Frequency offset estimation method and device and storage medium

Abstract

The invention provides a frequency offset estimation method and device and a storage medium, and relates to the technical field of wireless communication, and the method comprises the steps: obtaining each pilot symbol of a received signal; performing conjugate point multiplication on the pilot symbols and a local pilot sequence to obtain response estimated values of all channels; for any symbol interval, determining a target pilot symbol pair corresponding to the symbol interval; for each target pilot symbol pair, performing conjugate multiplication on the channel response estimation values of the two pilot symbols in the target pilot symbol pair to obtain a cross-correlation result; obtaining a target cross-correlation result based on all the cross-correlation results; when the target cross-correlation result is one of a plurality of preset special values, determining a phase corresponding to the corresponding special value as a target phase; the special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system; and calculating the frequency offset by using the target phase and the symbol interval of the target pilot symbol pair. According to the invention, the storage space of the tangent table can be reduced, and meanwhile, the frequency offset estimation precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a frequency offset estimation method, device and storage medium. Background Art

[0002] In wireless communication scenarios, when the local oscillator frequency of the receiving end is different from that of the transmitting end, there will be a difference between the received signal frequency and the transmitted signal frequency, which is called frequency offset. The existence of frequency offset will affect the quality of the received signal and the performance of the entire communication system. Therefore, frequency offset estimation is required, and the accuracy and complexity of frequency offset estimation directly affect the efficiency and cost of the system.

[0003] In existing engineering implementation technology, a tangent table of phase (0, π / 2) is usually prepared, the phase is estimated by table lookup, and then the frequency offset value is calculated based on the phase. However, considering the size of the storage table, the existing technology adopts a method of preparing the tangent table according to a certain phase step size. Although this method can reduce the storage space of the tangent table, it will sacrifice the accuracy of frequency offset estimation.

[0004] Based on this, how to reduce the storage space of the tangent table and improve the accuracy of frequency offset estimation has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, in order to solve the above technical problem, the present invention provides a frequency offset estimation method, device and storage medium.

[0006] The present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a frequency offset estimation method, comprising:

[0008] Acquire a pilot symbol set of a received signal, wherein the pilot symbol set includes a plurality of pilot symbols;

[0009] Performing conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol;

[0010] For any symbol interval, determine all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is a symbol interval between two pilot symbols in the target pilot symbol pair;

[0011] For each of the target pilot symbol pairs, conjugate multiply the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair to obtain a cross-correlation result of the target pilot symbol pair;

[0012] Based on all the cross-correlation results, a target cross-correlation result is obtained;

[0013] Determine whether the target cross-correlation result is one of a plurality of preset special values; the special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system;

[0014] If the target cross-correlation result is one of a plurality of preset special values, the phase corresponding to the special value is determined as the target phase;

[0015] A frequency offset is calculated using the target phase and the symbol interval of the target pilot symbol pair.

[0016] Optionally, after determining whether the target cross-correlation result is one of a plurality of preset special values, the frequency offset estimation method of the present invention further includes:

[0017] If the target cross-correlation result is not one of the preset multiple special values, then based on the conversion relationship between tangent and cotangent, calculate the tangent value according to the target cross-correlation result;

[0018] Determining a first temporary phase according to the tangent value;

[0019] Based on the conversion relationship between tangent and cotangent, and according to the first temporary phase, a second temporary phase is determined;

[0020] The target phase is determined according to the second temporary phase and the sign bits of the real part and the imaginary part of the target cross-correlation result.

[0021] Optionally, based on the conversion relationship between tangent and cotangent and according to the target cross-correlation result, the tangent value is calculated, specifically including:

[0022] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, the tangent value is calculated using the following formula:

[0023] tanA=Im(CorrValue) / Re(CorrValue)

[0024] Wherein, tanA represents the tangent value, CorrValue represents the target cross-correlation result, Im() represents taking the imaginary part of the target cross-correlation result, and Re() represents taking the real part of the target cross-correlation result;

[0025] When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus, the tangent value is calculated using the following formula:

[0026] tanA=Re(CorrValue) / Im(CorrValue).

[0027] Optionally, based on the conversion relationship between tangent and cotangent and according to the first temporary phase, determining the second temporary phase specifically includes:

[0028] When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus thereof, the second temporary phase is obtained by calculating the difference between π / 2 and the first temporary phase;

[0029] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, it is determined that the second temporary phase is equal to the first temporary phase.

