KR20060097519A - Transmitting and Receiving Device and Method in Closed Loop Multiple Transceiver Antenna System - Google Patents

Abstract

The present invention relates to an apparatus and method for resolving power imbalance between antennas in a multiple transmit / receive antenna system using a closed loop scheme. In the transmitter according to the present invention, the transmitter apparatus may include a first operator for multiplying and transmitting a transmission vector to be transmitted and a beamforming matrix, and a multiplier for generating a plurality of antenna signals by multiplying the vector from the first operator by a predetermined phase rotation matrix. It consists of a two-operator.

Codebook, closed loop, MIMO, phase rotation matrix, unitary matrix, beamforming matrix,

Description

Transmitting and Receiving Apparatus and Method in Closed Loop Multiple Transmit and Receive Antenna System {APPARATUS AND METHOD FOR TRANSMITTING AND RECEIVING IN MIMO SYSTEM Based CLOSE LOOP}

1 is a diagram showing the configuration of a MIMO system using a closed loop scheme according to the prior art.

2 is a diagram illustrating a configuration of a MIMO communication system using a closed loop scheme according to an embodiment of the present invention.

3 is a graph showing a complementary cumulative distribution function (CCDF) of a peak to average power ratio (PAPR) of each antenna when the codebook according to the prior art and the codebook according to the present invention are used.

4 is a graph comparing link performance between a codebook according to the prior art and a codebook according to the present invention.

The present invention relates to a closed loop multiple input multiple output (MIMO) system, and more particularly, to an apparatus and a method for solving power unbalance between antennas in a closed loop MIMO communication system using a codebook.

)을 피드백 채널을 통해 송신기로 전송하여야 한다.In general, many systems use transmit beamforming to reduce received signal to noise ratio (SNR) or mean square error (MSE) of a received signal. However, in order to find an optimal beamforming vector or matrix, the receiver (or terminal) must perform an operation as shown in Equation 1 below.

) Shall be transmitted to the transmitter through the feedback channel.

은 미리 알고 있는 코드북(codebook) 중 선택된 빔포밍 벡터 혹은 매트릭스가 된다. 그리고 는 송신 안테나의 수를 나타내고,

은 수신 안테나의 수를 나타내며,

는 송수신 안테나 사이에 채널계수 매트릭스를 나타내고,

와

는 각각 신호와 잡음을 나타낸다. here,

Becomes a selected beamforming vector or matrix from among known codebooks. And Represents the number of transmit antennas,

Represents the number of receiving antennas,

Denotes a channel coefficient matrix between the transmit and receive antennas,

Wow

Denotes signal and noise, respectively.

In particular, in the case of a frequency division duplex (FDD) system, since the reciprocity of the channel cannot be used, quantized feedback information must be used. Currently, the IEEE 802.11e system determines the beamforming matrix using 3 bits and 6 bits of quantized feedback information.

For the sake of understanding, the beamforming matrix codebook currently used in IEEE802.16e will be described as an example.

Table 1 below shows some of the codebooks currently adopted in IEEE802.16e.

Index Column1 Column2 w1 0 0 One 0 0 One w2 -0.7201 + j0.3126 0.2483 + j0.2684 -0.2326 0.1898 + j0.5419 0.1898-j0.5419 0.7325 w3 -0.0659-j0.1371 -0.6283 + j0.5763 0.9537 0.0752 + j0.2483 0.0752-j0.2483 -0.4537 w4 -0.0063-j0.6527 0.4621 + j0.3321 0.1477 0.4394-j0.5991 0.4394 + j0.5991 0.3522 w5 0.7171-j0.3202 -0.2533-j0.2626 -0.2337 0.1951 + j0.5390 0.1951-j0.5390 0.7337 w6 0.4819 + j0.4517 0.2963 + j0.4801 0.1354 -0.7127-j0.1933 -0.7127 + j0.1933 0.3692 w7 0.0686 + j0.1386 0.6200-j0.5845 0.9522 0.0770 + j0.2521 0.0770-j0.2521 -0.4522 w8 -0.0054 + j0.6540 -0.4566-j0.3374 0.1446 0.4363-j0.6009 0.4363 + j0.6009 0.3554

In Table 1, columns 1 and 2 represent transport streams, and rows in each w represent transmit antennas. That is, the first row means antenna 1, the second row means antenna 2, and the third row means antenna 3. That is, Table 1 shows an example of three transmission antennas, two transport streams, and three bits of feedback information. The receiver sequentially calculates Equation 1 for the codebook shown in Table 1, that is, substitutes Equation 1 from beamforming matrices w1 to w8, and selects the beamforming matrix having the smallest value. Then, the index (index, 3 bits) for the selected beamforming matrix is fed back to the transmitter. Then, the transmitter multiplies the transmission vector by the beamforming matrix according to the index to perform beamforming. Through such beamforming, link performance is improved. Currently, IEEE802.16e employs a total of 19 different codebooks for two to four transmit antennas, one to four streams, and three and six bit feedback amounts.

