CN101715641B - A method of performing phase shift-based precoding and an apparatus for supporting the same in a wireless communication system - Google Patents

Abstract

The invention discloses a method of transmitting data using a phase shift-based precoding in a multiple antenna system using a plurality of subcarriers. More specifically, the method includes determining a diagonal matrix to provide different phase angles to each of the plurality of antennas as a part of a phase shift-based precoding matrix, selecting a unitary matrix from a first codebook as the part of a phase shift-based precoding matrix, and performing precoding to symbols associated with subcarriers based on the diagonal matrix and the unitary matrix.

Description

In wireless communication system, carry out based on the method for the precoding of phase shift and support its equipment

Technical field

The present invention relates to a kind of execution based on the method for the precoding of phase shift, relate in particular to the method is supported in a kind of execution based on the method for the precoding of phase shift and in wireless communication system equipment.

Background technology

Along with the purposes of numerous multimedia services and being widely used of population in use growth and communication service, the demand of wireless service increases sharply.In order to contain the demand of change, most important is exactly the capacity that increases communication system.The method of increase capacity comprises looks for new available bandwidth, and the efficient of improving existing resource.

As the example of improving the existing resource use, transmitter and receiver can be equipped with the resource in the next effective usage space territory of many antennas, to obtain diversity gain.Moreover many antennas allow data communication device to cross each antenna parallel transmission, increase transmission capacity with this.

About the method for using multi-antenna transmission and receive data can be by using OFDM (Orthogonal Frequency Division Multiplexing, OFDM) multiple-input and multiple-output (Multi Input, Multi Output, MIMO) system is represented.

Summary of the invention

Technical scheme

Therefore, the invention relates to the method is supported in a kind of execution based on the method for the precoding of phase shift and in wireless communication system equipment, it is substantially avoided because the restriction of correlation technique and one or more problem that shortcoming causes.

One object of the present invention is to be provided in the multiaerial system with a plurality of subcarriers uses the method for coming the transmission of data based on the precoding of phase shift.

Other purpose of the present invention is to be provided in the multiaerial system with a plurality of subcarriers uses the equipment that comes the transmission of data based on the precoding of phase shift.

In following explanation, will disclose part other advantage of the present invention, purpose and feature, and for originally with regard to the personage who is proficient in this technology, some part just can be understood from the following example, perhaps implements the present invention and just knows.Structure by written explanation neutralizes and particularly points out in its claim scope and the accompanying drawing so just can realize and obtain purpose of the present invention and other advantage.

In order to reach these purposes and other advantage, and according to purpose of the present invention, such as herein enforcement and broadly described, use the precoding based on phase shift to come the method for the transmission of data to comprise in the multiaerial system with a plurality of subcarriers: the phase angle that is identified for providing different is to each the diagonal matrix in a plurality of antennas, with as the part based on the pre-coding matrix of phase shift; Select in the first code book unitary matrice with as the part based on the pre-coding matrix of phase shift; And come the relevant symbol of subcarrier is carried out precoding according to described diagonal matrix and described unitary matrice.

In other side of the present invention, in the multiaerial system with a plurality of subcarriers, use the precoding based on phase shift to come the equipment of the transmission of data to comprise: the pre-coding matrix determination module, it is configured to be identified at least one the diagonal matrix in phase shift and the code book, and described pre-coding matrix based on phase shift is take described diagonal matrix and unitary matrice as the basis; And precoding module, it is configured to come the relevant symbol of subcarrier is carried out precoding according to described diagonal matrix and described unitary matrice.

Can understand, the above-mentioned general remark of the present invention and following execution mode all only are exemplary and exemplary, are used for providing the further explanation to claim of the present invention.

Description of drawings

The included accompanying drawing of the present invention is used for providing a further understanding of the present invention, and they are bonded to this part that has also consisted of this specification, and these accompanying drawings show embodiments of the invention, and is used from explanation principle of the present invention with specification one.

In the accompanying drawings:

Fig. 1 is the transmitter of explanation mimo system and the exemplary plot of receiver structure;

Fig. 2 is the exemplary plot of the transmitter of the multiaerial system of explanation use CDD scheme;

Fig. 3 is the exemplary plot of the application of explanation phase sequence;

Fig. 4 is for illustrating that use is based on the transmitter of the multiaerial system of the pre-coding scheme of code book and the exemplary plot of receiver;

Fig. 5 is used for execution based on the transmitter of the precoding of phase shift and the exemplary plot of receiver for explanation;

Fig. 6 is two kinds of exemplary plot based on the precoding of phase shift based on the time extension sample size of explanation;

Fig. 7 uses the exemplary plot based on transmitter and the receiver of SCW OFDM based on the precoding of phase shift for explanation; And

Fig. 8 uses the exemplary plot based on transmitter and the receiver of MCW OFDM based on the precoding of phase shift for explanation.

The preferred forms of invention

Other features and advantages of the present invention will be illustrated in the following description, and its part can be understood from explanation, maybe can obtain by implementing the present invention.Purpose of the present invention and other advantages can realize by the structure of specifically noting in specification and claim and the accompanying drawing and obtain.

To in detail with reference to preferred embodiment of the present invention, in the accompanying drawing its example will be described at this.No matter somewhere, in institute's drawings attached, will represent with identical Reference numeral same or analogous part.

