CN102025404A - Codebook generation method and device - Google Patents

Abstract

The invention provides a codebook generation method and device. The method comprises the following steps: acquiring an initial codebook set and feeding back; and determining to modify the initial codebook at real time according to channel performance information obtained from estimation. Seen from the codebook modification-based adaptive codebook generation method that on the basis of not changing the existing codebook basis matrix, a group of new codebook modification matrixes are generated according to the performance statistical property of a system, feedback expenditure is considered to modify the initial codebook set, and codebook accuracy is adjusted timely according to the real-time change of the channel, so that the codebook capacity is expanded and the codebook accuracy is improved under the condition of increasing little feedback expenditure, thereby more effectively improving precoding performance in the case of limited feedback.

Description

A kind of method for generating codebooks and device

Technical field

The present invention relates to multiple-input and multiple-output (MIMO, Multiple Input Multiple Output) technology, refer to especially under a kind of Limited Feedback condition, based on the method for generating codebooks and the device of precoding.

Background technology

In mimo system, introduce precoding and can obtain the bigger power system capacity and the availability of frequency spectrum of Geng Gao.Yet the realization of precoding is a condition based on transmitting terminal known channel state information (CSI, Chancel StateInformation) all generally.At symmetrical time division duplex (TDD, Time Double Division) in the system, reception and emission hocket, this moment, receiving terminal also was a transmitting terminal, if the transformation time that receives and launch is less than the coherence time of channel, then the estimated channel state information can be used for next x time to sending the preliminary treatment of signal when receiving.But, when forward link in the system and reverse link are asymmetric such as Frequency Division Duplexing (FDD) (FDD, Frequency Double Division) system just need quantize channel parameter or beam shaping vector etc., to adapt to the band-limited actual conditions of feedback channel.

In order to reduce feedback information volume, relatively one of effective method is precoding (or beam shaping) scheme that adopts based on matrix (or vector) code book, is called the limited feedback precoding method.The limited feedback precoding method roughly comprises: design one group of pre-coding matrix or beam vector of optimizing according to channel statistic property earlier, constitute a code book, this code book is all known at transmitting terminal and receiving terminal; Receiving terminal selects a code word in the code book to be used as transmitting terminal pre-coding matrix or beam shaping vector according to estimated channel matrix and certain performance criteria, and its sequence number in code book is fed back to transmitting terminal.

The design of code book is very crucial in the design of a MIMO pre-coding system link, and method for designing and various code word that a lot of documents have also provided various precoding codebooks are chosen criterion.In the 3G standard evolution process, own through being adopted as alternative based on the transmission precoding MIMO technology of code book.

Two topmost problems that need to solve in the code book design are: how quantized channel space, the i.e. problem of design codebooks collection; And how the recipient selects the problem of current code book according near principle.Complement each other in these two question essences, designed code book collection receiving terminal and could select the current code book that needs feedback according near principle; And had just near principle, just can design optimum code book collection.

Solve above two problems, from the angle of vector quantization, key point is exactly to design suitable quantitative criteria.With the same, also need design standard based on the precoding design of partial information based on the precoding of complete information design.Corresponding with it, design standard mainly contains two big classes, the volumetric(al) standards and the error rate (BER, Bit Error Rate) standard.But any standard no matter, between expense of feeding back and performance, a contradiction can be arranged all, therefore, to the code book design and be the hot issue that research institution is studied at this field to the influence of the mode of the mode of precoding and feedback thus always.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of method for generating codebooks, can improve the performance of precoding under the situation of Limited Feedback effectively.

Another object of the present invention is to provide a kind of code book generating apparatus, can under the situation of Limited Feedback, improve the performance of precoding effectively.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of method for generating codebooks comprises:

Obtain initial codebook set and feedback;

According to the channel performance information of estimating to obtain, decision is revised in real time to initial codebook.

Described channel performance is Signal to Interference plus Noise Ratio SINR; Described estimation channel performance information is:

At each code stream, its SINR is shown in the following formula:

${\mathrm{SINR}}_i\left(n\right)=\frac{{\left|\right|H_i{V}_i\left(n\right)\left|\right|}^2}{{\mathrm{\σ}}_i^2+\underset{k=1,k\≠i}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_i{V}_k\left|\right|}^2+{\left|\right|H_i{V}_i(:)\left|\right|}^2};$

Wherein, SINR _i(n) SINR of n code stream of i user of expression, H _iWith

Be respectively i user's channel matrix and noise power, V _i(n) be precoding codebook vector, V at n code stream of user i _i(:) is the precoding codebook vector of user i except that n code stream, V _kBe the precoding codebook vector of interference user, K is the number of all interference users.

Described decision is modified in real time to initial codebook:

Described SINR value between any two code streams does not satisfy | SINR _i(n)-SINR _i(m) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows adopts correction matrix P, according to following formula described initial codebook set is revised:

$\tilde{V}={\mathrm{VP}}^k$ k＝0，1，2，…N _t-1，

Wherein, V is original initial codebook set, and P is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas, Be revised new code book set;

Correction matrix

The order of wherein supposing channel matrix is n.

Described decision is modified in real time to initial codebook:

Described SINR value between any two code streams does not satisfy | SINR _i(n)-SINR _i(m) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows is carried out balance to the SINR on each road.

Described SINR to each road carries out balance and comprises:

For order is 2 situation, and modification method is shown below:

$\tilde{V}=V\left[\begin{array}{cc}\sin \left(\mathrm{\θ}\right)& 0\\ 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$ Wherein θ is a selectable angle, and span is 0≤θ＜pi/2;

Greater than 2 situation, modification method is shown below for order:

$\tilde{V}=V\left[\begin{array}{ccccc}\sin \left(\mathrm{\θ}\right)& 0& \mathrm{\Λ}& 0& 0\\ 0& \sin \left(\mathrm{\θ}\right)+\mathrm{\Δ}& \mathrm{\Λ}& 0& 0\\ 0& 0& \mathrm{\Λ}& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$

Wherein, the increment factor Δ satisfies Be an adjustable factors, θ is a selectable angle, and span is 0≤θ＜pi/2;

V is original initial codebook set,

Be revised new code book set.

Described channel performance is a signal to noise ratio snr.

Described decision is modified in real time to initial codebook:

Described SNR value between any two code streams does not satisfy | SNR _i(n)-SNR _i(m) | during≤ε ', wherein, ε ' is a default smaller value, and the energy difference between any two code streams that expression allows adopts correction matrix P, according to following formula described initial codebook set is revised:

$\tilde{V}={\mathrm{VP}}^k$ k＝0，1，2，…N _t-1，

Wherein, V is original initial codebook set, and P is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas, Be revised new code book set;

Correction matrix

The order of wherein supposing channel matrix is n.

Described decision is modified in real time to initial codebook:

Described SINR value between any two code streams does not satisfy | SINR _i(n)-SINR _i(m) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows is carried out balance to the SINR on each road;

Described SINR to each road carries out balance and comprises:

For order is 2 situation, and modification method is shown below:

$\tilde{V}=V\left[\begin{array}{cc}\sin \left(\mathrm{\θ}\right)& 0\\ 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$ Wherein θ is a selectable angle, and span is 0≤θ＜pi/2;

Greater than 2 situation, modification method is shown below for order:

$\tilde{V}=V\left[\begin{array}{ccccc}\sin \left(\mathrm{\θ}\right)& 0& \mathrm{\Λ}& 0& 0\\ 0& \sin \left(\mathrm{\θ}\right)+\mathrm{\Δ}& \mathrm{\Λ}& 0& 0\\ 0& 0& \mathrm{\Λ}& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$

Wherein, the increment factor Δ satisfies

Be an adjustable factors, θ is a selectable angle, and span is 0≤θ＜pi/2;

V is original initial codebook set,

Be revised new code book set.

Described channel performance is an error rate BER;

Described decision is modified in real time to initial codebook:

When the described system BER that estimates is higher than the threshold value that sets in advance, adopt following formula that described initial codebook set is revised:

K=0,1,2 ... N _t-1;

Wherein, V is original initial codebook set, and Φ is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas,

Be revised new code book set, correction matrix Φ is shown below:

$\mathrm{\Φ}=\left[\begin{array}{cccc}{e}^{\mathrm{j\π}\frac{1}{{N_t}^2}}& 0& \mathrm{\Λ}& 0\\ 0& e^{\mathrm{j\π}\frac{2}{{N_t}^2}}& \mathrm{\Λ}& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& 0\\ 0& 0& \mathrm{\Λ}& e^{\mathrm{j\π}\frac{n}{{N_t}^2}}\end{array}\right];$

Wherein, n is the order of channel, N _tBe number of transmit antennas.

