Satellite terminal coarse timing synchronization method, device and equipment based on blind frequency offset compensation and storage medium

Abstract

The embodiment of the invention provides a satellite terminal coarse timing synchronization method, device and equipment based on blind frequency offset compensation and a storage medium, and the method comprises the steps: estimating the range of Doppler frequency offset, and generating a blind frequency offset compensation table based on the range of Doppler frequency offset by taking a preset fixed frequency value as a step; performing blind frequency offset compensation on the synchronization signal block received by the satellite terminal according to the blind frequency offset compensation table; determining a correlation sequence according to the synchronization signal after blind frequency offset compensation and a local synchronization sequence, and obtaining a peak value and a peak value position of the correlation sequence; the maximum peak value is selected from the peak values corresponding to all the blind frequency offset compensation values in the blind frequency offset compensation table, the blind frequency offset compensation value corresponding to the maximum peak value and the peak value position serve as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal respectively, and the high-precision coarse frequency offset estimation value can be rapidly determined.

Description

Technical Field

[0001] The present application relates to the technical field of frequency offset compensation, and in particular to a satellite terminal coarse timing synchronization method, apparatus, device and storage medium based on blind frequency offset compensation. Background Art

[0002] The speed of low-orbit satellites orbiting the earth is close to the first cosmic velocity. Therefore, when the ground satellite terminal communicates with the low-orbit satellite payload, the large frequency deviation caused by the Doppler shift will affect the coarse timing synchronization between the ground satellite terminal and the low-orbit satellite payload.

[0003] When a ground satellite terminal performs coarse timing synchronization with a low-orbit satellite payload, the ground satellite terminal receives the synchronization signal block from the low-orbit satellite payload. Due to the Doppler frequency shift, there is a large Doppler frequency deviation. If the ground satellite terminal directly uses the synchronization signal block sent by the low-orbit satellite payload to perform coarse timing synchronization operations, the coarse timing synchronization will fail.

[0004] In related technologies, coarse timing synchronization is usually achieved by performing delay / frequency offset correction through ephemeris pre-compensation and then searching for autocorrelation peaks. However, this technology has insufficient accuracy and high cost. Summary of the Invention

[0005] Embodiments of the present application provide a satellite terminal coarse timing synchronization method, apparatus, device, and storage medium based on blind frequency offset compensation.

[0006] A first aspect of an embodiment of the present application provides a satellite terminal coarse timing synchronization method based on blind frequency offset compensation, comprising:

[0007] estimating a range of Doppler frequency offset, and generating a blind frequency offset compensation table based on the range of Doppler frequency offset and stepping by a preset fixed frequency value;

[0008] Performing blind frequency offset compensation on synchronization signal blocks received by the satellite terminal according to the blind frequency offset compensation table;

[0009] Determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain the peak value and peak position of the correlation sequence;

[0010] The maximum peak value is selected from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and the blind frequency offset compensation value and peak position corresponding to the maximum peak value are used as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal, respectively.

[0011] In an optional embodiment of the present application, performing blind frequency offset compensation on the synchronization signal block received by the satellite terminal according to the blind frequency offset compensation table includes:

[0012] Traverse the blind frequency offset compensation table index and read the blind frequency offset compensation values ​​in sequence;

[0013] For each blind frequency offset compensation value read, determine its corresponding normalized frequency offset value;

[0014] Constructing a frequency offset compensation table and determining an index of the frequency offset compensation table according to the normalized frequency offset value;

[0015] Querying the frequency offset compensation table according to the frequency offset compensation table index to obtain a frequency offset compensation value for performing blind frequency offset compensation on the synchronization signal block;

[0016] Blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value.

[0017] In an optional embodiment of the present application, for each read blind frequency offset compensation value, the corresponding normalized frequency offset value is determined by the following expression:

[0018]

[0019] Where Δf j is the jth blind frequency offset compensation value read, j is the index of the blind frequency offset compensation table, is the jth normalized frequency offset value, and scs is the subcarrier spacing.

