Timing synchronization method and device, electronic equipment and storage medium
By performing multiple sets of PSS sequence correlation detection and SSS sequence correlation detection on the received signal in the LTE system, and selecting the target timing position, the problem of low accuracy of timing synchronization under large frequency bias is solved, and accurate timing synchronization is achieved in ultra-high-speed mobile scenarios.
Patent Information
- Application Number
- CN202311423320.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-27
- Publication Date
- 2025-05-06
AI Technical Summary
In LTE system, the timing synchronization accuracy of the PSS sequence is low, and it cannot effectively solve the Doppler frequency deviation problem caused by ultra-high-speed movement.
By obtaining the received signal and performing correlation detection with local PSS sequences of different packets, multiple sets of half-frame timing positions are determined, and each set of local PSS sequences has a different frequency offset range. Then, the correlation signal is detected by the local SSS sequence, and a target position is selected from multiple sets of half-frame timing positions to perform timing synchronization.
It realizes the accuracy of maintaining timing synchronization under large frequency deviations, can resist any large carrier frequency deviation, and is suitable for high-speed mobile scenarios such as satellite communications.
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Figure CN119945864A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of communication technology, and in particular to a timing synchronization method, device, electronic device and storage medium. Background Art
[0002] In the current LTE (Long Term Evolution, 3GPP Long Term Evolution Plan) system, the physical layer uses the Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS) to complete the cell search. The User Equipment (UE) obtains the Physical Cell Identifier (PCI) and time-frequency synchronization by detecting the PSS and SSS. The PSS sequence has excellent frequency offset resistance, and its frequency offset resistance is half of the LTE subcarrier spacing, that is, ±7.5KHz. However, as the frequency offset increases, that is, when it reaches an integer multiple of the subcarrier spacing, its timing point will be offset. If the Doppler frequency offset caused by high-speed movement is encountered, such as ultra-high-speed scenarios such as satellite communications, the frequency offset can be as high as hundreds of KHZ.
[0003] In the related art, the PSS frequency deviation resistance method includes using a highly stable transceiver crystal oscillator to control the frequency deviation range. This method is a commonly used method, relatively simple, and easy to implement. It retains the excellent performance of PSS in frequency deviation and noise resistance, but increases the hardware cost of the product, and still cannot solve the Doppler effect of large frequency offset caused by ultra-high-speed movement; or, by segmenting the PSS sequence, this method has a limited frequency deviation resistance range (LTE frequency deviation resistance range can be from 7.5KHZ to 20KHZ). Therefore, the timing synchronization accuracy of the related technology is low under large frequency deviation.
[0004] With respect to the above-mentioned problems existing in the related technologies, no effective solutions have been found so far. Summary of the invention
[0005] The present application provides a timing synchronization method, device, electronic device and storage medium to solve the technical problem of low timing synchronization accuracy under large frequency deviation in related technologies.
[0006] According to one aspect of an embodiment of the present application, a timing synchronization method is provided, including: acquiring a received signal; performing correlation detection on the received signal with local PSS sequences of different groups, respectively, to obtain multiple groups of correlation signals, and determining the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein a different frequency deviation range is set for each group of local PSS sequences; performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions; and performing timing synchronization according to the target position.
[0007] According to another aspect of an embodiment of the present application, a timing synchronization device is also provided, including: a receiving module for acquiring a received signal; a PSS detection module for performing correlation detection on the received signal with local PSS sequences of different groups, respectively, to obtain multiple groups of correlation signals, and determining the half-frame timing position of the corresponding local PSS sequence according to each group of correlation signals, wherein a different frequency deviation range is set for each group of local PSS sequences; an SSS detection module for performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions; and a timing module for performing timing synchronization according to the target position.
[0008] Furthermore, the PSS detection module includes a timing unit, which is used to filter the received signal to filter out interference signals other than the frequency occupied by the received PSS sequence in the received signal; perform correlation operations on the filtered received signal with multiple groups of local PSS sequences to obtain multiple groups of first correlation signals; for each group of first correlation signals, extract the first correlation peak with the highest peak value in the first correlation signal; determine the range of N sample points on both sides of the half-frame timing position corresponding to the first correlation peak as the correlation range, where N is a positive integer; use the correlation range to perform correlation operations on the received signal before filtering with multiple groups of local PSS sequences to obtain multiple groups of second correlation signals, for each group of second correlation signals, extract the second correlation peak with the highest peak value in the second correlation signal, and determine the half-frame timing position corresponding to the local PSS sequence according to the second correlation peak.
