Method, device and electronic device for estimating sampling frequency deviation without data assistance

Abstract

The present invention provides a method, device, and electronic device for estimating sampling frequency deviation without data assistance, which can be applied to the field of wireless communication technology. The method for estimating sampling frequency deviation without data assistance includes: extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal in response to receiving an orthogonal frequency division multiplexing signal; performing discrete Fourier transform processing on multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; obtaining a phase change rate corresponding to each orthogonal frequency division multiplexing symbol based on the frequency domain values of the multiple subcarriers; performing minimum mean square error estimation processing on the phase change rates corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; and calculating a target sampling frequency deviation based on the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more particularly to a method, device and electronic device for estimating sampling frequency deviation without data assistance. Background Art

[0002] Orthogonal frequency division multiplexing (OFDM), a multi-carrier technology, is widely used in digital broadcasting, wireless access networks, satellite communications, and other fields. When a transmitter sends an OFDM signal to a receiver, the crystal oscillators on the two ends may not be fully matched, resulting in errors in the received OFDM signal, affecting subsequent information extraction.

[0003] In the process of realizing the above-mentioned inventive concept, it was found that in the related technology, due to the inconsistent vibration frequency of the crystal oscillators at the transmitting and receiving ends, there was a sampling frequency error in the process of processing the received orthogonal frequency division multiplexing signal at the receiving end, thereby affecting the orthogonality between the subcarriers in the orthogonal frequency division multiplexing symbols, resulting in interference between the subcarriers and reducing the transmission performance of the system. Technical problem. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method, device and electronic device for estimating sampling frequency deviation without data assistance.

[0005] According to a first aspect of the present invention, a non-data-assisted method for estimating sampling frequency deviation is provided, comprising: in response to receiving an orthogonal frequency division multiplexing signal, extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal, wherein the orthogonal frequency division multiplexing symbol includes multiple data symbols and a cyclic prefix symbol; performing discrete Fourier transform processing on multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; obtaining a phase change rate corresponding to each orthogonal frequency division multiplexing symbol based on the frequency domain values of the multiple subcarriers; performing minimum mean square error estimation processing on the phase change rate corresponding to at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; and calculating a target sampling frequency deviation based on the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

[0006] According to an embodiment of the present invention, in response to receiving an orthogonal frequency division multiplexing signal, at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal, including: obtaining the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol, and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal; determining the first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol based on the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol, and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal, wherein the first orthogonal time period represents that all sampling points within the first orthogonal time period of the orthogonal frequency division multiplexing signal are sampling points included in any one orthogonal frequency division multiplexing symbol; based on multiple first orthogonal time periods, at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal.

[0007] According to an embodiment of the present invention, discrete Fourier transform processing is performed on multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol, including: extracting multiple sampling point signals corresponding to the sampling points from each orthogonal frequency division multiplexing symbol according to a first predetermined condition; and performing discrete Fourier transform processing on the multiple sampling point signals respectively to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol.

[0008] According to an embodiment of the present invention, the first predetermined condition is constructed based on a clock period and a sequence number of sampling points used by the transmitting end to transmit an orthogonal frequency division multiplexing signal.

[0009] According to an embodiment of the present invention, a phase change rate corresponding to each orthogonal frequency division multiplexing symbol is obtained based on frequency domain values of multiple subcarriers, including: for any one of the multiple orthogonal frequency division multiplexing symbols, obtaining the subcarrier phase corresponding to each subcarrier from the frequency domain values of multiple subcarriers corresponding to any one of the orthogonal frequency division multiplexing symbols; determining the sampling point phase corresponding to each sampling point based on the subcarrier phase corresponding to each subcarrier; calculating based on the multiple sampling point phases to obtain the phase change rate corresponding to any one of the orthogonal frequency division multiplexing symbols; performing the above operation on each of the multiple orthogonal frequency division multiplexing symbols to obtain the phase change rate corresponding to each orthogonal frequency division multiplexing symbol.

[0010] According to an embodiment of the present invention, minimum mean square error estimation processing is performed on the phase change rate corresponding to at least three orthogonal frequency division multiplexing symbols to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal, including: constructing a phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal based on the phase change rate corresponding to each orthogonal frequency division multiplexing symbol in the at least three orthogonal frequency division multiplexing symbols; based on a predetermined relationship between the phase change rate and the sampling clock deviation, the phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal is processed according to the ordinal matrix and noise parameters of each orthogonal frequency division multiplexing symbol to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal.

[0011] According to an embodiment of the present invention, the target sampling frequency deviation is calculated based on the clock deviation change rate, including: obtaining the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal based on the clock deviation change rate; and calculating the target sampling frequency deviation based on the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal based on a predetermined relationship between the sampling clock deviation and the sampling frequency deviation.

[0012] According to an embodiment of the present invention, the method also includes: obtaining a transmission sampling frequency for transmitting an orthogonal frequency division multiplexing signal; calculating a target sampling frequency based on the sampling frequency deviation and the transmission sampling frequency; and resampling the orthogonal frequency division multiplexing signal using the target sampling frequency to obtain a target orthogonal frequency division multiplexing signal.

[0013] The second aspect of the present invention provides a non-data-assisted device for estimating sampling frequency deviation, comprising: an extraction module for extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal in response to receiving an orthogonal frequency division multiplexing signal, wherein the orthogonal frequency division multiplexing signal includes multiple orthogonal frequency division multiplexing symbols and a cyclic prefix symbol; a frequency domain value obtaining module for performing discrete Fourier transform processing on multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; a phase change rate obtaining module for obtaining the phase change rate corresponding to each orthogonal frequency division multiplexing symbol based on the frequency domain values of multiple subcarriers; a clock deviation obtaining module for performing minimum mean square error estimation processing on the phase change rate corresponding to at least three orthogonal frequency division multiplexing symbols to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; and a frequency deviation obtaining module for calculating the target sampling frequency deviation based on the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

[0014] A third aspect of the present invention provides an electronic device comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors execute the above method.

[0015] A fourth aspect of the present invention further provides a computer-readable storage medium having executable instructions stored thereon, which, when executed by a processor, causes the processor to execute the above method.

[0016] The fifth aspect of the present invention further provides a computer program product, comprising a computer program, which implements the above method when executed by a processor.

[0017] According to the non-data-assisted method, device and electronic device for estimating sampling frequency deviation of the present invention, in response to receiving an orthogonal frequency division multiplexing signal, at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal, a discrete Fourier transform is performed on a plurality of subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of a plurality of subcarriers corresponding to each orthogonal frequency division multiplexing symbol, a phase change rate corresponding to each orthogonal frequency division multiplexing symbol is obtained based on the frequency domain values of the plurality of subcarriers, a minimum mean square error estimation process is performed on the phase change rate corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; based on the clock deviation The target sampling frequency deviation is calculated based on the phase change rate, which eliminates the problems of unclear demodulation constellation diagram and inter-carrier interference caused by the frequency deviation due to the clock asynchrony between the transmitting and receiving ends. It is realized that only the phase change rate between the three orthogonal frequency division multiplexing symbols can be used to accurately obtain the target sampling frequency deviation corresponding to the orthogonal frequency division multiplexing signal for sampling processing, thereby improving the accuracy of the obtained sampling frequency deviation. The sampling frequency is compensated according to the obtained accurate target sampling frequency deviation, so as to obtain an accurate sampling frequency, so as to facilitate sampling of the orthogonal frequency division multiplexing signal and obtain error-free signal information without inter-carrier interference, thereby improving the processing efficiency of the signal processing system.

