Method and device for energy saving in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. In addition, the present disclosure provides a method and a device for reducing a delay time for reducing energy consumption of a base station in a mobile communication system. A method performed by a terminal in a wireless communication system according to an embodiment of the present disclosure may comprise the steps of: receiving a system information block from a first cell on which the terminal in a radio resource control (RRC) idle or RRC inactive state is camped; receiving a physical downlink control channel (PDCCH) including a downlink control information (DCI) format from the first cell, wherein the DCI format includes information for triggering activation of a second cell; performing a synchronization procedure to the second cell after a first time from a point in time at which the PDCCH has been received; and receiving data traffic from the second cell.

Description

Method and device for energy saving in wireless communication systems

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

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

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

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

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

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

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

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

[0009] The technical problems to be achieved in the present disclosure are not limited to those mentioned above, and other technical problems not mentioned can be considered by a person having ordinary skill in the art from the various embodiments of the present disclosure described below.

[0010] In a wireless communication system according to one embodiment of the present disclosure, a method performed by a terminal may include the steps of: receiving a system information block from a first cell on which the terminal is camped in an RRC (radio resource control) idle or RRC inactive state; receiving a PDCCH (physical downlink control channel) including a DCI (downlink control information) format from the first cell; the DCI format including information for triggering activation of a second cell; performing a synchronization procedure to the second cell after a first time from the time of receiving the PDCCH; and receiving data traffic from the second cell.

[0011] In another embodiment of the present disclosure, a method performed by a base station associated with a first cell in a wireless communication system includes the steps of transmitting a system information block to a terminal in an RRC standby or RRC inactive state, the terminal being camped on the first cell, transmitting a PDCCH including a DCI format to the terminal, the DCI format including information for triggering activation of a second cell having data traffic to be transmitted to the terminal, and transmitting information indicating activation to the second cell, wherein a synchronization procedure to the second cell can be performed after a first time from the time point at which the PDCCH is transmitted.

[0012] In a wireless communication system according to another embodiment of the present disclosure, a terminal includes a transceiver and a processor, and the processor is configured to receive a system information block from a first cell on which the terminal is camped in an RRC standby or RRC inactive state, receive a PDCCH including a DCI format from the first cell, the DCI format including information for triggering activation of a second cell, perform a synchronization procedure to the second cell after a first time from the time of receiving the PDCCH, and receive data traffic from the second cell.

[0013] In another embodiment of the present disclosure, in a wireless communication system, a base station associated with a first cell includes a transceiver and a processor, wherein the processor transmits a system information block to a terminal in an RRC standby or RRC inactive state, the terminal is camped on the first cell, and transmits a PDCCH including a DCI format to the terminal, the DCI format including information for triggering activation of a second cell having data traffic to be transmitted to the terminal, and is configured to transmit information instructing activation to the second cell, and a synchronization procedure to the second cell can be performed after a first time from the time point at which the PDCCH is transmitted.

[0014] The various embodiments of the present disclosure described above are only some of the embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by a person having ordinary knowledge in the relevant technical field based on the detailed description to be described below.

[0015] 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 solved and high energy efficiency can be achieved.

[0016] The effects that can be obtained from various embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art based on the detailed description below.

[0017] FIG. 1 illustrates the basic structure of a time-frequency resource domain of a 5G system according to one embodiment of the present disclosure.

[0018] FIG. 2 illustrates a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0019] FIG. 3 illustrates a random access procedure according to one embodiment of the present disclosure.

[0020] FIG. 4 illustrates a procedure for a terminal to report terminal capability information to a base station according to one embodiment of the present disclosure.

[0021] FIG. 5 illustrates a control resource set (CORESET) as a time-frequency resource to which a physical downlink control channel (PDCCH) is mapped according to one embodiment of the present disclosure.

[0022] FIG. 6 illustrates the mapping of downlink control information (DCI) and de-modulation reference signal (DMRS) in a resource element group (REG), which is a basic unit of a downlink control channel according to one embodiment of the present disclosure.

[0023] FIG. 7 illustrates base station beam allocation according to transmission configuration indicator (TCI) state settings according to one embodiment of the present disclosure.

[0024] FIG. 8 illustrates a hierarchical signaling method for dynamic allocation of PDCCH beams of NR according to one embodiment of the present disclosure.

[0025] FIG. 9 illustrates a TCI indication MAC CE (medium access control-control element) signaling structure for PDCCH DMRS according to one embodiment of the present disclosure.

[0026] FIG. 10 is a diagram for explaining a method for a base station and a terminal to transmit and receive data by taking into account downlink data channels and rate matching resources according to one embodiment of the present disclosure.

[0027] FIG. 11 illustrates an aperiodic CSI (channel state information) reporting method when a CSI-RS (channel state information-reference signal) offset is 0 according to one embodiment of the present disclosure.

[0028] FIG. 12 illustrates an aperiodic CSI reporting method when a CSI-RS offset is 1 according to one embodiment of the present disclosure.

[0029] FIG. 13 illustrates settings for a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

[0030] FIG. 14 illustrates DRX (Discontinuous Reception) in a 5G communication system according to one embodiment of the present disclosure.

[0031] FIG. 15 is a drawing for explaining an existing network communication system to which one embodiment of the present disclosure is applicable.

[0032] FIG. 16a and FIG. 16b are diagrams for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0033] FIG. 17a and FIG. 17b are diagrams for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0034] FIG. 18 is a diagram illustrating a classification of latency until a terminal camped on a sync cell according to a cell structure according to one embodiment of the present disclosure receives all packets after accessing a data cell when data traffic occurs.

[0035] FIG. 19 is a diagram illustrating a two-octet structure of a trigger for fast SCell (secondary cell) activation based on MAC CE according to one embodiment of the present disclosure.

[0036] FIG. 20 is a diagram showing a timeline for fast SCell activation according to one embodiment of the present disclosure.

[0037] FIG. 21a, FIG. 21b, and FIG. 21c illustrate three timelines from the time traffic is generated to the time when a data cell is activated in a terminal according to one embodiment of the present disclosure.

[0038] FIG. 22 illustrates signaling between a terminal and a base station operating based on fast data cell activation according to one embodiment of the present disclosure.

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

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

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

[0042] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0043] For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description. Furthermore, when describing the present disclosure, detailed descriptions of known functions or configurations may be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on their functions in the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the contents throughout this specification.

[0044] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided solely to ensure that the 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. Like reference numerals designate like elements throughout the specification.

[0045] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0046] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0047] Here, the term '~ part' used in this embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ part' performs certain roles. However, the '~ part' is not limited to software or hardware. The '~ part' may be configured to be on an addressable storage medium or may be configured to play one or more processors. Therefore, as an example, the '~ part' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, 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'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within a device or secure multimedia card. In addition, in an embodiment, the '~parts' may include one or more processors.

[0048] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc. are provided as examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0049] In the following description, the terms "physical channel" and "signal" may be used interchangeably with data or control signals. For example, while PDSCH (physical downlink shared channel) refers to a physical channel through which data is transmitted, PDSCH may also be used to refer to data. That is, in the present disclosure, the expression "transmitting a physical channel" may be interpreted equivalently to the expression "transmitting data or a signal through a physical channel."

[0050] Hereinafter, in the present disclosure, upper layer signaling (upper layer signaling) refers to a signal transmission method in which a base station transmits a signal to a terminal using a downlink data channel of a physical layer, or a terminal transmits a signal to a base station using an uplink data channel of a physical layer. Upper layer signaling can be understood as radio resource control (RRC) signaling, PDCP signaling, or a media access control (MAC) control element (CE).

[0051] For convenience of explanation, this disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th generation mobile communications standard) standards. However, this disclosure is not limited to these terms and names and can be equally applied to systems conforming to other standards. Furthermore, the term "terminal" can refer to not only mobile phones, smartphones, IoT devices, and sensors, but also other wireless communication devices.

[0052] Hereinafter, a base station is an entity that performs resource allocation of a terminal, and may be at least one of a gNode B, a gNB, an eNode B, an eNB, a Node B, a BS (Base Station), a wireless access unit, a base station controller, or a node on a network. The terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. Of course, the present invention is not limited to the above examples.

[0053] To handle the explosive growth in mobile data traffic, the initial standards for the 5G system, or New Radio access technology (NR), the next-generation communication system following LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)) and LTE-A (LTE-Advanced or E-UTRA Evolution), have been completed. While existing mobile communication systems have focused on conventional voice / data communications, the 5G system aims to satisfy various services and requirements, such as enhanced Mobile BroadBand (eMBB) services for improving existing voice / data communications, Ultra-Reliable and Low Latency Communication (URLLC) services for high reliability / ultra-low latency communications, and massive Machine Type Communication (MTC) services for supporting massive machine-to-machine communications.

[0054] While the transmission bandwidth of existing LTE and LTE-A systems per single carrier is limited to a maximum of 20MHz, the 5G system aims to provide ultra-high-speed data services of up to several Gbps by utilizing a much wider ultra-wide bandwidth. Accordingly, the 5G system is considering ultra-high frequency bands from several GHz 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 the 5G system through frequency reallocation or allocation among frequency bands included in the hundreds of MHz to several GHz used in existing mobile communication systems.

[0055] Radio waves in the ultra-high frequency band are sometimes called millimeter waves (mmWave) because their wavelengths are on the order of millimeters. However, in the ultra-high frequency band, the path loss of radio waves increases in proportion to the frequency band, reducing the coverage of mobile communication systems.

[0056] In order to overcome the disadvantage of reduced coverage in the above ultra-high frequency band, beamforming technology can be applied, which uses multiple antennas to concentrate the radiated energy of radio waves to a predetermined target point and increase the transmission distance of radio waves. That is, the beam width of the signal to which the beamforming technology is applied becomes relatively narrow, and the radiated energy is concentrated within the narrowed beam width, thereby increasing the transmission distance. The beamforming technology can be applied to both the transmitter and the receiver. In addition to the effect of increasing coverage, the beamforming technology has the effect of reducing interference in areas other than the beamforming direction. In order for the beamforming technology to operate properly, accurate measurement and feedback methods of the transmission / reception beams are required. The beamforming technology can be applied to a control channel or a data channel that corresponds one-to-one between a predetermined terminal and a base station. Additionally, beamforming technology can be applied to common signals transmitted by a base station to multiple terminals within a 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 transmits signals by changing the beam direction, is additionally applied so that the common signal can reach terminals located at any location within the cell.

[0057] Another requirement for 5G systems is ultra-low latency services, with transmission delays of approximately 1 ms between transmitters and receivers. One way to reduce transmission delay is to design a frame structure based on a short TTI (Transmission Time Interval), which is shorter than that of LTE and LTE-A. A TTI is the basic time unit used for scheduling, and the TTI of existing LTE and LTE-A systems is 1 ms, which corresponds to the length of one subframe. For example, to meet the requirements for ultra-low latency services in the 5G system, possible short TTIs are 0.5 ms, 0.25 ms, and 0.125 ms, which are shorter than those of existing LTE and LTE-A systems.

[0058] FIG. 1 illustrates 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 illustrating the basic structure of a time-frequency resource domain, which is a radio resource domain in which data or control channels of a 5G system are transmitted.

[0059] Referring to Figure 1, the horizontal axis in Figure 1 represents the time domain and the vertical axis represents the frequency domain. The minimum transmission unit in the time domain of the 5G system is an OFDM (Orthogonal Frequency Division Multiplexing) symbol. (102) symbols are grouped together to form one slot (106), A plurality of slots can be combined to form a 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 entire system transmission bandwidth is a total of N BW It can be composed of (104) subcarriers.

[0060] The basic unit of resources in the time-frequency domain 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 a resource block in the frequency domain. It can be defined as (110) consecutive subcarriers. In 5G systems, =12, and the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0061] In a 5G system, a base station maps data in RB units, and scheduling can be performed for RBs, which typically constitute a slot for a given terminal. That is, in a 5G system, the basic time unit for scheduling may be a slot, and the basic frequency unit for scheduling may be an RB.

[0062] Number of OFDM symbols It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols. For example, if the normal CP is applied, =14, when Extended CP is applied =12 can be. Extended CP can be applied to a system with a relatively long transmission distance than the general CP, so that orthogonality between symbols can be maintained. In the case of the general CP, since the ratio of the CP length to the symbol length is maintained at a constant value, the overhead due to the CP can be maintained constant regardless of the subcarrier spacing. That is, if the subcarrier spacing is small, the symbol length becomes longer, and thus the CP length can also become longer. Conversely, if the subcarrier spacing is large, the symbol length becomes shorter, and thus the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0063] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to meet diverse services and requirements. For example,

[0064] - From the perspective of the operating frequency band, the larger the subcarrier spacing, the more advantageous it is for recovering phase noise in the high-frequency band.

[0065] - From the perspective of transmission time, if the subcarrier spacing is large, the symbol length in the time domain becomes shorter, and consequently, the slot length becomes shorter, which is advantageous for supporting ultra-low delay services such as URLLC.

[0066] - From a cell size perspective, a longer CP length allows for larger cells to be supported, so a smaller subcarrier spacing allows for relatively larger cells to be supported. In mobile communications, a cell is a concept that refers to the area covered by a single base station.

[0067] The above subcarrier spacing, CP length, etc. are essential information for OFDM transmission and reception. The base station and the terminal must recognize the subcarrier spacing, CP length, etc. as common values ​​to enable smooth transmission and reception. [Table 1] shows the subcarrier spacing configuration (μ), subcarrier spacing ( ), which represents the relationship between CP length.

[0068]

[0069] [Table 2] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of the general CP. ), number of slots per frame ( ), number of slots per subframe ( ) is indicated.

[0070]

[0071] [Table 3] shows the number of symbols per slot for each subcarrier spacing setting (μ) in the case of extended CP. ), number of slots per frame ( ), number of slots per subframe ( ) is indicated.

[0072]

[0073] In the early stages of 5G system deployment, coexistence or dual-mode operation with existing LTE and / or LTE-A (hereinafter referred to as LTE / LTE-A) systems is expected. This allows existing LTE / LTE-A to provide stable system operation to terminals, while the 5G system can provide enhanced services to these terminals. Therefore, the 5G system's frame structure must at least include the LTE / LTE-A frame structure or essential parameter set (subcarrier spacing = 15 kHz).

[0074] For example, comparing a frame structure with a subcarrier spacing setting μ=0 (hereinafter referred to as frame structure A) and a frame structure with a subcarrier spacing setting μ=1 (hereinafter referred to as frame structure B), compared to frame structure A, the subcarrier spacing and RB size of frame structure B are twice as large, and the slot length and symbol length 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.

[0075] Generalizing the frame structure of the above 5G system provides high scalability by ensuring that essential parameter sets, such as subcarrier spacing, CP length, and slot length, have integer multiple relationships for each frame structure. Furthermore, a fixed-length subframe of 1 ms can be defined to represent a reference time unit independent of the frame structure.

[0076] The above frame structure can be applied to correspond to various scenarios. From a cell size perspective, since a longer CP length can support a larger cell, the frame structure A can support a relatively larger cell than the frame structure B. From an operating frequency band perspective, since a larger subcarrier spacing is advantageous for phase noise recovery in a high-frequency band, the frame structure B can support a relatively higher operating frequency than the frame structure A. From a service perspective, since a shorter slot length, which is a basic time unit of scheduling, is advantageous for supporting an ultra-low delay service such as URLLC, the frame structure B can be relatively more suitable for the URLLC service than the frame structure A.

[0077] In the following description of the present disclosure, uplink (UL) may refer to a wireless link through which a terminal transmits data or a control signal to a base station, and downlink (DL) may refer to a wireless link through which a base station transmits data or a control signal to a terminal.

[0078] In the initial access stage where a terminal first accesses the system, the terminal can synchronize downlink time and frequency from a synchronization signal transmitted by a base station through cell search, and obtain a cell identifier (cell ID). Then, the terminal can receive a Physical Broadcast Channel (PBCH) using the obtained cell ID, and obtain a Master Information Block (MIB), which is essential system information, from the PBCH. Additionally, the terminal can obtain cell-common transmission and reception-related control information by receiving system information (System Information Block, SIB) transmitted by the base station. The cell-common transmission and reception-related control information may include random access-related control information, paging-related control information, and common control information for various physical channels.

[0079] A synchronization signal is a signal that serves as a reference for cell search, and subcarrier spacing can be applied to suit channel environments such as phase noise for each frequency band. In the case of a data channel or control channel, as described above, different subcarrier spacings can be applied depending on the service type in order to support various services.

[0080] FIG. 2 illustrates a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0081] For the purpose of explanation, the following components can be defined:

[0082] - PSS (Primary Synchronization Signal): This signal serves as the basis for DL ​​time / frequency synchronization and provides some cell ID information.

[0083] - SSS (Secondary Synchronization Signal): Serves as a reference for DL ​​time / frequency synchronization and provides some remaining information, including the cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0084] - PBCH (Physical Broadcast Channel): Provides MIB (Master Information Block), which is essential system information required for transmission and reception of data channels and control channels of the terminal. The essential system information may include search space-related control information indicating radio resource mapping information of the control channel, scheduling control information for a separate data channel that transmits system information, and SFN (System Frame Number), which is a frame-unit index that serves as a timing reference.

