Power line carrier communication system pulse suppression method for detecting pulse noise

Abstract

The invention provides a power line carrier communication system pulse suppression method for detecting pulse noise, which comprises the following steps of: 1, calculating a rough estimation threshold value according to the energy of a received signal; step 2, calculating the position of impulse noise according to the roughly estimated threshold value; step 3, according to the position of the pulse noise obtained in the step 2 and the received signal in the step 1, calculating a time domain signal of the pulse noise by adopting a pulse suppression method, and performing burr elimination processing; and step 4, according to the time domain signal of the pulse noise, performing pulse suppression operation on the received signal to complete pulse suppression of the power line carrier communication system.

Description

Technical Field

[0001] The invention relates to a pulse suppression method, in particular to a pulse suppression method for a power line carrier communication system for detecting pulse noise. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] In power line carrier communication systems, pulse noise is a common interference source. The following factors usually affect its generation probability and amplitude: 1. Climate conditions: The probability of pulse generation is higher in thunderstorm seasons and the amplitude is higher. In dry seasons, there is a lack of corona discharge and the probability of pulse generation is relatively low; 2. Geographical location: The probability of pulse generation is high in mountainous areas and areas with many trees, and low in plains; 3. The operation status of the power system: such as switch operation, fault tripping, etc. will generate transient low electromagnetic pulses to increase the probability of pulse noise; 4. Power line characteristics; 5. Human activities, etc. Pulse noise will directly affect the normal signal transmission of the communication system. Due to the randomness of the pulse signal and the uncertainty of the amplitude, it is difficult to identify the noise. Generally, the system will consider designing a reasonable threshold value to detect the position of the pulse noise, and consider using clipping technology to eliminate the pulse signal. However, how to design a reasonable threshold value is the difficulty of pulse suppression, and clipping technology will also cause signal distortion. Therefore, this solution considers technical innovation in these two aspects, designs a more reasonable threshold value, and has more accurately calculated the pulse noise position and amplitude for pulse suppression processing.

[0004] The implementation schemes similar to the present invention are based on the characteristics of empty subcarriers that there is noise but no data information, and the compressed sensing method is used to reconstruct the pulse noise. The schemes are specifically divided into the following categories: The first category: based on inserting a limited number of pilot subcarriers into the frequency domain response of OFDM symbols for channel estimation for pulse suppression. This type of method can effectively find the pulse noise point and pulse amplitude, but according to the current low-voltage power line carrier communication protocol regulations at home and abroad, there is no provision for inserting a limited number of pilot points in an OFDM frequency domain symbol. Although there is an option to add pilot symbols in IEEE1901.1, it is only for inserting a whole pilot OFDM symbol in multiple data OFDM symbols. The generation of pulses in the power line channel is random, and the pulse noise in the data symbol cannot be solved by the pulse noise estimated by the pilot symbols at different times. Therefore, this method is not available in the current protocol; the second type is to use compressed sensing reconstruction technology for the signal in the empty subcarrier, and estimate the pulse noise signal by regularizing the decision conditions, weighted smoothing L0, threshold decision, and Turbo-like ideas. The receiving end uses the received signal minus the estimated pulse noise to finally achieve the effect of pulse suppression. This type of idea is based on Bayesian theory and is optimized and improved to make the pulse estimation approach the actual value. This type of method is very dependent on the threshold setting in the system, and the performance effects vary greatly. The third type: setting a threshold, directly setting the part of the time domain signal that exceeds the threshold to zero. If the threshold is set too high, this method cannot detect all pulse noise. If it is set too low, a large number of non-pulse signals will be set to zero, resulting in too many OFDM symbol zero points affecting the system transmission performance.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for pulse suppression of a power line carrier communication system for detecting pulse noise in view of the deficiencies in the prior art.

