Method and device for energy saving in wireless communication system

Abstract

A method of a terminal of the present disclosure comprises the steps of: identifying whether a suitable cell exists by performing a cell reselection evaluation procedure when traffic occurs or signal quality (RSRP / RSRQ) is degraded; when the evaluation procedure is performed on the basis of traffic occurrence, switching to a connected mode if the suitable cell exists; and activating a deactivated data cell if the suitable cell does not exist.

Description

Method and device for energy saving in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more specifically to a method and apparatus for energy saving of a base station in a wireless communication system.

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

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

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

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

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

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

[0008] The present disclosure provides a method and apparatus for energy saving in a wireless communication system.

[0009] The technical problems to be solved by the present disclosure are not limited to those mentioned above, and other unmentioned technical problems may be considered by those skilled in the art from the various embodiments of the present disclosure described below.

[0010] A method of a terminal in a communication system according to an embodiment of the present disclosure for achieving the aforementioned technical problem comprises: a step of performing a cell reselection evaluation procedure; a step of identifying whether a suitable cell exists based on the cell reselection evaluation procedure; and a step of operating based on whether a suitable cell exists, wherein the existence of a suitable cell is identified based on the cell reselection evaluation procedure, and the cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, or based on a trigger that occurs when the first RSRP (reference signal received power) or first RSRQ (reference signal received quality) of a serving cell is lower than a threshold value, and the suitable cell satisfies a specific condition, and when the cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, the step of operating based on whether a suitable cell exists may include: a step of the terminal connecting to the suitable cell and switching to a connected state (connected mode) if the suitable cell exists; and a step of activating a deactivated data cell if the suitable cell does not exist.

[0011] A terminal of a communication system according to one embodiment of the present disclosure comprises: at least one transceiver; and at least one processor connected to the at least one transceiver so as to be able to communicate with the at least one transceiver. The device is connected to communicate with at least one processor and is executable individually or in any combination of the at least one processors, and includes a memory that stores instructions for the terminal to perform a cell reselection evaluation procedure, identify whether a suitable cell exists based on the cell reselection evaluation procedure, and operate based on whether a suitable cell exists. The cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, or based on a trigger that occurs when the first RSRP (reference signal received power) or first RSRQ (reference signal received quality) of a serving cell is lower than a threshold value. The suitable cell satisfies a specific condition. When the cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, the memory that stores instructions for operating based on whether a suitable cell exists may store instructions for the terminal to connect to the suitable cell and switch to a connected state (connected mode), and for the terminal to activate a deactivated data cell if the suitable cell does not exist.

[0012] According to one embodiment of the present disclosure, by defining a signal transmission method of a base station in a wireless communication system, the problem of excessive energy consumption can be resolved and high energy efficiency can be achieved.

[0013] The effects obtainable from the various embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art based on the following detailed description.

[0014] FIG. 1 is a diagram showing the basic structure of the time-frequency resource domain of a 5G system according to one embodiment of the present disclosure.

[0015] FIG. 2 is a diagram showing a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0016] FIG. 3 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure.

[0017] FIG. 4 is a diagram illustrating a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure.

[0018] FIG. 5 is a diagram showing a Control Resource Set (CORESET) as a time-frequency resource to which a PDCCH is mapped according to one embodiment of the present disclosure.

[0019] FIG. 6 is a diagram showing the mapping of DCI and DMRS in REG, which is the basic unit of a downlink control channel according to one embodiment of the present disclosure.

[0020] FIG. 7 is a diagram showing base station beam allocation according to TCI state setting according to one embodiment of the present disclosure.

[0021] FIG. 8 is a diagram illustrating a hierarchical signaling method for dynamic allocation of a PDCCH beam of NR according to one embodiment of the present disclosure.

[0022] FIG. 9 is a diagram showing a TCI indication MAC CE signaling structure for a PDCCH DMRS according to one embodiment of the present disclosure.

[0023] FIG. 10 is a diagram illustrating a method for transmitting and receiving data by a base station and a terminal in consideration of a downlink data channel and rate matching resources according to one embodiment of the present disclosure.

[0024] FIG. 11 is a diagram illustrating a non-periodic CSI reporting method when the CSI-RS offset is 0 according to one embodiment of the present disclosure.

[0025] FIG. 12 is a diagram illustrating a non-periodic CSI reporting method when the CSI-RS offset is 1 according to one embodiment of the present disclosure.

[0026] FIG. 13 is a diagram showing the settings for a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

[0027] FIG. 14 is a diagram showing Discontinuous Reception (DRX) in a 5G communication system according to one embodiment of the present disclosure.

[0028] FIG. 15 is a drawing for illustrating an existing network communication system to which an embodiment of the present disclosure is applicable.

[0029] FIG. 16a is a drawing showing an example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0030] FIG. 16b is a drawing showing another example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0031] FIG. 17a is a drawing showing an example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0032] FIG. 17b is a drawing showing another example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0033] FIG. 18 is a diagram showing the procedure of a terminal camping on in a cell structure of an existing network communication system to which an embodiment of the present disclosure is applicable.

[0034] FIG. 19 is a diagram showing the procedure of a terminal camping on in a cell structure of a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0035] Figure 20 is a diagram showing the state and state transition of a terminal of the existing technology.

[0036] Figure 21 is a diagram showing the new state and state transition of the terminal.

[0037] FIG. 22a is a diagram showing an example of a method for indicating a dynamic cell list or frequency band.

[0038] FIG. 22b is a diagram showing another example of a method for indicating a dynamic cell list or frequency band.

[0039] FIG. 23 is a drawing showing a terminal transceiver device according to one embodiment of the present disclosure.

[0040] FIG. 24 is a diagram showing the configuration of a terminal according to one embodiment of the present disclosure.

[0041] FIG. 25 is a diagram showing the configuration of a base station according to one embodiment of the present disclosure.

[0042] For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description.

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known functions or configurations might unnecessarily obscure the essence of the present disclosure, such detailed description will be omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0044] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, like reference numerals refer to like components.

[0045] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0046] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0047] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0048] In describing the present disclosure below, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present disclosure. Embodiments of the present disclosure will be described below with reference to the attached drawings.

[0049] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0050] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0051] In the present disclosure, upper layer signaling refers to a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel. Upper layer signaling may be understood as radio resource control (RRC) signaling or a media access control (MAC) control element (CE).

[0052] For convenience of explanation, the present disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th generation mobile communication standard) specifications. However, the present disclosure is not limited by the above terms and names and may be applied equally to systems conforming to other standards. Additionally, the term "terminal" may refer to mobile phones, smartphones, IoT devices, sensors, as well as other wireless communication devices.

[0053] Hereinafter, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, eNB, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. The terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Of course, it is not limited to the above examples.

[0054] 5G (5 thInitial standards for the Generation) system or New Radio access technology (NR) have been completed. While existing mobile communication systems focused on conventional voice / data communication, 5G systems aim to satisfy various services and requirements, such as enhanced Mobile BroadBand (eMBB) services to improve existing voice / data communication, Ultra-Reliable and Low Latency Communication (URLLC) services, and massive Machine Type Communication (MTC) services to support mass communication of the Internet of Things.

[0055] While the transmission bandwidth per carrier in existing LTE and LTE-A is limited to a maximum of 20 MHz, 5G systems aim to provide ultra-high-speed data services reaching several Gbps by utilizing significantly wider ultra-wide bandwidth. Accordingly, 5G systems are considering ultra-high frequency bands ranging from several GHz to up to 100 GHz as candidate frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, it is possible to secure wide bandwidth frequencies for 5G systems through frequency reallocation or allocation from frequency bands ranging from several hundred MHz to several GHz currently used by existing mobile communication systems.

[0056] The above-mentioned radio waves in the ultra-high frequency band have wavelengths of several millimeters and are also called millimeter waves (mmWave). However, in the ultra-high frequency band, path loss of radio waves increases in proportion to the frequency band, and the coverage of mobile communication systems becomes smaller.

[0057] To overcome the disadvantage of reduced coverage in the aforementioned ultra-high frequency band, beamforming technology can be applied to increase the reach of radio waves by using multiple antennas to concentrate the radiated energy of the radio waves toward a predetermined target point. That is, a signal to which the beamforming technology is applied has a relatively narrow beam width, and as radiated energy is concentrated within this narrowed beam width, the reach of the radio waves is increased. The beamforming technology can be applied to both the transmitting end and the receiving end. In addition to the effect of increasing coverage, beamforming technology has the effect of reducing interference in areas outside the beamforming direction. For the beamforming technology to operate properly, accurate measurement and feedback methods for the transmit and receive beams are required. The beamforming technology can be applied to a control channel or data channel that corresponds one-to-one between a predetermined terminal and a base station. In addition, beamforming technology may be applied to common signals transmitted by a base station to multiple terminals within the system, such as synchronization signals, physical broadcast channels (PBCH), control channels for transmitting system information, and data channels, to increase coverage. When beamforming technology is applied to common signals, beam sweeping technology, which changes the beam direction to transmit the signal, is additionally applied to ensure that the common signal reaches terminals located at any position within the cell.

[0058] Another requirement for 5G systems is ultra-low latency services, where the transmission delay between the transmitter and receiver is approximately 1ms. As a measure to reduce transmission delay, it is necessary to design a frame structure based on a short TTI (Transmission Time Interval) that is shorter than that of LTE and LTE-A. TTI is the basic time unit for performing scheduling, and the TTI of existing LTE and LTE-A systems is 1ms, which corresponds to the length of one subframe. For example, to satisfy the requirements for ultra-low latency services in the aforementioned 5G systems, short TTIs such as 0.5ms, 0.25ms, and 0.125ms, which are shorter than those of existing LTE and LTE-A systems, are possible.

[0059] FIG. 1 is a diagram showing the basic structure of a time-frequency resource domain of a 5G system according to one embodiment of the present disclosure. That is, FIG. 1 is a diagram showing the basic structure of a time-frequency resource domain, which is a wireless resource domain where data or control channels of a 5G system are transmitted.

[0060] Referring to FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit of a 5G system in the time domain is an OFDM (Orthogonal Frequency Division Multiplexing) symbol, (102) symbols are combined to form one slot (106), and A number of slots can be combined to form a single subframe (105). The length of the subframe is 1.0 ms, and 10 subframes can be combined to form a 10 ms frame (114). The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the total system transmission bandwidth is a total It can be composed of (104) subcarriers.

[0061] In the time-frequency domain, the basic unit of a resource is a resource element (RE) (112), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB or Physical Resource Block, PRB) is in the frequency domain. It can be defined as (110) consecutive subcarriers. In a 5G system And, the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0062] In a 5G system, base stations map data in RB units, and generally, scheduling can be performed on RBs that constitute one slot for a given terminal. That is, in a 5G system, the basic time unit for which scheduling is performed is a slot, and the basic frequency unit for which scheduling is performed can be an RB.

[0063] OFDM symbol count It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols; for example, if a normal CP is applied , when Extended CP is applied Extended CP can be applied to systems with relatively longer transmission distances than standard CP, allowing orthogonality between symbols to be maintained. In the case of standard CP, the ratio of CP length to symbol length is maintained at a constant value, so the overhead caused by CP can remain constant regardless of the subcarrier spacing. That is, if the subcarrier spacing is small, the symbol length increases, and consequently, the CP length can also increase. Conversely, if the subcarrier spacing is large, the symbol length decreases, and consequently, the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0064] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to satisfy diverse services and requirements. For example,

[0065] From the perspective of the operating frequency band, a larger subcarrier spacing is advantageous for recovering phase noise in the high-frequency band.

[0066] - From the perspective of transmission time, a large subcarrier spacing shortens the symbol length in the time domain, and consequently shortens the slot length, which is advantageous for supporting ultra-low latency services such as URLLC.

[0067] - From the perspective of cell size, a longer CP length allows for the support of larger cells, so a smaller subcarrier spacing allows for the support of relatively larger cells. A cell is a concept in mobile communication that refers to the area covered by a single base station.

[0068] The aforementioned subcarrier spacing, CP length, etc., are essential information for OFDM transmission and reception; therefore, smooth transmission and reception are possible only when the base station and the terminal recognize the subcarrier spacing, CP length, etc., as common values. [Table 1] shows the subcarrier spacing configurations supported by 5G systems. ), subcarrier interval ( It represents the relationship between ), and CP length.

[0069] [Table 1]

[0070]

[0071] [Table 2] shows the subcarrier spacing settings for the standard CP ( ) By category, number of symbols per slot ( ), number of slots per frame ( ), number of slots per subframe ( It represents ).

[0072]

[0073] [Table 3] shows the subcarrier spacing settings for extended CP ( ) By category, number of symbols per slot ( ), number of slots per frame ( ), number of slots per subframe ( It represents ).

[0074] [Table 3]

[0075]

[0076] In the early stages of introducing 5G systems, coexistence or dual-mode operation with at least existing LTE or / and LTE-A (hereinafter LTE / LTE-A) systems is expected. This allows existing LTE / LTE-A to provide stable system operation to terminals, while the 5G system can perform the role of providing enhanced services to said terminals. Therefore, the frame structure of the 5G system needs to include at least the frame structure or essential parameter set of LTE / LTE-A (subcarrier spacing = 15kHz).

[0077] For example, subcarrier spacing setting In-frame structure (hereinafter Frame Structure A) and subcarrier spacing setting When comparing the in-frame structure (hereinafter frame structure B), compared to frame structure A, frame structure B has a subcarrier spacing and RB size that are twice as large, and a slot length and symbol length that are twice as small. In the case of frame structure B, two slots can be configured into one subframe, and 20 subframes can be configured into one frame.

[0078] Generalizing the frame structure of the above 5G system, high scalability is provided by ensuring that the essential parameter sets, such as subcarrier spacing, CP length, and slot length, have an integer multiple relationship with each other for each frame structure. Additionally, a subframe of a fixed length of 1ms can be defined to represent a reference time unit independent of the frame structure.

[0079] The above frame structure can be applied in response to various scenarios. From the perspective of cell size, since a longer CP length allows for the support of larger cells, the above frame structure A can support relatively larger cells compared to the above frame structure B. From the perspective of operating frequency band, since a larger subcarrier spacing is advantageous for recovering phase noise in the high-frequency band, the above frame structure B can support relatively higher operating frequencies compared to the above frame structure A. From the perspective of service, since a shorter slot length, which is the basic time unit of scheduling, is advantageous for supporting ultra-low latency services such as URLLC, the above frame structure B can be relatively more suitable for URLLC services compared to the above frame structure A.

[0080] In the following description of the present disclosure, an uplink (UL) refers to a wireless link through which a terminal transmits data or control signals to a base station, and a downlink (DL) may refer to a wireless link through which a base station transmits data or control signals to a terminal.

[0081] In the initial access phase, when the terminal first connects to the system, the terminal can synchronize downlink time and frequency from the synchronization signal transmitted by the base station through cell search and obtain a cell identifier (cell ID). Then, the terminal can use the obtained cell ID to receive a Physical Broadcast Channel (PBCH) and obtain a Master Information Block (MIB), which is essential system information, from the PBCH. Additionally, the terminal can receive a System Information Block (SIB) transmitted by the base station to obtain cell-common transmission and reception control information. The cell-common transmission and reception control information may include random access control information, paging control information, and common control information for various physical channels.

[0082] The synchronization signal serves as a reference for cell search, and subcarrier spacing can be applied for each frequency band to suit channel environments such as phase noise. In the case of data channels or control channels, as described above, subcarrier spacing may be applied differently depending on the service type to support various services.

[0083] FIG. 2 is a diagram showing a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0084] For the purpose of explanation, the following components may be defined.

[0085] - PSS (Primary Synchronization Signal): A signal that serves as the reference for DL ​​time / frequency synchronization and provides some cell ID information.

[0086] - SSS (Secondary Synchronization Signal): Serves as a reference for DL ​​time / frequency synchronization and provides some of the remaining information, including the cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0087] - PBCH (Physical Broadcast Channel): Provides the Master Information Block (MIB), which is essential system information required for the transmission and reception of the terminal's data and control channels. The said essential system information may include control information related to the search space representing wireless resource mapping information of the control channel, scheduling control information for a separate data channel transmitting system information, and information such as the System Frame Number (SFN), which is a frame-unit index serving as a timing reference.

[0088] - SS / PBCH Block (Synchronization Signal / PBCH Block or SSB): An SS / PBCH block consists of N OFDM symbols and is formed by a combination of PSS, SSS, PBCH, etc. In systems where beam sweeping technology is applied, the SS / PBCH block is the minimum unit to which beam sweeping is applied. In a 5G system, N can be 4. A base station can transmit up to L SS / PBCH blocks, and the L SS / PBCH blocks are mapped within a half frame (0.5ms). The L SS / PBCH blocks are repeated periodically in units of a predetermined period P. The base station can notify the terminal of the period P through signaling. If there is no separate signaling for the period P, the terminal applies a pre-agreed default value.

[0089] FIG. 2 illustrates an example in which beam sweeping is applied in units of SS / PBCH blocks over time. Referring to FIG. 2, at time t1 (201), terminal 1 (205) receives an SS / PBCH block using a beam radiated in the direction of #d0 (203) by beamforming applied to SS / PBCH block #0. Then, at time t2 (202), terminal 2 (206) receives an SS / PBCH block using a beam radiated in the direction of #d4 (204) by beamforming applied to SS / PBCH block #4. The terminal can obtain an optimal synchronization signal through a beam radiated from the base station in the direction where the terminal is located. For example, it may be difficult for terminal 1 (205) to obtain time / frequency synchronization and essential system information from an SS / PBCH block through a beam radiated in the direction of #d4, which is far from the location of terminal 1.

[0090] In addition to the initial connection procedure described above, the terminal may also receive SS / PBCH blocks to determine whether the radio link quality of the current cell is maintained above a certain level. Furthermore, during the handover procedure in which the terminal moves the connection from the current cell to an adjacent cell, the terminal may receive SS / PBCH blocks of the adjacent cell to determine the radio link quality of the adjacent cell and to obtain time / frequency synchronization with the adjacent cell.

[0091] After the terminal obtains MIB and system information from the base station through the initial access procedure, the terminal may perform a random access procedure to transition the link with the base station to a connected state (connected state or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal transitions to the connected state, enabling one-to-one communication between the base station and the terminal. The random access procedure will be explained in detail below with reference to FIG. 3.

[0092] FIG. 3 is a diagram illustrating a random access procedure according to one embodiment of the present disclosure. FIG. 3 illustrates an example of a random access procedure, but the present disclosure is not limited thereto. Furthermore, the present disclosure is not limited to the 4-step random access procedure exemplified in FIG. 3 and may also be applied to a 2-step random access procedure (transmission and reception of message A (a message containing information corresponding to message 1 and message 3) and transmission and reception of message B (a message containing information corresponding to message 2 and message 4)).

[0093] Referring to FIG. 3, as a first step (310) of the random access procedure, the terminal transmits a random access preamble to the base station. The random access preamble, which is the initial transmission message of the terminal in the random access procedure, may be referred to as message 1. The base station can measure the transmission delay value between the terminal and the base station from the random access preamble and synchronize the uplink. At this time, the terminal may arbitrarily select which random access preamble to use from a set of random access preambles given in advance by system information. The initial transmission power of the random access preamble may be determined according to the path loss between the base station and the terminal measured by the terminal. Additionally, the terminal may determine the transmission beam direction of the random access preamble from the synchronization signal received from the base station and transmit the random access preamble.

[0094] In the second step (320), the base station transmits an uplink transmission timing control command to the terminal based on the transmission delay value measured from the random access preamble received in the first step (310). Additionally, the base station may transmit uplink resource and power control commands to be used by the terminal as scheduling information. The scheduling information may include control information for the terminal's uplink transmission beam.

[0095] If the terminal does not receive a Random Access Response (RAR) (or message 2), which is scheduling information for message 3, from the base station within a predetermined time during the second step (320), the first step (310) may be performed again. If the first step (310) is performed again, the terminal can increase the probability of the base station receiving the Random Access Preamble by increasing the transmission power of the Random Access Preamble by a predetermined step (power ramping).