[0020] In an optional embodiment of the present application, a frequency offset compensation table is constructed using the following expression:

[0021]

[0022] Where tabFre[t] is the frequency offset compensation table, t is the number of sampling points, which is determined by the sampling rate and subcarrier spacing of the synchronization signal block, t=0,1,2,...,4095,

[0023] The frequency offset compensation table index is determined based on the normalized frequency offset value using the following expression:

[0024]

[0025] in, is the jth normalized frequency deviation value, idxTab j [t] is the frequency offset compensation table index, t is the number of sampling points, and mod(·) is the modulo operation.

[0026] In an optional embodiment of the present application, blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value through the following expression:

[0027]

[0028] tabFreSig[t]=tabFre[idxTabj [t]]

[0029] in, is the synchronization signal after blind frequency offset compensation, x[n] is the signal of the synchronization signal block received by the satellite terminal, n=0,1,2,...,N-1, and N is the signal length of the synchronization signal block.

[0030] In an optional embodiment of the present application, determining a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtaining a peak value and a peak position of the correlation sequence, includes:

[0031] For each local synchronization sequence, a current correlation sequence is determined based on the synchronization signal after blind frequency offset compensation and the current local synchronization sequence;

[0032] Obtain the peak values ​​and peak positions in all correlation sequences corresponding to all local synchronization sequences.

[0033] In an optional embodiment of the present application, the current correlation sequence is determined according to the synchronization signal after blind frequency offset compensation and the current local synchronization sequence through the following expression:

[0034]

[0035] in, is the current correlation sequence, is the synchronization signal after blind frequency offset compensation, is the current local synchronization sequence, conj is a complex operation, m = 0, 1, 2, l = 0, 1, 2, ..., L-1, k = 0, 1, 2, ..., NL-1.

[0036] A second aspect of an embodiment of the present application provides a satellite terminal coarse timing synchronization device based on blind frequency offset compensation, comprising:

[0037] A generating module, configured to estimate the range of Doppler frequency offset and generate a blind frequency offset compensation table based on the range of Doppler frequency offset in steps of a preset fixed frequency value;

[0038] a compensation module, configured to perform blind frequency offset compensation on synchronization signal blocks received by the satellite terminal according to a blind frequency offset compensation table;

[0039] A determination module is used to determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain the peak value and peak position of the correlation sequence;

[0040] The selection module is used to select the maximum peak value from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and use the blind frequency offset compensation value and peak position corresponding to the maximum peak value as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal respectively.

[0041] According to a third aspect of an embodiment of the present application, a computer device is provided, comprising: a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of any of the above methods for coarse timing synchronization of a satellite terminal based on blind frequency offset compensation are implemented.

[0042] According to a fourth aspect of the embodiments of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the satellite terminal coarse timing synchronization method based on blind frequency offset compensation as described in any one of the above items are implemented.

[0043] The above technical solutions provided by the embodiments of the present application have at least some or all of the following advantages compared to the prior art:

[0044] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation described in the embodiment of the present application estimates the range of Doppler frequency offset, and generates a blind frequency offset compensation table based on the range of Doppler frequency offset in steps with a preset fixed frequency value; blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the blind frequency offset compensation table; a correlation sequence is determined based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and the peak value and peak position of the correlation sequence are obtained; the maximum peak value is selected from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and the blind frequency offset compensation value and peak position corresponding to the maximum peak value are used as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal, respectively, so that a high-precision coarse frequency offset estimation value can be quickly determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0046] Figure 1 A flowchart of a satellite terminal coarse timing synchronization method based on blind frequency offset compensation provided in one embodiment of the present application;

[0047] Figure 2 A schematic diagram of a low-orbit satellite payload periodically sending synchronization signal blocks (SSBs) according to one embodiment of the present application;

[0048] Figure 3 A schematic diagram of the signal transmission and reception process between a ground satellite terminal and a low-orbit satellite payload provided in one embodiment of the present application;

[0049] Figure 4 A schematic structural diagram of a satellite terminal coarse timing synchronization device based on blind frequency offset compensation provided in one embodiment of the present application;

[0050] Figure 5 A schematic diagram of the computer device structure provided for one embodiment of the present application. DETAILED DESCRIPTION

[0051] In the process of realizing the present application, the inventors discovered that the current coarse timing synchronization between ground satellite terminals and low-orbit satellite payloads has poor accuracy and high cost.

