WO2019208992A1

WO2019208992A1 - Method for transmitting or receiving channel state information in wireless communication system and device therefor

Info

Publication number: WO2019208992A1
Application number: PCT/KR2019/004836
Authority: WO
Inventors: 정재훈; 강지원; 박해욱
Original assignee: 엘지전자 주식회사
Priority date: 2018-04-23
Filing date: 2019-04-22
Publication date: 2019-10-31

Abstract

Disclosed are a method for transmitting or receiving channel state information in a wireless communication system and a device therefor. Specifically, a method for reporting channel state information (CSI) by a terminal in a wireless communication system may comprise the steps of: receiving, from a base station, configuration information related to the CSI for a downlink channel; receiving, from the base station, at least one CSI-RS for reporting the CSI; deriving angle information from at least one of the configuration information and/or the CSI-RS; and deriving the CSI on the basis of the configuration information and the angle information, and reporting the CSI to the base station.

Description

)

【Specification】

[Name of invention]

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

Technical Field

The present invention relates to a wireless communication system, and more particularly, to a method for transmitting and receiving channel state information and a device for supporting the same.

Background Art

Mobile communication systems have been developed to provide voice services while ensuring user activity. However, the mobile communication system has expanded not only voice but also data service, and the explosive increase in traffic causes shortage of resources and users require faster services. Therefore, a more advanced mobile communication system is required. .

The requirements of the next generation of mobile communication systems will be able to accommodate the explosive data traffic, dramatically increase the data rate per user, greatly increase the number of connected devices, very low end-to-end latency, and high energy efficiency. It should be possible. For this purpose, dual connectivity, Massive Multiple Input Multiple Output (MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Ultra-Wideband ( Various technologies such as Super wideband support _/ Device Networking are being studied. [Detailed Description of the Invention]

[Technical problem]

The present specification proposes a method of reducing overhead of channel state information reporting (ie, feedback) in a wireless communication system. Specifically, the present disclosure relates to a method for reporting channel state information including information on linear combination (LC) codebooks that are efficient in terms of elaborate yet feedback overhead, based on the angular properties of the channels. Suggest.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

Technical Solution

A method for a terminal to perform channel state information reporting in a wireless communication system according to an embodiment of the present invention, wherein the method is related to the CSI for a downlink channel from a base station ^. Receiving configuration information; Receiving, from the base station, a CSI-RS for the CSI report; Calculating angular informat ion of the downlink channel based on at least one of the configuration information and / or the CSI-RS; And performing the CSI report to the base station by using the configuration information and the angle information. 2019/208992 1 »(includes 1/10 公 019/004836; The CSI report may include information on a linear combination (L codebook) based on the angle information.

In the method according to an embodiment of the present invention, the setting information may include transformation matrix information for calculating the angle information, estimation of a spatial rotation matrix, and a beam of the base station. information and / or load the entire page for the CSI reported size (total payload size) may include at least information of the ^Hi-me.

Further, in the method according to an embodiment of the present invention, the information on the beam of the base station, i) the oversampling factor and / or ii) the number of combined groups and the indicator of the corresponding beam ( index).

In addition, in an additive method according to an embodiment of the present invention, the angle information may include i) a signal direction, an angular spread, iii) a spatial rotation parameter, and / or iv The conversion matrix may include at least one of the number of beams and an index of a corresponding category.

The method may further include reporting the angle information to the base station, wherein the angle information may be periodic, aperiodic or semi-persistent. ) Can be set to be reported.

The method may further include receiving spatial rotation parameter setting information from the base station. The spatial rotation parameter setting information may be set by the base station based on the angle information.

In the method according to an embodiment of the present disclosure, the method may further include performing, by the base station, CSI reporting based on the spatial rotation parameter setting information.

In the method according to an embodiment of the present invention, the information about the LC codebook includes information related to a precoding matrix including a first matrix and a second matrix, wherein the first matrix is a wideband ( wideband) channel attribute, and the second matrix may correspond to a subband channel attribute.

In addition, in the method according to an embodiment of the present invention, the first matrix is set based on a spatial rotation matrix shared between the terminal and the base station, and the spatial rotation matrix is defined as the first matrix. It can be set based on the spatial rotation parameter.

Further, in the method according to an embodiment of the present invention, the method for the terminal to calculate the first spatial rotation parameter, comprising the steps of: setting a second spatial rotation parameter; Plotting a channel covariance matrix based on the second spatial rotation parameter; And calculating the first spatial rotation parameter based on the channel covariance matrix, wherein the first spatial rotation parameter is regarded as a valid value when the coefficient of the channel covariance matrix is greater than or equal to a specific threshold value and the number of valid coefficients. The first spatial rotation parameter can be calculated based on the value where is the smallest.

In addition, in the method according to an embodiment of the present invention, the first matrix is DFT beam index information is included as a component, and the DFT beam index may be set based on the order influencing the CSI reporting based on the angle information.

In the method according to an embodiment of the present invention, the second matrix includes a coupling coefficient ¾ · for the LC codebook, wherein the coupling coefficient is set based on the spatial rotation matrix. You can do

In a terminal in which a terminal performs channel state information reporting in a wireless communication system according to an exemplary embodiment of the present invention, the terminal is functional with an RF unit and a RF unit for transmitting and receiving a radio signal. A processor coupled to the processor, the processor configured to: receive configuration information related to the CSI for a downlink channel from a base station; Receive, from the base station, a CSI-RS for the CSI report; Calculating angular information of the downlink channel based on at least one of the configuration information and / or the CSI-RS; And controlling to perform the CSI report to the base station by using the configuration information and the angle information. The CSI report may include information on a linear combination (LC) codebook based on the angle information.

Further, in the terminal according to an embodiment of the present invention, the processor may control the angle information to be reported to the base station periodically, aperiodic, or semi-persistent. have. 2019/208992 1 »（： 1/10 公 019/004836

6 A base station in which a terminal performs channel state information reporting in a wireless communication system according to an embodiment of the present invention, wherein the base station includes a radio frequency (RF) unit and the RF unit for transmitting and receiving a radio signal. And a processor functionally connected with the processor, wherein the processor is configured to transmit configuration information related to the CSI for a downlink channel to a terminal; Send a CSI-RS for the CSI report to the terminal; And control to receive the CSI report from the terminal, wherein at least one of the configuration information and / or the CSI-RS is used by the terminal to calculate angular information of the downlink channel; The CSI report may include information on a linear combination (LC) codebook calculated based on the configuration information and the angle information.

Advantageous Effects

According to an embodiment of the present invention, the angular property of uplink and / or downlink is utilized, that is, based on a signaling path and angular spread information between a terminal and a base station. In addition, there is an effect of increasing the accuracy of the beam by selectively configuring the columns of a specific DFT.

In addition, according to an embodiment of the present invention, by performing a spatial rotation on the wireless channel, the sub-channel (sulf-channel) and the direction of the incoming signal with higher accuracy, the sub-channel field 2019/208992 1 »（： 1/10 公 019/004836

7 Can reduce power loss. In this case, there may be an effect of reducing the number of beams that are missed, and the combining coefficient (s) may also be briefly expressed, and the CSI of higher accuracy may be reported. The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

[Brief Description of Drawings]

, The accompanying drawings are included as part of the detailed description to aid the understanding of the present invention provides an embodiment of the present invention, will be ^described, the technical features of the present invention together with the description.

Figure 1 shows an example of the overall system structure of the NR to which the method proposed in this specification can be applied.

2 illustrates a relationship between an uplink frame and a downlink frame in a wireless communication system to which the method proposed in the present specification may be applied.

3 shows an example of a frame structure in an NR system.

FIG. 4 shows an example of a resource grid supported in a wireless communication system to which the method proposed in this specification can be applied. FIG. 5 shows antenna ports and neuralologies to which the method proposed in this specification can be applied. Examples of resource grids are shown.

6 shows an example of a self-contained structure to which the method proposed in this specification can be applied. 7 shows an example of a signal transmission and reception method.

8 shows an example of a signaling procedure between a terminal and a base station related to channel state information (CSI) reporting.

9 illustrates a two-dimensional active antenna system having 64 antenna elements in a wireless communication system to which the present invention can be applied. FIG. 1 ◦ illustrates a system in which a base station or a terminal has a plurality of transmit and / or receive antennas capable of forming 3D (3-Dimension) beams based on AAS in a wireless communication system to which the present invention can be applied.

11 illustrates a two-dimensional antenna system having cross polarization in a wireless communication system to which the present invention can be applied.

12 illustrates a transceiver unit model in a wireless communication system to which the present invention can be applied.

13 shows an example of a multi-panel antenna array to which the present invention can be applied.

14 is a diagram illustrating an example of a massive MIMO base station in a finite scattering environment.

15 shows an example of the azimuth angle of arrival (AoA) and the magnitude of energy for a UL channel.

FIG. 16 illustrates an example of channel sparsity effects to which spatial rotation and DFT operations are applied to which an embodiment proposed in the present specification may be applied.

17 shows an example of a signaling procedure between a base station and a terminal for CSI reporting to which an embodiment proposed in the present specification can be applied. 2019/208992 1 »(where 1 ^ 1 {2019/004836 FIG. 18) shows another example of a signaling procedure between a base station and a terminal for reporting 031 to which an embodiment proposed in the present specification can be applied.

19 shows an example of an operation flowchart of a terminal performing a 031 report in a wireless communication system to which the method proposed in this specification can be applied.

20 illustrates an example of an operation flowchart of a terminal performing a 0 £ 1 report in a wireless communication system to which the method proposed in this specification can be applied.

21 is a wireless communication system to which the method proposed in the present specification can be applied.

An example of the operation flowchart of the base station which receives a report is shown. FIG. 22 illustrates a block diagram of a wireless communication apparatus to which the methods proposed herein may be applied. 23 is another example of a block diagram of a wireless communication device to which the methods proposed herein may be applied.

24 is another example of a block diagram of a wireless communication device to which the methods proposed herein may be applied.

FIG. 25 is another example of a block diagram of a wireless communication device to which the methods proposed herein may be applied.

[Form for implementation of invention]

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description of the invention Include specific details to provide a thorough understanding. However, one of ordinary skill in the art appreciates that the present invention could be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal and a receiver may be part of a base station. The base station may be represented by the first communication device and the terminal by the second communication device. A base station (BS) is a fixed station, a Node B, an evolved-NodeB (eNB), a Next Generation NodeB (gNB), a base transceiver system (BTS), an access point (AP), a network (5G). Network), AI system, RSU (road side unit), vehicle, robot _/ (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) ¾ 丄 1 ，

It can be replaced by terms such as VR (Virtual Reality) device. In addition, a terminal may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber staton (SS), and an AMS ( Advanced Mobile Station (WT), Wireless Terminal (WT), Machine-Type

Communication

, M2M (Machine-to-Machine)

, D2D (Device— to-Device) devices, vehicles, robots, AI modules, drones (Unmanned 2019/208992 1 »(： 1/10 公 019/004836

11

Aerial Vehicle (UAV), Augmented Reality (AR) device, VR (Virtual)

Can be replaced by the term device capability. The following techniques can be used for various radio access systems such as CDMA, FDMA, TDMA, OFD1MA, SC-FDMA, and the like. CDMA can be implemented with wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2. TDMA supports GSM (Global System for Mobile communications) / GPRS (General

Packet Radio Serv 丄 ce) / EDGE (Enhanced Data Rates for GSM

Wireless technology such as Evolution). OFDMA is IEEE 802.11

(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (Evolved UTRA)

. .

It may be implemented in a wireless technology such as. UTRA is UMTS (Universal Mobile)

It is part of Telecommunications System). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA and LTE-A (Advanced) / LTE-A pro is an evolution of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolution of 3GPP LTE / LTE-A / LTE-A pro. For clarity, the description will be based on 3GPP communication systems (eg, LTE-A, NR), but the technical spirit of the present invention is not limited thereto. LTE refers to technology after 3GPP TS 36. xxx Release 8. In detail, LTE technology after 3GPP TS 36. xxx Release 10 is referred to as LTE-A, and LTE technology of 3GPP TS 36. xxx Release 13 ⁰ 1 · ^ is LTE-A pro.

