KR100712069B1 - Method for Estimating Channel of Multi-Antenna System - Google Patents

Abstract

The present invention relates to a transmission channel estimation method of a multi-antenna system, and more particularly, to a pilot frequency design and a channel estimation method of a multi-antenna system under a dual selective fading channel environment.

The present invention constructs the best cyclic orthogonal pilot frequency sequence in terms of least squares by using a Discrete Fourier Transform matrix at the transmitting end, intermittently inserts it into the dispatch data, create a structure; The receiver uses the characteristics of the cyclic orthogonal sequence to estimate the least significant squared channel with the lowest mean complexity error (MMSE) with low implementation complexity, and rapidly implements the channel estimation using the decomposition of the received pilot frequency matrix, After the channel estimation and noise variance estimation are performed by the pilot frequency section more accurately by using the transform, the channel parameter of the data section is estimated again using interpolation of the discrete cosine transform domain.

According to the present invention, the performance of the receiver can be improved by effectively improving the precision of the channel estimation, and in particular, the performance of the receiver can be improved under high speed and shift movement conditions that cannot be guaranteed by the conventional channel estimation method.

Multiple Antenna System, Discrete Fourier Transform, Time Slot

Description

Transport Channel Estimation Method of Multi-antenna System {Method for Estimating Channel of Multi-Antenna System}

1 is an intermittent pilot frequency timeslot structure adopted in the present invention. Among them, a cyclic protection section G, a pilot frequency section P, and a data section D are provided. The quantity K of the sub timeslot is adaptively adjusted according to the moving speed of the terminal.

Figure 2 is a schematic diagram of an application method for constructing each antenna pilot frequency sequence in the basic sequence structure of the present invention.

3 is a schematic diagram of a fast implementation apparatus which is a kind of least-squares channel estimation in the present invention. It consists of an ordering mode for adjusting the signal order, a phase rotation mode for rotating the signal phase, an FFT group, and an IFFT group.

4 is a detailed apparatus block diagram of channel estimation, which is a kind of the present invention. It is a least-squares channel estimation module of the received signal for each pilot frequency interval, a DCT module that performs discrete cosine transformation for all time domain estimates, a DCT domain single point noise cancellation and noise variance estimation module, and an inverse discrete cosine transformation for the signal. Consists of IDCT module to proceed.

The present invention relates to a transmission channel estimation method of a multi-antenna system, and more particularly, to a pilot frequency design and a channel estimation method of a multi-antenna system under a dual selective fading channel environment.

In order to adapt to the demands of future developments, super third-generation mobile communication systems must support all-IP data transmission at data rates of tens of megabits per second or even hundreds of megabits per second; Support high terminal mobility with travel speeds of several hundred kilometers per hour; Support high transmission quality to support high transmission quality in which the error rate of data task is less than ^10-6 ; Provide high frequency spectrum utilization of at least a few bits per hertz; Provide high power efficiency with emission power lower than 10 dB; It should effectively support large dynamic range changes in terms of user data rate, user capacity, quality of service and speed of travel.

Adopting an air interface mechanism for multi-antenna transmission and multi-antenna reception to improve the frequency spectrum utilization of the system is an effective solution. However, even in a multi-antenna environment, the super 3rd generation mobile communication system still requires very high bandwidth to effectively support high-speed data transmission. Bandwidth transmission adds to the selective fading of channel frequencies, resulting in severe multipath interference. In addition, the Doppler shift phenomenon due to the fast movement of the terminal increases the time selective fading of the channel. Therefore, among the super 3rd generation mobile communication systems, the fading of the channel is bi-selective.

Receivers in a communication system are classified into two types: coherent receivers and non-coherent receivers. The synchronous receiver needs to know the shock response coefficient of the channel at the receiving end, and further needs to estimate the channel at the receiving end. In addition, the asynchronous receiver does not need to know the impact response coefficient of the channel at the receiving end, but the transmission signal should be orthogonal modulated, and a loss of 3-4 dB may occur in performance. The present invention mainly considered a synchronous reception method which occupies the leading position among the super 3rd generation mobile communication systems.