Fig. 1 is the exemplary plot of the structure of transmitter and receiver in the explanation mimo system.Please refer to Fig. 1, transmitter comprises channel encoder 101, mapper 103, string also (Serial-to-parallel, S/P) transducer 105 and many antenna encoder 107.Especially, channel encoder 101 can be attached to the transmission of data bit with repeating (or extra) bit, so that the interference that minimizing channel and/or noise cause.Mapper 103 can convert data bit to data symbol, but and S/P transducer 105 array data symbols distribute to subcarrier.Spacing wave when at last, many antenna encoder 107 can convert the data symbol of arranging side by side to.

In addition, this receiver comprise many antenna decoder 109, and the string (Parallel-to-serial, P/S) transducer 111, de-mapping device 113 and channel decoder 115.The function of many antenna decoder 109 of receiver, P/S transducer 111, de-mapping device 113 and channel decoder 115 respectively with the functions reversed of many antenna encoder 107, S/P transducer 105, mapper 103 and the channel encoder of transmitter, therefore will description is omitted.

In many antenna OFDM Systems, can increase with many modes the reliability of transfer of data.These methods comprise Space Time Coding (Space-time Code, STC) scheme and circulation delay diversity (Cyclic Delay Diversity, CDD) scheme.STC and CDD scheme can be used to obtain space diversity.Further, these methods comprise in addition wave beam and form scheme and pre-coding scheme, and this all is used for increasing signal to noise ratio (Signal-to-noise, SNR).

STC and CDD scheme generally not needing to be used for the open cycle system of feedback information, to increase the reliability of the transmission of data.Moreover wave beam forms scheme and pre-coding scheme generally is used for using feedback information with the optimized closed-loop system of SNR.

Especially, for the method that increases space diversity gain and SNR, below in detail CDD and pre-coding scheme will be discussed respectively.

At first, the ofdm signal that the CDD scheme allows each antenna transmission of multiaerial system to have different delayed time or have different sizes, so receiver can be obtained frequency diversity gain.

Fig. 2 is the exemplary plot of the transmitter of the multiaerial system of explanation use CDD scheme.

After the OFDM symbol is processed through S/P transducer and many antenna encoder and then is launched by each antenna, when being transferred to receiver, can add at the OFDM symbol (or enclosing) Cyclic Prefix (Cyclic Prefix, CP).CP can join the OFDM symbol and disturb in the channel avoiding.At this, be sent to the first antenna and do not enclose CP with the data sequence that is used for transmitting on it, but be sent to follow-up antenna with the data sequence that is used for transmitting just affix CP.Namely, the data sequence that is sent to follow-up antenna is attached with the circulation time-delay bit of specified quantitative.

If this circulation time-delay scheme is applied in frequency domain, then the multiple of available phases sequence represents the circulation time-delay.Fig. 3 is the exemplary plot of the application of explanation phase sequence.See also Fig. 3, in frequency domain, there is each process in the different phase sequences (for example phase sequence 1～phase sequence M) that dispose multiplexing according to antenna, then be applied to inverse fast fourier transform (Inverse FastFourier Transform, IFFT).After this, switched data can transfer to receiver, and this processing of Fig. 3 can be described as the phase shift diversity scheme.

If use the phase shift diversity scheme, then flat fading channel can convert frequency selective channel to.In addition, frequency diversity gain can be obtained by chnnel coding, and/or multi-user diversity gain can be obtained by the frequency selection scheduling.

The second, the precoding method comprises based on the pre-coding scheme of code book and quantization scheme.Especially, if during the feedback information of closed-loop system of feedback fixed amount, then can use the pre-coding scheme based on code book.In addition, quantization scheme can be used for the channel information of feedback quantization.To be sent to transmitter as the index of the pre-coding matrix (it is known for transmitter and receiver) of feedback information based on the pre-coding scheme of code book, to obtain the SNR gain.

Fig. 4 is for illustrating that use is based on the transmitter of the multiaerial system of the pre-coding scheme of code book and the exemplary plot of receiver.See also Fig. 4, each all has the pre-coding matrix (P for example of limited quantity transmitter and receiver ₁-P _L).The operation on, receiver with channel information as feedback information best pre-coding matrix index (for example " index 1 ") is sent to transmitter.In response, transmitter is applied to index 1 the corresponding the transmission of data (X of pre-coding matrix ₁-X _Mt).

Table 1 is applicable code book example when supporting that two (2) transmitting antennas and spatial multiplex ratio are the feedback information of use 3 bits in 2 the system (for example IEEE 802.16e system).

[table 1]

As what discuss, the phase shift diversity scheme is used in obtains the gain of frequency selection diversity in the closed loop, and also obtains the frequency scheduling diversity gain.But, spatial multiplex ratio 1 is used for the phase shift diversity scheme, therefore can't expect with the high transmission rates the transmission of data.In addition, if the fixed allocation resource then is difficult to come expected frequence to select and the frequency scheduling diversity gain with the phase shift diversity scheme.

Further, as what discuss, can use a small amount of feedback information (or index information) and have the high spatial reusability based on the pre-coding scheme of code book, therefore the transmission of data effectively.But, thus need stable channel situation because rely on feedback information, if the method can meet with difficulty when channel situation was unstable.Further, this pre-coding scheme based on code book is subject to and can only be applied in closed-loop system.

In order to solve the phase shift diversity scheme and/or based on these relevant potential problems of the pre-coding scheme of code book, therefore to provide following discussion.

Fig. 5 is used for execution based on the transmitter of the precoding of phase shift and the exemplary plot of receiver for explanation.Especially, be exactly that the out of phase sequence is multiplied by will be by the data flow of each transmission in a plurality of antennas based on the precoding of phase shift.Generally speaking, use the partial circulating delay value to produce phase sequence.In this case, from the viewpoint of receiver, can obtain the frequency selection diversity, and the size of channel increases or reduces according to frequency domain.

