KR20100056304A - Precoding apparatus and method for orthogonalized spatial multiplexing system - Google Patents

Abstract

PURPOSE: A precoding device and a method thereof are provided to improve the performance of a closed loop MIMO(Multiple Input Multiple Output) system with the low calculation complexity and little feedback information. CONSTITUTION: A feedback processor(180) uses channel state information from a receiver to decide a first precoding matrix and a second precoding matrix. A first precoding unit(140) uses the first precoding matrix which was decided in the feedback processor to maximize the Euclid minimum distance. A second precoding unit(150) uses a second precoding matrix which was decided in the feedback processor to make the real number part and the imaginary number part within a first symbol cross each other at right angles.

Description

Pre-processing apparatus and method of orthogonal space multiplexing system {PRECODING APPARATUS AND METHOD FOR ORTHOGONALIZED SPATIAL MULTIPLEXING SYSTEM}

The present invention relates to a preprocessing apparatus and method for an orthogonal spatial multiplexing system, and more particularly, to a preprocessing apparatus and method for an orthogonal spatial multiplexing system in a closed loop multiple input and output wireless communication.

As wireless communication services become more popular, users using code division multiple access (CDMA) and personal communication systems (PCS) mobile communication services increase over time, while frequency, etc. Communication resources are limited, providing high quality wireless communication services to many users. In order to solve this problem, a multi-input multi-output using a plurality of antennas in a transmitter and a receiver is not a single input single output (SISO) method using a single antenna in a transmitter and a receiver. , A technology for applying a MIMO scheme to a wireless communication service has been developed. Multiple input / output technology can obtain more diversity gain and multiple transmission gain than limited input / output technology in limited communication resources.

A wireless communication system (hereinafter, referred to as a 'MIMO system') to which a multiple input / output method is applied can be classified into an open loop MIMO system and a closed loop MIMO system according to whether or not channel state information is feedback. Can be. Closed loop MIMO system has an advantage of improving the capacity and the average error rate of the system by using the channel state information feedback from the receiving device. Conventional closed loop MIMO systems employ a method based on singular value decompositon (SVD) of a channel matrix. However, the singular value decomposition method has high computational complexity and feedback overhead. Recently, a method of reducing the amount of feedback of channel state information and using system resources more efficiently has been studied. Orthogonalized Spatial Multiplexing (OSM) techniques that ensure orthogonality between symbols transmitted by phase rotation in devices are being actively studied.

This orthogonal spatial multiplexing technique has the advantage of improving the performance of a closed loop MIMO system with low computational complexity and a small amount of feedback information.

An object of the present invention is to provide a preprocessing apparatus and method for an orthogonal spatial multiplexing system capable of improving the performance of a closed loop MIMO system while having low computational complexity and a small amount of feedback information.

In order to solve the above technical problem, a preprocessing apparatus of an orthogonal spatial multiplexing system according to an exemplary embodiment of the present invention includes a feedback processor configured to determine a first preprocessing matrix and a second preprocessing matrix by using channel state information from a receiving apparatus. A first preprocessor performing an operation to maximize a Euclidean minimum distance using the first preprocessing matrix determined by the processor, and a real part and an imaginary part in a first symbol using the second preprocessing matrix determined by the feedback processor It includes a second line processor for performing the operation to have orthogonality.

이며, 상기

는

이고, 상기

는

이며, 상기

와

는 상기 채널 상태 정보로부터 결정될 수 있다.The first preprocessing matrix is

And said

Is

And

Is

And said

Wow

May be determined from the channel state information.

와

의 값으로 결정될 수 있다.When the modulation scheme is 4-QAM (Quadrature Amplitude Modulation), the channel state information includes one bit information, and any one of two pairs of predetermined values according to the one bit information is selected.

Wow

It can be determined by the value of.

와

의 값으로 결정될 수 있다.When the modulation scheme is 16-QAM, the channel state information includes two bits of information, and any one of four pairs of predetermined values according to the two bits of information is determined.

Wow

It can be determined by the value of.

은

이고, 상기

은 상기 채널 상태 정보에 포함될 수 있다.The second preprocessing matrix is And said

silver

And

May be included in the channel state information.

The feedback processor may further determine a third preprocessing matrix using the channel state information, and perform a calculation to perform orthogonality between the first symbols by using the third preprocessing matrix determined by the feedback processor. It may include.

이며, 상기

는 상기 채널 상태 정보에 포함될 수 있다.The third preprocessing matrix is

And said

May be included in the channel state information.

