CN103634071B - Pre-coding matrix selection method, device and system - Google Patents

Abstract

The embodiment of the present invention discloses a method, device and system for selecting a precoding matrix. The method includes: receiving the pilot information sent by the transmitting end through the current channel; estimating the equivalent channel matrix of the current channel according to the pilot information; Effective channel matrix and each precoding matrix in the preset precoding codebook set, respectively perform inner product and modulus operation to obtain multiple modulus values; select the precoding matrix corresponding to the largest modulus value among the multiple modulus values As the target matrix; the target matrix is fed back to the sender, so that the sender can select the target matrix to precode the signal sent through the current channel. The embodiment of the invention also discloses a precoding matrix selection device and system. The purpose of the present invention is to provide a precoding matrix selection method, device and system, which can simplify the process of precoding selection, reduce the amount of calculation in the precoding selection process, and solve the problem of the large amount of calculation and operation of the precoding matrix selection method in the prior art. complicated question.

Description

A precoding matrix selection method, device and system

technical field

The present invention relates to the field of communication technology, in particular to a method, device and system for selecting a precoding matrix.

Background technique

Multiple-Input-Multiple-Output (MIMO) technology is aimed at improving the spectrum utilization rate of the system and expanding the capacity of the system. Multiple antennas or antenna arrays are used at the signal transmitting end and receiving end to transmit signals. In order to improve the performance of the system, the MIMO communication system can use the channel information to precode the signal to be sent. One of the ways is to pre-design a certain code containing a series of precoding matrices known by both the sending end and the receiving end. The codebook, the receiving end selects a precoding matrix in the codebook, and feeds back the index or indication (Precoding Matrix Indicator, PMI) of the precoding matrix to the sending end, so that the sending end uses the corresponding precoding matrix Pre-encode the information sent.

In the prior art, the capacity criterion or the right singular matrix similarity criterion is mostly used for PMI. Specifically, the former calculates the corresponding channel capacity under each codeword, and finds the codeword corresponding to the largest channel capacity. Singular Value Decomposition (SVD) is performed on the channel to find the one closest to the first column of the right singular matrix in the codebook. The disadvantage is that the SVD decomposition of the matrix is required, and the calculation amount is also large and the operation is complicated.

Contents of the invention

Embodiments of the present invention provide a method, device and system for selecting a precoding matrix, which are applicable to MIMO systems and solve the problems of large amount of calculation and complicated operation in the prior art for selecting a precoding matrix.

In a first aspect, an embodiment of the present invention provides a method for selecting a precoding matrix, including:

Receive the pilot information sent by the sender through the current channel;

estimating an equivalent channel matrix of the current channel according to the pilot information;

Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values;

Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

feeding back the target matrix to the sending end, so that the sending end selects the target matrix to precode the signal sent through the current channel.

In a first possible implementation manner, the inner product and modulo operation are respectively performed on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values , including:

Obtaining a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix;

According to the precoding matrices in the precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set;

Substituting the equivalent channel matrix, the conjugate transposition matrix, and the column vector into a calculation formula, performing inner product and modulo operations respectively, to obtain multiple modulus values.

With reference to the first aspect or the first possible implementation of the first aspect, in a second possible implementation, in each of the equivalent channel matrix and the preset precoding codebook set The precoding matrix performs inner product and modulus operation respectively to obtain a plurality of modulus values, and the calculation formula of the modulus values includes:

N _j ＝|<H ^{H H} W _j ,W _j >|,

Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements.

With reference to the first aspect or the first or second possible implementation of the first aspect, in a third possible implementation, the selection of the precoding matrix corresponding to the largest modulus among the plurality of moduli As the target matrix, specifically include:

When the pilot information is 2x2 MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix.

With reference to the first aspect or the first or second possible implementation of the first aspect, in a fourth possible implementation, the selection of the precoding matrix corresponding to the largest modulus among the plurality of moduli As the target matrix, it also specifically includes:

When the pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal.

With reference to the first aspect or the first or second possible implementation of the first aspect, in a fifth possible implementation, the selection of the precoding matrix corresponding to the largest modulus among the plurality of moduli As the target matrix, it also specifically includes:

When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, a single-column precoding matrix corresponding to a largest modulus value among the multiple moduli values is selected as the target matrix.

In the second aspect, the embodiment of the present invention also provides a device for selecting a precoding matrix, including:

a receiver, configured to receive the pilot information sent by the sending end through the current channel;

An estimation module, configured to estimate and obtain the equivalent channel matrix of the current channel according to the pilot information received by the receiver;

A calculation module, configured to perform an inner product and a modulo operation on the equivalent channel matrix obtained by the estimation module and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values;

A selection module, configured to select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values obtained by the calculation module as the target matrix;

A feedback module, configured to feed back the target matrix obtained by the selection module to the sending end, so that the sending end selects the target matrix to precode a signal sent through the current channel.

