Artificial intelligence-based CSI-RS compression method and device in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting higher data transmission rates. In addition, the present disclosure provides a method and device for compressing and transmitting a channel state information-reference signal (CSI-RS) for reducing channel state information-reference signal overhead of a base station in a mobile communication system. According to the present disclosure, it is possible to solve the problem of excessive waste of radio resources for channel state information reference signal transmission of a base station in a mobile communication system and achieve high data transmission rates.

Description

Artificial Intelligence-based CSI-RS compression method and device in wireless communication systems

[0001] The present disclosure relates to a wireless communication system, and more specifically, to an artificial intelligence-based CSI-RS (channel state information reference signal) compression method and apparatus in a wireless communication system.

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

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

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

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

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

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

[0008] The present disclosure provides a method and apparatus for reducing CSI-RS (channel state information-reference signal) overhead through CSI-RS compression using artificial intelligence (AI) 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] The present disclosure relates to a method performed by a terminal (user equipment, UE) in a wireless communication system, comprising: receiving a channel state information-reference signal (CSI-RS) and related information from a base station; measuring a compressed CSI-RS transmitted from the base station based on the channel state information-reference signal and related information; estimating a channel state for a compressed CSI-RS port through the measurement; restoring a channel for an entire CSI-RS port based on the channel for the compressed CSI-RS port; and feeding back channel state information of the restored entire CSI-RS port to the base station.

[0011] A method for a base station to compress and transmit / receive a channel state information reference signal to a terminal in a wireless communication system according to one embodiment of the present disclosure comprises: a step in which the base station transmits the compressed channel state reference signal and related information to the terminal through port transformation; and a method characterized by receiving and obtaining channel state information for the entire channel state information reference signal port from the terminal.

[0012] A method for transmitting and receiving a compressed channel state information reference signal in a wireless communication system according to one embodiment of the present disclosure comprises: the terminal receiving information related to the channel state information reference signal from a base station; measuring the compressed channel state information reference signal transmitted from the base station based on the information; estimating the channel state for a compressed channel state information reference signal port based on the measurement of the compressed channel state information reference signal; obtaining channel state information for an entire channel state information reference signal port based on the channel for the compressed channel state information reference signal port; and feeding back the channel state information for the entire channel state information reference signal port to the base station.

[0013] In addition, a method performed by a terminal of a wireless communication system comprises: receiving compression setting information related to a channel state information reference signal (CSI-RS) from a base station; receiving the CSI-RS corresponding to a compressed CSI-RS port from the base station based on the compression setting information related to the CSI-RS; obtaining a first channel state based on the received CSI-RS corresponding to the compressed CSI-RS port; obtaining a second channel state corresponding to all or part of the CSI-RS port based on the obtained channel state; and transmitting channel state information indicating the second channel state corresponding to all or part of the CSI-RS port to the base station, wherein the compressed CSI-RS port corresponds to a part of the entire CSI-RS port, and the compressed CSI-RS port is based on the entire CSI-RS port and a port switching matrix.

[0014] In addition, a method performed by a base station of a wireless communication system comprises: a step of transmitting compression setting information related to a channel state information reference signal (CSI-RS) to a terminal; a step of transmitting to the terminal a CSI-RS corresponding to a compressed CSI-RS port corresponding to the compression setting information related to the CSI-RS; and a step of receiving channel state information from the terminal indicating a second channel state corresponding to all or part of the CSI-RS ports, wherein the second channel state is derived from a first channel state corresponding to the compressed CSI-RS port, the compressed CSI-RS port corresponds to a part of the entire CSI-RS port, and the compressed CSI-RS port is based on the entire CSI-RS port and a port switching matrix.

[0015] Additionally, a terminal of a wireless communication system comprises: a transceiver; and a control unit configured to receive compression setting information related to a channel state information reference signal (CSI-RS) from a base station, receive the CSI-RS corresponding to a compressed CSI-RS port from the base station based on the compression setting information related to the CSI-RS, obtain a first channel state based on the received CSI-RS corresponding to the compressed CSI-RS port, obtain a second channel state corresponding to all or part of the CSI-RS port based on the obtained channel state, and transmit channel state information indicating the second channel state corresponding to all or part of the CSI-RS port to the base station, wherein the compressed CSI-RS port corresponds to a part of the entire CSI-RS port, and the compressed CSI-RS port is based on the entire CSI-RS port and a port switching matrix.

[0016] In addition, a base station of a wireless communication system comprises: a transceiver; and a control unit configured to transmit compression setting information related to a channel state information reference signal (CSI-RS) to a terminal, transmit the CSI-RS corresponding to a compressed CSI-RS port corresponding to the compression setting information related to the CSI-RS to the terminal, and receive channel state information indicating a second channel state corresponding to all or part of the CSI-RS ports from the terminal, wherein the second channel state is derived from a first channel state corresponding to the compressed CSI-RS port, the compressed CSI-RS port corresponds to a part of the entire CSI-RS port, and the compressed CSI-RS port is based on the entire CSI-RS port and a port switching matrix.

[0017] The various embodiments of the present disclosure described above are merely some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by those skilled in the art based on the detailed description to be described below.

[0018] According to one embodiment of the present disclosure, a method and apparatus for compressing and transmitting a channel state information reference signal in a wireless communication system can be provided. Furthermore, according to one embodiment of the present disclosure, by compressing and transmitting the channel state information reference signal, the wireless resource overhead used for transmitting the channel state information reference signal can be reduced.

[0019] 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.

[0020] FIG. 1 is a diagram illustrating the basic structure of a time-frequency domain, which is a wireless resource domain in which data or a control channel is transmitted in a 5G wireless communication system according to one embodiment of the present disclosure.

[0021] FIG. 2 is a drawing illustrating an example of a slot structure used in a 5G wireless communication system according to one embodiment of the present disclosure.

[0022] FIG. 3 is a diagram illustrating an example of a setting for a bandwidth part (BWP) of a 5G wireless communication system according to one embodiment of the present disclosure.

[0023] FIG. 4 is a diagram illustrating an example of a set of control resources to which a downlink control channel is transmitted in a 5G wireless communication system according to one embodiment of the present disclosure.

[0024] FIG. 5 is a diagram illustrating the structure of a downlink control channel of a 5G wireless communication system according to one embodiment of the present disclosure.

[0025] Figure 6 is a diagram illustrating an example of a non-periodic CSI reporting method in a 5G wireless communication system.

[0026] FIG. 7 is a diagram illustrating an example of the concept of AI-based CSI-RS compression to reduce CSI-RS overhead applied to various embodiments of the present disclosure.

[0027] FIG. 8a is a drawing illustrating an example of a port transformation according to one embodiment of the present disclosure.

[0028] FIG. 8b is a drawing illustrating an example of a port transformation index according to one embodiment of the present disclosure.

[0029] FIG. 9 is a diagram illustrating an example of an AI model training process and an AI model inference process in an AI model applied to various embodiments of the present disclosure.

[0030] FIG. 10 is a diagram illustrating an example of an AI-based CSI-RS compression transmission and reception process according to one embodiment of the present disclosure.

[0031] FIG. 11 is a drawing illustrating another example of an AI-based CSI-RS compression transmission and reception process according to one embodiment of the present disclosure.

[0032] FIG. 12 is a diagram illustrating an example of a method for setting port switching index(s) according to frequency resource units in a procedure in which a base station instructs a terminal to a port switching index.

[0033] Figure 13 is a diagram illustrating an example in which a port switching instruction is included in csi-ReportSubConfig based on a CSI sub-report.

[0034] Figure 14a illustrates an example of performing CSI-RS compression using frequency axis diversity.

[0035] FIG. 14b is a diagram illustrating an example of a method for restoring an entire CSI-RS port channel for a CSI-RS port channel compressed in RB units at a terminal.

[0036] FIG. 15a illustrates an example of using a CSI-RS compression technique based on frequency axis aggregation to acquire frequency axis diversity.

[0037] FIG. 15b illustrates an example of a port transformation index including a compression ratio and a port transformation matrix according to frequency resource units when using a CSI-RS compression technique based on frequency axis aggregation for frequency axis diversity acquisition.

[0038] FIG. 16 is a diagram illustrating an example of port switching instructions by frequency resource unit.

[0039] Figure 17a is a diagram illustrating an example of CSI-RS periodic port switching for time axis diversity.

[0040] FIG. 17b is a diagram illustrating an example of a CSI-RS periodic port switching index for time axis diversity.

[0041] Figure 18 is a diagram illustrating an example of a procedure for performing CSI-RS compression using time axis diversity.

[0042] FIG. 19 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0043] FIG. 20 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0044] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0045] In describing the embodiments, technical details that are well known in the art to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0046] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the dimensions of each component do not entirely reflect their actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0047] 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 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, the same reference numerals refer to the same components. Furthermore, in describing the present disclosure, if it is determined that a detailed description of a related function or configuration might unnecessarily obscure the essence of the present disclosure, such detailed description is omitted. Additionally, the terms described below are defined considering their functions in the present disclosure, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout the specification.

[0048] Hereinafter, a base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, eNode B, Node B, BS (base station), radio 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. In this disclosure, a downlink (DL) refers to a wireless transmission path of a signal transmitted by a base station to a terminal, and an uplink (UL) refers to a wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE, LTE-A, or 5G systems may be described as examples below, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technology (5G, new radio, NR) developed after LTE-A may be included therein, and the 5G below may be a concept that includes existing LTE, LTE-A, and other similar services. In addition, the present disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, without significantly departing from the scope of the present disclosure.

[0049] 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 the means of instruction 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).

[0050] 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.

[0051] 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.

[0052] Wireless communication systems are evolving from providing early voice-oriented services to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards like 3GPP’s HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2’s HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE’s 802.16e.

[0053] As a representative example of the above-mentioned broadband wireless communication system, the LTE system employs the OFDM (orthogonal frequency division multiplexing) method for the downlink and the SC-FDMA (single carrier frequency division multiple access) method for the uplink. The above-mentioned multiple access method typically allocates and operates time-frequency resources to be sent for each user so that they do not overlap, that is, so that orthogonality is established, thereby allowing the data or control information of each user to be distinguished.

[0054] As a future communication system following LTE, that is, a 5G communication system, it must be able to freely reflect the diverse requirements of users and service providers, and therefore, services that satisfy various requirements simultaneously must be supported. Services being considered for the 5G communication system include enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra reliability low latency communication (URLC).

[0055] eMBB aims to provide data transmission speeds that are superior to those supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a peak data rate of 20 Gbps in the downlink and 10 Gbps in the uplink from the perspective of a single base station. Furthermore, while providing these peak data rates, the 5G communication system must also provide an increased user-perceived data rate. To satisfy these requirements, it necessitates improvements in various transmission and reception technologies, including enhanced multi-input multi-output (MIMO) transmission technology. Additionally, while LTE transmits signals using a maximum bandwidth of 20 MHz in the 2 GHz band, 5G communication systems can meet the data transmission speeds required by using a frequency bandwidth wider than 20 MHz in frequency bands of 3–6 GHz or above 6 GHz.

[0056] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide IoT, mMTC requires support for the connection of a large number of terminals within a cell, improved terminal coverage, enhanced battery life, and reduced terminal costs. Since IoT provides communication functions by attaching to various sensors and devices, a large number of terminals within a cell (e.g., 1,000,000 terminals / km²) 2 It must be able to support mMTC. In addition, due to the nature of the service, terminals supporting mMTC are likely to be located in dead zones where cells cannot cover, such as building basements, so they may require wider coverage compared to other services provided by the 5G communication system. Terminals supporting mMTC must consist of low-cost devices, and since it is difficult to frequently replace the device's battery, a very long battery life of 10 to 15 years may be required.

[0057] Finally, URLLC is a mission-critical cellular-based wireless communication service. For example, consider services used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts. Therefore, the communication provided by URLLC must offer very low latency and very high reliability. For instance, services supporting URLLC must satisfy an air interface latency of less than 0.5 milliseconds, and simultaneously 10 -5The following packet error rate requirements apply. Therefore, for services supporting URLLC, 5G systems must provide a Transmit Time Interval (TTI) smaller than other services, and at the same time, design considerations may be required to allocate a wide resource in the frequency band to ensure the reliability of the communication link.

[0058] The three 5G services, namely eMBB, URLLC, and mMTC, can be multiplexed and transmitted within a single system. In this case, different transmission and reception techniques and parameters may be used between the services to satisfy the different requirements of each service. Of course, 5G is not limited to the three services mentioned above.

[0059] The frame structure of the 5G system will be explained in more detail below with reference to the drawings.

[0060] Figure 1 is a diagram illustrating an example of the basic structure of the time-frequency domain, which is a wireless resource domain where data or control channels are transmitted in a 5G wireless communication system.

[0061] Referring to FIG. 1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. In the time and frequency domains, the basic unit of a resource is a resource element (RE, 101), which can be defined as one OFDM symbol (102) on the time axis and one subcarrier (103) on the frequency axis. In the frequency domain (For example, 12) consecutive REs can form a resource block (resource block, RB, 104).

[0062] Figure 2 is a drawing illustrating an example of a slot structure used in a 5G wireless communication system.

[0063] Referring to FIG. 2, an example of a frame (200), subframe (201), and slot (202) structure is illustrated. One frame (200) can be defined as 10ms. One subframe (201) can be defined as 1ms, and thus one frame (200) can be composed of a total of 10 subframes (201). One slot (202, 203) can be defined as 14 OFDM symbols (i.e., the number of symbols per slot). = 14). One subframe (201) may be composed of one or more slots (202, 203), and the number of slots (202, 203) per one subframe (201) may vary depending on the setting value μ (204, 205) for the subcarrier spacing. In an example of FIG. 2, cases where μ=0 (204) and μ=1 (205) are shown as the setting value for the subcarrier spacing. When μ=0 (204), one subframe (201) may be composed of one slot (202), and when μ=1 (205), one subframe (201) may be composed of two slots (203). That is, depending on the setting value μ for the subcarrier spacing, the number of slots per one subframe ( ) may vary, and accordingly, the number of slots per frame ( ) may vary. Depending on each subcarrier spacing setting μ and It can be defined as shown in Table 1 below.

[0064] μ 014101114202214404314808414160165143203261464064

[0065] Next, the bandwidth part (BWP) setting in a 5G communication system will be explained in detail with reference to the drawing.

[0066] Figure 3 is a diagram illustrating an example of a configuration for a bandwidth part in a 5G wireless communication system.

[0067] Referring to FIG. 3, an example is illustrated in which the terminal bandwidth (UE bandwidth, 300) is configured into two bandwidth parts, namely Bandwidth Part #1 (BWP#1, 301) and Bandwidth Part #2 (BWP#2, 302). The base station may configure one or more bandwidth parts for the terminal and may configure the following information for each bandwidth part.

[0068] BWP ::= SEQUENCE {bwp-Id BWP-Id,(Bandwidth Identifier)locationAndBandwidth INTEGER (1..65536),(Bandwidth Location)subcarrierSpacing ENUMERATED {n0, n1, n2, n3, n4, n5},(Subcarrier Spacing)cyclicPrefix ENUMERATED { extended}(Cyclical Prefix)}

[0069] Of course, the configuration of the bandwidth part is not limited to the above examples, and various parameters related to the bandwidth part may be configured for the terminal in addition to the configuration information above. The configuration information may be transmitted by the base station to the terminal via higher-layer signaling, for example, radio resource control (RRC) signaling. Among the one or more configured bandwidth parts, at least one bandwidth part may be activated. Whether the configured bandwidth part is activated may be transmitted semi-statically from the base station to the terminal via RRC signaling or dynamically via downlink control information (DCI).

[0070] According to one embodiment, prior to the RRC connection, the terminal may receive an initial bandwidth part (initial BWP) for initial connection from the base station via a master information block (MIB). More specifically, during the initial connection phase, the terminal may receive configuration information for a control resource set (CORESET) and a search space through a physical downlink control channel (PDCCH) transmitted over a physical broadcast channel (PBCH) to receive system information required for initial connection (which may correspond to remaining system information, RMSI, system information block 1, or SIB1). The control resource set and search space configured by the MIB may each be considered as identity (ID) 0. The base station may notify the terminal of configuration information, such as frequency allocation information, time allocation information, and numerology, for control resource set #0 via the MIB. Additionally, the base station may notify the terminal via the MIB of configuration information regarding the monitoring period and occasion for Control Resource Set #0, i.e., configuration information regarding Search Space #0. The terminal may regard the frequency range configured as Control Resource Set #0 obtained from the MIB as an initial bandwidth part for initial access, and through the configured initial bandwidth part, the terminal can receive the PDSCH (physical downlink shared channel) through which SIB1 is transmitted. At this time, the identifier (ID) of the initial bandwidth part may be considered as 0. In addition to receiving SIBs, the initial bandwidth part may also be utilized for other system information (OSI), paging, and random access.

[0071] Next, we will explain the SS / PBCH block (synchronization signal / physical broadcast channel block) in a 5G wireless communication system.

[0072] An SS / PBCH block may refer to a physical layer channel block composed of PSS (primary SS), SSS (secondary SS), and PBCH. Specifically, it may be as follows.

[0073] - PSS: A signal that serves as the reference for downlink time / frequency synchronization and provides some information about the cell ID.

[0074] - SSS: Serves as the reference for downlink time / frequency synchronization and provides the remaining cell ID information not provided by PSS. Additionally, it can serve as a reference signal for PBCH demodulation.

[0075] - PBCH: Provides essential system information required for the transmission and reception of the terminal's data and control channels. The essential system information may include search space-related control information representing wireless resource mapping information of the control channel, scheduling control information for a separate data channel transmitting system information, etc.

[0076] - SS / PBCH block: An SS / PBCH block is composed of a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks may be transmitted within a time of 5ms, and each transmitted SS / PBCH block may be distinguished by an index.

[0077] The terminal can detect PSS and SSS during the initial connection phase and can decode PBCH. It can obtain MIB from PBCH and receive a control resource set #0 (which may correspond to a control resource set with a control resource set index of 0, CORESET0) from it. The terminal can perform monitoring of control resource set #0 by assuming that the selected SS / PBCH block and the demodulation reference signal (DMRS) transmitted from control resource set #0 are quasi-co-located (QCL). The terminal can receive system information based on downlink control information transmitted from control resource set #0. The terminal can obtain configuration information related to the random access channel (RACH) required for initial connection from the received system information. The terminal can transmit a physical RACH (PRACH) to the base station considering the selected SS / PBCH index, and the base station receiving the PRACH can obtain information regarding the SS / PBCH block index selected by the terminal. The base station can know that the terminal has selected a block among the respective SS / PBCH blocks and is monitoring the associated control resource set #0.

[0078] Next, downlink control information (DCI) in 5G wireless communication systems will be explained in detail.

