A frequency deviation estimation method, device and medium

Abstract

The present invention discloses a frequency offset estimation method, device and medium, the method comprising: obtaining a frequency domain received signal; determining a first symbol spacing and a second symbol spacing based on the frequency domain received signal, and correspondingly calculating and obtaining a first frequency offset estimation value and a second frequency offset estimation value; wherein the first symbol spacing is smaller than the second symbol spacing, and at least one of the first symbol spacing and the second symbol spacing is determined based on a reference signal symbol; for the first frequency offset estimation value and the second frequency offset estimation value, correspondingly obtaining a first real frequency offset value and a second real frequency offset value; determining a matching first real frequency offset value and a matching second real frequency offset value according to the intersection between the first frequency offset range and the second frequency offset range, and determining the final real frequency offset value therefrom; the first frequency offset range is the value range of the first real frequency offset value, and the second frequency offset range is the value range of the second real frequency offset value. The method provided by the present invention can obtain a frequency offset estimation value with a large frequency offset range and high accuracy.

Description

Technical Field

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

[0002] At present, when using DMRS signals to estimate Doppler shift, the frequency offset is usually estimated by using the phase difference between the channel estimation value estimated by the Additional DMRS symbol and the channel estimation value estimated by the preceding DMRS. When the interval between the two DMRS symbols used for frequency offset estimation is equal to 1, the estimated frequency offset range is the largest and the accuracy of the frequency offset estimation value is the lowest; as the interval value increases, the frequency offset range gradually decreases, while the accuracy of the frequency offset estimation value gradually increases.

[0003] It can be seen that there is a certain mutual exclusivity between the frequency offset range and the accuracy of the frequency offset estimation value, and how to estimate a larger frequency offset range while achieving higher frequency offset estimation accuracy is an urgent problem to be solved. Summary of the invention

[0004] The present invention provides a frequency offset estimation method, aiming to effectively solve the above technical problem.

[0005] According to a first aspect of the present invention, the present invention provides a frequency offset estimation method, comprising:

[0006] Acquire a frequency domain received signal, where the frequency domain received signal includes at least one reference signal symbol;

[0007] Determine a first symbol spacing and a second symbol spacing based on the frequency domain received signal, and correspondingly calculate to obtain a first frequency offset estimation value and a second frequency offset estimation value; wherein the first symbol spacing is smaller than the second symbol spacing, and at least one of the first symbol spacing and the second symbol spacing is determined based on the reference signal symbol;

[0008] Performing a phase flip on the first frequency offset estimation value according to the first symbol spacing, and at the same time, performing a phase flip on the second frequency offset estimation value according to the second symbol spacing, to correspondingly obtain a first true frequency offset value and a second true frequency offset value;

[0009] A matching first real frequency offset value and a matching second real frequency offset value are determined according to the intersection between the first frequency offset range and the second frequency offset range, and a final real frequency offset value is determined therefrom; the first frequency offset range is a value range of the first real frequency offset value, and the second frequency offset range is a value range of the second real frequency offset value.

[0010] According to a second aspect of the present invention, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of any one of the above methods.

[0011] According to a third aspect of the present invention, the present invention further provides a storage medium, wherein a plurality of instructions are stored in the storage medium, and the instructions are suitable for being loaded by a processor to execute the steps of any of the above methods.

[0012] Through one or more of the above-mentioned embodiments of the present invention, at least the following technical effects can be achieved: the first frequency offset estimation value and the second frequency offset estimation value are estimated by using the first symbol spacing and the second symbol spacing respectively, wherein the first symbol spacing is smaller than the second symbol spacing, so that the first frequency offset estimation value has a larger frequency offset range but lower estimation accuracy than the second frequency offset estimation value. Then, the first frequency offset estimation value and the second frequency offset estimation value are phase-flipped to obtain an estimation value closer to the actual situation, that is, the first real frequency offset value and the second real frequency offset value. The estimation value closest to the actual situation is determined by the intersection of the respective frequency offset ranges. The final real frequency offset value obtained by the method provided by the present invention has a higher accuracy and a larger frequency offset range. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The technical solutions and other beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0014] Figure 1 A flow chart of a frequency offset estimation method provided by an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of sub-steps of step S102 provided in an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of sub-steps of step S103 provided in an embodiment of the present invention;

[0017] Figure 4 One of the schematic diagrams of a frequency domain received signal provided by an embodiment of the present invention;

[0018] Figure 5 for Figure 4 Schematic diagram of signal symbols determined in;

[0019] Figure 6 The second schematic diagram of a frequency domain received signal provided by an embodiment of the present invention;

[0020] Figure 7 The third schematic diagram of a frequency domain received signal provided by an embodiment of the present invention;

[0021] Figure 8 for Figure 7 Schematic diagram of signal symbols determined in . DETAILED DESCRIPTION

[0022] The technical scheme in the embodiment of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein, unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship.

[0024] The coverage of low-orbit satellite communication services is larger than that of ground-based cellular network communications, and the satellites move faster, which results in more severe transmission delays and Doppler shifts in satellite communications. In order to solve the transmission delays and Doppler shifts caused by satellite communications, it is necessary to pre-process the transmission delay on the user side, pre-process the Doppler shift on the network side, and optimize and upgrade the algorithm.

[0025] To address the Doppler shift problem, the satellite can estimate the Doppler shift based on its speed and the elevation angle relative to the user, and pre-compensate the common Doppler shift on the network side. For the residual Doppler shift after pre-compensation, an optimized algorithm design is needed to overcome it.

[0026] In the Doppler shift estimation process, the commonly used frequency offset estimation method is to use the DMRS signal to perform Doppler shift estimation. Specifically, the frequency offset is calculated by using the phase difference between the channel estimation value estimated by the Additional DMRS symbol (additional reference signal symbol used for data demodulation in the LTE (Long-Term Evolution) system) and the channel estimation value estimated by the pre-DMRS. The calculation formula is as follows:

[0027] ;

[0028] Among them, FO (Frequency Offset) is the frequency offset estimation value, PO (Phase Offset) is the phase offset, Indicates the number of symbols used to estimate the interval between two symbols when estimating FO. Indicates the duration of an OFDM symbol (i.e., a symbol in orthogonal frequency division multiplexing), which is a fixed value in a specific system.

[0029] In addition, since frequency offset will cause phase rotation, the phase is 2π periodic, that is, the estimated phase offset caused by frequency offset is between [-π,π], and then the estimated phase offset PO range is , that is, the estimated frequency deviation range is , that is:

[0030] .

[0031] From the above, it can be seen that when the number of symbols between the two symbols of the estimated FO is equal to 1, the range of FO is the largest, but the estimated FO accuracy is the lowest. In general, the accuracy of FO estimation is proportional to the number of symbols in the interval, and the range of FO is inversely proportional to the number of symbols. As the number of symbols increases, the estimated FO accuracy gradually increases, while the range of FO becomes smaller. Schematically, in NR PUSCH, the minimum number of symbols in the DMRS symbol interval is 2. In the scenario where the subcarrier spacing is 30khz, the maximum estimable Doppler frequency shift is 7007hz, which is not enough to cover the maximum frequency deviation that may occur in the NTN scenario. Therefore, how to ensure the estimation accuracy of FO and obtain a larger FO estimation range in the scenario with a large Doppler frequency offset is an urgent problem to be solved.

[0032] Before describing the frequency offset estimation method, device, and medium provided by the embodiments of the present invention in conjunction with the accompanying drawings, the terms involved in the present invention are first described.

