Time synchronization method, electronic device, and storage medium

Abstract

Embodiments of the present application provide a time synchronization method, an electronic device and a storage medium. The method comprises: segmenting and down-sampling first air interface data to obtain a plurality of groups of primary synchronization signal sequences with the same symbol length; calculating the correlation degrees of the plurality of groups of primary synchronization signal sequences and the first air interface data to obtain coarse synchronization position information with the largest correlation degree with the first air interface data; determining to-be-synchronized data in the first air interface data based on the coarse synchronization position information and a data synchronization length; determining actual secondary synchronization data and a cell ID from the first secondary synchronization data and the second secondary synchronization data; performing frequency offset calculation on the actual secondary synchronization data and the primary synchronization data to obtain frequency offset information; and performing time synchronization according to the frequency offset information and the cell ID. The embodiments of the time synchronization method, the electronic device and the storage medium provided by the present application reduce the amount of data, and the data can be processed in parallel, thereby improving the processing speed and the efficiency and accuracy of subsequent processing and reducing resource consumption.

Description

Technical Field

[0001] This application relates to the field of time synchronization technology, and in particular to a time synchronization method, electronic device and storage medium. Background Technology

[0002] The initial synchronization process of LTE (Long-Term Evolution, 4G wireless communication technology standard) and NR (New Radio) systems involves multiple steps and signals to ensure that the device can detect the cell and achieve time and frequency synchronization.

[0003] Currently, running 4G physical layer (PHY) programs on domestically produced chips faces stringent real-time and computational resource requirements. The 4G LTE standard specifies a series of complex signal processing tasks, including channel estimation, demodulation, and decoding, which need to be completed within strict timing windows.

[0004] In existing technologies, due to the very high real-time requirements of the 4G LTE standard, when it comes to operations with long cycles and large data volumes, such as the processing of broadcast signals (BCH, BCCH), there will be problems of resource shortage and timing constraints. Summary of the Invention

[0005] To address one of the aforementioned technical deficiencies, this application provides a time synchronization method, an electronic device, and a storage medium. The implementation of this application significantly improves synchronization accuracy and efficiency while reducing computational complexity and resource consumption.

[0006] According to a first aspect of the embodiments of this application, a time synchronization method is provided.

[0007] The first air interface data is segmented and downsampled to obtain multiple sets of master synchronization signal sequences with the same symbol length, and adjacent master synchronization signal sequences contain the same symbols.

[0008] Calculate the correlation between each segment of data in multiple sets of master synchronization signal sequences and the first air interface data, and obtain the coarse synchronization position information with the highest correlation to the first air interface data;

[0009] Based on the coarse synchronization location information and the data synchronization length, the data to be synchronized is determined in the first air interface data. The data to be synchronized includes: primary synchronization data, first auxiliary synchronization data and second auxiliary synchronization data.

[0010] The actual auxiliary synchronization data and cell ID are determined from the first auxiliary synchronization data and the second auxiliary synchronization data;

[0011] Frequency offset information is obtained by calculating the frequency offset between the actual auxiliary synchronization data and the primary synchronization data.

[0012] Time synchronization is performed based on frequency offset information and cell ID.

[0013] Optionally, the actual auxiliary synchronization data and cell ID are determined from the first auxiliary synchronization data and the second auxiliary synchronization data, including:

[0014] The first auxiliary synchronization data and the second auxiliary synchronization data are respectively converted into frequency domain data;

[0015] The reverse descrambling results and cell IDs are obtained by performing reverse descrambling calculations on the first and second auxiliary synchronization data in the frequency domain, respectively.

[0016] The larger auxiliary synchronization data in the reverse descrambling result is used as the actual auxiliary synchronization data.

[0017] Optionally, before segmenting and downsampling the first air interface data, the method includes:

[0018] Receive center frequency information sent down from the upper-layer node;

[0019] Based on the center frequency information, the acquired second air interface data is converted into first air interface data corresponding to the frequency of the center frequency information.

[0020] Optionally, the symbol length of the primary synchronization signal sequence is less than the correlation calculation length;

[0021] Accordingly, before calculating the correlation between each segment of data in multiple sets of master synchronization signal sequences and the first air interface data, the method includes:

[0022] Automatic gain control is applied to the master synchronization signal sequence to ensure that the symbol length of the gained master synchronization signal sequence meets the correlation calculation requirements.

[0023] Optionally, the correlation between each segment of data in multiple sets of master synchronization signal sequences and the first air interface data is calculated to obtain the coarse synchronization position information with the highest correlation to the first air interface data, including:

[0024] Multiple sets of master synchronization signal sequences are subjected to conjugate calculations to obtain multiple sets of conjugate symmetric signals.

[0025] By performing sliding correlation calculations on the first air interface data using multiple sets of conjugate symmetric signals, multiple sets of correlation value sequences representing the correlation with the first air interface data are obtained.

