Method and device for reselecting on-demand SIB1 transmission cell in next generation mobile communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. This method comprises the steps of: receiving, from a serving cell, at least one piece of system information including cell reselection priority configuration information and / or wake up signal (WUS) configuration information; determining a final candidate target cell on the basis of the cell reselection priority configuration information; determining, on the basis of the WUS configuration information, whether the final candidate target cell is a cell that supports an on-demand system information block 1 (SIB1); transmitting a WUS to the final candidate target cell if the determined final candidate target cell is a cell that supports the on-demand SIB1; receiving, as a response to the WUS transmission, the SIB1 from the final candidate target cell; and, on the basis of the SIB1, determining whether to perform cell reselection for the final candidate target cell.

Description

Method and device for reselecting an ON-DEMAND SIB1 transmission cell in a next-generation mobile communication system

[0001] The present invention relates to the operation of a mobile communication system terminal and base station. More specifically, the present invention relates to a method and device for a terminal to reselect a cell in which to transmit on-demand system information block 1 (SIB 1).

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

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

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

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] The present disclosure proposes a method for a terminal to reselect a cell to transmit on-demand system information block 1 (SIB 1).

[0009] The technical problems to be achieved in the embodiments of the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0010] In order to solve these problems, the present disclosure provides a method performed by a terminal in a wireless communication system, the method comprising: receiving, from a serving cell, at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information; determining a final candidate target cell based on the cell reselection priority setting information; determining, based on the WUS setting information, whether the final candidate target cell is a cell that supports System Information Block 1 (SIB1) on-demand; transmitting a WUS to the final candidate target cell if the determined final candidate target cell is a cell that supports SIB1 on-demand; and receiving an SIB1 from the final candidate target cell in response to the WUS transmission; and determining, based on the SIB1, whether to perform cell reselection to the final candidate target cell.

[0011] In order to solve these problems, the present disclosure provides a method performed by a base station in a wireless communication system, comprising: transmitting to a terminal a Master Information Block (MIB) and a System Information Block 1 (SIB1); and transmitting to the terminal at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information, wherein the WUS setting information is used to determine whether a final candidate target cell determined based on the cell reselection priority setting information is a cell that supports System Information Block 1 (SIB1) on-demand, and when the final candidate target cell is a cell that supports SIB1 on-demand, the final candidate target cell transmits SIB1 to the terminal in response to the WUS, and the SIB1 is characterized in that it is used to determine whether to perform cell reselection to the final candidate target cell.

[0012] In order to solve these problems, the present disclosure provides a terminal in a wireless communication system, comprising: a transceiver for transmitting and receiving signals; and a control unit, wherein the control unit receives, from a serving cell, at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information, determines a final candidate target cell based on the cell reselection priority setting information, determines whether the final candidate target cell is a cell that supports System Information Block 1 (SIB1) on-demand based on the WUS setting information, and transmits a WUS to the final candidate target cell if the determined final candidate target cell is a cell that supports SIB1 on-demand, and receives an SIB1 from the final candidate target cell in response to the WUS transmission, and determines, based on the SIB1, whether to perform cell reselection to the final candidate target cell.

[0013] In order to solve these problems, the present disclosure provides a base station supporting a serving cell in a wireless communication system, comprising: a transceiver for transmitting and receiving signals; and a control unit, wherein the control unit transmits a Master Information Block (MIB) and a System Information Block 1 (SIB1) to a terminal, and transmits at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information to the terminal, wherein the WUS setting information is used to determine whether a final candidate target cell determined based on the cell reselection priority setting information is a cell that supports System Information Block 1 (SIB1) on-demand, and when the final candidate target cell is a cell that supports SIB1 on-demand, the final candidate target cell transmits SIB1 to the terminal in response to the WUS, and the SIB1 is characterized in that it is used to determine whether to perform cell reselection to the final candidate target cell.

[0014] According to one embodiment of the present disclosure, a method of reselecting a cell for transmitting SIB1 on-demand can help save energy at a base station.

[0015] The effects that can be obtained from the present disclosure are not limited to the effects mentioned in the various embodiments, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0016] FIG. 1a is a diagram illustrating the structure of a long term evolution (LTE) system according to one embodiment of the present disclosure.

[0017] FIG. 1b is a diagram illustrating a wireless protocol structure in a long term evolution (LTE) system according to an embodiment of the present disclosure.

[0018] FIG. 1c is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0019] FIG. 1d is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0020] FIG. 1e is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or RRC inactive state (RRC_INACTIVE) to reselect a cell for periodically transmitting essential system information in a next-generation mobile communication system according to an embodiment of the present disclosure.

[0021] FIG. 1f is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0022] FIG. 1g is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand in a next-generation mobile communication system according to an embodiment of the present disclosure.

[0023] FIG. 1h is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0024] FIG. 1i is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0025] FIG. 1J is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0026] FIG. 1k is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0027] FIG. 1l is a block diagram illustrating the internal structure of a New Radio (NR) base station according to one embodiment of the present disclosure.

[0028] The operating principles of the present invention will be described in detail below with reference to the attached drawings. In the following description of the present invention, detailed descriptions of known functions or components will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0029] In the following description of the present invention, detailed descriptions of known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present invention. Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

[0030] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided for convenience of explanation. Therefore, the present invention is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0031] Hereinafter, the base station is an entity that performs resource allocation of the terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, downlink (DL) refers to a wireless transmission path of a signal transmitted from a base station to a terminal, and uplink (UL) refers to a wireless transmission path of a signal transmitted from a terminal to a base station. In addition, although the LTE or LTE-A system may be described below as an example, the embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, the 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included in a system to which the embodiments of the present disclosure may be applied, and 5G below may also be a concept that includes existing LTE, LTE-A, and other similar services. Furthermore, the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure. It will be appreciated that each block of the processing flow diagrams and combinations of the flow diagrams can be executed by computer program instructions.

[0032] These computer program instructions may be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, so that the instructions executed by the processor of the computer or other programmable data processing apparatus create means for performing the functions described in the flowchart block(s). These computer program instructions may also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing apparatus to implement functions in a particular manner, so that the instructions stored in the computer-available or computer-readable memory can produce an article of manufacture that includes instruction means for performing the functions described in the flowchart block(s). The computer program instructions may also be installed on a computer or other programmable data processing apparatus, so that a series of operational steps are performed on the computer or other programmable data processing apparatus to create a computer-implemented process, so that the instructions executing on the computer or other programmable data processing apparatus can provide steps for performing the functions described in the flowchart block(s).

[0033] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order depending on the corresponding function. In this case, the term '~unit' used in the present embodiment means software or a hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the '~unit' may perform certain roles. However, the '~unit' is not limited to software or hardware. The '~unit' may be configured to be on an addressable storage medium and may be configured to execute one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to reproduce one or more CPUs within a device or a secure multimedia card. Also, in an embodiment, the '~ unit' may include one or more processors.

[0034] For convenience of explanation, the present invention uses terms and names defined in the 3rd Generation Partnership Project Long Term Evolution (3GPP) LTE standard. However, the present invention is not limited to these terms and names and can be equally applied to systems conforming to other standards. In the present invention, the term "eNB" may be used interchangeably with "gNB" for convenience of explanation. In other words, a base station described as an eNB may also represent a gNB.

[0035] FIG. 1a is a diagram illustrating the structure of a long term evolution (LTE) system according to one embodiment of the present disclosure.

[0036] Referring to FIG. 1a, as illustrated, the wireless access network of the LTE system is composed of next-generation base stations (Evolved Node Bs, hereinafter referred to as ENBs, Node Bs or base stations) (1a-05, 1a-10, 1a-15, 1a-20), an MME (1a-25, Mobility Management Entity) and an S-GW (1a-30, Serving-Gateway). A user equipment (UE or terminal) (1a-35) accesses an external network through the ENBs (1a-05 to 1a-20) and the S-GW (1a-30).

[0037] In Fig. 1a, ENBs (1a-05 to 1a-20) correspond to the existing Node B of the UMTS system. ENBs are connected to UEs (1a-35) via a wireless channel and perform a more complex role than the existing Node B. In the LTE system, all user traffic, including real-time services such as VoIP (Voice over IP) via the Internet Protocol, is serviced through a shared channel. Therefore, a device that collects status information such as the buffer status of UEs, available transmission power status, and channel status and performs scheduling is required, and ENBs (1a-05 to 1a-20) are in charge of this. One ENB typically controls multiple cells. For example, in order to implement a transmission rate of 100 Mbps, the LTE system uses, for example, orthogonal frequency division multiplexing (OFDM) as a wireless access technology in a 20 MHz bandwidth. In addition, it applies Adaptive Modulation & Coding (AMC) method that determines modulation scheme and channel coding rate according to the channel condition of the terminal. S-GW (1a-30) is a device that provides data bearers and creates or removes data bearers according to the control of MME (1a-25). MME is a device that is responsible for mobility management function for terminals as well as various control functions and is connected to multiple base stations.

[0038] FIG. 1b is a diagram illustrating a wireless protocol structure in a long term evolution (LTE) system according to an embodiment of the present disclosure.

[0039] Referring to Figure 1b, the wireless protocol of the LTE system consists of PDCP (Packet Data Convergence Protocol 1b-05, 1b-40), RLC (Radio Link Control 1b-10, 1b-35), and MAC (Medium Access Control 1b-15, 1b-30) in the terminal and ENB, respectively. PDCP (Packet Data Convergence Protocol) (1b-05, 1b-40) is responsible for operations such as IP header compression / decompression. The main functions of PDCP are summarized as follows.

[0040] - Header compression and decompression (ROHC only)

[0041] - User data transfer function

[0042] - In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM

[0043] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0044] - Duplicate detection function (Duplicate detection of lower layer SDUs at PDCP re-establishment procedure for RLC AM)

[0045] - 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)

[0046] - Encryption and decryption functions (Ciphering and deciphering)

[0047] - Timer-based SDU discard in uplink.

[0048] Radio Link Control (RLC) (1b-10, 1b-35) reconfigures PDCP PDUs (Packet Data Units) to an appropriate size and performs ARQ operations, etc. The main functions of RLC are summarized as follows.

