Frame synchronization method and device for broadband power line communication

Abstract

The invention relates to the technical field of power line communication, and discloses a frame synchronization method and device for broadband power line communication, and the method comprises the steps: carrying out the symbolization cross-correlation operation of a received signal, and obtaining a cross-correlation result sequence; performing secondary autocorrelation analysis and accumulation processing on the cross-correlation values in the sequence to generate an autocorrelation accumulated value sequence; screening candidate peak positions according to absolute values of the self-correlation accumulated values; defining a synchronous peak analysis window around the candidate peak position, and setting a noise reference window in an area far away from the window; verifying the validity of the candidate peak based on the difference between the autocorrelation accumulated values of the synchronization peak window and the noise reference window; and if the verification is valid, calculating and determining a final synchronization position through a mean value of a plurality of peak value positions in the synchronization peak window. According to the method, the problem of inaccurate synchronization peak positioning under the multipath effect and noise interference in the existing method is solved through the self-correlation accumulation and noise separation mechanism, and the reliability of frame synchronization is improved.

Description

Technical Field

[0001] This application relates to the field of power line communication technology, and particularly to a frame synchronization method and device for broadband power line communication. Background Art

[0002] In a broadband power line communication system, frame synchronization is a core link for realizing reliable data transmission. Existing technologies usually complete synchronization through cross-correlation peak detection between the received signal and the local sequence. However, there are multipath effects and strong noise interference in the power line channel, resulting in the dispersion of synchronization peak energy. Traditional methods rely on single cross-correlation peak detection and fixed threshold determination, making it difficult to accurately distinguish effective signals from noise, and prone to synchronization offset or misjudgment.

[0003] Therefore, there is an urgent need for a frame synchronization method that can suppress the influence of multipath interference and noise to solve the problem of reduced synchronization accuracy caused by the dispersion of synchronization peak energy and noise interference in the existing technology. Summary of the Invention

[0004] In view of this, this application provides a frame synchronization method and device for broadband power line communication to solve the problem of reduced synchronization accuracy caused by the dispersion of synchronization peak energy and noise interference in the existing technology. The technical solution is as follows.

[0005] In a first aspect, this application provides a frame synchronization method for broadband power line communication, and the method includes: Performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence; Performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence in turn to generate an autocorrelation accumulation value sequence; Determining candidate peak positions based on the absolute values of the autocorrelation accumulation values in the autocorrelation accumulation value sequence; Determining a synchronization peak window centered on the candidate peak position, and determining a noise evaluation window in a region without overlap with the synchronization peak window; Judging the effectiveness of the candidate peak based on the autocorrelation accumulation values within the synchronization peak window and the autocorrelation accumulation values within the noise evaluation window; If it is judged to be effective, determining the target synchronization peak position according to the average value of the peak positions within the synchronization peak window to complete frame synchronization.

[0006] The frame synchronization method for broadband power line communication provided by this application generates a cross-correlation sequence through symbol cross-correlation calculation, avoiding the multiplication operation in traditional cross-correlation operations, and significantly reducing the computational complexity; further performing autocorrelation calculation on the cross-correlation values and accumulating them to generate an autocorrelation accumulation value sequence, using autocorrelation operation to amplify the characteristics of the effective signal, and combining the accumulation operation to suppress noise fluctuations, enhancing the significance of the synchronization peak; dynamically determining the candidate peak position through absolute value, avoiding interference from negative correlation values of noise, and improving the accuracy of candidate peak detection; dividing the synchronization peak window and the noise evaluation window centered on the candidate peak, separating the signal energy and noise samples, and providing a reliable basis for effectiveness determination; determining the effectiveness of the candidate peak based on the comparison of the autocorrelation accumulation values of the synchronization peak window and the noise evaluation window, effectively excluding the interference of false peaks; finally, determining the target synchronization peak through the average calculation of the multi-peak positions within the synchronization peak window, weakening the single-peak offset error, and improving the synchronization positioning accuracy. The method of this application significantly improves the synchronization accuracy, anti-interference ability, and reliability in power line communication under multipath effects and noise environments.

[0007] In an alternative embodiment, performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence includes: Performing symbolization processing on the received signal to obtain symbol data retaining the amplitude; Performing addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence.

[0008] The frame synchronization method for broadband power line communication provided by this application, the symbol cross-correlation calculation includes performing addition and subtraction operations on the symbolized (retaining the amplitude symbol) received signal and the local synchronization preamble to generate a cross-correlation sequence. By replacing the traditional multiplication operation with symbolization processing, the cross-correlation calculation is simplified to addition and subtraction operations, significantly reducing the computational complexity, while retaining the signal characteristic information, ensuring the real-time performance and hardware implementation efficiency of synchronization peak detection.

[0009] In an alternative embodiment, the local synchronization preamble sequence is a pre-stored periodic reference sequence, and the number of sampling points of the local synchronization preamble sequence is the same as that of the synchronization preamble sequence of the received signal.

[0010] The frame synchronization method for broadband power line communication provided by this application ensures the matching and integrity of the symbol cross-correlation calculation by pre-storing a local sequence with the same length as the preamble of the received signal, avoiding the leakage or misdetection of synchronization peak energy caused by sequence length deviation, and improving the accuracy of the cross-correlation result.

[0011] In an alternative embodiment, performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence in sequence to generate an autocorrelation accumulation value sequence includes: Performing a multiplication operation on the current cross-correlation value and the historical cross-correlation value at a preset interval before to obtain an autocorrelation result; Accumulate the autocorrelation results within a preset window range to obtain an autocorrelation accumulation value sequence; the preset window range covers the maximum number of sampling points corresponding to the multipath delay.

[0012] The frame synchronization method for broadband power line communication provided by this application amplifies the autocorrelation of the effective signal through product operation, and combines window accumulation to suppress the random interference of multipath delay and noise, making the synchronization peak energy concentrated and significant, and improving the accuracy of synchronization peak detection.