With reference to figure 5, transmitter can utilize the part that receiver (for example mobile device) is disposed channel situation good (maybe can accept) to the frequency domain, obtains the scheduling diversity.At this, the specific portion of frequency domain has larger frequency range and can not be subject to the impact of relatively little circulation delay value fluctuation.For the circulation delay value that will increase or reduce as one man is applied to each antenna, can use the pre-coding matrix P based on phase shift, as shown in Equation 1.

[formula 1]

See also formula 1, k represents the index of subcarrier or the index of specific frequency range, and W _{I, j} ^k(i=1 ..., N _t, j=1,1 ..., R) the representative complex weighted value definite according to k.Moreover, N _tRepresent the quantity of transmitting antenna or virtual-antenna, and R represents spatial multiplex ratio.At this, complex weighted value can be according to the index of OFDM symbol and the corresponding subcarrier that is multiplied by antenna.In addition, complex weighted value can be determined by channel situation and/or feedback information.Be preferably, the pre-coding matrix P of formula 1 is configured to use unitary matrice, so reduces the channel capacity loss of multiaerial system.

Following formula can be used for representing the channel capacity of multi-antenna closed system, so defines the element (or composition) of unitary matrice.

[formula 2]

$\mathrm{Cu}\left(H\right)={\log }_2\left(\det (I_{N_r}+\frac{\mathrm{SNR}}{N}{\mathrm{HH}}^H)\right)$

See also formula 2, the H representative is of a size of N _rXN _tThe multi-antenna channel matrix, and N _rRepresent reception antenna quantity.If formula 2 is applied to the pre-coding matrix P based on phase shift, then available formula 3 expressions of result.

[formula 3]

$C_{\mathrm{precoding}}={\log }_2\left(\det (I_{N_r}+\frac{\mathrm{SNR}}{N}{\mathrm{HPP}}^H{H}^H)\right)$

See also formula 3, in order to reduce or to eliminate channel capacity loss, PP ^HBe necessary for unit matrix.So, must satisfy the condition of following formula 4 based on the matrix P of phase shift.

[formula 4]

PP ^H＝I _N

In order to allow the pre-coding matrix P based on phase shift convert unit matrix to, must satisfy 2 conditions.Namely, must satisfy simultaneously Power Limitation condition and quadrature restrictive condition.The Power Limitation condition is about allowing the size of each row of matrix equal 1.Moreover the quadrature restrictive condition is about allowing each be listed as all quadratures (or being listed as orthogonal).Formula 5 and formula 6 are the example of these conditions.

[formula 5]

${\left|w_{\mathrm{1,1}}^k\right|}^2+{\left|w_{\mathrm{2,1}}^k\right|}^2+\·\·\·+{\left|w_{N_t,1}^k\right|}^2=1,$

${\left|w_{\mathrm{1,2}}^k\right|}^2+{\left|w_{\mathrm{2,2}}^k\right|}^2+\·\·\·+{\left|w_{N_t,2}^k\right|}^2=1,$

${\left|w_{1,R}^k\right|}^2+{\left|w_{2,R}^k\right|}^2+\·\·\·+{\left|w_{N_t,R}^k\right|}^2=1,$

[formula 6]

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1,1}}^{k^{*}}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1,2}}^k+{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{2,1}}^{k^{*}}{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{2,2}}^k+\&CenterDot;\&CenterDot;\&CenterDot;+w_{N_t,1}^{k^{*}}{w}_{N_t,2}^k=0,$

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1,1}}^{k^{*}}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1,3}}^k+{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{2,1}}^{k^{*}}{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{2,3}}^k+\&CenterDot;\&CenterDot;\&CenterDot;+w_{N_t,1}^{k^{*}}{w}_{N_t,3}^k=0,$

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{1,1}}^{k^{*}}{\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">w</figure-callout>}}_{1,R}^k+{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{\mathrm{2,1}}^{k^{*}}{\mathrm{<figure-callout\; id="2"\; label="w"\; filenames="H2007800347316E00051.png"\; state="\{\{state\}\}">w</figure-callout>}}_{2,R}^k+\&CenterDot;\&CenterDot;\&CenterDot;+w_{N_t,1}^{k^{*}}{w}_{N_t,R}^k=0$

The above about the discussion of formula 2-6 about unitary matrice.Hereinafter, the discussion of unitary matrice be about matrix size 2x2 based on the pre-coding matrix of phase shift.

Formula 7 representative is about two transmitting antennas and have the pre-coding matrix based on phase shift of spatial multiplex ratio 2.

[formula 7]

$p_{2x2}^k=\left(\begin{array}{cc}{\mathrm{\&alpha;}}_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_1}& {\mathrm{\&beta;}}_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_2}\\ {\mathrm{\&beta;}}_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_3}& {\mathrm{\&alpha;}}_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_4}\end{array}\right)$

See also formula 7, α _i, β _i(i=1,2) represent real number, θ _i(i=1,2,3,4) represent the sub-carrier indices that phase value and k represent ofdm signal.

In order to convert this pre-coding matrix (for example formula 7) to unitary matrice, then must satisfy the Power Limitation condition of formula 8 and the quadrature restrictive condition of formula 9.