[0026] Normalize multiple sets of correlation value sequences to calculate the power value of each segment of data in each correlation value sequence;

[0027] The coarse synchronization position information with the highest correlation to the first air interface data is determined based on the maximum power value.

[0028] Optionally, after normalizing multiple sets of correlation value sequences to calculate the power values ​​of each segment of data in each correlation value sequence, the method includes:

[0029] Check sequentially whether the power value of each data segment is greater than the preset power value;

[0030] If the power values ​​of each data segment are not greater than the preset power value, then the second air interface data will be acquired again.

[0031] If the power value of at least one data segment is greater than the preset power value, then the coarse synchronization position information with the highest correlation to the first air interface data is determined based on the maximum power value.

[0032] Optionally, the data to be synchronized is determined from the first air interface data based on the coarse synchronization location information and the data synchronization length. The method includes:

[0033] Based on the coarse synchronization location information, data synchronization length, and the symbol position of each data in the current communication protocol, the data to be synchronized, including the primary synchronization data, the first auxiliary synchronization data, and the second auxiliary synchronization data, is determined in the first air interface data.

[0034] Optionally, frequency offset information is obtained by calculating the frequency offset between the actual auxiliary synchronization data and the primary synchronization data, including:

[0035] Convert the master synchronization data into frequency domain data;

[0036] Calculate the frequency offset information of the primary synchronization frequency domain data and the actual auxiliary synchronization frequency domain data. The actual auxiliary synchronization frequency domain data is the frequency domain data corresponding to the actual auxiliary synchronization data.

[0037] According to a second aspect of the embodiments of this application, a time synchronization device is provided, comprising:

[0038] Memory;

[0039] Processor; and

[0040] Computer programs;

[0041] The computer program is stored in memory and configured to be executed by the processor to implement the method described above.

[0042] According to a third aspect of the embodiments of this application, a computer-readable storage medium is provided having a computer program stored thereon; the computer program is executed by a processor to implement the method described above.

[0043] Using the time synchronization method, electronic device, and storage medium provided in this application embodiment, the time synchronization method obtains multiple sets of master synchronization signal sequences with the same symbol length by segmenting and downsampling the first air interface data, reducing the data volume while retaining key synchronization information. Furthermore, data can be processed in parallel, improving processing speed and the efficiency and accuracy of subsequent processing, while reducing resource consumption. By determining the coarse synchronization position information through correlation calculation, the initial position of the synchronization signal can be found in a shorter time, improving synchronization accuracy, while avoiding a full-range search throughout the entire data stream, greatly reducing the computational load. Attached Figure Description

[0044] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0045] Figure 1 A schematic diagram of the time synchronization method provided in the embodiments of this application;

[0046] Figure 2 A schematic diagram of the time synchronization device provided in the embodiments of this application. Detailed Implementation

[0047] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0048] Existing technologies, although the 4G LTE standard provides an efficient data transmission mechanism, all PHY layer processing on domestically produced chips must be completed within a specific time window. If the processing time is too long or the amount of data processed is too large, it may lead to packet loss or increased latency, which seriously affects communication quality.

[0049] To address the above problems, this application provides a time synchronization method, such as... Figure 1 As shown, the method includes:

[0050] 100. The first air interface data is segmented and downsampled to obtain multiple sets of master synchronization signal sequences with the same symbol length, and adjacent master synchronization signal sequences contain the same symbols;

[0051] Specifically, air interface data refers to data transmitted through a wireless interface (i.e., the air interface) in a wireless communication system. This data includes control information, user data, and other protocol-related messages. In the embodiments of this specification, the frequency of the first air interface data can be the same as the frequency of the center frequency transmitted by the upper-layer node.

[0052] Specifically, the first air interface data can be segmented in an equal manner, and the adjacent main synchronization signal sequences after segmentation contain the same symbols. The number of adjacent main synchronization signal sequences containing the same symbols is not specifically limited in this embodiment of the specification, but can be set as needed.

[0053] After segmenting the first air interface data, the segmented data can be downsampled sequentially. The downsampling factor can be set as needed, such as 128x downsampling.

[0054] By segmenting and downsampling the first air interface data, multiple sets of master synchronization signal sequences with the same symbol length are obtained, reducing the data volume while retaining key synchronization information. Adjacent master synchronization signal sequences have overlapping symbols, which improves synchronization accuracy because upper-layer nodes can find the same symbols in multiple master synchronization data sequences, thus more accurately determining the starting position of the symbols. Furthermore, by utilizing overlapping symbols in multiple master synchronization data sequences, upper-layer nodes can reduce the probability of synchronization failure due to misinterpretation of a single data segment.

[0055] Specifically, the primary synchronization signal sequence can be the PSS (Primary Synchronization Signal), which occupies 6 RBs (72 sc) of the system bandwidth in the frequency domain. In the LTE system, the PSS sequence is generated based on the Zadoff-Chu sequence. The PSS sequence has three different root sequences, each corresponding to one of the three cell IDs within the cell ID group.