[0013] In an optional implementation manner, determining the candidate peak position based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence includes: Traverse the autocorrelation accumulation value sequence based on a preset initial threshold value; When it is detected that the absolute value of the autocorrelation accumulation value first exceeds the initial threshold value, update the threshold value with the absolute value of the current autocorrelation accumulation value, and record the current position as the candidate peak position; Continue to traverse the autocorrelation accumulation value sequence backward. If it is detected later that the absolute value of the autocorrelation accumulation value exceeds the updated threshold value, update the threshold value with a larger absolute value, and update the candidate peak position to the current detection position; When no larger absolute value of autocorrelation accumulation is detected within a continuous preset number of sampling points, stop traversing and obtain the final candidate peak position.

[0014] The frame synchronization method for broadband power line communication provided by this application adapts to the change of the noise environment through a dynamic threshold mechanism, avoids false triggering or missed detection caused by signal fluctuations of a fixed threshold, and ensures the reliability and accuracy of the candidate peak position.

[0015] In an optional implementation manner, determining the synchronization peak window includes: Use the candidate peak position as the center, and expand the window length range covering the maximum multipath delay forward and backward as the synchronization peak window; the window length range includes the synchronization peaks of all effective multipath components.

[0016] The frame synchronization method for broadband power line communication provided by this application ensures that the synchronization peaks of all effective multipath components are included in the window by covering the multipath delay range, avoids the omission of synchronization peaks caused by multipath dispersion, and improves the synchronization capture ability in a multipath environment.

[0017] In an optional implementation manner, determining the noise evaluation window includes: Select an area that is at a preset distance from the synchronization peak window and has no overlap as the noise evaluation window; the window length of the noise evaluation window is greater than the window length of the synchronization peak window.

[0018] The frame synchronization method for broadband power line communication provided by this application sets a noise evaluation window and a synchronization peak window without overlap and with a larger window length, and selects regions at a preset distance interval. The non-overlapping regions ensure the purity of noise samples, and the larger window length improves the statistical stability of noise energy evaluation, providing a more accurate noise benchmark for signal validity determination.

[0019] In an alternative embodiment, based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window, determining the validity of a candidate peak includes: Extracting the average value of the autocorrelation accumulation values within the noise evaluation window as the average noise energy; Calculating the difference between the autocorrelation accumulation value of each sampling point within the synchronization peak window and the average noise energy to obtain the signal energy; Accumulating and averaging the signal energy to obtain the signal power; Performing a ratio operation on the signal power and the average noise energy to obtain the signal-to-noise ratio; If the signal-to-noise ratio is greater than a preset threshold, it is determined that the candidate peak is valid.

[0020] The frame synchronization method for broadband power line communication provided by this application determines the validity of a candidate peak by calculating the signal-to-noise ratio of the signal power (accumulative average of the difference from the average noise energy) within the synchronization peak window to the noise energy. Quantifying the energy difference between the signal and the noise through the signal-to-noise ratio avoids misjudgment caused by noise fluctuations or false peaks, ensuring that only valid synchronization peaks are selected and improving the accuracy of synchronization peak determination.

[0021] In an alternative embodiment, the method further includes: If the signal-to-noise ratio is less than or equal to the preset threshold, it is determined that the candidate peak is invalid, discard the current candidate peak and re-determine the candidate peak position.

[0022] The frame synchronization method for broadband power line communication provided by this application, through the mechanism of actively discarding invalid peaks, avoids the influence of incorrect synchronization peaks on subsequent processing flows, and improves the fault tolerance of the system and the overall synchronization success rate.

[0023] In an alternative embodiment, determining the target synchronization peak position according to the average value of the peak positions within the synchronization peak window includes: Extracting a preset number of peaks with the largest amplitudes from the autocorrelation accumulation values within the synchronization peak window; Performing an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronization peak position.

[0024] The frame synchronization method for broadband power line communication provided by this application, through the multi-peak position averaging strategy, weakens the random offset caused by multipath or noise of a single peak, reduces the overall deviation of the synchronization position, and improves the synchronization positioning accuracy.

[0025] In summary, the frame synchronization method for broadband power line communication provided by this application symbolizes the received signal through symbol cross-correlation calculation and performs addition and subtraction operations with the local preamble before synchronization, significantly reducing the computational complexity and providing a basis for subsequent real-time processing. On this basis, through autocorrelation accumulation, product operation is performed on the cross-correlation values and window accumulation covering multipath delays is carried out to suppress noise interference and enhance the significance of synchronization peaks. Combining with the dynamic threshold mechanism to adaptively update the threshold value, candidate peak positions are preliminarily screened to avoid misjudgment caused by a fixed threshold. Further, through a dual-window design, the synchronization peak window (covering the multipath delay range) and the noise evaluation window (non-overlapping and with a larger window length) are separated to accurately distinguish the signal and noise energy. Based on signal-to-noise ratio calculation and the mechanism of actively discarding invalid peaks, false peak interference is excluded to ensure the validity of candidate peaks. Finally, through multi-peak position averaging and correction, the single-peak offset error is weakened and the synchronization positioning accuracy is improved. In the solution of this application, low-complexity symbol cross-correlation provides feasibility for real-time processing. Autocorrelation accumulation and dual-window design jointly suppress multipath and noise. Dynamic threshold and signal-to-noise ratio determination construct two-level fault-tolerant screening. Multi-peak averaging realizes the final error correction, significantly improving the synchronization accuracy, anti-interference ability and reliability of the broadband power line communication system in a complex channel environment.

[0026] In a second aspect, this application provides a frame synchronization device for broadband power line communication, and the device includes: A cross-correlation module, configured to perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence; An autocorrelation module, configured to sequentially perform autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence to generate an autocorrelation accumulation value sequence; A candidate peak determination module, configured to determine candidate peak positions based on the absolute values of the autocorrelation accumulation values in the autocorrelation accumulation value sequence; A window definition module, configured to determine a synchronization peak window centered on the candidate peak positions and determine a noise evaluation window in an area non-overlapping with the synchronization peak window; A validity judgment module, configured to judge the validity of the candidate peaks based on the autocorrelation accumulation values within the synchronization peak window and the autocorrelation accumulation values within the noise evaluation window; A frame synchronization module, configured to, if it is determined to be valid, determine the target synchronization peak position according to the average value of the peak positions within the synchronization peak window to complete frame synchronization.

