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

Abstract

To provide a method and apparatus for transmitting or receiving channel state information in a wireless communication system.SOLUTION: According to an embodiment of the present disclosure, a method performed by a terminal in a wireless communication system includes receiving one or more channel state information-reference signals (CSI-RSs) from a network, calculating one channel quality indicator (CQI) based on a specific precoding matrix indicator (PMI) which is one of a plurality of pMIS respectively corresponding to a plurality of time units, and transmitting a CSI report including the one CQI and codebook information corresponding to the plurality of pMIS to the network. The one CQI may be associated with a specific time unit which is one of the plurality of time units and the specific PMI.SELECTED DRAWING: Figure 8

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 include data services, and the explosive growth in traffic is causing resource shortages. Users are also demanding faster services, so there is a demand for more advanced mobile communication systems.

[0003] Requirements for next-generation mobile communication systems include the ability to handle large and explosive data traffic, a dramatic increase in transmission rate per user, the ability to handle a significantly increased number of connected devices, extremely low end-to-end latency, and high energy efficiency. To achieve these goals, various technologies are being researched, including dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), super wideband support, and device networking. 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 solved 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-RSs) 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 PMIs corresponding to a plurality of time units; and transmitting a CSI report to the network, the CQI including the specific CQI and codebook information corresponding to the plurality of PMIs, wherein the one CQI may be associated with the specific time unit, the specific time unit being one of 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: transmitting one or more channel state information-reference signals (CSI-RSs) to a terminal; and receiving a CSI report from the terminal, the CSI report 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. [Effects 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 those having ordinary skill in the art to which the present disclosure pertains from the following description. [Brief explanation 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. [Figure 2] 1 illustrates a frame structure in a wireless communication system to which the present disclosure is applicable. [Figure 3] 1 illustrates an example of a resource grid in a wireless communication system to which the present disclosure is applicable. [Figure 4] 1 illustrates an example of a physical resource block in a wireless communication system to which the present disclosure is applicable. [Figure 5] 1 illustrates an example 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 signal transmission / reception method using the physical channels. [Figure 7] 1 illustrates a multiple TRP transmission method in a wireless communication system to which the present disclosure is applicable. [Figure 8]FIG. 10 is a diagram illustrating an example of a CSI report transmission method of a terminal according to the present disclosure. [Figure 9] FIG. 10 is a diagram illustrating an example of a CSI report reception method of a base station according to the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating an example of a CSI reference resource and a CSI reporting time unit according to the present disclosure. [Figure 11] FIG. 10 is a diagram illustrating an example of a CSI reference resource and a CSI reporting time unit according to the present disclosure. [Figure 12] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present disclosure will be described in detail below 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 represent the only embodiments 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 will be 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 shown in block diagram form, focusing on the core functions of each structure and device.

[0016] In this disclosure, when a component is "coupled," "coupled," or "connected" to another component, this may include a direct connection, as well as an indirect connection where there is another component between them. Also, in this disclosure, the terms "comprise" or "have" 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, not 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 forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. The term "and / or" used in this disclosure means that one of the associated listed items may be used, or that any and all possible combinations of two or more of them may be used. 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 a wireless communication system, and operations performed in a wireless communication network may be performed in the 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 the process in which a terminal coupled to the wireless network transmits or receives signals to or from the network or between terminals.

[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] Hereinafter, downlink (DL) refers to communication from a base station to a terminal, and uplink (UL) refers to communication from a terminal to a base station. In the downlink, a transmitter may be part of the base station, and a receiver may be part of the terminal. In the uplink, a transmitter may be part of the terminal, and a receiver may be 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, evolved-Node B (eNB), Next Generation Node B (gNB), base transceiver system (BTS), access point (AP), network (5G network), artificial intelligence (AI) system / module, road side unit (RSU), robot, unmanned aerial vehicle (UAV), augmented reality (AR) device, virtual reality (VR) device, etc. Furthermore, a terminal may be fixed or mobile, and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, RSU (road side unit), robot, AI (Artificial Intelligence) module, drone (UAV: Unmanned Aerial Vehicle), AR (Augmented Reality) device, VR (Virtual Reality) 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), and 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 (LTE) is a part of E-UMTS (Evolved UMTS) that uses E-UTRA, and LTE-Advanced (LTE-A) / 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, the following description will be based on a 3GPP communication system (e.g., LTE-A, NR), but the technical concept of the present disclosure is not limited thereto. LTE refers to technology from 3GPP Technical Specification (TS) 36.xxx Release 8 onward. Specifically, LTE technology from 3GPP TS 36.xxx Release 10 onward is called LTE-A, and LTE technology from 3GPP TS 36.xxx Release 13 onward is called LTE-A pro. 3GPP NR refers to technology from TS 38.xxx Release 15 onward. LTE / NR may be referred to as a 3GPP system. "xxx" refers to the standard document detail number. LTE / NR may be referred to as a 3GPP system. For background technology, terms, abbreviations, etc. used in the description of the present disclosure, please refer to the 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 terminology abbreviations that may be used in this disclosure are defined as follows:

[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 greater communication capacity, there is a growing need for improved mobile broadband communication compared to existing radio access technologies (RATs). Massive Machine Type Communications (MTC), which connects multiple devices and objects to provide a variety of services anytime, anywhere, is also one of the key issues being considered for next-generation communications. In addition, communication system designs that take into account reliability- and latency-sensitive services / terminals are also being discussed. Thus, the introduction of next-generation RATs that take into account technologies such as enhanced mobile broadband communication (eMBB), massive MTC (MMTC), and ultra-reliable and low latency communication (URLLC) is being discussed. For convenience, these technologies will be referred to as NR in this disclosure. NR is an example of a 5G RAT.

[0062] New RAT systems, including NR, use an OFDM transmission scheme or a similar transmission scheme. A new RAT system may follow OFDM parameters different from those of LTE. Alternatively, a 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 within 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 a control plane (RRC) protocol termination for UEs. 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] An NR system can support multiple numerologies. Here, a numerology may be defined by subcarrier spacing and cyclic prefix (CP) overhead. In this case, multiple subcarrier spacings may be derived by scaling the base (reference) subcarrier spacing by an integer N (or μ). Furthermore, even if it is assumed that very low subcarrier spacings are not used at very high carrier frequencies, the numerology used may be selected independently of the frequency band. Furthermore, an NR system may support various frame structures with multiple numerologies.

