KR101813781B1 - Method of generating a pilot beam, and an apparatus performing the same - Google Patents

Abstract

A pilot beam generating method and apparatus for performing the same are disclosed. A pilot beam generation method according to an embodiment includes generating an output pilot beam based on characteristics of a hybrid MIMO transmission structure and a channel, and transmitting the output pilot beam.

Description

Field of the Invention [0001] The present invention relates to a pilot beam generating method,

The following embodiments relate to a pilot beam generating method and an apparatus for performing the same.

A millimeter wave communication system uses an antenna array composed of a large number of antennas in a transmitter / receiver to form a directional beam in order to overcome an increased path loss.

This increases the dimensionality of the transmitter and the receiver radio channel and causes a large burden on channel estimation. In order to solve the difficulty of channel estimation, a sparse channel estimation method for estimating a small number of paths using a millimeter wave channel composed of a small number of paths relative to the number of antennas has been proposed .

In the sparse channel estimation method, since the transmitter transmits the pilot signal for which the transmitter is promised, but the pilot signal transmission time is less than the number of antennas for the purpose of reducing the channel estimation burden, Orthogonality is not satisfied. In order to solve this problem, most sparse channel estimation methods use a scheme of designing pilots so as to approximate orthogonality with a high probability by utilizing a random pilot signal.

An example of an implementation scheme is to transmit a pilot beam composed of a random phase using a radio frequency (RF) phase shifter. The pilot beam, which is composed of a random phase, is an omnidirectional beam and transmits uneven irregular power in all directions. A pilot beam composed of random phases does not guarantee sufficient link budget for accurate channel estimation due to high path loss of the millimeter wave channel.

Embodiments may provide for generating a directional pilot beam reflecting the characteristics of a hybrid MIMO transmission structure and a millimeter wave channel.

A method for generating pilot beams according to an embodiment may include generating an output pilot beam based on characteristics of a hybrid MIMO transmission structure and a channel, and transmitting the output pilot beam.

The generating may comprise generating a baseband pilot beam, generating an RF pilot beam, and generating the output pilot beam based on the baseband pilot beam and the RF pilot beam.

The generating the RF pilot beam may comprise generating a plurality of RF pilot beams and determining a combination of the RF pilot beams from the plurality of RF pilot beams based on the characteristics of the channel.

The number of RF pilot beams included in the combination may correspond to the number of RF chains.

At least one of the baseband pilot beam and the RF pilot beam may be generated such that the columns of the sensing matrix for estimating the millimeter wave channel have a low correlation.

The millimeter wave channel may be a millimeter wave channel sparse representation by a dictionary.

The dictionary may be constructed based on non-uniform quantization.

The dictionary may include a first dictionary constructed based on array response vectors corresponding to an angle of arrival and a second dictionary constructed based on array response vectors corresponding to an angle of departure .

The rows of the first dictionary and the second dictionary may be orthogonal.

The communication apparatus according to an exemplary embodiment may include a controller for generating an output pilot beam based on characteristics of a hybrid MIMO transmission structure and a channel, and a MIMO antenna for transmitting the output pilot beam.

Wherein the controller includes a MIMO baseband circuit for generating a baseband pilot beam and a MIMO RF circuit for generating an RF pilot beam, the controller being operable to receive the output pilot beam based on the baseband pilot beam and the RF pilot beam Can be generated.

The MIMO RF circuit may generate a plurality of RF pilot beams and determine a combination of the RF pilot beams from the plurality of RF pilot beams based on the characteristics of the channels.

The number of RF pilot beams included in the combination may correspond to the number of RF chains included in the MIMO RF circuit.

At least one of the baseband pilot beam and the RF pilot beam may be generated such that the columns of the sensing matrix for estimating the millimeter wave channel have a low correlation.

The millimeter wave channel may be a millimeter wave channel sparse representation by a dictionary.

The dictionary may be constructed based on non-uniform quantization.

The dictionary may include a first dictionary constructed based on array response vectors corresponding to an angle of arrival and a second dictionary constructed based on array response vectors corresponding to an angle of departure .

