CN1411190A - Vertical Bell laboratory ranked space and time code array linear detecting method - Google Patents

Abstract

A V-BLAST array linear detection method, comprising: setting initialization conditions in a memory after receiving an N-dimensional column vector; determining a weight value for linear decorrelation detection, and multiplying the weight value with the received column vector; Use the soft decision method for quantization to obtain the strongest signal in the received signal; remove the obtained strongest signal from the received column vector signal, and then detect it in the received signal after removing the strongest sub-data stream Among them, the strongest sub-data flow is removed as interference. In this way, all signals of the "strongest sub-data stream" are sequentially detected, and the detected signals are quantized to obtain the sub-data stream transmitted by the transmitter, which is the detected column vector. The received signal is quantified by the method of soft decision, in which the soft decision algorithm adopts the method of hyperbolic tangent nonlinear detection, which can detect the signal transmitted by the transmitter at the receiver more accurately, and improve the demodulation and coordination in the existing wireless communication system. The decoding precision.

Description

Vertical Bell Labs Layered Space-Time Coded Array Linear Detection Method

technical field

The present invention relates to a kind of array linear detection method in code division multiple access wireless system, especially relate to a kind of Vertical-Bell Laboratories Layered Space Time code (Vertical-Bell Laboratories Layered Space Time, hereinafter referred to as for short) in code division multiple access wireless system V-BLAST) array linear detection method.

Background technique

V-BLAST is a high-speed data transmission technology. It uses multi-element antennas at both the transmitting and receiving ends, and can achieve a transmission rate far exceeding the existing technology. Laboratory results show that when the average signal-to-noise ratio is 24-34dB, the transmission efficiency can reach 20-40bps/Hz (Bit Per Second/Hertz, bit per second per Hertz), which cannot be achieved by applying existing technologies.

The V-BLAST technology applies the propagation characteristics of the multipath environment, and regards the scattered multipath as parallel sub-data streams to enhance the accuracy of the transmission instead of reducing the accuracy of the transmission. The V-BLAST technology divides the user data stream into sub-data streams, and uses the array antenna to transmit parallel sub-data streams at the same time. All sub-data streams are transmitted in the same frequency band, so the spectrum efficiency is very high. Because user data is transmitted with multiple antennas in parallel, the effective transmission rate is proportional to the number of transmit antennas.

At the receiving end, an array antenna is also used to receive the transmitted signal and its scattered signal. Each receive antenna receives all sub-streams. If there is enough multipath scattering, the dispersion is different for each substream, and the transmit antennas for the substreams are spatially different. The difference in scatter of these sub-streams enables sub-streams to be identified and detected. In the process of linear decorrelation detection of sub-data streams, the strongest sub-data stream is detected first, and then the strongest sub-data stream is removed from the received signal as interference; then in the received signal after removing the strongest sub-data stream Then detect the strongest sub-data stream, and remove it as interference. In this way, all signals of the "strongest sub-data stream" are sequentially detected, and the detected signals are further quantized, which is the sub-data stream transmitted by the transmitter.

In V-BLAST technology, it is assumed that the channel transmission characteristics are unknown for the transmitting antenna and known for the receiving antenna, and the number of array elements of the receiving antenna is greater than or equal to the number of array elements of the transmitting antenna.

In the V-BLAST array detection receiver, the detected signal is also quantized to obtain a more accurate transmitted signal. For signals that have not undergone channel coding, the quantization process adopts a hard decision process, and the point with the closest Euclidean distance to the detected signal is used as the quantization value of the signal on the constellation diagram of the corresponding modulation method. For the channel-coded signal, if the hard-decision quantization method is used, the quantization error will be large, which will affect the decoding accuracy in the future, so the soft-decision method must be used for quantization.

Contents of the invention

In view of the shortcomings of the prior art, the purpose of the present invention is to provide an array linear detection method to more accurately detect the signal transmitted by the transmitter at the receiver.