[0052] To address the above problems, the embodiments of the present application provide a satellite terminal coarse timing synchronization method, apparatus, device and storage medium based on blind frequency offset compensation to improve the accuracy of coarse timing synchronization between ground satellite terminals and low-orbit satellite payloads and reduce costs.

[0053] The solutions in the embodiments of the present application can be implemented using various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0054] In order to make the technical solutions and advantages of the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless they conflict.

[0055] See Figure 1 The satellite terminal coarse timing synchronization method based on blind frequency offset compensation provided in the embodiment of the present application includes the following steps S100 to S400:

[0056] S100, estimating a range of Doppler frequency offset, and generating a blind frequency offset compensation table based on the range of Doppler frequency offset in steps of a preset fixed frequency value, wherein the preset fixed frequency value may be any value between 10 and 60 kHz;

[0057] S200, performing blind frequency offset compensation on a synchronization signal block received by the satellite terminal according to a blind frequency offset compensation table, wherein the synchronization signal block received by the satellite terminal is a core signal unit in a satellite communication system that implements an initial connection between the terminal and a satellite network;

[0058] S300: Determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain the peak value and peak position of the correlation sequence. The local synchronization sequence is a key basic component in communication systems and data processing, mainly used to achieve time base alignment between the transmitter and receiver, anti-interference data verification, and persistent synchronization queue management.

[0059] S400, selecting a maximum peak value from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and using the blind frequency offset compensation value and peak position corresponding to the maximum peak value as a coarse frequency offset estimation value and a coarse timing synchronization position of the satellite terminal, respectively.

[0060] In an optional embodiment of the present application, the channel estimation of the synchronization signal may be performed using the following formula to achieve signal synchronization of the synchronization signal:

[0061]

[0062] Among them, H LS (q, k, l) is the channel estimation result of the synchronization signal, r DMRS (q, k, l) is the frequency domain signal of the synchronization signal at the receiving end, s DMRS (k, l) is the local synchronization signal sequence, q is the antenna index, k is the subcarrier index, l is the symbol index of the synchronization signal,

[0063] When the number of user equipments is 2 and the code division multiplexing group or time-frequency domain resource group corresponding to the two ports occupied by the two users occupies an even number of subcarriers, the synchronization signal sequence is grouped based on the orthogonal sequence of the inter-user synchronization signal to obtain the grouped synchronization signal, including:

[0064] Based on the orthogonal sequence of the inter-user synchronization signal, the frequency domain orthogonal code groups in the code division multiplexing group or the time-frequency domain resource group are obtained as (1, 1) and (1, -1), and the time domain orthogonal code groups are obtained as (1, 1) and (1, 1), where k = 0, 2, ... N RE ,

[0065] The synchronization signal sequences are grouped according to the frequency domain orthogonal code groups (1,1) and (1,-1) and the time domain orthogonal code groups (1,1) and (1,1) using the following expressions:

[0066]

[0067] in, and is the post-packet synchronization signal, N RE The number of resource elements actually occupied by the synchronization signal,

[0068] When each user equipment has a single antenna, the following expression is used to estimate the time error advance of the packet post-synchronization signal in the frequency domain to obtain the estimated value of the time error advance of different users:

[0069]

[0070] in, and are the estimated values ​​of the time error advance of the two users, N is N RE Half of L, L is the number of synchronization signal pilot symbols, N fft is the number of FFT points,

[0071] The joint compensation sequence is generated based on the estimated value of the time error advance by the following expression:

[0072] comp1=γ0*Δδ

[0073] comp2=γ0*(Δδ) H

[0074] comp3=γ1*(Δδ) H

[0075] comp4=γ1*Δδ

[0076]

[0077] Where comp1, comp2, comp3, and comp4 are joint compensation sequences, γ0(k) and γ1(k) are compensation sequences for the time error advance (TA) of a single user equipment, and Δδ is the compensation sequence for the difference in the time error advance (TA) between two user equipments.

[0078] The channel estimation result is compensated by the following expression:

[0079]

[0080] in, and These are the compensated frequency domain channels of two users at the corresponding antenna q, subcarrier k, and symbol l.

