CN103259582A - Multiple-spot synergy precoded coder conveying method, terminal and base station - Google Patents

Abstract

The invention provides a precoded coder achieving method which includes the following steps. A terminal obtains channel matrices between the terminal and a service base station and between the terminal and all synergy base stations. Time delays of signals of the service base station and the synergy base stations to the terminal are obtained. According to all the channel matrices, corresponding precoded codons of each channel matrices and indexes of precoded code matrices corresponding to the precoded codons are obtained. Phase correction matrices among the service base station and all the synergy base stations are obtained. The time delays, the indexes of the precoded code matrices and the phase correction matrices are fed back to the service base station. The service base station sends the time delays, the indexes of the precoded code matrices and the phase correction matrices to the synergy base stations. The synergy base stations process and emit the signals to the terminal based on the time delays, the indexes of the precoded code matrices and the phase correction matrices. The invention further provides a base station and the terminal.

Description

A kind of multi-point cooperative transmission method for precoding, terminal and base station

Technical field

The present invention relates to wireless communication field, in particular to a kind of multi-point cooperative transmission (Co-ordinated Multi-Point Transmission, CoMP) method for precoding, terminal and base station.

Background technology

(Long Term Evolution-Advanced LTE-A) in the system, has proposed to adopt the CoMP technology to improve the performance of system at the 3Gpp Long Term Evolution.The multi-point cooperative transmission technology is the cooperation between a plurality of transmission points that separate on the geographical position.In general, a plurality of transmission points are base stations of different districts.Wherein, descending multi-point cooperative transmission technical scheme mainly is divided into two classes: combined dispatching and unite transmission (JointTransmission, JT).Combined dispatching is the coordination by the time between the residential quarter, frequency and space resources, and (User Equipment, UE) resource of distribution mutually orthogonal is avoided interference each other for different terminals.The interference of minizone is the principal element of restriction cell edge UE performance, so combined dispatching can reduce the interference of minizone, thereby improves the performance of cell edge UE.

Have only a residential quarter different to UE transmission data with combined dispatching, uniting transmission then has a plurality of residential quarters to send data to UE simultaneously, receives signal to strengthen UE.As shown in Figure 1, two residential quarters send data to a UE on identical resource, and UE receives the signal of a plurality of residential quarters simultaneously.On the one hand, stack can promote the signal quality that UE receives from the useful signal of a plurality of residential quarters, on the other hand, has reduced the interference that UE is subjected to, thereby improves systematic function.

In addition, in traditional descending mimo system, all transmitting antennas are on a transmitting site.And geographical going up under the antenna scene at interval among Fig. 1, eNB1 (macrocell, Macro Cell) and eNB2 (Microcell, Pico Cell) are user's service at identical running time-frequency resource simultaneously, transmitting antenna is that these antenna is in different positions with respect to UE at interval geographically.Antenna port in the same transmit position is correlated with, and can think has same large scale shadow fading.And the transmitting antenna port that is in diverse location is normally incoherent, this mainly is because these transmitting antenna ports distance apart is far away, and environment on every side is rich scattering, and the transmitting antenna port table that is in diverse location reveals different large scale shadow fadings.When these transmitting antennas that are in diverse location were united to UE transmission data, channel presented the character different with traditional mimo channel.This channel that embodies new property just needs some different designs and CSI (channel state information, channel condition information) feedback mechanism.

Therefore, be necessary to seek high accuracy, and succinct practical CoMP precoding feedback and implementation method.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of precoding implementation method, terminal and base station, overcomes the influence that brings with the different arrival time delays of the many antennas in same base station between different base station.

In order to address the above problem, the invention provides a kind of precoding implementation method, comprising:

Terminal is obtained the channel matrix between itself and serving BS, each cooperative base station;

The signal that described terminal is obtained described serving BS and each cooperative base station reaches the time delay of described terminal;

Described terminal is obtained each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

Described terminal is obtained the phasing matrix between described serving BS and each cooperative base station;

Described terminal is given described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

Further, said method also can have following characteristics, and described terminal is obtained corresponding pre-encoding codeword according to channel matrix and comprised:

Described terminal is with channel matrix H _iCarry out singular value decomposition,

Extract V _IiPreceding m _kRow obtain channel estimating code word matrix With in the predefine code book with described

The shortest code word of distance as described channel matrix H _iCorresponding pre-encoding codeword;

Wherein, described H _iBe the channel matrix between described terminal and the described serving BS, perhaps, be the channel matrix between described terminal and the described cooperative base station.

