CN104219748A - Method for energy saving and user scheduling of large-scale multi-user multiple input multiple output (MIMO) system - Google Patents

Abstract

The invention relates to a method for energy saving and user scheduling of a large-scale multi-user multiple input multiple output (MIMO) system. The method is characterized by accurately calculating required unlink power and downlink power according to a base station end state and a user equipment end state through a base station and user equipment and performing uplink and downlink data transmission and comprising uplink energy-saving scheduling and downlink energy-saving scheduling. Compared with the prior art, the method has the advantage of being low in computation complexity.

Description

A kind of energy-conservation and user scheduling method of large-scale and multiple users mimo system

Technical field

The present invention relates to a kind of user scheduling method of mimo system, especially relate to a kind of energy-conservation and user scheduling method of large-scale and multiple users mimo system.

Background technology

In large-scale and multiple users mimo system, it is a problem demanding prompt solution that the user who how to carry out low complex degree dispatches to realize energy-conservation.Also there is no at present user's scheduling and the power-economizing method for large-scale and multiple users mimo system specially, in large-scale and multiple users mimo system, use conventional user's scheduling and Poewr control method can bring unnecessary executive overhead, cannot realize best efficiency of energy utilization.

Summary of the invention

Object of the present invention is exactly the energy-conservation and user scheduling method that a kind of large-scale and multiple users mimo system is provided in order to overcome the defect that above-mentioned prior art exists.

Object of the present invention can be achieved through the following technical solutions:

A kind of energy-conservation and user scheduling method of large-scale and multiple users mimo system, user's terminal transmitting power and the descending power that the method needs according to base station end state and subscriber equipment end state accurate Calculation by base station and subscriber equipment also carries out transfer of data, specifically comprises up link energy-saving distribution and down link energy-saving distribution.

Described up link energy-saving distribution comprises the following steps:

101) antenna amount and the noise power of base station end notifying user equipment base station end;

102) subscriber equipment end is measured channel gain and is determined the required up signal-to-noise target value reaching of transmission by reverse link;

103) subscriber equipment end calculates user's terminal transmitting power p required in ul transmissions _{uE, k}:

$p_{\mathrm{UE},k}=\frac{{\mathrm{\σ}}_{\mathrm{BS}}^2{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{UL},k}}{M{\mathrm{\σ}}_{h,k}^2}$

Wherein: for the noise power of subscriber equipment base station end, for up signal-to-noise target value, M is the antenna amount of base station end, for channel gain;

104) subscriber equipment end uses the user's terminal transmitting power calculating to carry out ul transmissions.

Described down link energy-saving distribution comprises the following steps:

201) noise power of subscriber equipment end informing base station end user device end;

202) base station end is measured channel gain and is determined the descending signal-to-noise target value that need to reach by reverse link;

203) base station end calculates and supports the needed descending power of subscriber equipment k downlink transmission

${\stackrel{\‾}{p}}_{\mathrm{BS},k}=\frac{{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{DL},k}{\mathrm{\σ}}_{\mathrm{UE},k}^2}{M{\mathrm{\σ}}_{h,k}^2}$

Wherein, for descending signal-to-noise target value, for the noise power of subscriber equipment end, for channel gain, M is the antenna amount of base station end;

204) base station end is to supporting the needed descending power of all any active ues to sue for peace, if itself and the transmitting power that is greater than base station perform step 205), if itself and the transmitting power that is less than or equal to base station perform step 206);

205) base station end selects k subscriber equipment to obtain service according to choice criteria simultaneously;

206) all any active ues are all served.

Described step 205) in the descending power sum of k subscriber equipment selecting be less than the transmitting power of base station.

Described user equipment (UE) only has an antenna.

Described choice criteria comprises that overall rate maximizes and service object number maximizes.

Compared with prior art, the present invention has the following advantages:

1) realized the power saving in large-scale and multiple users mimo system.

2) computation complexity is low.

Brief description of the drawings

Fig. 1 is up power-economizing method flow chart of the present invention;

Fig. 2 is descending power-economizing method flow chart of the present invention;

Fig. 3 is apparatus structure schematic diagram of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.The present embodiment is implemented as prerequisite taking technical solution of the present invention, provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

An energy-conservation and user scheduling method for large-scale and multiple users mimo system, the present invention is up, and what do is user power control, descending what do is that user dispatches, and is all taking energy-conservation as object.