[0085] - SS / PBCH Block (Synchronization Signal / PBCH Block or SSB): An SS / PBCH block consists of N OFDM symbols and is a combination of PSS, SSS, PBCH, etc. In a system 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. The base station can transmit up to L SS / PBCH blocks, and the L SS / PBCH blocks are mapped within a half frame (0.5 ms). In addition, the L SS / PBCH blocks are periodically repeated in units of a predetermined period P. The period P can be notified to the terminal by the base station through signaling. If there is no separate signaling for the period P, the terminal applies a pre-agreed default value.

[0086] FIG. 2 illustrates an example in which beam sweeping is applied to SS / PBCH block units over time. Referring to FIG. 2, 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 at time t1 (201). 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 at time t2 (202). 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, terminal 1 (205) may have difficulty in obtaining 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.

[0087] 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 at a certain level or higher. Furthermore, during a handover procedure in which the terminal moves from the current cell to a neighboring cell, the terminal may receive SS / PBCH blocks from the neighboring cell to determine the radio link quality of the neighboring cell and obtain time / frequency synchronization with the neighboring cell.

[0088] After the terminal acquires MIB and system information from the base station through the initial access procedure, the terminal can perform a random access procedure to transition the link with the base station to a 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 is described in detail below with reference to FIG. 3.

[0089] FIG. 3 illustrates a random access procedure according to one embodiment of the present disclosure. FIG. 3 illustrates an example of a random access procedure, and the present disclosure is not limited thereto. Furthermore, the present disclosure is not limited to the 4-step random access procedure illustrated in FIG. 3, and can also be applied to a 2-step random access procedure (transmitting and receiving message A (a message including information corresponding to message 1 and message 3) and transmitting and receiving message B (a message including information corresponding to message 2 and message 4)).

[0090] Referring to FIG. 3, in the 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 first 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 can arbitrarily select which random access preamble to use within the random access preamble set given in advance by system information. In addition, the initial transmission power of the random access preamble can be determined according to the path loss between the terminal and the base station measured by the terminal. In addition, the terminal can 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.

[0091] In the second step (320), the base station transmits an uplink transmission timing adjustment command to the terminal based on the transmission delay value measured from the random access preamble received in the first step (310). In addition, the base station may transmit uplink resources and power control commands to be used by the terminal as scheduling information. The scheduling information may include control information regarding the terminal's uplink transmission beam.

[0092] If the terminal does not receive the Random Access Response (RAR) (or message 2), which is scheduling information for message 3, from the base station within a predetermined time in the second step (320), the first step (310) can 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 transmitting it while increasing the transmission power of the random access preamble by a predetermined step (power ramping).

[0093] In the third step (330), the terminal transmits uplink data (message 3) including its terminal ID to the base station through an 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). In addition, 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 mean the first uplink data signal that the terminal transmits to the base station after transmitting the random access preamble.

[0094] 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) including the ID of the terminal that transmitted uplink data in step 3 (330) to the terminal. If the terminal receives the signal transmitted by the base station in step 4 (340) from the base station, it can determine that the random access has been successful. In addition, the terminal can transmit HARQ-ACK information indicating whether the message 4 has been successfully received to the base station through an uplink control channel (Physical Uplink Control Channel, PUCCH).

[0095] If the data transmitted by the terminal in step 3 (330) collides with data from another terminal, causing the base station to fail to receive a data signal from the terminal, the base station may not transmit any more data to the terminal. Accordingly, if the terminal fails to receive the data transmitted from the base station in step 4 (340) within a certain period of time, it may determine that the random access procedure has failed and restart from step 1 (310).

[0096] Upon successful 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 base station receives UE capability information from the connected terminal and can adjust scheduling by referencing the UE capability information of the terminal. Through the UE capability information, the terminal can inform the base station whether it supports a certain function, the maximum allowable value of the function supported by the terminal, etc. Accordingly, the UE capability information reported by each terminal to the base station may have different values ​​for each terminal.

[0097] For example, the terminal may report UE capability information including at least a portion of the following control information as the UE capability information to the base station.

[0098] - Control information related to frequency bands supported by the terminal

[0099] - Control information related to channel bandwidth supported by the terminal

[0100] - Control information related to the maximum modulation method supported by the terminal

[0101] - Control information related to the maximum number of beams supported by the terminal

[0102] - Control information related to the maximum number of layers supported by the terminal

[0103] - Control information related to CSI reporting supported by the terminal

[0104] - Control information on whether the terminal supports frequency hopping

[0105] - Bandwidth-related control information when supporting carrier aggregation (CA)

[0106] - Control information on whether cross carrier scheduling is supported when carrier aggregation is supported.

[0107] FIG. 4 illustrates a procedure for a terminal to report terminal capability information to a base station according to one embodiment of the present disclosure.

[0108] Referring to FIG. 4, at step 410, the base station (402) can transmit a UE capability information request message to the terminal (401). In response to the base station's request for UE capability information, the terminal transmits UE capability information to the base station at step 420.

[0109] Through the above process, a terminal connected to a base station is in an RRC connected (RRC_CONNECTED) state, enabling one-to-one communication. Conversely, a terminal that is not connected is in an RRC idle (RRC_IDLE) state. The behavior of a terminal in this state can be categorized as follows:

[0110] - Operates a terminal-specific DRX (Discontinuous Reception) cycle set by the upper layer,

[0111] - The action of receiving a paging message from the core network;

[0112] - Obtain system information, and / or

[0113] - Measurement actions related to surrounding cells and cell reselection.

[0114] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed during initial access. In addition to the actions performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following actions:

[0115] - Storage of AS (Access stratum) information required for cell access.

[0116] - Terminal-specific DRX cycle operation set by the RRC layer,

[0117] - Setting up and periodically updating an RNA (RAN-based notification area) that can be utilized during handover by the RRC layer, and / or

[0118] - Monitoring of RAN-based paging messages transmitted via I-RNTI (inactive-radio network temporary identifier).

[0119] Below, a scheduling method is described in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data.

[0120] Downlink Control Information (DCI) is control information transmitted from a base station to a terminal via the downlink. It may include downlink data scheduling information or uplink data scheduling information for a given terminal. Typically, the base station independently channel-codes DCI for each terminal and then transmits it to each terminal via the Physical Downlink Control Channel (PDCCH).

[0121] The base station can operate by applying a predetermined DCI format according to the purpose, such as whether it is scheduling information for downlink data (downlink assignment) for the terminal to be scheduled, whether it is scheduling information for uplink data (uplink grant), and whether it is DCI for power control.

[0122] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), a physical channel for downlink data transmission. Scheduling information, such as the specific mapping location in the time and frequency domains of the PDSCH, modulation scheme, HARQ-related control information, and power control information, can be provided by the base station to the terminal via DCI related to downlink data scheduling information among the DCIs transmitted via the PDCCH.

[0123] A terminal can transmit uplink data to a base station via the Physical Uplink Shared Channel (PUSCH), 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 to the terminal by the base station via DCI related to uplink data scheduling information, among the DCIs transmitted via the PDCCH.

[0124] FIG. 5 illustrates a control resource set (CORESET) as a time-frequency resource to which a PDCCH is mapped according to one embodiment of the present disclosure.

[0125] Referring to FIG. 5, two control resource sets (Control Resource Set #1 (501), Control Resource Set #2 (502)) can be set within a UE bandwidth part (510) along the frequency axis and within one slot (520) along the time axis. The Control Resource Sets (501, 502) can be set to specific frequency resources (503) within the entire UE bandwidth part (510) along the frequency axis. The Time Axis can be set to one or more OFDM symbols, and this can be defined as the Control Resource Set Duration (504).

[0126] 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.

[0127] A base station can configure one or more CORESETs for a terminal through higher layer signaling (e.g., system information, MIB (Master Information Block), RRC (Radio Resource Control) signaling). Configuring a CORESET for a terminal may mean providing information such as a CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information that the base station provides to the terminal to configure a CORESET may include at least some of the information included in [Table 4].

[0128]

[0129] CORESET is in the frequency domain It can be composed of RBs and in the time domain It can be composed of symbols. The 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 one CORESET, REGs can be indexed in time-first order, starting with REG index 0 from the first OFDM symbol of the CORESET, the lowest RB.

[0130] Interleaved and non-interleaved transmission methods for PDCCH can be supported. The base station can configure whether to use interleaved or non-interleaved transmission for each CORESET to the terminal through upper layer signaling. Interleaving can be performed in units of REG bundles. A REG bundle can be defined as a set of one or more REGs. The terminal can determine the CCE-to-REG mapping method in the corresponding CORESET based on whether to use interleaved or non-interleaved transmission as configured by the base station, as shown in [Table 5] below.

[0131]

[0132] The base station can inform the terminal of configuration information such as which symbol within the slot the PDCCH is mapped to and the transmission cycle through signaling.

[0133] FIG. 6 illustrates the mapping of DCI and DMRS in REG, which is a basic unit of a downlink control channel according to one embodiment of the present disclosure.

[0134] Referring to FIG. 6, the basic unit of the downlink control channel, i.e., REG (603), may include both REs to which DCI is mapped and areas to which DMRS (605), which is a reference signal for decoding the REs, is mapped. Additionally, three DMRSs (605) may be transmitted within one REG (603).

[0135] Hereinafter, the search space of the PDCCH is described. The number of CCEs required to transmit the 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, a single downlink control channel can be transmitted through L CCEs. The UE performs blind decoding, which detects a signal without knowing information about the downlink control channel, and for this purpose, 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 UE should attempt to decode at a given aggregation level. Since there are various aggregation levels that create a single group with 1, 2, 4, 8, or 16 CCEs, the UE can have multiple search spaces. A search space set can be defined as the set of search spaces at all established aggregation levels.

[0136] Search spaces can be classified into a common search space (CSS) and a UE-specific search space (USS). A certain group of UEs or all UEs can scan the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling for the System Information Block (SIB) or paging messages. For example, a UE can receive scheduling allocation information for the PDSCH for system information reception by scanning the common search space of the PDCCH. In the case of the common search space, since a certain group of UEs or all UEs must receive the PDCCH, it can be defined as a set of pre-arranged CCEs. UEs can receive scheduling allocation information for the PDSCH or PUSCH by scanning the UE-specific search space of the PDCCH. The UE-specific search space can be defined UE-specifically as a function of the UE's ID and various system parameters.

[0137] The base station can set the search space configuration information of the PDCCH to the terminal through higher layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can set the number of PDCCH candidates in each aggregation level L, the monitoring period for the search space, the monitoring occasion for each symbol within the slot for the search space, the search space type (common search space or terminal-specific search space), the combination of the DCI format and RNTI to be monitored in the corresponding search space, the CORESET index to be monitored for the search space, etc. to the terminal. For example, the parameters for the search space for the PDCCH may include information such as the following [Table 6].

[0138]

[0139]

[0140]

[0141] Depending on the configuration information, the base station may configure one or more search space sets for the terminal. In some embodiments, the base station may configure 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.

[0142] According to the configuration information, one or more search space sets 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 terminal-specific search spaces.

[0143] In a common search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0144] - DCI format 0_0 / 1_0 with CRC (cyclic redundancy check) scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0145] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0146] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0147] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0148] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0149] - DCI format 2_4 with CRC scrambled by CI-RNTI

[0150] - DCI format 2_5 with CRC scrambled by AI-RNTI

[0151] - DCI format 2_6 with CRC scrambled by PS-RNTI

[0152] - DCI format 2_7 with CRC scrambled by PEI-RNTI

[0153] In a terminal-specific search space, a terminal can monitor the following combinations of DCI formats and RNTIs, although these are not limited to the following examples.

[0154] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0155] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0156] The above RNTIs may follow the following definitions and uses:

[0157] C-RNTI (Cell RNTI): For terminal-specific PDSCH or PUSCH scheduling purposes.

[0158] TC-RNTI (Temporary Cell RNTI): For terminal-specific PDSCH scheduling purposes

[0159] CS-RNTI (Configured Scheduling RNTI): Used for semi-statically configured terminal-specific PDSCH scheduling.

[0160] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling in the random access phase.

[0161] P-RNTI (Paging RNTI): Used for scheduling PDSCH where paging is transmitted.

[0162] SI-RNTI (System Information RNTI): Used for scheduling PDSCH where system information is transmitted.

[0163] INT-RNTI (Interruption RNTI): Used to indicate whether PDSCH is punctured.

[0164] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to indicate power control commands for PUSCH.

[0165] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to indicate power control commands for PUCCH.

[0166] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to indicate power control commands for SRS.

[0167] The DCI formats described above can follow the definitions shown in [Table 7] below.

[0168] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs2_4Notifying the PRB(s) and OFDM symbol(s) where UE cancels the corresponding UL transmission from the UE2_5Notifying the availability of soft resources2_6Notifying the power saving information outside DRX Active Time for one or more UEs2_7Notifying paging early indication and TRS availability indication for one or more UEs.3_0Scheduling of NR sidelink in one cell3_1Scheduling of LTE sidelink in one cell4_0Schedulng of PDSCH with CRC scrambled by MCCH-RNTI / G-RNTI for broadcast4_1Schedulng of PDSCH with CRC scrambled by G-RNTI / GCS-RNTI for multicast4_2Schedulng of PDSCH with CRC scrambled by G-RNTI / GCS-RNTI for multicast.

[0169] CORESET p, the search space of aggregation level L in the search space set s can be expressed as the following mathematical formula.

[0170] [Mathematical Formula 1]

[0171]

[0172] - L: Integration level

[0173] - : Carrier Index

[0174] - : Total number of CCEs existing within the control region p

[0175] - : slot index

[0176] - : Number of PDCCH candidates for aggregation level L

[0177] - = 0,..., -1: PDCCH candidate index of aggregation level L

[0178] - i=0,...,L-1

[0179] - , , A0=39827, A1=39829, A2=39839, D=65537

[0180] - : Terminal identifier

[0181] The value can be 0 for a common search space.

[0182] In the case of a terminal-specific search space, the value may correspond to a value that changes depending on the terminal's ID (C-RNTI or ID set to the terminal by the base station) and the time index.

[0183] Below, a method for setting a TCI state for a PDCCH (or PDCCH DMRS) in a 5G communication system is described in detail.

[0184] 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 TCI state is to notify the QCL (Quasi co-location) relationship between the PDCCH (or PDCCH DMRS) and other RSs or channels. When a certain reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed with each other, it means that the terminal is allowed to apply some or all of the large-scale channel parameters estimated at the antenna port A to the channel measurement from the antenna port B. QCL may need to relate 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) radio resource management (RRM) affected by average gain, and 4) beam management (BM) affected by spatial parameters. Accordingly, NR supports four types of QCL relationships, as shown in Table 8 below.

[0185] QCL typeLarge-scale characteristicsADoppler shift, Doppler spread, average delay, delay spreadBDoppler shift, Doppler spreadCDoppler shift, average delayDSpatial Rx parameter

[0186] 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.

[0187] The above QCL relationship can be set to 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 set one or more TCI states to the terminal and inform the RS referencing the ID of the TCI state, i.e., up to two QCL relationships (qcl-Type1, qcl-Type2) for the target RS. At this time, each QCL information (QCL-Info) included in the above TCI state includes the serving cell index and BWP index of the reference RS indicated by the corresponding QCL information, the type and ID of the reference RS, and the QCL type as shown in Table 8 above.

[0188]

[0189] FIG. 7 illustrates base station beam allocation according to TCI state setting according to one embodiment of the present disclosure.

[0190] 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 the antenna ports referencing the different TCI states 700, 705, or 710 have different spatial Rx parameters, i.e., are associated with different beams, by setting the qcl-Type2 parameter included in the three TCI states (700, 705, 710) to be associated with the CSI-RS or SSB corresponding to the different beams and to QCL type D.

[0191] Specifically, the TCI state combinations applicable to the PDCCH DMRS antenna port are as shown in Table 10 below. The fourth row in Table 10 is the combination assumed by the terminal before RRC configuration, and configuration after RRC is not possible.

[0192] Valid TCIstate ConfigurationDL RS 1qcl-Type1DL RS 2(if configured)qcl-Type2(if configured)1TRSQCL-TypeATRSQCL-TypeD2TRSQCL-TypeACSI-RS (BM)QCL-TypeD3CSI-RS (CSI)QCL-TypeA 4SS / PBCH BlockQCL-TypeASS / PBCH BlockQCL-TypeD

[0193] NR supports a hierarchical signaling method as illustrated in FIG. 8 for dynamic allocation of PDCCH beams.

[0194] FIG. 8 illustrates a hierarchical signaling method for dynamic allocation of PDCCH beams of NR according to one embodiment of the present disclosure.

[0195] Referring to FIG. 8, the base station can set N TCI states (805, 810, ..., 820) to the terminal via RRC signaling (800), and can set some of them as TCI states for CORESET (825). Thereafter, the base station can indicate one of the TCI states (830, 835, 840) for CORESET to the terminal via MAC CE signaling (845). Thereafter, the terminal receives the PDCCH based on the beam information included in the TCI state indicated by the MAC CE signaling.

[0196] FIG. 9 illustrates a TCI indication MAC CE signaling structure for PDCCH DMRS according to one embodiment of the present disclosure.

[0197] Referring to FIG. 9, the TCI indication MAC CE signaling for the PDCCH DMRS consists of 2 bytes (16 bits) and includes 1 bit of reserved bit (910), 5 bits of serving cell ID (915), 2 bits of BWP ID (920), 2 bits of CORESET ID (925), and 6 bits of TCI state ID (930).