[0068] The following describes OFDM numerologies and frame structures that can be considered in an NR system. A number of OFDM numerologies supported in an 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, a 15 kHz SCS supports wide areas in traditional cellular bands, a 30 kHz / 60 kHz SCS supports dense urban areas, lower latency, and wider carrier bandwidths, and a 60 kHz or higher SCS supports bandwidths greater than 24.25 GHz to overcome phase noise. NR frequency bands are defined as two types of frequency ranges (FR1 and FR2). FR1 and FR2 may be configured as shown in Table 2 below. FR2 can also refer to millimeter wave (mmW).

[0071] [Table 2]

[0072] In relation to the frame structure in an NR system, the size of the various fields in the time domain is T c =1 / (Δf max N f ) where Δf max =480 10 3 Hz and N f= 4096. Downlink and uplink transmission is T f =1 / (Δf max N f / 100)·T c The radio frame is organized into radio frames each having a duration of T = 10 ms. 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. In addition, transmission from a terminal in uplink frame number i begins 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 an 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 shows an example where μ=2 (SCS is 60 kHz). Referring to Table 3, one subframe can include four slots. The {1, 2, 4} slots shown in FIG. 2 are 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 fewer symbols. Regarding physical resources in an NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, and the like may be considered. The physical resources that can be considered in an NR system will now be described in detail. First, regarding antenna ports, the antenna ports are defined so that the channel on which symbols on an antenna port are carried can be inferred from the channel on which other symbols on the same antenna port are carried. Two antenna ports are said to be in a QC / QCL (quasi co-located) relationship if the large-scale properties of the channel through which symbols on one antenna port are carried can be inferred from the channel through which symbols on the other antenna port are carried. Here, the large-scale properties include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing. Figure 3 illustrates an example of 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 RBIt consists of subcarriers, and one subframe is 14.2 μ In the NR system, a transmitted signal is composed of N OFDM symbols. 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 not only depending on the numerology but also between the uplink and downlink. In this case, one resource grid may be configured 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. JPEG2026034564000006.jpg617, where k=0,...,N RB μ N sc RB -1 is the index in the frequency domain, JPEG2026034564000007.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. JPEG2026034564000008.jpg617 is a complex value JPEG2026034564000009.jpg911. If there is no risk of confusion or if a specific antenna port or numerology is not specified, the indices p and μ may be dropped, so that the complex value is JPEG2026034564000010.jpg1130. Also, a resource block (RB) is a set of 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'. In the frequency domain, common resource block number n CRB μThe relationship between the resource elements (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 so that k=0 corresponds to the subcarrier centered at point A. The physical resource blocks are numbered from 0 to N within the bandwidth part (BWP). BWP,i size,μ Physical resource block n in BWP i is numbered from -1 to i. 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 multiple 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 wave 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 wave can include up to N (e.g., 5) BWPs. Data communication is performed using 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 on such a wideband CC keeps the radio frequency (RF) chip for the entire CC on at all times, battery consumption may increase. Considering various application cases (e.g., eMBB, URLLC, MMTc, V2X, etc.) operating within a single wideband CC, different numerologies (e.g., subcarrier spacing, etc.) may be supported for each frequency band within the CC. Each terminal may have different capabilities for maximum bandwidth. In consideration of this, a base station may instruct a terminal to operate only with a portion of the bandwidth of a wideband CC, rather than the entire bandwidth. For convenience, this portion of the bandwidth is defined as a bandwidth part (BWP). A BWP may consist of contiguous RBs on the frequency axis and may correspond to one numerology (e.g., subcarrier spacing, CP length, slot / minislot duration).

[0089] Meanwhile, a base station can configure multiple BWPs within one CC configured for a terminal. For example, a BWP occupying a relatively small frequency region can be configured in a PDCCH monitoring slot, and the PDSCH indicated by the PDCCH can be scheduled on a larger BWP. Alternatively, if UEs are concentrated in a specific BWP, other BWPs can be configured for some terminals for load balancing. Alternatively, both BWPs can be configured within the same slot by excluding a portion of the spectrum from the entire bandwidth, taking into account frequency domain inter-cell interference cancellation between neighboring cells. That is, a base station can configure at least one DL / UL BWP for a terminal associated with a wideband CC. The base station can activate at least one DL / UL BWP configured at a specific time (through L1 signaling, MAC Control Element (CE), RRC signaling, etc.). In addition, the base station can instruct switching to another configured DL / UL BWP (by L1 signaling, MAC CE, RRC signaling, etc.). Alternatively, 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 situations where the UE is performing an initial access procedure or before an RRC connection is set up, the UE may not be able to receive the configuration for the DL / UL BWP. Therefore, the DL / UL BWP assumed by the UE in such situations is defined as the initially active DL / UL BWP.

[0090] FIG. 6 illustrates physical channels used in a wireless communication system to which the present disclosure is applicable, 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 exchanged 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 exchanged.

[0092] When a terminal is powered on or newly enters a cell, it performs an initial cell search, such as synchronizing with a base station (S601). To do this, 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 acquire information such as a cell identifier (ID). Then, the terminal receives a physical broadcast channel (PBCH) from the base station to acquire broadcast information within the cell. Meanwhile, the terminal can receive a downlink reference signal (DL RS) during the initial cell search phase to check the downlink channel status.

[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, thereby obtaining more specific system information (S602).

[0094] Meanwhile, when the terminal first connects to the base station or when there are no radio resources for signal transmission, the terminal can perform a random access procedure (RACH: Random Access Procedure) with the base station (steps S603 to S606). To this end, the terminal transmits a specific sequence as a preamble on a physical random access channel (PRACH: Physical Random Access Channel) (S603 and S605) and can 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-described procedures, the UE 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 UE receives downlink control information (DCI) through the PDCCH. Here, DCI includes control information such as resource allocation information for the UE, and its format varies depending on its purpose.

