Method and apparatus for transmitting or receiving channel state information in a wireless communication system

Abstract

A method and an apparatus for transmitting or receiving channel state information in a wireless communication system are disclosed. According to an embodiment of the present disclosure, a method performed by a terminal in the wireless communication system includes: receiving one or more channel state information-reference signals (CSI-RS) from a network; calculating a channel quality indicator (CQI) based on a specific precoding matrix indicator (PMI) that is one of a plurality of PMIs corresponding to a plurality of time units, respectively; and transmitting a CSI report to the network, the CQI including codebook information corresponding to the plurality of PMIs, wherein the one CQI may be associated with the specific time unit that is one of the plurality of time units and the specific PMI.

Description

[Technical field]

[0001] The present disclosure relates to wireless communication systems, and more particularly, to methods and apparatus for transmitting or receiving channel state information in wireless communication systems. [Background technology]

[0002] Mobile communication systems were developed to provide voice services while ensuring user activity. However, the scope of mobile communication systems has expanded beyond voice to data services, and currently, resource shortages are occurring due to the explosive increase in traffic, and users are demanding faster services, so there is a demand for more advanced mobile communication systems.

[0003] The requirements for the next generation mobile communication system are to accommodate large and explosive data traffic, dramatically increase the transmission rate per user, accommodate a significantly increased number of connected devices, and support very low end-to-end latency and high energy efficiency. To this end, various technologies such as Dual Connectivity, Massive Multiple Input Multiple Output (MAMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), super wideband support, and Device Networking are being researched. Summary of the Invention [Problem to be solved by the invention]

[0004] A technical problem of the present disclosure is to provide a method and apparatus for transmitting or receiving channel state information (CSI) in a wireless communication system.

[0005] A further technical object of the present disclosure is to provide a method and apparatus for transmitting or receiving a CSI report including a codebook corresponding to precoding matrix indication information for multiple time units in a wireless communication system.

[0006] The technical problems to be achieved by the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Means for solving the problem]

[0007] A method performed by a terminal in a wireless communication system according to one embodiment of the present disclosure includes: receiving one or more channel state information-reference signals (CSI-RS) from a network; calculating a channel quality indicator (CQI) based on a specific PMI among a plurality of precoding matrix indicators (PMIs) corresponding to a plurality of time units, respectively; and transmitting a CSI report to the network, the CQI including codebook information corresponding to the plurality of PMIs, wherein the one CQI may be associated with the specific time unit among the plurality of time units and the specific PMI.

[0008] A method performed by a base station in a wireless communication system according to a further aspect of the present disclosure includes a step of transmitting one or more channel state information-reference signals (CSI-RS) to a terminal, and a step of receiving a CSI report from the terminal including one channel quality indicator (CQI) and codebook information corresponding to multiple precoding matrix indicators (PMIs), wherein the one CQI is calculated based on a specific PMI which is one of multiple PMIs corresponding to multiple time units, respectively, and the one CQI may be associated with the specific time unit which is one of the multiple time units and the specific PMI. Effect of the Invention

[0009] According to the present disclosure, a method and apparatus for transmitting or receiving channel state information (CSI) in a wireless communication system can be provided.

[0010] According to the present disclosure, a method and apparatus for transmitting or receiving a CSI report including a codebook corresponding to precoding matrix indication information for multiple time units in a wireless communication system can be provided.

[0011] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief description of the drawings]

[0012] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide examples of the present disclosure and, together with the detailed description, explain the technical features of the present disclosure.

[0013] [Figure 1] 1 illustrates the structure of a wireless communication system to which the present disclosure is applicable. [Diagram 2] 1 illustrates a frame structure in a wireless communication system to which the present disclosure is applicable. [Diagram 3] 1 illustrates a resource grid in a wireless communication system to which the present disclosure is applicable. [Figure 4] 1 illustrates a physical resource block in a wireless communication system to which the present disclosure is applicable. [Diagram 5] 1 illustrates an example of a slot structure in a wireless communication system to which the present disclosure is applicable. [Figure 6] 1 illustrates examples of physical channels used in a wireless communication system to which the present disclosure is applicable, and a general method of transmitting and receiving signals using the physical channels. [Figure 7] 1 illustrates a multiple TRP transmission method in a wireless communication system to which the present disclosure can be applied. [Figure 8]FIG. 13 is a diagram for explaining an example of a CSI report transmission method of a terminal according to the present disclosure. [Figure 9] FIG. 13 is a diagram for explaining an example of a CSI report receiving method of a base station according to the present disclosure. [Figure 10] FIG. 13 is a diagram for explaining an example of a CSI reference resource and a CSI reporting time unit according to the present disclosure. [Figure 11] FIG. 13 is a diagram for explaining an example of a CSI reference resource and a CSI reporting time unit according to the present disclosure. [Figure 12] 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, and is not intended to show the only embodiment in which the present disclosure can be implemented. The detailed description below includes specific details to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0015] In some cases, in order to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or may be shown in the form of a block diagram focusing on the core functions of each structure and device.

[0016] In this disclosure, when an element is "coupled," "coupled," or "connected" to another element, this can include a direct connection as well as an indirect connection where there is still another element between them. Also, in this disclosure, the terms "including" or "having" specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0017] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another component, and are not used to limit the components, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0018] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural form unless the context dictates otherwise. The term "and / or" used in this disclosure means that one of the associated listed items may be included, or any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0019] The present disclosure is described with respect to a wireless communication network or wireless communication system, and operations performed in the wireless communication network may be performed in a process in which a device (e.g., a base station) that manages the wireless communication network controls the network and transmits or receives signals, or in a process in which a terminal coupled to the wireless network transmits or receives signals to or between the network.

[0020] In this disclosure, transmitting or receiving a channel includes transmitting or receiving information or signals on that channel. For example, transmitting a control channel means transmitting control information or signals on the control channel. Similarly, transmitting a data channel means transmitting data information or signals on the data channel.

[0021] In the following, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In the downlink, a transmitter may be a part of the base station, and a receiver may be a part of the terminal. In the uplink, a transmitter may be a part of the terminal, and a receiver may be a part of the base station. The base station may be expressed as a first communication device, and the terminal may be expressed as a second communication device. A base station (BS) may be replaced with terms such as a fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), access point (AP), network (5G network), AI (Artificial Intelligence) system / module, RSU (road side unit), robot, drone (UAV: Unmanned Aerial Vehicle), AR (Augmented Reality) device, VR (Virtual Reality) device, etc. In addition, a terminal may be fixed or mobile, and may be replaced with terms such as User Equipment (UE), Mobile Station (MS), user terminal (UT), Mobile Subscriber Station (MSS), Subscriber Station (SS), Advanced Mobile Station (AMS), Wireless terminal (WT), Machine-Type Communication (MTC) device, Machine-to-Machine (M2M) device, Device-to-Device (D2D) device, vehicle, road side unit (RSU), robot, Artificial Intelligence (AI) module, drone (UAV: Unmanned Aerial Vehicle), Augmented Reality (AR) device, Virtual Reality (VR) device, etc.

[0022] The following technologies may be used for various wireless access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. CDMA may be implemented by radio technologies such as Universal Terrestrial Radio Access (UTRA) and CDMA2000. TDMA may be implemented by radio technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented by radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), etc. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (registered trademark) 3rd Generation Partnership Project LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro.

[0023] For clarity of explanation, the following description will be based on a 3GPP communication system (e.g., LTE-A, NR), but the technical idea of ​​the present disclosure is not limited thereto. LTE refers to technology after 3GPP TS (Technical Specification) 36.xxx Release 8. In detail, LTE technology after 3GPP TS 36.xxx Release 10 is called LTE-A, and LTE technology after 3GPP TS 36.xxx Release 13 is called LTE-A pro. 3GPP NR refers to technology after TS 38.xxx Release 15. LTE / NR may be called a 3GPP system. "xxx" refers to a standard document detail number. LTE / NR may be called a 3GPP system. For background technology, terms, abbreviations, etc. used in the description of the present disclosure, reference may be made to matters described in standard documents published before the present disclosure. For example, the following documents may be referenced.

[0024] In 3GPP LTE, reference can be made to TS 36.211 (physical channels and modulation), TS 36.212 (multiplexing and channel coding), TS 36.213 (physical layer procedures), TS 36.300 (general description), and TS 36.331 (radio resource control).

[0025] For 3GPP NR, reference can be made to TS 38.211 (Physical channels and modulation), TS 38.212 (Multiplexing and channel coding), TS 38.213 (Physical layer procedures for control), TS 38.214 (Physical layer procedures for data), TS 38.300 (General description of NR and NG-RAN (New Generation-Radio Access Network)), and TS 38.331 (Radio resource control protocol standard).

[0026] The following terminology abbreviations may be used in this disclosure:

[0027] - BM: Beam management

[0028] - CQI: channel quality indicator

[0029] - CRI: channel state information- reference signal resource indicator

[0030] - CSI: channel state information

[0031] - CSI-IM: channel state information-interference measurement

[0032] - CSI-RS: Channel state information-reference signal

[0033] - DMRS: Demodulation Reference Signal

[0034] - FDM: Frequency division multiplexing

[0035] - FFT: Fast Fourier transform

[0036] - IFDMA: Interleaved frequency division multiple access

[0037] - IFFT: inverse fast Fourier transform

[0038] - L1-RSRP: Layer 1 reference signal received power

[0039] - L1-RSRQ: Layer 1 reference signal received quality

[0040] - MAC: medium access control

[0041] - NZP: non-zero power

[0042] - OFDM: Orthogonal frequency division multiplexing

[0043] - PDCCH: physical downlink control channel

[0044] - PDSCH: physical downlink shared channel

[0045] - PMI: Precoding matrix indicator

[0046] - RE: resource element

[0047] - RI: Rank indicator

[0048] - RRC: Radio resource control

[0049] - RSSI: received signal strength indicator

[0050] - Rx: Reception

[0051] - QCL: quasi co-location

[0052] - SINR: signal to interference and noise ratio

[0053] - SSB (or SS / PBCH block): Synchronization signal block (including primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH))

[0054] - TDM: time division multiplexing

[0055] - TRP: transmission and reception point

[0056] - TRS: Tracking reference signal

[0057] - Tx: transmission

[0058] - UE: User Equipment

[0059] - ZP: Zero power

[0060] System in general

[0061] As more communication devices require larger communication capacity, the need for improved mobile broadband communication compared to existing radio access technologies (RATs) is emerging. Massive Machine Type Communications (MTC), which connects a large number of devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system design considering reliability and latency-sensitive services / terminals is also being discussed. Thus, the introduction of next-generation RATs considering eMBB (enhanced mobile broadband communication), Mmtc (massive MTC), URLLC (Ultra-Reliable and Low Latency Communication), etc. is being discussed, and for convenience in this disclosure, the technology is referred to as NR. NR is an expression representing an example of 5G RAT.

[0062] New RAT systems including NR use an OFDM transmission scheme or a similar transmission scheme. The new RAT system may follow OFDM parameters different from those of LTE. Alternatively, the new RAT system may follow the existing LTE / LTE-A numerology but support a larger system bandwidth (e.g., 100 MHz). Alternatively, one cell may support multiple numerologies. That is, terminals operating with different numerologies may coexist in one cell.

[0063] A numerology corresponds to a subcarrier spacing in the frequency domain. Different numerologies can be defined by scaling the reference subcarrier spacing by an integer N.

[0064] FIG. 1 illustrates the structure of a wireless communication system to which the present disclosure can be applied.