[formula 8]

${\left|a_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_1}\right|}^2+{\left|{\mathrm{\&beta;}}_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_3}\right|}^2=1,{\left|a_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_4}\right|}^2+{\left|{\mathrm{\&beta;}}_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_2}\right|}^2=1$

[formula 9]

${\left(a_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_1}\right)}^{*}+{\mathrm{\&beta;}}_1{e}^{\mathrm{jk}{\mathrm{\&theta;}}_2}=1+{\left({\mathrm{\&beta;}}_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_3}\right)}^{*}+a_2{e}^{\mathrm{jk}{\mathrm{\&theta;}}_4}=0$

In formula 8 and 9, ^*Represent the plural number of combination.If the pre-coding matrix based on phase shift possesses the 2x2 size that satisfies formula 7-9, this matrix can represent with following formula 10.

[formula 10]

$p_{2x2}^k=\frac{1}{\sqrt{2}}\left(\begin{array}{cc}1& e^{\mathrm{jk}{\mathrm{\&theta;}}_2}\\ e^{\mathrm{jk}{\mathrm{\&theta;}}_3}& 1\end{array}\right)$

See also formula 10, θ ₂And θ ₃Keep orthogonality relation according to satisfying the quadrature restrictive condition.This can be shown in the formula 11.

[formula 11]

kθ ₃＝-kθ ₂+π

Pre-coding matrix can be stored in the transmitter and receiver with the form of code book.Code book comprises the different θ of use ₂The certain number of value produces many pre-coding matrixes.At this, according to channel situation and whether provide feedback information to dispose θ ₂Value.If provide (or use) feedback information, then with θ ₂Value is configured to little value.If do not provide (or not using) feedback information, then with θ ₂Value is configured to large value, so obtains the high-frequency diversity gain.

In addition, obtain frequency diversity gain and/or frequency scheduling gain according to the time extension sample size that is applied to based on the pre-coding matrix of phase shift.Fig. 6 plants the exemplary plot based on the precoding of phase shift according to the time extension sample size for explanation two (2).

See also Fig. 6, if use large time extension sample size (or circulation time-delay), then utilize because frequency selects to shorten to allow the frequency selection cycle uprise, obtain the frequency diversity gain of channel symbol.Be preferably and in the open cycle system, use larger time extension sample, wherein because about channel serious time fluctuation is arranged, so feedback information is more unreliable.

Further, if use little time extension sample value, then channel can increase in flat fading channel or reduce from frequency selective channel and channel size.Moreover if the channel size in the specific subcarrier field of ofdm signal increases, then the channel size in other subcarrier field of ofdm signal reduces.In other words, its relation is inversely proportional to.

In this case, about OFDM (Orthogonal Frequency DivisionMultiple Access, OFDMA) system, if come signal transmission according to the frequency band that each user increases by channel size, then can increase SNR.In addition, the channel size that frequency range has increased is all different to each user, and the result is that system can obtain the scheduling diversity about the multidigit user.Further, receiver only need to transmit the feedback information relevant with the channel quality information that can carry out the subcarrier of resource distribution (Channel Quality Information, CQI).Therefore, the large I of feedback information reduces thereupon.

Time extension sample (or circulation time-delay) based on the precoding of phase shift can be the predetermined value in transmitter and the receiver, maybe can offer transmitter from receiver by feedback information.Further, space reusability R can be predetermined value on transmitter and receiver, or can regularly weigh after channel situation comes the computer memory reusability at receiver, offers transmitter by receiver as feedback information.At this, transmitter can calculate and/or the manipulation space reusability with the channel information from the receiver feedback.

The phase shift diversity of broad sense (Generalized Phase Shift Diversity, GPSD)

As mentioned above, the pre-coding matrix based on phase shift is according to having N _tIndividual antenna (N _tMore than or equal to 2 and be natural number) and the system of spatial multiplex ratio R (R＞1 and for natural number).This system can represent according to formula 12.

[formula 12]

See also formula 12,

Representative has N _tBroad sense phase shift diversity (GPSD) matrix of k subcarrier in the MIMO-OFDM signal of individual transmitting antenna and spatial multiplex ratio R.

Moreover, For satisfying

Unitary matrice, and the internal symbol that is used for dwindling between the sub-carrier is disturbed.Especially,

Also should satisfy the unitary matrice condition, so can keep the unitary matrix properties of the diagonal matrix of phase shift.

Formula 13 represents the phase angle θ in formula 12 medium frequency territories _i, i=1 ..., N _tTime delay τ with time-domain _i, i=1 ..., N _tBetween relation.

[formula 13]

${\mathrm{\&theta;}}_i=\frac{-2\mathrm{\&pi;}}{N_{\mathrm{fft}}}\&CenterDot;{\mathrm{\&tau;}}_i$

See also formula 13, N _FftRepresent the number of subcarriers of ofdm signal.

As the example of formula 12, formula 14 representatives have two (2) transmitting antennas of use 1 bit code book or the system of virtual-antenna.

[formula 14]

${\mathrm{GPSD}}_{2X2}^k=\left(\begin{array}{cc}\mathrm{\&alpha;}& \mathrm{\&beta;}\\ \mathrm{\&beta;}& -\mathrm{\&alpha;}\end{array}\right),{\mathrm{\&alpha;}}^2+{\mathrm{\&beta;}}^2=1$

See also formula 14, in case because α determines that β just can determine easily that α is predeterminable to be two values, and the form of the Information Availability code book index of relevant default value feedback.For example: if the feedback code book index be that 0, α can be 0.2, and if the feedback code book index be 1, then α can be 0.8.These values can be between transmitter and receiver agreement with share.