[0056] 200. Calculate the correlation between each segment of data in multiple sets of master synchronization signal sequences and the first air interface data, and obtain the coarse synchronization position information with the highest correlation to the first air interface data;

[0057] Specifically, correlation is used to characterize the degree of synchronization or matching between two signals in time, that is, whether the two signals can keep the same timestamp in time. The higher the correlation, the more consistent the timestamps are.

[0058] Specifically, coarse synchronization location information is approximate location information about the signal arrival time obtained through the initial synchronization process.

[0059] The symbol length of the primary synchronization signal sequence can be less than the correlation calculation length.

[0060] Accordingly, before calculating the correlation between each segment of data in multiple sets of master synchronization signal sequences and the first air interface data, the following may be included:

[0061] Automatic gain control is applied to the master synchronization signal sequence to ensure that the symbol length of the gained master synchronization signal sequence meets the correlation calculation requirements.

[0062] To improve the accuracy of correlation calculation, automatic gain control can be used to increase the symbol length of the master synchronization signal sequence to the required length for correlation calculation. The automatic gain control parameters can be set as needed.

[0063] In an optional embodiment, the method for determining coarse synchronization location information may include:

[0064] Multiple sets of master synchronization signal sequences are subjected to conjugate calculations to obtain multiple sets of conjugate symmetric signals.

[0065] Specifically, conjugate calculations are performed on each master synchronization signal sequence to obtain the conjugate symmetric signal x. i * (k), denoted as:

[0066] x i * (k), k=0,1,…,M-1,i=0,1,2

[0067] Where i is the group number of the conjugate symmetric signal, and M is the length of the symbol.

[0068] By performing sliding correlation calculations on the first air interface data using multiple sets of conjugate symmetric signals, multiple sets of correlation value sequences representing the correlation with the first air interface data are obtained.

[0069] Specifically, the first air interface data y(n) is compared with multiple sets of conjugate symmetric signals x. i * (k) Perform sliding correlation calculations. The correlation calculation formula is:

[0070]

[0071] Where, r i (m) is the cross-correlation value of y(j) and x(j) at time shift m, where m is the time offset, M is the symbol length, and N is the number of samples.

[0072] Normalize multiple sets of correlation value sequences to calculate the power value of each segment of data in each correlation value sequence;

[0073] Specifically, the relevant value r i(m) Normalization yields the relevant value c i (m), to eliminate the influence of signal amplitude, the normalization and power value calculation formula is:

[0074]

[0075] The coarse synchronization position information with the highest correlation to the first air interface data is determined based on the maximum power value.

[0076] Specifically, the coarse synchronization position information may include: sequence information z and first position information p, where sequence information z and first position information p can be determined by the following formula:

[0077]

[0078] Among them, the first location information p is the corresponding timing location, the sequence information z is the local sequence number corresponding to the maximum peak value, and the sequence information z has a corresponding relationship with the physical layer cell ID (NID1), which can be determined by the ZC sequence.

[0079] By using multiple sets of downsampled signals and conjugate calculations, the redundancy of synchronization is increased, improving synchronization accuracy. Sliding correlation calculations and normalization ensure accurate determination of the synchronization point. Furthermore, downsampling significantly reduces the amount of data, lowering computational complexity and processing time. Conjugate calculations simplify correlation calculations, further improving computational efficiency. Simultaneously, multi-level verification and determination of the maximum peak value reduce the probability of missynchronization, ensuring stable system operation even in complex environments.

[0080] In practice, the relevant value c i (m) is often related to the correlation between multiple sets of conjugate symmetric signals and the first air interface data. To avoid wasting computational resources by performing time synchronization when multiple sets of conjugate symmetric signals and the first air interface data do not have a sufficiently strong correlation, the correlation value c can be calculated. i (m) after,

[0081] Check sequentially whether the power value of each data segment is greater than the preset power value;

[0082] If the power values ​​of each data segment are not greater than the preset power value, then the second air interface data will be acquired again.

[0083] If the power value of at least one data segment is greater than the preset power value, then the coarse synchronization position information with the highest correlation to the first air interface data is determined based on the maximum power value.

[0084] Specifically, the preset power value can be a pre-defined threshold used to determine whether the power of a data segment is high enough. Subsequent calculations are only performed when the power value of a data segment exceeds the preset power value. Similarly, if the power values ​​of all data segments are not greater than the preset power value, the second air interface data can be acquired again.

[0085] By determining whether the power value of each data segment is greater than the preset power value, and determining the coarse synchronization position information based on the maximum power value, the synchronization accuracy and reliability of the wireless communication system can be significantly improved.

[0086] 300. Based on the coarse synchronization position information and data synchronization length, the data to be synchronized is determined in the first air interface data. The data to be synchronized includes: primary synchronization data, first auxiliary synchronization data and second auxiliary synchronization data.

[0087] Specifically, the coarse synchronization position information is used to determine the starting position of the data to be synchronized, and the data synchronization length is used to determine the ending position of the data to be synchronized. The data to be synchronized includes at least: primary synchronization data, first auxiliary synchronization data, and second auxiliary synchronization data. Both the first and second auxiliary synchronization data are actual auxiliary synchronization data to be verified.

