PLC signal reconstruction method

Abstract

The invention relates to signal processing, in particular to a PLC (Programmable Logic Controller) signal reconstruction method, which comprises the following steps of: acquiring a signal sequence based on a time sequence; acquiring a second-order differential signal sequence of the signal sequence; calculating a transformation adjustment factor and a space factor according to the signal sequence and the second-order differential signal sequence; reconstructing the signal sequence according to the transformation adjustment factor and the space factor to obtain a first reconstructed signal sequence; calculating a delay length according to the signal sequence, and obtaining an L-mode differential signal sequence of the signal sequence; calculating an approximation sequence and a model matrix according to the signal sequence and the L-mode differential signal sequence; reconstructing the signal sequence according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence; comparing the signal-to-noise ratios of the first reconstructed signal sequence and the second reconstructed signal sequence, and selecting the reconstructed signal sequence with the larger signal-to-noise ratio as a PLC reconstructed signal; according to the technical scheme provided by the invention, the defect that the PLC signal reconstruction effect is relatively poor can be effectively overcome.

Description

Technical Field

[0001] The invention relates to signal processing, and in particular to a PLC signal reconstruction method. Background Art

[0002] Compared with various wired communication technologies, power line communication does not require rewiring, is easy to network, and has broad application prospects. Power line communication technology is divided into narrowband power line communication and broadband power line communication. Among them, narrowband power line communication refers to power line carrier communication technology with a bandwidth limited to 3 to 500kHz. Narrowband power line communication mostly uses single carrier modulation technology, such as PSK technology, DSSS technology, and linear frequency modulation Chirp technology, and the communication rate is less than 1Mbits / s; broadband power line communication refers to power line carrier communication technology with a bandwidth limited to 1.6 to 30MHz and a communication rate usually above 1Mbps, using a variety of spread spectrum communication technologies with OFDM as the core.

[0003] Although power line communication has a wide range of applications and the technology is relatively mature, compared with communication systems such as optical fiber, when PLC communication signals are transmitted through medium and low voltage power networks, due to the complex structure and numerous branches of the power network, especially the power network is not designed to transmit high-frequency communication signals, the complex electrical equipment in the power network will seriously interfere with the PLC communication signals, resulting in relatively serious data loss. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a PLC signal reconstruction method, which can effectively overcome the defect of poor PLC signal reconstruction effect in the prior art.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A PLC signal reconstruction method comprises the following steps:

[0009] S1, collect signal sequences based on time sequence;

[0010] S2, obtaining a second-order difference signal sequence of the signal sequence;

[0011] S3, calculating a transformation adjustment factor and a spatial factor according to the signal sequence and the second-order difference signal sequence;

[0012] S4, reconstructing the signal sequence according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence;

[0013] S5. Calculate the delay length according to the signal sequence, and obtain an L-mode differential signal sequence of the signal sequence;

[0014] S6, calculating an approximation sequence and a model matrix according to the signal sequence and the L-mode differential signal sequence;

[0015] S7, reconstructing the signal sequence according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence;

[0016] S8. Compare the signal-to-noise ratios of the first reconstructed signal sequence and the second reconstructed signal sequence, and select the reconstructed signal sequence with a larger signal-to-noise ratio as the PLC reconstructed signal.

[0017] Preferably, obtaining the second-order difference signal sequence of the signal sequence in S2 includes:

[0018] The first element ΔS in the second-order difference signal sequence ΔS 1 =0, the second element ΔS 2 =0, the nth element ΔS n =S n -S n-2 ;

[0019] Among them, S n is the nth element in the signal sequence S, S n-2 is the n-2th element in the signal sequence S, n∈[3,N], and N is the length of the signal sequence S.

[0020] Preferably, calculating the transformation adjustment factor according to the signal sequence and the second-order difference signal sequence in S3 includes:

[0021] The transformation adjustment factor γ is calculated using the following formula:

[0022]

[0023] Among them, ||S|| 1 L is the signal sequence S 1 norm, ||ΔS|| 1 L is the second-order differential signal sequence ΔS 1 Norm, MSE S is the mean square error of the signal sequence S, MSE ΔS is the mean square error of the second-order difference signal sequence ΔS.

