CN106209191A - A kind of MU mimo system true environment low complex degree user choosing method - Google Patents

Abstract

The present invention relates to a kind of MU mimo system true environment low complex degree user choosing method, it is analyzed based on real wireless transmission environments (rich scattering and non-lipid scattering all exist), obtain the dynamic capacity upper limit that user selects in non-lipid scattering environments, and made a concrete analysis of the change that user's equivalent channel matrix dimension and order select the increase of iteration to be occurred along with user, and by this change application to user's selection reference；Additionally, user's equivalent channel matrix be multiplied with its conjugate matrices nonzero eigenvalue of the matrix obtained of the present invention is long-pending, i.e. low complex degree token state is as user's selection reference, the admissible rate of user can be characterized to a certain extent, this product value can be obtained by last iterative value recurrence, reduce the computation complexity of algorithm, simultaneously on the basis of the differentiated service QoS that becomes more meticulous, improve the effective throughput of system.

Description

A kind of MU-MIMO system true environment low complex degree user choosing method

Technical field

The present invention relates to a kind of MU-MIMO system true environment low complex degree user choosing method, belong to communication technology neck Territory.

Background technology

Along with the requirement that people are the highest to the transfer rate of radio communication and service quality, multiple-input and multiple-output (Multiple-Input Multiple-Output, MIMO) technology receives the concern of more and more people.Wherein, multi-user MIMO (MU-MIMO) technology can not increase by effectively utilizing spatial degrees of freedom (Degree of Freedom, DoF) Significantly improved the handling capacity of wireless communication system by space division on the premise of frequency resource.

In multi-user MIMO system, only by partition space resource when multiple users transmit data, due to space The data overlap of upper different user, then inevitably cause multi-user interference.For making different transmitting transmit on antenna Signal between can be mutually distinguishable, and receiver can distinguish the sub data flow that these are parallel, it would be desirable to provides foot Enough spatial degrees of freedom make between user's subchannel mutually orthogonal, do not interfere with each other.And spatial degrees of freedom is in mimo systems It is embodied in the Base Transmitter number of antennas that energy is separate.The limited number making space channel of number of antennas also receives limit System.And in actual applications, owing to IPization business has sudden (activity factor of such as voice service is 0.47), for improving The service efficiency of confined space resource, the number of users of access is greater than the number of users that system can communicate simultaneously.Sudden industry Business user can be with statistic multiplexing space resources, in this case, carries out user's selection the most efficiently so that system Best performance becomes a study hotspot.

The most most of documents are when studying user choosing method, it is thus necessary to determine that the user capacity upper limit and user choose base Standard, common problem is: 1), the most only consider the situation that mimo channel is under rich scattering environments, the i.e. letter of user antenna Road matrix is all in the separate state of channel between full rank and user.But the wireless transmission environments of reality is not necessarily fully Scattering, so consider that user antenna channel matrix is in what the situation of full rank or non-full rank was a need for simultaneously.2), existing When studying based on throughput-maximized selection user, solving the pre-coding matrix of interference, and by calculating each user The singular value of equivalent channel matrix obtains in the middle of the process of user throughput, employs substantial amounts of singular value decomposition (SVD) step Suddenly, cause its algorithm complex the highest, it is difficult to apply in the middle of real system.3), most users selection scheme only accounts for The optimization problem of the sequence of user selection standard with system goodput as representative, and the user to different service types Qos requirement do not make a distinction.For real time business, its speed is more than the corresponding rate requirement upper limit for real-time industry The lifting of business quality is nonsensical, and this fractional rate is also invalid handling capacity, can cause the money distributing to non-real-time service simultaneously Source is less.

Summary of the invention

The technical problem to be solved is to provide and a kind of uses brand-new design framework method, it is possible to is effectively improved and is The MU-MIMO system true environment low complex degree user choosing method of system effective throughput.

The present invention is to solve above-mentioned technical problem by the following technical solutions: the present invention devises a kind of MU-MIMO system System true environment low complex degree user choosing method, for having the base station of MU-MINO system, carries out user's selection；Described MU- Mimo system true environment low complex degree user choosing method comprises the steps:

Step 001. initializes and selects family set S is empty set, and initialization alternative user set K includes base station MU- Active user in MINO system down link and non real time user, and randomly generate in the most corresponding alternative user set K The channel matrix of each user, meanwhile, initializing set Q to be selected is empty set, and parameter m=1, subsequently into step 002；

Step 002. is respectively directed to each user in alternative user set K, and the channel matrix calculating user is conjugated with it The determinant of the product matrix of matrix, and obtain the determinant corresponding to this determinant, and then obtain in alternative user set K The determinant of each user, then by alternative user set K, the user corresponding to maximum determinant value moves into and has selected family Gather in S, and calculate the kernel of this user, in alternative user set K, delete this user, subsequently into step 003 simultaneously；

Step 003. judges to select in family set S whether there is a user, has selected in family set S in addition to it it The combined channel rank of matrix of he all users, more than the antenna number of base station, is, user selects to terminate；Otherwise enter step 004；

