CN102932043B - Transmission method and device for downlink multi-user multiple input multiple output (MIMO) signal - Google Patents

Abstract

The invention discloses a method for transmitting a downlink multi-user multiple input multiple output (MIMO) signal and a base station. The method comprises the following steps of: dividing remote radio frequency unit (RRU) ports into P/M antenna groups, and storing corresponding relationships between the antenna groups and the ports; judging channels with users, and finding antenna groups corresponding to the channels; receiving pre-coding matrixes fed back from the users, selecting users in different antenna groups, and performing downlink multi-user MIMO transmission; informing the users of the antenna groups and the pre-coding matrixes for downlink data transmission, wherein the pre-coding matrixes are selected from a codebook set with a port number M by the users; and weighting data according to the pre-coding matrixes, outputting the weighted data to the users at antenna ports of the users, and not transmitting the data of the users by using the other ports. Useful signal transmission power is improved, interference is reduced, and indoor cell throughput is improved.

Description

Descending multi-user MIMO signal launching technique and device

Technical field

The invention belongs to wireless mobile communications field, particularly relate to the descending multi-user MIMO signal launching technique and device that are applicable to FDD-LTE indoor distributed system.

Background technology

MIMO (multiple-input and multiple-output) technology is by configuring many antennas at transmitting terminal and receiving terminal, the independence of multipath fading between antenna is utilized to realize the parallel transmission of multiple signals, when not increasing system bandwidth and transmitting power, channel capacity can be improved, also can be used for improving the reliability of channel, reduce the error rate.Thus LTE using MIMO as one of essential technology.

LTE overwhelming majority high-speed data service all occurs in indoor, therefore, how to carry out in-door covering, plays MIMO advantage, promote cell throughout, is the key issue that operator needs when carrying out LTE network and building to solve.

After indoor employing distributed system, consider that the penetration loss between floor and between body of wall is larger, general at about 20-30dB, indoor user is by the signal of its place floor passage of primary recipient, and because indoor user remains static more, channel variation is little, therefore compared with outdoor, utilizes indoor environment to carry out multiuser MIMO and has inherent advantage.

Descending multi-user MIMO code book in current 3GPP standard is identical with Single User MIMO code book, is all permanent mould, and namely each antenna port precoding is only entered horizontal phasing control and do not have the change of amplitude.The feature of the unbalanced power when design of this precoding codebook does not consider that indoor user receives base station multi-antenna port, both wasted power, increased interference again.

Summary of the invention

In view of more than, the present invention proposes descending multi-user MIMO signal launching technique and device.

Descending multi-user MIMO signal launching technique, comprises the following steps:

RRU port is divided into P/M antenna grouping, preserve the corresponding relation of antenna grouping and port, wherein, P is RRU port number, and M is every floor passage number, and P is greater than M;

Judge user place passage, the antenna finding passage corresponding divides into groups;

Receive the pre-coding matrix of user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission;

Notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, and pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix;

Be weighted data according to pre-coding matrix, after user place antenna port is by weighting, data export to user, and all the other ports do not send the data of this user.

Descending multi-user MIMO signal emitter, comprising:

Mapping block, RRU port is divided into P/M antenna grouping, preserve the corresponding relation of antenna grouping and port, wherein, P is RRU port number, and M is every floor passage number, and P is greater than M;

Grouping module, is coupled in mapping block, judges user place passage, and the antenna finding passage corresponding divides into groups;

Select module, be coupled in grouping module, receive the pre-coding matrix of user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission;

Notification module, be coupled in selection module, notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix;

Output module, is weighted data according to pre-coding matrix, and after user place antenna port is by weighting, data export to user, and all the other ports do not send the data of this user.