About formula 12, use unitary matrice

The example of specific pre-coding matrix (for example WalshHadamard matrix or discrete Fourier transform (DFT)) obtains the SNR diversity.

If use Walsh Hadamard matrix, then the GPSD matrix can be illustrated in the formula 15 about the example of formula 12.

[formula 15]

${\mathrm{GPSD}}_{4\&times;4}^k=\frac{1}{\sqrt{4}}\left(\begin{array}{cccc}{e}^{j{\mathrm{\&theta;}}_1\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0& 0& 0\\ 0& e^{j{\mathrm{\&theta;}}_2\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0& 0\\ 0& 0& e^{j{\mathrm{\&theta;}}_3\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0\\ 0& 0& 0& e^{j{\mathrm{\&theta;}}_4\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="H2007800347316E00032.png,H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}\end{array}\right)\left(\begin{array}{cccc}1& 1& 1& 1\\ 1& -1& 1& -1\\ 1& 1& -1& -1\\ 1& -1& -1& 1\end{array}\right)$

See also formula 15, this formula is based on according to (4) individual transmission or virtual-antenna and spatial multiplex ratio 4.At this, second matrix on equal sign the right (for example be expressed as 1s with-1s) can be reconfigured to select specific antenna (for example day line options) and/or adjust spatial multiplex ratio (for example ratio adjustment).

The unitary matrice of formula 12

The form of available code book offers transmitter and receiver.At this, transmitter can receive from receiver the index information of code book.After this, transmitter can be from the unitary matrice of codebook selecting manipulative indexing, and application of formula 12 disposes the pre-coding matrix based on phase shift.

The unitary matrice that formula 16 expressions reconfigure is used for selecting two (2) individual antennas in the system with four (4) individual transmission or virtual-antenna.

[formula 16]

$P_{4\&times;4}^k=\frac{1}{\sqrt{4}}\left(\begin{array}{cccc}{e}^{j{\mathrm{\&theta;}}_1\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0& 0& 0\\ 0& e^{j{\mathrm{\&theta;}}_2\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0& 0\\ 0& 0& e^{j{\mathrm{\&theta;}}_3\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}& 0\\ 0& 0& 0& e^{j{\mathrm{\&theta;}}_4\mathrm{<figure-callout\; id="0"\; label="k"\; filenames="H2007800347316E00041.png"\; state="\{\{state\}\}">k</figure-callout>}}\end{array}\right)\left(\begin{array}{cccc}0& 0& 1& 1\\ 0& 0& 1& -1\\ 1& 1& 0& 0\\ 1& -1& 0& 0\end{array}\right)$

Further, unlikely and change in time and/or channel condition if following table 2 shows spatial multiplex ratios, a kind of reusability according to correspondence reconfigures the method for unitary matrice.

[table 2]

See also table 2, select first row, the first and second row and/or the first to the 4th row according to reusability (for example 1,2 or 4 reusability).But, reusability (or row selection) is not limited to the example of table 2, and reusability can be one (1) and can select arbitrary row in four row.Moreover, if reusability is (2), then can select wantonly two row (for example 1-2,2-3,3-4 or 4-1) in four row.

In above-listed example, use (Wo Shihadema) Walsh Hadamard matrix, following example shows the GPSD matrix, wherein has the unitary matrice of 2x2 or 4x4 Walsh code

Be applied to formula 12.At this, table 2 represents 2x2 and table 3 represents 4x4.

[table 3]

[table 4]

The GPSD that time is variable

The phase angle θ of the GPSD matrix of formula 12 _iAnd/or unitary matrice U can become in time.In other words, phase angle θ _iAnd/or unitary matrice U can be the time independently.Variable GPSD of time is presented in the formula 17 about the example of formula 12.

[formula 17]

See also formula 17,

Representative has N in special time t _tThe GPSD matrix of k subcarrier in the MIMO-OFDM signal of individual transmission/virtual-antenna and spatial multiplex ratio R.Moreover, For satisfying

Unitary matrice, and be used for dwindling sub-carrier between internal symbol disturb.Especially, Also should satisfy the unitary matrice condition, so can keep the unitary matrix properties of the diagonal matrix of phase shift.

Formula 18 represents the phase angle θ in formula 12 medium frequency territories _i, i=1 ..., N _tTime delay τ with time-domain _i, i=1 ..., N _tBetween relation.

[formula 18]

${\mathrm{\&theta;}}_i=\frac{-2\mathrm{\&pi;}}{N_{\mathrm{fft}}}\&CenterDot;{\mathrm{\&tau;}}_i\left(t\right)$

See also formula 18, N _FftRepresent the number of subcarriers of ofdm signal.

Shown in formula 17 and 18, time delays sample value and unitary matrice can be passed through in time and be become, and chronomere can be illustrated in OFDM symbolic unit or the special time unit.

Application has the unitary matrice of 2x2 or 4x4 Walsh code and comes the GPSD matrix example of variable GPSD of acquisition time to be presented in table 5 and the table 6 respectively.

[table 5]

[table 6]

Enhancement mode GPSD

Within comprising the GPSD matrix of diagonal matrix and unitary matrice, shown in the formula 12, add the 3rd matrix, form enhancement mode GPSD matrix.Enhancement mode GPSD matrix can be shown in the formula 19.