However, as can be seen from Table 1, codebook beamforming, which is widely used at present, has a power imbalance problem in which power is concentrated on a specific antenna. That is, in Table 1, the receiver finds the most optimal w through the reception channel, but unfortunately, when w1 is selected, antenna 1 is not used at all. This problem exists not only in specific Table 1, but also in various cases (another codebook). In general, since the total transmission power is limited and the transmission power is divided and allocated for each antenna, there is a problem in that power is concentrated to antennas 2 and 3 in this case.

1 shows a configuration of a MIMO system using a closed loop method according to the prior art.

As shown, the transmitter comprises a code and modulator 101, a beamforming matrix determiner 102, a beamformer 103, a plurality of transmit antennas 104, 105, and the receiver comprises a plurality of receive antennas. Fields 106, 107, channel and receive symbol estimator 108, demodulation and decoder 109, and beamforming matrix selector 110.

Referring first to the transmitter, the code and modulator 101 encodes the transmitted data by a given coding scheme and modulates the encoded data by a given modulation scheme to generate complex symbols. The beamforming matrix selector 102 generates and outputs a beamforming matrix according to an index fed back from the receiver. The beamformer 103 transmits through the plurality of antennas 104 and 105 by multiplying the transmit vector (complex symbols) from the code and modulator 101 by the beamforming matrix from the beamforming matrix determiner 102. do.

,

)이 가산된 형태로 채널 및 수신심볼 추정기(108)로 입력된다. 상기 채널 및 수신심볼 추정기(108)는 채널추정을 통해 채널계수 매트릭스를 산출하고, 수신벡터와 상기 채널계수 매트릭스를 이용해 수신심볼을 추정하여 출력한다. 복조 및 복호기(109)는 상기 채널 및 수신심볼 추정기(108)로부터의 수신심볼들을 복조 및 복호하여 원래의 정보데이터로 복원한다. 한편, 빔포밍 매트릭스 선택기(110)는 상기 채널 및 수신심볼 추정기(108)로부터의 채널계수 매트릭스 및 현재 제안되어 있는 코드북을 가지고 상기 수학식 1의 연산을 수행하여 빔포밍 매트릭스를 선택하고, 상기 선택된 빔포밍 매트릭스에 대한 인덱스를 송신기로 피드백한다.Next, looking at the receiver, the signal received through the plurality of receivers (106, 107) is noise (

,

) Is input to the channel and receive symbol estimator 108 in an added form. The channel and receive symbol estimator 108 calculates a channel coefficient matrix through channel estimation, estimates and outputs a received symbol using the received vector and the channel coefficient matrix. The demodulator and decoder 109 demodulates and decodes the received symbols from the channel and receive symbol estimator 108 to restore the original information data. Meanwhile, the beamforming matrix selector 110 selects a beamforming matrix by performing the calculation of Equation 1 with the channel coefficient matrix from the channel and the reception symbol estimator 108 and the currently proposed codebook. The index for the beamforming matrix is fed back to the transmitter.

However, as described above, since the currently proposed codebook includes beamforming matrices in which power is concentrated on a specific antenna, there is a need for a method for solving the power imbalance problem between antennas.

Accordingly, an object of the present invention is to provide an apparatus and method for solving a power imbalance between antennas and reducing peak power in a multiple input multiple output (MIMO) communication system using a closed loop scheme.

Another object of the present invention is to eliminate peak condensation and reduce peak power by multiplying a transmission vector by a beamforming matrix and then multiplying a predetermined phase rotation matrix in a MIMO communication system using a closed loop scheme. To provide an apparatus and method for.

It is still another object of the present invention to eliminate a phenomenon in which power is concentrated on a specific antenna by multiplying a transmission vector and a beamforming matrix in a closed loop MIMO communication system using a codebook, and reducing peak power. To provide an apparatus and method for.

It is still another object of the present invention to eliminate the phenomenon that power is concentrated on a specific antenna by multiplying a transmission vector by a beamforming matrix and then multiplying a beamforming matrix in a closed loop MIMO communication system using a codebook and reducing peak power. To provide an apparatus and method for.

Another object of the present invention is to reduce peak power and eliminate power concentrating on a specific antenna by multiplying a transmission vector by a beamforming matrix and then multiplying a Vandermonde matrix in a closed loop MIMO communication system using a codebook. An apparatus and method are provided.

