CN108736921A - A kind of power line carrier communication lead detecting method for resisting random impulsive noise - Google Patents
A kind of power line carrier communication lead detecting method for resisting random impulsive noise Download PDFInfo
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- CN108736921A CN108736921A CN201710260656.0A CN201710260656A CN108736921A CN 108736921 A CN108736921 A CN 108736921A CN 201710260656 A CN201710260656 A CN 201710260656A CN 108736921 A CN108736921 A CN 108736921A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B15/00—Suppression or limitation of noise or interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/46—Monitoring; Testing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
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- Computer Networks & Wireless Communication (AREA)
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- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
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Abstract
The present invention provides a kind of power line carrier communication lead detecting method for resisting random impulsive noise, this method is by caching local leader fragment, and pulse noise reduction process is carried out to signal, then the leader fragment of local cache and input signal are subjected to cross-correlation calculation, and autocorrelation calculation is carried out to input signal, cross-correlation and autocorrelation calculation result are substituted into normalized decision function；It is compared with the result of calculation of decision function finally by the threshold value of setting, obtains the testing result of leading cyclic sequence unit.Compared to traditional lead detecting method, lead detecting method provided by the invention has better robustness to random impulsive noise, and this method is not in interference peak in frame end, the illusion that can effectively avoid another frame signal from arriving.
Description
Technical field
The present invention relates to digital information transmission field, more particularly to a kind of power line carrier for resisting random impulsive noise is logical
Believe lead detecting method.
Background technology
With the development of network technology, power line carrier, PLC is because having the advantages that wide, the low laying cost of distribution, in information man
It is greatly paid close attention in the applications such as electricity, building intelligent.
The transmission environment of power line carrier, PLC is very complicated, and in communication process, random impulsive noise is due to its own
High-power feature, it is very big to power carrier communication system interference, become an important factor for hindering power line communication performance.
In power line carrier, PLC, leading is the important component of frame structure, and main function includes that frame detection, symbol are same
Step, channel estimation, offset estimation, AGC (automatic gain control automatic growth controls) etc..Therefore, it is carried in electric power
During wave communication, detection of preamble has very important effect to communication.
Traditional lead detecting method mainly has：1, sequence Autocorrelation Detection algorithm, i.e., when signal arrives, according to leading
Targeting sequencing number in symbol carries out Autocorrelation Detection, then determines frame start position by judging threshold value.This method
Determine that correlation threshold is cumbersome, it is poor to the robustness of random impulsive noise.2, delay and correlation algorithm is examined in sequence auto-correlation
Energy term is introduced on the basis of method of determining and calculating, using the ratio of continuous item energy term, i.e. normalized, then determines that threshold value is come
Determine frame start position.Compared to sequence Autocorrelation Detection algorithm, delay and correlation algorithm is without the concern for practical threshold value.But due to
Energy window subscript is ahead of associated window, therefore when energy declines rapidly, and correlation does not decline rapidly, causes in frame end
The interference peak that will appear a period of time is likely to result in the illusion that another frame arrives.
For case above, in complicated power line carrier, PLC environment, power line carrier, PLC is realized stable and reliable
Data transmission is very important, this is a urgent task for power carrier communication system design.
Invention content
It is an object of the present invention in low voltage electric power carrier communication system, to overcome random impulsive noise to leading inspection
The influence of survey, to provide a kind of power line carrier communication lead detecting method for resisting random impulsive noise.
To achieve the goals above, the present invention provide it is a kind of power line carrier, PLC receiving terminal be based on local targeting sequencing with
The lead detecting method of input signal related operation.The method specifically includes following steps：
In the single leader fragment of local cache, which requires to follow with leading in input signal step 1)
The structure of ring sequence units is consistent；
Step 2) combines the feature of leading cyclic sequence unit, by detecting the range value of input signal, determines input letter
Number by random impulsive noise interfere position, and to the position carry out amplitude limiting processing；
The leader fragment of local cache and input signal are carried out cross-correlation calculation by step 3), and to input signal into
Cross-correlation and autocorrelation calculation result are substituted into normalized decision function by row autocorrelation calculation；
Step 4) is compared by the threshold value of setting with the result of calculation of decision function, and leading cyclic sequence unit is obtained
Testing result.
