block diagram of a BS according to an embodiment of the present disclosure.

[0601] Reference Figure 3I , the BS can include an RF processor 3i-10, a baseband processor 3i-20, a backhaul communicator 3i-30, a storage device 3i-40, and a controller 3i-50.

[0602] The BS according to an embodiment of the present disclosure can perform operations to implement the embodiments of the present disclosure described above with reference to Figures 1A to 3G the embodiments of the present disclosure described.

[0603] The RF processor 3i-10 can perform functions for transmitting and receiving signals through a wireless channel, such as frequency band conversion and amplification of signals. The RF processor 3i-10 can up-convert the baseband signal provided from the baseband processor 3i-20 to an RF band signal, and then can transmit the RF band signal through an antenna, and can down-convert the RF band signal received through the antenna to a baseband signal. For example, the RF processor 3i-10 can include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although only one antenna is shown in Figure 3I , the BS 3i can include multiple antennas. The RF processor 3i-10 can include multiple RF chains. In addition, the RF processor 3i-10 can perform beamforming. For beamforming, the RF processor 3i-10 can adjust the phase and intensity of signals to be transmitted or received through multiple antennas or antenna elements. The RF processor 3i-10 can perform DL MIMO operations by transmitting data of one or more layers.

[0604] The baseband processor 3i-20 can convert between baseband signals and bitstreams based on the physical layer specifications of the first radio access technology. For example, for data transmission, the baseband processor 3i-20 can generate complex symbols by encoding and modulating the transmitted bitstream. For data reception, the baseband processor 3i-20 can reconstruct the received bitstream by demodulating and decoding the baseband signal provided by the RF processor 3i-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 3i-20 can generate complex symbols by encoding and modulating the transmitted bitstream, map the complex symbols to subcarriers, and then configure OFDM symbols by performing IFFT and CP insertion. For data reception, the baseband processor 3i-20 can segment the baseband signal provided by the RF processor 3i-10 into OFDM symbol units, reconstruct the signal mapped to subcarriers by performing FFT, and then reconstruct the received bitstream by demodulating and decoding the signal. The baseband processor 3i-20 and the RF processor 3i-10 can transmit and receive signals as described above. Thus, the baseband processor 3i-20 and the RF processor 3i-10 can also be referred to as transmitters, receivers, transceivers, communicators, or wireless communicators.

[0605] The backhaul communicator 3i-30 can provide an interface for communicating with other nodes in the network. That is, the backhaul communicator 3i-30 can convert the bitstream to be sent from the BS to another node (e.g., a secondary BS or the core network) into a physical signal, and convert the physical signal received from another node into a bitstream.

[0606] The storage device 3i-40 can store basic programs, application programs, and data, such as configuration information, for the operation of the BS. Specifically, the storage device 3i-40 can store, for example, information about the bearers allocated to connected UEs and the measurement results reported from the connected UEs. The storage device 3i-40 can store the standard information for determining whether to provide dual connectivity to the UE or release dual connectivity from the UE. The storage device 3i-40 can provide the stored data according to the request of the controller 3i-50.

[0607] The controller 31-50 can control the overall operation of the BS. For example, the controller 3i-50 can transmit and receive signals through the baseband processor 3i-20 and the RF processor 3i-10 or the backhaul communicator 3i-30. The controller 3i-50 can record data on the storage device 3i-40 and read data from the storage device 3i-40. To this end, the controller 3i-50 can include at least one processor.

[0608] The method according to an embodiment of the present disclosure as described herein or in the appended claims can be implemented as hardware, software, or a combination of hardware and software.

[0609] When implemented as software, a computer-readable storage medium storing one or more programs (e.g., software modules) can be provided. The one or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors in an electronic device. The one or more programs include instructions, where the instructions direct the electronic device to execute a method according to an embodiment of the present disclosure as described herein or in the appended claims.

[0610] The program (e.g., software module or software) can be stored in non-volatile memory, including random access memory (RAM) or flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disc (CD)-ROM, digital versatile disc (DVD), another optical storage device, or magnetic tape cartridges. Alternatively, the program can be stored in a memory including a combination of some or all of the above storage media. Multiple such memories can be included.

[0611] In addition, the program can be stored in an attachable storage device, where the storage device can be accessed through any one or combination of communication networks such as the Internet, intranet, local area network (LAN), wide area LAN (WLAN), and storage area network (SAN). Such a storage device can access the electronic device via an external port. In addition, additional storage devices on the communication network can access the electronic device.

[0612] According to an embodiment of the present disclosure, information about the capabilities of a UE can be easily provided in a mobile communication system. According to an embodiment of the present disclosure, the UE can perform a resource request by using multiple scheduling requests according to the characteristics of the service and the reason for sending the resource request, and thus can be timely allocated UL resources and then send data. According to an embodiment of the present disclosure, in a mobile communication system, in response to channel bandwidth signaling, the UE can effectively perform cell reselection.

[0613] In the above embodiments of the present disclosure, according to the embodiments of the present disclosure, one or more elements included in the present disclosure are expressed in singular or plural forms. However, the singular or plural form is appropriately selected for the case assumed for convenience of description, and the present disclosure is not limited to the singular or plural form, and an element expressed in the singular form can include multiple elements, and an element expressed in the plural form can include a single element.

