HK40011785A

HK40011785A - Method for transmitting uplink data in wireless communication system and apparatus therefor

Info

Publication number: HK40011785A
Application number: HK62020001335.2A
Authority: HK
Inventors: Park Haewook; Park Jonghyun; Kim Kijun; Kang Jiwon; Kim Hyungtae
Original assignee: Lg 电子株式会社
Priority date: 2017-03-31
Filing date: 2018-04-02
Publication date: 2020-07-17

Description

Method for transmitting uplink data in wireless communication system and apparatus therefor

Technical Field

The present invention relates to wireless communication, and more particularly, to a method for transmitting uplink data performed by a user equipment and an apparatus for performing/supporting the same.

Background

Mobile communication systems have been developed to provide voice services while ensuring user activities. However, the service coverage of the mobile communication system has been extended even to data services as well as voice services. Today, the explosive growth of services has resulted in resource shortages and user demands for high-speed services, requiring more advanced mobile communication systems.

Requirements of next generation mobile communication systems may include support of huge data traffic, significant increase in transfer rate per user, accommodation of significantly increased number of connected devices, very low end-to-end delay, and high energy efficiency. To this end, various technologies such as dual connectivity, massive Multiple Input Multiple Output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), support for ultra-wideband, and device networking are being investigated.

Disclosure of Invention

Technical problem

An object of the present invention is to provide a codebook-based UL data transmission operation method for a user equipment.

In addition, an object of the present invention is to re-propose various/effective codebooks based on the CP-OFDM waveform.

The technical objects achieved in the present invention are not limited to the above technical objects, and other technical objects not described herein will be apparent to those skilled in the art from the following description.

Technical scheme

According to an aspect of the present invention, a method for transmitting a codebook-based Physical Uplink Shared Channel (PUSCH) performed by a User Equipment (UE) in a wireless communication system may include: receiving Downlink Control Information (DCI) for Uplink (UL) transmission scheduling; and performing codebook-based PUSCH transmission based on precoding information included in the DCI, the codebook including, when the PUSCH is transmitted using four antenna ports: a first group including a non-coherent precoding matrix for selecting only one port of each layer; a second group comprising a partially coherent precoding matrix for selecting two ports in at least one layer; and a third group comprising a fully coherent encoding matrix for selecting all ports of each layer.

In addition, the non-coherent precoding matrix may be a matrix including one vector having a non-zero value in each column, the partially coherent precoding matrix may be a matrix including two vectors having non-zero values in at least one column, and the fully coherent interference coding matrix may be a matrix including only vectors having non-zero values.

Additionally, the codebook may be a codebook based on a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform.

In addition, the DCI may include a Transmitted Precoding Matrix Indicator (TPMI), which is information as an index of a precoding matrix of which precoding information is selected for PUSCH transmission.

In addition, the TPMI may be jointly encoded with a Rank Indicator (RI), which is information of a layer used in PUSCH transmission.

In addition, the TPMI may be indicated for each Sounding Reference Signal (SRS) resource configured to the UE, and wherein the RI is collectively indicated for the configured SRS resources.

In addition, the TPMI and RI may be indicated collectively for all SRS resources configured to the UE.

In addition, the TPMI and RI may be indicated for each SRS resource configured to the UE.

In addition, the size of a predefined DMRS field in DCI may be differently determined according to RI jointly encoded with TPMI to determine DMRS ports.

In addition, the method for transmitting PUSCH may further include receiving constraint information of the number of layers available in the PUSCH transmission.

In addition, the size of the field in which the TPMI and the RI are jointly encoded may be decided based on the constraint information of the number of layers.

In addition, the method for transmitting the PUSCH may further include: constraint information of precoding matrices available in a PUSCH transmission is received in a codebook.

In addition, the constraint information of the precoding matrix may indicate a precoding matrix available in PUSCH transmission in a group unit or an individual precoding matrix unit.

In addition, the size of the field in which the TPMI and RI are jointly encoded may be decided based on constraint information of the precoding matrix.

Also, according to another aspect of the present invention, a User Equipment (UE) for transmitting a codebook-based Physical Uplink Shared Channel (PUSCH) in a wireless communication system may include a Radio Frequency (RF) unit for transmitting and receiving a radio signal; and a processor for controlling the RF unit, the processor configured to perform: receiving Downlink Control Information (DCI) for Uplink (UL) transmission scheduling; and performing codebook-based PUSCH transmission based on precoding information included in the DCI, the codebook including, when the PUSCH is transmitted using four antenna ports: a first group including a non-coherent precoding matrix for selecting only one port of each layer; a second group comprising a partially coherent precoding matrix for selecting two ports in at least one layer; and a third group comprising a fully coherent encoding matrix for selecting all ports of each layer.

Effects of the invention

According to the present invention, there is an effect that a codebook-based UL data transmission operation can be effectively supported in a new wireless communication system

Further, according to the present invention, there is an effect of using a new UL codebook, which can be used to support various transmission operations (non-coherent transmission operation, partially coherent transmission operation, fully coherent transmission operation, etc.).

It will be appreciated by those skilled in the art that the effects that can be achieved by the present invention are not limited to those that have been particularly described above, and other advantages of the present invention will be more clearly understood from the following detailed description.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to assist in understanding the invention, provide embodiments of the invention, and explain technical features of the invention by way of the following description.

Fig. 1 illustrates a structure of a radio frame in a wireless communication system to which the present invention can be applied.

Fig. 2 is a diagram illustrating a resource grid for a downlink slot in a wireless communication system to which the present invention can be applied.

Fig. 3 illustrates a structure of a downlink subframe in a wireless communication system to which the present invention can be applied.

Fig. 4 illustrates a structure of an uplink subframe in a wireless communication system to which the present invention can be applied.

Fig. 5 shows a configuration of a known MIMO communication system.

Fig. 6 is a diagram illustrating channels from multiple transmit antennas to a single receive antenna.

Fig. 7 illustrates a 2D AAS having 64 antenna elements in a wireless communication system to which the present invention is applicable.

Fig. 8 illustrates a system in which an eNB or UE has a plurality of transmission/reception antennas capable of forming an AAS-based 3D beam in a wireless communication system to which the present invention is applicable.

Fig. 9 illustrates a 2D antenna system having cross polarization in a wireless communication system to which the present invention is applicable.

Fig. 10 illustrates a transceiver unit model in a wireless communication system to which the present invention is applicable.

Fig. 11 illustrates a sub-containing sub-frame structure to which the present invention can be applied.

Fig. 12 is a diagram schematically illustrating a hybrid beamforming structure in terms of a TXRU and a physical antenna.

Fig. 13 is a diagram schematically illustrating a beam scanning operation of a synchronization signal and system information in a DL transmission process.

Fig. 14 illustrates a panel antenna array to which the present invention may be applied.

Fig. 15 illustrates an exemplary UL data transmission procedure between a UE and a gNB, which can be applied to the present invention.

Fig. 16 is a diagram illustrating SB TPMI allocation according to an embodiment of the present invention.

Fig. 17 is a flowchart illustrating a PUSCH transmission operation of a UE according to an embodiment of the present invention.

Fig. 18 is a block diagram of a wireless communication device according to an embodiment of the present invention.

Fig. 19 is a diagram illustrating an example of an RF module of a wireless communication device to which the method proposed in the present disclosure can be applied.

Fig. 20 is a diagram illustrating another example of an RF module of a wireless communication device to which the method proposed in the present disclosure can be applied.

Detailed Description

Some embodiments of the invention are described in detail with reference to the accompanying drawings. The detailed description to be disclosed together with the accompanying drawings is intended to describe some embodiments of the present invention, and is not intended to describe a unique embodiment of the present invention. The following detailed description includes further details in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without such further details.

In some cases, in order to avoid obscuring the concepts of the present invention, known structures and devices may be omitted, or may be shown in block diagram format based on the core functionality of each structure and device.

In this specification, a base station has the meaning of a terminal node of a network through which the base station communicates directly with a device. In this document, a specific operation described as being performed by the base station may be performed by an upper node of the base station according to the situation. That is, it is apparent that, in a network composed of a plurality of network nodes including a base station, various operations performed for communication with a device may be performed by the base station or other network nodes other than the base station. The Base Station (BS) may be replaced by other terminology such as a fixed station, a node B, eNB (evolved node B), a Base Transceiver System (BTS) Access Point (AP), or a gNB (next generation node B). In addition, devices may be fixed or may have mobility, and may be replaced with other terms such as User Equipment (UE), Mobile Station (MS), User Terminal (UT), mobile subscriber station (MSs), Subscriber Station (SS), Advanced Mobile Station (AMS), Wireless Terminal (WT), Machine Type Communication (MTC) device, machine to machine (M2M) device, or device to device (D2D) device.

Hereinafter, Downlink (DL) means communication from the eNB to the UE, and Uplink (UL) means communication from the UE to the eNB. In DL, the transmitter may be part of an eNB and the receiver may be part of a UE. In the UL, the transmitter may be part of the UE and the receiver may be part of the eNB.

Specific terms used in the following description have been provided to aid in understanding the present invention, and the use of such specific terms may be modified into various forms without departing from the technical spirit of the present invention.

The following techniques may be used in various wireless access systems such as 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), and non-orthogonal multiple access (NOMA). CDMA may be implemented using radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. TDMA may be implemented using radio technologies such as global system for mobile communications (GSM)/General Packet Radio Service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented using radio technologies such as the Electrical and electronics Engineers IEEE 802.11(Wi-Fi), IEEE 802.16(WiMAX), IEEE 802-20, or evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). Third generation partnership project (3GPP) Long Term Evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved UMTS terrestrial radio access (E-UTRA) and employs OFDMA in the downlink and SC-FDMA in the uplink. LTE-advanced (LTE-AA) is an evolution of 3GPP LTE.

Embodiments of the present invention may be supported by a standard document disclosed in at least one of IEEE 802, 3GPP, and 3GPP2, i.e., a wireless access system. That is, steps or portions, which belong to embodiments of the present invention and are not described in order to clearly disclose the technical spirit of the present invention, may be supported by these documents. In addition, all terms disclosed in this document may be described by a standard document.

For more clear description, the 3GPP LTE/LTE-a is mainly described, but the technical features of the present invention are not limited thereto.

General system to which the invention can be applied

Fig. 1 illustrates a structure of a radio frame in a wireless communication system to which an embodiment of the present invention can be applied.

The 3GPP LTE/LTE-a supports a radio frame structure type 1, which may be applied to Frequency Division Duplexing (FDD), and a radio frame structure type 2, which may be applied to Time Division Duplexing (TDD).

The size of a radio frame in the time domain is represented as a multiple of a time unit of T _ s/(15000 × 2048). UL and DL transmissions comprise radio frames with a duration T _ f 307200T _ s 10 ms.

Fig. 1(a) illustrates a radio frame structure type 1. The type 1 radio frame may be applied to both full duplex FDD and half duplex FDD.

The radio frame includes 10 subframes. The radio frame consists of 20 slots of length 15360 × T _ s 0.5ms, and is given an index of 0 to 19 per slot. One subframe includes two consecutive slots in the time domain, and subframe i includes slot 2i and slot 2i + 1. The time required to transmit a subframe is referred to as a Transmission Time Interval (TTI). For example, the length of the subframe i may be 1ms, and the length of the slot may be 0.5 ms.

UL transmission and DL transmission of FDD are distinguished in the frequency domain. There is no restriction in full duplex FDD, and the UE may not transmit and receive simultaneously in half duplex FDD operation.

One slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain and includes a plurality of Resource Blocks (RBs) in a frequency domain. In 3GPP LTE, since OFDMA is used in downlink, an OFDM symbol is used to represent one symbol period. The OFDM symbol may be referred to as one SC-FDMA symbol or symbol period. The RB is a resource allocation unit and includes a plurality of consecutive subcarriers in one slot.

Fig. 1(b) shows a frame structure type 2.

A type 2 radio frame includes two half-frames each 153600 × T _ s-5 ms long. Each field includes 30720 × T _ s 5 subframes of length 1 ms.

In frame structure type 2 of the TDD system, an uplink-downlink configuration is a rule indicating whether to allocate (or reserve) uplink and downlink to all subframes.

Table 1 shows an uplink-downlink configuration.

[ Table 1]

Referring to table 1, in each subframe of a radio frame, "D" denotes a subframe for DL transmission, "U" denotes a subframe for UL transmission, and "S" denotes a special subframe including three types of fields of a downlink pilot time slot (DwPTS), a Guard Period (GP), and an uplink pilot time slot (UpPTS).

The DwPTS is used for initial cell search, synchronization, or channel estimation in the UE. UpPTS is used for channel estimation in eNB and for UL transmission synchronization of the synchronized UE. The GP is a duration for removing interference occurring in the UL due to a multipath delay of a DL signal between the UL and the DL.

Each subframe i includes slot 2i and slot 2i +1 of T _ slot 15360 × T _ s 0.5 ms.

The UL-DL configuration may be classified into 7 types, and the positions and/or the numbers of DL subframes, special subframes, and UL subframes are different for each configuration.

Table 2 shows the configuration of the special subframe (length of DwPTS/GP/UpPTS).

[ Table 2]

The structure of the radio frame according to the example of fig. 1 is only one example, and the number of subcarriers included in the radio frame, the number of slots included in the subframe, and the number of OFDM symbols included in the slots may be variously changed.

Fig. 2 is a diagram illustrating a resource grid of one downlink slot in a wireless communication system to which an embodiment of the present invention may be applied.

Referring to fig. 2, one downlink slot includes a plurality of OFDM symbols in the time domain. It is described herein that one downlink slot includes 7 OFDM symbols and one resource block includes 12 subcarriers in the frequency domain for exemplary purposes only, and the present invention is not limited thereto.

Each element on the resource grid is referred to as a resource element, and one resource block includes 12 × 7 resource elements. Number N of resource blocks included in a downlink slot^DLDepending on the downlink transmission bandwidth.

The structure of the uplink slot may be the same as that of the downlink slot.

Fig. 3 illustrates a structure of a downlink subframe in a wireless communication system to which an embodiment of the present invention may be applied.

Referring to fig. 3, a maximum of three OFDM symbols located in a front portion of a first slot of a subframe correspond to a control region in which a control channel is allocated, and the remaining OFDM symbols correspond to a data region in which a Physical Downlink Shared Channel (PDSCH) is allocated. Downlink control channels used in 3GPP LTE include, for example, a Physical Control Format Indicator Channel (PCFICH), a Physical Downlink Control Channel (PDCCH), and a physical hybrid ARQ indicator channel (PHICH).

The PCFICH is transmitted in the first OFDM symbol of the subframe and carries information on the number of OFDM symbols used to transmit the control channel in the subframe (i.e., the size of the control region). The PHICH is a response channel for uplink and carries an Acknowledgement (ACK)/negative-acknowledgement (NACK) signal for hybrid automatic repeat request (HARQ). Control information transmitted in the PDCCH is referred to as Downlink Control Information (DCI). The DCI includes uplink resource allocation information, downlink resource allocation information, or an uplink transmit (Tx) power control command for a specific UE group.

Fig. 4 illustrates a structure of an uplink subframe in a wireless communication system to which an embodiment of the present invention may be applied.

Referring to fig. 4, an uplink subframe may be divided into a control region and a data region in a frequency domain. A Physical Uplink Control Channel (PUCCH) carrying uplink control information is allocated to the control region. A Physical Uplink Shared Channel (PUSCH) carrying user data is allocated to the data region. In order to maintain the single carrier characteristic, one UE does not transmit PUCCH and PUSCH at the same time.

A pair of Resource Blocks (RBs) is allocated to a PUCCH for one UE within a subframe. RBs belonging to the RB pair occupy different subcarriers in each of the two slots. This is called that the RB pair allocated to the PUCCH hops at the slot boundary.

Multiple Input Multiple Output (MIMO) MIMO (multiple input multiple output)

The MIMO technology does not use a single transmit antenna and a single receive antenna, which have been generally used so far, but uses a plurality of transmit (Tx) antennas and a plurality of receive (Rx) antennas. In other words, the MIMO technology is a technology for improving capacity or enhancing performance using multiple input/output antennas in a transmitting end or a receiving end of a wireless communication system. Hereinafter, MIMO is referred to as "multiple input/output antenna".

More specifically, the multiple input/output antenna technique does not rely on a single antenna path in order to receive a single overall message, but rather accomplishes the overall data by collecting multiple data blocks received via several antennas. Therefore, the multiple input/output antenna technology can increase a data transfer rate within a specific system range, and can also increase the system range by the specific data transfer rate.

It is expected that efficient multiple input/output antenna technology will be used because the next generation mobile communication requires a higher data transfer rate than that of the existing mobile communication. Under such circumstances, the MIMO communication technology is a next-generation mobile communication technology that can be widely used in mobile communication UEs and relay nodes, and has attracted public attention as a technology that can overcome the limitation of the transmission rate of another mobile communication caused by the expansion of data communication.

Meanwhile, multiple input/output antenna (MIMO) technology, which is a variety of transmission efficiency improvement techniques, is being developed, has attracted attention as a method capable of significantly improving communication capacity and transmission/reception performance even without additional allocation of frequencies or power increase.

Fig. 5 shows a configuration of a known MIMO communication system.

Referring to fig. 5, if the number of transmit (Tx) antennas is increased to N _ T and the number of receive (Rx) antennas is simultaneously increased to N _ R, a theoretical channel transmission capacity is increased in proportion to the number of antennas, unlike the case where a plurality of antennas are used only in a transmitter or a receiver. Therefore, the transmission rate can be increased, and the frequency efficiency can be significantly improved. In this case, the transmission rate according to the increase of the channel transmission capacity can theoretically increase a value obtained by multiplying the following rate increment R _ i by the maximum transmission rate R _ o if one antenna is used.

[ equation 1]

R_i＝min(N_T,N_R)

That is, for example, in a MIMO communication system using 4 transmission antennas and 4 reception antennas, a transmission rate four times as high as that of a single antenna system can be theoretically obtained.

Such multiple input/output antenna technology can be divided into a spatial diversity method for increasing transmission reliability using symbols passing through various channel paths and a spatial multiplexing method for increasing a transmission rate by simultaneously transmitting a plurality of data symbols using a plurality of transmit antennas. Further, active research is recently being conducted on a method of appropriately obtaining the advantages of both methods by combining the two methods.

Each of the methods will be described in more detail below.

First, the spatial diversity method includes a space-time block code series method and a space-time tresis code series method using both diversity gain and coding gain. Generally, the tress code series method is better in terms of bit error rate improvement performance and code generation freedom, while the space-time block code series method has low computational complexity. Such a spatial diversity gain may correspond to an amount corresponding to a product (N _ T × N _ R) of the number of transmit antennas (N _ T) and the number of receive antennas (N _ R).