[0007] In order to solve the above technical problems, the present invention discloses a method for pulse suppression of a power line carrier communication system for detecting pulse noise, comprising:

[0008] Step 1, calculating a rough estimate threshold according to the energy of the received signal;

[0009] Step 2, calculating the position of the impulse noise according to the rough estimation threshold;

[0010] Step 3, according to the position of the impulse noise obtained in step 2 and the received signal described in step 1, a pulse suppression method is used to calculate the time domain signal of the impulse noise and perform burr elimination processing;

[0011] Step 4: Perform a pulse suppression operation on the received signal according to the time domain signal of the pulse noise to complete the pulse suppression of the power line carrier communication system.

[0012] Furthermore, the calculation of the rough estimation threshold in step 1 specifically includes:

[0013]

[0014] Wherein, th is the rough estimation threshold, p is the generation probability of the impulse noise, P avg is the energy mean of the received signal.

[0015] Furthermore, the rough estimation threshold th described in step 1 is simplified to be calculated as follows in the power line carrier communication system:

[0016] th=2*P avg .

[0017] Furthermore, the calculation of the position of the impulse noise in step 2 specifically includes:

[0018] Ω={n||y t,n | 2 >th n=0,1,...,N-1}

[0019] Wherein, Ω is the position of the impulse noise, that is, the sequence number set of the impulse noise after the rough estimation threshold calculation in step 1, y t is the time domain signal of the received signal, n is the sequence number of the time domain signal, and N is the number of time domain symbol points after orthogonal frequency division multiplexing OFDM removes cyclic redundancy.

[0020] Furthermore, the step of calculating the time domain signal of the impulse noise in step 3 specifically includes:

[0021] Step 3-1, calculate the time domain signal IN of the initialization impulse noise est , as follows:

[0022]

[0023] Where Ψ is the real Fourier transform matrix, (·) + represents the inverse matrix operation, Y A is the frequency domain received signal on the null subcarrier, | Ω Indicates that all positions except the Ω position are set to zero. To match the full subcarrier energy, M is the total number of carriers, MA is the number of empty subcarrier sequences;

[0024] Step 3-2, compare the time domain signal IN of the initialization pulse noise calculated in step 3-1 est0 The absolute value of the amplitude is the same as the time domain signal y of the received signal described in step 1 t If the absolute value of the amplitude is greater than, the domain signal IN est After setting to zero, go to step 3-3, otherwise go directly to step 3-3;

[0025] Step 3-3, calculate the estimated value of the received signal after pulse suppression processing The details are as follows:

[0026]

[0027] Set the number of iterations, perform loop iterations, and obtain the estimated value IN of the time domain signal of the impulse noise est , complete the iterative reconstruction operation of impulse noise;

[0028] Step 3-4, performing burr elimination on the pulse noise obtained after completing the iterative reconstruction operation to obtain the final time domain signal IN of the pulse noise for performing the pulse suppression operation est .

[0029] Furthermore, the iterative loop described in step 3-3 specifically includes:

[0030] Step 3-3-1, calculate the new impulse noise position C, as follows:

[0031]

[0032] in, Represents the estimated value from the received signal Select the K largest modulus values ​​and use the received signal estimate The corresponding K values ​​in are taken as the result;

[0033] Step 3-3-2, calculate the frequency domain value of the received signal in step 3-3-2 in the empty subcarrier The details are as follows:

[0034]

[0035] Among them, | A It means that except for the value assigned to position A, all other positions are set to zero;

[0036] Step 3-3-3, calculate the precise estimated pulse signal IN est1 , as follows:

[0037]

[0038] Among them, + represents the inverse Fourier matrix transform;

[0039] Step 3-3-4, based on the precise estimation of pulse signal IN es Calculate the accurate estimate of the received signal value The details are as follows:

[0040]

[0041] Step 3-3-5, calculate the frequency domain value The details are as follows:

[0042]

[0043] Step 3-3-6, calculate the frequency domain value The energy ratio of data carrier and null subcarrier The details are as follows:

[0044]

[0045] in, Represents frequency domain value The energy of the data carrier, represents the energy of the null subcarrier;

