KR20190049337A - Design of mimo system with uniform circular array over los channel and designing apparatus and method thereof - Google Patents

Abstract

Proposed are a multi-input multi-output (MIMO) system using a circular array in a line of sight (LOS) channel environment, an apparatus for designing the MIMO system, and a method for designing the MIMO system. According to an embodiment of the present invention, the method for designing an MIMO system using a circular array in a LOS channel environment comprises the steps of: calculating a channel coefficient of the circular array; estimating a channel matrix of the circular array by converting the channel coefficient into a determinant; and obtaining an optimal radius of the circular array for obtaining the maximum channel capacity in the channel matrix, wherein the optimal radius can obtain the maximum frequency efficiency in the LOS channel.

Description

TECHNICAL FIELD The present invention relates to a multi-antenna system using a circular array antenna in a visible channel environment,

The present invention relates to a multi-antenna system using a circular array antenna in a visible channel environment, and more particularly to a multi-antenna system using a circular array antenna in a line-of-sight channel environment, and more particularly, And more particularly to a multi input multiple output (MIMO) system using a uniform circular array (UCA) antenna.

Recently, as the commercial communication band shifts to the millimeter wave band, research on the communication system in the visible channel environment is increasing. Particularly, a technology for realizing a high-speed transmission using a uniform circular array antenna in a visible-line environment has been researched steadily. Uniform circular array antennas have discrete Fourier transform (DFT) and discrete Fourier transform (DFT) without channel information at the transmitting / receiving end because the transmitting / receiving channel matrix becomes a circulating matrix unlike the conventional uniform linear array (ULA) The inverse discrete Fourier transform (IDFT) can easily diagonalize the channel matrix. This property is useful for designing an actual transceiver stage because it is established irrespective of the antenna array radius or transmission distance. In addition, since this characteristic can be applied to a system using a subarray antenna, the design of the beamformer can be simplified.

According to recent research results, spatial multiplexing gain can be obtained through optimized antenna arrangement in the channel environment of visible line. According to these results, the optimal antenna arrangement satisfies the condition that the channel is an orthogonal matrix, which can be expressed as a function of the transmission frequency, the array size, and the transmission distance. When this condition is satisfied, the channel becomes an orthogonal matrix and has the same singular values, and as a result, the maximum frequency efficiency can be obtained at a limited transmission power. The optimum antenna placement condition depends on the antenna array type. In a uniform linear array antenna system, the distance between the antennas required for the optimized antenna arrangement increases as the communication distance increases. In a uniform circular array antenna system, the diameter of the circular array antenna is proportional to the transmission distance. If the number of antennas is 4 or less, the channel matrix becomes an orthogonal matrix if the following condition is satisfied.

[Equation 1]

는 반송파 주파수 파장을 나타낸다. 그러나 안테나 개수가 4개보다 커지게 되면 위 조건이 성립하지 않는다. 또한, 제안된 최적의 안테나 배치는 송수신단 균일 원형 안테나 배열의 중심 축이 일치하고 배열면이 완벽하게 평행한 상황을 가정한다. 실제 환경에서는 이와 같은 가정이 성립하기 어렵기 때문에 정렬 불량인 경우에 대한 최적의 안테나 배치 방법에 대해 연구가 진행되고 있다. 기존 연구들은 주로 선형 배열 안테나 및 직사각형 형태의 배열 안테나에 대한 것으로 아직 원형 배열 안테나에 대해서는 연구된 바가 없다. Where R is the radius of the circular array antenna, D is the communication distance,

Represents the carrier frequency wavelength. However, if the number of antennas becomes larger than 4, the above condition does not hold. In addition, the proposed optimal antenna arrangement assumes a situation where the center axes of the uniform circular antenna array of transmitting and receiving ends coincide and the array surfaces are perfectly parallel. In this paper, we propose an optimal antenna placement method in case of misalignment. Previous studies have focused on linear array antennas and rectangular array antennas.

Korean Patent No. 10-0785852 discloses a multi-antenna system using a circular array antenna in a subchannel allocation and fixed beamforming transmission line channel environment for maximizing transmission efficiency in such an orthogonal frequency division multiple access based wireless communication system, And a description of the method.

Korean Patent No. 10-0785852

Embodiments describe a multi-antenna system using a circular array antenna in a line-of-sight channel environment and a designing apparatus and method thereof, and more specifically, a technique for obtaining a maximum frequency efficiency at a given number of antennas at a target transmission distance.

Embodiments can obtain a maximum frequency efficiency at a target transmission distance when designing the radius of a uniform circular array antenna and can also be applied to a circular array antenna with a poor alignment, And a designing apparatus and method thereof.

