KR20240053499A - Wireless communication device for compression of channel state information(csi) and method of operation thereof - Google Patents

Abstract

A method of operating a wireless communication device according to an aspect of the technical idea of the present disclosure, comprising: receiving a channel state information reference signal (CSI-RS) from a base station; generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; And reporting the channel information to the base station, wherein the step of generating the channel information includes: performing first compression by compressing channel characteristic information of the subband on which the CSI-RS is received in the spatial domain. generating data; Using a first discrete Fourier transform (DFT) function of a size corresponding to the number of subbands on which the CSI-RS was received among the bandwidth parts (BWP) for communication with the base station, the first compressed data Compressing in the frequency domain to generate second compressed data; And it may include generating the channel information based on the second compressed data.

Description

Wireless communication device for compression of channel information and method of operation thereof {WIRELESS COMMUNICATION DEVICE FOR COMPRESSION OF CHANNEL STATE INFORMATION (CSI) AND METHOD OF OPERATION THEREOF}

The technical idea of the present disclosure relates to an apparatus for compressing channel state information in a wireless communication system and a method of operating the same.

Recently, wireless communication devices use eTypeII (Enhanced TypeII) codebook to reduce the overhead of Channel State Information (CSI) feedback based on 3GPP communication standards (e.g. Rel.16). You can communicate with the base station using . The eTypeII (Enhanced TypeII) codebook achieves the requirements for overhead reduction by feeding back channel information by utilizing the correlation characteristics between the space and frequency of channel information. In more detail, the process goes through below. 1) The base station transmits CSI-RS (channel state information-resource signal) to the wireless communication device using the antenna port and time/frequency resource element (RE) defined in the standard. 2) The wireless communication device estimates the multiple-input multiple-output (MIMO) channel between the base station and the wireless communication device from the received CSI-RS signal and then generates channel information to report to the base station. 2) In the channel information generation process, the wireless communication device determines the precoding (or beamforming) of the base station. At this time, the spatial domain of the base station's precoding is determined by using the eTypeII codebook. /A compression process of channel information is performed taking into account frequency domain characteristics. A wireless communication device has the advantage of being able to transmit channel information with relatively few wireless communication resources (e.g., time/frequency RE) through a compression process of channel information. The spatial domain characteristics of the base station's precoding are based on the basis having the dominant value among the basis of the spatial domain, in which the values corresponding to the antenna ports are re-expressed in an oversampled DFT (Discrete Fourier Transform) space. Choose. The frequency domain characteristic of the base station's precoding selects a dominant basis among the basis of the frequency domain in which values corresponding to frequencies of channel information are re-expressed in DFT space. Only the base station's precoding values re-expressed in a small-dimensional space determined through a compression process of channel information that selects the space/frequency dimension with the basis of the selected space/frequency domain are reported to the base station.

Accordingly, there is a need for a wireless communication device that performs space/frequency domain compression in consideration of the space/frequency domain characteristics of the base station's precoding in the channel information compression process and minimizes the loss of channel information in the compression process.

The problem that the technical idea of the present disclosure seeks to solve is that, in a wireless communication system, when CSI-RS is transmitted in some subbands of the entire BWP (bandwidth part), channel information based on information about the subband on which the CSI-RS was received The goal is to reduce the overhead of CSI reporting through compression and provide a terminal device that performs efficient CSI feedback.

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

In order to achieve the above object, a method of operating a wireless communication device according to an aspect of the present disclosure includes the steps of receiving a channel state information reference signal (CSI-RS) from a base station; generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; And reporting the channel information to the base station, wherein the step of generating the channel information includes: performing first compression by compressing channel characteristic information of the subband on which the CSI-RS is received in the spatial domain. generating data; Using a first discrete Fourier transform (DFT) function of a size corresponding to the number of subbands on which the CSI-RS was received among the bandwidth parts (BWP) for communication with the base station, the first compressed data Compressing in the frequency domain to generate second compressed data; And it may include generating the channel information based on the second compressed data.

In order to achieve the above object, a method of operating a wireless communication device according to an aspect of the present disclosure includes the steps of receiving a channel state information reference signal (CSI-RS) from a base station; generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; And reporting the channel information to the base station, wherein the step of generating the channel information includes: performing first compression by compressing channel characteristic information of the subband on which the CSI-RS is received in the spatial domain. generating data; A first part DFT (partial discrete fourier) consisting of a column domain corresponding to a subband constituting a bandwidth part (BWP) for communication with the base station and a row domain corresponding to the subband on which the CSI-RS was received. generating second compressed data by compressing the first compressed data in the frequency domain using a transform) function; and generating the channel information based on the second compressed data.

In order to achieve the above object, a method of operating a wireless communication device according to an aspect of the present disclosure includes the steps of receiving a channel state information reference signal (CSI-RS) from a base station; generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; And reporting the channel information to the base station, wherein the step of generating the channel information includes: performing first compression by compressing channel characteristic information of the subband on which the CSI-RS is received in the spatial domain. generating data; Performing preprocessing according to a predetermined method on a subband in which the CSI-RS is not received among the bandwidth part (BWP) for communication with the base station in the first compressed data; Compressing the preprocessed first compressed data in the frequency domain using a discrete Fourier transform (DFT) function of a size corresponding to the number of subbands constituting the BWP to generate second compressed data; And it may include generating the channel information based on the second compressed data.

When CSI-RS is received in some subbands of the entire BWP through the compression process of channel information in the frequency domain according to the technical idea of the present disclosure, by performing CSI reporting for some subbands on which the CSI-RS was received, It is possible to provide a wireless communication device that prevents excessive overhead for CSI reporting and adaptively compresses and reports channel information according to the received subband of CSI-RS. In addition, a wireless communication device capable of preventing modification and contamination (or distortion) of CSI report content due to interference between channels can be provided through a compression process of channel information in the frequency domain according to the technical idea of the present disclosure.

The effects that can be obtained from the exemplary embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned are common knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. It can be clearly derived and understood by those who have it. That is, unintended effects resulting from implementing the exemplary embodiments of the present disclosure may also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

1 illustrates an example wireless communication system according to an exemplary embodiment of the present disclosure.
Figure 2 is a block diagram showing a wireless communication device according to an exemplary embodiment of the present disclosure.
FIG. 3 is a block diagram for explaining a specific implementation example of the first RFIC and first antenna module of FIG. 2.
Figure 4 is a block diagram of a channel information compression circuit according to an exemplary embodiment of the present disclosure.
Figure 5 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.
6A and 6B are diagrams for explaining an FD compression operation by a first sub-transform block according to an exemplary embodiment of the present disclosure.
Figure 7 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.
8A to 8E are diagrams for explaining an FD compression operation by a second sub-transform block according to an exemplary embodiment of the present disclosure.
Figure 9 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.
10A to 10D are diagrams for explaining an FD compression operation by a third sub-transform block according to an exemplary embodiment of the present disclosure.
Figure 11 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.
12A to 12G are diagrams for explaining an FD compression operation by a fourth sub-transform block according to an exemplary embodiment of the present disclosure.
Figure 13 is a block diagram showing an electronic device according to an exemplary embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

For convenience of explanation, the present invention uses some of the terms and names defined in the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) standard or the NR (New Radio) standard. However, the present invention is not limited by the above terms and names, and can be equally applied to systems complying with other standards.

An entity that communicates with a wireless communication device according to an embodiment of the present disclosure and allocates communication network resources to the wireless communication device, including a cell, base station (BS), NodeB (NB), eNodB (eNB), and NG. It may be at least one of a next generation radio access network (RAN), a radio access unit, a base station controller, a node on the network, and a gnodeB (gNB).

A wireless communication device is an entity that communicates with a base station or other wireless communication devices, and includes a node, user equipment (UE), next generation UE (NG UE), mobile station (MS), mobile equipment (ME), It may be at least one of a device and a terminal.

Additionally, wireless communication devices include smartphones, tablet PCs, mobile phones, video phones, e-book readers, desktop PCs, laptop PCs, netbook computers, PDAs, portable multimedia players (PMPs), MP3 players, medical devices, cameras, or wearables. It may include at least one of the devices. In addition, wireless communication devices include televisions, DVD (digital video disk) players, audio systems, refrigerators, air conditioners, vacuum cleaners, ovens, microwave ovens, washing machines, air purifiers, set-top boxes, home automation control panels, security control panels, and media boxes. It may include at least one of (e.g. Samsung HomeSyncTM, Apple TVTM, or Google TVTM), a game console (e.g. XboxTM, PlayStationTM), an electronic dictionary, an electronic key, a camcorder, or an electronic picture frame. In addition, wireless communication devices may be used in various medical devices (e.g., various portable medical measurement devices (blood sugar monitor, heart rate monitor, blood pressure monitor, or body temperature monitor, etc.), magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography (CT), etc. tomography, radiography, or ultrasound, etc.), navigation devices, global navigation satellite system (GNSS), event data recorder (EDR), flight data recorder (FDR), automotive infotainment devices, marine electronic equipment (e.g. marine navigation systems, gyro compasses, etc.), avionics, security devices, head units for vehicles, industrial or domestic robots, drones, ATMs at financial institutions, point of sales (POS) at stores. , or it may include at least one of IoT devices (e.g., light bulbs, various sensors, sprinkler devices, fire alarms, thermostats, street lights, toasters, exercise equipment, hot water tanks, heaters, boilers, etc.). In addition, the wireless communication device may include various types of multi-media systems capable of performing communication functions.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

1 illustrates an example wireless communication system according to an exemplary embodiment of the present disclosure.