[0088] In an optional embodiment, the method for determining the data to be synchronized may include:

[0089] Based on the coarse synchronization location information, data synchronization length, and the symbol position of each data in the current communication protocol, the data to be synchronized, including the primary synchronization data, the first auxiliary synchronization data, and the second auxiliary synchronization data, is determined in the first air interface data.

[0090] Specifically, both the first and second auxiliary synchronization data can be Secondary Synchronization Signals. More specifically, the first auxiliary synchronization data can be TDD-SSS, which is transmitted in the first and sixth subframes within a 10ms frame. The second auxiliary synchronization data can be FDD-SSS, which is transmitted in the first subframe within each 10ms frame. The difference lies in their time slots, and consequently, their positions in the first air interface data. The specific positions can be determined according to the communication protocol.

[0091] 400, determine the actual auxiliary synchronization data and cell ID from the first auxiliary synchronization data and the second auxiliary synchronization data;

[0092] Specifically, the actual auxiliary synchronization data is either the first auxiliary synchronization data or the second auxiliary synchronization data. This data is used for time synchronization calculations to determine frequency offset information. It is understood that in LTE and NR communication, either the first or second auxiliary synchronization data can be used for time synchronization. The first and second auxiliary synchronization data are located in different positions within the first air interface data, and the same cell often configures only one communication standard. In practical applications, the actual auxiliary synchronization data representing the cell standard can be determined using the first and second auxiliary synchronization data. The cell ID can be determined using a ZC sequence, and the cell ID can include NID1 (the cell ID within the cell ID group) and NID2 (the cell ID group itself).

[0093] Specifically, the methods for determining the actual auxiliary synchronization data and cell ID may include:

[0094] The first auxiliary synchronization data and the second auxiliary synchronization data are respectively converted into frequency domain data;

[0095] Specifically, the PSS frequency domain signal is used for frequency offset estimation, and the SSS frequency domain signal is used for SSS detection. During the frequency domain data conversion process, the master synchronization data can also be converted.

[0096] For example, the primary synchronization data (pss_filter_out), the first auxiliary synchronization data (sss_tddfilter_out), and the second auxiliary synchronization data (sss_fdd_filter_out) can be taken as input sequentially. Based on the position PSS_POS_Second estimated by the fine synchronization, time-domain symbols (frequency-domain data) of PSS, SSS-TDD, and SSS-FDD with a symbol length of 2192 can be extracted. The CP (cyclic prefix) is removed from the time-domain symbols of PSS, FDD-SSS, and TDD-SSS respectively, and a 2048-point FFT is performed to obtain the frequency-domain data. 31 REs ([994:10241026:1056]) before and after the center frequency point (excluding the DC position) are concatenated into frequency-domain data with a length of 62.

[0097] Inverse descrambling calculations are performed on the first and second auxiliary synchronization data in the frequency domain, respectively;

[0098] The larger auxiliary synchronization data in the reverse descrambling result is used as the actual auxiliary synchronization data.

[0099] Specifically, since the PSS (Pressure Sequence Signal) of two consecutive half-frames within a single frame is exactly the same, PSS synchronization can only determine 5ms of timing. In contrast, SSS (Signal Sequence Signal) is a different signal between consecutive half-frames; detecting just one SSS is enough to determine the current subframe index, achieving downlink synchronization with 10ms timing. Furthermore, SSS sequence detection can be performed in either the time or frequency domain. Time-domain correlation detection requires correlation detection of all 2048 values ​​of the entire OFDM symbol, resulting in high computational complexity and susceptibility to timing estimation errors. Frequency-domain detection, on the other hand, only requires extracting 62 points of the received SSS sequence for correlation, reducing computational complexity. Moreover, timing synchronization errors have little impact on the correlation peak in the frequency domain; therefore, SSS sequence detection is performed in the frequency domain.

[0100] Based on the generation rules of the SSS sequence, NID1, the system subframe number (0ms / 5ms), and the cell standard LTE-FDD / LTE-TDD can be determined by reverse descrambling. The extracted frequency domain FDD-SSS and TDD-SSS signals are reverse descrambled to obtain {m_tdd,m0_tdd,m1_tdd} and {m_fdd,m0_fdd,m1_fdd}, respectively. Furthermore, the cell standard is determined by comparing m_tdd and m_fdd, the current subframe index is determined by comparing the corresponding m0 and m1, and NID1 is calculated.

[0101] Specifically, taking the reverse descrambling of the second auxiliary synchronization data FDD-SSS as an example, the specific algorithm flow is described as follows:

[0102] SSS frequency domain signal reverse descrambling:

[0103] ① The FDD-SSS signal is transmitted on 62 subcarriers, which can be divided into odd and even subcarriers. First, the FDD-SSS signal is divided into d(2n) and d(2n+1) according to the odd and even subcarriers, where n = 0, 1, ..., 30. Two local descrambling sequences s0 and s1 are generated based on NID1 (cell ID within cell ID group) and NID2 (cell ID group); based on NID2, the sequence m(n) is cyclically shifted to generate sequences c0(n) and c1(n).

