CN1956351B - Beam forming method and device for multiple input/output system - Google Patents

Abstract

This invention provides a beam forming method used in a multiple input and output system, in which, the system transmits signals via multiple channels, and the method includes: generating multiple channel estimation results corresponding to the channels, deciding multiple first candidate transmission vectors to select a first transmission vector with the MaxSNR from them based on the channel estimation results, deciding multiple second candidate transmission vectors with the MaxSNR from the second candidate vectors to integrate a firs and a second data flows to generate multiple transmission signals and sending out the signals on multiple antennas.

Description

The wave beam that is applied in the multiple input-output system forms method and apparatus

Technical field

The present invention relates to a kind of beam-forming device and correlation technique, particularly a kind of beam-forming device and correlation technique that is applied to multiple input-output system.

Background technology

(Multiple-Input Multiple-Output, MIMO) main concept of system is in transmission end and receiving terminal many antennas to be set respectively, to come transceive data by the channel between many antennas in multiple input and output.For instance, Fig. 1 is to be the sketch map of an existing multiple input-output system 10.As shown in the figure; Multiple input-output system 10 has a transmission ends 20 and a receiving terminal 30; Transmission ends 20 is provided with three antennas 22,24,26; And also be provided with two antennas 32,34 on the receiving terminal 30, so the data that transmission ends 20 is sent can arrive receiving terminal 30 via 3*2 channel 42,44,46,48,52,54.Suppose that transmission ends 20 is to transmit two data flow D1, D2 simultaneously to receiving terminal 30, then transmission ends 20 is can earlier data flow D1, D2 be multiplied by yield value respectively and be integrated into three transmission signal S1, S2, S3 to send respectively at antenna 22,24,26 then.The producing method that transmits signal S1, S2, S3 is represented by following equation:

S1=D1*V _1,1+ D2*V _1,2Equation (one)

S2=D1*V _2,1+ D2*V _2,2Equation (two)

S3=D1*V _3,1+ D2*V _3,2Equation (three)

Can know three-dimensional vector [V by equation (), (two), (three) _1,1, V _2,1, V _3,1] ^TBe to be used for determination data stream D1 in transmission signal S1, S2, the shared composition of S3, so three-dimensional vector [V _1,1, V _2,1, V _3,1] ^TCan be considered the transmission vector of data flow D1; In like manner, three-dimensional vector [V _1,2, V _2,2, V _3,2] ^TBe to be used for determination data stream D2 in transmission signal S1, S2, the shared composition of S3, so three-dimensional vector [V _1,2, V _2,2, V _3,2] ^TCan be considered the transmission vector of data flow D2.

In order receiving terminal can be separated smoothly transmit data flow D1 and the data flow D2 among signal S1, S2, the S3, prior art is to utilize a singular value decomposition method (Singular Value Decomposition SVD) decides and transmits vector [V _1,1, V _2,1, V _3,1] ^T, [V _1,2, V _2,2, V _3,2] ^T, so that data flow D1 that receiving terminal is received and data flow D2 mutually orthogonal (Orthogonal).Yet, utilize singular value decomposition method to produce and transmit vector [V _1,1, V _2,1, V _3,1] ^T, [V _1,2, V _2,2, V _3,2] ^TMode must carry out a large amount of floating-point operations, therefore can expend quite huge operand.In addition, utilize singular value decomposition method to produce and transmit vector [V _1,1, V _2,1, V _3,1] ^T, [V _1,2, V _2,2, V _3,2] ^TCan't avoid the power division of data flow D1, D2 uneven; Or the uneven problem of the power division between antenna; Because data flow D1, D2 encode together in the transmission end and use same modulation system to produce, so when the phenomenon generation of above-mentioned power division inequality, will reduce the correctness that data flow D1, D2 decode.

Summary of the invention

Therefore, one of the object of the invention is to provide a kind of beam-forming device and correlation technique.