[0065] Referring to FIG. 1, the NG-RAN is composed of gNBs that provide an NG-Radio Access (NG-RA) user plane (i.e., a new access stratum (AS) sublayer / Packet Data Convergence Protocol (PDCP) / Radio Link Control (RLC) / MAC / PHY) and control plane (RRC) protocol termination for the UE. The gNBs are interconnected via an Xn interface. The gNBs are also connected to a New Generation Core (NGC) via an NG interface. More specifically, the gNBs are connected to an Access and Mobility Management Function (AMF) via an N2 interface and to a User Plane Function (UPF) via an N3 interface.

[0066] FIG. 2 illustrates a frame structure in a wireless communication system to which the present disclosure can be applied.

[0067] The NR system can support multiple numerologies, where the numerology may be defined by subcarrier spacing and cyclic prefix (CP) overhead. In this case, the multiple subcarrier spacing may be derived by scaling the base (reference) subcarrier spacing by an integer N (or μ). Also, the numerology used may be selected independent of the frequency band, although it is assumed that very low subcarrier spacing is not used at very high carrier frequencies. Also, various frame structures with multiple numerologies may be supported in the NR system.

[0068] The following describes OFDM numerologies and frame structures that can be considered in the NR system. A number of OFDM numerologies supported in the NR system may be defined as shown in Table 1 below.

[0069] [Table 1]

[0070] NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in a traditional cellular band, when the SCS is 30 kHz / 60 kHz, it supports dense urban areas, lower latency, and wider carrier bandwidth, and when the SCS is 60 kHz or higher, it supports a bandwidth larger than 24.25 GHz to overcome phase noise. The NR frequency band is defined as two types of frequency ranges (FR1, FR2). FR1 and FR2 may be configured as shown in Table 2 below. Also, FR2 can mean millimeter wave (mmW).

[0071] [Table 2]

[0072] In relation to the frame structure in the NR system, the sizes of the various fields in the time domain are T c =1 / (Δf max N f ) where Δf max =480 10 3 Hz and N f= 4096. Downlink and uplink transmissions are f =1 / (Δf max N f / 100)·T c The radio frame is organized into radio frames each having a duration of T sf =(Δf max N f / 1000)·T c In this case, there may be one set of frames for the uplink and one set of frames for the downlink. Also, the transmission from the terminal in the uplink frame number i starts T TA =(N TA +N TA,offset )T c For a subcarrier spacing configuration μ, a slot is allocated within a subframe. s μ ∈{0,...,N slot subframe,μ -1}, and n s,f μ ∈{0,...,N slot frame,μ The slots are numbered in increasing order {N -1}. symb slot It consists of N consecutive OFDM symbols. symb slot is determined by the CP. s μ The start of OFDM symbol n s μ N symb slotNot all terminals can transmit and receive at the same time, which means that not all OFDM symbols in a downlink slot or uplink slot can be used. Table 3 shows the number of OFDM symbols per slot (N symb slot ), the number of slots per radio frame (N slot frame,μ ), the number of slots per subframe (N slot subframe,μ ), and Table 4 shows the number of OFDM symbols per slot, the number of slots per radio frame, and the number of slots per subframe in the extended CP.

[0073] [Table 3]

[0074] [Table 4]

[0075] FIG. 2 is an example when μ=2 (SCS is 60 kHz), and referring to Table 3, one subframe can include 4 slots. One subframe={1, 2, 4} slots shown in FIG. 2 is an example, and the number of slots that can be included in one subframe is defined as shown in Table 3 or Table 4. Also, a mini-slot can include 2, 4, or 7 symbols, or more or less symbols. In relation to physical resources in the NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, and the like may be considered. Hereinafter, the physical resources that can be considered in the NR system will be specifically described. First, in relation to antenna ports, the antenna ports are defined so that a channel on which a symbol on an antenna port is carried can be inferred from a channel on which another symbol on the same antenna port is carried. Two antenna ports are said to be in a quasi co-located (QC / QCL) relationship if the large-scale properties of a channel carrying symbols on one antenna port can be inferred from the channel carrying symbols on the other antenna port. Here, the large-scale properties include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing. FIG. 3 illustrates a resource grid in a wireless communication system to which the present disclosure can be applied.

[0076] Referring to FIG. 3, the resource grid is divided into N RB μ N sc RBEach subframe consists of 14.2 subcarriers. μ In the present embodiment, the OFDM symbol is used as an example, but is not limited to, an OFDM symbol. RB μ N sc RB One or more resource grids consisting of subcarriers and two μ N symb (μ) OFDM symbols, where N RB μ ≦N RB max,μ The above N RB max,μ represents the maximum transmission bandwidth, which may vary between uplink and downlink as well as numerology. In this case, one resource grid may be set for each μ and antenna port p. Each element of the resource grid for μ and antenna port p is called a resource element, and is represented by an index pair. JPEG2025516001000006.jpg617, where k=0,...,N RB μ N sc RB -1 is the index in the frequency domain, JPEG2025516001000007.jpg777 represents the position of a symbol within a subframe. When referring to a resource element in a slot, the index pair (k,l) is used, where l=0,...,N symb μ μ and the resource element for antenna port p. JPEG2025516001000008.jpg617 is a complex value JPEG2025516001000009.jpg911. If there is no risk of confusion or if a specific antenna port or numerology is not specified, the indexes p and μ may be dropped, so that the complex value is JPEG2025516001000010.jpg1130. Also, a resource block (RB) is N sc RB = 12 consecutive subcarriers.

[0077] Point A serves as a common reference point for the resource block grid and is obtained as follows:

[0078] - offsetToPointA for the primary cell (PCell) downlink indicates the frequency offset between point A and the lowest subcarrier of the lowest resource block that overlaps with the SS / PBCH block used by the terminal for initial cell selection. It is expressed in resource block units assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2.

[0079] - absoluteFrequencyPointA indicates the frequency-location of point A expressed as in ARFCN (absolute radio-frequency channel number).

[0080] Common resource blocks are numbered from 0 upwards in the frequency domain for a subcarrier spacing setting μ. The center of subcarrier 0 of common resource block 0 for a subcarrier spacing setting μ coincides with 'point A'. Common resource block number n CRB μThe relationship between k, l and the resource element (k, l) for the subcarrier spacing setting μ is given by the following Equation 1.

[0081]

number

[0082] In Equation 1, k is defined relative to point A such that k=0 corresponds to the subcarrier centered at point A. A physical resource block is a number ranging from 0 to N within a bandwidth part (BWP). BWP,i size,μ The numbering is from -1 to i, where i is the number of the BWP. PRB and common resource block n CRB The relationship between is given by Equation 2 below.

[0083]

number

[0084] N BWP,i start,μ is the common resource block where the BWP starts relative to common resource block 0.

[0085] Fig. 4 illustrates a physical resource block in a wireless communication system to which the present disclosure can be applied, and Fig. 5 illustrates a slot structure in a wireless communication system to which the present disclosure can be applied.

[0086] 4 and 5, a slot includes a number of symbols in the time domain. For example, in the general CP, one slot includes seven symbols, while in the extended CP, one slot includes six symbols.

[0087] A carrier includes multiple subcarriers in the frequency domain. A resource block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A bandwidth part (BWP) is defined as multiple consecutive (physical) resource blocks in the frequency domain and may correspond to one numerology (e.g., SCS, CP length, etc.). A carrier may include up to N (e.g., 5) BWPs. Data communication is performed in the activated BWPs, and only one BWP may be activated for one terminal. Each element in the resource grid is called a resource element (RE), and one complex symbol may be mapped to it.

[0088] The NR system may support up to 400 MHz per component carrier (CC). If a terminal operating in such a wideband CC always operates with the radio frequency (RF) chip for the entire CC turned on, the terminal battery consumption may increase. Alternatively, considering various use cases (e.g., eMBB, URLLC, Mmtc, V2X, etc.) operating in one wideband CC, different numerologies (e.g., subcarrier spacing, etc.) may be supported for each frequency band in the CC. Alternatively, the capability for maximum bandwidth may differ for each terminal. In consideration of this, the base station may instruct the terminal to operate only in a part of the bandwidth rather than the entire bandwidth of the wideband CC, and the part of the bandwidth is defined as a bandwidth part (BWP) for convenience. The BWP may be composed of continuous RBs on the frequency axis and may correspond to one numerology (e.g., subcarrier spacing, CP length, slot / minislot interval).

[0089] Meanwhile, the base station may set multiple BWPs even within one CC set in the terminal. For example, a BWP occupying a relatively small frequency region may be set in the PDCCH monitoring slot, and the PDSCH indicated by the PDCCH may be scheduled on a larger BWP. Alternatively, when UEs are concentrated in a specific BWP, other BWPs may be set in some terminals for load balancing. Alternatively, in consideration of frequency domain inter-cell interference cancellation between adjacent cells, some spectrums of the entire bandwidth may be excluded and both BWPs may be set in the same slot. That is, the base station may set at least one DL / UL BWP in a terminal associated with a wideband CC. The base station may activate at least one DL / UL BWP among the DL / UL BWPs set at a specific time (by L1 signaling, MAC CE (Control Element), RRC signaling, etc.). Also, the base station may instruct switching to another configured DL / UL BWP (by L1 signaling, MAC CE, RRC signaling, etc.). Or, the base station may switch to a predetermined DL / UL BWP when a timer value expires on a timer basis. In this case, the activated DL / UL BWP is defined as an active DL / UL BWP. However, in a situation where the UE is performing an initial access process or before an RRC connection is set up, the UE may not be able to receive the configuration for the DL / UL BWP. In such a situation, the DL / UL BWP assumed by the UE is defined as the initially active DL / UL BWP.

[0090] FIG. 6 illustrates examples of physical channels used in a wireless communication system to which the present disclosure can be applied, and a general signal transmission / reception method using the physical channels.

[0091] In a wireless communication system, a terminal receives information from a base station through a downlink, and transmits information to the base station through an uplink. Information transmitted and received between the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information they transmit and receive.

[0092] When a terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation such as synchronizing with a base station (S601). To this end, the terminal receives a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell identifier (ID). After that, the terminal receives a physical broadcast channel (PBCH) from the base station to obtain broadcast information within the cell. Meanwhile, the terminal can receive a downlink reference signal (DL RS) during the initial cell search stage to check the downlink channel state.

[0093] After completing the initial cell search, the terminal receives a physical downlink control channel (PDCCH) and a physical downlink shared channel (PDSCH) based on the information carried on the PDCCH, and can obtain more specific system information (S602).

[0094] Meanwhile, when the terminal first connects to the base station or has no radio resources for signal transmission, the terminal can perform a random access procedure (RACH: Random Access Procedure) to the base station (steps S603 to S606). To this end, the terminal can transmit a specific sequence as a preamble on a physical random access channel (PRACH: Physical Random Access Channel) (S603 and S605) and receive a response message to the preamble on a PDCCH and a corresponding PDSCH (S604 and S606). In the case of a contention-based RACH, a contention resolution procedure can also be performed.

[0095] After performing the above-mentioned procedures, the terminal can then perform PDCCH / PDSCH reception (S607) and Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) transmission (S608) as a general uplink / downlink signal transmission procedure. In particular, the terminal receives Downlink Control Information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and has different formats depending on its purpose.

[0096] Meanwhile, control information that a terminal transmits to a base station in an uplink or that the terminal receives from a base station includes downlink / uplink ACK / NACK (Acknowledgement / Non-Acknowledgement) signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indicator), etc. In a 3GPP LTE system, a terminal can transmit the above-mentioned control information such as CQI / PMI / RI in a PUSCH and / or a PUCCH.

[0097] Table 5 shows an example of a DCI format in an NR system.

