Frequency offset estimation method and device based on cyclic prefix, electronic equipment and storage medium

Abstract

The invention provides a frequency offset estimation method and device based on a cyclic prefix, electronic equipment and a storage medium, and relates to the technical field of communication. Determining at least one target path; dividing CP sampling points into at least one segmentation set according to the CP length of CP sampling and the time delay of the target diameter; screening the segmentation set to obtain a target segmentation set; according to the target reliability value of the target segmentation set, performing iterative combination on conjugate multiplication results of the target segmentation set to obtain a total combination conjugate multiplication weighted average value; and calculating a frequency offset estimation value of the received signal based on the total combination conjugate multiplication weighted average value. According to the method, the conjugate multiplication result is iteratively merged according to the target reliability value, the influence of noise and multipath interference is inhibited, and the accuracy of subsequently calculating the spectrum estimation value is improved. According to the invention, frequency offset estimation is carried out according to the multipath distribution and the target reliability value, and the accuracy of frequency offset estimation based on CP is improved.

Description

Technical Field

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

[0002] In the 5G New Radio (NR) communication system, due to the relative movement between the transceiver devices, environmental changes, and crystal oscillator temperature changes, there will be a frequency deviation between the transceiver devices, referred to as "frequency deviation". If the frequency deviation cannot be estimated well, it will seriously affect the subsequent channel estimation, demodulation and decoding performance. In severe cases, it will seriously undermine the stability of the system, causing the terminal to have to initiate a reconnection process with the transmitting device.

[0003] Conventional frequency offset estimation in NR systems is based on pilot signals, which usually include Tracking Reference Signal (TRS) and Synchronization Signal Block (SSB). Specific methods for frequency offset estimation include maximum likelihood, which constructs a likelihood equation and performs a refined search to determine the final frequency offset.

[0004] Since the NR system uses the Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) technology, in addition to relying on pilot signals, frequency offset estimation can also be completed based on CP. This is because in order to resist multipath channel fading, the CP-OFDM technology will copy and splice the tail data of the OFDM symbol before the OFDM symbol.

[0005] The scenarios where CP is usually used for frequency offset estimation are mostly those where pilot resources are insufficient or the frequency offset changes greatly. For scenarios with large Doppler, fast frequency offset changes or insufficient pilot resources (long period), the existing frequency offset estimation using CP has low accuracy. Summary of the invention

[0006] The present invention provides a frequency offset estimation method, device, electronic device and storage medium based on cyclic prefix, which are used to solve the defect of low precision of frequency offset estimation using CP in the prior art and improve the precision of frequency offset estimation using CP.

[0007] The present invention provides a frequency offset estimation method based on cyclic prefix, comprising: performing cyclic prefix CP sampling on a received signal to obtain a CP sampling point set; determining at least one target path according to the multipath distribution of the received signal and the power of the path; dividing the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the time delay of the target path; screening the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; iteratively merging the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value; and calculating the frequency offset estimation value of the received signal based on the total merged conjugate multiplication weighted average value.

[0008] According to the frequency offset estimation method based on cyclic prefix provided by the present invention, the conjugate multiplication results of the target segmentation set are iteratively merged according to the target reliability value of the target segmentation set to obtain the total merged conjugate multiplication weighted average value, including: according to the sorting results of the target reliability values ​​of all target segmentation sets from small to large, the sorted target reliability values, the sorted conjugate multiplication results and the sorted target segmentation sets are obtained, and the target segmentation sets, the target reliability values ​​and the conjugate multiplication results correspond to each other one by one; based on the previous merged reliability value and the current target reliability value, the current merged reliability value is calculated; based on the current merged reliability value and the current target reliability value, the current weighting coefficient is determined; according to the previous merged conjugate multiplication weighting coefficient The current merged conjugate multiplication weighted average value is calculated by taking the average value, the current weighting coefficient and the current conjugate multiplication result; the current merged reliability value is taken as the previous merged reliability value to iteratively update the current weighting coefficient, and in the iterative update of the current weighting coefficient, the target reliability value ranked first is taken as the initial merged reliability value; the current merged conjugate multiplication weighted average value is taken as the previous merged conjugate multiplication weighted average value to iteratively update the current merged conjugate multiplication weighted average value, and in the iterative update of the current merged conjugate multiplication weighted average value, the conjugate multiplication result ranked first is taken as the initial merged conjugate multiplication weighted average value, and the last updated current merged conjugate multiplication weighted average value is taken as the total merged conjugate multiplication weighted average value.

[0009] According to the cyclic prefix-based frequency offset estimation method provided by the present invention, the CP sampling points in the CP sampling point set are divided into at least one segmentation set according to the CP length of CP sampling and the delay of the target path, including: obtaining the starting sampling time point corresponding to the target path within the CP length according to the delay of the target path; dividing the CP length into at least one CP sampling time period according to the starting sampling time point, and taking the CP sampling points in each CP sampling time period as a segmentation set.

[0010] According to the frequency offset estimation method based on cyclic prefix provided by the present invention, a slicing set includes at least one target path, each target path includes its own starting sampling time point, and the reliability value of the slicing set is determined based on the following steps: according to the CP sampling time period, the latest sampling time point of the slicing set is obtained, and according to the time delay of the target path, the target path whose starting sampling time point is earlier than the latest sampling time point is used as the signal path of the slicing set, and the target path whose starting sampling time point is later than the latest sampling time point is used as the interference path of the slicing set; the reliability value of the slicing set is calculated according to the sum of the powers of the signal path of the slicing set, the sum of the powers of the interference path of the slicing set, the number of CP sampling points of the slicing set, and the linear value of the signal-to-noise ratio of the received signal.

