DVB-s2 burst signal large doppler frequency offset estimation method and electronic equipment

Abstract

The application provides a DVB-S2 burst signal large Doppler frequency offset estimation method and electronic equipment, and the method comprises the following steps: based on the starting domain information of a frame header in a target DVB-S2 burst signal, a first frequency offset estimation result is obtained through an L&R frequency offset estimation algorithm based on prior value compensation; the physical layer signaling domain information of the last L1 symbols of the frame header is decoded through Reed-Muller code decoding; based on the starting domain information and the physical layer signaling domain information, a second frequency offset estimation result is obtained; all pilot block information is obtained, and a third frequency offset estimation result is obtained through coherent accumulation and fast Fourier transform; based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, a large Doppler frequency offset estimation result of the DVB-S2 burst signal is obtained. Through the above three-step fine estimation algorithm, accurate and simple large Doppler frequency offset estimation of the DVB-S2 burst signal is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computer, in particular to a DVB-S2 burst signal large Doppler frequency offset estimation method and electronic equipment. BACKGROUND

[0002] In a wireless digital communication system, due to various factors, such as Doppler shift, multipath fading and local oscillator instability, etc., the signal loss is caused, so that the carrier is difficult to synchronize. Among these losses, the most influential factor on the receiving performance is the frequency offset. The frequency offset in signal transmission will cause the interference between carriers, thereby leading to the performance decline, and in severe cases, it will lead to the original information cannot be demodulated. In order to correctly demodulate the signal, the carrier frequency must be estimated with high precision, so that the system achieves good carrier synchronization.

[0003] At present, many solutions have been proposed for frequency offset estimation at home and abroad. One of the solutions is based on the amplitude angle of the autocorrelation function, such as Fitz algorithm or L&R algorithm, and then the frequency offset estimation result is obtained. This kind of solution has very low signal-to-noise ratio threshold. Another solution is to find the maximum value by taking the modulus of the FFT sequence, such as the DA synchronization algorithm based on FFT, so as to obtain the frequency offset estimation result. This solution uses all the pilot symbols and data symbols information in the received signal, and has high frequency offset estimation accuracy.

[0004] However, the frequency offset estimation method based on the amplitude angle of the autocorrelation function has a very narrow frequency offset estimation range, and the estimation accuracy is poor under the condition of large Doppler frequency offset. When using the FFT sequence for frequency offset estimation, the DA synchronization algorithm currently used needs to use all the pilot and data symbols. For DVB-S2 system with long code length, the complexity is too high when reaching the target performance. Therefore, the above two solutions are not suitable for the large Doppler frequency offset estimation of DVB-S2 burst signal. SUMMARY

[0005] The present application provides a DVB-S2 burst signal large Doppler frequency offset estimation method and electronic equipment to solve the defects of the prior art, such as the inability to be applied to the large Doppler frequency offset estimation of DVB-S2 burst signal, and to achieve the goal of accurately and simply estimating the large Doppler frequency offset of DVB-S2 burst signal.

[0006] The present application provides a DVB-S2 burst signal large Doppler frequency offset estimation method, comprising:

[0007] Based on the starting domain information of the frame header in the target DVB-S2 burst signal, the first frequency offset estimation result of the target DVB-S2 burst signal is calculated by using the L&R frequency offset estimation algorithm based on the prior value compensation;

[0008] decoding the Reed-Muller code, the physical layer signaling field information of the L1 symbols after the frame header in the target DVB-S2 burst signal is decoded;

[0009] Based on the starting field information and the L1 physical layer signaling field information, a second frequency offset estimation result of the target DVB-S2 burst signal is obtained through a frequency domain algorithm;

[0010] All pilot block information of the target DVB-S2 burst signal is obtained, and a third frequency offset estimation result of the target DVB-S2 burst signal is obtained through coherent accumulation and fast Fourier transform on the all pilot block information;

[0011] Based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, a large Doppler frequency offset estimation result of the target DVB-S2 burst signal is obtained.

[0012] According to the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the application, the first frequency offset estimation result of the target DVB-S2 burst signal is obtained through the L&R frequency offset estimation algorithm based on the prior value compensation, which comprises:

[0013] The frame header of the target DVB-S2 burst signal is extracted, and the first carrier is obtained through data stripping of the frame header;

[0014] The first carrier is subjected to autocorrelation operation, and the average autocorrelation noise reduction formula is obtained through average operation and smoothing operation on the autocorrelation result;

[0015] Based on the average autocorrelation noise reduction formula, the first frequency offset estimation result is obtained through the first formula derived from the equal ratio series summation formula and the Euler formula according to the average autocorrelation noise reduction formula.

[0016] According to the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the application, the second frequency offset estimation result of the target DVB-S2 burst signal is obtained through the frequency domain algorithm, which comprises:

[0017] Based on the starting field information and the L1 physical layer signaling field information, the frame header information subjected to the prior value compensation is subjected to data stripping to obtain the second carrier;

[0018] The second carrier is subjected to frequency domain estimation operation to obtain the second frequency offset estimation result.

[0019] The method comprises the following steps: acquiring a target DVB-S2 burst signal; acquiring a first frequency offset estimation result of the target DVB-S2 burst signal based on a start domain information of a frame header in the target DVB-S2 burst signal; acquiring a second frequency offset estimation result of the target DVB-S2 burst signal based on a first frequency offset estimation result and a second frequency offset estimation result; and acquiring a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and a Doppler frequency offset coarse estimation result captured max ;

[0020] Correspondingly,

[0021] The method further comprises the following steps:

[0022] Based on k max , a left adjacent point k l and a right adjacent point k r , an approximate value of a parabola function is derived as follows:

[0023]

[0024] Based on the approximate value Δk, a corrected position index k is acquired, and a corrected second frequency offset estimation result is acquired by substituting the corrected position index k into the second frequency offset estimation result.