3GPP

■ means technology after TS 38. xxx Release 15. LTE / NR may be referred to as a 3GPP system. “Xxx” means standard document detail number. 2019/208992 1 »(： 1/10 公 019/004836

12

LTE / NR may be collectively referred to as 3GPP system. Background, terminology, abbreviations and the like used in the description of the present invention may refer to the matters described in the standard documents published prior to the present invention. For example, see the following document:

3GPP LTE

36.211: Physical channels and modulation

36.212: Multiplexing and channel coding

36.213: Physical layer procedures

36.300: Overall description

36.331: Radio Resource Control (RRC)

3GPP NR

38.211: Physical channels and modulation

38.212: Multiplexing and channel coding

38.213: Physical layer procedures for control

38.214: Physical layer procedures for data

38.300: NR and NG-RAN Overall Description

36.331: Radio Resource Control (RRC) protocol specification

As more communication devices demand larger communication capacities, there is a need for improved mobile broadband communication compared to conventional radio access technology. In addition, massive MTC (Machine Type Communications) provides various services anytime, anywhere by connecting multiple devices and objects. 2019/208992 1 »（： 1/10 公 019/004836

13 is also one of the major issues to be considered in next-generation communications. In addition, communication system design considering services / terminals that are sensitive to reliability and latency is being discussed. Like this, eMBB (enhanced mobile broadband coinrnuncation), Mmtc (massive MTC), URLLC (Ultra-Reliable and Low Latency Communication), etc.

Introduction of radio access technology is discussed, and for convenience, the technology is referred to as NR. Is a representation of an example of 5G radio access technology (RAT).

The new RAT system including the NR uses an OFDM transmission scheme or a similar transmission scheme. The new RAT system may follow OFDM parameters different from the OTOM parameters of LTE, or the new RAT system follows the existing LTE / LTE- A's numerology, but with a larger system bandwidth (e.g., 100 MHz). I can have it. Alternatively, one cell may support a plurality of neurology. That is, terminals operating with different neurology may coexist in one cell.

Numerology corresponds to one subcarrier spacing in the frequency domain. By scaling the reference subcarrier spacing to an integer N, different numerology can be defined. Term Definition

: 61 / [

6's evolution (6 '/ 0111: 1011), which supports connections to £ 0 and 的 (:. gNB: Node that supports NR as well as connection with NGC.

New RAN: A radio access network that supports NR or E-UTRA or interacts with NGC.

Network slice: A network slice defined by the operator to provide an optimized solution for specific market scenarios that require specific requirements with end-to-end coverage.

Network function: The network function is a logical NG-C within a network infrastructure with a well-defined external interface and well-defined functional behavior. The control used for the NG2 reference point between the new RAN and the NGC. Flat interface.

NG-U: User plane interface used for the NG3 reference point between the new RAN and NGC.

Non-standalone NR: A deployment configuration where a gNB requires an LTE eNB as an anchor for control plane connection to EPC or an eLTE eNB as an anchor for control plane connection to NGC.

Non-Standalone E-UTRA: Deployment configuration requiring gNB as anchor for control plane connection with eLTE eNB7> NGC.

User plane gateway: The endpoint of the NG-U interface. System general

1 is an overall view of a ship to which the method proposed in this specification may be applied. An example of the system structure is shown. Referring to FIG. 1, NG-RAN is defined as gNBs that provide control plane yoy protocol termination for NG-RA user plane (new. AS sublayer / PDCP / RLC / MAC / PHY) and UE (User Equation). It is composed. The gNBs are interconnected via an X _n interface. The gNB is also connected to the NGC via the NG interface. More specifically, the gNB can access and control AMF (NMF) through an N2 interface.

Mobility Management Function), which is connected to UPF (User Plane Function) through N3 interface.

NR (New Rat) Numerology & Frame Structure

Multiple numerologies can be supported in an NR system. Here _/, enumeration roll which may be defined by a sub-carrier spacing (subcarrier spacing) and CP (Cyclic Prefix) overhead. At this time, a plurality of subcarrier spacings can be derived by scaling the basic subcarrier spacing to an integer N (or H). Also, even if it is assumed that very low subcarrier spacing is not used at very high carrier frequencies, the numerology used may be selected independently of the main fruit band. In addition, in the NR system, various prearm structures according to a number of numerologies may be supported. Hereinafter, orthogonal frequency (OFDM) that may be considered in an NR system

:

Division Multiplexing (Normal) and frame structure. 2019/208992 1 »（： 1/10 公 019/004836

In the 16-Yo system, a number of 0 0 numerologies can be defined as shown in Table 1.

Table 1

Frame structure in NR systems

In this regard, the size of the various fields in the time domain

Expressed in multiples of time. From here,

And vV _f = 4096. Downlink (downlink) and uplink (uplink) transmission consists of a radio frame having a period of i / and ... ⁼ 10ms. Here, the radio frame is composed of lo subframes each having a interval of ¾ = te _a A / 100 ^ T: = lms. In this case, there may be a set of frames for uplink and a set of frames for downlink.

As shown in FIG. 2, transmission of an uplink frame number from a user equipment (UE) should start before T _TA = N _TA T _S than the start of the corresponding downlink frame in the corresponding UE.

For numerology ju, slots are in a subframe

-numbered in increasing order of l} and numbered in increasing order of <4), ..., 尺 = within a radio frame. One slot is located; ^ 2019/208992 1 »（： 1/10 公 019/004836

Consist of 17 consecutive OFDM symbols, A _mb is determined according to the used numerology and slot configuration. Slot in subframe

Start of OFDM symbol in the same subframe

Sorted by start and time. Not all terminals can transmit and receive at the same time, which means that not all OFDM symbols of a downlink slot or an uplink slot can be used. Table 2 shows slots in normal (normal ñ CP _: OFDM symbol;

Radio frame »rsubframe // Shows the number of slots per frame ( ^slQt ) and the number of slots per subframe ( ^slQt ). Table 3 shows the number of OFDM symbols per slot in extended ñ CP and the number of slots per radio frame. , The number of slots per subframe.

[Table 2]

Table 3

3 shows an example of a frame structure in an NR system. 3 is merely for convenience of description and does not limit the scope of the invention. For Table 3, if = 2, i.e. subcarrier spacing,

As an example of the case where SCS) is 60 kHz, referring to Table 2, one subframe (or frame) may include four slots, and 1 shown in FIG. Subframes = {1, 2, 4} Slots are one example, and the number of slot (s) that can be included in one subframe may be defined as shown in Table 2.

In addition, the mini-slot may consist of two, four or seven symbols, and may consist of more or fewer symbols.

With regard to physical resources in the NR system, antenna ports, resource grids, resource elements, resource blocks, carrier parts, etc. May be considered.

Hereinafter, the physical resources that may be considered in the NR system will be described in detail.

First, with respect to the antenna port, the antenna port is defined so that the channel on which the symbol on the antenna port is carried can be inferred from the channel on which another symbol on the same antenna port is carried. If the large-scale property of a channel carrying a symbol on one antenna port can be deduced from the channel carrying the symbol on another antenna port, then the two antenna ports are quasi co-located or QC / QCL. quasi co-location relationship. Here, the broad characteristics include delay spread, Doppler spread, frequency shift _f average received power, change

¾ (Received Timing)

It includes the above.

FIG. 4 shows an example of a resource grid supported by a wireless communication system to which the method proposed in this specification can be applied. 2019/208992 1 »（： 1/10 公 019/004836

19 Referring to FIG. 4, the resource grid is in the frequency domain

By way of example, one subframe includes 14 _2 OFDM symbols, but is not limited thereto.

In NR systems, the transmitted signal is

One or more resource grids composed of subcarriers, and

Described by OFDM symbols. From here,

Mr. £. Above

Represents the maximum transmission bandwidth, which may vary between uplink and downlink as well as the numerologies.

In this case, as shown in FIG. 5, one resource grid may be set for each pneumatics // and antenna port p.

FIG. 5 shows examples of an antenna port and a number of resource grids based on each numerology to which the method proposed in this specification can be applied.

Each element of the resource grid for the _{numeric jU} and the antenna port is referred to as a resource element and is an index pair

Uniquely identified by From here,

Is the index on the frequency domain,

/ = 0, ... rA 歌 ^ -1 refers to the position of the symbol in the subframe. When referring to a resource element in a slot, an index pair (hour) is used. Where / = 0, ... ^; _mb -l.

The resource factor for the numerology f and antenna port corresponds to the complex value a −. If there is no risk of confusion, or if a particular antenna port or numerology is not specified, the indices P and // can be dropped so that the complex value is a _k ^{ f or a _{k ]} o be) 2019/208992 1 »（： 1/10 公 019/004836

There are 20.

Also, physical

Resource 1310｝ 0 is in the frequency domain

# _s f = 12 consecutive subcarriers

Point A serves as a common reference point of the resource block grid and can be obtained as follows.

OffsetToPointA for the PCell downlink represents the frequency offset between the lowest subcarrier of the lowest resource block and point A overlapping with the SS / PBCH block used by for the initial cell selection, 15 kHz subcarrier spacing for FR1 and FR2 Expressed in resource block units assuming a 60kHz subcarrier spacing for;

absoluteFrequencyPointAO represents the frequency-location of point A expressed as in absolute radio-frequency channel number (ARFCN)

Common resource blocks are numbered upwards from ◦ in the frequency domain for subcarrier spacing ¹ .

The center of the subcarrier ◦ of the common resource block ◦ for the subcarrier spacing coincides with 'point A'. The resource element (k, l) for setting the common resource block number R _B and the subcarrier spacing in the frequency domain may be given by Equation 1 below.

[Equation 1]

Where 소 ⁼ 0 for the subcarrier centered on point A 2019/208992 1 »（： 1/10 公 019/004836

21 can be defined relative to 0: 111 七. Physical resource blocks are zero-based within the bandwidth part (BWP).

Numbered up to ⁷ , the number of BWPs. The relationship between the physical resource block bird and the common resource block ^ CRB in BWP i may be given by Equation 2 below.

[Equation 2]

, x _/ sunt

CRB ⁼ PRB ⁺ BWP, where may be a common resource block in which the BWP starts relative to common resource block 0. Self-contained structure

The TDD (Time Division Duplexing) structure considered in the NR system is a structure that processes both uplink (UL) and downlink (DL) in one slot (or subframe). This is to minimize the latency of data transmission in the TDD system, and the structure may be designated as a self-contained structure or a self-contained slot.

6 shows an example of a self-contained structure to which the method proposed in this specification can be applied. 6 is merely for convenience of description and does not limit the scope of the present invention.

Referring to Figure 6, like in the case of legacy LTE ^0], one of the transmission units: a case (for example, slots, a sub-frame) is composed of 14 OFDM (Orthogonal Frequency Division Multiplexing) symbol (symbol) is assumed. 2019/208992 1 »（： 1/10 公 019/004836

22, region 602 means a downlink control region, and region 604 means an uplink control region. In addition, regions other than regions 602 and 604 (groups, regions without separate indication) may be used for transmission of downlink data or uplink data.

That is, uplink control information and downlink control information may be transmitted in one self-contained slot. On the other hand, in the case of data, uplink data or downlink data may be transmitted in one self-contained slot.

In the structure shown in FIG. 6, downlink transmission and uplink transmission are sequentially performed in one self-contained slot, and transmission of downlink data and reception of uplink ACK / NACK may be performed.

As a result, when an error in data transmission occurs, the time required for retransmission of data can be reduced. In this way, delays associated with data delivery can be minimized.

In the self-contained slot structure as shown in FIG. 6, a process of the base station (eNodeB, eNB, gNB) and / or terminal (UE, User Equipment) switching from a transmission mode to a reception mode Alternatively, a time gap for switching from a reception mode to a transmission mode is required. In relation to the time gap, when uplink transmission is performed after downlink transmission in the self-contained slot, some OFDM symbol (s) may be set to a guard period (GP). 2019/208992 1 »（： 1/10 公 019/004836

23

Wireless Signal Transceiver Method FIG. 7 is a diagram illustrating an example of a signal transmission and reception method. Referring to FIG. 7, when the UE is powered on or enters a new cell, the UE performs an initial cell search operation such as synchronizing with the base station (S701). To this end, the UE receives a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station, synchronizes with the base station, and acquires information such as a cell ID. Can be. Thereafter, the terminal may receive a physical broadcast channel from the base station to obtain broadcast information in a cell. Meanwhile, the UE may check a downlink channel state by receiving a downlink reference signal (DL) in an initial cell search step.

