CN100389544C - Circulating space-time block code transmitting and diversity project in CDMA system - Google Patents

Abstract

Transmitting diversity based on space-time codes has spatial and time diversity gain and can also obtain code gain. The coding of space-time block codes is simpler. But for plural signals, when the number of transmitting antennae is larger than two, coding efficiency is not high. Moreover, the project of the transmitting diversity of the space-time block codes is only suitable for quasistatic fading channels. A circulating space-time block code transmitting and diversity project in CDMA systems adopts a circulating space-time block coding method and different transmitting antennae adopt different orthogonal spread spectrum codes to make equivalent broad sense channel matrixes have orthogonality. Consequently, the coding is simple like traditional space-time block codes. After a receiving end deblocks receiving signals, only a plurality of simple linear operations are required for coding code words for effectively resisting the fade of channels. Consequently, systemic transmitting performance is enhanced.

Description

Circulating space-time block code transmitting and diversity project in the code division multiple access system

Technical field

The present invention is a solution of space-time emission diversity in MIMO CDMA (the Duo Shuruduoshuchu code division multiple access) system.Be mainly used in the problem that solves the not high and antagonism rapid fading multipath channel of code efficiency when adopting traditional space-time block code transmitting and diversity method in the MIMO cdma system, belong to MIMO cdma system space-time emission diversity technical field.

Background technology

How many unfavorable factors such as change overcame this unfavorable factor when wireless channel environment existed multipath fading, Doppler frequency shift and channel quick, were that mobile communication needs the problem studied all the time.At present, for guaranteeing the reliable transmission of wireless channel, proposed a lot of technology, verified from information-theoretical angle, MIMO (multiple-input and multiple-output) technology can increase the capacity of wireless communication system greatly, improves the performance of wireless communication system.The MIMO technology is the important breakthrough in wireless mobile communications field, it utilizes the transmission channel that increases in the space, adopt many antennas at transmitting terminal and receiving terminal, because the signal that each transmitting antenna sends simultaneously takies same frequency band, so do not increase bandwidth, thereby can improve the capacity and the availability of frequency spectrum of system greatly.

The MIMO technology of broad sense relates to extensively, mainly comprises transmit diversity techniques and space multiplexing technique.Wherein space multiplexing technique is the different information of emission on different antennas, and the V-BLAST sign indicating number of Bell Laboratory is that the typical case of space multiplexing technique uses; And transmit diversity techniques is that emission comprises the signal of same information on different antennas, thereby reaches the effect of space diversity., can overcome channel fading largely, improve systematic function, thereby receive much concern because transmit diversity on the spatial domain and the coding on the time-domain are combined based on the Space Time Coding technology of transmit diversity.

Space Time Coding (Space-Time-Coding) technology is a technology based on transmit diversity that was proposed by people such as Tarokh in 1998.People such as Tarokh think, if adopt the coding techniques that is fit to many antenna transmission at transmitting terminal, carry out the corresponding signal process technology at receiving terminal simultaneously, can obtain very big performance gain.Information theory studies show that, suppose that multiaerial system has M transmit antennas and N root reception antenna, and hypothesis is under the channel of arrowband slow fading, just can set up the matrix of M * N rank reflection channel characteristics, its element is independent identically distributed Gaussian random variable, and like this, the obtainable channel capacity of system will exceed min (M than single antenna, N) doubly, and total transmitting power remains unchanged.Yet, because the prompting message of fading channel is difficult to seizure, therefore, transmitting terminal must adopt channel coding technology, guaranteeing under most channel situation to obtain reasonable performance, this chnnel coding be in essence in time with the space on the bidimensional coding, Space Time Coding just.

