Method and apparatus for performing paging and random access based on low-power wake-up receiver in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. According to various embodiments of the present disclosure, a method performed by a user equipment (UE) in a wireless communication system may comprise the steps of: receiving a system information block (SIB) including information on a frequency of a second band from a base station on a first cell of a first band; receiving a wake-up signal (WUS) from the base station on the first cell of the first band; receiving a paging message from the base station on the first cell of the first band on the basis of the WUS; performing a cell reselection procedure for a second cell of the second band; and performing a random access procedure on the second cell of the second band.

Description

Method and apparatus for performing paging and random access according to a low-power wake-up receiver in a wireless communication system

[0001] The present disclosure relates to the operation of a terminal and a base station in a wireless communication system. More specifically, the present disclosure relates to a method for a terminal having a low-power wake-up receiver to perform procedures related to paging and random access, and an apparatus capable of performing such procedures.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in frequency bands below 6 GHz ('Sub 6 GHz'), such as 3.5 gigahertz (3.5 GHz), but also in ultra-high frequency bands called millimeter waves (mmWave), such as 28 GHz and 39 GHz ('Above 6 GHz'). In addition, for 6G mobile communication technology, which is referred to as a system beyond 5G, implementation in the terahertz (THX) band (e.g., the 3 terahertz band at 95 GHz) is being considered to achieve transmission speeds 50 times faster and ultra-low latency reduced to one-tenth compared to 5G mobile communication technology.

[0003] In the early stages of 5G mobile communication technology, aiming to satisfy service support and performance requirements for enhanced Mobile BroadBand (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), technologies such as beamforming and Massive MIMO to mitigate path loss and increase transmission distance in ultra-high frequency bands, support for various numerologies (such as the operation of multiple subcarrier spacings) and dynamic operation of slot formats for the efficient utilization of ultra-high frequency resources, initial access techniques to support multi-beam transmission and broadband, definition and operation of Band-Width Parts (BWP), Low Density Parity Check (LDPC) codes for high-volume data transmission, new channel coding methods such as Polar Codes for the reliable transmission of control information, and L2 pre-processing (L2 Standardization has been carried out for pre-processing, network slicing which provides a dedicated network specialized for specific services, and other methods.

[0004] Currently, discussions are underway to improve and enhance the performance of the initial 5G mobile communication technology, taking into account the services that the 5G mobile communication technology was intended to support. Additionally, standardization of the physical layer is in progress for technologies such as V2X (Vehicle-to-Everything), which helps autonomous vehicles make driving decisions and enhance user convenience based on their own location and status information transmitted by the vehicle; NR-U (New Radio Unlicensed), which aims for system operation in unlicensed bands to comply with various regulatory requirements; NR terminal low power consumption technology (UE Power Saving); Non-Terrestrial Network (NTN), which is direct terminal-satellite communication for securing coverage in areas where communication with the terrestrial network is impossible; and positioning.

[0005] In addition, standardization is underway in the field of wireless interface architecture / protocols for technologies such as the Industrial Internet of Things (IIoT) for supporting new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) which provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement including Conditional Handover and Dual Active Protocol Stack (DAPS) Handover, and 2-step Random Access (2-step RACH for NR) which simplifies random access procedures. Standardization is also underway in the field of system architecture / services for 5G baseline architectures (e.g., Service based Architecture, Service based Interface) for incorporating Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC), which provides services based on the location of the terminal.

[0006] When such 5G mobile communication systems are commercialized, connected devices, which are increasing explosively, will be connected to communication networks. Accordingly, it is expected that there will be a need to enhance the functionality and performance of 5G mobile communication systems and to integrate the operation of connected devices. To this end, new research is planned to be conducted on 5G performance improvement and complexity reduction, support for AI services, support for metaverse services, and drone communication using eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] Furthermore, the advancement of these 5G mobile communication systems encompasses multi-antenna transmission technologies such as new waveforms to guarantee coverage in the terahertz band of 6G mobile communication technology, Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas; metamaterial-based lenses and antennas to improve terahertz band signal coverage; high-dimensional spatial multiplexing technology using OAM (Orbital Angular Momentum); and Reconfigurable Intelligent Surface (RIS) technology; as well as Full Duplex technology for enhancing frequency efficiency and system networks in 6G mobile communication technology; AI-based communication technologies that realize system optimization by utilizing satellites and AI from the design stage and internalizing end-to-end AI support functions; and the realization of services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources. It could serve as a foundation for the development of next-generation distributed computing technologies.

[0008] Based on the discussion described above, the disclosed embodiment aims to provide an apparatus and method capable of effectively providing services in a mobile communication system.

[0009] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below.

[0010] According to various embodiments of the present disclosure, a method performed by a terminal (user equipment, UE) in a wireless communication system may include: receiving a system information block (SIB) containing information about a frequency of a second band on a first cell of a first band from a base station; receiving a wake-up signal (WUS) from the base station on the first cell of the first band; receiving a paging message based on the WUS from the base station on the first cell of the first band; performing a cell reselection procedure for a second cell of the second band; and performing a random access procedure on the second cell of the second band.

[0011] According to various embodiments of the present disclosure, in a wireless communication system, a terminal (user equipment, UE) comprises: at least one transceiver; and at least one processor communicatively coupled to the at least one transceiver; and may include at least one memory that is communicationally coupled to the at least one processor and stores instructions, and the instructions may be executed by the at least one processor individually or in any combination so that the terminal: receives a system information block (SIB) containing information about a frequency of a second band on a first cell of a first band from a base station, receives a wake-up signal (WUS) from the base station on the first cell of the first band, receives a paging message based on the WUS from the base station on the first cell of the first band, performs a cell reselection procedure for a second cell of the second band, and performs a random access procedure on the second cell of the second band.

[0012] According to an embodiment of the present disclosure, an apparatus and method capable of effectively providing services in a wireless communication system are provided.

[0013] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0014] FIG. 1 illustrates the structure of an LTE system according to one embodiment of the present invention.

[0015] FIG. 2 illustrates a wireless protocol structure in an LTE system according to one embodiment of the present invention.

[0016] FIG. 3 illustrates the structure of a next-generation mobile communication system according to one embodiment of the present invention.

[0017] FIG. 4 illustrates the wireless protocol structure of a next-generation mobile communication system according to one embodiment of the present invention.

[0018] FIG. 5 illustrates a cell reselection evaluation procedure for a terminal in an RRC idle mode (RRC_IDLE) or RRC disabled state (RRC_INACTIVE) in a next-generation mobile communication system according to an embodiment of the present invention.

[0019] FIG. 6 illustrates a procedure in which a terminal performs an RRC connection establishment procedure with a base station according to an embodiment of the present invention to switch from an RRC idle mode (RRC_IDLE) to an RRC connected mode (RRC_CONNECTED).

[0020] FIG. 7 illustrates a procedure in which a terminal performs an RRC connection resume procedure with a base station according to an embodiment of the present invention to switch from an RRC inactive mode (RRC_INACTIVE) to an RRC connected mode (RRC_CONNECTED).

[0021] FIG. 8 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to report a band list supported by the low-power wake-up receiver to a base station.

[0022] FIG. 9 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention, which determines a predetermined frequency as the highest reselection priority to perform a cell reselection procedure and triggers a random access procedure in a reselected cell.

[0023] FIG. 10 illustrates the flow of another signal for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention, which determines a predetermined frequency as the highest reselection priority to perform a cell reselection procedure and triggers a random access procedure in the reselected cell.

[0024] FIGS. 11a and 11b illustrate the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to perform a cell reselection procedure by applying a predetermined frequency-specific reselection priority and to trigger a random access procedure in a reselected cell.

[0025] FIG. 12 illustrates the flow of signals for a terminal to perform a random access procedure when a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention fails to re-select a cell.

[0026] FIG. 13 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to continue performing a cell reselection procedure according to a predetermined condition after initiating a random access procedure.

[0027] FIG. 14 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to monitor a downlink signal transmitted by a cell or base station belonging to a different band than the cell or base station that received the low-power wake-up signal.

[0028] FIG. 15 illustrates the structure of a terminal according to one embodiment of the present invention.

[0029] FIG. 16 illustrates the structure of a base station according to one embodiment of the present invention.

[0030] The operating principle of the present invention will be described in detail below with reference to the attached drawings. In describing the present invention below, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the invention. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0031] In the following description of the present invention, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions may unnecessarily obscure the essence of the invention. Embodiments of the present invention will be described below with reference to the attached drawings.

[0032] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present invention is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0033] For convenience of explanation, the present invention uses terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard. However, the present invention is not limited by the above terms and names and can be applied equally to systems conforming to other standards. In the present invention, eNB may be used interchangeably with gNB for convenience of explanation. That is, a base station described as eNB may represent a gNB.

[0034] FIG. 1 illustrates the structure of an LTE system according to one embodiment of the present invention.

[0035] Referring to FIG. 1, as illustrated, the wireless access network of the LTE system consists of a next-generation base station (Evolved Node B, hereinafter ENB, Node B or base station) (105, 110, 115, 120), a Mobility Management Entity (MME) (125), and an S-GW (130, Serving-Gateway). A user terminal (User Equipment, hereinafter UE or terminal) (135) connects to an external network through the ENB (105~120) and the S-GW (130).

[0036] In FIG. 1, the ENBs (105–120) correspond to the existing Node B of the UMTS system. The ENBs are connected to the UE (135) via a wireless channel and perform more complex roles than the existing Node B. In an LTE system, since all user traffic, including real-time services such as VoIP (Voice over IP) via the Internet Protocol, is serviced through a shared channel, a device is required to collect status information such as the buffer status, available transmission power status, and channel status of the UEs to perform scheduling, and this is handled by the ENBs (105–120). A single ENB typically controls multiple cells. For example, to achieve a transmission speed of 100 Mbps, the LTE system uses Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as a wireless access technology, for example, in a 20 MHz bandwidth. In addition, an Adaptive Modulation & Coding (hereinafter referred to as AMC) method is applied to determine the modulation scheme and channel coding rate according to the channel conditions of the terminal. The S-GW (130) is a device that provides data bearers and creates or removes data bearers according to the control of the MME (125). The MME is a device that is responsible for various control functions as well as mobility management functions for the terminal and is connected to multiple base stations.

[0037] FIG. 2 illustrates a wireless protocol structure in an LTE system according to one embodiment of the present invention.

[0038] Referring to FIG. 2, the wireless protocol of the LTE system consists of PDCP (Packet Data Convergence Protocol 205, 240), RLC (Radio Link Control 210, 235), and MAC (Medium Access Control 215, 230) at the terminal and ENB, respectively. PDCP (Packet Data Convergence Protocol) (205, 240) is responsible for operations such as IP header compression / decompression. The main functions of PDCP are summarized as follows.

[0039] - Header compression and decompression features (ROHC only)

[0040] - User data transfer function (Transfer of user data)

[0041] - Sequential delivery function (In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM)

[0042] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0043] - Duplicate detection function (Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

[0044] - Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of ​​PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

[0045] - Encryption and decryption functions (Ciphering and deciphering)

[0046] - Timer-based SDU discard in uplink.

[0047] Radio Link Control (hereinafter referred to as RLC) (210, 235) reconstructs PDCP Packet Data Units (PDUs) into an appropriate size to perform ARQ operations, etc. The main functions of RLC are summarized as follows.

[0048] - Data transfer function (Transfer of upper layer PDUs)

[0049] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0050] - Concatenation, segmentation, and reassembly functions (Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transfer))

[0051] - Re-segmentation function (Re-segmentation of RLC data PDUs (only for AM data transfer))

[0052] - Reordering function (Reordering of RLC data PDUs (only for UM and AM data transfer)

[0053] - Duplicate detection function (only for UM and AM data transfer)

[0054] - Error detection function (Protocol error detection (only for AM data transfer))

[0055] - RLC SDU deletion function (RLC SDU discard (only for UM and AM data transfer))

[0056] RLC re-establishment function

[0057] MAC (215, 230) is connected to multiple RLC layer devices configured in a terminal and performs the operation of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

[0058] - Mapping function (Mapping between logical channels and transport channels)

[0059] - Multiplexing and demultiplexing function (Multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels)

[0060] - Scheduling information reporting function

[0061] - HARQ function (Error correction through HARQ)

[0062] - Priority handling between logical channels of one UE

[0063] - Priority handling between UEs by means of dynamic scheduling

[0064] - MBMS service identification

[0065] - Transport format selection function

[0066] - Padding

[0067] The physical layer (220, 225) performs the operation of channel coding and modulating upper layer data, making it into OFDM symbols and transmitting them to the wireless channel, or demodulating OFDM symbols received through the wireless channel and channel decoding them to transmit them to the upper layer.

[0068] FIG. 3 illustrates the structure of a next-generation mobile communication system according to one embodiment of the present invention.

[0069] Referring to FIG. 3, as illustrated, the wireless access network of a next-generation mobile communication system (hereinafter NR or 5G) consists of a next-generation base station (New Radio Node B, hereinafter NR gNB or NR base station) (310) and an NR CN (305, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter NR UE or terminal) (315) connects to an external network through the NR gNB (310) and the NR CN (305).

[0070] In FIG. 3, the NR gNB (310) corresponds to the eNB (Evolved Node B) of the existing LTE system. The NR gNB is connected to the NR UE (315) via a wireless channel and can provide superior service compared to the existing Node B. In the next-generation mobile communication system, since all user traffic is serviced through a shared channel, a device is required to collect state information such as the buffer status, available transmission power status, and channel status of the UEs and perform scheduling, and this is handled by the NR NB (310). A single NR gNB typically controls multiple cells. To achieve ultra-high-speed data transmission compared to current LTE, it can have a bandwidth greater than the existing maximum bandwidth, and additionally, beamforming technology can be incorporated by using Orthogonal Frequency Division Multiplexing (hereinafter referred to as OFDM) as the wireless access technology. In addition, an Adaptive Modulation & Coding (hereinafter referred to as AMC) method is applied to determine the modulation scheme and channel coding rate according to the channel conditions of the terminal. The NR CN (305) performs functions such as mobility support, bearer configuration, and QoS configuration. The NR CN is a device responsible for various control functions as well as mobility management functions for the terminal, and is connected to multiple base stations. Furthermore, the next-generation mobile communication system can be interoperable with the existing LTE system, and the NR CN is connected to the MME (325) via a network interface. The MME is connected to the existing base station eNB (330).

[0071] FIG. 4 illustrates the wireless protocol structure of a next-generation mobile communication system according to one embodiment of the present invention.

[0072] Referring to FIG. 4, the wireless protocol of the next-generation mobile communication system consists of NR SDAP (401, 445), NR PDCP (405, 440), NR RLC (410, 435), and NR MAC (415, 430) at the terminal and the NR base station, respectively.

