Method and device for reducing latency for ca in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. A method by which a user equipment (UE) transmits and receives a signal in a wireless communication system according to one embodiment of the present disclosure, may comprise the steps of: synchronizing with a first cell; receiving, from the first cell, a first control signal including information about a cell controllable by the first cell; and transmitting data to a second cell on the basis of the first control signal.

Description

Method and apparatus for reducing latency for CA in a wireless communication system

[0001] The present disclosure relates to a wireless communication system, and more specifically to a method and apparatus for reducing latency for CA in a wireless communication system.

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

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

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

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

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

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

[0008] The present disclosure relates to a method and apparatus for reducing latency for CA in a wireless communication system.

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

[0010] A method of a user equipment (UE) in a wireless communication system according to one embodiment of the present disclosure, in which a terminal transmits and receives a signal, may include the steps of synchronizing with a first cell, receiving from the first cell a first control signal including information about a cell controllable by the first cell, and transmitting data to a second cell based on the first control signal.

[0011] According to one embodiment of the present disclosure, by defining a signal transmission method of a base station in a wireless communication system, the delay time for CA is significantly reduced, enabling efficient resource utilization and reduced power consumption of the terminal.

[0012] The effects obtainable from the various embodiments of the present disclosure are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art based on the following detailed description.

[0013] The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. Additionally, the present disclosure provides a method and apparatus for reducing latency to reduce energy consumption of a base station in a mobile communication system. According to the present disclosure, the problem of excessive energy consumption of a base station in a mobile communication system can be resolved and high energy efficiency can be achieved.

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

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

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

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

[0018] FIG. 5 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.

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

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

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

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

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

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

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

[0026] FIG. 13 illustrates the configuration of a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

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

[0028] Figure 15 is a diagram showing the timeline from random access to SCell activity in the existing CA operation.

[0029] Figure 16 is a diagram showing the detailed timeline from the terminal receiving the SCell activation command in the existing CA to SCell activation.

[0030] Figure 17 is a diagram showing the timeline for fast SCell activation.

[0031] Figure 18a is a diagram showing the two octet structures of a trigger for MAC CE-based fast SCell activation.

[0032] Figure 18b is a diagram showing the two octet structures of a trigger for MAC CE-based fast SCell activation.

[0033] Figure 19 is a diagram of CA without delay time.

[0034] Figure 20 illustrates the procedure for receiving and measuring information about another cell for CA and establishing an RRC connection during the RA process.

[0035] FIG. 21 illustrates a terminal transceiver device according to one embodiment of the present disclosure.

[0036] FIG. 22 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0037] FIG. 23 is a block diagram of a base station according to one embodiment of the present disclosure.

[0038] For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description.

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in describing the present disclosure, if it is determined that a detailed description of related known functions or configurations might unnecessarily obscure the essence of the present disclosure, such detailed description will be omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0040] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, like reference numerals refer to like components.

[0041] At this point, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing instruction means to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0042] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specific logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For example, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order according to their corresponding functions.

[0043] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Thus, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and 'parts' may be implemented to utilize one or more CPUs within the device or secure multimedia card. Also, in the embodiments, 'parts' may include one or more processors.

[0044] In describing the present disclosure below, specific descriptions of related known functions or configurations will be omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the present disclosure. Embodiments of the present disclosure will be described below with reference to the attached drawings.

[0045] Terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, terms referring to various identification information, etc., are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms referring to objects having equivalent technical meanings may be used.

[0046] In the following description, the terms "physical channel" and "signal" may be used interchangeably with "data" or "control signal." For example, PDSCH (physical downlink shared channel) is a term referring to a physical channel through which data is transmitted, but PDSCH may also be used to refer to data. That is, in this disclosure, the expression "transmits a physical channel" may be interpreted as equivalent to the expression "transmits data or a signal through a physical channel."

[0047] In the present disclosure, upper layer signaling refers to a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel. Upper layer signaling may be understood as radio resource control (RRC) signaling or a media access control (MAC) control element (CE).

[0048] For convenience of explanation, the present disclosure uses terms and names defined in the 3GPP NR (New Radio: 5th generation mobile communication standard) specifications. However, the present disclosure is not limited by the above terms and names and may be applied equally to systems conforming to other standards. Additionally, the term "terminal" may refer to mobile phones, smartphones, IoT devices, sensors, as well as other wireless communication devices.

[0049] Hereinafter, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, eNB, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. The terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Of course, it is not limited to the above examples.

[0050] 5G (5 thInitial standards for the Generation) system or New Radio access technology (NR) have been completed. While existing mobile communication systems focused on conventional voice / data communication, 5G systems aim to satisfy various services and requirements, such as enhanced Mobile BroadBand (eMBB) services to improve existing voice / data communication, Ultra-Reliable and Low Latency Communication (URLLC) services, and massive Machine Type Communication (MTC) services to support mass communication of the Internet of Things.

[0051] While the transmission bandwidth per carrier in existing LTE and LTE-A is limited to a maximum of 20 MHz, 5G systems aim to provide ultra-high-speed data services reaching several Gbps by utilizing significantly wider ultra-wide bandwidth. Accordingly, 5G systems are considering ultra-high frequency bands ranging from several GHz to up to 100 GHz as candidate frequencies, where securing ultra-wide bandwidth frequencies is relatively easy. Additionally, it is possible to secure wide bandwidth frequencies for 5G systems through frequency reallocation or allocation from frequency bands ranging from several hundred MHz to several GHz currently used by existing mobile communication systems.

[0052] The above-mentioned radio waves in the ultra-high frequency band have wavelengths of several millimeters and are also called millimeter waves (mmWave). However, in the ultra-high frequency band, path loss of radio waves increases in proportion to the frequency band, and the coverage of mobile communication systems becomes smaller.

[0053] To overcome the disadvantage of reduced coverage in the aforementioned ultra-high frequency band, beamforming technology can be applied to increase the reach of radio waves by using multiple antennas to concentrate the radiated energy of the radio waves toward a predetermined target point. That is, a signal to which the beamforming technology is applied has a relatively narrow beam width, and as radiated energy is concentrated within this narrowed beam width, the reach of the radio waves is increased. The beamforming technology can be applied to both the transmitting end and the receiving end. In addition to the effect of increasing coverage, beamforming technology has the effect of reducing interference in areas outside the beamforming direction. For the beamforming technology to operate properly, accurate measurement and feedback methods for the transmit and receive beams are required. The beamforming technology can be applied to a control channel or data channel that corresponds one-to-one between a predetermined terminal and a base station. In addition, beamforming technology may be applied to common signals transmitted by a base station to multiple terminals within the system, such as synchronization signals, physical broadcast channels (PBCH), control channels for transmitting system information, and data channels, to increase coverage. When beamforming technology is applied to common signals, beam sweeping technology, which changes the beam direction to transmit the signal, is additionally applied to ensure that the common signal reaches terminals located at any position within the cell.

[0054] Another requirement for 5G systems is ultra-low latency services, where the transmission delay between the transmitter and receiver is approximately 1ms. As a measure to reduce transmission delay, it may be necessary to design a frame structure based on a short TTI (Transmission Time Interval) that is shorter than that of LTE and LTE-A. TTI is the basic time unit for performing scheduling, and the TTI of existing LTE and LTE-A systems can be 1ms, which corresponds to the length of one subframe. For example, to satisfy the requirements for ultra-low latency services in the 5G system, short TTIs such as 0.5ms, 0.25ms, or 0.125ms, which are shorter than those of existing LTE and LTE-A systems, may be possible.

[0055] 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 showing the basic structure of a time-frequency resource domain, which is a wireless resource domain where data or control channels of a 5G system are transmitted.

[0056] Referring to FIG. 1, the horizontal axis in FIG. 1 may represent the time domain, and the vertical axis may represent the frequency domain. The minimum transmission unit in the time domain of a 5G system is an OFDM (Orthogonal Frequency Division Multiplexing) symbol, (102) symbols are combined to form one slot (106), and A number of slots can be combined to form a single subframe (105). The length of the subframe is 1.0 ms, and 10 subframes can be combined to form a 10 ms frame (114). The minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the total system transmission bandwidth is a total It can be composed of (104) subcarriers.

[0057] In the time-frequency domain, the basic unit of a resource is a resource element (RE) (112), which can be represented by an OFDM symbol index and a subcarrier index. A resource block (RB or Physical Resource Block, PRB) is in the frequency domain. It can be defined as (110) consecutive subcarriers. In a 5G system And, the data rate can increase in proportion to the number of RBs scheduled to the terminal.

[0058] In a 5G system, base stations map data in RB units, and generally, scheduling can be performed on RBs that constitute one slot for a given terminal. That is, in a 5G system, the basic time unit for which scheduling is performed is a slot, and the basic frequency unit for which scheduling is performed can be an RB.

[0059] OFDM symbol count It is determined by the length of the cyclic prefix (CP) added to each symbol to prevent interference between symbols; for example, if a normal CP is applied , when Extended CP is applied Extended CP can be applied to systems with relatively longer transmission distances than standard CP, allowing orthogonality between symbols to be maintained. In the case of standard CP, the ratio of CP length to symbol length is maintained at a constant value, so the overhead caused by CP can remain constant regardless of the subcarrier spacing. That is, if the subcarrier spacing is small, the symbol length increases, and consequently, the CP length can also increase. Conversely, if the subcarrier spacing is large, the symbol length decreases, and consequently, the CP length can be reduced. The symbol length and CP length can be inversely proportional to the subcarrier spacing.

[0060] In 5G systems, various frame structures can be supported by adjusting the subcarrier spacing to satisfy diverse services and requirements. For example,

[0061] From the perspective of the operating frequency band, a larger subcarrier spacing may be advantageous for recovering phase noise in the high-frequency band.

[0062] - From the perspective of transmission time, a large subcarrier spacing shortens the symbol length in the time domain, and consequently shortens the slot length, which can be advantageous for supporting ultra-low latency services such as URLLC.

[0063] - From the perspective of cell size, a longer CP length allows for the support of larger cells, so a smaller subcarrier spacing allows for the support of relatively larger cells. In mobile communication, a cell can be a concept referring to an area covered by a single base station.

[0064] The aforementioned subcarrier spacing, CP length, etc., are essential information for OFDM transmission and reception; therefore, the base station and the terminal must recognize these values ​​as common to enable smooth transmission and reception. [Table 1] shows the subcarrier spacing configurations supported by 5G systems. ), subcarrier interval ( It can represent the relationship between the lengths of ), and CP.

[0065]

[0066] [Table 2] shows the subcarrier spacing settings for the standard CP ( ) By category, number of symbols per slot ( ), number of slots per frame ( ), number of slots per subframe ( It can represent ).

[0067]

[0068] [Table 3] shows the subcarrier spacing settings for extended CP ( ) By category, number of symbols per slot ( ), number of slots per frame ( ), number of slots per subframe ( It can represent ).

[0069]

[0070] In the early stages of introducing 5G systems, coexistence or dual-mode operation with at least existing LTE or / and LTE-A (hereinafter LTE / LTE-A) systems may be expected. This allows existing LTE / LTE-A to provide stable system operation to terminals, while the 5G system can perform the role of providing enhanced services to said terminals. Accordingly, the frame structure of the 5G system may include at least the frame structure or essential parameter set of LTE / LTE-A (subcarrier spacing = 15 kHz).

[0071] For example, subcarrier spacing setting In-frame structure (hereinafter Frame Structure A) and subcarrier spacing setting When comparing the in-frame structure (hereinafter frame structure B), compared to frame structure A, frame structure B can have the subcarrier spacing and RB size doubled, and the slot length and symbol length can be doubled. In the case of frame structure B, 2 slots can be configured into 1 subframe, and 20 subframes can be configured into 1 frame.

[0072] By generalizing the frame structure of the above 5G system, high scalability can be provided by ensuring that the essential parameter sets, such as subcarrier spacing, CP length, and slot length, have an integer multiple relationship with each other for each frame structure. Additionally, a subframe of a fixed length of 1ms can be defined to represent a reference time unit independent of the frame structure.

[0073] The above frame structure can be applied in response to various scenarios. From the perspective of cell size, since a longer CP length allows for the support of larger cells, the above frame structure A can support relatively larger cells compared to the above frame structure B. From the perspective of operating frequency band, since a larger subcarrier spacing is advantageous for recovering phase noise in the high-frequency band, the above frame structure B can support relatively higher operating frequencies compared to the above frame structure A. From the perspective of service, since a shorter slot length, which is the basic time unit of scheduling, is advantageous for supporting ultra-low latency services such as URLLC, the above frame structure B can be relatively more suitable for URLLC services compared to the above frame structure A.

[0074] In the following description of the present disclosure, an uplink (UL) refers to a wireless link through which a terminal transmits data or control signals to a base station, and a downlink (DL) may refer to a wireless link through which a base station transmits data or control signals to a terminal.

[0075] In the initial access phase, when the terminal first connects to the system, the terminal can synchronize downlink time and frequency from the synchronization signal transmitted by the base station through cell search and obtain a cell identifier (cell ID). Then, the terminal can use the obtained cell ID to receive a Physical Broadcast Channel (PBCH) and obtain a Master Information Block (MIB), which is essential system information, from the PBCH. Additionally, the terminal can receive a System Information Block (SIB) transmitted by the base station to obtain cell-common transmission and reception control information. The cell-common transmission and reception control information may include random access control information, paging control information, and common control information for various physical channels.

[0076] The synchronization signal serves as a reference for cell search, and subcarrier spacing can be applied for each frequency band to suit channel environments such as phase noise. In the case of data channels or control channels, as described above, subcarrier spacing may be applied differently depending on the service type to support various services.

[0077] FIG. 2 illustrates a time domain mapping structure and beam sweeping operation of a synchronization signal according to one embodiment of the present disclosure.

[0078] For the purpose of explanation, the following components may be defined.

[0079] - PSS (Primary Synchronization Signal): A signal that serves as the reference for DL ​​time / frequency synchronization and can provide some information about the cell ID.

[0080] - SSS (Secondary Synchronization Signal): Serves as a reference for DL ​​time / frequency synchronization and can provide some of the remaining information, including the cell ID. Additionally, it can serve as a reference signal for PBCH demodulation.

