CN101588190A - Method and device for channel estimation, and corresponding base station system - Google Patents

Abstract

The invention discloses a channel estimation method, a channel estimation device and a base station system. The method comprises: A, performing preliminary channel estimation on each antenna of a communication system; B, performing shaped combination on the preliminary channel estimation results of the antenna; and C, transforming and decomposing the channel estimation results subjected to shaped combination so as to obtain the channel estimation results of each antenna. The channel estimation device comprises a preliminary channel estimation module, a shaped combination module and a shaped-combination-result transformation module which execute the steps of the method respectively. The base station system comprises the channel estimation device. Noise and interference can be suppressed better by utilizing the invention so as to provide more accurate channel estimation performance.

Description

Channel estimation methods and device and relevant base station system

Technical field

The present invention relates to mobile communication technology, especially design channel estimation methods and device and relevant base station system in the mobile communication system.

Background technology

At present in most communication systems, in order to improve transmission reliability, the channel impulse response that need obtain passing through in the signals transmission, i.e. channel estimating.For example, in Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system, in order to realize joint-detection, wave beam forming and some measuring processes, channel estimation process is essential.

Present channel estimation methods mainly comprises blind channel estimation method and sends the method that training sequence carries out channel estimating.Owing to adopt the amount of calculation of blind channel estimation method very big, and estimated result is often not accurate enough, therefore, in existing communication system, more employings send the method for training sequence (being generally pilot frequency sequence) and carry out channel estimating, and the pilot frequency sequence here often is known pseudo random sequence.Transmitting-receiving two-end need be arranged identical pilot frequency sequence, the pilot frequency sequence that transmitting terminal sends is received by receiving terminal by after the channel, receiving terminal is according to the known pilot sequence (pilot frequency sequence when promptly with transmitting terminal sending identical) of the pilot frequency sequence of receiving with the local terminal record, can try to achieve described pilot frequency sequence by deconvolution or related operation and arrive the channel impulse response that receiving terminal experienced, finish channel estimating.

Be example with the TD-SCDMA system below, above-mentioned channel estimation methods is elaborated.

The TD-SCDMA system mainly adopts the low-cost channel estimation methods that is applicable to S-CDMA (CDMA) system, has finished channel estimating on the Minimum Mean Square Error meaning with simple fast Fourier transform (FFT) computing.

In the TD-SCDMA system, selected the building method of following user's training sequence (Midamble) sign indicating number sequence for use, by formula promptly the basic Midamble sign indicating number of (1) definition:

m_data＝(m ₁，m ₂，...，m _KW，m ₁，m ₂，...，m _KW-1) ^T (1)

The schematic diagram that Fig. 1 chooses for multi-user Midamble in the TD-SCDMA system.Referring to Fig. 1, m_data is a basic training sequences, and each user k (k=1 ..., K-1, K) the Midamble sign indicating number of Fa Songing is shifted in m_data and chooses, and promptly all users' Midamble sign indicating number all is the cyclic shift version of the same length Midamble sign indicating number that is.Like this, can utilize fft algorithm to calculate antenna k _a, k _a=1...K _aOn channel impulse response:

${\underset{\‾}{\overset{^}{h}}}^{\left(k_a\right)}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left({\underset{\‾}{e}}_m^{\left(k_a\right)}\right)}{\mathrm{FFT}\left(m\right)}\right)---\left(2\right)$

Wherein,

Represent k _aWhat receive on the root antenna passes through training sequence after the channel, and m is the training sequence that is sent.

In this mode, for all users in this sub-district, all adopt identical basic training sequences, just different user uses through the training sequence after the different displacements, so does not have interference in this sub-district between each user.But then adopt different basic training sequences between the adjacent community user, though between the employed basic training sequences of different districts certain orthogonality is arranged, but often also incomplete quadrature, because after adopting identical networking, the training sequence that different districts sends is overlapping in time, thereby can interfere with each other.

Therefore, there is following defective in the existing channel method of estimation:

In the existing channel method of estimation, each antenna is fully independently estimated, there be not the inhibition of consideration to noise and interference yet, the particularly externally inhibition of sub-district co-channel interference, thereby the existing channel method of estimation is not having to have preferable performance under the lower condition of co-channel interference and noise, but have under the bigger situation of co-channel interference or noise ratio, more weak to antinoise and interference capability, particularly the process of formula (2) worsens effect in addition to noise, it is serious to cause channel estimation results to worsen, and finally causes the severe exacerbation of systematic function.

Summary of the invention

In view of this, technical problem to be solved by this invention is to provide a kind of channel estimation methods, suppressing noise and interference better, thereby provides channel estimating performance more accurately.

Another technical problem to be solved by this invention is to provide a kind of channel estimating apparatus, suppressing noise and interference better, thereby provides channel estimating performance more accurately.

A technical problem more to be solved by this invention is to provide a kind of base station system, can suppress noise and interference better when carrying out channel estimating, thereby channel estimating performance more accurately is provided.

In order to realize the foregoing invention purpose, main technical schemes of the present invention is:

A kind of channel estimation methods comprises:

A, each antenna of communication system is carried out channel estimating, obtain preliminary channel estimation results;

B, described preliminary channel estimation results is carried out figuration merge;

C, the channel estimation results that described process figuration is merged carry out the channel estimation results that the conversion decomposition obtains each antenna.

Preferably, step B specifically comprises:

B1, determine the figuration combined vector of community user according to described preliminary channel estimation results;

B2, the figuration combined vector that utilizes described community user carry out figuration to the preliminary channel estimation results of each antenna of community user and merge.

Preferably, among the step B1, determine that the detailed process of the figuration combined vector of community user comprises:

B11, determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12, the eigenvalue of maximum of determining described each space covariance matrix and characteristic vector thereof are with the figuration combined vector of this eigenvalue of maximum characteristic of correspondence vector as community user.

Preferably, among the step B1, determine that the detailed process of the figuration combined vector of community user comprises:

B11 ', determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12 ', according to the arrival bearing of described spatial covariance matrix estimation community user;

B13 ', determine the array response vector of antenna, with the figuration combined vector of described array response vector as this community user corresponding to the community user arrival bearing.

Preferably, described communication system is the system of little spacing antenna array; Among the step B1,, take weight coefficient in wave beam forming as described figuration combined vector for this community user.

Preferably, step C is specially: the conjugate transpose that utilizes described figuration combined vector carries out conversion to the figuration amalgamation result of step B and decomposes the channel estimation results that obtains each antenna.

Preferably, step B specifically comprises:

B1, determine each arrival bearing's figuration combined vector of community user according to described preliminary channel estimation results;

The figuration of b2, structure community user merges matrix;

B3, utilize the figuration of community user to merge matrix the preliminary channel estimation results of each antenna of this community user is carried out figuration to merge.

Preferably, among the step b1, the detailed process of each arrival bearing's figuration combined vector of described definite community user comprises:

B11, determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12, the characteristic value of determining described space covariance matrix and characteristic of correspondence vector thereof;

B13, select characteristic value, with selected characteristic value characteristic of correspondence vector each arrival bearing's figuration combined vector as community user greater than predetermined threshold value.

Preferably, among the step b1, the detailed process of each arrival bearing's figuration combined vector of described definite community user comprises:

B11 ', determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12 ', according to effective arrival bearing of spatial covariance matrix estimation community user;

B13 ', determine the array response vector of each effective arrival bearing's correspondence of community user, with described array response vector each arrival bearing's figuration combined vector as community user.

Preferably, step C is specially: utilize conjugate transpose that described figuration merges matrix that the figuration amalgamation result of step B is carried out conversion and decompose the channel estimation results that obtains each antenna.

Preferably, further comprise in the described steps A: described preliminary channel estimation results is carried out noise reduction process; In subsequent step, determine described figuration combined vector according to the preliminary channel estimation results after this noise reduction process.

Preferably, described communication system comprises one or more sub-districts, and described community user is this community user, perhaps is this community user and outer community user.

Preferably, further comprise behind the step C: the channel estimation results of each each antenna of community user after step C is handled is arranged, and obtains the channel estimation results of each each antenna of sub-district.

Preferably, further comprise behind the described step C: the channel estimation results that step C is obtained carries out noise reduction process.

A kind of channel estimating apparatus, this device comprises:

Preliminary channel estimation module is used for each antenna of communication system is carried out channel estimating, obtains preliminary channel estimation results;

Figuration merges module, is used for that described preliminary channel estimation results is carried out figuration and merges;

Figuration amalgamation result conversion module is used for that the described channel estimation results that merges through figuration is carried out conversion and decomposes the channel estimation results that obtains each antenna.

Preferably, described figuration merging module specifically comprises:

The first figuration combined vector determination module is used for determining according to described preliminary channel estimation results the figuration combined vector of community user;

First figuration merges processing module, and the figuration combined vector that is used to utilize described community user carries out figuration to the preliminary channel estimation results of each antenna of this community user and merges.

Preferably, described figuration merging module specifically comprises:

The second figuration combined vector determination module is used for determining according to described preliminary channel estimation results each arrival bearing's figuration combined vector of community user;

Merge the matrix construction module, be used for merging matrix according to the figuration that each arrival bearing's figuration combined vector of described community user is constructed at this community user;

Second figuration merges processing module, is used to utilize the figuration of community user to merge matrix and the preliminary channel estimation results of this each antenna of community user is carried out figuration merges.

Preferably, this device further comprises the first noise reduction process module between preliminary channel estimation module and figuration merging module, be used for described preliminary channel estimation results is carried out noise reduction process, the preliminary channel estimation results after the output noise reduction process merges module to figuration and is used for determining described figuration combined vector.

Preferably, this channel estimating apparatus further comprises the arrangement module, is used for the channel estimation results of each each antenna of user of each sub-district after the described figuration amalgamation result conversion module processing is arranged, and obtains the channel estimation results of each each antenna of sub-district.

Preferably, this channel estimating apparatus further comprises the second noise reduction process module, is used for the channel estimation results after the described figuration amalgamation result conversion module processing is carried out noise reduction process.

A kind of base station system has channel estimating apparatus, and this channel estimating apparatus comprises:

Preliminary channel estimation module is used for each antenna of communication system is carried out preliminary channel estimating;

Figuration merges module, is used for that described preliminary channel estimation results is carried out figuration and merges;

Figuration amalgamation result conversion module is used for that the described channel estimation results that merges through figuration is carried out conversion and decomposes the channel estimation results that obtains each antenna.

With respect to prior art, the present invention has following beneficial effect:

The present invention goes for being equipped with the communication system of smart antenna, each antenna to each each user of sub-district carries out preliminary channel estimating earlier, preliminary channel estimation results to each antenna carries out the figuration merging again, and the final channel estimation results that obtains each antenna is decomposed in the channel estimation results conversion after will merging again at last.In process of the present invention, each antenna is not independently to carry out channel estimating, but has passed through the figuration merging process of a plurality of antennas, thereby has played the effect of space filtering, thereby played noise reduction and suppressed interference effect, channel estimating performance more accurately is provided.

The present invention is when carrying out channel estimating, both can utilize the signal of this community user to carry out channel estimating, also can utilize the signal of this sub-district and outer community user to carry out channel estimating, so the present invention both goes for single-cell environment, gone for many cell environments again.Under single-cell environment, can effectively suppress noise and interference in the channel estimating.For the common frequency multi-cell environment, except carrying out the channel estimating of this sub-district, also carry out outer each user's of sub-district channel estimating, not only can effectively suppress noise and interference in the channel estimating, multi-cell channel estimated result comparatively accurately can also be provided, thereby can obviously improve systematic function, elevator system capacity and throughput.

In addition, the present invention realizes also also uncomplicated, and cost is low, has very high realization and is worth.

Description of drawings

The schematic diagram that Fig. 1 chooses for multi-user Midamble in the TD-SCDMA system;

Fig. 2 is the main flow chart of first embodiment of channel estimation methods of the present invention;

Fig. 3 is the beam pattern that in fact the figuration merging process of first embodiment forms;

Fig. 4 is the main flow chart of second embodiment of channel estimation methods of the present invention;

Fig. 5 is the beam pattern that in fact the figuration merging process of second embodiment forms;

Fig. 6 is the composition schematic diagram of a kind of embodiment of channel estimating apparatus of the present invention

Fig. 7 is the composition schematic diagram of the another kind of embodiment of channel estimating apparatus of the present invention.

Embodiment

Below by specific embodiments and the drawings the present invention is described in further details.

Basic thought of the present invention is to utilize many antennas to carry out combined channel to estimate that it mainly is applicable to the communication system with array antenna.

Fig. 2 is the main flow chart of first embodiment of channel estimation methods of the present invention.Referring to Fig. 2, this flow process comprises:

Step 201: the preliminary channel estimation results of determining each each user of antenna of each sub-district in the communication system.

This step is mainly calculated definite according to existing method, for example can carry out channel estimating or carry out blind Channel Estimation etc. by training sequence.

The channel estimation results of supposing current each each antenna of sub-district is as described in formula (3), (4), (5):

${\hat{h}}_{\left(u\right)}=\left[\begin{array}{c}{\hat{h}}_{\left(u\right)}^1\\ {\hat{h}}_{\left(u\right)}^2\\ .\\ .\\ .\\ {\hat{h}}_{\left(u\right)}^{K_a}\end{array}\right],u=1...U---\left(3\right)$

${\hat{h}}_{\left(u\right)}^{k_a}=[{\hat{h}}_{(1,u)}^{k_a},{\hat{h}}_{(2,u)}^{k_a},...,{\hat{h}}_{(K_u,u)}^{k_a}],,u=1...U,k_a=1...K_a---\left(4\right)$

${\hat{h}}_{(k_u,u)}^{k_a}=[{\hat{h}}_{(k_u,u)}^{(k_a,1)},{\hat{h}}_{(k_u,u)}^{(k_a,2)},...,{\hat{h}}_{(k_u,u)}^{(k_a,W)}],u=1...U,k_u=1...K_u---\left(5\right)$

Wherein, U represents total co-frequency neighbor cell number, k _a=1...K _aThe expression antenna, K _uThe total number of window of expression sub-district u=1...U, k _u=1...K _u, u=1...U is corresponding to each user of each sub-district, and W represents that each user's window is long, and it has identified certain multidiameter delay.Described

Be the channel estimation results of u sub-district,

Be u sub-district, k _aThe channel estimation results of individual antenna,

Be u sub-district, k _aIndividual antenna, k _uIndividual user's channel estimation results.

K for u sub-district _uThe preliminary channel estimating of each antenna of individual user can be expressed as:

${\hat{h}}_{(k_u,u)}=\left[\begin{array}{c}{\hat{h}}_{(k_u,u)}^1\\ {\hat{h}}_{(k_u,u)}^2\\ .\\ .\\ .\\ {\hat{h}}_{(k_u,u)}^{\mathrm{Ka}}\end{array}\right],u=1...U,k_u=1...K_u---\left(6\right)$

So, each antenna channel estimated result of u each user of sub-district can be shown not with following formula (7):

${\hat{h}}_{\left(u\right)}=[{\hat{h}}_{(1,u)},{\hat{h}}_{(2,u)},...,{\hat{h}}_{(K_u,u)}],u=1...U,k_u=1...K_u---\left(7\right)$

Step 202: the channel estimation results to step 201 carries out noise reduction process.

In this step, can adopt existing noise gate method to carry out noise reduction process, promptly utilize the noise power during each antenna channel estimated result calculating channel of each sub-district is estimated in the formula (4), and by the certain thresholding of noise setting, tap power in the channel estimating and this thresholding are compared, and what be lower than this thresholding then is judged as noise and zero setting.

Suppose that the channel estimation results of each current each each antenna of sub-district is after the noise reduction process:

$h_{\left(u\right)}=\left[\begin{array}{c}{h}_{\left(u\right)}^1\\ h_{\left(u\right)}^2\\ .\\ .\\ .\\ h_{\left(u\right)}^{K_a}\end{array}\right],u=1...U---\left(8\right)$

$h_{\left(u\right)}^{k_a}=[h_{(1,u)}^{k_a},h_{(2,u)}^{k_a},...,h_{(K_u,u)}^{k_a}],,u=1...U,k_a=1...K_a---\left(9\right)$

$h_{(k_u,u)}^{k_a}=[h_{(k_u,u)}^{(k_a,1)},h_{(k_u,u)}^{(k_a,2)},...,h_{(k_u,u)}^{(k_a,W)}],u=1...U,k_u=1...K_u---\left(10\right)$

Described h _(u)Be channel estimation results through u sub-district after the noise reduction process, Be u sub-district, the k after the process noise reduction process _aThe channel estimation results of individual antenna,

Be u sub-district, the k after the process noise reduction process _aIndividual antenna, k _uIndividual user's channel estimation results.

For u sub-district, the k after the noise reduction process _uThe channel estimating of individual each antenna of user can be written as:

$h_{(k_u,u)}=\left[\begin{array}{c}{h}_{(k_u,u)}^1\\ h_{(k_u,u)}^2\\ .\\ .\\ .\\ h_{(k_u,u)}^{\mathrm{Ka}}\end{array}\right],u=1...U,k_u=1...K_u---\left(11\right)$

The channel estimation results of u each antenna of sub-district can be represented with following formula (12) so:

$h_{\left(u\right)}=[h_{(1,u)},h_{(2,u)},...,h_{(K_u,u)}],u=1...U,k_u=1...K_u---\left(12\right)$

Consider that for computation complexity this step 202 also can be skipped, the preliminary channel estimation results that promptly directly adopts step 201 to obtain is input to and carries out the calculating of figuration combined vector in the step 203.

Step 203: determine figuration combined vector corresponding to each users of all cells according to the above-mentioned preliminary channel estimation results that obtains:

$w_{(k_u,u)}=[{\mathrm{<figure-callout\; id="1"\; label="w\; k\; u"\; filenames="A2008101119170020H1.png,A2008101119170021H1.png"\; state="\{\{state\}\}">w</figure-callout>}}_{k_u}^{{}_{}},{\mathrm{<figure-callout\; id="2"\; label="w\; k\; u"\; filenames="A2008101119170021H1.png"\; state="\{\{state\}\}">w</figure-callout>}}_{k_u}^{{}_{}},...,w_{k_u}^{K_a}],u=1...U,k_u=1...K_u---\left(13\right)$

Described

Expression user k _u=1...K _u, u=1...U (i.e. u sub-district k _uIndividual user) figuration combined vector.In this step, can utilize existing beamforming algorithm to determine the figuration combined vector of described each users of all cells, concrete method has eigen beam figuration method (EBB algorithm) and fixed beam figuration method.

Described EBB algorithm mainly comprises: at first determine user k _u=1...K _u, the space covariance matrix of u=1...U

According to formula: $R_{(k_u,u)}=h_{(k_u,u)}{h}_{(k_u,u)}^H,u=1...U,k_u=1...K_u$ Determine, wherein

Determine according to formula (11),

For

Conjugate transpose, subscript H represents conjugate transpose, if do not have step 202 noise reduction process directly according to formula (6)

And conjugation means is determined Then, find the solution

Eigenvalue of maximum and characteristic of correspondence vector thereof, with this eigenvalue of maximum characteristic of correspondence vector as user k _u=1...K _u, the figuration combined vector of u=1...U

Described fixed beam figuration method mainly comprises: determine user k _u=1...K _u, the space covariance matrix of u=1...U

Pass through then

Carry out arrival bearing user and estimate (DOA estimation), then by user k _u=1...K _u, arrival bearing's estimated result of u=1...U determines the array response vector of antenna corresponding to this arrival bearing, and this array response vector is asked as final

For the system that uses little spacing antenna array, tend to realize that for this community user DOA estimates and descending wave beam forming, thereby can directly take in the weight coefficient of wave beam forming figuration combined vector as this user for this community user

Step 204: the figuration combined vector that utilizes described each each user of sub-district carries out figuration to the preliminary channel estimation results of each antenna of respective cell user and merges.That is: at the user k in the formula (6) _u=1...K _u, the preliminary channel estimation results of each antenna of u=1...U utilizes this user's that step 203 obtains figuration combined vector to carry out figuration and merges, and concrete mode is as described in the formula (14):

${\tilde{h}}_{(k_u,u)}=w_{(k_u,u)}{\hat{h}}_{(k_u,u)},u=1...U,k_u=1...K_u---\left(14\right)$

By the above-mentioned figuration merging process of this step 204, the channel estimating of a plurality of antennas of the described community user of formula (6) is merged into one, thereby has realized the effect of space filtering, the effect of having played noise reduction and having suppressed to disturb.

Step 205: the channel estimation results of each community user after the figuration that obtains according to step 204 merges, carry out conversion again by following formula (15) and resolve into a plurality ofly, each antenna that obtains each community user falls channel estimation results after hot-tempered by the space.

${\stackrel{\&OverBar;}{h}}_{(k_u,u)}=w_{(k_u,u)}^H{\tilde{h}}_{(k_u,u)},u=1...U,k_u=1...K_u---\left(15\right)$

Step 206: to the channel estimation results behind the figuration combined transformation in the formula (15), arrange according to the described method of formula (7), obtain the channel estimation results of each each antenna of sub-district, subsequently it is carried out noise reduction process, the method of noise reduction process can adopt existing noise gate processing method, thereby obtains final channel estimation results.

Pass through said process, at first channel is carried out just estimating, subsequently at each user of each sub-district, utilize smart antenna that the channel estimating of this each antenna of community user is carried out figuration and merge, reach the effect of space filtering, thereby reduce noise and interference, Fig. 3 is the beam pattern that in fact the figuration merging process of this first embodiment forms, referring to Fig. 3, the figuration merging process has the effect of enhancing for the signal from main lobe direction, and does not have reinforced effects for the signal beyond the main lobe.

More than provided the embodiment that considers many cell conditions among first embodiment, i.e. U＞1, community user wherein comprises this community user and outer community user.For the situation of single sub-district, be total co-frequency cell number U=1, its specific implementation step is same as the previously described embodiments.

Above-mentioned first embodiment is applicable to the environment that angular spread is less usually, for the bigger environment of angular spread, signal often has a plurality of arrival bearings, need make above-mentioned first embodiment and optimize and revise this moment, see also following second embodiment, Fig. 4 is the main flow chart of second embodiment of channel estimation methods of the present invention, and referring to Fig. 4, this second embodiment makes amendment for above-mentioned steps 203,204,205:

Step 203 ': utilize the definite figuration combined vector of each cell channel estimated result corresponding to each arrival bearing of each users of all cells

$w_{(k_u,u)}^{\left(k_d^u\right)}=[{\mathrm{<figure-callout\; id="1"\; label="w\; k\; u"\; filenames="A2008101119170020H1.png,A2008101119170021H1.png"\; state="\{\{state\}\}">w</figure-callout>}}_{k_u}^{{}_{}},{\mathrm{<figure-callout\; id="2"\; label="w\; k\; u"\; filenames="A2008101119170021H1.png"\; state="\{\{state\}\}">w</figure-callout>}}_{k_u}^{{}_{}},...,w_{k_u}^{K_a}],u=1...U,k_u=1...K_u,k_d^u=1...K_d^{k_u}---\left(16\right)$

And according to described The figuration of constructing each community user merges matrix

$A_{(k_u,u)}={[w_{(k_u,u)}^{\left(1\right)T},w_{(k_u,u)}^{\left(2\right)T},...,w_{(k_u,u)}^{\left(K_d^{k_u}\right)T}]}^T,u=1...U,k_u=1...K_u---\left(17\right)$

Here $k_d^u=1...K_d^{k_u}$ The k that represents u sub-district _uIndividual user's k _d ^uIndividual arrival bearing, wherein k _u=1...K _u, u=1...U,

The k that represents u sub-district _uAll arrival bearings of individual user, wherein k _u=1...K _u, u=1...U, described subscript T represents matrix is carried out transposition.

Here user k _u=1...K _u, u=1...U i.e. the k of u sub-district _uIndividual user is corresponding to each arrival bearing's figuration combined vector

Can try to achieve according to the channel estimating that obtains previously.

The method for solving here mainly contains two kinds:

(1) method of characteristic:

Promptly at first try to achieve user k _u=1...K _u, the space covariance matrix of u=1...U

Method for solving to participate in above-mentioned first be embodiment, try to achieve then

All characteristic values

I=1...K _aAnd characteristic vector I=1...K _a, characteristic value here and characteristic vector are corresponding one by one; According to the smart antenna theory, the characteristic value here

I=1...K _aMiddle maximum some values are associated with several effective arrival bearings, several minimum values are associated with noise, thereby can preestablish a thresholding Γ, and judge and an arrival bearing greater than the characteristic value correspondence of this thresholding Γ, otherwise its correspondence noise; Selection is greater than the characteristic value of thresholding Γ, with selected characteristic value characteristic of correspondence vector as user k _u=1...K _u, each arrival bearing's figuration combined vector of u=1...U, promptly get: $V_{(k_u,u)}^{\left(i\right)}{|}_{{\mathrm{\&lambda;}}_{(k_u,u)}^{\left(i\right)}\&GreaterEqual;\mathrm{\&Gamma;},i=1...K_a}$ As the figuration combined vector.

In fact, the effective vectorial number when here is for the moment, is the figuration combined vector that the described eigen beam figuration of above-mentioned first embodiment method (EBB algorithm) is tried to achieve.

(2) arrival bearing (DOA) method:

This method generally also needs to try to achieve earlier user k _u=1...K _u, the space covariance matrix of u=1...U

Basis again

Estimating user k _u=1...K _u, effective arrival bearing of u=1...U:

$k_d^u=1...K_d^{k_u};$ And then determine the array response vector of each effective arrival bearing's correspondence, with described array response vector as figuration combined vector corresponding to each arrival bearing

Need estimating user k herein, _u=1...K _uA plurality of effective arrival bearing of u=1...U, the DOA method of estimation that needs high-resolution for the less environment of angular spread, the DOA method of estimation here can be existing any DOA method of estimation, as the Bartlett spectral method, the Capon least variance method, the MUSIC algorithm, ESPRIT algorithms etc., effectively the DOA number also can calculate as the AIC in the ESPRIT algorithm (Akaike ' s information criterion) criterion and MDL (Rissanen ' s minimum description length) criterion by existent method etc.Obviously, when effective arrival bearing's number is one, then deteriorate to the figuration vector that fixed beam figuration method (GOB algorithm) that above-mentioned first embodiment mentions obtains.

Step 204 ': utilize described each each user's of sub-district figuration to merge matrix and the preliminary channel estimation results to each antenna of this community user is carried out figuration merge.That is: at the user k in the formula (6) _u=1...K _u, the preliminary channel estimation results of each antenna of u=1...U utilizes the described figuration of formula (17) to merge matrix and carries out figuration and merge, specifically as described in the formula (18):

${\tilde{h}}_{(k_u,u)}=A_{(k_u,u)}{\hat{h}}_{(k_u,u)},u=1...U,k_u=1...K_u---\left(18\right)$

The process that above-mentioned figuration merges has just been finished a kind of effect of space filtering of multi-beam, thereby the effect of having played noise reduction and having suppressed to disturb.Fig. 5 is the beam pattern that in fact the figuration merging process of second embodiment forms.Referring to Fig. 5, be example with two wave beams, above-mentioned figuration merging process has been equivalent to utilize multi-beam figuration directional diagram as shown in Figure 5 to carry out space filtering.

Step 205 ': the channel result of each community user after merging according to the figuration of step 204 ' obtain, carry out conversion again by following formula (19) and resolve into a plurality ofly, obtain each antenna of each user by the channel estimation results after the noise reduction of space:

${\stackrel{\&OverBar;}{h}}_{(k_u,u)}=A_{(k_u,u)}^H{\tilde{h}}_{(k_u,u)},u=1...U,k_u=1...K_u---\left(19\right)$

Other steps of second embodiment are identical with above-mentioned first embodiment.

By method of the present invention, realize comparatively simply, and can effectively suppress noise and interference in the channel estimating, significantly promoted the accuracy of channel estimating.

Corresponding with said method, the invention also discloses a kind of channel estimating apparatus, be used to carry out said method.Fig. 6 is the composition schematic diagram of a kind of embodiment of channel estimating apparatus of the present invention.Referring to Fig. 6, this device comprises:

Preliminary channel estimation module 601 is used for each antenna of communication system is carried out preliminary channel estimating.

The first noise reduction process module 602 is used for described preliminary channel estimation results is carried out noise reduction process, and the preliminary channel estimation results after the output noise reduction process merges module to figuration and is used for determining described figuration combined vector.This first noise reduction process module 602 is optional module, also can omit.

Figuration merges module 603, is used for the preliminary channel estimation results of described each antenna is carried out the figuration merging; In embodiment as shown in Figure 6, this figuration merges module 603 and specifically comprises:

The first figuration combined vector determination module 631 is used for determining according to described preliminary channel estimation results the figuration combined vector of community user; First figuration merges processing module 632, and the figuration combined vector that is used to utilize described community user carries out figuration to the preliminary channel estimation results of each antenna of this community user and merges.

Figuration amalgamation result conversion module 604, be used for that the described channel estimation results that merges through figuration is carried out conversion and decompose the channel estimation results that obtains each antenna, at figuration amalgamation result shown in Figure 6, figuration amalgamation result conversion module 604 utilizes the conjugate transpose of described figuration combined vector to carry out the conversion decomposition.

This channel estimating apparatus can further include arranges module 605, is used for the channel estimation results of each each antenna of user of each sub-district after the described figuration amalgamation result conversion module processing is arranged, and obtains the channel estimation results of each each antenna of sub-district.

This channel estimating apparatus can further include the second noise reduction process module 606, is used for the output result of channel estimation results after the described figuration amalgamation result conversion module processing or arrangement module 605 is carried out noise reduction process.

Fig. 7 is for the composition schematic diagram of the another kind of embodiment of channel estimating apparatus of the present invention, and referring to Fig. 7, it is different with the embodiment of Fig. 6 with channel estimation module 604 that the figuration of this embodiment merges module 6031, and other module is identical with the embodiment of Fig. 6.The figuration of present embodiment merges module 603 and specifically comprises:

The second figuration combined vector determination module 711 is used for determining according to described preliminary channel estimation results each arrival bearing's figuration combined vector of community user.

Merge matrix construction module 712, be used for merging matrix according to the figuration that each arrival bearing's figuration combined vector of described community user is constructed at this community user.

Second figuration merges processing module 713, is used to utilize the figuration of community user to merge matrix and the preliminary channel estimation results of this each antenna of community user is carried out figuration merges.

At the embodiment of Fig. 7, the conjugate transpose that described figuration amalgamation result conversion module 604 utilizes described figuration to merge matrix carries out conversion and decomposes.

Channel estimation methods of the present invention can be carried out by base station system, therefore the invention also discloses a kind of base station system, this base station system comprises above-mentioned channel estimating apparatus, suppressing noise and interference better when carrying out channel estimating, thereby provides channel estimating performance more accurately.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with the people of this technology in the disclosed technical scope of the present invention; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.

Claims (21)

1, a kind of channel estimation methods is characterized in that, comprising:

A, each antenna of communication system is carried out channel estimating, obtain preliminary channel estimation results;

B, described preliminary channel estimation results is carried out figuration merge;

C, the channel estimation results that described process figuration is merged carry out the channel estimation results that the conversion decomposition obtains each antenna.

2, method according to claim 1 is characterized in that, step B specifically comprises:

B1, determine the figuration combined vector of community user according to described preliminary channel estimation results;

B2, the figuration combined vector that utilizes described community user carry out figuration to the preliminary channel estimation results of each antenna of community user and merge.

3, method according to claim 2 is characterized in that, among the step B1, determines that the detailed process of the figuration combined vector of community user comprises:

B11, determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12, the eigenvalue of maximum of determining described each space covariance matrix and characteristic vector thereof are with the figuration combined vector of this eigenvalue of maximum characteristic of correspondence vector as community user.

4, method according to claim 2 is characterized in that, among the step B1, determines that the detailed process of the figuration combined vector of community user comprises:

B11 ', determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12 ', according to the arrival bearing of described spatial covariance matrix estimation community user;

B13 ', determine the array response vector of antenna, with the figuration combined vector of described array response vector as this community user corresponding to the community user arrival bearing.

5, method according to claim 2 is characterized in that, described communication system is the system of little spacing antenna array; Among the step B1,, take weight coefficient in wave beam forming as described figuration combined vector for this community user.

6, method according to claim 2 is characterized in that, step C is specially: the conjugate transpose that utilizes described figuration combined vector carries out conversion to the figuration amalgamation result of step B and decomposes the channel estimation results that obtains each antenna.

7, method according to claim 1 is characterized in that, step B specifically comprises:

B1, determine each arrival bearing's figuration combined vector of community user according to described preliminary channel estimation results;

The figuration of b2, structure community user merges matrix;

B3, utilize the figuration of community user to merge matrix the preliminary channel estimation results of each antenna of this community user is carried out figuration to merge.

8, method according to claim 7 is characterized in that, among the step b1, the detailed process of each arrival bearing's figuration combined vector of described definite community user comprises:

B11, determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12, the characteristic value of determining described space covariance matrix and characteristic of correspondence vector thereof;

B13, select characteristic value, with selected characteristic value characteristic of correspondence vector each arrival bearing's figuration combined vector as community user greater than predetermined threshold value.

9, method according to claim 7 is characterized in that, among the step b1, the detailed process of each arrival bearing's figuration combined vector of described definite community user comprises:

B11 ', determine the space covariance matrix of this community user according to the preliminary channel estimation results of each antenna of community user;

B12 ', according to effective arrival bearing of spatial covariance matrix estimation community user;

B13 ', determine the array response vector of each effective arrival bearing's correspondence of community user, with described array response vector each arrival bearing's figuration combined vector as community user.

10, want 7 described methods according to right, it is characterized in that step C is specially: utilize conjugate transpose that described figuration merges matrix that the figuration amalgamation result of step B is carried out conversion and decompose the channel estimation results that obtains each antenna.

11, want 2 to 10 each described methods according to right, it is characterized in that, further comprise in the described steps A: described preliminary channel estimation results is carried out noise reduction process; In subsequent step, determine described figuration combined vector according to the preliminary channel estimation results after this noise reduction process.

12, according to each described method of claim 2 to 10, it is characterized in that described communication system comprises one or more sub-districts, described community user is this community user, perhaps is this community user and outer community user.

13, method according to claim 12 is characterized in that, further comprises behind the step C: the channel estimation results of each each antenna of community user after step C is handled is arranged, and obtains the channel estimation results of each each antenna of sub-district.

14, according to each described method of claim 1 to 10, it is characterized in that,

Further comprise behind the described step C: the channel estimation results that step C is obtained carries out noise reduction process.

15, a kind of channel estimating apparatus is characterized in that, this device comprises:

Preliminary channel estimation module is used for each antenna of communication system is carried out channel estimating, obtains preliminary channel estimation results;

Figuration merges module, is used for that described preliminary channel estimation results is carried out figuration and merges;

Figuration amalgamation result conversion module is used for that the described channel estimation results that merges through figuration is carried out conversion and decomposes the channel estimation results that obtains each antenna.

16, channel estimating apparatus according to claim 15 is characterized in that, described figuration merges module and specifically comprises:

The first figuration combined vector determination module is used for determining according to described preliminary channel estimation results the figuration combined vector of community user;

First figuration merges processing module, and the figuration combined vector that is used to utilize described community user carries out figuration to the preliminary channel estimation results of each antenna of this community user and merges.

17, device according to claim 15 is characterized in that, described figuration merges module and specifically comprises:

The second figuration combined vector determination module is used for determining according to described preliminary channel estimation results each arrival bearing's figuration combined vector of community user;

Merge the matrix construction module, be used for merging matrix according to the figuration that each arrival bearing's figuration combined vector of described community user is constructed at this community user;

Second figuration merges processing module, is used to utilize the figuration of community user to merge matrix and the preliminary channel estimation results of this each antenna of community user is carried out figuration merges.

18, according to claim 16 or 17 described channel estimating apparatus, it is characterized in that, this device further comprises the first noise reduction process module between preliminary channel estimation module and figuration merging module, be used for described preliminary channel estimation results is carried out noise reduction process, the preliminary channel estimation results after the output noise reduction process merges module to figuration and is used for determining described figuration combined vector.

19, according to each described channel estimating apparatus of claim 15 to 17, it is characterized in that, this channel estimating apparatus further comprises the arrangement module, be used for the channel estimation results of each each antenna of user of each sub-district after the described figuration amalgamation result conversion module processing is arranged, obtain the channel estimation results of each each antenna of sub-district.

20, according to each described channel estimating apparatus of claim 15 to 17, it is characterized in that, this channel estimating apparatus further comprises the second noise reduction process module, is used for the channel estimation results after the described figuration amalgamation result conversion module processing is carried out noise reduction process.

21, a kind of base station system is characterized in that, has channel estimating apparatus, and this channel estimating apparatus comprises:

Preliminary channel estimation module is used for each antenna of communication system is carried out preliminary channel estimating;

Figuration merges module, is used for that described preliminary channel estimation results is carried out figuration and merges;

Figuration amalgamation result conversion module is used for that the described channel estimation results that merges through figuration is carried out conversion and decomposes the channel estimation results that obtains each antenna.

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