[0027] In a third aspect, this application provides a computer device, including: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to execute the frame synchronization method for broadband power line communication in the first aspect or any corresponding implementation manner thereof.

[0028] Fourthly, the present application provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to cause a computer to execute the frame synchronization method for broadband power line communication according to the first aspect or any corresponding embodiment thereof above.

[0029] Fifthly, the present application provides a computer program product, including computer instructions, and the computer instructions are used to cause a computer to execute the frame synchronization method for broadband power line communication according to the first aspect or any corresponding embodiment thereof above. Description of the Drawings

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is a schematic flowchart of the frame synchronization method for broadband power line communication according to an embodiment of the present application; Figure 2 It is a schematic diagram of the cross-correlation simulation result in the case of single-user with noise in OFDM according to an embodiment of the present application; Figure 3 It is a schematic diagram of the autocorrelation simulation result in the case of single-user with noise in OFDM according to an embodiment of the present application; Figure 4 It is a schematic diagram of the autocorrelation simulation result in the case of 4 users with noise in OFDMA according to an embodiment of the present application; Figure 5 It is a schematic diagram of the autocorrelation accumulation sequence simulation result in the case of 4 users with noise in OFDMA according to an embodiment of the present application; Figure 6 It is a block diagram of the structure of the frame synchronization device for broadband power line communication according to an embodiment of the present application; Figure 7 It is a schematic diagram of the hardware structure of the computer device according to an embodiment of the present application. Detailed Embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0033] First, introduce the terms involved in this application.

[0034] OFDMA (Orthogonal Frequency Division Multiple Access): Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of Orthogonal Frequency Division Multiplexing (OFDM), mainly used in wireless communication systems such as 4G LTE, 5G NR, Wi-Fi 6 (802.11ax), etc.

[0035] BPLC (Broadband Power Line Communication): Broadband Power Line Communication (BPLC) is a communication technology that uses power lines for high-speed data transmission. It belongs to a type of PLC (Power Line Communication), focusing on providing higher data rates (generally referring to communications above 1 Mbps).

[0036] This application relates to a frame synchronization method in broadband power line communication (BPLC), especially applicable to the complex channel environment of Orthogonal Frequency Division Multiple Access (OFDMA) systems. In power line communication, data is transmitted through power lines, and the channel characteristics are complex, with severe multipath effects and noise interference. Traditional frame synchronization methods are usually designed based on Orthogonal Frequency Division Multiplexing (OFDM) systems, and synchronization is achieved by detecting the cross-correlation peak between the received signal and the local synchronization preamble. However, with the introduction of OFDMA technology, multiple users share subcarrier resources in the same time slot, resulting in superposition interference due to multi-user time delay and path differences during signal transmission. Traditional synchronization methods still have limitations.

[0037] First, the multipath effect causes the energy of the synchronization peak to disperse. In an OFDMA system, concurrent transmission by multiple users causes the same signal to reach the receiving end through different paths, forming multipath components after superposition, resulting in the main peak energy of the cross-correlation peak being dispersed into multiple secondary peaks. Cross-correlation verifies the similarity between the received signal and the locally pre-stored SYNC P sequence. However, in an OFDMA system, multiple users share time slots, and signal superposition causes the synchronization peak of the received signal to split into multiple secondary peaks (multipath effect), resulting in a lower peak amplitude. Moreover, power line impulse noise randomly raises the noise floor, further masking the cross-correlation peak amplitude. Traditional cross-correlation peak detection is difficult to effectively detect the synchronization peak, and the synchronization position is prone to deviation.

[0038] Secondly, it is highly sensitive to noise. In the power line channel, the noise spectrum is complex and time-varying. The traditional fixed-threshold detection mechanism cannot adapt to dynamic noise fluctuations, and it is prone to misjudgment or missed judgment due to false peaks caused by noise or attenuation of the main peak amplitude. In addition, the synchronization accuracy is limited by the single-peak selection strategy. Existing technologies directly determine the synchronization point through the single-peak position, without considering the random perturbation of the multi-path components on the peak position, resulting in poor stability of the synchronization result and affecting the reliability of subsequent data demodulation.

[0039] To address the above problems, existing improvement solutions mostly focus on optimizing the cross-correlation algorithm or adjusting the threshold strategy. For example, high-order modulation or adaptive filtering techniques are used. However, such methods often have high computational complexity and are difficult to meet the real-time requirements of power line communication. In addition, some solutions attempt to improve the synchronization accuracy through joint multi-peak detection, but they do not effectively solve the problem of separating noise and multi-path energy, resulting in insufficient robustness of the algorithm.

[0040] Therefore, there is an urgent need for a high-precision frame synchronization method that can balance multi-path resistance and noise interference at low complexity to adapt to the actual requirements of the OFDMA power line communication system.

[0041] The embodiment of the present application provides a frame synchronization method for broadband power line communication. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here. Figure 1 is a flowchart of the frame synchronization method for broadband power line communication according to the embodiment of the present application, as Figure 1 shown, this process includes the following steps: S101. Perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence.

[0042] Specifically, in step S101, the received signal refers to the original electrical signal obtained by the receiving end after being transmitted through the power line channel, which includes a preamble (a specific sequence for synchronization) and a data signal.

[0043] Cross-correlation measures the similarity between two signals after time shift and is mathematically achieved through the accumulation operation of the product of the sampling points of the two signals. In power line carrier communication, synchronization is generally performed through cross-correlation calculation. When the received signal matches the local reference sequence, an obvious peak will appear, and this obvious peak is the correlation peak. Existing cross-correlation calculations require multiplying the corresponding sampling points and then accumulating. When the number of subcarriers is large, the computational complexity is very high, increasing the system's computational load. The symbol cross-correlation calculation used in this application is a cross-correlation method that simplifies the calculation. It only uses the symbols (positive / negative) of the received signal instead of the actual amplitude, maps the amplitude of the received signal to +1 (positive amplitude) or -1 (negative amplitude), simplifies multiplication to addition and subtraction operations, can significantly reduce the computational amount at the receiving end, and improve the synchronization rate.