[0096] Meanwhile, control information that a terminal transmits to a base station on the 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 on 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 may 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., Modulation Coding and Scheme (MCS), New Data Indicator (NDI), Redundancy Version (RV), etc.), hybrid-automatic repeat and request (HARQ)-related information (e.g., process number, Downlink Assignment Index (DAI), PDSCH-HARQ feedback timing, etc.), multiple antenna-related information (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), and power control information (e.g., PUSCH power control, etc.), and 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 CRC (cyclic redundancy check) scrambled by a Cell Radio Network Temporary Identifier (C-RNTI), a Configured Scheduling RNTI (CS-RNTI), or a Modulation Coding Scheme Cell RNTI (MCS-C-RNTI) before being transmitted. DCI format 0_1 ​​is used to schedule one or more PUSCHs in one cell or to indicate configured grant (CG) downlink feedback information to a terminal. The information included in DCI format 0_1 ​​is CRC scrambled by a C-RNTI, a CS-RNTI, a Semi-Persistent CSI RNTI (SP-CSI-RNTI), or a MCS-C-RNTI before being transmitted. DCI format 0_2 is used for scheduling a PUSCH in one cell.The information included in DCI format 0_2 is CRC-scrambled by the C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI and then transmitted. Next, 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 DCI format may be predefined.

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

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

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

[0103] Multi-TRP related operations

[0104] The Coordinated Multipoint (CoMP) technique is a method of effectively controlling interference by having multiple base stations mutually exchange (e.g., using the X2 interface) or utilize channel information (e.g., RI / CQI / PMI / LI (layer indicator)) fed back from terminals and then transmit coordinated data to the terminal. Depending on the method used, CoMP can be categorized 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 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 UE in one DCI, and it can 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, which has the effect of increasing the probability of data reception by 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 PUSCHs (or PUCCHs) scheduled by DCIs received in different control resource sets (CORESETs) (or CORESETs belonging to different CORESET groups) as PUSCHs (or PUCCHs) transmitted in different TRPs or as PDSCHs (or PDCCHs) in different TRPs. In addition, the schemes for UL transmissions (e.g., PUSCHs / PUCCHs) transmitted in different TRPs, which will be described later, can also be applied to UL transmissions (e.g., PUSCHs / PUCCHs) transmitted in different panels belonging to the same TRP.

[0109] Hereinafter, 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 resource, and transmits data using different layers (i.e., different DMRS ports) using different DMRS (Demodulation Multiplexing Reference Signal) ports between the TPs.

[0111] The TP transmits data scheduling information via DCI to the UE receiving the NCJT. A scheme in which each TP participating in the NCJT transmits scheduling information for its own transmission data via DCI is called 'multi-DCI-based NCJT'. N TPs participating in NCJT transmission each transmit DL grant DCI and PDSCH to the UE, so the UE receives N DCIs and N PDSCHs from the N TPs. In contrast, a scheme 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) via a single DCI is called 'single DCI-based NCJT'. In this case, N TPs transmit one PDSCH, but each TP transmits only some of the multiple layers that make up one PDSCH. For example, if four-layer data is being transmitted, TP1 transmits two layers and TP2 transmits the remaining two 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, we will explain the 'single DCI-based MTRP scheme'. MTRP jointly transmits a common PDSCH in a coordinated manner, and each TRP participating in the coordinated transmission spatially divides the PDSCH and transmits it in different layers (i.e., different DMRS ports) using the same time-frequency resource. In this case, scheduling information for the PDSCH is indicated to the UE by a single DCI, which indicates which DMRS (group) port uses which QCL RS and QCL type information (this differs from the existing DCI, which indicates the QCL RS and type commonly applied to all DMRS ports). That is, M TCI states are indicated in a Transmission Configuration Indicator (TCI) field in the DCI (e.g., M=2 in the case of two TRPs in coordinated transmission), and the QCL RS and type may be indicated using different M TCI states for each of the M DMRS port groups. Also, DMRS port information may be indicated using a new DMRS table.

[0114] Next, a 'multiple DCI-based MTRP scheme' will be described. MTRP transmits different DCIs and PDSCHs, and these PDSCHs are transmitted overlapping (partially or completely) with each other on frequency-time resources. These PDSCHs may be scrambled with different scrambling identifiers, and the DCIs may be transmitted by coresets belonging to different coreset groups. (Here, coreset groups may be identified by an index defined in the coreset configuration 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 a coreset, it can be interpreted 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 vary depending on whether the MTRP scheme is single DCI-based or multiple DCI-based (since the CRS patterns are different).

[0116] Hereinafter, a CORESET group identifier (group ID) described / mentioned in this disclosure may refer to an index / identification information (e.g., ID) for distinguishing a CORESET for each TRP / panel. 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, a CORESET group ID may be specific index information defined in a CORESET 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 a CORESET group ID may refer to an index / identification information / designator for distinguishing / identifying CORESETs set in / 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 in / 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 in / associated with each TRP / panel, may be set / instructed to a 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), etc. 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 units of the CORESET group.And / or, it may be configured / instructed that 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) are separately managed / controlled for each TRP / panel (i.e., for each TRP / panel belonging to the same CORESET group) in the CORESET group unit. And / or, HARQ A / N (process / retransmission) for PDSCH / PUSCH, etc. scheduled for each TRP / panel (i.e., for each TRP / panel belonging to the same CORESET group) may be managed.

[0117] Below, we will explain the partially overlapped NCJP.

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

[0119] Below, we will explain a method for improving reliability in multiple (Multi-TRP) systems.

[0120] The following two methods can be considered as transmission and reception methods for improving reliability using transmission with multiple TRPs.

[0121] FIG. 7 illustrates a multiple 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 may refer to a predetermined layer set consisting of one or more layers. In this case, the number of layers increases the amount of transmission resources, which has the advantage of allowing robust channel coding with a low code rate to be used for the TB. In addition, since the channels are different from the multiple TRPs, it is possible to expect improved reliability of the received signal based on diversity gain.

[0123] FIG. 7(b) shows an example 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 identical. That is, CW #1 and CW #2 are obtained by converting the same TB into different CWs through channel coding, etc., using different TRPs. Therefore, this can be considered an example of repeated transmission of the same TB. Compared to FIG. 7(a), FIG. 7(b) may have a disadvantage in that the code rate corresponding to the TB is higher. However, it has an advantage in that the code rate can be adjusted by specifying different redundancy version (RV) 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] Furthermore, although the above content related to multiple TRPs has been described based on an SDM (spatial division multiplexing) scheme using different layers, it goes without saying that this may also be extended and applied to an FDM (frequency division multiplexing) scheme based on different frequency domain resources (e.g., RB / PRB (set), etc.) and / or a TDM (time division multiplexing) scheme based on different time domain resources (e.g., slots, symbols, sub-symbols, etc.).