[formula 19]

See also formula 19 and with formula 12 relatively, enhancement mode GPSD matrix comprised one and has big or small N before diagonal matrix _tThe pre-coding matrix P of xR.Therefore, the size of diagonal matrix becomes RxR.Further, the new pre-coding matrix that adds

Can there be different configurations to be used for specific frequency range or specific subcarrier symbol.Moreover, the new pre-coding matrix that adds Can be configured to the unitary matrice in the closed-loop system.Newly-increased or comprise pre-coding matrix

Lower, can obtain best SNR gain.

In addition, can a plurality of pre-coding matrixes will be comprised Code book offer transmitter and receiver.

In enhancement mode GPSD matrix, the phase angle θ of at least one pre-coding matrix P, diagonal matrix and the phase angle of unitary matrice U can change in time.For this reason, if the index of follow-up (or next) pre-coding matrix P feeds back to transmitter with predetermined time unit or predetermined subcarrier unit, then can be from the specific pre-coding matrix P of selection in the code book from manipulative indexing.In the case, enhancement mode GPSD matrix can be shown in the formula 20.

[formula 20]

See also formula 20, proposition was numbered the detailed description that enhancement mode GPSD is arranged in the korean patent application case of 10-2007-0037008 on April 16th, 2007.For this reason, the discussion of enhancement mode GSPD will be omitted.

The configuration of the phase shift relation of each antenna

The below discusses each phase angle θ of the diagonal matrix of explanation GPSD, variable GPSD of time, enhancement mode GPSD and enhancement mode time possibility GPSD _NtFor simplicity, this discussion is to be the basis to close about the phase shift of each antenna of variable GPSD of time, but also can be applicable in above-listed other GPSD form.

Phase shift relation configuration-specific embodiment 1

The phase angle of variable GPSD of time is configured to come linear increase according to the index of each antenna.Relation between each phase angle all available mathematical way represents, and can be shown in the formula 25.

[formula 25]

θ ₁(t)＝0·θ(t)，θ ₂(t)＝1·θ(t)

θ ₃(t)＝2·θ(t)，?θ ₄(t)＝3·θ(t)

Especially, this specific embodiment can be obtained high energy power in the single linear array antenna structure.Especially, if spatial multiplex ratio is configured or is reconfigured for little (or low), such as the situation in the table 2, then can obtain the optimum beam gain.Further, if unitary matrice U is set or is reconfigured as the antenna selection type, shown in the formula 16, then can obtain high-gain.

Phase shift relation configuration-specific embodiment 2

The phase angle of variable GPSD of time can be configured by the phase angle that replaces between even number antenna and the odd number antenna and has the same phase angle.In the system with four antennas, the relation between each phase angle all available mathematical way represents, and can be shown in the formula 26.

[formula 26]

θ ₁(t)＝0·θ(t)，θ ₂(t)＝1·θ(t)

θ ₃(t)＝0·θ(t)，θ ₄(t)＝1·θ(t)

See also formula 26, the first antennas and third antenna and have the same phase angle, and the second and the 4th antenna has the same phase angle.In this specific embodiment, if channel power is higher, then system possesses high-effect in block diagonal angle channel type (for example cross polarity antenna).

Phase shift relation configuration-specific embodiment 3

It is different from the phase angle of other antenna that the phase angle of variable GPSD of time can be configured to the phase angle of specific antenna.In the case, all relations at phase angle all can be shown in the formula 27.

[formula 27]

θ ₁(t)＝1·θ(t)，θ ₂(t)＝0·θ(t)

θ ₃(t)＝1·θ(t)，θ ₄(t)＝1·θ(t)

See also formula 27, if the correlation between the antenna of the second index and other antenna is too high, then the phase angle of the second antenna is configured to different from the phase angle of other antenna.According to this specific embodiment, if the correlation between specific antenna and other antenna is not low, then can obtain high beam gain.

Above-mentioned specific embodiment has been discussed the phase angle relationship that disposes each antenna, with the structure corresponding to transmitting antenna.But, can carry out different settings to each antenna according to the phase shift relation of antenna.Further, also can carry out different settings to the per unit time according to the phase shift relation of antenna, and when carrying out, consider channel condition and/or annoyance level according to antenna.At last, the phase shift relation according to antenna can be configured to corresponding to each frequency band of distributing to each antenna.

The configuration of time delay and/or unitary matrice

Time delay τ about GPSD _iWith unitary matrice U _NtxR, can be according to many conditions different or independently mode determine the time delay τ of variable GPSD of time _i(t) and unitary matrice U _NtxR(t) and the time delay τ of enhancement mode GPSD _i, τ _iAnd unitary matrice (U (t)) _NtxR, U _NtxR(t)).Below discussion is time delay and/or the unitary matrice about GPSD; But, identical discussion also can be applied to variable GPSD of time and enhancement mode GPSD.

Configuration-the specific embodiment 1 of time delay and/or unitary matrice

Be similar to ofdm system, if according to subcarrier use different frequency bands (1.25MHz for example, 5MHz, 10MHz ..., 100MHz), then can be according to each system's frequency range by different way time delay and/or the unitary matrice of GP configuring SD.But, time delay is used identical value in can be during special time, and no matter frequency band, and only have unitary matrice to carry out different configurations according to each frequency band.Concise and to the point, the time delay of GPSD and unitary matrice can be by separate configurations.

Configuration-the specific embodiment 2 of time delay and/or unitary matrice

If base station (Base Station, BS) distributes also notice mobile radio station (Mobile Station, MS) special time and/or specific unitary matrice, the then time delay and/or the unitary matrice that provide of the configurable BS of MS, and accordingly transmission.