[0098] [Table 5]

[0099] Referring to Table 5, DCI formats 0_0, 0_1, and 0_2 can include resource information related to PUSCH scheduling (e.g., UL / SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), transport block (TB) related information (e.g., MCS (Modulation Coding and Scheme), NDI (New Data Indicator), RV (Redundancy Version), etc.), HARQ (Hybrid-Automatic Repeat and request) related information (e.g., process number, DAI (Downlink Assignment Index), PDSCH-HARQ feedback timing, etc.), multi-antenna related information (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), power control information (e.g., PUSCH power control, etc.). The control information included in each DCI format may be predefined. DCI format 0_0 is used for PUSCH scheduling in one cell. The information included in DCI format 0_0 is transmitted after being CRC (cyclic redundancy check) scrambled by C-RNTI (Cell RNTI:Cell Radio Network Temporary Identifier) or CS-RNTI (Configured Scheduling RNTI) or MCS-C-RNTI (Modulation Coding Scheme Cell RNTI). DCI format 0_1 is used to indicate one or more PUSCH scheduling or configured grant (CG) downlink feedback information to the terminal in one cell. The information included in DCI format 0_1 is transmitted after being CRC scrambled by C-RNTI or CS-RNTI or SP-CSI-RNTI (Semi-Persistent CSI RNTI) or MCS-C-RNTI. DCI format 0_2 is used for PUSCH scheduling in one cell.The information included in the DCI format 0_2 is CRC scrambled by the C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI and then transmitted. Next, the DCI formats 1_0, 1_1, and 1_2 may include resource information related to PDSCH scheduling (e.g., frequency resource allocation, time resource allocation, virtual resource block (VRB)-physical resource block (PRB) mapping, etc.), transmission block (TB) related information (e.g., MCS, NDI, RV, etc.), HARQ related information (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), multiple antenna related information (e.g., antenna port, transmission configuration indicator (TCI), sounding reference signal (SRS) request, etc.), and PUCCH related information (e.g., PUCCH power control, PUCCH resource indicator, etc.), and the control information included in each of the DCI formats may be predefined.

[0100] DCI format 1_0 is used for scheduling the PDSCH in one DL cell. Information included in DCI format 1_0 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and transmitted.

[0101] DCI format 1_1 is used for scheduling the PDSCH in one cell. Information included in DCI format 1_1 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and then transmitted.

[0102] DCI format 1_2 is used for scheduling the PDSCH in one cell. Information included in DCI format 1_2 is CRC scrambled by the C-RNTI, CS-RNTI, or MCS-C-RNTI and transmitted.

[0103] Multi-TRP related operations

[0104] The Coordinated Multi Point (CoMP) technique is a method in which multiple base stations exchange (e.g., using the X2 interface) or utilize channel information (e.g., RI / CQI / PMI / LI (layer indicator)) fed back from terminals to transmit coordinated to terminals, effectively controlling interference. Depending on the method used, CoMP can be classified into joint transmission (JT), coordinated scheduling (CS), coordinated beamforming (CB), dynamic point selection (DPS), dynamic point blocking (DPB), etc.

[0105] The M-TRP transmission method, in which M TRPs transmit data to one terminal, can be broadly divided into i) eMBB M-TRP transmission, which is a method for increasing the transmission rate, and ii) URLLC M-TRP transmission, which is a method for increasing the reception success rate and reducing latency.

[0106] In addition, in terms of DCI transmission, the M-TRP transmission method can be divided into i) M-DCI (multiple DCI) based M-TRP transmission in which each TRP transmits different DCI, and ii) S-DCI (single DCI) based M-TRP transmission in which one TRP transmits DCI. For example, in the case of S-DCI based M-TRP transmission, all scheduling information for data transmitted by the M TRP needs to be transmitted to the terminal in one DCI, and it may be used in an ideal backhaul (ideal BH) environment in which dynamic coordination between both TRPs is possible.

[0107] For TDM-based URLLC M-TRP transmission, schemes 3 and 4 are currently under standardization discussion. Specifically, scheme 4 refers to a scheme in which one TRP transmits a transmission block (TB) in one slot, and has the effect of increasing the probability of data reception using the same TB received from multiple TRPs in multiple slots. In contrast, scheme 3 refers to a scheme in which one TRP transmits a TB in several consecutive OFDM symbols (i.e., symbol groups), and multiple TRPs in one slot may be configured to transmit the same TB in different symbol groups.

[0108] In addition, the UE can recognize PUSCH (or PUCCH) scheduled by DCI received in different control resource sets (CORESETs) (or CORESETs belonging to different CORESET groups) as PUSCH (or PUCCH) transmitted in different TRPs or as PDSCH (or PDCCH) in different TRPs. In addition, the method for UL transmission (e.g., PUSCH / PUCCH) transmitted in different TRPs described later can be equally applied to UL transmission (e.g., PUSCH / PUCCH) transmitted in different panels belonging to the same TRP.

[0109] In the following, multiple DCI-based non-coherent joint transmission (NCJT) / single DCI-based NCJT will be described.

[0110] NCJT (Non-coherent joint transmission) is a method in which multiple TPs (Transmission Points) transmit data to one terminal using the same time-frequency resources, and transmit data using different layers (i.e., different DMRS ports) between the TPs using different Demodulation Multiplexing Reference Signal (DMRS) ports.

[0111] The TP transmits data scheduling information to the terminal receiving the NCJT by DCI. In this case, a method in which each TP participating in the NCJT transmits scheduling information for its own transmission data by DCI is called 'multi DCI based NCJT'. Since N TPs participating in the NCJT transmission transmit DL grant DCI and PDSCH to the UE, the UE receives N DCIs and N PDSCHs from the N TPs. In contrast, a method in which one representative TP transmits scheduling information for its own transmission data and data transmitted by other TPs (i.e., TPs participating in the NCJT) by one DCI is called 'single DCI based NCJT'. In this case, N TPs transmit one PDSCH, but each TP transmits only some layers of the multiple layers that make up one PDSCH. For example, when 4-layer data is transmitted, TP1 can transmit 2 layers and TP2 can transmit the remaining 2 layers to the UE.

[0112] The multiplexed TRP (MTRP) that transmits the NCJT can transmit DL data to the terminal using one of the following two methods.

[0113] First, the 'single DCI based MTRP method' will be described. In the MTRP, one common PDSCH is transmitted cooperatively together, and each TRP participating in the cooperative transmission transmits the PDSCH by spatially dividing it in different layers (i.e., different DMRS ports) using the same time-frequency resource. At this time, the scheduling information for the PDSCH is indicated to the UE by one DCI, and the DCI indicates which DMRS (group) port uses which QCL RS and QCL type information (this is different from the existing DCI indicating the QCL RS and type commonly applied to all DMRS ports). That is, M TCI states are indicated in a TCI (Transmission Configuration Indicator) field in the DCI (e.g., M=2 in the case of two TRP cooperative transmission), and the QCL RS and type may be indicated using different M TCI states for each M DMRS port group. Also, DMRS port information may be indicated using a new DMRS table.

[0114] Next, a 'multiple DCI-based MTRP method' will be described. MTRP transmits different DCI and PDSCH, and these PDSCHs are transmitted overlapping (partially or entirely) with each other on frequency-time resources. These PDSCHs are scrambled with different scrambling IDs, and the DCIs may be transmitted by coresets belonging to different coreset groups (here, the coreset group may be identified by an index defined in the coreset setting of each coreset. For example, if coresets 1 and 2 are set to index=0 and coresets 3 and 4 are set to index=1, coresets 1 and 2 belong to coreset group 0, and coresets 3 and 4 belong to coreset group 1. Also, if no index is defined in the coreset, it can be analyzed as index=0). It can be seen that when multiple scrambling IDs are configured in one serving cell or two or more Coreset groups are configured, the UE receives data through multiple DCI-based MTRP operation.

[0115] Alternatively, whether the MTRP scheme is single DCI-based or multiple DCI-based may be indicated to the UE by separate signaling. For example, multiple cell reference signal (CRS) patterns for MTRP operation for one serving cell may be indicated to the UE. In this case, PDSCH rate matching for CRS may be changed depending on whether the MTRP scheme is single DCI-based or multiple DCI-based (since the CRS patterns are different from each other).

[0116] Hereinafter, the CORESET group identifier (group ID) described / mentioned in this disclosure may mean an index / identification information (e.g., ID) for distinguishing a CORESET for each TRP / panel. And, a CORESET group may be a group / union of CORESETs distinguished by an index / identification information (e.g., ID) for distinguishing a CORESET for each TRP / panel / the CORESET group ID. As an example, the CORESET group ID may be specific index information defined in a CORSET configuration. In this case, a CORESET group may be set / indicated / defined by an index defined in a CORESET configuration for each CORESET. And / or, the CORESET group ID may mean an index / identification information / indicator for distinguishing / identifying between CORESETs set / associated with each TRP / panel. Hereinafter, the CORESET group ID described / mentioned in the present disclosure may be expressed as a specific index / specific identification information / specific indicator for distinguishing / identifying between CORESETs set / associated with each TRP / panel. The CORESET group ID, i.e., a specific index / specific identification information / specific indicator for distinguishing / identifying between CORESETs set / associated with each TRP / panel, may be set / instructed to the terminal by higher layer signaling (e.g., RRC signaling) / Layer 2 signaling (L2 signaling, e.g., MAC-CE) / Layer 1 signaling (L1 signaling, e.g., DCI). As an example, it may be set / instructed to perform PDCCH detection for each TRP / panel (i.e., for each TRP / panel belonging to the same CORESET group) in the CORESET group unit.And / or, for each TRP / panel in the unit of the CORESET group (i.e., for each TRP / panel belonging to the same CORESET group), uplink control information (e.g., CSI, HARQ-A / N (ACK / NACK), SR (scheduling request)) and / or uplink physical channel resources (e.g., PUCCH / PRACH / SRS resources) may be set / instructed to be separately managed / controlled. And / or, for each TRP / panel in the unit of the CORESET group (i.e., for each TRP / panel belonging to the same CORESET group), HARQ A / N (processing / resending) for PDSCH / PUSCH, etc. scheduled for each CORESET group may be managed.

[0117] Hereinafter, the partially overlapped NCJP will be described.

[0118] In addition, NCJT can be distinguished into fully overlapped NCJT in which the time-frequency resources transmitted by each TP are completely overlapped and partially overlapped NCJT in which only some of the time-frequency resources are overlapped. That is, in the case of partially overlapped NCJT, data of both TP1 and TP2 are transmitted in some time-frequency resources, and only data of one of TP1 or TP2 is transmitted in the remaining time-frequency resources.

[0119] Hereinafter, a method for improving reliability in multiple (Multi-TRP) will be described.

[0120] As transmission / reception methods for improving reliability using transmission by multiple TRPs, the following two methods can be considered.

[0121] FIG. 7 illustrates a multi-TRP transmission scheme in a wireless communication system to which the present disclosure is applicable.

[0122] Referring to FIG. 7(a), a case is shown in which layer groups transmitting the same codeword (CW) / transport block (TB) correspond to different TRPs. In this case, a layer group can mean a predetermined layer set consisting of one or more layers. In this case, the amount of transmission resources increases due to the large number of layers, which has the advantage that robust channel coding with a low code rate can be used for the TB. In addition, since the channels are different from the multiple TRPs, it is expected that the reliability of the received signal can be improved based on the diversity gain.

[0123] Referring to FIG. 7(b), an example is shown in which different CWs are transmitted in layer groups corresponding to different TRPs. In this case, it can be assumed that the TBs corresponding to CW #1 and CW #2 in the figure are the same. That is, CW #1 and CW #2 mean that the same TB is converted into different CWs by channel coding or the like according to different TRPs. Therefore, it can be considered as an example of repeated transmission of the same TB. FIG. 7(b) may have a disadvantage that the code rate corresponding to the TB is higher than that of FIG. 7(a). However, it has an advantage that the code rate can be adjusted by instructing different RV (redundancy version) values ​​for encoded bits generated from the same TB according to the channel environment, or the modulation order of each CW can be adjusted.