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

[0127] 1) Scheme 1 (SDM): Time and frequency resource allocation overlap, and n (n <= Ns) TCI states are allocated within 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, and each layer or set of layers is 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's 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, and each layer or set of layers is 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, and 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 indices is transmitted on one layer, or the same TB having multiple DMRS ports associated one-to-one with multiple TCI state indices is transmitted on one layer.

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

[0137] 2) Method 2 (FDM): Frequency resource allocation does not overlap, and n (n <= Nf) TCI states are allocated within 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, and 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 is non-overlapping, and n (n<=Nt1) TCI states are allocated within 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] - The RV / TCI may be the same or different at different transmission occasions.

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

[0150] Each transmission occasion of the TB has one TCI and one RV.

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

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

[0153] The MTRP URLLC will be explained below.

[0154] In the present disclosure, DL MTRP URLLC refers to multiple TRPs transmitting the same data (e.g., the same TB) / DCI using different layer / time / frequency resources. For example, TRP 1 transmits the same data / DCI on resource 1, and TRP 2 transmits the same data / DCI on resource 2. A UE configured with the DL MTRP-URLLC transmission scheme receives the same data / DCI using different layer / time / frequency resources. In this case, the UE is configured by the base station with the QCL RS / type (i.e., DL TCI state) to use on the layer / time / frequency resource receiving the same data / DCI. For example, if the same data / DCI is received on resource 1 and resource 2, the DL TCI state to be used on resource 1 and the DL TCI state to be used on resource 2 may be configured. Since the UE receives the same data / DCI on 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 refers to multiple TRPs receiving 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 using resource 1, and TRP 2 receives the same data / DCI from the UE using resource 2. The received data / DCI is then shared via a connected backhaul link between the TRPs. A UE configured with the UL MTRP-URLLC transmission scheme transmits the same data / UCI using different layer / time / frequency resources. In this case, the base station configures the UE with the Tx beam and Tx power (i.e., UL TCI state) to use on the layer / time / frequency resource for transmitting the same data / UCI. For example, if the same data / UCI is transmitted on resource 1 and resource 2, the UL TCI state used on resource 1 and the UL TCI state used on resource 2 may be configured. Such UL MTRP URLLC may be applied to PUSCH / PUCCH.

[0156] In addition, in this 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 DL, it can mean estimating a channel from a DMRS using a QCL type and QCL RS indicated by the TCI state in that frequency / time / space resource (layer) and receiving / demodulating data / DCI based on the estimated channel. In UL, it can mean transmitting / modulating DMRS and data / UCI using a Tx beam and / or power indicated by the TCI state in that frequency / time / space resource.

[0157] Here, the UL TCI state includes Tx beam and / or Tx power information of the UE, and spatial relation info, etc., may be configured in the UE by another parameter instead of the TCI state. The UL TCI state may be directly indicated by the UL grant DCI, or may represent spatial relation info of the SRS resource indicated by the sounding resource indicator (SRI) field of the UL grant DCI. Alternatively, it may represent an open-loop (OL) transmit power control parameter (OL Tx power control parameter) linked to the 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 the 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 different data (e.g., different TBs) are transmitted by multiple TRPs using different layers / time / frequencies. A UE configured for MTRP-eMBB transmission assumes that various TCI states are indicated by DCIs and that the data received using the QCL RSs for each TCI state are different from each other.

[0160] Meanwhile, the UE can determine whether it is MTRP URLLC transmission / reception or MTRP eMBB transmission / reception by separately using the RNTI for MTRP-URLLC and the RNTI for MTRP-eMBB. That is, if CRC masking of DCI is performed using the RNTI for URLLC, the UE determines it as URLLC transmission, and if CRC masking of DCI is performed using the RNTI for eMBB, the UE determines it as eMBB transmission. Alternatively, the base station can configure the UE for MTRP URLLC transmission / reception or TRP eMBB transmission / reception using separate new signaling.

[0161] In the description of this disclosure, for convenience of explanation, cooperative transmission / reception between two TRPs is assumed. However, the method proposed in this disclosure may be extended to a multi-TRP environment with three or more TRPs, and may also be extended to a multi-panel environment (i.e., a TRP corresponds to a panel). Furthermore, different TRPs may be recognized as different TCI states by the 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 this disclosure may be used in a situation where MTRPs cooperatively transmit PDCCHs (repeatedly transmit the same PDCCH or transmit it separately).The method proposed in this disclosure may also be used in a situation where MTRPs cooperatively transmit PDSCHs or cooperatively receive PUSCHs / PUCCHs.

[0163] Furthermore, in the present disclosure, the term "multiple base stations (i.e., MTRPs) repeatedly transmitting the same PDCCH" may mean that the same DCI is transmitted using multiple PDCCH candidates, or may mean that multiple base stations repeatedly transmit the same DCI. Here, the term "same DCI" may refer to two DCIs having the same DCI format / size / payload. Alternatively, two DCIs may be considered to be the same if they have different payloads but the same scheduling results. For example, the time domain resource allocation (TDRA) field of a DCI determines the slot / symbol position of data and the slot / symbol position of A / N (ACK / NACK) relative to the time point at which the DCI is received. However, if a DCI received at time n and a DCI received at time n+1 indicate the same scheduling results to a UE, the TDRA fields of the two DCIs will differ, resulting in different DCI payloads. 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 two DCIs have different payloads and not identical scheduling results, they can be considered to be the same DCI if the scheduling result of one DCI is a subset of the scheduling result of the other DCI. For example, when the same data is time-division multiplexed and transmitted N times, DCI 1 received before the first data indicates N data repetitions, and DCI 2 received after the first data but before the second data indicates N-1 data repetitions. The scheduling data of DCI 2 is a subset of the scheduling data of DCI 1, and since both DCIs are scheduling for the same data, they can also be considered to be the same DCI in this case.