및

를 포함하고, 상기 제2 심벌은 및

를 포함하며, 상기 심벌 변환부는 상기 심벌

의 실수부를 상기 심벌

의 실수부로, 상기 심벌

의 실수부를 상기 심벌

의 허수부로 변환하고, 상기 심벌

의 허수부를 상기 심벌

의 실수부로, 상기 심벌

의 허수부를 상기 심벌

의 허수부로 변환할 수 있다.A mapping unit for converting a bit stream into a second symbol, and a symbol converter for converting the second symbol into the first symbol, wherein the first symbol is

And

The second symbol includes And

Includes, the symbol conversion unit the symbol

The real part of the symbol

As the real part of the symbol

The real part of the symbol

Convert to the imaginary part of

The imaginary part of the symbol

As the real part of the symbol

The imaginary part of the symbol

Can be converted to an imaginary part of.

In a preprocessing method of an orthogonal spatial multiplexing system according to another aspect of the present invention, determining a first preprocessing matrix and a second preprocessing matrix using channel state information from a receiving apparatus, wherein the first preprocessing matrix determined in the determining step Performing an operation to maximize the Euclidean minimum distance by using and performing an operation such that the real part and the imaginary part in a first symbol are orthogonal to each other using the second preprocessing matrix determined in the determining step. do.

As described above, the apparatus and method for preprocessing an orthogonal spatial multiplexing system according to the present invention can improve performance of a closed loop MIMO system while having low computational complexity and a small amount of feedback information.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

First, a transmitter including a preprocessor of an orthogonal spatial multiplexing system according to an embodiment of the present invention will be described in detail with reference to FIG. 1.

1 is a block diagram illustrating a transmission apparatus of an orthogonal spatial multiplexing system according to an embodiment of the present invention.

The transmission apparatus according to the embodiment of the present invention includes a bit converter 110, a plurality of mapping units 120 and 125, a symbol converter 130, a first preprocessor 140, a second preprocessor 150, The third preprocessor 160, a plurality of transmit antennas 170 and 175, and a feedback processor 180 are included. Here, the number of mapping units 120 and 125 and the number of transmitting antennas 170 and 175 are implemented to be the same. Hereinafter, it will be assumed that two mapping units 120 and 125 and two transmitting antennas 170 and 175 exist. However, for convenience of explanation, the description will be mixed with two or more general cases as necessary. The preprocessing apparatus according to the embodiment of the present invention includes the first to third preprocessing units 140, 150, and 160 in a narrow sense, but in a broad sense, the bit converter 110, the mapping units 120, 125, and the symbol transform. The unit 130 may further include.

The bit converter 110 converts a bit stream that is serially input into a plurality of parallel streams according to the number of the mapping units 120 and 125 and sends them to the mapping units 120 and 125. Each parallel stream is generated by cutting the serial bit stream by a predetermined number of bits corresponding to the modulation levels of the mapping units 120 and 125. In this case, the modulation level is determined according to the modulation scheme used in the mapping units 120 and 125. For example, if the number of mapping units 120 and 125 is two and the modulation scheme is 16-QAM, the serially input bit stream may be converted into two parallel bit streams in units of 4 bits. That is, if the serially input bit stream is '01000010', it may be converted into two parallel bit streams of '0100' and '0010' by 4 bits.

을 생성하고, 매핑부(125)는 심벌

을 생성한다.The mapping units 120 and 125 convert the parallel bit stream provided from the bit converter 110 into a complex symbol by using quadrature amplitude modulation (QAM). The mapping unit 120 or 125 converts the bit stream into symbols using 4-bit units using the 16-QAM scheme and converts the bit stream into symbols using the 2-QAM scheme according to the modulation level. can do. For example, if a 16-QAM scheme is used and the bit streams are '0100' and '0010', they may be converted into complex symbols '-1-j * 3' and '-3 + j * 3', respectively. . Of course, the mapping units 120 and 125 may use other modulation schemes such as quadrature phase shift keying (QPSK), instead of the quadrature amplitude modulation scheme. The mapping unit 120 is a symbol

To generate, and the mapping unit 125 is a symbol

.

In the following description, normal characters are scalars, bold lowercase letters are vectors, and bold uppercase letters are matrices. For complex variables, add a bar to the top of the variable.

과

을 이용하여 심벌

과

으로 변환하며 이를

으로 나타내기로 한다.The symbol converter 300 is a symbol provided from the mapping unit 120, 125 as shown in Equation 1 below.

and

Symbol using

and

And convert it to

It is represented by.

의 실수부가 심벌

의 실수부로 심벌

의 실수부가 심벌

의 허수부로 변환되고, 심벌

의 허수부가 심벌

의 실수부로 심벌

의 허수부가 심벌

의 허수부로 변환된다.I.e. symbol

Real part of the symbol

The symbol of the real part of

Real part of the symbol

Converted to an imaginary part of

Imaginary symbol of

The symbol of the real part of

Imaginary symbol of

Is converted to the imaginary part of.

