A Frame Synchronization Method and Device for Broadband Power Line Communication

Abstract

The present application relates to the technical field of power line communication, and discloses a frame synchronization method and device for broadband power line communication. The method includes: obtaining a cross-correlation result sequence by performing symbolized cross-correlation operation on a received signal; performing secondary autocorrelation analysis and accumulation processing on the cross-correlation values in the sequence to generate an autocorrelation accumulation value sequence; screening candidate peak positions according to the absolute values of the autocorrelation accumulation values; defining a synchronization peak analysis window around the candidate peak positions, and setting a noise reference window in a region far from the window; verifying the effectiveness of the candidate peaks based on the difference in autocorrelation accumulation values between the synchronization peak window and the noise reference window; if the verification is effective, determining the final synchronization position by calculating the mean value of multiple peak positions within the synchronization peak window. This method solves the problem of inaccurate synchronization peak positioning in the existing methods under multipath effects and noise interference through an autocorrelation accumulation and noise separation mechanism, and improves the reliability of frame synchronization.

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 the 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. The traditional method relies 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, so as 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:

[0006] Performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence;

[0007] Performing autocorrelation calculation and accumulation on the cross-correlation values in the cross-correlation sequence in turn to generate an autocorrelation accumulation value sequence;

[0008] Based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence, determining the candidate peak position;

[0009] Determining a synchronization peak window centered on the candidate peak position, and determining a noise evaluation window in the area without overlap with the synchronization peak window;

[0010] Based on the autocorrelation accumulation value in the synchronization peak window and the autocorrelation accumulation value in the noise evaluation window, determining the validity of the candidate peak;

[0011] If it is determined to be valid, then determining the target synchronization peak position according to the average value of the peak positions in the synchronization peak window to complete frame synchronization.

[0012] 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, autocorrelation calculation is performed on the cross-correlation values and accumulated to generate an autocorrelation accumulation value sequence. The effective signal characteristics are amplified by autocorrelation operation, and the noise fluctuation is suppressed by combining the accumulation operation, enhancing the significance of the synchronization peak. The candidate peak position is dynamically determined by the absolute value, avoiding the interference of noise negative correlation values and improving the accuracy of candidate peak detection. The synchronization peak window and the noise evaluation window are divided centered on the candidate peak to separate the signal energy and noise samples, providing a reliable basis for effectiveness determination. The effectiveness of the candidate peak is determined 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, the target synchronization peak is determined by averaging 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.

[0013] In an alternative embodiment, performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence includes:

[0014] Performing symbolization processing on the received signal to obtain symbol data that retains the amplitude;

[0015] Performing addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence.

[0016] 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 amplitude symbols) 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 feature information to ensure the real-time performance and hardware implementation efficiency of synchronization peak detection.

[0017] 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.

[0018] The frame synchronization method for broadband power line communication provided by this application ensures the matching and integrity of 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 cross-correlation results.

[0019] 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:

[0020] Multiply the current cross-correlation value by the historical cross-correlation value before a preset interval to obtain an autocorrelation result;

[0021] 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.

[0022] The frame synchronization method for broadband power line communication provided by this application amplifies the autocorrelation of the effective signal through multiplication operation, combines window accumulation to suppress the random interference of multipath delay and noise, makes the synchronization peak energy concentrated and significant, and improves the accuracy of synchronization peak detection.

[0023] In an alternative embodiment, determining the candidate peak position based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence includes:

[0024] Traverse the autocorrelation accumulation value sequence based on a preset initial threshold;

[0025] 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;

[0026] 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, update the threshold with a larger absolute value, and update the candidate peak position to the current detection position;

[0027] 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.

[0028] 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.

[0029] In an alternative embodiment, determining the synchronization peak window includes:

[0030] Taking the candidate peak position as the center, 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.

[0031] 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 missing synchronization peaks caused by multipath dispersion, and improves the synchronization capture ability in a multipath environment.

[0032] In an alternative embodiment, determining the noise evaluation window includes:

[0033] Select a region 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 that of the synchronization peak window.

[0034] The frame synchronization method for broadband power line communication provided by this application sets the noise evaluation window to have no overlap with the synchronization peak window and a larger window length, and selects a region at a preset distance. By ensuring no overlap, the purity of the noise samples is guaranteed, and the larger window length improves the statistical stability of the noise energy evaluation, providing a more accurate noise benchmark for signal validity determination.