In a first possible implementation manner, the calculation module specifically includes:

a matrix unit, configured to obtain a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix obtained by the estimation module;

a column vector unit, configured to obtain, according to the precoding matrices in the precoding codebook set, a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set;

A modulus unit for substituting the equivalent channel matrix obtained by the estimation module, the conjugate transposition matrix obtained by the matrix unit, and the column vector obtained by the column vector unit into the calculation formula, and performing inner product and modulo operations respectively , to get multiple modulus values.

With reference to the second aspect or the first possible implementation manner of the second aspect, in the second possible implementation manner, the calculation formula for the calculation module to calculate the modulus value includes:

N _j ＝|<H ^{H H} W _j ,W _j >|,

Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements.

With reference to the second aspect or the first or second possible implementation of the second aspect, in a third possible implementation, the selection module is specifically configured to:

When the pilot information received by the receiver is 2x2MIMO data and the number of streams is a single stream, select the single-column precoding matrix corresponding to the largest modulus value obtained by the calculation module as the target matrix .

In combination with the second aspect or the first or second possible implementation manner of the second aspect, in a fourth possible implementation manner, the selection module is specifically further configured to:

When the pilot information received by the receiver is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value obtained by the calculation module as the target matrix ;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal.

With reference to the second aspect or the first or second possible implementation of the second aspect, in a fifth possible implementation, the selection module is further configured to:

When the pilot information received by the receiver is high-dimensional MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value obtained by the calculation module as the target matrix.

In the third aspect, the embodiment of the present invention also provides a precoding matrix selection device, including a memory and a processor communicating with the memory, wherein a program code is stored in the memory, and the program code includes computer operation instructions . The processor executes the program code for:

Receive the pilot information sent by the sender through the current channel;

estimating an equivalent channel matrix of the current channel according to the pilot information;

Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values;

Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

feeding back the target matrix to the sending end, so that the sending end selects the target matrix to precode the signal sent through the current channel.

In a first possible implementation manner, the processor executes the program code, for performing an inner product on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set respectively and modulo operation to obtain multiple modulus values, including:

Obtaining a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix;

According to the precoding matrices in the precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set;

Substituting the equivalent channel matrix, the conjugate transposition matrix, and the column vector into a calculation formula, performing inner product and modulo operations respectively, to obtain multiple modulus values.

With reference to the third aspect or the first possible implementation manner of the third aspect, in a second possible implementation manner, the calculation formula for the processor to calculate the modulus value includes:

N _j ＝|<H ^{H H} W _j ,W _j >|,

Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements.

With reference to the third aspect or the first or second possible implementation manner of the third aspect, in a third possible implementation manner, the processor executes the program code for selecting the multiple modulus values The precoding matrix corresponding to the largest modulus value in is used as the target matrix, including:

When the pilot information is 2x2 MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix.

With reference to the third aspect or the first or second possible implementation manner of the third aspect, in a fourth possible implementation manner, the processor executes the program code for selecting the multiple modulus values The precoding matrix corresponding to the largest modulus value in is used as the target matrix, including:

When the above-mentioned pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal.

With reference to the third aspect or the first or second possible implementation manner of the third aspect, in a fifth possible implementation manner, the processor executes the program code for selecting the multiple modulus values The precoding matrix corresponding to the largest modulus value in is used as the target matrix, including:

When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, a single-column precoding matrix corresponding to a largest modulus value among the multiple moduli values is selected as the target matrix.

In a fourth aspect, an embodiment of the present invention also provides a precoding matrix selection system, the system includes a receiving end and a sending end communicating with the receiving end, and the receiving end includes the precoding matrix selection system as described above device.

Implementing the embodiment of the present invention has the following beneficial effects:

In the embodiment of the present invention, the equivalent channel matrix of the current channel is obtained by estimating the received pilot information of the transmitting end, and combined with the precoding matrix in the given precoding codebook set, the equivalent channel matrix and each The modulus of the expression composed of the precoding matrix, and selecting the precoding matrix corresponding to the largest modulus value among the multiple modulus values as the target matrix can effectively simplify the process of precoding selection and reduce the amount of calculation in the precoding selection process , to solve the problems of large calculation and complicated operation in the precoding matrix selection method in the prior art.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a schematic structural diagram of a device for selecting a precoding matrix provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of an uplink multiple-input multiple-output (Up-Link Multiple-Input Multiple-Output, ULMIMO) transmission structure;

FIG. 3 is a schematic structural diagram of another precoding matrix selection device provided by an embodiment of the present invention;

FIG. 4 is a schematic flowchart of a method for selecting a precoding matrix provided by an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a system for selecting a precoding matrix provided by an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Please refer to FIG. 1, which is a schematic structural diagram of a precoding matrix selection device provided by an embodiment of the present invention. The precoding matrix selection device is suitable for the selection of a precoding matrix in a MIMO system, including: a receiver 01, an estimation module 02, calculation module 03, selection module 04 and feedback module 05, wherein:

The receiver 01 is configured to receive the pilot information sent by the sending end through the current channel;

The estimation module 02 is configured to estimate and obtain an equivalent channel matrix of the current channel according to the pilot information received by the receiver 01 .

