A method and system for identifying unknown OFDM signal frame structure parameters

Abstract

The present application provides a method and system for identifying unknown OFDM signal frame structure parameters, which relates to the field of drone detection, including: receiving an unknown OFDM signal frame sequence sent by a transmitting device in an OFDM system, intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence; calculating the signal bandwidth of the unknown OFDM signal frame, using the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame, and performing an autocorrelation operation on the first sampled signal frame; using the CP of each OFDM symbol in the first sampled signal frame as a reference feature, identifying the maximum peak and the second largest peak in the autocorrelation operation result, and calculating the sampling point difference between the maximum peak and the second largest peak; and identifying the frame structure parameters of the OFDM system according to the sampling point difference. The present application improves the recognition accuracy and reliability of the frame structure parameters.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of drone detection technology, and in particular to a method and system for identifying unknown orthogonal frequency division multiplexing (OFDM) signal frame structure parameters. Background Art

[0002] In the field of drone detection, the digital image transmission signals used by drones are all non-cooperative reception for the receiving device. Non-cooperative reception means that the receiving device does not understand the signal transmitted by the sending device. It is necessary to analyze and study the signals of the sending device collected in advance. After extracting the frame structure parameters of the transmitted signal, it can receive and demodulate the subsequent signals. Therefore, before analyzing and studying the unknown OFDM signal frame, it is usually necessary to know the frame structure parameters of the signal physical layer, and how to extract the unknown OFDM signal frame structure parameters is a difficult problem.

[0003] The traditional methods used to identify unknown OFDM signal frame structure parameters are computationally intensive and the principles are abstract and difficult to understand. For example, the OFDM signal subcarrier wave number estimation method based on high-order cumulants uses the secondary spectrum of the received signal to estimate the number of OFDM subcarriers, performs wavelet decomposition on the received signal to extract wavelet decomposition coefficients to achieve blind estimation of the number of subcarriers, uses the best approximation filter to estimate the number of subcarriers of OFDM signals, and uses the music algorithm to estimate the number of subcarriers of OFDM signals. These algorithms are all used to identify the number of subcarriers of OFDM signals, and do not identify other parameters (such as subcarrier spacing, actual sampling rate, etc.), and require the actual sampling rate to be known. At the same time, these methods are suitable for subcarrier identification under low signal-to-noise ratio conditions. Under high signal-to-noise ratio and unknown actual sampling rate, there are technical problems of low recognition accuracy and poor reliability of unknown OFDM signal frame structure parameters. Summary of the invention

[0004] The embodiments of the present application provide a method and system for identifying unknown OFDM signal frame structure parameters, so as to solve the problems of low accuracy and poor reliability in identifying unknown OFDM signal frame structure parameters in the prior art.

[0005] In a first aspect, an embodiment of the present application provides a method for identifying unknown OFDM signal frame structure parameters, wherein the method is applied to a receiving device in an OFDM system, including:

[0006] Receiving an unknown orthogonal frequency division multiplexing (OFDM) signal frame sequence sent by a transmitting device in an OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence;

[0007] Calculating a signal bandwidth of an unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, and performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function to obtain an autocorrelation operation result;

[0008] The cyclic prefix (CP) of each OFDM symbol in the first sampling signal frame is used as a reference feature, and the peak detection is performed on the autocorrelation operation result to determine the position and amplitude of all peaks, and the peak with the largest amplitude is selected from all peaks as the maximum peak, and the peak with the second largest amplitude is selected as the second largest peak, and the sampling point difference between the maximum peak and the second largest peak is calculated according to the position of the maximum peak and the position of the second largest peak;

[0009] According to the sampling point difference, the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device are identified, and corresponding service processing is performed according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0010] Optionally, when the service requirement includes data recovery, identifying, according to the sampling point difference, a frame structure parameter of an OFDM system corresponding to the service requirement of the receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0011] Use the sampling point difference to perform preliminary analysis on the unknown OFDM signal frame and obtain the subcarrier spacing;

[0012] Calculate the number of subcarriers according to the subcarrier spacing and in combination with CP characteristics;

[0013] Based on the number of subcarriers and the subcarrier spacing, resampling the unknown OFDM signal frame to generate a second sampled signal frame;

[0014] In combination with the subcarrier spacing and the number of subcarriers, an improved maximum likelihood estimation method is used to recover the lost data segment from the second sampling signal frame to ensure high-accuracy data reconstruction.

[0015] Optionally, resampling the unknown OFDM signal frame based on the number of subcarriers and the subcarrier spacing to generate a second sampled signal frame includes:

[0016] Determine the product of the subcarrier spacing and the number of subcarriers as the actual sampling rate;

[0017] Based on the actual sampling rate, the unknown OFDM signal frame is resampled to obtain a second sampled signal frame.

[0018] Optionally, when the service demand also includes signal monitoring, identifying, according to the sampling point difference, a frame structure parameter of an OFDM system corresponding to the service demand of the receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0019] Calculate the CP length and the number of OFDM symbols of the unknown OFDM signal frame according to the position of the maximum peak and the position of the second largest peak, the amplitude of the maximum peak and the amplitude of the second largest peak, and the sampling point difference; or calculate the number of sampling points of the second sampling signal frame according to the sampling point difference, and calculate the CP length and the number of OFDM symbols according to the number of sampling points of the second sampling signal frame;

[0020] Based on the CP length and the number of OFDM symbols, the real-time monitoring model is updated to determine the changing trend of the CP length and the number of OFDM symbols. A dynamic threshold early warning mechanism is set according to the changing trend to discover potential problems. The potential problems include: the spectrum efficiency drops to a preset efficiency threshold and the bit error rate rises to a preset bit error rate threshold. A distributed computing framework is introduced to accelerate the update process and the setting process.

[0021] Optionally, calculating the CP length and the number of OFDM symbols according to the number of sampling points of the second sampling signal frame includes:

[0022] Calculating the difference between the number of sampling points and the number of subcarriers;

[0023] According to the difference, intercepting a first sub-signal frame from the second sampling signal frame, and according to the number of sub-carriers and the number of sampling points, intercepting a second sub-signal frame;

[0024] Performing a dot product on the first sub-signal frame and the second sub-signal frame to obtain a first intermediate signal frame;

[0025] Using one quarter of the number of subcarriers as the length of a sliding window, and performing sliding addition on elements in the first intermediate signal frame according to the length of the sliding window to obtain a second intermediate signal frame;

[0026] performing an absolute value operation on the second intermediate signal frame to obtain a third intermediate signal frame;

[0027] Calculating position marker data corresponding to all peak values ​​in the third intermediate signal frame, and storing the position marker data corresponding to all peak values ​​in a first vector in chronological order;

[0028] Differentiate the first vector to obtain the second vector;

[0029] The mean value of the second vector is determined as the CP length, and the number of sampling points corresponding to the first vector is determined as the number of OFDM symbols.