[0011] According to the cyclic prefix-based frequency offset estimation method provided by the present invention, a segmentation set is screened according to the reliability value of the segmentation set to obtain a target segmentation set, including: obtaining a comparison value of the segmentation set based on a ratio of the reliability value of the segmentation set to the reliability value of the minimum segmentation set; traversing the comparison values ​​of all segmentation sets, and when the comparison value of the segmentation set is greater than the set comparison value, removing the segmentation set whose comparison value is greater than the set comparison value to obtain the target segmentation set.

[0012] According to the frequency offset estimation method based on cyclic prefix provided by the present invention, at least one target path is determined according to the multipath distribution of the received signal and the power of the path, including: obtaining the multipath distribution based on the tracking reference signal to obtain at least one path and the power of at least one path, sorting the power of the path, and selecting a set number of paths as the first path according to the sorting result of the power of the path from large to small; if the first path includes a transcending path whose path delay is greater than the CP length, merging all the transcending paths into a total path; and obtaining at least one target path based on the total path and the unmerged first path.

[0013] According to the frequency offset estimation method based on cyclic prefix provided by the present invention, the delay of the target path is determined based on the following steps: the delays of all transcending paths are combined into a set delay, and the delay of the target path is obtained based on the set delay and the delay of the uncombined target path.

[0014] According to the cyclic prefix-based frequency offset estimation method provided by the present invention, the target segmentation set includes segmentation sets of different orthogonal frequency division multiplexing OFDM symbols, and the segmentation set is screened according to the reliability value of the segmentation set. After obtaining the target segmentation set, it also includes: for the same OFDM symbol, according to the target symbol reliability value of the segmentation set of the OFDM symbol, iteratively merging the symbol conjugate multiplication results of the segmentation set of the OFDM symbol to obtain a symbol-level merged conjugate multiplication weighted average value and a symbol-level merged reliability value; based on the symbol-level merged reliability value, iteratively merging the symbol-level merged conjugate multiplication weighted average value again to obtain an updated symbol-level conjugate multiplication weighted average value; based on the updated total merged conjugate multiplication weighted average value, calculating the frequency offset estimation value of the received signal.

[0015] The present invention also provides a frequency offset estimation device based on cyclic prefix, comprising: a sampling module, used to perform cyclic prefix CP sampling on a received signal to obtain a CP sampling point set; a determination module, used to determine at least one target path according to the multipath distribution of the received signal and the power of the path; a segmentation module, used to divide the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; a screening module, used to screen the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; a merging module, used to iteratively merge the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value; a frequency offset estimation module, used to calculate the frequency offset estimation value of the received signal based on the total merged conjugate multiplication weighted average value.

[0016] The present invention also provides 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 computer program, any of the above-mentioned frequency offset estimation methods based on cyclic prefix is ​​implemented.

[0017] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the method for estimating a frequency offset based on a cyclic prefix as described above is implemented.

[0018] The frequency offset estimation method, device, electronic device and storage medium based on cyclic prefix provided by the present invention obtain a CP sampling point set by performing cyclic prefix CP sampling on the received signal; determine at least one target path according to the multipath distribution of the received signal and the power of the path; divide the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; screen the segmentation set according to the reliability value of the segmentation set to obtain the target segmentation set; iteratively merge the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain the total merged conjugate multiplication weighted average value; calculate the frequency offset estimation value of the received signal based on the total merged conjugate multiplication weighted average value. The present invention iteratively merges the conjugate multiplication results according to the target reliability value, suppresses the influence of multipath interference and noise, and improves the accuracy of the subsequent calculation of the spectrum estimation value. The present invention performs frequency offset estimation according to the multipath distribution and the target reliability value, and improves the accuracy of frequency offset estimation based on CP. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0020] Figure 1 It is a flow chart of a frequency offset estimation method based on cyclic prefix provided by the present invention.

[0021] Figure 2 It is a schematic diagram of the target diameter provided by the present invention.

[0022] Figure 3 This is the relationship curve 1 between the frequency offset estimation value and the signal-to-noise ratio provided by the present invention.

[0023] Figure 4 This is the second relationship curve between the frequency offset estimation value and the signal-to-noise ratio provided by the present invention.

[0024] Figure 5 It is a structural schematic diagram of a frequency offset estimation device based on cyclic prefix provided by the present invention.

[0025] Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Combine the following Figure 1-Figure 6 The present invention describes a frequency offset estimation method, device and electronic device based on cyclic prefix.

[0028] Figure 1 is a flow chart of a frequency offset estimation method based on cyclic prefix provided by the present invention, such as Figure 1 As shown, the frequency offset estimation method based on cyclic prefix includes steps S100 to S600, and each step is specifically described as follows.

[0029] S100: Perform cyclic prefix CP sampling on the received signal to obtain a CP sampling point set.

[0030] like Figure 2 As shown, the received signal is obtained at the receiving end of the signal, and the cyclic prefix (CP) sampling is performed on the received signal to obtain multiple CP sampling points, and then a CP sampling point set is obtained. A CP sampling point includes the signal at the CP point and the OFDM data signal corresponding to the CP point. The expression formula of the signal at the CP point and the OFDM data signal corresponding to the CP point is as follows.

[0031] ; ; in, For the A signal of CP point, For the The OFDM data signal corresponding to the CP point is is the number of sampling points of OFDM data signal, is the number of diameters, For the diameter, is an imaginary number, is the frequency deviation value of the received signal, is the sampling interval of the CP sampling point, For the The delay of the stripe, For the The impulse response of the strip diameter, For the White noise with CP points, For the The white noise of the OFDM data signal corresponding to the CP point, To send a signal.