In order to implement synchronous reception, it is necessary to perform channel estimation at the receiving end. In order to accurately estimate channel parameters on time, actual communication systems typically employ channel estimation methods based on pilot frequency sequences. The basic concept is to intermittently insert a pilot frequency at an appropriate position of the transmitter, and the receiver recovers channel information of the pilot position using the pilot frequency and then uses some processing means (e.g., interpolation, filter, conversion, etc.). To obtain channel information of all time intervals. Three problems are mainly related to this: (1) Selection and insertion of transmitter pilot frequency; (2) a receiver pilot frequency position channel information acquisition method; (3) Recover channel information at all times through channel information acquired at the pilot frequency position.

Accordingly, the present inventors have completed the present invention as a result of diligent efforts to solve the above problems and implement a technical method having a low complexity.

After all, the main object of the present invention is to provide a channel estimation method of a kind of multi-antenna system. The method can effectively improve the precision of channel estimation and improve the performance of the receiver, and can improve the receiver performance under high speed and variable shift conditions, which the conventional channel estimation method cannot guarantee.

In order to achieve the above object, a transmission channel estimation method of a multiple antenna system according to a feature of the present invention,
A method of estimating a transmission channel at a receiving end of a multiple antenna system,
a) receiving a transmission signal having a dual-cyclic time slot structure transmitted from a transmitting end, wherein the dual-cyclic time slot includes a plurality of sub timeslots and one end portion, each of the plurality of sub time slots each having a guard interval; A pilot frequency interval and a data interval, the end including a guard interval and a pilot frequency interval; b) performing channel estimation on a pilot frequency interval included in each of the plurality of sub timeslots using the received transmission signal; And c) performing channel estimation on data intervals included in the plurality of sub-timeslots through interpolation of a discrete cosine transform zone on the result of the channel estimation performed in step b), wherein the pilot frequency The interval may be included in the timeslot according to the cyclic orthogonal pilot frequency sequence based on the number of transmit antennas and the number of multipaths of the channel.

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Hereinafter, the present invention will be described in detail.

In the multi-antenna system of the present invention, the channel estimation method uses the Discrete Fourier Transform (DFT) matrix to construct the best cyclic orthogonal pilot frequency sequence in terms of least squares (LS), and inserts it intermittently into the transmission data. Create a timeslot structure of the circulation; The receiver uses the characteristics of the cyclic orthogonal sequence to estimate the least significant squared channel with the lowest mean complexity error (MMSE) with low implementation complexity, and rapidly implements the channel estimation using the decomposition of the received pilot frequency matrix and discrete cosine The frequency pilot domain performs more accurate channel estimation and noise variance estimation using the transform (DCT), and then obtains an estimate of the channel parameter of the data interval using discrete cosine transform (DCT) interpolation.

The method includes several steps:

및 채널의 다중경로 개수

를 근거로, 길이가

인 최소자승 의미상 가장 바람직한 순환직교 파일럿 주파수 시퀀스 s 를 구축하고, 아울러 다음과 같은 규칙에 따라 각 송신안테나의 파일럿 주파수 시퀀스을 생성한다:Step 1) Number of transmitting antennas in the multiple antenna system at the transmitting end

The number of multipaths in the channel and channel

Based on the

Constructs the most desirable cyclic orthogonal pilot frequency sequence s by means of least squares, and generates a pilot frequency sequence for each transmit antenna according to the following rules:

;

;

Step 2) At the receiving end, the estimated value of the channel shock response coefficient of each pilot frequency interval in one time slot is obtained according to the following formula.

;

;

Step 3) At the receiving end, the channel shock response estimated using step 2) estimates the primary channel noise variance for each pilot frequency interval according to the following formula and obtains the noise variance estimate of the previous timeslot:

;

;

Step 4) At the receiving end, the channel shock response of all the pilot frequency sections estimated using step 2) is subjected to noise removal processing and noise variance estimation in a point-to-point manner in the DCT zone, and the discrete cosine transform DCT zone. Through the interpolation of, the channel shock response of the data section is obtained.

In the above method, the cyclic orthogonal pilot frequency sequence s is constructed of a Fourier transform matrix and satisfies the cyclic orthogonal characteristic. The pilot frequency sequence of each transmit antenna is obtained by the position shift of the s cycle. The least square refers to estimating the square of the error and the minimum. The estimating step 2 of the channel shock response coefficient proceeds with respect to the sub timeslot, and there is a fast implementation calculation method for estimating the channel shock response coefficient using the following decomposition of the received pilot frequency matrix.

