WO2016023410A1

WO2016023410A1 - Downlink channel precoding method and apparatus

Info

Publication number: WO2016023410A1
Application number: PCT/CN2015/084693
Authority: WO
Inventors: 李刚
Original assignee: 电信科学技术研究院
Priority date: 2014-08-14
Filing date: 2015-07-21
Publication date: 2016-02-18
Also published as: CN105337692A; CN105337692B

Abstract

The present application relates to the field of communications, and provides a downlink channel precoding method and apparatus. The downlink channel precoding method provided in an embodiment of the present application comprises: acquiring a downlink channel estimation result; determining a precoding matrix of each group of antennas according to grouping condition of antennas of a base station and the downlink channel estimation result; and precoding a downlink signal according to the precoding matrix of each group of antennas. In the downlink channel precoding method provided in the embodiment of the present application, by grouping antennas of a base station and precoding the grouped antennas of the base station in the unit of antennas, the complexity of hardware implementation is reduced when a high-performance precoding method is used in a large-scale MU-MIMO system.

Description

Downstream channel precoding method and device

The present application claims priority to Chinese Patent Application No. 2014-1039976, filed on Aug. 14, 2014, the entire disclosure of which is hereby incorporated by reference. .

Technical field

The present application relates to the field of communications, and in particular, to a downlink channel precoding method and apparatus.

Background technique

MU-MIMO (Multi User Multi Input Multi Output) system implements spatial division multiple access of users in the downlink channel by beamforming, usually using linear coding methods such as MRT (Maximum Ratio Transmitting) The method, the zero-forcing method, etc., implement precoding on the downlink signal.

The performance of a large-scale MU-MIMO system is very dependent on the size of the base station antenna, so the number of antennas is very large. Due to the large size of the base station side antenna and the large number of users, the hardware implementation of precoding becomes very complicated. Therefore, in the prior art, the downlink signal is precoded using a low complexity maximum transmission ratio method. Compared with the zero-forcing method, the maximum emission ratio method makes the system perform poorly in the high signal-to-noise ratio region. The use of the zero-forcing method for precoding in large-scale MU-MIMO systems requires the processing of complex large matrix operations, which makes its hardware implementation highly complex.

Therefore, there is a need for a new downlink channel precoding method that can improve system performance while reducing hardware implementation complexity.

Summary of the invention

The embodiment of the present application provides a downlink channel precoding method, which is applicable to a large-scale MU-MIMO system, and can improve system performance while reducing hardware implementation complexity, and is implemented by the following technical solutions: obtaining downlink channel estimation results; For the grouping situation of the base station antenna and the downlink channel estimation result, the precoding matrix of each group of antennas is determined; and the downlink signals are precoded according to the precoding matrix of each group of antennas.

In the downlink channel precoding method provided by the embodiment of the present application, the base station antenna is grouped, and the grouped base station antenna is pre-coded in units of groups, thereby reducing the use of high performance in a large-scale MU-MIMO system. The complexity of the hardware implementation of the precoding method.

Optionally, a corresponding hardware processing unit may be disposed for each group of antennas, and each hardware processing unit performs precoding processing on all downlink signals.

A corresponding hardware processing unit is provided for each group of antennas for precoding processing, and the hardware processing unit is lowered. The complexity of precoding using high performance precoding methods.

Optionally, the first downlink channel gain matrix between all antennas and the terminal of the base station may be determined; and the first downlink channel gain matrix is divided into Q second downlink channel gain matrices according to the grouping situation of the base station antenna, Each second downlink channel gain matrix corresponds to a group of antennas, where Q is the number of antenna packets; determining a precoding matrix of each group of antennas according to each second channel gain matrix to determine a precoding matrix of each group of antennas .

By obtaining the downlink channel gain matrix between all antennas and terminals of the base station and then dividing according to the grouping situation of the base station antenna, the complexity of the hardware implementation is further simplified, that is, it is no longer necessary to use special hardware to obtain the downlink channel gain between each group of antennas and the terminal. Matrix saves resources.