[0198] A base station can indicate one of the TCI state lists included in the CORESET configuration via MAC CE signaling. Until another TCI state is indicated to the corresponding CORESET via another MAC CE signaling, the terminal assumes that the same QCL information applies to all one or more search spaces connected to the CORESET.

[0199] The above-described PDCCH beam allocation method has a problem in that it is difficult to instruct a beam change faster than the MAC CE signaling delay, and also has a disadvantage in that the same beam is applied to all CORESETs regardless of the search space characteristics, which makes flexible PDCCH beam operation difficult. The following embodiments of the present disclosure provide a more flexible PDCCH beam setting and operation method. In describing the embodiments of the present disclosure below, several distinct examples are provided for the convenience of explanation, but these are not mutually exclusive and can be applied in appropriate combination depending on the situation.

[0200] A base station can set one or more TCI states for a specific control resource set to a terminal, and can 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 can transmit a command to the terminal to activate TCI state#0 for control resource set #1 through MAC CE. Based on the activation command for the TCI state received through MAC CE, the terminal can correctly receive DMRS of the corresponding control resource set based on QCL information in the activated TCI state.

[0201] 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, the terminal can assume that the DMRS transmitted in control resource set #0 has been QCL'd with the SS / PBCH block identified during the initial access process or the non-contention-based random access process that is not triggered by a PDCCH command.

[0202] For a control resource set (control resource set #X) whose index is set to a value other than 0, if the terminal has not set a TCI state for the control resource set #X, or has set one or more TCI states but has not received a MAC CE activation command to activate one of them, the terminal may assume that the DMRS transmitted in the control resource set #X is QCL'd with the SS / PBCH block identified during the initial access process.

[0203] Next, we will specifically explain downlink control information (DCI) in the 5G system.

[0204] 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 a DCI format for fallback and a DCI format for non-fallback for the PUSCH or PDSCH. The fallback DCI format can be composed of fixed fields defined between the base station and the terminal, and the non-fallback DCI format can include configurable fields.

[0205] DCI can be transmitted through the Physical Downlink Control Channel (PDCCH) after going through the channel coding and modulation process. A Cyclic Redundancy Check (CRC) is attached to the DCI message payload, and the CRC can be scrambled with a Radio Network Temporary Identifier (RNTI) corresponding to the identity of the UE. Different RNTIs can be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control command, or random access response. That is, the RNTI is not transmitted explicitly, but is included in the CRC calculation process. When the UE receives a DCI message transmitted on the PDCCH, it verifies the CRC using the assigned RNTI. If the CRC verification result is correct, the UE can determine that the message was transmitted to the UE.

[0206] For example, a DCI scheduling a PDSCH for System Information (SI) may be scrambled with SI-RNTI. A DCI scheduling a PDSCH for a Random Access Response (RAR) message may be scrambled with RA-RNTI. A DCI scheduling a PDSCH for a Paging message may be scrambled with P-RNTI. A DCI notifying a Slot Format Indicator (SFI) may be scrambled with SFI-RNTI. A DCI notifying a Transmit Power Control (TPC) may be scrambled with TPC-RNTI. A DCI scheduling a UE-specific PDSCH or PUSCH may be scrambled with C-RNTI (Cell RNTI).

[0207] DCI format 0_0 can be used as a fallback 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 can include the following information, for example, as shown in Table 11.

[0208]

[0209]

[0210] DCI format 0_1 ​​can be used as a fallback DCI for scheduling PUSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 0_1 ​​with the CRC scrambled with C-RNTI can include the following information, for example, as shown in Table 12.

[0211]

[0212]

[0213]

[0214]

[0215]

[0216]

[0217]

[0218] DCI format 1_0 can be used as a fallback 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 can include the following information, for example, as shown in Table 13.

[0219]

[0220]

[0221] DCI format 1_1 can be used as a fallback DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_1 with the CRC scrambled with C-RNTI can include the following information, for example, as shown in Table 14.

[0222]

[0223]

[0224]

[0225]

[0226]

[0227] Below, a time domain resource allocation method for a data channel in a 5G communication system is described.

[0228] The base station can set up a table for time domain resource allocation information for the downlink data channel (Physical Downlink Shared Channel; PDSCH) and the uplink data channel (Physical Uplink Shared Channel; PUSCH) to the terminal through higher layer signaling (e.g., RRC signaling). For the PDSCH, a table consisting of up to maxNrofDL-Allocations=16 entries can be set up, and for the PUSCH, a table consisting of up to maxNrofUL-Allocations=16 entries can be set up. For example, the time domain resource allocation information may include PDCCH-to-PDSCH slot timing (the time interval in slot units between the time point at which a PDCCH is received and the time point at which a PDSCH scheduled by the received PDCCH is transmitted, denoted as K0) or PDCCH-to-PUSCH slot timing (the time interval in slot units between the time point at which a PDCCH is received and the time point at which a PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), information on the position and length of the start symbol for which a PDSCH or PUSCH is scheduled within a slot, the mapping type of the PDSCH or PUSCH, etc. For example, information such as those in Tables 15 and 16 below may be notified from the base station to the terminal.

[0229]

[0230]

[0231] The base station can notify the terminal of one of the entries in the table for the above time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., by indicating it with the 'Time Domain Resource Allocation' field in the DCI). The terminal can obtain time domain resource allocation information for the PDSCH or PUSCH based on the DCI received from the base station.

[0232] Below, a method for allocating frequency domain resources for data channels in a 5G communication system is described.

[0233] In 5G, two types of methods for indicating frequency domain resource allocation information for downlink data channels (Physical Downlink Shared Channel; PDSCH) and uplink data channels (Physical Uplink Shared Channel; PUSCH) are supported: Resource Allocation Type 0 and Resource Allocation Type 1.

[0234] Resource Allocation Type 0

[0235] RB allocation information can be notified from the base station to the terminal in the form of a bitmap for an RBG (Resource Block Group). At this time, the RBG can be composed of a set of consecutive VRBs (Virtual RBs), and the size P of the RBG can be determined based on a value set as a higher layer parameter (rbg-Size) and the size value of the bandwidth part defined in Table 17 below.

[0236] Bandwidth Part SizeConfiguration 1Configuration 21 - 362437 - 724873 - 144816145 - 2751616

[0237] - Size The total number of RBGs in bandwidth part i (N RBG ) can be defined as follows.

[0238] ■ N RBG = , where

[0239] ◆ the size of the first RBG is ,

[0240] ◆ the size of the last RBG is , if >0 and P otherwise,

[0241] ◆ the size of all other RBGs is P.

[0242] - N RBG Each bit in the bitmap of bit size can correspond to each RBG. RBGs can be indexed in order of increasing frequency starting from the lowest frequency position in the bandwidth part. N within the bandwidth part RBG For the RBGs of the dog, from RBG#0 to RBG#(N RBG -1) can be mapped from MSB to LSB of the RBG bitmap. If a specific bit value in the bitmap is 1, the terminal can determine that the RBG corresponding to the bit value is allocated, and if a specific bit value in the bitmap is 0, the terminal can determine that the RBG corresponding to the bit value is not allocated.

[0243] Resource Allocation Type 1

[0244] - RB allocation information can be notified from the base station to the terminal as information on the start position and length of consecutively allocated VRBs. At this time, interleaving or non-interleaving can be additionally applied to consecutively allocated VRBs. The resource allocation field of resource allocation type 1 can be composed of a resource indication value (RIV), and the RIV can be the starting point of the VRB (RB start ) and the length of the consecutively allocated RB (L RBs ) can be composed of. More specifically, RIV within the bandwidth part of the size can be defined as follows.

[0245] ■ if (L RBs -1)≤ then

[0246] ◆ RIV =

[0247] ■ else

[0248] ◆ RIV =

[0249] ■ where L RBs ≥1 and shall not exceed -RB start.

[0250] For the purpose of supporting non-grant-based transmission and reception for a downlink data channel (Physical Downlink Shared Channel; PDSCH) or an uplink data channel (Physical Uplink Shared Channel; PUSCH) to a terminal, a base station can semi-statically set time and frequency transmission resources and various transmission and reception parameters for PDSCH and PUSCH.

[0251] To be more specific, it is as follows:

[0252] For the purpose of supporting downlink (DL) SPS (Semi-Persistent Scheduling) to a terminal, the base station can set the following information as shown in Table 18 through upper layer signaling (e.g. RRC signaling).

[0253]

[0254] DL SPS can be set in a primary cell or a secondary cell, and DL SPS can be set in one cell within one cell group.

[0255] In 5G, two types of non-grant (named as Configured Grant, Grant free, etc.)-based transmission methods for uplink data channels (Physical Uplink Shared Channel; PUSCH) can be supported: Type-1 non-grant-based PUSCH transmission with a configured grant and Type-2 non-grant-based PUSCH transmission with a configured grant.

[0256] Non-acknowledgement-based PUSCH transmission type-1

[0257] In non-grant-based PUSCH transmission type-1, the base station can configure specific time / frequency resources that allow non-grant-based PUSCH transmission to the terminal through higher layer signaling, such as RRC signaling. For example, time-domain allocation information, frequency-domain allocation information, and period information for the resources can be configured. In addition, the base station can configure various parameters for PUSCH transmission to the terminal through higher layer signaling, such as frequency hopping, DMRS configuration, MCS table, MCS, RBG (Resource Block Group) size, number of repetition transmissions, RV (Redundancy Version), etc. More specifically, the configuration information of Table 19 below can be included.

[0258]

[0259]

[0260] When the UE receives configuration information for non-grant-based PUSCH transmission type 1 from the base station, the UE can periodically transmit PUSCH using the configured resources without the base station's approval. Various parameters required for PUSCH transmission (e.g., frequency hopping, DMRS configuration, MCS, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), precoding and number of layers, antenna ports, frequency hopping offset, etc.) can all follow the configuration values ​​notified by the base station.

[0261] Non-acknowledgement-based PUSCH transmission type-2

[0262] In non-grant-based PUSCH transmission type 2, the base station can configure some of the information (e.g., period information, etc.) regarding specific time / frequency resources that allow non-grant-based PUSCH transmission to the UE through higher-layer signaling (e.g., RRC signaling). In addition, the base station can configure various parameters for PUSCH transmission to the UE through higher-layer signaling (e.g., frequency hopping, DMRS configuration, MCS table, RBG (Resource Block Group) size, number of repetitions, RV (Redundancy Version), etc.). More specifically, the base station can configure the configuration information in Table 20 below to the UE through higher-layer signaling.

[0263]

[0264] A base station may transmit a DCI composed of specific DCI field values ​​to a terminal for the purpose of scheduling activation or scheduling release for DL ​​SPS and UL grant Type 2.

[0265] To be more specific, it is as follows:

[0266] The base station can set a Configured Scheduling-RNTI (CS-RNTI) for the terminal, and the terminal can monitor the DCI format in which the CRC is scrambled with the CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with the CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 21 below, the terminal can regard the DCI as a command to activate transmission and reception for DL ​​SPS or UL grant Type 2.

[0267] DCI format 0_0 / 0_1DCI format 1_0DCI format 1_1HARQ process numbersset to all '0'sset to all '0'sset to all '0'sRedundancy versionset to '00'set to '00'For the enabled transport block: set to '00'

[0268] The base station can set a Configured Scheduling-RNTI (CS-RNTI) for the terminal, and the terminal can monitor the DCI format in which the CRC is scrambled with the CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with the CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 22 below, the terminal can regard the DCI as a command to release transmission and reception for DL ​​SPS or UL grant Type 2.

[0269] DCI format 0_0DCI format 1_0HARQ process numbersset to all '0'sset to all '0'sRedundancy versionset to '00'set to '00'Modulation and coding schemeset to all '1'sset to all '1'sFrequency domain resource assignmentset to all '1'sset to all '1's

[0270] The DCI indicating a 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 UE must always monitor the PDCCH in a cell in which the DL SPS or UL grant Type 2 is configured 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 configured for cross-carrier scheduling, the UE must always monitor the DCI format 1_0 or DCI format 0_0 in the cell in order to receive a release command for the DL SPS or UL grant Type 2 configured for the cell.

[0271] Below, carrier aggregation and scheduling methods in 5G communication systems are described in detail.

[0272] A terminal can be configured with multiple cells (Cells or CCs (Component Carriers)) from a base station, and can be configured with whether to perform cross-carrier scheduling for the cells configured in the terminal. If cross-carrier scheduling is configured for a specific cell (Cell A, Scheduled Cell), PDCCH monitoring for Cell A may not be performed in Cell A, but may be performed in another cell indicated by cross-carrier scheduling (Cell B, Scheduling Cell). In this case, the scheduled cell (Cell A) and the scheduling cell (Cell B) may be configured with different numerologies. Here, the numerologies may include subcarrier spacing, cyclic prefix, etc. When the numerologies of Cell A and Cell B are different, when the PDCCH of Cell B schedules the PDSCH of Cell A, the following minimum scheduling offset may be additionally considered between the PDCCH and the PDSCH.

[0273] Cross-carrier scheduling method

[0274] ◆ Subcarrier spacing of cell B (μ) B ) is the subcarrier spacing (μ) of cell A. A ) is less than, the PDSCH can be scheduled from the next PDSCH slot corresponding to X symbols after the last symbol of the PDCCH received from cell B. Here, X is μ B It may vary depending on μ B When =15kHz, X=4 symbols, μ B When =30kHz, X=4 symbols,μ B When =60kHz, it can be defined as X=8 symbols.

[0275] ◆ Subcarrier spacing of cell B (μ) B ) is the subcarrier spacing (μ) of cell A. A) is greater than, the PDSCH can be scheduled from the point in time corresponding to X symbols after the last symbol of the PDCCH received from cell B. Here, X is μ B It may vary depending on μ B When =30kHz, X=4 symbols, μ B When =60kHz, X=8 symbols,μ B When =120kHz, it can be defined as X=12 symbols.

[0276] Below, the rate matching operation and puncturing operation are described in detail.

[0277] When a time and frequency resource A, through which an arbitrary symbol sequence A is to be transmitted, overlaps with an arbitrary time and frequency resource B, a rate matching or puncturing operation may be considered for transmission and reception operations of channel A considering resource C, an area in which resources A and B overlap. The specific operations may follow the contents below.

[0278] Rate Matching Operation

[0279] - The base station can map and transmit channel A only for the remaining resource areas excluding resource C corresponding to the overlapping area with resource B among the entire resources A that want to transmit symbol sequence A to the terminal. For example, if symbol sequence A is composed 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 sequentially map and transmit symbol sequence A to {resource #1, resource #2, resource #4}, which are the remaining resources among resource A excluding {resource #3} corresponding to resource C. As a result, the base station can map and transmit symbol sequences {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4}, respectively.

[0280] The terminal can determine resources A and B from scheduling information for symbol sequence A from the base station, and can thereby determine resource C, which is an area where resources A and B overlap. The terminal can receive symbol sequence A, assuming that symbol sequence A was mapped and transmitted in the remaining area of ​​the entire resource A except for resource C. For example, if symbol sequence A is composed of {symbol #1, symbol #2, symbol #3, symbol #4}, and 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, assuming that it was sequentially mapped to {resource #1, resource #2, resource #4}, which are the remaining resources among resource A except for {resource #3}, which corresponds to resource C. As a result, the terminal can perform a series of subsequent reception operations, assuming that symbol sequences {symbol #1, symbol #2, symbol #3} were mapped and transmitted to {resource #1, resource #2, resource #4}, respectively.

[0281] Puncture action

[0282] If a base station wants to transmit symbol sequence A to a terminal, and there is a resource C corresponding to an area overlapping with resource B among all resources A, 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 for the remaining resource areas of resource A excluding resource C. For example, if symbol sequence A is composed 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}, and 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 among resources A, and may not transmit {symbol #3} mapped to {resource #3} corresponding to resource C. As a result, the base station can transmit symbol sequences {symbol #1, symbol #2, symbol #4} by mapping them to {resource #1, resource #2, resource #4}, respectively.

[0283] The terminal can determine resources A and B from scheduling information for symbol sequence A from the base station, and can thereby determine resource C, which is an area where resources A and B overlap. The terminal can receive symbol sequence A assuming that symbol sequence A is mapped to the entire resource A, but is transmitted only in the remaining area of ​​resource area A excluding resource C. For example, if symbol sequence A is composed 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 it assuming that symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to {resource #1, resource #2, resource #4}, which are the remaining resources among resource A except {resource #3} corresponding to resource C, are mapped and transmitted. As a result, the terminal can assume that the symbol sequence {symbol #1, symbol #2, symbol #4} is transmitted by being mapped to {resource #1, resource #2, resource #4}, respectively, and perform a series of subsequent receiving operations.

[0284] FIG. 10 is a diagram for explaining a method for a base station and a terminal to transmit and receive data by taking into account downlink data channels and rate matching resources according to one embodiment of the present disclosure.

[0285] Referring to FIG. 10, a downlink data channel (PDSCH, 1001) and a rate matching resource (1002) are illustrated. A base station can configure one or more rate matching resources (1002) to a terminal through upper layer signaling (e.g., RRC signaling). The rate matching resource (1002) configuration information may include time-domain resource allocation information (1003), frequency-domain resource allocation information (1004), and period information (1005). In the following, the bitmap corresponding to the frequency-domain resource allocation information (1004) is named "the first bitmap", the bitmap corresponding to the time-domain resource allocation information (1003) is named "the second bitmap", and the bitmap corresponding to the period information (1005) is named "the third bitmap". When all or part of the time and frequency resources of a scheduled data channel (1001) overlap with the set rate matching resources (1002), the base station can rate-match and transmit the data channel (1001) 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.

