AU2018282270B2 - Method for reporting channel state information in wireless communication system and apparatus for the same - Google Patents

Abstract

[ABSTRACT] The present invention provides a method of reporting, by a user equipment (UE), channel state information (CSI) in a wireless communication system, the method comprising: receiving, by the UE and from a base station (BS), downlink 5 control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value nc r based on a number of symbols ' related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n - nc _r in a time domain that is to be used for the aperiodic CSI report; and transmitting, by the UE and to the BS, the aperiodic 10 CSI report in the slot n, based on the CSI reference resource being slot n - nc _r According to the present invention, CSI may be calculated by using the most recent A CSI-RS, and thereby the most recent CSI may be reported. 99

Description

METHOD FOR REPORTING CHANNEL STATE INFORMATION IN WIRELESS COMMUNICATION SYSTEM AND APPARATUS FOR THE SAME

[Technical Field]

[1] The present disclosure relates to wireless communication and, more

particularly, to a method for reporting Channel State Information (CSI) and an

apparatus for supporting the method.

[Background]

[2] Mobile communication systems have been generally developed to provide

voice services while guaranteeing user mobility. Such mobile communication

o systems have gradually expanded their coverage from voice services through data

services up to high-speed data services. However, as current mobile

communication systems suffer resource shortages and users demand even higher

speed services, development of more advanced mobile communication systems is

needed.

[3] The requirements of the next-generation mobile communication system may

include supporting huge data traffic, a remarkable increase in the transfer rate of

each user, the accommodation of a significantly increased number of connection

devices, very low end-to-end latency, and high energy efficiency. To this end,

various techniques, such as small cell enhancement, dual connectivity, massive

multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple

access (NOMA), supporting super-wide band, and device networking, have been

researched.

[3A] It is desired to address or ameliorate one or more disadvantages or

limitations associated with the prior art, or to at least provide a useful alternative.

[Summary]

[3B] According to the present invention there is provided a method of reporting, by

a user equipment (UE), channel state information (CSI) in a wireless communication

system, the method comprising:

receiving, by the UE and from a base station (BS), downlink control

information (DCI) related to an aperiodic CSI report that is to be performed by the UE

in a slot n;

determining, by the UE, a value ncQ,_ref based on a number of symbols Z'

related to a time for computing the CSI;

o determining, by the UE, a CSI reference resource as being a slot n - ncQi-ref

in a time domain that is to be used for the aperiodic CSI report; and

transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n,

based on the CSI reference resource being slot n - ncQi-ref,

wherein the value ncQi-ref is a smallest value greater than or equal to

msuchthattheslotfn- ncQref satisfies a valid downlink slot criteria, and

wherein - J isa floor function and N b is number ofsymbolsinone

slot.

[3C] According to the present invention there is further provided a user equipment

(UE) configured to report channel state information (CSI) in a wireless

communication system, the UE comprising:

a radio frequency (RF) module configured to transmit and receive radio

signals;

at least one processor; and

at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising: receiving, via the RF module and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value ncQ,_ref based on a number of symbols Z' related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n - ncQi-ref in a time domain that is to be used for the aperiodic CSI report; and o transmitting, via the RF module and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n - ncQi-ref, wherein the value ncQi-ref is a smallest value greater than or equal to

Z'/Nlmt such thattheslotfn- ncQref satisfies a valid downlink slot criteria, and

wherein[ Jis a floor function and Nslma is a number of symbols in one slot.

[Brief Description of the Drawings]

[4] Preferred embodiments of the present invention are hereinafter described, by

way of non-limiting example only, with reference to the accompanying drawings, in

which:

[5] FIG. 1 illustrates one example of the overall system structure of an NR to

which a method proposed by the present specification may be applied.

[6] FIG. 2 illustrates a relationship between an uplink frame and a downlink

frame in a wireless communication system to which a method proposed by the

present specification may be applied.

[7] FIG. 3 illustrates one example of a resource grid supported by a wireless communication system to which a method proposed by the present specification may be applied.

[8] FIG. 4 illustrates one example of a self-contained subframe structure to

which a method proposed by the present specification may be applied.

[9] FIG. 5 illustrates a transceiver unit model in a wireless communication

system to which the present disclosure may be applied.

[10] FIG. 6 is a flow diagram illustrating one example of a CSI-related procedure.

[11] FIG. 7 illustrates one example of the timing at which a periodic CSI-RS is

received.

o [12] FIGs. 8 and 9 illustrate another example of the timing at which a period CSI

RS is received.

[13] FIG. 10 illustrates one example of a method for measuring CSI by using an

AP CSI-RS.

[14] FIG. 11 illustrates one example of another method for measuring CSI by

using an AP CSI-RS.

[15] FIG. 12 illustrates one example of an A-CSI report trigger for single CSI

proposed by the present specification.

[16] FIG. 13 illustrates one example of an A-CSI report trigger for single CSI

having a periodic CSI-RS proposed by the present specification.

[17] FIGs. 14 and 15 illustrate examples of a method for determining a time offset

of a CSI reference resource proposed by the present specification.

[18] FIG. 16 illustrates one example of an A-CSI report trigger for single CSI

having an aperiodic CSI-RS proposed by the present specification.

[19] FIG. 17 is a flow diagram illustrating one example of a method for operating a

UE which performs CSI reporting proposed by the present specification.

[20] FIG. 18 is a flow diagram illustrating one example of a method for operating

an eNB which receives a CSI report proposed by the present specification.

[21] FIG. 19 illustrates one example of a method for implementing the nCQREF

value proposed by the present specification.

[22] FIG. 20 illustrates a block diagram of a wireless communication device to

which methods proposed by the present specification may be applied.

[23] FIG. 21 illustrates a block diagram of a communication device according to

one embodiment of the present disclosure.

[24] FIG. 22 illustrates one example of an RF module of a wireless

communication device to which a method proposed by the present specification may

be applied.

[25] FIG. 23 illustrates another example of an RF module of a wireless

communication device to which a method proposed by the present specification may

be applied.

[Detailed Description]

[26] An object of the present disclosure is to provide a method for determining a

CSI reference resource related to CSI reporting.

[27] Technical objects to be achieved by the present disclosure are not limited to

those described above, and other technical objects not mentioned above may also

be clearly understood from the descriptions given below by those skilled in the art to

which the present disclosure belongs.

[28] The present document provides a method for transmitting and receiving a

CSI-RS in a wireless communication system.

[29] More specifically, a method performed by a user equipment (UE) comprises

receiving, by the UE and from a base station (BS), downlink control information (DCI) related to an aperiodic CSI report that is to be performed by the UE in a slot n; determining, by the UE, a value ncQ,_ref based on a number of symbols Z' related to a time for computing the CSI; determining, by the UE, a CSI reference resource as being a slot n - ncQ,_ref in a time domain that is to be used for the aperiodic CSI report; and transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n - ncQ,_rer

[30] Also, according to the present disclosure, the ncQ,_ref is a smallest value

greater than or equal to[Z' slot such thattheslotn- ncrref satisfies a valid . symbJ

downlink slot criteria, and wherein- Jis a floor function and Nsy'mb is a number of

symbols in one slot.

[31] Also, according to the present disclosure, the valid downlink slot criteria is

based at least on (i) the number of symbols Z' related to the time for computing the

CSI and (ii) a DCI processing time.

[32] Also, according to the present disclosure, Nsylmb is equal to 14 symbols in a

slot.

[33] Also, the method according to the present disclosure further comprises

receiving, from the BS, an aperiodic reference signal (CSI-RS) in the CSI reference

resource, slot n - ncQIre; determining the CSI based on the aperiodic CSI-RS; and

generating the aperiodic CSI report based on the CSI.

[34] Also, the method according to the present disclosure further comprises

determining the number of symbols Z' related to the time for computing the CSI

based on a CSI complexity and a subcarrier spacing.

[35] Also, according to the present disclosure, the number of symbols Z' does

not include a DCI processing time.

[36] Also, according to the present disclosure, determining the value ncQI-ref based on the number of symbols Z' related to the time for computing the CSI comprises: determining the value nc,_ref based on the number of symbols Z' related to the time for computing the CSI, and further based on a number of symbols in one slot.

[37] Also, according to the present disclosure, receiving the DCI comprises:

receiving the DCI in a slot other than the slot n in which the aperiodic CSI report is

to be performed.

[38] Also, according to the present disclosure, based on the value ncQ,_ref being

equal to zero, the aperiodic CSI report is performed in a same slot as receiving the

o DCI.

[39] Also, a user equipment (UE) configured to report channel state information

(CSI) in a wireless communication system, the UE comprising: a radio frequency (RF)

module configured to transmit and receive radio signals; at least one processor; and

at least one computer memory operably connectable to the at least one processor

and storing instructions that, when executed, cause the at least one processor to

perform operations comprising: receiving, via the RF module and from a base station

(BS),downlink control information (DCI) related to an aperiodic CSI report that is to

be performed by the UE in a slot n; determining, by the UE, a value ncQi-ref based

on a number of symbols Z' related to a time for computing the CSI; determining, by

the UE, a CSI reference resource as being a slot n - ncQi-ref in a time domain that

is to be used for the aperiodic CSI report; and transmitting, via the RF module and to

the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource

being slot n - ncQirefr

[40] The present disclosure determines a CSI reference resource as close as

possible to a CSI reporting time, thereby preventing a resource (a few symbols) from being wasted without being used and reporting the most recent CSI by computing

CSI based on the most recently received CSI-RS.

[41] The technical effects of the present disclosure are not limited to the technical

effects described above, and other technical effects not mentioned herein may be

understood to those skilled in the art to which the present disclosure belongs from

the description below.

[42] In what follows, preferred embodiments of the present disclosure will be

described in detail with reference to appended drawings. Detailed descriptions to

be disclosed below with reference to the appended drawings are intended to

describe illustrative embodiments, but are not intended to represent the sole

embodiment of the present disclosure. Detailed descriptions below include specific

details to provide complete understanding of the present disclosure. However, it

should be understood by those skilled in the art that the present disclosure may be

embodied without the specific details to be introduced.

[43] In some cases, to avoid obscuring the gist of the present disclosure, well

known structures and devices may be omitted or may be depicted in the form of a

block diagram with respect to core functions of each structure and device.

[44] A base station in this document is regarded as a terminal node of a network,

which performs communication directly with a UE. In this document, particular

operations regarded to be performed by the base station may be performed by an

upper node of the base station depending on situations. In other words, it is

apparent that in a network consisting of a plurality of network nodes including a base

station, various operations performed for communication with a UE can be

performed by the base station or by network nodes other than the base station.

The term Base Station (BS) may be replaced with a term such as fixed station, Node

B, evolved-NodeB (eNB), Base Transceiver System (BTS), Access Point (AP), or

general NB (gNB). Also, a terminal can be fixed or mobile; and the term may be

replaced with a term such as User Equipment (UE), Mobile Station (MS), User

Terminal (UT), Mobile Subscriber Station (MSS), Subscriber Station (SS), Advanced

Mobile Station (AMS), Wireless Terminal (WT), Machine-Type Communication (MTC)

device, Machine-to-Machine (M2M) device, or Device-to-Device (D2D) device.

[45] In what follows, downlink (DL) refers to communication from a base station to

a terminal, while uplink (UL) refers to communication from a terminal to a base

station. In downlink transmission, a transmitter may be part of the base station, and

a receiver may be part of the terminal. Similarly, in uplink transmission, a

transmitter may be part of the terminal, and a receiver may be part of the base

station.

[46] Specific terms used in the following descriptions are introduced to help

understanding the present disclosure, and the specific terms may be used in

different ways.

[47] The technology described below may be used for various types of wireless

access systems based on Code Division Multiple Access (CDMA), Frequency

Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal

Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division

Multiple Access (SC-FDMA), or Non-Orthogonal Multiple Access (NOMA). CDMA

may be implemented by such radio technology as Universal Terrestrial Radio Access

(UTRA) or CDMA2000. TDMA can be implemented by such radio technology as

Global System for Mobile communications (GSM), General Packet Radio Service

(GPRS), or Enhanced Data rates for GSM Evolution (EDGE). OFDMA may be

implemented by such radio technology as the IEEE 802.11 (Wi-Fi), the IEEE 802.16

(WiMAX), the IEEE 802-20, or Evolved UTRA (E-UTRA). UTRA is part of the

Universal Mobile Telecommunications System (UMTS). The 3rd Generation

Partnership Project (3GPP) Long Term Evolution (LTE) is part of the Evolved UMTS

(E-UMTS) which uses the E-UTRA, employing OFDMA for downlink and SC-FDMA

for uplink transmission. The LTE-A (Advanced) is an evolved version of the 3GPP

LTE system.

[48] The 5G NR defines enhanced Mobile Broadband (eMBB), massive Machine

Type Communication (mMTC), Ultra-Reliable and Low Latency Communications

(URLLC), and vehicle-to-everything (V2X) depending on usage scenarios.

[49] And the 5G NR standard is divided into standalone (SA) and non-standalone

(NSA) modes according to co-existence between the NR system and the LTE

system.

[50] And the 5G NR supports various subcarrier spacing and supports CP-OFDM

for downlink transmission while CP-OFDM and DFT-s-OFDM (SC-OFDM) for uplink

transmission.

[51] The embodiments of the present disclosure may be supported by standard

documents disclosed for at least one of wireless access systems such as the IEEE

802, 3GPP, and 3GPP2. In other words, those steps or portions among

embodiments of the present disclosure not described to clearly illustrate the

technical principles of the present disclosure may be backed up by the

aforementioned documents. Also, all of the terms disclosed in the present

document may be described by the aforementioned standard documents.

[52] For the purpose of clarity, descriptions are given mainly with respect to the

3GPP LTE/LTE-A,but the technical features of the present disclosure are not limited

to the specific system.

[53] Definition of terms

[54] eLTE eNB: An eLTE eNB is an evolution of an eNB that supports a

connection for an EPC and an NGC.

[55] gNB: A node for supporting NR in addition to a connection with an NGC

[56] New RAN: A radio access network that supports NR or E-UTRA or interacts

with an NGC

[57] Network slice: A network slice is a network defined by an operator so as to

provide a solution optimized for a specific market scenario that requires a specific

requirement together with an inter-terminal range.

[58] Network function: A network function is a logical node in a network infra that

has a well-defined external interface and a well-defined functional operation.

[59] NG-C: A control plane interface used for NG2 reference point between new

RAN and an NGC

[60] NG-U: A user plane interface used for NG3 reference point between new

RAN and an NGC

[61] Non-standalone NR: A deployment configuration in which a gNB requires an

LTE eNB as an anchor for a control plane connection to an EPC or requires an eLTE

eNB as an anchor for a control plane connection to an NGC

[62] Non-standalone E-UTRA: A deployment configuration an eLTE eNB requires

a gNB as an anchor for a control plane connection to an NGC.

[63] User plane gateway: A terminal point of NG-U interface

[64]

[65] Numerology: corresponds to one subcarrier spacing in the frequency domain.

Different numerology may be defined by scaling reference subcarrier spacing by an integer N.

[66] NR: NR Radio Access or New Radio

[67] General System

[68] FIG. 1 is a diagram illustrating an example of an overall structure of a new

radio (NR) system to which a method proposed by the present disclosure may be

implemented.

[69] Referring to FIG. 1, an NG-RAN is composed of gNBs that provide an NG-RA

user plane (new AS sublayer/PDCP/RLC/MAC/PHY) and a control plane (RRC)

protocol terminal for a UE (User Equipment).

[70] The gNBs are connected to each other via an Xn interface.

[71] The gNBs are also connected to an NGC via an NG interface.

[72] More specifically, the gNBs are connected to a Access and Mobility

Management Function (AMF) via an N2 interface and a User Plane Function (UPF)

via an N3 interface.

[73]

[74] NR (New Rat) Numerology and frame structure

[75] In the NR system, multiple numerologies may be supported. The

numerologies may be defined by subcarrier spacing and a CP (Cyclic Prefix)

overhead. Spacing between the plurality of subcarriers may be derived by scaling

basic subcarrier spacing into an integer N (orn'). In addition, although a very low

subcarrier spacing is assumed not to be used at a very high subcarrier frequency, a

numerology to be used may be selected independent of a frequency band.

[76] In addition, in the NR system, a variety of frame structures according to the

multiple numerologies may be supported.

[77] Hereinafter, an Orthogonal Frequency Division Multiplexing (OFDM)

numerology and a frame structure, which may be considered in the NR system, will

be described.

[78] A plurality of OFDM numerologies supported in the NR system may be

defined as in Table 1.