[0024] Preferably, calculating the spatial factor according to the signal sequence and the second-order difference signal sequence in S3 includes:

[0025] The space factor η is calculated using the following formula:

[0026]

[0027] Among them, μ S is the mean of the signal sequence S, μ ΔS is the mean of the second-order difference signal sequence ΔS, Δf is the sampling frequency of the signal sequence S, and SNR is the signal-to-noise ratio of the signal sequence S.

[0028] Preferably, in S4, the signal sequence is reconstructed according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence, including:

[0029] The signal sequence S is reconstructed using the following formula to obtain the first reconstructed signal sequence S NEW1 :

[0030]

[0031] in, is the first reconstructed signal sequence S NEW1 The mth element in S m is the mth element in the signal sequence S, ΔS i-j is the i-jth element in the second-order differential signal sequence ΔS. When i-j≤0, ΔS i-j =0.

[0032] Preferably, calculating the delay length according to the signal sequence in S5 and obtaining an L-mode differential signal sequence of the signal sequence includes:

[0033] S51, calculate the delay length L using the following formula:

[0034]

[0035] in, Indicates rounding down modulo 2N;

[0036] S52, obtaining an L-mode differential signal sequence ΔS' of the signal sequence S based on the delay length L:

[0037] The first element ΔS' in the L-mode differential signal sequence ΔS' 1 =0, the qth element

[0038] in, Indicates rounding down with L as the modulus, S q-1 is the qth element in the signal sequence S.

[0039] Preferably, calculating the approximation sequence according to the signal sequence and the L-mode differential signal sequence in S6 includes:

[0040] The approximation sequence S' is calculated using the following formula:

[0041]

[0042] Among them, MSE ΔS' is the mean square error of the L-mode differential signal sequence ΔS'.

[0043] Preferably, in S6, calculating the approximation sequence and the model matrix according to the signal sequence and the L-mode differential signal sequence includes:

[0044] The model matrix Φ is calculated using the following formula:

[0045] Φ=Ψ(ΔS' T ·ΔS'+S T ·S);

[0046] Among them, Ψ is the model selection factor matrix.

[0047] Preferably, in S7, the signal sequence is reconstructed according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence, including:

[0048] The signal sequence S is reconstructed using the following formula to obtain the second reconstructed signal sequence S NEW2 :

[0049] S NEW2 =Φ(S'-λ·ΔS');

[0050] Among them, λ is the adjustment coefficient, max|S| is the element with the largest absolute value in the signal sequence S, and max|ΔS'| is the element with the largest absolute value in the L-mode differential signal sequence ΔS'.

[0051] (III) Beneficial effects

[0052] Compared with the prior art, the PLC signal reconstruction method provided by the present invention has the following beneficial effects:

[0053] 1) collecting a signal sequence based on a time sequence, obtaining a second-order differential signal sequence of the signal sequence, and calculating a transformation adjustment factor and a spatial factor according to the signal sequence and the second-order differential signal sequence, so that the signal sequence can be reconstructed according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence;

[0054] 2) calculating the delay length according to the signal sequence, and obtaining an L-mode differential signal sequence of the signal sequence, and calculating an approximation sequence and a model matrix according to the signal sequence and the L-mode differential signal sequence, so that the signal sequence can be reconstructed according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence;

[0055] 3) Finally, by comparing the signal-to-noise ratios of the first reconstructed signal sequence and the second reconstructed signal sequence, the reconstructed signal sequence with a larger signal-to-noise ratio is selected as the PLC reconstruction signal, which can effectively restore the integrity of the PLC signal and ensure that the signal receiver receives an accurate and complete signal, thereby making correct decisions and control actions, and ensuring the stability and reliability of the power network. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] A PLC signal reconstruction method, such as Figure 1 As shown, the following steps are included:

[0060] S1. Collect signal sequences based on time sequence.

[0061] S2. Obtaining a second-order differential signal sequence of the signal sequence, specifically comprising:

[0062] The first element ΔS in the second-order difference signal sequence ΔS 1 =0, the second element ΔS 2 =0, the nth element ΔS n =S n -S n-2 ;

[0063] Among them, S n is the nth element in the signal sequence S, S n-2 is the n-2th element in the signal sequence S, n∈[3,N], and N is the length of the signal sequence S.

