KR20100034505A - Channel information feedback apparatus for generating multiple antenna beam in orthogonal frequency division multiplexing systems and method thereof - Google Patents

Abstract

PURPOSE: In the OFDM(Orthogonal Frequency Division Multiplexing) system, by using the space correlation information between the frequency correlation information between subcarrier and the multiple antenna the channel information feed backing apparatus and the method thereof for being created the multiple antenna beam are created the feedback information. CONSTITUTION: A transmitter(100) comprises the beam weighted value application part(102), the IDFT(Inverse Discrete Fourier Transform) part(104), the guard interval inserter(106), a plurality of transmission antennae and beam weighted value generator. A receiver comprises a plurality of RX-antennas, the guard interval canceller, the DFT part, the received signal processor and feedback information generator(120). The feedback information generator is created the feedback information for the beam forming of the transmission signal. The feedback information generator transmits the feedback information which becomes as described above with above beam weighted value generator of transmitter.

Description

Channel information feedback apparatus for generating multiple antenna beams in an OFM system and its method

The present invention relates to a channel information feedback apparatus and method for generating a multi-antenna beam in an OFDM system.

In a system using multiple transmit / receive antennas, if the transmitter knows channel information, the system capacity can be greatly increased through a transmission beamforming technique. In order to use this, feedback of channel information from the receiver to the transmitter is required. However, the amount of feedback information is greatly increased as the number of effective subcarriers increases in an Orthogonal Frequency Division Multiplexing (OFDM) system, which is a burden on the system.

Accordingly, many studies have been made to reduce the feedback information burden in an OFDM system using a plurality of transmit and receive antennas. The clustering technique of grouping several adjacent subcarriers into one cluster and returning beam weight information corresponding to the representative subcarriers of the cluster has an advantage of reducing the feedback amount in proportion to the cluster size. However, as the cluster size increases, system performance decreases, which can be overcome by interpolation techniques. That is, performance can be improved by interpolating channel information of a representative subcarrier of a cluster to obtain channel information of the remaining subcarriers. However, this technique has a disadvantage of additional feedback of phase information for interpolation.

Therefore, a technique for generating beam weight information of the current subcarrier using the beam weight information of the previous subcarrier has been proposed. This technique has an advantage of effectively reducing the amount of feedback information without additional phase information. Recently, a technique for generating beam weight information by generating feedback information in a time domain through an orthogonal transform based on a Discrete Fourier Transform (DFT) and performing inverse transformation on the transmitter has been proposed. This technique takes advantage of the fact that the gain of the channel is concentrated in a few multipaths in a high frequency correlation environment, which is advantageous in a small number of multipaths.

However, although these techniques all have in common that they use only correlation information in the frequency domain, they do not use correlation information between transmit and receive antennas that may exist in an actual channel, and thus, there is a problem in that feedback of channel information is large.

The present invention is to solve the problems of the prior art as described above, by generating feedback information using the frequency correlation information between subcarriers and the spatial correlation information between multiple antennas, multiple in an OFDM system to reduce the amount of feedback information A channel information feedback apparatus and method for generating an antenna beam are provided.

In addition, the present invention can reduce the amount of feedback information by using the frequency correlation information between the subcarriers and the spatial correlation information between the multiple antennas, so that the channel for generating a multi-antenna beam in an OFDM system to improve the performance of the system. An information feedback apparatus and method are provided.

To this end, a channel information feedback apparatus for generating a multi-antenna beam in an OFDM system according to an aspect of the present invention includes a transformer for converting the estimated channel information using a Discrete Fourier Transform (DFT) matrix and a transmission antenna correlation matrix; A quantizer for generating a vector including a predetermined number of main elements of the converted channel information and quantizing the generated vector based on a quantization codebook to generate feedback information for transmission beamforming; And it may include a feedback unit for feedback the generated feedback information to the transmitter.

