CN101651463B - Method and device for suppressing narrowband interference of baseband signals - Google Patents

Method and device for suppressing narrowband interference of baseband signals Download PDF

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CN101651463B
CN101651463B CN2008101183502A CN200810118350A CN101651463B CN 101651463 B CN101651463 B CN 101651463B CN 2008101183502 A CN2008101183502 A CN 2008101183502A CN 200810118350 A CN200810118350 A CN 200810118350A CN 101651463 B CN101651463 B CN 101651463B
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CN101651463A (en
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陈永倩
孙建勋
裴亚丽
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Datang Mobile Communications Equipment Co Ltd
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Abstract

The invention discloses a method and a device for suppressing narrowband interference of baseband signals. The method comprises the following steps: acquiring the baseband signals of received signals after passing through a pulse shaping filter; carrying out fast Fourier transform for the baseband signals to acquire frequency domain signals of the received signals; filtering frequency point signals in a pass band, a transition band and a stop band of the pulse shaping filter in the frequency domain signals according to the frequency response chrematistics of the pulse shaping filter respectively; and carrying out inverse fast Fourier transform for the filtered frequency domain signals to acquire the baseband signals of the received signals. Compared with the narrowband interference suppression algorithm which adopts an identical threshold and an identical processing method in the prior art, the method and the device after implementation can improve the narrowband interference suppression capacity of a communication system.

Description

A kind of inhibition method and device of baseband signal narrow band interference
Technical field
The present invention relates to Communication Jamming inhibition technology, particularly a kind of inhibition method and device of baseband signal narrow band interference.
Background technology
DSSS (Direct Sequence Spread Spectrum, DSSS) system is one of spread spectrum principal mode in practical application.Strong anti-interference performance not only, communication security is good, and Project Realization is simple relatively, therefore is widely used in military field, satellite communication and digital mobile communication system etc.Along with the electronic technology develop rapidly, frequency spectrum resource is deficient day by day, and aerial electromagnetic environment also constantly worsens, and the interference free performance of DSSS system is had higher requirement.Especially in following military struggle field, the strong narrow band interference of enemy's malice tends to the jamming margin of the system that breaks through, causes system decreased performance even malfunctioning.Therefore be necessary before the signal despreading, to adopt the corresponding signal process technology, suppress to disturb, improve systematic function.
In recent years, very active always around the research of spread spectrum communication interference mitigation technology, number of research projects is paid close attention to effectively exploitation, utilization and the development of Suppression of narrow band interference technology in the spread spectrum system always.The implementation method of interference mitigation technology is a lot, specifically comprises time-domain adaptive filtering interference mitigation technology and transform domain interference mitigation technology.Wherein time-domain adaptive filtering comprise prediction estimation filter and decision feedback filter device, all be to utilize the correlation of narrow band interference by force to realize inhibition a little less than the correlation of spread-spectrum signal to narrow band interference.For adaptive-filtering.The Nonlinear Processing technology is more effective than linear technique.Nonlinear function is introduced into filter and constitutes the nonlinear filtering system, and evolution algorithm and neural network algorithm also are introduced into the stability that is used to improve the nonlinear filter system.The adaptive-filtering of time domain is handled has Suppression of narrow band interference ability completely, but convergence rate is unhappy, relatively is suitable for handling the narrow band interference that becomes slowly.The transform domain interference mitigation technology is used to offset single-frequency, multifrequency and narrow band interference: can be divided into DFT (Discrete Fourier Transform; DFT), DCT (Discrete Cosine Transform; Discrete cosine transform), ST (SubBand Transform; Sub-band transforms), WPT (wavelet packet transform, wavelet package transforms) etc.Along with FFT (Fast Fourier Transform, FFT) appearance of algorithm and developing rapidly of large-scale circuit, make many conversion be able to real-time implementation, so the transform domain treatment technology become interference inhibition hot research fields.
In most spread spectrum communication systems, have only the strong especially narrow band interference of minority to have a strong impact on systematic function.And in spread spectrum communication, the ratio of the strong shared whole broadband of narrow band interference frequency range is very low.If with the target signal filter of these frequency ranges, then strong narrow band interference will obtain good restraining, and the spread-spectrum signal power loss is very little.Transform domain Suppression of narrow band interference filter just is based on spread-spectrum signal and this characteristics design of narrow band interference on frequency domain.