[79] [Table 1]

S 4f = 2"' .15 [kHz] Cyclic prefix

0 15 Normal

1 30 Normal

2 60 Normal, Extended

3 120 Normal

4 240 Normal

5 480 Normal

[80] Regarding a frame structure in the NR system, a size of various fields in the

time domain is expressed as a multiple of a time unit of T = 1/(Af. -Nf). In this

case, A4max = 480-103, and N = 4096. DL and UL transmission is configured as a

radio frame having a section of T =(AfNf/100)-T, =10ms. The radio frame is

composed of ten subframes each having a section of T =(AfNf/1000).T, =lms.

In this case, there may be a set of UL frames and a set of DL frames.

[81] FIG. 2 illustrates a relationship between a UL frame and a DL frame in a

wireless communication system to which a method proposed by the present

disclosure may be implemented.

[82] As illustrated in FIG. 2, a UL frame number I from a User Equipment (UE)

needs to be transmitted TTA =NTAT before the start of acorresponding DL frame in

the UE.

[83] Regarding the numerology 4 , slots are numbered in ascending order of

nP cf 10.., slots,P _PE= 0 . an i oreo efr. ATmt,p 1 s subframe -1 in a subframe, and in ascending order of n, 0,..,ame

in a radio frame. One slot is composed of continuous OFDM symbols of N b, and

N b is determined depending on a numerology in use and slot configuration. The

start of slots nr in a subframe is temporally aligned with the start of OFDM symbols

n Nymb in the same subframe.

o [84] Not all UEs are able to transmit and receive at the same time, and this

means that not all OFDM symbols in a DL slot or an UL slot are available to be used.

[85] Table 2 shows the number of OFDM symbols per slot for a normal CP in the

numerology 4 , and Table 3 shows the number of OFDM symbols per slot for an

extended CP in the numerology .

[86] [Table 2] Slot configuration

O 1

symb frame Nubframe symb rame st

0 14 10 1 7 20 2 1 14 20 2 7 40 4

2 14 40 4 7 80 8

3 14 80 8 - -

4 14 160 16 -

5 14 320 32 -

[87] [Table 3] Slot configuration

y 0 1

Nsimb N e ° btese Nsimb Nf, ° N,.te' symb Nfla.me ""Ifre ymb tael ubfram"e

0 12 10 1 6 20 2

1 12 20 2 6 40 4

2 12 40 4 6 80 8

3 12 80 8 - -

4 12 160 16 - -

5 12 320 32 - -

[88]

[89] NR physical resource

[90] Regarding physical resources in the NR system, an antenna port, a resource

grid, a resource element, a resource block, a carrier part, etc. may be considered.

[91] Hereinafter, the above physical resources possible to be considered in the

NR system will be described in more detail.

[92] First, regarding an antenna port, the antenna port is defined such that a

channel over which a symbol on one antenna port is transmitted can be inferred from

another channel over which a symbol on the same antenna port is transmitted.

When large-scale properties of a channel received over which a symbol on one

antenna port can be inferred from another channel over which a symbol on another

antenna port is transmitted, the two antenna ports may be in a QC/QCL (quasi co

located or quasi co-location) relationship. Herein, the large-scale properties may

include at least one of delay spread, Doppler spread, Doppler shift, average gain, and average delay.

[93] FIG. 3 illustrates an example of a resource grid supported in a wireless

communication system to which a method proposed by the present disclosure may

be implemented.

[94] Referring to FIG. 3, a resource grid is composed ofN"BN subcarriersina

frequency domain, each subframe composed of 14-2p OFDM symbols, but the

present disclosure is not limited thereto.

[95] In the NR system, a transmitted signal is described by one or more resource NRBR 1N grids, composed ofN BB subcarriers, and 2"Nb OFDM symbols Herein,

o N B 5 NRB". The above NRB indicates the maximum transmission bandwidth, and

it may change not just between numerologies, but between UL and DL.

[96] In this case, as illustrated in FIG. 3, one resource grid may be configured for

the numerology 4 and an antenna port p.

[97] Each element of the resource grid for the numerology 4 and the antenna

port p is indicated as a resource element, and may be uniquely identified by an index

pair(k,I) Herein, k= ,...,N"B B-is an index in the frequency domain, and

=0,...,2"N , b -1 indicates a location of a symbol in a subframe. To indicate a

resource element in a slot, the index pair (k,) is used. Herein, ' '''Nsm -1

[98] The resource element (k,) for the numerology 4 and the antenna port p

corresponds to a complex value a. When there is no risk of confusion or when

a specific antenna port or numerology is specified, the indexes p and 4 may be a(") a,, dropped and thereby the complex value may become *,i or *

[99] In addition, a physical resource block is defined as NRB continuous

subcarriers in the frequency domain. In the frequency domain, physical resource

blocks may be numbered from 0 to NB . At this point, a relationship between

the physical resource block number nPRB and the resource elements (k,l) may be

given as in Equation 1.

[100] [Equation 1]

k nPRB RB

[101] In addition, regarding a carrier part, a UE may be configured to

receive or transmit the carrier part using only a subset of a resource grid. At this

o point, a set of resource blocks which the UE is configured to receive or transmit are

numbered from 0 toNRB in the frequency region.

[102]

[103] Self-contained subframe structure

[104] FIG. 4 is a diagram illustrating an example of a self-contained

subframe structure in a wireless communication system to which the present

disclosure may be implemented.

[105] In order to minimize data transmission latency in a TDD system, 5G

new RAT considers a self-contained subframe structure as shown in FIG. 4.

[106] In FIG. 4, a diagonal line area (symbol index 0) represents a UL

control area, and a black area (symbol index 13) represents a UL control area. A

non0shade area may be used for DL data transmission or for UL data transmission.

This structure is characterized in that DL transmission and UL transmission are performed sequentially in one subframe and therefore transmission of DL data and reception of UL ACK/NACK may be performed in the subframe. In conclusion, it is possible to reduce time for retransmitting data upon occurrence of a data transmission error and thereby minimize a latency of final data transmission.

[107] In this self-contained subframe structure, a time gap is necessary for

a base station or a UE to switch from a transmission mode to a reception mode or to

switch from the reception mode to the transmission mode. To this end, some

OFDM symbols at a point in time of switching from DL to UL in the self-contained

subframe structure are configured as a guard period (GP).

o [108]

[109] Analog beamforming

[110] Since a wavelength is short in a Millimeter Wave (mmW) range, a plurality of

antenna elements may be installed in the same size of area. That is, a wavelength

in the frequency band 30GHz is 1cm, and thus, 64 (8x8) antenna elements may be

installed in two-dimensional arrangement with a 0.5 lambda (that is, a wavelength) in

4 X 4 (4 by 4) cm panel. Therefore, in the mmW range, the coverage may be

enhanced or a throughput may be increased by increasing a beamforming (BF) gain

with a plurality of antenna elements.

[111] In this case, in order to enable adjusting transmission power and phase for

each antenna element, if a transceiver unit (TXRU) is included, independent

beamforming for each frequency resource is possible. However, it is not cost

efficient to install TXRU at each of about 100 antenna elements. Thus, a method is

considered in which a plurality of antenna elements is mapped to one TXRU and a

direction of beam is adjusted with an analog phase shifter. Such an analog BF

method is able to make only one beam direction over the entire frequency band, and there is a disadvantage that frequency-selective BF is not allowed.

[112] A hybrid BF may be considered which is an intermediate between digital BF

and analog BF, and which has B number of TXRU less than Q number of antenna

elements. In this case, although varying depending upon a method of connecting B

number of TXRU and Q number of antenna elements, beam directions capable of

being transmitted at the same time is restricted to be less than B.

[113] Hereinafter, typical examples of a method of connecting TXRU and antenna

elements will be described with reference to drawings.

[114] FIG. 5 is an example of a transceiver unit model in a wireless communication

system to which the present disclosure may be implemented.

[115] A TXRU virtualization model represents a relationship between output signals

from TXRUs and output signals from antenna elements. Depending on a

relationship between antenna elements and TXRUs, the TXRU virtualization model

may be classified as a TXRU virtualization model option-1: sub-array partition model,

as shown in FIG. 5(a), or as a TXRU virtualization model option-2: full-connection

model.

[116] Referring to FIG. 5(a), in the sub-array partition model, the antenna elements

are divided into multiple antenna element groups, and each TXRU may be

connected to one of the multiple antenna element groups. In this case, the antenna

elements are connected to only one TXRU.

[117] Referring to FIG. 5(b), in the full-connection model, signals from multiple

TXRUs are combined and transmitted to a single antenna element (or arrangement

of antenna elements). That is, this shows a method in which a TXRU is connected

to all antenna elements. In this case, the antenna elements are connected to all the

TXRUs.

[118] In FIG. 5, q represents a transmitted signal vector of antenna elements

having M number of co-polarized in one column. W represents a wideband TXRU

virtualization weight vector, and W represents a phase vector to be multiplied by an

analog phase shifter. That is, a direction of analog beamforming is decided by W.

x represents a signal vector of M_TXRU number of TXRUs.

[119] Herein, mapping of the antenna ports and TXRUs may be performed on the

basis of 1-to-1 or 1-to-many.

[120] TXRU-to-element mapping In FIG. 5 is merely an example, and the

present disclosure is not limited thereto and may be equivalently applied even to

mapping of TXRUs and antenna elements which can be implemented in a variety of

hardware forms.

[121]

[122] Channel State Information (CSI) feedback

[123] In most cellular systems including an LTE system, a UE receives a

pilot signal (or a reference signal) for estimating a channel from a base station,

calculate channel state information (CSI), and reports the CSI to the base station.

[124] The base station transmits a data signal based on the CSI information

fed back from the UE.

[125] The CSI information fed back from the UE in the LTE system includes

channel quality information (CQI), a precoding matrix index (PMI), and a rank

indicator (RI).

[126] CQI feedback is wireless channel quality information which is

provided to the base station for a purpose (link adaptation purpose) of providing a

guidance as to which modulation & coding scheme (MCS) to be applied when the

base station transmits data.

[127] In the case where there is a high wireless quality of communication

between the base station and the UE, the UE may feed back a high CQI value and

the base station may transmit data by applying a relatively high modulation order and

a low channel coding rate. In the opposite case, the UE may feed back a low CQI

value and the base station may transmit data by applying a relatively low modulation

order and a high channel coding rate.

[128] PMI feedback is preferred precoding matrix information which is

provided to a base station in order to provide a guidance as to which MIMO

precoding scheme is to be applied when the base station has installed multiple

antennas.

[129] A UE estimates a downlink MIMO channel between the base station

and the UE from a pilot signal, and recommends, through PMI feedback, which

MIMO precoding is desired to be applied by the base station.

[130] In the LTE system, only linear MIMO precoding capable of expressing

PMI configuration in a matrix form is considered.

[131] The base station and the UE share a codebook composed of a

plurality of precoding matrixes, and each MIMO precoding matrix in the codebook

has a unique index.

[132] Accordingly, by feeding back an index corresponding to the most

preferred MIMO precoding matrix in the codebook as PMI, the UE minimizes an

amount of feedback information thereof.

[133] A PMI value is not necessarily composed of one index. For example,

in the case where there are eight transmitter antenna ports in the LTE system, a final

8tx MIMO precoding matrix may be derived only when two indexes (first PMI &

second PMI) are combined.

[134] RI feedback is information on the number of preferred transmission

layers, the information which is provided to the base station in order to provide a

guidance as to the number of the UE's preferred transmission layers when the base

station and the UE have installed multiple antennas to thereby enable multi-layer

transmission through spatial multiplexing.

[135] The RI and the PMI are very closely corelated to each other. It is

because the base station is able to know which precoding needs to be applied to

which layer depending on the number of transmission layers.

[136] Regarding configuration of PMI/RM feedback, a PMI codebook may

be configured with respect to single layer transmission and then PMI may be defined

for each layer and fed back, but this method has a disadvantage that an amount of

PMI/RI feedback information increases remarkably in accordance with an increase in

the number of transmission layers.

[137] Accordingly, in the LTE system, a PMI codebook is defined depending

on the number of transmission layers. That is, for R-layer transmission, N number

of Nt x R matrixes are defined (herein, R represents the number of layers, Nt

represents the number of transmitter antenna ports, and N represents the size of the

codebook).

[138] Accordingly, in LTE, a size of a PMI codebook is defined irrespective

of the number of transmission layers. As a result, since PMI/RI is defined in this

structure, the number of transmission layers (R) conforms to a rank value of the

precoding matrix (Nt x R matrix), and, for this reason, the term "rank indicator(RI)" is

used.

[139] Unlike PMI/RI in the LTE system, PMI/RI described in the present

disclosure is not restricted to mean an index value of a precoding matrix Nt x R and a rank value of the precoding matrix.

[140] PMI described in the present disclosure indicates information on a

preferred MINO precoder from among MIMO precoders capable of being applied by

a transmitter, and a form of the precoder is not limited to a linear precoder which is

able to be expressed in a matrix form, unlike in the LTE system. In addition, RI

described in the present disclosure means wider than RO in LTE and includes

feedback information indicating the number of preferred transmission layers.

[141] The CSI information may be obtained in all system frequency

domains or in some of the frequency domains. In particular, in a broad bandwidth

system, it may be useful to obtain CSI information on some frequency domains (e.g.,

subband) preferred by each UE and then feedback the obtained CSI information.

[142] In the LTE system, CSI feedback is performed via an UL channel, and,

in general, periodic CSI feedback is performed via a physical uplink control channel

(PUCCH) and aperiodic CSI feedback is performed via physical uplink shared

channel (PUSCH) which is a UL data channel.

[143] The aperiodic CSI feedback means temporarily transmitting a

feedback only when a base station needs CSI feedback information, and the base

station triggers the CSI feedback via a DL control channel such as a

PDCCH/ePDCCH.

[144] In the LTE system, which information a UE needs to feedback in

response to triggering of CSI feedback is defined as a PUSCH CSI reporting mode,

as shown in FIG. 8, and a PUSCH CSI reporting mode in which the UE needs to

operate is informed for the UE in advance via a higher layer message.

[145]

[146] Channel State Information (CSI)-related Procedure

[147] In the new radio (NR) system, a channel state information-reference

signal (CSI-RS) is used for time/frequency tracking, CSI computation, layer 1(L1)

reference signal received power (RSRP) computation, or mobility

[148] Throughout the present disclosure, "A and/or B" may be interpreted

as the same as "including at least one of A or B".

[149] The CSI computation is related to CSI acquisition, and L1-RSRP

computation is related to beam management (BM).

[150] The CSI indicates all types of information indicative of a quality of a

radio channel (or link) formed between a UE and an antenna port.

[151] Hereinafter, operation of a UE with respect to the CSI-related

procedure will be described.

[152] FIG. 6 is a flowchart illustrating an example of a CSI-related

procedure.

[153] To perform one of the above purposes of a CSI-RS, a terminal (e.g., a

UE) receives CSI related configuration information from a base station (e.g., a

general node B (gNB)) through a radio resource control (RRC) signaling(S610).

[154] The CSI-related configuration information may include at least one of

CSI interference management (IM) resource-related information, CSI measurement

configuration-related information, CSI resource configuration-related information,

CSI-RS resource-related information, or CSI report configuration-related information.

[155] The CSIIM resource-related information may include CSI-IM resource

information, CSI-IM resource set information, etc..

[156] The CSI-IM resource set is identified by a CSI-IM resource set ID

(identifier), and one resource set includes at least one CSI-IM resource.

[157] Each CSI-IM resource is identified by a CSI-IM resource ID.

[158] The CSI resource configuration-related information defines a group

including at least one of a non-zero power (NZP) CSI-RS resource set, a CSI-IM

resource set, or a CSI-SSB resource set.

[159] That is, the CSI resource configuration-related information includes a

CSI-RS resource set list, and the CSI-RS resource set list may include at least one

of a NZP CSI-RS resource set list, a CSI-IM resource set list, or a CSI-SSB resource

set list.

[160] The CSI resource configuration-related information may be expressed

as CSI-REsourceConfig IE.

o [161] The CSI-RS resource set is identified by a CSI-RS resource set ID,

and one resource set includes at least one CSI-RS resource.

[162] Each CSI-RS resource is identified by a CSI-RS resource ID.

[163] As shown in Table 4, parameters (e.g.: the BM-related parameter

repetition, and the tracking-related parameter trs-Info indicative of(or indicating) a

purpose of a CSI-RS may be set for each NZP CSI-RS resource set.

[164] Table 4 shows an example of NZP CSI-RS resource set IE.