[0030] Optionally, determining the first temporary phase according to the tangent value specifically includes:

[0031] Determining whether the tangent value is less than or equal to a preset threshold;

[0032] If the tangent value is less than or equal to a preset threshold, determining that the first temporary phase is equal to the tangent value;

[0033] If the tangent value is greater than a preset threshold, the first temporary phase is determined by querying a preset tangent table.

[0034] Optionally, determining the target phase according to the sign bits of the real part and the imaginary part of the second temporary phase and the target cross-correlation result specifically includes:

[0035] When the real part and the imaginary part of the target cross-correlation result are both greater than 0, determining that the target phase is equal to the second temporary phase;

[0036] When the real part of the target cross-correlation result is less than 0 and the imaginary part thereof is greater than 0, the target phase is obtained by calculating the difference between π and the second temporary phase;

[0037] When the real part and the imaginary part of the target cross-correlation result are both less than 0, the target phase is obtained by calculating the difference between the second temporary phase and π;

[0038] When the real part of the target cross-correlation result is greater than 0 and the imaginary part thereof is less than 0, the target phase is determined to be equal to the negative number of the second temporary phase.

[0039] Optionally, obtaining a target cross-correlation result based on all the cross-correlation results specifically includes:

[0040] When the number of the cross-correlation results is 1, determining the cross-correlation result as the target cross-correlation result;

[0041] When there are multiple cross-correlation results, the target cross-correlation result is obtained by taking an average value of all the cross-correlation results.

[0042] In a second aspect, the present invention further provides a frequency offset estimation device, comprising:

[0043] An acquisition module, configured to acquire a pilot symbol set of a received signal, wherein the pilot symbol set includes a plurality of pilot symbols;

[0044] A conjugate point multiplication module, used for performing conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol;

[0045] A first determination module is used to determine, for any symbol interval, all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is a symbol interval between two pilot symbols in the target pilot symbol pair;

[0046] A conjugate multiplication module, configured to conjugate multiply the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair for each target pilot symbol pair, so as to obtain a cross-correlation result of the target pilot symbol pair;

[0047] A first calculation module, configured to obtain a target cross-correlation result based on all the cross-correlation results;

[0048] A judgment module, used for judging whether the target cross-correlation result is one of a plurality of preset special values; the special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system;

[0049] A second determination module is used to determine the phase corresponding to the special value as the target phase if the target cross-correlation result is one of a plurality of preset special values;

[0050] The second calculation module is used to calculate the frequency offset using the target phase and the symbol interval of the target pilot symbol pair.

[0051] In a third aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the various steps in the frequency offset estimation method as described above are implemented.

[0052] The present invention adopts the above technical scheme, a frequency offset estimation method, comprising: obtaining a pilot symbol set of a received signal, the pilot symbol set including multiple pilot symbols; performing conjugate point multiplication on the pilot symbol and a local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol; for any symbol interval, determining all target pilot symbol pairs corresponding to the symbol interval, the symbol interval being the symbol interval between two pilot symbols in the corresponding target pilot symbol pair; for each target pilot symbol pair, performing conjugate multiplication on the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair to obtain a cross-correlation result of the target pilot symbol pair; obtaining a target cross-correlation result based on all cross-correlation results; judging whether the target cross-correlation result is one of multiple preset special values; the special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system; if the target cross-correlation result is one of multiple preset special values, determining the phase corresponding to the corresponding special value as the target phase; and calculating the frequency offset using the target phase and the symbol interval of the target pilot symbol pair.

[0053] Based on this, by judging whether the target cross-correlation result is one of multiple preset special values, the special value is a value located on the coordinate axis of the two-dimensional Cartesian coordinate system. If the target cross-correlation result is one of the multiple preset special values, the phase corresponding to the special value is determined as the target phase, rather than obtaining the target phase by querying the tangent table. This makes it unnecessary for the present invention to store a table of phases corresponding to special values, reduces the storage space of the tangent table, and, because the table lookup method sacrifices a certain degree of accuracy, the method of determining the phase corresponding to the special value as the target phase can obtain a more accurate target phase, so that the present invention also improves the accuracy of frequency offset estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 is a flow chart of a frequency offset estimation method provided by an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of a table lookup range provided by an embodiment of the present invention;

[0057] Figure 3 It is a structural schematic diagram of a frequency offset estimation device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0059] In wireless communication scenarios, when the local oscillator frequency of the receiving end is different from that of the transmitting end, there will be a difference between the received signal frequency and the transmitted signal frequency, which is called frequency offset. The existence of frequency offset will affect the quality of the received signal and the performance of the entire communication system. Therefore, frequency offset estimation is required, and the accuracy and complexity of frequency offset estimation directly affect the efficiency and cost of the system.