Another object of the present invention is to eliminate the phenomenon that the power is concentrated in a specific antenna by multiplying a transmission vector by a beamforming matrix and then multiplying a matrix of a fast fourier transform (FFT) form in a closed loop MIMO communication system using a codebook. An apparatus and method for removing peak power are provided.

According to a first aspect of the present invention for achieving the above objects, a transmitter apparatus in a multiple transmit and receive antenna system, a first operator for multiplying and outputs a transmission vector to be transmitted and a beamforming matrix, a vector and a predetermined phase from the first operator And a second operator for multiplying the rotation matrix to generate a plurality of antenna signals.

(

는 송신안테나의 개수) 유니터리(unitary) 매트릭스인 것을 특징으로 한다.Preferably, the phase rotation matrix is

(

Is the number of transmit antennas) and a unitary matrix.

According to a second aspect of the present invention, a receiver apparatus in a multiple transmit / receive antenna system includes a channel estimator for generating a channel coefficient matrix by channel estimation using signals received through a plurality of receiving antennas, and a channel coefficient matrix from the channel estimator. A beamforming matrix selector which searches an codebook of new beamforming matrices multiplied by a beamforming matrix and a predetermined phase rotation matrix to select an optimal beamforming matrix, and feeds back index information on the selected beamforming matrix to a transmitter. Characterized in that it comprises a.

(

는 송신안테나의 개수) 유니터리(unitary) 매트릭스인 것을 특징으로 한다.Preferably, the phase rotation matrix is

(

Is the number of transmit antennas) and a unitary matrix.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention relates to a technique for multiplying a transmission vector by a beamforming matrix and then multiplying a predetermined phase rotation matrix in order to solve a power imbalance problem between antennas in a closed loop multiple input multiple output (MIMO) communication system using a codebook. Let's look at it.

2 shows a configuration of a MIMO communication system using a closed loop scheme according to an embodiment of the present invention.

As shown, the transmitter according to the present invention comprises a code and modulator 201, a beamforming matrix determiner 202, a beamformer 203, a plurality of transmit antennas 204 and 205, and a receiver A plurality of receive antennas 206 and 207, a channel and receive symbol estimator 208, a demodulator and decoder 209, and a beamforming matrix selector 210 are configured. In this case, the beamformer 203 includes a W (beamforming matrix) multiplier 213 and an R (phase rotation matrix) multiplier 223 according to a feature of the present invention.

,

)이 가산된 형태로 채널 및 수신심볼 추정기(208)로 입력된다. 상기 채널 및 수신심볼 추정기(208)는 채널추정을 통해 채널계수 매트릭스를 산출하고, 수신벡터와 상기 채널계수 매트릭스를 이용해 수신심볼을 추정하여 출력한다. 여기서, 상기 수신심볼 추정 알고리즘으로는 ZF(Zero-Forcing), MMSE(minimum mean-square error)알고리즘 등을 사용할수 있다. 복조 및 복호기(209)는 상기 채널 및 수신심볼 추정기(208)로부터의 수신심볼들을 복조 및 복호하여 원래의 정보데이터로 복원한다. Referring first to the receiver, the signal received through the plurality of receivers 206, 207 is noise (

,

) Is input to the channel and receive symbol estimator 208 in an added form. The channel and receive symbol estimator 208 calculates a channel coefficient matrix through channel estimation, estimates and outputs a received symbol using the received vector and the channel coefficient matrix. Here, ZF (Zero-Forcing), MMSE (minimum mean-square error) algorithm, etc. may be used as the reception symbol estimation algorithm. The demodulator and decoder 209 demodulates and decodes the received symbols from the channel and receive symbol estimator 208 to restore the original information data.

Meanwhile, the beamforming matrix selector 210 according to the present invention selects a beamforming matrix by performing the calculation of Equation 1 with the channel coefficient matrix from the channel and the reception symbol estimator 208 and the codebook according to the present invention. The index of the selected beamforming matrix is fed back to the transmitter. Equation 1 shows one of various algorithms for selecting a beamforming matrix, and may select a beamforming matrix using another algorithm.

에 소정의 위상회전 매트릭스

을 곱한 새로운 빔포밍 매트릭스

로 구성된 코드북이다. 본 발명에 따른 코드북은

에 대한 데이터를 가지고 있을수 있 고, 다른 예로 기존의 빔포밍 매트릭스와 해당 위상회전 매트릭스

를 별도로 가지고 있을 수 있다. 따라서, 송신기로 피드백되는 정보는 상기

에 대한 인덱스 정보일수도 있고, 상기

에 대한 인덱스 정보일수 있다. 각각의 경우에 대한 상기 위상회전 매트릭스는 이후 수식을 통해 상세히 살펴보기로 한다.Here, the codebook according to the present invention is a beamforming matrix that has been proposed previously.