Fig. 1 is transform domain Suppression of narrow band interference filter basic structure sketch map, and is as shown in Figure 1, receives signal x (k) and transforms to frequency domain through FFT.Each frequency and interference suppression filter corresponding points multiply each other, and are multiplied by frequency domain filter coefficient { W respectively i, disturb inhibition through the output of IFFT (Inverse Fast Fourier Transform, invert fast fourier transformation) back, thereby realize the inhibition of narrow band interference.
In order to suppress narrow band interference to greatest extent, make the performance loss of communication system minimum simultaneously, Filter Design is very crucial.In common algorithm, be mostly a frequency-region signal and a thresholding are compared, be lower than the reservation of thresholding, surpass the Filtering Processing of carrying out of thresholding.Generally speaking, the selection of thresholding has considered to receive whole frequency signals of signal, and adopts same thresholding to carry out filtering for all frequency signals, just to received signal all frequency signals processing method of making no exception.
The deficiency of prior art is: when the processing method of making no exception by prior art all frequency signals to received signal, promptly adopt same thresholding to come the method for filtering narrow band interference can not make the Suppression of narrow band interference ability of system reach best.
Summary of the invention
The technical problem that the present invention solves has been to provide a kind of inhibition method and device of baseband signal narrow band interference, in order to improve the inhibition ability to the baseband signal narrow band interference.
The present invention provides a kind of inhibition method of baseband signal narrow band interference in an embodiment, comprises the steps:
Obtain and receive the baseband signal of signal after passing through the pulse-shaping filter;
Baseband signal is obtained the frequency-region signal of received signal after FFT;
Confirm the impulse Response Function of pulse-shaping filter according to the reception signals sampling cycle;
Confirm the transfer function of the impulse Response Function of pulse-shaping filter;
It is frequency signal, the frequency signal in the transition band and the frequency signal in the stopband in the pulse-shaping filter passband that the Frequency Response of confirming according to above-mentioned transfer function confirms to receive the signal frequency-domain signal, and the frequency signal in the above-mentioned pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band are carried out filtering respectively;
Filtered frequency-region signal is obtained to receive the baseband signal of signal behind invert fast fourier transformation.
The present invention also provides a kind of restraining device of baseband signal narrow band interference in an embodiment, comprising:
Acquisition module is used to obtain the baseband signal of reception signal after passing through the pulse-shaping filter;
Conversion module is used for baseband signal is obtained to receive the signal frequency-domain signal after FFT;
Filtration module is used for confirming the impulse Response Function of pulse-shaping filter according to receiving the signals sampling cycle; Confirm the transfer function of pulse-shaping filter impulse Response Function; The Frequency Response of confirming according to said transfer function is confirmed frequency signal, the frequency signal in the transition band and the frequency signal in the stopband in the pulse-shaping filter passband in the frequency-region signal, and the frequency signal in the said pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band are carried out filtering respectively;
Inverse transform module is used for filtered frequency-region signal is obtained to receive the baseband signal of signal behind invert fast fourier transformation.
Embodiment of the invention beneficial effect is following:
The present invention has taken into full account the spectral characteristic of signal through the received pulse formed filter in implementing; Promptly; During the frequency-region signal that after the FFT conversion, obtains in baseband signal; To receive the signal frequency-domain signal distinguishing according to the pulse-shaping filter response is the frequency signal in the pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band; And adopt different threshold to suppress narrow band interference with different treating methods to the frequency range of signal, that is, the frequency signal in the paired pulses formed filter passband, the frequency signal in the transition band and the frequency signal in the stopband are set thresholding respectively and are carried out filtering; Compare with the Suppression of narrow band interference algorithm of same thresholding of available technology adopting and same treating method, can improve the Suppression of narrow band interference ability of communication system after the present invention implements.
Description of drawings
Fig. 1 is the filter of transform domain Suppression of narrow band interference described in a prior art basic structure sketch map;
Fig. 2 is the inhibition method implementing procedure sketch map of baseband signal narrow band interference described in the embodiment of the invention;
Fig. 3 is that input described in the embodiment of the invention is implemented sketch map;
Fig. 4 is the restraining device structural representation of baseband signal narrow band interference described in the embodiment of the invention.