After step 004. assumes that the m-th user in alternative user set K replicates immigration has selected family set S, to Select each user in family set S to carry out block diagonalization process, and calculate this and be newly added user pre-selecting family set S Encoder matrix, further according to the pre-coding matrix of this user, calculates the equivalent channel square of this user in conjunction with the channel matrix of this user Battle array；Equivalent channel matrix and the product matrix determinant of its conjugate matrices then according to this user, it is thus achieved that the speed of this user Low complex degree token state；Subsequently into step 005；

Step 005. continues assuming that the m-th user in alternative user set K replicates immigration has selected family set S's On the basis of, continue to calculate and selected in family set S in addition to this user, the equivalent channel matrix of other each users, and according to The equivalent channel matrix of this each user, and the transition matrix of this each user, calculate the most corresponding speed of this each user The low complex degree token state of rate variable quantity, the low complex degree then according to the most corresponding speed variable quantity of this each user characterizes Amount, updates and has selected the speed low complex degree token state of active user in family set S, subsequently into step 006；

Step 006. continues assuming that the m-th user in alternative user set K replicates immigration has selected family set S's On the basis of, it may be judged whether select the speed low complex degree token state of all active users in family set S to be both greater than it and preset speed Rate low complex degree token state lower limit, is the m-th user in alternative user set K to be copied in set Q to be selected, and enter Step 007；Otherwise abandon replicating m-th user in alternative user set K immigration and select family set S's it is assumed that and enter Step 007；

Step 007. has judged whether for the traversal of all users in alternative user set K, is to enter step 008；Otherwise traverse user sequence number m adds 1, and gives m by this result, is then back to step 004；

Step 008. is chosen a user's immigration making user choose benchmark maximum from set Q to be selected and has been selected family to gather In S, in alternative user set K, delete this user simultaneously by alternative user set K deletes this user simultaneously, and empty to be selected Set Q, subsequently into step 009；

Step 009. is newly added the channel matrix of user according to selecting in family set S, and has selected family to gather S Central Plains There is the pre-coding matrix of each user, calculate and selected the transition matrix of each user original in family set S, further according to selecting The transition matrix of each user original in family set S, updates and has selected the pre-coding matrix of each user corresponding in family set S, It is then back to step 003.

As a preferred technical solution of the present invention: also include that step 010 is as follows, in described step 003, user After selection terminates, enter step 010；

Step 010., according to selecting the channel matrix of each user in family set S, calculates to obtain and has selected in family set S The pre-coding matrix of each user, and utilize block diagonalization method to eliminate the interference selected in family set S between each user.

As a preferred technical solution of the present invention: in described step 010, for any one in alternative user set K Individual user j, passes throughEliminate other users interference, for making pre-coding matrix V_jThere is untrivialo solution, then the side of being required to meet The number of journey is less than the number of variable, it may be assumed that

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<M,\&ForAll;j=1,2,...,\left|S\right|---\left(4\right)$

Therefore for any user of access base station, only other user's combined channel ranks of matrix are less than base station and send out Penetrate summation M of antenna number, pre-coding matrix V could be there is_jEnsureing that each user is not disturbed by other users, this is also true ring To the restriction of user capacity | S | selecting family set S when using block diagonalization technology under border.

As a preferred technical solution of the present invention: in described step 004 to step 006, it is assumed that by alternative user collection A user in conjunction K replicates immigration and has selected in family set S, and in step 008, chooses one and make from set Q to be selected User chooses the maximum user's immigration of benchmark and has selected in family set S, and analysis subscriber channel is respectively at rich scattering and dissipates with non-lipid When penetrating environment, family set S has been selected to be newly added user to being serviced the equivalent channel matrix dimension of user and the impact of order, its In for the pre-coding matrix V of any user j in set S_jDimension beUse n_j ^(|S|)Represent When being | S | as selecting family set S user capacity, user j will not be produced the spatial degrees of freedom number of inter-user interference Mesh, then in richness scattering and low scattering the true environment deposited, n_j ^(|S|)Expression formula be:

${n_j}^{\left(\right|S\left|\right)}=M-{{\hat{L}}_j}^{\left(\right|S\left|\right)}\&GreaterEqual;M-\underset{k=1,k\&NotEqual;j}{\overset{\left|S\right|}{\&Sigma;}}{N}_k---\left(5\right)$

The equivalent channel matrix of user j isBy above to pre-coding matrix V_jThe analysis of dimension understands,ThenOrderAssume in the process carrying out user's selection algorithm In, the number of users that time a certain, etching system services the most simultaneously is | S |, orderRepresent and selected in family set S The combined channel matrix of all users, then Ne_SRepresent combined channel matrix H e_SOrder, Ne_SWithBetween there is relation: Specifically carry out value as follows；