Second, the spatial multiplexing scheme is a method of transmitting different data streams in the transmit antennas. In this case, in the receiver, mutual interference is generated between data simultaneously transmitted by the transmitter. The receiver removes interference using an appropriate signal processing scheme and receives the data. The noise removal method used in this case may include a Maximum Likelihood Detection (MLD) receiver, a Zero Forcing (ZF) receiver, a Minimum Mean Square Error (MMSE) receiver, a diagonal bell labs layered space-time code (D-BLAST), and a vertical bell labs layered space-time code (V-BLAST). In particular, if the transmitting end can know channel information, a Singular Value Decomposition (SVD) method may be used.

Third, there is a method using a combination of spatial diversity and spatial multiplexing. If only the spatial diversity gain is to be obtained, the performance improvement gain according to the increase of the diversity difference gradually saturates. If only the spatial multiplexing gain is used, transmission reliability in a radio channel is deteriorated. Methods of solving this problem and obtaining two gains have been studied and may include a double space-time transmit diversity (double STTD) method and a space-time bit interleaved coded modulation (STBICM).

To describe the communication method in the multiple input/output antenna system, as described above, the communication method may be represented as follows via mathematical modeling in more detail.

First, as shown in fig. 5, it is assumed that there are N _ T transmit antennas and N _ R receive antennas.

First, a transmission signal is described below. If there are N _ T transmit antennas as described above, the largest entry of information that can be sent is N _ T, which can be represented using the following vector.

[ equation 2]

Meanwhile, the transmission power may be different in each of the transmission information s _1, s _ 2. In this case, if the respective transmission powers are P _1, P _2,. and P _ NT, transmission information with controlled transmission power may be represented using the following vector.

[ equation 3]

Further, the transmission information with controlled transmission power in equation 3 may be represented as follows using a diagonal matrix P of transmission power.

[ equation 4]

Meanwhile, the information vector having the controlled transmission power is multiplied by the weighting matrix W in equation 4, thereby forming N _ T transmission signals x _1, x _2,.. and x _ NT actually transmitted. In this case, the weighting matrix is used to appropriately distribute transmission information to the antennas according to the transmission channel conditions. The following equations may be represented using the transmission signals x _1, x _2,. and x _ NT.

[ equation 5]

In this case, W _ ij represents a weight between the ith transmission antenna and the jth transmission information, and W is an expression of a matrix of weights. Such a matrix W is called a weighting matrix or a precoding matrix.

Meanwhile, a transmission signal x such as described above may be considered for use in a case where spatial diversity is used and in a case where spatial multiplexing is used.

If spatial multiplexing is used, all elements of the information vector s have different values because different signals are multiplexed and transmitted. In contrast, if spatial diversity is used, elements of all information vectors s have the same value because the same signal is transmitted through several channel paths.

A method of mixing spatial multiplexing and spatial diversity may be considered. In other words, for example, the same signal may be transmitted using spatial diversity through 3 transmission antennas, and the remaining different signals may be spatially multiplexed and transmitted.

If there are N _ R receive antennas, the receive signals y _1, y _2, ·, y _ NR of the respective antennas are represented as follows using a vector y.

[ equation 6]

Meanwhile, if channels in a multiple input/output antenna communication system are modeled, the channels may be classified according to transmit/receive antenna indexes. The channel from transmit antenna j through receive antenna i is denoted h _ ij. In this case, it is to be noted that the index of the receiving antenna first appears and the index of the transmitting antenna subsequently appears in the order of the index of h _ ij.

Several channels may be grouped and represented in vector and matrix form. For example, vector expressions are described below.

As shown in fig. 6, channels from a total of N _ T transmit antennas to a receive antenna i may be represented as follows.

[ equation 7]

Further, if all channels from N _ T transmit antennas to N _ R receive antennas are represented by a matrix, such as equation 7, they may be represented as follows.

[ equation 8]

Meanwhile, after the actual channel is subjected to the channel matrix H, Additive White Gaussian Noise (AWGN) is added to the actual channel. Therefore, AWGN N _1, N _2, · N _ NR added to the N _ R receiving antennas, respectively, are represented as follows using vectors.

[ equation 9]

The transmission signal, the reception signal, the channel, and the AWGN in the multiple input/output antenna communication system may be represented by modeling such as the transmission signal, the reception signal, the channel, and the AWGN as described above as having the following relationships.

[ equation 10]

Meanwhile, the number of rows and columns of the channel matrix H indicating the state of the channel is determined by the number of transmission/reception antennas. In the channel matrix H, as described above, the number of rows becomes equal to the number of reception antennas N _ R, and the number of columns becomes equal to the number of transmission antennas N _ T. That is, the channel matrix H becomes an N _ R × N _ T matrix.

In general, the rank of a matrix is defined as the minimum number of independent rows or columns. Thus, the rank of the matrix is not greater than the number of rows or columns. In terms of expression, for example, the rank of the channel matrix H is limited as follows.

[ equation 11]

rank(H)≤min(N_T,N_R)

Further, if the matrix undergoes eigenvalue decomposition, the rank may be defined as the number of eigenvalues, which belong to the eigenvalues and are not 0. Likewise, if a rank is subjected to Singular Value Decomposition (SVD), it may be defined as the number of singular values other than 0. Thus, the physical meaning of rank in a channel matrix can be said to be the maximum number of different information that can be sent in a given channel.

In this specification, a "rank" for MIMO transmission indicates the number of paths through which signals can be independently transmitted on a specific frequency resource at a specific time point. The "number of layers" indicates the number of signal streams transmitted through each path. Generally, unless otherwise described, a rank has the same meaning as the number of layers, because a transmitting end transmits the number of layers corresponding to the number of ranks used in signal transmission.

Reference Signal (RS)

In a wireless communication system, since data is transmitted through a radio channel, a signal may be distorted during transmission. In order for the receiving end to accurately receive the distorted signal, it is necessary to correct the distortion of the received signal using the channel information. In order to detect channel information, a method of detecting channel information using a distortion degree of a signal transmission method and a signal known to both a transmitting side and a receiving side when transmitting the signal known to both the transmitting side and the receiving side through a channel is mainly used. The aforementioned signals are referred to as pilot signals or Reference Signals (RSs).

Further, recently, when most mobile communication systems transmit packets, they use a method capable of improving efficiency of transmitting/receiving data by employing a plurality of transmitting antennas and a plurality of receiving antennas instead of using one transmitting antenna and one receiving antenna used so far. When a plurality of input/output antennas are used to transmit and receive data, it is necessary to detect a channel state between a transmission antenna and a reception antenna in order to accurately receive a signal. Therefore, each transmit antenna must have a separate reference signal.

In a mobile communication system, RSs can be basically divided into two types according to their purposes. There are an RS having a purpose of obtaining channel state information and an RS for data demodulation. The former has the purpose of obtaining channel state information in the downlink by the UE. Therefore, the corresponding RS must be transmitted in a wideband, and the UE must be able to receive and measure the RS, although the UE does not receive downlink data in a specific subframe. In addition, the former is also used for Radio Resource Management (RRM) measurements, such as handovers. The latter is an RS transmitted together with corresponding resources when the eNB transmits downlink. The UE may perform channel estimation by receiving the corresponding RS and thus may demodulate data. The corresponding RS must be transmitted in the region where data is transmitted.

The downlink RS includes one common RS (crs) for acquisition and measurement of information on a channel state, such as handover, shared by all UEs within a cell and a dedicated RS (drs) for data demodulation only for a specific UE. Such RSs can be used to provide information for demodulation and channel measurement. That is, the DRS is used only for data demodulation, and the CRS is used for both purposes of channel information acquisition and data demodulation.

The receiving side (i.e., UE) measures a channel state based on the CRS, and feeds back an indicator related to channel quality, such as a Channel Quality Indicator (CQI), a Precoding Matrix Index (PMI), and/or a Rank Indicator (RI), to the transmitting side (i.e., eNB). CRS is also referred to as cell-specific RS. In contrast, a reference signal related to feedback of Channel State Information (CSI) may be defined as a CSI-RS.

The DRS may be transmitted through a resource element if demodulation of data on the PDSCH is required. The UE may receive information on whether there is a DRS through a higher layer, and the DRS is valid only when a corresponding PDSCH has been mapped. The DRS may also be referred to as UE-specific RS or demodulation RS (dmrs).

CSI-RS configuration

In the current LTE standard, parameters for CSI-RS configuration include antennaPortsCount, subframeConfig, resourceConfig, and the like. These parameters indicate the number of antenna ports through which the CSI-RS is transmitted, the periodicity and offset of a subframe in which the CSI-RS is to be transmitted, the positions (i.e., frequency and OFDM symbol index) of Resource Elements (REs) in which the CSI-RS is transmitted in the corresponding subframe, and the like. Specifically, the eNB forwards the parameters/information of the following when indicating/forwarding a specific CSI-RS configuration to the UE.

-antennaPortsCount: parameters representing the number of antenna ports used to transmit CSI reference signals (e.g., 1 CSI-RS port, 2 CSI-RS ports, 4 CSI-RS ports, or 8 CSI-RS ports)

-resourceConfig: parameters related to CSI-RS allocated resource location

-subframeConfig: parameters related to a period and offset of a subframe in which a CSI-RS is to be transmitted

-p-c: with respect to the UE assumption for reference PDSCH transmit power for CSI feedback CSI-RS, Pc is the assumed ratio of PDSCH EPRE to CSI-RS EPRE when the UE derives CSI feedback and takes a value in the range of [ -8,15 ] with a step size of 1 dB.

-zeroTxPowerResourceConfigList: parameters related to zero-power CSI-RS

-zeroTxPowerSubframeConfig: parameters related to a period and offset of a subframe in which a zero-power CSI-RS is to be transmitted

Massive MIMO

A MIMO system having a plurality of antennas may be referred to as a massive MIMO system, and is spotlighted as a means for improving spectral efficiency, energy efficiency, and processing complexity.

Recently, massive MIMO systems have been discussed in order to meet the requirements of spectrum efficiency of future mobile communication systems in 3 GPP. Massive MIMO is also known as full-dimensional MIMO (FD-MIMO).

LTE release 12 and subsequent wireless communication systems consider the introduction of Active Antenna Systems (AAS).

Unlike conventional passive antenna systems in which an amplifier capable of adjusting the phase and amplitude of a signal is separated from an antenna, the AAS is configured in such a manner that each antenna includes an active element such as an amplifier.

The AAS does not require additional cables, connectors, and hardware for connecting the amplifier and the antenna, and thus has high energy efficiency and low operating cost. In particular, the AAS supports electronic beam steering of each antenna, and thus can implement enhanced MIMO in consideration of a beam direction and a beam width or a 3D beam pattern to form an accurate beam pattern.

With the introduction of enhanced antenna systems such as AAS, massive MIMO with multiple input/output antennas and multi-dimensional antenna structures is also considered. For example, when forming a 2D antenna array instead of a conventional linear antenna array, a 3D beam pattern can be formed using the active antennas of the AAS.

Fig. 7 illustrates a general 2D antenna array. A case may be considered in which Nt ═ Nv · Nh antennas are arranged in a square, as shown in fig. 7. Here, Nh indicates the number of antenna columns in the horizontal direction, and Nv indicates the number of antenna rows in the vertical direction.

When the above-described 2D antenna array is used, radio waves can be controlled in both the vertical direction (elevation angle) and the horizontal direction (azimuth angle) to control a transmission beam in a 3D space. This wavelength control mechanism may be referred to as 3D beamforming.

Fig. 8 illustrates the above example and illustrates a 3D MIMO system using a 2D antenna array (i.e., 2D-AAS).

From the perspective of the transmit antenna, when a 3D beam pattern is used, quasi-static or dynamic beamforming can be performed in the vertical direction as well as in the horizontal direction of the beam. For example, an application such as sector formation in the vertical direction may be considered.

From the perspective of the receiving antenna, when a reception beam is formed using a large-scale receiving antenna, a signal power increasing effect according to the antenna array gain can be expected. Therefore, in case of uplink, the eNB can receive signals transmitted from the UE through a plurality of antennas, and the UE can set its transmission power to a very low level in consideration of the gain of a large-scale reception antenna.

A 2D planar antenna array model taking polarization into account can be patterned as shown in fig. 9.

Unlike conventional MIMO systems using passive antennas, active antenna-based systems are able to dynamically control the gain of the antenna elements by applying weights to active elements (e.g., amplifiers) attached to (or included in) each antenna element. Because the radiation pattern depends on the antenna arrangement, such as the number of antenna elements and the antenna spacing, the antenna system can be modeled at the antenna element level.

The antenna arrangement model as shown in fig. 9 may be represented by (M, N, P) corresponding to parameters characterizing the antenna arrangement structure.

M indicates the number of antenna elements having the same polarization in each column (i.e., in the vertical direction) (i.e., the number of antenna elements having a +45 ° tilt in each column or the number of antenna elements having a-45 ° tilt in each column).

N indicates the number of columns in the horizontal direction (i.e., the number of antenna elements in the horizontal direction).

P indicates the dimension of the polarization. In the case of cross polarization as shown in fig. 8, P is 2. In the case of co-polarization, P ═ 1.

The antenna ports may be mapped to physical antenna elements. The antenna ports may be defined by reference signals associated therewith. For example, antenna port 0 may be associated with a cell-specific reference signal (CRS), and antenna port 6 may be associated with a Positioning Reference Signal (PRS) in an LTE system.

For example, the antenna ports and physical antenna elements may be mapped one-to-one. This may correspond to the case where a single cross-polarized antenna element is used for downlink MIMO or downlink transmit diversity. For example, antenna port 0 may be mapped to a single physical antenna element, while antenna port 1 may be mapped to another physical antenna element. In this case, there are two downlink transmissions for the UE. One associated with the reference signal of antenna port 0 and the other associated with the reference signal of antenna port 1.

Alternatively, a single antenna port may be mapped to multiple physical antenna elements. This may correspond to the case where a single antenna port is used for beamforming. Beamforming enables downlink transmissions to be directed to a particular UE by using multiple physical antenna elements. This can typically be achieved using an antenna array consisting of multiple columns of multiple cross-polarized antenna elements. In this case, there is a single downlink transmission derived from a single antenna port with respect to the UE. One associated with CRS of antenna port 0 and the other associated with CRS of antenna port 1.

That is, the antenna port represents downlink transmission on the part of the UE, rather than substantial downlink transmission from a physical antenna element in the eNB.

Alternatively, multiple antenna ports may be used for downlink transmission, and each antenna port may be multiple physical antenna ports. This may correspond to the case where the antenna arrangement is used for downlink MIMO or downlink diversity. For example, antenna port 0 may be mapped to multiple physical antenna ports, and antenna port 1 may be mapped to multiple physical antenna ports. In this case, there are two downlink transmissions for the UE. One associated with the reference signal of antenna port 0 and the other associated with the reference signal of antenna port 1.

In FD-MIMO, MIMO precoding of data streams may be subject to antenna port virtualization, transceiver unit (TXRU) virtualization, and antenna element patterns.

In antenna port virtualization, the streams on the antenna ports are precoded on the TXRU. In TXRU virtualization, TXRU signals are precoded across antenna elements. In the antenna element pattern, a signal radiated from the antenna element may have a directional gain pattern.

In conventional transceiver modeling, a static one-to-one mapping between antenna ports and TXRUs is assumed, and TXRU virtualization effects are integrated into a (TXRU) antenna pattern that includes both TXRU virtualization and effects of antenna element patterns.

Antenna port virtualization may be performed by a frequency selective method. In LTE, antenna ports are defined along with reference signals (or pilots). For example, to transmit data precoded on antenna ports, DMRS is transmitted in the same bandwidth as a data signal, and the DMRS and the data signal are precoded by the same precoder (or the same TXRU virtualized precoding). For CSI measurement, CSI-RS is transmitted through multiple antenna ports. In CSI-RS transmission, precoders characterizing the mapping between CSI-RS ports and TXRUs may be designed as eigenmatrices, enabling the UE to estimate TXRU virtualized precoding matrices for data precoding vectors.

The 1D TXRU virtualization and the 2D TXRU virtualization are discussed as TXRU virtualization methods, which will be described below with reference to the drawings.

In 1D TXRU virtualization, M _ TXRU is associated with M antenna elements in a single column antenna arrangement with the same polarization.

In the 2D TXRU virtualization, a TXRU model corresponding to the antenna arrangement model (M, N, P) of fig. 8 may be represented by (M _ TXRU, N, P). Here, M _ TXRU denotes the number of 2D TXRUs in the same column and existing in the same polarization, and there is always M _ TXRU ≦ M. That is, the total number of TXRUs is M _ TXRU × N × P.

Depending on the correlation between the antenna element and the TXRU, the TXRU virtualization model may be divided into TXRU virtualization model option-1: subarray partition model and TXRU virtualization model option-2 as shown in fig. 10 (a): a fully connected model as shown in fig. 10 (b).

Referring to fig. 10(a), in case of the sub-array partition model, an antenna element is divided into a plurality of antenna element groups, and each TXRU is connected to one of the groups.

Referring to fig. 10(b), in case of a full connection model, a plurality of TXRU signals are combined and delivered to a single antenna element (or antenna element array).

In fig. 10, q is the transmit signal vector for the M co-polarized antenna elements in a single column, W is the wideband TXRU virtualization weight vector, W is the wideband TXRU virtualization weight matrix, and x is the signal vector for the M _ TXRU TXRUs.

Here, the mapping between the antenna ports and the TXRU may be 1-to-1 or 1-to-many mapping.

Fig. 10 illustrates an example of TXRU to antenna element mapping, and the invention is not limited thereto. The invention is equally applicable to mapping between TXRU and antenna elements implemented in various ways in terms of hardware.

Channel State Information (CSI) -reference signal (CSI)-RS) definition

With respect to the serving cell and the UE configured with transmission mode 9, the UE may be configured with one CSI-RS resource configuration. With respect to serving cells and UEs configured with transmission mode 10, the UE may be configured with one or more CSI-RS resource configurations. The UE assumes that the following parameters for non-zero transmission power of CSI-RS are configured by higher layer signaling for each CSI-RS resource configuration:

CSI-RS resource configuration identity (when UE is configured with transmission mode 10)

-number of CSI-RS ports

-CSI-RS configuration

-CSI-RS subframe configuration (I)_CSI-RS)

-reference PDSCH transmission power P for CSI feedback_cUE hypothesis (when UE is configured with transmission mode 9)

Reference PDSCH transmission power P for CSI feedback per CSI process when the UE is configured with transmission mode 10_cThe UE of (2) assumes. In a CSI subframe set C for a single CSI process_CSI,0And C_CSI,1Configured by higher layer signaling, P is configured for each CSI subframe set of a respective CSI process_c。

-pseudo-random sequence generator parameters (n)_ID)

-CDM Type parameters when the UE is configured with higher layer parameters CSI-Reporting-Type and CSI-Reporting-Type is set for "Type a" of CSI process.