[0032] S200: Determine at least one target path according to the multipath distribution of the received signal and the power of the paths.

[0033] Get the multipath distribution corresponding to the received signal to get the path distribution. Get the power of each path. The power of the path represents the ability of the path. The greater the power of the path, the stronger the energy of the path.

[0034] According to the power of the path, a set number of paths with the strongest energy are selected as target paths to obtain a target path set.

[0035] S300: Divide the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path.

[0036] The CP sampling point includes the superimposed signals corresponding to multiple target paths. According to the delay size of the target path, the order in which the target path is collected can be determined. The CP length is divided according to the order in which the target path is collected to obtain at least one CP sampling time period, and the CP sampling points in each CP sampling time period are used as a segmentation set.

[0037] S400: Screening the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set.

[0038] The reliability value of each segmentation set is calculated, and the reliability value represents the reliability of the signal strength of the CP sampling points in the segmentation set.

[0039] From all segmentation sets, the segmentation sets with lower reliability values ​​are screened out to obtain the target segmentation set.

[0040] S500: Iteratively merge the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value.

[0041] Calculate the conjugate multiplication result of each target segmentation set. The calculation formula of the conjugate multiplication result is as follows.

[0042] ; in, For the CP point signal The conjugate signal of For the A target segmentation set, For the The OFDM data signal corresponding to the CP point is For the The conjugate multiplication result of the target segmentation set.

[0043] The target segmentation set, the target reliability value and the conjugate multiplication result correspond to each other. The target reliability values ​​are sorted to obtain the sorted target reliability values, and then the sorted conjugate multiplication weighted average is obtained.

[0044] According to the sorted target reliability values, the sorted conjugate multiplication results are iteratively merged to obtain the total merged conjugate multiplication weighted average of all target segmentation sets.

[0045] S600: Calculate a frequency offset estimation value of a received signal based on the total combined conjugate multiplied weighted average value.

[0046] The frequency offset estimation value of the received signal is calculated based on the total combined conjugate multiplied weighted average value, and the calculation formula is as follows.

[0047] ; (1) in, is the frequency offset estimate, is the number of CP sampling points in the CP sampling point set, is the number of sampling points of OFDM data signal, is the sampling interval of the CP sampling point, is the total combined conjugate multiplicative weighted average.

[0048] The frequency offset estimation method based on cyclic prefix provided by the present invention obtains a CP sampling point set by performing cyclic prefix CP sampling on a received signal; determines at least one target path according to the multipath distribution of the received signal and the power of the path; divides the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; screens the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; iteratively combines the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total combined conjugate multiplication weighted average value; and calculates the frequency offset estimation value of the received signal based on the total combined conjugate multiplication weighted average value. The present invention iteratively combines the conjugate multiplication results according to the target reliability value, suppresses the influence of multipath interference and noise, and improves the accuracy of the subsequent calculation of the spectrum estimation value. The present invention performs frequency offset estimation according to the multipath distribution and the target reliability value, and improves the accuracy of frequency offset estimation based on CP.

[0049] The present invention does not modify the specific configuration method of CP in the existing CP-OFDM system, but only improves the frequency offset estimation from the perspective of the algorithm, and has good applicability. The present invention proposes the criterion of CP reliability for the first time. This criterion is obtained based on theoretical analysis and is conducive to quantitatively evaluating the performance of CP frequency discrimination results. Based on the CP reliability and merging criteria, the present invention optimizes the performance of the CP frequency discrimination (frequency offset estimation based on CP) algorithm.

[0050] Based on the above embodiment, according to the target reliability value of the target segmentation set, the conjugate multiplication results of the target segmentation set are iteratively merged to obtain the total merged conjugate multiplication weighted average value, including: according to the sorting results of the target reliability values ​​of all target segmentation sets from small to large, the sorted target reliability values, the sorted conjugate multiplication results and the sorted target segmentation sets are obtained, and the target segmentation sets, the target reliability values ​​and the conjugate multiplication results correspond to each other one by one; based on the previous merged reliability value and the current target reliability value, the current merged reliability value is calculated; based on the current merged reliability value and the current target reliability value, the current weighting coefficient is determined; based on the previous merged conjugate multiplication weighted average value, the current ... The weight coefficient and the current conjugate multiplication result are used to calculate the current merged conjugate multiplication weighted average value; the current merged reliability value is used as the previous merged reliability value to iteratively update the current weight coefficient, and in the iterative update of the current weight coefficient, the target reliability value ranked first is used as the initial merged reliability value; the current merged conjugate multiplication weighted average value is used as the previous merged conjugate multiplication weighted average value to iteratively update the current merged conjugate multiplication weighted average value, and in the iterative update of the current merged conjugate multiplication weighted average value, the conjugate multiplication result ranked first is used as the initial merged conjugate multiplication weighted average value, and the last updated current merged conjugate multiplication weighted average value is used as the total merged conjugate multiplication weighted average value.

[0051] According to the results of sorting all target reliability values ​​from small to large, the sorted target reliability values, the sorted conjugate multiplication results and the sorted target segmentation set are obtained. For example, the sorted target reliability values ​​include , ..., , ..., The sorted conjugate multiplication results include , ..., , ..., The sorted target segmentation set includes , ..., , ..., . Calculate the total combined conjugate multiplicative weighted mean.