[0049] - Data transfer function (Transfer of upper layer PDUs)

[0050] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0051] - Concatenation, segmentation and reassembly of RLC SDUs (only for UM and AM data transfer)

[0052] - Re-segmentation of RLC data PDUs (only for AM data transfer)

[0053] - Reordering of RLC data PDUs (only for UM and AM data transfer)

[0054] - Duplicate detection (only for UM and AM data transfer)

[0055] - Error detection function (Protocol error detection (only for AM data transfer))

[0056] - RLC SDU discard function (RLC SDU discard (only for UM and AM data transfer))

[0057] - RLC re-establishment function

[0058] MAC (1b-15, 1b-30) connects to multiple RLC layer devices configured in a single terminal, and multiplexes RLC PDUs into MAC PDUs and demultiplexes RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

[0059] - Mapping function (Mapping between logical channels and transport channels)

[0060] - 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)

[0061] - Scheduling information reporting function

[0062] - HARQ function (Error correction through HARQ)

[0063] - Priority handling between logical channels of one UE

[0064] - Priority handling between UEs by means of dynamic scheduling

[0065] - MBMS service identification function

[0066] - Transport format selection function

[0067] - Padding function

[0068] The physical layer (1b-20, 1b-25) performs the operation of channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it over a wireless channel, or demodulating and channel decoding OFDM symbols received over a wireless channel and transmitting them to the upper layer.

[0069] FIG. 1c is a diagram illustrating the structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0070] Referring to FIG. 1c, as illustrated, a wireless access network of a next-generation mobile communication system (hereinafter referred to as NR or 2g) is composed of a next-generation base station (New Radio Node B, hereinafter referred to as NR gNB or NR base station) (1c-10) and an NR CN (1c-05, New Radio Core Network). A user terminal (New Radio User Equipment, hereinafter referred to as NR UE or terminal) (1c-15) accesses an external network through the NR gNB (1c-10) and the NR CN (1c-05).

[0071] In Fig. 1c, the NR gNB (1c-10) corresponds to the eNB (Evolved Node B) of the existing LTE system. The NR gNB is connected to the NR UE (1c-15) via a wireless channel and can provide a service that is superior to the existing Node B. In the next-generation mobile communication system, all user traffic is serviced through a shared channel, so a device that collects status information such as the buffer status of UEs, available transmission power status, and channel status and performs scheduling is required, and the NR NB (1c-10) is in charge of this. One NR gNB typically controls multiple cells. In order to implement ultra-high-speed data transmission compared to the current LTE, it can have a bandwidth higher than the existing maximum, and beamforming technology can be additionally grafted using the orthogonal frequency division multiplexing (OFDM) method as a wireless access technology. In addition, it applies the Adaptive Modulation & Coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel status of the terminal. NR CN (1c-05) performs functions such as mobility support, bearer setup, and QoS setup. NR CN is a device that handles various control functions as well as mobility management functions for terminals and is connected to multiple base stations. In addition, the next-generation mobile communication system can also be linked with the existing LTE system, and NR CN is connected to MME (1c-25) through a network interface. MME is connected to the existing base station, eNB (1c-30).

[0072] FIG. 1d is a diagram illustrating a wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0073] Referring to FIG. 1d, the wireless protocol of the next-generation mobile communication system is composed of NR SDAP (NR service data adaptation protocol, 1d-01, 1d-45), NR PDCP (NR packet data convergence protocol, 1d-05, 1d-40), NR RLC (NR radio link control, 1d-10, 1d-35), and NR MAC (NR medium access control, 1d-15, 1d-30) in the terminal and the New Radio (NR) base station, respectively.

[0074] Key features of NR SDAP (1d-01, 1d-45) may include some of the following:

[0075] - Transfer of user plane data

[0076] - Mapping function between QoS flow and data bearer for both DL and UL

[0077] - QoS flow ID marking function for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0078] - Ability to map relective QoS flow to data bearer for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0079] For the above SDAP layer device, the terminal can be configured by RRC message for each PDCP layer device, each bearer, or each logical channel, whether to use the header of the SDAP layer device or whether to use the function of the SDAP layer device, and when the SDAP header is configured, the terminal can be instructed to update or reset the mapping information for the QoS flow and data bearer of the uplink and downlink with the NAS QoS reflection configuration 1-bit indicator (NAS reflective QoS) and the AS QoS reflection configuration 1-bit indicator (AS reflective QoS) of the SDAP header. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. to support a smooth service.

[0080] The main functions of NR PDCP (1d-05, 1d-40) may include some of the following functions:

[0081] Header compression and decompression (ROHC only)

[0082] - User data transfer function

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

[0084] - Out-of-sequence delivery of upper layer PDUs

[0085] - PDCP PDU reordering for reception

[0086] - Duplicate detection of lower layer SDUs

[0087] - Retransmission function (Retransmission of PDCP SDUs)

[0088] - Encryption and decryption functions (Ciphering and deciphering)

[0089] - Timer-based SDU discard in uplink.

[0090] The reordering function of the NR PDCP device above refers to a function of reordering PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order, or may include a function of transmitting data directly without considering the order, may include a function of recording lost PDCP PDUs by reordering the order, may include a function of reporting the status of lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of lost PDCP PDUs.

[0091] The main features of NR RLC(1d-10, 1d-35) may include some of the following:

[0092] - Data transfer function (Transfer of upper layer PDUs)

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

[0094] - Out-of-sequence delivery of upper layer PDUs

[0095] - ARQ function (Error Correction through ARQ)

[0096] - Concatenation, segmentation and reassembly of RLC SDUs

[0097] - Re-segmentation of RLC data PDUs

[0098] - Reordering of RLC data PDUs

[0099] - Duplicate detection function

[0100] - Protocol error detection

[0101] - RLC SDU discard function

[0102] - RLC re-establishment function

[0103] The in-sequence delivery function of the NR RLC device above refers to the function of sequentially transmitting RLC SDUs received from a lower layer to an upper layer, and may include a function of reassembling and transmitting RLC SDUs when an RLC SDU is originally received divided into multiple RLC SDUs, may include a function of reordering received RLC PDUs based on RLC SN (sequence number) or PDCP SN (sequence number), may include a function of recording lost RLC PDUs by reordering the sequence, may include a function of reporting the status of lost RLC PDUs to the transmitting side, may include a function of requesting retransmission of lost RLC PDUs, may include a function of sequentially transmitting only RLC SDUs up to the lost RLC SDU to an upper layer when there is a lost RLC SDU, or may include a function of sequentially transmitting all RLC SDUs received before the timer starts when a predetermined timer expires even when there is a lost RLC SDU. Or, even if there are lost RLC SDUs, if a predetermined timer has expired, it may include a function to sequentially deliver all RLC SDUs received up to the upper layer. In addition, the RLC PDUs may be processed in the order they are received (in the order of arrival, regardless of the order of the sequence number) and delivered to the PDCP device out of sequence (out-of-sequence delivery). In the case of segments, the segments stored in the buffer or to be received later may be received, reconstructed into a single complete RLC PDU, processed, and then delivered to the PDCP device.The above NR RLC layer may not include a concatenation function, and the above function may be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

[0104] The out-of-sequence delivery function of the NR RLC device above refers to the function of directly delivering RLC SDUs received from a lower layer to an upper layer regardless of the order, and may include a function of reassembling and delivering RLC SDUs when an original RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of received RLC PDUs and arranging the order to record lost RLC PDUs.

[0105] NR MAC (1d-15, 1d-30) can be connected to multiple NR RLC layer devices configured in one terminal, and the main functions of NR MAC can include some of the following functions.

[0106] - Mapping function (Mapping between logical channels and transport channels)

[0107] - Multiplexing / demultiplexing of MAC SDUs

[0108] - Scheduling information reporting function

[0109] - HARQ function (Error correction through HARQ)

[0110] - Priority handling between logical channels of one UE

[0111] - Priority handling between UEs by means of dynamic scheduling

[0112] - MBMS service identification function

[0113] - Transport format selection function

[0114] - Padding function

[0115] The NR PHY layer (1d-20, 1d-25) can perform operations such as channel coding and modulating upper layer data, converting it into OFDM symbols and transmitting it through a wireless channel, or demodulating and channel decoding OFDM symbols received through a wireless channel and transmitting them to a higher layer.

[0116] FIG. 1e is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for periodically transmitting essential system information according to an embodiment of the present disclosure.

[0117] In one embodiment of the present disclosure, a cell is characterized by periodically transmitting essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0118] The cell reselection evaluation procedure may refer to a procedure for determining whether to maintain the current serving cell or reselect a cell to a neighbor cell when the service quality of the serving cell on which the terminal is currently camped becomes lower than that of a neighbor cell due to a predetermined reason or movement, when the terminal is in an RRC (radio resource control) idle mode (RRC_IDLE) or RRC inactive state (RRC_INACTIVE).

[0119] In the case of a handover, whether or not a handover operation is performed is determined by the network (AMF or source gNB). Meanwhile, in the case of cell reselection, a terminal in RRC idle mode or RRC inactive state can determine whether or not to perform cell reselection on its own based on cell measurement values. The cell to be reselected by the terminal may refer to a cell using the same NR frequency (NR intra-frequency or serving NR frequency) as the serving cell on which it is currently camping, a cell using a different NR frequency (NR inter-frequency) from the serving cell, or a cell on a frequency (inter-RAT frequency) using a different radio access technology (RAT).

[0120] Referring to FIG. 1e, in step 1e-03, the terminal (1e-01) may establish an RRC connection with an NR cell (1e-02) and be in RRC connected mode (RRC_CONNECTED). (RRC_CONNECTED)

[0121] In step 1e-04, the NR cell (1e-02) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1e-01) in RRC connection mode. (RRCRelease)

[0122] In step 1e-05, if the message includes suspend configuration information (suspendConfig), the terminal may transition to RRC inactive mode (RRC_INACTIVE). If the message does not include suspend configuration information, the terminal may transition to RRC idle mode (RRC_IDLE). (RRC_IDLE or RRC_INACTIVE)

[0123] The above message may include cellReselectionPriorities for the terminal to perform cell reselection. cellReselectionPriorities may store (or include) at least one of freqPriorityListEUTRA, freqPriorityListNR, and t320. If the t320 value is included, the terminal may start the T320 timer with the corresponding value. More specifically, the configuration information included in the RRCRelease message may be as shown in [Table 1] below.