[0164] In addition, in the present disclosure, when multiple base stations (i.e., MTRPs) transmit the same PDCCH in separate ways, it means that one DCI is transmitted using one PDCCH candidate, with TRP1 transmitting some of the resources defined by the PDCCH candidate and TRP2 transmitting the remaining resources. For example, when TRP1 and TRP2 separately transmit PDCCH candidates corresponding to aggregation level m1+m2, the PDCCH candidates are separated into PDCCH candidate 1 corresponding to aggregation level m1 and PDCCH candidate 2 corresponding to aggregation level m2, and TRP1 can transmit PDCCH candidate 1 and TRP2 can transmit PDCCH candidate 2 using 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] Furthermore, in the present disclosure, a UE repeatedly transmitting the same PUSCH to be received by multiple base stations (i.e., MTRPs) may mean that the UE transmits the same data on multiple PUSCHs. In this case, each PUSCH may be optimized for a UL channel of a different TRP. For example, when a UE repeatedly transmits the same data on PUSCHs 1 and 2, PUSCH 1 is transmitted using UL TCI state 1 for TRP 1, and link adaptation such as precoder / MCS may be scheduled / applied with values ​​optimized for the channel of TRP 1. PUSCH 2 is transmitted using UL TCI state 2 for TRP 2, and link adaptation such as precoder / MCS may be scheduled / applied with values ​​optimized for the channel of TRP 2. In this case, the repeatedly transmitted PUSCHs 1 and 2 may be transmitted at different times and may be TDM, FDM, or SDM.

[0166] Furthermore, in the present disclosure, the term "a UE transmitting the same PUSCH in separate channels for reception by multiple base stations (i.e., MTRPs)" may refer to a UE transmitting one piece of data over one PUSCH, but dividing the resources allocated to the PUSCH and optimizing the data transmission to UL channels of different TRPs. For example, when a UE transmits the same data over a 10-symbol PUSCH, the UE transmits the data using UL TCI state 1 for TRP 1 over the first five symbols, and link adaptation such as precoder / MCS may be scheduled / applied with values ​​optimized for the channel of TRP 1. The remaining data over the remaining five symbols may be transmitted using UL TCI state 2 for TRP 2, 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 transmissions toward TRP 1 and TRP 2 are TDM-based, but transmissions may also be performed using FDM / SDM.

[0167] Similarly to the PUSCH transmission described above, the UE can 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 on which a channel is transmitted / received or a candidate resource unit on which a channel can be transmitted / received. For example, when multiple channels are transmitted in a TDM manner, a TO may refer to each channel that is transmitted / can 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 / can 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 / can 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 in one TO, and the receiving end may receive multiple TOs to increase the success rate of reception.

[0171] The above-described single DCI (S-DCI)-based multi-TB PUSCH / PDSCH scheduling scheme may be applied, for example, when one DCI simultaneously schedules multiple PUSCHs / PDSCHs in an ultra-high frequency band (above 5.26 GHz). For example, the time-domain resource allocation (TDRA) field of a DCI scheduling a PUSCH may indicate multiple TDRAs (or TOs) at once, and different TBs may be transmitted via the 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. Furthermore, the NDI and RV for each TB may be indicated individually / independently 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, values ​​that increase sequentially in the order of TOs based on the initial TO may be applied.

[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 / towards TRP1 and TRP2, respectively. In addition, the base station may indicate SRS resources for each SRS resource set using two SRI fields included in one DCI, and indicate up to two PC parameter sets.

[0173] For example, the first SRI field may indicate the SRS resources and PC parameter set defined in SRS resource set 0, and the second SRI field may indicate the SRS resources and PC parameter set defined in SRS resource set 1. The UE may be indicated the UL Tx port, PC parameter set, and UL beam / QCL information for TRP1 in the first SRI field, whereby the UE performs PUSCH transmission in a TO corresponding to SRS resource set 0. Similarly, the UE may be indicated the UL Tx port, PC parameter set, and UL beam / QCL information for TRP2 in the second SRI field, whereby the UE 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 into two fields so that TPMI, PTRS, and TPC-related fields can also be indicated for each TRP.

[0175] Furthermore, 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, code point "0" in the SRS resource set indication field may be set / defined to indicate the first SRS resource set, and code point "01" may be set / defined to indicate the second SRS resource set. When 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, code point "10" may be set / defined to indicate (first SRS resource set, second SRS resource set), and code point "11" may be set / defined to indicate (second SRS resource set, first SRS resource set). When code point "10" or "11" is indicated, M-TRP PUSCH transmission may be performed in the indicated order of SRS resource set pairs. When code point "10" is indicated, the first SRS resource set corresponds to the first PUSCH TO, and when code point "11" is indicated, the second SRS resource set corresponds to the first PUSCH TO.

[0177] Furthermore, a single PUCCH resource-based M-TRP PUCCH repetition 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 (for FR1, activate / configure two PC parameter sets) for a single PUCCH resource in the UE. When UL UCI is transmitted using the PUCCH resource, each piece of spatial relation info is used to indicate spatial relation info for TRP1 and TRP2, respectively, to the UE. For example, the value indicated in the first piece of spatial relation info indicates the Tx beam / PC parameters for TRP1 to the UE, and the UE uses the information to transmit PUCCH at the TO corresponding to TRP1. Similarly, the value indicated in the second spatial relation info indicates to the terminal the Tx beam / PC parameters toward TRP2, and the terminal uses this 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 pieces of spatial relation info can be configured in a PUCCH resource. That is, when power control (PC) parameters such as PLRS, Alpha, P0, and Closed loop index are configured in each piece of spatial relation info, a 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 pieces of spatial relation info. As a result, the terminal transmits a UCI (i.e., CSI, ACK / NACK, SR, etc.) PUCCH using the first spatial relation info in the first TO, and transmits a same-UCI PUCCH using the second spatial relation info in the second TO. In the present disclosure, a PUCCH resource configured with two pieces of spatial relation info may be referred to as an M-TRP PUCCH resource, and a PUCCH resource configured with one piece of spatial relation info 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, a DL DCI (e.g., DCI format 1_1 / 1_2, etc.) may indicate both the DL TCI status and the UL TCI status. Alternatively, a DL DCI may indicate only the UL TCI status without indicating the DL TCI status. Thus, the schemes previously used for UL beam and power control (PC) configuration 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 UE simultaneously transmits multiple channels (CHs) / reference signals (RSs) of the same type, and a new method in which a UE simultaneously transmits multiple CHs / RSs of different types are being discussed. Existing methods limit a UE's ability to transmit multiple CHs / RSs at one time point (or one time unit). For example, while existing methods support a UE simultaneously transmitting multiple SRS resources belonging to different SRS resource sets for uplink beam measurement, they do not support simultaneously transmitting multiple different PUSCHs. Therefore, to alleviate the above limitations and support more advanced UE operation, a method in which a UE simultaneously transmits multiple CHs / RSs using multiple transmission elements is being discussed.

