Method, system and storage medium for frequency deviation resistance in wireless data link

Abstract

The present invention discloses a method, system and storage medium for frequency deviation resistance in wireless data link. A method for frequency deviation resistance in wireless data link is applied to the coherent demodulation process of a demodulation device, including: for a modulated signal, a carrier frequency deviation is corrected by a fourth-power Costas loop with phase discrimination to recover the carrier signal, a Doppler frequency shift deviation range of about plus or minus 20Khz can be corrected by a fourth-power Coatas loop frequency discrimination, a channel estimation is given before the frequency deviation tracking and carrier recovery module of the system works, and a cross-product channel evaluation method can be used to adapt to the frequency deviation calibration caused by the Doppler frequency shift of high-speed equipment movement, and has the characteristics of effective signal carrier recovery capability, so as to solve the problem of huge frequency deviation caused by high speed communication between two devices, so as to ensure effective communication.

Description

Technical Field

[0001] The present invention relates to the field of wireless data link communication equipment in the field of wireless communications, and in particular to a method, system and storage medium for frequency deviation resistance in a wireless data link. Background Art

[0002] In wireless data link communications, the operating speed of many devices is getting faster and faster. The carrier speed has gradually developed from less than Mach 1 to Mach 10. Such a high rate has caused a huge frequency deviation for the communication between two devices. Here is a brief calculation of the frequency deviation value, assuming that the frequency deviation is completely caused by Doppler frequency shift and ignoring the frequency deviation caused by the crystals of the two devices [1]:

[0003] have:

[0004] When v = 10 Mach, carrier frequency F = 8 GHz, c is the speed of light, Δf = 91.67 Khz

[0005] Under such a large frequency deviation, ordinary communication can no longer meet the normal communication requirements, and some additional technical methods are urgently needed to achieve frequency deviation calibration. For coherent demodulation, the carrier signal needs to be restored in order to obtain demodulation performance. To restore the carrier signal, for systems with large dynamic Doppler frequency shift, it is necessary to correct the carrier frequency deviation and perform carrier recovery. Summary of the invention

[0006] The present invention provides a method, system and storage medium for resisting frequency deviation in a wireless data link, so as to solve the problem that a high rate generates a huge frequency deviation for communication between two devices, making it difficult to ensure effective communication.

[0007] In a first aspect, an embodiment of the present invention provides a method for resisting frequency deviation in a wireless data link, which is applied to a coherent demodulation process of a demodulation device, including: for a modulated signal, correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to restore the carrier signal.

[0008] Preferably, the frequency discrimination method adopted by the phase detector of the Costas loop is:

[0009] I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), using 4Δθ as the deviation for frequency calibration, wherein I(t) and Q(t) are the data after orthogonal down-conversion of the modulation signal of the QPSK type.

[0010] Preferably, the demodulation device obtains the Doppler frequency deviation value of the signal through channel evaluation;

[0011] Sending the Doppler frequency deviation value to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value;

[0012] The method of correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to recover the carrier signal specifically includes: starting the frequency deviation tracking and carrier recovery module of the demodulation device, and correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to recover the carrier signal.

[0013] Preferably, the demodulation device obtains the Doppler frequency deviation value of the signal through channel evaluation, which specifically includes: the transmitting end provides a pilot sequence before transmitting data information, wherein the pilot sequence is information greater than a preset time threshold sent according to a preset data code type;

[0014] The receiving end detects the pilot sequence to obtain a Doppler frequency deviation value of the pilot sequence;

[0015] Preferably, the pilot sequence sends information greater than 30us according to the code type 00110011.