[165] [Table 4] -- ASN1START

-- TAG-NZP-CSI-RS-RESOURCESET-START

NZP-CSI-RS-ResourceSet ::= SEQUENCE{

nzp-CSI-ResourceSetld NZP-CSI-RS-ResourceSetld,

nzp-CSI-RS-Resources SEQUENCE (SIZE (1..maxNrofNZP-CSI-RS-ResourcesPerSet)) OF NZP-CSI-RS-Resourceld,

repetition ENUMERATED { on, off }

aperiodicTriggeringOffset INTEGER(O..4)

trs-Info ENUMERATED {true}

-- TAG-NZP-CSI-RS-RESOURCESET-STOP

-- ASN1STOP

[166] In Table 4, the parameter repetition is a parameter indicative of

whether to repeatedly transmit the same beam, and indicates whether repetition is

set to "ON" or "OFF" for each NZP CSI-RS resource set.

[167] The term "transmission (Tx) beam" used in the present disclosure

may be interpreted as the same as a spatial domain transmission filter, and the term

"reception (Rx) beam" used in the present disclosure may be interpreted as the

same as a spatial domain reception filter.

[168] For example, when the parameter repetition in Table 4 is set to "OFF",

a UE does not assume that a NZP CSI-RS resource(s) in a resource set is

o transmitted to the same DL spatial domain transmission filter and the same Nrofports

in all symbols.

[169] In addition, the parameter repetition corresponding to a higher layer

parameter corresponds to "CSI-RS-ResourceRep" of L1 parameter.

[170] The CSI report configuration related information includes the

parameter reportConfigType indicative of a time domain behavior and the parameter

reportQuantity indicative of a CSI-related quantity to be reported.

[171] The time domain behavior may be periodic, aperiodic, or semi

persistent.

[172] In addition, the CSI report configuration-related information may be

represented as CSI-ReportConfig IE, and Table 5 shows an example of the CSI

ReportConfig IE.

[173] [Table 5] -- ASN1START

-- TAG-CSI-RESOURCECONFIG-START

CSI-ReportConfig ::= SEQUENCE{

reportConfigld CSI-ReportConfigld,

carrier ServCelllndex OPTIONAL, -- Need S

resourcesForChannelMeasurement CSI-ResourceConfigld,

csi-IM-ResourcesForlnterference CSI-ResourceConfigld OPTIONAL, -- Need R

nzp-CSI-RS-ResourcesForlnterference CSI-ResourceConfigld OPTIONAL, -- Need R

reportConfigType CHOICE

periodic SEQUENCE{

reportSlotConfig CSI-ReportPeriodicityAndOffset,

pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource

semiPersistentOnPUCCH SEQUENCE{

reportSlotConfig CSI-ReportPeriodicityAndOffset,

pucch-CSI-ResourceList SEQUENCE (SIZE (1..maxNrofBWPs)) OF PUCCH-CSI-Resource

semiPersistentOnPUSCH SEQUENCE{

reportSlotConfig ENUMERATED {s15, s10, s120, s140, s180, sI160, s1320},

reportSlotOffsetList SEQUENCE (SIZE (1.. maxNrofUL-Allocations)) OF INTEGER(O..32),

pOalpha PO-PUSCH-AlphaSetld

aperiodic SEQUENCE{

reportSlotOffsetList SEQUENCE (SIZE (1..maxNrofUL-Allocations)) OF INTEGER(..32) reportQuantity CHOICE { none NULL, cri-RI-PMI-CQI NULL, cri-RI-il NULL, cri-RI-il-CQI SEQUENCE{ pdsch-BundleSizeForCSI ENUMERATED {n2, n4} OPTIONAL cri-RI-CQI NULL, cri-RSRP NULL, ssb-Index-RSRP NULL, cri-RI-LI-PMI-CQ NULL

[174] In addition, the UE measures CSI based on configuration information

related to the CSI (S620).

[175] Measuring the CSI may include (1) receiving a CSI-RS by the UE

(S621) and (2) computing CSI based on the received CSI-RS (S622).

[176] A sequence for the CSI-RS is generated by Equation 2, and an

initialization value of a pseudo-random sequence C(i) is defined by Equation 3.

[177] [Equation 2]

1 1 r(m)= 1(1-2. c(2m))+j (1-2. c(2m+1))

[178] [Equation 3]

ci = (210(N bn"f+ + 1)(2nID + 1) + nID)mod23

[179] In Equations 2 and 3, n/i is a slot number within a radio frame, and a

pseudo-random sequence generator is initialized with Cint at the start of each OFDM symbol where nf is the slot number within a radio frame.

[180] In addition, I indicates an OFDM symbol number in a slot, and "ID

indicates higher-layer parameter scramblinglD.

[181] In addition, regarding the CSI-RS, resource element (RE) mapping of

CSI-RS resources of the CSI-RS is performed in time and frequency domains by

higher layer parameter CSI-RS-ResourceMapping.

[182] Table 6 shows an example of CSI-RS-ResourceMapping IE.

[183] [Table 6] -- ASNISTART

-- TAG-CSI-RS-RESOURCEMAPPING-START

CSI-RS-ResourceMapping :: SEQUENCE {

frequencyDomainAllocation CHOICE {

rowl BIT STRING (SIZE (4)),

row2 BIT STRING (SIZE (12)),

row4 BIT STRING (SIZE (3)),

other BIT STRING (SIZE (6))

nrofPorts ENUMERATED {p1,p2,p4,p8,p12,p16,p24,p32},

firstOFDMSymbolInTimeDomain INTEGER (0..13),

firstOFDMSymbolInTimeDomain2 INTEGER (2..12)

cdm-Type ENUMERATED {noCDM, fd-CDM2, cdm4-FD2-TD2, cdm8-FD2 TD4},

density CHOICE {

dot5 ENUMERATED {evenPRBs, oddPRBs},

one NULL,

three NULL,

spare NULL

freqBand CSI-FrequencyOccupation,

[184] In Table 6, a density (D) indicates a density of CSI-RS resources

measured in a RE/port/physical resource block (PRB), and nrofPorts indicates the

number of antenna ports.

[185] In addition, the UE reports the measured CSI to the base station

(S630).

[186] Herein, when a quantity of CSI-ReportConfig in Table 6 is set to

"none(or No report)", the UE may skip the reporting.

[187] However, even when the quantity is set to "none(or No report)", the

UE may report the measured CSI to the base station.

o [188] The case where the quantity is set to "none" is t when an aperiodic

TRS is triggered or when repetition is set.

[189] Herein, it may be defined such that reporting by the UE is omitted

only when repetition is set to "ON".

[190] To put it briefly, when repetition is set to "ON" and "OFF", a CSI report

may indicate any one of "No report", "SSB Resource Indicator (SSBRI) and L1

RSRP", and "CSI-RS Resource Indicator (CRI) and L1-RSRP".

[191] Alternatively, it may be defined to transmit a CSI report indicative of

"SSBRI and L1-RSRP" or "CRI and L1-RSRP" when repetition is set to "OFF", it may

be defined such that, and to transmit a CSI report indicative of "No report", "SSBRI

and L1-RSRP", or "CRI and L1-RSRP" when repetition is "ON".

[192]

[193] CSI measurement and reporting procedure

[194] The NR system supports more flexible and dynamic CSI measurement and reporting.

[195] The CSI measurement may include receiving a CSI-RS, and

acquiring CSI by computing the received CSI-RS.

[196] As time domain behaviors of CSI measurement and reporting,

aperiodic/semi-persistent/periodic channel measurement (CM) and interference

measurement (IM) are supported.

[197] To configure CSI-IM, four port NZP CSI-RS RE patterns are used.

[198] CSI-IM-based IMR of NR has a design similar to CSI-IM of LTE and is

configured independent of ZP CSI-RS resources for PDSCH rate matching.

[199] In addition, each port in the NZP CSI-RS-based IMR emulates an

interference layer having (a desirable channel and) a pre-coded NZP CSI-RS.

[200] This is about intra-cell interference measurement of a multi-user case,

and it primarily targets MU interference.

[201] At each port of the configured NZP CSI-RS-based IMR, the base

station transmits the pre-coded NZP CSI-RS to the UE.

[202] The UE assumes a channel/interference layer for each port in a

resource set, and measures interference.

[203] If there is no PMI or RI feedback for a channel, a plurality of

resources are configured in a set and the base station or network indicates, through

DCI, a subset of NZP CSI-RS resources for channel/interference measurement.

[204] Resource setting and resource setting configuration will be described

in more detail.

[205] Resource setting

[206] Each CSI resource setting "CSI-ResourceConfig" includes

configuration of S>1 CSI resource set (which is given by higher layer parameter "csi

RS-ResourceSetList").

[207] Herein, a CSI resource setting corresponds to CSI-RS

resourcesetlist.

[208] Herein, S represents the number of configured CSI-RS resource sets.

[209] Herein, configuration of S>1 CSI resource set includes each CSI

resource set including CSI-RS resources (composed of NZP CSI-RS or CSI-IM), and

a SS/PBCH block (SSB) resource used for L1-RSRP computation.

[210] Each CSI resource setting is positioned at a DL bandwidth part (BWP)

identified by higher layer parameter bwp-id.

o [211] In addition, all CSI resource settings linked to a CSI reporting setting have

the same DL BWP.

[212] In a CSI resource setting included in CSI-ResourceConfig IE, a time

domain behavior of a CSI-RS resource may be indicated by higher layer parameter

resourceType and may be configured to be aperiodic, periodic, or semi-persistent.

[213] The number S of CSI-RS resource sets configured for periodic and

semi-persistent CSI resource settings is restricted to "1".

[214] A periodicity and a slot offset configured for periodic and semi

persistent CSI resource settings are given from a numerology of related DL BWP,

just like being given by bwp-id.

[215] When the UE is configured with a plurality of CSI-ResourceConfig

including the same NZP CSI-RS resource ID, the same time domain behavior is

configured for the CSI-ResourceConfig.

[216] When the UE is configured with a plurality of CSI-ResourceConfig

having the same CSI-IM resource ID, the same time domain behavior is configured

for the CSI-ResourceConfig.

[217] Then, one or more CSI resource settings for channel measurement

(CM) and interference measurement (IM) are configured through higher layer

signaling.

[218] - A CSI-IM resource for interference measurement.

[219] - An NZP CSI-RS resource for interference measurement.

[220] - An NZP CSI-RS resource for channel measurement.

[221] That is, a channel measurement resource (CMR) may be an NZP

CSI-RS for CSI acquisition, and an interference measurement resource (IMR) may

be an NZP CSI-RS for CSI-IM and for IM.

[222] Herein, CSI-IM (or a ZP CSI-RS for IM) is primarily used for inter-cell

interference measurement.

[223] In addition, an NZP CSI-RS for IM is primarily used for intra-cell

interference measurement from multi-user.

[224] The UE may assume that a CSI-RS resource(s) and a CSI-IM/NZP

CSI-RS resource(s) for interference measurement configured for one CSI reporting

is "QCL-TypeD" for each resource.

[225] Resource setting configuration

[226] As described above, a resource setting may represent a resource set

list.

[227] Regarding aperiodic CSI, each trigger state configured using higher

layer parameter "CSI-AperiodicTriggerState" is that each CSI-ReportConfig is

associated with one or multiple CSI-ReportConfig linked to a periodic, semi

persistent, or aperiodic resource setting.

[228] One reporting setting may be connected to three resource settings at

maximum.

[229] - When one resource setting is configured, a resource setting (given

by higher layer parameter resourcesForChannelMeasurement) is about channel

measurement for L1-RSRP computation.

[230] - When two resource settings are configured, the first resource

setting (given by higher layer parameter resourcesForChannelMeasurement) is for

channel measurement and the second resource setting (given by csi-IM

ResourcesForInterference or nzp-CSI-RS -ResourcesForinterference) is for CSI-IM

or for interference measurement performed on an NZP CSI-RS.

[231] - When three resource settings are configured, the first resource

setting (given by resourcesForChannelMeasurement) is for channel measurement,

the second resource setting (given by csi-IM-ResourcesForlnterference) is for CSI

IM based interference measurement, and the third resource setting (given by nzp

CSI-RS-ResourcesForlnterference) is for NZP CSI-RS based interference

measurement.

[232] Regarding semi-persistent or periodic CSI, each CSI-ReportConfig is

linked to a periodic or semi-persistent resource setting.

[233] - When one resource setting (given by

resourcesForChannelMeasurement) is configured, the resource setting is about

channel measurement for L1-RSRP computation.

[234] - When two resource settings are configured, the first resource setting

(given by resourcesForChannelMeasurement) is for channel measurement, and the

second resource setting (given by tge higher layer parameter "csi-IM

ResourcesFornterference") is used for interference measurement performed on

CSI-IM.

[235]

[236] CSI computation regarding CSI measurement will be described in

more detail.

[237] If interference measurement is performed on CSI-IM, each CSI-RS

resource for channel measurement is associated with a CSI-RS resource in a

corresponding resource set by an order of CSI-RS resources and CSI-IM resources.

[238] The number of CSI-RS resources for channel measurement is the

same as the number of CSI-IM resources.

[239] In addition, when interference measurement is performed on an NZP

CSI-RS, the UE is not expected to be configured with one or more NZP CSI-RS

resources in an associated resource set within a resource setting for channel

measurement.

[240] A UE configured with higher layer parameter nzp-CSI-RS

ResourcesForInterference is not expected to be configured with 18 or more NZP

CSI-RS ports in a NZP CSI-RS resource set.

[241] For CSI measurement, the UE assumes the following.

[242] - Each NZP CSI-RS port configured for interference measurement

corresponds to an interference transmission layer.

[243] - Every interference transmission layer of NZP CSI-RS ports for

interference measurement considers an energy per resource element (EPRE) ratio.

[244] - a different interference signal on a RE(s) of an NZP CSI-RS

resource for channel measurement, an NZP CSI-RS resource for interference

measurement, or a CSI-IM resource for interference measurement.

[245]

[246] A CSI reporting procedure will be described in more detail.

[247] For CSI reporting, time and frequency resources available for an UE are controlled by a base station.

[248] CSI may include at least one of channel quality indicator (CQI), a

precoding matrix indicator (PMI), a CSI-RS resource indicator (CRI), am SS/PBCH

block resource indicator (SSBRI), a layer indicator (LI), a rank indicator (RI), or L1

RSRP.

[249] Regarding the CQ, the PMI, the CRI, the SSBRI, the LI, the RI, and

the L1-RSRP, the UE may be configured with N1 CSI-ReportConfig reporting

setting, M 1 CSI-ResourceConfig resource setting, and a list of one or two trigger

states (provided by aperiodicTriggerStateList and semiPersistentOnPUSCH

o TriggerStateList) by a higher layer.

[250] In the aperiodicTriggerStateList, each trigger state includes a channel

and a list of associated CSI-ReportConfigs selectively indicative of Resource set IDs

for interference.

[251] In the semiPersistentOnPUSCH-TriggerStateList, each trigger state

includes one associated CSI-ReportConfig.

[252] In addition, a time domain behavior of CSI reporting supports periodic,

semi-persistent, and aperiodic CSI reporting.

[253] Hereinafter, periodic, semi-persistent, and aperiodic CSI reporting will

be described.

[254] The periodic CSI presorting is performed on a short PUCCH and a

long PUCCH.

[255] A periodicity and a slot offset of the periodic CSI reporting may be

configured by RRC and refer to CSI-ReportConfig IE.

[256] Then, SP CSI reporting is performed on a short PUCCH, a long

PUCCH, or a PUSCH.

[257] In the case of SP CSI on a short/long PUCCH, a periodicity and a slot

offset are configured by RRC, and CSI reporting to an additional MAC CE is

activated/deactivated

[258] In the case of SP CSI on a PUSCH, a periodicity of SP CSI reporting

is configured by RRC, but a slot offset thereof is not configured by RRC and SP CSI

reporting is activated/deactivated by DCI (format 0_1).

[259] The first CSI reporting timing follows a PUSCH time domain allocation

value indicated by DCI, and subsequent CSI reporting timing follows a periodicity

o which is configured by RRC.

[260] For SP CSI reporting on a PUSCH, a separated RNTI (SP-CSI C

RNTI) is used.

[261] DCI format 0_1 may include a CSI request field and

activate/deactivate a specific configured SP-CSI trigger state.

[262] In addition, SP CSI reporting is activated/deactivated identically or

similarly to a mechanism having data transmission on a SPS PUSCH.

[263] Next, aperiodic CSI reporting is performed on a PUSCH and triggered

by DCI.

[264] In the case of AP CSI having an AP CSI-RS, an AP CSI-RS timing is

configured by RRC.