[0009] Furthermore, the timing unit is also used to normalize the second correlation peak to obtain a third correlation peak; compare the third correlation peak with the correlation peak threshold; if the third correlation peak exceeds the correlation peak threshold, the time corresponding to the third correlation peak is determined as the half-frame timing position corresponding to the local PSS sequence.
[0010] Furthermore, the timing unit is also used to calculate the average power of the received signal; and divide the second correlation peak by the average power to obtain a third correlation peak.
[0011] Furthermore, the SSS detection module also includes a detection unit, which is used to perform time-frequency conversion on the first SSS sequence of the correlation signal at each group of half-frame timing positions to obtain a third SSS sequence in the frequency domain; perform correlation detection on the third SSS sequence and the local SSS sequence, and select a target position from multiple groups of half-frame timing positions based on the detection results.
[0012] Furthermore, the detection unit is also used to start from the first group of half-frame timing positions and execute the following steps in sequence until the last group of half-frame timing positions or the end of detection: perform correlation detection on the third SSS sequence of the current group and the local SSS sequence to determine whether the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection, the half-frame timing position corresponding to the current group is selected as the target position, and the detection is determined to be completed; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a failed detection, the third SSS sequence of the current group is updated to the next group of third SSS sequences in the multiple groups of half-frame timing positions.
[0013] Furthermore, the timing synchronization device also includes a compensation module, which is used to perform least squares channel estimation on the local PSS sequence to obtain an estimated value; and compensate the third SSS sequence based on the estimated value.
[0014] According to another aspect of an embodiment of the present application, a storage medium is further provided, which includes a stored program, and the above steps are executed when the program is run.
[0015] According to another aspect of an embodiment of the present application, there is also provided an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; wherein: the memory is used to store computer programs; and the processor is used to execute the steps in the above method by running the program stored in the memory.
[0016] The embodiment of the present application also provides a computer program product including instructions, which, when executed on a computer, enables the computer to execute the steps in the above method.
[0017] The present application obtains a received signal, performs correlation detection on the received signal with local PSS sequences of different groups, obtains multiple groups of correlation signals, determines the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences sets a different frequency deviation range, performs correlation detection on the correlation signal and the local SSS sequence, selects a target position from the multiple groups of half-frame timing positions, performs timing synchronization according to the target position, performs PSS detection through multiple groups of local PSS sequences with pre-frequency deviations, thereby achieving the purpose of resisting arbitrarily large carrier frequency deviation. The received signal can have an arbitrarily large frequency deviation, and the accuracy of timing synchronization can be maintained in the case of a large frequency deviation. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0019] Figure 1 is a hardware structure block diagram of a computer according to an embodiment of the present application;
[0020] Figure 2 is a flow chart of a timing synchronization method according to an embodiment of the present application;
[0021] Figure 3 It is a schematic diagram of the detection process of resisting arbitrarily large frequency deviation in an embodiment of the present application;
[0022] Figure 4 It is a schematic diagram of a time-frequency two-dimensional detection framework for resisting arbitrarily large frequency deviation in an embodiment of the present application;
[0023] Figure 5 This is a Monte Carlo simulation diagram of an embodiment of the present application;
[0024] Figure 6 It is the radio frame structure of the physical layer in the LTE embodiment of the present application;
[0025] Figure 7 It is a structural block diagram of a timing synchronization device according to an embodiment of the present application. DETAILED DESCRIPTION
[0026] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0028] Example 1
[0029] The method embodiment provided in the first embodiment of the present application can be executed in a mobile phone, a computer, a tablet or a similar computing device. Taking running on a computer as an example, Figure 1 is a hardware structure block diagram of a computer in an embodiment of the present application. Figure 1 As shown, the computer may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data. Optionally, the computer may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above-mentioned computer. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.
[0030] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as a computer program corresponding to a timing synchronization method in an embodiment of the present application. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the computer via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.
[0031] The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the computer. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.