The rows of the first dictionary and the second dictionary may be orthogonal.

1 is a schematic block diagram of a communication system according to one embodiment.
2 is a schematic block diagram of the transmitting apparatus shown in FIG.
FIG. 3 is a diagram for illustrating a scheme of a sparse channel estimation according to an embodiment.
4 illustrates an example of a baseband pilot beam according to one embodiment.
FIG. 5 is an example of an operation for determining the combination of the RF pilot beams of the RF beam former shown in FIG. 2, and FIG. 6 is a view for explaining another example of the operation for determining the combination of the RF pilot beams of the RF beam former shown in FIG. to be.
7 shows an example of an output pilot beam generated according to a combination of RF pilot beams according to an embodiment.
8 is a diagram for explaining the performance of channel estimation of the communication system shown in FIG.
9 is a flowchart for explaining an operation method of the transmitting apparatus shown in FIG.

It is to be understood that the specific structural or functional descriptions of embodiments of the present invention disclosed herein are presented for the purpose of describing embodiments only in accordance with the concepts of the present invention, May be embodied in various forms and are not limited to the embodiments described herein.

Embodiments in accordance with the concepts of the present invention are capable of various modifications and may take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. However, it is not intended to limit the embodiments according to the concepts of the present invention to the specific disclosure forms, but includes changes, equivalents, or alternatives falling within the spirit and scope of the present invention.

The terms first, second, or the like may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example without departing from the scope of the right according to the concept of the present invention, the first element being referred to as the second element, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Expressions that describe the relationship between components, for example, "between" and "immediately" or "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", and the like, are used to specify one or more of the features, numbers, steps, operations, elements, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference symbols in the drawings denote like elements.

1 is a schematic block diagram of a communication system according to one embodiment.

Referring to FIG. 1, a communication system 10 may include a transmission apparatus 100 and a receiving apparatus 200.

The communication system 10 can perform communication in a wireless communication environment. For example, the communication system 10 may be implemented in 3GPP (3 ^rd Generation Partnership Project), Long-Term Evolution (LTE), LTE-Advanced (LTE-A), 3GPP2 and World Interoperability for Microwave Access have.

At this time, the communication system 10 may be a millimeter wave communication system that performs communication through a millimeter wave channel.

That is, the transmitting apparatus 100 and the receiving apparatus 200 can communicate with each other through a millimeter wave channel between the transmitting apparatus 100 and the receiving apparatus 200.

Each of the transmission apparatus 100 and the reception apparatus 200 may be implemented as at least one of a base station, a relay station, and a terminal. The base station may be a mobile station, a fixed station, a Node B, an eNodeB (eNodeB), an access point, or the like.

The terminal may be implemented as a portable electronic device. The portable electronic device may be a laptop computer, a mobile phone, a smart phone, a tablet PC, a mobile internet device (MID), a personal digital assistant (PDA), an enterprise digital assistant A digital still camera, a digital video camera, a portable multimedia player (PMP), a personal navigation device or a portable navigation device (PND), a handheld game console, an e-book, or a smart device. For example, a smart device can be implemented as a smart watch or a smart band.

The transmitting apparatus 100 may generate an output pilot beam based on characteristics of the hybrid MIMO transmission structure and the millimeter wave channel. For example, the output pilot beam may be a directional pilot beam.

The transmitting apparatus 100 may transmit the output pilot beam for estimation of the millimeter wave channel to the receiving apparatus 200. [ The output pilot beam generating operation of the transmitting apparatus 100 will be described in detail with reference to Figs. 2 to 8. Fig.

The receiving apparatus 200 may perform an operation for receiving the output pilot beam and estimating the millimeter wave channel based on the output pilot beam.

FIG. 2 is a schematic block diagram of the transmission apparatus shown in FIG. 1, and FIG. 3 is a diagram for explaining a scheme of a sparse channel estimation according to an embodiment.