User's terminal transmitting power and the descending power that the method needs according to base station end state and subscriber equipment end state accurate Calculation by base station and subscriber equipment also carries out transfer of data, specifically comprises up link energy-saving distribution and down link energy-saving distribution.

For up link, the antenna amount that represents base station with M, uses h _{uL, k}represent M × 1 vector channel of user k, the signal that base station receives is:

$y_{\mathrm{BS}}=\underset{k=0}{\overset{K-1}{\mathrm{\Σ}}}\sqrt{p_{\mathrm{UE},k}}{h}_{\mathrm{UL},k}{x}_{\mathrm{UL},k}+n_{\mathrm{BS}}$

Wherein x _{uL, k}user's the symbol that carries message, E (| x _{uL, k}| ²)=1, n _bSthe additive white noise that represents base station, variance is

Because preferably adopt coupling Filter Examination method in large-scale and multiple users mimo system,

${\hat{x}}_{\mathrm{UL},k}=\frac{h_{\mathrm{UL},k}^H{y}_{\mathrm{BS}}}{\sqrt{p_{\mathrm{UE},k}}{\left|\right|h_{\mathrm{UL},k}\left|\right|}^2}$

So the upstream sinr of user k is:

${\mathrm{\ρ}}_{\mathrm{UL},k}=\frac{p_{\mathrm{UE},k}{\left|\right|h_{\mathrm{UL},k}\left|\right|}^2}{{\mathrm{\σ}}_{\mathrm{BS}}^2+{\mathrm{\Σ}}_{k^{\′}\≠k}\frac{p_{\mathrm{UE},k^{\′}}{\left|h_{\mathrm{UL},k}^H{h}_{\mathrm{UL},k^{\′}}\right|}^2}{{\left|\right|h_{\mathrm{UL},k}\left|\right|}^2}}.$

Up energy-conservation: when M very large, and when M > > K,

${\left|\right|h_{\mathrm{UL},k}\left|\right|}^2\≈M{\mathrm{\σ}}_{h,k}^2$

According to the law of large numbers, therefore in the time that M is very large,

${\mathrm{\ρ}}_{\mathrm{UL},k}=\frac{p_{\mathrm{UE},k}{\mathrm{\σ}}_{h,k}^2}{\frac{{\mathrm{\σ}}_{\mathrm{BS}}^2}{M}+{\mathrm{\Σ}}_{k^{\′}\≠k}\frac{p_{\mathrm{UE},k^{\′}}{\left|h_{\mathrm{UL},k}^H{h}_{\mathrm{UL},k^{\′}}\right|}^2}{M^2}}$

In the time that M is very large

$\frac{\left|h_{\mathrm{UL}.k}{h}_{\mathrm{UL},k^{\′}}^H\right|}{M}\≈0$

Therefore, if p _{uE, k}constant with respect to M, so along with increase, ρ _{uE, k}→+∞, but SINR also need not be infinitely great.For ensureing the requirement of transmission quality, we can establish p _{uE, k}reduce along with being reduced to of M is linear, that is:

$p_{\mathrm{UE},k}=\frac{c_k}{M}$

Wherein c _ka coefficient irrelevant with M, by above formula substitution ρ _{uE, k}formula, in the time that M is very large, we can obtain:

${\mathrm{\ρ}}_{\mathrm{UL},k}\≈\frac{c_k{\mathrm{\σ}}_{h,k}^2}{{\mathrm{\σ}}_{\mathrm{BS}}^2}.$

The QoS index that will successfully decode and meet user k transmitting data, requirement

Wherein it is the SINR threshold values of user k.For the given SINR threshold values of user k c _kneed to meet:

$c_k\≥\frac{{\mathrm{\σ}}_{\mathrm{BS}}^2{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{UL},k}}{{\mathrm{\σ}}_{h,k}^2}$

For UE power saving and meet transmission requirement, we can establish:

$c_k={\stackrel{\‾}{c}}_k=\frac{{\mathrm{\σ}}_{\mathrm{BS}}^2{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{UL},k}}{{\mathrm{\σ}}_{h,k}^2}$

Wherein known in base station, known at UE, and UE place measure by reverse link, therefore the transmitting power of UE is:

$p_{\mathrm{UE},k}=\frac{c_k}{M}$

Wherein M is known in base station.

Up user's scheduling: according to ρ _{uL, k}expression formula can find out, when the antenna amount of base station is large and when M > > K, the multi-user interference of up link is negligible, therefore can dispatch all any active ues and send data in up link simultaneously.

As shown in Figure 1, up link energy-saving distribution comprises the following steps:

101) antenna amount and the noise power of base station end notifying user equipment base station end;

102) subscriber equipment end is measured channel gain and is determined the required signal-to-noise target value reaching of transmission by reverse link, and this value is determined by user's request, is known quantity;

103) subscriber equipment end calculates user's terminal transmitting power p required in ul transmissions _{uE, k}:

$p_{\mathrm{UE},k}=\frac{{\mathrm{\σ}}_{\mathrm{BS}}^2{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{UL},k}}{M{\mathrm{\σ}}_{h,k}^2}$

Wherein: for the noise power of subscriber equipment base station end, for up signal-to-noise target value, M is the antenna amount of base station end, for channel gain;

104) subscriber equipment end uses the user's terminal transmitting power calculating to carry out ul transmissions.

Use respectively f _{bS, k}and h _{dL, k}represent M × 1 precoding vector and the vector channel corresponding to 1 × M of user data transmission, the signal that user k receives is:

y _UE，k＝h _DL，kf _BS，kx _DL，k+Σ _k′≠kh _DL，kf _BS，k′x _DL，k′+n _UE，k

Wherein x _{dL, k}the symbol that user k carries message, E (| x _{dL, k}| ²)=1 and n _{uE, k}be the additive white noise of UE, variance is

Because in extensive MIMO tdd systems, suggestion is used in conjunction with wave beam and forms precoding, that is:

$f_{\mathrm{BS},k}=\frac{\sqrt{p_{\mathrm{BS},k}}{h}_{\mathrm{DL},k}^H}{\left|\right|h_{\mathrm{DL},k}\left|\right|}$

Be wherein the distribution power of user k data flow, the reception signal of user k is:

$y_{\mathrm{UE},k}=\sqrt{p_{\mathrm{BS},k}}\left|\right|h_{\mathrm{Dl},k}\left|\right|x_{\mathrm{DL},k}+{\mathrm{\Σ}}_{k^{\′}\≠k}\frac{\sqrt{p_{\mathrm{BS},k}}{h}_{\mathrm{DL},k}{h}_{\mathrm{DL},k^{\′}}^H{x}_{\mathrm{DL},k^{\′}}}{\left|\right|h_{\mathrm{DL},k^{\′}}\left|\right|}+n_{\mathrm{UE},k}$

And

$\underset{k=0}{\overset{K-1}{\mathrm{\Σ}}}{p}_{\mathrm{BS},k}=P_{\mathrm{BS}}.$

Therefore, the down link SINR of user k is:

${\mathrm{\ρ}}_{\mathrm{Dl},k}=\frac{1}{\frac{{\mathrm{\σ}}_{\mathrm{UE},k}^2}{{\left|\right|h_{\mathrm{DL},k}\left|\right|}^2{p}_{\mathrm{BS},k}}+{\mathrm{\Σ}}_{k^{\′}\≠k}\frac{{\left|h_{\mathrm{Dl},k}{h}_{\mathrm{DL},k^{\′}}^H\right|}^2}{{\left|\right|h_{\mathrm{Dl},k}\left|\right|}^2{\left|\right|h_{\mathrm{Dl},k^{\′}}\left|\right|}^2}}$

When M is very large and when M > > K:

${\left|\right|h_{\mathrm{Dl},k}\left|\right|}^2\≈M{\mathrm{\σ}}_{h,k}^2$

According to the law of large numbers and reason:

$\frac{\left|h_{\mathrm{Dl},k}{h}_{\mathrm{Dl},k^{\′}}^H\right|}{M}\≈0$

Therefore

${\mathrm{\ρ}}_{\mathrm{DL},k}\≈\frac{M{\mathrm{\σ}}_{h,k}^2{p}_{\mathrm{BS},k}}{{\mathrm{\σ}}_{\mathrm{UE},k}^2}$

In order can successfully to decode and to meet the QoS index of user k the data of transmission, we need to meet following requirement

Wherein ρ _{dL, k}be the SINR threshold values of user k, the distribution power of user k must meet:

$p_{\mathrm{BS},k}\≥\frac{{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{DL},k}{\mathrm{\σ}}_{\mathrm{UE},k}^2}{M{\mathrm{\σ}}_{h,k}^2}$

Use P _{bS, max}the maximum transmission power that represents base station, base station transmitting power is restricted to:

∑p _BS，k≤P _BS，max.