[0073] The main functions of NR SDAP (401, 445) may include some of the following functions.

[0074] - User data transfer function (transfer of user plane data)

[0075] - Mapping function between a QoS flow and a DRB for both DL and UL for uplink and downlink

[0076] - Marking QoS flow ID in both DL and UL packets for uplink and downlink

[0077] - Function to map reflective QoS flow to data bearers for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0078] For SDAP layer devices, the terminal may receive a setting via an RRC message regarding whether to use the SDAP layer device header or the SDAP layer device functions for each PDCP layer device, bearer, or logical channel. If the SDAP header is configured, the terminal may be instructed to update or reset the mapping information for the uplink and downlink QoS flows and data bearers using the 1-bit NAS reflective QoS and AS reflective QoS indicators in the SDAP header. The SDAP header may include QoS flow ID information indicating QoS. The QoS information may be used for data processing priorities, scheduling information, etc., to support seamless service.

[0079] The main functions of NR PDCP (405, 440) may include some of the following functions.

[0080] Header compression and decompression (ROHC only)

[0081] - User data transfer function (Transfer of user data)

[0082] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0083] - Out-of-sequence delivery of upper layer PDUs

[0084] - Reordering function (PDCP PDU reordering for reception)

[0085] - Duplicate detection function (Duplicate detection of lower layer SDUs)

[0086] - Retransmission of PDCP SDUs

[0087] - Encryption and decryption functions (Ciphering and deciphering)

[0088] - Timer-based SDU discard in uplink.

[0089] The reordering function of the NR PDCP device refers to a function that reorders PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function to transmit data to an upper layer in the reordered order, or a function to transmit immediately without considering the order, may include a function to record lost PDCP PDUs by reordering, may include a function to report the status of lost PDCP PDUs to the transmitting side, and may include a function to request retransmission of lost PDCP PDUs.

[0090] The main functions of NR RLC (410, 435) may include some of the following functions.

[0091] - Data transfer function (Transfer of upper layer PDUs)

[0092] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

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

[0094] - ARQ function (Error Correction through ARQ)

[0095] - Concatenation, segmentation, and reassembly functions of RLC SDUs

[0096] - Re-segmentation function (Re-segmentation of RLC data PDUs)

[0097] - Reordering function (Reordering of RLC data PDUs)

[0098] - Duplicate detection

[0099] - Error detection function (Protocol error detection)

[0100] - RLC SDU discard function

[0101] RLC re-establishment function

[0102] The in-sequence delivery function of an NR RLC device refers to the function of delivering RLC SDUs received from a lower layer to an upper layer in sequence. It may include a function to reassemble and deliver RLC SDUs when a single RLC SDU is received split into multiple RLC SDUs; a function to reorder received RLC PDUs based on an RLC SN (sequence number) or PDCP SN (sequence number); a function to record lost RLC PDUs after reordering; a function to report the status of lost RLC PDUs to the transmitting side; a function to request retransmission of lost RLC PDUs; a function to deliver only the RLC SDUs prior to the lost RLC SDU to the upper layer in sequence if there is a lost RLC SDU; or a function to deliver all RLC SDUs received before the timer started to the upper layer in sequence if a predetermined timer has expired even if there is a lost RLC SDU; or the lost Even if there are RLC SDUs, if a predetermined timer has expired, it may include a function to deliver all RLC SDUs received so far to the upper layer in order. Additionally, RLC PDUs may be processed in the order they are received (e.g., in the order of arrival, regardless of the sequence number) and delivered to the PDCP device out of order (out-of-sequence delivery); in the case of segments, segments stored in a buffer or to be received later may be received, reconstructed into a single complete RLC PDU, processed, and delivered to the PDCP device.The NR RLC layer may not include a concatenation function, and the function may be performed in the NR MAC layer or replaced by the multiplexing function of the NR MAC layer.

[0103] The out-of-sequence delivery function of an NR RLC device refers to the function of delivering RLC SDUs received from a lower layer directly to an upper layer regardless of order. It may include a function of reassembling and delivering RLC SDUs when a single RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs and sorting the order to record the lost RLC PDUs.

[0104] The NR MAC (415, 430) can be connected to multiple NR RLC layer devices configured in a terminal, and the main functions of the NR MAC may include some of the following functions.

[0105] - Mapping function (Mapping between logical channels and transport channels)

[0106] - Multiplexing and demultiplexing functions (Multiplexing / demultiplexing of MAC SDUs)

[0107] - Scheduling information reporting function

[0108] - HARQ function (Error correction through HARQ)

[0109] - Priority handling between logical channels of one UE

[0110] - Priority handling between UEs by means of dynamic scheduling

[0111] - MBMS service identification

[0112] - Transport format selection function

[0113] - Padding

[0114] The NR PHY layer (420, 425) can perform the operation of channel coding and modulating upper layer data, creating OFDM symbols and transmitting them to the wireless channel, or demodulating OFDM symbols received through the wireless channel and channel decoding them to transmit them to the upper layer.

[0115] FIG. 5 illustrates a cell reselection evaluation procedure for a terminal in an RRC idle mode (RRC_IDLE) or RRC disabled state (RRC_INACTIVE) in a next-generation mobile communication system according to an embodiment of the present invention.

[0116] The cell reselection evaluation procedure may refer to a procedure for determining whether to maintain the current serving cell or reselect the cell to a neighbor cell when a terminal in RRC idle mode (RRC_IDLE) or RRC inactive state (RRC_INACTIVE) determines, due to a certain reason or movement, whether to maintain the current serving cell or reselect the cell to a neighbor cell.

[0117] In the case of handover, whether to perform a handover operation is determined by the network (e.g., AMF or source gNB), whereas in the case of cell reselection, the terminal in RRC idle mode or RRC disabled state can determine whether to perform a cell reselection operation itself based on cell measurement values. The cell that the terminal reselects may mean a cell using the same NR frequency as the serving cell currently camp-on (e.g., NR intra-frequency or serving NR frequency), a cell using a different NR frequency from the serving cell (e.g., NR inter-frequency), or a cell on a frequency using a different Radio Access Technology (hereinafter RAT) (e.g., inter-RAT frequency).

[0118] Referring to FIG. 5, the terminal (501) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with an NR cell (502) (503).

[0119] An NR cell (502) may send an RRC disconnection message (RRCRelease) (504) to disconnect the RRC connection with a terminal (501) that is in RRC connection mode. If the message sent by the NR cell includes suspension configuration information (suspendConfig), the terminal may transition to an RRC inactive mode (RRC_INACTIVE) (505). If the message sent by the NR cell does not include suspendConfig, the terminal may transition to an RRC idle mode (RRC_IDLE) (505). The message sent by the NR cell may include cellReselectionPriorities for the terminal to perform cell reselection. cellReselectionPriorities may include at least one value among freqPriorityListEUTRA, freqPriorityListNR, and t320. If the value t320 is included in cellReselectionPriorities, the terminal may drive the T320 timer with that value. Specifically, the configuration information included in the above RRCRelease message may be as shown in Table 1 below.

[0120]

[0121]

[0122]

[0123] In step 513, a terminal (501) in RRC idle mode or RRC disabled state can obtain essential system information from an NR cell (502). In this disclosure, Master Information Block (MIB) and System Information Block 1 (SIB1) may be referred to as essential system information.

[0124] In step 515, a terminal (501) in an RRC idle mode or RRC inactive state can perform a cell selection procedure based on the essential system information obtained in step 513. That is, the terminal can find an NR suitable cell belonging to a selected PLMN (Public Land Mobile Network) or SNPN (Standalone Non-Public Network) and camp on to that cell. The cell camped on by the terminal may be referred to as a serving cell. In this disclosure, based on the 3GPP standard document "38.304: User Equipment (UE) procedures in Idle mode and RRC Inactive state," a cell may be defined as a suitable cell if the conditions of Table 2 below are satisfied.

[0125]

[0126] For reference, the terminal can determine that the cell selection criteria are fulfilled if the following mathematical formula 1 is satisfied.

[0127] [Mathematical Formula 1]

[0128]

[0129]

[0130] In step 520, a terminal (501) in an RRC idle mode or RRC disabled state may obtain system information (e.g., SIB2, SIB3, SIB4, SIB5) containing cell reselection information from a serving cell (502) to perform a cell reselection evaluation procedure. SIB2 may include NR intra-frequency cell reselection information excluding information / parameters commonly applied to the RRC terminal for reselecting NR intra-frequency, NR inter-frequency, and inter-RAT frequency cells, and information related to NR intra-frequency surrounding cells. For example, SIB2 may include one cell reselection priority setting information for a serving NR frequency (e.g., the frequency to which the currently camp-on cell belongs). The cell reselection priority setting information may refer to cellReselectionPriority and cellReselectionSubPriority. Specifically, cellReselectionPriority includes an integer value (e.g., an integer value from 0 to 7), and cellReselectionSubPriority may include a decimal value (e.g., a decimal value from 0.2, 0.4, 0.6, or 0.8). If both cellReselectionPriority and cellReselectionSubPriority are signaled, the terminal may add the two values ​​to derive a cell reselection priority value. For reference, a larger cell reselection priority value may indicate a higher priority, but is not limited thereto. Specifically, the cell reselection setting information broadcast on SIB2 may be as shown in Table 3 below.

[0131]

[0132]

[0133] SIB3 may include neighboring cell information / parameters for a terminal in RRC idle mode or RRC disabled state to re-select an NR intra-frequency cell. For example, via SIB3, an NR intra-frequency cell list (intraFreqNeighCellList), a list of cells for which NR intra-frequency cell re-selection is allowed (intraFreqAllowedCellList), and a list of cells for which NR intra-frequency cell re-selection is not allowed (intraFreqExcludedCellList) may be broadcast. Specifically, SIB3 may broadcast the information in Table 4 below.

[0134]

[0135] SIB4 may include information / parameters for a terminal in RRC idle mode or RRC disabled state to reselect an NR inter-frequency cell. For example, SIB4 may broadcast one or more NR inter-frequencies and may broadcast one cell reselection priority setting information for each NR inter-frequency. The cell reselection priority setting information for each NR inter-frequency refers to the contents described above (e.g., cellReselectionPriority and / or cellReselectionSubPriority mapped to each NR inter-frequency), but may include the feature that one cell reselection priority setting information for each inter-frequency is broadcast optionally. Specifically, the information in Table 5 below may be broadcast via SIB4.

[0136]

[0137]

[0138] SIB5 may include information / parameters for a terminal in RRC idle mode or RRC disabled state to reselect an inter-RAT frequency cell. For example, SIB5 may broadcast one or more EUTRA frequencies and may broadcast one cell reselection priority setting information for each EUTRA frequency. The cell reselection priority setting information for each EUTRA frequency refers to the contents described above (e.g., cellReselectionPriority and / or cellReselectionSubPriority mapped to each EUTRA frequency), but may include the feature that one cell reselection priority setting information for each EUTRA frequency is broadcast optionally. Specifically, the information in Table 6 below may be broadcast via SIB5.

[0139]

[0140]

[0141] A terminal in RRC idle mode or an RRC disabled state can perform a cell reselection evaluation process. The cell reselection evaluation process may refer to a series of processes that perform frequency measurements by handling reselection priorities and applying measurement rules for cell reselection, and reselect a cell by evaluating cell reselection criteria.

[0142] In step 525, a terminal in RRC idle mode or RRC disabled state can determine reselection priority based on the RRC release message received in step 504 or system information received in step 520. If the RRC release message received in step 504 includes cellReselectionPriorities, and cellReselectionPriorities does not have a t320 timer value, or if the t320 timer value is set and the T320 timer is running, the terminal can determine reselection priority according to the RRC release message. That is, if cellReselectionPriorities included in the RRC release message can be applied, the terminal can determine reselection priority according to the RRC release message. If cellReselectionPriorities is not included in the RRC release message or cellReselectionPriorities are disabled, the terminal can determine reselection priority based on the system information received in step 520. A terminal according to the present disclosure can determine, based on a cell reselection priority value mapped to the NR frequency to which the serving cell currently camp-on belongs, whether the cell reselection priority for each NR inter-frequency or inter-RAT frequency has the same cell reselection priority as the NR frequency to which the serving cell belongs, whether it has a higher cell reselection priority than the NR frequency to which the serving cell belongs, or whether it has a lower cell reselection priority than the NR frequency to which the serving cell belongs.For example, in the system information obtained in step 520, if the cell reselection priority value mapped to the NR frequency to which the serving cell currently camp-on belongs is set to 3, the cell reselection priority value of inter NR frequency 1 is set to 2, the cell reselection priority value of inter NR frequency 2 is set to 3, the cell reselection priority value of inter NR frequency 3 is set to 4, and the cell reselection priority value of EUTRA frequency 1 is set to 2, the terminal can determine that inter NR frequency 1 and EUTRA frequency 1 have a lower reselection priority, determine that the cell reselection priority of inter NR frequency 2 has an equal reselection priority, and determine that the cell reselection priority of inter NR frequency 3 has a higher reselection priority.

[0143] In step 530, a terminal in RRC idle mode or RRC disabled state may perform frequency measurement for cell reselection. At this time, to minimize battery consumption, the terminal may perform frequency measurement using the following measurement rule according to the cell reselection priority determined in step 525.

[0144] - The above terminal may not perform NR intra-frequency measurement if the following condition 1 is satisfied. Otherwise (for example, if the following condition 1 is not satisfied), the terminal may perform NR intra-frequency measurement.

[0145] Condition 1: The receiving level (S_rxlev) of the serving cell is greater than the S_IntraSearchP threshold and the receiving quality (S_qual) of the serving cell is greater than the S_IntraSearchQ threshold (Serving cell fulfils S_rxlev > S_IntraSearchP and S_qual > S_IntraSearchQ).

[0146] - For NR inter-frequency or inter-RAT frequency that has a higher reselection priority than the NR frequency of the current serving cell, the terminal can perform measurements in accordance with the 3GPP TS 38.133 standard.

[0147] - For NR inter-frequencies with a reselection priority lower than or equal to the NR frequency of the current serving cell and inter-RAT frequencies with a reselection priority lower than the NR frequency of the current serving cell, the terminal may not perform a measurement if Condition 2 below is satisfied. Otherwise (for example, if Condition 2 below is not satisfied), the terminal may measure cells in NR inter-frequencies with a reselection priority lower than or equal to the NR frequency, or measure cells in inter-RAT frequencies with a reselection priority lower than the NR frequency.