[0044] The cross-correlation sequence is the sequence output by the symbol cross-correlation calculation. Each value represents the matching degree between the received signal and the local sequence at a specific time shift, and the peak corresponds to the possible synchronization position.

[0045] Specifically, step S101 can perform symbolization processing on the received signal to obtain symbol data that retains the amplitude; perform addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence. The local synchronization preamble sequence is a pre-stored reference sequence, and the number of sampling points of the local synchronization preamble sequence is the same as that of the synchronization preamble sequence in the valid signal. It should be noted that the received signal includes a noise signal and a valid signal. The valid signal includes a synchronization preamble sequence and a data sequence. When synchronization is successful, it means that the synchronization preamble sequence has been detected, that is, the valid signal has been detected, and subsequent demodulation and other operations can be performed. The receiving end needs to synchronize the frame start position of the valid signal to parse the frame boundary. If the clocks are not synchronized, noise may be misjudged as the frame start, resulting in an increase in the frame error rate (FER).

[0046] Specifically, the received signal can be traversed through a sliding window (with a length equal to the length of the synchronization preamble sequence), and the symbolized data within the window is matched with the local synchronization preamble sequence to generate a cross-correlation value sequence that reflects the similarity between the two.

[0047] S102: Perform autocorrelation calculations on the cross-correlation values in the cross-correlation sequence in turn and accumulate them to generate an autocorrelation accumulation value sequence.

[0048] Specifically, in the above step S102, the autocorrelation calculation refers to performing correlation analysis on the cross-correlation sequence itself, that is, calculating the correlation between the current cross-correlation value and the historical cross-correlation value. Accumulation refers to performing a summation operation on the autocorrelation results within a certain window range.

[0049] The specific process of step S102 is as follows: Multiply the current cross-correlation value by the historical cross-correlation value before the preset interval to obtain an autocorrelation result; accumulate the autocorrelation result within a preset window range to obtain an autocorrelation accumulation value sequence; the preset window range covers the maximum number of sampling points corresponding to the multipath delay.

[0050] In OFDMA power line communication, multi-user sharing of time slots leads to the following synchronization difficulties: In OFDMA, different subcarriers are assigned to multiple users. While supporting multi-user concurrent transmission, due to multi-user delays, the corresponding subcarriers will have a time-domain misalignment when merged, resulting in the cross-correlation peak in the synchronization process splitting into multiple secondary peaks, that is, causing the multipath effect; the multipath effect will reduce the size of the peak. At the same time, the power line carrier signal is easily affected by various noises, resulting in the inability to clearly distinguish the noise from the effective signal. Especially in a low signal-to-noise ratio environment, the synchronization failure rate is high. In this application, the autocorrelation operation after cross-correlation can amplify the periodic signal and reduce the impact of noise on the peak. However, due to the multipath effect, simply relying on cross-correlation combined with autocorrelation cannot significantly distinguish the synchronization peak from the noise, resulting in insufficient synchronization peak significance.

[0051] After the autocorrelation operation after cross-correlation in the above step S102, the above problem is solved by autocorrelation accumulation. By sequentially selecting each value in the cross-correlation sequence, performing an autocorrelation operation on it with the historical interval (such as the value before a fixed distance), and accumulating the results within a preset window, a new autocorrelation accumulation value sequence is generated. Thus, the autocorrelation values corresponding to the secondary peaks generated by the multipath effect can be further accumulated, thereby enhancing the synchronization peak significance. Optionally, the preset window range covers the maximum number of sampling points corresponding to the multipath delay, and the maximum number of sampling points of the multipath delay can be set according to the actual communication situation.

[0052] For example, the cross-correlation result can be multiplied by the historical cross-correlation value 1024 sampling points (the length of the SYNCP sequence) before. Subsequently, within the window covering the maximum multipath delay (such as 80 sampling points), the autocorrelation product results are accumulated.

[0053] Due to the periodic repetition of the SYNCP sequence, its cross-correlation value will have a peak again at an interval of 1024 points. Therefore, the product operation amplifies the energy of the effective signal by a square order. The cross-correlation value of the noise has no periodicity at an interval of 1024 points, and the product result approaches zero, and the noise energy is significantly suppressed.

[0054] By accumulating the autocorrelation product results, the multipath components of the same user are superimposed within the window, forming a single concentrated main peak, avoiding energy dispersion; moreover, the random fluctuations of the noise cancel each other out during the accumulation process, further improving the signal-to-noise ratio.

[0055] S103. Determine the candidate peak position based on the absolute value of the autocorrelation cumulative value in the autocorrelation cumulative value sequence.

[0056] Specifically, in step S103, taking the absolute value of the autocorrelation cumulative value is used to eliminate the negative correlation interference. The candidate peak position refers to the sampling point position that may be initially determined as the synchronization peak.

[0057] By traversing the autocorrelation cumulative value sequence, dynamically detect the peak according to the absolute value size. The position where the absolute value first exceeds the preset threshold is recorded as the candidate peak, and continue to search backward until the peak no longer increases, and finally determine the candidate peak position. Specifically, it includes the following processes: Traverse the autocorrelation cumulative value sequence based on the preset initial threshold value; When it is detected that the absolute value of the autocorrelation cumulative value first exceeds the initial threshold value, update the threshold value with the absolute value of the current autocorrelation cumulative value, and record the current position as the candidate peak position; Continue to traverse the autocorrelation cumulative value sequence backward. If it is detected that the absolute value of the autocorrelation cumulative value exceeds the updated threshold value later, update the threshold value with the larger absolute value, and update the candidate peak position to the current detection position; When no larger autocorrelation absolute value is detected within the continuous preset sampling points, stop traversing and obtain the final candidate peak position.

[0058] S104. Determine the synchronization peak window centered on the candidate peak position, and determine the noise evaluation window in the area without overlap with the synchronization peak window.

[0059] Specifically, in step S104, the synchronization peak window is the sampling point range centered on the candidate peak, covering the time delay interval of the potential synchronization peak and the multipath components. The noise evaluation window is the area without overlap with the synchronization peak window, which is used to extract the noise energy samples. According to the candidate peak position, delimit the synchronization peak window (such as extending a certain number of sampling points forward and backward), and at the same time delimit a larger noise evaluation window at a position far from this window to ensure the separation of the signal and noise samples.

