CN101867461B

CN101867461B - Channel information acquisition method and device and codebook construction method

Info

Publication number: CN101867461B
Application number: CN201010174928.3A
Authority: CN
Inventors: 陈艺戬; 李儒岳; 李书鹏; 徐俊
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2010-04-30
Filing date: 2010-04-30
Publication date: 2015-06-03
Anticipated expiration: 2030-04-30
Also published as: WO2011134246A1; CN101867461A

Abstract

The invention discloses a channel information acquisition method and a device and a codebook construction method, which solve the technical defect that in the existing technology, a terminal can not flexibly send channel information according to the specific needs. The acquisition method comprises the following steps that: the terminal sends information R1 information PMI1 and information PMI2 of the current channel to a base station, wherein information R1 indicates rank (upsilon) of the current channel, and upsilon is a positive integer being less than or equal to 8; the base station finds a matrix W1 being 8*upsilon according to the information R1 and the information PMI1, and finds a corresponding matrix W2 according to information PMI2 or the information R1 and the information PMI2; and the base station adjusts the phase of each element in the matrix W1 according to the function F (W1, W2) to acquire an adjustable matrix which is used to be as channel information of a sonband. Compared with the prior art, the channel information feedback technology provided by the technical scheme of the invention can solve the feedback problem when in each Rank.

Description

Channel information acquisition method and device and codebook construction method

Technical Field

The present invention relates to the field of communications, and in particular, to a method and an apparatus for acquiring channel information, and a method for constructing a codebook.

Background

In a wireless communication system, a transmitting end and a receiving end adopt a spatial multiplexing mode to use a plurality of antennas to obtain higher speed. Compared with a general spatial multiplexing method, an enhanced technology is that a receiving end feeds back channel information to a sending end, and the sending end uses a transmitting pre-coding technology according to the obtained channel information, so that the transmission performance can be greatly improved. For single-user multiple-input multiple-output (SU-MIMO, where MIMO denotes Multi-input Multi-output, multiple-input multiple-output), precoding is performed directly using channel feature vector information; for multi-user MIMO (MU-MIMO), relatively accurate channel information is required.

In the 3GPP Long Term Evolution (LTE) plan, feedback of channel information mainly uses a simpler feedback method of a single codebook, and performance of the MIMO transmission precoding technology depends on accuracy of codebook feedback.

The basic principle of codebook-based quantization feedback of channel information is briefly described as follows:

assuming that the limited feedback channel capacity is bps/Hz, the number of available codewords is N-2^BAnd (4) respectively. The characteristic vector space of the channel matrix is quantized to form a codebook spaceThe transmitting end and the receiving end jointly store or generate the codebook in real time(the transmitting end and the receiving end are the same). For each channel, H is realized, and the receiving end follows the codebook space according to a certain criterionSelects a code word which is matched with the channel to realize H bestAnd combining the code wordThe sequence number i (codeword sequence number) of (a) is fed back to the transmitting end. Here, the codeword number is referred to as a Precoding Matrix Indicator (Precoding Matrix Indicator) in the codebookAbbreviated PMI). The transmitting end finds out the corresponding pre-coding code word according to the sequence number iSo that the corresponding channel information is also obtained,the feature vector information of the channel is represented.

Codebook space in generalThe method can be further divided into a plurality of codebooks corresponding to the ranks, and each Rank is corresponding to a plurality of code words to quantize a precoding matrix formed by the channel feature vectors in the Rank. Since the number of Rank and non-zero eigenvector of a channel is equal, in general, a codeword has N columns when Rank is N. Therefore, the codebook spaceThe codebook can be divided into a plurality of sub-codebooks according to the Rank, as shown in table 1.

TABLE 1 codebook divided into multiple sub-codebooks by Rank schematic

When Rank is greater than 1, the code words required to be stored are all in a matrix form, wherein a codebook in an LTE protocol is the codebook quantization feedback method, and an LTE downlink 4 transmitting antenna codebook is shown in a table 2, and actually a precoding codebook and a channel information quantization codebook in LTE have the same meaning. In the following, for the sake of uniformity, a vector may also be considered as a matrix with dimension 1.

TABLE 2 LTE Downlink 4 transmit antenna codebook schematic

Codebook u_nTotal number of layers upsilon

Indexing

1 2 3 4

0 u₀＝[1 -1 -1 -1]^T

1 u₁＝[1 -j 1 j]^T

2 u₂＝[1 1 -1 1]^T

3 u₃＝[1 j 1 -j]^T

4

5

6

7

8 u₈＝[1 -1 1 1]^T

9 u₉＝[1 -j -1 -j]^T

10 u₁₀＝[1 1 1 -1]^T

11 u₁₁＝[1 j -1 j]^T

12 u₁₂＝[1 -1 -1 1]^T

13 u₁₃＝[1 -1 1 -1]^T

14 u₁₄＝[1 1 -1 -1]^T

15 u₁₅＝[1 1 1 1]^T

WhereinI is a unit array, and I is a unit array,a representation matrix W_kThe jth column vector of (1).A representation matrix W_kJ (d) of₁，j₂，...，j_nA matrix of columns is formed by the rows,represents u_nThe conjugate transpose matrix of (a); wherein n represents a serial number and takes a value of 0-15.

With the development of communication technology, there is a higher demand for spectral efficiency in long term evolution Advanced (LTE-Advanced), and therefore, 8 antennas are also increased, for which 8 transmit antenna codebook feedbacks need to be designed for quantization feedback of channel information. 8 antennas, one application form is dual-polarized antennas (other application forms also have other configurations of transmitting antennas), so that a codebook suitable for dual-polarized channels needs to be designed.