[0060] In existing engineering implementation technology, a tangent table of phase (0, π / 2) is usually prepared, the phase is estimated by table lookup, and then the frequency offset value is calculated based on the phase. However, considering the size of the storage table, the existing technology adopts a method of preparing the tangent table according to a certain phase step size. Although this method can reduce the storage space of the tangent table, it will sacrifice the accuracy of frequency offset estimation.

[0061] Based on this, in order to reduce the storage space of the tangent table and improve the accuracy of frequency offset estimation, the present invention provides a frequency offset estimation method, device and storage medium.

[0062] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0063] Figure 1 FIG. 1 is a flow chart of a frequency offset estimation method provided by an embodiment of the present invention. The frequency offset estimation method can be applied to a signal receiving end. Figure 1 As shown, the frequency offset estimation method includes:

[0064] Step 101: Acquire a pilot symbol set of a received signal, where the pilot symbol set includes a plurality of pilot symbols.

[0065] Specifically, in an OFDM (Orthogonal Frequency Division Multiplexing) system, the received time domain signal is subjected to a CP (Cyclic Prefix) removal operation. Then, the FFT (Fast Fourier Transformation) algorithm is applied to convert the time domain signal to the frequency domain to obtain a frequency domain signal. Next, pilot symbols are extracted from the frequency domain signal to obtain a pilot symbol set of the received signal.

[0066] Step 102: Perform conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value H_LS(l,k) corresponding to each pilot symbol.

[0067] Wherein, l represents the index of the pilot symbol, and k represents the index of the subcarrier. H_LS(l,k) represents the channel response estimation value calculated by the least square method at l and k, which is a complex number.

[0068] Step 103: for any symbol interval, determine all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is the symbol interval between two pilot symbols in the corresponding target pilot symbol pair.

[0069] Specifically, the symbol interval of the pilot symbol is fixed and known, and the frequency offset results can be calculated for different symbol intervals. The embodiment of the present invention is described by taking the calculation of the frequency offset result for any symbol interval as an example.

[0070] For any symbol interval t, all target pilot symbol pairs corresponding to the symbol interval are determined, that is, the pilot symbol pair with the symbol interval of the current symbol interval is determined as the target pilot symbol pair. In a specific example, for symbol interval 4, the corresponding target pilot symbol pairs may be (pilot symbol 0, pilot symbol 4) and (pilot symbol 7, pilot symbol 11), wherein the symbol interval between pilot symbol 0 and pilot symbol 4 is equal to 4, and the symbol interval between pilot symbol 7 and pilot symbol 11 is also equal to 4.

[0071] Step 104: For each target pilot symbol pair, conjugate multiply the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair to obtain a cross-correlation result of the target pilot symbol pair.

[0072] Specifically, for each target pilot symbol pair, the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair are conjugate multiplied using the following calculation formula to obtain the cross-correlation result CorrValueTmp(k) of the target pilot symbol pair:

[0073] CorrValueTmp(k)=H_LS(l 1,k).*conj(H_LS(l0,k))...... (1)

[0074] Wherein, conj() indicates calculating the conjugate value of a complex number, and l1 and l0 constitute a target pilot symbol pair.

[0075] Step 105: Based on all the cross-correlation results, a target cross-correlation result is obtained.

[0076] Specifically, when the number of the cross-correlation results is 1, the cross-correlation result is determined to be the target cross-correlation result CorrValue.

[0077] When there are multiple cross-correlation results, the target cross-correlation result CorrValue is obtained by averaging all the cross-correlation results, that is, CorrValue=mean(CorrValueTmp(k)), where mean() represents the calculated average value. In this way, by averaging more cross-correlation results, noise reduction can be achieved, making the frequency offset estimation result more accurate.

[0078] Step 106: Determine whether the target cross-correlation result is one of a plurality of preset special values, if the target cross-correlation result is one of a plurality of preset special values, execute step 107. The special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system.