1 to 3, the transmission apparatus 100 may include a controller 110 and a MIMO antenna 130. [

The controller 110 may generate a baseband pilot beam, generate an RF pilot beam, and generate an output pilot beam based on the baseband pilot beam and the RF pilot beam. At this time, the output pilot beam may be a directional pilot beam.

The controller 110 may include a MIMO baseband circuit 113 and a MIMO RF circuit 115.

2, the transmission apparatus 100 includes a hybrid (hybrid) system in which a MIMO baseband circuit 113, which is a digital stage of a baseband domain, and a MIMO RF circuit 115, ) MIMO structure.

In the hybrid MIMO architecture of the transmitter 100, the output pilot beam of the transmitter 100 may require a pilot beam design for each of the baseband domain and the RF domain.

The MIMO baseband circuit 113 may generate one or more baseband pilot beams in the baseband domain.

The MIMO RF circuit 115 may generate one or more RF pilot beams of the RF domain. The MIMO RF circuit 115 may include one or more RF chains and an RF beam former 117 for generating one or more RF pilot beams.

The output pilot beam may be generated based on one or more baseband pilot beams and one or more RF pilot beams. For example, the output pilot beam may be generated through linear combination of at least one RF pilot beam and at least one baseband pilot beam via a MIMO antenna 130. [ The MIMO antenna 130 may transmit the output pilot beam to the receiving apparatus 200.

은 MIMO RF 회로(115), 예를 들어 RF 빔포머(117)에서 생성된 파일럿 빔 행렬

과 MIMO 베이스밴드 회로(113)에서 생성된 파일럿 빔 행렬

에 기초하여 수학식 1과 같이 표현될 수 있다.The output pilot beam matrix < RTI ID = 0.0 >

For example, a pilot beam matrix < RTI ID = 0.0 > 117 < / RTI &

And a pilot beam matrix generated in the MIMO baseband circuit 113

1 < / RTI >

은 MIMO 안테나(130)에 포함된 송신 안테나 수이고,

은 파일럿 빔의 수이고,

은 RF 체인의 수를 의미할 수 있다.here,

Is the number of transmit antennas included in the MIMO antenna 130,

Is the number of pilot beams,

May refer to the number of RF chains.

개의 직교한 RF 파일럿 빔이 생성된(또는 고정된) 것으로 가정한다.Hereinafter, baseband pilot beams and RF pilot beam generation according to embodiments of the present invention will be described in detail. However, until the operation of generating the RF pilot beam of the RF beam former 117 is described,

It is assumed that orthogonal RF pilot beams are generated (or fixed).

First, a formulation for sparse channel estimation performed in the communication system 10 will be described.

When the transmitting apparatus 100 transmits the output pilot beam, the receiving signal received at the receiving apparatus 200 can be expressed by Equation (2). At this time, the receiving apparatus 200 may include one or more receiving antennas. Hereinafter, for the sake of convenience of explanation, the operation of the receiving apparatus 100 will not be described in detail.

은 송신 장치(100)와 수신 장치(200) 사이의 무선 채널을 의미하고,

은 수신 장치(200)의 수신 안테나의 수를 의미하고,

는 수신 장치(200)의 잡음(noise)을 의미할 수 있다. 무선 채널은 밀리미터파 채널일 수 있다.Here,

Means a radio channel between the transmitting apparatus 100 and the receiving apparatus 200,

Denotes the number of receiving antennas of the receiving apparatus 200,

May refer to the noise of the receiving apparatus 200. The wireless channel may be a millimeter wave channel.

To utilize the characteristics of the millimeter wave channel, the dictionaries for sparse representation of the millimeter wave channel can be expressed as Equation (3). At this time, the characteristic of the millimeter wave channel may be that the millimeter wave channel has a small number of paths.

와

은 밀리미터파 채널을 스파스 표현시켜 주는 딕셔너리(dictionary)를 의미하고,

은 스파스 채널 행렬

의 벡터화(vectorization)를 의미할 수 있다.procession

Wow

Means a dictionary for sparse representation of a millimeter wave channel,

Is a sparse channel matrix

And the like.