Preferably, the converter converts the estimated channel information into the channel information of the time domain in the frequency domain using the DFT matrix, and performs spatial orthogonal transformation of the channel information converted into the time domain using the transmission antenna correlation matrix. can do.

에 의해 구해지고, 여기서, 상기 M은 송신안테나의 개수, 상기 K는 부반송파의 개수, 상기 q는 다중경로의 개수, 상기

은 채널의 i번째 다중경로의 이득, 상기

는 송신안테나 상관 행렬의 j번째 고유값, 상기 π_s(l) 및 π_f(l)는 주요 채널요소의 l번째 인덱스 번호, 그리고 상기

는 양자화 코드북의 특징에 따른 상수 값을 의미할 수 있다.Preferably, the quantizer generates a vector including a predetermined number of main channel elements of the transformed channel information, wherein the predetermined number L is expressed by an equation

Where M is the number of transmit antennas, K is the number of subcarriers, q is the number of multipaths, and

Is the gain of the i-th multipath of the channel,

Is the j th eigenvalue of the transmit antenna correlation matrix, π _s (l) and π _f (l) are the l th index number of the primary channel element, and

May mean a constant value according to the feature of the quantization codebook.

에 의해 구해질 수 있다. 또한, 상기

는 수학식

에 의해 계산된 양자화 코드북의 특징에 따른 상수 값을 의미하고, 여기서, 상기

을 의미하며, 상기 e는 평균이 0인 i.i.d. 가우 시안 랜덤 변수를 원소로 하는 크기가 L인 벡터를 의미할 수 있다.In this case, π _s (l) and π _f (l) is the equation

Can be obtained by In addition,

Is an equation

Means a constant value according to the characteristics of the quantization codebook calculated by

E may mean a vector having a size of L having an iid Gaussian random variable having an average of 0 as an element.

Preferably, if the estimated channel information is MIMO channel information, the converter converts the MIMO channel information into MISO channel information using a first column vector of a received antenna correlation matrix. The converted MISO channel information may be transformed using a Discrete Fourier Transform (DFT) matrix and a transmission antenna correlation matrix.

Preferably, the present invention provides an antenna correlation matrix estimator for estimating a transmission antenna correlation command and a reception antenna correlation matrix based on the estimated channel information; A multipath gain estimator for estimating a multipath gain based on the estimated channel information; And a main channel element determiner for determining the number and position information of the main channel elements based on the estimated multipath gain, wherein the feedback unit includes the transmission antenna correlation matrix and the main channel when channel characteristics change. The number of elements and their location information can be fed back to the transmitter.

In addition, the transmitter rearranges the elements of the channel information based on the feedback information, and inversely transforms the rearranged channel information using a transmission antenna correlation matrix and a DFT matrix, and uses the inverse transformed channel information to beam-weight the values. The transmission signal may be beamformed based on the beamweighting information generated by generating information.

According to another aspect of the present invention, a channel information feedback method for generating a multi-antenna beam includes converting estimated channel information by using a Discrete Fourier Transform (DFT) matrix and a transmission antenna correlation matrix; Determining a vector including a predetermined number of elements of the converted channel information and quantizing the determined vector based on a quantization codebook to generate feedback information for transmission beamforming; And feedbacking the generated feedback information to a transmitter.

Preferably, in the converting, the estimated channel information is converted into channel information of a time domain in a frequency domain using the DFT matrix, and the channel information converted into the time domain is spatial using a transmission antenna correlation matrix. Can be orthogonal.

에 의해 구해지고, 여기서, 상기 M은 송신안테나의 개수, 상기 K는 부반송파의 개수, 상기 q는 다중경로의 개수, 상기

은 채널의 i번째 다중경로의 이득, 상기

는 송신안테나 상관 행렬의 j번째 고유값, 상기 π_s(l) 및 π_f(l)는 주요 채널요소의 l번째 인덱스 번호, 그리고 상기

는 양자화 코드북의 특징에 따른 상수 값을 의미할 수 있다.The generating may generate a vector including a predetermined number of main channel elements of the converted channel information, wherein the predetermined number L is expressed by an equation

Where M is the number of transmit antennas, K is the number of subcarriers, q is the number of multipaths, and

Is the gain of the i-th multipath of the channel,

Is the j th eigenvalue of the transmit antenna correlation matrix, π _s (l) and π _f (l) are the l th index number of the primary channel element, and

May mean a constant value according to the feature of the quantization codebook.

