CN107171693B - Broadband interference suppressing method based on Waveform Reconstructing - Google Patents
Broadband interference suppressing method based on Waveform Reconstructing Download PDFInfo
- Publication number
- CN107171693B CN107171693B CN201710277014.1A CN201710277014A CN107171693B CN 107171693 B CN107171693 B CN 107171693B CN 201710277014 A CN201710277014 A CN 201710277014A CN 107171693 B CN107171693 B CN 107171693B
- Authority
- CN
- China
- Prior art keywords
- signal
- interference
- interference signal
- frequency
- symbol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
Abstract
The invention discloses a kind of broadband interference suppressing method based on Waveform Reconstructing mainly solves the problems, such as insufficient to oppressive broadband interference signal anti-interference ability in existing spread spectrum communication system.Its technical solution is: the AF panel module based on Waveform Reconstructing being added before the matched filtering of spread spectrum communication system receiving end, interference signal symbol rate estimates, Timing Synchronization and interference signal is first passed sequentially through to demodulate to obtain interference sequence, interference signal is reconstructed further according to obtained interference sequence, the inhibition realized to interference signal is then offset by delay；Matched filtering, synchronization acquistion, the despreading and demodulation decoding that residual signal after finally interference signal is inhibited successively passes through original system obtain useful information.The present invention restrained effectively high-power broadband interference digital signal, and structure is simple, and implementation complexity is low, can be used for improving the anti-interference ability of communication system.
Description
Technical field
It is logical for enhancing the invention belongs to field of communication technology, the in particular to suppressing method of wideband digital interference signal
The anti-interference ability of letter system improves the validity of signal transmission.
Background technique
Modern Communication System will receive various interference effects in real space environment, so as to the treatability for receiving signal
Can be by heavy losses, therefore, the anti-interference ability for improving communication system has great significance for the guarantee of communication quality.
Current main Anti-jam Communication Technology has: short burst communication technology, diversity receiving technology and spread spectrum technic etc., wherein expanding
The frequency communication technology becomes the current main communication technology because it has the advantages that big capacity, strong antijamming capability, intercepting and capturing rate are low
One of, it is widely used in the Modern Communication System such as satellite communication.As shown in Figure 1.Original spread spectrum communication system relies only on certainly
The anti-interference ability of body inhibits to interfere, without additional interference suppression measure.But it is when the power of interference signal is much larger than
When the jamming margin of system, the simple spreading gain by system itself is unworkable to inhibit to interfere, so to there is other hands
Section come achieve the purpose that effectively inhibit interference.
Most researchs to effective disturbance restraining method are interfered both for narrowband type at present, and general method is
Add a trapper unit before the processing of receiving terminal useful signal, power weakening is carried out to high reject signal.With signal
Transmission rate is getting faster, and signal bandwidth is more and more wider, and influence of the broadband interference to communication system becomes increasing, therefore
No matter being carried out on the basis of spread spectrum communication system to the Interference Suppression Study of high-power broadband interference signal in terms of theoretical research
Or it can all have great significance in terms of practical application.And since trapper can generate useful signal when broadband interference inhibits
Larger impact, so carrying out broadband interference using the thinking of trap inhibits just no longer suitable.Currently broadband interference is inhibited
It studies opposite narrowband the Study of Interference to be lacked more, is insufficient for the demand that current communication networks inhibit broadband interference.
In existing disturbance restraining method, mainly have using the spatial processing method of aerial array, frequency domain null method and for line
Some suppressing methods such as property frequency modulation broadband interference, but these methods have the limitation of itself.It is carried out using aerial array
The system of AF panel, mainly by interference signal and useful signal come at attitude information as difference
Reason, but this technology is extremely limited for wideband interferer signal inhibitory effect, to inhibit broadband interference well, it is necessary to increase
Add array antenna number, which adds the complexities of realization；Based on the method that frequency domain eliminates interference, it is only suitable for narrowband interference suppression
System can not be directly by interference signal from frequency domain since wideband interferer signal and useful signal are on frequency domain together with elementary mixing
It eliminates；Linear frequency modulation is a kind of common modulation system, and for this kind of signal, the most commonly used technology of current application is discrete
Chirp-Fourier transform method, it is the popularization of Discrete Fourier Transform, can effectively inhibit chirp waveform signal,
But it is unsatisfactory for the inhibitory effect of phase modulated signal.