Predetermined phase rotation matrix

New beamforming matrix multiplied by

Codebook consisting of Codebook according to the present invention

As another example, the existing beamforming matrix and the corresponding phase rotation matrix may be included.

You may have a separate Therefore, the information fed back to the transmitter is

May be index information for

It may be index information about. The phase rotation matrix for each case will be described in detail through the following equation.

Next, referring to the transmitter, the code and modulator 201 encodes the transmitted data by a given coding scheme and modulates the encoded data by a given modulation scheme to generate complex symbols. In this case, a convolutional code, a turbo coder, a complementary turbo code, a low density parity check (LDPC) code, or the like may be used as a coding method. In the modulation scheme, BPSK (Binary Phase Shift Keying), which maps one bit (s = 1) to one signal point (complex signal), and maps two bits (s = 2) to one complex signal Quadrature Phase Shift Keying (QPSK), 8QAM (8ary Quadrature Amplitude Modulation) mapping three bits (s = 3) to one complex signal, and 16QAM mapping four bits (s = 4) to one complex signal 64QAM which maps six bits (s = 6) to one complex signal can be used.

와 위상회전 매트릭스

를 생성하여 빔형성기(203)로 출력한다. Beamforming matrix selector 202 is a beamforming matrix according to the index information fed back from the receiver

And phase rotation matrix

Is generated and output to the beamformer 203.

를 곱하여 출력한다. 상기 빔형성기(203)의 R곱셈기(223)는 상기 W곱셈기(213)로부터의 벡터와 상기 빔포밍 매트릭스 결정기(202)로부터의 위상회전 매트릭스

을 곱하여 복수의 송신안테나들(204, 205)을 통해 송신한다. 결론적으로, 송신벡터에 본 발명에 따른 새로운 빔포밍 매트릭스

을 곱하여 송신한다.The W multiplier 213 of the beamformer 203 transmits (complex symbols) from the code and modulator 201 and the beamforming matrix from the beamforming matrix determiner 202.

Multiply by The R multiplier 223 of the beamformer 203 is a vector from the W multiplier 213 and a phase rotation matrix from the beamforming matrix determiner 202.

Multiply by and transmit through a plurality of transmission antennas (204, 205). In conclusion, the new beamforming matrix according to the present invention in the transmission vector

Multiply by and send.

에 대해 상세히 살펴보기로 한다.Then, the phase rotation matrix proposed by the present invention here

Let's take a closer look at.

은 링크 성능에 전혀 영향을 미치지 않는다. 즉, 최적으로 설계된 코드북의 성질을 변화시키지 않는다. 또한, 각 안테나에 대한 PAPR(Peak to Average Power Ratio)도 변화지 않는다. 그러나, 본 발명에 따른 위상회전 매트릭스

을 적용하면, 종래기술에서 언급했던 안테나간 전력 불균형 문제 및 첨두 전력 문제를 해결할수 있다. Phase rotation matrix proposed in the present invention

Does not affect link performance at all. In other words, it does not change the nature of the optimally designed codebook. In addition, the peak to average power ratio (PAPR) for each antenna does not change. However, the phase rotation matrix according to the present invention

By applying this, it is possible to solve the power unbalance problem and the peak power problem between antennas mentioned in the prior art.

는 다음과 같은 성질을 만족하여야 한다.Phase Rotation Matrix in order not to change the currently proposed codebook properties

Must satisfy the following properties.

는 유니터리 매트릭스(unitary matrix)이어야 한다.Phase rotation matrix

Must be a unitary matrix.

Therefore, any unitary matrix can be used as the phase rotation matrix according to the present invention. However, considering the complexity of the implementation, it is preferable to use the following three examples.

<Example using Walsh Hadamard Matrix>

가 '2'인 경우에는 하기 수학식 2와 같은 2×2 하다마드 매트릭스를 위상회전 매트릭스로 사용한다.Number of transmit antennas

Is 2, a 2x2 Hadamard matrix is used as the phase rotation matrix.

가 '4'인 경우에는 하기 수학식 3과 같은 4×4 하다마드 매트릭스를 위상회전 매트릭스로 사용한다.Meanwhile, the number of transmitting antennas

Is 4, a 4x4 Hadamard matrix is used as the phase rotation matrix.

<Example using Vandermonde matrix>

에 따라 하기 수학식 4와 같은

Vandermonde 매트릭스를 위상 회전 매트릭스로 사용할수 있다.Number of transmit antennas

According to Equation 4 below

The Vandermonde matrix can be used as the phase rotation matrix.

이다.here,

to be.

When the Vandermonde matrix is used, a unitary matrix can be freely generated for any number of transmit antennas.