In the LTE standard, the minimum feedback unit of channel information is a sub-band (Subband), one sub-band is composed of several Resource Blocks (RBs), and each RB is composed of multiple Resource Elements (REs). RE is the minimum unit of time-frequency resources in LTE, and the LTE-A continues to use the resource representation method of LTE. A few subbands may be referred to as Multi-subbands (Multi-subbands) and a large number of subbands may be referred to as wide subbands (widebands).

Some contents related to channel information feedback in LTE are described below, and the contents of interest in the present invention are Rank Indicator (RI) information and PMI information of a channel, and Channel Quality Indication (CQI) information may be fed back together with a PMI.

The channel state information feedback comprises: channel quality indication information (CQI for short), Precoding Matrix Indicator (PMI for short), and rank Indicator (RI for short).

The CQI is an index for measuring the quality of the downlink channel. In the 36-213 protocol, the CQIs are expressed by integer values of 0 to 15, and represent different CQI levels, and the different CQIs correspond to respective modulation schemes and coding rates (MCSs).

The RI is used to describe the number of spatially independent channels, corresponding to the rank of the channel response matrix. In the open-loop spatial multiplexing mode and the closed-loop spatial multiplexing mode, the UE needs to feed back RI information, and in other modes, the RI information does not need to be fed back. The channel matrix has a rank corresponding to the number of layers.

In the prior art, an idea is to change the conventional method for constructing an 8-antenna codebook to perform feedback of subband PMI channel information, and instead, the UE feeds back a 4-antenna PMI1, the base station finds a corresponding codeword WPMI1 from the 4-antenna codebook, and also feeds back a PMI2, the base station finds a corresponding codeword WPMI2 from another 2-antenna codebook, and combines the WPMI1 and the WPMI2 by using a functional relationship to jointly form matrix representation channel information of an 8-antenna, and the principle is as shown in fig. 1.

The 4 antennas with the same polarization direction are equivalent to one Virtual Port (Virtual Port1), and the 4 antennas with other polarization directions are equivalent to another Virtual Port (Virtual Port2), which respectively correspond to 1 PMI1 with 4 antennas and 1 PMI2 with 2 antennas. The functional relationship of the two can be a product or a Kronecker product (the operator is expressed as Kronecker)) In a form that is more suitable for the characteristics of dual polarized channels.

The PMI1 may be configured as long-term feedback or as shared feedback for widebands, and the PMI2 may be configured as short-term or single Subband feedback or as feedback for a few subbands (Multi-subbands). And the overhead is saved under the condition of low Rank with stronger channel correlation.

The eigenvector information/precoding information of the channel can be expressed as:

[\begin{matrix} WPMI 1 & O \\ O & WPMI 1 \end{matrix}] WPMI 2,

where O denotes a zero matrix, and WPMI2 denotes a 2 × 1 matrix (when Rank 1) or a 2 × 2 matrix (Rank2), the UE employs codebook form feedback.

The method utilizes some characteristics of the dual-polarized antenna, and can effectively solve the problem of channel information feedback of the 8-antenna dual-polarized channel in the low Rank.

But for the case where Rank > 2, 4 antennas cannot simply be equated to 1 virtual antenna port (since performance is greatly affected). In addition, this method is relatively complicated in the design of the codebook corresponding to WPMI2 in the cases of Rank3, 5, 7, and the like.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method and a device for acquiring channel information, which solve the technical defect that a terminal in the prior art cannot flexibly send channel information according to specific needs.

In order to solve the above technical problem, the present invention provides a method for acquiring channel information, including:

the terminal transmits Rank Indicator (RI) information, first codebook index indication (PMI1) information and second codebook index indication (PMI2) information of a current channel to a base station; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

the base station finds an 8 multiplied by upsilon matrix W1 from an 8 antenna codebook according to the RI information and PMI1 information, and finds a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and PMI2 information;

the base station adjusts the phase of each element in the matrix W1 according to the matrix W1, the matrix W2 and a function F (W1, W2), so as to obtain an adjustment matrix, and the adjustment matrix is used as the channel information of the sub-band.

The function F (W1, W2) is agreed by the terminal and the base station together.

Preferably, the 8 x υ matrix W1 is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yAnd y is a positive integer from 1 to upsilon at different times.

Preferably, said a_1yAnd a_2yIs an element or 0 in the 8PSK alphabet.

Preferably, the base station obtains the adjustment matrix according to the function F (W1, W2), including:

the base station adjusts the phase of each element in the matrix W1 by taking a 4-dimensional vector as a unit according to the function F (W1, W2), and the obtained adjustment matrix is

Wherein M is_yIs a 4-dimensional vector, A_1yAnd A_2yIs constant and A_1yAnd A_2yAnd y is a positive integer from 1 to upsilon at different times.

Preferably, the matrix W2 is an 8 × 8 orthogonal rotation matrix; or

The matrix W2 is a 2 x upsilon matrixc_1yAnd c_2yIs a constant, y is a positive integer from 1 to upsilon; or

The matrix W2 is an 8 x upsilon matrixJ is a 4 × 1 all-1 vector.

Preferably, when the matrix W2 is an 8 × 8 orthogonal rotation matrix, the function F (W1, W2) is W2 × W1;

the matrix W2 is a 2 x upsilon matrixWhen the function is Wherein M is_yIs a 4-dimensional vector; c. C_1yAnd c_2yIs a constant; a is_1yAnd a_2yIs constant and a_1yAnd a_2yNot simultaneously 0, y is a positive integer from 1 to upsilon;

the matrix W2 is an 8 x upsilon matrixThe function F (W1, W2) represents the dot product operation of the matrix W2 and the matrix W1.