[265] Herein, a timing of AP CSI reporting is dynamically controlled by DCI.

[266] A reporting method (e.g., transmitting in order of RI, WB, PMI/CQI,

and SB PMI/CQI) by which CSI is divided and reported in a plurality of reporting

instances, the method which is applied for PUCCH-based CSI reporting in LTE, is

not applied in NR.

[267] Instead, NR restricts configuring specific CSI reporting on a short/long

PUCCH, and a CSI omission rule is defined.

[268] Regarding an AP CSI reporting timing, PUSCH symbol/slot location is

dynamically indicated by DCI. In addition, candidate slot offsets are configured by

RRC.

[269] Regarding CSI reporting, a slot offset(Y) is configured for each

reporting setting.

[270] Regarding UL-SCH, a slot offset K2 is configured separately.

[271] Two CSI latency classes (low latency class and high latency class)

are defined in terms of CSI computation complexity.

[272] The low latency CSI is WB CSI that includes up to 4-ports Type-I

codebook or up to 4-ports non-PMI feedback CSI.

[273] The high latency CSI is a CSI other than the low latency CSI.

[274] Regarding a normal UE, (Z, Z') is defined in a unit of OFDM symbols.

[275] Z represents the minimum CSI processing time after receiving CSI

triggering DCI and before performing CSI reporting.

[276] Z' represents the minimum CSI processing time after receiving CSI

RS about a channel/interference and before performing CSI reporting

[277] Additionally, the UE reports the number of CSI which can be

calculated at the same time.

[278]

[279] A-CSI or AP CSI used in the present specification indicates aperiodic

CSI which is the CSI reported aperiodically by the UE.

[280] Also, CSI report or CSI reporting used in the present specification

may be regarded to have the same meaning.

[281] To inform of UE capability for A-CSI computation or calculation time,

the UE reports a set of supported Z values and CSI configuration which may be

supported for each Z value to the eNB.

[282] Here, Z is defined by the minimum required number of symbols for

CSI computation for a given CSI configuration.

[283] More specifically, Z refers to the minimum amount of time required for

calculation related to AP CSI processing, such as decoding time, channel

measurement, CSI calculation, and TX preparation.

[284] A CSI configuration includes information indicating wideband (WB)

only CSI or sub-band (SB) and WB CSI; information about the maximum number of

CSI-RS ports; and information about type 1 codebook or type 2 codebook.

[285] When the UE supports a plurality of numerology, the information

about CSI may be reported for each numerology.

[286] When an A-CSI report is triggered at slot n on the PUSCH, the UE

drops the A-CSI report for the following cases:

[287] - A case where the time gap between the last symbol of the PDCCH

and the start symbol of the PUSCH in the slot n is smaller than a reported value of Z

with respect to a given CSI configuration and

[288] - A case where an AP CSI-RS resource is transmitted from the slot n,

and the time gap between the last symbol of a CSI-RS resource and the start symbol

of the PUSCH is smaller than a reported value of Z with respect to a given CSI

configuration.

[289] And those symbols between the Z symbols before the start symbol of

the PUSCH and the start symbol of the PUSCH are not valid as (CSI) reference

resources.

[290] In what follows, an A-CSI report trigger and a CSI report related

thereto will be described.

[291] When the eNB triggers an A-CSI report through downlink control

information (DCI) transmission in the slot n, the UE operates as follows.

[292] A-CSI is transmitted by the UE through the PUSCH allocated as a

resource by the DCI.

[293] The transmission timing of the PUSCH is indicated by a specific field

(which is defined as a Y value) of the DCI.

o [294] More specifically, the PUSCH is transmitted from the (n+Y)-th slot

(slot n+Y) with reference to the slot n which corresponds to the trigger time of the A

CSI report.

[295] For example, when a DCI field for the Y value is defined by 2 bits, the

Y value for 00, 01, 10, and 11 is defined respectively by RRC signaling and more

specifically, defined within a report setting defined through RRC signaling.

[296] The report setting may also be expressed by reporting setting or CSI

ReportConfig.

[297] An A-CSI report trigger may trigger one or more specific report

settings, and the value of 00, 01, 10, and 11 of the DCI field is defined according to

the Y value defined within the triggered report setting.

[298] As described above, when the time gap or timing gap between the

last symbol of the PDCCH and the start symbol of the PUSCH is smaller than the Z

value corresponding to the CSI configuration of triggered A-CSI, the UE transmits the

triggered A-CSI to the eNB without dropping or updating the A-CSI.

[299] Since the amount of time allocated for actual calculation is smaller

than the minimum amount of time Z required for calculation of the A-CSI, the UE is

unable to calculate the A-CSI.

[300] As a result, the UE does not drop or update triggered CSI.

[301] When a Non-Zero Power (NZP) CSI-RS or Zero Power (ZP) CSI-RS

used for channel estimation or interference estimation of triggered A-CSI is an

aperiodic CSI-RS, the UE estimates a channel or interference through one shot

measurement from the corresponding RS.

[302] In other words, it indicates that the UE estimates a channel or

interference by using the corresponding RS (NZP CSI-RS or ZP CSI-RS) only.

[303] At this time, if the time gap between the very last symbol of a CSI-RS

resource and the start symbol of the PUSCH is smaller than the Z value

corresponding to the CSI configuration of triggered A-CSI, in the same way as the

UE's operation described above, the UE transmits the corresponding A-CSI to the

eNB without dropping or updating the corresponding A-CSI.

[304] And when the UE calculates CSI, the UE does so by assuming

reception of data for a specific frequency and/or time resource area, which is called a

CSI reference resource.

[305] The CSI reference resource may be simply referred to as a reference

resource.

[306] Since the UE starts CSI calculation from the CSI reference resource

time, the UE may calculate CSI only when the amount of time as long as Z symbols

from the CSI reference resource time is secured.

[307] Therefore, the reference resource time has to be defined at least before z symbols (or z+1 symbols) with respect to the CSI report time.

[308] To this end, when validity of a reference resource is checked,

symbols or slots before at least z symbols (or z+1 symbols) are determined to be

valid with respect to the CSI report time, but invalid, otherwise.

[309] Here, the (CSI) reference resource is defined in units of slots.

[310] Also, the slot whose number is less than or equal to n - nCQIREF

(namely slot n - nCQIREF) is determined as the (CSI) reference resources with

reference to the slot for CSI reporting (for example, slot n).

[311] The statement above, which says that 'symbols or slots before at least z

o symbols (or z+1 symbols) are determined to be valid with respect to the CSI report

time, but invalid, otherwise', may indicate that nCQREF is configured by Eq. 4 below.

[312] [Eq. 4]

nCQIREF floor The number of OFDM symbols comprising one slot) +1

[313] In Eq. 4, floor discards digits after the decimal point and is denoted by

a symbol [J.

[314] The UE sets the most recent slot which satisfies the validity condition

for a reference resource among slots whose number is less than or equal to n

nCQiREF as a reference resource.

[315] Similarly, the UE may simply set the slot n - nCQiREF as the reference

resource.

[316] And the time offset of the CSI reference resource may be determined

on the basis of the proposal 3 to be described later, and detailed descriptions about

how the time offset of the CSI reference resource is determined will be given by the

proposal 3.

[317] The A-CSI report trigger field included in the DCI may be interpreted

as follows.

[318] When an eNB instructs a UE to perform an A-CSI trigger for a

plurality of report settings simultaneously, and a definition of the Y value is different

for each report setting, a problem occurs as described below, and a UE operation to

solve the problem through various methods will be described.

[319] For example, suppose a report setting 1 is defined as Y = {0, 1, 2, 3},

and a report setting 2 is defined as Y = {1, 2, 3, 4}.

o [320] In this case, an ambiguity occurs in which value the (2 bits) DCI field

indicating the Y value has to be interpreted.

[321] Therefore, to remove the ambiguity, it is proposed that the UE

operates according to the following methods.

[322] (Method 1)

[323] The UE newly generates Y' as an intersection between two different

Ys and interprets the DCI field according to the Y'value.

[324] In other words, in the example above, the intersection of two different

Ys is {1, 2, 3}, and the UE interprets 00, 01, 10, and 11 of the DCI field as 1, 2, 3,

and 3, respectively.

[325] If the intersection between two different Ys is {1}, the UE interprets 00,

01, 10, and 11 as 1, 1, 1, and 1, respectively.

[326] If the intersection between two different Ys is {1, 2}, the UE interprets

00,01,10,and 11as1,2,2, and 2.

[327] In the example above, when the number of elements belonging to the

intersection between two different Ys is smaller than the states (for example, 00, 01,

10, and 11) of the DCI field, the remaining states are defined by repeating the last

intersection value.

[328] However, different from the definition above, the remaining states

may be defined as reserved.

[329] (Method 2)

[330] The UE interprets the DCI field according to the Y value defined in

one of a plurality of report settings.

[331] For example, among a plurality of report settings, the UE interprets

o the DCI field by using the Y value for a report setting having a low report setting

index.

[332] Similarly, among a plurality of report setting, the UE interprets the DCI

field by using the Y value for a report setting having a low index for a component

carrier (CC).

[333] The UE puts priorities between the report setting index and the CC

index and determines a Y value for a report setting by using the CC index.

[334] If the CC index is the same, the UE may then determine the Y value

according to the report setting index.

[335] Or as described above, the priority may be reversed (a high priority is

set for the report setting index).

[336] (Method 3)

[337] The UE may expect that a plurality of report settings always have the

same Y value.

[338] In other words, the eNB configures the report settings 1 and 2 to have the same Y value through RRC signaling.

[339] For example, the eNB may configure the report setting 1 by using Y=

{1, 2, 3, 4} and the report setting 2 by using Y = {1, 2, 3, 4}.

[340] (Method 4)

[341] The UE determines the time offset of aperiodic CSI reporting by using

the larger value of two different Y values.

[342] For example, the report setting 1 may be defined by Y1= {0, 1, 2, 3},

and the report setting 2 may be defined by Y2 = {1, 2, 3, 4}.

[343] When the DCI field for Y (for example, 2 bits) is '00', Y1= 0, and Y2=

1; and therefore, the Y value is determined by'1'which is the larger of the two values.

[344] When the DCI field for Y (for example, 2 bits) is '01', Y1 = 1, and Y2 =

2; and therefore, the Y value is determined by'2'which is the larger of the two values.

[345] The Y value may be defined in the same way as above when the DCI

field value is '10' and '11', and the Y value for the DCI field value of '10' and '11' is

determined as '3'and '4', respectively.

[346] If three Y values are defined, the largest one among the three values

may be determined as a time offset by applying the same method as described

above.

[347] As described above, the eNB may instruct the UE to perform an AP

CSI reporting trigger through one DCI and determine the time offset of aperiodic CSI

reporting according to the methods described above (Methods 1 to 4) by using the Y

values defined for the respective N triggered AP CSI reporting settings.

[348] In addition, the eNB may indicate the data transmission time through

the PUSCH while performing an AP CSI reporting trigger through the same DCI

simultaneously.

[349] At this time, the data transmission time through the PUSCH is defined

as a 'K2' value, and a plurality of candidate sets are set to the UE through upper

layer signaling in advance.

[350] One of the candidate sets is determined (or selected) as a final K2

value through the DCI field (which is also called a 'timing offset field').

[351] Also, the DCI field for selecting the K2 value and the DCI field for

o selecting the Y value are not defined by separate fields but are defined by the same

DCI field.

[352] When an AP CSI reporting trigger occurs, the UE uses the

corresponding DCI field to select the Y value, and when scheduling of PUSCH data

is occurred, the corresponding DCI field is used to select the K2 value.

[353] When PUSCH data scheduling occurs while an AP CSI reporting

trigger is performed simultaneously through the DCI, an ambiguity arises about

whether to define each value of the timing offset field as a candidate of the Y value

or a candidate for the K2 value.

[354] To solve the ambiguity, it is possible to directly extend and apply the

aforementioned methods (Methods 1 to 4).

[355] In other words, the proposed methods (Methods 1 to 4) above are

related to how to define the value of the timing offset field when a plurality of Y

candidate sets are given, and Methods 1 to 4 may also be applied to the K2

candidate set by treating the K2 candidate set as one Y candidate set.

[356] For example, Method 4 may be extended and applied as described below.

[357] The UE defines the timing offset field by using the larger of different Y

and K2 values.

[358] For example, suppose a report setting 1 is defined as Y1 = {0, 1, 2, 3},

and a report setting 2 is defined as K2 = {3, 4, 5, 6}.

[359] If the DCI field of the timing offset is '00', Y1 = 0, Y2 = 1, and K2 = 3;

and therefore, the timing offset field is determined by the largest value '3'.

[360] If the DCI field is '01', Y1 = 1, Y2 = 2, and K2 = 4; and therefore, the

timing offset field is determined by the largest value '4'.

[361] The DCI field values for'10' and '11' may be determined in the same

manner, and in this case, the DCI field values for '10' and '11' are determined as '5'

and '6', respectively.

[362] The UE may multiplex PUSCH data and CSI in the slot (n + timing

offset) with respect to the slot n which has received DCI according to an indicated

DCI value and report (or transmit) the multiplexed data and CSI to the eNB

simultaneously.

[363] Now, other methods for interpreting the A-CSI report trigger-related

DCI field in addition to the aforementioned methods (Methods 1 to 4) will be

described.

[364] (Method 5)

[365] In another method, the UE constructs a union set by combining

candidate sets of different Ys and K2 candidate sets and defines the value of an n bit

timing offset DCI field as the values ranging from the largest element to the 2n-th

largest element of the union set.

[366] The UE multiplexes PUSCH data and CSI in the slot (n + timing offset)

with respect to the slot n which has received DCI according to an indicated DCI

value and reports (or transmits) the multiplexed data and CSI to the eNB

simultaneously.

[367] (Method 6)

[368] In yet another method, after constructing one set from candidate sets

of Ys through the Methods 1 to 4, a union set is constructed by combining one of the

Y candidate sets and a candidate set of K2.

o [369] And the DCI field value of an n bit timing offset is defined by the

values ranging from the largest element to the 2n-th largest element of the union set.

[370] (Method 7)

[371] Method 7 constructs one set from candidate sets of Ys through the

Methods 1 to 4 and defines the i-th value of the DCI field of the timing offset by using

a sum of the i-th element of one of the Y candidate sets and the i-th element of the

K2 candidate sets.

[372] For example, when the Y candidate set is {1,2,3,4}, and the K2

candidate set is {5, 6, 7, 8}, the respective values of the 2-bit timing offset DCI field

for 00, 01, 10, and 11 may be defined by 1+5 (6), 2+6 (8), 3+7 (10), and 4+8 (12).

[373] (Method 8)

[374] Method 8 constructs one set from candidate sets of Ys through the

Methods 1 to 4 and defines the i-th value of the timing offset DCI field as a sum of

the i-th element of the candidate set of Ys while ignoring the candidate set of K2.

[375] Next, a relaxation method forAP CSI calculation will be described.

[376] The UE reports a Z value as defined below to the eNB by using one

of capabilities of the UE forAP CSI calculation.

[377] By assuming CSI only PUSCH (no HARQ ACK/NACK) for a given

numerology and CSI complexity, Z is defined as the minimum required number of

symbols for PDCCH detection/decoding time for receiving DCI triggering a CSI

report, channel estimation time, and CSI calculation time.

[378] For low complexity CSI, one Z value for a given numerology is

o defined as shown in Table 7 below.

[379] And for high complexity CSI, one Z value for a given numerology is

defined as shown in Table 7 below.

[380] [Table 7]

Units 15 kHz 30 kHz 60 kHz 120 kHz CSI complexity SCS SCS SCS SCS

Low complexity Symbols Z1,1 Z1,2 Z1,3 Z1,4 CSI1

High complexity Symbols Z2,1 Z2,2 Z2,3 Z2,4

CSI21 High complexity Symbols ZN+1,1 ZN+1,2 ZN+1,3 ZN+1,4

[381] As described above, Z is defined as a sum of the amount of time

required for DCI decoding (which means decoding time of DCI holding AP CSI

trigger information), the amount of time required for channel estimation, and the

amount of time required for CSI calculation.

[382] According to the complexity of CSI triggered with respect to the Z value, the eNB indicates a Y value (in other words, according to whether it is low complexity CSI or high complexity CSI).

[383] If it is assumed that DCI holding an AP CSI trigger (namely AP CSI

triggering DCI) is transmitted to slot n, the UE reports the corresponding CSI to the

eNB at slot (n + timing offset Y).