It is derived from

As a preferred technical solution of the present invention: in described step 004 to step 006, the speed of described user is low Complexity token state, obtains this sign by the method utilizing iterative recursive, it is assumed that number of users that may be served is | S |, is simultaneously System general power is P₀Base station MU-MIMO system in, on each transmit power averaging distribution, then can be by the number of user j According to speedIt is expressed as:

$\begin{array}{c}{R}_j^{\left(\right|S\left|\right)}\&ap;{\log }_2{\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)}^{min(N_j,{n_j}^{\left(\right|S\left|\right)})}+{\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\\ =min(N_j,{n_j}^{\left(\right|S\left|\right)}){\log }_2\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right){\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\end{array}---\left(19\right)$

Wherein σ²Represent white Gaussian noise power, Represent corresponding to selecting in family set S User j'sAll nonzero eigenvalues long-pending；P₀Represent that power is always launched in base station；Represent and select User gathers the equivalent channel matrix of user j and the product matrix of its conjugate matrices in S,Represent and selected family collection Close the equivalent channel matrix of any user j in SOrderAnd then obtainValue is incorporated as along with new user's:

User j during (| S |+1) secondary iteration is gone to disturb pre-coding matrix V_j ^(|S|+1), can be by the side of iterative recursive Method obtains this value:

V_j ^(|S|+1)=V_j ^(|S|)G_j ^(|S|+1) (21)

Product angle concept thus according to subspace can obtainWithBetween relational expression be:

In formula, θ_lRepresentation spaceWithBetween l to base vector e_lAnd a_lBetween basic angle. Space can be defined asAnd spaceBetween product angle.

As a preferred technical solution of the present invention: in described step 008, from set Q to be selected, choose a use Family is chosen the maximum user of benchmark and is moved into and selected in family set S, delete in alternative user set K simultaneously this user simultaneously by Alternative user set K deletes this user, and empties set Q to be selected, wherein, be respectively directed to each user in set Q to be selected Q, it is thus achieved that the value of equation below corresponding to each user:And select Take the user wherein corresponding to maximum, i.e. on the basis of maximum user, move it into and select in family set S, simultaneously standby Select the while that set K in family deleting this user by alternative user set K deletes this user, and empty set Q to be selected；Wherein, P_avgRepresent the average emitted power on every, base station transmitting antenna, i.e.

MU-MIMO system true environment low complex degree user choosing method of the present invention uses above technical scheme with existing There is technology to compare, have following technical effect that MU-MIMO system true environment low complex degree user's selecting party designed by the present invention Method, is analyzed based on real wireless transmission environments (rich scattering and non-lipid scattering all exist), has obtained scattering ring in non-lipid The dynamic capacity upper limit that in border, user selects, and made a concrete analysis of user's equivalent channel matrix dimension and order along with user's selection repeatedly The change that the increase in generation is occurred, and by this change application to user's selection reference；It addition, the present invention is by user's equivalent channel Be multiplied with its conjugate matrices nonzero eigenvalue of the matrix obtained of matrix is long-pending, i.e. low complex degree token state selects base as user Accurate so that it is to characterize the admissible rate of user to a certain extent, this product value can be obtained by last iterative value recurrence, Reduce the computation complexity of algorithm, simultaneously on the basis of the differentiated service QoS that becomes more meticulous, improve effectively handling up of system Amount.

Accompanying drawing explanation

Fig. 1 is the flow chart of a kind of MU-MIMO system true environment low complex degree user choosing method designed by the present invention；

Fig. 2 is MU-MIMO system down channel model.

Detailed description of the invention

Below in conjunction with Figure of description, the detailed description of the invention of the present invention is described in further detail.

As it is shown in figure 1, a kind of MU-MIMO system true environment low complex degree user choosing method, pin designed by the present invention To having the base station of MU-MINO system, carry out user's selection；In the middle of actual application, step specific as follows:

Step 001. initializes and selects family set S is empty set, and initialization alternative user set K includes base station MU- Active user in MINO system down link and non real time user, and randomly generate in the most corresponding alternative user set K The channel matrix of each user, meanwhile, initializing set Q to be selected is empty set, and parameter m=1, subsequently into step 002.

Step 002. is respectively directed to each user in alternative user set K, and the channel matrix calculating user is conjugated with it The determinant of the product matrix of matrix, and obtain the determinant corresponding to this determinant, and then obtain in alternative user set K The determinant of each user, then by alternative user set K, the user corresponding to maximum determinant value moves into and has selected family Gather in S, and calculate the kernel of this user, in alternative user set K, delete this user, subsequently into step 003 simultaneously.

Step 003. judges to select in family set S whether there is a user, has selected in family set S in addition to it it The combined channel rank of matrix of he all users, more than the antenna number of base station, is, user selects to terminate, and enters step 010； Otherwise enter step 004.

In above-mentioned steps 003, analyze user capacity upper limit when being in rich scattering and non-lipid scattering environments and equivalent channel Situation, orderRepresent and selected in the collection S of family the combined channel square of all users in addition to user j Battle array, andThenIt it is oneDimension matrix.

