CN101150344B - A downlink multi-stream modulation coding mode selection and power load method - Google Patents

Abstract

A downlink multi-stream modulation and coding method selection and power loading method, comprising the following steps: in the single-user multiple-input multiple-output mode, the data stream with the largest channel quality identifier selects the modulation and coding method of the stream according to its channel quality identifier value, The remaining multiple-input multiple-output data streams use a lower-level modulation and coding method. Channel quality feedback is thereby reduced while maintaining better throughput performance. As an improvement of the method of the present invention, when the signal-to-interference-noise ratio (SINR) of the best stream is greater than the maximum signal-to-interference-noise ratio in the modulation and coding scheme, the base station adopts a method of power loading. The redundant power will be transferred to the remaining streams, so that the throughput of the remaining streams can be improved, while the throughput of the stream with the largest channel quality indicator value remains unchanged.

Description

A kind of downlink multi-stream modulation coding mode is selected and power load method

Technical field

The invention belongs to the multiaerial system technical field, particularly reduce multithread transmission and power load method under the channel quality identification feedback in the multiaerial system.

Background technology

In the downlink transfer of mimo systems, two kinds of patterns of single user and multi-user are arranged.Generally, the channel quality identification of each stream of descending multiple-input, multiple-output all can be fed back to the base station end.But under multi-user mode, each user may only feed back a channel quality identification on the stream.Because the restriction of user feedback signaling capacity, it is particularly important that the expense of channel quality identification feedback signaling seems.Improvement projects more of today, its purpose all are in order to reduce the signaling consumption of descending transmission channel quality identification feedback.

Samsung proposed a kind of dynamic translation scheme that is used in downlink multi-stream transmission (Samsung, R1-061323, " Dynamic Selection of Single and Multi-User MIMO; " 3GPP TSG RAN WG1 Meeting #45, Shanghai, China, 8-12May, 2006. Samsungs, R1-061323, " the Dynamic Selection scheme of single user and multi-user MIMO system; " 3GPP TSG RAN WG1 #45 meeting, Shanghai, China, 8-12 day in May, 2006.).Under single user and multi-user mode, each user is the channel quality identification on stream of base station feedback only.When a user was dispatched in the base station under single user mode, it selected the foundation of modulation coding mode as all stream with the channel quality identification on the stream of channel quality identification maximum.But this modulation coding mode system of selection only is fit to the stream of channel quality identification maximum, and the performance loss of other streams need remedy by mixed automatic retransmission request (HARQ).

Under the environment of every flow rate control (PSRC),, can make the signaling consumption of channel-quality feedback very big like this if single user's mimo systems can carry out channel quality identification usually and estimate on each stream.If multi-user MIMO system, each user can only feed back a channel quality identification on the stream and give the base station.Samsung is at the big shortcoming of feedback signaling expense, and the method that has proposed dynamic translation between single user and the multi-user reduces expense.

Under multi-user 2X2 multiple-input, multiple-output situation, the example of channel-quality feedback and scheduling as shown in Figure 1 in the Samsung scheme.User side comes the calculating channel quality with linear minimum mean-squared error (LMMSE), and in two antennas of base station feedback (stream) a maximum channel quality identification value CQI=max (CQI1, CQI2) and the identification information of this antenna (stream).The base station can be according to the corresponding modulation coding mode of channel quality identification value of maximum then, and data dispatching is given this user on selected antenna.Similarly, in identical running time-frequency resource, another one user is to good channel quality identification on other antennas that can be used to transmit of base station feedback.

Under single user 2X2 multiple-input, multiple-output situation, the example of channel quality identification feedback and scheduling as shown in Figure 2 in the Samsung scheme.User side uses linear minimum mean-squared error (LMMSE) calculating channel quality equally, maximum channel quality identification value in two antennas of base station feedback (stream) then, promptly CQI=max (CQI1, CQI2).In single user's multiple-input, multiple-output, base station decision dispatched users, and on all antennas on this user, select same modulation coding mode to transmit.In fact a channel quality identification feedback only is applicable to an antenna (stream), the selection that can cause the modulation coding mode of lower stream of channel quality identification value or antenna so is not very accurate, in this case, can remedy some performance losss with mixed automatic retransmission request (HARQ).

Summary of the invention

The object of the present invention is to provide a kind of downlink multi-stream modulation coding mode to select and power load method, to reduce the channel quality identification feedback.