A method of designing a multi-antenna system using a circular array antenna in a visible channel environment according to an exemplary embodiment of the present invention includes: estimating a channel coefficient of a circular array antenna; Estimating a channel matrix of the circular array antenna by converting the channel coefficients into a matrix; And obtaining an optimal radius of the circular array antenna for obtaining a maximum channel capacity in the channel matrix, wherein the optimal radius can obtain the maximum frequency efficiency in the line-of-sight channel.

The step of estimating the channel coefficient of the circular array antenna may calculate the channel coefficient through a distance between a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas.

The circular array antenna may be a circular array antenna having a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas and each having five or more antennas.

Wherein the step of obtaining the optimal radius of the circular array antenna for obtaining the maximum channel capacity in the channel matrix is performed by finding a value that minimizes a sum of absolute values of inner products of column vectors of the circular array antenna, And obtaining an optimal radius.

The step of obtaining the optimal radius at the target transmission distance may be a unitary matrix such that the singular values of the channels are all equal in order to obtain the maximum channel capacity in the channel matrix.

The step of obtaining the optimal radius at the target transmission distance may be performed such that the sum of the absolute values of the inner product of the column vectors of the channel is a partial convex function form so that the optimal value is obtained by using the smallest value You can get the radius.

The circular array antenna includes a transmitting end circular array antenna and a receiving end circular array antenna, and may be a uniform circular array (UCA) array in which the array of the transmitting end circular array antenna and the receiving end circular array antenna are aligned.

The circular array antenna includes a transmitting end circular array antenna and a receiving end circular array antenna, and the transmitting end circular array antenna and the receiving end circular array antenna may be a uniform circular array (UCA) with an alignment defect.

Wherein when the receiving end circular array antenna is rotated at a predetermined angle in the xy plane relative to the transmitting end circular array antenna and when the receiving end circular array antenna is inclined in two directions, And a case where the center axis of the antenna is shifted by a predetermined angle from the center axis of the transmitting end circular array antenna.

In an apparatus for designing a multi-antenna system using a circular array antenna in a visible channel environment according to another embodiment, a channel matrix of the circular array antenna is calculated, a channel matrix of the circular array antenna is calculated by converting the channel matrix into a matrix matrix, Mountain government; And a radius calculating unit for obtaining an optimal radius of the circular array antenna that obtains the maximum channel capacity in the channel matrix. The optimal radius can obtain the maximum frequency efficiency in the line-of-sight channel.

The channel estimation unit may estimate the channel coefficient through a distance between a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas.

Wherein the circular array antenna is a circular array antenna having a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas each having five or more antennas, The uniform circular array antenna (UCA) in which the array of the receiving end circular array antennas is aligned or the uniform circular array antenna (UCA) in which the transmitting end circular array antenna and the receiving end circular array antenna are misaligned .

Wherein the radius calculation unit calculates a radius that is the minimum of the sum of the absolute values of the inner product of the column vectors of the circular array antenna and obtains the optimal radius at the target transmission distance, A unitary matrix may be formed so that the singular values of the channels are all equal to each other.

In a multi-antenna system using a circular array antenna in a visible channel environment according to another embodiment, a transmission signal may be transmitted without a precoder and passing through a channel matrix with the same power.

And a receiver for receiving a signal with a conjugate transpose of the channel matrix.

The receiving end may be implemented as a zero-forcing receiver using a conjugate transpose of the channel matrix.

Wherein the transmitter calculates the channel matrix of the circular array antenna by calculating the channel coefficient of the circular array antenna, converts the channel matrix to a matrix, calculates the channel matrix of the circular array antenna, The radius can be obtained, and the maximum frequency efficiency can be obtained in the visible channel.

Wherein the circular array antenna is a circular array antenna having a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas each having five or more antennas, The uniform circular array antenna (UCA) in which the array of the receiving end circular array antennas is aligned or the uniform circular array antenna (UCA) in which the transmitting end circular array antenna and the receiving end circular array antenna are misaligned .

Embodiments can provide a multi-antenna system using a circular array antenna in a visible-line channel environment in which a maximum frequency efficiency is obtained at a given number of antennas at a target transmission distance and a transceiver is also simply implemented, and a designing apparatus and method thereof .

According to the embodiments, when designing the radius of the uniform circular array antenna, the maximum frequency efficiency can be obtained at the target transmission distance, and in the visible line channel environment applicable to the uniformly circular array antenna with the defective alignment, An antenna system and its designing apparatus and method can be provided.

FIG. 1 illustrates a uniform circular array antenna system in which a transmitting and receiving antenna array according to an embodiment is perfectly aligned.
FIG. 2 is a graph showing the sum of absolute values of inner products of all normalized column vectors according to an embodiment.
FIG. 3 illustrates a two-way tilted receiving end circular array antenna according to one embodiment.
FIG. 4 illustrates a system in which the center axis of the receiving end circular array antenna is moved according to an embodiment.
5 illustrates a transmit / receive end structure for a circular array antenna system in accordance with an embodiment.
6 is a flowchart illustrating a method of designing a multi-antenna system using a circular array antenna according to an embodiment of the present invention.
7 and 8 are graphs showing frequency efficiency according to an antenna radius according to an embodiment.
FIG. 9 shows frequency efficiency according to a method for implementing a transmitting / receiving end according to an embodiment.