[0081] - PBCH (Physical Broadcast Channel): Can provide MIB (Master Information Block), which is essential system information required for the transmission and reception of the terminal's data channel and control channel. The said essential system information may include control information related to the search space representing wireless resource mapping information of the control channel, scheduling control information for a separate data channel transmitting system information, and information such as SFN (System Frame Number), which is a frame-unit index serving as a timing reference.

[0082] - SS / PBCH Block (Synchronization Signal / PBCH Block or SSB): An SS / PBCH block may consist of N OFDM symbols and may be composed of combinations such as PSS, SSS, and PBCH. In systems where beam sweeping technology is applied, the SS / PBCH block may be the minimum unit to which beam sweeping is applied. In a 5G system, N may be 4. A base station may transmit up to L SS / PBCH blocks, and the L SS / PBCH blocks may be mapped within a half frame (0.5ms). Additionally, the L SS / PBCH blocks may be repeated periodically in units of a predetermined period P. The base station may notify the terminal of the period P through signaling. If there is no separate signaling for the period P, the terminal may apply a pre-agreed default value.

[0083] FIG. 2 illustrates an example in which beam sweeping is applied in units of SS / PBCH blocks over time. Referring to FIG. 2, in the case of Terminal 1 (UE1) (205), at time t1 (S201), the SS / PBCH block can be received using a beam radiated in the direction of #d0 (203) by beamforming applied to SS / PBCH block #0. And Terminal 2 (UE2) (206) can be received 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, it may be difficult for Terminal 1 (UE1) (205) to obtain time / frequency synchronization and essential system information from an SS / PBCH block through a beam radiated in the direction of #d4, which is far from the location of Terminal 1.

[0084] In addition to the initial connection procedure described above, the terminal may also receive SS / PBCH blocks to determine whether the radio link quality of the current cell is maintained above a certain level. Furthermore, during the handover procedure in which the terminal moves the connection from the current cell to an adjacent cell, the terminal may receive SS / PBCH blocks of the adjacent cell to determine the radio link quality of the adjacent cell and to obtain time / frequency synchronization with the adjacent cell.

[0085] After the terminal obtains MIB and system information from the base station through the initial access procedure, the terminal may perform a random access procedure to switch the link with the base station to a connected state (connected state or RRC_CONNECTED state). Upon completion of the random access procedure, the terminal may switch to a connected state, and one-to-one communication between the base station and the terminal may become possible. The random access procedure can be described in detail below with reference to FIG. 3.

[0086] 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, but the present disclosure is not limited thereto. Furthermore, the present disclosure is not limited to the 4-step random access procedure exemplified in FIG. 3 and may also be applied to a 2-step random access procedure (transmission and reception of message A (a message containing information corresponding to message 1 and message 3) and transmission and reception of message B (a message containing information corresponding to message 2 and message 4)).

[0087] Referring to FIG. 3, as a first step (S310) of the random access procedure, a terminal (user equipment, UE) (S301) can transmit a random access preamble to a base station (302). The base station may include a gNB (next generation Node B). The random access preamble, which is the initial transmission message of the terminal in the random access procedure, may be referred to as message 1. The base station (302) can measure the transmission delay value between the terminal (301) and the base station (302) from the random access preamble and synchronize the uplink. At this time, the terminal (301) may arbitrarily select which random access preamble to use from a set of random access preambles given in advance by system information. And the initial transmission power of the random access preamble may be determined according to the path loss between the base station (302) and the terminal (301) measured by the terminal (301). Additionally, the terminal (301) can determine the transmission beam direction of the random access preamble from the synchronization signal received from the base station (302) and transmit the random access preamble.

[0088] In the second step (S320), the base station (302) transmits an uplink transmission timing control command to the terminal (301) based on the transmission delay value measured from the random access preamble received in the first step (S310). Additionally, the base station (302) may transmit uplink resource and power control commands to be used by the terminal (301) as scheduling information. The scheduling information may include control information for the uplink transmission beam of the terminal (301).

[0089] If the terminal (301) does not receive the Random Access Response (RAR) (or message 2), which is scheduling information for message 3, from the base station (302) within a predetermined time during the second step (S320), the first step (S310) may be performed again. If the first step (S310) is performed again, the terminal (301) can increase the probability of the base station (302) receiving the Random Access Preamble by increasing the transmission power of the Random Access Preamble by a predetermined step (power ramping).

[0090] In the third step (S330), the terminal (301) can transmit uplink data (message 3) including its terminal ID to the base station (302) via the uplink data channel (Physical Uplink Shared Channel, PUSCH) using the uplink resources allocated in the second step (S320). The transmission timing of the uplink data channel for transmitting Message 3 may follow the timing control command received from the base station (302) in the second step (S320). Additionally, 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 (302) in the second step (S320) and the power ramping value of the random access preamble. The uplink data channel for transmitting Message 3 may refer to the first uplink data signal transmitted by the terminal (301) to the base station (302) after the terminal transmits the random access preamble.

[0091] In the fourth step (S340), if the base station (302) determines that the terminal (301) has performed random access without collision with other terminals, it may transmit data (message 4) containing the ID of the terminal (301) that transmitted uplink data in the third step (S330) to the terminal (301). When the terminal (301) receives the signal transmitted by the base station (302) in the fourth step (S340) from the base station (302), it may determine that the random access was successful. Then, the terminal (301) may transmit HARQ-ACK information indicating whether the message 4 was successfully received to the base station (302) through the uplink control channel (Physical Uplink Control Channel, PUCCH).

[0092] If the data transmitted by the terminal (301) in the third step (S330) and the data of another terminal collide with each other, causing the base station (302) to fail to receive the data signal from the terminal (301), the base station (302) may not transmit any further data to the terminal (301). Accordingly, if the terminal (301) fails to receive the data transmitted from the base station (302) in the fourth step (S340) within a certain period of time, it is determined that the random access procedure has failed, and the process may restart from the first step (S310).

[0093] When the random access procedure is successfully completed, the terminal (301) is switched to a connected state, and one-to-one communication between the base station (302) and the terminal (301) may be possible. The base station (302) receives UE capability information from the terminal (301) in the connected state and can adjust scheduling by referring to the UE capability information of the terminal (301). Through the UE capability information, the terminal (301) can inform the base station (302) whether the terminal 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 (302) may be different values ​​for each terminal.

[0094] For example, the terminal (301) may report UE capability information to the base station, including at least a portion of the following control information as the UE capability information.

[0095] - Control information related to frequency bands supported by the terminal

[0096] - Control information related to channel bandwidth supported by the terminal

[0097] - Control information regarding the maximum modulation scheme supported by the terminal

[0098] - Control information regarding the maximum number of beams supported by the terminal

[0099] - Control information regarding the maximum number of layers supported by the terminal

[0100] - Control information related to CSI reporting supported by the terminal

[0101] - Control information on whether the terminal supports frequency hopping

[0102] - Bandwidth-related control information when Carrier Aggregation (CA) is supported

[0103] - Control information on whether cross-carrier scheduling is supported when carrier bundling is supported

[0104] FIG. 4 illustrates a procedure in which a terminal reports terminal capability (UE capability) information to a base station according to one embodiment of the present disclosure.

[0105] Referring to FIG. 4, at step S410, the base station (402) can send a UE capability information request message to the terminal (401). In response to the UE capability information request from the base station (402), the terminal can send UE capability information to the base station (402) at step S420.

[0106] Through the above process, the terminal (401) connected to the base station (402) is designated as a terminal (401) in the RRC_CONNECTED state, and the terminal (401) connected to the base station (402) can perform one-to-one communication. Conversely, a terminal that is not connected is in the RRC_IDLE state, and the operation of the terminal in that state can be distinguished as follows.

[0107] - Operates terminal-specific DRX (Discontinuous Reception) cycles set by the upper layer

[0108] - Operation of receiving paging messages from the core network

[0109] - Obtain system information

[0110] - Measurement operation and cell reselection related to surrounding cells

[0111] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed for the initial access of terminals. In addition to the operations performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following operations.

[0112] - Stores AS (Access stratum) information required for cell access

[0113] - Terminal-specific DRX cycle operation set by the RRC layer

[0114] - Configure RNA (RAN-based notification area) that can be utilized during handover by the RRC layer and perform periodic updates

[0115] - Monitoring RAN-based paging messages transmitted via I-RNTI

[0116] In the following, a scheduling method can be described in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data.

[0117] Downlink Control Information (DCI) is control information transmitted by a base station (402) to a terminal (401) via a downlink, and may include downlink data scheduling information or uplink data scheduling information for a specific terminal (401). Generally, the base station (402) may channel-code the DCI independently for each terminal and then transmit it to each terminal via a Physical Downlink Control Channel (PDCCH), which is a downlink physical control channel.

[0118] The base station (402) can operate by applying a predetermined DCI format according to the purpose, such as whether it is scheduling information for downlink data (Downlink assignment), whether it is scheduling information for uplink data (Uplink grant), and whether it is a DCI for power control, for a terminal to be scheduled.

[0119] The base station (402) can transmit downlink data to the terminal (401) through a physical downlink shared channel (PDSCH) for transmitting downlink data. Scheduling information, such as specific mapping locations in the time and frequency domains of the PDSCH, modulation methods, HARQ-related control information, and power control information, can be provided by the base station (402) to the terminal (401) through a DCI related to downlink data scheduling information among the DCIs transmitted through the PDSCH.

[0120] The terminal (401) can transmit uplink data to the base station (402) via a PUSCH (Physical Uplink Shared Channel), which is a physical channel for transmitting uplink data. Scheduling information, such as specific mapping locations in the time and frequency domains of the PUSCH, modulation schemes, HARQ-related control information, and power control information, can be provided by the base station (402) to the terminal (401) through a DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0121] 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.

[0122] Referring to FIG. 5, two control resource sets (control resource set #1 (501), control resource set #2 (502)) can be set within the terminal bandwidth part (UE bandwidth part) (510) on the frequency axis and one slot (520) on the time axis. The control resource sets (501, 502) can be set to a specific frequency resource (503) within the entire terminal bandwidth part (510) on the frequency axis. On the time axis, they can be set to one or more OFDM symbols, which can be defined as the control resource set duration (504).

[0123] 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.

[0124] A base station may configure one or more CORESETs for a terminal through upper-layer signaling (e.g., System Information, Master Information Block (MIB), Radio Resource Control (RRC) signaling). Configuring a CORESET for a terminal may mean providing information such as the CORESET identifier, the frequency location of the CORESET, and the symbol length of the CORESET. The information provided by the base station to the terminal to configure a CORESET may include at least some of the information included in [Table 4].

[0125]

[0126] CORESET in the frequency domain It can be composed of RBs, and in the time domain It can be composed of symbols. An NR PDCCH can be composed of one or more CCEs (Control Channel Elements). One CCE can be composed of six REGs (Resource Element Groups), and a REG can be defined as one RB during one OFDM symbol. Within a CORESET, REGs can be indexed in time-first order starting with REG index 0, beginning with the first OFDM symbol of the CORESET, the lowest RB.

[0127] Interleaved and non-interleaved methods may be supported as transmission methods for PDCCH. The base station may configure the terminal to perform interleaved or non-interleaved transmission for each CORESET through upper-layer signaling. Interleaving may be performed on a REG bundle basis. A REG bundle can be defined as a set of one or more REGs. Based on the interleaved or non-interleaved transmission configuration received from the base station, the terminal may determine the CCE-to-REG mapping method in the corresponding CORESET in the manner shown in [Table 5] below.

[0128]

[0129] The base station can inform the terminal of configuration information, such as which symbol the PDCCH is mapped to within the slot and the transmission period, through signaling.

[0130] FIG. 6 illustrates the mapping of DCI and DMRS in a REG, which is the basic unit of a downlink control channel according to one embodiment of the present disclosure.

[0131] Referring to FIG. 6, the basic unit of the downlink control channel, i.e., REG (603), may include both the REs to which DCI is mapped and the DMRS (605), which is a reference signal for decoding, to which it is mapped. Additionally, three DMRS (605) may be transmitted within one REG (603).

[0132] The search space of a PDCCH can be described below. The number of CCEs required to transmit a PDCCH can be 1, 2, 4, 8, or 16 depending on the Aggregation Level (AL), and different numbers of CCEs can be used for link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel can be transmitted through L CCEs. The terminal performs blind decoding to detect signals without knowing information about the downlink control channel, 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 terminal must attempt to decode at a given aggregation level, and since there are various aggregation levels that form a group of 1, 2, 4, 8, or 16 CCEs, the terminal may have multiple search spaces. A Search Space Set can be defined as a set of search spaces at all established aggregation levels.

[0133] Search spaces can be classified into Common Search Spaces (CSS) and UE-specific Search Spaces (USS). A certain group of terminals or all terminals may examine the Common Search Space of a PDCCH to receive cell-common control information, such as dynamic scheduling or paging messages for System Information Blocks (SIBs). For example, a terminal may receive scheduling allocation information for a PDSCH for receiving system information by examining the Common Search Space of the PDCCH. In the case of the Common Search Space, since a certain group of terminals or all terminals must receive the PDCCH, it may be defined as a pre-agreed set of CCEs. Scheduling allocation information for a UE-specific PDSCH or PUSCH may be received by a terminal by examining the UE-specific Search Space of the PDCCH. The UE-specific Search Space may be defined specifically as a function of the terminal's ID (Identity) and various system parameters.

[0134] The base station can configure configuration information for the search space of the PDCCH to the terminal through upper-layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station can configure the number of PDCCH candidates at each aggregation level L, the monitoring period for the search space, the occasion for monitoring in slot-symbol units for the search space, the search space type (common search space or terminal-specific search space), the combination of DCI format and RNTI to be monitored in the search space, and the CORESET index to be monitored for the search space to the terminal. For example, parameters for the search space of the PDCCH may include information such as [Table 6] below.

[0135]

[0136]

[0137]

[0138]

[0139] Depending on the configuration information, the base station may set one or more sets of search spaces for the terminal. According to some embodiments, the base station may set search space set 1 and search space set 2 for the terminal. In search space set 1, the terminal may be configured to monitor DCI format A scrambled with X-RNTI in a common search space, and in search space set 2, the terminal may be configured to monitor DCI format B scrambled with Y-RNTI in a terminal-specific search space.