Summary of the invention
Present invention aims at the deficiencies for making up above-mentioned technology, on the basis of Direct Sequence Spread Spectrum Communication, from time domain weight
The angle of structure, which is set out, proposes a kind of broadband interference suppressing method based on Waveform Reconstructing, to realize to phase-modulation interference signal
Effectively inhibit, improves the interference free performance of spread spectrum communication system.
Technical thought of the invention is: doing for insertion one before the processing of original direct sequence spread spectrum communication system receiving end
Suppression module is disturbed, by the AF panel model of foundation " interference signal demodulation-interference signal reconstruct-Interference Cancellation ", according to
Receiving end mixed signal reconstructs interference signal to come, and obtains approximate interference signal, is then being mixed by way of counteracting
It is curbed in signal, implementation includes the following:
(1) interference signal symbol rate estimates:
(1a) is according to the carrier frequency f of interference signald, generating a corresponding frequency is-fdLocal signal, use frequency
For-fdLocal signal multiplied by the base band mixed signal of receiving end, obtain interference and move to mixed signal after zero-frequency；
(1b) carries out time-frequency domain correlating transforms to the mixed signal that (1a) is obtained using Haar small echo, obtains interference signal
Chip rate Rb；
(2) interference signal symbol Timing Synchronization:
(2a) chip rate R according to obtained in step (1)b, in conjunction with sample frequency fs, with sample frequency fsDivide exactly symbol
Rate Rb, acquire the number of sampling points in a code-element period；
(2b) directly carries out wavelet transformation to the mixed signal that (1a) is obtained, and searches from the signal that transformation obtains the
One catastrophe point position obtains the initial position of interference signal symbol in conjunction with the number of sampling points in single code-element period, real
Existing Timing Synchronization；
(3) successively right using number of sampling points in single code-element period as interval since the initial position of interference signal
The mixed signal that (1a) is obtained is demodulated, and original 0,1 interference sequence are obtained；
(4) interference signal waveform is reconstructed:
(4a) is according to jamming signal bandwidth B and chip rate Rb, acquire the rolloff-factor α of forming filter；
(4b) carries out corresponding modulation to obtained 0,1 interference sequence of step (3) demodulation, more than the liter with rolloff-factor for α
Filtering is formed to the signal after modulation in string filter, is f multiplied by frequencydCarrier wave, the interference signal reconstructed；
(5) by delay offset, in former base with the interference signal reconstructed is subtracted in mixed signal, obtain AF panel it
Residual signal afterwards.
Compared with the prior art, the present invention has the following advantages:
First, the present invention compensates for currently to the deficiency of broadband interference suppressing method research, realizes to high-power broadband phase
Effective inhibition of position modulated interferer signal, from time domain reconstruction, compensating for interference signal and useful signal on frequency domain can not divide
From the drawbacks of.
Second, AF panel model structure proposed by the present invention is simple, is easy to implement, and reduces existing interference mitigation technology
Implementation complexity, improve the anti-interference ability of spread spectrum communication system.
Detailed description of the invention
Fig. 1 is the structural block diagram of existing spread spectrum communication system；
Fig. 2 is implementation flow chart of the invention；
Fig. 3 is provided with spread spectrum communication system receiving end structural block diagram of the invention；
Fig. 4 is that the frame error rate decoded respectively to useful signal with Fig. 3 system and Fig. 1 system compares figure.
