Method and apparatus for providing a frequency band list in a wireless communication system

Abstract

A method includes: selecting a PLMN; receiving a PLMN identity list including PLMN identity information via a first type system information block, wherein each of one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information are listed in a first order of the PLMNs; receiving a PLMN information list including PLMN information via a third type system information block, wherein each of the one or more PLMN information includes an NR band list of the corresponding PLMN, and the order of the NR band list is the same as the first order of the PLMNs; and sending an upper layer indication when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN‑DC by using at least one NR frequency of the selected PLMN.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for providing a frequency band list in a wireless communication system. Background Art

[0002] In order to meet the growing demand for wireless data services after the commercialization of the fourth generation (4G) communication system, considerable efforts have been made to develop a quasi-fifth generation (5G) communication system or a 5G communication system. This is one of the reasons why the "5G communication system" or "quasi-5G communication system" is called a "super-4G network communication system" or a "post-Long Term Evolution (LTE) system". The 5G communication system defined in 3GPP is called a new radio (NR) system. In order to achieve high data rates, the 5G communication system is being developed to be implemented in an ultra-high frequency band (millimeter wave (mmWave) (e.g., a frequency band of 60 GHz)). In order to reduce the path loss of radio waves in such an ultra-high frequency band and increase the transmission distance of radio waves in the 5G communication system, various technologies are being studied, such as: beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas, and these technologies have been applied to the NR system. In order to improve the system network of the 5G communication system, various technologies have been developed, such as evolved small cells, advanced small cells, cloud radio access networks (cloud-RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), and interference cancellation. In addition, for the 5G communication system, other technologies have been developed, such as hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM) and sliding window superposition coding (SWSC), which are advanced coding modulation (ACM) schemes, and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA), which are advanced access schemes.

[0003] The Internet has evolved from a human-based connection network where humans create and consume information to the Internet of Things (IoT), in which distributed components (such as objects) exchange information with each other to process information. Internet of Everything (IoE) technology is emerging, in which technologies related to IoT are combined with technologies for processing big data, such as by connecting to cloud servers. In order to realize IoT, various technical components such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, security technology, etc. are required. In recent years, technologies including sensor networks for connecting objects, machine-to-machine (M2M) communication, machine type communication (MTC), etc. have been studied. In the IoT environment, smart Internet technology (IT) services can be provided to collect and analyze data obtained from objects connected to each other, thereby creating new value in human life. With the integration and combination of existing information technology (IT) technologies and various industries, IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart appliances, high-quality medical services, etc.

[0004] Attempts are being made to apply 5G communication systems to IoT networks. For example, technologies related to sensor networks, M2M communications, MTC, etc. are implemented by using 5G communication technologies including beamforming, MIMO, array antennas, etc. The application of the above-mentioned cloud radio access network (RAN) as a big data processing technology can be an example of the integration of 5G communication technology and IoT technology. Summary of the invention

[0005] Technical issues

[0006] A method and apparatus for providing a frequency band list to a user equipment (UE) in a wireless communication system are provided.

[0007] A terminal for cell reselection in a wireless communication system, comprising: a transceiver; and at least one processor, the at least one processor being configured to select a public land mobile network (PLMN) in an idle mode or an inactive mode, receive a PLMN identity list including one or more PLMN identity information from a base station via a first type system information block, wherein each of the one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information is listed in a first order of (multiple) PLMNs, receive a PLMN information list including one or more PLMN information from the base station via a third type system information block, wherein each of the one or more PLMN information includes a new radio (NR) frequency band list of the corresponding PLMN, and the order of the NR frequency band list is the same as ( The first order of multiple) PLMNs is the same, wherein one or more PLMN identity information is listed in a PLMN identity list received via a first type system information block, determining whether at least one NR frequency of the selected PLMN is included in the NR band list, and whether the terminal supports operation in E-UTRA-NR dual connectivity (EN-DC) by using at least one NR frequency of the selected PLMN, when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the selected PLMN, sending an upper layer indication to an upper layer, and when at least one NR frequency of the selected PLMN is not included in the NR band list or the terminal does not support operation in EN-DC by using at least one NR frequency of the selected PLMN, sending information indicating that the upper layer indication does not exist to the upper layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts:

[0009] Figure 1A is a structural diagram of a long term evolution (LTE) system according to an embodiment of the present disclosure;

[0010] Figure 1B is a diagram of a radio protocol architecture in an LTE system according to an embodiment of the present disclosure;

[0011] Figure 1C is a structural diagram of a next generation mobile communication system according to an embodiment of the present disclosure;

[0012] Figure 1D is a diagram of a radio protocol architecture of a next generation mobile communication system according to an embodiment of the present disclosure;

[0013] Figure 1Eis a diagram for describing a process of determining that a user equipment (UE) in a radio resource control (RRC) idle mode or an RRC inactive mode is located in a specific coverage area according to an embodiment of the present disclosure;

[0014] Figure 1F is a diagram for describing a process of determining whether a UE in an RRC idle mode or an RRC inactive mode supports a specific frequency band according to an embodiment of the present disclosure;

[0015] Figure 1G is a diagram for describing a process of determining whether a UE in an RRC idle mode or an RRC inactive mode supports a specific frequency band according to an embodiment of the present disclosure;

[0016] Figure 1H is a diagram for describing a process of determining whether a UE in an RRC idle mode or an RRC inactive mode supports a specific frequency band according to an embodiment of the present disclosure;

[0017] Fig. 1I is a diagram for describing a process of determining whether a UE in an RRC idle mode or an RRC inactive mode supports a specific frequency band according to an embodiment of the present disclosure;

[0018] Figure 1J is a diagram for describing a process of determining whether a specific frequency band is supported according to an embodiment of the present disclosure;

[0019] Figure 1K is a diagram for describing a process of determining whether a specific frequency range is supported according to an embodiment of the present disclosure;

[0020] Figure 1L is a diagram for describing a process of determining whether a specific frequency band is supported according to an embodiment of the present disclosure;

[0021] Figure 1M is a diagram for describing a process of determining whether a specific frequency band or frequency range is supported according to an embodiment of the present disclosure;

[0022] Figure 1N is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure; and

[0023] Fig.1O is a block diagram of a configuration of a base station according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0024] A method and apparatus for providing a frequency band list to a user equipment (UE) in a wireless communication system are provided.

[0025] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0026] According to an embodiment of the present disclosure, a terminal for cell reselection in a wireless communication system includes: a transceiver; and at least one processor, wherein the at least one processor is configured to select a public land mobile network (PLMN) in an idle mode or an inactive mode, receive a PLMN identity list including one or more PLMN identity information from a base station via a first type system information block, wherein each of the one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information is listed in a first order of the PLMN, and receive a PLMN information list including one or more PLMN information from the base station via a third type system information block, wherein each of the one or more PLMN information includes a new radio (NR) frequency band list of the corresponding PLMN, and the order of the NR frequency band list is the same as that of the PLMN. The first order of N is the same, wherein one or more PLMN identity information is listed in a PLMN identity list received via a first type system information block, determining whether at least one NR frequency of the selected PLMN is included in the NR band list, and whether the terminal supports operation in E-UTRA-NR dual connectivity (EN-DC) by using at least one NR frequency of the selected PLMN, when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the selected PLMN, sending an upper layer indication to the upper layer, and when at least one NR frequency of the selected PLMN is not included in the NR band list or the terminal does not support operation in EN-DC by using at least one NR frequency of the selected PLMN, sending information indicating that the upper layer indication does not exist to the upper layer.

[0027] The at least one processor may also be configured to: receive an upper layer indication from the base station via a second type system information block, and when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the selected PLMN, send an upper layer indication independent of the received upper layer indication to the upper layer, wherein the upper layer indication may provide NR capability to the cell of the selected PLMN indicated to the upper layer.

[0028] The at least one processor may also be configured to: receive a radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration from the base station, determine whether the terminal is configured to operate in EN-DC based on the received RRC connection reconfiguration message, send an upper layer indication to the upper layer when the terminal is configured to operate in EN-DC, and send information to the upper layer indicating that an upper layer indicator does not exist when the terminal is not configured to operate in EN-DC.

[0029] When at least one NR band of the selected PLMN is supported, information associated with the NR configuration may be sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

[0030] The at least one processor may also be configured to send capability information to the base station, the capability information including at least one of information indicating whether the terminal supports EN-DC or information including an NR frequency band supported by the terminal in EN-DC.

[0031] According to an embodiment of the present disclosure, a base station for cell reselection in a wireless communication system includes: a transceiver; and at least one processor, wherein the at least one processor is configured to send a PLMN identity list including one or more public land mobile network (PLMN) identity information to a terminal via a first type system information block, wherein each of the one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information is listed in a first order of (multiple) PLMNs, and send a PLMN information list including one or more PLMN information to the terminal via a third type system information block, wherein each of the one or more PLMN information includes a new radio (NR) frequency band list of the corresponding PLMN, and the NR frequency band list includes a corresponding PLMN. The order of the band list is the same as the first order of (multiple) PLMNs, wherein one or more PLMN identity information is listed in the PLMN identity list received via the first type system information block, wherein, when at least one NR frequency of the PLMN selected by the terminal is included in the NR band list and the terminal supports operation in E-UTRA-NR dual connectivity (EN-DC) by using at least one NR frequency of the PLMN selected by the terminal, an upper layer indication is sent to the upper layer of the terminal, and wherein, when at least one NR frequency of the PLMN selected by the terminal is not included in the NR band list or the terminal does not support operation in EN-DC by using at least one NR frequency of the PLMN selected by the terminal, information indicating that the upper layer indication does not exist is sent to the upper layer of the terminal.

[0032] The at least one processor may also be configured to send an upper layer indication to the terminal via a second type system information block, and wherein, when at least one NR frequency of the PLMN selected by the terminal is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the PLMN selected by the terminal, an upper layer indication independent of the received upper layer indication is sent to the upper layer, and wherein the upper layer indication may indicate to the upper layer that the cell of the PLMN selected by the terminal provides NR capability.

[0033] The at least one processor may also be configured to send a radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration to the terminal, wherein, when the terminal is configured to operate in EN-DC based on the information associated with the NR configuration, an upper layer indication may be sent to an upper layer of the terminal, and wherein, when the terminal is not configured to operate in EN-DC based on the information associated with the NR configuration, information indicating that the upper layer indicator does not exist may be sent to the upper layer of the terminal.

[0034] When at least one NR band of the selected PLMN is supported, information associated with the NR configuration may be sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

[0035] The at least one processor may also be configured to receive capability information from the terminal, the capability information including at least one of information indicating whether the terminal supports EN-DC or information including an NR frequency band supported by the terminal in EN-DC.

[0036] According to an embodiment of the present disclosure, a method for cell reselection in a wireless communication system performed by a terminal includes: selecting a public land mobile network (PLMN) in an idle mode or an inactive mode; receiving a PLMN identity list including one or more PLMN identity information from a base station via a first type system information block, wherein each of the one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information is listed in a first order of (multiple) PLMNs; receiving a PLMN information list including one or more PLMN information from a base station via a third type system information block, wherein each of the one or more PLMN information includes a new radio (NR) frequency band list of the corresponding PLMN, and the order of the NR frequency band list is the same as the first order of (multiple) PLMNs. The sequence is the same, wherein one or more PLMN identity information is listed in a PLMN identity list received via a first type system information block; determining whether at least one NR frequency of the selected PLMN is included in the NR band list, and whether the terminal supports operation in E-UTRA-NR dual connectivity (EN-DC) by using at least one NR frequency of the selected PLMN; when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the selected PLMN, sending an upper layer indication to an upper layer; and when at least one NR frequency of the selected PLMN is not included in the NR band list or the terminal does not support operation in EN-DC by using at least one NR frequency of the selected PLMN, sending information indicating that the upper layer indication does not exist to the upper layer.

[0037] The method may also include receiving an upper layer indication from the base station via a second type system information block, wherein sending the upper layer indication may include, when at least one NR frequency of the selected PLMN is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the selected PLMN, sending an upper layer indication independent of the received upper layer indication to the upper layer, and wherein the upper layer indication may indicate to the upper layer providing NR capability for the cell of the selected PLMN.

[0038] The method may also include: receiving a radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration from the base station; determining whether the terminal is configured to operate in EN-DC based on the received RRC connection reconfiguration message; when the terminal is configured to operate in EN-DC, sending an upper layer indication to the upper layer; and when the terminal is not configured to operate in EN-DC, sending information indicating that the upper layer indicator does not exist to the upper layer.

[0039] When at least one NR band of the selected PLMN is supported, information associated with the NR configuration may be sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

[0040] The method may also include sending capability information to the base station, the capability information including at least one of information indicating whether the terminal supports EN-DC or information including an NR frequency band supported by the terminal in EN-DC.

[0041] According to an embodiment of the present disclosure, a method for cell reselection in a wireless communication system performed by a base station includes: sending a PLMN identity list including one or more public land mobile network (PLMN) identity information to a terminal via a first type system information block, wherein each of the one or more PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more PLMN identity information is listed in a first order of (multiple) PLMNs; and sending a PLMN information list including one or more PLMN information to the terminal via a third type system information block, wherein each of the one or more PLMN information includes a new radio (NR) frequency band list of the corresponding PLMN, and the order of the NR frequency band list is the same as that of (multiple) PLMNs. )PLMNs are the same as the first order of PLMNs, wherein one or more PLMN identity information is listed in a PLMN identity list received via a first type system information block, wherein, when at least one NR frequency of the PLMN selected by the terminal is included in the NR band list and the terminal supports operation in E-UTRA-NR dual connectivity (EN-DC) by using at least one NR frequency of the PLMN selected by the terminal, an upper layer indication is sent to the upper layer of the terminal, and wherein, when at least one NR frequency of the PLMN selected by the terminal is not included in the NR band list or the terminal does not support operation in EN-DC by using at least one NR frequency of the PLMN selected by the terminal, information indicating that the upper layer indication does not exist is sent to the upper layer of the terminal.

[0042] The method may further include sending an upper layer indication to the terminal via a second type system information block, wherein, when at least one NR frequency of the PLMN selected by the terminal is included in the NR band list and the terminal supports operation in EN-DC by using at least one NR frequency of the PLMN selected by the terminal, an upper layer indication independent of the received upper layer indication is sent to the upper layer, and wherein the upper layer indication may indicate to the upper layer that the cell of the PLMN selected by the terminal provides NR capability.

[0043] The method may further include sending a radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration to the terminal, wherein, when the terminal is configured to operate in EN-DC based on the information associated with the NR configuration, an upper layer indication may be sent to the upper layer of the terminal, and wherein, when the terminal is not configured to operate in EN-DC based on the information associated with the NR configuration, information indicating that the upper layer indicator does not exist may be sent to the upper layer of the terminal.

[0044] When at least one NR band of the selected PLMN is supported, information associated with the NR configuration may be sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

[0045] The method may further include receiving capability information from the terminal, the capability information including at least one of information indicating whether the terminal supports EN-DC or information including an NR band supported by the terminal in EN-DC.