Preferably, the

f_1 (W 1) = (\begin{matrix} \begin{matrix} b_{11} M_{1} & b_{12} M_{2} & . . . & b_{1 r} M_{r} \end{matrix} & O \\ O & \begin{matrix} b_{21} M_{1} & B_{22} M_{2} & . . . & b_{2 r} M_{r} \end{matrix} \end{matrix});

Wherein b is_1zAnd b_2zIs a constant, z is a positive integer from 1 to r.

In order to solve the above technical problem, the present invention further provides a method for acquiring channel information, including:

the terminal sends Rank Indicator (RI) information and first codebook index indication (PMI1) information of a current channel to a base station; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

the base station finds an 8 multiplied upsilon matrix W1 from an 8 antenna codebook according to the RI information and PMI1 information, and obtains a matrix W2 according to convention;

Preferably, the 8 x υ matrix W1 is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yIs not simultaneousIs 0 and y is a positive integer from 1 to upsilon.

10. The method of claim 8 wherein the step of the base station obtaining the adjustment matrix according to the function F (W1, W2) comprises:

the terminal at least sends Rank Indicator (RI) information and first codebook index indication (PMI1) information of a current channel to a base station, and when upsilon is less than or equal to 2, the terminal also sends second codebook index indication (PMI2) information to the base station; wherein the rank indicator indicates the rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

when upsilon is less than or equal to 2, the base station finds an 8 x upsilon matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and takes the matrix W1 as the channel information of the subband; the base station finds a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and the PMI2 information, adjusts the phase of each element in the matrix W1 according to the matrix W1, the matrix W2 and a function F1(W1, W2) to obtain an adjustment matrix, and takes the adjustment matrix as the channel information of the subband; or

When upsilon is less than or equal to 2, the base station finds 1 4 x upsilon matrixes W1 from one 4-antenna codebook according to the RI information and the PMI1 information, finds a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and the PMI2 information, and obtains channel information of the subband under 8 antennas according to the matrix W1, the matrix W2 and a function F2(W1, W2);

when upsilon is larger than 2, the base station finds an 8 x upsilon matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and takes the matrix W1 as the channel information of the subband.

In order to solve the above technical problem, the present invention further provides an apparatus for acquiring channel information, including:

a receiving module, configured to receive Rank Indicator (RI) information, first codebook index indication (PMI1) information, and second codebook index indication (PMI2) information of a current channel, which are sent by a terminal; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

the searching module is used for finding an 8 x upsilon matrix W1 from an 8-antenna codebook according to the RI information and the PMI1 information, and finding a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and the PMI2 information;

an obtaining module, configured to adjust a phase of each element in the matrix W1 according to the matrix W1, the matrix W2, and a function F (W1, W2), to obtain an adjustment matrix, and use the adjustment matrix as channel information of the subband.

Preferably, the matrix W1 used by the lookup module for lookup is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yAnd y is a positive integer from 1 to upsilon at different times.

Preferably, the obtaining module is configured to adjust the phase of each element in the matrix W1 by taking a 4-dimensional vector as a unit according to the function F (W1, W2), and the obtained adjustment matrix is

a receiving module, configured to receive Rank Indicator (RI) information and first codebook index indication (PMI1) information of a current channel, which are sent by a terminal; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

the searching module is used for finding an 8 x upsilon matrix W1 from an 8 antenna codebook according to the RI information and the PMI1 information and obtaining a matrix W2 according to convention;

Another technical problem to be solved by the present invention is to provide a codebook construction method for feeding back channel information, so as to solve the technical defect that a terminal in the prior art cannot flexibly send channel information according to specific needs.

In order to solve the above technical problem, the present invention further provides a codebook construction method, where the codebook is used for feedback of channel information, and the codebook construction method includes:

selecting a first orthogonal matrix A of N8 multiplied by 2r block diagonals_nAnd N second orthogonal matrixes B are selected_n；

According to the first orthogonal matrix A_nAnd a second orthogonal matrix B_nConstructing N8 x 2r matrices M by means of multiplication_n；

From the matrix M_nAnd selecting one or more columns to generate part or all of code words in the sub-codebook of each Rank under 8 antennas to obtain the codebook.

Preferably, when r is 4, the first orthogonal matrix A_nIs composed of

[\begin{matrix} W_{n} & O \\ O & W_{n} \end{matrix}],

O is a zero matrix;

the matrix W_nThe same as in the LTE 4Tx codebook.

Preferably, when r is 4, the second orthogonal matrix B_nIs composed ofOr

The matrixWherein

Compared with the prior art, the technical scheme of the invention provides a simple and unified channel information feedback technology under 8 antennas, and can solve the feedback problem of each Rank.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic diagram of matrix characterization channel information of 8 antennas in the prior art;

FIG. 2 is a schematic flow chart according to a first embodiment of the present invention;

FIG. 3 is a schematic flow chart of a second embodiment of the present invention;

FIG. 4 is a flow chart of a third embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a fourth embodiment of the present invention;

fig. 6 is a schematic structural diagram of a fifth embodiment of the present invention.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided with reference to the accompanying drawings, embodiments and/or application examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented.

First, if not conflicting, embodiments of the present invention and individual features of the embodiments may be combined with each other within the scope of protection of the present invention. Additionally, the steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions and, although a logical order is illustrated in the flow charts, in some cases, the steps illustrated or described may be performed in an order different than here.