[0124] [Table 1]

[0125]

[0126]

[0127]

[0128] In step 1e-13, a terminal (1e-01) in RRC idle mode or RRC deactivation state can obtain essential system information from the NR cell (1e-02). In the present disclosure, essential system information may refer to a Master Information Block (MIB) and System Information Block 1 (SIB1).

[0129] In step 1e-15, a terminal (1e-01) in RRC idle mode or RRC deactivation can perform a cell selection procedure based on the essential system information acquired in step 1e-13. (Camp on a NR suitable cell by performing cell reselection)

[0130] That is, the terminal can find an NR suitable cell belonging to the selected PLMN (Public Land Mobile Network) or SNPN (Standalone Non-Public Network) and camp on the cell. The cell on which the terminal camps on can be called a serving cell. In the present disclosure, a suitable cell can be defined if the conditions in [Table 2] below are satisfied based on the 3GPP standard document "38.304: User Equipment (UE) procedures in Idle mode and RRC Inactive state."

[0131] [Table 2]

[0132]

[0133] For reference, the terminal (1e-01) can be judged to fulfill the cell selection criteria if the following mathematical expression 1 is satisfied.

[0134] [Mathematical Formula 1]

[0135]

[0136]

[0137] At step 1e-20, a terminal (1e-01) in RRC idle mode or RRC deactivation state can obtain system information containing cell reselection information from a serving cell (1e-02) to perform a cell reselection evaluation procedure. The system information may include SIB2, SIB3, SIB4, and SIB5.

[0138] SIB2 may include information and / or parameters commonly applied to the RRC terminal when reselecting NR intra-frequency, NR inter-frequency, and inter-RAT frequency cells, and NR intra-frequency cell reselection information excluding information related to NR intra-frequency neighboring cells. For example, SIB2 may include information on setting a single cell reselection priority for a serving NR frequency (a frequency to which the currently camped-on cell belongs). The cell reselection priority setting information may mean cellReselectionPriority and cellReselectionSubPriority. Specifically, cellReselectionPriority may store an integer value, and cellReselectionSubPriority may store a decimal value. For example, the cellReselectionPriority value may include an integer value from 0 to 7, and the cellReselectionSubPriority may include a decimal value from 0.2, 0.4, 0.6, 0.8.

[0139] If both cellReselectionPriority and cellReselectionSubPriority are signaled, the terminal can derive the cell reselection priority value by adding the two values. Note that a higher cell reselection priority value indicates a higher priority. More specifically, the cell reselection configuration information broadcast in SIB2 may be as shown in [Table 3] below.

[0140] [Table 3]

[0141]

[0142]

[0143] SIB3 may include neighboring cell information and / or parameters for a UE in RRC idle mode or RRC inactive state to reselect an NR intra-frequency cell. For example, SIB3 may broadcast an NR intra-frequency cell list (intraFreqNeighCellList) for reselecting an NR intra-frequency cell, a cell list for which NR intra-frequency cell reselection is allowed (intraFreqAllowedCellList), and a cell list for which NR intra-frequency cell reselection is not allowed (intraFreqExcludedCellList). More specifically, SIB3 may broadcast the information in [Table 4] below.

[0144] [Table 4]

[0145]

[0146] SIB4 may include information and / or parameters for a UE in RRC idle mode or RRC inactive 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 means the above-described contents (e.g., cellReselectionPriority and / or cellReselectionSubPriority mapped to each NR inter-frequency), but has the characteristic that one cell reselection priority setting information for each inter-frequency is optionally broadcast. Specifically, the information of [Table 5] below may be broadcast in SIB4.

[0147] [Table 5]

[0148]

[0149]

[0150] SIB5 may include information and / or parameters for a UE in RRC idle mode or RRC inactive 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 above-described contents (e.g., cellReselectionPriority and / or cellReselectionSubPriority mapped to each EUTRA frequency), but has the characteristic that one cell reselection priority setting information for each EUTRA frequency is optionally broadcast. Specifically, the information in [Table 6] below may be broadcast in SIB5.

[0151] [Table 6]

[0152]

[0153] In the present disclosure, it is proposed that a list of cells transmitting SIB1 on-demand by frequency is additionally signaled in the above system information. More specifically, a list of cells by frequency may be broadcast in the above system information, which may refer to a list of cells transmitting SIB1 on-demand. For example, SIB3 may include a list of cells transmitting SIB1 on-demand on a frequency to which the current serving cell belongs. SIB4 may include a list of cells transmitting SIB1 on-demand by adjacent NR frequency. Of course, the above-described content may also be signaled through new system information. The terminal (1e-01) that receives the above cell list may exclude the corresponding cells as cell reselection candidates in the cell reselection evaluation procedure described above.

[0154] A terminal in RRC idle mode or RRC inactive state can perform a cell reselection evaluation process. The cell reselection evaluation process can refer to a series of processes for determining reselection priorities, performing frequency measurements by applying measurement rules for cell reselection, and evaluating cell reselection criteria to reselect a cell.

[0155] At step 1e-25, a terminal (1e-01) in RRC idle mode or RRC disabled state can determine a reselection priority based on the RRC release message received at step 1e-04 or the system information received at step 1e-20. (Handle reselection pririties)

[0156] If the RRC connection release message received in step 1e-04 includes cellReselectionPriorities and there is no t320 timer value in cellReselectionPriorities or the t320 timer value is set and the T320 timer is running, the terminal (1e-01) can determine the reselection priority according to the RRC connection release message. That is, if the celllReselectionPriorities included in the RRC connection release message can be applied, the terminal (1e-01) can determine the reselection priority according to the RRC connection release message.

[0157] If the RRC connection release message does not include cellReselectionPriorities or if cellReselectionPriorities is released, the terminal (1e-01) can determine the reselection priority based on the system information received in step 1e-20.

[0158] According to an embodiment of the present disclosure, the terminal (1e-01) can determine, based on the cell reselection priority value mapped to the NR frequency to which the serving cell currently camped 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, a cell reselection priority higher than the NR frequency to which the serving cell belongs, or a cell reselection priority lower than the NR frequency to which the serving cell belongs. For example, in the system information acquired in step 1e-20, the cell reselection priority value mapped to the NR frequency to which the serving cell currently camped on belongs may be 3, the cell reselection priority value of inter NR frequency 1 may be 2, the cell reselection priority value of inter NR frequency 2 may be 3, the cell reselection priority value of inter NR frequency 3 may be 4, and the cell reselection priority value of EUTRA frequency 1 may be 2. In this case, the terminal may determine inter NR frequency 1 and EUTRA frequency 1 to have lower reselection priorities, determine the cell reselection priorities of inter NR frequency 2 to be equal reselection priorities, and determine the cell reselection priorities of inter NR frequency 3 to be higher reselection priorities.

[0159] At step 1e-30, a terminal (1e-01) in RRC idle mode or RRC inactive state can perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection)

[0160] At this time, the terminal can perform frequency measurement using the following measurement rule according to the cell reselection priority determined at step 1e-25 to minimize battery consumption.

[0161] - The terminal may not perform NR intra-frequency measurement if the following condition 1 is satisfied. Otherwise (e.g., if the following condition 1 is not satisfied), the terminal performs NR intra-frequency measurement.

[0162] ■ Condition 1: The reception level (Srxlev) of the serving cell is greater than the SIntraSearchP threshold and the reception quality (Squal) of the serving cell is greater than the SIntraSearchQ threshold (Serving cell fulfils Srxlev > SIntraSearchP and Squal > SIntraSearchQ).

[0163] - The terminal can perform measurements according to the 3GPP TS 38.133 standard for an NR inter-frequency or inter-RAT frequency with a higher reselection priority than the NR frequency of the current serving cell.

[0164] - If the terminal satisfies Condition 2 below for an NR inter-frequency that has a reselection priority lower than or equal to the NR frequency of the current serving cell and an inter-RAT frequency that has a reselection priority lower than the NR frequency of the current serving cell, the terminal may not perform measurement. Otherwise (for example, if Condition 2 below is not satisfied), the terminal measures cells in an NR inter-frequency that has a reselection priority lower than or equal to the NR frequency, or measures cells in an inter-RAT frequency that has a reselection priority lower than the NR frequency.

[0165] ■ Condition 2: The reception level (Srxlev) of the serving cell is greater than the SnonIntraSearchP threshold and the reception quality (Squal) of the serving cell is greater than the SnonIntraSearchQ threshold (Serving cell fulfils Srxlev > SnonIntraSearchP and Squal > SnonIntraSearchQ).

[0166] For reference, the aforementioned thresholds (SintraSearchP, SintraSearchQ, SnonIntraSearchP SnonintraSearchQ) can be broadcast in the system information acquired at step 1e-20.

[0167] At step 1e-35, 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 at step 1e-30. (Evaluate cell reselection criteria)

[0168] Cell reselection criteria may apply different criteria depending on the cell reselection priority. If multiple cells that satisfy the cell reselection criteria have different cell reselection priorities, reselecting a frequency / RAT cell with a higher cell reselection priority takes precedence over reselecting a frequency / RAT cell with a lower priority.

[0169] More specifically, the operation of the terminal for the reselection criteria of an inter-frequency / inter-RAT cell with a higher priority than the frequency of the current serving cell is as follows.

[0170] - First movement:

[0171] ■ If SIB2 is broadcast with a threshold for threshServingLowQ and 1 second has passed since the terminal camped on 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 inter-frequency / inter-RAT cell.

[0172] - Second movement:

[0173] ■ If the above terminal cannot perform the first operation, it can perform the second operation.