[0286] The base station can dynamically notify the terminal via DCI whether to rate-match the data channel in the set rate-matching resource portion through additional configuration (corresponding to the "rate-matching indicator" in the aforementioned DCI format). Specifically, the base station can select some of the set rate-matching resources and group them into rate-matching resource groups, and can use a bitmap to indicate to the terminal via DCI whether the data channel for each rate-matching resource group is rate-matched. 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}, RMG#2={RMR#3, RMR#4} as the rate-matching groups, and can use two bits in the DCI field to indicate to the terminal whether to rate-match in RMG#1 and RMG#2, respectively, using a bitmap. For example, the base station can instruct the terminal to perform rate matching by indicating "1" when rate matching is required, and to not perform rate matching by indicating "0" when rate matching is not required.

[0287] 5G supports granularity at the "RB symbol level" and "RE level" by setting the aforementioned rate matching resources on the terminal. More specifically, the following setting method can be followed.

[0288] RB symbol level

[0289] A terminal can receive up to four RateMatchPatterns per bandwidth part through upper layer signaling, and one RateMatchPattern can include the following contents.

[0290] - As a reserved resource within the bandwidth part, a resource in which the time and frequency resource domains of the reserved resource are set by combining a bitmap at the RB level and a bitmap at the symbol level along the frequency axis may be included. The reserved resource may span 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 additionally be set.

[0291] - The bandwidth part may include a time and frequency domain resource area set as a control resource set and a resource area corresponding to a time domain pattern set as a search space setting in which the resource area is repeated.

[0292] RE level

[0293] The terminal can be configured with the following contents through upper layer signaling.

[0294] - The configuration information (lte-CRS-ToMatchAround) for RE corresponding to the LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern may include the number of LTE CRS ports (nrofCRS-Ports) and the LTE-CRS-vshift(s) value (v-shift), the location information (carrierFreqDL) of the center subcarrier of the LTE carrier from the reference frequency point (e.g., reference point A), the bandwidth size (carrierBandwidthDL) information of the LTE carrier, and the subframe configuration information (mbsfn-SubframConfigList) corresponding to the MBSFN (Multicast-broadcast single-frequency network). Based on the above-described information, the terminal can determine the location of the CRS within the NR slot corresponding to the LTE subframe.

[0295] - It may contain configuration information for a set of resources corresponding to one or more ZP (Zero Power) CSI-RSs within the bandwidth part.

[0296] Below, we will specifically describe a method for measuring and reporting channel status in a 5G communication system.

[0297] Channel state information (CSI) may include a channel quality indicator (CQI), a precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), an SS / PBCH block resource indicator (SSBRI), a layer indicator (LI), a 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.

[0298] For the aforementioned CSI measurement and reporting, the terminal may receive setting information (CSI-ReportConfig) for N (≥1) CSI reports, setting information (CSI-ResourceConfig) for M (≥1) RS transmission resources, and one or two trigger state lists (CSI-AperiodicTriggerStateList, CSI-SemiPersistentOnPUSCH-TriggerStateList) through upper layer signaling.

[0299] The setup information for the aforementioned CSI measurement and reporting may be as described more specifically in Tables 23-1 to 29 below.

[0300] [Table 23-1]

[0301]

[0302]

[0303]

[0304]

[0305]

[0306] [Table 23-2]

[0307]

[0308]

[0309] [Table 24-1]

[0310]

[0311] [Table 24-2]

[0312]

[0313] [Table 25-1]

[0314]

[0315] [Table 25-2]

[0316]

[0317]

[0318] [Table 27-1]

[0319]

[0320] [Table 27-2]

[0321]

[0322] [Table 28-1]

[0323]

[0324] [Table 28-2]

[0325]

[0326]

[0327]

[0328] For the aforementioned CSI report setting (CSI-ReportConfig), each report setting CSI-ReportConfig can be associated with one downlink (DL) bandwidth part identified by the upper layer parameter bandwidth part identifier (bwp-id) given by the CSI resource setting, CSI-ResourceConfig, associated with the corresponding report setting. For the time domain reporting operation for each report setting CSI-ReportConfig, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, which can be configured from the base station to the terminal by the reportConfigType parameter configured from the upper layer. The semi-persistent CSI reporting method supports 'PUCCH-based semi-persistent (semi-PersistentOnPUCCH)' and 'PUSCH-based semi-persistent (semi-PersistentOnPUSCH)'. For periodic or semi-permanent CSI reporting methods, the UE can receive PUCCH or PUSCH resources for transmitting CSI from the base station through higher-layer signaling. The period and slot offset of the PUCCH or PUSCH resources for transmitting CSI can be given as numerology of the uplink (UL) bandwidth portion configured for CSI report transmission. For aperiodic CSI reporting methods, the UE can receive scheduling of PUSCH resources for transmitting CSI from the base station through L1 signaling (the aforementioned DCI format 0_1).

[0329] For the aforementioned CSI resource setting (CSI-ResourceConfig), each CSI resource setting CSI-ReportConfig can include S (≥1) CSI resource sets (given by the upper layer parameter csi-RS-ResourceSetList). The CSI resource set list can be composed of a non-zero power (NZP) CSI-RS resource set and a SS / PBCH block set, or a CSI-interference measurement (CSI-IM) resource set. Each CSI resource setting can be located in a downlink (DL) bandwidth segment identified by the upper layer parameter bwp-id, and the CSI resource setting can be linked to a CSI reporting setting in the same downlink bandwidth segment. The time domain operation of the CSI-RS resources within the CSI resource setting can be set to one of 'aperiodic', 'periodic', or 'semi-persistent' from the upper layer parameter resourceType. For periodic or semi-permanent CSI resource settings, the number of CSI-RS resource sets can be limited to S=1, and the configured period and slot offset can be given as a numerology of a downlink bandwidth portion identified by bwp-id. A terminal can receive one or more CSI resource settings for channel or interference measurement from a base station through higher layer signaling, and may include, for example, the following CSI resources.

[0330] - CSI-IM resources for interference measurements

[0331] - NZP CSI-RS resources for interference measurements

[0332] - NZP CSI-RS resources for channel measurements

[0333] For CSI-RS resource sets associated with resource settings where the upper layer parameter resourceType is set to 'aperiodic', 'periodic', or 'semi-persistent', the trigger state for the CSI report setting where reportType is set to 'aperiodic' and the resource settings for channel or interference measurements for one or more component cells (CC) can be set with the upper layer parameter CSI-AperiodicTriggerStateList.

[0334] Aperiodic CSI reporting of a terminal can utilize PUSCH, periodic CSI reporting can utilize PUCCH, and semi-persistent CSI reporting can be performed using PUSCH when triggered or activated by DCI, or PUCCH after activation by MAC control element (MAC CE). As mentioned above, CSI resource settings can also be configured as aperiodic, periodic, or semi-persistent. Combinations between CSI reporting settings and CSI resource settings can be supported based on Table 30 below.

[0335] CSI-RS ConfigurationPeriodic CSI ReportingSemi-Persistent CSI ReportingAperiodic CSI ReportingPeriodic CSI-RSNo dynamic triggering / activationFor reporting on PUCCH, the UE receives an activation command [10, TS 38.321]; for reporting on PUSCH, the UE receives triggering on DCITriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.Semi-Persistent CSI-RSNot SupportedFor reporting on PUCCH, the UE receives an activation command [10, TS 38.321]; for reporting on PUSCH, the UE receives triggering on DCITriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.Aperiodic CSI-RSNot SupportedNot SupportedTriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.

[0336] Aperiodic CSI reporting can be triggered by the "CSI request" field of the aforementioned DCI format 0_1 ​​corresponding to the scheduling DCI for the PUSCH. The UE can monitor the PDCCH, acquire the DCI format 0_1, and acquire scheduling information and a CSI request indicator for the PUSCH. The CSI request indicator is N TS (=0, 1, 2, 3, 4, 5, or 6) bits and can be determined by higher layer signaling (reportTriggerSize). One or more aperiodic CSI reporting trigger states that can be set by higher layer signaling (CSI-AperiodicTriggerStateList) can be triggered by the CSI request indicator.

[0337] - If all bits in the CSI request field are 0, this may mean that no CSI report is requested.

[0338] - If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is greater than 2NTs-1, M CSI trigger states can be mapped to 2NTs-1 according to the mapping relationship defined, and one of the trigger states of 2NTs-1 can be indicated by the CSI request field.

[0339] - 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 can be indicated by the CSI request field.

[0340] Table 31 below shows an example of the relationship between a CSI request indicator and the CSI trigger state that can be indicated by the indicator.

[0341] CSI request fieldCSI trigger stateCSI-ReportConfigIdCSI-ResourceConfigId00no CSI requestN / AN / A01CSI trigger state#1CSI report#1CSI resource#1,CSI report#2CSI resource#210CSI trigger state#2CSI report#3CSI resource#311CSI trigger state#3CSI report#4CSI resource#4

[0342] A terminal may perform measurement on a CSI resource within a CSI trigger state triggered by a CSI request field, and may generate CSI (including at least one of the aforementioned CQI, PMI, CRI, SSBRI, LI, RI, or L1-RSRP) therefrom. The terminal may transmit the acquired CSI using a PUSCH scheduled by the corresponding DCI format 0_1. When 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in the DCI format 0_1 ​​indicates "1", the terminal may multiplex and transmit the acquired CSI with uplink data (UL-SCH) on the PUSCH resource scheduled by the DCI format 0_1. When 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "0", the terminal can transmit only CSI without uplink data (UL-SCH) by mapping it to the PUSCH resource scheduled by DCI format 0_1.

[0343] FIGS. 11 and 12 illustrate aperiodic CSI reporting methods when the CSI-RS offset is 0 according to an embodiment of the present disclosure.

[0344] Referring to FIG. 11, the terminal can monitor the PDCCH (1101) to obtain DCI format 0_1, from which it can obtain scheduling information and CSI request information for the PUSCH (1105). The terminal can obtain resource information for the CSI-RS (1102) to be measured from the received CSI request indicator. The terminal can determine when to perform measurement on the transmitted CSI-RS (1102) resource based on the time point of receiving DCI format 0_1 ​​and the parameter (aperiodicTriggeringOffset described above) for the offset in the CSI resource set configuration (e.g., NZP CSI-RS resource set configuration (NZP-CSI-RS-ResourceSet)). More specifically, the terminal can receive an offset value X of the parameter aperiodicTriggeringOffset in the NZP-CSI-RS resource set configuration from the base station through upper layer signaling, and the set offset value X can mean an offset (1103) between a slot in which a DCI that triggers aperiodic CSI reporting is received and a slot in which a CSI-RS resource is transmitted. For example, the aperiodicTriggeringOffset parameter value and the offset value X can have a mapping relationship described in Table 32 below.

[0345] aperiodicTriggeringOffsetOffset X00 slot11 slot22 slots33 slots44 slots516 slots624 slots

[0346] Referring to FIG. 12, the aforementioned offset value may be set to X=0. In this case, the terminal may receive the CSI-RS (1202) in a slot (corresponding to slot 0 in FIG. 11) in which the DCI format 0_1 ​​that triggers the aperiodic CSI report is received, and may report the CSI information measured with the received CSI-RS to the base station via the PUSCH (1205). The terminal may obtain scheduling information (information corresponding to each field of the aforementioned DCI format 0_1) for the PUSCH (1205) for CSI reporting from the DCI format 0_1. For example, the terminal may obtain information on a slot in which the PUSCH (1205) is to be transmitted from the aforementioned time domain resource allocation information for the PUSCH (1205) in the DCI format 0_1. In an example of FIG. 11, the terminal acquires a K2 value corresponding to a slot offset value for PDCCH-to-PUSCH as 3, and accordingly, the PUSCH (1105) can be transmitted in slot 3 (1109), which is 3 slots away from slot 0 (1106), at the time when the PDCCH (1101) is received.

[0347] In an example of FIG. 12, the terminal can monitor the PDCCH (1201) to obtain DCI format 0_1, and can obtain scheduling information and CSI request information for the PUSCH (1205) from this. The terminal can obtain resource information for the CSI-RS (1202) to be measured from the received CSI request indicator. An example of FIG. 12 shows an example in which the offset value for the aforementioned CSI-RS is set to X=1. In this case, the terminal can receive the CSI-RS (1202) in a slot in which the DCI format 0_1 ​​that triggers aperiodic CSI reporting is received (corresponding to slot 0 (1206) of FIG. 13), and can report the CSI information measured with the received CSI-RS to the base station through the PUSCH (1205).

[0348] Next, we will specifically explain the bandwidth part (BWP) settings in the 5G communication system.

[0349] FIG. 13 illustrates settings for a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

[0350] Referring to FIG. 13, the UE bandwidth (1300) can be set to two bandwidth parts, namely, bandwidth part #1 (BWP#1) (1301) and bandwidth part #2 (BWP#2) (1302). The base station can set one or more bandwidth parts to the UE, and can set the following information for each bandwidth part, as shown in Table 33.

[0351]

[0352] The above information can be transmitted from the base station to the terminal via higher-layer signaling, such as RRC (Radio Resource Control) signaling. At least one bandwidth part among one or more configured bandwidth parts can be activated. Whether or not the configured bandwidth part is activated can be semi-statically transmitted from the base station to the terminal via RRC signaling or dynamically transmitted via DCI (Downlink Control Information).

[0353] Before RRC (Radio Resource Control) connection, a terminal can receive the initial bandwidth part (Initial BWP) for initial connection from the base station through MIB (Master Information Block). More specifically, during the initial connection phase, the terminal can receive configuration information about a control region (Control Resource Set, CORESET) and a search space where a PDCCH (Physical Downlink Control Channel) for receiving system information (Remaining System Information; which may correspond to RMSI or System Information Block 1; SIB1) required for initial connection can be transmitted through MIB. The control region and search space configured by MIB can each be regarded as identifier (Identity, ID) 0. The base station can notify the terminal of configuration information such as frequency allocation information, time allocation information, and numerology for control region #0 through MIB. Additionally, the base station can notify the terminal of the monitoring cycle and occasion settings for control area #0, i.e., search space #0, via the MIB. The terminal can consider the frequency range designated as control area #0, obtained from the MIB, as the initial bandwidth part for initial access. At this time, the identifier (ID) of the initial bandwidth part can be considered as 0.

[0354] The settings for the bandwidth part supported by the above 5G can be used for various purposes.

[0355] In one embodiment, when the bandwidth supported by a terminal is smaller than the system bandwidth, this can be supported through bandwidth part settings. For example, by setting the frequency location (setting information 2) of the bandwidth part to the terminal, the base station can enable the terminal to transmit and receive data at a specific frequency location within the system bandwidth.

[0356] To support different numerologies, a base station can configure multiple bandwidth parts for a terminal. For example, to support data transmission and reception using both 15 kHz and 30 kHz subcarrier spacing for a given terminal, two bandwidth parts can be configured with subcarrier spacings of 15 kHz and 30 kHz, respectively. These different bandwidth parts can be frequency-division multiplexed, and when data is to be transmitted or received using a specific subcarrier spacing, the bandwidth part configured for that subcarrier spacing can be activated.

[0357] Additionally, for the purpose of reducing power consumption of the terminal, the base station can configure bandwidth parts with different bandwidth sizes for the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and constantly transmits and receives data using that bandwidth, it can result in very high power consumption. In particular, monitoring unnecessary downlink control channels using a large bandwidth of 100 MHz in a traffic-free environment can be very inefficient in terms of power consumption. To reduce power consumption of the terminal, the base station can configure a bandwidth part with a relatively small bandwidth, such as 20 MHz, for the terminal. In a traffic-free environment, the terminal can perform monitoring operations using 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.

[0358] In the method for setting the bandwidth part, terminals prior to RRC connection can receive configuration information for the initial bandwidth part through the MIB (Master Information Block) during the initial access stage. More specifically, the terminal can receive a control region (Control Resource Set, CORESET) for a downlink control channel on which DCI (Downlink Control Information) for scheduling a SIB (System Information Block) can be transmitted from the MIB of the PBCH (Physical Broadcast Channel). The bandwidth of the control region set by the MIB can be regarded as the initial bandwidth part, and the terminal can receive the PDSCH (Physical Downlink Shared Channel) on which the SIB is transmitted through the set initial bandwidth part. In addition to receiving the SIB, the initial bandwidth part can also be utilized for other system information (Other System Information, OSI), paging, and random access.

[0359] When one or more bandwidth parts are set for a terminal, the base station can instruct the terminal to change the bandwidth part using the bandwidth part indicator field in the DCI. For example, referring to FIG. 13, when the currently activated bandwidth part of the terminal is bandwidth part #1 (1301), the base station can instruct the terminal to bandwidth part #2 (1302) using the bandwidth part indicator in the DCI, and the terminal can perform a bandwidth part change to bandwidth part #2 (1302) indicated by the bandwidth part indicator in the received DCI.

[0360] As described above, since DCI-based bandwidth part changes can be indicated by DCI scheduling PDSCH or PUSCH (Physical Uplink Shared Channel), when a UE receives a bandwidth part change request, it must be able to seamlessly receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI in the changed bandwidth part. To this end, the standard specifies requirements for the delay time (TBWP) required when changing the bandwidth part, which can be defined, for example, as shown in Table 34 below.