[0052] ; ; ; ， ， ; (2) in, To be the first The combined reliability value is used as the current combined reliability value. To be the first The combined reliability value is used as the previous combined reliability value. To be the first The target reliability value is used as the current target reliability value. To be the first The conjugate multiplication result is is the initial combined reliability value, is the first-ranked target reliability value, is the initial combined conjugate multiplication weighted average, is the conjugate multiplication result of the first order, To be the first The previous weighting coefficients are used as the current weighting coefficients, To be the first The combined conjugate multiplication weighted average is used as the previous combined conjugate multiplication weighted average, To be the first The combined conjugate multiplication weighted average is used as the current combined conjugate multiplication weighted average. The number of target split sets.

[0053] The current combined reliability value is used as the previous combined reliability value to iteratively update the current weighting coefficient; the current combined conjugate multiplication weighted average value is used as the previous combined conjugate multiplication weighted average value to iteratively update the current combined conjugate multiplication weighted average value.

[0054] For example, ; ; . ; ; . And so on, iterative calculation is performed, and the weighted average value of the current merge conjugate multiplication last updated is As the total combined conjugate multiplicative weighted average ,Right now = .

[0055] Further, Substitute into formula (1) to calculate the frequency offset estimate.

[0056] The present invention iteratively calculates the current weighting coefficient according to the target reliability value, realizes the accurate weighted combination of the previous combined conjugate multiplication weighted average value and the current conjugate multiplication result, which is beneficial to improve the accuracy of calculating the total combined conjugate multiplication weighted average value.

[0057] Based on the above embodiment, the target slice set includes a slice set of different orthogonal frequency division multiplexing OFDM symbols. The slice set is screened according to the reliability value of the slice set. After obtaining the target slice set, it also includes: for the same OFDM symbol, according to the target symbol reliability value of the slice set of the OFDM symbol, the symbol conjugate multiplication weighted average value of the slice set of the OFDM symbol is iteratively merged to obtain a symbol-level merged conjugate multiplication weighted average value and a symbol-level merged reliability value; based on the symbol-level merged reliability value, the symbol-level merged conjugate multiplication weighted average value is iteratively merged again to obtain an updated total merged conjugate multiplication weighted average value; based on the updated total merged conjugate multiplication weighted average value, the frequency offset estimation value of the received signal is calculated.

[0058] According to the above formula (2), for the same OFDM symbol, the symbol conjugate multiplication weighted average values ​​of the OFDM symbol segmentation set are iteratively combined according to the target symbol reliability value of the OFDM symbol segmentation set to obtain the symbol-level combined conjugate multiplication weighted average value. The last updated current combined reliability value is used as the symbol-level combined reliability value. The symbol-level combined conjugate multiplication weighted average value of each orthogonal frequency division multiplexing (OFDM) symbol is calculated. , s is the number of OFDM symbols, s=1,...,S. Calculate the symbol-level combined reliability value of each OFDM symbol , s is the number of OFDM symbols, s=1,...,S.

[0059] All and Sort in ascending order to get { , ..., , ..., }and{ , ..., , ..., Repeat the above steps, and iteratively merge all symbol-level combined conjugate multiplication weighted averages according to all symbol-level combined reliability values ​​to obtain the updated total combined conjugate multiplication weighted average. .

[0060] ; ; ; ， ， ; in, To be the first The symbol-level combined conjugate multiplication weighted average is used as the current symbol-level combined conjugate multiplication weighted average, is the total combined conjugate multiplication weighted average of the current target, is the total combined conjugate multiplication weighted average of the previous target, is the initial re-merged reliability value, is the combined reliability value of the first symbol level, is the initial target total combined conjugate multiplication weighted average, is the first symbol-level combined conjugate multiplication weighted average, is the sequence number of the OFDM symbol, is the total number of OFDM symbols, is the current re-merged reliability value, is the previous re-merged reliability value, To be the first symbol-level combined reliability value as the current symbol-level combined reliability value, Re-weight the current factor.

[0061] The current target total merged conjugate multiplication weighted average obtained from the last update , as the updated total combined conjugate multiplicative weighted average .Right now The frequency offset estimation value of the received signal is calculated based on the updated total combined conjugate multiplied weighted average value and formula (1).

[0062] Based on the above embodiment, according to the CP length of CP sampling and the delay of the target path, the CP sampling points in the CP sampling point set are divided into at least one segmentation set, including: according to the delay of the target path, obtaining the start sampling time point corresponding to the target path within the CP length; dividing the CP length into at least one CP sampling time period according to the start sampling time point, and taking the CP sampling points in each CP sampling time period as a segmentation set.

[0063] According to the time delay of the target path, the starting sampling time point corresponding to the target path within the CP length is obtained. The CP starting time point and the CP ending time point are determined according to the CP length. Figure 2As shown, the target path includes the first path, the second path and the third path. The start sampling time point of the first path is T0, and T0 also belongs to the CP start time point. The start sampling time point of the second path is T1. The start sampling time point of the third path is T2. The start sampling time points corresponding to the target path within the CP length include T0 and T1. If the CP end time point is T3. The CP sampling time period includes the T0-T1 time period and the T1-T3 time period. The CP sampling points in the T0-T1 time period are taken as the first segmentation set. The CP sampling points in the T1-T3 time period are taken as the second segmentation set.

[0064] The present invention divides the CP length according to the time delay of the target path to obtain the CP sampling time period, and then obtains the segmentation set, thereby realizing accurate segmentation of the CP sampling point set, which is beneficial to improving the accuracy of subsequent calculation of the frequency offset estimation value.