[0060] Among them, determining the synchronization peak window is to take the candidate peak position as the center, and extend the window length range covering the maximum multipath time delay forward and backward as the synchronization peak window; the window length range includes the synchronization peaks of all effective multipath components. Determining the noise evaluation window is to select the area with a preset distance and no overlap from the synchronization peak window as the noise evaluation window; the window length of the noise evaluation window is greater than the window length of the synchronization peak window.

[0061] S105. Determine the validity of the candidate peak based on the autocorrelation cumulative value within the synchronization peak window and the autocorrelation cumulative value within the noise evaluation window.

[0062] Specifically, in step S105, by comparing the signal and noise energy differences, determine whether the candidate peak is a true synchronization peak.

[0063] Calculate the signal energy (such as the accumulated mean) of the autocorrelation accumulation value within the synchronous peak window, and compare it with the noise energy of the noise evaluation window. If the signal energy is significantly higher than the noise energy (such as the signal-to-noise ratio exceeding the threshold), then determine that the candidate peak is valid.

[0064] The specific determination of validity includes the following process: Extract the average value of the autocorrelation accumulation value within the noise evaluation window as the average noise energy; Calculate the difference between the autocorrelation accumulation value of each sampling point within the synchronous peak window and the average noise energy to obtain the signal energy; Accumulate and average the signal energy to obtain the signal power; Perform a ratio operation on the signal power and the average noise energy to obtain the signal-to-noise ratio; If the signal-to-noise ratio is greater than the preset threshold, then determine that the candidate peak is valid.

[0065] In addition, if the signal-to-noise ratio is less than or equal to the preset threshold, then determine that the candidate peak is invalid, discard the current candidate peak, and re-determine the candidate peak position.

[0066] S106. If it is determined to be valid, then determine the target synchronous peak position according to the average value of the peak positions within the synchronous peak window to complete frame synchronization.

[0067] Specifically, in step S106, the average value of the peak positions is obtained by averaging the sampling point positions of multiple significant peaks within the synchronous peak window to eliminate the single-peak offset error. Extract multiple peak positions (such as the first three maximum values) within the synchronous peak window, calculate the average value of their sampling point positions as the final target synchronous peak position to complete frame synchronization. The specific process is as follows: Extract the preset number of peaks with the largest amplitude from the autocorrelation accumulation value within the synchronous peak window; perform an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronous peak position.

[0068] In summary, the frame synchronization method for broadband power line communication provided by the embodiments of the present application symbolizes the received signal through symbol cross-correlation calculation and performs addition and subtraction operations with the local preamble before synchronization, significantly reducing the computational complexity and providing a basis for subsequent real-time processing. On this basis, through autocorrelation accumulation, product operation is performed on the cross-correlation values and window accumulation covering multipath delays is carried out to suppress noise interference and enhance the significance of synchronization peaks. Combining with the dynamic threshold mechanism, the threshold value is adaptively updated to preliminarily screen the candidate peak positions and avoid misjudgment caused by a fixed threshold. Further, through the dual-window design, the synchronization peak window (covering the multipath delay range) and the noise evaluation window (non-overlapping and with a larger window length) are separated to accurately distinguish the signal and noise energy. Based on the signal-to-noise ratio calculation and the false peak active discard mechanism, false peak interference is excluded to ensure the validity of candidate peaks. Finally, through multi-peak position average correction, the single-peak offset error is weakened to improve the synchronization positioning accuracy. In the solution of the present application, the low-complexity symbol cross-correlation provides feasibility for real-time processing, the autocorrelation accumulation and the dual-window design jointly suppress multipath and noise, the dynamic threshold and the signal-to-noise ratio determination construct two-level fault-tolerant screening, and the multi-peak averaging realizes the final error correction, significantly improving the synchronization accuracy, anti-interference ability and reliability of the broadband power line communication system in a complex channel environment.

[0069] Exemplarily, a specific example will be used below to illustrate the frame synchronization method for broadband power line communication in the above embodiments.

[0070] This example addresses the frame synchronization problem of the OFDMA system in broadband power line communication (BPLC), and proposes a synchronization method combining symbol cross-correlation, autocorrelation accumulation, dynamic threshold adjustment, noise separation and multi-peak averaging to solve the problem of reduced synchronization accuracy caused by multipath effects and noise interference.

[0071] The frame synchronization of BPLC is achieved by using the periodicity and correlation of the preamble signal. In this example, the preamble symbol is composed of 10.5 SYNCP sequences and 2.5 SYNCM sequences concatenated, and each sequence is 1024 sampling points. The specific steps of the BPLC frame synchronization in this example are as follows.

[0072] Use a sliding window with a length of 1024 to window the input data and perform symbol cross-correlation with the local SYNCP sequence (only take the symbols of the input signal). Through symbol cross-correlation, only take the symbols of the input signal. For example, if the amplitude is positive, take +1, and if the amplitude is negative, take -1. The normal cross-correlation calculation is to multiply the 1024 points in the local SYNCP with the 1024 points corresponding to the sliding window. However, in this example, since only the symbols of the input signal are taken, the cross-correlation calculation in this example only requires addition and subtraction operations. The advantage of only taking symbols is to avoid multiplication operations and save operation time. This step generates a cross-correlation sequence by preliminarily detecting the positions in the received signal that match the SYNCP sequence to achieve preliminary synchronization peak detection.

[0073] In the prior art, the local sequence is cross-correlated with the received signal, and then the cross-correlation peak is judged by a threshold. However, the cross-correlation peak will change in different noise environments and is sometimes not obvious. Therefore, in this embodiment, the obtained cross-correlation result is stored in a Buffer (cache), and after obtaining a new cross-correlation value each time, it is autocorrelated with the cross-correlation values before its 1024th point to obtain an autocorrelation result. That is, an autocorrelation calculation with an interval of 1024 points is performed on the cross-correlation sequence (the current sampling point is multiplied by the historical value before the 1024th point). Based on the cross-correlation value, autocorrelation is further performed, that is, two cross-correlation values at a preset interval are multiplied, so that a more obvious autocorrelation peak can be obtained.

