A kind of estimation of channel matrix information and the method and apparatus of feedbackTechnical field
The present invention relates to a kind of MIMO in the communications field, (Multiple-Input Multiple-Output, multi input are moreOutput) estimation of channel matrix, the estimation of more particularly to a kind of channel matrix information and the method and apparatus of feedback in system.
Background technology
MIMO is one of key technology of the third generation mobile communication system.Mimo system uses in transmitting terminal and receiving terminalMore antenna elements, with advanced antenna transmission and signal processing technology, using the multipath transmisstion of wireless channel, because snobbishLead, development space resource, establish spatial parallelism transmission channel, in the case where not increasing bandwidth and transmission power, exponentially carryThe quality and message transmission rate of high radio communication.
In mimo systems, they are write as matrix by every transmission antenna to there is a channel between every reception antennaForm, just it is channel matrix.Such as a NTxRoot transmission antenna, NRxThe mimo system of root reception antenna, its channel squareBattle array is a NRx×NTxComplex matrix H.Wherein, the element h in HI, jRepresent jth root transmission antenna to the i-th piece-root grafting sending and receiving dayChannel coefficients between line, i=1 ... NRx, j=1 ... NTx.Here transmission antenna can be located at different transmitting terminals, reception antennaDifferent receiving terminals can be located at.Different with receiving terminal number according to the transmitting terminal for forming MIMO, mimo system has different pointsClass, it is respectively：SU-MIMO (Single-User MIMO, Single User MIMO), it is by a transmitting terminal and a receiving terminal structureInto；Mu-MIMO (Mulitple-User MIMO, multiuser MIMO), it is made up of a transmitting terminal and multiple receiving terminals；COMP(Cooperative Multi-Point Transmission, coordinated multipoint transmission), it is by multiple transmitting terminals and one or moreIndividual receiving terminal is formed.
Channel matrix H carries out SVD decomposition, i.e. H=U Λ VH, wherein, U is NRx×NRxUnitary matrice, be H left unusual arrowMoment matrix, V are NTx×NTxUnitary matrice, be H right singular vector matrix, Λ NRx×NTxDiagonal matrix, on its diagonalElement be H singular value, the conjugate transposition of subscript H representing matrixs.In communication process, if transmitting terminal knows channel matrixRight singular vector matrix or its quantized value, it is possible to using it to send signal pre-process, signal beam is referred toTo " direction " received most beneficial for user, so as to reduce the interference between data flow, the received signal to noise ratio of user is improved.At present shouldIt is the feedback method based on code book with relatively more technologies.This method is quantified channel space right singular vector matrix, shapeInto a codebook set.User is selected corresponding to a code book most matched with current channel matrix according to channel matrix informationIndex, i.e. PMI (Precoding Matrix Index, pre-coding matrix index), and the PMI is fed back into transmitting terminal.SendAccording to the PMI of this feedback corresponding code book is found in codebook set signal is pre-processed in end.After finally pre-processingSignal be sent to receiving terminal.This pretreatment has bigger gain for SU-MIMO.But for MU-MIMO or COMPFor, pre-processed according only to code book corresponding to the PMI of each receiving terminal feedback to sending signal, gain and unobvious.ButIf receiving terminal is capable of the left singular vector matrix or its quantized value of feedback channel matrixes, and suitably utilizes this left unusual arrowMoment matrix, its performance will be lifted further.Such as can be according to the left singular vector matrix of channel, right singular vector matrix, strangeDifferent value reconstruct channel matrix is in itself, it is well known that transmitting terminal knows channel matrix, can greatly promote MU-MIMO or COMPPerformance.
However, prior art is all that the right singular vector matrix of channel matrix is estimated and fed back, lack to left strangeThe correlation technique that different vector matrix is quantified and fed back.
The content of the invention
It is an object of the invention to provide a kind of estimation of channel matrix information and the method and apparatus of feedback, for solvingThe problem of to the quantization of left singular vector matrix in channel matrix and feedback.
According to an aspect of the invention, there is provided a kind of method of the estimation and feedback of channel matrix information, including withLower step：
Receiving terminal is filtered processing to the channel matrix of estimation and obtains equivalent channel matrix；
Receiving terminal is selected with a left side for equivalent channel matrix very according to equivalent channel matrix from receiving terminal codebook matrix setThe codebook matrix that different vector matrix matches；
Receiving terminal obtains its corresponding codebook matrix according to codebook matrix and indexed, then codebook matrix index is sent to hairSending end.
Preferably, receiving terminal selects from receiving terminal codebook matrix set and equivalent channel matrix according to equivalent channel matrixThe codebook matrix that matches of left singular vector matrix, including：
Receiving terminal calculates the conjugate transposition premultiplication of each codebook matrix in codebook matrix set with equivalent channel matrixNorm, obtain norm set；
Receiving terminal finds the codebook matrix for the maximum norm to be formed in norm set in receiving terminal codebook matrix set.
Preferably, receiving terminal selects from receiving terminal codebook matrix set and equivalent channel matrix according to equivalent channel matrixThe codebook matrix that matches of left singular vector matrix, including：
Receiving terminal calculates the left singular vector square of each codebook matrix and equivalent channel matrix in codebook matrix setThe distance of battle array, obtains distance set；
Receiving terminal finds the codebook matrix for the minimum range to form distance set in receiving terminal codebook matrix set.
Preferably, before receiving terminal obtains equivalent channel matrix according to the channel matrix of estimation, in addition to：
Receiving terminal carries out channel estimation, the channel matrix estimated to channel matrix.
Preferably, its corresponding codebook matrix is obtained according to codebook matrix in receiving terminal to index, then codebook matrix ropeInitiation is delivered to after transmitting terminal, in addition to：
Transmitting terminal is inquired about and read from transmitting terminal codebook matrix set according to codebook matrix index and indexed with codebook matrixCorresponding codebook matrix；
Transmitting terminal pre-processes according to the codebook matrix read from transmitting terminal codebook matrix set to sending signal.
Preferably, the set of receiving terminal codebook matrix and transmitting terminal codebook matrix set are two identical codebook matrixSet, is indexed including codebook matrix corresponding to codebook matrix and each codebook matrix respectively.
According to another aspect of the present invention, there is provided a kind of estimation of channel matrix information and the device of feedback, including withLower step：
Equivalent channel matrix computing module, equivalent channel square is obtained for being filtered processing to the channel matrix of estimationBattle array；
Codebook matrix indexes computing module, for select according to equivalent channel matrix from receiving terminal codebook matrix set andCodebook matrix that the left singular vector matrix of equivalent channel matrix matches simultaneously obtains its corresponding codebook matrix index；
Codebook matrix indexes feedback module, for codebook matrix index to be sent to transmitting terminal.
Preferably, device also includes：
Channel estimation module, for carrying out channel estimation, the channel matrix estimated to channel matrix.
Preferably, codebook matrix index computing module, including：
Codebook matrix norm calculation submodule, for by calculating being total to for each codebook matrix in codebook matrix setYoke transposition premultiplication obtains norm set with the norm of equivalent channel matrix；
Codebook matrix search index submodule, for searching the maximum model formed in norm set in codebook matrix setSeveral codebook matrix is inquired about and reads codebook matrix index corresponding with the codebook matrix.
Preferably, codebook matrix index computing module, including：
Codebook matrix Vector operation submodule, for by calculate each codebook matrix in codebook matrix set with etc.The distance of the left singular vector matrix of channel matrix is imitated, obtains distance set；
Codebook matrix search index submodule, the minimum range of distance set is formed for being searched in codebook matrix setCodebook matrix and read corresponding with codebook matrix codebook matrix and index.
Compared with prior art, the beneficial effects of the present invention are：The present invention is by selecting and equivalent channel matrixThe codebook matrix that left singular vector matrix matches is realized to the quantization of left singular vector matrix and feedback in channel matrix.
Brief description of the drawings
Fig. 1 is estimation and the method flow schematic diagram of feedback of channel matrix information provided by the invention；
Fig. 2 is estimation and the device block diagram of feedback of channel matrix information provided by the invention.
Embodiment
Below in conjunction with accompanying drawing to a preferred embodiment of the present invention will be described in detail, it will be appreciated that described below is excellentSelect embodiment to be merely to illustrate and explain the present invention, be not intended to limit the present invention.
Fig. 1 shows the estimation of channel matrix information provided by the invention and the method flow signal of feedback, such as Fig. 1 institutesShow：
Step S101, receiving terminal are filtered processing to the channel matrix of estimation and obtain equivalent channel matrix.
Before this, receiving terminal carries out channel estimation, the channel matrix estimated to channel matrix.
Step S102, receiving terminal select and equivalent channel square according to equivalent channel matrix from receiving terminal codebook matrix setThe codebook matrix that the left singular vector matrix of battle array matches.
There are two methods when selecting suitable codebook matrix, first, receiving terminal calculates each in codebook matrix setThe conjugate transposition premultiplication of individual codebook matrix obtains norm set, in receiving terminal code book square with the norm of the equivalent channel matrixThe codebook matrix for the maximum norm to be formed in the norm set is found in battle array set；Second, receiving terminal calculates the code bookThe distance of the left singular vector matrix of each codebook matrix and equivalent channel matrix in set of matrices, obtains distance set,The codebook matrix for the minimum range to form distance set is found in receiving terminal codebook matrix set again.
Step S103, receiving terminal obtain its corresponding codebook matrix according to codebook matrix and indexed, then codebook matrix ropeTransmitting terminal is delivered in initiation.
After this, transmitting terminal according to codebook matrix index inquired about from transmitting terminal codebook matrix set and read with it is describedCodebook matrix corresponding to codebook matrix index, according to the codebook matrix read from transmitting terminal codebook matrix set to sending signalPre-processed.Wherein, the set of receiving terminal codebook matrix and transmitting terminal codebook matrix set are two identical code book squaresBattle array set, is indexed including codebook matrix corresponding to codebook matrix and each codebook matrix respectively.
Fig. 2 shows the estimation of channel matrix information provided by the invention and the device block diagram of feedback, as shown in Fig. 2 bagInclude channel estimation module, equivalent channel matrix computing module, codebook matrix index computing module and codebook matrix index feedback mouldBlock.
Wherein, channel estimation module is used for each OFDM (Orthogonal in physical resource unit where estimating receiving terminalFrequency Division Multiplexing, OFDM)/OFMDA (Orthogonal FrequencyDivision Multiple Access, orthogonal frequency-time multiple access) channel matrix on each subcarrier of symbol.
Equivalent channel matrix computing module obtains equivalent channel matrix for being filtered processing to the channel matrix of estimation；
Codebook matrix index computing module be used to select from receiving terminal codebook matrix set according to equivalent channel matrix andCodebook matrix that the left singular vector matrix of equivalent channel matrix matches simultaneously obtains its corresponding codebook matrix index.The mouldBlock includes codebook matrix norm calculation submodule, codebook matrix Vector operation submodule and codebook matrix search index submodule,Codebook matrix norm calculation submodule is used for left by the conjugate transposition for calculating each codebook matrix in codebook matrix setThe norm of equivalent channel matrix is multiplied by, obtains norm set, codebook matrix Vector operation submodule is used for by calculating code book squareThe distance of the left singular vector matrix of each codebook matrix and equivalent channel matrix in battle array set, obtains distance set, codeThis matrix index inquires about submodule according to using its different function of method of selection codebook matrix also different, according to code bookMatrix norm calculating sub module selects suitable codebook matrix, then codebook matrix search index submodule is used in codebook matrix collectionThe codebook matrix of the maximum norm formed in norm set is searched in conjunction and reads codebook matrix rope corresponding with the codebook matrixDraw, select suitable codebook matrix according to codebook matrix Vector operation submodule, then codebook matrix search index submodule is usedIn the codebook matrix that the minimum range formed in distance set is searched in codebook matrix set and read and the codebook matrix pairThe codebook matrix index answered.
Codebook matrix index feedback module is used to codebook matrix index send to transmitting terminal.
Below by several specific embodiments, the method for estimation and feedback to channel matrix information of the present invention is carried out in detailExplanation.
Embodiment one：
In the present embodiment, physical resource unit accounts for N in time domainSIndividual OFDM/OFDMA symbols, account for N on frequency domainCIndividual frequency domainSub-carrier number.1 transmitting terminal scheduled 1 receiving terminal in this physical resource unit.Wherein, receiving terminal has NRxPiece-root grafting receives dayLine, transmitting terminal have NTxIndividual transmission antenna.Receiving terminal estimates that a left side for transmitting terminal to the channel matrix of receiving terminal is strange by the following methodThe codebook matrix index that different vector matrix matches, and codebook matrix index is fed back into transmitting terminal.
(1) channel matrix where receiving terminal estimation on each each subcarrier of OFDM/OFDMA symbols of physical resource unitH (m, n), its element hI, j(m, n) represents jth root transmission antenna to the channel coefficients between piece-root grafting sending and receiving antenna, m=1 ...,NS, n=1 ..., NC, i=1 ..., NRx, j=1 ..., NTx。
(2) receiving terminal calculates equivalent channel matrix according to the channel matrix H (m, n) in physical resource unit, i.e.,
Wherein, HeffIt is equivalent channel matrix, H (m, n) and αM, nIt is on m-th of OFDM/OFDMA, n-th of carrier wave respectivelyChannel matrix and the channel matrix in equivalent channel matrix specific gravity factor, αM, n>=0,M=1 ...,NS, n=1 ..., NC, NSFor OFDM/OFDMA symbol numbers, NCFor subcarrier in frequency domain number.
(3) the number r for being more than the first threshold value according to singular value selects codebook set Cr, in codebook set CrMiddle search makesObtain f ((Cr(i))H×Heff) maximum codebook matrix, and index is assigned to PMI corresponding to a codebook matrix.
Wherein, CrRepresent the codebook set that order is r, CR, PMIRepresent the codebook set C that order is rrCode book number, Cr(i) tableShow i-th of codebook matrix, i=1 ..., CR, PMI.R is HeffMore than the singular value number of the first threshold value.F (A) representing matrixs A'sNorm.Here, norm is the Common Concepts in matrix theory, for example the Frobenius norms of matrix A are expressed asaI, j, i=1 ..., M, j=1 ..., N is M × N matrix A element.
(4) PMI is fed back into transmitting terminal.
Embodiment two：
In the present embodiment, physical resource unit accounts for N in time domainSIndividual OFDM/OFDMA symbols, account for N on frequency domainCIndividual frequency domainSub-carrier number.1 transmitting terminal scheduled 1 receiving terminal in this physical resource unit.Wherein, receiving terminal has NRxPiece-root grafting receives dayLine, transmitting terminal have NTxIndividual transmission antenna.Receiving terminal estimates that a left side for transmitting terminal to the channel matrix of receiving terminal is strange by the following methodThe codebook matrix index that different vector matrix matches, and codebook matrix index is fed back into transmitting terminal.
(1) channel matrix where receiving terminal estimation on each each subcarrier of OFDM/OFDMA symbols of physical resource unitH (m, n), its element hI, j(m, n) represents jth root transmission antenna to the channel coefficients between piece-root grafting sending and receiving antenna, m=1 ...,NS, n=1 ..., NC, i=1 ..., NRx, j=1 ..., NTx。
(2) receiving terminal calculates equivalent channel matrix according to the channel matrix H (m, n) in physical resource unit, i.e.,
Wherein, HeffIt is equivalent channel matrix, H (m, n) and αM, nIt is on m-th of OFDM/OFDMA, n-th of carrier wave respectivelyChannel matrix and the channel matrix in equivalent channel matrix specific gravity factor, αM, n>=0,M=1 ...,NS, n=1 ..., NC, NSFor OFDM/OFDMA symbol numbers, NCFor subcarrier in frequency domain number.
(3) the number r for being more than the first threshold value according to singular value selects codebook set Cr, in codebook set CrMiddle search makesObtain d (Cr(i), U) minimum codebook matrix, and index is assigned to PMI corresponding to a codebook matrix.
Wherein, CrRepresent the codebook set that order is r, CR, PMIRepresent the codebook set C that order is rrCode book number, Cr(i) tableShow i-th of code book, i=1 ..., CR, PMI.R is HeffMore than the singular value number of the first threshold value.D (A, B) representing matrix A, B'sDistance, d (A, B)=f (AAH-BBH).U represents equivalent channel matrix HeffLeft singular vector matrix.F (A) representing matrixs A modelNumber.
(4) PMI is fed back into transmitting terminal.
Embodiment three：
In the present embodiment, physical resource unit accounts for N in time domainSIndividual OFDM/OFDMA symbols, account for N on frequency domainCIndividual frequency domainSub-carrier number.1 transmitting terminal scheduled N number of receiving terminal, as Mu-MIMO in this physical resource unit.Wherein, Mei GejieReceiving end has NRxRoot reception antenna, transmitting terminal have NTxIndividual transmission antenna.For each receiving terminal l perform respectively embodiment one orStep (1), (2), (3) in embodiment two are to estimate the left singular vector square of the channel matrix of transmitting terminal to receiving terminal l in itselfThe index for the codebook matrix that battle array matches, and codebook matrix index is fed back into transmitting terminal.Here, l=1 ..., N.
Example IV：
In the present embodiment, physical resource unit accounts for N in time domainSIndividual OFDM/OFDMA symbols, account for N on frequency domainCIndividual frequency domainSub-carrier number.M transmitting terminal scheduled N number of receiving terminal, as COMP in this physical resource unit.Wherein, it is each to receiveThere is N at endRxRoot reception antenna, each transmitting terminal have NTxIndividual transmission antenna.Each receiving terminal l performs embodiment one or real respectivelyThe step (1) in example two, (2), (3) are applied to estimate the left singular vector square of the channel matrix of M transmitting terminal to receiving terminal l in itselfThe codebook matrix index that battle array matches, the channel matrix is a NRx×(MNTx) complex matrix, and codebook matrix is indexedFeed back to each transmitting terminal.Here, l=1 ..., N.
Embodiment five
In the present embodiment, physical resource unit accounts for N in time domainSIndividual OFDM/OFDMA symbols, account for N on frequency domainCIndividual frequency domainSub-carrier number.M transmitting terminal scheduled N number of receiving terminal, as COMP in this physical resource unit.Wherein, it is each to receiveThere is N at endRxRoot reception antenna, each transmitting terminal have NTxIndividual transmission antenna.For each receiving terminal l perform respectively embodiment one orStep (1), (2), (3) in person's embodiment two is with the left unusual of channel matrix of k-th of the transmitting terminal of estimation to receiving terminal l in itselfThe codebook matrix index that vector matrix matches, the channel matrix is a NRx×NTxThe complex matrix of dimension, and by codebook matrixIndex feeds back to corresponding transmitting terminal k.Here, l=1 ..., N, k=1 ..., M.
In summary, the present invention has following technique effect：Using methods and apparatus of the present invention, in OFDM/OFDMA systemsIn system, receiving terminal can effectively estimate the left singular vector matrix of channel matrix, and be fed back to transmitting terminal, so as to which system can be withSignal is processed to improve mimo system using the information structuring channel matrix such as left singular vector matrix, and using channel matrixTransmission rate.
Although the present invention is described in detail above, the invention is not restricted to this, those skilled in the art can be withVarious modifications are carried out according to the principle of the present invention.Therefore, all modifications made according to the principle of the invention, all should be understood to fall intoProtection scope of the present invention.