[0079] Specifically, there are 4 special values, which are:

[0080] Special value 1: The real part of CorrValue is equal to 0, and the imaginary part is greater than 0, that is, Re(CorrValue) = 0, and Im(CorrValue)> 0, at this time, CorrValue is located in the positive direction of the y axis. Re() means taking the real part of the complex number, and Im() means taking the imaginary part of the complex number.

[0081] Special value 2: Re(CorrValue)=0, and Im(CorrValue)<0. In this case, CorrValue is in the negative direction of the y-axis.

[0082] Special value 3: Re(CorrValue)<0, and Im(CorrValue)=0. In this case, CorrValue is located in the negative direction of the x-axis.

[0083] Special value 4: Re(CorrValue)>0, and Im(CorrValue)=0. At this time, CorrValue is located in the positive direction of the x-axis.

[0084] Step 107: Determine the phase corresponding to the special value as the target phase.

[0085] Specifically, when Re(CorrValue)=0 and Im(CorrValue)>0, the target phase θ is determined final =π / 2.

[0086] When Re(CorrValue)=0 and Im(CorrValue)<0, determine the target phase θ final =-π / 2.

[0087] When Re(CorrValue)<0 and Im(CorrValue)=0, determine the target phase θ final =π.

[0088] When Re(CorrValue)>0 and Im(CorrValue=0, determine the target phase θ final =0.

[0089] Step 108: Calculate the frequency offset using the target phase and the symbol interval of the target pilot symbol pair.

[0090] Specifically, the target phase θ final Substitute the symbol interval t of the target pilot symbol pair into the following formula to obtain the frequency offset Δf:

[0091]

[0092] It should be noted that after the frequency deviation Δf of each symbol interval t is obtained by executing the above scheme, the frequency deviation Δf of each symbol interval t can be post-processed, such as directly averaging or weighted averaging, to finally obtain a more accurate target frequency deviation.

[0093] The embodiment of the present invention adopts the above-mentioned technical solution, by judging whether the target cross-correlation result is one of multiple preset special values, where the special value is a value located on the coordinate axis of the two-dimensional Cartesian coordinate system. If the target cross-correlation result is one of the multiple preset special values, the phase corresponding to the special value is determined as the target phase, rather than obtaining the target phase by querying the tangent table. This makes it unnecessary for the present invention to store a table for the phase corresponding to the special value, reducing the storage space of the tangent table. In addition, since the table lookup method will sacrifice a certain degree of accuracy, the method of determining the phase corresponding to the special value as the target phase can obtain a more accurate target phase, so that the present invention also improves the accuracy of frequency offset estimation.

[0094] In the embodiment of the present invention, after determining whether the target cross-correlation result is one of a plurality of preset special values, the frequency offset estimation method of the present invention further includes:

[0095] (1) If the target cross-correlation result is not one of the preset multiple special values, the tangent value is calculated according to the target cross-correlation result based on the conversion relationship between tangent and cotangent.

[0096] Specifically, tangent and cotangent are reciprocals of each other, so we get:

[0097]

[0098] Here, based on the conversion relationship between tangent and cotangent and according to the target cross-correlation result, the tangent value is calculated, which may specifically include:

[0099] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus, the tangent value is calculated using the following formula:

[0100] tanA=Im(CorrValue) / Re(CorrValue)...... (4)

[0101] Among them, tanA represents the tangent value, CorrValue represents the target cross-correlation result, Im() represents taking the imaginary part of the target cross-correlation result, and Re() represents taking the real part of the target cross-correlation result.

[0102] When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus, the tangent value is calculated using the following formula:

[0103] tanA=Re(CorrValue) / Im(CorrValue)...... (5)

[0104] (2) Determine the first temporary phase according to the tangent value.

[0105] Specifically, determining the first temporary phase according to the tangent value may include:

[0106] (2.1) Determine whether the tangent value is less than or equal to the preset threshold Thresh.

[0107] Here, the specific value of the preset threshold Thresh can be set by those skilled in the art according to actual conditions, and the present invention does not make any specific limitation here. It can be understood that the smaller the value of the preset threshold Thresh is, the more conducive it is to improving the accuracy of the frequency offset estimation result.

[0108] (2.2) If the tangent value is less than or equal to the preset threshold, the first temporary phase is determined to be equal to the tangent value; if the tangent value is greater than the preset threshold, the first temporary phase is determined by querying a preset tangent table.