[0033] NTN stands for Non-Terrestrial Networks, which refers to non-terrestrial network communications, not only satellite communications (Spaceborne), but also airships, drones (Airborne), etc. Among them, satellite communications account for the largest proportion. Satellites are classified according to their altitude, and can be divided into synchronous satellites (GEO: Geostationary Earth Orbit satellite) with an altitude of 35786km; medium-orbit satellites (MEO: Medium Earth Orbit satellite) with an altitude of 7000~25000km; low-orbit satellites (LEO: Low Earth Orbit satellite) with an altitude of 300~1500km.

[0034] Compared with ground-based cellular communication technology, low-orbit satellite communication technology has significantly enhanced service coverage capabilities and can cover extreme areas such as deserts, forests and oceans. In addition, low-orbit satellite communication has greater robustness and flexibility in responding to natural disasters or physical attacks. Therefore, low-orbit satellite communication has broad application prospects in transportation, public safety, e-health, agriculture, finance, automobiles and other fields.

[0035] DMRS (Demodulation Reference Signal) is a reference signal used to implement carrier frequency offset estimation in 5G systems. It carries additional information on the physical layer to help the receiver estimate the frequency offset of the channel. DMRS symbols are usually located in special positions of OFDM (Orthogonal Frequency Division Multiplexing) symbols, such as specific symbol positions in PUSCH (Physical Uplink Shared Channel) or PUCCH (Physical Uplink Control Channel) symbols. These symbols are arranged throughout the transmission frame to provide the reference signal required for frequency offset estimation.

[0036] PUSCH (Physical Uplink Shared Channel) is a physical uplink shared channel, which mainly carries user data and uplink control information (UCI).

[0037] PUCCH (Physical Uplink Control Channel) is a physical uplink control channel used to transmit control information such as HARQ ACK / NACK, scheduling request (SR), channel state information (CSI), etc.

[0038] Figure 1 A flow chart of a frequency offset estimation method provided by an embodiment of the present invention, such as Figure 1 As shown, a frequency offset estimation method comprises the following steps:

[0039] S101: Acquire a frequency domain received signal, where the frequency domain received signal includes at least one reference signal symbol.

[0040] The network side receives the time domain signal sent by the user side and converts it into a frequency domain signal. The frequency domain signal includes a data symbol and a reference signal symbol DMRS symbol. The reference signal DMRS can be used for channel estimation, scheduling, demodulation and frequency offset estimation.

[0041] S102, determining a first symbol spacing and a second symbol spacing based on the frequency domain received signal, and correspondingly calculating and obtaining a first frequency offset estimation value and a second frequency offset estimation value. That is, the first frequency offset estimation value is calculated according to the first symbol spacing, and the second frequency offset estimation value is calculated according to the second symbol spacing.

[0042] The first symbol spacing is smaller than the second symbol spacing, and at least one of the first symbol spacing and the second symbol spacing is determined based on the reference signal symbol.

[0043] The first symbol spacing is the number of symbols spaced between Symbol A and Symbol B in the frequency domain received signal, and the second symbol spacing is the number of symbols spaced between Symbol C and Symbol D. Symbol A, Symbol B, Symbol C, and Symbol D may all be different, or two of them may be the same. At least one of Symbol A, Symbol B, Symbol C, and Symbol D is a reference signal symbol DMRS symbol.

[0044] In the case where the frequency domain received signal contains multiple reference signal symbols, the reference signal symbol DMRSsymbol is preferentially used to calculate the first symbol spacing and the second symbol spacing. In the case where the frequency domain received signal contains 1 or 2 reference signal symbols, the digital symbol Data symbol and the reference signal symbol DMRS symbol are required to calculate the first symbol spacing and the second symbol spacing. That is to say, when the number of DMRS symbols is small, some of Symbol A, Symbol B, Symbol C and Symbol D can be Data symbols; when the number of DMRS symbols is large, Symbol A, Symbol B, Symbol C and Symbol D are all DMRS symbols.

[0045] The accuracy of FO estimation is proportional to the spacing, while the range of FO is inversely proportional to the spacing. Therefore, when the first symbol spacing is smaller than the second symbol spacing, the accuracy of the first frequency offset estimation value FO1 is smaller than the accuracy of the second frequency offset estimation value FO2, while the frequency offset range of the first frequency offset estimation value FO1 is larger than the frequency offset range of the second frequency offset estimation value FO2.

[0046] S103, performing a phase flip on the first frequency offset estimation value according to the first symbol spacing, and at the same time, performing a phase flip on the second frequency offset estimation value according to the second symbol spacing, to correspondingly obtain at least one first true frequency offset value and a second true frequency offset value.

[0047] In this step, the number of phase flips is determined according to the first symbol spacing and the second symbol spacing, respectively, and the phase of the first frequency offset estimate and the second frequency offset estimate is flipped using the respective number of phase flips, thereby obtaining at least one possible first true frequency offset value and at least one possible second true frequency offset value.

[0048] S104: Determine a matching first real frequency offset value and a matching second real frequency offset value according to an intersection between the first frequency offset range and the second frequency offset range, and determine a final real frequency offset value therefrom.

[0049] The first frequency offset range is a value range of the first real frequency offset value, and the second frequency offset range is a value range of the second real frequency offset value.

[0050] When there is an intersection between the first frequency deviation range and the second frequency deviation range, it can be considered that the related first real frequency deviation value is relatively close to the second real frequency deviation value, and the two are confirmed to be matching first real frequency deviation values ​​and matching second real frequency deviation values. It should be noted that since there may be multiple first real frequency deviation values ​​and second real frequency deviation values, there may be multiple corresponding first frequency deviation ranges and second frequency deviation ranges, and thus there may be multiple groups of matching first real frequency deviation values ​​and matching second real frequency deviation values. The final real frequency deviation value is determined from at least one group of matching first real frequency deviation values ​​and matching second real frequency deviation values.

[0051] That is, a matching first real frequency offset value and a matching second real frequency offset value are determined according to the intersection of the first frequency offset range and the second frequency offset range, and an optimal frequency offset value is selected therefrom.

[0052] The frequency offset estimation method provided by the embodiment of the present invention uses the first symbol spacing and the second symbol spacing respectively to estimate the first frequency offset estimation value and the second frequency offset estimation value, wherein the first symbol spacing is smaller than the second symbol spacing, so that the first frequency offset estimation value has a larger frequency offset range but lower estimation accuracy than the second frequency offset estimation value. Then, the first frequency offset estimation value and the second frequency offset estimation value are phase-flipped to obtain an estimation value closer to the actual situation, that is, the first real frequency offset value and the second real frequency offset value. The estimation value closest to the actual situation is determined by the intersection of the respective frequency offset ranges. The final real frequency offset value obtained by the method provided by the present invention has a higher accuracy and a larger frequency offset range.

[0053] In some embodiments of the present invention, the first symbol spacing is the spacing between the first signal symbol and the second signal symbol, the second symbol spacing is the spacing between the second signal symbol and the third signal symbol, and at least one of the first signal symbol, the second signal symbol and the third signal symbol is a reference signal symbol.

[0054] That is to say, three of the multiple signal symbols included in the frequency domain received signal are determined to be used for calculating the first symbol spacing and the second symbol spacing. Specifically, at least one of the first signal symbol, the second signal symbol, and the third signal symbol is a reference signal symbol DMRS symbol, and the remaining two can be Data symbols when the number of DMRS symbols included in the frequency domain received signal is small, and are both DMRS symbols when the number is large. Compared with Datasymbol, DMRS symbol is preferentially used to calculate the first symbol spacing and the second symbol spacing.

