WO2017088118A1

WO2017088118A1 - Precoding method and apparatus in multiple-input multiple-output transmission mode

Info

Publication number: WO2017088118A1
Application number: PCT/CN2015/095506
Authority: WO
Inventors: 王珏平; 苏豫新; 蒲涛; 申正照
Original assignee: 华为技术有限公司
Priority date: 2015-11-25
Filing date: 2015-11-25
Publication date: 2017-06-01
Also published as: CN108292939A

Abstract

Provided are a precoding method and apparatus in a multiple-input multiple-output transmission mode, which relate to the technical field of communications and can reduce the calculation load of a baseband in a precoding process. The solution comprises: acquiring channel state information (CSI) between each UE of N UEs and M antennas; performing a cluster division according to the CSI between each UE and the M antennas to obtain Z clusters, Z single-cluster-related UE groups belonging to a single-cluster, and Y multi-cluster-related UEs belonging to a multi-cluster; establishing a single-cluster-related matrix and a multi-cluster-related matrix, wherein the single-cluster-related matrix includes a CSI correlation between the Z single-cluster-related UE groups and the Z clusters, the multi-cluster-related matrix induces a CSI correlation between the Y multi-cluster-related UEs and the Z clusters, and the single-cluster-related matrix is a block diagonal matrix; and determining a precoding matrix according to the single-cluster-related matrix and the multi-cluster-related matrix so as to perform precoding processing according to the precoding matrix.

Description

Precoding method and device in multiple input multiple output transmission mode

Technical field

The embodiments of the present invention relate to the field of communications technologies, and in particular, to a precoding method and apparatus in a multiple input multiple output transmission mode.

Background technique

MIMO (Multiple-Input Multiple-Output) transmission mode refers to the use of multiple transmit and receive antennas at the transmitter and receiver, respectively, so that signals are transmitted and received through multiple antennas at the transmitting end and the receiving end, thereby improving Communication quality.

As shown in FIG. 1 , in the MIMO transmission mode, a BBU (Base Band Unit) or a BBU Group (hereinafter collectively referred to as a BBU) can jointly perform all user data streams by using a zero-forcing algorithm by precoding. Pre-processing, after passing through RRU (Remote Radio Unit), ANT (antenna, receiving antenna) and transmission channel, reduce interference between transmission signals of different transmitting antennas.

The zero-forcing algorithm will cause the baseband calculation amount to increase by 3 times with the increase of the number of antennas. Therefore, in order to reduce the calculation amount of the baseband in the above precoding process, it can be in several base stations (ie, one base station group, as shown in FIG. 2). In the coverage area, the plurality of base stations are divided into clusters according to the distribution of the UE. As shown in FIG. 2, 16 base stations in the area 1 can be divided into four clusters (ie, C1, C2). , C3 and C4), at this time, UE1 belongs to C1, UE2 belongs to C2, UE3 belongs to C3, and UE4 and UE5 belong to C4, so that MIMO transmission can be performed between base stations inside each cluster.

However, for UEs at two or more cluster edges (ie, multi-cluster related UEs), such as UE5, since CSI (Channel State Information) between UE5 and C2 and C3 is large, UE5 is When C4 performs MIMO transmission internally, it will be affected by inter-cluster interference generated by C2 and C3.

Summary of the invention

Embodiments of the present invention provide a precoding side in a multiple input multiple output transmission mode The method and the device can reduce the calculation amount of the baseband in the precoding process, and reduce the inter-cluster interference of the UE located at the cluster edge.

In order to achieve the above object, embodiments of the present invention adopt the following technical solutions:

In a first aspect, an embodiment of the present invention provides a precoding method in a multiple input multiple output (MIMO) transmission mode, where the MIMO transmission mode includes M antennas and N UEs, where M>0, N>0, The method includes: acquiring channel state information CSI between each of the N UEs and the M antennas; performing clustering according to CSI between each UE and the M antennas to obtain Z clusters and belonging to a single a group of Z single-cluster related UEs of the cluster and Y multi-cluster related UEs belonging to the cluster, the single cluster related UE group being a set of single cluster related UEs belonging to the same cluster, Z>0, N≥Y≥0; a single cluster correlation matrix and a multi-cluster correlation matrix, the single cluster correlation matrix comprising a correspondence relationship between the Z single-cluster related UE groups and the C clusters, the multi-cluster correlation matrix including the Y multi-cluster related UEs Corresponding relationship between the C clusters, the single cluster correlation matrix is a block diagonal matrix; determining a precoding matrix according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to perform precoding according to the precoding matrix deal with.

It can be seen that since the single cluster correlation matrix A is a block diagonal matrix, the calculation of the baseband in the precoding process can be significantly reduced when calculating the pseudo inverse matrix of the single cluster correlation matrix A, and at the same time, since this scheme is only The precoding matrix is determined by the method of cluster division, and MIMO transmission is not performed separately in each cluster, so inter-cluster interference at the cluster edge UE can be avoided.

With reference to the first aspect, in a first possible implementation manner of the first aspect, the CSI includes an intensity indication RSSI of the received signal, where the clustering is performed according to the RSSI between the UE and the M antennas, Obtaining Z clusters, Z single cluster related UE groups belonging to a single cluster, and Y multi-cluster related UEs belonging to multiple clusters, including: dividing the area covered by the M antennas into Z clusters, each cluster includes At least one antenna; if an RSSI between the first UE and at least one antenna in the first cluster is greater than or equal to a first threshold, and an RSSI between each antenna in other clusters other than the first cluster is less than a first threshold And determining, that the first UE is a single-cluster related UE that belongs to the first cluster, where the first UE is any one of the N UEs, and the first cluster is any one of the Z clusters; With the Z Determining, by the first UE, a multi-cluster related UE belonging to the multi-cluster, determining that the RSSI between the antennas in the at least two clusters is greater than or equal to the first threshold; determining Z of the N UEs belonging to the single cluster A single cluster related UE group, and Y multi-cluster related UEs belonging to multiple clusters, wherein each single cluster related UE group includes at least one single cluster related UE belonging to a single cluster.