[0046] Step 3-3-7, compare the ratio The judgment is as follows:

[0047] Set the decision condition P th , the judgment is as follows:

[0048] like Then the iterative loop is jumped out, and the time domain signal estimation of the received signal after the pulse suppression method is for:

[0049]

[0050] Impulse Noise Estimation IN est for:

[0051]

[0052] like Then the received signal value is accurately estimated The time domain signal of the received signal to be adjusted returns to step 3-3-1 to continue iterating, and this value is used as the initial value of the time domain signal Repeat steps 3-3-1 to 3-3-7 until it is determined that the iteration loop is exited or the upper limit of the number of iterations is exceeded, completing the iterative reconstruction operation of the impulse noise.

[0053] Furthermore, the number of iterations described in step 3-3 is set to 10.

[0054] Furthermore, the judgment condition P described in step 3-3-7 th , the calculation method is as follows:

[0055] Assume that the time domain signal obtained after the pulse suppression operation of the received signal is The corresponding frequency domain signal is There is only background white noise energy in the empty subcarrier, and the data carrier contains the sum of data energy and background white noise energy. The signal-to-noise ratio in the communication system is recorded as SNR dB , data energy is P info , the noise energy is P AWGN , calculate the energy ratio P of data carrier and empty subcarrier rate , as follows:

[0056]

[0057] The decision conditions are set as follows:

[0058] P th =P rate ×0.9.

[0059] Furthermore, the burr elimination described in step 3-4 is performed, that is, all impulse noises smaller than the time domain signal mean value of the received signal are set to zero.

[0060] Further, the pulse suppression operation on the received signal described in step 4 specifically includes:

[0061]

[0062] in, is the time domain signal obtained after the pulse suppression operation, and y is the time domain signal to be subjected to the pulse suppression operation.

[0063] Beneficial effects:

[0064] 1. It can suppress the pulse noise of the system without pilot signal to a certain extent, because the pulse position detected by the threshold value designed based on the signal-to-noise ratio is adaptively matched based on the compressed sensing technology, and the system does not need to provide more parameters to estimate the pulse signal.

[0065] 2. Due to the iterative calculation of pulse noise, the system allows a larger pulse probability to be generated, that is, under more pulse points, the system can still identify the pulse noise and play a suppressive effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0067] Figure 1 It is a system framework diagram of the present invention.

[0068] Figure 2 This is a schematic diagram of pulse noise amplitude comparison when the number of pulse points is 10.

[0069] Figure 3 This is a schematic diagram of pulse noise amplitude comparison when the number of pulse points is 30.

[0070] Figure 4 This is a schematic diagram of pulse noise amplitude comparison when the number of pulse points is 50.

[0071] Figure 5 This is a schematic diagram of pulse noise amplitude comparison when the number of pulse points is 100.

[0072] Figure 6 This is a schematic diagram of bit error rate comparison when the number of pulse points is 10.

[0073] Figure 7 This is a schematic diagram of bit error rate comparison when the number of pulse points is 30.

[0074] Figure 8 This is a schematic diagram of bit error rate comparison when the number of pulse points is 50.

[0075] Fig. 9 This is a schematic diagram of bit error rate comparison when the number of pulse points is 100. DETAILED DESCRIPTION

[0076] The main principles of the present invention are as follows:

[0077] The present invention mainly collects and processes received signals and identifies the specific position and amplitude of pulse signals in the time domain by setting a reasonable threshold value. Before the signal enters the channel estimation process, the pulse of the received signal is eliminated, which completely solves the signal distortion, high bit error rate and stability reduction caused by pulse noise on the system, thereby improving the reliability of the system.