[0361]

[0362] The bandwidth part change delay time requirement supports Type 1 or Type 2 depending on the terminal's capabilities. The terminal can report the supported bandwidth part delay time type to the base station.

[0363] According to the requirement on the bandwidth part change delay time described above, when a terminal receives a DCI including 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 no 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 wants to schedule a data channel with the new bandwidth part, the base station can determine the time domain resource allocation for the data channel by considering the bandwidth part change delay time (TBWP) of the terminal. That is, when the base station schedules a data channel with the new bandwidth part, the data channel can be scheduled after the bandwidth part change delay time in the method of determining the time domain resource allocation for the data channel. Accordingly, the terminal may not expect that the DCI indicating the bandwidth part change indicates a slot offset (K0 or K2) value smaller than the bandwidth part change delay time (TBWP).

[0364] If the terminal receives DCI (e.g., DCI format 1_1 or 0_1) indicating a bandwidth part change, the terminal may not perform any transmission or reception during the time period corresponding to the third symbol of the slot in which the PDCCH including the DCI is received, to the start point of the slot indicated by the slot offset (K0 or K2) value indicated by the time domain resource allocation indicator field in the DCI. For example, if the terminal receives DCI indicating a bandwidth part change in slot n and the slot offset value indicated by the 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).

[0365] Next, we will explain how to set transmission and reception related parameters for each bandwidth part in 5G.

[0366] The terminal can be configured with one or more bandwidth parts from the base station, and can additionally be configured with parameters to be used for transmission and reception for each configured bandwidth part (e.g., configuration information related to uplink / downlink data channels and control channels, etc.). For example, referring to FIG. 13, if the terminal is configured with bandwidth part #1 (1301) and bandwidth part #2 (1302), the terminal can be configured with transmission / reception parameter #1 for bandwidth part #1 (1301), and can be configured with 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.

[0367] More specifically, the following parameters can be set from the base station to the terminal.

[0368] First, for the uplink bandwidth part, the information in Table 35 can be set.

[0369]

[0370]

[0371] According to [Table 35], the terminal can be configured with cell-specific (or cell common or common) transmission-related parameters (e.g., parameters related to a Random Access Channel (RACH), a Physical Uplink Control Channel (PUCCH), and a Physical Uplink Shared Channel)) from the base station (corresponding to BWP-UplinkCommon). In addition, the terminal can be configured with terminal-specific (or dedicated) transmission-related parameters (e.g., parameters related to a PUCCH, a PUSCH, a Configured Grant PUSCH, and a Sounding Reference Signal (SRS)) from the base station (corresponding to BWP-UplinkDedicated).

[0372] Next, for the downlink bandwidth part, the following information can be set as in Table 36.

[0373]

[0374] According to [Table 36], the terminal can be configured with cell-specific (or cell common or common) reception-related parameters (e.g., parameters related to a downlink control channel (PDCCH) and a downlink data channel (Physical Downlink Shared Channel)) from the base station (corresponding to BWP-DownlinkCommon). In addition, the terminal can be configured with terminal-specific (or dedicated) reception-related parameters (e.g., parameters related to a PDCCH, a PDSCH, a semi-persistent scheduled PDSCH, and radio link monitoring (RLM)) from the base station (corresponding to BWP-UplinkDedicated).

[0375] Below, we will specifically explain the DRX (Discontinuous Reception) settings in a 5G communication system.

[0376] FIG. 14 illustrates DRX (Discontinuous Reception) in a 5G communication system according to one embodiment of the present disclosure.

[0377] DRX is an operation in which a terminal using a service discontinuously receives data 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 turns on the receiver at a specific time to monitor the control channel, and if no data is received for a certain period of time, the receiver is turned off, reducing the terminal's power consumption. DRX operation can be controlled by the MAC layer device based on various parameters and timers.

[0378] Referring to Figure 14, Active time (1405) is the time when the terminal wakes up every DRX cycle and monitors the PDCCH. Active time (1405) can be defined as follows.

[0379] - drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer is running; or

[0380] - a Scheduling Request is sent on PUCCH and is pending; or

[0381] - 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

[0382] 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 the PDCCH when a certain condition is met.

[0383] drx-onDurationTimer(1415) is a parameter for setting the minimum time for which the terminal stays awake in the DRX cycle. drx-InactivityTimer(1420) is a parameter for setting the additional time for which the terminal stays awake when receiving (1430) a PDCCH indicating a new uplink transmission or downlink transmission. drx-RetransmissionTimerDL is a parameter for setting the maximum time for which the terminal stays awake to receive a downlink retransmission in a downlink HARQ procedure. drx-RetransmissionTimerUL is a parameter for setting the maximum time for which the terminal stays awake to receive an uplink retransmission grant in an uplink HARQ procedure. drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, and drx-RetransmissionTimerUL can be set as, for example, time, the number of subframes, the number of slots, etc. ra-ContentionResolutionTimer is a parameter for monitoring PDCCH in random access procedure.

[0384] The inActive time (1410) is a time set not to monitor PDCCH during DRX operation and / or a time set not to receive PDCCH. The remaining time excluding the Active time (1405) from the entire time of performing the DRX operation can be the inActive time (1410). If the terminal does not monitor the PDCCH during the Active time (1405), it can enter a sleep or inActive state to reduce power consumption.

[0385] DRX cycle refers to the period during which the terminal wakes up and monitors the PDCCH. In other words, it refers to the time interval or on duration that occurs after the terminal monitors the PDCCH until it monitors the next PDCCH. There are two types of DRX cycles: short DRX cycle and long DRX cycle. Short DRX cycle can be applied optionally.

[0386] Long DRX cycle (1425) is the longer cycle among the two DRX cycles set in the terminal. While operating in Long DRX, the terminal starts drx-onDurationTimer (1415) again at a point in time when Long DRX cycle (1425) has elapsed from the starting point (e.g., start symbol) of drx-onDurationTimer (1415). When operating in Long DRX cycle (1425), the terminal can start drx-onDurationTimer (1415) in a slot after drx-SlotOffset in a subframe satisfying [Mathematical Formula 2] below. Here, drx-SlotOffset means a delay before starting drx-onDurationTimer (1415). drx-SlotOffset can be set to, for example, time, the number of slots, etc.

[0387] [Equation 2]

[0388] [(SFN × 10) + subframe number] modulo (drx-LongCycle) = drx-StartOffset

[0389] At this time, drx-LongCycleStartOffset can include Long DRX cycle (1525) and drx-StartOffset, and can be used to define a subframe to start Long DRX cycle (1425). For example, drx-LongCycleStartOffset can be set to time, number of subframes, number of slots, etc.

[0390] A Short DRX cycle is a shorter cycle among the two DRX cycles defined in a terminal. The terminal operates in a Long DRX cycle (1425), and when a certain event occurs during the Active time (1405), for example, when a PDCCH indicating a new uplink transmission or downlink transmission is received (1430), the terminal starts or restarts the drx-InactivityTimer (1420), and if the drx-InactivityTimer (1420) expires or a DRX command MAC CE is received, the terminal may operate in a short DRX cycle. For example, in FIG. 14, the terminal starts the drx-ShortCycleTimer at the time when the previous drx-onDurationTimer (1415) or drx-InactivityTimer (1420) expires, and may operate in a short DRX cycle until the drx-ShortCycleTimer expires. When the terminal receives (1430) a PDCCH indicating a new uplink transmission or downlink transmission, the terminal 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 operating in short DRX, the terminal starts drx-onDurationTimer (1415) again when the short DRX cycle has elapsed from the start point of the previous on duration. After that, when drx-ShortCycleTimer expires, the terminal operates in the Long DRX cycle (1425) again.

[0391] When operating in a short DRX cycle, the terminal can start drx-onDurationTimer (1415) after drx-SlotOffset in a subframe satisfying [Mathematical Formula 3] below. Here, drx-SlotOffset refers to a delay before starting drx-onDurationTimer (1415). For example, drx-SlotOffset can be set to time, number of slots, etc.

[0392] [Equation 3]

[0393] [(SFN × 10) + subframe number] modulo (drx-ShortCycle) = (drx-StartOffset) modulo (drx-ShortCycle)

[0394] Here, drx-ShortCycle and drx-StartOffset can be used to define the subframe at which the Short DRX cycle will start. drx-ShortCycle and drx-StartOffset can be set to, for example, time, number of subframes, number of slots, etc.

[0395] The DRX operation has been described with reference to FIG. 14 so far. According to one embodiment, the terminal can reduce its power consumption by performing the DRX operation. However, even if the terminal performs the DRX operation, the terminal does not always receive the PDCCH related to the terminal during the Active Time (1405). Therefore, in one embodiment of the present disclosure, a signal for controlling the operation of the terminal can be provided to more efficiently save the power of the terminal.

[0396] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed during initial access. In addition to the actions performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following processes:

[0397] - Storage of AS (Access stratum) information required for cell connection

[0398] - Terminal-specific DRX cycle operation set by the RRC layer

[0399] - Setting up and periodically updating RNA (RAN (radio access network)-based notification area) that can be utilized during handover by the RRC layer

[0400] - Monitoring of RAN-based paging messages transmitted via I-RNTI (inactive-radio network temporary identifier)

[0401] A terminal in RRC_CONNECTED state can change from RRC_CONNECTED to RRC_INACTIVE or RRC_IDLE state by receiving an RRC Release instruction from the base station.

[0402] A terminal in RRC_INACITVE or RRC_IDLE state can change from RRC_INACTIVE or RRC_IDLE to RRC_CONNECTED state by performing random access and completing all random access procedures.

[0403] Below, a scheduling method for a base station to transmit downlink data to a terminal or instruct the terminal to transmit uplink data is described.

[0404] Downlink Control Information (DCI) may be control information transmitted from 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 given terminal. Typically, the base station independently performs channel coding on DCI for each terminal and then transmits it to each terminal via the Physical Downlink Control Channel (PDCCH).

[0405] The base station can operate by applying a DCI format determined for the purpose of scheduling, such as whether it is scheduling information for downlink data (downlink assignment), scheduling information for uplink data (uplink grant), or DCI for power control.

[0406] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), a physical channel for downlink data transmission. The base station can inform the terminal of scheduling information such as the specific mapping location in the time and frequency domain of the PDSCH, modulation method, HARQ-related control information, and power control information through DCI related to downlink data scheduling information among the DCI transmitted via the PDCCH.

[0407] A terminal can transmit uplink data to a base station via the Physical Uplink Shared Channel (PUSCH), a physical channel for uplink data transmission. The base station can inform the terminal of 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 DCI related to uplink data scheduling information among the DCI transmitted via the PDCCH.

[0408] For RRC_IDLE / RRC_INACTIVE terminals, the above-mentioned DRX operation is performed and a paging message is received. The terminal can monitor one paging occasion (PO) during a DRX cycle. A 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 may be transmitted and received. A paging frame (PF) may be one radio frame (10 ms) and may include one or multiple POs or starting points (e.g., offsets) of POs.

[0409] PF and PO can be determined by the following formulas:

[0410] The SFN (System Frame Number) for PF can be determined by (SFN + PF_offset) mod T = (T div N)*(UE_ID mod N), where PF_offset is an offset for PF determination, T is a DRX cycle, N is the number of PFs per DRX cycle (e.g., cell common, cell specific), which can be determined by higher-level signals such as system information, and UE_ID is a terminal ID (e.g., 5G-S-TMSI), which can be determined by the core network.

[0411] The PFs determined by N may refer to paging frames commonly applied to terminals within a cell, and may be referred to as cell common PFs for convenience hereinafter.

[0412] i_s, which indicates the PO index, can be determined by i_s = floor (UE_ID / N) mod Ns, where Ns can mean the number of POs in one PF and can be determined by a higher-order signal such as system information.

[0413] For example, if PF_offset=3, T=128, N=T / 4=32, Ns=4, and UE_ID mod 32 is 1, and floor (UE_ID / 32) mod 4 is 1, then the values ​​of the parameters can be determined by the following formula.

[0414] (SFN + 3) mod 128 = (128 div 32)*(UE_ID mod 32) = 4*1 = 4,

[0415] i_s = floor (UE_ID / 32) mod 4 = 1

[0416] Accordingly, the PF, which is a paging frame that a terminal with the above UE_ID must receive, can be determined as a radio frame with SFN of 1, 129, 257, ... among the common PFs of the cell, and the PO can be determined as the (i_s + 1)th PO among the four POs in the PF.

[0417] Hereinafter, the reception of PEI (Paging Early Indication) is described in more detail. In order to reduce terminal power consumption while monitoring and receiving the paging control channel and paging data channel in each DRX cycle, the terminal can receive PEI.

[0418] According to various embodiments of the present disclosure, a terminal may monitor or receive one PEI Occasion (PEI-O) before receiving paging during a DRX cycle. When the terminal receives a PEI and the PEI indicates a subgroup to which the terminal belongs and a paging okay, the terminal belonging to the subgroup may monitor the associated paging okay (PO). If the terminal does not detect the PEI in the PEI okay or the PEI does not indicate a subgroup to which the terminal belongs and a paging okay, the terminal does not need to monitor the associated paging okay (PO), thereby reducing terminal power consumption.

[0419] The terminal can determine PEI occupancy as follows. The PEI occupancy can be set to a subframe offset behind the radio frame of the reference point that is located ahead of the PF containing the associated PO by pei-FrameOffset. The terminal can monitor PEI in the PEI occupancy determined by the above method. Here, pei-FrameOffset, subframe offset, etc. can be determined by higher-level signals such as system information.

[0420] For convenience in the following description of the present disclosure, cells, transmission points, panels, beams, and / or transmission directions, which 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 uniformly described as TRP (transmission reception point), beam, or TCI state. Therefore, when actually applying the present disclosure, TRP, beam, or TCI state may be appropriately replaced with one of the above terms.

[0421] Hereinafter, embodiments of the present disclosure will be described using a 5G system as an example, but embodiments of the present disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, this may include LTE or LTE-A mobile communication and mobile communication technologies developed after 5G. Accordingly, embodiments of the present disclosure may be applied to other communication systems with some modifications within a range that does not significantly deviate from the scope of the present disclosure as judged by a person skilled in the art. The contents of the present disclosure can be applied to FDD, TDD, and / or XDD (or SBFD, full duplex) systems.

[0422] In the following description of the present disclosure, upper layer signaling may be signaling corresponding to at least one or a combination of one or more of the following signaling.

[0423] - MIB (Master Information Block)

[0424] - SIB (System Information Block) or SIB

[0425] - RRC (Radio Resource Control)

[0426] - MAC (Medium Access Control) CE (Control Element)

[0427] In addition, L1 signaling may be signaling corresponding to at least one or a combination of one or more signaling methods using the physical layer channel or signaling below.

[0428] - PDCCH (Physical Downlink Control Channel)

[0429] - DCI (Downlink Control Information)

[0430] - UE-specific DCI

[0431] - Group common DCI

[0432] - Common DCI

[0433] - Scheduling DCI (e.g. DCI used for scheduling downlink or uplink data)

[0434] - Non-scheduled DCI (e.g. DCI not intended for scheduling downlink or uplink data)

[0435] - PUCCH (Physical Uplink Control Channel)

[0436] - UCI (Uplink Control Information)

[0437] The term slot used in the present disclosure below is a general term that may refer to a specific time unit corresponding to a TTI (Transmit Time Interval), and may specifically mean a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system.

[0438] In the present disclosure, deep sleep and ultra deep sleep can be distinguished based on which components within a cell / base station can be turned off. For example, if the main radio (MR) is completely OFF, all components within the main radio can be OFF. When the main radio is in deep sleep, the oscillator, radio frequency-front end (RF-FE), and baseband modem can be OFF, while the control processor and double data rate (DDR) memory can still be ON. When the main radio is in ultra deep sleep, the oscillator, radio frequency-front end (RF-FE), and baseband modem can be OFF, and the control processor and DDR memory can also operate at very low power or be completely OFF.

[0439] The present disclosure can be applied to RRC idle, RRC inactive, and RRC connected terminals.

[0440] In the present disclosure, the statement that a particular cell is for data communication and / or only for data communication may include that the particular cell performs not only data communication but also other signal transmission and reception. For example, signal transmission and reception other than sync and / or connection may be included in data communication.

[0441] In the present disclosure, transitioning a cell to a specific state may include maintaining the specific state without changing the state. For example, transitioning a cell to a deep sleep state or an ultra-deep sleep state may include maintaining the deep sleep state or an ultra-deep sleep state.

[0442] In the present disclosure below, the above examples are described through a number of embodiments, but they are not independent and one or more embodiments may be applied simultaneously or in combination.

[0443] As mentioned above, 5G systems support ultra-wide bandwidth signal transmission and reception or utilize spatial multiplexing using multiple transmit / receive antennas to achieve ultra-high-speed data services reaching several Gbps. Furthermore, they support various power-saving modes to reduce terminal power consumption. However, excessive power consumption can also occur at base stations.

[0444] For example, the number of power amplifiers (PAs) required increases proportionally to the number of transmitting antennas installed at a base station or terminal. The maximum output of the base station and terminal depends on the characteristics of the PA, and the maximum output of the base station generally varies depending on the size of the cell covered by the base station. The maximum output is usually expressed in dBm. The maximum output of the terminal is usually 23 dBm or 26 dBm.