The first threshold may be dynamically adjusted according to actual performance effects. In this way, the Z single-cluster related UE groups belonging to the single cluster among the N UEs can be determined by using the foregoing method, and determining which single or cluster-related UEs are included in each single-cluster related UE group, and Y belonging to the multi-cluster Multiple clusters of related UEs.

In conjunction with the first possible implementation of the first aspect, in a second possible implementation manner of the first aspect, determining Z single-cluster related UE groups belonging to a single cluster among the N UEs, and belonging to multiple clusters After the Y multi-cluster related UEs, the method further includes: if the number Y of the multi-cluster related UEs is greater than a second threshold, adjusting the first threshold to a third threshold, where the third threshold is greater than the first threshold; Determining the number of the multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.

In conjunction with the first possible implementation of the first aspect, in a third possible implementation manner of the first aspect, determining Z single-cluster related UE groups belonging to a single cluster among the N UEs, and belonging to multiple clusters After the Y multi-cluster related UEs, the method further includes: if the number Y of the multi-cluster related UEs is greater than the second threshold, re-dividing the area covered by the M antennas into J clusters, each cluster including at least An antenna, J≠Z, J>0; determining the number of multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.

It can be seen that, in the foregoing method for adjusting the number of related UEs Y, in order to reduce the computational complexity of the BBU as much as possible, the number Y of the multi-cluster related UEs can be limited to be less than or equal to the second threshold, so that more singles can be obtained. Cluster related UE.

In combination with the first aspect and any one of the first to third possible implementation manners of the first aspect, in a fourth possible implementation manner of the first aspect, establishing a single cluster correlation matrix and a multi-cluster correlation Matrix, including: establishing a single cluster correlation matrix A,

Where a _{i,i is} used to indicate CSI between the single-cluster related UE in the i-th single-cluster related UE group and the antenna in the i-th cluster, Z≥i≥1; establish a multi-cluster correlation matrix B,

Wherein b _{Y, Z is} used to indicate CSI between the Yth multi-cluster related UE and the antenna in the Zth cluster.

It can be seen that the above-mentioned single-cluster correlation matrix A is a block diagonal matrix, and at the same time, since the number Y of multi-cluster related UEs is controlled, a multi-cluster correlation matrix B having a relatively low dimension can also be obtained, and therefore, in subsequent calculations When the single cluster correlation matrix A and the pseudo inverse matrix are used, the computational complexity can be greatly reduced.

With reference to the first aspect, and any one of the first to fourth possible implementation manners of the first aspect, in the fifth possible implementation manner of the first aspect, according to the single cluster correlation matrix and the multiple The cluster correlation matrix determines a precoding matrix to facilitate precoding processing according to the precoding matrix, including: calculating a pseudo inverse matrix of the single cluster correlation matrix; and an order recursive algorithm by a pseudo inverse matrix, according to the single cluster correlation matrix The pseudo inverse matrix and the multi-cluster correlation matrix B calculate a pseudo inverse matrix of the channel state information matrix C; the precoding matrix is determined according to the pseudo inverse matrix of the channel state information matrix C.

It can be seen that the pseudo-inverse calculation of the single-cluster correlation matrix A (ie, the block diagonal matrix) can be obtained by respectively obtaining the inverse matrix of the auto-correlation matrix of the block diagonal, which can greatly reduce the pseudo-inverse of the single-cluster correlation matrix A. The amount of computation calculated.

With reference to the first aspect, and any one of the first to the fifth possible implementation manners of the first aspect, in a sixth possible implementation manner of the first aspect, acquiring each of the N UEs The CSI between the M antennas includes: acquiring pilot information between each of the N UEs and the M antennas; and according to the pilot information between the UE and the M antennas, The CSI between the UE and the M antennas is calculated separately.

In a second aspect, an embodiment of the present invention provides a precoding apparatus in a multiple input multiple output (MIMO) transmission mode, where the MIMO transmission mode includes M antennas and N UEs, where M>0, N>0, The device includes: an acquiring unit, configured to acquire channel state information CSI between each of the N UEs and the M antennas; and a cluster dividing unit, configured to use, according to each of the UEs and the M antennas The CSI performs clustering to obtain Z clusters, Z single cluster related UE groups belonging to a single cluster, and Y multi-cluster related UEs belonging to multiple clusters, and the single cluster related UE group is a single cluster related UE belonging to the same cluster. a set of Z>0, N≥Y≥0; establishing unit for establishing a single cluster correlation matrix and a multi-cluster correlation matrix, the single cluster correlation matrix comprising the Z single cluster related UE groups and the Z a correspondence between the CSIs of the clusters, the multi-cluster correlation matrix comprising the correspondence between the C clusters of the Y multi-cluster related UEs and the Z clusters, the single cluster correlation matrix being a block diagonal matrix; a coding unit, configured to determine a precoding matrix according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to be based on the pre Code matrix for precoding processing.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the CSI includes an intensity indication RSSI of the received signal, where the cluster division unit is specifically configured to: the area covered by the M antennas Divided into Z clusters, each cluster including at least one antenna; if the RSSI between the first UE and at least one antenna in the first cluster is greater than or equal to a first threshold, and other clusters except the first cluster And determining, by the first UE, a single-cluster related UE that belongs to the first cluster, where the first UE is any one of the N UEs, and the first cluster is the Z Any one of the clusters; if the RSSI between the first UE and each antenna in at least two of the Z clusters is greater than or equal to the first threshold, determining that the first UE is a multi-cluster correlation belonging to multiple clusters Determining, by the UE, Z single-cluster related UE groups belonging to a single cluster, and Y multi-cluster related UEs belonging to multiple clusters, each single cluster related UE group including at least one single cluster related belonging to a single cluster UE.

With reference to the first possible implementation manner of the second aspect, in a second possible implementation manner of the second aspect, the cluster dividing unit is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold And adjusting the first threshold to a third threshold, where the third threshold is greater than the first threshold; redetermining the number of multi-cluster related UEs in the N UEs, until The number Y of the multi-cluster related UEs is less than or equal to the second threshold.

