Frequency offset estimation method and device, electronic equipment and storage medium

Abstract

The invention discloses a frequency offset estimation method and device, electronic equipment and a storage medium, and relates to the technical field of signal processing. In the invention, based on a data signal sent by a signal transmitting end and a local characteristic signal, a subsequent signal used for frequency offset estimation can be obtained, i.e., a fusion signal carrying frequency offset information is obtained; moreover, Chirp-Z transformation is carried out on the fusion signal in a limited residual frequency offset range of a data transmission channel, so that not only is spectrum information of the fusion signal meeting a fine frequency offset estimation requirement obtained, but also the calculation complexity is reduced to a certain extent as the residual frequency offset range is fine, and the accuracy of frequency offset estimation is improved. Namely, high-precision frequency offset estimation is completed under reasonable calculation complexity, so that the problem of insufficient timeliness of signal processing is solved; in addition, in the frequency offset estimation process, the frequency offset estimation precision is further improved by combining the frequency spectrum peak offset.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a frequency offset estimation method, device, electronic device and storage medium. Background Art

[0002] In the satellite digital mobile communication system, the transmitter adjusts the information to the carrier frequency, and the receiver recovers the carrier so that the phase of the constellation point of the modulation symbol does not deflect significantly, so that the symbol can be judged and accurate transmission information can be obtained.

[0003] Normally, although the receiver knows the carrier frequency of the transmitter, in order to perform carrier recovery, it is still necessary to consider the frequency differences caused by the accuracy and stability of the local clock in the frequency synthesizer, as well as the Doppler frequency shift caused by the large relative movement speed between the receiver and the transmitter.

[0004] Obviously, if the signal frequency deviation caused by the above two aspects is not corrected, there will be a large phase offset in the constellation point after demodulation, which will lead to a significant decrease in demodulation performance. Therefore, in order to correct the signal frequency deviation caused by the above two aspects, it is usually necessary to calculate the frequency deviation information and perform frequency compensation.

[0005] The traditional frequency offset estimation method is to obtain a signal with frequency offset information by conjugating the local feature code with the received signal, then perform Fast Fourier Transform (FFT) on the signal with frequency offset information and find the spectrum peak to obtain the frequency offset information in the signal.

[0006] Moreover, in the related technology, on the basis of FFT, the frequency-selective Fourier transform (Zoom FFT) and zero-padding method can also be used; wherein, the zero-padding method increases the number of measurement points in the discrete Fourier transform (DFT) to improve the approximation to the DFT. This method reduces the fence effect and obtains a local approximation of the discrete-time Fourier transform (DTFT) at a limited number of measurement points, thereby effectively improving the accuracy of frequency deviation estimation; the Zoom FFT selects the target segment signal by frequency shifting and filtering the signal, and then uses the signal resampling to perform FFT processing on the target segment signal, thereby obtaining more precise frequency deviation information.

[0007] However, when using the above-mentioned frequency offset estimation method, the frequency offset range estimated by padding with zeros based on FFT is related to the sampling rate. As a result, when the frequency offset range is large, a large number of zeros need to be padded to improve the accuracy of the frequency offset estimation. The number of FFT points is large, which leads to high computational complexity. In addition, since Zoom FFT involves frequency shifting and filtering, when the length of data to be processed is large, there is a problem of high computational complexity.

[0008] Therefore, using the above method, the computational complexity is high, resulting in insufficient timeliness of signal processing. Summary of the invention

[0009] The embodiments of the present application provide a frequency offset estimation method, device, electronic device and storage medium for completing high-precision frequency offset estimation under reasonable computational complexity, thereby improving the problem of insufficient timeliness of signal processing.

[0010] In a first aspect, an embodiment of the present application provides a frequency offset estimation method, the method comprising:

[0011] Based on the data signal sent by the signal transmitting end and the local characteristic signal set for the data signal, a fusion signal carrying frequency offset information is obtained; wherein the data signal includes the modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction;

[0012] In the residual frequency deviation range, the fused signal is subjected to Chirp-Z transformation to obtain the spectrum information of the fused signal; wherein the residual frequency deviation range represents: the residual frequency deviation of the received signal in the data transmission channel;

[0013] Based on the spectrum peak offset and residual frequency offset range associated with the spectrum information, a current frequency offset estimate is obtained; wherein the spectrum peak offset represents: a peak index offset of a first spectrum peak, the first spectrum peak being greater than multiple spectrum peaks in the spectrum information.

[0014] In a second aspect, an embodiment of the present application further provides a frequency offset estimation device, the device comprising:

[0015] A fusion module, used for obtaining a fusion signal carrying frequency deviation information based on a data signal sent by a signal transmitting end and a local characteristic signal set for the data signal; wherein the data signal includes a modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency deviation correction;

[0016] The acquisition module is used to perform Chirp-Z transform on the fused signal within the residual frequency deviation range to obtain the spectrum information of the fused signal; wherein the residual frequency deviation range represents: the residual frequency deviation of the received signal in the data transmission channel;

[0017] An estimation module is used to obtain a current frequency deviation estimate based on a spectrum peak offset and a residual frequency deviation range associated with spectrum information; wherein the spectrum peak offset represents: a peak index offset of a first spectrum peak, the first spectrum peak being greater than multiple spectrum peaks in the spectrum information.