은 채널 행렬

의 벡터화(vectorization)를 의미하고,

은 행렬

의 복소 공액 행렬(complex conjugate matrix)을 의미하고,

은 딕셔너리들로 스파스 표현된 밀리미터파 채널, 즉 스파스 채널 행렬을 의미하고,

은 행렬

의 복소 공액 전치 행렬(complex conjugate and transpose matrix)를 의미하고,

은 행렬

와

의 컬럼(column) 수를 의미할 수 있다.Also,

The channel matrix

(Vectorization)

The matrix

(Complex conjugate matrix) of < RTI ID = 0.0 >

Means a millimeter-wave channel, or sparse channel matrix, sparsely represented by dictionaries,

The matrix

(Complex conjugate and transpose matrix) of < RTI ID = 0.0 >

The matrix

Wow

May mean the number of columns.

와 수신 장치(200)의 수신 안테나의 수

는 수학식 4를 만족할 수 있다.At this time, the number of transmission antennas of the transmission apparatus 100

And the number of receiving antennas of the receiving apparatus 200

(4) can be satisfied.

의 을 추정하는 것임을 알 수 있다.From Equation (3), the sparse channel estimation in the present invention is a millimeter wave channel sparse represented by dictionaries, that is, a sparse channel

Of the total population.

Next, a dictionary configuration according to an embodiment that satisfies Equation (3) will be described. For example, a dictionary may be constructed based on non-uniform quantization.

, 발사각(Angle of Departure(AoD))

, 및 채널 이득(channel gain)에 기초하여 표현될 수 있다. 예를 들어, 밀리미터파 채널이 하나의 스캐터(scatter)로 구성된 경우, 송신 장치(100)에서 바라본 스캐터의 위치 각을 발사각이라 하고, 수신 장치(200)에서 바라본 스캐터의 위치 각을 도래각이라고 할 수 있다.Millimeter wave channels can be composed of a small number of paths. At this time, each path represents the Angle of Arrival (AoA)

, Angle of Departure (AoD)

, And channel gain. ≪ / RTI > For example, when the millimeter wave channel is composed of one scatter, the position angle of the scatter seen from the transmitting apparatus 100 is referred to as a launch angle, and the position angle of the scatter seen from the receiving apparatus 200 comes It can be called angle.

은 AoA에 대응하는 어레이 응답 벡터들(array response vectors)에 기초하여 생성(또는 구성)될 수 있다. 또한,

은 AoD에 대응하는 어레이 응답 벡터들(array response vectors)에 기초하여 생성(또는 구성)될 수 있다. 어레이 응답 벡터들 각각은 기저 벡터(basis vector)일 수 있다.

May be generated (or constructed) based on array response vectors corresponding to AoA. Also,

May be generated (or constructed) based on array response vectors corresponding to AoD. Each of the array response vectors may be a basis vector.

의 각 컬럼은 AoA에 대응하는 어레이 응답 벡터들(array response vectors)로 구성되고,

의 각 컬럼은 AoD에 대응하는 어레이 응답 벡터들(array response vectors)로 구성될 수 있다.E.g,

≪ / RTI > is comprised of array response vectors corresponding to AoA,

May be composed of array response vectors corresponding to AoD.

의 각 컬럼은 발생 가능한 AoA에 대응하는 어레이 응답 벡터들로 구성되고,

의 각 컬럼은 발생 가능한 AoD에 대한 어레이 응답 벡터들로 구성될 수 있다. More specifically,

≪ / RTI > is comprised of array response vectors corresponding to the possible AoA,

May be composed of array response vectors for possible AoD.

와

이 [-1,1]영역에서 균일하게 분포되도록 설정될 수 있다.At this time, the possible AoA / AoD can be set such that the value of the cosine function is uniformly distributed in the dynamic range. E.g,

Wow

Can be set to be uniformly distributed in the [-1, 1] region.

와

은 수학식 5를 만족할 수 있다.Also,

Wow

(5) can be satisfied.