[0065] Based on the above embodiment, a slicing set includes at least one target path, each target path includes its own starting sampling time point, and the reliability value of the slicing set is determined based on the following steps: according to the CP sampling time period, the latest sampling time point of the slicing set is obtained, and according to the delay of the target path, the target path whose starting sampling time point is earlier than the latest sampling time point is used as the signal path of the slicing set, and the target path whose starting sampling time point is later than the latest sampling time point is used as the interference path of the slicing set; the reliability value of the slicing set is calculated according to the sum of the powers of the signal path of the slicing set, the sum of the powers of the interference path of the slicing set, the number of CP sampling points of the slicing set, and the linear value of the signal-to-noise ratio of the received signal.

[0066] Calculate the reliability value of each segmentation set. According to the CP sampling time period, obtain the latest sampling time point of the segmentation set. According to the delay of the target path, take the target path whose start sampling time point is earlier than the latest sampling time point as the signal path of the segmentation set, and take the target path whose start sampling time point is later than the latest sampling time point as the interference path of the segmentation set. For example, Figure 2 As shown, there are two slicing sets in total, namely the first slicing set and the second slicing set. The first slicing set includes CP sampling points in the T0-T1 time period. The first slicing set includes CP sampling points in the T1-T3 time period. The latest sampling time of the second slicing set is T3. The starting sampling time point of the first path is T0. The starting sampling time point of the second path is T1. The starting sampling time point of the third path is T2. T0 and T1 are earlier than T3, so the signal path of the second slicing set includes the first path and the second path. T2 is later than T3, so the interference path of the slicing set includes the third path.

[0067] The reliability value of the segmented set is calculated according to the sum of the power of the signal path of the segmented set, the sum of the power of the interference path of the segmented set, the number of CP sampling points of the segmented set, and the linear value of the signal-to-noise ratio of the received signal. The calculation formula is as follows.

[0068] ; in, For the Reliability value, For the The number of sampling points in the split set, For the The set of interference paths of the segmented set, For the The signal path set of the segmented set, For the diameter, is the power of the diameter, For the The sum of the power of the interference paths of the sliced ​​set, For the The sum of the power of the signal paths of the split sets, is the linear value of the signal-to-noise ratio of the received signal.

[0069] The present invention calculates the reliability value according to the power sum of the signal path of the segmented set, the power sum of the interference path of the segmented set, the number of CP sampling points of the segmented set and the linear value of the signal-to-noise ratio, thereby accurately describing the reliability of the estimation result.

[0070] Based on the above embodiment, the segmentation set is screened according to the reliability value of the segmentation set to obtain a target segmentation set, including: obtaining a comparison value of the segmentation set based on a ratio of the reliability value of the segmentation set to the reliability value of the minimum segmentation set; traversing the comparison values ​​of all segmentation sets, and when the comparison value of the segmentation set is greater than the set comparison value, removing the segmentation set whose comparison value is greater than the set comparison value to obtain the target segmentation set.

[0071] The comparison value of the segmentation set is obtained according to the ratio of the reliability value of the segmentation set to the reliability value of the minimum segmentation set.

[0072] ; in, For the The comparison value of the partitioned set, is the reliability value of the minimum segmentation set, For the The reliability value of a segmentation set.

[0073] Set the comparison value to If , indicating that the reliability of this segmentation set is lower than that of all segmentation sets, then the corresponding The segmentation set is deleted. , indicating that the reliability of this segmentation set is higher than that of all segmentation sets, then the first segmentation set is retained. A collection of segments.

[0074] According to the comparison values ​​of the segmentation sets, the segmentation sets with relatively low reliability are deleted, and the retained segmentation sets are used as the target segmentation sets.

[0075] The present invention deletes the segmentation set with low reliability according to the comparison value, reduces the requirement for the accuracy of multipath distribution information, and is beneficial to improving the accuracy of the subsequent calculation of the frequency offset estimation value.

[0076] Based on the above embodiment, at least one target path is determined according to the multipath distribution of the received signal and the power of the path, including: obtaining the multipath distribution based on the tracking reference signal to obtain at least one path and the power of at least one path, sorting the power of the path, and selecting a set number of paths as the first path according to the sorting result of the power of the path from large to small; if the first path includes a transcending path whose path delay is greater than the CP length, merging all the transcending paths into a total path; and obtaining at least one target path based on the total path and the unmerged first path.

[0077] Doppler calibration is performed based on the Tracking Reference Signal (TRS), and multipath distribution and signal-to-noise ratio are output. Based on the multipath distribution and signal-to-noise ratio, the optimal cyclic prefix-based frequency offset estimation (CP frequency discrimination) is achieved.

[0078] Obtain the power of each path in the multipath distribution, sort the power of the paths, and select a set number of paths with larger power as the first path based on the multipath distribution and sorting results. For example, set the number to N. Sort the power of the paths from small to large, select the last N paths in the sorting as the first path, and obtain the first path set. If there is a first path in the first path set whose delay is greater than the CP length, then the first path is taken as the transcending path. Figure 2 As shown, the first path set includes the first path, the second path and the third path. The delay of the third path is greater than the CP length, and the third path is a transcending path.

[0079] If there are multiple transcending paths in the first path set, all the transcending paths are merged into a total path, for example, the total path is represented by a path number. According to the total path and other unmerged first paths, a target path set is obtained, and the target path set includes at least one target path.

[0080] The present invention simplifies the target path by combining all the transcending paths into one total path, which is beneficial to reducing the amount of calculation for subsequent calculation of the frequency deviation estimation value.

[0081] Based on the above embodiment, the delay of the target path is determined based on the following steps: merging the delays of all transcending paths into a set delay, and obtaining the delay of the target path based on the set delay and the delay of the unmerged target path.