[384] If the time allocated to the UE for CSI calculation is insufficient for the

UE's capability for AP CSI calculation, the UE, instead of updating (or calculating)

CSI, transmits the most recently reported CSI or arbitrary CSI (or predefined, specific

CSI, for example, CQI = 0, PMI = 0, and RI = 1) to the eNB.

[385] FIG. 7 illustrates the aforementioned situation. In other words, FIG.

7 illustrates timing at which a periodic CSI-RS is received.

[386] More specifically, FIG. 7 illustrates a situation in which the most

recent periodic (P) CSI-RS which has been received at or before reference resource

time exists within a T time period.

[387] In FIG. 7, the UE measures CSI through a periodic CSI-RS (P CSI

RS), and it may be noticed that the P CSI-RS and the CSI reference resource exist

within the time T.

[388] In this case, within the time T, the UE performs all of DCI decoding,

channel estimation, and CSI calculation.

[389] Therefore, the UE compares T and Z and if T < Z, does not calculate

(or update) CSI but transmits the most recently reported CSI or arbitrary CSI.

[390] If T >= Z, the UE calculates CSI on the basis of the periodic CSI-RS

and reports the calculated CSI to the eNB.

[391] FIGs. 8 and 9 illustrate another example of the timing at which a

period CSI-RS is received.

[392] In other words, FIGs. 8 and 9 illustrate a situation in which the most

recent P CSI-RS received at or before the reference resource time exists before the

T period.

[393] Or, FIGs. 8 and 9 illustrate a situation in which a P CSI-RS does not

exist within the T period, but the P CSI-RS exists before the T period.

[394] In other words, referring to FIGs. 8 and 9, the UE has already

performed channel measurement from a (periodic) CSI-RS before a CSI report

trigger is occurred.

[395] Therefore, in this case, the UE performs DCI decoding and CSI

calculation within the T period.

[396] The UE compares T and Z-(channel estimation time) and if T < Z

(channel estimation time), does not calculate (or update) CSI but transmits the most

recently reported CSI or arbitrary CSI to the eNB.

[397] Here, the UE may report the channel estimation time to the eNB by

using separate capability.

[398] If T >= Z-(channel estimation time), the UE calculates CSI and reports

the calculated CSI to the eNB.

[399] Here, Z-(channel estimation time) may be defined by a third variable

Z', and the UE may report Z and Z'to the eNB, respectively.

[400] FIG. 10 illustrates one example of a method for measuring CSI by

using an AP CSI-RS.

[401] First, an AP CSI-RS is defined to exist always within the time period T.

[402] In this case, within the time T, the UE performs all of DCI decoding,

channel estimation, and CSI calculation.

[403] Therefore, the UE compares T and Z and if T < Z, does not calculate

(or update) CSI but transmits the most recently reported CSI or arbitrary CSI.

[404] If T >= Z, the UE calculates CSI and reports the calculated CSI to the

eNB.

[405] FIG. 11 illustrates one example of another method for measuring CSI

by using an AP CSI-RS.

[406] More specifically, FIG. 11 illustrates a situation in which an AP CSI

RS is transmitted long after the UE finishes decoding of DCI.

[407] In this case, the UE has to perform all of DCI decoding, channel

estimation, and CSI calculation within the time period T.

[408] However, since an AP CSI-RS is transmitted long after DCI decoding

is finished, the UE is unable to perform channel measurement and CSI calculation

during the time period T until the DCI decoding is finished and the AP CSI-RS is

transmitted.

[409] Therefore, the UE compares T and Z and if T < Z, does not calculate

(or update) CSI but may transmit the most recently reported CSI or arbitrary CSI to

the eNB; however, if T >= Z, the UE is unable to calculate CSI and thus unable to

report CSI to the eNB.

[410] Therefore, to make the method as shown in FIG. 11 effective, the

eNB has to transmit an AP CSI-RS within the DCI decoding time after the last OFDM

symbol of triggering DCI.

[411] Or the eNB has to transmit an AP CSI-RS before Z-(decoding time) at the

first OFDM symbol from which AP CSI is reported.

[412] The UE may report the decoding time to the eNB through separate capability.

[413] Here, Z-(decoding time) may be defined as a third variable Z', and the

UE may report Z and Z'to the eNB, respectively.

[414] In other words, T' between the time at which the AP CSI-RS used for

channel measurement or interference measurement is last received and the start

time at which CSI is reported is smaller than Z', the UE determines that time for

calculating CSI is not sufficient and does not calculate CSI.

[415] Therefore, the UE does not report valid CSI but reports a predefined

dummy CSI value (for example, RI = 1, PMI = 1, and CQI = 1) to the eNB.

[416] Or if T' between the last OFDM symbol on which the AP CSI-RS is

transmitted and the first OFDM symbol on which the AP-CSI is reported is smaller

than Z-(decoding time), the UE does not calculate (or update) CSI but transmits the

most recently reported CSI or arbitrary CSI to the eNB.

[417] And if T' >= Z-(decoding time), and T < Z, the UE does not calculate

(or update) CSI but transmits the most recently reported CSI or arbitrary CSI.

[418] If T' >= Z-(decoding time) and T >= Z, the UE calculates CSI and

reports the calculated CSI to the eNB.

[419] The UE may report the decoding time to the eNB through separate

capability.

[420] Differently from the proposals to be described later, if Z' is introduced,

the Z in the proposals 2 and 3 may be replaced with the Z'.

[421] As described above, the Z indicates the minimum required time for all

of the calculations related to AP CSI processing such as DCI decoding time, channel

measurement, CSI calculation, and TX preparation.

[422] And the Z' indicates the minimum required time for channel measurement, CSI calculation, and TX preparation.

[423] Therefore, it may be preferable to set the time provided for the UE,

spanning from the last reception time of the CSI-RS used for channel measurement

or interference measurement to the start time at which the CSI is transmitted, with

reference to the Z'which does not include decoding time.

[424] The proposals 2 and 3 below may be limited (or restricted) to the

case where CSI is reported within a short time period after the A CSI report triggering.

[425] For example, the proposals 2 and 3 to be described later may be

applied only to the case of a small Y value such as Y = 0 (or Y = 1).

[426] If Y = 0, it may be related to the operation for self-contained CSI

feedback which is operated in one slot, including CSI report triggering, channel

measurement, and up to CSI reporting.

[427] For the self-contained structure, the descriptions given above may be

referenced.

[428] To this purpose, a reference resource is defined to be as close as

possible from slot n, and the UE is made to measure a channel by using a CSI-RS

within a time period between CSI report triggering and CSI reporting.

[429] Or even if Y is a non-zero, small value (for example, Y = 1), since the

eNB is intended to trigger CSI reporting and to receive a fresh (or new) CSI report

within a short time period, a reference resource may be defined to be as close as

possible from slot n, and the eNB may be made to perform channel measurement by

using a fresh CSI-RS close to the CSI reporting time.

[430] On the other hand, if Y is a large value, since it already takes a long

time from a triggering time to the report time, the time at which a CSI-RS measures a channel does not cause a critical problem compared to the case where Y is small.

[431] Therefore, in this case, the proposal 3 to be described later is not

applied but the time offset of the reference resource is configured by one of the

following options.

[432] First, the option 1 is described.

[433] When a P/SP/AP CSI-RS is used to calculate CSI for A-CSI reporting,

the time offset of a CSI reference resource is derived from the Z value with respect

to a given CSI latency and numerology as described below.

[434] In other words, nCQIrefis the same as [Z/Nsob or is the smallest

value greater than or equal to [Z/Nsb], such that slot n-ncQlref corresponds to a

valid downlink slot.

[435] The description above may be applied to P/SP CSI reporting in the

same way.

[436] Next, the option 2 will be described.

[437] When a P/SP/AP CSI-RS is used to calculate CSI for A-CSI reporting,

the time offset of a CSI reference resource is derived from the Z value with respect

to a given CSI latency and numerology as described below.

[438] nCQi_ref is the same as [Z/Nsb] + 1or is the smallest value greater

than or equal to [Z/NsYb] + 1, such that slot n-ncQIref corresponds to a valid

downlink slot.

[439] The description above may be applied to P/SP CSI reporting in the

same way.

[440] In the case of the option 2, the reference resource does not at all

include symbols before 0, 1, 2, 3, . . , Z symbols at the CSI report start time.

[441] According to the current standard, since channel measurement or

interference measurement is not allowed to be performed after the reference

resource, only the option 2 already satisfies the condition of the proposal 2.

[442] Next, particulars related to aperiodic CSI report timing and CSI

relaxation will be described briefly.

[443] Candidates of CSI calculation time Z are defined in Table 7 above.

[444] While CSI is transmitted only on the PUSCH, if A-CSI reporting is

triggered on slot n, the UE doesn't have to update the CSI with respect to A-CSI

reporting for the following cases:

[445] - The case where M-L-N < Z for given CSI complexity and

numerology and

[446] - The case where an AP CSI-RS resource is transmitted on slot n for

given CSI complexity and numerology, and M-O-N < Z.

[447] Here, L represents the last symbol of the PDCCH on slot n, M

represents the start symbol of the PUSCH, and N represents the TA value (for

example, TA = 1.4 symbol) in units of symbols.

[448] And 0 represents a later symbol between the last symbol of the AP

CSI-RS resource for a channel measurement resource (CMR) and the last symbol of

the AP CSI-RS resource for an interference measurement resource (IMR).

[449] And the PUSCH timing offset for A-CSI reporting may be determined

as follows.

[450] When the PUSCH is scheduled only for a single A-CSI report, the DCI

field for the PUSCH timing offset is defined from the Y in a report setting.

[451] And when the PUSCH is scheduled only for a plurality of A-CSI reports, the DCI field for the PUSCH timing offset is defined as the maximum value among various Y values in the report setting.

[452] For example, when Y = {1, 2, 3, 6} in a report setting 1, and Y = {2, 3,

4, 5} in a report setting 2, Y may be defined as Y = {2, 3, 4, 6}.

[453] Other particulars defined in the standard will be described.

[454] The terms of low complexity CSI and high complexity CSI may be

replaced with low latency CSI and high latency CSI, respectively.

[455] Two CSI latency classes are supported for CSI computation capability.

o [456] The low latency CSI class is defined as WB CSI including a maximum

of four antenna ports, which may be applied only when a Type-I codebook or PMI is

not configured.

[457] The high latency CSI class is defined as a superset of all of CSI

supported by the UE, and the descriptions given above are not applied to L RSRP.

[458] And when CSI is transmitted through the PUSCH, a start and length

indicator value (SLIV) and PUSCH mapping type are determined by pusch

symbolAllocation in the same way as in the PUSCH without CSI.

[459] The PUSCH slot offset when CSI is multiplexed with the UL-SCH on

the PUSCH is determined solely by the K2 value indicated by pusch

symbolAllocation rather than aperiodicReportSlotOffset.

[460] The descriptions given above are applied only for the case where CSI

is multiplexed with data.

[461] Here, the numbers of candidate values for the

aperiodicReportSlotOffset and K2 are the same with each other.

[462] Particulars related to the A-CSI reporting will be further described.

[463] The condition for when the UE does not need to update CSI for A-CSI

reporting will be described again on the basis of the descriptions give above.

[464] First, an A-CSI report trigger with respect to a plurality of CSI will be

described with the A-CSI report trigger with respect to single CSI in mind.

[465] FIG. 12 illustrates one example of an A-CSI report trigger for single

CSI proposed by the present specification.

[466] More specifically, FIG. 12 illustrates an example of an A-CSI report

trigger with respect to single CSI, where a periodic CSI-RS and a CSI reference

resource exist within a time window T.

[467] In this case, the UE has to perform DCI decoding, channel estimation,

CSI calculation, and Tx preparation within the time window T.

[468] Therefore, when T < Z, the UE does not need to update the CSI.

[469] FIG. 13 illustrates one example of an A-CSI report trigger for single

CSI having a periodic CSI-RS proposed by the present specification.

[470] (Proposal1)

[471] In the case of an A-CSI report trigger for single CSI, the UE does not

update the CSI when T < Z.

[472] Here, T is a time duration between the reception time of the last

OFDM symbol of triggering DCI and the transmission time of the first OFDM symbol

of AP CSI reporting.

[473] Different from FIG. 12, even though T > Z, FIG. 13 illustrates the case

in which the P CSI-RS and the reference resource come late in the time window T.

[474] In this case, even though T > Z, the UE is unable to complete CSI

calculation since it starts channel estimation too late.

[475] Therefore, to prevent such a case from happening, the UE has to

perform channel/interference measurement at the ZP/NZP CSI-RS at which at least

Z symbols are located before the first OFDM symbol of the AP CSI report.

[476] (Proposal2)

[477] The UE does not need to measure channel or interference through

the ZP/NZP CSI-RS received from 0 to Z symbols before the transmission time of the

o first OFDM symbol of the AP CSI report.

[478] The time offset of the CSI reference resource has to be derived

properly from Z so that it matches the proposal 2.

[479] FIGs. 14 and 15 illustrate examples of a method for determining a

time offset of a CSI reference resource proposed by the present specification.

[480] More specifically, FIGs. 14 and 15 illustrate two options for

determining a time offset where Z = 5, NsOb = 14, and a CSI report starts at the 10

th symbol of slot n.

[481] FIG. 14 illustrates one example of valid CSI-RS locations for CSI

reference resource and channel measurement when nCQi_ref = [Z/NsIbl

[482] In FIG. 14, since the reference resource is slot n-1, the UE is unable

to use a potential CSI-RS resource at 1, 2, 3, or 4 symbol of slot n for channel

measurement.

[483] The UE measures the channel from a CSI-RS at one or a few slots

before the slot n.

[484] However, this operation incurs too much delay between channel

measurement and CSI report.

[485] As a result, self-contained A-CSI feedback which is performed in the

same single slot in which CSI triggering, channel measurement, and CSI report are

conducted may not be supported.

[486] To solve the aforementioned problem, as shown in FIG. 15, nCQi-ref

maybe defined as [Z/Nsobt]

[487] In other words, FIG. 15 illustrates another example of valid CSI-RS

locations for CSI reference resource and channel measurement when nCQi_ref

I slot =[Z/Ns].b

[488] In FIG. 15, the reference resource is slot n, and the slot n includes a

few symbols beyond Z.

[489] As a result, when the CSI-RS is transmitted on the 1st, 2nd, 3rd, or

4th symbol of the slot n, the UE may measure the channel by using the transmitted

CSI-RS and calculate the CSI from the new channel measurement.

[490] (Proposal3)

[491] When the P/SP/AP CSI-RS is used for CSI calculation for A-CSI

reporting, the time offset of the CSI reference resource is derived from the Z value

with respect to the CSI latency and numerology as given below.

[492] Here, nCQIref is the smallest value greater than or equal to

[Z/NsYb, such that slot n-nCQIref corresponds to a valid downlink slot.

[493] Here, a specific slot may be regarded as a valid downlink slot when

the following conditions are satisfied:

[494] - When the specific slot includes a downlink or a flexible symbol set

on at least one upper layer,

[495] - When the specific slot is not located within a measurement gap set

for the UE,

[496] - When the active DL BWP in a slot is the same as the DL BWP for

which CSI report is conducted, and

[497] - When at least one CSI-RS transmission occasion for channel

measurement and CSI-RS for interference measurement and/or CSI-IM occasion is

located in the DRS active time no later than the CSI reference resource in which the

CSI report is conducted.

[498] The description above may be applied to the P/SP CSI reporting in

the same way.

[499] When an AP CSI-RS is transmitted, a problem similar to what has

been described with reference to FIG. 13 may occur, which will be described with

reference to FIG. 16.

[500] As shown in FIG. 13, it may be seen that the AP CSI-RS comes late

in the time window T.

[501] In this case, even though T > Z, the UE is unable to complete CSI

calculation since it starts channel estimation too late.

[502] A simple method to solve this problem is to compare T' and Z instead

of T and Z.

[503] Here, T' represents a time gap between the most recent AP CSI-RS

reception time and transmission time of the first OFDM symbol of the AP CSI report.

[504] In particular, if T'< Z, the UE updates CSI and does not have to report the lowest CQI.

[505] In the case which requires more precise mechanism, Z' which is

smaller than Z is defined, and instead of T'and Z, T'and Z'may be compared.

[506] In other words, Z' indicates the amount of time required for channel

measurement, CSI calculation, and TX preparation except for DCI decoding.

[507] Z indicates the time which includes DCI decoding in addition to the

channel measurement, CSI calculation, and TX preparation.

[508] However, since the decoding time of DCI doesn't necessarily have to

be considered in the T', the time actually required for the T' may be smaller than Z.

o [509] If sufficient time is not provided for T', the UE does not have

measurement of a channel under consideration, and thus the UE may report the

lowest CQI in a specific UCI field.