For one Subband, the UE feeds back at least RI information v, and the first codebook index indicates information PMI 1.

When the RI is less than or equal to 2, the UE also feeds back a second codebook index indication information PMI 2.

The base station finds an 8 multiplied by upsilon matrix W1 from an 8 antenna codebook according to RI and PMI 1. The base station finds a corresponding matrix W2 from another codebook according to the PMI2 or according to the RI and the PMI2, and adjusts the phase of each element in the W1 according to F (W1, W2) so as to obtain channel information of a Subband.

Or the base station finds 1 4 × ν matrix W1 from one 4-antenna codebook according to RI and PMI1, and the base station finds the corresponding matrix W2 from another codebook according to PMI2 or RI and PMI2, and obtains the channel information of the next Subband with 8 antennas according to F (W1, W2).

When Rank is larger than 2, the UE feeds back 1 PMI1, and the base station finds an 8 x upsilon matrix W1 from an 8-antenna codebook according to RI and PMI 1. Thereby obtaining channel information of the next sub band of 8 antennas.

For one Subband, the UE feeds back RI information upsilon, first codebook index indication information PMI1 and second codebook index indication information PMI 2. The base station finds an 8 multiplied by upsilon matrix W1 from an 8 antenna codebook according to RI and PMI 1. The base station finds a corresponding matrix W2 from another codebook according to the PMI2 or according to the RI and the PMI2, and adjusts the phase of each element in the W1 according to F (W1, W2) so as to obtain channel information of a Subband.

The PMI1 of the present invention corresponds to an 8-antenna codebook with respect to the prior art. The channel information can be quantized only by using the PMI1, the PMI2 is suitable for the case of Rank1-8, the PMI2 is used for feeding back the W2, and the base station adjusts the phase of an element in W1 corresponding to the PMI1 according to the W2 to obtain the effect of enhancing the feedback precision. The phase adjustment may be performed in units of 4 × 1 vectors. In low rank, the invention can have the same technical effect as the prior art. And a more uniform feedback structure is provided when the feedback problem of high rank and the condition of low rank are solved.

The 8 x upsilon W1 matrix has the following characteristics:

w1 isForm (A) of₁，M₂......M_υIs a 4-dimensional vector, and can be equal orNot equal; and upsilon is a positive integer not greater than 8 and represents the RI value.

Wherein a is₁₁ a₁₂......a_1υ，a₂₁ a₂₂......a_2υEtc. are all constants. Further may be an 8PSK alphabet centering element or 0. The 8PSK alphabet set isWherein if a_1jIs 0 then a_2jAnd must not be 0.

W1 isIn the form of (1), the corresponding codebook can be obtained by the following construction method of 8 antenna codebooks:

selecting K4 × n matrixes A and K2 × m matrixes B, and usingOrForming K8 (mn) matrices and using the columns therein to form codewords in a codebook

Selecting K8 multiplied by n matrixes A and n multiplied by m matrixes B, forming K8 multiplied by m matrixes by using the A multiplied by B and forming code words in a codebook by using columns in the matrixes;

the F (W1, W2) function phase adjusts W1 based on W2, preferably in units of 4 × 1 vectors, with the following results:

in the form of (1). A. the₁₁ A₁₂......A_1υ，A₂₁ A₂₂......A_2υEtc. are all constants. Further may be an 8PSK alphabet centering element or 0. The 8PSK alphabet set isIf A is_1jIs 0 then A_2jAnd must not be 0. j is a positive integer not less than v.

Preferably, F (W1, W2) and W2 may be the following cases:

w2 is an 8 × 8 matrix, F (W1, W2) ═ W2 × W1; a further W2 may be a diagonal matrix.

Preferably, F (W1, W2) may be the following:

f (W1, W2) ═ F _2(W2) × W1, F _2(W2) is an 8 × 8 matrix;

preferably, F (W1, W2) may be the following: :

f _1 (W1). times.W 2, f _1(W1) is a matrix of 8 × 2r, r being an integer.

f _1(W1) takes the form:

(\begin{matrix} \begin{matrix} b_{11} M_{1} & b_{12} M_{2} & . . . & b_{1 r} M_{r} \end{matrix} & O \\ O & \begin{matrix} b_{21} M_{1} & B_{22} M_{2} & . . . & b_{2 r} M_{r} \end{matrix} \end{matrix})

r is not more than upsilon.

b₁₁ b₁₂......b_1r，b₂₁ b₂₂......b_2rConstant, further 8PSK alphabet concentrating elements

F (W1, W2) may be the following:

for example, W2 is a 2 x upsilon momentMatrix of

W2 is a matrix of 8 x upsilon

J is a 4 × 1 all-1 vector.

F (W1, W2) represents the dot product form of W2 and W1.

In the technical scheme of the invention, for one sub, UE at least sends a Rank Indicator (RI) of a current channel and first codebook index indication information PMI1 to a base station; the RI information is used for indicating the rank (upsilon) of the current channel, and the upsilon is a positive integer not greater than 8; after receiving the PMI1 information and RI information, the base station finds an 8 × ν matrix W1 from an 8-antenna codebook according to the RI and PMI1, and represents the matrix W1 as channel information of the sub-band, so as to obtain channel information of the next sub-band with 8 antennas.