[0109] Specifically, it is well known to those skilled in the art that when the phase is relatively small, its corresponding tangent value and the phase itself are equivalent to infinitesimals. At this time, the phase can be directly equal to its corresponding tangent value, so this section does not need to be stored in a table, and the accuracy is higher than the table lookup method.

[0110] Based on this, Figure 2 Schematic diagram of a table lookup range provided by an embodiment of the present invention. Figure 2 As shown, in an embodiment of the present invention, when the tangent value is less than or equal to a preset threshold, that is, when the phase is relatively small, it is determined that the first temporary phase is equal to the tangent value (at this time, there is no need to look up a table); when the tangent value is greater than the preset threshold, the first temporary phase is determined by querying the preset tangent table.

[0111] It should be noted that the prior art is to determine the first temporary phase by querying a preset tangent table. When the tangent table is a table of equally spaced phases, [tan(θ s ), tan(θ s +Δθ1),tan(θ s +2Δθ1), ...], given θ s and Δθ1, and the first temporary phase is deduced from tanA. When the tangent table is made for unequally spaced phases, the first temporary phase is deduced from the piecewise function expression.

[0112] (3) Based on the conversion relationship between tangent and cotangent, the second temporary phase θ1 is determined according to the first temporary phase θ0.

[0113] Specifically, when the real part modulus of the target cross-correlation result is greater than the imaginary part modulus thereof, the second temporary phase is obtained by calculating the difference between π / 2 and the first temporary phase, that is, θ1=π / 2-θ0.

[0114] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, it is determined that the second temporary phase is equal to the first temporary phase, that is, θ1=θ0.

[0115] (4) Determine the target phase θ according to the sign bits of the real and imaginary parts of the second temporary phase and the target cross-correlation result final .

[0116] Specifically, when the real part and the imaginary part of the target cross-correlation result are both greater than 0, it is determined that the target phase is equal to the second temporary phase; that is, when Re(CorrValue)>0 and Im(CorrValue)>0, θ final =θ1.

[0117] When the real part of the target cross-correlation result is less than 0 and its imaginary part is greater than 0, the target phase is obtained by calculating the difference between π and the second temporary phase; that is, when Re(CorrValue)<0 and Im(CorrValue)>0, θ final =π-θ1.

[0118] When both the real and imaginary parts of the target cross-correlation result are less than 0, the target phase is obtained by calculating the difference between the second temporary phase and π; that is, when Re(CorrValue)<0 and Im(CorrValue)<0, θ final =θ1-π.

[0119] When the real part of the target cross-correlation result is greater than 0 and its imaginary part is less than 0, the target phase is determined to be equal to the negative of the second temporary phase. That is, when Re(CorrValue)>0 and Im(CorrValue)<0, θ final =-θ1.

[0120] The embodiment of the present invention adopts the above technical solution, and sets a preset threshold by utilizing the property of equivalent infinitesimals. When the tangent value is less than or equal to the preset threshold, the first temporary phase is directly determined to be equal to the tangent value without looking up the table, so that the present invention can reduce the storage space of the tangent table, save the amount of calculation for table lookup, improve the calculation efficiency and reduce the calculation cost, and ensure the accuracy of the frequency deviation estimation result to a certain extent. In addition, the present invention utilizes the conversion relationship between tangent and cotangent, so that the tangent table only needs to reach π / 4, and the remaining (π / 4, π / 2) can be converted by tangent and cotangent, and the table size is further reduced by half, that is, the storage space is saved by half.

[0121] Based on a general inventive concept, the present invention also provides a frequency offset estimation device. Figure 3 FIG. 1 is a schematic diagram of the structure of a frequency offset estimation device provided by an embodiment of the present invention. Figure 3 As shown, the device comprises:

[0122] An acquisition module 31 is used to acquire a pilot symbol set of a received signal, where the pilot symbol set includes a plurality of pilot symbols;

[0123] A conjugate point multiplication module 32 is used to perform conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol;

[0124] A first determination module 33 is used to determine, for any symbol interval, all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is a symbol interval between two pilot symbols in the corresponding target pilot symbol pair;

[0125] A conjugate multiplication module 34 is used to perform conjugate multiplication on the channel response estimation values ​​of two pilot symbols in the target pilot symbol pair for each target pilot symbol pair to obtain a cross-correlation result of the target pilot symbol pair;

[0126] A first calculation module 35, used to obtain a target cross-correlation result based on all cross-correlation results;

[0127] A judgment module 36 is used to judge whether the target cross-correlation result is one of a plurality of preset special values; the special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system;

[0128] A second determination module 37 is used to determine the phase corresponding to the special value as the target phase if the target cross-correlation result is one of a plurality of preset special values;

[0129] The second calculation module 38 is used to calculate the frequency offset using the target phase and the symbol interval of the target pilot symbol pair.

