CN101388677A - Interference resisting method for communication receiver based on blind signal separation and system thereof - Google Patents

Abstract

The invention discloses a communication receiver anti-interference method on the basis of blind signal separation and a system thereof, wherein the method comprises: utilizing a positive-negative 45 degree dual polarization antenna module to receive signals, changing a two way high frequency signal into an intermediate frequency analog signal, outputting an intermediate frequency digital signal by the intermediate frequency analog signal through analogue/digital conversion and after an orthogonal transformation module, then, carrying out digital down conversion, abstracting, filtering, and the like, transforming into a DSP baseband complex signal, obtaining a statistical independent signal after two ways are separated by the complex signal after passing through a linear blind signal separation algorithm module, carrying out self-adaptive equalization processing to a two way estimating signal after blind separation, counteracting crosstalk in a communication channel, utilizing a known modulation and demodulation method to demodulate a two way independent signal, analyzing a two way signal, and abstracting a useful signal. The invention does not need to use any other reference signals, adopts the linear blind signal separation algorithm to estimate the two way independent separation signal, the calculation complexity is low, and the disturbance to the communication receiver under the condition of low signal-to-noise ratio can be eliminated.

Description

Interference resisting method for communication receiver and system thereof based on Blind Signal Separation

Technical field

The present invention relates to the communication technology, specifically is a kind of interference resisting method for communication receiver and system thereof based on Blind Signal Separation, by this The Application of Technology, can effectively eliminate interference, improve the quality of communication.

Background technology

It is the famous cocktail party problem (CPP, cocktail partyproblem) that Colin Cherry proposes that blind signal processing originates from the earliest, refers in noisy environment, and the mankind have the outstanding ability that can note and identify one of them sound source.And along with the latest development of blind signal separation technology, the cocktail party problem has had various better solution.In recent years, blind signal processing research had become the noticeable hot issue in signal processing field.Blind Signal Separation is an importance of blind signal processing, be meant under the situation of the parameter of not knowing source signal and transmission channel, only come identification system, reaching purpose, thereby recover primary signal or signal source a plurality of Signal Separation by the output signal that observes.Undoubtedly, it can provide great convenience to the many signal processing and the identification of wide spectrum.

Blind Signal Separation is one of emerging research direction popular in the current demand signal process field, and it has the application potential of reliable theoretical basis and many aspects.Many Blind Signal Separation algorithms had been proposed in the last few years in the world, wherein more famous have a Jade algorithm, the FastICA algorithm, InfoMax algorithm and blind deconvolution algorithm etc., its application comprises the voice signal processing, the biological field signal processing, picture signal is handled, signal of communication processing etc.

Along with development of Communication Technique; wireless communication system has obtained using widely in military-civil communication; simultaneously; because communication environment is complicated; also have higher requirement for Anti-Jamming Technique, the validity of Anti-Jamming Technique and stability directly influence the transmission quality of communication and the protection of information.

In digital wireless communication, how to make full use of limited frequency band, serving client as much as possible, is an important problem all the time. and anti-interference be that it medium-term and long-term is the theoretical problem of being paid much attention to the engineering worker, also produced multiple communication Anti-Jamming Technique thus.Code division multiple access (CDMA) technology is by the pseudorandom source encoding, in narrow band signal power expansion to a broadband, to improve signal noise ratio, strengthens the communication system antijamming capability.In addition, also have some to utilize fast frequency-hopped technology to hide the communication mode of interference, also can improve communication quality to a certain extent.Recent achievement in research has proposed employing antenna array receiving system and space filtering, the difference of the signal that utilization receives by the Blind Signal Separation algorithm, is implemented in the same channel separation to multi-user's signal, thereby realize anti-interferencely, improve communication quality greatly.

The defective of prior art:

Under desirable channel situation, the vector that the antenna array received signal constitutes can be similar to the linear hybrid of only regarding as by each source signal, therefore each element of hybrid matrix is constant, can realize that signal is anti-interference by the method that the cochannel multiple user signals carries out linear blind separation.But radio communication channel for reality, each element of hybrid matrix can not be regarded constant again as, received signal might be the convolution aliasing, there is intersymbol interference, in this case, adopting linear Blind Signal Separation method to carry out jamproof effect will be affected, if but adopt the blind deconvolution technology, on algorithm complex and amount of calculation, also not very real on existing techniques in realizing no matter.