[0018] According to an embodiment of the present invention, further, the orthogonal frequency division multiplexing signal of the present invention only includes multiple orthogonal frequency division multiplexing symbols and cyclic prefix symbols, and the cyclic prefix symbol is only used to distinguish two adjacent orthogonal frequency division multiplexing symbols or two adjacent orthogonal frequency division multiplexing signals, so that the receiving end can facilitate sampling and processing, and there is no need to determine the target sampling frequency deviation based on reference symbols such as pilot symbols and training symbols, thereby achieving the improvement of signal utilization and spectrum utilization of the orthogonal frequency division multiplexing signal, and making the orthogonal frequency division multiplexing signal have lower complexity, so as to improve the processing efficiency of the receiving end, reduce processing energy consumption, and improve the reliability of signal processing, so that it can be applicable to orthogonal frequency division multiplexing signals of various specifications, reduce processing costs while maintaining high efficiency and flexibility of processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A diagram showing an application scenario of a non-data-assisted method for estimating a sampling frequency deviation according to an embodiment of the present invention;

[0021] Figure 2 A flow chart of a method for estimating sampling frequency deviation without data assistance according to an embodiment of the present invention is shown;

[0022] Figure 3 A schematic diagram showing a sampling frequency deviation according to an embodiment of the present invention is shown;

[0023] Figure 4a FIG2 shows a schematic diagram of a constellation after demodulation of the second orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0024] Figure 4b shows a schematic diagram of a constellation after demodulation of the 12th orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0025] Figure 4c FIG2 shows a schematic diagram of a constellation after demodulation of the 42nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0026] Figure 4d FIG2 shows a schematic diagram of a constellation after demodulation of the 82nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0027] Figure 5a A schematic diagram showing a phase change of a second orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0028] Figure 5b A schematic diagram showing a phase change of a 12th orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0029] Figure 5c A schematic diagram showing a phase change of a 42nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention is shown;

[0030] Figure 5d A schematic diagram showing a phase change of the 82nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention;

[0031] Figure 6 A schematic diagram showing phase change rates of multiple orthogonal frequency division multiplexing symbols according to an embodiment of the present invention is shown;

[0032] Figure 7a A schematic diagram showing a signal phase without compensating for sampling frequency deviation according to an embodiment of the present invention;

[0033] Figure 7bA schematic diagram showing a signal phase compensated for sampling frequency deviation by a method according to an embodiment of the present invention is shown;

[0034] Figure 8a A schematic diagram of a constellation after demodulation of the second orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown;

[0035] Figure 8b A schematic diagram of a constellation after demodulation of the 12th orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown;

[0036] Figure 8c A schematic diagram of a constellation after demodulation of the 42nd orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown;

[0037] Figure 8d A schematic diagram of a constellation after demodulation of the 82nd orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown;

[0038] Figure 9 A structural block diagram of a non-data-assisted device for estimating sampling frequency deviation according to an embodiment of the present invention is shown;

[0039] Figure 10 A block diagram of an electronic device showing a non-data-aided method for estimating sampling frequency deviation according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0041] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0042] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0043] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0044] In the technical solution of the present invention, the user information involved (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, invention and application of the relevant data comply with relevant laws, regulations and standards, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0045] Orthogonal frequency division multiplexing (OFDM), as a multi-carrier technology, has been widely adopted in fields such as digital broadcasting, wireless access networks, and satellite communications. It is a key technology for next-generation wireless communication systems. However, because the crystal oscillators at the transmitter and receiver cannot be perfectly matched, sampling frequency offset (SFO) is inevitable between the two ends. This sampling frequency offset can destroy the orthogonality between subcarriers in an OFDM system, leading to inter-carrier interference (ICI).

[0046] In order to solve the sampling frequency error existing at both ends of the transmitter and receiver, the existing technology estimates the sampling frequency error through the data-assisted method. The data-assisted method estimates the sampling clock at the receiving end by designing a pilot sequence with a special structure, and by introducing a specific reference signal, the receiving end can accurately estimate the sampling frequency deviation, thereby effectively reducing the impact of inter-carrier interference. However, estimating the sampling frequency error using the data-assisted method requires a large number of reference symbols, and the accuracy of the estimated sampling frequency error is low. In the process of realizing the above-mentioned inventive concept, it was found that in the related technology, due to the inconsistent vibration frequency of the crystal oscillator at both ends of the transmitter and receiver, the receiving end has a sampling frequency error in the process of processing the received orthogonal frequency division multiplexing signal, thereby affecting the orthogonality between the subcarriers in the orthogonal frequency division multiplexing symbol, resulting in interference between subcarriers and reducing the transmission performance of the system.

[0047] In view of this, an embodiment of the present invention provides a non-data-assisted method for estimating sampling frequency deviation, comprising: in response to receiving an orthogonal frequency division multiplexing signal, extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal, wherein the orthogonal frequency division multiplexing symbol includes multiple data symbols and a cyclic prefix symbol; performing discrete Fourier transform processing on the multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; obtaining a phase change rate corresponding to each orthogonal frequency division multiplexing symbol based on the frequency domain values of the multiple subcarriers; performing minimum mean square error estimation processing on the phase change rate corresponding to at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; and calculating a target sampling frequency deviation based on the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

[0048] Figure 1 A diagram showing an application scenario of a non-data-assisted method for estimating a sampling frequency deviation according to an embodiment of the present invention is shown.

[0049] like Figure 1 As shown, the application scenario according to this embodiment may include a first signal device 101, a second signal device 102, and a terminal device 103. The first signal device 101 is configured to send an orthogonal frequency division multiplexing signal to the second signal device 102.

[0050] The user may use the first signaling device 101 to interact with the second signaling device 102 to obtain corresponding signal information, etc. The first wireless device 101 may be a sending device that sends a signal.

[0051] The terminal device 103 can analyze and process data such as signal information sent by the first signal device 101.

[0052] The second signal device 102 is a mobile signal device that can send signals to the first signal device 101 and can also receive signals and other data sent by the first signal device 101.

[0053] It should be noted that the non-data-assisted method for estimating the sampling frequency deviation provided in the embodiment of the present invention can generally be performed by the terminal device 103. Accordingly, the non-data-assisted apparatus for estimating the sampling frequency deviation provided in the embodiment of the present invention can generally be set in the terminal 103. The non-data-assisted method for estimating the sampling frequency deviation provided in the embodiment of the present invention can also be performed by the first signal device 101 and the second signal device 102, or a cluster of signal devices, which are different from the terminal device 103. Accordingly, the non-data-assisted apparatus for estimating the sampling frequency deviation provided in the embodiment of the present invention can also be set in the first signal device 101 and the second signal device 102, or a cluster of signal devices, which are different from the terminal device 103.

[0054] It should be understood that Figure 1 The number of terminal devices in the embodiment is merely illustrative. Any number of terminal devices may be provided according to implementation requirements.

[0055] The following will be based on Figure 1 The scene described by Figure 2 to Figure 8d The non-data-assisted method for estimating sampling frequency deviation according to an embodiment of the present invention is described in detail.

[0056] Figure 2 A flow chart of a method for estimating sampling frequency deviation without data assistance according to an embodiment of the present invention is shown.

[0057] like Figure 2 As shown, the non-data-assisted method for estimating sampling frequency deviation in this embodiment includes operations S210 to S250.

[0058] In operation S210, in response to receiving an OFDM signal, at least three OFDM symbols are extracted from the OFDM signal.

[0059] According to an embodiment of the present invention, the OFDM signal received by the receiving end may be an OFDM signal sampled at a sampling frequency including a sampling frequency error, that is, a sampling period including a sampling clock deviation. The sampling period including the sampling clock deviation may be as shown in formula (1).

[0060] T S '=(1+△T S )·T S (1)

[0061] Among them, T S ' can be represented as the actual sampling period of the receiving end, △T S It can be characterized as the sampling clock deviation, T S It can be characterized as the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal.