Hereinafter, embodiments will be described with reference to the accompanying drawings. However, the embodiments described may be modified in various other forms, and the scope of the present invention is not limited by the embodiments described below. In addition, various embodiments are provided to more fully describe the present invention to those skilled in the art. The shape and size of elements in the drawings may be exaggerated for clarity.

The present invention relates to a multi-antenna system using a circular array antenna in a visible channel environment, and more particularly to a multi-antenna system using a circular array antenna in a line-of-sight channel environment, and more particularly, And more particularly to a multi input multiple output (MIMO) system using a uniform circular array (UCA) antenna.

Embodiments propose an optimal uniform circular array antenna design method for a multi-antenna system in a visible channel environment. In particular, embodiments suggest the optimal circular array antenna diameter at the target communication distance according to the number of antennas and the transmission frequency. When the radius of the uniform circular array antenna is designed by the method proposed in this embodiment, the maximum frequency efficiency can be obtained at the target transmission distance. The present embodiments are also applicable to a uniformly circular array antenna with a poor alignment. Also, we propose a transceiver structure for a uniform circular array antenna designed by the proposed method.

Fully aligned circular array antenna system

FIG. 1 illustrates a uniform circular array antenna system in which a transmitting and receiving antenna array according to an embodiment is perfectly aligned.

(송신 안테나

개, 수신 안테나

개) 균일 원형 배열 안테나 기반의 통신 시스템을 고려한다. In this embodiment, in the visible channel environment,

(radiator

Antenna, receiving antenna

Consider a communication system based on a uniform circular array antenna.

= 8의 균일 원형 배열 안테나 시스템의 3차원 좌표 위에서의 표현을 나타낸 것으로, 그 구조는 8개의 안테나(111, 121)들로 구성된 송수신단 원형 배열 안테나(110, 120)의 반경이 R로 동일한 균일 원형 배열 안테나 시스템이다. Referring to FIG. 1, for example, a transmitter /

= 8, wherein the radiuses of the transmitting and receiving end circular array antennas 110 and 120 constituted by the eight antennas 111 and 121 are equal to each other and equal to R It is a circular array antenna system.

만큼 떨어진 거리에 있으며, 송신단 원형 배열 안테나(110)의 평면과 서로 평행하고, 중심축은 모두 z축 위에 정렬되어 있다. 이 때, 채널 행렬

의 계수는 송수신 안테나 사이의 거리에 의해 결정되며, 다음 식과 같이 표현될 수 있다. Here, the plane of the transmitting end circular array antenna 110 is on the xy plane, and the receiving end circular array antenna 120 is

And parallel to the plane of the transmitting end circular array antenna 110, and the central axes are all aligned on the z-axis. At this time,

Is determined by the distance between the transmitting and receiving antennas, and can be expressed by the following equation.

&Quot; (2) "

는 송신단 m번째 안테나와 수신단 n 번째 안테나 사이의 거리를 나타내며, 다음 식과 같이 표현될 수 있다. here,

Represents the distance between the mth antenna of the transmitting end and the nth antenna of the receiving end and can be expressed by the following equation.

&Quot; (3) "

와

는 각각 송신단 안테나 사이의 배치 간격 및 수신단 안테나 사이의 배치 간격이다. here,

Wow

Are the spacing between the transmitting end antennas and the spacing between the receiving end antennas, respectively.

로 일정하고, 이 때 최대의 채널 용량을 얻기 위해서 채널의 특이값(singular value)이 모두 같아야 한다. The Frobenius norm of the channel matrix obtained through equations (2) and (3)

In order to obtain the maximum channel capacity, the channel should have the same singular value.

가 곱해진 유니타리 행렬(unitary matrix)이 되었을 때 채널의 특이값이 모두 같게 되고, 채널은 유니타리 행렬이 되기 위해서 모든 열벡터의 내적이 0이 되어야 한다. 채널 행렬의 k번째와 l번째 열벡터의 내적은 다음 식과 같이 나타낼 수 있다. Therefore,

When the unitary matrix is multiplied, the singular values of the channel become equal to each other. In order that the channel becomes a unitary matrix, the inner product of all column vectors must be zero. The inner product of the kth and lth column vectors of the channel matrix can be expressed as:

&Quot; (4) "

이다. here,

to be.

를

라 정의하면 모든 열벡터들의 내적의 절대값의 합은 다음 식과 같이 나타낼 수 있다.