[0140] According to the configuration information, one or more sets of search spaces may exist in a common search space or a terminal-specific search space. For example, Search Space Set #1 and Search Space Set #2 may be configured as a common search space, and Search Space Set #3 and Search Space Set #4 may be configured as a terminal-specific search space.

[0141] In the common search space, terminals can monitor the following combinations of DCI formats and RNTI. Of course, they are not limited to the following examples.

[0142] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0143] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0144] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0145] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0146] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0147] - DCI format 2_4 with CRC scrambled by CI-RNTI

[0148] - DCI format 2_5 with CRC scrambled by AI-RNTI

[0149] - DCI format 2_6 with CRC scrambled by PS-RNTI

[0150] - DCI format 2_7 with CRC scrambled by PEI-RNTI

[0151] Terminal - In a specific search space, the terminal can monitor the following combinations of DCI formats and RNTI. Of course, it is not limited to the following examples.

[0152] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0153] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0154] The above RNTIs may follow the following definitions and uses.

[0155] C-RNTI (Cell RNTI): Used for terminal-specific PDSCH or PUSCH scheduling

[0156] TC-RNTI (Temporary Cell RNTI): Used for terminal-specific PDSCH scheduling

[0157] CS-RNTI (Configured Scheduling RNTI): Used for semi-statically configured terminal-specific PDSCH scheduling.

[0158] RA-RNTI (Random Access RNTI): Used for PDSCH scheduling during the random access phase

[0159] P-RNTI (Paging RNTI): Used for PDSCH scheduling where paging is transmitted.

[0160] SI-RNTI (System Information RNTI): Used for PDSCH scheduling where system information is transmitted.

[0161] INT-RNTI (Interruption RNTI): Used to indicate whether PDSCH is pucturing.

[0162] TPC-PUSCH-RNTI (Transmit Power Control for PUSCH RNTI): Used to instruct power control commands to the PUSCH

[0163] TPC-PUCCH-RNTI (Transmit Power Control for PUCCH RNTI): Used to instruct power control commands to the PUCCH

[0164] TPC-SRS-RNTI (Transmit Power Control for SRS RNTI): Used to instruct power regulation commands to the SRS

[0165] The DCI formats described above may follow the definitions in [Table 7] below.

[0166]

[0167] In CORESET p and search space set s, the search space of aggregate level L can be expressed as follows:

[0168]

[0169]

[0170] The value may be 0 for the common search space.

[0171] In the case of a terminal-specific search space, the value may correspond to a value that changes according to the terminal's ID (C-RNTI or the ID set for the terminal by the base station) and the time index.

[0172] In the following, we can specifically explain how to set the TCI state for the PDCCH (or PDCCH DMRS) in a 5G communication system.

[0173] A base station may be able to set and indicate a TCI state for a PDCCH (or PDCCH DMRS) through appropriate signaling. According to the above description, a base station may be able to set and indicate a TCI state for a PDCCH (or PDCCH DMRS) through appropriate signaling. The TCI state is intended to announce a Quasi-Co-location (QCL) relationship between a PDCCH (or PDCCH DMRS) and another RS ​​or channel. When a reference antenna port A (reference RS #A) and another target antenna port B (target RS #B) are QCLed with each other, it may mean that the terminal is allowed to apply some or all of the large-scale channel parameters estimated from the antenna port A to channel measurements from the antenna port B. QCL may require associating different parameters depending on the situation, such as 1) time tracking affected by average delay and delay spread, 2) frequency tracking affected by Doppler shift and Doppler spread, 3) RRM (radio resource management) affected by average gain, and 4) BM (beam management) affected by spatial parameters. Accordingly, NR can support four types of QCL relationships as shown in Table 8 below.

[0174]

[0175] 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.

[0176] The above QCL relationship may be configured for the terminal through the RRC parameter TCI-State and QCL-Info as shown in Table 9 below. Referring to Table 9, the base station may configure one or more TCI states for the terminal and provide up to two QCL relationships (qcl-Type1, qcl-Type2) for the RS that references the ID of the TCI state, i.e., the target RS. At this time, each QCL information (QCL-Info) included in each of the above TCI states may include the serving cell index and BWP index of the reference RS pointed to by the QCL information, the type and ID of the reference RS, and the QCL type as shown in Table 8 above.

[0177]

[0178] FIG. 7 illustrates base station beam allocation according to TCI state setting according to one embodiment of the present disclosure.

[0179] Referring to FIG. 7, the base station can transmit information about N different beams to the terminal through N different TCI states. For example, when N=3, the base station can notify that antenna ports referencing the different TCI states 700, 705, or 710 are associated with different spatial Rx parameters, i.e., different beams, by setting the qcl-Type2 parameters included in the three TCI states (700, 705, 710) to be associated with CSI-RS or SSB corresponding to different beams and set to QCL type D.

[0180] Specifically, the TCI state combinations applicable to the PDCCH DMRS antenna port may be as shown in Table 10 below. The fourth row of Table 10 represents the combinations assumed by the terminal before RRC setup, and setup after RRC may not be possible.

[0181]

[0182] NR supports a hierarchical signaling method as shown in Fig. 8 for dynamic allocation of PDCCH beams.

[0183] FIG. 8 illustrates a hierarchical signaling method for dynamic allocation of a PDCCH beam of NR according to one embodiment of the present disclosure.

[0184] Referring to FIG. 8, the base station can set N TCI states (805, 810, ..., 820) to the terminal through RRC signaling (800), and some of these can be set as TCI states for CORESET (825). Subsequently, the base station can instruct the terminal to one of the TCI states for CORESET (830, 835, 840) through MAC CE signaling (845). Subsequently, the terminal can receive PDCCH based on beam information included in the TCI state indicated by the MAC CE signaling.

[0185] FIG. 9 illustrates a TCI indication MAC CE signaling structure for a PDCCH DMRS according to one embodiment of the present disclosure.

[0186] Referring to FIG. 9, the TCI indication MAC CE signaling for the PDCCH DMRS is composed of 2 bytes (16 bits) and may include a 1-bit reserved bit (910), a 5-bit serving cell ID (915), a 2-bit BWP ID (920), a 2-bit CORESET ID (925), and a 6-bit TCI state ID (930).

[0187] A base station may indicate one of the TCI state lists included in the CORESET configuration through MAC CE signaling. Until another TCI state is indicated to the CORESET through another MAC CE signaling, the terminal may consider that the same QCL information applies to all one or more search spaces connected to the CORESET.

[0188] The PDCCH beam allocation method described above has the disadvantage that it is difficult to instruct beam changes faster than the MAC CE signaling delay, and that the same beam is applied uniformly to all CORESETs regardless of search space characteristics, which may make flexible PDCCH beam operation difficult. The embodiments of the present disclosure below can provide a more flexible method for setting and operating PDCCH beams. In describing the embodiments of the present disclosure below, several distinct examples are provided for convenience of explanation, but these are not mutually exclusive and can be appropriately combined and applied depending on the situation.

[0189] The base station may set one or more TCI states for a specific control resource set for the terminal, and may activate one of the set TCI states through a MAC CE activation command. For example, if {TCI state#0, TCI state#1, TCI state#2} are set as TCI states for control resource set #1, the base station may transmit a command to the terminal via MAC CE to activate TCI state#0 as the TCI state for control resource set #1. Based on the activation command for the TCI state received via MAC CE, the terminal can correctly receive the DMRS of the corresponding control resource set based on the QCL information within the activated TCI state.

[0190] For a control resource set (control resource set #0) with an index set to 0, if the terminal has not received a MAC CE activation command for the TCI state of control resource set #0, it can be assumed that the terminal has QCL with the SS / PBCH block identified in the initial connection process or the non-contention-based random access process that was not triggered by the PDCCH command for the DMRS transmitted from control resource set #0.

[0191] For a control resource set (control resource set #X) with an index set to a value other than 0, if the terminal has not received a TCI state for control resource set #X, or has received one or more TCI states but has not received a MAC CE activation command to activate one of them, it can be assumed that the terminal has QCL with the SS / PBCH block identified during the initial connection process for the DMRS transmitted from control resource set #X.

[0192] Next, we can specifically explain Downlink Control Information (DCI) in a 5G system.

[0193] In a 5G system, scheduling information for uplink data (or Physical Uplink Shared Channel (PUSCH)) or downlink data (or Physical Downlink Shared Channel (PDSCH)) can be transmitted from a base station to a terminal via DCI. The terminal can monitor the fallback DCI format and the non-fallback DCI format for PUSCH or PDSCH. The fallback DCI format may consist of fixed fields selected between the base station and the terminal, and the non-fallback DCI format may include configurable fields.

[0194] DCI can be transmitted through the Physical Downlink Control Channel (PDCCH) after undergoing channel coding and modulation processes. A Cyclic Redundancy Check (CRC) is attached to the DCI message payload, and the CRC can be scrambled into a Radio Network Temporary Identifier (RNTI) corresponding to the terminal's identity. Different RNTIs may be used depending on the purpose of the DCI message, such as UE-specific data transmission, power control commands, or random access responses. In other words, the RNTI is not transmitted explicitly but is included in the CRC calculation process. Upon receiving a DCI message transmitted over the PDCCH, the terminal checks the CRC using the assigned RNTI; if the CRC check result is correct, the terminal knows that the message has been transmitted to it.

[0195] For example, a DCI scheduling a PDSCH for System Information (SI) can be scrambled to SI-RNTI. A DCI scheduling a PDSCH for Random Access Response (RAR) messages can be scrambled to RA-RNTI. A DCI scheduling a PDSCH for Paging messages can be scrambled to P-RNTI. A DCI notifying a Slot Format Indicator (SFI) can be scrambled to SFI-RNTI. A DCI notifying Transmit Power Control (TPC) can be scrambled to TPC-RNTI. A DCI scheduling a terminal-specific PDSCH or PUSCH can be scrambled to C-RNTI (Cell RNTI).

[0196] DCI format 0_0 can be used as a countermeasure DCI for scheduling PUSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 0_0 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 11.

[0197]

[0198]

[0199]

[0200]

[0201] DCI format 0_1 ​​can be used as a non-defense DCI for scheduling PUSCH, whereby the CRC can be scrambled with C-RNTI. DCI format 0_1 ​​with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 12.

[0202]

[0203]

[0204]

[0205]

[0206]

[0207]

[0208]

[0209]

[0210]

[0211]

[0212]

[0213] DCI format 1_0 can be used as a countermeasure DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_0 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 13.

[0214]

[0215]

[0216]

[0217]

[0218]

[0219] DCI format 1_1 can be used as a non-defense DCI for scheduling PDSCH, whereby the CRC can be scrambled with C-RNTI. DCI format 1_1 with the CRC scrambled with C-RNTI may include the following information, for example, as shown in Table 14.

[0220]

[0221]

[0222]

[0223]

[0224]

[0225]

[0226]

[0227]

[0228]

[0229]

[0230]

[0231]

[0232]

[0233]

[0234] In the following, we can describe the time domain resource allocation method for data channels in a 5G communication system.

[0235] The base station may set a table for time-domain resource allocation information for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH) for the terminal using upper-layer signaling (e.g., RRC signaling). For PDSCH, a table consisting of a maximum of maxNrofDL-Allocations = 16 entries may be set, and for PUSCH, a table consisting of a maximum of maxNrofUL-Allocations = 16 entries may be set. For example, time domain resource allocation information may include PDCCH-to-PDSCH slot timing (corresponding to a slot-unit time interval between the time when the PDCCH is received and the time when the PDSCH scheduled by the received PDCCH is transmitted, denoted as K0) or PDCCH-to-PUSCH slot timing (corresponding to a slot-unit time interval between the time when the PDCCH is received and the time when the PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), information on the position and length of the start symbol for which the PDSCH or PUSCH is scheduled within the slot, and the mapping type of the PDSCH or PUSCH. For example, information such as that shown in Tables 15 and 16 below may be notified from the base station to the terminal.

[0236]

[0237]

[0238] The base station may notify the terminal of one of the entries in the table for the time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., by indicating the 'time domain resource allocation' field within the DCI). The terminal may obtain time domain resource allocation information for PDSCH or PUSCH based on the DCI received from the base station.

[0239] In the following, we can describe the frequency domain resource allocation method for data channels in a 5G communication system.

[0240] In 5G, two types, resource allocation type 0 and resource allocation type 1, can be supported as a method of indicating frequency domain resource allocation information for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH).

[0241] Resource allocation type 0

[0242] RB allocation information may be notified from the base station to the terminal in the form of a bitmap for the RBG (Resource Block Group). In this case, the RBG may be composed of a set of consecutive VRBs (Virtual RBs), and the size P of the RBG may be determined based on the value set by the upper layer parameter (rbg-Size) and the size value of the bandwidth part defined in Table 17 below.

[0243]

[0244] - Size Total number of RGBs in bandwidth part i ( ) can be defined as follows.

[0245]

[0246] - Each bit of a bitmap of bit size can correspond to a respective RGB. The RGBs can be indexed in increasing order of frequency, starting from the lowest frequency position in the bandwidth part. Within the bandwidth part For the RBGs, from RBG#0 to RBG#( ) can be mapped from the MSB to the LSB of the RGB bitmap. The terminal can determine that the RGB corresponding to the bit value is assigned when the specific bit value in the bitmap is 1, and can determine that the RGB corresponding to the bit value is not assigned when the specific bit value in the bitmap is 0.

[0247] Resource Allocation Type 1

[0248] - RB allocation information can be notified from the base station to the terminal as information regarding the starting position and length of consecutively allocated VRBs. In this case, interleaving or non-interleaving may be additionally applied to the consecutively allocated VRBs. The resource allocation field of Resource Allocation Type 1 may be composed of a Resource Indication Value (RIV), and the RIV is the starting point of the VRB ( ) and the length of consecutively allocated RB ( It can be composed of. More specifically, The RIV within the bandwidth part of the size can be defined as follows.

[0249]

[0250] A base station may semi-statically configure time and frequency transmission resources and various transmit / receive parameters for the Physical Downlink Shared Channel (PDSCH) and the Physical Uplink Shared Channel (PUSCH) for the purpose of supporting unauthorized-based transmission and reception for the terminal.

[0251] To explain it more specifically, it can be as follows.