[0035] In an optional implementation, based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window, determine the validity of the candidate peak, including:

[0036] Extract the average value of the autocorrelation accumulation values within the noise evaluation window as the average noise energy;

[0037] Calculate 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;

[0038] Accumulate and average the signal energy to obtain the signal power;

[0039] Perform a ratio operation on the signal power and the average noise energy to obtain the signal-to-noise ratio;

[0040] If the signal-to-noise ratio is greater than the preset threshold, determine that the candidate peak is valid.

[0041] The frame synchronization method for broadband power line communication provided by this application determines the validity of the candidate peak by calculating the signal-to-noise ratio of the signal power (accumulation average of the difference from the average noise energy) within the synchronization peak window to the noise energy. By quantifying the energy difference between the signal and the noise through the signal-to-noise ratio, it 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.

[0042] In an optional implementation, the method further includes:

[0043] 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.

[0044] The frame synchronization method for broadband power line communication provided by this application, through the active discard mechanism for invalid peaks, avoids the influence of incorrect synchronization peaks on the subsequent processing flow, and improves the fault tolerance of the system and the overall synchronization success rate.

[0045] In an optional implementation, determine the target synchronization peak position according to the average value of the peak positions within the synchronization peak window, including:

[0046] Extract a preset number of peaks with the largest amplitudes from the autocorrelation accumulated values within the synchronous peak window;

[0047] Perform an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronous peak position.

[0048] The frame synchronization method for broadband power line communication provided by this application weakens the random offset caused by multipath or noise of a single peak through a multi-peak position averaging strategy, reduces the overall deviation of the synchronization position, and improves the synchronization positioning accuracy.

[0049] 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 synchronization preamble, significantly reducing the computational complexity and providing a basis for subsequent real-time processing; on this basis, through autocorrelation accumulation, product operations are performed on the cross-correlation values and window accumulation covering the multipath delay is carried out to suppress noise interference and enhance the significance of the synchronous peak; combined 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 a dual-window design, the synchronous 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 discarding mechanism, false peak interference is excluded to ensure the effectiveness of the candidate peaks; finally, the single-peak offset error is corrected through multi-peak position averaging to improve the synchronization positioning accuracy. In the solution of this application, the low-complexity symbol cross-correlation provides feasibility for real-time processing, the autocorrelation accumulation and dual-window design jointly suppress multipath and noise, the dynamic threshold and signal-to-noise ratio determination construct two-level fault-tolerant screening, and 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.

[0050] In a second aspect, this application provides a frame synchronization device for broadband power line communication, and the device includes:

[0051] A cross-correlation module, configured to perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence;

[0052] 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 accumulated value sequence;

[0053] A candidate peak determination module, configured to determine candidate peak positions based on the absolute values of the autocorrelation accumulated values in the autocorrelation accumulated value sequence;

[0054] A window definition module, configured to determine a synchronous peak window centered on the candidate peak positions and determine a noise evaluation window in an area non-overlapping with the synchronous peak window;

[0055] A validity determination module, configured to determine the validity of candidate peaks based on the autocorrelation accumulation value within the synchronization peak window and the autocorrelation accumulation value within the noise evaluation window;

[0056] 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, so as to complete frame synchronization.

[0057] In a third aspect, the present 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 according to the first aspect or any corresponding embodiment thereof.

[0058] In a fourth aspect, 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.

[0059] In a fifth aspect, 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. Description of the Drawings

[0060] 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 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, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 is a schematic flowchart of the frame synchronization method for broadband power line communication according to an embodiment of the present application;

[0062] Figure 2 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;

[0063] Figure 3 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;

[0064] Figure 4 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;

[0065] Figure 5Schematic diagram of the autocorrelation accumulation sequence simulation results for 4 users with noise in the OFDMA case according to an embodiment of the present application;

[0066] Figure 6 Block diagram of the frame synchronization device for broadband power line communication according to an embodiment of the present application;

[0067] Figure 7 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present application. Detailed implementation manners

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0069] First, the terms related to the present application are introduced.

[0070] 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.

[0071] 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).