[0078] According to the "Dual-mode Communication Interoperability Specification", the present invention has the conditions to calculate the judgment condition based on the energy ratio of the empty subcarrier and the data carrier and reconstruct the pulse signal through compressed sensing. The received signal at the receiving end removes the reconstructed pulse signal to achieve the effect of pulse suppression. The specific implementation steps are three steps: the first step is to calculate a rough estimate threshold for the received signal energy; the second step is based on the characteristics of the empty subcarrier in power line carrier communication, which only has noise energy, and the rough estimate threshold calculated in the first step is used to calculate the estimated value and position of the pulse signal through compressed sensing technology. The pulse estimate is subtracted from the original received signal to obtain the current received signal estimate, and the energy threshold is calculated according to the energy ratio of the empty subcarrier and the data carrier. When the received signal estimate after processing passes the energy threshold judgment, it means that the pulse estimation is accurate. If it does not pass the judgment, repeat the second step; the third step is to remove the excessively small value based on the pulse estimate obtained in the second step to obtain an accurate pulse estimate, and subtract the estimate from the received signal to obtain the received signal after pulse suppression processing.

[0079] The specific technical solutions of the present invention are as follows:

[0080] (1) System overall model

[0081] like Figure 1 As shown, the transmitting end generates a QPSK (Quadrature Phase Shift Keying) frequency domain signal X, and obtains a complete OFDM (Orthogonal Frequency Division Multiplexing) symbol x after inverse fast Fourier transform IFFT and adds cyclic redundancy (+CP), passes through the power line carrier communication channel (Channel) and adds background Gaussian white noise (Additive White Gaussian Noise, AWGN) and impulse noise (Impulsive Noise), and removes cyclic redundancy (-CP) at the receiving end to obtain the original time domain received signal y. A processed time domain received signal is obtained by the noise suppression method (IN mitigation) proposed in the present invention. The frequency domain received signal is obtained by fast Fourier transform (FFT) Finally, the received signal required by the system is obtained through QPSK-based demodulation (Demod).

[0082] (2) Rough estimation threshold

[0083] The rough estimation threshold is to initially estimate the position of the impulse noise by means of energy limitation. It is designed as follows:

[0084]

[0085] Where p is the probability of pulse signal generation, P avg is the energy mean of the received signal. Based on the test stress of the State Grid, the pulse signal generated is 100kHz and lasts for 1us. It can be roughly calculated that the probability of the pulse signal is about 0.1, so the above rough estimate threshold is approximately equal to th = 2*P avg Then the initialization noise position before the compressed sensing reconstruction noise of the present invention can be obtained:

[0086] Ω={n||y t,n | 2 >th n=0,1,...,N-1}

[0087] Among them, y t is the received time domain signal, n is the sequence number of the time domain signal, N is the number of time domain symbol points after OFDM removes cyclic redundancy, and Ω is the sequence number set of impulse noise after rough estimation.

[0088] (3) Improved sparse adaptive matching pursuit (OP-SAMP) to reconstruct the noise signal

[0089] This technique uses the above-calculated rough estimate of the impulse noise time position set Ω and the received time domain signal y t The pulse noise time domain signal IN is finally estimated through the pulse suppression algorithm. est The specific algorithm flow is:

[0090] Input: time domain received signal y t ; Frequency domain received signal Y; Roughly estimated impulse noise time position set Ω; K represents the length of the set Ω; The total number of carriers is recorded as M; The set of empty subcarrier sequences is A; The number is recorded as M A ; The data carrier sequence set is S; the number is M S ; Real Fourier transform matrix Ψ; (·) + It is expressed as an inverse matrix operation; max(v,T) means selecting T largest modulus values ​​from vector v and taking the corresponding T values ​​in v as the result; the energy ratio decision condition P of the data carrier and the empty subcarrier th .

[0091] Initialization: Calculate the initialization pulse signal:

[0092]

[0093] Among them, Y A A frequency domain received signal on a null subcarrier; To match the full subcarrier energy, except for the Ω position, all other positions are set to zero. The initialization pulse signal result and the time domain received signal y tFor comparison, if the absolute value of the estimated pulse is higher than the absolute value of the received signal, it means that the estimation is wrong, then the estimated pulse value at this point is set to zero and the next estimation is performed.