To

, The sum of the absolute values of the inner product of all column vectors can be expressed by the following equation.

&Quot; (5) "

값에 대해 모든 열벡터들의 내적이 0이 되어야 한다. 따라서 모든 열벡터들의 내적의 절대값의 합이 0이 되는, 즉

이 되도록 하는

값이 찾고자 하는 값이다. In order for the channel to be a unitary matrix,

For values, the inner product of all column vectors must be zero. Therefore, when the sum of the absolute values of the inner products of all the column vectors becomes zero, that is,

To be

The value is the value you want to find.

값이 존재하나, 안테나 개수가 5개 이상일 경우

이 되도록 하는

값이 존재하지 않는다. If the number of antennas is three or four,

Value exists but the number of antennas is 5 or more

To be

The value does not exist.

이 최소가 되는

값을 찾아 목표 전송 거리에서 최적의 반경을 찾는 방법을 제공할 수 있다. 이 문제를 수식으로 서술하면 다음 식과 같이 나타낼 수 있다. In this embodiment, when the number of antennas is 5 or more, the sum of the absolute values of the inner products of all the column vectors

This is the minimum

Value to find the optimal radius at the target transmission distance. This problem can be expressed as the following equation.

&Quot; (6) "

는 부분적인 볼록 함수 형태이므로 함수의 극소점이 존재한다. 이 극소점을 얻을 수 있는 해 중에서 가장 작은 값을 이용하여 최적의 반경을 구할 수 있으며, 다음 식과 같이 나타낼 수 있다. At this time,

Is a partial convex function form, so there is a minimum point of the function. The optimal radius can be obtained by using the smallest value of the solution in which the minimum point can be obtained.

&Quot; (7) "

FIG. 2 is a graph showing the sum of absolute values of inner products of all normalized column vectors according to an embodiment.

일 때, 정규화 한 모든 열벡터들의 내적의 절대값의 합

를 나타낸다. 2, when the carrier frequency is 75 GHz and the target transmission distance

, The sum of the absolute values of the inner product of all normalized column vectors

.

의 최소값을 얻을 수 있는

는3.18이고, 이

값을 통해 얻어지는 최적의 균일 원형 배열 안테나의 반경은

이 된다.
At this time, the sum of the absolute values of the inner products of all the column vectors

To obtain the minimum value of

Is 3.18, and

The radius of the best uniform circular array antenna obtained by the value is

.

Poorly aligned circular array antenna system

The present embodiments are applicable not only to a uniform circular array antenna system in which the array of the transmitting and receiving ends is aligned, but also to a circular array antenna system with a poor alignment.

There are three cases of misalignment to be considered in this embodiment.

만큼 회전한 시스템을 고려한다. 수신단 원형 배열 안테나의 좌표는 다음 식과 같이 나타낼 수 있다. First, the receiving circular array antenna is compared with the transmitting circular array antenna in the xy plane

Consider a system that has been rotated as many times as possible. The coordinates of the receiving end circular array antenna can be expressed as follows.

&Quot; (8) "

이다.here,

to be.

Consider the following case where the receiving end circular array antenna is inclined. Ideally, the receive-end array antenna is on a plane parallel to the xy-plane and perpendicular to the xz-plane if the alignment of the receive-and-receive array is correct.

FIG. 3 illustrates a two-way tilted receiving end circular array antenna according to one embodiment.

만큼, 그리고 y축 방향으로

만큼 기울어질 수 있다. Referring to FIG. 3, there is shown a receiving end circular array antenna 310 which is tilted in two directions. For example, the receiving-end circular array antenna 310 inclined in two directions is arranged in the x-axis direction

And in the y-axis direction

. ≪ / RTI >

At this time, the coordinates of the receiving end antenna can be expressed by the following equation.

&Quot; (9) "

이고,

이다.here,

ego,

to be.

만큼 이동한 경우를 고려한다. Finally, the center axis of the receive-end array antenna is longer than the center axis of the transmit-

As shown in FIG.

FIG. 4 illustrates a system in which the center axis of the receiving end circular array antenna is moved according to an embodiment.

만큼 기울어진 방향으로

만큼 이동한 것을 나타낸다. 여기서, 수신단 원형 배열 안테나의 중심 좌표는

이다. 그리고 D는 송수신단 원형 배열 안테나 중심 사이의 거리를 나타낸다. 4, when the center axis of the receiving-end circular array antenna is located on the y-axis

In an oblique direction

. Here, the center coordinates of the receiving end circular array antenna are

to be. And D represents the distance between the centers of the transmitting and receiving end circular array antennas.

To simplify the representation of the coordinates, the direction in which the receiving end circular array antenna moves can be set as a new y'-axis. The new x'-axis is thus determined to be perpendicular to the y'-axis. If the center coordinates are expressed based on the new x'-axis and y'-axis, it can be expressed by the following equation.