Further, said method also can have following characteristics, and the phasing matrix that described terminal is obtained between described serving BS and each cooperative base station comprises:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$

Wherein, H ₁Be the channel matrix between described terminal and the described serving BS, W ₁Be H ₁Corresponding pre-encoding codeword, H _jBe the channel matrix between terminal and the cooperative base station, W _jBe H _jCorresponding pre-encoding codeword, tr[] expression asks the mark computing, $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$ Represent that the Θ of corresponding mark maximum is as described serving BS and described cooperative base station H _jBetween the phasing matrix.

The present invention also provides a kind of precoding implementation method, comprising:

The cooperative base station of terminal is from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, and described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station;

Described cooperative base station is carried out following processing with the signal of described terminal of giving to be sent: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place makes it be equivalent to the time domain time-delay, use the pre-encoding codeword corresponding with described precoding index to carry out precoding, the signal after handling is emitted to described terminal.

Further, said method also can have following characteristics, and described use phasing matrix carries out phasing and comprises:

Wherein, s ₁Be the signal of giving described terminal to be sent, It is the phasing matrix between described serving BS and the described cooperative base station.

Further, said method also can have following characteristics, and the described phasing matrix of described use carries out phasing, and the pre-encoding codeword that carries out the rotation of frequency domain phase place and use described precoding index to obtain carries out precoding processing and comprises:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Wherein, s ₁Be the signal of giving described terminal to be sent,

Be the phasing matrix, W ₂It is the pre-encoding codeword of described pre-coding matrix index correspondence, q be sub-carrier indices or with the particular resource unit associated index, N represents counting of inverse-Fourier transform, and τ is the time delay between described serving BS and the described cooperative base station, uses to postpone to count expression.

The present invention also provides a kind of terminal, comprising:

Channel estimation module is for the channel matrix that obtains between described terminal and serving BS, each cooperative base station;

The time delay estimation module, the signal that is used for obtaining described serving BS and each cooperative base station arrives the time delay of described terminal;

The pre-encoding codeword constructing module is used for obtaining each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

The phasing matrix estimation module is used for obtaining the phasing matrix between described serving BS and each cooperative base station;

Feedback module is used for giving described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

Further, above-mentioned terminal also can have following characteristics, and described pre-encoding codeword constructing module obtains corresponding pre-encoding codeword according to channel matrix and comprises:

With channel matrix H _iCarry out singular value decomposition, Extract V _IiPreceding m _kRow obtain channel estimating code word matrix With in the predefine code book with described The shortest code word of distance as described channel matrix H _iCorresponding pre-encoding codeword;

Wherein, described H _iBe the channel matrix between described terminal and the described serving BS, perhaps, be the channel matrix between described terminal and the described cooperative base station.

Further, above-mentioned terminal also can have following characteristics, and the phasing matrix that described terminal is obtained between described serving BS and each cooperative base station comprises:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$

Wherein, H ₁Be the channel matrix between described terminal and the described serving BS, W ₁Be H ₁Corresponding pre-encoding codeword, H _jBe the channel matrix between terminal and the cooperative base station, W _jBe H _jCorresponding pre-encoding codeword, tr[] expression asks the mark computing, $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$ Represent that the Θ of corresponding mark maximum is as described serving BS and described cooperative base station H _jBetween the phasing matrix.

The present invention also provides a kind of base station, comprising:

The information interaction module, when being used in described base station the cooperative base station as terminal, from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station;

Phasing and coding module, be used for the signal of described terminal of giving to be sent is carried out following processing: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place makes it be equivalent to the time domain time-delay, output signal to described precoding module;

Precoding module is used for using the pre-encoding codeword corresponding with described precoding index to carry out being emitted to described terminal after the precoding processing to the signal of described phasing and precoding module output.

Further, above-mentioned base station also can have following characteristics, and described phasing and coding module use phasing matrix carry out phasing and comprise:

Wherein, s ₁Be the signal of giving described terminal to be sent,

It is the phasing matrix between described serving BS and the described cooperative base station.

Further, above-mentioned base station also can have following characteristics, and described precoding module is used the pre-encoding codeword corresponding with described precoding index to carry out being emitted to described terminal after the precoding processing to the signal of phasing and precoding module output to comprise:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Wherein, s ₁Be the signal of giving described terminal to be sent,

Be the phasing matrix, W ₂It is the pre-encoding codeword of described pre-coding matrix index correspondence, q be sub-carrier indices or with the particular resource unit associated index, N represents counting of inverse-Fourier transform, τ is the time delay between described serving BS and the described cooperative base station, use and postpone to count expression, s _1CDDSignal for precoding module output.