[0062] According to an embodiment of the present invention, an orthogonal frequency division multiplexing symbol includes a plurality of data symbols and a cyclic prefix symbol.

[0063] According to an embodiment of the present invention, a transmitting end transmits an orthogonal frequency division multiplexing signal to a receiving end. A frame of an orthogonal frequency division multiplexing signal may include multiple orthogonal frequency division multiplexing symbols, and an orthogonal frequency division multiplexing symbol may include multiple data symbols. An orthogonal frequency division multiplexing symbol may include multiple subcarriers. In addition to data symbols, an orthogonal frequency division multiplexing symbol may also include a cyclic prefix symbol. Since the method for estimating the sampling frequency deviation of the present invention does not require the use of a cyclic prefix symbol for estimation, an orthogonal frequency division multiplexing symbol may include only one cyclic prefix symbol, or may not include a cyclic prefix symbol. The cyclic prefix symbol may be used to distinguish two adjacent orthogonal frequency division multiplexing symbols.

[0064] According to an embodiment of the present invention, only three orthogonal frequency division multiplexing symbols can be used to calculate the target sampling frequency error corresponding to the orthogonal frequency division multiplexing signal, all orthogonal frequency division multiplexing symbols can be used to calculate the target sampling frequency error corresponding to the orthogonal frequency division multiplexing signal, and only two orthogonal frequency division multiplexing symbols can be used to calculate the target sampling frequency error corresponding to the orthogonal frequency division multiplexing signal. When all orthogonal frequency division multiplexing symbols are used to calculate the target sampling frequency error, the estimated sampling frequency error has high accuracy. When only three orthogonal frequency division multiplexing symbols are used to calculate the target sampling frequency error, the estimated sampling frequency error has high accuracy and efficiency, and the estimation time is short. When only two orthogonal frequency division multiplexing symbols are used to calculate the target sampling frequency error, the estimated sampling frequency error has low accuracy compared to using three or more orthogonal frequency division multiplexing symbols, but the estimation efficiency is high and the estimation time is short.

[0065] In operation S220, a discrete Fourier transform process is performed on the multiple subcarriers included in each OFDM symbol to obtain frequency domain values of the multiple subcarriers corresponding to each OFDM symbol.

[0066] According to an embodiment of the present invention, an OFDM symbol includes multiple subcarriers, the number of sampling points of the OFDM symbol is M, and the number of sampling points of the data symbol is N. sub , the number of sampling points of the cyclic prefix symbol is N G The sum of the number of sampling points of the data symbol and the number of sampling points of the cyclic prefix symbol is the number of sampling points of the OFDM symbol, that is, M=N sub +N G , the number of fast Fourier transform points used for demodulation is N.

[0067] According to an embodiment of the present invention, discrete Fourier transform processing is performed on the orthogonal frequency division multiplexing symbols in the time domain form so that the orthogonal frequency division multiplexing symbols are converted into orthogonal frequency division multiplexing symbols in the frequency domain form, thereby obtaining the frequency domain values of the subcarriers included in the orthogonal frequency division multiplexing symbols.

[0068] In operation S230, a phase change rate corresponding to each orthogonal frequency division multiplexing symbol is obtained according to frequency domain values of the plurality of subcarriers.

[0069] According to an embodiment of the present invention, the frequency domain value of the subcarrier includes phase information corresponding to the subcarrier.

[0070] According to an embodiment of the present invention, the phase change rate corresponding to the orthogonal frequency division multiplexing symbol including the subcarriers is calculated based on the phase information corresponding to the subcarriers.

[0071] In operation S240, a minimum mean square error estimation process is performed on the phase change rates corresponding to at least three OFDM symbols to obtain a clock deviation change rate corresponding to the OFDM signal.

[0072] According to an embodiment of the present invention, the phase change rate corresponding to the three orthogonal frequency division multiplexing symbols in the orthogonal frequency division multiplexing signal can be processed, and the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal can be obtained based on the condition that the three orthogonal frequency division multiplexing symbols and the orthogonal frequency division multiplexing signal have a consistent clock deviation change rate.

[0073] In operation S250 , a target sampling frequency deviation is calculated according to the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

[0074] According to an embodiment of the present invention, based on the clock deviation change rate and the relationship between the clock deviation change rate and the sampling frequency deviation, the target sampling frequency deviation is calculated, and based on the target sampling frequency deviation, the sampling frequency of the orthogonal frequency division multiplexing signal is adjusted, so that the receiving end can receive the orthogonal frequency division multiplexing signal that eliminates the inter-carrier interference caused by the clock asynchrony between the transmitting and receiving ends.

[0075] According to an embodiment of the present invention, in response to receiving an orthogonal frequency division multiplexing signal, at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal, a discrete Fourier transform is performed on a plurality of subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of a plurality of subcarriers corresponding to each orthogonal frequency division multiplexing symbol, a phase change rate corresponding to each orthogonal frequency division multiplexing symbol is obtained based on the frequency domain values of the plurality of subcarriers, a minimum mean square error estimation is performed on the phase change rate corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; and a target acquisition signal is obtained by calculation based on the clock deviation change rate. The sampling frequency deviation eliminates the problems of unclear demodulation constellation diagram and inter-carrier interference caused by the frequency deviation due to the clock asynchrony between the transmitting and receiving ends, and realizes that only the phase change rate between the three orthogonal frequency division multiplexing symbols can be used to accurately obtain the target sampling frequency deviation corresponding to the orthogonal frequency division multiplexing signal for sampling processing, thereby improving the accuracy of the obtained sampling frequency deviation, and compensating the sampling frequency according to the obtained accurate target sampling frequency deviation to obtain an accurate sampling frequency, so as to facilitate sampling of the orthogonal frequency division multiplexing signal and obtain error-free signal information without inter-carrier interference, thereby improving the processing efficiency of the signal processing system.

[0076] According to an embodiment of the present invention, further, the orthogonal frequency division multiplexing symbols of the present invention only include multiple data symbols and cyclic prefix symbols, and the cyclic prefix symbol is only used to distinguish two adjacent orthogonal frequency division multiplexing symbols, so that the receiving end can facilitate sampling and processing, and there is no need to determine the target sampling frequency deviation based on reference symbols such as pilot symbols and training symbols, thereby achieving the improvement of signal utilization and spectrum utilization of the orthogonal frequency division multiplexing signal, and making the orthogonal frequency division multiplexing signal have lower complexity, so as to improve the processing efficiency of the receiving end, reduce processing energy consumption, and improve the reliability of signal processing, so that it can be applicable to orthogonal frequency division multiplexing signals of various specifications, reduce processing costs while maintaining high efficiency and flexibility of processing.

[0077] According to an embodiment of the present invention, in response to receiving an OFDM signal, a method of extracting at least three OFDM symbols from the OFDM signal includes the following operations.

[0078] According to an embodiment of the present invention, the number of sampling points of an OFDM symbol, the number of sampling points of a cyclic prefix symbol, and a clock period used by a transmitter to transmit an OFDM signal are obtained.

[0079] According to an embodiment of the present invention, any sampling point signal in any OFDM symbol in an OFDM signal received by a receiving end can be expressed as shown in formula (2).

[0080] (2)

[0081] Among them, y m (n) can be represented as the nth sampling point signal in the mth OFDM symbol in the time domain OFDM signal received by the receiver, x() can be represented as the time domain OFDM signal transmitted by the transmitter, m can be represented as the ordinal number of the selected OFDM symbol, n can be represented as the ordinal number of the selected sampling point, M can be represented as the number of sampling points of the OFDM symbol, N G It can be represented as the number of sampling points of the cyclic prefix symbol, T S ' can be represented as the actual sampling period of the receiving end, △T S It can be characterized as the sampling clock deviation, T S It can be characterized as the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal.