Space Time Coding based on transmit diversity mainly contains two kinds: Space-Time Block Coding (STBC, Space Time BlockCode) and space-time trellis codes (STTC, Space Time Trellis Code).Space-time trellis codes is that people such as Tarokh proposed in 1998, space-time trellis codes combines coding, modulation, transmit diversity, can obtain diversity gain and coding gain simultaneously, and make the performance of system improve a lot, but, because it adopts the Viterbi decoding based on Euclidean distance, so decoding complexity is higher, and decoding complexity will be the index increase along with the increase of transmission rate.And Space-Time Block Coding is that Alamouti was proposition in 1998, Space-Time Block Coding is to launch from two antennas behind the same information via orthogonal coding, two paths of signals only need do simple linear the merging just can obtain gain owing to have orthogonality at receiving terminal.Space-Time Block Coding has been because its simple structure and good performance have obtained extensive studies, and entered 3GPP very soon.But, also there is certain problem in the structure of Space-Time Block Coding, for complex signal, be that 1 code character is still waiting more deep research when whether the emission fate exists code rate greater than 2 the time, and space-time block code transmitting and diversity project only is applicable to the quasistatic fading channel.

Summary of the invention

Technical problem: the objective of the invention is in the MIMO cdma system, to provide the circulating space-time block code transmitting and diversity project in a kind of code division multiple access system, be used for solving traditional space-time block code transmitting and diversity when emission fate not high shortcoming of code efficiency greater than 2 time, and can resist the rapid fading multipath channel effectively.

Technical scheme: technical characterictic of the present invention is exactly the coding and decoding and the launching technique of circulating space-time block code.

One of design criterion of Space-Time Block Coding is an orthogonal design, and promptly the Space-Time Block Coding matrix satisfies orthogonality, still,, does not also have such sign indicating number battle array to satisfy orthogonality condition at present and makes that code efficiency is 1 greater than 2 o'clock for complex signal and number of transmit antennas; In addition, the decoding of Space-Time Block Coding has individual restrictive condition, and that is exactly under quasi-static channel opens, and promptly channel is constant in a code character, and this is difficult to satisfy in actual applications.

Circulating space-time block code in this programme is that input information symbol (supposing that every group has M the code word) loop coding that divides into groups is become a symmetric code battle array (M * M ties up matrix), the code word of different rows adopts different orthogonal intersections to carry out launching (corresponding M the spreading code of M root antenna) by corresponding antenna behind the spread spectrum respectively in the symmetric code battle array, that is: the corresponding transmitting antenna of row in the sign indicating number battle array, the corresponding orthogonal intersection of every transmit antennas.Since the circulating space-time group coding, and at the different different spreading codes of transmitting antenna employing, this equals to have given orthogonal property to institute's channel transmitted, and promptly Deng Xiao generalized channel matrix is an orthogonal matrix.During decoding, at first collect all information in the code character time cycle, the spread spectrum code character that is adopted when the information that is received in each symbol period in the code character is all used emission (M spreading code altogether) is carried out despreading, like this, the information of interior all symbol periods of code character is formed a sign indicating number battle array (the despreading information in respective symbol cycle is listed as accordingly corresponding to matrix) after despreading, just in time opposite during with coding, circulate the information matrix after the despreading is counter respectively, utilize channel parameter just can translate code word again.This programme is fit to input signal arbitrarily, and also is not limited to quasi-static channel opens during decoding.

Circulating space-time block code transmitting and diversity project in the code division multiple access system of the present invention is to adopt circulating space-time group coding and decoding method, and adopt different orthogonal intersections at different transmitting antennas, make the generalized channel matrix of equivalence have orthogonality, thereby make decoding the same simple with traditional Space-Time Block Coding, only need do some simple linear operations after the receiving terminal despreading to received signal and can translate code word, concrete step is; At transmitting terminal the M transmit antennas is arranged:

1), at first input information is divided into groups, every group contains M information symbol is b ₁, b ₂... b _M, use b _mRepresent m information symbol, m is integer and 1≤m≤M,

2), this M information symbol formed a M * M dimension sign indicating number battle array,

$B_M=\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2...b_m...{\mathrm{<figure-callout\; id="1"\; label="b\; M\; b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_M& \\ b_{}{}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2...b_m...b_M\\ ....................\\ {\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2...b_m...b_M\end{array}\right]$

