KR100905549B1 - Method and Apparatus for Selection of Transmitting Antennas In Uplink of MIMO Wireless Communication System - Google Patents

Abstract

The present invention relates to a method and apparatus for selecting a transmission antenna of a multi-input multiple output wireless communication system, and more particularly, to a method and apparatus for selecting a transmission antenna capable of maximizing a system capacity in an uplink of a multi-input multi-output wireless communication system. will be.

A method of selecting a transmit antenna in a multiple input multiple output wireless communication system according to the present invention comprises the steps of: receiving information on a received channel correlation of a base station from a multiple transmit antenna; Calculating a system measurement capacity for transmission antenna selection using information on a reception signal-to-noise ratio (SNR) of each reception channel of the multiple transmission antenna and the reception channel correlation; Selecting a combination of transmit antennas at which the calculated system measurement capacity is maximized; Scheduling multiple users and the multiple transmit antennas according to the selected transmit antenna combination; And transmitting the scheduling information in the scheduling step to the multiple transmit antenna.

MIMO, uplink, transmit antenna selection, receive channel correlation

Description

TECHNICAL FIELD & Apparatus for Selection of Transmitting Antennas In Uplink of MIMO Wireless Communication System}

1 is a diagram schematically illustrating a multiple input multiple output system in uplink of a wireless communication system according to an exemplary embodiment of the present invention.

2 is a diagram conceptually illustrating a method for selecting a transmit antenna in uplink according to an embodiment of the present invention.

3 is a diagram illustrating an example of user scheduling according to the method of selecting a transmission antenna shown in FIG. 2.

4 is a diagram schematically illustrating a part of a configuration of a base station including an apparatus for selecting a transmit antenna in uplink according to an embodiment of the present invention.

5 is a flowchart illustrating a method of selecting a transmit antenna in uplink according to an embodiment of the present invention.

6 is a diagram illustrating an example of a transmission antenna selection method according to a preferred embodiment of the present invention used in combination with a conventional antenna selection method.

7 is a diagram illustrating a method of variably adjusting the number of transmit antennas according to an embodiment of the present invention.

8 is a diagram illustrating an example of a method of selecting a transmit antenna according to an embodiment of the present invention used in combination with the operation of a virtual transmit antenna.

9 is a diagram illustrating an example of applying a transmission antenna selection method according to an embodiment of the present invention when the base station supports multiple sectors.

10 is a view for explaining the effect of increasing the system measurement capacity in accordance with the transmission antenna selection method according to an embodiment of the present invention.

The present invention relates to a method and apparatus for selecting a transmission antenna of a multi-input multiple output wireless communication system, and more particularly, to a method and apparatus for selecting a transmission antenna capable of maximizing a system capacity in an uplink of a multi-input multi-output wireless communication system. will be.

In the uplink of the wireless communication system, it is very important to maximize the system capacity because the frequency band is limited. In general, it is known that the system capacity can be increased by increasing the spatial resources by using the multiple input and multiple output (hereinafter referred to as 'MIMO') to increase the system capacity with limited frequency resources. By Winters, "On the capacity of radio communications systems with diversity in a Rayleigh fading environment," IEEE J. Select.Areas Commun., Vol. 5, no. 5, pp. 871-878, June 1987; GJ "Layered space-time architecture for wireless communication in fading environments when using multi-element antennas," Bell Labs Tech. J., vol. 1, no. 2, pp. 41-59, autumn 1996; E. "Capacity of multi-antenna Gaussian channels," Eur. Trans. Telecomm., Vol. 10, no. 6, pp. 585-596, November 1999). In particular, in the uplink of a wireless communication system using MIMO, all users transmit simultaneously to all antennas, and a minimum mean square error (hereinafter referred to as 'MMSE') and continuous interference cancellation at a base station; It is theoretically known that receiving a combination of methods can maximize system capacity (also referred to as 'SIC') (A. Goldsmith, SA Jafar, N. Jindal and S. Vishwanath, “Capacity limits of MIMO channels,” IEEE J. Select.Areas Commun., Vol. 21, no. 5, pp. 684-702, June 2003), which requires the base station to know channel information from the transmit antennas of all users.

In order to estimate the channel information, a transmission pilot is generally used, resulting in a very large signaling overhead, and a combination of MMSE and SIC methods for signals received from all transmission antennas of all users. As a result, computational complexity is so severe that it is difficult to apply in practice (D. Tse and P. Viswanath, Fundamentals of wireless communication, Cambridge University Press, first edition, 2005). In addition, even when receiving a combination of these methods, when a signal of more than the number of receiving antennas, that is, the spatial degrees of freedom, is received, interference caused by them cannot be completely eliminated (D. Tse and P. Viswanath, Fundamentals of wireless communication, Cambridge University Press, first edition, 2005), has practically been considered a way of limiting the number of antennas that transmit simultaneously in one scheduling time to the number of receiving antennas or less. (IEEE P802.16e, "Draft IEEE standard for local and metropolitan area networks, z'Std., September 2004; 3GPP," Physical layer aspects for evolved universal terrestrial radio access (UTRA), "TR 25.814 V7.0.0 , June 2006; IEEE 802.20 WG, "QFDD and QTDD: Proposed draft air interface specification," October 2005).

Therefore, it is necessary for the base station to select a user so that the system capacity can be increased in consideration of these matters. If the base station completely knows the instantaneous channel information of the user transmit antenna, it selects the transmitting antenna to increase the channel capacity using the base station. (X. Shao and J. Yuan, "Multiuser scheduling for MIMO broadcast and multiple access channels with linear precoders and receivers," IEEE Proc. Commun., Vol. 153, no. 4, pp. 541-547 , August 2006). However, this requires an additional signal for channel estimation, such as channel sounding, to measure the instantaneous channel of the user transmit antenna (TA Thomas, KL Baum and P. Sartori, “Obtaining channel knowledge for closed -loop multistream broadband MIMO-OFDM communications using direct channel feedback, "Proc. IEEE Global Communications Conf., pp. 3907-3911, November 2005). In particular, when the user's moving speed is high, channel characteristics may be different (channel mismatch) when the base station selects a transmitting antenna and when the transmitting antenna actually transmits a signal (Q. Ma). And C. Tepedelenlioglu, "Practical multiuser diversity with outdated channel feedback," IEEE Trans.Veh. Technol., Vol. 54, no. 4, pp. 1334-1345, July 2005).

For this reason, in the related art, a round robin selection method in which a base station selects transmit antennas in order without information on a channel of a user transmit antenna is considered, but performance in an environment in which a reception channel correlation of a base station exists There was a problem of severe deterioration (JP Kermoal, L. Schumacher, KI Pedersen, PE Mogensen and F. Frederiksen, "A stochastic MIMO radio channel model with experimental validation," IEEE J. Select. Areas Commun., Vol. 20, no. 6, pp. 1211-1226, August 2002).