[0081] In an optional embodiment of the present application, in step S100, the estimating the range of the Doppler frequency shift includes:

[0082] The Doppler frequency shift is determined, and the range of the Doppler frequency deviation is estimated according to the Doppler frequency shift.

[0083] In an optional embodiment of the present application, the Doppler shift is determined by the following expression:

[0084]

[0085] Where v is the satellite speed; f c is the signal frequency; c is the speed of light; θ is the angle between the satellite's running speed and the ground terminal.

[0086] Assume v is 7.8km / s, and for low-orbit satellites, assume fc is 28G, c is 3*10^8m / s, Doppler shift f d ∈[-728kHz, +728kHz], the Doppler frequency offset range can be plus or minus 720kHz. Based on the range of plus or minus 720kHz Doppler frequency offset, a blind frequency offset compensation table freCompTab[j] with a length of 25 is generated with a preset fixed frequency value Δf=60kHz step, where the blind frequency offset compensation table index j=0, 1, 2, ..., 24, freCompTab∈{-720,-660,-600, ..., 0, ..., 600, 660, 720}. Based on the range of plus or minus 720kHz Doppler frequency offset, a blind frequency offset compensation table with a length of 49 is generated with a preset fixed frequency value of 30kHz step. Based on the range of plus or minus 720kHz Doppler frequency offset, a blind frequency offset compensation table with a length of 97 is generated with a preset fixed frequency value of 15kHz step.

[0087] In an optional embodiment of the present application, the signal transmission and reception process between the ground satellite terminal and the low-orbit satellite payload is as follows: Figure 2 As shown, the ground satellite terminal will continuously search for the low-orbit satellite payload to send the scanning beam TxSig to the ground satellite terminal at a period T. The scanning beam TxSig will carry the synchronization signal block SSB, such as Figure 3 As shown, in order to achieve coarse timing synchronization between the ground satellite terminal and the low-orbit satellite payload. Here, it is assumed that the sampling rate of the signal RxSig carrying the synchronization signal block SSB received by the ground satellite terminal is Fs′=245.76Msps. The ground satellite terminal will perform data preprocessing operations such as filtering, downsampling, and denoising on the received signal RxSig. The ground satellite terminal obtains x[n], n=0, 1, 2, ..., N-1, which carries the synchronization signal block SSB with a sampling rate of Fs=30.72Msps after downsampling by 8 times. fs is the sampling time, N = t fs Fs, uses the blind frequency offset compensation table freCompTab to perform blind frequency offset compensation on the x[n] signal with a sampling rate of 30.72Msps, and then obtains the synchronization signal block SSB after blind frequency offset compensation. Then make The correlation sequence is calculated with the primary synchronization sequence PSS (Primary Synchronization Signals) of three values ​​m = 0, 1, 2 of the local bearer group number with a length of L, and the correlation sequence is obtained. By traversing m=0, 1, 2 and j=0, 1, 2, ..., 24, the maximum correlation peak position (coarse timing synchronization position) and the coarse frequency offset estimation value are finally obtained.

[0088] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application first attempts to perform blind Doppler frequency offset compensation based on a set Doppler frequency domain table when the ground satellite terminal communicates with the low-orbit satellite payload, and then performs coarse timing synchronization based on the signal after blind compensation, thereby enabling the ground satellite terminal to perform stable coarse timing synchronization with the low-orbit satellite payload, laying the foundation for the next step of precise frequency offset estimation and precise timing synchronization.

[0089] In an optional embodiment of the present application, the signal x[n], n=0, 1, 2, ..., N-1, carrying the synchronization signal block SSB, which is obtained after data preprocessing and has a sampling rate of Fs=30.72Msps after being downsampled by a factor of 8, is processed. According to the above analysis, the signal received by the ground satellite terminal will produce a large Doppler frequency shift due to the high-speed operation of the satellite, so the frequency deviation range of the synchronization signal block SSB is approximately plus or minus 728kHz. Based on this, before the synchronization signal block SSB is correlated with the local primary synchronization sequence PSS, it is necessary to read the synchronization signal block SSB in the order of j=0, 1, 2, ..., 24 and compensate for the blind frequency deviation compensation value in the blind frequency deviation compensation table freCompTab[j] to perform blind frequency deviation compensation processing. The coarse timing synchronization calculation process based on blind frequency deviation compensation is described in detail below.