As a further improvement of the above technical scheme, the step 2) specifically includes：Step 201) calculates step 1)
The probability distribution maximum amplitude of the leader fragment of middle local cache, i.e., the width of the maximum probability occurred in leader fragment
Angle value；
Step 202) reads input signal rk, and check input signal rkIn the range value each put, given threshold T1 will
Corresponding assignment probability distribution maximum amplitude of range value more than threshold value T1.
As a further improvement of the above technical scheme, the step 3) specifically includes：
Sliding window is arranged in step 301), receives input signal；
The leader fragment of input signal and local cache is carried out cross-correlation calculation by step 302), and calculation formula indicates
For：
Wherein, SkFor the leader fragment of local cache, rk+nFor input signal, N is the length of leader fragment, L
For input signal length, n is n-th point in input signal, and k is C k-th point in leader fragmentnIt is mutual for n-th point
Correlation calculation result；
Input signal is carried out autocorrelation calculation by step 303), and calculation formula is expressed as：
Wherein, PnFor n-th point of autocorrelation calculation result；
The result of calculation of step 302) and step 303) is substituted into normalized decision function, the decision function table by step 304)
It is shown as：
Wherein, MnFor n-th point of decision function result of calculation.
As a further improvement of the above technical scheme, the step 4) specifically includes：
Step 401) given threshold T2 judges the decision function result of calculation each put in input signal if it is greater than threshold value
402) T2 is thened follow the steps；
Step 402) continues to judge whether the point more than threshold value T2 is the maximum of points of decision function, if it is not, then judging
It is random impulsive noise interference to cause, gives up the corresponding decision function result of calculation of the point, if so, is determined as that detection completes one
A leading cyclic sequence unit executes step after the completion of all leading cyclic sequence units in input signal are detected
403)；
Step 403) given threshold T3 judges the decision function result of calculation of the point in input signal if it is less than the threshold value
T3 is then judged to completing the detection of all leading cyclic sequence units in input signal.
A kind of power line carrier communication lead detecting method advantage of resistance random impulsive noise of the present invention is：
Compared to traditional lead detecting method, lead detecting method provided by the invention has random impulsive noise good
Robustness, this method is not in interference peak in frame end, the illusion that can effectively avoid another frame signal from arriving.
Description of the drawings
Fig. 1 is a kind of power line carrier communication lead detecting method flow for resisting random impulsive noise provided by the invention
Figure.
Fig. 2 is the lead data format provided during the present invention is implemented.
Fig. 3 is not introduce under any noise conditions, normalized decision function simulation result.
Fig. 4 is to introduce under the conditions of random impulsive noise, is emulated using the detection of preamble that traditional delay and correlation algorithm obtains
As a result.
Fig. 5 is to introduce under the conditions of random impulsive noise, the simulation result obtained using the lead detecting method of the present invention.
Fig. 6 is to introduce under the conditions of random impulsive noise, and random pulses inhibition is carried out using the lead detecting method of the present invention
And the simulation result obtained after normalized.
Specific implementation mode
It is logical to a kind of power line carrier for resisting random impulsive noise of the present invention with reference to the accompanying drawings and examples
Letter lead detecting method is described in detail.
As shown in Figure 1, the present invention proposes a kind of power line carrier communication detection of preamble side resisting random impulsive noise
Method, the specific steps are：
In the single leader fragment of local cache, which requires to follow with leading in input signal step 1)
The structure of ring sequence units is consistent；
Step 2) combines the feature of leading cyclic sequence unit, by detecting the range value of input signal, determines input letter
Number by random impulsive noise interfere position, and to the position carry out amplitude limiting processing；
The leader fragment of local cache and input signal are carried out cross-correlation calculation by step 3), and to input signal into
Cross-correlation and autocorrelation calculation result are substituted into normalized decision function by row autocorrelation calculation；
Step 4) is compared by the threshold value of setting with the result of calculation of decision function, and leading cyclic sequence unit is obtained
Testing result.