[0072] The present application relates to a frame synchronization method in broadband power line communication (BPLC), which is particularly applicable to the complex channel environment of an Orthogonal Frequency Division Multiple Access (OFDMA) system. 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 achieve synchronization through the cross-correlation peak detection 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 in the signal transmission process due to multi-user time delays and path differences. The traditional synchronization method still has limitations.

[0073] First, the multipath effect causes the energy of the synchronization peak to disperse. In an OFDMA system, concurrent transmissions of multiple users cause the same signal to reach the receiving end through different paths, and after superposition, multipath components are formed, 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 SYNCP sequence. However, in an OFDMA system, multiple users share time slots, and the 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.

[0074] Second, it is highly sensitive to noise. The noise spectrum in the power line channel is complex and time-varying. The traditional fixed threshold detection mechanism cannot adapt to dynamic noise fluctuations, and false peaks or attenuation of the main peak amplitude caused by noise easily lead to misjudgment or missed detection. 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 multipath components on the peak position, resulting in poor stability of the synchronization result and affecting the reliability of subsequent data demodulation.

[0075] To address the above problems, existing improvement schemes mostly focus on optimizing the cross-correlation algorithm or adjusting the threshold strategy. For example, high-order modulation or adaptive filtering techniques are adopted, but such methods often have high computational complexity and are difficult to meet the real-time requirements of power line communication. In addition, some schemes attempt to improve the synchronization accuracy through joint detection of multiple peaks, but they do not effectively solve the problem of separating noise and multipath energy, resulting in insufficient robustness of the algorithm.

[0076] Therefore, there is an urgent need for a high-precision frame synchronization method that can balance anti-multipath and anti-noise interference at low complexity to adapt to the actual requirements of the OFDMA power line communication system.

[0077] An 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 herein can be executed in a different order. Figure 1 is a flowchart of the frame synchronization method for broadband power line communication according to an embodiment of the present application, as Figure 1 shown, this process includes the following steps:

[0078] S101. Perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence.

[0079] 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.

[0080] Cross-correlation measures the similarity of two signals after time shift and is mathematically achieved by the cumulative 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. The existing cross-correlation calculation needs to multiply the corresponding sampling points and then accumulate them. When the number of subcarriers is large, the computational amount is very large, 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 (+ / −) 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.

[0081] 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.

[0082] In step S101, the received signal can be symbolized to obtain symbol data that retains the amplitude; the symbol data is subjected to addition and subtraction operations with 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).

[0083] 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 reflecting the similarity between the two.

[0084] S102. Perform autocorrelation calculations and accumulations on the cross-correlation values in the cross-correlation sequence in turn to generate an autocorrelation accumulation value sequence.

[0085] 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.

[0086] The specific process of step S102 is as follows: 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 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.

[0087] In OFDMA power line communication, multi-user sharing of time slots leads to the following synchronization difficulties: in OFDMA, different subcarriers are allocated to multiple users. While supporting multi-user concurrent transmission, due to multi-user time delays, the corresponding subcarriers will have a time-domain misalignment when merged, resulting in the splitting of the cross-correlation peak in the synchronization process 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 between the noise and 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, relying solely on cross-correlation combined with autocorrelation cannot significantly distinguish the synchronization peak from the noise, resulting in insufficient significance of the synchronization peak.

[0088] 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 significance of the synchronization peak. 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.

[0089] For example, the cross-correlation result can be multiplied by the historical cross-correlation value 1024 sampling points (SYNCP sequence length) before. Subsequently, within the window covering the maximum multipath delay (such as 80 sampling points), the autocorrelation product result is accumulated.

[0090] 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 multiplication operation amplifies the energy of the effective signal by a square level. 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.

[0091] By accumulating the autocorrelation product results, the multipath components of the same user are superimposed within the window to form a single concentrated main peak, avoiding energy dispersion; moreover, the random fluctuations of the noise cancel each other out during the accumulation process, and the signal-to-noise ratio is further improved.

[0092] S103. Determine the candidate peak position based on the absolute value of the autocorrelation accumulation value in the autocorrelation accumulation value sequence.

[0093] Specifically, in step S103, taking the absolute value of the autocorrelation accumulation value is used to eliminate the negative correlation interference. The candidate peak position refers to the sampling point position that is preliminarily determined to be possibly a synchronization peak.