To achieve the above object, the present invention provides a V-BLAST array linear detection method, wherein the transmitting side transmits the Symbol (symbol) M-dimensional column vector $\stackrel{\&Right\; Arrow;}{a}={(a_1,a_2,\&Center\; Dot;\&Center\; Dot;\&Center\; Dot;,a_m)}^T,$ The channel transfer matrix from the transmitter to the receiver is H ^N*M , where h _ij in H ^N*M is the transfer function from the transmitting array element j to the receiving array element i, M≤N, and the method includes:

a) Receive Symbol N-dimensional column vector $\stackrel{\&Right\; Arrow;}{r}={({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="A0113564200131.png"\; state="\{\{state\}\}">r</figure-callout>}}_1,r_2,\&CenterDot;\&Center\; Dot;\&Center\; Dot;,r_N)}^T;$

b) Set initialization conditions in the memory: i=1, G ₁ =H ⁺ , k ₁ =argmin _j ‖(G ₁ ) _j ‖ ² (G ₁ ) _j represents the jth row vector of G ₁ , k ₁ = argmin _j ‖(G ₁ ) _j ‖ ² means to find a vector with the smallest norm among the row vectors of G ₁ , and assign the row number (1, 2, 3...M) of this vector to k ₁ ;

c) Use the k _ith vector found as the weight ( ${\stackrel{\&Right\; Arrow;}{w}}_{k_i}={\left(G_i\right)}_{k_i}^T$ ), determine the weight of linear decorrelation detection And multiply the weight with the received Symbol column vector to get the k _ith Symbol( ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i$ );

d) Quantize the k _i th Symbol obtained using a soft decision method ( ), find the received signal The ith strongest signal in

(

)，得到将

中已经检测出的Symbol对应的列向量去除后的矩阵

e) Remove the strongest signal obtained in step d) from the received column vector signal

(

), get the

The matrix after removing the column vector corresponding to the Symbol that has been detected in

f) find out Pseudo-inverse of , ( $G_{i+1}=h_{k_i}^{\&PlusMinus;}$ );

g) Find a vector with the smallest norm among the row vectors of G _i+1 , and assign the row number (1, 2, 3...M) of this vector to k ₁ ( $k_{i+1}={\arg \min }_{j\&NotElement;\{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A0113564200131.png"\; state="\{\{state\}\}">k</figure-callout>}}_1,k_2,\&Center\; Dot;\&Center\; Dot;\&Center\; Dot;k_i\}}\left|\right|{\left(G_{i+1}\right)}_j|{|}^2$ )

h) If i<M, then i=i+1, return to step c);

...、

)即为所检测出的列向量。i) If i=M, then the M strongest signals obtained (

...,

) is the detected column vector.

In the above V-BLAST array linear detection method, wherein the soft decision method is a hyperbolic tangent quantization method.

The above-mentioned V-BLAST array linear detection method, wherein the emitting Symbol M-dimensional column vector of the emitting party $\stackrel{\&Right\; Arrow;}{a}={(a_1,a_2,\&Center\; Dot;\&Center\; Dot;\&CenterDot;,a_m)}^T$ It is a signal modulated by QPSK (Quadrature PhaseShift Keying) method.

The above-mentioned V-BLAST array linear detection method, wherein the hyperbolic tangent quantification method is:

in, ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i$ $={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T({\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)$ $=a_{k_i}+{\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T(\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)$ $\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v$ Is the interference and noise items, subject to Gaussian distribution, the variance is

The V-BLAST array detection receiver using linear decorrelation detection proposed by the present invention adopts the method of soft decision to quantize the received signal, wherein the soft decision algorithm adopts the method of hyperbolic tangent nonlinear detection, which can more accurately The signal transmitted by the transmitter is detected, and the accuracy of demodulation and decoding in the existing wireless communication system is improved.

Description of drawings

FIG. 1 is a diagram of the downlink transmission process of V-BLAST.

FIG. 2 is a diagram of the receiving process of the downlink of V-BLAST.

FIG. 3 is a flow chart of the V-BLAST array linear detection method using soft decision in the present invention.

