CN101944933B - Method for suppressing residual multi-user interference in 2-dimensional block spread spectrum system based on 2-dimensional minimum mean square error detection algorithm - Google Patents

Abstract

A method for suppressing residual multi-user interference in a 2-dimensional block spread system based on 2-dimensional minimum mean square error (2D MMSE) detection algorithm belongs to the field of communications and aims to solve the problem of residual multi-user interference in the 2-dimensional block spread system in a fast fading channel. The invention aims at the fast fading channel, compared with the traditional slow fading channel, the 2D MMSE detection link is added during receiving the signal. After being transformed to the frequency domain through fast Fourier transform (FFT), the signal received by a receiver is subjected to 2D MMSE detection. The weight of the signal in the frequency domain is changed and is more reasonable. Multi-user detection and frequency domain equalization can be completed through 2D MMSE detection to resist the impact of multipath fading channels. The detection algorithm has low implementation complexity and good bit error rate performance and can well improve the residual multi-user interference generated because the channel gain can not maintain constant in the continuous blocks.

Description

Based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm

Technical field

The present invention relates to belong to the communications field based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm.

Background technology

Up link (Uplink for mobile radio system; UL) system; a plurality of users often can access same base station (Base station simultaneously; BS); but because each user position is different; the time that each user arrives the base station is not quite similar; distinguish the user although in cdma system, can adopt different orthogonal intersections; but because the asynchronous and channel delay spread of up link; the user can not keep orthogonality to each other, therefore can produce serious multiple access and disturb (MAI).MAI will seriously reduce the transmission performance of up link.How to adopt suitable technology to avoid MAI, be one of emphasis of scholar's research always.

The New Two Dimensional piece spread spectrum (2D that proposes at present, 2-dimenstional Block spread CDMA) technology, referring to Fig. 1 and Fig. 2, wherein Figure 1 shows that the sending and receiving schematic diagram of single carrier CDMA (SC-CDMA) system, Fig. 2 is the sending and receiving schematic diagram of CDMA multiple carrier (MC-CDMA) system, under steady slow fading channel (slow flatfading channel), compare with traditional multiuser detection algorithm, it has low complex degree, higher transmission performance can well solve the MAI problem, is a kind of novel up link connecting system structure.

Yet in the introduction to two-dimensional block spread spectrum system, can find out why two-dimensional block spread spectrum system can avoid multi-user interference, the one, owing to adopt orthogonal code to make the user keep quadrature, the 2nd, suppose that channel is the slow fading system, remains unchanged in the time interval at continuous piece (piece).And when channel becomes the rapid fading system, channel parameter will change in the time at continuous piece, to destroy the entire system performance this moment, especially as two-dimensional block spread spectrum system associating MIMO (Multiple-InputMultiple-Out-put, multiple-input and multiple-output) during diversity technique, performance will sharply descend.

Summary of the invention

The present invention seeks to the problem for the residual multi-user interference of the two-dimensional block spread spectrum system that solves fast fading channel, provide based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm.

The present invention is based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively the piece spread spectrum, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 3, the U road piece spread spectrum that step 2 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 4, employing reception antenna connect the U road signal of step 3 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 5, the processing that step 4 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 6, the piece despreading that step 5 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 7, the frequency-region signal that step 6 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Step 8, the U road detection signal that step 7 is obtained carry out respectively invert fast fourier transformation, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out respectively the chip-level despreading after step 9, the U road conversion that step 8 is obtained, obtains signal after the U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

Under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum and interweave, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively invert fast fourier transformation, obtains time-domain signal after the U road conversion;

Time-domain signal carries out respectively the piece spread spectrum after step 3, the U road conversion that step 2 is obtained, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 4, the U road piece spread spectrum that step 3 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the signal of step 4 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 6, the processing that step 5 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 7, the piece despreading that step 6 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Time-domain signal carries out respectively chip-level despreading and deinterleaving after step 9, the U road conversion that step 8 is obtained, obtains signal after the U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

Advantage of the present invention: detect (2D-MMSE) scheme based on two-dimentional least mean-square error, system compares with conventional two-dimensional piece despreading, and the 2D-MMSE algorithm is better than traditional detection algorithm, and traditional detection algorithm is poor-performing then.This is because traditional detection algorithm is not considered the impact of noise, so poor-performing; The 2D-MMSE algorithm considers that noise effect so performance are better than traditional detection algorithm.This detection algorithm can improve the remaining multi-user interference that can not keep constant to produce owing to channel gain in continuous blocks, and complexity is relatively moderate.