와

는 각각

와

차원의 단위 행렬을 의미할 수 있다.here,

Wow

Respectively

Wow

Dimensional unit matrix.

From Equation (5), it can be seen that the rows of each dictionary are orthogonal. With the orthogonal nature of the rows of each dictionary, the baseband pilot beam and the RF pilot beam can be designed independently in the transmitting apparatus 100, which is a hybrid MIMO transmission structure.

That is, the transmitting apparatus 100 of the hybrid MIMO structure of the present invention can independently generate the baseband pilot beam and the RF pilot beam.

Thus, the sparse channel estimation can be expressed as Equation (6) using Equations (2) and (3).

은 수신 신호 행렬

의 벡터화(vectorization)를 의미하고,

은 수신 장치(200)의 잡음 행렬

의 벡터화(vectorization)를 의미할 수 있다.

Lt; RTI ID = 0.0 >

(Vectorization)

The noise matrix of the receiving apparatus 200

And the like.

는 스파스 채널 행렬

을 추정하기 위한 센싱 행렬을 의미할 수 있다.Also,

Is a sparse channel matrix

May be referred to as a sensing matrix for estimating < RTI ID = 0.0 >

의 구조, 즉 딕셔너리, 베이스밴드 파일럿 빔, 및 RF 파일럿 빔 구조(또는 설계)를 동시에 고려해야 함을 알 수 있다. From Equation (6), the sparse channel estimation aiming at the overhead reduction of millimeter wave channel estimation is a matrix

The base station pilot beam, and the RF pilot beam structure (or design) must be considered at the same time.

의 컬럼(column)들이 직교에 가까운 특성이 만족되도록 생성(또는 설계)될 수 있다. 예를 들어, 각 파일럿 빔은 행렬

의 컬럼(column)들이 낮은 상관성을 갖도록 생성될 수 있다.Each pilot beam, e. G., A baseband pilot beam and an RF pilot beam,

(Or designed) so that the columns of the first and second columns meet near orthogonal properties. For example, each pilot beam may be a matrix

May be generated with low correlation.

Equation (6) can be schematized as shown in FIG. As shown in FIG. 3, since the characteristics of the millimeter wave channel, for example, the millimeter wave channel, have a small angular spread characteristic, a small number of paths can be gathered (or clustered) to form a cluster . For example, a non-zero component (or value) of a sparse channel vector may be gathered (or clustered) to form a cluster. At this time, the above-described characteristics of the millimeter wave channel can be utilized in the RF pilot beam generation.

의 컬럼(column)들이 직교에 가깝도록, 베이스밴드 파일럿 빔은 설계될 필요가 있다. 즉, MIMO 베이스밴드 회로(113)는 행렬

의 컬럼(column)들이 직교에 가깝도록, 베이스밴드 파일럿 빔을 생성할 수 있다.procession

The baseband pilot beam needs to be designed so that the columns of the baseband pilot beam are close to orthogonal. That is, the MIMO baseband circuit 113 outputs the matrix

The baseband pilot beam can be generated such that the columns of the baseband pilot beam are close to orthogonal.

의 대각(diagonal) 성분들은 행렬

의 컬럼들 각각의 파워이고, 행렬

의 비대각(off-diagonal) 성분들은 행렬

의 컬럼들 간의 상호 상관성(cross-correlation) 값들일 수 있다.procession

Diagonal components of the matrix < RTI ID = 0.0 >

The power of each of the columns of matrix < RTI ID =

The off-diagonal components of the matrix < RTI ID = 0.0 >

Correlation values between the columns of the matrix.

의 비대각(off-diagonal) 성분들이 행렬

의 컬럼들(columns) 간의 상관성(또는 상관 관계, correlation)을 나타내기 때문에, 행렬

의 컬럼들 간의 상호 상관성(cross-correlation) 값들이 0에 가깝도록 해야 한다.That is,

The off-diagonal components of the matrix < RTI ID = 0.0 >

(Or correlation) between the columns of the matrix < RTI ID = 0.0 >

The cross-correlation values between the columns of the matrix should be close to zero.