[0094] Calculate the received signal estimate after pulse suppression Enter iterative reconstruction, and set the upper limit of iteration to 10.

[0095]

[0096] Iteration:

[0097] ① Update the impulse noise position collection C:

[0098]

[0099] ② Calculate and estimate the frequency domain value of the received signal in the empty subcarrier

[0100]

[0101] ③ Calculate the estimated pulse signal IN est1 :

[0102]

[0103] ④ Calculate the received signal value after precise estimation

[0104]

[0105] ⑤Calculate frequency domain value

[0106]

[0107] ⑥ Calculate the energy ratio of the estimated data carrier and the empty subcarrier

[0108]

[0109] ⑦ Judge the energy ratio and set the judgment condition P th ,like The received time domain signal to be adjusted is returned and iterated to become the initial value of the time domain signal Repeat ① to ⑥ until Or if the upper limit of the number of iterations is exceeded, the iterative reconstruction operation of the pulse signal is completed. The received time domain signal after the pulse suppression algorithm is estimated to be:

[0110]

[0111] The pulse signal is estimated as:

[0112]

[0113] ⑧ After jumping out of the iteration loop, the pulse signal with too small value is eliminated, and all pulse signals with less than the mean value of the received time domain signal before the pulse suppression processing are set to zero. The last step of pulse signal estimation is completed. At this time, the pulse signal IN est Perform pulse suppression on the received signal as the final pulse signal estimate:

[0114]

[0115] in, is the time domain signal after the pulse suppression operation, and y is the time domain signal before the pulse suppression operation.

[0116] (4) Judgment Condition P th Calculation method

[0117] The time domain signal obtained after the pulse suppression processing of the known received signal The corresponding frequency domain signal is There is only background white noise energy in the empty subcarrier, and the data carrier contains the sum of data energy and background white noise energy. The known system SNR can be calculated from the leading symbol and recorded as SNR dB , data energy is P info , the noise energy is P AWGN , the energy ratio P of the data carrier and the empty subcarrier can be calculated rate :

[0118]

[0119] The simulation data shows that the energy ratio will partially fluctuate due to the randomness of the noise, and a certain error is allowed after the pulse suppression process. After comprehensive verification, the decision condition can be:

[0120] P th =P rate ×0.9.

[0121] In summary, the key points of the present invention are divided into the following aspects:

[0122] 1. Aiming at the characteristic of the SAMP algorithm for reconstructing noise signals that the empty subcarrier contains only noise, the amplitude of the reconstructed impulse noise is continuously adjusted through the iterative algorithm of time-frequency conversion to improve its estimation accuracy.

[0123] 2. The SNR obtained by the SNR numerical calculation module provided by the preamble calculates the energy ratio of the data carrier segment and the empty subcarrier segment. By comparing the ratio value of the pulse signal after the received signal is eliminated and reconstructed, it can be determined whether the reconstructed pulse signal is accurate.

[0124] 3. The final pulse signal is estimated through the initial rough estimation threshold and the final glitch elimination threshold to avoid misjudging non-pulse signals with large amplitudes during signal reconstruction. Similarly, pulse signals with small amplitudes can be appropriately ignored because they have little impact on the system.

[0125] like Figures 2 to 5 As shown, a comparison chart of pulse noise with different pulse point numbers (10, 30, 50, 100) estimated based on the optimization algorithm and the actual pulse noise is shown. The horizontal axis is the time domain point position of the pulse noise changing over time, and the vertical axis is the amplitude. The line segment (with "o") represents the actual value of the simulated pulse noise model, and the line segment (with "x") represents the pulse noise estimation value reconstructed by the method of the present invention. It can be clearly seen that as the number of pulse points changes from small to large, the system can still accurately estimate the position and amplitude of the pulse signal. When the number of pulse points is 100, there will be a small number of pulse points with very small amplitudes that are not estimated. These pulses have little effect on the stability of the system and can be ignored.

