Frame header coarse positioning method, device, equipment and medium based on phase sliding window

Abstract

The present application relates to the technical field of digital signal processing, and in particular to a method, device, equipment and medium for coarse positioning of a frame header based on a phase sliding window. The present application first performs polar coordinate transformation on the feedback signal to calculate the phase quantity; then downsamples the phase quantity to reduce the amount of data; then uses a mean sliding window with a sliding window length of L to perform mean filtering on the downsampled phase quantity, calculates the mean of the phase quantity in the window, and eliminates the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity in the window; then delays the corrected mean data by half the length of the frame data to obtain the delayed phase quantity, compares the mean of the phase quantity in the window and the delayed phase quantity, and determines the middle position of the jump point; finally, calculates the starting point position of the frame header based on the middle position of the jump point and the amount of frame header data. The present application avoids complex complex multiplication operations, reduces hardware resource usage, can quickly complete coarse positioning, and improves the efficiency of the synchronization process.

Description

Technical Field

[0001] The present application relates to the technical field of digital signal processing, and in particular to a method, apparatus, device and medium for coarse positioning of a frame header based on a phase sliding window. Background Art

[0002] Digital terrestrial television broadcasting systems use high-power RF amplifiers. To improve the efficiency of the power amplifiers while meeting the requirements of the communication system, digital predistortion linearization technology is often used.

[0003] The key parameter calculation module within a digital pre-distortion system requires two signals, the forward and feedback signals. To fit the power amplifier model, synchronization is the first step. Although the feedback signal is distorted by the power amplifier, it still exhibits a strong correlation with the forward signal. Therefore, cross-correlation is often used to calculate the delay between the two signals.

[0004] However, in practical applications, the amount of resources required by the traditional complex cross-correlation module increases dramatically as the number of correlation points increases, and this situation needs to be further improved. Summary of the Invention

[0005] In order to solve the synchronization problem in the digital predistortion linearization technology in the digital terrestrial television broadcasting system, the present application provides a method, apparatus, device and medium for coarse frame header positioning based on a phase sliding window, which adopts the following technical solutions:

[0006] In a first aspect, the present application provides a frame header coarse positioning method based on a phase sliding window, comprising the following steps:

[0007] Perform polar coordinate transformation on the feedback signal to obtain the phase quantity ;

[0008] For the phase quantity Downsample to obtain the downsampled phase quantity ,in, is the sampling value according to the set downsampling multiple;

[0009] The downsampled phase quantity is processed by the mean sliding window with a sliding window length of L, and the mean of the phase quantity in the window is calculated. , and eliminate the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window;

[0010] The mean of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point;

[0011] The frame header starting point is calculated according to the middle position of the jump point and the amount N of frame header data.

[0012] By adopting the above technical solution, based on the inconsistent phase characteristics of the DTMB signal frame header and frame body, the IQ modulation method of the frame header makes its phase change only between two points, while the frame body adopts 4QAM / 16QAM / 64QAM and other modulation methods; the application first performs polar coordinate transformation on the feedback signal to calculate the phase quantity; then downsamples the phase quantity to reduce the data volume; then uses a mean sliding window with a sliding window length of L to perform mean filtering on the downsampled phase quantity, calculates the mean of the phase quantity within the window, and eliminates the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window; then, the corrected mean data is delayed by half the frame data length to obtain the delayed phase quantity, and the mean of the phase quantity within the window and the delayed phase quantity are compared to determine the middle position of the jump point; finally, the frame header starting point position is calculated based on the middle position of the jump point and the frame header data volume; complex complex multiplication operations are avoided, and hardware resource usage is greatly reduced; coarse positioning can be completed quickly, providing a good initial position for subsequent precise positioning, and improving the efficiency of the entire synchronization process.

[0013] Optionally, the downsampled phase quantity is calculated using the following formula:

[0014] ;

[0015] in, is the sampling value at time t according to the downsampling multiple, is the down-sampled feedback signal, and Respectively represent the real part and imaginary part, is the phase quantity after downsampling.

[0016] By adopting the above technical solution, the present application can accurately capture the phase characteristics of the signal through polar coordinate transformation, and the use of downsampling processing can significantly reduce the amount of data processing and the computational complexity while maintaining the main characteristics of the signal; providing reliable basic data for subsequent processing.

[0017] Optionally, the sliding window length L is an integer power of 2, and the corrected mean is calculated by the following formula during the sliding window process: :

[0018] ;

[0019] in, is the mean value of the phase quantity in the window, is the maximum value of the phase quantity in the window, is the minimum value of the phase quantity in the window, i represents the discrete sampling point index in the sliding window, and its value range is 1≤i≤L.

[0020] By adopting the above technical solution, this application uses integer powers of 2 as the sliding window length, which is convenient for implementation on hardware platforms such as FPGA. By removing the maximum and minimum values, the interference caused by the mutation points can be effectively reduced.

[0021] Optionally, the mean Delay half of the frame data to get the delayed phase amount , calculated using the following formula:

[0022] ;

[0023] Among them, F is the frame data length, is the delayed phase amount, Indicates delayed processing.

[0024] By adopting the above technical solution, the mean value is delayed by half of the frame data to obtain the delayed phase amount.

[0025] Optionally, the frame header data amount N is a fixed value, and the frame header mapping formula is as follows:

[0026] ,in, It is the modulation symbol of the frame header.

[0027] By adopting the above technical solution, the present application uses a fixed frame header mapping method to make the frame header have a unique phase feature, which is convenient for distinguishing from the frame body and improving positioning accuracy.

[0028] Optionally, the frame header starting point is calculated using the following formula:

[0029] , where P is the approximate position of the frame header starting point, Indicates the location of the calculation point, N is the amount of frame header data, is the mean value of the phase quantity in the window, is the delayed phase amount, Indicates the middle position of the trip point.

[0030] By adopting the above technical solution, the present application adopts the middle position of the jump point combined with the calculation method of the frame header data amount to accurately locate the starting position of the frame header, providing a reliable reference for subsequent precise positioning.

[0031] In a second aspect, the present application provides a frame header coarse positioning device based on a phase sliding window, comprising:

[0032] Phase conversion unit, used to perform polar coordinate transformation on the feedback signal to obtain the phase quantity ;

[0033] A downsampling unit for the phase quantity Downsample to obtain the downsampled phase quantity ,in is the sampling value according to the set downsampling multiple;

[0034] The sliding window processing unit is used to perform mean filtering on the downsampled phase quantity using a mean sliding window with a sliding window length of L, and calculate the mean of the phase quantity in the window. , and eliminate the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window;

[0035] The delay comparison unit is used to compare the average value of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point;

[0036] The positioning calculation module is used to calculate the frame header starting point according to the middle position of the jump point and the frame header data amount N.

[0037] In a third aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the above-mentioned phase sliding window-based frame header coarse positioning method are implemented.

[0038] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned phase sliding window-based frame header coarse positioning method.

[0039] In summary, this application includes at least one of the following beneficial technical effects:

[0040] The present application first performs polar coordinate transformation on the feedback signal to calculate the phase quantity; then downsamples the phase quantity to reduce the data volume; then uses a mean sliding window with a sliding window length of L to perform mean filtering on the downsampled phase quantity, calculates the mean of the phase quantity within the window, and eliminates the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window; then delays the corrected mean data by half the frame data length to obtain the delayed phase quantity, compares the mean of the phase quantity within the window with the delayed phase quantity, and determines the middle position of the jump point; finally, calculates the starting point position of the frame header based on the middle position of the jump point and the frame header data volume; avoids complex complex multiplication operations, greatly reduces hardware resource usage, can quickly complete coarse positioning, provides a good initial position for subsequent precise positioning, and improves the efficiency of the entire synchronization process;

[0041] This application can accurately capture the phase characteristics of the signal through polar coordinate transformation, and adopt downsampling processing to significantly reduce the amount of data processing and reduce the computational complexity while maintaining the main characteristics of the signal; providing reliable basic data for subsequent processing;

[0042] This application uses an integer power of 2 as the sliding window length, which is easy to implement on hardware platforms such as FPGA. By removing the maximum and minimum values, the interference caused by the mutation point can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a DTMB frame data phase diagram according to an embodiment of the present application;

[0044] Figure 2 This is a diagram showing the phase sliding window results of two frames of data in an embodiment of the present application;

[0045] Figure 3 This is a flow chart of a method for coarse frame header positioning based on a phase sliding window according to an embodiment of the present application;

[0046] Figure 4 This is a comparison diagram of delayed data and sliding window data in an embodiment of the present application;

[0047] Figure 5 This is a unit diagram of a frame header coarse positioning device based on a phase sliding window according to an embodiment of the present application;