의 컬럼들 간의 상관성을 낮게 하는 설계의 목적 함수는 수학식 7과 같을 수 있다.Assuming that orthogonal RF pilot beams are used,

The objective function of the design that lowers the correlation between the columns of Equation 7 can be expressed by Equation (7).

Under normalization constraints for the final respective beam, the optimization for the generation (or design) of the baseband pilot beam may be as in equation (8).

는 행렬

의 m번째 컬럼을 의미할 수 있다. 수학식 8의 최적화 문제의 해는 수학식 9와 같을 수 있다. here,

The matrix

May refer to the m < th > The solution of the optimization problem in equation (8) can be as in equation (9).

와

는 임의의 유니타리(unitary) 행렬이고,

는 A x B차원의 모든 원소들이 0인 행렬을 의미할 수 있다.here,

Wow

Is an arbitrary unitary matrix,

May refer to a matrix in which all elements of the A x B dimension are zero.

의 컬럼들인 베이스밴드 파일럿 빔들의 관계는 직교해야 하며, 수학적인 의미는 타이트 프레임(tight frame) 구조를 만족하는 베이스밴드 파일럿 빔이 최적임을 뜻할 수 있다.The physical meaning of Equation 9, i.e., optimization,

The relationships of the baseband pilot beams, which are columns of columns, are orthogonal and mathematically meaning that the baseband pilot beam satisfying the tight frame structure is optimal.

4 illustrates an example of a baseband pilot beam according to one embodiment.

와

일 때 수학식 8의

를 나타낸 것이다. 왼쪽은 종래 스파스 채널 추정 방법에서 사용되는 랜덤 형태의 파일럿 빔이고, 오른쪽은 수학식 9가 만족되도록 생성된(또는 설계된) 베이스밴드 파일럿 빔이다.Referring to Figure 4,

Wow

8 "

. The left side is a random type pilot beam used in the conventional sparse channel estimation method and the right side is a baseband pilot beam generated (or designed) so as to satisfy Equation (9).

은 행렬

의 컬럼들 간의 상관성(cross-correlation)을 측정해 보기 위한 것일 수 있다. 행렬

의 대각 성분들은 행렬

의 컬럼들 각각의 파워이고, 행렬

의 비대각 성분들은 행렬

의 컬럼들 간의 상호 상관성(cross-correlation) 값들일 수 있다.procession

The matrix

To measure the cross-correlation between the columns of the column. procession

The diagonal components of < RTI ID =

The power of each of the columns of matrix < RTI ID =

The non-diagonal components of

Correlation values between the columns of the matrix.

As shown in FIG. 4, it can be seen that the values of the non-diagonal components of the baseband pilot beam according to an exemplary embodiment are lower than those of the random pilot beam used in the conventional sparse channel estimation method. That is, the right baseband pilot beams are generated (or designed) as columns having low correlation.

1 to 3, the RF beam former 117 may generate one or more RF pilot beams. For example, the RF pilot beam may be a directional pilot beam.

개의 RF 파일럿 빔들을 생성하고,

개의 RF 파일럿 빔들로부터 수학식 1의 출력 파일럿 빔 생성시 사용되는

개씩의 RF 파일럿 빔의 조합을 결정할 수 있다.In addition, the RF beam former 117 may generate a plurality of RF pilot beams and may determine a combination of RF pilot beams corresponding to the number of RF chains from the plurality of RF pilot beams. For example, the RF beam former 117 may be a directional,

RTI ID = 0.0 > RF < / RTI > pilot beams,

Lt; RTI ID = 0.0 > (1) < / RTI > from the < RTI ID =

It is possible to determine the combination of the RF pilot beams.

FIG. 5 is an example of an operation for determining the combination of the RF pilot beams of the RF beam former shown in FIG. 2, and FIG. 6 is a view for explaining another example of the operation for determining the combination of the RF pilot beams of the RF beam former shown in FIG. to be.

와

의 경우를 가정한다.In FIGS. 5 and 6, for convenience of explanation,

Wow

Is assumed.