Higher layer parameters QCL-CRS-Info-r11CRS, QCL class B UE hypothesis with CRS antenna port and CSI-RS antenna port with the following parameters when UE is configured with transmission mode 10:

-qcl-ScramblingIdentity-r11。

-crs-PortsCount-r11。

-mbsfn-SubframeConfigList-r11。

P_cis the assumed ratio of PDSCH EPRE to CSI-RS EPRE when the UE derives CSI feedback, and employs [ -8,15 with 1dB step size]Values in the dB range. Here, PDSCH EPRE corresponds to the number of symbols PDSCH EPRE relative to the ratio of cell-specific RS EPREs.

The UE does not desire to configure the CSI-RS and the PMCH in the same subframe of the serving cell.

For frame structure type 2 serving cells and 4 CRS ports, the UE does not expect to receive CSI-RS configuration indices belonging to the set [20-31] in the case of normal CP or the set [16-27] in the case of extended CP.

The UE may assume that the CSI-RS antenna ports of the CSI-RS resource configuration are at QCL for delay spread, doppler shift, average gain, and average delay.

A UE configured with transmission mode 10 and QCL type B may assume that antenna ports 0 to 3 associated with QCL-CRS-Info-r11 corresponding to the CSI-RS resource configuration and antenna ports 15 to 22 corresponding to the CSI-RS resource configuration are at QCL for doppler shift and doppler spread.

A UE configured with transmission 10 and higher layer parameter CSI-Reporting-Type, the CSI-Reporting-Type being set to "class B" where the number of configured CSI resources for the CSI process configuration is one or more, and QCL Type B is set, the UE does not expect to receive CSI-RS resource configurations of CSI processes with different values of higher layer parameters QCL-CRS-Info-r 11.

Reference signal sequence in subframe constructed/configured for CSI-RS transmissionCan be mapped to complex-valued modulation symbolsWhich is used as a reference symbol for the antenna port p. This mapping depends on the higher layer parameter CDMType.

In the case where CDMType does not correspond to CDM4, mapping may be performed according to equation 12 below.

[ equation 12]

l"＝0,1

In the case where CDMType corresponds to CDM4, mapping may be performed according to equation 13 below.

[ equation 13]

l"＝0,1

k”＝0,1

i＝2k”+l”

W in equation 13_p'(i) As determined by table 6 below. Table 3 shows the sequence w of CDM4_p'(i)。

[ Table 3]

OFDM parameter set

As more and more communication devices require greater communication capacity, the necessity of mobile broadband communication that is more improved than existing Radio Access Technologies (RATs) has been raised. In addition, large-scale MTC (machine type communication) that provides various services by connecting a plurality of devices and objects anytime and anywhere is also one of important issues, which is considered in next-generation communication. Furthermore, the design of communication systems has been discussed, where the service and/or the UE are sensitive to reliability and delay. Therefore, introduction of next generation RAT has been discussed so far, which considers enhanced mobile broadband communication, large-scale MTC, ultra-reliable and low-delay communication (URLLC), etc., and such technology is generally referred to as "new RAT (nr)".

The new RAT system uses an OFDM transmission scheme or similar transmission scheme, typically the set of OFDM parameters shown in table 4 below.

[ Table 4]

Parameter(s)	Value of
		Subcarrier spacing (Δ f)	60kHz
OFDM symbol length	16.33μs
		Cyclic Prefix (CP) length	1.30μs/1.17μss
System bandwidth	80MHz
		Number of available subcarriers	1200
Sub-frame length	0.25ms
		Number of OFDM symbols per subframe	14 symbols

Self-contained subframe structure

In the TDD system, in order to minimize data transmission delay, a self-contained subframe structure in which a control channel and a data channel are TDM as shown in fig. 11 has been considered in a 5-generation new RAT.

Fig. 11 illustrates a self-contained subframe structure to which the present invention can be applied.

The shaded region in fig. 11 shows a transmission region of a physical channel PDCCH for forwarding DCI, and the dark region shows a transmission region of a physical channel PUCCH for forwarding Uplink Control Information (UCI).

The control information that the eNB forwards to the UE through the DCI includes information of cell configuration that the UE needs to know, DL specific information such as DL scheduling, and/or UL specific information such as UL grant. Also, the control information that the eNB forwards to the UE through the UCI includes an ACK/NACK report for HARQ of DL data, a CSI report and/or a Scheduling Request (SR) for DL channel state, and the like.

The regions not labeled in fig. 11 may be used for a transmission region of a physical channel PDSCH for Downlink (DL) data and a transmission region of a physical channel PUSCH for Uplink (UL) data. In a characteristic of this structure, DL transmission and UL transmission may be sequentially performed in a Subframe (SF), DL data may be transmitted, and UL ACK/NACK may be received in a corresponding SF. Therefore, according to this structure, when a data transmission error occurs, the time required to retransmit data is reduced, and thus, the delay until the final data forwarding can be minimized.

In such a self-contained subframe structure, a time interval is required for a process in which the eNB and the UE switch from a transmission mode to a reception mode or a process in which the eNB and the UE switch from a reception mode to a reception mode. For this, a part of OFDM symbols of timing for switching from DL to UL may be set as GP, and this subframe type may be referred to as "self-contained SF".

Analog beamforming

In a millimeter wave (mmW) band, a wavelength becomes short and a plurality of antenna elements can be mounted in the same region. That is, the wavelength in the 30GHz band is 1cm, and therefore, a two-dimensional arrangement shape of 64(8X8) antenna elements in total mounted in a 5 × 5cm panel at 0.5 λ (wavelength) intervals is available. Therefore, in the mmW band, a Beamforming (BF) gain is increased by using a plurality of antenna elements, and thus, a coverage is increased or throughput becomes higher.

In this case, each antenna element has a transceiver unit (TXRU) so that it can be used to adjust transmission power and phase, and independent beamforming can be used for each frequency resource. However, when the TXRU is installed in all of about 100 antenna elements, there is a problem in that the effectiveness in terms of cost is reduced. Therefore, a method has been considered to map a plurality of antenna elements in a single TXRU and adjust the direction of a beam by an analog phase shifter. Such analog beamforming techniques can produce only one beam direction in the entire frequency band and have the disadvantage that frequency selective beamforming is not available.

As an intermediate form between digital BF and analog BF, B hybrid BFs may be considered, which are smaller than Q antenna elements. In this case, the direction of beams that can be transmitted simultaneously is limited to less than B; even though it varies according to the connection scheme between the B TXRU and the Q antenna elements.

In addition, in the case of using multiple antennas in a new RAT system, a hybrid beamforming technique in which digital beamforming and analog beamforming are combined appears. In this case, analog beamforming (or Radio Frequency (RF) beamforming) means an operation of performing precoding (or combining) in the RF terminal. In the hybrid beamforming technique, each of the baseband terminal and the RF terminal performs precoding (or combining), and thus, there is an advantage in that performance close to digital beamforming can be obtained while reducing the number of RF chains and the number of digital (D)/analog (a) (or a/D) converters. For ease of description, the hybrid beamforming structure may be represented by N transceiver units (TXRU) and M physical antennas. Then, digital beamforming of the L data layers to be transmitted in the transmitter may be represented by an N × L matrix. Then, analog beamforming is applied, the transformed N digital signals are transformed into analog signals by TXRU, and then represented by an mxn matrix.

Fig. 12 is a diagram schematically illustrating a hybrid beamforming structure in terms of TXRU and physical antenna. Fig. 12 illustrates a case where the number of digital beams is L and the number of analog beams is N.

In new RAT systems, the direction has been considered: the design eNB may change analog beamforming in symbol units and support more efficient beamforming for UEs located in a particular area. Further, while the specific N TXRU and M RF antennas shown in fig. 12 are defined as a single antenna panel, in the new RAT system, a manner of introducing multiple antenna panels is also considered, to which independent hybrid beamforming may be applied.

In the case where the eNB uses a plurality of analog beams, the analog beams beneficial to receive signals may be changed according to each UE. Thus, having considered the beam scanning operation, for at least synchronization signals, system information, paging, etc., the plurality of analog beams to be applied by the eNB in a specific Subframe (SF) is changed for each symbol so that all UEs have reception variation.

The physical resource (or physical channel) transmitting the system information of the new RAT system in fig. 13 is called an x physical broadcast channel (xPBCH).

Referring to fig. 13, analog beams belonging to different antenna panels in a single symbol may be transmitted simultaneously. For measuring the channel of each analog beam, as shown in fig. 13, introduction of a beam RS (brs), which introduces a beam RS (brs), which is an RS to apply and transmit a single analog beam (corresponding to a specific antenna panel), has been discussed. A BRS may be defined for multiple antenna ports, and each antenna port of the BRS may correspond to a single analog beam. At this time, unlike the BRS, a synchronization signal or xPBCH may be transmitted, and all analog beams in the analog beam group may be applied so as to be well received by any UE.

RRM measurements in LTE

The LTE system supports RRM operations for power control, scheduling, cell search, cell study, handover, radio link or connection monitoring, connection establishment/re-establishment, etc. The serving cell may request RRM measurement information, which is a measurement value for performing RRM operation on the UE. Representatively, in the LTE system, the UE may measure/obtain and report information such as Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and the like. Specifically, in the LTE system, the UE receives "measConfig" from the serving cell as a higher layer signal for RRM measurement. The UE may measure RSRP or RSRQ according to the information of "measConfig". Here, RSRP, RSRQ, and RSSI according to the TS 36.214 document of the LTE system are defined as follows.

[RSRP]

The Reference Signal Received Power (RSRP) is defined as the linear average of the power contributions (in [ W ]) of the resource elements carrying the cell-specific rs (crs) within the considered measurement frequency bandwidth. For RSRP determination, TS 36.211[3] compliant CRS R0 will be used. In the case where the UE can reliably detect that R1 is available, R1 may be used in addition to R0 to determine RSRP.

The reference point for RSRP should be the antenna connector of the UE.

In case the UE is using receiver diversity, the reported value should not be lower than the respective RSRP of any respective diversity branch.

[RSRQ]

The Reference Signal Received Quality (RSRQ) is defined as the ratio NxRSRP/(E-UTRA carrier RSSI) (i.e., E-UTRA carrier RSSI vs. NxRSRP), where N is the number of RBs of the E-UTRA carrier RSSI measurement bandwidth. The measurements in the numerator and denominator should be made on the same set of resource blocks.

The E-UTRA carrier Received Signal Strength Indicator (RSSI) may comprise a linear average of the total received power (in [ W ]), channel interference, thermal noise, etc., observed by the UE over N resource blocks in the measurement bandwidth from all sources (including co-channel serving and non-serving cells) only in the OFDM symbol containing the reference symbol for antenna port 0. In the case where higher layer signaling indicates certain subframes for performing RSRQ measurements, the RSSI may be measured over all OFDM symbols in the indicated subframes.

The reference point for RSRQ should be the UE's antenna connector.

In case the UE is using receiver diversity, the reported value will not be lower than the respective RSRQ of any respective diversity branch.

[RSSI]

The RSSI may correspond to the received wideband power including thermal noise and noise generated in the receiver within the bandwidth defined by the receiver pulse shaping filter.

The reference point for the measurement will be the antenna connector of the UE.

In case the UE is using receiver diversity, the reported value will not be lower than the corresponding UTRA carrier RSSI of any of the separately received antenna branches.

According to the definition, a UE operating in the LTE system may be allowed to measure RSRP in a bandwidth corresponding to one of 6, 15, 25, 50, 75 and 100 RBs (resource blocks) through an Information Element (IE) related to a measurement bandwidth transmitted in a system information block type 3(SIB3) in case of intra-frequency measurement, and to measure RSRP in a bandwidth corresponding to one of 6, 15, 25, 50, 75 and 100 RBs (resource blocks) through an allowed measurement bandwidth transmitted in a system information block type 5(SIB5) in case of inter-frequency. Alternatively, in the absence of an IE, the UE may default to measurements in the band of the entire DL system. At this time, in case that the UE receives the allowed measurement bandwidth, the UE may regard the corresponding value as the maximum measurement bandwidth and may freely measure the RSRP value within the corresponding bandwidth/value. However, in order for the serving cell to transmit an IE defined as Wideband (WB) -RSRQ and configure the allowed measurement bandwidth as 50RB or more, the UE should calculate an RSRP value for the entire allowed measurement bandwidth. Meanwhile, the RSSI may be measured in a frequency band that a receiver of the UE has according to the definition of the RSSI bandwidth.

Referring to fig. 14, the panel antenna array includes Mg panels in a horizontal domain and Ng panels in a vertical domain, and one panel may include M columns and N rows. In particular, in this figure, a panel based on cross-polarized (X-pol) antennas is shown. Thus, the total number of antenna elements may be 2 × M × N × Mg × Ng.

Proposal of new codebook

In the following, a new codebook design for UL coding is proposed in an environment like a new RAT. In addition, UL codebook subset restriction is also proposed.

As shown in fig. 14, multi-panel functions are supported in the new RAT, but in the present disclosure, a codebook design is proposed by giving priority to a single panel for convenience of description.

The 2D discrete fourier transform beam may be defined as equation 14, which may be applied to a 2D antenna array in a single panel.

[ equation 14]

Here, m1 and m2 correspond to 1D-DFT codebook indices of the first and second domains, respectively. In addition, N1 and N2 correspond to the number of antenna ports for each polarization in the first and second dimensions, respectively, in the panel, and o1 and o2 correspond to the oversampling factors for the first and second dimensions, respectively, in the panel.

The codebook as presented in equation 14 follows a two-stage structure as represented in equation 15.

[ equation 15]

W＝W₁W₂

Here, W1 (first PMI) denotes a long-term/wideband characteristic, and mainly performs the role of beam grouping and/or wideband power control on each beam. W2 (second PMI) represents short-term/subband characteristics, and performs the role of beam selection in the beam group selected by W1 and co-phasing for each polarization of antenna ports having cross-polarization,

table 5 illustrates an LTE UL codebook for transmissions on antenna ports {20, 21 }.

[ Table 5]

Table 6 illustrates an LTE UL codebook for transmissions on antenna ports {40,41,42,43} with υ ═ 1.

[ Table 6]

Table 7 illustrates an LTE UL codebook for transmissions on antenna port {40,41,42,43} with υ ═ 2.

[ Table 7]

Table 8 illustrates an LTE UL codebook for transmissions on antenna port {40,41,42,43} with υ -3.

[ Table 8]

Table 9 illustrates an LTE UL codebook for transmission on antenna port {40,41,42,43} with υ 4.

[ Table 9]

NR may support the ability for a UE to report the maximum number of spatial layers (N) for UL transmission.

In addition, NR supports UL codebook of the UE based on the reported performance, and may support at least one of the following.

-alternatively 1: the network configures a plurality of codebooks corresponding to the number of antenna ports, respectively.

-alternative 2: the network configures a scalable/nested codebook that supports a variable number of antenna ports.

-alternative 3: the network configures a codebook that is the same as the UE capability.

Alternative 4. the UE recommends a subset of the codebook. This alternative may be included in at least one of the alternatives described above.

The codebook corresponding to a given number of TX antenna ports may be fixed to a particular codebook or may be configurable.

As the UL codebook structure, at least one of two types may be supported.

-alternatively 0: single-state codebook

-alternatively 1: dual state codebook

Reuse of the LTE codebook, impact on multiple panels, etc. will be considered when designing the UL codebook.

In NR, as a waveform of UL, both cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) and DFTs-OFDM can be used. Since waveforms like DFTs-OFDM are considered in LTE, it is a main design objective to reduce the peak-to-average power ratio (PAPR) in consideration of single carrier characteristics. As a result, in LTE, a codebook having cubic metric retention characteristics is used. Such a codebook has the property that for a rank >1, the layer power summation for each port is configured to be the same and includes a codeword (e.g., non-coherent/partial) that can turn off (or deselect/deactivate) a particular antenna port (antenna element in some cases, but hereinafter, for ease of description, commonly referred to as a "port") for a rank of 1.

The present invention proposes UL codebook construction/configuration/application schemes that can be applied to new wireless communication systems.

Before describing this, an exemplary UL data transmission procedure between the UE and the gNB is described with reference to fig. 15.

1) The UE performs (performance) reporting for Sounding Reference Signal (SRS) transmission/codebook configuration of the UE. At this time, the information that the UE can report may include the (maximum) number of antenna ports in a panel (or port group, hereinafter, generally referred to as "panel"), the number of panels (or port group, hereinafter, referred to as "panel"), Rx computation capability (e.g., whether a complex codebook like a DL type II codebook can be computed or whether non-linear precoding is supported, etc.), the number of UE-recommended ports for SRS transmission and/or codebook, waveform information (e.g., information on whether it is CP-OFDM or DFTs-OFDM), and/or whether multiple panels are transmitted, etc.

2) The gNB may indicate the SRS resource configuration information to the UE using Radio Resource Control (RRC), DCI, and/or MAC CE, etc., using the information reported from the UE. In this case, the information of the SRS resource configuration may include the number of SRS resources (N), the number of transmission ports of the ith SRS (x _ i) (i ═ 0.., N-1), and/or analog beamforming information per SRS resource, and the like.

3) The UE transmits the SRS to the gNB using the SRS-configured information received from the gNB.

4) The gNB may perform channel measurement and/or CSI calculation (SRS resource indicator (SRS), CQI, RI, Transmitted Precoding Matrix Indicator (TPMI), etc.) using the SRS transmitted from the UE, and notify the UE of information, MCS and/or UL power information, etc. through UL grant, etc. At this time, even when the gNB receives the SRS through the X port, the gNB can notify information of MCS, TMPI/RI, and the like calculated using the Y port TMPI/RI.

5) The UE may perform UL data transmission using the received information.

In the case where a UE is provided with a plurality of panels (or antenna port groups, hereinafter, generally referred to as "panels"), the factors for codebook design should be considered as follows:

number of panels supported in UL codebook

Number of ports supported per panel

Whether the UE can have a different number of ports per panel

In the case of designing a codebook by considering all parameters, codebook design may become very difficult. The present invention therefore proposes a codebook design that assumes a single panel (defined as a group of ports with similar signal to interference plus noise ratio (SINR), hereinafter generally referred to as a "panel"). Each panel may be tied/linked with SRS resources, and the plurality of antenna ports in each panel may be tied/linked with the plurality of SRS ports in each SRS resource.

