Frequency domain carrier synchronization method and device based on sparse pilot frequency

Abstract

The invention discloses a frequency domain carrier synchronization method and device based on sparse pilot frequency, and relates to the technical field of carrier frequency synchronization. The method comprises the following steps: a transmitting end generates a data sequence and an original UW sequence; the transmitting end inserts the original UW sequence into the data sequence in an equally-spaced postposition manner to obtain a first data transmission frame, and sends the first data transmission frame to a receiving end; the receiving end detects the received second data transmission frame and determines the maximum peak position of the frequency domain signal; the receiving end determines a frequency offset estimation value according to the maximum peak position of the frequency domain signal; and the receiving end performs deviation correction on the second data transmission frame based on the frequency deviation estimation value to obtain the first data transmission frame. According to the method, influence factors in the actual communication transmission process are comprehensively considered, and the anti-interference performance of frequency offset estimation and the precision of frequency offset estimation are improved.

Description

Technical Field

[0001] The present application relates to the field of carrier frequency synchronization technology, and in particular to a frequency domain carrier synchronization method and device based on sparse pilot. Background Art

[0002] With the rapid development of wireless communications, the demand for data transmission from different satellite systems is growing, and the integration of wireless communications and mobile communication systems is becoming more and more common. The requirements for data transmission rate, stability and reliability in the field of wireless communications are increasing day by day. As a key link to ensure accurate signal transmission, carrier synchronization technology is becoming more and more important. At present, burst communication systems are used in key communication fields such as satellite communications and airborne command and emergency communications. When the communication system works in a high-dynamic environment, the Doppler frequency shift caused by the relative movement of the two communicating parties and the difference in the oscillator frequency of the transmitter and receiver cause the system to have a large frequency deviation, which has an adverse effect on the communication quality.

[0003] Existing burst communication systems divide carrier synchronization into feedforward and feedback modes according to the working mode. According to whether pilot assistance is required, it can be divided into data-assisted and non-data-assisted types. The feedforward mode is usually combined with data assistance to complete carrier synchronization, and is generally used for burst communication carrier synchronization. The feedback mode is based on the phase-locked loop, which directly extracts coherent carriers from the received signal and can make full use of frequency band resources. However, when there is a large relative speed between the communicating parties, the severe Doppler effect will cause a large carrier Doppler frequency shift, or even a large Doppler frequency shift change rate.

[0004] In addition, the traditional frequency deviation estimation method is achieved by performing conjugate multiplication of the front and rear pilots and summing them up. If the data segment has M pilots, after the conjugate multiplication of the front and rear pilots and summing them up, M-1 complex results are obtained, and then the complex results are transformed to calculate M-1 frequency deviation values, and then the average of the frequency deviation values ​​is calculated to obtain the final frequency deviation value. However, this traditional frequency deviation estimation method has the problem of low accuracy, especially in a low signal-to-noise ratio environment, the frequency deviation capture ability is weak, and the frequency deviation value cannot be accurately estimated, which causes the receiving end to be unable to correctly identify the synchronization information, and even causes communication interruption, showing poor anti-interference performance, and low estimation accuracy. Summary of the invention

[0005] The embodiment of the present application solves the problem of transmission signal distortion or spectrum imbalance in the prior art by providing a frequency domain carrier synchronization method and device based on sparse pilot. By using a data-assisted feedforward working mode, the original UW sequence of the transmitter and the first UW sequence of the receiver are correlated and calculated, and the conjugate sum is used to obtain complex data. The time domain signal is then converted into a frequency domain signal through a fast Fourier transform, and the position of the power spectrum peak is calculated, and then the frequency deviation value is calculated. The problem of poor anti-interference performance of frequency deviation estimation is effectively solved, and the accuracy of frequency deviation estimation is improved.

[0006] In the first aspect, an embodiment of the present application provides a frequency domain carrier synchronization method based on sparse pilot, including: a transmitting end generates a data sequence and an original UW sequence; the transmitting end inserts the original UW sequence into the data sequence in an evenly spaced post-position manner to obtain a first data transmission frame, and sends the first data transmission frame to a receiving end; the receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal; the receiving end determines a frequency offset estimation value based on the maximum peak position of the frequency domain signal; the receiving end performs deviation correction on the second data transmission frame based on the frequency offset estimation value to obtain the first data transmission frame.