[0445] An example of a commercial 5G base station might feature 64 transmit antennas and corresponding 64 power amplifiers operating in the 3.5 GHz frequency band, operating at a bandwidth of 100 MHz. Ultimately, the base station's energy consumption increases in proportion to the power amplifier output and operating time.

[0446] Compared to LTE base stations, 5G base stations feature relatively high operating frequency bands, resulting in wider bandwidth and numerous transmitting antennas. While these features have the effect of increasing data rates, they also come at the cost of increased base station energy consumption. Therefore, the more base stations that comprise a mobile communications network, the greater the energy consumption of the entire mobile communications network.

[0447] As mentioned above, the energy consumption of a base station is largely dependent on the operation of the power amplifier. Since the power amplifier is involved in the base station's transmission operations, the downlink (DL) transmission operation of the base station is closely related to its energy consumption. The uplink (UL) reception operation of the base station accounts for a relatively small portion of its energy consumption.

[0448] The physical channels and physical signals transmitted by the base station in the downlink are as follows.

[0449] - PDSCH (Physical Downlink Shared Channel): A downlink data channel containing data to be transmitted to one or more terminals.

[0450] - PDCCH (Physical Downlink Control Channel): A downlink control channel that includes scheduling information for PDSCH and PUSCH (Physical Uplink Control Channel). Alternatively, the PDCCH may be transmitted alone without the PDSCH or PUSCH to be scheduled, and control information such as slot format and power control commands may be transmitted on 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.

[0451] - PBCH (Physical Broadcast Channel): A downlink broadcast channel that provides MIB (Master Information Block), which is essential system information required for transmission and reception of data channels and control channels of the terminal.

[0452] - PSS (Primary Synchronization Signal): A signal that serves as the basis for DL ​​time and / or frequency (hereinafter time / frequency) synchronization and provides some cell ID information.

[0453] - SSS (Secondary Synchronization Signal): A signal that serves as the basis for DL ​​time / frequency synchronization and provides some of the remaining information including the cell ID.

[0454] - DM-RS (Demodulation Reference Signal): Reference signal for channel estimation of terminals for each of PDSCH, PDCCH, and PBCH.

[0455] - CSI-RS (Channel-state Information Reference Signal): A downlink signal that serves as a basis for measuring the terminal's downlink channel status.

[0456] - PT-RS (Phase-tracking Reference Signal): Downlink signal for phase tracking

[0457] From the perspective of base station energy saving, when the base station stops downlink transmission operation, the power amplifier operation is stopped accordingly, which increases the base station energy saving effect, and the operation of the remaining base station devices, such as the baseband device as well as the power amplifier, is also reduced, enabling additional energy saving.

[0458] Similarly, even if uplink reception operations account for a relatively small portion of the base station's total energy consumption, additional energy savings can be achieved if uplink reception operations can be stopped.

[0459] The downlink transmission behavior of a base station fundamentally depends on the amount of downlink traffic. For example, if there is no data to transmit to the terminal via the downlink, the base station does not need to transmit the PDSCH or the PDCCH to schedule the PDSCH. Alternatively, if the data can be temporarily delayed for reasons such as insensitivity to transmission delay, the base station may refrain from transmitting the PDSCH and / or PDCCH.

[0460] In contrast, physical channels and physical signals such as PSS, SSS, PBCH, and CSI-RS have the characteristic of being repeatedly transmitted at a predetermined, promised cycle, 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, radio link quality, etc. In other words, the PSS, SSS, PBCH, and CSI-RS must be transmitted on the downlink regardless of downlink data traffic, and this causes base station energy consumption. Therefore, base station energy savings can be achieved by controlling the transmission of the signals unrelated to (or with low relevance to) data traffic to occur less frequently.

[0461] Through the above two base station energy saving methods, 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 period when the base station does not perform downlink transmission.

[0462] Alternatively, energy consumption at a base station can be reduced by switching off some of its antennas or power amplifiers. However, this energy-saving effect may be counterproductive, such as reduced cell coverage or throughput.

[0463] For example, if a base station equipped with 64 transmit antennas and corresponding 64 power amplifiers in the 3.5 GHz frequency band as described above and operating with a bandwidth of 100 MHz activates only 4 transmit antennas and 4 power amplifiers for a certain period of time and switches off the rest in order to save base station energy, the base station energy consumption during that period will be reduced to approximately 1 / 16 (=4 / 64), but it will be difficult to achieve cell coverage and throughput assuming the existing 64 antennas and power amplifiers due to the decrease in maximum transmission power and decrease in beamforming gain.

[0464] The above base station energy saving methods can be further categorized into three types. There is a base station energy saving method in the frequency domain that adjusts the size of the BWP according to the base station traffic, a base station energy saving method in the space 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 base station energy saving methods are used alone or in combination according to the characteristics of the base station, such as base station traffic or coverage, and the corresponding change information must be shared / transmitted to the terminal.

[0465]

[0466] Consequently, in a situation where the information changed above or the energy saving mode is shared with the terminal, the impact of the energy saving mode on energy-consuming technologies such as CA / DC (carrier aggregation / dual connectivity), PDSCH / PUSCH / PUCCH repetition, and mTRP (multi-TRP) should be examined.

[0467] The following describes the base station energy-saving method proposed in this disclosure through specific examples. The following examples may be implemented separately and / or at least in combination.

[0468] First, we can consider the structure of a network communication system to achieve energy saving.

[0469] FIG. 15 is a diagram for explaining an existing network communication system according to one embodiment of the present disclosure.

[0470] Referring to Fig. 15, multiple cells, Cell 1, Cell 2, 3, and 4, are illustrated. Since all cells must support not only connected terminals (or connected terminals, terminals in RRC connected state) but also idle terminals (or idle terminals, terminals in RRC idle state) (and / or terminals in RRC inactive state), even when there is no traffic, the base station has no choice but to save energy in short periods, such as light sleep or micro sleep, for periodic reference signal (e.g., SSB) transmission.

[0471] Although multiple cells are illustrated in FIG. 15, it is noted that a cell may correspond to at least one of a Distributed Unit (DU), a Radio Unit (RU), a Transmission and Reception Point (TRP), or a carrier, but is not limited thereto.

[0472] Referring to Fig. 15, an idle terminal synchronizes with a cell transmitting a sync signal (e.g., Cell 1), selects a cell for initial access, and performs a RACH (Random Access Channel) procedure to finally access the cell. Fig. 15 illustrates a case where a terminal accesses Cell 1 and performs communication. In the existing communication system of Fig. 15, it may be difficult to save network power because all cells are powered on for synchronization / access with the terminal in consideration of the mobility of the idle terminal.

[0473] FIG. 16a and FIG. 16b are diagrams for explaining a network communication system for realizing energy saving according to one embodiment of the present disclosure.

[0474] 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 may be a sync / access cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be cells (data cells) that do not perform the sync / access function but only perform data communication with a terminal. For example, a cell that performs only data communication to a terminal may include not only a cell that is only for / performs data communication, but also a cell that performs a function other than the sync / access function. For example, the data communication may include transmitting and receiving a reference signal and / or other signals. 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, in the present disclosure, Cell 2 can be understood as one or more cells in contrast to Cell 1.

[0475] Although multiple cells are illustrated in FIG. 16a, it is noted that a cell may correspond to at least one of a Distributed Unit (DU), a Radio Unit (RU), a Transmission and Reception Point (TRP), or a carrier, but is not limited thereto.

[0476] Referring to Fig. 16a, an idle terminal synchronizes with Cell 1 transmitting a sync signal and performs a RACH (Random Access Channel) procedure for Cell 1 to perform initial access, thereby finally accessing Cell 1. After initial access to Cell 1, the terminal attempts to access a cell (e.g., Cell 2A, Cell 2B, or Cell 2C) to actually transmit and receive data. In Fig. 16a, it is assumed that Cell 1 can control Cell 2A, Cell 2B, and Cell 2C to save network power. Therefore, Cell 1 can provide the terminal with settings for the cells controlled by Cell 1 (1601). In addition, Cell 1 can determine the cells to be controlled through an inter-cell interface (1602).

[0477] Specifically, Cell 1 can control the Tx / Rx power on / off of the controlled cell(s), for example, Cell 2A, Cell 2B, and / or Cell 2C. Accordingly, when Cell 1 requests Tx / Rx power on to the cell(s) it controls (1603), the cell(s) can transmit and receive signals with the terminal. Cell 1 can transmit the Tx / Rx power on request to one or more of the cells it controls, and the cell that receives the request can perform an operation accordingly. For example, when Cell 1 requests Tx / Rx power on to Cell 2A, Cell 2A can perform data communication with the terminal.

[0478] There may be various methods for turning on / off the Tx / Rx power of the cell(s) controlled by Cell 1. For example, the location information of the terminal may be utilized. For example, based on the location information of the terminal, Cell 2A may be determined as the cell for data communication with the terminal among Cells 2A to 2C, and Cell 1 may 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 the method to a specific method.

[0479] Through a method according to an embodiment of the present disclosure illustrated in FIG. 16A, Cell 2A, Cell 2B, and Cell 2C can be in a deep sleep state, and only the cell(s) with Tx / Rx on at the request of Cell 1 can be powered on (On state) and transmit signals to and / or receive signals from the terminal.

[0480] In Fig. 16a, a reference signal is illustrated as a signal transmitted by a cell(s) with Tx / Rx turned on. However, it should be noted that the present disclosure does not limit the signal transmitted by the cell(s) with Tx / Rx turned on to a specific signal. Accordingly, the terminal will be able to receive the reference signal from the cell(s) with Tx / Rx turned on and perform data communication. In Fig. 16a, a case in which the terminal performs data communication with Cell 2A is illustrated.

[0481] 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 may be a cell for sync (synchronization cell) and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be cells that perform initial connection and data communication with a terminal (connection / data cells) without performing the function of sync. It should be noted that although a plurality of cells are illustrated in FIG. 16b, a cell may correspond to at least one of a DU (Distributed Unit), a RU (Radio Unit), a TRP (Transmission and Reception Point), or a carrier, but is not limited thereto.

[0482] Referring to Fig. 16b, an idle terminal can synchronize with a cell transmitting a sync signal and select the corresponding cell. Fig. 16b illustrates a case where Cell 1 is selected.

[0483] In Fig. 16b, it is assumed that Cell 1 can control Cell 2 (Cell 2A, Cell 2B, Cell 2C) to save network power. Therefore, Cell 1 can provide the terminal with settings for the cells controlled by Cell 1 (1604). And / or Cell 1 can determine the cells to be controlled (1605) through the inter-cell interface.

[0484] Specifically, Cell 1 can control the Tx / Rx power on / off of the controlled cell(s), for example, Cell 2A, Cell 2B, and / or Cell 2C. Accordingly, when Cell 1 requests Tx / Rx power on to the cell(s) it controls (1606), the cell(s) can transmit and receive signals with the terminal. Cell 1 can transmit the Tx / Rx power on request to one or more of the cells it controls, and the cell that receives the request can perform an operation accordingly. For example, when Cell 1 requests Tx / Rx power on to Cell 2A, Cell 2A can perform data communication with the terminal.

[0485] There may be various methods for turning on / off the Tx / Rx power of the cell(s) controlled by Cell 1. For example, the location information of the terminal may be utilized. For example, based on the location information of the terminal, Cell 2A may be determined as the cell for data communication with the terminal among Cells 2A to 2C, and Cell 1 may 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 the method to a specific method.

[0486] According to a method according to an embodiment of the present disclosure illustrated in FIG. 16b, Cell 2 (Cell 2A, Cell 2B, Cell 2C) can be in a deep sleep state, and only the cell(s) that have Tx / Rx turned on at the request of Cell 1 can be powered on (On state) to transmit signals to and / or receive signals from the terminal. Although a reference signal is illustrated as a signal transmitted by the cell(s) that have Tx / Rx turned on in FIG. 16b, it should be noted that the present disclosure does not limit the signals transmitted by the cell(s) that have Tx / Rx turned on to a specific signal. Unlike FIG. 16a, FIG. 16b illustrates a case where a RACH (Random Access Channel) procedure is performed with the cell(s) that have Tx / Rx turned on by Cell 1. For example, the reference signal may include a signal for sync, and the terminal may have acquired at least DL sync, and / or the terminal may have at least DL sync with Cell 2 (at least one of Cell 2A, 2B, and 2C). Accordingly, the terminal may perform a RACH procedure. In FIG. 16b, a case is illustrated where the terminal performs data communication by connecting after performing the RACH procedure with Cell 2A.

[0487] FIG. 17a and FIG. 17b are diagrams 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 may be a sync / access cell, and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be cells (data cells) that do not perform the sync / access function and only perform data communication to a terminal. For example, a cell that performs only data communication to a terminal may include not only cells that are for / perform only data communication, but also cells that perform functions other than the sync / access function. For example, data communication may include transmitting and receiving a reference signal and / or other signals.

[0489] Unlike FIGS. 16A and 16B, in the system of FIGS. 17A and 17B, Cells 2A, 2B, and 2C may include a WUR (Wake-up receiver). When the cells include a WUR, Cell 2 (Cell 2A, Cell 2B, and Cell 2C) may turn off the MR (Main Radio) and go into an ultra deep sleep state, which may be more advantageous for energy saving. It should be noted that although multiple cells are illustrated in FIG. 17A, a cell may correspond to at least one of a DU (Distributed Unit), a RU (Radio Unit), a TRP (Transmission and Reception Point), or a carrier, but is not limited thereto.

[0490] Referring to Fig. 17a, an idle terminal synchronizes with Cell 1 transmitting a sync signal, selects a cell among Cell 1, Cell 2A, Cell 2B, or Cell 2C to perform initial access, and performs a RACH (Random Access Channel) procedure to finally access 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 can provide the terminal with settings for other cells (Cell 2A, Cell 2B, Cell 2C) (1701). The terminal that receives the information can transmit a WUS (Wake-up signal) to other cells (Cell 2A, Cell 2B, Cell 2C) (1702). And the cells (Cell 2A, Cell 2B, Cell 2C) that were in the ultra deep sleep state can receive the WUS signal and turn on the MR (On state) to transmit a signal to the terminal and / or receive a signal from the terminal.

[0491] If the MR of all cells (Cell 2A, Cell 2B, Cell 2C) are turned on, the network power saving effect may be reduced. Therefore, it is necessary to use various methods to wake up only the necessary cells. 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 equal to or exceeds a predetermined threshold. Here, the strength of the WUS signal may be named WUSRP (Wake-up signal received power). Various methods may be considered for setting the threshold. For example, settings through RRC, MAC-CE, DCI, or a combination thereof may be considered. And / or settings based on the cell-to-cell interface (and / or the base station-to-base station interface) may be considered. And / or the threshold may be set from the core network. And / or the threshold may be predefined. And / or a combination of at least some of the above-described threshold setting methods may be considered. It should also be noted that the present disclosure is not limited to the above-described method for enhancing the effectiveness of network power savings. In other words, the above-described method is merely one embodiment of the present disclosure, and the present disclosure is not limited to the above-described embodiment of the present disclosure.

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

[0493] In Fig. 17a, it is illustrated that the MR of Cell 2A, which has received a WUS, is turned on to transmit a reference signal to the terminal and perform data communication. For example, the terminal can transmit a WUS to Cell 2A, Cell 2B, and Cell 2C. Among these, the MR of Cell 2A, which has received a WUS signal having an intensity equal to or exceeding a threshold, is turned on to transmit a reference signal to the terminal and perform data communication.

[0494] Next, referring to FIG. 17b, multiple cells, for example, Cell 1 and Cell 2 (Cell 2A, Cell 2B, Cell 2C), are illustrated. Unlike FIG. 17a, Cell 1 may be a sync cell (synchronization cell) and Cell 2 (Cell 2A, Cell 2B, Cell 2C) may be cells that perform initial connection and data communication with a terminal without performing the sync function (access / data cells). In the system of FIG. 17a and FIG. 17b, Cell 2 (Cell 2A, Cell 2B, Cell 2C) may include a WUR (Wake-up receiver). When cells include a WUR, Cell 2 (Cell 2A, Cell 2B, Cell 2C) may turn off the MR (Main Radio) and go into an ultra deep sleep state, which may be more advantageous for energy saving. Although multiple cells are illustrated in FIG. 17b, it is noted that a cell may correspond to at least one of a Distributed Unit (DU), a Radio Unit (RU), a Transmission and Reception Point (TRP), or a carrier, but is not limited thereto.

[0495] Referring to Figure 17b, an idle terminal can synchronize with a cell transmitting a sync signal and select the corresponding cell. Figure 17b illustrates a case where Cell 1 is selected.

[0496] In Fig. 17b, it is assumed that Cell 1 can provide information about Cell 2 (Cell 2A, Cell 2B, Cell 2C). Therefore, Cell 1 can provide settings for other cells (Cell 2A, Cell 2B, Cell 2C) to the terminal (1703). The terminal that receives the information can transmit a WUS (Wake-up signal) to other cells (Cell 2A, Cell 2B, Cell 2C) (1704). In addition, the cells that were in the ultra deep sleep state (Cell 2A, Cell 2B, Cell 2C) can receive the WUS signal and turn on the MR (On state) to transmit and / or receive signals to the terminal.