For existing LTE descending multi-user MIMO signal radiation pattern, the present invention is according to the unbalanced feature of indoor user link, descending multi-user MIMO pairing is carried out to the user being in different passage, when descending multi-user MIMO signal is launched, user's precoding codebook is select in the code book of user place floor passage number at port, to facilitate centralized base-station power at user place channel emission, to user not passage do not launch, thus saving transmitting power, reduce the interference to pairing user, effectively promote indoor cell throughput.

Accompanying drawing explanation

Fig. 1 is mapping relations schematic diagram between FDD-LTE indoor distributed system RRU port of the present invention and antenna grouping.

Fig. 2 is FDD-LTE indoor distributed system descending multi-user MIMO signal launching technique flow chart of the present invention.

Fig. 3 is the structural representation of descending multi-user MIMO signal emitter of the present invention.

Embodiment

In order to solve the defect that prior art exists, the present invention proposes the descending multi-user MIMO signal launching technique and the device that are applicable to FDD-LTE indoor distributed system.For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with drawings and Examples, the present invention is described in further detail.

Fig. 1 is mapping relations schematic diagram between FDD-LTE indoor distributed system RRU of the present invention (Remote RF Unit, remote radio unit (RRU)) port and antenna grouping.Considering that RRU port number P is greater than every floor passage number M, P and is more than or equal to user's reception antenna number N, in order to make full use of MIMO spatial multiplex gains, RRU port being divided into P/M antenna grouping.The floor that each antenna grouping is corresponding certain, the floor that different antenna groupings is corresponding different.The time frequency unit that antenna between grouping adopts the space division multiplexing of multiuser MIMO pattern identical on the downlink channel.

Fig. 2 is FDD-LTE indoor distributed system descending multi-user MIMO signal launching technique flow chart of the present invention.It is as follows that the method comprising the steps of:

In step 201, RRU port is divided into P/M antenna grouping, preserves the corresponding relation of antenna grouping and port.

What P/M obtained is integer.Consider current network indoor distributed system deployment scenario, most probable two kinds are configured to P=4, M=2; P=2, M=1.

In step 202, judge user place passage, the antenna finding passage corresponding divides into groups.

Base station can according to user i different port up channel received power, judges that port that received power is the strongest is as user i place passage, the antenna finding this passage corresponding grouping A ⁽ⁱ⁾for the grouping at this user i place.

for user i is in the received power of port p, i=0,1 ..., Kp=0,1 ....After determining grouping, user can also be added the antenna group list ε at place _a=1,2 ... P/M.

In the pre-coding matrix of step 203, base station receives user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission.Wherein, base station is through the pairing algorithms selection user of prior art.

In step 204, notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, and pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix.

Such as, after base station receives user i precoding matrix feedback, notify that user i will to divide into groups A at antenna by downlink signaling ⁽ⁱ⁾carry out downlink data transmission, pre-coding matrix is user j will to divide into groups A at antenna ^(j)carry out downlink data transmission, pre-coding matrix is wherein A ⁽ⁱ⁾be not equal to A ^(j).

In step 205, be weighted data according to pre-coding matrix, base station data after user place antenna port is by weighting export to user, and all the other ports do not send the data of this user.Such as, the pre-coding matrix that feeds back according to user i at user i place antenna port of base station be weighted data, export to user i, all the other ports do not send the data of user i.The pre-coding matrix that user j place port feeds back according to user j be weighted data, export to user j, all the other ports do not send the data of user j.

To this step, completed the signal emission process of base station to user terminal, when user terminal receives signal, user i and user j can also carry out channel estimating respectively, parses Received signal strength.

For existing LTE descending multi-user MIMO signal radiation pattern, the present invention is according to the unbalanced feature of indoor user link, descending multi-user MIMO pairing is carried out to the user being in different passage, when descending multi-user MIMO signal is launched, user's precoding codebook is select in the code book of user place floor passage number at antenna port number, to facilitate centralized base-station power at user place channel emission, to user not passage do not launch, thus saving transmitting power, reduce the interference to pairing user, effectively promote indoor cell throughput.

Below by specific embodiment, the technical solution of the present invention is further elaborated.But principle involved in the present invention and method are not limited to lower port and antenna number configuration.

Consider the actual conditions of base station, user terminal, indoor distributed system, the embodiment of the present invention will receive 1 terminal, indoor 2 passages for 4 port RRU, 2.Indoor each floor adopts 2 passage compartment systems, and each floor has 2 independent radio frequency passages, namely there are 2 transmit antennas each spaced antenna position.Floor 1 and floor 2 are the first antenna grouping, corresponding RRU port one and RRU port 2, and floor 3 and floor 4 are the second antenna grouping, corresponding RRU port 3 and RRU port 4.

In the present embodiment, RRU port number 4 is greater than every layer of antenna number 2, is also greater than user's reception antenna number 2.When adopting Single User MIMO pattern, the maximum order of single user down channel is 2; When adopting multiuser MIMO pattern, can support that two users carry out the maximum order of down channel is simultaneously the transmission of 2, and will be multiplied power system capacity.

User i is at floor 1, and belong to the first antenna grouping, corresponding RRU port one and RRU port 2, down channel order is 2.User j is at floor 3, and belong to the second antenna grouping, corresponding RRU port 3 and RRU port 4, down channel order is 2.According to the MU-MIMO of 3GPP standard, user i and user j by port be 4 code book in select pre-coding matrix according to channel sequence 2, the pre-coding matrix selected with be 4 × 2 matrixes.Because the code book of current 3GPP standard has constant modulus property, each antenna port amplitude is equal, and just phase weighting is different, to ensure that the power amplifier load being connected to each antenna is identical.Although therefore user i primary recipient comes from the signal of 2 passage antennas of floor 1, receiving the 2 passage antenna powers coming from floor 3 can be very little, and base station still can send user i data S with equal power at port one-port 4 ₁with S ₂.In like manner can send user j data S with equal power at port one-port 4 for user j base station ₃with S ₄.

Suppose user i descending RI=2, PMI=0, wherein, RI (Rank Indicator), channel sequence indicates, PMI (Precoding Matrix Indicator), and pre-coding matrix indicates.User, can by different algorithms after carrying out channel estimating, and minimize error sign ratio etc. as maximized SINR/, select pre-coding matrix, then pre-coding matrix is:

$W_4^{\left(i\right)}=\left(\begin{array}{cc}0.3536& 0.3536\\ 0.3536& -0.3536\\ 0.3536& -0.3536\\ 0.3536& 0.3536\end{array}\right)$

User j descending RI=2, PMI=1, then pre-coding matrix:

$W_4^{\left(j\right)}=\left(\begin{array}{cc}0.3536& -0.3536i\\ 0.3536i& 0.3536\\ -0.3536& -0.3536i\\ -0.3536i& 0.3536\end{array}\right)$

When carrying out MU-MIMO, the signal of Base Transmitter

$S=W_4^{\left(i\right)}\left(\begin{array}{c}{S}_1\\ S_2\end{array}\right)+W_4^{\left(j\right)}\left(\begin{array}{c}{S}_3\\ S_4\end{array}\right)=\left(\begin{array}{cc}0.3536& 0.3536\\ 0.3536& -0.3536\\ 0.3536& -0.3536\\ 0.3536& 0.3536\end{array}\right)\left(\begin{array}{c}{S}_1\\ S_2\end{array}\right)+\left(\begin{array}{cc}0.3536& -0.3536i\\ 0.3536i& 0.3536\\ -0.3536& -0.3536i\\ -0.3536i& 0.3536\end{array}\right)\left(\begin{array}{c}{S}_3\\ S_4\end{array}\right)$

$=\left(\begin{array}{c}0.3536S_1+0.3536S_2+0.3536S_3-0.3536i{S}_4\\ 0.3536S_1-0.3536S_2+0.3536i{S}_3+0.3536S_4\\ 0.3536S_1-0.3536S_2-0.3536S_3-0.3536i{S}_4\\ 0.3536S_1+0.3536S_2-0.3536{\mathrm{iS}}_3+0.3536i{S}_4\end{array}\right)$

As can be seen from base station transmit signals S expression formula, it is user i data S that final each antenna port sends signal ₁, S ₂with user j data S ₃, S ₄carry out constant power superposition.Like this for user i, there is half power dissipation at port 3 and port 4, and interference can be caused to user j.In like manner for user j, there is half power dissipation at port one and port 2, and interference can be caused to user i.