The estimation step 4 of the channel shock response coefficient is performed in one time slot. The noise cancellation and interpolation of the channel shock response coefficients are all performed in the discrete cosine transform DCT domain.

DETAILED DESCRIPTION In order to more clearly understand the objects, technical methods and advantages of the present invention, the implementation of the technical methods will be described in detail with reference to the accompanying drawings.

At the transmitting end, using the Discrete Fourier Transform (DFT) matrix, constructing the best cyclic orthogonal pilot frequency sequence in the least squares (LS) meaning, and inserting it intermittently into the transmission data to build a double-cyclic time slot structure; The receiver uses the characteristics of the cyclic orthogonal sequence to perform the best least-squares channel estimation in terms of minimum mean square error (MMSE) with low implementation complexity, and rapidly implements channel estimation by using decomposition of the received pilot frequency matrix. Using the Cosine transform (DCT), the pilot frequency section performs more accurate channel estimation and noise variance estimation, and then uses the discrete cosine transform (DCT) interpolation to estimate the channel parameters of the data domain.

The method includes several steps as follows.

및 채널의 다중경로 개수

를 근거로, 길이가

인 최소자승의미상 가장 우수한 순환직교 파일럿 주파수 시퀀스 s 를 구축하고, 아울러 다음과 같은 규칙에 따라 각 송신안테나의 파일럿 주파수 시퀀스를 생성한다:Step 1) Number of transmitting antennas in the multiple antenna system at the transmitting end

The number of multipaths in the channel and channel

Based on the

We construct the best cyclic orthogonal pilot frequency sequence, s , and generate the pilot frequency sequence for each transmit antenna according to the following rules:

;

;

Step 2) At the receiving end, the estimated value of the channel shock response coefficient of each pilot frequency interval in one timeslot is obtained according to the following formula.

;

;

Step 3) At the receiving end, the channel shock response estimated using step 2) estimates the primary channel noise variance for each pilot frequency interval according to the following formula and obtains the noise variance estimate of the previous timeslot:

;

;

Step 4) At the receiving end, the channel shock response of all the pilot frequency sections estimated using step 2) is performed by the noise elimination process and the noise variance estimation in a point-to-point manner in the DCT region, and the discrete cosine transform DCT domain. Through the interpolation of, the channel shock response of the data section is obtained.

In the above method, the cyclic orthogonal pilot frequency sequence s is constructed with a Fourier transform matrix and satisfies the cyclic orthogonal characteristic. The pilot frequency sequence of each transmit antenna is obtained by s-cycle position shift. The least square refers to estimating the square of the error and the minimum. The estimating step 2 of the channel shock response coefficient proceeds with respect to the sub-time slots. There is a fast implementation algorithm for estimating the channel shock response coefficient using the following decomposition of the received pilot frequency matrix. The estimation step 4 of the channel shock response coefficient is performed in one time slot. Noise rejection and interpolation of the channel shock response coefficients are all performed in the discrete cosine transform DCT domain.

1. System Model

이다. 서브 타임슬롯 개수 K는 터미널의 이동속도를 근거로 설정한다.1 shows an intermittent pilot frequency timeslot structure of an outgoing signal. Set K subtimeslots in each timeslot, and the number of pilot frequency intervals

to be. The number of sub timeslots K is set based on the moving speed of the terminal.

로, 수신 안테나의 개수를

로, 채널충격응답시퀀스의 길이를

로 설정하면, 각 수신 통로에서 추정하고자 하는 채널 파라미터 개수는

이다. 이와 상응하여, 파일럿 주파수 시퀀스의 길이는

이다(그 중

는

보다 작지 않은 최소정수를 나타낸다).In a MIMO system, the number of transmit antennas

The number of receive antennas

The length of the channel shock response sequence

If set to, the number of channel parameters to be estimated in each reception path is

to be. Correspondingly, the length of the pilot frequency sequence is

(Of which

Is

Least integer not less than).

를 이용하여 n번째 근의 수신 안테나의 파일럿 주파수 시퀀스를 표시하면,

는 모든 안테나의 발송 파일럿 주파수 신호를 나타낸다. 수신단에서 순환보호 후의 K 개째의 파일럿 주파수 구간의 수신신호는 다음과 같이 표시할 수 있다.

If denotes the pilot frequency sequence of the n-th reception antenna using

Denotes the outgoing pilot frequency signal of all antennas. The received signal of the K-th pilot frequency interval after the cyclic protection at the receiving end can be expressed as follows.