[0096] In the third step (330), the terminal transmits uplink data (message 3) including its terminal ID to the base station via the uplink data channel (Physical Uplink Shared Channel, PUSCH) using the uplink resources allocated in the second step (320). The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station in the second step (320). The transmission power of the uplink data channel for transmitting Message 3 may be determined by considering the power control command received from the base station in the second step (320) and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may refer to the first uplink data signal transmitted by the terminal to the base station after the terminal transmits the random access preamble.

[0097] In step 4 (340), if the base station determines that the terminal has performed random access without collision with other terminals, it transmits data (message 4) containing the ID of the terminal that transmitted uplink data in step 3 (330) to the terminal. When the terminal receives the signal transmitted by the base station in step 4 (340), it can determine that the random access was successful. Then, the terminal can transmit HARQ-ACK information indicating successful reception of message 4 to the base station through the Physical Uplink Control Channel (PUCCH).

[0098] If the data transmitted by the terminal in the third step (330) collides with the data of another terminal and the base station fails to receive the data signal from the terminal, the base station may not transmit any further data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in the fourth step (340) within a certain period of time, it is determined that the random access procedure has failed, and the process may restart from the first step (310).

[0099] Upon successful completion of the random access procedure, the terminal transitions to a connected state, enabling one-to-one communication between the base station and the terminal. The base station receives UE capability information from the connected terminal and can adjust scheduling by referring to that information. Through the UE capability information, the terminal can inform the base station of whether it supports certain functions, the maximum allowable value of the functions supported by the terminal, etc. Therefore, the UE capability information reported by each terminal to the base station may be different for each terminal.

[0100] For example, the terminal may report UE capability information to the base station as the above UE capability information, including at least a portion of the following control information.

[0101] - Control information related to frequency bands supported by the terminal

[0102] - Control information related to channel bandwidth supported by the terminal

[0103] - Control information regarding the maximum modulation scheme supported by the terminal

[0104] - Control information regarding the maximum number of beams supported by the terminal

[0105] - Control information regarding the maximum number of layers supported by the terminal

[0106] - Control information related to CSI reporting supported by the terminal

[0107] - Control information on whether the terminal supports frequency hopping

[0108] - Bandwidth-related control information when Carrier Aggregation (CA) is supported

[0109] - Control information on whether cross-carrier scheduling is supported when carrier bundling is supported

[0110] FIG. 4 is a diagram illustrating a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure.

[0111] Referring to FIG. 4, in step 410, the base station (402) can send a UE capability information request message to the terminal (401). In response to the base station's UE capability information request, the terminal sends UE capability information to the base station in step 420.

[0112] Through the above process, a terminal connected to the base station is classified as an RRC_CONNECTED terminal, and the connected terminal can engage in one-to-one communication. Conversely, a terminal that is not connected is in the RRC_IDLE state, and the operations of terminals in these states are classified as follows.

[0113] - Operates terminal-specific DRX (Discontinuous Reception) cycles set by the upper layer

[0114] - Operation of receiving paging messages from the core network

[0115] - Obtain system information

[0116] - Measurement operation and cell reselection related to neighboring cells

[0117] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed for the initial access of terminals. In addition to the operations performed by RRC_IDLE terminals, RRC_INACTIVE terminals perform the following operations.

[0118] - Stores AS (Access stratum) information required for cell access

[0119] - Terminal-specific DRX cycle operation set by the RRC layer

[0120] - Configure RNA (RAN-based notification area) that can be utilized during handover by the RRC layer and perform periodic updates

[0121] - Monitoring RAN-based paging messages transmitted via I-RNTI

[0122] The following describes a scheduling method in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data.

[0123] Downlink Control Information (DCI) is control information transmitted by a base station to a terminal via the downlink, and may include downlink data scheduling information or uplink data scheduling information for a specific terminal. Generally, the base station can channel-code the DCI independently for each terminal and then transmit it to each terminal via the Physical Downlink Control Channel (PDCCH), which is the downlink physical control channel.

[0124] A base station may operate by applying a predetermined DCI format to a terminal to be scheduled, depending on the purpose, such as whether it is scheduling information for downlink data (downlink assignment), whether it is scheduling information for uplink data (uplink grant), or whether it is a DCI for power control.

[0125] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), which is a physical channel for downlink data transmission. Scheduling information, such as specific mapping locations in the time and frequency domains of the PDSCH, modulation schemes, HARQ-related control information, and power control information, can be provided by the base station to the terminal through the DCI related to downlink data scheduling information among the DCIs transmitted via the PDSCH.

[0126] The terminal can transmit uplink data to the base station via the PUSCH (Physical Uplink Shared Channel), which is a physical channel for uplink data transmission. Scheduling information, such as specific mapping locations in the time and frequency domains of the PUSCH, modulation schemes, HARQ-related control information, and power control information, can be provided by the base station to the terminal through the DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0127] FIG. 5 is a diagram showing a Control Resource Set (CORESET) as a time-frequency resource to which a PDCCH is mapped according to one embodiment of the present disclosure.

[0128] Referring to FIG. 5, two control resource sets (control resource set #1 (501), control resource set #2 (502)) can be set within the terminal bandwidth part (UE bandwidth part) (510) on the frequency axis and one slot (520) on the time axis. The control resource sets (501, 502) can be set to a specific frequency resource (503) within the entire terminal bandwidth part (510) on the frequency axis. On the time axis, they can be set to one or more OFDM symbols, which can be defined as the control resource set duration (504).

[0129] Control resource set #1 (501) can be set to a control resource set length of 2 symbols, and control resource set #2 (502) can be set to a control resource set length of 1 symbol.

[0130] A base station may configure one or more CORESETs for a terminal through upper-layer signaling (e.g., System Information, Master Information Block (MIB), Radio Resource Control (RRC) signaling). Configuring a CORESET for a terminal may mean providing information such as the CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information provided by the base station to the terminal to configure a CORESET may include at least some of the information included in [Table 4].

[0131] [Table 4]

[0132]

[0133] CORESET in the frequency domain It can be composed of RBs, and in the time domain It can be composed of symbols. An NR PDCCH can be composed of one or more CCEs (Control Channel Elements). One CCE can be composed of six REGs (Resource Element Groups), and a REG can be defined as one RB during one OFDM symbol. Within a CORESET, REGs can be indexed in time-first order starting with REG index 0, beginning with the first OFDM symbol of the CORESET, the lowest RB.

[0134] Interleaved and non-interleaved methods may be supported as transmission methods for PDCCH. The base station may configure the terminal to perform interleaved or non-interleaved transmission for each CORESET through upper-layer signaling. Interleaving may be performed on a REG bundle basis. A REG bundle can be defined as a set of one or more REGs. Based on the interleaved or non-interleaved transmission configuration received from the base station, the terminal may determine the CCE-to-REG mapping method in the corresponding CORESET in the manner shown in [Table 5] below.

[0135] [Table 5]

[0136]

[0137] The base station can inform the terminal of configuration information, such as which symbol the PDCCH is mapped to within the slot and the transmission period, through signaling.

[0138] FIG. 6 is a diagram showing the mapping of DCI and DMRS in REG, which is the basic unit of a downlink control channel according to one embodiment of the present disclosure.

[0139] According to FIG. 6, the basic unit of time and frequency resources constituting a control channel can be called a REG (Resource Element Group, 603), and the REG (603) can be defined as 1 OFDM symbol (601) on the time axis and 1 PRB (Physical Resource Block, 602) on the frequency axis, i.e., 12 subcarriers. A base station can concatenate REGs (603) to form a downlink control channel allocation unit.

[0140] As illustrated in FIG. 6, if the basic unit to which a downlink control channel is allocated in 5G is called a CCE (Control Channel Element, 604), then 1 CCE (604) can be composed of multiple REGs (603). For example, if the REG (603) illustrated in FIG. 6 is described, the REG (603) can be composed of 12 REs, and if 1 CCE (604) is composed of 6 REGs (603), then 1 CCE (604) can be composed of 72 REs. When a downlink control area is established, the area can be composed of multiple CCEs (604), and a specific downlink control channel can be mapped to one or multiple CCEs (604) and transmitted according to the Aggregation Level (AL) within the control area. The CCEs (604) in the control area are distinguished by numbers, and the numbers of the CCEs (604) can be assigned according to a logical mapping method.

[0141] The basic unit of the downlink control channel shown in FIG. 6, namely the REG (603), may include both the REs to which the DCI is mapped and the DMRS (605), which is a reference signal for decoding the REs, to which the DMRS is mapped. As shown in FIG. 6, three DMRSs (605) may be transmitted within one REG (603).

[0142] The search space of a PDCCH is described below. The number of CCEs required to transmit a PDCCH can be 1, 2, 4, 8, or 16 depending on the Aggregation Level (AL), and different numbers of CCEs can be used for link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel can be transmitted through L CCEs. The terminal performs blind decoding to detect signals without knowing information about the downlink control channel; to this end, a search space representing a set of CCEs can be defined. The search space is a set of downlink control channel candidates consisting of CCEs that the terminal must attempt to decode at a given aggregation level. Since there are various aggregation levels that form a group of 1, 2, 4, 8, or 16 CCEs, the terminal may have multiple search spaces. A Search Space Set can be defined as a set of search spaces at all established aggregation levels.

[0143] Search spaces can be classified into Common Search Spaces (CSS) and UE-specific Search Spaces (USS). A certain group of terminals or all terminals may examine the Common Search Space of a PDCCH to receive cell-common control information, such as dynamic scheduling or paging messages for System Information Blocks (SIBs). For example, a terminal may receive scheduling allocation information for a PDSCH for receiving system information by examining the Common Search Space of the PDCCH. In the case of the Common Search Space, since a certain group of terminals or all terminals must receive the PDCCH, it may be defined as a pre-agreed set of CCEs. Scheduling allocation information for a UE-specific PDSCH or PUSCH may be received by a terminal by examining the UE-specific Search Space of the PDCCH. The UE-specific Search Space may be defined specifically as a function of the terminal's ID (Identity) and various system parameters.

[0144] The base station can configure configuration information for the search space of the PDCCH to the terminal through upper-layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can configure the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the occasion for monitoring in slot-symbol units for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the search space, and the CORESET index to be monitored for the search space to the terminal. For example, parameters for the search space of the PDCCH may include information such as [Table 6] below.

[0145] [Table 6]

[0146]

[0147]

[0148]

[0149] Depending on the configuration information, the base station may set one or more sets of search spaces for the terminal. According to some embodiments, the base station may set search space set 1 and search space set 2 for the terminal. In search space set 1, the terminal may be configured to monitor DCI format A scrambled with X-RNTI in a common search space, and in search space set 2, the terminal may be configured to monitor DCI format B scrambled with Y-RNTI in a terminal-specific search space.

[0150] According to the configuration information, one or more sets of search spaces may exist in a common search space or a terminal-specific search space. For example, Search Space Set #1 and Search Space Set #2 may be configured as a common search space, and Search Space Set #3 and Search Space Set #4 may be configured as a terminal-specific search space.

[0151] In the common search space, terminals can monitor the following combinations of DCI formats and RNTI. Of course, they are not limited to the following examples.

[0152] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0153] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0154] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0155] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0156] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0157] - DCI format 2_4 with CRC scrambled by CI-RNTI

[0158] - DCI format 2_5 with CRC scrambled by AI-RNTI

[0159] - DCI format 2_6 with CRC scrambled by PS-RNTI

[0160] - DCI format 2_7 with CRC scrambled by PEI-RNTI

[0161]

[0162] Terminal—In a specific search space, the terminal can monitor the following combinations of DCI formats and RNTI. Of course, it is not limited to the following examples.

[0163] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0164] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0165] The above RNTIs may follow the following definitions and uses.

[0166] C-RNTI (Cell RNTI): Used for terminal-specific PDSCH or PUSCH scheduling

[0167] TC-RNTI (Temporary Cell RNTI): Used for terminal-specific PDSCH scheduling

[0168] CS-RNTI (Configured Scheduling RNTI): Used for semi-statically configured terminal-specific PDSCH scheduling.

[0169] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase

[0170] P-RNTI (Paging RNTI): Used for PDSCH scheduling where paging is transmitted.

[0171] SI-RNTI (System Information RNTI): Used for PDSCH scheduling where system information is transmitted.

[0172] INT-RNTI (Interruption RNTI): Used to indicate whether PDSCH is pucturing.

[0173] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to instruct power control commands to the PUSCH

[0174] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to instruct power control commands to the PUCCH

[0175] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to instruct power regulation commands to the SRS

[0176] The DCI formats described above may follow the definitions in [Table 7] below.

[0177] [Table 7]

[0178]

[0179] In CORESET p and search space set s, the search space of aggregate level L can be expressed as follows:

[0180] [Mathematical Formula 1]

[0181]

[0182] - L: Lamination Level

[0183] - : Carrier Index

[0184] - : Total number of CCEs existing within control domain p

[0185] - : Slot Index

[0186] - : Number of PDCCH candidates at assembly level L

[0187] - = 0, … , -1: PDCCH candidate index of aggregation level L

[0188] - i = 0, … , L -1

[0189] - , , , , ,

[0190] - : Terminal identifier

[0191] The value may be 0 for the common search space.

[0192] In the case of a terminal-specific search space, the value may correspond to a value that changes according to the terminal's identity (C-RNTI or ID set by the base station for the terminal) and the time index.

[0193] In the following, we will specifically explain how to set the TCI state for the PDCCH (or PDCCH DMRS) in a 5G communication system.

[0194] The base station can set and indicate the TCI state for the PDCCH (or PDCCH DMRS) through appropriate signaling. According to the above description, the base station can set and indicate the TCI state for the PDCCH (or PDCCH DMRS) through appropriate signaling. The above TCI state is intended to announce the Quasi-Co-location (QCL) relationship between the PDCCH (or PDCCH DMRS) and other RS ​​or channels. When a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are said to be QCLed with each other, it means that the terminal is allowed to apply some or all of the large-scale channel parameters estimated from the antenna port A to the channel measurement from the antenna port B. QCL may require associating different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) RRM (radio resource management) affected by average gain, and 4) BM (beam management) affected by spatial parameters. Accordingly, NR supports four types of QCL relationships as shown in Table 8 below.

[0195] [Table 8]

[0196]

[0197] The above spatial RX parameter may collectively refer to some or all of various parameters, such as Angle of arrival (AoA), Power Angular Spectrum (PAS) of AoA, Angle of departure (AoD), PAS of AoD, transmit / receive channel correlation, transmit / receive beamforming, and spatial channel correlation.

[0198] The above QCL relationship can be configured for the terminal through the RRC parameters TCI-State and QCL-Info as shown in Table 9 below. Referring to Table 9, the base station can configure one or more TCI states for the terminal and provide up to two QCL relationships (qcl-Type1, qcl-Type2) for the RS that references the ID of the said TCI state, i.e., the target RS. At this time, each QCL information (QCL-Info) included in each said TCI state includes the serving cell index and BWP index of the reference RS pointed to by the corresponding QCL information, the type and ID of the reference RS, and the QCL type as shown in Table 8 above.

[0199] [Table 9]

[0200]

[0201] FIG. 7 is a diagram showing base station beam allocation according to TCI state setting according to one embodiment of the present disclosure.

[0202] Referring to FIG. 7, the base station can transmit information about N different beams to the terminal through N different TCI states. For example, when N=3, the base station can notify that antenna ports referencing the different TCI states 700, 705, or 710 are associated with different spatial Rx parameters, i.e., different beams, by setting the qcl-Type2 parameters included in the three TCI states (700, 705, 710) to be associated with CSI-RS or SSB corresponding to different beams and set to QCL type D.

[0203] Specifically, the TCI state combinations applicable to the PDCCH DMRS antenna port are as shown in Table 10 below. The fourth row of Table 10 represents the combinations assumed by the terminal prior to RRC setup, and setup after RRC is not possible.

[0204] [Table 10]

[0205]

[0206] NR supports a hierarchical signaling method as shown in Fig. 8 for dynamic allocation of PDCCH beams.

[0207] FIG. 8 is a diagram illustrating a hierarchical signaling method for dynamic allocation of a PDCCH beam of NR according to one embodiment of the present disclosure.

[0208] Referring to FIG. 8, the base station can set N TCI states (805, 810, 815, ..., 820) to the terminal through RRC signaling (800), and some of these can be set as TCI states for CORESET (825). Subsequently, the base station can instruct the terminal to one of the TCI states for CORESET (830, 835, ..., 840) through MAC CE signaling (845). Subsequently, the terminal receives a PDCCH based on beam information contained in the TCI state indicated by the MAC CE signaling.

[0209] FIG. 9 is a diagram showing a TCI indication MAC CE signaling structure for a PDCCH DMRS according to one embodiment of the present disclosure.

[0210] Referring to FIG. 9, the TCI indication MAC CE signaling for the PDCCH DMRS consists of 2 bytes (16 bits) and includes a 1-bit reserved bit (910), a 5-bit serving cell ID (915), a 2-bit BWP ID (920), a 2-bit CORESET ID (925), and a 6-bit TCI state ID (930).

[0211] A base station may indicate one of the TCI state lists included in the CORESET configuration through MAC CE signaling. Until another TCI state is indicated to the CORESET through another MAC CE signaling, the terminal considers that the same QCL information applies to all one or more search spaces connected to the CORESET.

[0212] The PDCCH beam allocation method described above has the disadvantage that it is difficult to instruct a beam change faster than the MAC CE signaling delay, and that the same beam is applied uniformly to all CORESETs regardless of search space characteristics, thereby making flexible PDCCH beam operation difficult. The embodiments of the present disclosure below provide a more flexible method for setting and operating PDCCH beams. In describing the embodiments of the present disclosure below, several distinct examples are provided for convenience of explanation, but these are not mutually exclusive and can be appropriately combined and applied depending on the situation.

[0213] The base station may set one or more TCI states for a specific control resource set for the terminal, and may activate one of the set TCI states through a MAC CE activation command. For example, if {TCI state#0, TCI state#1, TCI state#2} are set as TCI states for control resource set #1, the base station may transmit a command to the terminal via MAC CE to activate TCI state#0 as the TCI state for control resource set #1. Based on the activation command for the TCI state received via MAC CE, the terminal can correctly receive the DMRS of the corresponding control resource set based on the QCL information within the activated TCI state.

[0214] For a control resource set (control resource set #0) with an index set to 0, if the terminal has not received a MAC CE activation command for the TCI state of control resource set #0, it can be assumed that the terminal has QCL with the SS / PBCH block identified in the initial access process or the non-contention-based random access process that was not triggered by the PDCCH command for the DMRS transmitted from control resource set #0.

[0215] For a control resource set (control resource set #X) with an index set to a value other than 0, if the terminal has not received a TCI state for control resource set #X, or has received one or more TCI states but has not received a MAC CE activation command to activate one of them, it can be assumed that the terminal has QCL with the SS / PBCH block identified during the initial connection process for the DMRS transmitted from control resource set #X.

[0216] Next, Downlink Control Information (DCI) in 5G systems will be explained in detail.

[0217] In a 5G system, scheduling information for uplink data (or Physical Uplink Shared Channel (PUSCH)) or downlink data (or Physical Downlink Shared Channel (PDSCH)) can be transmitted from a base station to a terminal via DCI. The terminal can monitor the fallback DCI format and the non-fallback DCI format for PUSCH or PDSCH. The fallback DCI format may consist of fixed fields selected between the base station and the terminal, and the non-fallback DCI format may include configurable fields.

[0218] DCI can be transmitted via the Physical Downlink Control Channel (PDCCH) after undergoing channel coding and modulation processes. A Cyclic Redundancy Check (CRC) is attached to the DCI message payload, and the CRC can be scrambled into a Radio Network Temporary Identifier (RNTI) corresponding to the terminal's identity. Different RNTIs may be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, or random access responses. In other words, the RNTI is not transmitted explicitly but is included in the CRC calculation process. Upon receiving a DCI message transmitted over the PDCCH, the terminal checks the CRC using the assigned RNTI; if the CRC check result is correct, the terminal knows that the message was transmitted to it.