[0079] In a 5G system, scheduling information for uplink data (or physical uplink shared channel (PUSCH)) or downlink data (or physical downlink shared channel (PDSCH)) can be transmitted from a base station to a terminal via DCI. The terminal can monitor a fallback DCI format and a 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.

[0080] DCI can be transmitted via the PDCCH, a physical downlink control channel, 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.

[0081] For example, a DCI scheduling a PDSCH for system information (SI) can be scrambled as SI-RNTI. A DCI scheduling a PDSCH for a random access response (RAR) message can be scrambled as RA-RNTI (random access RNTI). A DCI scheduling a PDSCH for a paging message can be scrambled as P-RNTI (paging RNTI). A DCI notifying a slot format indicator (SFI) can be scrambled as SFI-RNTI (slot format indicator RNTI). A DCI notifying a transmit power control (TPC) can be scrambled as TPC-RNTI (transmit power control RNTI). A DCI that schedules a terminal-specific PDSCH or PUSCH can be scrambled into a C-RNTI (cell RNTI), an MCS-C-RNTI (modulation coding scheme C-RNTI), or a CS-RNTI (configured scheduling RNTI).

[0082] 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, for example, the information in Table 3 below.

[0083] - Identifier for DCI formats - 1 bit - The value of this bit field is always set to 0, indicating an UL DCI format - Frequency domain resource assignment - bits where is defined in subclause 7.3.1.0○ For PUSCH hopping with resource allocation type 1:● N UL_hop MSB bits are used to indicate the frequency offset according to Subclause 6.3 of [6, TS 38.214], where N UL_hop =1 if the higher layer parameter frequencyHoppingOffsetLists contains two offset values and N UL_hop =2 if the higher layer parameter frequencyHoppingOffsetLists contains four offset values● -N UL_hop bits provides the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214]○ For non-PUSCH hopping with resource allocation type 1:● bits provide the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214] - Time domain resource assignment - 4 bits as defined in Subclause 6.1.2.1 of [6, TS 38.214] - Frequency hopping flag - 1 bit according to Table 7.3.1.1.1-3, as defined in Subclause 6.3 of [6, TS 38.214] - Modulation and coding scheme - 5 bits as defined in Subclause 6.1.4.1 of [6, TS 38.214] - New data indicator - 1 bit - Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2 - HARQ process number (HARQ process number) - 4 bits - TPC command for scheduled PUSCH - 2 bits as defined in Subclause 7.1.1 of [5, TS 38.213] - Padding bits, if required. - UL / SUL indicator - 1 bit for UEs configured with supplementaryUplink in ServingCellConfig in the cell as defined in Table 7.3.1.1.1-1 and the number of bits for DCI format 1_0 before padding is larger than the number of bits for DCI format 0_0 before padding; 0 bit otherwise. The UL / SUL indicator, if present, locates in the last bit position of DCI format 0_0, after the padding bit(s).○ If the UL / SUL indicator is present in DCI format 0_0 and the higher layer parameter pusch-Config is not configured on both UL and SUL the UE ignores the UL / SUL indicator field in DCI format 0_0, and the corresponding PUSCH scheduled by the DCI format 0_0 is for the UL or SUL for which high layer parameter pucch-Config is configured;○ If the UL / SUL indicator is not present in DCI format 0_0 and pucch-Config is configured, the corresponding PUSCH scheduled by the DCI format 0_0 is for the UL or SUL for which high layer parameter pucch-Config is configured.○ If the UL / SUL indicator is not present in DCI format 0_0 and pucch-Config is not configured, the corresponding PUSCH scheduled by the DCI format 0_0 is for the uplink on which the latest PRACH is transmitted.

[0084] 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, for example, the information in Table 4 below.

[0085] - Identifier for DCI formats (DCI 포맷 식별자) - 1 bit- The value of this bit field is always set to 0, indicating an UL DCI format- Carrier indicator (캐리어 지시자) - 0 or 3 bits, as defined in Subclause 10.1 of [5, TS38.213].- UL / SUL indicator (상향링크 / 추가적인 상향링크(Supplementary UL) 지시자) - 0 bit for UEs not configured with supplementaryUplink in ServingCellConfig in the cell or UEs configured with supplementaryUplink in ServingCellConfig in the cell but only PUCCH carrier in the cell is configured for PUSCH transmission; otherwise, 1 bit as defined in Table 7.3.1.1.1-1.- Bandwidth part indicator (대역폭파트 지시자) - 0, 1 or 2 bits as determined by the number of UL BWPs n BWP,RRC configured by higher layers, excluding the initial UL bandwidth part. The bitwidth for this field is determined as bits, where○ n BWP = n BWP,RRC if n BWP,RRC ≤3 , in which case the bandwidth part indicator is equivalent to the ascending order of the higher layer parameter BWP-Id;○ otherwise nBWP = n BWP,RRC , in which case the bandwidth part indicator is defined in Table 7.3.1.1.2-1;If a UE does not support active BWP change via DCI, the UE ignores this bit field.- Frequency domain resource assignment (주파수 도메인 자원 할당) - number of bits determined by the following, where is the size of the active UL bandwidth part:○ N RBG bits if only resource allocation type 0 is configured, where N RBG is defined in Subclause 6.1.2.2.1 of [6, TS 38.214],○ bits if only resource allocation type 1 is configured, or max( ,N RBG )+1 bits if both resource allocation type 0 and 1 are configured.○ If both resource allocation type 0 and 1 are configured, the MSB bit is used to indicate resource allocation type 0 or resource allocation type 1, where the bit value of 0 indicates resource allocation type 0 and the bit value of 1 indicates resource allocation type 1.○ For resource allocation type 0, the N RBGLSBs provide the resource allocation as defined in Subclause 6.1.2.2.1 of [6, TS 38.214].○ For resource allocation type 1, the LSBs provide the resource allocation as follows:● For PUSCH hopping with resource allocation type 1:□ N UL_hop MSB bits are used to indicate the frequency offset according to Subclause 6.3 of [6, TS 38.214], where N UL_hop =1 if the higher layer parameter frequencyHoppingOffsetLists contains two offset values and N UL_hop =2 if the higher layer parameter frequencyHoppingOffsetLists contains four offset values□ -N UL_hop bits provides the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214]● For non-PUSCH hopping with resource allocation type 1:□ bits provides the frequency domain resource allocation according to Subclause 6.1.2.2.2 of [6, TS 38.214]If "Bandwidth part indicator" field indicates a bandwidth part other than the active bandwidth part and if both resource allocation type 0 and 1 are configured for the indicated bandwidth part, the UE assumes resource allocation type 0 for the indicated bandwidth part if the bitwidth of the "Frequency domain resource assignment" field of the active bandwidth part is smaller than the bitwidth of the "Frequency domain resource assignment" field of the indicated bandwidth part.- Time domain resource assignment (시간 도메인 자원 할당) - 0, 1, 2, 3, or 4 bits as defined in Subclause 6.1.2.1 of [6, TS38.214]. The bitwidth for this field is determined as bits, where I is the number of entries in the higher layer parameter pusch-TimeDomainAllocationList if the higher layer parameter is configured; otherwise I is the number of entries in the default table.- Frequency hopping flag - 0 or 1 bit: ○ 0 bit if only resource allocation type 0 is configured or if the higher layer parameter frequencyHopping is not configured; ○ 1 bit according to Table 7.3.1.1.1-3 otherwise, only applicable to resource allocation type 1, as defined in Subclause 6.3 of [6, TS 38.214]. - Modulation and coding scheme - 5 bits as defined in Subclause 6.1.4.1 of [6, TS 38.214] - New data indicator - 1 bit - Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2 - HARQ process number - 4 bits - 1st downlink assignment index - 1 or 2 bits: ○ 1 bit for semi-static HARQ-ACK codebook; 2 bits for dynamic HARQ-ACK codebook. - 2nd downlink assignment index - 0 or 2 bits: 2 bits for dynamic HARQ-ACK codebook with two HARQ-ACK sub-codebooks; 0 bit otherwise. - TPC command for scheduled PUSCH - 2 bits as defined in Subclause 7.1.1 of [5, TS38.213]- SRS resource indicator (사운딩 기준 신호(Sounding Reference Signal; SRS) 자원 지시자) -. or bits, where N SRS is the number of configured SRS resources in the SRS resource set associated with the higher layer parameter usage of value 'codeBook' or 'nonCodeBook',○ bits according to Tables 7.3.1.1.2-28 / 29 / 30 / 31 if the higher layer parameter txConfig = nonCodebook, where N SRS is the number of configured SRS resources in the SRS resource set associated with the higher layer parameter usage of value 'nonCodeBook' and● if UE supports operation with maxMIMO-Layers and the higher layer parameter maxMIMO-Layers of PUSCH-ServingCellConfig of the serving cell is configured, L max is given by that parameter● otherwise, L max is given by the maximum number of layers for PUSCH supported by the UE for the serving cell for non-codebook based operation.○ bits according to Tables 7.3.1.1.2-32 if the higher layer parameter txConfig = codebook, where N SRSis the number of configured SRS resources in the SRS resource set associated with the higher layer parameter usage of value 'codeBook'.- Precoding information and number of layers (프리코딩 정보 및 레이어 개수) - number of bits determined by the following:○ 0 bits if the higher layer parameter txConfig = nonCodeBook;○ 0 bits for 1 antenna port and if the higher layer parameter txConfig = codebook;○ 4, 5, or 6 bits according to Table 7.3.1.1.2-2 for 4 antenna ports, if txConfig = codebook, and according to whether transform precoder is enabled or disabled, and the values of higher layer parameters maxRank, and codebookSubset;○ 2, 4, or 5 bits according to Table 7.3.1.1.2-3 for 4 antenna ports, if txConfig = codebook, and according to whether transform precoder is enabled or disabled, and the values of higher layer parameters maxRank, and codebookSubset;○ 2 or 4 bits according to Table7.3.1.1.2-4 for 2 antenna ports, if txConfig = codebook, and according to whether transform precoder is enabled or disabled, and the values of higher layer parameters maxRank and codebookSubset;○ 1 or 3 bits according to Table7.3.1.1.2-5 for 2 antenna ports, if txConfig = codebook, and according to whether transform precoder is enabled or disabled, and the values of higher layer parameters maxRank and codebookSubset.- Antenna ports (안테나 포트) - number of bits determined by the following○ 2 bits as defined by Tables 7.3.1.1.2-6, if transform precoder is enabled, dmrs-Type=1, and maxLength=1;○ 4 bits as defined by Tables 7.3.1.1.2-7, if transform precoder is enabled, dmrs-Type=1, and maxLength=2;○ 3 bits as defined by Tables 7.3.1.1.2-8 / 9 / 10 / 11, if transform precoder is disabled, dmrs-Type=1, and maxLength=1, and the value of rank is determined according to the SRS resource indicator field if the higher layer parameter txConfig = nonCodebook and according to the Precoding information and number of layers field if the higher layer parameter txConfig = codebook;○ 4 bits as defined by Tables 7.3.1.1.2-12 / 13 / 14 / 15, if transform precoder is disabled, dmrs-Type=1, and maxLength=2, and the value of rank is determined according to the SRS resource indicator field if the higher layer parameter txConfig = nonCodebook and according to the Precoding information and number of layers field if the higher layer parameter txConfig = codebook;○ 4 bits as defined by Tables 7.3.1.1.2-16 / 17 / 18 / 19, if transform precoder is disabled, dmrs-Type=2, and maxLength=1, and the value of rank is determined according to the SRS resource indicator field if the higher layer parameter txConfig = nonCodebook and according to the Precoding information and number of layers field if the higher layer parameter txConfig = codebook;○ 5 bits as defined by Tables 7.3.1.1.2-20 / 21 / 22 / 23, if transform precoder is disabled, dmrs-Type=2, and maxLength=2, and the value of rank is determined according to the SRS resource indicator field if the higher layer parameter txConfig = nonCodebook and according to the Precoding information and number of layers field if the higher layer parameter txConfig = codebook.where the number of CDM groups without data of values 1, 2, and 3 in Tables 7.3.1.1.2-6 to 7.3.1.1.2-23 refers to CDM groups {0}, {0,1}, and {0, 1,2} respectively.- SRS request (SRS 요청) - 2 bits as defined by Table 7.3.1.1.2-24 for UEs not configured with supplementaryUplink in ServingCellConfig in the cell; 3 bits for UEs configured with supplementaryUplink in ServingCellConfig in the cell where the first bit is the non-SUL / SUL indicator as defined in Table 7.3.1.1.1-1 and the second and third bits are defined by Table 7.3.1.1.2-24. This bit field may also indicate the associated CSI-RS according to Subclause 6.1.1.2 of [6, TS 38.214].- CSI request (채널 상태 정보 (Channel State Information; CSI) 요청) - 0, 1, 2, 3, 4, 5, or 6 bits determined by higher layer parameter reportTriggerSize.- CBG transmission information (CBGTI) (코드 불록 그룹(Code Block Group; CBG) 전송 정보) - 0 bit if higher layer parameter codeBlockGroupTransmission for PDSCH is not configured, otherwise, 2, 4, 6, or 8 bits determined by higher layer parameter maxCodeBlockGroupsPerTransportBlock for PUSCH.- PTRS-DMRS association (위상 트래킹 기준 신호(Phase Tracking Reference Signal)-복조 기준 신호 (Demodulation Reference Signal) 관계) - number of bits determined as follows○ 0 bit if PTRS-UplinkConfig is not configured and transform precoder is disabled, or if transform precoder is enabled, or if maxRank=1;○ 2 bits otherwise, where Table 7.3.1.1.2-25 and 7.3.1.1.2-26 are used to indicate the association between PTRS port(s) and DMRS port(s) for transmission of one PT-RS port and two PT-RS ports respectively, and the DMRS ports are indicated by the Antenna ports field.If "Bandwidth part indicator" field indicates a bandwidth part other than the active bandwidth part and the "PTRS-DMRS association" field is present for the indicated bandwidth part but not present for the active bandwidth part, the UE assumes the "PTRS-DMRS association" field is not present for the indicated bandwidth part.- beta_offset indicator (beta offset indicator) - 0 if the higher layer parameter betaOffsets = semiStatic; otherwise 2 bits as defined by Table 9.3-3 in [5, TS 38.213].- DMRS sequence initialization (demodulation reference signal sequence initialization) - 0 bit if transform precoder is enabled; 1 bit if transform precoder is disabled.- UL-SCH indicator (Uplink-Data Channel (UL-SCH) indicator) - 1 bit. A value of "1" indicates UL-SCH shall be transmitted on the PUSCH and a value of "0" indicates UL-SCH shall not be transmitted on the PUSCH. Except for DCI format 0_1 ​​with CRC scrambled by SP-CSI-RNTI, a UE is not expected to receive a DCI format 0_1 ​​with UL-SCH indicator of "0" and CSI request of all zero(s).

[0086] 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, for example, the information in Table 5 below.

[0087] - Identifier for DCI formats - 1 bit - The value of this bit field is always set to 1, indicating a DCI format - Frequency domain resource assignment - bits where is given by subclause 7.3.1.0If the CRC of the DCI format 1_0 is scrambled by C-RNTI and the "Frequency domain resource assignment" field are of all ones, the DCI format 1_0 is for random access procedure initiated by a PDCCH order, with all remaining fields set as follows:- Random Access Preamble index (랜덤 엑세스 프리엠블 인덱스) -6 bits according to ra-PreambleIndex in Subclause 5.1.2 of [8, TS38.321]- UL / SUL indicator (상향링크 / 추가적인 상향링크(Supplementary UL) 지시자) - 1 bit. If the value of the "Random Access Preamble index" is not all zeros and if the UE is configured with supplementaryUplink in ServingCellConfig in the cell, this field indicates which UL carrier in the cell to transmit the PRACH according to Table 7.3.1.1.1-1; otherwise, this field is reserved- SS / PBCH index (동기신호(Synchronization Signal; SS) / 브로드캐스트채널(Physical Broadcast Channel; PBCH) 인덱스) - 6 bits.If the value of the "Random Access Preamble index" is not all zeros, this field indicates the SS / PBCH that shall be used to determine the RACH occasion for the PRACH transmission; otherwise, this field is reserved.- PRACH Mask index (랜덤엑세스 채널(Physical Random Access Channel; PRACH) 마스크 인덱스) - 4 bits. If the value of the "Random Access Preamble index" is not all zeros, this field indicates the RACH occasion associated with the SS / PBCH indicated by "SS / PBCH index" for the PRACH transmission, according to Subclause 5.1.1 of [8, TS38.321]; otherwise, this field is reserved- Reserved bits (예비 비트) - 10 bitsOtherwise, all remaining fields are set as follows:- Time domain resource assignment (시간 도메인 자원할당) - 4 bits as defined in Subclause 5.1.2.1 of [6, TS 38.214]- VRB-to-PRB mapping (가상 자원 블록(virtual resource block)-to-물리 자원 블록(physical resource block) 매핑) - 1 bit according to Table 7.3.1.2.2-5- Modulation and coding scheme (변조 코딩 스킴) - 5 bits as defined in Subclause 5.1.3 of [6, TS 38.214]- New data indicator - 1 bit- Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2- HARQ process number - 4 bits- Downlink assignment index - 2 bits as defined in Subclause 9.1.3 of [5, TS 38.213], as counter DAI- TPC command for scheduled PUCCH - 2 bits as defined in Subclause 7.2.1 of [5, TS 38.213]- PUCCH resource indicator - 3 bits as defined in Subclause 9.2.3 of [5, TS 38.213]- PDSCH-to-HARQ_feedback timing indicator (PDSCH-to-HARQ feedback timing indicator) - 3 bits as defined in Subclause 9.2.3 of [5, TS38.213].

[0088] 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, for example, the information in Table 6 below.