&Quot; (10) "

If the coordinates of the nth antenna are obtained by using Equation (8) and Equation (9) based on the center coordinates, the following Equation can be obtained.

&Quot; (11) "

If the x'-axis and y'-axis are expressed in the x'-axis and the y'-axis, the coordinates of the nth antenna of the receiving end circular array antenna can be expressed as follows.

&Quot; (12) "

이고,

는

의

번째 원소이다. 마찬가지로, 송신단 원형 배열 안테나의 m번째 안테나의 좌표는

이다. 이 때,

이다. 이를 이용하여 송수신단 안테나 사이의 거리를 계산하면 다음 식과 같이 나타낼 수 있다. here,

ego,

The

of

The second element. Similarly, the coordinates of the m < th > antenna of the transmitting array antenna are

to be. At this time,

to be. The distance between the transmitting and receiving antennas can be calculated using the following equation.

&Quot; (13) "

이므로 1차 테일러 급수를 이용하여 근사를 하면 수학식 13은 다음 식과 같이 나타낼 수 있다.here,

(13) can be expressed by the following equation by approximating using the first-order Taylor series.

&Quot; (14) "

이다. 그리고

이다. here,

to be. And

to be.

Therefore, the channel coefficient when three misalignments occur can be expressed as the following equation.

&Quot; (15) "

Then, it can be expressed by the following equation.

&Quot; (16) "

,

, 그리고

는 (n, m)번째 원소가

인 채널 행렬이다. here,

,

, And

(N, m) < th >

Channel matrix.

Likewise, the channel matrix of a circular array antenna with a poor alignment must be zero internally of all column vectors in order to become a unitary matrix. The inner product of the kth and lth column vectors of the channel matrix can be expressed as:

&Quot; (17) "

는 크기가 1인 상수이고,

이다. here,

Is a constant of size 1,

to be.

은

,

일 때, 수학식 4의 절대값과 동일하게 된다. 실제 환경에서는

,

이므로 완벽하게 정렬된 원형 배열 안테나의 최적의 반경을 구하는 최적화 조건인 수학식 6과 동일한 조건으로 정렬 불량인 원형 배열 안테나 시스템의 최적의 반경을 얻을 수 있으며, 다음 식과 같이 나타낼 수 있다. The absolute value of Equation 17

silver

,

, It becomes equal to the absolute value of the equation (4). In a real environment

,

It is possible to obtain the optimal radius of the circular array antenna system with the defective alignment under the same condition as that of Equation 6, which is an optimization condition for obtaining the optimal radius of the perfectly aligned circular array antenna, and can be expressed by the following equation.

&Quot; (18) "

The following section describes a simple transceiver design.

가 곱해진 유니타리 행렬에 가깝게 된다. 이 때, 채널 행렬의 특이값은 거의 동등하게 얻어지므로 송신단에서 프리코더(precoder) 없이 동등한 크기의 전력 할당 방법으로 최적의 송신기를 구현할 수 있다. 또한 채널은 모두 서로 직교하게 되므로, 수신단은 제로 포싱(Zero Forcing) 수신기로 간단하게 구현 가능하다. 제로 포싱(Zero Forcing) 수신기 G는 다음 식과 같이 설계할 수 있다. In the case of designing a circular array antenna with a radius obtained using the proposed method according to the present embodiment,

Is close to the unitary matrix multiplied by. At this time, since the singular values of the channel matrix are almost equal, an optimal transmitter can be realized by a power allocation method of equal size without a precoder at the transmitting end. Also, since the channels are all orthogonal to each other, the receiver can be simply implemented as a zero-forcing receiver. Zero Forcing Receiver G can be designed as follows.

&Quot; (19) "

는 수신단에서 추정한 실제 시스템의 채널 행렬이고, 마지막 관계식은 채널 행렬이 유니타리 행렬에 가깝기 때문에 성립이 가능하다. 따라서 제안한 방법으로 설계한 원형 배열 안테나 시스템은 수신단을 채널 행렬의 켤레 전치(conjugate transpose)로 구현 가능하다. here,

Is the channel matrix of the real system estimated by the receiving end, and the last relation can be established because the channel matrix is close to the unitary matrix. Therefore, the circular array antenna system designed by the proposed method can be implemented as a conjugate transpose of the channel matrix.

5 illustrates a transmit / receive end structure for a circular array antenna system in accordance with an embodiment.

로 신호를 수신할 수 있다. 5, in a transmission / reception terminal structure for a circular array antenna system, a transmission signal 510 x is transmitted without a precoder at the same power, passes through a channel matrix 520 H, (530)

Lt; / RTI >

An example of a circular array antenna system will be described below.

A multi-antenna system using a circular array antenna in a visible channel environment according to an exemplary embodiment may include a transmitter and a receiver.