:

Downlink Control Channel; More specific system information can be obtained by receiving a Physical Downlink Control Channel (PDSCH) according to the PDCCH) and the information carried on the PDCCH (S702). On the other hand, when the first access to the base station or there is no radio resource for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (steps S703 to S706). To this end, the terminal is identified through a Physical Random Access Channel (PRACH ñ).

:

Transmit the sequence as a preamble (S703 and S705), and PDCCH and the corresponding PDSCH 2019/208992 1 »（： 1/10 公 019/004836

A response message for the preamble can be received through 24 (S704 and S706). In the case of a contention-based RACH, a Stock Resolution Procedure may be performed.

After performing the above-described procedure, the UE performs a PDCCH / PDSCH reception (S707) and a physical uplink shared channel (PUSCH) / physical uplink control as a general uplink / downlink signal transmission procedure.

Physical Uplink Control Channel (PUCCH) transmission (S708) may be performed. In particular, the UE controls downlink control information through the PDCCH.

Control Information; DCI). Here, the DCI includes control information such as resource allocation information for the terminal, and the format is different according to the purpose of use.

Meanwhile, the control information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). ), And the like. In the 3GPP LTE system _/ UE can transmit the above-described control information, such as CQI / PMI / RI through the PUSCH and / or PUCCH.

Table 4 shows an example of the DCI format in the NR system.

Table 4

Referring to Table 4, DCI format 0JD is used for scheduling of PUSCH in one cell.

Information included in DCI format 0_0 is transmitted by being CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI. In addition, DCI format 0_1 is used to reserve a PUSCH in one cell. Information contained in DCI format 0_1 may be obtained by C-RNTI or: CS-RNTI or SP-CSI-RNTI or MCS-C-RNTI.

CRC scrambled and sent. DCI format 1_0 is used for scheduling of PDSCH in one DL cell. Information included in DCI format 1_0 is transmitted by being CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI. DCI format 1_1 is in one cell _. Used for scheduling of PDSCH. Information included in DCI format 1_1 is transmitted by being CRC scrambled by C-RNTI or CS-RNTI or MCS-C-RNTI. DCI format 2 1 is used to inform the PRB (s) and OFDM symbol (s) that the terminal may assume no transmission.

The following information included in DCI format 2_1 is CRC scrambled by INT-RNTI and transmitted.

CSI related behavior

In NR (New Radio) systems, channel state information-reference signal (CSI-RS) can be used for time and / or frequency tracking, CSI computation, LI (layer 1) -RSRP (reference). 2019/208992 1 1/10 公 019/004836

26 signal received power It is used for computation and mobility. Here, CSI computation is related to CSI acquisition and L1-RSRP computation is related to beam management (BM).

Channel state information (CSI) refers to information that may indicate the quality of a wireless channel (or also referred to as a link) formed between a terminal and an antenna port.

8 is a flowchart illustrating a complete process of a CSI related procedure.

To do any of the uses of the CSI-RS as described above, the terminal (such as: user equipment, UE) is the set (configuration) information related to the ^{CSI (radio resource control) RRC 7} 1 flag state through the signal丄ng (e.g. : general Node B (gNB)) (S810).

The CSI-related configuration information may include information related to CSI-IM (interference management) resources, information related to CSI measurement configuration, information related to CSI resource configuration, and information related to CSI-RS resource. Or CSI report configuration related information.

Iii) CSI-IM resource related information includes CSI-IM resource information, CSI-IM support set ¾ iL (resource set information)

It may include. CSI-IM resource set is CSI-IM resource set

Identified by an identifier (ID), one resource set includes at least one CSI-IM resource. Each CSI-IM resource is a CSI-IM 2019/208992 1 HE1 / 10 公 019/004836

27 identified by resource 113.

ii) CSI resource configuration related information is CSI-

5.¾¾ with ResourceConfig IE

¹ The CSI resource configuration related information defines a group including at least one of a NZP (non zero power) CSI-RS resource set _r CSI IM resource set or CSI-SSB resource set. That is, the CSI resource configuration related information includes a CSI-RS resource set list, and the CSI-RS resource set list includes at least one of an NZP CSI-RS resource set list, a CSI-IM resource set list, or a CSI-SSB resource set list. It may include one. The CSI-RS resource set is identified by a CSI-RS resource set ID, and one resource set shoots at least one CSI-RS resource-each CSI-RS resource is identified by a CSI-RS resource ID

S _/ NZP CSI-RS resource for each parameter set represents the use of a CSI-RS as shown in Table 5 (Examples: BM-related 'repetition' parameter, tracking relevant 'trs-Info' parameter) may be set °].

Table 5 shows an example of the NZP CSI-RS resource set IE.

Table 5

And, repetition corresponding to higher layer parameter 2019/208992 1 »(： 1/10 公 019/004836

28

SI 亡 is CSI-RS-ResourceRep of 1 ^ 1 parameter

Corresponds.

Iii) CSI report configuration related information includes a report configuration type parameter indicating a time domain behavior and a reportQuantity parameter indicating a CSI related quantity to be reported. ^ 7] English ^-^ (time doma 丄 IV behav 丄 or) # Can be periodic, aperiodic or semi-persistent.

CSI report configuration related information may be expressed as CSI-ReportConfig IE, and Table 6 below shows an example of CSI-ReportConfig IE.

Table 6

2019/208992 1 »(： 1/10 公 019/004836

29

The terminal measures the CSI based on the configuration information related to the CSI (S820). In addition, the measurement of the CSI may be expressed by the calculation of the CSI, the calculation of the CSI.

The CSI measurement may include (1) a CSI-RS reception process (S821) of the UE, and (2) a process (S826) of calculating the CSI through the received CSI-RS, which will be described in detail. Will be described later.

The CSI-RS is configured to map resource elements (REs) of CSI-RS resources in a time and frequency domain by higher layer parameter CSI-RS-ResourceMapping.

Table 7 shows an example of the CSI-RS-ResourceMapping IE.

[Table 7]

In Table 7, the density (density, D) represents the density of the CSI-RS resource that jeukjeong in RE / port / PRB (physical resource block) /

Shows the number of antenna ports. 2019/208992 1 »（： 1/10 公 019/004836

30

The terminal reports the measured CSI to a base station (S830). In addition, the CSI report may be represented by CSI feedback.

Here, when the quantity of CSI-ReportConfig in Table 6 is set to 'none (or No report)', the terminal may omit the report.

However, even when the quantity is set to 'none (or No report)', the terminal may report to the base station.

When the quantity is set to 'none', it is the case that triggers aperiodic TRS or r petit 丄 on is set.

Here, the report of the terminal can be omitted only when the repetition is set to 'ON'. Massive MIMO

A MIMO system with multiple antennas can be referred to as a Massive MIMO system, and is attracting attention as a means to improve spectral efficiency, energy efficiency, and processing complexity. .

Recently, 3GPP has started to discuss the Massive MIMO system to meet the requirements of the spectrum efficiency of future mobile communication systems. Massey 旦 MIMO ^-

Full-Dimension MIMO (FD-MIMO) SS is referred to.

In the wireless communication system after the LTE release (Rel: release) -12, the introduction of an active antenna system (AAS) is considered. Unlike conventional passive antenna systems, where amplifiers and antennas that can adjust the phase and magnitude of the signal are separated, AAS refers to a system in which each antenna includes an active element such as an amplifier.

The table eliminates the need for separate cables, connectors, and other hardware to connect the amplifier to the antenna depending on the use of the active antenna, and thus has high efficiency in terms of energy and operating costs. In particular, AAS supports an electronic beam control scheme for each antenna, thereby enabling advanced MIMO technologies such as forming a precise beam pattern or a three-dimensional beam pattern in consideration of beam direction and width.

With the introduction of advanced antenna systems such as AAS, large-scale MIMO structures with multiple input / output antennas and multi-dimensional antenna structures are also considered. For example, unlike a conventional straight antenna array, when a 2-dimensional (2D) antenna array is formed, a three-dimensional beam pattern can be formed by the active antenna of the yaw.

FIG. 9 illustrates a two-dimensional active antenna system having 64 antenna elements in a wireless communication system to which the present invention can be applied. In FIG. 9, a typical two-dimensional (2D) antenna array is illustrated. As shown in FIG. 9, a case in which N_t = N_v · N_h antennas has a square shape may be considered. Where h is the number of antenna columns in the horizontal direction

Indicates the number of antenna rows in the direction.

With this 2D antenna arrangement, the radio wave can be controlled both in the vertical direction (elevation) and in the horizontal direction (azimuth) to control the transmission beam in three-dimensional space. have. This type of wavelength The control mechanism may be referred to as three-dimensional beamforming. 10 illustrates a system in which a base station or a terminal has a plurality of transmit / receive antennas capable of forming 3D (3-Dimension) beams based on AAS in a wireless communication system to which the present invention can be applied.

FIG. 10 is a diagram illustrating the above-described example, and includes a two-dimensional antenna array (that is,

It illustrates a 2D-AAS) ⁰ 1 yonghan 3D ^ MIMO system.

:

When using the 3D beam pattern from the perspective of the transmitting antenna, it is possible to perform quasi-static or dynamic beam forming in the vertical direction as well as the horizontal direction of the beam, and may be considered an application such as vertical sector formation. .

In addition, from the viewpoint of the receiving antenna, when the receiving beam is formed using a large receiving antenna, a signal power increase effect according to the antenna array gain can be expected. Therefore, in the uplink, the base station can receive a signal transmitted from the terminal through a plurality of antennas, the terminal can set its transmission power very low in consideration of the gain of the large receiving antenna to reduce the interference effect. There is an advantage.

Of 2D Planar Antenna Array Model Considering Polarization _. In this case, it can be illustrated as shown in FIG.

Unlike conventional MIMO systems based on passive antennas, systems based on active antennas are characterized by weighting the active elements (e.g., amplifiers) attached (or included) to each antenna element. 0 2019/208992 1 1/10 公 019/004836

33 You can adjust the gain dynamically. Since the radiation pattern depends on the antenna arrangement, such as the number of antenna elements, antenna spacing, etc., the antenna system can be modeled at the antenna element level.

An antenna array model as shown in the example of FIG. 11 may be represented as (M, N, Mi, which corresponds to a parameter characterizing the antenna array structure.

M is the number of antenna elements (ie in each column) that have the same polarization in each column (ie in the vertical direction).

The number of antenna elements with + 45 ^° slant or the number of antenna elements with-45 ^° slant in each column.

N represents the number of columns in the horizontal direction (ie, the number of antenna elements in the horizontal direction).

The driving represents the number of dimensions of polarization. As in the case of FIG. 11, P = 2 for cross polarization, but P = 1 for co-polarization.

The antenna port may be mapped to a physical antenna element. The antenna port ñ may be defined by a reference signal associated with the antenna port. For example, in an LTE system, the antenna port ◦ is associated with a cell-specific reference signal (CRS), and the antenna port 6 is a PRS ( Positioning Reference Signal) In one example, there may be a one-to-one mapping between an antenna port and a physical antenna element, where a single cross polarization antenna element is a downlink MIM0 or This may be the case when used for downlink transmission diversity. For example, antenna port 0 may be mapped to one physical antenna element, while antenna port 1 may be mapped to another physical antenna element. In this case, two downlink transmissions exist from the terminal point of view. One is associated with a reference signal for antenna port 0 and the other is associated with a reference signal for antenna port 1.

In another example, a single antenna port can be mapped to multiple physical antenna elements. This may be the case when used for beamforming. Beamforming can direct downlink transmissions to specific terminals by using multiple physical antenna elements. In general, this can be achieved by using an antenna array consisting of multiple columns of multiple cross polarization antenna elements. In this case, at the terminal, there is a single downlink transmission generated from a single antenna port. One relates to the CRS for antenna port 0 and the other relates to the CRS for antenna port 1.

That is, the antenna port represents the downlink transmission and the downlink transmission at the terminal, not the actual downlink transmission transmitted from the physical antenna element at the base station.

In another example, multiple antenna ports are used for downlink transmission, but each antenna port may be mapped to multiple physical antenna elements. In this case, the antenna array may be used for downlink MIMO or downlink diversity. For example, antenna ports 0 and 1 may each map to multiple physical antenna elements. In this case, two downlinks from the terminal point of view There is a transmission. One is associated with a reference signal for antenna port 0 and the other is associated with a reference signal for antenna port 1.

In FD-MIMO, MIMO precoding of data streams may go through antenna port virtualization, transceiver unit (or transceiver unit) (TXRU) virtualization, and antenna element pattern.

