CN101986575B - Precoding method for multi-user multiple input multiple output (MIMO) system - Google Patents

Precoding method for multi-user multiple input multiple output (MIMO) system Download PDF

Info

Publication number
CN101986575B
CN101986575B CN 201010529044 CN201010529044A CN101986575B CN 101986575 B CN101986575 B CN 101986575B CN 201010529044 CN201010529044 CN 201010529044 CN 201010529044 A CN201010529044 A CN 201010529044A CN 101986575 B CN101986575 B CN 101986575B
Authority
CN
China
Prior art keywords
user
precoding
channel
matrix
pilot tone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN 201010529044
Other languages
Chinese (zh)
Other versions
CN101986575A (en
Inventor
李立华
张平
王化磊
高向川
宋磊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing University of Posts and Telecommunications
Original Assignee
Beijing University of Posts and Telecommunications
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing University of Posts and Telecommunications filed Critical Beijing University of Posts and Telecommunications
Priority to CN 201010529044 priority Critical patent/CN101986575B/en
Publication of CN101986575A publication Critical patent/CN101986575A/en
Application granted granted Critical
Publication of CN101986575B publication Critical patent/CN101986575B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

The invention discloses a precoding method for a multi-user multiple input multiple output (MIMO) system, which comprises the following steps: by the feedback of each user or the specific channel reciprocity of a time division duplexing system, acquiring channel information Hi of each user of the multi-user MIMO system and noise power i = 1, 2,...K, wherein K is the number of users of the multi-user MIMO system; according to the channel information Hi of each user, acquiring a compensation channel of each user and carrying out channel expansion, acquiring a matrix and carrying out LQ decomposition on the matrix, and acquiring a lower triangular matrix Li and a unitary matrix Qi; carrying out conjugate transpose on a submatrix of Qi and then multiplying by Hi to obtain an equivalent channel of each user; carrying out singular value decomposition (SVD) on the equivalent channel to obtain a precoding matrix Wi of each user; and precoding data and pilot frequency to be transmitted to each user by Wi, and transmitting the precoded data and pilot frequency to each user. Under the condition that a user terminal has multiple antennae, by using the method of the invention, the effects of two factors of interference and noise between multiple users on the system are eliminated, the performance of the multi-user MIMO system is improved, and the complexity of a transmitting terminal is reduced.