Optionally, the precoding matrix of each group of antennas can be determined according to the following formula:

Wherein, W _p is a precoding matrix of the p-th antenna; H _p is a second channel gain matrix between the M antennas of the p-th antenna and the K terminals,

Where h _KM represents the channel gain between the kth terminal and the Mth antenna of the pth group antenna, and p is a positive integer.

This is a precoding matrix that uses the zero-forcing method to determine the antenna. Compared to the MRT method, the zero-forcing method performs better in the precoding process.

Optionally, if the channel between the base station antenna and the terminal is a time division duplex TDD channel, the uplink channel between the base station antenna and the terminal may be measured to obtain channel state information CSI, and the downlink channel estimation result is determined according to the CSI.

When the channel between the base station antenna and the terminal is a TDD channel, when the terminal transmits data to the base station through the uplink channel, the base station actively measures the uplink channel, so that channel state information CSI can be obtained, and at this time, the reciprocity of the TDD channel can be utilized. The estimation result of the downlink channel can be obtained without waiting for the terminal to report.

Optionally, in another embodiment of the present application, if the channel between the base station antenna and the terminal is a frequency division duplex FDD channel, the downlink channel estimation result may be obtained according to the measurement result of the downlink channel fed back by the terminal.

Although the TDD channel is mostly used in the beamforming technology, it is also possible to use the FDD channel. The above technical solution provides a solution for obtaining the downlink channel estimation result in the FDD channel, that is, the measurement of the downlink channel fed back by the terminal. The result is a downlink channel estimation result.

Correspondingly, the present application also provides a downlink channel precoding apparatus, including: a channel estimation module, configured to acquire Downstream channel estimation result. The precoding matrix determining module is configured to determine a precoding matrix of the set of antennas corresponding to the base station antenna according to the grouping situation of the base station antenna and the downlink channel estimation result. The precoding module is configured to perform precoding processing on the downlink signal according to a precoding matrix of a group of antennas corresponding to the same.

A person skilled in the art may know that each functional module of the downlink channel precoding apparatus provided by the present application may be applied to a base station as a whole apparatus, and may also be dispersedly installed in a base station, so that the base station can implement the present invention. Apply for the function of the downlink channel precoding apparatus provided.

Optionally, the precoding matrix determining module is specifically configured to: determine a first downlink channel gain matrix between all antennas and terminals of the base station. According to the grouping situation of the base station antenna, the first downlink channel gain matrix is divided into Q second downlink channel gain matrices, each second downlink channel gain matrix is corresponding to a group of antennas, and Q is the number of antenna packets. The precoding matrix of the set of antennas is determined according to a second channel gain matrix corresponding to itself.

Optionally, the precoding matrix determining module determines the precoding matrix of the group of antennas according to the following formula:

Optionally, when the channel between the base station antenna and the terminal is a time division duplex TDD channel, the channel estimation module measures the uplink channel between the base station antenna and the terminal, obtains channel state information CSI, and determines a downlink channel estimation result according to the CSI.

Optionally, when the channel between the base station antenna and the terminal is a frequency division duplex FDD channel, the channel estimation module obtains a downlink channel estimation result according to the measurement result of the downlink channel fed back by the terminal.

The downlink channel precoding method and apparatus provided by the embodiments of the present application reduce the use of high performance pre-processing in a large-scale MU-MIMO system by reasonably grouping the antennas on the base station side and precoding each group of antennas. The complexity of hardware implementation when encoding methods are precoded.