3), successively capable all information symbols of m in the sign indicating number battle array are circulated left and move the m-1 position to finish loop coding m be integer and 1≤m≤M,

4), all capable information symbols of m in the sign indicating number battle array behind the loop coding be multiply by a spread spectrum codes C _mLaunch from m root antenna the back, wherein, and C _mRepresent m spreading code,

At receiving terminal N root reception antenna number is arranged:

21), at first collect first the reception information to M symbol period,

22), M spreading code being adopted when all multiply by emission respectively of information that each symbol period is received carry out despreading, that is: to the received signal r of each symbol period _{N, m}Use C respectively ₁, C ₂C _MCarry out despreading, wherein, n represents n root reception antenna,

23), the despreading information of M symbol period is formed a sign indicating number battle array,

$R_{n,d}=\left[\begin{array}{ccccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,\mathrm{<figure-callout\; id="2"\; label="n\; b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">n</figure-callout>}}{b}_{}{}_2& ........& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{\mathrm{<figure-callout\; id="1"\; label="b\; m\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_m& h_{}{}_{1,n}{\mathrm{<figure-callout\; id="2"\; label="b\; M\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_M& \\ h_{}{}_{2,n}{b}_2& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3& ........& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{\mathrm{<figure-callout\; id="2"\; label="b\; M\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_M& h_{}{}_{2,\mathrm{<figure-callout\; id="1"\; label="n\; b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">n</figure-callout>}}{b}_{}{}_1\\ ........& .........& ........& ........& ........\\ h_{m,n}{b}_m& h_{m,n}{b}_{m+1}& ........& h_{m,n}{b}_{m-2}& h_{m,n}{b}_{m-1}\\ ........& ........& ........& ........& ........\\ h_{M,n}{b}_M& h_{M,\mathrm{<figure-callout\; id="1"\; label="n\; b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">n</figure-callout>}}{b}_{}{}_1& ........& h_{M,n}{b}_{M-2}& h_{M,n}{b}_{M-1}\end{array}\right]+{\mathrm{\&psi;}}_n$

H wherein _{M, n}Represent that the m transmit antennas is to the channel parameter between n root reception antenna, ψ _nRepresent the white Gaussian noise matrix on the n root reception antenna, n=1～N; D represents despreading,

24), just in time opposite with when coding, respectively with the information matrix R after the despreading _{N, d}Capable the circulation to the right of m move the m-1 position, the matrix D of getting back like this _{N, d},

25), utilize channel information to carry out linearity to merge,

26), sue for peace after the information on all reception antennas done same processing,

27), at last the information of summation is adjudicated recovery emission information.

Beneficial effect: use this programme that following advantage is arranged:

Circulating space-time block code transmitting and diversity based on the MIMO cdma system in this programme has overcome the transmit diversity code efficiency not high shortcoming of emission fate greater than 2 o'clock employing Space-Time Block Codings, and can resist the rapid fading multipath channel effectively.This programme adopts the circulating space-time group coding, and adopt different orthogonal intersections at different transmitting antennas, make the generalized channel matrix of equivalence have orthogonality, therefore its decoding is the same simple with traditional Space-Time Block Coding, only need do some simple linear operations after the receiving terminal despreading to received signal, can translate code word.

1, overcome in the space-time block code transmitting and diversity project for complex signal when number of transmit antennas not high shortcoming of code efficiency greater than 2 time, and this programme is applicable to any signal and number of transmit antennas arbitrarily.

2, this programme can resist the rapid fading multipath channel effectively, and space-time block code transmitting and diversity project only is applicable to the quasistatic fading channel.

Description of drawings

Fig. 1 be space-time block code transmitting and diversity project and circulating space-time block code transmitting and diversity project under the fading channel environment of single footpath error performance relatively.

Fig. 2 be space-time block code transmitting and diversity project and circulating space-time block code transmitting and diversity project under four footpath fading channel environment error performance relatively.

Fig. 3 is the flow chart when transmitting terminal has the M transmit antennas.

Fig. 4 is the flow chart when receiving terminal has N root reception antenna.