[0182] For example, according to the present disclosure, a terminal can simultaneously perform uplink transmissions to multiple transmission targets using multiple transmission elements. Furthermore, a base station can simultaneously receive uplink transmissions transmitted from the terminal using multiple transmission elements via the multiple transmission targets. For example, the transmission elements of the 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, the antenna group / panel may be indicated / identified by the RS (candidate) set. For example, the transmission targets of the uplink transmissions from the terminal may correspond to a TRP or a cell, and one TRP / cell may correspond to one CORESET group / pool. That is, the TRP / cell may be indicated / identified by the 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 names of such transmission schemes, the units of transmission elements, and / or the unit examples of transmission targets.

[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. 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). 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-related 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-related 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 the 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 should be transmitted using STxMP, a single panel, or M-TRP PUSCH repetition. In this case, the terminal should have STxMP-related capability, and the STxMP mode should be enabled in advance 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 high-speed terminals. For example, various examples for applying a time-domain compression window to PMI included in CSI will be described below.

[0189] In existing wireless communication systems, 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. This disclosure describes a scheme for compressing PMI for multiple time units in the time domain and reporting it as one codebook (i.e., included in one CSI report).

[0190] For example, the present disclosure may include specific examples for the number of time units (or time instances), the interval between time units, the position of a CSI reference resource, the window (or duration) of 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 and time units for channel measurement resources (CMRs) / interference measurement resources (IMRs). The present disclosure may include examples for criteria for time unit offsets.

[0191] FIG. 8 is a diagram illustrating 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 into or include the meaning of a precoding matrix indicated by the PMI.

[0195] One CQI may be associated with a specific time unit among multiple time units. Also, one CQI may be associated with a specific PMI among multiple 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 specific 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, the first time unit of the plurality of time units within the set window may correspond to the CSI reference resource.

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

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

[0201] For example, the duration of one time unit may be the same as the CSI-RS period. Also, multiple time units may have the same time duration. That is, the duration of a first time unit may be the same as the duration of a second time unit. This allows multiple time instances to be evenly spaced in the time domain.

[0202] In step S830, the terminal may transmit a CSI report including one CQI and codebook information corresponding to multiple 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 one CQI and codebook information. A CSI report may be transmitted in one reporting instance or in multiple reporting instances (i.e., information included in one CSI report is transmitted at different times / channels).

[0205] FIG. 9 is a diagram illustrating an example of a CSI report reception method in 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 from the terminal, the CSI report including one CQI and codebook information corresponding to multiple PMIs. The one CQI may be calculated based on a specific PMI, which is one of multiple PMIs corresponding to multiple 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, redundant description will be omitted.

[0209] 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 below.

[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, and terminal reporting of time-domain channel properties such as Doppler shift or Doppler spread using TRS may be considered. 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) that is vulnerable to channel aging. This allows the base station to predict time-varying channel directions and schedule better MCS and precoders. Meanwhile, calculating and reporting Doppler information using TRS in addition to existing CSI can help the terminal to compensate for outdated CSI using the Doppler information. This allows the base station to predict time-varying channel directions and schedule better MCS and precoders.

[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 refinement.

[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 can measure the latest CMR / IMR no later than the CSI reference resource, so a single measurement can 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 multiple measurements are used to estimate the channel on the CSI reference resource may vary depending on the implementation of the terminal. In this way, for an unrestricted measurement configuration (i.e., with restrictions disabled), 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 may be required on the terminal side for Type II codebook improvement including TD compression. Also, if a time restriction for channel measurements (e.g., the timeRestrictionForChannelMeasurements parameter) is not configured, 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., the timeRestrictionForChannelMeasurements parameter) is configured, the terminal calculates CSI using a single channel / interference measurement, so the improved codebook including TD compression may not be available.

[0219] Whether multiple channel measurements are possible depends not only on the time-domain measurement limitations as described above, but also on the periodicity of the CMR / IMR. In the case of aperiodic (AP) CMR / IMR, only one CMR / IMR exists without periodicity, so only a single measurement is possible. Periodic (P) / semi-static (SP) CMR / IMR provides multiple opportunities for the UE to measure the channel / interference. For example, assuming a minimum period of four slots, it is necessary to investigate whether sufficiently frequent measurement instances are provided for high-speed UEs. If the measurement instances are too sparse, the PMI accuracy may decrease and the quality of TD compression may be poor. Alternatively, if the measurement instances are too dense, the CSI-RS overhead may increase.

[0220] That is, only one CMR / IMR exists for the AP CMR / IMR without periodicity, so only a single measurement is possible. 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 explain the multiple time instances (or time units) represented by the 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 need to be determined / defined.

[0223] 10 and 11 are diagrams illustrating 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 PMI associated with one CQI may be the first / earliest time unit and the corresponding first / earliest PMI in the example of FIG. 10. Alternatively, the time unit and PMI associated with one CQI may be the last time unit and the corresponding last PMI (e.g., the third PMI among three PMIs) in the example of FIG. 11.

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

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

[0227] 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 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 later than the CSI reference resource. ref_rsc+2τ, which may be predicted from a periodic CMR that is not slower than the CSI reference resource. For example, assuming that the CSI reference resource is located in slot l, the UE can calculate the PMI based on the DL channel in slot l+τ. ref_rsc+τ , and PMI based on the DL channel in slot l+2τ ref_rsc+2τ , ... can be calculated.

[0228] This will increase PMI ref_rsc , PMI ref_rsc+τ , PMI ref_rsc+2τ , ... can be compressed by using an improved Type II codebook including TD compression, which can reduce PMI feedback overhead. A codebook including PMI at a future time point relative to the CSI reporting time point (e.g., slot n) is robust to channel aging because it requires the terminal 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 in FIG. 11 shows PMI for multiple time units 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 , which may be predicted from a periodic CMR that is not slower than the CSI reference resource. For example, assuming that the CSI reference resource is located in slot l, the UE can calculate the PMI based on the DL channel in slot l-τ. ref_rsc-τ , and PMI based on the DL channel in slot l-2τ ref_rsc-2τ , ... can be calculated.

[0231] The example of Figure 11 shows that periodic CMR exists with a CSI reference resource, a CSI reference resource -τ, and a 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).