[0089] - Identifier for DCI formats (DCI 포맷 식별자) - 1 bits○ The value of this bit field is always set to 1, indicating a DL DCI format- Carrier indicator (캐리어 지시자) - 0 or 3 bits as defined in Subclause 10.1 of [5, TS 38.213].- Bandwidth part indicator (대역폭파트 지시자) - 0, 1 or 2 bits as determined by the number of DL BWPs n BWP,RRC configured by higher layers, excluding the initial DL bandwidth part. The bitwidth for this field is determined as bits, where○ n BWP = n BWP,RRC if n BWP,RRC ≤3, in which case the bandwidth part indicator is equivalent to the ascending order of the higher layer parameter BWP-Id;○ otherwise n BWP = n BWP,RRC , in which case the bandwidth part indicator is defined in Table 7.3.1.1.2-1;If a UE does not support active BWP change via DCI, the UE ignores this bit field.- Frequency domain resource assignment (주파수 도메인 자원 할당) - number of bits determined by the following, where is the size of the active DL bandwidth part:○ N RBG bits if only resource allocation type 0 is configured, where N RBG is defined in Subclause 5.1.2.2.1 of [6, TS38.214],○ bits if only resource allocation type 1 is configured, or○ max( ,N RBG )+1 bits if both resource allocation type 0 and 1 are configured.○ If both resource allocation type 0 and 1 are configured, the MSB bit is used to indicate resource allocation type 0 or resource allocation type 1, where the bit value of 0 indicates resource allocation type 0 and the bit value of 1 indicates resource allocation type 1.○ For resource allocation type 0, the N RBG LSBs provide the resource allocation as defined in Subclause 5.1.2.2.1 of [6, TS 38.214].○ For resource allocation type 1, the LSBs provide the resource allocation as defined in Subclause 5.1.2.2.2 of [6, TS 38.214]If "Bandwidth part indicator" field indicates a bandwidth part other than the active bandwidth part and if both resource allocation type 0 and 1 are configured for the indicated bandwidth part, the UE assumes resource allocation type 0 for the indicated bandwidth part if the bitwidth of the "Frequency domain resource assignment" field of the active bandwidth part is smaller than the bitwidth of the "Frequency domain resource assignment" field of the indicated bandwidth part.- Time domain resource assignment (시간 도메인 자원 할당) - 0, 1, 2, 3, or 4 bits as defined in Subclause 5.1.2.1 of [6, TS 38.214]. The bitwidth for this field is determined as bits, where I is the number of entries in the higher layer parameter pdsch-TimeDomainAllocationList if the higher layer parameter is configured; otherwise I is the number of entries in the default table.- VRB-to-PRB mapping (가상 자원 블록(virtual resource block)-to-물리 자원 블록(physical resource block) 매핑) - 0 or 1 bit:○ 0 bit if only resource allocation type 0 is configured or if interleaved VRB-to-PRB mapping is not configured by high layers;○ 1 bit according to Table 7.3.1.2.2-5 otherwise, only applicable to resource allocation type 1, as defined in Subclause 7.3.1.6 of [4, TS 38.211].- PRB bundling size indicator (PRB 번들링 크기 지시자) - 0 bit if the higher layer parameter prb-BundlingType is not configured or is set to 'static', or 1 bit if the higher layer parameter prb-BundlingType is set to 'dynamic' according to Subclause 5.1.2.3 of [6, TS 38.214].- Rate matching indicator (레이트매칭 지시자) - 0, 1, or 2 bits according to higher layer parameters rateMatchPatternGroup1 and rateMatchPatternGroup2, where the MSB is used to indicate rateMatchPatternGroup1 and the LSB is used to indicate rateMatchPatternGroup2 when there are two groups.- ZP CSI-RS trigger (Zero Power Channel State Information Reference Signal Trigger) - 0, 1, or 2 bits as defined in Subclause 5.1.4.2 of [6, TS 38.214]. The bitwidth for this field is determined as bits, where is the number of aperiodic ZP CSI-RS resource sets configured by a higher layer. For transport block 1: - Modulation and coding scheme - 5 bits as defined in Subclause 5.1.3.1 of [6, TS 38.214] - New data indicator - 1 bit - Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2. For transport block 2 (only present if maxNrofCodeWordsScheduledByDCI equals 2): - Modulation and coding scheme - 5 bits as defined in Subclause 5.1.3.1 of [6, TS 38.214] - New data indicator - 1 bit - Redundancy version - 2 bits as defined in Table 7.3.1.1.1-2If "Bandwidth part indicator" field indicates a bandwidth part other than the active bandwidth part and the value of maxNrofCodeWordsScheduledByDCI for the indicated bandwidth part equals 2 and the value of maxNrofCodeWordsScheduledByDCI for the active bandwidth part equals 1, the UE assumes zeros are padded when interpreting the "Modulation and coding scheme", "New data indicator", and "Redundancy version" fields of transport block 2 according to Subclause 12 of [5, TS38.213], and the UE ignores the "Modulation and coding scheme", "New data indicator", and "Redundancy version" fields of transport block 2 for the indicated bandwidth part.- HARQ process number (HARQ 프로세스 번호) -○ 4 bits- Downlink assignment index (하향링크 할당 인덱스) - number of bits as defined in the following○ 4 bits if more than one serving cell are configured in the DL and the higher layer parameter pdsch-HARQ-ACK-Codebook=dynamic, where the 2 MSB bits are the counter DAI and the 2 LSB bits are the total DAI;○ 2 bits if only one serving cell is configured in the DL and the higher layer parameter pdsch-HARQ-ACK-Codebook=dynamic, where the 2 bits are the counter DAI;○ 0 bits otherwise.- TPC command for scheduled PUCCH (스케쥴링된 PUCCH에 대한 전송 전력 제어 명령) - 2 bits as defined in Subclause 7.2.1 of [5, TS 38.213]- PUCCH resource indicator (PUCCH 자원 지시자) - 3 bits as defined in Subclause 9.2.3 of [5, TS 38.213]- PDSCH-to-HARQ_feedback timing indicator (PDSCH-to-HARQ 타이밍 지시자) - 0, 1, 2, or 3 bits as defined in Subclause 9.2.3 of [5, TS 38.213]. The bitwidth for this field is determined as bits, where I is the number of entries in the higher layer parameter dl-DataToUL-ACK.- Antenna port(s) (안테나 포트) - 4, 5, or 6 bits as defined by Tables 7.3.1.2.2-1 / 2 / 3 / 4, where the number of CDM groups without data of values 1, 2, and 3 refers to CDM groups {0}, {0,1}, and {0, 1,2} respectively. The antenna ports. shall be determined according to the ordering of DMRS port(s) given by Tables 7.3.1.2.2-1 / 2 / 3 / 4.- Transmission configuration indication (전송 설정 지시자) - 0 bit if higher layer parameter tci-PresentInDCI is not enabled; otherwise 3 bits as defined in Subclause 5.1.5 of [6, TS38.214].If "Bandwidth part indicator" field indicates a bandwidth part other than the active bandwidth part,- if the higher layer parameter tci-PresentInDCI is not enabled for the CORESET used for the PDCCH carrying the DCI format 1_1,○ the UE assumes tci-PresentInDCI is not enabled for all CORESETs in the indicated bandwidth part;- otherwise,○ the UE assumes tci-PresentInDCI is enabled for all CORESETs in the indicated bandwidth part.- SRS request (SRS 요청) - 2 bits as defined by Table 7.3.1.1.2-24 for UEs not configured with supplementaryUplink in ServingCellConfig in the cell; 3 bits for UEs configured with supplementaryUplink in ServingCellConfig in the cell where the first bit is the non-SUL / SUL indicator as defined in Table 7.3.1.1.1-1 and the second and third bits are defined by Table 7.3.1.1.2-24. This bit field may also indicate the associated CSI-RS according to Subclause 6.1.1.2 of [6, TS 38.214].- CBG transmission information (CBGTI) (코드 블록 그룹 전송 정보) - 0 bit if higher layer parameter codeBlockGroupTransmission for PDSCH is not configured, otherwise, 2, 4, 6, or 8 bits as defined in Subclause 5.1.7 of [6, TS38.214], determined by the higher layer parameters maxCodeBlockGroupsPerTransportBlock and maxNrofCodeWordsScheduledByDCI for the PDSCH.- CBG flushing out information (CBGFI) (코드 블록 그룹 플러싱 아웃 정보) - 1 bit if higher layer parameter codeBlockGroupFlushIndicator is configured as "TRUE", 0 bit otherwise.- DMRS sequence initialization (복조 기준 신호 시퀀스 초기화) - 1 bit.

[0090] The following describes the time domain resource allocation method for data channels in a 5G wireless communication system.

[0091] The base station may set a table for time domain resource allocation information for the downlink data channel (PDSCH) and uplink data 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. Time domain resource allocation information may include, for example, 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 regarding the position and length of the starting 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 7 and 8 below may be notified from the base station to the terminal.

[0092] PDSCH-TimeDomainResourceAllocationListinformation elementPDSCH-TimeDomainResourceAllocationList ::= SEQUENCE (SIZE(1..maxNrofDL-Allocations)) OF PDSCH-TimeDomainResourceAllocationPDSCH-TimeDomainResourceAllocation ::= SEQUENCE {k0 INTEGER(0..32) OPTIONAL, -- Need S(PDCCH-to-PDSCH timing, slots)mappingType ENUMERATED {typeA, typeB},(PDSCH mapping type)startSymbolAndLength INTEGER (0..127)(start symbol and length of PDSCH)}

[0093] PUSCH-TimeDomainResourceAllocationinformation elementPUSCH-TimeDomainResourceAllocationList ::= SEQUENCE (SIZE(1..maxNrofUL-Allocations)) OF PUSCH-TimeDomainResourceAllocationPUSCH-TimeDomainResourceAllocation ::= SEQUENCE {k2 INTEGER(0..32) OPTIONAL, -- Need S(PDCCH-to-PUSCH timing, slots)mappingType ENUMERATED {typeA, typeB},(PUSCH mapping type)startSymbolAndLength INTEGER (0..127)(start symbol and length of PUSCH)}

[0094] The base station may notify the terminal of one of the entries in the table for time domain resource allocation information via L1 signaling (e.g., DCI) (e.g., by indicating the 'time domain resource allocation' field within the DCI). Based on the DCI received from the base station, the terminal may obtain time domain resource allocation information for PDSCH or PUSCH.

[0095] The following describes the frequency domain resource allocation method for data channels in a 5G wireless communication system.

[0096] In a 5G wireless communication system, two types, resource allocation type 0 and resource allocation type 1, are supported as methods for indicating frequency domain resource allocation information for downlink data channels and uplink data channels.

[0097] The base station can set the resource allocation type to the terminal through upper layer signaling (for example, the upper layer parameter resourceAllocation can be set to one of resourceAllocationType0, resourceAllocationType1, or dynamicSwitch). If the terminal is set to both resource allocation types 0 and 1 (or if the upper layer parameter resourceAllocation is similarly set to dynamicSwitch), the base station can indicate whether the bit corresponding to the MSB (most significant bit) of the resource allocation field within the DCI format that directs scheduling is resource allocation type 0 or resource allocation type 1. Additionally, based on the indicated resource allocation type, resource allocation information can be indicated through the remaining bits excluding the bit corresponding to the MSB, and the terminal can interpret the resource allocation field information of the DCI field based on this. If the terminal is set to either resource allocation type 0 or resource allocation type 1 (or if the upper layer parameter resourceAllocation is set to either resourceAllocationType0 or resourceAllocationType1), resource allocation information may be indicated based on the resource allocation type in which the resource allocation field in the DCI format instructing scheduling is set, and the terminal may interpret the resource allocation field information of the DCI field based on this.

[0098] In the following, the downlink control channel in a 5G wireless communication system will be explained in more detail with reference to the drawings.

[0099] Figure 4 is a diagram illustrating an example of a set of control resources transmitted by a downlink control channel in a 5G wireless communication system.

[0100] Referring to FIG. 4, two control resource sets (control resource set #1 (401), control resource set #2 (402)) can be set within the terminal's bandwidth part (UE bandwidth part, 410) on the frequency axis and within one slot (420) on the time axis. The control resource sets (401, 402) can be set to a specific frequency resource (403) within the entire terminal bandwidth part (410) on the frequency axis. Additionally, the control resource sets (401, 402) can be set to one or more OFDM symbols on the time axis, which can be defined as the control resource set duration (404). Referring to the example illustrated in FIG. 4, control resource set #1 (401) is set to a control resource set duration of 2 symbols, and control resource set #2 (402) is set to a control resource set duration of 1 symbol.

[0101] In the aforementioned 5G wireless communication system, a control resource set can be configured by a base station to a terminal through upper-layer signaling (e.g., system information, MIB, RRC signaling). Configuring a control resource set to a terminal means providing information such as the control resource set identifier, the frequency location of the control resource set, and the symbol length of the control resource set. For example, it may include the following information.

[0102] ControlResourceSet ::= SEQUENCE {-- Corresponds to L1 parameter 'CORESET-ID'controlResourceSetId ControlResourceSetId,(ControlResourceSetIdentifier(Identity))frequencyDomainResources BIT STRING (SIZE (45)),(FrequencyAxisResourceAllocationInfo)duration INTEGER (1..maxCoReSetDuration),(TimeAxisResourceAllocationInfo)cce-REG-MappingType CHOICE {(CCE-to-REG MappingType)interleaved SEQUENCE {reg-BundleSize ENUMERATED {n2, n3, n6},(REG Bundle Size)precoderGranularity ENUMERATED {sameAsREG-bundle, allContiguousRBs},interleaverSize ENUMERATED {n2, n3, n6}(Interleaver Size)shiftIndex INTEGER(0..maxNrofPhysicalResourceBlocks-1) OPTIONAL(Interleaved Shift)},nonInterleaved NULL},tci-StatesPDCCH SEQUENCE(SIZE (1..maxNrofTCI-StatesPDCCH)) OF TCI-StateId OPTIONAL,(QCL setting information)tci-PresentInDCI ENUMERATED {enabled} OPTIONAL, -- Need S}

[0103] In Table 9, the tci-StatesPDCCH (simply named TCI (transmission configuration indication) state) configuration information may include information on one or more SS / PBCH block indices or CSI-RS (channel state information reference signal) indices that are in a relationship with DMRS and QCL transmitted from the corresponding control resource set. FIG. 5 is a diagram illustrating an example of the structure of a downlink control channel of a 5G wireless communication system. FIG. 5 illustrates an example of the basic unit of time and frequency resources that constitute a downlink control channel that can be used in a 5G wireless communication system.

[0104] Referring to FIG. 5, the basic unit of time and frequency resources constituting a control channel can be called a REG (resource element group, 503), and the REG (503) can be defined as 1 OFDM symbol (501) on the time axis and 1 PRB (physical resource block, 502) on the frequency axis, i.e., 12 subcarriers. A base station can concatenate REGs (503) to form a downlink control channel allocation unit.

[0105] As illustrated in FIG. 5, if the basic unit to which a downlink control channel is allocated in a 5G wireless communication system is called a CCE (control channel element, 504), then 1 CCE (504) can be composed of multiple REGs (503). For example, if the REG (503) illustrated in FIG. 5 is described, the REG (503) can be composed of 12 REs, and if 1 CCE (504) is composed of 6 REGs (503), then 1 CCE (504) can be composed of 72 REs. When a downlink control resource set is established, the corresponding area can be composed of multiple CCEs (504), and a specific downlink control channel can be mapped to one or multiple CCEs (504) and transmitted according to the aggregation level (AL) within the control resource set. The CCEs (504) in the control resource set are distinguished by numbers, and the numbers of the CCEs (504) can be assigned according to a logical mapping method.

[0106] The basic unit of the downlink control channel, namely the REG (503) shown in FIG. 5, may include both the REs to which the DCI is mapped and the DMRS (505), which is a reference signal for decoding, to which the area is mapped. As shown in FIG. 5, three DMRS (505) may be transmitted within one REG (503). The number of CCEs required to transmit the PDCCH may be 1, 2, 4, 8, or 16 depending on the aggregation level, and different numbers of CCEs may be used to implement link adaptation of the downlink control channel. For example, when AL=L, one downlink control channel may be transmitted through L CCEs. The terminal must detect the signal without knowing information about the downlink control channel, and a search space representing a set of CCEs is defined for blind decoding. A search space is a set of downlink control channel candidates consisting of CCEs that a terminal must attempt to decode on a given aggregation level, and since there are various aggregation levels that form a group of 1, 2, 4, 8, or 16 CCEs, a terminal may have multiple search spaces. A search space set can be defined as a set of search spaces on all configured aggregation levels.

[0107] Search spaces can be classified into common search spaces and UE-specific search spaces. A certain group of terminals or all terminals may examine the common search space of the PDCCH to receive cell-common control information, such as dynamic scheduling or paging messages regarding system information. For example, PDSCH scheduling allocation information for the transmission of SIBs containing cell operator information can be received 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 can be defined as a set of pre-agreed CCEs. Scheduling allocation information for a UE-specific PDSCH or PUSCH can be received by examining the UE-specific search space of the PDCCH. The UE-specific search space can be defined specifically as a function of the terminal's identity and various system parameters.

[0108] In a 5G wireless communication system, parameters for the search space for a PDCCH can be configured from the base station to the terminal via upper-layer signaling (e.g., SIB, MIB, RRC signaling). For example, the base station may configure the terminal 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 index of the control resource set to be monitored in the search space. For example, parameters for the search space for a PDCCH may include the information in Table 10 below.

[0109] SearchSpace ::= SEQUENCE {-- Identity of the search space. SearchSpaceId = 0 identifies the SearchSpace configured via PBCH (MIB) or ServingCellConfigCommon.searchSpaceId SearchSpaceId,(search space identifier)controlResourceSetId ControlResourceSetId,(control resource set identifier)monitoringSlotPeriodicityAndOffset CHOICE {(monitoring slot level period)sl1 NULL,sl2 INTEGER (0..1),sl4 INTEGER (0..3),sl5 INTEGER (0..4),sl8 INTEGER (0..7),sl10 INTEGER (0..9),sl16 INTEGER (0..15),sl20 INTEGER (0..19)} OPTIONAL,duration(monitoring length) INTEGER (2..2559)monitoringSymbolsWithinSlot BIT STRING (SIZE (14)) OPTIONAL,(슬롘 내 나이스 심보)nrofCandidates SEQUENCE {(집성 별보 PDCCH 이리군 수)aggregationLevel1 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel2 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel4 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel8 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8},aggregationLevel16 ENUMERATED {n0, n1, n2, n3, n4, n5, n6, n8}},searchSpaceType CHOICE {(தமாற்க்குக்க்கு திய்தை)-- Configures this search space as common search space (CSS) and DCI formats to monitor.common SEQUENCE {(공통이이국이)}ue-Specific SEQUENCE {(단말-특정이스국)-- Indicates whether the UE monitors in this USS for DCI formats 0-0 and 1-0 or for formats 0-1 and 1-1.formats ENUMERATED {formats0-0-And-1-0, formats0-1-And-1-1},...}.

[0110] According to the configuration information, the base station may configure one or more sets of search spaces for the terminal. According to one embodiment, the base station may configure search space set 1 and search space set 2 for the terminal, configure DCI format A scrambled with X-RNTI in search space set 1 to be monitored in the common search space, and configure DCI format B scrambled with Y-RNTI in search space set 2 to be monitored in the terminal-specific search space. According to the configuration information, one or more sets of search spaces may exist in the common search space or the terminal-specific search space. For example, search space set #1 and search space set #2 may be configured as the common search space, and search space set #3 and search space set #4 may be configured as the terminal-specific search space.

[0111] In the common search space, the following combinations of DCI formats and RNTI can be monitored. Of course, they are not limited to the examples below.