[0124] According to the schemes illustrated in Figures 7(a) and 7(b), the same TB is repeatedly transmitted in different layer groups, and each layer group is transmitted by a different TRP / panel, thereby increasing the probability of data reception by the terminal. This is called an SDM (Spatial Division Multiplexing)-based M-TRP URLLC transmission scheme. Layers belonging to different layer groups are transmitted by DMRS ports belonging to different DMRS CDM groups.

[0125] In addition, although the above-mentioned contents related to multiple TRPs have been described based on a spatial division multiplexing (SDM) scheme using different layers, this may of course be extended and applied to a frequency division multiplexing (FDM) scheme based on different frequency domain resources (e.g., RB / PRB (set), etc.) and / or a time division multiplexing (TDM) scheme based on different time domain resources (e.g., slots, symbols, sub-symbols, etc.).

[0126] Regarding the approach for multiple TRP-based URLLC scheduled by a single DCI, the following approach is discussed:

[0127] 1) Scheme 1 (SDM): Time and frequency resource allocation overlap, and n (n <= Ns) TCI states are allocated in a single slot.

[0128] 1-a) Method 1a

[0129] - At each transmission occasion, the same TB is transmitted in one layer or set of layers, each layer or each set of layers being associated with one TCI and one DMRS port.

[0130] - A single codeword with one RV is used for all spatial layers or a set of all layers. From the UE perspective, different coded bits are mapped to different layers or sets of layers according to the same mapping rule.

[0131] 1-b) Method 1b

[0132] - At each transmission occasion the same TB is transmitted in one layer or set of layers, each layer or each set of layers being associated with one TCI and one DMRS port.

[0133] - A single codeword with one RV is used for each spatial layer or set of layers. The RVs corresponding to each spatial layer or set of layers may be the same or different.

[0134] 1-c) Method 1c

[0135] - At one transmission occasion, the same TB having one DMRS port associated with multiple TCI state indexes is transmitted on one layer, or the same TB having multiple DMRS ports associated one-to-one with multiple TCI state indexes is transmitted on one layer.

[0136] In methods 1a and 1c above, the same MCS is applied to all layers or to all sets of layers.

[0137] 2) Method 2 (FDM): Frequency resource allocation does not overlap, and n (n <= Nf) TCI states are allocated in a single slot.

[0138] - Each non-overlapping frequency resource allocation is associated with one TCI state.

[0139] - The same single / multiple DMRS ports are associated with all non-overlapping frequency resource allocations.

[0140] 2-a) Method 2a

[0141] - A single codeword with one RV is used for all resource allocations. From the UE perspective, a common RB matching (mapping of codewords to layers) is applied across all resource allocations.

[0142] 2-b) Method 2b

[0143] - A single codeword with one RV is used for each non-overlapping frequency resource allocation. The RVs corresponding to each non-overlapping frequency resource allocation may be the same or different.

[0144] For scheme 2a above, the same MCS is applied to all non-overlapping frequency resource allocations.

[0145] 3) Method 3 (TDM): Time resource allocation does not overlap, and n (n <= Nt1) TCI states are allocated in a single slot.

[0146] Each transmission occasion of the TB has a time granularity of a minislot and has one TCI and one RV.

[0147] - A common MCS is used for a single or multiple DMRS ports at all transmission occasions within a slot.

[0148] - At different transmission occasions the RV / TCI may be the same or different.

[0149] 4) Method 4 (TDM): n (n <= Nt2) TCI states in K (n <= K) different slots

[0150] Each occurrence of a TB has one TCI and one RV.

[0151] - All transmission occasions over the K slots use a common MCS for a single or multiple DMRS ports.

[0152] - The RV / TCI may be the same or different at different transmission occasions.

[0153] The following describes MTRP URLLC.

[0154] In the present disclosure, DL MTRP URLLC means that multiple TRPs transmit the same data (e.g., the same TB) / DCI using different layer / time / frequency resources. For example, TRP 1 transmits the same data / DCI using resource 1, and TRP 2 transmits the same data / DCI using resource 2. A UE configured with the DL MTRP-URLLC transmission method receives the same data / DCI using different layer / time / frequency resources. In this case, the base station configures the UE with which QCL RS / type (i.e., DL TCI state) should be used in the layer / time / frequency resource that receives the same data / DCI. For example, when the same data / DCI is received in resource 1 and resource 2, the DL TCI state used in resource 1 and the DL TCI state used in resource 2 may be configured. Since the UE receives the same data / DCI in resource 1 and resource 2, high reliability can be achieved. Such DL MTRP URLLC may be applied to the PDSCH / PDCCH.

[0155] In the present disclosure, UL MTRP-URLLC means that multiple TRPs receive the same data / UCI (uplink control information) from one UE using different layer / time / frequency resources. For example, TRP 1 receives the same data / DCI from the UE at resource 1, and TRP 2 receives the same data / DCI from the UE at resource 2, and then shares the received data / DCI through the connected backhaul link between the TRPs. A UE configured with the UL MTRP-URLLC transmission mode transmits the same data / UCI using different layer / time / frequency resources. At this time, the base station sets for the UE which Tx beam and which Tx power (i.e., UL TCI state) should be used for the layer / time / frequency resources for transmitting the same data / UCI. For example, when the same data / UCI is transmitted at resource 1 and resource 2, the UL TCI state used at resource 1 and the UL TCI state used at resource 2 may be set. Such UL MTRP URLLC may be applied to PUSCH / PUCCH.

[0156] Also, in the present disclosure, the meaning of using (or mapping) a specific TCI state (or, TCI) when receiving data / DCI / UCI for a certain frequency / time / space resource (layer) is as follows. In the DL, it can mean estimating the channel from the DMRS using the QCL type and QCL RS indicated by the TCI state for that frequency / time / space resource (layer), and receiving / demodulating the data / DCI based on the estimated channel. Also, in the UL, it can mean transmitting / modulating the DMRS and data / UCI using the Tx beam and / or power indicated by the TCI state for that frequency / time / space resource.

[0157] Here, the UL TCI state includes the Tx beam and / or Tx power information of the UE, and instead of the TCI state, spatial relation info, etc. may be set to the UE by another parameter. The UL TCI state may be directly indicated by the UL grant DCI, or may refer to spatial relation info of the SRS resource indicated by the SRI (sounding resource indicator) field of the UL grant DCI. Or, it may refer to an open loop (OL) transmit power control parameter (OL Tx power control parameter) linked to a value indicated by the SRI field of the UL grant DCI (e.g., j: index for open loop parameters Po and alpha (maximum 32 parameter value sets per cell), q_d: index of DL RS resource for pathloss (PL) measurement (maximum 4 measurements per cell), l: closed loop power control process index (maximum 2 processes per cell)).

[0158] The following describes MTRP eMBB.

[0159] In this disclosure, MTRP-eMBB means that multiple TRPs transmit different data (e.g., different TBs) using different layers / times / frequencies. A UE configured with the MTRP-eMBB transmission mode assumes that various TCI states are indicated by DCI, and the data received using the QCL RS in each TCI state is different from each other.

[0160] Meanwhile, the UE can know whether MTRP URLLC transmission / reception or MTRP eMBB transmission / reception is performed by separately distinguishing between the RNTI for MTRP-URLLC and the RNTI for MTRP-eMBB. That is, when CRC masking of DCI is performed using the RNTI for URLLC, the UE regards it as URLLC transmission, and when CRC masking of DCI is performed using the RNTI for eMBB, the UE regards it as eMBB transmission. Alternatively, the base station can set the UE to MTRP URLLC transmission / reception or TRP eMBB transmission / reception using another new signaling.

[0161] In the present disclosure, for convenience of explanation, cooperative transmission / reception between two TRPs is assumed, but the method proposed in the present disclosure may be extended to a multi-TRP environment of three or more, and may also be extended to a multi-panel environment (i.e., a TRP corresponds to a panel). Also, different TRPs may be recognized as different TCI states by a UE. Therefore, when a UE receives / transmits data / DCI / UCI using TCI state 1, it means that the UE receives / transmits data / DCI / UCI from / to TRP 1.

[0162] Hereinafter, the method proposed in the present disclosure may be used in a situation where the MTRP transmits the PDCCH cooperatively (transmits the same PDCCH repeatedly or separately). The method proposed in the present disclosure may also be used in a situation where the MTRP transmits the PDSCH cooperatively or receives the PUSCH / PUCCH cooperatively.

[0163] In addition, in the present disclosure, the meaning of multiple base stations (i.e., MTRPs) repeatedly transmitting the same PDCCH can mean that the same DCI is transmitted using multiple PDCCH candidates, and can also mean that multiple base stations repeatedly transmit the same DCI. Here, the same DCI can mean two DCIs with the same DCI format / size / payload. Or, even if the payloads of two DCIs are different, they can be said to be the same DCI if the scheduling results are the same. For example, the time domain resource allocation (TDRA) field of the DCI determines the slot / symbol position of data and the slot / symbol position of A / N (ACK / NACK) relatively based on the reception time of the DCI, but if the DCI received at time n and the DCI received at time n+1 inform the UE of the same scheduling result, the TDRA fields of the two DCIs are different, and as a result, the DCI payloads are inevitably different. The number of repetitions R may be directly instructed by the base station to the UE, or may be mutually agreed upon. Alternatively, even if the payloads of two DCIs are different and the scheduling results are not the same, if the scheduling result of one DCI is a subset of the scheduling result of the other DCI, they can be said to be the same DCI. For example, when the same data is TDM-multiplexed and repeatedly transmitted N times, DCI 1 received before the first data indicates data repetition N times, and DCI 2 received after the first data and before the second data indicates data repetition N-1 times. The scheduling data of DCI 2 is a subset of the scheduling data of DCI 1, and the two DCIs are both scheduled for the same data, so in this case as well, they can be said to be the same DCI.

[0164] In addition, in the present disclosure, when multiple base stations (i.e., MTRPs) transmit the same PDCCH in a divided manner, it means that one DCI is transmitted using one PDCCH candidate, and TRP 1 transmits some resources in which the PDCCH candidate is defined, and TRP 2 transmits the remaining resources. For example, when TRP 1 and TRP 2 transmit PDCCH candidates corresponding to aggregation level m1+m2 in a divided manner, the PDCCH candidates are divided into PDCCH candidate 1 corresponding to aggregation level m1 and PDCCH candidate 2 corresponding to aggregation level m2, and TRP 1 can transmit PDCCH candidate 1 and TRP 2 can transmit PDCCH candidate 2 in different time / frequency resources. After receiving PDCCH candidate 1 and PDCCH candidate 2, the UE can generate PDCCH candidates corresponding to aggregation level m1+m2 and attempt DCI decoding.

[0165] In addition, in the present disclosure, the UE repeatedly transmits the same PUSCH so that multiple base stations (i.e., MTRPs) can receive it, which may mean that the UE transmits the same data in multiple PUSCHs. In this case, each PUSCH may be optimized and transmitted to a UL channel of a different TRP. For example, when the UE repeatedly transmits the same data in PUSCHs 1 and 2, PUSCH 1 may be transmitted using UL TCI state 1 for TRP 1, and in this case, link adaptation such as precoder / MCS may be scheduled / applied to a value optimized for the channel of TRP 1. PUSCH 2 may be transmitted using UL TCI state 2 for TRP 2, and link adaptation such as precoder / MCS may be scheduled / applied to a value optimized for the channel of TRP 2. In this case, PUSCHs 1 and 2 transmitted repeatedly may be transmitted at different times and may be TDM, FDM, or SDM.