[0064] S3. Calculating a transformation adjustment factor and a spatial factor according to the signal sequence and the second-order difference signal sequence, specifically including:

[0065] 1) The transformation adjustment factor γ is calculated using the following formula:

[0066]

[0067] Among them, ||S|| 1 L is the signal sequence S 1 norm, ||ΔS|| 1 L is the second-order differential signal sequence ΔS 1 Norm, MSE S is the mean square error of the signal sequence S, MSE ΔS is the mean square error of the second-order difference signal sequence ΔS;

[0068] 2) Calculate the space factor η using the following formula:

[0069]

[0070] Among them, μ S is the mean of the signal sequence S, μ ΔS is the mean of the second-order difference signal sequence ΔS, Δf is the sampling frequency of the signal sequence S, and SNR is the signal-to-noise ratio of the signal sequence S.

[0071] S4, reconstructing the signal sequence according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence, specifically including:

[0072] The signal sequence S is reconstructed using the following formula to obtain the first reconstructed signal sequence S NEW1 :

[0073]

[0074] in, is the first reconstructed signal sequence S NEW1 The mth element in S m is the mth element in the signal sequence S, ΔS i-j is the i-jth element in the second-order differential signal sequence ΔS. When i-j≤0, ΔS i-j =0.

[0075] The above technical scheme collects a signal sequence based on time sequence, obtains the second-order differential signal sequence of the signal sequence, calculates the transformation adjustment factor and the spatial factor according to the signal sequence and the second-order differential signal sequence, so that the signal sequence can be reconstructed according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence.

[0076] like Figure 1 As shown, S5, calculating the delay length according to the signal sequence, and obtaining the L-mode differential signal sequence of the signal sequence, specifically includes:

[0077] S51, calculate the delay length L using the following formula:

[0078]

[0079] in, Indicates rounding down modulo 2N;

[0080] S52, obtaining an L-mode differential signal sequence ΔS' of the signal sequence S based on the delay length L:

[0081] The first element ΔS' in the L-mode differential signal sequence ΔS' 1 =0, the qth element

[0082] in, Indicates rounding down with L as the modulus, S q-1 is the qth element in the signal sequence S.

[0083] S6. Calculating an approximation sequence and a model matrix according to the signal sequence and the L-mode differential signal sequence, specifically including:

[0084] 1) The approximation sequence S' is calculated using the following formula:

[0085]

[0086] Among them, MSE ΔS' is the mean square error of the L-mode differential signal sequence ΔS';

[0087] 2) Calculate the model matrix Φ using the following formula:

[0088] Φ=Ψ(ΔS' T ·ΔS'+S T ·S);

[0089] Among them, Ψ is the model selection factor matrix.

[0090] S7, reconstructing the signal sequence according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence, specifically comprising:

[0091] The signal sequence S is reconstructed using the following formula to obtain the second reconstructed signal sequence S NEW2 :

[0092] S NEW2 =Φ(S'-λ·ΔS');

[0093] Among them, λ is the adjustment coefficient, max|S| is the element with the largest absolute value in the signal sequence S, and max|ΔS'| is the element with the largest absolute value in the L-mode differential signal sequence ΔS'.

[0094] The above technical solution calculates the delay length according to the signal sequence, and obtains the L-mode differential signal sequence of the signal sequence, and calculates the approximation sequence and the model matrix according to the signal sequence and the L-mode differential signal sequence, so that the signal sequence can be reconstructed according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence.

[0095] S8. Compare the signal-to-noise ratios of the first reconstructed signal sequence and the second reconstructed signal sequence, and select the reconstructed signal sequence with a larger signal-to-noise ratio as the PLC reconstructed signal.

[0096] The above technical solution, by comparing the signal-to-noise ratio of the first reconstructed signal sequence and the second reconstructed signal sequence, selects the reconstructed signal sequence with a larger signal-to-noise ratio as the PLC reconstruction signal, which can effectively restore the integrity of the PLC signal and ensure that the signal receiver receives an accurate and complete signal, thereby making correct decisions and control actions, and ensuring the stability and reliability of the power network.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PLC signal reconstruction method, characterized in that: The following steps are involved: S1, collect signal sequences based on time sequence; S2, obtaining a second-order difference signal sequence of the signal sequence; S3, calculating a transformation adjustment factor and a spatial factor according to the signal sequence and the second-order difference signal sequence; S4, reconstructing the signal sequence according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence; S5. Calculate the delay length according to the signal sequence, and obtain an L-mode differential signal sequence of the signal sequence; S6, calculating an approximation sequence and a model matrix according to the signal sequence and the L-mode differential signal sequence; S7, reconstructing the signal sequence according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence; S8. Compare the signal-to-noise ratios of the first reconstructed signal sequence and the second reconstructed signal sequence, and select the reconstructed signal sequence with a larger signal-to-noise ratio as the PLC reconstructed signal.

