CN107222249B - Method and device for acquiring channel state information - Google Patents

Abstract

The invention discloses a channel state information acquisition method, which comprises the following steps: selecting a first precoding codebook index PMI for each layer, and selecting an optimal second PMI for each layer according to a preset criterion according to the first PMI and the second PMI set of each layer; selecting an optimal first class PMI for each layer according to the optimal second class PMI of each layer and the first class PMI set according to a preset criterion; and selecting the first class PMI and the second class PMI which are most matched with the current channel from the optimal first class PMI and the optimal second class PMI of each layer according to a preset criterion, and taking the number of layers corresponding to the most matched first class PMI and the most matched second class PMI as the rank RI of the channel matrix. The invention also discloses a device for acquiring the channel state information.

Description

Method and device for acquiring channel state information

technical field

The present invention relates to the field of wireless communication, and in particular, to a method and device for acquiring channel state information.

Background technique

The fourth-generation mobile communication system adopts the Multi-Input Multi-Output (MIMO) technology to improve peak throughput, spectral efficiency and system capacity. In particular, closed-loop spatial multiplexing based on precoding codebooks can further improve system performance. The prerequisite for the implementation of closed-loop spatial multiplexing technology is that the transmitter obtains accurate channel state information (Channel Sate Information, CSI), and selects an appropriate number of layers and precoding codebooks to preprocess the transmitted signal according to the channel state information. In the Long Term Evolution (Long Term Evolution, LTE) and Long Term Evolution Advance (Long Term Evolution Advance, LTE-A) systems, the user equipment (User Equipment, UE) at the receiving end feeds back channel state information to the transmitting end, where the information includes the channel The rank indicator (RI) of the matrix, the precoding codebook index (Precoding Matrix Index, PMI), and the channel quality indicator (Channel Quality Indicator, CQI). The receiving end uses the pilot signal to obtain the channel coefficient matrix H, selects the RI and PMI that best match the current channel according to some optimal criterion, and calculates the CQI after using the RI and PMI. The conventional processing method is to traverse all RIs. and PMI, select the optimal RI and PMI according to a certain optimal criterion. The commonly used optimal criterion is the maximum channel capacity criterion or the minimum mean square error criterion. Then, the CQI is calculated based on the selected RI and PMI. Therefore, the code The number of books determines the computational complexity.

In LTE Release 8 and 9, the base station (eNodeB) at the transmitting end supports a maximum of 4 antenna ports, and each RI has a maximum of 16 codebooks. For specific codebooks, see TS 36.211v9.1.0, and in LTE-A Release In version 10, the base station supports up to 8 transmit antenna ports, and in order to improve performance, a two-level codebook is introduced. The so-called two-level codebook means that each precoding matrix is indexed by the first-level codebook (First PMI) i ₁ And the index of the second-level codebook (Second PMI) i ₂ is determined by two indexes. From the technical specification TS36.213v10.13.0, it can be seen that in the codebook of the 8-antenna port layer 1 and layer 2, the values of i ₁ and i ₂ are 0 to 15. Therefore, the number of codebooks in layers 1 and 2 is 256. The values of codebooks i ₁ and i ₂ in layer 3 are 0 to 3 and 0 to 15, respectively. Codebooks in layer 4 The values of i ₁ and i ₂ are 0 to 3 and 0 to 7, respectively, and the total number of codebooks for layers 3 and 4 are 64 and 32, respectively; in order to further improve the performance of the 4-antenna port, in version R12, the For the two-level codebook of 4-antenna ports, from the technical specification TS36.213v12.6.0, it can be known that in the newly introduced codebooks of layers 1 and 2 of 4-antenna ports, the values of i ₁ and i ₂ are both 0 to 15. Therefore, the number of codebooks for layers 1 and 2 of the 4-antenna port is also increased to 256, see TS 36.213 for specific codebooks. Therefore, if the method of selecting the optimal RI and PMI by traversing the RI and PMI is continued, each layer needs to calculate the channel capacity corresponding to the i ₁ ×i ₂ precoding matrices, and the calculation amount is huge.

Aiming at the problem that the calculation complexity of the PMI selection of the two-level codebook is large, the related art provides three PMI selection methods for the two-level codebook. In order to reduce the computational complexity, a simplified calculation method of selecting PMI by using the zero-forcing and minimum mean square error algorithm to calculate the signal-to-noise ratio and capacity is proposed. The second is to compress the number of channel matrices when selecting the first-level codebook, and traverse all the codebooks to use the capacity maximization criterion. When selecting the second-level codebook of the subband, the number of channel matrices is also compressed, and the maximum minimum Euclidean distance criterion is adopted. In the third type of first codebook selection, the channel matrix block, eigendecomposition and other steps are used, and the maximum sum of eigenvalues criterion is used, and the commonly used maximum channel capacity criterion, minimum mean square error criterion or Minimum bit error rate criterion, etc.

However, the prior art has the following problems: the first method cannot reduce the computational complexity of the PMI selection process to the greatest extent; the second and third methods adopt different methods to reduce the computational complexity, but when implemented in software and hardware, the second The level codebook selection cannot reuse the first level codebook selection module, that is, the implementation is complicated.

SUMMARY OF THE INVENTION

In view of this, the embodiments of the present invention are expected to provide a method and apparatus for acquiring channel state information, so as to reduce the complexity of calculation and implementation of the RI and PMI selection process.

A method for acquiring channel state information, the method comprising:

Selecting the first-type precoding codebook index PMI for each layer, and selecting the optimal second-type PMI for each layer according to a preset criterion according to the first-type PMI and the second-type PMI set of each layer;

According to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to the preset criterion;

According to the preset criteria, the first-type PMI and the second-type PMI that best match the current channel are selected from the optimal first-type PMI and the optimal second-type PMI of each layer, and the best matching The number of layers corresponding to the first type PMI and the second type PMI is taken as the rank RI of the channel matrix.

Wherein, the first type of precoding codebook index PMI is selected for each layer, and the optimal PMI is selected for each layer according to the set of the first type of PMI and the second type of PMI for each layer according to a preset criterion Before the second type of PMI, the method further includes: using the pilot signal to estimate and obtain a channel coefficient matrix and a noise variance matrix on each subcarrier.

Wherein, the first type of precoding codebook index PMI is selected for each layer, and the optimal first type of precoding codebook index PMI is selected for each layer according to the set of the first type of PMI and the second type of PMI according to preset criteria for each layer. Category II PMIs include:

randomly select a first-type PMI for the selected layer from the first-type PMI set of the selected layer;

According to the channel coefficient matrix and the noise variance matrix, calculate the channel capacity 1 when the selected precoding matrix 1 of the selected layer is used on each subcarrier, and the selected precoding matrix 1 of the selected layer is determined by the selected precoding matrix 1 a precoding matrix indicated by a second-type PMI in the first-type PMI and the second-type PMI set of the layer;

Accumulate the channel capacity 1 of each subcarrier to obtain the channel capacity 2 when the selected precoding matrix of the selected layer is used on the entire bandwidth;

Compare the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and take the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the optimal second PMI of the selected layer. Class PMI.

Wherein, selecting the optimal first-type PMI for each layer according to the optimal second-type PMI and the first-type PMI set for each layer according to the preset criteria, including:

According to the channel coefficient matrix and the noise variance matrix, calculate the channel capacity 3 when the selected precoding matrix 2 of the selected layer is used on each subcarrier, and the selected precoding matrix 2 of the selected layer is determined by the selected layer. The optimal second type PMI and a precoding matrix indicated by a first type PMI in the first type PMI set;

Accumulate the channel capacity 3 of each subcarrier to obtain the channel capacity 4 when the selected precoding matrix 2 of the selected layer is used on the entire bandwidth;

Comparing the channel capacity 4 corresponding to each precoding matrix 2 of the selected layer, and taking the first type PMI of the precoding matrix 2 corresponding to the maximum channel capacity 4 as the optimal first PMI of the selected layer Class PMI.

Wherein, according to the preset criteria, the first type PMI and the second type PMI that best match the current channel are selected from the optimal first type PMI and the optimal second type PMI of each layer, and the The number of layers corresponding to the most matching first-type PMI and second-type PMI is used as the rank RI of the channel matrix, including:

Read the channel capacity when using the precoding matrix of the selected layer over the entire bandwidth, the precoding matrix of the selected layer is indicated by the optimal first type PMI and the optimal second type PMI for the selected layer precoding matrix;

Compare the channel capacity of each layer, and take the optimal first-type PMI and the optimal second-type PMI of the precoding matrix corresponding to the maximum channel capacity as the first-type PMI and the second-type PMI that best match the current channel , and the number of layers corresponding to the most matched first-type PMI and second-type PMI is used as the rank RI of the channel matrix.

The first type of PMI is an index of a second-level codebook, and the second-type PMI is an index of a first-level codebook.

An apparatus for acquiring channel state information, the apparatus comprising:

The first selection module is used to select the first type of precoding codebook index PMI for each layer, and select the first type of PMI and the second type of PMI set for each layer according to preset criteria for each layer. The optimal second-type PMI; according to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to the preset criterion;

The second selection module is configured to select the first-type PMI and the second-type PMI that best match the current channel from the optimal first-type PMI and the optimal second-type PMI of each layer according to the preset criterion , and the number of layers corresponding to the most matched first-type PMI and second-type PMI is used as the rank RI of the channel matrix.

Wherein, the apparatus further includes: an estimation module for selecting the first type of precoding codebook index PMI for each layer, and according to the set of the first type PMI and the second type PMI of each layer according to The preset criterion is that before selecting the optimal second-type PMI for each layer, the channel coefficient matrix and the noise variance matrix on each subcarrier are estimated by using the pilot signal.

Wherein, the first selection module includes:

A selection module, configured to randomly select a first-type PMI for the selected layer from the first-type PMI set of the selected layer;

The capacity calculation module is used to calculate the channel capacity 1 when the selected precoding matrix 1 of the selected layer is used on each subcarrier according to the channel coefficient matrix and the noise variance matrix, and the selected precoding matrix 1 of the selected layer is used. is a precoding matrix indicated by a second-type PMI in the first-type PMI and second-type PMI set for the selected layer;

A capacity accumulating module, configured to accumulate the channel capacity 1 of each subcarrier to obtain the channel capacity 2 when the selected precoding matrix of the selected layer is used in the entire bandwidth;

A comparison module, configured to compare the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and use the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the selected layer The optimal second-class PMI.

Wherein, the apparatus further includes: a reporting module configured to report the rank RI of the channel matrix and the first-type PMI and the second-type PMI that best match the current channel.

The first type of PMI is an index of a second-level codebook, and the second-type PMI is an index of a first-level codebook.

In a method and device for acquiring channel state information provided by an embodiment of the present invention, a first type of precoding codebook index PMI is selected for each layer, and according to a set of the first type of PMI and the second type of PMI of each layer, a preset The criterion is to select the optimal second-type PMI for each layer; according to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to the preset criteria; Suppose the criterion selects the first type PMI and the second type PMI that best match the current channel from the optimal first type PMI and the optimal second type PMI of each layer, and selects the best matching first type PMI and second type PMI. The number of layers corresponding to the class PMI is used as the rank RI of the channel matrix. In this way, by separately selecting the index of the first-level codebook and the index of the second-level codebook, the computational complexity of the selection process of RI and PMI can be reduced; The index and the index of the optimal second-level codebook are selected using the same criterion, which can reduce the implementation complexity of the RI and PMI selection process.

Description of drawings

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

FIG. 2 is a schematic structural diagram 1 of an apparatus for obtaining channel state information according to an embodiment of the present invention;

FIG. 3 is a second schematic structural diagram of an apparatus for obtaining channel state information according to an embodiment of the present invention;

4 is a schematic flowchart of a specific embodiment 1 of a method for acquiring channel state information provided by the present invention;

5 is a schematic flowchart of a specific embodiment 2 of a method for acquiring channel state information provided by the present invention;

FIG. 6 is a schematic flowchart of Embodiment 3 of a method for acquiring channel state information provided by the present invention;

FIG. 7 is a schematic flowchart of Embodiment 4 of a method for acquiring channel state information provided by the present invention.

Detailed ways

In the embodiment of the present invention, the terminal selects the first-type precoding codebook index PMI for each layer, and selects the first-type PMI and the second-type PMI set for each layer according to a preset criterion for each layer The optimal second-type PMI; the terminal selects the optimal first-type PMI for each layer according to the preset criteria according to the optimal second-type PMI of each layer and the first-type PMI set; the terminal selects the optimal first-type PMI from each layer according to the preset criteria From the optimal first-type PMI and the optimal second-type PMI, select the first-type PMI and the second-type PMI that best match the current channel, and assign the layers corresponding to the best-matching first-type PMI and second-type PMI number as the rank RI of the channel matrix.

The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a schematic flowchart of a method for obtaining channel state information according to an embodiment of the present invention. As shown in FIG. 1 , the method includes:

Step 101: Select the first-type precoding codebook index PMI for each layer, and select the optimal second-type PMI for each layer according to the set of the first-type PMI and the second-type PMI for each layer according to a preset criterion PMI.

Specifically, in this step, the terminal randomly selects a first-type precoding codebook index PMI for each layer, and according to the set of the first-type PMI and the second-type PMI of each layer, according to a preset criterion for each layer The layer selects the optimal second-class PMI.

The terminal is a receiver device relative to the transmitter base station, such as a mobile phone or a mobile data card. The mobile data card refers to a Subscriber Identity Module (SIM) that provides wireless Internet access for portable devices such as computers.

Specifically, the first type of PMI may be an index of a second-level codebook, that is, Second PMI, and the second-type PMI may be an index of a first-level codebook, that is, First PMI. Specifically, this step may be that the terminal randomly selects a Second PMI for each layer from the SecondPMI set of each layer, and according to the Second PMI and First PMI set of each layer according to a preset criterion, selects a second PMI from each layer from each layer. Select the optimal First PMI for each layer in the First PMI set of . That is, in this step, the index of the optimal first-level codebook of each layer is selected first, and then the index of the optimal second-level codebook of each layer is selected according to the subsequent steps.

Certainly, the first type of PMI is either First PMI, and the second type of PMI is either Second PMI. Specifically, this step may be that the terminal randomly selects a First PMI for each layer from the First PMI set of each layer, and selects a First PMI for each layer from the set of First PMI and Second PMI of each layer according to a preset criterion, from each layer The optimal Second PMI is selected for each layer in the Second PMI set of the layer. That is, in this step, the index of the optimal second-level codebook of each layer is selected first, and then the index of the optimal first-level codebook of each layer is selected according to the subsequent steps.

It should be noted that, since the First PMI represents the long-term or slow-changing characteristics of the channel, and the Second PMI represents the short-term or fast-changing characteristics of the channel, the communication system performance of selecting the index of the codebook according to the latter order , the performance of the communication system such as throughput, bit error rate, etc. is worse than that of the communication system that selects the codebook index according to the previous order; therefore, in the scenario where better communication system performance is expected, the previous A sequential selection codebook index.

Specifically, the preset criterion may be a maximum channel capacity criterion. Of course, the preset criterion is either the minimum mean square error criterion or the minimum bit error rate criterion.

It should be noted that, when the preset criterion is the maximum channel capacity criterion, before this step, the method for obtaining the channel state information provided by the embodiment of the present invention may further include: the terminal uses the pilot signal to estimate and obtain the channel state information on each subcarrier. Channel coefficient matrix and noise variance matrix.

其中，For example, take the MIMO system with 8 antenna ports at the transmitter and 4 antennas at the receiver as an example, and assume that all codebooks in the codebook subset limit configured by the high layer are available; for an 8×4 MIMO system, the terminal uses cell guidance The channel coefficient matrix on the kth subcarrier obtained by estimation of the frequency signal (Cell Reference Signal, CRS) or the channel state information pilot signal (Channel State Information Reference Signal, CSI-RS) is denoted as H _k and the noise variance matrix is denoted as

in,

h _ij represents the channel coefficient from the j-th transmit antenna port to the i-th receive antenna, σ ² is the noise power, and I ₄ is a 4×4 identity matrix.

Specifically, when the preset criterion is the maximum channel capacity criterion, this step may include: the terminal randomly selects a first-type PMI for the selected layer from the first-type PMI set of the selected layer; the terminal selects a first-type PMI for the selected layer according to the channel coefficient matrix and noise variance matrix, calculate the channel capacity 1 when using the selected precoding matrix 1 of the selected layer on each subcarrier, and the selected precoding matrix 1 of the selected layer is the first random selected by the selected layer. The precoding matrix indicated by the class PMI and a class 2 PMI in the set of class 2 PMIs; the terminal accumulates the channel capacity of each subcarrier to obtain the channel capacity of the entire bandwidth when the precoding matrix of the selected layer is used 2. The terminal compares the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and takes the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the optimal second type PMI of the selected layer.

Specifically, still taking the above-mentioned 8×4 MIMO system as an example, the First PMI is denoted as i ₁ , the Second PMI is denoted as i ₂ , the i ₁ set is denoted as Ω ₁ , and the i ₂ set is denoted as Ω ₂ , and the preset criterion is The maximum channel capacity criterion, when the first type of PMI is Second PMI, and the second type of PMI is First PMI, the above process may include:

The terminal randomly selects a Second PMI for the first layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the first layer, denoted as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤15} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (15, i' ₂ ) indication on the entire bandwidth is obtained The channel capacity 2 when the precoding matrix is set; the terminal compares the 16 channel capacity 2 of the first layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal First PMI of the first layer, and records the optimal First PMI as i” ₁₁ ;

The terminal randomly selects a Second PMI for the second layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the second layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤15} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (15, i' ₂ ) indication on the entire bandwidth is obtained The channel capacity 2 when the precoding matrix is set; the terminal compares the 16 channel capacity 2 of the second layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal First PMI of the second layer, and records the optimal First PMI as i” ₁₂ ;

The terminal randomly selects a Second PMI for the third layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the third layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤3} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (3, i' ₂ ) indication on the entire bandwidth is obtained The channel capacity 2 when the precoding matrix is set; the terminal compares the 4 channel capacity 2 of the third layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal First PMI of the third layer, and records the optimal First PMI as i” ₁₃ ;

The terminal randomly selects a Second PMI for the fourth layer from Ω ₂ ={i ₂ |0≤i ₂ ≤7} of the fourth layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤3} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (3, i' ₂ ) indication on the entire bandwidth is obtained channel capacity 2 when the precoding matrix of i” ₁₄ .

Wherein, when the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (i ₁ , i' ₂ ) on each subcarrier, the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。where C represents the channel capacity, W is the precoding matrix indicated by (i ₁ , i' ₂ ), W ^H is the conjugate transpose matrix of W, H _k is the channel coefficient matrix on the kth subcarrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Among them, the terminal compares the channel capacity 2 of the nth layer, and selects the optimal First PMIi" _1n , and the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。In the formula, i" _1n represents the optimal First PMI of the nth layer, W is the precoding matrix indicated by (i ₁ , i' ₂ ), W ^H is the conjugate transpose matrix of W, and H _k is the k-th sub the matrix of channel coefficients on the carrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Specifically, still taking the above-mentioned 8×4 MIMO system as an example, the First PMI is denoted as i ₁ , the Second PMI is denoted as i ₂ , the i ₁ set is denoted as Ω ₁ , and the i ₂ set is denoted as Ω ₂ , and the preset criterion is When the maximum channel capacity criterion is used, and the first type of PMI is the First PMI and the second type of PMI is the Second PMI, the specific process for implementing this step is similar to the above-mentioned process, and details are not repeated here.

It should be noted that, when the preset criterion is the minimum mean square error criterion, this step may include: the terminal randomly selects a first-type PMI for the selected layer from the first-type PMI set of the selected layer; the terminal calculates the entire The mean square error when using the selected precoding matrix one of the selected layer over the bandwidth, where the selected precoding matrix one of the selected layer is randomly selected by the selected layer in the first type PMI and the second type PMI set A precoding matrix indicated by a second type PMI; the terminal compares the mean square error corresponding to each precoding matrix one of the selected layer, and uses the second type PMI of the precoding matrix one corresponding to the minimum mean square error as the selected layer The optimal second-class PMI.

It should be noted that, when the preset criterion is the minimum bit error rate criterion, this step may include: the terminal randomly selects a first-type PMI for the selected layer from the first-type PMI set of the selected layer; Bit error rate or block error rate when using the selected precoding matrix one of the selected layer over the bandwidth, and the selected precoding matrix one of the selected layer is the first type PMI and the second type PMI randomly selected by the selected layer. A precoding matrix indicated by a second-type PMI in the set of class PMIs; The second-type PMI of encoding matrix one is taken as the optimal second-type PMI for the selected layer.

Specifically, the terminal acquiring the bit error rate or block error rate of the selected precoding matrix one of the selected layer over the entire bandwidth may include: the terminal calculating the product of the channel coefficient matrix over the bandwidth and the selected precoding matrix one ; According to the product result and the noise variance estimation value on the bandwidth, the terminal searches the preset table to obtain the bit error rate or block error rate of the selected precoding matrix using the selected layer on the bandwidth temporarily.

The preset table corresponds to the product of the channel coefficient matrix on the bandwidth and the selected precoding matrix one, and the noise variance estimate value on the bandwidth, and stores the error of using the selected precoding matrix one of the selected layer on the bandwidth. Bit rate or block error rate. In practical applications, the bit error rate or block error rate in the preset table can be obtained through simulation.

Step 102: According to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to a preset criterion.

Specifically, this step may be that the terminal selects the optimal first-type PMI for each layer according to the optimal second-type PMI and the first-type PMI set for each layer according to a preset criterion.

Specifically, when the first type of PMI is the Second PMI and the second type of PMI is the First PMI, this step may be that the terminal selects each layer according to the optimal First PMI and the Second PMI set of each layer according to a preset criterion Optimal SecondPMI.

Specifically, when the first type of PMI is the First PMI and the second type of PMI is the Second PMI, this step may be that the terminal selects for each layer according to the set of the optimal Second PMI and the First PMI of each layer according to a preset criterion Optimal FirstPMI.

It should be noted that, when the preset criterion is the maximum channel capacity criterion, this step may include that the terminal calculates, according to the channel coefficient matrix and the noise variance matrix, the channel when the selected precoding matrix 2 of the selected layer is used on each subcarrier. Capacity 3, the selected precoding matrix 2 of the selected layer is a precoding matrix indicated by the optimal second-type PMI of the selected layer and a first-type PMI in the first-type PMI set; The channel capacity 3 of the carrier is accumulated to obtain the channel capacity 4 when the selected precoding matrix 2 of the selected layer is used in the entire bandwidth; the terminal compares the channel capacity 4 corresponding to each precoding matrix 2 of the selected layer, and the maximum channel The first-type PMI of precoding matrix two corresponding to capacity four is taken as the optimal first-type PMI of the selected layer.

Specifically, still taking the above-mentioned 8×4 MIMO system as an example, the First PMI is denoted as i ₁ , the Second PMI is denoted as i ₂ , the i ₁ set is denoted as Ω ₁ , and the i ₂ set is denoted as Ω ₂ , and the preset criterion is When the maximum channel capacity criterion is used, and the first type of PMI is SecondPMI and the second type of PMI is First PMI, the above process may include:

获得i”₁₁；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₁，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₁，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₁，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₁，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₁，15)指示的预编码矩阵时的信道容量四；终端比较第一层的16个信道容量四，将最大信道容量四对应的SecondPMI作为第一层的最优Second PMI，并将该最优Second PMI记为i”₂₁；The terminal reads the optimal of the first layer

Obtain i"₁₁; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₁ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₁ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₁ on each subcarrier , 1) the channel capacity three when the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₁ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₁ , 15) is used on the entire bandwidth is obtained; the terminal compares the 16 channel capacity 4 of the first layer, and takes the SecondPMI corresponding to the maximum channel capacity 4 as the second PMI. the optimal Second PMI of one layer, and denote the optimal Second PMI as i"₂₁;

获得i”₁₂；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₂，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₂，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₂，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₂，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₂，15)指示的预编码矩阵时的信道容量四；终端比较第二层的16个信道容量四，将最大信道容量四对应的SecondPMI作为第二层的最优Second PMI，并将该最优Second PMI记为i”₂₂；The terminal reads the optimal of the second layer

Obtain i"₁₂; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₂ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₂ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₂ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₂ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₂ , 15) is used on the entire bandwidth is obtained; The optimal Second PMI of the second floor, and this optimal Second PMI is denoted as i"₂₂;

获得i”₁₃；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₃，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₃，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₃，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₃，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₃，15)指示的预编码矩阵时的信道容量四；终端比较第三层的16个信道容量四，将最大信道容量四对应的Second PMI作为第三层的最优Second PMI，并将该最优Second PMI记为i”₂₃；The terminal reads the optimal of the third layer

Obtain i"₁₃; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₃ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₃ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₃ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₃ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₃ , 15) is used on the entire bandwidth is obtained; the terminal compares the 16 channel capacity 4 of the third layer, and takes the Second PMI corresponding to the maximum channel capacity 4 as The optimal Second PMI of the third layer, and this optimal Second PMI is denoted as i"₂₃;

获得i”₁₄；终端遍历Ω₂＝{i₂|0≤i₂≤7}中每一个值；终端计算每个子载波上使用索引(i”₁₄，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₄，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₄，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₄，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₄，15)指示的预编码矩阵时的信道容量四；终端比较第四层的8个信道容量四，将最大信道容量四对应的Second PMI作为第四层的最优Second PMI，并将该最优Second PMI记为i”₂₄。The terminal reads the optimal of the fourth layer

Obtain i"₁₄; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤7}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₄ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₄ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₄ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₄ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when using the precoding matrix indicated by (i" ₁₄ , 15) on the entire bandwidth is obtained; The optimal Second PMI of the fourth layer, and the optimal Second PMI is denoted as i” ₂₄ .

Wherein, when the terminal calculates the channel capacity three when using the precoding matrix indicated by the index (i" _1n , i ₂ ) on each subcarrier, the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。where C represents the channel capacity, W is the precoding matrix indicated by (i” _1n , i ₂ ), W ^H is the conjugate transpose matrix of W, H _k is the channel coefficient matrix on the kth subcarrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Among them, the terminal compares the channel capacity of the nth layer, and selects the optimal Second PMIi” _2n . The formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。In the formula, i” _2n represents the optimal Second PMI of the nth layer, W is the precoding matrix indicated by (i” _1n , i ₂ ), W ^H is the conjugate transpose matrix of W, and H _k is the k-th sub the matrix of channel coefficients on the carrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Specifically, still taking the above-mentioned 8×4 MIMO system as an example, the First PMI is denoted as i ₁ , the Second PMI is denoted as i ₂ , the i ₁ set is denoted as Ω ₁ , and the i ₂ set is denoted as Ω ₂ , and the preset criterion is When the maximum channel capacity criterion is used, and the first type of PMI is the First PMI and the second type of PMI is the Second PMI, the specific process for implementing this step is similar to the above-mentioned process, and details are not repeated here.

It should be noted that, when the preset criterion is the minimum mean square error criterion, this step may include: the terminal calculates the mean square error when the selected precoding matrix 2 of the selected layer is used over the entire bandwidth, and the The selected precoding matrix 2 is a precoding matrix indicated by the optimal second-type PMI of the selected layer and a first-type PMI in the first-type PMI set; the terminal compares the corresponding precoding matrix 2 of the selected layer. The mean square error of , the first type PMI of the precoding matrix 2 corresponding to the minimum mean square error is taken as the optimal first type PMI of the selected layer.

It should be noted that, when the preset criterion is the minimum bit error rate criterion, this step may include that the terminal obtains the bit error rate or block error rate when the selected precoding matrix 2 of the selected layer is used over the entire bandwidth, and the The second selected precoding matrix of the selected layer is a precoding matrix indicated by the optimal second type PMI of the selected layer and one first type PMI in the first type PMI set; the terminal compares each precoding matrix of the selected layer. For the bit error rate or block error rate corresponding to the coding matrix 2, the first type PMI of the precoding matrix 2 corresponding to the minimum bit error rate is taken as the optimal first type PMI of the selected layer.

Specifically, the terminal acquires the bit error rate or block error rate when the selected precoding matrix 2 of the selected layer is used over the entire bandwidth, and the above-mentioned terminal acquires the selected precoding matrix using the selected layer over the entire bandwidth. The temporary bit error rate or block error rate process is similar and will not be repeated here.

Step 103: Select the first-type PMI and the second-type PMI that best match the current channel from the optimal first-type PMI and the optimal second-type PMI of each layer according to the preset criteria, The number of layers corresponding to one type of PMI and the second type of PMI is used as the rank RI of the channel matrix.

Specifically, this step may be that the terminal selects the first-type PMI and the second-type PMI that best match the current channel from the optimal first-type PMI and the optimal second-type PMI of each layer according to a preset criterion, and The number of layers corresponding to the most matching first-type PMI and second-type PMI is taken as the rank RI of the channel matrix.

It should be noted that, when the preset criterion is the maximum channel capacity criterion, this step may include: the terminal reads the channel capacity when the precoding matrix of the selected layer is used over the entire bandwidth, and the precoding matrix of the selected layer is: The precoding matrix indicated by the optimal first-type PMI and the optimal second-type PMI of the selected layer; the terminal compares the channel capacity of each layer, and assigns the optimal first-type PMI of the precoding matrix corresponding to the maximum channel capacity and the optimal second-type PMI as the first-type PMI and the second-type PMI that best match the current channel, and the number of layers corresponding to the best-matched first-type PMI and the second-type PMI as the rank RI of the channel matrix.

Specifically, still taking the above-mentioned 8×4 MIMO system as an example, the First PMI is denoted as i ₁ , the Second PMI is denoted as i ₂ , the i ₁ set is denoted as Ω ₁ , and the i ₂ set is denoted as Ω ₂ , and the preset criterion is When the maximum channel capacity criterion is used, the above process may include:

The terminal reads from the calculation result in step 102 the channel capacity when using the precoding matrix indicated by (i" ₁₁ , i" ₂₁ ) over the entire bandwidth; the terminal reads the calculation result in step 102 to use (i" ₁₂ , i" ₂₂ ) indicates the channel capacity of the precoding matrix; the terminal reads from the calculation result in step 102 the channel capacity when the precoding matrix indicated by (i" ₁₃ , i" ₂₃ ) is used on the entire bandwidth; the terminal The channel capacity when the precoding matrix indicated by (i" ₁₄ , i" ₂₄ ) is used on the entire bandwidth is read from the calculation result in step 102; The optimal first-type PMI and the optimal second-type PMI are used as the first-type PMI and the second-type PMI that best match the current channel, and the number of layers corresponding to the best-matched first-type PMI and the second-type PMI is used as the channel The rank RI of the matrix.

It should be noted that when the preset criterion is the minimum mean square error criterion, this step may include: the terminal calculates the mean square error when the precoding matrix of the selected layer is used over the entire bandwidth, and the precoding matrix of the selected layer is used. is the precoding matrix indicated by the optimal first-type PMI and the optimal second-type PMI of the selected layer; the terminal compares the mean square error of each layer, and assigns the optimal first type of the precoding matrix corresponding to the minimum mean square error The class PMI and the optimal second class PMI are taken as the first class PMI and the second class PMI that best match the current channel, and the number of layers corresponding to the best matched first class PMI and the second class PMI is taken as the rank of the channel matrix RI.

It should be noted that, when the preset criterion is the minimum bit error rate criterion, this step may include that the terminal obtains the bit error rate or block error rate when using the precoding matrix of the selected layer over the entire bandwidth, and the selected layer The precoding matrix is the precoding matrix indicated by the optimal first type PMI and the optimal second type PMI of the selected layer; the terminal compares the bit error rate or block error rate of each layer, and assigns the minimum bit error rate or error The optimal first-type PMI and the optimal second-type PMI of the precoding matrix corresponding to the block rate are taken as the first-type PMI and the second-type PMI that best match the current channel, and the best-matched first-type PMI and second-type PMI are used. The number of layers corresponding to the second type of PMI is used as the rank RI of the channel matrix.

Specifically, the terminal obtains the bit error rate or block error rate when the precoding matrix of the selected layer is used over the entire bandwidth, which is the same as the above-mentioned error when the terminal obtains the selected precoding matrix of the selected layer over the entire bandwidth. The bit rate or block error rate process is similar and will not be repeated here.

In this way, the index of the first-level codebook and the index of the second-level codebook are selected separately, and each layer only needs to calculate the channel capacity, mean square error or bit error rate corresponding to the i ₁ +i ₂ precoding matrices. The RI and PMI are obtained, avoiding the need to calculate the channel capacity, mean square error or bit error rate corresponding to the i ₁ ×i ₂ precoding matrices to select the PMI, thereby reducing the computational complexity of the RI and PMI selection process. At the same time, because the same criterion is adopted when selecting the index of the optimal first-level codebook and the index of the optimal second-level codebook in the present invention, the calculation method is consistent, and the same module can be time-division multiplexed to realize the selection. The index of the optimal first-level codebook and the index of the optimal second-level codebook are obtained, which reduces the scale of software and hardware, thereby reducing the implementation complexity of the RI and PMI selection process.

It should be noted that, the method for acquiring channel state information provided by the embodiment of the present invention may further include: the terminal reporting the rank RI of the channel matrix and the first type PMI and the second type PMI that best match the current channel.

In order to realize the above method, the present invention discloses a channel state information acquisition device.

FIG. 2 is a schematic structural diagram 1 of an apparatus for obtaining channel state information according to an embodiment of the present invention. As shown in FIG. 2 , the transmit power detection apparatus includes:

The first selection module 202A is configured to select the first-type precoding codebook index PMI for each layer, and select the first-type PMI and the second-type PMI set for each layer according to a preset criterion for each layer. Obtain the optimal second-type PMI; select the optimal first-type PMI for each layer according to the optimal second-type PMI and the first-type PMI set for each layer according to the preset criteria;

The second selection module 202B is configured to select the first-type PMI and the second-type PMI that best match the current channel from the optimal first-type PMI and the optimal second-type PMI of each layer according to the preset criterion PMI, and the number of layers corresponding to the most matched first-type PMI and second-type PMI is used as the rank RI of the channel matrix.

Further, as shown in FIG. 3 , the apparatus further includes: an estimation module 201, configured to select a first type of precoding codebook index PMI for each layer, and based on the first type of PMI of each layer And before selecting the optimal second-type PMI set for each layer according to a preset criterion, the channel coefficient matrix and the noise variance matrix on each subcarrier are obtained by using the pilot signal estimation.

Further, as shown in FIG. 3 , the first selection module 202A includes:

A selection module 2021, configured to randomly select a first-type PMI for the selected layer from the first-type PMI set of the selected layer;

The capacity calculation module 2022 is used to calculate the channel capacity 1 when the selected precoding matrix of the selected layer is used on each subcarrier according to the channel coefficient matrix and the noise variance matrix, and the selected precoding matrix of the selected layer is used. one is a precoding matrix indicated by a second type PMI in the set of first type PMI and second type PMI for the selected layer;

A capacity accumulation module 2023, configured to accumulate the channel capacity 1 of each subcarrier to obtain the channel capacity 2 when the selected precoding matrix of the selected layer is used on the entire bandwidth;

A comparison module 2024, configured to compare the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and use the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the selected layer The optimal second-class PMI for the layer.

Further, as shown in Figure 3, the device further includes:

A reporting module 203, configured to report the rank RI of the channel matrix and the first-type PMI and the second-type PMI that best match the current channel.

Further, the first-type PMI is an index of the second-level codebook, and the second-type PMI is an index of the first-level codebook.

In practical applications, the estimation module 201, the first selection module 202A, the second selection module 202B, and the reporting module 203 can all be composed of a central processing unit (Central Processing Unit, CPU), a microprocessor (MicroProcessor Unit, MPU), digital signal processor (Digital Signal Processor, DSP), or Field Programmable Gate Array (Field Programmable Gate Array, FPGA) and other implementations.

FIG. 4 is a schematic flowchart of a specific embodiment 1 of a method for obtaining channel state information provided by the present invention. As shown in FIG. 4 , a MIMO system of the R11 version with 8 antenna ports at the transmitting end and 4 antennas at the receiving end is used as an example, and it is assumed that All codebooks in the codebook subset limit configured by the high layer are available, and the specific steps include:

Step 401: Use the cell pilot signal CRS or the channel state information pilot signal CSI-RS to estimate and obtain the channel coefficient matrix and the noise variance matrix on each subcarrier.

Specifically, in this step, the terminal uses the cell pilot signal CRS or the channel state information pilot signal CSI-RS to estimate and obtain the channel coefficient matrix and the noise variance matrix on each subcarrier.

其中，Among them, the channel coefficient matrix on the kth subcarrier estimated by the terminal is denoted as H _k and the noise variance matrix is denoted as

in,

h _ij represents the channel coefficient from the j-th transmit antenna port to the i-th receive antenna, σ ² is the noise power, and I ₄ is a 4×4 identity matrix.

Step 402: Randomly select a Second PMI for each layer from the Second PMI set of each layer, and according to the Second PMI and First PMI set of each layer, according to the maximum channel capacity criterion, from the First PMI set of each layer Select the optimal First PMI for each layer.

Specifically, this step may be that the terminal randomly selects a Second PMI for each layer from the Second PMI set of each layer, and according to the Second PMI and First PMI set of each layer, according to the maximum channel capacity criterion, from each layer The optimal First PMI is selected for each layer in the First PMI set of one layer.

Specifically, this step may include: the terminal randomly selects a Second PMI for the first layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the first layer, and denotes it as i'₂; the terminal traverses Ω ₁ = Each value in {i ₁ |0≤i ₁ ≤15}; the terminal calculates the channel capacity one when using the precoding matrix indicated by index (0, i' ₂ ) on each subcarrier; Channel capacity 1 is accumulated to obtain channel capacity 2 when the precoding matrix indicated by (0, i' ₂ ) is used on the entire bandwidth; when the terminal calculates the precoding matrix indicated by index (1, i' ₂ ) on each subcarrier, the Channel capacity 1; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth; and so on, until the entire bandwidth is obtained. (15, i' ₂ ) indicates the channel capacity 2 of the precoding matrix; the terminal compares the 16 channel capacity 2 of the first layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal FirstPMI of the first layer, and uses the The optimal First PMI is denoted as i"₁₁;

The terminal randomly selects a Second PMI for the second layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the second layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤15} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (15, i' ₂ ) indication on the entire bandwidth is obtained The channel capacity 2 when the precoding matrix is set; the terminal compares the 16 channel capacity 2 of the second layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal First PMI of the second layer, and records the optimal First PMI as i” ₁₂ ;

The terminal randomly selects a Second PMI for the third layer from Ω ₂ ={i ₂ |0≤i ₂ ≤15} of the third layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤3} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (3, i' ₂ ) indication on the entire bandwidth is obtained The channel capacity 2 when the precoding matrix is set; the terminal compares the 4 channel capacity 2 of the third layer, takes the First PMI corresponding to the maximum channel capacity 2 as the optimal First PMI of the third layer, and records the optimal First PMI as i” ₁₃ ;

The terminal randomly selects a Second PMI for the fourth layer from Ω ₂ ={i ₂ |0≤i ₂ ≤7} of the fourth layer and denote it as i'₂; the terminal traverses Ω ₁ ={i ₁ |0≤i ₁ ≤3} each value; the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (0, i' ₂ ) on each subcarrier; the terminal accumulates the channel capacity 1 on each subcarrier to obtain the entire bandwidth Channel capacity two when using the precoding matrix indicated by (0, i' ₂ ) on the terminal; the terminal calculates the channel capacity one when using the precoding matrix indicated by the index (1, i' ₂ ) on each subcarrier; Once the channel capacity on the carrier is accumulated, the channel capacity 2 when the precoding matrix indicated by (1, i' ₂ ) is used on the entire bandwidth is obtained; and so on, until the (3, i' ₂ ) indication on the entire bandwidth is obtained channel capacity 2 when the precoding matrix of i” ₁₄ .

Wherein, when the terminal calculates the channel capacity 1 when using the precoding matrix indicated by the index (i ₁ , i' ₂ ) on each subcarrier, the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。where C represents the channel capacity, W is the precoding matrix indicated by (i ₁ , i' ₂ ), W ^H is the conjugate transpose matrix of W, H _k is the channel coefficient matrix on the kth subcarrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Among them, the terminal compares the channel capacity 2 of the nth layer, and selects the optimal First PMIi" _1n , and the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。In the formula, i" _1n represents the optimal First PMI of the nth layer, W is the precoding matrix indicated by (i ₁ , i' ₂ ), W ^H is the conjugate transpose matrix of W, and H _k is the k-th sub the matrix of channel coefficients on the carrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Step 403: According to the optimal First PMI and Second PMI set of each layer, select the optimal Second PMI for each layer according to the maximum channel capacity criterion.

Specifically, this step may be that the terminal selects the optimal Second PMI for each layer according to a preset criterion according to the optimal First PMI and Second PMI set of each layer.

获得i”₁₁；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₁，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₁，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₁，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₁，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₁，15)指示的预编码矩阵时的信道容量四；终端比较第一层的16个信道容量四，将最大信道容量四对应的Second PMI作为第一层的最优Second PMI，并将该最优Second PMI记为i”₂₁；Specifically, this step may include: the terminal reads the optimal value of the first layer

Obtain i"₁₁; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₁ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₁ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₁ on each subcarrier , 1) the channel capacity three when the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₁ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₁ , 15) is used in the entire bandwidth is obtained; the optimal Second PMI of the first layer, and denote the optimal Second PMI as i"₂₁;

获得i”₁₂；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₂，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₂，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₂，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₂，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₂，15)指示的预编码矩阵时的信道容量四；终端比较第二层的16个信道容量四，将最大信道容量四对应的SecondPMI作为第二层的最优Second PMI，并将该最优Second PMI记为i”₂₂；The terminal reads the optimal of the second layer

Obtain i"₁₂; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₂ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₂ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₂ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₂ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₂ , 15) is used on the entire bandwidth is obtained; The optimal Second PMI of the second floor, and this optimal Second PMI is denoted as i"₂₂;

获得i”₁₃；终端遍历Ω₂＝{i₂|0≤i₂≤15}中每一个值；终端计算每个子载波上使用索引(i”₁₃，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₃，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₃，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₃，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₃，15)指示的预编码矩阵时的信道容量四；终端比较第三层的16个信道容量四，将最大信道容量四对应的SecondPMI作为第三层的最优Second PMI，并将该最优Second PMI记为i”₂₃；The terminal reads the optimal of the third layer

Obtain i"₁₃; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤15}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₃ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₃ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₃ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₃ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when the precoding matrix indicated by (i" ₁₃ , 15) is used on the whole bandwidth is obtained; The optimal Second PMI of the three layers, and this optimal Second PMI is denoted as i"₂₃;

获得i”₁₄；终端遍历Ω₂＝{i₂|0≤i₂≤7}中每一个值；终端计算每个子载波上使用索引(i”₁₄，0)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₄，0)指示的预编码矩阵时的信道容量四；终端计算每个子载波上使用索引(i”₁₄，1)指示的预编码矩阵时的信道容量三；终端将每个子载波上的该信道容量三累加，获得整个带宽上使用(i”₁₄，1)指示的预编码矩阵时的信道容量四；以此类推，直至获得整个带宽上使用(i”₁₄，15)指示的预编码矩阵时的信道容量四；终端比较第四层的8个信道容量四，将最大信道容量四对应的Second PMI作为第四层的最优Second PMI，并将该最优Second PMI记为i”₂₄。The terminal reads the optimal of the fourth layer

Obtain i"₁₄; the terminal traverses each value in Ω ₂ ={i ₂ |0≤i ₂ ≤7}; the terminal calculates the channel capacity when using the precoding matrix indicated by the index (i" ₁₄ , 0) on each subcarrier Three; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₄ , 0) on the entire bandwidth; the terminal calculates the use index (i" ₁₄ on each subcarrier , 1) the channel capacity three during the indicated precoding matrix; the terminal accumulates the channel capacity three on each subcarrier to obtain the channel capacity four when using the precoding matrix indicated by (i" ₁₄ , 1) on the entire bandwidth; And so on, until the channel capacity 4 when using the precoding matrix indicated by (i" ₁₄ , 15) on the entire bandwidth is obtained; The optimal Second PMI of the fourth layer, and the optimal Second PMI is denoted as i” ₂₄ .

Wherein, when the terminal calculates the channel capacity three when using the precoding matrix indicated by the index (i" _1n , i ₂ ) on each subcarrier, the formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。where C represents the channel capacity, W is the precoding matrix indicated by (i” _1n , i ₂ ), W ^H is the conjugate transpose matrix of W, H _k is the channel coefficient matrix on the kth subcarrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Among them, the terminal compares the channel capacity of the nth layer, and selects the optimal Second PMIi” _2n . The formula used is as follows:

为H_k的共轭转置矩阵，

为第k个子载波上的噪声方差估计值，I为单位阵，在上述例子中I＝I₄。In the formula, i” _2n represents the optimal Second PMI of the nth layer, W is the precoding matrix indicated by (i” _1n , i ₂ ), W ^H is the conjugate transpose matrix of W, and H _k is the k-th sub the matrix of channel coefficients on the carrier,

is the conjugate transpose matrix of H _k ,

is the estimated value of the noise variance on the kth subcarrier, I is the identity matrix, and I=I ₄ in the above example.

Step 404: Select the First PMI and Second PMI that best match the current channel from the optimal First PMI and the second PMI of each layer according to the maximum channel capacity, and assign the number of layers corresponding to the best matching First PMI and Second PMI Rank RI as the channel matrix.

Specifically, this step may be that the terminal selects the First PMI and Second PMI that best match the current channel from the optimal First PMI and the optimal Second PMI of each layer according to the maximum channel capacity, and uses the best matching First PMI and Second PMI The number of layers corresponding to the PMI is used as the rank RI of the channel matrix.

Specifically, this step may include: the terminal reads out the channel capacity when the precoding matrix indicated by (i" ₁₁ , i" ₂₁ ) is used over the entire bandwidth from the calculation result in step 403; Read out the channel capacity when the _precoding matrix indicated by (i” ₁₂ , i” _{22 )} is used over the entire bandwidth; The channel capacity when the indicated precoding matrix is used; the terminal reads from the calculation result in step 403 the channel capacity when using the precoding matrix indicated by (i” ₁₄ , i” ₂₄ ) on the entire bandwidth; the terminal compares the 4 channel capacities , take the optimal First PMI and the optimal Second PMI of the precoding matrix corresponding to the maximum channel capacity as the First PMI and Second PMI that best match the current channel, and take the number of layers corresponding to the best matching First PMI and Second PMI as the channel The rank RI of the matrix.

FIG. 5 is a schematic flowchart of a specific embodiment 2 of a method for obtaining channel state information provided by the present invention. As shown in FIG. 5 , a MIMO system with 8 antenna ports at the transmitting end and 4 antennas at the receiving end of the R11 version is taken as an example, and it is assumed that All codebooks in the codebook subset limit configured by the high layer are available, and the specific steps include:

Step 501: Use the cell pilot signal CRS or the channel state information pilot signal CSI-RS to estimate and obtain the channel coefficient matrix and the noise variance matrix on each subcarrier.

Specifically, in this step, the terminal uses the cell pilot signal CRS or the channel state information pilot signal CSI-RS to estimate and obtain the channel coefficient matrix and the noise variance matrix on each subcarrier.

其中，Among them, the channel coefficient matrix on the kth subcarrier estimated by the terminal is denoted as H _k and the noise variance matrix is denoted as

in,

h _ij represents the channel coefficient from the j-th transmit antenna port to the i-th receive antenna, σ ² is the noise power, and I ₄ is a 4×4 identity matrix.

Step 502: Randomly select a First PMI for each layer from the First PMI set of each layer, and according to the First PMI and Second PMI set of each layer, according to the maximum channel capacity criterion, from the Second PMI set of each layer Select the optimal Second PMII for each layer.

Specifically, this step may be that the terminal randomly selects a First PMI for each layer from the First PMI set of each layer, and according to the First PMI and Second PMI set of each layer, according to the maximum channel capacity criterion, from each layer The optimal Second PMII is selected for each layer in the Second PMI set of one layer.

Step 503: According to the optimal Second PMI and First PMI sets of each layer, select the optimal First PMI for each layer according to the maximum channel capacity criterion.

Specifically, this step may be that the terminal selects the optimal First PMI for each layer according to the set of the optimal Second PMI and the First PMI of each layer according to the maximum channel capacity criterion.

Step 504: Select the First PMI and Second PMI that best match the current channel from the optimal First PMI and the optimal Second PMI of each layer according to the maximum channel capacity, and assign the number of layers corresponding to the best matching First PMI and Second PMI Rank RI as the channel matrix.

Specifically, this step may be that the terminal selects the First PMI and Second PMI that best match the current channel from the optimal First PMI and the optimal Second PMI of each layer according to the maximum channel capacity, and uses the best matching First PMI and Second PMI The number of layers corresponding to the PMI is used as the rank RI of the channel matrix.

Specifically, this step may include: the terminal reads the channel capacity when the precoding matrix indicated by (i" ₁₁ , i" ₂₁ ) is used over the entire bandwidth from the calculation result of step 503; Read out the channel capacity when the _precoding matrix indicated by (i” ₁₂ , i” _{22 )} is used over the entire bandwidth; The channel capacity when the indicated precoding matrix is used; the terminal reads out the channel capacity when the precoding matrix indicated by (i” ₁₄ , i” ₂₄ ) is used on the entire bandwidth from the calculation result in step 503; the terminal compares the 4 channel capacities , take the optimal First PMI and the optimal Second PMI of the precoding matrix corresponding to the maximum channel capacity as the First PMI and Second PMI that best match the current channel, and take the number of layers corresponding to the best matching First PMI and Second PMI as the channel The rank RI of the matrix.

FIG. 6 is a schematic flowchart of a specific embodiment 3 of a method for acquiring channel state information provided by the present invention. As shown in FIG. 6 , the specific steps include:

Step 601: Randomly select a first-type precoding codebook index PMI for each layer, and select the most precoding codebook index PMI for each layer according to the set of the first-type PMI and the second-type PMI for each layer according to the minimum mean square error criterion. Excellent Class II PMI.

Specifically, in this step, the terminal randomly selects a first-type precoding codebook index PMI for each layer, and according to the set of the first-type PMI and the second-type PMI of each layer, according to the minimum mean square error criterion: The optimal second-class PMI is selected for each layer.

Specifically, this step may include: the terminal randomly selects a first-type PMI for the selected layer from the first-type PMI set of the selected layer; mean square error, the selected precoding matrix one of the selected layer is a precoding matrix indicated by a first-type PMI randomly selected by the selected layer and a second-type PMI in the second-type PMI set; the terminal compares The mean square error corresponding to each precoding matrix 1 of the selected layer, and the second type PMI of the precoding matrix 1 corresponding to the minimum mean square error is taken as the optimal second type PMI of the selected layer.

Step 602: According to the optimal second-type PMI and the first-type PMI set of each layer, select the optimal first-type PMI for each layer according to the minimum mean square error criterion.

Specifically, this step may be that the terminal selects the optimal first-type PMI for each layer according to the optimal second-type PMI and the first-type PMI set according to the minimum mean square error criterion for each layer.

Specifically, this step may include: the terminal calculates the mean square error when using the selected precoding matrix 2 of the selected layer over the entire bandwidth, and the selected precoding matrix 2 of the selected layer is determined by the optimal precoding matrix of the selected layer. The second type of PMI and the precoding matrix indicated by the first type of PMI in the first type of PMI set; the terminal compares the mean square error corresponding to each precoding matrix of the selected layer The first-type PMI of matrix two is taken as the optimal first-type PMI for the selected layer.

Step 603: According to the minimum mean square error criterion, the first type PMI and the second type PMI that best match the current channel are selected from the optimal first type PMI and the optimal second type PMI of each layer, and the most matching type PMI and the second type PMI are selected. The number of layers corresponding to the first type PMI and the second type PMI is taken as the rank RI of the channel matrix.

Specifically, this step may be that the terminal selects the first type PMI and the second type PMI that best match the current channel from the optimal first type PMI and the optimal second type PMI of each layer according to the minimum mean square error criterion , and the number of layers corresponding to the most matching first-type PMI and second-type PMI is used as the rank RI of the channel matrix.

Specifically, this step may include that the terminal calculates the mean square error when using the precoding matrix of the selected layer over the entire bandwidth, where the precoding matrix of the selected layer is determined by the optimal first-type PMI and the most optimal PMI of the selected layer. The precoding matrix indicated by the second type PMI is preferred; the terminal compares the mean square error of each layer, and takes the optimal first type PMI and the optimal second type PMI of the precoding matrix corresponding to the minimum mean square error as the most relevant to the current channel. The matched first-type PMI and the second-type PMI, and the number of layers corresponding to the most matched first-type PMI and the second-type PMI is used as the rank RI of the channel matrix.

FIG. 7 is a schematic flowchart of Embodiment 4 of a method for acquiring channel state information provided by the present invention. As shown in FIG. 7 , the specific steps include:

Step 701: Randomly select a first-type precoding codebook index PMI for each layer, and select the highest-level precoding codebook index PMI for each layer according to the set of the first-type PMI and the second-type PMI for each layer according to the minimum bit error rate criterion. Excellent Class II PMI.

Specifically, in this step, the terminal randomly selects a first-type precoding codebook index PMI for each layer, and according to the set of the first-type PMI and the second-type PMI of each layer, according to the minimum bit error rate criterion: The optimal second-type PMI is selected for each layer.

Specifically, this step may include: the terminal randomly selects a first-type PMI for the selected layer from the first-type PMI set of the selected layer; Bit error rate or block error rate, the selected precoding matrix 1 of the selected layer is the precoding indicated by the first type PMI and the second type PMI in the set of the first type PMI and the second type PMI randomly selected by the selected layer. Matrix; the terminal compares the bit error rate or block error rate corresponding to each precoding matrix 1 of the selected layer, and takes the second type PMI of the precoding matrix 1 corresponding to the minimum bit error rate or block error rate as the maximum value of the selected layer. Excellent Class II PMI.

Specifically, the terminal acquiring the bit error rate or block error rate of the selected precoding matrix one of the selected layer over the entire bandwidth may include: the terminal calculating the product of the channel coefficient matrix over the bandwidth and the selected precoding matrix one ; According to the product result and the noise variance estimation value on the bandwidth, the terminal searches the preset table to obtain the bit error rate or block error rate of the selected precoding matrix using the selected layer on the bandwidth temporarily.

The preset table corresponds to the product of the channel coefficient matrix on the bandwidth and the selected precoding matrix one, and the noise variance estimate value on the bandwidth, and stores the error of using the selected precoding matrix one of the selected layer on the bandwidth. Bit rate or block error rate. In practical applications, the bit error rate or block error rate in the preset table can be obtained through simulation.

Step 702: According to the optimal second-type PMI and the first-type PMI set of each layer, select the optimal first-type PMI for each layer according to the minimum bit error rate criterion.

Specifically, this step may be that the terminal selects the optimal first-type PMI for each layer according to the optimal second-type PMI and the first-type PMI set for each layer according to the minimum bit error rate criterion.

Specifically, this step may include that the terminal obtains the bit error rate or block error rate when using the selected precoding matrix 2 of the selected layer over the entire bandwidth, and the selected precoding matrix 2 of the selected layer is selected by The optimal second-type PMI of the layer and the precoding matrix indicated by a first-type PMI in the first-type PMI set; the terminal compares the bit error rate or block error rate corresponding to each precoding matrix two of the selected layer, and uses The first-type PMI of precoding matrix 2 corresponding to the minimum bit error rate or block error rate is taken as the optimal first-type PMI of the selected layer.

Specifically, the terminal acquires the bit error rate or block error rate when the selected precoding matrix 2 of the selected layer is used over the entire bandwidth, and the above-mentioned terminal acquires the selected precoding matrix using the selected layer over the entire bandwidth. The temporary bit error rate or block error rate process is similar and will not be repeated here.

Step 703: Select the first type PMI and the second type PMI that best match the current channel from the optimal first type PMI and the optimal second type PMI of each layer according to the minimum bit error rate criterion, and use the best matching The number of layers corresponding to the first type PMI and the second type PMI is taken as the rank RI of the channel matrix.

Specifically, this step may be that the terminal selects the first type PMI and the second type PMI that best match the current channel from the optimal first type PMI and the optimal second type PMI of each layer according to the minimum bit error rate criterion , and the number of layers corresponding to the most matching first-type PMI and second-type PMI is used as the rank RI of the channel matrix.

Specifically, this step may include that the terminal obtains the bit error rate or block error rate when using the precoding matrix of the selected layer over the entire bandwidth, and the precoding matrix of the selected layer is determined by the optimal first layer of the selected layer. The precoding matrix indicated by the class PMI and the optimal second class PMI; the terminal compares the bit error rate or block error rate of each layer, and compares the optimal first class PMI and the optimal first class PMI of the precoding matrix corresponding to the minimum bit error rate. The second-type PMI is used as the first-type PMI and the second-type PMI that best match the current channel, and the number of layers corresponding to the first-type PMI and the second-type PMI that best match is used as the rank RI of the channel matrix.

Specifically, the terminal obtains the bit error rate or block error rate when the precoding matrix of the selected layer is used over the entire bandwidth, and the above-mentioned terminal obtains the error when the selected precoding matrix of the selected layer is used over the entire bandwidth. The bit rate or block error rate process is similar and will not be repeated here.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes, and the protection scope of the present invention is subject to the claims.

Claims (11)

1. A method for acquiring channel state information, wherein the method comprises: Selecting the first-type precoding codebook index PMI for each layer, and selecting the optimal second-type PMI for each layer according to a preset criterion according to the first-type PMI and the second-type PMI set of each layer; According to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to the preset criterion; According to the preset criteria, the first-type PMI and the second-type PMI that best match the current channel are selected from the optimal first-type PMI and the optimal second-type PMI of each layer, and the best matching The number of layers corresponding to the first type PMI and the second type PMI is taken as the rank RI of the channel matrix. 2 . The method according to claim 1 , wherein a first type of precoding codebook index PMI is selected for each layer, and according to the first type of PMI and the second type of PMI of each layer. 3 . Before the set selects the optimal second-type PMI for each layer according to a preset criterion, the method further includes: The channel coefficient matrix and the noise variance matrix on each sub-carrier are estimated by using the pilot signal. 3. The method according to claim 1, wherein the first type of precoding codebook index PMI is selected for each layer, and the first type of PMI and the second type of PMI are set according to the first type of PMI and the second type of PMI for each layer. The optimal second-type PMI is selected for each layer according to preset criteria, including: randomly select a first-type PMI for the selected layer from the first-type PMI set of the selected layer; According to the channel coefficient matrix and the noise variance matrix, calculate the channel capacity 1 when the selected precoding matrix 1 of the selected layer is used on each subcarrier, and the selected precoding matrix 1 of the selected layer is determined by the selected precoding matrix 1 a precoding matrix indicated by a second-type PMI in the first-type PMI and the second-type PMI set of the layer; Accumulate the channel capacity 1 of each subcarrier to obtain the channel capacity 2 when the selected precoding matrix of the selected layer is used on the entire bandwidth; Compare the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and take the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the optimal second PMI of the selected layer. Class PMI. 4. The method according to claim 1, wherein the optimal second-type PMI and the first-type PMI set for each layer are selected according to the preset criteria for each layer. Category 1 PMI, including: According to the channel coefficient matrix and the noise variance matrix, calculate the channel capacity 3 when the selected precoding matrix 2 of the selected layer is used on each subcarrier, and the selected precoding matrix 2 of the selected layer is determined by the selected layer. The optimal second type PMI and a precoding matrix indicated by a first type PMI in the first type PMI set; Accumulate the channel capacity 3 of each subcarrier to obtain the channel capacity 4 when the selected precoding matrix 2 of the selected layer is used on the entire bandwidth; Comparing the channel capacity 4 corresponding to each precoding matrix 2 of the selected layer, and taking the first type PMI of the precoding matrix 2 corresponding to the maximum channel capacity 4 as the optimal first PMI of the selected layer Class PMI. 5 . The method according to claim 1 , wherein, according to the preset criterion, the optimal first-type PMI and the optimal second-type PMI of each layer are selected to best match the current channel. 6 . The first type PMI and the second type PMI, and the number of layers corresponding to the most matching first type PMI and the second type PMI is used as the rank RI of the channel matrix, including: Read the channel capacity when using the precoding matrix of the selected layer over the entire bandwidth, the precoding matrix of the selected layer is indicated by the optimal first type PMI and the optimal second type PMI for the selected layer precoding matrix; Compare the channel capacity of each layer, and take the optimal first-type PMI and the optimal second-type PMI of the precoding matrix corresponding to the maximum channel capacity as the first-type PMI and the second-type PMI that best match the current channel , and the number of layers corresponding to the most matched first-type PMI and second-type PMI is used as the rank RI of the channel matrix. 6 . The method according to claim 1 , wherein the first-type PMI is an index of a second-level codebook, and the second-type PMI is an index of a first-level codebook. 7 . 7. An apparatus for acquiring channel state information, wherein the apparatus comprises: A first selection module, configured to select the first type of precoding codebook index PMI for each layer, and select the first type of PMI and the second type of PMI set for each layer according to a preset criterion for each layer the optimal second-type PMI; according to the optimal second-type PMI and the first-type PMI set of each layer, the optimal first-type PMI is selected for each layer according to the preset criterion; The second selection module is configured to select the first-type PMI and the second-type PMI that best match the current channel from the optimal first-type PMI and the optimal second-type PMI of each layer according to the preset criterion , and the number of layers corresponding to the most matched first-type PMI and second-type PMI is used as the rank RI of the channel matrix. 8. The apparatus according to claim 7, wherein the apparatus further comprises: an estimation module, configured to select the first type of precoding codebook index PMI for each layer, Before selecting the optimal second-type PMI for each layer according to the preset criteria, the first-type PMI and the second-type PMI set use pilot signal estimation to obtain the channel coefficient matrix and the noise variance matrix on each subcarrier. 9. The apparatus according to claim 7, wherein the first selection module comprises: A selection module, configured to randomly select a first-type PMI for the selected layer from the first-type PMI set of the selected layer; The capacity calculation module is used to calculate the channel capacity 1 when the selected precoding matrix 1 of the selected layer is used on each subcarrier according to the channel coefficient matrix and the noise variance matrix, and the selected precoding matrix 1 of the selected layer is used. is a precoding matrix indicated by a second-type PMI in the first-type PMI and second-type PMI set for the selected layer; A capacity accumulating module, configured to accumulate the channel capacity 1 of each subcarrier to obtain the channel capacity 2 when the selected precoding matrix of the selected layer is used in the entire bandwidth; A comparison module, configured to compare the channel capacity 2 corresponding to each precoding matrix 1 of the selected layer, and use the second type PMI of the precoding matrix 1 corresponding to the maximum channel capacity 2 as the selected layer The optimal second-class PMI. 10. The apparatus of claim 7, wherein the apparatus further comprises: A reporting module, configured to report the rank RI of the channel matrix and the first type PMI and the second type PMI that best match the current channel. The apparatus according to claim 7, wherein the first-type PMI is an index of a second-level codebook, and the second-type PMI is an index of a first-level codebook.

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