Specific embodiment
The embodiment of the present invention and effect are further described below in conjunction with attached drawing:
Referring to Fig.1, existing spread spectrum communication system, transmitting terminal include coding demodulator, spread spectrum module, shaping filter
Device, intermediate frequency transmitter and D/A converter；Its receiving end include down-conversion receiver, A/D converter, matched filter and
Useful signal processing module；Transmitting terminal information source successively by coding, modulation, spread spectrum and shaping filter, then by D/A convert and on
Frequency-conversion processing sends signal, and white Gaussian noise and interference signal are added in the channel；Receiving end passes through down-converted
Converting with A/D becomes base-band digital mixed signal for signal, then passes through matched filtering, synchronization acquistion, despreading and demodulation decoding
Obtain useful information.When interfering signal power is more than the jamming margin of the system, the anti-interference ability of the system can seriously not
Foot, needs effective disturbance restraining method to carry out corresponding AF panel.
AF panel is added before the matched filtering of existing spread spectrum communication system receiving end in the present invention, i.e., in down coversion
AF panel is carried out later, that is, carries out relevant operation in base band, by inhibiting to interference signal, weakening or eliminating
Fall interference signal, the signal after the interference that is inhibited.
Referring to Fig. 2, steps are as follows to the realization that interference is inhibited by the present invention:
Step 1, the chip rate of estimated disturbance signal.
(1a) is according to the carrier frequency f of interference signald, generating a corresponding frequency is-fdLocal signal, use frequency
For-fdLocal signal multiplied by the base band mixed signal of receiving end, obtain interference and move to mixed signal r (n) after zero-frequency；
(1b) carries out time-frequency domain correlating transforms to the mixed signal that (1a) is obtained using Haar wavelet transformation, and estimation is done
Disturb the chip rate R of signalb=4MHz:
(1b1) is defined by wavelet transformationUsing Haar small echo to mixing
Signal r (n) is converted, and wavelet transform result is obtained, wherein τ is shift factor for a scale factor,For Haar small echo
Function is r (t) function to be transformed；
(1b2) successively carries out modulus to transformation results, modulus value is squared and FFT transform；
(1b3) finds the maximum position of modulus value to FFT transform result modulus value, and with the position multiplied by frequency resolution
Obtain chip rate Rb=4MHz.
Step 2, synchronization is timed to interference signal symbol.
(2a) chip rate R according to obtained in step 1b, in conjunction with sample frequency fs=80MHz, with sample frequency divided by code
First rate acquires the number of sampling points N=20 in a code-element period；
(2b) is converting obtained signal to interfering the mixed signal r (n) after moving to zero-frequency directly to carry out wavelet transformation
In search first catastrophe point position, in conjunction with the number of sampling points in single code-element period, divide exactly list with catastrophe point position
Number of sampling points in a code-element period is thus done using remainder as effective initial position of interference signal symbol
The initial position of signal element is disturbed, realizes Timing Synchronization.
Step 3, the demodulation of interference signal.
Since the initial position of interference signal, using number of sampling points in single code-element period as interval, successively to interference
The mixed signal r (n) moved to after zero-frequency is demodulated, if r (n) > 0, interference signal is demodulated into 1, is otherwise demodulated into
0, in this way, having obtained original 0,1 interference sequence si(n)。
Step 4, interference signal is reconstructed.
The chip rate R that (4a) is obtained according to the interference signal baseband bandwidth set as B=3MHz and step 2b=4MHz,
Pass through the rolloff-factor of following equations forming filter:
(4b) demodulates obtained interference signal sequence s according to step 3i(n), modulated by BPSK, with rolloff-factor for α=
0.5 raised cosine filter it is formed filtering, is f multiplied by frequencydCarrier wave, the interference signal reconstructed.
Step 5, the residual signal after obtaining AF panel is offset by delay.