)를 최대화시키며, 제2 선처리부(150)는 직교 공간 다중화 시스템의 심벌(

) 내의 실수부 및 허수부를 서로 직교화시키며, 제3 선처리부(160)는 심벌(

)과 심벌(

)을 직교화시킨다. 제1 내지 제3 선처리부(140, 150, 160)는 각 선처리부에 대응하는 선처리 행렬을 가지고 연산을 수행하며, 제3 선처리부(160)에 의하여 최종 연산된 처리된 심벌을 송신 안테나(170, 175)를 통하여 전송한다.The first preprocessor 140 may have a Euclidean minimum distance between constellation points on an effective channel in a constellation.

), The second line processor 150 is a symbol of the orthogonal spatial multiplexing system.

The orthogonal part and the imaginary part in the orthogonal part are orthogonal to each other, and the third line processor 160 is a symbol (

) And a symbol (

Orthogonalize The first to third preprocessors 140, 150, and 160 perform calculations with preprocessing matrices corresponding to the preprocessors, and transmit the processed symbols finally calculated by the third preprocessor 160 to the transmit antenna 170. 175).

A receiving device (not shown) receives symbols from the transmitting antennas 170 and 175, extracts channel state information through an appropriate process, and sends them to the feedback processing unit 180 of the transmitting device. The feedback processor 180 determines a preprocessing matrix corresponding to the first to third preprocessors 140, 150, and 160 by using the channel state information from the receiver, and informs the preprocessor.

Orthogonal Space Multiplexing System without Preprocessing

First, an orthogonal space multiplexing system without the first preprocessor 140 and the second preprocessor 150 will be briefly described. This system is modeled as in Equation 2 below.

는 수신 장치(도시하지 않음)가 수신하는 복소 수신 신호이고,

는 송신 장치가 전송하려는 복소 송신 신호이며,

는

에 대한 유효 채널 행렬로서

를 나타낸다. 여기서

는 (i, j)의 원소가 j번째 송신 안테나와 i번째 수신 안테나 사이의 페이딩 계수(Fading Coefficient)를 나타내는 복소 채널 행렬이고,

는 두 번째 안테나에 적용되는 회전각을 나타낸다. 그리고

은 복소 가우시안 노이즈(Gaussian noise)를 나타낸다.here

Is a complex received signal received by a receiving device (not shown),

Is a complex transmit signal that the transmitting device wants to transmit,

Is

As the effective channel matrix for

Indicates. here

Is a complex channel matrix where the elements of (i, j) represent the fading coefficients between the j th transmit antenna and the i th receive antenna,

Represents the rotation angle applied to the second antenna. And

Denotes complex Gaussian noise.

Equation 2 above is a real-valued representation of Equation 3 below.

는

의 길이를 가지는 실수 칼럼 벡터(real column vector)로서 유효 실수 채널 행렬

의 i번째 칼럼을 나타낸다. 여기서,

은 수신 안테나의 개수를 나타낸다.here

Is

A real real channel vector with a length of real column vector

It represents the i th column of. here,

Denotes the number of receive antennas.

값에 관계없이, 칼럼 벡터

과

이 직교하고

와

이 직교함을 알 수 있다. 또한 모든

값에 대해

이 성립 하는 것을 알 수 있다. 여기서

과

가 직교하고

와

가 직교하면, 유효 실수 채널 행렬

는 직교성을 가지게 된다.In [Equation 3]

Column vector, regardless of the value

and

Is orthogonal

Wow

You can see this orthogonality. Also all

About the value

You can see that this holds true. here

and

Is orthogonal

Wow

Is orthogonal, the effective real channel matrix

Is orthogonal.

과

가 직교하고

와

가 직교하는 회전각

는 아래의 [수학식 4]에 의해 결정된다.

and

Is orthogonal

Wow

Rotation angle orthogonal

Is determined by Equation 4 below.

는

이고,

는

이다.here

Is

ego,

Is

to be.

일 때 수신 장치에서 수신되는 심벌

과

는 아래의 [수학식 5]에 의해 추정할 수 있다.And rotation angle

Symbol received at the receiving device when

and

Can be estimated by Equation 5 below.

는

의 크기를 가지는 성좌점(constellation)을 나타낸다.here

Is

It represents a constellation having the size of.

Orthogonal Space Multiplexing System with Preprocessing According to the Present Invention

Next, an orthogonal spatial multiplexing system to which line processing is applied according to the present invention will be described. An orthogonal spatial multiplexing system according to an embodiment of the present invention may be represented in a form in which precoding is applied to [Equation 3], and may be modeled as in Equation 6 below.

는 수신 장치(도시하지 않음)가 수신하는 신호이고,

는 송신 장치가 전송하려는 신호이며,

는

에 대한 유효 채널 행렬로서 위에서 설명한

과 동일한 행렬이다. 그리고

는 4Ⅹ4 실수 선처리 행렬을 나타내고, 아래의 [수학식 7]과 같다.here

Is a signal received by a receiving device (not shown),

Is the signal that the transmitting device wants to transmit,

Is

As the effective channel matrix for

Is the same matrix as And

Denotes a 4Ⅹ4 real preprocessing matrix, as shown in Equation 7 below.