[0126] like Figures 6 to 9 As shown, a comparison chart of bit error rates after adding pulse noise of different numbers of points to a PLC system modeled in one embodiment is shown. The horizontal axis represents the system signal-to-noise ratio (dB), and the vertical axis represents the system bit error rate. It includes a signal without pulse noise (as shown by the line segment with "*" in the figure), a received signal of an ideal suppression method that sets the actual pulse point position to zero (as shown by the line segment with "□" in the figure), a received signal with coarse estimated pulse noise zero suppression (as shown by the line segment with "◇"), and a received signal with pulse suppression by an optimized algorithm (as shown by the line segment with "o"). The results in the figure below show that as the number of pulse points increases, the performance of the three pulse suppression methods all attenuate to varying degrees. Among them, the coarse estimation threshold suppression method basically has no optimization effect on the system after the pulse point exceeds 30 points. The performance of the optimization algorithm gradually approaches the pulse suppression result under ideal conditions as the number of pulse points increases. At BER=10 -3 When the number of pulse points is 10, the performance of the two methods is about 2.5dB worse; when the number of pulse points is 30, the performance of the two methods is about 2dB worse; when the number of pulse points is 50, the performance of the two methods is about 1dB worse. When the number of pulse points is 100, the overall sensitivity of the system to pulses is high, and the results of the optimization algorithm are still close to the ideal suppression method.

[0127] In a specific implementation, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, and when the computer program is executed by the data processing unit, the invention content of the method for pulse suppression of a power line carrier communication system for detecting pulse noise provided by the present invention and some or all steps in each embodiment can be run. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0128] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present invention can be implemented by means of computer programs and their corresponding general hardware platforms. Based on such an understanding, the technical solutions in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of computer programs, i.e., software products, which can be stored in a storage medium and include several instructions for enabling a device including a data processing unit (which can be a personal computer, a server, a single-chip microcomputer, an MCU or a network device, etc.) to execute the methods described in various embodiments of the present invention or certain parts of the embodiments.

[0129] The present invention provides a method and method for detecting pulse noise in a power line carrier communication system pulse suppression. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for pulse suppression in a power line carrier communication system for detecting pulse noise, characterized in that: include: Step 1, calculating a rough estimate threshold according to the energy of the received signal; Step 2, calculating the position of the impulse noise according to the rough estimation threshold; Step 3, according to the position of the impulse noise obtained in step 2 and the received signal described in step 1, a pulse suppression method is used to calculate the time domain signal of the impulse noise and perform burr elimination processing; Step 4: Perform a pulse suppression operation on the received signal according to the time domain signal of the pulse noise to complete the pulse suppression of the power line carrier communication system.

2. A method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 1, characterized in that: The calculation of the rough estimate threshold described in step 1 specifically includes: Wherein, th is the rough estimation threshold, p is the generation probability of the impulse noise, P avg is the energy mean of the received signal.

3. The method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 2, characterized in that: The rough estimation threshold th in step 1 is simplified to be calculated as follows in the power line carrier communication system: th=2*P avg 。 4. The method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 1, characterized in that: The calculation of the position of the impulse noise described in step 2 specifically includes: Ω={n||y t,n | 2 >th n=0,1,...,N-1} Wherein, Ω is the position of the impulse noise, that is, the sequence number set of the impulse noise after the rough estimation threshold calculation in step 1, y t is the time domain signal of the received signal, n is the sequence number of the time domain signal, and N is the number of time domain symbol points after orthogonal frequency division multiplexing OFDM removes cyclic redundancy.