[0166] In addition, in the present disclosure, the meaning that the UE transmits the same PUSCH in a divided manner so that it can be received by multiple base stations (i.e., MTRPs) may mean that the UE transmits one data in one PUSCH, but divides the resources allocated to the PUSCH and transmits them in an optimized manner to UL channels of different TRPs. For example, when the UE transmits the same data in a 10-symbol PUSCH, the data is transmitted using UL TCI state 1 for TRP 1 in the first 5 symbols, and link adaptation such as precoder / MCS may be scheduled / applied with values ​​optimized for the channel of TRP 1. The remaining data is transmitted using UL TCI state 2 for TRP 2 in the remaining 5 symbols, and link adaptation such as precoder / MCS may be scheduled / applied with values ​​optimized for the channel of TRP 2. In the above example, one PUSCH is divided into time resources and transmission toward TRP 1 and transmission toward TRP 2 are TDM-based, but it may also be transmitted in other FDM / SDM manners.

[0167] Similarly to the above-described PUSCH transmission, the UE may transmit the same PUCCH repeatedly or in separate PUCCHs for reception by multiple base stations (ie, MTRPs).

[0168] Hereinafter, the proposal of the present disclosure can be expanded and applied to various channels such as PUSCH / PUCCH / PDSCH / PDCCH.

[0169] The proposal of the present disclosure can be extended to both cases where various uplink / downlink channels are repeatedly transmitted using different time / frequency / spatial resources and where they are separately transmitted.

[0170] In the present disclosure, a transmission occasion (TO) may correspond to a resource unit where a channel is transmitted / received or a candidate resource unit where a channel may be transmitted / received. For example, when multiple channels are transmitted in a TDM manner, a TO may refer to each channel that is transmitted / may be transmitted in different time resources. For example, when multiple channels are transmitted in an FDM manner, a TO may refer to each channel that is transmitted / may be transmitted in different frequency resources (e.g., RBs). For example, when multiple channels are transmitted in an SDM manner, a TO may refer to each channel that is transmitted / may be transmitted in different layers / beams / DMRS ports. One TCI state may be mapped to each TO. When the same channel is repeatedly transmitted, normal DCI / data / UCI may be transmitted to one TO, and the receiving end may receive multiple TOs to increase the reception success rate.

[0171] The above-mentioned single DCI (S-DCI) based multi-TB PUSCH / PDSCH scheduling method may be applied, for example, when one DCI simultaneously schedules multiple PUSCH / PDSCH in an ultra-high frequency band (above 5.26 GHz band). For example, a time-domain resource allocation (TDRA) field of a DCI that schedules a PUSCH may indicate multiple TDRAs (or TOs) at once, and different TBs may be transmitted via a PUSCH in each TO. The frequency domain resource allocation (FDRA), MCS, transmit precoding matrix indicator (TPMI), and SRI values ​​of the multi-TB PUSCH scheduling DCI may be commonly applied to multiple TBs scheduled by the DCI. In addition, the NDI and RV may be indicated individually / independently for each TB by the multi-TB PUSCH scheduling DCI. Also, although one value is indicated for the HARQ (process) number (HPN) in the multi-TB PUSCH scheduling DCI, sequentially increasing values ​​may be applied in the order of the TOs based on the initial TO.

[0172] Furthermore, an S-DCI-based M-TRP PUSCH repetitive transmission scheme may be considered. In this regard, the base station configures two SRS sets in the terminal for S-DCI-based M-TRP PUSCH transmission, and each set is used to indicate UL Tx ports and UL beam / QCL information for / to TRP1 and TRP2, respectively. In addition, the base station may indicate SRS resources for each SRS resource set in two SRI fields included in one DCI, and indicate up to two PC parameter sets.

[0173] For example, the first SRI field may indicate SRS resources and PC parameter sets defined in SRS resource set 0, and the second SRI field may indicate SRS resources and PC parameter sets defined in SRS resource set 1. The terminal may be indicated with a UL Tx port, PC parameter set, and UL beam / QCL information for TRP1 in the first SRI field, whereby the terminal performs PUSCH transmission in a TO corresponding to SRS resource set 0. Similarly, the terminal may be indicated with a UL Tx port, PC parameter set, and UL beam / QCL information for TRP2 in the second SRI field, whereby the terminal performs PUSCH transmission in a TO corresponding to SRS resource set 1.

[0174] In addition to the above-mentioned SRI field, the existing one field may be expanded to two fields so that TPMI, PTRS, TPC related fields can be indicated for each TRP.

[0175] Further, an SRS resource set indication field (e.g., a 2-bit field) may be defined, based on which the terminal may select a specific one of the two SRS resource sets to perform S-TRP PUSCH repeated transmission, or may select both of the two SRS resource sets to perform M-TRP PUSCH repeated transmission.

[0176] For example, the code point "0" in the SRS resource set indication field may be set / defined to indicate the first SRS resource set, and the code point "01" may be set / defined to indicate the second SRS resource set. When the code point "0" or "01" is indicated, S-TRP PUSCH transmission corresponding to the SRS resource set indicated by each code point may be performed. Furthermore, the code point "10" may be set / defined to indicate (first SRS resource set, second SRS resource set), and the code point "11" may be set / defined to indicate (second SRS resource set, first SRS resource set). When the code point "10" or "11" is indicated, M-TRP PUSCH transmission may be performed in the order in which the SRS resource set pairs are indicated. When the code point "10" is indicated, the first SRS resource set corresponds to the first PUSCH TO, and when the code point "11" is indicated, the second SRS resource set corresponds to the first PUSCH TO.

[0177] Further, a single PUCCH resource-based M-TRP PUCCH repetitive transmission scheme may be considered. In this regard, for single PUCCH resource-based M-TRP PUCCH transmission, the base station may activate / configure two pieces of spatial relation info (if FR1, activate / configure two PC parameter sets) to a single PUCCH resource in the terminal. When the UL UCI is transmitted using the PUCCH resource, each piece of spatial relation info is used to indicate the spatial relation info for TRP1 and TRP2 to the terminal. For example, the terminal is instructed of the Tx beam / PC parameters for TRP1 according to the value indicated in the first spatial relation info, and the terminal performs PUCCH transmission in the TO corresponding to TRP1 using the information. Similarly, the terminal is instructed on the Tx beam / PC parameters toward TRP2 by the value indicated in the second spatial relation info, and the terminal uses the information to transmit PUCCH in the TO corresponding to TRP2.

[0178] Also, for the M-TRP PUCCH repeated transmission, the configuration method is improved so that two spatial relation info can be configured in the PUCCH resource. That is, when power control (PC) parameters such as PLRS, Alpha, P0, and Closed loop index are configured in each spatial relation info, the spatial relation RS may be configured. As a result, PC information and spatial relation RS information corresponding to two TRPs may be configured by the two spatial relation info. In this manner, the terminal transmits UCI (i.e., CSI, ACK / NACK, SR, etc.) PUCCH using the first spatial relation info in the first TO, and transmits the same UCI PUCCH using the second spatial relation info in the second TO. In the present disclosure, the PUCCH resource in which two spatial relation info are configured may be referred to as an M-TRP PUCCH resource, and the PUCCH resource in which one spatial relation info is configured may be referred to as an S-TRP PUCCH resource.

[0179] Furthermore, in connection with the proposal of the present disclosure, a unified TCI framework scheme may be considered. That is, the DL DCI (e.g., DCI format 1_1 / 1_2, etc.) may indicate both the DL TCI status and the UL TCI status. Alternatively, the DL DCI may indicate only the UL TCI status without indicating the DL TCI status. Thus, the scheme previously used for UL beam and power control (PC) setting may be replaced by the above-mentioned UL TCI status indication scheme.

[0180] As a specific example, one UL TCI state may be indicated in the TCI field in the DL DCI. In this case, the UL TCI state may be applied to all PUSCHs / PUCCHs after a certain time (e.g., a beam application time) and may be applied to some or all of the indicated SRS resource sets. Alternatively, multiple UL TCI states (and / or DL ​​TCI states) may be indicated in the TCI field in the DL DCI.

[0181] A method in which a terminal simultaneously transmits multiple channels (CHs) / reference signals (RSs) of the same type, and a new method in which a terminal simultaneously transmits multiple CHs / RSs of different types are being discussed. In the existing method, the operation of a terminal transmitting multiple CHs / RSs at one time point (or one time unit) is restricted. For example, for a terminal according to the existing method, it is supported to simultaneously transmit multiple SRS resources belonging to different SRS resource sets for uplink beam measurement, but it is not supported to simultaneously transmit multiple different PUSCHs. Therefore, in order to relax the above restrictions and support more advanced terminal operations, a method of simultaneously transmitting multiple CHs / RSs using multiple transmission elements of one terminal is being discussed.

[0182] For example, according to the present disclosure, a terminal can simultaneously perform uplink transmission to multiple transmission targets using multiple transmission elements. Also, a base station can simultaneously receive uplink transmissions transmitted from a terminal with multiple transmission elements via multiple transmission targets. For example, a transmission element of a terminal may correspond to an antenna group or an antenna panel, and one antenna group / panel may correspond to one RS set (or a set of RS candidates). That is, an antenna group / panel may be indicated / identified by an RS (candidate) set. For example, a transmission target of an uplink transmission from a terminal may correspond to a TRP or a cell, and one TRP / cell may correspond to one CORESET group / pool. That is, a TRP / cell may be indicated / identified by a CORESET group / pool. For example, a simultaneous uplink transmission scheme to multiple transmission targets using multiple transmission elements may be referred to as STxMP (simultaneous transmission across multi-panel). However, the scope of the present disclosure is not limited by the name of such a transmission scheme, the unit of a transmission element, and / or the unit example of a transmission target.

[0183] As an example of STxMP operation, two PUSCHs corresponding to two UL TBs (e.g., a first PUSCH carrying a first TB and a second PUSCH carrying a second TB) may be scheduled in the same RE. Also, separate TCI states may be set / indicated for each of the multiple PUSCH transmissions. The multiple TCI states may correspond to multiple transmission elements (e.g., panels / RS sets). Also, each transmission element may correspond to one transmission target, or multiple transmission elements may correspond to one transmission target.

[0184] For example, a first spatial relation RS and a first power control (PC) parameter set (or a first UL TCI state) may be configured / indicated for a first PUSCH transmission, and a second spatial relation RS and a second PC parameter set (or a second UL TCI state) may be configured / indicated for a second PUSCH transmission. For example, a terminal may transmit a first PUSCH using a first panel corresponding to a first UL TCI state in a first time unit, and transmit a second PUSCH using a second panel corresponding to a second UL TCI state in the first time unit. For example, a terminal may transmit a first PUSCH using a first RS set (for a first CORESET pool) based on a first UL TCI state in a first time unit, and transmit a second PUSCH using a second RS set (for a second CORESET pool) based on a second UL TCI state in the first time unit. A time unit may correspond to one or more of a symbol, a symbol group, a slot, and a slot group.

[0185] In this regard, when scheduling a PUSCH using DCI, the base station can indicate whether the PUSCH is to be transmitted in STxMP, in a single panel, or in M-TRP PUSCH repetition. In this case, the terminal should have STxMP-related capability, and the STxMP mode should be pre-enabled by higher layer signaling (e.g., RRC signaling, etc.). For this indication, the existing SRS resource set indication field may be redefined and used, or a new DCI field may be introduced / defined.

[0186] In the present disclosure, defining certain information between a terminal and a base station means that the terminal and the base station know the information without any additional signaling between the terminal and the base station, configuring the information between the terminal and the base station means transmitting / receiving the information through higher layer (e.g., RRC) signaling between the terminal and the base station, and indicating the information between the terminal and the base station can mean transmitting / receiving the information through lower layer (e.g., L1 (e.g., DCI / UCI), L2 (e.g., MAC-CE)) signaling.