과

는 2Ⅹ2 실수 행렬이다.here

and

Is a 2Ⅹ2 real matrix.

)관점에서, 유효 채널 행렬

의 첫 번째와 두 번째 칼럼의 채널 품질은 유효 채널 행렬

의 세 번째와 네 번째 칼럼의 채널 품질과 동일하다. 따라서 실수 선처리 행렬

에 있는

과

는 동일한 행렬이다. 실수 선처리 행렬

는 아래의 [수학식 8]과 같이 3개의 2Ⅹ2 실수 행렬로 분해시킬 수 있다.Euclidean minimum distance (

From the point of view, the effective channel matrix

The channel quality of the first and second columns of is the effective channel matrix

Is equal to the channel quality of the third and fourth columns. So real preprocessing matrix

In

and

Is the same matrix. Real preprocessing matrix

Can be decomposed into three 2Ⅹ2 real matrices as shown in Equation 8 below.

은

로,

는

로,

는

로 선택할 수 있으며, 행렬

는 제1 선처리부(140)의 선처리 행렬에 대응하고, 행렬

는 제2 선처리부(150)의 선처리 행렬에 대응하며, 행렬

는 제3 선처리부(160)의 선처리 행렬에 대응한다.here

silver

in,

Is

in,

Is

Can be selected as

Corresponds to the preprocessing matrix of the first preprocessor 140, and

Corresponds to a preprocessing matrix of the second preprocessor 150, and the matrix

Corresponds to the preprocessing matrix of the third preprocessing unit 160.

Substituting Equation 8 above into Equation 6 can be expressed as Equation 9 below.

는

로,

는

로 표현할 수 있다.here

Is

in,

Is

.

은 아래의 [수학식 10]에 의해 추정할 수 있다.Symbol sent

Can be estimated by Equation 10 below.

는

와

를 이용하여 위의 [수학식 10]과 유사한 방법으로 추정할 수 있다.And transmitted symbol

Is

Wow

It can be estimated by using a method similar to Equation 10 above using.

,

및

를 구하기 위해 파라미터

,

및

를 결정하는 방법에 대해 도 2를 참고하여 설명한다.Preprocessing matrix

,

And

Parameter to find

,

And

A method of determining will be described with reference to FIG. 2.

2 is a view for explaining a method of determining a parameter value according to an embodiment of the present invention.

과

가 직교하도록 하는 파라미터

은 아래의 [수학식 11]에 의하여 결정할 수 있다.first

and

Parameters to make orthogonal

May be determined by Equation 11 below.

는

이고,

는

이다.

는

이

일 때 최대인 반면,

는

이

일 때 최대가 된다. 그러나

이 둘 중 어느 값을 가지더 라도 동일한 유클리드 최소거리(

)를 가지게 되므로

은 둘 중 어느 값을 가지더라도 상관없다. 이하

인 경우에 대하여 설명한다.here

Is

ego,

Is

to be.

Is

this

Is maximum when

Is

this

Is the maximum when But

Regardless of which value, the same Euclidean minimum distance (

Will have

Can be either value. Below

Will be described.

와

를 최적의 값으로 결정하기 위한 방법은 아래의 [수학식 12]와 같다.parameter

Wow

The method for determining the optimal value is as shown in Equation 12 below.

는 파라미터

와

로 이루어진 함수로서 유클리드 최소거리를 나타낸다. 그리고 파라미터

가

의 범위 내에 있을 때의 유클리드 최소거리(

)와 파라미터

가

의 범위 내에 있을 때의 유클리드 최소거리(

)는 서로 대칭적이기 때문에, 파라미터

를 결정하기 위한 검색범위를

의 범위 내로 제한할 수 있다.here

Is a parameter

Wow

It is a function consisting of the Euclidean minimum distance. And parameters

end

Euclidean minimum distance within the range of

) And parameters

end

Euclidean minimum distance within the range of

) Are symmetrical to each other, so

Search scope to determine

It can be limited in the range of.

와

는 변하기 때문에, 이하 변조 방식은 4-QAM 방식을 이용하는 것으로 가정하고 설명한다.Optimal parameters depending on the modulation method

Wow

Since is changed, the following modulation scheme is assumed to use a 4-QAM scheme.

과 같다고 가정하면, 위의 [수학식 6]으로부터 유효 채널에서 잡음이 없이 수신된 심벌은

,

,

및

과 같다는 것을 알 수 있다. 따라서 [수학식 12]는 아래의 [수학식 13]과 같이 표현할 수 있다.In the 4-QAM scheme, the real part and the imaginary part of the transmitted symbol are

Suppose that is equal to, the received symbol without noise in the effective channel from Equation 6

,

,

And

It can be seen that Therefore, Equation 12 may be expressed as Equation 13 below.

