OFDM signal processing method and device, computer equipment and storage medium

Abstract

The invention relates to an OFDM (Orthogonal Frequency Division Multiplexing) signal processing method and device, computer equipment and a storage medium. The method comprises the following steps: respectively carrying out carrier demodulation processing on each OFDM signal; performing channel estimation processing on each demodulated sub-carrier signal corresponding to each antenna to obtain a channel estimation result, performing channel equalization processing on each demodulated sub-carrier signal according to the channel estimation result to obtain a first compensation sub-carrier signal, and performing channel equalization processing on each demodulated sub-carrier signal according to the difference between the local pilot frequency sub-carrier signal and the pilot frequency compensation sub-carrier signal to obtain a second compensation sub-carrier signal; performing compensation processing on each first compensation subcarrier signal to obtain a second compensation subcarrier signal; determining a target signal-to-noise ratio and a combination weight corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna; and merging the second compensation subcarrier signals according to the merging weights corresponding to the antennas, and performing data demodulation processing on the merged signals to obtain target data. By adopting the method, the precision of the restored target data can be improved.

Description

Technical Field

[0001] The present application relates to the field of communications, and in particular to an OFDM signal processing method, apparatus, computer equipment and storage medium. Background Art

[0002] The Orthogonal Frequency Division Multiplexing (OFDM) system is a system that uses a single antenna to send signals at the transmitting end and multiple antennas to receive signals at the receiving end. Since there are spatial differences between antennas, the signals received by each antenna are different. The performance of the OFDM system can be improved by filtering or combining the signals received by each antenna.

[0003] In the related art, the best signal is usually selected from the signals received by multiple antennas for output, or the signals received by multiple antennas are combined according to a certain algorithm. However, the first solution does not take advantage of the multi-antenna system, and the system demodulation performance is not improved compared with the single-antenna system. The second solution usually adopts the equal gain combining method in the related art, which is not as good as the maximum ratio combining method, and cannot handle the phenomenon of inconsistent phases of multiple antennas, resulting in poor system demodulation performance even though the signals received by different antennas are used at the same time. Summary of the invention

[0004] Based on this, it is necessary to provide an OFDM signal processing method, apparatus, computer equipment and storage medium to address the above technical issues.

[0005] In a first aspect, the present application provides an OFDM signal processing method. The method comprises:

[0006] Receiving OFDM signals through multiple antennas respectively, and performing carrier demodulation processing on each of the OFDM signals respectively, to obtain multiple demodulated subcarrier signals corresponding to each antenna;

[0007] For any one of the antennas, perform channel estimation processing on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result, perform channel equalization processing on each of the demodulated subcarrier signals according to the channel estimation result to obtain a first compensation subcarrier signal, and perform compensation processing on each of the first compensation subcarrier signals according to a difference between a local pilot subcarrier signal and a pilot compensation subcarrier signal in each of the first compensation subcarrier signals to obtain a second compensation subcarrier signal;

[0008] Determine a target signal-to-noise ratio corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna, and determine a combining weight corresponding to each antenna according to the target signal-to-noise ratio;

[0009] The second compensated subcarrier signals are combined according to the combining weights corresponding to the antennas to obtain a combined signal, and the combined signal is demodulated to obtain target data.

[0010] In one embodiment, the performing compensation processing on each of the first compensation subcarrier signals according to the difference between the local pilot subcarrier signal and the pilot compensation subcarrier signal in each of the first compensation subcarrier signals to obtain the second compensation subcarrier signal includes:

[0011] Determine each pilot compensation subcarrier signal from each of the first compensation subcarrier signals;

[0012] Performing conjugate multiplication processing on each of the pilot compensation subcarrier signals and the local pilot subcarrier signals corresponding to each of the pilot compensation subcarrier signals to obtain a target correlation value;

[0013] The compensation phase difference is determined according to each of the target correlation values, and the compensation processing is performed on each of the first compensation subcarrier signals according to the compensation phase difference to obtain a second compensation subcarrier signal.

[0014] In one embodiment, the performing carrier demodulation processing on each of the OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna includes:

[0015] For any of the OFDM signals, perform timing coarse synchronization processing on the OFDM signal to obtain a frame start position of the OFDM signal, and perform compensation processing on the OFDM signal according to the frame start position and a phase difference between a plurality of consecutive short sequences in the OFDM signal to obtain a coarse frequency offset compensated OFDM signal;

[0016] For any of the coarse frequency offset compensated OFDM signals, perform timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol starting position of the coarse frequency offset compensated OFDM signal, and perform compensation processing on the coarse frequency offset compensated OFDM signal according to the symbol starting position and a phase difference between a plurality of continuous long sequences in the OFDM signal to obtain a fine frequency offset compensated OFDM signal;

[0017] Carrier demodulation processing is performed on each of the precise frequency offset compensated OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna.

[0018] In one embodiment, performing timing coarse synchronization processing on the OFDM signal to obtain a frame start position of the OFDM signal includes:

[0019] Generating a delayed signal corresponding to the OFDM signal, and performing conjugation processing on the OFDM signal to obtain a first conjugated signal;

[0020] Multiplying the delayed signal and the first conjugate signal to obtain a first correlation value between the delayed signal and the first conjugate signal, and accumulating the first correlation value in a first sliding window to obtain a first cumulative sum;

[0021] Multiplying the OFDM signal and the first conjugated signal to obtain a second correlation value between the OFDM signal and the first conjugated signal, and accumulating the second correlation value within the first sliding window to obtain a second cumulative sum;

[0022] The frame start position of the OFDM signal is determined according to a difference between the second accumulated sum and the first accumulated sum, and / or a ratio between the second accumulated sum and the first accumulated sum.

[0023] In one embodiment, the performing timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol start position of the coarse frequency offset compensated OFDM signal includes:

[0024] Performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a second conjugate signal, and performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a third conjugate signal;

[0025] performing multiplication processing on the second conjugate signal and the coarse frequency offset compensated OFDM signal to obtain a third correlation value, and performing sliding correlation processing on the third conjugate signal and the coarse frequency offset compensated OFDM signal to obtain fourth correlation values ​​corresponding to different sliding values;

[0026] A symbol start position of the coarse frequency offset compensated OFDM signal is determined according to a difference between each of the fourth correlation values ​​and the third correlation value.