Antenna port virtualization allows the stream on the antenna port to be precoded on the TXRU. TXRU virtualization allows the TXRU signal to be precoded on the antenna element. The antenna element pattern may have a directional gain pattern of the signal radiated from the antenna element.

In conventional transceiver modeling, with an antenna port. Static one-to-one mapping between TXRUs is assumed, and the TXRU virtualization effect is combined into a static (TXRU) antenna pattern that includes both the effects of the TXRU virtualization and antenna element pattern. Antenna port virtualization can be performed in a frequency-selective manner. In LTE, an antenna port is defined with a reference signal (or pilot). For example, for precoded data transmission on an antenna port, DMRS is transmitted in the same bandwidth as the data signal, and DMRS ^-data are all precoded with the same precoder (or the same TXRU virtualized precoding). For CSI measurement, the CSI-RS is transmitted through multiple antenna ports. In the CSI-RS transmission, the precoder characterizing the mapping between the CSI-RS port and the TXRU may be designed with a unique matrix so that the UE may estimate the TXRU virtualization precoding matrix for the data precoding vector.

TXRU

TXRU v 丄！: tualizat 丄 on)

Two-dimensional TXRU virtualization is discussed, with respect to A description with reference to the drawings below.

In ID TXRU virtualization, M_TXRU TXRUs consist of a single column antenna array with the same polarization.

It is associated with M antenna elements.

In 2D TXRU virtualization, the TXRU model configuration corresponding to the antenna array model configuration (M, N, P) of FIG. 11 may be represented as (M_TXRU, N, M. Here, M_TXRU is a 2D-like column, the same polarization (polar TXzation) means the number of TXRUs, and always satisfies M_TXRU <M. That is, the total number of TXRUs is

Same as M_TXRUXNXP.

The TXRU virtualization model is based on the correlation between the antenna element and the TXRU, as shown in FIG. 12 (a). TXRU virtualization model option-1: sub-array partition model and FIG. Model Option-2: Can be distinguished by a full-connection model.

Referring to FIG. 12 (a), in the case of a sub-array partition model, antenna elements are divided into multiple antenna element groups, and each

TXRU is associated with one of the groups.

Referring to FIG. 12 (b), in the full-connection model, signals of multiple TXRUs are combined and delivered to a single antenna element (or an array of antenna elements).

M same polarizations (co-) in one column in FIG. 0 2019/208992 1 »（： 1/10 公 019/004836

37 is a transmission signal vector of the antenna elements. w is: the wideband TXRU virtualization weight vector, and? is the wideband TXRU virtualization weight matrix. x is the signal vector of M_TXRU TXRUs.

Here, the mapping between the antenna port and the TXRUs may be one-to-one or one-to-many.

The TXRU-to-element mapping in FIG. 12 shows only one example, and the present invention is not limited thereto, and TXRU and antenna elements may be implemented in various forms from a hardware point of view. The present invention can be equally applied to the mapping between them.

Panel antenna array

FIG. 13 shows a generalized multi panel antenna array, consisting of Mg and Ng panels in the horizontal and vertical domains, respectively, with one single panel each being M. FIG. It consists of N columns and N rows. In FIG. 13, a 2-pole antenna is assumed. Accordingly, the total number of antenna elements is 2 * M * N * Mg * Ng.

As shown in FIG. 13, a multi-panel antenna array is supported in a new radio access technology (RAT) environment. In the present invention, first, a single panel antenna array will be described in consideration of the present invention, but this is only for convenience of description and of the present invention. 2019/208992 1 »(： 1/10 公 019/004836

It does not limit the scope.

In this case, the two-dimensional beam 20 which can be applied to a two-dimensional antenna array in a single panel 20

삐) can be defined as in Equation 3. In Equation 3,

Represents the index of the one-dimensional DFT (1D-DFT) codebook of the 2 ^ domain.

[Equation 3]

In Equation 3, N1 and denote the number of antenna ports per pol of I ^st and 2 ^nd dimensions in a single panel. ol and o2 represent the oversampling factor ñ in the I ^st and 2 ^nd dimensions (dimens 丄 on) in the panel.

As mentioned above, due to the massive antenna configuration (eg N _T > 1) at the transmission end, the resolution of the Discrete Fourier Transform (DFT) for each domain in the panel can be improved; . In addition, it may be possible to estimate the angle and angular spread of the signal with relatively high accuracy through DFT operation.

For example, horizontal and / or vertical ULAs 2019/208992 1 »(： 1/10 2019/004836

39

In a (Uniform Linear Array) environment, channel information may be converted into sub-channels configured at uniform intervals in the entire horizontal and / or vertical beam-space through a DFT operation. In this case, points (or points) having a value other than ◦ may be interpreted as an angular spread around a specific direction of arrival (DOA) of a channel. In addition, in the finite scattering wireless environment generated in a system considering a massive MIMO system in a high frequency band as shown in FIG. 14, the number of sub-channels having a significant value is limited and dense sparse shape. see.

On the other hand, from the practical implementation point of view, the number of antennas at the transmitting end is finite and this limits the resolution of the DFT. In this case, the power for each sub-channel is lost to the adjacent sub-channels, so that the number of non-zero sub-channel powers increases as compared with when the resolution of the DFT is high. have. This relatively weakens the sparsity of the channel, which may be a burden on the feedback overhead for the channel. In order to solve this problem, by performing spatial rotation of the radio channel, the direction of the incoming signal with the sub-channels with higher accuracy to reduce the power loss of the sub-channels The method can be considered. Through the above method, the number of combined beams may be reduced. In addition, the coupling coefficient (s) (combining coefficient (s)) ° 1 can be represented simply, the terminal may report a higher accuracy of the channel state information.

111 广 1) 1 angle in frequency division duplexing (FDD) 2019/208992 1 »(： 1/10 公 019/004836

40 reciprocity

Unlike TDD (Time Division Duplexing), in case of FDD using different carrier frequencies for a line signal, reciprocity for channel information cannot be guaranteed. However, due to the characteristics of the ultra-high frequency band, reciprocity in the angular domain with respect to the transmission and reception signals may exist.

Here, angular reciprocity may mean that the path or angle of the uplink (UL) signal and the angular spread are the same in the downlink (DL). This may be achieved even in an FDD environment in which a difference in carrier frequencies between UL and DL is about several GHz.

Therefore, the angular property of can be calculated through the angular information # obtained through the UL signal, and by using this, the number of instantaneous channel gains to be fed back by the terminal can be greatly reduced. have. In one example, the characteristics of the UL channel may be the same as FIG. 15.

Referring to FIG. 15, it can be confirmed that valid information of a channel is concentrated in a limited support region for a specific number of AoAs. Based on this characteristic, an azimuth angle of departure (AoD) of a base station is provided. And a range of the corresponding support area may be estimated based on | f_UL-f_DL |, which is a difference value of carrier frequency, and may be referred to as UL-DL angle reciprocity. Therefore, the effective complex value of the DL channel covariance matrix In terms of location and area, the range of AoD and the corresponding support area through the power-angle spectrum may have a high correlation with each other. Improved channel sparsity through spatial rotation

In the case of the method proposed in the present specification, the terminal and / or the base station obtains the channel information in downlink (DL) by using a low-rank characteristic of channel information based on sparsity of a massive MIMO radio channel environment. It may be possible to significantly reduce the head.

In order to perform this, it may be required to estimate and utilize angular information of a channel corresponding to a low-rank. Conventional methods such as MUSIC (mult 丄 pie signal classification) and ESPRIT (estimation of signal parameters via rotational invariance technique) not only cause high complexity in a massive antenna environment, but also do not reflect the characteristics of incoming signals.

Therefore, through signal processing and DFT operation based on an antenna array, angle information in a massive MIMO environment may be efficiently obtained and used for channel estimation. Where the DFT matrix

The (p, q) th element may be configured as follows.

[Equation 4]

In Equation (4), it is ^transmitted, ranging value: represents a number of antenna ports (e.g., base _station) is, That is, the resolution of the DFT can be greatly improved due to the massive antenna configuration of the transmitter (eg, N _T »1), and the angle and angular spread of the signal can be determined with relatively high accuracy through the DFT operation. It may be possible to.

For example, in a ULA environment, the DFT operation converts channel information into sub-channels that are organized at uniform intervals in the entire beam-space. In this case, points (or points) having a non-zero value may be interpreted as angular spread around a specific DoA (direction of arrival) of the channel. In the wireless environment contemplated herein, it is assumed that the number of such sub-channels is limited and densely sparse.

On the other hand, from the practical implementation point of view, the number of antennas of the transmitting end is finite and this may limit the resolution of the DFT. In this case, the power of each sub-channel leads to an outflow to adjacent sub-channels, so that the number of sub-channels whose power is not ◦ may increase compared to when the resolution of the DFT is high. . This may weaken the sparsity of the channel and may cause a burden on the feedback to the channel.

In view of this, a method of reducing the power leakage of the subchannels by performing spatial rotation of the radio channel with a higher accuracy of alignment of the subchannels and the incoming signal is considered. Can be. For example, the sparsity effect of the channel through spatial rotation and DFT operation may be as shown in FIG. 16.

16 is a spatial rotation and can be applied to the embodiments proposed herein 2019/208992 1 »（： 1/10 公 019/004836

43

An example of channel sparsity effects to which a DFT operation is applied is shown. 16 is merely for convenience of description and does not limit the scope of the present invention.

Referring to FIG. 16, in the conventional DFT operation, channel information is represented by 28 subchannels, whereas subchannels may be represented by 11 when spatial rotation is performed principally. In the wireless communication environment described above, linear combination (LC) codebook (LC codebook), covariance matrix feedback for accurate channel state information (CSI) reporting while efficiently reducing feedback overhead. High resolution reporting (i.e., feedback) methods are considered.

Hereinafter, the contents discussed about the reporting methods will be described in detail.

i) Type II CSI Category I

Dual-stage codebook W consists of W = W1W2. W1 consists of a set of L orthogonal beams of the 2D DFT beams. The set of L beams is selected from oversampled 2D DFT beams and L can be set from L e {2 _f 3, 4, 6}-and the beam selection is wideband Is done in For W2, the L beams selected at W1 are combined with W2. In W2, subband reporting on phase quantization of the beam's combining coefficients is based on QPSK and 8-PSK with respect to the phase quantization information.

Can be set in either way. Type II CSI Category II

Feedback in the channel covariance matrix corresponds to long-term and wideband. The quantized and / or compressed versions of the covariance matrix are reported to the UE. The quantization and / or compression is based on a set of M orthogonal basis vectors. It may also be reported including an indicator for the M basis vectors, along with the set of coefficients.

The following schemes can be considered to reduce feedback overhead of Type II CSI. In one example, compression based on DFT may be considered. The precoder for a layer is a matrix of size PxN ₃

Can be represented. here ,

P can be expressed as P = 2N ₁ N ₂ , where P is equal to the number of dimensions of the spatial domain and N ₃ corresponds to the number of dimensions of the frequency domain (FD). Compression in the spatial domain (SD) is selected from the basis vectors of L spatial domains (2L total polarization), and the basis vectors use the following equation (5). Can be done in a compressed manner.

[Equation 5]

From here,

Corresponds to orthogonal DFT vectors of N ₁ N _{2 X} 1.

The input axis in the frequency domain (FD) may be represented by Equation 6 below.

[Equation 6] 2019/208992 1 »（： 1/10 2019/004836

45

W _f = [, (This,, W _f (2L 一 1)]

Where M ^) ni / / _{fci i "} . 八 Ni ᅴ, where

Orthogonal DFT vectors of yv ₃ xl of magnitude for component i = 0, ..., 2L-1. {Mi} corresponding to the number of components in the frequency domain, or

Can be set.

In particular, in the case of implicit LC codebook feedback, it is also contemplated to combine (by size and / or phase) the beam into the gastric subband to maximize its performance. In this case, the magnitude of the total feedback reported is the number of combined beams and the combining coefficient.

The quantized amount increases linearly with the size capability of the subband, which places a large burden on the feedback overhead.

