CN102710390A - Method and device for precoding in multi-user MIMO (multiple input multiple output) system - Google Patents

Abstract

The invention discloses a method and a device for precoding in a multi-user MIMO (multiple input multiple output) system. The method includes receiving pilot signals of users; computing spatial correlation matrixes according to the received pilot signals, and computing guiding matrixes of expected users according to the received pilot signals and pilot signals transmitted by the users; and computing precoding matrixes of the expected users according to inverses of the spatial correlation matrixes and the guiding matrixes. The method and the device have the advantages that computational complexity of precoding can be effectively reduced, and precoding also can be effectively carried out under the condition of co-channel interference which stops acquisition of channel information.

Description

The method and apparatus of precoding in a kind of multi-user MIMO system

Technical field

The present invention relates to the communications field, the method and apparatus of precoding in particularly a kind of multi-user MIMO system.

Background technology

Development of wireless communication devices improves transmission rate and quality round how all the time in abominable channel circumstance and limited bandwidth.Verified, the effective way that on wireless channel, improves data transmission rate and quality is to adopt many inputs/many output (MIMO) technology, the technology of promptly carrying out message transmission at the transmitting terminal and/or the receiving terminal use aerial array of wireless communication system.The MIMO technology increases exponentially the capability of communication system and the availability of frequency spectrum under the situation that does not increase bandwidth, be one of key technology that extensively adopts in the new generation of wireless GSM.The MIMO technology has been used for mobile radio systems such as WiMax and 4G.

Along with going deep into of multi-antenna technology research, the MIMO technology from point-to-point Single User MIMO technological expansion to the multi-user MIMO system of point-to-multipoint.In multi-user MIMO system, a plurality of users take identical running time-frequency resource simultaneously and communicate.The spatial degrees of freedom separate users that the many antennas of multiuser MIMO techniques make use provide; Each user can take identical running time-frequency resource; The precoding technique that signal relies on transmitting terminal suppresses interference among multiple users, effectively improves the sub-district average throughput through the running time-frequency resource multiplex mode.When cell load is heavier, just can obtain significant multi-user diversity gain through simple multi-subscriber dispatching algorithm, be the effective means that obtains high power system capacity.

MU-MIMO (multi-user imports/many outputs more) precoding technique not only will obtain bigger precoding gain, also need effectively reduce the interference between the user.In the MU-MIMO system, common-channel interference comprises and matches user's common-channel interference and non-matching user's common-channel interference.Can reach the upper limit of mimo channel capacity based on the method for multi-user pre-coding of dirty paper code (DPC, Dirty Paper Coding), yet because the high complexity of Nonlinear Processing, the DPC coding is also impracticable.Existing linear predictive coding algorithm is different according to the processing to common-channel interference, can be divided into two types of interference inhibition and interference eliminated.Interference suppression algorithm allows a part to disturb to exist, as maximization receive Signal to Interference plus Noise Ratio, maximization receive letter leak make an uproar than algorithm (Max Signal to Leakage and Noise Ratio, MSLNR) etc.Interference suppression algorithm is taken all factors into consideration user's interference and noise, and robustness is stronger, but generally needs each user's pre-coding matrix combined optimization.Interference cancellation algorithm is all eliminated the common-channel interference between the user, and the advantage of this type algorithm is clear physics conception, applying flexible, and shortcoming is because the restriction of the kernel degree of freedom often has certain requirement to number of antennas.Most representative in the interference cancellation algorithm is block diagonalization (Block Diagonalization, BD) zero forcing algorithm.(maximization receives letter and leaks the ratio of making an uproar based on MSLNR; Max Signal to Leakage and Noise Ratio) the precoding flow process of the MU-MIMO system of algorithm is as shown in Figure 1; Precoding flow process based on the MU-MIMO system of BD (block diagonalization, Block Diagonalization) algorithm is as shown in Figure 2.

No matter also be based on the MU-MIMO precoding of BD based on the MU-MIMO precoding of MSLNR; All need obtain the channel estimating of matching user and non-matching user; Need the user of precoding to construct interference matrix to each then; Then this interference matrix is handled accordingly, suppressed or interference eliminated to reach to disturb.Generally, the processing to interference matrix has accounted for the very most of of whole algorithm amount of calculation.A plurality of users need carry out such processing, will increase the amount of calculation of precoding greatly.With frequently disturbing under the situation about existing, the channel response that estimates the user who needs precoding preferably is the thing of difficulty very, and the channel response that will estimate all same frequency interference users also is the thing of difficulty very.Obviously, exist the channel estimating of evaluated error can worsen the performance of precoding.

Summary of the invention

How the method and apparatus of precoding in the multi-user MIMO system provided by the invention effectively reduces the amount of calculation of precoding with solution, and under the situation that has the same frequency interference that can not obtain channel information, also can carry out the problem of efficient precoding.

The invention discloses the method for precoding in a kind of multi-user MIMO system, said method comprises:

Receive user's pilot signal;

According to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user;

According to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

Preferably, said pilot signal computer memory correlation matrix according to reception specifically comprises:

Conjugation computer memory correlation matrix according to the pilot signal of pilot signal that receives and reception;

Saidly specifically comprise according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user:

According to the guiding matrix of the pilot signal that receives with the pilot signal calculation expectation user of desired user transmission.

Preferably, said according to the pilot signal computer memory correlation matrix that receives, also comprise before the guiding matrix according to the pilot signal that receives and user's pilot transmitted calculated signals desired user:

According to coherence bandwidth and coherence time pilot signal is divided into the basic resource blocks collection, each basic resource blocks is extracted pilot signal;

The conjugation computer memory correlation matrix of said pilot signal according to pilot signal that receives and reception specifically comprises:

For each basic resource blocks, calculate the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal;

Said pilot signal according to pilot signal that receives and desired user transmission is calculated the guiding matrix and is specifically comprised:

For each basic resource blocks, the pilot signal of sending according to the pilot signal of said basic resource blocks and desired user is calculated the guiding matrix of desired user on the said basic resource blocks;

Said pre-coding matrix according to the contrary of spatial correlation matrix and guiding matrix computations desired user specifically comprises:

For each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks;

For each desired user, at the pre-coding matrix of the said desired user of the positional alignment of time-frequency domain, obtain the pre-coding matrix of said desired user in basic resource blocks according to basic resource blocks.

Preferably, the conjugation of said pilot signal and pilot signal according to the said basic resource blocks spatial correlation matrix that calculates said basic resource blocks specifically comprises:

By element in the spatial correlation matrix of following formula calculating basic resource blocks,

$r_{i,j}^{\mathrm{nRB}}=(P_{n_{\mathrm{RB}}}^{\left(i\right)}\×{\left(P_{n_{\mathrm{RB}}}^{\left(j\right)}\right)}^H)/N_{\mathrm{pilot}}$

Wherein, Be n _RBElement in the spatial correlation matrix of individual basic resource blocks is represented the n of i reception antenna port _RBThe pilot tone of individual basic resource blocks and the n of j reception antenna port _RBThe cross correlation of the pilot tone of individual basic resource blocks,

Be the n of i reception antenna port _RBThe pilot tone row vector of individual basic resource blocks,

Be the n of j reception antenna port _RBThe pilot tone row vector of individual basic resource blocks, N _PilotBe the dimension of pilot tone row vector, i=1 ..., M _R, j=1 ..., M _R, M _RBe the reception antenna number; n _RB=1 ..., N _RB, N _RBQuantity for basic resource blocks.

Preferably, said pilot signal and desired user according to the said basic resource blocks pilot signal of the sending guiding matrix that calculates said basic resource blocks specifically comprises:

By element in the guiding matrix of following formula calculating basic resource blocks,

$g_t^{n_{\mathrm{RB}},s}=(P_{n_{\mathrm{RB}}}^{\left(t\right)}\×{\left(d_s^{n_{\mathrm{RB}}}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBThe guiding matrix column vector of individual basic resource blocks

T element, represent the n of t reception antenna port _RBThe reception pilot tone of individual basic resource blocks and the n of s desired user _RBThe cross correlation of the pilot tone of the transmission of individual basic resource blocks,

Be the n of t reception antenna port _RBThe pilot tone row vector of individual basic resource blocks,

Be the n of the pilot tone of s desired user transmission _RBThe pilot tone row vector of individual basic resource blocks, s=1 ..., N _D, N _DBe the expectation number of users, t=1 ..., M _R, M _RBe the reception antenna number; M _PilotDimension for pilot tone row vector.

Preferably, the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of said spatial correlation matrix according to said basic resource blocks specifically comprises:

By the pre-coding matrix of following formula calculation expectation user in basic resource blocks

$W^{n_{\mathrm{RB}}}={\left({\left(R^{n_{\mathrm{RB}}}\right)}^{-1}{G}^{n_{\mathrm{RB}}}\right)}^{*}$

Wherein,

Dimension be M _R* N _D,

Be that k desired user is at n _RBThe pre-coding matrix of individual basic resource blocks,

Be n _RBThe spatial correlation matrix of individual basic resource blocks,

Be n _RBThe guiding matrix of individual basic resource blocks, N _DBe the expectation number of users.

Preferably, also comprise after said reception user's the pilot signal:

If the pilot signal that receives has comprised all channel informations with the frequency user, then do not process;

If do not obtain comprising all pilot signals with frequency user's channel information simultaneously, each that then will in correlation time, obtain comprises with the pilot signal stack of user's channel information frequently, obtains comprising all pilot signals with frequency user's channel information.

Preferably, saidly each basic resource blocks extracted pilot signal specifically comprise:

With the pilot tone of each reception antenna port of each basic resource blocks by first frequency after after time or elder generation's time the extracted in order of frequency form pilot tone row vector.

Preferably, calculate element in the last triangle of spatial correlation matrix of basic resource blocks by said formula, in the following triangle in element and the last triangle element conjugation symmetrical.

The invention also discloses the device of precoding in a kind of multi-user MIMO system, said device comprises:

The pilot signal module is used to receive user's pilot signal;

The parameter matrix computing module is used for according to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user;

The precoding computing module is used for according to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

Preferably, said parameter matrix computing module specifically is used for the conjugation computer memory correlation matrix according to the pilot signal of pilot signal that receives and reception according to the pilot signal computer memory correlation matrix that receives the time;

Said parameter matrix computing module specifically is used for the guiding matrix according to the pilot signal calculation expectation user of pilot signal that receives and desired user transmission according to the guiding matrix of the pilot signal that receives and user's pilot transmitted calculated signals desired user the time.

Preferably, said device also comprises:

Divide module, be used for pilot signal being divided into the basic resource blocks collection, each basic resource blocks is extracted pilot signal according to coherence bandwidth and coherence time;

Said parameter matrix computing module specifically comprises:

The spatial correlation matrix calculating sub module is used for for each basic resource blocks, calculates the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal;

Guiding matrix computations submodule is used for for each basic resource blocks, calculates the guiding matrix of desired user on the said basic resource blocks according to the pilot signal and the pilot signal of desired user transmission of said basic resource blocks;

Said precoding computing module specifically is used for for each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks; For each desired user, at the pre-coding matrix of the said desired user of the positional alignment of time-frequency domain, obtain the pre-coding matrix of said desired user in basic resource blocks according to basic resource blocks.

The beneficial effect of the embodiment of the invention is: through receiving user's pilot signal; According to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user; According to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.The present invention can reduce the pre-coding matrix amount of calculation, improves system speed, and under the situation that has the same frequency interference that can not obtain channel information, also can carry out efficient precoding;

Method according to basic resource blocks is calculated pre-coding matrix, between precoding gain and amount of calculation, obtains good trading off;

Only element in the last triangle of the spatial correlation matrix of basic resource blocks is calculated, further reduce amount of calculation;

Calculate pre-coding matrix and need not carry out any channel estimating, both saved amount of calculation, avoided the channel estimation error transmission again;

Only need carry out matrix inversion one time, need not carry out other complex calculations, such as SVD, characteristic value decomposition etc. have improved the speed of the calculating pre-coding matrix of system;

Because the present invention is suppressing under the situation about disturbing, the adaptive to greatest extent characteristic of channel is so can obtain higher figuration gain for system.

Description of drawings

Fig. 1 is the precoding flow process figure of the MU-MIMO system of MSLNR algorithm in the prior art;

Fig. 2 is the precoding flow process figure of the MU-MIMO system of BD algorithm in the prior art;

Fig. 3 is the flow chart of the method for precoding in the multi-user MIMO system of the present invention;

Fig. 4 is the flow chart of the embodiment of the method for precoding in the multi-user MIMO system of the present invention;

Fig. 5 is the structure chart of the device of precoding in the multi-user MIMO system of the present invention.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, will combine accompanying drawing that embodiment of the present invention is done to describe in detail further below.

For time division duplex (TDD) system,, therefore can utilize the reciprocity of up-downgoing channel to carry out precoding because uplink downlink takies identical frequency resource.Wherein, in order from channel reciprocity, to benefit, to require the moment that input channel is observed and use the time-delay of this channel information between constantly less than channel coherence time.System can obtain user's channel information through each user's of receiving pilot signal, such as in TD-LTE, just can utilize the reference pilot of demodulation and the channel information that detecting pilot frequency obtains the user, carries out precoding.

In the MU-MIMO system, the base station can be expressed as through transmitting of precoding

$X=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{W}_j{s}_j$

Wherein, W _jBe pre-coding matrix corresponding to j user; s _jBe j user's data, total M is individual with the frequency user, the transmission signal of definition desired user

The pre-coding matrix of desired user

Desired user j (desired user is the terminal, UE) receiving terminal, the signal that receives can be expressed as:

$y_j=H_j{W}_j{s}_j+H_j\underset{i=1i\≠j}{\overset{M}{\mathrm{\Σ}}}{W}_i{s}_i+n_j$

Wherein, H _jChannel response for desired user j.The 1st is the data that desired user j need receive, and the 2nd is the interference of other user data to this user, and the 3rd is that average is 0, and variance is σ ²Multiple Gaussian noise, the 2nd and the 3rd all can exert an influence to the reception of desired user.Wherein, desired user j is certain user among the pairing user.The reception signal of definition desired user is

In linear MMSE (Minimum Mean Square Error) merges, select pre-coding matrix W to make desired user receiving terminal signal Y that receives and the root-mean-square error of sending signal S minimum:

$W=\{\arg \underset{w}{\min }E{\{S-Y\}}^2{\}}^{*}$

Definition:

$T=\underset{j=1}{\overset{M}{\mathrm{\Σ}}}{H}_j{s}_j$

So, then have

$W={\left\{\arg \underset{w}{\min }E{\{S-Y\}}^2\right\}}^{*}$

$={\left\{\arg \underset{w}{\min }E{\{S-W^{H}T\}}^2\right\}}^{*}$

$={\left\{E{\left\{T{T}^H\right\}}^{-1}E\right\{{\mathrm{TS}}^H\left\}\right\}}^{*}$

$={\left\{{\left(R\right)}^{-1}G\right\}}^{*}$

Wherein, spatial correlation matrix R=E{TT ^H, desired user guiding matrix G=E{TS ^H, () ^*The expression conjugation.T is equivalent to the base station when primary signal not being done precoding, the signal that desired user is received.Because W is to the spatial correlation matrix gained of directly inverting, and claims that this method is DMI (Direct Matrix Inverse, direct matrix is contrary).

Based on above-mentioned basic theories, according to the reciprocity of channel, the method flow of precoding is as shown in Figure 3 in the multi-user MIMO system provided by the invention.

Step S100, reception user's pilot signal.

Step S200 is according to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user.

Step S300 is according to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

In one embodiment, saidly specifically comprise: according to the conjugation computer memory correlation matrix of the pilot signal of pilot signal that receives and reception according to the pilot signal computer memory correlation matrix that receives.

Saidly specifically comprise: according to the pilot signal calculation expectation user's of pilot signal that receives and desired user transmission guiding matrix according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user.

For example; Reciprocity according to channel; To carry out precoding to descending MU-MIMO; Then only need just can obtain the pre-coding matrix W of desired user according to the pilot signal estimation space correlation matrix R of the up channel information that comprises each same frequency user that receives and the guiding matrix G of desired user.Suppose that the base station receives that to comprise M be Z with the pilot signal of user's channel information frequently, N wherein _DIndividual user is the MU-MIMO user of pairing.Suppose M>=N _D, that is to say that the user who on same frequency, communicates by letter is more than or equal to the pairing user.

The computer memory correlation matrix is expressed as

${\stackrel{\mathrm{\Λ}}{R}}_{z,z}=\frac{1}{m_t}\underset{i=0}{\overset{m_t-1}{\mathrm{\Σ}}}Z\left[i\right]Z{\left[i\right]}^H$

Wherein, m _tBe the pilot signal quantity that samples that adds up.Because Z has comprised all same frequency users' channel information, so only need calculate a spatial correlation matrix for all users.Calculate N _DThe guiding matrix of individual desired user

Suppose

Expression desired user pilot transmitted signal,

$\stackrel{\mathrm{\Λ}}{G}=\frac{1}{m_t}\underset{i=0}{\overset{m_t-1}{\mathrm{\Σ}}}Z\left[i\right]S{\left[i\right]}^H$

Wherein, the spatial correlation matrix of

j desired user.

Calculate N _DThe pre-coding matrix of individual desired user

$\stackrel{\mathrm{\Λ}}{W}={\left({\left({\stackrel{\mathrm{\Λ}}{R}}_{z,z}\right)}^{-1}\stackrel{\mathrm{\Λ}}{G}\right)}^{*}$

Wherein,

is the pre-coding matrix of k desired user.() ^*The expression conjugation.

In another embodiment, carrying out basic resource blocks and divide, is unit with the basic resource blocks, calculates precoding.This execution mode is specific as follows said

Step S201, reception user's pilot signal.

Further, for obtaining all channel informations, after receiving pilot signal, handle as follows with the frequency user.

If the pilot signal that receives has comprised all channel informations with the frequency user, then do not process.

If do not obtain comprising all pilot signals with frequency user's channel information simultaneously, each that then will in correlation time, obtain comprises with the pilot signal stack of user's channel information frequently, obtains comprising all pilot signals with frequency user's channel information.

Step S202 is divided into the basic resource blocks collection according to coherence bandwidth and coherence time with pilot signal, and each basic resource blocks is extracted pilot signal.

One practical implementation of extracting the method for pilot signal be exemplified as pilot tone with each reception antenna port of each basic resource blocks by first frequency after after time or elder generation's time the extracted in order of frequency form pilot tone row vector.

Step S203 for each basic resource blocks, calculates the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal.

One practical implementation of computer memory correlation matrix is exemplified below said.

By element in the spatial correlation matrix of following formula calculating basic resource blocks,

$r_{i,j}^{\mathrm{nRB}}=(P_{n_{\mathrm{RB}}}^{\left(i\right)}\×{\left(P_{n_{\mathrm{RB}}}^{\left(j\right)}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBElement in the spatial correlation matrix of individual basic resource blocks is represented the n of i reception antenna port _RBThe pilot tone of individual basic resource blocks and the n of j reception antenna port _RBThe cross correlation of the pilot tone of individual basic resource blocks;

Be the n of i reception antenna port _RBThe pilot tone row vector of individual basic resource blocks;

Be the n of j reception antenna port _RBThe pilot tone row vector of individual basic resource blocks; N _PilotBe the dimension of pilot tone row vector, the pilot number that promptly in basic resource blocks, samples; I=1 ..., M _R, j=1 ..., M _R, M _RBe the reception antenna number.n _RB=1 ..., N _RB, N _RBQuantity for basic resource blocks.

Further, because the cross correlation of identical two reception antenna ports conjugation each other, so by element in the last triangle of the spatial correlation matrix of said formula calculating basic resource blocks.Element conjugation symmetry in element and the last triangle in the following triangle.Adopt this mode, further save amount of calculation.

Step S204, for each basic resource blocks, the pilot signal of sending according to the pilot signal of said basic resource blocks and desired user is calculated the guiding matrix of desired user on the said basic resource blocks.

One practical implementation of calculating the guiding matrix is exemplified below said.

By element in the guiding matrix of following formula calculating basic resource blocks,

$g_t^{n_{\mathrm{RB}},s}=(P_{n_{\mathrm{RB}}}^{\left(t\right)}\×{\left(d_s^{n_{\mathrm{RB}}}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBThe guiding matrix column vector of individual basic resource blocks

T element, represent the n of t reception antenna port _RBThe reception pilot tone of individual basic resource blocks and the n of s desired user _RBThe cross correlation of the pilot tone of the transmission of individual basic resource blocks,

Be the n of t reception antenna port _RBThe pilot tone row vector of individual basic resource blocks,

Be the n of the pilot tone of s desired user transmission _RBThe pilot tone row vector of individual basic resource blocks, s=1 ..., N _D, N _DBe the expectation number of users, t=1 ..., M _R, M _RBe the reception antenna number; N _PilotDimension for pilot tone row vector.

Step S205 is for each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks.

One practical implementation of calculating pre-coding matrix is exemplified below said.

By the pre-coding matrix of following formula calculation expectation user in basic resource blocks

$W^{n_{\mathrm{RB}}}={\left({\left(R^{n_{\mathrm{RB}}}\right)}^{-1}{G}^{n_{\mathrm{RB}}}\right)}^{*}$

Wherein,

Dimension be M _R* N _D,

Be that k desired user is at n _RBThe pre-coding matrix of individual basic resource blocks,

Be n _RBThe spatial correlation matrix of individual basic resource blocks,

Be n _RBThe guiding matrix of individual basic resource blocks, N _DBe the expectation number of users.

Step S206 for each desired user, at the pre-coding matrix of the said desired user of the positional alignment of time-frequency domain in basic resource blocks, obtains the pre-coding matrix of said desired user according to basic resource blocks.Pre-coding matrix comprises the precoding of desired user on the time-frequency domain of scheduling.

Specific embodiment of the present invention is as shown in Figure 4.

In the precoding flow process that comprises MU-MIMO of the present invention system, need not carry out channel estimating with user frequently to each.In the spatial correlation matrix that calculates, comprised the channel information of all homogenous frequency signals, like this for all pairing users, only need to calculate a spatial correlation matrix, matrix inversion subsequently also only needs to calculate once to different pairing users.Through the narration of front, also can draw, the method that we provide also can operate as normal under existing with situation about disturbing frequently.

Step S401, structure comprises the pilot signal with frequency user's channel information e ^(p)(p=1 ..., M _R), M _RBe the reception antenna number.

If the pilot signal that receives has comprised all channel informations with the frequency user, then directly with the pilot signal that receives.

If can not obtain simultaneously comprising with the pilot signal of user's channel information frequently, each that then will in correlation time, obtain comprises to stack up with the pilot signal of user's channel information frequently and obtains pilot signal e ^(p)

Step S402, the basic resource blocks of division precoding.

According to coherence bandwidth and coherence time pilot signal e ^(p)(p=1 ..., M _R) be divided into the basic resource blocks collection (resource block, RB)

(p=1 ..., M _R, n _RB=1 ..., N _RB).N _RBQuantity for basic resource blocks.

Element do

(p=1 ..., M _RL=1 ..., N _Symb), just 1

Comprise N _SymbIndividual sampled point.At N _SymbIn the individual sampled point, possibly have only pilot signal, also might also have data-signal except pilot signal.

Step S403 extracts the pilot tone in the basic resource blocks.

N with p reception antenna port _RBIndividual basic resource blocks

In pilot tone by first frequency after the extracted in order of time (perhaps elder generation time after frequency) come out to form a row vector

Dimension be 1 * N _Pilot, N _PilotBe the n of p reception antenna port _RBIndividual basic resource blocks

In pilot number.The pilot number N of each reception antenna port _PilotIdentical.For each one receiving antenna corresponding basic resource block

have carried out pilot extracting the pilot can get a row vector

Step S404 asks n _RBThe spatial correlation matrix of individual basic resource blocks

Dimension be M _R* M _R, its element does

(i=1 ..., M _R, j=1 ..., M _R) expression i reception antenna port n _RBThe pilot tone of individual basic resource blocks and the n of j reception antenna port _RBThe cross correlation of the pilot tone of individual basic resource blocks, just:

$r_{i,j}^{\mathrm{nRB}}=(P_{n_{\mathrm{RB}}}^{\left(i\right)}\×{\left(P_{n_{\mathrm{RB}}}^{\left(j\right)}\right)}^H)/N_{\mathrm{pilot}}$

Wherein, (.) ^HConjugate transpose is asked in expression.

Physical meaning according to can be known;

so only needs calculating

to go up the element of triangle, can further save amount of calculation like this.

Step S405 asks n _RBThe spatial correlation matrix of individual basic resource blocks

Inverse matrix

Step S406 asks n _RBThe guiding matrix of the desired user of individual basic resource blocks

Dimension be M _R* N _D,

Its column vector (s=1 ..., N _D) expression s desired user guiding vector,

Element

(t=1 ..., M _R) expression t reception antenna port n _RBThe cross correlation of the pilot tone of the reception pilot tone of individual basic resource blocks and s desired user transmission.Need carry out precoding to desired user.

Just:

$g_t^{n_{\mathrm{RB}},s}=(P_{n_{\mathrm{RB}}}^{\left(t\right)}\×{\left(d_s^{n_{\mathrm{RB}}}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be the n of the pilot tone of s desired user transmission _RBThe pilot tone row vector of individual basic resource blocks.

Step S407 asks N _DIndividual MU-MIMO user's pre-coding matrix

$W^{n_{\mathrm{RB}}}={\left({\left(R^{n_{\mathrm{RB}}}\right)}^{-1}{G}^{n_{\mathrm{RB}}}\right)}^{*}$

Wherein,

Dimension be M _R* N _D,

It is k MU-MIMO user's pre-coding matrix.So at n _RBThe pre-coding matrix of the signal that sends on the running time-frequency resource of individual basic resource blocks correspondence does

Step S408 according to the pre-coding matrix of desired user on the basic resource blocks, obtains the pre-coding matrix of desired user on the time-frequency domain that is scheduled.

The reception data of each basic resource blocks are carried out the processing of step S403 to step S408, obtain N at last _DPre-coding matrix W on all running time-frequency resources of road ¹...,

The pre-coding matrix of each basic resource blocks that obtains, get up in the positional alignment of time-frequency domain according to each basic resource blocks, just obtain the pre-coding matrix of said desired user on the time-frequency domain that is scheduled, obtain N altogether _DIndividual MU-MIMO user's precoding W ¹...,

The device of precoding is as shown in Figure 5 in a kind of multi-user MIMO system.

Said device comprises:

Pilot signal module 100 is used to receive user's pilot signal;

Parameter matrix computing module 200 is used for according to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user;

Precoding computing module 300 is used for according to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

Preferable, said parameter matrix computing module specifically is used for the conjugation computer memory correlation matrix according to the pilot signal of pilot signal that receives and reception according to the pilot signal computer memory correlation matrix that receives the time;

Said parameter matrix computing module specifically is used for the guiding matrix according to the pilot signal calculation expectation user of pilot signal that receives and desired user transmission according to the guiding matrix of the pilot signal that receives and user's pilot transmitted calculated signals desired user the time.

Preferable, said device also comprises:

Divide module, be used for pilot signal being divided into the basic resource blocks collection, each basic resource blocks is extracted pilot signal according to coherence bandwidth and coherence time;

Said parameter matrix computing module specifically comprises:

The spatial correlation matrix calculating sub module is used for for each basic resource blocks, calculates the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal;

Guiding matrix computations submodule is used for for each basic resource blocks, calculates the guiding matrix of desired user on the said basic resource blocks according to the pilot signal and the pilot signal of desired user transmission of said basic resource blocks;

Said precoding computing module specifically is used for for each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks; For each desired user, according to the position of basic resource blocks, arrange the pre-coding matrix of said desired user in basic resource blocks at time-frequency domain, obtain the pre-coding matrix of said desired user.

Comprise the precoding of desired user on the time-frequency domain of scheduling in the said pre-coding matrix.

Preferable, said spatial correlation matrix calculating sub module specifically is used for calculating by following formula the spatial correlation matrix element of basic resource blocks,

$r_{i,j}^{\mathrm{nRB}}=(P_{n_{\mathrm{RB}}}^{\left(i\right)}\×{\left(P_{n_{\mathrm{RB}}}^{\left(j\right)}\right)}^H)/N_{\mathrm{pilot}}$

Wherein, Be n _RBElement in the spatial correlation matrix of individual basic resource blocks is represented the n of i reception antenna port _RBThe pilot tone of individual basic resource blocks and the n of j reception antenna port _RBThe cross correlation of the pilot tone of individual basic resource blocks,

Be the n of i reception antenna port _RBThe pilot tone row vector of individual basic resource blocks,

Be the n of j reception antenna port _RBThe pilot tone row vector of individual basic resource blocks, N _PilotBe the dimension of pilot tone row vector, i=1 ..., M _R, j=1 ..., M _R, M _RBe the reception antenna port number; n _RB=1 ..., N _RB, N _RBQuantity for basic resource blocks.

Further, calculate element in the last triangle of spatial correlation matrix of basic resource blocks by said formula, in the following triangle in element and the last triangle element conjugation symmetrical.

Preferable, said guiding matrix computations submodule specifically is used for calculating by following formula the guiding matrix element of basic resource blocks,

$g_t^{n_{\mathrm{RB}},s}=(P_{n_{\mathrm{RB}}}^{\left(t\right)}\×{\left(d_s^{n_{\mathrm{RB}}}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBThe guiding matrix column vector of individual basic resource blocks

T element, represent the n of t reception antenna port _RBThe reception pilot tone of individual basic resource blocks and the n of s desired user _RBThe cross correlation of the pilot tone of the transmission of individual basic resource blocks,

Be the n of t reception antenna port _RBThe pilot tone row vector of individual basic resource blocks, Be the n of the pilot tone of s desired user transmission _RBThe pilot tone row vector of individual basic resource blocks, s=1 ..., N _D, N _DBe the expectation number of users, t=1 ..., M _R, M _RBe the reception antenna number; N _PilotDimension for pilot tone row vector.

Preferable, said precoding computing module specifically is used for the pre-coding matrix in basic resource blocks by following formula calculation expectation user,

$W^{n_{\mathrm{RB}}}={\left({\left(R^{n_{\mathrm{RB}}}\right)}^{-1}{G}^{n_{\mathrm{RB}}}\right)}^{*}$

Wherein,

Dimension be M _R* N _D,

Be that k desired user is at n _RBThe pre-coding matrix of individual basic resource blocks,

Be n _RBThe spatial correlation matrix of individual basic resource blocks,

Be n _RBThe guiding matrix of individual basic resource blocks, N _DBe the expectation number of users.

Preferable, if said pilot signal module also is used for receiving after the pilot signal that receives the user pilot signal has comprised all channel informations with the frequency user, do not process; If do not obtain comprising all pilot signals with frequency user's channel information simultaneously, each that then will in correlation time, obtain comprises with the pilot signal stack of user's channel information frequently, obtains comprising all pilot signals with frequency user's channel information.

Preferable, divide module when each basic resource blocks is extracted pilot signal, specifically be used for pilot tone with each reception antenna port of each basic resource blocks by first frequency after after time or elder generation's time the extracted in order of frequency form pilot tone row vector.

The above is merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.All any modifications of within spirit of the present invention and principle, being done, be equal to replacement, improvement etc., all be included in protection scope of the present invention.

Claims (12)

1. the method for precoding in the multi-user MIMO system is characterized in that said method comprises:

Receive user's pilot signal;

According to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user;

According to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

2. method according to claim 1 is characterized in that,

Said pilot signal computer memory correlation matrix according to reception specifically comprises:

Conjugation computer memory correlation matrix according to the pilot signal of pilot signal that receives and reception;

Saidly specifically comprise according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user:

According to the guiding matrix of the pilot signal that receives with the pilot signal calculation expectation user of desired user transmission.

3. method according to claim 2 is characterized in that,

Said according to the pilot signal computer memory correlation matrix that receives, also comprise before the guiding matrix according to the pilot signal that receives and user's pilot transmitted calculated signals desired user:

According to coherence bandwidth and coherence time pilot signal is divided into the basic resource blocks collection, each basic resource blocks is extracted pilot signal;

The conjugation computer memory correlation matrix of said pilot signal according to pilot signal that receives and reception specifically comprises:

For each basic resource blocks, calculate the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal;

Said pilot signal according to pilot signal that receives and desired user transmission is calculated the guiding matrix and is specifically comprised:

For each basic resource blocks, the pilot signal of sending according to the pilot signal of said basic resource blocks and desired user is calculated the guiding matrix of desired user on the said basic resource blocks;

Said pre-coding matrix according to the contrary of spatial correlation matrix and guiding matrix computations desired user specifically comprises:

For each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks;

For each desired user, at the pre-coding matrix of the said desired user of the positional alignment of time-frequency domain, obtain the pre-coding matrix of said desired user in basic resource blocks according to basic resource blocks.

4. method according to claim 3 is characterized in that,

The spatial correlation matrix that the conjugation of said pilot signal and pilot signal according to said basic resource blocks is calculated said basic resource blocks specifically comprises:

By element in the spatial correlation matrix of following formula calculating basic resource blocks,

$r_{i,j}^{\mathrm{nRB}}=(P_{n_{\mathrm{RB}}}^{\left(i\right)}\×{\left(P_{n_{\mathrm{RB}}}^{\left(j\right)}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBElement in the spatial correlation matrix of individual basic resource blocks is represented the n of i reception antenna port _RBThe pilot tone of individual basic resource blocks and the n of j reception antenna port _RBThe cross correlation of the pilot tone of individual basic resource blocks,

Be the n of i reception antenna port _RBThe pilot tone row vector of individual basic resource blocks,

Be the n of j reception antenna port _RBThe pilot tone row vector of individual basic resource blocks, N _PilotBe the dimension of pilot tone row vector, i=1 ..., M _R, j=1 ..., M _R, M _RBe the reception antenna number; n _RB=1 ..., N _RB, N _RBQuantity for basic resource blocks.

5. method according to claim 4 is characterized in that,

The guiding matrix that said pilot signal of sending according to the pilot signal and the desired user of said basic resource blocks is calculated said basic resource blocks specifically comprises:

By element in the guiding matrix of following formula calculating basic resource blocks,

$g_t^{n_{\mathrm{RB}},s}=(P_{n_{\mathrm{RB}}}^{\left(t\right)}\×{\left(d_s^{n_{\mathrm{RB}}}\right)}^H)/N_{\mathrm{pilot}}$

Wherein,

Be n _RBThe guiding matrix column vector of individual basic resource blocks

T element, represent the n of t reception antenna port _RBThe reception pilot tone of individual basic resource blocks and the n of s desired user _RBThe cross correlation of the pilot tone of the transmission of individual basic resource blocks,

Be the n of t reception antenna port _RBThe pilot tone row vector of individual basic resource blocks, Be the n of the pilot tone of s desired user transmission _RBThe pilot tone row vector of individual basic resource blocks, s=1 ..., N _D, N _DBe the expectation number of users, t=1 ..., M _R, M _RBe the reception antenna number; N _PilotDimension for pilot tone row vector.

6. method according to claim 5 is characterized in that,

The pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of said spatial correlation matrix according to said basic resource blocks specifically comprises:

By the pre-coding matrix of following formula calculation expectation user in basic resource blocks

$W^{n_{\mathrm{RB}}}={\left({\left(R^{n_{\mathrm{RB}}}\right)}^{-1}{G}^{n_{\mathrm{RB}}}\right)}^{*}$

Wherein,

Dimension be M _R* N _D,

Be that k desired user is at n _RBThe pre-coding matrix of individual basic resource blocks,

Be n _RBThe spatial correlation matrix of individual basic resource blocks,

Be n _RBThe guiding matrix of individual basic resource blocks, N _DBe the expectation number of users.

7. method according to claim 1 is characterized in that,

Also comprise after said reception user's the pilot signal:

If the pilot signal that receives has comprised all channel informations with the frequency user, then do not process;

If do not obtain comprising all pilot signals with frequency user's channel information simultaneously, each that then will in correlation time, obtain comprises with the pilot signal stack of user's channel information frequently, obtains comprising all pilot signals with frequency user's channel information.

8. method according to claim 3 is characterized in that,

Saidly each basic resource blocks extracted pilot signal specifically comprise:

With the pilot tone of each reception antenna port of each basic resource blocks by first frequency after after time or elder generation's time the extracted in order of frequency form pilot tone row vector.

9. method according to claim 4 is characterized in that,

Calculate element in the last triangle of spatial correlation matrix of basic resource blocks by said formula, in the following triangle in element and the last triangle element conjugation symmetrical.

10. the device of precoding in the multi-user MIMO system is characterized in that said device comprises:

The pilot signal module is used to receive user's pilot signal;

The parameter matrix computing module is used for according to the pilot signal computer memory correlation matrix that receives, according to the pilot signal that receives and the guiding matrix of user's pilot transmitted calculated signals desired user;

The precoding computing module is used for according to the pre-coding matrix of the contrary of spatial correlation matrix with guiding matrix computations desired user.

11. device according to claim 10 is characterized in that,

Said parameter matrix computing module specifically is used for the conjugation computer memory correlation matrix according to the pilot signal of pilot signal that receives and reception according to the pilot signal computer memory correlation matrix that receives the time;

Said parameter matrix computing module specifically is used for the guiding matrix according to the pilot signal calculation expectation user of pilot signal that receives and desired user transmission according to the guiding matrix of the pilot signal that receives and user's pilot transmitted calculated signals desired user the time.

12. device according to claim 11 is characterized in that,

Said device also comprises:

Divide module, be used for pilot signal being divided into the basic resource blocks collection, each basic resource blocks is extracted pilot signal according to coherence bandwidth and coherence time;

Said parameter matrix computing module specifically comprises:

The spatial correlation matrix calculating sub module is used for for each basic resource blocks, calculates the spatial correlation matrix of said basic resource blocks according to the conjugation of the pilot signal of said basic resource blocks and pilot signal;

Guiding matrix computations submodule is used for for each basic resource blocks, calculates the guiding matrix of desired user on the said basic resource blocks according to the pilot signal and the pilot signal of desired user transmission of said basic resource blocks;

Said precoding computing module specifically is used for for each basic resource blocks, according to the pre-coding matrix of the desired user of the said basic resource blocks of guiding matrix computations of the contrary and said basic resource blocks of the spatial correlation matrix of said basic resource blocks; For each desired user, at the pre-coding matrix of the said desired user of the positional alignment of time-frequency domain, obtain the pre-coding matrix of said desired user in basic resource blocks according to basic resource blocks.

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