[0025] The method comprises the following steps: acquiring a target DVB-S2 burst signal; acquiring a first frequency offset estimation result of the target DVB-S2 burst signal based on a start domain information of a frame header in the target DVB-S2 burst signal; acquiring a second frequency offset estimation result of the target DVB-S2 burst signal based on a first frequency offset estimation result and a second frequency offset estimation result; and acquiring a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and a Doppler frequency offset coarse estimation result captured

[0026] The reference waveform of the whole pilot block information is utilized to realize data stripping of the frame header by performing coherent accumulation on the whole pilot block information;

[0027] Fast Fourier transform is performed on the data stripping result, and the third frequency offset estimation result is acquired based on the result of the fast Fourier transform.

[0028] The method comprises the following steps: acquiring a target DVB-S2 burst signal; acquiring a first frequency offset estimation result of the target DVB-S2 burst signal based on a start domain information of a frame header in the target DVB-S2 burst signal; acquiring a second frequency offset estimation result of the target DVB-S2 burst signal based on a first frequency offset estimation result and a second frequency offset estimation result; and acquiring a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and a Doppler frequency offset coarse estimation result captured

[0029] The first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result are superimposed, and a large Doppler frequency offset estimation result is calculated and acquired in combination with a Doppler frequency offset coarse estimation result F d captured.

[0030] The application further provides a DVB-S2 burst signal large Doppler frequency offset estimation device, comprising:

[0031] A first processing module is configured to acquire a first frequency offset estimation result of a target DVB-S2 burst signal based on a start domain information of a frame header in the target DVB-S2 burst signal by using a L&R frequency offset estimation algorithm based on a prior value compensation.

[0032] a second processing module, configured to decode the physical layer signaling field information of the L1 symbols after the frame header in the target DVB-S2 burst signal by Reed-Muller code decoding;

[0033] a third processing module, configured to acquire a second frequency offset estimation result of the target DVB-S2 burst signal by a frequency domain algorithm based on the starting field information and the L1 pieces of physical layer signaling field information;

[0034] a fourth processing module, configured to acquire all pilot block information of the target DVB-S2 burst signal, and acquire a third frequency offset estimation result of the target DVB-S2 burst signal by coherent accumulation and fast Fourier transform on the all pilot block information;

[0035] an operation output module, configured to acquire a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

[0036] The application further provides an electronic device, including a memory, a processor and a program or instructions stored on the memory and executable on the processor, when the processor executes the program or instructions, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method are implemented.

[0037] The application further provides a non-transitory computer readable storage medium, which stores a program or instructions, when the program or instructions are executed by a computer, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method are implemented.

[0038] The application further provides a computer program product, which includes a computer program stored on a non-transitory computer readable storage medium, the computer program includes program instructions, when the program instructions are executed by a computer, the computer can execute the DVB-S2 burst signal large Doppler frequency offset estimation method.

[0039] The DVB-S2 burst signal large Doppler frequency offset estimation method and the electronic device provided by the application first perform the first step L&R algorithm accurate estimation by using the frame header starting field information, then further estimate the frequency offset by using the frequency domain algorithm based on the Reed-Muller code decoded physical layer signaling field information and the starting field information and all frame header information, finally perform accurate estimation by using coherent accumulation and fast Fourier transform on all known pilot block information, and finally realize accurate and simple large Doppler frequency offset estimation of the DVB-S2 burst signal. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments of the present application or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0041] Figure 1 The flowchart of the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application is shown in the figure.

[0042] Figure 2 The structure diagram of the DVB-S2 burst signal frame in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application is shown in the figure.

[0043] Figure 3 The flowchart of obtaining the first frequency offset estimation result in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application is shown in the figure.

[0044] Figure 4 The framework diagram of the coherent accumulation of all pilot block information in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application is shown in the figure.

[0045] Figure 5 The structure diagram of the DVB-S2 burst signal large Doppler frequency offset estimation device provided by the present application is shown in the figure.

[0046] Figure 6 The physical structure diagram of the electronic device provided by the present application is shown in the figure. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described clearly and completely in the following with reference to the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0048] The present application aims at the problems of the prior art that cannot be applied to the large Doppler frequency offset estimation of DVB-S2 burst signals. The first step of L&R algorithm is performed by using the start field information of the frame header. Then, the frequency offset is further estimated by using the frequency domain algorithm based on the physical layer signaling field information and the start field information decoded by Reed-Muller code and all frame header information. Finally, the precise estimation is performed by using all known pilot block information through coherent accumulation and fast Fourier transform, so that the precise and simple large Doppler frequency offset estimation of DVB-S2 burst signals is realized. The present application will be described and introduced in detail through multiple embodiments in combination with the drawings.

[0049] Figure 1 The flowchart of the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application is shown in Figure 1 , which comprises the following steps.

[0050] In S101, the first frequency offset estimation result of the target DVB-S2 burst signal is calculated by using the L&R frequency offset estimation algorithm based on the prior value compensation based on the start field information of the frame header in the target DVB-S2 burst signal.

[0051] It can be understood that the structure of the DVB-S2 burst frame in the present application is shown in Figure 2 , which is the structure diagram of the DVB-S2 burst signal frame in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application. Each physical frame of the DVB-S2 burst signal comprises a frame header with a length of H symbols and a frame body with a variable length, and the frame body is composed of data symbols and pilot blocks inserted at equal intervals.