At the transmitting end, the transmitted signal can be transmitted without the precoder at the same power and can pass through the channel matrix. The transmitter estimates the channel coefficient of the circular array antenna by calculating the channel coefficient of the circular array antenna, converts the channel coefficient to the matrix, calculates the optimal radius of the circular array antenna that obtains the maximum channel capacity from the channel matrix, The maximum frequency efficiency can be obtained.

Here, the circular array antenna may be a circular array antenna having a transmitting-end circular array antenna including a plurality of antennas and a receiving-end circular array antenna including a plurality of antennas, each having five or more antennas.

In addition, the circular array antenna is composed of a uniform circular array (UCA) array in which the array of the transmitting circular array antenna and the receiving circular array antenna are aligned, or the transmitting circular array antenna and the receiving circular array antenna are arranged in a uniform circular array antenna (Uniform Circular Array: UCA).

The receiving end can receive the signal at the conjugate of the channel matrix. At this time, the receiver may be implemented as a zero-forcing receiver using a conjugate transpose of the channel matrix.

Herein, the circular array antennas of the transmitting and receiving ends are described above, and more specifically, a method and an apparatus for designing a multi-antenna system using the circular array antenna according to one embodiment will be described below.

Embodiments propose a method of designing an optimal radius of a uniform circular array antenna in a visible channel environment and the proposed method can be applied not only to uniform circular array antennas with perfect alignment but also to uniform circular antenna systems with poor alignment . The antenna system of the present embodiment can obtain maximum frequency efficiency for a given number of antennas at a target transmission distance and can obtain independent channel streams as many as the same number of antennas so that a transmitter can be easily designed without a precoder have. In addition, the receiver can be simply implemented as a zero-forcing receiver using a conjugate transpose of a channel matrix.

6 is a flowchart illustrating a method of designing a multi-antenna system using a circular array antenna according to an embodiment of the present invention.

Referring to FIG. 6, a method of designing a multi-antenna system using a circular array antenna according to an exemplary embodiment of the present invention includes a step of calculating a channel coefficient of a circular array antenna using a circular array antenna in a visible channel environment 610), a step 620 of calculating a channel matrix of the circular array antenna by converting the channel coefficients into a matrix equation, and a step 630 of obtaining an optimal radius of the circular array antenna that obtains the maximum channel capacity in the channel matrix Here, the optimal radius can obtain the maximum frequency efficiency in the visible line channel.

Here, the step of obtaining the optimal radius of the circular array antenna that obtains the maximum channel capacity in the channel matrix may be performed by finding a value in which the sum of the absolute values of the inner products of the column vectors of the circular array antenna is minimum, And obtaining an optimal radius.

Hereinafter, a method for designing a multi-antenna system using a circular array antenna according to an embodiment will be described in more detail with an example.

Meanwhile, an apparatus for designing a multi-antenna system using a circular array antenna according to an embodiment of the present invention may include a channel estimation unit and a radius estimation unit, which may be a single system or a separate system.

Hereinafter, a method for designing a multi-antenna system using a circular array antenna according to one embodiment will be described in detail through an apparatus for designing a multi-antenna system using a circular array antenna according to an embodiment of the present invention .

In step 610, the channel estimator may estimate the channel coefficient of the circular array antenna.

The channel estimation unit may estimate the channel coefficient through a distance between the transmitting end circular array antenna including a plurality of antennas and the receiving end circular array antenna including a plurality of antennas.

Here, the circular array antenna may be a circular array antenna having a transmitting-end circular array antenna including a plurality of antennas and a receiving-end circular array antenna including a plurality of antennas, each having five or more antennas.

For example, the circular array antenna may include a transmitting circular array antenna and a receiving circular array antenna, and may be a uniform circular array (UCA) array in which arrangements of the transmitting circular array antenna and the receiving circular array antenna are aligned.

In another example, the circular array antenna includes a transmitting end circular array antenna and a receiving end circular array antenna, and the transmitting end circular array antenna and the receiving end circular array antenna may be a uniform circular array (UCA) with a misalignment.

In this case, if the receiving circular array antenna is tilted in two directions when the receiving circular array antenna is rotated at a predetermined angle in the xy-plane as compared with the transmitting circular array antenna, And a case where the antenna is shifted by a predetermined angle with respect to the center axis of the transmitting end array antenna.

In step 620, the channel estimator may calculate the channel matrix of the circular array antenna by transforming the channel coefficients into a determinant.

In step 630, the radius calculator may determine an optimal radius of the circular array antenna that obtains the maximum channel capacity in the channel matrix.

The radius calculator may include a step of finding a value at which a sum of absolute values of inner products of column vectors of the channels of the circular array antenna is minimized and obtaining an optimum radius at the target transmission distance. For this purpose, the radius estimator may be a unitary matrix such that the singular values of the channels are all equal to obtain the maximum channel capacity in the channel matrix.