[공식 1]

[Formula 1]

와

는

의 매트릭스로서, 전송받은 파일럿 주파수 신호 및 분산이

인 부가화이트가우시안노이즈(Additive white gaussian noise)를 나타낸다.

는

의 매트릭스로서,

는 k 개째의 파일럿 주파수 구간, m 번째 근의 수신안테나와 n 번째 근의 송신안테나 사이의 P번째 경로인 채널 탭(tap) 계수를 나타낸다.

는 S의 행렬순환을 우측의 P 위치로 이동시켜 얻은 것이다.among them

Wow

Is

As a matrix of, the received pilot frequency signal and its variance

Phosphorus represents additive white gaussian noise.

Is

As a matrix of

Denotes a channel tap coefficient, which is the P-th path between the k-th pilot frequency interval, the m-th reception antenna and the n-th transmission antenna.

Is obtained by shifting the matrix cycle of S to the right P position.

이 k 개째 파일럿 주파수 구간의 모든 채널 파라미터에 표시되도록 하면,

이며, 공식 1은 다음과 같이 바꿔 쓸 수 있다.

If we want to display all the channel parameters of this kth pilot frequency interval,

Equation 1 can be rewritten as

[공식 2]

[Formula 2]

The least squares (LS) estimate of the channel parameters obtained with the linear pattern depicted in Equation 2 is:

[공식 3]

[Formula 3]

일 때, 노이즈 분산의 비편향 추정량은 다음과 같다.

When the non-biased estimator of the noise variance is as follows.

[공식 4]

[Formula 4]

은 매트릭스의 F 놈(norm)을 나타낸다. 이론 분석은

일 때, 위의 LS 추정이 가장 바람직한 성능을 가지며, 또한 매트릭스가 역연산을 구하는 것을 생략할 수 있다는 것을 나타낸다.among them

Denotes the F norm of the matrix. Theoretical analysis

When the LS estimation above has the most desirable performance, it also indicates that the matrix can omit finding the inverse operation.

2. Most Preferred Pilot Frequency Sequence Structure

는 길이가

인 순환직교시퀀스로서, 우리는 이를 기본 시퀀스로 하여 다음과 같은 규칙에 따라 각 안테나의 파일럿 주파수 시퀀스를 구축 한다.

Has a length

As an cyclic orthogonal sequence, we use this as the base sequence and construct a pilot frequency sequence for each antenna according to the following rules.

[공식 5]

[Formula 5]

은 n 대N 의 모듈연산을 나타낸다. s가 순환직교시퀀스일 때, 공식 5에 따라 구축한 파일럿 주파수 시퀀스는 앞의 직교 조건을 만족시킨다는 것을 검증할 수 있다.among them

Denotes a modular operation of n to N. When s is a cyclic orthogonal sequence, it can be verified that the pilot frequency sequence constructed according to Equation 5 satisfies the preceding orthogonal condition.

와

의 순환직교 시퀀스를

점 DFT 매트릭스 원소로부터 직접 얻을 수 있다. W를 N점 DFT 매트릭스로 설정하면 그 원소는

이며, 아울러

로 설정하면, 그 중

와

은 모두

의 서브 매트릭스이다. 만약

이고,

이 되도록 하면, 즉

는 길이가

인 순환직교시퀀스 벡터이다. 여기서

는 확장연산자이다.Regarding the structure of the cyclic orthogonal sequence, it has already been reported in the literature, and we

Wow

Circular orthogonal sequence of

Can be obtained directly from the point DFT matrix elements. If we set W to an N point DFT matrix, the element

And

If set to,

Wow

Is all

Is a submatrix of. if

ego,

, That is,

Has a length

Is a cyclic orthogonal sequence vector. here

Is an extension operator.