DRAWINGS

1 is a flow chart of main steps of an embodiment of the present application;

2 is a flowchart of a downlink channel precoding method according to an embodiment of the present application;

FIG. 3 is a flowchart of another downlink channel precoding method according to an embodiment of the present disclosure;

4 is a schematic structural diagram of a downlink channel precoding apparatus according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a corresponding relationship between a downlink channel precoding apparatus and each group of antennas according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of another downlink channel precoding apparatus according to an embodiment of the present disclosure.

detailed description

In the embodiment of the present application, the antennas on the base station side are reasonably grouped, and then each group of antennas is precoded, thereby reducing hardware used in precoding by using a high performance precoding method in a large-scale MU-MIMO system. The complexity of the implementation.

In the embodiment of the present application, the antenna of the base station is divided into Q groups, and Q is a positive integer. Corresponding hardware processing units are disposed corresponding to each group of antennas, and each hardware processing unit performs precoding processing on downlink signals of the corresponding group of antennas.

When grouping the base station antennas, the base station antennas can be evenly grouped according to the processing capabilities of the existing hardware units. For example, there are 256 base station antennas. In the LTE (Long Term Evolution) system, the processing capability of the hardware unit is that each hardware unit can perform precoding processing on up to 8 antennas. Therefore, the base station antenna can be divided into 256/. 8=32 groups, so that the hardware unit for precoding processing in the LTE system can be directly applied to the large-scale MU-MIMO system.

The present application will be further described in detail below with reference to the accompanying drawings. The embodiments described below are only a part of the embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

As shown in FIG. 1 , the flow of the downlink channel precoding method provided by the embodiment of the present application may be implemented on a base station side, for example, by a downlink channel precoding apparatus or a similar apparatus responsible for performing precoding, or It is executed by the base station. The process mainly includes the following steps:

S101. Acquire a downlink channel estimation result. The purpose of obtaining the downlink channel estimation result is to obtain the channel gain matrix of the downlink channel between the base station antenna and the terminal included therein.

In step S101, the manner of obtaining the downlink channel estimation result is different according to the type of the channel between the base station antenna and the terminal.

There are different types of channels between the base station antenna and the terminal, and there are usually a TDD (Time Division Duplex) channel and an FDD (Frequency Division Duplex) channel. The method of obtaining the channel estimation result is different for different channels.

For example, when the channel between the base station antenna and the terminal is a TDD channel, when the terminal transmits data to the base station through the uplink channel, the base station side can actively measure the uplink channel, so that CSI (Channel State Information) can be obtained. State information), the base station can utilize the reciprocity of the TDD channel to obtain an estimation result of the downlink channel.

For another example, when the channel between the base station antenna and the terminal is an FDD channel, the base station obtains a downlink channel estimation result according to the measurement result of the downlink channel fed back by the terminal. Although the use of TDD channels is the most common in beamforming, it is also possible to use FDD channels, which ensures that channel estimation results can still be obtained when using FDD channels.

S102. Determine a precoding matrix of each group of antennas according to a grouping situation of the base station antenna and a downlink channel estimation result.

S103. Perform precoding processing on the downlink signal according to the precoding matrix of each group of antennas.

In step S102, optionally, the precoding matrix of each group of antennas may be determined by the following steps:

Determining a first downlink channel gain matrix H between all antennas of the base station and the terminal,

The first downlink channel gain matrix H is determined by the downlink channel estimation result obtained by the steps in S101.

In the above steps, by obtaining the downlink channel gain matrix between all the antennas of the base station and the terminal, and then dividing according to the grouping situation of the base station antenna, the complexity of the hardware implementation is further simplified. In the hardware for precoding each group of antennas, It is no longer necessary to use special hardware to obtain the downlink channel gain matrix between each group of antennas and terminals, saving resources.

Optionally, the precoding matrix of each group of antennas may be determined according to the following formula: W _P =H _P ^H (H _P H _P ^H ) ^-1 , where W _P is a precoding matrix of the pth antenna, and H _P is a second channel gain matrix between the p-th antenna and the user,

For each group of antennas after grouping, it is no longer necessary to calculate the large-scale matrix and inverse the large-scale matrix due to the reduced number of antennas, which reduces the complexity.

