ES2712913T3 - Method of generating a codebook and apparatus for generating a code book for multiple-input multiple-output (MIMO) multiple polarization systems - Google Patents

Abstract

A terminal comprising: a codebook storage unit for storing a codebook that includes each of the matrices Wi in which i is a natural number from 1 to 8: ** Formula ** a selector to select a target matrix of Wi matrices; and an information feedback unit for feedback of information associated with the target matrix to a base station.

Description

DESCRIPTION

Procedure of generation of book of codes and apparatus of generation of a book of codes for systems of multiple entrance multiple exit (MIMO) of multiple polarization

Technical field

Aspects of the present invention relate to a multiple input multiple output (MIMO) system and, more particularly, to a book of precoding matrix codes for use in MIMO systems and a method of generating a codebook for its use in such MIMO systems.

Background of the technique

At present, wireless communication technologies are being expanded to provide a variety of multimedia services in wireless communication environments. High-speed data transmission is required to provide high-quality multimedia services in wireless communication systems. Accordingly, various investigations have been conducted to support high-speed data transmission in such wireless communication systems. A recent proposal to achieve high-speed data transmission refers to the use of multiple antennas in both the transmitter and the receiver, known as multiple-input multiple-output (MIMO) systems.

MIMO technology offers significant increases in channel capabilities with limited frequency resources and in data transmission rates using multiple antennas in both the transmitter and the receiver. In such MIMO systems, a number of antennas are used when the dispersion conditions are substantial, and theoretically, MIMO systems provide channel capabilities proportional to the number of antennas. Such MIMO technology can serve as an important component of next-generation mobile communication systems, such as the 3rd Generation Wireless Technologies Project (3GPP), Super 3G (or Long Term Evolution "LTE" 3G), 3GPP2 and the next 4G systems, particularly, for the downlink from a single base station to multiple user equipment.

However, when the MIMO technology is deployed, the physical space and area for antenna installation may be limited. Communication systems using MIMO technology are greatly affected by the separation between antennas. Specifically, as the separation between antennas becomes smaller, a greater correlation between wireless channels can be generated. Particularly, when the antennas have the same polarization, a greater correlation between wireless channels can be generated. The correlation generated between wireless channels reduces the reliability for data communication and also reduces data transmission rates.

Accordingly, various methods of using the antenna polarization address are needed to reduce an installation area of multiple antennas and also to increase channel capabilities. When multiple polarization antennas are used in MIMo systems, the correlation between wireless channels can be reduced. Coding operations, called a precoding, are required to transmit data effectively, through wireless channels, in MIMO systems to maximize performance and system capacity. Pre-coding represents multi-layer beam conformation in which a transmission signal (data) is emitted from each of the antennas according to a data pre-coding rule, ie, appropriate phase weighting (and gain) in such a way that the signal power is maximized at the receiver input and the multipath fading effect is minimized. The weighting can be expressed in terms of a precoding matrix (i.e., a set of beam shaping vectors) and selected from a set of precoding matrices in a codebook.

Currently, there are several types of codebooks designed for the particular cases of single-polarization MIMO schemes in which polarization of antennas is a single polarization. However, no effective code book has been offered in association with cases of multiple polarization MIMO schemes in which polarization of antennas is of multiple polarization. Existing codebooks designed for single-polarization MIMO schemes can not be optimized for multi-polarization MIMO schemes. LG ELECTRONICS AND COL: "CDD-based Precoding for E-UTRA MIMO downlink", 3GPP draft; R1-063345 discloses a terminal or a base station that stores a Walsh-Hadmard matrix.

Accordingly, there is a need for a method and apparatus for generating a code book for a MIMO system with low complexity and excellent performance, even when the polarization of antennas is multiple polarization.

Disclosure of the invention

Technical problem

Aspects of the present invention provide a method and apparatus for generating a code book for a multi-polarization multiple output multiple input (MIMO) system that can generate a precoding matrix using a single polarization precoding matrix even when the polarization of antennas is multiple polarization, and thus obtain an excellent precoding matrix that It is easily generated.

Additional aspects and / or advantages of the invention will be set forth in part in the description that follows and, in part, will be obvious from the description, or may be learned by practicing the invention.

Aspects of the present invention also provide a method and apparatus for generating a code book in a multiple polarization MIMO system that can reconstruct a precoding matrix according to a transmission classification.

Aspects of the present invention also provide a method and apparatus for generating a codebook in a multi-polarization MIMO system that can generate a rotated matrix when the polarization direction of transmission antennas is rotated, which can cope flexible with a change in polarization direction.

Technical solution

The invention is defined by the independent claims. Preferred embodiments of the invention are stipulated in the dependent claims. While various embodiments and / or examples have been disclosed in this description, the subject matter for which protection is sought is strictly limited and only to those embodiments and / or examples included by the scope of the appended claims. Embodiments and / or examples mentioned in the description that do not belong to the scope of the claims are useful for the understanding of the invention. According to one aspect of the present invention, there is provided a method of generating a code book for use in a multiple polarization MIMO, including the procedure: assigning a single polarization precoding matrix to each of diagonal blocks between a plurality of blocks arranged in a diagonal block structure in which a number of diagonal blocks corresponds to a number of polarization directions of transmission antennas; and assign a zero matrix to each of the remaining blocks excluding the diagonal blocks within the diagonal block structure.

According to another aspect of the present invention, the codebook generation method may additionally include: generating a precoding matrix for multiple polarization MIMO by combining the single polarization precoding arrays assigned to the diagonal blocks and the assigned zero matrices to the remaining blocks within the diagonal block structure.

According to another aspect of the present invention, the codebook generation method may additionally include: reconstructing the precoding matrix by selecting, from the precoding matrix, at least one column vector according to a corresponding transmission classification. to a number of data flows to be transmitted.