[0219] For example, a DCI scheduling a PDSCH for System Information (SI) can be scrambled to SI-RNTI. A DCI scheduling a PDSCH for Random Access Response (RAR) messages can be scrambled to RA-RNTI. A DCI scheduling a PDSCH for Paging messages can be scrambled to P-RNTI. A DCI notifying a Slot Format Indicator (SFI) can be scrambled to SFI-RNTI. A DCI notifying Transmit Power Control (TPC) can be scrambled to TPC-RNTI. A DCI scheduling a terminal-specific PDSCH or PUSCH can be scrambled to C-RNTI (Cell RNTI).

[0220] DCI format 0_0 can be used as a countermeasure DCI for scheduling PUSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 0_0 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 11.

[0221] - Identifier for DCI formats - 1 bit- The value of this bit field is always set to 0, indicating an UL DCI format- Frequency domain resource assignment- bits where is defined in subclause 7.3.1.0- For PUSCH hopping with resource allocation type 1:- MSB bits are used to indicate the frequency offset according to Subclause 6.3 of [6, TS 38.214], where if the higher layer parameterfrequencyHoppingOffsetListscontains two offset values ​​and if the higher layer parameterfrequencyHoppingOffsetListscontains four offset values- bits provides the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214]- For non-PUSCH hopping with resource allocation type 1:- bits provides the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214]- Time domain resource assignment - 4 bits as defined in Subclause 6.1.2.1 of [6, TS 38.214]- Frequency hopping flag - 1 bit according to Table 7.3.1.1.1-3, as defined in Subclause 6.3 of [6, TS 38.214]- Modulation and coding scheme - 5 bits as defined in Subclause 6.1.4.1 of [6, TS 38.214]- New data indicator - 1 bit- Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2- HARQ process number - 4 bits- TPC command for scheduled PUSCH - 2 bits as defined in Subclause 7.1.1 of [5, TS 38.213]- Padding bits, if required.- UL / SUL indicator - 1 bit for UEs configured withsupplementaryUplinkinServingCellConfigin the cell as defined in Table 7.3.1.1.1-1 and the number of bits for DCI format 1_0 before padding is larger than the number of bits for DCI format 0_0 before padding; 0 bit otherwise.The UL / SUL indicator, if present, locates in the last bit position of DCI format 0_0, after the padding bit(s).- If the UL / SUL indicator is present in DCI format 0_0 and the higher layer parameterpusch-Configis not configured on both UL and SUL the UE ignores the UL / SUL indicator field in DCI format 0_0, and the corresponding PUSCH scheduled by the DCI format 0_0 is for the UL or SUL for which high layer parameterpucch-Configis configured;- If the UL / SUL indicator is not present in DCI format 0_0 andpucch-Configis configured, the corresponding PUSCH scheduled by the DCI format 0_0 is for the UL or SUL for which high layer parameterpucch-Configis configured.- If the UL / SUL indicator is not present in DCI format 0_0 andpucch-Configis not configured, the corresponding PUSCH scheduled by the DCI format 0_0 is for theuplink on which the latest PRACH is transmitted.

[0222] DCI format 0_1 ​​can be used as a non-defense DCI for scheduling PUSCH, whereby the CRC can be scrambled with C-RNTI. DCI format 0_1 ​​with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 12.

[0223]

[0224] DCI format 1_0 can be used as a countermeasure DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_0 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 13.

[0225]

[0226] DCI format 1_1 can be used as a non-defense DCI for scheduling PDSCH, whereby the CRC can be scrambled with C-RNTI. DCI format 1_1 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 14.

[0227]

[0228] The following describes the time domain resource allocation method for data channels in a 5G communication system.

[0229] The base station may set a table for time-domain resource allocation information for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH) for the terminal using upper-layer signaling (e.g., RRC signaling). For PDSCH, a table consisting of a maximum of maxNrofDL-Allocations = 16 entries may be set, and for PUSCH, a table consisting of a maximum of maxNrofUL-Allocations = 16 entries may be set. For example, time domain resource allocation information may include PDCCH-to-PDSCH slot timing (corresponding to a slot-unit time interval between the time when the PDCCH is received and the time when the PDSCH scheduled by the received PDCCH is transmitted, denoted as K0) or PDCCH-to-PUSCH slot timing (corresponding to a slot-unit time interval between the time when the PDCCH is received and the time when the PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), information on the position and length of the start symbol for which the PDSCH or PUSCH is scheduled within the slot, and the mapping type of the PDSCH or PUSCH. For example, information such as that shown in Tables 15 and 16 below may be notified from the base station to the terminal.

[0230] [Table 15]

[0231]

[0232] [Table 16]

[0233]

[0234] The base station may notify the terminal of one of the entries in the table for the time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., by indicating the 'time domain resource allocation' field within the DCI). The terminal may obtain time domain resource allocation information for PDSCH or PUSCH based on the DCI received from the base station.

[0235] The following describes the frequency domain resource allocation method for data channels in a 5G communication system.

[0236] In 5G, two types, resource allocation type 0 and resource allocation type 1, are supported as a method of indicating frequency domain resource allocation information for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH).

[0237] Resource allocation type 0

[0238] RB allocation information may be notified from the base station to the terminal in the form of a bitmap for the RBG (Resource Block Group). In this case, the RBG may be composed of a set of consecutive VRBs (Virtual RBs), and the size P of the RBG may be determined based on the value set by the upper layer parameter (rbg-Size) and the size value of the bandwidth part defined in Table 17 below.

[0239] [Table 17]

[0240]

[0241] - Size Total number of RGBs in bandwidth part i ( ) can be defined as follows.

[0242]

[0243] - Each bit of a bitmap of bit size can correspond to a respective RGB. The RGBs can be indexed in increasing order of frequency, starting from the lowest frequency position in the bandwidth part. Within the bandwidth part For the RBGs, from RBG#0 to RBG#( ) can be mapped from the MSB to the LSB of the RGB bitmap. The terminal can determine that the RGB corresponding to the bit value is assigned when the specific bit value in the bitmap is 1, and can determine that the RGB corresponding to the bit value is not assigned when the specific bit value in the bitmap is 0.

[0244] Resource Allocation Type 1

[0245] - RB allocation information can be notified from the base station to the terminal as information regarding the starting position and length of consecutively allocated VRBs. In this case, interleaving or non-interleaving may be additionally applied to the consecutively allocated VRBs. The resource allocation field of Resource Allocation Type 1 may be composed of a Resource Indication Value (RIV), and the RIV is the starting point of the VRB ( ) and the length of consecutively allocated RB ( It can be composed of. More specifically, The RIV within the bandwidth part of the size can be defined as follows.

[0246]

[0247] A base station may semi-statically configure time and frequency transmission resources and various transmit / receive parameters for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH) for the purpose of supporting unauthorized-based transmission and reception for the terminal.

[0248] To explain in more detail, it is as follows.

[0249] For the purpose of supporting Downlink (DL) Semi-Persistent Scheduling (SPS) to the terminal, the base station may set the following information as shown in Table 18 using upper layer signaling (e.g., RRC signaling).

[0250] [Table 18]

[0251]

[0252] DL SPS can be set in a primary cell or a secondary cell, and within a cell group, DL SPS can be set in a single cell.

[0253] In 5G, two types of non-authorization-based transmission methods (named Configured Grant, Grant free, etc.) for the uplink data channel (PUSCH) can be supported (Type-1 PUSCH transmission with a configured grant, Type-2 PUSCH transmission with a configured grant).

[0254] Non-acknowledgment-based PUSCH transmission type-1

[0255] In unauthorized-based PUSCH transmission type-1, the base station may configure specific time / frequency resources that allow unauthorized-based PUSCH transmission to the terminal using upper-layer signaling, such as RRC signaling. For example, time-axis allocation information, frequency-axis allocation information, and period information for resources that allow unauthorized-based PUSCH transmission may be configured. Additionally, the base station may configure various parameters for PUSCH transmission to the terminal using upper-layer signaling (e.g., frequency hopping, DMRS settings, MCS table, MCS, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), etc.). More specifically, the configuration information in Table 19 below may be included.

[0256] [Table 19]

[0257]

[0258]

[0259]

[0260]

[0261] When the terminal receives configuration information for unauthorized-based PUSCH transmission type-1 from the base station, the terminal may transmit PUSCH without authorization from the base station using a periodically configured resource (600). Various parameters required to transmit PUSCH (e.g., frequency hopping, DMRS configuration, MCS, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), number of precoding and layers, antenna port, frequency hopping offset, etc.) may all follow the configuration values ​​notified by the base station.

[0262] Non-acknowledgment-based PUSCH transmission type-2

[0263] In unauthorized-based PUSCH transmission type-2, the base station may set some of the information regarding specific time / frequency resources that allow unauthorized-based PUSCH transmission to the terminal (e.g., period information, etc.) as upper-layer signaling (e.g., RRC signaling). Additionally, the base station may set various parameters for PUSCH transmission to the terminal (e.g., frequency hopping, DMRS settings, MCS table, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), etc.) as upper-layer signaling. More specifically, the base station may set the configuration information in Table 20 below to the terminal as upper-layer signaling.

[0264] [Table 20]

[0265]

[0266]

[0267]

[0268] The base station may transmit a DCI composed of specific DCI field values ​​to the terminal for the purpose of activating or releasing scheduling for DL ​​SPS and UL grant Type 2.

[0269] To explain in more detail, it is as follows.

[0270] The base station can configure CS-RNTI (Configured Scheduling-RNTI) for the terminal, and the terminal can monitor a DCI format in which the CRC is scrambled with CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 21 below, the terminal may regard the DCI as a command to enable transmission and reception for DL ​​SPS or UL grant Type 2.

[0271] [Table 21]

[0272]

[0273] The base station can configure CS-RNTI (Configured Scheduling-RNTI) for the terminal, and the terminal can monitor a DCI format in which the CRC is scrambled with CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 22 below, the terminal may regard the DCI as a command to release transmission and reception for DL ​​SPS or UL grant Type 2.

[0274] [Table 22]

[0275]

[0276] The DCI instructing the release for the above DL SPS or UL grant Type 2 follows a DCI format corresponding to DCI format 0_0 or DCI format 1_0, and since DCI format 0_0 or 1_0 does not include a Carrier Indicator Field (CIF), the terminal must always monitor the PDCCH in the cell where the corresponding DL SPS or UL grant Type 2 is set in order to receive a release command for the DL SPS or UL grant Type 2 for a specific cell. Even if a specific cell is set to cross-carrier scheduling, the terminal must always monitor DCI format 1_0 or DCI format 0_0 in that cell to receive a release command for the DL SPS or UL grant Type 2 set in that cell.

[0277] In the following, we will specifically explain the carrier aggregation and scheduling methods in 5G communication systems.

[0278] A terminal can receive multiple cells (Cell or CC (Component Carrier)) from a base station and can receive a setting regarding whether cross-carrier scheduling is enabled for the cells configured in the terminal. If cross-carrier scheduling is enabled for a specific cell (Cell A, Scheduled Cell), PDCCH monitoring for Cell A is not performed at Cell A but can be performed at another cell (Cell B, Scheduling Cell) designated for cross-carrier scheduling. In this case, the Scheduled Cell (Cell A) and the Scheduling Cell (Cell B) can be configured with different numerologies. Here, the numerology may include subcarrier spacing, cyclic prefix, etc. When the numerologies of cell A and cell B are different, when cell B's PDCCH schedules cell A's PDSCH, a minimum scheduling offset as follows may be additionally considered between PDCCH and PDSCH.

[0279] Cross-Carrier Scheduling Method

[0280] ◆ Subcarrier spacing of Cell B ( ) is the subcarrier spacing of cell A ( If it is less than ), the PDSCH can be scheduled starting from the next PDSCH slot corresponding to X symbols after the last symbol of the PDCCH received from Cell B. Here, X is It may vary depending on, When X=4 symbols, When X=4 symbols, When that, X can be defined as a symbol of 8.

[0281] ◆ Subcarrier spacing of Cell B ( ) is the subcarrier spacing of cell A ( If it is greater than ), the PDSCH can be scheduled starting from a point X symbols after the last symbol of the PDCCH received by Cell B. Here, X is It may vary depending on, When X=4 symbols, When X=8 symbols, When X=12, it can be defined as a symbol.

[0282] In the following, the rate matching operation and puncturing operation will be described in detail.

[0283] When a time and frequency resource A intended to transmit an arbitrary symbol sequence A overlaps with an arbitrary time and frequency resource B, rate matching or puncturing operations may be considered as transmission and reception operations of channel A, taking into account the area resource C where resource A and resource B overlap. Specific operations may follow the details below.

[0284] Rate Matching Operation

[0285] - A base station may transmit a symbol sequence A to a terminal by mapping Channel A only to the remaining resource area, excluding Resource C which corresponds to the area overlapping with Resource B, from the entire Resource A. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol 4}, Resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and Resource B is {Resource #3, Resource #5}, the base station may sequentially map and send symbol sequence A to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3} which corresponds to Resource C within Resource A. Consequently, the base station may transmit the symbol sequence {Symbol #1, Symbol #2, Symbol #3} by mapping it to {Resource #1, Resource #2, Resource #4}, respectively.

[0286] The terminal can determine Resource A and Resource B from scheduling information regarding Symbol Sequence A from the base station, and thereby determine Resource C, which is the area where Resource A and Resource B overlap. The terminal can receive Symbol Sequence A by assuming that Symbol Sequence A was transmitted by mapping it to the remaining area of ​​Resource A, excluding Resource C. For example, if Symbol Sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol 4}, Resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and Resource B is {Resource #3, Resource #5}, the terminal can receive Symbol Sequence A by assuming that it was sequentially mapped to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3}, which corresponds to Resource C. Consequently, the terminal can perform a series of subsequent reception operations by assuming that Symbol Sequence {Symbol #1, Symbol #2, Symbol #3} was transmitted by mapping it to {Resource #1, Resource #2, Resource #4}, respectively.

[0287] Puncturing action

[0288] If there is a resource C corresponding to an area overlapping with resource B among all resources A to which the base station intends to transmit symbol sequence A to a terminal, the base station maps symbol sequence A to the entire resource A, but does not perform transmission in the resource area corresponding to resource C, and can perform transmission only in the remaining resource area of ​​resource A excluding resource C. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol #4}, resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and resource B is {Resource #3, Resource #5}, the base station can map symbol sequence A {Symbol #1, Symbol #2, Symbol #3, Symbol #4} to resource A {Resource #1, Resource #2, Resource #3, Resource #4} respectively, and can transmit only the symbol sequence {Symbol #1, Symbol #2, Symbol #4} corresponding to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3} corresponding to resource C, and may not transmit {Symbol #3} mapped to {Resource #3} corresponding to resource C. Consequently, the base station can map and transmit the symbol sequence {Symbol #1, Symbol #2, Symbol #4} to {Resource #1, Resource #2, Resource #4} respectively.

[0289] The terminal can determine resources A and B from scheduling information for symbol sequence A from the base station, and thereby determine resource C, which is the area where resources A and B overlap. The terminal can receive symbol sequence A by assuming that symbol sequence A is mapped to the entire resource A, but is transmitted only in the remaining area of ​​resource A excluding resource C. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol #4}, resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and resource B is {Resource #3, Resource #5}, the terminal can assume that symbol sequence A {Symbol #1, Symbol #2, Symbol #3, Symbol #4} is mapped to resource A {Resource #1, Resource #2, Resource #3, Resource #4} respectively, but {Symbol #3} mapped to {Resource #3} corresponding to resource C is not transmitted, and can receive by assuming that symbol sequence {Symbol #1, Symbol #2, Symbol #4} corresponding to the remaining resources {Resource #1, Resource #2, Resource #4}—excluding {Resource #3} corresponding to resource C—is mapped and transmitted. Consequently, the terminal can perform a subsequent series of receiving operations by assuming that the symbol sequence {Symbol #1, Symbol #2, Symbol #4} is transmitted and mapped to {Resource #1, Resource #2, Resource #4}, respectively.

[0290] FIG. 10 is a diagram illustrating a method for transmitting and receiving data by a base station and a terminal in consideration of a downlink data channel and rate matching resources according to one embodiment of the present disclosure.

[0291] Referring to FIG. 10, a downlink data channel (PDSCH, 1001) and a rate matching resource (1002) are illustrated. A base station may set one or more rate matching resources (1002) to a terminal through upper layer signaling (e.g., RRC signaling). The rate matching resource (1002) setting information may include time-axis resource allocation information (1003), frequency-axis resource allocation information (1004), and period information (1005). In the following, the bitmap corresponding to the frequency-axis resource allocation information (1004) is named the "first bitmap," the bitmap corresponding to the time-axis resource allocation information (1003) is named the "second bitmap," and the bitmap corresponding to the period information (1005) is named the "third bitmap." If all or part of the time and frequency resources of a scheduled data channel (1001) overlap with a set rate matching resource (1002), the base station can transmit the data channel (1001) by rate matching it in the rate matching resource (1002) portion, and the terminal can perform reception and decoding after assuming that the data channel (1001) is rate matched in the rate matching resource (1002) portion.

[0292] The base station can dynamically notify the terminal via DCI whether to rate match a data channel in the above-mentioned rate matching resource portion through additional settings (corresponding to the "rate matching indicator" within the aforementioned DCI format). Specifically, the base station can select some of the above-mentioned rate matching resources and group them into rate matching resource groups, and can indicate to the terminal via DCI using a bitmap method whether to rate match a data channel for each rate matching resource group. For example, if four rate matching resources, RMR#1, RMR#2, RMR#3, and RMR#4, are set, the base station can set RMG#1={RMR#1, RMR#2} and RMG#2={RMR#3, RMR#4} as rate matching groups, and can indicate to the terminal via a bitmap whether to rate match in RMG#1 and RMG#2, respectively, using 2 bits within the DCI field. For example, the base station can instruct the terminal to "1" if rate matching is required, and "0" if rate matching is not required.

[0293] In 5G, the granularity of "RB symbol level" and "RE level" is supported by setting the aforementioned rate matching resources to the terminal. More specifically, the following setting method may be followed.

[0294] RB symbol level

[0295] The terminal can receive up to four RateMatchPatterns as upper layer signaling for each bandwidth part, and one RateMatchPattern may include the following contents.

[0296] - As a Reserved Resource within the Bandwidth Part, a resource may be included in which the time and frequency resource domains of the said Reserve Resource are set as a combination of an RB level bitmap and a symbol level bitmap along the frequency axis. The said Reserve Resource may span across one or two slots. A time domain pattern (periodicityAndPattern) in which the time and frequency domains composed of each RB level and symbol level bitmap pair are repeated may be additionally set.

[0297] - It may include time and frequency domain resource areas set as control resource sets within the bandwidth part, and resource areas corresponding to time domain patterns set as search space settings where the resource areas are repeated.

[0298] RE level

[0299] The terminal can receive the following settings through upper-layer signaling.

[0300] - Configuration information for an RE corresponding to an LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern (lte-CRS-ToMatchAround) may include the number of ports of the LTE CRS (nrofCRS-Ports) and the LTE-CRS-vshift(s) value (v-shift), the location information of the LTE carrier's center subcarrier (carrierFreqDL) from a reference frequency point (e.g., reference point A), the LTE carrier's bandwidth size (carrierBandwidthDL) information, and subframe configuration information corresponding to a Multiast-broadcast single-frequency network (mbsfn-SubframConfigList). Based on the aforementioned information, the terminal can determine the location of the CRS within an NR slot corresponding to an LTE subframe.

[0301] - It may include configuration information for resource sets corresponding to one or more ZP (Zero Power) CSI-RS within the bandwidth part.

[0302] The following describes in detail the method for measuring and reporting channel status in a 5G communication system.

[0303] Channel state information (CSI) may include channel quality information (CQI), precoding matrix index (PMI), CSI-RS resource indicator (CRI), SS / PBCH block resource indicator (SSSBRI), layer indicator (LI), rank indicator (RI), and / or L1-RSRP (Reference Signal Received Power). The base station may control time and frequency resources for the aforementioned CSI measurement and reporting of the terminal.