Accordingly, in the present specification, the CSI reporting over the combined beam information in the wideband and / or the channel property in the subband is utilized by utilizing the angular property of the radio channel between the base station and the terminal. We propose an efficient codebook design method that reduces head. Here, among various methods of acquiring angular information of a radio channel, techniques for acquiring angular information based on uplink and / or downlink reference signals (i.e. As an example, the present disclosure proposes a technique and a signaling procedure for achieving the above object by using information related to channel sparsity characteristics occurring in an ultrahigh-frequency massive MIMO wireless communication environment. The terminal may receive configuration information related to CSI from the base station, and then the terminal may receive a reference signal (eg, CSI-RS) from the base station. Angle information may be calculated using at least one of the information and / or the CSI-RS, and channel state information may be calculated based on the calculated angle information and the CSI-RS. In addition, the calculated CSI can be reported to the base station. In the following description, the channel state information (CSI) is described based on a linear combination codebook, but it is a matter of course that other channel state information (CSI) types can be extended.

In the embodiments described below, in order to measure and / or calculate the CSI, the terminal receives a specific reference signal (RS) (for example, CSI-RS, etc.) configured for the CSI measurement and / or calculation from the base station. The case is assumed. The UE may measure (and / or calculate) CSI using a specific RS received by the UE, and may be configured to report the CSI to the base station (in a feedback format).

In addition, the embodiments and / or methods described below are merely divided for convenience of description, and the configuration of any embodiment may be substituted with the configuration of other embodiments and / or methods, or may be applied in combination with each other. Method 1) reporting angle information

In detail, a method for reporting a part or all of angular information of a radio channel to a base station by using a reference signal (RS) (for example, CSI-RS) received from a base station see.

The angle information reported by the terminal to the base station may include the following content.

Signal direction (s) 0 2019/208992 1 »（： 1/10 公 019/004836

47

Spatial rotation parameter

The number of beams in the transformation matrix (e.g. DFT matrix, pre-def ined basis) and the index of the beam

When the terminal reports the angle information to the base station, the angle information may be configured to be reported periodically (periodic), aperiodic (aperiodic), or semi-persistent. Method 2) Delivery and / or setting method related to CSI

In addition, the base station may transmit configuration information (configuration information) related to the CSI (downlink) to the terminal, the configuration information may include at least one of the following information.

i) Beam information of base station according to angular information

ii) transformation matrix information for angular information estimation

iii) spatial rotation matrix information for angular information estimation

iv) total payload size for CSI reporting

The beam information of the base station according to the angular information may be represented by an oversampling factor (ol, o2, etc.), the number of combining beams, the heading, the index of the corresponding beam, and the like. Information may include In addition, the beam information may include priority information on the beam. In addition, the beam information, the terminal is a space to the base station It may also include information for setting whether to report a rotation parameter.

Hereinafter, examples of a method of setting configuration information related to the CSI will be described.

As an example, a method of constructing a linear combination (LC) codebook (hereinafter referred to as an LC codebook) will be described.

Specifically, may correspond to w, = [ ^B, which corresponds to the information of the wideband attribute of the LC codebook ^, and may be configured in the form of a block diagonal matrix.

B ₂ ”is contained in the block diagonal matrix

Can be defined, b _i _; (ll L may correspond to the 2D and / or ID DFT beams represented in Equation 3. In addition, L represents the number of DFT beams that are linear combined. For example, the value of L is L = 2, 3, 4, etc., and this value can be promised by the base station and the terminal in advance. You can also give feedback.

The DFT beam indexes corresponding to b _u may be arranged in ascending or descending order according to the position of a column of the DFT matrix. Alternatively, the data may be selected and set based on the order of major influence on the channel information configuration based on angular information. As a specific example, in the situation where N _T = 32 and L = 4, b _u may be set to a value corresponding to the column indexes 3, 7, 15, and 27 of the DFT matrix, and 15 may be set according to the priority of the beam. , 3, 27, 7 may be set to a value corresponding to.

As another example, to calculate the angle information of the terminal, the base station transmits to the terminal Look at the transformation matrix information.

Significant values of channel information according to channel sparsity may mean features that are concentrated in a specific angular domain or a specific region of the channel covariance matrix. Significant channel information in the baby may mean information in which the size of the corresponding channel information element is greater than or equal to a specific reference value. Therefore, if the channel angular property between the base station and the terminal is known, channel information can be estimated with a high level of accuracy while reducing feedback overhead. In the present invention, the above principle can be used. Valid values of the channel information may be influenced according to properties of a transformation matrix (eg, DFT matrix, orthogonality) with respect to the actual channel matrix. Accordingly, the base station may instruct and / or set itself to share information about the transformation matrix with the terminal. Alternatively, the base station may set the terminal to use a predefined matrix as a transformation matrix.

Specific examples of the method of configuring the above-described transformation matrix may be as follows.

For example, the transformation matrices can be represented by and T ₂ , and the channel information matrix can be represented by X (M by K). In this case, the converted

It can be expressed as. In this case, the size of the transformation matrix may vary depending on the size of the channel information matrix X, and the channel information matrix X may be a covariance matrix of the channel or the channel itself. For example, M by M

DFT matrix), M by M size transformation matrix T ₂ (e.g. DFT matrix).

Based on the channel information of the matrix transformed through the transformation matrix, the CSI report (ie, feedback) of the terminal may be classified according to a method instructed by the terminal or the base station. have. For example, the UE may use the angular domain shape in the angular region of the channel covariance matrix by performing a DFT operation on the transform matrix and T ₂ for CSI reporting. Alternatively, the terminal may apply a steering matrix to the AoA / AoD and use it for CSI immediateization and / or calculation. In this case, it may be necessary to explain whether each call matrix is reflected. For example, when reflecting the adjustment matrix, setting and / or instruction on the transmitter and / or receiver side may be required for the corresponding angle value (s) and the matrix shape reflecting the adjustment matrix. On the other hand, if it does not reflect the adjustment matrix, it may be set to a value such as an identity matrix.

In addition, as mentioned above, the measurement of the channel state information in the Massive MINIO environment is the main angle (angle) and angle spread (signal path) of the signal path of the reference signal (RS) between the base station and the terminal ( may be affected by angular spread. Therefore, angular information on the signal between the terminal and the base station

The transformation matrix may be constructed by extracting a specific column of the transformation matrix aligned in a similar direction.

As another example, a method of performing a spatial rotation operation together with a DFT operation will be described.

In constructing the actual channel information, we use the low-rank characteristic according to _/ channel sparsity to extract the characteristics of the main direction with respect to the signal strength as angular information, and to send the channel information more concisely and with high accuracy. . That is, for accurate channel information estimation, it may be necessary to accurately reflect the characteristics of the signal path and the angle spread between the base station and the terminal. With multiple antennas 2019/208992 1 »（： 1/10 公 019/004836

Even though the finite beam direction represented by the DFT matrix may cause errors in the direction of the actual radio channel, the spatial rotation along with the DFT motion F is compensated for.

By performing more accurate angle estimation may be possible. In addition, the channel sparsity can be improved by reducing the magnitude of the angle diffusion.

Specifically, channel information to which the DFT operation and spatial rotation are applied may be configured as shown in Equation 7 below.

[Equation 7]

In Equation 7, p _ki denotes the complex gain of the corresponding sub-channel, and 0 ( ₍ |> _k ) = diag {(l, 中^k ,, eK ^NT - ¹⁾ ) Represents the spatial rotation matrix and ' ^e represents the spatial rotation matrix

Represents a spatial rotation parameter.

In this case, a (0) is affected by the antenna structure as an array manifold vector. In particular, it shows the shape of the neck and shape of ULA (Uniform Linear Array), and _d is the distance between antennas.

Where A represents the wavelength of the signal.

Further, S a (0 _k4 ) represent sub-channels in the beam-space and are orthogonal to each other. For example, in a ULA environment, _/ a (0 _{k, i} ) may correspond to a specific column of the DFT matrix. Method 3) CSI Reporting Method

Upon receiving the configuration information related to the CSI (downlink) as described above from the base station, the terminal uses one or more of the configuration information related to the CSI to transfer some or all of the following channel state information (CSI) to the base station. Report (i.e. feedback). The channel state information may include information about an LC codebook.

-Spatial rotation parameter information

-Number of beams and corresponding index of the transformation matrix

Quantized / Un-quantized beam combining coeff icient (s)

In addition, the channel state information may include parameter resolution information according to payload size. Alternatively, the channel state information may include angle information of the downlink channel. In addition, the angle information may include information such as A _O D (S), the angle spread. In addition, the angle information may be reported to the base station when the feedback of the spatial rotation parameter is set.

Hereinafter, operations related to the above-described CSI reporting will be described in detail. (Method 3-1) As described above, through the transformation matrix, sparsity of channel information in the wireless situation under consideration can be secured, and various channel information can be obtained by utilizing characteristics represented by significant values in sparse channel information. The required value can be calculated.

For example, a method of transforming and using a channel covariance matrix into a low-dimensional matrix may be considered.

In this method, the angular information (angular inforiaation) to grasp the characteristics of the base station beam and the terminal in the angular domain (angular domain) By utilizing, the terminal may select a column indicating the beam direction in the transformation matrix. Thereafter, the terminal may report to the base station the index of the selected column and the number of columns in the transformation matrix known to the base station and the base station. In addition, the terminal may extract channel characteristics of the angular region in the downlink by using the downlink and / or uplink reference signal (RS). In addition, the terminal may be used when calculating the CSI to feed back the angle information, it may be reported to the base station.

(Method 3-2) In addition, as described above, the UE may calculate a spatial rotation parameter for further improving the sparsity of the channel along with the DFT operation to reduce the feedback overhead, and report the result to the base station. have. The base station may restore the actual channel information by using the spatial rotation parameter value received from the terminal in a spatial rotation matrix previously promised by the base station and the terminal.

For example, prior to configuring a channel covariance matrix C = h _k h _k ^H to be fed back using the CSI-RS received by the UE, the UE internally has a spatial rotation parameter. )

To a specific resolution or specified method

Can be set. The channel covariance matrix C 'to which the spatial rotation 4> (0 _iter ) and the DFT operation are applied based on each set spatial rotation parameter value may be expressed by Equation 8 below.

[Equation 8]

At this time, in the modified channel covariance matrix (s) as above, The coefficients coefficient ñ may be assumed to be valid values, and the number thereof may be represented by n ((0 _iter ). The terminal may search for one-dimensional spatial rotation parameter 0 where n (C '( _it „)) is the smallest. Calculate through (one-dimensional search), and arrange space rotation

Report to the base station. In addition, the UE may report a value for the corresponding DFT beam index (es) to the base station at this time. By reporting the calculated spatial rotation parameter to the base station, the terminal can be set so that the base station has the same spatial rotation matrix. Thereafter, the base station can restore the channel covariance matrix C using the set spatial rotation matrix.

The spatial rotation parameter information corresponding to the new CSI report (ie, feedback) may be reported in subband CSI in consideration of frequency selectivity in terms of performance gain. Or, it may be reported as a wideband CSI in consideration of a payload side. Or, it may be reported as a combination of wideband CSI and subband CSI. For example, rough information corresponding to 4 bits may be reported in wideband CSI, and information corresponding to lbit may be reported in subband CSI.

(Method 3-3) Also, the information on the LC codebook may include information related to the precoding matrix. A process of acquiring channel information by a base station fed back from the terminal with channel state information including information on the LC codebook may be as follows. This is merely an example and may be applied to other feedback schemes.

For example, in detail, a method of setting beam grouping and / or beam combining in a Wi-matrix having a wideband property is specifically described. 2019/208992 1 »(： 1/10 公 019/004836

55 corresponds to wideband information in the codebook. In the present invention, for ease of explanation,

I will describe the case. However, this is only for convenience of explanation of the invention,

It does not limit the technical spirit of the invention. At this time, for the spatial rotation parameter ⁽ f> Zl) for each of the beams described above in the method 3-2, the spatial rotation matrix yaw may be configured as in Equation (9).

[Equation 9]

When the spatial rotation consisting of the spatial rotation matrix R is applied to the W1 to which the beam coupling is applied, it can be expressed as in Equation (10).

[Equation 10]

From this,

The spatial rotation is applied to the matrix, and it can be confirmed from Equation 11 that candidates are wideband beams constituting ¾ 3 3: 1: £ 3:! [Equation 11] [fl fw _r ] = [中 ⑷-中 (0) fw _r ]

That is, a result of applying spatial rotation to a column of each DFT matrix may be obtained, and a covariance matrix CT may be configured based on this. In this case, the number of beams may be reduced according to the degree of sparsity of the channel as compared to the number of beam candidates set by the base station, and the index of the column of the corresponding DFT matrix may also be changed. Therefore, the UE may report the changed L and DFT column indexes to the base station. Alternatively, the terminal may recommend L and DFT column indexes to the base station. For example, the terminal may transmit information on the preferred L and DFT column indexes to the base station.