The calculation module 03 is configured to perform an inner product and a modulo operation on the equivalent channel matrix obtained by the estimation module 02 and each precoding matrix in the preset precoding codebook set to obtain a plurality of modulus value;

The selection module 04 is configured to select the precoding matrix corresponding to the largest modulus value among the multiple modulus values obtained by the calculation module 03 as the target matrix;

The feedback module 05 is configured to feed back the target matrix obtained by the selection module 04 to the sending end, so that the sending end selects the target matrix to precode the signal sent through the current channel.

Specifically, the transmitting end of the MIMO system includes but is not limited to: a base station (NodeB) and user equipment (UserEquipment, UE), and the receiving end of the MIMO system also includes but is not limited to: a base station and user equipment. When the base station and user equipment When communicating between the two, if the base station is the transmitting end of the MIMO system, the user equipment is the receiving end of the MIMO system; if the user equipment is the transmitting end of the MIMO system, the base station is the receiving end of the MIMO system. The precoding matrix selection device provided by the embodiment of the present invention is set in the receiving end of the MIMO system. Of course, in other embodiments, the precoding matrix selection device can also be set in other receiving ends with the same function as the MIMO system. network location, which is not limited in the present invention.

In the embodiment of the present invention, the user equipment is used as the transmitting end of the MIMO system, the base station is used as the receiving end of the MIMO system, and the precoding matrix selection device is set in the base station as an example to illustrate the technical solutions of the embodiments of the present invention.

The receiver 01 is used for receiving pilot information sent by the user equipment to the precoding matrix selection device through the current channel, and the estimation module 02 is used for estimating and obtaining an equivalent channel matrix according to the received pilot information. Assuming that the current channel is an uplink channel, the pilot information is uplink pilot information.

The calculation module 03 is configured to perform an inner product operation according to the equivalent channel matrix obtained by the estimation module 02 and each precoding matrix in the preset precoding codebook set, and perform an inner product operation for each inner product The result obtained by the operation is subjected to a modulo operation to obtain a modulus value corresponding to each precoding matrix in the precoding codebook set.

Specifically, the preset precoding codebook set is a set of multiple precoding matrices known by both the transmitting end and the receiving end of the MIMO system. In the embodiment of the present invention, the base station as the receiving end of the MIMO system can select a target matrix in the precoding codebook set according to certain rules for different equivalent channel matrices, and feed back the selected target matrix to the MIMO the sending end of the system. Specifically, a corresponding index may be established for each precoding matrix in the precoding codebook set, and when the target matrix is selected, the index corresponding to the target matrix is fed back to the user equipment as the transmitting end of the MIMO system through the uplink, So that the user equipment obtains the target matrix according to the index, and weights the useful signal before sending the useful signal. This can effectively reduce the amount of information transmission and reduce the transmission pressure of the channel.

The target matrix may also be fed back to the transmitting end of the MIMO system in other ways, which will not be repeated here.

In the embodiment of the present invention, the calculation module 03 specifically calculates the modulus N _j according to the following formula:

N _j =|<H ^H HW _j ,W _j >|, where H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, and W _j represents the A column vector formed by the elements in the first column of the jth precoding matrix in the encoding codebook set, <> means that H ^{H H} W _j and W _j perform inner product operations, and ︳︱ means perform inner product operations on the results of the inner product operations modulo operation.

Therefore, the calculation module 03 will finally obtain j modulus values N _j corresponding to j precoding matrices in the precoding codebook set.

Specifically, the selection module 04 is configured to select the precoding matrix corresponding to the largest modulus N _jmax from the j modulus N _j obtained by the calculation module 03 as the target matrix.

The feedback module 05 is used to feed back the target matrix to the user equipment, specifically to feed back the index corresponding to the target matrix to the user equipment through the uplink, so that the user equipment can obtain the target matrix according to the index, and perform useful signal processing on the useful signal before sending the useful signal. weighted. Of course, the feedback module 05 may also use other methods to feed back the target matrix to the sending end, which will not be repeated here.

Further, please continue to refer to FIG. 1, the calculation module 02 specifically includes: a matrix unit 021, a column vector unit 022 and a modulo unit 023, wherein:

The matrix unit 021 is configured to obtain a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix obtained by the estimation module 01 .

The column vector unit 022 is configured to obtain a column composed of elements in the first column of the jth precoding matrix in the precoding codebook set according to the precoding matrix in the preset precoding codebook set vector.