Downlink user is selected and power division: supposing has K ₁individual any active ues, the power demand of user k distributes and can calculate according to formula below:

${\stackrel{\‾}{p}}_{\mathrm{BS},k}=\frac{{\stackrel{\‾}{\mathrm{\ρ}}}_{\mathrm{DL},k}{\mathrm{\σ}}_{\mathrm{UE},k}^2}{M{\mathrm{\σ}}_{h,k}^2}$

Wherein M is datum in base station, arrange in base station, at base station measurement, need UE to represent, if

$\underset{k=0}{\overset{K_1-1}{\mathrm{\Σ}}}{\stackrel{\‾}{p}}_{\mathrm{BS},k}>P_{\mathrm{BS},\max }$

Basis, choice criteria such as overall rate maximization, satisfies condition so:

$\underset{k=0}{\overset{K-1}{\mathrm{\Σ}}}{\stackrel{\‾}{p}}_{\mathrm{BS},k}\≤P_{\mathrm{BS},\max }$

K user can obtain service simultaneously, user k distributes power to be accordingly

Down link is energy-conservation: if having K user and

$\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}{<P}_{\mathrm{BS},\max }$

So each user's distribution power is and and utilize UE to express the transmitting power that can find out base station is less than P _{bS, max}, this represents that base station transmitting power is energy-conservation has realized.

As shown in Figure 2, down link energy-saving distribution comprises the following steps:

201) noise power of subscriber equipment end informing base station end user device end;

202) base station end is measured channel gain and is determined the received signal to noise ratio desired value that need to reach by reverse link;

203) base station end calculates and supports the needed descending power of subscriber equipment k downlink transmission

${\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}=\frac{{\stackrel{\&OverBar;}{\mathrm{\&rho;}}}_{\mathrm{DL},k}{\mathrm{\&sigma;}}_{\mathrm{UE},k}^2}{M{\mathrm{\&sigma;}}_{h,k}^2}$

Wherein: descending signal-to-noise target value, for the noise power of subscriber equipment end, for channel gain, M is the antenna amount of base station end;

204) base station end is to supporting the needed descending power of all any active ues to sue for peace, if itself and the transmitting power that is greater than base station perform step 205), if itself and the transmitting power that is less than or equal to base station perform step 206);

205) base station end selects k subscriber equipment to obtain service according to choice criteria such as overall rate maximizations simultaneously;

206) all any active ues are all served.

Step 205) in the descending power sum of k subscriber equipment selecting be less than the transmitting power of base station.

Below be given in concrete scene, suppose in a time division duplex cellular system, a certain UE roams into base station and is equipped with in a certain community of a large amount of antennas, in access procedure, UE can find that community is in extensive MIMO mode of operation, antenna amount M and base station noise level are sent to UE by community message, and this message also can be sent to all UE in community by broadcast mode simultaneously.

Up link: if UE has multiple antennas, it will adopt the transmission of main characteristic vector and using main characteristic vector as precoding vector.UE estimates channel variance by backward chaining and transmitting power is adjusted to p _{uE, k}:

$p_{\mathrm{UE},k}=\frac{c_k}{M}$

Wherein:

$c_k={\stackrel{\&OverBar;}{c}}_k=\frac{{\mathrm{\&sigma;}}_{\mathrm{BS}}^2{\stackrel{\&OverBar;}{\mathrm{\&rho;}}}_{\mathrm{UL},k}}{{\mathrm{\&sigma;}}_{h,k}^2}$

obtain from base station, require to arrange according to uplink data flow by UE.