Embodiment
Describe below in conjunction with the accompanying drawing specific embodiments of the invention.
Because mobile telecommunication channel is typical bandwidth efficient channel, in order to suppress intersymbol interference, GSM has all adopted the pulse-shaping filter in the sending and receiving end.Receive signal through the pulse-shaping filter that receives after, the frequency signal that receives signal just can be divided into frequency signal in the pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band according to the pulse-shaping filter response.And the intensity that is in the frequency signal in the different sections has very big difference, based on this, has proposed to be applicable to the Suppression of narrow band interference scheme of base band during the present invention implements.In solution; It is contemplated that: according to the characteristics of received pulse formed filter; Be divided into passband, transition band and stopband to the spectrum region that receives signal; And to the employing of the frequency signal in these 3 different frequency bands different threshold and different treating methods, thereby overcome the deficiency that only exists single thresholding to carry out filtering in the prior art, make that the effect that suppresses narrow band interference is better.
Fig. 2 is the inhibition method implementing procedure sketch map of baseband signal narrow band interference, and is as shown in the figure, when interference is suppressed, can comprise the steps:
Step 201, obtain and receive signal through the baseband signal behind the pulse-shaping filter;
Step 202, baseband signal is obtained to receive the signal frequency-domain signal after the FFT conversion;
Step 203, the frequency signal in the pulse-shaping filter passband in the frequency-region signal, frequency signal and the frequency signal in the stopband in the transition band are carried out filtering respectively according to the pulse-shaping filter response;
Step 204, filtered frequency-region signal obtained to receive the baseband signal of signal after the IFFT conversion.
Practical implementation in the face of each step describes down.
If the signal s (t) of DSSS system has sneaked into additive white Gaussian noise and narrow band interference in the Channel Transmission process, then receiving signal x (t) can be expressed as:
x ( t ) = s ( t ) + Σ l = 1 q i l ( t ) + n ( t ) - - - ( 1 )
Wherein, i l(t) be narrow band interference, uncorrelated each other between each narrow band interference; N (t) is a white Gaussian noise, and is all uncorrelated with signal and narrow band interference.
Then x (t) is sampled, during signal sampling, with variable be worth continuous analog signal all and successively convert on discrete signal discrete on the variable and value also discrete digital signal (quantifications) into, the discrete form of acquisition reception signal is:
x ( m ) = s ( m ) + Σ l = 1 q i l ( m ) + n ( m ) - - - ( 2 )
Jamproof purpose just is as far as possible to disturbing i l(m) suppress, so that correct recovering information sequence s (m).
Fig. 3 implements sketch map for input; As shown in the figure; In the signal detection process of the DSSS GSM that has added base band Suppression of narrow band interference device; Suppress to handle through carrying out the base band arrowband behind the pulse-shaping filter more earlier; Receive signal through the pulse-shaping filter that receives after, the frequency signal that receives signal just can be divided into frequency signal in the pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band according to the pulse-shaping filter response.
In the enforcement, at first in step 201, obtain and receive the baseband signal of signal after passing through the pulse-shaping filter; In step 202, baseband signal is obtained to receive the signal frequency-domain signal after the FFT conversion then, after obtaining frequency-region signal, just can execution in step 203, describe in the face of step 202,203 practical implementation down.
Pulse-shaping filter in the GSM generally adopts root raised cosine filter, and the example that is embodied as with root raised cosine filter describes below.Adopting root raised cosine filter among the embodiment mainly is that what to consider that the standard of existing 3G all adopts is root raised cosine filter; Therefore be that example describes with the root raised cosine filter; But those skilled in the art are prone to know; In the pulse-shaping filter, except root raised cosine filter, can be used for implementing so long as can suppress the pulse-shaping filter of intersymbol interference.
For root raised cosine filter, its impulse response RC 0(t) be:
RC 0 ( t ) = 2 α π T s sin ( ( 1 - α ) π t T s ) 4 α t T s + cos ( ( 1 + α ) π t T s ) ( 1 - ( 4 α t T s ) 2 ) - - - ( 3 )
Wherein, rolloff-factor α=0.22, T sFor receiving the signals sampling cycle.
If Z ( f ) = T s 0 ≤ | f | ≤ 1 - α 2 T s T s 2 { 1 + Cos [ π T s α ( | f | - 1 - α 2 T s ) ] } 1 - α 2 T s ≤ | f | ≤ 1 + α 2 T s 0 | f | > 1 + α 2 T s - - - ( 4 )
In the following formula, being that the Z transfer function of time frequency signal t is expressed, is variable with frequency f in the Z transfer function.So, the transfer function RC of root raised cosine filter 0(f) be:
RC 0(f)＝|Z(f) 1/2| (5)
Root raised cosine filter is the filter that satisfies the Nquist criterion, and it can overcome intersymbol interference fully, but because impulse response RC 0(t) be non-causal,, exist like this so it must brachymemma
Figure GSB00000918833800071
Those frequency spectrum points just no longer be zero.
The bandwidth of supposing the reception signal is that B is (common
Figure GSB00000918833800072
), according to the transfer function RC of root raised cosine filter 0(f) characteristics can be the frequency signal distinguishing that receives signal following 3 sections:
1), satisfies
Figure GSB00000918833800073
Those frequency signals be made as passband B pInterior point;
2), satisfy
Figure GSB00000918833800074
Those frequency signals be made as transition band B tInterior point;
3), satisfy
Figure GSB00000918833800075
Those frequency signals be made as stopband B sInterior point;
That is, in step 203, confirm that according to receiving the signals sampling cycle pulse-shaping filter is the impulse Response Function of variable with time; The impulse Response Function of confirming the pulse-shaping filter then is the transfer function of variable with the frequency; To receive the signal frequency-domain signal distinguishing according to the Frequency Response of confirming in the transfer function again is the frequency signal in the pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band; In the practical implementation, when carrying out segmentation, can confirm according to frequency signal, sampling period according to Frequency Response.
Because after the transfer function of pulse-shaping filter had been confirmed, just filtering characteristic was just definite for its frequency response characteristic so, was receiving signal through behind the pulse-shaping filter, the signal that is in different Frequency points just has different decay.Each filter all has passband, transition band and stopband; Signal to being in the different frequency bands passes through filter; The amplitude of signal just has very big difference after the filtering of coming out after the Filtering Processing; Also, utilized filter response will receive signal subsection in force, and carried out segmentation filtering based on this.
Know from above-mentioned, because the transfer function RC of root raised cosine filter 0(f) characteristics; The amplitude that is in the frequency signal in passband, transition band and the stopband has very big difference; Based on this, when the base band Suppression of narrow band interference is implemented, at first be; The baseband signal x (m) that passes through behind the pulse-shaping filter that will in step 201, receive does the FFT conversion in step 202, obtain to receive signal frequency-domain signal X (k) then.
After this in step 203, X (k) is divided into three sections, that part of X (k) in the pulse-shaping filter passband is made as X p(k),
Figure GSB00000918833800081
The part that is in accordingly in the transition band is made as X t(k), 1 - &alpha; 2 T s &le; k &le; 1 + &alpha; 2 T s ; Part in the stopband is X s(k), 1 + &alpha; 2 T s < k &le; B .
Threshold value when again three sections frequency-region signals being carried out Filtering Processing in step 203 is respectively below chosen and is carried out corresponding filtering and describes.
One, to X p(k) carry out Filtering Processing, that is, the frequency signal in the paired pulses formed filter passband is handled.
In the enforcement, the frequency signal sets thresholding in passband is: Th p=μ * M Av, wherein:
M AvAmplitude equalizing value for all the frequency signals in the passband; Specifically can use the intermediate value of this amplitude equalizing value as frequency signal in the passband, or, the frequency signal in the passband is divided into several portions; Calculate the average of amplitude of the frequency signal of each part respectively, get minimum average then as M Av
μ during according to proper communication the spectrum value of signal distribute and choose.μ is a discrepancy factor, and just the amplitude of frequency will be carried out filtering above amplitude intermediate value μ those frequencies doubly.Can being chosen in the enforcement means no harm when disturbing proper communication, can not influence minimum value in those values of the original operate as normal of system through the definite filtering algorithm of setting of μ value as μ.