[0094] By traversing the autocorrelation accumulation 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:

[0095] Based on the preset initial threshold value, traverse the autocorrelation accumulation value sequence;

[0096] 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;

[0097] Continue to traverse the autocorrelation accumulation value sequence backward. If it is detected that the absolute value of the autocorrelation accumulation value exceeds the updated threshold value later, update the threshold value with a larger absolute value, and update the candidate peak position to the current detection position;

[0098] When no larger autocorrelation absolute value is detected within the continuous preset sampling points, stop traversing and obtain the final candidate peak position.

[0099] 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.

[0100] 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.

[0101] Among them, determining the synchronization peak window is to take the candidate peak position as the center, and extend forward and backward to cover the window length range of the maximum multipath time delay 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 interval and no 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.

[0102] S105. 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.

[0103] Specifically, in step S105, by comparing the signal and noise energy differences, it is determined whether the candidate peak is a true synchronization peak.

[0104] Calculate the signal energy (such as the cumulative mean) of the autocorrelation cumulative values within the synchronization 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), the candidate peak is determined to be valid.

[0105] The specific judgment of validity includes the following process:

[0106] Extract the average value of the autocorrelation cumulative values within the noise evaluation window as the average noise energy;

[0107] Calculate the difference between the autocorrelation cumulative value of each sampling point within the synchronization peak window and the average noise energy to obtain the signal energy;

[0108] Accumulate and average the signal energy to obtain the signal power;

[0109] Perform a ratio operation on the signal power and the average noise energy to obtain the signal-to-noise ratio;

[0110] If the signal-to-noise ratio is greater than the preset threshold, the candidate peak is determined to be valid.

[0111] In addition, if the signal-to-noise ratio is less than or equal to the preset threshold, the candidate peak is determined to be invalid, discard the current candidate peak and re-determine the candidate peak position.

[0112] S106. 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.

[0113] 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 synchronization peak window to eliminate the single-peak offset error. Extract multiple peak positions (such as the first three maximum values) within the synchronization peak window, calculate the average value of their sampling point positions as the final target synchronization peak position to complete frame synchronization. The specific process is as follows: Extract the preset number of peaks with the largest amplitude in the autocorrelation cumulative 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.

[0114] In summary, the frame synchronization method for broadband power line communication provided in the embodiment of the present application symbolizes the received signal through symbol cross-correlation calculation and performs addition and subtraction operations with the local synchronization preamble code, which significantly reduces the computational complexity and provides a basis for subsequent real-time processing; on this basis, the cross-correlation value is multiplied by autocorrelation accumulation and the window accumulation covering multipath delay is performed to suppress noise interference and enhance the significance of the synchronization peak; the threshold value is adaptively updated in combination with the dynamic threshold mechanism to preliminarily screen the candidate peak position to avoid misjudgment caused by fixed threshold; further, the synchronization peak window (covering the multipath delay range) and the noise evaluation window (no overlap and larger window length) are separated through a dual-window design to accurately distinguish between signal and noise energy; based on the signal-to-noise ratio calculation and the invalid peak active discarding mechanism, false peak interference is eliminated to ensure the validity of the candidate peak; finally, the single peak offset error is weakened through multi-peak position averaging correction to improve the synchronization positioning accuracy. 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 judgment construct two-level fault-tolerant screening, and multi-peak averaging realizes final error correction, which significantly improves the synchronization accuracy, anti-interference ability and reliability of broadband power line communication systems in complex channel environments.

[0115] For example, a specific example will be used below to illustrate the frame synchronization method for broadband power line communication according to the above embodiment.

[0116] This example addresses the frame synchronization issue in OFDMA systems in power line communication (BPLC). A synchronization method combining symbol cross-correlation, autocorrelation accumulation, dynamic threshold adjustment, noise separation, and multi-peak averaging is proposed to address the degradation of synchronization accuracy caused by multipath and noise interference.

[0117] BPLC frame synchronization utilizes the periodicity and correlation of the preamble signal. In this example, the preamble symbol consists of 10.5 SYNCP sequences and 2.5 SYNCM sequences, each consisting of 1024 sampling points. The specific steps for BPLC frame synchronization in this example are as follows.