Summarizing the problems of the prior art as described above are as follows. In the uplink of the MIMO system, it is theoretically possible to maximize system capacity by allowing all users to transmit simultaneously to all transmit antennas without any selection at the base station, and then receiving the minimum mean square error and continuous interference cancellation at the base station. However, the burden of the pilot signal for channel estimation and the number of multiple reception signals larger than the number of base station reception antennas, it is difficult to apply in the current performance due to the interference caused from these. Therefore, in a practical environment, the number of transmitting antennas transmitting signals simultaneously is limited to less than or equal to the available degrees of freedom of the system (ie, the number of receiving antennas at the base station). Therefore, it is effective to select a transmit antenna in a base station using instantaneous channel information of multiple transmit antennas, but it is difficult to expect an improved performance due to a channel prediction burden and a problem of channel characteristic mismatch in a fast user speed environment. In addition, the user selection of the cyclic order method that does not use the channel information in the base station is severely degraded in an environment where the reception channel correlation exists, and thus high system capacity cannot be obtained.

In order to solve the above-mentioned problems of the prior art, it is desirable to select a transmission antenna using a method of additional low cost. For example, it is known that channel correlation information of a receiving channel can be obtained from a base station with a small burden, but the characteristic changes relatively slowly even in a fast user environment (M. Nicoli, O. Simeone and U). Spagnolini, "Multislot estimation of fast-varying space-time communication channels," IEEE Trans.Signal Processing, vol. 51, no. 5, pp. 1184-1195, May 2003), the present invention relates to such a receiving channel. A multi-antenna selection method for increasing system capacity of an uplink using reception channel correlation information of a transmitting antenna in an uplink of a MIMO wireless communication system having a correlation.

That is, the present invention relates to a multi-antenna selection method capable of increasing system capacity by using reception channel correlation information of a transmission antenna that can be obtained with a low complexity, and a basic concept is as follows. In general, since the channel correlation of the base station reception signal in the uplink of the MIMO system is different for each user transmission antenna, especially when the reception channel correlation is large, the reception channel correlation is selected to transmit transmission antennas having orthogonal characteristics to each other. By doing so, it is possible to increase the system capacity of the uplink.

According to an aspect of the present invention, there is provided a method of selecting a transmit antenna in an uplink of a multiple input multiple output wireless communication system according to the present invention, the method comprising: receiving information on a reception channel correlation of a base station from a multiple transmit antenna; Calculating a system measurement capacity for transmission antenna selection using information on a reception signal-to-noise ratio (SNR) of each reception channel of the multiple transmission antenna and the reception channel correlation; Selecting a combination of transmit antennas at which the calculated system measurement capacity is maximized; Scheduling multiple users and the multiple transmit antennas according to the selected transmit antenna combination; And transmitting the scheduling information in the scheduling step to the multiple transmit antenna.

Here, the information on the reception signal-to-noise ratio and the reception channel correlation of each reception channel of the multiplex transmission antenna may be estimated using an uplink channel prediction signal or estimated using a downlink pilot signal.

In addition, the system measurement capacity calculation step is preferably calculated by the following equation.

는 시스템 채널 행렬이고,

은 m 번째 송신 안테나의 수신 채널 상관도를 나타내는 행렬이고,

은 m 번째 송신안테나의 수신신호대잡음비이고,

는 행렬

의 대각합(trace)을 나타낸다고 할 경우,

은, 총 M 개 중 한 개씩 따로 선택하여

을 생성하거나, L(≥2)개의 서로 다른 송신 안테나의 수신 채널 상관도 행렬들을 묶어서 선택하여 생성한

의 수가 모두 i 개인 집합을 원소로 가지는 집합을 나타내고,

는 집합

의 j 번째 원소 집합이며, 선택한

과

로 이루어진 집합의 tr(·) 안에 곱해져 있는 서로 다른 송신 안테나의 수신 채널 상관도 행렬들의 수가 동일한 형태인 집합을 원소로 가지는 집합이며,

는 집합

의 k 번째 원소 집합으로

또는

의 형태로 표현되는

을 l 번째 원소로 가지며,

는

의 tr(·) 안에 곱해져 있는 서로 다른 송신 안테나의 수신 채널 상관도 행렬들의 수를 나타내고,

는 집합

의 원소의 수를 나타낸다. here,

Is the system channel matrix,

Is a matrix representing the received channel correlation of the m th transmit antenna,

Is the received signal-to-noise ratio of the mth transmit antenna,

Is a matrix

Suppose we have a trace of,

Select one of the total M

Generated by combining the received channel correlation matrices of L (≥2) different transmit antennas

Represents a set whose elements are the set of all i s,

Set

Is the set of j th elements of

and

Receive channel correlation of different transmit antennas multiplied in tr (·) of a set consisting of

Set

As the set of k th elements of

or

Represented in the form of

Has as the l th element,

Is

Denotes the number of receive channel correlation matrices of different transmit antennas multiplied in tr (·) of

Set

It represents the number of elements of.

In addition, it is preferable that the transmission antenna combination having the maximum system measurement capacity for the transmission antenna selection is a combination of transmission antennas whose reception channel correlations are orthogonal to each other.

In addition, in the scheduling step, it is preferable to determine a scheduling method of maximizing the system measurement capacity using a scheduling method such as the following equation.

은 송신 안테나의 총 개수이고, M은 선택된 송신 안테나의 개수이고,

는, 다음 수학식과 같은 개수의

개의 송신 안테나를 M개씩 선택하여

번의 스케줄링 동안 스케줄링하는 방법 중

번째 방법에서 t번째 스케줄링 시간에 얻을 수 있는 시스템 측정 용량을 나타낸다.here,

Is the total number of transmit antennas, M is the number of selected transmit antennas,

Is the same number as

Select M transmit antennas

Of scheduling during one scheduling

In the second method, the system measured capacity obtained at the t-th scheduling time is shown.

.

.

The method further includes, after receiving the information about the received channel correlation, the spectral norm and the eigen-spread of the received channel correlation using the information about the received channel correlation. calculating a value spread); And

The method may further include comparing the calculated eigenvalue spread value of the received channel correlation with a threshold value, and calculating the system measurement capacity only when the eigenvalue spread value is greater than or equal to the threshold value.

In addition, the method may divide the multiple transmit antennas into a predetermined number of groups, and select a combination of transmit antennas for each group.

The calculating of the system capacity may include calculating a system measurement capacity according to the number of transmission antennas of the selected transmission antenna combination and a selection method, and the method may include calculating and selecting the number of transmission antennas calculated in the system capacity calculation step. Adding a system measurement capacity reduction due to a system burden according to the number of transmission antennas selected from the system measurement capacity according to the method; And determining a selection method of maximizing a system measurement capacity reflecting a reduction in measurement capacity according to the number of transmission antennas selected.

에

인 송신 가중치 벡터

를 곱함으로써

인 가상적인 송신 신호 벡터

를 이용하여 생성될 수 있고, 상기

는, 상기 u번째 사용자가 가진 송신 안테나의 수신 채널 상관도를 고려하여 시스템 용량이 증가될 수 있도록 설계하여 상기 기지국에서 하향링크 채널을 통해 전달하는 것이 바람직하다. In addition, the multiple transmit antennas may include a virtual transmit antenna, the virtual transmit antenna, the physical transmission signal of the u th user when the number of transmit antennas of the u th user of the total U users is P _u vector

on

Send weight vector

By multiplying

Virtual transmission signal vector

Can be generated using the above

It is preferable to design the system capacity to be increased in consideration of the reception channel correlation of the transmission antenna of the u-th user and to transmit it through the downlink channel in the base station.

In addition, the method may include both transmit antennas in cells and sectors supported by the base station when the base station supports multiple cells and multiple sectors.

Meanwhile, in order to achieve the above technical problem, an apparatus for selecting a transmission antenna in an uplink of a multiple input multiple output wireless communication system according to the present invention receives and receives information regarding a reception channel correlation of a base station from a multiple transmission antenna. Channel correlation measurer; A system capacity calculator for calculating a system measurement capacity for transmission antenna selection using information on a reception signal-to-noise ratio (SNR) of each reception channel of the multiple transmission antennas and the reception channel correlation; A transmit antenna combination selector for selecting a combination of transmit antennas at which the calculated system measurement capacity is maximized; A multi-user scheduler for scheduling a multi-user and the multi-transmit antenna in accordance with the selected transmit antenna combination; And a scheduling information transmitter for transmitting the scheduling information in the scheduling step to the multiple transmit antennas.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram schematically illustrating a multiple input multiple output system in uplink of a wireless communication system according to an exemplary embodiment of the present invention.

개의 송신 안테나 중 M(≤N)개의 송신 안테나(104, 105, 106)를 선택하여 송신하도록 하고, 선택된 송신 안테나(104, 105, 106)들로부터 신호를 N개의 수신 안테나(107, 108)로 수신하는 구성을 갖는다. 이하 본 명세서에서는 선택되기 전의 송신 안테나와 관련한 값은 첨두 기호(～)를 붙여서 표현하고, 선택된 송신 안테나와 관련한 값은 첨두 기호(～) 없이 표현하기로 한다. In the uplink of the MIMO wireless communication system as shown in FIG. 1, the base station 109 having N receive antennas uses a total of U users 101 and 102 using one or a plurality of transmit antennas at an arbitrary scheduling time. Total of 103)

M (≤ N) transmit antennas 104, 105, and 106 are selected to transmit, and signals are transmitted from the selected transmit antennas 104, 105, and 106 to the N receive antennas 107, 108. Has a configuration to receive. Hereinafter, in the present specification, a value related to a transmission antenna before being selected will be represented by adding a peak symbol (˜), and a value related to the selected transmission antenna will be represented without a peak symbol (˜).

로 표현할 수 있다.In the MIMO wireless communication system as described above, the MIMO channel including the channel between the multiple transmit antennas and the multiple receive antennas has a matrix as shown in Equation 1 below.

Can be expressed as

은 m(1≤m≤M) 번째 송신 안테나와 다중 수신 안테나 사이의 채널 특성을 나타내는 (N×1) 벡터이며,

는 행렬

의 전치 행렬(transpose matrix)을 나타낸다. 이러한 채널을 통과하여 얻어진 (N×1) 수신 신호 벡터

는 다음 수학식 2와 같이 표현된다.here,

Is a (N × 1) vector representing channel characteristics between the m (1 ≦ m ≦ M) th transmit antenna and the multiple receive antenna,

Is a matrix

The transpose matrix of. (N × 1) received signal vector obtained through these channels

Is expressed by Equation 2 below.

는 (M×1) 송신 신호 벡터이며,

는 평균이 0(zero)이고 분산이 N₀인 복소 가우시안 잡음(complex Gaussian noise) (N×1) 벡터이다.Here, when the transmission signal of the m th transmission antenna of the selected M transmit antennas is x _m ,

Is the (M × 1) transmission signal vector,

Is a complex Gaussian noise with an average of zero and a variance of N ₀ (N × 1) Vector.

에 대한 (NM×1) 열 벡터를

로 정의하면, 시스템 채널 행렬

의 열 벡터 vec(

)는 다음 수학식 3과 같이 표현할 수 있다(D. Gesbert, H. Bolcskei, D. Gore 및 A. J. Paulraj 저, "MIMO wireless channels: Capacity and performance prediction," Proc. IEEE Global Communications Conf., pp. 1083-1088, Nov. 2003년 11월). (N × M) matrix

(NM × 1) column vector for

Defined by the system channel matrix

Column vector vec (

) Can be expressed as Equation 3 (D. Gesbert, H. Bolcskei, D. Gore and AJ Paulraj, "MIMO wireless channels: Capacity and performance prediction," Proc. IEEE Global Communications Conf., Pp. 1083). -1088, Nov. November 2003).

)는 다음 수학식 4와 같이 표시할 수 있다.In particular, if a correlation exists in the system's receive channel, vec (

) May be expressed as in Equation 4 below.

은 시스템의 채널 수신 상관도 행렬이고,

는 공간적으로 상관도가 없는 시스템 채널[즉, 평균이 0(zero)이고 분산이 1인 독립적이고 동일한 분포를 갖는(independent and identically distributed; IID) 복소 가우시안 채널] 행렬로 다음 수학식 5와 같은 (N×M) 행렬로 표현된다.here

Is the channel reception correlation matrix of the system,

Is a spatially uncorrelated system channel (i.e., an independent and identically distributed complex Gaussian channel with a mean of zero and a variance of 1) and is a matrix N × M) matrix.

이고 vec(

)는 다음 수학식 6과 같이

의 열 벡터를 나타낸다.here

And vec (

) Is as shown in Equation 6

Represents a column vector of.

은 다음 수학식 7과 같은 (NM×NM) 행렬로 표현된다.Channel Receive Correlation Matrix of the System

Is represented by a (NM × NM) matrix such as

는 행렬

의 복소전치 행렬(Hermitian matrix)을 나타내고, E{

}는

의 기대값 연산자(expectation operator)를 나타낸다. 여기서

은 m 번째 송신 안테나의 수신 채널 상관도 나타내는 (N×N) 행렬이다.At this time

Is a matrix

Denotes the Hermitian matrix, and E {

}

Expectation operator of. here

Is a (N × N) matrix that also represents the received channel correlation of the m th transmit antenna.