According to another aspect of the present invention, the codebook generation method may additionally include: generating a precoding matrix rotated using the precoding matrix and a rotated matrix corresponding to a rotated angle of the polarization direction when rotates the polarization direction of transmission antennas.

According to another aspect of the present invention, the codebook generation method may additionally include: adjusting a phase of each of elements included in the reordered matrix using a diagonal matrix.

In accordance with another aspect of the present invention, there is provided a multi-polarization MIMO codebook generating apparatus, the apparatus including: a single polarization precoding matrix allocation unit for assigning a unique precoding matrix. polarization to each of diagonal blocks between a plurality of blocks arranged in a diagonal block structure in which a number of diagonal blocks corresponds to a number of transmission antenna polarization directions; and a zero matrix assignment unit for assigning a zero matrix to each remaining block excluding the diagonal blocks within the block diagonal structure.

In addition to the exemplary embodiments and aspects as described above, additional aspects and embodiments will be apparent by reference to the drawings and by studying the following descriptions. Brief description of the drawings

A better understanding of the present invention will be apparent from the following detailed description of exemplary embodiments and the claims when read in connection with the accompanying drawings, all forming a part of the disclosure of the present invention. While the following written and illustrated disclosure focuses on the disclosure of exemplary embodiments of the invention, it should be clearly understood that it is by way of illustration and example only and that the invention is not limited thereto. The espmtu and scope of the present invention are limited only by the terms of the appended claims. The following represents brief descriptions of the drawings, in which:

Figures 1-3 illustrate multiple polarization transmission / reception antennas in a MIMO system in accordance with exemplary embodiments of the present invention;

Figure 4 is a flow diagram illustrating a method of generating a precoding matrix code book for use in a multiple polarization MIMO system in accordance with an exemplary embodiment of the present invention;

Figure 5 illustrates a precoding matrix for use in a multiple polarization MIMO system according to an example embodiment of the present invention;

Figure 6 illustrates precoding matrices in which a discrete Fourier transform (DFT) matrix of precoding is assigned to diagonal blocks in a multiple polarization MIMO system according to an exemplary embodiment of the present invention; Y

Figure 7 is a block diagram illustrating a codebook generating apparatus for generating a precoding matrix codebook for use in a multi-polarization MIMO system in accordance with an exemplary embodiment of the present invention. invention.

Mode for invention

Reference will now be made in detail to present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, in which like reference numbers refer to similar elements throughout the entire document. The embodiments are described below to explain the present invention with reference to the figures.

Before describing the embodiments of the present invention in detail, examples of current codebooks designed for single-polarization MIMOs including a discrete Fourier transform codebook (DFT) and a reference book are provided in the present document. DFT codes rotated to assist in understanding the construction of the new code book for the particular case of multiple polarization MIMO. For example, a DFT code book that provides a DFT precoding matrix for use in a single polarization MIMO system may be represented as follows:

: Precoding matrix set

: b ^th pre-coding matrix

: m ^th column vector in the matrix

where B is the number of bits needed to indicate one of those

DFT precoding matrices, M is a number of transmit antennas, and it is a DFT codebook that is a set of DFT precoding matrices, and

is the b ^th DFT precoding matrix. The m ^th column vector in the matrix

can be represented as

Specifically, the DFT codebook includes

DFT precoding matrices. Each of the

DFT precoding matrices include M column vectors.

Also, each of the DFT precoding matrices is a matrix of M x M, and

is a vector that has m elements and can be a column vector that has a size of M x 1.

In the DFT codebook,

it can be defined as indicated below:

That is to say,

DFT precoding matrices exist in the DFT code book. Each DFT precoding matrix is a matrix of M x M. Also, each of the DFT precoding matrices of M x M includes M column vectors. Each column vector can be a column vector of M x 1, and elements of the column vector can be determined as in the previous equation 2.

For example, when the polarization of two (2) transmit antennas is single polarization, the DFT precoding matrix can include two arrays given as indicated below,

In contrast to the current DFT code book for single polarization MIMO system, a rotated DFT codebook is a set of DFT precoding matrices rotated for use in a single polarization MIMO system. A rotated DFT code book of this type can be represented as follows:

: so that

A very large rotated DFT pre-coding matrix can be represented as follows:

| Equation 5]

in which

is a DFT precoding matrix in the single polarization MIMO system. The DFT precoding matrix rotated

it is generated by rotating all the elements, included in each of the rows of the DFT precoding matrix, by means of a particular phase.

Also, in a MIMO system, a transmitting antenna located on a transmitter side transmits a data signal, through a wireless channel, to a receiving antenna located on a receiver side. The wireless channel can be referred to as an H-channel matrix. In a multi-polarization MIMO system, the H-channel matrix can be modeled as

In this document, the symbol "

©

"indicates a Hadamard product of matrices and has a calculation rule, as given by:

In the following, the present invention will be described in detail with reference to the accompanying drawings.

Turning now to FIGS. 1-3, various combinations of dual polarization transmit / receive antennas are illustrated for multi-polarization MIMO channels according to example embodiments of the present invention.

Referring to Figure 1, a MIMO system 110 includes two transmit antennas 111 and 112 (2Tx) disposed on one transmitter side, and two receive antennas 113 and 114 (2Rx) disposed on a receiver side. The two transmit antennas 111 and 112 are perpendicular between sn Accordingly, the polarization directions of signals transmitted, through a wireless channel (i.e., H channel matrix), by the transmit antennas 111 and 112 are orthogonal between sl

For 2Tx-2Rx: Pre-coding matrix X can be represented as follows:

The parameter

x

, called depolarization factor, can be considered as a global XPD (cross-polarization discrimination) of the antennas and the channel. The exact value of the depolarization factor can be difficult to quantify since it depends on many factors and will vary from one wireless environment to another. A depolarization factor of this type can cover a wide range of values of values

Similarly, another MIMO system 120, as shown in Figure 2, includes four transmit antennas 121, 122, 123 and 124 (4Tx) disposed on one transmitter side, and two receive antennas 125 and 126 (2Rx) ) arranged on a receiver side. The polarized directions of transmitted signals, through a wireless channel (ie, H-channel matrix), by two transmit antennas 121 and 122 and remaining two transmit antennas 123 and 124 are orthogonal to each other.