[0130] Optionally, the frequency offset estimation device of the present invention may further include:

[0131] The third calculation module is used to calculate the tangent value according to the target cross-correlation result based on the conversion relationship between tangent and cotangent if the target cross-correlation result is not one of the preset multiple special values.

[0132] The third determining module is used to determine a first temporary phase according to the tangent value.

[0133] The fourth determination module is used to determine the second temporary phase according to the first temporary phase based on the conversion relationship between the tangent and the cotangent.

[0134] The fifth determination module is used to determine the target phase according to the sign bits of the real part and the imaginary part of the second temporary phase and the target cross-correlation result.

[0135] Optionally, the third computing module may be specifically used for:

[0136] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, the tangent value is calculated using the following formula:

[0137] tanA=Im(CorrValue) / Re(CorrValue)

[0138] Among them, tanA represents the tangent value, CorrValue represents the target cross-correlation result, Im() represents taking the imaginary part of the target cross-correlation result, and Re() represents taking the real part of the target cross-correlation result.

[0139] When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus, the tangent value is calculated using the following formula:

[0140] tanA=Re(CorrValue) / Im(CorrValue).

[0141] Optionally, the fourth determining module may be specifically used for:

[0142] When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus thereof, the second temporary phase is obtained by calculating the difference between π / 2 and the first temporary phase.

[0143] When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, it is determined that the second temporary phase is equal to the first temporary phase.

[0144] Optionally, the third determination module may be specifically used for:

[0145] (1) Determine whether the tangent value is less than or equal to a preset threshold.

[0146] (2) If the tangent value is less than or equal to a preset threshold, determining that the first temporary phase is equal to the tangent value; if the tangent value is greater than the preset threshold, determining the first temporary phase by querying a preset tangent table.

[0147] Optionally, the fifth determining module may be specifically used for:

[0148] When the real part and the imaginary part of the target cross-correlation result are both greater than 0, it is determined that the target phase is equal to the second temporary phase.

[0149] When the real part of the target cross-correlation result is less than 0 and the imaginary part thereof is greater than 0, the target phase is obtained by calculating the difference between π and the second temporary phase.

[0150] When the real part and the imaginary part of the target cross-correlation result are both less than 0, the target phase is obtained by calculating the difference between the second temporary phase and π.

[0151] When the real part of the target cross-correlation result is greater than 0 and the imaginary part thereof is less than 0, the target phase is determined to be equal to the negative number of the second temporary phase.

[0152] Optionally, the first calculation module 35 may be specifically used for:

[0153] When the number of the cross-correlation results is 1, the cross-correlation result is determined to be the target cross-correlation result.

[0154] When there are multiple cross-correlation results, the target cross-correlation result is obtained by taking an average value of all the cross-correlation results.

[0155] Based on a general inventive concept, the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, each step in the frequency offset estimation method described above is implemented.

[0156] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0157] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0158] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0159] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0160] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0161] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0162] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0163] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0164] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A frequency offset estimation method, characterized in that: include: Acquire a pilot symbol set of a received signal, wherein the pilot symbol set includes a plurality of pilot symbols; Performing conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol; For any symbol interval, determine all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is a symbol interval between two pilot symbols in the target pilot symbol pair; For each of the target pilot symbol pairs, conjugate multiply the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair to obtain a cross-correlation result of the target pilot symbol pair; Based on all the cross-correlation results, a target cross-correlation result is obtained; Determining whether the target cross-correlation result is one of a plurality of preset special values; The special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system; If the target cross-correlation result is one of a plurality of preset special values, the phase corresponding to the special value is determined as the target phase; A frequency offset is calculated using the target phase and the symbol interval of the target pilot symbol pair.