[0112] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, MCS-C-RNTI, SP-CSI-RNTI, RA-RNTI, TC-RNTI, P-RNTI, SI-RNTI

[0113] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0114] - DCI format 2_1 with CRC scrambled by INT-RNTI

[0115] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0116] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0117] In terminal-specific search spaces, the following combinations of DCI formats and RNTI can be monitored. Of course, they are not limited to the examples below.

[0118] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0119] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0120] The specified RNTIs may follow the definitions and uses below.

[0121] C-RNTI: Used for terminal-specific PDSCH scheduling

[0122] MCS-C-RNTI: Used for terminal-specific PDSCH scheduling

[0123] TC-RNTI (temporary cell RNTI): Used for terminal-specific PDSCH scheduling

[0124] CS-RNTI (configured scheduling RNTI): Used for semi-statically configured terminal-specific PDSCH scheduling.

[0125] RA-RNTI: Used for PDSCH scheduling in the random access phase

[0126] P-RNTI: Used for PDSCH scheduling where paging is transmitted

[0127] SI-RNTI (System Information RNTI): Used for PDSCH scheduling where system information is transmitted.

[0128] INT-RNTI (interruption RNTI): Used to indicate whether PDSCH is pucturing.

[0129] TPC-PUSCH-RNTI (transmit power control for PUSCH RNTI): Used to instruct power control commands to the PUSCH

[0130] TPC-PUCCH-RNTI (transmit power control for PUCCH RNTI): Used to instruct power control commands to the PUCCH

[0131] TPC-SRS-RNTI (transmit power control for SRS RNTI): Used to instruct power control commands for the SRS (sounding reference signal).

[0132] The aforementioned specified DCI formats may follow the definitions in Table 11 below.

[0133] DCI formatUsage0_0Scheduling of PUSCH in one cell0_1Scheduling of PUSCH in one cell1_0Scheduling of PDSCH in one cell1_1Scheduling of PDSCH in one cell2_0Notifying a group of UEs of the slot format2_1Notifying a group of UEs of the PRB(s) and OFDM symbol(s) where UE may assume no transmission is intended for the UE2_2Transmission of TPC commands for PUCCH and PUSCH2_3Transmission of a group of TPC commands for SRS transmissions by one or more UEs

[0134] In a 5G system, the search space of aggregation level L in CORESET p and search space set s can be expressed as Equation 1 below.

[0135] [Mathematical Formula 1]

[0136]

[0137] - L: Lamination Level

[0138] - n CI : Carrier Index

[0139] - n CCE,p : Total number of CCEs existing in CORESET p

[0140] - : Slot Index

[0141] - : Number of PDCCH candidates at assembly level L

[0142] - = 0, ..., -1: PDCCH candidate index of aggregation level L

[0143] - l = 0, ..., L -1

[0144] - , Y p,-1 = nRNTI≠0, A p = 39827 for p mod 3 = 0, A p = 39829 for p mod 3 = 1, A p = 39839 for p mod 3 = 2, D= 65537

[0145] - n RNTI : Terminal identifier

[0146] The value may be 0 for the common search space.

[0147] In the case of a terminal-specific search space, the value may correspond to a value that changes according to the terminal's identity (C-RNTI or ID set by the base station for the terminal) and the time index.

[0148] NR has a CSI framework for directing the measurement and reporting of channel state information (CSI) from a terminal at a base station. The CSI framework of NR can be composed of at least two elements: a resource setting and a report setting, and the report setting can have a connection relationship with the resource setting by referencing at least one ID of the resource setting.

[0149] According to one embodiment of the present disclosure, a resource setting may include information related to a reference signal (RS) for a terminal to measure channel state information. A base station may set at least one resource setting for a terminal. For example, a base station and a terminal may exchange signaling information such as that shown in Table 12 to transmit information regarding a resource setting.

[0150] -- ASN1START-- TAG-CSI-RESOURCECONFIG-STARTCSI-ResourceConfig ::= SEQUENCE {csi-ResourceConfigId CSI-ResourceConfigId,csi-RS-ResourceSetList CHOICE {nzp-CSI-RS-SSB SEQUENCE {nzp-CSI-RS-ResourceSetList SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourceSetsPerConfig)) OF NZP-CSI-RS-ResourceSetIdOPTIONAL, -- Need Rcsi-SSB-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-SSB-ResourceSetsPerConfig)) OF CSI-SSB-ResourceSetIdOPTIONAL -- Need R},csi-IM-ResourceSetList SEQUENCE (SIZE (1..maxNrofCSI-IM-ResourceSetsPerConfig)) OF CSI-IM-ResourceSetId},bwp-Id BWP-Id,resourceType ENUMERATED { aperiodic, semiPersistent, periodic},...}-- TAG-CSI-RESOURCECONFIG-STOP-- ASN1STOP

[0151] In Table 12, the signaling information CSI-ResourceConfig contains information for each resource setting. According to the signaling information, each resource setting may include a resource setting index (csi-ResourceConfigId), a BWP index (bwp-ID), a resource time-axis transmission setting (resourceType), or a resource set list (csi-RS-ResourceSetList) containing at least one resource set. The resource time-axis transmission setting may be set to aperioditic transmission, semi-persistent transmission, or periodic transmission. The resource set list may be a set containing resource sets for channel measurement or a set containing resource sets for interference measurement. If the resource set list is a set containing resource sets for channel measurement, each resource set may contain at least one resource, which may be an index of a CSI-RS resource or an SS / PBCH block. If the resource set list is a set containing resource sets for interference measurement, each resource set may include at least one interference measurement resource (CSI interference measurement, CSI-IM). For example, if the resource set includes CSI-RS, the base station and the terminal may exchange signaling information such as that shown in Table 13 to transmit information about the resource set.

[0152] -- ASN1START-- TAG-NZP-CSI-RS-RESOURCESET-STARTNZP-CSI-RS-ResourceSet ::= SEQUENCE {nzp-CSI-ResourceSetId NZP-CSI-RS-ResourceSetId,nzp-CSI-RS-Resources SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerSet)) OF NZP-CSI-RS-ResourceId,repetition ENUMERATED { on, off} OPTIONAL, -- Need SaperiodicTriggeringOffset INTEGER(0..6) OPTIONAL, -- Need Strs-Info ENUMERATED {true} OPTIONAL, -- Need R...}-- TAG-NZP-CSI-RS-RESOURCESET-STOP-- ASN1STOP

[0153] In Table 13, the signaling information NZP-CSI-RS-ResourceSet contains information about each resource set. According to the signaling information, each resource set contains at least information regarding the resource set index (nzp-CSI-ResourceSetId) or the set of indices of the included CSI-RS (nzp-CSI-RS-Resources), and may include some information regarding the spatial domain transmission filter of the included CSI-RS resource (repetition) or whether the included CSI-RS resource is used for tracking (trs-Info). CSI-RS may be the most representative reference signal included in the resource set. The base station and the terminal may exchange signaling information such as that in Table 14 to transmit information regarding the CSI-RS resource.

[0154] -- ASN1START-- TAG-NZP-CSI-RS-RESOURCE-STARTNZP-CSI-RS-Resource ::= SEQUENCE {nzp-CSI-RS-ResourceId NZP-CSI-RS-ResourceId,resourceMapping CSI-RS-ResourceMapping,powerControlOffset INTEGER (-8..15),powerControlOffsetSS ENUMERATED{db-3, db0, db3, db6} OPTIONAL, -- Need RscramblingID ScramblingId,periodicityAndOffset CSI-ResourcePeriodicityAndOffset OPTIONAL, -- Cond PeriodicOrSemiPersistentqcl-InfoPeriodicCSI-RS TCI-StateId OPTIONAL, -- Cond Periodic...}-- TAG-NZP-CSI-RS-RESOURCE-STOP-- ASN1STOP

[0155] In Table 14, the signaling information NZP-CSI-RS-Resource contains information for each CSI-RS. The information included in the above signaling information NZP-CSI-RS-Resource may have the following meanings: - nzp-CSI-RS-ResourceId: CSI-RS resource index

[0156] - resourceMapping: Resource mapping information of CSI-RS resources

[0157] - powerControlOffset: Ratio between PDSCH EPRE (Energy Per RE) and CSI-RS EPRE

[0158] - powerControlOffsetSS: Ratio between SS / PBCH block EPRE and CSI-RS EPRE

[0159] - scramblingID: Scrambling index of the CSI-RS sequence

[0160] - periodicityAndOffset: Transmission period and slot offset of the CSI-RS resource

[0161] - qcl-InfoPeriodicCSI-RS: TCI-state information if the corresponding CSI-RS is a periodic CSI-RS

[0162] The resourceMapping included in the above signaling information NZP-CSI-RS-Resource represents resource mapping information of the CSI-RS resource and may include frequency resource element (RE) mapping, number of ports, symbol mapping, CDM type, frequency resource density, and frequency band mapping information. The number of ports, frequency resource density, CDM type, and time-frequency axis RE mapping that can be configured through this may have a value set in one of the rows of Table 15 below.

[0163] [Table 15]

[0164]

[0165] Table 15 shows the frequency resource density, CDM type, frequency axis, and time axis start positions of the CSI-RS component RE pattern configurable according to the number of CSI-RS ports (X). ), represents the number of frequency axis REs (k') and the number of time axis REs (l') of the CSI-RS component RE pattern. The aforementioned CSI-RS component RE pattern may be a basic unit constituting a CSI-RS resource. Through Y=1+max(k') REs on the frequency axis and Z=1+max(l') REs on the time axis, the CSI-RS component RE pattern may be composed of YZ REs. When the number of CSI-RS ports is 1 port, the CSI-RS RE location can be specified without subcarrier restrictions within the PRB (Physical Resource Block), and the CSI-RS RE location can be specified by a 12-bit bitmap. When the number of CSI-RS ports is {2, 4, 8, 12, 16, 24, 32} and Y=2, CSI-RS RE positions can be assigned for every two subcarriers within the PRB, and CSI-RS RE positions can be assigned by a 6-bit bitmap. When the number of CSI-RS ports is 4 and Y=4, CSI-RS RE positions can be assigned for every four subcarriers within the PRB, and CSI-RS RE positions can be assigned by a 3-bit bitmap. Similarly, time axis RE positions can be assigned by a total of 14-bit bitmaps. In this case, depending on the Z value in Table 15, it is possible to change the length of the bitmap as with frequency position assignment, but since the principle is similar to the explanation above, redundant explanations will be omitted below.

[0166] According to one embodiment of the present disclosure, a report setting may have a connection relationship with a resource setting by referencing at least one ID of the resource setting, and the resource setting(s) having a connection relationship with the report setting provide setting information including information about a reference signal for measuring channel information. When the resource setting(s) having a connection relationship with the report setting are used for measuring channel information, the measured channel information may be used for channel information reporting according to a reporting method set in the report setting having a connection relationship.

[0167] According to one embodiment of the present disclosure, the report setting may include setting information related to the CSI reporting method. For example, a base station and a terminal may exchange signaling information such as that shown in Table 16 to transmit information regarding the report setting.

[0168] -- ASN1START-- TAG-CSI-REPORTCONFIG-STARTCSI-ReportConfig ::= SEQUENCE {reportConfigId CSI-ReportConfigId,carrier ServCellIndex OPTIONAL, -- Need SresourcesForChannelMeasurement CSI-ResourceConfigId,csi-IM-ResourcesForInterference CSI-ResourceConfigId OPTIONAL, -- Need Rnzp-CSI-RS-ResourcesForInterference CSI-ResourceConfigId OPTIONAL, -- Need RreportConfigType CHOICE {periodic SEQUENCE {reportSlotConfig CSI-ReportPeriodicityAndOffset,pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource},semiPersistentOnPUCCH SEQUENCE {reportSlotConfig CSI-ReportPeriodicityAndOffset,pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource},semiPersistentOnPUSCH SEQUENCE {reportSlotConfig ENUMERATED {sl5, sl10, sl20, sl40, sl80, sl160, sl320},reportSlotOffsetList SEQUENCE (SIZE (1.. maxNrofUL-Allocations)) OF INTEGER(0..32),p0alpha P0-PUSCH-AlphaSetId},aperiodic SEQUENCE {reportSlotOffsetList SEQUENCE (SIZE (1..maxNrofUL-Allocations)) OF INTEGER(0..32)}},reportQuantity CHOICE {none NULL,cri-RI-PMI-CQI NULL,cri-RI-i1 NULL,cri-RI-i1-CQI SEQUENCE {pdsch-BundleSizeForCSI ENUMERATED {n2, n4} OPTIONAL -- Need S},cri-RI-CQI NULL,cri-RSRP NULL,ssb-Index-RSRP NULL,cri-RI-LI-PMI-CQI NULL},reportFreqConfiguration SEQUENCE {cqi-FormatIndicator ENUMERATED { widebandCQI, subbandCQI} OPTIONAL, -- Need Rpmi-FormatIndicator ENUMERATED { widebandPMI, subbandPMI} OPTIONAL, -- Need Rcsi-ReportingBand CHOICE {subbands3 BIT STRING(SIZE(3)),subbands4 BIT STRING(SIZE(4)),subbands5 BIT STRING(SIZE(5)),subbands6 BIT STRING(SIZE(6)),subbands7 BIT STRING(SIZE(7)),subbands8 BIT STRING(SIZE(8)),subbands9 BIT STRING(SIZE(9)),subbands10 BIT STRING(SIZE(10)),subbands11 BIT STRING(SIZE(11)),subbands12 BIT STRING(SIZE(12)),subbands13 BIT STRING(SIZE(13)),subbands14 BIT STRING(SIZE(14)),subbands15 BIT STRING(SIZE(15)),subbands16 BIT STRING(SIZE(16)),subbands17 BIT STRING(SIZE(17)),subbands18 BIT STRING(SIZE(18)),...,subbands19-v1530 BIT STRING(SIZE(19))} OPTIONAL -- Need S} OPTIONAL, -- Need RtimeRestrictionForChannelMeasurements ENUMERATED {configured, notConfigured},timeRestrictionForInterferenceMeasurements ENUMERATED {configured, notConfigured},codebookConfig CodebookConfig OPTIONAL, -- Need Rdummy ENUMERATED {n1, n2} OPTIONAL, -- Need RgroupBasedBeamReporting CHOICE {enabled NULL,disabled SEQUENCE {nrofReportedRS ENUMERATED {n1, n2, n3, n4} OPTIONAL -- Need S}},cqi-Table ENUMERATED {table1, table2, table3, spare1} OPTIONAL, -- Need RsubbandSize ENUMERATED {value1, value2},non-PMI-PortIndication SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerConfig)) OF PortIndexFor8Ranks OPTIONAL, -- Need R...,[[semiPersistentOnPUSCH-v1530 SEQUENCE {reportSlotConfig-v1530 ENUMERATED {sl4, sl8, sl16}} OPTIONAL -- Need R]]}.

[0169] In Table 16, the signaling information CSI-ReportConfig contains information regarding each report setting. The information included in the above signaling information CSI-ReportConfig may have the following meanings: - reportConfigId: report setting index

[0170] - carrier: Serving cell index

[0171] - resourcesForChannelMeasurement: Resource setting index for channel measurement linked to report setting

[0172] - csi-IM-ResourcesForInterference: Resource setting index containing CSI-IM resources for interference measurement that have a connection with the report setting

[0173] - nzp-CSI-RS-ResourcesForInterference: Resource setting index containing CSI-RS resources for interference measurement that have a relationship with the report setting

[0174] - reportConfigType: Indicates the time-axis transmission settings and transmission channel of the channel report, and can have aperioditic transmission, semi-persistent PUCCH (Physical Uplink Control Channel) transmission, semi-persistent PUSCH transmission, or periodic transmission settings.

[0175] - reportQuantity: Indicates the type of channel information being reported, and may have the type of channel information when no channel report is transmitted ('none') or when channel report is transmitted ('cri-RI-PMI-CQI', 'cri-RI-i1', 'cri-RI-i1-CQI', 'cri-RI-CQI', 'cri-RSRP', 'ssb-Index-RSRP', 'cri-RI-LI-PMI-CQI'). Here, the elements included in the type of channel information refer to CQI (Channel Quality Indicator), PMI (Precoding Matric Indicator), CRI (CSI-RS Resource Indicator), SSBRI (SS / PBCH block Resource Indicator), Layer Indicator (LI), Rank Indicator (RI), and / or L1-RSRP (Reference Signal Received Power).

[0176] - reportFreqConfiguration: Indicates whether the reported channel information includes only wideband information or information for each subband; if information for each subband is included, it can have configuration information for the subband containing the channel information.

[0177] - timeRestrictionForChannelMeasurements: Whether there are time axis constraints on the reference signal for channel measurement among the reference signals referenced by the reported channel information.

[0178] - timeRestrictionForInterferenceMeasurements: Whether there are time axis constraints on the reference signal for interference measurement among the reference signals referenced by the reporting channel information.

[0179] - codebookConfig: Codebook information referenced by the reporting channel information

[0180] - groupBasedBeamReporting: Whether to group beams in channel reporting

[0181] - cqi-Table: CQI table index referenced by the reporting channel information

[0182] - subbandSize: An index indicating the subband size of the channel information

[0183] - non-PMI-PortIndication: Port mapping information referenced when reporting non-PMI channel information

[0184] When a base station instructs a channel information report through upper layer signaling or L1 signaling, the terminal can perform the channel information report by referring to the above-mentioned setting information included in the instructed report setting.

[0185] The base station may instruct the terminal to report channel state information through upper layer signaling, including RRC signaling or MAC (medium access control) CE (control element) signaling, or L1 signaling (e.g., common DCI, group-common DCI, terminal-specific DCI).

[0186] For example, a base station may instruct a terminal to report aperiodic channel information (CSI report) via upper layer signaling or DCI using DCI format 0_1. The base station sets parameters for the terminal's aperiodic CSI report, or a plurality of CSI report trigger states, which include parameters for the CSI report, via upper layer signaling. The parameters for the CSI report or the CSI report trigger states may include a slot interval or a set of possible slot intervals between a PDCCH containing DCI and a PUSCH containing the CSI report, a reference signal ID for measuring channel state, and the type of channel information included. When the base station instructs some of the plurality of CSI report trigger states to the terminal via DCI, the terminal reports channel information according to the CSI report settings of the report settings configured in the instructed CSI report trigger states. The channel information reporting may be performed via a PUSCH scheduled in DCI format 0_1. The time-domain resource allocation of a PUSCH containing a terminal's CSI report can be achieved through the slot interval with the PDCCH indicated via the DCI, and the indication of the starting symbol and symbol length within the slot for the time-domain resource allocation of the PUSCH. For example, the location of the slot in which the PUSCH containing the terminal's CSI report is transmitted can be indicated via the slot interval with the PDCCH indicated via the DCI, and the starting symbol and symbol length within the slot can be indicated via the time domain resource assignment field of the aforementioned DCI.