[0055] It should be noted that the first signal symbol, the second signal symbol and the third signal symbol here do not refer to the position of the signal symbols in the data sequence of the frequency domain received signal. The second signal symbol may be before the first signal symbol or after the third signal symbol. The third signal symbol may also be before the first signal symbol. There is no limitation on this.

[0056] The frequency offset estimation method provided in the embodiment of the present invention is applicable to the method that requires at least 2 DMRS symbols for spacing calculation. The present invention can also be applied to the case where there is only 1 DMRS symbol, and has a wider range of adaptability.

[0057] In some embodiments of the present invention, the method further comprises:

[0058] Based on the goal of minimizing the first symbol spacing and maximizing the second symbol spacing, a first signal symbol, a second signal symbol and a third signal symbol are determined from each signal symbol of the frequency domain received signal.

[0059] The first signal symbol is a reference signal symbol, and the frequency domain received signal is actually a group of data sequences. Each signal symbol has a corresponding position number in the data sequence, and the spacing between each signal symbol can be determined based on the position number.

[0060] The following is a specific description of signal symbol determination for situations where the frequency domain received signal includes one reference signal symbol, two reference signal symbols, three reference signal symbols, or more.

[0061] In the case where there is only one reference signal symbol in the frequency domain received signal, the first signal symbol is determined. At this time, based on the goal of minimizing the spacing between the first symbols, the data symbols on both sides of the first signal symbol are used as two candidate second signal symbols. Based on the goal of maximizing the spacing between the second symbols, the front and back signal symbols in the frequency domain received signal are first used as two candidate third signal symbols, and the spacing between the two candidate second signal symbols and the two candidate third signal symbols is compared, and the group with the largest spacing is determined as the second signal symbol and the third signal symbol. It should be noted that if the first signal symbol is at the front or the back, there is only one determined second signal symbol, and then there is only one determined third signal symbol. In addition, if multiple spacings are simultaneously the largest during the spacing comparison process, a group of candidate second signal symbols and candidate third signal symbols can be randomly determined as the final second signal symbol and third signal symbol.

[0062] In some embodiments, only one reference signal symbol appears in the second half of the frequency domain received signal. At this time, based on the principle that the first symbol spacing is the smallest and the second symbol spacing is the largest, the last data symbol of the frequency domain received signal is determined as the third signal symbol, and the data symbol before the reference signal symbol is determined as the second signal symbol. In other embodiments, only one reference signal symbol appears in the first half of the frequency domain received signal. At this time, based on the principle that the first symbol spacing is the smallest and the second symbol spacing is the largest, the first data symbol of the frequency domain received signal is determined as the third signal symbol, and the data symbol after the reference signal symbol is determined as the second signal symbol.

[0063] Schematically, the frequency domain received signal includes 4 signal symbols as shown in Table 1, wherein the DMRS symbol at position 2 is the first signal symbol. When the first signal symbol is clear, the Data symbol at position 1 and the Data symbol at position 3 adjacent to the first signal symbol both comply with the principle of minimum spacing of the first symbol. However, in order to maximize the spacing of the second symbol, the Data symbol at position 1 is used as the second signal symbol, and the Data symbol at position 4 is used as the third signal symbol. At this time, the first symbol spacing is the spacing between position 1 and position 2, and the value is 1; the second symbol spacing is the spacing between position 4 and position 1, and the value is 3.

[0064] Table 1 Schematic diagram of frequency domain received signal with only one DMRS symbol

[0065]

[0066] In the case where the frequency domain received signal includes two reference signal symbols, the first signal symbol is one of the two reference signal symbols. In addition, considering that the two reference signal symbols are not adjacent in actual situations and in order to meet the goal of minimizing the first symbol spacing, the remaining reference signal symbol is the third signal symbol. Which of the two reference signal symbols the first signal symbol is specifically can be determined by the following method:

[0067] First, two reference signal symbols S1 and S2 are used as candidate first signal symbols and candidate third signal symbols, where one group of candidate first signal symbols is S1 and the candidate third signal symbol is S2; the other group of candidate first signal symbols is S2 and the candidate third signal symbol is S1.

[0068] Then, the data symbols adjacent to the candidate first signal symbols S1 and S2 are respectively taken as candidate second signal symbols S1-, S1+, S2- and S2+.

[0069] Then, compare the spacing between the candidate second signal symbols and the candidate third signal symbols, specifically compare the spacing between S1- and S2, S1+ and S2, S2- and S1, S2+ and S1, determine the second signal symbol and the third signal symbol based on the group with the largest spacing value, and then determine the first signal symbol.

[0070] It should be noted that, when the candidate first signal symbols S1 and S2 are the front end or the rear end of the frequency domain received signal, the number of candidate second signal symbols will change accordingly.

[0071] In addition, in the interval comparison, if all are the largest, one group can be determined as the final second signal symbol and the final third signal symbol from any one of the multiple groups of candidate second signal symbols and candidate third signal symbols.

[0072] In addition, in actual situations, the reference signal symbol with a forward position among the two reference signal symbols S1 and S2 can be directly used as the first signal symbol, and the remaining reference signal symbol can be determined as the third signal symbol based on the determined first signal symbol, and the second signal symbol can be further determined based on the goal of minimizing the first symbol spacing and maximizing the second symbol spacing.

[0073] Indicatively, the frequency domain received signal includes 5 signal symbols as shown in Table 2, wherein the front one of the DMRS symbol at position 2 and the DMRS symbol at position 4 is used as the first signal symbol, and the other is used as the third signal symbol, and the Data symbol at position 1 is determined as the second signal symbol based on the principle of the smallest spacing with the first signal symbol and the largest spacing with the third signal symbol. At this time, the first symbol spacing is the spacing between position 1 and position 2, and the value is 1; the second symbol spacing is the spacing between position 1 and position 4, and the value is 3.

[0074] Table 2 Schematic diagram of frequency domain received signal with only two DMRS symbols

[0075]

[0076] When the frequency domain received signal includes at least three reference signal symbols, a candidate second signal symbol and a candidate third signal symbol are determined from the at least three reference signal symbols according to a goal of maximizing the second symbol spacing.

[0077] According to the goal of minimizing the first symbol spacing, the reference signal symbol adjacent to the candidate second signal symbol is used as the first signal symbol, and then the final second signal symbol and the final third signal symbol are determined from the candidate second signal symbols and the candidate third signal symbols.

[0078] In this embodiment, based on the principle of making full use of reference signal symbols to calculate the first symbol spacing and the second symbol spacing, when the frequency domain received signal includes at least three reference signal symbols, the first signal symbol, the second signal symbol, and the third signal symbol are all reference signal symbols, and which one of the at least three reference signal symbols they specifically correspond to can be determined in the following manner:

[0079] Based on the principle of the largest second symbol spacing, the two reference signal symbols RS-S and RS-L that are farthest apart are determined as candidate second signal symbols and third signal symbols. At this time, there may be two situations. One is that RS-S is a candidate second signal symbol and RS-L is a candidate third signal symbol, and the other is that RS-L is a candidate second signal symbol and RS-S is a candidate third signal symbol.

[0080] Then, the reference signal symbol RS-M adjacent to the candidate second signal symbol is used as the candidate first signal symbol. RS-M can be adjacent to RS-S or RS-L. When there are only three reference signal symbols, there is only one RS-M; when there are more than three reference signal symbols, there can be two RS-Ms.

