CN101951278A - Method for inhibiting residual multi-user interference in two-dimensional block spread spectrum system based on parallel interference cancellation and iterative detection - Google Patents

Abstract

The invention relates to a method for inhibiting residual multi-user interference in a two-dimensional block spread spectrum system based on parallel interference cancellation and iterative detection, which belongs to the field of communication and solves the problem of the residual multi-user interference in the two-dimensional block spread spectrum system of a quick fading channel. In the two-dimensional block spread spectrum system of the invention, the scheme of parallel interference cancellation with iterative detection is adopted for eliminating multi-user interference. Two schemes are arranged for setting an iterative initial value: in the first scheme, the iterative initial value is obtained by one-dimensional MMSE (Minimum Mean Square Error) frequency domain equalization; and in the second scheme, two-dimensional MMSE is adopted for changing the weight of frequency domain equalization; repeated iteration is carried out; data are not outputted until multi-user interference is small enough; after each path of signals are iterated, self multi-user interference signals of the modulated and outputted data are extracted; the scheme of parallel interference cancellation is obtained by subtracting multi-user interference signals of all other paths from the iterated value of each path of frequency domain equalization; and the residual multi-user interference is effectively eliminated through repeated iteration and parallel interference cancellation.

Description

Based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection

Technical field

The present invention relates to belong to the communications field based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection.

Background technology

Up link (Uplink for mobile radio system; UL) system; a plurality of users often can insert same base station (Base station simultaneously; BS); but because each user position difference; 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, and therefore can produce serious multi-user inserts interference (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 present novel two-dimensional block spread spectrum (2D that proposes, 2-dimenstional Block spread CDMA) technology, referring to Fig. 1 and Fig. 2, wherein Figure 1 shows that the transmission of single carrier CDMA (SC-CDMA) system and receive schematic diagram, Fig. 2 is the transmission of CDMA multiple carrier (MC-CDMA) system and receives schematic diagram, under steady slow fading channel (slow flatfading channel), compare with traditional multiuser detection algorithm, it has low complex degree, can well solve the MAI problem with higher transmission performance, be a kind of novel up link connecting system structure.

Yet in introduction to the two-dimensional block spread spectrum system, why the two-dimensional block spread spectrum system can avoid multi-user interference as can be seen, 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 problem, provide based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection for the residual multi-user interference of the two-dimensional block spread spectrum system that solves fast fading channel.

The present invention is based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, four kinds of schemes are provided.

First kind of scheme: iterative initial value detects the weight that changes frequency domain equalization by two-dimentional least mean-square error and obtains, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 5, the processing that step 4 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 6, the frequency-region signal that step 5 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 the back signal as iterative initial value;

Step 7, the U road iterative initial value that step 6 is obtained carry out invert fast fourier transformation respectively, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out the chip-level despreading respectively after step 8, the U road conversion that step 7 is obtained, obtains signal after the U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

Second kind of scheme: iterative initial value detects the weight that changes frequency domain equalization by two-dimentional least mean-square error and obtains, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 6, the processing 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 the back signal as iterative initial value;

Step 8, the U road iterative initial value that step 7 is obtained carry out chip-level despreading and deinterleaving respectively, signal after the acquisition U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

The third scheme: iterative initial value is separated back acquisition frequently by piece, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

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

Step 7, the frequency-region signal that step 6 is obtained carry out based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

The 4th kind of scheme: iterative initial value is separated back acquisition frequently by piece, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

U road signal after step 7, the processing that step 6 is obtained carries out fast fourier transform, obtains the U road signal of frequency domain after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out changing the weight of described frequency-region signal based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

Advantage of the present invention: based on the detection scheme of iteration, separate enlarging system with conventional two-dimensional piece spread spectrum and compare, have the good error rate (BER) performance, can obviously improve because the remaining multi-user interference that channel gain can not keep constant to produce in continuous blocks.