Thus, panel selection may be performed by a single SRI indication received from the gNB. In this case, the PMI/RI/MCS corresponding to the number of SRS ports of the indicated SRI may be indicated to the UE. In case multiple (candidate) codebooks are indicated in the UL, the gNB may also indicate the codebook configuration to the UE. And/or, in case that a codebook suitable for CP-OFDM (i.e., default waveform) and a codebook suitable for DFTs-OFDM are designed differently, the UE may additionally indicate a waveform to be used and a codebook corresponding to the waveform to the UE by considering measured channel interference, etc. And/or using indicated MCS (SINR or CQI) information, UEs whose MCS (SINR or CQI) is a certain threshold or less (e.g., UEs whose geometry is not good) may operate based on DFTs-OFDM and possibly use a suitable codebook.

Hereinafter, a case where the gNB indicates M (M >1) SRS resources to the UE is described. In this case, the gNB may explicitly indicate a plurality of SRIs to the UE using a scheme such as bitmap, or may implicitly indicate to the UE using M SRS (resource) pairs/groups selected among N configured SRS (resources).

For example, description indicationsIs 2 (M-2). At this time, it is assumed that each resource is provided with X, respectively_i(i ═ 0,1) SRS ports, as described below.

-configured SRS resource 0 (X) of panel 0₀-a port),

configured SRS resource 1 (X) of panel 1₁-Port)

At this time, the UE may be assigned X₀、X₁The indicated port number, etc. is recommended to the gNB (e.g., when reporting performance). In case that two SRS resources are configured/applied to the UE, the UE may recognize that two panels are used and calculate a final PMI by configuring a plurality of panel codebooks. At X₀And X₁May use the PMI indicated for each resource in the same codebook (i.e., for rank1, v)₀，v₁) To configure the final codebookWherein the content of the first and second substances,v_i ^Hv_i＝1。

for the case of the panel configuration of the UE, in order to transmit/receive signals in all directions, a configuration facing opposite directions may be considered (for example, in the case where there are two UE antenna panels). In this case, since the vertex and/or the delay of the direction toward the gNB, the departure angle (AoD), the arrival angle (AoA), the deviation angle (ZoD) may be changed, panel correction is additionally required. Such a panel correction term may be denoted as γ ═ α exp (j θ). Here, the first and second liquid crystal display panels are,amplitude may be represented and θ (e.g., QPSK or 8PSK) may represent phase, and the gNB may additionally indicate information to the UE. At this time, for convenience of signaling, for example, the gNB may indicate that the configured 0 th order SRS resource may be assumed as a reference resource, and the UE is first configured with phase and/or amplitude information γ ═ α exp (j θ) only for the SRS resource. In this case, eventuallyThe codebook may be represented byAnd (4) configuring the form.

For rank2, the final codebook may be configured toAlternatively, the final codebook is configured asWherein the content of the first and second substances,and in this case, preferably, for each layerAre orthogonal to each other. The codebook is expressed as a codebook in which normalization is not performed, and in the case of performing column normalization, it is possible to express a codebookMultiplexed to a codebook. For example, rank2 of the LTE DL codebook may be applied.

This approach is to use the same co-phased structure for each layer/panel and, therefore, performance degradation is expected. Therefore, the present invention proposes to configure the channel correction term γ for each layer independently_i＝α_iexp(jθ_i) (i ═ 0,1) in order to support rank 2. Gamma ray_iIncluding phase and/or amplitude information. The channel correction term is applied only to WB and the payload can be reduced to the maximum. Alternatively, the channel correction term is applied to the SB, and the performance can be maximized. Alternatively, the amplitude and phase components may be applied by WB/SB (or SB/WB) separation. Alternatively, the number of bits corresponding to WB and SB are allocated/configured differently (e.g., WB-2 bits, SB-1 bit), payload size and performance may be balanced.

[ equation 16]

Wherein the content of the first and second substances,

in the case of the design according to equation 16, there is a problem that the panel correction term increases as the layer increases. To solve this problem, a scheme of limiting a transmission rank to 2 may be proposed to perform transmission based on CoMP operation such as coherent and/or non-coherent Joint Transmission (JT). Alternatively, in the case of a codebook used in transmission based on CoMP operation such as coherent and/or non-coherent JT, similar to "LTE DL class a codebook configuration 1", the codebook design may be limited to configure rank2 with only the combination of the same beams. In this case, regardless of rank1 and rank2, a panel correction term may be used, γ ═ α exp (j θ).

The rank1 and rank2 structure of codebook configuration 1 is shown in equation 17 below.

[ equation 17]

Rank 1:rank 2:

in the case where a codebook structure used in a single panel is configured with a dual-stage codebook (W ═ W1W2) for frequency selective precoding, a correction term γ ═ α exp (j θ) of the panel may be transmitted together with W1. And/or, for the case where the frequency selectivity of each SB is large, γ ═ α exp (j θ) may be transmitted together with W2. And/or, for a valid TMPI indication, the amplitude may be indicated by W1(WB or Partial Band (PB) cells) and the phase may be indicated by W2(SB cells).

The above scheme can also be applied to periodic and semi-persistent transmission as well as aperiodic (UL grant based) transmission. In addition, the proposed scheme is mainly described with UL codebook, but it is apparent that the scheme can also be identically/similarly configured/applied to DL codebook provided with multiple panels.

In case the gNB indicates SRI, MCS and/or TMPI + RI with UL grant, the following options may be considered.

1. DCI payload varying according to # of SRS resource: as an example of the above-described two configured SRS, the following options may be considered.

1-A: (SRI ═ 0) + (TPMI0) + (SRI ═ 1) + (TPMI1) + MCS (e.g., based on CQI) + RI: in the case of this method, the CQI is calculated by considering a single aggregate TPMI (TPMI0+ TPMI1) of the multi-panel (in this case, the proposed panel correction PMI may be additionally considered), and based on this, the MCS may be calculated. As a representative example, incoherent JT (or coherent JT in the case of additionally considering panel correction PMI) may be considered.

1-B. (SRI ═ 0) + (SRI ═ 1) + TPMI + MCS (e.g., based on CQI) + RI: in the case of this method, the CQI is calculated by selecting/applying TPMI in a codebook corresponding to the number of SRS ports considering a single aggregation of multiple panels (multiple port groups), and based on this, MCS may be calculated. As a representative example, coherent JT can be considered.

1-C (SRI 0+ TPMI0+ RI0+ MCS0 (corresponding to SINR0)) + (SRI 1+ TPMI1+ RI1+ MCS1 (corresponding to SINR 1)): in the case of this method, MCS may be calculated for each resource. To this end, the gNB indicates the calculated MCS0 to the UE by using the TPMI0 corresponding to the reference SRS resource, and may indicate the MCS1 to the UE by using a differential MCS representing a difference between SINR and SINR0 when using the aggregated TPMI. At this time, the RI may also be configured/indicated by the reference RI and the differential RI similar to the MCS, and only one complete RI may be configured/indicated as in the 1-a case.

2. Common DCI size: in the case of this method, the DCI size for the SRI, MCS and/or TPMI/RI indication may be set to a maximum value, for example, may be configured/indicated with a format such as (joint coding of two SRI indications) + (joint coding of two TMPI indications) + MCS + RI + additional TPMI (e.g., γ ═ α exp (j θ)).

In the case where a plurality of SRIs are used as described in the method, the SRI field may be configured as represented in, for example, table 10. Table 10 represents a configuration example of the 2-bit SRI field, and assumes that (SRS resources 1,2, 3, and 4) exist as configurable SRS resources.

[ Table 10]

Status of state	Number of SRS resources
		00	1
01	1,2
		10	1,3
11	1,2,3,4

In table 10, assuming that a 2-bit SRI is used, here, state "00" corresponds to the most preferred SRS resource or to a single selection of the most preferred panel, state "01" or "10" corresponds to a subset of the entire set of SRS resources, where two preferred SRS resources are co-transmitted, such as non-coherent/coherent JT, etc., and state "11" corresponds to the entire SRS resource, where all configured SRS resources are co-transmitted, such as non-coherent/coherent JT, etc.

In the case where each state is only used for using a specific resource selection, each state may be configured/applied with only a single value of the configured/selected resource, as represented in table 11.

[ Table 11]

Status of state	Number of SRS resources
		00	1
01	2
		10	3
11	4

Information of SRS resource selection corresponding to a state may be configured/applied by using a MAC CE or the like. In case that a plurality of SRS resources are configured to the UE, the size of the TPMI may be variably configured/applied according to the configured SRS resources.

As described above, the UL DCI format configured/applied according to the number of SRS resources (and/or the state of the SRI field) indicated by the SRI field may be exemplified as follows, and this may link/bind the indicated SRS or may be linked/bound with the SRI through separate signaling. And/or at least a portion of the information signaled by the UL DCI format may be indicated by separate signaling.

UL DCI format example 1

UL DCI format 0 (up to 30 bits) -case where a single SRS resource is configured (e.g., for use in obtaining UL CSI, regardless of SRS resource configured to be managed using UL beams (and/or use for DL CSI measurement)

A single TPMI field (4 bits),

a single TRI field (2 or 3 bits),

-RA, and/or

UL MCS, etc

In this case, TPMI and TRI may be jointly encoded.

UL DCI format example 2

UL DCI format 1 (maximum 50 bits) -case of configuring multiple SRS resources

Multiple TPMI + TRI fields (e.g., 4N bits) (where N may be the number of SRS resources configured (e.g., for use to obtain UL CSI))

[ case 1] -WB TPMI for each SRS resource + Single additional WB TPMI for TRI and/or inter-panel correction (e.g., γ ═ α exp (j θ))

Case 1 is a case where a TPMI equal to the above panel is additionally configured/indicated in WB unit so as to be used for incoherent/coherent JT or the like, with each WB TPMI + TRI according to the number of ports in the configured SRS resource.

[ case 1a ] -WB TPMI + TRI + per SRS resource (TPMI for SB units in phase between panels)

Case 1a is a case where each WB TPMI + TRI is configured to be utilized according to the number of ports in the configured SRS resource, and represents a case where the panel and the equal TPMI are additionally configured/indicated (frequency selective precoding) in units of SB so as to be used for incoherent/coherent JT or the like as described above. In the case where the panel is configured with "SB cells" in phase, more accurate panel correction can be performed, but a larger TPMI field size is required.

[ case 2] -TRI + Single WB TPMI + multiple SB TPMI

Case 2 corresponds to a dual-stage codebook (e.g., which operates like a dual-stage codebook by grouping based on specific properties in the LTE DL A-type codebook and a single-stage codebook (described below). Inparticular, case 2 is configured with a single WB TPMI according to the entire number of ports in the configured SRS resource, and corresponds to a case where each TPMI for each SB is configured/indicated.case 2 applies to a case where each SRS resource or panel is well calibrated like a coherent JT.

[ case 3] -WB TPMI + TRI + for each SRS resource (single TPMI for interplane inphase) + SB TPMI for selected SRS resource (pre-selected by RRC or MAC CE or selected by the lowest indexed SRI)

Case 3 corresponds to a case where WB TPMI and corresponding additional TPMI (panel corrector) are configured for each resource. Performance can be maximized when configured/applied with the SB unit as in case 1a or case 2, but the configuration of additional TPMI corresponding to the SB needs to be applied, and thus, the payload can be increased. Therefore, it is suggested to perform cooperative transmission only for WB in case of incoherent JT, and transmit SB TPMI only for a specific SRS resource (or panel) pre-configured, recommended by UE, or configured by RRC, MAC CE, or the like, or an SRS resource (or panel) corresponding to the SRI of the lowest index.

[ case 3a ] -WB TPMI + TRI + for each SRS resource (single TPMI for inter-panel co-phasing) + SB TPMI for selected SRS resources

Case 3a corresponds to the case where WB TPMI and corresponding additional TPMI (panel corrector) are configured for each resource in the dual-stage codebook structure. In order not to increase the TPMI of the panel in phase in the SB unit, it may be configured/applied so as to divide the SB into a plurality of sub-SBs and correspond to different resources of each sub-SB, and transmit the SB TPMI (for uniformly reflecting the SB TPMI for each resource), and this corresponds to fig. 16 (a). As shown in fig. 16(a), all four SRS resources (SRS resources #1 to #4) are transmitted in each SB.

Fig. 16(b) shows an embodiment in which SRS resources are mapped for each SB index and SB TPMI is transmitted. As shown in fig. 16(b), in the case where the number of SBs is greater than the number of SRS resources, first, the SB index and SRS resource index are in ascending order 1: 1 mapping, but SRS resources having a result value obtained by a modulo operation between a mapping target index and the number of SRS resources as their indexes may be mapped to remaining SBs that are not mapped, and SB TPMI may be transmitted (e.g., SRS resource #1 is transmitted in the case of the embodiment of fig. 16 (b)).

Fig. 16(c) corresponds to an embodiment in which SBs are allocated with a certain number of subgroups (e.g., 2, which is configurable), and in the case where the number of SRS resources is greater than the number of subgroups (four rows in the example), TPMI is transmitted in consecutive SBs. Even in this case, in order to uniformly transmit the TPMI to the entire SB, the SB with an index exceeding (the number of SRS resources/the number of subgroups, 2 in this example) is mapped together with the SRS resources by modulo operation. For example, in the case of the embodiment of fig. 16(c), SRS resources 1 and 2 are transmitted to SB 1,3, 5, etc., and SRS resources 3 and 4 are transmitted to SB 2,4, 6, etc.

As another example, a method of reducing the granularity of the SB may be considered. In this method, for example, in the case of a system in which the number of SRS resources is 2 and a single SB is 6 RBs, the configuration/application is such that the single SB is 12 RBs, and SB TPMI can be configured to be transmitted in two panels. By configuring this, advantageously, the payload according to the SB TPMI transmitted by the multi-panel may not increase.

As another example, a method of reducing the payload size of the SB TPMI by limiting/configuring to perform codebook sub-sampling or subset limitation in multi-panel transmission may be considered. In the case of codebook sub-sampling, codebook performance may eventually be degraded. Thus, to minimize degradation, the UE may recommend that codewords corresponding to a particular domain or direction must be included to the gNB.

As another example, the UL DCI format 1 may be configured/defined such that it includes at least a portion of the following.

An SRI field (2 or 3 bits),

single RI field (2 or 3 bits)/multiple RI fields (non-coherent JT case),

-RA, and/or

UL MCS, etc

In the present disclosure, several methods for TPMI (and/or RI) transmission are proposed. In case all methods or a subset are used, the gNB may explicitly or implicitly indicate the method actually used for the UE through signaling.

The implicit indication method has the following embodiments:

-number of configured (or activated) SRS resources: the UE can know the specific case of whether to use DCI format 0 or 1 according to whether the configured SRS is implicitly a single SRS resource or a plurality of SRS resources.

Parameters related to frequency selective precoding (e.g., on/off, number of SRS ports (interpretation of multiple PMI fields may be changed depending on whether frequency selective precoding is automatically activated or not in case the number of ports is X ports or more)): in the case where the number of ports is X ports (e.g., X ═ 4) or more, frequency selective precoding is considered, and a transmission method promised in advance between case 2 and case 3 or a configured transmission method may be used. In the case of X ports, it can be explained that the sum of all configured ports is X.

The number of layers (DMRS ports) or CWs (codewords) (e.g. in case of a 2CW range, two of RI and MCS are transmitted, respectively): since the case where there are two MCSs is interpreted in the sense of transmitting using non-coherent JT, the gNB may implicitly indicate to the UE the transmission method of the proposed (pre-committed or pre-configured) methods 1 to 3. In case of a 2CW range (e.g. for non-coherent JT, etc.) or in case the number of SRS resources is a certain number (pre-committed or configured) or more, the payload size indicated by the TPMI becomes larger, and in this case, the frequency selective precoding may be deactivated.

In the case of the UL DCI format 1 described above, coherent/non-coherent JT or the like that transmits multiple SRSs in cooperation is described as a use case. In the case of coherent JT, there is a possibility that TPMI corresponding to the panel corrector (phase and/or amplitude) does not work normally when the transmission timing intervals of each resource are separated by a predetermined time or more due to the influence of phase drift occurring due to the phase offset difference of the oscillator of the UE. Therefore, in the case where cooperative transmission is performed/applied in a plurality of SRS resources for the purpose of coherent/non-coherent JT, the transmission time interval between the SRS resources may be limited within a predetermined time. In the event that this is not performed correctly due to UE capabilities (e.g., an uncalibrated panel), the UE may report this as capability information to the gNB. In this case, only a single SRS transmission configuration/application to the corresponding UE may be restricted.

The above-described method is exemplified in the case where RI and PMI are jointly encoded and indicated. However, for valid TPMI indications of a dual-stage codebook like LTE DL, the above method can also be applied to the case where RI and PMI are encoded separately.

Hereinafter, a codebook configuration method assuming a single panel is described.

First, in the case of DFTs-OFDM, there is no need to support frequency selective precoding. Therefore, a single-stage codebook is suitable. In this regard, 2-port and 4-port in the LTE UE codebook may be used without any change when designing a single-stage codebook. The case of the 8-port codebook may be configured by using the LTE UL 4-port codebook, and the embodiment is as follows:

1. when v is_4，iDefined as the codeword with the i-th index in the UL 4 port, an 8-port rank1 codebook may be configured/defined asThis codebook is characterized in that this is configured based on a 4-port codebook, and more specifically, UL 4 ports are applied to 4 ports of 8 ports, and UL 4 port codewords apply phase shift codewords to the remaining 4 ports. At this time, the degree of phase rotation can be adjusted by the L value. For example, when the value of L is 4, the degree of phase rotation can be configured in QPSK, such as φ_n1, j, -1, -j, or configured in a subset thereof (e.g., -1 or-j). At this time, the 8-port rank1 codebook may be configured with a total of 16 × 4 or 16 codebooks (in this case, this may be used for the purpose of adjusting the number by the 4-port codebook size), and in the case where a higher resolution is required, a higher value (e.g., 8) may be set to the L value. Such L values may be configured to the UE by the gNB.

In case of an 8-port codebook, it is characterized in that the UE implementation complexity is reduced by using the same codeword as a 4-port TPMI and is designed by using an additional phase rotation value. This codebook can be applied equally to a dual stage architecture. For example, when W is W1W2In the structure of (3), the 4-port codebook may be represented by W1, and the phase rotation value is indicated by W2. In addition, this codebook is applicable to an X-pol (cross-polarization) antenna structure, and a 4-port codebook may be applied to antenna ports configured with the same polarization.