[0187] CSI improvement

[0188] The present disclosure relates to a CSI improvement scheme applicable to a high-speed terminal. For example, various examples for applying a time-domain compression window to a PMI included in CSI are described below.

[0189] In an existing wireless communication system, a codebook (e.g., a type II codebook) associated with PMI can support compressing PMI for multiple subbands in the frequency domain and reporting it as one codebook. In this disclosure, a method for compressing PMI for multiple time units in the time domain and reporting it as one codebook (i.e., included in one CSI report) is described.

[0190] For example, the present disclosure may include specific examples for the number of time units (or time instances), the interval of the time units, the position of the CSI reference resource, the window (or duration) of the time units, etc. The present disclosure may include examples for codebook parameters including time domain based coefficients, unit granularity, etc. The present disclosure may include examples for the relationship between measurement restrictions for channel measurement resources (CMR) / interference measurement resources (IMR) and time units. The present disclosure may include examples for the criteria for time unit offset.

[0191] FIG. 8 is a diagram for explaining an example of a CSI report transmission method of a terminal according to the present disclosure.

[0192] In step S810, the terminal may receive one or more CSI-RS from the network.

[0193] In step S820, the terminal may calculate one CQI based on a specific PMI, which is one of a plurality of PMIs corresponding to a plurality of time units, respectively.

[0194] In the following description, the term PMI may be translated to or include a precoding matrix indicated by the PMI.

[0195] One CQI may be associated with a specific time unit among a plurality of time units. Also, one CQI may be associated with a specific PMI among a plurality of PMIs. For example, a terminal may be configured to report at least one CQI, and one CQI may be associated with a specific time unit / specific PMI.

[0196] For example, the particular time unit may correspond to the first or earliest time unit among multiple time units within a set window.

[0197] For example, the particular time unit may correspond to a CSI reference resource.

[0198] For example, a first time unit of the multiple time units within a set window may correspond to a CSI reference resource.

[0199] For example, a particular PMI may be the first / earliest PMI (or a matrix that the PMI points to) that corresponds to a particular time unit (eg, the first / earliest time unit).

[0200] For example, the particular time unit may correspond to a time unit that is a particular offset away from the time unit in which the CSI report is transmitted (eg, the CSI report instance).

[0201] For example, the duration of one time unit may be equal to the CSI-RS period, and multiple time units may have the same time duration (i.e., the duration of a first time unit may be equal to the duration of a second time unit), such that multiple time instances may be equally spaced in the time domain.

[0202] In step S830, the terminal may transmit a CSI report including one CQI and codebook information corresponding to a plurality of PMIs to the network.

[0203] The codebook information corresponding to the multiple PMIs may include a codebook index (or a combination of multiple codebook indexes) corresponding to each of the multiple PMIs.

[0204] A CSI report may include other information in addition to a single CQI and codebook information, and may be transmitted in a single reporting instance or in multiple reporting instances (i.e., information included in a single CSI report is transmitted at different times / channels).

[0205] FIG. 9 is a diagram for explaining an example of a CSI report reception method of a base station according to the present disclosure.

[0206] In step S910, the base station may transmit one or more CSI-RS to the terminal.

[0207] In step S920, the base station may receive a CSI report including one CQI and codebook information corresponding to a plurality of PMIs from the terminal, and the one CQI may be calculated based on a specific PMI, which is one of a plurality of PMIs corresponding to a plurality of time units, respectively.

[0208] Here, specific examples of one CQI, multiple PMIs, and time units corresponding to the multiple PMIs are the same as those described with reference to FIG. 8, and therefore, the same description will not be repeated.

[0209] In the following, a specific example of a CSI report including codebook information for multiple PMIs corresponding to multiple time units according to the present disclosure will be described.

[0210] The following examples may be applied, for example, for possible CSI improvement for high / medium terminal speeds, but this does not limit the scope of application of the present disclosure, and the examples of the present disclosure may be applied for various purposes for more accurate and efficient CSI reporting.

[0211] For high / medium terminal speeds, aspects of type II codebook improvement may be considered, as well as terminal reporting of time domain channel properties such as Doppler shift or Doppler spread using TRS. Such considerations may help the base station (e.g., gNB) to perform better link level adaptation to time varying channels due to high terminal mobility.

[0212] In particular, an improved type II codebook including time domain compression can provide the base station with precoding information for multiple time instances (or time units) instead of a single time instance (or time unit) vulnerable to channel aging. This allows the base station to predict the time-varying channel direction and schedule a better MCS and precoder. Meanwhile, by calculating and reporting Doppler information using TRS in addition to the existing CSI, the terminal can help the base station compensate for outdated CSI using Doppler information. This allows the base station to predict the time-varying channel direction and schedule a better MCS and precoder.

[0213] Examples of this disclosure describe channel measurements, the time instances (or time units) that the new codebook represents, the time domain basis (TD basis), etc., for Type II codebook improvements.

[0214] First, the channel measurements for type II codebook refinement are described.

[0215] Type II codebook improvements including time domain (TD) compression can require multiple channel measurements at the terminal side. In operation where the terminal performs multiple channel measurements, the time domain channel / interference measurement restriction of the terminal can be enabled / disabled by the base station.

[0216] If enabled, the terminal may measure the latest CMR / IMR no later than the CSI reference resource, so that a single measurement may be used to estimate the channel on the CSI reference resource.

[0217] When disabled, the terminal can measure multiple CMR / IMR instances that are not later than the CSI reference resource. How to use multiple measurements to estimate a channel on the CSI reference resource may vary depending on the implementation of the terminal. In this way, for an unrestricted (i.e., restriction disabled) measurement configuration, the terminal can calculate CSI using multiple measurements. When codebook improvements including TD compression are introduced, an unrestricted measurement configuration may be necessary for the terminal to calculate PMI for multiple time instances.

[0218] That is, multiple channel measurements at the terminal side may be required for type II codebook improvement including TD compression. Also, if no time restriction (e.g., timeRestrictionForChannelMeasurements parameter) for channel measurements is set, the terminal can calculate CSI including an improved codebook based on TD compression using multiple channel / interference measurements. Also, if a time restriction (e.g., timeRestrictionForChannelMeasurements parameter) is set, the terminal calculates CSI using a single channel / interference measurement, so that the improved codebook including TD compression may not be available.

[0219] Whether multiple channel measurements are possible may depend not only on the time domain measurement limitations as mentioned above, but also on the periodicity of the CMR / IMR. In the case of aperiodic (AP) CMR / IMR, only a single measurement is possible since there is only one CMR / IMR with no periodicity. Periodic (P) / semi-static (SP) CMR / IMR provides multiple opportunities for the terminal to measure the channel / interference. For example, assuming a minimum period of 4 slots, it is necessary to investigate whether a high-speed terminal is provided with sufficiently frequent measurement instances. If the measurement instances are too sparse, the PMI accuracy may decrease and the quality of TD compression may be poor. Or, if the measurement instances are too dense, the CSI-RS overhead may increase.

[0220] That is, only one measurement is possible since there is only one CMR / IMR with no periodicity for the AP CMR / IMR. A method for the P / SP CSI-RS to define / configure / indicate multiple time instances (or time units) to provide sufficient measurement time instances for an improved Type II codebook with TD compression will be described later with specific examples of the present disclosure.

[0221] Next, we will describe multiple time instances (or time units) represented by an improved Type II codebook with TD compression.

[0222] Similar to the existing type-II codebook with frequency domain (FD) compression that represents multiple PMIs for multiple subbands, the new type-II codebook with TD compression can represent multiple PMIs for multiple time instances (or time units), where multiple time instances are required to be determined / defined.

[0223] 10 and 11 are diagrams for explaining examples of CSI reference resources and CSI reporting time units according to the present disclosure.

[0224] The CSI including the PMI / RI / CQI can represent a channel for a single time instance called a CSI reference resource. That is, a single CQI included in the CSI may be calculated based on one PMI among multiple PMIs corresponding to multiple time units. For example, the time unit and the PMI to which the one CQI is associated may be the first / earliest time unit and the first / earliest PMI corresponding thereto in the example of FIG. 10. Or, the time unit and the PMI to which the one CQI is associated may be the last time unit and the last (e.g., the third in the case of three PMIs) PMI corresponding thereto in the example of FIG. 11.

[0225] A Type II codebook with TD compression can provide PMI not only for the CSI reference resource but also for other time instances (e.g., slots / symbols), which may be defined later or earlier in the time domain compared to the CSI reference resource.

[0226] The example of FIG. 10 shows PMI for multiple time units that are no earlier than the CSI reference resource.

[0227] The terminal calculates PMI based on the CSI reference resource. ref_rsc The terminal may calculate the PMI based on a resource that is τ time units later than the CSI reference resource, which may be derived from a periodic CMR that is no later than the CSI reference resource. ref_rsc+τ Calculate the PMI based on the resource 2τ time units after the CSI reference resource. ref_rsc+2τFor example, assuming that the CSI reference resource is located in slot l, the terminal can calculate the PMI based on the DL channel in slot l+τ. ref_rsc+τ , and PMI based on DL channel in slot l+2τ ref_rsc+2τ , ... can be calculated.

[0228] This will allow PMI ref_rsc , PMI ref_rsc+τ , PMI ref_rsc+2τ , ... may be compressed by using an improved Type II codebook including TD compression, and the PMI feedback overhead may be reduced. A codebook including PMI at a future time point compared to the CSI reporting time point (e.g., slot n) is robust to channel aging since the terminal is required to predict the DL channel at a time point after the CSI reference resource, and the base station can use it for better link adaptation.

[0229] The example of FIG. 11 shows PMI for multiple time units that are no later than the CSI reference resource.

[0230] The terminal calculates PMI based on the CSI reference resource. ref_rsc The terminal can calculate the PMI based on a resource that is τ time units earlier than the CSI reference resource, which may be derived from a periodic CMR that is no later than the CSI reference resource. ref_rsc-τ Calculate the PMI based on the resource 2τ time units before the CSI reference resource. ref_rsc-2τ For example, assuming that the CSI reference resource is located in slot l, the terminal can calculate the PMI based on the DL channel in slot l-τ as ref_rsc-τ , and PMI based on DL channel in slot l-2τ ref_rsc-2τ , ... can be calculated.

[0231] The example of Figure 11 shows that periodic CMR exists in the CSI reference resource, CSI reference resource-τ, and CSI reference resource-2τ. That is, in the example of Figure 11, the interval between multiple time units corresponding to multiple PMIs is the same as τ, and τ may be the same as the period of the periodic CMR (e.g., P / SP-CSI-RS). Also, the example of Figure 10 shows an example in which the interval between multiple time units corresponding to multiple PMIs is the same as τ, and τ may be the same as the period of the periodic CMR (e.g., P / SP-CSI-RS), for example.

[0232] This will allow PMI ref_rsc , PMI ref_rsc-τ , PMI ref_rsc-2τ , ... may be compressed by using an improved type II codebook including TD compression, which may reduce PMI feedback overhead. A codebook including PMI from a time point in the past compared to the CSI reporting time point (e.g., slot n) may reduce the complexity of the terminal operation compared to the example of FIG. 10 because it does not require the terminal to predict the DL channel. ref_rsc-τ , PMI ref_rsc-2τ , ...is PMI ref_rsc , and therefore may be difficult to use or realize potential gains for better link adaptation at the base station.

[0233] That is, as illustrated in Figures 10 and / or 11, multiple time instances represented by the improved Type II codebook can be defined / configured that are located earlier and / or later in the time domain compared to the CSI reference resource.