The present invention is according to channel information, utilize cyclic delay diversity (Cyclic Delay Diversity, CDD) mode, to between different base station and the transmission time delay difference of same base station different antennae compensate, this method does not increase on the basis of user's receiving terminal complexity not changing the base station data transmitting time, adopt the precoding of layering phasing on the one hand, at base station different transmit antennas end signal is carried out cyclic shift to realize coherent transfer according to the delay inequality of terminal feedback on the other hand; The present invention compensates the transmission time delay difference of minizone, thereby has improved the robustness of CoMP system to the minizone delay inequality.And because the identical different channel of information via is merged at receiving terminal, the user has effectively utilized the diversity gain that channel provides, and has improved CoMP user and has received quality of signals.

Description of drawings

Fig. 1 is that the single user in two residential quarters who the present invention is based on the CoMP precoding of cyclic delay diversity uses schematic diagram;

Fig. 2 is that the embodiment of the invention is based on the flow chart of the CoMP precoding implementation method of cyclic delay diversity;

Fig. 3 is that the embodiment of the invention is based on the CoMP precoding realization design sketch of cyclic delay diversity;

Fig. 4 is embodiment of the invention terminal block diagram;

Fig. 5 is embodiment of the invention base station block diagram.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, hereinafter will carry out in detail+explanation embodiments of the invention by reference to the accompanying drawings.Need to prove that under the situation of not conflicting, the embodiment among the application and the feature among the embodiment be combination in any mutually.

The embodiment of the invention provides a kind of precoding implementation method, comprising:

Terminal is obtained the channel matrix between itself and serving BS, each cooperative base station;

The signal that described terminal is obtained described serving BS and each cooperative base station reaches the time delay of described terminal;

Described terminal is obtained each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

Described terminal is obtained the phasing matrix between described serving BS and each cooperative base station;

Described terminal is given described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

Wherein, described terminal according to a kind of method that channel matrix obtains corresponding pre-encoding codeword is:

Described terminal is with channel matrix H _iCarry out singular value decomposition,

Extract V _IiPreceding m _kRow obtain channel estimating code word matrix

With in the predefine code book with described

The shortest code word of distance as described channel matrix H _iCorresponding pre-encoding codeword;

Wherein, described H _iBe the channel matrix between described terminal and the described serving BS, perhaps, be the channel matrix between described terminal and the described cooperative base station.

Wherein, described terminal is obtained a kind of method of the phasing matrix between described serving BS and each cooperative base station and is:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$

Wherein, H ₁Be the channel matrix between described terminal and the described serving BS, W ₁Be H ₁Corresponding pre-encoding codeword, H _jBe the channel matrix between terminal and the cooperative base station, W _jBe H _jCorresponding pre-encoding codeword, tr[] expression asks the mark computing, $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$ Represent that the Θ of corresponding mark maximum is as described serving BS and described cooperative base station H _jBetween the phasing matrix.

The present invention also provides a kind of precoding implementation method, comprising:

The described serving BS of serving BS receiving terminal feedback and the phasing matrix between the time delay between each cooperative base station, serving BS and each cooperative base station, and, described terminal sends to corresponding cooperative base station corresponding to the pre-coding matrix index of each cooperative base station with described time delay, phasing matrix and pre-coding matrix index;

Cooperative base station is from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, and described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station;

Described cooperative base station is carried out following processing with the signal of described terminal of giving to be sent: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place makes it be equivalent to the time domain time-delay, use the pre-encoding codeword corresponding with described precoding index to carry out precoding, the signal after handling is emitted to described terminal.

Wherein, described use phasing matrix carries out phasing and comprises:

Wherein, s ₁Be the signal of giving described terminal to be sent,

It is the phasing matrix between described serving BS and the described cooperative base station.

Wherein, the described phasing matrix of described use carries out phasing, and the pre-encoding codeword that carries out the rotation of frequency domain phase place and use described precoding index to obtain carries out precoding processing and comprises:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Wherein, s ₁Be the signal of giving described terminal to be sent,

Be the phasing matrix, W ₂It is the pre-encoding codeword of described pre-coding matrix index correspondence, q be sub-carrier indices or with the particular resource unit associated index, N represents counting of inverse-Fourier transform, and τ is the time delay between described serving BS and the described cooperative base station, uses to postpone to count expression.