[0090] In an optional embodiment of the present application, in step S200, performing blind frequency offset compensation on the synchronization signal block received by the satellite terminal according to the blind frequency offset compensation table includes:

[0091] Traverse the blind frequency offset compensation table index and read the blind frequency offset compensation value in sequence, wherein the blind frequency offset compensation table index is j=0, 1, 2, ..., 24;

[0092] For each blind frequency offset compensation value read, determine its corresponding normalized frequency offset value;

[0093] Constructing a frequency offset compensation table and determining an index of the frequency offset compensation table according to the normalized frequency offset value;

[0094] Querying the frequency offset compensation table according to the frequency offset compensation table index to obtain a frequency offset compensation value for performing blind frequency offset compensation on the synchronization signal block;

[0095] Blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value.

[0096] In the satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application, the only parameter that needs to be acquired in real time during the entire frequency offset compensation process is the synchronization signal block, and other parameters are all preset. This can avoid the problems of spending too much time in the parameter acquisition stage and unstable parameter acquisition, and can improve the efficiency and stability of communication between the satellite terminal and the low-orbit satellite payload.

[0097] In an optional embodiment of the present application, for each read blind frequency offset compensation value, the corresponding normalized frequency offset value is determined by the following expression:

[0098]

[0099] Where Δf j is the jth blind frequency offset compensation value read, j is the index of the blind frequency offset compensation table, is the jth normalized frequency offset value, scs is the subcarrier spacing, which can be 120 kHz or 240 kHz.

[0100] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application normalizes each blind frequency offset compensation value to ensure that the frequency offset compensation value is within a certain range, thereby ensuring the stability of the frequency offset compensation of the synchronization signal block.

[0101] In an optional embodiment of the present application, a frequency offset compensation table is constructed using the following expression:

[0102]

[0103] Wherein, tabFre[t] is the frequency offset compensation table, t is the number of sampling points, which is determined according to the sampling rate and subcarrier spacing of the synchronization signal block, t=0, 1, 2, ..., 4095, scs*t=Fs′*2,

[0104] The frequency offset compensation table index is determined based on the normalized frequency offset value using the following expression:

[0105]

[0106] in, is the jth normalized frequency deviation value, idxTab j [t] is the frequency offset compensation table index, t is the number of sampling points, and mod(·) is the modulo operation.

[0107] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application constructs a frequency offset compensation table based on sampling points, and obtains the frequency offset compensation table index based on the normalized blind frequency offset compensation value, thereby ensuring the efficiency of obtaining the frequency offset compensation value, thereby improving the frequency offset compensation efficiency of the synchronization signal block.

[0108] In an optional embodiment of the present application, blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value through the following expression:

[0109]

[0110] tabFreSig[t]=tabFre[idxTab j[t]]Among them, is the synchronization signal after blind frequency offset compensation, x[n] is the signal of the synchronization signal block received by the satellite terminal, tabFreSig[mod(n,4096)] is the frequency offset compensation value, n=0, 1, 2, ..., N-1, N is the signal length of the synchronization signal block.

[0111] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application obtains the frequency offset compensation table index through the normalized blind frequency offset compensation value, and then obtains the frequency offset compensation value in the frequency offset compensation table through the frequency offset compensation table index. It can simply and quickly determine the frequency offset compensation value, thereby ensuring the efficiency of frequency offset compensation.

[0112] In an optional embodiment of the present application, determining a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtaining a peak value and a peak position of the correlation sequence, includes:

[0113] For each local synchronization sequence, the current correlation sequence is determined based on the synchronization signal after blind frequency offset compensation and the current local synchronization sequence, wherein the current local synchronization sequence In the case of m=0, 1, 2;

[0114] Obtain the peak values ​​and peak positions in all correlation sequences corresponding to all local synchronization sequences.

[0115] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application obtains multiple related sequences by comparing the synchronization signal after blind frequency offset compensation with the local synchronization sequence, and compares the peak value of each related sequence to obtain the peak value of all related sequences. The coarse frequency offset estimation value can be determined by the peak value, and the coarse timing synchronization position of the satellite terminal can be determined by the peak position, making the coarse timing synchronization process simple and fast.