[0046] Before entering into the detailed description below, it may be helpful to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprising" and their derivatives mean inclusion rather than limitation; the term "or" is inclusive, meaning and / or; the phrases "associated with" and "associated with" and their derivatives may mean including, included, interconnected, containing, contained within, connected to or connected with, coupled to or coupled with, communicating with, cooperating with, intertwined, juxtaposed, proximate, bound to, having, having the properties of, etc.; and the term "controller" means any device, system, or portion thereof that controls at least one operation, such device may be implemented in hardware, firmware, or software, or some combination of at least two of hardware, firmware, or software. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

[0047] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed by a computer-readable program code and contained in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, instances, related data or parts 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 a read-only memory (ROM), a random access memory (RAM), a hard drive, a compact disk (CD), a digital video disk (DVD) or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical or other communication links that transmit temporary electrical signals 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 subsequently overwritten, such as rewritable optical disks or erasable memory devices.

[0048] Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

[0049] Discussed below FIG. 1A to FIG. 1O The various embodiments used to describe the principles of the present disclosure in this patent document are merely examples and should not be interpreted in any way to limit 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.

[0050] Hereinafter, the operating principle of the present disclosure will be described with reference to the accompanying drawings. While describing the present disclosure, when it is considered that the relevant well-known functions or configurations may unnecessarily obscure the essence of the present disclosure, their detailed description may be omitted. In addition, the terms used below are defined in consideration of the functions in the present disclosure, and may have different meanings according to the intentions, habits, etc. of the user or operator. Therefore, the terms should be defined based on the description in the specification.

[0051] While describing the present disclosure, when it is deemed that related well-known functions or configurations may unnecessarily obscure the essence of the present disclosure, their detailed description may be omitted. Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0052] Throughout the disclosure, the expression "at least one of a, b, or c" means only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

[0053] Examples of the terminal may include a User Equipment (UE), a Mobile Station (MS), a cellular phone, a smart phone, a computer, a multimedia system capable of performing a communication function, and the like.

[0054] In this disclosure, a controller may also be referred to as a processor.

[0055] Throughout the specification, a layer (or a layer arrangement) may also be referred to as an entity.

[0056] In addition, for the convenience of description, terms used to identify access nodes, terms representing network entities, terms representing messages, terms representing interfaces between network entities, terms representing various types of identification information, etc. are used here as examples. Therefore, the terms used in the present disclosure are not limited, and other terms representing objects with the same technical meaning may be used.

[0057] In the following, for the convenience of description, the present disclosure uses the terms and names defined by the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard. However, the present disclosure is not limited to these terms and names and can be equally applied to systems that comply with other standards. In the present disclosure, for the convenience of description, the evolved Node B (eNB) will be used interchangeably with the next generation Node B (gNB). In other words, a base station described as an eNB may also indicate a gNB.

[0058] refer to Figure 1A , the radio access network (RAN) of the LTE system may include evolved Node Bs (eNBs) 1a-05, 1a-10, 1a-15, and 1a-20 (Node Bs (NBs) or base stations), mobility management entities (MMEs) 1a-25, and serving gateways (S-GWs) 1a-30. UEs 1a-35 (or terminals) may access external networks via eNBs 1a-05, 1a-10, 1a-15, or 1a-20 and S-GWs 1a-30.

[0059] exist Figure 1A In the LTE system, eNBs 1a-05 to 1a-20 may correspond to existing NBs of a universal mobile telecommunications system (UMTS). eNBs 1a-05, 1a-10, 1a-15, or 1a-20 may be connected to UE1a-35 via a radio channel, and may perform complex functions compared to existing NBs. In an LTE system, all user services including real-time services such as voice over Internet protocol (VoIP) may be provided via a shared channel. Therefore, an entity of UE 1a-35 needs to be scheduled by collecting status information such as a buffer status, an available transmission power status, and a channel status of UE 1a-35, and eNBs 1a-05, 1a-10, 1a-15, or 1a-20 may operate as the entity.

[0060] A single eNB can generally control multiple cells. For example, an LTE system can use a radio access technology such as orthogonal frequency division multiplexing (OFDM) at a bandwidth of 20 MHz to achieve a data rate of 100 Mbps. In addition, an adaptive modulation and coding (AMC) scheme can be used to determine the modulation scheme and channel coding rate according to the channel state of the UE 1a-35. The S-GW 1a-30 is an entity for providing data bearers, and can configure or release data bearers under the control of the MME 1a-25. The MME1a-25 is an entity for performing mobility management functions and various control functions of the UE 1a-35, and can be connected to the eNB1a-05, eNB a1-10, eNB 1a-15, and eNB 1a-20.

[0061] Figure 1B is a diagram of a radio protocol architecture in an LTE system according to an embodiment of the present disclosure.

[0062] refer to Figure 1B , the radio protocol of the LTE system may include the Packet Data Convergence Protocol (PDCP) layers 1b-05 and 1b-40, the Radio Link Control (RLC) layers 1b-10 and 1b-35, and the Medium Access Control (MAC) layers 1b-15 and 1b-30 for the UE and the eNB, respectively. The PDCP layer 1b-05 or 1b-40 may perform operations such as Internet Protocol (IP) header compression / recovery. The main functions of the PDCP layer 1b-05 or 1b-40 may be summarized as follows.

[0063] -Header compression and decompression: Robust Header Compression Only (ROHC)

[0064] -Transmission of user data

[0065] - In-sequence delivery of upper layer packet data units (PDUs) during PDCP re-establishment in RLC Acknowledged Mode (AM)

[0066] - For split bearers in Dual Connectivity (DC) (supports RLC AM only): PDCP PDU routing for transmission and reordering for reception

[0067] - Duplicate detection of lower layer service data units (SDUs) during PDCP re-establishment under RLC AM

[0068] - Retransmission of PDCP SDUs during handover and retransmission of PDCP PDUs during PDCP data recovery for split bearers in DC

[0069] -Encryption and decryption

[0070] - Timer-based SDU discard in uplink

[0071] The RLC layer 1b-10 or 1b-35 may perform an automatic repeat request (ARQ) operation, for example, by reconfiguring the PDCP PDU to an appropriate size. The main functions of the RLC layer 1b-10 or 1b-35 may be summarized as follows.

[0072] -Transmission of upper layer PDU

[0073] - Error correction through ARQ (for AM data transmission only)

[0074] - Concatenation, segmentation and reassembly of RLC SDUs (only for Unacknowledged Mode (UM) and AM data transmission)

[0075] - Re-segmentation of RLC data PDU (only for AM data transmission)

[0076] - Reordering of RLC data PDUs (only for UM and AM data transmission)

[0077] -Duplicate detection (for UM and AM data transmission only)

[0078] -Protocol error detection (AM data transmission only)

[0079] -RLC SDU discard (only for UM and AM data transmission)

[0080] -RLC reconstruction

[0081] The MAC layer 1b-15 or 1b-30 is connected to a plurality of RLC layers configured for a single UE, and can multiplex RLC PDUs into MAC PDUs and demultiplex RLC PDUs from MAC PDUs. The main functions of the MAC layer 1b-15 or 1b-30 can be summarized as follows.

[0082] - Mapping between logical channels and transport channels

[0083] - Multiplex MAC SDUs belonging to one or different logical channels into a transport block (TB) delivered to the physical layer on a transport channel / demultiplex MAC SDUs belonging to one or different logical channels from a TB delivered by the physical layer on a transport channel

[0084] -Dispatch information report

[0085] - Error correction through HARQ

[0086] - Priority handling between logical channels of a UE

[0087] - Priority handling between UEs through dynamic scheduling

[0088] -Multimedia Broadcast Multicast Service (MBMS) logo

[0089] -Transmission format selection

[0090] -filling

[0091] The physical layer 1b-20 or 1b-25 can encode and modulate the upper layer data channel into OFDM symbols and send the OFDM symbols through the radio channel, or demodulate the OFDM symbols received through the radio channel, channel-decode the OFDM symbols and deliver them to the upper layer.

[0092] Figure 1C is a structural diagram of a next generation mobile communication system according to an embodiment of the present disclosure.

[0093] refer to Figure 1C , the RAN of the next generation mobile communication system (hereinafter, NR or 5G) may include NR gNB 1c-10 (or NR base station) and NR core network (CN) 1c-05. NR UE 1c-15 (or terminal) can access the external network via NR gNB 1c-10 and NRCN 1c-05.

[0094] exist Figure 1CIn the present invention, NR gNB 1c-10 may correspond to the eNB of the existing LTE system. NR gNB1c-10 is connected to NR UE 1c-15 through a radio channel and may provide better services than the existing NB. In the next generation mobile communication system, all user services may be provided via a shared channel. Therefore, it is necessary to schedule an entity of NR UE 1c-15 by collecting status information such as the buffer status, available transmit power status, and channel status of NR UE 1c-15, and NRgNB 1c-10 may operate as the entity. A single NR gNB 1c-10 may control multiple cells. In the next generation mobile communication system, a bandwidth equal to or greater than the current maximum bandwidth may be applied to achieve an ultra-high data rate compared to the current LTE system. In addition, beamforming technology may be grafted by using OFDM as a radio access technology. In addition, the AMC scheme may be used to determine the modulation scheme and channel coding rate according to the channel status of NR UE 1c-15. NR CN 1c-05 may perform functions such as mobility support, bearer establishment, and quality of service (QoS) establishment. NR CN 1c-05 is an entity for performing mobility management functions and various control functions for NR UE1c-15, and can be connected to multiple NR gNB 1c-10. The next-generation mobile communication system can cooperate with the existing LTE system, and NR CN 1c-05 can be connected to MME 1c-25 through a network interface. MME 1c-25 can be connected to eNB 1c-30 which is an existing base station.

[0095] Figure 1D is a diagram of a radio protocol architecture of a next generation mobile communication system according to an embodiment of the present disclosure.

[0096] refer to Figure 1D The radio protocol 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 physical (PHY) layers 1d-20 and 1d-25 for UE and NR gNB, respectively.

[0097] The main functions of NR SDAP layers 1d-01 and 1d-45 may include some of the following functions.

[0098] -Transmission of user plane data

[0099] - Mapping between QoS flows and data radio bearers (DRBs) for both downlink (DL) and uplink (UL)

[0100] - Marking of QoS Flow ID in both DL and UL packets

[0101] - For UL SDAP PDU, reflective QoS flow to DRB mapping

[0102] For NR SDAP layer 1d-01 or 1d-45, the UE may be configured whether to use the header of NR SDAP layer 1d-01 or 1d-45 for each NR PDCP layer 1d-05 or 1d-40, bearer or logical channel, or whether to use the functionality of NR SDAP layer 1d-01 or 1d-45 via an RRC message. When the SDAP header is configured, the 1-bit non-access stratum (NAS) reflective QoS configuration indicator and the 1-bit access stratum (AS) reflective QoS configuration indicator of the SDAP header may indicate that the UE updates or reconfigures the mapping information between QoS flows and data bearers for both UL and DL. The SDAP header may include a QoS flow ID indicating QoS. QoS information may be used as data processing priority information, scheduling information, etc. for supporting smooth services.

[0103] The main functions of NR PDCP layer 1d-05 or 1d-40 may include some of the following functions.

[0104] -Header compression and decompression: ROHC only

[0105] -Transmission of user data

[0106] - In-sequence delivery of upper layer PDUs

[0107] - Out-of-order delivery of upper layer PDUs

[0108] - Reordering of received PDCP PDUs

[0109] - Duplicate detection of lower layer SDU

[0110] -Retransmission of PDCP SDU

[0111] -Encryption and decryption

[0112] - Timer-based SDU discard in uplink

[0113] The reordering function of the NR PDCP layer 1d-05 or 1d-40 may include a function of representing reordering of PDCP PDUs received from a lower layer based on a PDCP sequence number (SN). The reordering function of the NR PDCP layer 1d-05 or 1d-40 may include a function of delivering the reordered data to an upper layer in sequence, or a function of delivering the reordered data immediately regardless of the sequence; may include a function of recording lost PDCP PDUs by reordering the PDCP PDUs; may include a function of reporting status information of lost PDCP PDUs to a transmitter, and may include a function of requesting retransmission of lost PDCP PDUs.

[0114] The main functions of the NR RLC layer 1d-10 or 1d-35 may include at least some of the following functions.

[0115] -Transmission of upper layer PDU

[0116] - In-sequence delivery of upper layer PDUs

[0117] - Out-of-order delivery of upper layer PDUs

[0118] - Error correction via ARQ

[0119] - Concatenation, segmentation and reassembly of RLC SDU

[0120] - Re-segmentation of RLC data PDUs

[0121] - Reordering of RLC data PDUs

[0122] - Duplicate detection

[0123] -Protocol error detection

[0124] -RLC SDU discarded

[0125] -RLC reconstruction

[0126] The in-sequence delivery function of the NR RLC layer 1d-10 or 1d-35 may refer to a function of delivering the RLC SDU received from the lower layer to the higher layer in sequence. When one RLC SDU is segmented into multiple RLC SDUs and received, the in-sequence delivery of the NR RLC layer 1d-10 or 1d-35 may include reassembly and delivery functions.

[0127] The in-sequence delivery of the NR RLC layer 1d-10 or 1d-35 may include a function of reordering received RLC PDUs based on the RLC SN or PDCP SN, a function of recording lost RLC PDUs by reordering the RLC PDUs, a function of reporting status information of lost RLC PDUs to the transmitter, and a function of requesting retransmission of lost RLC PDUs. The in-sequence delivery of the NR RLC layer 1d-10 or 1d-35 may include a function of delivering only the RLC SDUs before the lost RLC SDU when a lost RLC SDU exists. The in-sequence delivery of the NR RLC layer 1d-10 or 1d-35 may include a function of delivering all RLC SDUs received before the start of a specific timer to the upper layer entity in sequence when a specific timer expires despite the presence of lost RLC SDUs. In-sequence delivery of NR RLC layer 1d-10 or 1d-35 may include the function of delivering all currently received RLC SDUs to upper layer entities in sequence when a specific timer expires despite the presence of lost RLC SDUs.

[0128] The NR RLC layer 1d-10 or 1d-35 can process the RLC PDU in the order of receipt, regardless of the order of the sequence number (out-of-order delivery), and deliver it to the NR PDCP layer 1d-05 or 1d-40.

[0129] When the NR RLC layer 1d-10 or 1d-35 receives the segments, the NR RLC layer 1d-10 or 1d-35 can reassemble the segments received later or stored in the buffer into a complete RLC PDU, process the complete RLC PDU, and deliver it to the NR PDCP layer 1d-05 or 1d-40.

[0130] The NR RLC layer 1d-10 or 1d-35 may not have a cascading function, and the cascading function may be performed by the NR MAC layer 1d-15 or 1d-30, or replaced by a multiplexing function of the NR MAC layer 1d-15 or 1d-30.

[0131] In the above description, out-of-order delivery of NR RLC layer 1d-10 or 1d-35 may mean a function of immediately delivering the RLC SDU received from the lower layer to the upper layer out of order. The out-of-order delivery of NR RLC layer 1d-10 or 1d-35 may include a function of reassembling several RLC SDUs when one RLC SDU is initially segmented and received in several RLC SDUs. The out-of-order delivery of NR RLC layer 1d-10 or 1d-35 may include a function of storing the RLC SN or PDCP SN of the received RLC PDU and recording the lost RLC PDU by aligning the received RLC PDUs in sequence.

[0132] The NR MAC layer 1d-15 or 1d-30 can be connected to multiple NR RLC layers 1d-10 or 1d-35 configured for a single UE, and the main functions of the NR MAC layer 1d-15 or 1d-30 may include at least some of the following functions.