The modulo unit 023 is configured to substitute the equivalent channel matrix obtained by the estimation module 01, the conjugate transpose matrix obtained by the matrix unit 021, and the column vector obtained by the column vector unit 022 into the calculation formula, and respectively perform Inner product and modulo operation to obtain multiple modulus values.

Specifically, the matrix unit 021 is configured to obtain a conjugate transpose matrix H ^H of the equivalent channel matrix according to the equivalent channel matrix H obtained by the estimation module 01 .

The column vector unit 022 is configured to obtain a column vector W _j composed of elements in the first column of each precoding matrix according to each precoding matrix in the preset precoding codebook set.

The modulus unit 023 is used to substitute the equivalent channel matrix H obtained by the estimation module 01, the conjugate transposition matrix H ^H obtained by the matrix unit 021, and the column vector W _j obtained by the column vector unit 022 into the calculation Formula N _j ＝|<H ^H HW _j ,W _j >|, perform the inner product operation of H ^H HW _j and W _j respectively, and perform a modulo operation on the result obtained by each inner product operation, and obtain the precoding codebook j modulus values N _j corresponding to the j precoding matrices in the set.

The selection module 04 is specifically configured to select the maximum modulus value corresponding to the j modulus values obtained by the calculation module 03 when the pilot information received by the receiver 01 is 2x2 MIMO data and the number of streams is a single stream. A single-column precoding matrix is used as the target matrix.

The selection module 04 is specifically further configured to select the one corresponding to the largest modulus value among the j modulus values obtained by the calculation module 03 when the pilot information received by the estimation module 01 is 2x2 MIMO data and the number of streams is dual streams. A precoding matrix of two columns is used as the target matrix;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal.

The selection module 04 is specifically further configured to select the largest modulus among the j modulus values obtained by the calculation module 03 when the pilot information received by the receiver 01 is high-dimensional MIMO data and the number of streams is a single stream. The single-column precoding matrix corresponding to the value is used as the target matrix.

Specifically, the device for selecting a precoding matrix provided by the embodiment of the present invention is mainly applicable to a 2x2 MIMO system.

In the 3rd Generation Partnership Project (3GPP) organization, UL MIMO is the current Universal Mobile Telecommunications System (Universal Mobile Telecommunications System, UMTS) Terrestrial Radio Access Network (Universal Terrestrial Radio Access Network, UTRAN) R11 version A job content in . UL MIMO has two transmission modes, one is single-stream transmission and the other is dual-stream transmission. The former only transmits one transport block (Transport Block, TB) in a transmission interval (Transmission Time Interval, TTI), while the latter transmits Two TBs are transmitted simultaneously within one TTI. The main purpose of introducing UL MIMO is to improve the average throughput of the cell, but at the same time, the impact of UL MIMO on user fairness and cell edge user throughput, as well as its implementation complexity and other factors must be considered. A transmission structure of UL MIMO is shown in FIG. 2 .

The mathematical model of MIMO precoding is as follows:

Taking 2x2MIMO as an example, assuming that the signals sent by the transmitter of the MIMO system are x ₁ and x ₂ respectively, and the signals received by the receiver of the MIMO system are y ₁ and y ₂ respectively, and the channel is represented by a 2*2 matrix H, then the system model Expressed as:

or Y=HX+N

When the transmitter of the MIMO system sends a single stream, the precoding process can be expressed as

or Y=HWS+N

Wherein, w ₁ and w ₂ are two elements of a single-column precoding matrix W. s ₁ is a useful signal. That is to say, a single-stream signal corresponds to a single-column precoding matrix.

When the transmitter of the MIMO system sends dual streams, the precoding process can be expressed as

or Y=HWS+N

Wherein, w ₁ , w ₂ , w ₃ and w ₄ are four elements of a two-column precoding matrix W. s ₁ and s ₂ are signals on two streams. That is to say, the dual-stream signal corresponds to two columns of precoding matrices.

Selecting an appropriate precoding matrix at the transmitting end of a MIMO system can utilize the diversity multiplexing gain in MIMO transmission to improve link performance. In UL-MIMO, a criterion for precoding selection is to maximize the receiving signal-to-noise ratio of the mainstream, and the precoding vector of the auxiliary stream is orthogonal to the mainstream precoding vector, which means that the precoding selection in UL-MIMO is A precoding vector with 2 rows and 1 column is selected.

When the pilot information received by the receiver 01 is 2x2 MIMO data and the number of streams is a single stream, the selection module 04 is used to select the maximum modulus N _jmax corresponding to the j modulus values obtained by the calculation module 03 A single-column precoding matrix is used as the target matrix.