[0082] According to an embodiment of the present invention, the first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol is determined based on the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal.

[0083] According to an embodiment of the present invention, the first orthogonal time period represents that all sampling points in the first orthogonal time period of the orthogonal frequency division multiplexing signal are sampling points included in any one orthogonal frequency division multiplexing symbol.

[0084] According to an embodiment of the present invention, the first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol is determined according to the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the data symbol, and the clock period of the transmitted signal. The first orthogonal time period can be expressed as formula (3).

[0085] (3)

[0086] Among them, t can be characterized as the first orthogonal time corresponding to an orthogonal frequency division multiplexing (OFDM) symbol, and A can be characterized as the total number of OFDM symbols in the OFDM signal. According to the inequality, the first orthogonal period in which the first orthogonal time is located can be obtained. Multiple first orthogonal periods can be obtained according to the different ordinal numbers of the symbols. For example, if the number of sampling points of the OFDM signal is 100, the number of sampling points of the cyclic prefix symbol is 5, and the clock used by the transmitter to transmit the OFDM signal is 1 s, then the first orthogonal period corresponding to the first OFDM symbol is 5 s < t < 100 s, the first orthogonal period corresponding to the second OFDM symbol is 105 s < t < 200 s, and the first orthogonal period corresponding to the fifth OFDM symbol is 405 s < t < 500 s. According to an embodiment of the present invention, since the OFDM symbol further includes a prefix cyclic symbol, the OFDM symbol can be demodulated, so as to remove the prefix cyclic symbol and only retain the data symbol, enabling the receiving end to analyze and process the data symbol carrying information such as subcarriers to obtain the required information.

[0087] According to an embodiment of the present invention, based on multiple first orthogonal periods, at least three OFDM symbols are extracted from the OFDM signal.

[0088] According to an embodiment of the present invention, through multiple first orthogonal periods, any three OFDM symbols can be extracted from the OFDM signal.

[0089] According to an embodiment of the present invention, any OFDM symbol received by the receiving end from the transmitting end can be represented as shown in formula (4).

[0090] (4)

[0091] Where, x m (t)can be characterized as the m-th OFDM symbol extracted from the OFDM signal in the time domain form, k can be characterized as the k-th subcarrier on the OFDM signal transmitted by the transmitting end, N can be characterized as the number of points of the fast Fourier transform (FFT) used for demodulation, and N sub can be characterized as the number of sampling points of the data symbol.

[0092] According to an embodiment of the present invention, three OFDM symbols can be extracted from the OFDM signal, so as to reduce the calculation amount and improve the processing efficiency, and at the same time, the accurate target sampling frequency deviation can be estimated according to the three OFDM symbols.

[0093] According to an embodiment of the present invention, by obtaining the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal, the first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol is determined according to the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal, and based on multiple first orthogonal time periods, at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal, thereby achieving accurate extraction of at least three orthogonal frequency division multiplexing symbols, so as to facilitate estimation of an accurate target sampling frequency deviation based on the at least three orthogonal frequency division multiplexing symbols. Since the present invention does not need to extract the target sampling frequency deviation based on the cyclic prefix symbol, the signal utilization and processing efficiency can be improved.

[0094] According to an embodiment of the present invention, a method for performing discrete Fourier transform processing on multiple subcarriers included in each orthogonal frequency division multiplexing symbol to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol includes the following operations.

[0095] According to an embodiment of the present invention, a plurality of sampling point signals corresponding to the sampling points are extracted from each orthogonal frequency division multiplexing symbol according to a first predetermined condition.

[0096] According to an embodiment of the present invention, the first predetermined condition is constructed based on the clock period and the sequence number of the sampling points used by the transmitting end to transmit the orthogonal frequency division multiplexing signal. The first predetermined condition can be expressed according to formula (5).

[0097] (5)

[0098] The first predetermined condition can be n and T s The product of .

[0099] According to an embodiment of the present invention, the sampling point signal extracted from the orthogonal frequency division multiplexing symbol can be expressed as formula (6).

[0100] (6)

[0101] Among them, x m (n) can be represented as the nth sampling point signal in the mth OFDM symbol in the transmitted signal in the time domain form, X m (k) may be represented as a frequency domain value of a k-th subcarrier included in an m-th OFDM symbol of an OFDM signal carried in a frequency domain form of a transmission signal.

[0102] According to an embodiment of the present invention, based on any one of the above sampling point signals, a plurality of sampling point signals corresponding to different sampling points are extracted according to different sampling points.

[0103] According to an embodiment of the present invention, discrete Fourier transform processing is performed on the multiple sampling point signals respectively to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol.

[0104] According to an embodiment of the present invention, based on the second predetermined condition, a time-domain-frequency domain transformation method is used to perform discrete Fourier transform processing on multiple sampling point signals in the same orthogonal frequency division multiplexing symbol in the time domain to obtain a frequency domain value of each subcarrier in the same orthogonal frequency division multiplexing symbol in the frequency domain. The same operation is then performed on at least three orthogonal frequency division multiplexing symbols to obtain a frequency domain value of each subcarrier in each orthogonal frequency division multiplexing symbol in the frequency domain.

[0105] According to an embodiment of the present invention, the second predetermined condition can be characterized as follows: in the mth orthogonal frequency division multiplexing symbol, multiple sampling points in the orthogonal frequency division multiplexing symbol and multiple subcarriers in the orthogonal frequency division multiplexing symbol are in a one-to-one correspondence, that is, the number of sampling points is equal to the number of subcarriers.

[0106] According to an embodiment of the present invention, the frequency domain value of any subcarrier in an orthogonal frequency division multiplexing symbol can be expressed as formula (7).

[0107] (7)

[0108] Among them, Y m (l) can be represented as the frequency domain value of the lth subcarrier included in the mth OFDM symbol of the received OFDM signal in the frequency domain form, X m (k) can be represented as the frequency domain value of the kth subcarrier included in the mth orthogonal frequency division multiplexing symbol of the orthogonal frequency division multiplexing signal carried in the frequency domain form of the transmitted signal, l can be represented as the lth subcarrier on the received orthogonal frequency division multiplexing signal, and k can be represented as the kth subcarrier on the transmitted orthogonal frequency division multiplexing signal. l and k are in a corresponding relationship, and l and k are only used to distinguish the subcarriers sent by the receiving end from the subcarriers sent by the transmitting end.

[0109] According to an embodiment of the present invention, the frequency domain value of any subcarrier in the orthogonal frequency division multiplexing symbol in formula (7) is processed according to the third predetermined condition to obtain the frequency domain value of the subcarrier. The third predetermined condition can be expressed as formula (8), and the frequency domain value of the processed subcarrier can be expressed as formula (9).

[0110] (8)

[0111] Among them, A can be represented as a total of A orthogonal frequency division multiplexing symbols in the orthogonal frequency division multiplexing signal, and else can be represented as not meeting In the case where the product of the ordinal number of the kth subcarrier on the transmitted OFDM signal minus the ordinal number of the lth subcarrier on the received OFDM signal and the ordinal number of the mth OFDM symbol multiplied by the number of sampling points of the OFDM symbol is equal, let is the number of fast Fourier transform points used for demodulation, otherwise let is 0.

[0112] (9)

[0113] Among them, Y m (l) can be represented as the frequency domain value of the lth subcarrier included in the mth OFDM symbol of the received OFDM signal in the frequency domain form, X m (l) can be represented as the frequency domain value of the lth subcarrier included in the mth OFDM symbol of the OFDM signal carried in the frequency domain form of the transmitted signal.

[0114] According to the embodiment of the present invention, the frequency domain values may be calculated for some subcarriers in an OFDM symbol, or may be calculated for all subcarriers in an OFDM symbol.