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

[0253]

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

[0255] In 5G, two types of non-authorization-based transmission methods (named Configured Grant, Grant free, etc.) for the uplink data channel (PUSCH) can be supported (Type-1 PUSCH transmission with a configured grant, Type-2 PUSCH transmission with a configured grant).

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

[0257] In unauthorized-based PUSCH transmission type-1, the base station may set a specific time / frequency resource (600) that allows unauthorized-based PUSCH transmission to the terminal as upper-layer signaling, such as RRC signaling. For example, as illustrated in FIG. 6, time-axis allocation information (601), frequency-axis allocation information (602), period information (603), etc. for the resource (600) may be set. In addition, the base station may set various parameters for PUSCH transmission to the terminal (e.g., frequency hopping, DMRS settings, MCS table, MCS, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), etc.) as upper-layer signaling. More specifically, the setting information in Table 19 below may be included.

[0258]

[0259]

[0260]

[0261]

[0262]

[0263]

[0264]

[0265] When the terminal receives configuration information for unauthorized-based PUSCH transmission type-1 from the base station, the terminal may transmit PUSCH without authorization from the base station using a periodically configured resource (600). Various parameters required to transmit PUSCH (e.g., frequency hopping, DMRS configuration, MCS, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), number of precoding and layers, antenna port, frequency hopping offset, etc.) may all follow the configuration values ​​notified by the base station.

[0266] Non-acknowledgment-based PUSCH transmission type-2

[0267] In unauthorized-based PUSCH transmission type-2, the base station may set some of the information regarding specific time / frequency resources (600) that allow unauthorized-based PUSCH transmission to the terminal (e.g., period information (603), etc.) as upper-layer signaling (e.g., RRC signaling). Additionally, the base station may set various parameters for PUSCH transmission to the terminal (e.g., frequency hopping, DMRS settings, MCS table, RBG (Resource Block Group) size, number of repeated transmissions, RV (Redundancy Version), etc.) as upper-layer signaling. More specifically, the base station may set the configuration information of Table 20 below to the terminal as upper-layer signaling.

[0268]

[0269]

[0270]

[0271]

[0272] The base station may transmit a DCI composed of specific DCI field values ​​to the terminal for the purpose of activating or releasing scheduling for DL ​​SPS and UL grant Type 2.

[0273] To explain in more detail, it is as follows.

[0274] The base station can configure CS-RNTI (Configured Scheduling-RNTI) for the terminal, and the terminal can monitor a DCI format in which the CRC is scrambled with CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 21 below, the terminal may regard the DCI as a command to enable transmission and reception for DL ​​SPS or UL grant Type 2.

[0275]

[0276] The base station can configure CS-RNTI (Configured Scheduling-RNTI) for the terminal, and the terminal can monitor a DCI format in which the CRC is scrambled with CS-RNTI. If the CRC of the DCI format received by the terminal is scrambled with CS-RNTI, the New Data Indicator (NDI) is set to '0', and the DCI field satisfies Table 22 below, the terminal may regard the DCI as a command to release transmission and reception for DL ​​SPS or UL grant Type 2.

[0277]

[0278] The DCI instructing the release for the above DL SPS or UL grant Type 2 follows a DCI format corresponding to DCI format 0_0 or DCI format 1_0, and since DCI format 0_0 or 1_0 does not include a Carrier Indicator Field (CIF), the terminal may always need to monitor the PDCCH in the cell where the DL SPS or UL grant Type 2 is set in order to receive a release command for the DL SPS or UL grant Type 2 for a specific cell. Even if a specific cell is set to cross-carrier scheduling, the terminal may always need to monitor DCI format 1_0 or DCI format 0_0 in that cell to receive a release command for the DL SPS or UL grant Type 2 set in that cell.

[0279] In the following, carrier aggregation and scheduling methods in 5G communication systems can be explained in detail.

[0280] A terminal can receive multiple cells (Cell or CC (Component Carrier)) from a base station and can receive a setting regarding whether cross-carrier scheduling is enabled for the cells configured in the terminal. If cross-carrier scheduling is enabled for a specific cell (Cell A, Scheduled Cell), PDCCH monitoring for Cell A is not performed at Cell A but can be performed at another cell (Cell B, Scheduling Cell) designated for cross-carrier scheduling. In this case, the Scheduled Cell (Cell A) and the Scheduling Cell (Cell B) can be configured with different numerologies. Here, the numerology may include subcarrier spacing, cyclic prefix, etc. When the numerologies of cell A and cell B are different, when cell B's PDCCH schedules cell A's PDSCH, a minimum scheduling offset as follows may be additionally considered between PDCCH and PDSCH.

[0281] Cross-Carrier Scheduling Method

[0282] ◆ Subcarrier spacing of Cell B ( ) is the subcarrier spacing of cell A ( If it is less than ), the PDSCH can be scheduled starting from the next PDSCH slot corresponding to X symbols after the last symbol of the PDCCH received from Cell B. Here, X is It may vary depending on, When X=4 symbols, When X=4 symbols, When that, X can be defined as a symbol of 8.

[0283] ◆ Subcarrier spacing of Cell B ( ) is the subcarrier spacing of cell A ( If it is greater than ), the PDSCH can be scheduled starting from a point X symbols after the last symbol of the PDCCH received by Cell B. Here, X is It may vary depending on, When X=4 symbols, When X=8 symbols, When X=12, it can be defined as a symbol.

[0284] The rate matching and puncturing operations can be described in detail below.

[0285] When a time and frequency resource A intended to transmit an arbitrary symbol sequence A overlaps with an arbitrary time and frequency resource B, rate matching or puncturing operations may be considered as transmission and reception operations of channel A, taking into account the area resource C where resource A and resource B overlap. Specific operations may follow the details below.

[0286] Rate Matching Operation

[0287] - A base station may transmit a symbol sequence A to a terminal by mapping Channel A only to the remaining resource area, excluding Resource C which corresponds to the area overlapping with Resource B, from the entire Resource A. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol 4}, Resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and Resource B is {Resource #3, Resource #5}, the base station may sequentially map and send symbol sequence A to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3} which corresponds to Resource C within Resource A. Consequently, the base station may transmit the symbol sequence {Symbol #1, Symbol #2, Symbol #3} by mapping it to {Resource #1, Resource #2, Resource #4}, respectively.

[0288] The terminal can determine Resource A and Resource B from scheduling information regarding Symbol Sequence A from the base station, and thereby determine Resource C, which is the area where Resource A and Resource B overlap. The terminal can receive Symbol Sequence A by assuming that Symbol Sequence A was transmitted by mapping it to the remaining area of ​​Resource A, excluding Resource C. For example, if Symbol Sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol 4}, Resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and Resource B is {Resource #3, Resource #5}, the terminal can receive Symbol Sequence A by assuming that it was sequentially mapped to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3}, which corresponds to Resource C. Consequently, the terminal can perform a series of subsequent reception operations by assuming that Symbol Sequence {Symbol #1, Symbol #2, Symbol #3} was transmitted by mapping it to {Resource #1, Resource #2, Resource #4}, respectively.

[0289] Puncturing action

[0290] If there is a resource C corresponding to an area overlapping with resource B among all resources A to which the base station intends to transmit symbol sequence A to a terminal, the base station maps symbol sequence A to the entire resource A, but does not perform transmission in the resource area corresponding to resource C, and can perform transmission only in the remaining resource area of ​​resource A excluding resource C. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol #4}, resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and resource B is {Resource #3, Resource #5}, the base station can map symbol sequence A {Symbol #1, Symbol #2, Symbol #3, Symbol #4} to resource A {Resource #1, Resource #2, Resource #3, Resource #4} respectively, and can transmit only the symbol sequence {Symbol #1, Symbol #2, Symbol #4} corresponding to the remaining resources {Resource #1, Resource #2, Resource #4}, excluding {Resource #3} corresponding to resource C, and may not transmit {Symbol #3} mapped to {Resource #3} corresponding to resource C. Consequently, the base station can map and transmit the symbol sequence {Symbol #1, Symbol #2, Symbol #4} to {Resource #1, Resource #2, Resource #4} respectively.

[0291] The terminal can determine resources A and B from scheduling information for symbol sequence A from the base station, and thereby determine resource C, which is the area where resources A and B overlap. The terminal can receive symbol sequence A by assuming that symbol sequence A is mapped to the entire resource A, but is transmitted only in the remaining area of ​​resource A excluding resource C. For example, if symbol sequence A consists of {Symbol #1, Symbol #2, Symbol #3, Symbol #4}, resource A is {Resource #1, Resource #2, Resource #3, Resource #4}, and resource B is {Resource #3, Resource #5}, the terminal can assume that symbol sequence A {Symbol #1, Symbol #2, Symbol #3, Symbol #4} is mapped to resource A {Resource #1, Resource #2, Resource #3, Resource #4} respectively, but {Symbol #3} mapped to {Resource #3} corresponding to resource C is not transmitted, and can receive by assuming that symbol sequence {Symbol #1, Symbol #2, Symbol #4} corresponding to the remaining resources {Resource #1, Resource #2, Resource #4}—excluding {Resource #3} corresponding to resource C—is mapped and transmitted. Consequently, the terminal can perform a subsequent series of receiving operations by assuming that the symbol sequence {Symbol #1, Symbol #2, Symbol #4} has been transmitted and mapped to {Resource #1, Resource #2, Resource #4}, respectively.

[0292] FIG. 10 is a diagram illustrating a method for transmitting and receiving data by a base station and a terminal in consideration of a downlink data channel and rate matching resources according to one embodiment of the present disclosure.

[0293] Referring to FIG. 10, a downlink data channel (PDSCH, 1001) and a rate matching resource (1002) may be illustrated. FIG. 10 may include slot #0 (1006), slot #1 (1007), or slot #2 (1008). A base station may set one or more rate matching resources (1002) to a terminal through upper layer signaling (e.g., RRC signaling). The rate matching resource (1002) setting information may include time-axis resource allocation information (1003), frequency-axis resource allocation information (1004), and period information (1005). In the following, a bitmap corresponding to the frequency-axis resource allocation information (1004) may be named "first bitmap," a bitmap corresponding to the time-axis resource allocation information (1003) may be named "second bitmap," and a bitmap corresponding to the period information (1005) may be named "third bitmap." If all or part of the time and frequency resources of a scheduled data channel (1001) overlap with a set rate matching resource (1002), the base station can transmit the data channel (1001) by rate matching it in the rate matching resource (1002) portion, and the terminal can perform reception and decoding after assuming that the data channel (1001) is rate matched in the rate matching resource (1002) portion.

[0294] The base station can dynamically notify the terminal via DCI whether to rate match a data channel in the above-mentioned rate matching resource portion through additional settings (corresponding to the "rate matching indicator" within the aforementioned DCI format). Specifically, the base station can select some of the above-mentioned rate matching resources and group them into rate matching resource groups, and can indicate to the terminal via DCI using a bitmap method whether to rate match a data channel for each rate matching resource group. For example, if four rate matching resources, RMR#1, RMR#2, RMR#3, and RMR#4, are set, the base station can set RMG#1={RMR#1, RMR#2} and RMG#2={RMR#3, RMR#4} as rate matching groups, and can indicate to the terminal via a bitmap whether to rate match in RMG#1 and RMG#2, respectively, using 2 bits within the DCI field. For example, the base station can instruct the terminal to "1" if rate matching is required, and "0" if rate matching is not required.

[0295] In 5G, granularity of "RB symbol level" and "RE level" can be supported by setting the aforementioned rate matching resources to the terminal. More specifically, the following setting method can be followed.

[0296] RB symbol level

[0297] The terminal can receive up to four RateMatchPatterns as upper layer signaling per bandwidth part, and one RateMatchPattern may include the following contents.

[0298] - As a Reserved Resource within the Bandwidth Part, a resource may be included in which the time and frequency resource domains of the said Reserve Resource are set as a combination of an RB level bitmap and a symbol level bitmap along the frequency axis. The said Reserve Resource may span across one or two slots. A time domain pattern (periodicityAndPattern) in which the time and frequency domains composed of each RB level and symbol level bitmap pair are repeated may be additionally set.

[0299] - It may include time and frequency domain resource areas set as control resource sets within the bandwidth part, and resource areas corresponding to time domain patterns set as search space settings where the resource areas are repeated.

[0300] RE level

[0301] The terminal can receive the following settings through upper-layer signaling.

[0302] - Configuration information for an RE corresponding to an LTE CRS (Cell-specific Reference Signal or Common Reference Signal) pattern (lte-CRS-ToMatchAround) may include the number of ports of the LTE CRS (nrofCRS-Ports) and the LTE-CRS-vshift(s) value (v-shift), the location information of the LTE carrier's center subcarrier (carrierFreqDL) from a reference frequency point (e.g., reference point A), the LTE carrier's bandwidth size (carrierBandwidthDL) information, and subframe configuration information corresponding to a Multiast-broadcast single-frequency network (mbsfn-SubframConfigList). Based on the aforementioned information, the terminal can determine the location of the CRS within an NR slot corresponding to an LTE subframe.

[0303] - It may include configuration information for resource sets corresponding to one or more ZP (Zero Power) CSI-RS within the bandwidth part.

[0304] The following describes in detail how to measure and report channel status in a 5G communication system.

[0305] Channel state information (CSI) may include channel quality information (CQI), precoding matrix index (PMI), CSI-RS resource indicator (CRI), SS / PBCH block resource indicator (SSSBRI), layer indicator (LI), rank indicator (RI), and / or L1-RSRP (Reference Signal Received Power). The base station may control time and frequency resources for the aforementioned CSI measurement and reporting of the terminal.

[0306] For the aforementioned CSI measurement and reporting, the terminal can receive setting information for N (≥1) CSI reports (CSI-ReportConfig), setting information for M (≥1) RS transmission resources (CSI-ResourceConfig), and one or two trigger state lists (CSI-AperiodicTriggerStateList, CSI-SemiPersistentOnPUSCH-TriggerStateList) through upper layer signaling.

[0307] The setting information for the aforementioned CSI measurement and reporting may be more specifically as described in Tables 23 to 29 below.

[0308] The IE CSI-ReportConfig is used to configure a periodic or semi-persistent report sent on PUCCH on the cell in which the CSI-ReportConfig is included, or to configure a semi-persistent or aperiodic report sent on PUSCH triggered by DCI received on the cell in which the CSI-ReportConfig is included (in this case, the cell on which the report is sent is determined by the received DCI). See TS 38.214

[0019] , clause 5.2.1.