The embodiment of the invention provides a kind of CoMP precoding implementation method, comprising:

Suppose to have K eNB, a UE is only served in each residential quarter, and the UE of each residential quarter service uses same running time-frequency resource, and each eNB all has the M transmit antennas, and k user comprises N _kThe root reception antenna, user k need transmit m _kIndividual independent data stream.Certain eNB _k(k=1,2...K) signal of Fa Songing can be expressed as M dimensional vector W _ks _k, wherein, W _kM * m for user k _kThe dimension pre-coding matrix, and satisfy tr (W _kW _k ^H)=m _k, the computing of tr () expression mark, superscript H represents conjugate transpose computing, s _kBe the m of user k _kDimension emission symbolic vector.

Adopting the JT mode with two residential quarters is that user's service is example, and wherein eNB1 is serving BS, and eNB2 is cooperative base station, and user UE1 is desired user, and then the implementation procedure to the precoding of user UE1 is described below:

1) estimate channel, to serving BS eNB1, the channel matrix H 1 between user UE1 estimation and serving BS eNB1.To cooperative base station eNB2, the channel matrix H 2 between user UE1 estimation and cooperative base station eNB2.

2) time delay between the estimation different districts

The different channels state information references pilot tone that user UE1 comprises according to same position in the signal resource piece of two residential quarters transmission estimates Serving cell respectively and cooperation cell sends data to the moment that reaches the user, again both is subtracted each other the delay inequality τ that obtains two minizones.τ=t ₂-t ₁, t wherein ₁, t ₂Be respectively the moment of serving BS eNB1 and cooperative base station eNB2 signal transmitted arrival user UE1.UE1 is to serving BS eNB1 feedback delay τ.

3) structure pre-encoding codeword

In the UE1 side, choose code word, the code word w in the traversal code book from code book (as determining the LTE agreement) lining of precoding _i(wherein i is the code word sequence number in the corresponding code book) carries out singular value decomposition with channel matrix H 1, namely

Obtain channel estimating code word matrix:

$W_{H_1}=V_{11,\left[m_k\right]}$

Wherein

Be V ₁₁Preceding m _kRow, H1 is the N between UE1 and this cell base station eNB1 _k* M ties up channel matrix, U ₁₁Be N _k* M ties up unitary matrice, V ₁₁Be that M * M ties up unitary matrice, ε ₁₁=diag (σ ₁, σ ₂..., σ _r), r=rank (H ₁), diag represents diagonal matrix, the computing of rank () expression order, σ ₁, σ ₂..., σ _rIt is the singular value of channel matrix H 1.

Then travel through channel estimating code word matrix

With code word w in the code book _iDistance, the estimated value W that is the sub-pre-encoding codeword of expectation that distance is minimum ₁, a kind of method of calculating distance is:

$W_1=\arg \underset{w_i}{\min }\left|(w_i-w_{H_1}){(w_i-w_{H_1})}^{*}\right|$

Wherein superscript " * " is represented adjoint operator, | | the value that determinant is got in expression.

Expression is corresponding | | the code word of determinant absolute value minimum is chosen as the estimated value W of the sub-pre-encoding codeword of expectation ₁, corresponding pre-coding matrix index is PMI1, UE1 is to serving BS eNB1 feedback PMI1.Certainly, also can take other modes to calculate distance.

Similar, in the UE1 side, channel matrix H 2 is carried out singular value decomposition, obtain channel estimating code word matrix

Further obtain expecting sub-pre-encoding codeword W ₂:

$W_2=\arg \underset{w_i}{\min }\left|(w_i-w_{H_2}){(w_i-w_{H_2})}^{*}\right|$

Corresponding pre-coding matrix index is PMI2, and UE1 is to serving BS eNB1 feedback PMI2.

(4) estimate the phasing matrix, in the UE1 side, based on the signal power maximal criterion, calculate phasing matrix Θ according to channel matrix and the pre-coding matrix in this moment:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_2{W}_2\mathrm{\Θ})}^H(H_1{W}_1+H_2{W}_2\mathrm{\Θ})\right]$

Superscript " H " expression conjugate transpose operator wherein, tr[] expression asks the mark computing. $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_2{W}_2\mathrm{\Θ})}^H(H_1{W}_1+H_2{W}_2\mathrm{\Θ})\right]$ The Θ that represents corresponding mark maximum is chosen as the phasing matrix, and UE1 is to serving BS eNB1 feedback Θ.

(5) information interaction, serving BS eNB1 and cooperative base station eNB2 are by the interface between base station and base station (as X2 interface) interactive channel information, and namely base station eNB 1 is transmitted time delay number of samples τ, the phasing matrix Θ of pre-coding matrix index PMI2, minizone to base station eNB 2.

(6) the pre-encoding codeword phasing of cooperative base station and CDD coding

At base station eNB 2 ends, cooperative base station eNB2 is expressed as this phasing matrix behind the phasing matrix Θ that receives serving BS eNB1 transmission with the signal phase form

Wherein diag () represents diagonal matrix, θ ₁, θ ₂..., θ _mPhase correction factor for the corresponding number of plies.Phase correction factor and pre-coding matrix and data flow to be sent are multiplied each other, after then cooperative base station eNB2 proofreaies and correct transmit for:

To proofreading and correct back s _{1 proofreaies and correct}The symbol time-delay τ that circulates, be time delay τ at every antenna of time domain, be equivalent to the phase place rotation q τ/N on each subcarrier of frequency domain.Be that q subcarrier of frequency domain carries out phase-shift processing e ^{J2 π q τ/N}Wherein, N represents counting of inverse-Fourier transform, and q is sub-carrier indices (perhaps with the particular resource unit associated index).The transmission of whole like this OFDM (OFDM, Orthogonal FrequencyDivision Multiplexing) symbol does not lag behind in time, and cyclic shift has been carried out in an is-symbol inside.Above-mentioned s _{1 proofreaies and correct}Comprised precoding processing, if remove W ₂, then only represent the phasing processing.

Obtain cooperative base station eNB2 through behind the CDD coding transmit for:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

(7) serving BS eNB1 and cooperative base station eNB2 carry out signal s1 respectively to launch after the precoding, and then the reception signal of user UE1 end is:

$y=H_1{W}_1\·s_1+e^{j2\mathrm{\πq\τ}/N}\·H_2{W}_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Below in conjunction with example specific implementation process of the present invention is described in detail.

Method embodiment 1

This embodiment provides CoMP precoding implementation method under two cell scenario, eNB1 wherein, and the reception antenna number that the number of transmit antennas of eNB2 is 4, UE1 is 2, and the number of plies of UE1 is 2, as shown in Figure 2, comprises the steps:

As described in step 201, end side is carried out channel estimating, estimates the channel matrix H 1 between serving BS eNB1 and this community user UE1;

To cooperation cell eNB2, estimate the channel matrix H 2 between cooperation cell eNB2 and user UE1.

As described in step 202, estimate the time delay between different districts.

The different channels state information references pilot tone that user UE1 comprises according to same position in the signal resource piece of two residential quarters transmission estimates Serving cell respectively and cooperation cell sends data to the moment that reaches the user, again both is subtracted each other the delay inequality τ that obtains two minizones.τ=t ₂-t ₁, t wherein ₁, t ₂Be respectively the moment of serving BS eNB1 and cooperative base station eNB2 signal transmitted arrival user UE1.UE1 is to serving BS eNB1 feedback delay τ.

As described in step 203, the structure pre-encoding codeword.

In the UE1 side, choose code word, the code word w in the traversal code book from code book (as determining the LTE agreement) lining of precoding _i(wherein i is the code word sequence number in the corresponding code book),

Channel matrix H 1 is carried out singular value decomposition, namely

Obtain channel estimating code word matrix:

$W_{H_1}=V_{11,\left[m_k\right]}$

Wherein Be V ₁₁Preceding m _kRow, H1 is the N between UE1 and this cell base station eNB1 _k* M ties up channel matrix, U ₁₁Be N _k* M ties up unitary matrice, V ₁₁Be that M * M ties up unitary matrice, ε ₁₁=diag (σ ₁, σ ₂..., σ _r), r=rank (H ₁), diag represents diagonal matrix, the computing of rank () expression order, σ ₁, σ ₂..., σ _rIt is the singular value of channel matrix H 1.

Then travel through the channel estimating code word With code word w in the code book ₁Distance, code word apart from minimum be the expectation sub-pre-encoding codeword estimated value W ₁:

$W_1=\arg \underset{w_i}{\min }\left|(w_i-w_{H_1}){(w_i-w_{H_1})}^{*}\right|$

Wherein superscript " * " is represented adjoint operator, | | the value that determinant is got in expression.

Expression is corresponding | | the code word of determinant absolute value minimum is chosen as the estimated value W1 of the sub-pre-encoding codeword of expectation, and corresponding pre-coding matrix index is PMI1, and UE1 is to serving BS eNB1 feedback PMI1.

Similar, in the UE1 side, channel matrix H 2 is carried out singular value decomposition, obtain channel estimating code word matrix

Further obtain expecting sub-pre-encoding codeword W2:

$W_2=\arg \underset{w_i}{\min }\left|(w_i-w_{H_2}){(w_i-w_{H_2})}^{*}\right|$

Corresponding pre-coding matrix index is PMI2, and UE1 is to serving BS eNB1 feedback PMI2.