For 4Tx-2Rx: Pre-coding matrix X can be represented as follows:

Also, yet another MIMO system 130, as shown in Figure 3, includes four transmit antennas 131, 132, 133 and 134 (4Tx) arranged on one transmitter side, and four transmit antennas 135, 136, 137 and 138 reception (4Rx) arranged on one receiver side.

For 4Tx-4Rx: Pre-coding matrix X can be represented as follows:

,

,

in which

x

it's a real number, and

Referring to Equation 7, the first column and the second column of matrix X correspond to two transmit antennas 121 and 122 (2Tx), and the third column and the fourth column of matrix X correspond to two other antennas 123 and 124 of transmission (2Tx).

Specifically, the H-channel matrix can be modeled as:

H = X © H *.

Also, when four transmit antennas (4Tx) and four receive antennas (4Rx) are arranged in the MIMO system 130, shown in Figure 3, the precoding matrix X can be a 4x4 matrix, as shown in Equation 7. Also, the four transmit antennas 131, 132, 133 and 134 (4Tx) transmit signals in two polarization directions. As a result, the matrix X can be modeled as a precoding matrix that has the two blocks in a diagonal direction.

When a distance between transmission antennas (Tx) and reception antennas (Rx) is small, that is, for example, when the user equipment (UE) is close to the base station (BS), the parameter

x,

called depolarization factor, can be modeled close to zero "0". Conversely, when a distance between transmission antennas (Tx) and reception antennas (Rx) is large, that is, for example, when there are large cells within the wireless networks,

x

it can be modeled close to a "1". Therefore, when

x

changes from "0" to "1", that is, within the range of 0 <X <1, the code book must have excellent performance in both a single polarization MIMO system and a multiple polarization MIMO system.

Figure 4 is a flow chart illustrating a procedure for generating a codebook for use in a multi-polarization MIMO system in accordance with an exemplary embodiment of the present invention. A code book of this type is provided with a set of unitary matrices designed not only for multiple polarization MIMO schemes, but also single polarization MIMO schemes without any significant performance degradation. The codebook for such a multiple polarization MIMO can be constructed in a diagonal block structure, known as a diagonal block multiple polarization codebook. Similarly, a precoding matrix for use in a multi-polarization MIMO in a block diagonal structure of this type can be expressed in terms of M x N, where M indicates a number of transmit antennas on a transmitter side and N indicates a number of data streams in matrix X. The size of a matrix of this type can be determined according to a transmission classification (spatial multiplexing rate) corresponding to at least one of the number of transmit antennas and the number of data flows to be transmitted, through the wireless channels. For example, if the number of transmit antennas (Tx) is four (4) and the transmission classification, that is, the number of data streams is also four (4), then the size of the array can be 4 x 4

A matrix of this type (diagonal block multiple polarization codebook) can be organized or modeled as having a plurality of blocks according to a number of transmission antenna polarization directions within a block diagonal structure. Blocks in a diagonal direction are known as diagonal blocks. In an M x N matrix, the expression "diagonal direction" refers to a direction from an element of a first column and a first row to an element is a Mesima column and Nesima row. For example, when a 4 x 4 matrix is divided into four sets of 2 x 2 matrices, a 2 x 2 matrix that includes elements, included in either the first (1a) or second (2a) column and also included in either the first (1a) or second (2nd) row of the matrix, and another 2 x 2 matrix that includes elements, included in either the third (3a) or fourth (4th) column and also included in or the third (3rd) or fourth (4th) row of the matrix, are characterized as "diagonal blocks."

In this case, when the number of transmission antenna polarization addresses is two (2), the total number of diagonal blocks can be two (2) and the total number of blocks remaining within the diagonal block structure can be two. (two). Similarly, when the number of transmission antenna polarization addresses is three (3), the total number of diagonal blocks can be three (3) and the total number of remaining blocks can be six (6).

Referring to Figure 4, in step S210, a single polarization precoding matrix is assigned to each of diagonal blocks among a plurality of blocks within the diagonal block structure. A single polarization precoding matrix of this type is a precoding matrix designed for single polarization MIMO.

For example, the single polarization precoding matrix assigned to the diagonal blocks in a codebook of this type of multiple diagonal block polarization may include a DFT precoding matrix. or a rotated DFT precoding matrix selected in a matrix codebook designed for single polarization MIMOs, for example, the DFT codebook or the rotated DFT codebook or any other matrix codebook. Any one of the DFT precoding matrix and the rotated DFT precoding matrix can be assigned to diagonal blocks.

In addition, the size of the single polarization precoding matrix can be determined according to the number of transmit antennas (Tx) having the same polarization direction. For example, it is assumed that the total number of transmit antennas (Tx) is eight (8), and the direction of polarization by two transmit antennas (2Tx) is one direction x and the direction of polarization by the remaining six transmit antennas (6Tx) is a direction and. In this case, the direction x is perpendicular to the direction y. Also, the number of polarization directions is two (2), that is, the x and y directions. Accordingly, the pre-coding matrix for multiple polarization MIMO can have two diagonal blocks.

