WO2017114513A1

WO2017114513A1 - Csi feedback method and device

Info

Publication number: WO2017114513A1
Application number: PCT/CN2016/113943
Authority: WO
Inventors: 陈文洪; 陈润华; 高秋彬
Original assignee: 电信科学技术研究院
Priority date: 2015-12-30
Filing date: 2016-12-30
Publication date: 2017-07-06
Also published as: CN106936486B; CN106936486A

Abstract

Provided in the embodiments of the present invention are a method and a device for CSI feedback. In the present invention, a terminal expands, according to an agreed-upon column vector arrangement mode, an initial precoding matrix set so as to obtain an expanded precoding matrix set; and performs, according to the expanded precoding matrix set, CSI measurement and feedback. Since the expanded precoding matrix set is obtained on the basis of expanding the initial precoding matrix set, the scale of the expanded precoding matrix set is greater than that of the initial precoding matrix set. Therefore, the CSI measurement and feedback performed on the basis of the expanded precoding matrix set are able to, relative to the CSI measurement and feedback performed on the basis of the initial precoding matrix set, enable the CSI that is determined and fed back by the terminal to better reflect an actual channel state, thereby lowering the chances of the difference between SINRs of multiple data streams mapped to the same codeword being too large.

Description

CSI feedback method and device

The present application claims priority to Chinese Patent Application No. 201511021278.8, entitled "CSI Feedback Method and Apparatus", filed on December 30, 2015, the entire contents of .

Technical field

The present invention relates to the field of communications technologies, and in particular, to a channel state information (CSI) feedback method and apparatus.

Background technique

Mobile and broadband have become the development direction of modern communication technology. The 3rd Generation Partnership Project (3GPP) is committed to the evolution of 3G systems as the Long Term Evolution (LTE) system, with the goal of developing 3GPP wireless access. Technology is evolving toward high data rates, low latency, and optimized packet data applications. The multi-antenna technology of the physical layer has become one of the key technologies of the current mobile communication system. The multi-antenna technology has many advantages, such as utilizing the multiplexing gain of multiple antennas to expand the throughput of the system and the like.

The LTE Rel-8 system introduces closed-loop precoding techniques to improve spectral efficiency. The closed-loop precoding technique requires that both the base station and the terminal maintain the same set of precoding matrices, called codebooks. The size of the codebook corresponding to different transmission ranks may be different from the codewords included. Here, the transmission rank is the assumption of the number of downlink transmission layers. After estimating the channel information according to the common pilot of the cell, the terminal selects a precoding matrix from the codebook according to a certain criterion. The criteria chosen may be to maximize channel capacity, maximize output signal to interference and noise ratio, and the like. The terminal feeds the index of the precoding matrix in the codebook to the base station through the uplink channel. The index is called a Precoding Matrix Indicator (PMI), and the PMI reported by the terminal can be regarded as the quantization of the channel state information. value. The base station determines a precoding matrix to be used for the terminal based on the received PMI. In addition to the PMI, the terminal also reports the transmission rank indication information (RI, Rank Indicator) corresponding to the PMI.

In the LTE system, the transmission of the downlink two codewords is supported at most, and each codeword can have its own modulation and coding mode, and an independent Hybrid Automatic Repeat ReQuest (HARQ) process is adopted. If the number of layers transmitted downstream is greater than two, one codeword can be mapped to multiple data streams (one data stream is one layer). The mapping relationship between codewords and layers is pre-agreed: if the number of layers L is even, the number of layers per codeword mapping is L/2; if the number of layers L is odd, then mapping of two codewords The number of layers is (L-1)/2 and (L+1)/2, respectively. When performing downlink precoding, the precoding vectors used in each data stream are different, so that at the receiving end, the signal to interference plus noise ratio (SINR) of each data stream is also different. the same. When performing channel quality indication (CQI) estimation, the terminal generally processes the SINR of all data streams mapped to the same codeword to obtain an equivalent SINR of the codeword, thereby calculating a CQI, for example, all corresponding After averaging the SINR of the data stream, the equivalent SINR of the codeword is obtained.

If multiple data streams mapped to the same codeword have different SINR differences due to different precoding gains, they may use the same modulation and coding scheme to cause some data streams to be modulated too high or too low, and the data stream is detected. The SINRs do not match, causing the transmission throughput of these data streams to decrease, affecting the total data transmission rate.

Summary of the invention

The present invention provides a CSI feedback method and apparatus for performing CSI feedback based on an extended precoding matrix set, improving the matching degree of CSI and channel state fed back by the terminal, thereby reducing multiple data streams mapped to the same codeword. The possibility of a SINR difference is too large.

The CSI feedback method provided by the embodiment of the present invention includes:

The terminal extends the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

The terminal performs CSI measurement according to the extended precoding matrix set;

The terminal feeds back the measured CSI to the base station.

Optionally, the terminal extends the initial precoding matrix set according to the agreed column vector arrangement manner, including:

For a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set is extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix;

For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Optionally, the initial precoding matrix set includes N subsets, each subset corresponding to one value of the transmission rank, and the number of column vectors of the initial precoding matrix in one subset is equal to the corresponding transmission rank of the subset. The value, N is an integer greater than or equal to 1.

The column vectors used in the expansion of the initial precoding matrix corresponding to the same transmission rank value are arranged in the same manner.

Optionally, in all the extended precoding matrices corresponding to an initial precoding matrix, among the column vectors of any two extended precoding matrices, a column vector mapped to one codeword in one extended precoding matrix and another extended precoding The column vectors mapped to any codeword in the matrix are different.

Optionally, if the number of column vectors of the initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.

Optionally, the terminal performs CSI measurement according to the extended precoding matrix set, including:

The terminal uses an extended precoding matrix in the extended precoding matrix set as a precoding matrix used for downlink transmission, and performs precoding matrix indication PMI, rank indication RI, and channel quality indication CQI according to the extended precoding matrix set. Measurement of one or more CSIs, wherein the PMI is an index of an extended precoding matrix in a set of extended precoding matrices.

Optionally, before the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner, the method further includes:

Determining, by the terminal, the effective precoding matrix in the initial precoding matrix set according to the effective precoding matrix indication information sent by the base station;

The terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner, including:

The terminal expands the effective precoding matrix in the initial precoding matrix set according to an agreed column vector arrangement manner.

A CSI feedback method provided by another embodiment of the present invention includes:

The base station expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

The base station receives the CSI measured and fed back by the terminal according to the extended precoding matrix set, wherein the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges the initial according to the agreed column vector arrangement manner. The precoding matrix set is extended.

Optionally, the base station expands the initial precoding matrix set according to the agreed column vector arrangement manner, including:

Optionally, the method further includes: the base station transmitting valid precoding matrix indication information to the terminal, where the effective precoding matrix indication information is used to indicate an effective precoding matrix in the initial precoding matrix set.

The terminal provided by the embodiment of the present invention includes:

An extension module, configured to expand an initial precoding matrix set according to an agreed column vector arrangement manner, to obtain an extended precoding matrix set;

a measuring module, configured to perform CSI measurement according to the extended precoding matrix set;

And a feedback module, configured to feed back the measured CSI to the base station.

Optionally, the extension module is specifically configured to: for a part of the initial precoding matrix in the initial precoding matrix set, extend the initial precoding matrix set according to an agreed column vector arrangement manner to obtain an extended precoding matrix; For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Optionally, the measuring module is specifically configured to: use an extended precoding matrix in the extended precoding matrix set as a precoding matrix used for downlink transmission, and perform a precoding matrix indication PMI according to the extended precoding matrix set, The rank indication RI and the channel quality indicate measurements of one or more CSIs in the CQI, wherein the PMI is an index of the extended precoding matrix in the set of extended precoding matrices.

The base station provided by the embodiment of the present invention includes:

a receiving module, configured to receive CSI that is measured and fed back by the terminal according to the extended precoding matrix set, where the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges according to the agreed column vector arrangement manner The initial precoding matrix set is expanded.

A terminal provided by another embodiment of the present invention includes:

Transceiver

a memory for storing computer program instructions;

a processor coupled to the memory for reading computer program instructions stored by the memory and, in response, performing the following operations:

The initial precoding matrix set is extended according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

Performing CSI measurement according to the extended precoding matrix set;

The measured CSI is fed back to the base station.

A base station provided by another embodiment of the present invention includes:

Transceiver

a memory for storing computer program instructions;

The CSI measured and fed back by the receiving terminal according to the extended precoding matrix set, wherein the extended precoding matrix according to which the terminal performs CSI measurement and feedback is that the terminal sets the initial precoding matrix according to the agreed column vector arrangement manner. Extend it.

In the embodiment of the present invention, the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set, and performs CSI measurement and feedback according to the extended precoding matrix set. Since the extended precoding matrix set is obtained by extending the initial precoding matrix set, the size of the extended precoding matrix is larger than the initial precoding matrix set, so the CSI measurement and feedback based on the extended precoding matrix set is based on Compared with the CSI measurement and feedback, the initial precoding matrix set can make the CSI determined and fed back by the terminal more reflect the actual channel state, thereby reducing the possibility that the SINR difference of multiple data streams mapped to the same codeword is too large. .

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying for inventive labor.

1 is a schematic structural diagram of a MIMO system with a single user as an example in the prior art;

2 is a schematic diagram of a transmission structure of a codebook-based precoding technology in the prior art;

3 is a schematic flowchart of a CSI feedback process implemented on a terminal side according to an embodiment of the present invention;

4 is a schematic flowchart of a CSI feedback process implemented on a base station side according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a base station according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a terminal according to an embodiment of the present invention;

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

detailed description

MIMO technology is used in LTE networks to increase system capacity and increase throughput. FIG. 1 is a structural block diagram of a MIMO system with a single user as an example. The transmitting end, such as a base station, and a receiving end, such as a terminal, have multiple antennas. At the transmitting end, the input serial code stream is converted into several parallel independent sub-code streams through a series of pre-processing (modulation, coding, weighting, mapping) and transmitted through different transmitting antennas. At the receiving end, the antenna group not less than the number of transmitting antennas is used for receiving, and the multi-channel received signal is processed in the spatial domain and the time domain by using a certain coding relationship between the estimated channel transmission characteristics and the transmitted sub-code stream, thereby Several sub-transmission sub-streams are separated and converted into serial data output. MIMO regards the channel as a number of parallel self-channels, enabling near-distance spectrum resource reuse without multiple bandwidths (multiple transmit antennas close to the same frequency and simultaneous transmission), which can theoretically greatly expand the frequency band utilization. Rate and increase the wireless transmission rate.

However, due to the correlation of the channels in the channel matrix, the increase in capacity causes the interference to increase accordingly. In order to reduce the complexity of the terminal to eliminate the influence between channels, and at the same time reduce the system overhead, the system capacity of the MIMO is maximized, which is introduced in the prior art. Precoding technology. During the physical layer processing of LTE, several main transmission modes of the physical downlink shared channel are implemented by precoding. The closed-loop precoding technique is introduced in the LTE Rel-8 system to improve the spectrum efficiency. Closed-loop precoding first requires that both the base station and the terminal maintain a set of the same precoding matrix, called a codebook. Generally, in order to reduce the feedback overhead, when designing a communication system, a plurality of precoding matrices are usually used to form a codebook (ie, a precoding matrix set). The terminal measures the downlink channel according to the cell common reference (Cell Reference Signal, CRS), and after estimating the channel information, the terminal can select the precoding matrix in the codebook based on the preset codebook, according to the prior art, for all The precoding matrix separately determines the signal energy, compares the signal energy of the precoding matrix according to some optimization criterion, and selects from the codebook to match the current channel condition most. Precoding matrix, and feedback its corresponding precoding matrix index to the base station through the uplink channel through the feedback link. This index is recorded as a Precoding Matrix Indicator (PMI). The base station can determine the precoding matrix to be used for the terminal from the received index value. When reporting the PMI, the terminal also reports a corresponding Rank Indicator (RI) and a Channel Quality Indicator (CQI), so that the base station determines the number of codewords, the number of layers, and the use of each codeword in the downlink transmission. Modulation coding method.

In codebook-based downlink MIMO transmission, different columns of codewords in the codebook correspond to different data streams, but the current codebook design does not guarantee that the received SINR of multiple data streams mapped to the same transport block is close. of. If multiple data streams mapped to the same transport block are precoded using the best codeword, and the received SINR difference between them is large, then the same modulation and coding scheme of these streams will cause the actual code rate of each data stream to be biased. High or low, which affects data transmission performance and does not achieve the expected spectral efficiency.

The embodiment of the present invention provides a downlink CSI feedback method, where a terminal may obtain an extended precoding matrix set according to different column vectors of each precoding matrix in the initial precoding matrix set, and perform CSI measurement based on the extended precoding matrix set. And feedback to avoid performance loss due to too much SINR difference between multiple data streams mapped to the same codeword.

In the embodiment of the present invention, the base station may be an evolved base station in the LTE system or its evolved system (Evolutional Node B in English, referred to as eNB or e-NodeB), a macro base station, and a micro base station (also referred to as a "small base station". ), a pico base station, an access site (Access Point in English, or AP) or a transmission site (Transmission Point in English, TP for short).

In the embodiment of the present invention, the terminal may also be referred to as a user equipment (User Equipment, referred to as UE), or may be called Terminal, mobile station (Mobile Station in English, MS for short), and mobile terminal (in English) Mobile terminal, etc., the terminal can communicate with one or more core networks via a Radio Access Network (RAN), for example, the terminal can be a mobile phone (or "cellular" phone), having The computer or the like of the mobile terminal, for example, the terminal may also be a portable, pocket, handheld, computer built-in or in-vehicle mobile device that exchanges voice and/or data with the wireless access network.

For convenience of description, the following embodiments will be described by taking a base station and a terminal as an example.

The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

FIG. 2 shows a wireless network structure currently employing a precoding technique based on a precoding matrix set mode, which is also applicable to the embodiment of the present invention. Specifically, the structure includes a base station 201 and a terminal 202, and a wireless link 203. Both the terminal 202 and the base station 201 have multiple antennas. The terminal 202 and the base station 201 are configured with the same precoding matrix set (codebook). After measuring the downlink channel and determining the precoding matrix, the terminal 202 feeds back the precoding matrix index PMI corresponding to the precoding matrix to the base station 201 through the radio link 203. The fed back CSI may include: a CQI indicating a radio communication channel quality between the base station and the terminal, a PMI indicating a preferred precoding matrix for shaping the transmission signal, and a number of useful transport layers indicating a preferred data channel of the terminal. RI, and one or more of the estimates of channel coefficients. The fed back CSI enables the base station 201 to adaptively configure a suitable transmission scheme to improve coverage, or user data transmission rate, or more accurate prediction channel quality for future transmissions to the terminal 202.

In the embodiment of the present invention, the initial precoding matrix set may be pre-arranged on the base station side and the terminal side, or the precoding matrix set may be configured by the base station to the terminal. For example, the base station may enable the terminal to obtain an initial precoding matrix according to the parameters by indicating configuration parameters of some precoding matrix sets.

If the subset constraint of the precoding matrix set is configured, the initial precoding matrix used by the base station and the terminal is obtained according to the agreed (or base station configured) initial precoding matrix set and the subset constraint condition of the precoding matrix set. of. Specifically, the terminal determines an effective precoding matrix in the initial precoding matrix set according to the effective precoding matrix indication information sent by the base station. When the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner, the terminal expands the effective precoding matrix in the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set.

For example, the base station and the terminal pre-arrange a set of initial precoding matrices of size K, and K denotes the number of initial precoding matrices in the set, and the base station indicates, by means of a bitmap, L initial precoding matrices in the initial precoding matrix set as effective pre- Encoding matrix, the initial precoding matrix set by which the terminal performs precoding matrix set expansion is composed of L effective initial precoding matrices set. The bitmap may be a binary bit sequence, the number of bits being equal to K, each bit corresponding to an initial precoding matrix in the initial precoding matrix set, and the bit value equal to 1 indicates an initial precoding matrix corresponding to the bit. Valid, a bit value of 0 indicates that the initial precoding matrix corresponding to the bit is invalid, and vice versa.

FIG. 3 is a schematic diagram of a CSI feedback process implemented by a terminal side according to an embodiment of the present disclosure. As shown in the figure, the process may include the following steps:

Step 301: The terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set.

In this step, an extension rule used for performing precoding matrix set expansion may be pre-agreed, and the extension rule may specifically include one or more column vector arrangements. The terminal may arrange the column vectors of the initial precoding matrix in the initial precoding matrix set according to the agreed one or more column vector arrangement manners to obtain an extended precoding matrix corresponding to the initial precoding matrix. One or more extended precoding matrices may be obtained based on an initial precoding matrix, that is, one or more extended precoding matrices corresponding to one initial precoding matrix. For example, if there are N types of agreed column vector arrangements (N is an integer greater than 1), N extended precoding matrices can be obtained by sorting the column vectors of an initial precoding matrix according to the column vector arrangement.

Each of the initial precoding matrices in the initial precoding matrix set can be extended using a plurality of column vector arrangements (except for the initial precoding matrix corresponding to rank=1). In a specific implementation, for a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set may be extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix; for the initial precoding matrix set For the rest of the initial precoding matrix, the partial initial precoding matrix can be used as the corresponding extended precoding matrix.

As an example, an initial precoding matrix in the initial precoding matrix set is an N×M dimensional matrix, and the matrix has M N×1 dimensional column vectors, and the agreed column vector arrangement refers to the M columns. The arrangement of the vectors. For example, assuming M=3, the convention arrangement of the three column vectors {V1 V2 V3} may include the following three types (the following numbers are indexes of column vectors): {1,2,3}{2,1,3}{3,1,2}. After the terminal rearranges an N×M-dimensional matrix in the initial precoding matrix set according to the three column vector arrangements as defined above, three extended precoding matrices can be obtained: [V1 V2 V3], [V2 V1 V3 ] and [V3 V1 V2].

The extended precoding matrices corresponding to all the initial precoding matrices constitute an extended precoding matrix set. For example, suppose the initial precoding matrix set size is L (L represents the number of initial precoding matrices in the set, L is an integer greater than or equal to 1), and the initial precoding matrices in the initial precoding matrix set each have P species (P is an integer greater than or equal to 1) The arrangement of the agreed column vectors, the size of the obtained extended precoding matrix set is L×P.

According to the number of all possible values of the rank, the initial precoding matrix set may include a corresponding number of subsets, each subset corresponding to one value of the rank, and the number of column vectors of the initial precoding matrix in one subset is equal to the sub Set the value of the corresponding rank. Where rank indicates the number of possible transport layers or the number of transport streams. For example, in the case where the system supports a maximum of 8 streams, the value of rank may include 8 possibilities, ranging from 1 to 8. In this case, the initial precoding matrix set includes 8 subsets, that is, a subset corresponding to rank=1, a subset corresponding to rank=2, a subset corresponding to rank=3, ..., and so on. For example, taking a subset corresponding to rank=3 as an example, the subset may include one or more initial precoding matrices with a number of column vectors equal to 3.

The arrangement of the column vectors used in the initial precoding matrix extension in the subset corresponding to the value of different ranks may be the same or different, and the same rank value is used in the same manner for the column vector used in the initial precoding matrix expansion. For example, the column vector arrangement used in the initial precoding matrix extension in the subset corresponding to rank=3 is different from the column vector used in the initial precoding matrix extension in the subset corresponding to rank=4, rank=3 The column vectors used in the expansion of the initial precoding matrix in the corresponding subset are arranged in the same manner.

A more specific example is that the subset corresponding to rank=3 includes two initial precoding matrices (H ₁ , H ₂ ), and the column vectors used in the expansion of the two initial precoding matrices (H ₁ , H ₂ ) There are three types of arrangement: {1,2,3}{2,1,3}{3,1,2}, where the number represents the index of the column vector, such as {2,1,3} means: the initial pre- The second column vector in the coding matrix H ₁ is used as the first column vector of the extended precoding matrix H _{1_2} obtained by the extension, and the first column vector in H ₁ is used as the second of the extended H _{1_2} . column vector, the third column vector H ₁ as obtained after a third expansion column vectors H _{1_2,} thus obtaining the corresponding ₁ H three extended precoding matrices _{_{(H 1_1, H 1_2, H}} 1_3) . Similarly, the initial precoding matrix H ₂ also obtains three extended precoding matrices (H _{2_1} , H _{2_2} , H _{2_3} ) according to the above three column vector expansion methods.

The subset corresponding to rank=4 includes three initial precoding matrices (H ₃ , H ₄ , H ₅ ), and the arrangement of the column vectors used in the expansion of the three initial precoding matrices includes three types: {1, 2, 3 , 4}{1,3,2,4}{1,4,2,3}, where the number represents the index of the column vector, and the extension is the same as before, so that three extended precodings corresponding to H ₃ can be obtained. matrix _{_{(H 3_1, H 3_2, H}} 3_3). Similarly, the initial precoding matrix H ₄ also obtains three extended precoding matrices (H _{4_1} , H _{4_2} , H _{4_3} ) according to the above three column vector expansion methods, and the initial precoding matrix H ₅ also expands according to the above three column vectors. 3 extended manner to obtain the precoding matrix _{_{(H 5_1, H 5_2, H}} 5_3).

For an initial precoding matrix with rank=N (ie, the number of column vectors is equal to N), the column vector arrangement can have N! (N! represents the factorial operation of N, N!=N×(N-1)×(N-2)×...×1). Optionally, in the embodiment of the present invention, it is considered that the agreed column vector arrangement only reflects the allocation information of different column vectors in different codewords. Therefore, the precoding column vector used for precoding the data of the same codeword is performed. The different ordering, or the precoding column vectors used by the two codewords, are equivalent arrangements. That is, in all the extended precoding matrices corresponding to an initial precoding matrix, among the column vectors of any two extended precoding matrices, the column vector mapped to one codeword in one extended precoding matrix is combined with another extended precoding matrix. The column vector mapped to any codeword is different.

For example, assume that the number of column vectors for an initial precoding matrix is three, with the first column vector mapped to the first codeword and the second and three column vectors mapped to the second codeword. In theory, there are six ways to arrange column vectors: {1,2,3}{2,1,3}{3,1,2}{1,3,2}{2,3,1}{3,2 ,1}. Since the first column vector maps to the first codeword, the second and three column vectors map to the second codeword, so for {1, 2, 3} and {1, 3, 2}, the same The column vector is mapped to the first codeword, ie the first column vector in the initial precoding matrix is mapped to the first codeword, and the column vectors mapped to the second codeword in the two arrangements are arranged Different ways, but they are the second and third column vectors in the initial precoding matrix. Therefore, {1, 2, 3} and {1, 3, 2} are regarded as equivalent arrangements. Take one in it. Similarly, {2,1,3} and {2,3,1} are equivalent, {3,1,2} and {3,2,1} are equivalent, therefore, the column vector arrangement can be Take only three of {1,2,3}{2,1,3}{3,1,2}. {1,2,3} to obtain a spreading arrangement precoding matrix and H _{1_1} extended precoding matrix H _{1_2} {2,1,3} to obtain the arrangement of an example, it can be seen, mapped to the second H _{1_1} a column vector of a codeword (a column vector whose index number is 1 in the initial precoding matrix) and a column vector mapped to the first codeword in H _{1_2} (a column vector whose index number is 2 in the initial precoding matrix) and The column vectors mapped to the second codeword are different, and the column vector mapped to the second codeword in H _{1_1} (the column vector whose index number is 2 and 3 in the initial precoding matrix) is mapped to the first in H _{1_2} The column vectors of the second and second codewords are all different; similarly, for any other two extended precoding matrices, the law is also met.

As another example, assume that the number of column vectors for an initial precoding matrix is four, with the first two column vectors mapped to the first codeword and the last two column vectors mapped to the second codeword. For the column vector arrangement of {1, 2, 3, 4} and {4, 3, 2, 1}, the column vector {1 in the precoding matrix corresponding to {1, 2, 3, 4}, 2} is mapped to the first codeword, and the column vector {2, 1} mapped to the second codeword in the precoding matrix corresponding to {4, 3, 2, 1} is the same, so the two column vectors The arrangement is equivalent, and the two can be used.

As an example, Table 1 shows the arrangement of column vectors for rank under different values.

Table 1

In actual use, in order to prevent the extended precoding matrix set from being too large, only the partial column vector arrangement listed above may be adopted as the agreed column vector arrangement. For example, if the number of column vectors of an initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.

For example, when the value of the set threshold is 4, for the initial precoding matrix whose column vector number (ie, the value of the rank) is less than or equal to 4, the calculation of the extended precoding matrix may be performed by using the column vector arrangement in Table 1. For an initial precoding matrix with a column vector number greater than 4, only the first column vector arrangement in Table 1 is used to calculate the extended precoding matrix, that is, the column vector does not need to be reordered at this time, and the initial precoding is directly adopted. The matrix acts as an extended precoding matrix.

The initial codebook of the partial Rank may be extended only, and the initial codebooks of the other Ranks are not extended and directly used as the extended codebook. For example, the initial codebook in which a Rank is within a certain range may be extended according to the above rules to obtain a spreading codebook, and the extended codebooks of other Ranks are initial codebooks.

Step 302: The terminal performs CSI measurement according to the extended precoding matrix set.

In this step, the terminal may use the extended precoding matrix in the extended precoding matrix set as a precoding matrix used for downlink transmission, and perform measurement of one or more CSIs in PMI, RI, and CQI according to the extended precoding matrix set. Wherein, the PMI is an index of the extended precoding matrix in the extended precoding matrix set. That is, the terminal may be based on an extended precoding matrix in the extended precoding matrix set It is a hypothesis of the precoding matrix used for downlink transmission, and CSI measurement is performed.

The method for performing CSI measurement by the terminal according to the extended precoding matrix set may refer to a method for performing CSI measurement according to the initial precoding matrix. For example, after estimating the channel information according to the common pilot of the cell, the terminal may select an extended precoding matrix from the extended precoding matrix set according to a certain criterion. The criteria chosen may be to maximize interchannel capacity or maximize output signal to interference and noise ratio.

Step 303: The terminal feeds back the measured CSI to the base station.

In this step, the CSI fed back by the terminal to the base station may include one or a combination of a PMI, a Rank Indication (RI), and a CQI. The PMI reported by the terminal is an index of the corresponding precoding matrix in the extended precoding matrix set. As an example, the terminal calculates the channel capacity corresponding to each extended precoding matrix in the extended precoding matrix set, and reports the index corresponding to the extended precoding matrix with the largest channel capacity as the PMI to the base station, and simultaneously the RI corresponding to the extended precoding matrix. And CQI is also reported to the base station.

Since in the field of wireless communication, CSI is the channel attribute of the communication link, the degenerative factor of the signal on each transmission path, that is, the value of each element in the channel gain matrix H, such as signal scattering, environmental degradation, is described ( Fading, multipath fading or shadowing fading), information such as power decay of distance. CSI can adapt the communication system to current channel conditions, providing high reliability and high rate communication in multi-antenna systems. In the embodiment of the present invention, the terminal may obtain the CSI by using an extended precoding matrix determined from the extended precoding matrix set and an arrangement manner of the data transmission layer corresponding to the precoding matrix.

As can be seen from the above description, the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set, and performs CSI measurement and feedback according to the extended precoding matrix set. Since the extended precoding matrix set is obtained by extending the initial precoding matrix set, the size of the extended precoding matrix is larger than the initial precoding matrix set, so the CSI measurement and feedback based on the extended precoding matrix set is based on Compared with the CSI measurement and feedback, the initial precoding matrix set can make the CSI determined and fed back by the terminal more reflect the actual channel state, thereby reducing the possibility that the SINR difference of multiple data streams mapped to the same codeword is too large. .

Referring to FIG. 4, the CSI feedback process implemented by the base station side according to the implementation of the present invention may include the following steps:

Step 401: The base station expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set.

The base station expands the initial precoding matrix set according to the agreed column vector arrangement manner, and obtains a method for extending the precoding matrix set, and the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix. The methods of collection are the same and are not repeated here.

Step 402: The base station receives the CSI measured and fed back by the terminal according to the extended precoding matrix set.

The extended precoding matrix set on which the terminal performs CSI measurement and feedback is obtained by the terminal expanding the initial precoding matrix set according to the agreed column vector arrangement manner, and the specific method is the terminal side in the foregoing embodiment. The corresponding processing in the CQI feedback process is the same and is not repeated here. The arrangement of the agreed column vectors used by the base station is the same as the arrangement of the agreed column vectors used by the terminal.

For a more clear understanding of the embodiments of the present invention, the specific implementation process of the foregoing embodiments of the present invention is described in detail by taking a specific application scenario as an example.

The base station and the terminal agree on an initial codebook (a codebook, that is, a precoding matrix set) used for CSI measurement and feedback, and the initial codebook is a pre-agreed fixed codebook, where there are Ni initials in the initial codebook of rank=i Precoding matrix, i = 1, 2, 3, 4.

The terminal expands the initial codebook based on the agreed arrangement of column vectors to obtain a spreading codebook. The column vectors of different ranks are arranged in different ways. For details, refer to the column vector arrangement corresponding to rank=1, 2, 3, and 4 in Table 1. Where rank=1 and rank=2, the initial codebook and the extended codebook are the same. When rank=3 and rank=4, the initial precoding matrix in each initial codebook can be expanded into three based on different column vector arrangements. Precoding matrix in the spreading codebook. The spread codebook size of each rank obtained based on this extension method is {N1, N2, 3×N3, 3×N4}.

The terminal performs CSI measurement based on the extended codebook, and obtains RI, PMI, and CQI, and reports them to the base station. The PMI indicates the index of the target precoding matrix in the extended codebook, and the PMI feedback signaling overhead corresponding to each RI value (1-4) can be {log2(N1), log2(N2), log2(3, respectively. ×N3), log2(3×N4)}.

The base station expands the agreed initial codebook according to the same agreed column vector arrangement to obtain the same extended codebook. After receiving the CSI reported by the terminal, the corresponding precoding matrix is found from the spreading codebook according to the PMI, and is used for precoding of the downlink transmission.

Based on the same technical concept, an embodiment of the present invention further provides a terminal.

FIG. 5 is a schematic structural diagram of a terminal according to an embodiment of the present invention, where the terminal can implement a CSI feedback process on the terminal side. As shown, the terminal may include: an expansion module 501, a measurement module 502, and a feedback module 503, where:

The expansion module 501 is configured to expand the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set.

The measuring module 502 is configured to perform CSI measurement according to the extended precoding matrix set;

The feedback module 503 is configured to feed back the measured CSI to the base station.

Optionally, the extension module 501 is specifically configured to: for a part of the initial precoding matrix in the initial precoding matrix set, extend the initial precoding matrix set according to an agreed column vector arrangement manner to obtain an extended precoding matrix; For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Optionally, the initial precoding matrix set includes N subsets, each subset corresponding to one value of the transmission rank, and the number of column vectors of the initial precoding matrix in one subset is equal to the corresponding subset of the subset. The value of the transmission rank, where N is an integer greater than or equal to 1.

Optionally, the measurement module 502 is specifically configured to: use an extended precoding matrix in the extended precoding matrix set as a precoding matrix used for downlink transmission, and perform a precoding matrix indication PMI according to the extended precoding matrix set, The rank indication RI and the channel quality indicate measurements of one or more CSIs in the CQI, wherein the PMI is an index of the extended precoding matrix in the set of extended precoding matrices.

Based on the same technical concept, an embodiment of the present invention further provides a base station.

FIG. 6 is a schematic structural diagram of a base station according to an embodiment of the present invention, where the terminal can implement a CSI feedback process on the base station side. As shown, the base station can include an expansion module 601 and a receiving module 602, where:

The expansion module 601 is configured to expand the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

The receiving module 602 is configured to receive CSI that is measured and fed back by the terminal according to the extended precoding matrix set, where the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges according to the agreed column vector manner. The initial set of precoding matrices is expanded.

Optionally, the extension module 601 is specifically configured to: for a part of the initial precoding matrix in the initial precoding matrix set, extend the initial precoding matrix set according to an agreed column vector arrangement manner to obtain an extended precoding matrix; For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Optionally, the initial precoding matrix set includes N subsets, and each subset corresponds to a transmission rank. For one value, the number of column vectors of the initial precoding matrix in one subset is equal to the value of the transmission rank corresponding to the subset, and N is an integer greater than or equal to 1.

FIG. 7 is a schematic structural diagram of a terminal according to an embodiment of the present invention, where the terminal can implement a CSI feedback process on the terminal side. As shown, the terminal can include a processor 701, a memory 702, a transceiver 703, and a bus interface.

The processor 701 is responsible for managing the bus architecture and general processing, and the memory 702 can store data used by the processor 701 in performing operations. The transceiver 703 is configured to receive and transmit data under the control of the processor 701.

The bus architecture may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 701 and various circuits of memory represented by memory 702. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. The processor 701 is responsible for managing the bus architecture and general processing, and the memory 702 can store data used by the processor 701 in performing operations.

The signal processing flow disclosed in the embodiment of the present invention may be applied to the processor 701 or implemented by the processor 701. In the implementation process, each step of the signal processing flow may be completed by an integrated logic circuit of hardware in the processor 701 or an instruction in the form of software. The processor 701 can be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, can be implemented or implemented The methods, steps, and logical block diagrams disclosed in the embodiments of the present invention are provided. A general purpose processor can be a microprocessor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The storage medium is located in the memory 702, and the processor 701 reads the information in the memory 702 and completes the steps of the signal processing flow in conjunction with its hardware.

Specifically, the processor 701 is configured to read a program in the memory 702 and perform the following process:

Performing CSI measurement according to the extended precoding matrix set;

The measured CSI is fed back to the base station by the transceiver 703.

Optionally, the processor 701 is specifically configured to: for a part of the initial precoding matrix in the initial precoding matrix set, extend the initial precoding matrix set according to an agreed column vector arrangement manner to obtain an extended precoding matrix; For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Optionally, the processor 701 is specifically configured to: expand the extended precoding matrix set The precoding matrix is used as a precoding matrix for downlink transmission, and performs measurement of one or more CSIs of a precoding matrix indicating PMI, a rank indication RI, and a channel quality indicator CQI according to the extended precoding matrix set, where The PMI is an index of the extended precoding matrix in the extended precoding matrix set.

FIG. 8 is a schematic structural diagram of a base station according to an embodiment of the present invention, where the terminal can implement a CSI feedback process on the base station side. As shown, the base station can include a processor 801, a memory 802, a transceiver 803, and a bus interface.

The processor 801 is responsible for managing the bus architecture and general processing, and the memory 802 can store data used by the processor 801 in performing operations. The transceiver 803 is configured to receive and transmit data under the control of the processor 801.

The bus architecture may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 801 and various circuits of memory represented by memory 802. The bus architecture can also link various other circuits such as peripherals, voltage regulators, and power management circuits, which are well known in the art and, therefore, will not be further described herein. The bus interface provides an interface. The processor 801 is responsible for managing the bus architecture and general processing, and the memory 802 can store data used by the processor 801 in performing operations.

The signal processing flow disclosed in the embodiment of the present invention may be applied to the processor 801 or implemented by the processor 801. In the implementation process, each step of the signal processing flow may be completed by an integrated logic circuit of hardware in the processor 801 or an instruction in the form of software. The processor 801 can be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and can implement or perform the embodiments of the present invention. Various methods, steps, and logic blocks of the disclosure. A general purpose processor can be a microprocessor or any conventional processor or the like. The steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like. The The storage medium is located in the memory 802, and the processor 801 reads the information in the memory 802 in conjunction with its hardware to complete the steps of the signal processing flow.

Specifically, the processor 801 is configured to read a program in the memory 802 and perform the following process:

Receiving, by the transceiver 803, the CSI measured and fed back by the terminal according to the extended precoding matrix set, wherein the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges according to the agreed column vector arrangement manner. The initial precoding matrix set is extended.

Optionally, the processor 801 is specifically configured to: for a part of the initial precoding matrix in the initial precoding matrix set, extend the initial precoding matrix set according to an agreed column vector arrangement manner to obtain an extended precoding matrix; For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.

Finally, in the embodiment of the present invention, by adding different column vector ordering sequences in the initial precoding matrix set, the terminal can traverse different codewords to data streams when performing CSI feedback, so that mapping to the same code is performed. The detection SINR of multiple data streams of a word is relatively close. After the base station performs modulation coding based on the CQI fed back by the terminal, the modulation coding mode of some data streams is too high or too low, and the spectrum efficiency of the transmission is improved.

The present invention has been described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (system), and computer program products according to embodiments of the invention. 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.

While the preferred embodiment of the invention has been described, it will be understood that Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and the modifications and

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

Claims

A channel state information CSI feedback method, comprising:

The terminal extends the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

The terminal performs CSI measurement according to the extended precoding matrix set;

The terminal feeds back the measured CSI to the base station.
The method according to claim 1, wherein the terminal expands the initial precoding matrix set according to an agreed arrangement of column vectors, including:

For a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set is extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix;

For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.
The method according to claim 1, wherein the initial precoding matrix set comprises N subsets, each subset corresponding to a value of a transmission rank, and the number of column vectors of an initial precoding matrix in a subset is equal to The value of the transmission rank corresponding to the subset, and N is an integer greater than or equal to 1.
The method according to claim 3, wherein the column vectors used in the expansion of the initial precoding matrix corresponding to the same transmission rank value are arranged in the same manner.
The method according to claim 1, wherein in an extended precoding matrix corresponding to an initial precoding matrix, in a column vector of any two extended precoding matrices, an extended precoding matrix is mapped to a codeword. The column vector is different from the column vector mapped to any codeword in another extended precoding matrix.
The method according to claim 1, wherein if the number of column vectors of the initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.
The method according to any one of claims 1 to 6, wherein the terminal performs CSI measurement according to the extended precoding matrix set, including:

The terminal uses an extended precoding matrix in the extended precoding matrix set as a precoding matrix used for downlink transmission, and performs precoding matrix indication PMI, rank indication RI, and channel quality indication CQI according to the extended precoding matrix set. Measurement of one or more CSIs, wherein the PMI is an index of an extended precoding matrix in a set of extended precoding matrices.
The method according to any one of claims 1 to 6, wherein before the terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner, the method further includes:

Determining, by the terminal, the effective precoding matrix in the initial precoding matrix set according to the effective precoding matrix indication information sent by the base station;

The terminal expands the initial precoding matrix set according to the agreed column vector arrangement manner, including:

The terminal expands the effective precoding matrix in the initial precoding matrix set according to an agreed column vector arrangement manner.
A channel state information CSI feedback method, comprising:

The base station expands the initial precoding matrix set according to the agreed column vector arrangement manner to obtain an extended precoding matrix set;

The base station receives the CSI measured and fed back by the terminal according to the extended precoding matrix set, wherein the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges the initial according to the agreed column vector arrangement manner. The precoding matrix set is extended.
The method according to claim 9, wherein the base station expands the initial precoding matrix set according to an agreed arrangement of column vectors, including:

For a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set is extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix;

For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.
The method according to claim 9, wherein the initial precoding matrix set comprises N subsets, each subset corresponding to a value of a transmission rank, and the number of column vectors of an initial precoding matrix in a subset is equal to The value of the transmission rank corresponding to the subset, and N is an integer greater than or equal to 1.
The method according to claim 11, wherein the column vectors used in the expansion of the initial precoding matrix corresponding to the same transmission rank value are arranged in the same manner.
The method according to claim 9, wherein in an extended precoding matrix corresponding to an initial precoding matrix, in a column vector of any two extended precoding matrices, an extended precoding matrix is mapped to a codeword. The column vector is different from the column vector mapped to any codeword in another extended precoding matrix.
The method according to claim 9, wherein if the number of column vectors of the initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.
The method of any one of claims 9 to 13 further comprising:

The base station sends valid precoding matrix indication information to the terminal, where the effective precoding matrix indication information is used to indicate an effective precoding matrix in the initial precoding matrix set.
A terminal, comprising:

An extension module, configured to expand an initial precoding matrix set according to an agreed column vector arrangement manner, to obtain an extended precoding matrix set;

a measuring module, configured to perform CSI measurement according to the extended precoding matrix set;

And a feedback module, configured to feed back the measured CSI to the base station.
The terminal according to claim 16, wherein the extension module is specifically configured to:

For a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set is extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix;

For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.
The terminal according to claim 16, wherein the initial precoding matrix set comprises N subsets, each subset corresponds to a value of a transmission rank, and the number of column vectors of an initial precoding matrix in a subset is equal to The value of the transmission rank corresponding to the subset, and N is an integer greater than or equal to 1.
The terminal according to claim 18, wherein the column vectors used in the expansion of the initial precoding matrix corresponding to the same transmission rank value are arranged in the same manner.
The terminal according to claim 16, wherein in all the extended precoding matrices corresponding to an initial precoding matrix, among the column vectors of any two extended precoding matrices, one extended precoding matrix is mapped to one codeword. The column vector is different from the column vector mapped to any codeword in another extended precoding matrix.
The terminal according to claim 16, wherein if the number of column vectors of the initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.
The terminal according to any one of claims 16 to 21, wherein the measurement module is specifically configured to:

Using the extended precoding matrix in the extended precoding matrix set as a precoding matrix for downlink transmission, and performing one of precoding matrix indication PMI, rank indication RI, and channel quality indicator CQI according to the extended precoding matrix set. Or a measurement of a plurality of CSIs, wherein the PMI is an index of the extended precoding matrix in the set of extended precoding matrices.
A base station, comprising:

An extension module, configured to expand an initial precoding matrix set according to an agreed column vector arrangement manner, to obtain an extended precoding matrix set;

a receiving module, configured to receive CSI that is measured and fed back by the terminal according to the extended precoding matrix set, where the extended precoding matrix set according to which the terminal performs CSI measurement and feedback is that the terminal arranges according to the agreed column vector arrangement manner The initial precoding matrix set is expanded.
The base station according to claim 23, wherein the expansion module is specifically configured to:

For a part of the initial precoding matrix in the initial precoding matrix set, the initial precoding matrix set is extended according to an agreed column vector arrangement manner to obtain an extended precoding matrix;

For the remaining partial precoding matrix in the initial precoding matrix set, the partial initial precoding matrix is used as a corresponding extended precoding matrix.
The base station according to claim 23, wherein the initial precoding matrix set comprises N subsets, each subset corresponding to a value of a transmission rank, and the number of column vectors of an initial precoding matrix in a subset is equal to The value of the transmission rank corresponding to the subset, and N is an integer greater than or equal to 1.
The base station according to claim 25, wherein the column vectors used in the expansion of the initial precoding matrix corresponding to the same transmission rank value are arranged in the same manner.
The base station according to claim 23, wherein, in all the extended precoding matrices corresponding to an initial precoding matrix, among the column vectors of any two extended precoding matrices, one extended precoding matrix is mapped to one codeword. The column vector is different from the column vector mapped to any codeword in another extended precoding matrix.
The base station according to claim 23, wherein if the number of column vectors of the initial precoding matrix is greater than a set threshold, the extended precoding matrix corresponding to the initial precoding matrix is the same as the initial precoding matrix.
A terminal, comprising: a transceiver, a processor and a memory;

The transceiver is configured to receive and/or send a message;

The memory is configured to store computer program instructions;

The processor, coupled to the memory, for reading computer program instructions stored by the memory, and performing the method of any one of claims 1-8.
A base station, comprising: a transceiver, a processor, and a memory;

The transceiver is configured to receive and/or send a message;

The memory is configured to store computer program instructions;

The processor, coupled to the memory, for reading the computer program instructions stored in the memory and performing the method of any one of claims 9-15.