A first embodiment of the method for acquiring channel information is applicable to when υ is less than or equal to 2, as shown in fig. 2, the method mainly includes:

step S210, UE sends RI information upsilon and first codebook index indication information PMI1 of the current channel to a base station, and also sends second codebook index indication information PMI 2;

step S220, after receiving the PMI1, the PMI2 and the RI information, the base station finds an 8 × upsilon matrix W1 from an 8-antenna codebook according to the RI and the PMI1, and finds a corresponding matrix W2 from another codebook according to the PMI2 or the RI and the PMI 2;

in step S230, the base station adjusts the phase of each element in the matrix W1 according to the matrix W1, the matrix W2 and the function F1(W1, W2), so as to obtain an adjustment matrix, and uses the adjustment matrix as the channel information of the sub-band, thereby obtaining the channel information of the sub-band.

In the step S220, the base station may also find 1 4 × ν matrix W1 from one 4-antenna codebook according to RI and PMI1, and find a corresponding matrix W2 from another codebook according to PMI2 or RI and PMI 2; accordingly, in step S230, the bs obtains the channel information of the sub band under 8 antennas according to the matrix W1, the matrix W2 and the function F2(W1, W2).

The function F1(W1, W2) or F2(W1, W2) represents a dot product operation of W2 and W1.

In a second embodiment, a method for acquiring channel information is applicable to when upsilon is greater than 2 (or Rank > 2), as shown in fig. 3, the method mainly includes the following steps:

step S310, the UE sends the PMI1 and the RI information to the base station;

step S320, after receiving the PMI1 and RI information, the base station finds an 8 × ν matrix W1 from an 8-antenna codebook according to the RI and PMI1, and represents the matrix W1 as channel information of the sub-band, thereby obtaining channel information of the next sub-band with 8 antennas.

In a third embodiment, for a sub band, as shown in fig. 4, a method for acquiring channel information mainly includes the following steps:

step S410, UE sends RI information upsilon of the current channel, first codebook index indication information PMI1 and second codebook index indication information PMI2 to a base station;

step S420, after receiving the PMI1, the PMI2 and the RI information, the base station finds an 8 × upsilon matrix W1 from an 8-antenna codebook according to the RI and the PMI1, and finds a corresponding matrix W2 from another codebook according to the PMI2 or the RI and the PMI 2;

in step S430, the base station adjusts the phase of each element in the matrix W1 according to a function F (W1, W2) to obtain an adjustment matrix, and uses the adjustment matrix as the channel information of the sub-band, thereby obtaining the channel information of the sub-band.

The above-mentioned 8 × υ matrix W1 may have the following characteristics:

wherein M is₁ M₂......M_υEach is a 4-dimensional vector, which may be equal or unequal; upsilon is a positive integer not greater than 8 and represents the RI value; a is₁₁、a₁₂A_1υ，a₂₁、a₂₂A_2υAre all constants, and further can be elements in 8PSK letter set or 0; the 8PSK alphabet set isWherein if a_1yAnd a_2yAnd y is a positive integer from 1 to upsilon at different times.

Matrix of 8 x upsilonThen, the corresponding codebook can be obtained by the following construction method of 8 antenna codebooks:

selecting K4 × n matrixes A and K2 × m matrixes B, and usingOrForming K8 (mn) matrices, and forming codewords in a codebook using columns in the K8 (mn) matrices; or

K8 x n matrices A and n x m matrices B are selected, A x B is used to form K8 x m matrices, and columns in the K8 x m matrices are used to form codewords in the codebook.

The adjustment matrix is obtained by performing phase adjustment on the matrix W1 according to the F (W1, W2) (i.e. adjusting the phase of each element in W1 according to F (W1, W2) and preferably by taking a 4 × 1 vector as a unit, and the obtained adjustment matrix is:

wherein:

A₁₁、A₁₂._1υ，A₂₁、A₂₂._2υAre all constants, and further may be an element or 0 in the 8PSK alphabet set, where the 8PSK alphabet set isIf A is_1yAnd A_2yAnd y is a positive integer from 1 to upsilon at different times.

The function F (W1, W2) may be agreed upon by both the base station and the terminal.

Preferably, F (W1, W2) and W2 may be the following cases:

w2 is an 8 × 8 orthogonal rotation matrix, F (W1, W2) ═ W2 × W1; a further W2 may be a diagonal matrix.

Preferably, F (W1, W2) may be the following:

f (W1, W2) ═ F _2(W2) × W1, and F _2(W2) is an 8 × 8 matrix. For the matrix W2, the base station may also be configured to use a fixed or a predetermined value directly without feedback.

Preferably, F (W1, W2) may be the following:

f _1(W1) xW 2, f _1(W1) is a matrix of 8 x 2r, r is an integer;

wherein,wherein r is less than or equal to upsilon; b₁₁、b₁₂._1r，b₂₁、b₂₂._2rAre all constants, and further are elements in the 8PSK alphabet set.

F (W1, W2) may be the following:

for example, W2 is a 2 x upsilon matrixThen c_1yAnd c_2yIs constant and y is a positive integer from 1 to υ.

W2 is a matrix of 8 x upsilonJ is a 4 × 1 full 1 vector, and the function F (W1, W2) represents a dot product operation of the matrix W2 and the matrix W1.

Application example one, a codebook construction method, where the codebook is used for feedback of channel information, includes:

When r is 4, the first orthogonal matrix A_nIs composed of

[\begin{matrix} W_{n} & O \\ O & W_{n} \end{matrix}],

O is a zero matrix;

the matrix W_nThe same as in the LTE 4Tx codebook.