With reference to the first possible implementation of the second aspect, in a third possible implementation manner of the second aspect, the cluster dividing unit is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold And re-dividing the area covered by the M antennas into J clusters, each cluster including at least one antenna, J≠Z, J>0; determining the number of multi-cluster related UEs in the N UEs until The number Y of the multi-cluster related UEs is less than or equal to the second threshold.

With reference to the second aspect, and any one of the first to third possible implementation manners of the second aspect, in a fourth possible implementation manner of the second aspect, the establishing unit is specifically configured to establish a single Cluster correlation matrix A,

With reference to the second aspect, and any one of the first to the fourth possible implementation manners of the second aspect, in a fifth possible implementation manner of the second aspect, the pre-coding unit is specifically used for calculating a pseudo-inverse matrix of the single-cluster correlation matrix; a pseudo-inverse matrix of the pseudo-inverse matrix, a pseudo-inverse matrix of the channel-state information matrix C according to the pseudo-inverse matrix of the single-cluster correlation matrix and the multi-cluster correlation matrix B,

The precoding matrix is determined according to a pseudo inverse matrix of the channel state information matrix C.

With reference to the second aspect, and any one of the first to fifth possible implementation manners of the second aspect, in a sixth possible implementation manner of the second aspect, the acquiring unit further includes a computing module, where The acquiring unit is specifically configured to acquire pilot information between each of the N UEs and the M antennas; the calculating module is used for rooting According to the pilot information between each UE and the M antennas, the received CSI between each UE and the M antennas is calculated respectively.

In a third aspect, an embodiment of the present invention provides a precoding apparatus in a multiple input multiple output (MIMO) transmission mode, including: a processor, a memory, a bus, and an interface circuit;

The memory is configured to store a computer execution instruction, the processor is connected to the memory through the bus, and when the precoding device in the MIMO transmission mode is running, the processor executes the computer execution instruction stored in the memory to enable the MIMO The precoding apparatus in the transmission mode performs the precoding method in the MIMO transmission mode as in any of the above first aspects.

So far, an embodiment of the present invention provides a precoding apparatus in a multiple input multiple output transmission mode, where M antennas and N UEs are included in the MIMO transmission mode, and M>0, N>0, then, CSI between each of the N UEs and the M antennas; further, clustering according to CSI between each UE and M antennas, obtaining Z clusters, single cluster related UE groups belonging to a single cluster, and A multi-cluster related UE belonging to multiple clusters, Z>0; and a single cluster correlation matrix A and a multi-cluster correlation matrix B are formed, the single cluster correlation matrix A containing C single cluster related UE groups and CSI between the Z clusters Corresponding relationship, the multi-cluster correlation matrix B includes a correspondence relationship between the C multi-cluster related UEs and the C clusters, wherein the single cluster correlation matrix A is a block diagonal matrix; finally, according to the single cluster The correlation matrix A and the multi-cluster correlation matrix B determine the precoding matrix to facilitate precoding processing according to the precoding matrix. It can be seen that since the single cluster correlation matrix A is a block diagonal matrix, the single cluster correlation matrix is calculated. The pseudo inverse matrix of A can significantly reduce the amount of baseband computation in the precoding process, while Since the program is merely determining a precoding matrix by the method of the divided clusters, not MIMO transmission respectively within each cluster, thereby avoiding inter-edge UE located at the cluster-cluster interference.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art description will be briefly described below.

1 is a schematic diagram of the principle of a MIMO transmission mode in the prior art;

FIG. 2 is a diagram showing a BMU performing MIMO transmission mode by cluster division in the prior art. intention;

3 is a schematic flowchart of a precoding method in a multiple input multiple output transmission mode according to an embodiment of the present invention;

4 is a schematic diagram of clustering in a multiple input multiple output transmission mode according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram 1 of a precoding apparatus in a multiple input multiple output transmission mode according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram 2 of a precoding apparatus in a multiple input multiple output transmission mode according to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of an internal base station according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of hardware of a BBU according to an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments.

In addition, the terms "first" and "second" are used for descriptive purposes only, and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include one or more of the features either explicitly or implicitly. In the description of the present invention, "a plurality" means two or more unless otherwise stated.

The application scenario in the distributed MIMO transmission system is generally as shown in FIG. 1. In a CRAN area, that is, based on Centralized Processing, Collaborative Radio's green wireless access network architecture (Clean system) The BBU performs joint precoding processing on the user data streams sent by different UEs, and after the multiple RRUs are converted into radio frequency signals, the radio frequency signals are sent on the transmission channel through multiple antennas, so that the corresponding UE receives the radio frequency signals, and finally Implement MIMO transmission mode.

In the prior art, the BBU usually uses a zero-forcing algorithm to calculate the precoding matrix when performing joint precoding processing, but the zero-forcing algorithm causes the baseband computation amount to increase with the number of antennas. The third-order level is increased. In this regard, the embodiment of the present invention provides a pre-coding method in a multiple-input multiple-output transmission mode. As shown in FIG. 3, it is assumed that the MIMO transmission mode includes M antennas and N UEs. Methods include:

101. The BBU acquires CSI between each of the N UEs and the M antennas.

102. The BBU performs clustering according to CSI between each UE and the M antennas, and obtains Z clusters, a single cluster related UE group belonging to a single cluster, and a multi-cluster related UE belonging to multiple clusters, Z>0.

103. The BBU establishes a single cluster correlation matrix and a multi-cluster correlation matrix, where the single cluster correlation matrix includes a CSI correspondence relationship between Z single-cluster related UE groups and Z clusters, and the multi-cluster correlation matrix includes Y multi-cluster related UEs. Corresponding relationship with CSI between Z clusters, the single cluster correlation matrix is a block diagonal matrix, N≥Y≥0.

104. The BBU performs a joint operation according to the single cluster correlation matrix and the multi-cluster correlation matrix to determine a precoding matrix, so as to perform precoding processing according to the precoding matrix.