Among the figure, STBC represents space-time block code transmitting and diversity project; C-STBC represents circulating space-time block code transmitting and diversity project.

Embodiment

Circulating space-time block code (C-STBC) coding and decoding method

For the MIMO cdma system with M transmit antennas, N root reception antenna, the input information symbol at first is grouped, and every group contains M symbol (b _M=[b ₁, b ₂..b _m..b _M]), b wherein _MExpression information symbol vector, b _mThe expression information symbol.With this M symbol loop coding is M * M dimension sign indicating number battle array B _M, the specific coding method is: B _MM capable be with b _MCirculation left moves the symbol that the m-1 position obtains.For convenience of explanation, with M=4 be the coding and decoding method of example explanation circulating space-time block code.b ₄=[b ₁, b ₂, b ₃, b ₄], the loop coding matrix B ₄For

$B_4=\left[\begin{array}{cccc}{b}_1& b_2& b_3& b_4\\ b_2& b_3& b_4& b_1\\ b_3& b_4& b_1& b_2\\ b_4& b_1& b_2& b_3\end{array}\right]---\left(1\right)$

As can be seen, the loop coding matrix is symmetrical matrix, i.e. a B ₄=B ₄ ^TBehind the loop coding, B ₄4 row symbols in 4 symbol periods, launch after adopting 4 different spreading code spread spectrums respectively corresponding to 4 transmit antennas.Loop coding matrix behind the spread spectrum is

$T_4=\left[\begin{array}{cccc}{b}_1{c}_1& b_2{c}_1& b_3{c}_1& b_4{c}_1\\ b_2{c}_2& b_3{c}_2& b_4{c}_2& b_1{c}_2\\ b_3{c}_3& b_4{c}_3& b_1{c}_3& b_2{c}_3\\ b_4{c}_4& b_1{c}_4& b_2{c}_4& b_3{c}_4\end{array}\right]---\left(2\right)$

Wherein $c_m=1/\sqrt{Q}[c_{m,1},c_{m,2}...c_{m,q}...c_{m,Q}]$ Represent the spreading code on the m root antenna, c _{M, q}=± 1, Q is a spreading gain.Suppose each transmitting antenna at a distance of enough far away, promptly each transmitting antenna is independent to the channel between reception antenna, and the hypothesis channel is a flat fading channel.If h _{4, n}=[h _{1, n}, h _{2, n}, h _{3, n}, h _{4, n}] ^TBe the channel parameter vector of this 4 transmit antennas to n root reception antenna, wherein h _{M, n}Represent the m transmit antennas to the channel parameter between n root reception antenna, then the received signal in 4 symbol periods on the n root reception antenna can be expressed as (assumes synchronization mechanism improve and do not have ISI and ICI)

$R_n=h_{4,n}^T{T}_4+{\mathrm{\&xi;}}_n={\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2{c}_2^T+h_{3,n}{b}_3{c}_3^T+h_{4,n}{b}_4{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_2{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3{c}_2^T+h_{3,n}{b}_4{c}_3^T+h_{4,n}{b}_1{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_3{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4{c}_2^T+h_{3,n}{b}_1{c}_3^T+h_{4,n}{b}_2{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_4{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1{c}_2^T+h_{3,n}{b}_2{c}_3^T+h_{4,n}{b}_3{c}_4^T\end{array}\right]}^T+{\mathrm{\&xi;}}_n---\left(3\right)$

$=[r_{n,1},r_{n,2},r_{n,3},r_{n,4}]+{\mathrm{\&xi;}}_n$

ξ wherein _nBe that variance is σ ²The white Gaussian noise vector of I, r _{N, m}Represent r _{N, 1}, r _{N, 2}, r _{N, 3}, r _{N, 4}One of in, representing the received signal of m symbol period of n root reception antenna, T represents transposition.Received signal r to each symbol period _{N, m}Use C respectively ₁, C ₂... C ₄Carry out despreading.Like this, the despread signal of 4 symbol periods can be formed a matrix R _{N, d}