In addition, one of the object of the invention is to provide a kind of beam-forming device and correlation technique to solve the problem of prior art.

According to one embodiment of the invention; It is to disclose a kind of wave beam formation method that is applied to a multiple input-output system; Wherein, this multiple input-output system includes a transmission end and a receiving terminal, and this transmission end and this receiving terminal are to transmit signal via a plurality of channels.This wave beam formation method includes: produce a plurality of channel estimating results that should a plurality of channels at this receiving terminal; Determine a plurality of first candidate's transmission vector; According to these a plurality of channel estimating results, these a plurality of first candidate's transmission vector are chosen one first transmission vector with maximum signal to noise ratio certainly; Determine a plurality of second candidate's transmission vector, and each second candidate's transmission vector is to be orthogonal to this first transmission vector; According to these a plurality of channel estimating results, choose one second transmission vector in these a plurality of second candidate's transmission vector certainly with maximum signal to noise ratio; Integrate one first data flow and one second data flow to produce a plurality of transmission signals according to this first transmission vector and this second transmission vector; And on many antennas of this transmission end, see these a plurality of transmission signals respectively off.

According to one embodiment of the invention; It is to disclose a kind of beam-forming device that is applied to a multiple input-output system; Wherein, this multiple input-output system includes a transmission end and a receiving terminal, and this transmission end and this receiving terminal are to transmit signal via a plurality of channels.This beam-forming device includes: a channel estimator is used for producing to a plurality of channel estimating results that should a plurality of channels; One first transmission vector generation module is coupled to this channel estimator, with deciding a plurality of first candidate's transmission vector, and according to choosing one first transmission vector with maximum signal to noise ratio in oneself these a plurality of first candidate's transmission vector of this a plurality of channel estimating results; One second transmission vector generation module; Be coupled to this channel estimator and this first transmission vector generation module; Use and decide a plurality of second candidate's transmission vector that are orthogonal to this first transmission vector, and in these a plurality of second candidate's transmission vector, choose one second transmission vector with maximum signal to noise ratio according to these a plurality of channel estimating results; One data processing module is coupled to this first transmission vector generation module and this second transmission vector generation module, is used for integrating one first data flow and one second data flow to produce a plurality of transmission signals according to this first transmission vector and this second transmission vector; And many antennas, be coupled to this data processing module, be used for transmitting these a plurality of transmission signals.

Description of drawings

Fig. 1 is the sketch map of an existing multiple input-output system.

Fig. 2 is the operation workflow figure of a preferred embodiment of beam-forming device of the present invention.

Fig. 3 is the functional block diagram of a preferred embodiment of beam-forming device of the present invention.

The reference numeral explanation

10 multiple input-output systems

20 transmission ends

30 receiving terminals

22,24,26,32,34,252,254,256,258 antennas

42,44,46,48,52,54 channels

200 beam-forming devices

202 channel estimators

210,220-transmission vector generation module

212,222-candidate transmission vector generation unit

214,224 signal to noise ratio arithmetic elements

216,226 comparing units

218,228 choose the unit

230 weighted units

240 data processing modules

Embodiment

See also Fig. 2, Fig. 2 is the operation workflow figure for a preferred embodiment of beam-forming device of the present invention (Beam-Forming Device).In the present embodiment, beam-forming device is to be applied to multiple input and output (Multiple-Input Multiple-Output) system, and wherein multiple input-output system is to include a transmission end and a receiving terminal.Be convenient explanation, following operation workflow is that the multiple input-output system of hypothesis is two data flow sending receipts, and transmission end and receiving terminal respectively be provided with four with two antennas.The running of beam-forming device includes the following step:

Step 102: beginning;

Step 104: carry out a channel estimating at receiving terminal, to produce corresponding to a plurality of channel estimatings of a plurality of channels H as a result;

Step 106: determine a plurality of first candidate's transmission vector;