[0052] The start field length of the frame is L0 symbols, which can be used for frame synchronization process. A pilot block with a length of S known symbols is inserted every D data symbols in the frame body, and the tail of each physical frame has no pilot block. The pilot can be used for frequency offset estimation. The physical frame parameters in the DVB-S2 protocol are shown in Table 1, which is the physical frame parameter table of the DVB-S2 burst signal in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application. In order to facilitate the description, the following eight different modulation modes and waveforms with different lengths are respectively assigned with waveform IDs 1-8 in the present application.

[0053] Table 1, the physical frame parameter table of the DVB-S2 burst signal in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the present application

[0054]

[0055] For the frame structure of DVB-S2 / DVB-S2X, the burst signal is long, and the frame structure contains multiple pilot blocks with a length of S known symbols. In order to make full use of the frame header and pilot information, the application first uses the frame header start domain information of the target DVB-S2 burst signal to perform initial estimation of the first step L&R algorithm. That is, since the frame header length is known, the frame header start position estimated at the frame synchronization time can be used to extract the frame header part of the received signal, and after further compensation according to the Doppler prior value, the L&R frequency offset estimation algorithm is operated to obtain the first frequency offset estimation result of the target DVB-S2 burst signal.

[0056] S102, the Reed-Muller code decoding is performed to decode the physical layer signaling domain information of the last L1 symbols of the frame header in the target DVB-S2 burst signal.

[0057] As can be understood from the above description, the frame header in the DVB-S2 burst signal includes the first L0 start domain and the last L1 symbols, and after the first frequency offset estimation result estimated in step S101 is compensated, the Reed-Muller code decoding of the error control coding technology can be performed. The Reed-Muller code decoding part decodes the physical layer signaling domain information of the L1 symbols in the frame header.

[0058] S103, based on the start domain information and the L1 physical layer signaling domain information, a second frequency offset estimation result of the target DVB-S2 burst signal is obtained by a frequency domain algorithm.

[0059] As can be understood, based on the above steps, the entire frame header information of all H (H=L0+L1) symbols can be obtained. Based on the entire frame header information, that is, the entire start domain information and the L1 physical layer signaling domain information, the frame header information after the first step of preliminary estimation and compensation can be stripped of data, and a second frequency offset estimation result can be obtained by using a frequency domain estimation algorithm.

[0060] That is, based on the start domain information obtained according to the above steps and the physical layer signaling domain information obtained by Reed-Muller code decoding, a frequency offset can be further estimated by a frequency domain algorithm based on the entire frame header information to obtain a second frequency offset estimation result.

[0061] S104, all pilot block information of the target DVB-S2 burst signal is obtained, and a third frequency offset estimation result of the target DVB-S2 burst signal is obtained by performing coherent accumulation and fast Fourier transform on the entire pilot block information.

[0062] It can be understood that, when the pilot information is subjected to frequency domain algorithm fine estimation, the coherent accumulation idea is considered. The accumulation mode is to take out all pilot blocks, respectively perform coherent accumulation on S symbol points of each pilot block, make the mutual cancellation of zero mean Gaussian white noise, thereby improving the signal-to-noise ratio, and meanwhile, less FFT point number can be used for frequency offset estimation, and the calculation complexity is reduced. On the basis of the coherent accumulation, the fast Fourier transform is performed, and according to the transform result, the third step estimation is performed, and the third frequency offset estimation result is obtained.

[0063] S105, based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, obtaining a large Doppler frequency offset estimation result of the target DVB-S2 burst signal.

[0064] It can be understood that, on the basis of obtaining three-step preliminary estimation, respectively obtaining the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, the comprehensive operation can be performed according to the preliminary estimation results, and the final estimation result is determined as the final large Doppler frequency offset estimation result of the target DVB-S2 burst signal. The comprehensive operation may, for example, be direct superposition or weighting, and the application does not limit this.

[0065] The DVB-S2 burst signal large Doppler frequency offset estimation method provided by the application estimates the frequency offset through the first step L&R algorithm fine estimation using the frame header start domain information; further estimates the frequency offset through the frequency domain algorithm based on the Reed-Muller code decoded physical layer signaling domain information and the start domain information and using all frame header information; finally, the fine estimation is performed through coherent accumulation and fast Fourier transform using all known pilot block information, and finally, the accurate and simple large Doppler frequency offset estimation of the DVB-S2 burst signal is realized.

[0066] According to the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the above embodiments, optionally, the step of calculating and obtaining the first frequency offset estimation result of the target DVB-S2 burst signal through the L&R frequency offset estimation algorithm based on the prior value compensation is as shown in the following Figure 3 The flowchart for obtaining the first frequency offset estimation result in the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the application is shown in the following

[0067] S301, extracting the frame header of the target DVB-S2 burst signal, and performing data stripping on the frame header to obtain a first carrier.

[0068] It can be understood that, in the application, since the frame header length is known, the frame header part of the received signal can be extracted according to the estimated frame header start position at the frame synchronization, and compensation is performed according to the Doppler prior value, that is:

[0069]

[0070] where s L (n) represents the extracted frame header part, F d represents the Doppler prior value, s L1 (n) represents s L (n) is the signal after Doppler coarse compensation.

[0071] After that, the obtained s L (n) is subjected to data stripping to obtain the first carrier as follows:

[0072]

[0073] where s head (n) represents the frame header frame start field baseband reference waveform, f d1 represents the frequency offset after prior compensation, w(n) represents zero-mean Gaussian white noise, and the superscript * represents the conjugate operation.

[0074] S302, autocorrelation operation is performed on the first carrier, and smoothing operation is performed by averaging the autocorrelation result to obtain an average autocorrelation noise reduction formula.