[0074] It should be noted that the above preset interval is equal to the interval between SYNCP symbols. For example, the preamble symbol consists of 10.5 SYNCP sequences, and each SYNCP sequence occupies 1024 sampling points. The preset interval of 1024 is exactly the same as the length of the SYNCP sequence, ensuring that the autocorrelation operation accurately matches the periodic characteristics.

[0075] The essence of performing autocorrelation operation on the cross-correlation value according to the preset interval is to perform autocorrelation on the sampling points corresponding to adjacent SYNCP symbols, maximize the main peak energy, so that a more obvious autocorrelation peak than the cross-correlation peak can be obtained (that is, the multiplication of two cross-correlation peak values and peak values is realized).

[0076] Due to the multipath effect, the autocorrelation peak is still easily affected by the multipath effect and noise, resulting in its peak not being obvious. In this embodiment, the obtained autocorrelation result is stored in a Buffer, and after obtaining a new autocorrelation result each time, it is accumulated with the autocorrelation values within a certain window range in front of it to obtain an autocorrelation accumulation value sequence. By accumulating the autocorrelation values within a certain window range, the noise can be further suppressed and the accuracy of the synchronization peak can be improved. The certain window range can be set according to the size of the time delay, specifically set according to the time delay situation in actual communication. For example, if the maximum time delay is 100 sampling points, then the window length of this window is 100 sampling points.

[0077] Noise can be effectively suppressed through cross-correlation + autocorrelation operations. For specific reference, see Figure 2 and Figure 3 , Figure 2 is the cross-correlation simulation result diagram in the case of OFDM (i.e., single user) with noise (-10db), Figure 3 is the autocorrelation simulation result diagram in the case of OFDM (i.e., single user) with noise (-10db). It can be seen that cross-correlation + autocorrelation can effectively suppress noise in the single-user case.

[0078] Accumulating the autocorrelation within a certain window range can better suppress the interference of noise and multipath effects. For specific reference, please refer to Figure 4 and Figure 5 . Figure 4 This is the autocorrelation simulation result graph in the case of OFDMA (4 users) with noise (-10 dB). As can be seen from Figure 4 , the superposition of noise and multipath effects makes the autocorrelation result have many spikes, and the position of the synchronization peak is not obvious. That is, at this time, the method of cross-correlation + autocorrelation will still have a lot of interference from noise + multipath effects, and the position of the synchronization peak cannot be accurately judged. Figure 5 This is the simulation result graph of the autocorrelation accumulation sequence in the case of OFDMA (4 users) with noise (-10 dB). It can be seen that, compared with Figure 4 , the curve of the autocorrelation accumulation sequence is smoother, the position of the synchronization peak is obvious, thus significantly improving the accuracy of judgment.

[0079] Set an initial threshold value. After the initial threshold is triggered, update the threshold value with the absolute value of the current maximum autocorrelation accumulation value, and continue to search backward until there is no larger value within a certain number of consecutive sampling points. This certain number can be 20 - 50 sampling points, and the initial threshold value can be set according to the actual communication situation.

[0080] Specifically, when the absolute value of the autocorrelation accumulation value is greater than the set initial threshold value, it indicates that the position where the detected data has a large correlation with the local sequence has been found. However, there is an ascending process for the correlation peak. Therefore, it is necessary to continue to find the position where the correlation peak is the largest. The method is to update the threshold value with this value every time a larger autocorrelation accumulation value is obtained, and continue to search backward until it no longer increases, and record this position and the current absolute value of the autocorrelation accumulation. Determine the candidate synchronization peak position through this method.

[0081] According to the obtained candidate synchronization peak position, set a fixed window length A and store the synchronized autocorrelation accumulation value. For example, take the first 20 points and the last 20 points of the candidate peak position as window A. The purpose here is to further determine whether the signals within the maximum peak interval range (window A) can meet the preset conditions for OFDMA signals where the maximum peak position may not be an accurate synchronization peak.

[0082] The window length of window A here is set according to the multipath delay. The window length of window A needs to cover the maximum delay of the multipath signal to ensure that the synchronization peak including all effective multipath components is included. For example, if the multipath delay is 4 μs and the sampling rate is 20 MHz (sampling interval 50 ns), then the delay corresponds to 80 sampling points, and the corresponding window length can be 80 sampling points on both sides of the maximum peak position.

[0083] After selecting the window length A, another fixed window length B (B < 800) is set. The synchronization peaks of BPLC are theoretically fixed with a distance of 1024. Select the part without synchronization peaks in the middle to calculate the average noise energy (the average value of the autocorrelation value accumulation sequence). Among them, the window length of window A is different from that of window B. Generally, window A is smaller than window B.

[0084] Subtract the average value of the noise energy in window B from the autocorrelation accumulation value of the sampling points in window A to obtain the signal energy corresponding to window A. Accumulate and average the signal energy to obtain the signal power. Calculate the signal-to-noise ratio SNR = (average of peak interval - average noise) / average noise. Determine whether the signal in window A is a valid signal according to the comparison between the signal-to-noise ratio and the preset threshold.

[0085] The autocorrelation accumulation value of each sampling point in window A minus the average value of the autocorrelation accumulation value in window B = the signal energy corresponding to the peak interval. The signal-to-noise ratio SNR = the accumulated average of the signal energy corresponding to the peak interval / the average value of the autocorrelation accumulation value in window B.

[0086] Compare the signal-to-noise ratio SNR with the threshold to determine whether the synchronization peak in the peak interval is a valid peak.

[0087] The signal within the peak interval (i.e., within window A) is very likely to be a valid signal. By subtracting the noise energy, theoretically, the autocorrelation accumulation value of the noise-free valid signal is obtained, and then the ratio to the noise is calculated, so as to determine whether the synchronization peak within this interval is a valid peak. This can exclude noise interference, verify the effectiveness of the synchronization peak, and filter out low-quality candidate peaks through the SNR threshold. Considering that in the absence of multipath effects, whether the synchronization peak is valid is determined according to the signal-to-noise ratio of the maximum peak and the signal-to-noise ratio threshold, and the signal-to-noise ratio threshold is set relatively high. In the presence of multipath effects, the signal-to-noise ratio of the maximum peak will decrease. At this time, it is not accurate to judge whether the synchronization peak is valid through the maximum peak. In this application, a relatively low signal-to-noise ratio threshold can be set, and the signal-to-noise ratio within window A is used to judge whether the synchronization peak within the peak interval is a valid peak, thus considering the influence of multipath effects and noise on the valid peak and improving the accuracy of synchronization peak judgment.

