CN102710390B - The method and apparatus of precoding in a kind of multi-user MIMO system - Google Patents

Abstract

The present invention discloses the method and apparatus of precoding in a kind of multi-user MIMO system, and described method comprises: the pilot signal receiving user; According to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched; According to the pre-coding matrix of the inverse of spatial correlation matrix with guiding matrix computations desired user.The present invention can effectively reduce the amount of calculation of precoding, and when existence can not obtain the co-channel interference of channel information, also can carry out efficient precoding.

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 particularly precoding in a kind of multi-user MIMO system.

Background technology

The development of wireless communication technology is all the time round how to improve transmission rate and quality in severe channel circumstance and limited bandwidth.Verified, the most effective way improving data transmission rate and quality over the wireless channel adopts multiple input/multiple output (MIMO) technology, namely uses aerial array to carry out the technology of information transmission at the transmitting terminal of wireless communication system and/or receiving terminal.MIMO technology without increase in bandwidth, increases exponentially capacity and the availability of frequency spectrum of communication system, is one of key technology extensively adopted in new generation of wireless mobile communication system.MIMO technology is in the mobile radio systems such as WiMax and 4G.

Along with going deep into of multi-antenna technology research, MIMO technology is from point-to-point Single User MIMO technological expansion to the multi-user MIMO system of point-to-multipoint.In multi-user MIMO system, multiple user takies identical running time-frequency resource simultaneously and communicates.The spatial degrees of freedom separate users that multiuser MIMO technology utilizes multiple antennas to provide, each user can take identical running time-frequency resource, signal relies on the interference between the precoding technique suppression multi-user of transmitting terminal, effectively improves community average throughput by running time-frequency resource multiplex mode.When cell load is heavier, just can obtain significant multi-user diversity gain by simple multi-subscriber dispatching algorithm, be the effective means obtaining high power system capacity.

MU-MIMO (multi-user's multiple input/multiple output) precoding technique not only will obtain larger pre-coding gain, also needs the interference effectively reduced between user.In MU-MIMO system, common-channel interference comprises the pairing common-channel interference of user and the common-channel interference of non-matching user.Method for multi-user pre-coding based on dirty paper code (DPC, Dirty Paper Coding) can reach the upper limit of mimo channel capacity, but due to the high complexity of Nonlinear Processing, DPC coding is also impracticable.Existing linear predictive coding algorithm, according to different to the process of common-channel interference, can be divided into AF panel and interference elimination two class.Interference suppression algorithm allows part interference existence, receiving Signal to Interference plus Noise Ratio, maximizing to receive and believing that leakage is made an uproar than algorithm (Max Signal to Leakage and Noise Ratio, MSLNR) etc. as maximized.Interference suppression algorithm considers interference and the noise of user, and robustness is comparatively strong, but the general pre-coding matrix combined optimization needing each user.Common-channel interference between user is all eliminated by interference cancellation algorithm, and the advantage of this kind of algorithm is clear physics conception, applying flexible, and shortcoming is the restriction due to the kernel degree of freedom, often has certain requirement to number of antennas.Most representative in interference cancellation algorithm is block diagonalization (BlockDiagonalization, BD) zero forcing algorithm.(maximize based on MSLNR and receive letter leakage and to make an uproar ratio, MaxSignal to Leakage and Noise Ratio) algorithm MU-MIMO system precoding flow process as shown in Figure 1, based on the MU-MIMO system of BD (block diagonalization, Block Diagonalization) algorithm precoding flow process as shown in Figure 2.

MU-MIMO precoding no matter based on MSLNR or the MU-MIMO precoding based on BD, all need the channel estimating obtaining pairing user and non-matching user, then the user of precoding is needed to construct interference matrix for each, then this interference matrix is processed accordingly, to reach AF panel or interference elimination.Under normal circumstances, the very most of of whole algorithm amount of calculation be account for the process of interference matrix.Multiple user needs to carry out such process, will increase the amount of calculation of precoding greatly.Deposit in case in co-channel interference, estimate preferably and need the channel response of the user of precoding to be very difficult thing, and the channel response that will estimate all co-channel interference users is also very difficult thing.Obviously, the channel estimating that there is evaluated error can worsen the performance of precoding.

Summary of the invention

The method and apparatus of precoding in multi-user MIMO system provided by the invention, to solve the amount of calculation how effectively reducing precoding, and when existence can not obtain the co-channel interference of 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, described method comprises:

Receive the pilot signal of user;

According to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched;

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

Preferably, the described pilot signal computer memory correlation matrix according to receiving specifically comprises:

According to the conjugation computer memory correlation matrix of pilot signal of the pilot signal received and reception;

The guiding matrix of the pilot signal calculation expectation user that the described pilot signal according to reception and user launch specifically comprises:

According to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and desired user send.

Preferably, described according to receive pilot signal computer memory correlation matrix, according to receive pilot signal and user launch pilot signal calculation expectation user guiding matrix before also comprise:

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

The described conjugation computer memory correlation matrix according to the pilot signal of reception and the pilot signal of reception specifically comprises:

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

The pilot signal that the described pilot signal according to reception and desired user send calculates guiding matrix and specifically comprises:

For each basic resource blocks, calculate the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission;

The described pre-coding matrix according to the inverse of spatial correlation matrix and guiding matrix computations desired user specifically comprises:

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

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

Preferably, the described spatial correlation matrix calculating described basic resource blocks according to the pilot signal of described basic resource blocks and the conjugation of pilot signal specifically comprises:

Be calculated as follows element in the spatial correlation matrix 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-th _rBelement in the spatial correlation matrix of individual basic resource blocks, represents n-th of i-th reception antenna port _rBn-th of the pilot tone of individual basic resource blocks and a jth reception antenna port _rBthe cross correlation of the pilot tone of individual basic resource blocks, be n-th of i-th reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, for n-th of a jth reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, N _pilotfor the dimension of pilot tone row vector, i=1 ..., M _r, j=1 ..., M _r, M _rfor reception antenna number; n _rB=1 ..., N _rB, N _rBfor the quantity of basic resource blocks.

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

Be calculated as follows element in the guiding matrix 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-th _rBthe guiding matrix column vector of individual basic resource blocks t element, represent n-th of t reception antenna port _rBthe reception pilot tone of individual basic resource blocks and n-th of s desired user _rBthe cross correlation of the pilot tone of the transmission of individual basic resource blocks, be n-th of t reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks, s=1 ..., N _d, N _dfor expecting number of users, t=1 ..., M _r, M _rfor reception antenna number; M _pilotfor the dimension of pilot tone row vector.

Preferably, the pre-coding matrix of the desired user against basic resource blocks described in the guiding matrix computations with described basic resource blocks of the described spatial correlation matrix according to described basic resource blocks specifically comprises:

Be calculated as follows the pre-coding matrix of desired 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, for a kth desired user is n-th _rBthe pre-coding matrix of individual basic resource blocks, be n-th _rBthe spatial correlation matrix of individual basic resource blocks, be n-th _rBthe guiding matrix of individual basic resource blocks, N _dfor expecting number of users.

Preferably, described reception user pilot signal after also comprise:

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

If do not obtain the pilot signal comprising all channel informations with frequency user simultaneously, then each obtaining within correlation time is comprised the pilot signal superposition with the channel information of frequency user, obtain the pilot signal comprising all channel informations with frequency user.

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

The pilot tone of each reception antenna port of each basic resource blocks is formed pilot tone row vector by the extracted in order of frequency after time after first frequency or first time.

Preferably, by element in the upper triangle of the spatial correlation matrix of described formulae discovery basic resource blocks, in lower triangle, in element and upper triangle, element conjugation is symmetrical.

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

Pilot signal module, for receiving the pilot signal of user;

Parameter matrix computing module, for according to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched;

Precoding computing module, for the pre-coding matrix according to the inverse of spatial correlation matrix and guiding matrix computations desired user.

Preferably, described parameter matrix computing module according to during the pilot signal computer memory correlation matrix received specifically for the conjugation computer memory correlation matrix of pilot signal according to the pilot signal received and reception;

The guiding matrix of pilot signal calculation expectation user of described parameter matrix computing module when the guiding matrix of pilot signal calculation expectation user launched according to the pilot signal received and user specifically for sending according to the pilot signal received and desired user.

Preferably, described device also comprises:

Dividing module, for pilot signal being divided into basic resource blocks collection according to coherence bandwidth and coherence time, pilot signal being extracted to each basic resource blocks;

Described parameter matrix computing module specifically comprises:

Spatial correlation matrix calculating sub module, for for each basic resource blocks, calculates the spatial correlation matrix of described basic resource blocks according to the pilot signal of described basic resource blocks and the conjugation of pilot signal;

Guiding matrix computations submodule, for for each basic resource blocks, calculates the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission;

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

The beneficial effect of the embodiment of the present invention is: by receiving the pilot signal of user; According to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched; According to the pre-coding matrix of the inverse of spatial correlation matrix with guiding matrix computations desired user.The present invention can reduce pre-coding matrix amount of calculation, improves system speed, and when existence can not obtain the co-channel interference of channel information, also can carry out efficient precoding;

Calculate pre-coding matrix according to the method for basic resource blocks, between pre-coding gain and amount of calculation, obtain good trading off;

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

Calculate pre-coding matrix not need to carry out any channel estimating, both saved amount of calculation, and turn avoid the error propagation of channel estimating;

Only need to carry out a matrix inversion, do not need to carry out other complex calculations, such as SVD, Eigenvalues Decomposition etc., improve the speed of the calculating pre-coding matrix of system;

Because the present invention is when suppressing interference, adapt channel characteristic to greatest extent, so can obtain higher figuration gain for system.

Accompanying drawing explanation

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

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

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

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

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

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

For time division duplex (TDD) system, because uplink downlink takies identical frequency resource, the reciprocity of up-downgoing channel therefore can be utilized to carry out precoding.Wherein, in order to benefit from channel reciprocity, require input channel is observed moment and being used the time delay between this channel information moment to be less than channel coherency time.System can obtain the channel information of user by the pilot signal of each user received, such as in TD-LTE, the reference pilot of demodulation and detecting pilot frequency just can be utilized to obtain the channel information of user, carry out precoding.

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

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

Wherein, W _jfor corresponding to the pre-coding matrix of a jth user; s _jfor the data of a jth user, total M same user frequently, the transmission signal of definition desired user the pre-coding matrix of desired user

At desired user j (desired user is terminal, UE) receiving terminal, the signal received 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 _jfor the channel response of desired user j.1st data being desired user j and needing to receive, the 2nd is the interference of other user data to this user, and the 3rd is average is 0, and variance is σ ²multiple Gaussian noise, the 2nd and the 3rd all can have an impact to the reception of desired user.Wherein, desired user j is certain user in pairing user.The Received signal strength of definition desired user is

In linear MMSE (Minimum Mean Square Error) merges, the signal Y selecting pre-coding matrix W that desired user receiving terminal is received is minimum with the root-mean-square error sending signal S:

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

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, () ^*represent conjugation.T-phase when not doing precoding to primary signal in base station, the signal that desired user receives.Because W directly to invert gained to spatial correlation matrix, this method is claimed to be DMI (Direct MatrixInverse, direct matrix is inverse).

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

Step S100, receives the pilot signal of user.

Step S200, according to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched.

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

In one embodiment, the described pilot signal computer memory correlation matrix according to receiving specifically comprises: according to the conjugation computer memory correlation matrix of pilot signal of the pilot signal received and reception.

The guiding matrix of the pilot signal calculation expectation user that the described pilot signal according to reception and user launch specifically comprises: according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and desired user send.

For example, according to the reciprocity of channel, precoding to be carried out to descending MU-MIMO, then only need according to uplink receiving to comprise each pilot signal estimation space correlation matrix R of channel information with the user frequently and guiding matrix G of desired user, just can obtain the pre-coding matrix W of desired user.Supposing that base station receives the pilot signal comprising M the same channel information of user is frequently Z, N wherein _dindividual user is the MU-MIMO user of pairing.Suppose M>=N _d, be that is more than or equal to pairing user the user of same communication over frequencies.

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 _tfor carrying out the pilot signal quantity sampled added up.Because Z contains the channel information of all same frequency users, so only need calculation spatial correlation matrix for all users.Calculate N _dthe guiding matrix of individual desired user suppose represent the pilot signal that desired user is launched,

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

Wherein, the spatial correlation matrix of a jth 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, for the pre-coding matrix of a kth desired user.() ^*represent conjugation.

In another embodiment, carry out basic resource blocks division, in units of basic resource blocks, calculate precoding.Described in this execution mode is specific as follows

Step S201, receives the pilot signal of user.

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

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

If do not obtain the pilot signal comprising all channel informations with frequency user simultaneously, then each obtaining within correlation time is comprised the pilot signal superposition with the channel information of frequency user, obtain the pilot signal comprising all channel informations with frequency user.

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

The concrete implementation example of method extracting pilot signal be by the pilot tone of each reception antenna port of each basic resource blocks by the extracted in order of frequency after time after first frequency or elder generation's time to form pilot tone row vector.

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

One concrete implementation example of computer memory correlation matrix is as described below.

Be calculated as follows element in the spatial correlation matrix 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-th _rBelement in the spatial correlation matrix of individual basic resource blocks, represents n-th of i-th reception antenna port _rBn-th of the pilot tone of individual basic resource blocks and a jth reception antenna port _rBthe cross correlation of the pilot tone of individual basic resource blocks; be n-th of i-th reception antenna port _rBthe pilot tone row vector of individual basic resource blocks; for n-th of a jth reception antenna port _rBthe pilot tone row vector of individual basic resource blocks; N _pilotfor the dimension of pilot tone row vector, the pilot number namely sampled in basic resource blocks; I=1 ..., M _r, j=1 ..., M _r, M _rfor reception antenna number.N _rB=1 ..., N _rB, N _rBfor the quantity of basic resource blocks.

Further, due to the cross correlation conjugation each other of identical two reception antenna ports, therefore by element in the upper triangle of the spatial correlation matrix of described formulae discovery basic resource blocks.In lower triangle, in element and upper triangle, element conjugation is symmetrical.Adopt which, save amount of calculation further.

Step S204, for each basic resource blocks, calculates the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission.

The concrete implementation example calculating guiding matrix is as described below.

Be calculated as follows element in the guiding matrix 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-th _rBthe guiding matrix column vector of individual basic resource blocks t element, represent n-th of t reception antenna port _rBthe reception pilot tone of individual basic resource blocks and n-th of s desired user _rBthe cross correlation of the pilot tone of the transmission of individual basic resource blocks, be n-th of t reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks, s=1 ..., N _d, N _dfor expecting number of users, t=1 ..., M _r, M _rfor reception antenna number; N _pilotfor the dimension of pilot tone row vector.

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

The concrete implementation example calculating pre-coding matrix is as described below.

Be calculated as follows the pre-coding matrix of desired 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, for a kth desired user is n-th _rBthe pre-coding matrix of individual basic resource blocks, be n-th _rBthe spatial correlation matrix of individual basic resource blocks, be n-th _rBthe guiding matrix of individual basic resource blocks, N _dfor expecting number of users.

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

Specific embodiments of the invention as shown in Figure 4.

In the precoding flow process comprising MU-MIMO system of the present invention, do not need to carry out channel estimating to each with frequency user.In the spatial correlation matrix calculated, contain the channel information of all homogenous frequency signals, like this for all pairing users, only need calculating spatial correlation matrix, matrix inversion subsequently also only needs to calculate once to different pairing users.By describing above, also can draw, the method that we provide, when there is co-channel interference, also can normally work.

Step S401, structure comprises the pilot signal of the channel information with frequency user e ^(p)(p=1 ..., M _r), M _rfor reception antenna number.

If the pilot signal received has contained all channel informations with frequency user, then the direct pilot signal with receiving.

Comprise the pilot signal of the channel information with frequency user if can not obtain simultaneously, then the pilot signal each obtaining within correlation time being comprised the channel information of same frequency user stacks up and obtains pilot signal e ^(p).

Step S402, divides the basic resource blocks of precoding.

According to coherence bandwidth and coherence time pilot signal e ^(p)(p=1 ..., M _r) be divided into basic resource blocks collection (resource block, RB) (p=1 ..., M _r, n _rB=1 ..., N _rB).N _rBfor the quantity of basic resource blocks. element be (p=1 ..., M _r; L=1 ..., N _symb), namely 1 comprise N _symbindividual sampled point.At N _symbin individual sampled point, pilot signal may be only had, also likely except pilot signal also has data-signal.

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

By n-th of p reception antenna port _rBindividual basic resource blocks in pilot tone out form a row vector by the extracted in order of time after first frequency (or first time after frequency) dimension be 1 × N _pilot, N _pilotbe n-th of p reception antenna port _rBindividual basic resource blocks in pilot number.The pilot number N of each reception antenna port _pilotidentical.To the corresponding basic resource blocks of each reception antenna all carry out pilot extraction and just can obtain pilot tone row vector

Step S404, asks n-th _rBthe spatial correlation matrix of individual basic resource blocks dimension be M _r× M _r, its element is (i=1 ..., M _r, j=1 ..., M _r) represent n-th of i-th reception antenna port _rBn-th of the pilot tone of individual basic resource blocks and a jth reception antenna port _rBthe cross correlation of the pilot tone of individual basic resource blocks, namely:

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

Wherein, (.) ^hrepresent and ask conjugate transpose.

According to physical meaning known, so only need to calculate the element of upper triangle, can save amount of calculation so further.

Step S405, asks n-th _rBthe spatial correlation matrix of individual basic resource blocks inverse matrix

Step S406, asks n-th _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) represent the guiding vector of s desired user, element (t=1 ..., M _r) represent n-th of t reception antenna port _rBthe cross correlation of the reception pilot tone of individual basic resource blocks and the pilot tone of s desired user transmission.Need to carry out precoding to desired user.

Namely:

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

Wherein, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks.

Step S407, asks N _dthe pre-coding matrix of individual MU-MIMO 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, for the pre-coding matrix of a kth MU-MIMO user.So n-th _rBthe pre-coding matrix of the signal that the running time-frequency resource that individual basic resource blocks is corresponding sends is

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

The reception data of each basic resource blocks are carried out to the process of step S403 to step S408, finally obtain N _dpre-coding matrix W on all running time-frequency resources in road ¹..., the pre-coding matrix of each basic resource blocks obtained, get up according to the positional alignment of each basic resource blocks at time-frequency domain, just obtain the pre-coding matrix of described desired user on the time-frequency domain be scheduled, obtain N altogether _dthe precoding W of individual MU-MIMO user ¹...,

In a kind of multi-user MIMO system, the device of precoding as shown in Figure 5.

Described device comprises:

Pilot signal module 100, for receiving the pilot signal of user;

Parameter matrix computing module 200, for according to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched;

Precoding computing module 300, for the pre-coding matrix according to the inverse of spatial correlation matrix and guiding matrix computations desired user.

Preferably, described parameter matrix computing module according to during the pilot signal computer memory correlation matrix received specifically for the conjugation computer memory correlation matrix of pilot signal according to the pilot signal received and reception;

The guiding matrix of pilot signal calculation expectation user of described parameter matrix computing module when the guiding matrix of pilot signal calculation expectation user launched according to the pilot signal received and user specifically for sending according to the pilot signal received and desired user.

Preferably, described device also comprises:

Dividing module, for pilot signal being divided into basic resource blocks collection according to coherence bandwidth and coherence time, pilot signal being extracted to each basic resource blocks;

Described parameter matrix computing module specifically comprises:

Spatial correlation matrix calculating sub module, for for each basic resource blocks, calculates the spatial correlation matrix of described basic resource blocks according to the pilot signal of described basic resource blocks and the conjugation of pilot signal;

Guiding matrix computations submodule, for for each basic resource blocks, calculates the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission;

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

Described pre-coding matrix comprises the precoding of desired user on the time-frequency domain of scheduling.

Preferably, described spatial correlation matrix calculating sub module specifically for be calculated as follows basic resource blocks spatial correlation matrix in element,

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

Wherein, be n-th _rBelement in the spatial correlation matrix of individual basic resource blocks, represents n-th of i-th reception antenna port _rBn-th of the pilot tone of individual basic resource blocks and a jth reception antenna port _rBthe cross correlation of the pilot tone of individual basic resource blocks, be n-th of i-th reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, for n-th of a jth reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, N _pilotfor the dimension of pilot tone row vector, i=1 ..., M _r, j=1 ..., M _r, M _rfor reception antenna port number; n _rB=1 ..., N _rB, N _rBfor the quantity of basic resource blocks.

Further, by element in the upper triangle of the spatial correlation matrix of described formulae discovery basic resource blocks, in lower triangle, in element and upper triangle, element conjugation is symmetrical.

Preferably, described guiding matrix computations submodule specifically for be calculated as follows basic resource blocks guiding matrix in element,

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

Wherein, be n-th _rBthe guiding matrix column vector of individual basic resource blocks t element, represent n-th of t reception antenna port _rBthe reception pilot tone of individual basic resource blocks and n-th of s desired user _rBthe cross correlation of the pilot tone of the transmission of individual basic resource blocks, be n-th of t reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks, s=1 ..., N _d, N _dfor expecting number of users, t=1 ..., M _r, M _rfor reception antenna number; N _pilotfor the dimension of pilot tone row vector.

Preferably, described precoding computing module specifically for being calculated as follows the pre-coding matrix of desired 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, for a kth desired user is n-th _rBthe pre-coding matrix of individual basic resource blocks, be n-th _rBthe spatial correlation matrix of individual basic resource blocks, be n-th _rBthe guiding matrix of individual basic resource blocks, N _dfor expecting number of users.

Preferably, if the pilot signal of described pilot signal module also for receiving after the pilot signal receiving user has comprised all channel informations with frequency user, do not processed; If do not obtain the pilot signal comprising all channel informations with frequency user simultaneously, then each obtaining within correlation time is comprised the pilot signal superposition with the channel information of frequency user, obtain the pilot signal comprising all channel informations with frequency user.

Preferably, divide module when extracting pilot signal to each basic resource blocks specifically for the pilot tone of each reception antenna port by each basic resource blocks by first frequency after after time or first time the extracted in order of frequency form pilot tone row vector.

The foregoing is only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention.All any amendments done within the spirit and principles in the present invention, equivalent replacement, improvement etc., be all included in protection scope of the present invention.

Claims (7)

1. a method for precoding in multi-user MIMO system, is characterized in that, described method comprises:

Receive the pilot signal of user;

According to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched;

According to the pre-coding matrix of the inverse of spatial correlation matrix with guiding matrix computations desired user;

Wherein, the described pilot signal computer memory correlation matrix according to receiving specifically comprises:

According to the conjugation computer memory correlation matrix of pilot signal of the pilot signal received and reception;

The guiding matrix of the pilot signal calculation expectation user that the described pilot signal according to reception and user launch specifically comprises:

According to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and desired user send;

Wherein, described according to receive pilot signal computer memory correlation matrix, according to receive pilot signal and user launch pilot signal calculation expectation user guiding matrix before also comprise:

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

The described conjugation computer memory correlation matrix according to the pilot signal of reception and the pilot signal of reception specifically comprises:

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

The pilot signal that the described pilot signal according to reception and desired user send calculates guiding matrix and specifically comprises:

For each basic resource blocks, calculate the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission;

The described pre-coding matrix according to the inverse of spatial correlation matrix and guiding matrix computations desired user specifically comprises:

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

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

The described spatial correlation matrix calculating described basic resource blocks according to the pilot signal of described basic resource blocks and the conjugation of pilot signal specifically comprises:

Be calculated as follows element in the spatial correlation matrix of basic resource blocks,

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

Wherein, be n-th _rBelement in the spatial correlation matrix of individual basic resource blocks, represents n-th of i-th reception antenna port _rBn-th of the pilot tone of individual basic resource blocks and a jth reception antenna port _rBthe cross correlation of the pilot tone of individual basic resource blocks, be n-th of i-th reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, for n-th of a jth reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, N _pilotfor the dimension of pilot tone row vector, i=1 ..., M _r, j=1 ..., M _r, M _rfor reception antenna number; n _rB=1 ..., N _rB, N _rBfor the quantity of basic resource blocks.

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

The guiding matrix that the pilot signal that the described pilot signal according to described basic resource blocks and desired user send calculates described basic resource blocks specifically comprises:

Be calculated as follows element in the guiding matrix 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-th _rBthe guiding matrix column vector of individual basic resource blocks t element, represent n-th of t reception antenna port _rBthe reception pilot tone of individual basic resource blocks and n-th of s desired user _rBthe cross correlation of the pilot tone of the transmission of individual basic resource blocks, be n-th of t reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks, s=1 ..., N _d, N _dfor expecting number of users, t=1 ..., M _r, M _rfor reception antenna number; N _pilotfor the dimension of pilot tone row vector.

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

Described in the guiding matrix computations of the inverse and described basic resource blocks of the described spatial correlation matrix according to described basic resource blocks, the pre-coding matrix of the desired user of basic resource blocks specifically comprises:

Be calculated as follows the pre-coding matrix of desired 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, $W^{n_{\mathrm{RB}}}=[W_1^{n_{\mathrm{RB}}},\·\·\·,W_k^{n_{\mathrm{RB}}}\·\·\·,W_{N_D}^{n_{\mathrm{RB}}}],$ for a kth desired user is n-th _rBthe pre-coding matrix of individual basic resource blocks, be n-th _rBthe spatial correlation matrix of individual basic resource blocks, be n-th _rBthe guiding matrix of individual basic resource blocks, N _dfor expecting number of users.

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

Also comprise after the pilot signal of described reception user:

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

If do not obtain the pilot signal comprising all channel informations with frequency user simultaneously, then each obtaining within correlation time is comprised the pilot signal superposition with the channel information of frequency user, obtain the pilot signal comprising all channel informations with frequency user.

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

Describedly pilot signal extracted to each basic resource blocks specifically comprise:

The pilot tone of each reception antenna port of each basic resource blocks is formed pilot tone row vector by the extracted in order of frequency after time after first frequency or first time.

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

By element in the upper triangle of the spatial correlation matrix of described formulae discovery basic resource blocks, in lower triangle, in element and upper triangle, element conjugation is symmetrical.

7. a device for precoding in multi-user MIMO system, is characterized in that, described device comprises:

Pilot signal module, for receiving the pilot signal of user;

Parameter matrix computing module, for according to the pilot signal computer memory correlation matrix received, according to the guiding matrix of the pilot signal calculation expectation user that the pilot signal received and user are launched;

Precoding computing module, for the pre-coding matrix according to the inverse of spatial correlation matrix and guiding matrix computations desired user;

Wherein, described parameter matrix computing module according to during the pilot signal computer memory correlation matrix received specifically for the conjugation computer memory correlation matrix of pilot signal according to the pilot signal received and reception;

The guiding matrix of pilot signal calculation expectation user of described parameter matrix computing module when the guiding matrix of pilot signal calculation expectation user launched according to the pilot signal received and user specifically for sending according to the pilot signal received and desired user;

Wherein, described device also comprises:

Dividing module, for pilot signal being divided into basic resource blocks collection according to coherence bandwidth and coherence time, pilot signal being extracted to each basic resource blocks;

Described parameter matrix computing module specifically comprises:

Spatial correlation matrix calculating sub module, for for each basic resource blocks, calculates the spatial correlation matrix of described basic resource blocks according to the pilot signal of described basic resource blocks and the conjugation of pilot signal;

Guiding matrix computations submodule, for for each basic resource blocks, calculates the guiding matrix of desired user in described basic resource blocks according to the pilot signal of described basic resource blocks and the pilot signal of desired user transmission;

Described precoding computing module specifically for for each basic resource blocks, the pre-coding matrix of the desired user of basic resource blocks according to the guiding matrix computations of the inverse and described basic resource blocks of the spatial correlation matrix of described basic resource blocks; For each desired user, at the pre-coding matrix of basic resource blocks, obtain the pre-coding matrix of described desired user according to basic resource blocks desired user described in the positional alignment of time-frequency domain;

Guiding matrix computations submodule, for be calculated as follows basic resource blocks guiding matrix in element,

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

Wherein, be n-th _rBthe guiding matrix column vector of individual basic resource blocks t element, represent n-th of t reception antenna port _rBthe reception pilot tone of individual basic resource blocks and n-th of s desired user _rBthe cross correlation of the pilot tone of the transmission of individual basic resource blocks, be n-th of t reception antenna port _rBthe pilot tone row vector of individual basic resource blocks, be n-th of the pilot tone that s desired user sends _rBthe pilot tone row vector of individual basic resource blocks, s=1 ..., N _d, N _dfor expecting number of users, t=1 ..., M _r, M _rfor reception antenna number; N _pilotfor the dimension of pilot tone row vector.