$R_{n,d}=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_3& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_4\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1\\ h_{3,n}{b}_3& h_{3,n}{b}_4& h_{3,n}{b}_1& h_{3,n}{b}_2\\ h_{4,n}{b}_4& h_{4,n}{b}_1& h_{4,n}{b}_2& h_{4,n}{b}_3\end{array}\right]+{\mathrm{\&psi;}}_n---\left(4\right)$

R wherein _{N, d}In the element of each row be respectively to use r _{N, m}With C ₁, C ₂... C ₄Carry out the result of despreading, ψ _nBe 4 * 4 dimension white Gaussian noise matrixes.Just in time opposite during with coding, respectively with the information matrix R after the despreading _{N, d}Capable the circulation to the right of m move the m-1 position, the matrix D of getting back like this _{N, d}

$D_{n,d}=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_3& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_4\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4\\ h_{3,n}{b}_1& h_{3,n}{b}_2& h_{3,n}{b}_3& h_{3,n}{b}_4\\ h_{4,n}{b}_1& h_{4,n}{b}_2& h_{4,n}{b}_3& h_{4,n}{b}_4\end{array}\right]+{\mathrm{\&psi;}}_n^{\&prime;}---\left(5\right)$

ψ ' wherein _nBe ψ _nCyclic shift matrices.Suppose channel parameter vector h _{4, n}=[h _{1, n}, h _{2, n}, h _{3, n}, h _{4, n}] ^TEstimate, then former emission information can draw from following formula

${\hat{b}}_4=\mathrm{Dec}\left(h_{4,n}^H{D}_{n,d}\right)=\mathrm{Dec}\left(\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2\right[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+h_{4,n}^H{\mathrm{\&psi;}}_n^{\&prime;})---\left(6\right)$

Wherein Dec (.) expression judgement computing,

Expression b ₄Estimation, H represents conjugate transpose.For N root reception antenna, then

${\hat{b}}_4=\mathrm{Dec}\left(\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{D}_{n,d}\right)=\mathrm{Dec}\left(\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2\right[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{\mathrm{\&psi;}}_n^{\&prime;})---\left(7\right)$

More than provided the concrete grammar of code coding/decoding when circulation is empty.The another kind that can draw the empty time-code of circulation from formula (3) is represented mode.

$R_n=h_{4,n}^T{T}_4+{\mathrm{\&xi;}}_n={\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2{c}_2^T+h_{3,n}{b}_3{c}_3^T+h_{4,n}{b}_4{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_2{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3{c}_2^T+h_{3,n}{b}_4{c}_3^T+h_{4,n}{b}_1{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_3{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4{c}_2^T+h_{3,n}{b}_1{c}_3^T+h_{4,n}{b}_2{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_4{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1{c}_2^T+h_{3,n}{b}_2{c}_2^T+h_{4,n}{b}_3{c}_4^T\end{array}\right]}^T+{\mathrm{\&xi;}}_n$

$=[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{c}_1& h_{4,n}{c}_4& h_{3,n}{c}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{c}_2\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{c}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{c}_1& h_{4,n}{c}_4& h_{3,n}{c}_3\\ h_{3,n}{c}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{c}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{c}_1& h_{4,n}{c}_4\\ h_{4,n}{c}_4& h_{3,n}{c}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{c}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,\mathrm{<figure-callout\; id="1"\; label="n\; c"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">n</figure-callout>}}{c}_{}{}_1\end{array}\right]+{\mathrm{\&xi;}}_n---\left(8\right)$

$=b_4{F}_{4,n}^H+{\mathrm{\&xi;}}_n$

Wherein

$F_{4,n}=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}^{*}{c}_1^{\mathrm{<figure-callout\; id="2"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{2,n}^{*}{c}_2^T& h_{3,n}^{*}{c}_3^T& h_{4,n}^{*}{c}_4^T\\ h_{4,n}^{*}{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{1,n}^{*}{c}_1^{\mathrm{<figure-callout\; id="2"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{2,n}^{*}{c}_2^T& h_{3,n}^{*}{c}_3^T\\ h_{3,n}^{*}{c}_3^T& h_{4,n}^{*}{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{1,n}^{*}{c}_1^{\mathrm{<figure-callout\; id="2"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{2,n}^{*}{c}_2^{\mathrm{<figure-callout\; id="2"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}^{}{}_{2,n}^{*}{c}_2^T& h_{3,n}^{*}{c}_3^T& h_{4,n}^{*}{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& h_{}^{}{}_{1,n}^{*}{c}_1^T\end{array}\right]---\left(9\right)$