[0234] Next, the TD basis for improving the type II codebook is explained.

[0235] As described with reference to Figures 10 and 11, to address channel aging effects due to high mobility, a terminal may calculate multiple PMIs for multiple time instances. The PMI feedback payload may increase linearly as the number of time instances associated with a PMI increases. Even if multiple PMIs share the same spatial domain (SD) and / or frequency domain (FD) basis, at least distinct coefficient values ​​must be reported for each PMI, which may occupy a dominant portion of the payload.

[0236] Therefore, time-domain compression using TD basis for coefficient values ​​can have an advantageous effect for feedback overhead reduction. Considering the existing Type-II codebooks in which SD basis and FD basis are independently selected based on DFT matrix, TD basis may also be selected independently of SD basis and / or FD basis.

[0237] Alternatively, the beam direction of each SD basis may be completely / partially aligned with the moving direction of the terminal or may be opposite to the moving direction, and each SD basis may experience different levels of time-varying channels. In consideration of this, if different TD bases can be selected for different SD bases, the codebook accuracy can be improved.

[0238] In other words, the TD basis can be defined / set by comprehensively considering the aspect of reducing feedback overhead using TD compression and the performance gain when applying a specific TD basis selection of SD basis / FD basis.

[0239] Example 1

[0240] In the examples described with reference to FIGS. 10 and 11, the time instances (e.g., CSI reporting windows) of the channels represented by the PMI may be defined / set as follows:

[0241] For example, information regarding the length of the CSI reporting window, the number of time instances (or time units) in the window, the interval between the time instances, etc. may be predefined without signaling between the terminal and the base station, or may be set in the terminal by signaling from the base station. In the following, an example will be described assuming that a window of time instances of a channel represented by a PMI is set for a terminal by a base station, but the examples of the present disclosure may also be applied to time instances that are predefined (or defined as default values) without signaling from the base station.

[0242] For example, the base station may signal the window of time instances to the terminal using parameters included in the RRC signaling for the codebook configuration.

[0243] How many time instances are represented by the PMI (i.e., information on the number of time instances in a window) may be set / instructed to the terminal. In the examples of Figs. 10 and 11, the number of time instances may be assumed to be three. The number of time instances may be set in consideration of the time variation of the channel, and for this purpose, the terminal may report its own speed information, Doppler information (e.g., Doppler shift / Doppler spread), etc. to the base station. Alternatively, the terminal may report a preferred number of time instances based on its own speed or Doppler information to the base station, and the base station may approve or consider it, select a time instance number value to be finally applied, and notify the terminal. Additionally or alternatively, the terminal may report candidate values ​​for the time instance number value to the network as capability information.

[0244] Information regarding the interval between time instances (i.e., τ in the examples of FIG. 10 and FIG. 11) may be set / instructed to the terminal. The τ value may be set taking into consideration the time variation of the channel, and for this purpose, the terminal may report its own speed information, Doppler information (e.g., Doppler shift / Doppler spread), etc. to the base station. Alternatively, the terminal may report a preferred τ value based on its own speed or Doppler information to the base station, and the base station may approve it or take it into consideration and select a τ value to be finally applied and notify the terminal. For example, the τ value may be expressed as an absolute time length, number of slots, number of OFDM symbols, etc. The terminal may also report candidate values ​​for the τ value to the network as capability information.

[0245] Additionally or alternatively, as in the above example, the interval between the time instances may be set to be the same as the periodic CMR (or the interval or period between P / SP-CSI-RS). The interval between the time instances may also be said to be the duration of each time instance. That is, information regarding the interval between the time instances or the duration of the time instances may be separately configured / instructed to the terminal, or the terminal may be configured / instructed to apply the same value as the period provided by a specific CSI-RS configuration.

[0246] The terminal may be configured / instructed as to which time instance the CSI reference resource corresponds to among the time instances.

[0247] In the example of FIG. 10, the first / earliest time instance may correspond to the CSI reference resource. The example of FIG. 10 may correspond to a case where the offset between the CSI reference resource and the time instance is 0. For example, the base station may configure / indicate information regarding the offset between the CSI reference resource and the time instance to the terminal. When the CSI reference resource corresponds to the first / earliest time instance, one or more remaining time instances may be located after the CSI reference resource in the time domain. Also, as described above, when the CSI reference resource corresponds to the first / earliest time unit (e.g., slot) in the window, a single CQI may be associated with one first / earliest time unit and one corresponding (i.e., first / earliest) PMI.

[0248] In the example of FIG. 11, the last time instance may correspond to the CSI reference resource. The example of FIG. 11 may correspond to a case where the offset between the CSI reference resource and the time instance is 2 (or 2τ). For example, the base station may configure / instruct the terminal with information regarding the offset between the CSI reference resource and the time instance. When the CSI reference resource corresponds to the last time instance, one or more remaining time instances may be located before the CSI reference resource in the time domain. Also, as described above, when the CSI reference resource corresponds to the last time unit (e.g., slot) in the window, a single CQI may be associated with the last one time unit and one PMI corresponding thereto (e.g., the third of three PMIs).

[0249] In the above example, the offset for the time instance (i.e., the time domain interval with the CSI reference resource) may be set taking into account the time variation of the channel, and for this purpose, the terminal may report its velocity information, Doppler information (e.g., Doppler shift / Doppler spread), etc. to the base station. Alternatively, the terminal may report a preferred time instance offset based on its velocity or Doppler information to the base station, and the base station may approve it or take it into account, select a time instance offset to be finally applied, and notify the terminal.

[0250] For example, a time instance offset related capability in which a CSI reference resource can be set as the last time instance in a window (as in FIG. 11) and a time instance offset related capability in which a CSI reference resource can be set as the first time instance in a window (as in FIG. 10) may be defined. That is, one terminal may support only the former capability, another terminal may support only the latter capability, and yet another terminal may support both the former and latter capabilities. Such terminal capabilities may be reported to the network. The former capability does not require channel prediction, so that terminal implementation is simple, but the latter capability requires channel prediction, so that terminal implementation may be complex. Specifically, in the latter case, the terminal may further report to the network a configurable minimum value of the time instance offset (i.e., associated with the terminal's prediction performance) or a candidate for a configurable time instance offset value (i.e., associated with the terminal's prediction performance). For example, the smaller the minimum value of the time instance offset, the more predictions must be performed, which may increase the complexity of the terminal implementation.

[0251] In the above examples, the location of the time instances in the time domain (e.g., grid) may be defined / set by the number and interval of the time instances, and the slot / symbol in which the grid of the time instances is located may be defined / determined by the time instance offset with respect to the CSI reference resource.

[0252] Additionally or alternatively, the length of a window of time instances may be defined / set as a number of time units (e.g., slots / symbols) and the number of time instances within the window may be defined / set to define / set the location of the time instances in the time domain (e.g., grid). That is, time instances that are equally spaced apart by the number of time instances within the window may be determined. Or, time instances that have the same duration within the window may be determined. For example, if the length of the window is defined as 3 slots and the number of time instances is 3, the time instance grid may be expressed as 3 consecutive slots. That is, the duration of each time instance may be 1 slot.

[0253] In this case, if the time instance offset value is given as 0, the final time instance may be determined to be slot index l, slot index l+1, and slot index l+2 corresponding to the CSI reference resource slot.

[0254] In the above example, the time instances are set at equal intervals (or the duration of each time instance is the same). Additionally or alternatively, if the time variation of the channel varies over time and is predictable, it may be inefficient to distribute the time instances at equal intervals (or with the same duration). For example, when N time instances are set, assume a situation in which the channel time variation is strong at the front (i.e., early time) of the entire time interval represented by the PMI and weak at the rear (i.e., late time) of the entire time interval. In this case, the time instances may be arranged more densely (i.e., with narrow intervals or short duration) at the front of the entire time interval, and more sparsely (i.e., with wide intervals or long duration) at the rear of the entire time interval. For example, if the CSI reference resource (slot l) is located at the first time instance, the second time instance may be located at slot l+1, the third time instance may be located at slot l+2, and the fourth time instance may be located at slot l+5. This allows for improved compression ratio and accuracy for TD compression.

[0255] In this way, the time instances in the window may be equally spaced (or have the same duration) or may not be equally spaced (or may have different durations). In this regard, the terminal may transmit information related to the positions of the time instances to the network (together with the CSI report). Alternatively, the base station may configure / instruct the terminal to the information related to the positions of the time instances. For example, the base station may provide the terminal with information related to the positions of the time instances using the UL scheduling DCI that triggers the AP CSI report.

[0256] Among the information / parameters related to time instances as described above (e.g., window length, number of time instances in the window, interval between time instances, time instance duration, time instance position, etc.), some parameters are fixed (i.e., no signaling is required between the terminal and the base station), and the remaining parameters can be set by the base station to the terminal or reported by the terminal to the base station.

[0257] The parameters of the codebook to be compressed by the TD compression may change according to the time instances set as above. For example, the fewer the number of time instances in the same window length, the larger the interval between the time instances (or the duration of the time instances), or the longer the window length, the more time the TD compression should be performed on. Appropriate TD basis candidates may change in such various cases. For example, when the TD basis candidates are configured based on the DFT matrix, the DFT matrix may be configured as a function of the number of time instances or the interval between the time instances. In addition, when the SD / FD / TD basis is linearly combined, the unit size (or the configurable range of the unit size) of the applied coefficients (e.g., amplitude, phase) may also be adjusted. For example, when the number of time instances increases, the number of coefficients may increase, and the unit size of the coefficients may be increased to offset the corresponding increase in overhead, and the number of candidate values ​​that can be expressed within the range of the coefficient value may be reduced. Also, instead of reporting all the coefficients in a type II codebook, some coefficients may be set to 0 (zero) and only values ​​for non-zero coefficients may be reported. The setting (or the settable range) for the number of such zero-valued coefficients may also vary depending on the number of time instances or the time interval between time instances.

[0258] The base station can provide the terminal with information, for example by RRC signaling, regarding whether to set the time instance as the CSI reference resource and a resource (or slot) located thereafter in the time domain as in FIG. 10, or as the CSI reference resource and a resource (or slot) located before it in the time domain as in FIG. 11.

[0259] Also, a CMR / IMR measurement restriction period may be determined in association with the PMI time instance. For example, as shown in FIG. 11, when slot l, slot l-τ, and slot l-2τ are set as time instances (or CSI reporting windows) represented by PMI, the DL channel of slot l may be restricted to be measured using the CMR / IMR existing before slot l or slot l and after slot l-τ or slot l-τ, the DL channel of slot l-τ may be restricted to be measured using the CMR / IMR existing before slot l-τ or slot l-τ and after slot l-2τ or slot l-2τ, and the DL channel of slot l-2τ may be restricted to be measured using the CMR / IMR existing before slot l-2τ or slot l-2τ and after slot l-3τ or slot l-3τ (or existing before slot l-2τ without any restriction on after any time boundary). With such restrictions, the base station can control the implementation of channel / interference measurements of the terminal for CSI calculation. As a result, the base station receives CSI calculated by a common implementation from multiple terminals, thereby enabling the base station to unify the process of compensating the CSI for a time-varying channel and calculating PMI / MCS, etc.

[0260] Example 2

[0261] In the examples above, the time instance offset is described as a position relative to a CSI reference resource.

[0262] Additionally or alternatively, a time instance offset (or a position of a CSI reference resource included in the time offset) may be defined / configured based on the CSI reporting time point (e.g., slot n in Figures 10 and 11).

[0263] Additionally or alternatively, a time instance offset (or a position of a CSI reference resource included in the time offset) may be defined / configured based on the last time unit of a CSI measurement window (which is distinguished from a CSI reporting window). The CSI measurement window may refer to a time interval (or a time unit) during which a channel / interference may be measured for CSI calculation, and the CSI reporting window may refer to a time interval (or a time unit) corresponding to a channel represented by the CSI.