[0115] According to the embodiment of the present invention, the above-mentioned operation is performed on each OFDM symbol to obtain frequency domain values of multiple subcarriers corresponding to each OFDM symbol.

[0116] According to an embodiment of the present invention, by constructing a first predetermined condition based on a clock period and an ordinal number of sampling points used by a transmitter to transmit an orthogonal frequency division multiplexing signal, multiple sampling point signals corresponding to the sampling points are extracted from each orthogonal frequency division multiplexing symbol, and discrete Fourier transform processing is performed on the multiple sampling point signals to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol. This achieves the purpose of obtaining a received orthogonal frequency division multiplexing signal based on the transmitted orthogonal frequency division multiplexing signal and obtaining the frequency domain values of the subcarriers in the orthogonal frequency division multiplexing symbol in frequency domain form, so as to obtain a phase change rate based on the frequency domain values of the subcarriers. Furthermore, it is also possible to obtain only the frequency domain values of some subcarriers in an orthogonal frequency division multiplexing symbol, thereby improving the processing efficiency of the system while ensuring error accuracy.

[0117] According to an embodiment of the present invention, a method for obtaining a phase change rate corresponding to each orthogonal frequency division multiplexing symbol according to frequency domain values of multiple subcarriers includes the following operations.

[0118] According to an embodiment of the present invention, for any one of a plurality of OFDM symbols, a subcarrier phase corresponding to each subcarrier is obtained from frequency domain values of a plurality of subcarriers corresponding to the any one OFDM symbol.

[0119] According to an embodiment of the present invention, the subcarrier phase may be expressed as shown in formula (10).

[0120] (10)

[0121] Among them, p m (l) can be represented as the subcarrier phase of the l-th subcarrier included in the m-th OFDM symbol.

[0122] According to an embodiment of the present invention, a sampling point phase corresponding to each sampling point is determined according to a subcarrier phase corresponding to each subcarrier.

[0123] According to the embodiment of the present invention, based on the second predetermined condition, since subcarriers and sampling points correspond one-to-one, the sampling point phase corresponding to each sampling point can be determined based on the subcarrier phase corresponding to each subcarrier.

[0124] According to an embodiment of the present invention, calculation is performed based on the phases of multiple sampling points to obtain the phase change rate corresponding to any orthogonal frequency division multiplexing symbol.

[0125] According to an embodiment of the present invention, the phase change rate may be calculated using the phases of three sampling points, or may be calculated using the phases of all sampling points in an orthogonal frequency division multiplexing symbol.

[0126] According to an embodiment of the present invention, the phase change rate can be expressed as formula (11).

[0127] (11)

[0128] Among them, STO m It can be represented as the phase change rate of the mth OFDM symbol.

[0129] According to an embodiment of the present invention, the above operation is performed on each OFDM symbol in a plurality of OFDM symbols to obtain a phase change rate corresponding to each OFDM symbol.

[0130] According to an embodiment of the present invention, the above operation can also be performed only on each of the three orthogonal frequency division multiplexing symbols to obtain the phase change rate corresponding to each of the three orthogonal frequency division multiplexing symbols, so as to improve the processing efficiency of the system while ensuring error accuracy.

[0131] According to an embodiment of the present invention, for any one of a plurality of orthogonal frequency division multiplexing symbols, the subcarrier phase corresponding to each subcarrier is obtained from the frequency domain values of a plurality of subcarriers corresponding to any one of the orthogonal frequency division multiplexing symbols, the sampling point phase corresponding to each sampling point is determined according to the subcarrier phase corresponding to each subcarrier, and the phase change rate corresponding to any one of the orthogonal frequency division multiplexing symbols is obtained by calculation based on the plurality of sampling point phases. The above operation is performed on each of the plurality of orthogonal frequency division multiplexing symbols to obtain the phase change rate corresponding to each of the orthogonal frequency division multiplexing symbols, so as to analyze the phase change rate of the orthogonal frequency division multiplexing symbol and obtain the precise target sampling frequency deviation of the orthogonal frequency division multiplexing signal.

[0132] According to an embodiment of the present invention, a method for performing minimum mean square error estimation processing on phase change rates corresponding to at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to an orthogonal frequency division multiplexing signal includes the following operations.

[0133] According to an embodiment of the present invention, a phase change rate matrix corresponding to an OFDM signal is constructed based on the phase change rate corresponding to each OFDM symbol in at least three OFDM symbols.

[0134] According to an embodiment of the present invention, since the phase change rates of multiple orthogonal frequency division multiplexing symbols are linearly related, a change rate matrix can be constructed based on only the phase change rates of three orthogonal frequency division multiplexing symbols, thereby calculating the clock deviation change rate of the entire signal, that is, the orthogonal frequency division multiplexing signal.

[0135] According to an embodiment of the present invention, based on a predetermined relationship between the phase change rate and the sampling clock deviation, the phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal is processed according to the ordinal matrix and noise parameters of each orthogonal frequency division multiplexing symbol to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal.

[0136] According to an embodiment of the present invention, the predetermined relationship between the phase change rate and the sampling clock deviation can be characterized as the phase change rate being proportional to the sampling clock deviation of the entire OFDM signal.

[0137] According to an embodiment of the present invention, the phase change rate matrix corresponding to the OFDM signal may be processed according to the ordinal matrix and noise parameter of each OFDM symbol as expressed in formula (12).

[0138] (12)

[0139] in, It can be represented as a phase change rate matrix, It can be represented as an ordinal matrix, noise can be represented as a noise parameter, Slope STO It can be characterized as the rate of change of clock deviation.

[0140] According to an embodiment of the present invention, based on formula (12), the clock deviation change rate can be expressed as formula (13).

[0141] (13)

[0142] Among them, Slope STO It can be characterized as the rate of change of clock deviation.

[0143] According to an embodiment of the present invention, a phase change rate matrix corresponding to an orthogonal frequency division multiplexing signal is constructed according to the phase change rate corresponding to each orthogonal frequency division multiplexing symbol. Based on a predetermined relationship between the phase change rate and the sampling clock deviation, the phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal is processed according to the ordinal matrix and noise parameters of each orthogonal frequency division multiplexing symbol to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal. This realizes analysis of the phase change rate and obtains the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal, so as to obtain an accurate target sampling frequency deviation according to the obtained clock deviation change rate.

[0144] According to an embodiment of the present invention, a method for calculating a target sampling frequency deviation based on a clock deviation change rate corresponding to an orthogonal frequency division multiplexing signal includes the following operations.

[0145] According to an embodiment of the present invention, the sampling clock deviation corresponding to the OFDM signal is obtained according to the clock deviation change rate corresponding to the OFDM signal.

[0146] According to an embodiment of the present invention, the sampling clock deviation can be expressed as formula (14).

[0147] (14)

[0148] Among them, △T s It can be characterized as sampling clock deviation.

[0149] According to an embodiment of the present invention, based on a predetermined relationship between the sampling clock deviation and the sampling frequency deviation, a target sampling frequency deviation is calculated according to the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal.

[0150] According to an embodiment of the present invention, the predetermined relationship between the sampling clock deviation and the sampling frequency deviation may be expressed as formula (15).

[0151] (15)

[0152] Among them, SFO can be characterized as sampling frequency deviation.

[0153] According to an embodiment of the present invention, the sampling frequency deviation calculated using formula (15) is the target sampling frequency deviation.