[0133] - Mapping between logical channels and transport channels

[0134] -Multiplexing / demultiplexing of MAC SDU

[0135] -Dispatch information report

[0136] - Error correction through HARQ

[0137] - Priority handling between logical channels of a UE

[0138] - Priority handling between UEs through dynamic scheduling

[0139] -MBMS Logo

[0140] -Transmission format selection

[0141] -filling

[0142] The PHY layer 1d-20 or 1d-25 can encode and modulate the upper layer data channel into OFDM symbols and send the OFDM symbols through the radio channel, or demodulate the OFDM symbols received through the radio channel, channel-decode the OFDM symbols and deliver them to the upper layer.

[0143] Figure 1E is a diagram for describing a process of determining that a UE 1e-01 in an RRC idle mode RRC_IDLE or an RRC inactive mode RRC_INACTIVE is located in a specific coverage area according to an embodiment of the present disclosure.

[0144] Hereinafter, for the convenience of description, an example is described in which UE 1e-01 operating in the LTE system is located in the coverage area of ​​the NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1E A diagram for describing a process of determining whether a UE 1e-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) in an LTE system is located in a coverage area where 5G services are provided.

[0145] According to an embodiment of the present disclosure, an LTE base station may signal to UE 1e-01 whether 5G capability is supported as system information. In other words, the LTE base station may signal to UE 1e-01 an indicator of whether NG-RAN E-UTRA-NR dual connectivity ((NG)EN-DC) is supported for each public land mobile network (PLMN) as system information. Based on the indicator included in the system information, UE 1e-01 may determine whether UE 1e-01 is located in a coverage area that supports 5G capability, and accordingly, UE 1e-01 may display a 5G icon by sending an indicator to an upper layer indicating whether 5G is supported.

[0146] refer to Figure 1E In operation 1e-05, UE 1e-01 may establish an RRC connection with an Evolved Universal Telecommunications System (UMTS) Terrestrial Radio Access (EUTRA) cell 1e-02 and is thus in an RRC connected mode (RRC_CONNECTED).

[0147] In operation 1e-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1e-02 may send an RRC connection release message (RRCConnectionRelease) to the UE 1e-01. In operation 1e-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig).

[0148] In operation 1e-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1e-01 may be converted to the RRC inactive mode. When the RRC connection release message does not include the RRC inactive configuration information, the UE 1e-01 may be converted to the RRC idle mode. In other words, the UE 1e-01 that receives the RRC connection release message may be converted to the RRC inactive mode or the RRC idle mode depending on whether the RRC inactive configuration information is included in the RRC connection release message.

[0149] In operation 1e-20, UE 1e-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1e-01 may select a PLMN through the following series of processes.

[0150] -Depending on the capability of UE 1e-01, UE 1e-01 may scan all radio frequency (RF) channels on the E-UTRA frequency band.

[0151] -For each carrier, UE 1e-01 can find the cell with the strongest signal strength and receive system information from that cell.

[0152] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE1e-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured received signal received power (RSRP) value is equal to or greater than -110dBm, UE1e-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE1e-01 can report it to the upper layer together with the RSRP value.

[0153] -When UE 1e-01 supports E-UTRA connected to the 5G Core (5GC) associated with the found PLMN, UE 1e-01 may also report the CN type to the upper layer.

[0154] In operation 1e-25, UE 1e-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may refer to a process in which UE 1e-01 camps on a suitable cell associated with the PLMN selected in operation 1e-20. A suitable cell may refer to a cell that satisfies the following conditions.

[0155] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0156] -When the cell is not barred according to the information provided by the upper layer

[0157] - When the cell is part of at least one Tracking Area (TA) that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list), it belongs to a PLMN that meets the first item above

[0158] In operation 1e-25, UE 1e-01 in RRC idle mode or RRC inactive mode may receive system information to perform a cell selection process. In operation 1e-25, when UE 1e-01 receives SystemInformationBlockType1, UE 1e-01 may use the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN in operation 1e-20. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type (e.g., evolved packet core (EPC) and / or 5GC) supported by the LTE cell. For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For reference, the value of maxPLMN-r11 may be 6. In addition, the PLMN-IdentityInfo of the LTE cell connected to the 5GC can be configured by a plmn-IdentityList of up to maxPLMN-r11. Similarly, the value of maxPLMN-r11 can be 6. An LTE cell can be connected only to the EPC, only to the 5GC, or to both the EPC and the 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0159] - Referring to Table 1, at least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse.

[0160]

Table 1

[0161]

[0162] Hereinafter, PLMN-IdentityInfo will be described with reference to Table 2. At least one PLMN-IdentityInfo may be configured for an LTE cell connected to a 5GC. In addition, when the same PLMN-Identity as that of an LTE cell connected to an EPC is used, each PLMN-IdentityInfo may include a plmn index instead of the PLMN-Identity value itself. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to an EPC. When the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to an EPC. Therefore, because the PLMN-IdentityInfo does not include the same PLMN-Identity value but includes a plmn index, signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to an EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell may determine whether to broadcast the PLMN-Identity or the plmn index via the CHOICE structure, and signal the result of the determination to the UE 1e-01. In addition, for each PLMN, the PLMN-IdentityInfo may include cellReservedForOperatorUse.

[0163]

Table 2

[0164]

[0165] In operation 1e-25, UE 1e-01 may receive SystemInformationBlockType2. In this case, in operation 1e-30, UE 1e-01 may determine whether to send an upperLayerIndication including information that UE 1e-01 is within a coverage area providing 5G services to an upper layer. Specifically, SystemInformationBlockType2 may include upperLayerIndication about providing 5G capabilities for each PLMN in the same order as the PLMN information (PLMN identity / plmn index) included in SystemInformationBlockType1. The corresponding ASN.1 structure is as follows.

[0166] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0167] - Each PLMN-Info may be mapped in the same order of PLMN identities or plmn indices broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0168] - Referring to Table 3, each PLMN-Info may include an upperLayerIndication indicator regarding whether a cell in the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to true (TRUE), the cell in the corresponding PLMN may provide 5G capabilities. Otherwise, the cell in the corresponding PLMN may not provide 5G capabilities.

[0169]

Table 3

[0170]

[0171] When upperLayerIndication is set to TRUE relative to the PLMN (or the selected PLMN identity) selected in operation 1e-25, in operation 1e-30, UE 1e-01 in RRC idle mode or RRC inactive mode may send upperLayerIndication to the upper layer. Otherwise, UE 1e-01 may indicate that the corresponding field does not exist (if the field exists for the selected PLMN, the UE should forward upperLayerIndication to the upper layer, otherwise indicate that the field does not exist). upperLayerIndication may be an indicator notifying the upper layer that UE 1e-01 is in a coverage area providing 5G services (upperLayerIndication is an indication to the upper layer that the UE has entered a coverage area providing 5G capabilities). For reference, when UE 1e-01 sends upperLayerIndication to the upper layer, UE 1e-01 may display a 5G icon on the display of UE 1e-01.

[0172] Figure 1F1 is a diagram for describing a process of determining whether UE 1f-01 supports a specific frequency band according to an embodiment of the present disclosure. In the following, for ease of description, an example is described in which UE 1f-01 operating in an LTE system is located in a coverage area providing NR capabilities, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1F A diagram for describing a process in which an LTE system determines that a UE 1f-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determines whether the UE 1f-01 supports an NR band supporting (NG) EN-DC.

[0173] According to an embodiment of the present disclosure, the EUTRA cell 1f-02 can signal whether 5G capabilities are supported as system information. For example, the EUTRA cell 1f-02 can signal the UE 1f-01 with a list of NR bands supporting (NG) EN-DC for each PLMN as system information. As described in the above-mentioned embodiment of the present disclosure, based on the indicator included in the system information, the UE 1f-01 can determine whether the UE is located in a coverage area that supports 5G capabilities. In addition, based on whether at least one NR band in the list of NR bands supporting (NG) EN-DC included in the system information is supported, the UE 1f-01 can display the 5G icon by sending an indicator indicating 5G capabilities to the upper layer.

[0174] refer to Figure 1F In operation 1f-05, UE 1f-01 can establish an RRC connection with EUTRA cell 1f-02 and is therefore in RRC connected mode (RRC_CONNECTED).

[0175] In operation 1f-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1f-02 may send an RRC connection release message (RRCConnectionRelease) to the UE 1f-01. In operation 1f-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig). In operation 1f-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1f-01 may switch to the RRC inactive mode. In operation 1f-15, when the RRC connection release message does not include the RRC inactive configuration information, the UE 1f-01 may switch to the RRC idle mode. In other words, the UE 1f-01 that receives the RRC connection release message may switch to the RRC inactive mode or the RRC idle mode depending on whether the RRC inactive configuration information is included in the RRC connection release message.

[0176] In operation 1f-20, UE 1f-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1f-01 may select a PLMN through the following series of processes.

[0177] -Depending on the capability of UE 1f-01, UE 1f-01 may scan all RF channels on the E-UTRA band.

[0178] -For each carrier, UE 1f-01 can find the cell with the strongest signal strength and receive system information from that cell.

[0179] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE1f-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, UE 1f-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE 1f-01 can report it to the upper layer together with the RSRP value.

[0180] -When UE 1f-01 supports E-UTRA connected to 5GC for the found PLMN, UE 1f-01 may also report the CN type to the upper layer.

[0181] In operation 1f-25, UE 1f-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may represent a process in which UE 1f-01 resides on a suitable cell associated with the PLMN selected in operation 1f-20. A suitable cell may represent a cell that satisfies the following conditions.

[0182] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0183] - When the cell is not barred according to the most recent information provided by the upper layer

[0184] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the PLMN that satisfies the first item above)

[0185] In operation 1f-25, UE 1f-01 in RRC idle mode or RRC inactive mode can receive system information to perform a cell selection process.

[0186] In operation 1f-25, UE 1f-01 may receive SystemInformationBlockType1. Here, when the PLMN identity or plmn index matching the PLMN selected in operation 1f-20 is included in the cellAccessRelatedInfoList, the plmn-IdentityList, trackingAreaCode, and cellIdentity included in the cellAccessRelatedInfoList may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., evolved packet core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell may be connected only to an EPC, only to a 5GC, or to both an EPC and a 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0187] - Referring to Table 4, at least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse.

[0188]

Table 4

[0189]

[0190] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the 5GC, and when the same PLMN-Identity as that of an LTE cell connected to the EPC is used, each PLMN-IdentityInfo may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to the EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to the EPC. Therefore, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes the plmn index, and thus the signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to the EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell may determine whether to broadcast the PLMN-Identity or the plmn index via the CHOICE structure, and signal the result of the determination to the UE 1f-01. In addition, the PLMN-IdentityInfo may include cellReservedForOperatorUse for each PLMN identity.

[0191]

Table 5

[0192]

[0193] In operation 1f-25, the EUTRA cell 1f-02 may broadcast a list of NR bands supporting (NG) EN-DC for each PLMN as system information. For example, a list of NR bands supporting (NG) EN-DC PLMNs for each PLMN may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). In the present disclosure, a list of NR bands supporting (NG) EN-DC for each PLMN may be broadcast in the same order as the PLMN-Identity / plmn indexes included in the plmn-IdentityList field of SystemInformationBlockType1. In other words, the plmn-IdentityList field does not need to additionally include the PLMN-Identity / plmn index value itself. For example, the ASN.1 structure may have the following structure.

[0194] -Since the NR band list for each PLMN is broadcast via system information in the same order as the plmn-Identity included in the plmn-IdentityList field of SystemInformationBlockType1, a separate plmn-Identity / plmn index may not be included.

[0195] -Some of the plmn-Identities included in the SystemInformationBlockType1 may not support the NR band list supporting (NG) EN-DC. Therefore, the NR band list may be broadcast starting from 0. In other words, when 0 is broadcast for the first band list, the plmn corresponding to the plmn-Identity may indicate that the NR band list supporting (NG) EN-DC is not supported. Obviously, when there is no NR band list supporting (NG) EN-DC in some plmn-Identities, the NR band list may not be broadcast.

[0196] -Some of the plmn-Identities included in the SystemInformationBlockType1 may include multiple NR band lists supporting (NG)EN-DC. In this case, an NR band list including NR bands up to a specific constant value (constant: to be determined (TBD)) may be broadcast.

[0197] - Each NR band supporting (NG) EN-DC can be represented as FreqBandIndicatorNR, absolute RF channel number or carrier frequency. This can be represented as Table 6 below.

[0198]

Table 6

[0199]

[0200]

[0201] According to an embodiment of the present disclosure, the NR band list supporting (NG) EN-DC broadcasted per PLMN via system information may be in the following form.

[0202] -For PLMN-Identity 1, the NR band list supporting (NG)EN-DC may be broadcasted as 10, 20, 30. 10, 20, 30 may represent FreqBandIndicatorNR.

[0203] -For PLMN-Identity 2, the NR band list supporting (NG) EN-DC may be broadcasted as 100, 200, 300. 100, 200, 300 may represent FreqBandIndicatorNR.

[0204] -For PLMN-Identity 3, there may be no NR bands that support (NG) EN-DC. Here, 0 may be broadcast or nothing may be broadcast. This can be represented as shown in Table 7 below.

[0205]

Table 7

[0206]

[0207] In the above table, the three NRFreqBandENCD-List values ​​represent the FreqBandNR-List of each PLMN, and PLMN-Identity 1 corresponds to the first list of NRFreqBandENCD-List values ​​(10, 20, 30), PLMN-Identity 2 corresponds to the second list of NRFreqBandENCD-List values ​​(100, 200, 300), and PLMN-Identity 3 corresponds to the third list of NRFreqBandENCD-List values ​​(0).

[0208] In operation 1f-25, as described above, UE 1f-01 may receive system information including a list of NR bands supporting (NG) EN-DC for each PLMN. Here, UE 1f-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) about the 5G capability of each PLMN provided in the same order as the PLMN information (PLMN identity / plmn index) included in SystemInformationBlockType1. The ASN.1 structure is as follows.

[0209] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0210] - Each PLMN-Info may be mapped in the same order of PLMN Identity / plmn Index broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0211] -Each PLMN-Info may include an upperLayerIndication indicator regarding whether the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to TRUE, the cells in the corresponding PLMN may provide 5G capabilities. Otherwise, the cells in the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication may be set to TRUE only when an NR band supporting (NG) EN-DC exists.

[0212]

Table 8

[0213]

[0214] In operation 1f-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1f-20, and at least one NR band is supported in the NR band list of supporting (NG) EN-DC of the selected PLMN, UE1f-01 may send upperLayerIndication to the upper layer. upperLayerIndication may refer to an indicator used to indicate to the upper layer that UE 1f-01 has entered or is already located in a coverage area providing 5G capabilities and supports at least one NR band in the NR band list supported by the cell of the selected PLMN. Otherwise, UE 1f-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set, and / or at least one NR band is not supported in the NR band list of the selected PLMN, UE 1f-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1f-01 sends upperLayerIndication to the upper layer, UE 1f-01 can display a 5G icon on the display of UE 1f-01.

[0215] In operation 1f-30, UE 1f-01 may send an upperLayerIndication including information to the upper layer, which indicates that the upperLayerIndication of the PLMN registered in operation 1f-20 or the PLMN belonging to the equivalent PLMN list is set to TRUE, and at least one NR band is supported in the NR band list supported by the cell of the corresponding PLMN. Otherwise, UE 1f-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0216] In operation 1f-30, when at least one NR band is supported in the NR band list of supporting (NG) EN-DC of the selected PLMN, UE 1f-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer that at least one NR band is supported in the NR band list of (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, UE 1f-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0217] Figure 1G 1 is a diagram for describing a process of determining whether UE 1g-01 supports a specific frequency band according to an embodiment of the present disclosure. Hereinafter, for the convenience of description, an example is described in which UE 1g-01 operating in an LTE system is located in a coverage area of ​​an NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1G A diagram for describing a process of determining that a UE 1g-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a specific coverage area and determining whether a serving cell supports an NR band supporting (NG) EN-DC.