If the data volume (for example feedback information) that BS receives surpasses buffer size, for example then need again the transmission of data of MS.List this possibility in consideration, can determine the value that special time postpones and/or unitary matrice is relevant.

Configuration-the specific embodiment 3 of time delay and/or unitary matrice

BS can determine time delay and/or unitary matrice with reference to the feedback information that transmits from MS.Moreover BS can use definite time delay and/or unitary matrice at the inside the transmission of data of downlink side.But the feedback information periodic transmission, and BS can reconfigure time delay and/or unitary matrice at every turn when receiving feedback information.

Configuration-the specific embodiment 4 of time delay and/or unitary matrice

Come the respectively time delay of GP configuring SD according to the resource of distributing to transmitter (for example BS or MS).For example: if it is more to distribute to the resource of transmitter, the possibility that subcarrier interference then occurs is just little, so time delay can be set as 0 or quite little value.In addition, if the resource of distributing is less, then can set larger time delay, so reduce inner subcarrier interference.

Configuration-the specific embodiment 5 of time delay and/or unitary matrice

BS can select specific unitary matrice as the unitary matrice of GPSD.Especially, can select and/or use the particular column of selected unitary matrice.

Shown in the table 2, determine columns according to the reusability during the transfer of data.BS can determine the specific unitary matrice that GPSD will use, and can be with reference to the reusability from the MS feedback, so that definite columns for the unitary matrice of choosing corresponding to this reusability.In addition, BS can be with selecteed listing (or subindex of row) the information notice MS of the information (or index of unitary matrice) on the unitary matrice of selecting and corresponding unitary matrice.

At this, if the data volume (for example feedback information) that BS receives surpasses buffer size, for example then need again the transmission of data of MS.List this possibility in consideration, can select the particular column of specific unitary matrice and/or corresponding unitary matrice.

Configuration-the specific embodiment 6 of time delay and/or unitary matrice

The time delay of GPSD and unitary matrice can provide essential value to come the mode of the transmission of data to carry out to MS and MS with the value of providing during network enters according to BS wherein.In addition, BS can determine essential value and use these values at the inside the transmission of data of downlink side.

Configuration-the specific embodiment 7 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to reusability.For example: if reusability is 1, then time delay is set as 1/2, and if reusability be 2, then time delay is set as 1/4.This specific embodiment can be used in conjunction with wherein selecting the specific embodiment 5 from the particular column of unitary matrice.

Configuration-the specific embodiment 8 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the data configuration method.For example: if the signal distributions of MS and configuration by frequency domain, in order to obtain frequency diversity gain, and that time delay can be set is relatively large with frequency diversity gain effectiveness optimization.Moreover if utilize MS signal compact configuration in frequency domain and utilize the MS signal configures is searched the frequency scheduling gain in the frequency domain with excellent channel interval, then time delay can be set as less, so will dispatch gain optimization.

Configuration-the specific embodiment 9 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the translational speed of MS.For example: if the ambulant speed of MS is unhappy, then because inner subcarrier interference is quite little, so that time delay can be set as is less.In addition, if the ambulant speed of MS is not slow, then because inner subcarrier interference is quite large, so that time delay can be set as is larger.

Configuration-the specific embodiment 10 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the kind of multiaerial system.For example: if use sole user MIMO, so then because need to consider that the relatively not high time delay of inner subcarrier interference can be set as little value, such as the situation of STC.In addition, if use multiuser MIMO (for example single minute multiple access), then because the subcarrier that disposes between the user need to be responsive to the interference in the subcarrier, so time delay can be larger.

Configuration-the specific embodiment 11 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the kind of customer flow.For example: if customer flow is unicast traffic or multicast traffic, then time delay can be little or large according to conditioned disjunction situation change setting.But, if customer flow is broadcast traffic, then because be transferred to suitable a large number of users, so time delay is larger.

Configuration-the specific embodiment 12 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the quantity of MS in the Serving cell.For example: if a large amount of MS belongs to a residential quarter, then time delay can be set as higher value, and if a small amount of MS belong to a residential quarter, then time delay can be set as smaller value.

Configuration-the specific embodiment 13 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the conditioned disjunction state of residential quarter.For example: isolated residential quarter (for example focus) or many residential quarters can be divided in the residential quarter, and in isolated residential quarter, time delay can be set as little value, and time delay then is set as large value in many residential quarters.

Configuration-the specific embodiment 14 of time delay and/or unitary matrice

Come the respectively time delay of GP configuring SD according to the granule size that transmits in cps or chronomere.For example: if frequency granularity is meticulous (for example fine granulation), then because must consider the data degradation that interference causes, so time delay can be set as higher value.But, if frequency granularity is coarse (for example coarse granularity), then time delay is set as smaller value.Further, the logic OR rule identical with frequency granularity can be applied to time granularity.

Configuration-the specific embodiment 15 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the size of code book.For example: if system uses the code book with a small amount of pre-coding matrix, then time delay can be set as higher value, and if code book has a large amount of pre-coding matrixes, then time delay can be set as smaller value.

Configuration-the specific embodiment 16 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the quantity of transmitting antenna.For example: because the time delay of each antenna all must be distributed in fixedly in life span (Time-to-live, the TTL) cycle, so in having the system of a large amount of transmitting antennas the time-delay value of configuration less.For same cause, but from relative viewpoint, if number of transmission antennas is few, then time delay is set as higher value.