In the step S101, the BBU can obtain the CSI between each of the N UEs and the M antennas, and the distribution diagram of the UE and the antenna shown in FIG. 4 is taken as an example. In this case, N=9. M=16, the BBU can separately obtain CSI between UE1 and 16 antennas, CSI between UE2 and 16 antennas, CSI between UE3 and 16 antennas, ..., CSI between UE8 and 16 antennas And CSI between UE9 and 16 antennas.

Among them, the so-called CSI is the channel attribute of the communication link. It describes the weakening factor of the signal in each transmission path, ie the value of each element in the channel matrix H, such as Scattering, fading, multipath fading or shadowing fading, power decay of Distance), information such as the Received Signal Strength Indicator (RSSI). CSI can adapt the communication system to current channel conditions, providing high reliability and high rate communication in multi-antenna systems.

Specifically, the pilot information between each of the N UEs and the M antennas may be obtained. Further, each UE and the M are respectively calculated according to pilot information between each UE and the M antennas. Channel state information h _i,j between antennas, where h _i,j is channel state information (CSI) between UEi and antenna j.

For example, in the FDD (Frequency Division Duplexing) system, the UE may determine the CSI information according to the pilot information sent by the base station, and then the UE selects the corresponding codebook information stored in advance and sends the corresponding codebook information to the base station, and the base station according to the The codebook information determines the channel state information of the downlink channel (ie, the CSI information). In the TDD (Time Division Duplexing) system, the base station can obtain the uplink information sent by the UE according to the principle of uplink and downlink reciprocity. Demodulation is performed according to SRS (Sounding Reference Signal) to obtain uplink channel state information. Due to reciprocity, the uplink channel state information can be used as downlink channel state information (ie, CSI information).

In step 102, the BBU may obtain the channel state information matrix of the N UEs according to the CSI between each UE and the M antennas in step 101, and still use the MIMO transmission mode in FIG. 4 as an example to set the channel state. The information matrix is C, then:

Channel state information matrix

Further, clustering (for example, dynamic cluster division) may be performed based on the channel state information matrix, the M antennas are divided into Z clusters, and X single-cluster related UEs belonging to a single cluster among the N UEs are determined and belong to Multi-cluster Y multi-cluster related UEs, wherein among the X single-cluster related UEs, the UEs belonging to the same cluster form a single-cluster related UE group, thereby determining a single cluster of Z single-cluster related UE groups, Z >0.

Specifically, the area covered by the M antennas may be first divided into Z clusters (the clustering method is based on the principle of minimum inter-cluster interference, which is not limited in this patent). For example, in FIG. 4, 16 antennas are divided into 4 a cluster, each cluster including at least one antenna, the size of the Z clusters may be different; further, determining which cluster of each of the N UEs belongs to (or which UEs are included in each cluster), and the UE is Single cluster related UE or multiple cluster related UEs.

Taking the first UE (the first UE is any one of the N UEs) as an example, if the first UE and the first cluster (the first cluster is any one of the Z clusters) The RSSI value is greater than or equal to the first threshold (ie, the serving cell BS of the first UE belongs to the first cluster), And the RSSI between each antenna in the other clusters except the first cluster is smaller than the first threshold, that is, the correlation between the first UE and the first cluster is better, and the correlation with other Z-1 clusters is performed. Poor, in this case, the first UE may be determined to be a single cluster related UE belonging to the first cluster.

Correspondingly, if the RSSI value between the first UE and at least one antenna in other clusters other than the first cluster is greater than or equal to the first threshold (for example, at least two clusters in the first UE and the Z clusters) The RSSI of each antenna is greater than or equal to the first threshold, that is, the correlation between the first UE and other clusters in the Z clusters is also relatively large, and then the first UE is divided into which clusters. In this case, the signals in other clusters are interfered. Therefore, it can be determined that the first UE is a multi-cluster related UE belonging to multiple clusters.

In addition, it should be noted that, for a single cluster related UE, for example, UE1 belonging to the first cluster, since the RSSI value between the UE1 and each of the other Z-1 clusters is smaller than the first threshold, it can be ignored. Channel interference between UE1 and each antenna in other M-1 clusters, that is, channel state information h _1,j between UE1 and each antenna in other M-1 clusters is considered to be equal to 0, thus, for each A single-cluster-related UE has channel state information only between antennas in the cluster to which it belongs, and channel state information between each antenna in other clusters is 0, so that the BBU operation can be reduced when the precoding matrix is subsequently determined. the amount.

Further, considering the baseband operation and processing capability in the BBU, in order to reduce the computational complexity of the BBU as much as possible, the number of multi-cluster related UEs may be limited to be less than or equal to the second threshold, so that more single-cluster correlations may be obtained. UE.

Specifically, if the number Y of the multi-cluster related UEs determined in step 102 is greater than the second threshold, the first threshold is adjusted to a third threshold (the third threshold is greater than the first threshold), and then continues. Performing the foregoing steps to determine which cluster of each of the N UEs belongs to, and the UE is a single cluster related UE or a multi-cluster related UE until a multi-cluster correlation is obtained. The number Y of UEs is less than or equal to the second threshold.

Or, in order to limit the number of multi-cluster related UEs to be less than or equal to the second threshold, the area covered by the M antennas may be further divided into J (J≠Z, J>0) clusters, that is, the clusters are changed. a size, each cluster includes at least one antenna; then, performing the above steps to determine which cluster of each of the N UEs belongs to, and the UE is a single-cluster related UE or a multi-cluster related UE until a multi-cluster related UE is obtained The number Y is less than or equal to the second threshold.

In step 103, the BBU establishes a single cluster correlation matrix A and a multi-cluster correlation matrix B, where the single cluster correlation matrix A includes a correspondence relationship between X single-cluster related UEs and C clusters, and the multi-cluster correlation matrix B includes Correspondence between C clusters of Y multi-cluster related UEs and Z clusters, wherein the single cluster correlation matrix is a block diagonal matrix, X≥0, Y≥0, X+Y=N.

Specifically, in step 102, the M antennas may be divided into Z clusters, and X single-cluster related UEs belonging to a single cluster and Y multi-cluster related UEs belonging to multiple clusters are determined. Then, X pieces may be respectively established. The relationship between the channel state information between the single cluster related UE and the Z clusters, and the relationship between the channel state information between the Y multi-cluster related UEs and the Z clusters.