Also, the number of rows of the single polarization precoding matrix that are assigned to a diagonal block can be six (6) and the number of rows of the single polarization precoding matrix that are assigned to the remaining one diagonal block can be two 2). In this case, if the transmission classification is eight (8), more specifically, if the classification of transmission of two antennas that has the address x as the direction of polarization is two (2) and the transmission classification of six antennas that has the address and since the polarization direction is six (6), a single polarization precoding matrix of 2 x 2 can be assigned to any one of two diagonal blocks and a single polarization precoding matrix of 6 x 6 can be assigned to the another of the two diagonal blocks.

In step S220, a zero matrix is assigned to each of the remaining blocks, excluding the diagonal blocks, within the block diagonal structure.

Espe ^d ically, the zero matrix of which all elements are '0' is assigned to blocks that are not the diagonal blocks among the blocks obtained in the diagonal block structure according to the number of directions of polarization of transmission antennas.

In step S230, a pre-coding matrix for multi-polarization MIMO is generated, ie, a multiple-polarization block book of diagonal blocks combining the single polarization pre-coding matrices assigned to the diagonal blocks and the assigned zero matrices to the remaining blocks within the diagonal block structure.

For example, if there are four transmit antennas (4Tx), and two transmit antennas (2Tx) of them have the address x as the direction of polarization and the remaining two transmit antennas (2Tx) have the address and as the address For polarization, the codebook for the multiple polarization MIMO system may include a 4x4 matrix as provided, for example, by:

The two multiple polarization precoding matrices of Equation 8 are only one example of the present invention. Multiple polarization precoding matrices can be generated by randomly combining the two DFT precoding matrices of Equation 3, for example, assigned to the diagonal blocks with the two zero matrices assigned to the remaining blocks within the block diagonal structure. Espe ^d ically, the precoding matrix for the MIMO system of multiple polarizations may be generated organizing precoding matrix in the plurality of blocks according to the number of directions of polarization of transmit antennas, and assigning precoding matrix only polarization to the blocks diagonal between all the blocks. The zero matrix is then assigned to each of the remaining blocks within the diagonal block structure.

For example, when it is assumed that there are four transmit antennas and the number of transmission antenna polarization addresses is two (2), the size of the pre-coding array for multiple polarization MIMOs may be 4 x 4. Also, already that the number of transmission antenna polarization addresses is two (2), the precoding matrix can be organized into a total of four (4) blocks according to the number of polarization directions. The pre-coding matrix for multiple polarization MIMO (multiple diagonal block polarization codebook) is generated next by assigning the single polarization precoding matrix to each of the two (2) diagonal blocks and assigning the zero matrix to each one of the two (2) remaining blocks that are not the two (2) diagonal blocks within the diagonal block structure.

In step S240, the precoding matrix (diagonal block multiple polarization codebook) is then reconstructed by selecting, from the same precoding matrix, at least one column vector according to a transmission classification corresponding to a number of data flows to be transmitted, through the wireless channel.

For example, it can be assumed that if four transmit antennas have a multiple polarization, a precoding matrix of 4 x 4 is generated. The precoding matrix of 4 x 4 is given by:

Referring to Equation 9, when the transmission classification is two (2), the precoding matrix (multiple diagonal block polarization codebook) can be reconstructed by selecting two column vectors from the four column vectors included in the matrix of precoding. Specifically, the precoding matrix of Equation 9 can be reconstructed to generate six precoding matrices that have a size of 4 x 2, as given by:

When the number of transmit antennas is M and the transmission classification is r, a precoding matrix of M x M can be generated. Also, a precoding matrix of M xr can be generated by selecting column vectors according to the transmission classification. and reconstructing the precoding matrix. Specifically, according to the present invention, unnecessary column vectors can be eliminated from the precoding matrix by reconstructing the precoding matrix according to the transmission classification, and therefore a codebook can be generated efficiently.

In step S250, when the transmission antenna polarization direction is rotated, a rotated precoding matrix is generated using the precoding matrix and a rotated matrix. The rotated matrix may correspond to a rotated angle of polarization direction of transmission antennas (Tx).

The network structure of transmission antennas can be incorporated in different ways. For example, in the multi-polarization MIMO system, the transmit antennas corresponding to a polarization direction can be installed vertically with respect to a reference plane and the transmit antennas corresponding to another polarization direction can be installed horizontally with respect to to the reference plane. Also, the transmit antennas corresponding to a polarization direction can be installed in a 45 degree direction relative to the reference plane and the transmit antennas corresponding to the other polarization direction can be installed in a -45 degree direction. with respect to the reference plane.

^Espe d ^{cally, when the polarization direction of transmission antennas is rotated through a} particular ^angle with respect to the reference plane, a data stream must be modified by beamforming using precoding matrix rotated. The rotated precoding matrix can be generated by rotating the ^precoding matrix ^{. Espe} d ^{ically, the precoding matrix may be generated} by ^{multiplying rotated} precoding ^matrix and the rotated matrix.

For example, when it is assumed that two respective transmit antennas are installed between four transmit antennas in a 45 degree direction and in a direction of -45 degrees with respect to the reference plane, the rotated matrix may be represented as follows. :

The rotated matrix

can be multiplied by a random complex value. The resulting structure when the rotated matrix is multiplied

by the random scalar value belongs to the scope of the present invention.

When the precoding matrix is named as

the precoding matrix rotated

that is generated by rotating the precoding matrix

It can be represented as follows:

Referring to Equation 12, the matrix rotated

it can be determined to correspond to the rotated angle of polarization direction of transmission antennas. In accordance with the present invention, even when various types of networks are provided, such as transmission antennas with a rotated polarization direction, the rotated precoding matrix can be easily generated using the rotated matrix.

In step S250, a reordered matrix is obtained by rearranging column vectors that are included in the precoding matrix, and the reordered matrix and the rotated matrix are used to generate a rotated precoding matrix.