3. Implementation of Least Squares Channel Estimation

가 직교조건

을 만족시킬 때, 공식 3은 다음과 같이 단축할 수 있다.matrix

Orthogonal Condition

To satisfy, Eq 3 can be shortened as

[공식 6]

[Formula 6]

를 수신한 후 직접 공식 6을 이용하여 채널 추정을 하면 공식 3의 계산과 비교할 때 복잡한 매트릭스 역연산을 생략할 수 있다. 더 나아가 매트릭스

의 구조를 연구하면 다음과 같은 두 가지 분해 형식이 있음을 발견할 수 있다:The receiving end

After receiving, direct channel estimation using Equation 6 can be used to omit complex matrix inverse operations when compared with Equation 3. Further the matrix

By studying the structure of, we find that there are two forms of decomposition:

[공식 7]

[Formula 7]

[공식 8]

[Formula 8]

는

점의 DFT 매트릭스이고,

이며,

는

를 치환하여 생성된

레벨 치환 매트릭스이다. 공식 8 중,

는

레벨의 대각 매트릭스(diagonal matrix)이고,

는 각각

를 치환하여 생성된

레벨 치환 매트릭스이며,

이다. 그 중

는 주 대각원이

인 대각 매트릭스이고,

는 매트릭스의 Kronecker 곱을 나타낸다. 상기 각 치환의 생성 규칙은 다음과 같다:In the formula 7,

Is

Is the DFT matrix of points,

Is,

Is

Generated by substituting

Level substitution matrix. In the formula 8,

Is

The diagonal matrix of levels,

Are each

Generated by substituting

Level substitution matrix,

to be. among them

Is the main diagonal

Is a diagonal matrix,

Denotes the Kronecker product of the matrix. The rules for generating each substitution are as follows:

는 공식 8로부터 그 대각 원소를 역추산할 수 있다. 공식 6, 7, 8로부터 우리는 시작 LS 채널 추정의 세 가지 알고리즘을 얻을 수 있다.Diagonal matrix

Can infer the diagonal element from Equation 8. From Equations 6, 7, 8 we can get three algorithms of starting LS channel estimation.

이다;(1) direct calculation (Formula 6), the number of plural multiplication operations

to be;

이다;(2) Quick calculation method 1 (formula 7), the multiplication method

to be;

이다.(3) Quick calculation method 2 (formula 8), the multiplication method

to be.

2 is an apparatus diagram for implementing LS channel estimation by Equation 8.

4. More accurate channel estimation

일 때, 공식 4로 노이즈 분산 추정을 할 수 없는데, 이때는 채널 매개변수의 시간 상관성을 이용하여 노이즈 분산 추정을 진행할 수 있다.In the above, the least-squares channel estimation and the noise variance estimation method based on a single pilot frequency interval are presented. In the dual-cyclic adaptive timeslot structure, there are a number of pilot frequency intervals, and more accurate channel estimation can be performed by using time correlation that estimates channel parameters. Besides

In this case, the noise variance estimation cannot be performed using Equation 4. In this case, the noise variance estimation can be performed using the time correlation of the channel parameter.

으로 적어,

번째 전송통로의 p 개째 경로에서 얻은

개의 채널 매개변수를 나타내면 즉

번째 전송통 로에서 획득한 모든 채널의 매개변수는 다음과 같이 쓸 수 있다:

Write it down,

From the pth path of the first transmission path

Representing two channel parameters,

The parameters of all channels acquired in the first transmission channel can be written as follows:

That is,

[공식 9]

[Formula 9]

은

과 상응하는 이상적인 채널 벡터이며,

은 0 평균치 화이트 가우시안 노이즈 벡터로, 그 각 원소의 분산은

이다.among them

silver

Is the ideal channel vector corresponding to

Is a zero mean white Gaussian noise vector whose variance is

to be.

의 최소평균분산오차(MMSE)는 다음과 같이 추정한다:As Equation 9 shows,

The minimum mean variance error of MMSE is estimated as:

[공식 10]

[Formula 10]

이다. 여기서 우리는 각 전송통로 중 서로 동일한 공률 지연 스펙트럼(PDP)을 갖추고 있다고 가정하고, 더 나아가 채널 통계 특성이 타임 도메인 또는 주파수 도메인으로 분리되는 성질을 이용하여, 앞의 상관 매트릭스

을

로 분해할 수 있다. 그 중

이며,

는 채널의 p 번째 경로의 공률이다.

은 도플러 주파수변환으로 확정된 채널 타임도메인 통계특성이다.

의 분해를 이용하여 공식 10은 차원축소(dimensionality reduction)로 구현할 수 있다. 즉:among them

to be. Here we assume that each transmission path has the same power delay spectrum (PDP), and furthermore, by using the property that channel statistics are separated into time domain or frequency domain,

of

Can be decomposed into among them

Is,

Is the power of the p th path of the channel.