Referring to FIGS. 5 and 6, the RF beam former 117 may first generate eight directional orthogonal RF pilot beams. Thereafter, the RF beam former 117 may determine the combination of the two RF pilot beams from the eight RF pilot beams. At this time, the RF beam former 117 may determine the RF pilot beam combination based on the millimeter wave channel characteristics.

As an example, the combination may be sequential. For example, the combinations may be the same as in Fig. 5 in a sequential combination.

As another example, the combination may be random. For example, the combination may be as shown in Figure 6 in a random combination.

One or more RF pilot beams included in the RF pilot beam combination determined by the RF beam former 117 are combined linearly with one or more baseband pilot beams generated by the MIMO baseband circuit 113 via the MIMO antenna 130 Lt; / RTI >

That is, the transmitting apparatus 100 linearly combines at least one baseband pilot beam and at least one RF pilot beam included in the determined RF pilot beam combination to generate an output pilot beam, and outputs the output pilot beam to the MIMO antenna 130 Lt; / RTI >

7 shows an example of an output pilot beam generated according to a combination of RF pilot beams according to an embodiment.

,

및

일 때

구조를 나타낸 것이다. RF 체인이 8개이고 총 송신 안테나 수가 16개이므로, 출력 파일럿 빔은 수학식 1을 통해 두 번 생성될 수 있다.7,

,

And

when

Fig. Since the number of RF chains is eight and the total number of transmit antennas is sixteen, the output pilot beam can be generated twice through Equation (1).

The output pilot beam generated according to the sequential combination of the RF pilot beams has a form in which a 16 x 16 matrix is placed in a block diagonal form. However, the output pilot beam generated according to the random combination of the RF pilot beams is a form in which the values are scattered without being clustered.

은 인접한 컬럼들 간의 상관성이 크게고, 반면에 랜덤 조합으로 생성된 행렬

은 인접한 컬럼들 간의 상관성이 확률적으로 낮을 수 있다.That is, the matrix generated by the sequential combination

The correlation between neighboring columns is large, whereas the matrix generated by random combination

The correlation between adjacent columns may be stochastically low.

가 좋은 성능을 달성함을 예상할 수 있다.As shown in FIG. 3, in a situation where the positions of non-zero components, which are millimeter wave channel characteristics, are adjacent to each other,

Can be expected to achieve good performance.

8 is a diagram for explaining the performance of channel estimation of the communication system shown in FIG.

,

및 채널 추정을 위해 사용된 파일럿 빔의 수를 24로 설정하였다.In the simulation of Fig. 8

,

And the number of pilot beams used for channel estimation was set to 24.

In the simulation, when a random pilot beam used in a conventional sparse channel estimation method is used (CASE1), a baseband pilot beam satisfying Equation (9) and a sequential directional RF pilot beam combination are used (CASE2), a normalized mean square error (MSE) channel estimation performance for a baseband pilot beam satisfying Equation (9) and a random directional RF pilot beam combination (CASE3).

As shown in FIG. 8, it is found that the output pilot beam configured with the combination of the base-band pilot beam and the random-directional RF pilot beam satisfying Equation (9) exhibits the worst performance of the existing random pilot beam achieves the best performance .

By generating the directional output pilot beam based on the characteristics of the hybrid MIMO transmission structure and the millimeter wave channel, the transmitting apparatus 100 can achieve accurate channel estimation performance while reducing the channel estimation burden of the communication system 10. [ In addition, the millimeter wave communication system 10 can improve the sparse channel estimation performance periodically while greatly reducing the channel estimation burden.

That is, the directional output pilot beam generated based on the characteristics of the hybrid MIMO transmission structure and the millimeter wave channel can guarantee a sufficient link budget of the channel estimation.

9 is a flowchart for explaining an operation method of the transmitting apparatus shown in FIG.

Referring to FIG. 9, the transmitting apparatus 100 may generate an output pilot beam based on characteristics of a hybrid MIMO transmission structure and a millimeter wave channel (S910).