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 multi-user interference forming process schematic diagram;

Fig. 4 is execution mode one a described system configuration schematic diagram;

Fig. 5 is execution mode two described system configuration schematic diagrames;

Fig. 6 is execution mode three described system configuration schematic diagrames;

Fig. 7 is execution mode four described system configuration schematic diagrames;

Fig. 8 is an error rate emulation schematic diagram, among the figure The ber curve of system when representing conventional block despreading algorithm;

Represent the ber curve of system when adopting Iterative detection algorithm, iterative initial value detects the weight that changes frequency domain equalization by two-dimentional least mean-square error and obtains, at this moment iterations i=4;

Represent the ber curve of system when adopting Iterative detection algorithm, iterative initial value is separated back acquisition frequently, iterations i=4 at this moment by piece.

Embodiment

Embodiment one: below in conjunction with Fig. 4 present embodiment is described, present embodiment is based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 5, the processing that step 4 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 6, the frequency-region signal that step 5 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 the back signal as iterative initial value;

Step 7, the U road iterative initial value that step 6 is obtained carry out invert fast fourier transformation respectively, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out the chip-level despreading respectively after step 8, the U road conversion that step 7 is obtained, obtains signal after the U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then, and described error rate is meant this modulation dateout and modulated the difference of dateout last time and the ratio of modulating dateout last time, and common iteration 4 times and above iterative data remain on stable state substantially,

U is a positive integer.

Wherein, step 9 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is: step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out the piece spread spectrum, obtains the signal behind the piece spread spectrum;

Signal behind step 4, the piece spread spectrum that step 3 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

Embodiment two: below in conjunction with Fig. 5 present embodiment is described, present embodiment is based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 6, the processing 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 the back signal as iterative initial value;

Step 8, the U road iterative initial value that step 7 is obtained carry out chip-level despreading and deinterleaving respectively, signal after the acquisition U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then, and described error rate is meant this modulation dateout and modulated the difference of dateout last time and the ratio of modulating dateout last time, and common iteration 4 times and above iterative data remain on stable state substantially,

U is a positive integer.

Wherein, step 9 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum and interweaves after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out invert fast fourier transformation, obtains time-domain signal;

Step 4, the time-domain signal that step 3 is obtained carry out the piece spread spectrum, the signal behind the acquisition piece spread spectrum;

Signal behind step 5, the piece spread spectrum that step 4 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

Embodiment three: below in conjunction with Fig. 6 present embodiment is described, present embodiment is based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

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

Step 7, the frequency-region signal that step 6 is obtained carry out based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then, and described error rate is meant this modulation dateout and modulated the difference of dateout last time and the ratio of modulating dateout last time, and common iteration 4 times and above iterative data remain on stable state substantially,

U is a positive integer.

Wherein, step 10 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out the piece spread spectrum, obtains the signal behind the piece spread spectrum;

Signal behind step 4, the piece spread spectrum that step 3 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

Embodiment four: below in conjunction with Fig. 3, Fig. 7 and Fig. 8 present embodiment is described, present embodiment is based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

U road signal after step 7, the processing that step 6 is obtained carries out fast fourier transform, obtains the U road signal of frequency domain after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out changing the weight of described frequency-region signal based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then, and described error rate is meant this modulation dateout and modulated the difference of dateout last time and the ratio of modulating dateout last time, and common iteration 4 times and above iterative data remain on stable state substantially,

U is a positive integer.

Wherein, step 10 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum and interweaves after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out invert fast fourier transformation, obtains time-domain signal;

Step 4, the time-domain signal that step 3 is obtained carry out the piece spread spectrum, the signal behind the acquisition piece spread spectrum;

Signal behind step 5, the piece spread spectrum that step 4 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

Operation principle:

The square root Nyquist chip formed filter that the employing that transmits and receives is identical; And receive and use the desirable sampling 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, promptly U road signal will be handled, and in order to express easily, is that example is analyzed with u road signal, and the information series after the modulation of u road user's data is { d _u(n); N=0～N _c/ SF _f-1}, SF here _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 a fast fourier transform, and IFFT is an invert fast fourier transformation.For the chip-level spread spectrum, adopt frequency expansion sequence be

T=0～SF _f-1}, and frequency expansion sequence

Satisfy

Sequence behind the spread spectrum will with scrambler sequence T=0～N _c-1} multiplies each other, and makes it become transmitting of similar white Gaussian noise.For the SC-CDMA system, its transmitting sequence

T=0～N _c-1} expression formula is as shown in Equation (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

As shown in Equation (2).Here it should be noted that in order to make full use 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.