이라고 가정하면), 상기 수학식 7은 다음 수학식 8과 같이 표현된다.If we assume that the transmit channel correlation between transmit antennas is so small that it can be ignored (i.e. m ₁ ≠ m ₂ )

(7), the equation (7) is expressed by the following equation (8).

은 양의 준정부호(positive semi-definite) 특성을 갖는 헤르미션 행렬(Hermitian matrix)이므로 다음 수학식 9와 같이 특이치 분해가 (singular-value decomposition; SVD)가 가능하다.here

Since is a Hermitian matrix having a positive semi-definite characteristic, singular-value decomposition (SVD) is possible as shown in Equation 9.

과

은 각각

의 (N×N) 유니터리 행렬(unitary matrix)과 (N×N) 고유치 행렬(eigen-value matrix)을 나타낸다. 따라서 시스템 수신 채널 상관도 행렬 역시 다음 수학식 10과 같이 특이치 분해(SVD)가 가능하다.here

and

Are each

Denote an (N × N) unitary matrix and a (N × N) eigen-value matrix. Therefore, the system reception channel correlation matrix may also be singular value decomposition (SVD) as shown in Equation 10 below.

과

은 각각

의 (NM×NM) 유니터리 행렬과 (NM×NM) 고유치 행렬을 나타내며 각각 다음 수학식 11 및 수학식 12와 같이 표현된다.here

and

Are each

The (NM × NM) unitary matrix and the (NM × NM) eigenvalue matrix are shown in Equations 11 and 12, respectively.

의 열 벡터 vec(

)는 다음 수학식 13과 같이 표현되며, 시스템 채널

는 다음 수학식 14와 같이 표현된다.Therefore, substituting Equation 10 into Equation 4 results in a system channel.

Column vector vec (

) Is expressed as in Equation 13 below, and the system channel

Is expressed by Equation 14 below.

Therefore, an ergodic capacity of the MIMO system is given by Equation 15 below.

)는 행렬

의 행렬식을 나타내고,

는 (N×N) 단위 행렬(identity matrix)을 나타낸다. 또

는 송신 안테나 각각의 수신 신호대잡음비(signal-to-noise ratio: SNR)를 나타내는 M×M 대각 행렬(diagonal matrix)이며 다음 수학식 16과 같이 표현된다.Where det (

) Is a matrix

Represents the determinant of,

Denotes an (N × N) identity matrix. In addition

Is an M × M diagonal matrix representing a signal-to-noise ratio (SNR) of each of the transmitting antennas, and is represented by Equation 16 below.

과 P_m/M은 각각 m 번째 송신 안테나의 수신 SNR과 전력의 크기를 나타낸다. log₂det(·)는 오목 함수(concave function)이므로 측정 용량은 다음 수학식 17과 같은 상한값(upper bound)을 가진다.here

And P _m / M represent the received SNR and the power of the m th transmit antenna, respectively. Since log ₂ det (·) is a concave function, the measured capacitance has an upper bound as shown in Equation 17 below.

인 관계를 이용하면 다음 수학식 18과 같이 표현된다.Equation 17 is

Using the relation of is represented by the following equation (18).

과

의 분포는 각각

과

의 분포와 같으므로 (즉, 평균이 0이고 분산이 1인 복소 가우시안 분포이므로),

과

를 각각

과

으로 대체할 수 있다. 따라서 상기 수학식 18은 다음 수학식 19와 같이 표현된다.here

and

Distribution of each

and

Equal to the distribution of (i.e., a complex Gaussian distribution with mean 0 and variance 1),

and

Each

and

Can be replaced with Therefore, Equation 18 is expressed as Equation 19 below.

Using Equation 20 and Equation 21, Equation 18 may be expressed as Equation 22 below.

는 행렬

의 대각합(trace)을 나타내고,

은 총 M 개

중 한 개씩 따로 선택하여

을 생성하거나, L(≥2)개의 서로 다른 송신 안테나의 수신 채널 상관도 행렬들을 묶어서 선택하여 생성한

의 수가 모두 i 개인 집합을 원소로 가지는 집합을 나타내고,

는 집합

의 j 번째 원소 집합으로, 선택한

과

로 이루어진 집합의 tr(·) 안에 곱해져 있는 서로 다른 송신 안테나의 수신 채널 상관도 행렬들의 수가 동일한 형태인 집합을 원소로 가지는 집합이다.

는 집합

의 k 번째 원소 집합으로

또는

의 형태로 표현되는

을 l 번째 원소로 가진다. 또 여기서

는

의 tr(·)안에 곱해져 있는 서로 다른 송신 안테나의 수신 채널 상관도 행렬들의 수를 나타내고,

는 집합

의 원소의 수를 나타낸다.here

Is a matrix

Represents the trace of,

Silver M total

Select each one separately

Generated by combining the received channel correlation matrices of L (≥2) different transmit antennas

Represents a set whose elements are the set of all i s,

Set

Set of j th elements of, selected

and

Receive channel correlation of different transmit antennas multiplied in tr (·) of a set consisting of a set having elements having the same number of matrices.

Set

As the set of k th elements of

or

Represented in the form of

Has as the l th element. Here again

Is

Denotes the number of received channel correlation matrices of different transmit antennas multiplied in tr (·) of

Set

It represents the number of elements of.

For example, looking at the case of M = 4, each is represented by the following equation (23) to (25).

은 총 4개의

(즉,

)을 4개 모두 묶어서 선택하는 경우로

은 생성하지 않고

만을 1개 생성하는 경우이다. 이 경우는 상기 수학식 24와 같이

의 한 가지 밖에 없고, 이 때

의 원소 집합은 상기 수학식 25와 같이

의 1개이다. 다음으로 상기 수학식 23에서

는

과

의 수가 합쳐서 2개인 집합을 원소로 가지는 집합으로, 상기 수학식 24와 같이

을 3 개씩 묶고 1 개씩 묶는 경우(

)와

을 2개씩 묶고 2개씩 묶는 경우(

)의 2가지로 나뉜다. 이 때

의 원소 집합은 상기 수학식 25와 같이

,

,

,

의 4개가 있다. 마찬가지로

의 원소 집합은 상기 수학식 25와 같이

,

,

의 3개가 있다. 이와 같은 방식으로 상기 수학식 23의

은 상기 수학식 24와 같이

을 2개, 1개, 1개씩 묶는 1가지 경우(

)가 있고, 상기 수학식 23의

는 상기 수학식 24와 같이

을 1개, 1개, 1개, 1개씩 묶는 1가지 경우(

)가 있다. 여기서

의 원소 집합은 상기 수학식 25와 같이 총 6개(

)가 있으며,

의 원소 집합은 1개(

)만이 존재한다.First, in Equation 23

4 total

(In other words,

To bundle all four)

Without generating

This is the case when creating one bay. In this case, as in Equation 24,

There is only one thing at this time

The element set of is given by Equation 25

It is one of. Next, in Equation 23

Is

and

Is a set having two sets of elements as elements, as shown in Equation 24 above.