[0030] Optionally, when the service requirement is security analysis, identifying, according to the sampling point difference, a frame structure parameter of an OFDM system corresponding to the service requirement of the receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0031] Analyzing whether an unknown OFDM signal frame has an abnormal pattern according to the sampling point difference;

[0032] Based on the results of abnormal pattern analysis, machine learning algorithms are applied to identify potential security threat events;

[0033] Based on the potential security threat events, quantum key distribution technology is used to build a secure communication link to ensure the integrity and confidentiality of data during transmission;

[0034] Deploy smart contract automated response strategies, and when a potential security threat event is determined to be a real security threat event, execute defense measures corresponding to the type of real security threat event.

[0035] Optionally, when the service requirement is network optimization, identifying, according to the sampling point difference, a frame structure parameter of an OFDM system corresponding to the service requirement of a receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0036] Use the sampling point difference to perform preliminary analysis on the unknown OFDM signal frame and obtain the subcarrier spacing;

[0037] According to the subcarrier spacing, the first sampled signal frames corresponding to different unknown OFDM signal frames in the unknown OFDM signal frame sequence are collected, and the network performance information to be optimized is found by using big data analysis technology;

[0038] According to the network performance to be optimized information, dynamically adjusting the subcarrier spacing using a reinforcement learning algorithm to obtain an adjusted subcarrier spacing;

[0039] Generate an adaptive coding scheme based on the adjusted subcarrier spacing to automatically select the optimal coding method under different network conditions;

[0040] The software-defined network architecture is used to allocate resources to the receiving device according to the adaptive coding scheme.

[0041] In a second aspect, an embodiment of the present application provides a system for identifying unknown OFDM signal frame structure parameters, wherein a receiving device applied to an OFDM system includes:

[0042] A receiving module, used for receiving an unknown orthogonal frequency division multiplexing OFDM signal frame sequence sent by a transmitting device in an OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence;

[0043] A calculation resampling module, used for calculating the signal bandwidth of the unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, and performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function to obtain an autocorrelation operation result;

[0044] a detection and calculation module, configured to use the cyclic prefix CP of each OFDM symbol in the first sampling signal frame as a reference feature, perform peak detection on the autocorrelation operation result, determine the positions and amplitudes of all peaks, select the peak with the largest amplitude from all peaks as the maximum peak, select the peak with the second largest amplitude as the second largest peak, and calculate the sampling point difference between the maximum peak and the second largest peak according to the position of the maximum peak and the position of the second largest peak;

[0045] An identification module is used to identify the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device according to the sampling point difference, and perform corresponding service processing according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0046] In a third aspect, an embodiment of the present application provides a computing device, comprising a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to implement a method for identifying an unknown OFDM signal frame structure parameter as described in any one of the first aspects.

[0047] In a fourth aspect, an embodiment of the present application provides a computer storage medium storing a computer program. When the computer program is executed by a computer, it implements a method for identifying unknown OFDM signal frame structure parameters as described in any one of the first aspects.

[0048] The embodiment of the present application provides a method for identifying unknown OFDM signal frame structure parameters, which is applied to a receiving device in an OFDM system, including: receiving an unknown orthogonal frequency division multiplexing OFDM signal frame sequence sent by a sending device in the OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence; calculating the signal bandwidth of the unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function, and obtaining an autocorrelation operation result; and performing an autocorrelation operation on each OFDM signal frame in the first sampled signal frame. The cyclic prefix CP of the M symbol is used as a reference feature, and peak detection is performed on the autocorrelation operation result to determine the position and amplitude of all peaks, and the peak with the largest amplitude is selected from all peaks as the maximum peak, and the peak with the second largest amplitude is selected as the second largest peak, and the sampling point difference between the maximum peak and the second largest peak is calculated according to the position of the maximum peak and the position of the second largest peak; according to the sampling point difference, the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device are identified, and corresponding service processing is performed according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0049] In the embodiment of the present application, the method for identifying unknown OFDM signal frame structure parameters enables the receiving device to automatically and intelligently parse and adapt to OFDM signals of different configurations without prior knowledge, thereby optimizing resource utilization efficiency. In addition, the embodiment of the present application enhances the performance and stability of the communication link by accurately and quickly identifying key frame structure parameters.

[0050] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 A flowchart of a method for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application;

[0053] Figure 2 A structural diagram of a system for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application;

[0054] Figure 3A flowchart of another method for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application;

[0055] Figure 4 A schematic diagram of the structure of another unknown OFDM signal frame structure parameter identification system provided in an embodiment of the present application;

[0056] Figure 5 A schematic diagram of the structure of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0058] In some of the processes described in the specification and claims of this application and the above-mentioned figures, multiple operations that appear in a specific order are included, but it should be clearly understood that these operations may not be executed in the order in which they appear in this article or executed in parallel. The sequence numbers of the operations, such as 11, 12, etc., are only used to distinguish between different operations, and the sequence numbers themselves do not represent any execution order. In addition, these processes may include more or fewer operations, and these operations may be executed in sequence or in parallel. It should be noted that the descriptions of "first", "second", etc. in this article are used to distinguish different messages, devices, modules, etc., do not represent the order of precedence, and do not limit the "first" and "second" to different types.

[0059] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0060] Figure 1 A flowchart of a method for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application, such as Figure 1 As shown, the method is applied to a receiving device in an OFDM system, comprising:

[0061] S11. Receive an unknown orthogonal frequency division multiplexing (OFDM) signal frame sequence sent by a transmitting device in an OFDM system, and intercept an unknown OFDM signal frame from the unknown OFDM signal frame sequence.

[0062] It should be understood that in this embodiment, the collected unknown OFDM system signal is intercepted into multiple segments, each of which contains a complete OFDM signal frame, and the interception is based on the power change of the signal.