When the pilot information received by the receiver 01 is 2x2 MIMO data and the number of streams is dual streams, the selection module 04 is used to select the maximum modulus N _jmax corresponding to the j modulus values obtained by the calculation module 02 The two-column precoding matrix is used as the target matrix. Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, and the second column of the target matrix is used for weighting the secondary stream in the dual stream. The first and second columns of the target matrix are orthogonal.

Specifically, when performing PMI selection under single-stream signal transmission for a high-dimensional channel matrix, the precoding matrix selection device provided by the embodiment of the present invention can also be used to select a precoding matrix. Because when the high-dimensional channel matrix performs single-stream transmission, the corresponding target matrix is also a single-column precoding matrix. The high-dimensional channel matrix refers to a channel matrix larger than two dimensions, such as 4x4 MIMO.

When the pilot information received by the receiver 01 is high-dimensional MIMO data and the number of streams is a single stream, the selection module 04 is also used to select the maximum modulus value from the j modulus values obtained by the calculation module 02 The single-column precoding matrix corresponding to N _jmax is the target matrix.

In the embodiment of the present invention, the equivalent channel matrix of the current channel is obtained by estimating the received pilot information of the transmitting end, and combined with the precoding matrix in the given precoding codebook set, the equivalent channel matrix and each The modulus of the expression composed of the precoding matrix, and selecting the precoding matrix corresponding to the largest modulus value among the multiple modulus values as the target matrix can effectively simplify the process of precoding selection and reduce the amount of calculation in the precoding selection process , to solve the problems of large calculation and complicated operation in the precoding matrix selection method in the prior art.

Please refer to FIG. 3 , which is a schematic structural diagram of another precoding matrix selection device provided by an embodiment of the present invention. The precoding matrix selection device is suitable for selection of a precoding matrix in a multiple-input multiple-output MIMO system, including:

A memory 002 and a processor 001 communicating with the memory 002, wherein the memory 002 stores program codes, and the program codes include computer operation instructions.

The processor 001 executes the program code for:

Receive the pilot information sent by the sender through the current channel;

estimating an equivalent channel matrix of the current channel according to the pilot information;

Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values;

Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

feeding back the target matrix to the sending end, so that the sending end selects the target matrix to precode the signal sent through the current channel.

The processor 001 executes the program code to perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values, including:

Obtaining a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix;

According to the precoding matrices in the precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set;

Substituting the equivalent channel matrix, the conjugate transposition matrix, and the column vector into a calculation formula, performing inner product and modulo operations respectively, to obtain multiple modulus values.

The calculation formula for the processor 001 to calculate the modulus value includes:

N _j ＝|<H ^{H H} W _j ,W _j >|,

Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements.

The processor 001 executes the program code, which is used to select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix, specifically including:

When the pilot information is 2x2 MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix.

The processor 001 executes the program code, which is used to select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix, specifically including:

When the pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal.

The processor 001 executes the program code, which is used to select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix, specifically including:

When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, a single-column precoding matrix corresponding to a largest modulus value among the multiple moduli values is selected as the target matrix.

That is, the processor 001 can execute the operation of the precoding matrix selection device in FIG. 1 of the present invention to realize the selection and feedback function of the target matrix.

Please refer to FIG. 4 , which is a schematic flowchart of a method for selecting a precoding matrix provided by an embodiment of the present invention. The methods include:

S101. Receive pilot information sent by a sending end through a current channel.

S102. Estimate an equivalent channel matrix of the current channel according to the pilot information.

S103. Perform inner product and modulo calculations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values.

S104. Select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix.

S105. Feed back the target matrix to the sending end, so that the sending end selects the target matrix to precode a signal sent through the current channel.

Specifically, the transmitting end of the MIMO system includes but is not limited to: a base station and user equipment, and the receiving end of the MIMO system also includes but is not limited to: a base station and user equipment. When communicating between a base station and a user equipment, if the base station is a MIMO system If the transmitting end, the user equipment is the receiving end of the MIMO system; if the user equipment is the transmitting end of the MIMO system, the base station is the receiving end of the MIMO system. The precoding matrix selection device provided by the embodiment of the present invention is set in the receiving end of the MIMO system. Of course, in other embodiments, the precoding matrix selection device can also be set in other devices that have the same function as the receiving end of the MIMO system. network location, which is not limited in the present invention.

In the embodiment of the present invention, the user equipment is used as the transmitting end of the MIMO system, the base station is used as the receiving end of the MIMO system, and the precoding matrix selection device is set in the base station as an example to illustrate the technical solutions of the embodiments of the present invention.

After the user equipment sends pilot information to the base station through the current channel, the precoding matrix selecting means estimates and obtains an equivalent channel matrix according to the received pilot information. Assuming that the current channel is an uplink channel, the pilot information is uplink pilot information.