[0218] According to an embodiment of the present disclosure, an LTE base station may signal whether 5G capability is supported as system information. For example, the LTE base station may signal the UE 1g-01 of the NR band list supporting (NG) EN-DC for each PLMN as system information. Because according to an embodiment of the present disclosure, the NR band list for each PLMN may be the same, when the NR band list is included for the previous PLMN, the previous PLMN index or the previous plmn-Identity may be included for the PLMN supporting the same NR band list. Therefore, the signaling overhead may be reduced because the redundant NR band list is not included in the system information about at least one PLMN. As described in the above-mentioned embodiment of the present disclosure, based on the indicator included in the system information, the UE 1g-01 may determine whether the UE 1g-01 has entered or is located in a coverage area supporting 5G capability. In addition, based on whether at least one NR band in the NR band list supporting (NG) EN-DC included in the system information is supported, the UE 1g-01 may display a 5G icon by sending an indicator indicating 5G capability to an upper layer.

[0219] refer to Figure 1G In operation 1g-05, UE 1g-01 may establish an RRC connection with EUTRA cell 1g-02 and is therefore in RRC connected mode (RRC_CONNECTED).

[0220] In operation 1g-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1g-02 may send an RRC connection release message (RRCConnectionRelease) to the UE 1g-01. In operation 1g-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig).

[0221] In operation 1g-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1g-01 may transition to the RRC inactive mode. When the RRC connection release message does not include the RRC inactive configuration information, the UE 1g-01 may transition to the RRC idle mode. In other words, the UE 1g-01 that receives the RRC connection release message may transition to the RRC inactive mode or the RRC idle mode depending on whether the RRC inactive configuration information is included.

[0222] In operation 1g-20, UE 1g-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1g-01 may select a PLMN through the following series of processes.

[0223] -Depending on the capability of UE 1g-01, UE 1g-01 may scan all RF channels on the E-UTRA band.

[0224] -For each carrier, UE 1g-01 can find the cell with the strongest signal strength and receive system information from that cell.

[0225] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE 1g-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110 dBm, UE 1g-01 can report to the upper layer about the high-quality PLMN, and when it is not equal to or greater than -110 dBm, UE 1g-01 can report it to the upper layer together with the RSRP value.

[0226] -When UE 1g-01 supports E-UTRA connected to 5GC about the found PLMN, UE 1g-01 may also report the CN type to the upper layer.

[0227] In operation 1g-25, UE 1g-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may refer to a process in which UE 1g-01 camps on a suitable cell associated with the PLMN selected in operation 1g-20. The suitable cell may refer to a cell that satisfies the following conditions.

[0228] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0229] -When the cell is not barred according to the information provided by the upper layer

[0230] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to a PLMN that satisfies the first item above)

[0231] In operation 1g-25, UE 1g-01 in RRC idle mode or RRC inactive mode may receive system information to perform a cell selection process. In operation 1g-25, when UE 1g-01 receives SystemInformationBlockType1, the PLMN identity or plmn index corresponding to the PLMN selected in operation 1g-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., Evolved Packet Core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell may be connected only to an EPC, only to a 5GC, or to both an EPC and a 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0232] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse. This may be represented as in Table 9 below.

[0233]

Table 9

[0234]

[0235]

[0236] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to a 5GC, and when the same PLMN-Identity as that of an LTE cell connected to an EPC is used, each PLMN-IdentityInfo may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to an EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to an EPC. In other words, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes a plmn index, and thus signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to an EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell can determine whether to broadcast PLMN-Identity or plmn index via the CHOICE structure, and signal the result of the determination to UE 1g-01. In addition, for each PLMN, PLMN-IdentityInfo can include cellReservedForOperatorUse. This can be represented as Table 10 below.

[0237]

Table 10

[0238]

[0239] In operation 1g-25, the ENTUR cell 1g-02 may broadcast a list of NR bands supporting (NG) EN-DC for each PLMN as system information. For example, a list of NR bands supporting (NG) EN-DC for each PLMN may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). According to an embodiment of the present disclosure, when a specific PLMN includes a NR band list so that the system information does not include a redundant NR band list of at least one PLMN, another PLMN supporting the same NR band list may indicate that the same NR band list is supported by using a specific PLMN identity or a PLMN index indicating a specific PLMN identity. In this case, signaling overhead may be reduced because the redundant band list is not included in the system information of each PLMN.

[0240] -The NR band list for each PLMN may be broadcast in the same order as the PLMN-Identity / plmn index included in the PLMN-IdentityList field of SystemInformationBlockType1.

[0241] -Some plmn-Identities in the plmn-Identity of SystemInformationBlockType1 may not support the NR band list supporting (NG) EN-DC. Therefore, the NR band list may be broadcast starting from 0. In other words, when 0 is broadcast for the NR band list, the plmn corresponding to the plmn-Identity may indicate that the NR band list supporting (NG) EN-DC is not supported. Obviously, when there is no NR band list supporting (NG) EN-DC in some plmn-Identities, the NR band list may not be broadcast.

[0242] -Some of the plmn-Identities included in SystemInformationBlockType1 may include one or more NR band lists supporting (NG) EN-DC. In this case, an NR band list including NR bands up to a maximum specific constant value (Constant TBD) may be broadcast.

[0243] -When the NR band list supporting (NG) EN-DC is included in the previous PLMN, and the same NR band list supporting (NG) EN-DC is supported in the current PLMN, SystemInformationBlockTypex may not include the NR band list, but may include the previous PLMN index or PLMN identity. In other words, the NR band list may be indicated via a selection structure.

[0244] - Each NR frequency band can be indicated by FreqBandIndicatorNR, an absolute RF channel number or a carrier frequency.

[0245] For example, the NR band list supporting (NG) EN-DC broadcasted per PLMN via system information according to an embodiment of the present disclosure may be in the form of the following Table 11.

[0246]

Table 11

[0247]

[0248] In the above table, PLMN-Identity 1 corresponds to the first list of NRFreqBandENCD-List values ​​(10, 20, 30), PLMN-Identity 2 corresponds to the second list of NRFreqBandENCD-List values ​​(1, or PLMN-Identity 1), and PLMN-Identity 3 corresponds to the third list of NRFreqBandENCD-List values ​​(0).

[0249] -For PLMN-Identity 1, the NR band list supporting (NG)EN-DC may be broadcasted as 10, 20, 30. 10, 20, 30 may represent FreqBandIndicatorNR.

[0250] -For PLMN-Identity 2, since the NR band list supporting (NG) EN-DC is the same as the NR band list supported by PLMN-Identity 1, PLMN-Identity 2 may not include the NR band list, but may include PLMN-Identity 1 or the plmn index "1" indicating the PLMN-Identity. Therefore, PLMN-Identity 2 may indicate that the NR band list supporting (NG) EN-DC is 10, 20, 30.

[0251] - For PLMN-Identity 3, there may be no NR bands that support (NG) EN-DC. Here, 0 may be broadcast or nothing may be broadcast.

[0252] In operation 1g-25, as described above, UE 1g-01 may receive system information including a list of NR bands supporting (NG) EN-DC for each PLMN. Here, UE 1g-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) about the 5G capability of each PLMN provided in the same order as the PLMN information (PLMN identity / plmn index) included in SystemInformationBlockType1. The ASN.1 structure is as follows.

[0253] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0254] - Each PLMN-Info may be mapped in the same order of PLMN Identity / plmn Index broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0255] -Each PLMN-Info may include an upperLayerIndication indicator as to whether the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to TRUE, the corresponding PLMN may provide 5G capabilities. Otherwise, the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication may be set to TRUE only when an NR band supporting (NG) EN-DC exists. This can be represented as Table 12 below.

[0256]

Table 12

[0257]

[0258] In operation 1g-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1g-20, and at least one NR band is supported in the NR band list supporting (NG) EN-DC of the selected PLMN, UE1g-01 may send upperLayerIndication to the upper layer. In other words, upperLayerIndication may refer to an indicator for indicating to the upper layer that UE 1g-01 has entered or is located in a coverage area providing 5G capabilities, and the at least one NR band is supported in the NR band list for (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, UE1g-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set, and / or at least one NR band is not supported in the NR band list for (NG) EN-DC of the selected PLMN, UE 1g-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1g-01 sends upperLayerIndication to the upper layer, UE 1g-01 can display a 5G icon on the display of UE 1g-01.

[0259] In operation 1g-30, the UE 1g-01 may send an upperLayerIndication including information to the upper layer, which indicates that the upperLayerIndication of the PLMN registered in operation 1g-20 or the PLMN belonging to the equivalent PLMN list is set to TRUE and supports at least one NR band in the NR band list for (NG) EN-DC with respect to the corresponding PLMN. Otherwise, the UE 1g-01 may indicate to the upper layer that the upperLayerIndication does not exist.

[0260] In operation 1g-30, when at least one NR band is supported in the NR band list supporting (NG) EN-DC of the selected PLMN, the UE 1g-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer that at least one NR band is supported in the NR band list of (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, the UE 1g-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0261] Figure 1H is a diagram for describing a process of determining whether UE 1h-01 supports a specific NR frequency band according to an embodiment of the present disclosure. Hereinafter, for ease of description, an example is described in which UE 1h-01 operating in an LTE system is located in a coverage area of ​​the NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1H A diagram for describing a process of determining that a UE 1h-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determining whether a serving cell supports an NR band supporting (NG) EN-DC.

[0262] According to an embodiment of the present disclosure, an LTE base station may signal whether 5G capability is supported as system information. For example, the LTE base station may signal UE 1h-01 of a list of NR bands supporting (NG) EN-DC for each PLMN list as system information. According to an embodiment of the present disclosure, the NR band list for each PLMN may be the same, and therefore one NR band list may be broadcast for multiple PLMNs via system information. Signaling overhead may be reduced because redundant NR band lists are not included in system information about at least one PLMN. As described in the above-mentioned embodiment of the present disclosure, based on an indicator included in the system information, UE 1h-01 may determine whether UE 1h-01 has entered or is located in a coverage area supporting 5G capability. In addition, based on whether at least one NR band in the list of NR bands supporting (NG) EN-DC included in the system information is supported, UE1h-01 may display a 5G icon by sending an indicator indicating 5G capability to an upper layer.

[0263] refer to Figure 1H In operation 1h-05, UE 1h-01 may establish an RRC connection with EUTRA cell 1h-02 and is therefore in RRC connected mode (RRC_CONNECTED).

[0264] In operation 1h-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1h-02 may send an RRC connection release message (RRCConnectionRelease) to the UE 1h-01. In operation 1h-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig).

[0265] In operation 1h-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1h-01 may be switched to the RRC inactive mode. When the RRC connection release message does not include the RRC inactive configuration information, the UE 1h-01 may be switched to the RRC idle mode. In other words, the UE 1h-01 receiving the RRC connection release message may be switched to the RRC inactive mode or the RRC idle mode depending on whether the RRC inactive configuration information is included.

[0266] In operation 1h-20, UE 1h-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1h-01 may select a PLMN through the following series of processes.

[0267] - Depending on the capability of UE 1h-01, UE 1h-01 may scan all RF channels on the E-UTRA band.

[0268] -For each carrier, UE 1h-01 can find the cell with the strongest signal strength and receive system information from this cell.

[0269] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, the UE1h-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, the UE 1h-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, the UE1h-01 can report it to the upper layer together with the RSRP value.

[0270] -When UE 1h-01 supports E-UTRA connected to 5GC about the found PLMN, UE 1h-01 may also report the CN type to the upper layer.

[0271] In operation 1h-25, the UE 1h-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may refer to a process in which the UE 1h-01 camps on a suitable cell associated with the PLMN selected in operation 1h-20. The suitable cell may refer to a cell that satisfies the following conditions.

[0272] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0273] -When the cell is not barred according to the information provided by the upper layer

[0274] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to a PLMN that satisfies the first item above)

[0275] In operation 1h-25, UE 1h-01 in RRC idle mode or RRC inactive mode may receive system information to perform a cell selection process. In operation 1h-25, when UE 1h-01 receives SystemInformationBlockType1, the PLMN identity / plmn index corresponding to the PLMN selected in operation 1h-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., evolved packet core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell may be connected only to an EPC, only to a 5GC, or to both an EPC and a 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0276] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse. This may be represented as in Table 13 below.

[0277]

Table 13

[0278]

[0279] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to a 5GC, and when the same PLMN-Identity as that of an LTE cell connected to an EPC is used, each PLMN-IdentityInfo may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to an EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to an EPC. In other words, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes a plmn index, and thus signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to an EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell may determine whether to broadcast the PLMN-Identity or the plmn index via the CHOICE structure, and signal the result of the determination to the UE 1h-01. In addition, the PLMN-IdentityInfo may include cellReservedForOperatorUse for each PLMN.

[0280] In operation 1h-25, the ENTUR cell 1h-02 may broadcast a list of NR bands supporting (NG) EN-DC for each PLMN list as system information. For example, a list of NR bands supporting (NG) EN-DC for each PLMN list may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). In an embodiment of the present disclosure, in order to prevent the system information from including a redundant NR band list for at least one PLMN, a plmn-IdentityList or a plmn-IdentityIndexList may be included for at least one PLMN supporting the same NR band, and the NR band mapped thereto may be broadcast via the system information. In this case, signaling overhead may be reduced because the redundant band list is not included in the system information for each PLMN. For example, the ASN.1 structure may have the following structure.

[0281] - When the NR band lists supporting (NG) EN-DC are the same for at least one PLMN, the NR band lists of the same PLMN-IdentityIndexList or PLMN-IdentityList may be broadcasted.

[0282] -Some of the plmn-Identities included in the SystemInformationBlockType1 may not support the NR band list supporting (NG) EN-DC. Therefore, the NR band list may be configured starting from 0. In other words, when 0 is broadcast for the first band list, the plmn corresponding to the plmn-Identity may indicate that the NR band list supporting (NG) EN-DC is not supported. Obviously, when a specific PLMN identity does not include the NR band list, the corresponding PLMN may indicate that the NR band list supporting (NG) EN-DC is not supported.

[0283] - There may be at least one NR band supporting (NG) EN-DC in the PLMN-IdentityIndexList or PLMN-IdentityList. In this case, an NR band list including NR bands up to a maximum specific constant value (Constant TBD) may be broadcast.

[0284] - Each NR frequency band can be indicated by FreqBandIndicatorNR, an absolute RF channel number or a carrier frequency.

[0285] For example, the NR band list supporting (NG) EN-DC broadcasted per PLMN via system information according to an embodiment of the present disclosure may be in the form of Table 14 below.

[0286]

Table 14

[0287]

[0288] In the above table, PLMN-Identity 1, PLMN-Identity 2, and PLMN-Identity 4 correspond to the first list of NRFreqBandENCD-List values ​​(100, 200, 300), respectively, and PLMN-Identity 3 corresponds to the second list of NRFreqBandENCD-List values ​​(0).

[0289] -Since the NR band list supporting (NG) EN-DC is the same as 100, 200, 300 of PLMN-Identity 1, PLMN-Identity 2, and PLMN-Identity 4, SystemInformationBlockTypex may include PLMN-IdentityList, which includes the values ​​of PLMN-Identity 1, PLMN-Identity 2, and PLMN-Identity 4 or PLMN-IdentityIndexList configured as "1", "2", and "4". In addition, the NR band list (100, 200, 300) mapped thereto may be broadcasted by being included in SystemInformationBlockTypex.

[0290] -For PLMN-Identity 3, there may be no NR band that supports (NG) EN-DC. Here, 0 may be broadcast or nothing may be broadcast. Obviously, SystemInformationBlockTypex may include PLMN-Identity 3, or may include a PLMN index "3" indicating PLMN-Identity 3.

[0291] When the list of NR bands supporting (NG) EN-DC is the same for all NRs, a 1-bit indicator may be introduced. In other words, when the 1-bit indicator is set (e.g., TRUE), the 1-bit indicator may indicate that all PLMNs support the same list of NR bands supporting (NG) EN-DC when the NR bands supporting (NG) EN-DC are included.

[0292] In operation 1h-25, as described above, UE 1h-01 may receive system information including a list of NR bands supporting (NG) EN-DC for each PLMN list. Here, UE 1h-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) indicating whether 5G capabilities are provided per PLMN in the same order as SystemInformationBlockType1. The ASN.1 structure is as follows.

[0293] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0294] - Each PLMN-Info may be mapped in the same order of PLMN identities / plmn indices broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn index or plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0295] -Each PLMN-Info may include an upperLayerIndication indicator regarding whether the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to TRUE, the cells in the corresponding PLMN may provide 5G capabilities. Otherwise, the cells of the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication can be set to TRUE only when an NR band supporting (NG) EN-DC exists. This can be represented as Table 15 below.

[0296]

Table 15

[0297]

[0298] In operation 1h-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1h-20, and at least one NR band is supported in the NR band list of the selected PLMN, the UE 1h-01 may send upperLayerIndication to the upper layer. In other words, upperLayerIndication may refer to an indicator for indicating to the upper layer that the UE 1h-01 has entered or is already located in a coverage area providing 5G capabilities and supports at least one NR band in the NR band list supported by the cell of the selected PLMN. Otherwise, the UE 1h-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set, and / or at least one NR band is not supported in the NR band list of the selected PLMN, the UE 1h-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1h-01 sends upperLayerIndication to the upper layer, UE 1h-01 can display a 5G icon on the display of UE 1h-01.

[0299] In operation 1h-30, when upperLayerIndication of the PLMN registered in operation 1h-20 or a PLMN belonging to the equivalent PLMN list is set to TRUE and information that at least one NR band is supported in the NR band list of the corresponding PLMN is included, UE 1h-01 may send upperLayerIndication to the upper layer. Otherwise, UE 1h-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0300] In operation 1h-30, when at least one NR band is supported in the NR band list supporting (NG) EN-DC of the selected PLMN, UE 1h-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer that at least one NR band is supported in the NR band list for (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, UE 1h-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0301] Fig. 1I 1 is a diagram for describing a process of determining whether UE 1i-01 supports a specific NR frequency band according to an embodiment of the present disclosure. In the following, for ease of description, an example is described in which UE 1i-01 operating in an LTE system is located in a coverage area of ​​the NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Fig. 1I A diagram for describing a process in which an LTE system determines that a UE 1i-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determines whether a serving cell supports an NR band supporting (NG) EN-DC.

[0302] According to an embodiment of the present disclosure, an LTE base station may signal whether 5G capability is supported as system information. For example, the LTE base station may signal UE 1i-01 a list of NR bands only for PLMNs supporting (NG) EN-DC as system information. Because a specific PLMN may not support (NG) EN-DC, in an embodiment of the present disclosure, the NR band list is signaled as system information only for PLMNs supporting (NG) EN-DC, so that signaling overhead can be reduced. As described in the above embodiment of the present disclosure, based on the indicator included in the system information, UE 1i-01 can determine whether UE 1i-01 has entered or is located in a coverage area that supports 5G capability. In addition, based on whether at least one NR band in the list of NR bands supporting (NG) EN-DC included in the system information is supported, UE 1i-01 can display a 5G icon by sending an indicator indicating 5G capability to an upper layer.

[0303] refer to Fig. 1I In operation 1i-05, UE 1i-01 may establish an RRC connection with EUTRA cell 1i-02 and is thus in RRC connected mode (RRC_CONNECTED).

[0304] In operation 1i-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1i-02 may send an RRC connection release message (RRCConnectionRelease) to the UE 1i-01. In operation 1i-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig). In operation 1i-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1i-01 may switch to the RRC inactive mode. When the RRC connection release message does not include the RRC inactive configuration information, the UE 1i-01 may switch to the RRC idle mode. In other words, the UE 1i-01 that receives the RRC connection release message may switch to the RRC inactive mode or the RRC idle mode depending on whether the RRC connection release message includes the RRC inactive configuration information.

[0305] In operation 1i-20, UE 1i-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1i-01 may select a PLMN through a series of the following processes.

[0306] -Depending on the capability of UE 1i-01, UE 1i-01 may scan all RF channels on the E-UTRA band.

[0307] -For each carrier, UE 1i-01 can find the cell with the strongest signal strength and receive system information from that cell.

[0308] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE1i-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, UE1i-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE1i-01 can report it to the upper layer together with the RSRP value.

[0309] -When UE 1i-01 supports E-UTRA connected to 5GC relative to the found PLMN, UE 1i-01 may also report the CN type to the upper layer.

[0310] In operation 1i-25, UE 1i-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may refer to a process in which UE 1i-01 camps on a suitable cell associated with the PLMN selected in operation 1i-20. A suitable cell may refer to a cell that satisfies the following conditions.

[0311] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0312] -When the cell is not barred according to the information provided by the upper layer

[0313] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to a PLMN that satisfies the first item above)

[0314] In operation 1i-25, UE 1i-01 in RRC idle mode or RRC inactive mode may receive system information to perform a cell selection process. In operation 1i-25, when UE 1i-01 receives SystemInformationBlockType1, the PLMN identity or plmn index corresponding to the PLMN selected in operation 1i-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., Evolved Packet Core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell may be connected only to an EPC, only to a 5GC, or to both an EPC and a 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0315] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse. This may be represented as in Table 16 below.

[0316]

Table 16

[0317]

[0318]

[0319] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to 5GC, and when the same PLMN-Identity as that of an LTE cell connected to EPC is used, each PLMN-Identity may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-5Identity included in a first PLMN-IdentityInfo of an LTE cell connected to EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to EPC. In other words, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes a plmn index, so that signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the 10LTE cell can determine whether to broadcast PLMN-Identity or plmn index via the CHOICE structure, and signal the result of the determination to UE 1i-01. In addition, PLMN-IdentityInfo can include cellReservedForOperatorUse for each PLMN. This can be represented as Table 17 below.

[0320]

Table 17

[0321]

[0322] In operation 1i-25, the EUTRA cell 1i-02 according to an embodiment of the present disclosure may broadcast the NR band list for (NG) EN-DC as system information only for PLMNs supporting (NG) EN-DC.

[0323] For example, each PLMN list or PLMN's NR band list for (NG) EN-DC PLMN may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). Specifically,

[0324] -The NR band list for (NG)EN-DC may be included in the system information only for PLMNs that support (NG)EN-DC. Here, the system information may include a PLMN identity and an NR band list corresponding to the PLMN identity. In addition, the system information may include a PLMN index for indicating the PLMN identity and an NR band list corresponding to the PLMN index. As described in the above embodiments of the present disclosure, when multiple PLMNs support the same NR band list, a PLMN-IdentityList or a PLMN-IdentityIndexList may be included, and an NR band list corresponding thereto may be included. For example, when the PLMN index is "1", the PLMN index may indicate the plmn-Identity included in the first PLMN-IdentityInfo of the plmn-IdentityList broadcast via SystemInformationBlockType1.

[0325] - Each NR frequency band can be indicated by FreqBandIndicatorNR, an absolute RF channel number or a carrier frequency.

[0326] For example, the broadcast of the NR band list for PLMNs supporting (NG) EN-DC only via system information according to an embodiment of the present disclosure may be in the form of Table 18 below.

[0327]

Table 18

[0328]

[0329] In the above table, PLMN-Identity 4 corresponds to NRFreqBandENCD-List values ​​(10, 20, 30).

[0330] -For PLMN-Identity 4, the NR band list supporting (NG) EN-DC may be broadcasted as 10, 20, 30. 10, 20, 30 may represent FreqBandIndicatoreNR. The NR band list may include the value of PLMN-Identity 4 or the plmn index "4" indicating PLMN-Identity 4.

[0331] - Table 18 may represent a list of NR bands that do not support (NG) EN-DC in PLMN-Identity 1, PLMN-Identity 2, and PLMN-Identity 3.

[0332] When the list of NR bands supporting (NG) EN-DC is the same for all PLMNs, a 1-bit indicator may be introduced. Specifically, when the 1-bit indicator is set (e.g., TRUE), the 1-bit indicator may indicate that when the list of NR bands supporting (NG) EN-DC is included, all PLMNs support the same NR bands for (NG) EN-DC.

[0333] In operation 1i-25, UE 1i-01 may receive system information including the NR band list of the PLMN supporting (NG) EN-DC described above. In operation 1i-25, UE 1i-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) indicating whether 5G capabilities are provided per PLMN in the same order as SystemInformationBlockType1. The ASN.1 structure is as follows.

[0334] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0335] - Each PLMN-Info may be mapped in the same order of PLMN identities or plmn indices broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0336] -Each PLMN-Info may include an upperLayerIndication indicator as to whether the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to TRUE, the corresponding PLMN may provide 5G capabilities. Otherwise, the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication can be set to TRUE only when an NR band supporting (NG) EN-DC exists. This can be represented as Table 19 below.

[0337]

Table 19

[0338]

[0339] In operation 1i-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1i-20, and at least one NR band is supported in the NR band list for (NG) EN-DC of the selected PLMN, UE1i-01 may send upperLayerIndication to the upper layer. In other words, upperLayerIndication may refer to an indicator for indicating to the upper layer that UE 1i-01 has entered or is already located in a coverage area providing 5G capabilities and supports at least one NR band in the NR band list for (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, UE 1i-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set, and / or at least one NR band is not supported in the NR band list of the selected PLMN, UE 1i-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1i-01 sends upperLayerIndication to the upper layer, UE 1i-01 can display a 5G icon on the display of UE 1i-01.

[0340] In operation 1i-30, when upperLayerIndication of the PLMN registered in operation 1i-20 or a PLMN belonging to the equivalent PLMN list is set to TRUE and information that at least one NR band is supported in the NR band list of the corresponding PLMN is included, UE 1i-01 may send upperLayerIndication to the upper layer. Otherwise, UE 1i-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0341] In operation 1i-30, when at least one NR band is supported in the NR band list supporting (NG) EN-DC of the selected PLMN, UE 1i-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer that at least one NR band is supported in the NR band list for (NG) EN-DC supported by the cell of the selected PLMN. Otherwise, UE 1i-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0342] Figure 1J is a diagram for describing a process of determining whether UE 1j-01 supports a specific NR frequency band according to an embodiment of the present disclosure. In the following, for ease of description, an example is described in which UE 1j-01 operating in an LTE system is located in a coverage area of ​​the NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1J It is a diagram for describing a process in which an LTE system determines that a UE 1j-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determines whether a serving cell supports an NR band supporting (NG) EN-DC.

[0343] According to an embodiment of the present disclosure, an LTE base station can signal whether 5G capability is supported as system information. For example, the LTE base station can signal at least one PLMN for each NR band supporting (NG) EN-DC to UE 1j-01 as system information. As described in the above embodiment of the present disclosure, based on the indicator included in the system information, UE1j-01 determines whether UE 1j-01 has entered or is located in a coverage area supporting 5G capability, and determines whether the NR band supporting (NG) EN-DC included in the system information is supported, thereby displaying the 5G icon by sending an indicator indicating 5G capability to the upper layer.

[0344] refer to Figure 1JIn operation 1j-05, UE 1j-01 may establish an RRC connection with EUTRA cell 1j-02 and thus be in RRC connected mode (RRC_CONNECTED). In operation 1j-10, when there is no data transmission / reception due to a specific reason or within a specific time period, EUTRA cell 1j-02 may send an RRC connection release message (RRCconnectionrelease) to UE 1j-01. In operation 1j-10, the RRC connection release message may include RRC inactive configuration information (rrc_InactiveConfig).

[0345] In operation 1j-15, when the RRC inactive message includes RRC inactive configuration information, UE 1j-01 can be converted to RRC inactive mode. When the RRC inactive message does not include RRC inactive configuration information, UE 1j-01 can be converted to RRC idle mode. In other words, UE 1j-01 that receives the RRC connection release message can be converted to RRC inactive mode or RRC idle mode depending on whether the RRC connection release message includes RRC inactive configuration information.

[0346] In operation 1j-20, UE 1j-01 in RRC idle mode or RRC inactive mode can select a PLMN. UE 1j-01 can select a PLMN through a series of the following processes.

[0347] -Depending on the capability of UE 1j-01, UE 1j-01 may scan all RF channels regarding the E-UTRA band.

[0348] -For each carrier, UE 1j-01 can find the cell with the strongest signal strength and receive system information from that cell.

[0349] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE1j-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, UE 1j-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE1j-01 can report it to the upper layer together with the RSRP value.

[0350] -When UE 1j-01 supports E-UTRA connected to 5GC associated with the found PLMN, UE1j-01 may also report the CN type to the upper layer.

[0351] In operation 1j-25, UE 1j-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may represent a process in which UE 1j-01 resides on a suitable cell associated with the PLMN selected in operation 1j-20. A suitable cell may represent a cell that satisfies the following conditions.

[0352] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0353] -When the cell is not barred according to the information provided by the upper layer

[0354] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to a PLMN that satisfies the first item above)

[0355] In operation 1j-25, UE 1j-01 in RRC idle mode or RRC inactive mode may receive system information to perform a cell selection process. In operation 1j-25, when UE 1j-01 receives SystemInformationBlockType1, the PLMN identity or plmn index corresponding to the PLMN selected in operation 1j-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., evolved packet core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value may be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell may be connected only to an EPC, only to a 5GC, or to both an EPC and a 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0356] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse. This may be represented as in Table 20 below.

[0357]

Table 20

[0358]

[0359]

[0360] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to a 5GC, and when the same PLMN-Identity as that of an LTE cell connected to an EPC is used, each PLMN-Identity may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to an EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to an EPC. In other words, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes a plmn index, and thus signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to an EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell can determine whether to broadcast PLMN-Identity or plmn index via the CHOICE structure, and signal the determined result to UE 1j-01. In addition, PLMN-IdentityInfo can include PcellReservedForOperatorUse for each PLMN. This can be represented as Table 21 below.

[0361]

Table 21

[0362]

[0363] In operation 1j-25, the EUTRA cell 1j-02 may broadcast at least one PLMN for each NR band supporting (NG) EN-DC as system information. For example, information about the NR band supporting (NG) EN-DC and at least one PLMN supporting the NR band may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). Specifically,

[0364] -May include information about the NR band supporting (NG) EN-DC and at least one PLMN supporting the NR band. Here, the information about the PLMN may include the value of the PLMN identity itself or a plmn index for indicating the value of the PLMN identity.

[0365] - Each NR frequency band can be indicated by FreqBandIndicatorNR, an absolute RF channel number or a carrier frequency.

[0366] For example, according to an embodiment of the present disclosure, information about at least one PLMN for each NR band supporting (NG) EN-DC broadcast via system information may be in the form of the following Table 22.

[0367]

Table 22

[0368]

[0369] -NR band "10" may be supported in PLMN-Identity 1 and PLMN-Identity 2. The system information may include a PLMN index "1" indicating PLMN-Identity 1 and a PLMN index "2" indicating PLMN-Identity 2, and broadcast NR band "10". The system information may include the value of the PLMN identity itself, instead of the PLMN index.

[0370] - To indicate that NR band "20" is supported in PLMN-Identity 2 and PLMN-Identity 3, the system information may include a PLMN index "2" indicating PLMN-Identity 2 and a PLMN index "3" indicating PLMN-Identity 3, and broadcast NR band "20". In addition, the system information may include the value of the PLMN identity itself instead of the PLMN index.

[0371] - To indicate that NR band '300' is supported in PLMN-Identity 3, the system information may include a PLMN index '3' indicating PLMN-Identity 3, and broadcast NR band '300'. The system information may include the value of the PLMN identity itself, instead of the PLMN index.

[0372] - PLMNs that do not support the NR band may not be signaled.

[0373] In addition, information or an indicator indicating that a specific NR band is supported in all PLMNs may be included. For example, an indicator indicating that a specific NR band is supported in all PLMNs may be set in the system information, and the specific NR band may be included.

[0374] In operation 1j-25, as described above, UE 1j-01 may receive system information including PLMN information for each NR band supporting (NG) EN-DC. In operation 1j-25, UE 1j-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) indicating whether 5G capabilities are provided per PLMN in the same order as SystemInformationBlockType1. The ASN.1 structure is as follows.

[0375] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0376] - Each PLMN-Info may be mapped in the same order of PLMN identities broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0377] -Each PLMN-Info may include an upperLayerIndication indicator as to whether the corresponding PLMN provides 5G capabilities. When upperLayerIndication is set to TRUE, the corresponding PLMN may provide 5G capabilities. Otherwise, the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication may be set to TRUE only when an NR band supporting (NG) EN-DC exists. This may be represented as Table 23 below.

[0378]

Table 23

[0379]

[0380] In operation 1j-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1j-20, and at least one NR band for (NG)EN-DC is supported for the selected PLMN, UE 1j-01 may send upperLayerIndication to the upper layer. In other words, upperLayerIndication may refer to an indicator for indicating to the upper layer that UE 1i-01 has entered or is already located in a coverage area providing 5G capabilities and supports one NR band for (NG)EN-DC supported by at least one cell of the selected PLMN. Otherwise, UE 1j-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set, and / or at least one NR band for (NG)EN-DC is not supported for the selected PLMN, UE 1j-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1j-01 sends upperLayerIndication to the upper layer, UE 1j-01 can display the 5G icon on the display of UE 1j-01.

[0381] In operation 1j-30, when upperLayerIndication of the PLMN registered in operation 1j-20 or a PLMN belonging to the equivalent PLMN list is set to TRUE and information that the corresponding PLMN supports at least one NR band for (NG) EN-DC is included, UE 1j-01 may send upperLayerIndication to the upper layer. Otherwise, UE 1j-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0382] In operation 1j-30, when at least one NR band supporting (NG) EN-DC is supported for the selected PLMN, UE1j-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer at least one NR band for (NG) EN-DC supported by the cell supporting the selected PLMN. Otherwise, UE 1j-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0383] Figure 1K is a diagram for describing a process of determining whether UE 1k-01 supports a specific frequency range according to an embodiment of the present disclosure. Hereinafter, for ease of description, an example is described in which UE 1k-01 operating in an LTE system is located in a coverage area of ​​an NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1K A diagram for describing a process of determining that a UE 1k-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determining whether a serving cell supports an NR frequency range supporting (NG) EN-DC.

[0384] According to an embodiment of the present disclosure, the EUTRA cell 1k-02 can signal whether 5G capability is supported as system information. For example, the EUTRA cell 1k-02 can signal the NR frequency range supporting (NG) EN-DC of each PLMN to the UE 1k-01 as system information. As described in the above embodiment of the present disclosure, the UE 1k-01 can determine whether the UE 1k-01 has entered or is located in a coverage area supporting 5G capability based on an indicator included in the system information, determine whether the broadcast NR frequency range is supported, determine whether the NR frequency range supporting (NG) EN-DC included in the system information is supported, and display the 5G icon by sending an indicator indicating 5G capability to the upper layer.

[0385] refer to Figure 1KIn operation 1k-05, UE 1k-01 can establish an RRC connection with the EUTRA cell 1k-02 and is therefore in RRC connected mode (RRC_CONNECTED).

[0386] In operation 1k-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 1k-02 can send an RRC connection release message (RRCConnectionRelease) to the UE 1k-01. In operation 1k-10, the RRC connection release message can include RRC inactive configuration information (rrc_InactiveConfig).

[0387] In operation 1k-15, when the RRC connection release message includes the RRC inactive configuration information, the UE 1k-01 may be converted to the RRC inactive mode. In operation 1k-15, when the RRC connection release message does not include the RRC inactive configuration information, the UE 1k-01 may be converted to the RRC idle mode. In other words, the UE 1k-01 that receives the RRC connection release message may be converted to the RRC inactive mode or the RRC idle mode depending on whether the RRC connection release message includes the RRC inactive configuration information.

[0388] In operation 1k-20, UE 1k-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 1k-01 may select a PLMN through the following series of processes.

[0389] -Depending on the capability of UE 1k-01, UE 1k-01 may scan all RF channels regarding the E-UTRA band.

[0390] -For each carrier, UE 1k-01 can find the cell with the strongest signal strength and receive system information from the cell.

[0391] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE1k-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, UE1k-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE1k-01 can report it to the upper layer together with the RSRP value.

[0392] -When UE 1k-01 supports E-UTRA connected to 5GC associated with the discovered PLMN, UE 1k-01 may also report the CN type to the upper layer.

[0393] In operation 1k-25, UE 1k-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may refer to a process in which UE 1k-01 resides on a suitable cell associated with the PLMN selected in operation 1k-20. A suitable cell may refer to a cell that satisfies the following conditions.

[0394] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0395] -When the cell is not barred according to the information provided by the upper layer

[0396] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, belonging to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, belonging to a PLMN that satisfies the first item above)

[0397] In operation 1k-25, UE 1k-01 in RRC idle mode or RRC inactive mode can receive system information to perform a cell selection process.

[0398] In operation 1k-25, when UE 1k-01 receives SystemInformationBlockType1, the PLMN identity or plmn index corresponding to the PLMN selected in operation 1k-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., evolved packet core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Optionally, the PLMN-IdentityInfo of an LTE cell connected to an EPC based on a newly defined constant value can be configured by a plmn-IdentityList of up to maxPLMN-r11. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC can be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 can be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC based on a newly defined constant value can be configured by a plmn-IdentityList of up to maxPLMN-r16. An LTE cell can be connected only to the EPC, only to the 5GC, or to both the EPC and the 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0399] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by a plmn-Identity value and cellReservedForOperatorUse. This may be represented as in Table 24 below.

[0400]

Table 24

[0401]

[0402] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the 5GC, and when the same PLMN-Identity as that of an LTE cell connected to the EPC is used, each PLMN-Identity may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in a first PLMN-IdentityInfo of an LTE cell connected to the EPC. In addition, when the plmn index is "2", the plmn index may represent a PLMN-Identity included in a second PLMN-IdentityInfo of an LTE cell connected to the EPC. In other words, the PLMN-IdentityInfo does not include the same PLMN-Identity value, but includes the plmn index, so that signaling overhead may be reduced. When a PLMN-Identity different from that of an LTE cell connected to the EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included. In other words, the LTE cell can determine whether to broadcast PLMN-Identity or plmn index via the CHOICE structure, and signal the determined result to UE 1k-01. In addition, PLMN-IdentityInfo can include cellReservedForOperatorUse for each PLMN. This can be represented as Table 25 below.

[0403]

Table 25

[0404]

[0405] In operation 1k-25, the EUTRA cell 1k-02 may broadcast the NR frequency range supporting (NG) EN-DC for each PLMN as system information. For example, the NR frequency range information supporting (NG) EN-DC for each PLMN may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType (e.g., SystemInformationBlockType27). For example,

[0406] -NR frequency range information supporting (NG) EN-DC for each PLMN may be included. Here, the information about the PLMN may include the value of the PLMN identity itself or a plmn index indicating the value of the PLMN identity. Alternatively, the NR frequency range information may be included in the same order as the PLMNs included in SystemInformationBlockType1. Here, when a specific PLMN does not support the NR frequency range, information indicating that the NR frequency range is not supported may be additionally signaled. For example, the non-support of the NR frequency range may be indicated by broadcasting an indicator indicating that the NR frequency range is not supported or by not broadcasting information about the frequency range (FR).

[0407] - FR1, FR2 or both FR1 and FR2 may be included for NR frequency ranges supporting (NG) EN-DC per PLMN.

[0408] For example, as system information, the NR frequency range information broadcasted for each PLMN supporting (NG) EN-DC may be in the form of the following Table 26.

[0409]

Table 26

[0410]

[0411] In the above table, PLMN-Identity 1 corresponds to the first list of NRFreqBandENCD-List values ​​(FR1, FR2), PLMN-Identity 2 corresponds to the second list of NRFreqBandENCD-List values ​​(FR1), and PLMN-Identity 3 corresponds to the third list of NRFreqBandENCD-List values ​​(not present).

[0412] -PLMN-Identity 1 may indicate that FR1 and FR2 support (NG) EN-DC by including FR1 and FR2.

[0413] -PLMN-Identity 2 may indicate that FR1 supports (NG) EN-DC by including FR1.

[0414] -PLMN-Identity 3 may indicate that EN-DC is not supported (NG) because PLMN-Identity 3 does not include any value.

[0415] Different from Table 26, FR information may be signaled only for PLMNs supporting (NG) EN-DC.

[0416] In operation 1k-25, UE 1k-01 may receive system information including the NR frequency range information of the above-mentioned PLMN supporting (NG) EN-DC.

[0417] In operation 1k-25, UE 1k-01 may receive SystemInformationBlockType2. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) indicating whether 5G capabilities are provided per PLMN in the same order as SystemInformationBlockType1. The ASN.1 structure is as follows.

[0418] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0419] - Each PLMN-Info may be mapped in the same order of PLMN identities broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0420] -Each PLMN-Info may include an upperLayerIndication indicator regarding whether 5G capabilities are provided. When upperLayerIndication is set to TRUE, 5G capabilities may be provided in the corresponding PLMN. Otherwise, the corresponding PLMN may not provide 5G capabilities. For reference, upperLayerIndication may be set to TRUE only when an NR frequency range supporting (NG) EN-DC exists. This may be represented as Table 27 below.

[0421]

Table 27

[0422]

[0423] In operation 1k-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 1k-20, and the NR range is supported for the selected PLMN, the UE 1k-01 may send upperLayerIndication to the upper layer. In other words, upperLayerIndication may refer to an indicator used to indicate to the upper layer that the UE1k-01 has entered or is located in a coverage area providing 5G capabilities and supports at least one NR frequency range in the list of NR frequency ranges supported by the cell of the selected PLMN. Otherwise, the UE 1k-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, FALSE is set to, and / or at least one NR frequency range is not supported in the list of NR frequency ranges of the selected PLMN, the UE1k-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1k-01 sends upperLayerIndication to the upper layer, UE 1k-01 can display a 5G icon on the display of UE 1k-01.

[0424] In operation 1k-30, when the upperLayerIndication of the PLMN registered in operation 1k-20 or the PLMN belonging to the equivalent PLMN list is set to TRUE and at least one NR frequency range is supported in the NR frequency range list of the corresponding PLMN, the UE 1k-01 may send upperLayerIndication to the upper layer. Otherwise, the UE 1k-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0425] In operation 1k-30, when at least one NR frequency range supporting (NG) EN-DC is supported for the selected PLMN, UE 1k-01 may send upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, the upper layer indication may represent an indicator for indicating to the upper layer at least one NR frequency range for (NG) EN-DC supported by the cell supporting the selected PLMN. Otherwise, UE 1k-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, upperLayerIndication may be used differently from the existing upperLayerIndication.

[0426] Figure 1L 1 is a diagram for describing a process of determining whether UE 11-01 supports a specific frequency band according to an embodiment of the present disclosure. In the following, for ease of description, an example is described in which UE 11-01 operating in an LTE system is located in a coverage area of ​​an NR system, but the LTE system and the NR system are only examples, and the embodiments of the present disclosure may be applied to another next generation communication system. Specifically, Figure 1L It is a diagram for describing a process in which an LTE system determines that a UE 11-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determines whether a serving cell supports an NR band supporting (NG) EN-DC.

[0427] According to an embodiment of the present disclosure, an LTE base station may signal whether 5G capabilities are supported as system information. For example, an LTE base station may send a list of NR bands supporting (NG) EN-DC for each PLMN to LTE 11-01 as system information. According to an embodiment of the present disclosure, since all NR bands can be supported for a specific PLMN, 1 bit may be introduced to indicate that all NR bands are supported without including the NR band list, or support for all NR bands may be indicated by not including the NR band list. In addition, 1 bit may be introduced for each NR frequency range to indicate whether all NR band lists are supported for FR1, and whether all NR band lists are supported for FR2. In this case, signaling overhead may be reduced because all NR band lists are not included in the system information of a specific PLMN. As described in the above embodiments of the present disclosure, based on the indicator included in the system information, UE 1l-01 determines whether UE 1l-01 has entered or is located in a coverage area supporting 5G capabilities, and determines whether at least one NR band in the signaling notified NR band list is supported, thereby sending the indicator indicating 5G capabilities to the upper layer and displaying the 5G icon.

[0428] refer to Figure 1L In operation 11-05, UE 11-01 may establish an RRC connection with EUTRA cell 11-02 and is therefore in RRC connected mode (RRC_CONNECTED).

[0429] In operation 11-10, when there is no data transmission / reception due to a specific reason or within a specific time period, the EUTRA cell 11-02 can send an RRC connection release message (RRCConnectionRelease) to the UE 11-01. In operation 11-10, the RRC connection release message can include RRC inactive configuration information (rrc_InactiveConfig).

[0430] In operation 11-15, when the RRC inactive configuration information is included, the UE 11-01 may be converted to the RRC inactive mode. When the RRC inactive configuration information is not included, the UE 11-01 may be converted to the RRC idle mode. In other words, the UE 11-01 that receives the RRC connection release message may be converted to the RRC inactive mode or the RRC idle mode depending on whether the RRC inactive configuration information is included.

[0431] In operation 11-20, UE 11-01 in RRC idle mode or RRC inactive mode may select a PLMN. UE 11-01 may select a PLMN via a series of the following processes.

[0432] -Depending on the capability of UE 11-01, UE 11-01 may scan all RF channels regarding the E-UTRA frequency band.

[0433] -For each carrier, UE 11-01 can find the cell with the strongest signal strength and receive system information from the cell.

[0434] -When at least one PLMN identifier can be received from the cell with the strongest signal strength, UE11-01 can report to the upper layer (e.g., NAS) that the at least one PLMN identifier is a high-quality PLMN. Here, when the measured RSRP value is equal to or greater than -110dBm, UE 11-01 can report the high-quality PLMN to the upper layer, and when it is not equal to or greater than -110dBm, UE11-01 can report it to the upper layer together with the RSRP value.

[0435] -When UE 11-01 supports E-UTRA connected to 5GC associated with the discovered PLMN, UE11-01 may also report the CN type to the upper layer.

[0436] In operation 11-25, UE 11-01 in RRC idle mode or RRC inactive mode may perform a cell selection process. The cell selection process may represent a process in which UE 11-01 camps on a suitable cell associated with the PLMN selected in operation 11-20. A suitable cell may represent a cell that satisfies the following conditions.

[0437] - When the cell is part of a selected PLMN, a registered PLMN or a PLMN in the equivalent PLMN list

[0438] -When the cell is not barred according to the information provided by the upper layer

[0439] - When the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to the above PLMN (the cell is part of at least one TA that is not part of the "Tracking Areas Prohibited from Roaming" list, it belongs to a PLMN that satisfies the first item above)

[0440] In operation 11-25, UE 11-01 in RRC idle mode or RRC inactive mode can receive system information to perform a cell selection process.

[0441] In operation 11-25, when UE 11-01 receives SystemInformationBlockType1, the PLMN identity or plmn index corresponding to the PLMN selected in operation 11-20 may be included in the cellAccessRelatedInfoList. In this case, the plmn-IdentityList, trackingAreaCode, and cellIdentity of the cell received in the corresponding cellAccessRelatedInfoList containing the selected PLMN may be used. Specifically, the plmn-IdentityList may include at least one PLMN-IdentityInfo, and a plmn-IdentityList including at least one PLMN-IdentityInfo may be configured for each core type supported by the LTE cell (e.g., Evolved Packet Core (EPC) and / or 5GC). For example, the PLMN-IdentityInfo of an LTE cell connected to the EPC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to an EPC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. Similarly, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r11. For example, the value of maxPLMN-r11 may be 6. Alternatively, the PLMN-IdentityInfo of an LTE cell connected to a 5GC may be configured by a plmn-IdentityList of up to maxPLMN-r16 by defining a new constant value. An LTE cell may be connected only to the EPC, only to the 5GC, or to both the EPC and the 5GC. The plmn-IdentityList may have the following ASN.1 structure.

[0442] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the EPC, and each PLMN-IdentityInfo may be configured by plmn-Identity and cellReservedForOperatorUse. This may be represented as in Table 28 below.

[0443]

Table 28

[0444]

[0445]

[0446] -At least one PLMN-IdentityInfo may be configured for an LTE cell connected to the 5GC, and when the same PLMN-Identity as the LTE cell connected to the EPC is used, each PLMN-Identity may include a plmn index. For example, when the plmn index is "1", the plmn index may represent a PLMN-Identity included in the first PLMN-IdentityInfo of the LTE cell connected to the EPC, and when the plmn index is "2", the plmn index may represent a PLMN-Identity included in the second PLMN-IdentityInfo of the LTE cell connected to the EPC. By including the plmn index instead of the same PLMN-Identity value, signaling overhead may be reduced. When a PLMN-Identity different from that of the LTE cell connected to the EPC is to be broadcast to each PLMN-IdentityInfo, the PLMN-Identity value itself may be included in the PLMN-IdentityInfo. In other words, the LTE cell may determine whether to broadcast the PLMN-Identity or the plmn index via a CHOICE structure, and signal the determined result to the UE 11-01. Additionally, for each PLMN, cellReservedForOperatorUse may be included.

[0447] In operation 11-25, the EUTRA cell 11-02 according to an embodiment of the present disclosure may broadcast a list of NR bands supporting (NG) EN-DC for each PLMN as system information. For example, a list of NR bands supporting (NG) EN-DC for each PLMN may be broadcast from SystemInformationBlockType1, SystemInformationBlockType2, SystemInformationBlockType5, SystemInformationBlockType24, or a new SystemInformationBlockType1 (e.g., SystemInformationBlockType27). According to an embodiment of the present disclosure, when a list of all NR bands supporting (NG) EN-DC is supported for a specific PLMN, 1 bit may be introduced to indicate that a list of all NR bands supporting (NG) EN-DC is supported for the specific PLMN. Alternatively, for a specific PLMN, 1 bit may be introduced for each FR to indicate whether all NR band lists supporting (NG) EN-DC for each FR are supported. In addition, when all NR band lists supporting (NG) EN-DC are supported for a specific PLMN, it is possible to indicate that all NR band lists are supported by not including the NR band list without introducing 1 bit. Alternatively, when all NR band lists supporting (NG) EN-DC for each FR are supported for a specific PLMN, it is possible to indicate that all NR band lists supporting each FR are supported by not including the NR band list.

[0448] For example,

[0449] - 1 bit may be included to indicate that all NR band lists supporting (NG) EN-DC are supported for a particular PLMN. Alternatively, support for all NR band lists may be indicated by not including the NR band list.

[0450] - 1 bit may be included to indicate that all NR band lists supporting (NG) EN-DC for each FR are supported for a specific PLMN. Alternatively, support for all NR band lists may be indicated by not including the NR band list for each FR.

[0451] - According to the above disclosed embodiment, for a PLMN supporting (NG) EN-DC, an NR band list may be included, or for a PLMN, an NR band list may be included in the same order as the PLMNs included in SystemInformationBlockType1. Alternatively, PLMN information and an NR band supporting (NG) EN-DC for each NR band may be included.

[0452] - Each NR frequency band can be indicated by FreqBandIndicatorNR, an absolute RF channel number or a carrier frequency.

[0453] In operation 11-25, UE 11-01 may receive system information including a list of NR bands supporting (NG) EN-DC for each PLMN described above. In operation 1i-25, SystemInformationBlockType2 may be received. Specifically, SystemInformationBlockType2 may include an indicator (upperLayerIndication) indicating whether each PLMN provides 5G capabilities in the same order as SystemInformationBlockType1. The ASN.1 structure is as follows.

[0454] - A PLMN-InfoList including at least one PLMN-Info may be broadcast in SystemInformationBlockType2.

[0455] - Each PLMN-Info may be mapped in the same order of PLMN identities broadcasted in SystemInformationBlockType1. In other words, the first PLMN-Info may be mapped to the plmn-Identity of the first PLMN-IdentityInfo broadcasted in SystemInformationBlockType1.

[0456] -Each PLMN information may include an upperLayerIndication indicator regarding whether 5G capability is provided. When upperLayerIndication is set to TRUE, the cells in the corresponding PLMN may provide 5G capability. Otherwise, the cells of the corresponding PLMN may not provide 5G capability. For reference, upperLayerIndication can be set to TRUE only when an NR band supporting (NG) EN-DC exists. This can be represented as Table 29 below.

[0457]

Table 29

[0458]

[0459]

[0460] In operation 11-30, when upperLayerIndication is set to TRUE for the PLMN selected in operation 11-20, and at least one NR band is supported in the NR band list for the selected PLMN, UE 11-01 may send upperLayerIndication to the upper layer. upperLayerIndication may refer to indicating to the upper layer that UE 11-01 has entered or is already located in a coverage area providing 5G capabilities, and that for the selected PLMN, at least one NR band is supported in the NR band list supported by the cell. Otherwise, UE 11-01 may indicate to the upper layer that upperLayerIndication does not exist. In other words, when there is no upperLayerIndication for the selected PLMN, upperLayerIndication is set to FALSE, and / or for the selected PLMN, at least one NR band is not supported in the NR band list, UE 11-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, when UE 1l-01 sends upperLayerIndication to the upper layer, UE 1l-01 can display the 5G icon on the display of UE 1l-01.

[0461] Alternatively, in operation 11-30, when the upperLayerIndication of the PLMN registered in operation 11-20 or the PLMN belonging to the equivalent PLMN list is set to TRUE and for the corresponding PLMN, at least one NR band is supported in the NR band list, the UE 11-01 may send upperLayerIndication to the upper layer. Otherwise, the UE 11-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0462] Alternatively, in operation 1l-30, when at least one NR band supporting (NG) EN-DC is supported for the selected PLMN, the UE 1l-01 may send an upperLayerIndication to the upper layer regardless of whether upperLayerIndication is set to TRUE. In other words, upperLayerIndication may represent an indicator for indicating to the upper layer that for the selected PLMN, at least one NR band for (NG) EN-DC supported by the cell is supported. Otherwise, the UE 1l-01 may indicate to the upper layer that upperLayerIndication does not exist. For reference, by introducing a new indicator different from the existing upperLayerIndication, an upperLayerIndication different from the existing upperLayerIndication may be used.

[0463] Figure 1M 1 is a diagram for describing a process of determining whether UE 1m-01 supports a specific frequency band or frequency range according to an embodiment of the present disclosure. Hereinafter, for ease of description, an example is described in which UE 1m-01 operating in an LTE system is located in the coverage area of ​​an NR system, but the LTE system and the NR system are merely examples, and an embodiment of the present disclosure may be applied to another next generation communication system. Figure 1M A diagram for describing a process of determining that a UE 1m-01 in an RRC idle mode (RRC_IDLE) or an RRC inactive mode (RRC_INACTIVE) is located in a coverage area providing 5G capabilities and determining whether an NR band or NR frequency range supporting (NG) EN-DC is supported.

[0464] According to an embodiment of the present disclosure, a base station may add system information including whether 5G capability is supported in dedicated signaling and provide it to UE 1m-01. For example, the dedicated signaling may represent an RRCConnectionReconfiguration message. The system information included in the dedicated signaling may follow the above-mentioned embodiments of the present disclosure. UE 1m-01 in RRC connection mode may determine that UE 1m-01 has entered a coverage area supporting 5G capability based on the system information added to the dedicated signaling, and determine whether the NR band or NR frequency range is supported, thereby sending an indicator indicating 5G capability to the upper layer and displaying the 5G icon.

[0465] refer to Figure 1MIn operation 1m-05, UE 1m-01 may establish an RRC connection with the EUTRA cell 1m-02 and is therefore in an RRC connected mode (RRC_CONNECTED).

[0466] In operation 1m-10, UE 1m-01 in RRC connected mode may send a UE capability information message to EUTRA cell 1m-02. The UE capability information message may include at least one of an indicator of whether EN-DC is supported, an indicator of whether (NG) EN-DC is supported, or a list of NR bands supported in (NG) EN-DC (supportedBandListEN-DC). For reference, supportedBandListEN-DC is a list commonly used for EN-DC and (NG) EN-DC. This is because supportedBandListEN-DC is information about RF and has nothing to do with the core.

[0467] In operation 1m-15, the EUTRA cell 1m-02 may establish (NG) EN-DC by sending an RRC connection reconfiguration message (RRCConnectionReconfiguration) to the UE 1m-01 in RRC connected mode. The RRC connection reconfiguration message may include at least one of nr-SecondaryCellGroupConfig, nr-RadioBearerConfig1, or nr-RadioBearerConfig2.

[0468] In operation 1m-20, the UE 1m-01 in the RRC connected mode may apply the information included in the received RRC connection reconfiguration message and send an RRC connection reconfiguration complete message (RRCConnectionReconfigurationComplete) to the EUTRA cell 1m-02 under test.

[0469] In operation 1m-25, the UE 1m-01 in the RRC connected mode may receive an RRC connection reconfiguration message including a mobilityControlInfo element from the EUTRA cell 1m-02.

[0470] Based on the above-disclosed embodiments, an RRC connection reconfiguration message can be sent to UE 1m-01 via an RRC connection by including system information (e.g., SystemInformationBlockType1, 2, 5, 24, or new) including NR frequency band (list) or NR frequency range information supporting (NG) EN-DC. When UE 1m-01 supports EN-DC and / or EUTRA-5GC, EUTRA cell 1m-02 can send system information to UE 1m-01 by adding the system information to the RRC connection reconfiguration message. Alternatively, EUTRA cell 1m-02 can send an RRC connection reconfiguration message (RRCConnectionReconfiguration) including SystemInformationBlockType24 to UE 1m-01 supporting (NG) EN-DC.

[0471] In operation 1m-30, when upperLayerIndication is set to TRUE for a PLMN registered in SystemInformationBlockType2 broadcasted from a current cell (e.g., a cell performing handover), a selected PLMN, or a PLMN belonging to an equivalent PLMN list, and when, for the corresponding PLMN, the UE 1m-01 supports at least one NR band for (NG) EN-DC, the UE 1m-01 in RRC connected mode may indicate to an upper layer the presence of upperLayerIndication. Information about the NR control band for (NG) EN-DC may be included in the RRC connection reconfiguration message received in operation 1m-25. When upperLayerIndication is not set to TRUE (e.g., set to not exist or FALSE) for a PLMN registered in SystemInformationBlockType2 broadcast from a cell, a selected PLMN, or a PLMN belonging to an equivalent PLMN list, or when upperLayerIndication is set to TRUE but at least one NR band for (NG) EN-DC is not supported, the absence of upperLayerIndication may be indicated to the upper layer.

[0472] In operation 1m-30, when at least one NR band for (NG) EN-DC included in the RRC connection reconfiguration message received in operation 1m-25 is supported, the UE 1m-01 in RRC connection mode may indicate to the upper layer that upperLayerIndication exists. When at least one NR band for (NG) EN-DC is not supported, the UE 1m-01 may indicate to the upper layer that upperLayerIndication does not exist.

[0473] Alternatively, in operation 1m-30, when the RRC connection reconfiguration message received in operation 1m-25 does not include system information (e.g., SystemInformationBlockType 1, 2, 5, 24, or new), the UE 1m-01 in RRC connected mode may indicate to the upper layer that upperLayerIndication does not exist, and the system information includes an NR frequency band (list) or NR frequency range supporting (NG) EN-DC.

[0474] In operation 1m-25, the EUTRA cell 1m-02 may send system information included in an RRC connection reconfiguration message to the UE 1m-01 by configuring the system information in the form of delta signaling. Because the UE 1m-01 receives information about the NR band list for (NG) EN-DC when entering the RRC connected state, the delta signaling may indicate information including only changes in the cell performing the handover. For example, the EUTRA cell 1m-02 may provide only information about PLMNs that are not suitable for the UE1m-01. In other words, by including the system information in the RRC connection reconfiguration message, system information including only information about PLMNs that do not support the NR control band (list) or NR control frequency range for (NG) EN-DC may be sent to the UE1m-01. Alternatively, the EUTRA cell 1m-02 may add information about the PLMN suitable for the UE 1m-01 to the system information, and send the system information by including the system information in the RRC connection reconfiguration message. For example, when only information about the PLMN is included and the NR band (list) or NR frequency range for (NG) EN-DC is not included, the UE 1m-01 can determine that the NR band (list) or NR frequency range for (NG) EN-DC for supporting each PLMN is the same as the information included in the system information received before switching to the RRC connection mode. Obviously, the EUTRA cell 1m-02 can add information about the NR band (list) or NR frequency range for (NG) EN-DC of the PLMN and the new PLMN to the system information, and send the system information to the UE 1m-01 by adding the system information in the RRC connection reconfiguration message.

[0475] In operation 1m-25, the RRC connection reconfiguration message may not include mobilityControlInfo, but may include system information including an NR band (list) or NR frequency range supporting (NG) EN-DC.

[0476] Figure 1N is a block diagram showing an internal structure of a UE according to an embodiment of the present disclosure.

[0477] refer to Figure 1N , the UE includes a radio frequency (RF) processor 1n-10, a baseband processor 1n-20, a storage device 1n-30, and a controller 1n-40. In an embodiment, the controller 1n-40 may include a multi-connection processor 1n-42.

[0478] The RF processor 1n-10 may perform functions such as signal band conversion and amplification for sending and receiving signals through a radio channel. That is, the RF processor 1n-10 up-converts the baseband signal provided by the baseband processor 1n-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1n-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), and an analog-to-digital converter (ADC). Although in Figure 1N Only a single antenna is shown in the figure, but the UE may include multiple antennas. The RF processor 1n-10 may include multiple RF chains. The RF processor 1n-10 may perform beamforming. For beamforming, the RF processor 1n-10 may adjust the phase and amplitude of signals sent or received through multiple antennas or antenna elements. The RF processor 1n-10 may perform MIMO operations and may receive several layers while performing MIMO operations.

[0479] The baseband processor 1n-20 can convert between baseband signals and bit streams based on the physical layer specifications of the system. For example, for data transmission, the baseband processor 1n-20 generates complex symbols by encoding and modulating the transmitted bit stream. For data reception, the baseband processor 1n-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processor 1n-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 1n-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing an inverse fast Fourier transform (IFFT) and a cyclic prefix (CP) insertion. For data reception, the baseband processor 1n-20 can divide the baseband signal provided from the RF processor 1n-10 in units of OFDM symbols, reconstruct the signal mapped to the subcarriers by performing a fast Fourier transform (FFT), and then reconstruct the received bit stream by demodulating and decoding the signal.

[0480] The baseband processor 1n-20 and the RF processor 1n-10 send and receive signals as described above. In this way, each of the baseband processor 1n-20 and the RF processor 1n-10 may also be referred to as a transmitter, a receiver, a transceiver, or a communicator. At least one of the baseband processor 1n-20 or the RF processor 1n-10 may include multiple communication modules to support a variety of different radio access technologies. In addition, at least one of the baseband processor 1n-20 or the RF processor 1n-10 may include multiple communication modules to process signals of different frequency bands. For example, different radio access technologies may include LAN (e.g., IEEE802.11), cellular networks (e.g., LTE), etc. Different frequency bands may include ultra-high frequency (SHF) (e.g., 2.5 GHz and 5 GHz) bands and millimeter wave (e.g., 60 GHz) bands.

[0481] The storage device 1n-30 may store data used for the operation of the UE, such as basic programs, applications, and configuration information. Specifically, the storage device 1n-30 may store information related to a second access node that performs wireless communication by using a second radio access technology. The storage device 1n-30 may provide the stored data according to a request of the controller 1n-40.

[0482] The controller 1n-40 may control the overall operation of the UE. For example, the controller 1n-40 may send and receive signals through the baseband processor 1n-20 and the RF processor 1n-10. The controller 1n-40 may record data on the storage device 1n-30 and read data from the storage device 1n-30. In this regard, the controller 1n-40 may include at least one processor. For example, the controller 1n-40 may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling an upper layer such as an application.

[0483] Fig.1O It is a block diagram of the configuration of an LTE or NR base station according to an embodiment of the present disclosure.

[0484] like Fig.1O As shown, the base station may include an RF processor 1o-10, a baseband processor 1o-20, a backhaul communicator 1o-30, a storage device 1o-40, and a controller 1o-50. In an embodiment, the controller 1o-50 may include a multi-connection processor 1o-52.

[0485] The RF processor 1o-10 can perform functions such as signal band conversion and amplification for sending and receiving signals through a radio channel. That is, the RF processor 1o-10 up-converts the baseband signal provided by the baseband processor 1o-20 into an RF band signal, transmits the RF band signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processor 1o-10 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, and an ADC. Although in Fig.1O Only a single antenna is shown in the figure, but the base station may include multiple antennas. The RF processor 1o-10 may include multiple RF chains. In addition, the RF processor 1o-10 can perform beamforming. For beamforming, the RF processor 1o-10 can adjust the phase and amplitude of the signal sent or received through multiple antennas or antenna elements. The RF processor 1o-10 can perform downlink MIMO operation by sending at least one layer.

[0486] The baseband processor 1o-20 can convert between a baseband signal and a bit stream based on the physical layer specification of the first radio access technology. For example, for data transmission, the baseband processor 1o-20 generates complex symbols by encoding and modulating the transmitted bit stream. For data reception, the baseband processor 1o-20 reconstructs the received bit stream by demodulating and decoding the baseband signal provided from the RF processor 1o-10. For example, according to the OFDM scheme, for data transmission, the baseband processor 1o-20 generates complex symbols by encoding and modulating the transmitted bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing IFFT and CP insertion. For data reception, the baseband processor 1o-20 can divide the baseband signal provided from the RF processor 1o-10 in units of OFDM symbols, reconstruct the signal mapped to the subcarrier by performing FFT, and then reconstruct the received bit stream by demodulating and decoding the signal. The baseband processor 1o-20 and the RF processor 1o-10 send and receive signals as described above. In this way, each of the baseband processor 1o-20 and the RF processor 1o-10 may also be referred to as a transmitter, a receiver, a transceiver, a communicator or a wireless communicator.

[0487] The backhaul communicator 1o-30 can provide an interface for communicating with other nodes in the network. In other words, the backhaul communicator 1o-30 can convert a bit string sent from the main base station to another node (e.g., a secondary base station or a core network) into a physical signal, and convert a physical signal received from another node into a bit string.

[0488] The storage device 1o-40 may store data used for the operation of the main base station, such as basic programs, applications, and configuration information. Specifically, the storage device 1o-40 may store information about bearers allocated to interconnected UEs, measurement reports sent from interconnected UEs, etc. The storage device 1o-40 may store standard information for determining whether to provide or release multiple connections to or from the UE. The storage device 1o-40 may provide the stored data according to the request of the controller 1o-50.

[0489] The controller 1o-50 may control the overall operation of the master base station. For example, the controller 1o-50 may send and receive signals through the baseband processor 1o-20 and the RF processor 1o-10 or through the backhaul communicator 1o-30. The controller 1o-50 may record data on the storage device 1o-40 and read data from the storage device 1o-40. In this regard, the controller 1o-50 may include at least one processor.

[0490] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A terminal for cell reselection in a wireless communication system, the terminal comprising: Transceiver; as well as At least one processor configured to: Select a Public Land Mobile Network (PLMN) in idle mode or inactive mode, receiving a PLMN identity list including one or more pieces of PLMN identity information from a base station via a first type system information block, wherein each of the one or more pieces of PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more pieces of PLMN identity information are listed in a first order of the PLMNs, receiving a PLMN information list including one or more pieces of PLMN information from a base station via a third type system information block, wherein each of the one or more pieces of PLMN information includes a new radio (NR) frequency band list of a corresponding PLMN, and wherein the one or more pieces of PLMN information are listed in the same order as a first order in which the PLMNs in which the one or more pieces of PLMN identity information are listed in the PLMN identity list received via the first type system information block, determining whether a first NR band list of the selected PLMN is included in the PLMN information list, and whether the terminal supports operation in Evolved Universal Terrestrial Radio Access (E-UTRA)-NR Dual Connectivity (EN-DC) by using a serving cell and at least one NR band in the first NR band list, In a case where the first NR band list of the selected PLMN is included in the PLMN information list and the terminal supports operation in EN-DC by using at least one NR band of the serving cell and the selected PLMN, sending an upper layer indication to an upper layer, and In a case where the first NR band list of the selected PLMN is not included in the PLMN information list or the terminal does not support operation in EN-DC by using at least one NR band of the serving cell and the selected PLMN, information indicating that the upper layer indication does not exist is sent to an upper layer.

2. The terminal according to claim 1, wherein: The at least one processor is further configured to: receiving the upper layer indication from a base station via a second type system information block; as well as In a case where the first NR band list of the selected PLMN is included in the PLMN information list and the terminal supports operation in EN-DC by using at least one NR band of the serving cell and the selected PLMN, sending an upper layer indication to the upper layer, The received upper layer indication is an indication to the upper layer that the cell of the selected PLMN provides NR capability.

3. The terminal according to claim 1, wherein: The at least one processor is further configured to: Send capability information to the base station in connected mode, receiving a radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration from the base station, determining, based on the received RRC connection reconfiguration message, whether the terminal is configured to operate in EN-DC, In case the terminal is configured to operate in EN-DC, sending the upper layer indication to the upper layer, and In case the terminal is not configured to operate in EN-DC, information indicating that an upper layer indicator does not exist is transmitted to the upper layer.

4. The terminal according to claim 3, wherein: In case at least one NR frequency band of the selected PLMN is supported, the information associated with the NR configuration is sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

5. The terminal according to claim 3, wherein: The capability information includes at least one of information indicating whether the terminal supports EN-DC or information including an NR frequency band supported by the terminal in EN-DC.

6. A base station for cell reselection in a wireless communication system, comprising: Transceiver; as well as At least one processor configured to: In an idle mode or an inactive mode, sending a public land mobile network (PLMN) identity list including one or more pieces of PLMN identity information to a terminal via a first type system information block, wherein each of the one or more pieces of PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more pieces of PLMN identity information are listed in a first order of the PLMNs, and sending a PLMN information list including one or more pieces of PLMN information to a terminal via a third type system information block, wherein each of the one or more pieces of PLMN information includes a new radio (NR) frequency band list of a corresponding PLMN, and wherein the one or more pieces of PLMN information are listed in the same order as the first order of the PLMNs in which the one or more pieces of PLMN identity information are listed in the PLMN identity list sent via the first type system information block, Wherein, in a case where a first NR band list of a PLMN selected by the terminal is included in the PLMN information list and the terminal supports operation in Evolved Universal Terrestrial Radio Access (E-UTRA)-NR Dual Connectivity (EN-DC) by using a serving cell and at least one NR band in the first NR band list, the upper layer indication is configured to be sent by the terminal to an upper layer of the terminal, and In which, when the first NR band list of the PLMN selected by the terminal is not included in the PLMN information list or the terminal does not support operation in EN-DC by using the serving cell and at least one NR band in the first NR band list, information indicating that the upper layer indication does not exist is configured to be sent by the terminal to the upper layer of the terminal.

7. The base station according to claim 6, wherein: The at least one processor is further configured to send the upper layer indication to the terminal via a second type system information block, and Wherein, in a case where a first NR band list of a PLMN selected by the terminal is included in the PLMN information list and the terminal supports operation in EN-DC by using a serving cell and at least one NR band in the first NR band list, the upper layer indication is configured to be sent by the terminal to an upper layer of the terminal, and The upper layer indication is an indication to the upper layer that the cell of the PLMN selected by the terminal provides NR capability.

8. The base station according to claim 6, wherein: The at least one processor is further configured to: Receive capability information from the terminal in connected mode, sending a radio resource control (RRC) connection reconfiguration message to the terminal, the radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration, Wherein, in a case where the terminal is configured to operate in EN-DC based on the information associated with the NR configuration, the upper layer indication is configured to be sent by the terminal to an upper layer of the terminal, and Wherein, when the terminal is not configured to operate in EN-DC based on the information associated with the NR configuration, information indicating that the upper layer indicator does not exist is configured to be sent by the terminal to the upper layer of the terminal.

9. The base station according to claim 8, wherein: In case at least one NR frequency band of the selected PLMN is supported, the information associated with the NR configuration is sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

10. The base station according to claim 8, wherein: The capability information includes at least one of information indicating whether the terminal supports EN-DC or information including an NR frequency band supported by the terminal in EN-DC.

11. A method for cell reselection performed by a terminal in a wireless communication system, the method comprising: Select a Public Land Mobile Network (PLMN) in idle mode or inactive mode; receiving, from a base station via a first type system information block, a PLMN identity list including one or more pieces of PLMN identity information, wherein each of the one or more pieces of PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more pieces of PLMN identity information are listed in a first order of the PLMNs; receiving a PLMN information list including one or more pieces of PLMN information from a base station via a third type system information block, wherein each of the one or more pieces of PLMN information includes a new radio (NR) frequency band list of a corresponding PLMN, and wherein the one or more pieces of PLMN information are listed in the same order as a first order in which the PLMNs in which the one or more pieces of PLMN identity information are listed in the PLMN identity list received via the first type system information block; determining whether a first NR band list of the selected PLMN is included in the PLMN information list, and whether the terminal supports operation in (E-UTRA)-NR dual connectivity (EN-DC) by using a serving cell and at least one NR band in the first NR band list; In a case where a first NR band list of the selected PLMN is included in the PLMN information list and the terminal supports operation in EN-DC by using a serving cell and at least one NR band in the first NR band list, sending an upper layer indication to an upper layer; and In a case where the first NR band list of the selected PLMN is not included in the PLMN information list or the terminal does not support operation in EN-DC by using at least one NR band of the serving cell and the selected PLMN, information indicating that the upper layer indication does not exist is sent to an upper layer.

12. The method according to claim 11, further comprising receiving the upper layer indication from a base station via a second type system information block, in, The sending of the upper layer indication comprises: sending the upper layer indication to the upper layer if the first NR band list of the selected PLMN is included in the PLMN information list and the terminal supports operation in EN-DC by using at least one NR band of the serving cell and the selected PLMN, and The upper layer indication is an indication to the upper layer that the cell of the selected PLMN provides NR capability.

13. The method according to claim 11, further comprising: Send capability information to the base station in connected mode, receiving a radio resource control (RRC) connection reconfiguration message from a base station, the radio resource control (RRC) connection reconfiguration message including information associated with the NR configuration; determining, based on the received RRC connection reconfiguration message, whether the terminal is configured to operate in EN-DC; In case the terminal is configured to operate in EN-DC, sending the upper layer indication to the upper layer; and In case the terminal is not configured to operate in EN-DC, information indicating that an upper layer indicator does not exist is transmitted to the upper layer.

14. The method according to claim 13, wherein: In case at least one NR frequency band of the selected PLMN is supported, the information associated with the NR configuration is sent to the terminal in connected mode within an RRC Connection Reconfiguration message.

15. A method for cell reselection performed by a base station in a wireless communication system, the method comprising: In an idle mode or an inactive mode, sending a public land mobile network (PLMN) identity list including one or more pieces of PLMN identity information to a terminal via a first type system information block, wherein each of the one or more pieces of PLMN identity information includes a PLMN identity of a corresponding PLMN, and the one or more pieces of PLMN identity information are listed in a first order of the PLMNs; and sending a PLMN information list including one or more pieces of PLMN information to a terminal via a third type system information block, wherein each of the one or more pieces of PLMN information includes a new radio (NR) frequency band list of a corresponding PLMN, and wherein the one or more pieces of PLMN information are listed in the same order as the first order of the PLMNs in which the one or more pieces of PLMN identity information are listed in the PLMN identity list sent via the first type system information block, Wherein, in a case where a first NR band list of a PLMN selected by the terminal is included in the PLMN information list and the terminal supports operation in an evolved universal terrestrial radio access (E-UTRA)-NR dual connectivity (EN-DC) by using a serving cell and at least one NR band in the first NR band list, an upper layer indication is configured to be sent by the terminal to an upper layer of the terminal, and In which, when the first NR band list of the PLMN selected by the terminal is not included in the PLMN information list or the terminal does not support operation in EN-DC through the serving cell and at least one NR band in the first NR band list, information indicating that the upper layer indication does not exist is configured to be sent by the terminal to the upper layer of the terminal.

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