Description of drawings

Fig. 1 be in the background technology under the SC-CDMA system two-dimensional block spread spectrum system transmit and receive structural representation;

Fig. 2 be in the background technology under the MC-CDMA system two-dimensional block spread spectrum system transmit and receive structural representation;

Fig. 3 be the method for the invention under the SC-CDMA system two-dimensional block spread spectrum system transmit and receive structural representation;

Fig. 4 be the method for the invention under the MC-CDMA system two-dimensional block spread spectrum system transmit and receive structural representation;

Fig. 5 is multi-user interference forming process schematic diagram;

Fig. 6 is the BER Simulation schematic diagram, among the figure-and ■-ber curve of system when representing piece despreading algorithm, The ber curve of system when representing maximum likelihood algorithm.

Embodiment

Embodiment one: below in conjunction with Fig. 3 present embodiment is described, present embodiment is based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively the piece spread spectrum, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 3, the U road piece spread spectrum that step 2 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 4, employing reception antenna connect the U road signal of step 3 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 5, the processing that step 4 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 6, the piece despreading that step 5 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 7, the frequency-region signal that step 6 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Step 8, the U road detection signal that step 7 is obtained carry out respectively invert fast fourier transformation, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out respectively the chip-level despreading after step 9, the U road conversion that step 8 is obtained, obtains signal after the U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

Embodiment two: below in conjunction with Fig. 4 to Fig. 6 present embodiment is described, present embodiment is based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum and interweave, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively invert fast fourier transformation, obtains time-domain signal after the U road conversion;

Time-domain signal carries out respectively the piece spread spectrum after step 3, the U road conversion that step 2 is obtained, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 4, the U road piece spread spectrum that step 3 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the signal of step 4 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 6, the processing that step 5 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 7, the piece despreading that step 6 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Time-domain signal carries out respectively chip-level despreading and deinterleaving after step 9, the U road conversion that step 8 is obtained, obtains signal after the U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

Operation principle:

The square root Nyquist chip formed filter that the employing that transmits and receives is identical; And receive and use the ideal time.Therefore the transmission course of this paper adopts the discrete-time series of chip-spaced to represent.

Representative is less than or equal to the maximum integer of real variable a; Representative is more than or equal to the smallest positive integral of real variable a

Total U user, namely U road signal will be processed, and in order to express easily, analyzes as an example of u road signal example, and the information series behind u road user's the Data Modulation is { d _u(n); N=0～N _c/ SF _f-1}, here SF _fRepresent the spreading factor length of chip-level, here SF _tRepresent the spreading factor length of piece level, N _cBe the length scale of FFT (or IFFT) conversion, FFT is fast fourier transform, and IFFT is invert fast fourier transformation.For the chip-level spread spectrum, adopt frequency expansion sequence to be

And frequency expansion sequence

Satisfy

Sequence behind the spread spectrum will with scrambler sequence

Multiply each other, make it become transmitting of similar white Gaussian noise.For the SC-CDMA system, its transmitting sequence Expression formula is shown in formula (1):

For the MC-CDMA system, the sequence behind the chip-level spread spectrum

Need through N _cPoint IFFT conversion is to obtain the MC-CDMA signal

Shown in formula (2).Here it should be noted that in order to take full advantage of the frequency selective characteristic of channel, SF _f* (N _c/ SF _f) will at first act on the sequence behind the chip-level spread spectrum, make calling sequence at N _cThe first-class distance of the individual subcarrier (N of being separated by _c/ SF _f) spread out, and then by the IFFT conversion.

$s_u^{\mathrm{MC}}\left(t\right)=\frac{1}{\sqrt{N_c}}\underset{n=0}{\overset{N_c/S{F}_f-1}{\mathrm{\&Sigma;}}}\underset{i=0}{\overset{S{F}_f-1}{\mathrm{\&Sigma;}}}\left[\begin{array}{c}{s}_u^{\mathrm{SC}}(n\&CenterDot;S{F}_f+i)\\ \&times;\exp \{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027540240000051.png,HDA0000027540240000052.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{t}{N_c}\&CenterDot;(n+i\frac{N_c}{S{F}_f})\}\end{array}\right]---\left(2\right)$

Transmit SC-CDMA and MC-CDMA unified with { s (t); T=0～N _c-1} represents, shown in formula (3):

$s_u\left(t\right)=\left\{\begin{array}{ccc}{s}_u^{\mathrm{SC}}\left(t\right)& \mathrm{for}& \mathrm{SC}-\mathrm{CDMA}\\ s_u^{\mathrm{MC}}\left(t\right)& \mathrm{for}& \mathrm{MC}-\mathrm{CDMA}\end{array}\right.----\left(3\right)$

Although the SC-CDMA transmitting terminal does not have the IFFT conversion, we will every N _cIndividual bit number is processed as one group of transmit data blocks.Then N _gIndividual Cyclic Prefix will insert the effect that each interblock is finished the protection interval.

Therefore, for u (individual user's the m (m=0～SF of u=0～U-1) _t-1) transfer sequence of individual piece can be expressed as:

${\hat{s}}_{m,u}\left(t\right)=\sqrt{\frac{2E_c}{T_c}}{s}_u\left(t\right)c_u^{S{F}_t}\left(m\right)---\left(4\right)$

T=0～N _c-1; Wherein

Be the orthogonal intersection sequence; E _cAnd T _cRepresent respectively the duration of energy He each chip of each chip.

M its channel of piece h for u user _uImpulse response (τ) is expressed as:

$h_{m,u}\left(\mathrm{\&tau;}\right)=\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,u,l}\mathrm{\&delta;}(\mathrm{\&tau;}-{\mathrm{\&tau;}}_{u,l})---\left(5\right)$

Here h _{M, u, l}And τ _{M, u, l}Represent respectively u user in the time delay factor of multiple path gain factor and Qi Di 1 paths of m piece, and channel gain h _{M, u, l}At time interval T=T _c(N _c+ N _g) in be constant.Suppose τ _{U, l}T _cThe time interval postpones, and its expression formula is τ _{U, l}=τ _u+ lT _c, l=0～L-1, τ _uIt is u user's initial transmission time migration.Here suppose GI interval greater than { τ _{U, l}Maximum time postpone, to avoid intersymbol interference.Admittedly after removing GI, receiving signal can be expressed as:

$r_m\left(t\right)=\underset{u=0}{\overset{U-1}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,u,l}{\hat{s}}_{m,u}(t-{\mathrm{\&iota;}}_{u,l})+n_m\left(t\right)---\left(6\right)$

N wherein _m(t) be the white complex gaussian noise signal of zero-mean, its variance is for being 2N ₀/ T _c(N ₀The one-sided power spectrum density of white Gaussian noise).

Said process is the emission process of signal, begins to analyze receiving course below us, before explanation receive mode of the present invention, introduces first the despreading of the conventional block utmost point and detects the process that receives signal, referring to illustrated in figures 1 and 2.

The despreading of piece level can be expressed as:

$r_u\left(t\right)=\frac{1}{S{F}_t}\underset{m=0}{\overset{S{F}_t-1}{\mathrm{\&Sigma;}}}{r}_m\left(t\right){\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}$

$=\frac{1}{S{F}_t}\underset{m=0}{\overset{S{F}_t-1}{\mathrm{\&Sigma;}}}\{\sqrt{\frac{2E_c}{T_c}}\underset{u=0}{\overset{U-1}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,u,l}{s}_u(t-{\mathrm{\&tau;}}_{u,l})c_u^{S{F}_t}\left(m\right)+n_m\left(t\right)\}{\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}$

(7)