[0154] According to an embodiment of the present invention, a sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal is obtained based on the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal. Based on a predetermined relationship between the sampling clock deviation and the sampling frequency deviation, a target sampling frequency deviation is calculated according to the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal. This allows the target sampling frequency deviation corresponding to the orthogonal frequency division multiplexing signal for sampling processing to be accurately obtained using only the phase change rate between three orthogonal frequency division multiplexing symbols. In the process of obtaining the target sampling frequency deviation, there is no need to determine the target sampling frequency deviation based on reference symbols such as pilot symbols and training symbols. This improves the signal utilization and spectrum utilization of the orthogonal frequency division multiplexing signal, and makes the orthogonal frequency division multiplexing signal have lower complexity, so as to improve the processing efficiency of the receiving end, reduce processing energy consumption, and improve the reliability of signal processing.

[0155] According to an embodiment of the present invention, the non-data-assisted method for estimating sampling frequency deviation further includes the following operations.

[0156] According to an embodiment of the present invention, a transmission sampling frequency for transmitting an orthogonal frequency division multiplexing signal is acquired.

[0157] According to an embodiment of the present invention, the target sampling frequency is calculated based on the sampling frequency deviation and the transmission sampling frequency.

[0158] According to an embodiment of the present invention, the target sampling frequency can be expressed as formula (16).

[0159] (16)

[0160] Among them, f s It can be characterized as the transmit sampling frequency used to transmit the OFDM signal, f s ' can be characterized as the target sampling frequency.

[0161] According to an embodiment of the present invention, an orthogonal frequency division multiplexing signal is resampled using a target sampling frequency to obtain a target orthogonal frequency division multiplexing signal.

[0162] According to an embodiment of the present invention, after resampling the signal, the resampled signal may be demodulated to obtain specific information in the signal.

[0163] According to an embodiment of the present invention, by obtaining the transmission sampling frequency used to transmit the orthogonal frequency division multiplexing signal, the target sampling frequency is calculated based on the sampling frequency deviation and the transmission sampling frequency, and the orthogonal frequency division multiplexing signal is resampled using the target sampling frequency to obtain the target orthogonal frequency division multiplexing signal, the resampling and demodulation of the received signal are realized to obtain an accurate signal, thereby performing subsequent processing based on the signal.

[0164] Figure 3 FIG. 4 is a schematic diagram showing a sampling frequency deviation according to an embodiment of the present invention.

[0165] like Figure 3 As shown, Figure 3 The figure shows the sampling frequency deviation between the transmitting end and the receiving end. The orthogonal frequency division multiplexing signal transmitted by the transmitting end to the receiving end includes 12 sampling points. However, due to the sampling frequency deviation between the transmitting end and the receiving end, the number of sampling points included in the orthogonal frequency division multiplexing signal after sampling according to the actual frequency at the receiving end is not 12. As shown in the figure, when the sampling clock deviation of the receiving end is greater than 0, the number of sampling points included in the received orthogonal frequency division multiplexing signal is 11. When the sampling clock deviation of the receiving end is less than 0, the number of sampling points included in the received orthogonal frequency division multiplexing signal is 13.

[0166] Figure 4a A schematic diagram of a constellation after demodulation of the second orthogonal frequency division multiplexing symbol according to an embodiment of the present invention is shown. Figure 4b A schematic diagram of a constellation after demodulation of the 12th orthogonal frequency division multiplexing symbol according to an embodiment of the present invention is shown. Figure 4c A schematic diagram of a constellation after demodulation of the 42nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention is shown. Figure 4d A schematic diagram of a constellation after demodulation of the 82nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention is shown.

[0167] like Figure 4a to Figure 4d As shown, Figure 4a to Figure 4d The constellation diagram after OFDM symbol demodulation is shown. The horizontal axis can be represented as the real part and the vertical axis can be represented as the imaginary part. Assuming that the sampling clock deviation is In the case of Quadrature Phase Shift Keying (QPSK) modulation, as the number of OFDM symbols increases, the constellation points after demodulation will be severely rotated and diffused and appear circular.

[0168] Figure 5a A schematic diagram shows the phase change of the second orthogonal frequency division multiplexing symbol according to an embodiment of the present invention. Figure 5bA schematic diagram shows a phase change of the 12th orthogonal frequency division multiplexing symbol according to an embodiment of the present invention. Figure 5c A schematic diagram shows a phase change of a 42nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention. Figure 5d A schematic diagram shows the phase change of the 82nd orthogonal frequency division multiplexing symbol according to an embodiment of the present invention.

[0169] like Figure 5a to Figure 5d As shown, Figure 5a to Figure 5d The phase change of the OFDM symbol is shown in FIG. , where the horizontal axis can be represented by the number of sampling points and the vertical axis can be represented by the phase of the sampling point. Figure 5a to Figure 5d As shown, for OFDM symbols, each sampling point corresponds to a sampling point phase. Figure 5a to Figure 5d There are multiple lines with consistent slopes in the OFDM symbol, so that the phase change rate of the entire OFDM symbol can be calculated based on some sampling points in the OFDM symbol.

[0170] Figure 6 A schematic diagram showing phase change rates of multiple orthogonal frequency division multiplexing symbols according to an embodiment of the present invention is shown.

[0171] like Figure 6 As shown, Figure 6 The phase change rate of multiple OFDM symbols is shown. The horizontal axis can be represented as the OFDM symbols in the OFDM signal, and the vertical axis can be represented as the phase change rate. It can be seen from the figure that the phase change rates between multiple OFDM symbols are linearly related, so the target sampling frequency deviation of the OFDM signal can be calculated based on only three OFDM symbols.

[0172] Figure 7a FIG. 1 is a schematic diagram showing a signal phase without compensating for sampling frequency deviation according to an embodiment of the present invention. Figure 7b A schematic diagram showing a signal phase in which a sampling frequency deviation is compensated by a method according to an embodiment of the present invention is shown.

[0173] like Figure 7a~Figure 7b As shown, Figure 7a~Figure 7b The signal phase without compensating the sampling frequency deviation and the signal phase after compensating the sampling frequency deviation by the method of the present invention are shown. Figure 7a It can be seen that the phases of the sampling points before compensation are not clear, but after compensation by the method of the present invention, the phases can present multiple clear phase lines.

[0174] Figure 8a A schematic diagram of a constellation after demodulation of the second orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown. Figure 8bA schematic diagram of a constellation after demodulation of the 12th orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown. Figure 8c A schematic diagram of a constellation after demodulation of the 42nd orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown. Figure 8d A schematic diagram of a constellation after demodulation of the 82nd orthogonal frequency division multiplexing symbol after compensation for the target sampling frequency deviation according to an embodiment of the present invention is shown.

[0175] like Figure 8a to Figure 8d As shown, Figure 8a to Figure 8d The figure shows a constellation diagram of the first OFDM signal after demodulation after compensation for the target sampling frequency deviation using the method of the present invention. The horizontal axis can be represented as the real part, and the vertical axis can be represented as the imaginary part. As can be seen from the figure, as the number of OFDM symbols increases, the demodulated constellation points will not experience severe rotation and diffusion. Through precise compensation for the target sampling frequency deviation, the demodulated constellation diagram is evenly distributed in four areas.

[0176] Figure 9 A structural block diagram of a non-data-assisted device for estimating sampling frequency deviation according to an embodiment of the present invention is shown.

[0177] like Figure 9 As shown, the non-data-assisted sampling frequency deviation estimation device of this embodiment includes: an extraction module 910, a frequency domain value obtaining module 920, a phase change rate obtaining module 930, a clock deviation obtaining module 940 and a frequency deviation obtaining module 950.

[0178] Extraction module 910 is configured to, in response to receiving an OFDM signal, extract at least three OFDM symbols from the OFDM signal, where the OFDM symbols include a plurality of data symbols and a cyclic prefix symbol. Extraction module 910 may be configured to perform operation S210 described above and will not be further described herein.