[0032] In this embodiment, a timing synchronization method is provided. Figure 2 is a flow chart of a timing synchronization method according to an embodiment of the present application. Figure 2 As shown, the process includes the following steps:
[0033] Step S10, obtaining a received signal;
[0034] In this embodiment, the downlink synchronization first performs OFDM (Orthogonal Frequency Division Multiplexing) symbol timing through PSS, that is, determines the half-frame (5ms) timing position, and then performs 10ms boundary timing of the basic wireless frame through SSS, that is, timing synchronization is achieved through PSS and SSS.
[0035] The received signal of this embodiment carries a received PSS (Primary Synchronization Signal) sequence and a received SSS (Second Synchronization Signal) sequence used for timing synchronization.
[0036] Step S20, performing correlation detection on the received signal and local PSS sequences of different groups respectively to obtain multiple groups of correlation signals, and determining the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range;
[0037] The received signal is correlated with the local PSS sequences of different groups to obtain multiple groups of correlated signals. For each group of correlated signals, the peak value of the peak of the correlated signal is calculated, and the position corresponding to the peak with the highest peak value is determined as the half-frame timing position of the local PSS sequence corresponding to the group of correlated signals. In this embodiment, the half-frame timing position is a timing position of 5ms.
[0038] In this embodiment, multiple groups of local PSS sequences can be set according to actual needs, and each group of local PSS sequences is set with a different frequency deviation range. In one example, the LTE (Long Term Evolution, 3GPP Long Term Evolution Plan) system can only resist frequency deviation within the range of 7.5KHZ. If the frequency deviation exceeds or far exceeds 7.5KHZ, it will cause a large deviation in the half-frame timing position of PSS detection, thereby causing inaccurate detection results. Therefore, in this embodiment, for example, Figure 4 As shown, multiple groups of local PSS sequences (local PSS0 to local PSSN) within -75KHz to +75KHz are set, and the frequency deviation that can be resisted is expanded from 7.5KHZ to 75KHz. This embodiment can resist any large frequency deviation by adding multiple groups of PSS sequences with pre-frequency deviation for PSS detection. It can be applied to situations where there is a large carrier frequency deviation when (for example, an airplane or a satellite) moves at high speed.
[0039] Step S30, performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions;
[0040] Step S40: performing timing synchronization according to the target position.
[0041] like Figure 4 As shown, the received PSS sequence of the received signal is subjected to PSS correlation detection with multiple groups of local PSS sequences to obtain multiple groups of correlation signals. Each group of correlation signals is subjected to SSS correlation detection with the local SSS sequence. The local SSS sequence is a pseudo-random sequence. Among all the correlation signals, only the target correlation signal with the unique half-frame timing position can pass the SSS detection. Therefore, a target position can be selected from multiple groups of half-frame timing positions through the SSS detection result to complete 10ms timing synchronization.
[0042] Through the above steps, multiple groups of PSS sequences with pre-frequency deviations set according to requirements are used for PSS detection to achieve the purpose of resisting arbitrarily large carrier frequency deviation. The received signal can have arbitrarily large frequency deviation, which can achieve the accuracy of timing synchronization in the case of large frequency deviation.
[0043] In this embodiment, the positions of the PSS sequence and the SSS sequence in the time domain are as follows: Figure 6 As shown, the SSS sequence is located at the last OFDM symbol of the second position slot1 and the twelfth position slot11 of each wireless frame, the PSS is located at the third OFDM symbol of the third position slot2 and the thirteenth position slot12, and the PBCH (Physical Broadcast Channel) is located at the first four OFDM symbols of the second position slot1. In the frequency domain, PSS, SSS and PBCH are all mapped on the 62 subcarriers in the middle excluding DC.
[0044] In one implementation of this embodiment, determining the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals includes:
[0045] S21, filtering the received signal to remove interference signals other than the frequency occupied by the received PSS sequence in the received signal;
[0046] In this embodiment, a received signal with a sampling rate of 7.68 MHz is taken as an example for explanation. The bandwidth occupied by PSS in the received signal is 1.08 MHz. Since only correlation detection needs to be performed on the PSS sequence, only the PSS time domain signal needs to be retained, or a signal larger than the bandwidth occupied by the PSS (for example, a 1.92 MHz signal that is nearly twice the bandwidth occupied by the PSS) can be retained. This can ensure that the spectrum is not distorted and reduce the amount of related calculations. Therefore, in this embodiment, the 7.68 MHz received signal is filtered to eliminate interference signals other than the frequency occupied by the PSS sequence, and the 1.92 MHz signal containing the PSS sequence is retained.
[0047] S22, performing correlation operations on the filtered received signal with multiple groups of local PSS sequences respectively to obtain multiple groups of first correlation signals; for each group of first correlation signals, extracting a first correlation peak with the highest peak value in the first correlation signal;
[0048] The filtered 1.92MHz received signal is correlated with multiple groups of PSS time domain sequences corresponding to the local 1.92MHz to obtain multiple groups of first correlation signals. For each group of first correlation signals, the first correlation peak with the highest peak value in the first correlation signal is extracted, and the time corresponding to the first correlation peak is determined as the initial half-frame timing position, thereby completing the preliminary positioning of the half-frame timing position.
[0049] S23, determining a range of N sample points on both sides of the half-frame timing position corresponding to the first correlation peak as a correlation range, where N is a positive integer;
[0050] S24, using the correlation range to perform correlation operations on the received signal before filtering with multiple groups of local PSS sequences respectively, to obtain multiple groups of second correlation signals, extract the second correlation peak with the highest peak value in each group of second correlation signals, and determine the time corresponding to the second correlation peak as the half-frame timing position corresponding to the local PSS sequence.
[0051] The range within N sample points on both sides of the half-frame timing position corresponding to the first correlation peak is determined as the correlation range, where the N value can be obtained through simulation or experiment. The 7.68MHz received signal before filtering is correlated with multiple groups of PSS time domain sequences corresponding to local 7.68MHz using the correlation range to obtain multiple groups of second correlation signals. For each group of second correlation signals, the second correlation peak with the highest peak value in the second correlation signal is extracted, and the time corresponding to the second correlation peak is determined as the final half-frame timing position, thereby completing the precise positioning of the half-frame timing position.
[0052] In this implementation, the relevant operations are as follows:
[0053]
[0054] Among them, r(n) represents the received signal, s(l) represents the local PSS sequence, * represents the conjugate operation, n represents the discrete time index of the time series, l represents the index of the local PSS sequence, N represents the maximum length of the local PSS sequence, and c(n) represents the correlation peak signal.
[0055] In one implementation of this embodiment, determining the half-frame timing position corresponding to the local PSS sequence according to the second correlation peak includes:
[0056] S241, performing normalization processing on the second correlation peak to obtain a third correlation peak;
[0057] Specifically, the step of normalizing the second correlation peak to obtain the third correlation peak includes: calculating the average power of the received signal; and dividing the second correlation peak by the average power to obtain the third correlation peak.
[0058] The average power of the received signal can be calculated using the following formula: Wherein, r(n) represents the received signal, N represents the number of sample points used to calculate the average power of the received signal r(n), and P represents the average power of the received signal r(n).
[0059] In this implementation, since the size of the received signal is not fixed, it can be any value, for example, the received signal is A, A is any value, and the local PSS sequence correlated with the received signal is a fixed value, such as 1, therefore, the received signal is correlated with the local PSS sequence to obtain a second correlation signal, the second correlation signal includes N second correlation peaks, and the accumulated value of the N second correlation peaks is N*A. In this embodiment, in order to make the correlation peak directly comparable with the theoretical correlation peak threshold, it is necessary to divide the second correlation peak N*A by the average power A to obtain the third correlation peak N, and the third correlation peak N can be compared with the correlation peak threshold.
[0060] S242, performing a comparison operation on the third correlation peak and a correlation peak threshold;
[0061] S243: If the third correlation peak exceeds the correlation peak threshold, determine the time corresponding to the third correlation peak as the half-frame timing position corresponding to the local PSS sequence.
[0062] The second correlation peak is normalized with the average power of the received signal to obtain the third correlation peak, and the third correlation peak is compared with the correlation peak threshold. If the third correlation peak exceeds the correlation peak threshold, synchronization is considered to be completed, and the time corresponding to the third correlation peak is determined as the half-frame timing position corresponding to the local PSS sequence.
[0063] Where r(n) represents the received signal, c(n) represents the correlation peak signal, max is the operation to find the maximum value of the signal, P represents the average power of the received signal r(n), Peak thes represents the theoretical correlation peak threshold, and P_norm represents the correlation peak after power normalization.
[0064] In another implementation of this embodiment, performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions includes:
[0065] S31, performing time-frequency conversion on the first SSS sequence of the correlation signal at each group of half-frame timing positions to obtain a third SSS sequence in the frequency domain;
[0066] S32, performing correlation detection on the third SSS sequence and the local SSS sequence, and selecting a target position from multiple groups of half-frame timing positions based on the detection result.
[0067] After performing multiple groups of PSS detection on the received signal, multiple groups of half-frame timing positions are obtained. Among the multiple groups of half-frame timing positions, only one target position is an accurate timing position, and only the accurate target position can pass the pseudo-random sequence SSS sequence. SSS detection is performed in the frequency domain. Therefore, in this embodiment, the first SSS sequence of the relevant signal at each group of half-frame timing positions is time-frequency converted to obtain a third SSS sequence in the frequency domain. The third SSS sequence is correlated with the local SSS sequence, and a target position is selected from the multiple groups of half-frame timing positions based on the detection result.
[0068] Specifically, performing correlation detection on the third SSS sequence and the local SSS sequence, and selecting a target position from multiple groups of half-frame timing positions based on the detection result includes:
[0069] Starting from the first group of half-frame timing positions, the following steps are performed in sequence until the last group of half-frame timing positions or the end of detection: the third SSS sequence of the current group is correlated with the local SSS sequence to determine whether the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection, the half-frame timing position corresponding to the current group is selected as the target position, and the detection is determined to be completed; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a failed detection, the third SSS sequence of the current group is updated to the next group of third SSS sequences in the multiple groups of half-frame timing positions.
[0070] refer to Figure 3 , perform N groups of PSS detection on the received data to obtain multiple groups of half-frame timing positions, start from the first group of half-frame timing positions, perform correlation detection on the third SSS sequence of the current group and the local SSS sequence, and determine whether the detection result of the third SSS sequence of the current group and the local SSS sequence is passed. If the detection result of the third SSS sequence of the current group and the local SSS sequence is passed, it means that the half-frame timing position corresponding to the current group is the accurate position, then the half-frame timing position corresponding to the current group is selected as the target position, and the detection is determined to be completed; if the detection result of the third SSS sequence of the current group and the local SSS sequence is failed, the third SSS sequence of the current group is updated to the next group of third SSS sequences in the multiple groups of half-frame timing positions, and SSS detection is performed on the next group of half-frame timing positions. If all half-frame timing positions fail the SSS detection, it means that the received signal may be a noise signal, which does not contain PSS sequence and SSS sequence.
[0071] In another implementation of this embodiment, before performing correlation detection on the third SSS sequence and the local SSS sequence, the method further includes: performing least squares channel estimation on the local PSS sequence to obtain an estimated value; and compensating the third SSS sequence based on the estimated value.
[0072] In this implementation, a simple least squares channel estimation is first performed on the local PSS sequence to compensate for the channel interference of the frequency domain data corresponding to the SSS, so that the SSS detection can be performed in a nearly ideal non-interference situation; wherein, the least squares estimation can use LS channel estimation. The SSS sequence is compensated by channel estimation, and then the cell ID and other information are obtained through correlation calculation. The effective peak position of the PSS is determined according to the SSS detection result, thereby obtaining accurate timing synchronization position information.
[0073] In another implementation of this embodiment, the timing synchronization method under large frequency deviation includes:
[0074] First, PSS detection is performed: multiple groups of PSS correlators with pre-frequency offset are used to complete correlation peak detection, and each group completes the output of 5ms timing position. Multiple groups of PSS sequences are used to perform coarse frequency offset estimation. For example, if the receiving end has a large frequency offset received signal of + / -75KHz, the frequency offset is divided into N groups of 10KHz (+ / -5KHz), and each group is subjected to PSS detection;
[0075] Time-frequency conversion: The SSS sequence at the possible timing position is transformed into the frequency domain for secondary detection. After the PSS detection passes, the SSS sequence is obtained according to the timing position for frequency domain conversion;
[0076] LS channel estimation: Perform LS channel estimation on the PSS sequence to obtain the estimated value to compensate the frequency domain SSS sequence and reduce channel and noise interference;
[0077] SSS detection: Use channel estimation to compensate for the SSS sequence, and then obtain information such as the cell ID through correlation calculation;
[0078] Determine effective PSS detection: Determine the effective peak position of PSS based on the SSS detection result, so as to obtain accurate timing synchronization position information. Perform SSS detection on the SSS sequence after channel estimation. If the detection passes, 10ms timing information is obtained. If the detection fails, each group detection result of PSS is traversed and searched until the timing information is detected. If the number of detections exceeds the set threshold, the next frame of data is detected.
[0079] In this embodiment, it is considered that due to the large frequency deviation, the correlation peak detection is inaccurate, that is, the correlation peak detected by PSS may be a pseudo peak. Therefore, this embodiment adds multiple groups of PSS detectors, presets the initial values of possible frequency deviation intervals according to the range of different frequency deviation sizes, performs correlation detection of multiple groups of PSS, and finally determines which group is the real PSS correlation peak through SSS detection in the frequency domain, thereby obtaining an accurate timing position.
[0080] In this embodiment, refer to Figure 5 Taking ±70KHz large frequency deviation as an example, Monte Carlo simulation is performed through Matlab to construct the timing synchronization performance comparison with large frequency deviation and no frequency deviation under different signal-to-noise ratios under ±70KHz frequency deviation and Rayleigh-Gaussian channel. The horizontal axis is the signal-to-noise ratio SNR, and the vertical axis is the right ratio of successful synchronization. As can be seen from the figure, the timing synchronization performance with a large frequency deviation of ±70KHz is basically the same as that without frequency deviation, that is, in the case of frequency deviation, the synchronization performance does not decrease, achieving the purpose of being able to resist the large frequency deviation of ±70KHz and maintaining the accuracy of timing synchronization.
[0081] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present application.
[0082] Example 2
[0083] In this embodiment, a timing synchronization device is also provided to implement the above-mentioned embodiments and preferred implementation modes, which have been described and will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.
[0084] Figure 7 is a structural block diagram of a timing synchronization device according to an embodiment of the present application, such as Figure 7 As shown, the device comprises:
[0085] A receiving module 70, used to obtain a received signal;
[0086] A PSS detection module 71 is used to perform correlation detection on the received signal with local PSS sequences of different groups respectively to obtain multiple groups of correlation signals, and determine the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range;
[0087] An SSS detection module 72, configured to perform correlation detection on the correlation signal and a local SSS sequence, and select a target position from a plurality of groups of half-frame timing positions;
[0088] The timing module 73 is used to perform timing synchronization according to the target position.
[0089] It should be noted that the above modules can be implemented by software or hardware. For the latter, it can be implemented in the following ways, but not limited to: the above modules are all located in the same processor; or the above modules are located in different processors in any combination.
[0090] Example 3
[0091] An embodiment of the present application further provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute the steps of any of the above method embodiments when running.
[0092] Optionally, in this embodiment, the storage medium may be configured to store a computer program for performing the following steps:
[0093] S1, obtain the received signal;
[0094] S2, performing correlation detection on the received signal and local PSS sequences of different groups respectively to obtain multiple groups of correlation signals, and determining the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range;
[0095] S3, performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions;
[0096] S4, performing timing synchronization according to the target position.
[0097] Optionally, in this embodiment, the above-mentioned storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store computer programs.
[0098] An embodiment of the present application further provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.
[0099] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.
[0100] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:
[0101] S1, obtain the received signal;
[0102] S2, performing correlation detection on the received signal and local PSS sequences of different groups respectively to obtain multiple groups of correlation signals, and determining the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range;
[0103] S3, performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the multiple groups of half-frame timing positions;
[0104] S4, performing timing synchronization according to the target position.
[0105] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments and optional implementation modes, and this embodiment will not be described in detail here.
[0106] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0107] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.
[0108] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.
[0109] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
[0110] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.
[0111] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art or all or 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 to enable 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 application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.
[0112] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.
Claims
1. A timing synchronization method, characterized in that: The method comprises: Get the received signal; The received signal is respectively correlated with local PSS sequences of different groups to obtain multiple groups of correlation signals, and the half-frame timing position corresponding to the local PSS sequence is determined according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range; Perform correlation detection on the correlation signal and the local SSS sequence, and select a target position from a plurality of groups of half-frame timing positions; Timing synchronization is performed according to the target position.
2. The method according to claim 1, characterized in that Determining the half-frame timing position of the corresponding local PSS sequence according to each group of correlation signals includes: Performing filtering on the received signal to filter out interference signals other than the frequency occupied by the received PSS sequence in the received signal; The filtered received signal is correlated with multiple groups of local PSS sequences to obtain multiple groups of first correlation signals; for each group of first correlation signals, a first correlation peak with the highest peak value in the first correlation signal is extracted; Determine a range of N sample points on both sides of the half-frame timing position corresponding to the first correlation peak as a correlation range, where N is a positive integer; The correlation range is used to perform correlation operations on the received signal before filtering with multiple groups of local PSS sequences to obtain multiple groups of second correlation signals. For each group of second correlation signals, the second correlation peak with the highest peak value in the second correlation signal is extracted, and the half-frame timing position corresponding to the local PSS sequence is determined according to the second correlation peak.
3. The method according to claim 2, characterized in that Determining the half-frame timing position corresponding to the local PSS sequence according to the second correlation peak includes: performing normalization processing on the second correlation peak to obtain a third correlation peak; Performing a comparison operation on the third correlation peak and the correlation peak threshold; If the third correlation peak exceeds the correlation peak threshold, the time corresponding to the third correlation peak is determined as the half-frame timing position corresponding to the local PSS sequence.
4. The method according to claim 3, characterized in that: The second correlation peak is normalized to obtain a third correlation peak including: Calculating the average power of the received signal; The second correlation peak is divided by the average power to obtain a third correlation peak.
5. The method according to claim 1, characterized in that Performing correlation detection on the correlation signal and the local SSS sequence, and selecting a target position from the plurality of groups of half-frame timing positions comprises: Performing time-frequency conversion on the first SSS sequence of the correlation signal at each group of half-frame timing positions to obtain a third SSS sequence in the frequency domain; The third SSS sequence is correlated with the local SSS sequence and a target position is selected from multiple groups of half-frame timing positions based on the detection result.
6. The method according to claim 5, characterized in that Performing correlation detection on the third SSS sequence and the local SSS sequence, and selecting a target position from multiple groups of half-frame timing positions based on the detection result includes: Starting from the first group of half-frame timing positions, the following steps are performed in sequence until the last group of half-frame timing positions or the end of detection: correlation detection is performed on the third SSS sequence of the current group and the local SSS sequence to determine whether the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a passed detection, the half-frame timing position corresponding to the current group is selected as the target position, and the detection is determined to be completed; if the detection result of the third SSS sequence of the current group and the local SSS sequence is a failed detection, the third SSS sequence of the current group is updated to the next group of third SSS sequences in the multiple groups of half-frame timing positions.
7. The method according to claim 5, characterized in that Before performing correlation detection on the third SSS sequence and the local SSS sequence, the method further includes: Performing least squares channel estimation on the local PSS sequence to obtain an estimated value; The third SSS sequence is compensated based on the estimated value.
8. A timing synchronization device, characterized in that: include: A receiving module, used for acquiring a received signal; A PSS detection module is used to perform correlation detection on the received signal with local PSS sequences of different groups respectively to obtain multiple groups of correlation signals, and determine the half-frame timing position corresponding to the local PSS sequence according to each group of correlation signals, wherein each group of local PSS sequences is set with a different frequency deviation range; An SSS detection module, configured to perform correlation detection on the correlation signal and a local SSS sequence, and select a target position from a plurality of groups of half-frame timing positions; A timing module is used to perform timing synchronization according to the target position.
9. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; wherein: Memory, used to store computer programs; A processor, configured to execute the method steps of any one of claims 1 to 7 by running a program stored in a memory.
10. A storage medium, characterized in that: The storage medium comprises a stored program, wherein the program executes the method steps of any one of claims 1 to 7 when executed.