Because the circulating space-time group coding, and at the different different spreading codes of transmitting antenna employing, this equals to have given orthogonal property to institute's channel transmitted, i.e. Deng Xiao generalized channel matrix F _{4, n}Be orthogonal matrix, promptly

$F_{4,n}^H{F}_{4,n}=\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^{2}I---\left(10\right)$

So

${\hat{b}}_4=\mathrm{Dec}\left(R_n{F}_{4,n}\right)=\mathrm{Dec}\left(\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2\right[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+{\mathrm{\&xi;}}_n{F}_{4,n})---\left(11\right)$

Circulating space-time block code and Space-Time Block Coding send the comparison of code word in the MIMO cdma system

Table 1 has provided circulating space-time block code transmitting and diversity project (C-STBC) and space-time block code transmitting and diversity project (STBC) send signal in two symbol periods comparison (number of transmit antennas M=2).

Table 1

Emulation relatively

Space-time block code transmitting and diversity project and circulating space-time block code transmitting and diversity project are carried out emulation relatively in the same environment under the MIMO cdma system.Suppose number of users K=4, information source is the 2PSK signal, spreading code adopts 32 Walsh sign indicating numbers, multiple access disturbs MAI=10dB, channel adopts single footpath rayleigh fading channel and four footpath rayleigh fading channels respectively, four footpaths are during rayleigh fading channel, and each footpath postpones to differ a chip period and each footpath amplitude of fading differs 4dB.

Simulation result is (error rate obtains after 5000 symbols of reception are averaged among the figure) as depicted in figs. 1 and 2.

Fig. 1 be under the fading channel environment of single footpath error performance relatively, as can be seen from the figure, no matter be two one receive or two two receipts situations under, the error performance of two kinds of schemes is more approaching.Fig. 2 is that the error performance under four footpath fading channel environment compares, as can be seen from the figure, no matter be two one receive or two two receipts situations under, circulating, all the error performance than space-time block code transmitting and diversity project is good for empty time-code emission diversity scheme, and the empty time-code emission diversity scheme anti-multipath decline of this explanation circulation ability is strong.

Concrete implementation step:

One, transmitting terminal (supposing to have the M transmit antennas)

1, at first input information is divided into groups, every group contains M symbol (b _M=[b ₁, b ₂..b _m..b _m]).

2, this M information symbol formed a M * M dimension sign indicating number battle array (is example with 4 antennas),

$\left[\begin{array}{cccc}{b}_1& b_2& b_3& b_4\\ b_1& b_2& b_3& b_4\\ b_1& b_2& b_3& b_4\\ b_1& b_2& b_3& b_4\end{array}\right]$

3, successively the capable information symbol of m in the sign indicating number battle array is circulated left and move the m-1 position and finish loop coding

$B_4=\left[\begin{array}{cccc}{b}_1& b_2& b_3& b_4\\ b_2& b_3& b_4& b_1\\ b_3& b_4& b_1& b_2\\ b_4& b_1& b_2& b_3\end{array}\right]$

4, will encode and launch from corresponding antenna after the information symbol of corresponding line multiply by a spreading code in the cyclic code battle array of back, the loop coding matrix behind the spread spectrum is

$T_4=\left[\begin{array}{cccc}{b}_1{c}_1& b_2{c}_1& b_3{c}_1& b_4{c}_1\\ b_2{c}_2& b_3{c}_2& b_4{c}_2& b_1{c}_2\\ b_3{c}_3& b_4{c}_3& b_1{c}_3& b_2{c}_3\\ b_4{c}_4& b_1{c}_4& b_2{c}_4& b_3{c}_4\end{array}\right]$

Wherein $c_m=1/\sqrt{Q}[c_{m,1},c_{m,2}...c_{m,q}...c_{m,Q}]$ Represent the spreading code on the m root antenna, c _{M, q}=± 1, Q is a spreading gain.