[0104] ②The descrambled dual sequence is obtained by descrambling the dual sequence d(2n) using c0(n).

[0105]

[0106] ③ Use the local descrambling sequence s(n) and the descrambling pair sequence Perform a cyclic cross-correlation operation to find the peak value, which is the estimated value of m0_fdd.

[0107]

[0108] where \(k\) is the time shift amount, and \(k = 0, 1, \cdots, 30\).

[0109] ④ Cyclically shift the local descrambling sequence \(z(n)\) based on \(m0\_fdd\) to obtain For odd sequence descrambling:

[0110]

[0111] ⑤ Use \(c1(n)\) and descramble the sequence \(d(2n + 1)\) to obtain the descrambling odd sequence

[0112]

[0113] ⑥ Perform a cyclic cross - correlation operation between the local descrambling sequence \(s(n)\) and the descrambling odd sequence to find the peak value, and this peak value is the estimated value of \(m1\_fdd\):

[0114]

[0115] where \(k\) is the time shift amount, and \(k = 0, 1, \cdots, 30\).

[0116] ⑦ Average \(m0\_fdd\) and \(m1\_fdd\) to obtain the base sequence \(m\_fdd\);

[0117] \(m\_fdd=(m0\_fdd + m1\_fdd) / 2\)

[0118] Similarly, \(m\_tdd\), \(m0\_tdd\), and \(m1\_tdd\) can be obtained.

[0119] Cell mode determination

[0120] Determine the cell mode by comparing \(m\_tdd\) and \(m\_fdd\). Specifically:

[0121] ① If \(m\_tdd>m\_fdd\), the cell is LTE - TDD; meanwhile, \(m0 = m0\_tdd\), \(m1 = m1\_tdd\);

[0122] ② Otherwise, the cell is LTE - FDD; meanwhile, \(m0 = m0\_fdd\), \(m1 = m1\_fdd\).

[0123] Sub - frame index determination

[0124] Regardless of whether the system is LTE - FDD or LTE - TDD, the sub - frame index positions of the SSS are only two: 0 and 5. Determine the sub - frame index by comparing \(m0\) and \(m1\). Specifically:

[0125] ① If \(m0<m1\), the sub - frame index is 0, and meanwhile the estimated value of \(m0\) The estimated value

[0126]

[0127] Otherwise, the subframe index is 5, and at the same time

[0128] By converting auxiliary synchronization data into frequency domain data, frequency domain processing can be performed more accurately, improving synchronization precision. Reverse descrambling allows the original auxiliary synchronization data to be recovered, ensuring data accuracy and reducing synchronization failures caused by misjudgments in single detections. Furthermore, reverse descrambling eliminates interference introduced by descrambling, improving signal clarity and enabling symbol timing and carrier frequency synchronization to be completed quickly, thus improving system response speed.

[0129] 500, frequency offset information is obtained by calculating the frequency offset of the actual auxiliary synchronization data and the primary synchronization data.

[0130] Specifically, frequency offset information characterizes the frequency deviation between LTE and NR. Frequency offset information can be estimated by calculating the phase difference between the actual auxiliary synchronization data and the primary synchronization data.

[0131] Specifically, methods for determining frequency offset information may include:

[0132] Convert the master synchronization data into frequency domain data;

[0133] Calculate the frequency offset information of the primary synchronization frequency domain data and the actual auxiliary synchronization frequency domain data. The actual auxiliary synchronization frequency domain data is the frequency domain data corresponding to the actual auxiliary synchronization data.

[0134] In the specific implementation process, the actual auxiliary synchronization frequency domain data can be multiplied in the time domain.

[0135] η*(o) is frequency-shifted to obtain the second actual auxiliary synchronization frequency domain data.

[0136]

[0137] Assume the frequency shift range is: [-b:Δ:b];

[0138]

[0139] Where η*(o) is the original time-domain signal, The frequency offset to be removed is given by f, where b is the maximum frequency offset to be attempted, and Δ is the attempt step size; s The sampling rate of the ADC.

[0140] Specifically, the second actual auxiliary synchronization frequency domain data Performing related operations with the master synchronization data 'a' can be done through relevant formulas, specifically the related value sequence θ. e The formula for calculating (s) is:

[0141]

[0142] For the correlation value sequence θ e (s) is normalized to calculate each θ e The power value of (s);

[0143] Specifically, for θ e Normalization of (s) can be performed using the following formula.

[0144]

[0145] Where, λ e (s) is θ e The power value of (s).

[0146] Based on θ e The maximum power value in (s) is used to obtain the frequency offset information and second position information that have the greatest correlation with the time domain signal.

[0147] Specifically, the position of the maximum peak ξ and the frequency offset information κ are selected.