For example, it is assumed that when two respective transmit antennas are installed between four transmit antennas in a 45 degree direction and in a direction of -45 degrees with respect to the reference plane, the precoding matrix

is generated. In this case, the matrix rotated

is the same as Equation 11. The precoding matrix

It is represented as indicated below:

When column vectors included in the precoding matrix

of Equation 13 are reordered, the rearranged matrix

It can be represented as indicated below

Using the reordered matrix

and the rotated matrix

of Equation 11, the precoding matrix rotated

can be generated and a data stream can be modified by beam shaping using the rotated precoding matrix

represented as indicated below:

Referring to Equation 15, it can be seen that when two respective transmit antennas are installed between four transmit antennas in a 45 degree direction and in a direction of -45 degrees with respect to the reference plane, the precoding matrix rotated

which corresponds to the precoding matrix

of Equation 13 can be generated as Equation 15.

In step S260, one phase of each element included in the reordered matrix is adjusted. The phase of each of the elements included in the reordered matrix can be adjusted using a diagonal matrix. In this case, the diagonal matrix includes diagonal elements. Also, the phase of each of the diagonal elements may be the same or different from each other. The amplitude of each diagonal element is set to '1'. The amplitude of each of the remaining elements, excluding the diagonal elements, is set to '0'.

The diagonal matrix is associated with a scheme of modulating data symbols, instead of increasing channel capabilities of the MIMO system and the like. For example, when the data symbol is modulated using quaternary phase shift modulation (QPSK), the diagonal matrix can only change the phase of the data symbol, but may not affect the channel capabilities of the MIMO system.

In this case, it is assumed that the precoding matrix

and the reordered matrix

w _reorder.BD

are provided by:

In this case, the phase of each element included in the reordered matrix

W _{rT reorder, BD}

can be adjusted as Equation 17 below, and data symbols can be modified by beam shaping using

W reorder, £ D

Equation 17 is given by:

Aspects of the present invention can be recorded on a computer readable medium that includes program instructions for implementing various operations incorporated by a computer. The medium may also include, alone or in combination with the program instructions, data files, data structures and the like. Examples of computer readable medium include magnetic means such as hard disks, floppy disks and magnetic tape; optical media such as CD ROM and DVD discs; magneto-optical means such as optical discs; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), Random Access Memory (RAM), flash memory and the like. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher-level code that can be executed by the computer using an interpreter. The described hardware devices can be configured to act as one or more software modules to perform the operations of the above-described embodiments of the present invention.

Figure 5 illustrates a precoding matrix for use in a multiple polarization MIMO system according to an example embodiment of the present invention.

Referring to Figure 5, when the number of transmit antennas is four (4) and the number of transmission antenna polarization directions is two (2), U indicates a precoding matrix for the multiple polarization MIMO system. . Matrices such as a matrix 310 'A' and a matrix 320 'B', as shown in Figure 5, indicate a single polarization precoding matrix, i.e., a precoding matrix selected from a codebook of matrix designed for single-polarization MIMO, for example, DFT code book or rotated DFT codebook or any other matrix codebook, and two matrices 330 and 340 'O' indicate zero matrices.

Since the number of polarization directions of transmit antennas is two (2), there are two diagonal blocks and two remaining blocks. The matrix 310 'A' and the matrix 320 'B', that is, single-polarization pre-coding matrices, are assigned to the diagonal blocks respectively. The matrices 330 and 340 'O', that is, zero matrices, are assigned to the remaining blocks respectively.

The size of the matrix 310 'A' and the matrix 320 'B' can be determined according to the number of transmission antennas having the same polarization direction.

For example, when the transmission antenna polarization directions are a direction x and a direction y, the number of transmission antenna polarization directions may be two (2). Also, it can be assumed that when a total number of transmit antennas is four (4), the direction of polarization of two transmit antennas is the x direction and the polarization direction of the remaining two transmit antennas is the y direction. In this case, the matrix 310 'A' can be a single polarization precoding matrix corresponding to the polarization direction of the x direction. Since the number of transmission antennas having a polarization direction in the x direction is two (2), the number of rows of the matrix 310 'A' can be two (2). Also, the number of rows of the matrix 320 'B' can be two (2).

When the transmission classification for the address x is two (2), the number of rows of the matrix 310 'A' can be two (2). Also, when the transmission classification for the address y is two (2), the number of rows of the matrix 320 'B' can be two (2).

Figure 6 illustrates single polarization precoding arrays, such as DFT precoding arrays assigned to diagonal blocks in a multiple polarization MIMO system according to an exemplary embodiment of the present invention.

Referring to Figure 6,

Y

W _SD.2

they are precoding matrices when the number of transmit antennas is four (4), the number of polarization directions of transmit antennas is two (2), and the number of transmit antennas having the same polarization direction is two ( two).

DFT precoding arrays that are assigned to diagonal blocks of precoding matrices

Y

they can be represented as indicated below:

An example of reordered matrices

Y

that are generated by rearranging column vectors included in the precoding matrices

Y

they can be represented as indicated below:

Reordered matrices can be multiplied by a diagonal matrix. In this case, diagonal elements of the diagonal matrix are complex numbers that have the size of 1, and remaining elements are 0. The diagonal matrix does not affect channel capabilities or beam shaping performance, and is associated with a modulation scheme of data symbols.

For example, the phase of each element included in the reordered matrices using random diagonal matrices can be adjusted as shown in Equation 20. In this case, diagonal elements of a diagonal matrix

they can be random complex numbers that have the magnitude of 1.

[Equation 20]

Also, a rotated precoding matrix

can be generated from

which is generated using the reordered matrix

and the diagonal matrix

D.