Therefore the present invention proposes, and user i is carry out descending PMI according to the order v of down channel in the code book of M to select feedback at antenna port.In concrete the present embodiment, user i and user j is feed back precoding codebook according to down channel order 2 in the code book of 2 at antenna port number with the precoding codebook selected is 2 × 2 matrixes.

Suppose user i descending RI=2, PMI=1, then the pre-coding matrix of user feedback:

$W_2^{\left(i\right)}=\left(\begin{array}{cc}0.5& 0.5\\ 0.5& -0.5\end{array}\right)$

User j descending RI=2, PMI=2, then the pre-coding matrix of user feedback:

$W_2^{\left(j\right)}=\left(\begin{array}{cc}0.5& 0.5\\ 0.5i& -0.5i\end{array}\right)$

Base station notifies that the downlink data of user i will transmit at antenna port 1 and port 2, and the downlink data of user j will transmit at antenna port 3 and port 4.

The pre-coding matrix that base station is fed back according to user i to downlink data S ₁, S ₂transmit at antenna port 1 and port 2 after weighting, according to the pre-coding matrix that user j feeds back to downlink data S ₃, S ₄transmit at antenna port 3 and port 4 after weighting.

Finally sending signal at antenna for base station port one and port 2 is user i data S ₁with S ₂constant power superposition, sending signal at antenna port 3 and port 4 is user j data S ₃with S ₄constant power superposition.Like this for user i, there is no power dissipation at port 3 and port 4, and minimizing causes interference to user j.In like manner for user j, there is no power dissipation at port one and port 2, and minimizing causes interference to user i.

For P=4, M=2, the pre-coding matrix that base station receives user feedback is 2 × 2, and the emission port of base station is 4, namely be 4 × 2 to the canonical matrix of downlink data weighting, in order to the pre-coding matrix according to user feedback is weighted, other of canonical matrix represented with 0, thus reach and only carry out data transmission at user place passage, other ports do not send the object of this user data.

So, the pre-coding matrix of final base station side is as follows:

When P=2, M=1,

$\left[\begin{array}{c}1\\ 0\end{array}\right]$ $\left[\begin{array}{c}0\\ 1\end{array}\right]$

When P=4, M=2,

$\frac{1}{2}\left[\begin{array}{cc}1& 1\\ 1& -1\\ 0& 0\\ 0& 0\end{array}\right]$ $\frac{1}{2}\left[\begin{array}{cc}1& 1\\ i& -i\\ 0& 0\\ 0& 0\end{array}\right]$ $\frac{1}{\sqrt{2}}\left[\begin{array}{cc}1& 0\\ 0& 1\\ 0& 0\\ 0& 0\end{array}\right]$ $\frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ 1& -1\end{array}\right]$ $\frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ i& -i\end{array}\right]$ $\frac{1}{\sqrt{2}}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 0\\ 0& 1\end{array}\right]$

The precoding codebook being 2 due to antenna port number still has constant modulus property, and therefore when carrying out descending multi-user MIMO, after transmission end of base station weighting on the whole, each antenna port still has constant modulus property.