In the disturbance restraining method of announcing at present based on blind separation, the Blind Signal Extraction device of in the prospectus of patent CN101034900A, mentioning by Civil Aviation University of China, for Receiver Module, wherein mention and utilize double antenna to receive two-way very high frequency(VHF) signal, carry out follow-up processing then, it is to be noted in this and utilize double antenna to receive two-way very high frequency(VHF) signal, putting of double antenna is to reach necessarily required, if the double antenna Position Design is unreasonable, what probably cause receiving is the identical aliasing signal of two-way, makes follow-up Blind Signal Separation become pathological situation.And the antenna putting position has limited the flexible Application of receiver.

Summary of the invention

The object of the present invention is to provide a kind of interference resisting method for communication receiver based on Blind Signal Separation of tackling when having interference signal in the communication process, utilization realizes separation signal based on the blind disjunctive model of linear instantaneous aliasing, realization realizes Adaptive Anti-jamming to the interference source or the noise source of arbitrary form unknown in the signal of communication, improves communication quality.

Another object of the present invention is to provide a kind of communication control processor jamproof system based on Blind Signal Separation.

A kind of interference resisting method for communication receiver based on Blind Signal Separation may further comprise the steps:

(1) utilize the dual polarized antenna array module to receive signal;

(2) the two-way high-frequency signal is converted to analog intermediate frequency signal;

(3) analog intermediate frequency signal is exported digital intermediate frequency signal after by analog-to-digital conversion and orthogonal transform module;

(4) carry out Digital Down Convert, extract, be converted to the DSP baseband complex signal after the filtering;

(5) complex signal obtains the statistics independent signal after two-way separates after by the Blind Signal Separation module;

(6) to removing channel disturbance by adaptive balance module through the statistics independent signal of separating after the step (5);

(7) two paths of signals is carried out the demodulation judgement, extract wherein one road signal.

Further, the described dual polarized antenna array module of step (1) is positive and negative 45 degree dual polarized antenna array modules, thereby makes the two paths of signals that receives not quite identical, satisfies the primary condition of blind separation, make aliasing matrix full rank, can effectively avoid the ill-conditioning problem in the blind separation.

Further, described Blind Signal Separation module is carried out linear blind signal separation to complex signal, to obtain two statistics independent signals mutually.Linear blind signal separation speed is fast, and computation complexity is low with respect to blind deconvolution, is applicable to Project Realization.

Further, step (7) is at first carried out demodulation to two paths of signals, and then by frame head data and signal characteristic, judgement wherein one road signal is that signal of communication, another road signal are noise signal, extracts signal of communication wherein then.

It is described that two paths of signals is carried out demodulation is that two paths of data is simultaneously carried out matching demodulation according to the known modulation system that transmit leg and reciever are appointed, judge according to the feature and the frame head information of known signal of communication then, the useful communication sources signal that definite recovery is come out is done follow-up terminal processes then.

A kind of communication control processor jamproof system based on Blind Signal Separation comprises successively:

Double polarized antenna mould----is used to receive high frequency analog signals;

Analog-to-digital conversion and orthogonal transform module----are used for the two-way analog intermediate frequency signal is converted to digital intermediate frequency signal;

Digital Down Converter Module----is used for digital intermediate frequency signal is converted to the DSP baseband complex signal;

Blind Signal Separation module----is used to separate the two-way aliasing signal;

Self application balance module----is used to remove channel disturbance;

Reconciling judging module----is used for signal is mediated and adjudicated wherein signal of communication;

And D/A converter module and signal output module.

Described analog-to-digital conversion group and orthogonal transform module realize that under a chip AD9862 Digital Down Convert is realized by the Digital Down Convert IP kernel cell design of FPGA.

Jamproof Blind Signal Separation method of communication of the present invention and system thereof, the Blind Source that not only is applicable to two paths of signals is separated, can also be by adjusting aerial array, receive by many antennas, realize the Blind Signal Separation of multiple signals, by to reception antenna and through behind the signal processing modules such as a series of analog-to-digital conversion and Digital Down Convert, on the Blind Signal Separation algorithm, utilize the statistical independence of signal, signal is carried out blind separation, the final inhibition that realizes a plurality of interference signals improves the quality of communication.

The present invention has following characteristics:

(1) the present invention utilizes the Antenna Design technology to realize that many antennas of two paths of signals receive, and obtains the not quite identical aliasing signal of two-way, satisfies the primary condition of aliasing matrix full rank in the Blind Signal Separation, avoids occurring the pathological situation in the Blind Signal Separation.

