CN102142873B - Method for designing bidirectional-trunk mutual-transmission beamforming on the basis of network coding - Google Patents

Abstract

The invention discloses a method for designing bidirectional-trunk mutual-transmission beamforming on the basis of network coding, comprising the following steps: receiving data sent by a user node by a relay node, and carrying out network coding; setting a beamforming weighted vector to weight a plurality of antennae; coding the data by a plurality of weighted antennae; respectively transmitting data to the user node, wherein the beamforming weighted vector comprises a first unbiased estimator and a second unbiased estimator, and the first unbiased estimator and the second unbiased estimator obtain a channel gain vector between the user node and each antenna of the relay node; according to the first unbiased estimator and the second unbiased estimator, setting a first adaptive weighting parameter and a second adaptive weighting parameter; and according to the first unbiased estimator, the second unbiased estimator, the first adaptive weighting parameter and the second adaptive weighting parameter, setting the beamforming weighted vector. With the method, the first adaptive weighting parameter and the second adaptive weighting parameter are introduced in to design the proper beamforming weighted vector, and the channel gain from the relay node to the user node is improved.

Description

A kind of two-way relaying of coding Network Based passes the beam shaping method for designing mutually

Technical field

The present invention relates to communication technical field, particularly a kind of two-way relaying of coding Network Based passes the beam shaping method for designing mutually.

Background technology

The relaying facilitating communications can be realized collaboration communication fully, thereby improves the performance and the benefit of system, therefore is used as the direction of future communications development.Network code is as emerging technology, and its core concept is on each node in network the information of receiving on each bar channel to be carried out linearity or nonlinear processing, is transmitted to downstream node then.Since network code can nature be applied in the relaying collaboration communication, therefore in radio communication, have increasing application.

In addition, the multi-antenna beam forming technique can improve the performance of system effectively.For example at transmitting terminal a plurality of antennas (as L root antenna) are arranged, receiving terminal probably can have L receiving gain doubly after the application of beam forming technique so.But existing multi-antenna beam forming technique is directly to utilize channel estimation results to carry out the beam shaping design, and the performance of system is not good and channel gain is not obvious.

Summary of the invention

Purpose of the present invention is intended to solve at least one of above-mentioned technological deficiency, and the two-way relaying that propose a kind ofly to adopt method of weighting especially, has a coding Network Based of obvious gain passes the beam shaping method for designing mutually.

For achieving the above object, the two-way relaying that embodiments of the invention propose a kind of coding Network Based passes the beam shaping method for designing mutually, comprises the steps:

Via node receives first data that send from first user node and second data that send from second user node, and wherein, described via node comprises a plurality of antennas,

Described via node carries out network code to described first data and second data and obtains coded data; And

Described via node is provided with the beam shaping weight vectors and utilizes described beam shaping weight vectors that described a plurality of antennas are weighted, by a plurality of antennas after the described weighting described coded data is sent to described first user node and second user node respectively, wherein, the described beam shaping weight vectors that is provided with comprises the steps:

Obtain second unbiased estimator of the channel gain vector between each antenna of first unbiased estimator of the channel gain vector between each antenna of described first user node and described via node and described second user node and described via node; According to described first unbiased estimator and second unbiased estimator first adaptive weighted parameter and the second adaptive weighted parameter are set; According to described first unbiased estimator, described second unbiased estimator, the described first adaptive weighted parameter and the described second adaptive weighted parameter described beam shaping weight vectors is set.

Two-way relaying according to the coding Network Based of the embodiment of the invention passes the beam shaping method for designing mutually, adopt the relaying collaboration communication, enlarge the area of effective coverage of network, the efficient of simultaneously effective raising system, in addition by introducing the first adaptive weighted parameter and the second adaptive weighted parameter, and according to the unbiased estimator of the channel gain vector between user node and the via node, design suitable beam shaping weight vectors and be weighted, thereby improve the channel gain of via node to user node with each antenna to via node.