[0179] Frequency domain value obtaining module 920 is configured to perform discrete Fourier transform processing on the multiple subcarriers included in each OFDM symbol to obtain frequency domain values of the multiple subcarriers corresponding to each OFDM symbol. Frequency domain value obtaining module 920 can be used to perform operation S220 described above and will not be further described here.

[0180] The phase change rate obtaining module 930 is configured to obtain the phase change rate corresponding to each OFDM symbol based on the frequency domain values of the multiple subcarriers. The phase change rate obtaining module 930 can be used to perform the operation S230 described above, which will not be described in detail here.

[0181] Clock deviation obtaining module 940 is configured to perform minimum mean square error (MMSE) estimation on the phase change rates corresponding to at least three OFDM symbols to obtain a clock deviation change rate corresponding to the OFDM signal. Clock deviation obtaining module 940 can be configured to perform operation S240 described above and will not be further described herein.

[0182] The frequency deviation obtaining module 950 is used to calculate the target sampling frequency deviation according to the clock deviation change rate to adjust the sampling frequency of the OFDM signal. The frequency deviation obtaining module 950 can be used to perform the operation S250 described above, which will not be described in detail here.

[0183] According to an embodiment of the present invention, the extraction module 910 includes: a first acquisition submodule, a first determination submodule, and a first extraction submodule.

[0184] The first acquisition submodule is used to acquire the number of sampling points of the OFDM symbol, the number of sampling points of the cyclic prefix symbol, and the clock period used by the transmitter to transmit the OFDM signal.

[0185] The first determination submodule is used to determine a first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol based on the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol, and the clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal, wherein the first orthogonal time period indicates that all sampling points within the first orthogonal time period of the orthogonal frequency division multiplexing signal are sampling points included in any one orthogonal frequency division multiplexing symbol.

[0186] The first extraction submodule is configured to extract at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal based on a plurality of first orthogonal time periods.

[0187] According to an embodiment of the present invention, the frequency domain value obtaining module 920 includes: a second extraction submodule and a first obtaining submodule.

[0188] The second extraction submodule is configured to extract a plurality of sampling point signals corresponding to the sampling points from each orthogonal frequency division multiplexing symbol according to a first predetermined condition.

[0189] The first obtaining submodule is used to perform discrete Fourier transform processing on multiple sampling point signals respectively to obtain frequency domain values of multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol.

[0190] According to an embodiment of the present invention, the first predetermined condition is constructed based on a clock period and a sequence number of sampling points used by the transmitting end to transmit an orthogonal frequency division multiplexing signal.

[0191] According to an embodiment of the present invention, the phase change rate obtaining module 930 includes: a second obtaining submodule, a second determining submodule, a second obtaining submodule and a first executing submodule.

[0192] The second acquisition submodule is configured to acquire, for any one of the multiple OFDM symbols, a subcarrier phase corresponding to each subcarrier from frequency domain values of multiple subcarriers corresponding to the any one OFDM symbol.

[0193] The second determining submodule is configured to determine a sampling point phase corresponding to each sampling point according to a subcarrier phase corresponding to each subcarrier.

[0194] The second obtaining submodule is used to calculate according to the phases of multiple sampling points to obtain the phase change rate corresponding to any orthogonal frequency division multiplexing symbol.

[0195] The first execution submodule is configured to perform the above operation on each of a plurality of orthogonal frequency division multiplexing symbols to obtain a phase change rate corresponding to each orthogonal frequency division multiplexing symbol.

[0196] According to an embodiment of the present invention, the clock deviation obtaining module 940 further includes: a first constructing submodule and a first processing submodule.

[0197] The first construction submodule is configured to construct a phase change rate matrix corresponding to an orthogonal frequency division multiplexing signal according to a phase change rate corresponding to each orthogonal frequency division multiplexing symbol in at least three orthogonal frequency division multiplexing symbols.

[0198] The first processing submodule is used to process the phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal based on a predetermined relationship between the phase change rate and the sampling clock deviation and according to the ordinal matrix and noise parameter of each orthogonal frequency division multiplexing symbol to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal.

[0199] According to an embodiment of the present invention, the frequency deviation obtaining module 950 further includes: a first clock deviation submodule and a first frequency deviation submodule.

[0200] The first clock deviation submodule is configured to obtain a sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal according to a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal.

[0201] The first frequency deviation submodule is configured to calculate a target sampling frequency deviation based on a predetermined relationship between the sampling clock deviation and the sampling frequency deviation and according to the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal.

[0202] According to an embodiment of the present invention, the non-data-assisted device for estimating sampling frequency deviation further includes: an acquisition module, a calculation module, and a resampling module.

[0203] The acquisition module is used to acquire a transmission sampling frequency for transmitting an orthogonal frequency division multiplexing signal.

[0204] The calculation module is used to calculate the target sampling frequency according to the sampling frequency deviation and the transmission sampling frequency.

[0205] The resampling module is used to resample the OFDM signal using the target sampling frequency to obtain the target OFDM signal.

[0206] According to an embodiment of the present invention, any multiple modules among the extraction module 910, the frequency domain value acquisition module 920, the phase change rate acquisition module 930, the clock deviation acquisition module 940, and the frequency deviation acquisition module 950 may be combined into a single module, or any one of these modules may be split into multiple modules. Alternatively, at least part of the functionality of one or more of these modules may be combined with at least part of the functionality of other modules and implemented in a single module. According to an embodiment of the present invention, at least one of the extraction module 910, the frequency domain value acquisition module 920, the phase change rate acquisition module 930, the clock deviation acquisition module 940, and the frequency deviation acquisition module 950 may be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or may be implemented in hardware or firmware through any other reasonable method of circuit integration or packaging, or implemented in any one of the three implementation methods, or a suitable combination of any of these. Alternatively, at least one of the extraction module 910, the frequency domain value module 920, the phase change rate module 930, the clock deviation module 940 and the frequency deviation module 950 can be at least partially implemented as a computer program module, which can perform the corresponding function when it is executed.

[0207] Figure 10 A block diagram of an electronic device showing a non-data-aided method for estimating sampling frequency deviation according to an embodiment of the present invention is shown.

[0208] like Figure 10As shown, the electronic device according to an embodiment of the present invention includes a processor 1001, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage unit 1008 into a random access memory (RAM) 1003. Processor 1001 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. Processor 1001 may also include onboard memory for caching purposes. Processor 1001 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0209] Random Access Memory (RAM) 1003 stores various programs and data required for the operation of the electronic device. Processor 1001, Read-Only Memory (ROM) 1002, and Random Access Memory (RAM) 1003 are interconnected via bus 1004. Processor 1001 executes the various operations of the method flow according to the embodiment of the present invention by executing the programs stored in Read-Only Memory (ROM) 1002 and / or Random Access Memory (RAM) 1003. It should be noted that the programs may also be stored in one or more memories other than Read-Only Memory (ROM) 1002 and Random Access Memory (RAM) 1003. Processor 1001 may also execute the various operations of the method flow according to the embodiment of the present invention by executing the programs stored in one or more memories.

[0210] According to an embodiment of the present invention, the electronic device may further include an input / output (I / O) interface 1005, which is also connected to the bus 1004. The electronic device may also include one or more of the following components connected to the I / O interface 1005: an input section 1006 including a keyboard, mouse, etc.; an output section 1007 including devices such as a cathode ray tube (CRT), liquid crystal display (LCD), and speakers; a storage section 1008 including a hard disk; and a communication section 1009 including a network interface card such as a LAN card or modem. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. Removable media 1011, such as a magnetic disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed in the drive 1010 as needed, so that computer programs read from the removable media can be installed in the storage section 1008 as needed.

[0211] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments, or may exist independently and not incorporated into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present invention.