Concrete, confirm 1 for thresholding in passband), can use X pThe average of the amplitude of all the frequency signals (k) is as the intermediate value M of frequency signal in the passband Av2), also can be X p(k) the frequency signal in is divided into several portions, calculates the average of amplitude of the frequency signal of each part respectively, gets minimum average then as M Av
Threshold value can be expressed as Th p=μ * M Av, then the distribution of choosing generally the spectrum value of signal can be according to proper communication time of μ is got, and generally can get 3～5.
When utilizing thresholding to carry out filtering, for the point in the passband, if amplitude surpasses thresholding Th p, or be changed to 0, or be changed to a pre-set amplitude, phase place be changed to 0 or the phase place and the amplitude that keep this point be changed to predefined value all can, be lower than thresholding Th for amplitude pGive keep.
Two, to X t(k) carry out Filtering Processing, that is, the frequency signal in the paired pulses formed filter transition band is handled.
In the enforcement, the frequency signal sets thresholding in transition band is: Th p=μ * M Av, wherein:
M AvBe the intermediate value of setting according to the attenuation characteristic segmentation or the pointwise of the transition band of filter;
μ during according to proper communication the spectrum value of signal distribute and choose.μ is a discrepancy factor, and just the amplitude of frequency will be carried out filtering above amplitude intermediate value μ those frequencies doubly.Can being chosen in the enforcement means no harm when disturbing proper communication, can not influence minimum value in those values of the original operate as normal of system through the definite filtering algorithm of setting of μ value as μ.
Perhaps, pointwise is perhaps set thresholding TH according to the attenuation characteristic segmentation that receives formed filter t=β * TH p, TH wherein pIt is the interior filter threshold of passband that the front is set.β is a decay factor, if the situation of thresholding is set in pointwise, β then is the ratio of the frequency domain amplitude in frequency domain amplitude of carrying out the corresponding reception formed filter of the frequency of filtering here and the passband that receives formed filter; If set the situation of thresholding according to the attenuation characteristic segmentation that receives formed filter, β then is the ratio of the frequency domain amplitude in maximum frequency domain amplitude of carrying out the reception formed filter that frequency is corresponding in the section of filtering here and the passband that receives formed filter.
For X p(k) but filter processing method all application by analogy in X t(k).Because the point in the transition band is the decay that will receive the transition band of pulse-shaping filter, therefore can also be according to the attenuation characteristic segmentation of the transition band of pulse-shaping filter or intermediate value M that the frequency signal is set in pointwise AvConfirm corresponding thresholding.
Three, to X s(k) carry out Filtering Processing, that is, the frequency signal in the paired pulses formed filter stopband is handled.
During processing, can directly be changed to 0 or be changed to a value and all can to the amplitude of these frequency signals near 0.
After the filtering, just can execution in step 204, the X after the Filtering Processing (k) is done the IFFT conversion, obtain through baseband signal x (m) after the anti-interference process, suppress to handle thereby accomplish the base band arrowband.
Based on same inventive concept, the present invention also provides a kind of restraining device of baseband signal narrow band interference, describes below in conjunction with the embodiment of accompanying drawing to this device.
Fig. 4 is the restraining device structural representation of baseband signal narrow band interference, and is as shown in the figure, can comprise in the restraining device:
Acquisition module 401 is used to obtain the baseband signal of reception signal after passing through the pulse-shaping filter;
Conversion module 402 is used for baseband signal is obtained to receive the signal frequency-domain signal after the FFT conversion;
Filtration module 403 is used for according to the pulse-shaping filter response frequency signal in the pulse-shaping filter passband of frequency-region signal, frequency signal and the frequency signal in the stopband in the transition band being carried out filtering respectively;
Inverse transform module 404 is used for filtered frequency-region signal is obtained to receive the baseband signal of signal after the IFFT conversion.
In the enforcement, in the time will receiving the signal frequency-domain signal according to the pulse-shaping filter response and carry out segmentation, filtration module can also be further used for confirming the impulse Response Function of pulse-shaping filter according to receiving the signals sampling cycle; Confirm the transfer function of pulse-shaping filter impulse Response Function; The Frequency Response of confirming according to said transfer function confirms to receive frequency signal, the frequency signal in the transition band and the frequency signal in the stopband in the pulse-shaping filter passband in the signal frequency-domain signal, specifically can confirm the scope of segmentation through frequency signal in the transfer function and sampling period.