For traditional delay and correlation algorithm decision function, it is defined as follows：
Wherein, r is input signal, and L indicates that input signal length, j indicate current demand signal position, CnIt is input signal from phase
It closes and calculates, PnFor energy term.As shown from the above formula, PnSubscript is ahead of Cn, therefore when energy declines rapidly, correlation does not have
There is rapid decline, lead to the interference peak that will appear a period of time in frame end, is likely to result in the illusion that another frame arrives,
There are multiple interference peaks in situation i.e. as shown in Figure 4.And for continuous input term signal, need to carry out serial correlation
It calculates, increases calculation amount.
And the present invention carries out pulse noise reduction process by being detected to input signal to signal.Then before caching local
Cyclic sequence segment is led, sliding window is set, input signal is calculated, not only increases computational efficiency, and can keep away
Exempt from PnSubscript is ahead of Cn, the interference peak for causing to will appear a period of time in frame end is prevented, another frame is likely to result in and arrives
The illusion come.
Therefore this method compares traditional sequence correlation detection, possesses better noiseproof feature.It is related compared to delay to calculate
Method, this method are not in interference peak when frame end, the illusion that can effectively avoid another frame signal from arriving.
Embodiment one
Based on above-mentioned power line carrier communication lead detecting method, in this example, the specific reality of the lead detecting method
Step is applied to specifically include：
Step 1) is with reference to the preamble structure of power line communication shown in Fig. 2, and preamble structure is by 10.5 SYNCP and 2.5
SYNCM is formed, wherein SYNCM=-SYNCP.SYNCP is defined as：
Cache the leader fragment S that single length is N=1024kTo local, SkIt is given birth to by (1) formula for single standard preamble
At this refers to intercept a certain segment, leader fragment and input signal r from single leading cyclic sequence SYNCPkIn
Leading cyclic sequence cellular construction is consistent, while the average value for calculating the leader fragment of local cache is 2047.
Step 2) reads input signal, and checks the range value each put in input signal, given threshold 4096, judges
Whether the signal amplitude value each put is more than the threshold value；The corresponding assignment probability distribution of range value that will be greater than the threshold value is maximum
Amplitude.
It is N=1024 that sliding window length, which is arranged, in step 3), receives input signal, and to improve computational efficiency, the present invention passes through
It after setting sliding window need not cache all data, is then calculated again, it is only necessary to which buffer storage length is the data of N, is then led to
The mode for crossing displacement calculates each point.
Step 4) is by the single leader fragment S of local cachekWith input signal rkCarry out correlation computations, calculation formula
It is expressed as：
Wherein, SkFor the leader fragment of local cache, rk+nFor input signal, N is the length of leader fragment, L
For input signal length, n is n-th point in input signal, and k is C k-th point in leader fragmentnIt is mutual for n-th point
Correlation calculation result.
Input signal is carried out energy autocorrelation calculation by step 5), and calculation formula is expressed as：
Wherein, PnFor n-th point of autocorrelation calculation result.
The result of calculation of step 4) and step 5) is substituted into following decision function by step 6) normalized：
Wherein, MnFor n-th point of decision function result of calculation.
Step 7) given threshold 0.9, judges MnWhether the threshold value is more than.If Mn> 0.9 then can be determined that input letter
Number arrive, execute next step.
Step 8) judges current MnWhether the position of corresponding points is the maximum of points of decision function, if so, illustrating single
Leading cyclic sequence unit detection is completed.In conjunction with preamble structure, according to correlation calculations it is found that normalization structure MnMaximum value position
It sets in last position of single leading cyclic sequence unit, and will appear 12 peak values.It is as shown in Figure 3 the result is that not drawing
Enter the simulation result under conditions of any noise.If current MnThe position of corresponding points be not single leading cyclic sequence unit most
Latter position, it may be considered that being then to give up the corresponding decision function result of calculation of the point caused by noise jamming.
The last set threshold value 0.1 of step 9), judges MnWhether the threshold value is less than, if so, being judged to completing input
The detection of all leading cyclic sequence units in signal.
As shown in Figure 5, Figure 6, it is the emulation utilized in the present embodiment in above-mentioned lead detecting method specific implementation process
As a result.Wherein, noise reduction process is not being carried out, the results are shown in Figure 5 for decision function, and as can be seen from the figure result fluctuates
It is larger, serious impulse noise interference can be caused to determine decision function threshold value comparison trouble.Fig. 6 is shown through extra pulse
Noise processed and the simulation result being normalized compare Fig. 5, and the decision function result that Fig. 6 is shown is smoother, is more convenient for
Determine decision function threshold value.