More specifically, the precoding matrix rotated

can be generated through a mathematical transformation of precoding matrices

Y

In this case, when a reordered matrix is generated from the precoding matrix, and

is generated by multiplying the reordered matrix and the diagonal matrix, the precoding matrix rotated

can be given by:

(Equation 21]

Using Equation 21, the precoding matrix rotated

with respect to

W _{C, i}

included in Equation 20 can be represented as follows:

[Equation 22]

Referring to Equation 22, when transmitting antennas are installed which correspond to a polarization direction in a direction of 45 degrees with respect to the reference plane and transmission antennas are installed which correspond to another direction of polarization in a direction of - 45 degrees with respect to the plane of reference, four (4) precoded precoding matrices can be generated using the rotated matrix. In this case, although four precoding matrices rotated in Equation 22 are expressed, it will be apparent to those skilled in the art that various types of rotated precoding matrices can be generated using the technical espmtus of the present invention.

Also, the precoding matrix rotated

It can be represented as follows:

When the rotated precoding matrix is calculated

using Equation 22 and Equation 23, it can be represented as follows:

Accordingly, various types of communication apparatuses that transmit / receive data according to a multiple space division access scheme (SDMA) can perform communication using at least one of the precoding matrices disclosed in Equation 24. SDMA indicates a technology that enables a base station to transmit (or receive) signal (that is, at least one data stream) to (or from) multiple users in the same bandwidth and moment simultaneously, through multiple antennas to maximize a rate of data transmission and total capacity. In the present document, the precoding matrices disclosed in Equation 24 are based on when a transmission classification is 4, but it is possible to generate precoding matrices corresponding to various types of transmission classifications by selecting column vectors from the precoding matrices unveiled in Equation 24.

Also, the base station (BS) and terminals can store the matrix codebook of Equation 24 on a computer readable recording medium, etc. When the base station (BS) transmits a pilot signal, each of the terminals can select any of the arrays stored in response to the pilot signal. In this case, each of the terminals can select any matrix based on the state of a wireless channel formed between each of the terminals and the base station, and can also select any matrix based on a data transmission rate. reachable. Also, each of the terminals can select any color vector from the column vectors included in the selected matrix.

Also, the terminals may feed back to the base station information associated with the selected array, or information associated with the selected column vector. The information associated with the selected matrix can be index information of the selected matrix and the information associated with the selected column vector can be index information of the selected column vector.

In this case, the base station (BS) may select any of the matrices disclosed in Equation 24, as a precoding matrix, based on the information fed from the terminals. In particular, the base station can select the precoding matrix according to a scheme of Unit Rate Control per User (PU2RC). The base station (BS) can perform precoding (beam shaping) in a data stream to be transmitted, via transmission antennas, using the selected precoding matrix. Specifically, a terminal according to an aspect of the present invention can include a signal receiver for receiving a pilot signal transmitted from a base station; including a codebook storage unit for storing a codebook at least one

w,

where i is a natural number from 1 to 8 ,:

a selector to select a target array of the at least one stored

in response to the pilot signal; and an information feedback unit for feedback information associated with the target matrix to the base station.

In this case, the selector can select the target matrix of the stored code book that includes at least one

w,

based on the state of a wireless channel formed between the terminal and the base station. Also, the selector can select the target array of the stored codebook that includes at least one

based on an achievable data transmission rate. And the selector selects the target array of the stored codebook that includes at least one

w,

in response to the pilot signal, and selects at least one column vector of column vectors included in the selected target matrix. In this case, the information feedback unit may feed back to the base station information associated with the selected target matrix and information associated with the at least one selected column vector.

Also, a base station according to one aspect of the present invention may include a codebook storage unit for storing a codebook that includes at least one

where i is a natural number from 1 to 8 ,:

an information receiver for receiving information associated with a matrix selected by a stored codebook terminal that includes at least one

W s:

a matrix selector for selecting a precoding matrix based on information associated with the selected matrix; and a precoder for performing precoding in a data stream to be transmitted using the selected precoding matrix.

In this case, the information receiver may receive information associated with arrays corresponding to a plurality of terminals, in which the arrays are selected by the plurality of terminals respectively, the matrix selector may select the precoding matrix based on information. associated with the matrices corresponding to the plurality of terminals.

Turning now to Figure 7, a block diagram of a codebook generation apparatus of a precoding matrix codebook for use in a multi-polarization MIMO system according to an embodiment of the invention is illustrated. example of the present invention. Referring to Figure 7, the codebook generation apparatus includes a single polarization precoding matrix assignment unit 510, a zero matrix allocation unit 520, a precoding matrix generation unit 530, a unit 540 of precoding matrix reconstruction, a rotated precoding matrix generation unit 550 and a phase adjustment unit 560.

The single polarization precoding matrix allocation unit 510 allocates a single polarization precoding matrix to each of diagonal blocks among a plurality of blocks within a block diagonal structure. The blocks are organized according to a number of polarization directions of transmission antennas.

The zero matrix assignment unit 520 allocates a zero matrix to remaining blocks excluding the diagonal blocks within the block diagonal structure.

The precoding matrix generation unit 530 generates a pre-coding matrix for multiple polarization MIMOs (ie, a multi-polarization block book of diagonal blocks) by combining the single polarization precoding arrays assigned to the diagonal blocks and the matrices zero assigned to the remaining blocks within the diagonal block structure.

The precoding matrix reconstruction unit 540 reconstructs the precoding matrix selecting, from the precoding matrix, at least one column vector according to a transmission classification corresponding to a number of data streams to be transmitted.

The rotated precoding matrix generation unit 550 generates a precoding matrix rotated using the precoding matrix and a rotated matrix corresponding to a rotated angle of the polarization direction when the polarization direction of transmit antennas is rotated.

The rotated precoding matrix generation unit 550 can generate a reordered matrix by rearranging column vectors that are included in the precoding matrix, and generates the precoded rotation matrix using the reordered matrix and the rotated matrix.

The phase adjustment unit 560 adjusts a phase of each of the elements included in the reordered matrix using a diagonal matrix.

Descriptions not made in relation to the apparatus of Figure 7 will be the same as the descriptions made with reference to Figures 1 to 6, and therefore are omitted.

Arrays included in a precoding matrix (multiple diagonal block polarization codebook) that are generated according to one aspect of the present invention will be stored in various types of communication devices and used. For example, a communication apparatus can transmit and receive data in a multiple-space communication (SDMA) communication system using a matrix that is generated in accordance with an aspect of the present invention. The communication apparatus may include various types of devices for the SDMA communication system, such as a base station, a repeater, a terminal and the like.

Specifically, a communication apparatus according to one aspect of the present invention can store a precoding matrix (diagonal block multiple polarization codebook) that is generated by assigning a single polarization precoding matrix to diagonal blocks between a plurality of blocks within a diagonal structure of blocks that are divided or organized according to the number of polarization directions of transmission antennas, and assign a zero matrix to remaining blocks excluding the diagonal blocks within the diagonal block structure.

According to one aspect of the present invention, the precoding matrix (diagonal block multiple polarization codebook) can be generated by combining the single polarization precoding arrays assigned in diagonal blocks and the assigned zero matrices in remaining blocks within the Diagonal structure of blocks.

Also, a communication apparatus according to one aspect of the present invention can store a matrix that is reconstructed by selecting, from the precoding matrix, at least one column vector according to a transmission classification corresponding to a number of streams of data to be transmitted.

Also, a communication apparatus according to one aspect of the present invention can store a rotated precoding matrix that is generated using the precoding matrix and a rotated matrix corresponding to a rotated angle of the polarization direction when the address is rotated. polarization of transmission antennas.

Also, a communication apparatus according to an exemplary embodiment of the present invention can generate a reordered matrix by rearranging column vectors that are included in the precoding matrix, and store a matrix that is generated using the reordered matrix and the rotated matrix .

When the communication apparatus is a base station (BS) used to support multiple user equipment (UE) in a wireless network, such as 3GPP, Super 3G (Long Term Evolution "LTE" 3G), 3GPP2 and upcoming 4G systems, the base station (BS) can transmit a transmission signal that modifies a data stream using beam matrices included in the base station (BS). Specifically, the base station (BS) may include a codebook storage unit that stores a matrix codebook according to the present invention and a beamformer that modifies data flows using the stored arrays by beamforming. .

Conversely, when the communication apparatus is a terminal, the terminal can generate feedback data using selected arrays of a codebook stored in the terminal. The feedback data is used when the base station (BS) performs beam shaping in which multiple data streams are output from transmit antennas according to selected arrays of a codebook stored in the terminal. Specifically, the terminal may include a codebook storage unit that stores a matrix codebook according to the present invention and a feedback data generation unit that generates feedback data corresponding to a wireless channel of the device. base station using the stored matrices.

In accordance with aspects of the present invention, a method and apparatus for generating a code book for a multiple polarization MIMO system that can generate a precoding matrix is provided. using a single polarization precoding matrix even when the antenna polarization is multiple polarization, and thus generate an excellent precoding matrix that is easily generated. A code book of this type can be shared by one transmitter end and one receiver end.

Also, according to aspects of the present invention, there is provided a method and apparatus for generating a code book in a multi-polarization MIMO system that can reconstruct a precoding matrix according to a transmission classification and thus can generate more effectively a code book.

Also, in accordance with aspects of the present invention, there is provided a method and apparatus for generating a codebook in a multiple polarization MIMO system that can generate a rotated matrix when the polarization direction of transmit antennas is rotated, and in this way it can cope more flexibly with a change in the direction of polarization.

As described from the above, a code book with low complexity and excellent performance and robustness can be advantageously obtained for use in multiple polarization MIMO schemes. Such a code book design can also be used for single polarization MIMO schemes without any significant performance degradation.

Various components of the codebook generating apparatus, as shown in Figure 7, such as, the single polarization precoding matrix allocation unit 510, the zero matrix allocation unit 520, the generation unit 530 precoding matrix, precoding matrix reconstruction unit 540, rotated precoding matrix generation unit 550 and phase adjusting unit 560 can be integrated into a single control unit, such as a baseband processor or controller located on a transmitter side, eg, a base station, or alternatively, can be implemented in software or hardware, such as, for example, a programmable gate array field (FPGA) and a dedicated application integrated circuit (ASIC) ). As such, it is conceived that the methods described herein are broadly interpreted as being performed in an equivalent manner by software, hardware or a combination thereof. As discussed above, software modules can be written, through a variety of software languages, including C, C ++, Java, Visual Basic and many others. These software modules may include data and instructions that may also be stored in one or more machine-readable storage media, such as dynamic or static random access memories (DRAM or SRAM), erasable and programmable read-only memories (EPROM), electrically erasable and programmable read-only memories (EEPROM) and flash memories; magnetic discs such as fixed, flexible and removable discs; other magnetic media including tape; and optical media such as compact discs (CD) or digital video discs (DVD). Instructions for routines or software modules can also be loaded or transported on wireless cards or any computer device in the wireless network in one of many different ways. For example, code segments that include instructions stored on floppy disks, CD or DVD media, a hard drive, or transported through a Network Interface Card, modem, or other interface device can be loaded into the system and run as corresponding routines or software modules. In the charging or transporting procedure, data signals that are incorporated as carrier waves (transmitted through telephone line, network lines, wireless links, cables and the like) can communicate the code segments, including instructions, to the data node. network or element. Such carrier waves can be in the form of electrical, optical, acoustic, electromagnetic signals or other types of signals.

