Method for estimating clock frequency deviation of public network downlink receiver based on linear fitting

Abstract

This application relates to the field of wireless communication technologies, and discloses a method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting, which includes the following steps: The receiver listens to the public network synchronization channel and captures the frame header signal. The frame header signal includes multiple frame header signals, the packet header, the synchronization frame of the broadcast signal, and the key frame for frequency deviation estimation. Each time the frame header signal is captured, the timestamp received by the receiver is recorded; The linear fitting algorithm is used to analyze the timestamps of the frame header signals, and the clock frequency deviation between the receiver and the base station is estimated by minimizing the error function; The clock of the receiver is adjusted based on the estimated clock frequency deviation. By introducing frequency interpolation technology, dynamic adjustment mechanism, and multipath effect compensation, the present invention significantly improves the clock synchronization accuracy, ensures the stable operation of the receiver under signal loss, interference, and complex environments, and enhances the robustness and reliability of the system.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and specifically to a method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting. Background Art

[0002] In modern communication systems, clock synchronization is a core technology to ensure the accuracy of data transmission and the reliability of the system. Especially in public network downlink receivers, the estimation and synchronization of clock frequency deviation directly affect the reception and demodulation of signals. In wireless communication, there is often a certain deviation between the clock frequencies of the receiver and the base station. If this deviation cannot be corrected in time, it will lead to signal distortion and even data loss.

[0003] In the prior art, clock synchronization mainly relies on capturing the timestamp data of the frame header signal and estimating the clock deviation by analyzing the signal arrival time. Based on these technologies, the clock frequency deviation estimation can maintain the synchronization of the system to a certain extent. Especially in an environment with good signal quality, these methods can achieve relatively accurate clock synchronization. At the same time, the prior art also has a certain ability to compensate for multipath effects and can handle some common signal interferences and fluctuations. The existing methods can be well applied in a relatively stable wireless environment, and their calculation methods are relatively simple, and they can quickly complete the clock synchronization task.

[0004] However, the prior art still has obvious deficiencies when facing complex environments, especially in the cases of signal loss, severe interference or multipath propagation. Traditional methods usually rely on a single frame header signal, and the accuracy of frequency deviation estimation is relatively low. It is easily affected by signal jitter and noise, resulting in inaccurate synchronization. More seriously, when the base station signal is lost or interfered, the prior art cannot predict and fill the frequency deviation during the signal interruption through interpolation and other technologies, which easily causes the clock synchronization to be interrupted. In addition, the prior art does not correct the clock frequency deviation caused by multipath propagation finely enough, and cannot make full use of the signal strength distribution and arrival time difference, resulting in insufficient synchronization accuracy. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting, which solves the problems of insufficient accuracy of frequency deviation estimation, clock synchronization interruption when signals are lost or interfered, and inaccurate clock synchronization in a multipath propagation environment in the prior art.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting, comprising the following steps:

[0007] The receiver listens to the public network synchronization channel and captures the frame header signal, which includes multiple frame header signals, data packet headers, synchronization frames of broadcast signals, and key frames for frequency deviation estimation. Each time the frame header signal is captured, the timestamp received by the receiver is recorded;

[0008] Use the linear fitting algorithm to analyze the timestamps of the frame header signals, and estimate the clock frequency deviation between the receiver and the base station by minimizing the error function;

[0009] Based on the estimated clock frequency deviation, adjust the clock of the receiver to synchronize the received signal with the base station signal;

[0010] When the base station signal is lost or interfered, dynamically adjust the clock frequency deviation of the receiver according to the timestamp data of the captured frame header signals and the frequency deviation estimation results obtained by the linear fitting algorithm;

[0011] When the base station signal is interrupted, use the frequency interpolation technique to predict and fill the clock frequency deviation during the signal interruption;

[0012] In a multipath propagation environment, based on the intensity distribution and time-of-arrival difference information of the received frame header signals, use the multipath effect modeling and signal delay compensation algorithm to correct the timestamp data.

[0013] Preferably, the linear fitting algorithm includes:

[0014] Use the least squares method to analyze the timestamp data of multiple captured frame header signals, and estimate the clock frequency deviation between the receiver and the base station by minimizing the error between the signal timestamp and the ideal timestamp;

[0015] The linear fitting algorithm optimizes the frequency deviation estimation results through the fitting process.

[0016] Preferably, the dynamic adjustment includes:

[0017] When a new frame header signal is received, adjust the clock frequency deviation of the receiver in real time according to the frequency deviation estimation result of the previous moment and the current signal timestamp data;

[0018] The receiver ensures the timing of the signal is synchronized with the base station by dynamically adjusting the deviation value.