Still taking the distribution diagram of the UE and the antenna in FIG. 4 as an example, N=9, M=16, and UE1 and UE2 are single-cluster related UEs in a single-cluster related UE group (ie, UE group 1) belonging to the first cluster. , UE3 and UE4 are single-cluster related UEs in a single-cluster-related UE group (ie, UE group 2) belonging to the second cluster, and UE5 and UE6 are in a single-cluster-related UE group (ie, UE group 3) belonging to the third cluster. a single cluster related UE, UE7 and UE8 are single cluster related UEs in a single cluster related UE group (ie, UE group 4) belonging to the fourth cluster, and UE5 belongs to the first cluster, the second cluster, the third cluster, and the fourth. Multi-cluster related UEs of clusters.

As shown in Table 1, the relationship between the channel state information between the four single-cluster related UE groups and the four clusters, and the relationship between the channel state information between one multi-cluster related UE and four clusters can be seen. A block diagonal matrix can be formed between single cluster related UEs. Table 1 below shows the downlink channel status information:

Table 1

Therefore, in step 103, the BBU establishes a single cluster correlation matrix A, and A is a block diagonal matrix.

Where a _i,i is a sub-matrix for indicating CSI between the i-th single-cluster related UE group and each antenna in the i-th cluster of the Z antenna clusters, the i-th single-cluster related UE group The UEs in the UE are single-cluster related UEs, that is, the CSI between the UEs and the antennas in other Z-1 clusters is 0, for example:

And, the BBU establishes a multi-cluster correlation matrix B,

Wherein, b _{Y, Z is} used to indicate CSI between the Yth multi-cluster related UE and each antenna in one of the Z clusters, for example:

Still taking the distribution diagram of the UE and the antenna in FIG. 4 as an example, at this time, according to the relationship between the channel state information between the four single-cluster related UE groups and the four clusters in Table 1, and one multi-cluster related UE With the relationship of channel state information between the four clusters, a single cluster correlation matrix A and a multi cluster correlation matrix B can be established, namely:

In this way, the channel state information matrix C can be determined by the above-described single cluster correlation matrix A and multi cluster correlation matrix B, wherein

It can be seen that the above-mentioned single-cluster correlation matrix A is a block diagonal matrix, and at the same time, since the number Y of multi-cluster related UEs is controlled, a multi-cluster correlation matrix B having a relatively low dimension can also be obtained. In the above example, Y= 1, therefore, calculate the single cluster correlation matrix A and the subsequent BBU When the pseudo inverse matrix is used, the computational complexity can be greatly reduced.

In step 104, the BBU performs a joint operation according to the single cluster correlation matrix A and the multi-cluster correlation matrix B to obtain a pseudo inverse matrix of the channel state information matrix C required in the MIMO transmission mode, and further, the BBU is pseudo-inverse according to C. The matrix may determine a precoding matrix to be precoded to facilitate precoding processing according to the precoding matrix.

Specifically, the BBU calculates a pseudo inverse matrix of the single cluster correlation matrix A, and further calculates channel state information according to the pseudo inverse matrix of the single cluster correlation matrix A and the multi cluster related matrix B by an order recursive algorithm of the pseudo inverse matrix The pseudo inverse matrix of the matrix C, and further, the precoding matrix is determined to perform precoding processing according to the pseudo inverse matrix of the channel state information matrix C.

Illustratively, the pseudo inverse matrix of the single cluster correlation matrix A can be calculated by the following formula:

because

So A=blkiag(a _1,1 , a _2,2 ,...a _K,K );

So A ^H =blkiag(a _1,1 ^H , a _2,2 ^H ,...a _K,K ^H );

Therefore A*A ^H =blkiag(a _1,1 *a _1,1 ^H ,a _2,2 *a _2,2 ^H ,...a _K,K *a _K,K ^H );

And because the inverse matrix of A's autocorrelation matrix is:

therefore,

Further, according to the pseudo inverse matrix formula: A ⁺ = A ^H (A*A ^H ) ^-1 (where A ⁺ is the pseudo inverse matrix of A), A ⁺ = A ^H (A*A ^H ) ^-1 can be obtained. =A ^H (R _AA ) ^-1

It can be seen that the pseudo-inverse calculation of the single-cluster correlation matrix A (ie, the block diagonal matrix) can be obtained by respectively obtaining the inverse matrix of the autocorrelation matrix of the block diagonal matrix, which can greatly reduce the pseudo-single of the single-cluster correlation matrix A. The amount of computation for the inverse calculation.

Further, the pseudo inverse matrix of the channel state information matrix C can be calculated according to the pseudo inverse matrix of the pseudo-inverse matrix, according to the pseudo inverse matrix of the single cluster correlation matrix A (ie, A ⁺ ) and the multi-cluster correlation matrix B.

For example, the order recursion formula of the pseudo inverse matrix is as follows:

The F _m in the above recursive formula (11) is a matrix plus a column of the sash matrix form. When the channel state information matrix C is transposed, it is equivalent to F _m , that is, F _m = C ^T , F _m-1 = A ^T , when B is a single-row matrix, f _m =B ^T ; further, by the above recursion formula (11), it can be found

by

And f _{m is introduced} , since A is a block diagonal matrix, and also A ^T is also a block diagonal matrix, so here

The computational complexity is low, so it is convenient to find

Since F _m =C ^T , then

then

Thus, the pseudo inverse matrix C ^{+ of the} channel state information matrix C can be conveniently obtained.

Finally, the BBU can further determine the precoding matrix according to the pseudo inverse matrix C ^{+ of the} channel state information matrix C, and perform precoding processing.