In addition, the codebook generation procedure as shown in Figure 4 can be recorded on a computer readable medium that includes program instructions for implementing various operations incorporated by a computer. The medium may also include, alone or in combination with the program instructions, data files, data structures and the like. Examples of computer readable media include magnetic media such as hard drives, floppy disks and magnetic tape; optical media such as CD ROM and DVD discs; magneto-optical means such as optical discs; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. The medium may also be a transmission medium such as optical or metal lines, wavelets and the like, including a carrier wave that transmits signals specifying the program instructions, data structures and the like. Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher-level code that can be executed by the computer using an interpreter. The described hardware devices can be configured to act as one or more software modules to perform the operations of the above-described embodiments of the present invention.

While illustrating and describing what are considered to be exemplary embodiments of the present invention, it will be understood by those skilled in the art that various changes and modifications can be made to the described embodiments as long as they fall within the scope of the claims. For example, the antenna arrangement, shown in Figures 1-3, usually includes a transmitter side having transmission antennas X ⁱ ... X ^m and a receiver side provided with N receiving antennas Y ⁱ ... Y ⁿ to communicate, through a wireless channel (channel matrix H). For mobile communication systems, a base station (BS), known as "Node-B" as specified in accordance with 3GPP, 3GPP2 and 4G specifications, is used at the end of transmitter to transmit data, through wireless channels. User equipment (UE), usually mobile stations (MS), are used at the receiver end to receive data, through the wireless channels. Such user equipment (UE) can be, for example, mobile telephones (microtelephones), personal digital assistants (PDA) or other devices such as wireless cards in portable computers or computers with wireless internet connectivity, WiFi and WiMAX devices, etc. The wireless network may be that of any of the wireless communication technologies, including, but not limited to, GSM (Global System for Mobile Communications), CDMA (Multiple Access by Code Division), WLL (Wireless Local Loop), WAN (Network of Extended Area), WiFi and WiMAX (Global Interoperability for Microwave Access based on IEEE 802.16 standards), and is applicable with many existing and emerging wireless standards such as IEEE 802.11 (for wireless local area networks), IEEE 802.16 (for networks of metropolitan wireless area) and IEEE 802.02 (for wireless broadband wireless access). The base station (BS) can also be an access point (AP) of IEEE 802.11 and the UE can also be any client station. As an alternative, the base station can also be implemented with a GERAN (GSM / EDGE radio access technology) in a UTRAN (UMTS Land Radio Access Network) using a broadband code division multiple access technology ( WCDMA). However, the invention is not limited to these radioelectric access technologies, but can also be applied to the following radioelectric access technologies: GSM (Global System for Mobile Communications), GPRS (General Radio Packet Service), E-GPRS (EDGE GPRS), CDMA2000 (CDMA, Multiple Access by Division of Code), US-TDMA (Multiple Access by Division in the Time of United States) and IS-95. Accordingly, it is therefore conceived that the present invention is not limited to the various exemplary embodiments disclosed, but that the present invention includes all embodiments that pertain to the scope of the appended claims.

Claims (12)

1. A terminal comprising: a code book storage unit for storing a code book that includes each of the matrices Wi in which i is a natural number from 1 to 8:

a selector to select an objective matrix of the Wi matrices; Y an information feedback unit for feedback information associated with the target matrix to a base station. 2. The terminal according to claim 1, wherein the selector selects the target array of the stored codebook that includes the Wi arrays based on the state of a wireless channel formed between the terminal and the base station. The terminal according to claim 1, wherein the selector selects the target array of the stored codebook that includes the arrays Wi based on an achievable data rate of transmission. 4. The terminal according to claim 1, wherein Wi is a rotated precoding matrix. 5. The terminal according to claim 1, wherein the selector selects the target array of the stored codebook that includes the Wi matrices, and selects at least one vector of vector column from column included in the selected target matrix, and the information feedback unit feeds back to the base station information associated with the selected target matrix and information associated with the at least one selected column vector. 6. The terminal according to claim 5, wherein the information feedback unit feeds back to the base station the index information of the selected target matrix and index information of the at least one selected column vector. 7. A procedure for operating a terminal, comprising: receive a pilot signal transmitted from a base station store a code book that includes each of the matrices Wi in which i is a natural number from 1 to 8:

select an objective matrix of the stored code book that includes the Wi matrices in response to the pilot signal; Y feedback information associated with the target matrix to the base station. 8. A base station comprising: a code book storage unit for storing a code book that includes each of the matrices Wi in which i is a natural number from 1 to 8:

an information receiver for receiving information associated with a matrix selected by a terminal of the stored codebook that includes the Wi matrices; a matrix selector for selecting a precoding matrix based on information associated with the selected matrix; Y a precoder for performing precoding in a data stream to be transmitted using the selected precoding matrix. 9. The base station according to claim 8, wherein: the information receiver receives information associated with matrices corresponding to a plurality of terminals, in which the matrices are selected by the plurality of terminals respectively, and the matrix selector selects the precoding matrix based on information associated with the matrices corresponding to the plurality of terminals. 10. The base station according to claim 9, wherein the matrix selector selects the precoding matrix according to a unit rate control scheme per user (PU2RC). 11. An operation procedure of a base station, comprising: store a code book that includes each of the matrices Wi in which i is a natural number from 1 to 8:

select a precoding matrix of the stored code book that includes the Wi matrices; and performing precoding in a data stream to be transmitted using the selected precoding matrix. 12. A communication system that includes: a terminal configured to store a code book that includes each of the matrices Wi in which i is a natural number from 1 to 8:

and configured to select a target array of the stored codebook that includes the Wi arrays in response to a pilot signal, and to feedback information associated with the target array; Y a base station configured to store each of the matrices Wk in which k is a natural number from 1 to 8:

and configured to receive information associated with the target matrix selected by the terminal, and to select a precoding matrix of the stored codebook including the Wk matrices, based on the information associated with the selected target matrix, and to perform precoding in a data stream to be transmitted using the selected precoding matrix.