[0088] In OFDMA, due to the existence of multipath effects, the position of the maximum peak does not reflect the true position of the synchronization peak. Instead, the results of multiple peak positions and SNR need to be comprehensively considered. Therefore, after determining the effectiveness of the candidate synchronization peak in window A, the average value of the sampling points greater than the initial peak threshold within the peak interval (window A) can be taken, or the average value of the first three largest autocorrelation peaks within the peak interval can be taken as the synchronization peak position; the weighted average value of multiple peaks can also be taken. Here, the average value refers to the average value of the sampling points corresponding to the peak value. For example, if the sampling points corresponding to the three peak values are X1, X2, and X3 respectively, then the synchronization peak position is (X1 + X2 + X3) / 3.

[0089] The above process uses a progressive design of symbol cross-correlation noise reduction, autocorrelation enhancement, dynamic threshold screening, window A / B signal and noise separation, SNR verification, and multi-peak correction, which surpasses traditional methods in terms of computational efficiency, anti-interference ability, and synchronization accuracy, providing a highly reliable and low-complexity frame synchronization solution for BPLC and OFDMA systems.

[0090] In this embodiment, a frame synchronization device for broadband power line communication is also provided. This device is used to implement the above embodiments and preferred implementation manners, and those that have been described will not be elaborated again. As used hereinafter, the term "module" can be a combination of software and / or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0091] This embodiment provides a frame synchronization device for broadband power line communication, as Figure 6 shown, including: A cross-correlation module 601, configured to perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence; An autocorrelation module 602, configured to sequentially perform autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence to generate an autocorrelation accumulation value sequence; A candidate peak determination module 603, configured to determine the candidate peak position based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence; A window definition module 604, configured to determine a synchronization peak window centered on the candidate peak position and determine a noise evaluation window in an area without overlap with the synchronization peak window; A validity judgment module 605, configured to determine the validity of the candidate peak based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window; A frame synchronization module 606, configured to, if determined to be valid, determine the target synchronization peak position based on the average value of the peak positions within the synchronization peak window to complete frame synchronization.

[0092] In an alternative embodiment, the cross-correlation module 601 is specifically configured to: Perform symbolization processing on the received signal to obtain symbol data retaining the amplitude; Perform addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence.

[0093] In an alternative embodiment, the autocorrelation module 602 is specifically configured to: Perform a multiplication operation on the current cross-correlation value and the historical cross-correlation value before a preset interval to obtain an autocorrelation result; Accumulate the autocorrelation results within the preset window range to obtain an autocorrelation accumulation value sequence; the preset window range covers the maximum number of sampling points corresponding to the multipath delay.

[0094] In an alternative embodiment, the candidate peak determination module 603 is specifically configured to: Traverse the autocorrelation accumulation value sequence based on a preset initial threshold; When it is detected that the absolute value of the autocorrelation accumulation value first exceeds the initial threshold, update the threshold with the absolute value of the current autocorrelation accumulation value, and record the current position as the candidate peak position; Continue to traverse the autocorrelation accumulation value sequence backward. If it is subsequently detected that the absolute value of the autocorrelation accumulation value exceeds the updated threshold, update the threshold with a larger absolute value, and update the candidate peak position to the current detection position; When no larger absolute value of the autocorrelation accumulation is detected within a continuous preset number of sampling points, stop traversing and obtain the final candidate peak position.

[0095] In an alternative embodiment, the window definition module 604 is specifically configured to: Centering on the candidate peak position, expand the window length range covering the maximum multipath delay forward and backward as the synchronization peak window; the window length range includes the synchronization peaks of all valid multipath components.

[0096] In an alternative embodiment, the window definition module 604 is further configured to: Select an area that is at a preset distance from the synchronization peak window and has no overlap as the noise evaluation window; the window length of the noise evaluation window is greater than the window length of the synchronization peak window.

[0097] In an alternative embodiment, the validity judgment module 605 is specifically configured to: Extract the average value of the autocorrelation accumulation values within the noise evaluation window as the noise average energy; Calculate the difference between the autocorrelation accumulation value of each sampling point within the synchronization peak window and the noise average energy to obtain the signal energy; Accumulate and average the signal energy to obtain the signal power; Perform a ratio operation on the signal power and the noise average energy to obtain the signal-to-noise ratio; If the signal-to-noise ratio is greater than a preset threshold, determine that the candidate peak is valid.

[0098] In an alternative embodiment, the validity judgment module 605 is further configured to: If the signal-to-noise ratio is less than or equal to the preset threshold, determine that the candidate peak is invalid, discard the current candidate peak, and re-determine the candidate peak position.

[0099] In an alternative embodiment, the frame synchronization module 606 is specifically configured to: Extract a preset number of peaks with the largest amplitudes from the autocorrelation accumulated values within the synchronization peak window; Perform an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronization peak position.

[0100] The further functional descriptions of the above-mentioned various modules and units are the same as those in the corresponding method embodiments described above, and will not be elaborated here.

[0101] The frame synchronization device for broadband power line communication in this embodiment is presented in the form of functional units. Here, the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0102] This application embodiment also provides a computer device having the above Figure 6 shown frame synchronization device for broadband power line communication.

[0103] Please refer to Figure 7 , Figure 7 which is a schematic structural diagram of a computer device provided by an optional embodiment of this application. As Figure 7 shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including a high-speed interface and a low-speed interface. Each component communicates with each other using different buses and can be installed on a common motherboard or installed in other ways as needed. The processor can process instructions executed within the computer device, including instructions stored in the memory or on the memory to display graphical information of the GUI on an external input / output device (such as a display device coupled to the interface). In some optional implementation manners, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (such as an array of servers, a set of blade servers, or a multi-processor system). Figure 7 In

[0104] Processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, processor 10 can further include a hardware chip. The above hardware chip can be an application specific integrated circuit, a programmable logic device, or a combination thereof. The above programmable logic device can be a complex programmable logic device, a field programmable gate array, a general array logic, or any combination thereof.

