CN108234002A - A kind of method and device for constructing multiple antennas precoding - Google Patents

Abstract

The embodiment of the invention discloses a kind of method and devices for constructing multiple antennas precoding.The method includes：Obtain long-term precoding W1 and short-term precoding W2, the W1 is the form of block diagonal matrix, diagonal entry be by the part Column vector groups in the Discrete Fourier transform of over-sampling into；The W2 is used to carry out linear combination to the vector included in the W1；It is the product of long-term precoding W1 and short-term precoding W2 to obtain total pre-coding matrix W, total pre-coding matrix W according to the long-term precoding W1 and short-term precoding W2.The present invention utilizes new short-term codebook construction mode by suitably increasing the feedback quantity of short-term code book so that ultimately constructed precoding can the approaching to reality ground characteristic of channel to the greatest extent, effectively enhance the performance of existing code book.

Description

Method and device for constructing multi-antenna precoding

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a method and a device for constructing multi-antenna precoding.

Background

To further improve the single-user transmission rate and the system capacity of the wireless communication system, the third Generation Partnership project (3 GPP) introduced a 16-port full-dimensional MIMO (FD-MIMO, also referred to as massive MIMO) in Release 13 version of Long Term Evolution (LTE) and further increased to 32-port in Release 14 version. Will be further increased in future 5G communication systems.

More antenna ports can support higher-order Multiple-Input Multiple-Output (MIMO) transmission, but also increase the complexity of channel estimation and channel information feedback. Particularly, in a Frequency Division Duplex (FDD) system, the UE needs to inform the base station of information related to a downlink channel through a feedback channel, and in order to quantify status information of the downlink channel, the 3GPP introduces a precoding concept. The terminal quantizes the downlink channel by using the set of codebook and feeds back related precoding information to the base station, so that the base station can conveniently carry out downlink channel precoding construction. Therefore, the channel quantization precision has this decisive influence on the system performance, but the higher the quantization precision is, the larger the feedback information is, so an efficient and flexible precoding construction method is needed to improve the channel quantization precision under the condition that the increase of the feedback quantity is not obvious.

In order to reduce the feedback amount, 3GPP introduced a double codebook structure in Release 10, that is, the codebook form is W ═ W₁*W₂. Wherein W₁Called long-term codebook, quantizes the long-term statistical properties of the channel, W₂Referred to as a short-term codebook, quantizes the short-term characteristics of the channel. Generally, the long-term statistical characteristic of the channel is considered to be relatively stable, so that a longer feedback period can be adopted, and the short-term channel characteristic can be a shorter feedback period, so that compared with the method of directly feeding back the overall characteristic of the W, the scheme greatly reduces the required feedback overhead.

In the current long-term codebook feedback, a maximum of 4 selectable beams are fed back at a time, and for low Rank transmission (Rank <7), the short-term codebook selects only partial beams from the 4 selectable beams and adjusts the beam phase between different polarization directions. This approach actually only uses the channel characteristics in some directions, which is clearly a gap from the true channel characteristics. The presently disclosed enhancement scheme involves linear combining of the first 4 beams fed back directly, but is limited by the amount of feedback, and only takes into account the phase characteristics between the different beams. The other scheme requires feedback and construction of a group of orthogonal codebooks, the short-term codebooks simultaneously adjust the amplitude and the phase of the orthogonal codebooks, and the combined codebook information is utilized to approach the characteristics of the channel to the maximum extent, so that the scheme is optimal theoretically, but each beam can independently adjust the amplitude and the phase, and the corresponding feedback quantity is also maximum.

Disclosure of Invention

The embodiment of the invention aims to provide a method and a device for constructing multi-antenna precoding, and aims to solve the problem how the finally constructed precoding can approach to the real channel characteristics to the greatest extent.

To achieve the purpose, the embodiment of the invention adopts the following technical scheme:

in a first aspect, a method of constructing multi-antenna precoding, the method comprising:

acquiring long-term precoding W1 and short-term precoding W2, wherein the W1 is in a form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

and acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2.

Preferably, the obtaining of the total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2 includes:

existing8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating precoding vector selection in a long-term precoding matrix; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.

Preferably, the long-term precodingWherein, theWhich contains 4 consecutive column vectors of the 8 x oversampled 4-th order DFT matrix.

Preferably, the precoding forms when the number of layers is 1 and 2 are respectively:

⊙ is a dot product operation, which means that corresponding elements of two vectors or matrixes are directly multiplied;

the above-mentionedSelected from the existing TM4 codebook of LTE

The above-mentionedRepresenting a window function, the optional window function comprising a rectangular window, a Hamming window, a Kaiser window or a Gaussian window function

The above-mentionedSelected from {1, -1, j, -j }

Preferably, theAccording to codebook index i in the TM4 codebook₂Vector of orientation

Construct its Householder transformation matrixAnd selecting the precoding matrix corresponding to the layer number v equal to 1.