RightCarry out singular value decomposition to obtain:

Wherein,ForUnitary matrice, its column vector isCharacteristic vector；∑_jFor The diagonal matrix of dimension, the element on diagonal matrix isSingular value；For M × M rank unitary matrice；Correspond to ∑_j InThe characteristic vector of individual singular value, is oneThe matrix of dimension；OrderThat represent is pre-coding matrix T_jIn For eliminating the part of the multi-user interference of user j, it is the kernel of other users, V_jDimension be

For user j, pre-coding matrix T_jCan be by the product gained of two matrixes, i.e. T_j=V_jB_j.We can lead to Cross and makeEliminate other users interference, for making V_jThere is untrivialo solution, be then required to meet the number of equation less than variable Number, it may be assumed that

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<M,\&ForAll;j=1,2,...,\left|S\right|---\left(4\right)$

Therefore for any user of access base station, only other user's combined channel ranks of matrix are less than base station and send out Penetrate summation M of antenna number, pre-coding matrix V could be there is_jEnsureing that each user is not disturbed by other users, this is also true ring Restriction to user capacity | S | when block uses diagonalization technology under border.

Under rich scattering environments, due toSo the upper limit of system user capacity becomes: This is the user capacity restrictive condition that the utilization BD generally existed in the middle of existing research carries out the mimo system of precoding；And low In the environment of scattering, due toSo user capacity now: | S |_{Low scattering}≥|S|_{Rich scattering}.If therefore for The channel being under low-scattering environments processes according to rich scattering environments, then can affect the user capacity upper limit.

Therefore, when considering based on rich scattering environments, | S | is by antenna for base station number M and user effective reception antenna number (n_r=N₁ =N₂==N_|K|) restriction, be a definite valueAnd the user capacity upper limit | the S | under non-lipid scattering environments Need specifically to calculate.

After step 004. assumes that the m-th user in alternative user set K replicates immigration has selected family set S, to Select each user in family set S to carry out block diagonalization process, and calculate this and be newly added user pre-selecting family set S Encoder matrix, further according to the pre-coding matrix of this user, calculates the equivalent channel square of this user in conjunction with the channel matrix of this user Battle array；Equivalent channel matrix and the product matrix determinant of its conjugate matrices then according to this user, it is thus achieved that the speed of this user Low complex degree token state；Subsequently into step 005.

In above-mentioned steps 004 and below step 005, it is required for calculating the equivalent channel matrix of user, for set S For middle user j, along with the addition of user m, the equivalent channel matrix of the user j in S in set KOrder can change, Thus have influence on its data rate R_j.For replicating the S in the user m in K to set S, calculate each user in S etc. The method of effect channel matrix (step 004 and 005) is all intended to each user in set S is carried out block diagonalization process, and rightMatrix dimensionality be analyzed, and obtain the change condition of its order, and provide user rate R on this basis_j。

Analyzed from step 003, V_jDimension beUse n_j ^(|S|)RepresentCan be by it Regard as when access customer number is | S |, user j will not be produced the spatial degrees of freedom number of inter-user interference.Then dissipate in richness Penetrate and in low scattering the true environment deposited, n_j ^(|S|)Expression formula be:

${n_j}^{\left(\right|S\left|\right)}=M-{{\hat{L}}_j}^{\left(\right|S\left|\right)}\&GreaterEqual;M-\underset{k=1,k\&NotEqual;j}{\overset{\left|S\right|}{\&Sigma;}}{N}_k---\left(5\right)$

By finding V_jMakeTherefore user j is at the received signal vector of down channelBelieve with sending Number vectorRelation be represented by:

y_j=H_jT_jx_j+n_j=H_jV_jB_jx_j+n_j (6)

Wherein, the equivalent channel matrix of user j isBy above to V_jThe analysis of matrix dimensionality understands,ThereforeOrderIt is N for its concrete value_jAlso It is n_j ^(|S|), need us situation to be divided to discuss.

Assuming during carrying out user's selection algorithm, the number of users that time a certain, etching system services the most simultaneously is | S |, orderRepresent the combined channel matrix of all users, then Ne in S_SRepresent combined channel matrix H e_SOrder, Ne_SWithBetween there is relation:

1. whenTime, due toTherefore can meet with lower inequality:

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<{\mathrm{Ne}}_S\&le;\underset{k=1}{\overset{\left|S\right|}{\&Sigma;}}{N}_k,\&ForAll;j\&Element;S---\left(7\right)$

Therefore necessarily haveAccording to (4) formula, thenCertainly exist untrivialo solution.It addition, for n_j ^(|S|)Have:

${n_j}^{\left(\right|S\left|\right)}\&GreaterEqual;M-\underset{k=1,k\&NotEqual;j}{\overset{\left|S\right|}{\&Sigma;}}{N}_k\&GreaterEqual;N_j---\left(8\right)$

Therefore can obtain:

${\stackrel{\&OverBar;}{L}}_j^{\left(\right|S\left|\right)}=N_j---\left(9\right)$

Now to equivalent channel matrixDo singular value decomposition to have:

${{\stackrel{\&OverBar;}{H}}_j}^{\left(\right|S\left|\right)}={\stackrel{\&OverBar;}{U}}_j\left[\begin{array}{cc}{\stackrel{\&OverBar;}{\&Sigma;}}_j& 0\end{array}\right]{\left[\begin{array}{cc}{\stackrel{\&OverBar;}{V}}_j^{\left(1\right)}& {\stackrel{\&OverBar;}{V}}_j^{\left(0\right)}\end{array}\right]}^H---\left(10\right)$

(10) in formula,Be byNon-zero singular value composition N_j×N_jDimension diagonal matrix；ForA left side unusual Vector,For corresponding toIn N_jThe right singular vector of individual singular value.