When r is 4, the second orthogonal matrix B_nIs composed of

Or

The matrixWherein

The codebook for W1 is shown in table 3:

(M in this application example)_nAnd M_n，mIs defined locally, differently from the previous definition)

Table 3, codebook schematic for W1

<math> <mrow> <msub> <mi>M</mi> <mi>n</mi> </msub> <mo>=</mo> <msub> <mi>B</mi> <mi>n</mi> </msub> <mo>&CircleTimes;</mo> <msub> <mi>A</mi> <mi>n</mi> </msub> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> <mtr> <mtd> <mo>-</mo> <mn>1</mn> </mtd> <mtd> <mn>1</mn> </mtd> </mtr> </mtable> </mfenced> <mo>&CircleTimes;</mo> <msub> <mi>W</mi> <mi>n</mi> </msub> </mrow> </math>

Index

Rank1

Rank2

Rank3

Rank4

0	M₀(：，1)	[M₀(：，1)M₀(：，5)]	[M₀(：，1)M₀(：，4)M₀(：，5)]	[M₀(：，1)M₀(：，4)M₀(：，5)M₀(：，8)]
					1	M₁(：，1)	[M₁(：，1)M₁(：，5)]	[M₁(：，1)M₁(：，2)M₁(：，5)]	[M₁(：，1)M₁(：，2)M₁(：，5)M₁(：，6)]
2	M₂(：，1)	[M₂(：，1)M₂(：，5)]	[M₂(：，1)M₂(：，2)M₂(：，5)]	[M₂(：，1)M₂(：，2)M₂(：，5)M₂(：，6)]
					3	M₃(：，1)	[M₃(：，1)M₃(：，5)]	[M₃(：，1)M₃(：，2)M₃(：，5)]	[M₃(：，1)M₃(：，2)M₃(：，5)M₃(：，6)]
4	M₄(：，1)	[M₄(：，1)M₄(：，5)]	[M₄(：，1)M₄(：，4)M₄(：，5)]	[M₄(：，1)M₄(：，4)M₄(：，5)M₄(：，8)]
					5	M₅(：，1)	[M₅(：，1)M₅(：，5)]	[M₅(：，1)M₅(：，4)M₅(：，5)]	[M₅(：，1)M₅(：，4)M₅(：，5)M₅(：，8)]
6	M₆(：，1)	[M₆(：，1)M₆(：，5)]	[M₆(：，1)M₆(：，3)M₆(：，5)]	[M₆(：，1)M₆(：，3)M₆(：，5)M₆(：，7)]
					7	M₇(：，1)	[M₇(：，1)M₇(：，5)]	[M₇(：，1)M₇(：，3)M₇(：，5)]	[M₇(：，1)M₇(：，3)M₇(：，5)M₇(：，7)]
8	M₈(：，1)	[M₈(：，1)M₈(：，5)]	[M₈(：，2)M₈(：，5)M₈(：，6)]	[M₈(：，1)M₈(：，2)M₈(：，5)M₈(：，6)]
					9	M₉(：，1)	[M₉(：，1)M₉(：，5)]	[M₉(：，4)M₉(：，5)M₉(：，8)]	[M₉(：，1)M₉(：，4)M₉(：，5)M₉(：，8)]
10	M₁₀(：，1)	[M₁₀(：，1)M₁₀(：，5)]	[M₁₀(：，3)M₁₀(：，5)M₁₀(：，7)]	[M₁₀(：，1)M₁₀(：，3)M₁₀(：，5)M₁₀(：，7)]
					11	M₁₁(：，1)	[M₁₁(：，1)M₁₁(：，5)]	[M₁₁(：，3)M₁₁(：，5)M₁₁(：，7)]	[M₁₁(：，1)M₁₁(：，3)M₁₁(：，5)M₁₁(：，7)]
12	M₁₂(：，1)	[M₁₂(：，1)M₁₂(：，5)]	[M₁₂(：，2)M₁₂(：，5)M₁₂(：，6)]	[M₁₂(：，1)M₁₂(：，2)M₁₂(：，5)M₁₂(：，6)]
					13	M₁₃(：，1)	[M₁₃(：，1)M₁₃(：，5)]	[M₁₃(：，3)M₁₃(：，5)M₁₃(：，7)]	[M₁₃(：，1)M₁₃(：，3)M₁₃(：，5)M₁₃(：，7)]
14	M₁₄(：，1)	[M₁₄(：，1)M₁₄(：，5)]	[M₁₄(：，3)M₁₄(：，5)M₁₄(：，7)]	[M₁₄(：，1)M₁₄(：，3)M₁₄(：，5)M₁₄(：，7)]
					15	M₁₅(：，1)	[M₁₅(：，1)M₁₅(：，5)]	[M₁₅(：，2)M₁₅(：，5)M₁₅(：，6)]	[M₁₅(：，1)M₁₅(：，2)M₁₅(：，5)M₁₅(：，6)]

When upsilon is larger than 4 (or Rank > 4), a column vector is also extracted from Mn to construct a code word, which is a better application suitable for reducing bit (bit) overhead and can be obtainedIs shaped asThe code word of (1).

The more general case is:

the code words in the codebook are all formed by M_m，nIs formed by the column vectors of (1). Such as: a. the_mIs W₀～W₁₅，B_nIs composed ofAnd(or its rows swapped). This enables the construction of 32 matrices M_m，nAll code words in the code book are formed by column vectors in the code words, and the column vectors in the same code word can be from different M_m，n。

It is worth pointing out that it is possible to,the front and back objects can be exchanged with each other, and the matrix can be arbitrarily exchanged in rows and columns without affecting the performance of the codeword.