[0081] Furthermore, based on the goal of minimizing the first symbol spacing, a group is determined from the candidate first signal symbols and the candidate second signal symbols as the final first signal symbol and the second signal symbol, and then the final third signal symbol is determined.

[0082] Table 3 Schematic diagram of frequency domain received signals with only three DMRS symbols

[0083]

[0084] Schematically, the frequency domain received signal includes 7 signal symbols as shown in Table 3, among which, since the DMRS symbol at position 2 and the DMRS symbol at position 7 are the farthest apart, the DMRS symbol at position 2 and the DMRS symbol at position 7 are locked as the second signal symbol and the third signal symbol. At this time, the DMRS symbol at position 2 may be the second signal symbol or the third signal symbol.

[0085] Then, based on the determined first symbol signal and the principle of the minimum spacing between the first symbols (that is, the minimum spacing between the first signal symbol and the second signal symbol), it is determined whether the DMRS symbol at position 2 is the second signal symbol or the third signal symbol. Specifically, since the DMRS symbol at position 5 is both the reference signal symbol adjacent to position 2 and the reference signal symbol adjacent to position 7. Therefore, the DMRS symbol at position 5 is directly determined to be the third signal symbol. Subsequently, since the spacing between the DMRS symbol at position 5 and the DMRS symbol at position 2 is 3, and the spacing between the DMRS symbol at position 7 is 2, the DMRS symbol at position 7 is the second signal symbol, and the DMRS symbol at position 2 is the third signal symbol. At this time, the first symbol spacing is the spacing between position 5 and position 7, and the value is 2; the second symbol spacing is the spacing between position 2 and position 7, and the value is 5.

[0086] Table 4 Schematic diagram of frequency domain received signals with only four DMRS symbols

[0087]

[0088] For another example, the frequency domain received signal includes 10 signal symbols as shown in Table 4, wherein, since the DMRS symbol at position 1 and the DMRS symbol at position 10 are the farthest apart, the DMRS symbol at position 1 and the DMRS symbol at position 10 are locked as the second signal symbol and the third signal symbol. At this time, the DMRS symbol at position 1 may be the second signal symbol or the third signal symbol.

[0089] Then, based on the principle of the minimum first symbol spacing, determine whether the DMRS symbol at position 2 is the second signal symbol or the third signal symbol. Specifically, the DMRS symbol at position 5, which is adjacent to position 2, and the DMRS symbol at position 7, which is adjacent to position 10, are first selected as candidate first signal symbols. Since the interval between position 5 and position 1 is 4, and the interval between position 7 and position 10 is 3, the DMRS symbol at position 10 is determined as the second signal symbol, the DMRS symbol at position 7 is determined as the first signal symbol, and the DMRS symbol at position 1 is determined as the third signal symbol. At this time, the first symbol spacing is the interval between position 7 and position 10, which is 3; the second symbol spacing is the interval between position 1 and position 10, which is 9.

[0090] It should be noted that, in actual situations, the frequency domain received signal includes at most 4 DMRS symbols.

[0091] The first signal symbol, second signal symbol and third signal symbol determined in the above manner can obtain the minimum first symbol spacing and the maximum second symbol spacing, and the corresponding first frequency offset estimation value is the one with the largest frequency offset range but the lowest accuracy, while the second frequency offset estimation value is the one with the smallest frequency offset range but the highest accuracy.

[0092] In some embodiments of the present invention, Figure 2 As shown, S102 includes the following sub-steps:

[0093] S1021, respectively estimate the phase offset of the first signal symbol, the second signal symbol, and the third signal symbol to obtain a first phase offset, a second phase offset, and a third phase offset accordingly.

[0094] In this step, phase offset estimation is performed on the three signal symbols respectively to obtain a first phase offset corresponding to the first signal symbol, a second phase offset corresponding to the second signal symbol, and a third phase offset corresponding to the third signal symbol.

[0095] Among them, the phase offset estimation can be performed using a preset phase offset estimation algorithm, which may be a phase offset estimation algorithm based on a constellation diagram, a phase offset estimation algorithm based on a channel estimation value, a phase offset estimation algorithm based on a pilot, a maximum likelihood estimation method, a phase offset estimation algorithm based on machine learning, a phase offset estimation algorithm based on the statistical characteristics of a signal, etc., without limitation.

[0096] S1022: Calculate the first frequency offset estimate value based on the first symbol spacing, the phase difference between the first phase offset and the second phase offset, and simultaneously, calculate the second frequency offset estimate value based on the second symbol spacing, the phase difference between the second phase offset and the third phase offset.

[0097] In some embodiments of the present invention, S1021 includes the following sub-steps:

[0098] S201, when the frequency domain received signal includes one reference signal symbol or two reference signal symbols, use an equalizer to process the first signal symbol, the second signal symbol and the third signal symbol respectively and map them to a preset constellation diagram to obtain corresponding equalized constellation points.

[0099] S202: Calculate a first phase offset, a second phase offset, and a third phase offset according to the equalized constellation point and the standard constellation point corresponding to the constellation diagram.

[0100] That is to say, when the number of reference signal symbols in the frequency domain received signal is less than 3, the phase offset estimation algorithm based on the constellation diagram is used to perform phase offset estimation. Specifically, the equalizer is used to perform equalization processing on the first signal symbol Symbol 1, the second signal symbol Symbol 2, and the third signal symbol Symbol 3 respectively and map them to the preset constellation diagram to obtain the corresponding equalized constellation point , , Then, the standard constellation point corresponding to the equalized constellation point is obtained on the constellation diagram. , , .

[0101] Then, the corresponding first phase offset PO11, second phase offset PO21 and third phase offset PO31 are calculated according to the first phase offset calculation formula:

[0102]

[0103] In the formula, Indicates the signal symbol ( , M represents the total number of signal symbols on the constellation points) equalized constellation points; Indicates The standard constellation point corresponding to the equalized constellation point; It means sum; Indicates the angle.

[0104] The frequency offset estimation method provided by the embodiment of the present invention completes the phase offset estimation by using a phase offset estimation algorithm based on a constellation diagram when the number of reference signal symbols is less than 3.

[0105] In some embodiments of the present invention, S1021 includes the following sub-steps:

[0106] S301, when the frequency domain received signal includes at least three reference signal symbols, channel estimation is performed on the first signal symbol, the second signal symbol and the third signal symbol respectively, and a first channel estimation value H1, a second channel estimation value H2 and a third channel estimation value H3 are correspondingly obtained.

[0107] S302: Calculate a first phase offset PO1 according to the first channel estimation value and the second channel estimation value.

[0108] S303: Calculate and obtain a second phase offset PO2 according to the first channel estimation value and the third channel estimation value.

[0109] S304: Calculate and obtain a third phase offset PO3 according to the second channel estimation value and the third channel estimation value.

[0110] That is to say, when the number of reference signal symbols included in the frequency domain received signal is greater than or equal to 3, the phase offset estimation algorithm based on the channel estimation value is used to perform the phase offset estimation.

[0111] Specifically, the channel estimation values ​​H1, H2, and H3 of the first signal symbol, the second signal symbol, and the third signal symbol are calculated respectively; then the corresponding first phase offset PO12, the second phase offset PO22, and the third phase offset PO32 are calculated respectively by the following second phase offset calculation formula:

[0112]

[0113] in, For the ( 2, M2 represents the total number of constellation points on the second signal symbol) of the second channel estimation value; Indicates the first signal symbol the conjugate of the first channel estimate; It means sum; Indicates the angle.