In addition, since the antenna is placed at an arbitrary position in the UE, the pass loss according to the antenna port position may be changed. To truly reflect this, the codebook may be separately configured by defining an alpha, which is a power control part/term in addition to the phase term in the codebook. Alpha may be defined/represented as alpha (e.g.,) And this may be used as PMI for W1. As a result, the final codebook may be defined as equation 18.

[ equation 18]

2. As another method, the final codebook may be defined as equation 19.

[ equation 19]

B is v_4，iAnd v_4，jCodebook size of

This codebook classifies the 8-port codebook into 4-port units (same polarization unit for X-pol) and is configured by applying a different 4-port codeword in each classified 4-port unit. In this case, for example, for rank1, the codebook payload size is configured to be 16 × 16. In this method of configuring a codebook with a dual-stage codebook, v_4，iIs designated as WB codebook and is used asIn addition, its codebook index is reported to be SB or shorter, andmay be configured. In addition, the antenna is located at an arbitrary position in the UE, and the pass loss according to the antenna port position can be changed. To truly reflect this, the codebook may be separately configured by defining an alpha, which is a power control part/term in addition to the phase term in the codebook. Alpha may be defined/represented as alpha (e.g.,) And this may be used as PMI for W1. As a result, the final codebook may be defined as equation 18.

[ equation 20]

In this codebook, in order to reduce the payload size of the codebook, only a portion of the LTE UL codebook may be used. For example, in a rank1 codebook, 16-23 (antenna off codebook) may be excluded. In addition, the principle can be applied equally to other higher ranks (e.g., ranks 2, 3, and 4). In this case, the codebook may be obtained by usingOrConfigured/defaulted in the same manner. Here, the superscript r denotes the rank. In addition, the proposed dual-stage codebook may be used for frequency selective precoding and may be applied to CP-OFDM. Otherwise, it is possible to restrict the single-stage codebook to be used for DFTs-OFDM and the dual-stage codebook to be used for CP-OFDM. The UE may recommend whether to use a single-tier codebook and/or a dual-tier codebook for the gNB, or the gNB may indicate to the UE through higher layer signaling (e.g., RRC, DCI, and/or MAC CE, etc.).

In addition, the 4-port codebook may be configured with only for rank1Or

In the following, codebook designs for frequency selective precoding are proposed in the context of e.g. CP-OFDM.

When it is assumed that the number of ports that the UE has in a single SRS resource is X, different delays are experienced for each X port, and this may be understood as a phenomenon in which the phase is shifted in the frequency domain. The delay on the time axis is interpreted as a phase change in the frequency axis, and the phase change on the frequency axis can be expressed as a function of frequency. For example, the phase variation on the frequency axis may be expressed as exp (-j2 π k δ), where k denotes an index corresponding to the corresponding frequency (e.g., subcarrier index, Physical Resource Block (PRB) (or Precoding Resource Group (PRG)) index, and SB index) and delta (δ) is a coefficient representing the frequency phase shift.

In the present invention, a codebook for frequency selective precoding using a frequency shift phenomenon occurring due to different delays experienced for each UL SRS port is proposed.

The proposed codebook structure is represented as in equation 21 for rank 1.

[ equation 21]

p_lIndicating the relative beam power based on the first port. This may be pre-promised to a particular value (e.g., p)_l{1,0.5,0.25,0}), or the gNB may indicate to the UE through higher layer signaling (e.g., RRC, DCI, and/or MAC CE).

The variable of the phase change value in equation 21 can be defined as equation 22.

[ equation 22]

In equation 22, δ is constructed_lThe variables of (c) can be defined as follows.

The η value may be indicated by higher layer signaling (e.g., RRC and/or MAC CE), or a pre-promised/configured value may be used for the parameter set. For example, the η value may be configured to be satisfied in {128, 256, 512, 1024, 2048, 4096}And, here,is the number of subcarriers in the Bandwidth (BW) configured for CSI reporting. The υ value is an oversampled value (fast fourier transform (FFT) size) and may be set to a particular integer value (e.g., 1,2, 4, etc.) (which may have characteristics of system parameters that are independent of a particular beam). The υ value may be automatically configured according to the parameter set, or the gNB may configure it to the UE. Finally, λ_lIs a value regarding the phase shift speed in BW configured for each port, and is, for example, when λ_lWhen 2, this may mean that the phase of the second port changes in the configured BW by as much as 4-phi. Lambda [ alpha ]_lThe value may be set to a particular integer value (e.g., 1,2, 4, etc.) and the gNB may configure it to the UE, or the UE may include therein, for each beam, a value that may be λ_lSelecting/specifying lambda from a set of candidate values of values_lAnd may feed it back to the gNB.

In the case of equation 21, δ may be calculated by using a value corresponding to the maximum delay of each port based on the time axis_lThe value is obtained. For example, in the frequency domain, a sample of each subcarrier/RB/SB is taken as a channel response to a corresponding port and an FFT is applied thereto, and then, may be transformed into a time domain signal sample. Among the time domain signal samples, the index corresponding to the maximum value (e.g., amplitude) may be determined as the value corresponding to the maximum delay, and δ_lMay be calculated based on the value. For example, in case the maximum delay value is a _1, this may be calculated as

Equation 21 shows a value calculated by assuming that there is one value corresponding to the maximum delay of each port. However, due to multipath, in cases where the delay spread is large, there may be a limitation to capture all of the fluctuations of the frequency domain channel by a single time domain signal sample. In this case, there may be a method of capturing multiple time domain signal samples (K samples, K may be configured by the gNB or recommended by the UE (specifically, the DL case). then, equation 21 may be expressed as equation 23.

[ equation 23]

In equation 23, the index k of each parameter may be understood as the kth sample determined by the commitment rule in advance from the kth maximum time domain sample or the maximum delay sample of each port. For example, in the case where it is determined that K is 3, the FFT size is 64, and the maximum delay is 7 th (tap), equation 23 may be constructed by using 6 th, 7 th, and 8 th (tap), time-domain samples. In addition, the gNB may be set to K ═ K₁＝..＝K_X-1And may indicate this to the UE. In the case where the correlation is small due to the large interval between ports, the gNB may be set to K₁≠...≠K_X-1And indicates this to the UE through higher layer signaling.

When K is 1, equation 23 may become equation 21, and for convenience of description, it is described by equation 21.

The remaining parameters in equation 21 may be defined/configured as follows.

The k index is an index value corresponding to a frequency and is configured according to/according to a given subcarrier or SB, and this is not additionally fed back. Epsilon_lThe value represents the phase offset value for the ith port, and as inOrIn the example of (a), a value configured such that the phase offset of each beam has a value such as QPSK, 8PSK, or the like may be additionally indicated with the port unit. Otherwise, the phase offset is ignored, and ε can be determined by subtracting ∈_lThe value set to zero significantly reduces feedback overhead.

Using the proposed method, the UE can calculate the SB SINR by using a method such as an average value based on TPMI by (for example) applying RE-level and report it to the gNB.

A more specific PMI estimation operation of the UE is as follows.

First, a channel represented by each subcarrier (or PRB or SB) may be defined asHere, N_RAnd N_TDenotes Rx of the gNB (or antenna element, hereinafter, generally referred to as "antenna port") and Tx antenna port of the UE, respectively. The UE may use H (k) per subcarrier, depending on frequency and offset ε_lEstimating relative power indicator p for PMI configuration_lA phase change factor delta for each beam_l. The gNB may collectively or independently indicate to the UE the factors representing the WB, and the UE may configure the TPMI based on this information. Otherwise, the gNB may indicate to the UE only a subset of the factors for TPMI configuration (e.g., excluding the relative power indicator p for TPMI configuration_lAnd, the UE may configure the TPMI based on the information. At this time, it may be assumed that the remaining information that is not indicated is predefined (e.g., p)_l,＝1)。

Hereinafter, a higher layer codebook configuration method using this method is described.

Generally, in the case of X ports, theoretical transmissions are available up to X layers, assuming that the gNB has more receive antenna ports than the UE. Thus, the gNB may use the channel between the UE and the gNB to calculate the optimal parameters for each layer. That is, the gNB can independently compute p for each layer_x,δ_x,ε_xAnd the like. In this case, the final precoderMay be defined as equation 24. In equation 24, R denotes a transport layer.

[ equation 24]

In the above codebook, independent PMI reporting is performed for each layer, and therefore, a problem may occur in which the payload size linearly increases as the layer increases. To address this issue, for a particular link, a single-stage, dual-stage, or particular codebook (e.g., a DL dual-stage codebook) may be used. Otherwise, using orthogonal codes represented by walsh codes, a codebook that is orthogonal up to layer 2 can be constructed. In this case, all the components related to the relative power in equation 24 may be fixed to 1. Then, the codebooks of rank1 and rank2 may be constructed as equation 25.

[ equation 25]

Otherwise, in case of the X-pol antenna, codebooks of rank1 and rank2 may be constructed as equation 26.

[ equation 26]

Phase correction term phi_nMay be indicated by different values for each WB or SB (e.g., independently of each other).

Hereinafter, a manner in which the proposed single panel-based codebook or the existing LTE UL/DL codebook is applicable to a plurality of panels is described. Hereinafter, for convenience of description, it is assumed that the same number of antenna ports are provided to a single panel. That is, hereinafter, in the case where there are M panels, it is assumed that N X-pol antenna ports in each panel exist in each polarization. In the case of the proposed codebook structure proposed below, the function of port selection or the like can be handled by separate signaling such as SRI, and therefore, it is characterized in that port selection or the like in the codebook (for example, in the case where the codebook element is set to zero) is not considered.

First, in case of configuring an X-pol antenna (2-port), it is assumed that a DL or UL 2-port codebook is used. In this case, a 2-port codebook may be constructed as follows. Since no beam group is needed for 2 ports, W1(2 by 2) can simply be assumed to be an identity matrix. In addition, co-phasing for each polarization may be performed for W2 (in SB and/or short term). That is, W2 may be configured asAnd can pass phi_n1, j, -1, -j, or 8PSK configurations. Here, i may be a panel index. In this case, the final codebook may be represented by the LTE DL codebook (assuming QPSK in-phase).

[ Table 12]

Using table 12, a constructed codebook in which a plurality of SRS resources are combined may be represented as follows.

For a 4-port, e.g., non-coherent JT, two antennas are provided for each resource (panel) and a 2-port codebook is used and the phase between the resources (panels) and/or amplitude correction terms can be considered. That is, this is represented by the mathematical expression, equation 27.

[ equation 27]

Here, w_li∈I₂，And, alpha, beta represent correction terms for amplitude and phase correction between resources (panels) (e.g.,β ═ {1, j, -1, -j }). α, β may be commonly configured/applied for WB or SB to either of the two values (α × β). At this time, in order to effectively change the payload, different bit sizes (e.g., WB ═ 2 bits, SB ═ 1 bits) may be configured/applied to the WB and SB. In addition, efficient application of each layer, e.g., α for rank1¹，β¹Alpha for rank2²，β²α, β may be applied to each layer independently. However, since the rank2 configuration of the 2-port codebook has a structure using the same beam for each polarization, it may be preferable to use the same α, β in order to save the payload size. This may be equally applied to a codebook in which the W1 beam set is configured with 1 beam and a 2-port codebook.

As another embodiment, by configuring as α ═ {0, 1}, it is possible to configure the amplitude component to perform only the function of panel selection. In this case, since the size of the TPMI varies according to the α value (i.e., the size of the TPMI doubles in the case of α ═ 1), it may be preferable that the TPMI and the correction term and/or RI are jointly encoded in terms of the TPMI payload.

The codebook is extended and applied to an 8-port codebook, which can be represented as equation 28.

[ equation 28]

That is, each of the four resources (panels) uses a 2-port codebook, and the correction term of each panel may be increased according to the number of panels. To solve this problem, for phase, by e.g. β₂＝β²，β₃＝β³，β₄＝β⁴Or beta₂＝β，β₃＝2β，β₄3 β operation, which may be configured/applied to be represented by a single value. At this time, the gNB may configure to the UE which panel correction value to use on the UE, and since the panel correction value may be changed according to the UE's antenna implementation, the UE may notify the gNB of the panel correction value through a capability report. The remaining elements of the 8-port design may be configured/applied the same as in the 4-port case described above. The normalization term of the codebook may be calculated as

Hereinafter, a single panel is configured with a codebook for the case of 4 ports (or the case where the number of aggregation ports is 4 in the case of coherent JT). In the case of the 4-port codebook, when a dual-stage codebook is configured, an LTE-A A-type codebook may be extended and used, or a Release-12 eDL-MIMO 4Tx may be configured and used. In case of using the class a codebook, the codebook structure may be limited to a structure in which W1 is configured with one beam (e.g., represented as configuration 1, etc.) in order to reduce the payload of TPMI (e.g., the payload size of SB) and W2 may perform frequency selective precoding in phase.

Table 13 illustrates a 4-port codebook (LTE DL 4 port).

[ Table 13]

In the context of table 13, there is shown,i denotes a 4 × 4 identity matrix.

As another embodimentThere is a scheme of configuring frequency selective precoding by using an LTE DL single-stage codebook. In this scheme, the 4-port codebook of fig. 13 is grouped in units of L indices (e.g., L ═ 2, 3, 4, and L is configurable by a gNB or a UE) and configures W1, and beam selection can be selected by W2 (within the W1 group). For example, in the case where L ═ 2, the rank1 codebook may be constructed asw₂＝e_j. The information of the beam selection may be additionally/independently signaled. For example, the beam selection information may be signaled in L x 4 bits for a codebook, or jointly indicated by using permutations for reducing overhead or combining selected beams as described below. In the codebook, e_j∈C^L×1Is a selection vector and a vector where only the jth element is "1" and the remaining elements are "0". In addition, in the codebook, the superscript r corresponds to the rank.

The above embodiment is a scheme of grouping L beams according to a specific method and selecting/indicating a group index using W1 and performing beam selection/indication using W2. However, the embodiment presented below is a scheme of allocating a different index to each of the L beams and explicitly indicating an index of the selected beam (e.g., for L ═ 2, beam index (11,5) is indicated). In this case, the number of cases required for the indication may be₁₆P_L,16C_L(permutations and combinations). In the case of the number of cases calculated by the permutation operator, the beam order in which W1 is constructed between the UE and the gNB is not ambiguous, but there is a disadvantage in that the number of signaling bits increases. In the case of using a grouping method constructed by combination, it can be assumed that the grouping is always arranged based on a low (or high) codebook index. Without pre-commitment like such an example, precoder cycling such as semi Open Loop (OL) for fast UEs may be used and which grouping method to use may be configured and the gNB may indicate it (or the UE may recommend it). The performance of frequency selective precoding by beam grouping has great advantages in terms of signaling overhead.

As another method, a method of grouping the Householder 4Tx codebook of L ═ 4 is as follows.

Table 13 is represented by each codebook index and is arranged as represented in table 14.

[ Table 14]

The numbers in brackets { } in table 14 indicate the positions of the selected basis vectors/codewords in the basis vectors/codewords. For example, in table 14, {14} for rank2 of codebook index 0 may be interpreted as the first (b0) and fourth (b7) basis vectors/codewords in basis vector/codeword [ b0, b5, b6, b7 ].

The vector represented in table 14 may be defined as equation 29.

[ equation 29]

Table 14 shows an embodiment of grouping it with codebooks of the same basis vectors/codewords. For example, referring to table 14, codebook indices 0,2,8, and 10 configured with the same basis vector/codeword [ b0, b5, b6, b7] may be grouped into one group. In the case represented as table 14, the LTE DL 4-Tx Householder codebooks may be sorted/grouped based on the same base codeword (of course, different codebooks are applied by phase or conjugate operations). That is, based on the codebook index represented in table 15, the Householder 4Tx codebook may be divided/grouped into beam group 1 {0,2,8,10}, beam group 2{12,13,14,15}, beam group 3{1,3,9,11} and beam group 4 {4,7,5,6 }.

[ Table 15]

Beam set 1	0,2,8,10
		Beam group 2	12,13,14,15
Beam group 3	1,3,9,11
		Beam group 4	4,5,6,7

Thus, the assigned index in each beam group may be indicated by WB (and/or long term) and the best beam in each beam group may be indicated by SB (and/or short term).

The normalization term is not reflected in equation 29. The normalization can be performed byMultiplication by the codeword (corresponding to k and rank) for each codebook index, where, 2 means per-column normalization,meaning the normalization of each rank, and where R represents rank.

The codebook classification/grouping method may be to classify/group according to the separation distance/degree between ports (e.g., classify/group according to the x value in x λ port separation). Otherwise, the codebook sorting/grouping method may be to sort/group according to the granularity degree of phase shift between ports (i.e., each of the sorted codebook groups may have different/divided/independent phase shift granularities) (e.g., shift the beam groups 1 and 2 by Binary Phase Shift Keying (BPSK), shift the beam group 3 by Quadrature Phase Shift Keying (QPSK), and shift the beam group 4 by 8-PSK), and according to this, divide the WB codebook. Therefore, even in the case of expanding the extension codebook of a specific beam group according to the attribute, codebook-based frequency selective precoding can be performed. For example, in the case where the beam group 3 is extended, that is, a codebook example of a codebook is constructed by substituting q0 and q1 into q2 and q3 defined in equation 30, respectively.

[ equation 30]

In the above example, for TPMI indication, a 2-bit signaling overhead for each of WB and SB is required. Since rank4 corresponds to a full rank of 4TX, it may be committed/configured to simply use the identity matrixOr a representative rank4 codebook may be used for each group. Otherwise, in order to reduce the signaling overhead of the SB, a method of recombining the beam groups 1,2, 3, 4 to L ═ 2 may be considered. For example, the above grouped beam groups 1,2, 3, 4 may be classified/grouped into beam groups 1,2, 3, 4, 5,6, 7, 8 (i.e., classified/grouped into codebook indices {0, 2}, {8, 10}, {12,13 }, {14, 15}, {1,3}, {9, 11}, {4, 7}, {5, 6}, etc.), and in this case, each SB may represent TPMI with 1 bit.

As another grouping method, a grouping method may be proposed by using a distance between codewords of each rank or correlation. To this end, as an example of the available metrics, there may be chord distance (d (a, B)) or matrix (vector) correlation (Corr (a, B)), and this may be represented by equation 31.

[ equation 31]

Corr(A，B)＝||AB^H||_F

Here, A and B are arbitrary matrices (vectors) of the same size, and the super script "H" represents a conjugate transpose (Hermitian), and | | · | | luminance_FRepresenting the Frobenius norm.

Examples of codebook groupings of ranks 1 and 2 in table 13 may include table 16 by using metrics.