[0063] It should also be understood that IQ data refers to "In-phase and Quadrature" data, which is used to describe the two components of an unknown OFDM signal frame: I stands for In-phase, which means the in-phase component, which refers to the signal part that is in phase with the carrier signal. Q stands for Quadrature, which means the quadrature component, which refers to the signal part that has a 90-degree phase difference with respect to the carrier signal. IQ data is the representation of the unknown OFDM signal frame in the time domain, and the unknown OFDM signal frame is the result of organizing these IQ data according to a specific structure. Specifically, the OFDM system transmits a composite signal composed of multiple subcarriers. Each OFDM symbol is actually a group of data transmitted simultaneously, which is distributed on each subcarrier in the frequency domain. When these symbols are converted to the time domain for actual transmission, they exist in the form of complex values, namely IQ data. Therefore, the received IQ data stream is actually a continuous sequence of OFDM symbols. A complete OFDM signal frame usually contains multiple OFDM symbols, and may also include auxiliary information such as pilot symbols and synchronization symbols. There are also guard intervals in the OFDM signal frame, such as cyclic prefix CP, which is used to prevent inter-symbol interference. Each OFDM signal frame has its start and end position, as well as a specific time length. In summary, IQ data is the basic element that constitutes the OFDM signal frame, and the OFDM signal frame defines how this data is organized in time and frequency.

[0064] S12, calculating the signal bandwidth of the unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function, and obtaining an autocorrelation operation result.

[0065] The preset autocorrelation function may be:

[0066] ;

[0067] in, is the result of autocorrelation operation, is the discrete time signal in the first sampling signal frame, i.e., the sampling point, represents the complex conjugate of a discrete-time signal and is shifted in time by , N is the number of sampling points, used to indicate the length of the first sampling signal frame, represents the time delay, that is, the amount of lag considered when calculating the autocorrelation.

[0068] It should be understood that according to the measured signal bandwidth (Bandwidth, bw) and the Nyquist sampling theorem, the input signal (i.e., the unknown OFDM signal frame) is resampled according to the signal bandwidth bw. At this time, it is known that the resampling rate is smaller than the actual sampling rate of the OFDM system, because for the IQ sampled signal, the signal sampling rate must be greater than or equal to the signal bandwidth to ensure that the Nyquist sampling theorem is met.

[0069] It should also be understood that the autocorrelation operation refers to comparing a signal with itself at different time offsets to find a repetitive pattern. In the embodiment of the present application, the autocorrelation operation can be performed on the resampled IQ signal. The result of the autocorrelation operation is an array, and a data in the array represents the autocorrelation value of a sampling point. For example, the result of the autocorrelation operation is is [1000,...,850,700,...,], where 1000 is the maximum peak, corresponding to the sampling point lag0; 850 is the second largest peak, corresponding to the sampling point lag16; 700 is the peak other than the maximum peak and the second largest peak, corresponding to the sampling point lag18. The 0 in lag0 and the 16 in lag16 indicate the numbers of the sampling points.

[0070] S13. Use the cyclic prefix CP of each OFDM symbol in the first sampling signal frame as a reference feature, perform peak detection on the autocorrelation operation result, determine the positions and amplitudes of all peaks, select the peak with the largest amplitude from all peaks as the maximum peak, select the peak with the second largest amplitude as the second largest peak, and calculate the sampling point difference between the maximum peak and the second largest peak according to the position of the maximum peak and the position of the second largest peak.

[0071] It should be understood that the sampling point difference between the maximum peak and the second largest peak refers to the result of the difference between the number of the sampling point corresponding to the maximum peak and the number of the sampling point corresponding to the second largest peak, wherein the sampling point corresponding to the maximum peak refers to the sampling point corresponding to the largest autocorrelation value, and the sampling point corresponding to the second largest peak refers to the sampling point corresponding to the autocorrelation value with a larger autocorrelation value. The sampling point difference between the maximum peak and the second largest peak is also called the peak interval between the maximum peak and the second largest peak. The maximum peak usually corresponds to zero offset, indicating that the signal matches itself perfectly, while the second largest peak appears at a periodic interval, reflecting the periodic characteristics of the OFDM symbol. It should also be understood that the cyclic prefix CP in the OFDM system is a key component.

[0072] S14. According to the sampling point difference, identify the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device, and perform corresponding service processing according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0073] It should be understood that CP is a key component that plays several important roles in signal processing and transmission. The cyclic prefix has the following advantages for OFDM systems:

[0074] 1. Suppress multipath interference and inter-symbol interference: The cyclic prefix forms a guard interval by copying a section of the signal at the end of the OFDM symbol and placing it at the head, thereby avoiding interference between adjacent OFDM symbols caused by multipath propagation, that is, suppressing inter-symbol interference (ISI). The length of the cyclic prefix must be greater than the multipath delay of the channel to ensure that each OFDM symbol can be fully received without interference from the previous symbol when performing the inverse fast Fourier transform (FFT) at the receiving end.

[0075] 2. Convert linear convolution to circular convolution: The existence of cyclic prefix allows the linear convolution of the signal and the channel to be converted into circular convolution in the OFDM system. This conversion is the premise for using FFT for single-tap equalization, because only circular convolution can ensure that within the sliding window of FFT, the convolution output of the signal depends only on the current OFDM symbol and is not affected by the previous symbol.

[0076] 3. Maintaining subcarrier orthogonality: The subcarriers in the OFDM system maintain orthogonality through the cyclic prefix, which is crucial to maintaining the spectrum efficiency of the OFDM system.

[0077] 4. Time synchronization: The cyclic prefix also helps the receiver in time synchronization because it provides a known signal segment that can be used to estimate and correct the time offset.

[0078] 5. Suppressing adjacent channel interference: The cyclic prefix helps suppress interference between adjacent channels by inserting a guard interval between OFDM symbols.

[0079] 6. Impact on system performance: The length of the cyclic prefix has a direct impact on the performance of the OFDM system. Different cyclic prefix lengths will have different effects on the system's bit error rate (BER) and signal-to-noise ratio (SNR). Studies have shown that the best BER value can be obtained when the cyclic prefix length is 1 / 4 of the inverse fast Fourier transform size 512.

[0080] 7. Optimization: Because the cyclic prefix itself does not carry data information, when designing an OFDM system, the relationship between the cyclic prefix length and system performance can be weighed to optimize the overall design.

[0081] Based on the above advantages of the cyclic prefix CP, it is widely used in OFDM systems. The present application is based on the use of the cyclic prefix in the signal of the OFDM system, making the identification method of the unknown OFDM signal frame structure parameters more universal.