Referring to FIG. 1, a wireless communication system 10 may include a base station 200 and a wireless communication device 100. In FIG. 1, for convenience of explanation, the wireless communication system 10 is shown as including only one base station 200 and one wireless communication device 100, but this is only an exemplary embodiment and is not limited thereto, and various Wireless communication system 10 may be implemented to include any number of base stations and wireless communication devices.

The base station 200 is connected to the wireless communication device 100 through a wireless channel and can provide various communication services. The base station 200 can provide services through a shared channel for all user traffic, and performs scheduling by collecting status information such as buffer status, available transmission power status, and channel status of the wireless communication device 100. can do. The wireless communication system 10 can support beam forming technology using Orthogonal Frequency Division Multiplexing (OFDM) as a wireless access technology. In addition, the wireless communication system 10 uses an adaptive modulation & coding (AMC) method that determines the modulation scheme and channel coding rate according to the channel status of the wireless communication device 100. can support.

Additionally, the wireless communication system 10 can transmit and receive signals using a wide frequency band existing in a frequency band of 6 GHz or higher. For example, the wireless communication system 10 can increase the data transmission rate by using a millimeter wave band, such as the 28 GHz band or the 60 GHz band. At this time, because the millimeter wave band has a relatively large signal attenuation per distance, the wireless communication system 10 can support transmission and reception based on a directional beam generated using multiple antennas to secure coverage. The wireless communication system 10 may be a system that supports Multiple Input, Multiple Output (MIMO), and accordingly, the base station 200 and the wireless communication device 100 may support beam forming technology. Beam forming technology can be divided into digital beam forming, analog beam forming, hybrid beam forming, etc., and hereinafter, the wireless communication system will describe the idea of the present technology focusing on embodiments that support the hybrid beam forming technology, but this technology It will be fully understood that it can be applied to other beam forming technologies as well.

Referring to FIG. 1, the base station 200 may transmit a channel state information-reference signal (CSI-RS) to the wireless communication device 100. The wireless communication device 100 can estimate the downlink channel using CSI-RS.

The wireless communication device 100 can utilize channel information compression technology (e.g., space domain/frequency domain compression technology) to accurately transmit channel state information to the base station using small uplink resources. there is. As an example, the wireless communication device 100 generates first compressed data through space domain compression based on the subband that received the CSI-RS, and frequency domain compression using various DFT functions on the first compressed data. The second compressed data can be generated by performing . The wireless communication device 100 may transmit channel information (eg, CSI report) generated based on the second compressed data to the base station 200.

This disclosure proposes a method for maximizing compression performance of channel information by proposing a method for reporting channel information through frequency domain compression technology based on various DFT functions.

Figure 2 is a block diagram showing a wireless communication device according to an exemplary embodiment of the present disclosure.

In detail, FIG. 2 may show a block diagram within a modem chip of the wireless communication device 100 of FIG. 1.

Referring to FIG. 2, the wireless communication device 100 of FIG. 1 includes a baseband processor 110, a first RF integrated circuit (hereinafter referred to as a Radio Frequency Integrated Circuit (RFIC)) 120, and first to i It may include antenna modules 130_1 to 130_i, a second RFIC 140, a plurality of antennas 150, and a memory 160.

The baseband processor 110 may control overall operations of the wireless communication device 100. For example, the baseband processor 110 may include a channel quality measurement circuit 112, a switching control circuit 114, and a channel state information (CSI) (hereinafter referred to as CSI) compression circuit 116. You can.

The channel quality measurement circuit 112, switching control circuit 114, and CSI compression circuit 116 may be implemented as hardware or may be software. The operations of the channel quality measurement circuit 112, switching control circuit 114, and CSI compression circuit 116, which will be described below, may be understood as the operation of the baseband processor 110.

The channel quality measurement circuit 112 uses first to ith antenna modules 130_1 to identify whether the channel of the main component carrier among the plurality of component carriers is deteriorated when communicating with the base station 200 or another device. The channel quality of ~130_i) can be measured.

The channel quality measurement circuit 112 can measure the states of a channel receiving a signal through each of the first to i antenna modules 130_1 to 130_i, and measures the states of the channel receiving the signal based on the measured channel state. Indicators indicating the channel status for each of the plurality of component carriers corresponding to the modules 130_1 to 130_i may be generated.

For example, the channel quality measurement circuit 112 includes a rank indicator (RI), channel quality indicator (CQI), reference signal received power (RSRP), reference signal received quality (RSRQ), and SINR for the channel status of the received signals. At least one of (Signal to Interference plus Noise Ratio), RSSI (Received Signal Strength Indicator), correlation related to the reference signal, or variable gain index can be measured.

The switching control circuit 114 switches between the first to i antenna modules 130_1 to 130_i and the first RFIC 120 based on the layer allocation information received to perform communication with the base station 200 device or other devices. You can control the connection. The first RFIC 120 may include first to kth RF chains (121_1 to 121_k) corresponding to RF resources. Each of the first to ith antenna modules 130_1 to 130_i may include the first to mth antenna arrays 130_11 to 130_1m. Each of the first to mth antenna arrays 130_11 to 130_1m may include first to nth phase front-ends 131_11 to 131_1n and first to nth antennas 132_11 to 132_1n. The switching control circuit 114 controls the first to k-th RF chains (121_1 to 121_k) and the first to i-th antenna modules (130_1 to 130_i) in accordance with the layer allocation information received from the base station 200 device. The connection between the to mth antenna arrays (130_11 to 130_1m) can be controlled.

The switching control circuit 114 may control the connection between the selected antenna module and the first RFIC 120 based on layer allocation information received from the base station 200 device. For example, the switching control circuit 114 disconnects the selected antenna module and the first RFIC 120 based on layer allocation information received from the base station 200 device and connects the other antenna module and the first RFIC ( Antenna module switching operation can be performed by controlling the connection of 120).

For example, the first RFIC 140 may support communication in a millimeter wave band, and the second RFIC 140 may support communication in a frequency band lower than the millimeter wave band. The second RFIC 140 may be selectively connected to a plurality of antennas 150.

The CSI compression circuit 116 performs spatial domain compression and frequency domain compression based on a reference signal (e.g., channel information reference signal (CSI-RS)) received from the base station 200 and reports channel information (CSR-RS reporting). ) can create channel information for. The generated channel information may be stored in an uplink control information (UCI) bit sequence and reported to the base station 200.

The memory 160 may store indicators of the first to ith antenna modules 130_1 to 130_i. The memory 160 may store information necessary for connection control between the first RFIC 140 and the first to ith antenna modules 130_1 to 130_i. In some embodiments, the channel quality measurement circuit 112 and switching control circuit 114 may be implemented as software and stored in memory 160 in code form. Switching history information may also be stored in memory 160.

For example, the memory 160 may be implemented as a volatile memory such as SRAM (Static Random Access Memory). In some embodiments, the memory 160 is volatile memory, such as Dynamic Random Access Memory (DRAM), or non-volatile memory, such as ROM, Flash memory, Resistive Random Access Memory (ReRAM), or Magnetic Random Access Memory (MRAM). It can also be implemented in memory.

However, the implementation of the wireless communication device 100 shown in FIG. 2 is only an exemplary embodiment, and is not limited thereto, and various implementations suitable for performing operations based on the technical idea of the present disclosure may be applied. .

FIG. 3 is a block diagram for explaining a specific implementation example of the first RFIC and first antenna module of FIG. 2.

In detail, FIG. 3 shows a first RFIC and a first antenna module of the wireless communication device 100, and the wireless communication device 100 of FIG. 2 is a channel compressed in the spatial domain/frequency domain by the CSI compression circuit 116. Information may be reported (or transmitted) to the base station through the first RFIC (120a) and the first antenna module (130_1a).

Referring to FIG. 3, the first RFIC (120a) of the wireless communication device 100 of FIG. 1 may include first to kth RF chains (121_1a to 121_ka) and a switch interface (122a). The implementation example of the first antenna module 130_1a described in FIG. 3 may also be applied to the second to ith antenna modules 130_2 to 130_i of FIG. 2. For example, in the initial stage of access between the base station 200 and the wireless communication device 100 in a wireless communication system, the first to kth RF chains 121_1a to 121_ka are connected based on layer allocation information set by the base station 200. It is possible to control the connection between and the first antenna module (130_1a).