[0016] Preferably, the obtaining the Doppler frequency deviation value of the pilot sequence specifically includes:

[0017] For the continuous sampling of the modulated signal, the IQ values ​​of two consecutive points α1 and α2 are (I1, Q1) and (I2, Q2), and we have:

[0018] tan(α2-α1)=(tanα2-tanα1) / (1+tanα2*tanα1)

[0019] =(Q2 / I2-Q1 / I1) / (1+Q2 / I2*Q1 / I1)

[0020] =(Q2I1-Q1I2) / (I1*I2+Q1*Q2)

[0021] When the sampling signal is dense, I1*I2+Q2*Q2 is approximately equal to 1, tan(α2-α1)=Q2I1-Q1I2, and after amplitude normalization, within the linear range: α2-α1 is approximately equal to tan(α2-α1)=Q2I1-Q1I2;

[0022] Define I(t)=sin(π / 4*n+2πfxΔt+θ0), Q(t)=cos(π / 4*n+2πfxΔt+θ0), where I(t) and Q(t) are the data after orthogonal down-conversion of the modulation signal of BPSK or QPSK type;

[0023] 2πfxΔt=α2-α1=Q2I1-Q1I2 Based on this, the cross product frequency calculation formula is obtained:

[0024] fx=(Q2I1-Q1I2)*c, where the constant c=1 / 2πΔt, Δt is the sampling period;

[0025] The Doppler frequency deviation value of the pilot sequence is obtained according to the cross product frequency calculation formula.

[0026] In a second aspect, the present invention provides a coherent demodulation process based on an anti-frequency deviation system in a wireless data link, applied to a demodulation device, including: a demodulation module, used to correct the carrier frequency deviation of the modulated signal through a fourth-power phase-locked Costas loop to restore the carrier signal.

[0027] Preferably, the frequency detection method adopted by the phase detector of the Costas loop is I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), and 4Δθ is used as the deviation for frequency calibration, wherein I(t) and Q(t) are the data after orthogonal down-conversion of the modulation signal of the =QPSK type.

[0028] Preferably, it also includes: a channel estimation module, used to obtain the Doppler frequency deviation value of the signal through channel evaluation;

[0029] A frequency preset module sends the Doppler frequency deviation value to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value;

[0030] The demodulation module is specifically used to: start the frequency deviation tracking and carrier recovery module of the demodulation device, and correct the carrier frequency deviation through the fourth-power phase-locked Costas loop to recover the carrier signal.

[0031] In a third aspect, the present invention further provides a computer storage medium, in which instructions are stored, and when the instructions are executed, the above-mentioned method for resisting frequency deviation in a wireless data link is executed.

[0032] The present invention uses a method, system and storage medium based on anti-frequency deviation in a wireless data link. The fourth-power Coatas loop frequency discrimination can correct the Doppler frequency shift deviation within a range of approximately plus or minus 20Khz. For large dynamic Doppler frequency shift, when the frequency shift reaches 90Khz or above, only relying on Costas and fourth-power frequency discrimination cannot effectively solve the problem. It is necessary to provide channel estimation before the frequency deviation tracking and carrier recovery modules of the system work. The cross-product channel evaluation method can adapt to the frequency deviation calibration caused by the Doppler frequency shift of high-speed equipment movement, and has the characteristic of effectively recovering the carrier wave capability of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a method for frequency deviation resistance in a wireless data link in Embodiment 1 of the present invention;

[0034] Figure 2It is a block diagram of the Costas ring principle in the first embodiment of the present invention;

[0035] Figure 3 It is a waveform diagram of a transmitted pilot signal and a signal after 60Khz Doppler frequency shift according to an example of an embodiment of the present invention;

[0036] Figure 4 A waveform diagram of the demodulation result after the channel estimation cross product algorithm and the fourth power deflection correction in an example of an embodiment of the present invention;

[0037] Figure 5 It is a structural block diagram of a frequency deviation resistance system in a wireless data link according to an example in the second embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0039] Embodiment 1

[0040] Figure 1-4 A flowchart of a method for resisting frequency deviation in a wireless data link provided in Embodiment 1 of the present invention is applied to a coherent demodulation process of a demodulation device, including: S11: for a modulated signal, correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to restore the carrier signal.