[ Table 16]

	Rank1	Rank2
			Beam set 1	0，2，9，11	0，3，7，11
Beam group 2	1，3，8，10	1，2，8，10
			Beam group 3	4，7，12，15	4，5，6，12
Beam group 4	5，6，13，14	9，13，14，15

Each index in table 16 corresponds to an index of a codeword of table 13. This is an example of performing grouping based on the degree of correlation between codewords. This may mean that the correlation between WB-SB TPMI is maintained, and frequency selective precoding may be performed in case that there is a certain degree of correlation between codewords. In addition, as represented by the example of table 16, the beam groups may be different for each rank. This is because as the layers increase, the metric can be changed by the orthogonal beams included in W1.

Hereinafter, TPMI overhead reduction techniques are proposed.

-proposal 1: the information of the above grouping method may be indicated by the TPMI through DCI. However, in terms of overhead reduction, information of a beam grouping method or a beam group arbitrarily indicated from the gNB may be indicated by higher layer signaling such as MAC CE, and the TPMI related to WB/SB may be indicated by using a beam in the beam group indicated/selected by TRI and MAC CE as DCI.

-proposal 2: in the above example, the bit widths of WB and SB are set identically. In this case, a bit width larger than that of SB is allocated to WB, but SB is limited to a specific bit width (e.g., 1-bit indication, etc.), and overhead can also be reduced.

-proposal 3: in the case of reporting in the SB unit, the size of TPMI becomes larger as the number of SBs increases. To address this issue, it may be pre-promised/configured to perform sub-sampling in SB mode transmission. At this time, the sub-sampled information may be promised in advance between the UE and the gNB, or indicated to the UE through a higher layer such as MAC CE or the like or a codebook subset restriction method, which will be described below.

-proposing 3-1: since sub-sampling may significantly degrade UL performance, it may be committed/configured to perform sub-sampling when the number of SBs to be scheduled to the UE is a certain N (e.g., N-3), and not otherwise.

The proposed method can be used/applied for the purpose of reducing overhead of UL/DL transmission based on a dual codebook structure.

In case that TRI + TPMI is indicated with a single DCI and the size of TPMI is changed according to TRI, TRI + TPMI may be jointly encoded and transmitted in order to reduce overhead.

TPMI can be divided into TPMI1 (corresponding to W1) and TPMI2 (corresponding to W2) (hereinafter, generally referred to as "TPMI 1" and "TPMI 2"). At this time, TRI/TRI + TPMI1 may be indicated by a single DCI, and TPMI2 (and/or location information of a corresponding SB) may be indicated by a MAC CE or the like. In this embodiment, there is an advantage in that frequency selective precoding can be performed without signaling overhead of large DCI even in the case where the size of SB precoding is large.

Alternatively, in contrast, TRI/TRI + TPMI1 may be indicated by MAC CE or the like, and TPMI2 may be indicated by DCI. As in the case of the WB transmission mode, this embodiment can be advantageously applied to a case where the number of SBs is small (e.g., 2) or where RI or TPMI is relatively dynamically changed.

Where indicated by dual DCI, the DCI may be configured/classified into a first DCI and a second DCI. Where the first DCI has a higher priority than the second DCI and/or the second DCI is indicated with a relatively long term compared to the first DCI, the TRI may be included in the first DCI and encoded separately for higher protection or jointly encoded with TPMI1, and TPMI2 may be included in the second DCI.

The TRI, TPMI1, and TPMI2 information related to precoding may have interdependencies, and thus, even in case the UE cannot decode at least a part of the corresponding information, the UE may interpret/decode the TRI, TPMI1, and/or TPMI2 indicated based on the previously received information. Otherwise, as a default behavior, transmissions with rank1 and/or WB modes may be promised/configured in advance between the gNB and the UE.

In the case of an 8-port codebook, a 4-port codebook may be applied to each panel (resource), and the corresponding codebook structure is as represented in equation 32.

[ equation 32]

v₁∈C^2×1，

Hereinafter, when UL (or DL) is transmitted with a very wide BW (e.g., 40MHz) in NR, a case where frequency selective precoding is applied/performed is described.

In general, in frequency selective precoding, beam selection and co-phasing in the SB manner are performed in a dual-stage codebook structure by using a beam (or a relative beam) existing in a beam group of W1. In the case of constructing L beams of the beam group of W1, it may be best to configure the L value in order to reflect the frequency selective precoding well in the case where the frequency selective characteristic is dominant or in the case where the BW is very wide. Therefore, the L value may be configured according to/based on BW (e.g., BW ═ 10MHz (L ═ 1), — 40MHz (L ═ 4), etc.). And/or the gNB may indicate the L value as the L value of the UE by considering frequency selectivity, or the UE may recommend the L value preferred by the UE.

In addition to the above codebooks, other LTE codebooks, for example, a class a codebook may be considered as being used as the UL codebook. In this case, since the TPMI indicated by the DCI linearly increases according to the number of SBs, in order to limit this, it may be limited to use only "configuration 1" in which the SB payload size is the smallest.

For DFT-S-OFDM, in case WB TPMI is used for 2Tx, a rank1 precoder represented in the following table 17 may be used. In the following table, the "codebook index" may be referred to as "TPMI index".

[ Table 17]

For CP-OFDM, TPMI indices 0 to 3 for rank1 and TPMI indices 0 and 1 for rank2 may be used. In addition, one of two antenna port selection mechanisms may be supported.

-alternatively 1: in table 17, TPMI indexes 4 to 5 of rank1 and TPMI index 2 of rank2 are used in CP-OFDM.

-alternative 2: SRI indicates the selected antenna port.

For 2Tx, the TPMI, SRI, and TRI of release 15 may be forwarded by using a single level DCI of a semi-statically configured size. According to the PUSCH resource allocation of the single-level DCI, the DCI size included in the TPMI, SRI, and TRI is not changed. A UE capability may be implemented that identifies whether a UL MIMO capable UE can support coherent transmission over its own transmission chain.

For 4Tx CP-OFDM, the following method can be considered as a method of handling port selection in the codebook.

1. Configurable codebook

A. A port combination codebook and a port selection codebook are distinguished and each port can be signaled by a higher layer. That is, similar to the port selection codebook for antenna turn-off function represented by the UL LTE codebook (or a subset thereof) and the codebook represented by the Household codebook/NR DL type I CSI, may be signaled by a higher layer such as RRC to use a codebook in which there are non-zero coefficients in all ports in the port combination codebook. A UE configured with beamformed SRS (in case of an extension to the UL of class B similar to LTE eFD-MIMO) may use a port selection codebook.

2. Single codebook

A. This is a codebook represented by a union of ports of the port combination codebook and the port selection codebook, as in case 1.

3. When the codebooks configured with methods 1 and 2 are used, TRI and TPMI may be independently coded or jointly coded. In case TRI and TPMI are jointly encoded, only ports are allowed to be selected to a specific rank or lower (e.g., rank1 or rank 2) in order to reduce the overhead of DCI. In case of using the method a, which is configured with a port selection codebook, and TRI is indicated by 3 or 4, the UE may recognize the indicated TPMI as a TPMI corresponding to ranks 3 and 4 of the port combination codebook.

Hereinafter, in the case of using the above-described UL codebook (e.g., precoder cycling), a method of indicating codebook subset restriction in the gNB for interference control is proposed. This may be used for the purpose of reducing signaling (e.g., DCI) overhead for higher layer signaling. That is, the purpose of this method is to reduce overhead in preparation for the case where the TPMI size becomes large due to the above-described frequency selective precoding/multi-panel operation or the like. Therefore, in this approach, one can consider the case of codebook reconstruction/sub-sampling as a codebook that includes a particular angle and domain preferred by the UE. In this case, there is an effect of payload size reduction because the reconstructed and/or sub-sampled codebook size is smaller than the existing codebook.

1. Codeword (beam) unit: this is a method of indicating that a complete codeword of an UL codebook is constructed by a scheme such as a bitmap for Cell Specific Reference (CSR) indication. Thus, the number of bits used for CSR is L₁+L₂+...+L_X. Here, L_iIs the number of i-layer codewords.

A. In case of a 2D DFT based codebook for CP-OFDM, the entire grid of beams (GoB) may be indicated by the value of N1N2O1O 2. Here, each of N1, N2, O1, and O2 is the number of antenna ports and the number of oversampling in the first and second domains.

B. Domain-specific CSR or angle-specific CSR: for example, where the angular spread of the vertical domain is very small, the codebook for the vertical component may not impact performance. The gNB may be known by measurement/monitoring of the channel between the UE and the gNB, or the UE may recommend it to the gNB.

2. A codebook configuration unit: in the case where the UE uses multiple codebook configurations, the UE may recommend a preferred codebook or a non-preferred codebook to the gNB for CSR purposes.

3, Rand unit: when an indication of a CSR having a particular rank is received, the UE does not use a codebook corresponding to the respective rank.

A. For each rank, method 1 and/or method 2 may be combined and CSR may be indicated. That is, for each rank, the beam/beam group to which codebook subset restriction applies may be indicated independently (e.g., due to UE coherent transmission capability, etc.). For example, in the case of a 2-port codebook as represented in the following table 18, a bitmap of B _ rank1 may be configured with 2 bits, and it may be promised/configured that indexes 0 to 5 are used when the bitmap is "11", and indexes 4 and 5 are used when the bitmap is "01". In addition, when the bitmap is "11", the 2-bit map that can promise/configure B _ rank2 uses codebook indices 0 to 2, and when the bitmap is "01", only codebook index 2 is used.

[ Table 18]

To reduce signaling, the beams/beam groups may be indicated by a common coding format rather than a bitmap format. For example, a 1-bit size is defined for the indication, which may define that a bit indicates "01" in a 2-bit bitmap example when the bit is "0" and indicates "11" in a 2-bit bitmap when the bit is "1".

In this method, independent indication for each rank is represented, but in case that the bitmap size defined for each rank is the same, all ranks may be limited to a single bitmap (i.e., all rank limits may be indicated by respective bitmaps).

W2 unit: in the case of a dual stage codebook (similar to a particular in-phase or LTE DL class B codebook), W2 corresponding to a W2 codeword may be constrained to restrict the use of a particular port. In this case, the UE may assume a rank-1 constraint or information corresponding to the rank may be indicated to the UE together.

5. A panel unit: in the case where the panel indication is included in the codebook, to limit the transmission of a particular panel, the gNB may indicate to the UE a constraint corresponding to the codebook usage of the particular panel through the CSR (i.e., indicate panel on/off with codebook subset constraints).

The gNB naturally indicates most of the CSR to the UE. However, in case beams of each panel interfere with each other during a procedure in which the UE performs a CoMP operation such as JT or Joint Reception (JR), the UE may recommend CSR of the proposed method to each gNB for control. As a more specific example, in case the UE is provided with two panels and the best corresponding Rx panel is different for each panel (in case the preferred panel/TRP is different for each panel), it is considered that the link between the two panels/TRP and the UE fails. That is, for example, when the link between TRP1 and UE panel 1 is referred to as link 1 and the link between TRP2 and UE panel 2 is referred to as link 2, link 2 is considered to have failed. In this case, as an exemplary operation, the UE abandons link 2 and combines the ports of panel 2 for link 1, and more robust transmission may be considered. In this case, when using the transmission beam in the existing TRP2 of panel 2, interference can be significantly reduced with TRP2, and therefore, when combining panels, the UE can suggest to drop/prohibit the use of the corresponding beam for the gNB. This example can be used even in the case of a beam pair link failure due to blocking or the like. That is, to reduce interference of other TRPs/panels, the UE may suggest not to use TPMI, digital and/or analog beams that significantly interfere with other TRPs/panels.

In the case of 4Tx using wideband TPMI, at least a single level DCI may be used. One alternative may be chosen for the wideband TPMI and NR 4Tx codebooks for CP-OFDM.

-alternatively 1: release-10 UL, there may be other entries:

-alternative 2: version-15 DL, there may be other entries:

-alternative 3: version-8 DL, there may be other entries:

NR supports 3-level UE capability for UL MIMO transmission:

-full coherence: all ports can be sent coherently.

Partial coherence: the port pairs can be sent coherently.

-non-coherence: no port pair can be sent coherently.

So that TPMI codewords from the codebook are used by the gNB.

For 1 SRS resource, the number of SRS resources,

-full coherence: all ports corresponding to ports in the SRS resource can be coherently transmitted.

-incoherent: all ports corresponding to ports in the SRS resource are not transmitted coherently.

Partial coherence: a port pair corresponding to a port in the SRS resource can be coherently transmitted.

In addition to codebook-based transmission using one SRS resource, codebook-based transmission using multiple SRS resources including non-coherent inter-SRS resource transmission may be supported.

Non-coherent inter-SRS resource transmission: two DCIs may be used, and one TPMI per DCI may be used. In addition, one TPMI/TRI per SRS resource may be signaled and may indicate the selection of multiple SRS resources.

At least a single SRS resource is configured and an additional 4Tx rank1 codebook may be supported for DFT-S-OFDM as represented in table 19 below.

[ Table 19]

For DFT-S-OFDM, an LTE 4Tx rank 1UL codebook for TPMI 0-15 may be supported. At this time, additional codewords for antenna port selection may also be supported.

In view of the above, the UE may additionally report capability information related to coherent transmission to the gNB. In this case, in order for the gNB to configure the codebook to the UE, capability information such as the number of (maximum) antenna ports in a panel (or port group), the number of panels may be additionally considered in addition to information such as antenna configuration, antenna polarization, and the like. Depending on the UE implementation, these capabilities of the UE may have various values and require much effort to implement it.

Thus, the present disclosure proposes to report UE-preferred UL codebook subset constraints to capable gnbs. Such UL codebook subset restriction may be a codebook to which codebook subset restriction is applied to the codebook. For example, a 3-bit capability report may be provided as table 20. Table 20 illustrates codebook subset constraints, and table 21 illustrates a 2-port codebook for the definition of table 20.

[ Table 20]

Status of state	Codebook structure
		000	2-port with TPMI indices 0-5 for rank1 and 0-3 for rank2
001	2-port with TPMI index 4-5 for rank1 and 3 for rank2
		010	4-Port with TPMI indices 0-27 for rank 1TBD of ranks 2-4
011	4-Port with TPMI indices 16-27 for rank 1TBD of ranks 2-4
		100	4-Port with TPMI indices 24-27 for rank 1TBD of ranks 2-4
101	Retention
		110	Retention
111	Retention

[ Table 21]

For the definition of table 20, the 2-port codebook of table 21 and a 4-port codebook to be described below are used. The "000" or "001" state exemplifies a collective report for each rank. In case of independently indicating the capability for each rank, the reporting field of each rank may be independently defined/configured.

Otherwise, in case the waveform types of the supported codebooks differ, the UE capabilities may be reported with a separate capability field (depending on the type of waveform). The rank1 codebook is the same regardless of the waveform (e.g., for 2-port), the same rank1 codebook is used regardless of the waveform, and thus, the capability may be reported in the same field with the same status, and the gNB may reflect this for all waveforms. For 4-port, since different codebooks may be used for waveforms, it is preferable in terms of flexibility to report the UE capability with a separate capability report field.

Alternatively, the capability field of the UE may be distinguished into independent fields according to whether the UE is WB TPMI or SB TPMI.

For higher flexibility, it may be considered that a method of indicating UE capability in a bitmap format may be used. B _ DFT-s-OFDM may be indicated by a bitmap (a bitmap associated with DFT-s-OFDM). For example, for a2 port, it may be indicated by 1 bit corresponding to TPMI indexes 0 to 3 and a2 bit bitmap corresponding to 1 bit of TPMI indexes 4 and 5. For example, when the 2-bit bitmap is "11", this indicates that the UE can use all TPMI indices 0 to 5 as the capability of the UE, and when it is "01", this indicates that the UE can use only TPMI indices 4 and 5 as the capability of the UE, and can construct a codebook based thereon. In addition, in 4 ports, the UE capability is represented by a 3-bit bitmap. When the 3-bit bitmap is "111", this indicates that the UE can use the TPMI indexes 0 to 27, when the 3-bit bitmap is "011", this indicates that the UE can use the TPMI indexes 16 to 27, and when the 3-bit bitmap is "001", this indicates that the UE can use the TPMI indexes 24 to 27.

For B _ CP-OFDM, a bitmap for each rank may be added. The bitmap size for each rank may be different. That is, the B _ CP-OFDM may be constructed by a union of each rank bitmap. For example, B _ CP-OFDM may be configured/indicated by a bitmap scheme, such as { B _ CP-OFDM _ rank1, B _ CP-OFDM _ rank2, B _ CP-OFDM _ rank3, B _ CP-OFDM _ rank4}, where B _ CP-OFDM _ rank represents a bitmap for each rank. In the case where CP-OFDM and DFT-s-OFDM share the same rank1 codebook, the UE can report this capability through a single bitmap (i.e., B _ CP-OFDM). Here, the capability according to the number of ports may be reported through an independent bitmap, and the reported bitmap (more specifically, the number of independent bitmaps) may be configured according to the maximum port number supported. For example, in case of the supported maximum port number of 4, the UE may report all the capabilities of the 2-port and 4-port codebooks, but in case of the supported maximum port number of 2, the UE may report the capabilities for the 2-port codebook only in a bitmap format.

The TRI in LTE may be indicated by a DCI of 5 to 6 bits jointly encoded with the TPMI. However, NR supports CP-OFMD, information for indicating DMRS, antenna port, scrambling identity, and layer number may be indicated by DCI related to DL as in table 22.

[ Table 22]

Therefore, in the UL of NR, similar to this information, information of an antenna port, scrambling identity, and the number of layers may be indicated in DCI related to the UL. In this case, in the case of a UE supporting UL codebook-based transmission, indication of layer information (e.g., information of TRI) is overlapped, and thus, DCI may be wasted. Therefore, in case of information indicating an antenna port, a scrambling identity, and a number of layers in the UL-related DCI, the TRI may be indicated with a field, and the TPMI may be encoded and indicated with a single/independent field. At this time, since the TPMI size of rank1 is the largest, the TPMI size may be configured according to rank 1. The codebook is designed so as to match the configured TPMI size with the maximum value of TPMI corresponding to ranks 2 to 4, or in case the number of TPMI of the respective ranks is smaller than the TPMI size (e.g., for rank4 of 4 ports, since it is a full rank, e.g., the TPMI number is about 1 to 3, and in case the rank 1TPMI size is 5 bits), (32-3 ═ 29 remaining states are available for using error checking.

In the case of performing codebook-based UL transmission from a plurality of SRS resources as described above, in particular, in the case of incoherent transmission represented by incoherent JT, as described above, there may be various options, which may be arranged as the following examples:

the following is an example of performing codebook-based UL transmission based on two SRS resources. Here, TPMIi and TRI denote TPMI and TRI of the ith SRS resource, respectively.