[0304] For the aforementioned CSI measurement and reporting, the terminal can receive setting information for N (≥1) CSI reports (CSI-ReportConfig), setting information for M (≥1) RS transmission resources (CSI-ResourceConfig), and one or two trigger state lists (CSI-AperiodicTriggerStateList, CSI-SemiPersistentOnPUSCH-TriggerStateList) through upper layer signaling.

[0305] The setting information for the aforementioned CSI measurement and reporting may be more specifically as described in Tables 23 to 29 below.

[0306] The IE CSI-ReportConfig is used to configure a periodic or semi-persistent report sent on PUCCH on the cell in which the CSI-ReportConfig is included, or to configure a semi-persistent or aperiodic report sent on PUSCH triggered by DCI received on the cell in which the CSI-ReportConfig is included (in this case, the cell on which the report is sent is determined by the received DCI). See TS 38.214

[0019] , clause 5.2.1.CSI-ReportConfig information element-- ASN1START-- TAG-CSI-REPORTCONFIG-STARTCSI-ReportConfig ::= SEQUENCE {reportConfigId CSI-ReportConfigId,carrier ServCellIndex OPTIONAL, -- Need SresourcesForChannelMeasurement CSI-ResourceConfigId,csi-IM-ResourcesForInterference CSI-ResourceConfigId OPTIONAL, -- Need Rnzp-CSI-RS-ResourcesForInterference CSI-ResourceConfigId OPTIONAL, -- Need RreportConfigType CHOICE {periodic SEQUENCE {reportSlotConfig CSI-ReportPeriodicityAndOffset,pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource},semiPersistentOnPUCCH SEQUENCE {reportSlotConfig CSI-ReportPeriodicityAndOffset,pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource},semiPersistentOnPUSCH SEQUENCE {reportSlotConfig ENUMERATED {sl5, sl10, sl20, sl40, sl80, sl160, sl320},reportSlotOffsetList SEQUENCE (SIZE (1.. maxNrofUL-Allocations)) OF INTEGER(0..32),p0alpha P0-PUSCH-AlphaSetId},aperiodic SEQUENCE {reportSlotOffsetList SEQUENCE (SIZE (1..maxNrofUL-Allocations)) OF INTEGER(0..32)}},reportQuantity CHOICE {none NULL,cri-RI-PMI-CQI NULL,cri-RI-i1 NULL,cri-RI-i1-CQI SEQUENCE {pdsch-BundleSizeForCSI ENUMERATED {n2, n4} OPTIONAL -- Need S},cri-RI-CQI NULL,cri-RSRP NULL,ssb-Index-RSRP NULL,cri-RI-LI-PMI-CQI NULL},reportFreqConfiguration SEQUENCE {cqi-FormatIndicator ENUMERATED { widebandCQI, subbandCQI} OPTIONAL, -- Need Rpmi-FormatIndicator ENUMERATED { widebandPMI, subbandPMI} OPTIONAL, -- Need Rcsi-ReportingBand CHOICE {subbands3 BIT STRING(SIZE(3)),subbands4 BIT STRING(SIZE(4)),subbands5 BIT STRING(SIZE(5)),subbands6 BIT STRING(SIZE(6)),subbands7 BIT STRING(SIZE(7)),subbands8 BIT STRING(SIZE(8)),subbands9 BIT STRING(SIZE(9)),subbands10 BIT STRING(SIZE(10)),subbands11 BIT STRING(SIZE(11)),subbands12 BIT STRING(SIZE(12)),subbands13 BIT STRING(SIZE(13)),subbands14 BIT STRING(SIZE(14)),subbands15 BIT STRING(SIZE(15)),subbands16 BIT STRING(SIZE(16)),subbands17 BIT STRING(SIZE(17)),subbands18 BIT STRING(SIZE(18)),...,subbands19-v1530 BIT STRING(SIZE(19))} OPTIONAL -- Need S} OPTIONAL, -- Need RtimeRestrictionForChannelMeasurements ENUMERATED {configured, notConfigured},timeRestrictionForInterferenceMeasurements ENUMERATED {configured, notConfigured},codebookConfig CodebookConfig OPTIONAL, -- Need Rdummy ENUMERATED {n1, n2} OPTIONAL, -- Need RgroupBasedBeamReporting CHOICE {enabled NULL,disabled SEQUENCE {nrofReportedRS ENUMERATED {n1, n2, n3, n4} OPTIONAL -- Need S}},cqi-Table ENUMERATED {table1, table2, table3, spare1} OPTIONAL, -- Need RsubbandSize ENUMERATED {value1, value2},non-PMI-PortIndication SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerConfig)) OF PortIndexFor8Ranks OPTIONAL, -- Need R...,[[semiPersistentOnPUSCH-v1530 SEQUENCE {reportSlotConfig-v1530 ENUMERATED {sl4, sl8, sl16}} OPTIONAL -- Need R]]}CSI-ReportPeriodicityAndOffset ::= CHOICE {slots4 INTEGER(0..3),slots5 INTEGER(0..4),slots8 INTEGER(0..7),slots10 INTEGER(0..9),slots16 INTEGER(0..15),slots20 INTEGER(0..19),slots40 INTEGER(0..39),slots80 INTEGER(0..79),slots160 INTEGER(0..159),slots320 INTEGER(0..319)}PUCCH-CSI-Resource ::= SEQUENCE {uplinkBandwidthPartId BWP-Id,pucch-Resource PUCCH-ResourceId}PortIndexFor8Ranks ::= CHOICE {portIndex8 SEQUENCE{rank1-8 PortIndex8 OPTIONAL, -- Need Rrank2-8 SEQUENCE(SIZE(2)) OF PortIndex8 OPTIONAL, -- Need Rrank3-8 SEQUENCE(SIZE(3)) OF PortIndex8 OPTIONAL, -- Need Rrank4-8 SEQUENCE(SIZE(4)) OF PortIndex8 OPTIONAL, -- Need Rrank5-8 SEQUENCE(SIZE(5)) OF PortIndex8 OPTIONAL, -- Need Rrank6-8 SEQUENCE(SIZE(6)) OF PortIndex8 OPTIONAL, -- Need Rrank7-8 SEQUENCE(SIZE(7)) OF PortIndex8 OPTIONAL, -- Need Rrank8-8 SEQUENCE(SIZE(8)) OF PortIndex8 OPTIONAL -- Need R},portIndex4 SEQUENCE{rank1-4 PortIndex4 OPTIONAL, -- Need Rrank2-4 SEQUENCE(SIZE(2)) OF PortIndex4 OPTIONAL, -- Need Rrank3-4 SEQUENCE(SIZE(3)) OF PortIndex4 OPTIONAL, -- Need Rrank4-4 SEQUENCE(SIZE(4)) OF PortIndex4 OPTIONAL -- Need R},portIndex2 SEQUENCE{rank1-2 PortIndex2 OPTIONAL, -- Need Rrank2-2 SEQUENCE(SIZE(2)) OF PortIndex2 OPTIONAL -- Need R},portIndex1 NULL}PortIndex8::= INTEGER (0..7)PortIndex4::= INTEGER (0..3)PortIndex2::= INTEGER (0..1)-- TAG-CSI-REPORTCONFIG-STOP-- ASN1STOP.

[0307]

[0308]

[0309] The IE CSI-ResourceConfig defines a group of one or more NZP-CSI-RS-ResourceSet, CSI-IM-ResourceSet and / or CSI-SSB-ResourceSet.CSI-ResourceConfig information element-- ASN1START-- TAG-CSI-RESOURCECONFIG-STARTCSI-ResourceConfig ::= SEQUENCE {csi-ResourceConfigId CSI-ResourceConfigId,csi-RS-ResourceSetList CHOICE {nzp-CSI-RS-SSB SEQUENCE {nzp-CSI-RS-ResourceSetList SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourceSetsPerConfig)) OF NZP-CSI-RS-ResourceSetIdOPTIONAL, -- Need Rcsi-SSB-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-SSB-ResourceSetsPerConfig)) OF CSI-SSB-ResourceSetIdOPTIONAL -- Need R},csi-IM-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-IM-ResourceSetsPerConfig)) OF CSI-IM-ResourceSetId},bwp-Id BWP-Id,resourceType ENUMERATED { aperiodic, semiPersistent, periodic},...}-- TAG-CSI-RESOURCECONFIG-STOP-- ASN1STOP

[0310]

[0311] The IE NZP-CSI-RS-ResourceSet is a set of Non-Zero-Power (NZP) CSI-RS resources (their IDs) and set-specific parameters.NZP-CSI-RS-ResourceSet information element-- ASN1START-- TAG-NZP-CSI-RS-RESOURCESET-STARTNZP-CSI-RS-ResourceSet ::= SEQUENCE {nzp-CSI-ResourceSetId NZP-CSI-RS-ResourceSetId,nzp-CSI-RS-Resources SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerSet)) OF NZP-CSI-RS-ResourceId,repetition ENUMERATED { on, off} OPTIONAL, -- Need SaperiodicTriggeringOffset INTEGER(0..6) OPTIONAL, -- Need Strs-Info ENUMERATED {true} OPTIONAL, -- Need R...}-- TAG-NZP-CSI-RS-RESOURCESET-STOP-- ASN1STOP

[0312]

[0313] The IE CSI-SSB-ResourceSet is used to configure one SS / PBCH block resource set which refers to SS / PBCH as indicated in ServingCellConfigCommon.CSI-SSB-ResourceSet information element-- ASN1START-- TAG-CSI-SSB-RESOURCESET-STARTCSI-SSB-ResourceSet ::= SEQUENCE {csi-SSB-ResourceSetId CSI-SSB-ResourceSetId,csi-SSB-ResourceList SEQUENCE (SIZE(1..maxNrofCSI-SSB-ResourcePerSet)) OF SSB-Index,...}-- TAG-CSI-SSB-RESOURCESET-STOP-- ASN1STOP

[0314] The IE CSI-IM-ResourceSet is used to configure a set of one or more CSI Interference Management (IM) resources (their IDs) and set-specific parameters.CSI-IM-ResourceSet information element-- ASN1START-- TAG-CSI-IM-RESOURCESET-STARTCSI-IM-ResourceSet ::= SEQUENCE {csi-IM-ResourceSetId CSI-IM-ResourceSetId,csi-IM-Resources SEQUENCE (SIZE(1..maxNrofCSI-IM-ResourcesPerSet)) OF CSI-IM-ResourceId,...}-- TAG-CSI-IM-RESOURCESET-STOP-- ASN1STOP

[0315]

[0316] The CSI-AperiodicTriggerStateList IE is used to configure the UE with a list of aperiodic trigger states. Each codepoint of the DCI field "CSI request" is associated with one trigger state. Upon reception of the value associated with a trigger state, the UE will perform measurement of CSI-RS (reference signals) and aperiodic reporting on L1 according to all entries in the associatedReportConfigInfoList for that trigger state.CSI-AperiodicTriggerStateList information element-- ASN1START-- TAG-CSI-APERIODICTRIGGERSTATELIST-STARTCSI-AperiodicTriggerStateList ::= SEQUENCE (SIZE (1..maxNrOfCSI-AperiodicTriggers)) OF CSI-AperiodicTriggerStateCSI-AperiodicTriggerState ::= SEQUENCE {associatedReportConfigInfoList SEQUENCE (SIZE(1..maxNrofReportConfigPerAperiodicTrigger)) OF CSI-AssociatedReportConfigInfo,...}CSI-AssociatedReportConfigInfo ::= SEQUENCE {reportConfigId CSI-ReportConfigId,resourcesForChannel CHOICE {nzp-CSI-RS SEQUENCE {resourceSet INTEGER (1..maxNrofNZP-CSI-RS-ResourceSetsPerConfig),qcl-info SEQUENCE (SIZE(1..maxNrofAP-CSI-RS-ResourcesPerSet)) OF TCI-StateId OPTIONAL -- Cond Aperiodic},csi-SSB-ResourceSet INTEGER (1..maxNrofCSI-SSB-ResourceSetsPerConfig)},csi-IM-ResourcesForInterference INTEGER(1..maxNrofCSI-IM-ResourceSetsPerConfig) OPTIONAL, -- Cond CSI-IM-ForInterferencenzp-CSI-RS-ResourcesForInterference INTEGER (1..maxNrofNZP-CSI-RS-ResourceSetsPerConfig) OPTIONAL, -- Cond NZP-CSI-RS-ForInterference...}-- TAG-CSI-APERIODICTRIGGERSTATELIST-STOP-- ASN1STOP.

[0317]

[0318]

[0319] The CSI-SemiPersistentOnPUSCH-TriggerStateList IE is used to configure the UE with list of trigger states for semi-persistent reporting of channel state information on L1. See also TS 38.214

[0019] , clause 5.2.CSI-SemiPersistentOnPUSCH-TriggerStateList information element-- ASN1START-- TAG-CSI-SEMIPERSISTENTONPUSCHTRIGGERSTATELIST-STARTCSI-SemiPersistentOnPUSCH-TriggerStateList ::= SEQUENCE(SIZE (1..maxNrOfSemiPersistentPUSCH-Triggers)) OF CSI-SemiPersistentOnPUSCH-TriggerStateCSI-SemiPersistentOnPUSCH-TriggerState ::= SEQUENCE {associatedReportConfigInfo CSI-ReportConfigId,...}-- TAG-CSI-SEMIPERSISTENTONPUSCHTRIGGERSTATELIST-STOP-- ASN1STOP

[0320] Regarding the aforementioned CSI report settings (CSI-ReportConfig), each report setting CSI-ReportConfig can be associated with a single downlink (DL) bandwidth portion identified by the upper-layer parameter bandwidth portion identifier (bwp-id) given by the CSI-ResourceConfig, which is associated with the corresponding report setting. As for the time domain reporting operation for each report setting CSI-ReportConfig, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, and these can be configured from the base station to the terminal by the reportConfigType parameter set from the upper layer. The semi-persistent CSI reporting methods support 'PUCCH-based semi-persistent (semi-PersistentOnPUCCH)' and 'PUSCH-based semi-persistent (semi-PersistentOnPUSCH)'. In the case of a periodic or semi-permanent CSI reporting method, the terminal may receive a PUCCH or PUSCH resource to transmit the CSI from the base station via upper layer signaling. The period and slot offset of the PUCCH or PUSCH resource to transmit the CSI may be given as the numerology of the uplink (UL) bandwidth portion configured for transmitting the CSI report. In the case of a non-periodic CSI reporting method, the terminal may receive a PUSCH resource to transmit the CSI scheduled from the base station via L1 signaling (the aforementioned DCI format 0_1).

[0321] For the aforementioned CSI resource setting (CSI-ResourceConfig), each CSI resource setting CSI-ReportConfig may include S (≥1) CSI resource sets (given by the upper-level parameter csi-RS-ResourceSetList). The CSI resource set list may consist of non-zero power (NZP) CSI-RS resource sets and SS / PBCH block sets, or may consist of CSI-interference measurement (CSI-IM) resource sets. Each CSI resource setting may be located in a downlink (DL) bandwidth portion identified by the upper-level parameter bwp-id, and the CSI resource setting may be linked to a CSI report setting in the same downlink bandwidth portion. The time domain operation of the CSI-RS resources within the CSI resource setting may be set to one of 'non-periodic', 'periodic', or 'semi-permanent' by the upper-level parameter resourceType. For periodic or semi-permanent CSI resource settings, the number of CSI-RS resource sets may be limited to S=1, and the set period and slot offset may be given by the numerology of the downlink bandwidth portion identified by bwp-id. The terminal may receive one or more CSI resource settings for channel or interference measurement from the base station via upper layer signaling, and may include, for example, the following CSI resources.

[0322] - CSI-IM resources for interference measurement

[0323] - NZP CSI-RS resources for interference measurement

[0324] - NZP CSI-RS resources for channel measurement

[0325] For CSI-RS resource sets associated with a resource setting where the upper-level parameter resourceType is set to 'Aperiodic', 'Periodic', or 'Semi-permanent', the Trigger State for a CSI reporting setting where reportType is set to 'Aperiodic' and the resource setting for channel or interference measurements for one or more component cells (CC) can be set as the upper-level parameter CSI-AperiodicTriggerStateList.

[0326] Non-periodic CSI reporting of the terminal can be performed using PUSCH, periodic CSI reporting can be performed using PUCCH, and semi-permanent CSI reporting can be performed using PUSCH when triggered or activated by DCI, and using PUCCH after being activated by the MAC control element (MAC CE). As described above, CSI resource settings can also be configured as non-periodic, periodic, or semi-permanent. Combinations between CSI reporting settings and CSI resource settings can be supported based on Table 30 below.

[0327] [Table 30]

[0328]

[0329] Non-periodic CSI reporting can be triggered by the "CSI request" field of the aforementioned DCI format 0_1, which corresponds to the scheduling DCI for PUSCH. The terminal can monitor PDCCH, obtain DCI format 0_1, and obtain scheduling information and CSI request indicators for PUSCH. The CSI request indicator is N TSIt can be set to bits (=0, 1, 2, 3, 4, 5, or 6) and can be determined by the upper layer signaling (reportTriggerSize). One trigger state among one or more non-periodic CSI report trigger states that can be set by the upper layer signaling (CSI-AperiodicTriggerStateList) can be triggered by the CSI request indicator.

[0330] - If all bits of the CSI request field are 0, this may mean that a CSI report is not requested.

[0331] - If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is greater than 2NTs-1, then M CSI trigger states can be mapped to 2NTs-1 according to the selected mapping relationship, and one of the trigger states of 2NTs-1 can be indicated as a CSI request field.

[0332] - If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is less than or equal to 2NTs-1, one of the M CSI trigger states may be indicated as a CSI request field.

[0333] Table 31 below shows an example of the relationship between CSI request indicators and CSI trigger states that can be indicated by those indicators.

[0334] [Table 31]

[0335]

[0336] For a CSI resource within a CSI trigger state triggered by a CSI request field, the terminal can perform a measurement and generate a CSI therefrom (including at least one of the aforementioned CQI, PMI, CRI, SSBRI, LI, RI, or L1-RSRP, etc.). The terminal can transmit the acquired CSI using a PUSCH scheduled by the corresponding DCI format 0_1. When the 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "1", the terminal can multiplex the uplink data (UL-SCH) and the acquired CSI and transmit them to the PUSCH resource scheduled by DCI format 0_1. When the 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "0", the terminal can transmit by mapping only the CSI without the uplink data (UL-SCH) to the PUSCH resource scheduled by DCI format 0_1.

[0337] FIG. 11 is a diagram illustrating a non-periodic CSI reporting method when the CSI-RS offset is 0 according to one embodiment of the present disclosure.

[0338] Referring to FIG. 11, the terminal can monitor PDCCH (1101) to obtain DCI format 0_1, from which it can obtain scheduling information and CSI request information for PUSCH (1105). The terminal can obtain resource information for CSI-RS (1102) to be measured from the received CSI request indicator. The terminal can determine at what point in time to perform a measurement on the CSI-RS (1102) resource being transmitted based on the time when the DCI format 0_1 ​​is received and the parameter for the offset within the CSI resource set setting (e.g., the aperiodicTriggeringOffset described above) within the NZP CSI-RS resource set setting (NZP-CSI-RS-ResourceSet). More specifically, the terminal may receive the offset value X of the parameter aperiodicTriggeringOffset within the NZP-CSI-RS resource set setting as an upper layer signaling from the base station, and the set offset value X may represent the offset between the slot in which the DCI triggering the aperiodic CSI report is received and the slot in which the CSI-RS resource is transmitted. For example, the aperiodicTriggeringOffset parameter value and the offset value X may have a mapping relationship as described in Table 32 below.