[0075] It can be understood that, on the basis of the first carrier set obtained according to the above steps, autocorrelation operation can be performed thereon according to the following formula:

[0076]

[0077] where L 0表示 The length of the frame start field of the original frame header is L0, and the total length of the frame header is H symbols, wherein the frame start field part of the first L0 symbols is known, and the physical layer signaling field information of the last L1 symbols needs to be obtained after Reed-Muller code decoding.

[0078] Therefore, formula (3) can be substituted into formula (2) to obtain the autocorrelation result as follows:

[0079]

[0080] After that, for the autocorrelation result, the influence of noise is smoothed by averaging to obtain:

[0081]

[0082] Assuming that the influence of the zero-mean noise term w'(m) on the above formula is not large, the average autocorrelation noise reduction formula can be obtained as follows:

[0083]

[0084] S303, based on the average autocorrelation noise reduction formula, and according to the average autocorrelation noise reduction formula, the first formula derived by the sum of the equal ratio sequence formula and the Euler formula, the first frequency offset estimation result is calculated and obtained.

[0085] It can be understood that, for the above-mentioned average autocorrelation noise reduction formula, the equal ratio sequence sum formula and the Euler formula can be used for derivation operation, and it can be verified that after the prior value compensation in the above-mentioned embodiment step S101, the frequency offset can satisfy the range condition The following equation is obtained:

[0086]

[0087] The condition for the above formula to be true is that the right side Must be a positive number, so This is consistent with the requirement that the range of the frequency offset is

[0088] When the L&R fine estimation is based on the frame start domain.

[0089] Then, the amplitude angle of both sides of formula (7) is taken, and formula (6) is brought in, to obtain the frequency offset estimation result of the first step estimation, that is, the first frequency offset estimation result:

[0090]

[0091] Since the amplitude angle is in the interval of -π to π, there is This is consistent with the frequency offset range of formula (7), and the frequency offset after the rough compensation satisfies this requirement.

[0092] According to the DVB-S2 burst signal large Doppler frequency offset estimation method provided in the above-mentioned embodiments, the second frequency offset estimation result of the target DVB-S2 burst signal is obtained by a frequency domain algorithm, which comprises: based on the start domain information and L1 physical layer signaling domain information, the frame header information after the prior value compensation is data stripped to obtain a second carrier; the second carrier is subjected to frequency domain estimation operation to obtain the second frequency offset estimation result.

[0093] It can be understood that, after the first step preliminary estimation of the frequency offset is compensated according to the above-mentioned embodiments, the Reed-Muller code decoding is performed, and the Reed-Muller code decoding part is to decode the content of the physical layer signaling domain part of the L1 symbols in the frame header. Thus, the whole frame header information of the H symbols in the frame header can be obtained. Then, the first step preliminary compensation frame header information is data stripped by using the whole frame header information, and the second step fine estimation of the frequency offset, that is, the second frequency offset estimation result is obtained by using the frequency domain estimation algorithm for:

[0094]

[0095] In the formula, k max This indicates the position with the largest peak value of the Fourier spectrum magnitude, and N represents the number of Fourier transform points. The number of FFT points should be greater than the total length of the frame header. In the DVB-S2 protocol, H is 90 symbols, so N in this invention can be 128.

[0096] Optionally, in the DVB-S2 burst signal Doppler frequency offset estimation method provided in the above embodiments, the frequency domain estimation operation includes a Fourier transform operation, and the position of the maximum peak value of the spectral magnitude of the Fourier transform operation result is k. max .

[0097] Accordingly, the DVB-S2 burst signal Doppler frequency offset estimation method provided by the above embodiments of the present invention further includes:

[0098] Based on k max left neighbor k l and right neighbor k r The approximate value of the parabola function is derived as follows:

[0099]

[0100] Based on the approximation value Δk, obtain the corrected position index. And by indexing the corrected position Substitute the second frequency offset estimation result into the equation to obtain the corrected second frequency offset estimation result.

[0101] This invention can be understood as follows: to further correct frequency shifts and make the results more accurate, the present invention considers utilizing the maximum value position index k in the Fast Fourier Transform. max left neighbor k l and right neighbor k r And it is used to derive an approximation of the parabola function as follows:

[0102]

[0103] Therefore, the corrected position index It can be represented as:

[0104]

[0105] After that, Replace k max Substitute into the second frequency offset estimation result From the frequency offset estimation formula, the corrected frequency offset estimate can be obtained, which is the corrected second frequency offset estimate.

[0106] Optionally, in the DVB-S2 burst signal Doppler frequency offset estimation method provided by the above embodiments, obtaining the third frequency offset estimation result of the target DVB-S2 burst signal includes: using the reference waveform of all pilot block information, performing coherent accumulation on all pilot block information to strip the data of the frame header; performing a fast Fourier transform on the data stripping result, and obtaining the third frequency offset estimation result based on the result of the fast Fourier transform.

[0107] This can be understood as the invention employing the concept of coherent accumulation when performing frequency domain algorithmic estimation of pilot information. For example... Figure 4 The diagram shown is a schematic representation of the framework for coherently accumulating all pilot block information in the DVB-S2 burst signal Doppler frequency offset estimation method provided by the present invention.

[0108] Since the preliminary estimations in steps S101 and S102 of the above embodiments have been performed, the root mean square error of the Doppler frequency offset can be reduced to a certain value. Furthermore, since only pilot block information is accumulated, which is equivalent to all data block information being zero, the accumulation period of the pilot is set to D+S symbols (one data part of D symbols plus one pilot part of S symbols) in the third fine estimation.