에 의해 구해질 수 있다. 또한, 상기

는 수학식

에 의해 계산된 양자화 코드북의 특징에 따른 상수 값을 의미하고, 여기서, 상기

을 의미하며, 상기 e는 평균이 0인 i.i.d. 가우시안 랜덤 변수를 원소로 하는 크기가 L인 벡터를 의미할 수 있다.In this case, π _s (l) and π _f (l) is the equation

Can be obtained by In addition,

Is an equation

Means a constant value according to the characteristics of the quantization codebook calculated by

The e may mean a vector having a size of L having an iid Gaussian random variable having an average of 0 as an element.

Preferably, in the converting, if the estimated channel information is multi-input multi-output (MIMO) channel information, multi-input single output (MISO) channel information is obtained using the first column vector of a received antenna correlation matrix. The converted MISO channel information may be converted using a Discrete Fourier Transform (DFT) matrix and a transmission antenna correlation matrix.

Preferably, the present invention provides an antenna correlation matrix estimator for estimating a transmission antenna correlation command and a reception antenna correlation matrix based on the estimated channel information; A multipath gain estimator for estimating a multipath gain based on the estimated channel information; And a main channel element determiner for determining the number and position information of the main channel elements based on the estimated multipath gain, wherein the feedbacking step includes the transmission antenna correlation matrix when the channel characteristics change. The number of main channel elements and their position information can be fed back to the transmitter.

In addition, the transmitter rearranges the elements of the channel information based on the feedback information, inversely converts the rearranged channel information using a transmission antenna correlation matrix and a DFT matrix, and uses the inverse transformed channel information. The transmission signal may be beamformed based on the beamweighting information generated by generating weight information.

Hereinafter, a channel information feedback apparatus and method for generating a multi-antenna beam in an OFDM system according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be made based on the contents throughout the specification.

According to the present invention, channel information necessary for beamforming transmission in an orthogonal frequency division multiplexing (OFDM) wireless communication system using a plurality of transmit / receive antennas, in particular, frequency correlation between OFDM subcarriers and spatial correlation between transmit / receive antennas The present invention relates to a method for feeding back implied channel information.

1 is an exemplary view showing the configuration of a transceiver of an OFDM system according to an embodiment of the present invention.

As shown in FIG. 1, the transmitter 100 according to the present invention includes a beam weighting unit 102, an IDFT (Inverse DFT) unit 104, a guard interval inserter 106, and a plurality of transmit antennas 108. -1 ~ M) and beam weight generator 122, etc., the receiver 110 is a plurality of receive antennas (112-1 ~ 112-N), guard interval deleter 114, Discrete Fourier Transform Unit 116, a reception signal processor 118, and a feedback information generator 120.

The feedback information generator 120 estimates channel information to generate feedback information for beamforming a transmission signal using frequency correlation and spatial correlation from the estimated channel information, and generates the feedback information of the transmitter 100. And transmit it to the beamweight generator 122.

The beam weight generator 122 may receive feedback information from the feedback information generator 120 in the receiver 110, estimate a beam weight value from the feedback information, and beamform a transmission signal based on the estimated beam weight value. Of course, in order to generate feedback information for beamforming such a transmission signal, the receiver must accurately estimate the channel information.

2 is an exemplary view showing a detailed configuration of the feedback information generator 120 shown in FIG.

As shown in FIG. 2, the feedback information generator 120 according to the present invention includes a channel estimator 202, a converter 204, a quantizer 206, a feedback 208, and an antenna correlation matrix estimator 210. Multipath gain estimator 212 and primary channel component determiner 214.

