Short-burst signal carrier synchronization method, system, apparatus, device, and medium

Abstract

The application discloses a short burst signal carrier synchronization method, system, device, equipment and medium. The method comprises the following steps: performing capture processing on a first sampling stage received signal to obtain first position information; performing Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling stage received signal; performing downsampling processing on the second sampling stage received signal to obtain a first symbol stage received signal; performing frequency multiplication processing on the first symbol stage received signal to obtain a second symbol stage received signal; performing fine frequency offset compensation on the second symbol stage received signal to obtain a third symbol stage received signal; and performing phase tracking processing on the third symbol stage received signal to obtain a target received signal. The application can realize high-precision phase tracking and can be applicable to various modulation modes.

Description

Technical Field

[0001] The present application relates to the field of satellite communications, and in particular to a short burst signal carrier synchronization method, system, device, equipment and medium. Background Art

[0002] In an era of rapid development in radio communication technology, the pursuit of faster and more efficient radio communication methods has led to a significant increase in spectrum usage, resulting in an increasing shortage of spectrum resources. As spectrum resources rapidly decrease, digital narrowband communication technology is gaining increasing attention. Digital narrowband communication technology offers high spectrum rates and long-distance transmission capabilities, and the corresponding receiver technology has become a hot topic, driving the development of high-dynamic carrier receivers.

[0003] In highly dynamic environments, the Doppler effect caused by high-speed and high-acceleration carrier motion poses a challenge to satellite signal synchronization. Related technologies for synchronizing short burst signals in narrowband satellite communication systems in highly dynamic environments struggle with high-precision phase tracking and are limited to a single modulation scheme. Summary of the Invention

[0004] The present application aims to propose a short burst signal carrier synchronization method, system, device, equipment and medium, which can achieve high-precision phase tracking and is applicable to various modulation modes.

[0005] In a first aspect, an embodiment of the present application provides a short burst signal carrier synchronization method, comprising the following steps:

[0006] Capturing and processing the first sampling level received signal to obtain first position information, where the first position information is used to indicate a starting position of a frame signal in the first received signal;

[0007] Performing Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling level received signal;

[0008] downsampling the second sampling-level received signal to obtain a first symbol-level received signal;

[0009] performing frequency multiplication processing on the first symbol-level received signal to obtain a second symbol-level received signal;

[0010] performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal;

[0011] Phase tracking processing is performed on the third symbol-level received signal to obtain a target received signal.

[0012] According to some embodiments of the present application, the step of capturing and processing the first sampling level received signal to obtain the first position information includes:

[0013] performing symbol-level sliding correlation processing on the first sampling-level received signal and the local sampling-level pilot to obtain a first correlation signal;

[0014] performing coarse acquisition processing on the first correlation signal to obtain a coarse starting position;

[0015] determining a fine sliding range according to the first correlation signal and the coarse starting position;

[0016] performing sampling-level sliding correlation processing on the fine sliding range, the first sampling-level received signal and the local sampling-level pilot to obtain a second correlation signal;

[0017] performing fine acquisition processing on the second correlation signal according to the coarse starting position to obtain first position information.

[0018] According to some embodiments of the present application, the downsampling processing on the second sampling-level received signal to obtain the first symbol-level received signal comprises:

[0019] performing matched filtering processing on the second sampling-level received signal to obtain a matched filtering sampling-level received signal;

[0020] performing downsampling processing on the matched filtering sampling-level received signal to obtain the first symbol-level received signal.

[0021] According to some embodiments of the present application, the fine frequency offset compensation on the second symbol-level received signal to obtain the third symbol-level received signal comprises:

[0022] performing Doppler frequency residual compensation on the second symbol-level received signal to obtain a Doppler frequency residual compensation signal;

[0023] performing fine frequency offset estimation on the Doppler frequency residual compensation signal to obtain a first estimation result;

[0024] performing fine frequency offset compensation on the Doppler frequency residual compensation signal according to the first estimation result to obtain the third symbol-level received signal.

[0025] According to some embodiments of the present application, the phase tracking processing on the third symbol-level received signal to obtain the target received signal comprises:

[0026] performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensation signal;

[0027] extracting a data segment of a target length in the phase offset compensation signal to perform frequency multiplication processing, removing the modulation phase of the phase offset compensation signal to obtain a demodulation phase signal;

[0028] According to the demodulation phase signal, the third symbol level received signal is compensated for residual frequency offset phase offset, and a target received signal is obtained.

[0029] According to some embodiments of the present application, the third symbol level received signal is compensated for phase offset to obtain a phase offset compensated signal, including:

[0030] According to the third symbol level received signal and a local symbol level pilot, a correlation demodulation process is performed to obtain a demodulation received signal;

[0031] The demodulation received signal is subjected to phase offset estimation to obtain a second estimation result;

[0032] According to the second estimation result, the third symbol level received signal is compensated for phase offset to obtain a phase offset compensated signal.

[0033] In a second aspect, the embodiments of the present application provide a narrowband satellite communication system, including a satellite and a ground receiver, and the ground receiver communicates with the satellite through the short burst signal carrier synchronization method.

[0034] In a third aspect, the embodiments of the present application provide a short burst signal carrier synchronization device, including:

[0035] A signal acquisition module is configured to perform acquisition processing on a first sampling level received signal to obtain first position information, and the first position information is used to indicate the starting position of a frame signal in the first received signal;

[0036] A Doppler frequency offset compensation module is configured to perform Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling level received signal;

[0037] A downsampling module is configured to perform downsampling processing on the second sampling level received signal to obtain a first symbol level received signal;

[0038] A frequency multiplication module is configured to perform frequency multiplication processing on the first symbol level received signal to obtain a second symbol level received signal;

[0039] A fine frequency offset compensation module is configured to perform fine frequency offset compensation on the second symbol level received signal to obtain a third symbol level received signal;

[0040] A phase tracking module is configured to perform phase tracking processing on the third symbol level received signal to obtain a target received signal.

[0041] In a fourth aspect, the embodiments of the present application provide an electronic device, including a processor and a memory storing computer program instructions.

[0042] The processor implements the short-burst signal carrier synchronization method of the first aspect when executing the computer program instructions.

[0043] In a fifth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium stores computer program instructions, and the computer program instructions are executed by a processor to implement the short-burst signal carrier synchronization method of the first aspect.

[0044] The short-burst signal carrier synchronization method, system, device, equipment and medium of the embodiment of the present application have at least the following beneficial effects:

[0045] In the embodiment of the present application, first, the first sampling stage received signal is captured and processed to obtain first position information; then, the first received signal is compensated for Doppler frequency offset according to the first position information to obtain a second sampling stage received signal; the second sampling stage received signal is down-sampled to obtain a first symbol stage received signal; the first symbol stage received signal is multiplied to obtain a second symbol stage received signal; the second symbol stage received signal is compensated for fine frequency offset to obtain a third symbol stage received signal; finally, the third symbol stage received signal is phase tracked to obtain a target received signal. The present application can realize high-precision phase tracking and can be applied to various modulation modes.

[0046] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0047] The present application will be further described below in conjunction with the drawings and embodiments, in which:

[0048] Figure 1 A short-burst physical layer data frame structure of a satellite communication system in the related art;

[0049] Figure 2 A flowchart of an embodiment of the short-burst signal carrier synchronization method provided by the present application;

[0050] Figure 3 A BPSK constellation diagram;

[0051] Figure 4 A BPSK 2x frequency multiplication constellation diagram;

[0052] Figure 5 A QPSK constellation diagram;

[0053] Figure 6 A QPSK 4x frequency multiplication constellation diagram;

[0054] Figure 7This is the 8PSK constellation diagram;

[0055] Figure 8 This is the constellation diagram after 8PSK 8 times the frequency;

[0056] Figure 9 A schematic diagram of the overall flow of an embodiment of a short burst signal carrier synchronization method provided by the present application;

[0057] Figure 10 This is a schematic diagram of the structure of the short burst signal carrier synchronization device provided by this application;

[0058] Figure 11 This is a schematic diagram of the structure of the electronic device provided in this application. DETAILED DESCRIPTION

[0059] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present application by illustrating the examples of the present application.

[0060] In this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the elements.

[0061] In order to solve the problems in the prior art, the embodiments of the present application provide a short burst signal carrier synchronization method, system, device, equipment and medium. The following first introduces the short burst physical layer data frame structure of the narrowband satellite communication system.

[0062] refer to Figure 1As shown in the figure, the total length of a signal frame is L, that is, L symbols. The length of the pilot is L1, and the length of the data is L2. To improve acquisition accuracy and phase estimation precision, the pilot information typically uses low-order modulation schemes such as BPSK and π / 2-BPSK. To improve information transmission efficiency, the data segment commonly uses modulation schemes such as BPSK, QPSK, and 8PSK.

[0063] MPSK is a multi-level digital phase shift keying modulation method. Its constellation diagram consists of a circle with M constellation points evenly distributed in different phases. Generally, M = 2N, where N is a positive integer. Common M = 2, 4, 8, 16, and 32 are called BPSK, QPSK, and 8PSK, respectively. The equivalent baseband model of the signal is:

[0064]

[0065] Where k = 0, 1, ..., M-1. Assuming perfect time synchronization, the received signal is obtained at the ideal sampling time through the matched filter. After frequency offset estimation, it is affected by residual frequency offset and phase offset as well as Gaussian white noise. The model of the received signal is:

[0066]

[0067] In the above formula, Δf is the residual frequency deviation, f s is the symbol rate, θ is the dynamically changing carrier phase, {n k} are independent and identically distributed Gaussian random variables with mean 0 and variance σ 2 , k=1,2,...L, L is the burst frame symbol length.

[0068] Figure 2 The following is a flow chart of a short burst signal carrier synchronization method provided by an embodiment of the present application. The method is applied to an electronic device, which can be a ground receiver in a satellite communication system or other short burst signal receiving device. A short burst signal carrier synchronization method includes the following steps:

[0069] S101: Capture a first sampling level received signal to obtain first position information, where the first position information is used to indicate a starting position of a frame signal in the first received signal;

[0070] S102, performing Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling level received signal;

[0071] S103, performing downsampling processing on the second sampling level received signal to obtain a first symbol level received signal;

[0072] S104, performing frequency multiplication processing on the first symbol-level received signal to obtain a second symbol-level received signal;

[0073] S105, performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal;

[0074] S106 : Perform phase tracking processing on the third symbol-level received signal to obtain a target received signal.

[0075] In an embodiment of the present application, a first sampling-level received signal is first captured to obtain first position information; Doppler frequency offset compensation is then performed on the first received signal based on the first position information to obtain a second sampling-level received signal; the second sampling-level received signal is downsampled to obtain a first symbol-level received signal; the first symbol-level received signal is frequency-multiplied to obtain a second symbol-level received signal; fine frequency offset compensation is performed on the second symbol-level received signal to obtain a third symbol-level received signal; and finally, phase tracking is performed on the third symbol-level received signal to obtain a target received signal. The present application can achieve high-precision phase tracking and is applicable to a variety of modulation schemes.

[0076] The capture and processing of the first sampling level received signal to obtain the first position information in step S101 refers to the capture of the first sampling level received signal to determine the starting position of the frame signal. The first sampling level received signal refers to the satellite signal received by the receiver, which is a sampling level signal.

[0077] Performing Doppler offset compensation on the first received signal based on the first position information in step S102 involves first estimating the Doppler offset of the first sampling level received signal based on the starting position of the frame signal, and then performing Doppler offset compensation on the first received signal based on the Doppler offset estimation result to obtain a second sampling level received signal. The second sampling level received signal is the Doppler offset compensated signal.

[0078] In the above-mentioned step S103, the second sampling-level received signal is downsampled to obtain the first symbol-level received signal; this means that the signal is converted from the sampling level to the symbol level through downsampling. Since the input data of subsequent processing steps such as frequency multiplication and fine frequency offset compensation must be at the symbol level, the signal needs to be downsampled after step S102.

[0079] The first symbol-level received signal is frequency-multiplied in the above-mentioned step S104 because the known signal length in a frame signal of a short burst is limited. It has been verified that the accuracy of directly estimating the frequency offset using the existing known pilot information is far from meeting the tolerable range of phase tracking. Therefore, in order to improve the subsequent fine frequency offset estimation accuracy, the present application adopts a frequency-multiplication method to remove the signal modulation phase, and uses the entire frame signal length L for fine frequency offset estimation. This method greatly improves the subsequent fine frequency offset estimation accuracy and is applicable to a variety of modulation methods such as BPSK, QPSK, 8PSK, etc.

[0080] According to the expression and arrangement characteristics of the MPSK modulation signal constellation point, this application uses the frequency doubling method to remove the signal modulation phase. For example, BPSK uses 2 times the frequency, QPSK uses 4 times the frequency, and 8PSK uses 8 times the frequency. The constellation diagrams of BPSK, QPSK, and 8PSK before and after frequency doubling are as follows: Figures 3 to 8 shown.

[0081] It should be understood that frequency doubling refers to squaring. 2-times frequency multiplication means squaring the signal, and 4-times frequency multiplication means quadrupling the signal. For example, for a BPSK signal, the modulation phase of the signal in the first quadrant is 45 degrees, and the modulation phase of the signal in the second quadrant is 225 degrees. After the signal is frequency-doubled and then squared, the modulation phase of the signal in the first quadrant becomes 90 degrees, and the modulation phase of the signal in the second quadrant becomes 450 degrees, and all signals are on the positive half of the Y axis. Figure 4 As shown, all signals have the same known phase. Rotating the doubled signal 90 degrees clockwise converts the signal into a phase-free signal. The frequency multiplication process for QPSK and 8PSK signals is similar and will not be described in detail here.

[0082] In step S105 , performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal means first estimating the fine frequency offset of the second symbol-level received signal and then performing fine frequency offset compensation on the signal according to the estimation result.

[0083] Specifically, the present invention adopts an FFT-based frequency offset estimation algorithm to perform FFT operations on all signals after Doppler residual compensation corresponding to each step, and stores the maximum value m of each group of FFT operation results. max1 、m max2 、m max3 And the position p corresponding to the maximum value max1 、p max2 、p max3 , find the maximum m from the maximum value max and its corresponding position p max , at this time the maximum m max The corresponding Doppler frequency offset residual is the current Doppler frequency offset residual, using the maximum mmax The corresponding position p max Calculate and compensate for the remaining fine frequency offset after Doppler residual compensation.

[0084] In the above step S106, performing phase tracking processing on the third symbol-level received signal to obtain the target received signal refers to performing phase tracking on the signal after fine frequency offset compensation.

[0085] It should be understood that after obtaining the target received signal in step S106, subsequent steps such as deframing are required to extract valid information, and then soft demodulate and decode the valid information.

[0086] In some implementations, performing capture processing on the first sampling stage received signal to obtain the first position information may include:

[0087] Performing symbol-level sliding correlation processing on the first sampling-level received signal and the local sampling-level pilot to obtain a first correlation signal;

[0088] Performing coarse capture processing according to the first correlation signal to obtain a coarse starting position;

[0089] determining a fine sliding range according to the first correlation signal and the coarse starting position;

[0090] Performing sampling-level sliding correlation processing according to the fine sliding range, the first sampling-level received signal, and the local sampling-level pilot to obtain a second correlation signal;

[0091] Fine capture processing is performed on the second correlation signal according to the coarse starting position to obtain first position information.

[0092] In this implementation, symbol-level sliding correlation processing is first performed on the first sampling-level received signal and the local sampling-level pilot to obtain a first correlation signal. Coarse acquisition processing is then performed on the first correlation signal to obtain a coarse starting position. A fine sliding range is then determined based on the first correlation signal and the coarse starting position. Sample-level sliding correlation processing is then performed on the fine sliding range, the first sampling-level received signal, and the local sampling-level pilot to obtain a second correlation signal. Finally, fine acquisition processing is performed on the second correlation signal based on the coarse starting position to obtain first position information. This coarse-to-fine acquisition process reduces the computational complexity and resource usage of signal acquisition and Doppler frequency offset estimation.

[0093] The above-mentioned symbol-level sliding correlation processing is performed based on the first sampling-level received signal and the local sampling-level pilot. The process is to slide the first sampling-level received signal according to a step of Ns sampling points each time, and take Ns*L1 signal samples each time to correlate with the local sampling-level pilot to obtain the first correlation signal of the sampling level.

[0094] In the above-mentioned coarse capture processing based on the first correlation signal, the coarse starting position is obtained. The coarse starting position refers to the coarse starting position of the frame signal. After obtaining the first correlation signal at the sampling level in the above step, assuming the number of slides is K, the maximum is found among the K sliding correlation results. The position of the signal sliding correlation corresponding to the maximum value is the coarse starting position of the frame signal. The K sliding correlation results refer to K symbol-level correlation results. For each symbol slide (Ns sampling points), a sliding correlation result is calculated. The number of slides K is increased by one, for a total of K slides.

[0095] The above-mentioned determination of the fine sliding range based on the first correlation signal and the coarse starting position refers to determining the fine sliding range based on the number of signal sampling points Ns and the coarse starting position of the frame signal obtained by the coarse capture result, that is, taking the coarse starting position of the frame signal as a reference, sliding Ns / 2 points to the left and right respectively, for a total sliding of Ns+1 points.

[0096] The above-mentioned sampling-level sliding correlation processing is performed based on the fine sliding range, the first sampling-level received signal and the local sampling-level pilot to obtain the second correlation signal. It means that on the basis of determining the fine sliding range, the first sampling-level received signal is slid by a step of 1 sample point each time, and Ns*L1 signal sampling points are taken each time to correlate with the local sampling-level pilot to obtain the second correlation signal at the sampling level.

[0097] The above-mentioned fine capture processing of the second correlation signal according to the coarse starting position to obtain the first position information refers to performing FFT operations on Ns+1 sliding correlation results, that is, the second correlation signal, in sequence, and finding Ns+1 maximum values ​​d in the Ns+1 FFT operation results respectively. max1 d max2 … And the position idx corresponding to the maximum value max1 、idx max1 … Compare Ns+1 maximum values ​​and select the maximum d max and the position idx corresponding to the maximum max , using the maximum d max The corresponding signal sliding position is combined with the coarse capture position to determine the precise position of the frame signal, ie, the first position information.

[0098] It should be noted that after determining the precise position of the frame signal, the maximum d max The corresponding position idx max Calculate the Doppler frequency offset and compensate it. Assume that the symbol rate of the signal is f s , the FFT operation length is len, then the Doppler frequency offset estimation error range based on FFT is [-f s / len / 2,f s / len / 2].

[0099] In some implementations, downsampling the second sampling-level received signal to obtain the first symbol-level received signal may include:

[0100] performing matched filtering on the second sampling level received signal to obtain a matched filtered sampling level received signal;

[0101] Down-sampling is performed on the matched filter sampling-level received signal to obtain a first symbol-level received signal.

[0102] In this embodiment, the second sampling level received signal is first subjected to matched filtering to obtain a matched filtered sampling level received signal, and then the matched filtered sampling level received signal is downsampled to obtain a first symbol level received signal. The present application first performs matched filtering on the signal after fine capture and Doppler frequency offset compensation, and then downsamples the signal according to the known sampling multiple Ns. Placing the signal capture and Doppler frequency offset estimation module before the matched filtering can solve the problem of the effective signal being filtered out by the filter when the Doppler frequency offset is too large, and at the same time can reduce the matched filtering processing of all signals, reduce the amount of calculation, and reduce the consumption of hardware resources.

[0103] In some implementations, performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal may include:

[0104] Performing Doppler frequency offset residual compensation on the second symbol-level received signal to obtain a Doppler frequency residual compensation signal;

[0105] performing a fine frequency offset estimation on the Doppler frequency residual compensation signal to obtain a first estimation result;

[0106] Fine frequency offset compensation is performed on the Doppler frequency residual compensation signal according to the first estimation result to obtain a third symbol-level received signal.

[0107] In this embodiment, Doppler frequency offset residual compensation is first performed on the second symbol-level received signal to obtain a Doppler frequency residual compensation signal. Then, fine frequency offset estimation is performed on the Doppler frequency residual compensation signal to obtain a first estimation result. Finally, fine frequency offset compensation is performed on the Doppler frequency residual compensation signal based on the first estimation result to obtain a third symbol-level received signal. This can improve the accuracy of fine frequency offset compensation.

[0108] The above process of performing Doppler frequency offset residual compensation on the second symbol level received signal is as follows: It is known that the error range of the Doppler frequency offset estimation module is [-f s / len / 2,f s / len / 2], in order to improve the accuracy of fine frequency estimation, this application first performs Doppler frequency offset residual compensation on the entire frame signal without modulation phase before fine frequency offset estimation, with a step of -fs / len / 2, the range is [-f s / len / 2,f s / len / 2], and obtain the Doppler frequency residual compensation signal after performing Doppler frequency offset residual compensation.

[0109] In some implementations, performing phase tracking processing on the third symbol-level received signal to obtain a target received signal may include:

[0110] performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensated signal;

[0111] Extracting a data segment of a target length from the phase offset compensation signal and performing frequency multiplication processing, removing the modulation phase of the phase offset compensation signal, and obtaining a demodulated phase signal;

[0112] Residual frequency offset and phase offset compensation is performed on the third symbol-level received signal according to the demodulated phase signal to obtain a target received signal.

[0113] In this implementation, phase offset compensation is first performed on the third-symbol-level received signal to obtain a phase-offset-compensated signal. A data segment of a target length is then extracted from the phase-offset-compensated signal and subjected to frequency multiplication, removing the modulation phase of the phase-offset-compensated signal to obtain a demodulated phase signal. Finally, residual frequency offset and phase offset compensation is performed on the third-symbol-level received signal based on the demodulated phase signal to obtain the target received signal. This method can estimate and compensate for phase error and residual frequency offset, achieve high-precision phase tracking with short bursts of limited signal length, and is applicable to a variety of modulation schemes.

[0114] The performing phase offset compensation on the third symbol-level received signal to obtain the phase offset compensated signal refers to estimating the third symbol-level received signal and then performing phase offset compensation according to the phase offset estimation result to obtain the phase offset compensated signal.

[0115] The above-mentioned extraction of a data segment of a target length from the phase deviation compensation signal for frequency doubling processing and removal of the modulation phase of the phase deviation compensation signal refers to the proposal of taking a data segment of length H for frequency doubling processing and removing the modulation phase of the signal as a known signal for subsequent phase deviation estimation. Due to the problem that the phase tracking algorithm of known information cannot be applied to a frame format with only one known pilot and a short signal length, at least two known pilot sequences are required. In this embodiment, a method of extracting a data segment of a target length from the phase deviation compensation signal for frequency doubling processing is adopted to remove the modulation phase of the signal. This solves the technical difficulty of achieving high-precision phase tracking for short bursts with limited known available signal lengths, and is applicable to a variety of modulation methods such as BPSK, QPSK, 8PSK, etc.

[0116] Specifically, the data segment of the target length in the phase offset compensation signal is extracted and frequency multiplied, and the modulation phase of the phase offset compensation signal is removed. The specific process of obtaining the de-modulated phase signal is as follows:

[0117] like Figure 1 As shown, the length of the data segment is known to be L2, and the data of length H is removed from the middle of the data segment;

[0118] Perform frequency multiplication calculation on the data of length H and remove the modulation phase. For example, if the data segment modulation mode is BPSK, perform 2-frequency multiplication processing, if QPSK, perform 4-frequency multiplication processing, and if 8PSK, perform 8-frequency multiplication processing;

[0119] The average phase pha2 of the signal with a length of H after removing the modulation phase is calculated and used for the next step of residual frequency offset and phase offset estimation.

[0120] The above-mentioned residual frequency offset and phase offset compensation of the third symbol-level received signal based on the demodulated phase signal refers to estimating the residual frequency offset and phase offset of the third symbol-level received signal, and then performing residual frequency offset and phase offset compensation based on the estimation result. In this embodiment, the FFML algorithm is used to implement residual frequency offset and phase offset estimation. First, the phase pha1 is calculated using the known signal pilot information, and then the phase pha2 is calculated using the data segment of length H from which the modulation phase has been removed. Finally, the phase accumulation step is calculated using the two phases, and the step value is used to perform residual frequency offset and phase offset compensation on the entire frame of data corresponding to the third symbol-level received signal to obtain the residual frequency offset and phase offset compensated signal, that is, the target received signal.

[0121] In some implementations, performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensated signal may include:

[0122] Perform correlation demodulation processing on the third symbol-level received signal and the local symbol-level pilot to obtain a demodulated received signal;

[0123] performing phase deviation estimation on the demodulated received signal to obtain a second estimation result;

[0124] Phase offset compensation is performed on the third symbol-level received signal according to the second estimation result to obtain a phase offset compensated signal.

[0125] In this embodiment, correlation demodulation is first performed on the third-symbol-level received signal and the local symbol-level pilot to obtain a demodulated received signal. Phase offset is then estimated on the demodulated received signal to obtain a second estimation result. Finally, phase offset compensation is performed on the third-symbol-level received signal based on the second estimation result to obtain a phase offset-compensated signal. This embodiment utilizes correlation demodulation of the received signal's pilot signal and the local symbol-level pilot to remove modulation information interference, and then estimates and compensates for phase offset on the demodulated signal, reducing computational complexity and hardware resource consumption.

[0126] The above-mentioned correlation demodulation processing based on the third symbol-level received signal and the local symbol-level pilot refers to using the pilot signal of the third symbol-level received signal and the local symbol-level pilot to perform correlation demodulation to remove modulation information interference.

[0127] The following is a flow chart of a specific embodiment of the present application. Figure 9 As shown in FIG, the basic process is that the received signal undergoes signal capture, Doppler frequency offset estimation and compensation, and then is down-sampled by matched filtering and then fine frequency offset estimation and phase tracking are performed.

[0128] The signal capture and Doppler frequency offset estimation process is as follows: first, the received sampling-level signal and the local sampling-level pilot are subjected to sliding correlation with a step of Ns sampling points to identify the pilot information and estimate the rough position of the pilot; then, based on the rough position of the pilot, sliding correlation is performed with a step of 1 sampling point, sliding the length of one symbol sampling point left and right, and the correlation result is sent to the FFT module for signal fine capture and Doppler frequency offset estimation; finally, the frame signal is intercepted and Doppler frequency offset compensation is performed.

[0129] The sampling-level signal in the complete frame format after Doppler compensation is subjected to matched filtering and down-sampling processing, and then fine frequency offset estimation and compensation processing is performed.

[0130] The fine frequency offset estimation process is as follows: first, the received symbol-level signal is frequency-multiplied to remove modulation phase interference; a reasonable Doppler frequency offset residual step is designed based on the theoretical accuracy error of the Doppler frequency offset estimation algorithm; and the signal is compensated for the Doppler frequency offset residual in sequence according to the step of the Doppler frequency offset residual; then, the FFT module is used to perform FFT operation on the signal after each frequency offset residual step compensation; finally, the maximum value is found in the FFT operation result corresponding to the signal after the Doppler frequency offset residual step compensation, and the Doppler frequency offset residual is determined. At the same time, the fine frequency offset existing after the Doppler frequency offset residual compensation is calculated and compensated.

[0131] The phase tracking process is as follows: first, the signal pilot information after fine frequency offset compensation is correlated with the local symbol-level pilot to remove modulation phase interference, and the phase offset of the demodulated signal is estimated and compensated. Then, two segments of the phase offset compensated signal are taken to estimate two phase values, one segment is a known pilot sequence and the other segment is a data segment with the modulation phase removed. The phase error change step of the signal is calculated based on the two phase values. Finally, the step value is used to linearly compensate the residual frequency offset and phase offset of the entire frame signal, and the compensated signal is sent to the deframing module to extract the effective information and perform soft demodulation and decoding processing.

[0132] An embodiment of the present application further provides a narrowband satellite communication system, comprising a satellite and a ground receiver, wherein the ground receiver communicates with the satellite through the short burst signal carrier synchronization method of the above embodiment.

[0133] The narrowband satellite communication system of the embodiment of the present application is used to execute the short burst signal carrier synchronization method in the above embodiment. Its specific signal synchronization processing process is the same as the short burst signal carrier synchronization method in the above embodiment, and will not be repeated here.

[0134] Based on the short burst signal carrier synchronization method provided in the above embodiment, the present application also provides a specific implementation of the short burst signal carrier synchronization device. Figure 10 As shown, a short burst signal carrier synchronization device 200 includes:

[0135] The signal capture module 201 is configured to capture and process the first sampling level received signal to obtain first position information, where the first position information is used to indicate a starting position of a frame signal in the first received signal;

[0136] A Doppler frequency offset compensation module 202 is configured to perform Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling level received signal;

[0137] A downsampling module 203 is configured to perform downsampling processing on the second sampling level received signal to obtain a first symbol level received signal;

[0138] The frequency multiplication module 204 is configured to perform frequency multiplication processing on the first symbol-level received signal to obtain a second symbol-level received signal;

[0139] a fine frequency offset compensation module 205, configured to perform fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal;

[0140] The phase tracking module 206 is configured to perform phase tracking processing on the third symbol-level received signal to obtain a target received signal.

[0141] The short burst signal carrier synchronization device 200 of the embodiment of the present application is used to execute the short burst signal carrier synchronization method in the above embodiment. Its specific processing process is the same as the short burst signal carrier synchronization method in the above embodiment, and will not be repeated here.

[0142] Figure 11 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present application is shown.

[0143] The electronic device may include a processor 301 and a memory 302 storing computer program instructions.

[0144] Specifically, the processor 301 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0145] The memory 302 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 302 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 302 may include removable or non-removable (or fixed) media. Where appropriate, the memory 302 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 302 is a non-volatile solid-state memory.

[0146] In some embodiments, the memory 302 may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical, or other physical / tangible memory storage devices. Thus, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to an aspect of the present disclosure.

[0147] The processor 301 reads and executes computer program instructions stored in the memory 302 to implement any one of the short burst signal carrier synchronization methods in the above embodiments.

[0148] In one example, the electronic device may further include a communication interface 303 and a bus 310. Figure 3 As shown, the processor 301 , the memory 302 , and the communication interface 303 are connected via a bus 310 and communicate with each other.

[0149] The communication interface 303 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0150] Bus 310 includes hardware, software or both, and the components of online data flow metering equipment are coupled to each other. For example, but not limitation, bus can include accelerated graphics port (AGP) or other graphics bus, enhanced industry standard architecture (EISA) bus, front side bus (FSB), hypertransport (HT) interconnection, industry standard architecture (ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 310 can include one or more buses. Although the present application embodiment describes and shows specific bus, the application considers any suitable bus or interconnection.

[0151] In addition, in conjunction with the short burst signal carrier synchronization method in the above embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any of the short burst signal carrier synchronization methods in the above embodiments is implemented.

[0152] It should be understood that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, a detailed description of known methods is omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated. Those skilled in the art can make various changes, modifications, and additions, or change the order of the steps after understanding the spirit of the present application.

[0153] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, they can be, for example, electronic circuits, application specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0154] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps. In other words, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0155] Aspects of the present disclosure have been described above 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 disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box 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 or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It is also understood that each box in the block diagram and / or flowchart and the combination of the boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0156] The above description is only a specific embodiment of the present application. Those skilled in the art will clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the scope of protection of the present application.

Claims

1. A short burst signal carrier synchronization method, characterized in that: The following steps are involved: Capturing and processing the first sampling level received signal to obtain first position information, where the first position information is used to indicate a starting position of a frame signal in the first received signal; Performing Doppler frequency offset compensation on the first received signal according to the first position information, specifically comprising: performing Doppler frequency offset estimation on the first sampling level received signal according to the first position information to obtain a Doppler frequency offset estimation result, and then performing Doppler frequency offset compensation on the first received signal according to the Doppler frequency offset estimation result to obtain a second sampling level received signal; downsampling the second sampling-level received signal, converting the second sampling-level received signal from the sampling level to the symbol level to obtain a first symbol-level received signal; performing frequency multiplication processing on the first symbol-level received signal to obtain a second symbol-level received signal; performing Doppler frequency offset residual compensation on the second symbol-level received signal to obtain a Doppler frequency residual compensated signal; performing fine frequency offset estimation on the Doppler frequency residual compensated signal to obtain a first estimation result; and performing fine frequency offset compensation on the Doppler frequency residual compensated signal according to the first estimation result to obtain a third symbol-level received signal; Phase tracking processing is performed on the third symbol-level received signal to obtain a target received signal.

2. The short burst signal carrier synchronization method according to claim 1, wherein: The capturing and processing of the first sampling level received signal to obtain the first position information includes: Performing symbol-level sliding correlation processing on the first sampling-level received signal and the local sampling-level pilot to obtain a first correlation signal; performing coarse capture processing according to the first correlation signal to obtain a coarse starting position; determining a fine sliding range according to the first correlation signal and the coarse starting position; Performing sampling-level sliding correlation processing according to the fine sliding range, the first sampling-level received signal, and the local sampling-level pilot to obtain a second correlation signal; Fine capture processing is performed on the second correlation signal according to the coarse starting position to obtain first position information.

3. The short burst signal carrier synchronization method according to claim 1, wherein: The downsampling the second sampling-level received signal to obtain a first symbol-level received signal includes: performing matched filtering on the second sampling level received signal to obtain a matched filtered sampling level received signal; Down-sampling is performed on the matched filter sampling-level received signal to obtain a first symbol-level received signal.

4. The short burst signal carrier synchronization method according to claim 1, wherein: The performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal includes: Performing Doppler frequency offset residual compensation on the second symbol-level received signal to obtain a Doppler frequency residual compensated signal; performing fine frequency offset estimation on the Doppler frequency residual compensation signal to obtain a first estimation result; Fine frequency offset compensation is performed on the Doppler frequency residual compensation signal according to the first estimation result to obtain a third symbol-level received signal.

5. The short burst signal carrier synchronization method according to claim 1, characterized in that: The performing phase tracking processing on the third symbol-level received signal to obtain a target received signal includes: performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensated signal; Extracting a data segment of a target length from the phase offset compensation signal and performing frequency multiplication processing, removing the modulation phase of the phase offset compensation signal, and obtaining a demodulated phase signal; Residual frequency offset and phase offset compensation is performed on the third symbol-level received signal according to the demodulated phase signal to obtain a target received signal.

6. The short burst signal carrier synchronization method according to claim 5, characterized in that: The performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensated signal includes: Perform correlation demodulation processing on the third symbol-level received signal and the local symbol-level pilot to obtain a demodulated received signal; performing phase deviation estimation on the demodulated received signal to obtain a second estimation result; Phase offset compensation is performed on the third symbol-level received signal according to the second estimation result to obtain a phase offset compensated signal.

7. A narrowband satellite communication system, characterized in that: It comprises a satellite and a ground receiver, wherein the ground receiver communicates with the satellite through the short burst signal carrier synchronization method according to any one of claims 1 to 6.

8. A short burst signal carrier synchronization device, characterized in that: include: a signal capture module, configured to capture and process the first sampling level received signal to obtain first position information, where the first position information is used to indicate a starting position of a frame signal in the first received signal; a Doppler frequency offset compensation module, configured to perform Doppler frequency offset compensation on the first received signal according to the first position information to obtain a second sampling level received signal, specifically comprising: performing Doppler frequency offset estimation on the first sampling level received signal according to the first position information to obtain a Doppler frequency offset estimation result, and then performing Doppler frequency offset compensation on the first received signal according to the Doppler frequency offset estimation result to obtain a second sampling level received signal; a downsampling module, configured to perform downsampling processing on the second sampling-level received signal, converting the second sampling-level received signal from the sampling level to the symbol level, and obtaining a first symbol-level received signal; a frequency multiplication module, configured to perform frequency multiplication processing on the first symbol-level received signal to obtain a second symbol-level received signal; a fine frequency offset compensation module, configured to perform Doppler frequency offset residual compensation on the second symbol-level received signal to obtain a Doppler frequency residual compensation signal; perform fine frequency offset estimation on the Doppler frequency residual compensation signal to obtain a first estimation result; and perform fine frequency offset compensation on the Doppler frequency residual compensation signal according to the first estimation result to obtain a third symbol-level received signal; The phase tracking module is used to perform phase tracking processing on the third symbol-level received signal to obtain a target received signal.

9. An electronic device, characterized in that: The device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the short burst signal carrier synchronization method according to any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the short burst signal carrier synchronization method according to any one of claims 1 to 6 is implemented.

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