[0309]

[0310]

[0311]

[0312]

[0313]

[0314]

[0315]

[0316]

[0317]

[0318] The IE NZP-CSI-RS-ResourceSet is a set of Non-Zero-Power (NZP) CSI-RS resources (their IDs) and set-specific parameters.

[0319]

[0320]

[0321] The IE CSI-SSB-ResourceSet is used to configure one SS / PBCH block resource set which refers to SS / PBCH as indicated in ServingCellConfigCommon.

[0322]

[0323]

[0324] The IE CSI-IM-ResourceSet is used to configure a set of one or more CSI Interference Management (IM) resources (their IDs) and set-specific parameters.

[0325]

[0326] The CSI-AperiodicTriggerStateList IE is used to configure the UE with a list of aperiodic trigger states. Each codepoint of the DCI field "CSI request" is associated with one trigger state. Upon reception of the value associated with a trigger state, the UE will perform measurement of CSI-RS (reference signals) and aperiodic reporting on L1 according to all entries in the associatedReportConfigInfoList for that trigger state.

[0327]

[0328]

[0329] The CSI-SemiPersistentOnPUSCH-TriggerStateList IE is used to configure the UE with list of trigger states for semi-persistent reporting of channel state information on L1. See also TS 38.214

[0019] , clause 5.2.

[0330]

[0331] Regarding the aforementioned CSI report settings (CSI-ReportConfig), each report setting CSI-ReportConfig may be associated with a single downlink (DL) bandwidth portion identified by the upper-layer parameter bandwidth portion identifier (bwp-id) given by the CSI-ResourceConfig, which is associated with the corresponding report setting. As for the time domain reporting operation for each report setting CSI-ReportConfig, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, and this can be configured from the base station to the terminal by the reportConfigType parameter set from the upper layer. The semi-persistent CSI reporting method may support 'PUCCH-based semi-persistent (semi-PersistentOnPUCCH)' and 'PUSCH-based semi-persistent (semi-PersistentOnPUSCH)'. In the case of a periodic or semi-permanent CSI reporting method, the terminal may receive a PUCCH or PUSCH resource to transmit the CSI from the base station via upper layer signaling. The period and slot offset of the PUCCH or PUSCH resource to transmit the CSI may be given as the numerology of the uplink (UL) bandwidth portion configured for transmitting the CSI report. In the case of a non-periodic CSI reporting method, the terminal may receive a PUSCH resource to transmit the CSI scheduled from the base station via L1 signaling (the aforementioned DCI format 0_1).

[0332] For the aforementioned CSI resource setting (CSI-ResourceConfig), each CSI resource setting CSI-ReportConfig may include S (≥1) CSI resource sets (given by the upper-level parameter csi-RS-ResourceSetList). The CSI resource set list may consist of non-zero power (NZP) CSI-RS resource sets and SS / PBCH block sets, or may consist of CSI-interference measurement (CSI-IM) resource sets. Each CSI resource setting may be located in a downlink (DL) bandwidth portion identified by the upper-level parameter bwp-id, and the CSI resource setting may be linked to a CSI report setting in the same downlink bandwidth portion. The time domain operation of the CSI-RS resources within the CSI resource setting may be set to one of 'non-periodic', 'periodic', or 'semi-permanent' by the upper-level parameter resourceType. For periodic or semi-permanent CSI resource settings, the number of CSI-RS resource sets may be limited to S=1, and the set period and slot offset may be given by the numerology of the downlink bandwidth portion identified by bwp-id. The terminal may receive one or more CSI resource settings for channel or interference measurement from the base station via upper layer signaling, and may include, for example, the following CSI resources.

[0333] - CSI-IM resources for interference measurement

[0334] - NZP CSI-RS resources for interference measurement

[0335] - NZP CSI-RS resources for channel measurement

[0336] For CSI-RS resource sets associated with a resource setting where the upper-level parameter resourceType is set to 'Aperiodic', 'Periodic', or 'Semi-permanent', the Trigger State for a CSI reporting setting where reportType is set to 'Aperiodic' and the resource setting for channel or interference measurements for one or more component cells (CC) can be set as the upper-level parameter CSI-AperiodicTriggerStateList.

[0337] Non-periodic CSI reporting of the terminal can be performed using PUSCH, periodic CSI reporting can be performed using PUCCH, and semi-permanent CSI reporting can be performed using PUSCH when triggered or activated by DCI, and using PUCCH after being activated by the MAC control element (MAC CE). As described above, CSI resource settings can also be configured as non-periodic, periodic, or semi-permanent. Combinations between CSI reporting settings and CSI resource settings can be supported based on Table 30 below.

[0338]

[0339] Non-periodic CSI reporting can be triggered by the "CSI request" field of the aforementioned DCI format 0_1, which corresponds to the scheduling DCI for PUSCH. The terminal can monitor PDCCH, obtain DCI format 0_1, and obtain scheduling information and CSI request indicators for PUSCH. The CSI request indicator is N TSIt can be set to bits (=0, 1, 2, 3, 4, 5, or 6) and can be determined by the upper layer signaling (reportTriggerSize). One of the trigger states among one or more non-periodic CSI report trigger states that can be set by the upper layer signaling (CSI-AperiodicTriggerStateList) can be triggered by the CSI request indicator.

[0340] - If all bits of the CSI request field are 0, this may mean that a CSI report is not requested.

[0341] - If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is greater than 2NTs-1, then M CSI trigger states can be mapped to 2NTs-1 according to the selected mapping relationship, and one of the trigger states of 2NTs-1 can be indicated as a CSI request field.

[0342] - If the number of CSI trigger states (M) in the configured CSI-AperiodicTriggerStateLite is less than or equal to 2NTs-1, one of the M CSI trigger states may be indicated as a CSI request field.

[0343] Table 31 below may show an example of the relationship between a CSI request indicator and a CSI trigger state that can be indicated by that indicator.

[0344]

[0345] For a CSI resource within a CSI trigger state triggered by a CSI request field, the terminal can perform a measurement and generate a CSI therefrom (including at least one of the aforementioned CQI, PMI, CRI, SSBRI, LI, RI, or L1-RSRP, etc.). The terminal can transmit the acquired CSI using a PUSCH scheduled by the corresponding DCI format 0_1. When the 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "1", the terminal can multiplex the uplink data (UL-SCH) and the acquired CSI and transmit them to the PUSCH resource scheduled by DCI format 0_1. When the 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "0", the terminal can transmit by mapping only the CSI without the uplink data (UL-SCH) to the PUSCH resource scheduled by DCI format 0_1.

[0346] FIGS. 11 and 12 illustrate non-periodic CSI reporting methods when the CSI-RS offset is 0 according to an embodiment of the present disclosure.

[0347] Referring to FIG. 11, the terminal can monitor PDCCH (1101) to obtain DCI format 0_1, from which it can obtain scheduling information and CSI request information for PUSCH (1105). The terminal can obtain resource information for CSI-RS (1102) to be measured from the received CSI request indicator. The terminal can determine at what point in time to perform a measurement on the CSI-RS (1102) resource being transmitted based on the time when the DCI format 0_1 ​​is received and the parameter for the offset within the CSI resource set setting (e.g., the aperiodicTriggeringOffset described above) within the NZP CSI-RS resource set setting (NZP-CSI-RS-ResourceSet). More specifically, the terminal may receive the offset value X of the parameter aperiodicTriggeringOffset within the NZP-CSI-RS resource set setting as an upper layer signaling from the base station, and the set offset value X may represent the offset between the slot in which the DCI triggering the aperiodic CSI report is received and the slot in which the CSI-RS resource is transmitted. For example, the aperiodicTriggeringOffset parameter value and the offset value X may have a mapping relationship as described in Table 32 below.

[0348]

[0349] Referring to FIG. 12, the aforementioned offset value may be set to X=0. In this case, the terminal may receive CSI-RS (1102) in a slot (corresponding to slot 0 in FIG. 11) that receives DCI format 0_1, which triggers a non-periodic CSI report, and may report the CSI information measured by the received CSI-RS to the base station via PUSCH (1105). The terminal may obtain scheduling information for PUSCH (1105) for CSI reporting (information corresponding to each field of the aforementioned DCI format 0_1) from DCI format 0_1. For example, the terminal may obtain information about the slot to transmit PUSCH (1105) from the aforementioned time domain resource allocation information for PUSCH (1105) in DCI format 0_1. In one example of FIG. 11, the terminal obtains a K2 value corresponding to the slot offset value for PDCCH-to-PUSCH as 3, and accordingly, at the time when PUSCH (1105) receives PDCCH (1101), it can be transmitted from slot 3 (1109), which is 3 slots away from slot 0 (1106).

[0350] In one example of FIG. 12, the terminal can monitor the PDCCH (1201) to obtain DCI format 0_1, from which it can obtain scheduling information and CSI request information for PUSCH (1205). The terminal can obtain resource information for the CSI-RS (1202) to be measured from the received CSI request indicator. In one example of FIG. 12, an example may be shown 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 the slot (corresponding to slot 0 (1206) in FIG. 13) that received the DCI format 0_1 ​​triggering a non-periodic CSI report, and can report the CSI information measured by the received CSI-RS to the base station via PUSCH (1205).

[0351] Next, the Bandwidth Part (BWP) settings in a 5G communication system can be explained in detail.

[0352] FIG. 13 illustrates the configuration of a bandwidth part in a 5G communication system according to one embodiment of the present disclosure.

[0353] Referring to FIG. 13, the terminal bandwidth (UE bandwidth) (1400) can be configured into two bandwidth parts, namely Bandwidth Part #1 (BWP#1) (1301) and Bandwidth Part #2 (BWP#2) (1302). The base station can configure one or more bandwidth parts for the terminal, and for each bandwidth part, the following information can be configured as shown in Table 33.

[0354]

[0355] The above information can be transmitted by the base station to the terminal via upper-layer signaling, for example, Radio Resource Control (RRC) signaling. Among one or more configured bandwidth parts, at least one bandwidth part may be activated. Whether a configured bandwidth part is activated can be transmitted quasi-statically from the base station to the terminal via RRC signaling or dynamically via Downlink Control Information (DCI).

[0356] Prior to the RRC (Radio Resource Control) connection, the terminal can receive the Initial Bandwidth Part (Initial BWP) for initial connection from the base station via the MIB (Master Information Block). More specifically, during the initial connection phase, the terminal can receive configuration information regarding the Control Resource Set (CORESET) and Search Space via the MIB, through which the Physical Downlink Control Channel (PDCCH) can be transmitted to receive the system information required for initial connection (Remaining System Information; which may correspond to RMSI or System Information Block 1; SIB1). The Control Resource Set and Search Space configured via the MIB can each be regarded as Identity (ID) 0. The base station can notify the terminal via the MIB of configuration information, such as frequency allocation information, time allocation information, and numerology, for Control Resource Set #0. In addition, the base station may notify the terminal via the MIB of configuration information regarding the monitoring period and occasion for control area #0, i.e., configuration information for search area #0. The terminal may regard the frequency area set as control area #0 obtained from the MIB as an initial bandwidth part for initial access. At this time, the identifier (ID) of the initial bandwidth part may be considered as 0.

[0357] The settings for the bandwidth part supported by the above 5G can be used for various purposes.

[0358] According to one embodiment, if the bandwidth supported by the terminal is smaller than the system bandwidth, this can be supported through the bandwidth part setting. For example, by setting the frequency location of the bandwidth part (setting information 2) to the terminal, the terminal can transmit and receive data at a specific frequency location within the system bandwidth.

[0359] For the purpose of supporting different numerologies, a base station may set multiple bandwidth parts for a terminal. For example, to support data transmission and reception using both a 15 kHz subcarrier interval and a 30 kHz subcarrier interval for a terminal, two bandwidth parts may be set to subcarrier intervals of 15 kHz and 30 kHz, respectively. Different bandwidth parts may be frequency division multiplexed, and when data transmission and reception is to be performed with a specific subcarrier interval, the bandwidth part set to that subcarrier interval may be activated.

[0360] In addition, for the purpose of reducing the power consumption of the terminal, the base station may set bandwidth parts with different bandwidth sizes for the terminal. For example, if the terminal supports a very large bandwidth, such as 100 MHz, and always transmits and receives data using that bandwidth, very large power consumption may occur. In particular, in a situation where there is no traffic, monitoring unnecessary downlink control channels using a large bandwidth of 100 MHz can be very inefficient in terms of power consumption. To reduce the power consumption of the terminal, the base station may set a bandwidth part with a relatively small bandwidth, such as 20 MHz, for the terminal. In a situation where there is no traffic, the terminal can perform monitoring operations in the 20 MHz bandwidth part, and when data is generated, it can transmit and receive data using the 100 MHz bandwidth part according to the instructions of the base station.

[0361] In the method for configuring the above bandwidth part, terminals prior to RRC connection (Connected) can receive configuration information for the Initial Bandwidth Part through the Master Information Block (MIB) during the initial connection phase. More specifically, the terminal can receive a Control Resource Set (CORESET) for a downlink control channel through which Downlink Control Information (DCI) scheduling System Information Blocks (SIB) can be transmitted from the MIB of the Physical Broadcast Channel (PBCH). The bandwidth of the control resource set by the MIB can be considered as the Initial Bandwidth Part, and through the configured Initial Bandwidth Part, the terminal can receive the Physical Downlink Shared Channel (PDSCH) through which SIBs are transmitted. In addition to receiving SIBs, the Initial Bandwidth Part may also be utilized for Other System Information (OSI), paging, and Random Access.

[0362] When one or more bandwidth parts are set for a terminal, the base station may instruct the terminal to change the bandwidth part using the Bandwidth Part Indicator field within the DCI. For example, referring to FIG. 3, if the currently active bandwidth part of the terminal is Bandwidth Part #1 (301), the base station may instruct the terminal to Bandwidth Part #2 (302) using the Bandwidth Part Indicator within the DCI, and the terminal may perform a bandwidth part change to Bandwidth Part #2 (302) indicated by the received Bandwidth Part Indicator within the DCI.