[0187] For example, a base station may instruct a terminal to send a semi-persistent CSI report via a DCI using DCI format 0_1. The base station may activate or deactivate the semi-persistent CSI report sent via a PUSCH via a DCI scrambled with SP-CSI-RNTI. When the semi-persistent CSI report is activated, the terminal may periodically report channel information according to a set slot interval. When the semi-persistent CSI report is deactivated, the terminal may stop the periodic channel information reporting that was activated. The base station establishes a number of CSI report trigger states containing parameters for the terminal's semi-persistent CSI report or parameters for the semi-persistent CSI report through upper layer signaling. Parameters for a CSI report, or CSI report trigger states, may include a set of slot intervals or possible slot intervals between a PDCCH containing a DCI directing a CSI report and a PUSCH containing a CSI report, a slot interval between a slot where an upper-layer signaling directing a CSI report is activated and a PUSCH containing a CSI report, a slot interval period of the CSI report, and the type of channel information included. When a base station activates some of a plurality of CSI report trigger states or some of a plurality of report settings to a terminal via upper-layer signaling or a DCI, the terminal may report channel information according to the report setting included in the directed CSI report trigger state or the CSI report setting configured in the activated report setting.The above channel information reporting can be performed through a PUSCH that is semi-continuously scheduled in DCI format 0_1 ​​scrambled with SP-CSI-RNTI. Time-axis resource allocation for a PUSCH containing a terminal's CSI report can be achieved through the slot interval period of the CSI report, the slot interval with the slot where upper-layer signaling is activated, the slot interval with the PDCCH indicated via DCI, and the indication of the start symbol and symbol length within the slot for time-axis resource allocation of the PUSCH. For example, the location of the slot in which the PUSCH containing the terminal's CSI report is transmitted can be indicated through the slot interval with the PDCCH indicated via DCI, and the start symbol and symbol length within the slot can be indicated through the time domain resource assignment field of the aforementioned DCI format 0_1.

[0188] For example, a base station may instruct a terminal to transmit a semi-persistent CSI report via PUCCH through upper-layer signaling such as MAC-CE. Through the MAC-CE signaling, the base station may activate or deactivate the semi-persistent CSI report transmitted via PUCCH. When the semi-persistent CSI report is activated, the terminal may periodically report channel information according to a set slot interval. When the semi-persistent CSI report is deactivated, the terminal may stop the periodic channel information reporting that was activated. The base station sets parameters for the terminal's semi-persistent CSI report through upper-layer signaling. The parameters for the CSI report may include the PUCCH resource to which the CSI report is transmitted, the slot interval period of the CSI report, and the type of channel information included. The terminal may transmit the CSI report via PUCCH. Alternatively, if the PUCCH for the CSI report overlaps with the PUSCH, the CSI report can be transmitted to the PUSCH. The location of the PUCCH transmission slot containing the CSI report is indicated by the slot interval period of the CSI report set through upper-layer signaling, and the slot interval between the slot where the upper-layer signaling is activated and the PUCCH containing the CSI report. The starting symbol and symbol length within the slot can be indicated by the starting symbol and symbol length assigned to the PUCCH resource set through upper-layer signaling.

[0189] For example, a base station may instruct a terminal to issue a periodic CSI report via upper layer signaling. The base station may enable or disable the periodic CSI report via upper layer signaling, including RRC signaling. When the periodic CSI report is enabled, the terminal may report channel information periodically according to the set slot interval. When the periodic CSI report is disabled, the terminal may stop the periodic channel information reporting that was enabled. The base station establishes a report setting containing parameters for the terminal's periodic CSI report via upper layer signaling. The parameters for the CSI report may include the PUCCH resource setting for the CSI report, the slot interval between the slot where the upper layer signaling instructing the CSI report is enabled and the PUCCH containing the CSI report, the slot interval period of the CSI report, a reference signal ID for measuring channel state, and the type of channel information included. The terminal may transmit the CSI report via the PUCCH. Alternatively, if the PUCCH for the CSI report overlaps with the PUSCH, the CSI report can be transmitted via the PUSCH. The slot location where the PUCCH containing the CSI report is transmitted is indicated by the slot interval period of the CSI report set through upper-layer signaling, and the slot interval between the slot where the upper-layer signaling is activated and the PUCCH containing the CSI report. The starting symbol and symbol length within the slot can be indicated by the starting symbol and symbol length assigned to the PUCCH resource set through upper-layer signaling.

[0190] When a base station instructs a terminal to perform a non-periodic CSI report or a semi-continuous CSI report via DCI, the terminal can determine whether it can perform a valid channel report through the instructed CSI report by considering the channel computation time required for the CSI report. For the non-periodic CSI report or semi-continuous CSI report instructed via DCI, the terminal can perform a valid CSI report starting from the uplink symbol after the Z symbol, after the last symbol included in the PDCCH containing the DCI instructing the CSI report has ended. The aforementioned Z symbol may vary depending on the numerology of the downlink bandwidth part corresponding to the PDCCH containing the DCI instructing the CSI report, the numerology of the uplink bandwidth part corresponding to the PUSCH transmitting the CSI report, and the type or characteristics of the CSI reported in the CSI report (report quantity, frequency band granularity, number of ports of the reference signal, codebook type, etc.). In other words, for a CSI report to be determined as a valid CSI report, the uplink transmission of the said CSI report must include TA (timing advance) and Z ref It must not be executed before the symbol. In this case, Z ref The symbol is time from the moment the last symbol of the above-mentioned triggering PDCCH ends. It is an uplink symbol that initiates the CP (cyclic prefix). Here, the detailed value of Z follows the explanation below, , , N f =4096, κ=64, and μ is the numerology. Here, μ is (μ PDCCH , μ CSI-RS , μ UL The largest T among ) proc,CSI It can be promised to use what causes the value, and μ PDCCHμ is the subcarrier spacing used for PDCCH transmission. CSI-RS μ is the subcarrier spacing used for CSI-RS transmission. UL can refer to the subcarrier spacing of the uplink channel used for transmitting UCI (uplink control information) for CSI reporting. As another example, μ is (μ PDCCH , μ UL The largest T among ) proc,CSI It is also possible to promise to use what causes the value μ PDCCH and μ UL Refer to the explanation above for the definition of. For convenience of future explanation, satisfying the above conditions will be referred to as satisfying CSI Report Validity Condition 1.

[0191] In addition, if the reference signal for channel measurement regarding the aperiodic CSI report instructed to the terminal via the DCI is an aperiodic reference signal, a valid CSI report can be performed starting from the uplink symbol following the Z' symbol after the end of the last symbol containing the reference signal; the aforementioned Z' symbol may vary depending on the numerology of the downlink bandwidth part corresponding to the PDCCH containing the DCI instructing the CSI report, the numerology of the bandwidth corresponding to the reference signal for channel measurement regarding the CSI report, the numerology of the uplink bandwidth part corresponding to the PUSCH transmitting the CSI report, and the type or characteristics of the CSI reported in the CSI report (report quantity, frequency band granularity, number of ports of the reference signal, codebook type, etc.). In other words, for a certain CSI report to be determined as a valid CSI report, the uplink transmission of the said CSI report must include TA and Z ref' It must not be executed before the symbol. In this case, Z ref' The symbol is time from the moment the last symbol of the non-periodic CSI-RS or non-periodic CSI-IM triggered by the above-mentioned triggering PDCCH ends. This is the uplink symbol that starts the CP. Here, the detailed value of Z' follows the explanation below, , , N f =4096, κ=64, and μ is the numerology. Here, μ is (μ PDCCH , μ CSI-RS , μ UL The largest T among ) proc,CSI It can be promised to use what causes the value, and μ PDCCH μ is the subcarrier interval used for triggering PDCCH transmission. CSI-RS μ is the subcarrier spacing used for CSI-RS transmission. UL may refer to the subcarrier spacing of the uplink channel used for UCI transmission for CSI reporting. As another example, μ is (μ PDCCH , μ UL The largest T among ) proc,CSI It can be promised to use what causes the value. In this case, μ PDCCH and μ UL Refer to the explanation above for the definition of. For convenience of future explanation, satisfying the above conditions will be referred to as satisfying CSI Report Validity Condition 2.

[0192] If a base station instructs a terminal to report a non-periodic CSI for a non-periodic reference signal via DCI, the terminal may perform a valid CSI report starting from the first uplink symbol that satisfies both the time point Z after the end of the last symbol included in the PDCCH containing the DCI instructing the CSI report and the time point Z' after the end of the last symbol containing the reference signal. That is, in the case of a non-periodic CSI report based on a non-periodic reference signal, it is determined to be a valid CSI report only if it satisfies both CSI report validity conditions 1 and 2.

[0193] If the CSI reporting time specified by the base station does not satisfy the CSI calculation time requirements, the terminal may determine that the CSI report is invalid and not consider a CSI status update for the CSI report.

[0194] The Z and Z' symbols for calculating the CSI calculation time described above follow Tables 17 and 18 below. For example, if the CSI reported in the CSI report contains only broadband information, the number of reference signal ports is 4 or less, the reference signal resource is one, the codebook type is 'typeI-SinglePanel', or the type of the reported CSI (report quantity) is 'cri-RI-CQI', the Z and Z' symbols follow the Z1 and Z1' values ​​in Table 18. This will be referred to as delay requirement 2. In addition, if the PUSCH containing the CSI report does not include a transmission block or HARQ-ACK (hybrid automatic repeat request acknowledgment) and the terminal's CSI processing unit (CSI processing unit, CPU) occupation is 0, the Z and Z' symbols follow the Z1 and Z1' values ​​in Table 17 and this will be referred to as delay requirement 1. The explanation regarding the aforementioned CPU occupancy is described in detail below. Additionally, when the reportquantity is 'cri-RSRP' or 'ssb-Index-RSRP', the Z and Z' symbols follow the Z3 and Z3' values ​​in Table 18. X1, X2, X3, and X4 in Table 18 represent the terminal's capability (UE capability) regarding beam reporting time, and KB1 and KB2 in Table 18 represent the terminal's capability regarding beam switching time. If the type or characteristic of the CSI reported in the aforementioned CSI report does not apply, the Z and Z' symbols follow the Z2 and Z2' values ​​in Table 18.

[0195] μZ1[symbols]Z1Z'10108113112252134336

[0196] μZ1[symbols]Z2[symbols]Z3[symbols]Z1Z'1Z2Z'2Z3Z'302216403722X113330726933X224442141140min(44, X3+KB1)X339785152140min(97, X4+KB2)X4

[0197] When a base station instructs a terminal to perform non-periodic, semi-continuous, or periodic CSI reporting, it may set a CSI reference resource to determine the reference time and frequency for the channel to be reported in the CSI report. The frequency of the CSI reference resource may be the carrier and subband information to be measured for the CSI, as specified in the CSI report configuration, and may correspond, respectively, to the carrier and reportFreqConfiguration within the higher-layer signaling, CSI-ReportConfig. The time of the CSI reference resource may be defined based on the time at which the CSI report is transmitted. For example, if CSI report #X is instructed to be transmitted in the uplink slot n' of the carrier and BWP to be transmitted, the time of the CSI reference resource for CSI report #X is the downlink slot nn of the carrier and BWP measuring the CSI. CSI-ref It can be defined as. The downlink slot n represents the numerology of the carrier and BWP measuring CSI μ DL , CSI report #X transmitting carrier and BWP numerology μ UL When named as It is calculated as. n, the slot interval between the downlink slot n and the CSI reference signal slot n. CSI-ref If CSI report #X transmitted in uplink slot n' is a semi-continuous or periodic CSI report, depending on the number of CSI-RS / SSB resources for channel measurements, if a single CSI-RS / SSB resource is connected to the said CSI report If it follows and multiple CSI-RS / SSB resources are linked to the relevant CSI report Follows. If the CSI report #X transmitted in uplink slot n' is a non-periodic CSI report, considering the CSI calculation time Z' for channel measurement It is calculated as. The aforementioned is the number of symbols included in one slot, and in NR, it is assumed to be 14.

[0198] When a base station instructs a terminal to transmit a CSI report in uplink slot n' via upper layer signaling or DCI, the terminal may report a CSI by performing channel measurement or interference measurement on a CSI-RS resource, CSI-IM resource, or SSB resource associated with the CSI report that is transmitted no later than the CSI reference resource slot of the CSI report transmitted in uplink slot n'. The CSI-RS resource, CSI-IM resource, or SSB resource associated with the above-mentioned CSI report may refer to a CSI-RS resource, CSI-IM resource, or SSB resource included in a resource set configured in a resource setting referenced by a report setting for a CSI report of a terminal configured through upper layer signaling, or a CSI-RS resource, CSI-IM resource, or SSB resource referenced by a CSI report trigger state containing parameters for the CSI report, or a CSI-RS resource, CSI-IM resource, or SSB resource pointed to by an ID of a reference signal (RS) set.

[0199] In embodiments of the present disclosure, the CSI-RS / CSI-IM / SSB occasion refers to the transmission time of the CSI-RS / CSI-IM / SSB resource(s) determined by the upper layer setting or a combination of the upper layer setting and DCI triggering. For example, for a semi-persistent or periodic CSI-RS resource, the slot to be transmitted is determined according to the slot period and slot offset set by the upper layer signaling, and the slot-transmitted symbol(s) are determined by referring to one of the slot-transmitted resource mapping methods of Table 16 according to the resource mapping information. For another example, for an aperiodic CSI-RS resource, the slot to be transmitted is determined according to the slot offset with the PDCCH containing the DCI indicating channel reporting set by the upper layer signaling, and the slot-transmitted symbol(s) are determined by referring to one of the slot-transmitted resource mapping methods of Table 16 according to the resource mapping information.

[0200] The aforementioned CSI-RS occasion can be determined by independently considering the transmission time of each CSI-RS resource or by comprehensively considering the transmission time of one or more CSI-RS resource(s) included in the resource set; accordingly, the following two interpretations are possible for the CSI-RS occasion according to each resource set setting.

[0201] - Interpretation 1-1: From the start time of the earliest symbol to the end time of the latest symbol during which a specific resource among one or more CSI-RS resources included in the resource set(s) configured in the resource setting referenced by the report setting configured for the CSI report is transmitted.

[0202] - Interpretation 1-2: Among all CSI-RS resources included in the resource set(s) configured in the resource setting referenced by the report setting configured for the CSI report, from the start time of the earliest symbol transmitted by the earliest transmitted CSI-RS resource to the end time of the latest symbol transmitted by the latest transmitted CSI-RS resource

[0203] In the embodiments of the present disclosure below, it is possible to individually apply both interpretations of the CSI-RS occasion. Additionally, while it is possible to consider both interpretations for the CSI-IM occasion and the SSB occasion, just as with the CSI-RS occasion, the principle is similar to the explanation above, so redundant explanations will be omitted below.

[0204] In embodiments of the present disclosure, 'CSI-RS / CSI-IM / SSB occasion for CSI report #X transmitted in uplink slot n'' refers to a set of CSI-RS occasions, CSI-IM occasions, and SSB occasions among the CSI-RS resource, CSI-IM resource, and SSB resource CSI-RS occasions, CSI-IM occasions, and SSB occasions included in the resource set of the resource setting referenced by the report setting set for CSI report #X, which are not later than the CSI reference resource of CSI report #X transmitted in uplink slot n'.

[0205] In the embodiments of the present disclosure, the latest CSI-RS / CSI-IM / SSB occasion among the CSI-RS / CSI-IM / SSB occasions for CSI report #X transmitted in 'uplink slot n' can be interpreted in the following two ways.

[0206] - Interpretation 2-1: A set of occasions including the latest CSI-RS occasion for CSI report #X transmitted in uplink slot n', the latest CSI-IM occasion for CSI report #X transmitted in uplink slot n', and the latest SSB occasion for CSI report #0 transmitted in uplink slot n'.

[0207] - Interpretation 2-2: The latest occasion among the CSI-RS occasion, CSI-IM occasion, and SSB occasion for CSI report #X transmitted in uplink slot n'.

[0208] In the embodiments of the present disclosure below, it is possible to apply individually by considering both interpretations of the ‘latest CSI-RS / CSI-IM / SSB occasion among the CSI-RS / CSI-IM / SSB occasions for CSI report #X transmitted in uplink slot n’. Additionally, when considering the two interpretations (interpretation 1-1, interpretation 1-2) described above for the CSI-RS occasion, CSI-IM occasion, and SSB occasion, in the embodiments of the present disclosure, the “latest CSI-RS / CSI-IM / SSB occasion among the CSI-RS / CSI-IM / SSB occasions for CSI report #X transmitted in uplink slot n’” can be applied individually by considering all four different interpretations (applying interpretation 1-1 and interpretation 2-1, applying interpretation 1-1 and interpretation 2-2, applying interpretation 1-2 and interpretation 2-1, applying interpretation 1-2 and interpretation 2-2).

[0209] The base station may instruct a CSI report by considering the amount of CSI that the terminal can simultaneously calculate for the CSI report, that is, the number of the terminal's CSI processing units (CPUs). The number of CSI processing units that the terminal can simultaneously calculate is N CPU If so, the terminal is N CPU Do not expect CSI report instructions from base stations requiring more CSI calculations, or N CPU Updates to the CSI that require more CSI calculations may not be considered. N CPU The terminal can report to the base station via upper layer signaling, or the base station can set it via upper layer signaling.

[0210] The CSI report instructed by the base station to the terminal is the total number of CSIs N that the terminal can calculate simultaneously. CPU Assume that some or all of the CPUs are occupied for CSI calculations. For each CSI report, for example, the number of CSI calculation units required for CSI report n (n=0, 1, ... N-1) If so, the number of CSI calculation units required for a total of N CSI reports is It can be said that. The CSI calculation units required for each reportQuantity set in the CSI report can be set as follows.

[0211] - : When the reportQuantity set in the CSI report is set to 'none', and trs-Info is set in the CSI-RS resource set connected to the CSI report- : If the reportQuantity set in the CSI report is set to 'none', 'cri-RSRP', or 'ssb-Index-RSRP', and trs-Info is not set in the CSI-RS resource set associated with the CSI report - If the reportQuantity set in the CSI report is set to 'cri-RI-PMI-CQI', 'cri-RI-i1', 'cri-RI-i1-CQI', 'cri-RI-CQI', or 'cri-RI-LI-PMI-CQI' >> : When a non-periodic CSI report is triggered and the said CSI report is not multiplexed with one or both of TB / HARQ-ACK. The said CSI report is a wideband CSI corresponding to a maximum of 4 CSI-RS ports, corresponds to a single resource without a CRI report, and corresponds to codebookType 'typeI-SinglePanel' or reportQuantity 'cri-RI-CQI' (this case corresponds to the aforementioned delay requirement 1, which can be viewed as a situation where the terminal uses all available CPUs to quickly calculate and report the CSI) : All other cases except the above case. K s indicates the number of CSI-RS resources within the CSI-RS resource set for channel measurement.