[0041] In this embodiment, the frequency discrimination method adopted by the phase detector of the Costas loop is:

[0042] I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), using 4Δθ as the deviation for frequency calibration, where I(t) and Q(t) are the data after orthogonal down-conversion of QPSK (Quadrature Phase Shift Keying) type modulation signals.

[0043] like Figure 2 As shown in the figure, the Costas loop is mainly composed of phase detector, loop filter, VCO (voltage controlled oscillator), low-pass filter and other modules. Among them, the phase detector is used to obtain the phase difference of the IQ signal; the loop filter is used to calculate and extract the phase difference; the VCO generates the corresponding local oscillator signal according to the phase difference and adjusts the down-converted signal. Through the continuous feedback iteration of the Costas loop, the entire loop can be locked and the carrier recovery of the corresponding signal can be completed.

[0044] Phase detector principle: The phase detector is used to obtain the phase difference function. Its phase detection method and phase detection performance directly determine the locking performance of the Costas loop. Commonly used Costas phase detectors include multiplication phase detectors, tangent phase detectors, and inverse tangent phase detectors. The effects of different phase detection methods are different. Taking BPSK (Binary Phase Shift Keying) and QPSK systems as examples, when selecting the actual phase detection method, it is also necessary to refer to the modulation method used. Different phase detection methods are used for different modulation methods. The present invention adopts the fourth power operation of the frequency detection method, which has a large amount of calculation and very ideal tracking performance. It is suitable for 20Khz frequency deviation and is used in QPSK systems.

[0045] Assume that the QPSK modulated signal is expressed as follows after down-conversion:

[0046] I(t)=sin(π / 4*n+2πfxΔt+θ0)...②

[0047] Q(t)=cos(π / 4*n+2πfxΔt+θ0)

[0048] Then: I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t))=1 / 2sin(2*π / 4*n+2*2πfxΔt+2*θ0)*cos(2*π / 4*n+2*2πfxΔt+2*θ0)=1 / 4sin(4*π / 4*n+4*2πfxΔt+4*θ0=1 / 4sinπ*n+8πfxΔt+4*θ0.

[0049] In the formula: after the π*n modulation symbol is multiplied by 4 times, it becomes an integer multiple of π, and the positive and negative signs are adjusted by the phase direction. The term 8πfxΔt is the phase change caused by the frequency deviation. When 8πfxΔt+4*θ0 is 0, the demodulator can normally track the phase change caused by the demodulation frequency deviation. Simplifying this term, let 8πfxΔt+4*θ0=4Δθ, then Δθ=2πfxΔt+θ0, where fx is the relative frequency deviation between devices, Δt is the sampling period, and θ0 is the initial phase. In the fourth power frequency detection method, 4Δθ is used as the deviation for frequency calibration, which is not affected by the signal characteristic data content and has fast frequency detection and tracking capability.

[0050] I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t))=1 / 4sin(π*n+4Δθ)...③

[0051] like Figure 1 As shown, in some implementations, for a high dynamic and large range Doppler frequency shift, how to quickly estimate the Doppler frequency shift within a limited signal length range is a key consideration.

[0052] For the above-mentioned carrier tracking and correction, the Doppler frequency shift deviation range that can be corrected is approximately plus or minus 20Khz. For large dynamic Doppler frequency shift, when the frequency shift reaches 90Khz and above, relying solely on Costas and fourth-power demodulation cannot effectively solve the problem, and channel estimation needs to be given before the system works.

[0053] Before S11, also including S12-S13:

[0054] S12: The demodulation device obtains the Doppler frequency deviation value of the signal through channel evaluation.

[0055] Among them, S12 includes S121-S122.

[0056] S121: The transmitting end provides a pilot sequence before transmitting data information, wherein the pilot sequence is to send information greater than a preset time threshold according to a preset data code pattern.