Specifically, the preset precoding codebook set is a set of multiple precoding matrices known by both the transmitting end and the receiving end of the MIMO system. In the embodiment of the present invention, the device for selecting the precoding matrix as the receiving end of the MIMO system can select the target matrix in the precoding codebook set according to certain rules for different equivalent channel matrices, and the selected target matrix The matrix is fed back to the transmitter of the MIMO system. Specifically, a corresponding index can be established for each precoding matrix. When the target matrix is selected, the index corresponding to the target matrix is fed back to the transmitting end of the MIMO system through the uplink, so that the transmitting end of the MIMO system can obtain the target according to the index Matrix, weighting the useful signal before sending the useful signal. The target matrix may also be fed back to the transmitting end of the MIMO system in other ways, which will not be repeated here.

In the embodiment of the present invention, the precoding matrix selection device specifically calculates the modulus N _j according to the following formula:

N _j =|<H ^H HW _j ,W _j >|, where H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, and W _j represents the A column vector formed by the elements in the first column of the jth precoding matrix in the encoding codebook set, <> means that H ^{H H} W _j and W _j perform inner product operations, and ︳︱ means perform inner product operations on the results of the inner product operations modulo operation.

Therefore, the device for selecting a precoding matrix will finally obtain j modulus values N _j corresponding to j precoding matrices in the precoding codebook set.

Specifically, the S103 includes the following steps:

Step 1: Obtain the conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix;

Step 2: According to the precoding matrices in the preset precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set;

Step 3: Substituting the equivalent channel matrix, the conjugate transpose matrix and the column vector into a calculation formula, respectively performing inner product and modulo calculations to obtain multiple modulus values.

Specifically, the precoding matrix selecting device selects the precoding matrix corresponding to the largest modulus N _jmax among the j modulus N _j as the target matrix.

The S104 is specifically divided into the following three situations:

When the pilot information is 2x2MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus among the plurality of moduli as the target matrix;

When the pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and the second column of the target matrix is orthogonal;

When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, a single-column precoding matrix corresponding to a largest modulus value among the multiple moduli values is selected as the target matrix.

Specifically, the device for selecting a precoding matrix provided by the embodiment of the present invention is mainly applicable to a 2x2 MIMO system.

In the 3GPP organization, UL MIMO is a work content in the current UMTS UTRAN R11 version. UL MIMO has two transmission modes, one is single-stream transmission and the other is dual-stream transmission. The former only transmits one TB in one transmission interval TTI, and the latter transmits two TBs simultaneously in one TTI. The main purpose of introducing UL MIMO is to improve the average throughput of the cell, but at the same time, the impact of the introduction of UL MIMO on user fairness and cell edge user throughput, as well as the complexity of its implementation must be considered. Please refer to the transmission structure of a UL MIMO shown in FIG. 2 again.

The mathematical model of MIMO precoding is as follows:

Taking 2x2MIMO as an example, assuming that the signals sent by the transmitter of the MIMO system are x ₁ and x ₂ respectively, and the signals received by the receiver of the MIMO system are y ₁ and y ₂ respectively, and the channel is represented by a 2*2 matrix H, then the system model Expressed as:

or Y=HX+N

When the transmitter of the MIMO system sends a single stream, the precoding process can be expressed as

or Y=HWS+N

Wherein, w ₁ and w ₂ are two elements of a single-column precoding matrix W. s ₁ is a useful signal. That is to say, a single-stream signal corresponds to a single-column precoding matrix.

When the transmitter of the MIMO system sends dual streams, the precoding process can be expressed as

or Y=HWS+N

Wherein, w ₁ , w ₂ , w ₃ and w ₄ are four elements of a two-column precoding matrix W. s ₁ and s ₂ are signals on two streams. That is to say, the dual-stream signal corresponds to two columns of precoding matrices.

Selecting an appropriate precoding matrix at the transmitting end of a MIMO system can utilize the diversity multiplexing gain in MIMO transmission to improve link performance. In UL-MIMO, a criterion for precoding selection is to maximize the received signal-to-noise ratio of the mainstream, and the precoding vector of the auxiliary stream is orthogonal to the mainstream precoding vector, which means that the precoding selection in UL-MIMO is A precoding vector with 2 rows and 1 column is selected.

When the pilot information received by the precoding matrix selection device is 2x2 MIMO data and the number of streams is a single stream, the precoding matrix selection device selects the single row corresponding to the largest modulus N _{jmax among} the j modulus values The precoding matrix of is used as the target matrix.

When the pilot information received by the precoding matrix selection device is 2x2 MIMO data and the number of streams is dual streams, the precoding matrix selection device selects the two corresponding to the largest modulus N _{jmax among} the j modulus values The column precoding matrix is used as the target matrix. Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, and the second column of the target matrix is used for weighting the secondary stream in the dual stream. The first column of the target matrix is orthogonal to the second column of the target matrix.