[0027] In one embodiment, performing channel estimation processing on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result includes:

[0028] Determining a pilot demodulated subcarrier signal from each of the demodulated subcarrier signals;

[0029] Performing conjugate multiplication processing on the pilot demodulation subcarrier signal and the local synchronization subcarrier signal to obtain a target pilot signal;

[0030] Performing inverse Fourier transform processing on the target pilot signal to obtain a time domain pilot signal, performing noise suppression processing on the time domain pilot signal, and performing Fourier transform on the time domain pilot signal after the noise suppression processing to obtain a denoised pilot signal;

[0031] A channel estimation result is obtained according to the target pilot signal and the denoised pilot signal.

[0032] In one of the embodiments, determining the combining weights corresponding to the antennas according to the target signal-to-noise ratio includes:

[0033] Summing the target signal-to-noise ratios corresponding to the antennas to obtain a target signal-to-noise ratio sum;

[0034] For any of the antennas, a combining weight corresponding to the antenna is determined according to a ratio of the target signal-to-noise ratio corresponding to the antenna to the sum of the target signal-to-noise ratios.

[0035] In a second aspect, the present application also provides an OFDM signal processing device. The device comprises:

[0036] A receiving module, used to receive OFDM signals through multiple antennas respectively, and perform carrier demodulation processing on each of the OFDM signals respectively to obtain multiple demodulated subcarrier signals corresponding to each antenna;

[0037] a compensation module, configured to perform channel estimation processing on each demodulated subcarrier signal corresponding to any antenna to obtain a channel estimation result, perform channel equalization processing on each demodulated subcarrier signal according to the channel estimation result to obtain a first compensated subcarrier signal, and perform compensation processing on each first compensated subcarrier signal according to a difference between a local pilot subcarrier signal and a pilot compensated subcarrier signal in each first compensated subcarrier signal to obtain a second compensated subcarrier signal;

[0038] A determination module, configured to determine a target signal-to-noise ratio corresponding to each of the antennas according to each second compensation subcarrier signal corresponding to each of the antennas, and determine a combining weight corresponding to each of the antennas according to the target signal-to-noise ratio;

[0039] The merging module is used to merge the second compensated subcarrier signals according to the merging weights corresponding to the antennas to obtain a merged signal, and perform data demodulation on the merged signal to obtain target data.

[0040] In one embodiment, the compensation module is further used for:

[0041] Determine each pilot compensation subcarrier signal from each of the first compensation subcarrier signals;

[0042] Performing conjugate multiplication processing on each of the pilot compensation subcarrier signals and the local pilot subcarrier signals corresponding to each of the pilot compensation subcarrier signals to obtain a target correlation value;

[0043] The compensation phase difference is determined according to each of the target correlation values, and the compensation processing is performed on each of the first compensation subcarrier signals according to the compensation phase difference to obtain a second compensation subcarrier signal.

[0044] In one embodiment, the receiving module is further used for:

[0045] For any of the OFDM signals, perform timing coarse synchronization processing on the OFDM signal to obtain a frame start position of the OFDM signal, and perform compensation processing on the OFDM signal according to the frame start position and a phase difference between a plurality of consecutive short sequences in the OFDM signal to obtain a coarse frequency offset compensated OFDM signal;

[0046] For any of the coarse frequency offset compensated OFDM signals, perform timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol starting position of the coarse frequency offset compensated OFDM signal, and perform compensation processing on the coarse frequency offset compensated OFDM signal according to the symbol starting position and a phase difference between a plurality of continuous long sequences in the OFDM signal to obtain a fine frequency offset compensated OFDM signal;

[0047] Carrier demodulation processing is performed on each of the precise frequency offset compensated OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna.

[0048] In one embodiment, the receiving module is further used for:

[0049] Generating a delayed signal corresponding to the OFDM signal, and performing conjugation processing on the OFDM signal to obtain a first conjugated signal;

[0050] Multiplying the delayed signal and the first conjugate signal to obtain a first correlation value between the delayed signal and the first conjugate signal, and accumulating the first correlation value in a first sliding window to obtain a first cumulative sum;

[0051] Multiplying the OFDM signal and the first conjugated signal to obtain a second correlation value between the OFDM signal and the first conjugated signal, and accumulating the second correlation value within the first sliding window to obtain a second cumulative sum;

[0052] The frame start position of the OFDM signal is determined according to a difference between the second accumulated sum and the first accumulated sum, and / or a ratio between the second accumulated sum and the first accumulated sum.

[0053] In one embodiment, the receiving module is further used for:

[0054] Performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a second conjugate signal, and performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a third conjugate signal;

[0055] performing multiplication processing on the second conjugate signal and the coarse frequency offset compensated OFDM signal to obtain a third correlation value, and performing sliding correlation processing on the third conjugate signal and the coarse frequency offset compensated OFDM signal to obtain fourth correlation values ​​corresponding to different sliding values;

[0056] A symbol start position of the coarse frequency offset compensated OFDM signal is determined according to a difference between each of the fourth correlation values ​​and the third correlation value.

[0057] In one embodiment, the compensation module is further used for:

[0058] Determining a pilot demodulated subcarrier signal from each of the demodulated subcarrier signals;

[0059] Performing conjugate multiplication processing on the pilot demodulation subcarrier signal and the local synchronization subcarrier signal to obtain a target pilot signal;

[0060] Performing inverse Fourier transform processing on the target pilot signal to obtain a time domain pilot signal, performing noise suppression processing on the time domain pilot signal, and performing Fourier transform on the time domain pilot signal after the noise suppression processing to obtain a denoised pilot signal;

[0061] A channel estimation result is obtained according to the target pilot signal and the denoised pilot signal.

[0062] In one embodiment, the determining module is further used to:

[0063] Summing the target signal-to-noise ratios corresponding to the antennas to obtain a target signal-to-noise ratio sum;

[0064] For any of the antennas, a combining weight corresponding to the antenna is determined according to a ratio of the target signal-to-noise ratio corresponding to the antenna to the sum of the target signal-to-noise ratios.

[0065] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, any one of the above methods is implemented.

[0066] In a fourth aspect, the present application further provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, any of the above methods is implemented.

[0067] In a fifth aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and when the computer program is executed by a processor, any of the above methods is implemented.