과

가 직교하면,

,

,

및

는 아래의 [수학식 14]와 같다.And

and

If is orthogonal,

,

,

And

Is shown in Equation 14 below.

)를 최대화하는 파라미터

와

를 결정하기 위해, 파라미터

와

의 범위인

과

를 도 2에 도시한 바와 같이 세 개의 영역(

,

,

)으로 분할한다. 그리고 각 영역(

,

,

)별 유클리드 최소거리(

)를 최대화하는 파라미터

와

를 결정하 고, 각 영역(

,

,

)별 결과를 통해 전체 영역에서 유클리드 최소거리(

)를 최대화하는 파라미터

와

를 결정할 수 있다. 여기서

는

를 나타내고,

을 최대화하는

을 선택하면,

이 성립한다는 것을 알 수 있다. 이하 각 영역별로 유클리드 최소거리(

)를 최대화하는 파라미터

와

의 값을 설명한다.Then, at the Euclidean minimum distance (

To maximize)

Wow

To determine the parameters

Wow

Which is the range of

and

As shown in FIG. 2, three regions (

,

,

Divide by) And each area (

,

,

Euclidean minimum distance by)

To maximize)

Wow

To determine each area (

,

,

) Results show that the Euclidean minimum distance (

To maximize)

Wow

Can be determined. here

Is

Lt; / RTI >

To maximize

If you select,

It can be seen that this holds true. Euclidean minimum distance for each region

To maximize)

Wow

Explain the value of.

영역

domain

가

의 범위 이내이고, 파라미터

가

의 범위 이내이면,

관계가 성립한다. 이 관계와 위의 [수학식 14]로부터 아래의 [수학식 15]가 성립함을 알 수 있다.parameter

end

Is within the range of

end

If within the range of,

The relationship is established. From this relationship and Equation 14 above, it can be seen that Equation 15 below holds.

와

에 관계없이 유클리드 최소거리(

)는

과 같다는 것을 알 수 있다. 파라미터

가 주어지면

는 파라미터

의 값에 따라 증가하는 함수이고, 파라미터

가 주어지면

는 파라미터

의 값에 따는 증가하는 함수이다. 따라서 영역(

)에서 유클리드 최소거리(

)를 최대화하는 파라미터

는

이고 파라미터

는

임을 알 수 있다.Parameters from Equation 15 above

Wow

Regardless of the Euclidean minimum distance (

)

It can be seen that parameter

Is given

Is a parameter

Function that increases with the value of

Is given

Is a parameter

It is an incrementing function depending on the value of. Therefore, the area (

At the Euclidean minimum distance (

To maximize)

Is

And parameters

Is

It can be seen that.

영역

domain

가

의 범위 이내이고 파라미터

가

의 범위 이내이면,

와

관계가 성립한다. 따라서 유클리드 최소거리(

)의 후보는

과

임을 알 수 있고, 유클리드 최소거리(

)는

가 성립할 때 최대임을 알 수 있다.parameter

end

Is within the range of

end

If within the range of,

Wow

The relationship is established. Therefore, at the Euclidean minimum distance (

) Candidates

and

You can see that the Euclidean minimum distance (

)

It can be seen that when is true.

를 풀기 위해 파라미터

를 아래의 [수학식 16]과 같이 표현할 수 있다.Expression above

To solve

Can be expressed as Equation 16 below.

Substituting [Equation 16] into [Equation 14] is shown in [Equation 17] below.

의 관점에서 다시 정리하면 아래의 [수학식 18]과 같다.Parameters of Equation 17

In summary, Equation 18 is shown below.

[Equation 18] is summarized as [Equation 19] below.

을 기준으로 정리하면 아래의 [수학식 20]과 같다.Equation 19

When summarized based on Equation 20 below.

)를 최대화하려면 파라미터

가 영역(

)의 경계에 있어야 함을 알 수 있다. 따라서 파라미터

는

와

중 하나의 값을 가지게 된다. 그리고 파라미터

는

와

중 하나의 값을 가지게 된다.From Equation 19 and Equation 20, the Euclidean minimum distance (

Parameter to maximize)

Is the area (

You should know that it should be at the boundary of). Thus the parameter

Is

Wow

It will have one of the values. And parameters

Is

Wow

It will have one of the values.

영역

domain

가

의 범위 이내이고 파라미터

가

의 범위 이내이면, 채널 행렬

의 첫 번째 칼럼의 크기는 두 번째 칼럼의 크기보다 더 작게 되어, 다른 영역(

,

)보다 유클리드 최소거리(

)의 최대값이 작다는 것을 알 수 있다. 따라서 영역(

)은 파라미터

와

를 결정하는 데 고려할 필요가 없다.parameter

end

Is within the range of

end

If within the range of

The size of the first column of is smaller than the size of the second column, so that other areas (

,

Euclidean minimum distance ()

We can see that the maximum value of) is small. Therefore, the area (

) Is a parameter

Wow

There is no need to consider in determining.