[0212] According to an embodiment of the present invention, a computer-readable storage medium may be a non-volatile computer-readable storage medium, such as, but not limited to, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present invention, a computer-readable storage medium may include the read-only memory (ROM) 1002 and / or random access memory (RAM) 1003 described above, and / or one or more memories other than the read-only memory (ROM) 1002 and random access memory (RAM) 1003.

[0213] Embodiments of the present invention also include a computer program product comprising a computer program containing program code for executing the method shown in the flowchart. When the computer program product is executed in a computer system, the program code is configured to cause the computer system to implement the non-data-assisted method for estimating sampling frequency deviation provided by an embodiment of the present invention.

[0214] The computer program executes the above functions defined in the system / device of the embodiment of the present invention when executed by the processor 1001. According to the embodiment of the present invention, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0215] In one embodiment, the computer program may be stored on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may be transmitted and distributed in the form of a signal on a network medium, downloaded and installed via the communication portion 1009, and / or installed from the removable medium 1011. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0216] In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 1009 and / or installed from the removable medium 1011. When the computer program is executed by the processor 1001, the above-described functions defined in the system of the embodiment of the present invention are performed. According to the embodiment of the present invention, the systems, devices, means, modules, units, etc. described above can be implemented by computer program modules.

[0217] Those skilled in the art will appreciate that the features described in the various embodiments of the present invention may be combined and / or coupled in various ways, even if such combinations and / or couplings are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention may be combined and / or coupled in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or couplings fall within the scope of the present invention.

Claims

1. A non-data-assisted method for estimating sampling frequency deviation, characterized in that: include: In response to receiving an orthogonal frequency division multiplexing signal, extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal, wherein the orthogonal frequency division multiplexing symbols include a plurality of data symbols and a cyclic prefix symbol; Performing discrete Fourier transform processing on the multiple subcarriers included in each of the orthogonal frequency division multiplexing symbols to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; According to the frequency domain values of the multiple subcarriers, a phase change rate corresponding to each of the orthogonal frequency division multiplexing symbols is obtained, wherein the phase change rate is obtained according to the following operations: from the frequency domain values of the multiple subcarriers corresponding to the orthogonal frequency division multiplexing symbols, a subcarrier phase corresponding to each of the subcarriers is obtained, according to the subcarrier phase corresponding to each of the subcarriers, a sampling point phase corresponding to each sampling point is determined, and according to the multiple sampling point phases, a calculation is performed to obtain the phase change rate corresponding to the orthogonal frequency division multiplexing symbol, wherein the phase change rate is shown in formula (1); （1）； Among them, STO m Characterized as the phase change rate of the mth OFDM symbol, N sub Characterized by the number of sampling points of the data symbol, △T S It is represented by the sampling clock deviation, m is represented by the ordinal number of the selected OFDM symbol, and M is represented by the number of sampling points of the OFDM symbol; Performing minimum mean square error estimation processing on the phase change rates corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; According to the clock deviation change rate, a target sampling frequency deviation is calculated to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

2. The method according to claim 1, characterized in that The extracting at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal in response to receiving the orthogonal frequency division multiplexing signal comprises: Acquire the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol, and a clock period used by a transmitter to transmit the orthogonal frequency division multiplexing signal; Determining, based on the number of sampling points of the orthogonal frequency division multiplexing symbol, the number of sampling points of the cyclic prefix symbol, and a clock period used by the transmitter to transmit the orthogonal frequency division multiplexing signal, a first orthogonal time period corresponding to each orthogonal frequency division multiplexing symbol, wherein the first orthogonal time period indicates that all sampling points within the first orthogonal time period of the orthogonal frequency division multiplexing signal are sampling points included in any one of the orthogonal frequency division multiplexing symbols; The at least three orthogonal frequency division multiplexing symbols are extracted from the orthogonal frequency division multiplexing signal based on a plurality of the first orthogonal time periods.

3. The method according to claim 1, characterized in that The performing discrete Fourier transform processing on the multiple subcarriers included in each of the orthogonal frequency division multiplexing symbols to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol includes: extracting a plurality of sampling point signals corresponding to the sampling points from each of the orthogonal frequency division multiplexing symbols according to a first predetermined condition; Discrete Fourier transform processing is performed on the multiple sampling point signals respectively to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol.

4. The method according to claim 3, characterized in that The first predetermined condition is constructed based on a clock period used by a transmitting end to transmit the orthogonal frequency division multiplexing signal and the sequence number of the sampling point.

5. The method according to claim 1, wherein The performing minimum mean square error estimation processing on the phase change rates corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal includes: Constructing a phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal according to the phase change rate corresponding to each of the at least three orthogonal frequency division multiplexing symbols; Based on a predetermined relationship between the phase change rate and the sampling clock deviation, and according to the ordinal matrix and noise parameters of each orthogonal frequency division multiplexing symbol, the phase change rate matrix corresponding to the orthogonal frequency division multiplexing signal is processed to obtain the clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal.

6. The method according to claim 1, characterized in that The step of calculating a target sampling frequency deviation according to the clock deviation change rate includes: Obtaining a sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal according to the clock deviation change rate; Based on a predetermined relationship between the sampling clock deviation and the sampling frequency deviation, a target sampling frequency deviation is calculated according to the sampling clock deviation corresponding to the orthogonal frequency division multiplexing signal.

7. The method according to claim 6, characterized in that The method further comprises: Acquiring a transmission sampling frequency for transmitting the orthogonal frequency division multiplexing signal; Calculating a target sampling frequency based on the sampling frequency deviation and the transmission sampling frequency; The OFDM signal is resampled using the target sampling frequency to obtain a target OFDM signal.

8. A non-data-assisted device for estimating sampling frequency deviation, characterized in that: include: an extraction module, configured to extract at least three orthogonal frequency division multiplexing symbols from the orthogonal frequency division multiplexing signal in response to receiving the orthogonal frequency division multiplexing signal, wherein the orthogonal frequency division multiplexing symbol includes a plurality of data symbols and a cyclic prefix symbol; A frequency domain value obtaining module, configured to perform discrete Fourier transform processing on the multiple subcarriers included in each of the orthogonal frequency division multiplexing symbols to obtain frequency domain values of the multiple subcarriers corresponding to each orthogonal frequency division multiplexing symbol; A phase change rate obtaining module is used to obtain a phase change rate corresponding to each of the orthogonal frequency division multiplexing symbols according to the frequency domain values of the multiple subcarriers corresponding to the orthogonal frequency division multiplexing symbols, wherein the phase change rate is obtained according to the following operations: obtaining a subcarrier phase corresponding to each of the subcarriers from the frequency domain values of the multiple subcarriers corresponding to the orthogonal frequency division multiplexing symbols, determining a sampling point phase corresponding to each sampling point according to the subcarrier phase corresponding to each of the subcarriers, and calculating according to the multiple sampling point phases to obtain the phase change rate corresponding to the orthogonal frequency division multiplexing symbols, wherein the phase change rate is shown in formula (1); （1）； Among them, STO m Characterized as the phase change rate of the mth OFDM symbol, N sub Characterized by the number of sampling points of the data symbol, △T S It is represented by the sampling clock deviation, m is represented by the ordinal number of the selected OFDM symbol, and M is represented by the number of sampling points of the OFDM symbol; a clock deviation obtaining module, configured to perform minimum mean square error estimation processing on the phase change rates corresponding to the at least three orthogonal frequency division multiplexing symbols to obtain a clock deviation change rate corresponding to the orthogonal frequency division multiplexing signal; The frequency deviation obtaining module is used to calculate the target sampling frequency deviation according to the clock deviation change rate to adjust the sampling frequency of the orthogonal frequency division multiplexing signal.

9. An electronic device comprising: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors are enabled to execute the method according to any one of claims 1 to 7.

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