In step S103, each group of pre-coded downlink signals x _p = w _p d. Where x _p is a downlink signal after precoding processing, and d is a downlink signal before precoding processing.

In this embodiment, the antennas on the base station side are reasonably grouped, and then each group of antennas is precoded, thereby reducing hardware implementation when performing precoding using a high performance precoding method in a large-scale MU-MIMO system. The complexity.

The embodiment of the present application is described in detail with reference to FIG. 2, taking the TDD downlink channel environment as an example. In this embodiment, the base station has 256 antennas divided into 32 groups of 8 antennas each.

As shown in FIG. 2, the embodiment includes the following steps:

S201. Measure an uplink channel to obtain a CSI, so as to obtain a channel estimation result of the downlink channel, where the downlink information is included. Channel gain matrix.

S202. Determine, according to a channel estimation result of the downlink channel, a first channel gain matrix between all 256 antennas and K terminals of the base station:

S203. The H matrix is divided into 32 second downlink channel gain matrices corresponding to each group of antennas, where each second downlink channel gain matrix is represented as:

p is a positive integer between 1 and 32.

S204. Determine a precoding matrix of each group of antennas according to the following formula:

W _P =H _P ^H (H _P H _P ^H ) ^-1

Wherein, W _p is a precoding matrix of the p-th antenna; H _p is a second channel gain matrix between the 32 antennas of the p-th antenna and the K terminals. H _p ^H represents a conjugate matrix of the H _p matrix, and (H _P H _P ^H ) ^-1 represents an inverse matrix of (H _P H _P ^H ).

This formula is the implementation method of the zero-forcing method in the pre-encoding method. Compared with the traditional MRT method, the pre-encoding system has higher performance. In detail, the channel gain matrix of the first group antenna is H ₁ , the precoding matrix is W ₁ , then W ₁ =H ₁ ^H (H ₁ H ₁ ^H ) ^-1 , and so on, and W ₁ to W are respectively obtained. ₃₂ .

S205. Perform precoding processing on the downlink signal according to the precoding matrix of each group of antennas obtained in S204. Taking the first group as an example, the first group of antennas precoded the downlink signal x ₁ = W ₁ d, where W ₁ is the precoding matrix of the first group antenna, and d is the downlink signal before the base station side precoding, x ₁ The downlink signal that is precoded by the first group antenna of the base station side. After performing precoding processing for all 32 antennas, the data after precoding of all antennas of the base station is:

The pre-coded downlink signals output by the 32 antennas together constitute the pre-coded downlink signals output by the base station 256 antennas, and the calculation results of the switching matrices between the antenna groups are not necessarily required.

In this embodiment, by grouping the base station antennas and precoding each set of antennas, the complexity of hardware implementation when precoding using a high performance precoding method in a large scale MU-MIMO system is reduced. In addition, by obtaining the precoding matrix between all the antennas and the terminal, and determining the precoding matrix between each group of antennas according to the grouping result of the base station antenna, the precoding matrix between each group of antennas and the terminal is determined, which simplifies the antenna for each group. The complexity of the hardware implementation of the hardware unit that performs the precoding process.

Based on the flow shown in FIG. 1 , the embodiment of the present application is described in detail below by taking the TDD downlink channel environment as an example. In this embodiment, the base station has 256 antennas divided into 32 groups of 8 antennas each. In this embodiment, the downlink channel gain matrix between each group of antennas and the terminal is obtained by dividing the downlink channel gain matrix between all antennas and the terminal, and the unit for performing precoding processing on each group of antennas is obtained. The downlink channel gain matrix between the antenna and the terminal needs to be determined. This method simplifies the steps performed by the method and improves the efficiency of the method. This embodiment includes the following steps:

S301. Measure an uplink channel to obtain a CSI, so as to obtain a channel estimation result of the downlink channel, where the downlink channel gain matrix is included.

S302. Determine, according to channel estimation results of the downlink channel, a channel gain matrix between each group of 8 antennas and the terminal.

Where H _p is the channel gain matrix between the p-th antenna and the terminal, and p is a positive integer between 1-32.

S303. Determine a precoding matrix of each group of antennas according to a formula:

W _P =H _P ^H (H _P H _P ^H ) ^-1 .

S304. Perform precoding processing on the downlink signal according to the precoding matrix of each group of antennas obtained in S303. 32 The pre-coded downlink signals output by the groups together constitute the pre-coded vector output by the base station 256 antennas, and the calculation results of the inter-group exchange matrix are not necessarily required.

In this embodiment, in addition to grouping the base station antennas and precoding each group of antennas, the complexity of hardware implementation when using high-performance precoding methods for precoding in large-scale MU-MIMO systems is reduced. In addition, the unit that performs precoding processing on each group of antennas needs to determine the downlink channel gain matrix between the group of antennas and the terminal, which simplifies the steps performed by the method and improves the efficiency of the method.

In the above embodiment, if the precoding is performed in the FDD channel environment using the technical solution provided by the embodiment of the present application, the acquisition manner of the downlink channel estimation result should be changed on the basis of the embodiment shown in FIG. 2 or FIG. 3. That is, step S201 or S301 is different. In the FDD channel environment, the base station obtains the downlink channel estimation result by receiving the measurement result of the downlink channel fed back by the terminal.

It should be noted that those skilled in the art should be aware that, on the one hand, the packets for the base station antenna do not have to be uniformly grouped or non-uniform, and each group of antennas should be obtained or divided according to the actual grouping situation of the base station antenna. The downlink channel gain matrix between the terminals. On the other hand, those skilled in the art should also know that for determining the precoding matrix of each group of antennas, it is not necessary to use the zero forcing method in the embodiment provided by the present application, and the conventional MRT method can also be used. In the process of implementing these methods, the technical solution provided by the embodiments of the present application can also simplify the hardware implementation effect, because the channel gain matrix is also applied.

Based on the same technical concept, the embodiment of the present application further provides a precoding apparatus, which can perform the foregoing method embodiments.

As shown in FIG. 4, the precoding apparatus provided in this embodiment of the present application may include: a channel estimation module 401, configured to acquire a downlink channel estimation result; and a precoding matrix determining module 402, configured to perform grouping according to a base station antenna and a downlink channel. Assembling the result, determining a precoding matrix of the set of antennas corresponding to the self; the precoding module 403 is configured to perform precoding processing on the downlink signal according to a precoding matrix of a group of antennas corresponding to the same. Where d ₁ -d _k is the downlink signal before precoding, W _p is the precoding matrix of the pth antenna, H _p is the downlink channel gain matrix of the pth antenna and the terminal, and x _p*M is the p The downlink signal of the group M antenna after precoding.

Optionally, the precoding matrix determining module 402 is specifically configured to: determine a first downlink channel gain matrix between all antennas and terminals of the base station. According to the grouping situation of the base station antenna, the first downlink channel gain matrix is divided into Q second downlink channel gain matrices, each second downlink channel gain matrix is corresponding to a group of antennas, and Q is the number of antenna packets; The second channel gain matrix corresponding to itself determines the precoding matrix of the set of antennas.

Optionally, the precoding matrix determining module 402 determines the precoding matrix of the set of antennas according to the following formula when determining the precoding matrix:

When the channel between the base station antenna and the terminal is a time division duplex TDD channel, the channel estimation module 401 measures the uplink channel between the base station antenna and the terminal to obtain channel state information CSI, and determines a downlink channel estimation result according to the CSI.

When the channel between the base station antenna and the terminal is a frequency division duplex FDD channel, the channel estimation module 401 obtains a downlink channel estimation result according to the measurement result of the downlink channel fed back by the terminal.

5, the base station side with a total of N _T antennas, P is divided into groups, for each group of antennas, it has a pre-coding apparatus shown in FIG. 4 subjected to precoding processing, and for each of a pre In the case of an encoding device, the input signals before precoding are both d ₁ -d _k . Where x _p*M indicates that the Mth antenna of the p-th antenna is subjected to the pre-coded downlink signal.

As shown in FIG. 6, another precoding apparatus provided in this embodiment of the present application may include:

The processor 601 is configured to read a program in the memory 604 and perform the following process:

Obtaining a downlink channel estimation result by the transceiver 602; determining a precoding matrix of the group of antennas corresponding to the base station according to the grouping situation of the base station antenna and the downlink channel estimation result; and downlinking according to the precoding matrix of the group of antennas corresponding to the pair The signal is precoded. Where d ₁ -d _k is the downlink signal before precoding, W _p is the precoding matrix of the pth antenna, H _p is the downlink channel gain matrix of the pth antenna and the terminal, and x _p*M is the p The downlink signal of the group M antenna after precoding.

The transceiver 602 is configured to receive and transmit data under the control of the processor 601.

Optionally, the processor 601 is specifically configured to: determine a first downlink channel gain matrix between all antennas and terminals of the base station. According to the grouping situation of the base station antenna, the first downlink channel gain matrix is divided into Q second downlink channel gain matrices, each second downlink channel gain matrix is corresponding to a group of antennas, and Q is the number of antenna packets; The second channel gain matrix corresponding to itself determines the precoding matrix of the set of antennas.

Optionally, when determining the precoding matrix, the processor 601 determines the precoding matrix of the group of antennas according to the following formula:

When the channel between the base station antenna and the terminal is a time division duplex TDD channel, the processor 601 measures the uplink channel between the base station antenna and the terminal to obtain channel state information CSI, and determines a downlink channel estimation result according to the CSI.

When the channel between the base station antenna and the terminal is a frequency division duplex FDD channel, the processor 601 obtains a downlink channel estimation result according to the measurement result of the downlink channel fed back by the terminal.

In FIG. 6, a bus architecture (represented by bus 600), bus 600 may include any number of interconnected buses and bridges, and bus 600 will include one or more processors represented by processor 601 and memory represented by memory 604. The various circuits are linked together. The bus 600 can also link various other circuits, such as peripherals, voltage regulators, and power management circuits, as is known in the art, and therefore, will not be further described herein. Bus interface 603 provides an interface between bus 600 and transceiver 602. Transceiver 602 can be an element or a plurality of elements, such as a plurality of receivers and transmitters, providing means for communicating with various other devices on a transmission medium. Data processed by processor 601 is transmitted over wireless medium via antenna 605. Further, antenna 605 also receives the data and transmits the data to processor 601.

The processor 601 is responsible for managing the bus 600 and the usual processing, and can also provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The memory 604 can be used to store data used by the processor 601 in performing operations.

Optionally, the processor 601 may be a CPU (Central Embedded Device), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a CPLD (Complex Programmable Logic Device). , complex programmable logic devices).

The downlink channel precoding method and apparatus provided by the embodiments of the present application reduce the large-scale MU-MIMO system by reasonably grouping the antennas on the base station side and precoding each group of antennas in units of groups. The complexity of hardware implementation when using high-performance precoding methods for precoding.

Those skilled in the art will appreciate that embodiments of the present application can be provided as a method, system, or computer program product. Thus, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment in combination of software and hardware. Moreover, the application may employ one or more computers having computer usable program code embodied therein. The form of a computer program product embodied on a storage medium, including but not limited to disk storage, CD-ROM, optical storage, and the like.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block of the flowchart illustrations and/or FIG. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine for the execution of instructions for execution by a processor of a computer or other programmable data processing device. Means for implementing the functions specified in one or more of the flow or in a block or blocks of the flow chart.

The computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture comprising the instruction device. The apparatus implements the functions specified in one or more blocks of a flow or a flow and/or block diagram of the flowchart.

These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device. The instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

It will be apparent to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit and scope of the application. Thus, it is intended that the present invention cover the modifications and variations of the present invention.

Claims

A downlink channel precoding method, comprising:

Obtaining a downlink channel estimation result;

Determining a precoding matrix of each group of antennas according to a grouping situation of the base station antenna and the downlink channel estimation result;

The downlink signal is precoded according to the precoding matrix of each set of antennas.
The method according to claim 1, wherein each of the sets of antennas is provided with a corresponding hardware processing unit; and the precoding processing of the downlink signals according to the precoding matrix of each of the sets of antennas comprises:

Each hardware processing unit performs precoding processing on the downlink signals of the corresponding group of antennas.
The method according to claim 1, wherein the determining a precoding matrix of each group of antennas according to a grouping situation of the base station antenna and the downlink channel estimation result comprises:

Determining a first downlink channel gain matrix between all antennas of the base station and the terminal;

Decoding the first downlink channel gain matrix into Q second downlink channel gain matrices according to a grouping situation of the base station antenna, each second downlink channel gain matrix corresponding to a group of antennas, where Q is the number of antenna packets;

A precoding matrix for each set of antennas is determined from each of the second channel gain matrices, respectively.
The method according to claim 3, wherein said determining a precoding matrix of each group of antennas according to each of the second channel gain matrices respectively comprises:

Determine the precoding matrix for each set of antennas according to the following formula:

Wherein, W p is a precoding matrix of the p-th antenna; H p is a second channel gain matrix between the M antennas of the p-th antenna and the K terminals,
Where h KM represents the channel gain between the kth terminal and the Mth antenna of the pth group antenna, and p is a positive integer.
The method according to claim 1, wherein the channel between the base station antenna and the terminal is a time division duplex TDD channel; and the obtaining the downlink channel estimation result comprises:

The uplink channel between the base station antenna and the terminal is measured, the complete channel state information CSI is obtained, and the downlink channel estimation result is determined according to the complete CSI.
The method according to claim 1, wherein the channel between the base station antenna and the terminal is a frequency division duplex FDD channel; and the obtaining the downlink channel estimation result comprises:

Obtaining the downlink channel estimation result according to the measurement result of the downlink channel fed back by the terminal.
A downlink channel precoding apparatus includes:

a channel estimation module, configured to obtain a downlink channel estimation result;

a precoding matrix determining module, configured to determine a precoding matrix of the set of antennas corresponding to the base station according to a grouping situation of the base station antenna and the downlink channel estimation result;

And a precoding module, configured to perform precoding processing on the downlink signal according to the precoding matrix of the set of antennas corresponding to the same.
The apparatus according to claim 7, wherein the precoding matrix determining module is further configured to:

Determining a first downlink channel gain matrix between all antennas and terminals of the base station; dividing the first downlink channel gain matrix into Q second downlink channel gain matrices according to a grouping situation of the base station antenna, each second The downlink channel gain matrix corresponds to a group of antennas, and Q is the number of antenna packets; and the precoding matrix of the group of antennas is determined according to the second channel gain matrix corresponding to itself.
The apparatus according to claim 8, wherein the precoding matrix determining module is further configured to:

Determine the precoding matrix of this group of antennas according to the following formula:

Wherein, W p is a precoding matrix of the p-th antenna; H p is a second channel gain matrix between the M antennas of the p-th antenna and the K terminals,
Where h KM represents the channel gain between the kth terminal and the Mth antenna of the pth group antenna, and p is a positive integer.
The device according to claim 7, wherein the channel estimation module is further configured to:

When the channel between the base station antenna and the terminal is a time division duplex TDD channel, the uplink channel between the base station antenna and the terminal is measured to obtain channel state information CSI, and the downlink channel estimation result is determined according to the CSI.
The device according to claim 7, wherein the channel estimation module is further configured to:

When the channel between the base station antenna and the terminal is a frequency division duplex FDD channel, the downlink channel estimation result is obtained according to the measurement result of the downlink channel fed back by the terminal.