As described in step 204, estimate the phasing matrix, in the UE1 side, based on the signal power maximal criterion, calculate phasing matrix Θ according to channel matrix and the pre-coding matrix in this moment:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_2{W}_2\mathrm{\Θ})}^H(H_1{W}_1+H_2{W}_2\mathrm{\Θ})\right]$

Superscript " H " expression conjugate transpose operator wherein, tr[] expression asks the mark computing. $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_2{W}_2\mathrm{\Θ})}^H(H_1{W}_1+H_2{W}_2\mathrm{\Θ})\right]$ The Θ that represents corresponding mark maximum is chosen as the phasing matrix, and UE1 is to serving BS eNB1 feedback Θ.

As described in step 205, serving BS eNB1 and cooperative base station eNB2 are by the interface between base station and base station (as X2 interface) interactive channel information, and namely base station eNB 1 is transmitted time delay number of samples τ, the phasing matrix Θ of pre-coding matrix index PMI2, minizone to base station eNB 2.

As described in step 206, the pre-encoding codeword phasing of cooperative base station and CDD coding

At base station eNB 2 ends, cooperative base station is expressed as this phasing matrix behind the phasing matrix Θ that receives the serving BS transmission with the signal phase form

Wherein diag () represents diagonal matrix, θ ₁, θ ₂Phase correction factor for the corresponding number of plies.Phasing matrix and pre-coding matrix and data flow to be sent are multiplied each other, and the signal after then cooperative base station eNB2 proofreaies and correct is:

To proofreading and correct back s _{1 proofreaies and correct}The symbol time-delay τ that circulates, be time delay τ at every antenna of time domain, be equivalent to the phase place rotation q τ/N on each subcarrier of frequency domain.Be that q subcarrier of frequency domain carries out phase-shift processing e ^{J2 π q τ/N}Wherein, N represents counting of inverse-Fourier transform, and q is sub-carrier indices (perhaps with the particular resource unit associated index).The transmission of whole like this OFDM symbol does not lag behind in time, and cyclic shift has been carried out in an is-symbol inside.Certainly, also can directly carry out time domain time-delay τ.

Obtain cooperative base station eNB2 through behind the CDD coding transmit for:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2})$

As described in step 207, serving BS and cooperative base station carry out signal s1 respectively to launch after the precoding.

Then the reception signal of user UE1 end is:

$y=H_1{W}_1\·s_1+H_2\·e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2})$

Fig. 3 is the design sketch of implementing according to the CoMP precoding based on code book of the embodiment of the invention, and for serving BS eNB1, energy centralization is to this community user UE1 after the precoding; For cooperative base station eNB2, energy centralization is to user UE1 after the precoding.

Method embodiment 2

This embodiment provides CoMP precoding implementation method under K the cell scenario, eNB1 wherein, and eNB2 ..., it is 2 that the number of transmit antennas of eNBk is 4, UE1 reception antenna number, and the number of plies of each UE is 2, step is with embodiment 1:

Then the reception signal of user UE1 end is:

$y=H_1{W}_1\·s_1+H_2\·e^{j2\mathrm{\πq}{\mathrm{\τ}}_{21}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_{21}},e^{j{\mathrm{\θ}}_{22}})$

$+H_3\·e^{j2\mathrm{\πq}{\mathrm{\τ}}_{31}/N}\·W_3\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_{31}},e^{j{\mathrm{\θ}}_{32}})$

$....$

$+H_K\·e^{j2\mathrm{\πq}{\mathrm{\τ}}_{K1}/N}\·W_K\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_{K1}},e^{j{\mathrm{\θ}}_{K2}})$

Wherein, the delay inequality τ between serving BS eNB1 and cooperative base station eNB2 ₂₁, τ ₂₁=t ₂-t ₁, the delay inequality τ between serving BS eNB1 and cooperative base station eNBk _K1, τ _K1=t _K-t ₁t ₁, t ₂... t _KBe respectively serving BS eNB1, cooperative base station eNB2 ..., cooperative base station eNBk signal transmitted arrives the moment of user UE1.θ ₂₁, θ ₂₂Be the phase correction factor of the corresponding number of plies of cooperative base station eNB2, θ _K1, θ _K2Phase correction factor for the corresponding number of plies of cooperative base station eNBk.

Device embodiment

The embodiment of the invention provides a kind of terminal, as shown in Figure 4, comprising: channel estimation module 41, time delay estimation module 42, pre-encoding codeword constructing module 43, phasing matrix estimation module 44 and feedback module 45; Wherein:

Channel estimation module 41 is for the channel matrix that obtains between described terminal and serving BS, each cooperative base station; Such as, the channel matrix H 1 that estimating user UE1 and base station eNB are 1; The channel matrix H 2 that estimating user UE1 and base station eNB are 2.