[0148]

[0149] The embodiments in this specification improve synchronization accuracy, reduce misjudgments, enhance anti-interference capabilities, simplify synchronization algorithms, and support fast synchronization by calculating the frequency offset information of the primary synchronization frequency domain data and the actual auxiliary synchronization frequency domain data.

[0150] 600, time synchronization is performed based on frequency offset information and cell ID;

[0151] Specifically, frequency offset information and cell ID can be sent to the connected upper-layer nodes so that the upper-layer nodes can perform time synchronization based on the frequency offset information and cell ID.

[0152] The time synchronization method provided in this embodiment obtains multiple master synchronization signal sequences with the same symbol length by segmenting and downsampling the first air interface data, reducing the data volume while retaining key synchronization information. Furthermore, the data can be processed in parallel, improving processing speed and the efficiency and accuracy of subsequent processing, while reducing resource consumption. By determining the coarse synchronization position information through correlation calculation, the initial position of the synchronization signal can be found in a shorter time, improving synchronization accuracy. At the same time, it avoids a full-range search throughout the entire data stream, greatly reducing the computational load.

[0153] In one embodiment of this specification, prior to segmenting and downsampling the first air interface data as described above, the method may include:

[0154] Receive center frequency information sent down from the upper-layer node;

[0155] Specifically, the upper-level node can be Operation Administration and Maintenance. The center frequency refers to the center frequency of the signal spectrum, that is, the middle frequency of the signal bandwidth. It should be noted that in communication systems, the center frequency usually refers to the carrier frequency. The center frequency is used to determine the signal's position in the frequency domain.

[0156] Based on the center frequency information, the acquired second air interface data is converted into first air interface data corresponding to the frequency of the center frequency information.

[0157] Specifically, second air interface data refers to raw data received from the wireless interface, which is typically received at an initial center frequency or an uncalibrated center frequency.

[0158] For example, the frequency of the second air interface data transmitted via the wireless interface (i.e., the air interface) is 128 GHz, with a center frequency of 2.6 GHz. In practical use, the second air interface data at a frequency of 128 GHz can be modulated into first air interface data at a frequency of 2.6 GHz.

[0159] The implementation of the embodiments in this specification can improve spectrum utilization and system transmission efficiency. It is understood that there can be multiple wireless interfaces, and correspondingly, different wireless interfaces can be configured with different center frequencies. Through reasonable frequency planning and center frequency settings, interference between adjacent cells can be reduced, and system reliability can be improved.

[0160] Using the time synchronization method, electronic device, and storage medium provided in this application embodiment, the time synchronization method obtains multiple sets of master synchronization signal sequences with the same symbol length by segmenting and downsampling the first air interface data, reducing the data volume while retaining key synchronization information. Furthermore, data can be processed in parallel, improving processing speed and the efficiency and accuracy of subsequent processing, while reducing resource consumption. By determining the coarse synchronization position information through correlation calculation, the initial position of the synchronization signal can be found in a shorter time, improving synchronization accuracy, while avoiding a full-range search throughout the entire data stream, greatly reducing the computational load.

[0161] In addition to time synchronization, satellite communication systems also require symbol synchronization, such as symbol synchronization of the aforementioned master synchronization signal. The synchronization process is as follows:

[0162] The main synchronization signal is acquired and segmented to obtain multiple sub-signals to be processed.

[0163] For each target sub-signal among the plurality of sub-signals to be processed, the first sample value and the second sample value corresponding to the current sampling point in the target sub-signal are multiplied by conjugate to obtain the clock error value of the target sub-signal; the second sample value represents the difference between the sample values ​​of two adjacent sampling points of the current sampling point;

[0164] The clock error value is corrected, and the sampling clock deviation of the target sub-signal is determined based on the corrected clock error value;

[0165] Based on the sampling clock deviation, the target sub-signal is interpolated and filtered to obtain the target signal after symbol synchronization processing of each of the sub-signals to be processed.

[0166] In one optional embodiment of this application, the segmentation of the main synchronization signal to obtain multiple sub-signals to be processed includes:

[0167] Obtain the total data length of the master synchronization signal;

[0168] The main synchronization signal is segmented into segments of equal length according to a preset data length to obtain multiple initial sub-signals to be processed.

[0169] If the data length of the last initial sub-signal to be processed is less than the preset data length based on the total data length, then the last initial sub-signal to be processed is padded with data so that the data length of the last initial sub-signal to be processed after data padding is equal to the preset data length, thus obtaining the plurality of sub-signals to be processed; or, if the data length of the last initial sub-signal to be processed is equal to the preset data length based on the total data length, then the plurality of initial sub-signals to be processed are determined as the plurality of sub-signals to be processed.

[0170] In one optional embodiment of this application, the master synchronization signal is a signal of a superframe structure, which consists of a header protection symbol, a tail protection symbol, a superframe start (SOSF), a superframe format indicator (SFFI), a superframe header (SFH), a physical layer frame (PLF), and pilot signals.