(2) the present invention need not any reference signal, only need be to the modulation system of known useful signal, separate the corresponding demodulation mode of timing utilization and frame head information in blind separation and wait which is the estimated signal of useful signal in the signal after judging separation, remove interference signal.

What (3) the present invention adopted is the technology of linear Blind Signal Separation, is far smaller than the blind deconvolution isolation technics on complexity and amount of calculation, is applicable to Project Realization, can effectively suppress any interference signal simultaneously.

(4) be linear blind isolation technics owing to what adopt,, realize the recovery of signal so, behind blind separation module, add adaptive balance module in order to resist the convolution intersymbol interference in transmission channel.

The present invention is practical, can be used for the anti-interference of signal of communication and separates the system that the multichannel movable signal interferes with each other, and improves communication quality.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is based on the basic hardware frame diagram of the communication control processor jamproof system of Blind Signal Separation;

Fig. 3 is the Blind Signal Separation algorithm flow chart;

Fig. 4 is a signal demodulation judging module structural representation;

Fig. 5 is known source signal planisphere;

Fig. 6 is the random disturbances signal constellation which;

Fig. 7 is the road aliasing signal that emulation receives;

Fig. 8 is another road aliasing signal that emulation receives;

Fig. 9 is through road independent signal planisphere behind the Blind Signal Separation algorithm;

Figure 10 is through another road independent signal planisphere behind the Blind Signal Separation algorithm;

Figure 11 one road aliasing signal does not directly carry out the signal constellation which of adaptive equalization through Blind Signal Separation;

Figure 12 is another Lu Yilu aliasing signal does not directly carry out adaptive equalization through Blind Signal Separation a signal constellation which;

Figure 13 is wherein one road signal constellation which through Blind Signal Separation and adaptive balance module;

Figure 14 is other one road signal constellation which through Blind Signal Separation and adaptive balance module.

Embodiment

Below in conjunction with accompanying drawing the present invention is done explanation in further detail, transmitter and receiver both sides' the modulation demodulation system of arranging to know clearly among the present invention.

Fig. 1 is based on the structural representation of the communication control processor jamproof system of Blind Signal Separation, by this system interference signal source is effectively suppressed, and improves communication quality.As shown in Figure 1, comprise two antenna array module, radiofrequency signal receiver module, analog-to-digital conversion and orthogonal transform module, Digital Down Converter Module, Blind Signal Separation algoritic module, adaptive balance module, demodulation and judging module, D/A converter module, signal outlet terminal module successively.

Based on the anti-interference method of the communication control processor of Blind Signal Separation, concrete steps are as follows:

The first step: communicate the reception of signal by antenna, obtain the signal behind the two-way aliasing, because in blind separation theorem the inside, for the ill-conditioning problem way that also is not well solved, and actually, algorithm at ill-conditioning problem is difficult to realize, so, the present invention utilizes positive and negative 45 degree dual polarized antennas to carry out signal and receives, making resultant two-way aliasing signal is the signal that useful signal and interference signal obtain through linear aliasing, this two-way aliasing signal is not quite identical, meets the blind separation basic demand of aliasing matrix full rank, for the following Blind Signal Separation algoritic module of doing provides assurance;

Second step: because the two paths of signals that receives is the analog signal of high frequency, so will obtain the analog signal of intermediate frequency through analog down;

The 3rd step: the analog signal of intermediate frequency is in process analog to digital conversion module and orthogonal transform module, obtain two-way orthogonal digital intermediate-freuqncy signal, wherein, analog to digital conversion and orthogonal transform realize in the AD9862 chip simultaneously, its two ways of digital signals bit wide all is 12bit respectively, the digital intermediate frequency signal that obtains is not suitable for DSP and handles because frequency is very high, so will be implemented to the base band signal process of DSP through following step;

The 4th step: digital intermediate frequency signal after extraction and the filtering, obtains the baseband digital signal of low speed through Digital Down Convert.Digital down converter (DDC) fades to baseband digital signal with digitized intermediate-freuqncy signal, obtains I, the Q data of quadrature, so that carry out base band signal process.Digital down converter (DDC) mainly is made up of DDS, comb filter CIC, compensation low pass filter CFIR and low pass filter PFIR.The conversion using comb filter CIC that realizes signal input and output sample rate changes, utilize the compensation CFIR filter that freely to select among the DDC to realize the compensation that comb filter is decayed then, utilize low pass PFIR filter to solve the signal aliasing problem that occurs in the middle of the mixing again, Digital Down Convert DDC utilizes the IP kernel among the FPGA to design among the present invention;

The 5th step: by the I of the 4th two baseband digital signals obtaining of step, Q two-way base band data is input to the separation that DSP carries out Blind Source, and the separation of Blind Source realizes as distinguishing rule according to the statistical independence feature of source signal.In the process of the signal convolution aliasing of common described signal of communication in transmission course, because blind uncoiling exists problems such as complexity height, amount of calculation are big in theoretical and algorithm research, on Project Realization, very high requirement is proposed for the arithmetic speed of hardware processor and the amount of calculation of algorithm etc., so, on Project Realization, the present invention has carried out some to above-mentioned model and has simplified, and wishes the selection by simplified models and method, makes the blind separation of signal of communication be able to realize on engineering.Be to describe signal s below ₁, s ₂Transmission course.Resulting baseband signal z ₁, z ₂For:

$z_1\left(t\right)=a_{11}\underset{i=0}{\overset{L_{k1}}{\mathrm{\Σ}}}{h}_{11i}{s}_1(t-i)+a_{21}\underset{i=0}{\overset{L_{k2}}{\mathrm{\Σ}}}{h}_{22i}{s}_2(t-i)$

$z_2\left(t\right)=a_{12}\underset{i=0}{\overset{L_{k1}}{\mathrm{\Σ}}}{h}_{11i}{s}_1(t-i)+a_{22}\underset{i=0}{\overset{L_{k2}}{\mathrm{\Σ}}}{h}_{22i}{s}_2(t-i)$

Wherein s is a source signal, a _Ij(i, j=1,2) are the aliasing parameter, h _11i, h _22iBe channel parameter, L _K1, L _K2Be intersymbol interference length, z is the signal behind the aliasing, and this simplified model is suitable under the simple relatively situation of channel, can avoid realizing that the data volume of blind deconvolution is big on engineering, the shortcoming that complexity is high.

Following formula can be write as matrix form, z=As, and wherein s has temporarily ignored delay parameter, delay issue obtains handling in next step adaptive channel equalizer, for formula z=As, what Blind Signal Separation was considered is to seek a transformation matrix W, makes y=Wz=WAs make y similar to s.

For z=As, at first z is carried out albefaction

z＝Qz _old

Wherein zold is the aliasing signal that observes, and z is the signal after the albefaction, and behind albefaction battle array Q, the whitened signal z that obtains satisfies E{zz ^H}=I, albefaction realizes by principal component analysis.

Utilize plural FastICA algorithm to find the solution separation matrix W then, method for solving utilizes following iterative formula to derive and obtains:

w ⁺＝E{x(w ^Hx)*g(w ^Hx)}-E{g(w ^Hx)}+|w ^Hx| ²g′(|w ^Hx| ²)}w

$w_{\mathrm{new}}=\frac{w^{+}}{\left|\right|w^{+}\left|\right|}$

After finding the solution the W matrix that obtains, the estimated signal of the source signal after can obtaining separating by y=Wx, concrete Blind Signal Separation algorithm flow chart is as shown in Figure 3.

The 6th step: because what obtain through top Blind Signal Separation only is signal after separating, said suddenly as previous step, the time-delay cross-interference issue of having ignored signal, and in the wireless transmission of broadband high-speed, because multiple influences such as multipath, time delay expansion, decline, symbol timing offset, intersymbol interference (ISI) is the serious problems that can not ignore, and an approach that addresses this problem is to adopt adaptive equalization, and this is to make big system after it and the channel cascaded have unit impulse to respond and realize.So, after the separation signal that obtains above, need to realize the equilibrium of channel through Technology of Adaptive Equalization.The present invention adopts decision-feedback adaptive equalization technique (DFE), because the RLS algorithm has convergence rate faster with respect to the LMS algorithm, so the judgment feedback balance technique iterative algorithm is realized by the RLS algorithm in the present invention.

Adaptive decision feedback equalizer DFE structrual description is as follows:

$x\left(k\right)=\underset{i=0}{\overset{\mathrm{Nh}-1}{\mathrm{\Σ}}}h\left(i\right)*s(k-i)+n\left(k\right)$

y(k)＝f ^T(k)X(k)

$v\left(k\right)=b^T\left(k\right)\hat{s}\left(k\right)$

$z\left(k\right)=y\left(k\right)-v\left(k\right)=\underset{i=0}{\overset{\mathrm{Nf}-1}{\mathrm{\Σ}}}f\left(k\right)x(k-i)-\underset{i=0}{\overset{\mathrm{Nb}-1}{\mathrm{\Σ}}}b\left(k\right)\hat{s}(k-i)$

Wherein x (k) is the received signal through channel h (i), and f is a feedforward filter, and b is a feedback filter,

Be prediction signal, z is through the output signal after the DFF.For feedforward filter and rear feed filter coefficient, adopt the RLS algorithm iteration to find the solution.