[0082] By executing S11 to S14, the embodiment of the present application identifies a variety of frame structure parameters, and utilizes the structure of CP to identify the sampling point difference, and then calculates the actual sampling rate of the OFDM system. The embodiment of the present application obtains the demodulation parameters of the signal physical layer according to the frame structure parameters, and then receives and demodulates the signal according to the obtained demodulation parameters, which can improve the accuracy and reliability of frame structure parameter identification under high signal-to-noise ratio conditions.

[0083] Figure 2 A structural diagram of a system for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application; the system for identifying unknown OFDM signal frame structure parameters includes: a signal interception unit 21, a subcarrier spacing estimation and sampling rate correction unit 22, and a CP length estimation and frame structure identification unit 23.

[0084] The signal interception unit 21 is used to execute Figure 1 In step S11 of the above, the task of the signal interception unit 21 is to accurately identify and intercept the data segments that meet the requirements of the OFDM signal frame structure from the continuous IQ data stream, providing a basis for subsequent parameter estimation and signal analysis. The subcarrier spacing estimation and sampling rate correction unit 22 includes a subcarrier spacing estimation module 221 and a sampling rate correction module 222, wherein the subcarrier spacing estimation module 221 is used to perform Figure 1 The sampling rate correction unit 22 executes part of S14, and the CP length estimation and frame structure identification unit 23 executes the remaining part of S14.

[0085] In general, the signal interception unit 21 intercepts a complete frame of IQ data according to the power change of the input signal, and reports the data to the subcarrier spacing estimation and sampling rate correction unit 22. The subcarrier spacing estimation and sampling rate correction unit 22 uses the subcarrier spacing estimation module 221 to perform autocorrelation operation on the input complex IQ signal, and extracts the sampling point difference between the maximum peak and the second largest peak of the correlation result, calculates the sampling rate parameter, and uses the sampling rate correction module 222 to resample the input signal, and reports the resampled data to the CP length estimation and frame structure identification unit 23, which performs delayed correlation calculation and accumulation on the input signal, and finally outputs the identified CP length, and outputs the frame structure features after filtering the sampling point difference, and the frame structure features include the number of OFDM symbols, subcarrier spacing, subcarrier data, CP length and actual sampling rate.

[0086] In order to facilitate the description of the functions of the above units or modules, a flowchart of another method for identifying unknown OFDM signal frame structure parameters is provided. Figure 3 A flow chart of another method for identifying unknown OFDM signal frame structure parameters provided in an embodiment of the present application is shown as follows: Figure 3 As shown, another method for identifying unknown OFDM signal frame structure parameters includes:

[0087] S31. Intercept an unknown OFDM signal frame. The specific description of this step is consistent with the explanation of S11 and will not be repeated here. S32. Calculate the signal bandwidth bw; S33. Use the signal bandwidth as a known sampling rate to resample the unknown OFDM signal frame; S34. Perform an autocorrelation operation on the first sampled signal frame. The specific description of steps S32 to S34 is consistent with the explanation of S12 and will not be repeated here. S35. Calculate the sampling point difference between the maximum peak and the second largest peak. The specific description of S35 is consistent with the explanation of S13 and will not be repeated here. S36. Calculate the actual sampling rate, the number of subcarriers and the subcarrier spacing. S37. Based on the actual sampling rate, resample the unknown OFDM signal frame. S38. Calculate the CP length and the number of OFDM symbols based on the number of subcarriers and the actual sampling rate. The specific description of S36 to S38 is consistent with the explanation of S14 and will not be repeated here. Among them, the subcarrier spacing estimation module 221 executes the above steps S32 to S36, the sampling rate correction module 222 executes the above step S37, and the CP length estimation and frame structure identification unit 23 executes the above step S38.

[0088] In a possible embodiment, when the service requirement includes data recovery, S14, identifying, according to the sampling point difference, a frame structure parameter of the OFDM system corresponding to the service requirement of the receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0089] Step 141: Perform a preliminary analysis on the unknown OFDM signal frame using the sampling point difference to obtain the subcarrier spacing.

[0090] Specifically, in this embodiment, the ratio of the known sampling rate to the sampling point difference may be determined as the subcarrier spacing. This step may be implemented using the following exemplary formula:

[0091] ;

[0092] in, is the subcarrier spacing, exemplarily, =20×10 6 / 100=200×10 3 =200 kHz. is a known sampling rate, is the sampling point difference, which is exemplarily the difference between the number of the sampling point corresponding to the maximum peak (e.g. 101) and the number of the sampling point corresponding to the second largest peak (e.g. 100). In another exemplary embodiment, the number of the sampling point corresponding to the maximum peak is 16 - the number of the sampling point corresponding to the second largest peak is 0 = the sampling point difference is 16.

[0093] Step 142: Calculate the number of subcarriers based on the subcarrier spacing and the CP characteristics, or calculate the number of subcarriers based on the sampling point difference.

[0094] Specifically, in this embodiment, twice the sampling point difference value can be used as a designated parameter, the logarithm of the designated parameter is taken to obtain a logarithmic value, the logarithmic value is rounded to obtain an integer, the sum of the integer and the preset value is used as a power, the power is rounded, and the rounded power of 2 is determined as the number of subcarriers. Therefore, step 142 can be implemented using the following exemplary formula:

[0095] ;

[0096] in, is the number of subcarriers, is the sampling point difference, is a specified parameter, 1 is an exemplary preset value, Express Round down. The preset value may also be other values, which are not specifically limited in the present embodiment. The present embodiment applies this logarithmic transformation because in an OFDM system, the number of subcarriers is usually a power of 2 (such as 32, 64, 128, 256, 512, etc.).

[0097] Accordingly, the embodiment of the present application determines the number of subcarriers by using logarithmic transformation and power processing, and determines the subcarrier spacing by using the ratio of the known sampling rate to the sampling point difference. This method not only ensures that the calculation result conforms to the characteristic that the number of subcarriers in the OFDM system is usually a power of 2, but also simplifies the complexity of the parameter identification process. This method effectively maps the results of signal analysis to actual application requirements, improves the accuracy and efficiency of parameter estimation, and enables the receiving device to quickly and accurately adapt to different OFDM signal configurations.

[0098] Step 143: resample the unknown OFDM signal frame based on the number of subcarriers and the subcarrier spacing to generate a second sampled signal frame.