The codebook corresponding to W1 and the construction method are as follows:

wherein

From M_nThe column vector is selected to construct W1 corresponding to the code word in the codebook. Similar to the form using the Kronecker product, the more general case is M_m，n＝A_mB_n，A_mIs composed ofB_nIs composed ofThis enables the construction of 32 matrices M_m，nAll code words in the code book are formed by column vectors in the code words, and the column vectors in the same code word can be from different M_m，n。

The code words in the codebook corresponding to the matrix W1 obtained by the construction method all haveThe structure of (1). The matrix W1 conforms to the dual polarization channel characteristics and can be used for channel information feedback alone. When the matrix W2 is present, the feedback accuracy of the channel information is higher.

Application example two

When the UE feedback v is 1, the base station finds a codeword W1 according to the RI and PMI1 sent by the UE, which is in the form of:

PMI2, W2 corresponds to a codebook in which all codewords are 8 × 8 matrices, such as a 2-bit codebook, and includes the following 4 codewords:

and

f (W1, W2) ═ W2 × W1; such as

Then, obtaining:

application example three

In this application example, the codebook corresponding to the W2 and PMI2 in the second application example is:

[\begin{matrix} 1 & 0 \\ 0 & - 1 \end{matrix}],

[\begin{matrix} 1 & 0 \\ 0 & 1 \end{matrix}],

[\begin{matrix} 1 & 0 \\ 0 & j \end{matrix}]

and

[\begin{matrix} 1 & 0 \\ 0 & - j \end{matrix}];

or,

[\begin{matrix} 1 \\ 1 \end{matrix}]

[\begin{matrix} 1 \\ - j \end{matrix}],

[\begin{matrix} 1 \\ j \end{matrix}]

and

[\begin{matrix} 1 \\ - 1 \end{matrix}] .

using f _2(W2) to transform W2 into 8 × 8 codebook form in application example two, and then multiplying by W1, namely:

f (W1, W2) ═ F _2(W2) × W1, where F _2(W2) is an 8 × 8 matrix;

in addition, F (W1, W2) may also be equal to:

f _1 (W1). times.W 2, wherein f _1(W1) is a matrix of 8 x 2r, and r is an integer.

Application example four

The function f _1(W1) is used on W1 to morph to the following form:

k is less than or equal to upsilon; b₁₁、b₁₂._1r，b₂₁、b₂₂.._2rAre all constants, and further are 8PSK alphabet elements.

Such as

Will be provided with

The following steps are changed:

or

Will be provided with

The following steps are changed:

when r + k is upsilon, such as Rank2, 1W 1 is sent asThe W1 is transformed intoW2 is a codeword in 1 2 x 2 codebook, e.g.Then:

application example five

W2 is a 2 x upsilon matrix, equal to

W2 is a fixed value, or W2 is determined according to RI, different RI corresponds to different W2, or W2 is determined by RI and PMI2 together. When v is 1, PMI2 is fixedWhen upsilon is 2, PMI is fixedAnd so on. At this timeII is a full 1 matrix of 8 x upsilon, x is the mathematical operator of the dot product.

In other application examples of the invention, W2 is an 8 x upsilon matrixJ is a 4 × 1 all-1 vector.

In other embodiments of the present invention, W1 isW2 is 1 identity matrix, no feedback.

In a fourth embodiment, as shown in fig. 5, an apparatus for acquiring channel information mainly includes a receiving module 510, a searching module 520, and an acquiring module 530, where:

a receiving module 510, configured to receive Rank Indicator (RI) information, first codebook index indication (PMI1) information, and second codebook index indication (PMI2) information of a current channel, which are sent by a terminal; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

a searching module 520, connected to the receiving module 510, configured to find an 8 × ν matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and find a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and PMI2 information;

an obtaining module 530, connected to the searching module 520, is configured to adjust the phase of each element in the matrix W1 according to the matrix W1, the matrix W2, and a function F (W1, W2), so as to obtain an adjustment matrix, and use the adjustment matrix as the channel information of the subband.

Wherein the matrix W1 used by the lookup module 520 for lookup is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yAnd y is a positive integer from 1 to upsilon at different times.

Wherein the obtaining module 530 is configured to adjust the phase of each element in the matrix W1 by taking the 4-dimensional vector as a unit according to the function F (W1, W2), and the obtained adjustment matrix is

In a fifth embodiment, as shown in fig. 6, an apparatus for acquiring channel information mainly includes a receiving module 610, a searching module 620, and an acquiring module 630, where:

a receiving module 610, configured to receive Rank Indicator (RI) information and first codebook index indication (PMI1) information of a current channel, which are sent by a terminal; wherein the RI information indicates a rank (upsilon) of the current channel, and upsilon is a positive integer not greater than 8;

a searching module 620, connected to the receiving module 610, for finding an 8 × ν matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and for obtaining a matrix W2 according to a convention;

an obtaining module 630, connected to the searching module 620, is configured to adjust the phase of each element in the matrix W1 according to the matrix W1, the matrix W2, and a function F (W1, W2), so as to obtain an adjustment matrix, and use the adjustment matrix as the channel information of the subband.

Wherein the matrix W1 used by the lookup module 620 for lookup is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yAnd y is a positive integer from 1 to upsilon at different times.

The obtaining module 630 is configured to adjust the phase of each element in the matrix W1 by taking the 4-dimensional vector as a unit according to the function F (W1, W2), and the obtained adjustment matrix is

Compared with the prior art, the PMI1 of the invention corresponds to an 8-antenna codebook. The channel information can be quantized only by using the PMI1, the PMI2 is suitable for the case of Rank1-8, the PMI2 is used for feeding back the W2, and the base station adjusts the phase of an element in W1 corresponding to the PMI1 according to the W2 to obtain the effect of enhancing the feedback precision. The phase adjustment may be performed in units of 4 × 1 vectors. In low rank, the invention can have the same technical effect as the prior art. And a more uniform feedback structure is provided when the feedback problem of high rank and the condition of low rank are solved.