The channel estimator 202 periodically estimates channel information, the converter 204 converts the estimated channel information by using a DFT matrix and a transmission antenna correlation matrix, and the quantizer 206 presets the channel information from the converted channel information. By generating a vector containing a number of elements and quantizing the vector, feedback information can be generated. The feedback information thus generated may then be transmitted to the beam weight generator in the transmitter via feedback 208.

In this case, the present invention can transmit the information for generating and estimating feedback information only when the channel characteristics change, rather than transmitting the information to the transmitter each time. This is because the amount of feedback information feedback to the transmitter is reduced to reduce the feedback burden. For sake.

First, the antenna correlation matrix estimator 210 may estimate the transmission antenna correlation matrix and the reception antenna correlation matrix based on the channel information of the channel estimator 202.

In addition, the multipath gain estimator 212 estimates the multipath gain of the channel based on the channel information of the channel estimator 202, and the main channel factor determiner 214 determines the number of main channel elements based on the multipath gain. The position information of the main channel element can be determined.

Accordingly, the feedback unit 208 may transmit the estimated transmission antenna correlation matrix, the number of primary channel elements, the location information of the primary channel elements, and the like before returning the channel information to the transmitter.

In addition, since the present invention generates feedback information based on MISO channel information, in order to apply MIMO channel information, the converter 204 converts MIMO channel information into MISO channel information using the first column vector of the received antenna correlation matrix. can do. Thereafter, the feedback information may be generated using the channel information thus converted in the same manner as described above.

Hereinafter, assume an OFDM system that transmits signals through K subcarriers using M transmit antennas. First, a case of using one receive antenna will be described by using an example of N receive antennas. Consider each of them separately.

라고 하는 경우, 공간 상관행렬 또는 안테나 상관행렬은 다음의 [수학식 1]과 같이 정의할 수 있다.First, the spatial correlation matrix and the frequency correlation matrix used in the present invention are defined as follows. channel vector h [k] = [h ₁ [k]. h _M [k]] ^T can be expressed as a vector of size (M × 1). Channels of size (M × K) containing channel information for k subcarriers

In this case, the spatial correlation matrix or the antenna correlation matrix may be defined as shown in Equation 1 below.

 [Equation 1]

Where Q = [ q ₁ ... q _M ] means a unitary matrix of size (M × M), and Λ = diag (λ ₁ ,…, λ _M ) is equal to {λ ₁ ,... , λ _M } means a diagonal matrix having a size of (M × M), and E {·} may mean an average operator.

인 경우 주파수 상관행렬은 다음의 [수학식 2]와 같이 정의할 수 있다.In addition, there are q independent paths in the time domain so that the gain of the i th path is reduced.

In this case, the frequency correlation matrix may be defined as shown in Equation 2 below.

[Equation 2]

인 DFT 행렬을 의미할 수 있다.Here, Σ = diag (σ ₁ ,…, σ _q , 0,…, 0) has the first q diagonal elements of {σ ₁ ,... , σ _q } and a diagonal matrix with the remaining Kq diagonal elements equal to 0, where F is the (i, j) th element

May mean a DFT matrix.

3 is a first exemplary diagram illustrating a method for generating feedback information according to an exemplary embodiment of the present invention.

As shown in FIG. 3, in the case of MISO (Multi Input Single Output) in which one receiving antenna exists, the receiver estimates MISO channel information (S310) and correlates the estimated MISO channel information H with the DFT matrix F and the transmitting antenna. Using the matrix Q can be converted as shown in Equation 3 below (S320).

&Quot; (3) "

The receiver may generate a vector formed by sequentially listing L elements of the converted MISO channel information H _w , that is, main channel elements, as shown in Equation 4 below (S330).

[Equation 4]

Here, [ A ] _{i, j} means (i, j) th element of matrix A , and π _s (l) and π _f (l) are index numbers that satisfy the following Equation 5 Can be.