[0099] Specifically, step 143, based on the number of subcarriers and the subcarrier spacing, resampling the unknown OFDM signal frame to generate a second sampled signal frame, includes:

[0100] Step a1: The product of the subcarrier spacing and the number of subcarriers is determined as the actual sampling rate.

[0101] Since the subcarrier spacing is the ratio of the known sampling rate to the sampling point difference, step b1 can use the following formula:

[0102] ;

[0103] in, is the actual sampling rate, is a known sampling rate, is the sampling point difference, is the number of subcarriers. =20×10 6 Hz, N=128, =100, then 25.6×10 6 Hz.

[0104] By executing a1, the embodiment of the present application provides an efficient, simple and reliable way to determine the actual sampling rate, realizes seamless connection from signal analysis to system parameter configuration, and ensures that the receiving device can accurately adjust its own sampling rate setting according to the received signal characteristics, thereby ensuring the correctness of the demodulation process and the accuracy of data recovery. In addition, this method is based on the known sampling rate, sampling point difference and number of subcarriers, and the actual sampling rate can be obtained through simple mathematical operations, which not only improves the calculation efficiency, but also simplifies the algorithm implementation and reduces the requirements for the hardware performance of the receiving device. More importantly, since this method relies on accurate measurement of the intrinsic characteristics of the signal (such as subcarrier spacing) and logical reasoning (such as the power relationship of the number of subcarriers), it also has high adaptability and reliability when facing OFDM signals with different configurations or unknown, further enhancing the robustness and flexibility of the receiving system.

[0105] Step a2: resample the unknown OFDM signal frame based on the actual sampling rate to obtain a second sampled signal frame. Exemplarily, the second sampled signal frame is RX.

[0106] By executing step a2, the embodiment of the present application resamples the unknown OFDM signal frame based on the actual sampling rate, which can improve the quality and reliability of receiving the unknown OFDM signal frame.

[0107] Step 144: In combination with the subcarrier spacing and the number of subcarriers, an improved maximum likelihood estimation method is used to recover the lost data segment from the second sampling signal frame to ensure high-accuracy data reconstruction.

[0108] By executing steps 141 to 144, the embodiment of the present application is provided with a simple calculation process for the number of subcarriers and the subcarrier spacing. In addition, the embodiment of the present application is also provided with a simple calculation process for the actual sampling rate, CP length, and number of OFDM symbols. Exemplarily, in a possible embodiment, when the service demand also includes signal monitoring, step S14, based on the sampling point difference, identifies the frame structure parameters of the OFDM system corresponding to the service demand of the receiving device, and performs corresponding service processing based on the identified frame structure parameters, including:

[0109] Step 145: Calculate the CP length and the number of OFDM symbols of the unknown OFDM signal frame according to the position of the maximum peak and the position of the second largest peak, the amplitude of the maximum peak and the amplitude of the second largest peak, and the sampling point difference; or, calculate the number of sampling points of the second sampling signal frame according to the sampling point difference, and calculate the CP length and the number of OFDM symbols according to the number of sampling points of the second sampling signal frame.

[0110] In step 145, the CP length and the number of OFDM symbols are calculated according to the number of sampling points of the second sampling signal frame, including:

[0111] Step b1, calculate the difference between the number of sampling points and the number of subcarriers. Exemplarily, the number of sampling points of the second sampling signal frame, len = length(RX).

[0112] Step b2: According to the difference, a first sub-signal frame is intercepted from the second sampling signal frame, and according to the number of sub-carriers and the number of sampling points, a second sub-signal frame is intercepted.

[0113] It should be understood that the first sub-signal frame is the first segment signal, that is, RX1 = RX(1:len-N), and the second sub-signal frame is the second segment signal, that is, RX2 = RX(N:len), wherein, is the number of subcarriers, and len is the number of sampling points of the second sampling signal frame. Exemplarily, RX1 = RX(1:160-128). RX2 = RX(128:160).

[0114] Step b3, perform a dot product on the first sub-signal frame and the second sub-signal frame to obtain a first intermediate signal frame. Exemplarily, step b3 can be represented by the following formula: y1 = RX1.*RX2; wherein y1 is the first intermediate signal frame, RX1 is the first sub-signal frame, and RX2 is the second sub-signal frame.

[0115] Step b4: Taking one quarter of the number of subcarriers as the length of the sliding window, and performing sliding addition on the elements in the first intermediate signal frame according to the length of the sliding window to obtain a second intermediate signal frame. Exemplarily, step b4 can be expressed by the following formula:

[0116] ;

[0117] in, is the nth element in the second intermediate signal frame, which is the signal after sliding addition processing. is the nth element in the first intermediate signal frame, which is the signal without sliding addition processing, n is the starting position of the current sliding window, is the number of subcarriers, is the length of the sliding window. =128, =32.

[0118] Step b5: perform an absolute value operation on the second intermediate signal frame to obtain a third intermediate signal frame. Exemplarily, step b5 can be expressed by the following formula: y3 = |y2|, where y3 is the third intermediate signal frame, and |y2| represents the modulus (i.e., amplitude) of the second intermediate signal frame.

[0119] Step b6: Calculate the position marker data corresponding to all peak values ​​in the third intermediate signal frame, and store the position marker data corresponding to all peak values ​​in the first vector in chronological order. It should be understood that the position marker data is consistent with the interpretation of the sampling point number in the embodiment of the present application.

[0120] Optionally, in step b6, the embodiment of the present application may be based on the subcarrier spacing Or based on the number of subcarriers Calculate the position marker data corresponding to all peak values. The position marker data can be represented by a position subscript, and the first vector is P. For example, the peak values ​​in y3 are detected as y3

[10] =50 and y3

[30] =45, then the first vector P =[10, 30].

[0121] Step b7: Differentiate the first vector to obtain the second vector. Exemplarily, step b7 can be implemented by using the following formula: P1=P(2:end) – P(1:end-1), where P1 is the second vector and end is the last position subscript.

[0122] Step b8: Determine the mean of the second vector as the CP length, and determine the number of sampling points corresponding to the first vector as the number of OFDM symbols. It should be understood that the mean of the second vector P1 is calculated, and the mean is the CP length, and the length of the first vector P is calculated, and the length of the first vector P is the number of OFDM symbols of the unknown OFDM signal frame.

[0123] By executing steps b1 to b8, the embodiment of the present application provides a series of accurate signal processing techniques, including point multiplication, sliding addition, absolute value operation and peak detection, etc., to realize the automatic identification of the cyclic prefix CP length and the number of OFDM symbols in the unknown OFDM signal frame. This method can not only accurately capture the periodic characteristics in the signal, so as to reliably determine the position and length of the CP, but also effectively enhance the robustness and accuracy of the signal analysis by gradually processing multiple intermediate signal frames. In particular, using one-fourth of the number of subcarriers as the sliding window length for sliding addition can further improve the detection accuracy of the CP boundary while ensuring the calculation efficiency; and by determining the CP length by taking the differential mean of the peak position mark data, and taking the number of peak positions as the number of OFDM symbols, an intuitive and efficient method is provided to parse the OFDM frame structure. Ultimately, these steps work together to ensure that the receiving device can quickly and accurately identify and adapt to different OFDM configurations in a complex and changeable communication environment, improve the performance and reliability of the system, and also simplify the implementation process and reduce the requirements for the hardware performance of the receiving device.

[0124] In addition, the embodiment of the present application provides a systematic method to accurately parse the structure of OFDM signals by resampling unknown OFDM signal frames based on the actual sampling rate, calculating the number of sampling points, intercepting sub-signal frames according to the number of subcarriers, and finally determining the CP length and the number of OFDM symbols. This method not only ensures that the receiving device can accurately adjust to the sampling rate that matches the transmitting device, thereby improving the accuracy of signal demodulation, but also effectively separates the cyclic prefix CP and the valid data part through the difference analysis of the number of sampling points and the number of subcarriers, thereby realizing the automatic identification of the CP length and the number of OFDM symbols. This step simplifies the parameter estimation process, enhances the robustness and flexibility of the algorithm, enables the receiving device to quickly adapt to and correctly parse the received OFDM signal in an unknown or changing communication environment, and improves the performance and reliability of the system. In addition, the implementation of this method is relatively simple and easy to integrate into existing receiving devices, which promotes the practical application and development of technology.

[0125] Step 146: Based on the CP length and the number of OFDM symbols, update the real-time monitoring model to determine the changing trend of the CP length and the number of OFDM symbols, and set a dynamic threshold warning mechanism according to the changing trend to discover potential problems. Potential problems include: the spectrum efficiency drops to a preset efficiency threshold and the bit error rate rises to a preset bit error rate threshold. Introduce a distributed computing framework to accelerate the update process and the setting process.

[0126] By executing steps 145 to 146, the embodiment of the present application provides a set of efficient, reliable and easy-to-implement solutions for automatically identifying and configuring the key parameters of OFDM signals, thereby greatly enhancing the performance and adaptability of the receiving system and ensuring the quality and stability of the communication link. Specifically, through a series of associated calculations, the determination of the number of subcarriers, subcarrier spacing and actual sampling rate from the sampling point difference is realized, and the CP length and the number of OFDM symbols are further calculated. This process not only provides the receiving device with the key parameters required for accurate configuration, ensuring that it can accurately demodulate unknown OFDM signals, but also improves the system's ability to parse the OFDM frame structure. By automatically identifying these core parameters, the method simplifies the setting process of the receiving end, enhances the adaptability to different OFDM configurations, and improves the flexibility and robustness of the communication system. In addition, the effectiveness and efficiency of this method enable it to respond quickly in complex communication environments and ensure high-quality data transmission.

[0127] For example, a segment of data containing a complete OFDM signal frame is intercepted from an unknown OFDM system signal, and the data is intercepted based on the signal power change, including 1024 sampling points. Assuming that the calculated signal bandwidth is 5MHz, according to the Nyquist sampling theorem, the signal is resampled to 10 MHz (i.e., twice the signal bandwidth). Example of autocorrelation operation results:

[0128] [1000,...,850,...,700,...][1000,...,850,...,700,...], where 1000 is the maximum peak, corresponding to lag0; 850 is the second largest peak, corresponding to lag16. Maximum peak position: lag0 (1000), second largest peak position: lag16 (850), sampling point difference: 16. Known sampling rate = 20 MHz, sampling point difference is 16. Subcarrier spacing =20MHz / 16=1.25 MHz, number of subcarriers N =32, actual sampling rate =40MHz. The length of the second sampling signal frame RX is 512 sampling points.

[0129] The number of sampling points of the second sampling signal frame is len=512, and the number of subcarriers is N=32. Therefore, the first subsignal frame RX1 = RX(1:len-N) = RX(1:480), and the second subsignal frame RX2 = RX(N:len) = RX(32:512). When N=32, the sliding window length is 8. Assume that the processed second intermediate signal frame is a real number sequence with a length of 473. The third intermediate signal frame y3 can be a real number sequence with a length of 473. Assume that the detected peaks are y3

[10] =50 and y3

[30] =45, then the first vector P = [10, 30]. P1=P(2:end) – P(1:end-1)=[30−10]=

[20] . CP length = second vector mean = 20, number of OFDM symbols = first vector length = 2.

[0130] In a possible embodiment, when the service requirement is security analysis, S14, identifying, according to the sampling point difference, a frame structure parameter of the OFDM system corresponding to the service requirement of the receiving device, and performing corresponding service processing according to the identified frame structure parameter, including:

[0131] Step 147: Analyze whether the unknown OFDM signal frame has an abnormal pattern according to the sampling point difference.

[0132] Step 148: Based on the abnormal pattern analysis results, apply machine learning algorithms to identify potential security threat events.

[0133] Step 149: Based on potential security threat events, use quantum key distribution technology to build a secure communication link to ensure data integrity and confidentiality during transmission.

[0134] Step 150: deploy a smart contract automated response strategy, and when a potential security threat event is determined to be a real security threat event, execute defense measures corresponding to the type of real security threat event.

[0135] By executing steps 147 to 150, the embodiment of the present application constitutes a comprehensive and dynamic security protection system, which can not only effectively detect and identify security threats, but also respond quickly to ensure the security and stability of the communication link. The risk resistance of the overall system is improved through multi-level and multi-dimensional security strategies.

[0136] In a possible embodiment, when the service requirement is network optimization, step S14, identifying the frame structure parameters of the OFDM system corresponding to the service requirement of the receiving device according to the sampling point difference, and performing corresponding service processing according to the identified frame structure parameters, includes:

[0137] Step 151: Perform a preliminary analysis on the unknown OFDM signal frame using the sampling point difference to obtain the subcarrier spacing.

[0138] Step 152: collect the first sampling signal frames corresponding to different unknown OFDM signal frames in the unknown OFDM signal frame sequence according to the subcarrier spacing, and use big data analysis technology to find the information to be optimized for network performance.