[0148] Condition 2: The receiving level (S_rxlev) of the serving cell is greater than the S_nonIntraSearchP threshold and the receiving quality (S_qual) of the serving cell is greater than the S_nonIntraSearchQ threshold (Serving cell fulfils S_rxlev > S_nonIntraSearchP and S_qual > S_nonIntraSearchQ).

[0149] For reference, the aforementioned threshold values ​​(SintraSearchP, SintraSearchQ, SnonIntraSearchP, SnonintraSearchQ) can be broadcast from the system information obtained in step 520.

[0150] If the terminal supports relaxed measurement and relaxedMeasurement exists in SIB2, the terminal can relax the necessary measurements according to the above description in accordance with the contents of Table 7 below.

[0151]

[0152]

[0153]

[0154] For reference, the terminal (501) can measure the SS-RSRP (Synchronization Signal based Reference Signal Received Power) level and SS-RSRQ (Synchronization Signal based Reference Signal Received Quality) level for the serving cell at least once every M1*N1DRX cycle and evaluate the cell selection criteria (S criterion) of the above-described embodiment. The values ​​for M1 and N1 can be determined by the following Table 8.

[0155]

[0156] In step 535, a terminal in RRC idle mode or RRC disabled state may decide to reselect a cell that satisfies the cell reselection criteria based on the measurement values ​​performed in step 530. Different criteria may be applied to the cell reselection criteria depending on the cell reselection priority. If multiple cells satisfying the cell reselection criteria have different cell reselection priorities, reselecting a frequency / RAT cell with a higher priority may take precedence over reselecting a frequency / RAT cell with a lower priority (Cell reselection to a higher priority RAT / frequency shall take precedence over a lower priority RAT / frequency if multiple cells of different priorities fulfil the cell reselection criteria). Specifically, the terminal's behavior regarding the reselection criteria for inter-frequency / inter-RAT cells that have a higher priority than the frequency of the currently serving cell is as follows.

[0157] - 1st operation:

[0158] If SIB2 broadcasts a threshold value for threshServingLowQ, and 1 second has passed since the terminal camped on to the current serving cell, and the signal quality (Squal) of the inter-frequency / inter-RAT cell is greater than the threshold ThreshX,HighQ during a specific time interval TreselectionRAT (Squal > ThreshX,HighQ during a time interval TreselectionRAT), the terminal can perform reselection to the corresponding inter-frequency / inter-RAT cell.

[0159] - Second operation:

[0160] If the terminal is unable to perform the first operation, it may perform the second operation.

[0161] If 1 second has passed since the terminal camped on to the current serving cell, and the reception level (Srxlev) of the inter-frequency / inter-RAT cell is greater than the threshold ThreshX,HighP during a specific time interval TreselectionRAT (Srxlev > ThreshX, HighP during a time interval TreselectionRAT), the terminal can perform reselection to the corresponding inter-frequency / inter-RAT cell.

[0162] Here, the terminal may perform a first or second operation based on information contained in SIB4 broadcast from the serving cell regarding the signal quality (Squal), reception level (Srxlev), threshold values ​​(ThrehX, HighQ, ThreshX, HighP), and TreselectionRAT values ​​of the inter-frequency cell. Alternatively, the terminal may perform a first or second operation based on information contained in SIB5 broadcast from the serving cell regarding the signal quality (Squal), reception level (Srxlev), threshold values ​​(ThreshX, HighQ, ThreshX, HighP), and TreselectionRAT values ​​of the inter-RAT cell. For example, SIB4 may contain Qqualmin values ​​or Qrxlevmin values, and based thereon, the signal quality (Squal) or reception level (Srxlev) of the inter-frequency cell can be derived. If there are multiple cells in the NR frequency that satisfy the high cell reselection priority, the terminal can reselect the cell to the highest-ranked cell among the cells that satisfy the reselection criteria for intra-frequency / inter-frequency cells that have the same priority as the frequency of the currently serving cell.

[0163] In addition, the terminal's operation regarding the reselection criteria for intra-frequency / inter-frequency cells having the same priority as the current serving cell's frequency is as follows.

[0164] - Third operation:

[0165] The terminal can derive a cell-specific rank based on the measured value (RSRP) when the signal quality (Squal) and reception level (Srxlev) of the intra-frequency / inter-frequency cell are greater than 0 (The UE shall perform ranking of all cells that fulfills the cell selection criterion S). The ranks of the serving cell and surrounding cells are calculated respectively through the following Equation 2.

[0166] [Mathematical Formula 2]

[0167]

[0168] Here, Q_meas,s is the RSRP measurement of the serving cell, Q_meas,n is the RSRP measurement of the surrounding cell, Q_hyst is the hysteresis value of the serving cell, and Q_offset is the offset between the serving cell and the surrounding cell. The Q_hyst value is included in SIB2, and this value can be used commonly for intra-frequency / inter-frequency cell reselection. For intra-frequency cell reselection, Q_offset is signaled per cell and applies only to the designated cell, and can be included in SIB3. For inter-frequency cell reselection, Q_offset is signaled per cell and applies only to the designated cell, and can be included in SIB4. The terminal can reselect the optimal cell among the surrounding cells when the Rank of the surrounding cell obtained from Equation 2 is greater than the Rank of the serving cell (e.g., R_n > R_s).

[0169] Here, Q_offsettemp is an offset temporarily applied to the cell, which may refer to the connEstFailOffset included in ConnEstFailureControld broadcast from SIB1, and may be applied upon RRC connection failure (e.g., when the T300 timer expires).

[0170] In addition, the terminal's operation regarding the reselection criteria for inter-frequency / inter-RAT cells with a lower priority than the frequency of the current serving cell is as follows.

[0171] - 4th Action:

[0172] If SIB2 broadcasts a threshold value for threshServingLowQ, and 1 second has passed since the terminal camped on to the current serving cell, and the signal quality (Squal) of the current serving cell is less than the threshold value (ThreshServing, LowQ) (Squal < ThreshServing, LowQ), and the signal quality (Squal) of the inter-frequency / inter-RAT cell is greater than the threshold value (ThreshX, LowQ) during a specific time interval TreselectionRAT (e.g., Squal > ThreshX, LowQ during a time interval TreselectionRAT), the terminal can perform reselection to the corresponding inter-frequency / inter-RAT cell.

[0173] - Fifth Action:

[0174] If the terminal is unable to perform the fourth operation, it may perform the fifth operation.

[0175] If 1 second has passed since the terminal camped on to the current serving cell, and the reception level (Srxlev) of the current serving cell is less than the threshold value (ThreshServing, LowP) (e.g., Srxlev < ThreshServing, LowP), and the reception level (Srxlev) of the inter-frequency / inter-RAT cell is greater than the threshold value (ThreshX, LowQ) during a specific time interval TreselectionRAT (e.g., Srxlev > ThreshX,LowP during a time interval TreselectionRAT), the terminal can perform reselection to the corresponding inter-frequency / inter-RAT cell.

[0176] A fourth or fifth operation for an inter-frequency cell of the terminal may be performed based on the threshold values ​​(ThreshServing, LowQ, ThreshServing, LowP) included in SIB2 broadcast from the serving cell, and the signal quality (Squal), reception level (Srxlev), threshold values ​​(ThrehX, LowQ, ThreshX, LowP), and TreselectionRAT of the inter-frequency cell included in SIB4 broadcast from the serving cell. A fourth or fifth operation for an inter-RAT cell of the terminal may be performed based on the threshold values ​​(ThreshServing, LowQ, ThreshServing, LowP) included in SIB2 broadcast from the serving cell, and the signal quality (Squal), reception level (Srxlev), threshold values ​​(ThreshX, LowQ, ThreshX, LowP), and TreselectionRAT of the inter-RAT cell included in SIB5 broadcast from the serving cell. For example, SIB4 includes Qqualmin values ​​or Qrxlevmin values, and the terminal can derive the signal quality (Squal) or reception level (Srxlev) of the inter-frequency cell based on this. If there are multiple cells in the NR frequency that satisfy the high cell reselection priority, the terminal can reselect the highest-ranked cell among the cells that satisfy the reselection criteria for intra-frequency / inter-frequency cells that have the same priority as the frequency of the currently serving cell.

[0177] In step 540, a terminal in an RRC idle mode or RRC disabled state may receive system information (e.g., MIB or SIB1) broadcast from a candidate target cell before finally re-selecting a candidate target cell, and based on the received system information, determine whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell satisfy a cell selection criterion referred to as an S-criterion (e.g., Equation 1) (e.g., Srxlev > 0 AND Squal > 0). If the reception level and reception quality of the candidate target cell satisfy Equation 1 and the candidate target cell is suitable, the terminal may re-select the candidate target cell.

[0178] FIG. 6 illustrates a procedure in which a terminal performs an RRC connection establishment procedure with a base station according to an embodiment of the present invention to switch from an RRC idle mode (RRC_IDLE) to an RRC connected mode (RRC_CONNECTED).

[0179] Referring to FIG. 6, a terminal (601) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with a base station (602) (605). If a terminal transmitting and receiving data in the RRC connection mode does not transmit or receive data for a certain reason or for a certain period of time, the base station may transmit an RRC disconnection message (RRCRelease message) that does not include suspend configuration information (suspendConfig) to cause the terminal to switch to an RRC idle mode (RRC_IDLE) (610). A terminal that has transitioned to the RRC idle mode (611) can find a suitable cell and camp on it through a cell selection procedure and / or a cell re-selection procedure to receive system information (615).

[0180] The terminal (601) may perform a Random Access procedure to establish an RRC connection with the base station (602). When Random Access is triggered (616), the terminal may select a PRACH occasion and transmit a Random Access Preamble to the base station (620). Upon receiving the Random Access Preamble, the base station may transmit a Random Access Response (hereinafter RAR) message to the terminal (625). The terminal (601), which is in RRC idle mode, may establish a reverse transmission synchronization with the base station (602) through steps 620 and 625.

[0181] A terminal (601) in an RRC idle mode that has established reverse transmission synchronization can perform an RRC connection establishment procedure with a base station (602). The terminal can drive a T300 timer and initiate the transmission of an RRC connection establishment request message (RRCSetupRequest message) to send the RRC connection establishment request message to the base station (630). The message may include the terminal's identifier (ue-Identity) and the reason for establishing the RRC connection (establishmentCause). Upon receiving the RRC connection establishment request message, the base station may send an RRC connection establishment message (RRCSetup message) to the terminal (635). The message may include radiobearer configuration information and master cell group configuration information (masterCellGroup). Specifically, the wireless bearer configuration information and master cell group configuration information may include information involving an SRB1 (Signaling Radio Bearer 1) connection, RLC bearer configuration information for SRB1, MAC cell group configuration information (mac-CellGroupConfig), physical cell group configuration information (physicalCellGroupConfig), etc. That is, the establishment of an RRC connection may involve an SRB1 connection and may not involve other wireless bearer connections excluding SRB1 (for example, it does not involve an SRB2 for transmitting and receiving NAS messages between the terminal and the base station or a DRB (Data Radio Bearer) connection for transmitting and receiving data). When an RRC connection configuration message is received, the terminal may apply the above information and switch to an RRC connection mode (636). The terminal that has switched to an RRC connection mode may transmit an RRC connection setup completion message (RRCSetupComplete message) to the base station via SRB1 (640).The message transmitted by the terminal may include a service request message in which the terminal requests a bearer setting for a specific service from an AMF (Access Management Function) or MME (Mobility Management Entity).

[0182] If the RRC connection establishment procedure is successfully performed, the base station (602) may send a SecurityModeCommand message to the terminal (601) in RRC connection mode to activate AS Security (645). Upon receiving the SecurityModeCommand message, the terminal may send a SecurityModeComplete message to the base station (650).

[0183] The base station (602) may perform an RRC reconfiguration procedure with the terminal (601) when transmitting a security mode command message, after transmitting the security mode command message, or after receiving the security mode completion message. First, the base station may transmit an RRC reconfiguration message to the terminal (655). The message may include some or all of the following information.

[0184] - Directive (fullConfig) indicating whether to apply full configuration information

[0185] - Radio Bearer Configuration Information (radioBearerConfig): radioBearerConfig may include at least one of the following information.

[0186] * SRB list to be added or modified (srb-ToAddModList): srb-ToAddModList may include one or more SRB configuration information (SRB-ToAddMod), and each SRB-ToAddMod may include an SRB identifier (srb-Identity), an indicator (reestablishmentPDCP) indicating whether to re-establish PDCP, an indicator indicating whether to discard Service Data Units (SDU) and Protocol Data Units (PDU) stored in the terminal, or PDCP configuration information (pdcp-Config).

[0187] * Indicator for whether to release SRB3 (srb3-ToRelease): SRB3 can be released only through SRB1. SRB3 can be released only when releasing the Secondary Cell Group (hereinafter SCG) configured for the terminal and / or by reconfiguration with sync.

[0188] * DRB list to be added or modified (drb-ToAddModList): drb-ToAddModList may contain one or more DRB configuration information (DRB-ToAddMod), and each DRB-ToAddMod may contain a DRB identifier (drb-Identity), an indicator indicating whether to re-establish PDCP (reestablishmentPDCP), an indicator indicating whether to perform a recovery procedure on PDCP (recoverPDCP), PDCP configuration information (pdcp-Config), or information indicating whether the bearer is associated with eps-bearerIdentity or SDAP configuration information (sdap-Config) (cnAssociation). cnAssociation may include eps-BearerIdentity if connected to EPC, or sdap-Config if connected to 5GC.

[0189] * List of DRBs to be released (drb-ToReleaseList): drb-ToReleaseList may include one or more DRB identifiers (DRB-Identity) to be released.

[0190] * Security Configuration Information (securityConfig): securityConfig may include information indicating whether to use a master key (e.g., a key for a Master Cell Group (MCG)) or a secondary key (e.g., a key for an SCG) to derive a key for security algorithm configuration information (SecurityAlgorithmConfig) or for ciphering and / or integrity protection.

[0191] - Master cell group configuration information (masterCellGroup): masterCellGroupConfig may include at least one of the following information.

[0192] * Information that identifies a cell group (cellGroupId): CellGroupId can be indicated by a single value. For example, if indicated by 0, it may represent MCG, and if indicated by another value, it may represent SCGs.

[0193] * List of RLC bearer configuration information to be added or modified (rlc-BearerToAddModList): rlc-BearerToAddModList may contain one or more RLC bearer configuration information (RLC-BearerConfig), and each RLC-BearerConfig may include a logical channel identifier (logicalChannelIdentity), an SRB identifier (srb-Idendity) or DRB identifier (drb-Identity) associated with the RLC bearer, an indicator (reestablishRLC) indicating whether the RLC needs to be re-established, RLC configuration information (rlc-Config), or MAC-LogicalChannelConfig containing logical channel information.