[0018] In an optional embodiment, the residual frequency offset range is obtained in the following manner:

[0019] Determining an initial frequency offset estimation range of a current frequency offset estimation value based on motion state information of a signal transmitting end;

[0020] Based on the initial frequency offset estimation range and the frequency offset estimation value at the last historical moment, a residual frequency offset range is obtained.

[0021] In an optional embodiment, when obtaining the current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range associated with the spectrum information, the estimation module is specifically used to:

[0022] Acquire a first spectrum peak and second spectrum peaks on both sides of the first spectrum peak from the spectrum information; wherein each second spectrum peak is greater than at least one spectrum peak in the spectrum information except the first spectrum peak;

[0023] Based on the first spectrum peak and the two second spectrum peaks, obtaining a spectrum peak offset in the spectrum information;

[0024] A current frequency offset estimate is obtained based on the spectrum peak offset and the residual frequency offset range.

[0025] In an optional embodiment, when obtaining the spectrum peak offset in the spectrum information based on the first spectrum peak and the two second spectrum peaks, the estimation module is specifically used to:

[0026] A parabola difference method is used to obtain a peak index of a predicted frequency deviation peak based on a first spectrum peak and two second spectrum peaks; wherein the parabola difference method is used to fit a maximum point of a quadratic curve;

[0027] The peak index of the predicted frequency deviation peak is used as the spectrum peak offset in the spectrum information.

[0028] In an optional embodiment, when obtaining the current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range, the estimation module is specifically used to:

[0029] Obtaining an estimated value index of a current frequency offset estimated value based on a peak index of a first spectrum peak and a spectrum peak offset;

[0030] Based on the obtained estimated value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range, a current frequency offset estimate is obtained.

[0031] In an optional embodiment, when obtaining the current frequency offset estimation value based on the obtained estimation value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range, the estimation module is specifically used to:

[0032] The frequency resolution is determined based on the number of transformation points used by the Chirp-Z transform and the residual frequency deviation range; wherein the frequency resolution represents: the frequency range corresponding to a single transformation point;

[0033] Based on the estimated value index, frequency resolution and residual frequency offset range, a current frequency offset estimate is obtained.

[0034] In a third aspect, the present application provides an electronic device comprising a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes the steps of the frequency offset estimation method described in the first aspect above.

[0035] In a fourth aspect, the present application provides a computer-readable storage medium, which includes a program code. When the program code is executed on an electronic device, the program code is used to enable the electronic device to perform the frequency offset estimation steps described in the first aspect.

[0036] In a fifth aspect, the present application provides a computer program product, which, when called by a computer, enables the computer to execute the steps of the frequency offset estimation method as described in the first aspect.

[0037] The beneficial effects of this application are as follows:

[0038] In the frequency offset estimation method provided in the embodiment of the present application, based on the data signal sent by the signal transmitting end and the local characteristic signal, a signal subsequently used for frequency offset estimation can be obtained, that is, a fused signal carrying frequency offset information is obtained; and, within the limited residual frequency offset range of the data transmission channel, a Chirp-Z transform is performed on the fused signal. In this way, not only the spectrum information of the fused signal that meets the requirements of fine frequency offset estimation is obtained, but also because the residual frequency offset range is relatively fine, the computational complexity is reduced to a certain extent, that is, high-precision frequency offset estimation is completed under reasonable computational complexity, thereby improving the problem of insufficient timeliness of signal processing; in addition, in the process of frequency offset estimation, the spectrum peak offset is combined to further improve the accuracy of frequency offset estimation.

[0039] In addition, other features and advantages of the present application will be described in the subsequent description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. In the drawings:

[0041] Figure 1 A schematic diagram of a scenario of a satellite digital mobile communication system provided in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of an optional system architecture applicable to the embodiments of the present application;

[0043] Figure 3 A schematic diagram of an implementation flow of a frequency offset estimation method provided in an embodiment of the present application;

[0044] Figure 4 A schematic diagram of an implementation flow of obtaining a current frequency offset estimation value provided in an embodiment of the present application;

[0045] Figure 5 A logical schematic diagram of obtaining a spectrum peak offset provided in an embodiment of the present application;

[0046] Figure 6 A logical schematic diagram of obtaining a current frequency offset estimation value provided in an embodiment of the present application;

[0047] Figure 7 A method based on the embodiment of the present application is provided Figure 3 Schematic diagram of the

[0048] Figure 8 A schematic diagram of the structure of a frequency offset estimation device provided in an embodiment of the present application;

[0049] Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the technical solution of the present application, rather than all of the embodiments. Based on the embodiments recorded in the application documents, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the technical solution of the present application.

[0051] It should be noted that in the description of this application, "multiple" is understood as "at least two". "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. A and B are connected, which can represent two situations: A and B are directly connected and A and B are connected through C. In addition, in the description of this application, words such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

[0052] In addition, the collection, dissemination, and use of data in the technical solution of this application comply with the requirements of relevant national laws and regulations.

[0053] Some technical terms in the embodiments of the present application are explained below to facilitate understanding by those skilled in the art.

[0054] (1) Chirp-Z Transform: It is an algorithm suitable for calculating when the inverse of the product of the sampling frequency interval (SFI) and the sampling time interval (STI) is not equal to the time-frequency distribution area of ​​the signal. It is an FFT algorithm that uses convolution to implement DFT of any size.