[0048] Figure 6 This is a diagram of the internal structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0049] In this application, the following terms should be understood as follows: "Phase quantity" refers to the angle value obtained after converting the signal from a rectangular coordinate system to a polar coordinate system. "Downsampling" refers to a processing method of sampling the signal according to a specific sampling multiple to reduce the amount of data. "Sliding window" refers to a technical method of selecting a data segment of a certain length for processing and moving the processing window point by point during the signal processing process. "Frame header" and "frame body" refer to the preamble part and the valid data part of the data frame in the digital terrestrial television broadcasting system, respectively. "Mean filtering" refers to a processing method of calculating the average value of the data in the sliding window, which is used to suppress signal noise. "Delay comparison" refers to the operation of delaying a signal by a specific length and comparing it with the original signal.

[0050] Unless otherwise expressly indicated, the technical terms used in this application should be understood as having the common meanings known to those skilled in the art. Certain terms used in the specification and claims of this application are only used to accurately describe the specific embodiments of this application and should not be understood as limiting this application.

[0051] The embodiments of the present application are described in further detail below with reference to the accompanying drawings.

[0052] Since the phase characteristics of the DTMB signal frame header and frame body are inconsistent, the modulation characteristics of the same frame header IQ are as follows: Figure 1 As shown, the phase of the frame header changes only between two points. The frame body adopts 4QAM / 16QAM / 64QAM modulation, and the data phase sliding window results of the two frames of data are as follows: Figure 2 shown.

[0053] Therefore, based on the inconsistent phase characteristics of the DTMB signal frame header and frame body. In the first aspect, the present application provides a frame header coarse positioning method based on a phase sliding window, referring to Figure 3 , including the following steps:

[0054] S100: Perform polar coordinate transformation on the feedback signal to obtain a phase quantity.

[0055] Specifically, the system collects the ADC feedback signal, converts the complex domain data of the feedback signal into polar coordinate form through polar coordinate transformation, and extracts the phase characteristics of the signal. This transformation process eliminates the influence of signal amplitude information and retains the key phase characteristics.

[0056] S200: Downsample the phase quantity to obtain a downsampled phase quantity.

[0057] Specifically, is the sampling value according to the set downsampling multiple. In this embodiment, for example, 10 times downsampling is performed, assuming that the frame header mapping formula of a frame data is ,in, is the modulation symbol of the frame header. The phase quantity is downsampled, where is the sampling value at time t according to the downsampling multiple, is the down-sampled feedback signal, and Respectively represent the real part and imaginary part, is the phase quantity after downsampling. Downsampling significantly reduces the amount of subsequent calculations by reducing the data sampling rate while ensuring the key phase characteristics.

[0058] S300 , performing mean filtering on the downsampled phase quantity using a mean sliding window with a sliding window length of L, calculating the mean of the phase quantity within the window, and eliminating the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window.

[0059] Specifically, the sliding window length L is set to an integer power of 2 (such as L=2048), and the downsampled phase quantity is processed by sliding window. The mean of the phase quantity in the window is calculated by the following formula: : ,in, is the mean value of the phase quantity in the window, is the maximum value of the phase quantity in the window, is the minimum value of the phase quantity in the window, i represents the discrete sampling point index in the sliding window, and its value range is 1≤i≤L.

[0060] S400, the mean of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point.

[0061] Among them, the mean Delay half of the frame data to get the delayed phase amount , Calculated by the following formula: , F is the frame data length, is the delayed phase amount, Indicates delayed processing. Since the mean value of the frame header phase mapping is not equal to the mean value of the frame body phase mapping, there is a jump in the phase sum during the sliding window process, that is, when The position when is the middle position of the jump point. Figure 4 As shown, by comparing the delay data with the sliding window data, when the delay data and the sliding window data are the same and show a downward trend, the middle point position of the frame header, that is, the middle position of the jump point, can be determined.

[0062] S400: Calculate a frame header starting point according to a middle position of the jump point and a frame header data amount.

[0063] Specifically, the frame header starting point is calculated using the following formula: , where P is the approximate position of the frame header starting point, Indicates the location of the calculation point, N is the amount of frame header data, is the mean value of the phase quantity in the window, is the delayed phase amount, Indicates the middle position of the trip point.

[0064] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0065] In the second aspect, the present application provides a frame header coarse positioning device based on a phase sliding window. The frame header coarse positioning device based on a phase sliding window of the present application is described below in combination with the above-mentioned frame header coarse positioning method based on a phase sliding window.