[0082] For the target path set, calculate the delay set of the corresponding target path. According to the delays of all first paths in the first path set, obtain the delay set of the first path . Delete all the delays of the transcending paths from the delay set of the first path to obtain the delay set of the initial target path . Combine all the delays of the transcendental paths into one set delay, for example, ,in, is the number of CP sampling points in the CP sampling point set, is the set delay. Add the set delay to the delay set of the initial target path. The delay set of the target path is obtained The delay set of the target path Includes the set delay and the delay of the unmerged target path.

[0083] The present invention simplifies the calculation of the target path delay by combining the delay of the transcending path into a set delay, which is beneficial to reducing the calculation amount of the subsequent calculation of the frequency offset estimation value.

[0084] Furthermore, for the target path set, the power set of the corresponding target path is calculated, and the sum of the powers of all the transcending paths is taken as the power of the total path.

[0085] ; in, is the set of all transcendental paths, , is the power beyond the diameter, For the diameter, is the power of the total diameter, It is the sum of the powers of all the paths beyond which the

[0086] The power set of the target path is obtained based on the combined power and the power of the uncombined target path (not the target path of the transcending path). The reliability value of the segmentation set is then calculated based on the power set of the target path.

[0087] The frequency offset estimation method based on cyclic prefix of the present invention can evaluate the influence of multipath distribution interference, and can also screen the time domain sampling points in the CP area, thereby ensuring the CP discrimination performance. For a given signal-to-noise ratio, the present invention effectively suppresses the influence of multipath interference and noise, thereby equivalently improving the effective discrimination range of Doppler. In addition, for rapid changes in Doppler, such as rapid temperature changes in the terminal crystal oscillator, the present invention can also flexibly choose whether to identify the frequency offset estimation result according to the symbol. In particular, the setting method of CP in the existing CP-OFDM is not modified, and only enhancements are made from the algorithm perspective, so it has good applicability.

[0088] like Figure 3 As shown in the figure, for the New Radio Frequency Range 1 (NR FR1), the subcarrier spacing (SCS) is 15KHz, the crystal oscillator has nonlinear temperature variation, and the TRS period is 10ms, it is not suitable to use a low filter coefficient to smooth the frequency deviation, otherwise it will cause a large hysteresis error and it will be difficult to meet the frequency deviation requirements of services such as high-precision positioning.

[0089] Based on CP, the frequency offset estimation is performed, and the channel impulse response result of TRS is directly used as the channel to execute the algorithm. Given the Additive White Gaussian Noise (AWGN) channel and single path, the single symbol estimation performance under the change of the frequency offset estimation value with the Sin function is obtained. Since the present invention does not involve operations such as filtering, the performance shown below only includes the comparison of the open-loop single CP frequency discrimination (single time slot) performance. Figure 3 As shown in the figure, in a single-path channel, even if the frequency offset estimation value changes rapidly (the Sin function period is 10s from -100Hz to +100Hz), the frequency offset estimation value at the time limit (slot) level is consistent with the frequency offset performance of a channel with static frequency offset (AWGN), indicating that the frequency offset estimation value at the slot level is little affected by the changing frequency offset. In practical applications, the number of slot combinations can be appropriately increased, thereby appropriately sacrificing tracking capabilities to obtain greater noise reduction benefits.

[0090] like Figure 4 As shown in the figure, in the cluster delay line model, the delay extension 100 (CDLA-100) channel, simply selecting points in the baseline solution and then performing frequency offset estimation will cause an estimation platform. However, the frequency offset estimation method proposed in the invention can significantly improve the root mean square error (RMSE) of the frequency offset estimation value, and there is no estimation platform.

[0091] The frequency offset estimation device based on cyclic prefix provided by the present invention is described below. The frequency offset estimation device based on cyclic prefix described below and the frequency offset estimation method based on cyclic prefix described above can be referred to each other.

[0092] like Figure 5 As shown, a frequency offset estimation device based on cyclic prefix includes: a sampling module 501, which is used to perform cyclic prefix CP sampling on a received signal to obtain a CP sampling point set.

[0093] The determination module 502 is used to determine at least one target path according to the multipath distribution of the received signal and the power of the path.

[0094] The segmentation module 503 is configured to divide the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path.

[0095] The screening module 504 is used to screen the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set.

[0096] The merging module 505 is used to iteratively merge the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value.

[0097] The frequency offset estimation module 506 is used to calculate the frequency offset estimation value of the received signal based on the total combined conjugate multiplied weighted average value.

[0098] The cyclic prefix-based frequency offset estimation device provided by the present invention obtains a CP sampling point set by performing cyclic prefix CP sampling on a received signal; determines at least one target path according to the multipath distribution of the received signal and the power of the path; divides the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; screens the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; iteratively combines the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total combined conjugate multiplication weighted average value; and calculates the frequency offset estimation value of the received signal based on the total combined conjugate multiplication weighted average value. The present invention iteratively combines the conjugate multiplication results of the segmentation set according to the target reliability value, effectively suppresses the influence of multipath interference and noise, and improves the accuracy of the subsequent calculation of the spectrum estimation value. The present invention performs frequency offset estimation according to the multipath distribution and the target reliability value, and improves the accuracy of frequency offset estimation based on CP.