[Equation 5]

In this case, L may be determined by the following Equation 6 by the main channel element determiner in the receiver.

&Quot; (6) "

은 i번째 다중경로의 이득, 상기

는 송신안테나 상관 행렬의 j번째 고유값, 상기 π_s(l) 및 π_f(l)는 주요 채널요소의 l번째 인덱스 번호, 그리고

는 양자화 코드북(Ω)의 특징에 따른 상수 값을 의미하며, 다음의 [수학식 7]과 같이 얻을 수 있다.Where M is the number of transmit antennas, K is the number of subcarriers, q is the number of multipaths, and

Is the gain of the i multipath,

Is the j-th eigenvalue of the transmit antenna correlation matrix, π _s (l) and π _f (l) are the l-th index number of the main channel element, and

Denotes a constant value according to the characteristics of the quantization codebook, and can be obtained as shown in Equation 7 below.

[Equation 7]

을 의미하며, e는 평균이 0인 i.i.d. 가우시안(gaussian) 랜덤 변수를 원소로 하는 크기가 L인 벡터를 각각 의미할 수 있다.here,

E may mean a vector having a size L having an iid Gaussian random variable having an average of 0 as an element.

In addition, the position information of the main channel elements is {(π _s (1), π _f (1)),... , (π _s (L), π _f (L))}.

를 기 설정된 양자화 코드북(Ω)을 이용하여 다음의 [수학식 8]과 같이 양자화하여 송신 빔포밍을 위한 궤환 정보를 생성하고(S340), 생성된 궤환 정보를 송신기에 궤환할 수 있다(S350).Since, the receiver is a vector

By using the predetermined quantization codebook (Ω) to quantize as shown in [Equation 8] below to generate feedback information for the transmission beamforming (S340), the feedback feedback can be fed back to the transmitter (S350) .

[Equation 8]

4 is a second exemplary diagram illustrating a method for generating feedback information according to an exemplary embodiment of the present invention.

As shown in FIG. 4, in the case of MIMO (Multi Input Multi Output) in which N receive antennas exist, when the channel matrix of the k-th subcarrier having a size (M × N) is H _MIMO [k], the reception antenna The correlation matrix can be defined as in Equation 9 below.

[Equation 9]

Where Q _r = [ q _r1 ... q _rN ] is a unitary matrix of size (N × N), Λ _r = diag (λ _{r, 1} ,…, λ _{r, N} ) is a diagonal matrix of size (N × N), and {λ _{r , 1} ,… , lambda _{r, N} } is lambda _{r, 1} ? ≧ λ _{r, N} ≧ 0.

The receiver estimates the MIMO channel information (S410) and uses the first MIMO vector q _r1 of the reception antenna correlation matrix Q _r as shown in [Equation 10] to calculate the MIMO channel information. The channel matrix may be converted into a MISO channel matrix having a size of (M × 1) (S420).

[Equation 10]

The receiver may obtain a matrix having a size of (M × K) for all subcarriers by using the generated MISO channel matrix h '[k] as shown in Equation 11 below.

[Equation 11]

Thereafter, the receiver may generate feedback information for transmission beamforming through the same process as the method described with reference to FIG. 3 using the generated channel information H (S430 to S460). That is, the receiver can convert the channel information H using a DFT matrix and a transmission antenna correlation matrix. Then, the receiver may generate a vector including the main L elements of the converted channel information, quantize the vector, generate feedback information, and feed it back to the transmitter.

5 is an exemplary diagram illustrating a method for beamforming a transmission signal according to an embodiment of the present invention.

As shown in FIG. 5, the transmitter receives feedback information (S510) and rearranges the major L elements at a corresponding position based on the received feedback information, and then zeros the remaining elements except for the major L elements. The converted channel information by input may be obtained as shown in Equation 12 below (S520).

At this time, the transmitter may rearrange the elements of the channel information based on the feedback information by using a known transmission antenna correlation matrix, the number of the main channel elements and the position information of the main channel elements.

[Equation 12]

는

의 l번째 원소를 의미할 수 있다.here,

Is

It can mean the lth element of.

The transmission antenna correlation matrix Q and the DFT matrix F may be inversely transformed as shown in Equation 13 below (S530).

[Equation 13]

Subsequently, the transmitter generates beam weight information w [k] of the k th subcarrier based on the inverse transformed channel information as shown in Equation 14 below (S540), and then attempts to transmit using the generated beam weight information. Data or a transmission signal can be beamformed (S550).

[Equation 14]

는

의 k번째 열 벡터를 의미하며,

는 벡터 놈(norm)을 의미할 수 있다.here,

Is

The k-th column vector of,

May mean a vector norm.

As described above, the present invention transmits channel information for a beamforming scheme to an transmitter in an OFDM system, and the receiver uses a frequency correlation and an antenna correlation to transmit a beam weighting value for the transmission beamforming with a smaller amount of feedback information than the conventional system. Can be generated. Accordingly, the present invention can more accurately estimate channel information when using the same feedback information amount, thereby improving the performance of the system.

The function of generating the multi-antenna beam disclosed herein can be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). do. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The channel information feedback apparatus and method for generating a multi-antenna beam in an OFDM system according to the present invention can be modified and applied in various forms within the scope of the technical idea of the present invention and are not limited to the above embodiments. In addition, the embodiments and drawings are merely for the purpose of describing the contents of the invention in detail, not intended to limit the scope of the technical idea of the invention, the present invention described above is common knowledge in the technical field to which the present invention belongs As those skilled in the art can have various substitutions, modifications, and changes without departing from the technical spirit of the present invention, it is not limited to the above embodiments and the accompanying drawings, of course, and not only the claims to be described below but also claims Judgment should be made including scope and equivalence.

1 is an exemplary view showing the configuration of a transceiver of an OFDM system according to an embodiment of the present invention.

2 is an exemplary view showing a detailed configuration of the feedback information generator 120 shown in FIG.

3 is a first exemplary diagram illustrating a method for generating feedback information according to an exemplary embodiment of the present invention.

4 is a second exemplary diagram illustrating a method for generating feedback information according to an exemplary embodiment of the present invention.

5 is an exemplary diagram illustrating a method for beamforming a transmission signal according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: transmitter

102: beam weight application unit

104: IDFT unit

106: guard section inserter

128: beamweight generator

108-1, 108-M: transmit antenna

110: receiver

114: protector delete

116: DFT section

118: reception signal processing unit

120: feedback information generator

112-1, 112-N: Receive Antenna

Claims (16)

A transformer for transforming the estimated channel information by using a Discrete Fourier Transform (DFT) matrix and a transmission antenna correlation matrix; A quantizer for generating a vector including a predetermined number of main channel elements of the converted channel information and quantizing the generated vector based on a quantization codebook to generate feedback information for transmission beamforming; And Feedback for feedback the generated feedback information to the transmitter Channel information feedback device for generating a multi-antenna beam comprising a. According to claim 1, The converter, Converting the estimated channel information into frequency information in the frequency domain from the frequency domain using the DFT matrix; Channel information feedback apparatus for generating a multi-antenna beam, characterized in that for performing the spatial orthogonal transformation of the channel information transformed into the time domain using the transmission antenna correlation matrix. The method according to claim 1 or 2, The quantizer is, A vector including a predetermined number of main channel elements of the converted channel information is generated, wherein the predetermined number L is Equation

Where M is the number of transmit antennas, K is the number of subcarriers, q is the number of multipaths, and

Is the gain of the i-th multipath of the channel,

Is the j th eigenvalue of the transmit antenna correlation matrix, π _s (l) and π _f (l) are the l th index number of the primary channel element, and

The channel information feedback apparatus for generating a multi-antenna beam, characterized in that each means a constant value according to the characteristics of the quantization codebook. The method of claim 3, The π _s (l) and π _f (l), Equation

Channel information feedback device for generating a multi-antenna beam, characterized in that obtained by. The method of claim 3, remind

Quot; Equation

Means a constant value according to the characteristics of the quantization codebook calculated by

And e is a vector having a size L having an iid Gaussian random variable having an average of 0 as an element. According to claim 1, The converter, If the estimated channel information is MIMO channel information, the MIMO channel information is converted into MISO channel information using a first column vector of a reception antenna correlation matrix. And converting the transformed MISO channel information by using a Discrete Fourier Transform (DFT) matrix and a transmit antenna correlation matrix. According to claim 1, An antenna correlation matrix estimator for estimating a transmission antenna correlation command and a reception antenna correlation matrix based on the estimated channel information; A multipath gain estimator for estimating a multipath gain based on the estimated channel information; And A main channel element determiner for determining the number of the main channel elements and their location information based on the estimated multipath gain The feedback unit further includes a channel information feedback for generating a multi-antenna beam, wherein the transmission antenna correlation matrix, the number of main channel elements, and their position information are fed back to the transmitter when channel characteristics change. Device. According to claim 1, The transmitter, Rearrange elements of channel information based on the feedback information, The rearranged channel information is inversely transformed using a transmission antenna correlation matrix and a DFT matrix. And generating beam weight information using the inversely transformed channel information and beamforming a transmission signal based on the information. Transforming the estimated channel information by using a Discrete Fourier Transform (DFT) matrix and a transmit antenna correlation matrix; Generating a feedback including a predetermined number of primary channel elements of the converted channel information and quantizing the generated vector based on a quantization codebook to generate feedback information for transmission beamforming; And Feedbacking the generated feedback information to a transmitter Channel information feedback method for generating a multi-antenna beam comprising a. The method of claim 9, The converting step, Converting the estimated channel information into frequency information in the frequency domain from the frequency domain using the DFT matrix; The channel information feedback method for generating a multi-antenna beam, characterized in that for performing the spatial orthogonal transformation of the channel information transformed in the time domain using the transmission antenna correlation matrix. The method of claim 9 or 10, The generating step, A vector including a predetermined number of main channel elements of the converted channel information is generated, wherein the predetermined number L is Equation

Where M is the number of transmit antennas, K is the number of subcarriers, q is the number of multipaths, and

Is the gain of the i-th multipath of the channel,

Is the j th eigenvalue of the transmit antenna correlation matrix, π _s (l) and π _f (l) are the l th index number of the primary channel element, and

The channel information feedback method for generating a multi-antenna beam, characterized in that each means a constant value according to the characteristics of the quantization codebook. The method of claim 11, wherein The π _s (l) and π _f (l), Equation

Channel information feedback method for generating a multi-antenna beam, characterized in that obtained by. The method of claim 11, wherein remind

Quot; Equation

Means a constant value according to the characteristics of the quantization codebook calculated by

And e is a vector having a size L having an iid Gaussian random variable having an average of 0 as an element. The method of claim 9, The converting step, If the estimated channel information is MIMO channel information, the MIMO channel information is converted into MISO channel information using a first column vector of a reception antenna correlation matrix. And converting the transformed MISO channel information using a Discrete Fourier Transform (DFT) matrix and a transmit antenna correlation matrix. The method of claim 9, Estimating a transmission antenna correlation command and a reception antenna correlation matrix based on the estimated channel information; Estimating a multipath gain based on the estimated channel information; And Determining the number of the main channel elements and their location information based on the estimated multipath gain The method may further include the step of returning the channel to the transmitter when the channel characteristics change, wherein the transmission antenna correlation matrix, the number of main channel elements, and their position information are fed back to the transmitter. Information feedback method. The method of claim 9, The transmitter, Rearrange elements of channel information based on the feedback information, The rearranged channel information is inversely transformed using a transmission antenna correlation matrix and a DFT matrix, And generating beam weight information using the inversely transformed channel information and beamforming a transmission signal based on the information.

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