[0232] This will increase PMI ref_rsc , PMI ref_rsc-τ , PMI ref_rsc-2τ , ... can be compressed by using an improved Type II codebook including TD compression, which can 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) can reduce the complexity of 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 than 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 the channel aging effect due to high mobility, a terminal can calculate multiple PMIs for multiple time instances. As the number of time instances associated with a PMI increases, the PMI feedback payload may increase linearly. Even if multiple PMIs share the same spatial domain (SD) basis and / or frequency domain (FD) basis, at least mutually 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 reducing feedback overhead. Considering existing Type II codebooks in which SD basis and FD basis are independently selected based on DFT matrices, 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 or opposite to the moving direction of the terminal, 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 reduction in 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 instance (e.g., CSI reporting window) of the channel 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 configured 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 configured for the terminal by the 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 codebook configuration.

[0243] The number of time instances to be represented by the PMI (i.e., information regarding the number of time instances within a window) may be configured / 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 configured 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 its preferred number of time instances to the base station based on its own speed or Doppler information, and the base station may approve or consider this to select a time instance number value to be finally applied and notify the terminal. Additionally or alternatively, the terminal may also 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 FIGS. 10 and 11) may be configured / instructed to the terminal. The τ value may be configured taking into consideration the time variation of the channel, and for this purpose, the terminal may report its own velocity information, Doppler information (e.g., Doppler shift / Doppler spread), etc. to the base station. Alternatively, the terminal may report its preferred τ value to the base station based on its own velocity or Doppler information, and the base station may approve or consider it to 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, the number of slots, the 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 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 time instances can also be said to be the duration of each time instance. That is, information regarding the interval between time instances or the duration of each time instance may be configured / instructed separately 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 also apply 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 a window, a single CQI may be associated with the first / earliest time unit and its 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 also apply 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 time unit and its corresponding PMI (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 respect to 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 own velocity information, Doppler information (e.g., Doppler shift / Doppler spread), etc. to the base station. Alternatively, the terminal may report its preferred time instance offset to the base station based on its own velocity or Doppler information, and the base station may approve or consider it to select the 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 UE may support only the former capability, another UE may support only the latter capability, and yet another UE may support both the former and latter capabilities. Such UE capabilities may be reported to the network. The former capability does not require channel prediction, making UE implementation simple, while the latter capability requires channel prediction, making UE implementation complex. Specifically, in the latter case, the UE may further report to the network a configurable minimum time instance offset value (i.e., related to the UE's prediction performance) or candidate configurable time instance offset values ​​(i.e., related to the UE's prediction performance). For example, the smaller the minimum time instance offset value, the more predictions must be performed, which may increase the complexity of UE implementation.

[0251] In the above example, the position of the time instances in the time domain (e.g., grid) is defined / set by the number and spacing 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 time instance window may be defined / set as the 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 positions of the time instances in the time domain (e.g., grid). That is, time instances spaced equally apart by the number of time instances within the window may be determined. Alternatively, time instances having the same duration within the window may be determined. For example, if the length of the window is defined as three slots and the number of time instances is three, the time instance grid may be expressed as three consecutive slots. That is, the duration of each time instance may be one slot.

[0253] In this case, if the time instance offset value is given as 0, the final time instance may be determined as 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 changes over time and is predictable, distributing the time instances at equal intervals (or with the same duration) may be inefficient. For example, when N time instances are set, assume that the channel time variation is strong at the beginning (i.e., early time) of the entire time interval represented by the PMI and weak at the end (i.e., late time) of the entire time interval. In this case, the time instances may be arranged more densely (i.e., with closer intervals or shorter durations) at the beginning of the entire time interval and more sparsely (i.e., with wider intervals or longer durations) at the end 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 increased compression ratio and accuracy for TD compression.

[0255] In this way, the time instances within the window may be spaced equally (or have the same duration) or unequal (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 provide the terminal with 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 the 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 TD-compressed codebook may vary depending on the time instances set as above. For example, the fewer the number of time instances for the same window length, the larger the interval between time instances (or the duration of the time instances), or the longer the window length, the more time must be TD-compressed. Appropriate TD basis candidates may vary in these different cases. For example, if TD basis candidates are configured based on a DFT matrix, the DFT matrix may be configured as a function of the number of time instances or the interval between time instances. Furthermore, when the SD / FD / TD basis is linearly combined, the granularity (or the configurable range of the granularity) of the coefficients (e.g., amplitude, phase) applied may also be adjusted. For example, when the number of time instances increases, the number of coefficients may increase. To offset the corresponding increase in overhead, the granularity of the coefficients may also increase, and the number of candidate values ​​that can be represented within the range of coefficient values ​​may decrease. Also, instead of reporting all 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 settable range) for the number of such 0-value 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] In addition, a CMR / IMR measurement restriction period may be determined in association with the PMI time instance. For example, as shown in FIG. 11, if slot l, slot l-τ, and slot l-2τ are set as time instances (or CSI reporting windows) represented by the PMI, the DL channel of slot l may be restricted to be measured using the CMR / IMR present 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 present 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 present before slot l-2τ or slot l-2τ and after slot l-3τ or slot l-3τ (or before slot l-2τ, with no restriction on which time boundary to measure after). With these 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 the position of the CSI reference resource included in the time offset) may be defined / configured based on the CSI reporting time point (e.g., slot n in FIGS. 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 refers to a time interval (or time unit) during which a channel / interference can be measured for CSI calculation, and the CSI reporting window may refer to a time interval (or time unit) corresponding to a channel represented by 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, time instances may exist only at future times relative 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, time instances may exist only at past times relative 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 also set / instruct the terminal to set a time instance offset value (e.g., within the range reported by the terminal) taking into account the reported information from the terminal.

[0266] In the case of AP CSI reporting, values ​​for various information / parameters provided to the terminal described in the above examples may be set / indicated by (both) 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 values ​​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 values ​​for the number of time instances and / or the time instance interval, which affect the amount of CSI calculation. The base station may set / instruct the terminal to the number of time instances and / or the time instance interval (e.g., within a range not exceeding the maximum values) taking into account the maximum values ​​reported by the terminal.