[0116] In an optional embodiment of the present application, the current correlation sequence is determined according to the synchronization signal after blind frequency offset compensation and the current local synchronization sequence through the following expression:

[0117]

[0118] in, is the current correlation sequence, is the synchronization signal after blind frequency offset compensation, is the current local synchronization sequence, conj is a complex operation, m = 0, 1, 2 means that there are three groups of local primary synchronization signals PSS, corresponding to the group numbers The three values ​​of are [0,1,2], l=0,1,2,...,L-1, k=0,1,2,...,NL-1.

[0119] In an optional embodiment of the present application, j is traversed to a fixed value of 0, 1, 2, ..., 24, and m = 0, 1, 2, three sets of related sequence values ​​are calculated accordingly. Finding related sequences The maximum peak value and the maximum peak point index Traversing j will get 25 groups and right Find the maximum value and get the maximum value p corresponding to a pair of (m, j) values max and subscript index p index , according to the value of (m, j) in the blind frequency offset compensation table freqCompTab[j], j = 0, 1, 2, ..., 24, take the Δf corresponding to j j This is the rough frequency offset estimation result, and the value of m is the group number The value of the maximum value p max The corresponding subscript index p index This is the coarse timing synchronization position. Since the signal x[n], n=0, 1, 2, ..., N-1 carrying the synchronization signal block SSB is obtained after 8-fold downsampling, the accuracy of the coarse timing synchronization position in the original received signal RxSig is within 8 sampling points, and the coarse frequency offset estimate is within one-quarter of the subcarrier interval.

[0120] The satellite terminal coarse timing synchronization method based on blind frequency offset compensation of the present application traverses multiple synchronization signals after blind frequency offset compensation and multiple local synchronization sequences to obtain multiple related sequences, selects peak values ​​and peak positions from all related sequences to obtain coarse frequency offset estimation values ​​and coarse timing synchronization positions of the satellite terminal, and can ensure high precision of frequency offset compensation under the premise that the frequency offset compensation range is wide enough.

[0121] It should be understood that, although the various steps in the flowchart are shown in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps may be performed in other orders. Moreover, at least a portion of the steps in the figure may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily performed at the same time, but may be performed at different times. The execution order of these sub-steps or stages is not necessarily to be performed in sequence, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0122] See Figure 4 One embodiment of the present application provides a satellite terminal coarse timing synchronization device 400 based on blind frequency offset compensation, comprising:

[0123] A generating module 410 is configured to estimate a range of Doppler frequency offset and generate a blind frequency offset compensation table based on the range of Doppler frequency offset and in steps of a preset fixed frequency value;

[0124] The compensation module 420 is configured to perform blind frequency offset compensation on the synchronization signal blocks received by the satellite terminal according to the blind frequency offset compensation table;

[0125] A determination module 430 is configured to determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain a peak value and a peak position of the correlation sequence;

[0126] The selection module 440 is used to select the maximum peak value from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and use the blind frequency offset compensation value and peak position corresponding to the maximum peak value as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal, respectively.

[0127] For specific definitions of the apparatus 400, please refer to the above-mentioned definitions of the satellite terminal coarse timing synchronization method based on blind frequency offset compensation, and will not be repeated here. Each module in the apparatus 400 can be implemented in whole or in part via software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in the computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0128] In one embodiment, a computer device is provided, wherein the internal structure diagram of the computer device can be as follows: Figure 5 As shown. The computer device includes a processor, a memory, a network interface and a database connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data. The network interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, it implements the above-mentioned method for coarse timing synchronization of a satellite terminal based on blind frequency offset compensation. It includes: a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements any step of the above-mentioned method for coarse timing synchronization of a satellite terminal based on blind frequency offset compensation.

[0129] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, any step of the above-mentioned satellite terminal coarse timing synchronization method based on blind frequency offset compensation can be implemented.