In addition, by using the above-described method of setting up beam grouping and / or beam combining of Wi, a higher accuracy is utilized by utilizing linear combining through ¾ having sub-bend properties for the combined beams. It looks at how to generate a beam having a.

For example, the codebook for 13 words <1 may be expressed as Equation 12. This is just one example and can of course also be applied to codebooks for other chunks.

[Equation 12]

In Equation 12, the matrix is a general form of a matrix representing subband attributes in the LC codebook, and a combining coefficient parameter. It can consist of c and 0. Where c represents an amplitude value and 0 represents a phase value. The terminal may report the combined coefficient parameters collectively or independently to the base station. Alternatively, the terminal may set a parameter promised in advance between the terminal and the base station as a base station.

Specifically, the coupling coefficient parameters C and 0 may be set as in the examples below.

As an example, a case of performing linear combining (LC) by adjusting the size of each beam may be considered. In this case, the number of bits used for reporting (ie, feedback) may be determined according to the method of quantizing c and / or the degree of quantization. For example, it is basically set to {0,1} or {0.5,1} for 1-bit quantization, and can be quantized by mapping at uniform intervals according to the number of bits. Alternatively, since the pan direction having the main influence on the channel is set through the spatial rotation matrix, {0.75,1} or 1 may be set to the beam having the main influence on the channel, and the remaining beams may not be selected. Alternatively, the remaining resolution except for the beam that has a major influence on the channel may be mapped to {0,0.5} or {0,0.25} to increase the combining resolution for the same bit allocation.

In addition, all L beams set (or combined) may be used, or the number of beams to be used for combining may be indicated and / or set to a specific value to perform linear combining. In particular, as can be seen from the above, when the optimized spatial rotation can be applied to set the beam in the direction corresponding to the angular characteristics of the channel between the terminal and the base station, while reducing the number of beams are coupled to the power (power) The loss is more effective.

The approach described above can be applied in a similar manner to quantization of phases.

For example, the terminal may perform quantization of the phase by dividing the angle uniformly by a given bit with respect to the starting value and the range of the setting angle. Alternatively, as described above, since the beams having a major influence on the channel between the base station and the terminal may be selected by reflecting a spatial rotation matrix R to W1 having a wideband property, the influence on the phase value 0 Rather, the method of quantizing the magnitude value c with a high resolution may be preferred. As a specific example, when the quantization payload for one element of W2 is fixed, the number of bits may be allocated at the same ratio for _c and 0, or the number of bits corresponding to c may be allocated asymmetrically. . As described above, when linear combining is performed on beams in a spatial domain (SD) to set the actual radio channel to be aligned in the configured direction, L beams that are previously set or indicated are A codebook with high accuracy can be constructed with L '(<L) beams. This can be efficient in reporting the beam index and has an effect of reducing the number of combining coefficient (s) corresponding to the subband CSI reporting. In addition, when the terminal performs spatial rotation on a range of SD basis beams using a spatial rotation parameter, a total of 21 combining coefficients for the range set based on the angle information. On that beam Can report. Alternatively, the terminal may report to the base station by differentially applying the quantization of the coupling coefficients by using the priority of the corresponding beam. Accordingly, as described above, not only can the overall feedback payload size be reduced, but also it is possible to effectively set different coupling coefficients for quantization and transmission for a given payload size. The effect obtained in the present invention is not limited to the above-mentioned effects. At this time, the reporting of information (eg, angular information and / or CSI, etc.) related to the method (s) proposed in the present specification may be performed by performing a report on every channel measured in the time domain and / or the frequency domain. It may be performed in a short-term manner or may be performed in a long-term manner in which reporting is performed at intervals of a specific duration. In addition, the method (s) proposed herein feeds back a channel (ie, channel state information, CSI) using AoD, AoA, etc. based on two-dimensional (2D, 2D) channel modeling. The method (s) is extended to three-dimensional (3D) channel modeling, but may also be applied to channels considering zenith angles of departure (ZoD) and zenith angles of arrival (Zoa). Of course.

In particular, from the shape of an unformed linear array (ULA) that considers the existing antenna array signal process (NGA) method, _/ the shape of the antenna of two-dimensional form (e.g., a uniform planar array (UPA)) To be considered 0 2019/208992 1 ＞（： 1710 技 019/004836

60 can. In this case, a channel considering both horizontal and vertical information may be expressed by forming a Kronecker product as shown in Equation 13 below.

[Equation 13]

Here, the _/ 2D array manifold vector a (0 0 _j ) and the spatial rotation matrix 巾 (, 4) may be defined as Equation _{1 4} below.

(Equation 14) a Example 0k, j) ^{= a} h (0k, i) ® ^a v (0k, j)

⁽ K ，小於 =: 巾 () 效^o ( ⁽ ½)

That is, the two-dimensional array manifold vector may be configured through each array manifold vector assuming ULA in a horizontal and vertical environment. In addition, horizontal and / or vertical DoA values and ¾ may be estimated through UL channel information.

Similarly, spatial rotation matrices can also be constructed utilizing values in the horizontal and / or vertical angle regions. In addition, apart from the antenna structure, the spatial rotation matrix may be constructed based on N _T one- or two-dimensional DFT beams or specific orthogonality.

17 is a CSI to which an embodiment proposed in the present specification may be applied. An example of a signaling procedure between a base station and a terminal for feedback is shown. 17 is merely for convenience of description and does not limit the scope of the present invention. Referring to FIG. 17, it is assumed that a terminal and a base station operate based on the above-described methods 1), 2), and 3). That is, the procedure shown in FIG. 17 shows an example of a method of reducing feedback overhead while increasing the accuracy of CSI feedback by using angle information 5.

First, the base station may transmit configuration information related to the CSI to the terminal (S1710). For example, the configuration information may be based on method 2 described above. As a specific example, the configuration information related to CSI may include transform matrix information for estimating L0 angle information, spatial rotation matrix information, and total payload size information for CSI feedback. In addition, the configuration information may include beam information of the base station according to the angle information. The beam information of the base station according to the angle information may include information such as an oversampling factor, the number of combined beams of the base station and the index of the corresponding beam.

_{15, the} terminal receives the configuration information from the base station, and then a reference signal (for example:

CSI-RS) may be received (S1720).

The terminal may calculate angle information (¾ngular information) based on at least one of the CSI-RS and / or the configuration information received from the base station (S1730). For example, the calculation of the angle information may be based on the above-described method 1), method 3) 20 and the like. As a specific example, the angle information may include information about at least one of i) the direction of the signal, ii) the angle spread, iii) the spatial rotation parameter and / or iv) the number of beams of the transformation matrix and the corresponding index. The terminal may measure and / or calculate downlink channel state information (CSI) including information on a linear combination (LC) codebook (hereinafter, referred to as an LC codebook) based on the configuration information and the angle information. There is (S1740). For example, the calculation of the channel state information may be based on the above method 3). As a specific example, a method of calculating information about the linear combination codebook may be as follows. For example, according to the aforementioned method 3) (methods 3-1 to 3-3), the terminal calculates the index of the beam and the number of beams by applying spatial rotation to the beam group and / or the combination You can report it. In addition, the terminal may calculate and report a coupling coefficient of W2 having a subband channel attribute based on the angle information.

The terminal may report the channel state information to the base station (S1750). 18 shows another example of a signaling procedure between a base station and a terminal for CSI reporting to which an embodiment proposed in the present specification can be applied. Figures are merely for convenience of description and do not limit the scope of the invention. In FIG. 18, the terminal may calculate angle information (S1810). For example, the calculation of the angle information may be based on the above-described methods 1) and 3). As a specific example, the angle information may be calculated based on at least one of configuration information for CSI feedback and / or CSI-RS received by the terminal from the base station. This may be considered to correspond to steps S1710 to S1730 of FIG. 17. Accordingly, detailed descriptions that overlap are omitted.

Thereafter, the terminal may transmit the calculated angle information to the base station (S1820). The base station rotates the space appropriate to the beam state of the base station based on the received angle information Parameter setting information may be transmitted to the terminal (S1830). For example, the spatial rotation parameter setting information may be based on the method 2) described above. As a specific example, the spatial rotation parameter setting information may include beam information of the base station, and the beam information of the base station may include an oversampling factor, the number of combined beams, and index information of the corresponding beam. As another example, the spatial rotation parameter setting information may include information and / or angle information about a beam preferred by the base station.

The terminal may measure and / or calculate channel state information based on the spatial rotation parameter setting information received from the base station (S1840), and report the channel state information to the base station (S1850). As mentioned earlier, this procedure is based on AoD,

Although a method of feeding back a channel (ie, channel state information, CSI) using AoA, etc. is described, it can be extended to 3D channel modeling and applied to a channel considering ZOD, ZoA, and the like. 19 shows an example of an operation flowchart of a terminal performing CSI reporting in a wireless communication system to which the method proposed in this specification can be applied. 19 is merely for convenience of description and does not limit the scope of the present invention.

Referring to FIG. 19, the terminal and the base station are the methods 1), 2), described above in this specification.

3) It is assumed that the CSI reporting (ie, feedback) is performed based on the above.

First, the terminal is connected to the downlink channel (downlink channel) 2019/208992 1 »（： 1/10 公 019/004836

64) configuration information related to the CSI may be received (S1910). For example, the configuration information may be based on the method 2) described above. As a specific example, the configuration information may include transform matrix information for estimating angle information of the terminal, information about a spatial rotation matrix, and the like. In addition, as an example, the configuration information may include information related to the CSI reporting setting. In this case, the configuration information may be delivered through semi-static signaling (eg, RRC signaling, etc.).

Thereafter, the terminal may receive a reference signal (eg, CSI-RS) for the CSI report from the base station (S1920).

Thereafter, the terminal may calculate angle information based on at least one of the configuration information and / or the reference signal (for example, CSI-RS) (S1930). For example, the calculation of the angle information may be based on the above-described method 1), method 3), and the like. As a specific example, the angle information may include information on at least one of i) the direction of the signal, H) the angle spread, iii) the spatial rotation parameter, and / or iv) the number of beams of the transformation matrix and the corresponding index.

Next, the terminal may perform CSI calculation and reporting to the base station based on the configuration information and the angle information (S1940). For example, the CSI report may include information on a linear combination codebook. The CSI may include information such as a spatial rotation parameter, the number of beams of a transformation matrix, a corresponding index, and a coupling coefficient of quantized and / or quantized beams.

For example, the CSI calculation may be based on the method 3) described above. As a specific example, the calculation of the CSI, the terminal is the configuration information and / or the CSI-RS Calculating angle information including a spatial rotation parameter based on at least one of the following; The information on the LC codebook may be calculated based on the angle information and the setting information. As another example, the calculation of the spatial rotation parameter may include: setting, by the terminal, the spatial rotation parameter internally at a specific resolution or method; Deriving a channel covariance matrix to which a spatial rotation and a DFT operation are applied based on the set spatial rotation parameter; And a spatial rotation parameter in which coefficients greater than or equal to a specific threshold value are assumed as valid values in the channel covariance matrix, and the number of valid coefficients is smallest.

Calculating a through a one-dimensional search; Through the spatial rotation parameter 4 _> ^ 1 ° 1 can be calculated.

In addition, as an example, the UE may report the CSI to the base station including the spatial rotation parameter, and may also report a value for the DFT beam index (es) corresponding to the calculation of the spatial rotation parameter to the base station. In this way, the base station and the terminal may be set to have the same spatial arm matrix. Thereafter, the base station can restore the channel covariance matrix using the set spatial rotation matrix. In addition, after the CSI report is performed, the terminal receives data from the base station according to data scheduling information of the base station. can do.

2 ◦ shows an example of an operation flowchart of a terminal performing a CSI report in a wireless communication system to which the method proposed in this specification can be applied. 20 is only for convenience of description, it is intended to limit the scope of the invention \ ¥ 0 2019/208992 1 »（1 ^ 1 {2019/004836

66 No.

Referring to Figure 2◦, the terminal may calculate the angle information (32010). For example, the calculation of the angle information may be based on the above-described method 1), method 3), and the like. As a specific example, the angle information may be configuration information for feedback 031 received by the terminal from the base station and / or

Can be killed based on at least one of the. This may correspond to a procedure corresponding to steps 31910 to 31930 in FIG. 19. Accordingly, detailed descriptions that overlap are omitted. The setting information may include transformation matrix information and spatial rotation matrix information for calculating the angle information.