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

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

[0270] General devices to which the present disclosure can be applied

[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 (e.g., 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 flowcharts disclosed in this disclosure. For example, the processor 102 may process information in the memory 104 to generate 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 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 for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 102 and the memory 104 may be part of a communications 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 also be referred to as an RF (Radio Frequency) unit. In the present invention, a wireless device may refer to a communications modem / circuit / chip.

[0274] The second wireless device 200 includes 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 flowcharts disclosed in this disclosure. For example, the processor 202 may process information in the memory 204 to generate 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 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 for implementing the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure. Here, the processor 202 and the memory 204 may be part of a communications modem / circuit / chip designed to implement 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 also be referred to as an RF unit. In the present invention, a wireless device may refer to a communications modem / circuit / chip.

[0275] The hardware elements of the wireless devices 100, 200 are described in more detail below. Without limitation, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, and SDAP). The 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 this disclosure. The 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 this disclosure. The one or more processors 102, 202 can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in this disclosure and provide them to the one or more transceivers 106, 206. 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 flowcharts disclosed in this disclosure.

[0276] The one or more processors 102, 202 may be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be implemented using hardware, firmware, software, or a combination thereof. As an example, the one or more processors 102, 202 may include 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). The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operational flow diagrams disclosed in this 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 flow diagrams disclosed in this disclosure may be embodied by 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 types of data, signals, messages, information, programs, code, instructions, and / or instructions. 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. Additionally, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 via various techniques, such as wired or wireless connections.

[0278] 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 flowcharts of the present disclosure, to one or more other devices. 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 flowcharts of the present disclosure, from one or more other devices. For example, 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, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Also, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, 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, wireless signals / channels, etc., referred to in the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in this disclosure, via the one or more antennas 108, 208. In this 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 user data, control information, wireless signals / channels, etc., from RF band signals to baseband signals for processing using one or more processors 102, 202. The one or more transceivers 106, 206 may convert the user data, control information, wireless 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 embodiments described above are combinations of the components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented without being combined with other components or features. It is also possible to combine some components and / or features to form embodiments of the present disclosure. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components 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 form embodiments, or may be included as new claims 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 reasonable interpretation of the appended 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, as well as non-transitory computer-readable media on which such software or instructions are stored and executable on a device or computer. Instructions usable for programming a processing system to perform features described in this disclosure may be stored on or 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 this disclosure. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, 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. Memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, a non-volatile memory device within the memory, comprises a non-transitory computer-readable storage medium. 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 may include LTE, NR, 6G, and also Narrowband Internet of Things (NB-IoT) for low-power communication. Here, for example, the NB-IoT technology may be an example of a Low Power Wide Area Network (LPWAN) 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 may perform communication based on the LTE-M technology. Here, for example, the LTE-M technology may be an example of an LPWAN technology and may be referred to by various names such as enhanced Machine Type Communication (eMTC). For example, LTE-M technology may be implemented by at least 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 names. Additionally or alternatively, wireless communication technologies implemented in wireless devices 100 and 200 of the present disclosure may include at least one of ZigBee (registered trademark), Bluetooth (registered trademark), and Low Power Wide Area Network (LPWAN), which consider low-power communication, and are not limited to the above names. As an example, ZigBee technology can create personal area networks (PANs) related to small / low-power digital communication based on various standards, such as IEEE 802.15.4, and may be referred to 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 other wireless communication systems in addition to 3GPP LTE / LTE-A and 5G systems.

Claims

1. receiving at least one channel state information-reference signal (CSI-RS) from a network by a terminal; calculating, by the terminal, a channel quality indicator (CQI) based on a specific PMI (precoding matrix indicator), which is one of a plurality of PMIs corresponding to a plurality of slot intervals; transmitting, by the terminal, a CSI report including the one CQI and codebook information corresponding to the plurality of PMIs to the network; The method, wherein the one CQI is associated with the specific PMI and a specific slot of a specific slot interval, the specific slot interval being one of the plurality of slot intervals.

2. the specific slot interval is the first slot interval of the plurality of slot intervals, The method of claim 1 , wherein the specific slot is the first slot of one or more slots that belong to the specific slot interval.

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

4. The method of claim 1 , wherein the specific PMI corresponds to the specific slot interval.

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

6. The method of claim 1 , wherein a first slot of the one or more slots belonging to the specific slot interval corresponds to a CSI reference resource.

7. The method of claim 1 , wherein the time duration of the slot interval is the same as the period of the CSI-RS.

8. The method of claim 1 , wherein the plurality of slot intervals have the same time duration.

9. The method of claim 1 , wherein each of the plurality of PMIs indicates at least one predicted precoding matrix associated with a corresponding slot interval.

10. at least one transceiver; at least one processor coupled to the at least one transceiver; The at least one processor receiving at least one channel state information-reference signal (CSI-RS) from a network via the at least one transceiver; calculating a channel quality indicator (CQI) based on a specific precoding matrix indicator (PMI), the specific PMI being one of a plurality of PMIs corresponding to a plurality of slot intervals; transmit a channel state information (CSI) report to the network via the at least one transceiver, the CSI report including the one CQI and codebook information corresponding to the plurality of PMIs; The one CQI is associated with the specific PMI and a specific slot in a specific slot interval that is one of the plurality of slot intervals.

11. transmitting at least one channel state information-reference signal (CSI-RS) from a base station to a terminal; receiving, by the base station, a CSI report from the terminal, the CSI report including one channel quality indicator (CQI) and codebook information corresponding to 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 slot intervals; The method, wherein the one CQI is associated with the specific PMI and a specific slot of a specific slot interval, the specific slot interval being one of the plurality of slot intervals.

12. at least one transceiver; at least one processor coupled to the at least one transceiver; The at least one processor Transmitting at least one channel state information-reference signal (CSI-RS) to a terminal via the at least one transceiver; configured to receive, from the terminal via the at least one transceiver, a CSI report including one channel quality indicator (CQI) and codebook information corresponding to 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 slot intervals; The base station, wherein the one CQI is associated with the specific PMI and a specific slot in a specific slot interval that is one of the plurality of slot intervals.

13. at least one processor; and at least one computer memory operably coupled to said at least one processor and storing instructions for performing the method of any one of claims 1 to 9 when executed by said at least one processor.

14. at least one non-transitory computer-readable storage medium storing at least one instruction, A computer-readable storage medium, wherein the at least one instruction, when executed by at least one processor, controls an apparatus to perform the method of any one of claims 1 to 9.

Images