[0363] As mentioned above, since DCI-based bandwidth part changes can be directed by a DCI that schedules a PDSCH or PUSCH (Physical Uplink Shared Channel), when a terminal receives a request to change a bandwidth part, it must be able to receive or transmit the PDSCH or PUSCH scheduled by the corresponding DCI without difficulty in the changed bandwidth part. To this end, the standard specifies requirements for the delay time (TBWP) required when changing a bandwidth part, which can be defined, for example, as shown in Table 34 below.

[0364]

[0365] The requirements for bandwidth part change delay time may support Type 1 or Type 2 depending on the terminal's capability. The terminal may report the supported bandwidth part delay time type to the base station.

[0366] In accordance with the requirements for the aforementioned bandwidth part change delay time, when a terminal receives a DCI containing a bandwidth part change indicator in slot n, the terminal can complete the change to the new bandwidth part indicated by the bandwidth part change indicator at a time not later than slot n + TBWP, and can perform transmission and reception for the data channel scheduled by the corresponding DCI in the changed new bandwidth part. When the base station intends to schedule a data channel to the new bandwidth part, it may determine the time domain resource allocation for the data channel by considering the terminal's bandwidth part change delay time (TBWP). That is, when the base station schedules a data channel to the new bandwidth part, in the method of determining the time domain resource allocation for the data channel, it may schedule the data channel after the bandwidth part change delay time. Accordingly, the terminal may not expect the DCI indicating the bandwidth part change to indicate a slot offset (K0 or K2) value smaller than the bandwidth part change delay time (TBWP).

[0367] If a terminal receives a DCI (e.g., DCI format 1_1 or 0_1) instructing a change in the bandwidth part, the terminal may not perform any transmission or reception during a time interval corresponding to the time interval from the third symbol of the slot in which the PDCCH containing the said DCI was received to the beginning of the slot indicated by the slot offset value (K0 or K2) indicated by the time domain resource allocation indicator field within the said DCI. For example, if a terminal receives a DCI instructing a change in the bandwidth part in slot n, and the slot offset value indicated by the said DCI is K, the terminal may not perform any transmission or reception from the third symbol of slot n to the symbol before slot n+K (i.e., the last symbol of slot n+K-1).

[0368] Next, we can explain how to set transmission and reception related parameters for each bandwidth part in 5G.

[0369] A terminal may receive one or more bandwidth parts from a base station, and may additionally receive parameters to be used for transmission and reception (e.g., uplink and downlink data channel and control channel related setting information, etc.) for each configured bandwidth part. For example, referring to FIG. 13, when a terminal receives bandwidth part #1 (1301) and bandwidth part #2 (1302), the terminal may receive transmission / reception parameter #1 for bandwidth part #1 (1301) and transmission / reception parameter #2 for bandwidth part #2 (1302). When bandwidth part #1 (1301) is activated, the terminal can perform transmission and reception with the base station based on transmission / reception parameter #1, and when bandwidth part #2 (1302) is activated, the terminal can perform transmission and reception with the base station based on transmission / reception parameter #2.

[0370] More specifically, the following parameters can be set from the base station to the terminal.

[0371] First, regarding the uplink bandwidth part, the information in Table 35 can be set.

[0372]

[0373]

[0374] According to [Table 35], the terminal may receive cell-specific (or cell-common or common) transmission-related parameters from the base station (e.g., parameters related to Random Access Channel (RACH), Physical Uplink Control Channel (PUCCH), and Physical Uplink Shared Channel) (corresponding to BWP-UplinkCommon). Additionally, the terminal may receive terminal-specific (or dedicated) transmission-related parameters from the base station (e.g., parameters related to PUCCH, PUSCH, Configured Grant PUSCH, and Sounding Reference Signal (SRS)) (corresponding to BWP-UplinkDedicated).

[0375] Next, regarding the downlink bandwidth part, the following information can be set as shown in Table 36.

[0376]

[0377]

[0378] According to [Table 36], the terminal may receive cell-specific (or cell-common or common) reception-related parameters from the base station (e.g., parameters related to the Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel) (corresponding to BWP-DownlinkCommon). Additionally, the terminal may receive terminal-specific (or dedicated) reception-related parameters from the base station (e.g., parameters related to PDCCH, PDSCH, Semi-persistent Scheduled PDSCH, and Radio Link Monitoring (RLM)) (corresponding to BWP-UplinkDedicated).

[0379] Below, the DRX (Discontinuous Reception) settings in a 5G communication system can be explained in detail.

[0380] FIG. 14 illustrates Discontinuous Reception (DRX) in a 5G communication system according to one embodiment of the present disclosure.

[0381] DRX may be an operation in which a terminal using the service receives data discontinuously while in an RRC connected state where a wireless link is established between the base station and the terminal. When DRX is applied, the terminal can turn on the receiver at specific points to monitor the control channel, and turn off the receiver if no data is received for a certain period to reduce the terminal's power consumption. The DRX operation may be controlled by a MAC layer device based on various parameters and timers.

[0382] Referring to FIG. 14, Active time (1405) may be the time during which the terminal wakes up at each DRX cycle to monitor the PDCCH. Active time (1405) may be defined as follows.

[0383] - drx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDL or drx-RetransmissionTimerUL or ra-ContentionResolutionTimer is running; or

[0384] - a Scheduling Request is sent on PUCCH and is pending; or

[0385] - 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

[0386] drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, ra-ContentionResolutionTimer, etc. are timers whose values ​​are set by the base station, and have the function of setting the terminal to monitor PDCCH when certain conditions are satisfied.

[0387] drx-onDurationTimer (1415) may be a parameter for setting the minimum time the terminal stays awake in a DRX cycle. drx-InactivityTimer (1420) may be a parameter for setting the additional time the terminal stays awake when receiving a PDCCH (1430) instructing a new uplink transmission or downlink transmission. drx-RetransmissionTimerDL may be a parameter for setting the maximum time the terminal stays awake to receive a downlink retransmission in a downlink HARQ procedure. drx-RetransmissionTimerUL may be a parameter for setting the maximum time the terminal stays awake to receive an uplink retransmission grant in an uplink HARQ procedure. drx-onDurationTimer, drx-InactivityTimer, drx-RetransmissionTimerDL, and drx-RetransmissionTimerUL may be set as, for example, time, number of subframes, number of slots, etc. ra-ContentionResolutionTimer can be a parameter for monitoring PDCCH in a random access procedure.

[0388] The inActive time (1410) is a time during which the PDCCH is not monitored or / or the PDCCH is not received during the DRX operation, and the remaining time after subtracting the Active time (1405) from the total time of performing the DRX operation may be the inActive time (1410). If the terminal does not monitor the PDCCH during the Active time (1405), it may enter a sleep or inActive state to reduce power consumption.

[0389] The DRX cycle can refer to the period during which a terminal wakes up and monitors the PDCCH. In other words, it can refer to the time interval or on-duration occurrence cycle between when the terminal monitors a PDCCH and when it monitors the next PDCCH. There can be two types of DRX cycles: short DRX cycle and long DRX cycle. The short DRX cycle can be applied optionally.

[0390] Long DRX cycle (1425) may be the longer of the two DRX cycles set in the terminal. While operating with Long DRX, the terminal may restart drx-onDurationTimer (1415) at a point where Long DRX cycle (1425) has elapsed from the starting point (e.g., start symbol) of drx-onDurationTimer (1415). When operating with Long DRX cycle (1425), the terminal may start drx-onDurationTimer (1415) in a slot after drx-SlotOffset in a subframe satisfying [Equation 2] below. Here, drx-SlotOffset may represent a delay before starting drx-onDurationTimer (1415). drx-SlotOffset may be set to, for example, time, the number of slots, etc.

[0391]

[0392] At this time, drx-LongCycleStartOffset may include Long DRX cycle (1525) and drx-StartOffset, and may be used to define the subframe to start Long DRX cycle (1425). For example, drx-LongCycleStartOffset may be set to time, number of subframes, number of slots, etc.

[0393] A short DRX cycle may be the shorter of the two DRX cycles defined in the terminal. The terminal may operate in a long DRX cycle (1425), and when a specific event occurs during the active time (1405), such as receiving a PDCCH (1430) instructing a new uplink transmission or downlink transmission, it may start or restart the drx-InactivityTimer (1420), and if the drx-InactivityTimer (1420) expires or a DRX command MAC CE is received, it may operate in a short DRX cycle. For example, in FIG. 14, the terminal may start the drx-ShortCycleTimer at the time of the previous drx-onDurationTimer (1415) or drx-InactivityTimer (1420) expiration, and operate in a short DRX cycle until the drx-ShortCycleTimer expires. When the terminal receives a PDCCH (1430) instructing a new uplink transmission or downlink transmission, it may extend the Active Time (1405) or delay the arrival of the InActive Time (1410) in anticipation of additional uplink transmission or downlink transmission in the future. While the terminal is operating in short DRX, it may start the drx-onDurationTimer (1415) again at a time when a short DRX cycle has elapsed from the start of the previous On duration. After that, when the drx-ShortCycleTimer expires, the terminal may operate in Long DRX cycle (1425) again.

[0394] When operating in a short DRX cycle, the terminal may start drx-onDurationTimer (1415) after drx-SlotOffset in a subframe satisfying [Equation 3] below. Here, drx-SlotOffset may represent a delay before starting drx-onDurationTimer (1415). For example, drx-SlotOffset may be set to time, the number of slots, etc.

[0395]

[0396] Here, drx-ShortCycle and drx-StartOffset can be used to define the subframe to start the Short DRX cycle. drx-ShortCycle and drx-StartOffset can be set, for example, to time, number of subframes, number of slots, etc.

[0397] Up to this point, the DRX operation can be explained with reference to FIG. 14. According to one embodiment, the terminal can reduce the power consumption of the terminal by performing the DRX operation. However, even if the terminal performs the DRX operation, the terminal may not always receive a PDCCH related to the terminal during Active Time (1405). Therefore, in one embodiment of the present disclosure, a signal controlling the operation of the terminal can be provided to save the power of the terminal more efficiently.

[0398] In 5G systems, a new terminal state called RRC_INACTIVE has been defined to reduce the energy and time consumed for the initial access of terminals. In addition to the operations performed by RRC_IDLE terminals, RRC_INACTIVE terminals can perform the following processes.

[0399] - Stores AS (Access stratum) information required for cell access

[0400] - Terminal-specific DRX cycle operation set by the RRC layer

[0401] - Configure RNA (RAN (radio access network)-based notification area) that can be utilized during handover by the RRC layer and perform periodic updates.

[0402] - Monitoring RAN-based paging messages transmitted via I-RNTI (inactive-radio network temporary identifier)

[0403] A terminal in the RRC_CONNECTED state can change from the RRC_CONNECTED state to the RRC_INACTIVE or RRC_IDLE state upon receiving an RRC Release instruction from the base station.

[0404] A terminal in the RRC_INACITVE or RRC_IDLE state can change from the RRC_INACTIVE or RRC_IDLE state to the RRC_CONNECTED state by performing random access and completing all random access procedures.

[0405] A scheduling method in which a base station transmits downlink data to a terminal or instructs the terminal to transmit uplink data may be described below.

[0406] Downlink Control Information (DCI) may be control information transmitted by a base station to a terminal via the downlink. Downlink Control Information may include downlink data scheduling information or uplink data scheduling information for a specific terminal. Generally, the base station may perform channel coding for the DCI independently for each terminal and then transmit it to each terminal via the Physical Downlink Control Channel (PDCCH), which is a downlink physical control channel.

[0407] A base station may operate by applying a predetermined DCI format to a terminal to be scheduled, depending on the purpose, such as whether it is scheduling information for downlink data (downlink assignment), scheduling information for uplink data (uplink grant), or DCI for power control.

[0408] The base station can transmit downlink data to the terminal via the Physical Downlink Shared Channel (PDSCH), which is a physical channel for transmitting downlink data. The base station can provide the terminal with scheduling information, such as specific mapping locations in the time and frequency domains of the PDSCH, modulation schemes, HARQ-related control information, and power control information, through the DCIs related to downlink data scheduling information among the DCIs transmitted via the PDSCH.

[0409] The terminal can transmit uplink data to the base station via the PUSCH (Physical Uplink Shared Channel), which is a physical channel for uplink data transmission. The base station can provide the terminal with scheduling information, such as specific mapping locations in the time and frequency domains of the PUSCH, modulation schemes, HARQ-related control information, and power control information, through the DCI related to uplink data scheduling information among the DCIs transmitted via the PDCCH.

[0410] For the RRC_IDLE / RRC_INACTIVE terminal, the aforementioned DRX operation is performed, and a paging message can be received. The terminal can monitor one Paging Occasion (PO) during the DRX cycle. The PO may be a set of PDCCH monitoring occasions and may include multiple time slots (or subframes, or OFDM symbols) in which paging control information can be transmitted and received. The Paging Frame (PF) may be a single radio frame (10ms) and may include one or more POs or the start point of the PO (e.g., an offset).

[0411] PF and PO can be determined by the following formulas.

[0412] The System Frame Number (SFN) for the PF can be determined by (SFN + PF_offset) mod T = (T div N) * (UE_ID mod N), where PF_offset is an offset for determining the PF, T is a DRX cycle, and N is the number of PFs per DRX cycle (e.g., cell common, cell specific), which can be determined by a higher signal such as system information, and UE_ID is a terminal ID (e.g., 5G-S-TMSI), which can be determined by the core network.

[0413] The PFs determined by N may refer to paging frames that are commonly applied to terminals within a cell, and may be referred to as cell common PFs for convenience.

[0414] i_s, which indicates the PO index, can be determined by i_s = floor (UE_ID / N) mod Ns, where Ns can represent the number of POs in a single PF and can be determined by higher signals such as system information.

[0415] For example, assuming PF_offset=3, T=128, N=T / 4=32, Ns=4, UE_ID mod 32 is 1, and floor(UE_ID / 32) mod 4 is 1, the parameter values ​​can be determined by the following formula.

[0416] (SFN + 3) mod 128 = (128 div 32)*(UE_ID mod 32) = 4*1 = 4,

[0417] i_s = floor (UE_ID / 32) mod 4 = 1

[0418] Therefore, the paging frame PF that a terminal with the above UE_ID must receive can be determined as a radio frame with SFN 1, 129, 257, ... among the cell common PFs, and the PO can be determined as the (i_s + 1)th PO among the 4 POs within the PF.