Description

The method for precoding of multi-user MIMO system
Technical field
The present invention relates to the wireless mobile telecommunication technology field, particularly a kind of method for precoding of multi-user MIMO system.
Background technology
Multiple-input and multiple-output (Multiple-Input Multiple-Output, MIMO) technology is the important breakthrough of wireless mobile communications art.The MIMO technology refers to that the sending and receiving of data has all adopted many antennas.Studies show that, utilize the MIMO technology can improve the capacity of wireless communication system.Along with going deep into of multi-antenna technology research, the MIMO technology is from point-to-point Single User MIMO technological expansion to the multi-user MIMO system of point-to-multipoint (Multiple User MIMO, MU-MIMO).In the MU-MIMO technology, the multi-antenna diversity gain can effectively reduce error rate of system, and multi-antenna multiplexed gain enlarges the multi-user system capacity region.MU-MIMO adopts the transmitting terminal precoding technique usually, utilizes space division multiple access (Spatial Division Multiple Access, SDMA) technology to transmit a plurality of users' information in same time, frequency resource.
In the MU-MIMO system, to a plurality of user sides transmissions data separately, a plurality of users share same running time-frequency resource simultaneously in the base station, the common road that certainly exists in the system between the user disturbs (Co-Channel Interference, CCI), so CCI is the same with noise, has affected widely the performance of system.Technology is suggested the elimination multiuser interference to broken zero channel reverse (Zero forcing channel inversion, ZF-CI), but it does not but consider the impact of noise, and its to be only applicable to each user of receiving terminal be 1 antenna.Least mean-square error channel reverse (Minimummean-squared error channel inversion, MMSE-CI) considered that noise and multiuser interference are on the impact of systematic function, but the same with ZF-CI, be only suitable in each user of receiving terminal a reception antenna being arranged.Block of channels diagonalization (Block Diagonolization, BD) precoding technique be suggested the interference of eliminating fully between the user, and each user of receiving terminal can have the antenna more than 1.But the BD technology must be satisfied with the antenna number of transmitting terminal and count sum more than or equal to all users' reception antenna, thereby BD technology and be not suitable for the situation that each user of receiving terminal has any root reception antenna.And the BD technology has just been eliminated the interference between the user, does not consider noise to the impact of systematic function, thereby when signal to noise ratio reduced, its Performance Ratio was relatively poor.In order to improve the performance of BD, RBD(regularized BD) technology is suggested, however its complexity is too high, realizes that in reality this technology is very difficult.
Summary of the invention
The technical problem that (one) will solve
The technical problem to be solved in the present invention is: how to make each user of MU-MIMO system that any root reception antenna is arranged, and reduce CCI and noise to the impact of system, improve systematic function, especially make improvement more obvious when noise is larger.
(2) technical scheme
For solving the problems of the technologies described above, the invention provides a kind of method for precoding of multi-user MIMO system, may further comprise the steps:
S101: by each user feedback or utilize the channel reciprocity of tdd systems, obtain the channel information H of each user in described multi-user's multiple-input and multiple-output mimo system iAnd noise power
Figure GDA00002656846200021
I=1,2 ... K, K represent the number of users of multi-user MIMO system;
S102: according to each user's channel information H i, obtain each user's benefit channel
Figure GDA00002656846200022
And to its enforcement channel expansion, obtain matrix
Figure GDA00002656846200023
S103: to matrix
Figure GDA00002656846200024
Implement LQ and decompose, obtain lower triangular matrix L iWith unitary matrice Q i
S104: with Q iThe submatrix of the capable N of N row
Figure GDA00002656846200025
The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure GDA00002656846200026
N is the transmitting terminal antenna number;
S105: to each user's equivalent channel
Figure GDA00002656846200027
Implement the SVD operation splitting, obtain each user's pre-coding matrix W i
S106: utilize described pre-coding matrix W iData and the pilot tone that will send to each user are carried out precoding, and the data after the precoding and pilot tone are sent to each user.
Wherein, obtain each user's channel information H among the described step S101 by each user feedback iComprise step:
Transmitting terminal sends the descending pilot frequency of non-precoding;
Each user utilizes described descending pilot frequency information to carry out channel estimating;