[0099] In one embodiment, the merging module 505 is used to: obtain the sorted target reliability value, the sorted conjugate multiplication result and the sorted target segmentation set according to the result of sorting the target reliability values ​​of all target segmentation sets from small to large, and the target segmentation set, the target reliability value and the conjugate multiplication result correspond to each other one by one; calculate the current merged reliability value based on the previous merged reliability value and the current target reliability value; determine the current weighting coefficient based on the current merged reliability value and the current target reliability value; calculate the current merged conjugate phase according to the weighted average value of the previous merged conjugate multiplication, the current weighting coefficient and the current conjugate multiplication result. multiply weighted average; take the current combined reliability value as the previous combined reliability value to iteratively update the current weighting coefficient, and in the iterative update of the current weighting coefficient, take the target reliability value ranked first as the initial combined reliability value; take the current combined conjugate multiplication weighted average as the previous combined conjugate multiplication weighted average to iteratively update the current combined conjugate multiplication weighted average, and in the iterative update of the current combined conjugate multiplication weighted average, take the conjugate multiplication result ranked first as the initial combined conjugate multiplication weighted average, and take the last updated current combined conjugate multiplication weighted average as the total combined conjugate multiplication weighted average.

[0100] In one embodiment, the segmentation module 503 is used to: obtain the starting sampling time point corresponding to the target path within the CP length according to the delay of the target path; divide the CP length into at least one CP sampling time period according to the starting sampling time point, and use the CP sampling points in each CP sampling time period as a segmentation set.

[0101] In one embodiment, a slicing set includes at least one target path, each target path includes its own starting sampling time point, and the screening module 504 is further used to: obtain the latest sampling time point of the slicing set according to the CP sampling time period, and according to the delay of the target path, use the target path whose starting sampling time point is earlier than the latest sampling time point as the signal path of the slicing set, and use the target path whose starting sampling time point is later than the latest sampling time point as the interference path of the slicing set; calculate the reliability value of the slicing set according to the sum of the powers of the signal path of the slicing set, the sum of the powers of the interference path of the slicing set, the number of CP sampling points of the slicing set, and the linear value of the signal-to-noise ratio of the received signal.

[0102] In one embodiment, the screening module 504 is used to: obtain a comparison value of the segmentation set based on the ratio of the reliability value of the segmentation set to the reliability value of the minimum segmentation set; traverse the comparison values ​​of all segmentation sets, and when the comparison value of the segmentation set is greater than the set comparison value, remove the segmentation set whose comparison value is greater than the set comparison value to obtain the target segmentation set.

[0103] In one embodiment, the determination module 502 is used to: obtain multipath distribution based on the tracking reference signal to obtain at least one path and the power of at least one path, sort the powers of the paths, and select a set number of paths as the first path according to the sorting results of the powers of the paths from large to small; if the first path includes a transcending path whose path delay is greater than the CP length, merge all the transcending paths into a total path; and obtain at least one target path based on the total path and the unmerged first path.

[0104] In one embodiment, the determination module 502 is further configured to: combine the delays of all transcending paths into a set delay, and obtain the delay of the target path based on the set delay and the delay of the uncombined target path.

[0105] In one embodiment, the target segmentation set includes segmentation sets of different orthogonal frequency division multiplexing OFDM symbols, and the merging module 505 is also used to: for the same OFDM symbol, according to the target symbol reliability value of the segmentation set of the OFDM symbol, iteratively merge the symbol conjugate multiplication results of the segmentation set of the OFDM symbol to obtain a symbol-level merged conjugate multiplication weighted average value and a symbol-level merged reliability value; based on the symbol-level merged reliability value, iteratively merge the symbol-level merged conjugate multiplication weighted average value again to obtain an updated total merged conjugate multiplication weighted average value. The frequency offset estimation module 506 is also used to: calculate the frequency offset estimation value of the received signal based on the updated total merged weighted conjugate multiplication weighted average value.

[0106] Figure 6 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630 and a communication bus 640, wherein the processor 610, the communication interface 620 and the memory 630 communicate with each other through the communication bus 640. The processor 610 may call the logic instructions in the memory 630 to execute the frequency offset estimation method based on the cyclic prefix, the method comprising: performing cyclic prefix CP sampling on the received signal to obtain a CP sampling point set; determining at least one target path according to the multipath distribution and path power of the received signal; dividing the CP sampling points in the CP sampling point set into at least one slicing set according to the CP length of the CP sampling and the delay of the target path; screening the slicing set according to the reliability value of the slicing set to obtain a target slicing set; iteratively merging the conjugate multiplication results of the target slicing set according to the target reliability value of the target slicing set to obtain a total merged conjugate multiplication weighted average; and calculating the frequency offset estimation value of the received signal based on the total merged conjugate multiplication weighted average.

[0107] In addition, the logic instructions in the above-mentioned memory 630 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an 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, and the computer software product is stored in a storage medium, including a number of 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. Various media that can store program codes.

[0108] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the processor executes the cyclic prefix-based frequency offset estimation method provided by the above-mentioned methods, the method comprising: performing cyclic prefix CP sampling on the received signal to obtain a CP sampling point set; determining at least one target path according to the multipath distribution of the received signal and the power of the path; dividing the CP sampling points in the CP sampling point set into at least one cut set according to the CP length of the CP sampling and the delay of the target path; screening the cut set according to the reliability value of the cut set to obtain a target cut set; iteratively merging the conjugate multiplication results of the target cut set according to the target reliability value of the target cut set to obtain a total merged conjugate multiplication weighted average; and calculating the frequency offset estimation value of the received signal based on the total merged conjugate multiplication weighted average.

[0109] 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.

[0110] 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.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency offset estimation method based on cyclic prefix, characterized in that: include: Perform cyclic prefix CP sampling on the received signal to obtain a CP sampling point set; Determining at least one target path according to the multipath distribution and path power of the received signal; Dividing the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; Screening the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; Iteratively merging the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value; A frequency offset estimation value of the received signal is calculated based on the total combined conjugate multiplied weighted average value.