[0174] ■ If 1 second has passed since the terminal camped on 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 Treselection-RAT-), the terminal can perform reselection to the inter-frequency / inter-RAT cell.

[0175] Here, the terminal performs the first or second operation based on information included in SIB4 broadcast from the serving cell, such as signal quality (Squal), reception level (Srxlev), thresholds (ThrehX, HighQ, ThreshX, HighP), and TreselectionRAT values ​​of the inter-frequency cell, and the terminal can perform the first or second operation based on information included in SIB5 broadcast from the serving cell, such as signal quality (Squal), reception level (Srxlev), thresholds (ThreshX,HighQ, ThreshX, HighP), and TreselectionRAT values ​​of the inter-RAT cell. For example, SIB4 includes a Qqualmin value or a Qrxlevmin value, and based on this, the terminal derives the signal quality (Squal) or reception level (Srxlev) of the inter-frequency cell. 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 of the intra-frequency / inter-frequency cell that has the same priority as the frequency of the current serving cell described below.

[0176] In addition, the operation of the terminal for the reselection criteria of the intra-frequency / inter-frequency cell having the same priority as the frequency of the current serving cell is as follows.

[0177] - Third movement:

[0178] ■ If the signal quality (Squal) and reception level (Srxlev) of an intra-frequency / inter-frequency cell are greater than 0, the cell-specific rank is derived based on the measured value (RSRP) (The UE shall perform ranking of all cells that fulfill the cell selection criterion S). The ranks of the serving cell and neighboring cells are each calculated using the following mathematical expression 2.

[0179] [Equation 2]

[0180] R s = Q meas,s + Q hyst - Qoffset temp

[0181] R n = Q meas,n - Qoffset - Qoffset temp

[0182] ● Here, Qmeas,s is the RSRP measurement value of the serving cell, Qmeas,n is the RSRP measurement value of the neighboring cells, Qhyst is the hysteresis value of the serving cell, and Qoffset is the offset between the serving cell and the neighboring cells. The Qhyst value is included in SIB2, and the value is commonly used for intra-frequency / inter-frequency cell reselection. In case of intra-frequency cell reselection, Qoffset is signaled per cell, applied only to the indicated cell, and included in SIB3. In case of inter-frequency cell reselection, Qoffset is signaled per cell, applied only to the indicated cell, and included in SIB4. If the Rank of the neighboring cell obtained from the above mathematical expression 2 is greater than the Rank of the serving cell (Rn > Rs), the optimal cell among the neighboring cells is reselected.

[0183] ● Here Qoffset- temp- - may refer to connEstFailOffset included in ConnEstFailureControld broadcast in SIB1 as an offset temporarily applied to the cell, and may be applied in case of RRC connection failure. An RRC connection failure case may include a case where the T300 timer expires.

[0184] Additionally, the terminal's behavior with respect to the reselection criteria of an inter-frequency / inter-RAT cell with a lower priority than the frequency of the current serving cell is as follows.

[0185] - 4th movement:

[0186] ■ If SIB2 is broadcast with a threshold for threshServingLowQ and 1 second has passed since the terminal camped on the current serving cell, if the signal quality (Sqaul) of the current serving cell is lower than the threshold ThreshServing, LowQ (Squal < ThreshServing, LowQ) and the signal quality (Squal) of the inter-frequency / inter-RAT cell is higher than the threshold ThreshX, LowQ- during a specific time interval TreselectionRAT (Squal > ThreshX,LowQ during a time interval TreselectionRAT), the terminal can perform reselection to the inter-frequency / inter-RAT cell.

[0187] - Movement 5:

[0188] ■ If the above terminal cannot perform the 4th operation, it can perform the 5th operation.

[0189] ■ If 1 second has passed since the terminal camped on the current serving cell, and the reception level (Srxlev) of the current serving cell is less than the threshold ThreshServing, LowP (Srxlev < ThreshServing, LowP) and the reception level (Srxlev) of the inter-frequency / inter-RAT cell is greater than the threshold ThreshX, LowQ- during a specific time interval TreselectionRAT (Srxlev > ThreshX,LowP during a time interval TreselectionRAT), the terminal can perform reselection to the inter-frequency / inter-RAT cell.

[0190] Here, the fourth or fifth operation for the inter-frequency cell of the terminal can be performed based on the thresholds (e.g., ThreshServing, LowQ, ThreshServing, LowP) included in SIB2 broadcasted in the serving cell and the signal quality (Squal), reception level (Srxlev), thresholds (ThrehX, LowQ, ThreshX, LowP), and TreselectionRAT of the inter-frequency cell included in SIB4 broadcasted in the serving cell.

[0191] The fourth or fifth operation of the terminal for the inter-RAT cell can be performed based on the thresholds (e.g., ThreshServing, LowQ, ThreshServing, LowP) included in SIB2 broadcasted in the serving cell and the signal quality (Squal), reception level (Srxlev), thresholds (ThreshX,LowQ, ThreshX, LowP), and TreselectionRAT of the inter-RAT cell included in SIB5 broadcasted in the serving cell. For example, SIB4 includes a Qqualmin value or a Qrxlevmin value, 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 of the intra-frequency / inter-frequency cell that has the same priority as the frequency of the current serving cell.

[0192] At step 1e-40, a terminal (1e-01) in RRC idle mode or RRC inactive state receives system information (e.g., MIB or SIB1) broadcasted from a candidate target cell before finally reselecting a candidate target cell, and based on the received system information, determines whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell satisfy a cell selection criterion called S-criterion (Mathematical Formula 1) (Srxlev > 0 AND Squal > 0). (Before reselecting a candidate target cell, the UE reads system information from that cell and performs a final suitability check.)

[0193] The terminal can re-select the candidate target cell if the mathematical expression 1 is satisfied and the candidate target cell is suitable. (If S-criterion is satisfied, re-select the concerned target cell)

[0194] FIG. 1f is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0195] According to one embodiment of the present disclosure, a given cell may periodically transmit essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0196] Additionally, a given cell according to an embodiment of the present disclosure, unlike the above-described embodiment (FIG. 1e), has a feature that transmits MIB periodically but can transmit SIB1 on-demand. This is because network energy can be saved by transmitting SIB1 when there is a terminal request. More specifically, when a terminal needs to acquire SIB1 for a given reason, the terminal can request that SIB1 be broadcast / transmitted to a cell that does not transmit SIB1. The given reason may include a case of selecting and / or reselecting a cell. Accordingly, the cell that received the request can broadcast SIB1. Referring to FIG. 1f, in step 1f-10, the terminal (1f-01) may establish an RRC connection with an NR cell (1f-05) and be in an RRC connected mode (RRC_CONNECTED).

[0197] In step 1f-15, the terminal (1f-01) may transmit a terminal capability information message (UECapabilityInformation) to the NR cell (1f-05). The terminal capability information message may include capability information indicating that the terminal can transmit (or is capable of transmitting) a wake-up signal (hereinafter referred to as WUS), which is a signal for requesting a cell transmitting SIB1 on-demand to transmit SIB1. (Support of wake-up signal transmission for on-demand SIB1 delivery cell)

[0198] In step 1f-20, the NR cell (1f-05) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1f-01) in RRC connection mode. The information included in the message may follow at least the aforementioned embodiments. Additionally, the message may include at least one of the following:

[0199] - An indicator indicating (or indicating) whether the terminal (1f-01) above can transmit WUS.

[0200] - Setting information required when the above terminal (1f-01) transmits WUS

[0201] ■ The above setting information can be set by frequency or by cell per frequency.

[0202] ■ The above configuration information may refer to one or more random access preambles. For example, it may refer to a preamble indicating the first message (Msg1) sent during a random access procedure.

[0203] ■ The above configuration information may refer to one or more random access opportunities (PRACH occasions) for transmitting a preamble. For example, a RACH occasion may refer to an indication of a frequency and / or time at which a preamble will be transmitted during a random access procedure.

[0204] In step 1f-25, the terminal (1f-01) in the RRC connection mode can apply an RRC connection release message and then transition to the RRC idle mode (RRC_IDLE) or the RRC inactive mode (RRC_INACTIVE) as in the embodiment described above.

[0205] More specifically, if the RRC connection release message includes suspend configuration information (suspendConfig), the terminal can transition to RRC inactive mode (RRC_INACTIVE). On the other hand, if the message does not include suspend configuration information, the terminal can transition to RRC idle mode (RRC_IDLE). (RRC_IDLE or RRC_INACTIVE)

[0206] In step 1f-30, a terminal (1f-01) in RRC idle mode or RRC inactive state can acquire essential system information, MIB and SIB1, from an NR cell (1f-05).

[0207] In step 1f-35, the terminal (1f-01) may perform a cell selection procedure based on step 1f-30. This may follow the embodiment described above.

[0208] In step 1f-40, the terminal (1f-01) may obtain system information containing cell reselection information from the serving cell (1f-05) to perform a cell reselection evaluation procedure. For example, the system information may include SIB2, SIB3, SIB4, SIB5, and new SIB. This may follow the embodiment described above.

[0209] Additionally, the serving cell (1f-05) according to an embodiment of the present disclosure can broadcast system information including WUS configuration information. The serving cell (1f-05) can include the WUS configuration information in at least one of system information among SIB2, SIB3, SIB4, and SIB5 and transmit it to the terminal (1f-01). Alternatively, the serving cell (1f-05) can transmit the WUS configuration information to the terminal (1f-01) through new system information (new SIB). More specifically, the WUS configuration information can be included in the system information through one of the following methods: Method 1 or Method 2.

[0210] - Method 1: WUS configuration per frequency

[0211] ■ The serving cell (1f-05) can provide the terminal (1f-01) with WUS configuration information for the serving frequency (NR intra-frequency) through SIB2 or SIB3, and with WUS configuration information for each adjacent NR frequency (NR inter-frequency) through SIB4. Of course, by defining new system information (new SIB), the serving cell (1f-05) can also provide the terminal (1f-01) with WUS configuration information for each frequency through the new system information.