[0419] The reception of PEI (Paging Early Indication) can be described in more detail below. In order to reduce terminal power consumption while monitoring and receiving the paging control channel and paging data channel in every DRX cycle, the terminal may receive PEI.

[0420] According to various embodiments of the present disclosure, a terminal may monitor or receive a PEI Occasion (PEI-O) once before receiving paging during a DRX cycle. When the terminal receives a PEI and the PEI indicates a subgroup and paging occasion to which the terminal belongs, the terminal belonging to the subgroup may monitor the associated paging occasion (PO). If the terminal does not detect the PEI in the PEI occasion, or if the PEI does not indicate a subgroup and paging occasion to which the terminal belongs, the terminal does not need to monitor the associated paging occasion (PO), thereby reducing terminal power consumption.

[0421] The terminal can determine the PEI occlusion as follows. The PEI occlusion may be located backward by a subframe offset relative to the radio frame of a reference point that is located forward by pei-FrameOffset relative to the PF containing the associated PO. The terminal can monitor the PEI at the PEI occlusion determined by the above method. Here, pei-FrameOffset, subframe offset, etc., may be determined by higher-level signals such as system information.

[0422] Embodiments of the present disclosure may be described in detail below with reference to the accompanying drawings. The contents of the present disclosure may be applicable to FDD, TDD and / or XDD (and / or SBFD, full duplex) systems. In the present disclosure below, upper signaling (or upper layer signaling) is a signal transmission method transmitted from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel, and may be referred to as RRC signaling, PDCP signaling, or MAC (medium access control) control element (MAC control element; MAC CE).

[0423] For convenience in the following description of the present disclosure, cells, transmission points, panels, beams, and / or transmission directions that can be distinguished through upper layer / L1 parameters such as TCI state or spatial relation information, or indicators such as cell ID, TRP ID, and panel ID, may be described uniformly as TRP (transmission reception point), beam, or TCI state. Accordingly, when applying the present disclosure in practice, TRP, beam, or TCI state may be appropriately replaced with one of the above terms.

[0424] Embodiments of the present disclosure may be described in detail below with reference to the accompanying drawings. Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, Node B, BS (Base Station), wireless access unit, base station controller, or a node on a network. A terminal may include a UE (User Equipment), MS (Mobile Station), cellular phone, smartphone, computer, or a multimedia system capable of performing communication functions. Although embodiments of the present disclosure are described below using a 5G system as an example, embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types. For example, LTE or LTE-A mobile communication and mobile communication technologies developed after 5G may be included therein. Accordingly, embodiments of the present disclosure may be applied to other communication systems with some modifications without significantly departing from the scope of the present disclosure, as judged by a person skilled in the art. The contents of the present disclosure may be applicable to FDD, TDD, XDD (or SBFD, full duplex) systems.

[0425] Furthermore, in describing the present disclosure, if it is determined that a detailed description of related functions or configurations could unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined in consideration of their functions within the present disclosure, and these definitions may vary depending on the intent or practices of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0426] In describing the present disclosure below, the term "upper layer signaling" may refer to a signaling corresponding to at least one or a combination of at least one of the following signalings.

[0427] - MIB (Master Information Block)

[0428] - SIB (System Information Block) or SIB

[0429] - RRC (Radio Resource Control)

[0430] - MAC (Medium Access Control) CE (Control Element)

[0431] In addition, L1 signaling may be a signaling corresponding to at least one or a combination of at least one of the following physical layer channels or signaling methods using signaling.

[0432] - PDCCH (Physical Downlink Control Channel)

[0433] - DCI (Downlink Control Information)

[0434] - Terminal-specific (UE-specific) DCI

[0435] - Group common DCI

[0436] - Common DCI

[0437] - Scheduling DCI (e.g., DCI used for the purpose of scheduling downlink or uplink data)

[0438] - Non-scheduling DCI (e.g., DCI not intended for scheduling downlink or uplink data)

[0439] - PUCCH (Physical Uplink Control Channel)

[0440] - UCI (Uplink Control Information)

[0441] The term "slot" used in the present disclosure below is a general term that may refer to a specific time unit corresponding to TTI (Transmit Time Interval), and specifically, it may refer to a slot used in a 5G NR system, or a slot or subframe used in a 4G LTE system.

[0442] The present disclosure may be applied to RRC idle, RRC inactive, and RRC connected terminals.

[0443] In the present disclosure, the statement that a particular cell is for data communication and / or data communication only may include the particular cell performing not only data communication but also other signal transmission and reception. For example, signal transmission and reception other than sinking and / or connecting may be included in the data communication.

[0444] The following embodiments may relate to a method and apparatus for reducing the delay time for CA. In particular, when CA is absolutely necessary, the delay time from RA to SCell activation in conventional operations can be very large. Such delay time can cause a reduction in terminal throughput and inefficient resource utilization.

[0445] The first and second embodiments described below may be carried out separately and / or at least some of them may be carried out in combination.

[0446] <1st Embodiment>

[0447] The first embodiment may relate to the operation of a cellular system utilizing a spectrum when various spectra are present.

[0448] Spectra with various frequency bands exist, and with the emergence of new generations of cellular systems, the spectrum used by previous generations of cellular systems may be replaced by the spectrum for the immediate or new generation of cellular systems. For example, with the advent of 6G systems, services for 3G or 4G are gradually reduced, and their spectrum may be repurposed for 5G or 6G use to increase the speed of 5G or 6G. Compared to 5G, 3G or 4G systems operate using multiple narrow bandwidths. Since these narrow bandwidths may not be suitable for data transmission and reception, they may be used for limited purposes. For example, they can be divided into an access layer responsible for access functions for idle UEs and a capacity layer responsible for data transmission and reception for connected UEs. For convenience, they may be referred to as A and C respectively. A may be referred to as the first cell. C may be referred to as the second cell.

[0449] Operators operating cellular communications possess various spectra, which can be broadly classified into refarming spectra, spectra reused from current 4G or 5G, and spectra dedicated for next-generation communications. These spectra allow for the coexistence of A and C in various combinations. For example, when operating a combination of two or more spectra, A and C can be operated separately, whereas there may also be cases where A and C are used within a single spectra, as is done conventionally. However, to operate several narrow bands and one or two wide bands, as in the former case, it may be effective to utilize Carrier Aggregation (CA) to operate A as a narrow band and C as a wide band.

[0450] The existing CA environment may be limited to terminals in connected mode. Therefore, a connected terminal must first connect to a serving cell, additionally receive RRC configuration, receive a SCell activation message, and finally undergo measurement and CSI reporting for the SCell before SCell activation can be completed.

[0451] Figure 15 is a diagram showing the timeline from random access to SCell activity in the existing CA operation.

[0452] Referring to FIG. 15, in the existing operation, the idle terminal performs random access to A (1501) and becomes RRC connected (1503). At this time, if the network determines that the terminal requires CA, it may start a procedure to add SCell for CA. A becomes a PCell, and can receive RRC configurations, etc., required for adding SCell for CA from this PCell. At this time, since the RRC message is transmitted via PDSCH, the terminal may send a HARQ ACK / NACK to indicate whether the PDSCH has been received successfully. Upon successful receipt of the ACK, the network may issue a SCell activation command (1504) to MAC-CE. Therefore, the delay time (1511) between (1503) and (1504) may be extended depending on the time the network issues a trigger for SCell activation to the terminal after receiving and responding to the SCell-related RRC message. Upon receiving (1504), the terminal sends back a HARQ ACK / NACK in response to the MAC-CE, and can then perform a measurement of the SCell using the SSB or TRS that comes down. Then, the SCell activation can be completed (1505) by receiving the CSI-RS and making a CSI report. A detailed explanation of the delay time between (1504) and (1505) can be described in FIGS. 16 and FIGS. 17. After (1505), the terminal is fully connected to C, and from (1506), data transmission and reception from C may be possible.

[0453] Figure 16 is a diagram showing the detailed timeline from the terminal receiving the SCell activation command in the existing CA to SCell activation.

[0454] According to FIG. 16, the base station may transmit a CA-related SCell activation command (1601) to the terminal. (1601) contains an instruction indicating a specific SCell among the SCell list existing in the CA-related RRC configuration received during (1511), and can be transmitted to MAC-CE in the nth slot. Upon receiving MAC-CE, the terminal must transmit a HARQ ACK / NACK to the corresponding PCell, which is T HARQ This can be done within (1611). After the HARQ is transmitted in the n+m-th slot of (1602), the terminal can perform RF warmup and switching to receive the synchronization signal from the carrier of the SCell and the MAC-CE process. Subsequently, a synchronization signal (e.g., SSB) can be transmitted from the SCell, and the terminal can perform ACG gain settling, cell search, time-frequency tracking, etc. This process can be done within (1611). activation_time (1612) can be completed. Afterwards, the terminal obtains the first available DL CSI-RS from SCell, and T sends the CSI reporting to SCell, taking into account the processing time for the CSI reporting based on the CSI-RS. CSI_reporting Transmit within (1613) and the final SCell activation can be completed.

[0455] Figure 17 is a diagram showing the timeline for fast SCell activation.

[0456] Fast SCell activation may be a procedure for activating SCell faster than the SCell activation in Fig. 16. Unlike Fig. 16, which requires receiving several SSBs transmitted over long periods, this allows for rapid synchronization using short-period TRS bursts. Therefore, most of the procedure for SCell activation is similar to Fig. 16, with only differences in the type of synchronization signal.

[0457] Referring to FIG. 17, the UE is configured with a non-periodic CSI-RS resource for tracking SCells for fast SCell activation using NZP-CSI-RS-ResourceSet(s) having the upper layer parameter scellActivationRS-ConfigToAddModList, and the QCL relationship can be provided by the upper layer parameter qcl-Info.

[0458] PCell can transmit an Enhanced Scell ​​Activation / Deactivation MAC-CE in the nth slot (1701) that triggers one or two CSI-RS bursts for fast SCell activation for the disabled SCell(s).

[0459] When the terminal receives this,

[0460] - If MAC-CE indicates that the first CSI-RS burst for SCell activation exists in SCell, the UE can assume that the first CSI-RS burst for SCell activation exists in that SCell. The first slot of the first CSI-RS burst can start in the m1SCell slot (1711) after the last SCell slot that corresponds to the reference slot n+k.

[0461] - If MAC-CE indicates that a second CSI-RS burst for SCell activation exists in SCell, the UE may assume that a second CSI-RS burst for SCell activation exists in that SCell. The first slot of the second CSI-RS burst may start in the m2SCell slot (1721) after the end of the first CSI-RS burst. The CSI-RS of the second burst may have the same antenna port index, OFDM symbol assignment within the slot, and the same PRB assignment location as the CSI-RS of the first burst.

[0462] - A CSI-RS burst is defined as 4 CSI-RS resources in 2 consecutive slots, and m1 and m2 can be provided by aperiodicTriggeringOffsetL2 of NZP-CSI-RS-ResourceSet and gapBetweenBursts associated with CSI-RS burst(s) triggered by MAC-CE, respectively.

[0463] Figure 18a is a diagram showing the two octet structures of a trigger for MAC CE-based fast SCell activation.

[0464] Figure 18b is a diagram showing the two octet structures of a trigger for MAC CE-based fast SCell activation.

[0465] Referring to FIGS. 18a and 18b, an Enhanced SCell Activation / Deactivation MAC CE having a single octet Ci field can be identified by a MAC subheader having an eLCID. The size is variable, and the C to be activated i 7 C-fields, 1 R-field, and TRS ID based on ScellIndex for SCell indicated by field(s). jIt can be composed of zero or more fields in ascending order. One octet C i An Enhanced SCell Activation / Deactivation MAC CE having a field can be defined as shown in FIG. 19(a).

[0466] 4 octet C i The Enhanced SCell Activation / Deactivation MAC CE having a field can be identified by a MAC subheader having a specified eLCID. The size is variable, and the 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 can be organized in ascending order by field. 4 octet C i An Enhanced SCell Activation / Deactivation MAC CE having a field can be defined as shown in FIG. 19(b).

[0467] The definitions for each field can be specifically as follows.

[0468] - C i : If there is a SCell configured in the MAC entity, this field indicates the enabled / disabled status of the SCell as SCellIndex i; otherwise, the MAC entity is C i You can ignore the field. C i The field requires that the SCell with SCellIndex i be enabled, and the TRS ID for the SCell j It can be 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 that the TRS ID field for this SCell is not included.

[0469] - TRS ID j: TRS ID j If set to a non-zero value, it may indicate that the corresponding TRS is enabled by scellActivationRSId. TRS ID j If set to 0, it indicates that TRS is not used for the corresponding SCell.

[0470] - R: Reserved bit, set to 0.

[0471] Therefore, in FIG. 15, a long latency (1513) is required for the latency from (1503) to (1505), and in an environment where CA operation is expected for most terminals, reducing this latency can lead to an increase in throughput due to the fast data transmission and reception of the terminals.

[0472] Since the narrow bandwidths used in 3G and 4G have lower carrier frequencies than the wide frequencies used or to be used in 5G or 6G, in most cases, a narrow bandwidth with a low carrier frequency is used for the purpose of A, while a wide bandwidth with a relatively high carrier frequency is used for the purpose of C. Therefore, when many idle UEs monitor A and data transmission / reception is required, C can be additionally utilized to perform CA operations. In this case, under the existing operation, all terminals may assign PCell to A and SCell to C, which can place a burden on A, which has a narrow bandwidth. To reduce this burden on A, a method of setting C to PCell during the CA phase can be considered.

[0473] <2nd Example>

[0474] The second embodiment may relate to a procedure in which an idle terminal performs CA quickly and selects a PCell / SCell in a structure according to the first embodiment.

[0475] Figure 19 is a diagram of CA without delay time.

[0476] Referring to FIG. 19, it can be seen that the terminal obtains synchronization for both A (1901) and C (1902) before RA, and SCell activation is completed (1903) simultaneously with the completion of RA.

[0477] In other words, conventional CA as shown in Fig. 15 can only perform the CA procedure after the terminal is always in a connected state, and since measurement for SCell must be performed particularly after RA, this can be a major obstacle in terms of latency. On the other hand, in a multi-layer environment where CA is supported by default, as shown in Fig. 19, the procedure for CA is performed in the idle state of the terminal, which can significantly reduce the terminal's power consumption and latency.