It should be noted last that the above examples are only used to illustrate the technical scheme of the present invention and are not limiting.Although ginseng
It is described the invention in detail according to embodiment, it will be understood by those of ordinary skill in the art that, to the technical side of the present invention
Case is modified or replaced equivalently, and without departure from the spirit and scope of technical solution of the present invention, should all be covered in the present invention
Right in.
Claims (4)
1. a kind of power line carrier communication lead detecting method for resisting random impulsive noise, which is characterized in that including：
In the single leader fragment of local cache, which requires and leading cycle sequence in input signal step 1)
The structure of column unit is consistent；
Step 2) combine leading cyclic sequence unit feature, by detect input signal range value, determine input signal by
The position of random impulsive noise interference, and amplitude limiting processing is carried out to the position；
The leader fragment of local cache and input signal are carried out cross-correlation calculation by step 3), and are carried out certainly to input signal
Cross-correlation and autocorrelation calculation result are substituted into normalized decision function by correlation computations；
Step 4) is compared by the threshold value of setting with the result of calculation of decision function, and the inspection of leading cyclic sequence unit is obtained
Survey result.
2. the power line carrier communication lead detecting method according to claim 1 for resisting random impulsive noise, feature
It is, the step 2) specifically includes：
Step 201) calculates the probability distribution maximum amplitude of the leader fragment of local cache in step 1), i.e. targeting sequencing piece
The range value of the maximum probability occurred in section；
Step 202) reads input signal rk, and check input signal rkIn the range value each put, given threshold T1 will be greater than
Corresponding assignment probability distribution maximum amplitude of range value of threshold value T1.
3. the power line carrier communication lead detecting method according to claim 1 for resisting random impulsive noise, feature
It is, the step 3) specifically includes：
Sliding window is arranged in step 301), receives input signal；
The leader fragment of input signal and local cache is carried out cross-correlation calculation by step 302), and calculation formula is expressed as：
Wherein, SkFor the leader fragment of local cache, rk+nFor input signal, N is the length of leader fragment, and L is defeated
Enter signal length, n is n-th point in input signal, and k is C k-th point in leader fragmentnFor n-th point of cross-correlation
Result of calculation；
Input signal is carried out autocorrelation calculation by step 303), and calculation formula is expressed as：
Wherein, PnFor n-th point of autocorrelation calculation result；
The result of calculation of step 302) and step 303) is substituted into normalized decision function by step 304), which indicates
For：
Wherein, MnFor n-th point of decision function result of calculation.
4. the power line carrier communication lead detecting method according to claim 1 for resisting random impulsive noise, feature
It is, the step 4) specifically includes：
Step 401) given threshold T2, judges in input signal the decision function result of calculation each put if it is greater than threshold value T2,
It thens follow the steps 402)；
Step 402) continue judge more than threshold value T2 point whether be decision function maximum of points, if it is not, then judgement be with
Machine impulse noise interference causes, and gives up the corresponding decision function result of calculation of the point, if so, before being determined as that detection completes one
Cyclic sequence unit is led, after the completion of all leading cyclic sequence units in input signal are detected, executes step 403)；
Step 403) given threshold T3, judges the decision function result of calculation of the point in input signal if it is less than threshold value T3,
Then it is judged to completing the detection of all leading cyclic sequence units in input signal.
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| CN110351210A (en) * | 2019-07-16 | 2019-10-18 | 深圳智微电子科技有限公司 | A kind of channel estimation improved method for OFDM preamble communication signal |
| CN110381005A (en) * | 2019-09-06 | 2019-10-25 | 成都博高信息技术股份有限公司 | Detection method, device, equipment and the medium of power line communication leading character relevant peaks |
| CN112187317A (en) * | 2020-10-08 | 2021-01-05 | 广东石油化工学院 | PLC channel impulse noise detection method and system by utilizing curve stretching |
| CN114257357A (en) * | 2020-09-24 | 2022-03-29 | 珠海全志科技股份有限公司 | Method and device for detecting leader sequence signal |
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