[0212] - Method 2: WUS configuration per cell (or per cell list) per frequency

[0213] ■ The serving cell (1f-05) can provide the terminal (1f-01) with WUS configuration information per cell or per cell list in the serving frequency (NR intra-frequency) through SIB2 or SIB3, and with WUS configuration information per cell per adjacent NR frequency (NR inter-frequency) or per cell list per NR inter-frequency through SIB4. WUS configuration information per cell list may mean that cells composed of one or more cells share WUS configuration information. Of course, by defining new system information (new SIB), the serving cell (1f-05) can also provide the terminal (1f-01) with WUS configuration information per cell (or per cell list) frequency through the new system information.

[0214] For reference, the WUS configuration information may refer to configuration information required to transmit random access parameters and a random access preamble. For example, the WUS configuration information may refer to at least one of a random access preamble index (or index range), information on the number of SSBs per PRACH Occasion, a reference signal received power (RSRP) threshold (rsrp-ThresholdSSB), and PRACH Occasion location information (information on which a preamble, which is a physical signal specifically designed for uplink synchronization, can be transmitted).

[0215] In step 1f-45, the terminal (1f-01) can determine reselection priorities for cell reselection. (Handle reselection priorities) The method for determining reselection priorities can follow the above-described embodiment (Fig. 1e).

[0216] In step 1f-47, a cell (1f-07) transmitting SIB1 in an on-demand manner can transmit a synchronization signal, SSB (Synchronization Signal / PBCH block, hereinafter referred to as SSB).

[0217] In step 1f-50, the terminal (1f-01) can perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection) The method for performing frequency measurement can follow the above-described embodiment (Fig. 1e).

[0218] In step 1f-55, the terminal (1f-01) can determine a candidate target cell that satisfies the cell reselection criteria based on the measurement values ​​performed in step 1f-50. (Evaluate cell reselection critiera) This can follow the embodiment described above (Fig. 1e).

[0219] Accordingly, the terminal according to the present disclosure can determine the final candidate target cell as the NR cell (1f-07). That is, the NR cell (1f-07) can be the best cell or the highest ranked cell for the terminal (1f-01).

[0220] At step 1f-60, the terminal (1f-01) can identify whether a candidate target cell (1f-07) transmits SIB1 on-demand. (Identify whether a candidate target cell transmits SIB1 via on-demand)

[0221] The terminal according to the present disclosure can be identified through at least one of the following methods 1 to 3.

[0222] - Method 1: The terminal (1f-01) can determine that the NR cell (1f-07) transmits SIB1 on-demand through the MIB transmitted by the cell. For example, the terminal can determine that the NR cell transmits SIB1 on-demand through the ssb-SubcarrierOffset or spare value in the MIB.

[0223] - Method 2: Through step 1f-20 or step 1f-40, the terminal can determine that the NR cell (1f-07) transmits SIB1 on-demand. For example, information that the NR cell transmits SIB1 on-demand may be included in an RRC connection release message or system information.

[0224] - Method 3: The terminal (1f-01) can receive a predetermined message containing WUS configuration information from the NR cell (1f-07) and determine that the cell transmits SIB1 on-demand.

[0225] At step 1f-65, the terminal (1f-01) can transmit a wake-up signal (WUS) to receive SIB1 from the NR cell (1f-07).

[0226] The above terminal (1f-01) can transmit WUS based on WUS configuration information received in step 1f-20, step 1f-40, or step 1f-60. For reference, WUS may also mean a preamble.

[0227] In step 1f-70, the NR cell (1f-07) can transmit SIB1, and the terminal (1f-01) can receive the SIB1. For reference, the terminal (1f-01) can receive the MIB transmitted by the NR cell (1f-07) in step 1f-70 or in a previous step. The previous step may include step 1f-55 or step 1f-60.

[0228] At step 1f-75, the terminal (1f-01) can determine whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell (1f-07) satisfy the cell selection criterion (Srxlev > 0 AND Squal > 0) referred to as S-criterion (Mathematical Formula 1) based on the essential system information (e.g., MIB and SIB1) received from the candidate target cell. (The UE performs a final suitability check.)

[0229] [Mathematical Formula 1]

[0230] Srxlev > 0 AND Squal > 0

[0231] where

[0232] Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset ) - P compensation - -Qoffset temp,

[0233] Squal = Q qualmeas - (Q qualmin + Q qualminoffset ) - Qoffset temp.

[0234] The terminal may re-select the concerned target cell if the S-criterion is satisfied and the candidate target cell is suitable. (If S-criterion is satisfied, re-select the concerned target cell.)

[0235] FIG. 1g is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0236] According to one embodiment of the present disclosure, a given cell may periodically transmit essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0237] Additionally, a given cell according to an embodiment of the present disclosure, unlike the above-described embodiment (Fig. 1e), has a feature that transmits MIB periodically, but can transmit SIB1 on-demand. This is because network energy can be saved by transmitting SIB1 when a terminal requests it. More specifically, when a terminal needs to acquire SIB1 for a given reason, the terminal can request that SIB1 be broadcast / transmitted to a cell that does not transmit SIB1. The given reason may include a case of selecting and / or reselecting a cell. Accordingly, the cell that received the request can broadcast SIB1.

[0238] Referring to FIG. 1g, at step 1g-10, the terminal (1g-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with an NR cell (1g-05).

[0239] In step 1g-15, the terminal (1g-01) can transmit a terminal capability information message (UECapabilityInformation) to the NR cell (1g-05).

[0240] The above terminal capability information message may include capability information indicating that the terminal can transmit (or is capable of transmitting) a wake-up signal (hereinafter referred to as WUS), which is a signal for requesting a cell transmitting SIB1 on-demand to transmit SIB1. (Support of wake-up signal transmission for on-demand SIB1 delivery cell)

[0241] In step 1g-20, the NR cell (1g-05) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1g-01) in RRC connection mode.

[0242] The information contained in the above message may follow at least one of the embodiments described above (Fig. 1e, Fig. 1f).

[0243] In step 1g-25, the terminal (1g-01) in the RRC connection mode can apply an RRC connection release message and then transition to the RRC idle mode (RRC_IDLE) or the RRC inactive mode (RRC_INACTIVE) as in the embodiment described above.

[0244] More specifically, if the RRC connection release message includes suspend configuration information (suspendConfig), the terminal can transition to RRC inactive mode (RRC_INACTIVE). On the other hand, if the message does not include suspend configuration information, the terminal can transition to RRC idle mode (RRC_IDLE). (RRC_IDLE or RRC_INACTIVE)

[0245] In step 1g-30, a terminal (1g-01) in RRC idle mode or RRC inactive state can acquire MIB and SIB1, which are essential system information, from an NR cell (1g-05).

[0246] In step 1g-35, the terminal (1g-01) may perform a cell selection procedure based on step 1g-30. This may follow the embodiment described above (Fig. 1e).

[0247] In step 1g-40, the terminal (1g-01) may acquire system information containing cell reselection information from the serving cell (1g-05) to perform a cell reselection evaluation procedure. For example, the system information may include SIB2, SIB3, SIB4, SIB5, and new SIB. This may follow at least one of the embodiments described above (FIG. 1e, FIG. 1f).

[0248] In step 1g-45, the terminal (1g-01) can determine reselection priorities for cell reselection. (Handle reselection priorities) The method for determining reselection priorities can follow the above-described embodiment (Fig. 1e).

[0249] In step 1g-47, a cell (1g-07) that transmits SIB1 in an on-demand manner can transmit a synchronization signal, SSB (Synchronization Signal / PBCH block, hereinafter referred to as SSB).

[0250] In step 1g-50, the terminal (1g-01) can perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection) The method for performing frequency measurement can follow the above-described embodiment (Fig. 1e).

[0251] In step 1g-55, the terminal (1g-01) can determine a candidate target cell that satisfies the cell reselection criteria based on the measurement values ​​performed in step 1g-50. (Evaluate cell reselection criteria) This can follow the embodiment described above (Fig. 1e).

[0252] Accordingly, a terminal according to an embodiment of the present disclosure may determine the final candidate target cell as NR cell (1g-07). That is, the NR cell (1g-07) may be the best cell or the highest ranked cell for the terminal (1g-01).

[0253] At step 1g-60, the terminal (1g-01) can identify whether a candidate target cell (1g-07) transmits SIB1 on-demand. (Identify whether a candidate target cell transmits SIB1 via on-demand) This can follow the embodiment described above (Fig. 1f).

[0254] At step 1g-65, the terminal (1g-01) may not have WUS configuration information to request SIB1 to be transmitted to the NR cell (1g-07). (No WUS configuration)

[0255] More specifically, the terminal (1g-01) may not receive WUS configuration information for requesting transmission of SIB1 to the NR cell (1g-07) in the 1g-20 step, the 1g-40 step, or the 1g-60 step.

[0256] At step 1g-70, the terminal (1g-01) may regard the NR cell (1g-07) as a barred cell as a candidate for cell selection / reselection for a predetermined period of time (exclude the barred cell as a candidate for cell selection / reselection for x or for up to x seconds).

[0257] The above terminal must obtain SIB1 in order to reselect the NR cell, but since it cannot transmit WUS, the NR cell can be prohibited as a barred cell.

[0258] In step 1g-75, the terminal (1g-01) can select and / or reselect a neighboring cell in the frequency to which the NR cell (1g-07) belongs through at least one of the following methods 1 to 3. (determine how to perform cell (re-)selection on the same frequency)

[0259] - Method 1: If the reselection condition is satisfied, a neighboring cell in the frequency to which the NR cell (1g-07) belongs can be selected. This is because the terminal can select or reselect a neighboring cell in the frequency to which the NR cell (1g-07) belongs. For example, the neighboring cell in the frequency to which the NR cell (1g-07) belongs may be a cell that periodically transmits SIB1, or the terminal may have WUS configuration information for the neighboring cell in the frequency to which the NR cell (1g-07) belongs, and thus can select or reselect the cell.

[0260] - Method 2: The terminal may select and / or reselect a neighboring cell in the frequency to which the NR cell (1g-07) belongs according to intraFreqReselection indicated in the MIB received from the NR cell (1g-07). If intraFreqReselection is not allowed, the terminal may not select and / or reselect a neighboring cell in the frequency to which the NR cell (1g-07) belongs for a predetermined period of time. For example, the predetermined period of time may be 300 seconds or at most 300 seconds. Otherwise, the terminal may select or reselect a neighboring cell in the frequency to which the NR cell (1g-07) belongs.

[0261] - Method 3: The neighboring cells in the frequency to which the NR cell (1g-07) belongs may not be selected or reselected for a predetermined period of time. For example, the predetermined period of time may be 300 seconds or up to 300 seconds. This is because the terminal may not be able to finally reselect a cell from neighboring cells in the frequency to which the NR cell (1g-07) belongs, as in step 1g-65.

[0262] FIG. 1h is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0263] According to one embodiment of the present disclosure, a given cell may periodically transmit essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0264] Additionally, a given cell according to an embodiment of the present disclosure, unlike the above-described embodiment (Fig. 1e), has a feature that transmits MIB periodically but can transmit SIB1 on-demand. This is because network energy can be saved by transmitting SIB1 when a terminal requests it. More specifically, when a terminal needs to acquire SIB1 for a given reason, it can request that SIB1 be broadcast / transmitted to a cell that does not transmit SIB1. The given reason may include a case of selecting and / or reselecting a cell. Accordingly, the cell that received the request can broadcast SIB1.

[0265] Referring to FIG. 1h, at step 1h-10, the terminal (1h-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with an NR cell (1h-05).

[0266] At step 1h-15, the terminal (1h-01) can transmit a terminal capability information message (UECapabilityInformation) to the NR cell (1h-05).

[0267] The above terminal capability information message may include capability information indicating that the terminal can transmit (or is capable of transmitting) a wake-up signal (hereinafter referred to as WUS), which is a signal for requesting a cell transmitting SIB1 on-demand to transmit SIB1. (Support of wake-up signal transmission for on-demand SIB1 delivery cell)

[0268] At step 1h-20, the NR cell (1h-05) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1h-01) in RRC connection mode.

[0269] The information included in the above message may follow at least one of the embodiments described above (Fig. 1e, Fig. 1h).

[0270] In step 1h-25, the terminal (1h-01) in the RRC connection mode can apply an RRC connection release message and then transition to the RRC idle mode (RRC_IDLE) or the RRC inactive mode (RRC_INACTIVE) as in the embodiment described above.

[0271] More specifically, if the RRC connection release message includes suspend configuration information (suspendConfig), the terminal can transition to RRC inactive mode (RRC_INACTIVE). On the other hand, if the message does not include suspend configuration information, the terminal can transition to RRC idle mode (RRC_IDLE). (RRC_IDLE or RRC_INACTIVE)

[0272] At step 1h-30, a terminal (1h-01) in RRC idle mode or RRC inactive state can acquire essential system information, MIB and SIB1, from an NR cell (1h-05).

[0273] In step 1h-35, the terminal (1h-01) may perform a cell selection procedure based on step 1h-30. This may follow the embodiment described above (Fig. 1e).

[0274] In step 1h-40, the terminal (1h-01) may acquire system information containing cell reselection information from the serving cell (1h-05) to perform a cell reselection evaluation procedure. For example, the system information may include SIB2, SIB3, SIB4, SIB5, and new SIB. This may follow at least one of the embodiments described above (FIG. 1e, FIG. 1h).

[0275] In step 1h-45, the terminal (1h-01) can determine the reselection priority for cell reselection. (Handle reselection priorities) The method for determining the reselection priority can follow the embodiment described above (Fig. 1e).

[0276] At step 1h-47, a cell (1h-07) transmitting SIB1 in an on-demand manner can transmit a synchronization signal, SSB (Synchronization Signal / PBCH block, hereinafter referred to as SSB).

[0277] In step 1h-50, the terminal (1h-01) can perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection) The method for performing frequency measurement can follow the above-described embodiment (Fig. 1e).

[0278] In step 1h-55, the terminal (1h-01) can determine a candidate target cell that satisfies the cell reselection criteria based on the measurement values ​​performed in step 1h-50. (Evaluate cell reselection criteria) This can follow the embodiment described above (Fig. 1e).

[0279] Accordingly, a terminal according to an embodiment of the present disclosure may determine the final candidate target cell as NR cell (1h-07). That is, the NR cell (1h-07) may be the best cell or the highest ranked cell for the terminal (1h-01).

[0280] At step 1h-60, the terminal (1h-01) can identify whether a candidate target cell (1h-07) transmits SIB1 on-demand. (Identify whether a candidate target cell transmits SIB1 via on-demand) This can follow the embodiment described above (Fig. 1h).

[0281] At step 1h-65, the terminal (1h-01) may not have WUS configuration information to request SIB1 to be transmitted to the NR cell (1h-07). (No WUS configuration)

[0282] More specifically, the terminal (1h-01) may not receive WUS configuration information to request transmission of SIB1 to the NR cell (1h-07) in step 1h-20, step 1h-40, or step 1h-60.

[0283] At step 1h-70, the terminal (1h-01) can determine the NR cell (1h-08), which is the second best cell or the second highest ranked cell that satisfies the cell reselection criteria.

[0284] At step 1h-75, the terminal (1h-01) can determine whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell (1h-08) satisfy the cell selection criterion (Srxlev > 0 AND Squal > 0) called S-criterion (see Equation 1, Example 1e described above) based on the essential system information (MIB and SIB1) received from the candidate target cell. (Before reselecting a candidate target cell, the UE reads system information from that cell and performs a final suitability check). If the S-criterion is satisfied and the candidate target cell is suitable, the terminal can re-select the concerned target cell. (If S-criterion is satisfied, re-select the concerned target cell)

[0285] FIG. 1i is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0286] According to one embodiment of the present disclosure, a given cell may periodically transmit essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0287] Additionally, a given cell according to an embodiment of the present disclosure, unlike the above-described embodiment (Fig. 1e), has the characteristic of transmitting MIB periodically, but can transmit SIB1 on-demand. This is because network energy can be saved by transmitting SIB1 when a terminal requests it. More specifically, when a terminal needs to acquire SIB1 for a given reason, it can request that SIB1 be broadcast / transmitted to a cell that does not transmit SIB1. The given reason may include a case of selecting and / or reselecting a cell. Accordingly, the cell that received the request can broadcast SIB1.

[0288] Referring to FIG. 1i, at step 1i-10, the terminal (1i-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with an NR cell (1i-05).

[0289] In step 1i-15, the terminal (1i-01) can transmit a terminal capability information message (UECapabilityInformation) to the NR cell (1i-05).

[0290] The above terminal capability information message may include capability information indicating that the terminal can transmit (or is capable of transmitting) a wake-up signal (hereinafter referred to as WUS), which is a signal for requesting a cell transmitting SIB1 on-demand to transmit SIB1. (Support of wake-up signal transmission for on-demand SIB1 delivery cell)

[0291] Additionally, the present disclosure may include an indicator indicating that the message has the ability (or indicates that it has) to apply a frequency consisting of a cell transmitting SIB1 on-demand or cells transmitting SIB1 on-demand with the lowest reselection priority.

[0292] In step 1i-20, the NR cell (1i-05) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1i-01) in RRC connection mode.

[0293] The information contained in the above message may follow at least one of the embodiments described above (Figs. 1e and 1i). Additionally, the message may include an instruction to apply a frequency composed of cells transmitting on-demand or cells transmitting SIB1 on-demand with the lowest reselection priority. Note that a timer value for the time for which the instruction is to be applied may also be included.

[0294] In step 1i-25, the terminal (1i-01) in the RRC connection mode can apply an RRC connection release message and then transition to the RRC idle mode (RRC_IDLE) or the RRC inactive mode (RRC_INACTIVE), as in the embodiment described above.

[0295] More specifically, if the RRC connection release message includes suspend configuration information (suspendConfig), the terminal can transition to RRC inactive mode (RRC_INACTIVE). On the other hand, if the message does not include suspend configuration information, the terminal can transition to RRC idle mode (RRC_IDLE). (RRC_IDLE or RRC_INACTIVE)

[0296] In step 1i-30, a terminal (1i-01) in RRC idle mode or RRC inactive state can acquire MIB and SIB1, which are essential system information, from an NR cell (1i-05).

[0297] In step 1i-35, the terminal (1i-01) may perform a cell selection procedure based on step 1i-30. This may follow the embodiment described above (Fig. 1e).

[0298] In step 1i-40, the terminal (1i-01) can obtain system information containing cell reselection information from the serving cell (1i-05) to perform a cell reselection evaluation procedure. For example, the system information can include SIB2, SIB3, SIB4, SIB5, and new SIB. This can follow at least one of the above-described embodiments (FIG. 1e, FIG. 1i). Additionally, in the present disclosure, a list of cells transmitting SIB1 on-demand or a frequency list composed of cells transmitting SIB1 on-demand can be included in the system information.

[0299] In step 1i-45, the terminal (1i-01) can determine the reselection priority for cell reselection. (Handle reselection priorities) The method for determining the reselection priority can follow the above-described embodiment (Fig. 1e). The terminal (1i-01) according to the present disclosure can determine the cell(s) transmitting SIB1 on-demand or the frequency(s) composed of cells transmitting SIB1 on-demand as having the lowest reselection priority. This can help save energy at the base station by preventing the terminal from reselecting cells transmitting SIB1 on-demand as much as possible.

[0300] In step 1i-47, a cell (1i-07) transmitting SIB1 in an on-demand manner can transmit a synchronization signal, SSB (Synchronization Signal / PBCH block, hereinafter referred to as SSB).

[0301] In step 1i-50, the terminal (1i-01) can perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection) The method for performing frequency measurement can follow the above-described embodiment (Fig. 1e).

[0302] In step 1i-55, the terminal (1i-01) can determine a candidate target cell that satisfies the cell reselection criteria based on the measurement values ​​performed in step 1i-50. (Evaluate cell reselection criteria) This can follow the embodiment described above (Fig. 1e).

[0303] Accordingly, the terminal according to one embodiment of the present disclosure may determine the final candidate target cell as the NR cell (1i-07). That is, the NR cell (1i-07) may be the best cell or the highest ranked cell for the terminal (1i-01).

[0304] At step 1i-60, the terminal (1i-01) can identify whether a candidate target cell (1i-07) transmits SIB11 on-demand. (Identify whether a candidate target cell transmits SIB11 via on-demand) This can follow the embodiment described above (Fig. 1f).

[0305] At step 1i-65, the terminal (1i-01) can transmit a wake-up signal (WUS) to receive SIB1 from the NR cell (1i-07). (No WUS configuration)

[0306] More specifically, the terminal (1i-01) can transmit WUS based on WUS setting information received in step 1i-20, step 1i-40, or step 1i-60.

[0307] In step 1i-70, the NR cell (1i-07) can transmit SIB1, and the terminal (1i-01) can receive it. For reference, the terminal (1i-01) can receive the MIB transmitted by the NR cell (1i-07) in step 1i-70 or in a previous step. The previous step may include step 1i-55 or step 1i-60.

[0308] At step 1i-75, the terminal (1i-01) can determine whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell (1i-07) satisfy the cell selection criterion (Srxlev > 0 AND Squal > 0) called S-criterion (Mathematical Formula 1) based on the essential system information (e.g., MIB and SIB1) received from the candidate target cell (1i-07). (UE performs a final suitability check).

[0309] [Mathematical Formula 1]

[0310] Srxlev > 0 AND Squal > 0

[0311] where

[0312] Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset ) - P compensation - -Qoffset temp,

[0313] Squal = Q qualmeas - (Q qualmin + Q qualminoffset ) - Qoffset temp.

[0314] The terminal can re-select the candidate target cell if the S-criterion is satisfied and the candidate target cell is suitable. (If S-criterion is satisfied, re-select the concerned target cell)

[0315] FIG. 1J is a diagram illustrating a procedure for a terminal in an RRC idle mode (RRC_IDLE) or an RRC inactive state (RRC_INACTIVE) to reselect a cell for transmitting System Information Block 1 (SIB1) on-demand according to one embodiment of the present disclosure.

[0316] According to one embodiment of the present disclosure, a given cell may periodically transmit essential system information, which refers to a Master Information Block (MIB) and a System Information Block 1 (SIB1). The essential system information includes configuration information required for a terminal to select or camp on a cell.

[0317] Additionally, a given cell according to the present disclosure, unlike the aforementioned embodiment (Fig. 1e), has the characteristic of transmitting MIB periodically, but can transmit SIB1 on-demand. This is because network energy can be saved by transmitting SIB1 when a terminal requests it. More specifically, if a terminal needs to acquire SIB1 for a given reason, it can request that SIB1 be broadcast / transmitted to a cell that does not transmit SIB1. The given reason may include a case where it is for selecting and / or reselecting a cell. Accordingly, the cell that received the request can broadcast SIB1.

[0318] Referring to FIG. 1j, in step 1j-10, the terminal (1j-01) may be in RRC connected mode (RRC_CONNECTED) by establishing an RRC connection with an NR cell (1j-05).

[0319] In step 1j-15, the terminal (1j-01) can transmit a terminal capability information message (UECapabilityInformation) to the NR cell (1j-05).

[0320] The above terminal capability information message may include capability information indicating that the terminal can transmit (or is capable of transmitting) a wake-up signal (hereinafter referred to as WUS), which is a signal for requesting a cell transmitting SIB1 on-demand to transmit SIB1. (Support of wake-up signal transmission for on-demand SIB1 delivery cell)

[0321] In step 1j-20, the NR cell (1j-05) may transmit an RRC connection release message (RRCRelease) to release the RRC connection with the terminal (1j-01) in RRC connection mode. The information included in the message may at least follow the aforementioned embodiments. Additionally, the message may include at least one of the following:

[0322] - An indicator indicating whether the above terminal (1j-01) can transmit WUS.

[0323] - Setting information required when the above terminal (1j-01) transmits WUS

[0324] ■ The above setting information can be set by frequency or by cell per frequency.

[0325] ■ The above configuration information may refer to one or more random access preambles. For example, it may refer to a preamble indicating the first message (Msg1) sent during a random access procedure.

[0326] ■ The above configuration information may refer to one or more random access opportunities (PRACH occasions) for transmitting a preamble. For example, a RACH occasion may refer to an indication of a frequency / time at which a preamble will be transmitted during a random access procedure.

[0327] The terminal (1j-01) in the RRC connection mode can transition (1j-25) to the RRC idle mode (RRC_IDLE) or RRC inactive mode (RRC_INACTIVE) as in the embodiment described above after applying the RRC connection release message.

[0328] In step 1j-30, a terminal (1j-01) in RRC idle mode or RRC inactive state can acquire essential system information, MIB and SIB1, from an NR cell (1j-05).

[0329] In step 1j-35, the terminal (1j-01) may perform a cell selection procedure based on step 1j-30. This may follow at least one of the embodiments described above.

[0330] In step 1j-40, the terminal (1j-01) may acquire system information containing cell reselection information from the serving cell (1j-05) to perform a cell reselection evaluation procedure. For example, the system information may include SIB2, SIB3, SIB4, SIB5, and new SIB. This may follow at least one of the embodiments described above.

[0331] Additionally, the present disclosure proposes that a list of cells transmitting SIB1 on-demand for each frequency be signaled in the system information. Specifically, a list of cells for each frequency may be broadcast in the system information, which may refer to a list of cells transmitting SIB1 on-demand. In this case, cell reselection parameters applicable to the S criterion and / or the R criterion may be signaled separately. For example, parameters applicable to cells transmitting SIB1 on-demand may refer to at least one of the following:

[0332] - At least one of q-RxLevmin, q-QualMin, qRxLevMinOffsetCell, q-QualMinOffsetCell applied to S criterion

[0333] - q-OffsetCell applied to R criterion

[0334] In step 1j-45, the terminal (1j-01) can determine the reselection priority for cell reselection. (Handle reselection priorities) This can follow the embodiment described above (Fig. 1e).

[0335] In step 1j-47, a cell (1j-07) transmitting SIB1 in an on-demand manner can transmit a synchronization signal, SSB (Synchronization Signal / PBCH block, hereinafter referred to as SSB).

[0336] In step 1j-50, the terminal (1j-01) may perform frequency measurement for cell reselection. (Perform measurement by using measurement rules for cell reselection) This may follow the embodiment described above (Fig. 1e).

[0337] In step 1j-55, the terminal (1j-01) can determine a candidate target cell that satisfies the cell reselection criteria based on the measurement value performed in step 1j-50. (Evaluate cell reselection criteria) This may follow the embodiment described above (Fig. 1e). At this time, the parameter described above in step 1j-40 can be applied to determine a candidate target cell that satisfies the cell reselection criteria. Accordingly, the terminal according to the present disclosure can determine the final candidate target cell as the NR cell (1j-07). That is, the NR cell (1j-07) may be a best cell or a highest-ranked cell for the terminal (1j-01).

[0338] At step 1j-60, the terminal (1j-01) can identify whether a candidate target cell (1j-07) transmits SIB1 on-demand. This can follow at least one of the embodiments described above.

[0339] At step 1j-65, the terminal (1j-01) may transmit a wake-up signal (WUS) to receive SIB1 from the NR cell (1j-07). This may follow at least one of the embodiments described above.

[0340] At step 1j-70, the NR cell (1j-07) can transmit SIB1, and the terminal (1j-01) can receive it. For reference, the terminal (1j-01) can receive the MIB transmitted by the NR cell (1j-07) at step 1j-70 or at a previous step. The previous step may include step 1j-55 or step 1j-60.

[0341] At step 1j-75, the terminal (1j-01) can determine whether the reception level (Srxlev) and reception quality (Squal) of the candidate target cell (1j-07) satisfy the cell selection criterion (Srxlev > 0 AND Squal > 0) referred to as S-criterion (Mathematical Formula 1) based on the essential system information (e.g., MIB and SIB1) received from the candidate target cell. (UE performs a final suitability check.)

[0342] [Mathematical Formula 1]

[0343] Srxlev > 0 AND Squal > 0

[0344] where

[0345] Srxlev = Q rxlevmeas - (Q rxlevmin + Q rxlevminoffset ) - P compensation - -Qoffset temp,

[0346] Squal = Q qualmeas - (Q qualmin + Q qualminoffset ) - Qoffset temp.

[0347] The terminal can re-select the concerned target cell if the S-criterion is satisfied and the candidate target cell is suitable. (If S-criterion is satisfied, re-select the concerned target cell)

[0348] FIG. 1k is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present disclosure.

[0349] Referring to the above drawing, the terminal includes an RF (Radio Frequency) processing unit (1k-10), a baseband processing unit (1k-20), a storage unit (1k-30), and a control unit (1k-40).

[0350] The RF processing unit (1k-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (1k-10) up-converts the baseband signal provided from the baseband processing unit (1k-20) 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 (1k-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In the drawing, only one antenna is illustrated, but the terminal may be equipped with multiple antennas. In addition, the RF processing unit (1k-10) may include multiple RF chains. Furthermore, the RF processing unit (1k-10) may perform beamforming. For the above beamforming, the RF processing unit (1k-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. In addition, the RF processing unit can perform MIMO and receive multiple layers when performing the MIMO operation.

[0351] The baseband processing unit (1k-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the baseband processing unit (1k-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (1k-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (1k-10). For example, in the case of following the OFDM (orthogonal frequency division multiplexing) method, when transmitting data, the baseband processing unit (1k-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols by performing an inverse fast Fourier transform (IFFT) operation and inserting a cyclic prefix (CP). In addition, when receiving data, the baseband processing unit (1k-20) divides the baseband signal provided from the RF processing unit (1k-10) into OFDM symbol units, restores signals mapped to subcarriers through FFT (fast Fourier transform), and then restores the received bit string through demodulation and decoding.

[0352] The baseband processing unit (1k-20) and the RF processing unit (1k-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (1k-20) and the RF processing unit (1k-10) may be referred to as a transmitter, a receiver, a transceiver, or a communication unit. Furthermore, at least one of the baseband processing unit (1k-20) and the RF processing unit (1k-10) may include a plurality of communication modules to support a plurality of different wireless access technologies. In addition, at least one of the baseband processing unit (1k-20) and the RF processing unit (1k-10) may include different communication modules to process signals of different frequency bands. For example, the different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), etc. Additionally, the different frequency bands may include a super high frequency (SHF) (e.g., 2.NRHz, NRhz) band and a millimeter wave (mm wave) (e.g., 60GHz) band.

[0353] The storage unit (1k-30) stores data such as basic programs, application programs, and setting information for the operation of the terminal. In particular, the storage unit (1k-30) can store information related to a second access node that performs wireless communication using a second wireless access technology. In addition, the storage unit (1k-30) provides the stored data at the request of the control unit (1k-40).

[0354] The control unit (1k-40) controls the overall operations of the terminal. For example, the control unit (1k-40) transmits and receives signals through the baseband processing unit (1k-20) and the RF processing unit (1k-10). In addition, the control unit (1k-40) records and reads data in the storage unit (1k-40). For this purpose, the control unit (1k-40) may include at least one processor. For example, the control unit (1k-40) may include a communication processor (CP) that performs control for communication and an application processor (AP) that controls upper layers such as application programs.

[0355] FIG. 1l is a block diagram illustrating the internal structure of a New Radio (NR) base station according to one embodiment of the present disclosure.

[0356] As shown in the above drawing, the base station is configured to include an RF processing unit (1l-10), a baseband processing unit (1l-20), a backhaul communication unit (1l-30), a storage unit (1l-40), and a control unit (1l-50).

[0357] The RF processing unit (11-10) performs functions for transmitting and receiving signals through a wireless channel, such as signal band conversion and amplification. That is, the RF processing unit (11-10) up-converts the baseband signal provided from the baseband processing unit (11-20) 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 (11-10) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc. In the drawing, only one antenna is shown, but the first access node may have multiple antennas. In addition, the RF processing unit (11-10) may include multiple RF chains. Furthermore, the RF processing unit (11-10) may perform beamforming. For the above beamforming, the RF processing unit (11-10) can adjust the phase and size of each signal transmitted and received through multiple antennas or antenna elements. The RF processing unit can perform a downlink MIMO operation by transmitting one or more layers.

[0358] The baseband processing unit (11-20) performs a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the first wireless access technology. For example, when transmitting data, the baseband processing unit (11-20) generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the baseband processing unit (11-20) restores the reception bit stream by demodulating and decoding the baseband signal provided from the RF processing unit (11-10). For example, in the case of OFDM, when transmitting data, the baseband processing unit (11-20) generates complex symbols by encoding and modulating a transmission bit stream, maps the complex symbols to subcarriers, and then configures OFDM symbols through IFFT operation and CP insertion. In addition, when receiving data, the baseband processing unit (11-20) divides the baseband signal provided from the RF processing unit (11-10) into OFDM symbol units, restores the signals mapped to subcarriers through FFT operation, and then restores the received bit string through demodulation and decoding. The baseband processing unit (11-20) and the RF processing unit (11-10) transmit and receive signals as described above. Accordingly, the baseband processing unit (11-20) and the RF processing unit (11-10) may be referred to as a transmitter, a receiver, a transceiver, a communication unit, or a wireless communication unit.

[0359] The above backhaul communication unit (1l-30) provides an interface for performing communication with other nodes within the network. That is, the backhaul communication unit (1l-30) converts a bit string transmitted from the main base station to another node, such as an auxiliary base station or core network, into a physical signal, and converts a physical signal received from the other node into a bit string.

[0360] The storage unit (11-40) stores data such as basic programs, application programs, and setting information for the operation of the main base station. In particular, the storage unit (11-40) can store information on bearers assigned to connected terminals, measurement results reported from connected terminals, and the like. In addition, the storage unit (11-40) can store information that serves as a judgment criterion for whether to provide or terminate multiple connections to a terminal. In addition, the storage unit (11-40) provides the stored data at the request of the control unit (11-50).

[0361] The control unit (11-50) controls the overall operations of the base station. For example, the control unit (11-50) transmits and receives signals through the baseband processing unit (11-20) and the RF processing unit (11-10) or through the backhaul communication unit (11-30). In addition, the control unit (11-50) records and reads data in the storage unit (11-40). For this purpose, the control unit (11-50) may include at least one processor.

[0362] The methods according to the embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

[0363] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present invention.

[0364] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0365] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present invention via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present invention.

[0366] In this disclosure, the term "computer program product" or "computer-readable medium" is used to collectively refer to media such as memory, a hard disk installed in a hard disk drive, and signals. These "computer program products" or "computer-readable mediums" are components provided in a method for reporting terminal capabilities in a wireless communication system according to the present disclosure.

[0367] A device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0368] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be temporarily stored or temporarily generated in a machine-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0369] In the specific embodiments of the present invention described above, components included in the invention are expressed in the singular or plural form depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present invention is not limited to singular or plural components. Even components expressed in the plural form may be composed of singular elements, or even components expressed in the singular form may be composed of plural elements.

[0370] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims but also by equivalents thereof.

Claims

1. In a method performed by a terminal in a wireless communication system, A step of receiving at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information from a serving cell; A step of determining a final candidate target cell based on the above cell reselection priority setting information; A step of determining whether the final candidate target cell is a cell that supports System Information Block 1 (SIB1) on-demand based on the above WUS configuration information; A step of transmitting WUS to the final candidate target cell when the final candidate target cell determined above is a cell supporting SIB1 on-demand; In response to the WUS transmission, receiving SIB1 from the final candidate target cell; and A method characterized by comprising a step of determining whether to perform cell reselection as the final candidate target cell based on the SIB1.

2. In paragraph 1, A method characterized in that, if the final candidate target cell determined above is a cell that does not support SIB1 on-demand, the final candidate target cell is determined as a barred cell.

3. In paragraph 1, A method characterized in that the above WUS setting information is set in units of cell (Physical Cell Identity, PCI) and frequency.

4. In paragraph 1, The above system information includes any one of System Information Block 2 (SIB 2), SIB3, SIB4, SIB5, or new SIB, A method characterized in that the above WUS configuration information includes configuration information related to transmission of a random access preamble.

5. A method performed by a base station supporting a serving cell in a wireless communication system, A step of transmitting a Master Information Block (MIB) and a System Information Block 1 (SIB1) to the terminal; and A step of transmitting at least one piece of system information including at least one piece of cell reselection priority setting information and Wake Up Signal (WUS) setting information to the terminal, The above WUS setting information is used to determine whether the final candidate target cell determined based on the cell reselection priority setting information is a cell that supports System Information Block 1 (SIB1) on-demand. If the final candidate target cell is a cell that supports SIB1 on-demand, the final candidate target cell transmits SIB1 to the terminal in response to the WUS. A method characterized in that the above SIB1 is used to determine whether to perform cell reselection to the final candidate target cell.

6. In paragraph 5, A method characterized in that if the final candidate target cell is a cell that does not support SIB1 on-demand, the final candidate target cell is determined as a barred cell.

7. In paragraph 5, A method characterized in that the above WUS setting information is set in units of cell (Physical Cell Identity, PCI) and frequency.

8. In paragraph 5, The above system information includes any one of System Information Block 2 (SIB 2), SIB3, SIB4, SIB5, or new SIB, A method characterized in that the above WUS configuration information includes configuration information related to transmission of a random access preamble.

9. In a wireless communication system, at the terminal, A transceiver for transmitting and receiving signals; and It includes a control unit, wherein the control unit is: Receive at least one piece of system information from a serving cell, including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information, Based on the above cell reselection priority setting information, the final candidate target cell is determined, Based on the above WUS configuration information, it is determined whether the final candidate target cell is a cell that supports System Information Block 1 (SIB1) on-demand, If the final candidate target cell determined above is a cell that supports SIB1 on-demand, WUS is transmitted to the final candidate target cell. In response to the above WUS transmission, SIB1 is received from the final candidate target cell, A terminal characterized in that it determines whether to perform cell reselection as the final candidate target cell based on the above SIB1.

10. In paragraph 9, the control unit, A terminal characterized in that, if the final candidate target cell determined above is a cell that does not support SIB1 on-demand, the final candidate target cell is determined as a barred cell.

11. In paragraph 9, A terminal characterized in that the above WUS setting information is set in units of cell (Physical Cell Identity, PCI) and frequency.

12. In paragraph 9, The above system information includes any one of System Information Block 2 (SIB 2), SIB3, SIB4, SIB5, or new SIB, A terminal characterized in that the above WUS configuration information includes configuration information related to transmission of a random access preamble.

13. In a base station supporting a serving cell in a wireless communication system, A transceiver for transmitting and receiving signals; and It includes a control unit, wherein the control unit is: Transmitting a Master Information Block (MIB) and a System Information Block 1 (SIB1) to the terminal, Transmitting at least one piece of system information including at least one piece of cell reselection priority setting information or Wake Up Signal (WUS) setting information to the terminal, The above WUS configuration information is used to determine whether the final candidate target cell determined based on the cell reselection priority information is a cell that supports System Information Block 1 (SIB1) on-demand. If the final candidate target cell is a cell that supports SIB1 on-demand, the final candidate target cell transmits SIB1 to the terminal in response to the WUS. A base station characterized in that the above SIB1 is used to determine whether to perform cell reselection to the final candidate target cell.

14. In paragraph 13, A base station, characterized in that if the final candidate target cell is a cell that does not support SIB1 on-demand, the final candidate target cell is determined as a barred cell.

15. In paragraph 13, The above WUS setting information is set in units of cell (Physical Cell Identity, PCI) and frequency. The above system information includes any one of System Information Block 2 (SIB 2), SIB3, SIB4, SIB5, or new SIB, A base station characterized in that the above WUS configuration information includes configuration information related to transmission of a random access preamble.

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