Time delay estimation module 42 is connected to channel estimation module 41, arrives the time delay of described terminal for the signal that obtains serving BS and each cooperative base station; Concrete, according to the delay inequality between the delivery channel calculating different districts of channel estimation module 41.

Pre-encoding codeword constructing module 43 is connected to time delay estimation module 42, is used for obtaining each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

Phasing matrix estimation module 44 is used for obtaining the phasing matrix between described serving BS and each cooperative base station;

Feedback module 45 is used for giving described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

The embodiment of the invention also provides a kind of base station, as shown in Figure 5, comprising: information interaction module 51, phasing and coding module 52 and precoding processing module 53, wherein:

Information interaction module 51 is used for the information transmission between serving BS and cooperative base station; During as the cooperative base station of terminal, from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal in described base station; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station; During as the serving BS of terminal, time delay, phasing matrix and the pre-coding matrix index that receiving terminal sends also sends to corresponding cooperative base station in described base station;

Phasing and coding module 52 are connected to information interaction module 51, are used for cooperative base station is carried out pre-encoding codeword phasing and CDD coding; Be used for and carry out following processing to be sently for the signal of described terminal: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place and make it be equivalent to time domain to delay time, output signal to described precoding module; Specifically handle referring to method embodiment;

Precoding processing module 53 is connected to phasing and coding module 52, is used for carrying out precoding processing.Concrete, be used for using the pre-encoding codeword corresponding with described precoding index to carry out being emitted to described terminal after the precoding processing to the signal of phasing and precoding module output.

The realization function of each module of the above device is referring to the specific implementation process of said method, no longer praises at this and states.

One of ordinary skill in the art will appreciate that all or part of step in the said method can instruct related hardware to finish by program, described program can be stored in the computer-readable recording medium, as read-only memory, disk or CD etc.Alternatively, all or part of step of above-described embodiment also can use one or more integrated circuits to realize.Correspondingly, each the module/unit in above-described embodiment can adopt the form of hardware to realize, also can adopt the form of software function module to realize.The present invention is not restricted to the combination of the hardware and software of any particular form.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for those skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (12)

1. a precoding implementation method is characterized in that, comprising:

Terminal is obtained the channel matrix between itself and serving BS, each cooperative base station;

The signal that described terminal is obtained described serving BS and each cooperative base station reaches the time delay of described terminal;

Described terminal is obtained each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

Described terminal is obtained the phasing matrix between described serving BS and each cooperative base station;

Described terminal is given described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

2. the method for claim 1 is characterized in that, described terminal is obtained corresponding pre-encoding codeword according to channel matrix and comprised:

Described terminal is with channel matrix H _iCarry out singular value decomposition,

Extract V _IiPreceding m _kRow obtain channel estimating code word matrix

With in the predefine code book with described

The shortest code word of distance as described channel matrix H _iCorresponding pre-encoding codeword;

Wherein, described H _iBe the channel matrix between described terminal and the described serving BS, perhaps, be the channel matrix between described terminal and the described cooperative base station.

3. method as claimed in claim 1 or 2 is characterized in that, the phasing matrix that described terminal is obtained between described serving BS and each cooperative base station comprises:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$

Wherein, H ₁Be the channel matrix between described terminal and the described serving BS, W ₁Be H ₁Corresponding pre-encoding codeword, H _jBe the channel matrix between terminal and the cooperative base station, W _jBe H _jCorresponding pre-encoding codeword, tr[] expression asks the mark computing, $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$ Represent that the Θ of corresponding mark maximum is as described serving BS and described cooperative base station H _jBetween the phasing matrix.

4. a precoding implementation method is characterized in that, comprising:

The cooperative base station of terminal is from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, and described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station;

Described cooperative base station is carried out following processing with the signal of described terminal of giving to be sent: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place makes it be equivalent to the time domain time-delay, use the pre-encoding codeword corresponding with described precoding index to carry out precoding, the signal after handling is emitted to described terminal.

5. method as claimed in claim 4 is characterized in that, described use phasing matrix carries out phasing and comprises:

Wherein, s ₁Be the signal of giving described terminal to be sent,

It is the phasing matrix between described serving BS and the described cooperative base station.

6. as claim 4 or 5 described methods, it is characterized in that the described phasing matrix of described use carries out phasing, the pre-encoding codeword that carries out the rotation of frequency domain phase place and use described precoding index to obtain carries out precoding processing and comprises:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Wherein, s ₁Be the signal of giving described terminal to be sent, Be the phasing matrix, W ₂It is the pre-encoding codeword of described pre-coding matrix index correspondence, q be sub-carrier indices or with the particular resource unit associated index, N represents counting of inverse-Fourier transform, and τ is the time delay between described serving BS and the described cooperative base station, uses to postpone to count expression.

7. a terminal is characterized in that, comprising:

Channel estimation module is for the channel matrix that obtains between described terminal and serving BS, each cooperative base station;

The time delay estimation module, the signal that is used for obtaining described serving BS and each cooperative base station arrives the time delay of described terminal;

The pre-encoding codeword constructing module is used for obtaining each self-corresponding pre-encoding codeword according to each channel matrix, and, the pre-coding matrix index of described pre-encoding codeword correspondence;

The phasing matrix estimation module is used for obtaining the phasing matrix between described serving BS and each cooperative base station;

Feedback module is used for giving described serving BS with described time delay, pre-coding matrix index and phasing matrix feedback.

8. terminal as claimed in claim 7 is characterized in that, the pre-encoding codeword constructing module obtains corresponding pre-encoding codeword according to channel matrix and comprises:

With channel matrix H _iCarry out singular value decomposition,

Extract V _IiPreceding m _kRow obtain channel estimating code word matrix

With in the predefine code book with described

The shortest code word of distance as described channel matrix H _iCorresponding pre-encoding codeword;

Wherein, described H _iBe the channel matrix between described terminal and the described serving BS, perhaps, be the channel matrix between described terminal and the described cooperative base station.

9. as claim 7 or 8 described terminals, it is characterized in that the phasing matrix that described terminal is obtained between described serving BS and each cooperative base station comprises:

$\mathrm{\Θ}=\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$

Wherein, H ₁Be the channel matrix between described terminal and the described serving BS, W ₁Be H ₁Corresponding pre-encoding codeword, H _jBe the channel matrix between terminal and the cooperative base station, W _jBe H _jCorresponding pre-encoding codeword, tr[] expression asks the mark computing, $\arg \underset{\mathrm{\Θ}}{\max \mathrm{tr}}\left[{(H_1{W}_1+H_j{W}_j\mathrm{\Θ})}^H(H_1{W}_1+H_j{W}_j\mathrm{\Θ})\right]$ Represent that the Θ of corresponding mark maximum is as described serving BS and described cooperative base station H _jBetween the phasing matrix.

10. a base station is characterized in that, comprising:

The information interaction module, when being used in described base station the cooperative base station as terminal, from serving BS receive time delay, phasing matrix and the pre-coding matrix index of described terminal, described time delay is the time delay that the signal of described serving BS and described cooperative base station reaches described terminal; Described phasing matrix is the phasing matrix between described serving BS and the described cooperative base station, and described pre-coding matrix index is that described terminal feeds back to the described serving BS pre-coding matrix index corresponding with described cooperative base station;

Phasing and coding module, be used for the signal of described terminal of giving to be sent is carried out following processing: use described phasing matrix to carry out phasing, use described time delay to carry out time domain time-delay or the rotation of frequency domain phase place makes it be equivalent to the time domain time-delay, output signal to described precoding module;

Precoding module is used for using the pre-encoding codeword corresponding with described precoding index to carry out being emitted to described terminal after the precoding processing to the signal of phasing and precoding module output.

11. base station as claimed in claim 10 is characterized in that, described phasing and coding module use phasing matrix carry out phasing and comprise:

Wherein, s ₁Be the signal of giving described terminal to be sent,

It is the phasing matrix between described serving BS and the described cooperative base station.

12., it is characterized in that described precoding module is used the pre-encoding codeword corresponding with described precoding index to carry out being emitted to described terminal after the precoding processing to the signal of phasing and precoding module output to comprise as claim 10 or 11 described base stations:

$s_{1\mathrm{CDD}}=e^{j2\mathrm{\πq\τ}/N}\·W_2\·s_1\·\mathrm{diag}(e^{j{\mathrm{\θ}}_1},e^{j{\mathrm{\θ}}_2},...,e^{j{\mathrm{\θ}}_m})$

Wherein, s ₁Be the signal of giving described terminal to be sent, Be the phasing matrix, W ₂It is the pre-encoding codeword of described pre-coding matrix index correspondence, q be sub-carrier indices or with the particular resource unit associated index, N represents counting of inverse-Fourier transform, τ is the time delay between described serving BS and the described cooperative base station, use and postpone to count expression, s _1CDDSignal for precoding module output.

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