2. whenTime, with situation 1. shown in, due toTherefore exist:

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<{\mathrm{Ne}}_S,\&ForAll;j\&Element;S---\left(11\right)$

ThereforeCertainly exist untrivialo solution.Situation 2. under, andOrder cannot be judged as n_j ^(|S|)Or N_j, only Can calculate user j's by concreteValue solvesAnd by n_j ^(|S|)With N_jCompare.

3. as M ＜ Ne_S, andTime, the most necessarily meetThere is untrivialo solution.Due at true ring The channel matrix H of user j under border_jVector withThere may exist dependency, therefore meet following formula:

$N_j+{{\hat{L}}_j}^{\left(\right|S\left|\right)}>{\mathrm{Ne}}_S>M,\&ForAll;j\&Element;S---\left(12\right)$

Therefore n can be obtained by (12) formula_j ^(|S|)With N_jRelational expression be:

n_j ^(|S|)＜ N_j (13)

Therefore:

${\stackrel{\&OverBar;}{L}}_j^{\left(\right|S\left|\right)}={n_j}^{\left(\right|S\left|\right)}---\left(14\right)$

Now to equivalent channel matrixDo singular value decomposition to have:

${{\stackrel{\&OverBar;}{H}}_j}^{\left(\right|S\left|\right)}=\left[\begin{array}{cc}{\stackrel{\&OverBar;}{U}}_j^{\left(1\right)}& {{\stackrel{\&OverBar;}{U}}_j}^{\left(0\right)}\end{array}\right]\left[\begin{array}{c}{\stackrel{\&OverBar;}{\&Sigma;}}_j\\ 0\end{array}\right]{\stackrel{\&OverBar;}{V}}_j^{\left(1\right)H}---\left(15\right)$

In above formula,Be dimension be n_j ^(|S|)×n_j ^(|S|)Diagonal matrix,ForLeft singular vector,For right singular vector.

Can obtain from above analysis,Order be N_jOr n_j ^(|S|)Depend on Ne_S,And the size between M three Contrast, is specifically summarized as follows:

Step 005. continues assuming that the m-th user in alternative user set K replicates immigration has selected family set S's On the basis of, continue to calculate and selected in family set S in addition to this user, the equivalent channel matrix of other each users, and according to The equivalent channel matrix of this each user, and the transition matrix of this each user, calculate the most corresponding speed of this each user The low complex degree token state of rate variable quantity, the low complex degree then according to the most corresponding speed variable quantity of this each user characterizes Amount, updates and has selected the speed low complex degree token state of active user in family set S, subsequently into step 006.

Step 006. continues assuming that the m-th user in alternative user set K replicates immigration has selected family set S's On the basis of, it may be judged whether select the speed low complex degree token state of all active users in family set S to be both greater than it and preset speed Rate low complex degree token state lower limit, is the m-th user in alternative user set K to be copied in set Q to be selected, and enter Step 007；Otherwise abandon replicating m-th user in alternative user set K immigration and select family set S's it is assumed that and enter Step 007.

In above-mentioned steps 004 to step 006, the speed low complex degree token state of described user, by utilizing iterative recursive Method obtain this sign, it is assumed that simultaneously number of users that may be served be | S |, system total power be P₀Base station MU-MIMO system In, power averaging distribution on each transmit, then can be by the data rate of user jIt is expressed as:

$\begin{array}{c}{R}_j^{\left(\right|S\left|\right)}\&ap;{\log }_2{\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)}^{min(N_j,{n_j}^{\left(\right|S\left|\right)})}+{\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\\ =min(N_j,{n_j}^{\left(\right|S\left|\right)}){\log }_2\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right){\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\end{array}---\left(19\right)$

Wherein σ²Represent white Gaussian noise power, Represent corresponding to selecting in family set S User j'sAll nonzero eigenvalues long-pending；P₀Represent that power is always launched in base station；Represent and select User gathers the equivalent channel matrix of user j and the product matrix of its conjugate matrices, min (N in S_j,n_j ^(|S|)) represent and select The equivalent channel matrix of any user j in family set SOrderAnd then obtainValue is incorporated as along with new user's:

User j during (| S |+1) secondary iteration is gone to disturb pre-coding matrix V_j ^(|S|+1), can be by the side of iterative recursive Method obtains this value:

${V_j}^{\left(\right|S|+1)}={V_j}^{\left(\right|S\left|\right)}{G_j}^{\left(\right|S|+1)}---\left(21\right)$

Product angle concept thus according to subspace can obtainWithBetween relational expression be:

In formula, θ_lRepresentation spaceWithBetween l to base vector e_lAnd a_lBetween basic angle. Space can be defined asAnd spaceBetween product angle.It is when user capacity is | S | Low complex degree speed token state.