Detailed ways

The downlink transmission process of V-BLAST is shown in FIG. 1 . The signal to be sent is encoded in step 110; in step 120, rate matching is performed on the encoded signal; in step 130, interleaving is performed on the rate matched signal; in step 140, carrier modulation is performed on the interleaved signal, modulation Mode can be determined according to specific needs, such as QPSK modulation, 8PSK modulation (8-phase Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation, i.e. quadrature amplitude modulation) modulation etc. can be adopted; in step 150, Split the modulated signal into M signals as required to form an M-dimensional column vector, where M represents the number of array elements of the transmitting antenna; in step 160, use the same spreading code and scrambling code for the M-dimensional column vector Perform frequency spreading and scrambling; then in step 170, the M-dimensional column vector after spreading and scrambling is transmitted through an antenna array composed of M antenna elements. Wherein, the mth (1<m<M) element of the M-dimensional column vector is transmitted through the mth antenna.

The receiving process of the downlink of V-BLAST is shown in FIG. 2 . In step 210, the receiving antenna array formed by N antenna elements receives the transmitted N-dimensional signal formed by multipath scattering; in step 220, the N-dimensional signal received by each antenna element is despread and descrambled respectively, Obtain a set of N-dimensional column vector signals; in step 230, apply the V-BLAST linear decorrelation detection method to detect the M-dimensional column vector signals emitted by the transmitting party; in step 240, regenerate the detected M-dimensional column vector signals Through the carrier demodulation mode corresponding to the transmitter's modulation method (as the transmitter adopts the QPSK mode to modulate the interleaved signal, the receiver adopts the corresponding QPSK carrier demodulation mode to demodulate the detected signal); in step 250 , perform deinterleaving on the demodulated signal; in step 260, decode the signal obtained by deinterleaving to obtain the data signal transmitted by the transmitter.

Among the above receiving methods, the V-BLAST linear decorrelation detection method is the core content of V-BLAST, which utilizes the zero-forcing decision feedback method in multi-user detection. That is, the strongest signal is detected first, and then the strongest signal is removed from the received signal as interference; then the strongest signal is detected in the received signal from which the strongest signal has been removed, and then removed as interference; All signals are detected. Then the obtained M strongest signals are the detected M-dimensional column vectors. The method is described in detail below with reference to FIG. 3 .

Assuming that the transmitter has M transmit antenna elements, and the receiver has N receive antenna elements, the channel transmission matrix from the transmitter to the receiver is H ^N*M , and h _ij is from the transmit array element j to the receive array element The transfer function of i, M≤N. Assuming that the carrier modulation of the sender adopts QPSK (Quadrature Phase Shift Keying) modulation, the M-dimensional column vector of the transmitting Symbol is $\stackrel{\&Right\; Arrow;}{a}={(a_1,a_2,\&Center\; Dot;\&Center\; Dot;\&Center\; Dot;,a_m)}^T,$ Receive Symbol N-dimensional column vector as ${\stackrel{\&Right\; Arrow;}{r}}_1=h\stackrel{\&Right\; Arrow;}{a}+\stackrel{\&Right\; Arrow;}{v}---\left(1\right)$

是宽平稳噪声。采用线性去相关检测，设顺序设置S＝{k₁，k₂，…，K_m}是接收Symbol N维列向量

中发射Symbol依次被检测出的顺序，权值向量 i＝1，2，…，M满足

是H的第k_j列。in,

is broad stationary noise. Using linear decorrelation detection, let the sequence setting S={k ₁ , k ₂ ,..., K _m } be the receiving Symbol N-dimensional column vector

The order in which Symbols are detected in turn, the weight vector i=1, 2,..., M satisfies

is the k _jth column of H.