The transmitting apparatus 100 may transmit the output pilot beam (S930).

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, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA) , 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 unit 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 , Or may be permanently or temporarily embodied in a transmitted signal wave. 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. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

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)

Generating an output pilot beam based on characteristics of a hybrid MIMO transmission structure and a channel; And
Transmitting the output pilot beam
Lt; / RTI >
Wherein the generating comprises:
Generating a baseband pilot beam;
Generating an RF pilot beam independently of the baseband pilot beam based on characteristics of the channel; And
Generating the output pilot beam based on the baseband pilot beam and the RF pilot beam
Lt; / RTI >
The characteristics of the channel are characteristics of a millimeter wave channel sparse representation by a dictionary,
The dictionary comprising a first dictionary constructed based on array response vectors corresponding to an angle of arrival and a second dictionary constructed based on array response vectors corresponding to an angle of departure,
Wherein the first dictionary and the second dictionary satisfy the following expression,
Wherein each column of the first dictionary is composed of array response vectors corresponding to an arrival angle, each column of the second dictionary is composed of array response vectors corresponding to a launch angle,
The arrival angle and the launch angle are set such that the value of the cosine function is uniformly distributed in the [-1, 1]
Wherein the rows of each of the first dictionary and the second dictionary are orthogonal.
[Mathematical Expression]

Quot; means the first dictionary,

Quot; means the second dictionary,

Denotes the number of transmission antennas,

Is the number of receive antennas.
delete The method according to claim 1,
Wherein the generating the RF pilot beam comprises:
Generating a plurality of RF pilot beams; And
Determining a combination of the RF pilot beams from the plurality of RF pilot beams based on the characteristics of the channel
≪ / RTI >
The method of claim 3,
Wherein the number of RF pilot beams included in the combination corresponds to the number of RF chains.
The method according to claim 1,
Wherein at least one of the baseband pilot beam and the RF pilot beam is generated such that columns of a sensing matrix for estimating the channel have low correlation.
delete The method according to claim 1,
Wherein the dictionary is constructed based on non-uniform quantization.
delete delete A controller for generating an output pilot beam based on characteristics of the hybrid MIMO transmission structure and the channel; And
A MIMO antenna for transmitting the output pilot beam
Lt; / RTI >
The controller comprising:
A MIMO baseband circuit for generating a baseband pilot beam; And
A MIMO RF circuit for independently generating an RF pilot beam on the baseband pilot beam based on the characteristics of the channel;
Lt; / RTI >
The controller generates the output pilot beam based on the baseband pilot beam and the RF pilot beam,
The characteristics of the channel are characteristics of a millimeter wave channel sparse representation by a dictionary,
The dictionary comprising a first dictionary constructed based on array response vectors corresponding to an angle of arrival and a second dictionary constructed based on array response vectors corresponding to an angle of departure,
Wherein the first dictionary and the second dictionary satisfy the following expression,
Wherein each column of the first dictionary is composed of array response vectors corresponding to an arrival angle, each column of the second dictionary is composed of array response vectors corresponding to a launch angle,
The arrival angle and the launch angle are set such that the value of the cosine function is uniformly distributed in the [-1, 1]
Wherein the rows of the first dictionary and the second dictionary are orthogonal.
[Mathematical Expression]

Quot; means the first dictionary,

Quot; means the second dictionary,

Denotes the number of transmission antennas,

Is the number of receive antennas.
delete 11. The method of claim 10,
The MIMO RF circuit includes:
Generating a plurality of RF pilot beams and determining a combination of the RF pilot beams from the plurality of RF pilot beams based on the characteristics of the channels.
13. The method of claim 12,
Wherein the number of RF pilot beams included in the combination corresponds to the number of RF chains included in the MIMO RF circuit.
11. The method of claim 10,
Wherein at least one of the baseband pilot beam and the RF pilot beam is generated such that columns of a sensing matrix for estimating the channel have low correlation.
delete 11. The method of claim 10,
Wherein the dictionary is constructed based on non-uniform quantization.
delete delete

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