[0339] [Table 32]

[0340]

[0341] Referring to FIG. 11, the aforementioned offset value (1103) may be set to X=0. In this case, the terminal may receive CSI-RS (1102) in a slot (corresponding to slot 0 in FIG. 11) that receives DCI format 0_1 ​​triggering a non-periodic CSI report, and may report the CSI information measured by the received CSI-RS to the base station via PUSCH (1105). The terminal may obtain scheduling information for PUSCH (1105) for CSI reporting (information corresponding to each field of the aforementioned DCI format 0_1) from DCI format 0_1. For example, the terminal may obtain information about the slot to transmit PUSCH (1105) from the aforementioned time domain resource allocation information for PUSCH (1105) in DCI format 0_1. In one example of FIG. 11, the terminal obtains a K2 value (1104) corresponding to a slot offset value for PDCCH-to-PUSCH as 3, and accordingly, at the time when PUSCH (1105) receives PDCCH (1101), it can be transmitted from slot 3 (1107), which is 3 slots away from slot 0 (1106).

[0342] FIG. 12 is a diagram illustrating a non-periodic CSI reporting method when the CSI-RS offset is 1 according to one embodiment of the present disclosure.

[0343] In one example of FIG. 12, the terminal can monitor the PDCCH (1201) to obtain DCI format 0_1, from which it can obtain scheduling information and CSI request information for PUSCH (1205). The terminal can obtain resource information for the CSI-RS (1202) to be measured from the received CSI request indicator. One example of FIG. 12 shows an example in which the offset value (1203) for the aforementioned CSI-RS is set to X=1. In this case, the terminal can receive the CSI-RS (1202) in the next slot (corresponding to slot 1 (1207) in FIG. 12) of the slot (corresponding to slot 0 (1206) in FIG. 12) that received the DCI format 0_1 ​​triggering a non-periodic CSI report, and can report the CSI information measured by the received CSI-RS to the base station via PUSCH (1205). The terminal can obtain scheduling information for PUSCH (1205) for CSI reporting from DCI format 0_1 ​​(information corresponding to each field of the aforementioned DCI format 0_1). For example, the terminal can obtain information about the slot to transmit PUSCH (1205) from the aforementioned time domain resource allocation information for PUSCH (1205) in DCI format 0_1. In an example of FIG. 12, the terminal obtains a K2 value (1204) corresponding to the slot offset value for PDCCH-to-PUSCH as 3, and accordingly, PUSCH (1205) can be transmitted at slot 3 (1208), which is 3 slots away from slot 0 (1206), at the time when PDCCH (1201) is received.

[0344] Next, we will explain in detail the Bandwidth Part (BWP) settings in the 5G communication system.

[0345] FIG. 13 is a diagram showing the settings for a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

[0346] Referring to FIG. 13, the terminal bandwidth (UE bandwidth) (1300) can be configured into two bandwidth parts, namely Bandwidth Part #1 (BWP#1) (1301) and Bandwidth Part #2 (BWP#2) (1302). The base station can configure one or more bandwidth parts for the terminal, and for each bandwidth part, the following information can be configured as shown in Table 33.

[0347] [Table 33]

[0348]

[0349] The above information can be transmitted by the base station to the terminal via upper-layer signaling, for example, Radio Resource Control (RRC) signaling. Among one or more configured bandwidth parts, at least one bandwidth part may be activated. Whether a configured bandwidth part is activated can be transmitted quasi-statically from the base station to the terminal via RRC signaling or dynamically via Downlink Control Information (DCI).

[0350] Prior to the RRC (Radio Resource Control) connection, the terminal can receive the Initial Bandwidth Part (Initial BWP) for initial connection from the base station via the MIB (Master Information Block). More specifically, during the initial connection phase, the terminal can receive configuration information regarding the Control Resource Set (CORESET) and Search Space via the MIB, through which the Physical Downlink Control Channel (PDCCH) can be transmitted to receive the system information required for initial connection (Remaining System Information; which may correspond to RMSI or System Information Block 1; SIB1). The Control Resource Set and Search Space configured via the MIB can each be regarded as Identity (ID) 0. The base station can notify the terminal via the MIB of configuration information, such as frequency allocation information, time allocation information, and numerology, for Control Resource Set #0. In addition, the base station may notify the terminal via the MIB of configuration information regarding the monitoring period and occasion for control area #0, i.e., configuration information for search area #0. The terminal may regard the frequency area set as control area #0 obtained from the MIB as an initial bandwidth part for initial access. At this time, the identifier (ID) of the initial bandwidth part may be considered as 0.

[0351] The settings for the bandwidth part supported by the above 5G can be used for various purposes.

[0352] According to one embodiment, if the bandwidth supported by the terminal is smaller than the system bandwidth, this can be supported through the bandwidth part setting. For example, by setting the frequency location of the bandwidth part (setting information 2) to the terminal, the terminal can transmit and receive data at a specific frequency location within the system bandwidth.

[0353] For the purpose of supporting different numerologies, a base station may set multiple bandwidth parts for a terminal. For example, to support data transmission and reception using both a 15 kHz subcarrier interval and a 30 kHz subcarrier interval for a terminal, two bandwidth parts may be set to subcarrier intervals of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency division multiplexed, and when data transmission and reception is to be performed with a specific subcarrier interval, the bandwidth part set to that subcarrier interval may be activated.

[0354] In addition, for the purpose of reducing the power consumption of the terminal, the base station may set bandwidth parts with different bandwidth sizes for the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and always transmits and receives data using that bandwidth, very large power consumption may occur. In particular, in a situation where there is no traffic, monitoring unnecessary downlink control channels using a large bandwidth of 100 MHz can be very inefficient in terms of power consumption. To reduce the power consumption of the terminal, the base station may set a bandwidth part with a relatively small bandwidth, such as 20 MHz, for the terminal. In a situation where there is no traffic, the terminal can perform monitoring operations in the 20 MHz bandwidth part, and when data is generated, it can transmit and receive data using the 100 MHz bandwidth part according to the instructions of the base station.

[0355] In the method for configuring the above bandwidth part, terminals prior to RRC connection (Connected) can receive configuration information for the Initial Bandwidth Part through the Master Information Block (MIB) during the initial connection phase. More specifically, the terminal can receive a Control Resource Set (CORESET) for a downlink control channel through which Downlink Control Information (DCI) scheduling System Information Blocks (SIB) can be transmitted from the MIB of the Physical Broadcast Channel (PBCH). The bandwidth of the control resource set by the MIB can be considered as the Initial Bandwidth Part, and through the configured Initial Bandwidth Part, the terminal can receive the Physical Downlink Shared Channel (PDSCH) through which SIBs are transmitted. In addition to receiving SIBs, the Initial Bandwidth Part may also be utilized for Other System Information (OSI), paging, and Random Access.

[0356] When one or more bandwidth parts are set for a terminal, the base station may instruct the terminal to change the bandwidth part using the Bandwidth Part Indicator field within the DCI. For example, referring to FIG. 13, if the currently active bandwidth part of the terminal is Bandwidth Part #1 (1301), the base station may instruct the terminal to Bandwidth Part #2 (1302) using the Bandwidth Part Indicator within the DCI, and the terminal may perform a bandwidth part change to Bandwidth Part #2 (1302) indicated by the received Bandwidth Part Indicator within the DCI.

[0357] As mentioned above, since DCI-based bandwidth part changes can be directed by a DCI that schedules a PDSCH or PUSCH (Physical Uplink Shared Channel), when a terminal receives a request to change a bandwidth part, it must be able to receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI without difficulty in the changed bandwidth part. To this end, the standard specifies requirements for the delay time (TBWP) required when changing a bandwidth part, which can be defined, for example, as shown in Table 34 below.

[0358] [Table 34]

[0359]

[0360] The requirements for bandwidth part change delay time support Type 1 or Type 2 depending on the terminal's capability. The terminal can report the supported bandwidth part delay time type to the base station.

[0361] In accordance with the requirements for the aforementioned bandwidth part change delay time, when a terminal receives a DCI containing a bandwidth part change indicator in slot n, the terminal can complete the change to the new bandwidth part indicated by the bandwidth part change indicator at a time not later than slot n + TBWP, and can perform transmission and reception for the data channel scheduled by the corresponding DCI in the changed new bandwidth part. When the base station intends to schedule a data channel to the new bandwidth part, it may determine the time domain resource allocation for the data channel by considering the terminal's bandwidth part change delay time (TBWP). That is, when the base station schedules a data channel to the new bandwidth part, in the method of determining the time domain resource allocation for the data channel, it may schedule the data channel after the bandwidth part change delay time. Accordingly, the terminal may not expect the DCI indicating the bandwidth part change to indicate a slot offset (K0 or K2) value smaller than the bandwidth part change delay time (TBWP).

[0362] If a terminal receives a DCI (e.g., DCI format 1_1 or 0_1) instructing a change in the bandwidth part, the terminal may not perform any transmission or reception during a time interval corresponding to the time interval from the third symbol of the slot in which the PDCCH containing the said DCI was received to the beginning of the slot indicated by the slot offset value (K0 or K2) indicated by the time domain resource allocation indicator field within the said DCI. For example, if a terminal receives a DCI instructing a change in the bandwidth part in slot n, and the slot offset value indicated by the said DCI is K, the terminal may not perform any transmission or reception from the third symbol of slot n to the symbol before slot n+K (i.e., the last symbol of slot n+K-1).

[0363] Next, we will explain how to set transmission and reception related parameters for each bandwidth part in 5G.

[0364] A terminal may receive one or more bandwidth parts from a base station, and may additionally receive parameters to be used for transmission and reception (e.g., uplink and downlink data channel and control channel related setting information, etc.) for each configured bandwidth part. For example, referring to FIG. 13, when a terminal receives bandwidth part #1 (1301) and bandwidth part #2 (1302), the terminal may receive transmission / reception parameter #1 for bandwidth part #1 (1301) and transmission / reception parameter #2 for bandwidth part #2 (1302). When bandwidth part #1 (1301) is activated, the terminal can perform transmission and reception with the base station based on transmission / reception parameter #1, and when bandwidth part #2 (1302) is activated, the terminal can perform transmission and reception with the base station based on transmission / reception parameter #2.

[0365] More specifically, the following parameters can be set from the base station to the terminal.

[0366] First, regarding the uplink bandwidth part, the information in Table 35 can be set.

[0367] BWP-Uplink ::= SEQUENCE {bwp-Id BWP-Id,bwp-Common BWP-UplinkCommon OPTIONAL, -- Cond SetupOtherBWPbwp-Dedicated BWP-UplinkDedicated OPTIONAL, -- Cond SetupOtherBWP...}BWP-UplinkCommon ::= SEQUENCE {genericParameters BWP,rach-ConfigCommon SetupRelease { RACH-ConfigCommon} OPTIONAL, -- Need Mpusch-ConfigCommon SetupRelease { PUSCH-ConfigCommon} OPTIONAL, -- Need Mpucch-ConfigCommon SetupRelease { PUCCH-ConfigCommon} OPTIONAL, -- Need M...}BWP-UplinkDedicated ::= SEQUENCE {pucch-Config SetupRelease { PUCCH-Config} OPTIONAL, -- Need Mpusch-Config SetupRelease { PUSCH-Config} OPTIONAL, -- Need MconfiguredGrantConfigSetupRelease { ConfiguredGrantConfig} OPTIONAL, -- Need Msrs-ConfigSetupRelease { SRS-Config} OPTIONAL, -- Need MbeamFailureRecoveryConfigSetupRelease { BeamFailureRecoveryConfig} OPTIONAL, -- Cond SpCellOnly...}

[0368] According to [Table 35], the terminal may receive cell-specific (or cell-common or common) transmission-related parameters from the base station (e.g., parameters related to Random Access Channel (RACH), Physical Uplink Control Channel (PUCCH), and Physical Uplink Shared Channel) (corresponding to BWP-UplinkCommon). Additionally, the terminal may receive terminal-specific (or dedicated) transmission-related parameters from the base station (e.g., parameters related to PUCCH, PUSCH, Configured Grant PUSCH, and Sounding Reference Signal (SRS)) (corresponding to BWP-UplinkDedicated).

[0369] Next, regarding the downlink bandwidth part, the following information can be set as shown in Table 36.

[0370] BWP-Downlink ::= SEQUENCE {bwp-Id BWP-Id,bwp-Common BWP-DownlinkCommon OPTIONAL, -- Cond SetupOtherBWPbwp-Dedicated BWP-DownlinkDedicated OPTIONAL, -- Cond SetupOtherBWP...}BWP-DownCommon ::= SEQUENCE {genericParameters BWP,pdcch-ConfigCommon SetupRelease { PDCCH-ConfigCommon} OPTIONAL, -- Need Mpdsch-ConfigCommon SetupRelease { PDSCH-ConfigCommon} OPTIONAL, -- Need M...}BWP-DownDedicated ::= SEQUENCE {pdcch-Config SetupRelease { PDCCH-Config} OPTIONAL, -- Need Mpdsch-Config SetupRelease { PDSCH-Config} OPTIONAL, -- Need Msps-ConfigSetupRelease { SPS-Config} OPTIONAL, -- Need MradioLinkMonitoringConfigSetupRelease { radioLinkMonitoringConfig} OPTIONAL, -- Cond SpCellOnly...}

[0371] According to [Table 36], the terminal may receive cell-specific (or cell-common or common) reception-related parameters from the base station (e.g., parameters related to the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel) (corresponding to BWP-DownlinkCommon). Additionally, the terminal may receive terminal-specific (or dedicated) reception-related parameters from the base station (e.g., parameters related to PDCCH, PDSCH, Semi-persistent Scheduled PDSCH, and Radio Link Monitoring (RLM)) (corresponding to BWP-UplinkDedicated).

[0372] Below, we will explain in detail the DRX (Discontinuous Reception) settings in a 5G communication system.

[0373] FIG. 14 illustrates Discontinuous Reception (DRX) in a 5G communication system according to one embodiment of the present disclosure.

[0374] DRX is an operation in which a terminal using a service receives data discontinuously while in an RRC connected state, where a wireless link is established between the base station and the terminal. When DRX is applied, the terminal can turn on the receiver at specific points to monitor the control channel, and turn off the receiver if no data is received for a certain period to reduce the terminal's power consumption. The DRX operation can be controlled by a MAC layer device based on various parameters and timers.

[0375] Referring to FIG. 14, Active time (1405) is the time during which the terminal wakes up at every DRX cycle to monitor the PDCCH. Active time (1405) can be defined as follows.

[0376] - drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer is running; or

[0377] - a Scheduling Request is sent on PUCCH and is pending; or

[0378] - a PDCCH indicating a new transmission addressed to the C-RNTI of the MAC entity has not been received after successful reception of a Random Access Response for the Random Access Preamble not selected by the MAC entity among the contention-based Random Access Preamble

[0379] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, ra-ContentionResolutionTimer, etc. are timers whose values ​​are set by the base station, and have the function of setting the terminal to monitor PDCCH when certain conditions are satisfied.

[0380] drx-onDurationTimer (1415) is a parameter for setting the minimum time the terminal stays awake in the DRX cycle. drx-InactivityTimer (1420) is a parameter for setting the additional time the terminal stays awake when receiving a PDCCH (1430) instructing a new uplink transmission or downlink transmission. drx-RetransmissionTimerDL is a parameter for setting the maximum time the terminal stays awake to receive a downlink retransmission in the downlink HARQ procedure. drx-RetransmissionTimerUL is a parameter for setting the maximum time the terminal stays awake to receive an uplink retransmission grant in the uplink HARQ procedure. drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, and drx-RetransmissionTimerUL can be set as, for example, time, number of subframes, number of slots, etc. ra-ContentionResolutionTimer is a parameter for monitoring PDCCH in a random access procedure.

[0381] The inActive time (1410) is a time during which the PDCCH is not monitored or / or the PDCCH is not received during the DRX operation, and the remaining time after subtracting the Active time (1405) from the total time of performing the DRX operation may be the inActive time (1410). If the terminal does not monitor the PDCCH during the Active time (1405), it may enter a sleep or inActive state to reduce power consumption.

[0382] The DRX cycle refers to the period during which a terminal wakes up and monitors the PDCCH. In other words, it refers to the time interval or on-duration occurrence cycle between when the terminal monitors a PDCCH and when it monitors the next PDCCH. There are two types of DRX cycles: short DRX cycle and long DRX cycle. The short DRX cycle can be applied optionally.

[0383] Long DRX cycle (1425) is the longer of the two DRX cycles set in the terminal. While operating as Long DRX, the terminal restarts drx-onDurationTimer (1415) at a point where Long DRX cycle (1425) has elapsed from the starting point (e.g., start symbol) of drx-onDurationTimer (1415). When operating as Long DRX cycle (1425), the terminal may start drx-onDurationTimer (1415) in a slot after drx-SlotOffset in a subframe satisfying [Equation 2] below. Here, drx-SlotOffset refers to the delay before starting drx-onDurationTimer (1415). drx-SlotOffset can be set, for example, as time, the number of slots, etc.

[0384] [Mathematical Formula 2]

[0385]

[0386] At this time, drx-LongCycleStartOffset may include Long DRX cycle (1525) and drx-StartOffset, and may be used to define the subframe to start Long DRX cycle (1425). For example, drx-LongCycleStartOffset may be set to time, number of subframes, number of slots, etc.

[0387] A short DRX cycle is the shorter of the two DRX cycles defined in the terminal. The terminal operates in a long DRX cycle (1425), and when a specific event occurs during the active time (1405), such as receiving a PDCCH (1430) instructing a new uplink transmission or downlink transmission, it starts or restarts the drx-InactivityTimer (1420), and if the drx-InactivityTimer (1420) expires or a DRX command MAC CE is received, it can operate in a short DRX cycle. For example, in FIG. 14, the terminal starts the drx-ShortCycleTimer at the time of the previous drx-onDurationTimer (1415) or drx-InactivityTimer (1420) expiration, and can operate in a short DRX cycle until the drx-ShortCycleTimer expires. When the terminal receives a PDCCH (1430) instructing a new uplink transmission or downlink transmission, it may extend the Active Time (1405) or delay the arrival of the InActive Time (1410) in anticipation of additional uplink transmission or downlink transmission in the future. While the terminal is operating in short DRX, it starts the drx-onDurationTimer (1415) again at a time when a short DRX cycle has elapsed from the start of the previous On duration. After that, when the drx-ShortCycleTimer expires, the terminal operates in Long DRX cycle (1425) again.

[0388] When operating in a short DRX cycle, the terminal may start drx-onDurationTimer (1415) after drx-SlotOffset in a subframe satisfying [Equation 3] below. Here, drx-SlotOffset represents a delay before starting drx-onDurationTimer (1415). For example, drx-SlotOffset can be set to time, the number of slots, etc.

[0389] [Mathematical Formula 3]

[0390]

[0391] Here, drx-ShortCycle and drx-StartOffset can be used to define the subframe to start the Short DRX cycle. drx-ShortCycle and drx-StartOffset can be set, for example, to time, number of subframes, number of slots, etc.

[0392] Up to this point, the DRX operation has been described with reference to FIG. 14. According to one embodiment, the terminal can reduce the power consumption of the terminal by performing the DRX operation. However, even if the terminal performs the DRX operation, the terminal does not always receive the PDCCH associated with the terminal during Active Time (1405). Therefore, in one embodiment of the present disclosure, a signal controlling the operation of the terminal can be provided to save the power of the terminal more efficiently.

[0393] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed for the initial access of terminals. In addition to the operations performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following processes.

[0394] - Stores AS (Access stratum) information required for cell access

[0395] - Terminal-specific DRX cycle operation set by the RRC layer

[0396] - Configure RNA (RAN (radio access network)-based notification area) that can be utilized during handover by the RRC layer and perform periodic updates.

[0397] - Monitoring RAN-based paging messages transmitted via I-RNTI (inactive-radio network temporary identifier)

[0398] A terminal in the RRC_CONNECTED state can change from the RRC_CONNECTED state to the RRC_INACTIVE or RRC_IDLE state upon receiving an RRC Release instruction from the base station.

[0399] A terminal in the RRC_INACTIVE or RRC_IDLE state can change from the RRC_INACTIVE or RRC_IDLE state to the RRC_CONNECTED state by performing random access and completing all random access procedures.

[0400] A scheduling method is described below in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data.

[0401] Downlink Control Information (DCI) may be control information transmitted by a base station to a terminal via the downlink. Downlink Control Information may include downlink data scheduling information or uplink data scheduling information for a specific terminal. Generally, the base station may perform channel coding for the DCI independently for each terminal and then transmit it to each terminal via the Physical Downlink Control Channel (PDCCH), which is a downlink physical control channel.

[0402] A base station may operate by applying a defined DCI format to a terminal for scheduling, depending on the purpose, such as whether it is scheduling information for downlink data (Downlink assignment), scheduling information for uplink data (Uplink grant), or DCI for power control.

[0403] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), which is a physical channel for transmitting downlink data. The base station can provide the terminal with scheduling information, such as specific mapping locations in the time and frequency domains of the PDSCH, modulation schemes, HARQ-related control information, and power control information, through the DCIs related to downlink data scheduling information among the DCIs transmitted via the PDSCH.

[0404] The terminal can transmit uplink data to the base station via the PUSCH (Physical Uplink Shared Channel), which is a physical channel for uplink data transmission. The base station can provide the terminal with scheduling information, such as specific mapping locations in the time and frequency domains of the PUSCH, modulation schemes, HARQ-related control information, and power control information, through the DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0405] For the RRC_IDLE / RRC_INACTIVE terminal, the aforementioned DRX operation is performed and a paging message is received. The terminal may monitor one Paging Occasion (PO) during the DRX cycle. The PO may be a set of PDCCH monitoring occasions and may include multiple time slots (or subframes, or OFDM symbols) in which paging control information can be transmitted and received. The Paging Frame (PF) may be a single radio frame (10ms) and may include one or more POs or the start point of the PO (e.g., an offset).

[0406] PF and PO can be determined by the following formulas.

[0407] The System Frame Number (SFN) for the PF can be determined by (SFN + PF_offset) mod T = (T div N) * (UE_ID mod N), where PF_offset is an offset for determining the PF, T is a DRX cycle, and N is the number of PFs per DRX cycle (e.g., cell common, cell specific), which can be determined by a higher signal such as system information, and UE_ID is a terminal ID (e.g., 5G-S-TMSI), which can be determined by the core network.

[0408] The PFs determined by N may refer to paging frames that are commonly applied to terminals within a cell, and may be referred to as cell common PFs for convenience.

[0409] i_s, which indicates the PO index, can be determined by i_s = floor (UE_ID / N) mod Ns, where Ns can represent the number of POs in a single PF and can be determined by higher signals such as system information.

[0410] For example, assuming PF_offset=3, T=128, N=T / 4=32, Ns=4, UE_ID mod 32 is 1, and floor(UE_ID / 32) mod 4 is 1, the parameter values ​​can be determined by the following formula.

[0411] (SFN + 3) mod 128 = (128 div 32)*(UE_ID mod 32) = 4*1 = 4,

[0412] i_s = floor (UE_ID / 32) mod 4 = 1

[0413] Therefore, the paging frame PF that a terminal with the above UE_ID must receive can be determined as a radio frame with SFN 1, 129, 257, ... among the cell common PFs, and the PO can be determined as the (i_s + 1)th PO among the 4 POs within the PF.

[0414] The reception of PEI (Paging Early Indication) is described in more detail below. In order to reduce terminal power consumption while monitoring and receiving the paging control channel and paging data channel in every DRX cycle, the terminal may receive PEI.

[0415] According to various embodiments of the present disclosure, a terminal may monitor or receive a PEI Occasion (PEI-O) once before receiving paging during a DRX cycle. When the terminal receives a PEI and the PEI indicates a subgroup and paging occasion to which the terminal belongs, the terminal belonging to the subgroup may monitor the associated paging occasion (PO). If the terminal does not detect the PEI in the PEI occasion, or if the PEI does not indicate a subgroup and paging occasion to which the terminal belongs, the terminal does not need to monitor the associated paging occasion (PO), thereby reducing terminal power consumption.

[0416] The terminal can determine the PEI occlusion as follows. The PEI occlusion may be located backward by a subframe offset relative to the radio frame of a reference point that is located forward by pei-FrameOffset relative to the PF containing the associated PO. The terminal can monitor the PEI at the PEI occlusion determined by the above method. Here, pei-FrameOffset, subframe offset, etc., may be determined by higher-level signals such as system information.

[0417] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The contents of the present disclosure are applicable to FDD, TDD and / or XDD (and / or SBFD, full duplex) systems. In the present disclosure, upper signaling (or upper layer signaling) is a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel, and may be referred to as RRC signaling, PDCP signaling, or a MAC (medium access control) control element (MAC control element; MAC CE).

[0418] For convenience in the following description of the present disclosure, cells, transmission points, panels, beams, and / or transmission directions that can be distinguished through upper layer / L1 parameters such as TCI state or spatial relation information, or indicators such as cell ID, TRP ID, and panel ID, may be described uniformly as TRP (transmission reception point), beam, or TCI state. Accordingly, when applying the present disclosure in practice, TRP, beam, or TCI state may be appropriately replaced with one of the above terms.

[0419] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Although embodiments of the present disclosure are described below using a 5G system as an example, embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, LTE or LTE-A mobile communication and mobile communication technologies developed after 5G may be included therein. Accordingly, embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure, as judged by a person skilled in the art. The contents of the present disclosure are applicable to FDD, TDD, XDD (or SBFD, full duplex) systems.

[0420] Furthermore, in describing the present disclosure, if it is determined that a detailed description of related functions or configurations could unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined in consideration of their functions within the present disclosure, and these definitions may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0421] In describing the present disclosure below, the term "upper layer signaling" may refer to a signaling corresponding to at least one or a combination of at least one of the following signalings.

[0422] - MIB (Master Information Block)

[0423] - SIB (System Information Block) or SIB

[0424] - RRC (Radio Resource Control)

[0425] - MAC (Medium Access Control) CE (Control Element)

[0426] In addition, L1 signaling may be a signaling corresponding to at least one or a combination of at least one of the following physical layer channels or signaling methods using signaling.

[0427] - PDCCH (Physical Downlink Control Channel)

[0428] - DCI (Downlink Control Information)

[0429] - Terminal-specific (UE-specific) DCI

[0430] - Group common DCI

[0431] - Common DCI

[0432] - Scheduling DCI (e.g., DCI used for the purpose of scheduling downlink or uplink data)

[0433] - Non-scheduling DCI (e.g., DCI not intended for scheduling downlink or uplink data)

[0434] - PUCCH (Physical Uplink Control Channel)

[0435] - UCI (Uplink Control Information)

[0436] The term "slot" used in the present disclosure below is a general term that may refer to a specific time unit corresponding to TTI (Transmit Time Interval), and specifically, it may refer to a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system.

[0437] In the present disclosure, deep sleep and ultra deep sleep may be distinguished based on which components within the cell / base station may be turned off. Taking the main radio (MR) as an example, when the main radio is completely OFF, all components within the main radio may be OFF. When the main radio is in a deep sleep state, the oscillator, RF-FE (radio frequency-front end), and baseband modem may be OFF, while the control processor and DDR (double data rate) memory may still be ON. When the main radio is in an ultra deep sleep state, the oscillator, RF-FE (radio frequency-front end), and baseband modem may be OFF, and the control processor and DDR memory may also operate at very low power or be OFF at all.

[0438] The present disclosure may be applied to RRC idle, RRC inactive, and RRC connected terminals.

[0439] In the present disclosure, the statement that a particular cell is for data communication and / or data communication only may include the particular cell performing not only data communication but also other signal transmission and reception. For example, signal transmission and reception other than sinking and / or connecting may be included in the data communication.

[0440] In the present disclosure, transitioning a cell to a specific state may include the cell maintaining a specific state without changing its state. For example, transitioning a cell to a deep sleep state or an ultra-deep sleep state may include the cell maintaining a deep sleep state or an ultra-deep sleep state.

[0441] In the following disclosure, the examples are described through a number of embodiments, but these are not independent, and one or more embodiments may be applied simultaneously or in combination.

[0442] As described above, in order to achieve ultra-high-speed data services reaching several Gbps, 5G systems support ultra-wideband signal transmission and reception or utilize spatial multiplexing methods using multiple transmitting and receiving antennas, while supporting various power saving modes to reduce the power consumption of terminals. On the other hand, excessive power consumption may also occur at base stations.

[0443] For example, the number of required power amplifiers (PAs) increases in proportion to the number of transmitting antennas equipped in a base station or terminal. The maximum output of the base station and terminal depends on the characteristics of the power amplifiers, and generally, the maximum output of a base station varies depending on the size of the cell covered by the base station. Usually, the maximum output is expressed in dBm units. The maximum output of a terminal is usually 23 dBm or 26 dBm.

[0444] As an example of a commercial 5G base station, the base station is equipped with 64 transmitting antennas and a corresponding 64 power amplifiers in the 3.5 GHz frequency band and can operate at a bandwidth of 100 MHz. Consequently, the energy consumption of the base station increases in proportion to the output of the power amplifiers and the operating time of the power amplifiers.

[0445] Compared to LTE base stations, 5G base stations have a relatively higher operating frequency band, characterized by a wide bandwidth and many transmitting antennas. While this feature has the effect of increasing data rates, it incurs costs due to the increased energy consumption of the base stations. Therefore, the more base stations that make up a mobile communication network, the greater the energy consumption of the entire mobile communication network becomes in proportion.

[0446] As mentioned above, the energy consumption of a base station depends significantly on the operation of the power amplifier. Since the power amplifier is involved in the base station's transmission operation, the base station's downlink (DL) transmission operation is highly correlated with the base station's energy consumption. The base station's uplink (UL) reception operation accounts for a relatively small proportion of the base station's energy consumption. The physical channel and physical signal transmitted by the base station over the downlink are as follows.

[0447] - PDSCH (Physical Downlink Shared Channel): A downlink data channel containing data to be transmitted to one or more terminals.

[0448] - PDCCH (Physical Downlink Control Channel): A downlink control channel containing scheduling information for PDSCH and PUSCH (Physical Uplink Control Channel). Alternatively, it may be transmitted as a PDCCH alone without the PDSCH or PUSCH to be scheduled, and control information such as slot formats and power control commands may be transmitted from the PDCCH. The scheduling information includes resource information to which the PDSCH or PUSCH is mapped, information related to HARQ (hybrid automatic repeat request), power control information, etc.

[0449] - PBCH (Physical Broadcast Channel): A downlink broadcast channel that provides the MIB (Master Information Block), which is essential system information required for the transmission and reception of the terminal's data and control channels.

[0450] - PSS (Primary Synchronization Signal): A signal that serves as the reference for DL ​​time and / or frequency (hereinafter time / frequency) synchronization and provides some information about the cell ID.

[0451] - SSS (Secondary Synchronization Signal): A signal that serves as the reference for DL ​​time / frequency synchronization and provides the cell ID and some other partial information.

[0452] - DM-RS (Demodulation Reference Signal): A reference signal for terminal channel estimation for each of PDSCH, PDCCH, and PBCH.

[0453] - CSI-RS (Channel-state Information Reference Signal): A downlink signal that serves as a reference for measuring the downlink channel state of a terminal.

[0454] - PT-RS (Phase-tracking Reference Signal): Downlink signal for phase tracking

[0455] From the perspective of base station energy conservation, stopping downlink transmission operations halts power amplifier operation, thereby enhancing energy savings. Furthermore, reducing the operation of not only the power amplifier but also other base station devices, such as baseband units, enables additional energy savings.

[0456] Similarly, even though uplink reception operations account for a relatively small portion of the base station's total energy consumption, additional energy savings can be achieved if the uplink reception operation can be stopped.

[0457] The downlink transmission operation of a base station basically depends on the amount of downlink traffic. For example, if there is no data to transmit to a terminal over the downlink, the base station does not need to transmit a PDSCH or a PDCCH to schedule the PDSCH. Alternatively, if transmission can be temporarily deferred for reasons such as the data not being sensitive to transmission delay, the base station may not transmit a PDSCH or / and a PDCCH.

[0458] In contrast, physical channels and physical signals such as PSS, SSS, PBCH, and CSI-RS are characterized by being transmitted repeatedly at a predetermined interval, regardless of data transmission to the terminal. Therefore, even if the terminal does not receive data, it can continuously update downlink time / frequency synchronization, downlink channel status, and radio link quality. In other words, the aforementioned PSS, SSS, PBCH, and CSI-RS are essential for downlink transmission regardless of downlink data traffic, thereby causing base station energy consumption. Consequently, base station energy savings can be achieved by controlling the transmission of these signals—which are unrelated to (or have low relevance to) data traffic—to occur less frequently.

[0459] Through the two base station energy saving methods mentioned above, the energy saving effect of the base station can be maximized by stopping or minimizing the operation of the base station's power amplifier and related RF devices, baseband devices, etc., during the time interval when the base station is not performing downlink transmission.

[0460] Alternatively, energy consumption of a base station can be reduced by switching off part of the base station's antenna or power amplifier. In this case, adverse effects such as reduced cell coverage or reduced throughput may occur as a counter-effect to the energy saving effect of the base station.

[0461] For example, if a base station operating in a 100 MHz bandwidth with 64 transmitting antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band as described above activates only 4 transmitting antennas and 4 power amplifiers during a specific time interval and switches the rest off to save base station energy, the base station energy consumption during that time interval will be reduced to about 1 / 16 (=4 / 64), but due to a decrease in maximum transmission power and a decrease in beamforming gain, it becomes difficult to achieve the cell coverage and throughput that would be achieved with the existing 64 antennas and power amplifiers.

[0462] The above base station energy saving methods can be further classified into three categories. These include a base station energy saving method in the frequency domain that adjusts the size of the BWP according to base station traffic, a base station energy saving method in the spatial domain that adaptively reduces the number of antenna ports, and a base station energy saving method in the time domain that adjusts the cycles of CSI-RS, SSB, and DRX. These three types of base station energy saving methods are used individually or in combination depending on base station characteristics such as base station traffic or coverage, and the corresponding change information must be shared / transmitted to the terminal.

[0463] Consequently, in situations where changed information or energy saving modes are shared with the terminal, the impact of the energy saving mode on energy-intensive technologies such as CA / DC (carrier aggregation / dual connectivity), PDSCH / PUSCH / PUCCH repetition, and mTRP (multi-TRP) must be examined.

[0464] The base station energy saving method proposed in this disclosure is described below through specific embodiments. The first to fourth embodiments described below may be implemented separately and / or at least some of the first to fourth embodiments may be implemented in combination.

[0465] <1st Embodiment>

[0466] The first embodiment relates to the structure of a network communication system for realizing energy saving.

[0467] FIG. 15 is a drawing for illustrating an existing network communication system to which an embodiment of the present disclosure is applicable.

[0468] Referring to Fig. 15, multiple cells 1, 2, 3, and 4 are shown. Since all cells must support not only terminals in a connected state (or connected terminals, RRC connected terminals) but also terminals in an idle state (or idle terminals, RRC idle terminals) (and / or RRC inactive terminals), base station energy saving must be performed in short cycles, such as light sleep or micro sleep, for periodic reference signal (e.g., SSB) transmission even when no traffic is present.

[0469] Note that although multiple cells are shown in FIG. 15, the cell may correspond to at least one of a DU (Distributed Unit), RU (Radio Unit), TRP (Transmission and Reception Point), or carrier, but is not limited thereto.

[0470] Referring to FIG. 15, an idle terminal can synchronize with a cell transmitting a sync signal, select a cell for initial access, and execute a RACH (Random Access Channel) procedure to finally connect to the cell. FIG. 15 illustrates a case where the terminal connects to Cell 1 and performs communication. In the conventional communication system of FIG. 15, considering the mobility of the idle terminal, it may be difficult to achieve network power savings because all cells are powered on for syncing / connecting with the terminal.

[0471] FIG. 16a is a drawing showing an example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0472] Referring to FIG. 16a, a plurality of cells, for example, Cell 1 and Cell 2 (Cell 2A, Cell 2B, Cell 2C), are illustrated. Unlike FIG. 15, Cell 1 is a sync / access cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be data cells that do not perform sync / access functions and only perform data communication with the terminal. Here, the cells that only perform data communication with the terminal (Cell 2A, Cell 2B, Cell 2C) are not limited to cells that only perform data communication, and may also include cells that perform functions other than sync / access functions. For example, data communication may include the transmission and reception of reference signals and / or other signals, and the cells that only perform data communication may also perform the transmission and reception of reference signals and / or other signals in addition to sync / access functions. Hereinafter, unless specifically stated otherwise, Cell 2 in the present disclosure may be understood to include one or more cells, for example, Cell 2A, Cell 2B, and Cell 2C. That is, Cell 2 in the present disclosure may be understood to be one or more cells contrasted with Cell 1.

[0473] Note that although multiple cells are shown in FIG. 16a, the cell may correspond to at least one of a DU (Distributed Unit), RU (Radio Unit), TRP (Transmission and Reception Point), or carrier, but is not limited thereto.

[0474] Referring to FIG. 16a, the idle terminal synchronizes with Cell 1, which transmits a sync signal, and performs a RACH (Random Access Channel) procedure on Cell 1 to perform initial access, thereby finally connecting to Cell 1. After initial access to Cell 1, the terminal attempts to connect to a cell (e.g., Cell 2A, Cell 2B, or Cell 2C) to transmit and receive actual data. In FIG. 16a, it is assumed that Cell 1 can control Cell 2A, Cell 2B, and Cell 2C to save network power. Accordingly, Cell 1 provides the terminal with settings for the cells controlled by Cell 1, and the terminal can receive the settings for the cells controlled by Cell 1 from Cell 1 (1601). Additionally, Cell 1 can determine the cells to control (1602) through an inter-cell interface.

[0475] Specifically, Cell 1 can control the Tx / Rx power on / off of the cell(s) it controls, e.g., Cell 2A, Cell 2B, and / or Cell 2C. Cell 1 can request the cell(s) it controls to turn on the Tx / Rx power so that the cell(s) it controls can transmit and receive data and / or signals with the terminal (1603). The cell that receives the request for Tx / Rx power on from Cell 1 can transmit and receive signals with the terminal. Cell 1 can send a request for Tx / Rx power on to one or more of the cells it controls, and the cell that receives the request can perform an action accordingly. For example, if Cell 1 requests Cell 2A to turn on the Tx / Rx power, Cell 2A can perform data communication with the terminal.

[0476] There may be various methods for turning on / off the Tx / Rx power of the cell(s) controlled by Cell 1. For example, the Tx / Rx power of the cell(s) controlled by Cell 1 can be turned on / off by utilizing the location information of the terminal. For example, based on the location information of the terminal, Cell 2A is determined as the cell for data communication with the terminal among Cell 2A to Cell 2C, and Cell 1 can request to turn on the Tx / Rx power for the determined Cell 2A. However, it should be noted that the present disclosure does not limit such methods to a specific method.

[0477] Through the method according to one embodiment of the present disclosure illustrated in FIG. 16a, Cell 2A, Cell 2B, and Cell 2C may be in a deep sleep state, and only the cell(s) that have Tx / Rx turned on at the request of Cell 1 may be powered on (On state) to transmit a signal to the terminal and / or receive a signal from the terminal.

[0478] In FIG. 16a, a reference signal is illustrated as a signal transmitted by the Tx / Rx-on cell(s); however, it should be noted that the present disclosure does not limit the signal transmitted by the Tx / Rx-on cell(s) to a specific signal. Therefore, the terminal can receive the reference signal from the Tx / Rx-on cell(s) and perform data communication. FIG. 16a illustrates a case where the terminal performs data communication with Cell 2A.

[0479] FIG. 16b is a drawing showing another example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0480] Next, referring to FIG. 16b, a plurality of cells, for example, Cell 1 and Cell 2 (Cell 2A, Cell 2B, Cell 2C), are illustrated. Unlike FIG. 16a, Cell 1 is a sync cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be access / data cells that perform initial connection and data communication with a terminal without performing the function of a sync. Although a plurality of cells are illustrated in FIG. 16b, it should be noted that the cell may correspond to at least one of a DU (Distributed Unit), RU (Radio Unit), TRP (Transmission and Reception Point), or a carrier, but is not limited thereto.

[0481] Referring to FIG. 16b, the idle terminal can synchronize with the cell transmitting the sync signal and select the cell. FIG. 16b illustrates the case where Cell 1 is selected.

[0482] In FIG. 16b, it is assumed that Cell 1 can control Cell 2 (Cell 2A, Cell 2B, Cell 2C) to save network power. Accordingly, Cell 1 provides settings for the cells controlled by Cell 1 to a terminal, and the terminal can receive settings for the cells controlled by Cell 1 from Cell 1 (1604). Additionally, Cell 1 can determine the cells to control through an inter-cell interface (1605).

[0483] Specifically, Cell 1 can control the Tx / Rx power on / off of the cell(s) it controls, e.g., Cell 2A, Cell 2B, and / or Cell 2C. Cell 1 can request the cell(s) it controls to turn on the Tx / Rx power so that the cell(s) it controls can transmit and receive data and / or signals with the terminal (1606). The cell that receives the request for Tx / Rx power on from Cell 1 can transmit and receive signals with the terminal. Cell 1 can send a request for Tx / Rx power on to one or more of the cells it controls, and the cell that receives the request can perform an action accordingly. For example, if Cell 1 requests Cell 2A to turn on the Tx / Rx power, Cell 2A can perform data communication with the terminal.

[0484] There may be various methods for turning on / off the Tx / Rx power of the cell(s) controlled by Cell 1. For example, the Tx / Rx power of the cell(s) controlled by Cell 1 can be turned on / off by utilizing the location information of the terminal. For example, based on the location information of the terminal, Cell 2A is determined as the cell for data communication with the terminal among Cell 2A to Cell 2C, and Cell 1 can request to turn on the Tx / Rx power for the determined Cell 2A. However, it should be noted that the present disclosure does not limit such methods to a specific method.

[0485] Through the method according to one embodiment of the present disclosure exemplified in FIG. 16b, Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be in a deep sleep state, and only the cell(s) that have Tx / Rx turned on at the request of Cell 1 may be powered on (On state) to transmit a signal to the terminal and / or receive a signal from the terminal. Although FIG. 16b shows a reference signal as the signal transmitted by the cell(s) that have Tx / Rx turned on, it should be noted that the present disclosure does not limit the signal transmitted by the cell(s) that have Tx / Rx turned on to a specific signal.

[0486] Unlike FIG. 16a, with reference to FIG. 16b, the terminal can perform a RACH (Random Access Channel) procedure with the cell(s) that have Tx / Rx turned on by Cell 1. For example, the terminal may have acquired at least a DL sync by including a reference signal for syncing, and / or the terminal may have at least a DL sync with Cell 2 (at least one of Cell 2A, 2B, and 2C). Accordingly, the terminal can perform a RACH procedure. FIG. 16b illustrates a case where the terminal performs a RACH procedure with Cell 2A and then connects to perform data communication.

[0487] FIG. 17a is a drawing showing an example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0488] Referring to FIG. 17a, a plurality of cells, for example, Cell 1 and Cell 2 (Cell 2A, Cell 2B, Cell 2C), are illustrated. Cell 1 is a sync / access cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be data cells that do not perform sync / access functions and only perform data communication with the terminal. Here, the cells that only perform data communication with the terminal (Cell 2A, Cell 2B, Cell 2C) are not limited to cells that only perform data communication, and may also include cells that perform functions other than sync / access functions. For example, data communication may include the transmission and reception of reference signals and / or other signals, and the cells that only perform data communication may also perform the transmission and reception of reference signals and / or other signals in addition to sync / access functions.

[0489] Compared to FIG. 16a and / or FIG. 16b, in the example of FIG. 17a, Cell 2A, Cell 2B, and Cell 2C may include a WUR (Wake-up receiver). If the cells include a WUR, Cell 2 (Cell 2A, Cell 2B, Cell 2C) can turn off the MR (Main Radio) to enter an ultra-deep sleep state, which may be more advantageous for energy saving. Although multiple cells are shown in FIG. 17a, it should be noted that the cell may correspond to at least one of a DU (Distributed Unit), RU (Radio Unit), TRP (Transmission and Reception Point), or a carrier, but is not limited thereto.

[0490] Referring to FIG. 17a, the idle terminal synchronizes with Cell 1, which transmits a sync signal, selects a cell among Cell 1, Cell 2A, Cell 2B, or Cell 2C for initial access, and executes a RACH (Random Access Channel) procedure to finally connect to the cell. In FIG. 17a, it is assumed that Cell 1 can provide information about Cell 2 (Cell 2A, Cell 2B, Cell 2C). Therefore, Cell 1 provides settings for other cells (Cell 2A, Cell 2B, Cell 2C) to the terminal, and the terminal can receive settings for the cells controlled by Cell 1 from Cell 1 (1701). Upon receiving the settings for the cells controlled by Cell 1, the terminal can transmit a WUS (Wake-up signal) to the other cells (Cell 2A, Cell 2B, Cell 2C) based on the received settings (1702). And the cells (Cell 2A, Cell 2B, Cell 2C) that were in an ultra deep sleep state will receive a WUS signal and turn on MR (On state), and then be able to transmit a signal to the terminal and / or receive a signal from the terminal.

[0491] In this case, if the MR of all cells (Cell 2A, Cell 2B, Cell 2C) is turned on, the effectiveness of network power saving may be reduced. Therefore, it is necessary to ensure that only the necessary cells are woken up through various methods. For example, a method may be considered to turn on the MR (i.e., switch the MR to the on state) only when the strength of the WUS signal received by cells (Cell 2A, Cell 2B, Cell 2C) that were in an ultra-deep sleep state is above or exceeds a predetermined threshold. Here, the strength of the WUS signal may be referred to as WUSRP (Wake-up signal received power). The threshold can be set through various methods. For example, the threshold can be set via RRC, MAC-CE, DCI, or a combination of one or more of these. Alternatively, the threshold may be set based on the inter-cell interface (and / or inter-base station interface). Alternatively, the threshold may be set from the core network. Alternatively, the threshold may have a predefined value. Alternatively, a combination of at least some of the methods for setting threshold values ​​described above may be considered. It should also be noted that the present disclosure does not limit the method for enhancing the effect of network power saving to the above method. That is, the method described above is an embodiment of the present disclosure, and the present disclosure is not limited to the embodiment described above.

[0492] In FIG. 17a, a reference signal is shown as a signal transmitted by the cell(s) with the MR turned on, but note that the present disclosure does not limit the signal to a specific signal.

[0493] FIG. 17a illustrates a case where the MR of Cell 2A, having received the WUS, is turned on to transmit a reference signal to the terminal and perform data communication. For example, the terminal can transmit the WUS to Cell 2A, Cell 2B, and Cell 2C. Among these, the MR of Cell 2A, having received a WUS signal with a strength greater than or exceeding a threshold, is turned on to transmit a reference signal to the terminal and perform data communication.

[0494] FIG. 17b is a drawing showing another example for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0495] Referring to FIG. 17b, a number of cells, for example, Cell 1 and Cell 2 (Cell 2A, Cell 2B, Cell 2C), are illustrated. Unlike FIG. 17a, Cell 1 is a sync cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be access / data cells that do not perform the function of a sync but perform initial connection and data communication with the terminal. In the example of FIG. 17b, compared to FIG. 16a and / or FIG. 16b, Cell 2 (Cell 2A, Cell 2B, Cell 2C) may include a WUR (Wake-up receiver). If the cells include a WUR, Cell 2 (Cell 2A, Cell 2B, Cell 2C) can turn off the MR (Main Radio) to enter an ultra-deep sleep state, which may be more advantageous for energy saving. Note that although multiple cells are shown in FIG. 17(b), the cell may correspond to at least one of a DU (Distributed Unit), RU (Radio Unit), TRP (Transmission and Reception Point), or carrier, but is not limited thereto.

[0496] Referring to FIG. 17b, the idle terminal can synchronize with the cell transmitting the sync signal and select the cell. FIG. 17b illustrates the case where Cell 1 is selected.

[0497] In FIG. 17b, it is assumed that Cell 1 can provide information about Cell 2 (Cell 2A, Cell 2B, Cell 2C). Thus, Cell 1 provides settings for other cells (Cell 2A, Cell 2B, Cell 2C) to the terminal, and the terminal can receive settings for the cells controlled by Cell 1 from Cell 1 (1703). Upon receiving the settings for the cells controlled by Cell 1, the terminal can transmit a WUS (Wake-up signal) to the other cells (Cell 2A, Cell 2B, Cell 2C) based on the received settings (1704). Then, the cells (Cell 2A, Cell 2B, Cell 2C) that were in an ultra deep sleep state receive the WUS signal and turn on the MR (On state), and can transmit a signal to the terminal and / or receive a signal from the terminal.

[0498] In this case, if the MR of all cells (Cell 2A, Cell 2B, Cell 2C) is turned on, the effectiveness of network power saving may be reduced. Therefore, it is necessary to ensure that only the necessary cells are woken up through various methods. For example, a method may be considered to turn on the MR only when the strength of the WUS signal received by cells (Cell 2A, Cell 2B, Cell 2C) that were in an ultra-deep sleep state is above a predetermined threshold. Here, the strength of the WUS signal may be referred to as WUSRP (Wake-up signal received power). The threshold can be set through various methods. For example, the threshold can be set through RRC, MAC-CE, DCI, or a combination of one or more of these. Alternatively, the threshold may be set based on the inter-cell interface (and / or inter-base station interface). Alternatively, the threshold may be set from the core network. Alternatively, the threshold may have a predefined value. Alternatively, a combination of at least some of the above-described methods for setting the threshold may be considered. In addition, it should be noted that the method for enhancing the effect of network power saving in the present disclosure is not limited to the above method.

[0499] In FIG. 17b, a reference signal is shown as a signal transmitted by the cell(s) with the MR turned on, but note that the present disclosure does not limit the signal to a specific signal.

[0500] Unlike FIG. 17a, with reference to FIG. 17b, the terminal can perform a RACH (Random Access Channel) procedure with access / data cell(s) (Cell 2A, Cell 2B, Cell 2C). For example, the terminal may have at least acquired a DL sync by including a reference signal for syncing, and / or the terminal may have at least one DL sync with Cell 2 (at least one of Cell 2A, 2B, and 2C). Accordingly, the terminal can perform a RACH procedure.

[0501] FIG. 17b illustrates a case where the terminal performs data communication by connecting after executing a RACH procedure with Cell 2A. For example, the terminal can transmit WUS to Cell 2A, Cell 2B, and Cell 2C. Among these, Cell 2A's MR is turned on and transmits a reference signal to the terminal upon receiving a WUS signal having a strength greater than or exceeding a threshold, and the terminal can connect to Cell 2A by executing a RACH procedure for Cell 2A. Subsequently, data communication between the terminal and Cell 2A can be performed.

[0502] For RRC_IDLE terminals, the sync cell becomes the PCell, while for RRC_CONNECTED terminals, the data cell performing data communication becomes the PCell. RRC_CONNECTED terminals may configure another data cell as the SCell if necessary, depending on the situation. Additionally, if dual connectivity is supported, another data cell or sync cell can be configured as the SCG (secondary cell group). Alternatively, the sync cell and the subsequent data cells can form the MCG (master cell group). In this case, the PCell becomes the sync cell, and the subsequent data cells can become the SCell. The SCG can be composed of another sync cell and the subsequent data cells, and the corresponding sync cell may become the PSCell (Primary SCG cell). Alternatively, all base stations belonging to the MCG or SCG may serve as data cells. The PCell may change depending on the entity checking paging, or the PCell may be configured regardless of this entity.

[0503] <2nd Example>

[0504] A second embodiment relates to a method for reducing the latency of a terminal connecting from a sync cell to a data cell in a cell structure according to an embodiment of the present disclosure described with reference to FIGS. 16a to 16b and / or FIGS. 17a to 17b.

[0505] When DL traffic is present, an idle / inactive terminal can perform a procedure to find a data cell after receiving a synchronization signal (e.g., SSB), system information (e.g., SIB X), and paging. At this time, the terminal may find the data cell by transmitting a WUS, or the sync cell may directly trigger the search. If UL traffic occurs, the terminal may perform a procedure to find the data cell without receiving paging after receiving the synchronization signal and system information. In this case, the procedure to find the data cell may vary depending on the entity searching for the data cell. For example, if the terminal transmits a WUS, the terminal can find the data cell directly. On the other hand, if the terminal does not transmit a WUS and the sync cell triggers the search, additional procedures may be required because the sync cell is unaware of whether the terminal has generated UL traffic. In this case, the terminal can first connect to the sync cell and notify the sync cell of the presence of UL traffic through a random access procedure, and the sync cell can then wake up the appropriate data cell(s) based on this information. Afterward, when the data cell search is finished, the terminal receives the SSB transmitted from the data cell, and can transition to the final connected state after undergoing a random access procedure using the RACH occasion connected to the SSB.

[0506] Assuming the above procedure, significant connection delays may occur during the process of finding the optimal data cell for the terminal. For example, to find the optimal data cell from inactive data cells, the terminal must activate the inactive data cells and receive SSBs from the activated data cells; this procedure can cause significant energy consumption.

[0507] In terms of reducing such latency, if an active data cell exists and its link performance satisfies a certain standard, it may be more advantageous in terms of throughput or energy savings to connect to and transmit / receive data through that data cell, even if it is not the optimal data cell.

[0508] In addition, until it connects to a specific data cell and switches to connected mode, the terminal must go through the process of searching for the data cell while camping in the sync cell. This is similar to the existing cell reselection process, which refers to the process of finding another serving cell to camp in when the RSRP and RSRQ for the serving cell (assuming the terminal is camping in the sync cell here) do not satisfy specific criteria. Specifically, the terminal measures Srxlev as RSRP and Squal as RSRQ for the serving cell; if these values ​​are greater than the thresholds SIntraSearchP and SIntraSearchQ, respectively, the terminal does not perform additional measurements on adjacent cells. Conversely, if they are greater than the thresholds, the terminal performs measurements on adjacent cells. Here, SIntraSearchP and SIntraSearchQ are thresholds for RSRP and RSRQ for intra-frequency measurement, and the terminal can receive information regarding SIntraSearchP and SIntraSearchQ through higher layer signaling.

[0509] For inter-frequency or inter-RAT frequencies having a reselection priority higher than the reselection priority of the current camping cell's frequency, the terminal must perform measurements of the inter-frequency or inter-RAT frequency with the higher priority.

[0510] For inter-frequency and inter-RAT frequencies with a reselection priority equal to or lower than the reselection priority of the current camping cell's frequency, and for inter-RAT frequencies with a reselection priority lower than the current camping cell's frequency, if these values ​​are greater than the thresholds SIntraSearchP and SIntraSearchQ, respectively, the terminal may choose not to perform measurements on inter-frequency cells with equal or lower priority or inter-RAT frequency cells with lower priority. However, the terminal must search the higher-priority inter-frequency hierarchy for at least every Thigher_priority_search. Conversely, the terminal must perform measurements on NR inter-frequency cells with equal or lower priority or inter-RAT frequency cells with lower priority. Here, SnonIntraSearchP and SnonIntraSearchQ are thresholds for RSRP and RSRQ for inter-frequency or inter-RAT frequency measurements based on signals received from the upper layer.

[0511] If Srxlev or Squal fails to exceed the thresholds SIntraSearchP, SIntraSearchQ or SnonIntraSearchP, SnonIntraSearchQ, respectively, the cell reselection procedure is initiated. However, if cell reselection is performed simply because the signal strength of a candidate cell measured by the terminal is high, a "ping-pong" phenomenon may occur where the camping cell is switched. To prevent this, two methods have been introduced: 1) a cell ranking method that provides a margin to the current camping cell to minimize switching; and 2) replacing the camping cell if a new cell has a better cell ranking than the existing camping cell for a certain period of time. Specifically, regarding method 1), the rankings of the camping cell and neighboring cells are R s and R n Assuming that, R s and R n Each is as follows.

[0512] R s = Q meas,s + Q hyst - Qoffset temp

[0513] R n = Q meas,n - Q offset - Qoffset temp

[0514] Here, Q meas,x is the RSRP measurement for the camping cell or neighboring cell, and Q hyst is transmitted to SIB2 as an offset for the serving cell introduced to prevent ping pong cell reselection. Qoffset is transmitted to the terminal to SIB3 as an offset for intra-frequency or inter-frequency.

[0515] Specifically, 2) in a method of replacing a camping cell when the new cell has a better cell ranking than the existing camping cell for a certain period of time, the terminal may re-select a new cell only if the following conditions are satisfied.

[0516] - Time interval T reselection During this time, based on the cell re-selection criteria specified above, the new cell ranks higher than the serving cell.

[0517] - More than 1 second has elapsed since the terminal camped in the current serving cell.

[0518] FIG. 18 is a diagram showing the procedure of a terminal camping on in a cell structure of an existing network communication system to which an embodiment of the present disclosure is applicable.

[0519] A terminal in Idle / inactive mode camps for a serving cell (1801) and can perform two main actions. Specifically, the terminal in Idle / inactive mode can perform cell reselection based on a trigger (1811) that occurs when the RSRP or RSRQ of the serving cell is lower than a specific threshold, or it can switch to connected mode (1804) when DL or UL traffic occurs. When the terminal performs cell reselection based on a trigger (1811) that occurs when the RSRP or RSRQ of the serving cell is lower than a specific threshold, if the trigger (1811) is activated, the terminal performs cell reselection to switch the current camping cell and can perform a cell ranking-based cell reselection evaluation process (1802). In this case, if a suitable cell is found (the serving cell it was camping in or a cell with a higher ranking), it is considered that a suitable cell (1812) has been found, and it can perform camping mode (1801) again in that cell. On the other hand, if a suitable cell is not found in (1802) (1813), the terminal may perform a procedure (1803) to find any other random cell (any cell) that is not based on cell ranking. When a procedure to switch to connected mode (1804) is performed because DL or UL traffic occurs, if DL or UL traffic occurs, the terminal exits the idle / inactive mode it was previously maintaining (1814) and can switch to connected mode (1804).

[0520] FIG. 18 is valid in the structure of FIG. 15 where all cells support idle / connected, but it may not be valid in a structure where the roles of idle / connected are separated into a sync cell and a data cell, as in FIG. 16a to 16b and / or FIG. 17a to 17b. In particular, although the idle / inactive terminal is camping in a sync cell, if DL or UL traffic occurs, in order to transmit and receive data for the traffic, it must find a data cell and switch to connected mode in that data cell, so there may be a difference from FIG. 18, where it switches from a camping cell to connected mode.