의 최적값

와

의 최적값

은 아래의 [수학식 21]과 같다.In summary, the parameters in 4-QAM

Optimal value of

Wow

Optimal value of

Is shown in Equation 21 below.

와

의 후보군은 단지 두 개 존재하는 것을 알 수 있다. 따라서

값만 결정되면 파라미터

와

를 결정할 수 있다.From Equation 21, the parameter in the 4-QAM method

Wow

It can be seen that there are only two candidate groups. therefore

If only the value is determined, the parameter

Wow

Can be determined.

와

를 결정하는 방법과 유사하게 16-QAM 방식에서도 최적의 파라미터를 결정할 수 있다. 16-QAM 방식에서 파라미터

의 최적값

와

의 최적값

은 아래의 [수학식 22]와 같다.And parameters in 4-QAM

Wow

Similar to the method for determining the optimal parameter in the 16-QAM scheme can be determined. Parameters in 16-QAM Method

Optimal value of

Wow

Optimal value of

Is shown in Equation 22 below.

와

를 결정하는 방법과 유사하게 M-QAM 방식에서도 파라미터를 결정할 수 있다. M-QAM 방식에서 유클리드 최소거리(

)를 최대화하는 파라미터

와

를 결정하는 데 아래의 [수학식 23]이 이용될 수 있다.Also, the parameters in 4-QAM method

Wow

Similar to the method for determining the parameters in the M-QAM method can be determined. Euclidean minimum distance in M-QAM

To maximize)

Wow

Equation 23 below can be used to determine.

값을 수신하여 [수학식 21] 및 [수학식 22]에 따라 파라미터

와

를 결정하고 이 값을 이용하여 [수학식 8]에 따라 선처리 행렬

을 결정하면 된다.The feedback processing unit 180 of the transmitter transmits the channel state information from the receiver.

Receive the value and set the parameter according to [Equation 21] and [Equation 22].

Wow

And use this value to preprocess the matrix according to Equation (8).

You just need to decide.

값 대신 한 개 또는 두 개의 비트 정보를 이용하여 선처리 행렬

을 결정할 수도 있다. [수학식 21]과 [수학식 22]에서

값에 따라 변동되는

변화량이 작기 때문에 파라미터

값을 1 또는

로 대치할 수 있으며, 이렇게 하더라도 실질적인 성능 저하는 거의 없다. 그 결과가 [표 1]에 표시되어 있다.

값이 변동됨에 따라 결정되는 (

,

)값이 4-QAM 시스템에서는 2개, 16-QAM에서는 4개이다. 그러므로 송신 장치로 실수값

를 피드백하는 대신에 4-QAM에서는 피드백 정보로서 한 개의 비트 정보가 요구되고, 16-QAM 시스템에서는 피드백 정보로서 두 개의 비트 정보가 요구된다. 수신 장치는

값에 대응하는 적절한 비트 정보를 송신 장치의 피드백 처리부(180)로 피드백하고, 피드백 처리부(180)는 해당 비트 정보에 대응하는 선처리 행렬

을 결정하면 된다. 이와 같이 함으로써 성능 저하 없이 피드백 정보의 양을 줄일 수 있다. 더욱이 선처리 행렬

을 연산에 의하여 산출하는 것이 아니라 미리 정해진 선처리 행렬 후보군에서 추출하기만 하면 되므로 연산 복잡도는 한층 낮아진다.Meanwhile

Preprocessing matrix using one or two bits of information instead of values

May be determined. In [Equation 21] and [Equation 22]

Depending on the value

Since the amount of change is small

Value is 1 or

It can be replaced with, and there is little practical performance deterioration. The results are shown in [Table 1].

As the value changes (

,

) Are two in the 4-QAM system and four in the 16-QAM system. Therefore, the real value to the sending device

In the 4-QAM, one bit information is required as feedback information, and two bit information is required as feedback information in the 16-QAM system. The receiving device

The appropriate bit information corresponding to the value is fed back to the feedback processor 180 of the transmitting apparatus, and the feedback processor 180 preprocesses the matrix corresponding to the bit information.

You just need to decide. In this way, the amount of feedback information can be reduced without degrading performance. Moreover, preprocessing matrix

Calculation complexity is further lowered by only extracting from a predetermined preprocessing matrix candidate group, rather than calculating by arithmetic.

인 경우에 대하여 설명하였으나,

인 경우도 지금까지 설명한 방법과 동일한 방법으로

와

을 추출할 수 있다. 그러나

값이 달라지면

값도 달라지고 따라서 [표 1]의

값과

값도 달라질 수 있다.So far in [Equation 11]

Has been described,

In the same way as described above

Wow

Can be extracted. But

If the value is different

The values are different and therefore

Value and

The value can also vary.