If you bundle 3 by 1 and then 1 by

)Wow

If you bundle two and bundle two

It is divided into two. At this time

The element set of is given by Equation 25

,

,

,

There are four of them. Likewise

The element set of is given by Equation 25

,

,

There are three of them. In this manner,

Is as shown in Equation 24 above.

1 case that bundles 2, 1, 1

), And

Is as shown in Equation 24 above.

1 case that bundles 1, 1, 1, 1

There is). here

The set of elements of a total of six (

),

Has one set of elements (

) Exists only.

When these are inserted into Equation 22, the measured capacitance in the case of M = 4 has an upper limit as shown in Equation 26 below.

That is, the maximum measurement capacity of the system is expressed as a function of the receive channel correlation of the selected transmit antenna, so that the base station transmits this value to the maximum (ie, the characteristics of the received channel correlation are orthogonal). It is desirable to select an antenna. Here, the meaning of 'transmission antennas in which the characteristics of the reception channel correlations are orthogonal to each other' refers to a transmission antenna having a maximum measurement capacity when the reception channel correlation of each transmission antenna is substituted in Equation 22 above. For example, when M = 4, the four transmit antennas of which Equation 26 is maximum are orthogonal to each other.

The method of selecting a transmission antenna according to the present invention includes various methods such as opportunistic fairness scheduling which gives all transmission antennas the same opportunity, proportional fairness scheduling which guarantees the same transmission rate proportionally to all transmission antennas, and the like. It can be implemented in combination with known scheduling methods. Hereinafter, a brief description will be made of an example in which the present invention is linked to a conventional equal opportunity scheduling method.

개의 모든 송신안테나에게 동일한 기회를 부여한다고 가정하면, 기지국에서

개의 송신 안테나의 수신 채널 상관도 정보를 가지고

번의 스케줄링 동안에 시스템 측정 용량의 합이 최대가 되는 송신 안테나의 조합을 선택하고 이를 스케줄링하면 측정 용량을 최대화할 수 있다. 총

개의 송신 안테나를 M개씩 선택하여

번의 스케줄링 동안 스케줄링 하는 방법의 수를

이라 하면 이는 다음 수학식 27과 같다.first

Suppose all the transmitting antennas are given the same opportunity.

Receiving channel correlation information of two transmit antennas

Selecting and scheduling a combination of transmit antennas where the sum of the system measurement capacities is maximum during one scheduling can maximize the measurement capacities. gun

Select M transmit antennas

How many times to schedule during

This is expressed by Equation 27 below.

개의 방법 중

번째 방법에서 t번째 스케줄링 시간에 얻을 수 있는 측정 용량을

라고 하면, 이는 상기 수학식 22에서 유도한 상한값으로 계산되므로, 이를 이용하면 최적의 송신 안테나 조합의 선택 및 스케줄링 방법

를 다음 수학식 28과 같이 얻을 수 있다.gun

Of ways

In the second method, the measured capacity that can be obtained at the tth scheduling time

In this case, since this is calculated as the upper limit derived from Equation 22, using this method, an optimal transmission antenna combination selection and scheduling method

Can be obtained as in Equation 28 below.

2 is a diagram conceptually showing a method of selecting a transmit antenna in uplink according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating an example of user scheduling according to the method of selecting a transmit antenna shown in FIG. One drawing.

As shown in FIG. 2, six users 201 to 206 transmit signals to a base station having four receive antennas 221 to 224 through a total of 12 transmit antennas 207 to 218, as described above. Similarly, a combination of transmission antennas in which reception channel correlations are orthogonal to each other is, for example, a first transmission antenna 207 of the first user 201 and a fourth transmission antenna 210 of the third user 203, respectively. , The seventh transmit antenna 213 of the fourth user 204 and the tenth transmit antenna 216 of the fifth user 205.

While the selection of a transmitting antenna by the conventional cyclic order method randomly selects and transmits transmitting antennas in a cell at an arbitrary scheduling time, the transmitting antenna selecting method according to the present invention is an antenna in which receiving antenna correlation characteristics are orthogonal to each other. The combinations 207, 210, 213, and 216 may be selected and transmitted first, and the remaining transmission antennas may be arbitrarily selected and transmitted during the remaining scheduling time. That is, as shown in Fig. 3, the transmission antennas 1, 4, 7, and 10, which are combinations of transmission antennas having different reception antenna correlation characteristics, are selected at the first scheduling time, and transmission antennas 2, 5, 8, and 11 are selected. The second scheduling time is selected, and transmission antennas 3, 6, 9, and 12 may be selected as the third scheduling time. Here, the order of time of the first, second, and third scheduling may be changed in combination with various conventional scheduling methods such as equal opportunity scheduling or proportional equal scheduling. In this example, an example of proportional equal scheduling is considered.

4 is a diagram schematically illustrating a part of a configuration of a base station including an apparatus for selecting a transmit antenna in uplink according to an embodiment of the present invention.

The transmission antenna selector 413 in the uplink according to the present invention includes a signal-to-noise ratio measurer 406 for measuring the signal-to-noise ratio of each reception channel, and a reception channel correlation diagram for measuring the channel correlation of the base station reception signal in the uplink. A measuring instrument 407, a system measuring capacity calculator 408 that calculates a system measuring capacity using the received channel correlation, and a transmission antenna combination for selecting the maximum measuring capacity of the system calculated by the system measuring capacity calculator; Transmitting antenna combination selector 409, a multi-user scheduler 410 for scheduling a user and all transmit antennas according to the transmit antenna combination selected by the transmit antenna combination selector, and scheduling information by the multi-user scheduler to the user. 411. The base station including the transmitting antenna selection device 413 in the uplink according to the present invention also includes a receiving antenna 401, a transmitting antenna 412, a data symbol extractor 402, a pilot symbol extractor 403, a channel. Estimator 404, data demodulator 405, and the like.

FIG. 5 is a flowchart illustrating a method of selecting a transmit antenna in uplink according to an embodiment of the present invention. Hereinafter, referring to FIGS. 4 and 5 in the uplink according to an embodiment of the present invention. A transmission antenna selection method will now be described.

First, in steps 501 and 502, the received signal-to-noise ratio measuring instrument 406 and the receiving channel correlation measurer 407 receive the received signals transmitted by the multiple transmit antennas of the user from the multiple receive antennas 401 of the base station. Receive signal-to-noise ratio and receive channel correlation information for the channel. Information on the received signal-to-noise ratio and the received channel correlation of these multiple transmit antennas may be estimated using an uplink channel prediction signal or estimated using a downlink pilot signal.