Aspect that the present invention adds and advantage part in the following description 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 below in conjunction with accompanying drawing, wherein:

Fig. 1 is according to the user node of the embodiment of the invention and the schematic diagram of via node;

Fig. 2 is the flow chart that passes the beam shaping method for designing according to the two-way relaying of the coding Network Based of the embodiment of the invention mutually;

Fig. 3 is the schematic diagram according to transinformation between the user node of the embodiment of the invention and the via node;

Fig. 4 is the flow chart that the beam shaping weight vectors is set according to the embodiment of the invention; And

Fig. 5 is according to method of weighting under the different measuring error condition of the embodiment of the invention and not method of weighting performance comparison.

Embodiment

Describe embodiments of the invention below in detail, the example of described embodiment is shown in the drawings, and wherein identical from start to finish or similar label is represented identical or similar elements or the element with identical or similar functions.Below by the embodiment that is described with reference to the drawings is exemplary, only is used to explain the present invention, and can not be interpreted as limitation of the present invention.

The two-way relaying of describing according to the coding Network Based of the embodiment of the invention below with reference to Fig. 1 to Fig. 5 passes the beam shaping method for designing mutually.As shown in Figure 1, the beam shaping method for designing that the embodiment of the invention provides is used under many antennas situation, list realizes that by via node information passes mutually to user node, wherein list comprises first user node and second user node to user node, because distance is far away or do not have authority communication, therefore carry out mutual communication between two nodes by via node.Wherein, respectively have an antenna on first user node and second user, have a plurality of antennas on the via node.

Pass mutually by each information of taking turns that via node carries out for user node, as shown in Figure 2, pass the beam shaping method for designing mutually, comprise the steps: according to the two-way relaying of the coding Network Based of the embodiment of the invention

S101: via node receives first data that send from first user and second data that send from second user node;

Merotype when as shown in Figure 3, up link and down link all adopt.In first time slot (SLOT 1), first user node is uploaded the first data D1 to via node.In second time slot (SLOT 2), second user node is uploaded the second data D2 to via node.

Because the via node as receiving terminal has many antennas, therefore need carry out the maximum merging than (MRC to the first data D1 and the second data D2 that on first time slot and second time slot, transmits at via node, Maximal-RatioCombining) operation, thus the signal quality of receiving terminal (via node) can be improved.

By detecting the channel gain vector h between each antenna that can obtain first user node and via node ₁, and the vector of the channel gain between each antenna of second user node and via node h ₂Wherein, h ₁=(h ₁₁, h ₁₂... h _1j... h _1L) ^t, h ₂=(h ₂₁, h ₂₂... h _2j... h _2L) ^t, h _1j(j=1 ..., L) the j root antenna of expression via node is to the channel gain of first user node, h _2j(j=1 ..., L) expression via node j root antenna is to the channel gain of second user node, and L is the antenna amount of via node.

S102: via node carries out network code to first data and second data;

As shown in Figure 3, in the 3rd time slot (SLOT 3), via node adopts the xor operation of bit form to carry out network code to the first data D1 and the second data D2, obtains coded data, promptly

S103: via node is provided with the beam shaping weight vectors and antenna is weighted, and coded data is sent to first user node and second user node.

Utilize the detected channel gain of step S101, adjust the mode of weighting parameters by self adaptation and seek suitable beam forming weight vectors.

As shown in Figure 3 and Figure 4, the beam shaping weight vectors being set comprises the steps:

S1031: obtain first unbiased estimator and second unbiased estimator;

Obtain the vectorial h of channel gain between each antenna of first user node and via node by the method for inserting pilot tone ₁First unbiased estimator

And the vector of the channel gain between each antenna of second user node and via node h ₂Second unbiased estimator

Particularly, in the 3rd time slot (SLOT 3), send to the coded data of first user node at via node

In insert pilot tone, obtain the vectorial h of channel gain between each antenna of first user node and via node ₁First unbiased estimator

${\hat{h}}_1={({\hat{h}}_{11},{\hat{h}}_{12},...{\hat{h}}_{1j}...,{\hat{h}}_{1L})}^t,$

Wherein,

Be the j root antenna of via node estimated value, 1≤j≤L to the channel gain of first user node.

Accordingly, send to the coded data of first user node at via node

In insert pilot tone, obtain the vectorial h of channel gain between each antenna of first user node and via node ₂First unbiased estimator

${\hat{h}}_2={({\hat{h}}_{21},{\hat{h}}_{22},...{\hat{h}}_{2j}...,{\hat{h}}_{2L})}^t,$

Wherein,

Be the j root antenna of via node estimated value, 1≤j≤L to the channel gain of second user node.

S1032: the first adaptive weighted parameter and the second adaptive weighted parameter are set;

In an embodiment of the present invention, introduce the first adaptive weighted parameter alpha ₁With the second adaptive weighted parameter alpha ₂, the first adaptive weighted parameter alpha wherein ₁With the second adaptive weighted parameter alpha ₂Theoretical value be:

${\mathrm{\&alpha;}}_1=\frac{E\left({\left|\right|{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000044658890000021.png,HDA0000044658890000031.png"\; state="\{\{state\}\}">h</figure-callout>}}_1\left|\right|}^2\right)}{E\left({\left|\right|{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000044658890000021.png,HDA0000044658890000031.png"\; state="\{\{state\}\}">h</figure-callout>}}_1\left|\right|}^2\right)+{\mathrm{\&delta;}}_1^2},$ ${\mathrm{\&alpha;}}_2=\frac{E\left({\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000044658890000021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2\right)}{E\left({\left|\right|{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000044658890000021.png"\; state="\{\{state\}\}">h</figure-callout>}}_2\left|\right|}^2\right)+{\mathrm{\&delta;}}_2^2},$

Wherein, h ₁It is the channel gain vector between each antenna of first user node and via node; h ₂It is the channel gain vector between each antenna of second user node and via node; δ ₁Be that the first user node channel measurement error criterion is poor,

Be the variance of the first user node channel measurement error, δ ₂Be that the second user node channel measurement error criterion is poor,

It is the variance of the second user node channel measurement error.

Below according to obtaining first unbiased estimator among the step S1032

With second unbiased estimator

The first adaptive weighted parameter alpha is set ₁With the second adaptive weighted parameter alpha ₂

${\mathrm{\&alpha;}}_1=\frac{\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\left|\right|{\hat{h}}_1\left(i\right)\left|\right|}^2\right)/n-{\mathrm{\&delta;}}_1^2}{\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\left|\right|{\hat{h}}_1\left(i\right)\left|\right|}^2\right)/n},$ ${\mathrm{\&alpha;}}_2=\frac{\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\left|\right|{\hat{h}}_2\left(i\right)\left|\right|}^2\right)/n-{\mathrm{\&delta;}}_2^2}{\left(\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\left|\right|{\hat{h}}_2\left(i\right)\left|\right|}^2\right)/n},$

Wherein, i represents that it is that first user node, second user node pass mutually by the i wheel information of via node that current information passes mutually.

The first adaptive weighted parameter alpha ₁With the second adaptive weighted parameter alpha ₂Span be 0＜α ₁≤ 1,0＜α ₂≤ 1.

In one embodiment of the invention, work as α ₁=α ₂=1 o'clock,

I.e. channel gain between each antenna of first user node and via node vector h ₁Equal its estimated value, i.e. first unbiased estimator And the vector of the channel gain between each antenna of second user node and via node h ₂Equal its estimated value, i.e. first unbiased estimator

S1033: the beam shaping weight vectors is set.

In down link, can adopt the beam shaping weight vectors w after the optimization ^*Different antennas is weighted.

$w^{*}=\arg \underset{w}{\max -\min }({\left|{\mathrm{\&alpha;}}_1{w}^t{\hat{h}}_1\right|}^2,{\left|{\mathrm{\&alpha;}}_2{w}^t{\hat{h}}_2\right|}^2),$

Wherein, α ₁, α ₂Be respectively the first adaptive weighted parameter and the second adaptive weighted parameter,

With

Be respectively the channel gain vector estimated value between two users and each antenna of via node, w=(w ₁, w ₂..., w _L) ^tBe the feasible value of beam shaping weight vectors, w ^*The beam shaping weight vectors that finally obtains for the embodiment of the invention, the i.e. optimal solution of beam shaping weight vectors.

Below according to obtaining among step S1031 and the S1032

α ₁And α ₂Suitable beam shaping weight vectors is set, as follows:

${(w*)}^t=\left\{\begin{array}{c}\sqrt{P/c_1}{\hat{h}}_1^H,{\mathrm{\&alpha;}}_2{c}_{12}\&GreaterEqual;{\mathrm{\&alpha;}}_1{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HDA0000044658890000021.png,HDA0000044658890000031.png"\; state="\{\{state\}\}">c</figure-callout>}}_1;\\ \sqrt{P/c_2}{\hat{h}}_2^H,{\mathrm{\&alpha;}}_1{c}_{12}\&GreaterEqual;{\mathrm{\&alpha;}}_2{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HDA0000044658890000021.png"\; state="\{\{state\}\}">c</figure-callout>}}_2;\\ \sqrt{\frac{{\mathrm{\&alpha;}}_2^2(c_1{c}_2-c_{12}^2)\mathrm{<figure-callout\; id="1"\; label="P\; c"\; filenames="HDA0000044658890000021.png,HDA0000044658890000031.png"\; state="\{\{state\}\}">P</figure-callout>}}{c_{}^{}}}{\hat{h}}_1^H\\ +e^{j\&angle;\left({\hat{h}}_1^H{\hat{h}}_2\right)}\sqrt{\frac{{({\mathrm{\&alpha;}}_1{c}_1-{\mathrm{\&alpha;}}_2{c}_{12})}^{2}P}{({\mathrm{\&alpha;}}_1^2{\mathrm{<figure-callout\; id="1"\; label="c"\; filenames="HDA0000044658890000021.png,HDA0000044658890000031.png"\; state="\{\{state\}\}">c</figure-callout>}}_1+{\mathrm{\&alpha;}}_2^2{c}_2-2{\mathrm{\&alpha;}}_1{\mathrm{\&alpha;}}_2{c}_{12})(c_1{c}_2-c_{12}^2)}}({\hat{h}}_2^H-\frac{{\hat{h}}_2^H{\hat{h}}_1}{c_1}{\hat{h}}_1^H),\end{array}\right.$

w ^*Be beam shaping weight vectors, (w ^*) ^tBe w ^*Transposed vector,

α ₁The first adaptive weighted parameter, α ₂Be the second adaptive weighted parameter,

Expression

The conjugate transpose vector,

Expression The conjugate transpose vector, P is a power,

The expression plural number

Argument.

User node carries out aforesaid many wheels information by via node and passes mutually, takes turns the mutual crossing of information at each, according to user node that obtains after the insertion pilot tone and first unbiased estimator of the channel gain vector between each antenna of via node

With second unbiased estimator The adaptive updates first adaptive weighted parameter alpha ₁Be the second adaptive weighted parameter alpha ₂Thereby, obtain epicycle information is passed only beam shaping weight vectors w mutually ^*

Adopt the beam shaping weight vectors w of above-mentioned acquisition ^*A plurality of antennas to via node are weighted, by a plurality of antennas after the weighting with coded data

Be sent to first user node and second user node respectively, thereby the information between first user node and second user node that realizes passes mutually.

Fig. 5 shows method of weighting and the not comparison of method of weighting performance under the different measuring error condition.As shown in Figure 5, at the channel measurement error criterion difference δ of the first different user nodes ₁Channel measurement error criterion difference δ with second user node ₂Adopt system's average behavior of method of weighting all to be better than adopting not system's average behavior of method of weighting basically down.

Two-way relaying according to the coding Network Based of the embodiment of the invention passes the beam shaping method for designing mutually, adopt the relaying collaboration communication, enlarge the area of effective coverage of network, the efficient of simultaneously effective raising system, in addition by introducing the first adaptive weighted parameter and the second adaptive weighted parameter, and according to the unbiased estimator of the channel gain vector between user node and the via node, design suitable beam shaping weight vectors and be weighted, thereby improve the channel gain of via node to user node with each antenna to via node.

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

Although illustrated and described embodiments of the invention, for the ordinary skill in the art, be appreciated that without departing from the principles and spirit of the present invention and can carry out multiple variation, modification, replacement and modification that scope of the present invention is by claims and be equal to and limit to these embodiment.

Claims (6)

1. the two-way relaying of a coding Network Based passes the beam shaping method for designing mutually, it is characterized in that, comprises the steps:

Via node receives first data that send from first user node and second data that send from second user node, and wherein, described via node comprises a plurality of antennas,

Described via node carries out network code to described first data and second data and obtains coded data; And

Described via node is provided with the beam shaping weight vectors and utilizes described beam shaping weight vectors that described a plurality of antennas are weighted, by a plurality of antennas after the described weighting described coded data is sent to described first user node and second user node respectively, wherein

The described beam shaping weight vectors that is provided with comprises the steps:

Obtain second unbiased estimator of the channel gain between each antenna of first unbiased estimator of the channel gain between each antenna of described first user node and described via node and described second user node and described via node, wherein,

First unbiased estimator of the channel gain vector between described each antenna that obtains described first user node and described via node comprises the steps:

In described via node sends to the coded data of described first user node, insert pilot tone, obtain described first unbiased estimator, wherein,

Be described first unbiased estimator,

Be the j root antenna of described via node estimated value, 1≤j≤L to the channel gain of described first user node;

Second unbiased estimator of the channel gain vector between described each antenna that obtains described second user node and described via node comprises the steps:

In described via node sends to the coded data of described second user node, insert pilot tone, obtain described second unbiased estimator, wherein,

Be described second unbiased estimator,

Be the j root antenna of the described via node estimated value to the channel gain of described second user node, 1≤j≤L, L are the antenna amount of described via node;

According to described first unbiased estimator and second unbiased estimator first adaptive weighted parameter and the second adaptive weighted parameter are set, wherein, described according to described first unbiased estimator with second unbiased estimator is provided with the described first adaptive weighted parameter and the described second adaptive weighted parameter is respectively:

Wherein, described α ₁Be the described first adaptive weighted parameter, α ₂Be the described second adaptive weighted parameter,

Be the variance of the described first user node channel measurement error, Be the variance of the described second user node channel measurement error, i represents that described first user node, described second user node pass mutually by the i wheel information of described via node;

According to described first unbiased estimator, described second unbiased estimator, the described first adaptive weighted parameter and the described second adaptive weighted parameter described beam shaping weight vectors is set.

2. beam shaping method for designing as claimed in claim 1 is characterized in that, described via node carries out the high specific union operation to described first data and described second data.

3. beam shaping method for designing as claimed in claim 1 is characterized in that, described via node carries out network code to described first data and described second data and comprises the steps:

Described via node carries out network code to described first data and the described second The data XOR form.

4. beam shaping method for designing as claimed in claim 1 is characterized in that 0＜α ₁≤ 1,0＜α ₂≤ 1, wherein, α ₁The described first adaptive weighted parameter, α ₂Be the described second adaptive weighted parameter.

5. beam shaping method for designing as claimed in claim 4 is characterized in that, works as α ₁=α ₂=1 o'clock, described first unbiased estimator Equal the channel gain vector h between described first user node and each antenna of described via node ₁, and described second unbiased estimator

Equal the channel gain vector h between described second user node and each antenna of described via node ₂

6. beam shaping method for designing as claimed in claim 1 is characterized in that, described beam shaping weight vectors is:

Wherein, w ^*Be beam shaping weight vectors, (w ^*) ^tBe w ^*Transposed vector,

α ₁Be the described first adaptive weighted parameter, α ₂Be the described second adaptive weighted parameter,

Expression

The conjugate transpose vector,

Expression

The conjugate transpose vector, P is a power,

The expression plural number

Argument.

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