$S=W_2^{\left(i\right)}\left(\begin{array}{c}{S}_1\\ S_2\end{array}\right)+W_2^{\left(j\right)}\left(\begin{array}{c}{S}_3\\ S_4\end{array}\right)=\left(\begin{array}{cc}0.5& 0.5\\ 0.5& -0.5\\ 0& 0\\ 0& 0\end{array}\right)\left(\begin{array}{c}{S}_1\\ S_2\end{array}\right)+\left(\begin{array}{cc}0& 0\\ 0& 0\\ 0.5& 0.5\\ 0.5i& -0.5i\end{array}\right)\left(\begin{array}{c}{S}_3\\ S_4\end{array}\right)=\left(\begin{array}{c}0.5S_1+0.5S_2\\ 0.5S_1-{0.5S}_2\\ 0.5S_3+{0.5S}_4\\ 0.5i{S}_3-{0.5\mathrm{iS}}_4\end{array}\right)$

User i Received signal strength is:

$y^{\left(i\right)}=H^{\left(i\right)}S+n=\left(\begin{array}{cccc}{h}_{11}^i& h_{12}^i& h_{13}^i& h_{14}^i\\ h_{21}^i& h_{22}^i& h_{23}^i& h_{24}^i\end{array}\right)\left(\begin{array}{c}{S}_{\left(1\right)}\\ S_{\left(2\right)}\\ S_{\left(3\right)}\\ S_{\left(4\right)}\end{array}\right)+n$

User j Received signal strength is:

$y^{\left(j\right)}=H^{\left(j\right)}S+n=\left(\begin{array}{cccc}{h}_{11}^j& h_{12}^j& h_{13}^j& h_{14}^j\\ h_{21}^j& h_{22}^j& h_{23}^j& h_{24}^j\end{array}\right)\left(\begin{array}{c}{S}_{\left(1\right)}\\ S_{\left(2\right)}\\ S_{\left(3\right)}\\ S_{\left(4\right)}\end{array}\right)+n$

In prior art, base station RRU has P (4) individual port, user should be choose pre-coding matrix the codebook set of P (4) from port number, but because floor every in indoor distributed system only has M (2) individual passage, P > M, and floor gap isolation is larger, cause subscriber channel rank of matrix can reduce (most cases is M (2) instead of P (4)), if carry out Single User MIMO transmission, the individual stream of maximum biography M (2), is therefore applicable to doing multiuser MIMO.

In the present invention, carry out multi-user MIMO transmissions, can support that two users divide supplementary biography M (2) individual stream simultaneously, 2M (4) individual stream altogether, user is choose pre-coding matrix the codebook set of M (2) from port number, instead of is the selection feedback of carrying out pre-coding matrix the codebook set of 4 from port number.For each subscriber signal, only launch in user place antenna packet ports, while increase useful signal transmitting power, reduce interference, promote indoor cell throughput.

As shown in Figure 3, the present invention also proposes descending multi-user MIMO signal emitter, comprises mapping block, grouping module, selection module, notification module and output module, and the described device comprising above-mentioned module can be arranged on base station.Wherein:

Mapping block, RRU port is divided into P/M antenna grouping, preserve the corresponding relation of antenna grouping and port, wherein, P is RRU port number, and M is every floor passage number, and P is greater than M.The divisor that P/M obtains is integer.

Grouping module, is coupled in mapping block, judges user place passage, and the antenna finding passage corresponding divides into groups.Wherein, grouping module can according to user's different port up channel received power, judges that passage that port that received power is the strongest is corresponding is as user place passage.Further, user can also be added the antenna group list at place by grouping module, selects module can be in the user of different antennae group list according to the pairing algorithms selection of prior art.

Select module, be coupled in grouping module, receive the pre-coding matrix of user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission.

Notification module, be coupled in selection module, notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix.

Output module, is coupled in notification module, is weighted data according to pre-coding matrix, and after user place antenna port is by weighting, data export to user, and all the other ports do not send the data of this user.

As the conclusion to detailed description, should notice that those skilled in the art will be apparent from can make many changes and amendment to preferred embodiment, and does not depart from principle of the present invention in fact.This change and amendment are included within the scope of the present invention described in appended claims.