Additionally by above-mentioned user's j data rateExpression formula, we can be by the number after twice iteration of user j Being analyzed according to speed difference, can obtain the changes in data rate in true environment is:

$\begin{array}{c}{\mathrm{\&Delta;R}}_j^{\left(\right|S|+1)}=R_j^{\left(\right|S\left|\right)}-R_j^{\left(\right|S|+1)}\\ \&ap;{\log }_2{\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)}^{{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S\left|\right)}}-{\log }_2{\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)}^{{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S|+1)}}+{\log }_2\left({\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\right)-{\log }_2\left({\mathrm{\&mu;}}_j^{\left(\right|S\left|\mathrm{+1}\right)}\right)\\ =\&lsqb;{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S\left|\right)}-{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S|+1)}\&rsqb;{\log }_2\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)+{\log }_2\left(\frac{{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}}{{\mathrm{\&mu;}}_j^{\left(\right|S|+1)}}\right)\\ =\&lsqb;{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S\left|\right)}-{\stackrel{\&OverBar;}{L}}_j^{\left(\right|S|+1)}\&rsqb;{\log }_2\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)+{\log }_2\frac{1}{{\cos }^2{\mathrm{\&Phi;}}_j^{\left(\right|S|+1)}}\end{array}---\left(35\right)$

In above formula, due toSoBy analyzing, along with adding of user Enter, the order of the equivalent channel matrix of user jOnly may decline, i.e.Therefore can obtainShould Formula shows, system often accesses a new user, and new user can take a part of space resources of segmenting system, causes previous system The data rate of the user accessed likely can be weakened.

Especially, when mimo channel is in rich scattering environments, (38) formula can be changed into:

Under rich scattering environments, due to the restrictive condition of user capacity, it is impossible to occurFeelings Condition.From (36) formula we, when effective reception antenna number of user each in system is identical, (| S |+1) individual new user Selection only can affectIn expression formula, nowThe low complex degree of speed variable quantity Sign isAnd under non-lipid scattering environments,Expression formula be exactly (35) formula.

Step 007. has judged whether for the traversal of all users in alternative user set K, is to enter step 008；Otherwise add 1 for the value corresponding to m, and give m by this result, be then back to step 004.

Step 008. is chosen a user's immigration making user choose benchmark maximum from set Q to be selected and has been selected family to gather In S, in alternative user set K, delete this user simultaneously by alternative user set K deletes this user simultaneously, and empty to be selected Set Q, subsequently into step 009.

In above-mentioned steps 008, from set Q to be selected, choose a user's immigration making user choose benchmark maximum select In family set S, in alternative user set K, delete this user simultaneously by alternative user set K deletes this user simultaneously, and clearly Empty set Q to be selected, wherein, is respectively directed to each user q in set Q to be selected, it is thus achieved that equation below corresponding to each user Value:And choose wherein user corresponding to maximum, it is The user that benchmark is maximum, moves it into and selects in family set S, delete in alternative user set K simultaneously this user simultaneously by Alternative user set K deletes this user, and empties set Q to be selected；Wherein, P_avgRepresent putting down on every, base station transmitting antenna All launch power, i.e.

Step 009. is newly added the channel matrix of user according to selecting in family set S, and has selected family to gather S Central Plains There is the pre-coding matrix of each user, calculate and selected the transition matrix of each user original in family set S, further according to selecting The transition matrix of each user original in family set S, updates and has selected the pre-coding matrix of each user corresponding in family set S, It is then back to step 003.

Step 010., according to selecting the channel matrix of each user in family set S, calculates to obtain and has selected in family set S The pre-coding matrix of each user, and utilize block diagonalization method to eliminate the interference selected in family set S between each user.

Wherein, in step 010, for any one user j in alternative user set K, pass throughEliminate other User disturbs, for making pre-coding matrix V_jThere is untrivialo solution, be then required to meet the number number less than variable of equation, it may be assumed that

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<M,\&ForAll;j=1,2,...,\left|S\right|---\left(4\right)$

Therefore for any user of access base station, only other user's combined channel ranks of matrix are less than base station and send out Penetrate summation M of antenna number, pre-coding matrix V could be there is_jEnsureing that each user is not disturbed by other users, this is also true ring To the restriction of user capacity | S | selecting family set S when using block diagonalization technology under border.

Under rich scattering environments, due toSo having selected the upper limit of family aggregate user capacity to become: This is the user capacity restrictive condition that the utilization BD generally existed in the middle of existing research carries out the mimo system of precoding；And low In the environment of scattering, due toSo user capacity now: | S |_{Low scattering}≥|S|_{Rich scattering}.If therefore for place Channel under low-scattering environments processes according to rich scattering environments, then can affect and select the family aggregate capacity upper limit.