[0194] * List of RLC bearer configuration information to be released (rlc-BearerToReleaseList): May include one or more logicalChannelIdentities associated with the RLC bearer to be released.

[0195] MAC Cell Group Configuration Information (mac-CellGroupConfig)

[0196] * PHYSICAL cell group configuration information (physical-CellGroupConfig)

[0197] * Configuration information for SpCell (spCellConfig): spCellConfig may include an index (servCellIndex) for identifying SpCell (meaning Primary Cell (PCell) of MCG or Primary SCG Cell (PSCell) of SCG), parameters for synchronous reconfiguration in the target SpCell (reconfigurationWithSync), information on whether to set or disable parameters containing timer values ​​and constant values ​​for detecting and triggering cell-level wireless link failure (rlf-TimerAndConstants), rlmInSyncOutOfSyncThreshold, or spCellConfigDedicated.

[0198] List of SCell setting information to add or modify (sCellToAddModList)

[0199] * List of SCell settings to be released (sCellToReleaseList)

[0200] * Measurement configuration information (measConfig)

[0201] * Master Key configuration information to update (masterKeyUpdate): masterKeyUpdate may include keySetChangeIndicator, nextHopChainingCount, or nas-Container. masterKeyUpdate must always be included when an RRC connection reconfiguration procedure is performed due to a handover that requires changing the security algorithm, and may be optionally included if ReconfigurationWithSync is included in other cases.

[0202] The above-described message may additionally include dedicatedNAS-MessageList, dedicatedSIB1-Delivery, dedicatedSystemInformationDelivery, or otherConfig. A terminal that receives an RRC connection reconfiguration message may apply the above-described information and then send an RRC connection reconfiguration complete message (RRCReconfigurationComplete message) to the base station (660).

[0203] FIG. 7 illustrates a procedure in which a terminal performs an RRC connection resume procedure with a base station according to an embodiment of the present invention to switch from an RRC inactive mode (RRC_INACTIVE) to an RRC connected mode (RRC_CONNECTED).

[0204] Referring to FIG. 7, a terminal (701) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with a base station (702) (705). If a terminal transmitting and receiving data in the RRC connection mode does not perform data transmission or reception for a certain reason or for a certain period of time, the base station may control the terminal to switch to an RRC disable mode (RRC_INACTIVE) by transmitting an RRC disconnection message (RRCRelease message) including suspendConfig information (710). A terminal that has transitioned to the RRC disable mode (711) can find a suitable cell and camp on it to receive system information through a cell selection procedure and / or a cell re-selection procedure (715).

[0205] The terminal (701) may perform a Random Access procedure to resume an RRC connection with the base station (702). When Random Access is triggered (716), the terminal may select a PRACH occasion and send a Random Access Preamble to the base station (720). Upon receiving the Random Access Preamble, the base station may send a Random Access Response (hereinafter RAR) message to the terminal (725). The terminal (701), which is in an RRC disabled mode, may establish a reverse transmission synchronization with the base station (702) through steps 720 and 725.

[0206] A terminal (701) in an RRC disabled mode that has established reverse transmission synchronization can perform an RRC connection resume procedure with a base station (702). The terminal can drive a T319 timer and initiate the transmission of an RRC connection resume request message or an RRC connection resume request 1 message to the base station (730). The RRC connection resume request message or the RRC connection resume request 1 message may include the terminal's identifier (resumeIdentity) for reclaiming the terminal context from the base station, resume encryption information (resumeMAC-I), and the reason for resuming the RRC connection (resumeCause). Upon receiving the RRC connection resume request message or the RRC connection resume request 1 message, the base station may transmit an RRC connection resume message (RRCResume message) to the terminal (735). The message transmitted by the base station may include radio bearer configuration information (radioBearerConfig), master cell group configuration information (masterCellGroup), measurement configuration information (measConfig), etc. Specifically, the radio bearer configuration information and master cell group configuration information may include configuration information for one or more SRBs (Signaling Radio Bearers) to be resumed, configuration information for one or more DRBs (Data Radio Bearers), RLC bearer configuration information, MAC cell group configuration information (mac-CellGroupConfig), physical cell group configuration information (physicalCellGroupConfig), etc. When an RRC connection resumption message is received, the terminal may apply the received information and switch to RRC connection mode (736).A terminal that has switched to RRC connection mode can send an RRC connection resumption completion message (RRCResumeComplete message) to the base station via SRB1 (740).

[0207] After successfully performing the RRC connection resumption procedure, the base station (702) can perform the RRC connection reconfiguration procedure with the terminal (701). First, the base station (702) can transmit an RRC connection reconfiguration message to the terminal (745). The message transmitted by the base station may include some or all of the following information.

[0208] - Directive (fullConfig) indicating whether to apply full configuration information

[0209] - Radio Bearer Configuration Information (radioBearerConfig): radioBearerConfig may include at least one of the following information.

[0210] * SRB list to be added or modified (srb-ToAddModList): srb-ToAddModList may include one or more SRB configuration information (SRB-ToAddMod), and each SRB-ToAddMod may include an SRB identifier (srb-Identity), an indicator (reestablishmentPDCP) indicating whether to re-establish PDCP, an indicator indicating whether to discard Service Data Units (SDU) and Protocol Data Units (PDU) stored in the terminal, or PDCP configuration information (pdcp-Config).

[0211] * Indicator for whether to release SRB3 (srb3-ToRelease): SRB3 can be released only through SRB1. SRB3 can be released only when releasing a secondary cell group configured for the terminal and / or by reconfiguration with sync.

[0212] * DRB list to be added or modified (drb-ToAddModList): drb-ToAddModList may contain one or more DRB configuration information (DRB-ToAddMod), and each DRB-ToAddMod may contain a DRB identifier (drb-Identity), an indicator indicating whether to re-establish PDCP (reestablishmentPDCP), an indicator indicating whether to perform a recovery procedure on PDCP (recoverPDCP), PDCP configuration information (pdcp-Config), or information indicating whether the bearer is associated with eps-bearerIdentity or SDAP configuration information (sdap-Config) (cnAssociation). cnAssociation may include eps-BearerIdentity if connected to EPC and sdap-Config if connected to 5GC.

[0213] * List of DRBs to be released (drb-ToReleaseList): drb-ToReleaseList may include one or more DRB identifiers (DRB-Identity) to be released.

[0214] * Security configuration information (securityConfig): securityConfig may include security algorithm configuration information (SecurityAlgorithmConfig) or information indicating whether to use a master key or a secondary key to derive a key for ciphering and / or integrity protection.

[0215] - Master cell group configuration information (masterCellGroup): masterCellGroupConfig may include at least one of the following information.

[0216] * Information that identifies a cell group (cellGroupId): CellGroupId can be indicated by a single value. For example, if indicated by 0, it may represent MCG, and if indicated by another value, it may represent SCGs.

[0217] * List of RLC bearer configuration information to be added or modified (rlc-BearerToAddModList): rlc-BearerToAddModList may contain one or more RLC bearer configuration information (RLC-BearerConfig), and each RLC-BearerConfig may include a logical channel identifier (logicalChannelIdentity), an SRB identifier (srb-Idendity) or DRB identifier (drb-Identity) associated with the RLC bearer, an indicator (reestablishRLC) indicating whether the RLC needs to be re-established, RLC configuration information (rlc-Config), or MAC-LogicalChannelConfig containing logical channel information.

[0218] * List of RLC bearer configuration information to be released (rlc-BearerToReleaseList): May include one or more logicalChannelIdentities associated with the RLC bearer to be released.

[0219] MAC Cell Group Configuration Information (mac-CellGroupConfig)

[0220] * PHYSICAL cell group configuration information (physical-CellGroupConfig)

[0221] * Configuration information for SpCell (spCellConfig): spCellConfig may include an index to identify the SpCell (servCellIndex), parameters for synchronous reconfiguration in the target SpCell (reconfigurationWithSync), information on whether to set or disable parameters containing timer values ​​and constant values ​​to detect and trigger cell-level wireless link failures (rlf-TimerAndConstants), rlmInSyncOutOfSyncThreshold, or spCellConfigDedicated.

[0222] List of SCell setting information to add or modify (sCellToAddModList)

[0223] * List of SCell settings to be released (sCellToReleaseList)

[0224] * Measurement configuration information (measConfig)

[0225] * Master Key configuration information to update (masterKeyUpdate): masterKeyUpdate may include keySetChangeIndicator, nextHopChainingCount, or nas-Container. masterKeyUpdate must always be included when an RRC connection reconfiguration procedure is performed due to a handover that requires changing the security algorithm, and may be optionally included if ReconfigurationWithSync is included in other cases.

[0226] The above-described message may additionally include dedicatedNAS-MessageList, dedicatedSIB1-Delivery, dedicatedSystemInformationDelivery, or otherConfig. A terminal that receives an RRC connection reconfiguration message may apply the above-described information and then send an RRC connection reconfiguration completion message (RRCReconfigurationComplete message) to the base station (750).

[0227] FIG. 8 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to report a band list supported by the low-power wake-up receiver to a base station.

[0228] A terminal (801) according to one embodiment of the present disclosure may be equipped with a main radio (hereinafter MR) and a low power wake-up receiver (hereinafter LR) to perform a predetermined operation. The MR (802) installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) and an additionally installed LR (803) in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using LR is less than that of MR, the terminal can achieve a power saving effect by turning off MR and using LR under certain conditions, or by performing measurements that MR would otherwise perform through LR. For reference, the state in which the terminal's MR is turned off may be referred to as the ultra-deep-sleep state.

[0229] According to one embodiment of the present disclosure, the supporting band list of the MR (802) and the supporting band list of the LR (803) may be different or the same. Specifically, it may mean at least one of the following.

[0230] The band list supported by the terminal's MR (802) and the band list supported by the terminal's LR (803) may be the same.

[0231] Some of the band lists supported by the terminal's MR (802) can be supported by the terminal's LR (803).

[0232] One or more bands that are not supported by the MR (802) of the terminal can be supported by the LR (803) of the terminal.

[0233] Referring to FIG. 8, the terminal (801) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with an NR base station (805) (810).

[0234] In step 815, the base station (805) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (801) to retrieve terminal radio access capability information (UE radio access capability information).

[0235] In step 820, the terminal (801) can transmit a terminal capability information message (UECapabilityInformation) to the base station (805). The message transmitted by the terminal may include a list of NR bands supported by the MR (802) of the terminal (801) (supportedBandListNR).

[0236] supportedBandListNR may consist of one or more BandNRs. Each BandNR includes a FreqBandIndicatorNR designating an NR frequency band number, and additionally may include additional terminal capability information (e.g., extended cyclic prefix) that the terminal's MR (802) supports in the corresponding NR frequency band. For specific information included in the BandNR, refer to 3GPP technical specification 38.331. The FreqBandIndicatorNR may be represented as an integer value from 1 to 1024 (e.g., INTEGER (1...1024)), and for which NR frequency band number a specific value designates, refer to 3GPP technical specifications 38.101-1, 38.101-2, and 38.101-5.

[0237] A terminal (801) according to one embodiment of the present disclosure may notify a base station (805) of one or more NR bands (i.e., an NR band list) supported by the terminal's LR (803) through the message described above. Specifically, a method is described in which the terminal includes the NR band list supported by the terminal's LR (803) in the message described above by at least one of the following methods.

[0238] Method 1: When a specific NR frequency band supported by the terminal's MR (802) is also supported by the terminal's LR (803), an indicator (e.g., LP-WUSReception) indicating that the terminal's LR (803) also supports the corresponding NR frequency band may be included within the BandNR supported by the terminal's MR (802). When notifying the base station that both the terminal's MR and LR support a specific NR frequency band, Method 1 requires fewer bits compared to methods that include FreqBandIndicatorNR information additionally or redundantly, because it includes FreqBandIndicatorNR information only once in the BandNR and only additionally introduces the indicator. Therefore, when some of the NR band lists supported by the terminal's MR (802) are supported by the terminal's LR (803), the above method can be very effective in terms of signaling. For example, using Abstract Syntax Notation One (ASN.1) for Method 1, it can be expressed as shown in Table 9 below.

[0239]

[0240] Method 2: The list of NR bands supported by the LR (803) of the terminal is composed of a parallel list having the same number of entries and the same order as the list of NR bands supported by the MR (802) of the terminal, and each entry may include an indicator or information (e.g., LP-WUSReception) indicating whether the NR band supported by the MR of the terminal is also supported by the LR of the terminal. For example, if the list of NR bands supported by MR consists of Band 1, Band 2, and Band 3, and the list of NR bands supported by LR consists of Band 2 and Band 3, the list of NR bands supported by LR consists of three entries, the first entry may include information that Band 1 is not supported by LR (e.g., if there is no LP-WUSReception indicator), the second entry may include information that Band 2 is supported by LR (e.g., if there is an LP-WUSReception indicator), and the third entry may include information that Band 3 is supported by LR (e.g., if there is an LP-WUSReception indicator). Method 2 requires bits indicating the size of the number of NR bands supported by the MR (for reference, Method 1 does not require bits for size, but requires 3 bytes per BandNR, i.e., 24 bits). Therefore, Method 2 can be very effective signalingly when the terminal's LR (803) supports only a very small portion of the list of NR bands supported by the terminal's MR (802). For example, using Abstract Syntax Notation One (ASN.1) for Method 2, it can be expressed as shown in Table 10 below.

[0241]

[0242] Method 3: The list of NR bands supported by the terminal's LR (803) is configured independently of the list of NR bands supported by the terminal's MR (802), and each entry may contain information on the NR bands supported by the LR (BandNR-LR). Method 3 includes a FreqBandIndicatorNR in BandNR-LR that designates the NR frequency band number, and additionally, may include additional terminal capability information (e.g., an extended cyclic prefix) that the terminal's LR (803) supports in the corresponding NR frequency band. Method 3 can be signaling effective because, when one or more specific NR bands are supported only in the LR, the list of NR bands supported by the LR (803) is configured independently of the MR, and for each NR band, only the capabilities supported only in the LR need to be additionally defined. For example, if Abstract Syntax Notation One (ASN.1) for Method 3 is used, it can be expressed as shown in Table 11 below.

[0243]

[0244] Method 4: An indicator may be included indicating that the NR band list supported by the terminal’s MR (802) and the NR band list supported by the terminal’s LR (803) are identical. Method 4 may include an explicit indicator, or other capability information associated with the terminal’s LR (e.g., whether LR is supported, an indicator indicating whether there is a capability to perform relaxed measurement on serving cells and / or surrounding cells depending on LR support, an indicator indicating whether there is a capability to replace the serving cell measurement derived from the LR with the serving cell measurement of the MR (i.e., offloading of serving cell measurement from MR to LR)) and, if no additional NR band list information is provided, an implicit method indicating that the NR band list supported by the terminal’s MR (802) and the NR band list supported by the terminal’s LR (803) are identical may be included.