Specifically, when performing PMI selection under single-stream signal transmission for a high-dimensional channel matrix, the precoding matrix selection device provided by the embodiment of the present invention can also be used to select a precoding matrix. Because when the high-dimensional channel matrix performs single-stream transmission, the corresponding target matrix is also a single-column precoding matrix. The high-dimensional channel matrix refers to a channel matrix larger than two dimensions, such as 4x4 MIMO.

When the pilot information received by the precoding matrix selection device is high-dimensional MIMO data and the number of streams is a single stream, the precoding matrix selection device is also used to select the largest modulus N among the j modulus values The single-column precoding matrix corresponding to _jmax is used as the target matrix.

After the target matrix is selected, the target matrix needs to be fed back to the user equipment. Specifically, a corresponding index can be established for each precoding matrix in the precoding codebook set, and the precoding matrix selection device only needs to use the target matrix The corresponding index is fed back to the user equipment through the uplink, so that the user equipment obtains the target matrix according to the index, and weights the useful signal before sending the useful signal. This can effectively reduce the amount of information transmission and reduce the transmission pressure of the channel.

The target matrix may also be fed back to the transmitting end of the MIMO system in other ways, which will not be repeated here.

In the embodiment of the present invention, the equivalent channel matrix of the current channel estimated according to the received pilot information of the transmitting end is combined with the precoding matrix in the given precoding codebook set to calculate the equivalent channel matrix and each A modulus of an expression composed of the precoding matrix, and selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix can effectively simplify the process of precoding selection and reduce the calculation in the precoding selection process amount, and solve the problems of large calculation and complex operation in the precoding matrix selection method in the prior art.

Please refer to FIG. 5, which is a schematic structural diagram of a precoding matrix selection system provided by the present invention, the system includes: a receiving end 10 and a transmitting end 20 communicating with the receiving end 10, wherein:

The receiving end 10 includes a precoding matrix selection device 30, the precoding matrix selection device 30 is a precoding matrix selection device as shown in Figure 1 or Figure 3, and the precoding matrix selection device 30 is used for:

Receive the pilot information sent by the sender through the current channel;

estimating an equivalent channel matrix of the current channel according to the pilot information;

Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values;

Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix;

The target matrix is fed back to the sending end, so that the sending end 20 selects the target matrix to precode the signal sent through the current channel.

In the embodiment of the present invention, the equivalent channel matrix of the current channel estimated according to the received pilot information of the transmitting end is combined with the precoding matrix in the given precoding codebook set to calculate the equivalent channel matrix and each A modulus of an expression composed of the precoding matrix, and selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix can effectively simplify the process of precoding selection and reduce the calculation in the precoding selection process amount, and solve the problems of large calculation and complex operation in the precoding matrix selection method in the prior art.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware, and the programs can be stored in a computer-readable storage medium. During execution, it may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM), and the like.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (16)