Subsequently, in step 503, the system measurement capacity calculator 408 calculates the system measurement capacity for the transmission antenna combination selection as described above using the received signal-to-noise ratio and the received channel correlation information of the reception channel measured in steps 502 and 503. In step 504, the transmitting antenna combination selector 409 selects the transmitting antenna combination having the largest system measuring capacity calculated by the system measuring capacity calculator 408. The optimal transmit antenna combination is selected and delivered to the multi-user scheduler 410.

In step 505, the multi-user scheduler 410 determines a scheduling method for all users and all transmit antennas according to the optimal transmit antenna combination received from the transmit antenna combination selector 409. In step 506, the multi-user scheduler ( Information from 410 is delivered to the user via the scheduling information transmitter 411 and the transmit antenna 412 of the base station.

 The transmission selection method according to the present invention can be applied in various other ways. Hereinafter, preferred examples thereof will be described. However, in the following description, only parts necessary for understanding the application method according to the present invention will be described, and in addition, the overlapping configuration corresponding to FIG. 5 will be represented by the same reference numerals. In addition, hereinafter, a detailed description of a transmission antenna selection device for implementing an application method according to the present invention will be omitted for convenience, but those skilled in the art will be described with reference to the components shown in FIG. It will be appreciated that the present invention can be configured to be included in a transmission antenna selection device according to the present invention.

First, in order to reduce the selection complexity of the base station, the transmission antenna selection method according to the present invention is applied only to transmission antennas having a high reception channel correlation, which can obtain a large performance gain through the transmission antenna selection method according to the present invention. Transmission antennas having a small channel correlation may use a conventional transmission antenna selection method. FIG. 6 illustrates an example of a transmission antenna selection method according to an embodiment of the present invention used in combination with a conventional antenna selection scheme. Doing.

의 스펙트럴 놈(spectral norm)을

으로 정의하면, 도 6과 같이 기지국에서는 송신 안테나의 선택 시 각 송신 안테나의 수신 채널 상관도

과

의 스펙트럴 놈은 다음 수학식 29 및 수학식 30과 같이 주어진다.procession

The spectral norm of

6, when the base station selects a transmission antenna, the reception channel correlation diagram of each transmission antenna is shown.

and

The spectral norm is given by Equations 29 and 30 below.

을 구한다(도 6의 단계 601). 여기서

와

는 각각

번째 송신 안테나의 수신 채널 상관도

의 최대 및 최소 고유치를 나타낸다. 이로부터

번째 송신 안테나의 수신 채널 상관도의 고유치 확산값은 다음 수학식 31과 같이 얻을 수 있다.Eigen-value spread values of the received channel correlations from Equations 29 and 30

(Step 601 of FIG. 6) is obtained. here

Wow

Are each

Channel correlation of the first transmit antenna

Represents the maximum and minimum eigenvalues of. From this

The eigenvalue spread value of the received channel correlation of the first transmit antenna can be obtained as shown in Equation 31 below.

은 항상 1 이상의 값을 가지며, 이 값이 클수록 수신 채널 상관도가 큼을 의미한다. 기지국에서는 도 6의 단계 602에서 고유치 확산값

과 소정의 문턱값(threshold)과 비교하여,

이 문턱값보다 크면 본 발명에 따른 송신 안테나 선택방법을 적용하고(단계 503), 아니면 종래의 송신 안테나 선택 방법을 적용함으로써(단계 603), 본 발명에 따른 송신 안테나 선택 방법을 그대로 적용하는 것에 비해 선택 복잡도를 줄이면서도 비슷한 성능을 얻을 수 있게 된다. here

Always has a value greater than or equal to 1, and a larger value means that the reception channel correlation is greater. The base station spreads the eigenvalue spread value in step 602 of FIG.

And compare with a predetermined threshold,

If it is larger than this threshold, by applying the transmission antenna selection method according to the present invention (step 503), or by applying the conventional transmission antenna selection method (step 603), compared to applying the transmission antenna selection method according to the present invention as it is. Similar performance can be achieved with reduced selection complexity.

개의 송신 안테나를 몇 개의 그룹으로 나누어 그룹 내의 선택은 본 발명에 따른 송신 안테나 선택 방법을 적용하고 그룹 간의 선택은 종래의 선택 방법을 적용할 수 있다. 즉,

개의 송신 안테나를 각각

개의 송신 안테나로 구성되는 k개의 그룹으로 나누어, 각각의 그룹 내의 송신 안테나들에 대해서는 본 발명에 따른 송신 안테나 선택방법을 적용하고 그룹과 그룹 사이의 선택은 종래의 선택 방법을 적용함으로써 선택 복잡도를 줄일 수 있다.Second, as another way to reduce the selection complexity of the base station

The transmission antenna selection method according to the present invention can be selected by dividing the three transmission antennas into several groups, and the conventional selection method can be applied between the groups. In other words,

Each transmit antenna

The transmission antenna selection method according to the present invention is divided into k groups consisting of four transmission antennas, and transmission antennas in each group The selection between groups and groups can reduce the selection complexity by applying a conventional selection method.

Third, in using the method of selecting a transmission antenna according to the present invention, the number M of transmission antennas selected by a base station can be variably adjusted according to circumstances. 7 is a diagram illustrating a method of variably adjusting the number of transmit antennas according to an embodiment of the present invention.

Referring to FIG. 7, the system measurement capacity is calculated using the signal-to-noise ratio and the reception channel correlation measured in steps 501 and 502 (step 503), and the system in various cases according to the number of transmission antennas selected and the selection method. Calculate the measured dose. Thereafter, by using the system measurement capacity calculated in step 503, the decrease in system measurement capacity due to the system burden according to the number of transmission antennas selected in step 701 is added, and the system measurement capacity according to the number of transmission antennas selected in step 701. If the system measurement capacity in the case where the reduction is reflected has a maximum value, determine the optimal number of transmit antennas and the optimal selection method (step 702), and select the optimal transmit antenna combination according to the selected number of transmit antennas determined in this way. (Step 504).

가지 경우에서 최대 측정 용량을 얻는 방법

보다, 송신 안테나를 M₂개씩 선택하고 기회 균등 스케줄링 기법과 연동한

가지 경우에서 최대 측정 용량을 얻는 방법

의 측정 용량이 크다면 선택하는 송신 안테나의 개수를 M₂로 바꿀 수 있다. For example, as shown below, the transmit antennas are selected _{one by} one and linked with the equal opportunity scheduling technique.

To get the maximum measurement capacity

Rather, we select _two transmit antennas and link them with equal opportunity scheduling

To get the maximum measurement capacity

If the measurement capacity of is large, the number of transmission antennas to select may be changed to M ₂ .

는 다음 수학식 33과 같이 결정될 수 있다. That is, in the following Equation 32, an optimal transmission antenna combination selection method and scheduling method

May be determined as in Equation 33 below.