Step 108:, in a plurality of first candidate's transmission vector, choose one first transmission vector according to channel estimating H as a result

Step 110: determine a plurality of second candidate's transmission vector, and each second candidate's transmission vector is to be orthogonal to first transmission vector

Step 112:, in a plurality of second candidate's transmission vector, choose one second transmission vector according to channel estimating H as a result

Step 114: the size of adjusting first, second transmission vector ;

Step 116: transmit signal S1, S2, S3, S4 to produce four according to adjusted first, second transmission vector integral data stream D1, D2;

Step 118: on many antennas of transmission end, see off respectively and transmit signal S1, S2, S3, S4;

Step 120: finish.

As stated, at first, beam-forming device must carry out a channel estimating with a plurality of channel estimatings of producing corresponding a plurality of channels H as a result, and next, beam-forming device can determine a plurality of first candidate's transmission vector v ₁, and according to channel estimating as a result H from a plurality of first candidate's transmission vector v ₁In select first transmission vector Arbitrary first candidate's transmission vector that beam-forming device produced v ₁Be corresponding to 4 coefficient [v _1,1v _2,1v _3,1v _4,1] ^T, subscript wherein ^TExpression transposition (transposition), the corresponding antenna of numeral of subscript left, right-hand which the candidate's transmission vector of numeral of subscript; And be distributed on each antenna of transmission end first candidate's transmission vector in the present embodiment for the power averaging that makes data flow D1 v ₁The absolute value of each coefficient all be similar to a predetermined value " 1 ", therefore first candidate's transmission vector v ₁Each coefficient can produce according to follow procedure:

$v_{i,1}={\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H20051B8087320051108E000011.png"\; state="\{\{state\}\}">e</figure-callout>}}^{\frac{j}{}},$ N=1 ..., 4, i=1 ..., 4 equations (four)

Thus, beam-forming device can produce 4 at the most ⁴Plant first candidate's transmission vector v ₁Yet, note that to produce first candidate's transmission vector v ₁Mode do not exceed with present embodiment, for instance, beam-forming device also can limit each first candidate's transmission vector v ₁In only need the absolute value of 3 coefficients to be similar to a predetermined value, and this predetermined value viewable design demand is adjusted.Next, beam-forming device is to utilize a plurality of first candidate's transmission vector of the channel estimating rough reckoning of H as a result v ₁(Signal to Noise Ratio SNR), and selects first maximum candidate's transmission vector of signal to noise ratio to pairing signal to noise ratio v ₁As first transmission vector The mode of calculating signal to noise ratio can according to following equation for it:

γ ( v ₁)= v ₁ ^HH ^HH v ₁Equation (five)

In the equation (five), subscript ^HIt is expression conjugate transpose (conjugate transposition).Because γ is proportional to the pairing signal to noise ratio of transmission vector, so beam-forming device can be according to each first candidate's transmission vector v ₁Pairing γ size judges that what person has maximum signal to noise ratio.

When first transmission vector

After the decision, beam-forming device must further produce second transmission vector

At first, beam-forming device can determine a plurality of second candidate's transmission vector v ₂, each second candidate's transmission vector wherein v ₂All corresponding four coefficient [v _1,2v _2,2v _3,2v _4,2] ^T, and with first transmission vector

Quadrature, therefore selected second candidate's transmission vector v ₂Must meet following equation:

${{\underset{\&OverBar;}{v}}_2}^H{H}^{H}H{\stackrel{\&RightArrow;}{V}}_1=0$

Equation (six)

Wherein, each second candidate's transmission vector v ₂In have at least a coefficient be as orthogonal coefficient to satisfy equation (six), the absolute value of all the other coefficients then is similar to a predetermined value, so that the power averaging of data flow D2 is distributed on each antenna of transmission end.Suppose second candidate's transmission vector v ₂Coefficient v _4,2Be as orthogonal coefficient, all the other coefficient v then _1,2v _2,2v _3,2Can do combination in any according to following equation:

$v_{i,2}={\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H20051B8087320051108E000011.png"\; state="\{\{state\}\}">e</figure-callout>}}^{\frac{j}{}},$ N=1 ..., 4, i=1 ..., 3 equations (seven)

In addition, produce coefficient v _4,2Running be shown in following equation:

$v_{\mathrm{4,2}}={\left(\frac{\left[{v^{\&prime;}}_{\mathrm{1,2}}{v^{\&prime;}}_{\mathrm{2,2}}{v^{\&prime;}}_{\mathrm{3,2}}\right]H_r(1:\mathrm{3,1})}{H_r\left(\mathrm{4,1}\right)}\right)}^{\&prime;}$ Equation (eight)

Subscript wherein ' to get conjugation many in representative, and H _r=H ^HHv ₁, and H _r(n ₁: n ₂, 1) then represent H _rN ₁To n ₂Individual coefficient.Again if v _4,2=v _3,2Be orthogonal coefficient, then it can be tried to achieve according to following equation:

$v_{\mathrm{4,2}}=v_{\mathrm{3,2}}={\left(\frac{\left[{v^{\&prime;}}_{\mathrm{1,2}}{v^{\&prime;}}_{\mathrm{2,2}}\right]H_r(1:\mathrm{2,1})}{H_r\left(\mathrm{3,1}\right)+H_r\left(\mathrm{4,1}\right)}\right)}^{\&prime;}$ Equation (nine)

The selection of above-mentioned orthogonal coefficient can be at four coefficient [v _1,2v _2,2v _3,2v _4,2] ^TIn select arbitrarily, or select according to certain rule or order.Still please note; When the data flow of multiple input/output system transmission receipts surpasses two; Corresponding transmission vector also can increase, can analogize according to the foregoing description and produce other method that transmits vector, unique difference be the candidate of late generations transmit vector must with the vectorial quadrature of transmission of all previous generations; Therefore its degree of freedom is lower, that is the number that the candidate of more late generation transmits in the vector coefficient that can free appointment will successively decrease.Next, a plurality of channel estimatings of the same foundation of beam-forming device are H as a result, estimates each second candidate's transmission vector v ₂Pairing γ size, and come from this a plurality of second candidate's transmission vector v ₂Choose second candidate's transmission vector with maximum signal to noise ratio v ₂As second transmission vector The producing method of γ can be with reference to following equation:

γ ( v2)= v ₂ ^HH ^HH v ₂Equation (ten)

Please pay special attention to, from a plurality of first, second candidate's transmission vector v ₁, v ₂In select first, second transmission vector Foundation be not limited in its corresponding signal to noise ratio, other can all can be used as according to the numerical value that channel estimating bearing reaction receiving terminal receives signal quality and select first, second transmission vector of adjustment

Foundation.

After first, second transmission vector all produced, beam-forming device can be further adjusted the size of first, second transmission vector

according to the pairing γ of first, second transmission vector (also or signal to noise ratio).Suppose that first transmission vector

is to correspond to γ 1 and second transmission vector is to correspond to γ 2, then adjusted first, second transmission vector

can be represented it by following equation (11) or equation (12):

${{\stackrel{\&RightArrow;}{V}}_1}^{\&prime;}=\frac{{\stackrel{\&RightArrow;}{V}}_1}{\sqrt[4]{\mathrm{\&gamma;}1}}$ Equation (11)

${{\stackrel{\&RightArrow;}{V}}_2}^{\&prime;}=\frac{{\stackrel{\&RightArrow;}{V}}_2}{\sqrt[4]{\mathrm{\&gamma;}2}}$ Equation (12)

${{\stackrel{\&RightArrow;}{V}}_1}^{\&prime;}=\frac{{\stackrel{\&RightArrow;}{V}}_1}{\sqrt[8]{\mathrm{\&gamma;}1}}$ Equation (13)

${{\stackrel{\&RightArrow;}{V}}_2}^{\&prime;}=\frac{{\stackrel{\&RightArrow;}{V}}_2}{\sqrt[8]{\mathrm{\&gamma;}2}}$ Equation (14)

Wherein, when antenna number equation capable of using (11)～(12) during greater than number of data streams, on the contrary equation then capable of using (13)～(14), so this non-limitation of the present invention.Still please note; The adjustment mode of first, second transmission vector

is not exceeded with the foregoing description, and other can all can be used herein according to the adjustment mode that signal to noise ratio is adjusted the size of first, second transmission vector .At last; Beam-forming device be according to adjusted first, second transmission vector integral data stream D1, D2 producing a plurality of transmission signal S1, S2, S3, S4, and on 4 antennas of this transmission end, send out respectively and transmit signal S1, S2, S3, S4.

See also Fig. 3, Fig. 3 is the functional block diagram for a preferred embodiment of beam-forming device 200 of the present invention.As shown in the figure, beam-forming device 200 includes channel estimator 202, transmission vector generation module 210,220, weighted units 230 and data processing module 240.Include candidate's transmission vector generation unit 212, signal to noise ratio arithmetic element 214, comparing unit 216 in the transmission vector generation module 210 in addition and choose unit 218, and include candidate's transmission vector generation unit 222, signal to noise ratio arithmetic element 224, comparing unit 226 in the transmission vector generation module 220 in addition and choose unit 228.At first; Channel estimator 202 can produce channel estimating H as a result; And candidate's transmission vector generation unit 212 can produce a plurality of first candidate's transmission vector, and a plurality of first candidate's transmission vector are sent to signal to noise ratio arithmetic element 214 to calculate the pairing signal to noise ratio γ of each first candidate's transmission vector.Next; Comparing unit 226 can be found out the maximum γ 1 in a plurality of signal to noise ratios; Then by choose unit 228 from a plurality of first candidate's transmission vector select have one of maximum signal to noise ratio γ 1 person as first transmission vector

after first transmission vector produces; Candidate's transmission vector generation unit 222 can produce a plurality of second candidate's transmission vector with the first transmission vector quadrature ; Signal to noise ratio arithmetic element 224 can be calculated the pairing signal to noise ratio γ of each second candidate's transmission vector then, and a plurality of signal to noise ratios are sent to comparing unit 226 to find out the maximum γ 2 among a plurality of signal to noise ratio γ.Then; Choose unit 228 just can from a plurality of second candidate's transmission vector select have one of maximum signal to noise ratio γ 2 person as second transmission vector

after first, second transmission vector

all produces, weighted units 230 is just according to the size of signal to noise ratio γ 1, γ 2 first, second transmission vector of adjustment

.At last; Data processing module 240 can produce a plurality of transmission signal S1, S2, S3, S4 with data flow D1, D2 according to adjusted first, second transmission vector , and utilizes a plurality of antennas 252,254,256,258 of transmission end will transmit signal S1, S2, S3, S4 to send.

Be noted that the some of beam-forming device 200 of the present invention is the transmission ends that are positioned at multiple input-output system, another then is the receiving terminal that is positioned at multiple input-output system partly.In the present embodiment, channel estimator 202, transmission vector generation module 210,220 and weighted units 230 are to be positioned at receiving terminal; And data processing module 240 is to be positioned at the transmission end; Therefore; Receiving terminal can be feedback first, second transmission vector

to the transmission end, but so that is positioned at transmission end data processing module 240 integral data stream D1, D2 to produce transmission signal S1, S2, S3, S4.Yet; In the another embodiment of the present invention; Channel estimator 202 is arranged on receiving terminal; And transmission vector generation module 210,220, weighted units 230, data processing module 240 are arranged on receiving terminal, and receiving terminal only need carry out channel estimating and the result of channel estimating is returned to the transmission end thus, carries out other work by the transmission end then and gets final product.

In addition; Beam-forming device of the present invention also can be applicable to multiplexing (the orthogonal frequency division multiplexing of orthogonal frequency-division multiplex; OFDM) system; That is utilize transmission vector to integrate the pairing data flow of each subcarrier in the ofdm system, changing the through-put power of formed ofdm signal on different antennae through reverse multiple sharp leaf thus can be more average, and then simplifies the complexity of high-frequency circuit.

The above is merely preferred embodiment of the present invention, and all equalizations of doing according to claim of the present invention change and modify, and all should belong to covering scope of the present invention.

Claims (5)

1. wave beam formation method that is applied to a multiple input-output system, this multiple input-output system includes a transmission end and a receiving terminal, and a plurality of this receiving terminals that send a signal to are transmitted via a plurality of channels in this transmission end, and this wave beam formation method includes:

Produce a plurality of channel estimating results that should a plurality of channels at this receiving terminal;

Determine a plurality of first candidate's transmission vector;

According to these a plurality of channel estimating results, these a plurality of first candidate's transmission vector are chosen one first transmission vector with maximum signal to noise ratio certainly;

Determine a plurality of second candidate's transmission vector, and each second candidate's transmission vector is to be orthogonal to this first transmission vector;

According to these a plurality of channel estimating results, choose one second transmission vector in these a plurality of second candidate's transmission vector certainly with maximum signal to noise ratio; And

Handle one first data flow and one second data flow to produce these a plurality of transmission signals according to this first transmission vector and this second transmission vector.

2. wave beam formation method as claimed in claim 1, wherein, this first transmission vector is to be corresponding to one second signal to noise ratio corresponding to one first signal to noise ratio and this second transmission vector, and this wave beam formation method includes in addition:

Recently adjust the size of this first transmission vector or this second transmission vector according to this first, second noise.

3. wave beam formation method as claimed in claim 2, wherein, the step of adjusting this first transmission vector or this second transmission vector includes:

When this first signal to noise ratio during, dwindle this first transmission vector or amplify this second transmission vector greater than this second signal to noise ratio; And

When this first signal to noise ratio during, amplify this first transmission vector or dwindle this second transmission vector less than this second signal to noise ratio.

4. beam-forming device that is applied to a multiple input-output system, this multiple input-output system includes a transmission end and a receiving terminal, and a plurality of this receiving terminals that send a signal to are transmitted via a plurality of channels in this transmission end, and this beam-forming device includes:

One channel estimator is used for producing to a plurality of channel estimating results that should a plurality of channels;

One first transmission vector generation module is coupled to this channel estimator, with deciding a plurality of first candidate's transmission vector, and according to choosing one first transmission vector with maximum signal to noise ratio in oneself these a plurality of first candidate's transmission vector of this a plurality of channel estimating results;

One second transmission vector generation module; Be coupled to this channel estimator and this first transmission vector generation module; Use and decide a plurality of second candidate's transmission vector that are orthogonal to this first transmission vector, and in these a plurality of second candidate's transmission vector, choose one second transmission vector with maximum signal to noise ratio according to these a plurality of channel estimating results; And

One data processing module; Be coupled to this first transmission vector generation module and this second transmission vector generation module, be used for handling one first data flow and one second data flow to produce these a plurality of transmission signals according to this first transmission vector and this second transmission vector.

5. beam-forming device as claimed in claim 4, wherein, this first transmission vector is to be corresponding to one second signal to noise ratio corresponding to one first signal to noise ratio and this second transmission vector, and this beam-forming device includes in addition:

One weighted units; Couple this first transmission vector generation module, this data processing module and this second transmission vector generation module respectively; When this first signal to noise ratio during greater than this second signal to noise ratio, this weighted units is dwindled this first transmission vector or is amplified this second transmission vector; When this first signal to noise ratio during less than this second signal to noise ratio, this weighted units is amplified this first transmission vector or is dwindled this second transmission vector.

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