In the enforcement, the pulse-shaping filter can be selected root raised cosine filter commonly used for use;
Under this scheme, filtration module can also be further used for
The frequency signal that satisfies
Figure GSB00000918833800101
is confirmed as the frequency signal in the passband;
The frequency signal that satisfies
Figure GSB00000918833800102
is confirmed as the frequency signal in the transition band;
The frequency signal that satisfies
Figure GSB00000918833800103
is confirmed as the frequency signal in the stopband;
Wherein: f is a frequency, and α is a rolloff-factor, T sFor receiving the signals sampling cycle, B is for receiving the bandwidth of signal.
In the enforcement, filtration module carries out filtering after can also being further used in passband, setting thresholding, sets said thresholding and is:
Th p=μ * M Av, wherein:
M AvBe the amplitude equalizing value of all the frequency signals in the passband, or, the frequency signal in the passband is divided into several portions, calculate the average of amplitude of the frequency signal of each part respectively, get minimum average then as M Av
μ during according to proper communication the spectrum value of signal distribute and choose.
After setting thresholding in a manner described, filtration module can be further used for amplitude is surpassed thresholding Th pThe amplitude of frequency signal be changed to 0, or be changed to predefined amplitude; The reservation amplitude is lower than thresholding Th pThe amplitude of frequency signal.
In the enforcement, filtration module carries out filtering after can also being further used in transition band, setting thresholding, sets thresholding and is:
Th p=μ * M Av, wherein:
M AvBe the intermediate value of setting according to the attenuation characteristic segmentation or the pointwise of the transition band of filter;
μ during according to proper communication the spectrum value of signal distribute and choose.
After setting thresholding, can amplitude be surpassed thresholding Th pThe amplitude of frequency signal be changed to 0, or be changed to predefined amplitude; The reservation amplitude is lower than thresholding Th pThe amplitude of frequency signal.
In the enforcement, filtration module can also be further used for the amplitude of the frequency signal in the stopband is changed to 0, perhaps is changed to the value near 0.
Owing to be based on same inventive concept with the inhibition method of baseband signal narrow band interference, therefore, the principle and the used technological means of dealing with problems described in can reference method in the implementation process of device.
Can find out from the foregoing description; The present invention is when being applied to the Suppression of narrow band interference of base band; Characteristics according to the received pulse formed filter; Divide into passband, transition band and stopband to the frequency band that receives signal; And adopt different threshold to suppress narrow band interference with different treating methods to the frequency signal in these 3 different frequency bands, thus the intensity that has overcome frequency signal, the frequency signal in the transition band and the frequency signal in the stopband do not considered in the prior art in the pulse-shaping filter passband is the deficiency that very big difference is arranged, thus improved the Suppression of narrow band interference ability of communication system.
Further, confirm the signal intermediate value according to the attenuation characteristic segmentation or the pointwise of the transition band that receives formed filter, and then the filter threshold of definite transition band, thereby better filter effect can in transition band, be obtained.
Further, the amplitude of the frequency signal in the stopband is directly put 0 or be made as one very near 0 value, thereby can in stopband, obtain better filter effect.
The present invention has taken into full account the spectral characteristic of signal through the received pulse formed filter in implementing; Frequency range to signal adopts different threshold to suppress narrow band interference with different treating methods; Compare with the Suppression of narrow band interference algorithm that adopts same thresholding and same treating method, can improve the Suppression of narrow band interference ability of communication system after the present invention implements.
Simultaneously,, therefore can use DSP (Data Signal Processor, data signal processor) to realize very easily, make and realize that cost is very low because the embodiment of the invention is the inhibition of base band to be disturbed handle.Particularly, can realize Suppression of narrow band interference through upgrading DSP, need not carry out the modification of hardware in base band for the GSM of not considering in the past Anti-interference Design.