[0130] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0131] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0132] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0134] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0135] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A satellite terminal coarse timing synchronization method based on blind frequency offset compensation, characterized in that: include: estimating a range of Doppler frequency offset, and generating a blind frequency offset compensation table based on the range of Doppler frequency offset and stepping by a preset fixed frequency value; Performing blind frequency offset compensation on synchronization signal blocks received by the satellite terminal according to the blind frequency offset compensation table; Determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain the peak value and peak position of the correlation sequence; The maximum peak value is selected from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and the blind frequency offset compensation value and peak position corresponding to the maximum peak value are used as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal, respectively.

2. The method according to claim 1, characterized in that The performing blind frequency offset compensation on the synchronization signal block received by the satellite terminal according to the blind frequency offset compensation table includes: Traverse the blind frequency offset compensation table index and read the blind frequency offset compensation values ​​in sequence; For each blind frequency offset compensation value read, determine its corresponding normalized frequency offset value; Constructing a frequency offset compensation table and determining an index of the frequency offset compensation table according to the normalized frequency offset value; Querying the frequency offset compensation table according to the frequency offset compensation table index to obtain a frequency offset compensation value for performing blind frequency offset compensation on the synchronization signal block; Blind frequency offset compensation is performed on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value.

3. The method according to claim 2, characterized in that For each blind frequency offset compensation value read, determine the corresponding normalized frequency offset value using the following expression: Where Δf j is the jth blind frequency offset compensation value read, j is the index of the blind frequency offset compensation table, is the jth normalized frequency offset value, and scs is the subcarrier spacing.

4. The method according to claim 2, characterized in that The frequency offset compensation table is constructed using the following expression: Wherein, tabFre[t] is the frequency offset compensation table, t is the number of sampling points, which is determined according to the sampling rate and subcarrier spacing of the synchronization signal block, t = 0, 1, 2, ..., 4095, The frequency offset compensation table index is determined based on the normalized frequency offset value using the following expression: in, is the jth normalized frequency deviation value, idxTab j [t] is the frequency offset compensation table index, t is the number of sampling points, and mod(·) is the modulo operation.

5. The method according to claim 2, characterized in that The following expression is used to perform blind frequency offset compensation on the synchronization signal block received by the satellite terminal according to the frequency offset compensation value: tabFreSig[t]=tabFre[idxTab j [t]] in, is the synchronization signal after blind frequency offset compensation, x[n] is the signal of the synchronization signal block received by the satellite terminal, n=0,1,2,...,N-1, and N is the signal length of the synchronization signal block.

6. The method according to claim 1, characterized in that The determining of a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtaining a peak value and a peak position of the correlation sequence, includes: For each local synchronization sequence, a current correlation sequence is determined based on the synchronization signal after blind frequency offset compensation and the current local synchronization sequence; Obtain the peak values ​​and peak positions in all correlation sequences corresponding to all local synchronization sequences.

7. The method according to claim 6, characterized in that The current correlation sequence is determined based on the synchronization signal after blind frequency offset compensation and the current local synchronization sequence using the following expression: in, is the current correlation sequence, is the synchronization signal after blind frequency offset compensation, is the current local synchronization sequence, conj is a complex operation, m = 0, 1, 2, l = 0, 1, 2, ..., L-1, k = 0, 1, 2, ..., NL-1.

8. A satellite terminal coarse timing synchronization device based on blind frequency offset compensation, characterized in that: include: A generating module, configured to estimate the range of Doppler frequency offset and generate a blind frequency offset compensation table based on the range of Doppler frequency offset and in steps of a preset fixed frequency value; a compensation module, configured to perform blind frequency offset compensation on synchronization signal blocks received by the satellite terminal according to a blind frequency offset compensation table; A determination module is used to determine a correlation sequence based on the synchronization signal after blind frequency offset compensation and the local synchronization sequence, and obtain the peak value and peak position of the correlation sequence; The selection module is used to select the maximum peak value from the peak values ​​corresponding to all blind frequency offset compensation values ​​in the blind frequency offset compensation table, and use the blind frequency offset compensation value and peak position corresponding to the maximum peak value as the coarse frequency offset estimation value and the coarse timing synchronization position of the satellite terminal respectively.

9. A computer device comprising: The method comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of the satellite terminal coarse timing synchronization method based on blind frequency offset compensation as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the satellite terminal coarse timing synchronization method based on blind frequency offset compensation according to any one of claims 1 to 7 are implemented.

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