[0068] The above-mentioned OFDM signal processing method, device, computer equipment and storage medium, after performing channel estimation and channel equalization on the subcarrier signals of each antenna respectively, further compensate and align each subcarrier signal according to the pilot signal, and then calculate the signal-to-noise ratio, and determine the merging weight of each antenna according to the signal-to-noise ratio, merge the subcarrier signals of each antenna according to the merging weight, and then perform data demodulation on the merged signal to obtain the target data. In the embodiment of the present application, the signal-to-noise ratio is calculated after compensating and aligning the subcarrier signals, which can eliminate the influence of the channel on the signal to the greatest extent, improve the calculation accuracy of the signal-to-noise ratio, and then improve the accuracy of the weight calculated when merging the antenna signals, so that the signal obtained after merging is more accurate. At the same time, the embodiment of the present application merges the subcarrier signals after aligning the subcarrier signals, which can avoid the problem of inconsistent subcarrier phases of different antennas, which affects data demodulation after merging, and improve the accuracy of the restored target data. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 1 is a flow chart of an OFDM signal processing method according to an embodiment;

[0070] Figure 2 is a flow chart of step 104 in one embodiment;

[0071] Figure 3 is a flow chart of step 102 in one embodiment;

[0072] Figure 4 is a flow chart of step 302 in one embodiment;

[0073] Figure 5 A schematic diagram of a flow chart of timing coarse synchronization and coarse frequency offset compensation in one embodiment;

[0074] Figure 6 is a flow chart of step 304 in one embodiment;

[0075] Figure 7 A schematic diagram of a flow chart of precise timing synchronization and precise frequency offset compensation in one embodiment;

[0076] Figure 8 is a flow chart of step 104 in one embodiment;

[0077] Fig. 9 A schematic diagram of a process of channel estimation and channel equalization in one embodiment;

[0078] Fig.10 1 is a flow chart of an OFDM signal processing method according to an embodiment;

[0079] Fig.11 is a schematic diagram of an OFDM symbol in one embodiment;

[0080] Fig.12 is a structural block diagram of an OFDM signal processing device in one embodiment;

[0081] Fig.13 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0083] In one embodiment, Figure 1 As shown, an OFDM signal processing method is provided. This embodiment uses the method applied to an OFDM signal receiver as an example, and includes the following steps:

[0084] Step 102: OFDM signals are received through multiple antennas respectively, and carrier demodulation processing is performed on each OFDM signal respectively to obtain multiple demodulated subcarrier signals corresponding to each antenna.

[0085] In the embodiment of the present application, the number of antennas of the OFDM signal receiver is greater than or equal to 2. The OFDM signal receiver can use multiple antennas to receive OFDM signals at the same time. For the OFDM signal received by each antenna, the OFDM signal receiver can use any demodulation method to perform carrier demodulation processing on the OFDM signal, and the embodiment of the present application does not specifically limit the demodulation method. After demodulation, each demodulated subcarrier signal contained in the OFDM signal can be restored.

[0086] Step 104: for any antenna, perform channel estimation processing on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result, perform channel equalization processing on each demodulated subcarrier signal according to the channel estimation result to obtain a first compensated subcarrier signal, and perform compensation processing on each first compensated subcarrier signal according to a difference between a local pilot subcarrier signal and a pilot compensated subcarrier signal in each first compensated subcarrier signal to obtain a second compensated subcarrier signal.

[0087] In the embodiment of the present application, after demodulating the OFDM signal, channel estimation, channel compensation and residual phase tracking are sequentially performed on each demodulated subcarrier signal received by each antenna to obtain a second compensated subcarrier signal.

[0088] Channel estimation refers to the influence of estimating the signal when it is transmitted in the channel. The channel estimation result may include information such as the impulse response and frequency response of the channel. Since OFDM signals generally carry pilot signals, and the OFDM signal receiver generally stores a local pilot signal corresponding to the pilot signal locally, the OFDM signal can be channel estimated based on the difference between the pilot signal and the local pilot signal. The embodiment of the present application does not limit the specific method of channel estimation, and can use the least squares (LS), minimum mean square error (MMSE) and other methods to perform channel estimation based on the pilot signal and the local pilot signal.

[0089] After obtaining the channel estimation result, the channel estimation result can be used to perform channel compensation processing on each demodulated subcarrier signal to eliminate the channel influence on the demodulated subcarrier signal. The signal affected by the channel can generally be modeled as Y=XH+Z, where Y is the received signal, X is the transmitted signal, H is the influence caused by the channel, and Z is the noise. Therefore, after obtaining H in the model through the channel estimation result, the received signal with the channel influence eliminated can be calculated according to the model, that is, the first compensated subcarrier signal.

[0090] Since the channel estimation result is only an estimated value, there may be residual channel effects in the signal after channel compensation. In addition, the signal may have frequency deviation during transmission and sampling deviation during sampling. The above factors will affect the accuracy of the first compensated subcarrier signal. Therefore, it is necessary to further compensate the first compensated subcarrier signal to improve the accuracy of each second compensated subcarrier signal obtained after compensation, and eliminate the phase difference of the first compensated subcarrier signal corresponding to different antennas, so as to facilitate the subsequent merging of the subcarrier signals received by each antenna.

[0091] In OFDM signals, pilot signals are generally transmitted on one or more subcarriers. After carrier demodulation and channel equalization, the pilot signals will be converted into pilot compensation subcarrier signals. The local pilot subcarrier signal corresponding to the subcarrier where the pilot signal is located can be obtained from the local pilot signal, and then the phase difference between the local pilot subcarrier signal and the pilot compensation subcarrier signal can be obtained to obtain the phase compensation value. After compensating each first compensation subcarrier signal according to the phase compensation value, each second compensation subcarrier signal can be obtained.

[0092] In one embodiment, Figure 2 As shown, the specific steps for obtaining the phase compensation value are:

[0093] Step 202, determining each pilot compensation subcarrier signal from each first compensation subcarrier signal;

[0094] Step 204, performing conjugate multiplication processing on each pilot compensation subcarrier signal and the local pilot subcarrier signal corresponding to each pilot compensation subcarrier signal to obtain a target correlation value;

[0095] Step 206: determine the compensation phase difference according to each target correlation value, and perform compensation processing on each first compensation subcarrier signal according to the compensation phase difference to obtain a second compensation subcarrier signal.

[0096] In the embodiment of the present application, since both the pilot compensation subcarrier signal and the local pilot subcarrier signal can be expressed as complex numbers, and the pilot compensation subcarrier signal and the corresponding local pilot subcarrier signal have the same amplitude and period, each pilot compensation subcarrier signal and the corresponding local pilot subcarrier signal are conjugate multiplied to obtain a target correlation value that can characterize the phase difference between the two signals. The principle is to assume that a pilot compensation subcarrier signal can be written as , and its corresponding local pilot subcarrier signal can be written as , then the result of conjugate multiplication of these two symbols is , That is, the phase difference between the two signals.