[0614] Although the present disclosure has been described with various embodiments, those skilled in the art can conceive of various changes and modifications. The present disclosure is intended to include such changes and modifications that fall within the scope of the appended claims.

Claims

1. A user equipment (UE), comprising: a transceiver; and a processor configured to: receive, via the transceiver, a first message from a base station requesting UE capability information, in the case of receiving the first message: set a UE capability field of the UE capability information to include values applicable to all duplex modes and frequency ranges supported by the UE, in the case that the UE supports additional functions in frequency range 1 (FR1) compared to the functions indicated by the set UE capability field, include an FR1 additional UE capability field in the UE capability information and set the FR1 additional UE capability field to include fields reflecting the additional functions applicable to FR1, and in the case that the UE supports additional functions in frequency range 2 (FR2) compared to the functions indicated by the set UE capability field, include an FR2 additional UE capability field in the UE capability information and set the FR2 additional UE capability field to include fields reflecting the additional functions applicable to FR2, and send, via the transceiver, a second message including the UE capability information to the base station as a response to the first message.

2. The UE according to claim 1, wherein the processor is further configured to: in the case of receiving the first message: in the case that the UE supports additional functions in frequency division duplex (FDD) compared to the functions indicated by the set UE capability field, include an FDD additional UE capability field in the UE capability information and set the FDD additional UE capability field to include fields reflecting the additional functions applicable to FDD, in the case that the UE supports additional functions in time division duplex (TDD) compared to the functions indicated by the set UE capability field, include a TDD additional UE capability field in the UE capability information and set the TDD additional UE capability field to include fields reflecting the additional functions applicable to TDD.

3. The UE according to claim 1, wherein in the case that the radio access technology (RAT) type for the first message is set to new radio (NR), the second message includes UE-NR-capability.

4. The UE according to claim 1, wherein in the case that the RAT type for the first message is set to eutra-nr, the second message includes UE-MRDC-capability.

5. A base station for performing communication, the base station comprising: a transceiver; and a processor configured to: send, via the transceiver, a first message requesting UE capability information to a user equipment (UE), and receive, via the transceiver, a second message including UE capability information from the UE as a response to the first message, wherein the UE capability information includes a UE capability field that is set to include values applicable to all duplex modes and frequency ranges supported by the UE, Where, in the case of supporting additional functions of frequency range 1 FR1 at the UE compared to the functions indicated by the UE capability field, the UE capability information includes an FR1 additional UE capability field, and the FR1 additional UE capability field is set to include fields reflecting the additional functions of the FR1, and Where, in the case of supporting additional functions of frequency range 2 FR2 at the UE compared to the functions indicated by the UE capability field, the UE capability information includes an FR2 additional UE capability field, and the FR2 additional UE capability field is set to include fields reflecting the additional functions of the FR2.

6. The base station according to claim 5, Wherein, In the case of supporting additional functions of frequency division duplexing FDD at the UE compared to the functions indicated by the UE capability field, the UE capability information includes an FDD additional UE capability field, and the FDD additional UE capability field is set to include fields reflecting the additional functions of the FDD, and Wherein, in the case of the UE supporting additional functions of time division duplexing TDD compared to the functions indicated by the set UE capability field, the UE capability information includes a TDD additional UE capability field, and the TDD additional UE capability field is set to include fields reflecting the additional functions of the TDD.

7. The base station according to claim 5, Wherein, when the radio access technology RAT type for the first message is set to new radio NR, the second message includes UE-NR-capability..

8. The base station according to claim 5, Wherein, when the RAT type for the first message is set to eutra-nr, the second message includes UE-MRDC-capability.

9. A method performed by a user equipment UE, the method comprising: Receiving a first message requesting UE capability information from a base station; In the case of receiving the first message: Setting the UE capability field of the UE capability information to include values applicable to all duplex modes and frequency ranges supported by the UE; In the case of the UE supporting additional functions of frequency range 1 FR1 compared to the functions indicated by the set UE capability field, including the FR1 additional UE capability field in the UE capability information, and setting the FR1 additional UE capability field to include fields reflecting the additional functions applicable to FR1, and In the case of the UE supporting additional functions of frequency range 2 FR2 compared to the functions indicated by the set UE capability field, including the FR2 additional UE capability field in the UE capability information, and setting the FR2 additional UE capability field to include fields reflecting the additional functions applicable to FR2, and Sending a second message including the UE capability information to the base station as a response to the first message.

10. The method according to claim 9, In the case of receiving the first message: In the case where the UE supports additional functions of frequency division duplexing (FDD) compared to the functions indicated by the set UE capability field, an FDD additional UE capability field is included in the UE capability information, and the FDD additional UE capability field is set to include fields reflecting the additional functions applicable to the FDD. In the case where the UE supports additional functions of time division duplexing (TDD) compared to the functions indicated by the set UE capability field, a TDD additional UE capability field is included in the UE capability information, and the TDD additional UE capability field is set to include fields reflecting the additional functions applicable to the TDD.

11. The method according to claim 9, wherein in the case where the radio access technology (RAT) type for the first message is set to new radio (NR), the second message includes UE-NR-capability.

12. The method according to claim 9, wherein in the case where the RAT type for the first message is set to eutra-nr, the second message includes UE-MRDC-capability.

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