[0109] In the DVB-S2 protocol, a data block has 1440 symbols, and a pilot block has 36 symbols. After compensating for the frequency offset in step S101 according to the above embodiments, the information s(n) of each pilot block is extracted, and the known pilot block reference waveform c is used. PSam The data stripping of s(n) is performed as follows:

[0110]

[0111] Therefore, the frequency offset of the third fine-tuning step can be obtained, that is, the result of the third frequency offset estimation. for:

[0112]

[0113] In the formula, k max L represents the position where the peak value of the Fourier spectrum is the largest. coh The cumulative number of points is equal to the cumulative period D+S, and N represents the number of Fourier transform points, which is an integer power greater than the number of pilot blocks + D.

[0114] Referring to the above embodiments, the maximum value position index k can also be considered. max left neighbor k l and right neighbor k r The corrected position index is obtained using formulas (10) and (11). and replace k with it max into the frequency offset estimation formula of , the third frequency offset estimation result after correction can be obtained.

[0115] Wherein, according to the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the above embodiments, the acquisition of the large Doppler frequency offset estimation result of the target DVB-S2 burst signal comprises: superimposing the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, and combining the captured large Doppler frequency offset coarse estimation result F d , to calculate and acquire the large Doppler frequency offset estimation result.

[0116] It can be understood that the present application considers the simplest case, directly superimposes the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result calculated according to the above embodiments, and considers F d , to obtain the final estimation result f d of the large Doppler frequency offset of the target DVB-S2 burst signal as follows:

[0117]

[0118] In the formula, F d represents the captured large Doppler frequency offset coarse estimation result, represents the first frequency offset estimation result, represents the second frequency offset estimation result, represents the third frequency offset estimation result, and f d represents the final large Doppler frequency offset estimation result.

[0119] In order to further illustrate the technical scheme of the present application, the present application is described in more detail in the following embodiments, but the scope of protection of the present application is not limited.

[0120] The present application mainly faces the physical frame structure of DVB-S2 / DVB-S2X system burst signal, and proposes a large Doppler frequency offset estimation method, which is mainly divided into three steps, and specifically comprises the following steps:

[0121] First, time domain L&R fine estimation based on frame header start domain information. Specifically:

[0122] First, the estimated frame header start position is obtained through frame synchronization, and the frame header part of the received signal is extracted and compensated according to the Doppler prior value F d ;

[0123] Secondly, the obtained compensated signal is data-stripped to obtain a carrier, and the carrier is autocorrelated to obtain

[0124]

[0125] Thirdly, the average value is obtained to smooth the influence of noise, assuming that the influence of zero-mean noise term w'(m) is small, ignoring the noise term and considering the equation:

[0126]

[0127] The condition for its establishment is that the right side Must be a positive number, so Therefore, the range of frequency offset required in the L&R fine estimation based on the frame start domain is After compensation by the prior value, it can be ensured that the frequency offset meets this range condition;

[0128] Finally, by taking the amplitude angle of both sides, the frequency offset estimation result of the first step estimation is obtained as:

[0129]

[0130] Second step, frequency domain fine estimation based on all frame header information. Specifically, it includes:

[0131] Firstly, after compensating the frequency offset of the first step fine estimation, Reed-Muller code decoding is needed, and the Reed-Muller code decoding part is to decode the content of the physical layer signaling domain part of the long L1 symbols in the frame header, thereby obtaining all the frame header information of all H symbols;

[0132] Secondly, the data-stripped frame header information after the first step fine estimation compensation is used to obtain the frequency offset of the second step fine estimation by using the frequency domain estimation algorithm For:

[0133]

[0134] Wherein, k max is the position of the maximum Fourier spectrum modulus value, N is the Fourier transform point number, and the FFT point number is greater than the total length of the frame header;

[0135] Finally, in order to correct the frequency offset, the left adjacent point k l and the right adjacent point k r of the maximum value position index k max can be used to derive the approximate value of the parabolic function:

[0136]

[0137] The corrected position index is Substitute it into the frequency offset estimation formula of to obtain the corrected frequency offset estimation value.

[0138] The third step is the frequency offset fine estimation based on all pilot information, specifically including:

[0139] First, after the fine compensation of the second step, the information s(n) of each pilot block part is taken out, and the known pilot block reference waveform is used to perform data stripping on s(n);

[0140] Second, the frequency offset of the third step fine estimation is obtained, and the left adjacent point k l and the right adjacent point k r of the maximum value position index k max are also considered, the corrected position index k is used instead of k max , and substituted into the frequency offset estimation formula of to obtain the corrected frequency offset estimation;

[0141] Finally, the final Doppler frequency offset estimation value is:

[0142] The coherent accumulation method is used in the third step fine estimation of the embodiment of the application, that is, all pilot blocks are taken out, and S symbol points of each pilot block are respectively coherently accumulated, so that the zero mean Gaussian white noise is mutually offset, thereby improving the signal-to-noise ratio; at the same time, this method can also use fewer FFT points for frequency offset estimation, thereby reducing the calculation complexity.

[0143] In order to verify the actual effect of the application, a large number of tests are carried out on the embodiment of the application, and the results show that the maximum Doppler range that can be estimated by the method of the application is 20% symbol rate offset, and the frequency offset is estimated by fully utilizing the start domain information of the frame header, all frame header information and all pilot information. First, an frequency offset estimation value is obtained by using the L&R algorithm, and then the frame header and the pilot are processed by FFT, and finally the accurate frequency offset estimation result is obtained through three-step estimation and compensation.

[0144] Since the signal-to-noise ratio threshold of the L&R algorithm is low, an frequency offset compensation value can be obtained first, which is used for subsequent further FFT fine estimation. Compared with directly performing FFT estimation on the prior value, the estimation accuracy is improved. Since the physical frame header of DVB-S2 / DVB-S2X is very short, the complexity of the first two steps of estimation is not high, and at the same time, the FFT point number is reduced by superimposing the pilot in the third step estimation, thereby greatly reducing the complexity.

[0145] Taking DVB-S2 as an example, the first step L&R algorithm estimates the start field information of the frame header, and the complexity is O(n2), wherein n is the length of the start field of the frame / 2, and the length is fixed as 36; the second step is to perform FFT estimation on the whole frame header information, and the complexity is O(N*log2N), wherein N is the FFT point number greater than the length of the frame header, and the point number is fixed as 128; the third step is to perform coherent accumulation on the pilot block symbol (length 36) and the data symbol (length 1440, all taking 0), and the complexity is O(N*log2N), wherein N is the point number for FFT, and an appropriate value greater than the number of pilot blocks + 1440 is taken. In comparison, the DA method based on FFT needs to process all pilot symbols and data symbol information, and the complexity is O(N*log2N), wherein N is the point number for FFT, and different values are taken according to different waveforms and modulation modes. Taking waveform 9 and 8PSK modulation as an example, the total length is 22104, and the complexity of the three-step fine estimation method is about 7.4% of that of the DA method.

[0146] Based on the same inventive concept, the present application further provides a DVB-S2 burst signal large Doppler frequency offset estimation device according to the above-mentioned embodiments, which is used to estimate the DVB-S2 burst signal large Doppler frequency offset in the above-mentioned embodiments. Therefore, the description and definition in the DVB-S2 burst signal large Doppler frequency offset estimation method of the above-mentioned embodiments can be used for the understanding of each execution module in the present application, and specific reference can be made to the above-mentioned method embodiments, which will not be repeated here.

[0147] According to an embodiment of the present application, the structure of the DVB-S2 burst signal large Doppler frequency offset estimation device is shown in Figure 5 The structure of the DVB-S2 burst signal large Doppler frequency offset estimation device provided by the present application is shown in the structure diagram of the device, which can be used to realize the DVB-S2 burst signal large Doppler frequency offset estimation in the above-mentioned method embodiments, and the device comprises a first processing module 501, a second processing module 502, a third processing module 503, a fourth processing module 504 and an operation output module 505. Wherein:

[0148] The first processing module 501 is configured to calculate a first frequency offset estimation result of the target DVB-S2 burst signal based on start field information of a frame header in the target DVB-S2 burst signal by using an L&R frequency offset estimation algorithm based on prior value compensation; the second processing module 502 is configured to decode the physical layer signaling field information of the last L1 symbols of the frame header in the target DVB-S2 burst signal by using Reed-Muller code decoding; the third processing module 503 is configured to obtain a second frequency offset estimation result of the target DVB-S2 burst signal based on the start field information and the L1 pieces of physical layer signaling field information by using a frequency domain algorithm; the fourth processing module 504 is configured to obtain all pilot block information of the target DVB-S2 burst signal, and obtain a third frequency offset estimation result of the target DVB-S2 burst signal by using coherent accumulation and fast Fourier transform on the all pilot block information; and the operation output module 505 is configured to obtain a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

[0149] The DVB-S2 burst signal large Doppler frequency offset estimation device provided by the application can be used for accurate and simple large Doppler frequency offset estimation of a DVB-S2 burst signal.

[0150] Optionally, the first processing module, when used for calculating the first frequency offset estimation result of the target DVB-S2 burst signal by using the L&R frequency offset estimation algorithm based on prior value compensation, is configured to:

[0151] extract the frame header of the target DVB-S2 burst signal, and perform data stripping on the frame header to obtain a first carrier;

[0152] perform autocorrelation operation on the first carrier, and perform smoothing operation by averaging the autocorrelation result to obtain an average autocorrelation noise reduction formula;

[0153] the first frequency offset estimation result is calculated based on the average autocorrelation noise reduction formula and a first formula derived from a geometric progression summation formula and an Euler formula according to the average autocorrelation noise reduction formula.

[0154] Optionally, the second processing module, when used for obtaining the second frequency offset estimation result of the target DVB-S2 burst signal by using the frequency domain algorithm, is configured to:

[0155] Based on the starting domain information and the L1 physical layer signaling domain information, data stripping is performed on the frame header information compensated by the priori value to obtain a second carrier;

[0156] A frequency domain estimation operation is performed on the second carrier to obtain the second frequency offset estimation result.

[0157] Optionally, the frequency domain estimation operation includes a Fourier transform operation, and a maximum position of a spectrum modulus value of a result of the Fourier transform operation is k max ;

[0158] Correspondingly, the second processing module is further configured to:

[0159] Based on left and right neighboring points k max and k l of k r , an approximate value of a parabola function is derived as:

[0160]

[0161] Based on the approximate value △k, a corrected position index k is obtained, and the corrected position index k is substituted into the second frequency offset estimation result to obtain a corrected second frequency offset estimation result.

[0162] Optionally, the third processing module, when used for obtaining the third frequency offset estimation result of the target DVB-S2 burst signal, is configured to:

[0163] The reference waveform of the total pilot block information is used to realize data stripping of the frame header by performing coherent accumulation on the total pilot block information.

[0164] Fast Fourier transform is performed on a result of the data stripping, and the third frequency offset estimation result is obtained based on a result of the fast Fourier transform.

[0165] Optionally, the operation output module, when used for obtaining the large Doppler frequency offset estimation result of the target DVB-S2 burst signal, is configured to superimpose the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, and combine a captured Doppler frequency coarse estimation result F d to calculate and obtain the large Doppler frequency offset estimation result.

[0166] It can be understood that the related program modules in the device of each embodiment of the present application can be realized by a hardware processor. The DVB-S2 burst signal large Doppler frequency offset estimation device of the present application utilizes the above-mentioned program modules to realize the DVB-S2 burst signal large Doppler frequency offset estimation process of each method embodiment. When the device of the present application is used to realize the DVB-S2 burst signal large Doppler frequency offset estimation in each method embodiment, the device of the present application has the same beneficial effects as the corresponding method embodiments, and can refer to the above-mentioned method embodiments, which will not be described here.

[0167] As another aspect of the present application, the present application further provides an electronic device according to the above-mentioned embodiments, which comprises a memory, a processor and a program or instructions stored in the memory and executable on the processor. When the processor executes the program or instructions, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method according to the above-mentioned embodiments are realized.

[0168] Further, the electronic device of the present application can further comprise a communication interface and a bus. For reference Figure 6 The structure diagram of the electronic device provided by the present application comprises at least one memory 601, at least one processor 602, a communication interface 603 and a bus 604.

[0169] The memory 601, the processor 602 and the communication interface 603 communicate with each other through the bus 604. The communication interface 603 is used for information transmission between the electronic device and the DVB-S2 burst signal generation or storage device. The memory 601 stores a program or instructions executable on the processor 602. When the processor 602 executes the program or instructions, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method according to the above-mentioned embodiments are realized.

[0170] It can be understood that the electronic device at least comprises the memory 601, the processor 602, the communication interface 603 and the bus 604. The memory 601, the processor 602 and the communication interface 603 are connected to each other through the bus 604 and can communicate with each other. For example, the processor 602 reads the program instructions of the DVB-S2 burst signal large Doppler frequency offset estimation method from the memory 601. In addition, the communication interface 603 can also realize the communication connection between the electronic device and the DVB-S2 burst signal generation or storage device, and can complete the information transmission between them. For example, the communication interface 603 is used to read the target DVB-S2 burst signal.

[0171] When the electronic device is running, the processor 602 invokes the program instructions in the memory 601 to execute the methods provided by the above-mentioned method embodiments, for example, including: based on the start field information of the frame header in the target DVB-S2 burst signal, calculating the first frequency offset estimation result of the target DVB-S2 burst signal through the L&R frequency offset estimation algorithm based on the prior value compensation; decoding the physical layer signaling field information of the last L1 symbols of the frame header in the target DVB-S2 burst signal through Reed-Muller code decoding; based on the start field information and the L1 physical layer signaling field information, obtaining the second frequency offset estimation result of the target DVB-S2 burst signal through the frequency domain algorithm; obtaining all pilot block information of the target DVB-S2 burst signal, and obtaining the third frequency offset estimation result of the target DVB-S2 burst signal through coherent accumulation and fast Fourier transform on the all pilot block information; and obtaining the large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

[0172] The program instructions in the memory 601 described above can be implemented in the form of a software function unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Alternatively, all or part of the steps of the above-mentioned method embodiments can be completed by hardware related to the program instructions. The aforementioned program can be stored in a computer readable storage medium, and when the program is executed, the steps including the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0173] The application also provides a non-transitory computer readable storage medium having a program or instructions stored thereon, which, when executed by a computer, implements the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method according to the above embodiments, for example, including: based on the start field information of the frame header in the target DVB-S2 burst signal, calculating a first frequency offset estimation result of the target DVB-S2 burst signal by using the L&R frequency offset estimation algorithm based on prior value compensation; decoding the physical layer signaling field information of the last L1 symbols of the frame header in the target DVB-S2 burst signal by using Reed-Muller code decoding; based on the start field information and the L1 pieces of physical layer signaling field information, obtaining a second frequency offset estimation result of the target DVB-S2 burst signal by using a frequency domain algorithm; obtaining all pilot block information of the target DVB-S2 burst signal, and obtaining a third frequency offset estimation result of the target DVB-S2 burst signal by using coherent accumulation and fast Fourier transform on the all pilot block information; and obtaining a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

[0174] As another aspect of the application, the embodiments according to the above embodiments also provide a computer program product, which includes a computer program stored on a non-transitory computer readable storage medium, and the computer program includes program instructions, which, when executed by a computer, enable the computer to perform the DVB-S2 burst signal large Doppler frequency offset estimation method provided by the above method embodiments, for example, including: based on the start field information of the frame header in the target DVB-S2 burst signal, calculating a first frequency offset estimation result of the target DVB-S2 burst signal by using the L&R frequency offset estimation algorithm based on prior value compensation; decoding the physical layer signaling field information of the last L1 symbols of the frame header in the target DVB-S2 burst signal by using Reed-Muller code decoding; based on the start field information and the L1 pieces of physical layer signaling field information, obtaining a second frequency offset estimation result of the target DVB-S2 burst signal by using a frequency domain algorithm; obtaining all pilot block information of the target DVB-S2 burst signal, and obtaining a third frequency offset estimation result of the target DVB-S2 burst signal by using coherent accumulation and fast Fourier transform on the all pilot block information; and obtaining a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

[0175] The electronic device, the non-transitory computer readable storage medium and the computer program product provided by the application can perform the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method described in the above embodiments, and first, the starting field information of the frame header is used to perform the first step of the L&R algorithm; then, based on the physical layer signaling field information and the starting field information decoded by the Reed-Muller code, the frequency domain algorithm is used to further estimate the frequency offset by using all the frame header information; finally, all known pilot block information is used to perform accurate estimation through coherent accumulation and fast Fourier transform, and finally, accurate and simple large Doppler frequency offset estimation of the DVB-S2 burst signal is realized.

[0176] It can be understood that the above-described embodiments of the device, the electronic device and the storage medium are only illustrative, and units described as separate components can or can not be physically separated, and can be located in one place or distributed on different network units. Part or all of the modules can be selected to achieve the purpose of the embodiment according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0177] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and necessary general hardware platform, and of course, it can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium such as a U disk, a mobile hard disk, a ROM, a RAM, a magnetic disk or an optical disk, and includes a plurality of instructions for making a computer device (such as a personal computer, a server or a network device) execute the method described in the above method embodiments or some parts of the method embodiments.

[0178] In addition, those skilled in the art should understand that in the application file, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to the process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0179] In the description of the application, numerous specific details are set forth. It is to be understood that embodiments of the application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been described in detail in order to not obscure the understanding of this description. Also, it is to be understood that the various features of the application can sometimes be used to advantage without a corresponding use of other features. As such, for purposes of simplification and clarity of the

[0180] Finally, it should be noted that the above-mentioned embodiments are merely intended for describing and illustrating, not limiting, the technical solutions of the present application; even though the above-mentioned embodiments of the present application have been described in detail, those skilled in the art should understand that the technical solutions recorded in the above-mentioned embodiments can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for DVB-S2 burst signal large Doppler frequency offset estimation, characterized in that, The method comprises the following steps: Based on the starting domain information of the frame header in the target DVB-S2 burst signal, a first frequency offset estimation result of the target DVB-S2 burst signal is calculated by using an L&R frequency offset estimation algorithm based on prior value compensation, which comprises the following steps: the frame header of the target DVB-S2 burst signal is extracted, and a first carrier is obtained by performing data stripping on the frame header; The first carrier is subjected to autocorrelation operation, and the autocorrelation result is subjected to average operation to obtain an average autocorrelation noise reduction formula; Based on the average autocorrelation noise reduction formula, and according to the average autocorrelation noise reduction formula, a first formula derived by using an equal ratio series summation formula and an Euler formula is used to calculate the first frequency offset estimation result; decoding the target DVB-S2 burst signal by Reed-Muller code decoding technology, to obtain the frame header behind the target DVB-S2 burst signal L 1 symbol of physical layer signaling field information; based on the start field information and L 1. The physical layer signaling field information, by frequency domain algorithm, obtains the second frequency offset estimation result of the target DVB-S2 burst signal, which comprises: based on the start field information and L 1. The physical layer signaling field information, based on the frame header information compensated by the prior value, carries out data stripping to obtain the second carrier; The second carrier is subjected to frequency domain estimation operation to obtain a second frequency offset estimation result; All pilot block information of the target DVB-S2 burst signal is obtained, and the third frequency offset estimation result of the target DVB-S2 burst signal is obtained by performing coherent accumulation and fast Fourier transform on the all pilot block information, which comprises the following steps: the reference waveform of the all pilot block information is used to perform coherent accumulation on the all pilot block information to realize data stripping of the frame header; The result of data stripping is subjected to fast Fourier transform, and the third frequency offset estimation result is obtained based on the result of fast Fourier transform; Based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, a large Doppler frequency offset estimation result of the target DVB-S2 burst signal is obtained.

2. The method for DVB-S2 burst signal large Doppler frequency offset estimation according to claim 1, characterized in that, The frequency domain estimation operation includes a Fourier transform operation, and a maximum position of a spectral modulus peak value of a result of the Fourier transform operation is ; Correspondingly, The method further comprises the following steps: Based on the left neighboring point and the right neighboring point , the approximation of the parabolic function is derived as: ； Based on the approximation △k , the corrected position index is obtained , and the corrected second frequency offset estimation result is obtained by substituting the corrected position index into the second frequency offset estimation result.

3. The method for DVB-S2 burst signal large Doppler frequency offset estimation according to claim 1, characterized in that, The method further comprises the following steps: superimposing the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result, and combining the superimposed result with a Doppler frequency offset coarse estimation result obtained through capture F d the large Doppler frequency offset estimation result is calculated.

4. A device for DVB-S2 burst signal large Doppler frequency offset estimation according to the method of any of claims 1-3, characterized by, The method further comprises the following steps: A first processing module is configured to calculate a first frequency offset estimation result of a target DVB-S2 burst signal based on starting domain information of a frame header in the target DVB-S2 burst signal by using an L&R frequency offset estimation algorithm based on prior value compensation; a second processing module, configured to decode the frame header in the target DVB-S2 burst signal by Reed-Muller code decoding L 1 symbol of physical layer signaling field information; a third processing module, configured to acquire a second frequency offset estimation result of the target DVB-S2 burst signal based on the start domain information and L 1 the physical layer signaling domain information, through the frequency domain algorithm, obtains the second frequency offset estimation result of the target DVB-S2 burst signal; A fourth processing module is configured to obtain all pilot block information of the target DVB-S2 burst signal, and obtain a third frequency offset estimation result of the target DVB-S2 burst signal by performing coherent accumulation and fast Fourier transform on the all pilot block information; An operation output module is configured to obtain a large Doppler frequency offset estimation result of the target DVB-S2 burst signal based on the first frequency offset estimation result, the second frequency offset estimation result and the third frequency offset estimation result.

5. An electronic device comprising a memory, a processor, and a program or instructions stored on the memory and executable on the processor, characterized in that, When the processor executes the program or the instruction, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method in any one of claims 1 to 3 are implemented. 6.A non-transitory computer readable storage medium having stored thereon a program or instructions, characterized in that, When the program or the instruction is executed by the computer, the steps of the DVB-S2 burst signal large Doppler frequency offset estimation method in any one of claims 1 to 3 are implemented.

7. A computer program product, characterised in that, The computer program product comprises a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method of DVB-S2 burst signal large Doppler frequency offset estimation according to any one of claims 1 to 3.

Images