[0212] If, at a specific point in time, the number of channel information calculations required by the terminal for multiple CSI reports exceeds the number of channel information calculation units (NCPUs) that the terminal can simultaneously process, the terminal may not consider updating channel information for some CSI reports. Among multiple directed CSI reports, the CSI reports for which channel information updates are not considered are determined by taking into account at least the time the channel information calculations required for the CSI report occupy the CPU and the priority of the reported channel information. For example, it is possible to not consider updating channel information for a CSI report where the time the channel information calculations required for the CSI report start occupying the CPU is the latest, and to prioritize not considering channel information updates for CSI reports with lower channel information priority.

[0213] The priority of the above channel information can be determined by referring to Table 20 below.

[0214] CSI priority value - y=0 if it is an aperiodic CSI report transmitted via PUSCH, y=1 if it is a semi-persistent CSI report transmitted via PUSCH, y=2 if it is a semi-persistent CSI report transmitted via PUCCH, y=3 if it is a periodic CSI report transmitted via PUCCH; - k=0 if the CSI report contains L1-RSRP, k=1 if the CSI report does not contain L1-RSRP; - c: serving cell index, Ncells: maximum number of serving cells configured for upper-tier signaling (maxNrofServingCells); - s: CSI report configuration index (reportConfigID), Ms: maximum number of CSI report configurations configured for upper-tier signaling (maxNrofCSI-ReportConfigurations).

[0215] The CSI priority for the CSI report is the priority value Pri in Table 20. iCSI It is determined through (y,k,c,s). Referring to Table 20, the CSI priority value is determined by the type of channel information included in the CSI report, the temporal reporting characteristics of the CSI report (aperiodic, semi-persistent, periodic), the channel through which the CSI report is transmitted (PUSCH, PUCCH), the serving cell index, and the CSI report configuration index. The CSI priority for a CSI report is the priority value Pri iCSI By comparing (y,k,c,s), it is determined that the CSI report with the smaller priority value has a higher CSI priority.

[0216] If CPU occupation time is defined as the time the CPU is occupied by calculating channel information required for the CSI report instructed by the base station to the terminal, then CPU occupation time is determined by considering the type of channel information included in the CSI report (report quantity), the time-axis characteristics of the CSI report (aperiodic, semi-persistent, periodic), the slots or symbols occupied by the upper-layer signaling or DCI instructing the CSI report, and part or all of the slots or symbols occupied by the reference signal for channel state measurement.

[0217] Regarding the aforementioned CSI report settings (CSI-ReportConfig), each report setting CSI-ReportConfig can be associated with a single downlink (DL) bandwidth portion identified by the upper-layer parameter bandwidth portion identifier (bwp-id) given by the CSI-ResourceConfig, which is associated with the corresponding report setting. As for the time domain reporting operation for each report setting CSI-ReportConfig, 'Aperiodic', 'Semi-Persistent', and 'Periodic' methods are supported, and these can be configured from the base station to the terminal by the reportConfigType parameter set from the upper layer. The semi-persistent CSI reporting methods support 'PUCCH-based semi-persistent (semi-PersistentOnPUCCH)' and 'PUSCH-based semi-persistent (semi-PersistentOnPUSCH)'. In the case of a periodic or semi-permanent CSI reporting method, the terminal may receive a PUCCH or PUSCH resource to transmit the CSI from the base station via upper layer signaling. The period and slot offset of the PUCCH or PUSCH resource to transmit the CSI may be given as the numerology of the uplink (UL) bandwidth portion configured for transmitting the CSI report. In the case of a non-periodic CSI reporting method, the terminal may receive a PUSCH resource to transmit the CSI scheduled from the base station via L1 signaling (the aforementioned DCI format 0_1).

[0218] 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.

[0219] - CSI-IM resources for interference measurement

[0220] - NZP CSI-RS resources for interference measurement

[0221] - NZP CSI-RS resources for channel measurement

[0222] 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.

[0223] 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 21 below.

[0224] CSI-RS ConfigurationPeriodic CSI ReportingSemi-Persistent CSI ReportingAperiodic CSI ReportingPeriodic CSI-RSNo dynamic triggering / activationFor reporting on PUCCH, the UE receives an activation command [10, TS 38.321]; for reporting on PUSCH, the UE receives triggering on DCITriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.Semi-Persistent CSI-RSNot SupportedFor reporting on PUCCH, the UE receives an activation command [10, TS 38.321]; for reporting on PUSCH, the UE receives triggering on DCITriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.Aperiodic CSI-RSNot SupportedNot SupportedTriggered by DCI; additionally, activation command [10, TS 38.321] possible as defined in Subclause 5.2.1.5.1.

[0225] Aperiodic 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 can be set to NTS (=0, 1, 2, 3, 4, 5, or 6) bits and can be determined by the upper layer signaling (reportTriggerSize). One trigger state among one or more aperiodic CSI reporting trigger states that can be set by the upper layer signaling (CSI-AperiodicTriggerStateList) can be triggered by the CSI request indicator.

[0226] - If all bits of the CSI request field are 0, this may mean that a CSI report is not requested.

[0227] - 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.

[0228] - 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.

[0229] Table 22 below shows an example of the relationship between CSI request indicators and CSI trigger states that can be indicated by those indicators.

[0230] CSI request fieldCSI trigger stateCSI-ReportConfigIdCSI-ResourceConfigId00no CSI requestN / AN / A01CSI trigger state#1CSI report#1CSI resource#1,CSI report#2CSI resource#210CSI trigger state#2CSI report#3CSI resource#311CSI trigger state#3CSI report#4CSI resource#4

[0231] 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 uplink data (UL-SCH) and the acquired CSI can be multiplexed and transmitted to the PUSCH resource scheduled by DCI format 0_1. If the 1 bit corresponding to the uplink data indicator (UL-SCH indicator) in DCI format 0_1 ​​indicates "0", CSI can be mapped and transmitted without uplink data (UL-SCH) to the PUSCH resource scheduled by DCI format 0_1.

[0232] Figure 6 is a diagram illustrating an example of a non-periodic CSI reporting method.

[0233] In the example (600) of FIG. 6, the terminal can monitor the PDCCH (601) to obtain the DCI format 0_1, from which it can obtain scheduling information and CSI request information for the PUSCH (605). The terminal can obtain resource information for the CSI-RS (602) to be measured from the received CSI request indicator. The terminal can determine at what point in time it should perform a measurement on the CSI-RS (602) resource being transmitted based on the time it receives DCI format 0_1 ​​and the parameter for the offset within the CSI resource set setting (e.g., NZP CSI-RS resource set setting (NZP-CSI-RS-ResourceSet) (the aperiodicTriggeringOffset described above). 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 non-periodic 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 23 below.

[0234] aperiodicTriggeringOffsetOffset X00 slot11 slot22 slots33 slots44 slots516 slots624 slots

[0235] In one example (600) of FIG. 6, an example is shown in which the aforementioned offset value is set to X=0. In this case, the terminal can receive CSI-RS (602) in a slot (corresponding to slot 0 (606) in FIG. 6) that receives DCI format 0_1 ​​that triggers a non-periodic CSI report, and can report the CSI information measured by the received CSI-RS to the base station via PUSCH (605). The terminal can obtain scheduling information for PUSCH (605) for CSI reporting (information corresponding to each field of the aforementioned DCI format 0_1) from DCI format 0_1. For example, the terminal can obtain information about the slot to transmit PUSCH (605) from the aforementioned time domain resource allocation information for PUSCH (605) in DCI format 0_1. In example (600) of FIG. 6, the terminal obtains a K2 value corresponding to the slot offset value for PDCCH-to-PUSCH as 3, and accordingly, PUSCH (605) can be transmitted from slot 3 (609), which is 3 slots away from slot 0 (606), at the time when PDCCH (601) is received. In example (610) of FIG. 6, the terminal can monitor PDCCH (611) to obtain DCI format 0_1, from which scheduling information and CSI request information for PUSCH (615) can be obtained. The terminal can obtain resource information for CSI-RS (612) to be measured from the received CSI request indicator. Example (610) of FIG. 6 shows an example in which the offset value for the aforementioned CSI-RS is set to X=1. In this case, the terminal can receive CSI-RS (612) in the slot that receives DCI format 0_1 ​​that triggers a non-periodic CSI report (corresponding to slot 0 (616) in FIG. 6), and can report the CSI information measured by the received CSI-RS to the base station via PUSCH (615).

[0236] A non-periodic CSI report may include at least one or both of CSI part 1 or CSI part 2, and when the non-periodic CSI report is transmitted via PUSCH, it may be multiplexed with a transport block. For multiplexing, a CRC may be inserted into the input bits of the non-periodic CSI, followed by encoding and rate matching, and then mapped to a specific pattern in a resource element within PUSCH and transmitted. The above CRC insertion may be omitted depending on the coding method or the length of the input bits. The number of modulation symbols calculated for rate matching during the multiplexing of CSI part 1 or CSI part 2 included in the non-periodic CSI report can be calculated as follows.

[0237]

[0238]

[0239] In particular, for PUSCH repetition transmission methods A and B, the terminal can transmit aperiodic CSI reports by multiplexing them only during the first repetition of the PUSCH repetition. This is because the aperiodic CSI report information being multiplexed is encoded in a polar code format, and for it to be multiplexed across multiple PUSCH repetitions, each PUSCH repetition must have the same frequency and time resource allocation. Specifically, in the case of PUSCH repetition type B, since each actual repetition can have a different OFDM symbol length, the aperiodic CSI reports can be multiplexed and transmitted only during the first PUSCH repetition.

[0240] Additionally, regarding PUSCH repeat transmission method B, if a terminal receives a DCI that schedules a non-periodic CSI report or enables a semi-permanent CSI report without scheduling for a transport block, the value of the nominal repetition may be assumed to be 1 even if the number of PUSCH repeat transmissions set by the upper layer signaling is greater than 1. Additionally, if a terminal schedules or enables a non-periodic or semi-permanent CSI report without scheduling for a transport block based on PUSCH repeat transmission method B, the terminal may expect the first nominal repetition to be the same as the first actual repetition. For a PUSCH transmitted including a semi-permanent CSI based on PUSCH repeat transmission method B without scheduling for a DCI after semi-permanent CSI reporting is enabled by a DCI, if the first nominal repetition is different from the first actual repetition, the transmission for the first nominal repetition may be ignored.

[0241] In the future, when services are provided in high frequency bands, CSI-RS for acquiring channel state information may be configured up to, for example, 256 ports. In this case, since CSI-RS overhead increases to support a large number of antenna ports, a method and apparatus are required to reduce the number of CSI-RS antenna ports. The present disclosure proposes a method and apparatus to reduce CSI-RS overhead by reducing the number of antenna ports of transmitted CSI-RS (for example, a base station transmits 128 ports of CSI-RS) and to estimate the state of the entire channel based on a small number of CSI-RS.

[0242] The CSI-RS overhead reduction method proposed in this disclosure is described below through specific embodiments. The first to third embodiments described below may be implemented separately and / or at least some of them may be implemented in combination.

[0243] <1st Example>

[0244] FIG. 7 is a diagram illustrating an example of the concept of AI-based CSI-RS compression to reduce CSI-RS overhead applied to various embodiments of the present disclosure.

[0245] Referring to FIG. 7, the base station (721) configures the compressed CSI-RS (712) through a CSI-RS port compression (701) procedure when transmitting CSI-RS (711) for all antenna ports. The CSI-RS port compression (701) may be a port sampling procedure that selects only some CSI-RS ports from all CSI-RS ports. For example, the base station selects some M ( <N)개의 CSI-RS 포트만을 사용해 M 개의 CSI-RS를 전송할 수 있다. 또한 CSI-RS 포트 압축 (701)은 전체 CSI-RS 포트에 대해 포트 결합(port combining)을 수행하는 절차일 수 있다. 예를 들어, 전체 N개의 CSI-RS 포트에 대해 일정 k개의 포트가 1개의 CSI-RS 포트로 포트 결합된다면 기지국은 N / k 개의 CSI-RS를 전송할 수 있다. 상기 포트 샘플링에서 선택되는 포트 및 포트 결합에서 결합되는 포트는 인공지능(artificial intelligence, AI)에 기반하여 수행되는 절차일 수 있다. 기지국은 상기 CSI-RS 포트 압축 (701)에 기반하여 압축된 CSI-RS (712)를 채널 (713)을 통해 단말 (722)로 전송한다.

[0246] A terminal (722) can receive compressed CSI-RS from a base station (721) and obtain a compressed CSI-RS measurement (714). Based on the compressed CSI-RS measurement (714), the terminal estimates the channel corresponding to the compressed CSI-RS port (702). Through the estimation, the terminal can obtain a compressed CSI-RS port channel (715) corresponding to the compressed CSI-RS port. Based on the obtained compressed CSI-RS port channel (715), the terminal can restore the entire CSI-RS port channel (716) (703). This is a concept applicable to various embodiments of the present disclosure.

[0247] An AI model may be utilized in the procedure (703) for restoring the entire CSI-RS port channel from the compressed CSI-RS port channel. The terminal generates channel state information (CSI) for the restored entire CSI-RS port channel (716) (704). The channel state information may include at least one precoding matrix indicator (PMI), channel quality indicator (CQI), and rank indicator (RI) for the entire CSI-RS port channel, and the channel state information is not limited to this example, and information indicating the restored entire CSI-RS port channel (716) may correspond to the channel state information. The terminal may feed back the generated channel state information to the base station (717).

[0248] This process can also be expressed by the following formula. The terminal is a compressed CSI-RS port channel From the entire CSI-RS port channel It estimates. At this time, the compressed CSI-RS port channel and the entire CSI-RS port channel are It has a relationship like, is a function that restores the channel, and corresponds to the virtualization matrix. N p is the number of transmitting antenna ports, N r is the number of antennas at the receiving end, N t corresponds to the number of antennas at the transmitting end. In other words, the terminal through the AI ​​model It can be derived. In addition, the CSI-RS compression of the base station can be based on the virtualization matrix V mentioned above.

[0249] The Transformer can be used as an example of a channel restoration AI model. The Transformer can learn the correlation between input sequences by utilizing an attention mechanism on the input sequences. Specifically, during the training process for channel restoration, compressed channels are used as input and passed through an attention layer for the attention mechanism. In each attention layer, an inner product operation is performed between the input sequences, and based on the result of this operation (also known as the attention score), the spatial correlation between the channels can be obtained through updates to the input sequences. For example, at a specific b-th attention layer, the attention score S for input Z b The operation is S b = It is possible through. In the above equation, Q b =ZW Q b is Z and weight matrix W Q b It is a query generated by the product of K b =ZW K b is Z and weight matrix W K bIt is a key generated by the product of . The spatial correlation between ports obtained through the above attention mechanism can be utilized in the channel restoration inference process. Specifically, in the channel restoration inference process, the compressed channel is passed through a transformer as input. As the compressed channel input passes through a layer inside the transformer that has learned the spatial correlation between ports, the channels for all ports can finally be restored.

[0250] FIGS. 8a and 8b illustrate an example of port transformation according to an embodiment of the present disclosure. Port transformation may include port sampling, which selects some CSI-RS ports from a total of CSI-RS ports. In addition, it may include a procedure for compressing all CSI-RS ports through port combining.

[0251] In Fig. 8b, the port transformation index is an index representing the port transformation matrix according to the compression ratio for N CSI-RS ports. Different port transformation matrices can be defined between the base station and the terminal according to the port transformation index. The port transformation matrix can express the relationship between the entire CSI-RS port channel and the compressed CSI-RS port channel.

[0252] Port switching matrix ( ) is a matrix that converts N CSI-RS ports into M ports, and the value of M=rN can be determined according to the compression ratio r. M CSI-RS signals can be transmitted through the above-mentioned compressed M=rN CSI-RS ports. Specifically, N CSI-RS port channels are vectors of dimension N. It can be expressed as, and the port switching matrix M CSI-RS port channels by It can be compressed as follows. For example, for a total of N=128 CSI-RS ports, when the compression ratio is r=1 / 2, the base station can transmit CSI-RS using M=64 ports. A non-zero element α in the port switching matrix i is a coefficient used for CSI-RS port compression and can represent the power for the i-th CSI-RS port. α having a non-zero value i If all values ​​for are the same, the CSI-RS ports can be compressed with the same power. In addition, depending on AI model performance and the cell or wireless communication environment, the power per port is α i It can be adjusted.

[0253] If the port switching matrix based on the port switching index is not specified in the standard, it can also be identified using a bitmap in which the positions corresponding to non-zero elements in the port switching matrix are marked as 1. Port-specific coefficients can be identified using quantized values. For example, the quantized value can be one of {1, 1 / 2, 1 / 4}. The above bitmap-based port switching matrix identification can be used when a base station or cell performs CSI-RS port compression based on port switching operated independently.

[0254] Referring to FIG. 8a, port sampling or port combining can be performed according to the port switching matrix within the port switching index. 800 is an example of a CSI-RS port compressed using port sampling when port switching index 1 of FIG. 8b is applied, and 810 is an example of a CSI-RS port compressed using port sampling when port switching index 2 of FIG. 8b is applied. 820 is an example of a CSI-RS port compressed using port combining when port switching index 3 of FIG. 8b is applied, and 830 is an example of a CSI-RS port compressed using port combining when port switching index 4 of FIG. 8b is applied. For example, port switching index 1 represents a port switching matrix that selects the odd-numbered CSI-RS port for a 1 / 2 compression ratio. Additionally, port switching index 3 represents a port switching matrix that directs the combining of two adjacent CSI-RS ports when the compression ratio is 1 / 2. The port switching matrix disclosed in FIG. 8 is an example and can be modified and used according to the understanding of those skilled in the art.

[0255] FIG. 9 is a diagram illustrating an example of an AI model training process and an AI model inference process in an AI model applied to various embodiments of the present disclosure. The process can be performed at a terminal.

[0256] Referring to FIG. 9, the AI ​​model training process (960) may consist of port transformation (910), an AI model (920), and loss function / gradient calculation (930). In the AI ​​model training process, the input is the entire N CSI-RS port channel (901), and port transformation (910) is performed based on a port transformation matrix according to a set port transformation index. Port sampling or port combining may be performed according to the set port transformation index in the port transformation. The M CSI-RS port channel (902) compressed through port transformation can be used as the input to the AI ​​model (920). The AI ​​model (920) may be one of the deep neural network structures. For example, a convolutional neural network (CNN), long-short term memory (LSTM), a transformer, etc., may be used as the AI ​​model. The N CSI-RS port channel (903) restored using the AI ​​model (920) is the output of the AI ​​model and can be used as the input to the loss function / gradient calculation (930) for weight updates of the AI ​​model. In the loss function / gradient calculation (930) step, the difference between the N CSI-RS port channel (901), which is the input of the port switch (910), and the restored N CSI-RS port channel (903) is calculated as the loss function using the ground truth. For example, if the mean squared error (MSE) is set as the loss function, the MSE between the ground truth N CSI-RS port channel and the restored N CSI-RS port channel can be calculated. Based on the above-calculated loss function, the terminal performs weight updates of the AI ​​model by calculating the gradient (904) for the deep neural network weights and feeding it back to the AI ​​model.