[0097] According to the target correlation value between each pilot compensation subcarrier signal and the local pilot subcarrier signal, the compensation phase difference to be compensated can be further calculated. For example, the compensation phase difference can be obtained by summing up each target correlation value and taking the inverse tangent value, or the compensation phase difference can be obtained by summing up the remaining phase differences and taking the inverse tangent value after eliminating the target correlation values ​​that are obviously too large or too small. See formula (I):

[0098] Formula (I)

[0099] in, is the kth pilot compensation subcarrier signal, is the conjugate of the kth local pilot subcarrier signal, Im represents the imaginary part of the product, and Re represents the real part of the product. N is the total number of pilot compensation subcarrier signals. Calculate the inverse tangent and divide by , the compensated phase difference expressed in radians can be obtained.

[0100] By performing compensation processing on each first compensation subcarrier signal according to the phase difference, each first compensation subcarrier signal with the phase difference eliminated can be obtained.

[0101] Step 106: determine a target signal-to-noise ratio corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna, and determine a combining weight corresponding to each antenna according to the target signal-to-noise ratio.

[0102] In the embodiment of the present application, the target signal-to-noise ratio is used to characterize the signal reception quality of the antenna, and the target signal-to-noise ratio can be obtained by calculating the signal-to-noise ratio of each second compensated subcarrier signal, and then calculating each solved signal-to-noise ratio. Since each second compensated subcarrier signal has been compensated twice by channel compensation and phase compensation, most of the non-noise influencing factors have been eliminated, so it is more accurate to calculate the signal-to-noise ratio at this time.

[0103] The specific method for calculating the signal-to-noise ratio is not limited in the embodiment of the present application, and the signal-to-noise ratio of each second compensation subcarrier signal can be obtained by any existing method. After that, the target signal-to-noise ratio can be obtained by averaging each signal-to-noise ratio, taking the maximum value of each signal-to-noise ratio, etc.

[0104] Since the larger the target signal-to-noise ratio, the better the signal reception quality of the antenna, the combined weight of each antenna can be made positively correlated with the target signal-to-noise ratio. For example, the largest target signal-to-noise ratio among the target signal-to-noise ratios can be determined, and for any antenna, the ratio of the target signal-to-noise ratio of the antenna to the largest target signal-to-noise ratio is used as the combined weight of the antenna. Alternatively, the target signal-to-noise ratios corresponding to each antenna can be summed to obtain the target signal-to-noise ratio sum, and for any antenna, the combined weight corresponding to the antenna can be determined based on the ratio of the target signal-to-noise ratio corresponding to the antenna to the target signal-to-noise ratio sum.

[0105] Step 108: Combine the second compensated subcarrier signals according to the combining weights corresponding to the antennas to obtain a combined signal, and demodulate the combined signal to obtain target data.

[0106] In the embodiment of the present application, the second compensation subcarrier signals corresponding to each antenna are weighted and combined symbol by symbol according to the combining weights of each antenna to obtain a combined signal. After obtaining the combined signal, the combined signal can be further subjected to data demodulation processing to obtain a bit stream carried in the signal. The bit stream can also be further processed, such as descrambling, deinterleaving, decoding, and cyclic redundancy checking to obtain the target data carried in the OFDM signal.

[0107] The OFDM signal processing method provided in the embodiment of the present application performs channel estimation and channel equalization on the subcarrier signals of each antenna respectively, and then further compensates and aligns each subcarrier signal according to the pilot signal, and then calculates the signal-to-noise ratio, and determines the merging weight of each antenna according to the signal-to-noise ratio, and after merging the subcarrier signals of each antenna according to the merging weight, the merged signal is demodulated to obtain the target data. The embodiment of the present application calculates the signal-to-noise ratio after compensating and aligning the subcarrier signals, which can eliminate the influence of the channel on the signal to the greatest extent, improve the calculation accuracy of the signal-to-noise ratio, and then improve the accuracy of the weight calculated when merging the antenna signals, so that the signal obtained after merging is more accurate. At the same time, the embodiment of the present application merges the subcarrier signals after aligning the subcarrier signals, which can avoid the problem of inconsistent subcarrier phases of different antennas, which affects data demodulation after merging, and improves the accuracy of the restored target data.

[0108] In one embodiment, Figure 3 As shown, in step 102, each OFDM signal is subjected to carrier demodulation processing to obtain multiple demodulated subcarrier signals corresponding to each antenna, including:

[0109] Step 302, for any OFDM signal, perform timing coarse synchronization processing on the OFDM signal to obtain the frame start position of the OFDM signal, and perform compensation processing on the OFDM signal according to the frame start position and the phase difference between multiple groups of continuous short sequences in the OFDM signal to obtain a coarse frequency offset compensated OFDM signal;

[0110] Step 304, for any coarse frequency offset compensated OFDM signal, perform timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain the symbol starting position of the coarse frequency offset compensated OFDM signal, and perform compensation processing on the coarse frequency offset compensated OFDM signal according to the symbol starting position and the phase difference between multiple consecutive long sequences in the OFDM signal to obtain a fine frequency offset compensated OFDM signal;

[0111] Step 306: Carrier demodulation is performed on each of the precise frequency offset compensated OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna.

[0112] In an embodiment of the present application, before performing carrier demodulation, the OFDM signal is first subjected to timing coarse synchronization, coarse frequency offset estimation, coarse frequency offset compensation, timing fine synchronization, fine frequency offset estimation, and frequency offset fine compensation in sequence according to a synchronization sequence composed of multiple consecutive short sequences and multiple consecutive long sequences in the OFDM signal, so as to locate the starting position of each symbol of the OFDM signal and reduce interference between subcarriers and between symbols in the OFDM signal.

[0113] Timing coarse synchronization is used to locate the frame start position in the OFDM signal. After locating the frame start position, multiple groups of continuous short sequences in the OFDM signal can be obtained, and the frequency offset can be calculated based on the phase difference between the short sequences, and the OFDM signal can be coarsely compensated for the frequency offset. The embodiment of the present application does not specifically limit the method of timing coarse synchronization and coarse frequency offset compensation, and any coarse compensation method is applicable to the embodiment of the present application.

[0114] Precise timing synchronization is used to locate the symbol starting position in the OFDM symbol. After locating the symbol starting position, multiple consecutive long sequences in the OFDM signal can be obtained, and the frequency offset can be calculated based on the phase difference between the long sequences, and the OFDM signal can be precisely compensated for the frequency offset. The embodiments of the present application also do not specifically limit the methods of precise timing synchronization and precise frequency offset compensation, and any precise compensation method is applicable to the embodiments of the present application.