For example, in a wireless communication system, when the channel state of the main component carrier is deteriorated, the switch interface 122a configures the first to kth RF chains 121_1a to 121_ka based on the changed layer allocation information received from the base station 200. ) and the first antenna module (130_1a) can be controlled.

Each of the first to kth RF chains (121_1a to 121_ka) may include an analog-to-digital converter (ADC), a mixer (MX), and a variable gain amplifier (VGA). The variable gain amplifier (VGA) amplifies the received signal based on variable gain, the mixer (MX) can frequency down-convert the amplified signal based on the frequency signal (LO), and the analog-to-digital converter (ADC) can convert the converted signal into a digital signal. A digital signal output from an analog-to-digital converter (ADC) may be provided to the baseband processor 110 of FIG. 2.

The analog-to-digital converter (ADC), mixer (MX), and variable gain amplifier (VGA) form the path of the signal received by the wireless communication device 100, and correspond to the first to kth RF chains 121_1a ~ of FIG. 3. 121_ka) may further include components that form a path for a signal transmitted by the wireless communication device 100. The switch interface 122a may connect the first to kth RF chains 121_1a to 121_ka and the first antenna module 130_1a in response to the switch control signal.

The first antenna module 130_1a may include first to mth antenna arrays 130_11a to 130_1ma and first to mth combiners 133_1a to 133_ma. An implementation example of the first antenna array 130_11a may be applied to the second to mth antenna arrays 130_12a to 130_1ma. Each of the first to mth antenna arrays 130_11a to 130_1ma may include first to nth phase front-ends 131_11a to 131_1na and first to mth antennas 132_11a to 132_ma connected thereto. Each of the first to nth phase front-ends 131_11a to 131_1na may include a phase shifter (PS) and a low noise amplifier (LNA). A plurality of reception beam patterns may be formed in the first antenna module 130_1a through phase adjustment of the plurality of phase shifters PS included in the first antenna module 130_1a. The first to mth combiners 133_1a may combine signals received from the first to mth antenna arrays 130_11a to 130_1ma respectively connected and output the sum to the first RFIC 120a.

The implementation of the first RFIC 120a and the first antenna module 130_1a in FIG. 3 is merely an exemplary embodiment, and is not limited thereto, and various implementations suitable for communication in the millimeter wave band may be applied.

Figure 4 is a block diagram of a channel information compression circuit according to an exemplary embodiment of the present disclosure.

In detail, FIG. 4 shows the space domain compression process and the frequency domain compression process of the baseband processor 110 of FIG. 2 (in particular, the channel information (CSI) compression circuit 116 (hereinafter referred to as the CSI compression circuit)). This is a block diagram for explanation.

Referring to FIG. 4, the CSI compression circuit 116 includes a spatial domain (SD) compression block 410 (hereinafter referred to as an SD compression block) and a frequency domain (FD) compression block 420 ( Hereinafter referred to as an FD compression block), it may include a non-zero coefficients (NZC) selection and Uplink Channel Information (UCI) bit sequence generation block 430.

The SD compression block 410 may perform spatial domain compression based on the received CSI-RS using a spatial codebook according to the spatial domain characteristics of the subband on which the CSI-RS was received. For example, the SD compression block 410 re-expresses the values corresponding to the antenna ports of the base station in an oversampled DFT (Discrete Fourier Transform) space and then re-expresses the dominant value among the basis (e.g., column vector). You can select the SD basis with .

The FD compression block 420 includes a DFT transform block 421, an FD basis selection block 426, and an NZC selection and quantization block 427 and a bypass path 428 (e.g., the bypass path 428 is a CSI -Number of subbands in which RS was received ( ) vs. BWP( ) may be used when the ratio of the number of subbands constituting the subband is an integer.) may be included.

The DFT transform block 421 may include a first sub-transform block 421, a second sub-transform block 422, a third sub-transform block 423, and a fourth sub-transform block 424. When CSI-RS is received in some subbands of the entire BWP for communication between a base station and a wireless communication device, the DFT transform block 421 according to an embodiment of the present disclosure converts the first sub transform block 421 and the second sub Frequency domain compression may be performed using any one of the transform block 422, the third sub-transform block 423, or the fourth sub-transform block 424. When CSI-RS is received in the entire BWP, frequency domain compression can be performed using a DFT function (e.g., a DFT function defined in 3GPP Rel. 16 or 17) that corresponds to the entire BWP size, although not shown in FIG. 4. there is.

In one embodiment, the matrix corresponding to the nth subband of the SD compressed first compressed data is It is defined as, where L means the number of dimensions reduced by SD compression, and Rank may mean the total number of layers for multiple input/output (MIMO) communication between the base station and the terminal.

In one embodiment, the input matrix of the DFT transformation ( ) is a matrix generated by extracting the lth layer of each subband where CSI-RS was received from the SD compressed first compressed data. It may be in the form. can be expressed based on Equation 1.

[Equation 1]

In one embodiment, the first sub-transformation block 421 generates second compressed data by compressing the first compressed data in the frequency domain using a DFT function of a size corresponding to the number of subbands in which the CSI-RS is received. You can. A detailed description of this will be provided later in FIGS. 5 to 6B. The second sub-conversion block 422 may generate second compressed data by compressing the first compressed data in the frequency domain using a DFT function in which the CSI-RS is oversampled by the number of subbands in which the CSI-RS is received. . A detailed description of this will be provided later in FIGS. 7 to 8E. The third sub-transformation block 423 converts the first compressed data into the frequency domain using a partial DFT function of a type determined based on the number of subbands constituting the BWP and the number of subbands in which the CSI-RS is received. The second compressed data can be generated by compression. A detailed description of this will be provided later in FIGS. 9 to 10D. The fourth sub-conversion block 424 performs preprocessing on the subband in which CSI-RS is not received among the subbands constituting the BWP and compresses the preprocessed first compressed data in the frequency domain using the DFT function. Thus, second compressed data can be generated. A detailed description of this will be provided later in FIGS. 11 to 12g.

The FD basis selection block 426 may receive the second compressed data from the DFT conversion block 421 and select the dominant basis of the second compressed data as the FD basis. Here, the FD basis may mean the index of a column with a dominant value among the first compressed data re-expressed in DFT space. For example, the FD basis selection block 426 calculates the average value of the squares of the components for each column of the second compressed data on which FD compression was performed, sorts them according to size, and then selects a predetermined number of FD basis. You can select (e.g., select the order of the average squared value of each column's components in the order of the largest size) and output it.

NZC selection and quantization block 427 is the 'SD basis The absolute values of the components included in the second compressed data in the form of 'FD basis' can be calculated, sorted according to size, and then a predetermined number of NZCs can be selected (e.g., selection in order of the largest absolute value). The NZC selection and quantization block 427 may quantize the selected FD basis and NZC into a form that can be represented in the UCI bit sequence.

However, the UCI bit sequence generation block 430 may receive the quantized FD basis and NZC from the NZC selection and quantization block 427 and generate a UCI bit sequence for CSI reporting to the base station.

According to an embodiment of the present disclosure, when a CSI-RS is transmitted from a base station through some subbands in a BWP, frequency domain compression is efficiently performed to the extent that the channel information of the subband through which the CSI-RS is transmitted is not damaged, and the channel A wireless communication device that maximizes information compression performance can be provided.

A wireless communication device capable of preventing modification and contamination (or distortion) of CSI report content due to interference between channels can be provided through a compression process of channel information in the frequency domain according to the technical idea of the present disclosure.

Figure 5 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.

In detail, when CSI-RS is received in some subbands of the entire BWP in the baseband processor 110 of the wireless communication device 100 of FIG. 2, the baseband processor 110 (e.g., the first subband of FIG. 4) This is a diagram to explain the operation of performing CSI-RS dimension FD compression on channel characteristic information by the conversion block 422).

In this specification, the CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on .

Referring to FIG. 5, the operation of generating channel information by compressing channel characteristic information in the spatial domain and compressing the frequency domain may include steps S10, S20, S30, S40, S50, S60, and S70.

In step S10, the baseband processor 110 may receive a CSI-RS from the base station. For example, the base station transmits CSI-RS to the terminal using a predefined antenna port and wireless communication resources (e.g., time/frequency RE (resource element)).

In step S20, the baseband processor 110 may identify whether CSI-RS is received through some subbands of the BWP. Since CSI-RS can be freely allocated within the BWP by the base station, it can be transmitted not only on all subbands within the BWP, but also only on some subbands within the BWP. When CSI-RS is received only on some subbands within the BWP, 1) when CSI-RS is received only on some subbands within the BWP, and 2) the base station reports interest through CSI-reporting band information (e.g. bit sequence) This can include cases where a subband is specified and a CSI-report is requested only for that subband.