Is the channel time domain statistics determined by Doppler frequency conversion.

Using the decomposition of, Equation 10 can be implemented as dimensionality reduction. In other words:

[공식 11]

[Formula 11]

이다.among them

to be.

는 Hermite 매트릭스이기 때문에 특징을

로 분해할 수 있으며, 그 중

는 직교 매트릭스이고

이다. 상기 특징을 이용하여 분해하면 공식 11은 다음과 같이 바꿔 쓸 수 있다.

Is characterized by the Hermite matrix

Can be broken down into

Is an orthogonal matrix

to be. Decomposed using the above feature, Equation 11 can be rewritten as

[공식 12]

[Formula 12]

이다.among them

to be.

의 MMSE 추정을 구현하기 위하여, 상관 매트릭스

를 실측할 필요가 있으며, 또한 이에 대하여 특징 분해를 진행한다. 각기 다른 전송 통로는 동일한

를 지닌다는 점을 고려하여, 공간상의 샘플을 직접 이용하여

에 대해 추정을 진행하면 즉 다음과 같다.

In order to implement the MMSE estimation of the correlation matrix

Needs to be measured and feature decomposition proceeds. Different transport passages are identical

Taking into account the fact that

If we proceed with the estimation for,

점의 DCT 매트릭스를 이용하여 앞의 직교매트릭스

를 대체하고, 아울러 DCT 변환 도메인에서 point by point 방식으로 노이즈 제거 처리와 노이즈 분산 추정을 진행한 후, 역 DCT 변환을 통하여

MMSE 추정의 근사해(approximate solution)를 얻을 수 있다. 이론 분석과 시뮬레이션 결과 모두 상기 방법이 효과적이라는 것을 입증하였다.On the basis of studying time domain correlation matrix properties to avoid complex matrix feature decomposition operations, we approach the feature decomposition of the correlation matrix using discrete cosine transform (DCT), that is,

The previous orthogonal matrix using the DCT matrix of points

In addition, the noise reduction process and noise variance estimation are performed by the point by point method in the DCT transform domain.

An approximate solution of the MMSE estimate can be obtained. Both theoretical analysis and simulation results have demonstrated that the method is effective.

5. Channel estimation of the data interval

After the channel parameters of the pilot frequency intervals are obtained, the channel parameters of the data intervals should be traced or estimated. Commonly used methods include linear interpolation, Gaussian linear interpolation, and weighted multi-timeslot average (WMSA), all of which are simple linear processing methods, and their common drawbacks are the speed of mobile stations. Is too fast, the channel attenuation transition is either very fast or a nonlinear change appears so that a data channel linearly processed using the pilot frequency channel cannot truly reflect the channel change situation.

점의 DCT를 이용하여

를 DCT 도메인으로 변환하여 하나의

차원의 벡터를 얻고, 그 말미에

개의 0 원소를 추가하여

차원의 벡터를 얻는다. 그 중

은 데이터 구간의 인터폴레이션 팩터(factor)이며, 다시 말해 각 샘플값 후면에서

개의 값을 삽출하고, 마지막으로 다시

점의 역DCT 변환을 이용하여 이를 타임 도메인으로 변환하여 되돌린다. DCT 인터폴레이션의 끝머리 효과(edge effect)에 의해 말미부의

개의 데이터가 그다지 정확하지 않으므로, 뒤에 이어지는 검측 중 이러한 데이터가 결코 필요하지 않다는 점을 고려하여 말미부의

개의 데이터를 삭제하였다. 인터폴레이션 후 얻은 채널 매개변수의 길이는

이다. 공식 12와 결합하여, 상기 처리과정을 공식으로 표현하면 다음과 같다.Here we interpolate the channel parameters in the DCT domain. The specific process is as follows:

Using DCT of points

To a DCT domain

Get a vector of dimensions,

By adding 0 elements

Get a vector of dimensions. among them

Is the interpolation factor of the data interval, i.e. at the back of each sample value

Values, and finally

The inverse DCT transformation of the point is used to convert it back to the time domain. The edge effect of DCT interpolation

Data is not very accurate, so the following detection does not require this data at the end.

Data was deleted. The length of the channel parameter obtained after interpolation

to be. In combination with Equation 12, the above process is expressed as a formula.