[0007] In a possible implementation, after the transmitting end inserts the original UW sequence into the data sequence in an evenly spaced post-position manner to obtain a first data transmission frame, the method further includes: performing modulation and noise addition processing on the first data transmission frame; wherein the modulation and noise addition processing includes: performing double-sideband modulation on the baseband signal in the first data transmission frame to obtain a modulated signal; adding noise to the modulated signal using an optimized Gaussian channel; wherein the optimized Gaussian channel includes introducing a multipath fading channel into the Gaussian channel.

[0008] In a possible implementation, the receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal, including: the receiving end extracts the second data transmission frame to obtain a first UW sequence; performs correlation calculation on the first UW sequence and the original UW sequence to obtain an extracted sequence; and determines the maximum peak position of the frequency domain signal based on the extracted sequence.

[0009] In a possible implementation, performing correlation calculation on the first UW sequence and the original UW sequence to obtain an extracted sequence includes: performing correlation calculation on the first UW sequence and the original UW sequence according to a correlation formula to obtain an extracted sequence; the correlation formula is as follows: ; In the formula, represents a correlation value between the first received UW sequence and the original UW sequence, that is, the extracted sequence, represents the first UW sequence received, represents the original UW sequence, represents taking the conjugate of the original UW sequence, Indicates the number of the first UW sequence and the original UW sequence.

[0010] In a possible implementation, determining the maximum peak position of the frequency domain signal according to the extraction sequence includes: based on the extraction sequence, using a fast Fourier transform method to perform signal conversion to determine the position of the maximum power spectrum of the frequency domain signal; determining the maximum peak position according to the position of the maximum power spectrum of the frequency domain signal.

[0011] In a possible implementation, the method of performing signal conversion based on the extraction sequence using the fast Fourier transform method to determine the position of the maximum power spectrum of the frequency domain signal includes: performing signal conversion based on the extraction sequence using the fast Fourier transform method to determine the power spectrum of the frequency domain signal; traversing the power spectrum to determine multiple local peaks; according to a peak screening strategy, determining the maximum power spectrum and its corresponding frequency domain index from the multiple local peaks; wherein the peak screening strategy includes taking the local peak with the highest correlation with the original UW sequence as the maximum power spectrum; mapping the frequency domain index to the frequency axis, taking the position of the frequency corresponding to the maximum power spectrum as the position of the maximum power spectrum, and determining the frequency range of the frequency domain according to the position of the maximum power spectrum; the maximum peak position of the frequency domain signal is the position of the maximum power spectrum.

[0012] In a possible implementation manner, the receiving end determines the frequency offset estimation value according to the maximum peak position, including: the receiving end determines the frequency offset estimation value according to the maximum peak position and a frequency offset estimation formula; the frequency offset estimation formula is as follows: ; In the formula, represents the frequency offset estimation value, represents the maximum peak position, represents the sampling rate, Indicates the length of the data block. Represents the number of points of the Fast Fourier Transform.

[0013] In the second aspect, an embodiment of the present application provides a device for frequency domain carrier synchronization based on sparse pilot, including: a data acquisition module, used for a transmitting end to generate a data sequence and an original UW sequence; a data processing module, used for the transmitting end to insert the original UW sequence into the data sequence in an evenly spaced post-position manner to obtain a first data transmission frame, and send the first data transmission frame to a receiving end; the receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal; a frequency deviation calculation module, used for the receiving end to determine the frequency deviation estimation value according to the maximum peak position of the frequency domain signal; a carrier synchronization module, used for the receiving end to perform deviation correction on the second data transmission frame based on the frequency deviation estimation value to obtain the first data transmission frame.

[0014] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: The embodiment of the present application adopts a frequency domain carrier synchronization method and device based on sparse pilot, which effectively solves the problems of low estimation accuracy and poor noise resistance in the frequency offset estimation process. Based on the cross-distributed data structure composed of the data sequence and the original UW sequence, the first UW sequence received by the receiving end is conjugate summed with the original UW sequence. The position of the maximum peak is determined by fast Fourier transform, and the frequency offset estimation value is determined according to the maximum peak position. Taking into account the actual signal transmission environment, especially in a low signal-to-noise ratio environment, while simplifying the calculation, the robustness and anti-interference of the frequency offset estimation are enhanced, and the accuracy of the frequency offset estimation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A flowchart of a frequency domain carrier synchronization method based on sparse pilot provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a first data transmission frame provided in an embodiment of the present application; Figure 3 A result diagram of a frequency offset estimation experiment provided in an embodiment of the present application; Figure 4 A result diagram of a traditional frequency offset estimation experiment provided in an embodiment of the present application; Figure 5 A schematic structural diagram of a frequency domain carrier synchronization device based on sparse pilot provided in an embodiment of the present application.