[0019] Preferably, the frequency interpolation includes:

[0020] Use the historical frame header signal timestamp data captured by the receiver during the signal interruption, and combine the linear fitting results to predict the clock deviation at future moments, and interpolate to calculate and fill the clock frequency change during the signal missing period;

[0021] The interpolation algorithm can accurately estimate the deviation of the receiver clock during the signal loss period according to the changing trend of the previous frequency deviation.

[0022] Preferably, the timestamp data analysis includes:

[0023] Performing linear fitting on the timestamp data of multiple frame header signals, and estimating the frequency deviation of the receiver clock by minimizing the difference between the signal arrival timestamp and the ideal timestamp;

[0024] During the fitting process, by optimizing the error in the calculation process, the accurate frequency deviation between the receiver clock and the base station clock is finally obtained.

[0025] Preferably, the corrected timestamp data includes:

[0026] Based on the intensity distribution and time arrival difference of the captured frame header signals, using multipath effect modeling to correct the signal timing data;

[0027] During the correction process, by compensating for the time deviation caused by multipath propagation during signal transmission, the accuracy of clock frequency deviation estimation is further optimized.

[0028] Preferably, the frame header signal capture includes:

[0029] The receiver continuously monitors the public network synchronization channel, and records the timestamp data at each signal capture by detecting the key frames of multiple frame header signals and other signals;

[0030] During the signal capture process, the receiver classifies and marks different types of synchronization signals.

[0031] Preferably, the minimization error function includes:

[0032] Minimizing the error between the capture timestamp data of multiple frame header signals and the base station reference timestamp, optimizing the fitting function, and obtaining the best estimated value of the clock frequency deviation;

[0033] By ensuring the minimization of the error function, the deviation caused by external noise, interference, and multipath effects is reduced.

[0034] Preferably, the signal delay compensation includes:

[0035] According to the propagation characteristics of the received frame header signals, combined with the time arrival difference of the signals and the intensity distribution of the multipath signals, compensating for the time delay caused by the multipath effect through modeling;

[0036] Through multipath compensation, the timestamp data can be accurately estimated and corrected, further improving the accuracy of frequency deviation estimation.

[0037] Preferably, the base station signal synchronization includes:

[0038] During the process of estimating the clock frequency deviation between the receiver and the base station, continuously update the clock synchronization status of the receiver;

[0039] Preprocess the captured frame header signal to optimize the signal timing and ensure that the signal is synchronized with the base station after frequency deviation calibration;

[0040] During the process of estimating the frequency deviation, use real-time monitoring technology to evaluate the signal quality.

[0041] The present invention provides a method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting. It has the following beneficial effects:

[0042] 1. The present invention adopts a frequency deviation estimation method based on linear fitting. By capturing the frame header signal and timestamp data multiple times, the frequency deviation between the receiver and the base station is estimated, achieving the technical effect of improving the clock synchronization accuracy. Compared with the method of single signal capture and frequency deviation estimation in the prior art, the present invention can effectively reduce the influence of interference and noise through the capture of multiple frames of signals, ensuring more stable and reliable clock synchronization in a complex wireless environment.

[0043] 2. The present invention introduces a dynamic adjustment mechanism. By real-time monitoring the signal state and dynamically adjusting the clock of the receiver based on the frequency deviation estimation result, the technical effect of maintaining clock synchronization in the case of base station handover and signal loss is achieved. Compared with the static frequency deviation estimation method in the prior art, the present invention can quickly respond to the change of signal quality and avoid the synchronization error problem caused by signal interference or handover in the traditional method.

[0044] 3. The present invention uses frequency interpolation technology to compensate for the clock deviation during signal interruption. Even in the case of base station signal loss, the receiver can still maintain high-precision clock synchronization, achieving the technical effect of maintaining clock continuity. Compared with the defect in the prior art that cannot handle long-term signal loss, the present invention can use the previous frequency deviation estimation result to predict and fill the clock deviation during signal loss, avoiding clock synchronization interruption.

[0045] 4. The present invention uses the multipath effect compensation technology to correct the clock frequency deviation caused by multipath propagation by combining the intensity of the received frame header signal and the arrival time difference, achieving the technical effect of improving the clock synchronization accuracy. Compared with the method in the prior art that lacks effective compensation for multipath propagation, the present invention can accurately correct the timestamp data, thus significantly reducing the error caused by multipath effect on clock synchronization and improving the robustness of the system in a complex environment. Description of the Drawings

[0046] Figure 1 Schematic diagram of the method flow of the present invention. Specific implementation mode

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] Please refer to the atta Figure 1 chments. The embodiments of the present invention provide a method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting, including the following steps:

[0049] S1. The receiver listens to the public network synchronization channel and captures the frame header signal through the receiver. The frame header signal includes multiple frame header signals, packet headers, synchronization frames of broadcast signals, and key frames for frequency deviation estimation. Each time the frame header signal is captured, the timestamp received by the receiver is recorded;

[0050] By analyzing the timestamps of the captured multiple frame header signals, one of the key steps in this embodiment is to further process these timestamp data through a linear fitting algorithm to estimate the clock frequency deviation between the receiver and the base station. For this purpose, in this process, the accuracy and real-time performance of capturing and recording timestamps are crucial for subsequent frequency deviation estimation.

[0051] Generally, the receiver continuously listens to the public network synchronization channel and receives various synchronization signals. The types of synchronization signals can be multiple frame header signals, packet headers, synchronization frames of broadcast signals, etc. Each synchronization signal has certain synchronization characteristics, and the receiver needs to identify and process these signals. When capturing these signals, the receiver records the timestamp information of the current signal in real time. To ensure the accuracy of clock frequency deviation estimation, the receiver not only needs to capture the frame header signal, but also needs to ensure that the recorded timestamp has high accuracy and reliability.

[0052] For example, the receiver can use the frame header of the signal, the broadcast synchronization frame, etc. as synchronization reference points. These synchronization signals can be key frames in the signal frames transmitted by broadcast or transmission. For example, the packet header may contain relevant information about time synchronization, and the synchronization frame of the broadcast signal can be used as a global synchronization benchmark.

[0053] During the process of capturing each signal, the receiver records the timestamps when the header signals arrive each time. For each captured signal, the receiver accurately records the current time. The purpose of doing this is to compare these timestamps with the ideal timestamps of the base station through subsequent data processing, and then estimate the frequency deviation of the receiver's clock. Specifically, there may be clock deviations between the receiver's clock and the base station's clock due to factors such as temperature fluctuations and power fluctuations, and these deviations are estimated and adjusted through subsequent algorithms.

[0054] When capturing the header signal, the receiver compares the received signal with the standard time through precise hardware and software synchronization mechanisms and records accurate timestamps. The timestamp data will be stored and passed to the next analysis module for subsequent processing.

[0055] For example, in a specific implementation, the receiver forms a dataset of timestamps by frequently capturing and recording the timestamps of signals. , and these data will be used in the subsequent frequency deviation estimation step. The captured data includes not only the timestamps of the header signals but also the timestamp data of other important signals such as broadcast synchronization frames.

[0056] As an option, the receiver can classify and label each header signal by detecting different types of synchronization signals. For example, the receiver can distinguish which signals are packet headers and which are key frames for frequency deviation estimation. The synchronization methods of each signal are different, and the receiver will classify according to the characteristics of different signals so as to select suitable synchronization signals for analysis in the subsequent frequency deviation estimation process.

[0057] Specifically, the receiver can set different marking rules. For the key frames for frequency deviation estimation, the receiver will preferentially capture and record these signals because the important synchronization information they carry can provide a more accurate reference for frequency deviation estimation. To ensure synchronization accuracy, the receiver can also perform selective capture based on factors such as the strength of different signals and the transmission path.

[0058] A core technical point of the present invention is the accuracy of recording timestamp data. During the signal capture process, the receiver not only records the timestamps but also ensures the reliability of the timestamp data. Since wireless signals are affected by various factors during transmission, such as noise, interference, and multipath propagation, the recording of each timestamp must undergo strict calibration and verification to ensure its accuracy.

[0059] In some embodiments, the receiver will use a high-precision hardware clock and cooperate with a software algorithm to precisely synchronize the captured signals. The received timestamp not only includes the time when the receiver actually captures the signal, but also takes into account factors such as propagation delay and environmental impact, and performs necessary time synchronization calibration.

[0060] During this process, each timestamp recorded by the receiver and the ideal timestamp of the base station The deviation between them will be analyzed by a linear fitting algorithm. Specifically, the estimation process of the clock frequency deviation of the receiver is carried out through the following formula:

[0061] ;

[0062] where is the time deviation of the th signal; is the actual timestamp recorded by the receiver, is the timestamp under ideal conditions. After analyzing the timestamps of multiple signals through the linear fitting algorithm, the clock frequency deviation between the receiver and the base station and the propagation delay can be obtained.

[0063] Through the above steps, the receiver can generate an accurate clock frequency deviation estimation result, and then adjust the clock synchronization to ensure consistency with the base station's clock.

[0064] S2. Use the linear fitting algorithm to analyze the timestamps of the frame header signals, and estimate the clock frequency deviation between the receiver and the base station by minimizing the error function;

[0065] After the receiver captures the frame header signal in the public network synchronization channel and records the timestamp, it uses the linear fitting algorithm to analyze the captured timestamp data. This analysis estimates the clock frequency deviation between the receiver and the base station by minimizing the error function. This process immediately follows the signal capture and timestamp recording in the previous step, and its purpose is to finally achieve precise synchronization between the receiver clock and the base station clock through accurate analysis of the frame header signal timestamps.

[0066] Generally, when the receiver listens for and captures the frame header signal, it will record the corresponding timestamp . These timestamp data are used for subsequent frequency deviation estimation. The timestamp of each frame header signal is the arrival time of the signal captured by the receiver according to the local clock. There is a certain deviation between these timestamps and the ideal timestamp of the base station. The receiver needs to analyze these timestamp data to estimate the clock frequency deviation.

[0067] During this analysis process, the receiver estimates the frequency offset by minimizing the following error function:

[0068] ;

[0069] where, is the timestamp in the ideal case; is the number of captured frame header signals; is the clock frequency offset between the receiver and the base station. When solving this function, the obtained is the frequency offset of the receiver; : the error function, representing the estimation error corresponding to the receiver clock frequency offset The goal is to minimize this error function to obtain the best estimated value of the clock frequency offset; is the actual timestamp of the th frame header signal captured by the receiver.

[0070] Through the fitting process, the receiver can optimize the estimated value of the frequency offset according to the captured timestamp data. Specifically, the fitting process will optimize the fitting result based on the timestamps of multiple frame header signals to ensure the minimization of the error function, thereby minimizing the clock frequency offset between the receiver and the base station. This step is crucial for improving the clock synchronization accuracy.

[0071] For example, in practical applications, if the receiver obtains timestamps from multiple frame header signals, then by linearly fitting the errors of these timestamps, the receiver can deduce the frequency offset from the base station clock. Specifically, the fitting process obtains the precise frequency offset between the receiver clock and the base station clock by optimizing the error in the calculation process.

[0072] In the implementation process, minimizing the error function is one of the key steps. During the minimization process, the receiver accumulates the differences between all captured timestamp data and the base station reference timestamp, and obtains the best estimated value of the frequency offset by calculating the minimum of the sum of squared errors. This process not only helps to eliminate clock offsets caused by factors such as noise, interference, or multipath effects, but also provides high-precision estimated results of the clock frequency offset in a complex communication environment.

[0073] By minimizing the error function, the receiver can accurately estimate the clock frequency offset, thereby improving the accuracy of time synchronization. For example, in an environment where the signal is interfered, by minimizing the error function, the receiver can effectively reduce the influence of external noise and further improve the synchronization accuracy.

[0074] In some embodiments, the receiver may perform a more accurate fitting analysis by combining more signal features (such as phase information, channel estimation, etc.). By introducing more complex signal analysis techniques, the accuracy of frequency deviation estimation can be further optimized, especially in cases where the signal quality is poor or the network environment is complex.

[0075] In addition, more advanced mathematical methods, such as weighted least squares, may be involved in the fitting process to handle the reliability differences of certain header signals. The weighted least squares method can reduce the impact of unreliable header signals on the fitting result by weighting them, thereby further improving the accuracy of overall frequency deviation estimation.

[0076] S3. Adjust the clock of the receiver based on the estimated clock frequency deviation to synchronize the received signal with the base station signal;

[0077] After the receiver completes the capture of the header signal, timestamp recording, and estimation of the clock frequency deviation through the linear fitting algorithm, the receiver will adjust its local clock based on the estimated frequency deviation to synchronize the received signal with the base station signal. This step is a natural continuation of the aforementioned signal capture and frequency deviation estimation, and its purpose is to ensure that the receiver can accurately synchronize to the base station's clock so that the signal can be demodulated in the correct timing sequence.

[0078] The process of adjusting the receiver's clock involves the receiver correcting its clock frequency in real time according to the estimation result of the frequency deviation, thereby ensuring that the received signal is in the same timing sequence as the base station signal. This step is crucial for the subsequent stable transmission and decoding of the signal.

[0079] Generally, after the receiver completes signal capture and estimates the clock frequency deviation through the linear fitting algorithm, the receiver will adjust its clock according to the frequency deviation to keep the received signal synchronized with the base station signal. In a typical implementation, the receiver will adjust the clock according to the following formula:

[0080] ;

[0081] where is the adjusted receiver clock time; is the actual timestamp recorded by the receiver; is the ideal timestamp of the base station; is the clock frequency deviation estimated by the aforementioned linear fitting algorithm.

[0082] Specifically, the receiver will calculate the value by which its local clock needs to be adjusted according to the frequency deviation . If the frequency deviation If it is positive, the receiver clock needs to decrease the timestamp; if it is negative, it needs to increase the timestamp. This adjustment ensures that the received signal is synchronized with the timing of the base station signal, avoiding data errors caused by inconsistent clock frequencies.

[0083] As an option, the receiver continuously monitors and adjusts the clock frequency deviation. In some embodiments, the receiver may perform multiple clock adjustment operations to gradually optimize the clock synchronization accuracy. At each adjustment, the receiver adjusts the clock dynamically based on the estimated frequency deviation to ensure that the timing of the signal is synchronized with the base station signal.

[0084] In a possible implementation, the receiver dynamically adjusts the clock frequency by continuously capturing the header signal and combining the aforementioned estimated frequency deviation. This process can further eliminate the influence of noise and interference in the signal, ensuring that the receiver clock gradually approaches the ideal synchronization state of the base station clock.

[0085] In some embodiments, the receiver may also combine other characteristics of the signal, such as signal strength, transmission distance, etc., for further clock adjustment optimization. Through multi-dimensional information analysis, the receiver can achieve more accurate clock synchronization and still maintain high-precision frequency deviation estimation and clock synchronization in complex environments.

[0086] Specifically, the receiver can also adopt an adaptive algorithm to predict the change trend of the frequency deviation and make clock adjustments in advance. This prediction algorithm can improve the response speed of clock adjustment, enabling the receiver to quickly adapt to the changes in the base station signal in a dynamic environment.

[0087] To improve the accuracy of clock adjustment, the receiver may adopt an incremental adjustment method instead of making a large-scale clock adjustment at once. Incremental adjustment helps to reduce interference to the received signal and avoid signal errors that may be caused by large-scale frequency deviation adjustment.

[0088] In addition, the receiver may evaluate the accuracy of the frequency deviation adjustment in real time and adjust the strategy according to the actual effect. This real-time feedback mechanism can effectively improve the stability of clock synchronization, especially in an environment where base station handovers are frequent or the signal quality is unstable.

[0089] S4. When the base station signal is lost or interfered, dynamically adjust the receiver clock frequency deviation according to the timestamp data of the captured header signal and the frequency deviation estimation result obtained through the linear fitting algorithm;

[0090] When the receiver loses the base station signal or is interfered with, based on the timestamp data of the captured frame header signal and the frequency deviation estimation result obtained through the linear fitting algorithm, the receiver can dynamically adjust its clock frequency deviation. This adjustment method is closely connected with the clock frequency deviation estimation in the previous steps, ensuring that the receiver can still maintain a high clock synchronization accuracy in case of signal loss or interference.

[0091] Specifically, in case of signal loss or interference, the receiver will perform dynamic adjustment of the clock according to the timestamp data of the historically captured frame header signal and the frequency deviation result estimated by the linear fitting algorithm in the early stage. This process ensures that even when the signal is interrupted or the quality deteriorates, the receiver's clock can still be automatically corrected according to the estimated frequency deviation trend, avoiding errors caused by clock inconsistency in the system.

[0092] Generally, when the receiver normally receives the frame header signal, it has completed the preliminary estimation of the clock frequency deviation and uses this estimation result to synchronize the base station clock. If the base station signal is lost or interfered with during the reception process, the receiver will not be able to immediately obtain new timestamp data, and thus may not be able to perform immediate clock synchronization adjustment. Therefore, the receiver will perform dynamic adjustment of the clock frequency according to the previous frequency deviation estimation result, combined with the currently captured partial or historical frame header signal data.

[0093] Specifically, the receiver utilizes the previously estimated frequency deviation and the signal timestamp data captured previously to predict the change trend of the clock deviation. This process ensures that the receiver's clock can be adjusted according to the previously estimated trend during the signal loss period.

[0094] In a typical embodiment, the receiver may use the following formula for dynamic adjustment of the frequency deviation:

[0095] ;

[0096] where, is the adjusted clock frequency deviation; is the previously estimated frequency deviation; is the change rate of the frequency deviation; is the previous moment; is the current moment; represents a small time interval or increment, usually used as a variable in integration. This interpolation method is based on the change trend of the previous frequency deviation and can continue to maintain clock synchronization before the signal is restored.

[0097] Specifically, when the receiver detects a signal interruption or severe interference, it adjusts the clock based on historical data. Instead of waiting for the signal to resume, the receiver actively uses the previous frequency deviation estimation value to predict the clock frequency deviation at future moments. The key to this process is to calculate the predicted future frequency deviation change through interpolation, and then adjust the receiver clock to keep it close to the base station clock state.

[0098] For example, the receiver uses the frequency deviation obtained through the linear fitting algorithm in the early stage and the corresponding timestamps, combines them with the timestamp data of the partial frame header signals captured currently, and uses the interpolation algorithm to predict the frequency deviation at the current moment. By adjusting the frequency deviation of the receiver clock, the receiver can continue to maintain clock synchronization before the signal resumes, ensuring the accurate demodulation of subsequent signals.

[0099] As an option, the receiver can also further adjust the clock synchronization strategy based on the quality assessment of the external signal. When the received frame header signal is severely interfered, the receiver increases the weight of the previous frequency deviation estimation result, thereby reducing the impact of noise on clock synchronization. In the case of less interference or better signal quality, the receiver can further optimize clock synchronization through the real-time updated timestamp data.

[0100] In a possible implementation, when the receiver detects that the base station signal is lost for more than a certain time or the intensity changes too much, it can use the frequency interpolation technique to fill in the clock frequency deviation during the signal interruption. Through this prediction mechanism, the receiver can adjust the clock frequency deviation in advance to ensure the continuity of time synchronization.

[0101] By dynamically adjusting the clock frequency deviation, the receiver can continue to maintain clock synchronization in the case of base station signal loss or interference, avoiding data loss and communication errors caused by clock inconsistency. This technology can significantly improve the robustness of the receiver in complex network environments, especially in scenarios where base station handovers are frequent or the radio environment interference is large.

[0102] For example, when the network environment changes, the receiver can dynamically adjust the clock frequency deviation to ensure that even at moments without signal or with low signal quality, it can accurately maintain clock synchronization until a new signal is received for clock correction.

[0103] S5. When the base station signal is interrupted, use the frequency interpolation technique to predict and fill in the clock frequency deviation during the signal interruption;

[0104] When the receiver is interrupted by the base station signal during the communication process, the frequency interpolation technology is used to predict and fill the clock frequency deviation during the signal interruption to ensure that the receiver clock continues to be synchronized with the base station clock. This step plays an important role in the aforementioned clock frequency deviation estimation and dynamic adjustment process. When the receiver cannot update the clock frequency deviation through the conventional frame header signal, the clock frequency deviation is compensated through the frequency interpolation technology, so that the receiver can continue to stably receive the signal and avoid clock synchronization interruption caused by signal loss.

[0105] Specifically, during the period of base station signal interruption, frequency interpolation technology uses an interpolation algorithm to predict the receiver's clock frequency deviation change based on the previous frequency deviation estimation results and historical timestamp data, and fills the deviation gap caused by signal loss. This process not only reduces the clock error caused by signal loss, but also provides an accurate clock synchronization reference for signal recovery.

[0106] Generally, the receiver, in normal working state, relies on the received frame header signal and the synchronization information of the base station to continuously update the clock frequency deviation. However, in the case of signal interruption or severe quality degradation, the receiver will not be able to obtain new frame header signal data to update the clock frequency deviation. In order to ensure that the receiver can continue to maintain high-precision clock synchronization before the signal is restored, this embodiment adopts frequency interpolation technology to fill the gap of clock frequency deviation during signal interruption.

[0107] Specifically, the receiver uses a frequency interpolation algorithm to calculate the frequency deviation based on the previous estimate. and historical timestamp data , predict the changing trend of the clock deviation, and use the interpolation method to fill the clock frequency change during the signal interruption. The interpolation algorithm calculates the changing trend of the frequency deviation to obtain the expected frequency deviation of the receiver clock during the signal interruption, and adjusts the local clock of the receiver accordingly.

[0108] In one possible implementation, the receiver can use weighted interpolation technology to consider the reliability and accuracy of different timestamp data and use a weighted method to interpolate the frequency deviation. The weighted interpolation method can adjust the interpolation accuracy according to the signal quality and the update frequency of the timestamp, further improving the accuracy of clock synchronization.

[0109] In this weighted interpolation method, newer timestamp data and more reliable frequency deviation estimates will have a greater impact on the interpolation calculation results. This allows the receiver clock to predict the expected clock frequency deviation as accurately as possible before signal recovery.

[0110] To further improve the accuracy of clock synchronization, in some embodiments, the receiver can also adjust the interpolation process multiple times based on real-time feedback. Each time a new signal is received, the receiver can re-estimate the frequency deviation and correct the previous interpolation result. This dynamic adjustment of the interpolation method can more accurately reflect the clock deviation changes in the actual environment and ensure the stability of the clock synchronization process.

[0111] Specifically, the receiver can also combine feedback information such as real-time signal quality and clock synchronization accuracy, and adopt an adaptive interpolation strategy to automatically adjust the parameters of the interpolation algorithm for different environmental conditions. Through this adaptive interpolation, the receiver can flexibly adjust the clock synchronization strategy under different wireless channel conditions to cope with the challenges brought by various complex environments.

[0112] By introducing the frequency interpolation technology, the present invention can effectively fill the clock frequency deviation during signal interruption, and avoid the problem of clock synchronization interruption caused by signal loss or interference. When the receiver cannot obtain new signal data, it can still maintain high-precision synchronization with the base station clock, providing a reliable clock reference for the subsequent signal recovery and demodulation.

[0113] The application of the frequency interpolation technology enables the receiver to dynamically adjust its clock frequency deviation during signal interruption, thereby improving the robustness of the system. Especially in the case of frequent base station handovers or large wireless environment interference, the receiver can rely on historical data and interpolation prediction to maintain the continuity of clock synchronization, significantly enhancing the stability and reliability of the system.

[0114] S6. In a multipath propagation environment, based on the intensity distribution and time-of-arrival difference information of the received header signal, use multipath effect modeling and signal delay compensation algorithm to correct the timestamp data.

[0115] When the receiver is in a multipath propagation environment, use the information such as the intensity distribution and time-of-arrival difference of the received header signal, and combine multipath effect modeling and signal delay compensation algorithm to correct the timestamp data. This step is closely connected with the aforementioned clock frequency deviation estimation and dynamic adjustment process. In a multipath propagation environment, the signal will experience multiple propagation paths, and the arrival time of the signal on each path may be different, resulting in a time error in the received signal. To improve the accuracy of clock synchronization, the receiver uses multipath effect modeling to compensate for these errors and ensure the accuracy of the timestamp data.

[0116] In general, in a wireless communication environment, a receiver may receive multiple signal copies from different propagation paths, and the arrival times and intensities of these signal copies may vary. The multipath propagation effect can cause variations in signal time delays, which in turn affect the accuracy of the received timestamp data. To address this issue, this embodiment employs a multipath effect modeling method based on signal intensity distribution and time-of-arrival differences, and corrects the timestamp data by compensating for the signal propagation delay.

[0117] Specifically, the receiver analyzes the propagation characteristics of each path based on the timestamp data and intensity distribution information of the received multiple frame header signals, and estimates the time deviation introduced by each path. Then, the receiver applies a multipath effect modeling and signal delay compensation algorithm to correct the timestamp error caused by multipath propagation, thereby improving the accuracy of clock synchronization.

[0118] In some embodiments, the receiver estimates the delays of multiple propagation paths by measuring the signal intensity distribution and the time-of-arrival differences of the received signals. The signal arrival time and intensity of each path will be input as parameters into the multipath effect modeling algorithm for processing.

[0119] Specifically, the receiver corrects the error in the timestamp data by modeling the signal delay of each propagation path. Assume that the timestamp of the th signal received by the receiver is caused by the superposition effect of the signal arrival times of multiple paths. The contribution of each path to the timestamp can be expressed as:

[0120] ;

[0121] where is the actual received timestamp of the th signal; is the ideal timestamp; is the time deviation caused by the th propagation path; is the number of paths for multipath propagation. The receiver corrects the captured timestamp data by modeling the delays of all paths.

[0122] As an option, the receiver can more precisely model the multipath effect by combining the signal intensity and time-of-arrival differences. Specifically, for each path, the receiver can estimate its contribution to clock synchronization based on the signal intensity attenuation. Paths with stronger signal intensities will have a greater impact on the final timestamp correction, and conversely, paths with weaker signal intensities will have a smaller contribution to the timestamp.

[0123] In a possible implementation, the receiver can also adopt a weighting method to combine the strength information of different signal paths with the time delay, and calculate the influence weight of each path on the corrected timestamp data. According to these weights, the receiver can perform weighted correction on the timestamp data, thereby optimizing the multipath compensation effect.

[0124] Specifically, during the correction process, the receiver optimizes the timestamp data through the following steps: First, the receiver determines the time delay of each path based on the multipath effect modeling algorithm; then, the receiver combines these time delays with the signal strength to calculate the contribution of each path to the final timestamp; finally, the receiver corrects the timestamp data based on this information to eliminate the error caused by multipath propagation.

[0125] For example, assume that the signal received by the receiver contains signals from two paths. The signal of path 1 has a stronger strength and an earlier arrival time, while the signal of path 2 has a weaker strength and a slightly later arrival time. The receiver adjusts the timestamp data according to the signal information of these two paths to reduce the time error caused by the multipath effect and ensure that the finally obtained timestamp data is more accurate.

[0126] To further improve the accuracy of multipath effect compensation, the receiver can also adopt an adaptive algorithm to dynamically adjust the compensation strategy according to the signal quality and the real-time measured timestamp data. In the case of good signal quality, the receiver can use a relatively simple linear compensation model; while in the case of poor signal quality or severe multipath effect, the receiver can use more complex compensation algorithms, such as high-order interpolation or least squares fitting, to further improve the correction accuracy.

[0127] This adaptive compensation strategy can automatically select the most suitable compensation method according to different communication environments and signal conditions, thereby ensuring the synchronization accuracy in various environments.

[0128] By introducing the multipath effect modeling and signal delay compensation algorithms, this embodiment can effectively eliminate the clock frequency deviation caused by multipath propagation. The receiver corrects the timestamp data to reduce the error of the signal arrival time, and finally improves the accuracy of clock synchronization. In the case of poor signal quality or complex environment, this technology can significantly improve the clock synchronization stability of the receiver and ensure high-precision synchronization services in the multipath propagation environment.

[0129] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting, characterized in that Including the following steps: The receiver listens to the public network synchronization channel and captures the frame header signal. The frame header signal includes multiple frame header signals, packet headers, synchronization frames of broadcast signals, and key frames for frequency deviation estimation. Each time the frame header signal is captured, the timestamp received by the receiver is recorded; Use the linear fitting algorithm to analyze the timestamps of the frame header signals, and estimate the clock frequency deviation between the receiver and the base station by minimizing the error function; Based on the estimated clock frequency deviation, adjust the clock of the receiver to synchronize the received signal with the base station signal; When the base station signal is lost or interfered, dynamically adjust the clock frequency deviation of the receiver according to the timestamp data of the captured frame header signal and the frequency deviation estimation result obtained by the linear fitting algorithm; When the base station signal is interrupted, use the frequency interpolation technique to predict and fill the clock frequency deviation during the signal interruption period; In a multipath propagation environment, based on the intensity distribution and time of arrival difference information of the received frame header signals, use the multipath effect modeling and signal delay compensation algorithm to correct the timestamp data.

2. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The linear fitting algorithm includes: Use the least squares method to analyze the timestamp data of multiple captured frame header signals, and estimate the clock frequency deviation between the receiver and the base station by minimizing the error between the signal timestamp and the ideal timestamp; The linear fitting algorithm optimizes the frequency deviation estimation result through the fitting process.

3. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, characterized in that, The dynamic adjustment includes: When a new frame header signal is received, adjust the clock frequency deviation of the receiver in real time according to the frequency deviation estimation result of the previous moment and the current signal timestamp data; The receiver ensures the timing of the signal to be synchronized with the base station by dynamically adjusting the clock frequency deviation.

4. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The frequency interpolation includes: Use the historical frame header signal timestamp data captured by the receiver during the signal interruption period, and combine the linear fitting result to predict the clock deviation at future moments, and interpolate to calculate and fill the clock frequency change during the signal missing period; The interpolation algorithm can accurately estimate the deviation of the receiver clock during the signal loss period according to the change trend of the previous frequency deviation.

5. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The timestamp data analysis includes: Perform linear fitting on the timestamp data of multiple frame header signals, and estimate the frequency deviation of the receiver clock by minimizing the difference between the signal arrival timestamp and the ideal timestamp; The fitting process optimizes the error in the calculation process, and finally obtains the accurate frequency deviation between the receiver clock and the base station clock.

6. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The correction of the timestamp data includes: Based on the intensity distribution and time of arrival difference of the captured frame header signals, use the multipath effect modeling to correct the signal timing data; During the correction process, by compensating for the time deviation caused by multipath propagation during signal transmission, further optimize the accuracy of the clock frequency deviation estimation.

7. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The frame header signal capture includes: The receiver continuously listens to the public network synchronization channel, and records the timestamp data each time the signal is captured by detecting the key frames of multiple frame header signals and other signals; During the signal capture process, the receiver classifies and marks different types of synchronization signals.

8. The method for estimating the clock frequency deviation of the public network downlink receiver based on linear fitting according to claim 1, wherein The minimization of the error function includes: Minimize the error between the capture timestamp data of multiple frame header signals and the base station reference timestamp, optimize the fitting function, and obtain the best estimate of the clock frequency deviation; By ensuring the minimization of the error function, reduce the biases caused by external noise, interference, and multipath effects.

9. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The signal delay compensation includes: According to the propagation characteristics of the received frame header signals, combine the arrival time differences of the signals and the intensity distribution of the multipath signals, and compensate for the time delay caused by the multipath effects through modeling; Through multipath compensation, the timestamp data can be accurately estimated and corrected, further improving the accuracy of the frequency deviation estimation.

10. The method for estimating the clock frequency deviation of a public network downlink receiver based on linear fitting according to claim 1, wherein The base station signal synchronization includes: During the process of estimating the clock frequency deviation between the receiver and the base station, continuously update the clock synchronization status of the receiver; Preprocess the captured frame header signals to optimize the signal timing and ensure that the signals are synchronized with the base station after frequency deviation calibration; During the process of estimating the frequency deviation, use real-time monitoring technology to evaluate the quality of the signals.

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