Those skilled in the art will appreciate that the modules or steps of the invention described above can be implemented in a general purpose computing device, centralized on a single computing device or distributed across a network of computing devices, and optionally implemented in program code that is executable by a computing device, such that the modules or steps are stored in a memory device and executed by a computing device, fabricated separately into integrated circuit modules, or fabricated as a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.

Although the embodiments of the present invention have been described above, the above descriptions are only for the convenience of understanding the present invention, and are not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for acquiring channel information is characterized by comprising the following steps:

the terminal sends Rank Indicator (RI) information, first codebook index indication (PMI1) information and second codebook index indication (PMI2) information of a current channel to a base station; wherein the RI information indicates the rank upsilon of the current channel, and upsilon is a positive integer not greater than 8;

the base station adjusts the phase of each element in the matrix W1 according to the matrix W1, the matrix W2 and a function F (W1, W2) to obtain an adjustment matrix, and the adjustment matrix is used as the channel information of the sub-band;

the function F (W1, W2) is agreed by the terminal and the base station together;

wherein,

the 8 x υ matrix W1 is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yNot simultaneously 0, y is a positive integer from 1 to upsilon;

the base station obtains the adjustment matrix according to the function F (W1, W2), including:

2. The method of claim 1, wherein:

a is a_1yAnd a_2yIs an element or 0 in the 8PSK alphabet.

3. The method of claim 1, wherein:

the matrix W2 is an 8 × 8 orthogonal rotation matrix; or

The matrix W2 is an 8 x upsilon matrixJ is a 4 × 1 all-1 vector.

4. The method of claim 3, wherein:

when the matrix W2 is an 8 × 8 orthogonal rotation matrix, the function F (W1, W2) is W2 × W1;

5. The method of claim 4, wherein:

the

Wherein b is_1zAnd b_2zIs a constant, z is a positive integer from 1 to r.

6. A method for acquiring channel information is characterized by comprising the following steps:

the terminal sends the rank indicator RI information and the first codebook index indication PMI1 information of the current channel to the base station; wherein the RI information indicates the rank upsilon of the current channel, and upsilon is a positive integer not greater than 8;

wherein,

the step of the base station obtaining the adjustment matrix according to the function F (W1, W2) includes:

7. A method for acquiring channel information is characterized by comprising the following steps:

the terminal at least sends Rank Indicator (RI) information and first codebook index indication (PMI) 1 information of a current channel to a base station, and when upsilon is less than or equal to 2, the terminal also sends second codebook index indication (PMI2) information to the base station; wherein the rank indicator indicates the rank upsilon of the current channel, and upsilon is a positive integer not greater than 8;

when upsilon is less than or equal to 2, the base station finds an 8 x upsilon matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and takes the matrix W1 as the channel information of a subband; the base station finds a corresponding matrix W2 from another codebook according to the PMI2 information or the RI information and the PMI2 information, adjusts the phase of each element in the matrix W1 according to the matrix W1, the matrix W2 and a function F1(W1, W2) to obtain an adjustment matrix, and takes the adjustment matrix as the channel information of the subband; or

when upsilon is larger than 2, the base station finds an 8 x upsilon matrix W1 from an 8-antenna codebook according to the RI information and PMI1 information, and takes the matrix W1 as the channel information of the subband;

wherein,

8. An apparatus for acquiring channel information, comprising:

a receiving module, configured to receive rank indicator RI information of a current channel, first codebook index indication PMI1 information, and second codebook index indication PMI2 information sent by a terminal; wherein the RI information indicates the rank upsilon of the current channel, and upsilon is a positive integer not greater than 8;

an obtaining module, configured to adjust a phase of each element in the matrix W1 according to the matrix W1, the matrix W2, and a function F (W1, W2), to obtain an adjustment matrix, and use the adjustment matrix as channel information of a subband;

wherein,

the matrix W1 used by the lookup module for lookup is equal toWherein M is_yIs a 4-dimensional vector, a_1yAnd a_2yIs constant and a_1yAnd a_2yNot simultaneously 0, y is a positive integer from 1 to upsilon;

the obtaining module is used for adjusting the phase of each element in the matrix W1 by taking a 4-dimensional vector as a unit according to the function F (W1, W2), and the obtained adjustment matrix is

9. An apparatus for acquiring channel information, comprising:

a receiving module, configured to receive rank indicator RI information and first codebook index indication PMI1 information of a current channel sent by a terminal; wherein the RI information indicates the rank upsilon of the current channel, and upsilon is a positive integer not greater than 8;

an obtaining module, configured to adjust a phase of each element in the matrix W1 according to the matrix W1, the matrix W2, and a function F (W1, W2), to obtain an adjustment matrix, where the adjustment matrix is used as channel information of a subband;

wherein,

10. A codebook construction method, the codebook being used for feedback of channel information, comprising:

From the momentMatrix M_nSelecting one or more columns to generate partial or all code words in a sub-codebook of each Rank under 8 antennas to obtain the codebook;

when r is 4, the first orthogonal matrix A_nIs composed ofO is a zero matrix;

the matrix W_nThe same as in the LTE 4Tx codebook;

when r is 4, the second orthogonal matrix B_nIs composed ofOr

The matrixWherein