So far, an embodiment of the present invention provides a precoding method in a MIMO transmission mode, where M antennas and N UEs are included in the MIMO transmission mode, and M>0, N>0, then, CSI between each of the N UEs and the M antennas; further, clustering according to CSI between each UE and M antennas, obtaining Z clusters, single cluster related UEs belonging to a single cluster, and belonging to Multi-cluster multi-cluster related UE, Z>0; establish a single cluster correlation matrix A and a multi-cluster correlation matrix B, and the single cluster correlation matrix A includes the correspondence between C single-cluster related UEs and CSI between the Z clusters The multi-cluster correlation matrix B includes a correspondence relationship between the C multi-cluster related UEs and the C clusters, wherein the single cluster correlation matrix A is a block diagonal matrix; finally, according to the single cluster correlation matrix A And the multi-cluster correlation matrix B determines the precoding matrix, so as to perform precoding processing according to the precoding matrix, it can be seen that since the single cluster correlation matrix A is a block diagonal matrix, the pseudo of the single cluster correlation matrix A is calculated. Inverse matrix can significantly reduce the amount of baseband calculation in the precoding process, and at the same time, due to this Text only determine a precoding matrix by a method of dividing the cluster, not MIMO transmission respectively within each cluster, thereby avoiding inter-cluster interference edge UE is located in clusters.

In addition, an embodiment of the present invention further provides a precoding apparatus in a multiple input multiple output transmission mode, where the MIMO transmission mode includes M antennas and N UEs, M>0, N>0, as shown in FIG. The device includes:

The acquiring unit 11 is configured to acquire channel state information CSI between each of the N UEs and the M antennas;

The clustering unit 12 is configured to perform clustering according to the CSI between the UE and the M antennas, to obtain Z clusters, a single cluster related UE group belonging to a single cluster, and a multi-cluster related UE belonging to multiple clusters. ,Z>0

The establishing unit 13 is configured to establish a single cluster correlation matrix and a multi-cluster correlation matrix, where the single cluster correlation matrix includes a correspondence between C single-cluster related UE groups and CSIs between the Z clusters, and the multi-cluster correlation matrix Corresponding relationship between C clusters of Y multi-cluster related UEs and the Z clusters, the single cluster correlation matrix is a block diagonal matrix, N≥Y≥0;

The precoding unit 14 is configured to determine a precoding matrix according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to perform precoding processing according to the precoding matrix.

Further, the CSI includes an intensity indication RSSI of the received signal, where

The cluster dividing unit 12 is specifically configured to: divide the area covered by the M antennas into Z clusters, each cluster includes at least one antenna; and between the first UE and at least one antenna in the first cluster The RSSI is greater than or equal to the first threshold, and the RSSI between each antenna in the other clusters other than the first cluster is smaller than the first threshold, determining that the first UE is a single cluster correlation belonging to the first cluster a UE, the first UE is any one of the N UEs, and the first cluster is any one of the Z clusters; if the first UE and the Z clusters are in at least two clusters Determining, by the first UE, that the first UE is a multi-cluster related UE that belongs to multiple clusters, and determining Z single-cluster related UE groups belonging to a single cluster of the N UEs, And Y multi-cluster related UEs belonging to multiple clusters.

Further, the cluster dividing unit 12 is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold, adjust the first threshold to a third threshold, where the third threshold is greater than Determining a first threshold; redetermining the number of multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.

Alternatively, the cluster dividing unit 12 is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold, re-divide the areas covered by the M antennas into J clusters, each The cluster includes at least one antenna, J≠Z, J>0; determining the number of multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.

Further, the establishing unit 13 is specifically configured to establish a single cluster correlation matrix A,

Where a _{i,i is} used to indicate the CSI between the single-cluster related UE in the i-th single-cluster related UE group and the antenna in the i-th cluster, Z≥i≥1; establish a multi-cluster correlation matrix B ,

Further, the precoding unit 14 is specifically configured to calculate a pseudo inverse matrix of the single cluster correlation matrix; an order recursive algorithm by a pseudo inverse matrix, a pseudo inverse matrix according to the single cluster correlation matrix, and the The multi-cluster correlation matrix B calculates a pseudo inverse matrix of the channel state information matrix C; and determines the precoding matrix according to the pseudo inverse matrix of the channel state information matrix C.

Further, as shown in FIG. 6, the obtaining unit 11 further includes a calculating module 15, wherein

The acquiring unit 11 is specifically configured to acquire pilot information between each of the N UEs and the M antennas;

The calculating module 15 is configured to separately calculate received CSI between each UE and the M antennas according to pilot information between each UE and the M antennas.

Further, FIG. 7 is a schematic structural diagram of a precoding apparatus applied to a base station in a multiple input multiple output transmission mode according to an embodiment of the present invention. The base station may specifically include a BBU 21, an RRU 22, an antenna feed subsystem 23, and a support structure 24 . The pre-coding device in the MIMO transmission mode may be the BBU 21 in FIG. 7 , and the BBU 21 and the RRU 22 may be connected through a CPRI interface; or the RRU 22 may be connected to the BBU 21 through the optical fiber.

The BBU 21 is configured to implement operation and maintenance of the entire base station, implement signaling processing, radio resource management, and implement an LTE physical layer and a MAC (Media Access Control, Media access control layer, L3 signaling, operation and maintenance and other main control functions.

The RRU 22 is configured to implement conversion between a baseband signal, an intermediate frequency signal, and a radio frequency signal, and implements demodulation of the LTE wireless received signal and modulation and power amplification of the transmitted signal.

The antenna feeder subsystem 23 may specifically include an antenna and a feeder connected to the radio frequency module of the base station, and an antenna and a feeder of a GPS (Global Positioning System) receiving card, which can be used for receiving and transmitting the wireless air interface signal.

The support structure 24, which is the support portion of the BBU 21 and the RRU 22, can be used to provide structural, power, and environmental monitoring functions.

The precoding apparatus in the multiple input multiple output transmission mode provided by the embodiment of the present invention mainly improves the BBU 21 in the internal structure of the base station, as shown in FIG. 8 , where the BBU 21 is taken as an example to introduce the MIMO transmission mode. Precoding device.

Specifically, as shown in FIG. 8, the BBU 21 includes a processor 1101 and an interface circuit 1102. Also shown in FIG. 8 is a memory 1103 and a bus 1104. The processor 1101, the interface circuit 1102, and the memory 1103 are connected by a bus 1104. Complete communication with each other.