와 [수학식 11]의

을 더 포함한다. 피드백 처리부(180)는 수신된

에 의하여 선처리 행렬

를 결정하고, 수신된

에 의하여 선처리 행렬

를 결정한다.On the other hand, the channel state information of [Equation 4]

And of Equation 11

It includes more. The feedback processor 180 receives the

Preprocessing matrix by

, And received

Preprocessing matrix by

Determine.

With the preprocessing matrix determined as described above, the first to third preprocessing units 140, 150, and 160 perform arithmetic operation and transmit the final arithmetic processed symbols through the transmit antennas 170 and 175.

Next, a result of simulating the performance of the transmitting apparatus of the orthogonal spatial multiplexing system according to the embodiment of the present invention will be described with reference to FIG. 3.

3 is a graph for explaining the performance of the transmission apparatus of the orthogonal spatial multiplexing system according to an embodiment of the present invention.

일 때 신호대 잡음비는 9dB 개선됨을 알 수 있다. 한편 16-QAM 변조 방식인 경우 본 발명의 실시예에 따른 직교 공간 다중화 시스템의 송신 장치는 곡선 ③과 같은 성능을 가지며, 선처리 없는 시스템은 곡선 ④와 같은 성능을 가진다. 따라서 비트 에러율이

일 때 신호대 잡음비는 7.5dB 개선됨을 알 수 있다.3 is a graph showing the performance of the system. The horizontal axis represents a signal-to-noise ratio (SNR), and the vertical axis represents a bit error rate (BER). In the case of using the 4-QAM modulation scheme, the transmission apparatus of the orthogonal spatial multiplexing system according to the embodiment of the present invention has the performance as shown by the curve ①, and the system without the preprocessing as shown by the curve ②. Therefore, the bit error rate

It can be seen that the signal-to-noise ratio improves by 9dB. On the other hand, in the case of the 16-QAM modulation scheme, the transmission apparatus of the orthogonal spatial multiplexing system according to the embodiment of the present invention has the same performance as the curve ③, and the system without the preprocessing has the performance as the curve ④. Therefore, the bit error rate

It can be seen that the signal-to-noise ratio is improved by 7.5dB.

Next, a line processing method of an orthogonal spatial multiplexing system according to an embodiment of the present invention will be described with reference to FIG. 4.

4 is a flowchart illustrating a line processing method of an orthogonal spatial multiplexing system according to an embodiment of the present invention.

과

을 생성한다. 물론 송신 장치는 직교 진폭 변조 방식(QAM)이 아니라 직교 위상 편이 변조(QPSK) 등의 다른 변조 방식을 이용할 수도 있다. 그리고 송신 장치는 심벌

과

을 이용하여 심벌

과

으로 변환한다(S430). 심벌

의 실수부가 심벌

의 실수부로 심벌

의 실수부가 심벌

의 허수부로 변환되고, 심벌

의 허수부가 심벌

의 실수부로 심벌

의 허수부가 심벌

의 허수부로 변환된다.First, the transmitting apparatus according to an embodiment of the present invention converts a serially input bit stream into a plurality of parallel bit streams based on a modulation level (S410). Thereafter, the transmitting apparatus converts the parallel bit stream into a complex symbol using a quadrature amplitude modulation (QAM) (S420).

and

. Of course, the transmitting device may use other modulation schemes such as quadrature phase shift keying (QPSK) instead of quadrature amplitude modulation (QAM). And the transmitting device is a symbol

and

Symbol using

and

Convert to S430. symbol

Real part of the symbol

The symbol of the real part of

Real part of the symbol

Converted to an imaginary part of

Imaginary symbol of

The symbol of the real part of

Imaginary symbol of

Is converted to the imaginary part of.

및

과 [수학식 2]에서의

이다. 채널 상태 정보는

,

및

를 포함한다. 이때

는 4-QAM 또는 16-QAM 방식에서 한 개 또는 두 개의 비트 정보로 대신할 수 있다.The transmitter determines the preprocessing matrix using the channel state information from the receiver (S440). The preprocessing matrix is expressed in Equation 8

And

And in [Equation 2]

to be. Channel status information is

,

And

It includes. At this time

Can be replaced with one or two bit information in 4-QAM or 16-QAM.

을 이용하여 유클리드 최소거리(

)를 최대화시도록 연산을 수행한다(S450). 그리고 송신 장치는 선처리 행렬

을 이용하여 심벌 내의 실수부와 허수부가 직교성을 가지도록 연산을 수행한다(S460). 또한 송신 장치는 선처리 행렬

을 이용하여 심벌 간에 직교성을 가지도록 연산을 수행한다(S470).Next, the transmitter is a preprocessing matrix.