[0139] Step 153: According to the information about the network performance to be optimized, the subcarrier spacing is dynamically adjusted using a reinforcement learning algorithm to obtain an adjusted subcarrier spacing.

[0140] Step 154: Generate an adaptive coding scheme according to the adjusted subcarrier spacing to automatically select the optimal coding method under different network conditions.

[0141] Step 155: Use the software defined network architecture to allocate resources to the receiving device according to the adaptive coding scheme.

[0142] By executing steps 151 to 155, the embodiment of the present application forms a complete closed-loop management solution from the precise extraction of parameters to the final resource optimization allocation, which not only improves the analysis capability of unknown OFDM signal frames, but also realizes the intelligent management and optimization of network performance. Its main advantages include: (1) reducing the dependence on manual intervention and realizing automated detection, analysis and optimization. (2) It can quickly adapt to changes in the network environment and provide the best resource allocation and coding strategy. (3) By analyzing a large amount of data, it can not only solve current problems, but also predict and prevent possible challenges in the future. (4) It ensures that the stability and security of the system will not be affected during the network optimization process, which is particularly important in high-demand application scenarios. Ultimately, the overall performance and reliability of the network are improved, allowing the OFDM system to maintain efficient operation in a complex and changing environment.

[0143] Figure 4 A structural diagram of another unknown OFDM signal frame structure parameter identification system provided in an embodiment of the present application, such as Figure 4 As shown, the system is applied to a receiving device in an OFDM system, including:

[0144] The receiving module 41 is used to receive an unknown orthogonal frequency division multiplexing (OFDM) signal frame sequence sent by a transmitting device in an OFDM system, and to intercept an unknown OFDM signal frame from the unknown OFDM signal frame sequence.

[0145] The calculation resampling module 42 is used to calculate the signal bandwidth of the unknown OFDM signal frame, use the signal bandwidth as a known sampling rate, resample the unknown OFDM signal frame to obtain a first sampled signal frame, and perform an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function to obtain an autocorrelation operation result.

[0146] The detection and calculation module 43 is used to use the cyclic prefix CP of each OFDM symbol in the first sampling signal frame as a reference feature, perform peak detection on the autocorrelation operation result, determine the position and amplitude of all peaks, select the peak with the largest amplitude from all peaks as the maximum peak, select the peak with the second largest amplitude as the second largest peak, and calculate the sampling point difference between the maximum peak and the second largest peak according to the position of the maximum peak and the position of the second largest peak.

[0147] The identification module 44 is used to identify the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device according to the sampling point difference, and perform corresponding service processing according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0148] Figure 4The unknown OFDM signal frame structure parameter recognition system can be performed Figure 1 The implementation principle and technical effect of the unknown OFDM signal frame structure parameter identification method described in the illustrated embodiment will not be described in detail. The specific manner in which each module and unit performs operations in the unknown OFDM signal frame structure parameter identification system in the above embodiment has been described in detail in the embodiment of the method, and will not be described in detail here.

[0149] In one possible design, Figure 4 The unknown OFDM signal frame structure parameter recognition system of the embodiment shown can be implemented as a computing device, such as Figure 5 As shown, the computing device may include a storage component 51 and a processing component 52 .

[0150] The storage component 51 stores one or more computer instructions, wherein the one or more computer instructions are called and executed by the processing component 52 .

[0151] The processing component 52 is used for: being applied to a receiving device in an OFDM system, including: receiving an unknown orthogonal frequency division multiplexing OFDM signal frame sequence sent by a sending device in the OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence; calculating the signal bandwidth of the unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function, and obtaining an autocorrelation operation result; and converting the cyclic prefix CP of each OFDM symbol in the first sampled signal frame into a cyclic prefix CP of each OFDM symbol in the first sampled signal frame. As a reference feature, peak detection is performed on the autocorrelation operation result to determine the position and amplitude of all peaks, the peak with the largest amplitude is selected from all peaks as the maximum peak, the peak with the second largest amplitude is selected as the second largest peak, and the sampling point difference between the maximum peak and the second largest peak is calculated according to the position of the maximum peak and the position of the second largest peak; according to the sampling point difference, the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device are identified, and corresponding service processing is performed according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

[0152] The processing component 52 may include one or more processors to execute computer instructions to complete all or part of the steps in the above method. Of course, the processing component may also be implemented by one or more application-specific integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field programmable gate arrays (FPGA), controllers, microcontrollers, microprocessors or other electronic components to perform the above method.

[0153] The storage component 51 is configured to store various types of data to support operations at the terminal. The storage component can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as random access memory (RAM), static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0154] Of course, the computing device may also include other components, such as input / output interfaces, display components, communication components, etc.

[0155] The input / output interface provides an interface between the processing component and the peripheral interface module, which may be an output device, an input device, etc.

[0156] The communication component is configured to facilitate, among other things, wired or wireless communications between the computing device and other devices.

[0157] Among them, the computing device can be a physical device or an elastic computing host provided by a cloud computing platform, etc. In this case, the computing device can refer to a cloud server, and the above-mentioned processing components, storage components, etc. can be basic server resources rented or purchased from the cloud computing platform.

[0158] The present application also provides a computer storage medium storing a computer program, wherein the computer program can achieve the above-mentioned Figure 1 The illustrated embodiment is a method for identifying unknown OFDM signal frame structure parameters.

[0159] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0160] The system embodiment described above is merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art may understand and implement it without creative work.

[0161] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for identifying unknown OFDM signal frame structure parameters, characterized in that: Receiving equipment used in OFDM systems includes: Receiving an unknown orthogonal frequency division multiplexing (OFDM) signal frame sequence sent by a transmitting device in an OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence; Calculating a signal bandwidth of an unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, and performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function to obtain an autocorrelation operation result; The cyclic prefix CP of each OFDM symbol in the first sampling signal frame is used as a reference feature, and the peak value is detected on the autocorrelation operation result to determine the position and amplitude of all peaks, and the peak with the largest amplitude is selected from all peaks as the maximum peak, and the peak with the second largest amplitude is selected as the second largest peak, and the sampling point difference between the maximum peak and the second largest peak is calculated according to the position of the maximum peak and the position of the second largest peak; According to the sampling point difference, the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device are identified, and corresponding service processing is performed according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

2. The method according to claim 1, characterized in that When the service requirement includes data recovery, identifying the frame structure parameters of the OFDM system corresponding to the service requirement of the receiving device according to the sampling point difference, and performing corresponding service processing according to the identified frame structure parameters, including: Use the sampling point difference to perform preliminary analysis on the unknown OFDM signal frame and obtain the subcarrier spacing; Calculate the number of subcarriers according to the subcarrier spacing and in combination with CP characteristics; Based on the number of subcarriers and the subcarrier spacing, resampling the unknown OFDM signal frame to generate a second sampled signal frame; In combination with the subcarrier spacing and the number of subcarriers, an improved maximum likelihood estimation method is used to recover the lost data segment from the second sampling signal frame to ensure high-accuracy data reconstruction.