Each user utilizes the estimated channel information that goes out of described descending pilot frequency to transmitting terminal feedback;
Transmitting terminal receives the channel information of each user feedback, thereby obtains each user's of system channel information H i
Wherein, obtain each user's channel information H among the described step S101 by tdd systems iComprise step:
User side sends the ascending pilot frequency of non-precoding;
Transmitting terminal utilizes described ascending pilot frequency to carry out channel estimating, obtains uplink channel information, according to the up-downgoing channel reciprocity of tdd systems, obtains descending channel information.
Wherein, described step S102 specifically comprises:
Channel information H according to described each user i, the channel information of acquisition multi-user MIMO system
Figure GDA00002656846200031
Each user's benefit channel H ‾ i = ( H 1 T , . . . , H i - 1 T , H i + 1 T , . . . H k T ) T .
Benefit channel to each user
Figure GDA00002656846200033
Implement channel expansion, obtain matrix Wherein
Figure GDA00002656846200035
The expression noise factor, wherein, ∂ = Σ k = 1 , k ≠ i K M k × σ i , w 2 , I is Unit matrix, M kThe reception antenna number of expression user k.
Wherein, obtain each user's equivalent channel among the described step S104
Figure GDA00002656846200038
Mode be:
Choose by Q iFront N row and the submatrix of the capable element composition of rear N
Figure GDA00002656846200039
Will The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure GDA000026568462000311
Wherein, described step S105 comprises step:
Right
Figure GDA000026568462000312
According to the SVD decomposition formula
Figure GDA000026568462000313
Carry out operation splitting, wherein U iBe left unitary matrice, Λ iBe diagonal matrix, V iBe right unitary matrice, V I, 1By V iFront M iRow form, V I, 0By V iRear N-M iRow form,
Figure GDA000026568462000314
Representing matrix V iThe complex-conjugate transpose matrix, M iThe reception antenna number of expression user i, N represents the antenna number of transmitting terminal.
According to
Figure GDA000026568462000315
Obtain pre-coding matrix W i
Wherein, described step S106 is specially:
With the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of the first pilot tone i, not precoding the second pilot tone, and the first pilot tone after the data after the second pilot tone, the precoding and the precoding sent to each user.
Wherein, also comprise step after the described step S106:
Each user utilizes respectively oneself antenna reception the second pilot tone, the data after the precoding and the first pilot tone after the precoding, and utilizes the first pilot tone after the precoding to carry out channel estimating, obtains the channel that is used for decoding separately
Figure GDA00002656846200041
Be actual channel and described pre-coding matrix W iProduct, i=1,2 ... K;
Utilize
Figure GDA00002656846200042
And adopt broken zero criterion that the pre-code data that receives is deciphered, data after obtaining to decipher;
Utilize the second pilot tone of not precoding to carry out channel estimating, obtain the channel information H for feedback i
Wherein, described step S106 is specially:
With the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of pilot tone i, and the data after the precoding and the pilot tone after the precoding are sent to each user.
Wherein, also comprise step after the described step S106:
Each user utilizes respectively data after oneself the antenna reception precoding and the pilot tone after the precoding, and utilizes the pilot tone after the precoding to carry out channel estimating, obtains the channel that is used for decoding separately
Figure GDA00002656846200043
Be actual channel and described pre-coding matrix W iProduct, i=1,2 ... K;
Utilize
Figure GDA00002656846200044
And the data after adopting broken zero criterion to the precoding that receives are deciphered the data after obtaining to decipher.
(3) beneficial effect
The present invention has in the situation of many antennas at user side, adopt above-mentioned precoding step, these two factors of multiuser interference and noise have been got rid of to the impact of system, improved the multi-user MIMO system performance, reduce the complexity of transmitting terminal, thereby promoted the method feasibility in actual applications.
Description of drawings
Fig. 1 is the method for precoding flow chart of the multi-user MIMO system of one embodiment of the invention;
Fig. 2 is the method for precoding flow chart of the multi-user MIMO system of another embodiment of the present invention;
Fig. 3 is the MU-MIMO system model schematic diagram of method in the application drawing 1, wherein, and transmitting terminal utilization feedback acquisition each user's of system channel information;
Fig. 4 is the MU-MIMO system model schematic diagram of method in the application drawing 2, and wherein, transmitting terminal utilizes the channel reciprocity of TDD system to obtain each user's of system channel information;