[0066] Reference Figure 5 , a frame header coarse positioning device based on phase sliding window, comprising:

[0067] Phase conversion unit, used to perform polar coordinate transformation on the feedback signal to obtain the phase quantity ;

[0068] A downsampling unit for the phase quantity Downsample to obtain the downsampled phase quantity ,in is the sampling value according to the set downsampling multiple;

[0069] The sliding window processing unit is used to perform mean filtering on the downsampled phase quantity using a mean sliding window with a sliding window length of L, and calculate the mean of the phase quantity in the window. , and eliminate the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window;

[0070] The delay comparison unit is used to compare the average value of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point;

[0071] The positioning calculation module is used to calculate the frame header starting point according to the middle position of the jump point and the frame header data amount N.

[0072] In one embodiment, the present application provides an electronic device, which may be a server, and its internal structure diagram may be as follows: Figure 6 As shown. The electronic device includes a processor, a memory, and a network interface connected via a system bus. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the electronic device is used to store data. The network interface of the electronic device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a method for coarse frame header positioning based on a phase sliding window is implemented.

[0073] Those skilled in the art will understand that Figure 6The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the electronic device to which the solution of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0074] In one embodiment, an electronic device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0075] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The above-described computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the above-described method embodiments. Any reference to memory, storage, database, or other media used in the embodiments provided herein may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0076] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A frame header coarse positioning method based on phase sliding window, characterized in that: The steps include: Perform polar coordinate transformation on the feedback signal to obtain the phase quantity ; For the phase quantity Downsample to obtain the downsampled phase quantity ,in, is the sampling value according to the set downsampling multiple; The average sliding window with a sliding window length of L is used to perform mean filtering on the downsampled phase quantity, and the mean of the phase quantity in the window is calculated. , and eliminate the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window; The mean of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point; The frame header starting point is calculated according to the middle position of the jump point and the amount N of frame header data.

2. The frame header coarse positioning method based on phase sliding window according to claim 1, characterized in that: The downsampled phase quantity is calculated by the following formula: ； in, is the sampling value at time t according to the downsampling multiple, is the down-sampled feedback signal, and Respectively represent the real part and imaginary part, is the phase quantity after downsampling.

3. The frame header coarse positioning method based on phase sliding window according to claim 1, characterized in that: The sliding window length L is an integer power of 2, and the corrected mean is calculated by the following formula during the sliding window process: : ； in, is the mean value of the phase quantity in the window, is the maximum value of the phase quantity in the window, is the minimum value of the phase quantity in the window, i represents the discrete sampling point index in the sliding window, and its value range is 1≤i≤L.

4. The method for coarse frame header positioning based on phase sliding window according to claim 3, characterized in that: The mean Delay half of the frame data to get the delayed phase amount , calculated using the following formula: ； Among them, F is the frame data length, is the delayed phase amount, Indicates delayed processing.

5. The frame header coarse positioning method based on phase sliding window according to claim 2, characterized in that: The frame header mapping formula is as follows: ,in, is the modulation symbol of the frame header, i represents the imaginary unit, .

6. The method for coarse frame header positioning based on phase sliding window according to claim 1, characterized in that: The frame header starting point is calculated using the following formula: , where P is the approximate position of the frame header starting point, Indicates the location of the calculation point, N is the amount of frame header data, is the mean value of the phase quantity in the window, is the delayed phase amount, Indicates the middle position of the trip point.

7. A frame header coarse positioning device based on phase sliding window, characterized in that: include: Phase conversion unit, used to perform polar coordinate transformation on the feedback signal to obtain the phase quantity ; A downsampling unit for the phase quantity Downsample to obtain the downsampled phase quantity ,in is the sampling value according to the set downsampling multiple; The sliding window processing unit is used to perform mean filtering on the downsampled phase quantity using a mean sliding window with a sliding window length of L, and calculate the mean of the phase quantity in the window. , and eliminate the mutation point error by subtracting the maximum and minimum values ​​of the phase quantity within the window; The delay comparison unit is used to compare the average value of the phase quantity in the window Delay half of the frame data to get the delayed phase amount , compare the mean of the phase quantity in the window and the delay phase amount , determine the middle position of the jump point; The positioning calculation module is used to calculate the frame header starting point according to the middle position of the jump point and the frame header data amount N.

8. An electronic device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the frame header coarse positioning method based on a phase sliding window according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the frame header coarse positioning method based on a phase sliding window are implemented as described in any one of claims 1 to 6.

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