Wherein, the processor 1101 is configured to:

Obtaining channel state information (CSI) between each of the N UEs and the M antennas through the interface circuit 1102;

Further, clustering according to CSI between each UE and the M antennas, obtaining Z clusters, a single cluster related UE group belonging to a single cluster, and a multi cluster related UE belonging to multiple clusters, Z>0;

Then, a single cluster correlation matrix and a multi-cluster correlation matrix are formed, where the single cluster correlation matrix includes a correspondence relationship between C single-cluster related UE groups and CSIs between the Z clusters, and the multi-cluster correlation matrix includes Y multiple Corresponding relationship between the cluster-related UE and the C clusters, the single cluster correlation matrix is a block diagonal matrix, N≥Y≥0;

Finally, a precoding matrix is determined according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to perform precoding processing according to the precoding matrix.

It should be noted that the processor 1101 herein may be a processor or a collective name of multiple processing elements. For example, the processor can be a central processor (Central) The processing unit (CPU) may also be an Application Specific Integrated Circuit (ASIC) or one or more integrated circuits configured to implement the embodiments of the present invention, for example: one or more microprocessors (digital Singnal processor, DSP), or one or more Field Programmable Gate Arrays (FPGAs).

The memory 1103 may be a storage device or a collective name of a plurality of storage elements, and is used to store parameters, data, and the like required for execution of executable program code. And the memory 1103 may include random access memory (RAM), and may also include non-volatile memory such as a magnetic disk memory, a flash memory, or the like.

The bus 1104 may be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus 1104 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 8, but it does not mean that there is only one bus or one type of bus.

The BBU 21 may further include an input/output device connected to the bus 1104 to be connected to other portions such as the processor 1101 via a bus. The input/output device can provide an input interface for the operator, so that the operator can select the control item through the input interface, and can also select a preset plurality of base stations. In addition, an output interface can be provided to display tracking information or results to the operator.

So far, an embodiment of the present invention provides a precoding apparatus in a multiple input multiple output transmission mode, where M antennas and N UEs are included in the MIMO transmission mode, and M>0, N>0, then, CSI between each of the N UEs and the M antennas; further, clustering according to CSI between each UE and M antennas, obtaining Z clusters, single cluster related UEs belonging to a single cluster, and belonging to Multi-cluster multi-cluster related UE, Z>0; establish a single cluster correlation matrix A and a multi-cluster correlation matrix B, and the single cluster correlation matrix A includes the correspondence between C single-cluster related UEs and CSI between the Z clusters The multi-cluster correlation matrix B includes a correspondence relationship between the C multi-cluster related UEs and the C clusters, wherein the single cluster correlation matrix A is a block diagonal matrix; finally, according to the single cluster correlation matrix A Related to multiple clusters The matrix B determines the precoding matrix so as to perform precoding processing according to the precoding matrix. It can be seen that since the single cluster correlation matrix A is a block diagonal matrix, when calculating the pseudo inverse matrix of the single cluster correlation matrix A, Significantly reduce the amount of computation of the baseband in the precoding process. At the same time, since the scheme only determines the precoding matrix by the method of cluster division, and does not perform MIMO transmission separately in each cluster, the clusters located at the cluster edge UE can be avoided. interference.

It will be clearly understood by those skilled in the art that for the convenience and brevity of the description, only the division of each functional module described above is exemplified. In practical applications, the above function assignment can be completed by different functional modules as needed. The internal structure of the device is divided into different functional modules to perform all or part of the functions described above. For the specific working process of the system, the device and the unit described above, reference may be made to the corresponding process in the foregoing method embodiments, and details are not described herein again.

In the several embodiments provided by the present application, it should be understood that the disclosed system, apparatus, and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be used. Combinations can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product stored in a storage medium. A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) or a processor to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the appended claims.

Claims

A precoding method in a MIMO transmission mode, wherein the MIMO transmission mode includes M antennas and N user equipments, M>0, N>0, and the method includes:

Obtaining channel state information CSI between each of the N UEs and the M antennas;

Performing cluster division according to CSI between each UE and the M antennas, to obtain Z clusters, Z single cluster related UE groups belonging to a single cluster, and Y multi cluster related UEs belonging to multiple clusters, The single cluster related UE group is a set of single cluster related UEs belonging to the same cluster, Z>0, N≥Y≥0;

Establishing a single cluster correlation matrix and a multi-cluster correlation matrix, where the single cluster correlation matrix includes a correspondence relationship between the Z single-cluster related UE groups and the C clusters, and the multi-cluster correlation matrix includes the Y a correspondence between CSIs of the multi-cluster related UEs and the Z clusters, where the single cluster correlation matrix is a block diagonal matrix;

Decoding a matrix according to the single cluster correlation matrix and the multi-cluster correlation matrix to facilitate precoding processing according to the precoding matrix.
The method according to claim 1, wherein the CSI includes an intensity indication RSSI of the received signal;

According to the clustering of CSI between each UE and the M antennas, Z clusters, Z single cluster related UE groups belonging to a single cluster, and Y multi-cluster related UEs belonging to multiple clusters are obtained. include:

Dividing the area covered by the M antennas into Z clusters, each cluster including at least one antenna;

Determining if an RSSI between the first UE and at least one antenna in the first cluster is greater than or equal to a first threshold, and an RSSI between each antenna in other clusters other than the first cluster is less than a first threshold The first UE is a single cluster related UE that belongs to the first cluster, the first UE is any one of the N UEs, and the first cluster is any one of the Z clusters;

If the RSSI between the first UE and each antenna in at least two of the Z clusters If the first threshold is greater than or equal to the first threshold, determining that the first UE is a multi-cluster related UE that belongs to multiple clusters;

Determining, among the N UEs, Z single-cluster related UE groups belonging to a single cluster, and Y multi-cluster related UEs belonging to multiple clusters, wherein each single cluster related UE group includes at least one single cluster belonging to a single cluster Related UE.
The method according to claim 2, further comprising: after determining the Z single-cluster related UE groups belonging to a single cluster among the N UEs, and the Y multi-cluster related UEs belonging to the multi-cluster :