[510] FIG. 16 illustrates one example of an A-CSI report trigger for single

CSI having an aperiodic CSI-RS proposed by the present specification.

[511] (Proposal 4)

[512] In the case of A-CSI report trigger for single CSI which uses an AP

CSI-RS, if T'< Z, the UE does not need to calculate CSI and reports the lowest CQI.

[513] Here, T' represents a time duration between the most recent CSI-RS

reception time and the transmission time of the first OFDM symbol for AP CSI report.

[514] In the case of A-CSI report trigger for a plurality of N CSI, if the UE is

equipped with N parallel processors, the UE may use the same mechanism as in the

single CSI trigger.

[515] However, if more than N CSI is triggered, the UE is unable to complete calculation of all of the triggered CSI.

[516] In this case, a CSI relaxation method supported by the LTE system

may be used again.

[517] (Proposal5)

[518] In other words, the proposal 5 reuses a relaxation method supported

by the LTE system in the case of an A-CSI report trigger for a plurality of CSI.

[519] Now, UE capability for CSI calculation will be described.

o [520] According to the proposals 1 to 3 described above, the amount of

time required for CSI processing is determined, which may be summarized as shown

in Tables 8 and 9.

[521] In other words, Table 8 provides Z values for normal UEs, which are

reference values that have to be supported by all of the UEs.

[522] And Table 9 provides Z values for advanced UEs; therefore, for a

given numerology and CSI latency, UE capability is employed to report whether to

support the Z values of Table 9.

[523] Also, for the given numerology and CSI latency, the Z values of Table

9 have to be the same as or smaller than the Z values of Table 8.

[524] Also, the value of Z'ij needs to be added with respect to Z'.

[525] The Z'ij value represents a required time duration between the

reception time of the most recent CSI-RS and the transmission time of the first

OFDM symbol of the AP CSI report.

[526] Table 8 illustrates one example of the CSI calculation time Z for

normal UEs.

[527] [Table 8]

CSI complexity Units 15 kHz 30 kHz 60 kHz 120 kHz SCS SCS SCS SCS

Low latency Symbols Z1,1 Z1,2 Z1,3 Z1,4 CS' High latency Symbols Z2,1 Z2,2 Z2,3 Z2,4 CSI

[528] Table 9 illustrates one example of CSI calculation time Z for advanced

UEs.

[529] [Table 9]

CSI complexity Units 15 kHz 30 kHz 60 kHz 120 kHz SCS SCS SCS SCS Low latency Symbols Z1,1 Z1,2 Z1,3 Z1,4 CSI High latency Symbols Z2,1 Z2,2 Z2,3 Z2,4 CSI

[530] The proposals described above are summarized briefly as follows.

[531] First, according to the proposal 1, if T < Z for an A-CSI report trigger

with respect to single CSI, the UE doesn't need to update CSI.

[532] Here, T represents a time duration between the reception time of the

last OFDM symbol of triggering DCI and the transmission time of the first OFDM

symbol of AP CSI reporting.

[533] And according to the proposal 2, the UE doesn't need to measure a

channel or interference due to a ZP/NZP CSI-RS received from 0 to Z symbols

before the transmission time of the first OFDM symbol of AP CSI reporting.

[534] And according to the proposal 3, when a P/SP/AP CSI-RS is used to

conduct CSI calculation for A-CSI reporting, the time offset of a CSI reference resource is derived from Z with respect to the given CSI latency and numerology as follows.

[535] In other words, nCQIrefis the smallest value greater than or equal to

[Z/Nsltb, such that slot n- ncQi_ref corresponds to a valid downlink slot. This

property may be applied in the same way to P/SP CSI reporting.

[536] And according to the proposal 4, in the case of an A-CSI report trigger

with respect to single CSI which uses an AP CSI-RS, if T' < Z, the UE doesn't need

to calculate CSI and reports the lowest channel quality indicator (CQI) to the eNB.

[537] Here, T' represents a time duration between the reception time of the

most recent AP CSI-RS and the transmission time of the first OFDM symbol of the

AP CSI report.

[538] And the proposal 5 reuses a relaxation method supported by the LTE

system in the case of an A-CSI report trigger for a plurality of CSI.

[539] Next, another embodiment will be described.

[540] The time offset of a CSI reference resource is derived from Z' with

respect to the CSI latency and numerology given as follows.

[541] nCQi_ref is the smallest value greater than or equal to [Z'/Nsb], such

that slot n- ncQIref corresponds to a valid downlink slot.

[542] Or nCQirefmay be interpreted to be the same as [Z'/Ns'bj or to be

the smallest value among those values larger than [Z'/Nsmb, such that slot n nCQi_refcorresponds to a valid downlink slot. This property may also be applied to at

least aperiodic CSI report.

[543] And this property is applied when an AP/P/SP CSI-RS is used for CSI calculation.

[544] When a P/SP CSI-RS and/or CSI-IM is used for channel or interference measurement, the UE does not expect the last OFDM symbol to measure a channel and/or interference with respect to the CSI-RS and/or CSI-IM received from 0 to Z'symbols before the transmission time of the first OFDM symbol of the AP CSI reporting.

[545] The aforementioned property is not the only condition, and the CSI RS has to be defined at or before the CSI reference resource. This property also includes the case of the AP CSI-RS.

[546] In the case of the AP CSI report, when the P/SP CSI-RS is used for channel and/or interference measurement, the UE does not expect the most recent CSI-RS to be received later than the CSI reference resource before triggering of the PDCCH.

[547] In Table 10 below, (Z, Z') values are reference values that have to be supported by all of the UEs.

[548] For normal UEs, it has not been determined yet about whether the (Z, Z') values with respect to low latency CSI and high latency CSI of Table 10 below are the same with each other for given numerology.

[549] If the two values are the same with each other for all of the numerology, low latency and high latency are combined to normal UEs.

[550] In Table 11 below, whether to support (Z, Z') values of Table 11 with respect to given numerology and CSI latency is reported to the eNB through UE capability.

[551] For the given numerology and CSI latency, the (Z, Z') values of Table

11 haves to be equal to or smaller than the (Z, Z') values of Table 10.

[552] Table 10 illustrates CSI calculation time Z for normal UEs.

[553] [Table 10]

Units 15kHz SCS 30kHz SCS 60kHz SCS 120kHz CSI latency ScS Low latency Symbols (Z1,1, Z'1,1) (Z1, 2 , Z'1, 2 ) (Z1, 3 , Z'1, 3 ) (Z1, 4 , Z'1, 4

) High latency Symbols (Z2 ,1, Z' 2 ,1) (Z 2 ,2 , Z' 2 ,2 ) (Z2 ,3 , Z' 2 ,3 ) (Z 2 ,4 , Z' 2 ,4

)

[554] Table 11 illustrates CSI calculation time Z for advanced UEs.

[555] [Table 11]

Units 15kHz SCS 30kHz SCS 60kHz SCS 120kHz CSI latency ScS Low latency Symbols (Z1,1, Z'1,1) (Z1, 2 , Z'1, 2 ) (Z1, 3 , Z'1, 3) (Z1, 4 , Z'1, 4

) High latency Symbols (Z2 ,1, Z' 2 ,1) (Z 2,2 , Z' 2 ,2 ) (Z 2 ,3 , Z' 2,3) (Z2 ,4 , Z' 2 ,4

)

[556] As yet another embodiment, a mechanism related to CSI reporting

will be described further.

[557] More specifically, CSI reporting timing and UE capability related

thereto will be described.

[558] In what follows, through Tables 12 and 13, specific values of (Z, Z') for

a normal UE and an advanced UE will be examined.

[559] For the Z' value of a normal UE, it is assumed that the UE performs

CSI measurement/calculation and channel multiplexing; and CSI encoding and

modulation for the Z'symbol.

[560] Part of CSI measurement and calculation depends on the numerology

and requires 6 * 2 (p- 2 ) symbols; the remaining portions and channel

multiplexing/CSI encoding/modulation uses 20 symbols respectively for a high latency and 13 symbols for a low latency.

[561] As a result, Z'for the low latency and the high latency is 13 + 6 * 2 A

(p-2)and 20+ 6 * 2A (p-2).

[562] For the Z value of a normal UE, it is assumed that a CSI-RS is

located at the next symbol of a final PDCCH symbol.

[563] Also, it is assumed that CSI processing may start after DCI decoding.

[564] The DCI decoding time requires 4 + 10 * 2 A (p- 2 ) including a portion

depending on a numerology such as PDCCH CE/demultiplexing/decoding and a

portion independent of the numerology.

o [565] As a result, Z is determined by DCI decoding time + CSI processing

time, namely 4 + 10 * 2 (p-2) + Z'.

[566] In the case of an advanced UE, since DCI decoding is conducted for

5 symbols, Z' is 7 symbols and 14 symbols, respectively for a low latency and a high

latency; and Z is Z'+5.

[567] Table 12 represents CSI calculation time (Z, Z') for a normal UE.

[568] [Table 12] CSI latency Units 15kHz SCS 30kHz SCS 60kHz SCS 120kHz (P = 0) (P = 1) (p = 2) SCS (p = 3)

Low latency Symbols (22, 15) (25, 16) (33, 19) (49,25)

High latency Symbols (29,22) (32,23) (40,26) (56,32)

[569] Table 13 represents CSI calculation time (Z, Z') for an advanced UE.

[570] [Table 13] CSI latency Units 15kHz SCS 30kHz SCS 60kHz SCS 120kHz (P = 0) (P = 1) (p = 2) SCS (p = 3)

Low latency Symbols (12,7) (12,7) (12,7) (12,7)

High latency Symbols (19, 14) (19, 14) (19, 14) (19, 14)

[571] Various proposals related to the descriptions above will be examined.

[572] The proposals to be described later may be applied separately from

the proposals described above or applied together with the aforementioned

proposals.

[573] (Proposal 1')

[574] As the minimum required CSI processing time for a normal and an

advanced UEs, the (Z, Z') values of Tables 12 and 13 above are selected,

respectively.

o [575] Regarding CSI and data multiplexing, one remaining problem is the

number of symbols required for a UE to complete CSI processing and data encoding

simultaneously.

[576] When CSI and data are multiplexed, allocation of a data resource

element (RE) depends on a CSI payload; however, CSI/payload size is varied

according to CRI/RI/amplitude coefficient other than 0, or the number of CSI

omission.

[577] As a result, CSI processing and data encoding may not be performed

in a fully parallel manner.

[578] More specifically, in the case of type I CSI, CRI/RI of Part 1

determines the payload size of Part 2 CSI such as PMI and CQI.

[579] In the case of type II CSI, the number of non-zero amplitude

coefficients of RI/Part 1 CSI determines the payload size of Part 2 CSI such as PMI

and CQI.

[580] Therefore, when CSI and data are multiplexed, instead of (Z, Z'), the

UE requires at least (Z+C, Z'+C) symbol to prepare CSI and data simultaneously.

[581] Here, C is smaller than or equal to N2.

[582] (Proposal 2')

[583] When AP CSI and data for a PUSCH are multiplexed, the UE is not

expected to receive scheduling DCI having a symbol offset such that M-L-N < Z+C.

[584] Here, L represents the last symbol of a PDCCH triggering an A-CSI

report, L is a start symbol of a PUSCH, N is a TA value in symbol units, and C is

equal to or smaller than N2.

o [585] (Proposal 3')

[586] When AP CSI and data for a PUSCH are multiplexed, and an AP CSI

RS is used for channel measurement, the UE is not expected to receive scheduling

DCI having a symbol offset such that M-O-N < Z'+C.

[587] Here, N represents a TA value in symbol units; 0 represents a value

which comes late among the last symbol of an AP CSI-RS resource for a CMR, the

last symbol of an aperiodic NZP CSI-RS for an IM (if exists), and the last symbol of

an aperiodic CSI-IM (if exists); and C is equal to or smaller than N2.

[588] Also, when AP CSI and data for a PUSCH are multiplexed, although

the time position of a CSI reference resource is determined in the same manner for

the AP CSI only case, the time position is determined based on Z'+C instead of Z'.

[589] (Proposal 4')

[590] When AP CSI and data for a PUSCH are multiplexed, a time offset of

a CSI reference resource is derived from Z'+C with respect to a given CSI latency

and a numerology.

[591] The time offset of a CSI reference resource is derived from Z' with

respect to a given CSI latency and a numerology as follows.

[592] nCQIref is the smallest value greater than or equal to [(Z' +C)/Nslbt

such that slot n-ncQIrefcorresponds to a valid downlink slot.

[593] When a P/SP CSI-RS and/or CSI-IM is used for channel

measurement and/or interference measurement, the UE does not expect the last

OFDM symbol to measure a channel and/or interference with respect to the CSI-RS

and/or CSI-IM received from 0 to Z'+C symbols before the transmission time of the

first OFDM symbol of an AP CSI report.

o [594] Another issue is calculation time for a beam report, namely CRI and

layer 1 reference signal received power (L1 RSRP).

[595] When Li RSRP is power measurement of a single port, and the same

calculated power is used for a CSI report and a beam report, it is preferable to

regard the Li RSRP as low latency CSI.

[596] Also, to reduce calculation complexity, the number of CSI-RS

resources for a beam report may be limited.

[597] (Proposal 5')

[598] The same (Z, Z') is applied for a beam report from low latency CSI as

in the CSI report.

[599] Next, in the case of an A-CSI report trigger for a plurality of N CSI, if

the UE is equipped with X parallel processors, and X>N, the same mechanism as a

single CSI report trigger may be used without relaxation.

[600] However, if more than X CSIs are triggered, the UE is unable to complete the calculation for all of the triggered CSIs.

[601] In this case, a relaxation method supported in the LTE system may be

reused.

[602] In particular, if the UE does not have an unreported CSI(s), and N > X,

the UE does not necessarily have to calculate N-X CSI(s).

[603] (Proposal 6')

[604] In the case of an A-CSI report trigger for a plurality of CSI, a

relaxation method supported in the LTE system may be reused.

o [605] More specifically, if the UE is equipped with X parallel CSI processors

and have N unreported CSI(s), and N > X, the UE does not necessarily have to

update N-X most recent CSI(s).

[606] Regarding the time position of a reference resource for P/SP CSI

reporting, the same method for the time position of a reference resource for AP CSI

reporting may be applied.

[607] (Proposal 7')

[608] The reference resource time position for P/SP CSI reporting may be

determined by the same method for the reference resource time position for AP CSI

reporting.

[609] Particulars related to CSI relaxation will be described in more detail.

[610] X represents capability for the maximum number of CSIs that may be

updated simultaneously.

[611] If CSI processing time intervals of N (> X) CSI reports overlap with each other in the time domain, the UE does not need to update N-X CSI reports.

[612] A CSI processing time interval is a time interval which ranges from

the start of a symbol S to the last of a symbol E.

[613] Here, regarding periodic and semi-persistent CSI reporting,

[614] (1) In the case of Alt. 1,

[615] S is a start symbol of a CQI reference resource slot.

[616] (2) In the case of Alt. 2,

[617] S is E-Z'(or E-(Z'+1)), and E is a start symbol of a CSI report.

[618] Since the NR sets the location of a channel measurable CSI-RS at

the symbol level (in other words, a CSI-RS located at a symbol below E-Z' or at a

symbol below E-(Z'+1) is measured), Alt. 2 proposes the latest time at which CSI

processing may be started.

[619] In other words, the UE may start CSI processing at the time S of Alt. 2

at the latest.

[620] (3) In the case of Alt. 3,

[621] S is the location of the start symbol of a CSI report - Z' (or start

symbol of a CSI report - (Z'+1)) or the last symbol of the CSI-RS (which is used for

calculation of the corresponding CSI) received at the most recent time point among

the time points before the start symbol.

[622] Since the UE starts CSI calculation by using the CSI-RS at the

aforementioned time point, the UE is appropriate for S and satisfies that E = S + Z'.

[623] Next, regarding a CSI report and a CSI-IM having a periodic or semi

persistent CSI-RS,

[624] (1) In the case of Alt. 1,

[625] If a reference resource is located before a PUCCH with aperiodic CSI triggering, S becomes the last symbol of the PDCCH with aperiodic CSI triggering, and E = S+Z.

[626] Otherwise, S = E-Z', and E is the start symbol of a CSI report.

[627] (2) In the case of Alt. 2,

[628] If the start symbol of a CSI report - Z' (or start symbol of a CSI report

- (Z'+1)) is located before the PDCCH with aperiodic CSI triggering, S is the last

symbol with aperiodic CSI triggering (or S is the last symbol of the PDCCH with

aperiodic CSI triggering + 1), and E = S + Z.