Using the Euclidean minimum distance (

Operation is performed to maximize) (S450). And the transmitting device is a preprocessing matrix

In operation S460, the real part and the imaginary part in the symbol are orthogonal. In addition, the transmitting device is a preprocessing matrix

Operation is performed so as to have orthogonality between symbols (S470).

Thereafter, the transmitting apparatus transmits the processed symbols finally through the transmission antennas 170 and 175 (S480). The receiving device then performs an appropriate operation such as decoding the received symbol and converting it into a bit stream. In addition, the receiving apparatus generates channel state information based on the channel matrix and transmits the channel state information to the transmitting apparatus.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a block diagram illustrating a transmission apparatus of an orthogonal spatial multiplexing system according to an embodiment of the present invention.

2 is a view for explaining a method of determining a parameter value according to an embodiment of the present invention.

3 is a graph for explaining the performance of the transmission apparatus of the orthogonal spatial multiplexing system according to an embodiment of the present invention.

4 is a flowchart illustrating a line processing method of an orthogonal spatial multiplexing system according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: bit converting unit, 120, 125: mapping unit,

130: symbol converter, 140: first preprocessor,

150: second preprocessor, 160: third preprocessor,

170, 175: transmitting antenna, 180: feedback processing unit

Claims (16)

A preprocessing device of an orthogonal space multiplexing system, A feedback processor for determining a first preprocessing matrix and a second preprocessing matrix by using channel state information from the receiving apparatus; A first preprocessing unit performing an operation to maximize a Euclidean minimum distance by using the first preprocessing matrix determined by the feedback processing unit, and A second preprocessor configured to perform an operation such that the real part and the imaginary part in the first symbol are orthogonal to each other by using the second preprocessing matrix determined by the feedback processor. Preprocessing device comprising a. In claim 1, The first preprocessing matrix is

And said

Is

And

Is

And said

Wow

Is determined from the channel state information. In claim 2, When the modulation scheme is 4-QAM (Quadrature Amplitude Modulation), the channel state information includes one bit information.

Wow

Pretreatment device determined by the value of. In claim 2, When the modulation scheme is 16-QAM, the channel state information includes two bits of information, and any one of four pairs of predetermined values according to the two bits of information is determined.

Wow

Pretreatment device determined by the value of. In claim 1, The second preprocessing matrix is

And said

silver

And

Is included in the channel state information. In claim 1, The feedback processor determines a third preprocessing matrix by using the channel state information. The apparatus may further include a third preprocessor configured to perform orthogonality between the first symbols using the third preprocessing matrix determined by the feedback processor. Pretreatment device. In claim 6, The third preprocessing matrix is

And said

Is a preprocessing device included in the channel state information. In claim 1, A mapping unit for converting the bit stream into a second symbol, and Further comprising a symbol conversion unit for converting the second symbol into the first symbol, The first symbol is

And

The second symbol includes

And

Including; The symbol converting unit is the symbol

The real part of the symbol

As the real part of the symbol

The real part of the symbol

Convert to the imaginary part of

The imaginary part of the symbol

As the real part of the symbol

The imaginary part of the symbol

To the imaginary part of Pretreatment device. As a preprocessing method of an orthogonal space multiplexing system, Determining a first preprocessing matrix and a second preprocessing matrix using the channel state information from the receiving device, Performing an operation to maximize a Euclidean minimum distance using the first preprocessing matrix determined in the determining step, and Performing an operation such that the real part and the imaginary part in the first symbol are orthogonal to each other by using the second preprocessing matrix determined in the determining step. Pretreatment method comprising a. The method of claim 9, The first preprocessing matrix is

And said

Is

And

Is

And said

Wow

Is determined from the channel state information. In claim 10, When the modulation scheme is 4-QAM (Quadrature Amplitude Modulation), the channel state information includes one bit information, and any one of two pairs of predetermined values is determined according to the one bit information.

Wow

The pretreatment method determined by the value of. In claim 10, When the modulation scheme is 16-QAM, the channel state information includes two bits of information, and any one of four pairs of predetermined values according to the two bits of information is determined.

Wow

The pretreatment method determined by the value of. The method of claim 9, The second preprocessing matrix is

And said

silver

And

Is a preprocessing method included in the channel state information. The method of claim 9, Determining a third preprocessing matrix using the channel state information, and Performing an operation to have orthogonality between the first symbols using the determined third preprocessing matrix; The line processing method further comprising. The method of claim 14, The third preprocessing matrix is

And said

Is a preprocessing method included in the channel state information. The method of claim 9, Converting the bit stream into a second symbol, and Converting the second symbol into the first symbol, The first symbol is

And

The second symbol includes

And

Including; The symbol

The real part of the symbol

As the real part of the symbol

The real part of the symbol

Is converted to the imaginary part of

The imaginary part of the symbol

As the real part of the symbol

The imaginary part of the symbol

Preprocessing method that is converted to the imaginary part of.

Images