The V-BLAST detection algorithm adopting the detection order of the present invention is as follows:

Initial settings:

i=1 (3.1)

G ₁ =H ⁺ (3.2)

k ₁ =argmin _j ‖(G ₁ ) _j ‖ ² (3.3)

Do the following iterative process: ${\stackrel{\&Right\; Arrow;}{w}}_{k_i}={\left(G_i\right)}_{k_i}^T---\left(3.4\right)$ ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i---\left(3.5\right)$ $G_{i+1}=h_{k_i}^{\&PlusMinus;}---\left(3.8\right)$ $k_{i+1}={\arg \min }_{j\&NotElement;\{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A0113564200131.png"\; state="\{\{state\}\}">k</figure-callout>}}_1,k_2,\&Center\; Dot;\&Center\; Dot;\&Center\; Dot;k_i\}}\left|\right|{\left(G_{i+1}\right)}_j|{|}^2---\left(3.9\right)$ $\mathrm{if}(i<m),i++---\left(3.10\right)$

进行量化操作。(3.7)表示从接收信号中去除检测出的最强的信号。(3.8)中， 表示将中已经检测出的Symbol对应的列向量去除后得到的矩阵。(3.9)意义与(3.3)类似，表示在G_i+1的行向量中找出范数最小的一个向量，并将这个向量的行序数(1，2，3…M)赋值给K_i+1。(3.10)表示(3.4)到(3.10)的迭代一直进行，直到将所有M个Symbol检测出来为止。The meanings of the above formulas are explained as follows: In (3.2), H ⁺ represents the pseudo-inverse of the channel transmission matrix H from the transmitter to the receiver. In (3.3), (G ₁ ) _j denotes the jth row vector of G ₁ . Equation (3.3) means finding a vector with the smallest norm among the row vectors of G ₁ , and assigning the row number (1, 2, 3...M) of this vector to k ₁ . (3.4) means to use the found ki _-th vector as the weight. (3.5) indicates that the weight is multiplied by the received Symbol column vector to obtain the k _ith Symbol (3.6) means the k _ith Symbol to be obtained

Do quantization. (3.7) means removing the strongest detected signal from the received signal. In (3.8), express will The matrix obtained after removing the column vector corresponding to the Symbol that has been detected in . The meaning of (3.9) is similar to that of (3.3), which means to find a vector with the smallest norm in the row vector of G _i+1 , and assign the row number (1, 2, 3...M) of this vector to K _{i+ 1} . (3.10) means that the iterations from (3.4) to (3.10) are carried out until all M Symbols are detected.

In (3.5), ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i$ $={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T({\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)---\left(3.11\right)$ $=a_{k_i}+{\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T(\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)$ $\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v$ Is the interference and noise items, subject to Gaussian distribution, set the variance as Then the signal-to-noise ratio of the _kith Symbol is $\mathrm{SNR}=\frac{{\left|a_{k_i}\right|}^2}{{\mathrm{\&sigma;}}_{k_i}^2{\left|\right|{\stackrel{\&Right\; Arrow;}{w}}_{k_i}\left|\right|}^2}---\left(3.12\right)$

中最强的Symbol。It can be seen from (3.12) that (3.3) finds a vector with the smallest norm in the row vector of G ₁ as the weight value, which means that (3.5) will detect

The strongest Symbol in .

(3.6) represents the process of quantization using the soft decision method. For a signal that has not been channel coded, the quantization process is a hard decision process. On the constellation diagram of the corresponding modulation method, the point with the closest Euclidean distance to the detected signal is taken as the quantized value of the signal. For channel-coded data, if the hard-decision quantization method is used, the quantization error will be large, which will affect the subsequent decoding accuracy, so the soft-decision method is used for quantization. Aiming at the V-BLAST array detection receiver adopting linear decorrelation detection, the present invention proposes a soft decision algorithm for quantization, that is, adopts hyperbolic tangent nonlinear detection method for quantization. For example, if QPSK modulation is used for transmitter carrier modulation, the soft decision algorithm can be expressed as:

Among them, tanh() represents the hyperbolic tangent function, real() represents the real part of a complex number, and imag() represents the imaginary part of a complex number