$=\sqrt{\frac{2E_c}{T_c}}\&CenterDot;\underset{u^{\&prime;}=0}{\overset{U-1}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,n,l}{s}_u(t-{\mathrm{\&tau;}}_{u,l})\left\{\frac{1}{S{F}_t}\underset{m=0}{\overset{S{F}_t-1}{\mathrm{\&Sigma;}}}\right\{c_{u^{\&prime;}}^{S{F}_t}\left(m\right)\left\}{\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}\right\}$

$+\frac{1}{S{F}_t}\underset{m=0}{\overset{{\mathrm{SF}}_t-1}{\mathrm{\&Sigma;}}}{n}_m\left(t\right){\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}$

When channel was slow fading, meaned at SF this moment _tChannel gain remains unchanged in the individual continuous blocks, i.e. h _u(τ) ≈ h _{M, u}(τ), (m=0～SF _t-1); Because

Keep quadrature, this moment, MAI can be shifted out fully, and formula (7) can be expressed as:

$r_u\left(t\right)=\sqrt{\frac{2E_c}{T_c}}\&CenterDot;\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{u,l}{s}_u(t-{\mathrm{\&tau;}}_{u,l})+\frac{1}{S{F}_t}\underset{m=0}{\overset{S{F}_t-1}{\mathrm{\&Sigma;}}}{n}_m\left(t\right){\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}---\left(8\right)$

Therefore multiple user signals can represent to be represented with the single-user receiver signal.Reception signal { r with u user _u(k) }, channel gain { h _u(τ) } and noise component(s) be transformed into frequency-region signal (k=0～N by Nc point FFT _c-1) be expressed as:

$\left\{\begin{array}{c}{R}_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{N_c-1}{\mathrm{\&Sigma;}}}{r}_u\left(t\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027540240000051.png,HDA0000027540240000052.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{t}{N_c})\\ H_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{u,l}\left(t\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027540240000051.png,HDA0000027540240000052.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{{\mathrm{\&tau;}}_{u,l}}{N_c})\\ {\mathrm{\&Pi;}}_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{N_c-1}{\mathrm{\&Sigma;}}}\left\{\frac{1}{S{F}_t}\underset{m=0}{\overset{S{F}_{t-1}}{\mathrm{\&Sigma;}}}{n}_m\left(t\right){\left\{c_u^{S{F}_t}\left(m\right)\right\}}^{*}\right\}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027540240000051.png,HDA0000027540240000052.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{t}{N_c})\end{array}\right..---\left(9\right)$

So { R _u(k) } can be expressed as:

$R_u\left(k\right)=\sqrt{\frac{2E_c}{T_c}}{H}_u\left(k\right)S_u\left(k\right)+{\mathrm{\&Pi;}}_u\left(k\right)---\left(10\right)$

The frequency domain equalization expression formula is:

Here w _u(k) be MMSE (least mean-square error) weight factor, be defined as:

$w_u\left(k\right)=\frac{H_u^{*}\left(k\right)}{{\left|H_u\left(k\right)\right|}^2+{(S{F}_t\&CenterDot;\frac{E_c}{N_0})}^{-1}}---\left(12\right)$

Convert frequency-region signal to time-domain signal by IFFT for the SC-CDMA signal, then despreading and judgement are carried out in the chip of chip-level, obtain transmitted signal; Then directly carry out despreading and the judgement of chip-level for the MC-CDMA signal, obtain transmitted signal.

More than to the despreading of the conventional block utmost point with detect the process narration that receives signal, be based on the hypothesis of slow fading channel, namely channel gain remains unchanged in SFt continuous blocks, MAI can perfectly soundly eliminate at this moment.Yet many times, channel is not slow fading channel, and this moment, residual MAI will reduce the error rate (BER) performance of system.Therefore present embodiment provides solution for this problem.Here discuss as an example with SC-CDMA, comprise the reception signal schematic representation among Fig. 3, Fig. 5 is that interfering process forms analysis chart.

The below introduces two-dimentional least mean-square error and detects (two-dimentional MMSE) this part algorithm.