[0497] If the MR of all cells (Cell 2A, Cell 2B, Cell 2C) are turned on, the network power saving effect may be reduced. Therefore, it is necessary to wake up only the necessary cells through various methods. For example, a method may be considered in which the MR is turned on 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 higher than a predetermined threshold. Here, the strength of the WUS signal may be named WUSRP (Wake-up signal received power). The method for setting the threshold may refer to the description of FIG. 17a described above. In addition, it is noted that the method for increasing the network power saving effect in the present disclosure is not limited to the above method.

[0498] In Fig. 17b, a reference signal is illustrated as a signal transmitted by the cell(s) with MR turned on, but it is noted that the present disclosure does not limit the signal to a specific signal.

[0499] Unlike FIG. 17a, FIG. 17b illustrates a case where a terminal performs a RACH (Random Access Channel) procedure with access / data cells (Cell 2A, Cell 2B, Cell 2C). For example, the reference signal may include a signal for synchronization, so that the terminal has acquired at least DL synchronization, and / or the terminal may have at least DL synchronization with Cell 2 (at least one of Cell 2A, 2B, and 2C). Accordingly, the terminal may perform the RACH procedure.

[0500] In Fig. 17b, a case is illustrated where a terminal performs data communication by connecting to Cell 2A after performing a RACH procedure. For example, the terminal can transmit WUS to Cell 2A, Cell 2B, and Cell 2C. Among these, the MR of Cell 2A, which receives a WUS signal having an intensity equal to or exceeding a threshold, turns on and transmits a reference signal to the terminal, and the terminal can perform a RACH procedure for Cell 2A to connect to Cell 2A. Thereafter, data communication can be performed between the terminal and Cell 2A.

[0501] For RRC_IDLE terminals, the synchronization cell becomes the PCell (primary cell), and for RRC_CONNECTED terminals, the data cell becomes the PCell. RRC_CONNECTED terminals can configure another data cell as an SCell (secondary cell) if necessary depending on the situation. Also, if dual connectivity is supported, another data cell or synchronization cell can be configured as an SCG (secondary cell group). Alternatively, the synchronization cell and the data cells below it can become an MCG (master cell group). In this case, the PCell becomes the synchronization cell, and the data cells below it can become the SCell. In the case of an SCG, it can be composed of another synchronization cell and the data cells below it, and the synchronization cell can become the PSCell (primary SCG cell). Alternatively, all base stations belonging to the MCG and SCG can be data cells. The PCell can be changed depending on the entity that confirms the paging, and the PCell can be configured regardless of this entity.

[0502] Next, a method for reducing latency in which a terminal accesses a data cell from a synchronous cell in a cell structure according to one embodiment of the present disclosure is described.

[0503] FIG. 18 is a diagram illustrating a classification of latency from when a terminal camped on a synchronous cell in the cell structure of FIGS. 15 to 17b according to an embodiment of the present disclosure to when data traffic occurs and the terminal accesses the data cell and receives all packets.

[0504] Referring to Figure 18, T is the time from the time when data traffic occurs (1801) at a terminal camped on a synchronous cell to the time when data starts to be transmitted from the data cell (1802). Access(access latency, 1804), the time from when data starts to be transmitted in the data cell (1802) until all generated traffic is exhausted (1803) is T Packet (packet latency, 1805), then the total latency is T Access + T Packet This latency increases the waiting time of the base station and terminal, which not only increases the overall energy consumption but also reduces the throughput, so reducing the latency is essential for efficiently operating the cell structure of FIGS. 16a to 17b.

[0505] To reduce latency, first T Packet (1805) is difficult to reduce because the time consumed for packet transmission is determined by the channel status between the data cell and the terminal, and the cell structure of Fig. 15 also has the same latency.

[0506] The latency generated by the cell structure of Figs. 16a to 17b is T Access (1804) can be said to be T CellSearch (Data cell search latency, 1806) and T Sync+RA (Data cell synchronization and random access latency, 1807) can be subdivided into T first. CellSearchIn the case of (1806), it is the latency required to select one of the data cells within or near the synchronous cell where the terminal is camping on. If all candidates for the data cells are activated, as in the cell structure of Fig. 15, the terminal will measure the RS (reference signal) from the activated data cells and connect to the data cell with the best signal strength, so the time required to select the data cell will be very short. However, in the cell structure of Figs. 16a and 17b, since the data cells may be inactive, it may take a very long time to receive the RS from the data cell and measure the signal strength. For example, if the data cell with the highest signal strength in a certain terminal is in a deep sleep state, the time required to wake up this data cell will be long, so T CellSearch (1806) increases. There are many ways to reduce this, but the most reliable way is to select the best data cell among the activated data cells instead of always connecting to the best data cell. At this time, T CellSearch can be greatly reduced, but if the channel condition between the selected data cell and the terminal is not good, T Packet It is important to carefully consider these trade-offs and choose the optimal data cell, as this can take a long time.

[0507] Next is T Sync+RAThis represents the time it takes for a terminal to receive a downlink RS from a data cell, synchronize, and access the selected data cell, when the terminal has already selected the best or second-best data cell and the data cell is active. When a terminal camps on a synchronization cell, it is synchronized in time and frequency with the synchronization cell, but not with the data cell. If the data cell uses the same frequency band as the synchronization cell, the terminal can synchronize with the data cell immediately through the synchronization process. However, if the data cell and the synchronization cell use different frequency bands, the terminal must receive several downlink RSs from the data cell to synchronize. If three downlink RSs are received at 20ms intervals to synchronize the terminal and the data cell, the synchronization process alone will take about 60ms, so reducing this time is very important. To reduce this time, a shorter downlink RS burst can be transmitted, allowing the terminal to receive several RSs in a short period of time, thus performing the synchronization process much faster than 60ms.

[0508] CA also has a similar feature called fast SCell activation, which allows rapid synchronization between the SCell and the UE on the PCell. Fast SCell activation occurs when an RRC_CONNECTED UE receives a SCell allocated for CA. This allows the UE to quickly synchronize with the previously deactivated SCell by receiving a TRS (tracking reference signal) burst from the SCell. To achieve this, the PCell notifies the UE of which SCell and which TRS burst will be emitted, triggering the UE. The UE then receives a TRS burst from the SCell a specific time after the trigger.

[0509] To facilitate rapid SCell activation during CA configuration, a dormant BWP can be configured for an SCell. If the Active BWP of an activated SCell is a dormant BWP, the UE stops monitoring PDCCHs and transmitting SRS / PUSCH / PUCCH on the SCell. However, if a dormant BWP is configured, CSI measurements, AGC (auto gain control), and beam management can continue. DCI is used to control the activation / deactivation of dormant BWPs for one or more SCell(s) or one or more SCell groups(s).

[0510] To enable fast SCell activation during CA configuration, aperiodic CSI-RS can be configured to track fast SCell activation, allowing SCells to assist AGC and time / frequency synchronization. MAC CE is used to trigger the activation of one or more SCell(s) and trigger aperiodic CSI-RS to track fast SCell activation on deactivated SCell(s).

[0511] FIG. 19 is a diagram illustrating a two-octet structure of a trigger for MAC CE-based fast SCell activation according to an embodiment of the present disclosure.

[0512] Figure 19 (a) is one octet C i The structure of an Enhanced SCell Activation / Deactivation MAC CE having a field is illustrated. Referring to Fig. 19 (a), the Enhanced SCell Activation / Deactivation MAC CE having a single octet Ci field is identified by a MAC subheader with an eLCID. The size is variable and the number of C to be activatedi 7 C-fields, 1 R-field, TRS ID based on ScellIndex for SCell indicated by field(s) j It consists of 0 or more fields in ascending order.

[0513] Figure 19 (b) shows four octet C i The Enhanced SCell Activation / Deactivation MAC CE structure with a field is illustrated. Referring to (b) of Fig. 19, four octet C i Enhanced SCell Activation / Deactivation MAC CE with field is identified by MAC subheader with specified eLCID. Size is variable and can be used to determine the number of C to be activated. i 31 C-fields, 1 R-field, and 0 or more TRS IDs based on the ScellIndex for the SCell indicated by field(s). j It is organized in ascending order by field.

[0514] The definitions for each field in the Enhanced SCell Activation / Deactivation MAC CE of Fig. 19 are specifically as follows.

[0515] - C i : If the MAC entity has an SCell configured, this field indicates the activation / deactivation status of the SCell with SCellIndex i, otherwise the MAC entity is C i Ignore field C i The field must be activated for the SCell with SCellIndex i, and the TRS ID for the SCell j Set to 1 to indicate that the field is included. C i The field is set to 0 to indicate that the SCell with SCellIndex i is disabled and does not contain a TRS ID field for this SCell.

[0516] - TRS ID j : TRS ID j If scellActivationRSId is set to a non-zero value, it indicates that the corresponding TRS is activated. TRS ID j If set to 0, it indicates that TRS is not used for that SCell.

[0517] - R: Reserved bit, set to 0.

[0518] FIG. 20 is a diagram showing a timeline for fast SCell activation according to one embodiment of the present disclosure.

[0519] The UE configures aperiodic CSI-RS resources for tracking SCells for fast SCell activation using NZP-CSI-RS-ResourceSet(s) with higher layer parameter scellActivationRS-ConfigToAddModList, and the QCL relationship can be provided with higher layer parameter qcl-Info.

[0520] Referring to FIG. 20, the PCell may transmit an Enhanced Scell ​​Activation / Deactivation MAC-CE in the n-th slot (2001) that triggers one or two CSI-RS bursts for fast SCell activation for deactivated SCell(s).

[0521] When the terminal receives this,

[0522] - If MAC-CE indicates that the first CSI-RS burst for SCell activation exists on the SCell, the UE can assume that the first CSI-RS burst for SCell activation exists on the SCell. The first slot of the first CSI-RS burst starts from the m1SCell slot (2011) after the last SCell slot that matches the reference slot n+k.

[0523] - If the MAC-CE indicates that a second CSI-RS burst for SCell activation exists on the SCell, the UE can assume that a second CSI-RS burst for SCell activation exists on the SCell. The first slot of the second CSI-RS burst starts from the m2SCell slot (2021) after the end of the first CSI-RS burst. The CSI-RS of the second burst must have the same antenna port index, OFDM symbol allocation within the slot, and same PRB allocation position as the CSI-RS of the first burst.

[0524] - A CSI-RS burst is defined as 4 CSI-RS resources in 2 consecutive slots, and m1 and m2 are provided by gapBetweenBursts associated with CSI-RS burst(s) triggered by aperiodicTriggeringOffsetL2 and MAC-CE of NZP-CSI-RS-ResourceSet, respectively.

[0525] Unlike the fast SCell activation described above, many things need to change to quickly activate data cells in cell structures such as those in FIGS. 16a to 17b.

[0526] First, since the target is a terminal in RRC_IDLE or INACTIVE state rather than an RRC_CONNECTED terminal, the terminal may not have RRC configuration, so information about TRS and SCell can be provided to the terminal through SIB. RRC_IDLE / INACTIVE terminals can also receive TRS, and the terminal can receive the TRS configuration through SIB17 of Table 37-1.

[0527] [Table 37-1]

[0528]

[0529] Table 37-2 describes the parameters in SIB17 of Table 37-1.

[0530] [Table 37-2]

[0531]

[0532] As above, after SIB17 is configured in the terminal, the base station can indicate to the terminal which TRS resource set is configured through the TRS availability indication of DCI format 1_0 and DCI format 2_7 CRC-scrambled with P-RNTI. There is no new TRS pattern or type for RRC_IDLE / INACTIVE terminals, and when TRS is configured for a terminal that is currently in RRC_CONNECTED state in the network, the corresponding TRS resource set can be configured identically for RRC_IDLE / INACTIVE terminals. Therefore, if TRS is not configured for an RRC_CONNECTED terminal, TRS availability indication cannot be configured for RRC_IDLE / INACTIVE terminals. Similarly, the TRS configuration for RRC_IDLE / INACTIVE terminals can reuse the structure of SIB17. However, since information about data cells is also needed, additional candidate data cell(s) IDs may be included within SIB17-IEs, or the candidate data cell(s) IDs may be transmitted to SIB1, and for each data cell, all TRS configurations specified in SIB17-IEs may be considered valid. The actual terminology used, such as SIB17, may vary.

[0533] Next, we will discuss the channel used for actual rapid activation among the TRS configurations set in the synchronization cell. Since the data cell is in a sleep state, it must be triggered by the synchronization cell. As mentioned above, SIB is responsible for setting the configuration to the terminal, making dynamic indication difficult. Furthermore, since MAC CE or RRC is difficult because the terminal is not assigned an RRC configuration, this can be indicated based on DCI. For example, the synchronization cell can trigger rapid activation of the data cell in the terminal through DCI format 1_0 scrambled with P-RNTI. Table 38 shows the structure of DCI format 1_0 scrambled with P-RNTI, and Table 39 shows the short message indicator, one of the fields in Table 38.

[0534]

[0535] The description of 'note' in Table 38 is as follows.

[0536] * (If only the short message is carried, this bit field is reserved)

[0537] ** M = 1 ~ 6 bits (if TRS-ResourceSetConfig is configured), 0 (otherwise)

[0538] *** with spectrum sharing or without spectrum sharing

[0539] In Table 38 is the size of CORESET 0. The Short Messages Indicator in the first row of Table 38 is 2 bits of information that indicates whether it is short message information, paging information, or both, as shown in Table 40.

[0540] Bit fieldShort Message indicator00Reserved01Only scheduling information for Paging is present in the DCI10Only short message is present in the DCI11Both scheduling information for Paging and short message are present in the DCI

[0541] Here, a short message includes information related to changes in system information or disasters, as shown in Table 40.

[0542] BitShort Message1systemInfoModification2etwsAndCmasIndication3stopPagingMonitoring4systemInfoModification-eDRX5 - 8Not used in this release of the specification, and shall be ignored by UE if received.

[0543] To ensure fast activation of data cells, a TRS burst can be allocated when traffic is present at the terminal. In this case, if the terminal confirms that it has received a paging signal through the DCI format 1_0 CRC-scrambled with the P-RNTI, and the short message indicator in Table 39 indicates 01 or 11, it recognizes that the paging signal is downlink traffic and requires random access to the data cell to receive it. The terminal expects that a TRS is present in the data cell it is attempting to access, and synchronizes and accesses it by receiving the TRS indicated by the TRS availability indication. However, if the data cell is in a sleep state, it is difficult to dynamically indicate the ramp-up time, so the terminal may need to continuously monitor the TRS.

[0544] Another method is to explicitly set additional fields in the DCI. As shown in Tables 38-40, there are a large number of reserved bits, which can be used to indicate which data cells are candidates for activation using bits or bitmaps. For example, if the synchronization cell is 1100010, there are seven data cells that can be indicated, and the terminal can consider the first, second, and sixth data cells as candidates for activation. Additionally, the synchronization cell can directly indicate the ramp-up time depending on the sleep state of the data cell.

[0545] Alternatively, a combination of the implicit and explicit methods described above could be considered. For example, if the short message indicator is set to 01 or 11, the data cell candidates are explicitly indicated as bits or bitmaps, and both the ramp-up transition time and the TRS availability indication are indicated, so that the terminal can know which TRS is transmitted in which data cell(s). Of course, similar functions can be indicated in CRC-srambled DCI format 1_0 or DCI format 2_7 or newly defined DCI, such as C-RNTI, SI-RNTI, RA-RNTI, MsgB-RNTI, etc.

[0546] Finally, there may be a change in timing, that is, when the terminal receives the trigger and receives the TRS from the actual data cell. After receiving the trigger for fast data cell activation through DCI in the nth slot, T CellSearchIf the following is called n+k slot, the terminal may output the first TRS burst after m1slot based on n+k slots, similar to Fast SCell activation, and the second TRS burst may output after m2slot based on m1slot. Information about m1 and m2 can be provided in the same way in aperiodicTriggeringOffsetL2 and gapBetweenBursts, respectively. However, since the above information is provided through RRC of NZP-CSI-RS-ResourceSet and SCellActivationRS-Config, respectively, a context with a similar function as above can be included in TRS-ResourceSet of Table 37, as shown in Table 41. In addition, since the second TRS burst must have a QCL relationship with the first TRS burst, the corresponding qcl-Info can also be provided in TRS-ResourceSet.

[0547]

[0548] Ultimately, if information about m1 and m2 is transmitted similarly through SIB17, the terminal can determine the timing of the TRS burst transmission in the data cell based on how slot k is configured from slot n to slot n+k. This timing can vary significantly depending on the state of the data cell. For example, suppose data cell 1 is in light sleep and data cell 2 is in deep sleep, a deeper sleep state than light sleep. Therefore, the transition time to become active will be longer for data cell 2, which requires more components to be turned on than for data cell 1. Unless the synchronization cell provides this information for each data cell, the terminal will have difficulty detecting this. Without this information, the terminal must continuously search for TRS, which increases terminal power consumption. On the other hand, if the synchronization cell provides this information, the terminal can determine the exact timing of the TRS transmission. However, as the number of data cell candidates increases, reporting the state of each data cell can incur significant overhead. Therefore, the synchronization cell can quantize the transition time and report it to the terminal. For example, it can be expressed as {0, 6, 50, 200ms} with 2 bit information for 00, 01, 10, 11. That is, quatizedTransitionTime can be added to SIB17-IEs as shown in Table 42. Here, the size X for the bitmap means the quantization level.

[0549]

[0550] When quatizedTransitionTime is set, the terminal can accurately determine the location of the TRS through a maximum of 2^X attempts. However, as the size of X increases, the terminal may need to wake up more frequently, so a specific value among the values ​​defined in quatizedTransitionTime can be indicated through DCI. The value can be transmitted together with the PDCCH that dynamically indicates the ID of the data cell or the TRS ID. Since the terminal can know the ID of the data cell to be activated and what transition time it has, the terminal can accurately receive the TRS with only one attempt.

[0551] Meanwhile, in relation to slots for PUCCH transmission in a cell structure such as FIG. 15, if the UE receives an activation command on the PDSCH for SCell to be terminated in slot n, the UE may perform SCell activation after slot n+k, except in the following cases.

[0552] - Tasks related to CSI reporting for serving cells activated in n+k slots

[0553] - Tasks related to sCellDeactivationTimer related to SCell applied by UE in n+k slot

[0554] - Tasks related to CSI reporting for serving cells that are not activated in n+k slots, applied by the UE after the earliest n+k slot.

[0555] Here k is , k1 is the number of slots for PUCCH transmission with HARQ-ACK information for PDSCH reception and is indicated by the PDSCH-to-HARQ feedback timing indicator field in the DCI format, where is the number of slots per subframe, which is the SCS configuration of PUCCH transmission.

[0556] Similarly, in the cell structures of FIGS. 16a to 17b, TRS can also be received from the data cell after n+k slots. However, since it is not in the RRC_CONNECTED state, information about HARQ-ACK feedback is not required, so the definition of k may be different.

[0557] FIG. 21a, FIG. 21b, and FIG. 21c illustrate three timelines from the time traffic is generated for a terminal to the time when a data cell is activated according to one embodiment of the present disclosure.

[0558] Figures 21a and 21b illustrate a scenario in which there is no WUR in the data cell, as in Figures 16a and 16b.

[0559] Referring to Figure 21a, after traffic generation (2101), a synchronous cell can transmit paging to a terminal. Since the location where paging can be received is determined according to the terminal ID, T Paging (2106) can be received by the terminal (2102) with a delay time of β = T. If it is assumed that the terminal receives a trigger for dynamically activating a fast data cell as DCI while receiving paging, the current time can be the nth slot. At the same time, the synchronous cell can activate the data cell(s) appropriate for the terminal. If it is assumed that the synchronous cell and the data cell share a DU and are separated by RU, the synchronous cell can trigger the activation of the data cell (2103) through the fronthaul, middlehaul, or backhaul. The time taken for this is β = T. XH,activation (2107), the current point in time is the n+ β-th slot. The data cell that was in the sleep state is T from the n+ β-th slot. transition(2108) After the state transition, it can be finally activated (2104). The point in time at this time becomes the n+kth slot. The time corresponding to the k slot can be indicated to the terminal as a raw value or a quantization value through DCI as in the above-described embodiment, or the terminal can perform a try and error according to a pre-configured value. If the time corresponding to the β slot is determined, the β information is transmitted through SIB17, and the synchronous cell can notify the terminal of the time of only the k- β slot through DCI.

[0560] Referring to Figure 21b, after a tripeak occurs (2111), the synchronous cell transmits the data cell(s) in advance through the fronthaul, middlehaul, or backhaul to reduce latency. XH,activation (2117) can trigger activation (2112). The synchronization cell can transmit paging according to the location where the terminal can receive paging. For example, the synchronization cell can transmit paging after traffic occurrence (2111) T paging (2116) After the time, the paging can be transmitted. The data cell that was in the sleep state is T transition (2118) After a state transition, the final activation can be achieved (2114). After the terminal receives paging (2113), the data cell can be fully activated (2114) k slots later. The time corresponding to the k slot can be indicated to the terminal as a raw value or quantization value via DCI as in the above-described embodiment, or the terminal can perform try&error based on a pre-configured value.

[0561] Referring to Figure 21c, after traffic occurs (2121), the synchronous cell can transmit paging to the terminal. Since the location where paging can be received is determined according to the terminal ID, T Paging (2129) can be received by the terminal (2122) with a delay time of (2129). If it is assumed that the terminal receives a trigger for dynamic fast data cell activation with DCI while receiving the paging, the current time becomes the nth slot. At the same time, the synchronization cell can trigger the WUS to select the data cell(s) suitable for the terminal (2123). For example, the synchronization cell can be received by the terminal from the paging reception (2122) to T wus,trigger (2130) After WUS can be triggered (2123). When WUS is triggered, the terminal has a T with WUS occasion. WUS, Tx (2131) After transmitting the WUS (2124), the WUS is received in the WUR in the data cell, and if it meets the criteria (e.g., if the RSRP is higher than the configured threshold), the corresponding power level or RSRP can be reported (2125) to the synchronization cell through the fronthaul, middlehaul, or backhaul. If multiple data cells are suitable, the synchronization cell can instruct (2126) the data cell with the strongest reception power to be activated through the fronthaul, middlehaul, or backhaul. For example, the synchronization cell can receive the report (2125) from T XH,activation(2133) After that, a data cell can be activated (2126). In some cases, since reporting and activation instructions through the fronthaul, middlehaul, or backhaul can cause more latency, they can be omitted and activated immediately if the received WUS meets the criteria. At this time, the activation trigger point (2126) is the n+ β-th slot, and can be fully activated (2127) after the transition time (2134). This point in time becomes the n+k-th slot. The time corresponding to the k slot can be indicated to the terminal as a raw value or quantization value through DCI as in the above-described embodiment, or the terminal can perform try&error according to a pre-configured value. If the time corresponding to the β slot is determined, the β information is transmitted through SIB17, and the synchronization cell can only notify the terminal of the time of the k- β slot through DCI.

[0562] In the above defined configuration, even if the terminal receives the configuration for fast data cell activation through SIB, if no dynamic instruction, i.e., trigger, is received through DCI, the terminal can assume that fast data cell activation is disabled.

[0563] FIG. 22 illustrates signaling between a terminal and a base station operating based on fast data cell activation according to one embodiment of the present disclosure.

[0564] The terminal and base station of FIG. 22 can operate based on the above-described embodiment. The signaling order of FIG. 22 can be changed, and two or more operations can be combined and performed as a single step. Furthermore, some operations may be omitted in some cases.

[0565] Referring to FIG. 22, in operation 2210, a terminal may receive a system information block. The terminal may be in an RRC idle state or an RRC inactive state. The system information block may be received from a first cell (or a base station associated with the first cell) on which the terminal is camped. That is, the first cell (or a base station associated with the first cell) on which the terminal is camped may transmit the system information block to the terminal. For example, the system information block may be SIB17 of the embodiment described above. For example, the system information block may include identifiers of candidate cells having data traffic to be transmitted to the terminal.

[0566] In operation 2220, the terminal can receive a PDCCH including a DCI format from a first cell (or a base station associated with the first cell). That is, the first cell (or a base station associated with the first cell) can transmit a PDCCH including a DCI format to the terminal. For example, the DCI format can include information for triggering activation of a second cell. For example, the CRC of the DCI format can be scrambled with a P-RNTI. In this case, the DCI format can include a short message indicator field. The terminal can determine to perform a random access procedure to the second cell based on the short message indicator field.

[0567] At step 2225, the first cell (or a base station associated with the first cell) may transmit information indicating activation to the second cell (or a base station associated with the second cell). The second cell (or a base station associated with the second cell) may be switched from a sleep state to an active state based on the information.

[0568] In operation 2230, the terminal may perform a synchronization procedure with the second cell. For example, the synchronization procedure may be performed a first time after the time at which the terminal receives the PDCCH. For example, the first time may be composed of the sum of (i) a second time at which the first cell triggers the activation of the second cell, and (ii) a third time required for the second cell to transition from a sleep state to an active state. For example, information regarding the second time may be included in the system information block, and information regarding the third time may be included in the DCI format.

[0569] In operation 2240, the terminal can receive data traffic from a second cell (or a base station associated with the second cell). The second cell (or a base station associated with the second cell) can transmit data traffic to the terminal.

[0570] Figure 23 illustrates a terminal transceiver device according to one embodiment of the present disclosure. For convenience of explanation, the illustration and description of devices not directly related to the present disclosure may be omitted.

[0571] Referring to FIG. 23, the terminal may include a transmitter (2304) including an uplink transmission processing block (2301), a multiplexer (2302), and a transmission RF block (2303), a receiver (2308) including a downlink reception processing block (2305), a demultiplexer (2306), and a reception RF block (2307), and a control unit (2309).

[0572] The control unit (2309) can control each of the configuration blocks of the receiving unit (2308) for receiving a data channel or control channel transmitted by the base station as described above and each of the configuration blocks of the transmitting unit (2304) for transmitting an uplink signal.

[0573] In the transmitter (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 in the uplink transmission processing block (2301) can be multiplexed with another uplink signal by a multiplexer (2302), and then transmitted to the base station after signal processing in the transmission RF block (2303).

[0574] The terminal's receiving unit (2308) demultiplexes the signal received from the base station and distributes it to each downlink receiving processing block. The downlink receiving processing block (2305) can perform processes such as demodulation and channel decoding on the downlink signal of the base station to obtain control information or data transmitted by the base station. The terminal receiving unit (2308) can support the operation of the control unit (2309) by applying the output result of the downlink receiving processing block to the control unit (2309).

[0575] FIG. 24 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0576] Referring to FIG. 24, the terminal 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 or fewer components than the components described above. In addition, 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 transmitter (2204) and receiver (2208) of FIG. 22. In addition, the processor (2430) of FIG. 24 may include the control unit (2209) of FIG. 22.

[0577] According to one embodiment, the processor (2430) may control a series of processes by which the terminal may operate according to the above-described embodiment of the present disclosure. For example, according to the embodiment of the present disclosure, the components of the terminal may be controlled to perform a transmission and reception method of the terminal depending on whether the base station mode is the base station energy saving mode or the base station normal mode. For example, the processor (2430) may be configured to receive a system information block from a first cell on which the terminal in an RRC standby or RRC inactive state is camped, receive a PDCCH including a DCI format from the first cell, the DCI format including information for triggering activation of a second cell, perform a synchronization procedure to the second cell after a first time from the time of receiving the PDCCH, and receive data traffic from the second cell. There may be one or more processors (2430), and the processors (2430) may perform transmission and reception operations of a terminal in a wireless communication system applying the carrier bundle of the present disclosure described above by executing a program stored in the memory (2420).

[0578] The transceiver (2410) can transmit and receive signals with a base station. The signals transmitted and received with the base station can include control information and data. The transceiver (2410) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, an RF receiver that low-noise amplifies a received signal and down-converts the frequency, etc. However, the transceiver (2410) is only one embodiment, and the components of the transceiver (2410) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (2410) can receive a signal through a wireless channel and output it to the processor (2430), and transmit a signal output from the processor (2430) through the wireless channel.

[0579] According to one embodiment, the memory (2420) can store programs and data necessary for the operation of the terminal. In addition, the memory (2420) can store control information or data included in signals transmitted and received by the terminal. The memory (2420) can be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, the number of memories (2420) can be plural. According to one embodiment, the memory (2420) can store a program for performing transmission and reception operations of the terminal depending on whether the base station mode of the embodiments of the present disclosure described above is a base station energy saving mode or a base station normal mode.

[0580] FIG. 25 is a block diagram of a base station according to one embodiment of the present disclosure.

[0581] Referring to FIG. 25, the base station 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 or fewer components than the components described above. Furthermore, the processor (2530), the transceiver (2510), and the memory (2520) may be implemented in the form of a single chip.

[0582] The processor (2530) may control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure. For example, the processor may control components of the base station to perform a method of scheduling a terminal depending on whether the base station mode is the base station energy saving mode or the base station normal mode according to the embodiment of the present disclosure. The processor (2530) transmits a system information block to a terminal in an RRC standby or RRC inactive state, and the terminal is camped on the first cell, transmits a PDCCH including a DCI format to the terminal, the DCI format includes information for triggering the activation of a second cell having data traffic to be transmitted to the terminal, and is configured to transmit information instructing the second cell to activate, and a synchronization procedure with the second cell may be performed after a first time from the time at which the PDCCH is transmitted. There may be one or more processors (2530), and the processors (2530) may perform the above-described method of the present disclosure by executing a program stored in the memory (2520).

[0583] The transceiver (2510) can transmit and receive signals with the terminal. The signals transmitted and received with the terminal can include control information and data. The transceiver (2510) can be configured with an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts a received signal. However, the transceiver (2510) is only one embodiment, and the components of the transceiver (2510) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (2510) can receive a signal through a wireless channel and output it to the processor (2530), and transmit a signal output from the processor (2530) through the wireless channel.

[0584] According to one embodiment, the memory (2520) may store programs and data necessary for the operation of the base station. In addition, the memory (2520) may store control information or data included in signals transmitted and received by the base station. The memory (2520) may be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there may be a plurality of 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.

[0585] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0586] Meanwhile, the present specification and drawings disclose preferred embodiments of the present disclosure, and although specific terms are used, they are used in a general sense only to easily explain the technical contents of the present disclosure and to aid in understanding the disclosure, and are not intended to limit the scope of the present disclosure. It will be apparent to those skilled in the art to which the present disclosure pertains that other modified examples based on the technical idea of ​​the present disclosure are possible in addition to the embodiments disclosed herein. Furthermore, each of the above embodiments can be combined and operated as needed.

[0587] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. A method performed by a terminal in a wireless communication system, A step of receiving a system information block from a first cell on which the terminal in an RRC (radio resource control) idle or RRC inactive state is camped on; A step of receiving a physical downlink control channel (PDCCH) including a downlink control information (DCI) format from the first cell, the DCI format including information for triggering activation of a second cell; A step of performing a synchronization procedure to the second cell after a first time from the time of receiving the PDCCH; and A method comprising the step of receiving data traffic from the second cell.

2. In paragraph 1, A method characterized in that the CRC (cyclic redundancy check) of the above DCI format is scrambled with a P-RNTI (paging-radio network temporary identifier).

3. In paragraph 2, A method characterized by further comprising a step of confirming that a random access procedure is to be performed to the second cell based on a short message indicator field included in the DCI format.

4. In paragraph 1, A method characterized in that the first time period is comprised of the sum of (i) a second time period during which the first cell triggers activation of the second cell and (ii) a third time period required for the second cell to transition from a sleep state to an activated state.

5. In paragraph 4, Information about the second time is included in the system information block, A method characterized in that information about the third time is included in the DCI format.

6. In paragraph 1, The above system information block includes identifiers of candidate cells including the second cell, A method characterized in that said candidate cells are associated with said data traffic.

7. A method performed by a base station associated with a first cell in a wireless communication system, A step of transmitting a system information block to a terminal in an RRC (radio resource control) idle or RRC inactive state, wherein the terminal is camped on the first cell; A step of transmitting a PDCCH (physical downlink control channel) including a DCI (downlink control information) format to the terminal, the DCI format including information for triggering activation of a second cell having data traffic to be transmitted to the terminal; and Comprising a step of transmitting information instructing activation to the second cell, A method, wherein a synchronization procedure to the second cell is performed a first time after the time at which the PDCCH is transmitted.

8. In paragraph 7, The CRC (cyclic redundancy check) of the above DCI format is scrambled with a P-RNTI (paging-radio network temporary identifier), and A method characterized in that it is determined whether a random access procedure is to be performed to the second cell based on a short message indicator field included in the DCI format.

9. In paragraph 7, A method characterized in that the first time period is comprised of the sum of (i) a second time period during which the first cell triggers activation of the second cell and (ii) a third time period required for the second cell to transition from a sleep state to an activated state.

10. In paragraph 9, Information about the second time is included in the system information block, A method characterized in that information about the third time is included in the DCI format.

11. In paragraph 7, The above system information block includes identifiers of candidate cells including the second cell, A method characterized in that said candidate cells are associated with said data traffic.

12. In a terminal in a wireless communication system, Transmitter and receiver; and A processor comprising: The terminal in the RRC (radio resource control) idle or RRC inactive state receives a system information block from the first cell on which it is camped, Receive a PDCCH (physical downlink control channel) including a DCI (downlink control information) format from the first cell, wherein the DCI format includes information for triggering activation of the second cell, After a first time from the time of receiving the above PDCCH, a synchronization procedure to the second cell is performed, and A terminal configured to receive data traffic from the second cell.

13. In paragraph 12, The processor is further configured to determine to perform a random access procedure to the second cell based on a short message indicator field included in the DCI format, A terminal characterized in that the CRC (cyclic redundancy check) of the above DCI format is scrambled with a P-RNTI (paging-radio network temporary identifier).

14. In paragraph 12, The first time is comprised of the sum of (i) a second time at which the first cell triggers the activation of the second cell and (ii) a third time required for the second cell to transition from a sleep state to an activated state, Information about the second time is included in the system information block, A terminal characterized in that information about the third time is included in the DCI format.

15. In a base station associated with a first cell in a wireless communication system, Transmitter and receiver; and A processor comprising: A system information block is transmitted to a terminal in an RRC (radio resource control) idle or RRC inactive state, and the terminal is camped on the first cell. Transmitting a PDCCH (physical downlink control channel) including a DCI (downlink control information) format to the terminal, wherein the DCI format includes information for triggering activation of a second cell having data traffic to be transmitted to the terminal, and is set to transmit information instructing activation to the second cell; A base station, wherein a synchronization procedure to the second cell is performed a first time after the time at which the above PDCCH is transmitted.

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