[0114]

[0115] in, For the ( 1, M1 represents the total number of constellation points on the first signal symbol) of the first channel estimation value; Indicates the third signal symbol the conjugate of a third channel estimate; It means sum; Indicates the angle.

[0116]

[0117] in, For the ( 2, M2 represents the total number of constellation points on the second signal symbol) of the second channel estimation value; Indicates the third signal symbol the conjugate of a third channel estimate; It means sum; Indicates the angle.

[0118] It should be noted that there is no fixed order among the above S302, S203, and S304, and they can be executed simultaneously, which is not limited in the present invention.

[0119] The frequency offset estimation method provided by the embodiment of the present invention, when the number of reference signal symbols contained in the frequency domain received signal is greater than or equal to 3, uses a phase offset estimation algorithm based on channel estimation values ​​to complete phase offset estimation, thereby achieving an anti-interference effect.

[0120] In some embodiments of the present invention, Figure 3 As shown, the S103 includes the following sub-steps:

[0121] S1031, determine the corresponding first flip number set and second flip number set according to the first symbol spacing and the second symbol spacing, respectively. That is, determine the possible value range of the flip number of the first frequency offset estimation value (i.e., the first flip number) according to the first symbol spacing, and obtain at least one first flip number within the range to form the first flip number set. Similarly, determine the possible value range of the flip number of the second frequency offset estimation value (i.e., the second flip number) according to the second symbol spacing, and obtain at least one second flip number within the range to form the second flip number set.

[0122] S1032: Perform phase flipping on the first frequency offset estimation value using each first flipping number in the first flipping number set to obtain a first real frequency offset value set.

[0123] In this step, the first frequency offset estimation value is phase-flipped multiple times by different first flipping times to obtain at least one first real frequency offset value to form a first real frequency offset value set.

[0124] S1033: Perform phase flipping on the second frequency offset estimation value using each second flipping number in the second flipping number set to obtain a second real frequency offset value set.

[0125] Similarly, the second frequency offset estimation value is subjected to multiple phase flips with different second flipping times to obtain at least one second real frequency offset value to form a second real frequency offset value set.

[0126] It should be noted that there is no order between S1032 and S1033 and they can be executed simultaneously, and the present invention does not limit this.

[0127] The frequency offset estimation method provided by the embodiment of the present invention obtains all possible first true frequency offset value sets and second true frequency offset value sets by traversing all possible flipping times, thereby improving the accuracy and range of frequency offset estimation.

[0128] In some embodiments of the present invention, S1031 includes the following sub-steps:

[0129] S401, determining a first number value range and a second number value range according to a first symbol spacing n1 and a second symbol spacing n2 respectively.

[0130] S402: Select all values ​​from the first number value range and the second number value range respectively to obtain a first flip number set and a second flip number set respectively.

[0131] The first number of times is within the range of the absolute value of the first flip number W1a being less than The second number of times is within the range of the absolute value of the second flip number W2b being less than , the first flipping number W1a and the second flipping number W2b are integers. That is, the first flipping number has a value range of: <W1a< , the second number value range: <W2b< .

[0132] In schematic form, if n1=1, the value range of W1a is (-1, 1), and the first flip number set W1={0} is obtained by taking all values ​​in the range, and W1a is the ath first flip number in W1. If n2=3, the value range of W2b is (-2, 2), and the second flip number set W2={-1, 0, 1} is obtained by taking all values ​​in the range, and W2b is the bth second flip number in W2.

[0133] Subsequently, the first frequency offset estimation value is phase-flipped according to the first flip number in the first flip number set W1, and a plurality of first real frequency offset values ​​are obtained to form a first real frequency offset value set. Similarly, the second frequency offset estimation value is phase-flipped according to the second flip number in the second flip number set W2, and a plurality of second real frequency offset values ​​are obtained to form a second real frequency offset value set.

[0134] Among them, the first true frequency deviation value , is the duration of an OFDM symbol, is the first frequency offset estimate, and accordingly, the first real frequency offset value The frequency deviation range is .

[0135] The second true frequency deviation value , accordingly, the second true frequency deviation value The frequency deviation range is .

[0136] The frequency offset estimation method provided in an embodiment of the present invention determines the first number value range and the second number value range for the first frequency offset estimate value and the second frequency offset estimate value respectively through the first symbol spacing and the second symbol spacing, and obtains all the flipping times within the number value range, and then the first frequency offset estimate value and the second frequency offset estimate value are phase-flipped according to all the flipping times, so as to obtain as many first true frequency offset values ​​and second true frequency offset values ​​as possible, thereby improving the frequency offset estimation accuracy.

[0137] In some embodiments of the present invention, S104 includes the following sub-steps:

[0138] S1041 matching step, randomly select a first frequency offset range from the first frequency offset range set as the current first frequency offset range, compare it with each second frequency offset range in the second frequency offset range set, and select the second frequency offset range with an intersection as the second frequency offset range that matches the current first frequency offset range, and select the first real frequency offset value corresponding to the current first frequency offset range as the matched first real frequency offset value, and the second real frequency offset value corresponding to the matched second frequency offset range as the matched second real frequency offset value.

[0139] Schematically, if the first real frequency deviation value set F1 is {F10} and the second real frequency deviation value set F2 is {F20, F21, F22}, the frequency deviation range of F10 is taken as the current first frequency deviation range, and is compared with the frequency deviation ranges of F20, F21, and F22 respectively; if the frequency deviation ranges of F21, F22 and F10 intersect, F10 and F21 are taken as a set of matching first real frequency deviation values ​​and matching second real frequency deviation values, and F10 and F22 are taken as another set of matching first real frequency deviation values ​​and matching second real frequency deviation values.

[0140] In step S1042, the matching step S1041 is repeatedly performed until all the first frequency offset ranges in the first frequency offset range set are exhausted, so as to obtain at least one set of matched first real frequency offset values ​​and matched second real frequency offset values.

[0141] Schematically, if the first real frequency deviation value set F1 is {F10, F11}, and the second real frequency deviation value set F2 is {F20, F21, F22}, a frequency deviation range of the first real frequency deviation value is randomly selected from F1 as the current first frequency deviation range, which can be F10 or F11. Taking F10 as an example, it is assumed that the matching real frequency deviation values ​​obtained by executing the matching step are still F10 and F21, F10 and F22. Further, the frequency deviation range of F11 is used as the current first frequency deviation range, and then compared with the frequency deviation ranges of each second real frequency deviation value in F2. It is assumed that the matching real frequency deviation values ​​obtained at this time are F11 and F22. After terminating the loop, 3 groups of matching real frequency deviation values ​​F10 and F21, F10 and F22, and F11 and F22 are finally obtained.

[0142] In other embodiments of the present invention, the second frequency offset range set may be used as the basis, and intersection matching may be performed for each current second frequency offset range from the first frequency offset range set, so as to finally obtain multiple groups of matched real frequency offset values. The specific matching process is the same as above and will not be repeated here.

[0143] In some embodiments of the present invention, S104 further includes the following sub-steps:

[0144] S1043: Calculate an error between the matched first real frequency offset value and the matched second real frequency offset value to obtain a plurality of error values.

[0145] Taking the above three groups of matched real frequency offset values ​​F10 and F21, F10 and F22, and F11 and F22 as examples, the errors between F10 and F21, F10 and F22, and F11 and F22 are calculated respectively, thereby obtaining three error values.

[0146] The error value may be an absolute error, a relative error, a square error, etc. between two real frequency offset values. Preferably, in this embodiment, the error value is an absolute error.