5. The method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 2, characterized in that: The step 3 of calculating the time domain signal of the impulse noise specifically includes: Step 3-1, calculate the time domain signal IN of the initialization impulse noise est0 , as follows: Where Ψ is the real Fourier transform matrix, (·) + represents the inverse matrix operation, Y A is the frequency domain received signal on the null subcarrier, | Ω Indicates that all positions except the Ω position are set to zero. To match the full subcarrier energy, M is the total number of carriers, M A is the number of empty subcarrier sequences; Step 3-2, compare the time domain signal IN of the initialization pulse noise calculated in step 3-1 est0 The absolute value of the amplitude is the same as the time domain signal y of the received signal described in step 1 t If the absolute value of the amplitude is greater than, the domain signal IN est0 After setting to zero, go to step 3-3, otherwise go directly to step 3-3; Step 3-3, calculate the estimated value of the received signal after pulse suppression processing The details are as follows: Set the number of iterations, perform loop iterations, and obtain the estimated value IN of the time domain signal of the impulse noise est , complete the iterative reconstruction operation of impulse noise; Step 3-4, performing burr elimination on the pulse noise obtained after completing the iterative reconstruction operation to obtain the final time domain signal IN of the pulse noise for performing the pulse suppression operation est .

6. A method for pulse suppression in a power line carrier communication system for detecting pulse noise according to claim 5, characterized in that: The iterative loop described in step 3-3 specifically includes: Step 3-3-1, calculate the new impulse noise position C, as follows: in, Represents the estimated value from the received signal Select the K largest modulus values ​​and use the received signal estimate The corresponding K values ​​in are taken as the result; Step 3-3-2, calculate the frequency domain value of the received signal in step 3-3-2 in the empty subcarrier The details are as follows: Among them, | A It means that except for the value assigned to position A, all other positions are set to zero; Step 3-3-3, calculate the precise estimated pulse signal IN est1 , as follows: Among them, + represents the inverse Fourier matrix transform; Step 3-3-4, based on the precise estimation of pulse signal IN est1 Calculate the accurate estimate of the received signal value The details are as follows: Step 3-3-5, calculate the frequency domain value The details are as follows: Step 3-3-6, calculate the frequency domain value The energy ratio of data carrier and null subcarrier The details are as follows: in, Represents frequency domain value The energy of the data carrier, represents the energy of the null subcarrier; Step 3-3-7, compare the ratio The judgment is as follows: Set the decision condition P th , the judgment is as follows: like Then the iterative loop is jumped out, and the time domain signal estimation of the received signal after the pulse suppression method is for: Impulse Noise Estimation IN est for: like Then the received signal value is accurately estimated The time domain signal of the received signal to be adjusted returns to step 3-3-1 to continue iterating, and this value is used as the initial value of the time domain signal Repeat steps 3-3-1 to 3-3-7 until it is determined that the iteration loop is exited or the upper limit of the number of iterations is exceeded, completing the iterative reconstruction operation of the impulse noise.

7. A method for pulse suppression in a power line carrier communication system for detecting pulse noise according to claim 6, characterized in that: The number of iterations described in step 3-3 is set to 10.

8. The method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 7, characterized in that: The decision condition P described in step 3-3-7 th , the calculation method is as follows: Assume that the time domain signal obtained after the pulse suppression operation of the received signal is The corresponding frequency domain signal is There is only background white noise energy in the empty subcarrier, and the data carrier contains the sum of data energy and background white noise energy. The signal-to-noise ratio in the communication system is recorded as SNR db , data energy is P info , the noise energy is P AWGN , calculate the energy ratio P of data carrier and empty subcarrier rate , as follows: The decision conditions are set as follows: P th =P rate ×0.9。 9. A method for pulse suppression in a power line carrier communication system for detecting pulse noise according to claim 8, characterized in that: The burr elimination described in step 3-4 is to set all impulse noises smaller than the time domain signal mean value of the received signal to zero.

10. The method for pulse suppression of a power line carrier communication system for detecting pulse noise according to claim 9, characterized in that: The pulse suppression operation on the received signal described in step 4 specifically includes: in, is the time domain signal obtained after the pulse suppression operation, and y is the time domain signal to be subjected to the pulse suppression operation.

Images