[0245] FIG. 9 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention, which determines a predetermined frequency as the highest reselection priority to perform a cell reselection procedure and triggers a random access procedure in a reselected cell.

[0246] More specifically, FIG. 9 is a diagram illustrating a procedure in which, when a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention triggers a random access procedure to perform an RRC connection establishment procedure or an RRC connection resume procedure, a predetermined frequency is determined as the highest reselection priority to perform a cell reselection procedure, and a random access procedure is triggered or initiated in the reselected cell to perform an RRC connection establishment procedure or an RRC connection resume procedure.

[0247] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels are provided separately from low-power wake-up signals / channels, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can select or re-select a cell operating at the MR frequency through the terminal's MR and perform a Random Access procedure on the cell. The terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR.For reference, a given cell may be operated simultaneously at MR and LR frequencies, operated only at MR frequencies, or operated only at LR frequencies.

[0248] Referring to FIG. 9, the terminal (901) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (905) (910).

[0249] In step 915, the base station (905) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (901) to retrieve terminal radio access capability information (UE radio access capability information).

[0250] In step 920, the terminal (901) may transmit a terminal capability information message (UECapabilityInformation) to the base station (905). The information included in the message transmitted by the terminal may follow the previously described embodiment (e.g., FIG. 8). A message transmitted by a terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0251] - Information indicating the ability to perform an RRC connection establishment or RRC connection resume procedure by triggering a random access procedure to perform an RRC connection resume procedure in a currently serving cell operating on MR and LR frequencies (e.g., upon receiving a paging message containing a PagingUE-Identity indicating said terminal), without immediately triggering or initiating the random access procedure, determine a specific MR frequency as the highest reselection priority to perform a cell reselection procedure, and trigger or initiate the random access procedure in the reselected cell.

[0252] Here, a predetermined MR frequency may be broadcast to the terminal through system information broadcast by the serving cell or set as an RRC disconnection message (RRCRelease).

[0253] In step 925, the terminal (901) may receive an RRC disconnection message (RRCRelease) from the base station (905). The information included in the message received by the terminal may follow the previously described embodiment (e.g., FIG. 5). The message received by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0254] - An indicator that, when a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), the random access procedure is not triggered or initiated immediately, but is instead triggered or initiated in the cell re-selected through the cell re-selection procedure.

[0255] Here, the cell reselection procedure may mean determining a specific MR frequency, which is broadcast in the system information or set in the RRC disconnection message, as the highest cell reselection priority and performing the procedure.

[0256] - When a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receipt of a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), a predetermined MR frequency for reselecting the cell to trigger or initiate the random access procedure.

[0257] Here, the terminal can determine the highest cell reselection priority during the cell reselection procedure for a predetermined MR frequency.

[0258] - New timer value

[0259] Here, the timer value may refer to a value that determines how much the indicator and / or the predetermined MR frequency is applied. That is, when a new timer value is set, the terminal can drive the timer with that value and perform the operation described above by applying the indicator and / or the predetermined MR frequency while the timer is running. For reference, the timer value may be set together with the indicator and / or the predetermined MR frequency, or only the timer value may be set without the indicator and the predetermined MR frequency. Even if only the timer value is set, the terminal operation can be performed in the same way.

[0260] In step 930, the terminal (901) can apply the received RRC disconnection message and transition to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE).

[0261] In step 935, a terminal (901) in RRC idle mode or RRC disabled mode may perform a cell selection procedure to camp-on to an NR suitable cell (905). This may follow the aforementioned embodiment (e.g., FIG. 5). The cell according to the present disclosure may be operated at MR and LR frequencies. That is, the cell may transmit low-power wake-up signals (hereinafter LP-WUS), or transmit and receive NR signals separate from the low-power wake-ups.

[0262] In step 940, the terminal (901) may obtain system information containing cell reselection information (e.g., SIB2, SIB3, SIB4, SIB5, etc.) from the serving cell (905) to perform a cell reselection evaluation procedure. This may follow the previously described embodiment (e.g., FIG. 5). System information following one embodiment of the present disclosure may, when a random access procedure is triggered for the terminal (901) to establish or resume an RRC connection in the current serving cell (905) (e.g., when a paging terminal identifier (PagingUE-Identity) indicating the terminal is received as a paging message), perform cell reselection by considering a specific MR frequency as the highest reselection priority, and then broadcast specific MR frequency information to trigger or initiate a random access procedure in the reselected cell to perform an RRC connection establishment procedure or an RRC connection resumption procedure. To establish or resume an RRC connection with the cell (905), the terminal may perform a cell reselection evaluation procedure according to the aforementioned embodiment (e.g., FIG. 5) for a specific MR frequency even before the random access procedure is triggered, or may perform the cell reselection evaluation procedure by applying the highest reselection priority (this is to enable rapid reselection of the cell when the random access procedure is triggered). If the cell reselection evaluation procedure is performed by applying the specific MR frequency with the highest reselection priority, the terminal may not reselect a cell at the specific MR frequency before the random access procedure is triggered. The specific MR frequency information may be broadcast through new system information, or it may be broadcast by indicating one of the MR frequencies included in the system information containing existing cell reselection information. Even if the specific MR frequency information is broadcast through new system information, it may also be broadcast by indicating one of the MR frequencies included in the system information containing existing cell reselection information.For convenience of explanation, a specific MR frequency according to one embodiment of the present disclosure may mean NR frequency band 2. If a specific MR frequency is set in an RRC disconnection message, the terminal may apply the specific MR frequency set in the RRC disconnection message instead of applying the specific MR frequency included in the system information.

[0263] In step 945, if a predetermined condition is met, the terminal (901) can turn off the terminal's MR (902) and use the LR (903) to monitor the low-power wake-up signal (hereinafter LP-WUS) transmitted by the cell (905). The predetermined condition may mean that the signal of the serving cell measured from the terminal's MR (e.g., RSRP (Reference Signals Received Power) and / or RSRQ (Reference Signal Received Quality)) is greater than or equal to a predetermined threshold broadcast in the system information, and / or the signal of the serving cell measured from the terminal's LR (RSRP and / or RSRP and / or LP-RSRP (Low-Power RSRP) and / or LP-RSRQ (Low-Power RSRQ)) is greater than or equal to a predetermined threshold broadcast in the system information.

[0264] In step 950, the LR (903) of the terminal (901) may receive the LP-WUS transmitted by the cell (905). The LP-WUS may include information for waking up the terminal (901). The LP-WUS may also include information on whether to monitor the PEI. The LP-WUS may include an indicator that, even if the random access procedure is triggered for the RRC connection establishment procedure or the RRC connection resumption procedure, the terminal (901) does not immediately initiate it, but instead performs cell reselection by considering a specific MR frequency as the highest reselection priority, and then initiates or triggers the random access procedure in the reselected cell.

[0265] In step 955, the terminal (901) can monitor the Paging Early Indication (PEI-O) using the terminal's MR (902). Accordingly, the terminal can receive the PEI (960) transmitted by the cell (905) using the terminal's MR. Steps 955 and 960 may be omitted (for example, if the LP-WUS contains information on whether to omit PEI-O monitoring or if the terminal does not have information on the ability to monitor PEI-O). The PEI may include an indicator that directs the terminal (901) not to immediately initiate a random access procedure for an RRC connection establishment procedure or an RRC connection resumption procedure, but to perform cell reselection by considering a specific MR frequency as the highest reselection priority, and then initiate or trigger a random access procedure in the reselected cell.

[0266] In step 965, the terminal (901) can monitor the Paging Occasion (PO) using the terminal's MR (902). Accordingly, the terminal can receive (970) a Short Message transmitted by the cell (905) using the terminal's MR. The Short Message may include information regarding whether there is a Paging Message. The Short Message may also include an indicator instructing the terminal (901) not to immediately initiate a Random Access Procedure even if it is triggered for an RRC connection establishment procedure or an RRC connection resumption procedure, but to perform cell reselection by considering a specific MR frequency as the highest reselection priority, and then initiate or trigger a Random Access Procedure in the reselected cell.

[0267] In step 975, the terminal (901) can monitor the paging channel using the terminal's MR (902). Accordingly, the terminal can receive a Paging message transmitted by the cell (905) through the terminal's MR (980). The Paging message may include the terminal's identifier (PagingUE-Identity). The Paging message may also include an indicator instructing the terminal (901) not to immediately initiate a random access procedure even if it is triggered for an RRC connection establishment procedure or an RRC connection resumption procedure, but to perform cell reselection by considering a specific MR frequency as the highest reselection priority, and then initiate or trigger a random access procedure in the reselected cell.

[0268] In step 981, the terminal (901) may determine that it needs to perform a random access procedure to switch to an RRC connection mode. For example, the terminal may determine that it needs to perform a random access procedure if the paging message received in step 980 contains a paging terminal identifier (PagingUE-Identity) that identifies the terminal, or if there is a reason to perform an RRC connection establishment procedure or an RRC connection resumption procedure with the base station (e.g., when mobile originated signaling needs to be sent). Note that even if the random access procedure is triggered in step 981, the terminal may not immediately initiate it or may not trigger the random access procedure.

[0269] In step 985, the terminal (901) may perform a cell reselection procedure through the terminal's MR (902) by considering the NR frequency band 2 received in step 925 or step 940 as the highest reselection priority. For reference, the terminal may perform step 980 only due to step 925 and / or step 950 and / or step 960 and / or step 970 and / or step 980.

[0270] In step 990, the terminal (901) can re-select an NR cell (903) operating in NR frequency band 2 through step 985.

[0271] In step 995, the terminal (901) may perform a random access procedure and an RRC connection establishment procedure or an RRC connection resumption procedure with the re-selected NR cell (903). This may follow the embodiments described above (e.g., FIG. 6, FIG. 7).

[0272] FIG. 10 illustrates the flow of another signal for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention, which determines a predetermined frequency as the highest reselection priority to perform a cell reselection procedure and triggers a random access procedure in the reselected cell.

[0273] More specifically, FIG. 10 is a diagram illustrating a procedure in which, when a random access procedure is triggered to perform an RRC connection establishment procedure or an RRC connection resume procedure in a next-generation mobile communication system according to an embodiment of the present invention, a predetermined frequency is determined as the highest reselection priority to perform a cell reselection procedure, and a random access procedure is triggered or initiated in the reselected cell to perform an RRC connection establishment procedure or an RRC connection resume procedure.

[0274] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels are provided separately from low-power wake-up signals / channels, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can select or re-select a cell operating at the MR frequency through the terminal's MR and perform a Random Access procedure on the cell. The terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR.For reference, a given cell may be operated simultaneously at MR and LR frequencies, operated only at MR frequencies, or operated only at LR frequencies.

[0275] Referring to FIG. 10, the terminal (1001) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (1005) (1010).

[0276] In step 1015, the base station (1005) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (1001) to retrieve terminal radio access capability information (UE radio access capability information).

[0277] In step 1020, the terminal (1001) may transmit a terminal capability information message (UECapabilityInformation) to the base station (1005). The information included in the message transmitted by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 8, FIG. 9).

[0278] In step 1025, the terminal (1001) may receive an RRC disconnection message (RRCRelease) from the base station (1005). The information included in the message received by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 5, FIG. 9).

[0279] In step 1030, the terminal (1001) can apply the received RRC disconnection message and transition to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE).

[0280] In step 1035, a terminal (1001) in RRC idle mode or RRC disabled mode may perform a cell selection procedure to camp-on to an NR suitable cell (1005). This may follow the aforementioned embodiment (e.g., FIG. 5). The cell according to the present disclosure may be operated at MR and LR frequencies. That is, the cell may also transmit low-power wake-up signals (hereinafter LP-WUS) and transmit and receive NR signals separate from the low-power wake-ups.

[0281] In step 1040, the terminal (1001) may obtain system information containing cell reselection information (e.g., SIB2, SIB3, SIB4, SIB5, new SIB, etc.) from the serving cell (1005) to perform a cell reselection evaluation procedure. This may follow at least one of the embodiments described above (e.g., FIG. 5, FIG. 9). System information according to one embodiment of the present disclosure may broadcast specific MR frequency information and a cell list for the specific MR frequency, so that when a random access procedure is triggered for the terminal (1001) to establish or resume an RRC connection in the current serving cell (1005) (e.g., when a paging terminal identifier (PagingUE-Identity) indicating the terminal is received as a paging message), the terminal may perform cell reselection by considering a specific MR frequency as the highest reselection priority, and then trigger or initiate a random access procedure in the reselected cell to perform an RRC connection establishment procedure or an RRC connection resumption procedure. A cell list for a specific MR frequency may mean at least one of the following.

[0282] - List of neighbor cells with specific cell reselection parameters

[0283] Here, for each surrounding cell, at least one of the following specific cell reselection parameters may be included.

[0284] {A cell identifier Id (physCellId) capable of identifying a cell, q-RxLevMin (Q to be applied to the cell selection criteria corresponding to Equation 1 described above in FIG. 5 and the cell re-selection criteria corresponding to Equation 2 for deriving Rank rxlevmin ), q-RxLevMinOffsetCell (Q rxlevminoffsetcell ), q-RxLevMinOffsetCellSUL (QrxlevminoffsetcellSUL), q-OffsetCell (Qoffset s,n ), q-QualMin (Q qualmin ), q-QualminOffsetCell (Q qualminoffsetcell ), q-OffsetFreq (Qoffset frequency At least one of )

[0285] - List of neighboring cells that can be considered as candidates for cell reselection (allowed cell list as candidates for cell reselection)

[0286] Here, the surrounding cell list can be defined as a cell identifier range (PCI-Range).

[0287] - Excluded cell list as candidates for cell reselection

[0288] Here, the surrounding cell list can be defined as a cell identifier range (PCI-Range).