The 7th step: the demodulation of signal and judge useful information source, the known modulation system that the present invention needs transmitting terminal and receiving terminal to appoint, receiving terminal is through after a series of processing, obtained the two-way separation signal, for the signal after two-way process Blind Signal Separation and the adaptive equalization, use the modulation system of appointing to carry out corresponding demodulation simultaneously, in order to reduce interference signal is carried out too much processing, need on useful signal, utilize frame head data to realize differentiating, to determine that wherein one road signal is a useful signal, continue then it is carried out relevant treatment, as shown in Figure 4.

Fig. 2 is the hardware structure figure of jamproof Blind Signal Separation method of communication of the present invention and system model thereof, and Fig. 5～14 have provided the simulate signal planisphere at described interference resisting method for communication receiver based on the Blind Signal Separation method.Fig. 5 is known source signal planisphere; Fig. 6 is the random disturbances signal constellation which; Fig. 7 is the road aliasing signal that emulation receives; Fig. 8 is another road aliasing signal that emulation receives; Fig. 9 is through road independent signal planisphere behind the Blind Signal Separation algorithm; Figure 10 is through another road independent signal planisphere behind the Blind Signal Separation algorithm; Figure 11 one road aliasing signal does not directly carry out the signal constellation which of adaptive equalization through Blind Signal Separation; Figure 12 is another Lu Yilu aliasing signal does not directly carry out adaptive equalization through Blind Signal Separation a signal constellation which; Figure 13 is wherein one road signal constellation which through Blind Signal Separation and adaptive balance module; Figure 14 is other one road signal constellation which through Blind Signal Separation and adaptive balance module.Wherein the aliasing process is that the signal interference ratio of source signal and interference signal is-10dB that channel is crosstalked, and contains small amount of noise.Wherein the ordering uncertainty has appearred in the signal through Blind Signal Separation and adaptive balance module, need judge in the demodulation judgement.Pass through the processing of Blind Signal Separation module as can be seen from Fig. 5～14, the quality of reception is significantly improved.

Claims (5)

1, a kind of interference resisting method for communication receiver based on Blind Signal Separation may further comprise the steps:

(1) utilize the dual polarized antenna array module to receive signal;

(2) the two-way high-frequency signal is converted to analog intermediate frequency signal;

(3) analog intermediate frequency signal is exported digital intermediate frequency signal after by analog-to-digital conversion and orthogonal transform module;

(4) carry out Digital Down Convert, extract, be converted to the DSP baseband complex signal after the filtering;

(5) complex signal obtains the statistics independent signal after two-way separates after by the Blind Signal Separation module;

(6) to removing channel disturbance by adaptive balance module through the statistics independent signal of separating after the step (5);

(7) two paths of signals is carried out the demodulation judgement, extract wherein one road signal.

2, the interference resisting method for communication receiver based on Blind Signal Separation according to claim 1 is characterized in that: the described dual polarized antenna array module of step (1) is positive and negative 45 degree dual polarized antenna array modules.

3, the interference resisting method for communication receiver based on Blind Signal Separation according to claim 1 and 2 is characterized in that: the described Blind Signal Separation module of step (5) is carried out linear blind signal separation to complex signal, to obtain two statistics independent signals mutually.

4, the interference resisting method for communication receiver based on Blind Signal Separation according to claim 3, it is characterized in that: described step (7) is at first carried out demodulation to two paths of signals, then by frame head data and signal characteristic, judgement wherein one road signal is that signal of communication, another road signal are noise signal, extracts signal of communication wherein then.

5, a kind of communication control processor jamproof system based on Blind Signal Separation is characterized in that comprising successively:

Double polarized antenna mould----is used to receive high frequency analog signals;

Analog-to-digital conversion and orthogonal transform module----are used for the two-way analog intermediate frequency signal is converted to digital intermediate frequency signal;

Digital Down Converter Module----is used for digital intermediate frequency signal is converted to the DSP baseband complex signal;

Blind Signal Separation module----is used to separate the two-way aliasing signal;

Self application balance module----is used to remove channel disturbance;

Reconciling judging module----is used for signal is mediated and adjudicated wherein signal of communication;

And D/A converter module and signal output module.

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