[0055] (2) Fence effect: refers to the phenomenon that when a signal is sampled, only the information of the sampling point can be obtained, while the data information in the sampling interval is ignored. Whether it is time domain sampling or frequency domain sampling, there is a corresponding fence effect, but when the time domain sampling satisfies the sampling theorem, the fence effect will not have any effect. The fence effect of frequency domain sampling has a great impact. The "blocked" or lost frequency components may be important or characteristic components, making signal processing meaningless. The fence effect can be reduced by increasing the sampling interval, that is, the frequency resolution. The smaller the interval and the higher the frequency resolution, the fewer frequency components will be "blocked" or lost. However, the number of sampling points will be increased, which will increase the calculation workload.

[0056] (3) Parabolic Interpolation Method: It is also called quadratic interpolation method. It is a polynomial interpolation method that successively approximates the minimum point of the original function with the minimum point of the fitted quadratic curve.

[0057] Further, based on the above-mentioned nouns and related terminology explanations, the design concept of the embodiments of the present application is briefly introduced below:

[0058] In satellite digital mobile communication systems, see Figure 1 As shown, the transmitter adjusts the information to the carrier frequency f c The receiving end recovers the carrier so that the phase of the constellation point of the modulation symbol does not deflect significantly, so that the symbol can be judged and accurate transmission information can be obtained.

[0059] In general, the receiving end knows the carrier frequency f of the transmitting end. c However, to perform carrier recovery, it is also necessary to remove the frequency differences caused by the following two aspects:

[0060] 1. A frequency synthesizer is used at the receiving end to recover the carrier. Since the frequency synthesizer relies on the local clock as the time reference, the accuracy and stability of the local clock have a direct impact on the accuracy and stability of the RF and IF.

[0061] 2. In the satellite digital mobile communication system, there is a large relative motion speed between the satellite and the ground terminal, which will cause a larger Doppler frequency shift than the ground communication system. The received signal frequency is significantly different from the transmitted signal frequency. The Doppler frequency shift is generally expressed by the following formula:

[0062]

[0063] Among them, f d represents Doppler frequency shift, v represents the relative speed between the ground terminal and the satellite, f represents the carrier frequency, λ represents the wavelength, c represents the speed of light, and θ represents the angle between the ground terminal speed and the wireless signal emitted by the satellite. It should be noted that if the angle θ is less than 90 degrees, the Doppler frequency shift value is positive, and the signal frequency received by the ground terminal is greater than the signal frequency transmitted by the satellite. If the angle θ is greater than 90 degrees, the Doppler frequency shift value is negative, and the signal frequency received by the ground terminal is less than the signal frequency transmitted by the satellite.

[0064] Obviously, in the satellite digital mobile communication system, if the signal frequency deviation caused by the above two reasons is not corrected, the constellation point after demodulation will cause a large phase frequency shift and the demodulation performance will be greatly reduced; therefore, the frequency deviation information should be calculated and frequency compensation should be performed.

[0065] The traditional frequency offset estimation method is to obtain a signal with frequency offset information by conjugating and multiplying the local feature code with the received signal. The above process can be expressed by the following formula:

[0066] s=r*conj(uw)

[0067] Among them, r represents the received signal, uw represents the local feature code, and s represents the signal obtained by multiplying the received signal by the local feature code.

[0068] Furthermore, by performing FFT on the signal and finding the spectrum peak, the frequency deviation information (i.e., the frequency deviation estimation value) of the received signal can be obtained. The specific expression is as follows:

[0069] [VI]=max(abs(fft(s,nfft)))

[0070] f g =(I-1)*f s / nfft

[0071] Where V represents the maximum value of the FFT spectrum peak, I represents the index of the spectrum peak, s represents the sequence of FFT points, nfft represents the number of FFT points, and f g Represents the estimated frequency deviation value, that is, the frequency deviation estimation value, f s Indicates the signal sampling frequency.

[0072] In the related technology, on the basis of FFT, some methods based on various spectrum transformations are proposed to improve the accuracy of frequency offset estimation, such as Zoom FFT and zero-padding method; among them, the zero-padding method increases the number of measurement points in DFT to improve the approximation to DFT. This method reduces the fence effect and obtains a local approximation of DTFT at a limited number of measurement points, effectively improving the accuracy of frequency offset estimation; Zoom FFT selects the target segment signal through frequency shifting and filtering of the signal, and then uses signal resampling to perform FFT processing on the target segment signal to obtain more detailed frequency offset information.

[0073] For example, taking the FFT+zero-filling method for frequency offset estimation as an example, assuming that the signal sampling rate is f s is 240kHz, and the number of FFT points nfft is 2048, then the frequency resolution f s / nfft is approximately 117.1875 Hz; and, assuming that a signal with Doppler frequency deviation is received Among them, the true frequency deviation value f g =396Hz, then the frequency deviation estimate obtained by FFT is Using the zero padding method, the number of FFT points is increased to 8192, and the frequency offset estimate obtained by FFT is Obviously, the accuracy of frequency offset estimation is improved.

[0074] However, when using the above-mentioned frequency offset estimation method, the frequency offset range estimated by padding with zeros on the basis of FFT is related to the sampling rate. As a result, when the frequency offset range is large, a large number of zeros need to be padded to improve the accuracy of the frequency offset estimation. The number of FFT points is large, which leads to high computational complexity. In addition, since Zoom FFT involves frequency shifting and filtering, when the length of data to be processed is large, there is a problem of high computational complexity. Furthermore, there will be serious problems with the timeliness of signal processing, that is, insufficient timeliness.

[0075] In view of this, in order to complete high-precision frequency offset estimation under reasonable computational complexity, thereby improving the problem of insufficient timeliness of signal processing, in an embodiment of the present application, a frequency offset estimation method is proposed, which specifically includes: based on the data signal sent by the signal transmitting end, and the local characteristic signal set for the data signal, obtaining a fused signal carrying frequency offset information; wherein the data signal includes a modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction; then, within the residual frequency offset range, the fused signal is subjected to a Chirp-Z transform to obtain the spectrum information of the fused signal; wherein the residual frequency offset range represents: the residual frequency offset of the received signal in the data transmission channel; finally, based on the spectrum peak offset and the residual frequency offset range associated with the spectrum information, the current frequency offset estimate is obtained; wherein the spectrum peak offset represents: the peak index offset of the first spectrum peak, and the first spectrum peak is greater than multiple spectrum peaks in the spectrum information.

[0076] See also Figure 2 As shown, it is a schematic diagram of a system architecture applicable to an embodiment of the present application, and the system architecture includes: a signal transmitting end 201 and a signal receiving end 202. The signal transmitting end 201 and the signal receiving end 202 can exchange information through a communication network, wherein the communication mode adopted by the communication network may include: a wireless communication mode and a wired communication mode.

[0077] Exemplarily, the signal transmitting end 201 can access the network through cellular mobile communication technology to communicate with the signal receiving end 202, wherein the cellular mobile communication technology, for example, includes the fifth generation mobile communication (5th Generation Mobile Networks, 5G) technology.

[0078] Optionally, the signal transmitting end 201 may access the network through a short-range wireless communication mode to communicate with the signal receiving end 202, wherein the short-range wireless communication mode, for example, includes Wireless Fidelity (Wi-Fi) technology.

[0079] The embodiment of the present application does not impose any restriction on the number of communication devices involved in the above system architecture. For example, there may be more signal transmitting terminals 201, or no signal transmitting terminal 201, or other network devices may be included, such as Figure 2 As shown, only the signal transmitting end 201 and the signal receiving end 202 are described as examples, and the above-mentioned devices and their respective functions are briefly introduced below.

[0080] The signal transmitting end 201 is mainly responsible for encoding the transmitted data into a signal of a certain format so as to be suitable for transmission in the communication channel, and is usually composed of electronic components such as a digital signal processor, a modulator and a power amplifier; illustratively, the information of the relevant data service can be modulated onto the carrier frequency, so that the information after the carrier modulation is completed can be sent to the signal receiving end 202 to complete the relevant data service.

[0081] It should be noted that, in the embodiment of the present application, the signal transmitting end 201 may be a satellite.

[0082] The signal receiving end 202 is mainly used to receive data transmitted from the signal transmitting end 201, restore the received signal to the original data format, and decode and process it. It is usually composed of electronic components such as a receiving amplifier, a demodulator, and a digital signal processor. Exemplarily, the carrier can be restored so that the phase of the constellation point of the modulation symbol does not deflect significantly, so that the symbol can be judged and the correct transmission information can be obtained.

[0083] It is worth mentioning that in an embodiment of the present application, the signal receiving end 202 is used to obtain a fused signal carrying frequency deviation information based on the data signal sent by the signal transmitting end 201 and the local characteristic signal set for the data signal, and then perform a Chirp-Z transform on the fused signal within the residual frequency deviation range to obtain the spectrum information of the fused signal, thereby obtaining the current frequency deviation estimate based on the spectrum peak offset and the residual frequency deviation range associated with the spectrum information.

[0084] It should be noted that, in the embodiment of the present application, the signal receiving end 202 may be a ground terminal or a ground receiver.

[0085] The frequency offset estimation method provided by the exemplary embodiment of the present application is described below in combination with the above-mentioned system architecture and with reference to the accompanying drawings. It should be noted that the above-mentioned system architecture is only shown to facilitate understanding of the spirit and principles of the present application, and the implementation of the present application is not limited in this respect.

[0086] See also Figure 3 As shown, it is a schematic diagram of an implementation process of a frequency offset estimation method provided in an embodiment of the present application. The execution subject takes a signal receiving end as an example. The specific implementation process of the method is as follows:

[0087] S301: Obtain a fused signal carrying frequency offset information based on a data signal sent by a signal transmitting end and a local characteristic signal set for the data signal.

[0088] The data signal includes a modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction.

[0089] It should be noted that the local characteristic signal or the local characteristic signal containing a pilot sequence for frequency offset correction can be called a local characteristic code, also known as a preamble symbol or outline signal, which is a special signal mainly used to obtain accurate symbol synchronization and frequency offset correction.

[0090] Typically, in digital signal communication systems, digital numbers / data are transmitted via electromagnetic signals. In digital signals, the local characteristic signal (i.e., pilot signal) is a special signal that does not carry any data information. Similarly, the local characteristic signal is also a specific signal sequence modulated onto a carrier during the modulation process. The sequence is usually expressed as a data symbol and can be used for data identification and positioning, etc., which plays an important role in improving the reliability and robustness of the communication system. At the same time, the local characteristic signal (pilot signal) can not only reduce interference and data loss, but also process and correct the received signal, thereby obtaining more accurate data transmission results.

[0091] Specifically, the local characteristic signal is a fixed value known in advance by the signal transmitter. Therefore, the signal receiver can refer to these fixed values ​​for receiving and processing. By processing the received signal, information about signal fading and noise can be obtained, thereby compensating or correcting the received data.

[0092] Exemplarily, when executing step S301, the signal receiving end conjugate-multiplies the local characteristic signal uw and the data signal rsig to obtain a fused signal r_fd carrying / with frequency deviation information, wherein the calculation formula of the fused signal r_fd can be expressed as follows:

[0093] r_fd = rsig * conj (uw)

[0094] S302: Performing Chirp-Z transform on the fused signal within the residual frequency offset range to obtain frequency spectrum information of the fused signal.

[0095] The residual frequency deviation range represents the residual frequency deviation of the received signal in the data transmission channel.

[0096] In addition, since the data transmission channel has undergone large frequency offset compensation in the synchronization capture stage, the range of residual frequency offset is small. If the FFT transform is used to find the spectrum peak, the high sampling rate will result in a larger spectrum estimation range and insufficient estimation accuracy. The Chirp-Z transform can specify the range of frequency offset estimation (i.e., the residual frequency offset range). When the same number of spectrum transformation processing points is used, the signal spectrum resolution obtained by the Chirp-Z transform is higher, so the frequency offset estimate obtained is more accurate.

[0097] In an optional implementation, the signal receiving end may determine the initial frequency offset estimation range of the current frequency offset estimation value based on the motion state information of the signal transmitting end, and then obtain the residual frequency offset range based on the initial frequency offset estimation range and the frequency offset estimation value at the previous historical moment.

[0098] Exemplarily, the motion state of the above-mentioned signal transmitting end may be: the motion speed of the signal transmitting end, and the angle range between the signal transmitting end and the signal receiving end. If it is assumed that the signal transmitting end is a satellite and the signal receiving end is a ground receiver, then according to the motion speed of the satellite and the angle range between the satellite and the ground receiver, the approximate frequency deviation range of the ground receiver when receiving the signal (i.e., the initial frequency deviation estimation range) can be obtained, and then according to the accuracy of synchronous capture and the frequency deviation value of the data of the previous frame (i.e., the frequency deviation estimation value of the previous historical moment), the residual frequency deviation range of the Chirp-Z transform operation can be determined; it should be noted that the accuracy of synchronous capture determines the initial frequency deviation estimation range, and optionally, the residual frequency deviation range is expressed as follows:

[0099] [-Δf~Δf] or [-Δf,Δf] Unit: kHz

[0100] Wherein, Δf represents the residual frequency offset value of the received signal in the data transmission channel; it should be noted that the residual frequency offset value can be referred to as residual, which is the measurement result minus the best estimated value of the measured value (that is, the best estimated value of the true value, that is, the agreed true value), and its relationship can be expressed as follows: Among them, ν represents the residual, x represents the measurement result, Represents the best estimate of the value being measured.

[0101] S303: Obtain a current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range associated with the spectrum information.

[0102] The spectrum peak offset represents: the peak index offset of the first spectrum peak, and the first spectrum peak is greater than multiple spectrum peaks in the spectrum information; therefore, the first spectrum peak can also be considered to be the maximum spectrum peak in the spectrum information.

[0103] Exemplarily, the first spectrum peak may be represented as V, its peak index may be represented as I, and obtaining the first spectrum peak may also be represented as follows:

[0104] [VI] = CZT (r_fd)

[0105] It should be noted that the spectrum peak offset takes into account the difference between the observed value of the first spectrum peak and the true value of the first spectrum peak, thereby improving the accuracy of obtaining the current frequency offset estimate.

[0106] In an optional implementation, when executing step S303, refer to Figure 4 As shown, it is a schematic diagram of an implementation process of obtaining a current frequency offset estimation value provided by an embodiment of the present application. The execution subject still takes the signal receiving end as an example. The specific implementation process of the method is as follows:

[0107] S401: Acquire a first spectrum peak and second spectrum peaks on both sides of the first spectrum peak from spectrum information.

[0108] Each second spectrum peak is larger than at least one spectrum peak in the spectrum information except the first spectrum peak; therefore, the second spectrum peak can also be considered as the second largest spectrum peak on both sides (left and right) of the first spectrum peak.

[0109] For example, assuming that the first spectrum peak is still represented by V, the second spectrum peaks on both sides of the first spectrum peak, that is, the second largest spectrum peaks (left and right) can be represented by V -1 and V1.

[0110] S402: Obtain a spectrum peak offset in the spectrum information based on the first spectrum peak and the two second spectrum peaks.

[0111] In an alternative implementation, see Figure 5 As shown, when executing step S402, the signal receiving end adopts the parabolic difference method to obtain the peak index of the predicted frequency deviation peak based on the first spectrum peak and the two second spectrum peaks, and thus uses the peak index of the predicted frequency deviation peak as the spectrum peak offset in the spectrum information; wherein the parabolic difference method is used to fit the maximum point of the quadratic curve.

[0112] The parabola difference method can be understood as: assuming that the objective function f(x) is continuous, the three points x1, x2, and x3 satisfy x1 <x2<x3,f(x1)<f(x2)> f(x3), then we can construct a parabola:

[0113]

[0114] Therefore, i=1,2,3.(2). Therefore, as long as f(x1), f(x2), and f(x3) are not the same value, then It is a definite parabola, where the coefficients a1, a2, and a3 can be determined by formula (2). If we denote f i =f(x i )(i=1,2,3), then formula (2) can be transformed into:

[0115]

[0116] Furthermore, let the parabola The maximum point of is x4, then x4 should satisfy Right now

[0117] 2a2x4+a1=0

[0118] therefore, Using Cramer's rule, solve the above equations (3) and substitute From the formula, we can get:

[0119]

[0120] In view of this, in the embodiment of the present application, the signal receiving end determines the first spectrum peak value V and the second spectrum peak value V -1 After V1 is obtained, the peak index of the predicted frequency deviation peak can be obtained according to equation (4) in the physical line difference method. It should be noted that the above x1, x2, x3 are respectively: -1, I(0), 1, and the above f(x1), f(x2), f(x3) are respectively: V -1 , V, V1; therefore, the peak index of the predicted frequency deviation peak, that is, the spectrum peak offset can be expressed as follows:

[0121]

[0122] Wherein, δ represents the spectrum peak shift.

[0123] S403: Obtain a current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range.

[0124] In an alternative implementation, see Figure 6 As shown, when executing step S403, the signal receiving end can obtain the estimated value index of the current frequency offset estimated value based on the peak index of the first spectrum peak and the spectrum peak offset, and then obtain the current frequency offset estimated value based on the obtained estimated value index, the frequency resolution of the Chirp-Z transform and the residual frequency offset range.

[0125] Optionally, the signal receiving end may determine the frequency resolution based on the number of transformation points used by the Chirp-Z transform and the residual frequency offset range; wherein the frequency resolution represents: the frequency range corresponding to a single transformation point.

[0126] Exemplarily, it is assumed that the number of transformation points used by the Chirp-Z transform is nczt, and since the residual frequency offset range is [-Δf ~ Δf], the frequency resolution can be expressed as: 2Δf / nczt.

[0127] Furthermore, the current frequency offset estimate can be obtained based on the estimate index, the frequency resolution and the residual frequency offset range; optionally, the calculation formula of the current frequency offset estimate can be expressed as:

[0128] Fd=-Δf+[(I+δ)-1]*2Δf / nczt

[0129] Wherein, Fd represents the current frequency offset estimation value, -Δf represents the lower limit value of the residual frequency offset range, and (I+δ) represents the estimation value index.

[0130] In an optional implementation, based on the frequency offset estimation method of S301 to S303, refer to Figure 7 As shown, it is a logical schematic diagram of a frequency offset estimation method provided in an embodiment of the present application, wherein a signal receiving end obtains a fused signal carrying frequency offset information based on a data signal sent by a signal transmitting end and a local characteristic signal set for the data signal; then, within the residual frequency offset range, a Chirp-Z transform is performed on the fused signal to obtain spectrum information of the fused signal; finally, based on the spectrum peak offset associated with the spectrum information and the residual frequency offset range, a current frequency offset estimate is obtained; in this way, by performing correlation processing on the data signal and the local characteristic signal from the signal transmitting end, and then performing a Chirp-Z transform on the correlation processed signal, rather than using the traditional FFT method, spectrum information is obtained through a finite residual frequency offset (i.e., the residual frequency offset range), thereby performing spectrum peak search and spectrum peak interpolation on the spectrum information, which meets the needs of fine frequency offset estimation and can obtain an accurate current spectrum estimate.

[0131] In the frequency offset estimation method provided in the embodiment of the present application, based on the data signal sent by the signal transmitting end and the local characteristic signal, a signal subsequently used for frequency offset estimation can be obtained, that is, a fused signal carrying frequency offset information is obtained; and, within the limited residual frequency offset range of the data transmission channel, a Chirp-Z transform is performed on the fused signal. In this way, not only the spectrum information of the fused signal that meets the requirements of fine frequency offset estimation is obtained, but also because the residual frequency offset range is relatively fine, the computational complexity is reduced to a certain extent, that is, high-precision frequency offset estimation is completed under reasonable computational complexity, thereby improving the problem of insufficient timeliness of signal processing, that is, effectively improving the transmission performance of the data channel; in addition, in the process of frequency offset estimation, the spectrum peak offset is combined to further improve the frequency offset estimation accuracy.

[0132] Further, based on the same technical concept, the embodiment of the present application provides a frequency offset estimation device, which is used to implement the above method flow of the embodiment of the present application. Figure 8 As shown, the frequency offset estimation device includes: a fusion module 801, an acquisition module 802 and an estimation module 803, wherein:

[0133] A fusion module 801 is used to obtain a fusion signal carrying frequency offset information based on a data signal sent by a signal transmitting end and a local characteristic signal set for the data signal; wherein the data signal includes a modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction;

[0134] The acquisition module 802 is used to perform Chirp-Z transform on the fused signal within the residual frequency deviation range to obtain the spectrum information of the fused signal; wherein the residual frequency deviation range represents: the residual frequency deviation of the received signal in the data transmission channel;

[0135] The estimation module 803 is used to obtain the current frequency offset estimation value based on the spectrum peak offset and residual frequency offset range associated with the spectrum information; wherein the spectrum peak offset represents: the peak index offset of the first spectrum peak, and the first spectrum peak is greater than multiple spectrum peaks in the spectrum information.

[0136] In an optional embodiment, the residual frequency offset range is obtained in the following manner:

[0137] Determining an initial frequency offset estimation range of a current frequency offset estimation value based on motion state information of a signal transmitting end;

[0138] Based on the initial frequency offset estimation range and the frequency offset estimation value at the last historical moment, a residual frequency offset range is obtained.

[0139] In an optional embodiment, when obtaining the current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range associated with the spectrum information, the estimation module 803 is specifically used to:

[0140] Acquire a first spectrum peak and second spectrum peaks on both sides of the first spectrum peak from the spectrum information; wherein each second spectrum peak is greater than at least one spectrum peak in the spectrum information except the first spectrum peak;

[0141] Based on the first spectrum peak and the two second spectrum peaks, obtaining a spectrum peak offset in the spectrum information;

[0142] A current frequency offset estimate is obtained based on the spectrum peak offset and the residual frequency offset range.

[0143] In an optional embodiment, when obtaining the spectrum peak offset in the spectrum information based on the first spectrum peak and the two second spectrum peaks, the estimation module 803 is specifically used to:

[0144] A parabola difference method is used to obtain a peak index of a predicted frequency deviation peak based on a first spectrum peak and two second spectrum peaks; wherein the parabola difference method is used to fit a maximum point of a quadratic curve;

[0145] The peak index of the predicted frequency deviation peak is used as the spectrum peak offset in the spectrum information.

[0146] In an optional embodiment, when obtaining the current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range, the estimation module 803 is specifically used to:

[0147] Obtaining an estimated value index of a current frequency offset estimated value based on a peak index of a first spectrum peak and a spectrum peak offset;

[0148] Based on the obtained estimated value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range, a current frequency offset estimate is obtained.

[0149] In an optional embodiment, when obtaining the current frequency offset estimation value based on the obtained estimation value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range, the estimation module 803 is specifically used to:

[0150] The frequency resolution is determined based on the number of transformation points used by the Chirp-Z transform and the residual frequency deviation range; wherein the frequency resolution represents: the frequency range corresponding to a single transformation point;

[0151] Based on the estimated value index, frequency resolution and residual frequency offset range, a current frequency offset estimate is obtained.

[0152] Based on the same technical concept, the embodiment of the present application also provides an electronic device, which can implement the frequency offset estimation method provided in the above embodiment of the present application. In one embodiment, the electronic device can be a server, or a terminal device or other electronic device. Fig. 9 As shown, the electronic device may include:

[0153] At least one processor 901, and a memory 902 connected to the at least one processor 901. The specific connection medium between the processor 901 and the memory 902 is not limited in the embodiment of the present application. Fig. 9 In the example, the processor 901 and the memory 902 are connected via a bus 900. Fig. 9 The bus 900 is represented by a bold line, and the connection between other components is only for schematic illustration and is not intended to be limiting. The bus 900 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig. 9 Only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. Alternatively, the processor 901 can also be called a controller, and there is no limitation on the name.

[0154] In the embodiment of the present application, the memory 902 stores instructions that can be executed by at least one processor 901. The at least one processor 901 can execute a frequency offset estimation method discussed above by executing the instructions stored in the memory 902. The processor 901 can implement Figure 8 The functions of each module in the device shown.

[0155] Among them, processor 901 is the control center of the device, and can use various interfaces and lines to connect various parts of the entire control device. By running or executing instructions stored in memory 902 and calling data stored in memory 902, various functions of the device and processing data, the device can be monitored as a whole.

[0156] In one possible design, the processor 901 may include one or more processing units, and the processor 901 may integrate an application processor and a modem processor, wherein the application processor mainly processes an operating system, a user interface, and application programs, and the modem processor mainly processes wireless communications. It is understandable that the modem processor may not be integrated into the processor 901. In some embodiments, the processor 901 and the memory 902 may be implemented on the same chip, and in some embodiments, they may also be implemented separately on separate chips.

[0157] Processor 901 can be a general-purpose processor, such as a CPU, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. A general-purpose processor can be a microprocessor or any conventional processor, etc. The steps of a frequency offset estimation method disclosed in the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor.

[0158] The memory 902 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules. The memory 902 may include at least one type of storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory, a random access memory (Random Access Memory, RAM), a static random access memory (Static Random Access Memory, SRAM), a programmable read-only memory (Programmable Read Only Memory, PROM), a read-only memory (Read Only Memory, ROM), an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), a magnetic memory, a disk, an optical disk, etc. The memory 902 is any other medium that can be used to carry or store a desired program code in the form of an instruction or data structure and can be accessed by a computer, but is not limited thereto. The memory 902 in the embodiment of the present application can also be a circuit or any other device that can realize a storage function, for storing program instructions and / or data.

[0159] By designing and programming the processor 901, the code corresponding to the frequency offset estimation method described in the above embodiment can be fixed into the chip, so that the chip can execute the code when running. Figure 3 The steps of a frequency offset estimation method in the embodiment shown are as follows: How to design and program the processor 901 is a technique known to those skilled in the art and will not be described in detail here.

[0160] Based on the same inventive concept, an embodiment of the present application further provides a storage medium, which stores computer instructions. When the computer instructions are executed on a computer, the computer executes a frequency offset estimation method discussed above.

[0161] In some possible implementations, the present application also provides various aspects of a frequency offset estimation method that can also be implemented in the form of a program product, which includes program code. When the program product is run on an apparatus, the program code is used to enable the control device to execute the steps of a frequency offset estimation method according to various exemplary implementations of the present application described above in this specification.

[0162] It should be noted that, although several units or subunits of the device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided into multiple units to be embodied.

[0163] In addition, although the operations of the method of the present application are described in a specific order in the drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0164] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0165] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a server, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0166] Program code for performing the operations of the present application may be written using any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0167] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0168] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A frequency offset estimation method, characterized in that: include: Based on the data signal sent by the signal transmitting end and the local characteristic signal set for the data signal, a fusion signal carrying frequency offset information is obtained; wherein the data signal includes the modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction; Performing Chirp-Z transformation on the fused signal within the residual frequency deviation range to obtain spectrum information of the fused signal; wherein the residual frequency deviation range represents: the residual frequency deviation of the received signal in the data transmission channel; Based on the spectrum peak offset associated with the spectrum information and the residual frequency offset range, a current frequency offset estimate is obtained; wherein the spectrum peak offset represents: a peak index offset of a first spectrum peak, the first spectrum peak being greater than multiple spectrum peaks in the spectrum information.

2. The method according to claim 1, characterized in that The residual frequency deviation range is obtained in the following manner: Determining an initial frequency offset estimation range of the current frequency offset estimation value based on the motion state information of the signal transmitting end; The residual frequency offset range is obtained based on the initial frequency offset estimation range and the frequency offset estimation value at the last historical moment.

3. The method according to claim 1 or 2, characterized in that The obtaining a current frequency offset estimation value based on the spectrum peak offset associated with the spectrum information and the residual frequency offset range includes: Acquire a first spectrum peak and second spectrum peaks on both sides of the first spectrum peak from the spectrum information; wherein each second spectrum peak is greater than at least one spectrum peak in the spectrum information except the first spectrum peak; Based on the first spectrum peak and the two second spectrum peaks, obtaining a spectrum peak offset in the spectrum information; The current frequency offset estimation value is obtained based on the spectrum peak offset and the residual frequency offset range.

4. The method according to claim 3, characterized in that The obtaining, based on the first spectrum peak value and the two second spectrum peak values, a spectrum peak offset in the spectrum information comprises: Using a parabola difference method, based on the first spectrum peak and the two second spectrum peaks, a peak index of a predicted frequency deviation peak is obtained; wherein the parabola difference method is used to fit a maximum point of a quadratic curve; The peak index of the predicted frequency deviation peak is used as the spectrum peak offset in the spectrum information.

5. The method according to claim 3, characterized in that The obtaining the current frequency offset estimation value based on the spectrum peak offset and the residual frequency offset range includes: Obtaining an estimated value index of the current frequency offset estimated value based on a peak index of the first spectrum peak and the spectrum peak offset; The current frequency offset estimate is obtained based on the obtained estimate value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range.

6. The method according to claim 5, characterized in that The obtaining the current frequency offset estimate value based on the obtained estimate value index, the frequency resolution of the Chirp-Z transform, and the residual frequency offset range includes: The frequency resolution is determined based on the number of transformation points used by the Chirp-Z transform and the residual frequency offset range; wherein the frequency resolution represents: the frequency range corresponding to a single number of transformation points; The current frequency offset estimation value is obtained based on the estimation value index, the frequency resolution and the residual frequency offset range.

7. A frequency offset estimation device, characterized in that: include: A fusion module, configured to obtain a fusion signal carrying frequency offset information based on a data signal sent by a signal transmitting end and a local characteristic signal set for the data signal; wherein the data signal includes a modulated local characteristic signal, and the local characteristic signal includes a pilot sequence for frequency offset correction; An acquisition module is used to perform Chirp-Z transform on the fused signal within a residual frequency deviation range to obtain spectrum information of the fused signal; wherein the residual frequency deviation range represents: the residual frequency deviation of the received signal in the data transmission channel; An estimation module is used to obtain a current frequency offset estimation value based on a spectrum peak offset associated with the spectrum information and the residual frequency offset range; wherein the spectrum peak offset represents: a peak index offset of a first spectrum peak, the first spectrum peak being greater than multiple spectrum peaks in the spectrum information.

8. The device according to claim 7, characterized in that When obtaining the current frequency offset estimation value based on the spectrum peak offset associated with the spectrum information and the residual frequency offset range, the estimation module is specifically used to: Acquire a first spectrum peak and second spectrum peaks on both sides of the first spectrum peak from the spectrum information; wherein each second spectrum peak is greater than at least one spectrum peak in the spectrum information except the first spectrum peak; Based on the first spectrum peak and the two second spectrum peaks, obtaining a spectrum peak offset in the spectrum information; The current frequency offset estimation value is obtained based on the spectrum peak offset and the residual frequency offset range.

9. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

10. 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 method according to any one of claims 1 to 6 are implemented.

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