[0171] In an optional embodiment of this application, the error correction of the clock error value includes:

[0172] Obtain the roll-off factor and signal-to-noise ratio of the raised cosine roll-off RRC filter, and determine the compensation factor for the clock error value based on the roll-off factor and the signal-to-noise ratio;

[0173] The clock error value of the target sub-signal is normalized.

[0174] Based on the compensation factor, the clock error value after normalization is corrected to obtain the corrected clock error value of the target sub-signal.

[0175] In one optional embodiment of this application, determining the sampling clock offset of the target sub-signal based on the corrected clock error value includes:

[0176] Determine the preset fitting order, and determine the fitting factor for each fitting order in the preset fitting order;

[0177] Based on the fitting factors of each fitting order, a polynomial fitting function for the corrected clock error value at the preset fitting order is constructed to obtain the sampling clock deviation of the target sub-signal.

[0178] The process involves interpolating and filtering the target sub-signals based on the sampling clock offset to obtain the target signal after symbol synchronization processing of each of the sub-signals to be processed, including:

[0179] Data is filled before the start sampling point and after the end sampling point in the target sub-signal to obtain the data-filled target sub-signal.

[0180] Based on the target sub-signal after data filling and the pre-configured first interpolation coefficients, the second interpolation coefficients are determined; the first interpolation coefficients are a matrix vector of the preset fitting order.

[0181] Based on the second interpolation coefficient, an interpolation filtering operation is performed on the sampling clock deviation of the target sub-signal to obtain the target signal after symbol synchronization processing of each of the sub-signals to be processed.

[0182] In an optional embodiment of this application, the method further includes:

[0183] Based on the current sampling point at the location of the pilot in the target sub-signal and at least one adjacent sampling point of the current sampling point, at least two pilot data sequences of the target sub-signal are determined.

[0184] The at least two pilot data sequences are respectively correlated with the local pilot data sequence to obtain the cross-correlation value between the at least two pilot data sequences of the target sub-signal and the local pilot data sequence;

[0185] The correlation power value of the target sub-signal is determined based on the cross-correlation values ​​between the at least two pilot data sequences and the local pilot data sequence.

[0186] In one optional embodiment of this application, the master synchronization signal is a digital signal with a symbol rate of 2.

[0187] Those skilled in the art will understand that embodiments of this application can be provided as methods or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as C, VHDL, Verilog, the object-oriented programming language Java, and the interpreted scripting language JavaScript.