[629] In other words, if a measurable CSI-RS is received before the

o PDCCH, the UE may start CSI calculation after receiving the PDCCH.

[630] Since the minimum required time until a CSI report is completed after

reception of the PDCCH is Z, the time at which the CSI calculation is finished

becomes S+Z.

[631] Otherwise, S is E-Z' (or E-(Z'+1)), and E is the start symbol of a CSI

report.

[632] In other words, if a measurable CSI-RS is received after the PDCCH,

the UE may start CSI calculation after receiving the CSI-RS.

[633] Since the minimum required time until the CSI report is completed

after reception of the CSI-RS is Z', the time at which CSI calculation is finished

becomes S+Z'.

[634] (3) In the case of Alt. 3,

[635] Suppose the most recent CSI-RS received at or before the start

symbol of CSI report - Z' (or start symbol of CSI report - (Z'+1)) is a 'reference CSI

RS'. If the last symbol of a reference CSI-RS is located before the PDCCH with

aperiodic CSI triggering, S becomes the last symbol of the PDCCH with aperiodic

CSI triggering (or last symbol of the PDCCH with aperiodic CSI triggering + 1), and E

= S + Z.

[636] In other words, if a measurable CSI-RS is received before the

PDCCH, the UE may start CSI calculation after receiving the PDCCH.

[637] Since the minimum required time until a CSI report is completed after

reception of the PDCCH is Z, the time at which CSI calculation is finished becomes

S + Z.

[638] Otherwise, S = E-Z' (or E-(Z'+1)), and E is the start symbol of a CSI

report.

[639] In other words, if a measurable CSI-RS is received after the PDCCH,

the UE may start CSI calculation after receiving the CSI-RS.

[640] Since the minimum required time until a CSI report is completed after

receiving the CSI-RS is Z', the time at which CSI calculation is finished becomes S

+ Z'.

[641] (4) In the case of Alt. 4,

[642] S is E-Z' (or E-(Z'+1)), and E is the start symbol of a CSI report.

[643] Next, regarding an aperiodic CSI report with an aperiodic CSI-RS and

a CSI-IM,

[644] S1 is the last symbol of a PDCCH with aperiodic CSI triggering.

[645] S2 is the symbol which comes late among the last symbol of an

aperiodic CSI-RS with respect to a CMR, the last symbol of the aperiodic CSI-RS

with respect to an IMR, and the last symbol of the aperiodic CSI-IM.

[646] (1) In the case of Alt. 1,

[647] If S1 + Z > S2 + Z' (in other words, if the location of an OFDM symbol added by Z symbols in S1 lies after the OFDM symbol location added by Z'symbols in S2), S=S1, and E=S1 +Z.

[648] Otherwise, S = S2, and E = S2 + Z'.

[649] The UE terminates CSI processing at a later time between S1 + Z

and S2 + Z'.

[650] Therefore, E is set to the later of the two, and the start time of which

is completed later between the two is assumed to be the start of CSI processing.

[651] (2) In the case of Alt. 2,

[652] It is set such that S = S2.

o [653] If S1 + Z > S2 + Z (in other words, if the location of an OFDM symbol

added by Z symbols in S1 lies after the OFDM symbol location added by Z'symbols

in S2), E = S1 + Z. Otherwise, E = S2 + Z'.

[654] Here, the end time of CSI processing in Alt. 2 is the same as that of

Alt. 1, but the start time is fixed to S2 which is used for channel and/or interference

estimation.

[655] This is so because an AP CSI-RS is always restricted to be received

after reception of a PDCCH, and in this case, the UE is able to start CSI processing

at least when the reception of the CSI-RS is completed.

[656] (3) In the case of Alt. 3,

[657] S is E-Z' (or E-(Z'+1)), and E is the start symbol of a CSI report.

[658] When CSI is calculated by using a P/SP CSI-RS and/or CSI

Interference Measurement (IM), a plurality of measurable CSI-RSs may exist in the

time domain.

[659] The UE may calculate CSI by measuring a CSI-RS received as recently as possible with respect to a CSI reporting time, thereby obtaining fresh CSI.

[660] At this time, too, a CSI-RS located before reporting time - Z' has to

be measured by taking into account the CSI calculation time of the UE.

[661] However, if the CSI (which is called 'CSI 1') calculation time overlaps

with other CSI (which is called 'CSI 2') calculation time, and the number of CSIs that

may be calculated at the same time is exceeded, the UE is unable to calculate part

of CSIs.

[662] To solve the problem above, the calculation time of CSI 1 may be put

to an earlier time so that it may not be overlapped with the CSI 2.

o [663] This is possible since the CSI 1 is calculated by using a P/SP CSI-RS

and/or CSI-IM, a plurality of P/SP CSI-RSs and/or CSI-IMs exist along the time axis,

and thereby the CSI 1 may be calculated in advance by using the P/SP CSI-RS

and/or CSI-IM received previously.

[664] However, it should be noted that if the CSI 1 is calculated too early, a

potential interval is introduced to avoid a situation where CSI is outdated, and the

CSI 1 may be calculated in advance by using the P/SP CSI-RS and/or CSI-IM

received within the potential interval.

[665] A potential interval (namely the N value proposed below) may be

determined by the eNB and indicated for the UE; or the UE may determine the

potential interval and report the determined potential interval to the eNB.

[666] The potential interval is terminated at "reporting time - Z' and starts

at the end time - N time.

[667] When a plurality of CSIs are reported through the same PUSCH,

channel multiplexing/encoding/modulation is performed simultaneously to a plurality

of the corresponding CSIs, and therefore, a smaller amount of processing time is required than the case where a plurality of CSIs are reported through a different

PUSCH.

[668] Therefore, when a plurality of CSIs are reported through the same

PUSCH, one of the CSIs requires CSI processing time T, but the remaining CSI(s)

requires only the time needed for "T - channel multiplexing/encoding/modulation".

[669] Therefore, when processing time is defined for CSI relaxation, the

remaining CSI is defined as"T-channel multiplexing/encoding/modulation", and as a

result, the possibility that the processing time overlaps with other CSI may be

reduced.

[670] And when channel and/or interference is measured by using a

periodic or semi-persistent CSI-RS, a plurality of measurable CSI-RSs may exist

along the time axis.

[671] In this case, the UE calculates CSI by measuring a CSI-RS existing

before Z' (or Z'+1) symbol with reference to the first OFDM symbol which starts CSI

reporting.

[672] Therefore, the latest time at which the UE measures CSI for CSI

calculation becomes "the symbol before Z' (or Z'+1) symbols with reference to the

first OFDM symbol which starts CSI reporting".

[673] Therefore, it is preferable to set the start time of CSI processing as

"the symbol before Z' (or Z'+1) symbols with reference to the first OFDM symbol

which starts CSI reporting".

[674] And it is preferable to set the end time of CSI processing as the first

OFDM symbol which starts CSI reporting.

[675] On the other hand, when channel and/or interference is measured by using an aperiodic CSI-RS, one measurable CSI-RS may exist along the time axis.

[676] Therefore, it is preferable to set the start time of CSI processing as

"the very last symbol at which an AP CSI-RS and/or AP CSI-IM is received".

[677] In the case of periodic or semi-persistent CSI reporting, a reporting

time is defined in advance.

[678] Therefore, the UE knows the location of a recent CSI-RS existing

before Z' (or Z'+1) symbol with reference to the first OFDM symbol which starts CSI

reporting.

[679] Therefore, since calculation may be started from the corresponding

CSI-RS, S becomes the last OFDM symbol of the corresponding CSI-RS, and E

becomes S+Z'.

[680] In the case of AP CSI reporting, when an AP CSI-RS is used, one

CSI-RS used for CSI calculation exists along the time axis.

[681] It should be noted that since a CSI-RS for CMR uses is different from

a CSI-RS for IMR uses, there exist one CSI-RS for each use along the time axis.

[682] Therefore, since calculation may be started from the corresponding

CSI-RS, S becomes the last OFDM symbol of the corresponding CSI-RS, and E

becomes S+Z'.

[683] In the case of AP CSI reporting, when a P/SP CSI-RS is used, the

most recent CSI-RS used for CSI calculation may be received before DCI.

[684] Therefore, if the last OFDM symbol of the corresponding CSI-RS is

set to S, the UE starts to calculate CSI at a time at which it is uncertain whether the

corresponding CSI may be triggered or not.

[685] If the corresponding CSI is not triggered, the UE wastes computation power, and a problem may arise, such that the corresponding computation power is not used for other CSI calculation.

[686] To solve the problem above, S is defined such that S = E-Z', and E is

defined as the first symbol of PUSCH CSI reporting.

[687] Various combinations are possible for S and E proposed in the

different Alt.s, above, and corresponding combinations are also applicable to a

method proposed by the present specification.

[688] For example, S and E may be determined by the S of Alt. 1 and the E

o of Alt. 2.

[689] And in the proposals 2 and 3 above, Z'may be replaced with Z'-1.

[690] Since the UE may still be able to calculate CSI even if Z'time is given,

which ranges from a CSI-RS and/or CSI-IM to the start symbol of CSI reporting, Z'

may be replaced with Z'-1.

[691] For the same reason, in the proposal 4 above, Z' may be replaced

with Z'-1.

[692] Method for operating a UE and an eNB

[693] In what follows, operations of a UE and an eNB for performing the

method above proposed in the present specification will be described with reference

to FIGs. 17 to 23.

[694] FIG. 17 is a flow diagram illustrating one example of a method for

operating a UE which performs CSI reporting proposed by the present specification.

[695] First, the UE receives downlink control information (DCI) triggering an aperiodic CSI report from the eNB S1710.

[696] And the UE determines a CSI reference resource related to the

aperiodic CSI report S1720.

[697] The CSI reference resource may be determined to a slot n-ncQIref in

the time domain.

[698] More specifically, the ncarefmay be the smallest value equal to or

greater than floor(a first parameter/a second parameter) so that the slot n-ncQIref

corresponds to a valid downlink slot.

[699] Here, a specific slot may be regarded as a valid downlink slot when

the following conditions are satisfied:

[700] - The case where the specific slot includes a downlink or flexible

symbol set to at least one upper layer,

[701] - The case where the specific slot is not located within a

measurement gap configured for the UE,

[702] - The case where an active DL BWP in the slot is the same as a DL

BWP in which a CSI report is conducted, and

[703] - The case where there exists at least one CSI-RS transmission

occasion and CSI-RS and/or CSI-IM occasion for interference measurement at a

DRS active time no later than a CSI reference resource at which a CSI report is

conducted.

[704] Here, the first parameter may be related to the time for computation

of the CSI, and the second parameter may represent the number of symbols within

one slot.

[705] More specifically, the first parameter may be represented by a specific

number of symbols (Z'), and the second parameter may be represented by Nsb

[706] And the second parameter is 14.

[707] And the first parameter may be determined based on a CSI latency

and a numerology.

[708] The CSI latency may be represented by a CSI computation delay.

[709] And the UE reports the CSI to the eNB on slot n based on the CSI

reference resource S1730.

[710] In addition, the UE receives, from the eNB, an aperiodic CSI-RS.

[711] And the UE computes the CSI based on the aperiodic CSI-RS and the CSI

reference resource.

o [712] It is preferable to conduct the process for computing the CSI before

the S1730 step.

[713] Here, the aperiodic CSI-RS may be received after the DCI.

[714] Also, the UE may transmit capability information including the first

parameter to the eNB before the S1710 step.

[715] The DCI may be received in a slot other than the slot n.

[716]

[717] The operation of the UE of FIG. 17 may be interpreted as follows.

[718] The UE receives, from a base station (BS), downlink control

information (DCI) related to an aperiodic CSI report that is to be performed by the UE

in a slot n.

[719] And, the UE determines a value ncQI-ref based on a number of

symbols Z' related to a time for computing the CSI.

[720] And, the UE determines a CSI reference resource as being a slot n

ncQI-ref in a time domain that is to be used for the aperiodic CSI report.

[721] And, the UE transmits, to the BS, the aperiodic CSI report in the slot n, based on the CSI reference resource being slot n - ncQ,_re-f

[722] The ncQ,_ref is a smallest value greater than or equal to z' slot . /symbJ

such that the slot n - ncQI-ref satisfies a valid downlink slot criteria.

[723] Here, Jis a floor function and Nslma is a number of symbols in

one slot.

[724] The valid downlink slot criteria is based at least on (i) the number of

symbols Z' related to the time for computing the CSI and (ii) a DCI processing time.

[725] The N, "mb is equal to 14 symbols in a slot.

[726] Additionally, the UE may receive, from the BS, an aperiodic reference

signal (CSI-RS) in the CSI reference resource, slot n - ncQi-ref, and determine the

CSI based on the aperiodic CSI-RS, and generate the aperiodic CSI report based on

the CSI.

[727] And, the UE may determine the number of symbols Z' related to the

time for computing the CSI based on a CSI complexity and a subcarrier spacing.

[728] The number of symbols Z' does not include a DCI processing time.

[729] And, the UE determines the value ncQi-ref based on the number of

symbols Z' related to the time for computing the CSI, and further based on a

number of symbols in one slot.

[730] Also, the UE may receive the DCI in a slot other than the slot n in

which the aperiodic CSI report is to be performed.

[731] Also, based on the value ncQi-ref being equal to zero, the aperiodic

CSI report may be performed in a same slot as receiving the DCI.

[732]

[733] FIG. 18 is a flow diagram illustrating one example of a method for

operating an eNB which receives a CSI report proposed by the present specification.

[734] First, the eNB transmits downlink control information (DCI) triggering

an aperiodic CSI report to the UE S1810.

[735] And the eNB receives, from the UE, the aperiodic CSI report on slot n

S1820.

[736] Here, the aperiodic CSI report is related to a CSI reference resource,

and the CSI reference resource may be determined to a slot n - ncai_refin the time

domain.

[737] At this time, the ncaIrefmay be the smallest value equal to or greater

than floor (a first parameter/a second parameter) so that the slot n-ncaref

corresponds to a valid downlink slot.

[738] Here, the first parameter may be related to the time for computation

of the CSI, and the second parameter may represent the number of symbols within

one slot.

[739] More specifically, the first parameter may be represented by a specific

number of symbols (Z'), and the second parameter may be represented by Nsb

[740] And the second parameter is 14.

[741] And the first parameter may be determined based on a CSI latency

and a numerology.

[742] The CSI latency may be represented by a CSI computation delay.

[743] In addition, the eNB may transmit an aperiodic CSI-RS to the UE.

[744] At this time, the aperiodic CSI-RS may be transmitted to the UE after

the DCI.

[745] And the eNB may receive, from the UE, capability information

including the first parameter before the S1810 step.

[746] Here, the DCI may be transmitted from a slot other than the slot n.

[747] Referring to FIGs 19 to 23 to be described later, a process by which a

method for reporting CSI proposed in the present specification is implemented in a

UE will be described in more detail.

[748] First, in a wireless communication system, a UE for reporting CSI

may comprise an Radio Frequency (RF) module for transmitting and receiving a

radio signal; and a processor operatively connected to the RF module.

[749] The RF module of the UE receives, from the eNB, downlink control

information (DCI) triggering an aperiodic CSI report.

[750] And the processor controls the UE to determine a CSI reference

resource related to the aperiodic CSI report.

[751] The CSI reference resource may be determined to a slot n - nCQi_ref in

the time domain.

[752] The ncairefmay be determined based on a first parameter related to

the time for computing the CSI.

[753] And the first parameter may be determined based on a CSI latency

and a numerology.

[754] The CSI latency may be represented by a CSI computation delay.

[755] More specifically, the ncarefmay be the smallest value equal to or

greater than floor(a first parameter/a second parameter) so that the slot n-ncQIref

corresponds to a valid downlink slot.

[756] The second parameter may represent the number of symbols within

one slot.

[757] More specifically, the first parameter may be represented by a specific

number of symbols (Z'), and the second parameter may be represented by Nsb

[758] And the second parameter is 14.

[759] Now, a specific method for computing a ncai_ref value by the UE will

be described with reference to FIG. 19.

[760] In other words, FIG. 19 illustrates one example of a method for

implementing a nCQI_refvalue proposed in the present specification.

[761] First, the memory of a UE stores a predefined second parameter.

[762] And the processor of the UE may compute the ncai_ref value by using

an input first parameter value and a second parameter value stored in the memory.

[763] The first parameter value is determined based on a CSI latency (or

o CSI computation delay) and a numerology (p).