A kind of code book generating apparatus comprises initial codebook set generation unit, estimation unit, comparing unit and amending unit, wherein,

Initial codebook set generation unit is used to obtain initial codebook set and feedback, and amending unit is exported in the initial codebook set that obtains;

Estimation unit is used to estimate channel performance information, and exports to comparing unit;

Comparing unit is used for according to from the channel performance information of estimation unit, and when estimating that difference between any two code streams that obtain does not satisfy default non-correction conditions, the correction result notice that sends to amending unit needs correction for showing; When the difference between any two code streams of estimating to obtain satisfied default non-correction conditions, the correction result notice that sends to amending unit did not need correction for showing;

Amending unit is used to receive the correction result notice from comparing unit, when the correction result notice when showing that needs are revised, revise gathering, and export revised code book and gather from the initial codebook of initial codebook set generation unit; When the correction result notice does not need to revise for showing, will gather the initial codebook set of generation unit as code book set output from initial codebook

The technical scheme that provides from the invention described above comprises and obtains initial codebook set and feedback that according to the channel performance information of estimating to obtain, decision is revised in real time to initial codebook as can be seen.From the adaptive codebook generation method that the present invention is based on the code book correction as seen, on the basis that does not change existing code book basis matrix, performance statistics characteristic according to system, generated one group of new code book correction matrix, and consider original initial codebook set is revised in conjunction with feedback overhead, adjusted the precision of code book in time according to the real-time change of channel, under the very little situation of feedback overhead increase, expanded the capacity of code book, improved the precision of code book, thereby under the situation of Limited Feedback, improved the performance of precoding more effectively.

Description of drawings

Fig. 1 is the flow chart of method for generating codebooks of the present invention;

Fig. 2 is the composition structural representation of code book generating apparatus of the present invention.

Embodiment

Fig. 1 is the flow chart of method for generating codebooks of the present invention, as shown in Figure 1, may further comprise the steps:

Step 100: obtain initial codebook set and feedback.

In this step, the Basic codebook that is proposed with present each big standard (as 3GPP LTE, IEEE802.16m etc.) is initial codebook matrix set.Roughly comprise:

At first, utilize existing singular value decomposition (SVD) technology to decompose to estimate the channel condition information obtain at receiving terminal, decomposition method as shown in Equation (1):

H＝U∑V ^H (1)

Wherein, U and V are orthogonal matrixes, and V is the initial codebook set, ∑=diag (λ ₁, λ ₂λ _n) be the diagonal matrix that constitutes by singular value.

Then, according to the antenna configurations that system supported and the number of code stream, the V matrix in the formula (1) is quantized back its call number of feedback, the selection of code book collection is a foundation with the code book set of existing document or standard, repeats no more here.

Step 101: according to the channel performance information of estimating to obtain, decision is revised in real time to initial codebook.

In this step, estimate that the channel performance obtain is serves as to upgrade granularity or the cycle is estimated the statistic property of system with the time in the concrete system, such as to Signal to Interference plus Noise Ratio (SINR, Signal-to-Interference-Pulse-Noise Ratio) statistic property is estimated, to signal to noise ratio (snr), the estimation of statistic properties such as BER etc.Wherein, can adopt existing algorithm, repeat no more here the estimation of statistic properties such as SNR, BER.The present invention also proposes a kind of statistic property to SINR and estimates.

The estimation of SINR is carried out at each code stream, at receiving terminal its SINR is estimated, because the precoding vector of each code stream is all different, therefore, can adopt formula (2) that the SINR of each code stream is calculated:

${\mathrm{SINR}}_i\left(n\right)=\frac{{\left|\right|H_i{V}_i\left(n\right)\left|\right|}^2}{{\mathrm{\σ}}_i^2+\underset{k=1,k\≠i}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_i{V}_k\left|\right|}^2+{\left|\right|H_i{V}_i(:)\left|\right|}^2}---\left(2\right)$

Wherein, SINR _i(n) SINR of n code stream of i user of expression, H _iWith

Be respectively i user's channel matrix and noise power, V _i(n) be precoding codebook vector, V at n code stream of user i _i(:) is the precoding codebook vector of user i except that n code stream.V _kBe the precoding codebook vector of interference user, K is the number of all interference users.

When the performance statistics result who is obtained by formula (2) estimation is undesirable, promptly adopt the SINR of formula (2) to user i _i(n) estimation result, the SINR value between any two code streams (as n and m) should satisfy the condition shown in the formula (3):

|SINR _i(n)-SINR _i(m)|≤ε (3)

Wherein, ε is a default smaller value, the energy difference between any two code streams that expression allows.

When the SINR value between any two code streams that estimation obtains did not satisfy formula (3), the present invention proposed to introduce the code book correction matrix basic codebook matrix (being the initial codebook set) is revised, and specific implementation can adopt following two kinds of methods.

Method one: adopt correction matrix to initial codebook set revise, modification method as shown in Equation (4):

$\tilde{V}={\mathrm{VP}}^k$ k＝0，1，2，…N _t-1 (4)

Wherein, V is original initial codebook set, and P is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas, Be revised new code book set.

The order of supposing channel matrix is n, and then correction matrix P can be the square formation of one n * n, as shown in Equation (5):

$P=\left[\begin{array}{ccccc}0& 0& \mathrm{\Λ}& 0& 1\\ 1& 0& \mathrm{\Λ}& 0& 0\\ 0& 1& 0& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 1& 0\end{array}\right]---\left(5\right)$

Be 0 when modifying factor k is initial, when the SINR that estimates for the first time was discontented with pedal system demand (promptly not satisfying formula (3)), k increased progressively 1, otherwise k continues to remain 0, and the rest may be inferred.As can be seen, whether at this moment, only needing 1 bit of increase to feed back the k value needs to increase progressively to get final product.Along with the judgement of phase weekly adds up or keeps, make all code streams on all available antennas, to be rotated and obtain best spatial sub-channel.The present invention is based on the method for designing of the codebook matrix correction of Signal to Interference plus Noise Ratio, under the situation that only increases the 1bit feedback overhead, guaranteed that code stream abundant search in spatial domain is fit to the transmission subchannel of self.

Method two: the SINR to each road carries out balance, makes the difference of the SINR between each code stream dwindle as far as possible, and the present invention carries out balanced simple thinking to different code streams, has realized the balance of the error rate between code stream by simple method.Concrete grammar is as follows:

For order is 2 situation, modification method as shown in Equation (6):

$\tilde{V}=V\left[\begin{array}{cc}\sin \left(\mathrm{\θ}\right)& 0\\ 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right]---\left(6\right)$

In the formula (6), θ is a selectable angle, and span is 0≤θ＜pi/2, determine according to the condition number of channel of H matrix, and conditional number is big more, and value approaches pi/2 more.V is original initial codebook set,

Be revised new code book set.

For order greater than 2 situation, modification method as shown in Equation (7):

$\tilde{V}=V\left[\begin{array}{ccccc}\sin \left(\mathrm{\θ}\right)& 0& \mathrm{\Λ}& 0& 0\\ 0& \sin \left(\mathrm{\θ}\right)+\mathrm{\Δ}& \mathrm{\Λ}& 0& 0\\ 0& 0& \mathrm{\Λ}& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right]---\left(7\right)$

Wherein, the increment factor Δ satisfies It is an adjustable factors.θ is a selectable angle, and span is 0≤θ＜pi/2, determine according to the condition number of channel of H matrix, and conditional number is big more, and value approaches pi/2 more.V is original initial codebook set,

Be revised new code book set.

From the adaptive codebook generation method that the present invention is based on the code book correction as seen, on the basis that does not change existing code book basis matrix, performance statistics characteristic according to system, generated one group of new code book correction matrix, and consider original initial codebook set is revised in conjunction with feedback overhead, adjusted the precision of code book in time according to the real-time change of channel, under the very little situation of feedback overhead increase, expanded the capacity of code book, improved the precision of code book, thereby under the situation of Limited Feedback, improved the performance of precoding more effectively.

In addition, when adopting SINR to estimate that convergence rate estimation complexity slow or SINR is big, can adopt prior art that every data flow SNR is estimated.

If the estimation in this step is the estimation at the SNR statistic property, so, after adopting prior art that every data flow SNR is estimated, the SNR between any two code streams (as n and m) should satisfy formula (8):

|SNR _i(n)-SNR _i(m)|≤ε′ (8)

Wherein ε ' is default smaller value, the energy difference between any two code streams that expression allows.When the SNR value between any two code streams that estimation obtains does not satisfy formula (8), still can adopt the described method of said method one and method two that initial codebook is gathered and revise.

If the estimation in this step is the estimation at the BER statistic property, so, can only obtain the situation of BER for single data stream or other, when the system BER that adopts existing method statistic to go out is higher than a certain threshold value that sets in advance, adopt following method that initial codebook set is revised, as formula (9):

$\tilde{V}={\mathrm{\Φ}}^{k}V$ k＝0，1，2，…N _t-1 (9)

Wherein, V is original initial codebook set, and Φ is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas.

Be revised new code book set, correction matrix Φ is shown in formula (10) formula:

$\mathrm{\Φ}=\left[\begin{array}{cccc}{e}^{\mathrm{j\π}\frac{1}{{N_t}^2}}& 0& \mathrm{\Λ}& 0\\ 0& e^{\mathrm{j\π}\frac{2}{{N_t}^2}}& \mathrm{\Λ}& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& 0\\ 0& 0& \mathrm{\Λ}& e^{\mathrm{j\π}\frac{n}{{N_t}^2}}\end{array}\right]---\left(10\right)$

Wherein, n is the order of channel, N _tBe number of transmit antennas.

At the inventive method, a kind of code book generating apparatus also is provided, comprise initial codebook set generation unit,, estimation unit, comparing unit and amending unit, wherein,

Initial codebook set generation unit is used to obtain initial codebook set and feedback, and amending unit is exported in the initial codebook set that obtains.

Estimation unit is used to estimate channel performance information, and exports to comparing unit.

Comparing unit is used for according to from the channel performance information of estimation unit, and when estimating that difference between any two code streams that obtain does not satisfy default non-correction conditions, the correction result notice that sends to amending unit needs correction for showing; When the difference between any two code streams of estimating to obtain satisfied default non-correction conditions, the correction result notice that sends to amending unit did not need correction for showing.

Amending unit is used to receive the correction result notice from comparing unit, when the correction result notice when showing that needs are revised, revise gathering, and export revised code book and gather from the initial codebook of initial codebook set generation unit; When the correction result notice does not need to revise for showing, will gather the initial codebook set of generation unit as code book set output from initial codebook.

The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. a method for generating codebooks is characterized in that, comprising:

Obtain initial codebook set and feedback;

According to the channel performance information of estimating to obtain, decision is revised in real time to initial codebook.

2. method for generating codebooks according to claim 1 is characterized in that, described channel performance is Signal to Interference plus Noise Ratio SINR; Described estimation channel performance information is:

At each code stream, its SINR is shown in the following formula:

${\mathrm{SINR}}_i\left(n\right)=\frac{{\left|\right|H_i{V}_i\left(n\right)\left|\right|}^2}{{\mathrm{\σ}}_i^2+\underset{k=1,k\≠i}{\overset{K}{\mathrm{\Σ}}}{\left|\right|H_i{V}_k\left|\right|}^2+{\left|\right|H_i{V}_i(:)\left|\right|}^2};$

Wherein, SINR _i(n) SINR of n code stream of i user of expression, H _iWith

Be respectively i user's channel matrix and noise power, V _i(n) be precoding codebook vector, V at n code stream of user i _i(:) is the precoding codebook vector of user i except that n code stream, V _kBe the precoding codebook vector of interference user, K is the number of all interference users.

3. method for generating codebooks according to claim 2 is characterized in that, described decision is modified in real time to initial codebook:

Described SINR value between any two code streams does not satisfy | SINR _i(n)-SINR _i(m)) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows adopts correction matrix P, according to following formula described initial codebook set is revised:

$\tilde{V}={\mathrm{VP}}^k$ k＝0，1，2，…N _t-1，

Wherein, V is original initial codebook set, and P is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas,

Be revised new code book set;

Correction matrix

The order of wherein supposing channel matrix is n.

4. method for generating codebooks according to claim 2 is characterized in that, described decision is modified in real time to initial codebook:

Described SINR value between any two code streams does not satisfy | SINR _i(n)-SINR _i(m) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows is carried out balance to the SINR on each road.

5. method for generating codebooks according to claim 4 is characterized in that, described SINR to each road carries out balance and comprises:

For order is 2 situation, and modification method is shown below:

$\tilde{V}=V\left[\begin{array}{cc}\sin \left(\mathrm{\θ}\right)& 0\\ 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$ Wherein θ is a selectable angle, and span is 0≤θ＜pi/2;

Greater than 2 situation, modification method is shown below for order:

$\tilde{V}=V\left[\begin{array}{ccccc}\sin \left(\mathrm{\θ}\right)& 0& \mathrm{\Λ}& 0& 0\\ 0& \sin \left(\mathrm{\θ}\right)+\mathrm{\Δ}& \mathrm{\Λ}& 0& 0\\ 0& 0& \mathrm{\Λ}& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$

Wherein, the increment factor Δ satisfies

Be an adjustable factors, θ is a selectable angle, and span is 0≤θ＜pi/2;

V is original initial codebook set,

Be revised new code book set.

6. method for generating codebooks according to claim 1 is characterized in that, described channel performance is a signal to noise ratio snr.

7. method for generating codebooks according to claim 6 is characterized in that, described decision is modified in real time to initial codebook:

Described SNR value between any two code streams does not satisfy | SNR _i(n)-SNR _i(m) | during≤ε ', wherein, ε ' is a default smaller value, and the energy difference between any two code streams that expression allows adopts correction matrix P, according to following formula described initial codebook set is revised:

$\tilde{V}={\mathrm{VP}}^k$ k＝0，1，2，…N _t-1，

Wherein, V is original initial codebook set, and P is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas,

Be revised new code book set;

Correction matrix

The order of wherein supposing channel matrix is n.

8. method for generating codebooks according to claim 6 is characterized in that, described decision is modified in real time to initial codebook:

Described SINR between any two code streams does not satisfy | SINR _i(n)-SINR _i(m) | during≤ε, wherein, ε is a default smaller value, and the energy difference between any two code streams that expression allows is carried out balance to the SINR on each road;

Described SINR to each road carries out balance and comprises:

For order is 2 situation, and modification method is shown below:

$\tilde{V}=V\left[\begin{array}{cc}\sin \left(\mathrm{\θ}\right)& 0\\ 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$ Wherein θ is a selectable angle, and span is 0≤θ＜pi/2;

Greater than 2 situation, modification method is shown below for order:

$\tilde{V}=V\left[\begin{array}{ccccc}\sin \left(\mathrm{\θ}\right)& 0& \mathrm{\Λ}& 0& 0\\ 0& \sin \left(\mathrm{\θ}\right)+\mathrm{\Δ}& \mathrm{\Λ}& 0& 0\\ 0& 0& \mathrm{\Λ}& 0& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}\\ 0& 0& \mathrm{\Λ}& 0& \frac{1}{\sin \left(\mathrm{\θ}\right)}\end{array}\right],$

Wherein, the increment factor Δ satisfies

Be an adjustable factors, θ is a selectable angle, and span is 0≤θ＜pi/2;

V is original initial codebook set,

Be revised new code book set.

9. method for generating codebooks according to claim 1 is characterized in that, described channel performance is an error rate BER;

Described decision is modified in real time to initial codebook:

When the described system BER that estimates is higher than the threshold value that sets in advance, adopt following formula that described initial codebook set is revised:

K=0,1,2 ... N _t-1;

Wherein, V is original initial codebook set, and Φ is a correction matrix, and k is a modifying factor, N _tBe number of transmit antennas,

Be revised new code book set, correction matrix Φ is shown below:

$\mathrm{\Φ}=\left[\begin{array}{cccc}{e}^{\mathrm{j\π}\frac{1}{{N_t}^2}}& 0& \mathrm{\Λ}& 0\\ 0& e^{\mathrm{j\π}\frac{2}{{N_t}^2}}& \mathrm{\Λ}& 0\\ \mathrm{\Λ}& \mathrm{\Λ}& \mathrm{\Λ}& 0\\ 0& 0& \mathrm{\Λ}& e^{\mathrm{j\π}\frac{n}{{N_t}^2}}\end{array}\right];$

Wherein, n is the order of channel, N _tBe number of transmit antennas.

10. a code book generating apparatus is characterized in that, comprises initial codebook set generation unit, estimation unit, comparing unit and amending unit, wherein,

Initial codebook set generation unit is used to obtain initial codebook set and feedback, and amending unit is exported in the initial codebook set that obtains;

Estimation unit is used to estimate channel performance information, and exports to comparing unit;

Comparing unit is used for according to from the channel performance information of estimation unit, and when estimating that difference between any two code streams that obtain does not satisfy default non-correction conditions, the correction result notice that sends to amending unit needs correction for showing; When the difference between any two code streams of estimating to obtain satisfied default non-correction conditions, the correction result notice that sends to amending unit did not need correction for showing;

Amending unit is used to receive the correction result notice from comparing unit, when the correction result notice when showing that needs are revised, revise gathering, and export revised code book and gather from the initial codebook of initial codebook set generation unit; When the correction result notice does not need to revise for showing, will gather the initial codebook set of generation unit as code book set output from initial codebook.

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