(5a) counts interference signal symbol rate estimates, interference signal demodulation and interference signal Waveform Reconstructing, and these are grasped
Time delay caused by work, is denoted as τd；
(5b) carries out the time to former base band mixed signal as τdTime delay, and it is subjected to phase with the interference signal that reconstructs
Reducing realizes counteracting, the residue for the interference that is inhibited with the interference signal reconstructed is subtracted in mixed signal in former base
Signal.
The present invention is added to the receiving end of spread spectrum communication system, forms new spread spectrum communication system, as shown in Figure 3.
Referring to Fig. 3, this step is implemented as follows:
Former spread spectrum communication system receiving end is by obtaining base band mixed signal, then benefit after down coversion and A/D conversion process
With disturbance restraining method of the invention, of former spread spectrum communication system receiving end is added in the form of an AF panel module
Before filter, by carrying out AF panel, the residual signal for the interference that is inhibited to base band mixed signal；
Residual signal after AF panel of the present invention is continued on original spread spectrum communication system receiving end subsequent
Processing first carries out matched filtering to residual signal, then synchronizes capture to the signal after matched filtering, then to capture
Successful signal carries out corresponding despreading, finally completes demodulation coding to the signal after despreading, obtains useful information.
Effect of the invention is described further below by emulation experiment:
1. simulated conditions
Using MATLAB 8.6.0 simulation software, AF panel performance is emulated, transmission channel is additive white gaussian
Noisy communication channel, interference signal are modulated by BPSK, the raised cosine forming filter for being 0.5 by rolloff-factor to signal shaping,
Interference signal residual carrier frequency fd5MHz is taken, baseband bandwidth takes 3MHz；Sample frequency fsIt is set as 80MHz, signal-to-noise ratio is set as-
26dB, signal interference ratio setting are respectively -42dB~-36dB, and the scene application of high-power broadband interference is realized with this.
2. emulation content
Emulation 1, is added to former spread spectrum communication system for the interference signal of arrangement above, original system is no longer able to be correctly obtained
Useful information.
Emulation 2 carries out effect emulation to the AF panel performance that spread spectrum communication system of the invention is added, obtains useful letter
The frame error rate curve of number correct decoding, as a result as shown in Figure 4.
It can be seen from the simulation result of Fig. 4 under the premise of signal-to-noise ratio is -26dB, when signal interference ratio is less than -38dB, have
The frame error rate correctly demodulated with signal is less than 10-2, meet performance requirement, moreover, signal interference ratio is smaller, what useful signal correctly demodulated
Frame error rate is smaller, this is because signal interference ratio is smaller, interfering signal power is relatively bigger, illustrates that the present invention interferes high-power broadband
Signal has good inhibitory effect.
Claims (5)
1. the broadband interference suppressing method based on Waveform Reconstructing, it is characterised in that:
(1) interference signal symbol rate estimates:
(1a) is according to the carrier frequency f of interference signald, generating a corresponding frequency is-fdLocal signal, with frequency be-fd
Local signal multiplied by the base band mixed signal of receiving end, obtain interference and move to mixed signal after zero-frequency；
(1b) carries out time-frequency domain correlating transforms to the mixed signal that (1a) is obtained using Haar small echo, obtains the symbol of interference signal
Rate Rb；
(2) interference signal symbol Timing Synchronization:
(2a) chip rate R according to obtained in step (1)b, in conjunction with sample frequency fs, with sample frequency fsDivide exactly chip rate
Rb, acquire the number of sampling points in a code-element period；
(2b) directly carries out wavelet transformation to the mixed signal that (1a) is obtained, and searches first from the signal that transformation obtains
Catastrophe point position obtains the initial position of interference signal symbol in conjunction with the number of sampling points in single code-element period, and it is fixed to realize
When it is synchronous；
(3) since the initial position of interference signal, using number of sampling points in single code-element period as interval, successively (1a) is obtained
To mixed signal demodulated, obtain original 0,1 interference sequence；
(4) interference signal waveform is reconstructed:
(4a) is according to jamming signal bandwidth B and chip rate Rb, acquire the rolloff-factor α of forming filter；
0,1 interference sequence that (4b) obtains step (3) demodulation carries out corresponding modulation, is filtered with rolloff-factor for the raised cosine of α
Filtering is formed to the signal after modulation in wave device, is f multiplied by frequencydCarrier wave, the interference signal reconstructed；
(5) it is offset by delay, in former base with the interference signal reconstructed is subtracted in mixed signal, after obtaining AF panel
Residual signal.