Because the weight coefficient of the FDE of single user system is a vector, claim that the weight of this moment is one dimension (1-dimensional, 1D) weight; And for multi-user system, this moment, the weight of FDE was the complex matrix form, and is corresponding with the 1D system, is called two dimension (2-dimensional, 2D) weight.

So frequency-region signal of u user Can be expressed as:

Wherein

1-by-SFt weight vector matrix, SF _t-by-1 receives the signal phasor matrix.Weight matrix can produce by the Moore-Penrose mode.Definition e (k) is:

$e\left(k\right)=\sqrt{\frac{2E_c}{T_c}}{S}_u\left(k\right)-w_u\left(k\right)R\left(k\right)---\left(14\right)$

So weight w _u(k) can be expressed as

$w_u\left(k\right)=H_u^H\left(k\right){[H\left(k\right)H^H\left(k\right)+{\left(\frac{C\&CenterDot;E_c}{N_0}\right)}^{-1}{I}_{S{F}_t}]}^{-1}---\left(15\right)$

Here H (k)=[H ₀(k) ... H _U-1(k)] be SF _t-by-U complex channel gain matrix, wherein the element of the capable u row of m is H _{M, u}(k); And

SF _t-by-SF _tUnit matrix.

Convert frequency-region signal to time-domain signal by IFFT for the SC-CDMA signal, then despreading and judgement are carried out in the chip of chip-level, obtain transmitted signal; Then directly carry out despreading and the judgement of chip-level for the MC-CDMA signal, obtain transmitted signal.

Because 2D-MMSE frequency domain equalization weight has been considered the impact of white Gaussian noise, so 2D-MMSE has better bit error rate performance than traditional detection algorithm, and BER Simulation as shown in Figure 6.

The present invention be directed to fast fading channel, compare with traditional slow fading channel, when receiving signal, added two-dimentional MMSE detection.After signal that receiver receives changes to frequency domain by FFT, by two-dimentional MMSE detection, finish simultaneously Multiuser Detection and frequency domain equalization with the purpose of opposing multidiameter fading channel impact, implementation complexity is low, have good bit error rate performance, can fine improvement because the remaining multi-user interference that channel gain can not keep constant to produce in continuous blocks.

Claims (2)

1. based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm, it is characterized in that, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively the piece spread spectrum, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 3, the U road piece spread spectrum that step 2 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 4, employing reception antenna connect the U road signal of step 3 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 5, the processing that step 4 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 6, the piece despreading that step 5 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 7, the frequency-region signal that step 6 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Carry out respectively invert fast fourier transformation behind step 8, the U road detection signal with the step 7 acquisition, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out respectively the chip-level despreading after step 9, the U road conversion that step 8 is obtained, obtains signal after the U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

2. based on the method for suppressing residual multi-user interference in the two-dimensional block spread spectrum system of two-dimentional least mean-square error detection algorithm, it is characterized in that, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out respectively the chip-level spread spectrum and interweave, obtain the signal behind the chip-level spread spectrum of U road;

Signal behind step 2, the U road chip-level spread spectrum that step 1 is obtained carries out respectively invert fast fourier transformation, obtains time-domain signal after the U road conversion;

Time-domain signal carries out respectively the piece spread spectrum after step 3, the U road conversion that step 2 is obtained, obtains the signal behind the piece spread spectrum of U road;

Signal behind step 4, the U road piece spread spectrum that step 3 is obtained adds respectively the protection interval to be processed, the U road signal after obtaining to process, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the signal of step 4 emission, and go to protect the interval to process the signal that receives, the signal after obtaining to process;

Signal after step 6, the processing that step 5 is obtained carries out the piece despreading to be processed, and obtains the signal after the piece despreading;

Signal after step 7, the piece despreading that step 6 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out frequency domain equalization and the detection of two-dimentional least mean-square error, change the weight of described frequency-region signal, obtain the U road and detect rear signal;

Step 9, the rear signal of U road detection that step 8 is obtained carry out respectively chip-level despreading and deinterleaving, signal after the acquisition U road despreading;

Export after the signal demodulation after step 10, the U road despreading that step 9 is obtained;

U is positive integer.

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