The baseband processor 110 may perform step S30 when the CSI-RS is received through some subbands of the BWP. If the CSI-RS is received through all subbands of the BWP, in step S40, the baseband processor 110 may generate channel information by estimating the channel based on the CSI-RS.

In step S30, the baseband processor 110 compresses the channel characteristic information of the subband in which the CSI-RS is received in the spatial domain (hereinafter referred to as SD compression) to generate first compressed data. You can. For example, the baseband processor 110 regenerates the spatial domain characteristics (e.g., values corresponding to antenna ports) of the subband in which the CSI-RS was received into an oversampled DFT (Discrete Fourier Transform) space. After expressing, select the dominant SD basis among the SD basis. The baseband processor 110 may generate first compressed data composed of selected SD basis instead of the basis that constitutes the existing BWP. That is, the first compressed data may be configured in the form of a matrix whose dimensions are reduced by the selected SD basis compared to before compression.

In step S50, the baseband processor 110 may generate second compressed data using a DFT function with a size corresponding to the number of subbands in which the CSI-RS is received. That is, the baseband processor 110 may generate second compressed data by compressing the first compressed data in the frequency domain (hereinafter referred to as FD compression) using the DFT function. For example, the baseband processor 110 may select an FD basis that represents the index of a column with a dominant value among the second compressed data obtained by re-expressing the first compressed data in the DFT space. Additionally, the baseband processor 110 may calculate the absolute values of the components included in the second compressed data (e.g., matrix data) in the DFT transformation space and select a predetermined number of NZCs according to the size of the absolute value. there is. The baseband processor 110 may quantize channel information including the selected FD basis and NZC to represent the channel information in a UCI bit sequence. A detailed description of this will be provided later in FIGS. 6A and 6B.

In step S60, the baseband processor 110 may generate channel information based on the second compressed data. For example, baseband processor 110 may generate a UCI bit sequence based on quantized channel information (e.g., information about the selected FD basis and NZC).

In step S70, the baseband processor 110 may report channel information to the base station. The base station can determine a precoder for downlink data transmission by receiving a spatial domain/frequency domain compressed channel information report from the wireless communication device. Additionally, in an embodiment according to the present disclosure, the base station may re-perform CSI-RS configuration and CSI configuration based on the channel information report of the wireless communication device. The base station can know the amount of information in the channel based on the spatial domain/frequency domain compressed channel information report of the wireless communication device. The amount of information in the channel can be determined based on the energy distribution of NZCs corresponding to the reported FD basis. For example, if the energy of NZCs is focused on some FD basis, the base station can control the wireless communication device to increase the compression rate of channel information to reduce the amount of overhead generated by CSI reporting as much as possible.

Therefore, the wireless communication system according to an embodiment of the present disclosure improves spectral efficiency by transmitting data only to specific wireless communication resources by adjusting the size of the CSI-RS allocation area according to the amount of channel information by the base station. There is an effect that can increase it. Additionally, a wireless communication device according to the technical idea of the present disclosure can prevent modification and distortion of CSI report content due to interference through a compression process in the frequency domain (FD).

6A and 6B are diagrams for explaining an FD compression operation by a first sub-transform block according to an exemplary embodiment of the present disclosure.

In detail, FIGS. 6A and 6B show diagrams for explaining the FD compression operation by the first sub-transformation block 422 of FIG. 4.

Figure 6a shows the first case in step S20 of Figure 5, where CSI-RS is received in some subbands in the BWP, and Figure 6b shows the second case, by the base station in step S20 of Figure 5. This shows a case where CSI-reporting band information (e.g. bit sequence) is requested only for the subband of interest.

In this specification, the CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on .

6A and 6B show a DFT function (e.g., CSI-RS dimension) set by the baseband processor 110 to correspond to the size of the DFT transform (e.g., K-point) to the number of subbands in which the CSI-RS was received. The second compressed data can be generated using the DFT function of .

Referring to FIG. 6A, in the first case, the BWP 610 for communication between the base station and the wireless communication device 100 is the first subband (620) including the subband 620 on which the CSI-RS was received. ) to nth subband ( ) includes.

In one embodiment, in the first case, the baseband processor 110 (e.g., the CSI compression circuit 116) provides a DFT function of a size corresponding to the number of subbands in which the CSI-RS is received ( ) (e.g., CSI-RS dimension DFT function) to compress the first compressed data in the frequency domain (hereinafter referred to as FD compression) to produce the second compressed data ( ) can be generated (at this time, FD compression can be performed for each layer on the first compressed data). For example, the second compressed data ( ) can be calculated based on Equation 2.

[Equation 2]

here, is the input matrix of the DFT transformation and is determined based on Equation 1 in FIG. 4, Is of size -means point DFT matrix, may mean the number of subbands in which CSI-RS was received.

Referring to Figure 6b, in the second case, the BWP 610 is the first subband (620) including the subband 620 on which the CSI-RS was received. ) to nth subband ( ) includes. For example, the base station displays a bit sequence (e.g., CSI-reporting band information) indicating the interest subband 651 as '1' (active) and the non-interest subband 652 as '0' (inactive). ) can be transmitted to the wireless communication device 100.

In the second case, if there is an uninteresting subband among the subbands on which the CSI-RS was received, the baseband processor 110 (e.g., the CSI compression circuit 116) sets the DFT size for FD compression to ' ' can be decided. That is, the baseband processor 110 also processes the second compressed data based on Equation 3 below: ) can be generated (at this time, FD compression can be performed for each layer on the first compressed data).

[Equation 3]

here, is the input matrix of the DFT transformation for the subbands of interest and is determined based on Equation 1 in FIG. 4, Is It may mean a DFT function (e.g., a DFT function in the CSI-RS dimension) set to a size corresponding to .

After FD compression, the baseband processor 110 calculates and sorts the norm of each column of the second compressed data to determine (or select) the index of the column with the dominant value as the FD basis. You can.

Figure 7 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.

In detail, when CSI-RS is received in some subbands of the entire BWP in the baseband processor 110 of the wireless communication device 100 of FIG. 2, the baseband processor 110 (e.g., the second subband of FIG. 4) This is a diagram to explain the operation of performing FD compression in the CSI-RS dimension (e.g., applying oversampled DFT) by performing FD compression in the CSI-RS dimension and then mapping it to FD compression in the BWP dimension.

Referring to FIG. 7, the operation of performing FD compression in the CSI-RS dimension and then mapping to the BWP dimension may include steps S51, S53, and S55. In this specification, the CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on .

In step S51, the baseband processor 110 determines the number of subbands on which the CSI-RS was received ( ) vs. BWP( It is possible to identify whether the ratio (Z) of the number of subbands constituting ) is an integer. Here Z is ' It can mean '. For example, if the number of subbands constituting the BWP is '6' and the number of subbands on which CSI-RS is received is '2', Z is an integer of '3'. For example, if the number of subbands constituting the BWP is '7' and the number of subbands on which CSI-RS is received is '2', Z is '3.5', which is not an integer.

In step S53, the baseband processor 110 may generate second compressed data in the CSI-RS dimension using an oversampled DFT function. The baseband processor 110 may generate an oversampled DFT function. The oversampling factor is 'Z( )'. For example, the baseband processor 110 applies at least one of a rotation index or a position indication matrix of the CSI-RS to an oversampled DFT function (e.g., a DFT function in the CSI-RS dimension). can be created. The baseband processor 110 may generate second compressed data by compressing the first compressed data in the frequency domain using an oversampled DFT function. A detailed description of this is described later in FIGS. 8A to 8E.

In step S55, the baseband processor 110 may generate channel information by mapping the second compressed data in the CSI-RS dimension to the BWP dimension.

After applying the oversampled DFT, the baseband processor 110 may select the FD basis and NZC based on the FD basis and NZC selection method described above in FIG. 4.

The baseband processor 110 may multiply the FD basis selected in the CSI-RS dimension by a ratio (Z) to map the FD basis selected in the CSI-RS dimension to the FD basis in the BWP dimension, or the baseband processor 110 ) can map the FD basis selected in the CSI-RS dimension to the FD basis in the BWP dimension by adding a rotation index to the value multiplied by the ratio (Z) to the FD basis selected in the CSI-RS dimension.

The baseband processor 110 may perform phase compensation on the NZC selected in the CSI-RS dimension according to a predetermined method in order to map the NZC selected in the CSI-RS dimension to the NZC in the BWP dimension. A detailed description of this is described later in FIGS. 8A to 8E.

In FIG. 7, the description is made on the assumption that CSI-RS level FD compression is performed based on the DFT function of FIG. 5, but the baseband processor 110 according to an embodiment of the present disclosure is not limited thereto and may perform various types of DFT. Using the function, you can perform FD compression at the CSI-RS level and map the result to the BWP level. In addition, the FD compression operation of FIG. 7 involves mapping channel characteristic information to high-dimensional (e.g., BWP dimension) FD compression after low-dimensional (e.g., CSI-RS dimension) FD compression in the wireless communication device 100. It can be applied as an independent embodiment.

The baseband processor 110 according to an embodiment of the present disclosure can replace BWP-level FD compression with CSI-RS-level FD compression, thereby reducing the amount of overhead generated in the FD compression process and reducing energy consumption. It has the effect of reducing. Additionally, a wireless communication device according to the technical idea of the present disclosure can prevent modification and distortion of CSI report content due to interference through a compression process of channel information in the frequency domain.

8A to 8E are diagrams for explaining an FD compression operation by a second sub-transform block according to an exemplary embodiment of the present disclosure.

In detail, FIGS. 8A to 8E illustrate the FD compression operation (e.g., mapping to FD compression in the BWP dimension after FD compression in the CSI-RS dimension) by the second sub-transformation block 423 of FIG. 4. A drawing is shown for.

The CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on . In addition, Z is the number of subbands on which CSI-RS was received ( ) compared to the number of subbands included in BWP ( ) can be expressed as an integer.

FIG. 8A shows a wireless communication environment 800 for performing FD compression (eg, FIGS. 8B to 8E) by the second sub-conversion block 423 of FIG. 4. For example, the wireless communication environment 800 may be configured when CSI-RS is received in some contiguous subbands of the BWP, or by the base station, only for some contiguous subbands in the BWP in the subband of interest (e.g., the channel in FIG. 8A This may include the case of receiving a channel information reporting band (CSI reporting band) set to a subband marked '1' in the bitmap of the information reporting band.

Referring to FIG. 8A, the wireless communication environment 800 of FIGS. 8B to 8E includes a BWP 810 for communication between a base station and the wireless communication device 100. subbands (e.g. the first subband ( ) to nth subband ( )), some subbands 820 on which CSI-RS are received are subbands (e.g., the subband where reception of CSI-RS begins ( ) to the subband where reception of CSI-RS ends ( )) can be assumed to be included. At this time, some subbands 820 where CSI-RS is received may be continuous subbands in the frequency domain.

Referring to FIGS. 8B and 8C, a first oversample DFT block 830 in the BWP dimension and a second oversample DFT transform block 840 in the CSI-RS dimension are shown.

In Figure 8b, the first DFT input matrix of the first oversample DFT block 830 ( )(831) is 'L x 'Indicates a matrix of size, and the first DFT input matrix ( ) The area (831) where the CSI-RS was received in (831) is 'L x 'It can be expressed as a matrix of sizes.

The first oversample DFT block 830 is a first DFT function ( ) can be used to perform BWP-level FD compression. Here, the first DFT function ( ) may mean a partial DFT function of the BWP dimension.

The first DFT function ( )silver ' x 'Can represent a matrix of size (e.g. partial DFT matrix). The first DFT function ( ), the area 832 corresponding to the subband on which the CSI-RS was received contains DFT columns that rotate according to a predetermined period (e.g., the first DFT column 832-1, the second DFT column 832 -2),...,The z DFT column (832-z)) may be included. At this time, the number of rotated DFT columns and the type of rotated DFT columns are the number of subbands on which CSI-RS was received ( ) compared to the number of subbands that make up the BWP ( ) can be determined based on the ratio (Z). After the first oversample DFT block 830, the FD basis and NZC can be selected according to the method described in FIG. 4.

In FIG. 8C, the second oversample DFT block 840 is a second oversample DFT function in the CSI-RS dimension ( ) can be used to perform BWP-level FD compression.

The second DFT input matrix of the second oversample DFT block 840 ( )(841) is ' x 'It can be expressed as a matrix of sizes. The second DFT function of the second oversample DFT block 840 ( ) (e.g., the first oversample DFT function (842-1) to the zth oversample DFT function (842-z)) is ' x 'It can represent a matrix of sizes. For example, each of the first oversample DFT function 842-1 to the zth oversample DFT function 842-z is ' x 'Can contain orthogonal matrices of size.

The second oversample DFT block 840 is based on Equation 4, the second DFT input matrix ( ) DFT transformation result for (841) ( ) can be calculated.

[Equation 4]

here, ' is a matrix indicating the rotation index for each oversampled DFT function. x 'It can be composed of a diagonal matrix of sizes. ' is a matrix indicating the start position of CSI-RS reception. x 'It can be composed of a diagonal matrix of sizes. for example, is a DFT function in the BWP dimension with Z x 'When it can be divided into orthogonal matrices of size, each orthogonal matrix is ' x 'Size of It can mean a rotation matrix to be expressed as .

The rotation index and FD basis selection block 843 may determine (or select) the rotation index and FD basis in the CSI-RS dimension after DFT transformation based on Equation 5.

[Equation 5]

The -point DFT mapping block 845 can map the rotation index and FD basis in the CSI-RS dimension to the BWP dimension based on Equation 6.

[Equation 6]

Here, Z is the number of subbands on which CSI-RS was received ( ) compared to the number of subbands that make up the BWP ( ) means the ratio of may mean a rotation index.

The NZC phase compensation block 847 can map the selected NZC in the CSI-RS dimension to the BWP dimension based on Equation 7.

[Equation 7]

Number of subbands in which CSI-RS was received ( ) compared to the number of subbands that make up the BWP ( If the ratio of ) is an integer, -The second compressed data output from the point DFT mapping block 845 is a bypass path 848 (e.g., the bypass path 848 is the number of subbands on which the CSI-RS was received ( ) vs. BWP( ) can be used when the ratio of the number of subbands constituting the subband is an integer), thereby skipping the phase compensation process and generating channel information.

When performing FD compression based on a DFT transform block (e.g., a second oversample DFT block 840) according to an embodiment of the present disclosure, a DFT transform block (e.g., a first oversample DFT block 830) according to a comparative example is used. ), by performing low-dimensional FD compression, the overhead occurring during the FD compression process can be significantly reduced, thereby maximizing the efficiency of FD compression.

Referring to FIG. 8D, an example of phase compensation according to the start position of the CSI-RS of the second oversample DFT transform block 840 of FIG. 8C is shown. In detail, for phase compensation according to the start position of CSI-RS Examples of application timing may include a first case 853 and a second case 854.

The third oversample DFT block 850 in the first case 853 is the third DFT function of the CSI-RS dimension ( ) can be used to perform BWP-level FD compression. Here, the third DFT function ( ) may mean an oversampled DFT function.

The third DFT input matrix of the third oversample DFT block 850 ( )(851) is 'L x 'It can be expressed as a matrix of sizes. The third DFT function of the third DFT transform block 850 ( ) (e.g. first oversample DFT function ( )(852-1) to zth oversample DFT function ( ))silver ' x 'It can represent a matrix of sizes. For example, the first oversample DFT function ( ) (852-1) to zth oversample DFT function ( ) (852-z) each is ' x 'Can contain orthogonal matrices of size.

The third oversample DFT block 850 is based on Equation 8, and the third DFT input matrix ( ) DFT transformation result for (851) ( ) can be calculated.

[Equation 8]

here, ' is a matrix indicating the rotation index for each oversampled DFT function. x 'It can be composed of a diagonal matrix of sizes.

After the third oversample DFT block 850, the rotation index and FD basis are selected according to the method described in the second oversample DFT block 840 of FIG. 8C, and the rotation index and FD basis in the CSI-RS dimension are selected. It can be mapped to the BWP dimension.

The NZC phase compensation block 855 indicates the start position of the received subband of CSI-RS. By applying , the phase required for mapping NZC in the CSI-RS dimension to the BWP dimension can be compensated.

The NZC selection and quantization block may select a dominant NZC among NZCs mapped to the BWP dimension based on the method described above in FIG. 4 and perform quantization for generating channel information (e.g., UCI bit sequence). That is, the first case 853 is By applying before NZC selection and quantization, the NZC can be selected based on the DFT results mapped to the BWP dimension.

The oversample DFT block 860 in the second case 854 is the same as the third oversample DFT block 850, and includes a rotation index and FD basis selection block, The -point DFT mapping block may also be the same as the first case 853.

However, the second case (854) is different from the first case (853), The application timing of can be applied after NZC selection and quantization. That is, the second case (854) is By applying after NZC selection and quantization, NZC can be selected based on the DFT results in the CSI-RS dimension and mapping to the BWP dimension can be performed.

The first case 853 and the second case 854 in FIG. 8D are Although the timing of application is different, the FD basis and NZC of the finally selected BWP dimension in each case may be the same.

Referring to Figure 8e, the number of subbands in which CSI-RS was received ( ) compared to the number of subbands that make up the BWP ( When the ratio (Z) of ) is not an integer, an example of FD compression through DFT that does not consider the effect of oversample is shown.

The fourth oversample DFT block 870 is a CSI-RS dimension DFT function ( ) can be used to perform BWP-level FD compression. Here, the DFT function ( ) may refer to a function that does not take into account the effects of oversampled DFTs or uses only some of the oversampled DFTs (e.g. is considered as 1).

The fourth DFT input matrix of the fourth oversample DFT block 870 ( )(871) is 'L x 'It can be expressed as a matrix of sizes.

The fourth oversample DFT block 870 is based on Equation 9, the fourth DFT input matrix ( ) DFT transformation result for (871) ( ) can be calculated.

[Equation 9]

here, ' is a matrix indicating the rotation index for each oversampled DFT function. x 'It can be composed of a diagonal matrix of sizes.

In one embodiment, the number of subbands on which CSI-RS was received ( ) compared to the number of subbands that make up the BWP ( If the ratio (Z) of ) is not an integer, the oversampled DFT effect is not considered, can be regarded as 1 (e.g., DFT function 872 in FIG. 8E). In this case, the FD basis in the CSI-RS dimension after DFT conversion is 'in Equation 5 of FIG. 8C described above. ' is determined (or selected) by removing (i.e., not selecting a rotation index), and the FD basis selected in the CSI-RS dimension can be mapped to the BWP dimension based on Equation 6 described above. Additionally, the phase compensation embodiment according to the start position of the CSI-RS of FIG. 8D is applicable to the embodiment of FIG. 8E.

Figure 9 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.

In detail, when CSI-RS is received in some subbands of the entire BWP in the baseband processor 110 of the wireless communication device 100 of FIG. 2, the baseband processor 110 (e.g., the third subband of FIG. 4) This is a diagram to explain the operation of performing BWP-level FD compression (e.g., applying partial DFT) by the transform block 424).

In this specification, the CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on .

Referring to FIG. 9, the operation of performing FD compression by applying partial DFT may include steps S210, S220, S230, S240, S250, S260, and S270. Here, steps S210 to S240 and steps S260 to S270 correspond to each of the steps S10, S20, S30, S40, S60, and S70 in FIG. 4, so the description is redundant. can be replaced with the explanation of FIG. 4.

In step S250, the baseband processor 110 may generate second compressed data using a partial DFT function.

For example, the baseband processor 110 may generate second compressed data by compressing SD-compressed first compressed data in the frequency domain (hereinafter referred to as FD compression) using a partial DFT function. there is. For example, the baseband processor 110 may select an FD basis that represents the index of a column with a dominant value among the second compressed data obtained by re-expressing the first compressed data in the partial DFT space. Additionally, the baseband processor 110 may calculate the absolute values of the components included in the second compressed data (e.g., matrix data) in the DFT transformation space and select a predetermined number of NZCs according to the size of the absolute value. there is. The baseband processor 110 may quantize channel information including the selected FD basis and NZC to represent the channel information in a UCI bit sequence. A detailed description of this will be provided later in FIGS. 10A and 10D.

The wireless communication system according to an embodiment of the present disclosure performs FD compression through partial DFT according to the amount of channel information by the base station to adjust the size of the CSI-RS allocation area, thereby transmitting data only to specific wireless communication resources, thereby saving resources. It has the effect of improving efficiency. Additionally, a wireless communication device according to the technical idea of the present disclosure can prevent modification and distortion of CSI report content due to interference through a compression process in the frequency domain (FD).

10A to 10D are diagrams for explaining an FD compression operation by a third sub-transform block according to an exemplary embodiment of the present disclosure.

In detail, FIGS. 10A and 10D show diagrams for explaining the FD compression operation by the third sub-conversion block 424 of the baseband processor 110 of FIG. 4.

FIG. 10A shows a diagram for explaining the partial DFT function and the resulting DFT transformation result of step S250 of FIG. 9.

Referring to Figure 10a, the base station is connected to BWP (1001). subbands are allocated, and in the area where CSI-RS is transmitted (e.g., some subband areas of BWP (1001)) (1002) It is assumed that subbands (or frequency resources) are allocated.

The baseband processor 110 is -Partial DFT function for FD compression based on the DFT basis of the position of the subband corresponding to the area where the CSI-RS is received from the point DFT matrix (or DFT function) ( ) can be created. For example, the partial DFT function ( )Is It may refer to a partial DFT matrix of size.

The baseband processor 110 generates a DFT input matrix ( ) Partial DFT transformation results for ( ) can be calculated.

[Equation 10]

The baseband processor 110 produces partial DFT transformation results ( ) Optimized partial DFT transformation results based on Equation 11 according to the sparsity characteristics of ( ) can be calculated.

[Equation 11]

here, may refer to a set of position indices of non-zero or significant coefficients of vector a. M may refer to a parameter required for selecting the FD basis. For example, the baseband processor 110 produces a partial DFT transformation result ( ) can be derived. Examples of related algorithms that can be used may include a basis pursuit (BP) algorithm related to convex relaxation, a basis pursuit with inequality constraints (BPIC) algorithm, and a basis pursuit denoising (BPDN) algorithm. In addition, greedy pursuit-related OMP (orthogonal matching pursuit) algorithm, StOMP (stagewise orthogonal matching pursuit) algorithm, R-OMP (regularized orthogonal matching pursuit) algorithm, CoSaMP (Compressive sampling matching pursuit) algorithm, IHT (iterative hard thresholding (TST) algorithm, two-stage thresholding (TST) algorithm, subspace pursuit (SP) algorithm, etc. can be used. Alternatively, a method of finding an optimized DFT result by substituting possible candidates from a brute force perspective can be used.

Figure 10b shows the partial DFT transformation result derived from Equation 11 of Figure 10a ( ) is shown.

Referring to FIG. 10B, the baseband processor 110 generates a DFT input matrix ( )(1021) with the partial DFT function ( )(1022) based on FD compression to obtain partial DFT transform results ( )(1023) can be derived. For example, the DFT input matrix ( )(1021), when re-expressed in a partial DFT space, can appear as a column vector (or column index) 1024 with a dominant value. The baseband processor 110 may determine (or select) the column vector (or column index) 1024 as the FD basis.

Figure 10c shows a partial DFT function according to one embodiment when there is an 'inactive' subband in the CSI-RS reporting band received from the base station.

Referring to Figure 10c, the DFT input matrix ( )(1031) is 'L x 'It consists of a matrix of size, and the partial DFT function ( )(1032) is ' x 'It can be composed of a DFT matrix of size.

The baseband processor 110 produces a partial DFT transformation result based on Equation 12 ( ) can be calculated.

[Equation 12]

The baseband processor 110 produces the optimized partial DFT transformation result ( ) can be calculated.

Figure 10d shows a partial DFT function according to another embodiment when there is an 'inactive' subband in the CSI-RS reporting band received from the base station.

If there is an 'inactive' subband in the CSI-RS reporting band received from the base station, the baseband processor 110 uses the DFT input matrix ( ) (1041) is optimized by padding the 'inactive' subband 1043 with a specific value (e.g. '0') and re-expressing it in DFT space in a manner similar to FIG. 10b (e.g. Equation 11) DFT transformation results can be derived.

Figure 11 is a flowchart showing a method of operating a wireless communication device according to an exemplary embodiment of the present disclosure.

In detail, when CSI-RS is received in some subbands of the entire BWP in the baseband processor 110 of the wireless communication device 100 of FIG. 2, the baseband processor 110 (e.g., the fourth subband of FIG. 4) This is a diagram to explain the operation of performing BWP-level FD compression (e.g., applying DFT after performing preprocessing) by the transform block 425).

In this specification, the CSI-RS dimension is the number of some subbands in the BWP where CSI-RS was received ( ), and the BWP dimension is the number of subbands included in the BWP ( ) may refer to a DFT space converted based on .

Referring to FIG. 11, the operation of performing FD compression by applying DFT after performing preprocessing may include steps S310, S320, S330, S340, S351, S352, S360, and S370. Here, steps S310 to S340 and steps S360 to S370 correspond to each of the steps S10, S20, S30, S40, S60, and S70 in FIG. 4, so the description is redundant. can be replaced with the explanation of FIG. 4.

In step S351, the baseband processor 110 may perform preprocessing on the first compressed data according to a predetermined method. Here, the first compressed data is the DFT input matrix (SD compressed result) ) may include.

If CSI-RS is received in some subbands of the entire BWP, the baseband processor 110 performs preprocessing on the subbands for which CSI-RS is not received, and performs a BWP-dimensional DFT input matrix ( ) can be configured. For example, preprocessing methods may include a zero padding method, a zero interpolation method, a phase difference rotation method, a mirror copy method, a repeating method, etc. A detailed description of this will be provided later with reference to FIGS. 12A to 12G.

For example, the baseband processor 110 may generate first compressed data (e.g., a DFT input matrix in the BWP dimension ( )) can be selected, which represents the index of the column with the dominant value among the second compressed data re-expressed in the DFT space. Additionally, the baseband processor 110 may calculate the absolute values of the components included in the second compressed data (e.g., matrix data) in the DFT transformation space and select a predetermined number of NZCs according to the size of the absolute value. there is. The baseband processor 110 may quantize channel information including the selected FD basis and NZC to represent the channel information in a UCI bit sequence.

In step S352, the baseband processor 110 may generate second compressed data using a DFT function with a size corresponding to the number of subbands constituting the BWP. For example, the baseband processor 110 configures the BWP-dimensional DFT input matrix ( ), you can perform BWP-level FD compression by performing DFT transformation.

A wireless communication device according to an embodiment of the present disclosure performs preprocessing on a subband in which CSI-RS is not transmitted, and a BWP-dimensional DFT input matrix ( ), thereby complying with the FD compression-related standards of communication standards (e.g., 3GPP Rel. 16 to 17) (e.g., performing FD compression through DFT transformation at the BWP level), while reducing the overhead arising from FD compression through the preprocessing process. It has a reducing effect. Additionally, a wireless communication device according to the technical idea of the present disclosure can prevent modification and distortion of CSI report content due to interference through a compression process in the frequency domain (FD).

12A to 12G are diagrams for explaining an FD compression operation by a fourth sub-transform block according to an exemplary embodiment of the present disclosure.

In detail, FIGS. 12A and 12G show diagrams for explaining the FD compression operation by the fourth sub-conversion block 425 of the baseband processor 110 of FIG. 4. The horizontal axis of FIGS. 12A and 12G may represent the subband area of the frequency domain, and the vertical axis may represent the precoding vector of the subband. For convenience of explanation, FIGS. 12A and 12G assume that CSI-RS is not allocated to a subband in the low-frequency band, and in the embodiments of FIGS. 12A and 12G, the location of the subband to which CSI-RS is not allocated is changed. It is still applicable.

FIG. 12A shows a diagram for explaining the first preprocessing method and the second preprocessing method in step S531 of FIG. 11. In FIG. 12A, it is assumed that the first area 1201 is a subband area to which CSI-RS is not allocated, and the second area 1202 is a subband area to which CSI-RS is allocated.

The first preprocessing method may include a linear interpolation method (eg, zero interpolation method).

For example, the baseband processor 110 sets the precoding vector 1203 of the first subband of the first area 1201 to the zero vector, and sets the CSI of the second area 1202 to the zero vector. -Perform linear interpolation with the precoding vector (1204) of the first subband to which RS is assigned to the DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 13.

[Equation 13]

here, ego, means the number of precoding vectors of subbands for which CSI-RS is not allocated, silver CSI-RS may mean the index of a subband to which no CSI-RS has been allocated.

Although not shown in FIG. 12A, the second preprocessing method may include a zero padding method.

The baseband processor 110 pads the first region 1201 with a specific value (e.g., '0') to determine the DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 14.

[Equation 14]

FIG. 12B shows a diagram for explaining the third preprocessing method in step S531 of FIG. 11. In FIG. 12b, it is assumed that the first area 1211 is a subband area to which CSI-RS is not allocated, and the second area 1212 is a subband area to which CSI-RS is allocated.

The third preprocessing method may include a linear interpolation method applying phase difference rotation (e.g., a zero interpolation method based on phase difference rotation).

For example, the baseband processor 110 sets the precoding vector 1213 of the first subband of the first area 1211 to a zero vector, and sets the precoding vector 1213 of the first subband of the first area 1211 to the After performing linear interpolation with the band's precoding vector (1214), phase rotation is applied to the DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 15.

[Equation 15]

here, ego, means the number of precoding vectors of subbands for which CSI-RS is not allocated, silver CSI-RS may mean the index of a subband to which no CSI-RS has been allocated. is a phase difference rotation matrix and can be defined based on Equation 16, Is The phase difference between the components of vector 1214 is A vector that increases by can be defined based on Equation 17.

[Equation 16]

[Equation 17]

Additionally, in Equation 15 The value is determined differently depending on the phase difference rotation method, which includes 1) random phase difference rotation method (e.g. 2) a random selection of values), and 2) a phase-difference cyclic shift method (e.g. method of applying) may be included. The baseband processor 110 according to an embodiment of the present disclosure is not limited to this and can apply various phase difference rotation methods.

FIG. 12C shows a diagram for explaining the fourth preprocessing method of step S531 of FIG. 11. In FIG. 12C, it is assumed that the first area 1221 is a subband area to which CSI-RS is not allocated, and the second area 1222 is a subband area to which CSI-RS is allocated.

The fourth preprocessing method may include a linear interpolation method using an average.

For example, the baseband processor 110 is the average vector of the precoding vector of the subband of the first area 1221 ( ) is calculated to calculate the precoding vector of the first subband (1223) to which CSI-RS is not assigned. is set, and linear interpolation is performed with the precoding vector of the first subband 1224 to which the CSI-RS of the second area 1222 is allocated, and the DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 18, and although not shown, phase difference rotation can also be applied.

[Equation 18]

here, ego, means the number of precoding vectors of subbands for which CSI-RS is not allocated, silver CSI-RS may mean the index of a subband to which no CSI-RS has been allocated. average vector ( ) can be calculated based on Equation 19.

[Equation 19]

FIG. 12D shows a diagram for explaining the fifth preprocessing method in step S531 of FIG. 11. In FIG. 12D, it is assumed that the first area 1231 is a subband area to which CSI-RS is not allocated, and the second area 1232 is a subband area to which CSI-RS is allocated.

The fifth preprocessing method may include a mirror copy method.

For example, the baseband processor 110 mirror-copies the precoding vector of the second area 1232 to the first area 1231 based on the first subband 1234 of the second area 1232 and inputs the DFT. procession( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 20.

[Equation 20]

here, ego, means the number of precoding vectors of subbands to which CSI-RS is not allocated, and n and m are CSI-RS may mean the index of a subband to which no CSI-RS has been allocated.

FIG. 12E shows a diagram for explaining the sixth preprocessing method of step S531 of FIG. 11. In FIG. 12e, it is assumed that the first area 1241 is a subband area to which CSI-RS is not allocated, and the second area 1242 is a subband area to which CSI-RS is allocated.

The sixth preprocessing method may include a repetition method.

For example, the baseband processor 110 repeatedly applies the precoding vector of the second area 1232 to the first area 1231 to provide a DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 21.

[Equation 21]

here, ego, means the number of precoding vectors of subbands for which CSI-RS is not allocated, and n is It can be defined as:

FIG. 12f shows a diagram for explaining the seventh preprocessing method in step S531 of FIG. 11. In FIG. 12F, it is assumed that the first area 1251 is a subband area to which CSI-RS is not allocated, and the second area 1252 is a subband area to which CSI-RS is allocated.

The seventh preprocessing method may include a repetition method applying zero padding.

For example, the baseband processor 110 repeatedly applies the precoding vector of the second area 1252 to the first area 1251 and applies a specific value to the remaining subband area 1253 of the first area 1251. (e.g. '0') to pad the DFT input matrix ( ) can be configured. At this time, the DFT input matrix ( ) can be expressed by Equation 22.

[Equation 22]

here, ego, means the number of precoding vectors of subbands for which CSI-RS is not allocated, and n is It can be defined as:

FIG. 12g shows a diagram for explaining the eighth preprocessing method of step S531 of FIG. 11. In FIG. 12g, it is assumed that the first area 1261 is a subband area to which CSI-RS is not allocated, and the second area 1262 is a subband area to which CSI-RS is allocated.

The eighth preprocessing method may include a wide band (WB) precoding method.

The baseband processor 110 is a matrix corresponding to the channel characteristic information of the nth subband after SD compression ( ) to the wide band matrix ( ) can be replaced. For example, the DFT block 1260 of the baseband processor 110 is the matrix of the lth layer of the CSI-RS area ( ) in the frequency domain, if the number of FD basis is identified as insufficient to effectively represent the frequency domain characteristics of the corresponding matrix (e.g. change in frequency aspect, etc.), the matrix of the lth layer of the CSI-RS area ( ), the matrix of the lth layer from a wide band perspective (rather than compressing and transmitting) ) can be quantized and transmitted to the base station. here, may include all CSI-RS channel information matrices in which the subband bitmap is 'active', or a matrix after the precoding of the base station determined by the terminal undergoes SD compression.

For example, the DFT block 1260 of the baseband processor 110 determines (or selects) a representative channel among subbands to which CSI-RS is allocated, and sets the channel value of the representative channel to all subbands of the entire BWP. After copying to the channel value, FD compression can be performed on the subbands of the entire BWP.

Figure 13 is a block diagram showing an electronic device according to an exemplary embodiment of the present disclosure.

The wireless communication device 1300 of FIG. 13 may correspond to the wireless communication device 100 of FIG. 1 .

Referring to FIG. 13, the electronic device may include a memory 1310, a processor unit 1320, an input/output control unit 1340, a display unit 1350, an input device 1360, and a communication processing unit 1390. there is. Here, there may be a plurality of memories 1310. A look at each component is as follows.

The memory 1310 may include a program storage unit 1311 that stores a program for controlling the operation of the electronic device and a data storage unit 1312 that stores data generated during program execution. The data storage unit 1312 may store data necessary for the operation of the application program 1313 and the CSI compression setting program 1314. The program storage unit 1311 may include an application program 1313 and a CSI compression setting program 1314. Here, the program included in the program storage unit 1311 may be expressed as an instruction set as a set of instructions.

The application program 1313 includes an application program that operates on the electronic device. That is, the application program 1313 may include instructions for an application driven by the processor 1322. According to exemplary embodiments of the present disclosure, when CSI-RS is allocated to only some subbands in the entire BWP, the CSI compression setting program 1314 performs a DFT function (e.g., : Frequency domain compression can be performed using a CSI-RS-level DFT function, partial DFT function, oversampled DFT function, etc.). .22

The peripheral device interface 1323 can control the connection between the input/output peripheral devices of the base station, the processor 1322, and the memory interface 1321. The processor 1322 controls the base station to provide the corresponding service using at least one software program. At this time, the processor 1322 may execute at least one program stored in the memory 1310 and provide a service corresponding to the program.

The input/output control unit 1340 may provide an interface between an input/output device such as the display unit 1350 and the input device 1360 and the peripheral device interface 1323. The display unit 1350 displays status information, input text, moving picture, and still picture. For example, the display unit 1350 may display application program information driven by the processor 1322.

The input device 1360 may provide input data generated by selecting an electronic device to the processor unit 1320 through the input/output control unit 1340. At this time, the input device 1360 may include a keypad including at least one hardware button and a touchpad that senses touch information. For example, the input device 1360 may provide touch information such as touch, touch movement, and touch release detected through the touch pad to the processor 1322 through the input/output control unit 1340. The electronic device may include a communication processing unit 1390 that performs communication functions for voice communication and data communication. The communication processing unit 1390 may include a plurality of antenna modules 1392 to support communication in the millimeter wave band according to example embodiments of the present disclosure.

Claims (20)

In a method of operating a wireless communication device,
Receiving a channel state information reference signal (CSI-RS) from a base station;
generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; and
Comprising reporting the channel information to the base station,
The steps for generating the channel information are:
Compressing channel characteristic information of the subband on which the CSI-RS was received in the spatial domain to generate first compressed data;
Using a first discrete Fourier transform (DFT) function of a size corresponding to the number of subbands on which the CSI-RS was received among the bandwidth parts (BWP) for communication with the base station, the first compressed data Compressing in the frequency domain to generate second compressed data; and
A method comprising generating the channel information based on the second compressed data.
In claim 1,
The step of generating the second compressed data is,
When receiving bitmap information indicating a subband of interest of the base station from the base station, the first compressed data is compressed to the frequency using a second DFT function of a size corresponding to the number of subbands of interest. The method further comprising generating the second compressed data by compressing it in a domain.
In claim 1,
When the ratio of the number of subbands on which the CSI-RS is received to the number of subbands constituting the BWP is an integer, the step of generating the second compressed data includes,
Generating an oversampled DFT function by applying at least one of a rotation index or a position indication matrix of the CSI-RS to the first DFT function; and
The method further comprising generating the second compressed data by compressing the first compressed data in the frequency domain using the oversampled DFT function.
In claim 3,
The number of rotation indices is,
A method characterized in that it is determined based on the ratio of the number of subbands on which the CSI-RS is received compared to the number of subbands constituting the BWP.
In claim 3,
If the ratio of the number of subbands constituting the BWP to the number of subbands on which the CSI-RS was received is an integer, the step of generating the channel information includes:
Based on the second compressed data, selecting an FD (frequency domain) column index corresponding to the reception area of the CSI-RS, and
The method further comprising mapping the FD column index to correspond to the BWP area.
In claim 5,
The step of mapping the FD column index is,
The rotation index is added to the FD column index multiplied by the ratio of the number of subbands constituting the BWP to the number of subbands on which the CSI-RS was received, and mapped to the FD column index corresponding to the BWP area. A method comprising the steps:
In claim 5,
If the ratio of the number of subbands constituting the BWP to the number of subbands on which the CSI-RS was received is an integer, the step of generating the channel information includes:
Selecting non-zero coefficients (NZC) based on a matrix composed of the first compressed data and a column vector corresponding to the FD column index, and
The method further comprising mapping the NZC to correspond to the BWP area.
In claim 5,
The step of selecting the NZC is,
A method comprising selecting the NZC based on absolute values of elements included in a matrix composed of the first compressed data and a column vector corresponding to the FD column index.
In claim 1,
If the ratio of the number of subbands on which the CSI-RS is received to the number of subbands constituting the BWP is not an integer, the step of generating the second compressed data includes,
Generating a fourth DFT function by applying the position indication matrix of the CSI-RS to the first DFT function; and
The method further comprising generating the second compressed data by compressing the first compressed data in the frequency domain using the fourth DFT function.
In a method of operating a wireless communication device,
Receiving a channel state information reference signal (CSI-RS) from a base station;
generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; and
Comprising reporting the channel information to the base station,
The steps for generating the channel information are:
Compressing channel characteristic information of the subband on which the CSI-RS was received in the spatial domain to generate first compressed data;
A first part DFT (partial discrete fourier) consisting of a column domain corresponding to a subband constituting a bandwidth part (BWP) for communication with the base station and a row domain corresponding to the subband on which the CSI-RS was received. generating second compressed data by compressing the first compressed data in the frequency domain using a transform) function; and
A method comprising generating the channel information based on the second compressed data.
In claim 10,
The step of generating the second compressed data is,
When receiving bitmap information indicating a subband of interest of the base station from the base station, a second device consisting of a column domain corresponding to a subband area constituting the BWP and a low domain corresponding to the subband of interest The method further comprising generating the second compressed data by compressing the first compressed data in the frequency domain using a partial DFT function.
In a method of operating a wireless communication device,
Receiving a channel state information reference signal (CSI-RS) from a base station;
generating channel information by estimating a channel between the wireless communication device and the base station based on the CSI-RS; and
Comprising reporting the channel information to the base station,
The steps for generating the channel information are:
Compressing channel characteristic information of the subband on which the CSI-RS was received in the spatial domain to generate first compressed data;
Performing preprocessing according to a predetermined method on a subband in which the CSI-RS is not received among the bandwidth part (BWP) for communication with the base station in the first compressed data;
Compressing the preprocessed first compressed data in the frequency domain using a discrete Fourier transform (DFT) function of a size corresponding to the number of subbands constituting the BWP to generate second compressed data; and
A method comprising generating the channel information based on the second compressed data.
In claim 12,
The step of performing the preprocessing is,
A method comprising the step of performing the preprocessing using a first preprocessing method of padding a subband in which the CSI-RS is not received among the BWPs with a specific predetermined value.
In claim 12,
The step of performing the preprocessing is,
A method comprising the step of performing the preprocessing using a second preprocessing method that performs linear interpolation on a subband in which the CSI-RS is not received among the BWP.
In claim 12,
The step of performing the preprocessing is,
A method comprising the step of performing the preprocessing using a third preprocessing method that performs linear interpolation and phase difference rotation on a subband in which the CSI-RS is not received among the BWP.
In claim 12,
The step of performing the preprocessing is,
Calculate the average value of the precoding vector of the subband in which the CSI-RS is received,
A method comprising the step of performing the preprocessing on a subband in which the CSI-RS is not received among the BWP using a fourth preprocessing method that performs linear interpolation based on the average value of the precoding vector. .
In claim 12,
The step of performing the preprocessing is,
Performing the preprocessing using a fifth preprocessing method of mirroring a subband in which the CSI-RS is not received among the BWPs with a precoding vector of the subband on which the CSI-RS is received. A method comprising:
In claim 12,
The step of performing the preprocessing is,
Comprising the step of performing the pre-processing on the subband in which the CSI-RS is not received among the BWP using a sixth pre-processing method of copying the precoding vector of the subband on which the CSI-RS was received. A method characterized by:
In claim 12,
The step of performing the preprocessing is,
A seventh preprocessing method that copies the precoding vector of the subband on which the CSI-RS was received to a subband in which the CSI-RS is not received among the BWP, and pads the remaining subbands after the copy with a specific predetermined value. A method comprising the step of performing the preprocessing using .
In claim 12,
The step of performing the preprocessing is,
Comprising the step of performing the preprocessing using an eighth preprocessing method of copying the average value of the precoding vector of the subband in which the CSI-RS was received to a subband in which the CSI-RS was not received among the BWP. A method characterized by:

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