Fig. 5 has provided under the condition of different signal to noise ratios, based on method for precoding of the present invention with based on BD, and the capacity comparative graph of the multi-user MIMO system of RBD method for precoding;
Fig. 6 has provided in signal to noise ratio during for-6dB, based on method for precoding of the present invention with based on BD, and the capacity cumulative distribution function comparative graph of the multi-user MIMO system of RBD method for precoding;
Fig. 7 has provided when signal to noise ratio is 15dB, based on method for precoding of the present invention with based on BD, and the capacity cumulative distribution function comparative graph of the multi-user MIMO system of RBD method for precoding.
Embodiment
Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used for explanation the present invention, but are not used for limiting the scope of the invention.
Below utilize feedback to obtain Frequency Division Duplexing (FDD) (the Frequency DivisionDuplexing of channel information, FDD) MU-MIMO system, and time division duplex (Time Division Duplexing, TDD) the MU-MIMO system that utilizes the up-downgoing pilot frequency information to obtain channel information is that the present invention is described in detail for example.
Embodiment 1
As shown in Figure 1, obtain the method for precoding flow chart of channel information for utilizing user feedback, the method comprises:
Step S101 by each user feedback, obtains described each user's of multi-user MIMO system channel information H iAnd noise power
Figure GDA00002656846200061
I=1,2 ... K, K represent the number of users of multi-user MIMO system.Concrete obtaining step is:
Transmitting terminal sends the descending pilot frequency of non-precoding;
Each user side utilizes descending pilot frequency information to carry out channel estimating;
Each user side utilizes the estimated channel information that goes out of descending pilot frequency to base station feedback;
The base station receives the channel information of each user feedback, thereby obtains each user's of system channel information H i
Step S102 is according to each user's channel information H i, obtain each user's benefit channel
Figure GDA00002656846200062
The benefit channel of user i is made of the channel of other all users except user i in the multi-user MIMO system, and it is implemented channel expansion, obtains matrix
Figure GDA00002656846200063
Particularly, according to described each user's channel information H i, the channel information that obtains multi-user MIMO system is
Figure GDA00002656846200064
Each user's benefit channel is H ‾ i = ( H 1 T , . . . , H i - 1 T , H i + 1 T , . . . H k T ) T , T represents transposition.
Benefit channel to each user Implement channel expansion, obtain matrix
Figure GDA00002656846200067
Wherein
Figure GDA00002656846200068
The expression noise factor, wherein, ∂ = Σ k = 1 , k ≠ i K M k × σ i , w 2 , I is
Figure GDA000026568462000610
Unit matrix, M kThe reception antenna number of expression user k.By inciting somebody to action
Figure GDA000026568462000611
Be placed on
Figure GDA000026568462000612
The right, (common method of the prior art is to be placed on The below), so that matrix
Figure GDA000026568462000614
Dimension become
Figure GDA000026568462000615
Obviously its columns is greater than its line number, and then guaranteed to obtain
Figure GDA000026568462000616
The dimension requirement of kernel.By
Figure GDA000026568462000617
The form of the composition as can be known, it has considered to cause the element that affects of multiuser interference simultaneously
Figure GDA000026568462000618
And noise
Figure GDA000026568462000619
N is the transmitting terminal antenna number.Thereby present embodiment is suitable for the MU-MIMO pre-coding system that each user of receiving terminal has any reception antenna.
Step S103 is to matrix
Figure GDA000026568462000620
Implement LQ and decompose, obtain lower triangular matrix L iWith unitary matrice Q i, decompose to obtain triangular matrix L by adopting LQ iWith unitary matrice Q i, reduced the complexity of transmitting terminal.
Step S104 is with Q iRear N capable before the submatrix of N row
Figure GDA000026568462000621
The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure GDA000026568462000622
N is the transmitting terminal antenna number.Particularly, choose Q iFront N row and the capable unit of rear N usually form submatrix
Figure GDA00002656846200071
And will
Figure GDA00002656846200072
The conjugate transpose right side take advantage of in H i, and then obtain each user's equivalent channel
Figure GDA00002656846200073
Step S105 is to each user's equivalent channel Implement the SVD operation splitting, obtain each user's pre-coding matrix W iSpecifically comprise:
Right
Figure GDA00002656846200075
According to the SVD decomposition formula
Figure GDA00002656846200076
Carry out operation splitting, wherein U iBe left unitary matrice, Λ iBe diagonal matrix, V iBe right unitary matrice, V I, 1By V iFront M iRow form,
Figure GDA00002656846200077