Configuration-the specific embodiment 17 of time delay and/or unitary matrice

The time delay of GPSD can be carried out different configurations according to the channel quality information that sends from MS.For example: but the receiver measure channel quality, and calculate modulation and encoding law (Modulation and Coding Scheme, MCS) level index according to the channel quality of measuring.After this, MCS level index can feed back (or transmission) to BS.As, if MCS level index is high, this indicates acceptable channel quality, then time delay is set as smaller value.

Execution is based on the emittor/receiver of the precoding of phase shift

Fig. 7 is for illustrating that use is based on the SCW OFDM type transmitter of the precoding of phase shift and the exemplary plot of receiver.Fig. 8 is for illustrating that use is based on the MCW OFDM type transmitter of the precoding of phase shift and the exemplary plot of receiver.

Generally speaking, communication system comprises transmitter and receiver.The device of carrying transmitter and receiver function can be described as transceiver.In other words, transceiver is the combination of transmitter and receiver.But, for the feedback information function is described really, so transmitter and receiver will separately be discussed.

Inside at downlink side, transmitter can be the part of BS, and receiver can be the part of MS.In addition, transmitter can be the part of MS, and receiver can be the part of BS.BS can comprise a plurality of transmitters and/or receiver.Similarly, MS can comprise a plurality of transmitters and/or receiver.

The function of receiver relative with the function of transmitter (or opposite), and carry out with reverse order.So, following discussion will be concentrated the function of explanation transmitter.

See also Fig. 7 and Fig. 8, transmitter comprises channel encoder (510,610), interleaver (520,620), inverse fast fourier transform (Inverse Fast Fourier Transform, IFFT) (550,650) and analog converter (560,660), add the assembly of explanation in Fig. 1.Because function has been consulted Fig. 1 and has been explained, so the discussion of these functions will be omitted.At this, will explain in detail the discussion of precoder (540,640).

Precoder (540,640) further comprises pre-coding matrix determination module (541,641) and precoding module (542,642).Especially, pre-coding matrix determination module (541,641) can be used for determining formula 12,14,15, the interior pre-coding matrix based on phase shift of 20 and 21 arbitrary forms.The above had discussed the details of how to confirm pre-coding matrix, therefore will omit further and discuss.Further, can determine pre-coding matrix determination module (541,641) according to phase shift relation configuration specific embodiment 1-3.

In addition, utilize the OFDM symbol with corresponding subcarrier to be multiplied by according to the determined pre-coding matrix based on phase shift of pre-coding matrix determination module (541,641), then precoding module (542,642) can be used for carrying out pre-encode operation.

Those skilled in the art may appreciate that in the present invention to have various modifications and variation, and do not deviate from spirit of the present invention and scope.Therefore, wish that the present invention contains these modifications of the present invention and variation, as long as it is in claims and the equivalent regions thereof.

Claims (6)

1. method of in using the multiaerial system of a plurality of subcarriers, using the precoding based on phase shift to be transmitted to receiver by transmitter, described method comprises:

To be defined as from the pre-coding matrix P of the first code book the first based on the pre-coding matrix of phase shift;

Determine diagonal matrix D to provide different phase angles to each of described a plurality of antennas, described diagonal matrix D can see the second portion based on the pre-coding matrix of phase shift as;

Select unitary matrice U conduct based on the third part of the pre-coding matrix of phase shift;

According to the described pre-coding matrix based on phase shift that is produced as P*D*U, come the relevant symbol of subcarrier is carried out precoding, described P*D*U is represented as:

And, send the described signal that uses described symbol and produce,

Wherein, P _{Nt * R}Represent described pre-coding matrix P, N _tThe number of expression transmitting antenna, U _{R * R}Represent described unitary matrice U, k represents the index relevant with described subcarrier, θ _iThe expression phase angle, i=1 ..., R, and R representation space reusability,

Wherein, the described phase angle θ of described diagonal matrix D _iIndex according to " i " increases linearly.

2. the method for claim 1, wherein from the described unitary matrice of the second codebook selecting.

3. the method for claim 1, wherein can differently be determined according to reusability corresponding to the time delay at the phase angle of described diagonal matrix.

4. use in having the multiaerial system of a plurality of subcarriers based on the precoding of phase shift signal is transmitted into the equipment of receiver for one kind, described equipment comprises:

The pre-coding matrix determination module, it is configured to the pre-coding matrix P from the first code book is defined as first based on the pre-coding matrix of phase shift; Determine diagonal matrix D to provide different phase angles to each of described a plurality of antennas, described diagonal matrix D can be looked at as the second portion based on the pre-coding matrix of phase shift; Select unitary matrice U conduct based on the third part of the pre-coding matrix of phase shift; And produce described pre-coding matrix P*D*U based on phase shift, described P*D*U is represented as:

P wherein _{Nt * R}Expression pre-coding matrix P, N _tThe number of expression transmitting antenna, U _{R * R}Expression unitary matrice U, k represents the index relevant with described subcarrier, θ _iThe expression phase angle, i=1 ..., R, and R representation space reusability;

Precoding module, it is configured to come the symbol of corresponding subcarrier is carried out precoding according to described pre-coding matrix based on phase shift, wherein, the described phase angle θ of described diagonal matrix D _iIndex according to " i " increases linearly, and

A plurality of antennas are configured to send the described signal that uses described symbol and produce.

5. equipment as claimed in claim 4, wherein, described pre-coding matrix determination module is from the described unitary matrice of the second codebook selecting.

6. equipment as claimed in claim 4 wherein, can differently be determined according to reusability corresponding to the time delay at the phase angle of described diagonal matrix.

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