[0017] In the accompanying drawings, the modules represented by a frequency domain carrier synchronization device 500 based on sparse pilots are described as follows: Data acquisition module 501, data processing module 502, frequency deviation calculation module 503, carrier synchronization module 504. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] The following describes some of the techniques involved in the embodiments of the present application to facilitate understanding, and they should be considered as merely exemplary. Therefore, it should be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, some descriptions of well-known functions and structures are omitted in the following description.

[0020] Figure 1 This is a flowchart of a frequency domain carrier synchronization method based on sparse pilot provided in an embodiment of the present application, including steps 101 to 105. Figure 1 This is only an execution order shown in the embodiment of the present application, and does not represent the only execution order of the frequency domain carrier synchronization method based on sparse pilot. In the case where the final result can be achieved, Figure 1 The steps shown may be performed in parallel or in reverse, as follows.

[0021] Step 101: The transmitting end generates a data sequence and an original UW sequence.

[0022] In the embodiment of the present application, since the original UW sequence has a unique pattern and good autocorrelation, the receiving end of the data transmission can more easily identify the original UW sequence, thereby more accurately achieving frame synchronization and timing recovery, and significantly improving the accuracy of carrier synchronization. Therefore, the original UW sequence is used as a pilot sequence. In addition, the original UW sequence has a shorter length and higher spectral efficiency. Combining the data sequence with the original UW sequence can support a variety of communication scenarios and transmission requirements without adding additional spectrum overhead, and achieve efficient synchronization and data transmission.

[0023] Step 102: The transmitting end inserts the original UW sequence into the data sequence in a post-positioned manner at equal intervals to obtain a first data transmission frame, and sends the first data transmission frame to the receiving end.

[0024] Among them, Figure 2As shown, at the transmitting end of data transmission, the data sequence of the original bit stream and the original UW sequence are generated, and the original UW sequence is inserted into the data sequence in an evenly spaced manner to form a cross-distributed form. The first data transmission frame consists of data segments.

[0025] Exemplarily, there is the following first data transmission frame: like The data sequence, like The original UW sequence.

[0026] Will The sequence is inserted at equal intervals. The data sequence, and so on, will The original UW sequence is inserted into the data sequence to form the first data block (such as including and , , and ).

[0027] The final co-generation data blocks, data blocks constitute the first data transmission frame (such as including ).

[0028] Compared with the traditional transmission frame of the transmitting end, the cross-distribution structure provided in the embodiment of the present application ensures the uniform distribution of the original UW sequence and provides a reference point for frequency offset estimation for the entire first data transmission frame. The communication quality is no longer affected by the low signal-to-noise ratio of a certain data sequence, the computational complexity of frequency offset estimation is reduced, and the estimation error caused by relying on a small number of pilot signal time intervals in the prior art is reduced.

[0029] At the transmitting end, the original UW sequence is inserted into the data sequence in an evenly spaced manner to obtain the first data transmission frame, and then the first data transmission frame can be modulated and noise-added. Modulation and noise-adding can simulate the signal degradation process in a real communication environment and is suitable for performance testing in complex scenarios such as burst communication and satellite communication. Among them, modulation and noise-adding processing includes: Double-sideband modulation is performed on the baseband signal in the first data transmission frame to obtain a modulated signal; and noise is added to the modulated signal using an optimized Gaussian channel.

[0030] Wherein, optimizing the Gaussian channel includes introducing a multipath fading channel into the Gaussian channel.

[0031] Specifically, in the embodiment of the present application, the original UW sequence is used as the pilot sequence. During the modulation process of the first data transmission frame, the amplitude change of the first UW sequence is converted into the amplitude change of the carrier signal. Since the frequency and phase characteristics of the pilot signal are fixed, they are the same as the first UW sequence received by the receiving end of the data transmission. In addition, during the data frame transmission process, due to the influence of the Doppler effect, the carrier frequency may be offset. During the transmission process, this frequency offset can be continuously estimated and corrected by frequency offset tracking to ensure carrier synchronization.

[0032] In the process of signal processing, by adding multipath fading channel to Gaussian channel, compared with single Gaussian channel processing, optimized Gaussian channel is more universal and practical, and can be applied to various data code rates and modulation methods, code rates and channel conditions, such as BPSK (binary phase shift keying), QPSK (quadrature phase shift keying), 16QAM (sixteen quadrature amplitude-phase modulation), 64QAM (sixty-four quadrature amplitude-phase modulation), etc.

[0033] Through modulation, the original UW sequence can be transmitted on different frequency bands, avoiding interference between channels and improving the anti-interference ability of the pilot sequence. The prior art usually performs noise reduction processing on the signal to improve signal quality and improve the ability to detect the target. However, the noise reduction process may cause information distortion or loss, increasing the complexity and cost of the calculation. At the same time, noise reduction processing usually needs to be optimized in a specific noise environment, and the effect is not good in some dynamic or uncertain noise environments. The present application selects noise addition processing in order to better simulate the real transmission environment, and uses the random resonance algorithm to add an appropriate amount of noise to the pilot sequence to improve the detection performance of the first UW sequence, so as to improve the anti-interference ability and frequency deviation correction ability of the overall carrier signal.

[0034] Through modulation and noise processing, the recovery capability and frequency offset estimation performance of the first UW sequence under different signal-to-noise ratios can be evaluated more accurately, which helps to evaluate its anti-interference performance and provide a dynamic optimization solution for channel environment changes.

[0035] Step 103: The receiving end detects the received second data transmission frame and determines the maximum peak position of the frequency domain signal.

[0036] In some possible implementations, step 103 may include: The receiving end extracts the second data transmission frame to obtain a first UW sequence, performs correlation calculation on the first UW sequence and the original sequence to obtain an extracted sequence, and determines the maximum peak position of the frequency domain signal according to the extracted sequence.

[0037] Specifically, the receiving end will pre-store the pilot sequence, that is, the original UW sequence. Both the receiving end and the transmitting end have pre-stored pilot sequences, that is, the original UW sequence. Among them, the second data transmission frame includes the first UW sequence and the received data sequence. The original UW sequence serves as a reference signal known to the receiving end, and the first UW sequence and the original UW sequence essentially have the same and fixed frequency and phase. Therefore, the original UW sequence and / or the first UW sequence can provide a reliable carrier synchronization reference, and subsequent frequency offset estimation is performed after relevant calculations. The traditional method of calculating the spectrum usually performs pairwise conjugate multiplication of the previous and next sample values ​​of the pilot sequence to achieve frequency offset correction. However, since the complex number operation of the Fourier transform may introduce problems such as rounding errors or overflows, it aggravates the instability of the numerical values, thereby affecting the accuracy of the results. Therefore, in an embodiment of the present application, it is only necessary to extract the first UW sequence received in the second transmission frame, perform conjugate calculations on the first UW sequence and the original UW sequence, and obtain Correlation values ​​can be used to determine the corresponding two extraction sequences. Those skilled in the art can extract the first UW sequence from the received signal, ie, the second transmission frame, according to known insertion rules of pilot sequences.

[0038] In some possible implementations, determining the maximum peak position of the frequency domain signal according to the extracted sequence may include: According to the correlation formula, the first UW sequence and the original UW sequence are correlated to obtain the extracted sequence. The correlation formula is as follows: ; In the formula, represents the correlation value between the first UW sequence at the receiving end and the original UW sequence, that is, the extracted sequence, represents the first UW sequence received, represents the original UW sequence, represents the conjugation of the original UW sequence, express The number of original UW sequences and / or first UW sequences.

[0039] In some possible implementations, determining the maximum peak position of the frequency domain signal according to the extracted sequence may include steps 1 and 2: Step 1: Based on the extraction sequence, the fast Fourier transform method is used to perform signal conversion to determine the position of the maximum power spectrum of the frequency domain signal.

[0040] In some possible implementations, step one may include steps 1.1 to 1.5.

[0041] Step 1.1, based on the extracted sequence, use the fast Fourier transform method to perform signal conversion and determine the power spectrum of the frequency domain signal.

[0042] Specifically, the time domain signal can be converted into a frequency domain signal using a fast Fourier transform method (FFT), such as by a conversion formula, which is as follows: ; In the formula, represents the frequency domain signal, represents the time domain signal, represents the number of points of the fast Fourier transform, represents the base of natural logarithms, represents the complex exponential function, represents the imaginary unit, Indicates frequency, Indicates time.