Preferably, when the number of layers is 3,

or;

preferably, when the number of layers is 4,

wherein,is code book index i in TM4 codebook₂And v is 2.

Preferably, the number of layers is 5 and 6,

and

wherein,is code book index i in TM4 codebook₂And v is 3.

In a second aspect, an apparatus for constructing multi-antenna precoding, the apparatus comprising:

a first obtaining module, configured to obtain a long-term precoding W1 and a short-term precoding W2, where W1 is in the form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

a second obtaining module, configured to obtain a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, where the total precoding matrix W is a product of the long-term precoding W1 and the short-term precoding W2.

Preferably, the second obtaining module is specifically configured to:

existing 8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating precoding vector selection in a long-term precoding matrix; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.

Preferably, the long-term precodingWherein, theWhich contains 4 consecutive column vectors of the 8 x oversampled 4-th order DFT matrix.

Preferably, the precoding forms when the number of layers is 1 and 2 are respectively:

⊙ is a dot product operation, which means that corresponding elements of two vectors or matrixes are directly multiplied;

the above-mentionedSelected from the existing TM4 codebook of LTE

The above-mentionedRepresenting a window function, the optional window function comprising a rectangular window, a Hamming window, a Kaiser window or a Gaussian window function

The above-mentionedSelected from {1, -1, j, -j }

Preferably, theAccording to codebook index i in the TM4 codebook₂Vector of orientationConstruct its Householder transformation matrixAnd selecting the precoding matrix corresponding to the layer number v equal to 1.

Preferably, when the number of layers is 3,

or;

preferably, when the number of layers is 4,

wherein,for codebook in TM4 codebook_index＝i₂And v is 2.

Preferably, the number of layers is 5 and 6,

and

wherein,for codebook in TM4 codebook_{k index}＝i₂And v is 3.

The method and the device for constructing the multi-antenna precoding provided by the embodiment of the invention are used for obtaining the long-term precoding W1 and the short-term precoding W2, wherein the W1 is in the form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1; and acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2. The invention properly increases the feedback quantity of the short-term codebook, and utilizes a new short-term codebook construction mode to ensure that the finally constructed precoding can approach the real channel characteristic to the maximum extent, thereby effectively enhancing the performance of the existing codebook.

Drawings

Fig. 1 is a flowchart illustrating a method for constructing multi-antenna precoding according to an embodiment of the present invention;

fig. 2 is a functional block diagram of an apparatus for constructing multi-antenna precoding according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad invention. It should be further noted that, for convenience of description, only some structures, not all structures, relating to the embodiments of the present invention are shown in the drawings.

Referring to fig. 1, fig. 1 is a flowchart illustrating a method for constructing multi-antenna precoding according to an embodiment of the present invention.

As shown in fig. 1, the method for constructing multi-antenna precoding includes:

101, acquiring a long-term precoding W1 and a short-term precoding W2, wherein the W1 is in a form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

and 102, acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2.

Preferably, the obtaining of the total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2 includes:

existing 8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating long-term precoding momentsSelecting a precoding vector in the array; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.

Wherein the long-term precodingWherein, theWhich contains 4 consecutive column vectors of the 8 x oversampled 4-th order DFT matrix.

Wherein, the precoding forms when the number of layers is 1 and 2 are respectively:

⊙ is a dot product operation, which means that corresponding elements of two vectors or matrixes are directly multiplied;

the above-mentionedSelected from the existing TM4 codebook of LTE

The above-mentionedRepresenting a window function, the optional window function comprising a rectangular window, a Hamming window, a Kaiser windowOr a gaussian window function;

the above-mentionedFor selecting from {1, -1, j, -j }

Wherein, theAccording to codebook index i in the TM4 codebook₂Vector of orientationConstruct its Householder transformation matrixAnd selecting the precoding matrix corresponding to the layer number v equal to 1.

When the number of the layers is 3,

or;

when the number of layers is 4, the number of layers,

wherein,is code book index i in TM4 codebook₂When v is 2And encoding the matrix.

When the number of layers is 5 and 6,

and

wherein,is code book index i in TM4 codebook₂And v is 3.

The method for constructing the multi-antenna precoding provided by the embodiment of the invention is characterized in that a long-term precoding W1 and a short-term precoding W2 are obtained, wherein W1 is in a form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1; and acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2. The invention properly increases the feedback quantity of the short-term codebook, and utilizes a new short-term codebook construction mode to ensure that the finally constructed precoding can approach the real channel characteristic to the maximum extent, thereby effectively enhancing the performance of the existing codebook.

Referring to fig. 2, fig. 2 is a functional block diagram of an apparatus for constructing multi-antenna precoding according to an embodiment of the present invention.

As shown in fig. 2, the apparatus for constructing multi-antenna precoding includes:

a first obtaining module 201, configured to obtain a long-term precoding W1 and a short-term precoding W2, where W1 is in the form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

a second obtaining module 202, configured to obtain a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, where the total precoding matrix W is a product of the long-term precoding W1 and the short-term precoding W2.