This soft decision algorithm is optimal in the sense of minimum mean square error, and its advantage is that when the signal-to-noise ratio is relatively large, $\tanh \left(\frac{\sqrt{2}\mathrm{real}\left({\mathrm{the\; y}}_{k_i}\right)}{{\mathrm{\&sigma;}}_{k_i}^2}\right)$ and $\tanh \left(\frac{\sqrt{2}\mathrm{imag}\left({\mathrm{the\; y}}_{k_i}\right)}{{\mathrm{\&sigma;}}_{k_i}^2}\right)$ close to ±1, tends to be accurate; when the signal-to-noise ratio is relatively small, the signal is submerged in the interference and noise. If the hard judgment method is used, the interference and noise play a decisive role in the judgment, and the probability of judgment error is very high. $\tanh \left(\frac{\sqrt{2}\mathrm{real}\left({\mathrm{the\; y}}_{k_i}\right)}{{\mathrm{\&sigma;}}_{k_i}^2}\right)$ and $\tanh \left(\frac{\sqrt{2}\mathrm{imag}\left({\mathrm{the\; y}}_{k_i}\right)}{{\mathrm{\&sigma;}}_{k_i}^2}\right)$ The transformation can reduce the probability of error. Using the soft decision algorithm, the signal transmitted by the transmitter can be detected more accurately at the receiver, thereby improving the accuracy of subsequent demodulation and decoding. The flow chart of the V-BLAST array detection and receiving method using soft decision algorithm and linear decorrelation detection is shown in FIG. 3 .

))，求出接收信号 中第i个最强的信号 在步骤S50，从接收的列向量信号中去除步骤d)中所求出的最强的信号

( )，得到将 中已经检测出的Symbol对应的列向量去除后的矩阵

求出 的伪逆，( $G_{i+1}=H_{k_i}^{\&PlusMinus;}$ )；在G_i+1的行向量中找出范数最小的一个向量( $k_{i+1}=\arg \mathrm{mi}{n}_{j\&NotElement;\{k_{1,}{k}_{2,}\&CenterDot;\&CenterDot;\&CenterDot;k_i\}}\left|\right|{\left(G_{i+1}\right)}_j|{|}^2$ )。在步骤S60，判断i是否大于M，如果i＜M，则设置i＝i+1，重复步骤S20到步骤S60；如果i＝M，则所求出的M个最强的信号( ...、

)即为所检测出的列向量。Receiver receives Symbol N-dimensional column vector $\stackrel{\&Right\; Arrow;}{r}={({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="A0113564200131.png"\; state="\{\{state\}\}">r</figure-callout>}}_1,r_2,\&CenterDot;\&CenterDot;\&CenterDot;,r_N)}^T,$ After descrambling and despreading are performed on each column vector, the V-BLAST linear detection process of the N-dimensional column vector signal is started. First, set the initialization condition in step S10: i=1, G ₁ =H ⁺ , k ₁ =argmin _j ∥(G ₁ ) _j ∥ ² where (G ₁ ) _j represents the jth row vector of G ₁ , k ₁ =argmin _j ‖(G ₁ ) _j ‖ ² means finding a vector with the smallest norm among the row vectors of G ₁ and assigning the row number (1, 2, 3...M) of this vector to k ₁ . In step S20, the k _i th vector found is used as the weight ( ${\stackrel{\&Right\; Arrow;}{w}}_{k_i}={\left(G_i\right)}_{k_i}^T$ ), determine the weight of linear decorrelation detection In step S30, the weight is multiplied by the received Symbol column vector to obtain the k _i th Symbol in the received signal ( ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i$ ). In step S40, quantize the obtained k _i th Symbol using a soft decision method (

)), find the received signal The ith strongest signal in In step S50, the strongest signal obtained in step d) is removed from the received column vector signal

( ), get the The matrix after removing the column vector corresponding to the Symbol that has been detected in

find out Pseudo-inverse of , ( $G_{i+1}=h_{k_i}^{\&PlusMinus;}$ ); Find a vector with the smallest norm in the row vector of G _i+1 ( $k_{i+1}=\arg \mathrm{mi}{\mathrm{no}}_{j\&NotElement;\{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A0113564200131.png"\; state="\{\{state\}\}">k</figure-callout>}}_{1,}{k}_{2,}\&Center\; Dot;\&Center\; Dot;\&Center\; Dot;k_i\}}\left|\right|{\left(G_{i+1}\right)}_j|{|}^2$ ). In step S60, judge whether i is greater than M, if i＜M, then set i=i+1, repeat step S20 to step S60; If i=M, then the M strongest signals ( ...,

) is the detected column vector.