Thereafter, the terminal may report the angle information to the base station (32020). At this time, the report may also be performed.

Thereafter, the terminal may receive spatial rotation parameter setting information from the base station (eg, 3203. For example, the spatial rotation parameter setting information may be set based on the giga-degree information, an oversampling factor, combined It may include information about the beam of the base station, such as the number of beams and the index of the beam, etc. As another example, the spatial rotation parameter setting information may include information and / or angle information about the beam preferred by the base station. have.

The terminal may measure and / or calculate 031 based on the spatial rotation parameter setting information and report it to the base station (32040). 21 is a wireless communication system to which the method proposed in the present specification can be applied.

An example of an operation flowchart of a base station receiving a report is shown. Degree 2019/208992 1 »（： 1 ^ 112019/004836

67

2-1 is merely for convenience of description and does not limit the scope of the present invention.

Referring to FIG. 21, it is assumed that a terminal and a base station perform CSI reporting (ie, feedback) based on the above-described methods 1), 2), 3), and the like.

5 First, the base station may transmit configuration information (configuration information) # associated with the CSI (for the downlink channel) (S2110). For example, the configuration information may be based on the above-described method 2). As a specific example, the configuration information may include transform matrix information for estimating angle information of the terminal, information about a spatial rotation matrix, and the like. Alternatively, the configuration information may include information on the total payload size for CSI reporting of the 0 terminal. Alternatively, the configuration information may include beam information of the base station according to the angle information transmitted by the terminal. The beam information of the base station may include an oversampling factor, the number of combined beams of the base station, index information of the corresponding beam, and the like. At this time, priorities for the combined beams may be designated. Also, as an example, 5 the configuration information may include information related to the CSI reporting setting. In this case, the configuration information may be delivered through semi-static signaling (eg, RRC signaling, etc.).

Thereafter, the base station may transmit at least one reference signal (eg, CSI-RS) for the CSI report to the terminal (S2120).

After 0, the base station can receive the angle information from the terminal (S2130). For example, the angle information may be derived based on the method 1) described above. As a specific example, the angle information is a CSI-RS received by the terminal from the base station And / or based on at least one of the CSI related configuration information.

Next, the base station may transmit the spatial rotation parameter setting information to the terminal based on the angle information (S2140). For example, the spatial rotation parameter setting information may be based on the method 2) described above. As a specific example, the spatial rotation parameter setting information may include information about the beam of the base station such as an oversampling factor, the number of combined beams, and the index of the corresponding beam. As another example, the spatial rotation parameter setting information may include information and / or angle information about a beam preferred by the base station. In addition, when UL-DL channel reciprocity is established, the above-described step S2130 and / or step S2140 may be omitted.

Thereafter, the base station may receive a CSI report from the terminal (S2150), for example, the CSI may be calculated based on the above-described method 3). As a specific example, the CSI may be calculated based on the spatial rotation parameter setting information. Also, as an example, the CSI report may include information about the LC codebook, spatial rotation parameter information, and the like. In this case, since the contents related to the CSI calculation are the same as those described with reference to FIG. 19, detailed descriptions thereof will be omitted.

In addition, the base station receiving the CSI report may calculate data scheduling and single user (SU) / multi user (MU) -MIMO precoding in consideration of the channel state of the terminal. The base station may transmit the calculated precoding data and RS for decoding of the data (eg, DMRS, yoi) to the UE. Apparatus to which the present invention may be applied 2019/208992 1 * (: 171 ^ 019/004836

Below 69, downlink (DL) means communication from the base station to the terminal, and uplink (UL) means communication from the terminal to the base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal and a receiver may be part of a base station. The base station may be represented by the first communication device and the terminal by the second communication device. A base station (BS) is a fixed station (Node), Node B, evolved-NodeB (eNB), Next Generation NodeB (gNB), base transceiver system (BTS), access point (AP), network (5G). Network), AI (Artificial Intelligence) system / module, RSU (road side unit), robot, drone (Unmanned Aerial Vehicle, UAV) _f

It can be replaced by terms such as AR (Augmented Reality) device or VR (Virtual Reality) device. In addition, a terminal may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), and an advanced mobile (AMS). Station), WT (Wireless terminal),

MTC (Machine-Type Communication) apparatus, M2M (Machine-to-Machine ) equipment, D2D (Device-to-Device ) unit, a vehicle (vehicle), RSU (road side unit) r robot (robot), AI (Artificial Intelligence Module, drone (Unmanned Aerial Vehicle, UAV), Augmented Reality (AR) device, and Virtual Reality (VR) device.

FIG. 22 illustrates a block diagram of a wireless communication apparatus to which the methods proposed herein may be applied. Referring to FIG. 22, a wireless communication system includes a base station 2210-and a plurality of terminals 2220-located in a base station area.

The base station and the terminal may each be represented by a wireless device.

The base station 2210 includes a processor 2211, a memory 2212, and an RF unit 2213. The processor 2211 implements the functions, processes, and / or methods proposed in FIGS. 1 to 21. Layers of the air interface protocol may be implemented by a processor. The memory is connected to the processor and stores various information for driving the processor. The RF unit 2213 is connected to the processor to transmit and / or receive a radio signal. For example, the processor 2211 may control the RF unit 2213 to transmit configuration information related to the CSI for the downlink channel to the terminal (S2110). In addition, the processor 2211 may control the RF unit 2213 to transmit at least one CSI-RS for the CSI report to the terminal (S2120). In addition, the processor 2211 may control the RF unit 2213 to receive a CSI report calculated by the terminal based on the configuration information and the angle information from the terminal (S2150). In this case, the angle information may be calculated by the terminal based on at least one of the configuration information and / or the CSI-RS. In addition, in the case of the base station receiving the CSI report, the processor 2211 may calculate data scheduling and single user (SU) / multi user (MU) -MIMO precoding in consideration of the channel state of the terminal. The processor 2211 is calculated by controlling the RF unit 2213 2019/208992 1 ＞（1 '/ 10.2019 / 004836

71 Precoding Data and Decoding of Data

110 may be transmitted to the terminal.

The terminal includes a processor 2221, a memory 2222 ñ and an RF unit 2223. The processor 2221 ñ implements the functions, processes, and / or methods proposed in FIGS. 1 to 21 above. The layers may be implemented by the processor 2221. The memory 2222 is connected to the processor 2221 to store various information for driving the processor 2221. The RF unit 2223 is a processor 2221. And transmit and / or receive a radio signal.

For example, the processor 2221 may control the RF unit 2223 to receive configuration information related to the CSI for the downlink channel from the base station (S1910). In addition, the processor 2221 may control the RF unit 2223 to receive the CSI-RS for the CSI report from the base station (S1920). In operation S1930, the processor 2221 may calculate angle information based on at least one of the configuration information and / or the CSI-RS. In addition, the processor 2221 may calculate a CSI to be fed back based on the received setting information and the angle information (S2240). Specifically, the CSI report may include information on a linear combination codebook. In this case, the information fed back by the terminal (ie, CSI) may be a spatial rotation parameter, the number of beams of the transformation matrix, and the corresponding information. It may include information such as an index, a coupling coefficient of the quantized / unquantized beam, and the like.

In particular, with regard to calculating the spatial rotational parameters, the processor 2221 may preset the spatial rotational parameters in a specific resolution or manner. to the next The processor 2221 may plot a channel covariance matrix to which a spatial rotation and a DFT operation are applied based on the set spatial rotation parameter. At this time, the processor 2221 assumes coefficients that are greater than or equal to a certain threshold value in the channel covariance matrix as valid values, and a spatial rotation parameter in which the number of valid coefficients is smallest.

Can be calculated through one-dimensional search.

In addition, the UE may report the CSI to the base station including the spatial rotation parameter, and at this time, the value of the corresponding DFT beam index (es) may be reported to the base station. Through this, the base station and the terminal can be set to have the same spatial rotation matrix. Thereafter, the base station can restore the channel covariance matrix using the set spatial rotation matrix. After the CSI report is performed, the terminal can receive data from the base station according to data scheduling information of the base station. have.

Further, with respect to the calculation of the CSI to be reported to the base station, the processor 2221 may determine the number of beams of the transformation matrix and corresponding indexes, the coupling coefficients of the quantized / unquantized beams, and the like based on the angle information such as the spatial rotation parameter. It is possible to calculate the information of. Thereafter, the processor 2221 may control the RF unit 2223 to report the calculated CSI feedback to the base station (S1940).

The memories 2212 and 2222 may be inside or outside the processors 2211 and 2221, and may be connected to the processor by various well-known means.

In addition, the base station and / or the terminal may have a single antenna or multiple antennas. 02019/208992 1 ^ / 10 技 019/004836

73

FIG. 23 is another example of a block diagram of a wireless communication apparatus to which the methods proposed herein may be applied.

Referring to FIG. 23, a wireless communication system includes a reporter station 2310 and a plurality of terminals 2320 located in a base station area. The base station may be represented by a transmitting device, the terminal may be represented by a receiving device, and vice versa. The base station and the terminal are a processor (processor, 2311,2321), memory (memory, 2314,2324), one or more Tx / Rx RF module (radio frequency module, 2315, 2325), Tx processor (2312, 2322), Rx processor ( 2313, 2323), antennas (2316, 2326). The processor implements the salping functions, processes and / or methods above. More specifically, in the DL (communication from the base station to the terminal), upper layer packets from the core network are provided to the processor 2311. The processor implements the functionality of the L2 layer. In the DL, the processor provides the terminal ² 320 with multiplexing, radio resource allocation between logical channels and transport channels, and is responsible for signaling to the terminal. The transmit (TX) processor 2312 implements various signal processing functions for the L1 layer (ie, the physical layer). The signal processing function enables the FEC (forward error correct 丄 on ñ ⁰ 1) at the terminal and includes coding ¾ interleaving. The encoded and modulated symbols are divided into parallel streams, and each stream is OFDM A physical channel that is mapped to a subcarrier, multiscaled with a reference signal (RS) in the time and / or frequency domain, combined together using an Inverse Fast Fourier Transform (IFFT) to carry a time domain OFDMA symbol stream. 2019/208992 1 »（： 1 ^ 1 ^{ 2019/004836

Create 74. The OFDM stream is spatially prenamed to produce a multi-spatial stream. Each spatial stream may be provided to a different antenna 2316 via a separate Tx / Rx module (or transceiver 2315). Each Tx / Rx module can modulate an RF carrier with each spatial stream for transmission. At the terminal, each Tx / Rx module (or transceiver 2325) receives a signal through each antenna 2326 of each Tx / Rx module. Each Tx / Rx module recovers information modulated onto an RF carrier and provides it to a receive (RX) processor 2323. The RX processor implements the various signal processing functions of layer 1. The RX processor may perform spatial processing on the information to recover any spatial stream destined for the terminal. If multiple spatial streams are directed to the terminal, it may be combined into a single OFDMA symbol stream by multiple RX processors. The RX processor uses fast Fourier transform (FFT) to convert the OFDMA symbol stream from the time domain to the frequency domain. The frequency domain signal includes a separate OFDMA symbol stream for each subcarrier of the OFDM signal. The symbols and reference signal on each subcarrier are recovered and demodulated by determining the most likely signal placement points sent by the base station. Such soft decisions may be based on channel estimate values. Soft decisions are decoded and deinterleaved to recover the data and control signals originally transmitted by the base station on the physical channel. Corresponding data and control signals are provided to the processor 2321.

The UL (communication from terminal to base station) is processed at base station 2310 in a manner similar to that described with respect to receiver functionality at terminal 2320. Each Tx / Rx module 2325 receives a signal via a respective antenna 2326. Each The Tx / Rx module provides the RF carrier and information to the RX processor 2323. The processor 2321 may be associated with a memory 2324 that stores program code and data. The memory may be referred to as a computer readable medium. 24 illustrates an example of a signal processing module structure in a transmission device. Here, signal processing may be performed in a processor of a base station / terminal such as the processors 2211 and 2221 of FIG. 22.

Referring to FIG. 24, a transmission device in a terminal or a base station includes a scrambler 2401, a modulator 2402, a layer mapper 2403, an antenna port mapper 2404, a resource block mapper 2405, and a signal generator 2406. can do.