[0257] Referring to FIG. 9, the AI ​​model inference process (970) may be composed of a trained AI model (940). The trained AI model (940) obtained through the AI ​​model training process (960) can perform one-sided AI model inference for CSI-RS port compression at the terminal. The terminal outputs N CSI-RS port channels (923) that are finally restored, using the channels (922) estimated from M compressed CSI-RS from the base station of the trained AI model (940) as input. The trained AI model may be trained on a port switching matrix corresponding to at least one port switching index. In addition, if the computational power of the AI ​​model is high, it may be trained on multiple port switching matrices. The one or more port switching matrices may be predetermined, set by the base station, or set cell-specifically.

[0258] The AI ​​model (920) is not limited to the AI ​​model described above and may refer to an entity capable of outputting an N CSI-RS port channel with an estimated channel from an M CSI-RS port as input, assuming that a specific port switching matrix is ​​applied.

[0259] FIG. 10 is a diagram illustrating an example of an AI-based CSI-RS compression transmission and reception process according to one embodiment of the present disclosure.

[0260] Referring to FIG. 10, a terminal (1001) reports port transformation information supported by a base station (1002). The terminal may report at least one supported port transformation index among specified port transformation indices (1010). A specified port transformation index corresponds to an index indicating a predetermined port transformation matrix. Additionally, if the terminal supports multiple port transformation matrices, it may report multiple port transformation indices. The terminal may report supported port transformation indices by considering the time complexity, computational complexity, and space complexity required during the AI ​​model inference process. For example, if the terminal supports port transformation index 0 and port transformation index 1, and the AI ​​model inference latency for port transformation index 0 is greater than the latency for port transformation index 1, the terminal may report only port transformation index 1 to reduce the latency.

[0261] For example, a terminal (1001) can transmit information about a supported port switching index using a capability report that can transmit capability information to a base station (1002). The capability information may additionally include capability information indicating that CSI-RS port compression is possible. For example, the terminal can indicate a supported port switching index in the form of a bitmap among the specified port switching indices. For example, when the terminal supports the first and third port switching indices among a total of five port switching indices, the terminal can report '10100'.

[0262] The base station may direct a port switching index for AI model inference based on a supported port switching index reported by the terminal (1020). The CSI-RS compression information (or port switching setting information) transmitted by the base station may be information directing a port switching index corresponding to the port switching on which the terminal will perform AI model inference among a plurality of port switching indices. The port switching index may correspond to a port sampling or port combining method. For example, the port switching setting information may be transmitted to the terminal in the form of downlink control information or MAC-CE. Depending on whether time-domain diversity or frequency-domain diversity is used, the base station may include at least one of information on frequency domain resources to which a plurality of port switching indices or port switching indices (or matrices) will be applied, or information on time domain resources to which a port switching index (or matrix) will be applied, in the port switching setting information. For example, the base station may direct a port switching index for AI model inference in the form of a bitmap for the port switching index to be directed among the specified port switching indices.

[0263] A base station (1002) can transmit CSI-RS compressed into a port switching matrix of a port switching index indicated to a terminal (1001) (1030). The base station can compress CSI-RS based on CSI-RS configuration information and port switching configuration information and transmit it to the terminal. The terminal receives the compressed CSI-RS and checks the compressed CSI-RS port channels. The terminal can restore channels corresponding to all CSI-RS ports based on the CSI-RS port channels compressed into a port switching matrix corresponding to the indicated port switching index (1040). The compressed CSI-RS port channels and all CSI-RS port channels may be spatial domain channels, or spatial-frequency domain channels, spatial-frequency-time domain channels. For example, if the compression ratio is 1 / 4 for all 256 CSI-RS ports, the terminal can restore 256 CSI-RS port channels based on 64 compressed CSI-RS port channels. When restoring compressed CSI-RS channels, an AI model inference process (970) trained according to Fig. 9 can be used.

[0264] The terminal (1001) feeds back channel state information for the entire restored CSI-RS port channel to the base station (1002) (1050). The channel state information may be channel state information for the entire CSI-RS port, or it may be channel state information generated according to port switching information specified by the base station. The channel state information generated according to the port switching information specified by the base station may be channel state information for some CSI-RS ports, rather than channel state information for the entire CSI-RS port. The channel state information may include at least one of a rank indicator (RI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI). The channel state information is not limited to these examples, and information indicating the restored CSI-RS port channel may correspond to the channel state information.

[0265] FIG. 11 is a drawing illustrating another example of an AI-based CSI-RS compression transmission and reception process according to one embodiment of the present disclosure.

[0266] In FIG. 11, an example is shown in which a configured port switching matrix is ​​applied instead of a predetermined port switching matrix. Any actions or details omitted in FIG. 11 may refer to the corresponding configuration in FIG. 10.

[0267] The performance of CSI-RS compression and decompression can be affected by the environment of the base station cell, antenna settings, and antenna implementation. In particular, when AI model training (960) and AI model inference (970) are performed based on channel data as shown in FIG. 9, the optimal port switching matrix may differ depending on the reflection / diffraction / refraction / interference environment affecting the wireless channel. Therefore, in addition to the port switching matrix defined in the standard, the base station may perform CSI-RS compression using a port switching matrix operated by the base station itself or a cell-specific port switching matrix.

[0268] When each base station and cell uses its own port switching matrix, the base station can directly inform the terminal of the port switching matrix it intends to use. The port switching matrix can be transmitted in bitmap format via RRC signaling. Additionally, by utilizing matrix sparsity, which means there are few non-zero elements within the port switching matrix, only the positions of non-zero elements can be transmitted.

[0269] Although not shown, the terminal (1101) may report capability information indicating that it supports CSI-RS compression through a port switching matrix operated by the base station or a cell-specific port switching matrix, in addition to the standard port switching matrix defined by the base station (1102). The base station (1102) transmits the base station-specific or cell-specific port switching matrix intended for use by the terminal (1101) (1110). The base station and the terminal may allow the terminal to be trained on a port switching matrix other than the standard port switching matrix based on AI model training through intervendor collaboration. The terminal (1101) reports a port switching matrix that can be supported by the base station (1102) (1120). At this time, the terminal may support the port switching matrix indicated by offline training in the form of prior intervendor collaboration training, and the terminal may support the port switching matrix indicated by the base station by performing online training. Additionally, the terminal may report a supported port switching matrix by considering the current device's battery status, memory status, GPU availability, etc. The information indicating the port switching matrix may be at least one of the port switching matrices indicated by offline training, or information that directly indicates the port switching matrix, for example, in the form of a bitmap, which marks the position corresponding to a non-zero element in the port switching matrix as 1. Port-specific coefficients may be reported as quantized values. For example, the quantized value may be one of {1, 1 / 2, 1 / 4}.

[0270] The base station (1102) may direct a port switching matrix for AI model inference based on a supported port switching matrix reported from the terminal (1130). The directed port switching matrix may be one of the information related to CSI-RS compression settings. Additionally, depending on whether time-domain diversity or frequency-domain diversity is used, the base station may include at least one of the information related to CSI-RS compression settings in the information related to port switching settings, such as information on frequency domain resources to which a plurality of port switching indices or port switching indices (or matrices) are applied, or information on time domain resources to which a port switching index (or matrix) is applied.

[0271] The base station (1102) can compress and transmit CSI-RS based on the port switching matrix indicated to the terminal (1101) (1140). The terminal restores the channels corresponding to all CSI-RS ports based on the CSI-RS port channels compressed by the indicated port switching matrix (1150). The terminal feeds back channel state information for the restored all CSI-RS port channels to the base station (1160). The channel state information may be channel state information for all CSI-RS ports, or channel state information generated according to the port switching information specified by the base station. The channel state information generated according to the port switching information specified by the base station may be channel state information for some CSI-RS ports, rather than channel state information for all CSI-RS ports.

[0272] When multiple port switching indices are set for the entire frequency resource, channel restoration can be performed independently according to each frequency resource unit. Additionally, if different port switching indices are specified for different frequency resource units, the terminal can restore the entire CSI-RS port channel based on the CSI-RS port channels of the multiple frequency resources. Through this, the terminal can obtain performance gains in situations involving severe frequency axis selectivity or fading. Furthermore, complexity gains can be achieved in terms of implementation through the optimization of parallel computational efficiency of the AI ​​model.

[0273] A port switching matrix can be applied in two ways in the frequency domain. The first is a method in which the port switching matrix is ​​applied uniformly across the entire CSI-RS transmission band (or BWP, CSI reporting band) (hereinafter referred to as a wideband port switching instruction), or a method in which the CSI-RS transmission band is divided into subbands (SB) and a different port switching matrix is ​​applied to each subband (which may be referred to as a subband port switching instruction). The subband may include one or more RBs, and the number of the one or more RBs may be predetermined, determined based on the size of the CSI-RS transmission band, or set. Alternatively, the subband may be based on a unit of a specific frequency band rather than an RB. Whether a wideband pattern or a subband pattern is applied can be predetermined or set.

[0274] FIG. 12 is a diagram illustrating an example of a method for setting port switching index(s) according to frequency resource units in a procedure in which a base station instructs a terminal to a port switching index.

[0275] The above port switching index instruction may be associated with step 1020 of FIG. 10 and step 1130 of FIG. 11. In the port switching index instruction process, the base station may use a wideband port switching instruction (1201) to perform the same port switching for the entire subband (e.g., the entire BWP) to the terminal. Alternatively, the base station may instruct a plurality of port switching indices for each subband (1202). Referring to FIG. 12, in the case of the wideband port switching instruction (1201), a specific port switching index (e.g., port transformation index p (1211)) is instructed for the entire frequency resource (e.g., SB 0, ..., SB K (1212)). The terminal may perform CSI-RS port channel restoration according to the instructed port switching index p (1211).

[0276] If a base station intends to use different port transformation matrices on a sub-band basis, it may set different port transformation indices for each sub-band (1202). For example, the base station may instruct K port transformation indices (e.g., port transformation index p-1, ..., port transformation pK (1221)) to each of K sub-bands. These may be instructed according to the channel state for each sub-band and may be instructed considering the base station implementation. In addition, when the port transformation index to be instructed (e.g., port transformation index p-1, ..., port transformation index pk (1222)) is instructed to K (>k) sub-bands (1212), a single port transformation index may be instructed redundantly to multiple sub-bands. A certain rule may be used as a method for setting the redundant indices. For example, when port transformation indices are instructed to sub-bands in a round-robin manner, the base station may specify the order of the port transformation indices and apply the port transformation indices sequentially starting from the sub-band that starts. Alternatively, the port switching index to be applied in a round-robin manner starting from a predetermined port switching index may be specified, or the configured order and port switching index may be repeated and applied to each subband.

[0277] FIG. 13 is a diagram illustrating an example in which a port switching instruction is included in csi-ReportSubConfig to perform a CSI sub-report for CSI reporting on some CSI-RS ports.

[0278] Generally, a base station can transmit a compressed CSI-RS port to a terminal and instruct it to report a sub-report for a subset of CSI-RS ports regarding said CSI-RS port channel. For example, assuming that a base station compresses N CSI-RS ports into M CSI-RS ports and transmits them, and the terminal reconstructs the N CSI-RS port channel from the M CSI-RS port channel measurement, the base station can instruct CSI sub-report configuration information to set the terminal to reconstruct and report the n CSI-RS port channel, which is smaller than N, from the m CSI-RS port channel estimate, which is smaller than M.

[0279] Referring to FIG. 13, as shown in 1301, the base station may instruct the terminal to switch the M CSI-RS port to the N CSI-RS port using a port switching matrix. At this time, the terminal may restore the N CSI-RS port channel from the M CSI-RS port channel (csi-ReportSubConfig 1). The information instructing the port switching matrix may include configuration information for reporting channel status information. The configuration information for reporting channel status information may further include at least one of the configuration information related to channel status information reporting included in Table 16, etc.

[0280] The base station may instruct the restoration of some n CSI-RS port channels among the N CSI-RS port channels from an m CSI-RS port channel estimate smaller than M by indicating some submatrix in the port switching matrix. For example, the base station may instruct the restoration of the upper CSI-RS antenna port channel (1322) in terms of antenna shape by indicating the location of the submatrix (1321) corresponding to m1 and n1 in the port switching matrix (1311) used in 1301 (csi-ReportSubConfig 2, 1302). At this time, the terminal receives the CSI-RS port corresponding to 1323 and may restore the CSI-RS port channel corresponding to 1322 from the channel estimate for the CSI-RS port corresponding to 1323.

[0281] In addition, the base station may instruct the restoration of the lower CSI-RS antenna port channel (1332) in terms of antenna shape by indicating the location of the submatrix (1331) corresponding to m2 and n2 in the port switching matrix used in 1301 (csi-ReportSubConfig 3, 1303). At this time, the terminal receives the CSI-RS port corresponding to 1333 and can restore the CSI-RS port channel corresponding to 1332 from the channel estimate for the CSI-RS port corresponding to 1333.

[0282] The base station can indicate the values ​​of m and n and the location of the submatrix through RRC parameters. The above indication method can reduce RRC overhead compared to indicating the entire submatrix in the form of a bitmap. The base station can indicate L submatrixes through L CSI sub-reports. The CSI-RS compression transmission and reception method using the above submatrix can gain an advantage in terms of energy saving during downlink data transmission.

[0283] <2nd Example>

[0284] A second embodiment relates to a method utilizing frequency-domain diversity in a CSI-RS compression method according to one embodiment of the present disclosure mentioned in FIG. 10 and FIG. 11.

[0285] When restoring the entire N CSI-RS port channel from the compressed M CSI-RS port channel, the base station can perform the configuration of the compressed M CSI-RS port channel identically for every frequency resource. As previously illustrated in FIG. 12, in a wideband port switching instruction, the compressed port channel can be configured identically for each frequency resource unit (e.g., subband) based on the same port switching matrix for all frequency resources.

[0286] In contrast, different port switching matrices can be used for each frequency resource unit by utilizing frequency axis diversity. When frequency axis diversity is used, there can be an advantage in terms of restoration performance because the antenna correlation between frequencies can be used for the overall CSI-RS port channel restoration.

[0287] FIG. 14a illustrates an example of performing CSI-RS compression using frequency-axis diversity. FIG. 14a illustrates an example of performing CSI-RS compression using frequency-axis diversity by configuring 2 RBs into a single subband (RB 0 corresponds to the first RB within the subband, and RB 1 corresponds to the second RB within the subband).

[0288] The base station may indicate and use different port switching matrices for each frequency resource unit within the subband. Referring to FIG. 14a, for example, the base station performs CSI-RS compression using different port switching matrices for the CSI-RS port channel (1401) for RB 0 and the CSI-RS port channel (1403) for RB 1 (1430). In terms of antenna port shape, for RB 0, the CSI-RS port corresponding to the first row of the entire CSI-RS port shape (1402) is selected and compressed (1406), and for RB 1, the CSI-RS port corresponding to the second row of the entire CSI-RS port shape (1404) is selected and compressed (1408).

[0289] That is, FIG. 14a is an example of performing CSI-RS compression (1430) per RB based on a port sampling method that selects different CSI-RS ports. Accordingly, the terminal can estimate the compressed CSI-RS port channels per frequency resource unit within the subband and obtain the estimated channels from different CSI-RS ports. That is, the terminal can obtain the compressed CSI-RS port channel (1405) of RB 0 and the compressed CSI-RS port channel (1407) of RB 1. FIG. 14a illustrates an example in which two RBs form a single subband and different port switching matrices are applied to each RB, but the embodiments of the present disclosure are not limited by this example. Multiple RBs may form a single subband, and it is possible to apply different port switching matrices to two or more frequency bands within a single subband.

[0290] FIG. 14b illustrates an example of a method for restoring the entire CSI-RS port channel for a CSI-RS port channel compressed in RB units at a terminal. FIG. 14b illustrates an example in which the frequency resource unit is set to RB in relation to FIG. 14a, and an example is illustrated in which 2 RBs are used as one subband to perform CSI-RS compression based on different port sampling per RB within the subband. Referring to FIG. 14b, the terminal obtains the compressed CSI-RS port channel (1409) of RB 0 and the compressed CSI-RS port channel (1411) of RB 1 through channel estimation based on the compressed CSI-RS measurements of RB 0 and RB 1. Based on the CSI-RS antenna port shape, the terminal obtains the CSI-RS port channel of the first row (1410) for RB 0 and the CSI-RS port channel of the second row (1412) for RB 1.

[0291] The terminal performs aggregation based on antenna shape for the estimated values ​​of the compressed CSI-RS port channels for each RB (1440). The terminal can obtain aggregated port channels (1413) through the compressed port aggregation (1440). The obtained aggregated port channels may consist of the first row of antenna port shapes at RB 0 and the second row of antenna port shapes at RB 1 in terms of antenna shape (1414).

[0292] The aggregated port channels obtained above may vary depending on the port switching matrix used by the base station during CSI-RS compression. For example, as illustrated in FIG. 14b, if the compression ratio is 1 / 2 per RB and port aggregation is performed for two RBs, channels for all CSI-RS ports can be obtained based on the aggregated port channels. Generalized, if K frequency resource units are used for a compression ratio r with a total of N ports per frequency resource, the aggregated port channels can obtain channels for up to rKN ports. The terminal performs a procedure to restore (1450) all CSI-RS port channels per frequency resource unit using the aggregated port channels as input. An AI model may be used for the restoration of all CSI-RS port channels. For example, referring to FIG. 14b, the terminal can obtain the all port channels restored for RB 0 (1415) and the all port channels restored for RB 1 (1416).

[0293] FIG. 15a illustrates an example of using a frequency-axis aggregation-based CSI-RS compression technique to obtain frequency-axis diversity, and FIG. 15b illustrates an example of a port transformation index including a compression ratio and a port transformation matrix according to a frequency resource unit when using a frequency-axis aggregation-based CSI-RS compression technique to obtain frequency-axis diversity.