Representing matrix V iThe complex-conjugate transpose matrix, V I, 0By V iRear N-M i(N subtracts M i) the row composition, M iThe reception antenna number of expression user i, N is the antenna number of transmitting terminal.
According to
Figure GDA00002656846200078
Obtain pre-coding matrix W i
Step S106 utilizes described pre-coding matrix W iData and first pilot tone that will send to each user are carried out precoding, be about to the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of the first pilot tone i, the second pilot tone is not carried out precoding, and the first pilot tone after the data after the second pilot tone, the precoding and the precoding is sent to each user.
After the data and the first pilot tone after the precoding after transmitting terminal sends above-mentioned the second pilot tone, precoding, each user utilizes respectively antenna reception the second pilot tone, the data after the precoding and the first pilot tone after the precoding of oneself, and utilize the first pilot tone after the precoding to carry out channel estimating, obtain the channel that is used for decoding separately
Figure GDA00002656846200079
Be actual channel and pre-coding matrix W iProduct, preferred premultiplication is in W i, actual channel is actual physical channel, i=1, and 2 ... K utilizes
Figure GDA000026568462000710
And adopt ZF (Zero forcing, ZF) criterion that the pre-code data that receives is deciphered, obtain the rear data of decoding; Utilize the second pilot tone of not precoding to carry out channel estimating, obtain the channel information H for feedback i
As shown in Figure 2, be the FDD MU-MIMO system model of the step S101 that utilizes said method ~ S106.If FDD MU-MIMO system comprise 1 base station and K user (user 1, and the user 2 ..., user K), transmitting terminal has the M transmit antennas, and user i has M iThe root reception antenna.W among the figure iBe the pre-coding matrix of user i,
Figure GDA000026568462000711
Be the noise of user i, X iFor sending to the data of user i, y iBe the receive data of user i, Z iBe the data after the user i decoding, H iChannel information for feedback.
Embodiment 2
As shown in Figure 3, obtain the method for precoding flow chart of channel information for utilizing the TDD system, the method comprises:
Step S301 by the distinctive channel reciprocity of TDD system, obtains described each user's of multi-user MIMO system channel information H iAnd noise power
Figure GDA00002656846200081
I=1,2 ... K, K represent the number of users of multi-user MIMO system.Concrete obtaining step is:
User side sends the ascending pilot frequency of non-precoding;
Transmitting terminal utilizes described ascending pilot frequency to carry out channel estimating, obtains uplink channel information, according to tdd systems up-downgoing channel reciprocity, obtains descending channel information, and it is uplink channel information.
Step S302 is according to each user's channel information H i, obtain each user's benefit channel And to its enforcement channel expansion, obtain matrix
Figure GDA00002656846200083
Particularly, according to described each user's channel information H i, the channel information that obtains multi-user MIMO system is
Figure GDA00002656846200084
Each user's benefit channel H ‾ i = ( H 1 T , . . . , H i - 1 T , H i + 1 T , . . . H k T ) T , T represents transposition.
Benefit channel to each user
Figure GDA00002656846200086
Implement channel expansion, obtain matrix
Figure GDA00002656846200087
Wherein
Figure GDA00002656846200088
The expression noise factor, wherein, ∂ = Σ k = 1 , k ≠ i K M k × σ i , w 2 , I is
Figure GDA000026568462000810
Unit matrix, M kThe reception antenna number of expression user k.To by described
Figure GDA000026568462000811
Be placed on
Figure GDA000026568462000812
The right, (common method of the prior art is to be placed on The below), so that matrix
Figure GDA000026568462000814
Dimension become Obviously its columns is greater than its line number, and then guaranteed to obtain
Figure GDA000026568462000816
The dimension requirement of kernel.By
Figure GDA000026568462000817
The form of the composition as can be known, it has considered to cause the element that affects of multiuser interference simultaneously
Figure GDA000026568462000818
And noise
Figure GDA000026568462000819
Thereby present embodiment is suitable for the MU-MIMO pre-coding system that each user of receiving terminal has any reception antenna.
Step S303 is to matrix
Figure GDA000026568462000820
Implement LQ and decompose, obtain lower triangular matrix L iWith unitary matrice Q i, decompose to obtain triangular matrix L by adopting LQ iWith unitary matrice Q i, reduced the complexity of transmitting terminal.
Step S304 is with Q iRear N capable before the submatrix of N row
Figure GDA000026568462000821
The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure GDA00002656846200091
N is the transmitting terminal antenna number.Particularly, choose Q iFront N row and the capable unit of rear N usually form submatrix
Figure GDA00002656846200092
And will
Figure GDA00002656846200093
The conjugate transpose right side take advantage of in H i, and then obtain each user's equivalent channel
Step S305 is to each user's equivalent channel
Figure GDA00002656846200095
Implement the SVD operation splitting, obtain each user's pre-coding matrix W iSpecifically comprise:
Right
Figure GDA00002656846200096
According to the SVD decomposition formula
Figure GDA00002656846200097
Carry out operation splitting, wherein U iBe left unitary matrice, Λ iBe diagonal matrix, V iBe right unitary matrice, V I, 1By V iFront M iRow form,
Figure GDA00002656846200098
Representing matrix V iThe complex-conjugate transpose matrix, V I, 0By V iRear N-M i(N subtracts M i) the row composition, M iThe reception antenna number of expression user i, N is the antenna number of transmitting terminal.
According to
Figure GDA00002656846200099
Obtain pre-coding matrix W i
Step S306 utilizes described pre-coding matrix W iData and the pilot tone that will send to each user are carried out precoding, with the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of pilot tone i, and the data after the precoding and the pilot tone after the precoding are sent to each user.
After the data and the pilot tone after the precoding after transmitting terminal sends above-mentioned precoding, each user utilizes respectively data after oneself the antenna reception precoding and the pilot tone after the precoding, and utilize the pilot tone after the precoding to carry out channel estimating, obtain the channel that is used for decoding separately
Figure GDA000026568462000910
Be actual channel and pre-coding matrix W iProduct, preferred premultiplication is in W i, actual channel is actual physical channel, i=1, and 2 ... K; Utilize
Figure GDA000026568462000911
And the data after adopting broken zero (Zero forcing:ZF) criterion to the precoding that receives are deciphered the data after obtaining to decipher.
As shown in Figure 4, for utilizing the TDD MU-MIMO system model of said method step S301 ~ S306.If TDD MU-MIMO system comprise 1 base station and K user (user 1, and the user 2 ..., user K), there is the M transmit antennas base station, and user i has M iThe root reception antenna.W among the figure iBe the pre-coding matrix of user i,
Figure GDA000026568462000912
Be the noise of user i, X iFor sending to the data of user i, y iBe the receive data of user i, Z iBe the data after the user i decoding.
The below will provide the comparison of pre-coding scheme of the present invention and existing other pre-coding scheme, so that advantage of the present invention and feature are more obvious.
To the real matrix of a m * n, the complexity that its SVD decomposes is 4n 2M+13m 3(flops), the complexity of its LQ decomposition is 2m 2(n-m/3) (flops).For the ease of simply, just illustrate as an example of real matrix example here.
Suppose that there be K user in system, each user has identical reception antenna to count M i=M,
Figure GDA00002656846200101
And the fluxion of supposing every user transmission is 1, being compared as follows shown in the table 1 of the complexity of precoding algorithm of the present invention and existing precoding.
The complexity of table 1 precoding algorithm of the present invention and existing precoding relatively
Figure GDA00002656846200102
As shown in Table 1, with traditional method for multi-user pre-coding, BD for example, RBD compares, and technical solution of the present invention greatly reduces the computational complexity of sending out receiving end, and this will be conducive to method of the present invention application in practice.
In addition, as shown in Figure 5, show system (2,2,2) * 6 based on method for precoding of the present invention with based on BD, the capacity comparative graph of the multi-user MIMO system of RBD method for precoding, this system have 3 users, each user has 2 reception antennas, transmitting terminal has 6 transmitting antennas, and receiving terminal all adopts ZF to detect, under different signal to noise ratio conditions, based on multi-user pre-coding system of the present invention and BD, the emulation comparison diagram of the capacity of the multi-user pre-coding system of RBD.As seen from Figure 5, pre-coding scheme of the present invention is compared with the BD scheme, can well improve the signal to noise ratio of system, thereby improves the capacity of system.Pre-coding scheme of the present invention is compared with RBD, obtains same performance, but as shown in table 1, the solution of the present invention complexity is significantly less than the complexity of RBD scheme.Same condition, system have 3 users, and each user has 2 reception antennas, and transmitting terminal has 6 transmitting antennas, shown in Fig. 6 and 7, have provided the capacity C DF curve chart relatively of method of the present invention and BD, and it has further shown performance advantage of the present invention.And as shown in table 1, to compare with BD, the solution of the present invention has lower complexity.
Above execution mode only is used for explanation the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; in the situation that does not break away from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (7)

1. the method for precoding of a multi-user MIMO system is characterized in that, may further comprise the steps:
S101: by each user feedback or utilize the channel reciprocity of tdd systems, obtain the channel information H of each user in described multi-user's multiple-input and multiple-output mimo system iAnd noise power
Figure FDA00002465206900011
I=1,2 ... K, K represent the number of users of multi-user MIMO system;
S102: according to each user's channel information H i, obtain each user's benefit channel
Figure FDA00002465206900012
And to its enforcement channel expansion, obtain matrix
Figure FDA00002465206900013
S103: to matrix
Figure FDA00002465206900014
Implement LQ and decompose, obtain lower triangular matrix L iWith unitary matrice Q i
S104: with Q iThe submatrix of the capable N of N row
Figure FDA00002465206900015
The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure FDA00002465206900016
N is the transmitting terminal antenna number;
S105: to each user's equivalent channel
Figure FDA00002465206900017
Implement the SVD operation splitting, obtain each user's pre-coding matrix W i
S106: utilize described pre-coding matrix W iData and the pilot tone that will send to each user are carried out precoding, and the data after the precoding and pilot tone are sent to each user;
Described step S102 specifically comprises:
Channel information H according to described each user i, the channel information of acquisition multi-user MIMO system
Figure FDA00002465206900018
Each user's benefit channel H ‾ i = ( H 1 T , · · · , H i - 1 T , H i + 1 T , · · · H k T ) T ;
Benefit channel to each user
Figure FDA000024652069000110
Implement channel expansion, obtain matrix
Figure FDA000024652069000111
Wherein The expression noise factor, wherein, ∂ = Σ k = 1 , k ≠ i K M k × σ i , w 2 , I is Σ k = 1 , k ≠ i K M k × Σ k = 1 , k ≠ i K M k Unit matrix, M kThe reception antenna number of expression user k;
Obtain each user's equivalent channel among the described step S104
Figure FDA000024652069000115
Mode be:
Choose by Q iFront N row and the submatrix of the capable element composition of rear N
Figure FDA000024652069000116
Will The associate matrix right side take advantage of in H i, obtain each user's equivalent channel
Figure FDA000024652069000118
Described step S105 comprises step:
Right
Figure FDA000024652069000119
According to the SVD decomposition formula Carry out operation splitting, wherein U iBe left unitary matrice, Λ iBe diagonal matrix, V iBe right unitary matrice, V I, 1By V iFront M iRow form, V I, 0By V iRear N-M iRow form,
Figure FDA00002465206900021
Representing matrix V iThe complex-conjugate transpose matrix, M iThe reception antenna number of expression user i, N represents the antenna number of transmitting terminal;
According to
Figure FDA00002465206900022
Obtain pre-coding matrix W i
2. the method for precoding of multi-user MIMO system as claimed in claim 1 is characterized in that, obtains each user's channel information H among the described step S101 by each user feedback iComprise step:
Transmitting terminal sends the descending pilot frequency of non-precoding;
Each user utilizes described descending pilot frequency information to carry out channel estimating;
Each user utilizes the estimated channel information that goes out of described descending pilot frequency to transmitting terminal feedback;
Transmitting terminal receives the channel information of each user feedback, thereby obtains each user's of system channel information H i
3. the method for precoding of multi-user MIMO system as claimed in claim 1 is characterized in that, obtains each user's channel information H among the described step S101 by tdd systems iComprise step:
User side sends the ascending pilot frequency of non-precoding;
Transmitting terminal utilizes described ascending pilot frequency to carry out channel estimating, obtains uplink channel information, according to the up-downgoing channel reciprocity of tdd systems, obtains descending channel information.
4. the method for precoding of multi-user MIMO system as claimed in claim 1 or 2 is characterized in that, described step S106 is specially:
With the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of the first pilot tone i, not precoding the second pilot tone, and the first pilot tone after the data after the second pilot tone, the precoding and the precoding sent to each user.
5. the method for precoding of multi-user MIMO system as claimed in claim 4 is characterized in that, also comprises step after the described step S106:
Each user utilizes respectively oneself antenna reception the second pilot tone, the data after the precoding and the first pilot tone after the precoding, and utilizes the first pilot tone after the precoding to carry out channel estimating, obtains the channel that is used for decoding separately
Figure FDA00002465206900031
Be actual channel and described pre-coding matrix W iProduct, i=1,2 ... K;
Utilize
Figure FDA00002465206900032
And adopt broken zero criterion that the pre-code data that receives is deciphered, data after obtaining to decipher;
Utilize the second pilot tone of not precoding to carry out channel estimating, obtain the channel information H for feedback i
6. such as the method for precoding of claim 1 or 3 described multi-user MIMO systems, it is characterized in that described step S106 is specially:
With the described data X that will send to each user iReach the respectively right pre-coding matrix W that takes advantage of in each user of pilot tone i, and the data after the precoding and the pilot tone after the precoding are sent to each user.
7. the method for precoding of multi-user MIMO system as claimed in claim 6 is characterized in that, also comprises step after the described step S106:
Each user utilizes respectively data after oneself the antenna reception precoding and the pilot tone after the precoding, and utilizes the pilot tone after the precoding to carry out channel estimating, obtains the channel that is used for decoding separately
Figure FDA00002465206900033
Be actual channel and described pre-coding matrix W iProduct, i=1,2 ... K;
Utilize
Figure FDA00002465206900034
And the data after adopting broken zero criterion to the precoding that receives are deciphered the data after obtaining to decipher.
CN 201010529044 2010-10-28 2010-10-28 Precoding method for multi-user multiple input multiple output (MIMO) system Expired - Fee Related CN101986575B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201010529044 CN101986575B (en) 2010-10-28 2010-10-28 Precoding method for multi-user multiple input multiple output (MIMO) system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 201010529044 CN101986575B (en) 2010-10-28 2010-10-28 Precoding method for multi-user multiple input multiple output (MIMO) system