And if the number Y of the multi-cluster related UEs is greater than a second threshold, adjusting the first threshold to a third threshold, where the third threshold is greater than the first threshold;

Determining the number of the multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.
The method according to claim 2, further comprising: after determining the Z single-cluster related UE groups belonging to a single cluster among the N UEs, and the Y multi-cluster related UEs belonging to the multi-cluster :

If the number Y of the multi-cluster related UEs is greater than the second threshold, the area covered by the M antennas is re-divided into J clusters, each cluster including at least one antenna, J≠Z, J>0 ;

Determining the number of the multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.
The method according to any one of claims 1 to 4, wherein the establishing a single cluster correlation matrix and a multi cluster correlation matrix comprises:

Establish a single cluster correlation matrix A,

Where a i,i is used to indicate the CSI between the single-cluster related UE in the i-th single-cluster related UE group and each antenna in the i-th cluster, Z≥i≥1;

Establish a multi-cluster correlation matrix B,

Wherein, b Y, Z is used to indicate CSI between the Yth multi-cluster related UE and each antenna in the Zth cluster.
The method according to any one of claims 1 to 5, wherein a precoding matrix is determined according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to perform precoding processing according to the precoding matrix ,include:

Calculating a pseudo inverse matrix of the single cluster correlation matrix;

Calculating a pseudo inverse matrix of the channel state information matrix C according to the pseudo inverse matrix of the pseudo-inverse matrix, according to the pseudo inverse matrix of the single cluster correlation matrix and the multi-cluster correlation matrix B,

The precoding matrix is determined according to a pseudo inverse matrix of the channel state information matrix C.
The method according to any one of claims 1-6, wherein acquiring CSI between each of the N UEs and the M antennas includes:

Obtaining pilot information between each of the N UEs and the M antennas;

And calculating, according to the pilot information between each UE and the M antennas, CSI between the UE and the M antennas.
A precoding apparatus in a MIMO transmission mode, wherein the MIMO transmission mode includes M antennas and N user equipments UE, M>0, N>0, and the apparatus includes:

An acquiring unit, configured to acquire channel state information CSI between each of the N UEs and the M antennas;

a clustering unit, configured to perform clustering according to CSI between each UE and the M antennas, to obtain Z clusters, Z single cluster related UE groups belonging to a single cluster, and Y multiple belonging to multiple clusters a cluster-related UE, the single-cluster related UE group is a set of single-cluster related UEs belonging to the same cluster, Z>0, N≥Y≥0;

Establishing a unit for establishing a single cluster correlation matrix and a multi cluster correlation matrix, the single cluster phase The off matrix includes a correspondence between CSIs of the Z single-cluster related UE groups and the Z clusters, where the multi-cluster correlation matrix includes CSI between the Y multi-cluster related UEs and the Z clusters Corresponding relationship, the single cluster correlation matrix is a block diagonal matrix;

And a precoding unit, configured to determine a precoding matrix according to the single cluster correlation matrix and the multi cluster correlation matrix, so as to perform precoding processing according to the precoding matrix.
The apparatus according to claim 8, wherein the CSI includes an intensity indication RSSI of the received signal, wherein

The cluster dividing unit is specifically configured to: divide the area covered by the M antennas into Z clusters, each cluster includes at least one antenna; and between the first UE and at least one antenna in the first cluster The RSSI is greater than or equal to the first threshold, and the RSSI between each antenna in the other clusters except the first cluster is smaller than the first threshold, determining that the first UE is a single cluster related UE belonging to the first cluster. The first UE is any one of the N UEs, and the first cluster is any one of the Z clusters; if each of the first UE and the Z clusters are in at least two clusters Determining, by the first UE, that the first UE is a multi-cluster related UE that belongs to multiple clusters; determining Z single-cluster related UE groups belonging to a single cluster among the N UEs, and Y multi-cluster related UEs belonging to multiple clusters, wherein each single cluster related UE group includes at least one single cluster related UE belonging to a single cluster.
The device of claim 9 wherein:

The clustering unit is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold, adjust the first threshold to a third threshold, where the third threshold is greater than the first threshold Determining the number of multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.
The device of claim 9 wherein:

The clustering unit is further configured to: if the number Y of the multi-cluster related UEs is greater than a second threshold, re-divide the area covered by the M antennas into J clusters, where each cluster includes at least An antenna, J≠Z, J>0; determining the number of multi-cluster related UEs in the N UEs until the number Y of the multi-cluster related UEs is less than or equal to the second threshold.
A device according to any one of claims 8-11, wherein

The establishing unit is specifically configured to establish a single cluster correlation matrix A,
Where a i,i is used to indicate CSI between the single-cluster-related UE in the i-th single-cluster related UE group and each antenna in the i-th cluster, Z≥i≥1; establishing a multi-cluster correlation matrix B,
Wherein, b Y, Z is used to indicate CSI between the Yth multi-cluster related UE and each antenna in the Zth cluster.
Apparatus according to any one of claims 8-12, wherein

The precoding unit is specifically configured to calculate a pseudo inverse matrix of the single cluster correlation matrix; an order inverse algorithm of the pseudo inverse matrix, a pseudo inverse matrix of the single cluster correlation matrix, and the multi cluster correlation matrix B, calculating a pseudo inverse matrix of the channel state information matrix C,
The precoding matrix is determined according to a pseudo inverse matrix of the channel state information matrix C.
The apparatus according to any one of claims 8 to 13, wherein the acquisition unit further comprises a calculation module, wherein

The acquiring unit is specifically configured to acquire pilot information between each of the N UEs and the M antennas;

The calculating module is configured to calculate, according to the pilot information between each UE and the M antennas, a received CSI between the UE and the M antennas.
A precoding apparatus in a multiple input multiple output MIMO transmission mode, comprising: a processor, a memory, a bus, and an interface circuit;

The memory is configured to store a computer executing instructions, the processor being coupled to the memory via the bus, the processor executing the memory stored by the processor when the precoding device in the MIMO transmission mode is running The computer executes instructions to cause the precoding apparatus in the MIMO transmission mode to perform the precoding method in the MIMO transmission mode according to any one of claims 1-7.