[0147] S1044: Determine a target first real frequency offset value and a target second real frequency offset value from a plurality of matched sets of first real frequency offset values ​​and second real frequency offset values ​​according to the error value, and use the target second real frequency offset value as a final real frequency offset value.

[0148] In this step, the set of matched real frequency offset values ​​with the smallest error value is used as the target real frequency offset value.

[0149] The frequency offset estimation method provided by the embodiment of the present invention determines the target true frequency offset value according to the error value, and the frequency offset range corresponding to the target true frequency offset value is larger and has higher precision. Furthermore, based on the fact that the second frequency offset estimate value has higher precision than the first frequency offset estimate value, correspondingly, the second true frequency offset value has higher precision than the first true frequency offset value, and therefore, the target second true frequency offset value in the target true frequency offset value is used as the final true frequency offset value, thereby further improving the precision of the final true frequency offset value. Therefore, the final true frequency offset value has both higher precision and a larger frequency offset range.

[0150] In some embodiments of the present invention, a frequency offset estimation method is described in detail by taking an example where a frequency domain received signal only includes two reference signal symbols DMRSsymbol.

[0151] like Figure 4 As shown, the frequency domain received signal is a PUSCH data sequence with 14 symbols, and in other embodiments, it can also be data in other uplink channels such as PUCCH. The signal symbols at positions 2 and 11 in the PUSCH data sequence are DMRS symbols, and the remaining positions are all Data symbols. On this basis, the frequency offset estimation method includes the following steps:

[0152] S11, based on the goal of minimizing the first symbol spacing and maximizing the second symbol spacing, determine that the DMRS symbol at position 2 is the first signal symbol, the Data symbol at position 1 is the second signal symbol, and the DMRS symbol at position 11 is the third signal symbol, such as Figure 5 At this time, the first symbol spacing n11 is the spacing between position 1 and position 2, n11=1, and the second symbol spacing n21 is the spacing between position 1 and position 11, n21=10.

[0153] The specific process of determining the first signal symbol, the second signal symbol and the third signal symbol refers to the case where the frequency domain received signal includes two reference signal symbols, which will not be repeated here.

[0154] S12, respectively calculating the constellation diagrams after equalization of the first signal symbol, the second signal symbol and the third signal symbol , , and standard constellation diagram , , , and then use the equalized constellation diagram and the standard constellation diagram to calculate the corresponding PO11, PO21, and PO31 through the following first phase offset calculation formula:

[0155] .

[0156] Then, according to the first symbol spacing n11=1, the phase difference between PO11 and PO21, FO1 is calculated by the following formula:

[0157] .

[0158] According to the second symbol spacing n21=10, the phase difference between PO21 and PO31, FO2 is calculated by the following formula:

[0159] .

[0160] S13, for FO1, due to <W1a< And n11=1, a first flip number set W1{w10=0} is obtained. According to the first flip number set W1, the first frequency offset estimate value FO1 is phase flipped using the following calculation formula to obtain a first true frequency offset value set F1{F10=FO1}:

[0161] .

[0162] Similarly, for FO2, due to <W2b< And n21=10, the second flip number set W2{0,1,-1,2,-2,3,-3,4,-4,5,-5} is obtained. According to the second flip number set W2, the second frequency offset estimate value FO2 is phase flipped using the following calculation formula to obtain the second real frequency offset value set F2:

[0163] .

[0164] The second real frequency offset value set is specifically: F2{F20=FO2, F21=FO2+ , F22=FO2- , F23=FO2+ , F24=FO2- , F25=FO2+ , F26=FO2- , F27=FO2+ , F28=FO2- , F29=FO2+ , F210=FO2- .

[0165] S14, for the first real frequency offset value set F1, calculate the possible value range of each first real frequency offset value in the F1 set, so as to obtain a first frequency offset range .

[0166] Similarly, for the second real frequency offset value set F2, the possible value range of each second real frequency offset value in the set F2 is calculated, so as to obtain each second frequency offset range F20: ; F21: ; F22: ; F23: ; F24: ; F25: ; F26: ; F27: ; F28: ; F29: ; F210: .

[0167] S15, compare the first frequency offset range with each second frequency offset range, determine the combination of the ranges with an intersection, and calculate the difference F3c between the corresponding first real frequency offset value and the second real frequency offset value, so as to obtain a difference set F3. Schematically, if there is an intersection between the frequency offset ranges of F10 and F20, then calculate F30=F10-F20, and add F30 to the F3 set. Repeat the above process until F10 is compared with all the second true frequency deviation values ​​in set F2, thereby finally obtaining set F3 {F30=F10-F20, F31=F10-F21, F32=F10-F22, F33=F10-F23, F34=F10-F24, F35=F10-F25, F36=F10-F26, F37=F10-F27, F38=F10-F28, F39=F10-F29, F310=F10-F210}.

[0168] S16, take the difference with the smallest absolute value in the set F3 as F3z, where F3z=F1j-F2k, that is, the first real frequency offset value corresponding to F3z is F1j (that is, the target first real frequency offset value), the first flip number is w1j, the second real frequency offset value is F2k (that is, the target second real frequency offset value), and the second flip number is w2k. Finally, considering that the second symbol spacing n21 is greater than the first symbol spacing n11, in order to estimate the FO with higher accuracy, F2k is used as the final real frequency offset value.

[0169] The frequency offset estimation method provided by the embodiment of the present invention can obtain a frequency offset value with a larger frequency offset range and higher accuracy in the case where there are only two reference signal symbols.

[0170] In some embodiments of the present invention, a frequency offset estimation method is described in detail by taking an example where a frequency domain received signal only includes three reference signal symbols DMRSsymbol.

[0171] like Figure 6 As shown, the frequency domain received signal is a PUSCH data sequence with 12 symbols. The signal symbols at positions 2, 6 and 9 in the PUSCH data sequence are DMRS symbols, and the remaining positions are all Data symbols. On this basis, the frequency offset estimation method includes the following steps:

[0172] S21, based on the goal of minimum first symbol spacing and maximum second symbol spacing, determine that the DMRS symbol at position 6 is the first signal symbol, the DMRS symbol at position 9 is the second signal symbol, and the DMRS symbol at position 2 is the third signal symbol. At this time, the first symbol spacing n12 is the spacing between position 6 and position 9, n12=3, and the second symbol spacing n22 is the spacing between position 2 and position 9, n22=7.

[0173] The specific determination process of the first signal symbol, the second signal symbol and the third signal symbol refers to the case where the frequency domain received signal includes three or more reference signal symbols, which will not be repeated here.

[0174] S22, respectively calculate the channel estimation values ​​H1, H2, H3 of the first signal symbol, the second signal symbol and the third signal symbol, and calculate the corresponding PO12, PO22, PO32 by the following first phase offset calculation formula:

[0175]

[0176]

[0177] .

[0178] Then, according to the first symbol spacing n12=3, the phase difference between PO12 and PO22, FO1 is calculated by the following formula:

[0179] .

[0180] According to the second symbol spacing n22=7, the phase difference between PO22 and PO32, FO2 is calculated by the following formula:

[0181] .

[0182] S23, for FO1, due to <W1a< And n12=3, the first flip number set W1{0,1,-1} is obtained. According to the first flip number set W1, the first frequency offset estimate value FO1 is phase flipped using the following calculation formula to obtain the first true frequency offset value set F1{F10=FO1, F11=FO1+ , F12=FO1- }:

[0183] .