[0115] In one embodiment, Figure 4 As shown, the specific method of coarse synchronization includes:

[0116] Step 402, generating a delayed signal corresponding to the OFDM signal, and performing conjugate processing on the OFDM signal to obtain a first conjugate signal;

[0117] Step 404, multiplying the delayed signal and the first conjugate signal to obtain a first correlation value between the delayed signal and the first conjugate signal, and accumulating the first correlation value in a first sliding window to obtain a first cumulative sum;

[0118] Step 406, multiplying the OFDM signal and the first conjugate signal to obtain a second correlation value between the OFDM signal and the first conjugate signal, and accumulating the second correlation value within the first sliding window to obtain a second cumulative sum;

[0119] Step 408: Determine the frame start position of the OFDM signal according to the difference between the second accumulated sum and the first accumulated sum, and / or the ratio of the second accumulated sum to the first accumulated sum.

[0120] In the embodiment of the present application, a training sequence (a general term for short sequences and long sequences) is inserted at the beginning of an OFDM signal frame, and the principle that the training sequence is usually repeated multiple times is utilized. A first correlation value for reference is obtained by performing an autocorrelation operation on the OFDM signal, a second correlation value is obtained by performing a delayed autocorrelation operation on the OFDM signal, and the frame starting position of the OFDM signal is determined by calculating the difference or ratio between the first correlation value and the second correlation value in a sliding window.

[0121] Specifically, after receiving the OFDM signal, the OFDM signal is conjugated to obtain a first conjugated signal, and the OFDM signal is delayed to obtain a delayed signal. The specific delay length can be set by those skilled in the art based on experience, as long as it is less than the total length of the training sequence, and the embodiment of the present application does not make specific limitations.

[0122] Further, the OFDM signal and the first conjugate signal are multiplied to obtain an autocorrelation value (i.e., a first correlation value) of the OFDM signal, and the delayed signal and the first conjugate signal are multiplied to obtain a second correlation value. The first correlation value and the second correlation value are accumulated in the first sliding window, respectively, to obtain a first cumulative sum and a second cumulative sum in the first sliding window. The embodiment of the present application does not specifically limit the length of the sliding window, which can be set by those skilled in the art.

[0123] Since when the first sliding window reaches the training sequence at the beginning of the data frame, the first correlation value is equivalent to the correlation value of the training sequence itself, and the second correlation value is also equivalent to the correlation value of the training sequence itself, the difference between the first cumulative sum and the second cumulative sum should be small. Therefore, it is possible to determine whether the first sliding window reaches the beginning of the data frame by the difference between the first correlation value and the second correlation value, or the ratio between the first correlation value and the second correlation value. For example, a difference threshold and a ratio threshold can be pre-set, and when the difference between the second cumulative sum and the first cumulative sum is less than the difference threshold, or the ratio between the second cumulative sum and the first cumulative sum is less than the ratio threshold, or the difference between the second cumulative sum and the first cumulative sum is less than the difference threshold, and the ratio is also less than the ratio threshold, it is determined that the first sliding window reaches the training sequence at the beginning of the data frame, that is, at this time, the first sliding window is at the frame start position of the OFDM signal.

[0124] For a detailed diagram of timing coarse synchronization, please refer to Figure 5 shown. Figure 5After receiving the received signal, the received signal is divided into three paths, and each received signal is not processed, conjugated (obtaining the first conjugated signal) and delayed by a length of D (obtaining the delayed signal), and then the first conjugated signal and the received signal (that is, the OFDM signal mentioned above) are multiplied to obtain the first cumulative value, and the first conjugated signal and the delayed signal are multiplied to obtain the second cumulative value. The first cumulative value and the second cumulative value are respectively accumulated in a sliding window of a length of 3 times the delay length to obtain the first cumulative sum and the second cumulative sum, and then the first cumulative sum and the second cumulative sum can be firstly normalized to avoid the situation where the values ​​of the first cumulative sum and the second cumulative sum are too large or too small, which affects whether the difference or ratio between the first cumulative sum and the second cumulative sum is less than the difference threshold or the ratio threshold. Then, based on the principle described above, the frame start position of the OFDM signal is captured and determined. After the frame start position of the OFDM signal is obtained, the frequency offset of the OFDM signal can be further calculated according to the frame start position of the local synchronization sequence, and then coarse frequency offset compensation can be performed.

[0125] In one embodiment, Figure 6 As shown, the specific method of fine synchronization includes:

[0126] Step 602, performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a second conjugate signal, and performing conjugate processing on the local synchronization sequence to obtain a third conjugate signal;

[0127] Step 604, multiplying the second conjugate signal and the coarse frequency offset compensated OFDM signal to obtain a third correlation value, and performing sliding correlation processing on the third conjugate signal and the coarse frequency offset compensated OFDM signal to obtain fourth correlation values ​​corresponding to different sliding values;

[0128] Step 606: Determine the symbol start position of the coarse frequency offset compensated OFDM signal according to the difference between each fourth correlation value and the third correlation value.

[0129] In the embodiment of the present application, the OFDM signal is precisely synchronized by using the principle that the conjugate multiplication result of the OFDM signal and the local synchronization sequence is maximized when the OFDM signal is aligned with the local synchronization sequence.

[0130] Specifically, after receiving the coarse frequency offset compensated OFDM signal after coarse synchronization and coarse compensation, the coarse frequency offset compensated OFDM signal is conjugated to obtain a second conjugated signal, and the local synchronization sequence is conjugated to obtain a third conjugated signal. The second conjugated signal and the coarse frequency offset compensated OFDM signal are multiplied to obtain the autocorrelation value of the coarse frequency offset compensated OFDM signal, that is, the third correlation value. Then the third conjugated signal and the coarse frequency offset compensated OFDM signal are subjected to sliding correlation processing. That is, after delaying the coarse frequency offset compensated OFDM signal according to different sliding values, the coarse frequency offset compensated OFDM signal and the second conjugated signal are multiplied. If at a certain sliding value, the coarse frequency offset compensated OFDM signal and the second conjugated signal are completely aligned on each symbol, then the fourth correlation value corresponding to the sliding value should be the largest fourth correlation value among the fourth correlation values.

[0131] After each sliding correlation process, the difference between the third correlation value and the fourth correlation value obtained this time can be calculated. A difference threshold can be set in advance. If the difference between the third correlation value and the fourth correlation value is less than the difference threshold, it indicates that the coarse frequency offset compensated OFDM signal and the second conjugate signal are completely aligned on each symbol at this time, and the starting position of each symbol in the coarse frequency offset compensated OFDM signal can be determined according to the sliding value at this time. Alternatively, after a certain number of sliding correlation processes have been performed, the difference between the third correlation value and each fourth correlation value can be compared, and the sliding value corresponding to the fourth correlation value with the smallest difference can be selected to determine the starting position of each symbol in the coarse frequency offset compensated OFDM signal. The embodiments of the present application do not specifically limit this.