은 기지국에서 M_s 개의 송신 안테나를 선택할 경우의 시스템 부담으로 인한 시스템 용량 감소이다. 예를 들어, 시스템의 채널 추정 파일럿 설계 전략에 따라 1개의 송신 안테나를 선택하는 것보다 2개의 송신 안테나를 선택하면 파일럿 오버헤드가 2배가 될 수 있으며, 이를 고려하면 시스템 용량이 선택되는 송신 안테나의 개수에 따라 바뀔 수 있게 된다.here

Is a system capacity reduction due to system burden when M _s transmit antennas are selected at a base station. For example, depending on the channel estimation pilot design strategy of the system, selecting two transmit antennas may double pilot overhead than selecting one transmit antenna. Can change according to the number.

Fourth, the transmission antenna selected in the transmission antenna selection method according to the present invention may include not only the actual transmission antenna but also virtual transmission antennas 805 and 806. 8 is a diagram illustrating an example of a method of selecting a transmit antenna according to an embodiment of the present invention used in combination with the operation of a virtual transmit antenna.

)를 곱해 v_u 개의 가상적인 송신 안테나(805, 806)를 가지도록 만들 수 있다. 이 경우 시스템 전체의 송신 안테나 수가 가상적으로는 바뀌게 되지만 본 발명에 따른 송신 안테나 선택 방법은 용이하게 적용될 수 있다. Referring to FIG. 8, a u th user among the total U users 801 and 802 has p _u transmit antennas 803 and 804, and the base station 810 has M transmit antennas 808 and 809. Assuming that each user has a transmit weight vector (

Can be multiplied by) to have v _u virtual transmit antennas 805 and 806. In this case, the number of transmit antennas of the entire system is virtually changed, but the method of selecting a transmit antenna according to the present invention can be easily applied.

에

의 송신 가중치 벡터

를 곱함으로써 (v_u×1)의 가상적인 송신 신호 벡터

를 만들 수 있다. 따라서, 시스템의 채널 역시 가상 채널로 바뀌게 되며, 가상적인 송신 안테나의 수신 상관도 정보를 고려하여 본 발명에 따른 송신 안테나 선택 방법을 적용함으로써 시스템 용량을 증가시킬 수 있다. 또한 기지국에서는 사용자가 가진 송신 안테나의 수신 채널 상관도를 고려하여 시스템 용량이 증가될 수 있도록 송신 가중치 벡터

를 설계하여 하향링크(downlink) 채널을 통해 사용자에게 알려줌으로써 시스템 용량을 더욱 증가시킬 수도 있다.That is, the transmission signal vector of (p _u × 1)

on

Send weight vector

Virtual transmission signal vector of (v _u × 1)

Can make Therefore, the channel of the system is also changed to a virtual channel, the system capacity can be increased by applying the transmission antenna selection method according to the present invention in consideration of the reception correlation information of the virtual transmission antenna. In addition, the base station transmits a transmission weight vector to increase the system capacity in consideration of the reception channel correlation of the user's transmission antenna.

It can be designed to inform the user through the downlink channel to further increase the system capacity.

Fifth, if the receiving antenna of the base station supports multiple cells and multiple sectors, the proposed antenna selection scheme may be applied by grouping antennas supporting multiple cells and sectors. 9 is a diagram illustrating a case where a transmission antenna selection method according to an embodiment of the present invention is applied when a base station supports multiple sectors. As shown in FIG. 9, the present invention provides three sectors (sectors), for example, where the receiving antennas 914; 915; 916 of the base station support users 901 to 905; 906 to 910; 911 to 912, respectively. The transmission antenna selection method according to the present invention may also be applied to the case of 1; sector 2; sector 3).

If the number of cells and sectors in which reception channel correlations can be exchanged with each other is B and the number of reception antennas of the b-th cell and sector is N _b , the total number N of reception antennas is given by Equation 34 below. .

라고 하면, 송신 안테나의 총 수

은 다음 수학식 35와 같이 된다.And the number of transmit antennas in the b-th cell and sector

, The total number of transmit antennas

Is as shown in Equation 35 below.

Accordingly, it can be seen that the transmission antenna selection method according to the present invention can be easily applied even in a multi-cell and sector environment. In particular, in case of an antenna having a high channel reception correlation between receiving antennas located at the boundary of a cell and a sector, More efficient.

10 is a diagram illustrating a result of evaluating an increase in system measurement capacity through a method of selecting a transmission antenna in uplink according to the present invention. It is assumed that the number of receiving antennas of the base station is N = 2, and the uplink multiple input multiple output system selects M = 2 transmitting antennas at an arbitrary scheduling time. In order to simplify performance evaluation, all users have the same average SNR, and statistical characteristics of the channel, such as the reception channel correlation of each transmission antenna, are fixed, so that the reception channel correlation of each transmission antenna in the (2 × 2) system is Assume that this is represented by a (2 × 2) matrix as shown in 36.

The upper limit of the measured capacitance according to the selected transmission antenna of Equation 22 is expressed by Equation 37 below.

= 4로 두었다. 또 각 안테나에 대해

= 0.95,

= 0.95j,

= -0.95,

= -0.95j로 가정하였으며, 여기서

을 나타낸다. 기회 스케줄링 기법과 연동될 경우, 상기 수학식 27로부터

= 2번의 스케줄링 시간 동안 선택하는 방법의 수 G₂ = 3이며 그 중 측정 용량이 최대가 되는 송신 안테나 선택 방법

는 1번째 스케줄링 시간에 (

,

) = (

,

)이 되도록 1 번째 송신 안테나와 3 번째 송신 안테나를 선택하고, 2번째 스케줄링 시간에 (

,

) = (

,

)이 되도록 2번째 송신 안테나와 4번째 송신 안테나를 선택하는 방법이다. 즉, M = 2인 경우 상기 수학식 37이 최대가 되도록 하는 수신 상관도가 서로 직교적인 조합을 선택하는 방법이며, 수학적으로는

과

의 위상 차이가 180도에 가까운 조합을 선택하는 방법이다. 특히 이와 같이 수신 안테나의 개수가 2개인 경우에서는 기지국에서 각 송신 안테나의 수신 채널 상관도 행렬

전체가 아니라

만을 알면 되므로 연산 복잡도를 더욱 줄일수 있다. 실험 결과를 통해 본 발명에 따른 송신 안테나 선택 방법의 경우 종래의 순환 순서 방식의 선택 방법에 비해 시스템 측정 용량이 증가함을 확인할 수 있다.Total number of transmit antennas in the cell

= 4 In addition, about each antenna

= 0.95,

= 0.95j,

= -0.95,

= -0.95j, where

Indicates. When linked with the opportunity scheduling scheme, the equation (27)

= Number of methods to select during 2 scheduling times G ₂ = 3 and the method of selecting the transmit antenna with the largest measured capacity

At the first scheduling time (

,

) = (

,

Select the first transmit antenna and the third transmit antenna to be), and at the second scheduling time (

,

) = (

,

In this case, the second transmit antenna and the fourth transmit antenna are selected. That is, when M = 2, a method of selecting orthogonal combinations of reception correlations such that Equation 37 is maximized, and mathematically,

and

Is to select a combination whose phase difference is close to 180 degrees. In particular, when the number of receiving antennas is two as described above, the reception channel correlation matrix of each transmitting antenna is performed by the base station.