1. A method for selecting a precoding matrix, used for the selection of a precoding matrix in a multiple-input multiple-output MIMO system, is characterized in that, comprising: Receive the pilot information sent by the sender through the current channel; estimating an equivalent channel matrix of the current channel according to the pilot information; Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values; Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix; feeding back the target matrix to the sending end, so that the sending end selects the target matrix to precode a signal sent through the current channel; Wherein, the inner product and modulo operation are respectively performed on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values, specifically including: Obtaining a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix; According to the precoding matrices in the precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set; Substituting the equivalent channel matrix, the conjugate transposition matrix, and the column vector into a calculation formula, performing inner product and modulo operations respectively, to obtain multiple modulus values. 2. The method according to claim 1, wherein the inner product and the modulo operation are respectively carried out for each precoding matrix in the equivalent channel matrix and the preset precoding codebook set , to obtain a plurality of modulus values, the calculation formula of the modulus values includes: N _j ＝|<H ^{H H} W _j ,W _j >|, Wherein, N _j is the modulus value, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the j-th A column vector of elements in the first column of the precoding matrix. 3. The method according to any one of claims 1-2, wherein the selection of the precoding matrix corresponding to the largest modulus value in the plurality of modulus values as the target matrix specifically includes: When the pilot information is 2x2 MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix. 4. The method according to any one of claims 1-2, wherein the selection of the precoding matrix corresponding to the largest modulus value in the plurality of modulus values as the target matrix specifically further includes: When the pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix; Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal. 5. The method according to claim 1, wherein the step of selecting the precoding matrix corresponding to the largest modulus in the plurality of moduli as the target matrix specifically further includes: When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix. 6. A precoding matrix selection device, used for the selection of the precoding matrix in the MIMO system, is characterized in that, comprising: a receiver, configured to receive the pilot information sent by the sending end through the current channel; An estimation module, configured to estimate and obtain the equivalent channel matrix of the current channel according to the pilot information received by the receiver; A calculation module, configured to perform an inner product and a modulo operation on the equivalent channel matrix obtained by the estimation module and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values; A selection module, configured to select the precoding matrix corresponding to the largest modulus value among the plurality of modulus values obtained by the calculation module as the target matrix; A feedback module, configured to feed back the target matrix obtained by the selection module to the sending end, so that the sending end selects the target matrix to precode a signal sent through the current channel; Wherein, the calculation module specifically includes: a matrix unit, configured to obtain a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix obtained by the estimation module; a column vector unit, configured to obtain, according to the precoding matrices in the precoding codebook set, a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set; A modulus unit, for substituting the equivalent channel matrix obtained by the estimation module, the conjugate transposition matrix obtained by the matrix unit, and the column vector obtained by the column vector unit into the calculation formula, and performing inner product and modulo operations respectively , to get multiple modulus values. 7. The precoding matrix selection device according to claim 6, wherein the calculation formula for calculating the modular value by the calculation module comprises: N _j ＝|<H ^{H H} W _j ,W _j >|, Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements. 8. The precoding matrix selection device according to any one of claims 6-7, wherein the selection module is specifically used for: When the pilot information received by the receiver is 2x2MIMO data and the number of streams is a single stream, select the single-column precoding matrix corresponding to the largest modulus value obtained by the calculation module as the target matrix . 9. The precoding matrix selection device according to any one of claims 6-7, wherein the selection module is further used for: When the pilot information received by the receiver is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value obtained by the calculation module as the target matrix ; Wherein, the first column of the target matrix is used for weighting the main stream in the dual stream, the second column of the target matrix is used for weighting the auxiliary stream in the dual stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal. 10. The precoding matrix selection device according to any one of claims 6-7, wherein the selection module is further used for: When the pilot information received by the receiver is high-dimensional MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value obtained by the calculation module as the target matrix. 11. A precoding matrix selection device, suitable for multiple-input multiple-output MIMO systems, characterized in that it includes a memory and a processor communicating with the memory, wherein a program code is stored in the memory, and the program The code includes computer operating instructions, and said processor executes said program code for: Receive the pilot information sent by the sender through the current channel; estimating an equivalent channel matrix of the current channel according to the pilot information; Perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus values; Selecting the precoding matrix corresponding to the largest modulus value among the plurality of modulus values as the target matrix; feeding back the target matrix to the sending end, so that the sending end selects the target matrix to precode a signal sent through the current channel; Wherein, the processor executes the program code, which is used to perform inner product and modulo operations on the equivalent channel matrix and each precoding matrix in the preset precoding codebook set to obtain multiple modulus, including: Obtaining a conjugate transpose matrix of the equivalent channel matrix according to the equivalent channel matrix; According to the precoding matrices in the precoding codebook set, obtain a column vector composed of elements in the first column of the jth precoding matrix in the precoding codebook set; Substituting the equivalent channel matrix, the conjugate transposition matrix, and the column vector into a calculation formula, performing inner product and modulo operations respectively, to obtain multiple modulus values. 12. The precoding matrix selecting device as claimed in claim 11, characterized in that: The calculation formula for the processor to calculate the modulus value includes: N _j ＝|<H ^{H H} W _j ,W _j >|, Wherein, H represents the equivalent channel matrix, H ^H represents the conjugate transpose matrix of the equivalent channel matrix H, W _j represents the first Column vector of column elements. 13. The device for selecting a precoding matrix according to any one of claims 11-12, wherein the processor executes the program code for selecting the corresponding maximum modulus value among the plurality of modulus values. The precoding matrix is used as the target matrix, specifically including: When the pilot information is 2x2 MIMO data and the number of streams is a single stream, select a single-column precoding matrix corresponding to the largest modulus value among the multiple moduli values as the target matrix. 14. The device for selecting a precoding matrix according to any one of claims 11-12, wherein the processor executes the program code for selecting the corresponding maximum modulus value among the plurality of modulus values. The precoding matrix is used as the target matrix, specifically including: When the pilot information is 2x2MIMO data and the number of streams is dual streams, select a precoding matrix of two columns corresponding to the largest modulus value among the plurality of modulus values as the target matrix; Wherein, the first column of the target matrix is used to weight the main stream in the dual-stream, the second column of the target matrix is used to weight the secondary stream in the dual-stream, and the first column of the target matrix and The second column of the objective matrix is orthogonal. 15. The device for selecting a precoding matrix according to any one of claims 11-12, wherein the processor executes the program code for selecting the corresponding maximum modulus value among the plurality of modulus values. The precoding matrix is used as the target matrix, specifically including: When the pilot information is high-dimensional MIMO data and the number of streams is a single stream, a single-column precoding matrix corresponding to a largest modulus value among the multiple moduli values is selected as the target matrix. 16. A precoding matrix selection system, comprising a receiving end and a transmitting end communicating with the receiving end, characterized in that the receiving end includes the precoding matrix according to any one of claims 6-10 Select a device.