Two, receiving terminal (N is the reception antenna number, is example with 4 transmit antennas still)

1, at first collects the reception information of M symbol period.Suppose h _{4, n}=[h _{1, n}, h _{2, n}, h _{3, n}, h _{4, n}] ^TBe the channel parameter vector of this 4 transmit antennas to n root reception antenna, wherein h _{M, n}Represent the m transmit antennas to the channel parameter between n root reception antenna, then the received signal in 4 symbol periods on the n root reception antenna can be expressed as (assumes synchronization mechanism improve and do not have ISI and ICI)

$R_n=h_{4,n}^T{T}_4+{\mathrm{\&xi;}}_n={\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2{c}_2^T+h_{3,n}{b}_3{c}_3^T+h_{4,n}{b}_4{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_2{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3{c}_2^T+h_{3,n}{b}_4{c}_3^T+h_{4,n}{b}_1{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_3{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4{c}_2^T+h_{3,n}{b}_1{c}_3^T+h_{4,n}{b}_2{c}_4^{\mathrm{<figure-callout\; id="1"\; label="T\; h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">T</figure-callout>}}& \\ h_{}{}_{1,n}{b}_4{c}_1^T+{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1{c}_2^T+h_{3,n}{b}_2{c}_3^T+h_{4,n}{b}_3{c}_4^T\end{array}\right]}^T+{\mathrm{\&xi;}}_n$

$=[r_{n,1},r_{n,2},r_{n,3},r_{n,4}]+{\mathrm{\&xi;}}_n$

ξ wherein _nBe that variance is σ ²The white Gaussian noise vector of I, r _{N, m}Represent r _{N, 1}, r _{N, 2}, r _{N, 3}, r _{N, 4}One of in, represent the received signal of m symbol period of n root reception antenna.

M the spreading code that is adopted when 2, the information that each symbol period is received all multiply by emission respectively carries out despreading, that is: to the received signal r of each symbol period _{N, m}Use C respectively ₁, C ₂, C ₃, C ₄Carry out despreading.

3, the despreading information of M symbol period is formed a sign indicating number battle array.That is: the despread signal of 4 symbol periods can be formed a matrix R _{N, d}

$R_{n,d}=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_3& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_4\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1\\ h_{3,n}{b}_3& h_{3,n}{b}_4& h_{3,n}{b}_1& h_{3,n}{b}_2\\ h_{4,n}{b}_4& h_{4,n}{b}_1& h_{4,n}{b}_2& h_{4,n}{b}_3\end{array}\right]+{\mathrm{\&psi;}}_n$

R wherein _{N, d}In the element of each row be respectively to use r _{N, m}With c ₁, c ₂, c ₃, c ₄Carry out the result of despreading, ψ _nBe 4 * 4 dimension white Gaussian noise matrixes.

Just in time opposite during 4, with coding, respectively with the information matrix R after the despreading _{N, d}Capable the circulation to the right of m move the m-1 position, the matrix D of getting back like this _{N, d}

$D_{n,d}=\left[\begin{array}{cccc}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_1& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_2& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_3& {\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,n}{b}_4\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_1& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_2& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_3& {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,n}{b}_4\\ h_{3,n}{b}_1& h_{3,n}{b}_2& h_{3,n}{b}_3& h_{3,n}{b}_4\\ h_{4,n}{b}_1& h_{4,n}{b}_2& h_{4,n}{b}_3& h_{4,n}{b}_4\end{array}\right]+{\mathrm{\&psi;}}_n^{\&prime;}$

ψ ' wherein _nBe ψ _nCyclic shift matrices.