[0264] In the above examples, the time instance offset may be set to a negative number or a value equal to or greater than the number of time instances. When the time instance offset is set as a relative position to the CSI reference resource, if the time instance offset is a negative number, the time instance may exist only at a future time point compared to the CSI reference resource. If the time instance offset is set to a value equal to or greater than the number of time instances, the time instance may exist only at a past time point compared to the CSI reference resource.

[0265] The terminal can report the possible range of the time instance offset to the base station (e.g., as capability information). The base station can set / instruct the terminal to set a time instance offset value (e.g., within the range reported by the terminal) in consideration of the report information from the terminal.

[0266] Values ​​for various information / parameters provided to the terminal described in the above examples may be set / indicated in the case of AP CSI reporting by (together with) the AP CSI reporting trigger field of the UL scheduling DCI, by parameters in the CSI-ReportConfig IE, and / or by PMI codebook related configuration information.

[0267] The terminal may also report the maximum value of each of the number of time instances and the time instance interval to the base station (e.g., as capability information). The larger the number of time instances or the time instance interval, the greater the amount of calculation required by the terminal for CSI calculation. Therefore, the terminal may report to the base station the maximum value for the number of time instances and / or the time instance interval that affects the amount of CSI calculation. The base station may set / instruct the number of time instances and / or the time instance interval to the terminal in consideration of the maximum value reported from the terminal (e.g., within a range not exceeding the maximum value).

[0268] Additionally or alternatively, the terminal may report information on the number of time instances and the combination of time instance intervals to the base station (e.g., as terminal capability information). For example, the terminal may separately report a combination of how many maximum intervals there are when there are N1 time instances and a combination of how many slots there are when there are N2 time instances. Alternatively, the terminal may separately report a combination of how many time instances there are when the maximum interval is S1 slots and a combination of how many time instances there are when the maximum interval is S2 slots. Such a reporting method may be effective because the greater the number of time instances, the smaller the maximum interval supported by the terminal (or the greater the maximum interval, the smaller the number of time instances).

[0269] This reporting method can also be applied when a time instance is defined / configured using a window of time instances instead of an interval of time instances by replacing the interval of time instances with the length of the window of time instances. For example, the terminal can report capability information for the length of the window and / or the number of time instances to the base station. The base station can provide configuration / instruction information for the length of the window and / or the number of time instances to the terminal. For example, when the time instances have equal intervals (or the same duration), the length of the window can be defined / configured as the product of the interval of the time instances (or the duration of the time instances) and the number of time instances.

[0270] Apparatus to which the present disclosure is applicable

[0271] FIG. 12 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure.

[0272] Referring to FIG. 12, a first wireless device 100 and a second wireless device 200 can transmit and receive wireless signals using various wireless access technologies (eg, LTE, NR).

[0273] The first wireless device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may be configured to control the memory 104 and / or the transceiver 106 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. For example, the processor 102 may process information in the memory 104 to generate a first information / signal, and then transmit a wireless signal including the first information / signal from the transceiver 106. The processor 102 may also receive a wireless signal including a second information / signal from the transceiver 106, and then store information obtained from signal processing of the second information / signal in the memory 104. The memory 104 may be coupled to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for performing some or all of the processes controlled by the processor 102 or executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a wireless communication technology (e.g., LTE, NR). The transceiver 106 may be coupled to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be referred to as a Radio Frequency (RF) unit. In the present invention, a wireless device may mean a communication modem / circuit / chip.

[0274] The second wireless device 200 may include one or more processors 202, one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may be configured to control the memory 204 and / or the transceiver 206 to implement the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. For example, the processor 202 may process information in the memory 204 to generate a third information / signal, and then transmit a wireless signal including the third information / signal from the transceiver 206. The processor 202 may also receive a wireless signal including a fourth information / signal from the transceiver 206, and then store information obtained from signal processing of the fourth information / signal in the memory 204. The memory 204 may be coupled to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for performing some or all of the processes controlled by the processor 202 or executing the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to embody a wireless communication technology (e.g., LTE, NR). The transceiver 206 may be coupled to the processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be referred to as an RF unit. In the present invention, a wireless device may mean a communication modem / circuit / chip.

[0275] The hardware elements of the wireless device 100, 200 are described in more detail below. Without being limited thereto, one or more protocol layers may be embodied by one or more processors 102, 202. For example, one or more processors 102, 202 may embody one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors 102, 202 may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure. The one or more processors 102, 202 can generate and provide signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information to one or more transceivers 106, 206 according to the functions, procedures, suggestions, and / or methods disclosed in this disclosure. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 and obtain the PDUs, SDUs, messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this disclosure.

[0276] The one or more processors 102, 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. The one or more processors 102, 202 may be embodied in hardware, firmware, software, or a combination thereof. As an example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in the present disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be included in one or more processors 102, 202 or stored in one or more memories 104, 204 and executed by one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods and / or operational flowcharts disclosed in the present disclosure may be embodied in firmware or software in the form of code, instructions and / or collections of instructions.

[0277] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories 104, 204 may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer readable storage media, and / or combinations thereof. The one or more memories 104, 204 may be located internal and / or external to the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques, such as wired or wireless coupling.

[0278] The one or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as referred to in the methods and / or operational flow diagrams of the present disclosure, to one or more other devices. The one or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as referred to in the descriptions, functions, procedures, suggestions, methods and / or operational flow diagrams of the present disclosure, from one or more other devices. For example, the one or more transceivers 106, 206 may be coupled to one or more processors 102, 202 and may transmit and receive wireless signals. For example, the one or more processors 102, 202 may control the one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, the one or more processors 102, 202 may control the one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be coupled to one or more antennas 108, 208, and the one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, radio signals / channels, etc., as described, functions, procedures, suggestions, methods, and / or operation flow diagrams disclosed in the present disclosure, via the one or more antennas 108, 208. In the present disclosure, the one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). The one or more transceivers 106, 206 may convert the received radio signals / channels, etc., from RF band signals to baseband signals for processing the received user data, control information, radio signals / channels, etc., using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, radio signals / channels, etc., processed using one or more processors 102, 202, from baseband signals to RF band signals. To that end, one or more of the transceivers 106, 206 may include (analog) oscillators and / or filters.

[0279] The above-described embodiments are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered as optional unless otherwise expressly stated. Each component or feature may be implemented in a form not combined with other components or features. It is also possible to combine some components and / or features to configure the embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some configurations or features of one embodiment may be included in another embodiment, or may be replaced with corresponding configurations or features of another embodiment. It is clear that claims that do not have an explicit reference relationship in the claims may be combined to configure an embodiment, or may be included as a new claim by amendment after filing.

[0280] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted as limiting in any respect, but should be considered as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the attached claims, and any modifications within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0281] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause a device or computer to perform operations according to the methods of various embodiments, and non-transitory computer-readable media on which such software or instructions or the like can be stored and executed on a device or computer. Instructions available for programming a processing system to perform features described in the present disclosure may be stored on / in a storage medium or computer-readable storage medium, and computer program products including such storage media may be used to embody features described in the present disclosure. The storage medium may include high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, but is not limited thereto, and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices that are located remotely from the processor. The memory or alternatively the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure may be embodied in software and / or firmware stored on any one of a number of machine-readable media and capable of controlling the hardware of a processing system and allowing the processing system to interact with other mechanisms that utilize the results of embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0282] Here, the wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure can include, in addition to LTE, NR, and 6G, Narrowband Internet of Things (NB-IoT) for low-power communication. At this time, for example, the NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented according to standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-mentioned names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure can communicate based on LTE-M technology. At this time, as an example, the LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, the LTE-M technology may be implemented by at least any one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-mentioned names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure can include at least any one of ZigBee (registered trademark), Bluetooth (registered trademark), and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-mentioned names. As an example, the ZigBee technology can generate PAN (personal area networks) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and may be called by various names.

Industrial Applicability

[0283] The method proposed in this disclosure has been described mainly as being applied to 3GPP LTE / LTE-A and 5G systems, but it can also be applied to various wireless communication systems other than 3GPP LTE / LTE-A and 5G systems.

Claims

1. 1. A method performed by a terminal in a wireless communication system, the method comprising: receiving one or more channel state information-reference signals (CSI-RS) from a network; calculating a channel quality indicator (CQI) based on a specific precoding matrix indicator (PMI), the specific PMI being one of a plurality of precoding matrix indicators (PMIs) corresponding to a plurality of time units, respectively; transmitting a CSI report to the network, the CSI report including codebook information corresponding to the one CQI and the plurality of PMIs; The method, wherein the one CQI is associated with a particular time unit, the particular time unit being one of the plurality of time units, and the particular PMI.

2. The method of claim 1 , wherein the particular time unit is a first time unit of the plurality of time units within a set window.

3. The method of claim 1 , wherein the specific time unit corresponds to a CSI reference resource.

4. The method of claim 1 , wherein the particular PMI corresponds to the particular time unit.

5. The method of claim 1 , wherein the particular time unit corresponds to a particular offset from a time unit in which the CSI report is transmitted.

6. The method of claim 1 , wherein a first time unit of the plurality of time units within a configured window corresponds to a CSI reference resource.

7. The method of claim 1 , wherein a time duration of the time unit is equal to a period of a CSI-RS (reference signal).

8. The method of claim 1 , wherein the multiple time units have the same time duration.

9. A terminal in a wireless communication system, the terminal comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: receiving one or more channel state information-reference signals (CSI-RS) from a network via the one or more transceivers; Calculating a channel quality indicator (CQI) based on a specific precoding matrix indicator (PMI), the specific PMI being one of a plurality of precoding matrix indicators (PMIs) corresponding to a plurality of time units, respectively; and transmitting a channel state information (CSI) report to the network via the one or more transceivers, the CSI report including codebook information corresponding to the one CQI and the plurality of PMIs; A terminal, wherein the one CQI is associated with a specific time unit, which is one of the plurality of time units, and the specific PMI.

10. 1. A method performed by a base station in a wireless communication system, the method comprising: transmitting one or more channel state information-reference signals (CSI-RS) to a terminal; receiving a CSI report from the terminal, the CSI report including codebook information corresponding to a channel quality indicator (CQI) and a plurality of precoding matrix indicators (PMIs); The one CQI is calculated based on a specific PMI which is one of a plurality of PMIs corresponding to a plurality of time units, respectively; The method, wherein the one CQI is associated with a particular time unit, the particular time unit being one of the plurality of time units, and the particular PMI.

11. A base station in a wireless communication system, the base station comprising: one or more transceivers; one or more processors coupled to the one or more transceivers; The one or more processors: Transmitting one or more channel state information-reference signals (CSI-RS) to a terminal via the one or more transceivers; configured to receive, from the terminal via the one or more transceivers, a CSI report including codebook information corresponding to a channel quality indicator (CQI) and a plurality of precoding matrix indicators (PMIs); The one CQI is calculated based on a specific PMI which is one of a plurality of PMIs corresponding to a plurality of time units, respectively; A base station, wherein the one CQI is associated with a specific time unit, which is one of the plurality of time units, and the specific PMI.

12. 1. A processing device configured to control a terminal in a wireless communication system, the processing device comprising: one or more processors; and one or more computer memories operatively coupled to said one or more processors and storing instructions for performing the method of any one of claims 1 to 7 when executed by said one or more processors.

13. One or more non-transitory computer-readable media storing one or more instructions, A computer readable medium, the one or more instructions being executed by one or more processors to control a device in a wireless communication system to perform the method of any one of claims 1 to 7.

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