[0478] For an operation such as that shown in Fig. 19, prior to RA, the terminal may instruct A to measure the C cells for CA. This is an operation that the existing terminal is already performing, but in the case of intra-frequency measurement, it may be performed only when the link performance with the serving cell (e.g., RSRP or RSRQ) is worse than a specific threshold. In the case of inter-frequency measurement, for cells with a higher priority for inter-frequency than the serving cell, the higher priority inter-frequency layer can be searched at least every Thigher_priority_search. Since the two types of cells, A and C, will have different frequency bands for CA, inter-frequency measurement for non-priority-based C cells capable of CA may be performed instead of the existing priority-based inter-frequency measurement. The terminal, having obtained measurement values ​​for C cells (e.g., RSRP and RSRQ) through inter-frequency measurement, can compare them using a separate / A threshold or A's RSRP and RSRQ values. If a separate / A threshold is used, the terminal can receive it from cell A. And if the measurement value for cell C exceeds the reference value, the terminal obtains synchronization for cell C as well as cell A (the terminal can achieve accurate synchronization by receiving multiple synchronization signals from cell C).

[0479] The advantages of such a latency-free CA compared to existing CAs may include the fact that separate responses to RRC configuration and SCell activation commands are not required, and separate reporting of measurements is not necessary.

[0480] During the RA process, the idle terminal can determine the PCell based on the measurement value. For example, if the measurement value of C is greater than the measurement value of A, the terminal can perform RA using the RACH occasion set in C. Of course, in this case, information regarding the preamble related to the RACH occasion for C may need to be provided by A using system information. In this case, C can be the PCell and A can be the SCell.

[0481] On the other hand, if the measured value of C exceeds the reference value but is greater than the measured value of A, the terminal can select A as PCell and C as SCell via CA. Alternatively, it can connect only to A without CA.

[0482] If C is deactivated and the terminal cannot measure it (i.e., unknown cell), the terminal may have difficulty activating the cell simultaneously with the completion of RA. In this case, the terminal can receive information about the C cell for CA during the RA process through A.

[0483] Figure 20 illustrates the procedure for receiving and measuring information about another cell for CA and establishing an RRC connection during the RA process.

[0484] Referring to FIG. 20, the terminal (2001) may transmit PRACH (S2011) to A if it has not found C (2003) or if it determines that it is reasonable for A (2002) to become the serving cell. Based on the transmitted PRACH, A may transmit RAR. Additionally, A may provide information about C to inform the terminal whether to set C as a PCell (S2012). This information may include C's cell ID or / and information on the synchronization signal (resource location, period, etc.), C's carrier frequency, etc. Based on the information provided by A, the terminal may receive a synchronization signal (S2013) transmitted from C. This synchronization signal may be an on-demand synchronization signal transmitted at the request of the A cell. Upon measuring the synchronization signal transmitted from C, the terminal may transmit to A a request for an RRC connection, along with information on whether CA is possible to C or whether attachment is possible. Whether C and CA are possible can be indicated by 1 bit, or if multiple C layer cells were provided in (S2012), a list of possible cells in the form of a bitmap can be provided. Additionally, the time between (S2012) and (S2014) may be longer than usual, taking into account (S2013). For example, the terminal may send (S2014) considering the processing time based on the time (S2013) ends. If the possibility of C and CA being possible in (S2014) is false, the terminal establishes an RRC connection with A as before. On the other hand, if it is true, A may provide additional system information about C to the terminal via (S2015). This information may include resource locations, preamble sets, subcarrier spacing, etc., for the RACH occasions set by C.Based on this, the terminal can send a request to establish an RRC connection to C by sending PRACH or Msg A, which sends Msg 1 and Msg 3 together. Finally, C can complete the CA procedure by sending RAR and RRC connection setup (which may be Msg B if sent together) to the terminal, thereby setting C as PCell and A as SCell.

[0485] In the above example, the terminal can describe a method of selecting C as the PCell to reduce the burden of A as the PCell, while maintaining the roles of PCell and SCell as before during the CA process.

[0486] On the other hand, A can be maintained as a PCell and C as a SCell, allowing for the dynamic separation of their roles and the sharing of the burden. For instance, there are several differences between PCells and SCells in existing operations; for instance, a PCell always remains active, whereas a SCell can alternate between active and inactive states according to instructions from the base station. Terminal mobility is controlled primarily by the PCell, while the SCell can be understood as an additional serving cell for data transmission and reception. Consequently, RRC configuration is provided only by the PCell, and scheduling DCI instructions for the SCell can also be provided only by the PCell. Based on the above operations, if C becomes the PCell, the following issues may arise. Since C's coverage is smaller than or equal to A's, maintaining terminal mobility within A might be a better choice. Conversely, if A becomes the PCell, the terminal may experience reduced flexibility regarding RRC configuration and DCI. Therefore, for mobility, PCell remains A, while the capabilities for RRC configuration and DCI transmission can be provided separately in PCell / SCell. This can offset the disadvantages of both.

[0487] FIG. 21 illustrates a terminal transceiver device according to one embodiment of the present disclosure. For convenience of explanation, devices not directly related to the present disclosure may be omitted from illustration and description.

[0488] Referring to FIG. 21, the terminal may include a transmitter (2104) comprising an uplink transmission processing block (2101), a multiplexer (2102), and a transmission RF block (2103), a receiver (2108) comprising a downlink reception processing block (2105), a demultiplexer (2106), and a reception RF block (2107), and a control unit (2109). The control unit (2109) can control each of the constituent blocks of the receiver (2108) for receiving a data channel or control channel transmitted by the base station as described above, and each of the constituent blocks of the transmitter (2104) for transmitting an uplink signal.

[0489] In the transmission unit (2104) of the terminal, the uplink transmission processing block (2101) 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 (2101) can be multiplexed with other uplink signals by a multiplexer (2102), then processed by a transmission RF block (2103), and then transmitted to a base station.

[0490] The terminal receiver (2108) can demultiplex a signal received from a base station and distribute it to each downlink reception processing block. The downlink reception processing block (2105) can obtain control information or data transmitted by the base station by performing processes such as demodulation and channel decoding on the downlink signal of the base station. The terminal receiver (2108) can apply the output result of the downlink reception processing block to the control unit (2109) to support the operation of the control unit (2109).

[0491] FIG. 22 is a block diagram of a terminal according to one embodiment of the present disclosure.

[0492] As illustrated in FIG. 22, the terminal of the present disclosure may include a processor (2230), a transceiver (2210), and a memory (2220). However, the components of the terminal are not limited to the examples described above. For example, the terminal may include more components or fewer components than those described above. Furthermore, the processor (2230), the transceiver (2210), and the memory (2220) may be implemented in the form of a single chip. According to one embodiment, the transceiver (2210) of FIG. 22 may include the transceiver (2104) and the receiver (2108) of FIG. 21. Additionally, the processor (2230) of FIG. 22 may include the control unit (2109) of FIG. 21.

[0493] According to one embodiment, the processor (2230) can control a series of processes that allow the terminal to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the components of the terminal can be controlled to perform a transmission and reception method of the terminal depending on whether the base station mode is a base station energy saving mode or a base station general mode. The processor (2230) may be one or a plurality of processors, and the processor (2230) can perform a transmission and reception operation of the terminal in a wireless communication system applying the carrier band of the present disclosure described above by executing a program stored in memory (2220).

[0494] The transceiver (2210) can transmit and receive signals with a base station. The signals transmitted and received with the base station may include control information and data. The transceiver (2210) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (2210), and the components of the transceiver (2210) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (2210) can receive a signal through a wireless channel and output it to a processor (2230), and transmit the signal output from the processor (2230) through a wireless channel.

[0495] According to one embodiment, the memory (2220) may store programs and data necessary for the operation of the terminal. Additionally, the memory (2220) may store control information or data included in signals transmitted and received by the terminal. The memory (2220) may be composed of a storage medium or a combination of storage media such as ROM, RAM, hard disk, CD-ROM, and DVD. Additionally, the memory (2220) may be a plurality of. According to one embodiment, the memory (2220) may store a program for performing the transmission and reception operation of the terminal depending on whether the base station mode, which is an embodiment of the present disclosure described above, is a base station energy saving mode or a base station general mode.

[0496] Additionally, the processor (2230) may control a series of processes to enable the base station to operate according to at least one of the embodiments of FIGS. 1 through 21. The processor (2230) may include at least one processor. Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0497] FIG. 23 is a block diagram of a base station according to one embodiment of the present disclosure.

[0498] As illustrated in FIG. 23, the base station of the present disclosure may include a processor (2330), a transceiver (2310), and a memory (2320). However, the components of the base station are not limited to the examples described above. For example, the base station may include more components or fewer components than the components described above. In addition, the processor (2330), the transceiver (2310), and the memory (2320) may be implemented in the form of a single chip.

[0499] The processor (2330) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. For example, according to the embodiments of the present disclosure, the components of the base station can be controlled to perform a method of scheduling a terminal depending on whether the base station mode is a base station energy saving mode or a base station general mode. The processor (2330) may be one or a plurality of processors, and the processor (2330) can perform the method of the present disclosure described above by executing a program stored in memory (2320).

[0500] The transceiver (2310) can transmit and receive signals with a terminal. The signals transmitted and received with the terminal may include control information and data. The transceiver (2310) may be composed of an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies a received signal and down-converts the frequency. However, this is merely one embodiment of the transceiver (2310), and the components of the transceiver (2310) are not limited to an RF transmitter and an RF receiver. Additionally, the transceiver (2310) can receive a signal through a wireless channel and output it to a processor (2330), and transmit the signal output from the processor (2330) through a wireless channel.

[0501] According to one embodiment, the memory (2320) may store programs and data necessary for the operation of the base station. Additionally, the memory (2320) may store control information or data included in signals transmitted and received by the base station. The memory (2320) may be composed of a storage medium or a combination of storage media such as ROM, RAM, a hard disk, a CD-ROM, and a DVD. Additionally, there may be multiple memories (2320). According to one embodiment, the memory (2320) may store a program for performing the methods of the embodiments of the present disclosure described above.

[0502] Additionally, the processor (2330) can control a series of processes to enable the base station to operate according to at least one of the embodiments of FIGS. 1 through 21. The processor (2330) may include at least one processor. Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present disclosure.

[0503] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disc storage device, compact disc-ROM (CD-ROM), digital versatile discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in a memory composed of some or all of these. Additionally, each constituent memory may include multiple units. The above program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, LAN (local area network), WAN (wide area network), or SAN (storage area network), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0504] In the specific embodiments of the present disclosure described above, the components included in the present disclosure are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0505] Meanwhile, the present specification and drawings disclose preferred embodiments of the present disclosure. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the disclosure, and are not intended to limit the scope of the present disclosure. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated together as needed.

[0506] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. A method of a UE (user equipment) transmitting and receiving signals in a wireless communication system, Step of synchronizing with the first cell; The step of receiving a first control signal from the first cell, the first cell including information about a controllable cell; and A step comprising transmitting data to a second cell based on the first control signal. UE's method.

2. In Paragraph 1, A step of obtaining a measurement value for the second cell through intra-frequency measurement or inter-frequency measurement; and A method of a UE comprising the step of comparing a measurement value for the second cell and a measurement value for the first cell.

3. In Paragraph 2, A method of a UE comprising the step of receiving data from the first cell when using a measurement value for the first cell.

4. In Paragraph 2, A method of a UE comprising the step of synchronizing with the second cell when the measurement value for the second cell exceeds a reference value.

5. In Paragraph 2, A method of a UE comprising the step of determining a PCell based on a measurement value for the second cell and a measurement value for the first cell.

6. A method of a UE (user equipment) transmitting and receiving signals in a wireless communication system, A step of transmitting PRACH (physical random access channel) to the first cell; A step of receiving a random access response (RAR) containing information about a second cell from the first cell; A step of receiving a synchronization signal from the second cell based on the above RAR; and A method of a UE comprising the step of transmitting an RRC (radio resource control) connection request message to the first cell.

7. In Paragraph 6, A method of a UE, wherein information regarding the second cell is information for performing switching to the second cell, and the information regarding the second cell includes at least one of the cell ID of the second cell, information of the synchronization signal, or the carrier frequency of the second cell.

8. In Paragraph 6, The step of transmitting PRACH to the first cell is, A step of determining whether it is reasonable for the first cell above to become a serving cell; and A method of a UE comprising the step of transmitting the PRACH to the first cell by determining that it is reasonable for the first cell to become a serving cell.

9. In Paragraph 6, A method of a UE in which the above RRC connection request message includes information indicating whether CA (carrier aggregation) is possible with the second cell or information indicating whether attachment to the second cell is possible.

10. In Paragraph 6, If the second cell and CA (carrier aggregation) or the second cell can be attached, the step of receiving system information about the second cell from the first cell; and A method of a UE comprising the step of performing an RRC connection with the first cell when the second cell and CA (carrier aggregation) or the second cell cannot be attached.

11. In a UE (user equipment) that transmits and receives signals in a wireless communication system, Transmitter / receiver; and It includes a control unit, and the control unit, Transmit PRACH (physical random access channel) to the first cell, and A random access response (RAR) containing information about the second cell is received from the first cell, and Receive a synchronization signal from the second cell based on the above RAR; and A UE configured to transmit an RRC (radio resource control) connection request message to the first cell.

12. In Paragraph 11, Information regarding the second cell is information for performing switching to the second cell, wherein the information regarding the second cell includes at least one of the cell ID of the second cell, information of the synchronization signal, or the carrier frequency of the second cell.

13. In Paragraph 11, The above control unit is, Determining whether it is reasonable for the above-mentioned first cell to become a serving cell; and A UE configured to transmit the PRACH to the first cell by determining that it is reasonable for the first cell to become a serving cell.

14. In Paragraph 11, The above RRC connection request message includes information indicating whether CA (carrier aggregation) is possible with the second cell or information indicating whether it is possible to attach to the second cell, in a UE.

15. In Paragraph 11, The above control unit is, If the second cell and CA (carrier aggregation) or attachment to the second cell is possible, system information regarding the second cell is received from the first cell; and A UE configured to perform an RRC connection with the first cell when CA (carrier aggregation) or attachment to the second cell is not possible.

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