Down link: each UE passes through UE specific messages by noise level be sent to base station, base station is according to the required power division of each user's flowmeter

${\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}=\frac{{\stackrel{\&OverBar;}{\mathrm{\&rho;}}}_{\mathrm{DL},k}{\mathrm{\&sigma;}}_{\mathrm{UE},k}^2}{M{\mathrm{\&sigma;}}_{h,k}^2}$

Wherein be included in the UE specific messages of response, by base station, according to transmission quality requirements setting, M is known quantity in base station, and that estimate by reverse link base station.If there is K ₁individual UE and the base station end of enlivening is to supporting K ₁the needed descending power sum of individual any active ues is greater than the transmitting power of base station, basis is choice criteria such as overall rate maximization so, the base station selected K a satisfying condition user (this K user's descending power sum is not more than the transmitting power of base station), by forming K user's data flow carried out to precoding in conjunction with wave beam, for the power of each customer traffic assignment response, and send all precoded stream simultaneously.If there is this K ₁the needed descending power sum of individual any active ues is not more than the transmitting power of base station, and the power division of so each customer traffic is:

$P=\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}\&le;P_{\mathrm{BS},\max }$

Therefore the transmitting power of base station is:

$P=\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}\&le;P_{\mathrm{BS},\max }$

This represents that base station transmitting power is energy-conservation has realized.

Claims (6)

1. the energy-conservation and user scheduling method of a large-scale and multiple users mimo system, it is characterized in that, user's terminal transmitting power and the descending power that the method needs according to base station end state and subscriber equipment end state accurate Calculation by base station and subscriber equipment also carries out transfer of data, specifically comprises up link energy-saving distribution and down link energy-saving distribution.

2. the energy-conservation and user scheduling method of a kind of large-scale and multiple users mimo system according to claim 1, is characterized in that, described up link energy-saving distribution comprises the following steps:

101) antenna amount and the noise power of base station end notifying user equipment base station end;

102) subscriber equipment end is measured channel gain and is determined the required up signal-to-noise target value reaching of transmission by reverse link;

103) subscriber equipment end calculates user's terminal transmitting power p required in ul transmissions _{uE, k}:

$p_{\mathrm{UE},k}=\frac{{\mathrm{\&sigma;}}_{\mathrm{BS}}^2{\stackrel{\&OverBar;}{\mathrm{\&rho;}}}_{\mathrm{UL},k}}{M{\mathrm{\&sigma;}}_{h,k}^2}$

Wherein: for the noise power of subscriber equipment base station end, for up signal-to-noise target value, M is the antenna amount of base station end, for channel gain;

104) subscriber equipment end uses the user's terminal transmitting power calculating to carry out ul transmissions.

3. the energy-conservation and user scheduling method of a kind of large-scale and multiple users mimo system according to claim 1, is characterized in that, described down link energy-saving distribution comprises the following steps:

201) noise power of subscriber equipment end informing base station end user device end;

202) base station end is measured channel gain and is determined the descending signal-to-noise target value that need to reach by reverse link:

203) base station end calculates and supports the needed descending power of subscriber equipment k downlink transmission

${\stackrel{\&OverBar;}{p}}_{\mathrm{BS},k}=\frac{{\stackrel{\&OverBar;}{\mathrm{\&rho;}}}_{\mathrm{DL},k}{\mathrm{\&sigma;}}_{\mathrm{UE},k}^2}{M{\mathrm{\&sigma;}}_{h,k}^2}$

Wherein: for descending signal-to-noise target value, for the noise power of subscriber equipment end, for channel gain, M is the antenna amount of base station end;

204) base station end is to supporting the needed descending power of all any active ues to sue for peace, if itself and the transmitting power that is greater than base station perform step 205), if itself and the transmitting power that is less than or equal to base station perform step 206);

205) base station end selects k subscriber equipment to obtain service according to choice criteria simultaneously;

206) all any active ues are all served.

4. the energy-conservation and user scheduling method of a kind of large-scale and multiple users mimo system according to claim 3, is characterized in that, described step 205) in the descending power sum of k subscriber equipment selecting be less than the transmitting power of base station.

5. the energy-conservation and user scheduling method of a kind of large-scale and multiple users mimo system according to claim 3, is characterized in that, described user equipment (UE) only has an antenna.

6. the energy-conservation and user scheduling method of a kind of large-scale and multiple users mimo system according to claim 3, is characterized in that, described choice criteria comprises that overall rate maximizes and service object number maximizes.