The protection scope of the present invention is set forth in the appended claims. However, any obvious modifications within the gist of the present invention should also fall within the protection scope of the present invention.

Claims (5)

1. A V-BLAST array linear decorrelation detection method, wherein the transmitter transmits a Symbol (symbol) M-dimensional column vector $\stackrel{\&Right\; Arrow;}{a}={(a_1,a_2,\&CenterDot;\&CenterDot;\&Center\; Dot;,a_m)}^T,$ The channel transfer matrix from the transmitter to the receiver is H ^N*M , h _ij in H ^N*M is the transfer function from the transmitting array element j to the receiving array element i, M≤N, characterized in that the method includes: a) Receive Symbol N-dimensional column vector $\stackrel{\&Right\; Arrow;}{r}={(r_1,r_2,\&Center\; Dot;\&CenterDot;\&CenterDot;,r_N)}^T;$ b) Set initialization conditions in the memory: i=1, G ₁ =H ⁺ , k ₁ = argmin _j ‖(G ₁ ) _j ‖ ² where (G ₁ ) _j represents the jth row vector of G ₁ , k ₁ ＝argmin _j ‖(G ₁ ) _j ‖ ² means to find the one with the smallest norm among the row vectors of G ₁ vector, and assign the row number of this vector to k ₁ ; c) Use the k _i th vector found as the weight, ${\stackrel{\&Right\; Arrow;}{w}}_{k_i}={\left(G_i\right)}_{k_i}^T,$ Determining Weights for Linear Decorrelation Detection

And multiply the weight with the received Symbol column vector to get the k _ith Symbol, ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_{i;}$ d) Quantize the k _i th Symbol column vector obtained using a soft decision method get the received signal

The ith strongest signal in

yes

estimated value of e) Remove the strongest signal obtained in step d) from the received column vector signal get will The matrix after removing the column vector corresponding to the Symbol that has been detected in

f) find out

the pseudo-inverse of $G_{i+i}=h_{k_i}^{\&PlusMinus;};$ g) Find a vector with the smallest norm in the row vector of G _i+1 $k_{i+1}=\arg \mathrm{mi}{\mathrm{no}}_{j\&NotElement;\{k_1,k_2,\&Center\; Dot;\&CenterDot;\&Center\; Dot;k_i\}}\left|\right|{\left(G_{i+1}\right)}_j|{|}^2$ h) If i<M, then i=i+1, return to step c); i) If i=M, the M strongest signals obtained

...

is the detected column vector. 2. The V-BLAST array linear detection method as claimed in claim 1, characterized in that: 5. said soft decision method is a hyperbolic tangent quantization method. 3. V-BLAST array linear detection method as claimed in claim 1, is characterized in that: the launch Symbol M dimension column vector of the launch party $\stackrel{\&Right\; Arrow;}{a}={(a_1,a_2,\&CenterDot;\&CenterDot;\&Center\; Dot;,a_m)}^T$ It is a signal modulated by QPSK method. 4. The V-BLAST array linear detection method as claimed in claim 3, characterized in that: said soft decision method is a hyperbolic tangent quantization method. 5. V-BLAST array linear detection method as claimed in claim 4, is characterized in that described hyperbolic tangent quantization method is: in, ${\mathrm{the\; y}}_{k_i}={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T{\stackrel{\&Right\; Arrow;}{r}}_i$ $={\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T({\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)$ $=a_{k_i}+{\stackrel{\&Right\; Arrow;}{w}}_{k_i}^T(\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v)$ $\underset{l=i+1}{\overset{m}{\mathrm{\&Sigma;}}}{\stackrel{\&Right\; Arrow;}{h}}_{k_i}{a}_{k_i}+v$ Is the interference and noise items, subject to Gaussian distribution, the variance is

v is wide stationary noise; real() means to take the real part of the complex number, and imag() means to take the imaginary part of the complex number.

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