The transmitting device may transmit one or more codewords. Coded bits in each codeword are scrambled by the scrambler 2401 and transmitted on the physical channel. The codeword may be referred to as a data string and may be equivalent to a transport block which is a data block provided by the MAC layer.

The scrambled bits are modulated into complex-valued modulation symbols by modulator 2402. The modulator 2402 may arrange the scrambled bits as complex modulation symbols representing positions on signal constellations by modulating the scrambled bits. There is no restriction on a modulation scheme, and m-Phase Shift Keying (m-PSK) or m-Quadrature Amplitude Modulation (m-QAM) may be used to modulate the pre-coded data. The modulator may be referred to as a modulation mapper. The complex modulation symbol may be mapped to one or more transport layers by a layer mapper 2403. Complex modulation symbols on each layer may be mapped by antenna port mapper 2404 for transmission on the antenna port.

The resource block mapper 2405 may map the complex modulation symbol for each antenna port to the appropriate resource element in the virtual resource block allocated for transmission. The resource block mapper may map the virtual resource block to a physical resource block according to an appropriate mapping scheme. The resource block mapper 2405 may assign a complex modulation symbol for each antenna port to an appropriate subcarrier and multiplex according to a user.

The signal generator 2406 modulates a complex modulation symbol for each antenna port, that is, an antenna specific symbol by a specific modulation scheme, for example, an Orthogonal Frequency Division Multiplexing (OFDM) scheme, thereby complex-valued time domain. An OFDM symbol signal can be generated. The signal generator may perform an inverse fast fourier transform (IFFT) on the antenna specific symbol, and a cyclic prefix (CP) may be inserted into the time domain symbol on which the signal is performed. The OFDM symbol is transmitted to the receiving apparatus through each transmit antenna through digital-to-analog conversion, frequency upconversion, and the like. The signal generator may include an IFFT module and a CP inserter, a digital-to-analog converter (DAC), a frequency uplink converter, and the like.

25 shows another example of a structure of a signal processing module in a transmission device. Here, the signal processing may be performed in a processor of the terminal / base station such as the processors 2211 and 2221 of FIG. 22. Referring to FIG. 25, a transmission device in a terminal or a base station may include a scrambler 2501, a modulator 2502, a layer mapper 2503, a precoder 2504, a resource block mapper 2505, and a signal generator 2506. Can be. The transmitting device may scramble the coded bits in the codeword by the scrambler 2501 for one codeword and then transmit the same through a physical channel.

The scrambled bits are modulated into complex modulation symbols by modulator 2502. The modulator may be arranged as a complex modulation symbol representing a position on a signal constellation by modulating the scrambled bit according to a predetermined modulation scheme. There is no restriction on the modulation scheme, and it includes pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PK (m-Phase Shift-Keying), or rri-QAM (m-Quadrature Amplitude Modulation) This can be used for modulation of the encoded data.

The complex modulation symbol may be mapped to one or more transport layers by the layer mapper 2503. Complex modulation symbols on each layer may be precoded by the precoder 2504 for transmission on the antenna port. Here, the precoder may perform pre-coding on the basis of transform precoding on complex modulation symbols. Alternatively, the precoder may perform precoding without performing transform precoding. Precoder 2504 stores the complex modulation symbol. The antenna specific symbols may be co-ordinated by the MIMO scheme according to the multiple transmit antennas, and the antenna specific symbols may be distributed to the corresponding resource block mapper 2505. The output z of the precoder 2504 can be obtained by multiplying the output y of the layer mapper 2503 by the precoding matrix W of N × M. Where N is the number of antenna ports and M is the number of layers.

Resource block mapper 2505 maps the demodulation modulation symbol for each antenna port to the appropriate resource element in the virtual resource block allocated for transmission.

_''

The resource block mapper 2505 may assign a complex modulation symbol to an appropriate subcarrier and multiplex according to a user.

The signal generator 2506 modulates the complex modulation symbol in a specific modulation scheme, for example, the OFDM scheme, to complex-valued time domain.

Orthogonal Frequency Division Multiplexing (OFDM) symbol signals may be generated. Signal generator 2506 is configured for antenna specific symbols.

Inverse Fast Fourier Transform (IFFT) may be performed, and a cyclic prefix (CP) may be inserted into the time domain symbol on which the IFET is performed. The OFDM symbol is transmitted to the receiving apparatus through each transmit antenna through digital-to-analog conversion, frequency upconversion, and the like. Signal generator 2506 may include an IFFT module and a CP inserter, a digital-to-analog converter (DAC), a frequency uplink converter, and the like.

The signal processing of the receiver may be configured as the inverse of the signal processing of the transmitter. Specifically, the processor 2211, 2221 of the transmitting device decodes a radio signal received through the antenna port (s) of the transceiver from the outside and Perform demodulation. The receiving device may include a plurality of multiple receiving antennas, and each of the signals received through the receiving antenna is restored to the baseband signal and then restored to the data sequence originally intended to be transmitted by the transmission device through multiplexing and MIMO demodulation. . The receiver may include a signal recoverer for recovering the received signal into a baseband signal, a multiplexer for combining and multiplexing the received processed signals, and a channel demodulator for demodulating the multiplexed signal sequence with a corresponding codeword. The signal reconstructor, multiplexer, and channel demodulator may be configured as one integrated module or each independent module for performing their functions. More specifically, the signal reconstructor is an analog-to-digital converter (ADC) for converting an analog signal into a digital signal, a CP canceller for removing a CP from the digital signal, and a fast Fourier transform (FFT) to the signal from which the CP is removed. FFT module for outputting a frequency domain symbol by applying a, and may include a resource element demapper (equalizer) to restore the frequency domain symbol to an antenna specific symbol. The antenna specific symbol is restored to a transmission layer by a multiplexer, and the transmission layer is restored to a codeword intended to be transmitted by a transmitting device by a channel demodulator.

In the present specification, a wireless device includes a base station, a network node, a transmitting terminal, a receiving terminal,

.

Wireless devices, wireless communication devices, vehicles, vehicles with autonomous driving, unmanned aerial vehicles (AIV) _f AI (artificial intelligence) modules, robots, AR (Augmented Reality) devices, VR (Virtual Reality) devices, MTC devices IoT devices, medical devices, fintech devices (or financial devices), security devices, Climatic / environmental devices or other quaternary industrial revolutions or devices related to 5G services. For example, a drone may be a vehicle in which humans fly by radio control signals. For example, the MTC device and the IoT device are devices that do not require human intervention or manipulation, and may be smart meters, bending machines, thermometers, smart bulbs, door locks, various sensors, and the like. For example, a medical device is a device used to examine, replace, or modify a device, structure, or function used for diagnosing, treating, alleviating, treating, or preventing a disease, such as a medical device, a surgical device, ( In vitro) diagnostic devices, hearing aids, surgical devices, and the like. For example, a security device is a device installed to prevent a risk that may occur and to maintain safety, and may be a camera, a CCTV, a black box, or the like. For example, the fintech device is a device that can provide financial services such as mobile payment, and may be a payment device, a Point of Sales (POS), or the like. For example, the climate / environmental device may mean a device for monitoring and predicting the climate / environment. In the present specification, the terminal is a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), navigation, a slate PC, a tablet PC (tablet PC), ultrabook, wearable device (e.g., smartwatch, glass glass, head mounted display), foldable device And the like. For example, the HMD is a head-worn display device, which can be used to implement VR or AR. have. The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, it is also possible to combine the some components and / or features to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention 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 obvious that the embodiments can be combined to form a new claim by combining claims which are not expressly cited in the claims or by post-application correction.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and FFGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented as a module, a procedure, a function, or the like for performing the functions or operations described above. 2019/208992 1 »（： 1 ^ 1 {2019/004836

82 can be implemented. The software code may be stored in memory and driven by the processor. The memory may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

Industrial Applicability

In the wireless communication system of the present invention, a method for transmitting and receiving channel state information includes 30 system and 50 system.

The example is applied to a system), but it is possible to apply to various wireless communication systems.

Claims

2019/208992 1 * （： 1 ^ 1 {2019/004836 83】 Scope of claim

[Claim 1]

A method for a terminal to perform channel state information (CSI) reporting in a wireless communication system,

Receiving configuration information related to the CSI for a downlink channel from a base station;

Receiving a CSI-RS for the CSI report from the base station; Calculating angular information of the downlink channel based on at least one of the configuration information and / or the CSI-RS; And

By using the setting information and the angle information, the base station to the

Performing CSI reporting;

The CSI report includes information about a linear combination (LC) codebook based on the angular information.

[Claim 2]

The method of claim 1,

The configuration information may include transform matrix information for calculating the angular information, information about a spatial rotation matrix, information about a beam of the base station, and / or a total payload size for reporting the CSI ( total payload size) information.

[Claim 3] 2019/208992 1 1/10 公 019/004836

84 The method of claim 2,

The information on the range of the base station may include at least one of: i) an oversampling factor and / or ii) the number of combined beams and an index of the corresponding beam. Way

[Claim 4]

The method of claim 1,

The angle information may include i) the signal direction, ii) the angular spread, iii) the spatial rotation parameter and / or iv) the number of beams in the transformation matrix and the corresponding ( corresponding) at least one of an index of the beam.

[Claim 5]

The method of claim 4, wherein

Reporting the angular information to the base station, wherein the angular information is set to be reported periodically, aperiodic, or seiui-persistent.

[Claim 6]

The method of claim 5,

Receiving spatial rotation parameter setting information from the base station Include more,

The spatial rotation parameter setting information is set by the base station based on the angle information.

[Claim 7]

The method of claim 6,

And performing, by the base station, CSI reporting based on the spatial rotation parameter setting information.

[Claim 8]

The method of claim 1,

The information about the LC codebook includes information related to a precoding matrix including a first matrix and a second matrix.

And wherein the first matrix corresponds to a wideband channel attribute and the second matrix corresponds to a subband channel attribute.

[Claim 9]

The method of claim 8,

The first matrix is a spatial rotation matrix shared between the terminal and the base station.

based on the spatial rotation matrix,

The spatial rotation matrix is set based on the first spatial rotation parameter Characterized in that the method.

[Claim 10]

The method of claim 9,

The method for calculating the first spatial rotation parameter by the terminal includes: setting a second spatial rotation parameter;

Plotting a channel covariance matrix based on the second spatial rotation parameter; And

Calculate the first spatial rotation parameter based on the channel covariance matrix,

The first spatial rotation parameter is regarded as a valid value when the coefficient of the channel covariance matrix is equal to or greater than a specific threshold value, and the first spatial rotation parameter is calculated based on a value where the number of valid coefficients is ^' smallest ^'. Characterized in that the method.

[Claim 11]

The method of claim 8,

The first matrix includes DFT beam index information as a component,

The DFT beam index is set based on the order influencing the CSI reporting based on the angle information.

[Claim 12]

The method of claim 8,

The second matrix includes a combining coefficient for the LC codebook,

Said coupling coefficient being set based on said spatial rotation matrix.

[Claim 13]

A terminal for performing channel state information reporting in a wireless communication system, the terminal

RF (Radio Frequency) unit for transmitting and receiving radio signals,

A processor is functionally connected with the RF unit, wherein the processor,

Receive configuration information related to the CSI for a downlink channel from a base station;

Receive, from the base station, a CSI-RS for the CSI report;

Calculating angular information of the downlink channel based on at least one of the configuration information and / or the CSI-RS; And

Controlling the csi report to the base station by using the configuration information and the angle information;

The CSI report is characterized in that it comprises information on a linear combination (LC) codebook based on the angle information.

[Claim 14]

The method of claim 13,

And the processor controls the angular information to be reported to the base station periodically, aperiodic, or semi-persistent.

[Claim 15]

A base station for performing channel state information reporting in a wireless communication system, the base station

RF (Radio Frequency) unit for transmitting and receiving radio signals,

A processor is functionally connected with the RF unit, wherein the processor,

Transmitting configuration information related to the CSI on a downlink channel to a terminal;

Send a CSI-RS for the CSI report to the terminal; And

While controlling to receive the CSI report from the terminal,

At least one of the configuration information and / or the CSI-RS is used by the terminal to calculate angular information of the downlink channel;

The CSI report includes information about a linear combination (LC) codebook calculated based on the configuration information and the angle information. 2019/208992 1 »（： 1/10 公 019/004836

89

Characterized by a base station.