Preferably, the second obtaining module 202 is specifically configured to:

existing 8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating precoding vector selection in a long-term precoding matrix; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.

Preferably, the long-term precodingWherein, theWhich contains 4 consecutive column vectors of the 8 x oversampled 4-th order DFT matrix.

Preferably, the precoding forms when the number of layers is 1 and 2 are respectively:

⊙ is a dot product operation, which means that corresponding elements of two vectors or matrixes are directly multiplied;

the above-mentionedSelected from the existing TM4 codebook of LTE

The above-mentionedRepresenting a window function, the optional window function comprising a rectangular window, a hamming window, a kaiser window or a gaussian window function;

the above-mentionedSelected from {1, -1, j, -j }

Preferably, theAccording to codebook index i in the TM4 codebook₂Vector of orientationConstruct its Householder transformation matrixAnd selecting the precoding matrix corresponding to the layer number v equal to 1.

Preferably, when the number of layers is 3,

or;

preferably, when the number of layers is 4,

wherein,is code book index i in TM4 codebook₂And v is 2.

Preferably, the number of layers is 5 and 6,

and

wherein,is code book index i in TM4 codebook₂And v is 3.

The device for constructing the multi-antenna precoding provided by the embodiment of the invention obtains a long-term precoding W1 and a short-term precoding W2, wherein W1 is in the form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1; and acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2. The invention properly increases the feedback quantity of the short-term codebook, and utilizes a new short-term codebook construction mode to ensure that the finally constructed precoding can approach the real channel characteristic to the maximum extent, thereby effectively enhancing the performance of the existing codebook.

The technical principle of the embodiment of the present invention is described above in conjunction with the specific embodiments. The description is only intended to explain the principles of embodiments of the invention and should not be taken in any way as limiting the scope of the embodiments of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive step, and these embodiments will fall within the scope of the present invention.

Claims (10)

1. A method of constructing multi-antenna precoding, the method comprising:

acquiring long-term precoding W1 and short-term precoding W2, wherein the W1 is in a form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete Fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

and acquiring a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, wherein the total precoding matrix W is the product of the long-term precoding W1 and the short-term precoding W2.

2. The method of claim 1, wherein the obtaining of the total precoding matrix W from the long-term precoding W1 and the short-term precoding W2 comprises:

existing 8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating precoding vector selection in a long-term precoding matrix; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.

3. The method of claim 2, wherein the long-term precoding is based on a precoding matrix of the mobile stationWherein, theWhich contains 4 consecutive column vectors of the 8 x oversampled 4-th order DFT matrix.

4. The method of claim 2, wherein the precoding patterns when the number of layers is 1 and 2 are respectively:

⊙ is a dot product operation, which means that corresponding elements of two vectors or matrixes are directly multiplied;

the above-mentionedSelected from the existing TM4 codebook of LTE

The above-mentionedRepresenting a window function, the optional window function comprising a rectangular window, a hamming window, a kaiser window or a gaussian window function;

the above-mentionedFor selecting from {1, -1, j, -j }

5. The method of claim 4, wherein the step of determining the target position is performed by a computerAccording to codebook i of the TM4₂Vector of orientationConstruct its Householder transformation matrixAnd selecting the precoding matrix corresponding to the layer number v equal to 1.

6. The method of claim 2, wherein when the number of layers is 3,

or;

7. the method of claim 2, wherein when the number of layers is 4,

wherein,is code book index i in TM4 codebook₂And v is 2.

8. The method of claim 2, wherein when the number of layers is 5 and 6,

and

wherein,is code book index i in TM4 codebook₂And v is 3.

9. An apparatus for constructing multi-antenna precoding, the apparatus comprising:

a first obtaining module, configured to obtain a long-term precoding W1 and a short-term precoding W2, where W1 is in the form of a block diagonal matrix, and diagonal elements are composed of partial column vectors in an oversampled discrete fourier transform matrix; the W2 is used to linearly combine vectors contained in the W1;

a second obtaining module, configured to obtain a total precoding matrix W according to the long-term precoding W1 and the short-term precoding W2, where the total precoding matrix W is a product of the long-term precoding W1 and the short-term precoding W2.

10. The apparatus of claim 9, wherein the second obtaining module is specifically configured to:

existing 8-antenna 1-6 layer total precoding matrixWherein RI denotes the number of layers of the precoding, i₁For indicating precoding vector selection in a long-term precoding matrix; i is described₂The linear combination parameter is used for indicating the linear combination parameters among 4 long-term precoding vectors in a long-term precoding matrix; i is described₃The window function type is used for indicating the window function type adopted when 4 long-term precoding vectors are linearly combined; i is described₄For indicating the phase adjustment factor between the two antenna polarization direction precodes.