A. (SRI ═ 0) + (TPMI0) + (SRI ═ 1) + (TPMI1) + TRI: in this option, only one TRI is indicated in common for both SRS resources, and TPMI may be indicated independently for each resource indicated by each SRI. .

B. (SRI ═ 0) + (SRI ═ 1) + TPMI + TRI: this option represents a case where SRS ports in two SRS resources are aggregated and transmitted by using a single TPMI, and here, TRI may be indicated as single.

C. (SRI ═ 0+ TPMI0+ TRI0) + (SRI ═ 1+ TPMI1+ TRI 1): this option follows the option of a, but corresponds to the case where TRI is indicated for each resource.

As described above, the TRI may be indicated in the DMRS table. When using option a, the TRI may be interpreted as the total rank of the UE performing UL transmission. At this time, in the case of indicating a layer by using a plurality of resources, it may be ambiguous that the number of layers is indicated/mapped to a specific resource. For example, in case of performing UL transmission in two resources, the total rank is 3 and it is indicated in a DMRS table with TRI-3 that whether the rank transmitted in each resource is (TRI0, TRI1) ═ 1,2 or (2,1) is ambiguous. Thus, an additional indicator (e.g., a 1-bit indicator) for clarification may be used/defined. And/or, in case of being indicated by a specific TRI (e.g., TRI-3), a rank of transmitting a corresponding resource in the SRI field may be indicated. For example, when the total rank is 3, it may be promised between the UE and the gNB to always indicate the resources for rank 2-transmission first. That is, as represented in the following table 23, in the case where TRI is 3, the state "01" means that the 0 th resource is rank2, and "10" means that the first resource is rank 2.

[ Table 23]

Status of state	Number of SRS resources
		00	0
01	0,1
		10	1,0
11	0,1,2,3

Even in the case of TRI1, similarly to the case of TRI 3, the fact of transmitting the resource of rank1 may be explicitly or implicitly indicated with an additional indicator. Otherwise, in case of TRI ═ 1, since rank1 transmission is performed in only one resource, only a single resource may be indicated in the SRI state.

In case of TRI ═ 1, rank 2-transmission is performed in the selected one resource, or rank1 transmission may be performed in each resource. In the former case, like rank1, in the SRI state, there is only one resource (the selected resource performing rank 2-transmission), and in the latter case, it can be understood that rank1 transmission is performed in each resource, and therefore, there is no ambiguity.

In case of TRI-4, it can be understood that rank-2-transmission is performed per resource.

This example represents a case where two SRS ports are provided in every two resources, respectively, in the case where the number of ports for total UL transmission is 4.

For example, in the case where the number of ports used for total UL transmission is 4 or more, a case where coherent/non-coherent UL transmission is performed by two resources is described, and four SRS ports are used for each resource. In addition, in this case, it is assumed that the total transmission rank is 4. Then, in case of non-coherent transmission, the rank of each resource can be indicated without ambiguity by the proposed option/method until the TRI < ═ 3 case. However, in case of being indicated by TRI-4 and performing rank-4 transmission in one resource, SRS resources transmitted in the SRI field are respectively indicated, and thus, ambiguity can be resolved. However, because there may be ambiguity as to whether (TRI0, TRI1) ═ 1,3), (2,2), or (3,1) may exist, the indicator for discrimination may be signaled separately. Otherwise, the total TRI may be the indicated DMRS table, and may be jointly encoded with the TPMI in the TPMI field and indicate the TRI transmitted in each resource. That is, the DCI may be configured with at least one of the following.

-SRI

-one TRI embedded in DMRS

TPMIi + TRIi for each ith SRS resource

In case of transmission using multiple SRS resources, and in case of indicating each TPMI and/or TRI for each resource, one TPMI (and/or TRI) field may be encoded in the form of concatenating multiple TPMIs (and/or TRI) for each resource, and in case of encoding size that cannot fill the entire payload size of a given field, the remaining bits may be zero-padded. In this case, the UE does not expect the total TRI value to be different from the sum of all the TRIs indicated by the ith SRS resource in the TPMI (and/or TRI) field. That is, TRI0+ TRI1+ and the like should be satisfied.

Using the above method, decoding of DCI may be performed in the following order: DMRS field- > TPMI.

As described above, in the case where the TRI is embedded in the DMRS table, an indicator of the TRI is not required. Therefore, TPMI alone is used, and for higher ranks, the number of codewords is not significantly constrained, and the overhead of DCI is reduced, and thus, the performance of higher ranks can be improved.

One of other methods for reducing DCI overhead, a method in which TRI and TPMI are jointly encoded and included in a single field may be considered, and a DMRS table (table 24 below) is interpreted by RI indicated in the field.

For example, assume that the DMRS configuration shown in table 24 is used in UL codebook-based transmission. In this case, as a port group, as represented by table 24, each of indexes 0 to 5 for rank1 (single rank) transmission, indexes 6 to 9 for rank2 transmission, index 10 for rank3 transmission, and index 11 for rank4 transmission may be used. Therefore, a maximum DMRS field bit width of 3 bits is required (this is the maximum because the index corresponding to rank1 is 6). This may have the effect of reducing the size/width by up to 1 bit compared to using the bit size/width of the existing DMRS table illustrated in table 24 below without any change, without reduction. (i.e., all 11 indices are signaled using the bit DMRS field without any change).

[ Table 24]

Indexing	DMRS port ID (+1000)	CDM group # without data	Re-indexing
				0	0	1	0
1	0	2	1
				2	1	1	2
3	1	2	3
				4	2	2	4
5	3	2	5
				6	0,1	1	0
7	0,1	2	1
				8	2,3	2	2
9	0,2	2	3
				10	0,1,2	2	0
11	0,1,2,3	2	0
				12-15	Retention	Retention	Retention

As described above, by the TRI indicated in the TRI + TPMI field, the state of the 3-bit DMRS field may be re-indexed for each rank, as represented in column 4 of table 24, and the UE may re-interpret the DMRS table (e.g., table 24) based on the indicated TRI. For example, in case that TRI 2 (rank 2) is indicated in the TRI + TPMI field and state 1 is indicated in the 3-bit DMRS field (i.e., re-index value "1" in table 24), the UE may understand/recognize that index "7" is indicated in the DMRS table of table 24. Further, the UE does not expect the UE to be indicated by a state exceeding the index range of the DMRS table, wherein the indicator is indicated in a 3-bit field or is not present. For example, in case of indicating the UE with TRI-2, the UE does not expect to indicate the UE with state 5 in the 3-bit DMRS field.

According to this embodiment, the decoding of DCI may be performed in the following order: TRI + TPMI- > DMRS field.

The following alternatives may be considered in order to design in a direction of increasing granularity of a codebook or selecting flexibility to a maximum value according to the TPMI size.

For wideband TPMI, the NR 4Tx codebook for CP-OFDM:

alternative 1: release-10 UL, there may be other entries:

alternative 2: version-15 DL, there may be other entries:

alternative 3: release-8 DL, possibly with additional entries

For example, since alternative 1 uses the UL codebook without any change, in the case of rank1, it may be considered to use the above-proposed codebook (e.g., table 19) without any change. Then, the total TPMI size becomes 5 bits and a maximum of 32 codewords can be considered for each rank.

Then, a codebook of rank2 may be defined as table 25.

[ Table 25]

Codeword indexes 0 to 15 defined in table 25 are appropriate codewords (i.e., partially coherent codewords) when performing partially coherent transmission in which four ports are paired with two ports and transmitted.

Otherwise, in case 16 codewords are added, the combinations represented in table 26 can be derived.

[ Table 26]

The codeword of codebook indices 16 through 32 is a portion of the LTE or NR DL codebook and a combined port codeword using all four ports (i.e., a fully coherent codeword), and the codeword of codebook indices 24 through 29 is a codeword that is appropriate when all four ports perform non-coherent transmission (i.e., a non-coherent codeword). In this way, in the case of configuring TRI and TPMI together, the granularity of TPMI decreases as higher ranks are entered in consideration of the total payload, but in the case of indicating TRI in a separate DMRS field, there may be an advantage that a codebook may be configured more abundantly even in higher ranks. This relates to coherent transmission of UL TX ports, more codewords are allocated to partial transmissions, etc., and this may help to increase UE performance with corresponding capabilities.

In the same manner, in the case of rank3, the codebook may be configured with table 27.

[ Table 27]

In this table, codeword indices 12 through 15 are examples of port combination codewords using all four ports, and a portion of the LTE or NR DL codebook, and the appropriate codeword (i.e., a fully coherent codeword) when the four ports are transmitted coherently. Codeword indices 16 through 19 are examples of codewords that are appropriate when all four ports are sent non-coherently (i.e., non-coherent codewords). And/or in the table, codeword indices 0 through 11 are examples of codewords that are appropriate when four ports are transmitted partially coherently (i.e., partially coherent codewords). At this time, the antenna turn-off is considered as a power scaling factor, and may also be considered, for exampleAs another scaling factor. In addition to this example, to increase the granularity of the remaining states, a portion or all of the release-8 LTE DLhouse-hold codebook may be included/used.

An example of a rank4 codebook is represented in table 28.

[ Table 28]

In this table, codeword indices 1 through 4 are examples of port combination codewords (i.e., fully coherent codewords) using all four ports, and a portion of an LTE or NR DL codebook, and four ports being transmitted coherently. In addition to this example, to increase the granularity of the remaining states, a portion or all of a release-8 LTE DL house-hold codebook may be included/used. In particular, since rank4 is the total rank transmission, and performance is not expected to improve greatly even with increased granularity. Thus, to reduce UE complexity, a certain number (e.g., 3) of codewords (e.g., 0,1, and 3 codewords) may be configured.

In case of the 4Tx codebook for CP-OFDM, the payload of TPMI may be changed due to coherent capability reporting (e.g., fully coherent, partially coherent and non-coherent) of the UE or codebook subset constraints indicated by higher layer signaling. At this time, in the case where the TRI and TPMI are jointly encoded, the payload reduction effect may correspond to the case where the sum of TPMI of each rank according to each coherence capability is reduced. In case where TRI and TPMI are separately encoded, the maximum value of the TPMI size of each rank should be reduced for payload reduction of TPMI. Therefore, it is proposed to constrain the maximum TPMI size according to each coherence capability. For example, the following examples may be considered.

1. Fully coherent-5 bits

1-1. for rank1, a codebook may be defined, as represented in table 29.

[ Table 29]

To fill 32 states in table 29 additionally, a codeword as represented in equation 33 may be additionally considered by considering 8PSK with the phase of each element.

[ equation 33]

1-2. for rank2, the codebook may be represented in table 30.

[ Table 30]

And/or, as another example, the codebook may be configured by selecting four (e.g., 24 to 27) among the codeword indexes 24 to 29 of the rank2 codebook of the above table 30. Then, the additional four states for adjustment to a size of 5 bits may be configured as shown in equation 34, or may be selected among eight states defined in equation 35.

[ equation 34]

[ equation 35]

And/or, all eight 8-PSK rank2 are used, but 12 codewords (e.g., #0 to #11 codebooks/codewords) are selected in the #0 to #15 codebooks, and a total of 32 states may be configured.

1-3. for rank3, the codebook may be represented in table 31.

[ Table 31]

And/or a portion of the codewords 20 through 27 defined in table 31 may be replaced by at least a portion of a codebook of the form shown in table 36 below.

[ equation 36]

For the rank3 codebook, when regarded as the sum of each layer (═ 0.25), it is identified that the transmission power corresponding to each antenna port is the same, and all antenna ports are transmitted through the first layer, and only a specific port group is transmitted through the second layer and the third layer, and it can be seen that it has characteristics of port selection and port combination.

1-4. for rank4, the codebook may be represented in table 32.

[ Table 32]

In the rank4 codebook, it can be explained that layer 2 transmission is performed in two panels for codewords of 4 to 7. That is, table 32 represents a codebook for layer 2 transmission of each of {1,3}, {2,4}, and may be used for the purpose of covering multi-panel codebooks.

Generally, as the layers increase, the gain obtained from the granularity of the codebook is not that large. For example, in the total rank transmission example, even in the case of using only 1 or 2 codewords, the case of rank4 transmission may show less performance to a large extent than the case of using various codebooks. Thus, in case the codebook is configured with a combination or subset of the proposed codebooks, not all configured TPMI sizes (5 bits of the present embodiment) may be used as layers increase and unused bits/states may be used for error detection. In addition, there is an advantage in that the TPMI computational complexity is reduced as the bits/states are reduced in the gbb.

2. Partial coherence 4 bits

The partially coherent codebook may be configured with at least a portion of the codewords (i.e., partially coherent (transmit) codeword, non-coherent (transmit) codeword) selected in addition to the fully coherent transmission coherence in the proposed fully coherent codebook. For example, a partially coherent codeword may be configured with codewords of indexes 16 to 27 for rank1, codewords of indexes 0 to 11 and 28 to 31 for rank2, codewords of indexes 0 to 11 and 28 to 31 for rank3, and codewords of indexes 4 to 12 for rank4 in the proposed fully coherent codebook. In this case, the maximum number of codewords is 16, and 4 bits may be allocated.

3. Non-coherent-2 bits

The non-coherent codebook may be configured with at least a portion of the proposed full (or partial) coherent codebook that is selected in addition to the full (or partial) coherent (transmission) codebook, i.e., the non-coherent (transmission) codebook. For example, the non-coherent codebook may be configured with codewords of indexes 24 to 27 for rank1, codewords of indexes 28 to 31 for rank2, codewords of indexes 28 to 31 for rank3, and codewords of index 12 for rank4 in the proposed full coherent codebook. In this case, the maximum number of codewords is 4, and 2 bits may be allocated.

That is, to summarize the above, the fully coherent codebook may be configured with a fully coherent transmission codebook, a partially coherent transmission codebook, and a non-coherent transmission codebook. The partial coherent codebook may be configured with a partial coherent transmission codebook and a non-coherent transmission codebook, and the non-coherent codebook may be configured with a non-coherent transmission codebook.

Thus, the types of UL codebooks may include a fully coherent codebook, a partially coherent codebook, and an incoherent codebook, and the UL codebook (i.e., the fully coherent codebook) may be configured with a fully coherent (transmission) codebook, a partially coherent (transmission) codebook, and an incoherent (transmission) codebook.

In this disclosure, the codeword may be referred to as a "precoding matrix".

In case that DFT-s-OFDM and CP-OFDM are configured with separate DCI formats, the proposal can be applied to DCI format configuration for CP-OFDM. In the case where DFT-s-OFDM and CP-OFDM support dynamic switching, it may be preferable that the DCI field design is a waveform-integrated design. Therefore, in case of changing CP-OFDM into DFT-s-OFDM, indications such as antenna ports, scrambling identity, and number of layers are indicatedThe field of the information may be variably interpreted in the UL-related DCI through the table 33. Table 33 maps cyclic shift fields in UL-related DCI formats toAnd [ w^(λ)(0) w^(λ)(1)]Table (ii).

[ Table 33]

In table 33, since λ is a parameter related to rank, only a column for λ ═ 0 may be applied to DFT-s-OFDM.

In the codebook, power scaling is configured by assuming that the antenna is off. That is, when the transmission power of the UE in a given power is referred to as P, the power is uniformly distributed to all ports, and the transmission power of each port is given by P/N (here, N is the number of ports), regardless of the layer. At this time, in the case of transmitting using only ports of 4 ports, the transmission power is reduced to P/4, i.e., 6dB, and a problem of coverage reduction occurs. The power division for all number of ports has an advantage in terms of Tx chain cost of the UE and has an advantage of battery saving of the UE. That is, by allowing power boosting, for the 4-port case, power transmission is performed at P/2 or P instead of P/4, there is a problem that the dynamic range of transmission power of the Tx chain should become large, which may increase cost. On the other hand, a high-end UE may be provided with a Tx chain with a large dynamic range and may report it as a capability. That is, in UL transmission, the UE may report capabilities related to whether to transmit at a certain X dB (e.g., 3dB) or less from the maximum transmission power, and this may be considered in the normalization factor determination for non-coherent transmission. For example, in the case of rank 1TPMI indices 24 to 27, the normalization factor may be set toOr 1, instead of 2, or pre-promised/defined to a particular value (e.g.,)。

in case that the proposed codebook is used for SB TPMI, the codeword used for each SB can be changed. For example, the TPMI of a particular SB may be based on a codebook using all ports (e.g., a fully coherent codebook), and another particular SB may be based on a codebook using a portion of the ports (e.g., a partially coherent codebook). In this case, when the number of ports is changed for each SB, a case occurs where UL power control becomes very complicated. Therefore, the number of ports used in the SB can be determined by WB (this can be signaled in port selection codebook format or bitmap format), and it can be proposed that the SB TPMI considers only codebooks using all the number of ports indicated by WB. That is, in describing aspects of the power scaling factor, it is assumed that the power of the TPMI using all the power P used in the total TPMI transmission is normalized to 1. The number of ports, power scaling and/or p (0< p < ═ 1) used in SB TPMI transmission is determined by a method such as WB TPMI, and SB TPMI must be normalized to a power scaling factor of 1 so as not to change the value of p.

Codebook-based transmission for the UL is supported by at least UL grant signaling as follows:

-SRI + TPMI + TRI, where TPMI is used to denote the precoder preferred by the SRS port of the SRS resource selected by SRI. When a single SRS resource is set, there may be no SRI. The TPMI is used to indicate a precoder preferred through an SRS port of the set single SRS resource.

-indication support for multiple SRS resource selection

In case of codebook-based transmission of CP-OFDM based UL, the UE is configured with UL frequency selective precoding, and in case of supporting the SB TPMI signaling method, one of the following alternatives may be supported:

-alternatively 1: the SB TPMI is signaled to the UE through DCI only for the PRBs allocated for a given PUSCH transmission.

-alternative 2: regardless of the actual RA for a given PUSCH transmission, the SB TPMI is signaled to the UE over the DCI for all PRBs of the UE.

However, other alternatives are not excluded. In the case of supporting a dual stage codebook, the SB TPMI may correspond to W2.

The WB TPMI can be signaled together with the sub-bands TPMI.

In the case of UL codebook design, one of the following two structures can be supported in NR.

-alternatively 0: single-stage codebook

-alternatively 1: two-stage codebook

In LTE, to support SC-OFDM requiring design constraints, such as maintaining PAPR and CM, a single-level UL codebook for 2-port and 4-port has been used (i.e., CM should not be increased due to multi-layer transmission). Thus, in the case of a rank greater than 1, the LTE UL codebook includes zero entries for each codeword.