[0521] FIG. 19 is a diagram showing the procedure of a terminal camped on in a cell structure of a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0522] A terminal in idle / inactive mode camps for a serving cell (1901) and can perform two main operations. Specifically, the terminal in idle / inactive mode can perform cell reselection based on a trigger (1911) that occurs when the RSRP or RSRQ of the serving cell is lower than a specific threshold, or perform a procedure to switch from idle / inactive mode to another mode (1912) when DL or UL traffic occurs. When the terminal performs cell reselection based on a trigger (1911) that occurs when the RSRP or RSRQ of the serving cell is lower than a specific threshold, if the trigger (1911) is activated, the terminal performs cell reselection to switch the current camping cell and can perform a cell ranking-based cell reselection evaluation process (1902). At this time, the cells that the terminal can find in the cell reselection evaluation process (1902) are cells related to the sync cell, and frequency information or a cell list for this can be transmitted through the system information of the existing serving cell. The operation of the terminal may vary depending on whether a suitable cell is detected (1904) by the terminal that performed the cell reselection evaluation process (1902). For example, if a suitable cell is found (such as a serving cell that was being camped in or a cell with a higher ranking), it is considered that a suitable cell has been found, and the terminal may perform camping mode (1901) again in that cell. On the other hand, if the terminal does not find a suitable cell, the terminal may perform a procedure (1905) to find any cell other than the cell ranking.When DL or UL traffic occurs and a procedure to switch from idle / inactive mode to another mode (1912) is performed, the terminal may perform a cell reselection evaluation process (1902) to exit the idle / inactive mode that was previously maintained (1912). At this time, the cell reselection evaluation process (1902) performed by the terminal is a procedure to find a data cell, so it may perform a cell reselection evaluation process based on a threshold value for RSRP or RSRQ rather than a cell ranking-based cell reselection evaluation process that compares the signal strength of the sync cell and the data cell. Therefore, the terminal may determine whether it is a suitable cell based on the threshold value for RSRP or RSRQ received from the serving cell. Also, at this time, the cells that the terminal can find for the cell reselection evaluation process (1902) are cells related to the data cell, and frequency information or a cell list for the cells related to the data cell may be transmitted through the system information of the existing serving cell.Here, to reduce additional delay time, the idle / inactive terminal may store a small set of data cells by measuring the RSRP or RSRQ of available data cells within the cell list or frequency information based on system information received in advance from the serving cell prior to the cell reselection evaluation process (1902), and perform a procedure to find one data cell within that small set of data cells through the cell reselection evaluation process (1902). After performing the cell reselection evaluation process (1902), the terminal may operate depending on whether a suitable data cell has been found (1903). For example, if the terminal has found a suitable data cell, the terminal may connect to that data cell and switch to connected mode (1906). On the other hand, if the terminal has not found a suitable data cell, it may activate an inactive data cell to find a available data cell. Depending on whether the data cell supports WUR (1907), if the data cell supports WUR, the terminal may perform an operation (1908) of transmitting WUS to the data cell as in FIG. 17a and / or FIG. 17b, or, if the data cell does not support WUR, the terminal may also activate the data cell(s) after connecting to the sync cell as in FIG. 16a and / or FIG. 16b (1909). The specific operation of the terminal transmitting WUS to the data cell in step 1908 may refer to the content described above with reference to FIG. 17a and / or FIG. 17b in the first embodiment.In step 1909, the specific method for activating the data cell(s) after the terminal connects to the sync cell can be described by referring to the content described above in the first embodiment with reference to FIG. 16a and / or FIG. 16b.

[0523] <Third Embodiment>

[0524] The third embodiment is an example for reducing the delay time in the cell reselection process of the second embodiment.

[0525] Referring to FIG. 19, if the terminal lacks WUS transmission capability or the terminal is unable to transmit WUS, the idle / inactive terminal must first connect to a sync cell (1909). After connecting to the sync cell, the terminal can perform measurements from a data cell that is activated by the sync cell, and / or perform small data transmission to the sync cell if necessary. At this time, in order for the terminal to transmit and receive actual data, it must connect to the data cell, switch to connected mode, and receive an RRC configuration from the data cell. However, since the terminal has no connected data cell between connecting to the sync cell and connecting to the data cell, it cannot receive an RRC configuration from the data cell. Accordingly, the state of the terminal may be ambiguous between connecting to the sync cell and connecting to the data cell.

[0526] Figure 20 illustrates the state and state transition of a terminal of existing technology.

[0527] Referring to FIG. 20, the terminal may be in any one of three states: RRC CONNECTED (2001), RRC INACTIVE (2002), and RRC IDLE (2003). When DL or UL traffic occurs in the RRC IDLE (2003) state, a state transition for connection establishment (2012) occurs via random access, and the terminal may change to the RRC CONNECTED (2001) state. Then, when the terminal in the RRC CONNECTED (2001) state has exhausted all traffic and wishes to return to an idle state, it receives a Release message from the base station and transitions to the RRC IDLE (2003) state. The RRC INACTIVE (2002) state was introduced to reduce signal overhead and lower costs by enabling quick and efficient reconnection to the RRC connection state (UE identification information, security information, and mobile communication information are stored on both the terminal and the core network). Therefore, for terminals that continuously transition to the RRC CONNECTED (2001) state, the base station informs them through signaling to transition to the RRC INACTIVE (2002) state, and provides a state transition (2011) by connection establishment and / or connection inactivation so that they can quickly transition to RRC CONNECTED (2001) when DL or UL traffic occurs.

[0528] If there is no longer any traffic for a terminal set to the RRC INACTIVE (2002) state and a transition to the RRC CONNECTED (2001) state does not occur for a long time, the terminal may transition to the RRC IDLE (2003) state. However, a transition from the RRC IDLE (2003) state to the RRC INACTIVE (2002) state does not occur.

[0529] After the terminal connects to the sync cell and before connecting to the data cell, the terminal's state may be RRC IDLE (2003), RRC INACTIVE (2002), or a new state. First, when the terminal's state is RRC IDLE (2003), the terminal transitions to a connection mode and can perform simple data transmission and reception with the sync cell (e.g., small data transmission). However, at this point, the terminal's objective is to find the data cell, and the connection from the connected sync cell to the data cell is a handover. Therefore, in this case, overhead for the handover will inevitably occur. Additionally, there may be restrictions on actions indicated by the paging message, such as the generation of DL traffic or changes in system information. In this case, the terminal must switch to the bandwidth part where the paging is transmitted and receive the paging from the current serving cell, the sync cell. Next, when the terminal's state is RRC INACTIVE (2002), there is an advantage in that the terminal's paging monitoring, measurement, small data transmission, and mobility operations can be maintained as before. However, as mentioned in Fig. 20, since transitioning from the RRC IDLE (2003) state to the RRC INACTIVE (2002) state is not currently supported, it must be made possible to enable such state transition. In this process, the terminal can receive at least a portion of the RRC configuration for the data cell from the sync cell to enable fast and efficient connection to the RRC connection state. In this case, additionally, the remaining portion of the RRC configuration required for data transmission and reception in the data cell can be transmitted and received from the connected data cell.

[0530] Finally, a new state can be defined.

[0531] Figure 21 is a diagram showing the new state and state transition of the terminal.

[0532] Referring to FIG. 21, when a terminal in the RRC IDLE (2101) state connects to a sync cell, it can transition to the RRC Standby (2103) state through a state transition (2102). In this state, the terminal can receive at least a portion of the RRC configuration for the data cell from the sync cell to enable it to connect quickly and efficiently to the RRC connection state. Afterward, the terminal that has selected an appropriate data cell can transition to the RRC CONNECTED (2105) state through a state transition (2014). And if the terminal in the RRC CONNECTED (2105) state transitions to the RRC INACTIVE (2106) state, the terminal can camp on a data cell other than the sync cell.

[0533] <Fourth Example>

[0534] The fourth embodiment is an example of a dynamic indicator for reducing delay time in the cell reselection process of the second embodiment.

[0535] In the cell reselection evaluation process of the second embodiment, the target for neighboring cell measurement may differ depending on whether the terminal is performing cell reselection based on a trigger that occurs when the RSRP or RSRQ of the serving cell is lower than a specific threshold, or whether it is for exiting idle / inactive mode. Specifically, the serving cell that triggers cell reselection for replacing the serving cell of an idle terminal is a sync cell, and the cell considered for exiting idle / inactive mode and switching to connected mode is a data cell; therefore, the cell list or band required for measurement may differ in each case.

[0536] In existing technology, a serving cell can provide information about the candidate cell list to an idle terminal through system information. However, this approach may not be effective in environments where data cells are dynamically turned on and off, as the terminal must verify and measure the entire cell list and the transmission cycle of system information is long. In other words, to reduce latency, it is necessary to dynamically indicate the list of currently active cells, which can be achieved through a two-step approach. First, the base station can provide the candidate cell list to the terminal semi-statically through system information and / or higher-layer signaling. Additionally, the base station can dynamically inform the terminal of the list of active cells or frequency ranges within the candidate cell list using additional signaling. In this case, the additional signaling may be based on, for example, MAC-CE or Layer-1 signaling (e.g., DCI).

[0537] FIG. 22a is a diagram showing an example of a method for indicating a dynamic cell list or frequency band.

[0538] Referring to FIG. 22a, it is assumed that there is a sync cell (2201) and several data cells (2202), and that among the four data cells, two data cells are activated and the remaining two data cells are deactivated. The sync cell (2201) identifies the four data cells as candidate data cells through system information, and can reduce the number of data cells to be measured by the terminal through dynamic instructions (e.g., MAC CE or DCI-based) depending on the situation. For example, if the DCI (2203) includes a field to indicate the activated data cells among the candidate data cells, and the terminal obtains the value of the corresponding field as 1001 through the DCI, it can recognize that the first and fourth data cells are activated based on this. Therefore, the terminal can perform measurements on the first data cell and the fourth data cell among the configured candidate data cells.

[0539] FIG. 22b is a diagram showing another example of a method for indicating a dynamic cell list or frequency band.

[0540] Referring to FIG. 22b, assume a situation in which a sync cell (2211) and several data cell groups (2212) exist. Each data cell group may again consist of several data cells. The sync cell can dynamically provide a data cell list to the terminal using an SSB (or a signal with various equivalent beams applied). For example, when there are four data cell groups and an SSB burst (2213) containing the SSB of the sync cell with a total of four beams applied is transmitted, each terminal can determine which data cell group is the best through one of the SSB bursts. For example, if the first SSB shows better link performance than the remaining SSBs, the terminal can perform a measurement on the first data cell group. At this time, several data cells may exist within the first data cell group, and an active data cell list can be obtained through the PBCH DMRS, PBCH, MIB within the SSB, or the PDCCH (DCI) that has a QCL relationship with the corresponding SSB.

[0541] The first to fourth embodiments described above may each be operated independently and may be operated together in whole or in part.

[0542] FIG. 23 illustrates a terminal transceiver device according to one embodiment of the present disclosure.

[0543] FIG. 23 illustrates a terminal transceiver device according to one embodiment of the present disclosure. For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description.

[0544] Referring to FIG. 23, the terminal may include a transmitter (2304) comprising an uplink transmission processing block (2301), a multiplexer (2302), and a transmission RF block (2303), a receiver (2308) comprising a downlink reception processing block (2305), a demultiplexer (2306), and a reception RF block (2307), and a control unit (2309). The control unit (2309) can control each of the constituent blocks of the receiver (2308) for receiving a data channel or control channel transmitted by the base station as described above, and each of the constituent blocks of the transmitter (2304) for transmitting an uplink signal.

[0545] In the transmission unit (2304) of the terminal, the uplink transmission processing block (2301) can generate a signal to be transmitted by performing processes such as channel coding and modulation. The signal generated by the uplink transmission processing block (2301) can be multiplexed with other uplink signals by a multiplexer (2302), then processed by a transmission RF block (2303), and then transmitted to a base station.

[0546] The terminal receiver (2308) demultiplexes the signal received from the base station and distributes it to each downlink reception processing block. The downlink reception processing block (2305) can obtain control information or data transmitted by the base station by performing processes such as demodulation and channel decoding on the downlink signal of the base station. The terminal receiver (2308) can support the operation of the control unit (2309) by applying the output result of the downlink reception processing block to the control unit (2309).

[0547] FIG. 24 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0548] As illustrated in FIG. 24, the terminal of the present disclosure may include a processor (2430), a transceiver (2410), and a memory (2420). However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more components or fewer components than those described above. Furthermore, the processor (2430), the transceiver (2410), and the memory (2420) may be implemented in the form of a single chip. According to one embodiment, the transceiver (2410) of FIG. 24 may include the transceiver (2304) and the receiver (2308) of FIG. 23. Additionally, the processor (2430) of FIG. 24 may include the control unit (2309) of FIG. 23.

[0549] According to one embodiment, the processor (2430) can control a series of processes that allow the terminal to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the components of the terminal can be controlled to perform a transmission and reception method of the terminal depending on whether the base station mode is a base station energy saving mode or a base station general mode. The processor (2430) may be one or a plurality of processors, and the processor (2430) can perform a transmission and reception operation of the terminal in a wireless communication system applying the carrier band of the present disclosure described above by executing a program stored in memory (2420).

[0550] The transceiver (2410) can transmit and receive signals with a base station. The signals transmitted and received with the base station may include control information and data. The transceiver (2410) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (2410), and the components of the transceiver (2410) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (2410) can receive a signal through a wireless channel and output it to a processor (2430), and transmit the signal output from the processor (2430) through a wireless channel.

[0551] According to one embodiment, the memory (2420) may store programs and data necessary for the operation of the terminal. Additionally, the memory (2420) may store control information or data included in signals transmitted and received by the terminal. The memory (2420) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, the memory (2420) may be a plurality of. According to one embodiment, the memory (2420) may store a program for performing the transmission and reception operation of the terminal depending on whether the base station mode, which is an embodiment of the present disclosure described above, is a base station energy saving mode or a base station general mode.

[0552] FIG. 25 is a block diagram of a base station according to one embodiment of the present disclosure.

[0553] As illustrated in FIG. 25, the base station of the present disclosure may include a processor (2530), a transceiver (2510), and a memory (2520). However, the components of the base station are not limited to the examples described above. For example, the base station may include more components or fewer components than the components described above. In addition, the processor (2530), the transceiver (2510), and the memory (2520) may be implemented in the form of a single chip.

[0554] The processor (2530) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the components of the base station can be controlled to perform a method of scheduling a terminal depending on whether the base station mode is a base station energy saving mode or a base station general mode. The processor (2530) may be one or a plurality of processors, and the processor (2530) can perform the method of the present disclosure described above by executing a program stored in memory (2520).

[0555] The transceiver (2510) can transmit and receive signals with a terminal. The signals transmitted and received with the terminal may include control information and data. The transceiver (2510) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (2510), and the components of the transceiver (2510) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (2510) can receive a signal through a wireless channel and output it to a processor (2530), and transmit the signal output from the processor (2530) through a wireless channel.

[0556] According to one embodiment, the memory (2520) may store programs and data necessary for the operation of the base station. Additionally, the memory (2520) may store control information or data included in signals transmitted and received by the base station. The memory (2520) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, there may be multiple memories (2520). According to one embodiment, the memory (2520) may store a program for performing the methods of the embodiments of the present disclosure described above.

[0557] In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0558] Meanwhile, the present specification and drawings disclose preferred embodiments of the present disclosure. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the disclosure, and are not intended to limit the scope of the present disclosure. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present disclosure are possible. Furthermore, the first, second, third, and fourth embodiments may be combined and operated together as needed.

[0559] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

In the method of a terminal of a communication system, Step of performing a cell reselection evaluation procedure; A step of identifying whether a suitable cell exists based on the above cell reselection evaluation procedure; It includes a step of operating based on whether the above-mentioned suitable cell exists, The existence of the above suitable cell is identified based on the above cell reselection evaluation procedure, and The above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, or based on a trigger that occurs when the first RSRP (reference signal received power) or first RSRQ (reference signal received quality) of the serving cell is lower than a threshold value, and The above suitable cell satisfies specific conditions, and If the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, the step of operating based on the existence of the above suitable cell is: If the above suitable cell exists, the terminal connects to the above suitable cell and switches to a connected state (connected mode); and A method characterized by including the step of activating a deactivated data cell when the above-mentioned suitable cell does not exist. In paragraph 1, If the above cell reselection evaluation procedure is performed based on a trigger that occurs when the RSRP or RSRQ of the serving cell is lower than a threshold, the step of operating based on the existence of the suitable cell is: If the above suitable cell exists, the terminal performs a camping mode in the above suitable cell; and A method characterized by including a step of finding any other cell when the above-mentioned suitable cell does not exist. In paragraph 1, The above specific conditions are: If the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, it is satisfied based on a threshold value for the second RSRP or second RSRQ, and A method characterized by satisfying the cell ranking when the above cell re-selection evaluation procedure is performed based on a trigger that occurs when the first RSRP or first RSRQ of the serving cell is lower than a threshold value. In paragraph 1, The above suitable cell is: If the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, it is a data cell, and A method characterized by being a sync cell when the above cell reselection evaluation procedure is performed based on a trigger that occurs when the first RSRP or first RSRQ of the serving cell is lower than a threshold value. In paragraph 1, The step of activating the above-mentioned deactivated data cell is: If the above-mentioned deactivated data cell supports a WUR (wake-up receiver), the terminal transmits a WUS (wake-up signal) to the above-mentioned deactivated data cell; and A method characterized by including the step of, if the above-mentioned deactivated data cell does not support WUR, the terminal connecting to a sink cell to activate the above-mentioned deactivated data cell. In paragraph 5, When the above-mentioned deactivated data cell is activated by the connection of the above-mentioned terminal's sink cell, After the sink cell connection of the above terminal and before the data cell connection, the state of the above terminal is one of the first state, the second state, and the third state, and The first state is the RRC (radio resource control) IDLE state; The second state is the RRC INACTIVE state; A method characterized in that the third state can be directly transitioned from the RRC IDLE state through a state transition and can be directly transitioned from the RRC CONNECTED state through a state transition. In paragraph 1, A step of receiving first information about a cell list semi-statically from a base station; and A method characterized by further including the step of dynamically receiving second information from a base station regarding an activated cell list among the cell lists related to the first information. In paragraph 1, A method characterized by further including the step of dynamically receiving third information about a cell list from a base station via an SSB. In a terminal of a communication system, At least one transceiver; At least one processor connected to the above at least one transceiver so as to be able to communicate; and Connected to communicate with at least one processor and capable of executing individually or in any combination of the at least one processor, the terminal: Perform the cell reselection evaluation procedure, and Based on the above cell reselection evaluation procedure, identify whether a suitable cell exists, and It includes memory that stores instructions to operate based on whether a suitable cell exists, and The above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, or based on a trigger that occurs when the first RSRP (reference signal received power) or first RSRQ (reference signal received quality) of the serving cell is lower than a threshold value, and The above suitable cell satisfies specific conditions, and When the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, the memory storing an instruction to operate based on the existence of the above suitable cell is: If the above suitable cell exists, the terminal connects to the above suitable cell and switches to a connected state (connected mode), and A terminal characterized by storing a command to activate a deactivated data cell when the above-mentioned suitable cell does not exist. In Paragraph 9, When the above cell reselection evaluation procedure is performed based on a trigger that occurs when the RSRP or RSRQ of the serving cell is lower than a threshold, a memory storing an instruction to operate based on the existence of the suitable cell is: If the above suitable cell exists, the terminal performs camping mode in the above suitable cell, and A terminal characterized by storing a command to perform a procedure to find any other random cell when the above-mentioned suitable cell does not exist. In Paragraph 9, The above specific conditions are: If the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, it is satisfied based on a threshold value for the second RSRP or second RSRQ, and A terminal characterized by being satisfied based on cell ranking when the above cell re-selection evaluation procedure is performed based on a trigger that occurs when the first RSRP or first RSRQ of a serving cell is lower than a threshold value. In Paragraph 9, The above suitable cell is: If the above cell reselection evaluation procedure is performed based on the occurrence of uplink traffic or downlink traffic, it is a data cell, and A terminal characterized as being a sync cell when the above cell reselection evaluation procedure is performed based on a trigger that occurs when the first RSRP or first RSRQ of the serving cell is lower than a threshold value. In Paragraph 9, The memory storing the instruction to activate the above-mentioned deactivated data cell is: If the above-mentioned deactivated data cell supports a WUR (wake-up receiver), the terminal transmits a WUS (wake-up signal) to the above-mentioned deactivated data cell, and A terminal characterized by storing a command that, when the above-mentioned deactivated data cell does not support WUR, the terminal connects to a sink cell to activate the above-mentioned deactivated data cell. In Paragraph 13, When the above-mentioned deactivated data cell is activated by the connection of the above-mentioned terminal's sink cell, After the sink cell connection of the above terminal and before the data cell connection, the state of the above terminal is one of the first state, the second state, and the third state, and The first state is the RRC (radio resource control) IDLE state; The second state is the RRC INACTIVE state; A terminal characterized in that the third state can be directly transitioned from the RRC IDLE state through a state transition and can be directly transitioned from the RRC CONNECTED state through a state transition. In Paragraph 9, The above memory is: First information regarding the cell list is received semi-statically from the base station, and A terminal characterized by further storing a command to dynamically receive second information regarding an activated cell list among the cell lists related to the first information above from a base station.

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