[0294] The base station and the terminal can perform CSI-RS compression based on different port switching indices. For ease of explanation, this description assumes that the minimum unit of frequency resources is an RB, but is not limited thereto; the minimum unit of frequency resources may be a subband unit composed of multiple RBs. Additionally, for ease of explanation, N CSI-RS ports are used, and the number of aggregated CSI-RS ports for K RBs is assumed to be M. For example, when the same number of CSI-RS ports are compressed and transmitted per RB, the number of compressed CSI-RS ports transmitted for a single RB may be M / K. It is also possible to compress and transmit a different number of CSI-RS ports per RB. For example, the number of compressed CSI-RS ports in the k-th RB is M k If defined as follows CSI-RS compression can be performed in a manner that satisfies [the condition]. The procedure for obtaining M compressed CSI-RS port channels can be performed based on the content described in FIG. 14a.

[0295] Referring to Figures 15a and 15b, the number of compressed CSI-RS ports M is determined by the product of the total number of CSI-RS ports N and the compression ratio r (i.e., M = rN). Therefore, the number of compressed CSI-RS ports per RB is M / K = rN / K. For example, 1500 in Figure 15a illustrates the case where port switching index 1 in Figure 15b is applied. When performing CSI-RS compression for K=4 RBs with a compression ratio of 1 / 2 at port switching index 1, the number of compressed CSI-RS ports is M = N / 2, and the number of compressed CSI-RS ports per RB can be N / 8. Specifically, for 1500, the total number of CSI-RS ports N is 16, and since the compression ratio is 1 / 2, the number of compressed CSI-RS ports M is 8. Since 8 antenna ports are divided and transmitted to 4 RBs, the number of compressed CSI-RS ports per RB becomes 2.

[0296] As described above, a specific port switching matrix A can represent compression from a total of N CSI-RS ports to rN / K CSI-RS ports. Specifically, the port switching index can be a single port switching matrix composed of port switching submatrices for K RBs. For example, since the number of compressed CSI-RS ports for a total of 4N CSI-RS ports corresponding to 4 RBs from port switching index 1 is M=N / 2, the dimension of the port switching matrix A can be N / 2 × 4N. According to the above port switching matrix, CSI-RS can be compressed by performing fixed port switching on the RBs included within the subband.

[0297] Alternatively, the base station can perform CSI-RS compression by instructing a port switching matrix for each RB included within the subband. 1530 in Fig. 15a is an example where port switching index 2 in Fig. 15b is applied. When port switching index 2 is applied, the total N CSI-RS ports can be compressed into M=N / 2 CSI-RS ports based on four port switching matrices having N / 8×N dimensions for four RBs. A non-zero element α in the port switching matrix i is a coefficient used for CSI-RS port compression and can represent the power per CSI-RS port. All α i If is the same, the CSI-RS port is compressed with the same power, and α depends on the AI ​​model performance or base station cell. i The above port switching index can be adjusted. As illustrated in FIGS. 10 and FIGS. 11, the port switching matrix indicator can be used.

[0298] The port switching matrix and index of FIG. 15b may be predefined as described above, or may be set between the terminal and the base station as described above.

[0299] FIG. 16 is a diagram illustrating an example of a port switching instruction per frequency resource unit. As illustrated in FIG. 16, when utilizing frequency axis diversity, the base station can instruct the terminal to switch ports per frequency resource unit. The port switching instruction may be based on the transmission of a port switching index, or the base station may directly transmit a port switching matrix to be applied per frequency resource unit.

[0300] In the example of FIG. 16, CSI-RS compression is performed on all 6 RBs (RB 0, RB 1, RB 2, RB 3, RB 4, RB 5). The 6 RBs (1601) perform CSI-RS compression in units of 2 subbands (SB 0, SB 1) (1602), SB 0 consists of RB 0, RB 1, RB 2, and RB 3, and SB 1 consists of RB 4 and RB 5 (1602). The base station can indicate a port switching index according to the number of RBs within the subband. Referring to case 1 (1603) of FIG. 16, the base station can instruct the port switching index of K=4 RB (e.g., port switching index 1 and port switching index 2 according to FIG. 15b) for SB 0, and the port switching index of K=2 RB (e.g., port switching index 3 and port switching index 4 according to FIG. 15b) for SB 1.

[0301] The port switching index indication may be based on a fixed port switching matrix for all RBs of the subband. For example, in case 1 (1603), the base station may indicate a port switching index 1 for SB 0, thereby indicating port switching that represents compression for a total of 4N CSI-RS ports from RB 0 to RB 3. Similarly, the base station may indicate a port switching index 3 for SB 1, thereby indicating port switching that represents compression for a total of 2N CSI-RS ports for RB 0 and RB 1. Based on the indicated port switching matrix, the terminal can obtain a total of N CSI-RS port channels for each RB through compressed port aggregation and AI-based channel restoration as shown in FIG. 14b using the compressed CSI-RS measurements.

[0302] Referring to case 2 (1604) of FIG. 16, when performing frequency axis aggregation, a port switching matrix per RB can be indicated. According to FIG. 15a and 15b above, it is possible to use a fixed port switching matrix for the entire subband (port switching index 1 and port switching index 3 in FIG. 15b), as well as to indicate a port switching matrix per RB within the subband (port switching index 2 and port switching index 4 in FIG. 15b). Thus, the base station can indicate a port switching matrix for the RBs within the subband. For example, in case 2 (1604), port switching index 2 can be indicated for SB 0, and port switching matrices A1, A2, A3, and A4 can be indicated for RB 0, RB 1, RB 2, and RB 3, respectively. In this case, the port switching matrices for A1, A2, A3, and A4 can be indicated for different RBs. For example, A2 can be assigned to RB 0, A3 to RB 1, A4 to RB 2, and A1 to RB 3. Similarly, port switching index 4 can be assigned to SB 1, and A1 and A2 can be assigned to RB 0 and RB 1, respectively, and different port switching matrices can be assigned to RB (e.g., port switching matrix A2 to RB 0 and port switching matrix A1 to RB 1). Furthermore, the assignment of port switching matrices is not limited to this example.

[0303] <3rd Example>

[0304] A third embodiment relates to a method utilizing time-domain diversity in a CSI-RS compression method according to an embodiment of the present disclosure mentioned in FIG. 10 and FIG. 11. FIG. 17a is a diagram illustrating an example of port switching per CSI-RS period for time-domain diversity, and FIG. 17b is a diagram illustrating an example of a port switching index per CSI-RS period for time-domain diversity.

[0305] In FIGS. 17a and 17b, it is assumed that a total of N CSI-RS ports are compressed into M (≤N) CSI-RS ports based on the compression ratio. The M compressed CSI-RS port channels can be obtained through P CSI-RS cycles. Referring to FIG. 17b, the port switching index may include P port switching matrices corresponding to P CSI-RS cycles. For example, based on a port switching index of 2, a total of N CSI-RS ports may be compressed into M=N / 2 CSI-RS ports during P=2 CSI-RS cycles. At this time, two port switching matrices (A t0 , A t1 ) can be used. 1710 in Fig. 17a illustrates the CSI-RS ports transmitted in each CSI-RS cycle when port switching index 2 is indicated. Each port switching matrix can compress a total of N CSI-RS ports into N / 4 CSI-RS ports for one CSI-RS cycle. Similarly, based on port switching index 1, four port switching matrices (A) for P=4 CSI-RS cycles t0 , A t1 , A t2 , A t3 Based on ), N CSI-RS ports can be compressed into N / 8 CSI-RS ports for each CSI-RS cycle. 1700 in FIG. 17a illustrates the CSI-RS ports transmitted in each CSI-RS cycle when port switching index 1 is indicated. The port switching index can be used to indicate the port switching matrix as shown in FIG. 10 and FIG. 11.

[0306] The base station can instruct the terminal to a port switching index corresponding to the port switching matrix to be used, considering the antenna correlation for each CSI-RS cycle. For example, at port switching index 2, in the first CSI-RS cycle of P=2 CSI-RS cycles, A t0 It directs, and in the second CSI-RS cycle, A t1 It can instruct. Also, in the first CSI-RS cycle, A t1 It directs, and in the second CSI-RS cycle, A t0 Can instruct.

[0307] As described above, the number of CSI-RS periods to which the port switching matrix is ​​applied (or may be combined with time resources to which the port switching matrix is ​​applied) may correspond to the number of port switching matrices included in the indicated port switching index, or it may be set separately by the base station. Additionally, while FIGS. 17a and b illustrate an example in which multiple port switching matrices are indicated when a single port switching index is indicated, it is also possible to indicate the number of CSI-RS periods and the port switching matrix to be applied to each period. The port switching matrix may be applied to the CSI-RS of each period, for example, in the case of periodic CSI-RS transmission, or it may be applied per specific time domain unit.

[0308] Figure 18 is a diagram illustrating an example of a procedure for performing CSI-RS compression using time axis diversity.

[0309] Referring to FIG. 18, the base station compresses a total of N CSI-RS ports into M CSI-RS ports based on P port switching matrices included in port switching index i during a total of P CSI-RS cycles from the i-th CSI-RS cycle (1801) to the (i+P-1)-th CSI-RS cycle (1802). Specifically, the base station [compresses] the port switching matrix included in port switching index i during the i-th CSI-RS cycle (1801). Based on (1811), N CSI-RS ports can be compressed into M / P CSI-RS ports. Similarly, the port switching matrix included at port switching index i in the (i+P-1)th CSI-RS cycle (1802). Based on (1812), N CSI-RS ports can be compressed into M / P CSI-RS ports. The base station transmits the CSI-RS corresponding to the compressed CSI-RS ports.

[0310] The terminal can obtain M / P port channels (1821) from M / P compressed CSI-RS port measurements for each CSI-RS cycle. The terminal can obtain M CSI-RS port channels (1831) based on the P M / P port channels obtained from the i-th CSI-RS cycle to the (i+P-1)-th CSI-RS cycle. The terminal can use the obtained M CSI-RS port channels (1831) as input to restore N CSI-RS port channels (1851) based on a channel restoration algorithm (1841). An AI model may be used in the channel restoration algorithm.

[0311] FIG. 19 is a block diagram illustrating the structure of a terminal according to one embodiment of the present disclosure.

[0312] Referring to FIG. 19, the terminal may include a transceiver (1901), a memory (1902), and a processor (1903). 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 the components described above. In addition, at least some or all of the transceiver (1901), the memory (1902), and the processor (1903) may be implemented in the form of a single chip.

[0313] In one embodiment, the transceiver (1901) can transmit and receive signals with a base station. The above-described signal may include control information and data. To this end, the transceiver (1901) 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. Additionally, the transceiver (1901) can receive a signal through a wireless channel and output it to a processor (1903), and transmit the signal output from the processor (1903) through a wireless channel.

[0314] In one embodiment, the memory (1902) may store programs and data necessary for the operation of the terminal. Additionally, the memory (1202) may store control information or data included in signals transmitted and received by the terminal. The memory (1902) 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 (1902) may be composed of multiple memories. According to one embodiment, the memory (1902) may store a program for reporting channel status information.

[0315] In one embodiment, the processor (1903) can control a series of processes that allow the terminal to operate according to the embodiments of the present disclosure described above. In one embodiment, the processor (1903) can receive information such as settings for receiving CSI-RS and settings for reporting channel status from a base station by executing a program stored in memory (1902), and can control a channel status information reporting operation based on the settings information.

[0316] FIG. 20 is a block diagram illustrating the structure of a base station according to one embodiment of the present disclosure.

[0317] Referring to FIG. 20, the base station may include a transceiver (2001), a memory (2002), and a processor (2003). However, the components of the base station are not limited to the examples described above. For example, the terminal may include more components or fewer components than the components described above. In addition, the transceiver (2001), the memory (2002), and the processor (2003) may be implemented in the form of a single chip.

[0318] In one embodiment, the transceiver (2001) can transmit and receive signals with a terminal. The above-described signal may include control information and data. To this end, the transceiver (2001) 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. Additionally, the transceiver (2001) may receive a signal through a wireless channel and output it to a processor (2003), and transmit the signal output from the processor (2003) through a wireless channel.

[0319] In one embodiment, the memory (2002) may store programs and data necessary for the operation of the base station. Additionally, the memory (2002) may store control information or data included in signals transmitted and received by the base station. The memory (2002) 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 (2002) may be composed of multiple memories. According to one embodiment, the memory (2002) may store a program for executing an operation for CSI-RS compression.

[0320] In one embodiment, the processor (2003) can control a series of processes to enable the base station to operate according to the embodiments of the present disclosure described above. In one embodiment, the processor (2003) can control operations to transmit CSI-RS compression setting information, channel status information reporting setting information, etc. to a terminal, compress and transmit CSI-RS, and receive channel status information reporting by executing a program stored in memory (2002).

[0321] Methods according to the claims or embodiments described in the specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0322] When implemented in software, a computer-readable storage medium or computer program product storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium or computer program product are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute methods according to the claims or embodiments described in the specification of this disclosure.

[0323] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), magnetic disc storage devices, CD-ROM (Compact Disc-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0324] Additionally, the program may be stored on an attachable storage device accessible via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0325] 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.

[0326] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples provided to facilitate the explanation of the technical content of the present disclosure and to aid in understanding the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it is obvious to those skilled in the art that other variations based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments may be combined and operated together as needed. For example, parts of one embodiment of the present disclosure and another embodiment may be combined to operate a base station and a terminal. In addition, the embodiments of the present disclosure are applicable to other communication systems, and other variations based on the technical concept of the embodiments may also be possible. For example, the embodiments may be applied to LTE systems, 5G or NR systems, etc.

Claims

In a method performed by a terminal of a wireless communication system, A step of receiving compression setting information related to a channel state information reference signal (CSI-RS) from a base station; A step of receiving the CSI-RS corresponding to the compressed CSI-RS port from the base station based on the compression setting information related to the CSI-RS; A step of obtaining a first channel state based on the CSI-RS corresponding to the received compressed CSI-RS port; A step of obtaining a second channel state corresponding to all or part of the CSI-RS ports based on the above-mentioned acquired channel state; and The method includes the step of transmitting channel state information to the base station that indicates a second channel state corresponding to all or part of the CSI-RS ports, and The above compressed CSI-RS port corresponds to a part of the above entire CSI-RS port, and A method characterized in that the above-mentioned compressed CSI-RS port is based on the above-mentioned entire CSI-RS port and port switching matrix. In paragraph 1, It further includes the step of reporting information on a port switching matrix that can be supported by the above base station, and A method characterized by including information regarding the above-mentioned supportable port switching matrix, which includes information indicating at least one of the predetermined port switching matrices or information indicating at least one port switching matrix. In paragraph 1, the compression setting information includes a port switching index applied to a frequency axis resource, and A method characterized in that the above port switching index is information about different port switching matrices applied to each of a plurality of subbands. In paragraph 1, the compression setting information includes a port switching index applied to a time axis resource, and A method characterized in that the above port switching index is information about different port switching matrices applied to each of a plurality of time resources. In a method performed by a base station of a wireless communication system, A step of transmitting compression setting information related to a channel state information reference signal (CSI-RS) to a terminal; A step of transmitting the CSI-RS corresponding to the compressed CSI-RS port corresponding to the compression setting information related to the CSI-RS to the terminal; and The method includes the step of receiving channel status information from the terminal that indicates a second channel status corresponding to all or part of the CSI-RS ports, and The above second channel state is derived from the first channel state corresponding to the compressed CSI-RS port, and The above compressed CSI-RS port corresponds to a part of the above entire CSI-RS port, and A method characterized in that the above-mentioned compressed CSI-RS port is based on the above-mentioned entire CSI-RS port and port switching matrix. In paragraph 5, The method further includes the step of receiving information about a port switching matrix that can be supported from the terminal, and A method characterized by including information regarding the above-mentioned supportable port switching matrix, which includes information indicating at least one of the predetermined port switching matrices or information indicating at least one port switching matrix. In paragraph 5, the above compression setting information includes a port switching index applied to the frequency axis resource, and A method characterized in that the above port switching index is information about different port switching matrices applied to each of a plurality of subbands. In paragraph 5, the above compression setting information includes a port switching index applied to a time axis resource, and A method characterized in that the above port switching index is information about different port switching matrices applied to each of a plurality of time resources. In a terminal of a wireless communication system, At least one transceiver; At least one processor connected to the above at least one transceiver so as to be able to communicate; and Connected to communicate with at least one processor and capable of executing individually or in any combination of the at least one processor, the terminal: Receive compression setting information related to the channel state information reference signal (CSI-RS) from the base station, and Based on the compression setting information related to the above CSI-RS, the above CSI-RS corresponding to the compressed CSI-RS port is received from the base station, and Acquire a first channel state based on the CSI-RS corresponding to the received compressed CSI-RS port, and Based on the above-mentioned acquired channel state, a second channel state corresponding to all or part of the CSI-RS ports is acquired, and A memory storing a command to transmit channel state information indicating a second channel state corresponding to all or part of the CSI-RS ports to the base station; comprising The above compressed CSI-RS port corresponds to a part of the above entire CSI-RS port, and A terminal characterized in that the above-mentioned compressed CSI-RS port is based on the entire CSI-RS port and port switching matrix. In paragraph 9, the above command causes the terminal to report information about a port switching matrix that is supported by the base station, and A terminal characterized by including information regarding the above-mentioned supportable port switching matrix, which includes information indicating at least one of a predetermined port switching matrix or information indicating at least one port switching matrix. In paragraph 9, the above compression setting information includes a port switching index applied to the frequency axis resource, and A terminal characterized in that the above port switching index is information regarding different port switching matrices applied to each of a plurality of subbands. In paragraph 9, the above compression setting information includes a port switching index applied to a time axis resource, and A terminal characterized in that the above port switching index is information about different port switching matrices applied to each of a plurality of time resources. In a base station of a wireless communication system, At least one transceiver; At least one processor connected to the above at least one transceiver so as to be able to communicate; and Connected to communicate with at least one processor and capable of executing individually or in any combination of the at least one processor, the base station: Transmit compression configuration information related to the channel state information reference signal (CSI-RS) to the terminal, and Transmit the CSI-RS corresponding to the compressed CSI-RS port corresponding to the compression setting information related to the CSI-RS to the above terminal, and A memory storing a command to receive channel status information indicating a second channel status corresponding to all or part of the CSI-RS ports from the terminal; comprising The above second channel state is derived from the first channel state corresponding to the compressed CSI-RS port, and The above compressed CSI-RS port corresponds to a part of the above entire CSI-RS port, and A base station characterized by the above-mentioned compressed CSI-RS port being based on the above-mentioned entire CSI-RS port and port switching matrix. In paragraph 13, the above command causes the base station to receive information about a supported port switching matrix from the terminal, and A base station characterized by including information regarding the above-mentioned supportable port switching matrix, which includes information indicating at least one of a predetermined port switching matrix or information indicating at least one port switching matrix. In paragraph 13, the compression setting information includes a port switching index applied to a frequency axis resource, and the port switching index is information regarding different port switching matrices applied to each of a plurality of subbands, or A base station characterized in that the above compression setting information includes a port switching index applied to a time axis resource, and the port switching index is information about different port switching matrices applied to a plurality of time resources.

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