Not whole

Because you only need to know that, you can reduce the computational complexity further. Experimental results show that the transmission antenna selection method according to the present invention increases the system measurement capacity compared to the conventional cyclic order selection method.

While the preferred embodiment of the present invention has been described above, other 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 appended claims, but also by the equivalents of the claims.

In a multi-input multi-output wireless communication system environment where the reception channel correlation of antennas is present, the conventional transmission antenna selection method has an overhead problem of channel estimation and prediction signals, a channel mismatch problem in a fast environment, and a reception channel between transmission antennas. Although there is a problem of performance deterioration due to the correlation, according to the present invention, especially in an uplink environment of a MIMO system in which a reception channel correlation of an antenna exists, the overhead of channel estimation and prediction signals is little compared to that of the conventional method. The effect is to increase the measuring capacity of the system even in a fast environment.

Claims (16)

A method for selecting a multi-user transmit antenna in an uplink of a multi-user multi-input multi-output wireless communication system, Receiving information on a reception channel correlation of a base station from multiple transmission antennas of multiple users; A system of a multi-user uplink multi-input multi-output system for selecting a transmit antenna of a multi-user by using the received signal-to-noise ratio (SNR) of each receive channel of the multi-transmit antenna of the multi-user and information on the received channel correlation Calculation of the measuring capacity Selecting a combination of multi-user transmit antennas having a maximum measurement capacity of the multi-user uplink multi-input multi-output system Scheduling the multi-user and the multi-transmit antenna according to the selected multi-user transmit antenna combination; and And transmitting the scheduling information in the scheduling step to a multi-user having the multi-transmit antenna. delete The method of claim 1, The method of calculating a system measurement capacity is calculated by the following equation, wherein a multi-user transmit antenna selection method in an uplink of a multi-user multi-input multi-output wireless communication system.

here,

Is the system channel matrix,

Is a matrix representing the received channel correlation of the m th transmit antenna,

Is the received signal-to-noise ratio of the mth transmit antenna of multiple users,

Is a matrix

Suppose we have a trace of,

Select one of the total M

Generated by combining the received channel correlation matrices of L (≥2) different transmit antennas

Represents a set whose elements are the set of all i s ,

Set

Is the set of j th elements of

and

Receive channel correlation of different transmit antennas multiplied in tr (·) of a set consisting of

Set

As the set of k th elements of

or

Represented in the form of

Has as the l th element,

Is

Represents the number of received channel correlation matrices of the transmit antennas of different multi-users multiplied in tr (·) of

Set

Indicates the number of elements in. delete The method of claim 1, In the scheduling step, the transmission antenna selection of the multi-user in the uplink of the multi-user multi-input multi-output wireless communication system is determined using a scheduling method as shown in the following equation. Way.

here,

Is the total number of transmit antennas, M is the number of selected transmit antennas,

Is expressed as

Select M transmit antennas

Of scheduling during one scheduling

Represents the system measurement capacity that can be obtained at the t th scheduling time in the second method.

The method of claim 1, After receiving the information about the received channel correlation, Calculating a spectral norm and an eigen-value spread of the received channel correlation using the information on the received channel correlation; and And comparing the calculated eigenvalue spread value of the received channel correlation with a threshold value. And calculating the system measurement capacity only when the eigen spread is greater than or equal to a threshold value. The method of claim 1, wherein the multi-user multi-input multi-output wireless communication system is uplink. delete The method of claim 1, The calculating of the system measurement capacity may include calculating the system measurement capacity according to the number of transmission antennas and the selection method of the transmission antenna combination of the selected multiple users, The method, Adding a decrease in system measurement capacity due to system burden according to the number of transmission antennas selected from the system measurement capacity according to the number of transmission antennas and the selection method calculated in the calculating of the system measurement capacity; And determining a selection method of maximizing a system measurement capacity in which the measurement capacity decrease according to the number of the selected transmission antennas is maximized in the uplink of the multi-user multi-input multi-output wireless communication system. Transmission antenna selection method. delete The method of claim 1, The number of transmit antennas of the u th user among the total U users

Is the physical transmission signal vector of the u th user.

on

Send weight vector

By multiplying

Virtual transmission signal vector

A method for selecting a transmit antenna of a multi-user in uplink of a multi-user multi-input multi-output wireless communication system, characterized in that it comprises a virtual transmit antenna, characterized in that it is generated using. delete delete An apparatus for selecting a multi-user transmit antenna in an uplink of a multi-user multi-input multi-output wireless communication system, Receive Channel Correlation Meter for receiving information on the receive channel correlation of the base station from multiple transmit antennas of multiple users Measurement of a multi-user uplink multi-input multi-output system for selecting a transmit antenna of a multi-user by using the received signal-to-noise ratio (SNR) of each receive channel of the multi-transmit antenna of the multi-user and information on the received channel correlation System measuring capacity calculator to calculate capacity A multi-user transmit antenna combination selector for selecting a combination of multi-user transmit antennas whose maximum measurement capacity of the multi-user uplink multi-input multi-output system is calculated A multi-user scheduler scheduling the multi-user and the multi-transmit antenna according to the selected transmit antenna combination; And a scheduling information transmitter for transmitting scheduling information in the scheduling step to multiple users having the multiple transmission antennas. The method of claim 13, The apparatus for calculating a system measurement capacity is calculated by the following equation.

here,

Is the system channel matrix,

Is a matrix representing the received channel correlation of the m th transmit antenna,

Is the received signal-to-noise ratio of the mth transmit antenna of multiple users,

Is a matrix

Suppose we have a trace of,

Select one of the total M

Generated by combining the received channel correlation matrices of L (≥2) different transmit antennas

Represents a set whose elements are the set of all i s ,

Set

Is the set of j th elements of

and

Receive channel correlation of different transmit antennas multiplied in tr (·) of a set consisting of

Set

As the set of k th elements of

or

Represented in the form of

Has as the l th element,

Is

Represents the number of received channel correlation matrices of the transmit antennas of different multi-users multiplied in tr (·) of

Set

Indicates the number of elements in. delete The method of claim 13, The multi-user scheduler selects a transmitting antenna of a multi-user in the uplink of the multi-user multi-input multi-output wireless communication system, using the scheduling method as follows: Device.

here,

Is the total number of transmit antennas, M is the number of selected transmit antennas,

Is expressed as

Select M transmit antennas

Of scheduling during one scheduling

Represents the system measurement capacity that can be obtained at the t th scheduling time in the second method.

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