가 '2'인 경우에는 하기 수학식 5와 같은 2ㅧ2 Vandermonde 매트릭스를 위상 회전 매트릭스로 사용한다. For example, the number of transmit antennas

If is '2' is used 2 × 2 Vandermonde matrix as shown in the equation (5) as the phase rotation matrix.

가 '3'인 경우에는 하기 수학식 6과 같은 3×3 Vandermonde 매트릭스를 위상 회전 매트릭스로 사용한다.Meanwhile, the number of transmitting antennas

Is 3, a 3x3 Vandermonde matrix as shown in Equation 6 is used as the phase rotation matrix.

<Example using matrix of FFT format>

이다.here,

to be.

Even when using the fast Fourier transform (FFT) matrix, a unitary matrix can be freely generated for any number of transmit antennas.

은 다음의 코드북에 곱해져서 새로운 코드북을 형성한다. 다음의 코드북은 IEEE802.16e에 채택되어 있는 코드북이다. Phase rotation matrix made as above

Is multiplied by the following codebook to form a new codebook. The following codebook is a codebook adopted in IEEE802.16e.

을 곱하여 만들어진 새로운 코드북을 살펴보기로 한다. 예를들어, 전송 스트림이 1이고 피드백 양이 3비트인 경우 안테나 개수에 따른 새로운 코드북을 살펴보면 다음과 같다. 여기서, 송신 안테나 개수가 2, 4인 경우는 위상회전 행렬로 하다마드 매트릭스, 반데몬드 매트릭스 및 FFT 매트릭스를 모두 적용할수 있고, 송신 안테나의 개수가 3인 경우는 반데몬드 매트릭스와 FFT 매트릭스를 적용할수 있다.Then, here, the phase rotation matrix in the codebook

Let's look at a new codebook created by multiplying by. For example, if the transport stream is 1 and the feedback amount is 3 bits, the new codebook according to the number of antennas is as follows. Here, when the number of transmit antennas is 2, 4, the Hadamard matrix, the half-demon matrix, and the FFT matrix are all applicable to the phase rotation matrix, and when the number of transmit antennas is 3, the half-demon matrix and the FFT matrix are applicable. have.

<Transmit antenna 2, transmit stream 1, feedback amount 3 bits, Hadamard matrix application>

Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0,07071- 0.0000i 0.1513+ 0.1285i 0.6022+ 0.4279i 0.3510- 0.3746i 0.9885+ 0.0487i 0.7003+ 0.4766i 0.6976- 0.5063i -0.3882- 0.2461i Antenna 2 -0.7071- 0.0000i -0.9716+ 0.1285i -0.5208+ 0.4279i -0.7721- 0.3746i -0.1346+ 0.0487i 0.2351+ 0.4766i -0.0253- 0.5063i -0.8533- 0.2461i

<Transmit Antenna 2, Transmit Stream 1, Feedback Amount 3 Bits, Vandemon Matrix Application>

Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.7071 0.1805-0.1991i 0.2877 + 0.3313i 0.6775-0.4138i 0.8290 + 0.3363i 0.2263 + 0.6677i 0.9572-0.1203i -0.0323-0.6130i Antenna 2 0.7071 0.9424 + 0.1991i 0.8353-0.3313i 0.4455 + 0.4138i 0.2941-0.3363i 0.2389-0.6677i -0.2342 + 0.1203i 0.4975 + 0.6130i

<Tx antenna 3, transmit stream 1, feedback amount 3 bits, applying the vandemon matrix>

Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5774 0.3509- 0.2815i 0.4444+ 0.3855i -0.3981+ 0.0199i 0.2240+ 0.2832i 0.2389+ 0.5213i 0.1397- 0.3867i 0.9754-0.0304i Antenna 2 0.5774 0.6687+ 0.5198i 0.6334- 0.4512i 0.7689- 0.0569i -0.0844- 0.5255i 0.2079+ 0.1413i  -0.0633+ 0.4470i -0.1892+ 0.0655i Antenna 3 0.5774 -0.1535- 0.2383i -0.2118+ 0.0657i 0.4953+ 0.0370i 0.7264+ 0.2423i 0.4111- 0.6625i 0.7897- 0.0603i  0.0799- 0.0351i

<Transmission antenna 4, transmission stream 1, feedback amount 3 bits, Hadamard matrix application>

Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5000- 0.0000i 0.4313- 0.3250i -0.2151+ 0.2376i 0.2255- 0.4355i -0.0075+ 0.0653i 0.7890+ 0.4828i 0.3381- 0.2145i -0.2381+ 0.1905i Antenna 2 0.5000+ 0.0000i 0.5424+ 0.4829i 0.3581- 0.3843i 0.2226- 0.3906i 0.4039- 0.0163i 0.0004- 0.3003i -0.4813+ 0.2979i 0.2705+ 0.3124i Antenna 3 0.5000- 0.0000i -0.3231- 0.2417i -0.1172- 0.1050i 0.4355+ 0.3415i 0.3013+ 0.5825i 0.1137- 0.1296i 0.2457+ 0.0776i 0.6779- 0.5237i Antenna 4 0.5000+ 0.0000i 0.1054+ 0.0839 i 0.7302+ 0.2517i -0.1277+ 0.4846i 0.0582- 0.6315i -0.1472- 0.0529i 0.6534- 0.1610i 0.0457+ 0.0208i

3 is a complementary cumulative distribution function of a peak to average power ratio (PAPR) of each antenna when a codebook (WO (without) R) according to the prior art and a codebook (W (with) R) according to the present invention are used. ) Is a graph. As shown, regardless of which codebook is used, the PAPR can be seen to be unchanged. In other words, the codebook does not affect PAPR.

4 is a graph comparing link performance between a codebook WO (without) R according to the prior art and a codebook (W (with) R) according to the present invention. As shown, since both the codebook and the codebook of the present invention do not change the chordal distance between the codes, it can be seen that there is no change in performance even when using the codebook according to the present invention.

The simulation environment of FIGS. 3 and 4 is an environment using LDPC codes R = 1/2 and Red A 3km / h in a band AMC (Adaptive Modulation and Coding) subchannel defined in IEEE802.16e.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As described above, the present invention has the advantage of solving the power unbalance between antennas due to the use of the existing codebook in a closed loop MIMO system using a codebook. Moreover, the use of simple phase rotation matrices (eg Hadamard matrix, Vandermonde matrix) has the advantage of solving the power unbalance and peak power problems between antennas without complexity.

Claims (53)

A transmitter apparatus in a multiple transmit / receive antenna system, A first operator for multiplying and outputting a transmission vector to be transmitted and a beamforming matrix; And a second operator for generating a plurality of antenna signals by multiplying the vector from the first operator by a predetermined phase rotation matrix. The method of claim 1, And wherein the phase rotation matrix is a unitary matrix. The method of claim 1, And said phase rotation matrix is a Hadamard matrix. The method of claim 1, And said phase rotation matrix is a Vandermonde matrix. The method of claim 1, Wherein the phase rotation matrix is as shown in Equation (8).

here,

being. The method of claim 1, And said phase rotation matrix is a fast fourier transform (FFT) matrix. The method of claim 1, Wherein the phase rotation matrix is as in Equation (9).

here,

being. The method of claim 1, And the beamforming matrix is determined by searching a codebook with feedback information. The method of claim 8, And the feedback information is index information for a new beamforming matrix generated by multiplying the beamforming matrix and the phase rotation matrix. The method of claim 8, And the feedback information is index information for the beamforming matrix. The method of claim 1, The phase rotation matrix is

(

Is a number of transmit antennas) a unitary matrix. In the receiver device in a multiple transmit and receive antenna system, A channel estimator generating a channel coefficient matrix by channel estimation using signals received through a plurality of reception antennas; Search for a codebook consisting of new beamforming matrices multiplied by a beamforming matrix and a predetermined phase rotation matrix with a channel coefficient matrix from the channel estimator to select an optimal beamforming matrix, and index information for the selected beamforming matrix. And a beamforming matrix selector for feeding back to the transmitter. The method of claim 12, And wherein the phase rotation matrix is a unitary matrix. The method of claim 12, And said phase rotation matrix is a Hadamard matrix. The method of claim 12, And said phase rotation matrix is a Vandermonde matrix. The method of claim 12, The phase rotation matrix is characterized in that the following equation (10).

here,

being. The method of claim 12, And said phase rotation matrix is a fast fourier transform (FFT) matrix. The method of claim 12, Wherein the phase rotation matrix is as shown in Equation 11 below.

here,

being. The method of claim 12, And the algorithm for searching the codebook is a minimum mean-square error (MMSE) algorithm. In the transmission method in a multiple transmit and receive antenna system, Generating a vector by multiplying a transmission vector to be transmitted by a beamforming matrix; Generating a plurality of antenna signals by multiplying the generated vector by a predetermined phase rotation matrix. The method of claim 20, And wherein the phase rotation matrix is a unitary matrix. The method of claim 20, And wherein said phase rotation matrix is a Hadamard matrix. The method of claim 20, And wherein said phase rotation matrix is a Vandermonde matrix. The method of claim 20, The phase rotation matrix is characterized by the following equation (12).