[0132] For more detailed diagrams of timing precision synchronization, please refer to Figure 7 shown. Figure 7 After receiving the received signal (coarse frequency offset compensated OFDM signal), the received signal is processed in two ways, and one of the received signals is conjugated to obtain the second conjugated signal, and the local synchronization sequence is conjugated to obtain the third conjugated signal. Then, according to the method described above, after obtaining the third correlation value (reference power) and the fourth correlation value (correlation power), the third correlation value and the fourth correlation value can also be firstly power normalized to avoid the situation where the values ​​of the third correlation value and the fourth correlation value are too large or too small, which affects whether the difference between the third correlation value and the fourth correlation value can be less than the difference threshold. Then, based on the principle described above, the symbol start position of the OFDM signal is captured and determined. After obtaining the symbol start position of the OFDM signal, the OFDM signal can be finely compensated for the frequency offset according to the symbol start position of the local synchronization sequence.

[0133] In one embodiment, Figure 8As shown, in step 104, channel estimation processing is performed on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result, including:

[0134] Step 802, determining a pilot demodulation subcarrier signal from each demodulation subcarrier signal;

[0135] Step 804, performing conjugate multiplication processing on the pilot demodulation subcarrier signal and the local synchronization subcarrier signal to obtain a target pilot signal;

[0136] Step 806, performing inverse Fourier transform processing on the target pilot signal to obtain a time domain pilot signal, performing noise suppression processing on the time domain pilot signal, and performing Fourier transform on the noise suppressed time domain pilot signal to obtain a denoised pilot signal;

[0137] Step 808: Obtain a channel estimation result according to the difference between the target pilot signal and the denoised pilot signal.

[0138] In an embodiment of the present application, when performing channel estimation, the pilot demodulation subcarrier signal obtained after demodulation can be conjugate multiplied with the local synchronization subcarrier signal corresponding to it in the local synchronization sequence to eliminate the data modulation influence of the pilot demodulation subcarrier signal, and then the target pilot signal obtained after eliminating the data modulation influence can be converted to the time domain by inverse Fourier transform. Then, the time domain pilot signal converted to the time domain can be subjected to time domain noise suppression processing by any filter to obtain the time domain pilot signal after noise removal. The signal after noise removal is then converted to the frequency domain by Fourier transform to obtain the denoised pilot signal.

[0139] According to the difference between the denoised pilot signal and the target pilot signal, the noise estimation value in the signal propagation process can be obtained. Therefore, in the modeling Y=XH+Z of the signal affected by the channel mentioned in the above embodiment, Y (received signal, where the pilot demodulation subcarrier signal can be used), X (transmitted signal, where the local synchronization subcarrier signal can be used), and Z (noise estimation value) are all known. Then, the channel estimation result H can be inferred based on the above three known values.

[0140] The overall process of channel estimation and channel equalization can be further seen in Fig. 9 . Fig. 9 IDFT refers to inverse discrete Fourier transform, and DFT refers to Fourier transform. The channel equalization algorithm uses the MMSE algorithm, that is, after obtaining the preliminary channel estimation result H in the previous channel estimation, H is multiplied by an adjustable weight coefficient W to obtain the channel estimation result H', and W is optimized so that the mean square error between the signal Y' compensated by H' and the actual received signal Y is minimized, and the final channel estimation result H' is obtained.

[0141] In one embodiment, Fig.10 FIG. 1 is a flowchart of an OFDM signal processing method. The method includes:

[0142] S1, receiving OFDM signals through multiple antennas respectively, and sequentially performing timing coarse synchronization, coarse frequency offset estimation and compensation processing, timing fine synchronization, and fine frequency offset estimation and compensation processing on each OFDM signal respectively.

[0143] Among them, coarse synchronization is used to achieve frame synchronization, and fine synchronization is used to achieve symbol synchronization. Coarse frequency offset estimation is used to eliminate integer multiple frequency offsets, and fine frequency offset estimation is used to eliminate decimal multiple frequency offsets.

[0144] S2, perform carrier demodulation processing on the OFDM signal after fine frequency offset compensation. Carrier demodulation processing includes removing the OFDM symbol prefix, Fourier transform and spectrum shift. OFDM symbol consists of a cyclic prefix (also known as a training sequence) and actual data. The length of a symbol is the sum of the length of the cyclic prefix and the length of the actual data. For details, see Fig.11 shown.

[0145] S3, performing channel estimation and channel equalization processing on each demodulated subcarrier signal obtained after carrier demodulation.

[0146] S4, performing residual phase tracking processing on each first compensation subcarrier signal obtained after channel equalization to obtain a second compensation subcarrier signal.

[0147] S5, respectively calculating the signal-to-noise ratio of each antenna according to the second compensation subcarrier signal. Compared with the signal-to-noise ratio calculated in the channel estimation module, the system signal-to-noise ratio calculated by this algorithm is more accurate.

[0148] S6, select the data signal from each second compensation subcarrier signal, and perform weighted combination according to the signal-to-noise ratio of each antenna. Here, the maximum ratio combining algorithm is used for weighted combination. Taking two antennas as an example, the specific weight calculation method can be seen in formula (II):

[0149] Formula (II)

[0150] in, is the symbol in the combined signal obtained after weighted combining, is the symbol in the second compensation subcarrier signal of antenna 1, is the weight of antenna 1, is the symbol in the second compensated subcarrier signal of antenna 2, is the weight of antenna 2, is the signal-to-noise ratio of antenna 1, is the signal-to-noise ratio of antenna 2.

[0151] S7, sequentially perform data demodulation, descrambling, deinterleaving, decoding, and CRC check processing on the combined signal to obtain the target data.

[0152] The OFDM signal processing method provided in the embodiment of the present application processes each received signal independently before antenna merging, merges the multi-antenna signals after channel equalization, and enables the signal-to-noise ratio estimation to be realized after channel equalization, which can improve the calculation accuracy of the signal-to-noise ratio, and at the same time, phase aligns the signals received by different antennas to improve the accuracy of the merged signal. In the case where the signal-to-noise ratio, frequency deviation, phase deviation, channel impulse response and other parameters of the antenna received signals are quite different, since this method adopts the maximum ratio merging idea and can improve the calculation accuracy of the signal-to-noise ratio and perform phase alignment, it has obvious advantages. In a low signal-to-noise ratio, large frequency deviation, and Gaussian channel environment, the service channel performance of the embodiment of the present application can be improved by 3dB, and in a multipath channel environment, the low-order modulation (BPSK or QPSK) channel performance can be improved by 3dB, and the high-order modulation (64QAM) channel performance can be improved by 2dB.

[0153] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0154] Based on the same inventive concept, the embodiment of the present application also provides an OFDM signal processing device for implementing the OFDM signal processing method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more OFDM signal processing device embodiments provided below can refer to the limitations of the OFDM signal processing method above, and will not be repeated here.

[0155] In one embodiment, Fig.12 As shown, an OFDM signal processing device 1200 is provided, including: a receiving module 1202, a compensation module 1204, a determination module 1206, and a merging module 1208, wherein:

[0156] The receiving module 1202 is used to receive OFDM signals through multiple antennas respectively, and perform carrier demodulation processing on each of the OFDM signals respectively to obtain multiple demodulated subcarrier signals corresponding to each antenna;

[0157] The compensation module 1204 is configured to perform channel estimation processing on each demodulated subcarrier signal corresponding to any antenna to obtain a channel estimation result, perform channel equalization processing on each demodulated subcarrier signal according to the channel estimation result to obtain a first compensated subcarrier signal, and perform compensation processing on each first compensated subcarrier signal according to a difference between a local pilot subcarrier signal and a pilot compensated subcarrier signal in each first compensated subcarrier signal to obtain a second compensated subcarrier signal;

[0158] A determination module 1206 is configured to determine a target signal-to-noise ratio corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna, and determine a combining weight corresponding to each antenna according to the target signal-to-noise ratio;

[0159] The merging module 1208 is used to merge the second compensated subcarrier signals according to the merging weights corresponding to the antennas to obtain a combined signal, and perform data demodulation on the combined signal to obtain target data.

[0160] The OFDM signal processing device provided in the embodiment of the present application performs channel estimation and channel equalization on the subcarrier signals of each antenna respectively, and then further compensates and aligns each subcarrier signal according to the pilot signal, and then calculates the signal-to-noise ratio, and determines the merging weight of each antenna according to the signal-to-noise ratio, and after merging the subcarrier signals of each antenna according to the merging weight, the merged signal is demodulated to obtain the target data. The embodiment of the present application calculates the signal-to-noise ratio after compensating and aligning the subcarrier signals, which can eliminate the influence of the channel on the signal to the greatest extent, improve the calculation accuracy of the signal-to-noise ratio, and then improve the accuracy of the weight calculated when merging the antenna signals, so that the signal obtained after merging is more accurate. At the same time, the embodiment of the present application merges the subcarrier signals after aligning the subcarrier signals, which can avoid the problem of inconsistent subcarrier phases of different antennas, which affects data demodulation after merging, and improves the accuracy of the restored target data.

[0161] In one embodiment, the compensation module 1204 is further configured to:

[0162] Determine a pilot compensation subcarrier signal from each of the first compensation subcarrier signals;

[0163] Performing conjugate multiplication processing on each symbol in the local pilot subcarrier signal and each symbol in the pilot compensation subcarrier signal to obtain a phase difference between each symbol of the local pilot subcarrier signal and the pilot compensation subcarrier signal;

[0164] Determining a phase difference between the pilot compensation subcarrier signal and the local pilot subcarrier signal according to the phase difference corresponding to each of the symbols;

[0165] According to the phase difference between the pilot compensation subcarrier signal and the local pilot subcarrier signal, compensation processing is performed on each of the first compensation subcarrier signals to obtain a second compensation subcarrier signal.

[0166] In one embodiment, the receiving module 1202 is further configured to:

[0167] For any of the OFDM signals, perform timing coarse synchronization processing on the OFDM signal to obtain a frame start position of the OFDM signal, and perform compensation processing on the OFDM signal according to the frame start position and a phase difference between a plurality of consecutive short sequences in the OFDM signal to obtain a coarse frequency offset compensated OFDM signal;

[0168] For any of the coarse frequency offset compensated OFDM signals, perform timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol starting position of the coarse frequency offset compensated OFDM signal, and perform compensation processing on the coarse frequency offset compensated OFDM signal according to the symbol starting position and a phase difference between a plurality of continuous long sequences in the OFDM signal to obtain a fine frequency offset compensated OFDM signal;

[0169] Carrier demodulation processing is performed on each of the precise frequency offset compensated OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna.

[0170] In one embodiment, the receiving module 1202 is further configured to:

[0171] Generating a delayed signal corresponding to the OFDM signal, and performing conjugation processing on the OFDM signal to obtain a first conjugated signal;

[0172] Multiplying the delayed signal and the first conjugate signal to obtain a first correlation value between the delayed signal and the first conjugate signal, and accumulating the first correlation value in a first sliding window to obtain a first cumulative sum;

[0173] Multiplying the OFDM signal and the first conjugated signal to obtain a second correlation value between the OFDM signal and the first conjugated signal, and accumulating the second correlation value within the first sliding window to obtain a second cumulative sum;

[0174] The frame start position of the OFDM signal is determined according to a difference between the second accumulated sum and the first accumulated sum, and / or a ratio between the second accumulated sum and the first accumulated sum.

[0175] In one embodiment, the receiving module 1202 is further configured to:

[0176] Performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a second conjugate signal, and performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a third conjugate signal;

[0177] performing multiplication processing on the second conjugate signal and the coarse frequency offset compensated OFDM signal to obtain a third correlation value, and performing sliding correlation processing on the third conjugate signal and the coarse frequency offset compensated OFDM signal to obtain fourth correlation values ​​corresponding to different sliding values;

[0178] A symbol start position of the coarse frequency offset compensated OFDM signal is determined according to a difference between each of the fourth correlation values ​​and the third correlation value.

[0179] In one embodiment, the compensation module 1204 is further configured to:

[0180] Determining a pilot demodulated subcarrier signal from each of the demodulated subcarrier signals;

[0181] Performing conjugate multiplication processing on the pilot demodulation subcarrier signal and the local synchronization subcarrier signal to obtain a target pilot signal;

[0182] Performing inverse Fourier transform processing on the target pilot signal to obtain a time domain pilot signal, performing noise suppression processing on the time domain pilot signal, and performing Fourier transform on the time domain pilot signal after the noise suppression processing to obtain a denoised pilot signal;

[0183] A channel estimation result is obtained according to the target pilot signal and the denoised pilot signal.

[0184] In one embodiment, the determining module 1206 is further configured to:

[0185] Summing the target signal-to-noise ratios corresponding to the antennas to obtain a target signal-to-noise ratio sum;

[0186] For any of the antennas, a combining weight corresponding to the antenna is determined according to a ratio of the target signal-to-noise ratio corresponding to the antenna to the sum of the target signal-to-noise ratios.