3. The method according to claim 2, characterized in that The resampling process is performed on the unknown OFDM signal frame based on the number of subcarriers and the subcarrier spacing to generate a second sampled signal frame, including: Determine the product of the subcarrier spacing and the number of subcarriers as the actual sampling rate; Based on the actual sampling rate, the unknown OFDM signal frame is resampled to obtain a second sampled signal frame.

4. The method according to claim 3, characterized in that: When the service requirement also includes signal monitoring, identifying the frame structure parameters of the OFDM system corresponding to the service requirement of the receiving device according to the sampling point difference, and performing corresponding service processing according to the identified frame structure parameters, including: Calculate the CP length and the number of OFDM symbols of the unknown OFDM signal frame according to the position of the maximum peak and the position of the second largest peak, the amplitude of the maximum peak and the amplitude of the second largest peak, and the sampling point difference; or calculate the number of sampling points of the second sampling signal frame according to the sampling point difference, and calculate the CP length and the number of OFDM symbols according to the number of sampling points of the second sampling signal frame; Based on the CP length and the number of OFDM symbols, the real-time monitoring model is updated to determine the changing trend of the CP length and the number of OFDM symbols. A dynamic threshold early warning mechanism is set according to the changing trend to discover potential problems. The potential problems include: the spectrum efficiency drops to a preset efficiency threshold and the bit error rate rises to a preset bit error rate threshold. A distributed computing framework is introduced to accelerate the update process and the setting process.

5. The method according to claim 4, characterized in that The calculating the CP length and the number of OFDM symbols according to the number of sampling points of the second sampling signal frame includes: Calculating the difference between the number of sampling points and the number of subcarriers; According to the difference, intercepting a first sub-signal frame from the second sampling signal frame, and according to the number of sub-carriers and the number of sampling points, intercepting a second sub-signal frame; Performing a dot product on the first sub-signal frame and the second sub-signal frame to obtain a first intermediate signal frame; Using one quarter of the number of subcarriers as the length of a sliding window, and performing sliding addition on elements in the first intermediate signal frame according to the length of the sliding window to obtain a second intermediate signal frame; performing an absolute value operation on the second intermediate signal frame to obtain a third intermediate signal frame; Calculating position marker data corresponding to all peak values ​​in the third intermediate signal frame, and storing the position marker data corresponding to all peak values ​​in a first vector in chronological order; Differentiate the first vector to obtain the second vector; The mean value of the second vector is determined as the CP length, and the number of sampling points corresponding to the first vector is determined as the number of OFDM symbols.

6. The method according to claim 1, characterized in that When the service requirement is security analysis, identifying the frame structure parameters of the OFDM system corresponding to the service requirement of the receiving device according to the sampling point difference, and performing corresponding service processing according to the identified frame structure parameters, including: Analyzing whether an unknown OFDM signal frame has an abnormal pattern according to the sampling point difference; Based on the results of abnormal pattern analysis, machine learning algorithms are applied to identify potential security threat events; Based on the potential security threat events, quantum key distribution technology is used to build a secure communication link to ensure the integrity and confidentiality of data during transmission; Deploy smart contract automated response strategies, and when a potential security threat event is determined to be a real security threat event, execute defense measures corresponding to the type of real security threat event.

7. The method according to claim 1, characterized in that When the service requirement is network optimization, identifying the frame structure parameters of the OFDM system corresponding to the service requirement of the receiving device according to the sampling point difference, and performing corresponding service processing according to the identified frame structure parameters, including: Use the sampling point difference to perform preliminary analysis on the unknown OFDM signal frame and obtain the subcarrier spacing; According to the subcarrier spacing, the first sampled signal frames corresponding to different unknown OFDM signal frames in the unknown OFDM signal frame sequence are collected, and the network performance information to be optimized is found by using big data analysis technology; According to the network performance to be optimized information, dynamically adjusting the subcarrier spacing using a reinforcement learning algorithm to obtain an adjusted subcarrier spacing; Generate an adaptive coding scheme based on the adjusted subcarrier spacing to automatically select the optimal coding method under different network conditions; The software-defined network architecture is used to allocate resources to the receiving device according to the adaptive coding scheme.

8. A system for identifying unknown OFDM signal frame structure parameters, characterized in that: Receiving equipment used in OFDM systems includes: A receiving module, used for receiving an unknown orthogonal frequency division multiplexing OFDM signal frame sequence sent by a transmitting device in an OFDM system, and intercepting an unknown OFDM signal frame from the unknown OFDM signal frame sequence; A calculation resampling module, used for calculating the signal bandwidth of the unknown OFDM signal frame, taking the signal bandwidth as a known sampling rate, resampling the unknown OFDM signal frame to obtain a first sampled signal frame, and performing an autocorrelation operation on the first sampled signal frame according to a preset autocorrelation function to obtain an autocorrelation operation result; a detection and calculation module, configured to use the cyclic prefix CP of each OFDM symbol in the first sampling signal frame as a reference feature, perform peak detection on the autocorrelation operation result, determine the positions and amplitudes of all peaks, select the peak with the largest amplitude from all peaks as the maximum peak, select the peak with the second largest amplitude as the second largest peak, and calculate the sampling point difference between the maximum peak and the second largest peak according to the position of the maximum peak and the position of the second largest peak; An identification module is used to identify the frame structure parameters of the OFDM system corresponding to the service requirements of the receiving device according to the sampling point difference, and perform corresponding service processing according to the identified frame structure parameters; the frame structure parameters include at least one of the following: the number of subcarriers, the subcarrier spacing, the actual sampling rate, the CP length and the number of OFDM symbols.

9. A computing device, characterized in that It comprises a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to implement a method for identifying unknown OFDM signal frame structure parameters as described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a computer, a method for identifying unknown OFDM signal frame structure parameters as described in any one of claims 1 to 7 is implemented.

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