$s_u^{\mathrm{MC}}\left(t\right)=\frac{1}{\sqrt{N_c}}\underset{n=0}{\overset{N_c/{\mathrm{SF}}_f-1}{\mathrm{\&Sigma;}}}\underset{i=1}{\overset{{\mathrm{SF}}_f-1}{\mathrm{\&Sigma;}}}\left[\begin{array}{c}{s}_u^{\mathrm{SC}}(n\&CenterDot;{\mathrm{SF}}_f+i)\\ \&times;\exp \{\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027559000000031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{t}{N_c}\&CenterDot;(n+i\frac{N_c}{{\mathrm{SF}}_f})\}\end{array}\right]---\left(2\right)$

Transmit SC-CDMA and MC-CDMA unified with { s (t); T=0～N _c-1} represents, as formula (3) institute not:

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

Although the SC-CDMA transmitting terminal does not have the IFFT conversion, we will every N _cIndividual bit number is handled as one group of transmit data blocks.N then _gIndividual Cyclic Prefix will insert each interblock and finish protection effect at 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:

${\hat{s}}_{m,u}\left(t\right)=\sqrt{\frac{{2E}_c}{T_c}}{s}_u\left(t\right)c_u^{{\mathrm{SF}}_t}\left(m\right)---\left(4\right)$

T=0～N _c-1; Wherein

M=0～SF _t-1} is the orthogonal intersection sequence; E _cAnd T _cRepresent the duration of energy He each chip of each chip respectively.

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 the time delay factor of u user respectively at the 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}Be 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, received signal can be expressed as:

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

N wherein _m(t) be the white complex gaussian noise signal of zero-mean, its variance is for being 2N ₀/ T _c(N ₀Be the 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 the despreading of the conventional block utmost point earlier and detects the process of received signal, referring to Fig. 2 and shown in Figure 4.

The despreading of piece level can be expressed as:

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

$\begin{array}{c}=\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="SF"\; filenames="HDA0000027559000000031.png"\; state="\{\{state\}\}">SF</figure-callout>}}_1}\underset{m=0}{\overset{{\mathrm{SF}}_t-1}{\mathrm{\&Sigma;}}}\{\sqrt{\frac{{2E}_c}{T_c}}\underset{u=0}{\overset{U-1}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,u,l}{s}_u(t-{\mathrm{\&tau;}}_{u,l})c_u^{{\mathrm{SF}}_t}\left(m\right)+n_m\left(t\right)\}{\left\{c_u^{{\mathrm{SF}}_t}\left(m\right)\right\}}^{*}\\ =\sqrt{\frac{{2E}_c}{T_c}}\&CenterDot;\underset{u\&prime;=0}{\overset{U-1}{\mathrm{\&Sigma;}}}\underset{l=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{m,u,l}{s}_u(t-{\mathrm{\&tau;}}_{u,l})\left\{\frac{1}{{\mathrm{SF}}_t}\underset{m=0}{\overset{{\mathrm{SF}}_t-1}{\mathrm{\&Sigma;}}}\right\{c_{u\&prime;}^{{\mathrm{SF}}_t}\left(m\right)\left\}\right\{c_u^{{\mathrm{SF}}_t}\left(m\right){\}}^{*}\}\end{array}---\left(7\right)$

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

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

(u=0～U-1) keep quadrature, this moment, MAI can be shifted out fully, and formula (7) can be expressed as:

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

Therefore multiple user signals can be represented to be represented with single user's received signal.Received 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:

$\left\{\begin{array}{c}{R}_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{N_c-1}{\mathrm{\&Sigma;}}}{r}_u\left(t\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027559000000031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{t}{N_c})\\ H_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_{u,l}\left(t\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027559000000031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{{\mathrm{\&tau;}}_{u,l}}{N_c})\\ {\mathrm{\&Pi;}}_u\left(k\right)=\frac{1}{\sqrt{N_c}}\underset{t=0}{\overset{N_c-1}{\mathrm{\&Sigma;}}}\left\{\frac{1}{{\mathrm{SF}}_t}\underset{m=0}{\overset{{\mathrm{SF}}_t-1}{\mathrm{\&Sigma;}}}{n}_m\left(t\right)\right\{c_u^{{\mathrm{SF}}_t}\left(m\right){\}}^{*}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="HDA0000027559000000031.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;k}\frac{t}{N_c})\end{array}\right..---\left(9\right)$

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 one dimension MMSE (one dimension least mean-square error) weight factor, be defined as:

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

The second time and later iterative detection adopt formula (12) to change the weight of frequency domain equalization, carry out repeatedly iteration.