5, utilize channel information to carry out linearity and merge,

$h_{4,n}^H{D}_{n,d}=\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+h_{4,n}^H{\mathrm{\&psi;}}_n^{\&prime;}$

6, after being done same processing, the information on all reception antennas sues for peace

$\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{D}_{n,d}=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{\mathrm{\&psi;}}_n^{\&prime;}$

7, at last the information of summation is adjudicated, recover emission information

${\hat{b}}_4=\mathrm{Dec}\left(\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{D}_{n,d}\right)=\mathrm{Dec}\left(\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{m=1}{\overset{4}{\mathrm{\&Sigma;}}}{\left|h_{m,n}\right|}^2\right[{\mathrm{<figure-callout\; id="1"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_1,{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="C20051009538900142.png"\; state="\{\{state\}\}">b</figure-callout>}}_2,b_3,b_4]+\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{h}_{4,n}^H{\mathrm{\&psi;}}_n^{\&prime;})$

Wherein Dec (.) expression judgement computing.

Claims (1)

1. the circulating space-time block code transmitting and diversity method in the code division multiple access system, it is characterized in that adopting circulating space-time group coding and decoding method, and adopt different orthogonal intersections at different transmitting antennas, make the generalized channel matrix of equivalence have orthogonality, thereby make decoding the same simple with traditional Space-Time Block Coding, only need do some simple linear operations after the receiving terminal despreading to received signal and can translate code word, concrete step is;

At transmitting terminal the M transmit antennas is arranged:

1), at first input information is divided into groups, every group contains M information symbol is b ₁, b ₂... b _M, use b _mRepresent m information symbol, m is integer and 1≤m≤M,

2), this M information symbol formed a M * M dimension sign indicating number battle array,

$B_M=\left[\begin{array}{c}{b}_1,b_2...b_m...b_M\\ b_1,b_2...b_m...b_M\\ ....................\\ b_1,b_2...b_m...b_M\end{array}\right]$

3), successively capable all information symbols of m in the sign indicating number battle array are circulated left and move the m-1 position and finish loop coding,

4), all capable information symbols of m in the sign indicating number battle array behind the loop coding be multiply by a spread spectrum codes C _mLaunch from m root antenna the back, wherein, and C _mRepresent m spreading code,

At receiving terminal N root reception antenna number is arranged:

21), at first collect first the reception information to M symbol period,

22), M spreading code being adopted when all multiply by emission respectively of information that each symbol period is received carry out despreading, that is: to the received signal r of each symbol period _{N, m}Use C respectively ₁, C ₂C _MCarry out despreading, wherein, n represents n root reception antenna,

23), the despreading information of M symbol period is formed a sign indicating number battle array,

$R_{n,d}=\left[\begin{array}{ccccc}{h}_{1,n}{b}_1& h_{1,n}{b}_2& ........& h_{1,n}{b}_m& h_{1,n}{b}_M\\ h_{2,n}{b}_2& h_{2,n}{b}_3& ........& h_{2,n}{b}_M& h_{2,n}{b}_1\\ ........& ........& ........& ........& ........\\ h_{m,n}{b}_m& h_{m,n}{b}_{m+1}& ........& h_{m,n}{b}_{m-2}& h_{m,n}{b}_{m-1}\\ ........& ........& ........& ........& ........\\ h_{M,n}{b}_M& h_{M,n}{b}_1& ........& h_{M,n}{b}_{M-2}& h_{M,n}{b}_{M-1}\end{array}\right]+{\mathrm{\&psi;}}_n$

H wherein _{M, n}Represent that the m transmit antennas is to the channel parameter between n root reception antenna, ψ _nRepresent the white Gaussian noise matrix on the n root reception antenna, n=1～N; D represents despreading,

24), just in time opposite with when coding, respectively with the information matrix R after the despreading _{N, d}Capable the circulation to the right of m move the m-1 position, the matrix D of getting back like this _{N, d},

25), utilize channel information to carry out linearity to merge,

26), sue for peace after the information on all reception antennas done same processing,

27), at last the information of summation is adjudicated recovery emission information.

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