Publications (2)

Publication Number Publication Date
CN101986575A CN101986575A (en) 2011-03-16
CN101986575B true CN101986575B (en) 2013-05-29

Family

ID=43710883

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 201010529044 Expired - Fee Related CN101986575B (en) 2010-10-28 2010-10-28 Precoding method for multi-user multiple input multiple output (MIMO) system

Country Status (1)

Country Link
CN (1) CN101986575B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102404088A (en) * 2011-07-21 2012-04-04 京信通信系统（中国）有限公司 Multi-user diversity method and device based on linear discrete codes
CN102412933B (en) * 2011-11-30 2014-10-15 北京邮电大学 Precoding method and matrix generating device of CoMP (coordinated multi-point) multiple-user MIMO (multiple-input multi output) system
CN102404090B (en) * 2012-01-02 2014-04-16 西安电子科技大学 Downlink transmission method for multi-user MIMO (Multiple Input Multiple Output) system based on singular value decomposition
CN103297102B (en) * 2012-03-02 2017-11-21 北京新岸线移动多媒体技术有限公司 The pre-coding matrix of wave beam forming provides and preparation method, apparatus and system
CN103220034B (en) * 2013-05-14 2016-03-30 郑州轻工业学院 The method of the cognitive mimo system concurrent transmission of the multi-user based on IAC and user scheduling
CN111371478B (en) * 2018-12-26 2021-10-15 华为技术有限公司 Precoding method and device and information transmission method and device
CN111614397B (en) * 2020-05-22 2022-07-26 南京邮电大学 High-altitude unmanned platform communication system and multi-antenna wireless transmission method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101686073A (en) * 2008-09-22 2010-03-31 大唐移动通信设备有限公司 Pre-coding power normalization parameter transmitting and receiving method and equipment

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101584689B1 (en) * 2009-03-04 2016-01-13 삼성전자주식회사 Apparatus and method for interference cancellation of multi user in multi-antenna system
US8363587B2 (en) * 2009-03-23 2013-01-29 Qualcomm Incorporated Signaling methods for MMSE precoding with eigenmode selection

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101686073A (en) * 2008-09-22 2010-03-31 大唐移动通信设备有限公司 Pre-coding power normalization parameter transmitting and receiving method and equipment

Also Published As

Publication number Publication date
CN101986575A (en) 2011-03-16

Similar Documents

Publication Publication Date Title
CN101984571B (en) Pre-coding method for multi-user MIMO system
CN102104404B (en) Multi-user MIMO transmission method in wireless communication system, base station and user terminal
CN101986575B (en) Precoding method for multi-user multiple input multiple output (MIMO) system
CN102983934B (en) The method of multiuser mimo system neutral line precoding and device
CN103957086B (en) MU MIMO precoding implementation methods
CN101252383B (en) System and method of multi-user multi-aerial transmission
CN103312390B (en) Based on the method for precoding of interference alignment, emitter and equipment
CN103312389A (en) Multiuser interference suppression method, terminal and base station
CN102315872B (en) Transmission method of non-codebook pre-coding in long term evolution-advanced (LTE-A) system
CN102546488B (en) Interference elimination method based on effective channel parameter semi-orthogonal
US8218668B2 (en) Multi-user MIMO method, apparatus and communication system for transmitting signal
CN102158270B (en) Sub-channel selecting and pre-code sending method of multi-user MIMO (Multiple Input Multiple Output) system
CN101917218A (en) MIMO multi-user system downlink transmission method and system for reducing feedback information
CN102412933B (en) Precoding method and matrix generating device of CoMP (coordinated multi-point) multiple-user MIMO (multiple-input multi output) system
CN103384228A (en) Continuous pre-coding and user selection united algorithm for multi-user MIMO (Multiple-Input Multiple-Output) broadcast channel
CN101873190B (en) Pre-coding method and device
CN103607260B (en) System total interference leakage minimum pre-coding matrix group selection algorithm based on MIMO
CN103236878B (en) A kind of coordinates beam shaping method receiving vector estimation based on maximum-ratio combing
Song et al. Flexible coordinated beamforming (FlexCoBF) for the downlink of multi-user MIMO systems in single and clustered multiple cells
CN102752071A (en) Down-link pre-encoding method used for multipoint cooperative system and central processing node
CN102006146A (en) User scheduling method for multiple-user multiple input multiple output (MU-MIMO) system downlink
CN101953088B (en) Orthogonal projection precoding and decoding method and equipment by using part CSI feedback
CN102710371B (en) Transmission method using limiting feedback information in multi-antenna two-hop relay system
CN101958852B (en) Method and device for estimating CINR of MLD receiver in MIMO system
Lejosne et al. Space time interference alignment scheme for the MIMO BC and IC with delayed CSIT and finite coherence time

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20130529

Termination date: 20141028

EXPY Termination of patent right or utility model