2. according to the method described in claim 1, the mixed signal that (1a) is obtained using Haar small echo in its step (1b) into
The processing of row time-frequency domain conversation, its step are as follows:
(1b1) is defined by wavelet transformationUsing Haar small echo to mixed signal r
(t) it is converted, obtains wavelet transform result, wherein τ is shift factor for a scale factor,For Haar wavelet function；
(1b2) successively carries out modulus to transformation results, modulus value is squared and FFT transform；
(1b3) finds the maximum position of modulus value to FFT transform result modulus value, and is obtained with the position multiplied by frequency resolution
Chip rate.
3. according to the method described in claim 1, in its step (2b) interference signal symbol initial position determine, be with mutation
The number of sampling points in single code-element period is divided exactly in point position, using remainder as effective initial position of interference signal symbol.
4. according to the method described in claim 1, the rolloff-factor α of the forming filter in its step (4a), passes through following public affairs
Formula solves:
Wherein, B is jamming signal bandwidth, RbFor interference signal symbol rate.
5. according to the method described in claim 1, the step of delay is offset in its step (5) is as follows:
(5a) statistics interference signal symbol rate estimates, interference signal demodulation and interference signal Waveform Reconstructing these operations are made
At time delay, be denoted as τd；
(5b) carries out the time to former base band mixed signal as τdTime delay, and it is carried out to subtract each other behaviour with the interference signal reconstructed
Make, realizes and offset.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710277014.1A CN107171693B (en) | 2017-04-25 | 2017-04-25 | Broadband interference suppressing method based on Waveform Reconstructing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710277014.1A CN107171693B (en) | 2017-04-25 | 2017-04-25 | Broadband interference suppressing method based on Waveform Reconstructing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107171693A CN107171693A (en) | 2017-09-15 |
| CN107171693B true CN107171693B (en) | 2019-03-26 |
Family
ID=59813360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710277014.1A Active CN107171693B (en) | 2017-04-25 | 2017-04-25 | Broadband interference suppressing method based on Waveform Reconstructing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107171693B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109781153B (en) | 2018-12-17 | 2020-08-11 | 北京理工大学 | Physical parameter estimation method and device and electronic equipment |
| CN109802719B (en) * | 2019-01-03 | 2020-07-17 | 长沙天仪空间科技研究院有限公司 | Satellite communication system based on narrow-band interference suppression |
| CN111510193B (en) * | 2020-03-27 | 2022-03-25 | 中国人民解放军海军工程大学 | Non-cooperative interference suppression device for satellite ground station and control method thereof |
| CN112187338B (en) * | 2020-09-17 | 2022-06-07 | 中国电子科技集团公司第三十八研究所 | Two-stage processing interference cancellation system and method for asynchronous CDMA system |
| CN112737616B (en) * | 2020-12-29 | 2022-06-21 | 成都国星通信有限公司 | Beidou communication antenna pulse interference suppression method and suppression circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1346189A (en) * | 2000-09-30 | 2002-04-24 | 华为技术有限公司 | Doppler small wave base based self-adaptive coherent interference suppression method |
| EP1926217A3 (en) * | 2006-11-24 | 2011-04-13 | Samsung Electronics Co., Ltd. | Intercell Interference cancellation in an OFDMA Broadband Wireless Access communication system |
| CN102025392A (en) * | 2010-12-06 | 2011-04-20 | 意法·爱立信半导体（北京）有限公司 | Interference elimination method and device |
| CN102087353A (en) * | 2009-12-08 | 2011-06-08 | 北京邮电大学 | Method and equipment for suppressing interference |