[0184] Similarly, for FO2, due to <W2b< And n22=7, and the second flip number set W2{0,1,-1,2,-2,3,-3} is obtained. According to the second flip number set W2, the second frequency offset estimate value FO2 is phase flipped using the following calculation formula to obtain the second real frequency offset value set F2:

[0185] .

[0186] The second real frequency offset value set is specifically F2{F20=FO2, F21=FO2+ , F22=FO2- , F23=FO2+ , F24=FO2- , F25=FO2+ , F26=FO2- }.

[0187] S24, for the first real frequency offset value set F1, calculate the possible value range of each first real frequency offset value in the F1 set, so as to obtain multiple first frequency offset ranges: ; F11: ; F12: .

[0188] Similarly, for the second real frequency offset value set F2, the possible value range of each second real frequency offset value in the set F2 is calculated, so as to obtain each second frequency offset range: F20: ; F21: ; F22: ; F23: ; F24: ; F25: ; F26: .

[0189] S25, compare the first frequency offset range with each second frequency offset range, determine the combination of the ranges with intersections, and calculate the difference F3c between the corresponding first real frequency offset value and the second real frequency offset value, so as to obtain the difference set F3. Schematically, if there is an intersection between the frequency offset ranges of F10 and F20, then calculate F30=F10-F20, and add F30 to the F3 set. Repeat the above process until F10 is compared with all the second real frequency offset values ​​in the set F2, so as to finally obtain the set F3 {F30=F10-F20; F31=F10-F21; F32=F10-F22; F33=F11-F21; F34=F11-F23; F35=F11-F25; F36=F12-F22; F37=F12-F24; F38=F12-F26}.

[0190] S26, take the difference with the smallest absolute value in the set F3 as F3z, where F3z=F1j-F2k, that is, the first real frequency offset value corresponding to F3z is F1j (that is, the target first real frequency offset value), the first flip number is w1j, the second real frequency offset value is F2k (that is, the target second real frequency offset value), and the second flip number is w2k. Finally, considering that the second symbol spacing n22 is greater than the first symbol spacing n12, in order to estimate the FO with higher accuracy, F2k is used as the final real frequency offset value.

[0191] The frequency offset estimation method provided in the embodiment of the present invention can perform frequency offset estimation through the symbol spacing corresponding to the three reference signal symbols in the case of three reference signal symbols. This can not only increase the estimation range, but also further expand the estimation range by flipping, and ultimately obtain a frequency offset value with a larger range and higher accuracy.

[0192] In some embodiments of the present invention, a frequency offset estimation method is described in detail by taking an example where a frequency domain received signal only includes one reference signal symbol DMRSsymbol.

[0193] like Figure 7As shown, the frequency domain received signal is a PUSCH data sequence with 10 symbols. The signal symbol at position 2 in the PUSCH data sequence is a DMRS symbol, and the remaining positions are all Data symbols. On this basis, the frequency offset estimation method includes the following steps:

[0194] S31, based on the goal of minimizing the first symbol spacing and maximizing the second symbol spacing, determine that the DMRS symbol at position 2 is the first signal symbol, the Data symbol at position 1 is the second signal symbol, and the Data symbol at position 9 is the third signal symbol, such as Figure 8 At this time, the first symbol spacing n13 is the spacing between position 2 and position 1, n13=1, and the second symbol spacing n23 is the spacing between position 1 and position 9, n23=8.

[0195] The specific determination process of the first signal symbol, the second signal symbol and the third signal symbol refers to the case where the frequency domain received signal includes a reference signal symbol, which will not be repeated here.

[0196] S32, respectively calculating the constellation diagrams after equalization of the first signal symbol, the second signal symbol and the third signal symbol , , and standard constellation diagram , , , and then use the equalized constellation diagram and the standard constellation diagram to calculate the corresponding PO11, PO21, and PO31 through the following first phase offset calculation formula:

[0197] .

[0198] Then, according to the first symbol spacing n13=1, the phase difference between PO11 and PO21, FO1 is calculated by the following formula:

[0199] .

[0200] According to the second symbol spacing n23=8, the phase difference between PO21 and PO31, FO2 is calculated by the following formula:

[0201] .

[0202] S33, for FO1, due to <W1a< And n13=1, a first flip number set W1{W10=0} is obtained. According to the first flip number set W1, the first frequency offset estimate value FO1 is phase flipped using the following calculation formula to obtain a first true frequency offset value set F1{F10=FO1}:

[0203] .

[0204] Similarly, for FO2, due to <W2b< And n23=8, and the second flip number set W2{0,1,-1,2,-2,3,-3,4,-4} is obtained. According to the second flip number set W2, the second frequency offset estimate value FO2 is phase flipped using the following calculation formula to obtain the second real frequency offset value set F2:

[0205] .

[0206] The second real frequency offset value set is specifically F2{F20=FO2,F21=FO2+ , F22=FO2- , F23=FO2+ , F24=FO2- , F25=FO2+ , F26=FO2- , F27=FO2+ ,F28=FO2- }.

[0207] S34, for the first real frequency offset value set F1, calculate the possible value range of each first real frequency offset value in the F1 set, so as to obtain a first frequency offset range: .

[0208] Similarly, for the second real frequency offset value set F2, the possible value range of each second real frequency offset value in the set F2 is calculated, so as to obtain each second frequency offset range including: F20: ; F21: ; F22: ; F23: ; F24: ; F25: ; F26: ; F27: ; F28: .

[0209] S35, compare the first frequency offset range with each second frequency offset range, determine the combination of the ranges with intersections, and calculate the difference F3c between the corresponding first real frequency offset value and the second real frequency offset value, so as to obtain the difference set F3. Schematically, if there is an intersection between the frequency offset ranges of F10 and F20, then calculate F30=F10-F20, and add F30 to the F3 set. Repeat the above process until F10 is compared with all the second real frequency offset values ​​in the set F2, so as to finally obtain the set F3 {F30=F10-F20, F31=F10-F21; F32=F10-F22; F33=F10-F23; F34=F10-F24; F35=F10-F25; F36=F10-F26; F37=F10-F27; F38=F10-F28}.

[0210] S36, take the difference with the smallest absolute value in the set F3 as F3z, where F3z=F1j-F2k, that is, the first real frequency offset value corresponding to F3z is F1j (that is, the target first real frequency offset value), the first flip number is w1j, the second real frequency offset value is F2k (that is, the target second real frequency offset value), and the second flip number is w2k. Finally, considering that the second symbol spacing n23 is greater than the first symbol spacing n13, in order to estimate the FO with higher accuracy, F2k is used as the final real frequency offset value.

[0211] The frequency offset estimation method provided by the embodiment of the present invention can obtain a frequency offset value with a large frequency offset range and high accuracy even when there is only one reference signal symbol.

[0212] Based on any of the above embodiments, another embodiment of the present invention further provides an electronic device, which may include: a processor, a communications interface, a memory, and a communication bus, wherein the processor, the communications interface, and the memory communicate with each other via the communication bus. The processor may call logic instructions in the memory to execute the above frequency offset estimation method.

[0213] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0214] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0215] On the other hand, an embodiment of the present invention further provides a storage medium on which a plurality of instructions are stored, and the instructions are suitable for being loaded by a processor to execute the frequency offset estimation method provided in the above embodiments.

[0216] In addition, the logic instructions in the above-mentioned storage medium can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0217] On the other hand, an embodiment of the present invention further provides a computer program product. When the program code contained in the computer program product is executed by a processor in an electronic device, the frequency offset estimation method provided in the above embodiments is implemented.

[0218] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0219] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0220] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A frequency offset estimation method, characterized in that: include: Acquire a frequency domain received signal, where the frequency domain received signal includes at least one reference signal symbol; Determine a first symbol spacing and a second symbol spacing based on the frequency domain received signal, and calculate and obtain a first frequency offset estimation value and a second frequency offset estimation value accordingly; wherein the first symbol spacing is smaller than the second symbol spacing, and at least one of the first symbol spacing and the second symbol spacing is determined based on the reference signal symbol; Performing a phase flip on the first frequency offset estimation value according to the first symbol spacing, and at the same time, performing a phase flip on the second frequency offset estimation value according to the second symbol spacing, to correspondingly obtain a first true frequency offset value and a second true frequency offset value; Determine a matching first real frequency offset value and a matching second real frequency offset value according to the intersection between the first frequency offset range and the second frequency offset range, and determine a final real frequency offset value therefrom; The first frequency offset range is a value range of the first real frequency offset value, and the second frequency offset range is a value range of the second real frequency offset value; The phase flipping step includes: The first number value range and the second number value range are determined according to the first symbol spacing n1 and the second symbol spacing n2 respectively; wherein the first number value range is the absolute value of the first flip number less than The second number of times is within the range of the absolute value of the second flip number being less than The first flipping number and the second flipping number are integers; Select all values ​​from the first number value range and the second number value range respectively, so as to obtain a first flip number set and a second flip number set respectively; Performing phase flipping on the first frequency offset estimation value using each first flipping number in the first flipping number set to obtain a first real frequency offset value set; At the same time, the second frequency offset estimation value is phase-flipped using each second flip number in the second flip number set to obtain a second real frequency offset value set.

2. The method according to claim 1, characterized in that The first symbol spacing is the spacing between the first signal symbol and the second signal symbol, the second symbol spacing is the spacing between the second signal symbol and the third signal symbol, and at least one of the first signal symbol, the second signal symbol and the third signal symbol is a reference signal symbol.

3. The method according to claim 2, characterized in that The method further comprises: Based on the goal of minimizing the first symbol spacing and maximizing the second symbol spacing, a first signal symbol, a second signal symbol and a third signal symbol are determined from each signal symbol of the frequency domain received signal, wherein the first signal symbol is a reference signal symbol.

4. The method according to claim 3, characterized in that The step of determining the first signal symbol, the second signal symbol and the third signal symbol comprises: When the frequency domain received signal includes a reference signal symbol and at least two data symbols, the data symbol adjacent to the first signal symbol is used as a candidate second signal symbol, the farthest data symbol in the frequency domain received signal is used as a candidate third signal symbol, and the second signal symbol and the third signal symbol are determined from the candidate second signal symbols and the candidate third signal symbols based on the goal of maximizing the second symbol spacing.

5. The method according to claim 3, characterized in that The step of determining the first signal symbol, the second signal symbol and the third signal symbol comprises: When the frequency domain received signal includes two reference signal symbols, determining two groups of candidate first signal symbols and candidate third signal symbols according to the two reference signal symbols; Taking the data symbol adjacent to the candidate first signal symbol as the candidate second signal symbol; The second signal symbol and the third signal symbol are determined from candidate second signal symbols and candidate third signal symbols based on the goal of maximizing the second symbol distance, and the first signal symbol is further determined according to the third signal symbol.

6. The method according to claim 3, characterized in that The step of determining the first signal symbol, the second signal symbol and the third signal symbol comprises: When the frequency domain received signal includes at least three reference signal symbols, determining a candidate second signal symbol and a candidate third signal symbol from the at least three reference signal symbols according to a target of maximizing the second symbol spacing; According to the goal of minimizing the first symbol spacing, the reference signal symbol adjacent to the candidate second signal symbol is used as the first signal symbol, and then the final second signal symbol and third signal symbol are determined from the candidate second signal symbols and the candidate third signal symbols; wherein the second signal symbol and the third signal symbol are both reference signal symbols.

7. The method according to claim 3, characterized in that The step of calculating and obtaining the first frequency offset estimation value and the second frequency offset estimation value comprises: Performing phase offset estimation on the first signal symbol, the second signal symbol and the third signal symbol respectively, and correspondingly obtaining a first phase offset, a second phase offset and a third phase offset; The first frequency offset estimation value is calculated based on the first symbol spacing, the phase difference between the first phase offset and the second phase offset, and the second frequency offset estimation value is calculated based on the second symbol spacing, the phase difference between the second phase offset and the third phase offset.

8. The method according to claim 7, characterized in that The phase offset estimation step comprises: The phase offset estimation algorithm is used to perform phase offset estimation on the first signal symbol, the second signal symbol and the third signal symbol respectively. The phase offset estimation algorithm is at least one of a phase offset estimation algorithm based on a constellation diagram and a phase offset estimation algorithm based on a channel estimation value.

9. The method according to claim 8, characterized in that The phase offset estimation step comprises: In the case where the frequency domain received signal includes one reference signal symbol or two reference signal symbols, using an equalizer to process the first signal symbol, the second signal symbol, and the third signal symbol respectively and map them to a preset constellation diagram to obtain corresponding equalized constellation points; A first phase offset, a second phase offset and a third phase offset are calculated based on the equalized constellation point and the standard constellation point corresponding to the constellation diagram.

10. The method according to claim 8, characterized in that The phase offset estimation step comprises: In a case where the frequency domain received signal includes at least three reference signal symbols, channel estimation is performed on the first signal symbol, the second signal symbol, and the third signal symbol respectively, and a first channel estimation value, a second channel estimation value, and a third channel estimation value are correspondingly obtained; Calculate a first phase offset according to the first channel estimation value and the second channel estimation value; Calculate a second phase offset according to the first channel estimation value and the third channel estimation value; A third phase offset is obtained by calculation according to the second channel estimation value and the third channel estimation value.

11. The method according to claim 1, characterized in that The first frequency offset range and the second frequency offset range are obtained in the following manner; performing value range calculation on each first real frequency offset value in the first real frequency offset value set to obtain a first frequency offset range set; A value range calculation is performed on each second real frequency offset value in the second real frequency offset value set to obtain a second frequency offset range set.

12. The method according to claim 11, characterized in that The matching process of the first real frequency offset value and the second real frequency offset value includes: a matching step of arbitrarily selecting a first frequency offset range from the first frequency offset range set as the current first frequency offset range, comparing the first frequency offset range with each second frequency offset range in the second frequency offset range set, selecting a second frequency offset range with an intersection as the second frequency offset range that matches the current first frequency offset range, and selecting a first real frequency offset value corresponding to the current first frequency offset range as the matched first real frequency offset value, and a second real frequency offset value corresponding to the matched second frequency offset range as the matched second real frequency offset value; The repeating step is to repeatedly perform the matching step until all first frequency offset ranges in the first frequency offset range set are exhausted, so as to obtain at least one set of matched first real frequency offset values ​​and matched second real frequency offset values.

13. The method according to claim 1, characterized in that The matched first real frequency offset value and second real frequency offset value include multiple groups; The process of determining the final true frequency deviation value includes: Calculating an error between the matched first real frequency offset value and the matched second real frequency offset value to obtain a plurality of error values; A target first real frequency offset value and a target second real frequency offset value are determined from a plurality of sets of matched first real frequency offset values ​​and second real frequency offset values ​​according to the error value, and the target second real frequency offset value is used as a final real frequency offset value.

14. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method according to any one of claims 1 to 13 are implemented.

15. A storage medium, characterized in that: The storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor to execute the steps of the method according to any one of claims 1 to 13.

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