2. The frequency offset estimation method according to claim 1, characterized in that: After determining whether the target cross-correlation result is one of a plurality of preset special values, the method further includes: If the target cross-correlation result is not one of the preset multiple special values, then based on the conversion relationship between tangent and cotangent, calculate the tangent value according to the target cross-correlation result; Determining a first temporary phase according to the tangent value; Based on the conversion relationship between tangent and cotangent, and according to the first temporary phase, a second temporary phase is determined; The target phase is determined according to the second temporary phase and the sign bits of the real part and the imaginary part of the target cross-correlation result.

3. The frequency offset estimation method according to claim 2, characterized in that: Based on the conversion relationship between tangent and cotangent, the tangent value is calculated according to the target cross-correlation result, specifically including: When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, the tangent value is calculated using the following formula: tanA=Im(CorrValue) / Re(CorrValue) Wherein, tanA represents the tangent value, CorrValue represents the target cross-correlation result, Im() represents taking the imaginary part of the target cross-correlation result, and Re() represents taking the real part of the target cross-correlation result; When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus, the tangent value is calculated using the following formula: tanA=Re(CorrValue) / Im(CorrValue).

4. The frequency offset estimation method according to claim 3, characterized in that: Based on the conversion relationship between tangent and cotangent, determining the second temporary phase according to the first temporary phase specifically includes: When the real part modulus of the target cross-correlation result is greater than the imaginary part modulus thereof, the second temporary phase is obtained by calculating the difference between π / 2 and the first temporary phase; When the real part modulus of the target cross-correlation result is less than or equal to the imaginary part modulus thereof, it is determined that the second temporary phase is equal to the first temporary phase.

5. The frequency offset estimation method according to claim 2, characterized in that: Determining a first temporary phase according to the tangent value specifically includes: Determining whether the tangent value is less than or equal to a preset threshold; If the tangent value is less than or equal to a preset threshold, determining that the first temporary phase is equal to the tangent value; If the tangent value is greater than a preset threshold, the first temporary phase is determined by querying a preset tangent table.

6. The frequency offset estimation method according to claim 2, characterized in that: Determining the target phase according to the sign bits of the real part and the imaginary part of the second temporary phase and the target cross-correlation result specifically includes: When the real part and the imaginary part of the target cross-correlation result are both greater than 0, determining that the target phase is equal to the second temporary phase; When the real part of the target cross-correlation result is less than 0 and the imaginary part thereof is greater than 0, the target phase is obtained by calculating the difference between π and the second temporary phase; When the real part and the imaginary part of the target cross-correlation result are both less than 0, the target phase is obtained by calculating the difference between the second temporary phase and π; When the real part of the target cross-correlation result is greater than 0 and the imaginary part thereof is less than 0, the target phase is determined to be equal to the negative number of the second temporary phase.

7. The frequency offset estimation method according to claim 1, characterized in that: Based on all the cross-correlation results, a target cross-correlation result is obtained, which specifically includes: When the number of the cross-correlation results is 1, determining the cross-correlation result as the target cross-correlation result; When there are multiple cross-correlation results, the target cross-correlation result is obtained by taking an average value of all the cross-correlation results.

8. A frequency offset estimation device, characterized in that: include: An acquisition module, configured to acquire a pilot symbol set of a received signal, wherein the pilot symbol set includes a plurality of pilot symbols; A conjugate point multiplication module, used for performing conjugate point multiplication on the pilot symbol and the local pilot sequence to obtain a channel response estimation value corresponding to each pilot symbol; A first determination module is used to determine, for any symbol interval, all target pilot symbol pairs corresponding to the symbol interval, where the symbol interval is a symbol interval between two pilot symbols in the target pilot symbol pair; A conjugate multiplication module, configured to conjugate multiply the channel response estimation values ​​of the two pilot symbols in the target pilot symbol pair for each target pilot symbol pair, so as to obtain a cross-correlation result of the target pilot symbol pair; A first calculation module, configured to obtain a target cross-correlation result based on all the cross-correlation results; A judgment module, used for judging whether the target cross-correlation result is one of a plurality of preset special values; The special value is a value located on a coordinate axis of a two-dimensional Cartesian coordinate system; A second determination module is used to determine the phase corresponding to the special value as the target phase if the target cross-correlation result is one of a plurality of preset special values; The second calculation module is used to calculate the frequency offset using the target phase and the symbol interval of the target pilot symbol pair.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, each step in the frequency offset estimation method according to any one of claims 1 to 7 is implemented.

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