WO2016141778A1 - Channel state information acquisition method, and channel state information feedback method and apparatus - Google Patents

Abstract

Disclosed are a channel state information acquisition method, and a channel state information feedback method and apparatus. The method comprises: a terminal performs, according to a received pilot signal, channel estimation to obtain a channel estimation value of A antenna ports, wherein the A antenna ports are A antenna ports sending the pilot signal by a network device; the terminal determines, according to the channel estimation value of the A antenna ports, Q antenna ports, wherein L≤Q≤A, L is a value of rank indication (RI) adopted when the network device sends downlink data to the terminal, or L is a value of channel rank indication (RI) determined by the terminal; and the terminal determines, according to the Q antenna ports, first order pre-coding matrix indication information and feeds back channel state information (CSI) containing the first order pre-coding matrix indication information to the network device, wherein the first order pre-coding matrix indication information is used for indicating an index of the Q antenna ports in the A antenna ports sending the pilot signal.

Description

Channel state information acquisition method, channel state information feedback method and device

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. 201510101468.4 filed on Jan. 6, 2015 in China, and the entire disclosure of herein.

Technical field

The present disclosure relates to the field of communications technologies, and in particular, to a channel state information acquiring method, a channel state information feedback method, and a device.

Background technique

In the existing multi-input multi-output (MIMO) antenna system based on Frequency Division Duplexing (FDD), the number of antennas of network equipment is relatively small, and it is not a problem for the terminal to measure the complete MIMO channel matrix. . The pilot used to measure the channel state information (CSI) usually configures an antenna port for each antenna to transmit a pilot signal.

In LTE-Advanced (LTE-Advanced is the evolution of LTE, LTE is the abbreviation of Long Term Evolution, Chinese is Long Term Evolution), the pilot used to measure CSI is called a reference signal, including a cell reference signal (CRS, Cell Reference Signal) and channel state information reference signal (CSI-RS). The terminal determines an optimal channel rank indication (RI, Rank Indication), a precoding matrix indicator (PMI), and a channel quality indicator (CQI) based on the measured CSI, and reports to the network through the feedback channel. device.

Massive MIMO technology can effectively increase spatial resolution and increase system capacity by arranging large-scale antenna arrays on network devices, usually hundreds of antennas. When the antenna is arranged in a two-dimensional uniform rectangular array (URA, Uniform Rectangular Array), high three-dimensional (horizontal and vertical) resolution can be achieved.

At present, there is no technical solution for CSI feedback and acquisition for large-scale MIMO systems.

Summary of the invention

The embodiments of the present disclosure provide a channel state information acquisition method, a channel state information feedback method, and a device for implementing feedback and acquisition of channel state information.

A channel state information feedback method provided by an embodiment of the present disclosure includes:

The terminal performs channel estimation according to the received pilot signal, and obtains channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device;

Determining, by the terminal, the Q antenna ports according to the channel estimation values of the A antenna ports, where L ≤ Q ≤ A, where L is the value of the rank indication RI used by the network device to send downlink data to the terminal Or, L is a value of the channel rank indication RI determined by the terminal;

Determining, by the terminal, the first level precoding matrix indication information according to the Q antenna ports, and feeding back the channel state information CSI including the first level precoding matrix indication information to the network device, where the first level precoding The matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.

An embodiment of the present disclosure provides a terminal, including:

a channel estimation unit, configured to perform channel estimation according to the received pilot signal, to obtain channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device;

a determining unit, configured to determine Q antenna ports according to channel estimation values of the A antenna ports, where L≤Q≤A, L is a rank indication RI used by the network device to send downlink data to the terminal Value, or L is the value of the channel rank indication RI determined by the terminal;

a sending unit, configured to determine first stage precoding matrix indication information according to the Q antenna ports, and feed back channel state information CSI including the first level precoding matrix indication information to a network device, where the first level The precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.

According to the channel state information feedback method and terminal provided by the embodiment of the present disclosure, the terminal performs channel estimation on the received pilot signal, and determines Q from among the A antenna ports of the network device according to the estimated equivalent channel. The antenna port is measured by the channel state information, thereby obtaining channel state information. When the above embodiment is applied to the MIMO channel matrix measurement process, the terminal converts the measurement of the MIMO channel matrix into determining the Q for the channel state from among the A antenna ports of the network device. The antenna port of the information measurement is equivalent to the measurement of all pilot antenna port signals of the network device and the selection of the antenna port, thereby determining the channel state information of the terminal.

An embodiment of the present disclosure provides a channel state information acquiring method, where the method includes:

The network device receives the channel state information CSI fed back by the terminal, where the CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting the pilot signal. An index of the A antenna ports, where the first level precoding matrix indication information is determined by the Q antenna ports determined by the terminal according to the channel estimation values of the A antenna ports, and L≤ Q ≤ A, L is the value of the rank indication RI used by the network device to send downlink data to the terminal, or L is the value of the channel rank indication RI determined by the terminal;

Determining, by the network device, a first level precoding matrix according to the received CSI and a beamforming vector corresponding to the A antenna ports;

The network device determines to transmit a precoding matrix according to the first level precoding matrix.

An embodiment of the present disclosure provides a network device, including:

a receiving unit, configured to receive channel state information CSI fed back by the terminal, where the CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting An index in the A antenna ports of the frequency signal, where the first level precoding matrix indication information is determined by the Q antenna ports determined by the terminal according to the channel estimation values of the A antenna ports, according to the Q antenna ports. And L ≤ Q ≤ A, L is a value of a rank indication RI used by the network device to send downlink data to the terminal, or L is a value of a channel rank indication RI determined by the terminal;

a first determining unit, configured to determine, according to the received CSI and a beamforming vector corresponding to the A antenna ports, a first level precoding matrix;

And a second determining unit, configured to determine, according to the first level precoding matrix, a transmit precoding matrix.

The embodiment of the present disclosure further provides a network device, including a processor, a memory, and a transceiver; wherein the processor is configured to read a program in the memory, and perform the following process: receiving channel state information CSI fed back by the terminal The CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signal, where The first level precoding matrix indication information is based on the terminal After the Q antenna ports determined by the channel estimation values of the A antenna ports are determined according to the Q antenna ports, L ≤ Q ≤ A, where L is the rank used by the network device to send downlink data to the terminal. Instructing the value of the RI, or L is the value of the channel rank indication RI determined by the terminal; and determining the first level pre-determination according to the received CSI and the beamforming vector corresponding to the A antenna ports. An encoding matrix; determining a transmitting precoding matrix according to the first level precoding matrix; the transceiver is configured to receive and transmit data.

Embodiments of the present disclosure also provide a terminal including a processor, a memory, and a transceiver. The processor is configured to read a program in the memory, and perform the following process: performing channel estimation according to the received pilot signal to obtain channel estimation values of A antenna ports, where the A antenna ports are The network device sends the A antenna ports of the pilot signal; and is configured to determine Q antenna ports according to the channel estimation values of the A antenna ports, where L≤Q≤A, L is that the network device sends the terminal to the terminal The rank used in the downlink data indicates the value of the RI, or L is the value of the channel rank indicator RI determined by the terminal; and is used to determine the first-level precoding matrix indication information according to the Q antenna ports, and The channel state information CSI including the first level precoding matrix indication information is fed back to the network device, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting A pilot port of the pilot signal. The index in the transceiver; the transceiver is used to receive and transmit data.

According to the channel state information acquiring method and the network device provided by the embodiment of the present disclosure, the channel state information fed back by the network device includes at least first level precoding matrix indication information, where the first level precoding matrix indication information is The terminal is determined according to the Q antenna ports determined by the channel estimation values of the A antenna ports, and can reflect the channel state information of each terminal to a certain extent, so that when the foregoing embodiment is applied to the massive MIMO system, the utilization is large. The characteristics of the scale MIMO system simplify the design and implementation of large-scale MIMO systems.

DRAWINGS

FIG. 1 is a schematic flowchart of a method for acquiring channel state information according to an embodiment of the present disclosure;

2 is a schematic diagram of a spatial range that a spatial beam direction should cover;

3 is a schematic diagram of a process of transmitting a pilot signal on an antenna port of an antenna device in a network device according to an embodiment of the present disclosure;

FIG. 4 is a schematic flowchart of a channel state information feedback method according to an embodiment of the present disclosure;

FIG. 5 is a schematic flowchart of a method for acquiring channel state information according to an embodiment of the present disclosure;

FIG. 6 is a structural diagram of a network device according to an embodiment of the present disclosure;

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

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

FIG. 9 is a structural diagram of a user equipment according to an embodiment of the present disclosure.

detailed description

In the embodiment of the present disclosure, an Orthogonal Frequency Division Multiplexing (OFDM) system is taken as an example. For example, an LTE-Advanced system, all descriptions are directed to one subcarrier unless otherwise specified. In the embodiment of the present disclosure, the lowercase bold letters represent column vectors, and the uppercase bold letters represent matrixes.

Represents the Kronecker product, the superscript "T" indicates the transpose of the matrix or vector, and the superscript "H" indicates the conjugate transpose of the matrix or vector.

As shown in FIG. 1 , a method for acquiring channel state information provided by an embodiment of the present disclosure includes:

Step 101: The network device receives the CSI fed back by the terminal, where the CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting the pilot signal. An index in the A antenna ports, where the first-stage precoding matrix indication information is determined according to the Q antenna ports determined by the channel estimation values of the A antenna ports, and is determined according to the Q antenna ports, L≤Q ≤ A, L is the value of the rank indication RI used by the network device to send downlink data to the terminal, or L is the value of the channel rank indication RI determined by the terminal.

It should be noted that there are many methods for determining the value of the RI determined by the terminal, and the embodiment of the present disclosure does not limit this. After determining the value of the RI, the terminal may also send the value of the RI to the network device as part of the CSI. The network device may determine the data layer used when transmitting the downlink data to the terminal according to the value of the received RI (Layer). ) and the number of data layers.

The value of L can be determined according to the actual situation.

For example, in a SU-MIMO (Single-User MIMO) system, the number of data layers and data layers used by the network device to transmit downlink data to the terminal is generally equal to the value of the RI sent by the terminal. Time L is used when the network device sends downlink data to the terminal. The rank indicates the value of RI, or L is the value of the channel rank indication RI determined by the terminal.

For example, in a MU-MIMO (Multi-User MIMO) system, the number of data layers and data layers used by the network device to transmit downlink data to the terminal may not be equal to the value of the RI sent by the terminal. At this time, L is the value of the channel rank indication RI determined by the terminal.

Step 102: The network device determines a first-stage precoding matrix according to the received CSI and a beamforming vector corresponding to the A antenna ports.

Step 103: The network device determines, according to the first level precoding matrix, a transmit precoding matrix.

Before step 101, the network device sends a pilot signal to the terminal through the A antenna ports.

Optionally, the process of the network device sending the pilot signal to the terminal through the A antenna ports is as follows:

Step 1: The network device determines A antenna ports that transmit pilot signals, spatial beam directions corresponding to each antenna port, and resources used for transmitting pilot signals, where each antenna port corresponds to a spatial beam direction.

Specifically, in step 1, the network device needs to determine the antenna corresponding to each pilot port to transmit the pilot signal and the required time-frequency resource, while determining the A antenna ports used for transmitting the pilot signal. Each antenna port corresponds to all or part of the antennas of the network device. If more spatial beam directions need to be formed than the number of configurable antenna ports, multiple sets of pilot processes, such as CSI-RS process (LTE), can be set. All pilot processes are transmitted through orthogonal time-frequency resources. At the same time, all spatial beam directions corresponding to the antenna ports included in all pilot processes should cover the entire space to be covered as much as possible, as shown in Figure 2. The dotted line 201 in Fig. 2 is the spatial extent that all spatial beam directions should cover, and the solid line 202 is the spatial extent covered by a spatial beam direction.

The network device can determine the spatial beam direction, the number of beams in each direction, and the beam width corresponding to each antenna port according to the distribution of the terminal. Each antenna port occupies at least one time-frequency resource. When multiple antenna ports adopt Code Division Multiple (CDM) mode, each antenna port can occupy more than one time-frequency resource.

Step 2: The network device determines, for each antenna port of the A antenna ports, a beamforming vector of the spatial beam direction corresponding to each antenna port in the first dimension, and a beamforming vector in the second dimension, And determining a three-dimensional spatial beamforming vector of the beam corresponding to the antenna port according to the beamforming vector in the first dimension and the beamforming vector in the second dimension.

MIMO systems in large-scale, network devices typically arranged in a two-dimensional antenna array uniform rectangular array, comprising a total of N _T transmit antennas, there are N _x and N _y antennas on a first dimension and a second dimension, respectively, there is N _T =N _x N _y , wherein the first dimension is a vertical dimension and the second dimension is a horizontal dimension, or the first dimension is a horizontal dimension and the second dimension is a vertical dimension.

In step 2, when the network device sends the pilot signal, the set of A antenna ports included in all pilot processes is ω _A = {1, 2, ..., A}, and for any antenna port a ∈ ω _A occupies M ≥ 1 time-frequency resource. The following is an example in which the antenna port a ∈ ω _A and the antenna corresponding to the antenna port a are all antennas of the network device.

When the antenna corresponding to the antenna port a is all the antennas of the network device, the spatial beamforming vector of the spatial beam direction corresponding to the antenna port a in the first dimension is:

among them,

The corresponding weight of the uth antenna in the first dimension in the antenna port a, 1 ≤ u ≤ Nx.

The spatial beamforming vector of the spatial beam direction corresponding to the antenna port a in the second dimension is:

among them,

The corresponding weight of the uth antenna in the second dimension in the antenna port a, 1 ≤ u ≤ Ny.

Then the three-dimensional spatial beamforming vector of the beam corresponding to the antenna port a is:

Then, the pilot signal vector of the antenna port a that is transmitted on the mth time-frequency resource and subjected to all antenna beamforming is s ^{(a, m)} = w ^(a) p ^{(a, m)} , where p ^{(a) , m)} is the pilot symbol on the mth time-frequency resource.

Specifically, shown in Figure 3, Figure 3 illustrates a network device port during a transmit antenna a pilot signal in all N _T antennas. In FIG. 3, the pilot symbol p ^{(a, m) of the} antenna port a on the mth time-frequency resource is mapped to each antenna, and each antenna will be based on the shaped weight coefficient on the pilot symbol p ^{(a, m)} Perform a multiplication operation to form a pilot signal vector that is shaped by all antenna beams. In Figure 3,

The corresponding weighting factor for the jth antenna in antenna port a,

The pilot signal transmitted on the corresponding time-frequency resource of the j-th antenna in the antenna port a, 1 ≤ j ≤ N _T .

In step 2, the pilot signal sent by the antenna port a on the mth time-frequency resource may also be sent by forming part of the antenna in the spatial beam direction corresponding to the antenna port a, for example, two-dimensionally uniform for cross-polarization. A design implementation of an antenna port of a rectangular antenna array in which all or part of the antennas of the same polarization direction.

When the antenna corresponding to the antenna port a is a partial antenna of the network device, the beamforming vector w ^(a) only has a shaping weight coefficient on the corresponding partial antenna.

among them,

For the jth weighting coefficient of the antenna participating in forming the antenna port a, it can be considered that the shaping weight coefficient of the other antennas not participating in the formation of the antenna port a is zero. For example, in the design implementation of the antenna port of the cross-polarized two-dimensional uniform rectangular antenna array, any antenna port a _i , a _j ∈ ω _A is transmitted by the antenna of the same polarization direction to form a corresponding spatial beam direction, and the beamforming vector can be written. The following form:

among them

Representing the beamforming vectors of the two polarization directions corresponding to the antenna ports a _i , a _j , respectively

Representing the beamforming vectors of the first dimension and the second dimension in the polarization direction corresponding to the antenna port a _i , respectively,

The beamforming vectors of the first dimension and the second dimension in the polarization direction corresponding to the antenna port a _j are respectively indicated.

Step 3: The network device performs beamforming and transmitting on the pilot signal according to the three-dimensional spatial beamforming vector of each antenna port of the A antenna ports and the time-frequency resource used by the pilot signal.

In step 3, the network device transmits a pilot signal of each antenna port through an antenna corresponding to the antenna port.

According to the above described procedure, the network device can convert the measurement of the MIMO channel matrix into the measurement and selection of the spatial beam direction by corresponding each antenna port to a spatial beam direction, thereby reducing the overhead of the terminal CSI measurement pilot.

In step 101, the CSI received by the network device includes at least first stage precoding matrix indication information, and the network device may determine, according to the first level precoding matrix indication information, the A antenna ports that send the pilot signal, and the terminal selects Which Q antenna ports are formed, so that the first stage precoding matrix is formed according to the Q beamforming vectors corresponding to the Q antenna ports selected by the terminal.

Further, the CSI received by the network device may further include one or a combination of the following information:

The second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set. The second precoding matrix is a power level normalized Q × L dimensional matrix, the present disclosure employed in the embodiment represented by V _L. The second-stage precoding matrix V _L can be obtained by calculating a Singular Value Decomposition (SVD), a matrix composed of L singular vectors corresponding to the largest L singular values, and performing power normalization and quantization processing, or The indication information and the RI are indicated from the second level codebook set according to the second level precoding matrix.

RI, the RI is a channel rank indication reported by the terminal to the network device, and the terminal can determine the effective data layer of the Physical Downlink Shared Channel (PDSCH) supported by the terminal by reporting the RI. The method for determining the rank indication reported by the terminal to the network device is various, and the embodiment of the present disclosure does not limit this, and details are not described herein again.

The channel quality indicates CQI, and the CQI is a quantized value of Signal to Interference plus Noise Ratio (SINR). Determining, by the following manner, the CQI: determining, according to the first-level precoding matrix indication information, a first equivalent channel formed by the Q channel estimation values corresponding to the Q antenna ports, according to the second level precoding matrix indication The information and RI determine a second level precoding matrix, and determine a second equivalent channel according to the first equivalent channel and the second level precoding matrix, according to the second equivalent channel, power of the interference signal, and noise The power of the signal determines the SINR, and the CQI is determined based on the SINR.

When the rank is 1, the Q antenna ports selected by the terminal are a ₁ , a ₂ , . . . , a _Q , and the second-stage precoding matrix is a Q×1 dimensional column vector v ₁ , where N _R is the receiving antenna of the terminal. The number, SINR can be calculated according to the following formula:

Where γ ₁ is the calculated SINR,

To interfere with the power of the signal,

For the power of the noise signal, ||·|| represents the norm of the matrix,

For the first equivalent channel, the dimension is N _R ×Q, which is obtained by the terminal directly measuring and selecting the A antenna ports, wherein

It is the channel estimation value of the a (a ∈ ω _A ) antenna port, and the dimension is N _R ×1. H is a channel matrix on one subcarrier, and the dimension is N _R × N _T .

Generally, the CSI fed back by the network device includes the first-level precoding matrix indication information, the number Q of antenna ports selected by the terminal, the second-level precoding matrix indication information, the RI, the CQI, and the like. When the network device specifies the rank index used by the network device to send downlink data to the terminal The value of the RI is 1, and it is specified that the terminal can only select one antenna port after measuring the antenna ports, that is, Q=1. In this case, the CSI fed back by the terminal may not include the number of antenna ports selected by the terminal. And the second level precoding matrix indication information.

In step 102, after receiving the CSI including the first-level precoding matrix indication information sent by the terminal, the network device determines, according to the first-level precoding matrix indication information, that the A antenna ports that send the pilot signal are The Q antenna ports selected by the terminal form a first-stage precoding matrix according to the Q beamforming vectors corresponding to the Q antenna ports selected by the terminal.

Specifically, the Q antenna ports selected by the terminal indicated by the first-stage precoding matrix indication information are a ₁ , a ₂ , . . . , a _Q , and then the first-level precoding matrix obtained by the network device is:

Wherein W ₁ is a first-stage precoding matrix, and w ^(a) is a beamforming vector corresponding to an antenna port a (a ∈ ω _A ).

In the design implementation of the antenna port of the cross-polarized two-dimensional uniform rectangular antenna array, any one of the antenna ports is transmitted by the antenna of the same polarization direction to form a corresponding spatial beam direction, and the antenna serial number is in a certain dimension in one polarization direction. Sorting, then sorting by the same dimension in another polarization direction, the first level precoding matrix can be further written as:

Here, the antenna ports a ₁ , . . . , a _i correspond to one polarization direction, and the antenna ports a _i+1 , . . . , a _Q correspond to another polarization direction.

In step 103, the network device determines to transmit a precoding matrix according to the first level precoding matrix.

Specifically, the network device may determine to send the precoding matrix according to the following formula:

Where W is the transmission precoding matrix, W ₁ is the first level precoding matrix, the dimension is N _T ×Q, and V _L is the second level precoding matrix, and the dimension is Q×L, where L is the value of RI ,

Is the power normalization factor.

After the network device determines that the precoding matrix is transmitted, the network may be reconstructed according to the sending precoding matrix. The channel matrix of the device to the terminal. When the network device needs to reconstruct the channel matrix of the network device to the terminal, the network device can determine the channel matrix of the network device to the terminal according to the following formula:

among them,

For the channel matrix, W is the transmit precoding matrix.

Based on the pilot signals transmitted by the network device in the A antenna ports described above, each antenna port corresponds to a spatial beam direction, so the terminal can convert the MIMO channel matrix measurement into a problem of measuring the spatial beam direction of each terminal. . The terminal can select multiple spatial beam directions according to actual conditions, and can calculate channel quality (CQI) according to selected multiple spatial beams. Generally, the number of spatial beams selected by the terminal is much smaller than the number of large-scale antennas of the network device, so that the terminal CSI measurement pilot overhead can be reduced.

As shown in FIG. 4, an embodiment of the present disclosure provides a channel state information feedback method, where the method includes:

Step 401: The terminal performs channel estimation according to the received pilot signal, and obtains channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device.

Step 402: The terminal determines, according to channel estimation values of the A antenna ports, Q antenna ports, where L≤Q≤A, where L is a rank indication RI used by the network device to send downlink data to the terminal. Or, L is the value of the channel rank indication RI determined by the terminal.

It should be noted that there are many methods for determining the value of the RI determined by the terminal, and the embodiment of the present disclosure does not limit this.

For the value of L, refer to the description in step 101, and details are not described herein again.

Step 403: The terminal determines the first-level precoding matrix indication information according to the Q antenna ports, and feeds the CSI including the first-level precoding matrix indication information to the network device, where the first level precoding The matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.

In the foregoing process, the process of transmitting the pilot signal by the network device may be as described in FIG. 1 above, and the pilot signal may be sent in other manners, which is not limited in this embodiment of the present disclosure.

In the embodiment of the present disclosure, the number of receiving antennas of the terminal is N _R , and N _{R is} greater than or equal to 1, and the antenna port a occupying the mth time-frequency resource belongs to a set of A antenna ports of the network device ω _A ={1, 2, ..., a}, and the antenna ports corresponding to a network device transmitting antennas all N _T antennas, the transmit antenna N _T is a two-dimensional rectangular array with uniform polarization; or cross-polarized transmit antenna The two-dimensional uniform rectangular array, the antenna corresponding to the antenna port a is the same polarization direction antenna in the network device. At the same time, the pilot symbol corresponding to antenna port a is normalized power.

In step 401, the pilot signal received by the terminal is sent by the network device through the A antenna ports, where each antenna port of the A antenna ports corresponds to a spatial beam direction, and each antenna port occupies at least one time-frequency resource. When multiple antenna ports adopt the code division multiplexing mode, each antenna port may occupy more than one time-frequency resource. At the same time, the three-dimensional spatial beamforming vector corresponding to the spatial beam direction corresponding to each antenna port is determined according to the beamforming vector of the antenna port in the first dimension and the beamforming vector in the second dimension, wherein The first dimension is a vertical dimension, the second dimension is a horizontal dimension, or the first dimension is a horizontal dimension and the second dimension is a vertical dimension.

The pilot signal vector of all antenna beamforming transmitted by the antenna port a(a ∈ ω _A ) on the mth time-frequency resource is s ^{(a, m)} = w ^(a) p ^{(a, m)} , wherein , w ^(a) is a three-dimensional spatial beamforming vector of the beam corresponding to the antenna port a, and p ^{(a, m)} is a pilot symbol on the mth time-frequency resource. At this time, the channel matrix of the network device to the terminal on one subcarrier is a matrix H of N _R ×N _T dimensions. The terminal receives the pilot signal as a vector of N _R ×1 dimension on the mth time-frequency resource occupied by the antenna port a:

r ^(a,m) =Hs ^(a,m) +i ^(a,m) +n ^(a,m) =Hw ^(a) p ^(a,m) +i ^(a,m) +n ^{(a, m)} ............(11)

Where s ^{(a, m)} is the N _T × 1 dimensional pilot signal vector that is transmitted by the antenna port a on the mth time-frequency resource and all antenna beams are shaped, i ^{(a, m)} , n ^{(a , m)} are N _R × 1 dimensional interference signal vectors and noise signal vectors, respectively.

The pilot signal on the time-frequency resource occupied by each antenna port is integrated, and the terminal obtains the A channel estimation values corresponding to the A antenna ports that the network device transmits the pilot signal. The channel estimation value of antenna port a is:

Where w ^(a) is the three-dimensional spatial beamforming vector of antenna port a, and E ^(a) is the channel estimation error matrix of antenna port a, a ∈ ω _A . The terminal obtains the channel estimation value of the A antenna ports.

In step 402, the terminal needs to estimate the channel estimation value of the A antenna ports from the A antennas. Select Q antenna ports in the port to determine the CSI feedback to the network device.

Considering that the terminal determines the computational complexity of CSI according to the selected Q antenna ports, the terminal can select only one antenna port to determine the CSI. However, considering many scatterers present on the propagation path, the pilot signal received by the terminal is likely to be a superposition of signals passing through multiple propagation paths. Therefore, in order to obtain a highly accurate CSI, the number of terminals at the antenna port is required. Within the range of values, determine all possible antenna port combinations and determine the Q antennas that maximize the channel throughput or capacity between the terminal and the network device or the pilot signal received by the terminal among all possible antenna port combinations. A port, wherein a channel throughput or capacity corresponding to each possible antenna port combination or a pilot signal received power of the terminal is determined according to a channel estimation value corresponding to the possible antenna port combination.

The value of the number of antenna ports is generally greater than or equal to the rank L of the channel and less than or equal to A. The network device may also specify an upper limit of the value range of the number of antenna ports. For example, the number of antenna ports specified by the network device ranges from Q _max .

At the same time, the network device can also specify the number of antenna ports to be selected for the terminal. For example, the number of designated antenna ports is Q, and L≤Q≤A, in which case the terminal only needs to select among the A antenna ports. The channel throughput or capacity between the terminal and the network device or the combination of Q antenna ports when the signal receiving power of the terminal is the largest. When the network device does not specify the number of the number of antenna ports to be selected or the upper limit of the number of antenna ports, the lower limit of the range of the number of antenna ports selected by the terminal is greater than or equal to L, and the upper limit of the value range is the network. The number of antenna ports on which the device sends pilot signals, that is, less than or equal to A.

Regardless of whether the network device specifies the number of antenna ports to be selected for the terminal, there are many combinations of antenna ports in the A antenna ports for terminal selection. Taking the calculation of the throughput or capacity between the terminal and the network device as an example, the terminal selects the set ω _Q of the Q antenna ports with the highest throughput or capacity among the A antenna ports according to the following method:

among them,

For the function of calculating the throughput or capacity between the terminal and the network device, the function is a function well known to those skilled in the art, and the function will not be described in detail here, only the function of the function is described, and Q _max is the antenna selected by the terminal. The upper limit of the value range of the number of ports, L ≤ Q _max ≤ A, ω _k indicates that a set of _k antenna ports is selected among A antenna ports, and Ω _k indicates that when _k antenna ports are selected among A antenna ports The set of possible ω _k , L ≤ _k ≤ Q _max ,

Indicates a first equivalent channel formed by channel estimation values corresponding to k antenna ports selected among A antenna ports, and V _L can be calculated

The singular value decomposition obtains a matrix composed of L singular vectors corresponding to the largest L singular values and performs power normalization and quantization processing, and can also be selected from the second-level codebook set, i is an interference signal vector, n For the noise signal vector, P' is the power normalization factor of the precoding matrix.

When L=1, the second-stage precoding matrix degenerates into a Q×1 column vector. When L=1 and the network device specifies Q _max =1, the second-stage precoding matrix is further degraded to a scalar v ₁ =1. At this time, the above problem can be simplified as selecting channel estimation values from the A antenna ports. The square of the norm is the largest, that is, the antenna port with the highest received power.

The terminal calculates each possible antenna port combination in each of the A antenna ports, and then selects a combination of Q antenna ports when the channel throughput or capacity between the terminal and the network device or the signal receiving power of the terminal is maximized. The amount of calculation of the process is very large. In order to reduce the computational complexity, the greedy method is used for searching in the embodiment of the present disclosure, and the basic idea is to increase the number of antenna ports used one by one until the throughput or capacity or the pilot signal receiving power of the terminal no longer increases or reaches. The largest can choose the rank. Specifically, the detailed description of the greedy law is as follows.

As shown in FIG. 5, the schematic diagram of the greedy method provided by the embodiment of the present disclosure includes the following steps:

Step 501: Determine a value range of the number of antenna ports used for CSI measurement.

Step 502, setting k=1, T0=0;

Step 503: Calculate, when selecting k antenna ports from the A antenna ports, determine a throughput or capacity corresponding to each possible antenna port combination or a pilot signal received power of the terminal, and select a throughput or a combination of antenna ports having the largest capacity of the pilot signal of the terminal or the terminal;

Step 504, if k < Q _max , then proceeds to step 505, otherwise proceeds to step 507, Q _max is the upper limit of the range of values, L ≤ Q _max ≤ A;

Step 505: If T _k >T _k-1 , go to step 506, otherwise, go to step 507; wherein Tk is the throughput or capacity or the terminal when k antenna ports are selected from the A antenna ports The pilot signal receives the throughput or capacity corresponding to the antenna port combination with the highest power or the pilot signal received power of the terminal, and T _k-1 is when _k-1 antenna ports are selected from the A antenna ports. The throughput or capacity corresponding to the throughput or capacity or the combination of the antenna signal receiving power of the terminal, or the pilot signal receiving power of the terminal;

Step 506, let k = k + 1 and go to step 503;

Step 507: Determine an antenna port in the antenna port combination in which the currently determined throughput or capacity or the pilot signal receiving power of the terminal is the largest, as an antenna port for CSI measurement.

After the terminal determines the Q antenna ports for CSI measurement, it can determine the CSI fed back to the network device. Specifically, in step 403, the CSI determined by the terminal includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports used for CSI measurement are in the transmission guide. The index in the A antenna ports of the frequency signal. Further, the CSI determined by the terminal may further include one or a combination of the following information:

The second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set; the second level precoding matrix V _L is power return a matrix of Q×L dimensions; the second-stage precoding matrix V _L can be obtained by calculating a singular value decomposition, a matrix composed of L singular vectors corresponding to the largest L singular values, and performing power normalization and quantization processing. , can also be selected from the second level codebook set;

RI, the RI is a channel rank indication reported by the terminal to the network device, and the terminal reports the effective data layer of the PDSCH supported by the network device terminal by reporting the RI;

The CQI may be determined according to the following manner: determining, according to the first-level precoding matrix indication information, a first equivalent channel formed by the Q channel estimation values corresponding to the Q antenna ports, according to the second level pre- Encoding matrix indication information and the RI determining a second level precoding matrix, determining a second equivalent channel according to the first equivalent channel and the second level precoding matrix, according to the second equivalent channel, interference The power of the signal and the power of the noise signal determine the SINR, and the CQI is determined based on the SINR.

In general, the CSI fed back by the terminal includes the first-level precoding matrix indication information and the terminal selection. The number of selected antenna ports Q, second-level precoding matrix indication information, RI, channel quality indication CQI, and the like. When the network device specifies that the RI value of the downlink data sent by the network device to the terminal is 1, and the terminal specifies that only one antenna port can be selected for CSI measurement in the A antenna ports, the terminal feeds back to the network. The CSI of the device may not include the number Q of antenna ports selected by the terminal, and the second-level precoding matrix indication information.

For the foregoing method flow, the embodiment of the present disclosure further provides a network device and a terminal. The specific content of the network device and the terminal may be implemented by referring to the foregoing method, and details are not described herein again.

As shown in FIG. 6, an embodiment of the present disclosure provides a network device, including:

The receiving unit 601 is configured to receive channel state information CSI fed back by the terminal, where the CSI includes at least first level precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting. An index in the A antenna ports of the pilot signal, the first level precoding matrix indication information is determined according to the Q antenna ports determined by the channel estimation values of the A antenna ports, and determined according to the Q antenna ports And L ≤ Q ≤ A, L is a value of a rank indication RI used by the network device to send downlink data to the terminal, or L is a value of a channel rank indication RI determined by the terminal;

a first determining unit 602, configured to determine, according to the received CSI and a beamforming vector corresponding to the A antenna ports, a first level precoding matrix;

The second determining unit 603 is configured to determine, according to the first level precoding matrix, a transmit precoding matrix.

Optionally, the CSI received by the receiving unit 601 further includes one or a combination of the following information:

a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

RI;

The channel quality indicates the CQI.

Optionally, the second determining unit 603 is specifically configured to:

The transmitting precoding matrix is determined according to the following formula:

Wherein, W is the precoding matrix, _{W. 1} is a first stage of the pre-coding matrix, V _L is the second level pre-coding matrix, the second stage pre-coding matrix by said second pre-coding stage The matrix indicates the matrix indicated by the information,

Is the power normalization factor.

Optionally, the receiving unit 601 is further configured to:

The network device determines A antenna ports that transmit pilot signals, a transmit antenna corresponding to each antenna port, a spatial beam, and a resource used for transmitting a pilot signal, where each antenna port corresponds to one spatial beam;

Determining, by the network device, a beamforming vector of a spatial beam corresponding to each antenna port in a first dimension, and a beamforming vector in a second dimension, for each of the A antenna ports, And determining, according to the beamforming vector in the first dimension and the beamforming vector in the second dimension, a three-dimensional spatial beamforming vector of a beam corresponding to the antenna port;

The network device beamforms the pilot signal according to a three-dimensional spatial beamforming vector of each antenna port of the A antenna port and a resource used by the pilot signal, and transmits the pilot signal in all or part of the transmitting antenna.

Optionally, the first determining unit 602 is specifically configured to:

According to the distribution of the terminal, the direction of the spatial beam corresponding to each antenna port, the number of beams in each direction, and the beam width are determined.

As shown in FIG. 7, an embodiment of the present disclosure provides a terminal, including:

The channel estimation unit 701 is configured to perform channel estimation according to the received pilot signal, to obtain channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device;

a determining unit 702, configured to determine Q antenna ports according to channel estimation values of the A antenna ports, where L≤Q≤A, L is a rank indication RI used by the network device to send downlink data to the terminal Or, L is the value of the channel rank indication RI determined by the terminal;

The sending unit 703 is configured to determine first stage precoding matrix indication information according to the Q antenna ports, and feed back channel state information CSI including the first level precoding matrix indication information to the network device, where the first The precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.

Optionally, the CSI that is sent by the sending unit 703 to the network device further includes one or a combination of the following information:

Second stage precoding matrix indication information, the second level precoding matrix indication information is used to indicate An index of the second level precoding matrix in the second level codebook set;

RI;

The channel quality indicates the CQI.

Optionally, the CQI is determined according to the following manner:

Determining, according to the first level precoding matrix indication information, a first equivalent channel formed by Q channel estimation values corresponding to the Q antenna ports;

Determining a second level precoding matrix according to the second level precoding matrix indication information and the RI;

Determining a second equivalent channel according to the first equivalent channel and the second level precoding matrix;

Determining a signal to interference and noise ratio SINR according to the second equivalent channel, the power of the interference signal, and the power of the noise signal;

The CQI is determined based on the SINR.

Optionally, the determining unit 702 is specifically configured to:

Determining all possible antenna port combinations within a range of values of the number of antenna ports, and determining a channel throughput or capacity between the terminal and the network device in all possible antenna port combinations The pilot signal of the terminal receives the Q antenna ports with the highest power, wherein the channel throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal is corresponding according to the possible antenna port combination. The channel estimate is determined.

Optionally, the determining unit 702 is specifically configured to:

Determine the Q antenna ports according to the following steps:

Step A: determining a value range of the number of antenna ports used for CSI measurement;

Step B, let k=1, T ₀ =0;

Step C: Calculate the throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal when selecting k antenna ports from the A antenna ports, and select the throughput or a combination of antenna ports having the largest capacity of the pilot signal of the terminal or the terminal;

Step D, if k < Q _max , then proceeds to step E, otherwise proceeds to step G, Q _max is the upper limit of the range of values, L ≤ Q _max ≤ A;

Step E, if T _k >T _k-1 , proceed to step F, otherwise, go to step G; wherein T _k is the throughput or capacity when the k antenna ports are selected from the A antenna ports The pilot signal of the terminal receives the throughput or capacity corresponding to the antenna port combination with the highest power receiving power or the pilot signal receiving power of the terminal, and T _k-1 is when _k-1 antenna ports are selected from the A antenna ports. a throughput or capacity corresponding to a throughput or capacity or an antenna port combination of the terminal having the highest received power of the pilot signal or a pilot signal received power of the terminal;

Step F, let k = k+1, and go to step C;

Step G: Determine an antenna port in the antenna port combination in which the currently determined throughput or capacity or the pilot signal receiving power of the terminal is the largest, as an antenna port for CSI measurement.

For the foregoing method flow, the embodiment of the present disclosure further provides a network device and a terminal. The specific content of the network device and the terminal may be implemented by referring to the foregoing method, and details are not described herein again.

As shown in FIG. 8, an embodiment of the present disclosure provides a network device, including:

The processor 800 is configured to read a program in the memory 820, and perform the following process: receiving channel state information CSI fed back by the terminal, where the CSI includes at least first level precoding matrix indication information, the first level The precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals, where the first level precoding matrix indication information is Q determined according to channel estimation values of the A antenna ports. After the antenna port is determined according to the Q antenna ports, L ≤ Q ≤ A, where L is the value of the rank indication RI used by the network device to send downlink data to the terminal, or L is the Determining, by the terminal, a channel rank indicating value of the RI; determining, according to the received CSI and a beamforming vector corresponding to the A antenna ports, a first level precoding matrix; according to the first level precoding matrix Determining a transmission precoding matrix;

The transceiver 810 is configured to receive and transmit data under the control of the processor 800.

Optionally, the CSI received by the transceiver 810 further includes one or a combination of the following information:

a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

RI;

The channel quality indicates the CQI.

Optionally, the processor 800 is specifically configured to:

The transmitting precoding matrix is determined according to the following formula:

Wherein, W is the precoding matrix, _{W. 1} is a first stage of the pre-coding matrix, V _L is the second level pre-coding matrix, the second stage pre-coding matrix by said second pre-coding stage The matrix indicates the matrix indicated by the information,

Is the power normalization factor.

Optionally, the processor 800 is further configured to:

Determining A antenna ports for transmitting pilot signals, corresponding transmit antennas for each antenna port, spatial beams, and resources for transmitting pilot signals, where each antenna port corresponds to one spatial beam;

Determining, for each of the A antenna ports, a beamforming vector of a spatial beam corresponding to each antenna port in a first dimension, and a beamforming vector in a second dimension, and according to the a beamforming vector in a first dimension and a beamforming vector in the second dimension determining a three-dimensional spatial beamforming vector of a beam corresponding to the antenna port;

The pilot signal is beamformed and transmitted in all or part of the transmit antenna based on the three-dimensional spatial beamforming vector of each of the A antenna ports and the resources used by the pilot signals.

Optionally, the processor 800 is specifically configured to:

According to the distribution of the terminal, the direction of the spatial beam corresponding to each antenna port, the number of beams in each direction, and the beam width are determined.

Wherein, in FIG. 8, the bus architecture can include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 800 and various circuits of memory represented by memory 820. 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. Transceiver 810 can be a plurality of components, including a transmitter and a transceiver, providing means for communicating with various other devices on a transmission medium. The processor 800 is responsible for managing the bus architecture and general processing, and the memory 820 can store data used by the processor 800 in performing operations.

As shown in FIG. 9, an embodiment of the present disclosure provides a terminal, including:

The processor 900 is configured to read a program in the memory 920, and perform the following process: performing channel estimation according to the received pilot signal to obtain channel estimation values of the A antenna ports, where the A antenna ports are network devices Transmitting A antenna ports of the pilot signal; determining Q antenna ports according to channel estimation values of the A antenna ports, where L≤Q≤A, L is the network design The value of the rank indicator RI used when the terminal sends the downlink data, or L is the value of the channel rank indicator RI determined by the terminal; and is used to determine the first level precoding according to the Q antenna ports. The matrix indicates information, and the channel state information CSI including the first level precoding matrix indication information is fed back to the network device, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting pilots. The index in the A antenna ports of the signal;

The transceiver 910 is configured to receive and transmit data under the control of the processor 900.

Optionally, the CSI fed back to the network device by the transceiver 910 further includes one or a combination of the following information:

a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

RI;

The channel quality indicates the CQI.

Optionally, the CQI is determined according to the following manner:

Determining, according to the first level precoding matrix indication information, a first equivalent channel formed by Q channel estimation values corresponding to the Q antenna ports;

Determining a second level precoding matrix according to the second level precoding matrix indication information and the RI;

Determining a second equivalent channel according to the first equivalent channel and the second level precoding matrix;

Determining a signal to interference and noise ratio SINR according to the second equivalent channel, the power of the interference signal, and the power of the noise signal;

The CQI is determined based on the SINR.

Optionally, the processor 900 is specifically configured to:

Determining all possible antenna port combinations within a range of values of the number of antenna ports, and determining a channel throughput or capacity between the terminal and the network device in all possible antenna port combinations The pilot signal of the terminal receives the Q antenna ports with the highest power, wherein the channel throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal is corresponding according to the possible antenna port combination. The channel estimate is determined.

Optionally, the processor 900 is specifically configured to:

Determine the Q antenna ports according to the following steps:

Step A: determining a value range of the number of antenna ports used for CSI measurement;

Step B, let k=1, T ₀ =0;

Step C: Calculate the throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal when selecting k antenna ports from the A antenna ports, and select the throughput or a combination of antenna ports having the largest capacity of the pilot signal of the terminal or the terminal;

Step D, if k < Q _max , then proceeds to step E, otherwise proceeds to step G, Q _max is the upper limit of the range of values, L ≤ Q _max ≤ A;

Step E, if T _k >T _k-1 , proceed to step F, otherwise, go to step G; wherein T _k is the throughput or capacity when the k antenna ports are selected from the A antenna ports The pilot signal of the terminal receives the throughput or capacity corresponding to the antenna port combination with the highest power receiving power or the pilot signal receiving power of the terminal, and T _k-1 is when _k-1 antenna ports are selected from the A antenna ports. a throughput or capacity corresponding to a throughput or capacity or an antenna port combination of the terminal having the highest received power of the pilot signal or a pilot signal received power of the terminal;

Step F, let k = k+1, and go to step C;

Step G: Determine an antenna port in the antenna port combination in which the currently determined throughput or capacity or the pilot signal receiving power of the terminal is the largest, as an antenna port for CSI measurement.

In FIG. 9, the bus architecture may include any number of interconnected buses and bridges, specifically linked by one or more processors represented by processor 900 and various circuits of memory represented by memory 920. 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. Transceiver 910 can be a plurality of components, including a transmitter and a receiver, providing means for communicating with various other devices on a transmission medium. For different user equipments, the user interface 930 may also be an interface capable of externally connecting the required devices, including but not limited to a keypad, a display, a speaker, a microphone, a joystick, and the like.

The processor 900 is responsible for managing the bus architecture and general processing, and the memory 920 can store data used by the processor 900 in performing operations.

In summary, according to the method provided by the embodiment of the present disclosure, the terminal selects at least one antenna port from the A antenna ports that send the pilot signal from the network device, which reduces the overhead of the CSI measurement pilot and ensures as much as possible. A certain CSI measurement accuracy simplifies system design. Usually terminal selection The number of selected antenna ports is much smaller than the number of large-scale antennas of the network equipment, so the CSI measurement pilot overhead can be reduced, and the terminal can also select multiple spatial beam directions and their optimal weighting coefficients to more accurately estimate the CSI. .

Those skilled in the art will appreciate that embodiments of the present disclosure can be provided as a method, system, or computer program product. Accordingly, the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware aspects. Moreover, the present disclosure may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) including computer usable program code.

The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. 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 changes and modifications can be made in the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present invention cover the modifications and the modifications

Claims (22)

1. A channel state information feedback method includes:

   The terminal performs channel estimation according to the received pilot signal, and obtains channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device;

   Determining, by the terminal, the Q antenna ports according to the channel estimation values of the A antenna ports, where L ≤ Q ≤ A, where L is the value of the rank indication RI used by the network device to send downlink data to the terminal Or, L is a value of the channel rank indication RI determined by the terminal;

   Determining, by the terminal, the first level precoding matrix indication information according to the Q antenna ports, and feeding back the channel state information CSI including the first level precoding matrix indication information to the network device, where the first level precoding The matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.
2. The method according to claim 1, wherein the CSI fed back to the network device by the terminal further comprises one or a combination of the following information:

   a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

   RI;

   Channel quality indication CQI; and

   The number Q of antenna ports selected by the terminal.
3. The method according to claim 1, wherein the CSI fed back to the network device by the terminal comprises a CQI, and the CQI is determined according to the following manner:

   Determining, according to the first level precoding matrix indication information, a first equivalent channel formed by Q channel estimation values corresponding to the Q antenna ports;

   Determining, by the second level precoding matrix indication information and the RI, a second level precoding matrix; wherein the second level precoding matrix indication information is used to indicate that the second level precoding matrix is in the second level codebook set index of;

   Determining a second equivalent channel according to the first equivalent channel and the second level precoding matrix;

   Determining a signal to interference and noise ratio SINR according to the second equivalent channel, the power of the interference signal, and the power of the noise signal;

   The CQI is determined based on the SINR.
4. The method according to any one of claims 1 to 3, wherein the terminal determines Q antenna ports according to channel estimation values of the A antenna ports, including:

   Determining, in a range of values of the number of antenna ports, all possible antenna port combinations, and determining, in the all possible antenna port combinations, a channel throughput between the terminal and the network device or a capacity or a Q antenna port with the highest received power of the pilot signal of the terminal, wherein a channel throughput or capacity corresponding to each possible antenna port combination or a pilot signal received power of the terminal according to the possible antenna The channel estimation value corresponding to the port combination is determined.
5. The method according to claim 4, wherein said terminal determines all possible antenna port combinations within a range of values of the number of antenna ports, and determines in said all possible antenna port combinations that said terminal is The channel throughput or capacity between the network devices or the Q antenna ports with the highest pilot signal receiving power of the terminal includes the following steps:

   Step A: determining a value range of the number of antenna ports used for CSI measurement;

   Step B, let k=1, T ₀ =0;

   Step C: Calculate the throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal when selecting k antenna ports from the A antenna ports, and select the throughput or a combination of antenna ports having the largest capacity of the pilot signal of the terminal or the terminal;

   Step D, if k < Q _max , then proceeds to step E, otherwise proceeds to step G, Q _max is the upper limit of the range of values, L ≤ Q _max ≤ A;

   Step E, if T _k >T _k-1 , proceed to step F, otherwise, go to step G; wherein T _k is the throughput or capacity when the k antenna ports are selected from the A antenna ports The pilot signal of the terminal receives the throughput or capacity corresponding to the antenna port combination with the highest power receiving power or the pilot signal receiving power of the terminal, and T _k-1 is when _k-1 antenna ports are selected from the A antenna ports. a throughput or capacity corresponding to a throughput or capacity or an antenna port combination of the terminal having the highest received power of the pilot signal or a pilot signal received power of the terminal;

   Step F, let k = k+1, and go to step C;

   Step G: Determine an antenna port in the antenna port combination in which the currently determined throughput or capacity or the pilot signal receiving power of the terminal is the largest, as an antenna port for CSI measurement.
6. A method for acquiring channel state information includes:

   The network device receives the channel state information CSI fed back by the terminal, where the CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting the pilot signal. An index of the A antenna ports, where the first level precoding matrix indication information is determined by the Q antenna ports determined by the terminal according to the channel estimation values of the A antenna ports, and L≤ Q ≤ A, L is the value of the rank indication RI used by the network device to send downlink data to the terminal, or L is the value of the channel rank indication RI determined by the terminal;

   Determining, by the network device, a first level precoding matrix according to the received CSI and a beamforming vector corresponding to the A antenna ports;

   The network device determines to transmit a precoding matrix according to the first level precoding matrix.
7. The method according to claim 6, wherein the CSI received by the network device further comprises one or a combination of the following information:

   a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

   RI;

   Channel quality indication CQI; and

   The number Q of antenna ports selected by the terminal.
8. The method according to claim 6 or 7, wherein the determining, by the network device, the transmit precoding matrix according to the first level precoding matrix comprises:

   The network device determines the transmit precoding matrix according to the following formula:

   

   Wherein, W is the precoding matrix, _{W. 1} is a first stage of the pre-coding matrix, V _L is the second level pre-coding matrix, the second stage pre-coding matrix by said second pre-coding stage The matrix indicates the matrix indicated by the information,

   

   Is the power normalization factor.
9. The method according to claim 6, wherein before the network device receives the CSI fed back by the terminal, the method further includes:

   The network device determines A antenna ports that transmit pilot signals, a transmit antenna corresponding to each antenna port, a spatial beam, and resources used to transmit pilot signals, where each antenna port pair Should be a spatial beam;

   Determining, by the network device, a beamforming vector of a spatial beam corresponding to each antenna port in a first dimension, and a beamforming vector in a second dimension, for each of the A antenna ports, And determining, according to the beamforming vector in the first dimension and the beamforming vector in the second dimension, a three-dimensional spatial beamforming vector of a beam corresponding to the antenna port;

   The network device performs beamforming on the three-dimensional spatial beamforming vector of each of the A antenna ports and resources used by the pilot signals, and transmits the pilot signals in all or part of the transmitting antennas.
10. The method of claim 9, wherein the network device determines a spatial beam corresponding to each antenna port, including:

    The network device determines the direction of the spatial beam corresponding to each antenna port, the number of beams in each direction, and the beam width according to the distribution of the terminal.
11. A terminal comprising:

    a channel estimation unit, configured to perform channel estimation according to the received pilot signal, to obtain channel estimation values of the A antenna ports, where the A antenna ports are A antenna ports for transmitting the pilot signals by the network device;

    a determining unit, configured to determine Q antenna ports according to channel estimation values of the A antenna ports, where L≤Q≤A, L is a rank indication RI used by the network device to send downlink data to the terminal Value, or L is the value of the channel rank indication RI determined by the terminal;

    a sending unit, configured to determine first stage precoding matrix indication information according to the Q antenna ports, and feed back channel state information CSI including the first level precoding matrix indication information to a network device, where the first level The precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that transmit the pilot signals.
12. The terminal according to claim 11, wherein the CSI fed back to the network device by the sending unit further comprises one or a combination of the following information:

    a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

    RI;

    Channel quality indication CQI; and

    The number Q of antenna ports selected by the terminal.
13. The terminal according to claim 11, wherein the CSI fed back to the network device by the sending unit includes a CQI, and the CQI is determined according to the following manner:

    Determining, according to the first level precoding matrix indication information, a first equivalent channel formed by Q channel estimation values corresponding to the Q antenna ports;

    Determining, by the second level precoding matrix indication information and the RI, a second level precoding matrix; the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set ;

    Determining a second equivalent channel according to the first equivalent channel and the second level precoding matrix;

    Determining a signal to interference and noise ratio SINR according to the second equivalent channel, the power of the interference signal, and the power of the noise signal;

    The CQI is determined based on the SINR.
14. The terminal according to any one of claims 11 to 13, wherein the determining unit is specifically configured to:

    Determining all possible antenna port combinations within a range of values of the number of antenna ports, and determining a channel throughput or capacity between the terminal and the network device in all possible antenna port combinations The pilot signal of the terminal receives the Q antenna ports with the highest power, wherein the channel throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal is corresponding according to the possible antenna port combination. The channel estimate is determined.
15. The terminal according to claim 14, wherein the determining unit is specifically configured to: determine Q antenna ports according to the following steps:

    Step A: determining a value range of the number of antenna ports used for CSI measurement;

    Step B, let k=1, T ₀ =0;

    Step C: Calculate the throughput or capacity corresponding to each possible antenna port combination or the pilot signal received power of the terminal when selecting k antenna ports from the A antenna ports, and select the throughput or a combination of antenna ports having the largest capacity of the pilot signal of the terminal or the terminal;

    Step D, if k < Q _max , then proceeds to step E, otherwise proceeds to step G, Q _max is the upper limit of the range of values, L ≤ Q _max ≤ A;

    Step E, if T _k >T _k-1 , proceed to step F, otherwise, go to step G; wherein T _k is the throughput or capacity when the k antenna ports are selected from the A antenna ports The pilot signal of the terminal receives the throughput or capacity corresponding to the antenna port combination with the highest power receiving power or the pilot signal receiving power of the terminal, and T _k-1 is when _k-1 antenna ports are selected from the A antenna ports. a throughput or capacity corresponding to a throughput or capacity or an antenna port combination of the terminal having the highest received power of the pilot signal or a pilot signal received power of the terminal;

    Step F, let k = k+1, and go to step C;

    Step G: Determine an antenna port in the antenna port combination in which the currently determined throughput or capacity or the pilot signal receiving power of the terminal is the largest, as an antenna port for CSI measurement.
16. A network device, including:

    a receiving unit, configured to receive channel state information CSI fed back by the terminal, where the CSI includes at least first stage precoding matrix indication information, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting An index in the A antenna ports of the frequency signal, where the first level precoding matrix indication information is determined by the Q antenna ports determined by the terminal according to the channel estimation values of the A antenna ports, according to the Q antenna ports. And L ≤ Q ≤ A, L is a value of a rank indication RI used by the network device to send downlink data to the terminal, or L is a value of a channel rank indication RI determined by the terminal;

    a first determining unit, configured to determine, according to the received CSI and a beamforming vector corresponding to the A antenna ports, a first level precoding matrix;

    And a second determining unit, configured to determine, according to the first level precoding matrix, a transmit precoding matrix.
17. The network device according to claim 16, wherein the CSI received by the receiving unit further comprises one or a combination of the following information:

    a second level precoding matrix indication information, where the second level precoding matrix indication information is used to indicate an index of the second level precoding matrix in the second level codebook set;

    RI;

    Channel quality indication CQI; and

    The number Q of antenna ports selected by the terminal.
18. The network device according to claim 16 or 17, wherein the second determining unit is specifically configured to:

    The transmitting precoding matrix is determined according to the following formula:

    

    Wherein, W is the precoding matrix, _{W. 1} is a first stage of the pre-coding matrix, V _L is the second level pre-coding matrix, the second stage pre-coding matrix by said second pre-coding stage The matrix indicates the matrix indicated by the information,

    

    Is the power normalization factor.
19. The network device according to claim 16, wherein before the receiving unit receives the CSI fed back by the terminal, the receiving unit is further configured to:

    Determining A antenna ports for transmitting pilot signals, corresponding transmit antennas for each antenna port, spatial beams, and resources for transmitting pilot signals, where each antenna port corresponds to one spatial beam;

    Determining, for each of the A antenna ports, a beamforming vector of a spatial beam corresponding to each antenna port in a first dimension, and a beamforming vector in a second dimension, and according to the a beamforming vector in a first dimension and a beamforming vector in the second dimension determining a three-dimensional spatial beamforming vector of a beam corresponding to the antenna port;

    The pilot signal is beamformed and transmitted in all or part of the transmit antenna based on the three-dimensional spatial beamforming vector of each of the A antenna ports and the resources used by the pilot signals.
20. The network device according to claim 19, wherein the first determining unit is specifically configured to:

    According to the distribution of the terminal, the direction of the spatial beam corresponding to each antenna port, the number of beams in each direction, and the beam width are determined.
21. A network device, including a processor, a memory, and a transceiver;

    The processor is configured to read a program in the memory, and perform the following process: receiving channel state information CSI fed back by the terminal, where the CSI includes at least first level precoding matrix indication information, where The first level precoding matrix indication information is used to indicate an index of the Q antenna ports in the A antenna ports that send the pilot signals, where the first level precoding matrix indicates that the information terminal is determined according to channel estimation values of the A antenna ports. After the Q antenna ports are determined according to the Q antenna ports, L ≤ Q ≤ A, where L is the value of the rank indication RI used by the network device to send downlink data to the terminal, or L The channel rank determined for the terminal indicates the value of the RI; And determining, according to the received CSI and a beamforming vector corresponding to the A antenna ports, a first level precoding matrix; determining, according to the first level precoding matrix, a transmitting precoding matrix;

    The transceiver is for receiving and transmitting data.
22. A terminal comprising a processor, a memory and a transceiver;

    The processor is configured to read a program in the memory, and perform the following process: performing channel estimation according to the received pilot signal to obtain channel estimation values of A antenna ports, where the A antenna ports are The network device sends the A antenna ports of the pilot signal; and is configured to determine Q antenna ports according to the channel estimation values of the A antenna ports, where L≤Q≤A, L is that the network device sends the terminal to the terminal The rank used in the downlink data indicates the value of the RI, or L is the value of the channel rank indicator RI determined by the terminal; and is used to determine the first-level precoding matrix indication information according to the Q antenna ports, and The channel state information CSI including the first level precoding matrix indication information is fed back to the network device, where the first level precoding matrix indication information is used to indicate that the Q antenna ports are transmitting A pilot port of the pilot signal. Index in

    The transceiver is for receiving and transmitting data.

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