[0118] A sliding window of 1024 is used to select the input data and perform symbol cross-correlation with the local SYNCP sequence (taking only the sign of the input signal). Through symbol cross-correlation, only the sign of the input signal is taken. For example, if the amplitude is positive, +1 is taken, and if the amplitude is negative, -1 is taken. A normal cross-correlation calculation multiplies the 1024 points in the local SYNCP by the 1024 points corresponding to the sliding window. However, in this example, since only the sign of the input signal is taken, the cross-correlation calculation in this example only requires addition and subtraction operations. The advantage of taking only the sign is that multiplication operations are avoided, saving calculation time. This step generates a cross-correlation sequence by preliminarily detecting the position in the received signal that matches the SYNCP sequence, thereby achieving preliminary synchronization peak detection.

[0119] 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 each time a new cross-correlation value is obtained, it is autocorrelated with the cross-correlation values before its 1024th point to obtain the autocorrelation result. That is, autocorrelation calculation is performed on the cross-correlation sequence at an interval of 1024 points (the current sampling point is multiplied by the historical value 1024 points before). 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.

[0120] 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 strictly consistent with the length of the SYNCP sequence to ensure that the autocorrelation operation accurately matches the periodic characteristics.

[0121] The essence of performing autocorrelation operation on the cross-correlation value at 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 can be obtained than the cross-correlation peak (that is, the two cross-correlation peak values are multiplied).

[0122] 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 each time a new autocorrelation result is obtained, 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, the window length of this window is 100 sampling points.

[0123] 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.

[0124] Accumulation within a certain window range of autocorrelation can better suppress the interference of noise and multipath effects. For details, please refer to Figure 4 and Figure 5 . Figure 4 is the autocorrelation simulation result diagram in the case of OFDMA (4 users) with noise (-10 dB). It can be seen from Figure 4 that 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 is the simulation result diagram 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.

[0125] 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.

[0126] 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.

[0127] According to the obtained candidate synchronization peak position, set a fixed window length A to store the synchronized autocorrelation accumulation values. For example, use 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 the accurate synchronization peak.

[0128] 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 peaks of all effective multipath components are 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.

[0129] 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 lengths of window A and window B are inconsistent, and generally window A is smaller than window B.

[0130] Subtract the average 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.

[0131] The autocorrelation accumulation value of each sampling point in window A minus the average autocorrelation accumulation value of 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 autocorrelation accumulation value of window B.

[0132] Compare the signal-to-noise ratio SNR with the threshold to determine whether the synchronization peak in the peak interval is a valid peak.

[0133] 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, and it is not accurate to judge whether the synchronization peak is valid through the maximum peak at this time. 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.

[0134] In OFDMA, due to the existence of multipath effects, the position of the maximum peak does not reflect the true synchronization peak position, but 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.

[0135] The above process is a progressive design that reduces noise through symbol cross-correlation, enhances autocorrelation, filters using a dynamic threshold, separates signals and noise through windows A / B, verifies SNR, and corrects multiple peaks. It 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.

[0136] In this embodiment, a frame synchronization device for broadband power line communication is also provided. This device is used to implement the above-described embodiments and preferred implementation manners, and those that have been described will not be repeated. As used hereinafter, the term "module" can be a combination of software and / or hardware that implements 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.

[0137] This embodiment provides a frame synchronization device for broadband power line communication, as Figure 6 shown, including:

[0138] A cross-correlation module 601, configured to perform symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence;

[0139] 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;

[0140] A candidate peak determination module 603, configured to determine candidate peak positions based on the absolute values of the autocorrelation accumulation values in the autocorrelation accumulation value sequence;

[0141] A window definition module 604, configured to determine a synchronization peak window centered on the candidate peak positions and determine a noise evaluation window in a region that does not overlap with the synchronization peak window;

[0142] A validity judgment module 605, configured to determine 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;

[0143] 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.

[0144] In an alternative implementation manner, the cross-correlation module 601 is specifically configured to:

[0145] Perform symbol processing on the received signal to obtain symbol data that retains the amplitude;

[0146] Perform addition and subtraction operations on the symbol data and the local synchronization preamble sequence to generate a cross-correlation value sequence.

[0147] In an alternative embodiment, the autocorrelation module 602 is specifically configured to:

[0148] 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;

[0149] 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.

[0150] In an alternative embodiment, the candidate peak determination module 603 is specifically configured to:

[0151] Traverse the autocorrelation accumulation value sequence based on a preset initial threshold;

[0152] 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;

[0153] 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;

[0154] 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.