here,

being. The method of claim 20, Wherein said phase rotation matrix is a fast fourier transform (FFT) matrix. The method of claim 20, Wherein the phase rotation matrix is as shown in Equation 13.

here,

being. The method of claim 20, Wherein the beamforming matrix is determined by searching a codebook with feedback information. The method of claim 20, The feedback information is index information for a new beamforming matrix generated by multiplying the beamforming matrix and the phase rotation matrix. The method of claim 20, The feedback information is index information for the beamforming matrix. The method of claim 20, The phase rotation matrix is

(

Is a number of transmit antennas) a unitary matrix. A feedback method of a receiver in a multiple transmit / receive antenna system, Generating a channel coefficient matrix by channel estimation using signals received through a plurality of receiving antennas; Selecting an optimal beamforming matrix by searching a codebook composed of new beamforming matrices multiplied by a beamforming matrix and a predetermined phase rotation matrix with the channel coefficient matrix; And feeding back index information of the selected beamforming matrix to a transmitter. The method of claim 31, wherein And said phase rotation matrix is a unitary matrix. The method of claim 31, wherein And wherein said phase rotation matrix is a Hadamard matrix. The method of claim 31, wherein And wherein said phase rotation matrix is a Vandermonde matrix. The method of claim 31, wherein The phase rotation matrix is characterized by the following equation (14).

here,

being. The method of claim 31, wherein Wherein said phase rotation matrix is a fast fourier transform (FFT) matrix. The method of claim 31, wherein The phase rotation matrix is characterized by the following equation (15).

