CN102882569A - Decode-and-forward strategy based multi-antenna relay beam forming method - Google Patents

Abstract

The invention provides a decode-and-forward strategy based multi-antenna relay beam forming method which includes the steps: in the first time slot, obtaining a beam forming vector of a signal source node S, enabling the signal source node S to send signals s1 to a relay node R and a destination node D simultaneously, and enabling the relay node R and the destination node D to receive the signals s1 simultaneously; and in the second time slot, enabling the relay node R to receive and decode the signals s1, recoding information to signals s2 and sending the signals s2 to the destination node D. By the decode-and-forward strategy based multi-antenna relay beam forming method, the design that the beam forming vector of the signal source node S is obtained in the first time slot is provided, so that transmission efficiency is maximized, and channel interrupt probability is minimized; and the relay technology and the multi-antenna beam forming technology are combined together, the optimal beam forming vector is designed, and accordingly transmission efficiency and reliability can be improved, and transmitting power is saved.

Description

A kind of many antenna relays beam-forming method based on the decoding forwarding strategy

Technical field

The invention belongs to the cordless communication network technical field, relate to wireless cooperative relay transmission, particularly a kind of many antenna relays beam-forming method based on the decoding forwarding strategy.

Background technology

Relaying technique can enlarge the coverage of wireless network because of it, improves the rate of information throughput, has been subject to paying close attention to widely.The important means that in the 4G mobile communication technologies such as LTE-Advanced, also will select relaying technique to promote as systematic function.Relaying strategy to be selected is main three major types: the first kind is the relaying strategy that decoding is transmitted, and in this relaying strategy, via node is accurately deciphered, and then forwards; Equations of The Second Kind is amplification forwarding relaying strategy, and in this relaying strategy, via node only amplifies the signal that receives, and then transmits; The 3rd class is to estimate the forward relay strategy, and in this relaying strategy, relaying is done first estimation to the signal that receives, and transmits again.

When relaying technique obtained extensive concern, multi-antenna technology also was the core technology of next generation wireless communication net.Multi-antenna technology can improve the capacity of system on the one hand, also can improve on the other hand system's diversity gain to strengthen reliability.In many antennas skill, both can use the method for Space Time Coding, also can use the method for beam forming.

With relaying technique and the combination of multi-antenna beam forming technique, beam forming vector that can devise optimum improves efficiency of transmission and reliability, saves transmitting power.But, the research that also relaying technique and multi-antenna beam forming technique is not combined at present.

Summary of the invention

The present invention is intended to solve at least the technical problem that exists in the prior art, has proposed to special innovation a kind of many antenna relays beam-forming method based on the decoding forwarding strategy.

In order to realize above-mentioned purpose of the present invention, the invention provides a kind of many antenna relays beam-forming method based on the decoding forwarding strategy, it comprises the steps:

S1: at the first time slot, ask for the beam forming vector of information source node S, and make information source node S to via node R and destination node D while transmitted signal s ₁, via node R and destination node D receive signal s simultaneously ₁

S2: at the second time slot, via node R receives signal s ₁And decoding, again information coding is become signal s ₂And send to destination node D.

The present invention proposes the design of the beam forming vector of information source node when the first time slot, realized that maximise transmission efficiency, channel interruption probability minimize.

In a preferred embodiment of the present invention, the method for asking for the beam forming vector of information source node S is: at information source node S place gain matrix H is carried out singular value decomposition, gain matrix H={H _Ij} _{N * N}Be the channel gain matrix of information source node S to via node R, make H=U Λ V ^H, wherein, U and V are unitary matrice, and Λ is the diagonal matrix of a N * N, and wherein, N is positive integer,

Wherein,, λ ₁〉=λ ₂〉=... 〉=λ _N〉=0 by descending, and the column vector of order matrix V is respectively V=(v ₁, v ₂..., v _N), the beam forming vector of information source node S is:

w _s=Vw=v ₁w ₁+v ₂w ₂++v _Nw _N，

Wherein, w=(w ₁, w ₂..., w _N) ^t, get multiple angle, have:

$\∠w_1=\mathrm{\θ}-\∠h_1^t{v}_1+2k_1\mathrm{\π}$

$\&angle;w_2=\mathrm{\&theta;}-\&angle;h_1^t{v}_2+2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\mathrm{\&pi;}$

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$\&angle;w_N=\mathrm{\&theta;}-\&angle;h_1^t{v}_N+2k_N\mathrm{\&pi;}$

Wherein, θ is any value, k ₁, k ₂..., k _NInteger arbitrarily, h ₁Be the channel gain vector from information source node S to destination node D, order Energy distribution coefficient P _i=| w _i| ², i=1,2 ..., N.

The present invention combines relaying technique and multi-antenna beam forming technique, and the beam forming vector by devise optimum can improve efficiency of transmission and reliability, saves transmitting power.

Additional aspect of the present invention and advantage in the following description part provide, and part will become obviously from the following description, or recognize by practice of the present invention.

Description of drawings

Above-mentioned and/or additional aspect of the present invention and advantage are from obviously and easily understanding becoming the description of embodiment in conjunction with following accompanying drawing, wherein:

Fig. 1 the present invention is based on the time slot map of many antenna relays beam-forming method of decoding forwarding strategy;

Fig. 2 is the system model figure that the present invention is based on many antenna relays beam-forming method utilization of decoding forwarding strategy;

Fig. 3 is the algorithm flow chart of asking for energy distribution coefficient in a kind of preferred implementation of the present invention.

Embodiment

The below describes embodiments of the invention in detail, and the example of described embodiment is shown in the drawings, and wherein identical or similar label represents identical or similar element or the element with identical or similar functions from start to finish.Be exemplary below by the embodiment that is described with reference to the drawings, only be used for explaining the present invention, and can not be interpreted as limitation of the present invention.

The present invention proposes a kind of many antenna relays beam-forming method based on the decoding forwarding strategy, the method is at information source node S and many antennas of via node R configuration, and in the situation of destination node D configuration single antenna, effect is very obvious.Utilize the method, a transmission of taking turns information needs two time slots to finish, and the mode of its transmission comprises the steps: as shown in Figure 1

S1: at the first time slot, ask for the beam forming vector of information source node S, and make information source node S to via node R and destination node D while transmitted signal s ₁, via node R and destination node D receive signal s simultaneously ₁

S2: at the second time slot, via node R receives signal s ₁And decoding, again information coding is become signal s ₂And send to destination node D, in the present embodiment, the coded system of via node R can be in advance and destination node D appoint, can adopt the coded system that generally adopts in this area.

The present invention by information source node S by self with destination node D between direct link, and the help of via node R, the reliable communication between realization and the destination node D.The design of the beam forming vector of information source node S when the first time slot, thus maximise transmission efficiency, channel interruption probability are minimized.

In the system model figure that the many antenna relays beam-forming method that the present invention is based on the decoding forwarding strategy utilizes, as shown in Figure 2, h ₁Be the channel gain vector from information source node S to destination node D, h ₂Be the channel gain vector from the relaying node R to destination node D, H={H _Ij} _{N * N}Be the channel gain matrix of information source node S to via node R.The average power of information source node S is P _s, normalization beam shaping vector is w _s=(w _1s, w _2s..., w _Ns) ^tThe average power of via node R is P _r, normalization beam shaping vector is w _r=(w _1r, w _2r..., w _Nr) ^tThe beam forming vector design of via node R is

And order ${\mathrm{\&gamma;}}_2^{*}={\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2{P}_r.$

In the present embodiment, at the first time slot at first require to win the confidence beam forming vector of source node S, the method for asking for the beam forming vector of information source node S is: at information source node S place gain matrix H is carried out singular value decomposition, gain matrix H={H _Ij} _{N * N}Be the channel gain matrix of information source node S to via node R, make H=U Λ V ^H, wherein, U and V are unitary matrice, and Λ is the diagonal matrix of a N * N, and wherein, N is positive integer,

Wherein, λ ₁〉=λ ₂〉=... 〉=λ _N〉=0 by descending, and the column vector of order matrix V is respectively V=(v ₁, v ₂..., v _N), the beam forming vector of information source node S is:

w _s=Vw=v ₁w ₁+v ₂w ₂++v _Nw _N，

Wherein, w=(w ₁, w ₂..., w _N) ^t, get multiple angle, have:

$\&angle;w_1=\mathrm{\&theta;}-\&angle;h_1^t{v}_1+2k_1\mathrm{\&pi;}$

$\&angle;w_2=\mathrm{\&theta;}-\&angle;h_1^t{v}_2+2{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\mathrm{\&pi;}$

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$\&angle;w_N=\mathrm{\&theta;}-\&angle;h_1^t{v}_N+2k_N\mathrm{\&pi;}$

Wherein, θ is any value, k ₁, k ₂..., k _NInteger arbitrarily, order

Energy distribution coefficient P _i=| w _i| ², i=1,2 ..., N.Obtaining energy distribution coefficient P _iAfter, also namely obtained the beam forming vector.

In order to ask for energy distribution coefficient P _i, given following preparation optimization problem:

${\max }_{P_1,{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">P</figure-callout>}}_2,\&CenterDot;\&CenterDot;\&CenterDot;,P_N}{a}_1\sqrt{P_1}+a_2\sqrt{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}+\&CenterDot;\&CenterDot;\&CenterDot;+a_N\sqrt{P_N}$

s.t. P ₁+P ₂+…+P _N=1

${\mathrm{\&lambda;}}_1^2{P}_1+{\mathrm{\&lambda;}}_2^2{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">P</figure-callout>}}_2+\&CenterDot;\&CenterDot;\&CenterDot;+{\mathrm{\&lambda;}}_N^2{P}_N={\mathrm{\&gamma;}}_R$

Wherein, γ _RBe the numerical value that presupposes in this preparation optimization problem, in computational process, its initial value is value arbitrarily.

The solution of this preparation optimization problem is:

$P_1={\left(\frac{a_1}{2u+2v{\mathrm{\&lambda;}}_1^2}\right)}^2$

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">P</figure-callout>}}_2={\left(\frac{a_2}{2u+2v{\mathrm{\&lambda;}}_2^2}\right)}^2$

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$P_N={\left(\frac{a_n}{2u+2v{\mathrm{\&lambda;}}_N^2}\right)}^2$

Wherein, u and v are real numbers, and satisfy following relation:

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left(\frac{a_i}{2u+2v{\mathrm{\&lambda;}}_i^2}\right)}^2=1$

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{\left(\frac{a_i}{2u+2v{\mathrm{\&lambda;}}_i^2}\right)}^2={\mathrm{\&gamma;}}_R$

Under the condition of the solution of this optimization problem, definition ${\mathrm{\&gamma;}}_1={(a_1\sqrt{P_1}+a_2\sqrt{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">P</figure-callout>}}_2}+\&CenterDot;\&CenterDot;\&CenterDot;+a_N\sqrt{P_N})}^2{P}_s.$

According to above preparation optimization problem, final energy distribution coefficient P _iSolution be:

When $\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2{P}_s+{\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2{P}_r<\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">i</figure-callout>}}^2}{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2}{P}_s$ The time, then energy distribution coefficient is $P=(\frac{a_1^2}{\mathrm{\&Sigma;}{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">i</figure-callout>}}^2},\frac{a_2^2}{\mathrm{\&Sigma;}{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">i</figure-callout>}}^2},\&CenterDot;\&CenterDot;\&CenterDot;,\frac{a_{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">N</figure-callout>}}^2}{\mathrm{\&Sigma;}{a}_i^2});$

When

The time, energy distribution coefficient be P=(1,0 ..., 0);

When not satisfying $\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2{P}_s+{\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2{P}_r<\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">i</figure-callout>}}^2}{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2}{P}_s,$ Do not satisfy yet $a_1^2{P}_s+{\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2{P}_r>{\mathrm{\&lambda;}}_1^2{P}_s$ The time, utilize algorithm calculating energy distribution coefficient shown in Figure 3, step is:

S41: initialization makes x ₁=x _s, x ₂=x _t, wherein, $x_s=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{a}_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">i</figure-callout>}}^2}{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2}{P}_s,$ $x_t={\mathrm{\&lambda;}}_1^2{P}_s;$

S42: the γ in the order preparation optimization problem _R=(x ₁+ x ₂)/2, the calculating correspondence obtains

Wherein ${\mathrm{\&gamma;}}_2^{*}={\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA00002196366200021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2{P}_r;$

S43: judge whether to satisfy

When not satisfying, calculate and finish, utilize method claimed in claim 3 to ask for energy distribution coefficient P _i, when satisfying, enter step S44;

S44: judge whether to satisfy

When satisfying, order

When not satisfying, order

Return step S42.

The present invention combines relaying technique and multi-antenna beam forming technique, and the beam forming vector by devise optimum can improve efficiency of transmission and reliability, saves transmitting power.

In the description of this specification, the description of reference term " embodiment ", " some embodiment ", " example ", " concrete example " or " some examples " etc. means to be contained at least one embodiment of the present invention or the example in conjunction with specific features, structure, material or the characteristics of this embodiment or example description.In this manual, the schematic statement of above-mentioned term not necessarily referred to identical embodiment or example.And the specific features of description, structure, material or characteristics can be with suitable mode combinations in any one or more embodiment or example.

Although illustrated and described embodiments of the invention, those having ordinary skill in the art will appreciate that: can carry out multiple variation, modification, replacement and modification to these embodiment in the situation that does not break away from principle of the present invention and aim, scope of the present invention is limited by claim and equivalent thereof.

Claims (4)

1. the many antenna relays beam-forming method based on the decoding forwarding strategy is characterized in that, comprises the steps:

S1: at the first time slot, ask for the beam forming vector of information source node S, and make information source node S to via node R and destination node D while transmitted signal s ₁, via node R and destination node D receive signal s simultaneously ₁

S2: at the second time slot, via node R receives signal s ₁And decoding, again information coding is become signal s ₂And send to destination node D.

As claimed in claim 1 based on decoding forwarding strategy many antenna relays beam-forming method, it is characterized in that, the described method of asking for the beam forming vector of information source node S is: at information source node S place gain matrix H is carried out singular value decomposition, gain matrix H={H _Ij} _{N * N}Be the channel gain matrix of information source node S to via node R, make H=U Λ V ^H, wherein, U and V are unitary matrice, and Λ is the diagonal matrix of a N * N, and wherein, N is positive integer,

Wherein, λ ₁〉=λ ₂〉=... 〉=λ _N〉=0 by descending, and the column vector of order matrix V is respectively V=(v ₁, v ₂..., v _N), the beam forming vector of information source node S is:

w _s=Vw=v ₁w ₁+v ₂w ₂++v _Nw _N，

Wherein, w=(w ₁, w ₂..., w _N) ^t, get multiple angle, have:

$\&angle;w_1=\mathrm{\&theta;}-\&angle;h_1^t{v}_1+2k_1\mathrm{\&pi;}$

$\&angle;w_2=\mathrm{\&theta;}-\&angle;h_1^t{v}_2+2k_2\mathrm{\&pi;}$

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$\&angle;w_N=\mathrm{\&theta;}-\&angle;h_1^t{v}_N+2k_N\mathrm{\&pi;}$

Wherein, θ is any value, k ₁, k ₂..., k _NInteger arbitrarily, h ₁Be the channel gain vector from information source node S to destination node D, order

Energy distribution coefficient P _i=| w _i| ², i=1,2 ..., N.

3. the many antenna relays beam-forming method based on the decoding forwarding strategy as claimed in claim 2 is characterized in that, asks for described energy distribution coefficient P _i, i=1,2 ..., during N, utilize the preparation optimization problem:

${\max }_{P_1,P_2,\&CenterDot;\&CenterDot;\&CenterDot;,P_N}{a}_1\sqrt{P_1}+a_2\sqrt{P_2}+\&CenterDot;\&CenterDot;\&CenterDot;+a_N\sqrt{P_N}$

s.t. P ₁+P ₂+…+P _N=1

${\mathrm{\&lambda;}}_1^2{P}_1+{\mathrm{\&lambda;}}_2^2{P}_2+\&CenterDot;\&CenterDot;\&CenterDot;+{\mathrm{\&lambda;}}_N^2{P}_N={\mathrm{\&gamma;}}_R$

The solution of described preparation optimization problem is:

$P_1={\left(\frac{a_1}{2u+2v{\mathrm{\&lambda;}}_1^2}\right)}^2$

$P_2={\left(\frac{a_2}{2u+2v{\mathrm{\&lambda;}}_2^2}\right)}^2$

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$P_N={\left(\frac{a_n}{2u+2v{\mathrm{\&lambda;}}_N^2}\right)}^2$

Wherein, u and v are real numbers, and satisfy following relation:

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left(\frac{a_i}{2u+2v{\mathrm{\&lambda;}}_i^2}\right)}^2=1$

$\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{\left(\frac{a_i}{2u+2v{\mathrm{\&lambda;}}_i^2}\right)}^2={\mathrm{\&gamma;}}_R$

Order

Wherein, P _sAverage power for information source node S.

4. as claimed in claim 2 or claim 3 based on many antenna relays beam-forming method of decoding forwarding strategy, it is characterized in that described energy distribution coefficient P _iObtaining value method be:

When

The time, wherein, h ₂That via node R is to the channel gain vector of destination node D, P _rBe the average power of via node R, then energy distribution coefficient is

When

The time, energy distribution coefficient be P=(1,0 ..., 0);

When not satisfying $\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2{P}_s+{\left|\right|h_2\left|\right|}^2{P}_r<\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{a}_i^2}{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2}{P}_s,$ Do not satisfy yet $a_1^2{P}_s+{\left|\right|h_2\left|\right|}^2{P}_r>{\mathrm{\&lambda;}}_1^2{P}_s$ The time, the acquiring method of energy distribution coefficient is:

S41: initialization makes x ₁=x _s, x ₂=x _t, wherein, $x_s=\frac{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_i^2{a}_i^2}{\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{a}_i^2}{P}_s,$ $x_t={\mathrm{\&lambda;}}_1^2{P}_s;$

S42: the γ in the preparation optimization problem _R=(x ₁+ x ₂)/2, the calculating correspondence obtains

Wherein ${\mathrm{\&gamma;}}_2^{*}={\left|\right|h_2\left|\right|}^2{P}_r;$

S43: judge whether to satisfy

When not satisfying, calculate and finish, utilize method claimed in claim 3 to ask for energy distribution coefficient P _i, when satisfying, enter step S44;

S44: judge whether to satisfy

When satisfying, order

When not satisfying, order

Return step S42.

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