[공식 13]

[Formula 13]

은

점의 확장 가능한 DCT 매트릭스이고,

은 인터폴레이션 후의 출력 채널 매개변수이다.

일 때, 공식 13의 실수승법 횟수는 224이다.among them

silver

Is an expandable DCT matrix of points,

Is the output channel parameter after interpolation.

, The number of real powers of Equation 13 is 224.

As described in detail above, the present invention has an effect of providing a method for constructing a pilot frequency sequence and a channel estimating method used for channel estimation of a kind of a multi-antenna transmission system. The pilot frequency sequence generated according to the method of the present invention can implement the best channel estimation in terms of least squares with a relatively low computational complexity, and at the same time, a low complexity through a process for transforming a domain using characteristics related to the time domain of the channel. In terms of MMSE, the best approximate solution can be obtained, and the accuracy of channel estimation can be improved.

Comparing the channel estimation method provided by the present invention with the prior art, the accuracy of channel estimation can be effectively improved, and in particular, the performance of a receiver can be improved in high speed and shift movement situations, which the conventional channel estimation method is difficult to guarantee. have. This channel estimation method does not need a long pilot frequency sequence, but also has a very small amount of computation and storage, making it easy to implement in hardware.

Claims (9)

In the method of estimating the transmission channel at the receiving end of the multi-antenna system, a) receiving a transmission signal having a dual-cyclic time slot structure transmitted from a transmitting end, wherein the dual-cyclic time slot includes a plurality of sub timeslots and one end portion, each of the plurality of sub time slots each having a guard interval; A pilot frequency interval and a data interval, the end including a guard interval and a pilot frequency interval; b) performing channel estimation on a pilot frequency interval included in each of the plurality of sub timeslots using the received transmission signal; And c) performing channel estimation on the data intervals included in the plurality of sub-timeslots through interpolation of the discrete cosine transform zone with respect to the result of the channel estimation performed in step b). Including; The pilot frequency interval is included in the timeslot according to a cyclic orthogonal pilot frequency sequence based on the number of transmit antennas and the number of multipaths of a channel. Transmission Channel Estimation Method of Multiple Antenna System. The method of claim 1, The cyclic orthogonal pilot frequency sequence is the number of transmit antennas (

) And the number of multipaths for that channel (

On the basis of

(here,

Is

Is not less than the smallest integer), and

here,

Is a modular operation of n versus N The transmission channel estimation method of the multi-antenna system is generated by a pilot frequency sequence included in the transmission signal corresponding to each transmission antenna according to. The method according to claim 1 or 2, The cyclic orthogonal pilot frequency sequence s is constructed of a Fourier transform matrix to satisfy cyclic orthogonal characteristics; And a pilot frequency sequence of each transmit antenna is obtained by s cyclic shift. delete The method of claim 2, According to the channel estimation performed in step b), the estimated value of the channel shock response coefficient in the pilot frequency section is represented by the following relational expression.

here,

Is the received pilot frequency signal,

Is,

Denotes signals of pilot frequency intervals of all transmitting antennas.

The value obtained by moving the matrix cycle of to P position. Transmission channel estimation method of a multi-antenna system calculated by. The method of claim 5, In step (b), the estimation of the channel shock response coefficient is performed in one time slot; Noise cancellation and interpolation of channel impact response coefficients are all performed in a discrete Fourier transform "DFT" domain. The method of claim 5, The estimated value of the channel shock response coefficient is

here,

Is

Discrete Fourier transform matrix of points,

Is,

Is the main diagonal

Is a diagonal matrix

Is

Generated by substituting

Is a level substitution matrix Transmission channel estimation method of a multi-antenna system calculated by. The method of claim 5, The estimated value of the channel shock response coefficient is

here,

Is

The diagonal matrix of levels,

Are each

Generated by substituting

Level substitution matrix,

ego,

Multiplied by Kronecker in Matrix Transmission channel estimation method of a multi-antenna system calculated by. The method of claim 7, wherein The channel estimation performed in step c) is as follows.

here,

silver

A scalable discrete cosine transform matrix of points,             K is the number of sub timeslots included in the timeslot,             L is an interpolation factor of the data interval,

to,

From the pth path of the first transmission path

Channel parameters

Is an orthogonal matrix A method of estimating a transmission channel of a multi-antenna system is performed by to calculate an estimated value of the channel shock response of the data interval.

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