However, since CP-OFDM is used for UL transmission in NR, CM maintenance constraints may not be a core design goal of the UL codebook. Furthermore, support for UL frequency selective precoding for CP-OFMD has been agreed. Therefore, as a design reference to solve the control channel overhead problem for frequency selective UL-MIMO scheduling, it is natural to consider the UL dual-stage codebook (i.e., W1W2 similar to DL).

Therefore, in the present disclosure, a two-stage codebook structure (W ═ W1W2) for UL frequency selective precoding of at least CP-OFMD can be considered.

In the dual-stage codebook, the final UL precoder W of each SB may be divided into WB PMI components W1 and corresponding SB PMI components W2. In this configuration, WB PMI component W1 may include beams/beam groups, and SB PMI component W2 may include beam selectors and/or in-phase components (e.g., for X-pol antennas). In particular, in a dual stage codebook, W1 may include DFT beam(s) whose performance is good. This is because the gNB is equipped with uniform linear (or planar) array antenna elements/panels. Unlike TRP, UE can be provided with any separate antenna element/panel and therefore low antenna correlation can be expected. For this reason, the NR UL codebook should be designed by considering the antenna arrangement and structure of the UE. This means that it should perform well for any UE antenna arrangement and structureUL codebooks. In this case, a 4Tx DL household codebook may be considered. However, for frequency selective precoding, TPMI signaling overhead may increase according to the number of configured SBs. Therefore, in order to effectively reduce the total amount of signaling overhead, a household codebook having a dual stage structure may be considered. In this design, W1 may include a set of L beams (e.g., L ═ 2,4, L is configurable), where each beam may be selected by the gNB from the household codebook. W2 can perform only requiring log per SB₂Beam selection of L bits.

That is, therefore, since the NR UL codebook should be designed to perform well for an arbitrary UE antenna arrangement and structure, a DL household codebook including beam grouping for the UL codebook may be considered.

In case the UE is provided with multiple panels, panel selection and/or combining may be considered for robust transmission for cases of fast UE rotation, blocking, etc. W1 or W2 may support this type of panel selection and/or combination functionality. In this case, the following three factors need to be considered for UL codebook design.

Number of panels supported in UL codebook

Number of ports supported per panel

Whether the UE has a different number of ports per panel

The three factors can be simplified, but the codebook structure may still be complex. Thus, SRI may be used for panel selection or antenna port group selection because antenna ports of different panels in a UE may have different average RSRP values. This means that the antenna ports of different panels can be independently supported by different resources. In summary, the UL codebook is designed by assuming a single panel, and SRI can be used for the panel selection function.

In NR, an indication of a number of SRS resource selections may be supported. In the case of multiple SRS resources, which may be indicated by the SRI field, the panel combining function may be considered. By applying an inter-panel corrector adapted to the phase and/or amplitude, the panel combination plays an important role in increasing the beamforming gain. Therefore, in case that several SRS resources are indicated for the panel combination function, an additional TPMI for the panel corrector needs to be introduced.

That is, the UL codebook may be designed by assuming a single panel, and the SRI may be used as a panel selection function. In addition, in case that several SRS resources are indicated for the panel combination function, an additional TPMI for the inter-panel phase/amplitude corrector should be introduced.

The SRI may indicate multiple choices of SRS resources that may support multiple panel joint transmissions in the UL. In addition, each panel transmission associated with each indicated SRS resource may be directed to a different UL reception point in the UL-CoMP context. To support correctly, the NR network should compute at least an accurate MCS for each different layer group corresponding to different SRS resources by using a separate power control procedure for each SRS resource. Typically, multiple ULPC procedures need to be supported for a UE, and each ULPC procedure may be associated with at least one SRS resource configured for the UE. For example, configured SRS resource IDs #1 and #2 may be associated with the same ULPC process a, and other configured SRS resource IDs #3 may be associated with different ULPC processes B. ULPC procedures a and B may be oriented to different reception points, and SRS resources #1 and #2 following the same ULPC procedure a may be dynamically selected by SRI indication agreed in UL grant. For example, in the case where SRS resources #1 (including corresponding TPMI/TRI) and #3 (including corresponding TPMI/TRI) are collectively indicated by the SRI field in the UL grant, this may be interpreted as UL-CoMP joint reception operation in UL multi-panel transmission and a gNB distinguished as a layer group.

In NR, in order to apply frequency selective precoding for UL-MIMO, control channel overhead increased due to SB PMI indication may be a serious problem. To solve this problem, the 2-level DCI may be considered as one of the alternatives, and the advantages and disadvantages may be different according to the detailed factors of the 2-level DCI. Regarding the latency issue, the DCI decoding failure issue and the DCI overhead, three types of 2-level DCI can be discussed one after another as follows.

Option 1:

-a first DCI: UL grants, e.g. LTE DCI 0/4

-a second DCI: SB PMI for allocated RBs

-DCI transmission timing: the 2 DCIs are transmitted at the same subframe.

Option 2:

-a first DCI: SB PMI of all RBs

-a second DCI: UL grants, e.g. LTE DCI 0/4

-DCI transmission timing: one or more second DCIs that reference the first DCI are transmitted on/after the first DCI transmission subframe.

With respect to channel aging issues, option 2 may not be desirable because UL grant information may be delivered after several subframes of later SB PMI delivery. The motivation for introducing such a frequency selective UL precoder is also to achieve accurate UL link adaptation with the frequency domain, so that it is desirable to deliver the full set of scheduling information to the UE instantaneously when scheduling for UL transmission. For option 1, there is no delay issue because 2 DCIs are transmitted on the same subframe.

For all options, the complete information on UL scheduling is divided into two DCIs, so the UE seems to be unable to transmit UL data without being able to decode one of the two DCIs. For option 2, in case the UE fails to decode the first DCI, several second DCIs referring to the first DCI may be wasted. To address this issue, an appropriate mechanism for reporting the decoding result of the first DCI to the gNB may be required.

In terms of DCI overhead, these two options help to reduce overhead. For option 1, SB PMI is indicated for only scheduled SBs and not for all SBs by the second DCI, so that the second DCI payload size is adaptively reduced in case a small RB is allocated to the UE. For option 2, SB PMIs for all SBs should be indicated by the first DCI, since the second DCI including UL grant may be signaled after the first DCI transmission. In this design, overhead savings may be realized in a temporal manner. In other words, the first DCI is transmitted only once for a plurality of UL grants, thereby saving DCI overhead.

Another option is the following single-stage DCI:

option 3:

-a single DCI: SB PMI for allocated RBs and UL grant as LTE DCI 0/4

Option 4:

-a single DCI: SB PMI for all RBs, and UL grant as LTE DCI 0/4

In options 3 and 4, there is no channel aging or decoding failure problem with level 2 DCIs, but it may require more payload to be included in a single DCI. Even in option 3, it is expected to maintain the same payload size regardless of the allocated RB size so as not to increase DCI BD overhead. As a result, the DCI size of option 3 is determined based on the case where the allocated RB is a wideband and the DCI sizes of options 3 and 4 are the same.

To minimize DCI overhead, compression for SB PMI indication is critical. To solve the control channel overhead problem of frequency selective UL-MIMO scheduling, a compression method for SB PMI payload should be studied together with a codebook structure. In a dual codebook structure, the final UL precoder W for each subband may be decomposed into wideband PMI component W1 and corresponding subband PMI component W2. Then, the UL scheduling DCI contains one wideband W1 and multiple SB W2. To reduce the payload size of SB W2, codebook subsampling may be considered. In the case of a single codebook structure like the release-8 LTE codebook, the SB PMI payload can also be compressed in a similar manner. More specifically, a codebook subset for the SB PMI is constrained based on the WB PMI in such a way that the subset includes a highly correlated PMI with the WB PMI.

UL DCI design for frequency selective scheduling should be studied according to delay issues, DCI decoding failure issues, and DCI overhead. In addition, to reduce DCI overhead, the SB PMI should be indicated from a subset of the entire codebook.

Fig. 17 is a flowchart illustrating a PUSCH transmission operation of a UE according to an embodiment of the present invention. With respect to this flowchart, the above description/embodiment may be applied identically/similarly, and a duplicate description will be omitted.

First, the UE may receive DCI for UL transmission scheduling (step S1710). At this time, the DCI may include TPMI as precoding information, which is information of an index of a precoding matrix selected for PUSCH transmission of the UE. Furthermore, the DCI may further include an RI, which is information of a layer for PUSCH transmission of the UE, and in this case, the RI may be jointly encoded with the TPMI and included in the DCI. In addition, in order to determine DMRS ports, the size of a predefined DMRS field/table (in DCI) may be differently determined according to RI jointly encoded with TPMI. That is, DMRS fields/tables may be differently encoded/decoded/interpreted/defined/configured based on/according to RI.

As an embodiment, TPMI is indicated for each SRS resource configured to the UE, and RI may be indicated in common for the configured SRS resources. Alternatively, as another example, the TPMI and RI may be indicated collectively for all SRS resources configured to the UE. Alternatively, another embodiment, TPMI, and RI may be indicated for each SRS resource configured to the UE.

Next, the UE may perform codebook-based PUSCH transmission based on the precoding information (step S1720). At this time, in case of transmitting PUSCH using four antenna ports, the codebook may include a first group including a non-coherent precoding matrix for selecting only one port of each layer; a second group including a non-coherent precoding matrix for selecting only one port for each layer; and/or a third group comprising a full-phase intervening encoding matrix for selecting all ports of each layer. Here, the non-coherent precoding matrix may represent a matrix including one vector having a non-zero value in each column, the partially coherent precoding matrix may represent a matrix including two vectors having a non-zero value in at least one column, and the all-phase interference encoding matrix may represent a matrix including only vectors having a non-zero value. In addition, the codebook may be a codebook based on a CP-OFDM waveform.

In addition, although not shown in the flowchart, the UE may receive constraint information of the number of layers used in PUSCH transmission. For example, the UE may receive constraint information of the maximum number of layers available in the PUSCH transmission from the gNB through higher layer signaling (e.g., RRC). In this case, the UE does not use the codebook corresponding to the constrained layer in the PUSCH transmission. In addition, the size of the field in which the TPMI and the RI are jointly encoded is determined based on the constraint information of the number of layers.

In addition, although not shown in the flowchart, the UE may receive constraint information of a precoding matrix available in PUSCH transmission in a codebook. At this time, constraint information of the precoding matrix may be signaled/generated to indicate a precoding matrix available in PUSCH transmission in a group (e.g., first to third group) unit or a separate precoding matrix unit. The size of the field in which the TPMI and RI are jointly encoded is determined based on constraint information of the precoding matrix. That is, fields/tables for joint coding of TPMI and RI may be differently encoded/decoded/interpreted/defined/configured based on/according to constraint information of precoding matrix.

Universal device to which the invention can be applied

Referring to fig. 18, the wireless communication system includes a Base Station (BS) (or eNB)1810 and a plurality of terminals (or UEs) 1820 located within a coverage of the eNB 1810.

The eNB 1810 includes a processor 1811, a memory 1812, and a Radio Frequency (RF) unit 1813. The processor 1811 implements the functions, processes, and/or methods set forth above. Layers of a radio interface protocol may be implemented by the processor 1811. A memory 1812 may be connected to the processor 1811 to store various types of information for driving the processor 1811. The RF unit 1813 may be connected to the processor 1811 to transmit and/or receive a wireless signal.

The UE 1820 includes a processor 1821, a memory 1822, and a Radio Frequency (RF) unit 1823. The processor 1821 implements the functions, procedures, and/or methods set forth above. Layers of the radio interface protocol may be implemented by the processor 1821. A memory 1822 may be connected to the processor 1821 to store various types of information for driving the processor 1821. The RF unit 1823 may be connected to the processor 1821 to transmit and/or receive wireless signals.

The memory 1812 or 1822 may exist within or outside of the processor 1811 or 1821 and may be connected to the processor 1811 or 1821 by various well-known units. Also, the eNB 1810 and/or the UE 1820 may have a single antenna or multiple antennas.

In particular, fig. 19 shows an example of an RF module that may be implemented in a Frequency Division Duplex (FDD) system.

First, in the transmit path, the processor processes the data to be transmitted and provides an analog output signal to the transmitter 1910.

Within transmitter 1910, the analog output signal is filtered by a Low Pass Filter (LPF)1911 to remove undesired images caused by previous digital-to-analog conversion (ADC), upconverted from baseband to RF by an upconverter (mixer) 1912 and amplified by a Variable Gain Amplifier (VGA) 1913, and the amplified signal is filtered by a filter 1914, further amplified by a Power Amplifier (PA)1915, routed through a duplexer 1950/antenna switch 1960, and transmitted via an antenna 1970.

Additionally, in the receive path, an antenna 1970 receives signals from the outside and provides a received signal, which is routed through antenna switch 1960/duplexer 1950 and provided to a receiver 1920.

Within receiver 1920, the received signal is amplified by a Low Noise Amplifier (LNA)1923, filtered by a bandpass filter 1924, and downconverted from RF to baseband by a downconverter (mixer) 1925.

The downconverted signal is filtered by a Low Pass Filter (LPF)1926 and amplified by a VGA 1927 to obtain an analog input signal, which is provided to the processor.

In addition, a Local Oscillator (LO) generator 1940 generates and provides transmit and receive LO signals to upconverter 1912 and downconverter 1925, respectively.

In addition, a Phase Locked Loop (PLL)1930 may receive control information from the processor and provide control signals to LO generator 1940 to generate transmit and receive LO signals at the appropriate frequencies.

The circuit shown in fig. 19 may be arranged differently from the configuration shown in fig. 19.

In particular, fig. 20 shows an example of an RF module that may be implemented in a Time Division Duplex (TDD) system.

The transmitter 2010 and the receiver 2031 of the RF module in the TDD system have the same structure as those of the RF module in the FDD system.

Hereinafter, only the structure of the RF module of the TDD system, which is different from that of the FDD system, is described, and the same structure is described with reference to fig. 10.

A signal amplified by a Power Amplifier (PA)2015 of the transmitter is routed through a band selection switch 2050, a Band Pass Filter (BPF)2060, and an antenna switch 2070, and transmitted via an antenna 2080.

Also in the receive path, an antenna 2080 receives signals from the outside and provides a received signal, which is routed through an antenna switch 2070, a Band Pass Filter (BPF)2060, and a band select switch 2050 and provided to the receiver 2020.

The foregoing embodiments are achieved by combining structural elements and features of the present invention in a predetermined manner. Each structural element or feature should be selectively considered unless individually specified. Each structural element or feature may be executed without being combined with other structural elements or features. In addition, some structural elements and/or features may be combined with each other to construct an embodiment of the present invention. The order of operations described in the embodiments of the present invention may be changed. Some structural elements or features of one embodiment may be included in another embodiment or may be replaced with corresponding structural elements or features of another embodiment. Further, it is apparent that some claims referring to specific claims may be combined with other claims referring to other claims other than the specific claims configuring the embodiment or new claims may be added by modification after filing the application.

In the present disclosure, "a and/or B" may be interpreted to mean at least one of a and/or B.

Embodiments of the invention may be implemented by various means, such as hardware, firmware, software, or a combination thereof. In a hardware configuration, the method according to an embodiment of the present invention may be implemented by one or more ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), processors, controllers, micro-controllers, microprocessors, and the like.

In a firmware or software configuration, embodiments of the present invention may be implemented in the form of modules, procedures, functions, and the like. The software codes may be stored in a memory and executed by a processor. The memory may be located inside or outside the processor, and may transmit and receive data to and from the processor by various known means.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Modes for carrying out the invention

Various forms for embodiments of the invention have been described in the best mode of the invention.

INDUSTRIAL APPLICABILITY

The present invention applied to the 3GPP LTE/LTE-a/5G system is mainly described as an example, but may be applied to various wireless communication systems in addition to the 3GPP LTE/LTE-a/5G system.

Claims

1. A method performed by a User Equipment (UE) for transmitting a codebook-based Physical Uplink Shared Channel (PUSCH) in a wireless communication system, comprising:

receiving Downlink Control Information (DCI) for Uplink (UL) transmission scheduling; and

performing codebook-based PUSCH transmission based on precoding information included in the DCI,

wherein, when the PUSCH is transmitted using four antenna ports, the codebook includes:

a first group including a non-coherent precoding matrix for selecting only one port of each layer;

a second group comprising a partially coherent precoding matrix for selecting two ports in at least one layer; and

and a third group comprising a fully coherent encoding matrix for selecting all ports of each layer.

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein the non-coherent precoding matrix is a matrix comprising one vector with non-zero values in each column,

wherein the partially coherent precoding matrix is a matrix including two vectors having non-zero values in at least one column, and

wherein the full-phase intervention coding matrix is a matrix comprising only vectors with non-zero values.

3. The method of claim 2, wherein the codebook is a codebook based on a cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) waveform.

4. The method of claim 2, wherein the DCI includes a Transmitted Precoding Matrix Indicator (TPMI), which is information that is an index of a precoding matrix the precoding information is selected for the PUSCH transmission.

5. The method of claim 4, wherein the TPMI is jointly encoded with a Rank Indicator (RI), which is information of a layer used in the PUSCH transmission.

6. The method of claim 5, wherein the first and second light sources are selected from the group consisting of,

wherein the TPMI is indicated for each Sounding Reference Signal (SRS) resource configured to the UE, and

wherein the RI is indicated in common for the configured SRS resources.

7. The method of claim 5, wherein the TPMI and the RI are indicated collectively for all SRS resources configured to the UE.

8. The method of claim 5, wherein the TPMI and the RI are indicated for each SRS resource configured to the UE.

9. The method of claim 5, wherein a predefined DMRS (demodulation RS) field in the DCI is differently sized to determine DMRS ports according to the RI jointly encoded with the TPMI.

10. The method of claim 9, further comprising: receiving constraint information of a number of layers available in the PUSCH transmission.

11. The method of claim 9, wherein a size of a field in which the TPMI and the RI are jointly encoded is decided based on constraint information of the number of layers.

12. The method of claim 5, further comprising: receiving constraint information of precoding matrices available in the PUSCH transmission in the codebook.

13. The method according to claim 12, wherein the constraint information of the precoding matrix indicates the precoding matrix available in the PUSCH transmission in group units or individual precoding matrix units.

14. The method of claim 12, wherein a size of a field in which the TPMI and the RI are jointly encoded is decided based on constraint information of the precoding matrix.

15. A User Equipment (UE) for transmitting a codebook-based Physical Uplink Shared Channel (PUSCH) in a wireless communication system, comprising:

a Radio Frequency (RF) unit for transmitting and receiving a radio signal; and

a processor for controlling the RF unit,

wherein the processor is configured to perform:

receiving Downlink Control Information (DCI) for Uplink (UL) transmission scheduling; and is

when the PUSCH is transmitted using four antenna ports, the codebook includes: