Short burst signal carrier synchronization method, system, device, equipment and medium

Abstract

The invention discloses a short burst signal carrier synchronization method, system, device and equipment and a medium, and the method comprises the steps: carrying out the capturing processing of a first sampling stage receiving signal, and obtaining first position information; performing Doppler frequency offset compensation on the first receiving signal according to the first position information to obtain a second sampling stage receiving signal; performing down-sampling processing on the second sampling stage receiving signal to obtain a first symbol stage receiving signal; performing frequency multiplication processing on the first symbol-level receiving signal to obtain a second symbol-level receiving signal; performing fine frequency offset compensation on the second symbol level receiving signal to obtain a third symbol level receiving signal; and performing phase tracking processing on the third symbol level receiving signal to obtain a target receiving signal. According to the invention, high-precision phase tracking can be realized, and the method can be suitable for 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 the era of rapid development of radio communication technology, people have occupied a large amount of spatial spectrum in order to seek faster and more efficient radio communication methods, resulting in increasingly tight spectrum resources. In the case of a sharp reduction in spectrum resources, digital narrowband communication technology has become increasingly valued. Digital narrowband communication technology has high spectrum rate and long-distance transmission capabilities, so the corresponding receiver technology has gradually become one of the current hot topics, promoting the development of high-dynamic carrier receivers.

[0003] In a high-dynamic environment, the Doppler effect caused by the high-speed and high-acceleration movement of the carrier poses a challenge to the synchronization of satellite signals. In related technologies, the synchronization of short burst signals of narrowband satellite communication systems in a high-dynamic environment is difficult to achieve high-precision phase tracking and can only adapt to a single modulation method. 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 can be applied to a variety of 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] Down-sampling 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] Perform 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 capture processing according to 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] Perform 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;

[0017] The second correlation signal is subjected to fine capture processing according to the coarse starting position to obtain first position information.

[0018] According to some embodiments of the present application, downsampling the second sampling level received signal to obtain a first symbol level received signal includes:

[0019] Performing matched filtering on the second sampling level received signal to obtain a matched filtered sampling level received signal;

[0020] Down-sampling is performed on the matched filter sampling level received signal to obtain a first symbol level received signal.

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

[0022] Performing Doppler frequency offset 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] 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.

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

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

[0027] Extracting a data segment of a target length from the phase offset compensation signal for frequency doubling, removing the modulation phase of the phase offset compensation signal, and obtaining a de-modulated phase signal;

[0028] 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.

[0029] According to some embodiments of the present application, performing phase offset compensation on the third symbol-level received signal to obtain a phase offset compensated signal includes:

[0030] Perform correlation demodulation processing according to the third symbol-level received signal and the local symbol-level pilot to obtain a demodulated received signal;

[0031] Performing phase deviation estimation on the demodulated received signal to obtain a second estimation result;

[0032] 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.

[0033] In a second aspect, an embodiment of the present application provides a narrowband satellite communication system, including a satellite and a ground receiver, wherein the ground receiver communicates with the satellite through the above-mentioned short burst signal carrier synchronization method.

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

[0035] A signal capture module, used to capture and process the first sampling level received signal to obtain first position information, where the first position information is used to indicate the starting position of the frame signal in the first received signal;

[0036] 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;

[0037] A down-sampling module, used for down-sampling the second sampling level received signal to obtain a first symbol level received signal;

[0038] A frequency multiplication module, used for performing 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, configured to perform fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal;

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

[0041] In a fourth aspect, an embodiment of the present application provides an electronic device, the device comprising: a processor and a memory storing computer program instructions;

[0042] When the processor executes the computer program instructions, the short burst signal carrier synchronization method as described in the first aspect is implemented.

[0043] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the short burst signal carrier synchronization method as described in the first aspect is implemented.

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

[0045] In the implementation mode of the present application, the first sampling level received signal is first captured and processed to obtain the first position information; then the first received signal is Doppler frequency offset compensated according to the first position information to obtain the second sampling level received signal; the second sampling level received signal is downsampled to obtain the first symbol level received signal; the first symbol level received signal is frequency multiplied to obtain the second symbol level received signal; the second symbol level received signal is finely compensated for frequency offset to obtain the third symbol level received signal; finally, the third symbol level received signal is phase tracked to obtain the target received signal. The present application can achieve high-precision phase tracking and can be applied to a variety of modulation methods.

[0046] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

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

[0049] Figure 2 A schematic diagram of a flow chart of an embodiment of a short burst signal carrier synchronization method provided by the present application;

[0050] Figure 3 is the BPSK constellation diagram;

[0051] Figure 4 This is the constellation diagram after BPSK double frequency;

[0052] Figure 5 is the QPSK constellation diagram;

[0053] Figure 6 This is the constellation diagram after QPSK 4 times frequency multiplication;

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

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

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

[0057] Fig.10 A schematic diagram of the structure of a short burst signal carrier synchronization device provided by the present application;

[0058] Fig.11 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 only to provide a better understanding of the present application by illustrating the examples of the present application.

[0060] In this article, 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 "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including 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. Firstly, the short burst physical layer data frame structure of the narrowband satellite communication system is introduced below.

[0062] refer to Figure 1As shown in the figure, the total length of a frame signal is L, that is, L symbols, of which the length of the pilot is L1 and the length of the data is L2. In order to improve the accuracy of capture and phase estimation, the pilot information usually uses low-order modulation methods such as BPSK and π / 2-BPSK. In order to improve the efficiency of information transmission, the modulation methods commonly used in the data segment include BPSK, QPSK, 8PSK, etc.

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

[0064]

[0065] Where k = 0, 1, ..., M-1. Assuming that the time synchronization is ideal, the received signal is obtained at the ideal sampling time through the matched filter. After the frequency offset estimation, it is affected by the 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 A schematic flow chart of a short burst signal carrier synchronization method provided by an embodiment of the present application is shown. The method is applied to an electronic device, which may be a ground receiver in a satellite communication system or other short burst signal receiving device. A short burst signal carrier synchronization method comprises the following steps:

[0069] S101, performing capture processing on 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 down-sampling 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 the implementation mode of the present application, the first sampling level received signal is first captured and processed to obtain the first position information; then the first received signal is Doppler frequency offset compensated according to the first position information to obtain the second sampling level received signal; the second sampling level received signal is downsampled to obtain the first symbol level received signal; the first symbol level received signal is frequency multiplied to obtain the second symbol level received signal; the second symbol level received signal is finely compensated for frequency offset to obtain the third symbol level received signal; finally, the third symbol level received signal is phase tracked to obtain the target received signal. The present application can achieve high-precision phase tracking and can be applied to a variety of modulation methods.

[0076] In the above step S101, the first sampling level received signal is captured and processed to obtain the first position information, which means that the first sampling level received signal is captured to determine the starting position of the frame signal. The above first sampling level received signal refers to the satellite signal received by the receiver, which is a sampling level signal.

[0077] In the above step S102, the Doppler frequency offset compensation is performed on the first received signal according to the first position information, which means that the Doppler frequency offset of the first sampling level received signal is first estimated according to the starting position of the frame signal, and then the Doppler frequency offset compensation is performed on the first received signal according to the Doppler frequency offset estimation result to obtain the second sampling level received signal. The second sampling level received signal is the Doppler frequency offset compensation signal.

[0078] In the above 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 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 can be applied 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 a 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. Double frequency multiplication means squaring the signal, and quadruple 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 doubling the frequency and squaring the signal, 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. The signal after double frequency is rotated 90 degrees clockwise to convert the signal into a signal without modulation phase. The frequency doubling processing methods of QPSK and 8PSK signals are similar and will not be described in detail here.

[0082] In the above step S105, performing fine frequency offset compensation on the second symbol-level received signal to obtain a third symbol-level received signal means firstly 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.max The corresponding position p max Calculate the remaining fine frequency offset after Doppler residual compensation and compensate it.

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

[0085] It should be understood that after obtaining the target received signal through step S106, it is necessary to perform deframing processing, extract valid information, and then perform soft demodulation and decoding on 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] Perform 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] Perform 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] The second correlation signal is finely captured according to the coarse starting position to obtain the first position information.

[0092] In this implementation, firstly, a symbol-level sliding correlation process is performed based on the first sampling-level received signal and the local sampling-level pilot to obtain a first correlation signal; then, a coarse capture process is performed based on the first correlation signal to obtain a coarse starting position; then, a fine sliding range is determined based on the first correlation signal and the coarse starting position; then, a sampling-level sliding correlation process is performed based on the fine sliding range, the first sampling-level received signal and the local sampling-level pilot to obtain a second correlation signal; finally, a fine capture process is performed on the second correlation signal based on the coarse starting position to obtain the first position information. Through the process of coarse capture followed by fine capture, the amount of calculation and resource occupation of signal capture and Doppler frequency offset estimation are reduced.

[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, and the coarse starting position refers to the coarse starting position where the frame signal is located. After the first correlation signal at the sampling level is obtained in the above steps, assuming that the number of slides is K, the maximum is found among the K sliding correlation results, and the position of the signal sliding correlation corresponding to the maximum value is the coarse starting position where the frame signal is located. Among them, the K sliding correlation results refer to K symbol-level correlation results. For each symbol (Ns sampling points) that slides, a sliding correlation result can be calculated, and the number of K is increased by one, and a total of K slides are performed.

[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 according to the fine sliding range, the first sampling level received signal and the local sampling level pilot to obtain the second correlation signal, which 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 signal 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 of 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 rough capture position to determine the precise position of the frame signal, that is, 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, performing downsampling processing on 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 implementation, the second sampling level received signal is first subjected to matched filtering to obtain a matched filtering sampling level received signal, and then the matched filtering 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 a known sampling multiple Ns. Placing the signal capture and Doppler frequency offset estimation module before matched filtering can solve the problem of effective signals 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 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 implementation, firstly, the Doppler frequency offset residual compensation is performed on the second symbol-level received signal to obtain a Doppler frequency residual compensation signal, then the Doppler frequency residual compensation signal is finely estimated to obtain a first estimation result, and finally, the Doppler frequency residual compensation signal is finely compensated according to the first estimation result to obtain a third symbol-level received signal. The accuracy of fine frequency offset compensation can be improved.

[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, the present application first performs Doppler frequency offset residual compensation on the whole 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 for frequency doubling, removing the modulation phase of the phase offset compensation signal, and obtaining a de-modulated phase signal;

[0112] The 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, firstly, the phase offset compensation is performed on the third symbol-level received signal to obtain the phase offset compensation signal; then, the data segment of the target length in the phase offset compensation signal is extracted for frequency multiplication processing, and the modulation phase of the phase offset compensation signal is removed to obtain the demodulated phase signal; finally, the residual frequency offset phase offset compensation is performed on the third symbol-level received signal according to the demodulated phase signal to obtain the target received signal. The estimation and compensation of the phase error and the residual frequency offset can be realized, and the high-precision phase tracking technology difficulty can be realized with a short burst with limited signal length, and it can be applied to a variety of modulation modes.

[0114] The above-mentioned 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 in 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, 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 in the phase deviation compensation signal for frequency doubling processing is adopted to remove the modulation phase of the signal. The technical difficulty of realizing high-precision phase tracking for short bursts with limited available signal length is solved, and it can be applied 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 for frequency doubling, and the modulation phase of the phase offset compensation signal is removed to obtain the de-modulated phase signal. The specific process is as follows:

[0117] like Figure 1 As shown, it is known that the length of the data segment is 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, QPSK performs 4-frequency multiplication processing, and 8PSK performs 8-frequency multiplication processing;

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

[0120] The above-mentioned residual frequency offset and phase offset compensation for the third symbol-level received signal according to the demodulated phase signal refers to estimating the residual frequency offset and phase offset of the third symbol-level received signal, and then compensating the residual frequency offset and phase offset according to the estimation result. In this embodiment, the FFML algorithm is used to realize the 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 with a length of H from which the modulation phase has been removed. Finally, the phase accumulation step is calculated using the two phases, and the residual frequency offset and phase offset compensation is performed on the entire frame data corresponding to the third symbol-level received signal using the step value 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 according to 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 implementation, firstly, correlation demodulation processing is performed on the third symbol-level received signal and the local symbol-level pilot to obtain a demodulated received signal; then, phase deviation estimation is performed on the demodulated received signal to obtain a second estimation result; finally, phase deviation compensation is performed on the third symbol-level received signal according to the second estimation result to obtain a phase deviation compensated signal. In this implementation, the pilot signal of the received signal is correlated with the local symbol-level pilot to remove modulation information interference, and phase deviation estimation and compensation are performed on the demodulated signal, which can reduce the amount of calculation and reduce the consumption of hardware resources.

[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. Fig. 9 As shown in FIG. 1 , the basic process is that the received signal is subjected to signal capture, Doppler frequency offset estimation and compensation, and then 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, according to the rough position of the pilot, sliding correlation is performed with a step of 1 sampling point, sliding left and right by the length of a symbol sampling point, 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 are performed.

[0130] The fine frequency offset estimation process is as follows: first, the received symbol-level signal is frequency-multiplied to remove the modulation phase interference; a reasonable Doppler frequency offset residual step is designed according to the theoretical accuracy error of the Doppler frequency offset estimation algorithm; the signal is compensated for the Doppler frequency offset residual in turn 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, use the signal pilot information after fine frequency offset compensation to correlate with the local symbol-level pilot to remove the modulation phase interference, estimate and compensate the phase offset of the demodulated signal, and then take two segments of the signal after phase offset compensation 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, and 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 also provides a narrowband satellite communication system, including 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 a short burst signal carrier synchronization device. Fig.10 As shown, a short burst signal carrier synchronization device 200 includes:

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

[0136] A Doppler frequency offset compensation module 202, 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 down-sampling module 203 is used to perform down-sampling processing on the second sampling level received signal to obtain a first symbol level received signal;

[0138] The frequency multiplication module 204 is used 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 used 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, which will not be repeated here.

[0142] Fig.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. In appropriate cases, the memory 302 may include a removable or non-removable (or fixed) medium. In appropriate cases, 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 a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Thus, in general, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) 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 the 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 parts of online data flow billing equipment are coupled to each other. For example, but not limitation, bus may include accelerated graphics port (AGP) or other graphics bus, enhanced industrial standard architecture (EISA) bus, front-end bus (FSB), hypertransport (HT) interconnection, industrial 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 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the present application considers any suitable bus or interconnection.

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

[0152] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between 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, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, 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 capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), 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, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0155] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment 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 can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0156] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity 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 protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this 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 to obtain a second sampling level received signal; Down-sampling the second sampling level received signal 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 fine frequency offset compensation on the second symbol-level received signal 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, characterized in that: The capturing and processing of the first sampling level received signal to obtain the first position information includes: Perform 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; Perform 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; The second correlation signal is subjected to fine capture processing according to the coarse starting position to obtain first position information.

3. The short burst signal carrier synchronization method according to claim 1, characterized in that: The down-sampling the second sampling level received signal to obtain the 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, characterized in that: 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 compensation 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 for frequency doubling, removing the modulation phase of the phase offset compensation signal, and obtaining a de-modulated 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 according to 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, used to capture and process the first sampling level received signal to obtain first position information, where the first position information is used to indicate the starting position of the 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; A down-sampling module, used for down-sampling the second sampling level received signal to obtain a first symbol level received signal; A frequency multiplication module, used for performing 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 fine frequency offset compensation on the second symbol-level received signal 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 comprises: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the short burst signal carrier synchronization method as described in any one of claims 1-6 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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