[0289] For a specific MR frequency, if a list of surrounding cells containing specific cell reselection parameters is broadcast, the terminal can easily perform reselection to the corresponding surrounding cells. If a list of surrounding cells that can be considered as candidates for cell reselection is broadcast, the terminal can reselect only to those surrounding cells. If a list of surrounding cells that cannot be considered as candidates for cell reselection is broadcast, the terminal can reselect cells excluding those surrounding cells. For reference, if one of the cell lists described above is not broadcast for a specific MR frequency, the terminal can consider all cells at the specific MR frequency as candidates for cell reselection (e.g., the aforementioned embodiment Fig. 9). To establish or resume an RRC connection with the cell (1005), the terminal may perform a cell reselection evaluation procedure according to the aforementioned embodiment (e.g., FIG. 5) for a specific MR frequency and a list of surrounding cells (if configured) even before the random access procedure is triggered, or may perform a cell reselection evaluation procedure by applying the highest reselection priority (this is to enable rapid reselection of the cell when the random access procedure is triggered). If the cell reselection evaluation procedure is performed by applying the specific MR frequency with the highest reselection priority, the terminal may not reselect a cell at the specific MR frequency before the random access procedure is triggered. The specific MR frequency information may be broadcast through new system information, or it may be broadcast by indicating one of the MR frequencies included in the system information containing existing cell reselection information. Even if the specific MR frequency information is broadcast through new system information, the specific MR frequency may be broadcast as one of the MR frequencies included in the system information containing existing cell reselection information.For convenience of explanation, a specific MR frequency according to one embodiment of the present disclosure may refer to NR frequency band 2, and surrounding cells for the specific MR frequency may refer to NR cell z (1006) and NR cell z (1007). If a specific MR frequency is set in an RRC disconnection message, the terminal may not apply the specific MR frequency included in the system information, but may apply the specific MR frequency set in the RRC disconnection message. However, if the specific MR frequency broadcast in the system information and the specific MR frequency set in the RRC disconnection message are the same, the terminal may apply the cell list for the specific MR frequency in the system information when it is broadcast.

[0290] In step 1045, if a predetermined condition is met, the terminal (1001) can turn off the terminal's MR (1002) and use the LR (1003) to monitor the low-power wake-up signal (hereinafter LP-WUS) transmitted by the cell (1005). This may follow the previously described embodiment (e.g., FIG. 9).

[0291] In step 1050, the LR (1003) of the terminal (1001) can receive the LP-WUS transmitted by the cell (1005). This may follow the previously described embodiment (e.g., FIG. 9).

[0292] In step 1055, the terminal (1001) can monitor the Paging Early Indication occasion (PEI-O) using the terminal's MR (1002). Accordingly, the terminal can receive (1060) the PEI transmitted by the cell (1005) using the terminal's MR. Steps 1055 and 1060 may follow the aforementioned embodiment (e.g., FIG. 9).

[0293] In step 1065, the terminal (1001) can monitor the Paging Occasion (PO) using the terminal's MR (1002). Accordingly, the terminal can receive (1070) a Short Message transmitted by the cell (1005) using the terminal's MR. Steps 1065 and 1070 may follow the aforementioned embodiment (e.g., FIG. 9).

[0294] In step 1075, the terminal (1001) can monitor the paging channel using the terminal's MR (1002). Accordingly, the terminal can receive (1080) a Paging message transmitted by the cell (1005) through the terminal's MR. Steps 1075 and 1080 may follow the aforementioned embodiment (e.g., FIG. 9).

[0295] In step 1081, the terminal (1001) may determine that it needs to perform a random access procedure to switch to an RRC connection mode. For example, the terminal may determine that it needs to perform a random access procedure if the paging message received in step 1080 contains a paging terminal identifier (PagingUE-Identity) that identifies the terminal, or if there is a reason to perform an RRC connection establishment procedure or an RRC connection resumption procedure with the base station (e.g., when mobile originated signaling needs to be sent). Note that even if the random access procedure is triggered in step 1081, the terminal may not immediately initiate it or may not trigger the random access procedure.

[0296] In step 1085, the terminal (1001) may perform a cell reselection procedure through the terminal's MR (1002) by considering the NR frequency band 2 received in step 1025 or step 1040 as the highest reselection priority. This may follow the previously described embodiment (e.g., FIG. 9). A terminal following one embodiment of the present disclosure may perform a cell reselection procedure by applying the above-described content in step 1040 when a cell list (1006, 1007) for NR frequency band 2 is broadcast.

[0297] In step 1090, the terminal (1001) can re-select an NR cell (1003) operating in NR frequency band 2 through step 1085.

[0298] In step 1095, the terminal (1001) may perform a random access procedure, an RRC connection establishment procedure, or an RRC connection resumption procedure with the re-selected NR cell (1003). This may follow the embodiments described above (e.g., FIG. 6, FIG. 7).

[0299] FIGS. 11a and 11b illustrate the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to perform a cell reselection procedure by applying a predetermined frequency-specific reselection priority and to trigger a random access procedure in a reselected cell.

[0300] More specifically, FIGS. 11a and 11b are drawings illustrating a procedure in which a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention performs a cell reselection procedure by applying a predetermined frequency-specific reselection priority when a random access procedure is triggered to perform an RRC connection establishment procedure or an RRC connection resume procedure, and triggers or initiates a random access procedure in the reselected cell to perform an RRC connection establishment procedure or an RRC connection resume procedure.

[0301] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels separate from low-power wake-up signals / channels are provided, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can select or re-select a cell operating at the MR frequency through the terminal's MR and perform a Random Access procedure on the cell. The terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR.For reference, a given cell may be operated simultaneously at MR and LR frequencies, operated only at MR frequencies, or operated only at LR frequencies.

[0302] Referring to FIGS. 11a and 11b, the terminal (1101) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (1105) (1110).

[0303] In step 1115, the base station (1105) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (1101) to retrieve terminal radio access capability information (UE radio access capability information).

[0304] In step 1120, the terminal (1101) may transmit a terminal capability information message (UECapabilityInformation) to the base station (1105). The information included in the message transmitted by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 8, FIG. 9). A message following one embodiment of the present disclosure may include at least one of the following information.

[0305] - Information indicating the ability to perform an RRC connection establishment or RRC connection resume procedure by triggering a random access procedure to perform an RRC connection resume procedure in a currently serving cell operating on MR and LR frequencies (e.g., upon receiving a paging message containing a PagingUE-Identity indicating a terminal), without immediately triggering or initiating the random access procedure, performing a cell reselection procedure by applying frequency-specific cell reselection priorities for certain MR frequencies, and triggering or initiating the random access procedure in the reselected cell.

[0306] Here, the predetermined MR frequencies and the cell reselection priority value for each MR frequency may be broadcast to the terminal through system information broadcast by the serving cell or set as an RRC disconnection message (RRCRelease).

[0307] In step 1125, the terminal (1101) may receive an RRC disconnection message (RRCRelease) from the base station (1105). The information included in the message received by the terminal may follow at least one of the embodiments described above (e.g., FIG. 5, FIG. 9, FIG. 10). The message received by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0308] - An indicator that, when a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), does not immediately trigger or initiate the procedure, but instead instructs to trigger or initiate the random access procedure in the cell re-selected through the cell re-selection procedure.

[0309] Here, the cell reselection procedure may mean performing the procedure by applying the specified MR frequencies and the reselection priority values ​​for each MR frequency, which are broadcast in the system information or set in the RRC disconnection message.

[0310] - When a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receipt of a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), certain MR frequencies and reselection priority values ​​per MR frequency for reselecting the cell to trigger or initiate the random access procedure.

[0311] Here, the predetermined MR frequencies and the re-selection priority values ​​for each MR frequency may follow the aforementioned embodiment (e.g., FIG. 5).

[0312] - New timer value

[0313] The timer value may represent a value that determines how much the indicator and / or the predetermined MR frequencies and the reselection priority value for each frequency are applied. That is, when a new timer value is set, the terminal drives the timer with that value, and while the timer is running, it can perform the operation described above by applying the indicator and / or the predetermined MR frequencies and the reselection priority value for each frequency. For reference, the timer value may be set together with the indicator and / or the predetermined MR frequencies and the reselection priority value for each frequency, or only the timer value may be set. Even if only the timer value is set, the operation of the terminal may be the same.

[0314] In step 1130, the terminal (1101) can apply the received RRC disconnection message and transition to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE).

[0315] In step 1135, a terminal (1101) in RRC idle mode or RRC disabled mode may perform a cell selection procedure to camp-on to an NR suitable cell (1105). This may follow the aforementioned embodiment (e.g., FIG. 5). The cell according to the present disclosure may be operated at MR and LR frequencies. That is, the cell may also transmit low-power wake-up signals (hereinafter LP-WUS) and transmit and receive NR signals separate from the low-power wake-ups.

[0316] In step 1140, the terminal (1101) may obtain system information containing cell reselection information (e.g., SIB2, SIB3, SIB4, SIB5, new SIB, etc.) from the serving cell (1105) to perform a cell reselection evaluation procedure. This may follow at least one of the aforementioned embodiments (e.g., FIG. 5, FIG. 9, FIG. 10). System information according to one embodiment of the present disclosure may, when a random access procedure is triggered for a terminal (1101) to establish or resume an RRC connection in a current serving cell (1105) (e.g., when a paging terminal identifier (PagingUE-Identity) indicating the terminal is received as a paging message), perform cell reselection by applying a reselection priority value per MR frequency to specific MR frequencies, and then broadcast information on specific MR frequencies and a reselection priority value per MR frequency that is necessary to perform an RRC connection establishment procedure or an RRC connection resumption procedure by triggering or initiating a random access procedure in the reselected cell.

[0317] The reselection priority value by MR frequency may refer to the cell reselection priority setting information of the aforementioned embodiment (e.g., FIG. 5). The information on specific MR frequencies and the reselection priority value by MR frequency may be broadcast through new system information, or a separate reselection priority value may be included in one of the MR frequencies among the MR frequencies included in the system information containing existing cell reselection information. For convenience of explanation, the specific MR frequencies according to one embodiment of the present disclosure may refer to NR frequency band 2 and NR frequency band 3, the surrounding cells for NR frequency band 2 may refer to NR cell y (1106) and NR cell z (1107), and the surrounding cells for NR frequency band 3 may refer to NR cell a (1108) and NR cell b (1109). If a specific MR frequency is set in the RRC disconnection message, the terminal may apply the specific MR frequency set in the RRC disconnection message without applying the specific MR frequency included in the system information. However, if the specific MR frequency broadcast in the system information and the specific MR frequency set in the RRC disconnection message are the same, the terminal may apply the cell list for the specific MR frequency in the system information when it is broadcast.

[0318] In step 1145, the terminal (1101) can turn off the terminal's MR (1102) and use the LR (1103) to monitor the low-power wake-up signal (hereinafter LP-WUS) transmitted by the cell (1105) when a predetermined condition is met. This may follow the previously described embodiment (e.g., FIG. 9).

[0319] In step 1150, the LR (1103) of the terminal (1101) can receive the LP-WUS transmitted by the cell (1105). This may follow the previously described embodiment (e.g., FIG. 9).

[0320] In step 1155, the terminal (1101) can monitor the Paging Early Indication occasion (PEI-O) using the terminal's MR (1102). Accordingly, the terminal can receive (1160) the PEI transmitted by the cell (1105) using the terminal's MR. Steps 1155 and 1160 may follow the aforementioned embodiment (e.g., FIG. 9).

[0321] In step 1165, the terminal (1101) can monitor the Paging Occasion (PO) using the terminal's MR (1102). Accordingly, the terminal can receive (1170) a Short Message transmitted by the cell (1105) using the terminal's MR. Steps 1165 and 1170 may follow the aforementioned embodiment (e.g., FIG. 9).

[0322] In step 1175, the terminal (1101) can monitor the paging channel using the terminal's MR (1102). Accordingly, the terminal can receive (1180) a Paging message transmitted by the cell (1105) through the terminal's MR. Steps 1175 and 1180 may follow the aforementioned embodiment (e.g., FIG. 9).

[0323] In step 1181, the terminal (1101) may determine that it needs to perform a random access procedure to switch to an RRC connection mode. For example, the terminal may determine that it needs to perform a random access procedure if the paging message received in step 1180 contains a paging terminal identifier (PagingUE-Identity) that identifies the terminal, or if there is a reason to perform an RRC connection establishment procedure or an RRC connection resumption procedure with the base station (e.g., when mobile originated signaling needs to be sent). Note that the terminal may not immediately initiate the random access procedure or may not trigger the random access procedure even if the random access procedure is triggered in step 1181.

[0324] In step 1185, the terminal (1101) may perform a cell reselection procedure through the terminal's MR (1102) by applying a reselection priority value for each frequency to the NR frequency band 2 and NR frequency band 3 received in step 1125 or step 1140. This may follow the previously described embodiment (e.g., FIG. 9). A terminal following one embodiment of the present disclosure may perform a cell reselection procedure by applying the above-described content in step 1140 when a cell list (1106, 1107) for NR frequency band 2 and / or a cell list (1108, 1109) for NR frequency band 3 is broadcast.

[0325] In step 1190, the terminal (1101) can re-select an NR cell (1103) operating in NR frequency band 2 through step 1185.

[0326] In step 1195, the terminal (1101) may perform a random access procedure, an RRC connection establishment procedure, or an RRC connection resumption procedure with the re-selected NR cell (1103). This may follow the embodiments described above (e.g., FIG. 6, FIG. 7).

[0327] FIG. 12 illustrates the flow of signals for a terminal to perform a random access procedure when a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention fails to re-select a cell.

[0328] More specifically, FIG. 12 is a diagram illustrating the operation of a terminal that performs a random access procedure in a next-generation mobile communication system according to an embodiment of the present invention, in which a random access procedure is triggered to perform an RRC connection establishment procedure or an RRC connection resume procedure, but the random access procedure is not immediately initiated, and a cell reselection procedure is performed according to a predetermined condition but the cell is not reselected.

[0329] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels are provided separately from low-power wake-up signals / channels, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can select or re-select a cell operating at the MR frequency through the terminal's MR and perform a Random Access procedure on the cell. The terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR.For reference, a given cell may be operated simultaneously at MR and LR frequencies, operated only at MR frequencies, or operated only at LR frequencies.

[0330] Referring to FIG. 12, the terminal (1201) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (1205) (1210).

[0331] In step 1215, the base station (1205) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (1201) to retrieve terminal radio access capability information (UE radio access capability information).

[0332] In step 1220, the terminal (1201) may transmit a terminal capability information message (UECapabilityInformation) to the base station (1205). The information included in the message transmitted by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 8, FIG. 9, FIG. 10, FIG. 11). The message transmitted by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0333] - Information indicating the ability to perform RRC connection establishment or RRC connection resumption by triggering or initiating a random access procedure with a newly selected cell or a currently suitable serving cell (e.g., a currently camping cell) through a cell selection process, without immediately triggering or initiating the random access procedure (e.g., support of fallback to trigger / initiate random access procedure), in the case where a cell reselection procedure was performed according to at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11) but a cell could not be reselected; and in the case where a cell reselection procedure was performed but a cell could not be reselected.

[0334] Here, the case where a cell cannot be re-selected may mean that the terminal transitions to the Any Cell Selection state or that the currently suitable serving cell is still the best cell for a predetermined period of time (e.g., the cell re-selection validity period set by the base station, or during a specific x-time Paging Occasion period, or during a specific y-time DRX cycle).

[0335] In step 1225, the terminal (1201) may receive an RRC disconnection message (RRCRelease) from the base station (1205). The information included in the message received by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 5, FIG. 9, FIG. 10, FIG. 11). The message received by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0336] - An indicator that, when a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), does not immediately trigger or initiate it, but instead, if a cell reselection procedure was performed but a cell could not be reselected, instructs to trigger or initiate the random access procedure with the newly selected cell or the currently suitable serving cell through the cell selection process.

[0337] Here, in the case where the terminal determines that it cannot re-select a cell, a value indicating a specific time may be set in the message received by the terminal. For example, the value indicating a specific time may mean a time value indicating the period for performing re-selection or a value indicating how many times a specific time cycle (e.g., DRX cycle, PO occasion) occurs. For reference, if a value indicating a specific time is set without the above indicator, the terminal may trigger or initiate a random access procedure with a newly selected cell or a currently suitable cell (e.g., a cell currently camping) through the cell selection process when it cannot re-select a cell.

[0338] In step 1230, the terminal (1201) can apply the received RRC disconnection message and transition to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE).

[0339] In step 1235, a terminal (1201) in RRC idle mode or RRC disabled mode may perform a cell selection procedure to camp-on to an NR suitable cell (1205). This may follow the aforementioned embodiment (e.g., FIG. 5). The cell according to the present disclosure may be operated at MR and LR frequencies. That is, the cell may also transmit low-power wake-up signals (hereinafter LP-WUS) and transmit and receive NR signals separate from the low-power wake-ups.

[0340] In step 1240, the terminal (1201) may obtain system information containing cell reselection information (e.g., SIB2, SIB3, SIB4, SIB5, new SIB, etc.) from the serving cell (1205) to perform a cell reselection evaluation procedure. This may follow at least one of the embodiments described above (e.g., FIG. 5, FIG. 9, FIG. 10, FIG. 11). System information according to one embodiment of the present disclosure may broadcast at least one of the information described above (i.e., an indicator or a predetermined time value) in step 1225. For reference, information in the RRC disconnection message may take precedence over information included in the system information.

[0341] In step 1245, the terminal (1201) can turn off the terminal's MR (1202) and use the LR (1203) to monitor the low-power wake-up signal (hereinafter LP-WUS) transmitted by the cell (1205) when a predetermined condition is met. This may follow the previously described embodiment (e.g., FIG. 9).

[0342] In step 1250, the LR (1203) of the terminal (1201) can receive the LP-WUS transmitted by the cell (1205). This may follow the previously described embodiment (e.g., FIG. 9).

[0343] In step 1255, the terminal (1201) can monitor the Paging Early Indication occasion (PEI-O) using the terminal's MR (1202). Accordingly, the terminal can receive (1260) the PEI transmitted by the cell (1205) using the terminal's MR. Steps 1255 and 1260 may follow the previously described embodiment (e.g., FIG. 9). The PEI according to one embodiment of the present disclosure may include at least one of the information described above in step 1225 (i.e., an indicator or a predetermined time value).

[0344] In step 1265, the terminal (1201) can monitor the Paging Occasion (PO) using the terminal's MR (1202). Accordingly, the terminal can receive (1270) a Short Message transmitted by the cell (1205) using the terminal's MR. Steps 1265 and 1270 may follow the previously described embodiment (e.g., FIG. 9). A Short Message following one embodiment of the present disclosure may include at least one of the information described above in step 1225 (i.e., an indicator or a predetermined time value).

[0345] In step 1275, the terminal (1201) can monitor the paging channel using the terminal's MR (1202). Accordingly, the terminal can receive (1280) a Paging message transmitted by the cell (1205) through the terminal's MR. Steps 1275 and 1280 may follow the previously described embodiment (e.g., FIG. 9). A Paging message following one embodiment of the present disclosure may include at least one of the information described above in step 1225 (i.e., an indicator or a predetermined time value).

[0346] In step 1281, the terminal (1201) may determine that it needs to perform a random access procedure to switch to an RRC connection mode. This may follow at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11).

[0347] In step 1285, the terminal (1201) may perform a cell reselection procedure through the terminal's MR (1202) according to at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11). This may follow the aforementioned embodiment (e.g., FIG. 9).

[0348] At step 1290, the terminal (1201) may not be able to re-select a cell. For example, the terminal may transition to an Any Cell Selection state where it is not camping in any cell, or it may not re-select another cell because there is no cell better than the current serving cell (1206) for a predetermined time. The predetermined time may be determined by the terminal implementation or may mean a time provided to the terminal according to at least one of steps 1225, 1240, 1250, 1260, 1270, or 1280.

[0349] In step 1295, the terminal (1201) may perform a cell selection process or, if the most recent serving cell (1206) is still suitable, perform a random access procedure with the NR cell (1203), an RRC connection establishment procedure, or an RRC connection resumption procedure. This may follow the embodiments described above (e.g., FIG. 6, FIG. 7). For convenience of explanation, the cell selected by performing the cell selection process may be NR cell x (1206), or the most recent serving cell (1206) may still be suitable.

[0350] FIG. 13 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to continue performing a cell reselection procedure according to a predetermined condition after initiating a random access procedure.

[0351] More specifically, FIG. 13 is a diagram illustrating the operation in which a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention triggers a random access procedure to perform an RRC connection establishment procedure or an RRC connection resume procedure and immediately initiates it, but continues to perform a cell reselection procedure according to a predetermined condition.

[0352] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels separate from low-power wake-up signals / channels are provided, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can select or re-select a cell operating at the MR frequency through the terminal's MR and perform a Random Access procedure on the cell. The terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR.For reference, a given cell may be operated simultaneously at MR and LR frequencies, operated only at MR frequencies, or operated only at LR frequencies.

[0353] Referring to FIG. 13, the terminal (1301) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (1305) (1310).

[0354] In step 1315, the base station (1305) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (1301) to retrieve terminal radio access capability information (UE radio access capability information).

[0355] In step 1320, the terminal (1301) may transmit a terminal capability information message (UECapabilityInformation) to the base station (1305). The information included in the message transmitted by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 8, FIG. 9, FIG. 10, FIG. 11, FIG. 12). The message transmitted by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0356] - When a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure in a currently serving cell operating at MR and LR frequencies (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), the random access procedure is initiated immediately, but information on the capability to perform a cell reselection procedure by changing the cell reselection priority(ies) according to at least one of the aforementioned embodiments (e.g., support of continuing to perform cell reselection by applying new reselection priority(ies) after the random access procedure is triggered)

[0357] In step 1325, the terminal (1301) may receive an RRC disconnection message (RRCRelease) from the base station (1305). The information included in the message received by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 5, FIG. 9, FIG. 10, FIG. 11). The message received by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0358] - An indicator that, when a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating said terminal), immediately initiates the random access procedure but instructs to perform a cell reselection procedure by changing the cell reselection priority according to at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11).

[0359] - When a random access procedure is triggered to perform an RRC connection establishment or RRC connection resumption procedure (e.g., upon receiving a paging message containing a paging terminal identifier (PagingUE-Identity) indicating a terminal), the random access procedure is initiated immediately, but at least one predetermined MR frequency and / or a cell list for a specific predetermined MR frequency is required to change the cell reselection priority according to at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11).

[0360] In step 1330, the terminal (1301) can apply the received RRC disconnection message and transition to RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE).

[0361] In step 1335, a terminal (1301) in RRC idle mode or RRC disabled mode may perform a cell selection procedure to camp-on to an NR suitable cell (1305). This may follow the aforementioned embodiment (e.g., FIG. 5). The cell according to the present disclosure may be operated at MR and LR frequencies. That is, the cell may also transmit low-power wake-up signals (hereinafter LP-WUS) and transmit and receive NR signals separate from the low-power wake-ups.

[0362] In step 1340, the terminal (1301) may obtain system information containing cell reselection information (e.g., SIB2, SIB3, SIB4, SIB5, new SIB, etc.) from the serving cell (1305) to perform a cell reselection evaluation procedure. This may follow at least one of the embodiments described above (e.g., FIG. 5, FIG. 9, FIG. 10, FIG. 11). In the system information according to one embodiment of the present disclosure, the information described above in step 1325 (i.e., an indicator and / or at least one predetermined MR frequency and / or a cell list for a specific predetermined MR frequency) may be broadcast. For reference, information in the RRC disconnection message may take precedence over information included in the system information.

[0363] In step 1345, the terminal (1301) can turn off the terminal's MR (1302) and use the LR (1303) to monitor the low-power wake-up signal (hereinafter LP-WUS) transmitted by the cell (1305) when a predetermined condition is met. This may follow the previously described embodiment (e.g., FIG. 9).

[0364] In step 1350, the LR (1303) of the terminal (1301) can receive the LP-WUS transmitted by the cell (1305). This may follow the previously described embodiment (e.g., FIG. 9).

[0365] In step 1355, the terminal (1301) can monitor the Paging Early Indication occasion (PEI-O) using the terminal's MR (1302). Accordingly, the terminal can receive (1360) the PEI transmitted by the cell (1305) using the terminal's MR. Steps 1355 and 1360 may follow the previously described embodiment (e.g., FIG. 9). The PEI according to one embodiment of the present disclosure may include the indicator described above in step 1325.

[0366] In step 1365, the terminal (1301) can monitor the Paging Occasion (PO) using the terminal's MR (1302). Accordingly, the terminal can receive (1370) a Short Message transmitted by the cell (1305) using the terminal's MR. Steps 1365 and 1370 may follow the previously described embodiment (e.g., FIG. 9). A Short Message following one embodiment of the present disclosure may include the indicator described above in step 1325.

[0367] In step 1375, the terminal (1301) can monitor the paging channel using the terminal's MR (1302). Accordingly, the terminal can receive (1380) a Paging message transmitted by the cell (1305) through the terminal's MR. Steps 1375 and 1380 may follow the previously described embodiment (e.g., FIG. 9). A Paging message following one embodiment of the present disclosure may include the indicator described above in step 1325.

[0368] At step 1381, the terminal (1301) may determine that it must perform a random access procedure to switch to an RRC connection mode. This may follow at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11).

[0369] At step 1383, the terminal (1301) may continue the cell reselection procedure by changing the cell reselection priority (e.g., applying it if an additional cell list is provided) according to at least one of the aforementioned embodiments (e.g., FIG. 9, FIG. 10, FIG. 11). For reference, the terminal may continue the cell reselection procedure by changing the cell reselection priority after step 1350, after step 1360, after step 1370, or after step 1380. This is to allow the terminal to reselect a cell in advance by changing the cell reselection priority in advance, as a random access procedure may be triggered.

[0370] In step 1385, the terminal (1301) may perform a random access procedure, an RRC connection establishment procedure, or an RRC connection resumption procedure with the cell (1305). For reference, step 1385 may be performed as in step 1383 or before step 1383 (i.e., after step 1381).

[0371] In step 1390, the terminal (1301) may re-select the cell (1306) if the following condition is satisfied while performing step 1385.

[0372] - When the terminal re-selects another predetermined cell (1306) while performing a random access procedure with the cell (1305) because the cell re-selection condition is satisfied

[0373] - When the terminal re-selects another predetermined cell (1306) while the cell (1300) is running during the procedure to establish an RRC connection with the cell (1305), the cell re-selection condition is satisfied (i.e., since the terminal stops the running T300 timer when it receives the RRCSetup message, this means before the T300 timer is stopped).

[0374] - While performing the procedure to resume the RRC connection with the cell (1305), if the terminal re-selects another predetermined cell (1306) because the cell re-selection condition is satisfied while the T319 timer is running (i.e., since the terminal stops the running T319 timer when it receives the RRCSetup message or RRCResume message, this means before the T319 timer is stopped)

[0375] In step 1395, the terminal (1301) can perform a random access procedure, an RRC connection establishment procedure, or an RRC connection resumption procedure with the re-selected cell (1306).

[0376] FIG. 14 illustrates the flow of signals for a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention to monitor a downlink signal transmitted by a cell or base station belonging to a different band than the cell or base station that received the low-power wake-up signal.

[0377] More specifically, FIG. 14 is a diagram illustrating the operation of a terminal supporting a low-power wake-up receiver in a next-generation mobile communication system according to an embodiment of the present invention, which monitors a low-power wake-up signal from a cell or base station belonging to a predetermined band in an RRC connection mode (RRC_CONNECTED), and monitors a Physical Downlink Control Channel (PDCCH) transmitted by a cell or base station belonging to a different band than the cell or base station that received the low-power wake-up signal based on the received low-power wake-up signal.

[0378] A terminal according to one embodiment of the present disclosure may perform a predetermined operation by being equipped with a Main Radio (hereinafter MR) and a Low Power Wake-Up Receiver (hereinafter LR). The MR installed in the terminal refers to a transceiver module (Tx / Rx module operating for NR signals / channels apart from signals / channels related to low-power wake-up) that operates for NR signals / channels separate from low-power wake-up signals / channels, and the LR additionally installed in the terminal may refer to a receiver module (Rx module operating for receiving / processing signals / channels related to low-power wake-up) that operates to receive or process signals / channels related to low-power wake-up. Since the power consumed when using the LR is less than that of the MR, the terminal may obtain a power saving effect by turning off the MR and using the LR under predetermined conditions, or by having the LR perform measurements instead of the MR. For convenience of explanation, in one embodiment of the present disclosure, the term MR frequency is used as a concept of a frequency where NR signals / channels are provided separately from low-power wake-up signals / channels, and the term LR frequency is used as a concept of a frequency where signals / channels related to low-power wake-up are provided. For example, a terminal can obtain a power saving effect by receiving signals / channels related to low-power wake-up from a cell operating at the LR frequency through the terminal's LR. Specifically, a terminal in RRC connection mode can monitor and receive a low-power wake-up signal (LP-WUS) transmitted by a cell or base station operating at the LR frequency through the terminal's LR.The LP-WUS may include information for instructing a terminal to monitor a PDCCH at a specific base station, a specific cell, or a specific frequency (e.g., MR frequency). The terminal can monitor a Physical Downlink Control Channel (PDCCH) transmitted by a cell or base station operating at the MR frequency through the terminal's MR. The cell may refer to at least one of a Primary Cell (PCell), a Primary Secondary Cell (PSCell), or a specific Secondary Cell (SCell), and the base station may refer to at least one of a Master Node (MN) or a Secondary Node (SN). For reference, the specific cell or base station may be operated simultaneously at the MR frequency and the LR frequency, may be operated only at the MR frequency, or may be operated only at the LR frequency.

[0379] Referring to FIG. 14, the terminal (1401) may be in an RRC connection mode (RRC_CONNECTED) by establishing an RRC connection with the base station (1405) (1410).

[0380] In step 1415, the base station (1405) may send a terminal capability report request message (UECapabilityEnquiry) to the terminal (1401) to retrieve terminal radio access capability information (UE radio access capability information).

[0381] In step 1420, the terminal (1401) may transmit a terminal capability information message (UECapabilityInformation) to the base station (1405). The information included in the message transmitted by the terminal may follow at least one of the aforementioned embodiments (e.g., FIG. 8, FIG. 9, FIG. 10, FIG. 11, FIG. 12, FIG. 13). The message transmitted by the terminal according to one embodiment of the present disclosure may include at least one of the following information.

[0382] - Terminal capability information for monitoring / receiving LP-WUS via the terminal's LR (1403) from a base station or cell at a specified frequency (e.g., LR frequency, or a frequency where both MR and LR frequencies are supported simultaneously).

[0383] Here, the reason for monitoring / receiving LP-WUS is to monitor PDCCH from other base stations or cells.

[0384] - Terminal capability information for monitoring / receiving PDCCH via the terminal's MR (1402) at a base station or cell located at a specified frequency indicated by the LP-WUS (e.g., an MR frequency, or a frequency where both MR and LR frequencies are supported simultaneously).

[0385] The LP-WUS may contain information regarding which frequency, base station, or cell is instructed to monitor the PDCCH. That is, the frequency / base station / cell monitoring the LP-WUS via the terminal's LR (1403) and the frequency / base station / cell monitoring the PDCCH via the terminal's MR (1402) may be different. For reference, the base station and cell for monitoring the PDCCH via the terminal's MR may be as follows.

[0386] - The above cell may mean at least one of a Primary Cell (PCell), a Primary Secondary Cell (PSCell), and a predetermined Secondary Cell (SCell).

[0387] - The above base station may mean at least one of a Master Node (MN) or a Secondary Node (SN).

[0388] For reference, terminal capability information may refer to a single terminal capability information that combines at least one of the above-described items.

[0389] In step 1425, the terminal (1401) can monitor the LP-WUS transmitted from the base station or cell (1405) through the terminal's LR (1403).

[0390] In step 1430, the terminal (1401) can receive an LP-WUS transmitted by the base station or cell (1405) through the terminal's LR (1403). The LP-WUS may include at least one of the following information.

[0391] - Specific cell information for monitoring PDCCH through the terminal's MR (1402), or an indicator indicating monitoring PDCCH in a specific cell

[0392] Here, a specific cell may refer to at least one of a Primary Cell (PCell), a Primary Secondary Cell (PSCell), and a specified Secondary Cell (SCell). For reference, a specific cell may refer to a cell operating at a specific frequency (e.g., MR frequency).

[0393] Here, information about a specific cell can be pre-configured to the terminal (1401) via an RRC message (e.g., RRCReconfiguration).

[0394] - Specific base station information for monitoring the PDCCH via the terminal's MR (1402), or an indicator instructing to monitor the PDCCH at a specific base station

[0395] Here, a specific base station may mean at least one of MN or SN.

[0396] Here, information about a specific base station can be pre-configured to the terminal (1401) via an RRC message (e.g., RRCReconfiguration).

[0397] - Specific frequency information for monitoring the PDCCH via the terminal's MR (1402), or an indicator indicating monitoring the PDCCH at a specific frequency

[0398] Here, a specific frequency may refer to the MN frequency.

[0399] Here, information regarding a specific MN frequency can be pre-set to the terminal (1401) via an RRC message (e.g., RRCReconfiguration).

[0400] In step 1435, the terminal (1401) can monitor the PDCCH at a specific base station or a specific cell at a specific frequency or at a specific frequency (1406) through the terminal's MR (1402).

[0401] In step 1440, the terminal (1401) can receive a signal transmitted to the PDCCH through step 1435 via the terminal's MR (1402).

[0402] FIG. 15 illustrates the structure of a terminal according to one embodiment of the present invention.

[0403] Referring to the drawing above, the terminal includes an RF (Radio Frequency) processing unit (1510), a baseband processing unit (1520), a storage unit (1530), and a control unit (or controller) (1540).

[0404] The RF processing unit (1510) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1510) up-converts the baseband signal provided by the baseband processing unit (1520) into an RF band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1510) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC (digital to analog converter), an ADC (analog to digital converter), etc. Although only one antenna is shown in the drawing, the terminal may be equipped with multiple antennas. In addition, the RF processing unit (1510) may include multiple RF chains. Furthermore, the RF processing unit (1510) may perform beamforming. For the above beamforming, the RF processing unit (1510) can adjust the phase and magnitude of each of the signals transmitted and received through a plurality of antennas or antenna elements. In addition, the RF processing unit can perform MIMO and can receive multiple layers when performing MIMO operation.

[0405] The baseband processing unit (1520) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (1520) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (1520) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (1510). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (1520) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT (inverse fast Fourier transform) operation and CP (cyclic prefix) insertion. Additionally, upon receiving data, the baseband processing unit (1520) divides the baseband signal provided by the RF processing unit (1510) into OFDM symbol units, restores the signals mapped to subcarriers through a fast Fourier transform (FFT), and then restores the received bit sequence through demodulation and decoding.

[0406] The baseband processing unit (1520) and the RF processing unit (1510) transmit and receive signals as described above. Accordingly, the baseband processing unit (1520) and the RF processing unit (1510) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, or a communication unit. Furthermore, at least one of the baseband processing unit (1520) and the RF processing unit (1510) may include a plurality of communication modules to support a plurality of different wireless access technologies. Additionally, at least one of the baseband processing unit (1520) and the RF processing unit (1510) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include wireless LAN (e.g., IEEE 802.11), cellular network (e.g., LTE), etc. In addition, the above different frequency bands may include super high frequency (SHF) bands (e.g., 2 NRHz, NRHz) and millimeter wave (e.g., 60 GHz) bands.

[0407] The storage unit (1530) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (1530) can store information related to a second connection node that performs wireless communication using a second wireless connection technology. Additionally, the storage unit (1530) provides the stored data upon the request of the control unit (1540).

[0408] The control unit (1540) controls the overall operations of the terminal. For example, the control unit (1540) transmits and receives signals through the baseband processing unit (1520) and the RF processing unit (1510). Additionally, the control unit (1540) writes and reads data to and from the storage unit (1540). To this end, the control unit (1540) may include at least one processor. For example, the control unit (1540) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as applications.

[0409] FIG. 16 illustrates the structure of a base station according to one embodiment of the present invention.

[0410] As illustrated in the drawing above, the base station is configured to include an RF processing unit (1610), a baseband processing unit (1620), a backhaul communication unit (1630), a storage unit (1640), and a control unit (or controller) (1650).

[0411] The RF processing unit (1610) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1610) upconverts the baseband signal provided by the baseband processing unit (1620) into an RF band signal, transmits it through an antenna, and downconverts the RF band signal received through the antenna into a baseband signal. For example, the RF processing unit (1610) may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. Although only one antenna is shown in the drawing, the first connection node may be equipped with multiple antennas. Additionally, the RF processing unit (1610) may include multiple RF chains. Furthermore, the RF processing unit (1610) may perform beamforming. For beamforming, the RF processing unit (1610) may adjust the phase and magnitude of each of the signals transmitted and received through multiple antennas or antenna elements. The above RF processing unit can perform down-to-down MIMO operation by transmitting one or more layers.

[0412] The baseband processing unit (1620) performs a conversion function between a baseband signal and a bit sequence according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (1620) generates complex symbols by encoding and modulating the transmitted bit sequence. Additionally, when receiving data, the baseband processing unit (1620) restores the received bit sequence by demodulating and decoding the baseband signal provided by the RF processing unit (1610). For example, in the case of following the OFDM method, when transmitting data, the baseband processing unit (1620) generates complex symbols by encoding and modulating the transmitted bit sequence, maps the complex symbols to subcarriers, and then constructs OFDM symbols through IFFT operation and CP insertion. Additionally, upon receiving data, the baseband processing unit (1620) divides the baseband signal provided by the RF processing unit (1610) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operations, and then restores the received bit sequence through demodulation and decoding. The baseband processing unit (1620) and the RF processing unit (1610) transmit and receive signals as described above. Accordingly, the baseband processing unit (1620) and the RF processing unit (1610) may be referred to as a transmitting unit, a receiving unit, a transmitting and receiving unit, a communication unit, or a wireless communication unit.

[0413] The backhaul communication unit (1630) provides an interface for communicating with other nodes within the network. That is, the backhaul communication unit (1630) converts a bit sequence transmitted from the main base station to another node, e.g., an auxiliary base station, a core network, etc., into a physical signal, and converts a physical signal received from the other node into a bit sequence.

[0414] The storage unit (1640) stores data such as basic programs, application programs, and configuration information for the operation of the main station. In particular, the storage unit (1640) can store information regarding bearers assigned to connected terminals, measurement results reported from connected terminals, etc. Additionally, the storage unit (1640) can store information that serves as a criterion for determining whether to provide or disconnect multiple connections to the terminals. Furthermore, the storage unit (1640) provides the stored data in response to a request from the control unit (1650).

[0415] The control unit (1650) controls the overall operations of the main station. For example, the control unit (1650) transmits and receives signals through the baseband processing unit (1620) and the RF processing unit (1610) or through the backhaul communication unit (1630). Additionally, the control unit (1650) writes and reads data to and from the storage unit (1640). To this end, the control unit (1650) may include at least one processor.

[0416] Methods according to the claims or embodiments described in the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0417] When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the claims or embodiments described in the specification of this disclosure.

[0418] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage devices, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0419] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0420] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural form, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0421] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated as needed. For example, parts of one embodiment of the present disclosure and parts of another embodiment may be combined to operate a base station and a terminal. For example, parts of the first embodiment and the second embodiment of the present disclosure may be combined to operate a base station and a terminal. In addition, although the above embodiments are presented based on an FDD LTE system, other variations based on the technical concept of the above embodiments may be implemented in other systems such as a TDD LTE system, 5G, or NR system.

[0422] Meanwhile, the order of description in the drawings illustrating the method of the present invention does not necessarily correspond to the order of execution, and the order of execution may be changed or executed in parallel.

[0423] Alternatively, drawings describing the method of the present invention may omit some components and include only some components to the extent that the essence of the present invention is not impaired.

[0424] In addition, the method of the present invention may be executed by combining some or all of the contents included in each embodiment within a scope that does not impair the essence of the invention. The memory may store programs and data necessary for the operation of the base station. In addition, the memory may store control information or data included in signals transmitted and received by the base station. The memory may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. In addition, there may be multiple memories.

[0425] A processor can control a series of processes to enable a base station to operate according to the embodiments of the present disclosure described above. For example, the processor can control each component of the base station to configure two layers of DCIs containing allocation information for a plurality of PDSCHs and to transmit them. There may be multiple processors, and the processors can perform control operations on the components of the base station by executing a program stored in memory.

Claims

1. In a wireless communication system, a method performed by a terminal (user equipment, UE) is, A step of receiving a system information block (SIB) containing information about a frequency of a second band on a first cell of a first band from a base station; A step of receiving a WUS (wake-up signal) from the base station on the first cell of the first band; A step of receiving a paging message based on the WUS from the base station, on the first cell of the first band; A step of performing a cell reselection procedure for the second cell of the second band; and A method comprising the step of performing a random access procedure on the second cell of the second band.

2. The method of claim 1, wherein the WUS or the paging message includes an indicator that instructs to perform the random access procedure after performing the cell reselection procedure.

3. In Paragraph 1, The above SIB further includes a cell list including cells of the second band, and A method comprising a cell list including at least one of a PCI (physical cell identity) or a cell reselection parameter corresponding to the PCI.

4. The method of claim 1, wherein the SIB further comprises frequency information and priority values ​​for one or more bands.

5. In claim 1, the above method is, A step of determining the failure of the cell reselection procedure if a cell is not selected within a specific time interval during the cell reselection procedure; and A method further comprising the step of performing a random access procedure on the first cell of the first band based on the failure of the cell reselection procedure.

6. In claim 1, the above method is, A method further comprising the step of receiving a timer value based on a time interval for performing the cell reselection procedure from the base station.

7. In claim 1, the above method is, The method further includes the step of transmitting terminal capability information to the base station, which instructs the terminal to support a function of performing the random access procedure after performing the cell reselection procedure. The above SIB or the above paging message is received through the MR (main radio) of the terminal, and The above WUS is received through the LR (low-powered wake-up receiver) of the terminal, and The above WUS is a method that cannot be transmitted on the above second cell.

8. In a wireless communication system, a terminal (user equipment, UE) is, At least one transceiver; At least one processor communicatively coupled to the above at least one transceiver; and It includes at least one memory that is communicationally coupled to the above at least one processor and stores instructions, and The above instructions are executed individually or in any combination by the above at least one processor, so that the terminal: Receive a system information block (SIB) containing information about a frequency of the second band on a first cell of the first band from a base station, and Receive a WUS (wake-up signal) from the base station on the first cell of the first band, and Receive a paging message based on the WUS from the base station, on the first cell of the first band, and Perform a cell reselection procedure for the second cell of the second band above, and A terminal that performs a random access procedure on the second cell of the second band.

9. In claim 8, the terminal, wherein the WUS or the paging message includes an indicator that instructs to perform the random access procedure after performing the cell reselection procedure.

10. In Paragraph 8, The above SIB further includes a cell list including cells of the second band, and The above cell list comprises a terminal including a list including at least one of a physical cell identity (PCI) or a cell reselection parameter corresponding to the said PCI.

11. In claim 8, the terminal, wherein the SIB further comprises frequency information and priority values ​​for one or more bands.

12. In claim 8, the above commands are the terminal: If a cell is not selected within a specific time interval during the cell reselection procedure above, the failure of the cell reselection procedure is determined, and A terminal that performs a random access procedure on the first cell of the first band based on the failure of the cell reselection procedure.

13. In claim 8, the above commands are the terminal: A terminal that receives a timer value based on a time interval for performing the cell reselection procedure from the base station.

14. In claim 8, the above commands are the terminal: Transmit terminal capability information to the base station instructing the terminal to support a function that performs the random access procedure after performing the cell reselection procedure, and The above SIB or the above paging message is received through the MR (main radio) of the terminal, and The above WUS is received through the LR (low-powered wake-up receiver) of the terminal, and The above WUS is a terminal that cannot be transmitted on the above second cell.

Images