[0057] In this embodiment, in order to correctly evaluate the frequency deviation of the signal, a pilot sequence is provided before the transmitting end transmits the data information. The pilot sequence is information that is sent for more than 30us according to the code type of 00110011.

[0058] S122: The receiving end detects the pilot sequence and obtains the Doppler frequency deviation value of the pilot sequence.

[0059] In this embodiment, obtaining the Doppler frequency offset value of the pilot sequence specifically includes:

[0060] For continuous sampling of the modulated signal, the IQ values ​​of two consecutive points α1 and α2 are (I1, Q1) and (I2, Q2), and we have:

[0061] tan(α2-α1)=(tanα2-tanα1) / (1+tanα2*tana1)

[0062] =(Q2 / I2-Q1 / I1) / (1+Q2 / I2*Q1 / I1)

[0063] =(Q2I1-Q1I2) / (I1*I2+Q1*Q2)

[0064] When the sampling signal is dense, I1*I2+Q2*Q2 is approximately equal to 1, tan(α2-α1)=Q2I1-Q1I2, and after amplitude normalization, within the linear range: α2-α1 is approximately equal to tan(α2-α1)=Q2I1-Q1I2;

[0065] Define I(t)=sin(π / 4*n+2πfxΔt+θ0), Q(t)=cos(π / 4*n+2πfxΔt+θ0), where I(t) and Q(t) are the data after orthogonal down-conversion of the BPSK or QPSK type modulation signal;

[0066] 2πfxΔt=α2-α1=Q2I1-Q1I2 Based on this, the cross product frequency calculation formula is obtained:

[0067] fx=(Q2I1-Q1I2)*c...④

[0068] Wherein, constant c = 1 / 2πΔt, Δt is the sampling period;

[0069] The Doppler frequency deviation value of the pilot sequence is obtained according to the cross product frequency calculation formula.

[0070] S13 sends the Doppler frequency deviation value to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value.

[0071] S11 specifically includes: starting the frequency deviation tracking and carrier recovery module of the demodulation device, and correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to recover the carrier signal.

[0072] Due to the presence of frequency offset and multipath in the channel, the channel estimation algorithm largely determines the performance of the wireless communication system. The wireless channel has the characteristics of being non-fixed, highly random, and having a complex propagation path. In order to ensure the good performance of the receiving end in the wireless communication system, coherent demodulation is usually required, and a channel estimator with good performance is used to dynamically track the channel state changes. The data at the receiving end is corrected and restored according to the predicted channel characteristics to achieve data transmission with high reliability and low bit error rate. As one of the key technologies to ensure the performance of the wireless communication system, channel estimation mainly obtains accurate and detailed channel information, and then correctly demodulates the transmitted signal at the receiving end. Its performance is an important indicator for measuring the performance of a wireless communication system. The method for obtaining the channel estimation response information of the pilot position is relatively simple and single, but there are many methods for obtaining the subcarrier channel response of the data position through the subcarrier channel response of the pilot position, and different methods have different effects on the performance. In this embodiment, a channel estimation algorithm with good performance is explored from this perspective, which is of great significance to the improvement of the performance of the entire wireless mobile communication system.

[0073] The following examples illustrate the application and technical effects of the anti-frequency deviation method: Figure 3-4 ,in, Figure 3 To transmit the pilot signal and the signal after 60Khz Doppler frequency shift, Figure 4It is the result of demodulation after the QPSK signal passes through a 60Khz (this example is used to describe the processing flow of Doppler frequency shift) Doppler frequency shift, and cross product evaluation and fourth-power correction are performed at the demodulation end: daI_in and daQ_in are the input signals after Doppler frequency shift, cos and sin are the output signals of VCO, which are used to track external frequency deviation, da_firI and da_firQ are the IQ demodulated signals restored after correction. It can be seen from the figure that the Doppler frequency shift of the original signal no longer exists, and is removed by the cross product evaluation and fourth-power correction. syn_01 is the demodulated frame synchronization signal, databefover is the calibration signal after demodulation, and the generated pulse indicates that the demodulator output is correct.

[0074] Embodiment 2

[0075] like Figure 5 As shown, the present invention also provides an anti-frequency deviation system in a wireless data link, including: a coherent demodulation process applied to a demodulation device, including: a demodulation module 21, which is used to correct the carrier frequency deviation of the modulated signal through a Costas loop with a fourth-power phase detection to restore the carrier signal.

[0076] In this embodiment, the frequency discrimination method adopted by the phase detector of the Costas loop is:

[0077] I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), using 4Δθ as the deviation for frequency calibration, where I(t) and Q(t) are the data after orthogonal down-conversion of the QPSK type modulation signal.

[0078] In some implementations, a channel estimation module 22 is further included, configured to obtain a Doppler frequency deviation value of a signal through channel evaluation.

[0079] In this embodiment, in order to correctly evaluate the frequency deviation of the signal, a pilot sequence is provided before the transmitting end transmits the data information. The pilot sequence is information that is sent for more than 30us according to the code type of 00110011.

[0080] In this embodiment, obtaining the Doppler frequency offset value of the pilot sequence specifically includes:

[0081] For continuous sampling of the modulated signal, the IQ values ​​of two consecutive points α1 and α2 are (I1, Q1) and (I2, Q2), and we have:

[0082] tan(α2-α1)=(tanα2-tanα1) / (1+tanα2*tana1)

[0083] =(Q2 / I2-Q1 / I1) / (1+Q2 / I2*Q1 / I1)

[0084] =(Q2I1-Q1I2) / (I1*I2+Q1*Q2)

[0085] When the sampling signal is dense, I1*I2+Q2*Q2 is approximately equal to 1, tan(a2-a1)=Q2I1-Q1I2, and after amplitude normalization, within the linear range: α2-α1 is approximately equal to tan(α2-α1)=Q2I1-Q1I2;

[0086] Define I(t)=sin(π / 4*n+2πfxΔt+θ0), Q(t)=cos(π / 4*n+2πfxΔt+θ0), where I(t) and Q(t) are the data after orthogonal down-conversion of the BPSK or QPSK type modulation signal;

[0087] 2πfxΔt=α2-α1=Q2I1-Q1I2 Based on this, the cross product frequency calculation formula is obtained:

[0088] fx=(Q2I1-Q1I2)*c Wherein, constant c=1 / 2πΔt, Δt is the sampling period;

[0089] The Doppler frequency deviation value of the pilot sequence is obtained according to the cross product frequency calculation formula.

[0090] The frequency preset module 23 sends the Doppler frequency deviation value to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value.

[0091] The demodulation module 21 is specifically used to start the frequency deviation tracking and carrier recovery module of the demodulation device, and correct the carrier frequency deviation through the fourth-power phase-locked Costas loop to recover the carrier signal.

[0092] The system of this embodiment can execute any of the frequency deviation resistance methods in the wireless data link provided in the aforementioned embodiments, and thus can also achieve the corresponding technical effects, which have been described in detail above and will not be repeated here.

[0093] An embodiment of the present invention also provides a computer device, including a processor and a memory; the memory is used to store computer instructions, and the processor is used to run the computer instructions stored in the memory to execute any one of the sewage treatment process remote control methods provided in the aforementioned embodiments, thereby also being able to achieve the corresponding technical effects, which have been described in detail above and will not be repeated here.

[0094] Correspondingly, an embodiment of the present invention also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed, any one of the remote control methods for sewage treatment processes provided in the aforementioned embodiments is executed, thereby also being able to achieve the corresponding technical effects, which have been described in detail above and will not be repeated here.

[0095] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0096] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods of various embodiments of the present invention.

[0097] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for frequency deviation resistance in a wireless data link, characterized in that: A coherent demodulation process applied to a demodulation device includes: for a modulated signal, correcting a carrier frequency deviation through a fourth-power phase-detection Costas loop to restore a carrier signal; The demodulation device obtains the Doppler frequency deviation value of the signal through channel evaluation, which specifically includes: the transmitting end provides a pilot sequence before transmitting data information, wherein the pilot sequence is information that is sent greater than a preset time threshold according to a preset data code pattern; the receiving end detects the pilot sequence to obtain the Doppler frequency deviation value of the pilot sequence; The Doppler frequency deviation value of the pilot sequence includes: For continuous sampling of the modulated signal, the IQ values ​​of two consecutive points α1 and α2 are (I1, Q1) and (I2, Q2), and we have: tan(α2-α1)=(tanα2-tanα1) / (1+tanα2*tanα1) =(Q2 / I2-Q1 / I1) / (1+Q2 / I2*Q1 / I1) =(Q2I1-Q1I2) / (I1*I2+Q1*Q2) When the sampling signal is dense, I1*I2+Q2*Q2 is approximately equal to 1, tan(α2-α1)=Q2I1-Q1I2, and after amplitude normalization, within the linear range: α2-α1 is approximately equal to tan(α2-α1)=Q2I1-Q1I2; Define I(t)=sin(π / 4*n+2πfxΔt+θ0), Q(t)=cos(π / 4*n+2πfxΔt+θ0), where I(t) and Q(t) are the data after orthogonal down-conversion of the BPSK or QPSK type modulation signal; 2πfxΔt=α2-α1=Q2I1-Q1I2 Based on this, the cross product frequency calculation formula is obtained: fx=(Q2I1-Q1I2)*c, where the constant c=1 / 2πΔt, Δt is the sampling period; The Doppler frequency deviation value of the pilot sequence is obtained according to the cross product frequency calculation formula.

2. The method for anti-frequency deviation in a wireless data link according to claim 1, characterized in that: The frequency detection method adopted by the phase detector of the Costas loop is I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), and 4Δθ is used as the deviation for frequency calibration, wherein I(t) and Q(t) are data after orthogonal down-conversion of the QPSK type modulation signal.

3. The method for anti-frequency deviation in a wireless data link according to claim 1 or 2, characterized in that: The demodulation device obtains the Doppler frequency deviation value of the signal through channel evaluation; The Doppler frequency deviation value is sent to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value; Correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to recover the carrier signal specifically includes: starting a frequency deviation tracking and carrier recovery module of a demodulation device, and correcting the carrier frequency deviation through a fourth-power phase-locked Costas loop to recover the carrier signal.

4. The method for resisting frequency deviation in a wireless data link according to claim 1, characterized in that: The pilot sequence sends information greater than 30us according to the code type 00110011.

5. A system for implementing the method for anti-frequency deviation in a wireless data link according to claim 1, characterized in that: A coherent demodulation process applied to a demodulation device includes: a demodulation module for correcting carrier frequency deviation of a modulated signal through a fourth-power phase-locked Costas loop to restore a carrier signal.

6. The system according to claim 5, characterized in that The frequency detection method adopted by the phase detector of the Costas loop is I(t)Q(t)*(I(t)-Q(t))(I(t)+Q(t)), and 4Δθ is used as the deviation for frequency calibration, wherein I(t) and Q(t) are data after orthogonal down-conversion of the QPSK type modulation signal.

7. The system according to claim 5 or 6, characterized in that Also includes: A channel estimation module, used for obtaining a Doppler frequency deviation value of a signal through channel evaluation; The frequency preset module sends the Doppler frequency deviation value to the frequency deviation tracking and carrier recovery module of the demodulation device as a frequency preset value; The demodulation module is specifically used to: start the frequency deviation tracking and carrier recovery module of the demodulation device, and correct the carrier frequency deviation through the fourth-power phase-locked Costas loop to recover the carrier signal.

8. A computer storage medium, characterized in that The storage medium stores instructions, and when the instructions are executed, a method for resisting frequency deviation in a wireless data link according to any one of claims 1 to 4 is executed.

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