MU-MIMO system true environment low complex degree user choosing method designed by technique scheme, based on truly Wireless transmission environments (rich scattering and non-lipid scattering all exist) be analyzed, obtained user in non-lipid scattering environments and selected The dynamic capacity upper limit, and made a concrete analysis of user's equivalent channel matrix dimension and order and select the increase of iteration to be sent out along with user Raw change, and by this change application to user's selection reference；It addition, user's equivalent channel matrix is conjugated by the present invention with it The nonzero eigenvalue of the matrix that matrix multiple obtains is long-pending, and i.e. low complex degree token state is as user's selection reference so that it is can be Characterizing the admissible rate of user to a certain extent, this product value can be obtained by last iterative value recurrence, reduces algorithm Computation complexity, simultaneously on the basis of the differentiated service QoS that becomes more meticulous, improve the effective throughput of system.

Above in conjunction with accompanying drawing, embodiments of the present invention are explained in detail, but the present invention is not limited to above-mentioned enforcement Mode, in the ken that those of ordinary skill in the art are possessed, it is also possible on the premise of without departing from present inventive concept Make a variety of changes.

Claims (6)

1. a MU-MIMO system true environment low complex degree user choosing method, for having the base station of MU-MINO system, Carry out user's selection；It is characterized in that, comprise the steps:

Step 001. initializes and selects family set S is empty set, and initialization alternative user set K includes base station MU-MINO Active user in system down link and non real time user, and randomly generate respectively in corresponding alternative user set K each The channel matrix of user, meanwhile, initializing set Q to be selected is empty set, and parameter m=1, subsequently into step 002；

Step 002. is respectively directed to each user in alternative user set K, calculates channel matrix and its conjugate matrices of user The determinant of product matrix, and obtain the determinant corresponding to this determinant, and then obtain in alternative user set K each The determinant of user, then by alternative user set K, the user corresponding to maximum determinant value moves into and has selected family to gather In S, and calculate the kernel of this user, in alternative user set K, delete this user, subsequently into step 003 simultaneously；

Step 003. judges to select in family set S whether there is a user, has selected in family set S other institutes in addition to it Having the combined channel rank of matrix antenna number more than base station of user, be, user selects to terminate；Otherwise enter step 004；

After step 004. assumes that the m-th user in alternative user set K replicates immigration has selected family set S, to selecting Each user in family set S carries out block diagonalization process, and calculates this precoding being newly added the user selecting family set S Matrix, further according to the pre-coding matrix of this user, calculates the equivalent channel matrix of this user in conjunction with the channel matrix of this user；Connect The product matrix determinant of the equivalent channel matrix according to this user and its conjugate matrices, it is thus achieved that the low complexity of speed of this user Degree token state；Subsequently into step 005；

Step 005. continues assuming that the m-th user in alternative user set K replicates immigration has selected the basis of family set S On, continue to calculate and selected in family set S in addition to this user, the equivalent channel matrix of other each users, and each according to this The equivalent channel matrix of individual user, and the transition matrix of this each user, calculate the most corresponding speed of this each user and become The low complex degree token state of change amount, then according to the low complex degree token state of the most corresponding speed variable quantity of this each user, Update and selected the speed low complex degree token state of active user in family set S, subsequently into step 006；

Step 006. continues assuming that the m-th user in alternative user set K replicates immigration has selected the basis of family set S On, it may be judged whether select the speed low complex degree token state of all active users in family set S to be both greater than its scheduled rate low Complexity token state lower limit, is the m-th user in alternative user set K to be copied in set Q to be selected, and enter step 007；Otherwise abandon replicating m-th user in alternative user set K immigration and select family set S's it is assumed that and enter step 007；

Step 007. has judged whether for the traversal of all users in alternative user set K, is then to enter step 008；No Then add 1 for the value corresponding to m, and give m by this result, be then back to step 004；

Step 008. is chosen a user's immigration making user choose benchmark maximum from set Q to be selected and has been selected in family set S, In alternative user set K, delete this user simultaneously by alternative user set K deletes this user simultaneously, and empty set to be selected Q, subsequently into step 009；

Step 009. is newly added the channel matrix of user according to selecting in family set S, and selected in family set S original respectively The pre-coding matrix of individual user, calculates and has selected the transition matrix of each user original in family set S, further according to selecting family collection Close the transition matrix of each user original in S, update and selected the pre-coding matrix of each user corresponding in family set S, then Return step 003.

The most according to claim 1, a kind of MU-MIMO system true environment low complex degree user choosing method, its feature exists In: also include that step 010 is as follows, in described step 003, after user selects to terminate, enter step 010；

Step 010., according to selecting the channel matrix of each user in family set S, calculates to obtain and has selected in family set S each The pre-coding matrix of user, and utilize block diagonalization method to eliminate the interference selected in family set S between each user.