| CN105659197A (en) * | 2014-01-26 | 2016-06-08 | 华为终端有限公司 | Interference suppression method and apparatus for touch screen and terminal device |
-
2017
- 2017-04-25 CN CN201710277014.1A patent/CN107171693B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1346189A (en) * | 2000-09-30 | 2002-04-24 | 华为技术有限公司 | Doppler small wave base based self-adaptive coherent interference suppression method |
| EP1926217A3 (en) * | 2006-11-24 | 2011-04-13 | Samsung Electronics Co., Ltd. | Intercell Interference cancellation in an OFDMA Broadband Wireless Access communication system |
| CN102087353A (en) * | 2009-12-08 | 2011-06-08 | 北京邮电大学 | Method and equipment for suppressing interference |
| CN102025392A (en) * | 2010-12-06 | 2011-04-20 | 意法·爱立信半导体（北京）有限公司 | Interference elimination method and device |
| CN105659197A (en) * | 2014-01-26 | 2016-06-08 | 华为终端有限公司 | Interference suppression method and apparatus for touch screen and terminal device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107171693A (en) | 2017-09-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107171693B (en) | Broadband interference suppressing method based on Waveform Reconstructing | |
| CN101286752B (en) | Implementing method of ultra-wideband orthogonal forming pulse | |
| CN103487815B (en) | A kind of satellite navigation signal enhancement method based on orthogonal domain interference optimization overlapping multiplexing | |
| CN107612865B (en) | Signal noise reduction method applied to low-voltage power line carrier communication | |
| CN105790788B (en) | A kind of pseudo-code of direct expansion msk signal-Doppler's joint acquisition method | |
| CN102546499B (en) | Fractional-order channelized receiving method of real linear frequency modulation (LFM) signal | |
| CN104468436A (en) | Communication signal wavelet domain blind source separation anti-interference method and device | |
| CN109450489A (en) | A kind of pilot frequency sequence interference cancellation method of spread-spectrum underwater sound communication | |
| CN110933007B (en) | Device and method for eliminating interference aiming at OFDM broadband signal | |
| CN111210665A (en) | Satellite-borne AIS time slot collision signal separation method based on single antenna | |
| CN114915316B (en) | Band-limited direct sequence spread spectrum signal digital code tracking method based on frequency domain processing | |
| CN108880604A (en) | Multi -components frequency modulation disturbance restraining method and device in a kind of spread spectrum communication system | |
| CN113783820B (en) | QPSK-CPM spread spectrum multi-user detection method based on satellite-borne VDE | |
| CN110113273B (en) | Time-frequency overlapping signal blind separation method based on frequency spectrum symmetry | |
| US10581481B1 (en) | Communication device, spread-spectrum receiver, and related method using normalized matched filter for improving signal-to-noise ratio in harsh environments | |
| CN104601514B (en) | The disturbance restraining method of joint subspace projection and CLEAN | |
| CN110286392A (en) | It is a kind of that implementation method is interfered based on the down-sampled anti-narrowband of frequency domain | |
| CN113541706B (en) | Narrow-band interference suppression method based on transform domain processing | |
| CN112600784B (en) | Large frequency offset bit synchronization method based on quadratic differential correlation | |
| CN114553656A (en) | Weak signal capturing method based on unequal-length double-block zero-filling algorithm | |
| Yu et al. | A waveform with low intercept probability for OFDM SAR | |
| Qin et al. | Effects of interference mitigation methods on scintillation detection | |
| Zhang et al. | Narrowband interference suppression in DSSS system based on frequency shift wavelet packet transform | |
| CN113630152B (en) | Guiding type digital anti-interception anti-interference device and method | |
| CN112134581B (en) | Method for acquiring local dirty correlation template of UWB receiver |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |