Cell search method, cell search device, electronic device, and storage medium

Abstract

This disclosure relates to the field of signal processing technology, specifically to a cell search method, a cell search device, an electronic device, and a storage medium. The cell search method applied to an electronic device includes: receiving a baseband signal continuously transmitted by a base station; determining the current correlation value between the baseband signal and a local target primary synchronization signal sequence; determining the historical correlation value corresponding to a first number of historical sampling points closest to the current time based on a first sampling frequency; if the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value, then determining the target sampling point as a valid sampling point, and performing secondary synchronization signal detection based on the baseband signal corresponding to the target sampling point to obtain a signal detection result; and establishing a network connection with the base station based on the signal detection result. This method can avoid sidelobe false peak interference, significantly reduce invalid detection actions, and lower the power consumption of the electronic device.

Description

Technical Field

[0001] This disclosure relates to the field of signal processing technology, specifically to a cell search method, a cell search device, an electronic device, and a computer-readable storage medium. Background Technology

[0002] With the development of technology, digital baseband cell search technology has been widely used in Long Term Evolution (LTE) systems. During cell search and Primary Synchronization Signal (PSS) detection by electronic devices, the baseband signal is susceptible to signal autocorrelation sidelobe effects, multipath fading, and noise interference, which can generate a large number of dense spurious correlation peaks near the actual PSS timing point, leading to cell search failure or increased search latency for electronic devices. Summary of the Invention

[0003] To overcome the problems existing in related technologies, an exemplary embodiment of this disclosure provides a cell search method applied to an electronic device. The method includes: receiving a baseband signal continuously transmitted by a base station; determining the current correlation value between the baseband signal and a local target primary synchronization signal sequence; determining the historical correlation value corresponding to a first number of historical sampling points closest to the current time according to a first sampling frequency, wherein the sampling points correspond one-to-one with the receiving time; if the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value, then determining the target sampling point as a valid sampling point, and performing secondary synchronization signal detection based on the baseband signal corresponding to the target sampling point to obtain a signal detection result, wherein the target sampling point is spaced between the current time and a second number of sampling intervals; and establishing a network connection with the base station based on the signal detection result.

[0004] In some embodiments, the local target master synchronization signal sequence includes: a third number of local cyclic prefix sampling points and a fourth number of local master synchronization signal sampling points, wherein the third number of local cyclic prefix sampling points are truncated from the end of the local original master synchronization signal sequence, and the fourth number of local master synchronization signal sampling points are the remaining sampling points of the local original master synchronization signal sequence, and the sum of the third number and the fourth number is equal to the total number of sampling points of the local original master synchronization signal sequence.

[0005] In some embodiments, the third quantity is determined based on the minimum sampling interval between adjacent target sampling points, which is determined based on the difference between the first quantity and the second quantity.

[0006] In some embodiments, auxiliary synchronization signal detection is performed based on the baseband signal corresponding to the target sampling point to obtain a signal detection result, including: determining a second sampling rate corresponding to the auxiliary synchronization signal detection according to a first sampling frequency and a third quantity; sampling the baseband signal according to the second sampling rate to determine the number of sampling points of the base station cyclic prefix in the baseband signal; determining an anti-timing deviation margin window according to the third quantity and the number of sampling points of the base station cyclic prefix, wherein the left endpoint of the anti-timing deviation margin window is the difference between the third quantity and the number of sampling points of the base station cyclic prefix, and the right endpoint of the anti-timing deviation margin window is the third quantity; and performing auxiliary synchronization signal detection on the baseband signal corresponding to the target sampling point within the anti-timing deviation margin window to obtain a signal detection result.

[0007] In some embodiments, determining the historical correlation value corresponding to the first number of historical sampling points closest to the current time according to the first sampling frequency includes: obtaining the historical correlation value corresponding to the first number of historical sampling points closest to the current time through a sliding observation window according to the first sampling frequency, wherein the sliding observation window is used to simultaneously observe the historical correlation value corresponding to the first number of historical sampling points and the current correlation value corresponding to the current time, and the total number of observations of sampling points in the sliding observation window is equal to the first number plus 1.

[0008] In some embodiments, the target sampling point is located in the middle area of ​​the sliding observation window, and the ratio of the second number to the total number of observations is less than or equal to 1 / 2, and the second number is greater than or equal to 2.

[0009] In some embodiments, the method further includes: if the historical correlation value corresponding to the target sampling point is not the absolute maximum value among all historical correlation values ​​and the current correlation value, then the target sampling point is determined to be an invalid sampling point, and the step of receiving the baseband signal continuously transmitted by the base station is re-executed at the next receiving time, wherein the next receiving time is separated from the current time by a sampling interval.

[0010] Secondly, this disclosure also provides a cell search device deployed in an electronic device, comprising: a receiving module for receiving baseband signals continuously transmitted by a base station; a first processing module for determining the current correlation value between the baseband signal and a local target primary synchronization signal sequence; a second processing module for determining, according to a first sampling frequency, the historical correlation value corresponding to a first number of historical sampling points closest to the current time, wherein the sampling points correspond one-to-one with the receiving time; a third processing module for determining the target sampling point as a valid sampling point if the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value, and performing secondary synchronization signal detection based on the baseband signal corresponding to the target sampling point to obtain a signal detection result, wherein the receiving time corresponding to the target sampling point is spaced between the current time and a second number of sampling intervals; and a connection module for establishing a network connection with the base station based on the signal detection result.

[0011] Thirdly, this disclosure also provides an electronic device, including: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor performs the cell search method provided in any of the above aspects by executing the computer instructions.

[0012] Fourthly, this disclosure also provides a computer-readable storage medium storing a program for performing the cell search method provided in any of the foregoing aspects.

[0013] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure.

[0014] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: According to the cell search method provided by this disclosure, after determining the current correlation value between the baseband signal received at the current time and the local target primary synchronization signal sequence, the electronic device combines the historical correlation values ​​corresponding to the nearest first number of historical sampling points to comprehensively analyze the synchronization change trend of the baseband signal, thereby achieving effective screening of the true primary synchronization peak. Furthermore, when determining the baseband signal used for secondary synchronization signal detection, the determination is based on whether the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value. This not only avoids interference from sidelobe false peaks caused by noise and multipath fading but also improves the determination efficiency and ensures the timely triggering of secondary synchronization signal detection. Moreover, establishing a network connection with the base station based on the signal detection result of secondary synchronization signal detection can significantly reduce invalid detection actions while ensuring the reliability of cell search, effectively reducing the power consumption of the electronic device and extending the device's battery life. Attached Figure Description

[0015] This disclosure can be better understood by describing exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, in which: Figure 1 This is a flowchart illustrating a cell search method according to an exemplary embodiment of a published document; Figure 2 This is a schematic diagram illustrating the structure of a local target master synchronization signal sequence according to an exemplary embodiment of the present disclosure; Figure 3 This is a flowchart illustrating another cell search method according to an exemplary embodiment of the present disclosure; Figure 4 This is a schematic diagram illustrating the principle of implementing frequency reduction processing according to an exemplary embodiment of the present disclosure; Figure 5This is a schematic diagram of the structure of a cell search device according to an exemplary embodiment of the present disclosure; Figure 6 This is a schematic diagram of the structure of an electronic device according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0016] The following describes specific embodiments of this disclosure. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this disclosure, changes in design, manufacturing, or production based on the technical content disclosed in this disclosure are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0017] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “a” or “one,” etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising,” “including,” etc., mean that the element or object preceding “comprising” or “including” encompasses the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected,” “linked,” etc., are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0018] With the development of technology, digital baseband cell search technology has been widely used in Long Term Evolution (LTE) systems. During cell search and Primary Synchronization Signal (PSS) detection by electronic devices, the baseband signal is susceptible to signal autocorrelation sidelobe effects, multipath fading, and noise interference, which can generate a large number of dense spurious correlation peaks near the actual PSS timing point, leading to cell search failure or increased search latency for electronic devices.

[0019] For example, taking a mobile phone as an example, when a mobile phone searches for nearby base stations using LTE technology, it continuously receives baseband signals transmitted by the base stations and determines the matching relationship between these signals and the local PSS sequence. Only when a genuine PSS signal in the baseband signal is successfully detected can the mobile phone complete the network connection with the base station. However, if the baseband signal is mixed with noise and false PSS signals, the mobile phone may misjudge its synchronization position, ultimately leading to cell search failure or increased search latency.

[0020] In related technologies, the main approach is to filter genuine PSS signals using a combination of fixed threshold decision and forced downsampling. Specifically, sampling points with correlation exceeding a preset fixed threshold or adaptive threshold are marked as candidate synchronization points. Dense trigger sampling points are then extracted at fixed intervals. Finally, the filtered timing points are sent to the Secondary Synchronization Signal (SSS) detection module, and a Fast Fourier Transform (FFT) window is activated for signal demodulation. However, spurious sidelobe peaks around the genuine peak frequently trigger subsequent SSS detection modules, leading to increased dynamic power consumption and heavier hardware load. Furthermore, forced downsampling introduces uncontrollable timing quantization deviations, resulting in inter-symbol interference (ISI), which significantly degrades SSS demodulation performance and, in severe cases, directly causes cell search failure.

[0021] To address the aforementioned problems, this disclosure provides a cell search method applied to electronic devices. These electronic devices may include, but are not limited to, mobile phones, tablets, laptops, or other devices with network connectivity. Figure 1 As shown, the cell search method may include the following steps: Step S110: Receive the baseband signal continuously transmitted by the base station.

[0022] During cell search, electronic devices continuously receive baseband signals transmitted by the base station. By comparing these baseband signals with the electronic device's local target master synchronization signal sequence, they determine whether a network connection can be established with the base station. These baseband signals can be understood as the signals received by the electronic device at the current moment during base station streaming.

[0023] Step S120: Determine the current correlation value between the baseband signal and the local target master synchronization signal sequence.

[0024] The baseband signal and the local target primary synchronization signal sequence are correlated to determine the current correlation value. This quantized value is used to determine whether the currently received baseband signal contains the true primary synchronization signal (PSS). A higher correlation value indicates a higher degree of synchronization between the PSS signal in the baseband signal and the local target primary synchronization signal sequence. Conversely, a lower correlation value indicates a lower degree of synchronization between the PSS signal in the baseband signal and the local target primary synchronization signal sequence.

[0025] In some examples, a time-domain sliding correlation algorithm can be used to detect the correlation between the baseband signal and the local target master synchronization signal sequence. Because this algorithm has simple computational logic, it can ensure the timeliness of determining the current correlation value, thus contributing to efficient determination.

[0026] In other examples, a frequency domain fast correlation algorithm can be used to detect the correlation between the baseband signal and the local target master synchronization signal sequence based on the fast Fourier transform and inverse fast Fourier transform, thereby effectively reducing the computational overhead of long sequence processing.

[0027] It should be noted that the above example is only used to illustrate the implementation method of the current relevant value. The specific algorithm used can be determined according to actual needs and is not limited here.

[0028] Step S130: Based on the first sampling frequency, determine the historical correlation value corresponding to the first number of historical sampling points closest to the current time.

[0029] Based on the first sampling frequency, the sampling interval between adjacent sampling points can be determined. Then, combined with the current time, the sampling time corresponding to the previous adjacent sampling point and the sampling time corresponding to the next sampling point can be determined. There is a one-to-one correspondence between sampling points and receiving times.

[0030] Since the correlation peaks have local envelope characteristics, in order to eliminate the interference of sidelobe spurious peaks on the true PSS detection, the historical correlation value corresponding to the first number of historical sampling points closest to the current time is determined, so as to combine the current correlation value to analyze the synchronous change trend of the baseband signal, and thus achieve comprehensive screening of effective synchronization peaks.

[0031] In some examples, the historical relevant values ​​corresponding to each historical sampling point can be cached after being determined at the corresponding time, which can ensure the timeliness and reliability of the data obtained at the current time and effectively reduce latency.

[0032] In other examples, the historical correlation values ​​corresponding to each historical sampling point can be determined at the current moment by backtracking and reading the original baseband signal segments corresponding to each historical sampling point, which helps to save storage resources.

[0033] Step S140: If the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value, then the target sampling point is determined as a valid sampling point, and auxiliary synchronization signal detection is performed based on the baseband signal corresponding to the target sampling point to obtain the signal detection result.

[0034] If the historical correlation value corresponding to the target sampling point is the absolute maximum among all historical correlation values ​​and the current correlation value, it indicates that this position is the main energy peak within the correlation peak envelope, and a true master synchronization signal exists in the corresponding baseband signal. Therefore, the target sampling point is used as an effective sampling point to eliminate interference from sidelobe spurious peaks caused by noise and multipath fading. The target sampling point is spaced a second number of sampling intervals from the current time point to adapt to the distribution characteristics of the PSS correlation peak, actively deviating from the dense sidelobe region surrounding the current time point, thereby helping to improve the accuracy of peak identification.

[0035] After confirming that the target sampling point is a valid sampling point, the baseband signal corresponding to the target sampling point is used as the reference for auxiliary synchronization signal detection, based on the time information of that sampling point. Through auxiliary synchronization signal matching and verification, base station identification and timing synchronization confirmation are completed, and the signal detection result is output to support the subsequent establishment of network connections between electronic devices and the base station.

[0036] Step S150: Establish a network connection with the base station based on the signal detection results.

[0037] If the signal detection result is qualified, it indicates that the cell search is successful, and the electronic device can normally access the base station, thus establishing a network connection with the base station.

[0038] In some examples, if the signal detection result is unqualified and the cell search is unsuccessful, the electronic device needs to re-execute the above steps S110-S140 until a qualified signal detection result is obtained, and a network connection is established with the base station to achieve cell search.

[0039] According to the cell search method provided in this disclosure, after determining the current correlation value between the baseband signal received at the current moment and the local target primary synchronization signal sequence, the electronic device combines the historical correlation values ​​corresponding to the nearest first number of historical sampling points to comprehensively analyze the synchronization change trend of the baseband signal, thereby achieving effective screening of the true primary synchronization peak. Furthermore, when determining the baseband signal used for secondary synchronization signal detection, the determination is based on whether the historical correlation value corresponding to the target sampling point is the absolute maximum among all historical correlation values ​​and the current correlation value. This not only avoids interference from sidelobe false peaks caused by noise and multipath fading but also improves the judgment efficiency and ensures the timely triggering of secondary synchronization signal detection. Moreover, establishing a network connection with the base station based on the signal detection results of secondary synchronization signal detection can significantly reduce invalid detection actions while ensuring the reliability of cell search, effectively reducing the power consumption of the electronic device and extending its battery life.

[0040] In some embodiments, such as Figure 2 As shown, the local target master synchronization signal sequence may include: a third number of local cyclic prefix sampling points and a fourth number of local master synchronization signal sampling points. The third number of local cyclic prefix sampling points is obtained by truncating the end of the original local master synchronization signal sequence, and the fourth number of local master synchronization signal sampling points are the remaining sampling points of the original local master synchronization signal sequence. The sum of the third and fourth numbers equals the total number of sampling points in the original local master synchronization signal sequence.

[0041] By constructing a local target master synchronization signal sequence in this way, without changing the bit width and depth of the electronic device correlator, the ideal optimal synchronization point obtained by sliding correlation detection can be shifted forward by a third number of sampling points relative to the starting position of the useful symbol of the physical signal, thus achieving pre-anchoring of the synchronization position.

[0042] For example, taking a local original master synchronization signal sequence containing 128 sampling points as an example, the third quantity can be 4, and the fourth quantity can be 124. The process of constructing the local target master synchronization signal sequence can be as follows: Figure 3 As shown, the original local master synchronization signal sequence is (0,1,2…,127). The last four sampling points (124,125,126,127) are extracted and placed at the beginning of the original local master synchronization signal sequence. Then, they are concatenated with the remaining sampling points (0,1,2…,123) of the original local master synchronization signal sequence to obtain the target local master synchronization signal sequence (124,125,126,127,0,1,2…,123). The numbers in parentheses represent the sequence numbers of each sampling point.

[0043] In some embodiments, the third quantity is determined based on the minimum sampling interval between adjacent target sampling points, which is determined by the difference between the first and second quantities. Determining the number of local cyclic prefix sampling points in this way allows for precise matching with characteristics such as sampling point offset patterns and signal timing, making the synchronization anchor position more closely match the energy distribution of the main synchronization signal. This, in turn, effectively avoids spurious sidelobe peaks when determining effective sampling points, improving the accuracy of synchronization judgment. Furthermore, constructing the local target main synchronization signal sequence in this way can mitigate the impact of timing deviations, ensure signal detection performance, lengthen the minimum trigger interval for auxiliary synchronization signal detection, and achieve equivalent frequency reduction processing. This effectively reduces the power consumption of electronic devices while ensuring normal detection functionality. For example, when the first quantity is 7 and the second quantity is 3, the third quantity can be 7-3=4. The minimum time interval for subsequent continuous triggering of the auxiliary synchronization signal output can be lengthened to strictly greater than or equal to 4 sampling points, forcibly reducing the processing cycle from the original 1.92MHz sampling rate to an equivalent 0.48MHz. Alternatively, if the first quantity is 5 and the second quantity is 2, the third quantity can be 5-2=3. The minimum time interval for subsequent continuous triggering of auxiliary synchronization signal output can be extended to strictly greater than or equal to 3 sampling points, thereby forcibly reducing the data throughput based on the original 1.92MHz sampling rate to an equivalent processing cycle of 0.64MHz.

[0044] In some embodiments, the process of detecting auxiliary synchronization signals for baseband signals may include: Step a1: Determine the second sampling rate corresponding to the auxiliary synchronization signal detection based on the first sampling frequency and the third quantity.

[0045] Since the first sampling frequency is the original sampling frequency of the baseband signal, and the third quantity is the preset number of local cyclic prefix sampling points, the third quantity can be used as a sampling frequency division coefficient to divide the original first sampling frequency, thereby obtaining a second sampling rate for auxiliary synchronization signal detection, thus achieving equivalent frequency reduction.

[0046] Step a2: Sample the baseband signal according to the second sampling rate to determine the number of sampling points of the base station cyclic prefix in the baseband signal.

[0047] By resampling the baseband signal through a second sampling, and combining this with the signal frame structure characteristics on the base station side, the number of base station cyclic prefix sampling points contained in the current base station signal can be identified and counted in the resampled data stream. This value represents the actual cyclic prefix length transmitted by the base station.

[0048] Step a3: Determine the anti-timing deviation margin window based on the third quantity and the number of sampling points of the base station cyclic prefix.

[0049] The timing deviation margin window can be understood as a fault tolerance range, used to accommodate timing offset errors generated during signal transmission and sampling.

[0050] The secondary synchronization signal detection operates at a second sampling rate after frequency division, which introduces physical timing deviation. However, the local target primary synchronization signal sequence is configured with a third number of local cyclic prefix sampling points, allowing the synchronization anchor point to be moved forward into the cyclic prefix interval. Under the LTE normal cyclic prefix (Normal CP) length, this forward offset characteristic naturally constructs a timing deviation margin window, absorbing quantization timing errors caused by frequency reduction. The maximum deviation range does not exceed plus or minus the third number, ensuring that when the subsequent secondary synchronization signal detection opens the FFT window, the window boundary always remains within the safe range of the base station's cyclic prefix, effectively avoiding inter-symbol interference (ISI) and ensuring no loss in cell search performance. The left endpoint of the timing deviation margin window is the difference between the third number and the number of sampling points in the base station's cyclic prefix, while the right endpoint is the third number.

[0051] For example, if the first sampling frequency is 1.92MHz, and the second sampling frequency obtained by frequency division is 0.48MHz, after downsampling the 1.92MHz baseband signal to 0.48MHz and completing the resampling, the number of sampling points of the base station cyclic prefix can be 9. If the third quantity is 4, then the anti-timing deviation margin window is [-5,4].

[0052] Step a4: Within the anti-timing deviation margin window, perform auxiliary synchronization signal detection on the baseband signal corresponding to the target sampling point to obtain the signal detection result.

[0053] Since the anti-timing bias margin window can absorb the quantization timing error caused by frequency reduction, the auxiliary synchronization signal detection of the baseband signal corresponding to the target sampling point within the anti-timing bias margin window can ensure that the FFT window boundary is always within the safe range of the base station cyclic prefix, which can effectively offset the timing error caused by large-scale frequency reduction, thereby achieving completely lossless frequency reduction at extremely low cost.

[0054] In some embodiments, step S130 may include: acquiring historical correlation values ​​corresponding to a first number of historical sampling points most recent to the current time through a sliding observation window, based on a first sampling frequency. The primary synchronization signal, after correlation operations, forms a continuous energy envelope, rather than a single-point peak. Acquiring a first number of historical correlation values ​​through a sliding observation window can fully reflect the changing patterns of signal energy. Simultaneously, channel noise, multipath effects, and sidelobe interference can easily cause distortion of single-point data. Therefore, combining the correlation values ​​of multiple continuous sampling points for joint analysis can effectively identify false peaks and improve the accuracy of peak judgment.

[0055] Furthermore, the baseband signal is continuously transmitted by the base station using a streaming transmission method. By limiting the total number of observations of a single correlation value through a sliding observation window, the processing method can be made more real-time, while meeting the implementation requirements of a hardware causal system.

[0056] The sliding observation window is used to simultaneously observe the historical correlation values ​​corresponding to a first number of historical sampling points and the current correlation value corresponding to the current time. The total number of observations in the sliding observation window is equal to the first number plus 1. For example, if the total number of observations in the sliding observation window is 8, then the sliding observation window includes 7 historical sampling points closest to the current time. If the sampling point corresponding to the current time is represented by n, then the sequence of 8 sampling points in the sliding observation window can be as follows: n-7, n-6, n-5, n-4, n-3, n-2, n-1, n.

[0057] In some examples, the target sampling point is located in the middle area of ​​the sliding observation window, and the ratio of the second quantity to the total number of observations is less than or equal to 1 / 2, while the second quantity is greater than or equal to 2.

[0058] Since the correlation energy envelope of the main synchronization signal exhibits a distribution characteristic of being high in the middle and decreasing on both sides, with the peak center concentrated in the middle of the window, when determining the position of the target sampling point within the sliding observation window, it can be set in the middle region of the sliding observation window so that it can correspond to the position of the main energy peak. As a result, compared with the sampling points at the edge of the window, the correlation value here has a higher amplitude and more prominent characteristics, which can improve the synchronization positioning accuracy from the source.

[0059] Furthermore, to enhance anti-interference capabilities, when configuring the second quantity between the target sampling point and the sampling point corresponding to the current time, the ratio of the second quantity to the total number of observations can be set to be less than or equal to 1 / 2. This ensures sufficient sampling point margin between the target sampling point and the left and right boundaries of the window. It also prevents the loss of effective data during channel noise, multipath offset, and short-term signal jitter, enhancing the system's anti-interference capability and reducing the probability of peak misjudgment. Since the sampling points at the beginning and end of the window are easily affected by the sliding truncation effect, leading to poor data integrity, the second quantity can be configured to be greater than or equal to 2. This keeps the target sampling point away from the outermost edge of the window, avoiding the truncation distortion region and ensuring that the correlation values ​​used for decision-making are true and reliable. For example, if the total number of observations in the sliding observation window is 8, and the correlation sequence is {n-7, n-6, n-5, n-4, n-3, n-2, n-1, n}, then the target sampling point can be n-3. Alternatively, if the total number of observations in the sliding observation window is 6, and the correlation sequence is {n-5, n-4, n-3, n-2, n-1, n}, then the target sampling point can be n-2.

[0060] Furthermore, the second quantity is a core parameter for calculating the minimum sampling interval and determining the third quantity. By limiting it as described above, the sampling offset can be kept within a reasonable range, ensuring that subsequent data reading and processing strictly follow causal relationships, which is more in line with the engineering implementation conditions of real-time hardware processing.

[0061] In some embodiments, such as Figure 3 As shown, the cell search method may also include: Step S160: If the historical correlation value corresponding to the target sampling point is not the absolute maximum value among all historical correlation values ​​and the current correlation value, then the target sampling point is determined to be an invalid sampling point, and the step of receiving the baseband signal continuously transmitted by the base station is re-executed at the next reception time.

[0062] If the historical correlation value corresponding to the target sampling point is not the absolute maximum among all historical correlation values ​​and the current correlation value, it indicates that there are larger or equal correlation values ​​among its neighboring sampling points. This location is not the energy peak of the primary synchronization signal. Therefore, to ensure cell search accuracy, the target sampling point can be determined as an invalid sampling point, and the process of receiving the continuously transmitted baseband signal from the base station will be repeated at the next reception time until a qualified signal detection result is obtained, establishing a network connection with the base station, thereby achieving cell search. The next reception time is separated from the current time by one sampling interval.

[0063] The cell search method provided in this disclosure can avoid interference from sidelobe false peaks caused by noise and multipath fading, improve the judgment efficiency, and realize automatic cyclic detection of cell search. While ensuring the reliability of cell search, it can significantly reduce invalid detection actions, effectively reduce the power consumption of electronic devices, and extend the battery life of devices.

[0064] In some optional application scenarios, taking a first sampling rate of 1.92MHz as an example, the total number of observations in the observation sliding window is 8, and the local target master synchronization signal sequence includes 4 local cyclic prefix sampling points and 124 local master synchronization signal sampling points. The cell search process using the cell search method provided in this disclosure can be implemented as follows: The electronic device acquires the baseband signal received at 1.92MHz at the current time. It performs correlation processing on the baseband signal and the local target master synchronization signal sequence to determine the current correlation value at the current moment.

[0065] Based on the observation sliding window, determine the historical correlation values ​​corresponding to the 7 most recent historical sampling points up to the current time. For example, the sampling point sequence in the observation sliding window is {n-7, n-6, n-5, n-4, n-3, n-2, n-1, n}, where n represents the sampling point corresponding to the current time. Then n-7, n-6, n-5, n-4, n-3, n-2, and n-1 are the most recent historical sampling points corresponding to the sampling point at the current time. Among them, the sampling interval between n-1 and n is the shortest, and the sampling interval between n-7 and n is the longest.

[0066] If the target sampling point is n-3, then determine whether the historical correlation value corresponding to n-3 is the absolute maximum value within the observation sliding window. If the historical correlation value corresponding to n-3 is the absolute maximum value within the observation sliding window, then n-3 is determined to be a valid sampling point. Auxiliary synchronization signal detection is performed based on the baseband signal corresponding to n-3, and the signal detection result is obtained. Specifically, based on 1.92MHz and 4 local cyclic prefix sampling points, the second sampling rate used for auxiliary synchronization signal detection is divided to 0.48MHz. At this point, resampling at 0.48MHz allows the number of base station cyclic prefix sampling points for the baseband signal to be 9, with a timing bias margin window of [-5, 4]. Since the timing bias margin window can absorb the quantization timing error caused by frequency reduction, performing auxiliary synchronization signal detection on the baseband signal corresponding to the target sampling point within the timing bias margin window ensures that the FFT window boundary is always within the safe range of the base station cyclic prefix. This effectively offsets the timing error caused by significant frequency reduction, thus achieving completely lossless frequency reduction at extremely low cost.

[0067] If the signal detection result is satisfactory, the electronic device establishes a network connection with the base station.

[0068] If the historical correlation value corresponding to n-3 is not the absolute maximum value in the observation sliding window, then continue to receive baseband signals until a qualified signal detection result is obtained, and establish a network connection with the base station to achieve cell search.

[0069] Among them, the effect of performing cell search in a loop can be Figure 4 As shown.

[0070] With the same inventive concept, this disclosure also provides a cell search device deployed on an electronic device. For example... Figure 5 As shown, the cell search device 200 may include: The receiving module 210 is used to receive baseband signals continuously transmitted by the base station; The first processing module 220 is used to determine the current correlation value between the baseband signal and the local target master synchronization signal sequence; The second processing module 230 is used to determine the historical correlation value corresponding to the first number of historical sampling points closest to the current time according to the first sampling frequency, wherein the sampling points correspond one-to-one with the receiving time; The third processing module 240 is used to determine the target sampling point as a valid sampling point if the historical correlation value corresponding to the target sampling point is the absolute maximum value among all historical correlation values ​​and the current correlation value, and to perform auxiliary synchronization signal detection based on the baseband signal corresponding to the target sampling point to obtain the signal detection result. The second number of sampling intervals is between the receiving time corresponding to the target sampling point and the current time. The connection module 250 is used to establish a network connection with the base station based on the signal detection results.

[0071] In some embodiments, the local target master synchronization signal sequence includes: a third number of local cyclic prefix sampling points and a fourth number of local master synchronization signal sampling points, wherein the third number of local cyclic prefix sampling points are truncated from the end of the local original master synchronization signal sequence, and the fourth number of local master synchronization signal sampling points are the remaining sampling points of the local original master synchronization signal sequence, and the sum of the third number and the fourth number is equal to the total number of sampling points of the local original master synchronization signal sequence.

[0072] In some embodiments, the third quantity is determined based on the minimum sampling interval between adjacent target sampling points, which is determined based on the difference between the first quantity and the second quantity.

[0073] In some embodiments, the third processing module 240 includes: a first determining unit, configured to determine a second sampling rate corresponding to the auxiliary synchronization signal detection based on a first sampling frequency and a third quantity; a second determining unit, configured to sample the baseband signal according to the second sampling rate to determine the number of sampling points of the base station cyclic prefix in the baseband signal; a third determining unit, configured to determine an anti-timing deviation margin window based on the third quantity and the number of sampling points of the base station cyclic prefix, wherein the left endpoint of the anti-timing deviation margin window is the difference between the third quantity and the number of sampling points of the base station cyclic prefix, and the right endpoint of the anti-timing deviation margin window is the third quantity; and a detection unit, configured to perform auxiliary synchronization signal detection on the baseband signal corresponding to the target sampling point within the anti-timing deviation margin window to obtain a signal detection result.

[0074] In some embodiments, the second processing module 230 includes: according to the first sampling frequency, obtaining the historical correlation value corresponding to the first number of historical sampling points closest to the current time through a sliding observation window, wherein the sliding observation window is used to simultaneously observe the historical correlation value corresponding to the first number of historical sampling points and the current correlation value corresponding to the current time, and the total number of observations of sampling points in the sliding observation window is equal to the first number plus 1.

[0075] In some embodiments, the target sampling point is located in the middle area of ​​the sliding observation window, and the ratio of the second number to the total number of observations is less than or equal to 1 / 2, and the second number is greater than or equal to 2.

[0076] In some embodiments, the third processing module 240 is further configured to: if the historical correlation value corresponding to the target sampling point is not the absolute maximum value among all historical correlation values ​​and the current correlation value, determine the target sampling point as an invalid sampling point, and re-execute the step of receiving the baseband signal continuously transmitted by the base station at the next receiving time, wherein the next receiving time is separated from the current time by a sampling interval.

[0077] Regarding the cell search device in the above embodiments, the specific methods by which each module performs its operations have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0078] Based on the same inventive concept, such as Figure 6 As shown, one embodiment of this disclosure provides an electronic device 300. The electronic device includes one or more processors 310, a memory 320, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components are interconnected via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the electronic device, including instructions stored in or on memory to display graphical information of a GUI on an external input / output device (such as a display device coupled to the interface). In some alternative embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple electronic devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 6 Take the 310 processor as an example.

[0079] Processor 310 may be a central processing unit, a network processor, or a combination thereof. Processor 310 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GPA), or any combination thereof.

[0080] The memory 320 stores instructions executable by at least one processor 310 to cause the at least one processor 310 to perform the cell search method shown in the above embodiments.

[0081] The memory 320 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the electronic device. Furthermore, the memory 320 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 320 may optionally include memory remotely located relative to the processor 310, and these remote memories may be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0082] The memory 320 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 320 may also include a combination of the above types of memory.

[0083] The electronic device 300 also includes an input device 330 and an output device 340. The processor 310, memory 320, input device 330, and output device 340 can be connected via a bus or other means. Figure 6 Taking the example of a connection between China and Israel via a bus.

[0084] Input device 330 can receive input numerical or character information, and generate key signal inputs related to user settings and function control of the electronic device, such as a touchscreen, keypad, mouse, trackpad, touchpad, joystick, one or more mouse buttons, trackball, joystick, etc. Output device 340 may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The aforementioned display devices include, but are not limited to, liquid crystal displays, light-emitting diodes, displays, and plasma displays. In some alternative embodiments, the display device may be a touchscreen.

[0085] Based on the same inventive concept, this disclosure also provides a computer-readable storage medium storing a program for performing the cell search method of any of the foregoing embodiments.

[0086] This disclosure uses specific terms to describe embodiments of the present disclosure. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the present disclosure. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the present disclosure can be appropriately combined.

[0087] In the context of this disclosure, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0088] Similarly, it should be noted that, in order to simplify the description of this disclosure and thus aid in the understanding of one or more embodiments, the foregoing description of embodiments of this disclosure may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of this disclosure requires more features than the features claimed. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0089] The basic concepts have been described above. It is obvious that the above disclosure is merely illustrative and does not constitute a limitation of this disclosure. Although not explicitly stated herein, various modifications, improvements, and corrections may be made to this disclosure by those skilled in the art. Such modifications, improvements, and corrections are suggested in this disclosure and therefore remain within the spirit and scope of the embodiments of this disclosure.

Claims

1. A cell search method, characterized in that, Applied to electronic devices, the method includes: Receive baseband signals continuously transmitted by the base station; Determine the current correlation value between the baseband signal and the local target master synchronization signal sequence; Based on the first sampling frequency, determine the historical correlation value corresponding to the first number of historical sampling points closest to the current time, wherein the sampling points correspond one-to-one with the receiving time; If the historical correlation value corresponding to the target sampling point is the absolute maximum value among all the historical correlation values ​​and the current correlation value, then the target sampling point is determined to be a valid sampling point, and auxiliary synchronization signal detection is performed based on the baseband signal corresponding to the target sampling point to obtain the signal detection result, wherein the target sampling point and the current time are separated by a second number of sampling intervals; A network connection is established with the base station based on the signal detection results.

2. The cell search method according to claim 1, characterized in that, The local target master synchronization signal sequence includes: a third number of local cyclic prefix sampling points and a fourth number of local master synchronization signal sampling points, wherein the third number of local cyclic prefix sampling points are obtained from the tail of the local original master synchronization signal sequence, and the fourth number of local master synchronization signal sampling points are the remaining sampling points of the local original master synchronization signal sequence. The sum of the third number and the fourth number is equal to the total number of sampling points of the local original master synchronization signal sequence.

3. The cell search method according to claim 2, characterized in that, The third quantity is determined based on the minimum sampling interval between adjacent target sampling points, and the minimum sampling interval is determined based on the difference between the first quantity and the second quantity.

4. The cell search method according to claim 2 or 3, characterized in that, The auxiliary synchronization signal detection based on the baseband signal corresponding to the target sampling point, to obtain the signal detection result, includes: Based on the first sampling frequency and the third quantity, determine the second sampling rate corresponding to the auxiliary synchronization signal detection; The baseband signal is sampled according to the second sampling rate to determine the number of sampling points of the base station cyclic prefix in the baseband signal; Based on the third quantity and the number of sampling points of the base station cyclic prefix, a timing deviation margin window is determined, wherein the left endpoint of the timing deviation margin window is the difference between the third quantity and the number of sampling points of the base station cyclic prefix, and the right endpoint of the timing deviation margin window is the third quantity. Within the anti-timing deviation margin window, the baseband signal corresponding to the target sampling point is subjected to auxiliary synchronization signal detection to obtain the signal detection result.

5. The cell search method according to claim 1, characterized in that, The step of determining the historical correlation value corresponding to the first number of historical sampling points closest to the current time based on the first sampling frequency includes: Based on the first sampling frequency, the historical correlation value corresponding to the first number of historical sampling points closest to the current time is obtained through a sliding observation window. The sliding observation window is used to simultaneously observe the historical correlation value corresponding to the first number of historical sampling points and the current correlation value corresponding to the current time. The total number of observations of sampling points in the sliding observation window is equal to the first number plus 1.

6. The cell search method according to claim 5, characterized in that, The target sampling point is located in the middle area of ​​the sliding observation window, and the ratio of the second quantity to the total number of observations is less than or equal to 1 / 2, while the second quantity is greater than or equal to 2.

7. The cell search method according to claim 1, characterized in that, The method further includes: If the historical correlation value corresponding to the target sampling point is not the absolute maximum value among all the historical correlation values ​​and the current correlation value, then the target sampling point is determined to be an invalid sampling point, and the step of receiving the baseband signal continuously transmitted by the base station is re-executed at the next receiving time, wherein the next receiving time is separated from the current time by a sampling interval.

8. A cell search device, characterized in that, Deployed in an electronic device, the device includes: The receiving module is used to receive baseband signals continuously transmitted by the base station; The first processing module is used to determine the current correlation value between the baseband signal and the local target master synchronization signal sequence; The second processing module is used to determine the historical correlation value corresponding to the first number of historical sampling points closest to the current time based on the first sampling frequency, wherein the sampling points correspond one-to-one with the receiving time; The third processing module is used to determine the target sampling point as a valid sampling point if the historical correlation value corresponding to the target sampling point is the absolute maximum value among all the historical correlation values ​​and the current correlation value, and to perform auxiliary synchronization signal detection based on the baseband signal corresponding to the target sampling point to obtain a signal detection result, wherein the receiving time corresponding to the target sampling point is spaced apart from the current time by a second number of sampling intervals. A connection module is used to establish a network connection with the base station based on the signal detection results.

9. An electronic device, characterized in that, include: A memory and a processor are communicatively connected, the memory stores computer instructions, and the processor performs the cell search method according to any one of claims 1-7 by executing the computer instructions.

10. A computer-readable storage medium storing a program for performing the cell search method according to any one of claims 1-7.

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