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

Because the weight coefficient of the frequency domain equalization 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 frequency domain equalization was the complex matrix form, and is corresponding with the 1D system, is called two dimension (2-dimensional, 2D) weight.

Other users' interference, (parallel interferencecancellation, PIC) associating iterative scheme carries out multi-user interference and eliminates can to pass through MMSE-frequency domain equalization and parallel interference cancellation.Because once-through operation can not be eliminated remaining multi-user interference fully, therefore need carry out the iteration of several times, up to enough little of MAI.Its iterative process such as Fig. 4 are to shown in Figure 7.Introduce the setting of iterative initial value below.

When carrying out iterative detection, iterative initial value be set with dual mode, referring to Fig. 4 and Fig. 5, first kind of mode is to adopt two-dimentional least mean-square error to detect the weight that changes described frequency-region signal to obtain:

Iterative initial value (i=0) is determined by the frequency domain equalization weight factor of 2D-MMSE.Other users' interference signal

K=0～N _c-1; Decision signal after u '=0～U-1 ≠ u} is adjudicated by primary iteration is modulated spread spectrum again and is produced.When (i-1) inferior iteration, received signal becomes:

$R_{m,u}^{\&prime;\left(i\right)}\left(k\right)=R_m\left(k\right)-\sqrt{\frac{{2E}_c}{T_c}}\underset{u^{\&prime;}=0\&NotEqual;u}{\overset{U-1}{\mathrm{\&Sigma;}}}{H}_{m,u^{\&prime;}}\left(k\right)\&CenterDot;{\tilde{S}}_{u^{\&prime;}}^{(i-1)}\left(k\right)---\left(13\right)$

Since this moment other interference signals, by from whole received signal R _m(k) deduct in, admittedly can think

The frequency domain equalization computing of back (i 〉=1) becomes single user and transmits received signal, so will no longer be adopted the 2D-MMSE weight coefficient, and adopt traditional 1D-MMSE weight coefficient, shown in (14).

$R_u^{\&prime;\left(i\right)}\left(k\right)=w_u^{\&prime;\left(i\right)}\left(k\right)R_u^{\&prime;\left(i\right)}\left(k\right)---\left(14\right)$

Wherein With

Be respectively

With

Weight factor is shown in (15).

$w_u^{\&prime;\left(i\right)}\left(k\right)=H_u^H\left(k\right)\&lsqb;{H\left(k\right)H}^H\left(k\right)+{\left(\frac{C\&CenterDot;E_c}{N_0}\right)}^{-1}{I}_{{\mathrm{SF}}_t}{\&rsqb;}^{-1}---\left(15\right)$

That is, iterative initial value carries out the frequency domain equalization acquisition by the weight of formula (15), and iteration adopts the described one dimension least mean-square error of formula (14) to carry out the frequency domain equalization acquisition after reaching for the second time.

Second kind of obtain manner of iterative initial value referring to Fig. 6 and Fig. 7, carries out frequency domain equalization by the signal that produces after the piece despreading and obtains.

At SF _tChannel gain remains unchanged in the individual continuous block, i.e. h _u(τ) ≈ h _{M, u}(τ), (m=0～SF _t-1)), obtains the decision-feedback signal of initial (i=0) iteration.Piece despreading direct-type (16), simulation curve as shown in Figure 8, the error rate is good.

$r_u\left(t\right)=\frac{1}{{\mathrm{SF}}_t}\underset{m=0}{\overset{{\mathrm{SF}}_t-1}{\mathrm{\&Sigma;}}}{r}_m\left(t\right){\left\{c_u^{{\mathrm{SF}}_t}\left(m\right)\right\}}^{*}--\left(16\right)$

The output signal on every road is through extracting the multi-user interference signal (MAI) on this road after the inverse transformation, every road iterative value deducts the multi-user interference signal on other all roads, and its MAI is enough little until detecting, and is in reasonable level and finishes.Finish the parallel interference cancellation, the associating iterative scheme.Like this, residual multi-user interference can be very little.