2. The PLC signal reconstruction method according to claim 1, characterized in that: The second-order difference signal sequence of the signal sequence obtained in S2 includes: The first element ΔS1 of the second-order differential signal sequence ΔS is 0, the second element ΔS2 is 0, and the nth element ΔS n =S n -S n-2 ; Among them, S n is the nth element in the signal sequence S, S n-2 is the n-2th element in the signal sequence S, n∈[3,N], and N is the length of the signal sequence S.

3. The PLC signal reconstruction method according to claim 2, characterized in that: In S3, the transformation adjustment factor is calculated according to the signal sequence and the second-order difference signal sequence, including: The transformation adjustment factor γ is calculated using the following formula: Among them, ||S||1 is the L1 norm of the signal sequence S, ||ΔS||1 is the L1 norm of the second-order difference signal sequence ΔS, and MSE S is the mean square error of the signal sequence S, MSE ΔS is the mean square error of the second-order difference signal sequence ΔS.

4. The PLC signal reconstruction method according to claim 3, characterized in that: In S3, the spatial factor is calculated according to the signal sequence and the second-order difference signal sequence, including: The space factor η is calculated using the following formula: Among them, μ S is the mean of the signal sequence S, μ ΔS is the mean of the second-order difference signal sequence ΔS, Δf is the sampling frequency of the signal sequence S, and SNR is the signal-to-noise ratio of the signal sequence S.

5. The PLC signal reconstruction method according to claim 4, characterized in that: In S4, the signal sequence is reconstructed according to the transformation adjustment factor and the spatial factor to obtain a first reconstructed signal sequence, including: The signal sequence S is reconstructed using the following formula to obtain the first reconstructed signal sequence S NEW1 : in, is the first reconstructed signal sequence S NEW1 The mth element in S m is the mth element in the signal sequence S, ΔS i-j is the i-jth element in the second-order differential signal sequence ΔS. When i-j≤0, ΔS i-j =0.

6. The PLC signal reconstruction method according to claim 4, characterized in that: In S5, the delay length is calculated according to the signal sequence, and an L-mode differential signal sequence of the signal sequence is obtained, including: S51, calculate the delay length L using the following formula: in, Indicates rounding down modulo 2N; S52, obtaining an L-mode differential signal sequence ΔS' of the signal sequence S based on the delay length L: The first element ΔS'1 in the L-mode differential signal sequence ΔS' is 0, and the qth element in, Indicates rounding down with L as the modulus, S q-1 is the qth element in the signal sequence S.

7. The PLC signal reconstruction method according to claim 6, characterized in that: In S6, the approximation sequence is calculated according to the signal sequence and the L-mode differential signal sequence, including: The approximation sequence S' is calculated using the following formula: Among them, MSE ΔS' is the mean square error of the L-mode differential signal sequence ΔS'.

8. The PLC signal reconstruction method according to claim 7, characterized in that: In S6, the approximation sequence and the model matrix are calculated according to the signal sequence and the L-mode differential signal sequence, including: The model matrix Φ is calculated using the following formula: Φ=Ψ(ΔS' T ·ΔS'+S T ·S); Among them, Ψ is the model selection factor matrix.

9. The PLC signal reconstruction method according to claim 8, characterized in that: In S7, the signal sequence is reconstructed according to the approximation sequence, the model matrix and the L-mode differential signal sequence to obtain a second reconstructed signal sequence, including: The signal sequence S is reconstructed using the following formula to obtain the second reconstructed signal sequence S NEW2 : S NEW2 =Φ(S'-λ·ΔS'); Among them, λ is the adjustment coefficient, max|S| is the element with the largest absolute value in the signal sequence S, and max|ΔS'| is the element with the largest absolute value in the L-mode differential signal sequence ΔS'.

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