The most according to claim 2, a kind of MU-MIMO system true environment low complex degree user choosing method, its feature exists In: in described step 010, for any one user j in alternative user set S, pass throughEliminate other users to do Disturb, for making pre-coding matrix V_jThere is untrivialo solution, be then required to meet the number number less than variable of equation, it may be assumed that

${{\hat{L}}_j}^{\left(\right|S\left|\right)}<M,\&ForAll;j=1,2,...,\left|S\right|---\left(4\right)$

Therefore for any user of access base station, only other user's combined channel ranks of matrix are less than Base Transmitter sky , pre-coding matrix V could be there is in summation M of line number_jEnsureing that each user is not disturbed by other users, this is also under true environment To the restriction of user capacity | S | selecting family set S when using block diagonalization technology.

The most according to claim 3, a kind of MU-MIMO system true environment low complex degree user choosing method, its feature exists In: in described step 004 to step 006, it is assumed that a user in alternative user set K is replicated immigration and has selected family to gather In S, and in step 008, from set Q to be selected, choose a user's immigration making user choose benchmark maximum selected family collection Close in S, when analysis subscriber channel is respectively at rich scattering and non-lipid scattering environments, selected family set S to be newly added user to quilt The equivalent channel matrix dimension of service user and the impact of order.Pre-coding matrix V for any user j in set S_j's Dimension isUse n_j ^(S)RepresentWhen being | S | as selecting family set S user capacity, will not User j is produced the spatial degrees of freedom number of inter-user interference, then in richness scattering and low scattering the true environment deposited, n_j ^(S) Expression formula be:

${n_j}^{\left(\right|S\left|\right)}=M-{{\hat{L}}_j}^{\left(\right|S\left|\right)}\&GreaterEqual;M-\underset{k=1,k\&NotEqual;j}{\overset{\left|S\right|}{\&Sigma;}}{N}_k---\left(5\right)$

The equivalent channel matrix of user j isBy above to pre-coding matrix V_jThe analysis of dimension understands,ThenOrderAssume during carrying out user's selection algorithm, The number of users that time a certain, etching system services the most simultaneously is | S |, orderRepresent and selected institute in family set S There are the combined channel matrix of user, then Ne_SRepresent combined channel matrix H e_SOrder, Ne_SWithBetween there is relation: Specifically carry out value as follows；

It is derived from

The most according to claim 4, a kind of MU-MIMO system true environment low complex degree user choosing method, its feature exists In: in described step 004 to step 006, the speed low complex degree token state of described user, by the method utilizing iterative recursive Obtain this sign, it is assumed that simultaneously number of users that may be served be | S |, system total power be P₀Base station MU-MIMO system in, often Power averaging distribution on individual transmitting antenna, then can be by the data rate of user jIt is expressed as:

$\begin{array}{c}{R}_j^{\left(\right|S\left|\right)}\&ap;{\log }_2{\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)}^{\min (N_j,{n_j}^{\left(\right|S\left|\right)})}+{\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}+\\ =\min (N_j,{n_j}^{\left(\right|S\left|\right)}){\log }_2\left(\frac{P_0}{{\mathrm{\&sigma;}}^{2}M}\right)+{\log }_2{\mathrm{\&mu;}}_j^{\left(\right|S\left|\right)}\end{array}$

Wherein σ²Represent white Gaussian noise power, Represent corresponding to selecting user j in family set S 'sAll nonzero eigenvalues long-pending；P₀Represent that power is always launched in base station；Represent and selected family Gather the equivalent channel matrix of user j in S and the product matrix of its conjugate matrices, min (N_j,n_j ^(S)) represent and selected family to gather S The equivalent channel matrix of middle any user jOrderAnd then obtainValue is incorporated as along with new user's:

User j during (| S |+1) secondary iteration is gone to disturb pre-coding matrix V_j ^(|S|+1), can be obtained by the method for iterative recursive To this value:

V_j ^(|S|+1)=V_j ^(|S|)G_j ^(|S|+1) (21)

Product angle concept thus according to subspace can obtainWithBetween relational expression be:

In formula, θ_lRepresentation spaceWithBetween l to base vector e_lAnd a_lBetween basic angle.Can quilt It is defined as spaceAnd spaceBetween product angle.

The most according to claim 5, a kind of MU-MIMO system true environment low complex degree user choosing method, its feature exists In: in described step 008, from set Q to be selected, choose a user's immigration making user choose benchmark maximum selected family collection Close in S, in alternative user set K, delete this user simultaneously, and empty set Q to be selected, wherein, be respectively directed to set Q to be selected In each user q, it is thus achieved that the value of equation below corresponding to each user:And Choose the user wherein corresponding to maximum, i.e. on the basis of maximum user, move it into and select in family set S, exist simultaneously Alternative user set K deletes this user simultaneously by alternative user set K deletes this user, and empty set Q to be selected；Its In, P_avgRepresent the average emitted power on every, base station transmitting antenna, i.e.