[0187] Each module in the above device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0188] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Fig.13 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, an OFDM signal processing method is implemented.

[0189] Those skilled in the art will understand that Fig.13 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0190] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0191] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0192] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0193] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0194] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0195] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0196] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An OFDM signal processing method, characterized in that: The method comprises: Receiving OFDM signals through multiple antennas respectively, and performing carrier demodulation processing on each of the OFDM signals respectively, to obtain multiple demodulated subcarrier signals corresponding to each antenna; For any one of the antennas, perform channel estimation processing on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result, perform channel equalization processing on each of the demodulated subcarrier signals according to the channel estimation result to obtain a first compensation subcarrier signal, and perform compensation processing on each of the first compensation subcarrier signals according to a difference between a local pilot subcarrier signal and a pilot compensation subcarrier signal in each of the first compensation subcarrier signals to obtain a second compensation subcarrier signal; Determine a target signal-to-noise ratio corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna, and determine a combining weight corresponding to each antenna according to the target signal-to-noise ratio; The second compensated subcarrier signals are combined according to the combining weights corresponding to the antennas to obtain a combined signal, and the combined signal is demodulated to obtain target data.

2. The method according to claim 1, characterized in that The performing compensation processing on each of the first compensation subcarrier signals according to the difference between the local pilot subcarrier signal and the pilot compensation subcarrier signal in each of the first compensation subcarrier signals to obtain a second compensation subcarrier signal includes: Determine each pilot compensation subcarrier signal from each of the first compensation subcarrier signals; Performing conjugate multiplication processing on each of the pilot compensation subcarrier signals and the local pilot subcarrier signals corresponding to each of the pilot compensation subcarrier signals to obtain a target correlation value; A compensation phase difference is determined according to each of the target correlation values, and compensation processing is performed on each of the first compensation subcarrier signals according to the compensation phase difference to obtain a second compensation subcarrier signal.

3. The method according to claim 1, characterized in that The performing carrier demodulation processing on each of the OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna includes: For any of the OFDM signals, perform timing coarse synchronization processing on the OFDM signal to obtain a frame start position of the OFDM signal, and perform compensation processing on the OFDM signal according to the frame start position and a phase difference between a plurality of consecutive short sequences in the OFDM signal to obtain a coarse frequency offset compensated OFDM signal; For any of the coarse frequency offset compensated OFDM signals, perform timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol starting position of the coarse frequency offset compensated OFDM signal, and perform compensation processing on the coarse frequency offset compensated OFDM signal according to the symbol starting position and a phase difference between a plurality of continuous long sequences in the OFDM signal to obtain a fine frequency offset compensated OFDM signal; Carrier demodulation processing is performed on each of the precise frequency offset compensated OFDM signals to obtain a plurality of demodulated subcarrier signals corresponding to each antenna.

4. The method according to claim 3, characterized in that The performing timing coarse synchronization processing on the OFDM signal to obtain the frame start position of the OFDM signal includes: Generating a delayed signal corresponding to the OFDM signal, and performing conjugation processing on the OFDM signal to obtain a first conjugated signal; Multiplying the delayed signal and the first conjugate signal to obtain a first correlation value between the delayed signal and the first conjugate signal, and accumulating the first correlation value in a first sliding window to obtain a first cumulative sum; Multiplying the OFDM signal and the first conjugated signal to obtain a second correlation value between the OFDM signal and the first conjugated signal, and accumulating the second correlation value within the first sliding window to obtain a second accumulated sum; The frame start position of the OFDM signal is determined according to a difference between the second accumulated sum and the first accumulated sum, and / or a ratio between the second accumulated sum and the first accumulated sum.

5. The method according to claim 3, characterized in that: The performing timing fine synchronization processing on the coarse frequency offset compensated OFDM signal to obtain a symbol start position of the coarse frequency offset compensated OFDM signal includes: Performing conjugate processing on the coarse frequency offset compensated OFDM signal to obtain a second conjugate signal, and performing conjugate processing on the local synchronization sequence to obtain a third conjugate signal; performing multiplication processing on the second conjugate signal and the coarse frequency offset compensated OFDM signal to obtain a third correlation value, and performing sliding correlation processing on the third conjugate signal and the coarse frequency offset compensated OFDM signal to obtain fourth correlation values ​​corresponding to different sliding values; A symbol start position of the coarse frequency offset compensated OFDM signal is determined according to a difference between each of the fourth correlation values ​​and the third correlation value.

6. The method according to claim 1, characterized in that The performing channel estimation processing on each demodulated subcarrier signal corresponding to the antenna to obtain a channel estimation result includes: Determining a pilot demodulated subcarrier signal from each of the demodulated subcarrier signals; Performing conjugate multiplication processing on the pilot demodulation subcarrier signal and the local synchronization subcarrier signal to obtain a target pilot signal; Performing inverse Fourier transform processing on the target pilot signal to obtain a time domain pilot signal, performing noise suppression processing on the time domain pilot signal, and performing Fourier transform on the time domain pilot signal after the noise suppression processing to obtain a denoised pilot signal; A channel estimation result is obtained according to the target pilot signal and the denoised pilot signal.

7. The method according to claim 1, characterized in that Determining the combining weights corresponding to the antennas respectively according to the target signal-to-noise ratio includes: Summing the target signal-to-noise ratios corresponding to the antennas to obtain a target signal-to-noise ratio sum; For any of the antennas, a combining weight corresponding to the antenna is determined according to a ratio of the target signal-to-noise ratio corresponding to the antenna to the sum of the target signal-to-noise ratios.

8. An OFDM signal processing device, characterized in that: The device comprises: A receiving module, used to receive OFDM signals through multiple antennas respectively, and perform carrier demodulation processing on each of the OFDM signals respectively to obtain multiple demodulated subcarrier signals corresponding to each antenna; a compensation module, configured to perform channel estimation processing on each demodulated subcarrier signal corresponding to any antenna to obtain a channel estimation result, perform channel equalization processing on each demodulated subcarrier signal according to the channel estimation result to obtain a first compensated subcarrier signal, and perform compensation processing on each first compensated subcarrier signal according to a difference between a local pilot subcarrier signal and a pilot compensated subcarrier signal in each first compensated subcarrier signal to obtain a second compensated subcarrier signal; A determination module, configured to determine a target signal-to-noise ratio corresponding to each antenna according to each second compensation subcarrier signal corresponding to each antenna, and determine a combining weight corresponding to each antenna according to the target signal-to-noise ratio; The merging module is used to merge the second compensated subcarrier signals according to the merging weights corresponding to the antennas to obtain a merged signal, and perform data demodulation on the merged signal to obtain target data.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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