[0105] Among them, the memory 20 stores instructions executable by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiments.

[0106] The memory 20 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 may optionally include a memory remotely provided with respect to the processor 10, and these remote memories may be connected to the computer device through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0107] The memory 20 may include a volatile memory, for example, a random access memory; the memory may also include a non-volatile memory, for example, a flash memory, a hard disk, or a solid-state drive; the memory 20 may also include a combination of the above types of memories.

[0108] The computer device further includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30, and the output device 40 may be connected through a bus or other means. Figure 7 Taking the connection through the bus as an example.

[0109] The input device 30 can receive input digital or character information, and generate key signal inputs related to the user settings and function control of the computer device, such as a touch screen, a keypad, a mouse, a trackpad, a touchpad, a pointing stick, one or more mouse buttons, a trackball, a joystick, etc. The output device 40 may include a display device, an auxiliary lighting device (for example, an LED), and a tactile feedback device (for example, a vibration motor), etc. The above display device includes but is not limited to a liquid crystal display, a light-emitting diode, a display, and a plasma display. In some alternative embodiments, the display device may be a touch screen.

[0110] Embodiments of the present application also provide a computer-readable storage medium. The methods according to the embodiments of the present application can be implemented in hardware, firmware, or be implemented as computer code that can be recorded on a storage medium, or be implemented as computer code that is originally stored in a remote storage medium or a non-transitory machine-readable storage medium and downloaded through a network and will be stored in a local storage medium. Thus, the methods described herein can be stored as such software processes on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by the computer, the processor, or the hardware, the methods shown in the above embodiments are implemented.

[0111] A part of the present application can be applied as a computer program product, for example, computer program instructions. When executed by a computer, through the operation of the computer, the methods and / or technical solutions according to the present application can be invoked or provided. Those skilled in the art should be able to understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Herein, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible by the computer.

[0112] Although the embodiments of the present application are described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present application. Such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A frame synchronization method for broadband power line communication, characterized in that, The method includes: Performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence; Successively performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence to generate an autocorrelation accumulation value sequence; Based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence, determining the candidate peak position; Determining a synchronization peak window centered on the candidate peak position, and determining a noise evaluation window in an area without overlap with the synchronization peak window; Based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window, determining the validity of the candidate peak; If it is determined to be valid, determining the target synchronization peak position according to the average value of the peak positions within the synchronization peak window to complete frame synchronization.

2. The method according to claim 1, wherein The performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence includes: Performing symbolization processing on the received signal to obtain symbol data retaining the amplitude; Performing addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence.

3. The method according to claim 2, wherein The successively performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence to generate an autocorrelation accumulation value sequence includes: Performing a product operation on the current cross-correlation value and the historical cross-correlation value before a preset interval to obtain an autocorrelation result; Accumulating the autocorrelation result within a preset window range to obtain an autocorrelation accumulation value sequence; the preset window range covers the maximum number of sampling points corresponding to the multipath delay.

4. The method according to claim 1, wherein The based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence, determining the candidate peak position includes: Based on a preset initial threshold, traversing the autocorrelation accumulation value sequence; When it is detected that the absolute value of the autocorrelation accumulation value first exceeds the initial threshold, updating the threshold with the absolute value of the current autocorrelation accumulation value, and recording the current position as the candidate peak position; Continuing to traverse the autocorrelation accumulation value sequence backward, if it is detected later that the absolute value of the autocorrelation accumulation value exceeds the updated threshold, updating the threshold with a larger absolute value, and updating the candidate peak position to the current detection position; When no larger absolute value of the autocorrelation accumulation is detected within a continuous preset number of sampling points, stop traversing and obtain the final candidate peak position.

5. The method according to claim 1, characterized in that, The determining the synchronization peak window includes: Centering on the candidate peak position, expanding the window length range covering the maximum multipath delay forward and backward as the synchronization peak window; the window length range contains the synchronization peaks of all valid multipath components.

6. The method according to claim 5, characterized in that The determining the noise evaluation window includes: Selecting an area at a preset distance from and without overlap with the synchronization peak window as the noise evaluation window; the window length of the noise evaluation window is greater than the window length of the synchronization peak window.

7. The method according to claim 1, characterized in that, The based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window, determining the validity of the candidate peak includes: Extracting the average value of the autocorrelation accumulation values within the noise evaluation window as the noise average energy; Calculating the difference between the autocorrelation accumulation value of each sampling point within the synchronization peak window and the noise average energy to obtain the signal energy; Accumulating and averaging the signal energy to obtain the signal power; Performing a ratio operation on the signal power and the noise average energy to obtain the signal-to-noise ratio; If the signal-to-noise ratio is greater than a preset threshold, it is determined that the candidate peak is valid.

8. The method according to claim 1, wherein The method further includes: If the signal-to-noise ratio is less than or equal to the preset threshold, it is determined that the candidate peak is invalid, the current candidate peak is discarded, and the candidate peak position is re-determined.

9. The method according to claim 1, characterized in that, The determining the target synchronization peak position according to the average value of the peak positions in the synchronization peak window includes: Extracting a preset number of peaks with the largest amplitudes in the autocorrelation accumulation values within the synchronization peak window; Performing an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronization peak position.

10. A frame synchronization device for broadband power line communication, characterized in that, The device includes: A cross-correlation module for performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence; An autocorrelation module for sequentially performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence to generate an autocorrelation accumulation value sequence; A candidate peak determination module for determining the candidate peak position based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence; A window definition module for determining a synchronization peak window centered on the candidate peak position and determining a noise evaluation window in an area without overlap with the synchronization peak window; A validity judgment module for judging the validity of the candidate peak based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window; A frame synchronization module for, if it is determined to be valid, determining the target synchronization peak position according to the average value of the peak positions in the synchronization peak window to complete frame synchronization.

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