[0043] The power spectrum of the frequency domain signal is calculated using the complex value of the frequency domain signal. The power spectrum formula can be obtained by calculating the square of the absolute value of the frequency domain signal, as follows: ; In the formula, represents the power spectrum, represents the frequency domain signal, Indicates frequency The corresponding amplitude, Indicates frequency.

[0044] Step 1.2, traverse the power spectrum and determine multiple local peaks.

[0045] Step 1.3, according to the peak screening strategy, determine the maximum power spectrum and its corresponding frequency domain index from multiple local peaks; wherein the peak screening strategy includes taking the local peak with the highest correlation with the original UW sequence as the maximum power spectrum.

[0046] Specifically, after the communication signal has passed through multipath propagation, the signals of different paths will be superimposed in the frequency domain, resulting in multiple peaks in the power spectrum, interfering with the detection of the subsequent maximum peak. In addition, in a low signal-to-noise ratio environment, pseudo peaks caused by random noise may appear in the power spectrum, interfering with the judgment of the maximum peak. For this type of pseudo peak, i.e., local peak, the present application uses a peak screening strategy to screen multiple local peaks, and selects the peak with the highest correlation with the original UW sequence, i.e., the peak with a correlation value approaching 1 as the maximum power spectrum, thereby improving the accuracy of locating the subsequent maximum peak.

[0047] Step 1.4, map the frequency domain index to the frequency axis, take the position of the frequency corresponding to the maximum power spectrum as the position of the maximum power spectrum, and determine the frequency range of the frequency domain according to the position of the maximum power spectrum.

[0048] Specifically, during the transmission process, the frequency domain position of the signal will change, causing the signal's spectrum to shift on the frequency axis. The signal received by the receiver is not completely aligned with the expected signal received by the transmitter, which in turn affects the subsequent demodulation and decoding processing. The result of the fast Fourier algorithm is a complex array, in which each element represents the amplitude and phase of the frequency domain signal at the corresponding frequency. Combined with the symmetry and periodicity of the discrete Fourier transform, the frequency domain signal of the extracted sequence is decomposed into multiple smaller discrete Fourier transforms and combined for solution, thereby greatly reducing the complexity of the calculation. According to the position of the frequency corresponding to the maximum value power spectrum, it is judged that it corresponds to the frequency domain. This is to facilitate the subsequent accurate calculation of the frequency offset estimate.

[0049] Step 1.5, the maximum peak position of the frequency domain signal is the position of the maximum power spectrum.

[0050] Step 2: Determine the maximum peak position according to the position of the maximum power spectrum of the frequency domain signal.

[0051] Step 104: The receiving end determines a frequency offset estimation value according to the maximum peak position of the frequency domain signal.

[0052] Specifically, the receiving end determines the frequency offset estimation value according to the maximum peak position and the frequency offset estimation formula. The frequency offset estimation formula is as follows: ; In the formula, represents the frequency offset estimate, represents the maximum peak position, represents the sampling rate, Indicates the length of the data block. Represents the number of points of the Fast Fourier Transform.

[0053] Exemplarily, the sampling rate is set to 30.72e6 and the number of fast Fourier transform points is set to 512 during the simulation experiment.

[0054] Among them, Figure 3 As shown in FIG. 1 , the result diagram of the frequency offset estimation experiment under low signal-to-noise ratio conditions of this application is shown. Figure 3 The horizontal axis represents the residual frequency deviation range. Figure 4Compared with the result graph of the traditional frequency offset estimation experiment shown in FIG. 1 , the residual frequency offset range of the present application is shortened from ±5000 Hz to about ±1000 Hz, and the accuracy of the frequency offset estimation is significantly improved. And through the frequency offset estimation experiment provided by the present application, there is a probability of nearly 55% to keep the residual frequency offset range within ±250 Hz, and the probability of a large residual frequency offset is even smaller. In the traditional frequency offset estimation experiment, it can be seen that the range of the residual frequency offset is large, even up to about ±5000 Hz, and the probability within ±1000 Hz is about 50%, which indirectly reflects that the estimated frequency offset is very different from the actual frequency offset, and there is a significant gap with the method provided by the present application. In addition, when the method provided by the present application is used for frequency offset estimation, it can be achieved that under different signal-to-noise ratios, the probability of the estimated frequency offset being close to the actual frequency offset is greater, and the performance of the frequency offset estimation is better. Among them, the traditional frequency offset estimation experiment method is to insert a pilot frequency at the same distance in a frame of data, such as dividing a frame of data into ten equal data blocks of the same length. A pilot signal is inserted after each data block, and the conjugate sum operation is performed on each pilot signal in pairs, and then converted into an angle to obtain the corresponding frequency offset value. Finally, the average value of the frequency offset value is taken to obtain the final frequency offset estimated by the traditional frequency offset estimation method. Figure 3 and Figure 4 In the figure, the horizontal axis represents the residual frequency deviation in Hertz (Hz), and the vertical axis represents the probability distribution in (%).