Claims (8)

1. based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 5, the processing that step 4 is obtained carries out fast fourier transform, obtains frequency-region signal after the conversion;

Step 6, the frequency-region signal that step 5 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 the back signal as iterative initial value;

Step 7, the U road iterative initial value that step 6 is obtained carry out invert fast fourier transformation respectively, time-domain signal after the acquisition U road conversion;

Time-domain signal carries out the chip-level despreading respectively after step 8, the U road conversion that step 7 is obtained, obtains signal after the U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

2. according to claim 1 based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, step 9 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out the piece spread spectrum, obtains the signal behind the piece spread spectrum;

Signal behind step 4, the piece spread spectrum that step 3 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

3. based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

Signal after step 6, the processing 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 the back signal as iterative initial value;

Step 8, the U road iterative initial value that step 7 is obtained carry out chip-level despreading and deinterleaving respectively, signal after the acquisition U road despreading;

Signal demodulation after step 9, the U road despreading that step 8 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 10, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

4. according to claim 3 based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, step 9 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum and interweaves after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out invert fast fourier transformation, obtains time-domain signal;

Step 4, the time-domain signal that step 3 is obtained carry out the piece spread spectrum, the signal behind the acquisition piece spread spectrum;

Signal behind step 5, the piece spread spectrum that step 4 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

5. based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, under the SC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively, 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 the piece spread spectrum respectively, 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, 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 protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

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

Step 7, the frequency-region signal that step 6 is obtained carry out based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

6. according to claim 5 based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, step 10 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out the piece spread spectrum, obtains the signal behind the piece spread spectrum;

Signal behind step 4, the piece spread spectrum that step 3 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

7. based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, under the MC-CDMA system:

Emission process:

Step 1, U road modulation signal is carried out the chip-level spread spectrum respectively 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 invert fast fourier transformation respectively, obtains time-domain signal after the U road conversion;

Time-domain signal carries out the piece spread spectrum respectively 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 protection respectively to be handled at interval, the U road signal after obtaining to handle, and by transmission antennas transmit to channel;

Receiving course:

Step 5, employing reception antenna connect the U road signal of step 4 emission, and go protection to handle at interval the signal that receives, the signal after acquisition is handled;

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

U road signal after step 7, the processing that step 6 is obtained carries out fast fourier transform, obtains the U road signal of frequency domain after the conversion;

Step 8, the frequency-region signal that step 7 is obtained carry out changing the weight of described frequency-region signal based on one dimension least mean-square error frequency domain equalization, obtain the U road and detect the back signal as iterative initial value;

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

Signal demodulation after step 10, the U road despreading that step 9 is obtained, and extract U road multi-user interference signal respectively, duplicate to other U-1 roads, be used for parallel other users' of elimination interference;

Step 11, the employing one dimension mean square error of passing through detect the weight of change frequency domain equalization as the later iterative value second time, and carry out repeatedly iterative detection of every road signal, the multi-user interference signal that extracts until this road reaches reasonable level, and promptly the output error rate of twice iteration in front and back is less than 10 ^-5Magnitude is exported this circuit-switched data then,

U is a positive integer.

8. according to claim 7 based on the residual multi-user interference inhibition method in the two-dimensional block spread spectrum system of parallel interference cancellation and iterative detection, it is characterized in that, step 10 is extracted U road multi-user interference signal, and the acquisition process of wherein any one tunnel multi-user interference signal is:

Step 1, the output signal on every road is modulated, obtain modulation back signal;

Signal carries out the chip-level spread spectrum and interweaves after step 2, the modulation that step 1 is obtained, obtains signal behind the chip-level spread spectrum;

Signal behind step 3, the chip-level spread spectrum that step 2 is obtained carries out invert fast fourier transformation, obtains time-domain signal;

Step 4, the time-domain signal that step 3 is obtained carry out the piece spread spectrum, the signal behind the acquisition piece spread spectrum;

Signal behind step 5, the piece spread spectrum that step 4 is obtained carries out fast fourier transform, obtains the multi-user interference signal on this road.

Images