In addition, the radius calculation unit can obtain the optimal radius by using the smallest value among the solutions in which the sum of the absolute values of the inner product of the column vectors of the channel is a partial convex function, and can obtain the minimum point of the function.

According to embodiments, a method of designing an optimal radius of a uniform circular array antenna in a visible channel environment is provided, and it is applicable not only to uniform circular array antennas with perfectly aligned antennas but also to uniform circular antenna systems with poor alignment .

In order to show the effects and advantages according to the embodiments, the performance of the embodiment is confirmed through simulation.

The experimental environment can be expressed as the following equation. In a system that transmits 8 transmission data streams at the same time, the transmission power is adjusted so that the signal-to-noise ratio is 10 dB, and the carrier frequency is set to 75 GHz. The target transmission distance D is 100 m. In this simulation environment, the optimum radius of the circular array antenna at the transmitting / receiving end is 0.45 m obtained by using Equation (7).

First, it is confirmed whether the maximum frequency efficiency can be obtained at the optimum radius obtained by the proposed method.

7 and 8 are graphs showing frequency efficiency according to an antenna radius according to an embodiment.

In Figures 7 and 8, the transmitter considered two methods of power allocation (8x8 UCA equivalent power) to a size equivalent to an optimal power allocation method based on water-filling (8x8 UCA water filling). It is assumed that the receiver is implemented as an optimal receiver.

이다. Figure 7 illustrates the frequency efficiency of a perfectly aligned circular array antenna based system in accordance with one embodiment. And Figure 8 illustrates the frequency efficiency of a system with a poorly aligned circular array antenna according to one embodiment. The misalignment considered in Figure 8

to be.

The maximum frequency efficiency of about 26.4bit / s / Hz is obtained for both systems at the optimum radius of 0.45m found by the proposed method. 8 shows that a larger frequency efficiency is obtained when the radius is 0.66 m, but the actual difference is about 0.4 bit / s / Hz. Therefore, considering that the design goal is to obtain the maximum frequency efficiency at the minimum radius, It is reasonable to be a radius. Also, it can be confirmed that the frequency efficiency of the power transmission method using water filling that requires channel information at the transmitter in the optimal radius and the method of transmitting power distribution with the same size without channel information are almost the same. Therefore, This shows that the transmitter design is simple without information.

FIG. 9 shows frequency efficiency according to a method for implementing a transmitting / receiving end according to an embodiment.

값들이 모두 각각 평균이 0이고 범위가 -15°~ +15°인 연속균등분포(uniform distribution)를 이룬다고 가정하였다. Referring to FIG. 9, frequency efficiency according to a method of implementing a transmitting / receiving end of a circular array antenna system with poor alignment is shown.

Values are assumed to form a uniform distribution with an average of 0 and a range of -15 ° to + 15 °, respectively.

The comparison system can be composed of three types.

System 1 (SVD) is an optimal transceiver system implemented by sending channel information feedback to the transmitter using Singular Value Decomposition (SVD) of the channel matrix at the receiver.

System 2 (a conjugate transposition ZF receiver) is a system that implements a zero-forcing receiver with only the conjugate of the channel at the receiver without the transmitter precoder proposed in this embodiment.

System 3 (inverse matrix ZF receiver) is a system that implements a zero-forcing receiver with a pseudo-inverse of the channel, which is an existing method, at the receiver without a transmitter precoder.

The system 2 proposed in this embodiment can obtain the frequency efficiency almost equivalent to the frequency efficiency obtained in the system 1 requiring the channel information feedback of the transmitting end and the system 3 requiring the complicated calculation at the receiving end. Therefore, the above simulation results show that the system proposed in the present embodiment requires channel information at both the transmitting and receiving ends and does not have optimal transceiver and transmitter channel feedback implemented by complicated singular value decomposition. However, And can be a good alternative to the transceiver system implementing the receiver.

In sum, the circular array antenna system proposed in this embodiment shows the maximum frequency efficiency at a given number of antennas at the target transmission distance, and the transceiver can also be implemented simply.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, controller, arithmetic logic unit (ALU), digital signal processor, microcomputer, field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing apparatus may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device As shown in FIG. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (18)