[0055] Step 105: The receiving end performs deviation correction on the second data transmission frame based on the frequency offset estimation value to obtain a first data transmission frame.

[0056] In the embodiment of the present application, the frequency deviation estimation value is calculated through the data-assisted feedforward carrier synchronization working mode, and the receiving end of the data transmission can adjust the frequency of the local oscillator to correct the deviation of the second data transmission frame. The corrected frequency domain signal is closer to the data transmission frame of the transmitting end of the data transmission, that is, the first data transmission frame, thereby improving the accuracy of data demodulation.

[0057] In addition, during the transmission of the first data transmission frame, the data transmission receiving end will continue to use the pilot signal, that is, the original UW sequence, to perform carrier synchronization tracking, continuously estimate and correct the deviation of the carrier frequency, and maintain stable carrier synchronization while adapting to changes in channel conditions. This application can be applied to various code rates and modulation methods, and compared with the traditional method of frequency deviation estimation in the time domain, this application has a lower signal-to-noise ratio threshold and higher estimation accuracy.

[0058] Although the present application provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in this embodiment is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in sequence or in parallel according to the method shown in this embodiment or the accompanying drawings (for example, in a parallel processor or multi-threaded processing environment).

[0059] like Figure 5 As shown, the embodiment of the present application also provides a frequency domain carrier synchronization device 500 based on sparse pilots. The device includes: a data acquisition module 501, a data processing module 502, a frequency offset calculation module 503 and a carrier synchronization module 504, which are specifically as follows.

[0060] The data acquisition module 501 is used for the transmitting end to generate a data sequence and an original UW sequence.

[0061] The data processing module 502 is used for the transmitting end to insert the original UW sequence into the data sequence in an evenly spaced manner to obtain a first data transmission frame, and send the first data transmission frame to the receiving end; The receiving end detects the received second data transmission frame and determines the maximum peak position of the frequency domain signal.

[0062] The frequency offset calculation module 503 is used at the receiving end to determine the frequency offset estimation value according to the maximum peak position of the frequency domain signal.

[0063] The carrier synchronization module 504 is used for the receiving end to perform deviation correction on the second data transmission frame based on the frequency offset estimation value to obtain the first data transmission frame.

[0064] Some modules in the apparatus described in the present application can be described in the general context of computer executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0065] The devices or modules described in the above application embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described in various modules according to their functions. When implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0066] The methods, devices or modules described in this application can be implemented in the form of computer-readable program codes. The controller can be implemented in any appropriate manner. For example, the controller can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program codes (such as software or firmware) that can be executed by the (micro)processor, logic gates, switches, application-specific integrated circuits (English: Application Specific Integrated Circuit; Abbreviation: ASIC), programmable logic controllers and embedded microcontrollers. Examples of controllers include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program codes, the controller can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, this controller can be considered as a hardware component, and the devices included in it for implementing various functions can also be regarded as structures within the hardware component. Or even, the means for realizing various functions may be regarded as both a software module for realizing the method and a structure within a hardware component.

[0067] An embodiment of the present application also provides a device for executing a frequency domain carrier synchronization method based on sparse pilot, the device comprising: a processor; a memory for storing processor executable instructions; when the processor executes the executable instructions, the method described in the embodiment of the present application is implemented.

[0068] The embodiments of the present application also provide a non-volatile computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed, the method described in the embodiments of the present application is implemented.

[0069] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist independently, or two or more modules may be integrated into one module.

[0070] The above storage media include but are not limited to random access memory (RAM), read-only memory (ROM), cache, hard disk drive (HDD) or memory card. The memory can be used to store computer program instructions.

[0071] It can be seen from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary hardware. Based on this understanding, the technical solution of the present application can be essentially or partly reflected in the prior art in the form of a software product, or it can be reflected in the implementation process of data migration. The computer software product can be stored in a storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0072] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. All or part of this application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc.