For reaching above-mentioned purpose, the present invention adopts following technical scheme: a kind of downlink multi-stream modulation coding mode is selected and power load method, be used for single user's downlink multi-stream mimo systems, the steps include: under single user's MIMO mode, the data flow of channel quality identification maximum is selected the modulation coding mode of this stream according to its channel quality identification value, and remaining multiple-input, multiple-output data flow is selected the modulation coding mode of low one-level for use; The user feeds back to the base station with the channel quality identification of the maximum in all streams.Thereby reduced channel-quality feedback, kept throughput performance preferably simultaneously.

As a kind of improvement of the inventive method, at the Signal Interference and Noise Ratio (SINR) of best stream in greater than modulation coding mode during maximum Signal Interference and Noise Ratio, the method that the base station adopts power to load.Redundant power will be transferred to remaining stream, can improve the throughput of residual stream like this, and the throughput on the stream of channel quality identification value maximum still remains unchanged simultaneously.

A kind of downlink multi-stream modulation coding mode is selected and power load method, be used for multiuser downstream multithread mimo systems, a user reports a channel quality identification to the base station, and goes up the foundation that all data flow are selected modulation coding mode with this value as this user.If the fluxion that user is assigned with is greater than 1, the stream of channel quality identification maximum is selected modulation coding mode according to its channel quality identification value, remaining multiple-input, multiple-output stream is selected the modulation coding mode of low one-level for use, and the user feeds back to the base station with the channel quality identification of the maximum in all streams.If the fluxion of user's distribution equals 1, then report a channel quality identification to the base station, and select the foundation of modulation coding mode with this value as this customer traffic by this user.

Description of drawings

Fig. 1 is for having now at multi-user's multiple-input, multiple-output lower channel quality identification feedback and dispatching method;

Fig. 2 is for having now at single user situation lower channel quality identification feedback and dispatching method;

Fig. 3 is the curve of energy per bit noise ratio (Eb/N0) and Block Error Rate (BLER) under the different modulation coding mode;

Fig. 4 is under the 2X2 system, the comparison of the throughput of various schemes;

Fig. 5 is under the 4X4 system, the comparison of the throughput of various schemes.

Embodiment

A kind of downlink multi-stream modulation coding mode is selected and power load method, may further comprise the steps:

When being used for single user's downlink multi-stream mimo systems, the steps include: under single user's MIMO mode, the data flow of channel quality identification maximum is selected the modulation coding mode of this stream according to its channel quality identification value, and remaining multiple-input, multiple-output data flow is selected the modulation coding mode of low one-level for use.Thereby reduced channel-quality feedback, kept throughput performance preferably simultaneously.

Wherein, at the Signal Interference and Noise Ratio (SINR) of best stream in greater than modulation coding mode during maximum Signal Interference and Noise Ratio, the method that the base station adopts power to load.Redundant power will be transferred to remaining stream, can improve the throughput of residual stream like this, and the throughput on the stream of channel quality identification value maximum still remains unchanged simultaneously.

When being used for multiuser downstream multithread mimo systems, a user reports a channel quality identification to the base station, and goes up the foundation that all data flow are selected modulation coding mode with this value as this user.If the fluxion that user is assigned with is greater than 1, the stream of channel quality identification maximum is selected modulation coding mode according to its channel quality identification value, and remaining multiple-input, multiple-output stream is selected the modulation coding mode of low one-level for use.If the fluxion of user's distribution equals 1, then report a channel quality identification to the base station, and select the foundation of modulation coding mode with this value as this customer traffic by this user.

Suppose that stream 1 is the stream of channel quality identification maximum, and the base station receives its channel quality identification value.P ₁Be the transmitting power on the stream 1, H ₁It is the fading channel matrix on the stream 1.P ₂Be the transmitting power on the stream 2, H ₂It is the fading channel matrix on the stream 2.σ ²It is noise power.In addition, Signal Interference and Noise Ratio (SINR) _IBe the Signal Interference and Noise Ratio of the stream of channel quality identification maximum, Signal Interference and Noise Ratio (SINR) _TargetIt is the Signal Interference and Noise Ratio that highest level modulation coding mode limited on the stream 1.

Can obtain: $\frac{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&CenterDot;H_1}{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2}={\mathrm{<figure-callout\; id="1"\; label="SINR"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">SINR</figure-callout>}}_1\&DoubleRightArrow;{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_1=\frac{{\mathrm{<figure-callout\; id="1"\; label="SINR"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">SINR</figure-callout>}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1};$

If Signal Interference and Noise Ratio (SINR) is found in the base station _IBigger than five-star Signal Interference and Noise Ratio (SINR) in the modulating-coding pattern, Signal Interference and Noise Ratio (SINR) for example _I＞Signal Interference and Noise Ratio (SINR) _Target, following restrictive condition just from flowing 1 transfer power Δ to stream 2, is obeyed in the base station:

$\frac{(P_1-\mathrm{\&Delta;})\&times;H_1}{({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2+\mathrm{\&Delta;})\&times;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2}\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}$

$\&DoubleRightArrow;(P_1-\mathrm{\&Delta;})\&times;{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_1\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}\&times;(({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2+\mathrm{\&Delta;})\&times;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)$

$\&DoubleRightArrow;{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2\&GreaterEqual;\mathrm{\&Delta;}\&times;({\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2)$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2}$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;({\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">H</figure-callout>}}_2+{\mathrm{\&sigma;}}^2)}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="H061B6417X20061019E000021.png,H061B6417X20061019E000022.png"\; state="\{\{state\}\}">P</figure-callout>}}_1\&CenterDot;\frac{{\mathrm{SINR}}_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}}{{\mathrm{SINR}}_1}.$

In the downlink multi-stream mimo systems, suppose that channel model is SCM TU 120.Emulation 5 * 10 ⁴Individual, accept to calculate corresponding Signal Interference and Noise Ratio with linear minimum mean-squared error (LMMSE) on the antenna at each.In addition, the Adaptive Modulation and Coding mode of employing is as follows:

Signal Interference and Noise Ratio=[be lower than 4.2 4.2 5.0 7.2 9.8 and be higher than 9.8];

Adaptive modulation system=[2 2244 4];

Adaptive coding rate=[1/2 1/2 3/4 1/2 2/3 2/3];

In addition, under the different modulation coding modes, the curve of energy per bit noise ratio (Eb/NO) and Block Error Rate (BLER) as shown in Figure 3.QPSK is an orthogonal PSK among Fig. 3, and 16QAM is 16 quadrature amplitude modulation.Throughput calculation on each stream is as follows:

Throughput=Adaptive Modulation pattern * adaptive coding rate * (1-Block Error Rate);

Total throughput is the sum total of the throughput on all streams.

In 2 * 2 (two-way stream) system, the comparison of the throughput of different schemes such as Fig. 4.As can be seen from Figure 4, the throughput of the embodiment of the invention is bigger than the method for prior art-Samsung.When adopting power to load, throughput also has more raising.In addition, be provided with for each stream under its corresponding modulation coding mode situation in the base station, throughput is maximum, and can be considered to the upper bound of this throughput of system.But when adopting power to load, the embodiment of the invention still is better than the situation (not having power to load) of ideal communication channel quality feedback.

From Fig. 4, it can also be seen that, when average signal-to-noise ratio is enough big, 35dB for example, the method for prior art-Samsung is better than the embodiment of the invention.This is because the Signal Interference and Noise Ratio on all streams is also bigger than the Signal Interference and Noise Ratio that highest level modulation coding mode limited possibly.In this situation, the present invention still force the less stream of channel quality identification use than maximum the modulation coding mode of the low one-level of the used modulation coding mode of stream, therefore have the loss of throughput to a certain degree.

Fig. 5 provides some main simulation results under 4 * 4 (4 road stream) system, can obtain the conclusion close with Fig. 4.From Fig. 5, to compare with 2 * 2 systems, throughput has had bigger raising under the environment of 4 * 4 systems, and this conclusion can be explained from information theory easily, because the throughput upper limit and the number of antennas of multiaerial system are linearly proportional.

Claims (3)

1. a downlink multi-stream modulation coding mode is selected and power load method, be used for single user's downlink multi-stream mimo systems, it is characterized in that: the stream of channel quality identification maximum is selected modulation coding mode according to its channel quality identification value, and remaining multiple-input, multiple-output stream is selected the modulation coding mode of low one-level for use; The user feeds back to the base station with the channel quality identification of the maximum in all streams; When the Signal Interference and Noise Ratio of the stream of channel quality identification maximum is gone up the Signal Interference and Noise Ratio that highest level modulation coding mode limited greater than this stream, the method that the base station adopts power to load, redundant power transfer is to remaining stream;

Suppose that stream 1 is the stream of channel quality identification maximum, and the base station receives its channel quality identification value; P ₁Be the transmitting power on the stream 1, H ₁It is the fading channel matrix on the stream 1; P ₂Be the transmitting power on the stream 2, H ₂It is the fading channel matrix on the stream 2; σ ²Be noise power, in addition, Signal Interference and Noise Ratio SINR ₁Be the Signal Interference and Noise Ratio of the stream of channel quality identification maximum, Signal Interference and Noise Ratio SINR _TargetIt is the Signal Interference and Noise Ratio that highest level modulation coding mode limited on the stream 1;

Can obtain: $\frac{P_1\&CenterDot;H_1}{P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2}={\mathrm{SINR}}_1\&DoubleRightArrow;H_1=\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1};$