Those skilled in the art should understand that embodiments of the invention can be provided as method, system or computer program.Therefore, the present invention can adopt the form of the embodiment of complete hardware embodiment, complete software implementation example or combination software and hardware aspect.And the present invention can be employed in the form that one or more computer-usable storage medium (including but not limited to magnetic disc store, CD-ROM, optical memory etc.) that wherein include computer usable program code go up the computer program of implementing.
The present invention is that reference is described according to the flow chart and/or the block diagram of method, equipment (system) and the computer program of the embodiment of the invention.Should understand can be by the flow process in each flow process in computer program instructions realization flow figure and/or the block diagram and/or square frame and flow chart and/or the block diagram and/or the combination of square frame.Can provide these computer program instructions to the processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce a machine, make the instruction of carrying out through the processor of computer or other programmable data processing device produce to be used for the device of the function that is implemented in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame appointments.
These computer program instructions also can be stored in ability vectoring computer or the computer-readable memory of other programmable data processing device with ad hoc fashion work; Make the instruction that is stored in this computer-readable memory produce the manufacture that comprises command device, this command device is implemented in the function of appointment in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame.
These computer program instructions also can be loaded on computer or other programmable data processing device; Make on computer or other programmable devices and to carry out the sequence of operations step producing computer implemented processing, thereby the instruction of on computer or other programmable devices, carrying out is provided for being implemented in the step of the function of appointment in flow process of flow chart or a plurality of flow process and/or square frame of block diagram or a plurality of square frame.
Although described the preferred embodiments of the present invention, in a single day those skilled in the art get the basic inventive concept could of cicada, then can make other change and modification to these embodiment.So accompanying claims is intended to be interpreted as all changes and the modification that comprises preferred embodiment and fall into the scope of the invention.

Claims (10)

1. the inhibition method of a baseband signal narrow band interference is characterized in that, comprises the steps:
Obtain and receive the baseband signal of signal after passing through the pulse-shaping filter;
Baseband signal is obtained the frequency-region signal of received signal after FFT;
Confirm the impulse Response Function of pulse-shaping filter according to the reception signals sampling cycle;
Confirm the transfer function of the impulse Response Function of pulse-shaping filter;
It is frequency signal, the frequency signal in the transition band and the frequency signal in the stopband in the pulse-shaping filter passband that the Frequency Response of confirming according to said transfer function confirms to receive the signal frequency-domain signal, and the frequency signal in the said pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band are carried out filtering respectively;
Filtered frequency-region signal is obtained to receive the baseband signal of signal behind invert fast fourier transformation.
2. the method for claim 1 is characterized in that, said pulse-shaping filter is a root raised cosine filter;
Frequency signal in the pulse-shaping filter passband in said definite frequency-region signal, the frequency signal in the transition band and the frequency signal in the stopband are specially:
The frequency signal that satisfies
Figure FSB00000918833700011
is the frequency signal in the passband;
The frequency signal that satisfies
Figure FSB00000918833700012
is the frequency signal in the transition band;
The frequency signal that satisfies
Figure FSB00000918833700013
is the frequency signal in the stopband;
Wherein: f is a frequency, and α is a rolloff-factor, T sFor receiving the signals sampling cycle, B is for receiving the bandwidth of signal.
3. like claim 1 or 2 arbitrary described methods, it is characterized in that, said frequency signal in the passband carried out filtering, be specially:
The setting filter threshold is: Th p=μ * M Av, wherein: M AvBe the amplitude equalizing value of all the frequency signals in the passband, or, the frequency signal in the passband is divided into several portions, calculate the average of amplitude of the frequency signal of each part respectively, get minimum average then as M AvThe μ discrepancy factor that the spectrum value of signal distributes and chooses for according to proper communication the time;
Amplitude is surpassed thresholding Th pThe amplitude of frequency signal be changed to 0, or be changed to predefined amplitude; The reservation amplitude is lower than thresholding Th pThe amplitude of frequency signal.