A multi-antenna system design method using a circular array antenna in a visible channel environment,
Calculating a channel coefficient of the circular array antenna;
Estimating a channel matrix of the circular array antenna by converting the channel coefficients into a matrix;
Obtaining an optimal radius of the circular array antenna for obtaining a maximum channel capacity in the channel matrix
Lt; / RTI >
The optimal radius is to obtain the maximum frequency efficiency in the visible channel
Wherein the method comprises the steps of: The method according to claim 1,
Wherein the step of estimating the channel coefficient of the circular array antenna comprises:
Calculating the channel coefficient through a distance between a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas
Wherein the method comprises the steps of: The method according to claim 1,
In the circular array antenna,
A circular array antenna comprising a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas each having five or more antennas
Wherein the method comprises the steps of: The method according to claim 1,
Wherein the step of obtaining an optimal radius of the circular array antenna for obtaining a maximum channel capacity in the channel matrix comprises:
Finding a value at which a sum of absolute values of inner products of the column vectors of the circular array antenna is minimized and obtaining an optimum radius at a target transmission distance
The method comprising the steps of: 5. The method of claim 4,
Wherein the step of obtaining an optimal radius at the target transmission distance comprises:
In order to obtain the maximum channel capacity in the channel matrix, a unitary matrix is formed such that the singular values of the channels are all equal to each other.
Wherein the method comprises the steps of: 5. The method of claim 4,
Wherein the step of obtaining an optimal radius at the target transmission distance comprises:
The sum of the intrinsic values of the inner product of the column vectors of the channel is a partial convex function form, and the optimal radius is obtained by using the smallest value of the solution to obtain the minimum point of the function
Wherein the method comprises the steps of: The method according to claim 1,
In the circular array antenna,
A uniform circular array (UCA) antenna including a transmitting end circular array antenna and a receiving end circular array antenna, the array of the transmitting end circular array antenna and the receiving end circular array antenna being aligned
Wherein the method comprises the steps of: The method according to claim 1,
In the circular array antenna,
A transmitting end circular array antenna and a receiving end circular array antenna, wherein the transmitting end circular array antenna and the receiving end circular array antenna are uniform circular array antennas (UCA)
Wherein the method comprises the steps of: 9. The method of claim 8,
Wherein the uniformly circular array antenna with the misalignment has a non-
In the case where the receiving end circular array antenna is rotated in the xy-plane by a predetermined angle as compared with the transmitting end circular array antenna, when the receiving circular array antenna is inclined in two directions, And a case in which it is moved at a predetermined angle with respect to the central axis thereof
Wherein the method comprises the steps of: An apparatus for designing a multi-antenna system using a circular array antenna in a visible channel environment,
A channel estimator for estimating a channel matrix of the circular array antenna by calculating a channel coefficient of the circular array antenna and converting the channel matrix into a matrix; And
A radius calculating section for obtaining an optimal radius of the circular array antenna for obtaining a maximum channel capacity in the channel matrix,
Lt; / RTI >
The optimal radius is to obtain the maximum frequency efficiency in the visible channel
Wherein the antenna is a circular array antenna. 11. The method of claim 10,
The channel estimator may include:
Calculating the channel coefficient through a distance between a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas
Wherein the antenna is a circular array antenna. 11. The method of claim 10,
In the circular array antenna,
A circular array antenna having a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas, each having at least five antennas,
A uniform circular array antenna (UCA) in which the transmitting end circular array antennas and the receiving end circular array antennas are aligned, or a uniform circular array antenna (Uniform Circular Array Array: UCA)
Wherein the antenna is a circular array antenna. 11. The method of claim 10,
The radius calculation unit may calculate,
The channel matrix of the circular array antenna is obtained by finding a value that minimizes the sum of absolute values of inner products of the column vectors of the circular array antenna and obtaining an optimal radius at the target transmission distance, singular values are all equal to a unitary matrix
Wherein the antenna is a circular array antenna. In a multi-antenna system using a circular array antenna in a visible channel environment,
The transmission signal is transmitted without a precoder at the same power,
A multi-antenna system using a circular array antenna in a visible channel environment. 15. The method of claim 14,
A receiver for receiving a signal with a conjugate transpose of the channel matrix;
Wherein the multi-antenna system uses a circular array antenna in a visible channel environment. 16. The method of claim 15,
Wherein,
A zero-forcing receiver using a conjugate transpose of the channel matrix
A multi-antenna system using a circular array antenna in a visible channel environment. 15. The method of claim 14,
The transmitting end transmits,
Calculating a channel coefficient of the circular array antenna, calculating the channel matrix of the circular array antenna by converting the channel coefficient to a matrix formula, calculating an optimal radius of the circular array antenna that obtains the maximum channel capacity in the channel matrix, Obtaining the maximum frequency efficiency in the visible channel
A multi-antenna system using a circular array antenna in a visible channel environment. 18. The method of claim 17,
In the circular array antenna,
A circular array antenna having a transmitting end circular array antenna including a plurality of antennas and a receiving end circular array antenna including a plurality of antennas, each having at least five antennas,
A uniform circular array antenna (UCA) in which the transmitting end circular array antennas and the receiving end circular array antennas are aligned, or a uniform circular array antenna (Uniform Circular Array Array: UCA)
Wherein the multi-antenna system uses a circular array antenna.

Images