[0188] This application is described with reference to flowchart illustrations and / or block diagrams of methods and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0189] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0190] These computer program instructions can also be loaded onto a computer or other programmable data processing equipment, such as Figure 2 As shown, this causes a series of operational steps to be performed on a computer or other programmable device to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable device for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0191] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0192] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0193] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0194] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0195] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A time synchronization method, characterized in that, include: Receive center frequency information sent down from the upper-layer node; where center frequency refers to the center frequency of the signal spectrum. Based on the center frequency information, the acquired second air interface data is converted into first air interface data corresponding to the frequency of the center frequency information; wherein, the second air interface data refers to the raw data received from the wireless interface; The first air interface data is segmented and downsampled to obtain multiple sets of main synchronization signal sequences with the same symbol length, and adjacent main synchronization signal sequences contain the same symbols; Calculating the correlation between each data segment in the multiple sets of primary synchronization signal sequences and the first air interface data to obtain the coarse synchronization position information with the highest correlation to the first air interface data includes: performing conjugate calculations on the multiple sets of primary synchronization signal sequences to obtain multiple sets of conjugate symmetric signals; performing sliding correlation calculations on the first air interface data using the multiple sets of conjugate symmetric signals to obtain multiple sets of correlation value sequences representing the correlation with the first air interface data; normalizing the multiple sets of correlation value sequences to calculate the power value of each data segment in each correlation value sequence; sequentially determining whether the power value of each data segment is greater than a preset power value; if the power value of each data segment is not greater than the preset power value, then reacquiring the second air interface data; if the power value of at least one data segment is greater than the preset power value, then determining the coarse synchronization position information with the highest correlation to the first air interface data based on the largest power value. Based on the coarse synchronization location information, data synchronization length, and symbol positions of various data in the current communication protocol, data to be synchronized, including primary synchronization data, first auxiliary synchronization data, and second auxiliary synchronization data, are determined in the first air interface data. The first auxiliary synchronization data and the second auxiliary synchronization data are located in different positions in the first air interface data, and the same cell is configured with one communication standard. If the first auxiliary synchronization data is TDD-SSS, it is transmitted in the 1st and 6th subframes within a 10 ms frame. If the first auxiliary synchronization data is FDD-SSS, it is transmitted in the 1st subframe within a 10 ms frame. The actual auxiliary synchronization data and cell ID are determined from the first auxiliary synchronization data and the second auxiliary synchronization data, including: converting the first auxiliary synchronization data and the second auxiliary synchronization data into frequency domain data, including: taking the primary synchronization data, the first auxiliary synchronization data, and the second auxiliary synchronization data as input in sequence, extracting PSS, SSS-TDD, and SSS-FDD time domain symbols with a symbol length of 2192 according to the position PSS_POS_Second of the fine synchronization estimate; removing the cyclic prefix from the time domain symbols of PSS, FDD-SSS, and TDD-SSS respectively, and performing a 2048-point FFT to obtain frequency domain data; and taking 31 resource elements before and after the center frequency point respectively and concatenating them into frequency domain data with a length of 62. Reverse descrambling calculations are performed on the first and second auxiliary synchronization data in the frequency domain to obtain the reverse descrambling result and cell ID, including: The steps for reverse descrambling of SSS frequency domain signals include: The FDD-SSS signal is transmitted on 62 subcarriers; these subcarriers are divided into odd-numbered and even-numbered subcarriers; the FDD-SSS signal is further divided into d(2n) and d(2n+1) according to the odd-even subcarrier configuration, where n = 0, 1, ..., 30; two local descrambling sequences are generated based on NID1 and NID2. and Generate by cyclic shifting sequence m(n) based on NID2 and ; use The dual sequence d(2n) is descrambled to obtain : ； Using the local descrambling sequence s(n) and the descrambling couple sequence Perform cyclic cross-correlation to find the peak value, which is the estimated value of m0_fdd. ； Where k is the time shift, k=0,1...30; Based on the cyclic shift of the local descrambled sequence z(n) using m0_fdd, we obtain Used for descrambling odd sequences: ； use and Descrambling the sequence d(2n+1) yields the descrambled odd sequence. ; ； Using the local descrambling sequence s(n) and the descrambling odd sequence Perform cyclic cross-correlation to find the peak value, which is the estimated value of m1_fdd. ； Where k is the time shift, k=0,1.….,30; The base sequence m_fdd is obtained by averaging m0_fdd and m1_fdd. ； And so on, we get m_tdd, m0_tdd, m1_tdd; The process of determining the cell network type includes: If m_tdd > mfdd, the cell supports LTE-TDD; simultaneously =m0_tdd, =m1_tdd; Otherwise, the cell is LTE-FDD; at the same time =m0_fdd, =m1_fdd; if < The subframe index is 0, and at the same time -1, -1; otherwise, the subframe index is 5, and... -1, -1; The larger auxiliary synchronization data in the reverse descrambling result is used as the actual auxiliary synchronization data. Frequency offset information is obtained by calculating the frequency offset of the actual auxiliary synchronization data and the primary synchronization data, including: converting the primary synchronization data into primary synchronization frequency domain data; calculating the frequency offset information of the primary synchronization frequency domain data and the actual auxiliary synchronization frequency domain data, wherein the actual auxiliary synchronization frequency domain data is the frequency domain data corresponding to the actual auxiliary synchronization data; wherein the actual auxiliary synchronization frequency domain data is calculated by time domain multiplication. Frequency shifting is performed to obtain the second actual auxiliary synchronization frequency domain data. : ， Assume the frequency shift range is: ; ； in, This is the original time-domain signal. Frequency offset to be removed ; The sampling rate of the ADC; The second actual auxiliary synchronization frequency domain data Perform related operations with the master synchronized data 'a', and obtain the related value sequence. The calculation formula is: ； right Normalization is performed to calculate each The power value; right Normalization is performed using the following formula: ； for The power value; based on The maximum power value in the time domain is used to obtain the frequency offset information and the second position information that are most correlated with the time domain signal; Select the position of the maximum peak and frequency offset information : ； Time synchronization based on the frequency offset information and the cell ID includes: sending the frequency offset information and the cell ID to the connected upper-layer node so that the upper-layer node can perform time synchronization based on the frequency offset information and the cell ID.

2. The time synchronization method according to claim 1, characterized in that, The symbol length of the main synchronization signal sequence is less than the correlation calculation length; Accordingly, before calculating the correlation between each segment of data in the multiple sets of master synchronization signal sequences and the first air interface data, the method includes: Automatic gain control is applied to the master synchronization signal sequence so that the symbol length of the gained master synchronization signal sequence meets the correlation calculation requirements.

3. The time synchronization method according to claim 1, characterized in that, The step of calculating the frequency offset information by performing frequency offset calculation on the actual auxiliary synchronization data and the primary synchronization data includes: The master synchronization data is converted into frequency domain data, which is the master synchronization frequency domain data. Calculate the frequency offset information of the primary synchronization frequency domain data and the actual auxiliary synchronization frequency domain data, wherein the actual auxiliary synchronization frequency domain data is the frequency domain data corresponding to the actual auxiliary synchronization data.

4. An electronic device, characterized in that, include: Memory; processor; as well as Computer programs; The computer program is stored in the memory and configured to be executed by the processor to implement the method as described in any one of claims 1-3.

5. A computer-readable storage medium, characterized in that, It stores a computer program thereon; the computer program is executed by a processor to implement the method as described in any one of claims 1-3.

Images