Claims (7)

1. descending multi-user MIMO signal launching technique, comprises the following steps:

RRU port is divided into P/M antenna grouping, preserve the corresponding relation of antenna grouping and port, wherein, P is RRU port number, and M is every floor passage number, and P is greater than M;

Base station is according to user's different port up channel received power, and judge that passage that port that received power is the strongest is corresponding is as user place passage, the antenna finding passage corresponding divides into groups, and user is added the antenna group list at place;

Receive the pre-coding matrix of user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission;

Notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, and pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix;

Be weighted data according to pre-coding matrix, after user place antenna port is by weighting, data export to user, and all the other ports do not send the data of this user.

2. descending multi-user MIMO signal launching technique according to claim 1, in the step be weighted data according to pre-coding matrix, the pre-coding matrix of base station side is:

When P=2, M=1,

$\begin{array}{cc}\left[\begin{array}{c}1\\ 0\end{array}\right]& \left[\begin{array}{c}0\\ 1\end{array}\right]\end{array}$

When P=4, M=2,

$\begin{array}{cccccc}\frac{1}{2}\left[\begin{array}{cc}1& 1\\ 1& -1\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}1& 1\\ i& -i\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{\sqrt{2}}\left[\begin{array}{cc}1& 0\\ 0& 1\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ 1& -1\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ i& -i\end{array}\right]& \frac{1}{\sqrt{2}}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 0\\ 0& 1\end{array}\right]\end{array}.$

3. descending multi-user MIMO signal launching technique according to claim 1, selects the user being in different antennae grouping, further comprising the steps of:

The user of different antennae group list is according to pairing algorithms selection.

4. descending multi-user MIMO signal emitter, comprising:

Mapping block, RRU port is divided into P/M antenna grouping, preserve the corresponding relation of antenna grouping and port, wherein, P is RRU port number, and M is every floor passage number, and P is greater than M;

Grouping module, is coupled in mapping block, and according to user's different port up channel received power, judge that passage that port that received power is the strongest is corresponding is as user place passage, the antenna finding passage corresponding divides into groups, and user is added the antenna group list at place;

Select module, be coupled in grouping module, receive the pre-coding matrix of user feedback, select the user being in different antennae grouping, carry out descending multi-user MIMO transmission;

Notification module, be coupled in selection module, notify that user carries out antenna grouping and the pre-coding matrix of downlink data transmission, described pre-coding matrix is user is select the codebook set of M from port number, pre-coding matrix is M × v matrix, and v is subscriber channel rank of matrix;

Output module, is coupled in notification module, is weighted data according to pre-coding matrix, and after user place antenna port is by weighting, data export to user, and all the other ports do not send the data of this user.

5. descending multi-user MIMO signal emitter according to claim 4, output module to the pre-coding matrix that data are weighted is:

When P=2, M=1,

$\begin{array}{cc}\left[\begin{array}{c}1\\ 0\end{array}\right]& \left[\begin{array}{c}0\\ 1\end{array}\right]\end{array}$

When P=4, M=2,

$\begin{array}{cccccc}\frac{1}{2}\left[\begin{array}{cc}1& 1\\ 1& -1\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}1& 1\\ i& -i\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{\sqrt{2}}\left[\begin{array}{cc}1& 0\\ 0& 1\\ 0& 0\\ 0& 0\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ 1& -1\end{array}\right]& \frac{1}{2}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 1\\ i& -i\end{array}\right]& \frac{1}{\sqrt{2}}\left[\begin{array}{cc}0& 0\\ 0& 0\\ 1& 0\\ 0& 1\end{array}\right]\end{array}.$

6. descending multi-user MIMO signal emitter according to claim 4, comprising:

Module is selected to be in the user of different antennae group list according to pairing algorithms selection.

7. descending multi-user MIMO signal emitter according to claim 4 or 5, is arranged on base station.