[0155] In an alternative embodiment, the window definition module 604 is specifically configured to:

[0156] 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 valid multipath components.

[0157] In an alternative embodiment, the window definition module 604 is further configured to:

[0158] 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.

[0159] In an alternative embodiment, the validity judgment module 605 is specifically configured to:

[0160] Extract the average value of the autocorrelation accumulation values within the noise evaluation window as the noise average energy;

[0161] 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;

[0162] Accumulate and average the signal energy to obtain the signal power;

[0163] Perform a ratio operation on the signal power and the average noise energy to obtain the signal-to-noise ratio;

[0164] If the signal-to-noise ratio is greater than the preset threshold, determine that the candidate peak is valid.

[0165] In an alternative embodiment, the validity determination module 605 is further configured to:

[0166] 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.

[0167] In an alternative embodiment, the frame synchronization module 606 is specifically configured to:

[0168] Extract a preset number of peaks with the largest amplitudes from the autocorrelation accumulation values within the synchronization peak window;

[0169] Perform an averaging operation on the sampling point positions corresponding to the preset number of peaks to obtain the target synchronization peak position.

[0170] The further function 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.

[0171] 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.

[0172] This application embodiment also provides a computer device having the above Figure 6 shown frame synchronization device for broadband power line communication.

[0173] Please refer to Figure 7 , Figure 7 which is a schematic structural diagram of a computer device provided by an alternative embodiment of this application. As shown in Figure 7As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. Each component communicates with each other using different buses and can be installed on a common motherboard or 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 alternative embodiments, 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 (for example, as a server array, a set of blade servers, or a multi-processor system). Figure 7 Taking one processor 10 as an example in

[0174] The processor 10 can be a central processing unit, a network processor, or a combination thereof. Among them, the 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 generic array logic, or any combination thereof.

[0175] 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.

[0176] The memory 20 can include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the computer device. In addition, the memory 20 can include high-speed random access memory and can also include non-transitory memory, such as at least one disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some alternative embodiments, the memory 20 can optionally include a memory remotely set relative to the processor 10, and these remote memories can 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.

[0177] The memory 20 can include volatile memory, such as random access memory; the memory can also include non-volatile memory, such as flash memory, a hard disk, or a solid-state drive; the memory 20 can also include a combination of the above types of memory.

[0178] 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 by a bus or other means. Figure 7 Take the connection by bus as an example.

[0179] The input device 30 can receive input digital or character information, and generate key signal inputs related to the user settings and function controls 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 (e.g., an LED), and a haptic feedback device (e.g., 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.

[0180] The embodiment of the present application also provides a computer-readable storage medium. The method according to the embodiment 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 by downloading through a network and originally stored in a remote storage medium or a non-transitory machine-readable storage medium and will be stored in a local storage medium, so that the method described herein can be stored as such software processing 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 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 method shown in the above embodiments is implemented.

[0181] A part of the present application can be applied as a computer program product, such as 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 called or provided. Those skilled in the art should be able to understand that the forms of existence of computer program instructions in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways for computer program instructions to be executed by a computer include, but are not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions 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.

[0182] Although embodiments of the present application have been 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, and such modifications and variations 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; 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 positions, and determining a noise evaluation window in a region without overlap with the synchronization peak window; Judging 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; If it is judged 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; 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; 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 multiplication 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 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.

2. The method according to claim 1, characterized in that, The determining candidate peak positions based on the absolute values of the autocorrelation accumulation values in the autocorrelation accumulation value sequence includes: Traversing 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, 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 that the absolute value of the autocorrelation accumulation value exceeds the updated threshold subsequently, 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.

3. The method according to claim 1, wherein The determining the synchronization peak window includes: [[ID= 4. The method according to claim 3, wherein ​ ​ 5. The method according to claim 1, wherein ​ ​ ​ ​ ​ If the signal-to-noise ratio is greater than a preset threshold, it is determined that the candidate peak is valid.

6. 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.

7. The method according to claim 1, wherein 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.

8. 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; An effectiveness judgment module for judging the effectiveness 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; Wherein, the performing symbol cross-correlation calculation on the received signal to generate a cross-correlation sequence includes: Performing symbol 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; The sequentially 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 multiplication 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 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.

Images