here,

being. The method of claim 31, wherein The algorithm for the codebook search is characterized in that the minimum mean-square error (MMSE) algorithm. A transmitter apparatus in a multiple transmit / receive antenna system, A generator for generating a matrix formed by the product of a predetermined beamforming matrix and a phase rotation matrix; And an operator for generating a plurality of antenna signals by multiplying a transmission vector to be transmitted and a matrix from the generator. The method of claim 39, And said phase rotation matrix is a Hadamard matrix. The method of claim 39, And said phase rotation matrix is a Vandermonde matrix. The method of claim 39, Wherein the matrix generated at the generator is determined by feedback information from a receiver. The method of claim 39, And when two transmission antennas, one transport stream, and one feedback amount are three bits, the matrix generated in the generator is one of the matrices (w1-w8) shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0,07071- 0.0000i 0.1513+ 0.1285i 0.6022+ 0.4279i 0.3510- 0.3746i 0.9885+ 0.0487i 0.7003+ 0.4766i 0.6976- 0.5063i -0.3882- 0.2461i Antenna 2 -0.7071- 0.0000i -0.9716+ 0.1285i -0.5208+ 0.4279i -0.7721- 0.3746i -0.1346+ 0.0487i 0.2351+ 0.4766i -0.0253- 0.5063i -0.8533- 0.2461i The method of claim 39, And when the transmit antenna 2, the transport stream 1, and the feedback amount are 3 bits, the matrix generated in the generator is one of the matrices (w1-w8) shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.7071 0.1805-0.1991i 0.2877 + 0.3313i 0.6775-0.4138i 0.8290 + 0.3363i 0.2263 + 0.6677i 0.9572-0.1203i -0.0323-0.6130i Antenna 2 0.7071 0.9424 + 0.1991i 0.8353-0.3313i 0.4455 + 0.4138i 0.2941-0.3363i 0.2389-0.6677i -0.2342 + 0.1203i 0.4975 + 0.6130i The method of claim 39, And when three transmission antennas, one transport stream, and one feedback amount are three bits, the matrix generated in the generator is one of the matrices (w1-w8) shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5774 0.3509- 0.2815i 0.4444+ 0.3855i -0.3981+ 0.0199i 0.2240+ 0.2832i 0.2389+ 0.5213i 0.1397- 0.3867i 0.9754-0.0304i Antenna 2 0.5774 0.6687+ 0.5198i 0.6334- 0.4512i 0.7689- 0.0569i -0.0844- 0.5255i 0.2079+ 0.1413i  -0.0633+ 0.4470i -0.1892+ 0.0655i Antenna 3 0.5774 -0.1535- 0.2383i -0.2118+ 0.0657i 0.4953+ 0.0370i 0.7264+ 0.2423i 0.4111- 0.6625i 0.7897- 0.0603i  0.0799- 0.0351i The method of claim 39, And when four transmission antennas, one transport stream, and one feedback amount are three bits, the matrix generated in the generator is one of the matrices (w1-w8) shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5000- 0.0000i 0.4313- 0.3250i -0.2151+ 0.2376i 0.2255- 0.4355i -0.0075+ 0.0653i 0.7890+ 0.4828i 0.3381- 0.2145i -0.2381+ 0.1905i Antenna 2 0.5000+ 0.0000i 0.5424+ 0.4829i 0.3581- 0.3843i 0.2226- 0.3906i 0.4039- 0.0163i 0.0004- 0.3003i -0.4813+ 0.2979i 0.2705+ 0.3124i Antenna 3 0.5000- 0.0000i -0.3231- 0.2417i -0.1172- 0.1050i 0.4355+ 0.3415i 0.3013+ 0.5825i 0.1137- 0.1296i 0.2457+ 0.0776i 0.6779- 0.5237i Antenna 4 0.5000+ 0.0000i 0.1054+ 0.0839 i 0.7302+ 0.2517i -0.1277+ 0.4846i 0.0582- 0.6315i -0.1472- 0.0529i 0.6534- 0.1610i 0.0457+ 0.0208i In the transmitter device of a multiple transmit and receive antenna system, A generator comprising a codebook consisting of new beamforming matrices multiplied by a beamforming matrix and a phase rotation matrix, the generator generating a new beamforming matrix based on feedback information from a receiver by searching the codebook; And an operator for generating a plurality of antenna signals by multiplying the transmission vector to be transmitted by the generated new beamforming matrix. The method of claim 47, And 2 transmission antennas, 1 transport stream, and 3 bits of feedback, the codebook is as shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0,07071- 0.0000i 0.1513+ 0.1285i 0.6022+ 0.4279i 0.3510- 0.3746i 0.9885+ 0.0487i 0.7003+ 0.4766i 0.6976- 0.5063i -0.3882- 0.2461i Antenna 2 -0.7071- 0.0000i -0.9716+ 0.1285i -0.5208+ 0.4279i -0.7721- 0.3746i -0.1346+ 0.0487i 0.2351+ 0.4766i -0.0253- 0.5063i -0.8533- 0.2461i The method of claim 47, And when the transmit antenna 2, the transport stream 1, and the feedback amount are 3 bits, the codebook is as shown in the following table. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.7071 0.1805- 0.1991i 0.2877+ 0.3313i 0.6775- 0.4138i 0.8290+ 0.3363i 0.2263+ 0.6677i 0.9572- 0.1203i -0.0323- 0.6130i Antenna 2 0.7071 0.9424+ 0.1991i 0.8353- 0.3313i 0.4455+ 0.4138i 0.2941- 0.3363i 0.2389- 0.6677i -0.2342+ 0.1203i 0.4975+ 0.6130i The method of claim 47, And the codebook is the following table when the three transmission antennas, the transport stream 1, and the feedback amount are 3 bits. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5774 0.3509- 0.2815i 0.4444+ 0.3855i -0.3981+ 0.0199i 0.2240+ 0.2832i 0.2389+ 0.5213i 0.1397- 0.3867i 0.9754-0.0304i Antenna 2 0.5774 0.6687+ 0.5198i 0.6334- 0.4512i 0.7689- 0.0569i -0.0844- 0.5255i 0.2079+ 0.1413i  -0.0633+ 0.4470i -0.1892+ 0.0655i Antenna 3 0.5774 -0.1535- 0.2383i -0.2118+ 0.0657i 0.4953+ 0.0370i 0.7264+ 0.2423i 0.4111- 0.6625i 0.7897- 0.0603i  0.0799- 0.0351i The method of claim 47, And the codebook is shown in the following table when the four transmit antennas, the transport stream 1, and the feedback amount are 3 bits. Index w1 w2 w3 w4 w5 w6 w7 w8 Antenna 1 0.5000- 0.0000i 0.4313- 0.3250i -0.2151+ 0.2376i 0.2255- 0.4355i -0.0075+ 0.0653i 0.7890+ 0.4828i 0.3381- 0.2145i -0.2381+ 0.1905i Antenna 2 0.5000+ 0.0000i 0.5424+ 0.4829i 0.3581- 0.3843i 0.2226- 0.3906i 0.4039- 0.0163i 0.0004- 0.3003i -0.4813+ 0.2979i 0.2705+ 0.3124i Antenna 3 0.5000- 0.0000i -0.3231- 0.2417i -0.1172- 0.1050i 0.4355+ 0.3415i 0.3013+ 0.5825i 0.1137- 0.1296i 0.2457+ 0.0776i 0.6779- 0.5237i Antenna 4 0.5000+ 0.0000i 0.1054+ 0.0839 i 0.7302+ 0.2517i -0.1277+ 0.4846i 0.0582- 0.6315i -0.1472- 0.0529i 0.6534- 0.1610i 0.0457+ 0.0208i The method of claim 47, And said phase rotation matrix is a Hadamard matrix. The method of claim 47, And said phase rotation matrix is a Vandermonde matrix.

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