[764] As shown in FIG. 19, in the case of CSI latency 1, if the numerology

(p) is 0, 1, 2, and 3, the first parameter value is 8, 11, 21, and 36, respectively, and

the ncaIrefvalue corresponding thereto is 0, 0, 1, and 2.

[765] And in the case of CSI latency 2-1, if the numerology (p) is 0, 1, 2,

and 3, the first parameter value is 16, 30, 42, and 85, respectively, and the ncai_re

value corresponding thereto is 1, 2, 3, and 6.

[766] And in the case of CSI latency 2-2, if the numerology (p) is 0, 1, 2,

and 3, the first parameter value is 37, 69, 140, and 140, respectively, and the ncai_re

value corresponding thereto is 2, 4, 10, and 10.

[767] And the RF module of the UE reports the CSI to the eNB on slot n

based on the CSI reference resource.

[768] In addition, the RF module of the UE receives, from the eNB, an

aperiodic CSI-RS.

[769] And the processor of the UE computes the CSI based on the

aperiodic CSI-RS and the CSI reference resource.

[770] It is preferable that the processor of the UE performs computation of

CSI before the RF module of the UE reports the CSI.

[771] Here, the aperiodic CSI-RS may be received after the DCI.

[772] Also, the RF module of the UE may transmit capability information

including the first parameter to the eNB before receiving the DCI.

[773] The DCI may be received in a slot other than the slot n.

[774] Referring to FIGs. 19 to 23 to be described later, a process by which

a method for reporting CSI proposed in the present specification is implemented in

an eNB will be described in more detail.

[775] First, in a wireless communication system, an eNB for receiving a CSI

report may comprise a Radio Frequency (RF) module for transmitting and receiving

a radio signal; and a processor operatively connected to the RF module.

[776] First, the RF module of the eNB transmits to the UE downlink control

information (DCI) triggering an aperiodic CSI report.

[777] And the RF module of the eNB receives, from the UE, the aperiodic

CSI report on a slot n.

[778] Here, the aperiodic CSI report is related to a CSI reference resource,

and the CSI reference resource may be determined to a slot n - ncai_refin the time

domain.

[779] At this time, the ncaIrefmay be the smallest value equal to or greater

than floor(a first parameter/a second parameter) so that the slot n-ncaref

corresponds to a valid downlink slot.

[780] Here, the first parameter may be related to time for computing the

CSI, and the second parameter may represent the number of symbols in one slot.

[781] More specifically, the first parameter may be represented by a specific

number of symbols (Z'), and the second parameter may be represented by Nsb

[782] And the second parameter may be 14.

[783] And the first parameter may be determined based on a CSI latency

and a numerology.

[784] The CSI latency may be represented by a CSI computation delay.

[785] In addition, the RF module of the UE may transmit an aperiodic CSI

RS to the UE.

[786] At this time, the aperiodic CSI-RS may be transmitted to the UE after

o the DCI.

[787] And the RF module of the eNB may receive capability information

including the first parameter from the UE before transmitting the DCI.

[788] Here, the DCI may be transmitted from a slot other than the slot n.

[789] The device to which the present disclosure may be applied in

general

[790] FIG. 20 illustrates a block diagram of a wireless communication

device to which methods proposed by the present specification may be applied.

[791] Referring to FIG. 20, a wireless communication system comprises an

eNB 2010 and a plurality of UEs 2020 located within the range of the eNB 3510.

[792] The eNB and the UEs may be represented by wireless devices,

respectively.

[793] The eNB comprises a processor 2011, memory 2012, and Radio

Frequency (RF) unit 2013. The processor 2011 implements the functions,

processes and/or methods described with reference to FIGs. 1 to 19. Layers of a wireless interface protocol may be implemented by the processor. The memory, being connected to the processor, stores various kinds of information to operate the processor. The RF unit, being connected to the processor, transmits and/or receives a radio signal.

[794] The UE comprises a processor 2021, memory 2022, and RF unit

2023.

[795] The processor implements the functions, processes and/or methods

described with reference to FIGs. 1 to 19. Layers of a wireless interface protocol

may be implemented by the processor. The memory, being connected to the

processor, stores various kinds of information to operate the processor. The RF

unit, being connected to the processor, transmits and/or receives a radio signal.

[796] The memory 2012, 2022 may be installed inside or outside the

processor 2011, 2021 and may be connected to the processor via various well

known means.

[797] Also, the eNB and/or the UE may be equipped with a single antenna

or multiple antennas.

[798] The antenna 2014, 2024 performs the function of transmitting and

receiving a radio signal.

[799] FIG. 21 illustrates a block diagram of a communication device

according to one embodiment of the present disclosure.

[800] In particular, FIG. 21 provides further details of the UE of FIG. 20.

[801] Referring to FIG. 21, the UE may comprise a processor (or digital

signal processor (DSP)) 2110, RF module (or RF unit) 2135, power management

module 2105, antenna 2140, battery 2155, display 2115, keypad 2120, memory

2130, Subscriber Identification Module (SIM) card 2125 (this element is optional),

speaker 2145, and microphone 2150. The UE may also include a single antenna or

multiple antennas.

[802] The processor 2110 implements the functions, processes and/or

methods described with reference to FIGs. 1 to 19. Layers of a wireless interface

protocol may be implemented by the processor.

[803] The memory 2130 is connected to the processor and stores

information related to the operation of the processor. The memory may be installed

inside or outside the processor and may be connected to the processor via various

well-known means.

[804] The user, for example, enters command information such as a phone

number by pushing (or touching) the button of the keypad 2120 or via voice

activation by using the microphone 2150. The processor receives the command

information and processes the command to perform an appropriate function such as

making a phone call to the phone number. Operational data may be extracted from

the SIM card 2125 or memory 2130. Also, the processor may recognize the user

and for the convenience of the user, may display command information or

operational information on the display 2115.

[805] The RF unit 2135, being connected to the processor, transmits and/or

receives an RF signal. The processor delivers command information to the RF

module to initiate communication, for example, to transmit a radio signal comprising

voice communication data. The RF module is composed of a receiver and a

transmitter for receiving and transmitting a radio signal. The antenna 2140

performs the function of transmitting and receiving a radio signal. When receiving a

radio signal, the RF module delivers a signal and transforms the signal into the baseband so that the processor may process the signal. The processed signal may be converted to audible information output through the speaker 2145 or readable information.

[806] FIG. 22 illustrates one example of an RF module of a wireless

communication device to which a method proposed by the present specification may

be applied.

[807] More specifically, FIG. 22 illustrates one example of an RF module

which may be implemented in a Frequency Division Duplex (FDD) system.

o [808] First, along the transmission path, the processor shown in FIGs. 20

and 21 processes data to be transmitted and provides an analog output signal to the

transmitter 2210.

[809] Within the transmitter 2210, the analog output signal is filtered by the

low pass filter (LPF) 2211 to remove images caused by the analog-to-digital

converter (ADC), up-converted to an RF band from the baseband by the mixer 2212,

and amplified by the variable gain amplifier (VGA) 2213; the amplified signal is

filtered by the filter 2214, additionally amplified by the power amplifier (PA) 2215,

routed through a duplexer(s) 2250/antenna switch(es) 2260, and transmitted through

the antenna 2270.

[810] Also, along the reception path, the antenna receives signals from the

outside and provides the received signals, which are routed through the antenna

switch(es) 2260/duplexers 2250 and are provided to the receiver 2220.

[811] Within the receiver 2220, received signal are amplified by the low noise

amplifier (LNA) 2223, filtered by the bandpass filter 2224, and down-converted to the

baseband from the RF band by the mixer 2225.

[812] The down-converted signal is filtered by the low pass filter (LPF) 2226,

amplified by the VGA 2227 to acquire the analog input signal, which is provided to

the processor illustrated in FIGs. 20 and 21.

[813] Also, the local oscillator (LO) 2240 generates transmission and

reception LO signals and provides the generated signals to the up converter 2212

and down converter 2225, respectively.

[814] Also, the phase locked loop (PLL) 2230 receives control information

from the processor to generate transmission and reception LO signals at appropriate

frequencies and provides the control signals to the LO generator 2240.

o [815] Also, the circuits shown in FIG. 22 may be arranged differently from

the structure of FIG. 22.

[816] FIG. 23 illustrates another example of an RF module of a wireless

communication device to which a method proposed by the present specification may

be applied.

[817] More specifically, FIG. 23 illustrates one example of an RF module

which may be implemented in a Time Division Duplex (TDD) system.

[818] The transmitter 2310 and the receiver 2320 of the RF module in the

TDD system have the same structures as those of a transmitter and a receiver of an

RF module in the FDD system.

[819] In what follows, only the structure of the RF module in the TDD

system which exhibits a difference from the RF module in the FDD system will be

illustrated, and the same structure thereof will be described with reference to FIG. 22.

[820] A signal amplified by the power amplifier 2315 of the transmitter is

routed via the band select switch 2350, bandpass filter (BPF) 2360, and antenna switch(es) 2370; and is transmitted through the antenna 2380.

[821] Also, along the reception path, the antenna receives signals from the

outside, provides the received signals. The signals are routed via the antenna

switch(es) 2370, BPF 2360, and band select switch 2350; and are provided to the

receiver 2320.

[822] The embodiments described above are combinations of constituting

elements and features of the present disclosure in a predetermined form. Each

individual element or feature has to be considered as optional except where

otherwise explicitly indicated. Each individual element or feature may be

implemented solely without being combined with other elements or features. Also,

it is also possible to construct the embodiments of the present disclosure by

combining a portion of the elements and/or features. A portion of a structure or

feature of an embodiment may be included in another embodiment or may be

replaced with the corresponding structure of feature of another embodiment. It

should be clearly understood that the claims which are not explicitly cited within the

technical scope of the present disclosure may be combined to form an embodiment

or may be included in a new claim by an amendment after application.

[823] The embodiments of the present disclosure may be implemented by

various means such as hardware, firmware, software, or a combination thereof. In

the case of hardware implementation, one embodiment of the present disclosure

may be implemented by using one or more of ASICs (Application Specific Integrated

Circuits), DPSs (Digital Signal Processors), DSPDs (Digital Signal Processing

Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate

Arrays), processors, controllers, micro-controllers, and micro-processors.

[824] In the case of implementation by firmware or software, one

embodiment of the present disclosure may be implemented in the form of modules,

procedures, functions, and the like which perform the functions or operations

described above. Software codes may be stored in the memory and activated by

the processor. The memory may be located inside or outside of the processor and

may exchange data with the processor by using various well-known means.

[825] It is apparent for those skilled in the art that the present disclosure

may be embodied in other specific forms without departing from the essential

characteristics of the present disclosure. Therefore, the detailed descriptions above

should be regarded as being illustrative rather than restrictive in every aspect. The

scope of the present invention should be determined by construction of the

appended claims, and all of the modifications that fall within an equivalent scope of

the present disclosure belong to the scope of the present invention.

[826] This document discloses a method for reporting CSI in a wireless

communication system with examples based on the 3GPP LTE/LTE-A system and

the 5G system (New RAT system); however, the present disclosure may be applied

to various other types of wireless communication systems in addition to the 3GPP

LTE/LTE-A system and the 5G system.

[827] Throughout this specification and the claims which follow, unless the context

requires otherwise, the word "comprise", and variations such as "comprises" and

"comprising", will be understood to imply the inclusion of a stated integer or step or

group of integers or steps but not the exclusion of any other integer or step or group

of integers or steps.

[828] The reference in this specification to any prior publication (or information

derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims (18)

1. [THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:]

   [Claim 1]

   A method of reporting, by a user equipment (UE), channel state information

   (CSI) in a wireless communication system, the method comprising:

   receiving, by the UE and from a base station (BS), downlink control

   information (DCI) related to an aperiodic CSI report that is to be performed by the UE

   in a slot n;

   determining, by the UE, a value ncQ,_ref based on a number of symbols Z'

   related to a time for computing the CSI;

   o determining, by the UE, a CSI reference resource as being a slot n - ncQi-ref

   in a time domain that is to be used for the aperiodic CSI report; and

   transmitting, by the UE and to the BS, the aperiodic CSI report in the slot n,

   based on the CSI reference resource being slot n - ncQi-ref,

   wherein the value ncQi-ref is a smallest value greater than or equal to

   msuchthattheslotfn- ncQref satisfies a valid downlink slot criteria, and

   wherein[ Jis a floor function and Nslma is a number of symbols in one slot.
2. [Claim 2]

   The method of claim 1, wherein the valid downlink slot criteria is based at

   least on (i) the number of symbols Z' related to the time for computing the CSI and

   (ii) a DCI processing time.
3. [Claim 3]

   The method of claim 1, wherein Nsymb is equal to 14 symbols in a slot.
4. [Claim 4]

   The method of claim 1, further comprising:

   receiving, from the BS, an aperiodic reference signal (CSI-RS) in the CSI

   reference resource, slot n - ncQi-ref

   determining the CSI based on the aperiodic CSI-RS; and generating the aperiodic CSI report based on the CSI.
5. [Claim 5]

   The method of claim 1, further comprising: determining the number of symbols Z' related to the time for computing the o CSI based on a CSI complexity and a subcarrier spacing.
6. [Claim 6]

   The method of claim 5, wherein the number of symbols Z' does not include a DCI processing time.
7. [Claim 7]

   The method of claim 1, wherein determining the value ncQi-ref based on the

   number of symbols Z' related to the time for computing the CSI comprises: determining the value ncQI-ref based on the number of symbols Z' related to

   the time for computing the CSI, and further based on a number of symbols in one slot.
8. [Claim 8]

   The method of claim 1, wherein receiving the DCI comprises: receiving the DCI in a slot other than the slot n in which the aperiodic CSI report is to be performed.
9. [Claim 9]

   The method of claim 1, wherein, based on the value ncQ,_ref being equal to

   zero, the aperiodic CSI report is performed in a same slot as receiving the DCI.
10. [Claim 10]

    A user equipment (UE) configured to report channel state information (CSI) in

    a wireless communication system, the UE comprising:

    a radio frequency (RF) module configured to transmit and receive radio

    signals;

    at least one processor; and

    at least one computer memory operably connectable to the at least one

    processor and storing instructions that, when executed, cause the at least one

    processor to perform operations comprising:

    receiving, via the RF module and from a base station (BS), downlink control

    information (DCI) related to an aperiodic CSI report that is to be performed by the UE

    in a slot n;

    determining, by the UE, a value ncQ,_ref based on a number of symbols Z'

    related to a time for computing the CSI;

    determining, by the UE, a CSI reference resource as being a slot n - ncQi-ref

    in a time domain that is to be used for the aperiodic CSI report; and

    transmitting, via the RF module and to the BS, the aperiodic CSI report in the

    slot n, based on the CSI reference resource being slot n - ncQi-ref,

    wherein the value ncQi-ref is a smallest value greater than or equal to

    Z'/N 1 ma]such thattheslotfn- ncQref satisfies a valid downlink slot criteria, and

    wherein[ Jis a floor function and Nslma is a number of symbols in one slot.
11. [Claim 11]

    The UE of claim 10, wherein the valid downlink slot criteria is based at least on (i) the number of symbols Z' related to the time for computing the CSI and (ii) a DCI processing time.
12. [Claim 12]

    The UE of claim 10, wherein Nsyjb is equal to 14 symbols in a slot.
13. [Claim 13]

    The UE of claim 10, wherein the operations further comprise: receiving, via the RF module and from the BS, an aperiodic reference signal (CSI-RS) in the CSI reference resource, slot n - ncQi-ref;

    determining the CSI based on the aperiodic CSI-RS; and generating the aperiodic CSI report based on the CSI.
14. [Claim 14]

    The UE of claim 10, wherein determining the number of symbols Z' related to the time for computing the CSI comprises: determining the number of symbols Z' related to the time for computing the CSI based on a CSI complexity and a subcarrier spacing.
15. [Claim 15]

    The UE of claim 14, wherein the number of symbols Z' does not include a DCI processing time.
16. [Claim 16]

    The UE of claim 10, wherein determining the value ncQi-ref based on the

    number of symbols Z' related to the time for computing the CSI comprises: determining the value ncQI-ref based on the number of symbols Z' and further based on information related to a subcarrier spacing.
17. [Claim 17]

    The UE of claim 10, wherein receiving the DCI comprises:

    receiving the DCI in a slot other than the slot n in which the aperiodic CSI

    report is to be performed.
18. [Claim 18]

    The UE of claim 10, wherein, based on the value ncQI-ref being equal to zero,

    the aperiodic CSI report is performed in a same slot as receiving the DCI.

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