2. The frequency offset estimation method based on cyclic prefix according to claim 1, characterized in that: The iterative merging of the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value includes: According to the results of sorting the target reliability values ​​of all the target segmentation sets from small to large, obtaining sorted target reliability values, sorted conjugate multiplication results, and sorted target segmentation sets, wherein the target segmentation sets, the target reliability values, and the conjugate multiplication results correspond to each other one by one; Calculate a current combined reliability value based on a previous combined reliability value and a current target reliability value; Determining a current weighting coefficient based on the current combined reliability value and the current target reliability value; Calculate the current combined conjugate multiplication weighted average value according to the previous combined conjugate multiplication weighted average value, the current weighting coefficient and the current conjugate multiplication weighted average value; The current merged reliability value is used as the previous merged reliability value to iteratively update the current weighting coefficient. In the iterative update of the current weighting coefficient, the target reliability value ranked first is used as the initial merged reliability value; the current merged conjugate multiplication weighted average value is used as the previous merged conjugate multiplication weighted average value to iteratively update the current merged conjugate multiplication weighted average value. In the iterative update of the current merged conjugate multiplication weighted average value, the conjugate multiplication result ranked first is used as the initial merged conjugate multiplication weighted average value, and the last updated current merged conjugate multiplication weighted average value is used as the total merged conjugate multiplication weighted average value.

3. The frequency offset estimation method based on cyclic prefix according to claim 1, characterized in that: The step of dividing the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path includes: According to the time delay of the target path, obtaining a start sampling time point corresponding to the target path within the CP length; The CP length is divided into at least one CP sampling time period according to the start sampling time point, and the CP sampling points in each CP sampling time period are taken as a segmentation set.

4. The frequency offset estimation method based on cyclic prefix according to claim 3, characterized in that: One of the segmentation sets includes at least one of the target paths, each of the target paths includes a respective start sampling time point, and the reliability value of the segmentation set is determined based on the following steps: According to the CP sampling time period, the latest sampling time point of the segmented set is obtained, and according to the time delay of the target path, the target path whose start sampling time point is earlier than the latest sampling time point is used as the signal path of the segmented set, and the target path whose start sampling time point is later than the latest sampling time point is used as the interference path of the segmented set; The reliability value of the segmented set is calculated according to the sum of the powers of the signal paths of the segmented set, the sum of the powers of the interference paths of the segmented set, the number of CP sampling points of the segmented set, and the linear value of the signal-to-noise ratio of the received signal.

5. The frequency offset estimation method based on cyclic prefix according to claim 1, characterized in that: The step of screening the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set includes: Obtaining a comparison value of the segmentation set based on a ratio of the reliability value of the segmentation set to the reliability value of the minimum segmentation set; The comparison values ​​of all the segmentation sets are traversed, and when the comparison value of the segmentation set is greater than the set comparison value, the segmentation set whose comparison value is greater than the set comparison value is removed to obtain the target segmentation set.

6. The frequency offset estimation method based on cyclic prefix according to claim 1, characterized in that: The determining at least one target path according to the multipath distribution and path power of the received signal comprises: Acquire the multipath distribution based on the tracking reference signal to obtain at least one path and the power of at least one path, sort the powers of the paths, and select a set number of paths as the first path according to the sorting result of the powers of the paths from large to small; If the time delay of the included path in the first path is greater than the transcending path of the CP length, all the transcending paths are merged into a total path; At least one target path is obtained based on the total path and the unmerged first path.

7. The frequency offset estimation method based on cyclic prefix according to claim 6, characterized in that: The target path delay is determined based on the following steps: The delays of all transcending paths are combined into a set delay, and the delay of the target path is obtained based on the set delay and the delay of the uncombined target path.

8. The frequency offset estimation method based on cyclic prefix according to claim 2, characterized in that: The target segmentation set includes segmentation sets of different orthogonal frequency division multiplexing OFDM symbols. After the segmentation set is screened according to the reliability value of the segmentation set to obtain the target segmentation set, the method further includes: For the same OFDM symbol, iteratively combine the symbol conjugate multiplication results of the OFDM symbol segmentation set according to the target symbol reliability value of the OFDM symbol segmentation set to obtain a symbol-level combined conjugate multiplication weighted average value and a symbol-level combined reliability value; Based on the symbol-level merging reliability value, iteratively merging the symbol-level merging conjugate multiplication weighted average value again to obtain an updated total merging conjugate multiplication weighted average value; A frequency offset estimation value of the received signal is calculated based on the updated total combined conjugate multiplied weighted average value.

9. A frequency offset estimation device based on cyclic prefix, characterized in that: include: A sampling module, used for performing cyclic prefix CP sampling on the received signal to obtain a CP sampling point set; A determination module, configured to determine at least one target path according to the multipath distribution and path power of the received signal; A segmentation module, configured to divide the CP sampling points in the CP sampling point set into at least one segmentation set according to the CP length of the CP sampling and the delay of the target path; A screening module, used for screening the segmentation set according to the reliability value of the segmentation set to obtain a target segmentation set; A merging module, configured to iteratively merge the conjugate multiplication results of the target segmentation set according to the target reliability value of the target segmentation set to obtain a total merged conjugate multiplication weighted average value; The frequency offset estimation module is used to calculate the frequency offset estimation value of the received signal based on the total combined conjugate weighted multiplication average value.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the frequency offset estimation method based on cyclic prefix according to any one of claims 1 to 8 is implemented.

11. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the frequency offset estimation method based on cyclic prefix as claimed in any one of claims 1 to 8 is implemented.

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