4. like claim 1 or 2 arbitrary described methods, it is characterized in that, said frequency signal in the transition band carried out filtering, be specially:
The setting thresholding is: Th p=μ * M Av, or, setting thresholding TH according to the attenuation characteristic segmentation that receives formed filter t=β * TH p, wherein: M AvBe the intermediate value of setting according to the attenuation characteristic segmentation or the pointwise of the transition band of filter; The μ discrepancy factor that the spectrum value of signal distributes and chooses for according to proper communication the time; TH pBe the filter threshold in the passband, β is the decay factor of confirming according to the ratio of the interior frequency domain amplitude of the passband of the frequency domain amplitude of the corresponding reception formed filter of the frequency signal that carries out filtering and reception formed filter;
The amplitude that amplitude is surpassed the frequency signal of thresholding is changed to 0, or is changed to predefined amplitude; The reservation amplitude is lower than the amplitude of the frequency signal of thresholding.
5. like claim 1 or 2 arbitrary described methods, it is characterized in that, said frequency signal in the stopband carried out filtering, be specially:
The amplitude of the frequency signal in the stopband is changed to 0, perhaps is changed to value near 0.
6. the restraining device of a baseband signal narrow band interference is characterized in that, comprising:
Acquisition module is used to obtain the baseband signal of reception signal after passing through the pulse-shaping filter;
Conversion module is used for baseband signal is obtained to receive the signal frequency-domain signal after FFT;
Filtration module is used for confirming the impulse Response Function of pulse-shaping filter according to receiving the signals sampling cycle; Confirm the transfer function of pulse-shaping filter impulse Response Function; The Frequency Response of confirming according to said transfer function is confirmed frequency signal, the frequency signal in the transition band and the frequency signal in the stopband in the pulse-shaping filter passband in the frequency-region signal, and the frequency signal in the said pulse-shaping filter passband, frequency signal and the frequency signal in the stopband in the transition band are carried out filtering respectively;
Inverse transform module is used for filtered frequency-region signal is obtained to receive the baseband signal of signal behind invert fast fourier transformation.
7. device as claimed in claim 6 is characterized in that, said pulse-shaping filter is a root raised cosine filter;
Said filtration module be further used for
The frequency signal that satisfies
Figure FSB00000918833700031
is confirmed as the frequency signal in the passband;
The frequency signal that satisfies
Figure FSB00000918833700032
is confirmed as the frequency signal in the transition band;
The frequency signal that satisfies
Figure FSB00000918833700033
is confirmed as the frequency signal in the stopband;
Wherein: f is a frequency, and α is a rolloff-factor, T sFor receiving the signals sampling cycle, B is for receiving the bandwidth of signal.
8. like claim 6 or 7 arbitrary described devices, it is characterized in that said filtration module carries out filtering after being further used in passband, setting thresholding, set said thresholding and be: Th p=μ * M Av, wherein:
M AvBe the amplitude equalizing value of all the frequency signals in the passband, or, the frequency signal in the passband is divided into several portions, calculate the average of amplitude of the frequency signal of each part respectively, get minimum average then as M AvThe μ discrepancy factor that the spectrum value of signal distributes and chooses for according to proper communication the time;
After setting said thresholding, amplitude is surpassed thresholding Th pThe amplitude of frequency signal be changed to 0, or be changed to predefined amplitude; The reservation amplitude is lower than thresholding Th pThe amplitude of frequency signal.
9. like claim 6 or 7 arbitrary described devices, it is characterized in that said filtration module carries out filtering after being further used in transition band, setting thresholding, set thresholding and be: Th p=μ * M Av, or, setting thresholding TH according to the attenuation characteristic segmentation that receives formed filter t=β * TH p, wherein: M AvBe the intermediate value of setting according to the attenuation characteristic segmentation or the pointwise of the transition band of filter; The μ discrepancy factor that the spectrum value of signal distributes and chooses for according to proper communication the time; TH pBe the filter threshold in the passband, β is the decay factor of confirming according to the ratio of the interior frequency domain amplitude of the passband of the frequency domain amplitude of the corresponding reception formed filter of the frequency signal that carries out filtering and reception formed filter;
After setting said thresholding, the amplitude that amplitude is surpassed the frequency signal of thresholding is changed to 0, or is changed to predefined amplitude; The reservation amplitude is lower than the amplitude of the frequency signal of thresholding.
10. like claim 6 or 7 arbitrary described devices, it is characterized in that said filtration module is further used for the amplitude of the frequency signal in the stopband is changed to 0, perhaps is changed to the value near 0.
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