If Signal Interference and Noise Ratio SINR is found in the base station ₁Than five-star Signal Interference and Noise Ratio SINR in the modulating-coding pattern _TargetWant big, as Signal Interference and Noise Ratio SINR ₁Signal Interference and Noise Ratio SINR _Target, following restrictive condition just from flowing 1 transfer power Δ to stream 2, is obeyed in the base station:

$\frac{(P_1-\mathrm{\&Delta;})\&times;H_1}{(P_2+\mathrm{\&Delta;})\&times;H_2+{\mathrm{\&sigma;}}^2}\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}$

$\&DoubleRightArrow;(P_1-\mathrm{\&Delta;})\&times;H_1\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}\&times;((P_2+\mathrm{\&Delta;})\&times;H_2+{\mathrm{\&sigma;}}^2)$

$\&DoubleRightArrow;P_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2\&GreaterEqual;\mathrm{\&Delta;}\&times;(H_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2)$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{P_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{H_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2}$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;P_1\&CenterDot;\frac{{\mathrm{SINR}}_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}}{{\mathrm{SINR}}_1}..$

2. a downlink multi-stream modulation coding mode is selected and power load method, be used for multiuser downstream multithread mimo systems, it is characterized in that: if the fluxion that user is assigned with is greater than 1, the stream of channel quality identification maximum is selected modulation coding mode according to its channel quality identification value, and remaining multiple-input, multiple-output stream is selected the modulation coding mode of low one-level for use; The user feeds back to the base station with the channel quality identification of the maximum in all streams; When the Signal Interference and Noise Ratio of the stream of channel quality identification maximum is gone up the Signal Interference and Noise Ratio that highest level modulation coding mode limited greater than this stream, the method that the base station adopts power to load, redundant power transfer is to remaining stream;

Suppose that stream 1 is the stream of channel quality identification maximum, and the base station receives its channel quality identification value; P ₁Be the transmitting power on the stream 1, H ₁It is the fading channel matrix on the stream 1; P ₂Be the transmitting power on the stream 2, H ₂It is the fading channel matrix on the stream 2; σ ²It is noise power; In addition, Signal Interference and Noise Ratio SINR ₁Be the Signal Interference and Noise Ratio of the stream of channel quality identification maximum, Signal Interference and Noise Ratio SINR _TargetBe the Signal Interference and Noise Ratio that highest level modulation coding mode limited on the stream 1,

Can obtain: $\frac{P_1\&CenterDot;H_1}{P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2}={\mathrm{SINR}}_1\&DoubleRightArrow;H_1=\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1};$

If Signal Interference and Noise Ratio SINR is found in the base station ₁Than five-star Signal Interference and Noise Ratio SINR in the modulating-coding pattern _TargetWant big, as Signal Interference and Noise Ratio SINR ₁＞Signal Interference and Noise Ratio SINR _Target, following restrictive condition just from flowing 1 transfer power Δ to stream 2, is obeyed in the base station:

$\frac{(P_1-\mathrm{\&Delta;})\&times;H_1}{(P_2+\mathrm{\&Delta;})\&times;H_2+{\mathrm{\&sigma;}}^2}\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}$

$\&DoubleRightArrow;(P_1-\mathrm{\&Delta;})\&times;H_1\&GreaterEqual;{\mathrm{SINR}}_{T\arg \mathrm{et}}\&times;((P_2+\mathrm{\&Delta;})\&times;H_2+{\mathrm{\&sigma;}}^2)$

$\&DoubleRightArrow;P_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2\&GreaterEqual;\mathrm{\&Delta;}\&times;(H_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2)$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{P_1\&CenterDot;H_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{H_1+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2}$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;P_2\&CenterDot;H_2-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;{\mathrm{\&sigma;}}^2}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}+{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;H_2},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)-{\mathrm{SINR}}_{T\arg \mathrm{et}}\&CenterDot;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{\frac{{\mathrm{SINR}}_1\&times;(P_2\&CenterDot;H_2+{\mathrm{\&sigma;}}^2)}{P_1}},$

$\&DoubleRightArrow;\mathrm{\&Delta;}\&le;P_1\&CenterDot;\frac{{\mathrm{SINR}}_1-{\mathrm{SINR}}_{T\arg \mathrm{et}}}{{\mathrm{SINR}}_1}..$

3. a kind of downlink multi-stream modulation coding mode according to claim 2 is selected and power load method, it is characterized in that: if the fluxion of user's distribution equals 1, then report a channel quality identification to the base station, and select the foundation of modulation coding mode with this value as this customer traffic by this user.

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