[0073] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A frequency domain carrier synchronization method based on sparse pilot, characterized in that: include: The transmitter generates a data sequence and an original UW sequence; The transmitting end inserts the original UW sequence into the data sequence in a post-positioned manner at equal intervals to obtain a first data transmission frame, and sends the first data transmission frame to the receiving end; The receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal; The receiving end determines a frequency offset estimation value according to the maximum peak position of the frequency domain signal; The receiving end performs deviation correction on the second data transmission frame based on the frequency offset estimation value to obtain the first data transmission frame.

2. The method according to claim 1, characterized in that After the transmitting end inserts the original UW sequence into the data sequence in an evenly spaced post-position manner to obtain a first data transmission frame, the method further includes: Performing modulation and noise adding processing on the first data transmission frame; The modulation and noise adding process includes: Performing double-sideband modulation on the baseband signal in the first data transmission frame to obtain a modulated signal; Noise is added to the modulated signal using an optimized Gaussian channel; wherein the optimized Gaussian channel includes introducing a multipath fading channel into the Gaussian channel.

3. The method according to claim 1, characterized in that The receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal, including: The receiving end extracts the second data transmission frame to obtain a first UW sequence; Performing correlation calculation on the first UW sequence and the original UW sequence to obtain an extracted sequence; The maximum peak position of the frequency domain signal is determined according to the extraction sequence.

4. The method according to claim 3, characterized in that The performing correlation calculation on the first UW sequence and the original UW sequence to obtain an extracted sequence includes: According to a correlation formula, correlation calculation is performed on the first UW sequence and the original UW sequence to obtain an extracted sequence; the correlation formula is as follows: ； In the formula, represents a correlation value between the first received UW sequence and the original UW sequence, that is, the extracted sequence, represents the first UW sequence received, represents the original UW sequence, represents taking the conjugate of the original UW sequence, Indicates the number of the first UW sequence and the original UW sequence.

5. The method according to claim 3, characterized in that: Determining the maximum peak position of the frequency domain signal according to the extraction sequence includes: Based on the extraction sequence, a fast Fourier transform method is used to perform signal conversion to determine the position of the maximum power spectrum of the frequency domain signal; The maximum peak position is determined according to the position of the maximum value power spectrum of the frequency domain signal.

6. The method according to claim 5, characterized in that The method of performing signal conversion based on the extraction sequence using a fast Fourier transform method to determine the position of the maximum power spectrum of the frequency domain signal includes: Based on the extraction sequence, a fast Fourier transform method is used to perform signal conversion to determine the power spectrum of the frequency domain signal; Traversing the power spectrum to determine a plurality of local peaks; According to the peak screening strategy, the maximum power spectrum and its corresponding frequency domain index are determined from the multiple local peaks; wherein the peak screening strategy includes taking the local peak with the highest correlation with the original UW sequence as the maximum power spectrum; Mapping the frequency domain index to the frequency axis, taking the position of the frequency corresponding to the maximum value power spectrum as the position of the maximum value power spectrum, and determining the frequency range of the frequency domain according to the position of the maximum value power spectrum; The maximum peak position of the frequency domain signal is the position of the maximum value power spectrum.

7. The method according to claim 1, characterized in that The receiving end determines a frequency offset estimation value according to the maximum peak position, including: The receiving end determines the frequency offset estimation value according to the maximum peak position and a frequency offset estimation formula; the frequency offset estimation formula is as follows: ； In the formula, represents the frequency offset estimation value, represents the maximum peak position, represents the sampling rate, Indicates the length of the data block. Represents the number of points of the Fast Fourier Transform.

8. A device for frequency domain carrier synchronization based on sparse pilot, characterized in that: include: Data acquisition module, used for generating data sequence and original UW sequence at the transmitting end; A data processing module, configured for the transmitting end to insert the original UW sequence into the data sequence in an evenly spaced post-position manner to obtain a first data transmission frame, and to send the first data transmission frame to the receiving end; The receiving end detects the received second data transmission frame to determine the maximum peak position of the frequency domain signal; A frequency offset calculation module, configured for the receiving end to determine a frequency offset estimation value according to the maximum peak position of the frequency domain signal; The carrier synchronization module is used for the receiving end to perform deviation correction on the second data transmission frame based on the frequency offset estimation value to obtain the first data transmission frame.

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